CLEAN COAL TECHNOLOGIES IN JAPAN.pdf

Clean Coal Technologies in Japan Toward the Technology Innovation in the Field of Coal Utilization

New Energy and Industrial Technology Development Organization Center for Coal Utilization, Japan

Clean Coal Technologies in Japan Toward the Technology Innovation in the Field of Coal Utilization

B. Pyrolysis Technologies

Preface ---------------------------------------------------------------------------2

3B1. Multi-Purpose Coal Conversion Technology (CPX)-----------51 Part1 Classification of CCT -----------------------------------------------3

3B2. Coal Flash Partial Hydropyrolysis Technology ----------------53

(1)Classification of CCT in Coal Flow -------------------------------------3

C. Powdering, Flowing, and Co-utilization Technologies

(2)Clean Coal Technology System ----------------------------------------5

3C1. Coal Cartridge System (CCS) ---------------------------------------55

(3)Appreciation of CCT in Markets -----------------------------------------6

3C2. Coal Slurry Production Technology ------------------------------56

(4)CCT in Japanese Industries ---------------------------------------------7

3C3. Briquette Production Technology --------------------------------57

(5)Environmental Technologies --------------------------------------------11

3C4. Coal and Woody Biomass Co-firing Technology -------------59

(6)International Cooperation -----------------------------------------------12

D. De-ashing and Reforming Technologies 3D1. Hyper-Coal based High Efficiency Combustion Technology(Hyper Coal) ---61

Part2 Outline of CCT -------------------------------------------------------13

3D2. Low-Rank Coal Upgrading Technology (UBC Process) ----63

(1) Coal Fired Power Generation Technologies

(4) Environmental Protection Technologies

A. Combustion Technologies

A. Coal Ash Effective Use Technologies

1A1. Pulverized Coal Fired Power Generation Technology(Ultra Super Critical Steam) ----3

4A1. Coal Ash Generation Process and Application Fields -------65

1A2. Circulating Fluidized Bed Combustion Technology (CFBC) ----15

4A2. Effective use for Cement/Concrete ------------------------------67

1A3. Internal Circulating Fluidize Bed Combustion Technology (ICFBC) ----16

4A3. Effective use for Civil Engineering/Construction and Others --69

1A4. Pressurized Internal Circulating Fluidized Bed Combustion Technology (PICFBC) ---17

4A4. Valuable Resources Recovery Technologies for Coal Ash --------71

1A5. Coal Partial Combustor Technology (CPC) ---------------------19

B. Flue Gas Treatment and Gas Cleaning Technologies

1A6. Pressurized Fluidized Bed Combustion Technology (PFBC) ---------------21

4B1. SOx Reduction Technology ----------------------------------------73

1A7. Advanced Pressurized Fluidized Bed Combustion Technology (A-PFBC) ---23

4B2. NOx Reduction Technology ----------------------------------------75

B. Gasification Technologies

4B3. De-SOx and De-NOx Technology --------------------------------77

1B1. Hydrogen-from-Coal Process (HYCOL) -------------------------25

4B4. Soot/dust Treatment Technology and Trace Elements Removal Technology ----79

1B2. Integrated Coal Gasification Combined Cycle (IGCC) -------27

4B5. Gas Cleaning Technology ------------------------------------------81

1B3. Coal Energy Application for Gas, Liquid and Electricity (EAGLE) ------29

C. CO2 Recovery Technologies

(2) Iron Making and General Industry Technologies

4C1. Hydrogen Production by Reaction Integrated Novel Gasification Process (HyPr-RING) --83

A. Iron Making Technologies

4C2. CO2 Recovery and Sequestration Technology ----------------85

2A1. The Formed-Coke making Process (FCP) ----------------------31

4C3. CO2 Conversion Technology -------------------------------------86

2A2. Pulverized Coal Injection for Blast Furnace (PCI) -------------33

4C4. Oxy-fuel Combustion (Oxygen-firing of conventional PCF System) --87

2A3. Direct Iron Ore Smelting Reduction Process (DIOS) ---------35

(5) Basic Technologies for Advanced Coal Utilization

2A4. Super Coke Oven for Productivity and Environment Enhancement toward the 21st Century (SCOPE21) --37

5A1. Modelling and Simulation Technologies for Coal Gasification -----89

B. General Industry Technologies

(6) Coproduction System

2B1. Fluidized Bed Advanced Cement Kiln System (FAKS) ------41

6A1. Co-generation System ----------------------------------------------93

2B2. New Scrap Recycling Process (NSR) ---------------------------39

6A2. Coproduction System ------------------------------------------------95

(3) Multi-Purpose Coal Utilization Technologies Part3 Future Outlook for CCT ------------------------------------------97

A.Liquefaction Technologies 3A1. Coal Liquefaction Technology Development in Japan --------43

Mathematical Table ------------------------------------------------------100

3A2. Bituminous Coal Liquefaction Technology (NEDOL) ----------45 3A3. Brown Coal Liquefaction Technology (BCL) --------------------47 3A4. Dimethylether Production Technology (DME) -------------------49

1

Preface New Energy and Industrial Technology Development Organization (NEDO) and Center for Coal Utilization, Japan (CCUJ) have jointly prepared this brochure to review the history of "Clean Coal Technology (CCT)" in Japan, to systematically describe the present state of CCT to the extent possible, and to enhance the activities toward novel technology innovation on the firm recognition of the present state. NEDO and CCUJ expect that the brochure will be helpful in understanding the CCT of Japan as an attractive technology in the current state of ever-increasing complexity of coal utilization owing to global warming and other environmental issues, and also expect that the brochure will become a starting point of the approaching rapid progress of CCT and the foundation of a coal utilization system. As described herein, CCT progress in Japan has reached the world’s highest level of technological superiority, and consequently, the technology is exceptionally attractive for Asian countries which depend on coal as an energy source. In Japan, coal consumption has rapidly increased since 1998 with thermal power generation efficiency increasing from approximately 38% to 41% over the past decade. In addition, emissions of SOx and NOx per generated power unit from thermal power plants are far below the level of other industrialized countries. In this regard, CCT is expected to establish a worldwide system satisfying both economic and environmental conditions through the efforts of reducing CO2 emissions while maintaining economic growth. Technological innovation has no boundaries, and unlimited progress is attained by sustainable and progressive efforts and by patient and continuous activities to accumulate the effects of technological development and to support an everadvancing society. NEDO and CCUJ are confident that this brochure will be effective in CCT development and anticipate the emergence of epoch-making technological innovations in the coal utilization field. 1.40

Increase in coal consumption and trend of economy, environment, and energy in Japan (1990-2002) 1.35

1.30

Electric power generation

Coal consumption

1.25

1.20

1.15

1.10

GDP

Total primary energy supply CO2 emissions

1.05

Thermal power generation efficiency

1.00

CO2 emissions/GDP 0.95

0.90 1990

1991

1992

1993

1994

1995

1996

2

1997

1998

1999

2000

2001 2002 Fiscal year

Part1 Classification of CCT Classification of CCT in Coal Flow

Carbonization Coal tanker

Pulverizing/Briquetting

Slurry preparation Liquefaction

Gasification

Coal mine

Coal train

DME/GTL CWM

Mining, crushing and pulverizing

Processing, reforming and converting

Transportation and storage

Coal physical properties Anthracite

Bituminous coal

Brown coal

Specific Gravity

1.5~1.8

1.2~1.7

0.8~1.5

Apparent Specific Gravity

-

0.75~0.80

0.55~0.75

Specific heat

0.22~0.24

0.24~0.26

0.26~0.28

Thermal conductivity(W/m K)

-

1.26~1.65

-

Ignition point( )

400~450

300~400

250~300

Multi-purpose utilization technology 4C1

1B1-3

Liquefaction technology

3A1

Coal Liquefaction Technology Development in Japan

3A2

Bituminous Coal Liquefaction Technology (NEDOL)

3A3

Brown Coal Liquefaction Technology (BCL)

3A4

Dimethylether Production Technology (DME)

3B1

Multi-purpose Coal Conversion Technology (CPX)

3B2

Coal Flash Partial Hydropyrolysis Technology

Classification of coal depending on the degree of carbonization

Anthracite Bituminous coal

Subbituminous coal Brown coal

-

Fuel ratio

Caking property

4.0 or more

Non-caking

1.5 or more

8,400 or more

1.5 or less

8,100 or more 7,800 or more

Strong-caking

1.0 or more

Caking

1.0 or less

Weak-caking

1.0 or more

Weak-caking

1.0 or less

Non-caking

7,300 or more

-

Non-caking

6,800 or more

-

Non-caking

5,800 or more

Pyrolysis

Pulvelization, fluidization and co-utilization technology

Coal classification depending on the utilizations (expressed as coal) Indication in TEXT report

Coal in the Trade Statistics

Anthracite

Anthracite

coking coal

coking coal A coking coal B coking coal C

steam coal

coking coal D steam coal A

Strong-caking coal for coke Bituminous Other coal coal for coke Other

steam coal B

High Calorific Value Gas Production Technology

Gasification technology

Heating value(Kcal/kg (on dry basis)) 8,200~8,500 7,500~8,800 5,500~7,500

Classification Heating value (Kcal/kg(on dry basis))

Hydrogen Production Technology in Coal Utilization

3C1 Coal Cartridge System (CCS)

3C2 Coal Slurry Production Technology

3C3 Briquette Production Technology

Ash content of 8% or less 3C4

Coal and Woody Biomass Co-firing Technology

3D1

Hyper-Coal based High Efficiency Combustion Technology(Hyper Coal)

3D2

Low-Rank Coal Upgrading Technology (UBC Process)

Ash content of more than 8% Ash content of 8% or less Deashing and reforming technology

Ash content of more than 8% Ash content of more than 8% Ash content of 8% or less

Other coal steam coal C

Ash content of more than 8%

Basic technology for advanced coal utilization

3

5A1 Modelling and Simulation Technologies

for Coal Gasification

Clean Coal Technologies in Japan CO2 reduction

Flue gas treatment

Power plant Electric precipitator

EOR by CO2

Coal ash effective use

Coal Center Cement plant Flue gas desulfurization unit

Iron works

Flue gas denitration unit

Chemical plant

Environmental countermeasures

Utilization

Coal fired power generation technology

Combustion technology Combustion Technology

Gasification technology

Iron making technology

Flue gas treatment technology 1A1

Pulverized Coal Fired Power Generation Technology(Ultra Super Critical Steam)

4B1

SOx Reduction Technology

1A2

Circulating Fluidized Bed Combustion Technology (CFBC)

4B2

NOx Reduction Technology

1A3

Internal Circulating Fluidize Bed Combustion Technology (ICFBC)

4B2

Intra-furnace Dinitrogen Monoxide Removal Technology

1A4

Pressurized Internal Circulating Fluidized Bed Combustion Technology (PICFBC)

4B3

De-SOx and De-NOx Technology

1A5

Coal Partial Combustor Technology (CPC)

4B4

Soot/dust Treatment Technology and Trace Elements Removal Technology

1A6

Pressurized Fluidized Bed Combustion Technology (PFBC)

4B5

Gas Cleaning Technology

1A7

Advanced Pressurized Fluidized Bed Combustion Technology (A-PFBC)

4C1

Hydrogen Production by Reaction Integrated Novel Gasification Process (HyPr-RING)

3D1

Hyper-Coal utilization High Efficiency Combustion Technology (Hyper Coal)

4C2

CO2 Recovery and Sequestration Technology

CO2 reduction technology

1B1

Hydrogen-from-Coal Process (HYCOL)

4C3

CO2 Conversion Technology

1B2

Integrated Coal Gasification Combined Cycle (IGCC)

4C4

Oxy-fuel Combustion (Oxygen-firing of conventional PCF System)

1B3

Coal Energy Application for Gas, Liquid and Electricity (EAGLE)

4A1

Coal Ash Generation Process and Application Fields

4A2

Effective use for Cement/Concrete

4A3

Soil Improvement Method (FGC)

4A3

Base Materials Production Technology

4A3

High Strength Artificial Aggregate Production Technology

4A3

Agriculture and Fishery Field

4A4

Valuable Resources Recovery Technologies for Coal Ash

4A4

Dry Desulfurization Technology which used Coal Ash

2A1

The Formed-Coke making Process (FCP)

2A2

Pulverized Coal Injection for Blast Furnace (PCI)

2A3

Direct Iron Ore Smelting Reduction Process (DIOS)

2A4

Super Coke Oven for Productivity and Environment Enhancement toward the 21st Century (SCOPE21)

Coal ash utilization technology

Civil field

Architecture field

Fluidized Bed Advanced Cement 2B1 Kiln System (FAKS) Technology for general industries

Yokohama Landmark

2B2

New use development

New Scrap Recycling Process (NSR)

6A1

Co-generation System

6A2

Coproduction System

4

1A1

Classification No. according to the technology overview

1A1

Classification No. according to the related technology overview

Part1 Classification of CCT Clean Coal Technologies in Japan

Clean Coal Technology System

(Coal flow) Coal preparation

Technology for low emission coal utilization

Preparation

(Target)

Conventional coal preparation techniques (jig, floatation, heavy media separation)

Advanced coal cleaning technology

Preparation process control technology

Diversification of energy Sources/expansion of

Bio-briquetting

application fields

Briquetting Carbonization briquetting

Processing

Coal Cartridge System (CCS)

Handling

Coal liquid mixture (CWM,COM) Desulfurized CWM

Ease of handling Bituminous coal liquefaction technology (NEDOL)

Liquefaction

Brown coal liquefaction technology (BCL) Upgrading of Coal-Derived Liquids

Conversion

Integrated coal gasification combined cycle power generation technology (IGCC)

More efficient use of energy/

Coal-based hydrogen production technology (HYCOL)

Gasification

CO2 reduction (as a measure against the

Coal Energy Application for Gas,Liqud and Electricity (EAGLE) Multi-purpose coal conversion (CPX) Coal Flash Partial hydropyrolysis technology

Pyrolysis

Topping cycle.

Combustion

greenhouse effect)

O2/CO2 combustion

High-efficiency combustion

Pressurized fluidized Fluidized bed boiler bed combustion (PFBC)

Reduction in SOx, NOx, and waste (as a measure

Fluidized bed Advanced cement Kilm System(FAKS)

against acid rain) (as a global environmental

Direct Iron-Ore Smelting reduction process(DIOS)

Advanced flue-gas treatment

measure)

Dry desulfurization/ denitration

Wet desulfurization Denitration

Flue gas treatment

Hot gas clean up technology Removal of dust Alkaline, etc. removal technology

Pollutant reduction Ash utilization

Coal Ash Utilization Technologies

(Degree of technology maturity)

Proved reserves and R/P (ratio of reserves to production) of major energy resources

World reserves of coal, oil, and natural gas resources (Saurce: BP 2003) (Unit: 100 million tons oil equivalent) 1,667

Local reserves

World reserves North America S.& Cent. America Europe Former Soviet Union Middle East Africa Asia Pacific

Annual production rate R/P

Natural gas

Oil

Uranium

26.1% 2.3% 13.2% 22.9% 0.2% 5.6% 29.7%

4.4% 4.7% 3.8% 35.4% 36.0% 7.6% 8.1%

4.83 billion ton

2.5 trillion m3

204 years

60.7 years

3.6% 10.6% 1.8% 7.5% 65.4% 7.4% 3.7%

17.9% 6.5% 3.5% 30.6% 0.0% 17.8% 23.8%

1,220

437 1,606

82

561 934

5,012

Russia 589

64 66

133 515

Europe, FSU

556

11

368

109 103 Middle East

27 billion barrel (73.9 million BD) 0.037 million ton 40.6 years

1,260

687

9,845 billion ton 156 trillion m3 1,480 billion barrel 393 million ton

Africa 330

61.1 years

0 0

Prepared from Oil, natural gas, and coal: BP Statistics 2003 Uranium: OECD/NEA,IAEA URANIUM2001

South Africa

North America 3848

2514

1,427 1,430

China 7 7 India

141 98 65

Asia and Oceania 415

South and Central America

4 23 Australia

Worldwide

5

U.S.A.

116 52

Coal Oil Natural gas

Coal

Appreciation of CCT in Markets

Clean Coal Technologies in Japan

Technological difficulty Domestic coal conversion and reforming technology

Domestic coal utilization technology HyPr-RING

P-CPC

Hyper Coal Power Generation

Technical scope in which Technological and economical difficultes remain

IGFC HYCOL

Hyper Coal A-PFBC

Gasification furnace (fluidized bed, spouted bed) IGCC

PFBC Technology at a practical use level

DME

USC FBC

PICFB I C F B Cement raw material P C F B C Gypsum board CFBC

Commercialization technology

Ash-removed CWM CWM COM

Coal Ash utilization Melting and fiber-forming

Flue gas treatment

FGC melting and mixing treatment Fluidized bed solidification material

CCS Pneumatic transfer

NEDOL BCL

CPX

NSR FAKS

Advanced flue gas treatment

PCI

Economic difficulty

Economic difficulty

SCOPE21 DIOS Formed-coke

EAGLE

Artificial aggregate

CC

Simplified dry desulfurization

Briquette Bio-coal Wet coal preparation

Tt

ran

sfe

r

Brown coal dewatering DME

Cost reduction technology development

GTL

Dry coal preparation Hyper Coal

Overseas demonstration (International demonstration cooperated jointly) Conventional technology development region

Overseas coal conversion and reforming technology

Overseas coal utilization technology

Technological difficulty Coal production and consumption by country in 2002 (Total coal production in the world: 3,837 billion ton. Total coal consumption in the world: 3,853 billion ton.) and Coal import to Japan (Total coal import to Japan: 168.5 million ton)

1,326 1,252

917 896

164140 30 58

103 81

U.K.

Poland

3,837 3,853

Source: IEA COAL INFORMATION 2003 Coal Yearbook 2003

30 20 Canada

ex-USSR

(production)

)

.7%

29 60

33.5(19.9%)

Germany 334 357

163 0

China

America

0.4(0.2%)

World 16,317

Japan

15,236 15,457

India

91.8(54.5%)

101 28 Indonesia

11,145

Chemicals 575

276 78 Australia

11,548 Electric power 6,186

9,394

9,079 8,225

Steam coal

223 156

13,057

(Source : Coal Note 2003)

Pulp / paper 491 Gas / coke 412

Coking coal

0.

(Unit: 10 thousand tons)

11 .6% )

.

0 4(

Others 276 Cement/ ceramics 1,296

Trend of coal demand in Japan

19 .6(

)

3%

(consumption)

(5 9.6

Iron making 6,221

FY1970

6

’75

’80

’85

’90

’95

’00

’01

’02

Part1 Classification of CCT Clean Coal Technologies in Japan

CCT in Japanese Industries

Iron making field

Power generation field

Location of iron works

Location of coal fired power plants

Numerals in parentheses designate produced crude steel (MT) as of FY2002.

Numerals in parentheses designate power generate capacity (10 thousand kW) at the end of FY2001.

Sunagawa(25) Naie(35) Tomatou Atsuma (103.5)

Nanao Ota(120) Toyama Shinko Kyodo(50) Noshiro(120)

1600

Domestic total coal consumption

140

1400

120

1200

Generated power 100

1000

80

800

60

600

Coal consumption

40

400

20

200

0

0

1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Shin-onoda(100) Shimonoseki(17.5) Kanda(36) Minato(15.6) Matsuura(270) Omura(15.6) Matsushima(100)

Sendai(52.5) Shinchi(200) Haramachi(200) Hirono (under construction) Nakoso(145) Hitachi Naka (100)

Tachibanawan(210+70)

Reihoku(70)

Kin(22)

Saijo(40.6)

Ishikawa(31.2) Gushikawa(31.2)

JFE Steel (Chiba)(4,186,020)

JFE Steel (Fukuyama)(9,885,534)

Nippon Steel (Kimitsu) (9,195,689)

180

180

160

160

Hekinan(310)

Sumitomo Metal (Kashima)(6,820,450)

JFE Steel (Mizushima)(8,423,478)

Isogo (120)

Domestic total coal consumption

140 120

140 120

Crude steel production

100

100 80

80

Coal consumption

60

60

40

40

20

20

Nippon Steel (Yawata) (3,514,941)

JFE Steel (Keihin)(3,472,723) Nippon Steel (Nagoya)(5,651,300) Sumitomo Metal (Wakayama)(3,412,887) Nippon Steel (Oita)(8,012,585)

0

0 1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Coal consumption in iron making sector and crude steel production

Coal consumption in power generation sector and generated power

Coal fired power generation technology

Steam coal

Kobe Steel (Kakogawa)(5,397,267)

Crude steel production (million ton)

1800

160

Kobe Steel (Kobe)(1,062,063)

Sakata(70)

Coal consumption (million ton)

180

Generated power (GkWh)

Coal consumption (million ton)

Tsuruga(120) Maizuru (under construction) Takasago(50) Mizushima(28.1) Osaki(25) Takehara(130) Misumi(100)

1A1

Pulverized Coal Fired Power Generation Technology(Ultra Super Critical Steam)

1A4

Pressurized Internal Circulating Fluidized Bed Combustion Technology (PICFBC)

1A2

Circulating Fluidized Bed Combustion Technology (CFBC)

1A5

Coal Partial Combustor Technology (CPC)

1A3

Internal Circulating Fluidize Bed Combustion Technology (ICFBC)

1A6

Pressurized Fluidized Bed Combustion Technology (PFBC)

1A7

Advanced Pressurized Fluidized Bed Combustion Technology (A-PFBC)

Iron making technology 2A2

Pulverized Coal Injection for Blast Furnace (PCI)

2A1

The Formed-Coke making Process (FCP)

Blast furnace Coking coal

Pig iron

Formed-coke furnace

Converter

Combustion furnace boiler PCI

Coal

Electric furnace

Gas cleaning

Stack

Coal Pulverized coal

gasification furnace

Gas

Steam

turbine

turbine

Iron and steel Coal

Generator

SCOPE21 Slag

Steam coal 4B5

Electric power

Gas Cleaning Technology

DIOS Wastewater 1B1

Hydrogen-from-Coal Process (HYCOL)

1B3

Coal Energy Application for Gas, Liquid and Electricity (EAGLE)

3D1

Hyper-Coal based High Efficiency Combustion Technology (Hyper Coal)

NSR 2A4

1B2

Integrated Coal Gasification Combined Cycle (IGCC)

Super Coke Oven for Productivity and Environment Enhancement toward the 21st Century (SCOPE21)

2A3

Direct Iron Ore Smelting Reduction Process (DIOS) 2B2

7

8

New Scrap Recycling Process (NSR)

Part1 Classification of CCT Clean Coal Technologies in Japan

CCT in Japanese Industries

Iron making field

Power generation field

Location of iron works

Location of coal fired power plants

Numerals in parentheses designate produced crude steel (MT) as of FY2002.

Numerals in parentheses designate power generate capacity (10 thousand kW) at the end of FY2001.

Sunagawa(25) Naie(35) Tomatou Atsuma (103.5)

Nanao Ota(120) Toyama Shinko Kyodo(50) Noshiro(120)

1600

Domestic total coal consumption

140

1400

120

1200

Generated power 100

1000

80

800

60

600

Coal consumption

40

400

20

200

0

0

1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Shin-onoda(100) Shimonoseki(17.5) Kanda(36) Minato(15.6) Matsuura(270) Omura(15.6) Matsushima(100)

Sendai(52.5) Shinchi(200) Haramachi(200) Hirono (under construction) Nakoso(145) Hitachi Naka (100)

Tachibanawan(210+70)

Reihoku(70)

Kin(22)

Saijo(40.6)

Ishikawa(31.2) Gushikawa(31.2)

JFE Steel (Chiba)(4,186,020)

JFE Steel (Fukuyama)(9,885,534)

Nippon Steel (Kimitsu) (9,195,689)

180

180

160

160

Hekinan(310)

Sumitomo Metal (Kashima)(6,820,450)

JFE Steel (Mizushima)(8,423,478)

Isogo (120)

Domestic total coal consumption

140 120

140 120

Crude steel production

100

100 80

80

Coal consumption

60

60

40

40

20

20

Nippon Steel (Yawata) (3,514,941)

JFE Steel (Keihin)(3,472,723) Nippon Steel (Nagoya)(5,651,300) Sumitomo Metal (Wakayama)(3,412,887) Nippon Steel (Oita)(8,012,585)

0

0 1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Coal consumption in iron making sector and crude steel production

Coal consumption in power generation sector and generated power

Coal fired power generation technology

Steam coal

Kobe Steel (Kakogawa)(5,397,267)

Crude steel production (million ton)

1800

160

Kobe Steel (Kobe)(1,062,063)

Sakata(70)

Coal consumption (million ton)

180

Generated power (GkWh)

Coal consumption (million ton)

Tsuruga(120) Maizuru (under construction) Takasago(50) Mizushima(28.1) Osaki(25) Takehara(130) Misumi(100)

1A1

Pulverized Coal Fired Power Generation Technology(Ultra Super Critical Steam)

1A4

Pressurized Internal Circulating Fluidized Bed Combustion Technology (PICFBC)

1A2

Circulating Fluidized Bed Combustion Technology (CFBC)

1A5

Coal Partial Combustor Technology (CPC)

1A3

Internal Circulating Fluidize Bed Combustion Technology (ICFBC)

1A6

Pressurized Fluidized Bed Combustion Technology (PFBC)

1A7

Advanced Pressurized Fluidized Bed Combustion Technology (A-PFBC)

Iron making technology 2A2

Pulverized Coal Injection for Blast Furnace (PCI)

2A1

The Formed-Coke making Process (FCP)

Blast furnace Coking coal

Pig iron

Formed-coke furnace

Converter

Combustion furnace boiler PCI

Coal

Electric furnace

Gas cleaning

Stack

Coal Pulverized coal

gasification furnace

Gas

Steam

turbine

turbine

Iron and steel Coal

Generator

SCOPE21 Slag

Steam coal 4B5

Electric power

Gas Cleaning Technology

DIOS Wastewater 1B1

Hydrogen-from-Coal Process (HYCOL)

1B3

Coal Energy Application for Gas, Liquid and Electricity (EAGLE)

3D1

Hyper-Coal based High Efficiency Combustion Technology (Hyper Coal)

NSR 2A4

1B2

Integrated Coal Gasification Combined Cycle (IGCC)

Super Coke Oven for Productivity and Environment Enhancement toward the 21st Century (SCOPE21)

2A3

Direct Iron Ore Smelting Reduction Process (DIOS) 2B2

7

8

New Scrap Recycling Process (NSR)

Part1 Classification of CCT Clean Coal Technologies in Japan

CCT in Japanese Industries

Cement production field

Coal chemicals and other fields Location of cement plants

Location of chemicals complexes Numerals in parentheses designate ethylene production capacity (1000 t/y) at the end of FY2002.

Numerals in parentheses designate clinker production capacity (1000 t/y) as of April 1, 2003.

Nittetsu Cement (Muroran)(968)

Myojo Cement (Itoigawa)(2,108) Denki Kagaku Kogyo (Omi)(2,703)

Taiheiyo Cement (Kamiiso)(3,944) Mitsubishi Material (Aomori)(1,516)

Sumitomo Osaka Cement (Gifu)(1,592)

Hachinohe Cement (Hachinohe)(1,457)

Tsuruga Cement (Tsuruga)(816)

Taiheiyo Cement (Ofunato)(2,680)

180 160

Domestic total coal consumption

140

140

120

120

Cement production

100

100

80

80

60

60

40

40

Coal consumption

20 0

20

Cement production (million ton)

Coal consumption (million ton)

160

0 1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Coal consumption in cement production sector and cement production

Taiheiyo Cement (Fujiwara)(2,407) Taiheiyo Cement (Tosa)(1,165) Taiheiyo Cement (Kochi)(4,335) Taiheiyo Cement (Tsukumi)(4,598) Taiheiyo Cement (Saeki)(1,426)

Nippon Steel Blast Furnace Cement (Tobata)(808) Mitsubishi Materials (Kyushu)(8,039) Ube Industries (Kanda)(3,447) Kanda Cement (Kanda)(1,085) Kawara Taiheiyo Cement (Kawara)(800) Mitsui Mining (Tagawa)(1,977) Aso Cement (Tagawa)(1,412)

4,600

540 (19.5)

4,400

GDP

4,200

(19.0)

(16.9) (16.5)

318.6 316.0

(16.1) (16.0) 307.1

309.1

317.3

316.7

311.4 307.4

303.3

291.4 286.1

Nippon Petrochemicals (Kawasaki)(404) Tonen Chemical (Kawasaki)(478) Mitsubishi Chemical (Yokkaichi) Tosoh (Yokkaichi)(493) Mitsui Chemicals (Osaka) Osaka Petrochemical (455) Showa Denko (Oita)(581)

380

294.5 291.0

1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02 Ryukyu Cement (Yabu)(722)

420 400

CO2 emissions (Mt-C)

3,000 2,800

440

(16.3)

3,400 3,200

460

(16.7) (16.3) (17.2) (16.5) (16.4)

3,600

520

480

Coal energy supply

3,800

Mitsui Chemicals (Ichihara)(553) Idemitsu Petrochemical (Chiba)(374) Sumitomo Chemical (Anegasaki, Sodegaura)(380)

500

(17.8) (17.8)

4,000

Mitsubishi Chemical (Kashima)(828) Maruzen Petrochemical (Goi)(480) Keihin Ethylene(690)

Mitsui Chemicals (Iwakuni-otake)(623) Idemitsu Petrochemical (Suo)(623)

GDP (trillion yen)

Hitachi Cement (Hitachi)(848) Sumitomo Osaka Cement (Tochigi)(1,489) Chichibu Taiheiyo Cement (Chichibu)(800) Taiheiyo Cement (Kumagaya)(2,267) Mitsubishi Material (Yokoze)(1,213) Taiheiyo Cement (Saitama)(1,655) DC (Kawasaki)(1,108)

Ube Industries (1,612) Ube Industries (4,872)

Coal energy supply (PJ)

Tokuyama (Nanyo)(5,497) Tosoh (2,606)

180

Mitsubishi Chemical (Mizushima)(450) Asahi Kasei (Mizushima) Sanyo Petrochemical (443)

Mitsubishi Material (Iwate)(670)

360 Ryukyu Cement (Yabu)(722)

Coal energy supply, GDP, and CO2 emissions in Japan Numerals in parentheses designate the percentage of coal in primary energy.

Coal chemicals process Cement production technology

3A1

Coal Liquefaction Technology Development in Japan

3A4

Dimethylether Production Technology (DME)

3A2

Bituminous Coal Liquefaction Technology (NEDOL)

4C1

Hydrogen Production by Reaction Integrated Novel Gasification Process (HyPr-RING)

Coal 2B1

3A3

Fluidized Bed Advanced Cement Kiln System (FAKS) Coal

Electric precipitator

4A2

Vent

(Fractionation process)

Effective use for Cement/Concrete

Electric precipitator

Brown Coal Liquefaction Technology (BCL)

(Raw material charge process)

Track

Medium distillate

(Coal conversion process)

Gypsum

Heavy distillate Limestone Clay Iron raw material

Cement cooler

Coal mill

Water

Cement silo

(Separation, purification process)

Drier Heavy oil tank

Recycle raw material Air separator

Air

Silo

High value-added product BTX and mono- and di-cyclic components

Tanker Raw material mill

Preheater

Air separator Rotary kiln

Residue coal (Recycle) Wastewater

Clinker cooler Clinker silo

Pre-pulverizing mill

Multi-Purpose Coal Conversion Technology (CPX)

3D1

3B2 Coal Flash Partial Hydropyrolysis

3D2

3B1

Technology

9

10

Hyper-Coal based High Efficiency Combustion Technology(Hyper Coal) Low-Rank Coal Upgrading Technology (UBC Process)

Part1 Classification of CCT Clean Coal Technologies in Japan

CCT in Japanese Industries

Cement production field

Coal chemicals and other fields Location of cement plants

Location of chemicals complexes Numerals in parentheses designate ethylene production capacity (1000 t/y) at the end of FY2002.

Numerals in parentheses designate clinker production capacity (1000 t/y) as of April 1, 2003.

Nittetsu Cement (Muroran)(968)

Myojo Cement (Itoigawa)(2,108) Denki Kagaku Kogyo (Omi)(2,703)

Taiheiyo Cement (Kamiiso)(3,944) Mitsubishi Material (Aomori)(1,516)

Sumitomo Osaka Cement (Gifu)(1,592)

Hachinohe Cement (Hachinohe)(1,457)

Tsuruga Cement (Tsuruga)(816)

Taiheiyo Cement (Ofunato)(2,680)

180 160

Domestic total coal consumption

140

140

120

120

Cement production

100

100

80

80

60

60

40

40

Coal consumption

20 0

20

Cement production (million ton)

Coal consumption (million ton)

160

0 1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02

Coal consumption in cement production sector and cement production

Taiheiyo Cement (Fujiwara)(2,407) Taiheiyo Cement (Tosa)(1,165) Taiheiyo Cement (Kochi)(4,335) Taiheiyo Cement (Tsukumi)(4,598) Taiheiyo Cement (Saeki)(1,426)

Nippon Steel Blast Furnace Cement (Tobata)(808) Mitsubishi Materials (Kyushu)(8,039) Ube Industries (Kanda)(3,447) Kanda Cement (Kanda)(1,085) Kawara Taiheiyo Cement (Kawara)(800) Mitsui Mining (Tagawa)(1,977) Aso Cement (Tagawa)(1,412)

4,600

540 (19.5)

4,400

GDP

4,200

(19.0)

(16.9) (16.5)

318.6 316.0

(16.1) (16.0) 307.1

309.1

317.3

316.7

311.4 307.4

303.3

291.4 286.1

Nippon Petrochemicals (Kawasaki)(404) Tonen Chemical (Kawasaki)(478) Mitsubishi Chemical (Yokkaichi) Tosoh (Yokkaichi)(493) Mitsui Chemicals (Osaka) Osaka Petrochemical (455) Showa Denko (Oita)(581)

380

294.5 291.0

1990 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02 Ryukyu Cement (Yabu)(722)

420 400

CO2 emissions (Mt-C)

3,000 2,800

440

(16.3)

3,400 3,200

460

(16.7) (16.3) (17.2) (16.5) (16.4)

3,600

520

480

Coal energy supply

3,800

Mitsui Chemicals (Ichihara)(553) Idemitsu Petrochemical (Chiba)(374) Sumitomo Chemical (Anegasaki, Sodegaura)(380)

500

(17.8) (17.8)

4,000

Mitsubishi Chemical (Kashima)(828) Maruzen Petrochemical (Goi)(480) Keihin Ethylene(690)

Mitsui Chemicals (Iwakuni-otake)(623) Idemitsu Petrochemical (Suo)(623)

GDP (trillion yen)

Hitachi Cement (Hitachi)(848) Sumitomo Osaka Cement (Tochigi)(1,489) Chichibu Taiheiyo Cement (Chichibu)(800) Taiheiyo Cement (Kumagaya)(2,267) Mitsubishi Material (Yokoze)(1,213) Taiheiyo Cement (Saitama)(1,655) DC (Kawasaki)(1,108)

Ube Industries (1,612) Ube Industries (4,872)

Coal energy supply (PJ)

Tokuyama (Nanyo)(5,497) Tosoh (2,606)

180

Mitsubishi Chemical (Mizushima)(450) Asahi Kasei (Mizushima) Sanyo Petrochemical (443)

Mitsubishi Material (Iwate)(670)

360 Ryukyu Cement (Yabu)(722)

Coal energy supply, GDP, and CO2 emissions in Japan Numerals in parentheses designate the percentage of coal in primary energy.

Coal chemicals process Cement production technology

3A1

Coal Liquefaction Technology Development in Japan

3A4

Dimethylether Production Technology (DME)

3A2

Bituminous Coal Liquefaction Technology (NEDOL)

4C1

Hydrogen Production by Reaction Integrated Novel Gasification Process (HyPr-RING)

Coal 2B1

3A3

Fluidized Bed Advanced Cement Kiln System (FAKS) Coal

Electric precipitator

4A2

Vent

(Fractionation process)

Effective use for Cement/Concrete

Electric precipitator

Brown Coal Liquefaction Technology (BCL)

(Raw material charge process)

Track

Medium distillate

(Coal conversion process)

Gypsum

Heavy distillate Limestone Clay Iron raw material

Cement cooler

Coal mill

Water

Cement silo

(Separation, purification process)

Drier Heavy oil tank

Recycle raw material Air separator

Air

Silo

High value-added product BTX and mono- and di-cyclic components

Tanker Raw material mill

Preheater

Air separator Rotary kiln

Residue coal (Recycle) Wastewater

Clinker cooler Clinker silo

Pre-pulverizing mill

Multi-Purpose Coal Conversion Technology (CPX)

3D1

3B2 Coal Flash Partial Hydropyrolysis

3D2

3B1

Technology

9

10

Hyper-Coal based High Efficiency Combustion Technology(Hyper Coal) Low-Rank Coal Upgrading Technology (UBC Process)

Part1 Classification of CCT Clean Coal Technologies in Japan

Environmental Technologies

2)Coal ash effective use technology

1)Flue gas treatment technology

4)Environmental Protection and fuel conversion technology (DME, GTL)

3)Global warming countermeasures technology (Technology to reduce CO2 emissions)

Flue gas treatment technology

Effective coal ash utilization in Japan

Emission reduction technology to remove dust, sulfur oxides,

Ash generated during coal combustion is effectively

and nitrogen oxides is developed by treating and combusting

used as raw material for cement and other applications.

flue gas from coal combustion through superior process design. Mechanism of flue gas denitration unit

Mechanism of electrostatic precipitator

Power in Japan: Effective use of coal ash generated from general industries, (FY2002) (Source: Center for Coal Utilization, Japan)

Mechanism of flue gas desulfurization unit

Agriculture, forestry, and fishery fields 1.8%

NH3 (Ammonia) NO X

DC high voltage

NO X NO X

Electrode

NO X

Clean gas (to stack)

NO X

NH 3

Fertilizer, soil improving material, etc. 139 1.8%

NO X

NH 3

Other building materials 29 0.4%

NH 3 NO X

NH 3

NO X

Pump

Catalyst

Discharge electrode Collected coal ash Collecting electrode

Mixed liquor of limestone and water H 2O

N2 N2

Other 5.8%

Building material board 347 4.5%

Flue gas

N2

H 2O

Civil work material, etc. 134 1.7%

N2

Gypsum

Pump

Gypsum

Total 7,724

Architecture field 4.9%

H 2O H 2O

Cement raw material 5,694 73.7%

Other 446 5.8%

(thousand ton)

Cement field 78.7%

Civil field 8.8%

Flue gas (from boiler)

Road and base materials 115 1.5%

Electrostatic Precipitator Flue gas passes between two electrodes that are charged by a high voltage current. The ash and dust are negatively charged, and are attracted toward and deposit on the cathode. The ash and dust deposited on the cathode where periodical hammering occurs are collected in the lower section of the electrostatic precipitator and subsequently removed. The principle is the same with the phenomenon that paper and dust adhere to a celluloid board electrostatically charged by friction. Flue Gas Desulfurizer Limestone is powdered to prepare a water-based mixture (limestone slurry). The mixture is sprayed into the flue gas to induce a reaction between the limestone and the sulfur oxides in the flue gas to form calcium sulfite, which is further reacted with oxygen to form gypsum. The gypsum is then separated as a product. Flue Gas Denitrizer Ammonia is added to the flue gas containing nitrogen oxides. The mixture gas is introduced to a metallic catalyst (a substance to induce chemical reactions). The nitrogen oxides in the flue gas undergo catalyst-induced chemical reactions to decompose into nitrogen and water.

Cement admixture 239 3.1% Concrete admixture 147 1.9%

Coal mine filler 188 2.4%

Ground improving material 246 3.2%

CO2 emissions in Japan CO 2 emissions in Japan for individual sectors (Source: Headquarters of Countermeasures to Global Warming (FY2000))

Other (non-fuel sector, etc.) 2.0% (direct incineration: 2.0%) Waste (plastics and waste oil incineration) 2.0% (direct incineration: 2.0%) Energy conversion sector (power plant, etc.) 6.9% (direct incineration: 30.9%)

Industrial process (limestone consumption) 4.3% (direct incineration: 4.3%)

3 Transportation sector (automobile, Energy-related ship, and aircraft) sectors 20.7% (direct incineration: 20.2%)

(93.7%)

Commercial sector (Business) 12.3% (direct incineration: 5.2%)

Industry sector 40.0% (direct incineration: 31.0%)

Commercial sector (Household) 13.5% (direct incineration: 6.0%)

Reaction formulae

4NO + 4NH3 + O2

CO2 emissions in major countries (million ton as carbon)

4N2 + 6H2O

(Nitrogen (Ammonia) monoxide)

(Nitrogen gas)

6NO2 + 8NH3

7N2 + 12H2O

(Nitrogen dioxide)

USA

(Nitrogen gas)

1990

2000

2001

2005

2010

Mt-C

1,352

1,578

1,559

1,624

1,800 2,082

23.0

26.9

26.5

27.7

Source; The Federation of Electric Power Companies of Japan

(g/kWh) 9

(Thermal power plant)

7.1

SOx

8

NOx

7

30.7

35.5

Mt-C

129

158

155

172

186

196

UK

Mt-C

164

151

153

155

163

176

France

Mt-C

102

109

108

106

108

122

Germany

Mt-C

271

226

223

224

232

241

Italy

Mt-C

113

121

121

124

129

140

ex-USSR

Mt-C

1,036

638

654

780

825

939

17.6

10.9

11.1

13.3

14.0

16.0

617

780

832

888

6

3.0

3.2

1.4

1

0.9

1.2

0.7

10.5

13.3

14.2

15.1

18.9

26.8

153

249

250

272

321

435

Japan

Mt-C

269

310

316

319

334

365

4.6

4.8

4.8

4.6

4.3

3.9

5,872

6,417

6,522

6,908

%

UK America Italy Canada Germany Japan (1999) (1999) (1999) (1999) (2002)

World total

11

1,109 1,574

Mt-C

% 2.0

0.20 0.26 France (1998)

Mt-C

India

2.7 2.1

2 0

China

4.0

4 3

%

4.8

5

2020

Canada

%

Emissions of SOx and NOx per generated power in major countries

(Source: IEO 2004)

Unit

Mt-C

7,685 9,372

Part1 Classification of CCT Clean Coal Technologies in Japan

International Cooperation 1)Pollution countermeasures technology (SOx, NOx, and dust/soot reduction technology)

2)High efficiency power generation technology (IGCC, IGFC) 3)CO2 emissions reduction technology (CDM, JI countermeasures technology)

From GAP to CDM In recent years, the global warming issue has attracted intense international concern. Global warming is a serious problem for the future of the earth and humankind, and is closely related to human economic activity and the accompanying energy consumption. Thus, satisfying both "economic development" and "the environment" becomes an important issue. The Kyoto Protocol, adopted at Kyoto in December 1997 and ratified by Japan in June 2002, includes the "Kyoto Mechanisms", an important instrument of international cooperation. In particular, the Kyoto Mechanisms include a market mechanism called the Clean Development Mechanism (CDM), which is a forthcoming system that aims to reduce greenhouse gases through cooperation between developed and developing countries. From the viewpoint of overcoming global environmental issues that continue to spread worldwide, developing countries are requested to maximize their self-help efforts toward improvement of the environment in order to prevent ever-increasing pollution and global warming. Japan is requested to contribute to the economic growth and environmental improvement of developing countries through the active introduction of Japanese Clean Coal Technology (CCT) into Asian countries such as China, which are expected to show continued increases in coal consumption.

Current state of international cooperation Concomitant with the progress of industrialization and urbanization, developing countries face serious air and water pollution issues. Particularly in Asia and Oceania, the percentage of coal in the energy mix is large and sustainable economic development further emphasizes the importance of the development and widespread dissemination of coal utilization technology with full-scale environmental conservation measures. Since developing countries do not have sufficient capital, technology, and human resources for such technology, self-help efforts are limited, and the assistance of developed countries including Japan and of international organizations is requested. Japan has promoted international cooperation in terms of "pollution countermeasure technology" to reduce emissions of SOx, NOx, and dust, and of "high efficiency power generation technology" to improve energy use efficiency with a focus on the Green Aid Plan (GAP) counterpart countries of China, Indonesia, Thailand, Malaysia, the Philippines, India, and Vietnam.

List of clean coal technologies and model projects relating to GAP Project name

Project period

Target country

Site

Cleaning after combustion Simplified desulfurization unit

Coke oven gas desulfurization unit

FY1993-FY1995

People’s Republic of China

FY1995-FY1997

Thailand

FY1998-FY2001

People’s Republic of China

FY1999-FY2002

People’s Republic of China

Cleaning during combustion, improvement of combustion efficiency Circulating fluidized bed boiler

FY1993-FY1995

People’s Republic of China

Philippines FY1995-FY1997

People’s Republic of China Indonesia

FY1996-FY1998

People’s Republic of China

FY1996-FY1999

People’s Republic of China

FY1997-FY1999

Thailand

FY1997-FY2001

People’s Republic of China

Cleaning before combustion Briquette production unit

FY1993-FY1995

People’s Republic of China Indonesia

FY1996-FY1998

Indonesia

FY1997-FY1999

Thailand

FY1998-FY2002

Philippines

Water-saving coal preparation system

FY1994-FY1997

People’s Republic of China

Desulfurization type CWM unit

FY1995-FY1998

People’s Republic of China

12

Electricity Generating Authority of Thailand (Lampang)

Counterpart

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

1A1. Pulverized Coal Fired Power Generation Technology (Ultra Super Critical Steam) Outline of technology

1.Efficiency increase Increase in the thermal efficiency of power generation plant is an important issue in terms not only of economy to decrease the

600OC

power generation cost but also of suppression of CO2 emissions.

566OC

538OC

In particular, coal fired power plants which are the main stream of

conditions in recent years. In 1989, Kawagoe No.1 plant (700 MW) of Chubu Electric Power Co., Inc. adopted steam condition of 316 kg/cm2G (31.0 MPa) x 566 C/566 C/566 C. In 1993, Hekinan No.3 plant (700 MW) of O

the company adopted the steam condition of 246

kg/cm2G

31.0MPa

24.5MPa

Steam temperature 500 (Left scale)

30 24.1MPa 16.6MPa

400

20

Steam pressure (Right scale)

300

Steam pressure MPa

Steam temperature OC

temperature level. The right figure summarizes the trend of steam

O

593OC

600

current large thermal power plants increase their steam

O

610OC

10

(24.1 200

MPa) x 538OC/593OC, which 593OC was the first highest temperature of reheated steam in Japan. After that, Misumi No.1

0

1910

plant (1000 MW) of The Chugoku Electric Power Co., Inc. and

1920

1930

1940

1950

1960

1970

1980

1990

2000

Fig. 1 Changes in steam condition with time

Haramachi No.2 plant (1000 MW) of Tohoku Electric Power Co., Inc. adopted the steam condition of 24.5 MPa x 600OC/600OC in 1998. Furthermore, Tachinbanawan No.1 and No.2 plant (1050 MW) of Electric Power Development Co., Ltd. adopted the steam condition of 25.0 MPa x 600OC/610OC in 2000. The figure below

5 Efficiency increase rate (%)

shows an example of relation between the steam condition and the increase in efficiency at a supercritical pressure plant. Responding to the movement of increase in the steam temperature, power companies, steel manufacturers, and boiler manufacturers

promote

the

development

and

practical

application of high strength materials having superior high temperature corrosion resistance, steam-oxidation resistance,

4 3 2 1 0

and workability. The high-temperature materials for 650OC level

Temperature of main steam (OC)

538

538

566

600

625

use have already been in the practical application stage, and the

Temperature of reheated steam (OC) 566

593

593

600

625

(Base)

study proceeds to satisfy 700OC level use aiming at further high efficiency of the thermal plants.

The figure below shows the

Fig. 2 Relation between the steam condition and the efficiency improvement at supercritical pressure plants

steam conditions and the high temperature materials for the respective steam conditions. Fig. 3 Steam conditions and high temperature materials Steam temperature (OC)

538

Main steam pipe

2.25Cr 1Mo

Superheater tube

18 Cr

Hot reheat pipe

2.25Cr 1Mo

Reheater tube

9 Cr

: Ferritic Material

566

593

9 Cr

621

12 Cr

649

18 Cr

20-25 Cr

9 Cr

18 Cr

: Austenitic Material

13

12 Cr

20-25 Cr

18 Cr

Clean Coal Technologies in Japan

2.Combustion technology Various combustion technologies have been developed and

intrafurnace denitration using the whole zones in the furnace.

practically applied responding to the need to satisfy current

(1) Low NOx combustion at coal burner

severe environmental regulations and to respond to the high

Although the structure of burner differs between large-boiler

efficiency combustion.

The emission level of NOx and dust

manufacturers, the most advanced burners basically adopt the

generated during the combustion of coal is the world’s lowest

separation of dense and lean pulverized coal streams and the

level even at boiler exit, though the ultimate emission level owes

multilayer charge of combustion air aiming to attain the ignitability

the flue gas treatment given at downstream side of the boiler.

increase and to conduct the intraflame denitration. Figures 4 to 7

Since emission of NOx and that of dust are very closely related to

show the burner structure of several manufacturers.

each other, this paper focuses on the low NOx combustion technology.

The low NOx combustion technology is roughly

grouped to the suppression of NOx generation at burner and the

Dense flame

Enhancing intraflame denitration combustion by the outer periphery stable ignition Secondary air Tertiary air

Tertiary air

Tertiary air swirling vane Secondary air

Lean flame

Distributor vane Oil burner Reducing flame

Dense flame Lean flame Dense flame

Primary air + Pulverized coal Primary throat Secondary throat

Dense flame Lean flame Dense flame

Primary flame holding plate Secondary flame holding plate

Rib

Fig.5 CC type pulverized coal fired burner: Kawasaki Heavy Industries, Ltd.

Fig.4 Pulverized coal fired A-PM burner: Mitsubishi Heavy Industries, Ltd. Burner inner cylinder Primary air + Pulverized coal

Burner outer cylinder

Secondary air inner vane Secondary air vane Flow detector Throat ring

Tertiary air damper Primary air (Pulverized coal + Air)

Oil burner Primary air + Pulverized coal Tertiary air

Furnace wall tube Outer secondary air

Oil burner support Secondary air vane driver Secondary air inner vane driver

Secondary air

Inner periphery Outer periphery secondary air secondary air Volatile matter combustion zone

NOx decomposition zone

Reducing agent generation zone

Char combustion enhancing zone

Fig.7 Pulverized coal fired NR burner: Babcock-Hitachi K.K.

Inner secondary air

Fig.6 DF intervene pulverized coal fired burner: Ishikawajima-Harima Heavy Industries Co., Ltd. Furnace exit

(2) Intrafurnace denitration

Combustion completion zone

Intrafurnace denitration is conducted by reducing the NOX Aditional Air

generated in the main burner zone using the residual

NOx reducing zone containing unburned fuel

hydrocarbons or the hydrocarbons generated from small amount of fuel oil charged from the top of the main burner.

The Over Fire Air

intrafurnace denitration is performed in two stages. Figure 3 is

Main burner combustion zone

the conceptual drawing of the intrafurnace denitration. In the first stage, hydrocarbons reduce NOx.

Main burner

In the second

stage, the unburned matter is completely combusted by the additionally charged air. Fig.8 Conceptual drawing of intrafurnace denitration 14

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

1A2. Circulating Fluidized Bed Combustion Technology (CFBC) Outline of technology

1.Features The features of circulating fluidized bed boiler are described

NOx depending on temperature) are suppressed. In addition, the

below.

operation of circulating fluidized bed boiler is conducted by two-

1)Wide range of fuel adaptability

stage combustion: the reducing combustion at the fluidized bed

Conventional boilers for power generation can use only fossil fuel

section; and the oxidizing combustion at the freeboard section.

such as high grade coal, oil, and gas. The CFBC also uses low

Then, the unburnt carbon is collected by a high temperature

grade coal, biomass, sludge, waste plastics, and waste tire as fuel.

cyclone located at exit of the boiler to recycle to the boiler, thus

2)Low pollution

increasing the denitration efficiency.

Emissions of pollutants such as NOx and SOx are significantly

3)High combustion efficiency

decreased without adding special environment measures. For

High combustion efficiency is attained by excellent combustion

the case of fluidized bed boiler, the desulfurization is intrafurnace

mechanism of circulating fluidization mode.

desulfurization using mainly limestone as the fluidizing material.

4)Space saving and high maintenance ability

For the denitration, ordinary boilers operate at combustion

Space saving is attained because there is no need of separate

temperatures from 1,400 C to 1,500 C, and the circulating

desulfurization unit, denitration unit, and fuel finely crashing unit.

fluidized bed boiler operates at lower temperatures ranging from

Accordingly, sections of trouble occurrence become few, and

850 C to 900 C so that the thermal NOx emissions (generated

maintenance becomes easy.

O

O

O

O

2.Outline of technology Figure 1 shows a typical process flow of CFBC

Hot cyclone

CFBC boiler body

Generated steam Coal Limestone

Flue gas Boiler feed water heater

Boiler feed water

Circulating fluidized bed furnace

Secondary air Primary air

Cyclone

Air preheater

Electric precipitator Heat recovery section

ID fan

Stack

Ash storage tank

Fig.1 Process flow of circulating fluidized bed boiler

Figure 2 shows rough structure of CFBC.

Generally CFBC is

structured by the boiler and the high temperature cyclone.

Fig.2 Schematic drawing of CFBC structure

The

intrafurnace gas velocity is as high as 4 to 8 m/s. Coarse fluidizing

increase the thermal efficiency, a preheater for fluidizing air and

medium and char in the flue gas are collected by the high

combustion air, and a boiler feed water heater are installed. Most of

temperature cyclone, and are recycled to the boiler. The recycle

the boiler technologies are introduced from abroad: mainly from

maintains the bed height and increases the denitration efficiency. To

Foster Wheeler, Lurgi, Steinmuller, ALSTOM, and Babcock & Wilcox.

3.Study site and application field Photograph 1 shows overview of the CFBC boiler facilities. The CFBC

Co., Ltd., and Isa plant (210 t/h) of Ube

became popular mainly as coal fired boilers. Recently, however, CFBC

Industries, Ltd. Example of RDF fired boiler is

using RDF and wood-base biomass as the fuel has drawn attention.

Tomakomai plant of Sanix Inc.

Typical applications of coal fired biogas are Tamashima plant (70 t/h) of

biomass fuel, mixed combustion with coal is

Kuraray Co., Ltd, Chiba worksoil refinery (300 t/h) of Idemitsu Kosan

adopted for decrease of CO2 emission.

As for the

4.Study period Most of the technologies of circulating normal pressure fluidized bed boiler (CFBC) are introduced into Japan from abroad beginning from around 1986.

Photo 1 CFBC appearance

5.Progress and result of the development The CFBC was introduced from abroad as the coal fired boiler,

of CFBC include further investigations of and efforts for initial cost

and is used in power companies, iron making companies, paper

and power generation efficiency in the boilers using fuel such as

making companies, and other sectors. The CFBC is planned to

RDF, industrial waste, and wood-base biomass.

distribute in China under the Green Aid Plan (GAP). The issues 15

Clean Coal Technologies in Japan

1A3. Internal Circulating Fluidize Bed Combustion Technology (ICFBC) In charge of research and development: Center for Coal Utilization, Japan; Ebara Corporation; Idemitsu Kosan Co., Ltd. Project type: Coal Production and Utilization Technology Promotion Grant Period: 1987-1993 Outline of technology

1.Features The ICFBC has basic functions described below.

3)Low pollution

I.Uniform temperature in fluidize bed owing to the swirling flow of

The emissions of pollutants such as NOx and SOx are

sand.

significantly reduced without adding special environmental

II.Easy discharge of noncombustible owing to vigorous

material.

movement of sand.

proceeds mainly in the furnace. However, ICFBC does not have

III.Available in controlling the temperature of fluidized bed by

heat transfer tube in the fluidizing section so that the boiler raises

adjusting the heat recovery from fluidized bed.

no wear problem on the heat transfer tube in bed. Thus, the

Based on the basic functions, ICFBC has features described

fluidizing material of ICFBC does not need to use soft limestone,

below.

and it can use silica sand. As a result, ICFBC needs minimum

1)Adoption of various fuels

quantity of limestone as the intrafurnace desulfurization agent.

Similar with CFBC described before, the applicable fuel for

The desulfurization efficiency of ICFBC becomes close to 90% at

ICFBC includes not only fossil fuel such as high grade coal, oil,

Ca/S molar ratio of around 2, though the efficiency depends on

and gas, but also low grade coal, biomass, sludge, waste

the coal grade, applied limestone, and temperature of fluidized

plastics, and waste tire.

bed. The denitration is conducted by two-stage combustion: the

2)Control of bed temperature

reducing combustion at the fluidized bed section; and the

Since the overall heat transfer coefficient varies almost linearly

oxidizing combustion at the freeboard section.

with the variations in air flow rate in the heat recovery chamber,

carbon coming from the boiler is collected by the high

the quantity of recovering heat is easily controlled through the

temperature cyclone installed at exit of the boiler, which collected

control of air flow rate.

unburnt carbon is recycled to the boiler to increase the

In addition, control of the quantity of

For the fluidizing bed boiler, the desulfurization

The unburnt

recovering heat controls the temperature of fluidized bed. Since

denitration efficiency.

the control of recovering heat is performed solely by varying the

4)Space saving and maintenance ability

air flow rate, the load control is very simple, which is a

Similar with the above-described CFBC, the ICFBC does not

strongpoint of ICFBC.

need separate units for desulfurization, denitration, and fuel finely crushing, therefore, the ICFBC facilities are space saving one and have high maintenance ability owing to the fewer sections of trouble-occurrence.

2.Outline of technology Figure 1 shows outline of ICFBC. The technology uses silica sand as the fluidizing material. The fluidized bed is divided into

Freeboard

the main combustion chamber and the heat recovery chamber by

Primary combustion chamber

a tilted partition to create swirling flow inside the main combustion chamber and the circulation flow between the main combustion chamber and the heat recovery chamber.

A

circulation flow is created to return the unburnt char and unreacted limestone coming from the cyclone at exit of the boiler

Heat recovery chamber

to the boiler. 1)The swirling flow in the main combustion chamber is created by dividing the window box in the main combustion chamber to three sections, and by forming a weak fluidized bed (moving bed) at the center section introducing small amount of air, while forming rigorous fluidized bed at both end-sections introducing large amount of air.

As a result, the center section of the main

combustion chamber forms a slow downward moving bed, and the fluidizing material which is vigorously blown up from both ends sediments at the center section, and then ascends at both

Fig. 1 Outline of ICFBC

end-sections, thus creating the swirling flow. 16

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

2)The circulation flow between the main combustion chamber

3.Study site and use field

and the heat recovery chamber is created by the movement

Examples of coal fired ICFBC include: Chingtao, EBARA CORP.

described below.

(10 t/h); Jiangsan in China (35 t/h); and Nakoso, Nippon Paper

A portion of the fluidizing material which is

vigorously blown up at both end-sections in the main combustion

Industries Co. (104 t/h).

chamber turns the flow direction toward the heat recovery

waste as the fuel include: Motomachi, Toyota Motor Corp. (70

chamber at above the tilted partition. The heat recovery chamber

t/h); Tochigi, Bridgestone Corp. (27 t/h); Fuji, Daishowa Paper

forms mild fluidized bed (downward moving bed) by the

Mfg. Co., Ltd. (62 t/h); Amaki, Bridgestone Corp. (7.2 t/h); and

circulation bed air injected from under the chamber. Accordingly,

Akita, Tohoku Paper Mfg. Co., Ltd. (61.6 t/h). An example of RDF

the fluidizing material circulates from the main combustion

fuel ICFBC is Shizuoka, Chugai Pharmaceutical Co., Ltd. (3.7

chamber to the heat recovery chamber, and again to the main

t/h).

Examples of ICFBC using industrial

combustion chamber from the lower part of the heat recovery chamber. Since the heat recovery chamber is equipped with heat transfer tubes, the circulation flow recovers the thermal energy in the main combustion chamber.

4.Development period

3)The circulation flow coming from the cyclone at exit of the boiler

The ICFBC was developed in 1987, and was further

passes through the cyclone or other means to collect unburnt

developed and validated as the low pollution, small scale, and

char, emitted fluidizing material, and unreacted limestone, and

high efficiency fluidized bed boiler for multiple coal grades in

then returns to the main combustion chamber or the heat

the "Study of Fluidized Bed Combustion Technology" of the

recovery chamber using screw conveyer, pneumatic conveyer, or

Coal Utilization Technology Promotion Grant project of the

other means.

Ministry of the International Trade and Industry over six years

The circulation flow is extremely effective to

increase combustion efficiency, to decrease NOx generation, and

from 1988 to 1993.

to increase desulfurization efficiency.

5.Progress and result of the development Although ICFBC was developed initially to use industrial waste giving high calorific value, it was improved to use solid fuel with a high calorlfic value and has been developed as a coal-fired boiler. For China having abundant coal reserves, a boiler plant was constructed at Chingtao as the production base in China. Recently in Japan, wood-base biomass is used as the fuel in some cases.

However, further reduction in investment is

required to propagate the technology to Southeast Asia and other areas rich in the biomass resource and low grade coal.

Photo 1 Overview of ICFBC

Steam Boiler Drum

Dry Coal

Stack Dry Feed System

Coal Bunker

Limestone Pulverized Coal Slurry Feed System Air Compressor

CWP Mixing System

Air Heater Depressurizing Unit

PICFB

Crusher

Hot gas Filter

IDF Steam

Bag Filter

Waste Heat Boiler (Gas Cooier)

CWP Pump

Ash Cooling Pipe

Pressure Vessel

Boiler Water Circulation Pump Hot Blast Generator

Deashing System

Pneumatic Ash Transport System

Fig. 2 Flowchart of PICFBC hot model test plant 17

Ash

Clean Coal Technologies in Japan

1A4. Pressurized Internal Circulating Fluidized Bed Combustion Technology (PICFBC) In charge of research and development: Center for Coal Utilization, Japan; Ebara Corporation Project type: Coal Production and Utilization Technology Promotion Grant Period: 1992-1998

Outline of technology

1.Outline The basic technology is the technology of internal circulating fluidized bed boiler (ICFBC) described in preceding section. The

PICFBC mounts ICFBC in a pressure vessel.

2.Features The pressurized internal circulating fluidized bed boiler (PICFBC) is structured applying the circulation flow technology of abovedescribed ICFBC. Accordingly, the load control is available without varying the height of fluidized bed. In addition, cooling of combustion gas is avoided because the intrabed heat transfer tubes do not expose on the bed during load controlling action, which minimizes the generation of CO2 and eases the maintaining temperature at inlet of gas turbine. Since the wear problem of

heat transfer tube in bed is decreased, silica sand can be used as fluidizing material, and the amount of limestone can be minimized to a necessary level for the intrafurnace desulfurization, thus suppressing the generation of ash. Furthermore, the main combustion chamber has no intrabed heat transfer tube so that the problem of interference of intrabed heat transfer tube against the particle movement does not occur, which prevents the generation of agglomeration.(the solidification of melted medium)

3.Outline of technology chamber and the heat recovery chamber. Figure 2 (P.17) shows the rough flowchart of the hot model test plant at Sodegaura. The coal feed unit has two lines: the lock hopper system which feeds lump coal ; and the CWP(Coal Water Pellet) mixing system which feeds coal as slurry mixed with water. The dust of combustion gas is removed by the high temperature bag filter structured by ceramics filter. The lock hopper system technology is applied to develop the pressurized two-stage gasification technology.

Figure 1 shows schematic drawing of PICFBC. The cylindrical pressure vessel contains the cylindrical ICFBC. Similar with ICFBC, silica sand is used as the

Fig. 1 Schematic drawing of PICFBC

fluidizing material. The fluidized bed is divided into the main combustion chamber and the heat recovery chamber by the tilted partition. The swirling flow is created in the main combustion chamber, and the circulation flow is created between the main combustion

4.Study site and use field The PICFBC hot model test was carried out at a site next to the Coal Research Laboratory (Nakasode, Sodegaura City, Chiba) of Idemitsu Kosan Co., Ltd. Applicable fields include the steam turbine generator using the generated steam and the gas turbine generator using the combustion flue gas. Therefore, IGCC at coal fired thermal power plant is a candidate. Photograph 1 shows the installed hot model of PICFB 4 MWth. Photograph 2 shows the overview of the pressurized two-stage gasification plant (30 t/d of waste plastics throughput) in a demonstration test at a site next to the Ube Ammonia plant. The pressurized two-stage gasification technology has a use field of production of hydrogen which is used for ammonia synthesis and fuel cell power

generation. The pressurized two-stage gasification technology is in operation as a commercial plant (195 t/d of waste plastics throughput) at Kawasaki of Showa Denko K.K. since 2003.

Photo 1 Overview of PICFBC

Photo 2 Overview of pressurized two-stage gasification plant

5.Period of development The PICFBC hot model test was carried out from 1992 to 1997. The hot model test was conducted jointly with The Center for Coal Utilization,Japan, as the Coal Utilization Technology Promotion Grant project of the Ministry of International Trade and Industry. The test operation began from December

1996. The pressurized two-stage gasification technology was developed jointly with Ube Industries, Ltd. The demonstration operation of the plant (30 t/d of waste plastics throughput) began from January 2000, and the commercial operation began from January 2001.

6.Progress and issue of the study As the coal fired PICFBC, the study proceeded up to the hot model test at Sodegaura. The technology, however, has developed to the pressurized two-stage gasification technology in which the thermal load and the lock hopper system in the

pressurized fluidized bed are applied. The issues of pressurized system include the improvement in the reliability of lock hopper system in the fuel charge line and the measures to low temperature corrosion. 18

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

1A5. Coal Partial Combustor Technology (CPC) In charge of research and development: Center for Coal Utilization, Japan; Kawasaki Heavy Industries, Ltd.; Kawasaki Steel Corp.; Chubu Electric Power Co., Inc.; and Electric Power Development Co., Ltd. Project type: Coal Production and Utilization Technology Promotion Grant Period: 1978-1986 (9 years)

Outline of technology

1.Background and outline of technology Owing to the abundant reserves and wide distribution of

Coal Partial Combustor (CPC) is a furnace where coal and air are

production countries, coal has high supply stability, and is

injected at high speed into a swirling melting furnace in tangential

positioned as an important energy source in the future.

direction, thus conducting partial combustion (gasification) of coal

Compared with other fuels such as oil and gas, however, coal

under the condition of high temperature, heavy load, and strong

contains large amount of ash and nitrogen, thus has many issues

reducing atmosphere, and after most of ash in coal is melted and

in use, including facility trouble caused by ash and significant

separated to remove, the produced fuel gas is subjected to

increase in NOx emissions. Furthermore, global warming issue

secondary combustion.

has become international concern in recent years, which raises

gasification combustion in boiler or gas turbine to utilize coal at

an urgent requirement of development of technology to reduce

high efficiency and environmentally compatible state. The CPC

emissions of CO2 which is one of the main cause materials of

has the normal pressure CPC technology and pressurized CPC

global warming.

technology.

In this respect, the world waits for the

That is, CPC is a technology of coal

The former conducts very low NOx combustion

development of technology of high efficient and environmentally

through the gasification in boiler, or generates low calorific gas at

compatible utilization of coal which generates large amount of

normal pressure.

CO2 per calorific value.

generation by pressuring the gas on the basis of the developed

The latter achieves high efficiency power

technology of the former, and by combining it with gas turbine.

2.Normal pressure coal partial combustor technology Boilers of fusion and combustion type aiming at volume-reduction Preheating burner

and detoxication of ash discharged from boiler and at use of difficult-to-combust coal were constructed and are operating in

Preliminary

large number centering on Western countries. The conventional

combustor

Baffle

Secondary combustor

melting and combustion method has advantages of high combustion efficiency and recovery of ash as nontoxic molten slag.

Combustion air

However, the method has drawback of large NOx

emissions caused by high temperature combustion.

High temperature combustion gas

Pulverized coal

Responding to the issue, our technology development focused on the development of coal partial combustor system aiming to simultaneously achieve the fusion to remove ash from coal and the low NOx combustion. The system adopted direct mount of CPC to the side wall of boiler, and the combustible gas generated in CPC is directly charged to the boiler furnace, where the gas is completely combusted with charged air.

Molten slag

As medium to small coal fired boilers, CPC can significantly Fig.1 Schematic drawing of normal pressure coal partial combustor (CPC) boiler

reduce NOx emissions while maintaining the compactness of boiler similar with the scale of oil fired boiler, and can recover all the coal ash as molten slag. The right figure shows schematic drawing of the normal pressure CPC boiler.

19

Clean Coal Technologies in Japan

3.Pressurized coal partial combustor technology On the basis of the result of normal pressure CPC development,

The figure below shows rough flow chart of the pressurized CPC

the development of pressurized CPC technology began aiming at

pilot plant having 25 t/d of coal gasification capacity (operating at

the development of high efficiency power generation system by

oxygen 21%). The pilot plant ran the coal gas generation test

pressurizing CPC and combining it with gas turbine.

using CPC under pressure of 20 ata which can be applied to gas turbine. The test proved the effectiveness of the pressurized PCP.

Pressurized pulverized coal feeder

Kerosene tank Gas cooler

Ceramic filter

Gas incinerator Pulverized coal production unit

Denitration unit Flux feeder

Char hopper

Liquid oxygen tank

Cooler

Primary air compressor Slag tank Char feeder

Air compressor

Desulfurization unit

Liquid nitrogen tank Fig.2 Rough flow chart of pressurized CPC pilot plant

4.Issue and feasibility of practical application The normal pressure CPC technology has already been brought into practical applications as low NOx emission technology in swirling melting furnaces of municipal waste gasification melting furnaces and in very low NOx boiler for heavy oil combustion. Also the normal CPC technology is in the development stage of coal ash melting type low NOx boiler.

The pressurized CPC

technology is in the stage of completion of pilot plant test, and is in the research and development stage in private sector aiming at practical use of the technology. These basic technologies have also been integrated with the development of biomass gasification gas turbine power generation technology.

Photo 1 Total view of pilot plant

20

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

1A6. Pressurized Fluidized Bed Combustion Technology (PFBC) In charge of research and development: Center for Coal Utilization, Japan; and Electric Power Development Co., Ltd. Project type: Coal Production and Utilization Technology Promotion Grant Period: 1989-1999 (11 years)

Outline of technology

1.Background and process outline (1)The research and development of pressurized fluidized bed

(2)Outline of facilities

combined power generation technology was conducted at

Plant output 71.0 MWe

Wakamatsu

Pressurized fluidized bed combustion once-through boiler (ABB-

Coal

Utilization

Research

Center

(present

IHI production)

Wakamatsu Research Institute) of Electric Power Development Co., Ltd. using the 71 MWePFBC Plant, which was the first PFBC

Bubbling type pressurized fluidized bed, Coal water paste

plant in Japan. The test plant was the first plant in the world in

(70-75%) injection type

terms of full-scale adoption of ceramic tube filter (CTF) which is

Combustion temperature 860 C

able to collect dust from high temperature and high pressure gas

Combustion air pressure 1 MPa

O

at high performance. Outline of the process is shown in Fig. 1.

Ammonia water injection (Non-catalytic denitration) Ash recirculation cyclone

Ceramic tube filter (CTF)

Main steam / Reheated steam 593 C/593 C Steam turbine O

O

Air Gas turbine

CTF ash Fuel nozzle

Intercooler

Condenser

Coal, limestone, water

Denitration unit

Pressure vessel Bottom ash (BM)

Deaerator

Water supply pump

Fuel slurry pump Water supply heater

Economizer

Fig. 1 Outline of PFBC process

21

Clean Coal Technologies in Japan

2.Development object and technology to be developed Object of PFBC technology development

desulfurization unit.

(1) Increase in efficiency through the combined power generation

Result of PFBC technology development

utilizing the pressurized fluidized bed combustion conditions:

(1) Gross efficiency of 43% level was achieved by increased

(gross efficiency of 43%)

efficiency through the combined power generation utilizing the

(2) Providing advanced environmental characteristics including:

pressurized fluidized bed combustion conditions.(2) SOx level of

SOx reduction through the in-bed desulfurization; NOx reduction

about 5 ppm through the in-bed desulfurization, NOx level of

through the low temperature combustion (about 860 C); Dust

about 100 ppm through the low temperature combustion (about

reduction by CTF; and CO2 reduction by increased efficiency.

860 C), and the dust level of less than 1 mg/Nm3 or less by CTF

O

O

(3) Space saving of plant through the compact design of boiler adopting

pressurized

condition

and

the

elimination

was achieved.

of

3.Progress and result of the development Detail design of the facilities began in FY1990, construction

modified to adopt the ash-recycle system.

began in April 1992, and facilities installation began in October

demonstration operation was conducted from August 1998 to

1992.

Test operation began in April 1993, coal combustion

December 1999. The cumulative operating time of PFBC was

began in September 1993, and 100% load was achieved in

16,137 hours including 10,981 hours in Phase 1 and 5,156 hours

January 1994.

in Phase 2. In particular, Phase 2 achieved continuous operation

The two-stage cyclone system passed the

Phase 2

examination before entering operation in September 1994, and

of 1,508 hours.

the CTF system passed the examination before operation in

findings were acquired in terms of performance and reliability.

December 1994.

These results have already been applied to the construction of

Phase 1 demonstration operation was

conducted until December 1997.

Through the operation, valuable data and

commercial facilities of the three electric power companies.

After that, the plant was

PFBC development schedule FY1990

FY1991

FY1992

FY1993

FY1994

FY1995

FY1996

FY1997

Basic and detail design Construction start

FY1998

Integration

Construction of demonstration plant

FY1999

Final assessment

FY1989

Interim assessment

Fiscal year Item

Test operation and adjustment Demonstration operation Phase 1

Test operation Modification

Modification

Demonstration operation Phase 2

Test operation

4.Issue and feasibility of practical application The feature of PFBC is adaptability to urban-operation owing to

materials and waste, utilizing the superior combustion

the excellent environment-compatible characteristics including 10

performance; the in-bed desulfurization; the combination with

ppm or lower SOx emissions, 10 ppm of NOx emissions, and 1

catalytic or non-catalytic denitration; and the high temperature

mg/Nm3 or lower dust concentration, and to the reduced space

and high performance dust collection by CTF. The issue is to

of plant owing to the elimination of desulfurization unit. These

improve economy by fully utilizing these characteristics of the

advantageous characteristics are obtained by: the diversification

system and by selecting adequate location.

of applicable fuels such as difficult-to-combust or low grade

Reference

Yamada et al.: "Coal Combustion Power Generation Technology", Bulletin of the Japan Institute of Energy, Vol.82, No.11, November, pp822-829, (2003)

22

Part2 Outline of CCT Coal Fired Power Generation Technologies (Combustion Technologies)

1A7. Advanced Pressurized Fluidized Bed Combustion Technology (A-PFBC) In charge of research and development: Center for Coal Utilization, Japan; Electric Power Development Co., Ltd.; Chubu Electric Power Co., Inc.; and Mitsubishi Heavy Industries, Ltd. Project type: Coal Production and Utilization Technology Promotion Grant Period: 1996-2002

Outline of technology

1.Outline The development of coal utilization high efficiency power

about 850 C to about 1,350 C), and to recover high temperature

generation technology is an urgent issue from the viewpoints of

steam, thus to attain higher efficiency of power generation (about

reduction in greenhouse gases and of resource saving.

46% of net efficiency; about 40% for the current coal fired power

Technology A-PFBC is a further advanced technology of PFBC

plants) by the combination of PFBC with the fluidized bed

(pressurized fluidized bed combustion). That is, the development

gasification technology.

O

O

aimed to increase the temperature at inlet of gas turbine, (from

Synthesis gas cooler Limestone

Desulfurizer

Cyclone

Ceramic Filer

Partial Gasifier Combustor Ash

Gas turbine Air Char Coal Flue gas

Gas Flow Air Ash

Steam Flow

Steam turbine

Oxdizer (PFBC)

Fig. 1 Flowchart of A-PFBC combined power generation system

2.Development object and technology to be developed (1) High efficiency power generation [Net efficiency: about 46%]

(2) Mild gasification condition [Carbon conversion: about 85%]

- Increase of gas turbine inlet temperature

- 100% gasification in the partial gasifier by the combination with

(from about 850 C to about 1,350 C)

the oxdizer (perfect oxidizing atmosphere)

- Recovery of high temperature steam

(3) Utilization of results of related technologies

(High temperature steam recovery at the synthesis gas cooler

- PFBC technology

applying the high temperature desulfurizer)

- Various coal gasification technologies

O

O

23

Clean Coal Technologies in Japan

3.Progress and result of the development Aiming at the practical application of the above-described system, the study team installed a small scale process development unit (refer to the photograph of total view of PDU) at Wakamatsu Research Inditnte (Kita Kyushu City) of Electric Power Development Co., Ltd. The PDU test operation began in July 2001. By the end of FY2002, the cumulative gasification operation time reached 1,200 hours, and the continuous gasification operation reached 190 hours.

Desulfurizer

The PDU test

confirmed the three-reactors link operation, which is an objective of the system validation, and acquired characteristics Partial gasifier

of each reactors, thus confirmed the data necessary for scale up.

Oxidizer

The development has an issue of validation of total system combined with gas turbine at larger scale, or pilot plant scale. (1) Outline of the test of the process development unit (PDU) [Object of the test] For the system of three-reactors combination (oxidizer, partial gasifier, and desulfurizer), (refer to Fig. 2), the acquisition of

Fig. 2 PDU: LAyout of three reactors

reaction characteristics and operation characteristics, and the validation of the process are conducted to acquire the scale up data. - Validation of the three-reactor link process - Confirmation of performance of individual facilities (oxidation, gasification, desulfurization, etc.) - Confirmation of basic operability - Acquisition of various characteristics, acquisition of scale up data, etc. [Outline of facilities] With the main object of validation of the system, the plant contains limited range of facilities including the main three reactors, (coal treated scale: 15 t/d). Gas turbine system and steam turbine system are not installed in PDU because their performance is available from similar systems. Fig.3 PDU: Total view

A-PFBC development schedule Fiscal year Item

FY1996

FY1997

FY1998

FY1999

FY2000

FY2001

FY2002

(1) Research plan, technology study

(2) Elementary test and F/S Installation completion Design, manufacturing, and installation

(3) PDU test (15 t/d)

(4) Process evaluation

Reference

Preprint for the 13th Coal Utilization Technology Congress, "A-PFBC"; sponsored by Center for Coal Utilization

24

Test operation

Part2 Outline of CCT Coal Fired Power Generation Technologies (Gasification Technologies)

1B1. Hydrogen-from-Coal Process (HYCOL) In charge of research and development: HYCOL Association [Idemitsu Kosan Co., Ltd.; Osaka Gas Co., Ltd.; Electric Power Development Co., Ltd.; Tokyo Gas Co., Ltd.; Toho Gas Co., Ltd.; Nikko Kyoseki Co., Ltd.; The Japan Steel Works, Ltd.; Hitachi Ltd.; and Mitsui Coal Liquefaction Co., Ltd.] Contract project of NEDO Project type: Contract project of NEDO

Outline of technology

1. Background and process outline The technology is a gasification technology utilizing spouted bed

efficiency is attained, and heavy load gasification is performed.

in which pulverized coal with oxygen under high temperature and

(2)The slag self-coating technology for the water cooled tubes

high pressure condition. Trough the gasifier, we can obtain the

was developed. By the technology it is realized to prolong the life

medium calorific value gas that is rich in hydrogen and carbon

of the tubes and to have reliability for the gasifier.

monoxide. The technology is called the "HYCOL process".

(3)The swirling gas flow distributor was developed and adopted

Through the shift reaction, the gas yields carbon monoxide and

as the technology to easily and uniformly distribute coal to many burners.

changes steam to carbon dioxide and hydrogen. After separating

(4)Ash in coal is melted in the gasification furnace. The melting

the carbon monoxide and carbon dioxide, the gas is purified to become

ash is discharged through the slug hole located on the hearth at

high purity hydrogen.

the furnece. As the result of the swirling gas flow, the high

Hydrogen is used in oil refinery and chemical industry, further in

temperature of the slag hole is maintained, and the smooth

coal liquefaction process. On the other hand, the obtained gas

flowdown of the slag is secured.

containing carbon monoxide is expected to be used widely as a

(5)The unreacted char discharged from the gasification furnace

raw material of chemical synthetic products, fuel for fuel cell, and

accompanied with gas is separated by cyclone or other device to

fuel in various industries.

recycle to the gasification furnace in high temperature and high

The HYCOL process has the features described below.

pressure state, thus ensuring complete reaction.

(1)The process uses a dry-feed type one-chamber and two-stage

(6)Ash in coal is recovered as slag which does no elute toxic

swirling spouted bed gasification furnace. Pulverized coal which

ingredients. Together with the advantage of ready recovery of

is pressurized in a lock hopper is fed, in dry state, to the

sulfur-components and nitrogen components in a form of H2S

gasification furnace via burners in swirling mode. The burners

and NH3, respectively, the ash recovery significantly reduces the

are arranged by four of them in each stage. The oxygen feed

environmental loads.

and the coalification rate at upper stage and lower stage are

Coal to have lower melting point of ash or to have smaller fuel

separately controlled.

ratio (fixed carbon to volatile matter) is more easily gasified.

Through the operation, high thermal

2. Progress and result of the development

3.Issue and feasibility of practical application

HYCOL association (structured by above-listed nine private

The development of coal gasification fuel cell system (IGFC) for

companies) contracted the research and development agreement

power generation utilizing HYCOL technology has begun from

on the pilot plant under supported by NEDO. On the other hand,

1995, (EAGLE Project).

five private companies (Hitachi Ltd., Babcock-Hitachi K.K., Asahi Glass Co., Ltd., Shinagawa Refractories Co., Ltd., and NGK Spark Plug Co., Ltd.) contracted the basic study on the structure of the furnace and on the materials with NEDO. For establishing the process, the pilot plant was constructed at Sodegaura, Chiba. The operational study of the pilot plant was conducted from 1991 to 1994.

The performance target was

achieved, and the world’s top gasification furnace technology was established.

25

Clean Coal Technologies in Japan

Water-washing process

Gasification process

Gasification furnace

Water-washing column

Lock hopper

Coal

Pulverized coal apparatus

Product gas firing process

Boiler

Pretreatment process

Incineration Waste furnace heat boiler Distributor Desulfurization unit

Lock hopper

Air heater

Recycle gas compressor Ash treatment process

Fig.1 Flowchart of pilot plant

Specification and target performance of pilot plant Coal throughput

max. 50 ton/day

Gasification agent

Oxygen

Gasification pressure

30 kg/cm2(G)

Gasification temperature

1,500-1,800 C

O2/Coal

0.8-0.9 (weight ratio)

Product gas volume

about 91 kNm3/day

O

Gas composition

CO

61%

(design)

H2

31%

CO2

3%

Carbon conversion

98% or more

Cool gas efficiency

78 % or more

26

Part2 Outline of CCT Coal Fired Power Generation Technologies (Gasification Technologies)

1B2. Integrated Coal Gasification Combined Cycle (IGCC) In charge of research and development: Clean Coal Power R&D Co., Ltd. (Until 2000, the study has been conducted as a joint activity of power companies led by The Tokyo Electric Power Co., Inc.) Project type: Grant for "Demonstration of Integrated Coal Gasification Combined Cycle Power Generation "/ the Agency of Natural Resources and Energy of the Ministry of Economy, Trade and Industry Period: 1999-2009 Outline of technology

1. Outline and object of IGCC demonstration test Integrated Coal Gasification high

efficiency

1. Increase in thermal efficiency---Compared with conventional

Syngas

Combined Cycle (IGCC) is a

pulverized coal fired power plants, IGCC can increase net

Unreacted coal (char)

thermal efficiency by about 20% for commercial plant.

power

generation technology which gasifies coal to be used as the Reductor (gasification chamber)

fuel for gas turbine. Japanese power companies promoted research and development of

Char recovery unit

2. Better environmental characteristics---Owing to the increase in

Char

generated power are reduced. In addition, amount of CO2

thermal efficiency, the emissions of SOx, NOx, and dust per emissions is reduced generation process.

Coal

IGCC technology applying the Nakoso pilot plant (PP) type gasifier 1,2)

as

technology3).

the

3. Increase in applicable grades of coal---IGCC can use coal, Coal Air

core

Combustor (combustion chamber)

having low ash melting points, which are difficult to be used in

Air

conventional pulverized coal fired power plants.

Molten slag Water

power plant.

Slag hopper

4. Increase in applicable fields of ash---Since IGCC discharges

oxygen-enriched air blown, two

As a result,

IGCC widens the variety of coal grades applicable in coal fired

The PP type

gasifier applies dry coal fed, pressurized

to the level of heavy oil fired power

coal ash in a form of glassy molten slag, the ash is expected to

stage Molten slag

entrained beds, as shown in

be effectively used as materials for civil works.

Fig. 1 Nakoso PP type gasifier

Figure 1, which is expected to

5. Reduction of water consumption---Owing to the direct

give higher efficiency than preceding gasifiers in abroad.

desulfurization of generated gas, IGCC does not need the flue

On the basis of the study results, the IGCC demonstration test

gas desulfurization unit which consumes large amount of water.

project was started

Accordingly, IGCC significantly reduces the water consumption

with the aims to validate the reliability,

compared with conventional pulverized coal fired power plant.

operability, maintenance ability, and profitability of IGCC, and to confirm the feasibility of coal fired IGCC commercial plant. Compared with conventional pulverized coal fired power plants , IGCC has many advantages as described below. 2.Specification and object of IGCC demonstration plant Figure 2 shows the flow diagram of the IGCC demonstration

MW, 1700 t/d of coal feed) is about a half of commercial plant.

plant. Table 1 shows main specifications and target values of the

The gasifier is of the Nakoso PP type. Wet type gas clean up

plant.

system with MDEA is adopted . The gas turbine is the 1200OC-

Figure 3 shows conceptional drawing of IGCC

demonstration plant. The scale of IGCC demonstration plant(250 Coal Gasifier

Heat exchanger

class gas turbine corresponding to the output of 250 MW.

Gas cleanup Char recovery unit Combustor Gas turbine

Table 1 Main specifications and target values of IGCC demonstration plant Air

Output Coal feed rate

Steam turbine

250 MW class about 1,700 t/d Gasifier

Type

Waste heat recovery boiler

Nitrogen

Oxygen

Gas cleanup Gas turbine Target thermal Gross efficiency efficiency (LHV) net efficiency Environmental SOx emission concentration characteristic NOx emission concentration (target value) Dust emission concentration

Stack

Gasifier Heat exchanger Air separator

Fig.2 Flow diagram of IGCC demonstration plant

27

Dry coal fed, air blown, pressurized two stage spouting beds

Wet gas cleanup (MDEA) + Gypsum recovery 1200 OC - class 48% 42% 8 ppm (O2 16% conversion) 5 ppm (O2 16% conversion) 4 mg/Nm3 (O2 16% conversion)

Clean Coal Technologies in Japan

3.Organization for executing the IGCC demonstration test The IGCC demonstration test is conducted by Clean Coal Power R&D Co., Ltd. (CCP R&D Co., Ltd.) which was established by

Gasification train

nine power companies and Electric Power Development Co., Ltd.

Combined cycle block

As for the project cost, 30% of the cost is national aid (Ministry of Economy, Trade and Industry), and 70% is shared by total eleven corporations:

nine

power

companies,

Electric

Power

Development Co., Ltd., and Central Research Institute of Electric Power Industry. (Refer to Fig. 4.) METI 30% subsidy Joint project agreement 70% contribution

Gas cleanup train

Nine power companies Electric Power Development Co., Ltd.

CCP R&D Co., Ltd. Personnel

Central Research Institute of Electric Power Industry

Fig. 4 Schem of demonstration project

Fig. 3 Conceptional drawing of IGCC demonstration plant

4.Schedule and progress Table 2 shows the schedule of demonstration project.

test are scheduled to start from second half period of FY2007 for

As of

about three years.

January 2004, the detail design and the environmental assessment are in progress. Plant operation and demonstration Fiscal year

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Preliminary validation test Design of demonstration plant

Establishment of CCP R&D Co., Ltd

Environmental assessment Construction of demonstration plant Plant operation and demonstration test Table 2 Schedule of IGCC demonstration project

5.Activities until now The pilot plant test (200 t/d of coal feed) which is the preliminary

Nakoso Power Plant of Joban Joint Power Co., Ltd.

stage of the demonstration test was carried out through a period

Executed site of pilot plant test; Planned site for demonstration test

from 1986 to 1996 at Nakoso Power Plant of Joban Joint Power Co., Ltd. in Iwaki City, Fukushima, (Fig. 5). The pilot plant test was conducted jointly by nine power companies, Electric Power Development Co., Ltd., and Central Research Institute of Electric Power Industry, as a contracted project of NEDO. The pilot plant test of 4,770 hours including 789 hours of continuous operation test proved the practical applicability of the IGCC technology3). Based on the success of the pilot plant test, the demonstration test reflected the optimum system which was selected by feasibility study given by NEDO. Through various investigations, the demonstration test will be conducted at the site of pilot plant in Nakoso Power Plant of Joban Joint Power Co., Ltd. again.

Fig. 5 Planned site for demonstration test. (Iwaki City, Fukushima, site for pilot scale test)

References

1) Shozo Kaneko,et.al., "250MW AIR BLOWN IGCC DEMONSTRATION PLANT PROJECT", Proceeding of the ICOPE-03(2003),3-pp163~167 2) Christopher Higman,Maarten van der Burgt,"Gasifaication"(2003), pp126-128 3) Narimitsu Araki and Yoshiharu Hanai: Bulletin of Japan Energy, 75-9, (1996) pp839-850 28

Part2 Outline of CCT Coal Fired Power Generation Technologies (Gasification Technologies)

1B3. Coal Energy Application for Gas, Liquid and Electricity (EAGLE) In charge of research and development: New Energy and Industrial Technology Development Organization; Electric Power Development Co.,Ltd.; The Center for Coal Utilization, Japan; and Babcock Hitachi K.K. Project type: Coal Production and Utilization Technology Promotion Grant; and Grant for the Development of Advanced Technology for Generation of Fuel Gas for Fuel Cell Development Period: 1995-2006 (12 years)

Outline of technology

1.1. Summary of technology The multi-purpose coal gas production technology development

blown, single-chamber, two-stage swirling flow gasifier that permits

(EAGLE) mentioned here aims, in an attempt to reduce

the high-efficiency production of synthetic gas (CO+H2).

environmental load, (particularly, to decrease the amount of

application of this gasifier and its combination with gas turbines,

greenhouse gas generated) at establishing a coal gasification

steam turbines, and fuel cells further permit high-efficiency power

technology which is widely applicable to chemical materials,

generation [Integrated Coal Gasification Fuel Cell Combined Cycle

hydrogen production, synthetic liquid fuel, electric power, and other

(IGFC)], which will optimistically generate 30% less CO2 emissions

purposes through the development of the most advanced oxygen-

than that of existing thermal power plants.

The

2.Development targets and technology to be developed When applying coal gasification gas for IGFC and synthetic

Target item

fuel/hydrogen/chemical fertilizer production, it is necessary to set targets to meet the refinement level required by fuel cells as well as the catalyst since impurities contained in the gas such as sulfur compounds may poison fuel cells and the reactor catalyst, thereby weakening their performance. Although not so much has

Coal gasification performance Continuous operation performance

1,000 hours or more

been reported, even globally, about the effects of fuel cell-

Adaptability to various grades coal

poisoning materials (including halogen) in particular, the EAGLE

Capability to scale up

Project has established development targets as listed in the table on the right with reference to DOE, MCFC Association, and other reports.

Target of development Gas calorific value: 10,000 kJ/Nm3 or more Carbon conversionrate: 98% or more Cold gas efficiency: 78% or more Gasification pressure: 2.5 Mpa

Gas purification performance

Acquisition of gasification data for 5 or more grades coal having different properties from each other Acquisition of data for scale up aiming at about 10 fold of scale up Sulfur compounds: 1 ppm or less (precise desulfurizer outlet) Halogens: 1 ppm or less (precise desulfurizer outlet) Ammonia: 1 ppm or less (precise desulfurizer outlet) Dust: 1 mg/Nm3 or less (precise desulfurizer outlet)

Coal Gasification Facilities

Gas Clean-up Facilities

Precise desulfurizer Gasifier

SGC MDEA Regenerator

Pulverized coal COS converter

Acid Gas Furnace

Filter

Primary Scrubber

Seconday Scrubber

Limestone Absorber

MDEA Absorber

Char Slag

Incinerator

Compressor

Rectifier

HRSG

Air

Air separator

Stack

Gas turbine facility

Fig.1 Flowchart of EAGLE 150 t/d pilot plant

29

Clean Coal Technologies in Japan

3.The Process and its Prograss A joint team from New Energy and Industrial Technology

the Technology Development Center of Electric Power

Development Organization and Electric Power Development Co.,

Development Co., Ltd., (refer to photograph).

Ltd. among others promotes the project. The pilot plant (150 t/d)

undergoing test operations.

The plant is

was constructed on the grounds of the Wakamatsu Laboratory at EAGLE development schedule Fiscal year

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Item

Final assessment

F/S Test

Primary test

Design

Design of pilot plant Construction of pilot plant

Construction

Test operation

Test operation

Analysis

4.Future issues and the feasibility of practical application Through the acquisition of basic characteristics and performance,

analysis of issues related to improved gasification performance

research

and to long-term operation.

and

development

is

scheduled

to

acquire

characteristics of various grade coal, to acquire, analyze, and

With respect to practical application and commercialization,

evaluate data, and to establish operational control technology

active promotion will be enhanced based on the results of the

with stepwise confirmation of reliability and identification and

testing, research, and development.

Syngascooler

Gasifier

Gas clean-up

Filter Coal Nitrogen

Air

Oxygen

HRSG Expansion turbine Compressor Steam turbine Heat recovery boiler Circulation blower

Circulation blower

Gas turbine

Air

Catalyst burner

Photo 1 Total view of the pilot test facilities

Fig.2 IGFC system

Reference

1) Masao Sotooka: Coal Gasification Technology (II) - Coal Energy Application for Gas, Liquid and Electricity (EAGLE), The Japan Institute of Energy, Vol.82, No.11, November, pp836-840, (2003) 30

Part2 Outline of CCT Iron Making and General Industry Technologies (Iron Making Technologies)

2A1. The Formed-Coke making Process (FCP) in research charge of research and development InMembers charge of and development: Center for Coal Utilization, Japan; and Japan Iron and Steel Federation Period: 1978-1986 (9 years)

Outline of technology

1.Outline

3.Result of study

The formed-coke process (FCP) starts from noncaking coal as

1. Production of formed coke from 100% noncaking coal

the main raw material, prepares formed coal using a binder, and

Pilot plant operation was given normally with 70% noncaking coal

then carbonizes the coal in as-formed shape in a vertical furnace

and 30% caking coal. The operation with 100% noncaking coal

to obtain coke.

was also attained. 2.Establishing stable operation technology and engineering technology

2.Features

Long period of operation at the facility capacity of 200 t/d was

The FCP has a series of steps including raw material processing,

carried out. Production of 300 t/d (1.5 times the design capacity)

forming, carbonizing the formed coal, and cooling the carbonized

was achieved.

coke. In particular, carbonizing and cooling steps are conducted

Mcal/t-formed coal was achieved.

in a vertical furnace with closed system, providing many superior

3. Long period and continuous use of 20% formed coke in large

features in terms of work environment, work productivity,

blast furnace

easiness of stop and start up, and narrow installation space to

In an actual large blast furnace, long period and continuous

those of conventional chamber oven process.

operation test was carried out for 74 days with normal 20% and

Regarding the unit requirement of heat, 320

maximum 30% mixing rate of formed coke to confirm that the formed coke is applicable similar to the chamber oven coke.

4.Progress of research and development Table 1 Progress of research and development Fiscal year

1978

79

80

81

82

83

84

85

Core

Construction Pilot plant test Test operation

31

86

Clean Coal Technologies in Japan

Flow chart of continuous formed-coke production

Noncaking coal

Caking coal

Carbonizing stage

1.Drying

The formed coal is charged to the carbonization furnace (v), where the coal passes through the low temperature carbonizing zone, and then the coal is heated to 1000 C in the high temperature carbonizing zone (vii) to undergo carbonization. The heat-up rate is controlled so as the coal not to generate collapse and break caused by bulging and shrinking. The carbonized coal (coke), is cooled to 100 C or lower temperature in the cooling zone (viii) by a normal temperature gas injected from the bottom of the furnace before discharged from the furnace. O

2.Pulverizing

O

Binder

Forming stage Noncaking coal is the main 3.Kneading raw material (60-80%). The coal is dried to 2-3% of water content: (i). The dried coal is pulverized: (ii). A binder is added to the pulverized coal, 4.Forming which mixture is then kneaded: (iii), and formed: (iv), thus obtaining the Formed coal formed coal.

Generated gas The coke oven gas (300-350 C) leaving the top of the furnace is cooled by the precooler (ix) and the primary cooler (x). After removing tar mist in (xi), most of the gas is recycled to the furnace. The surplus portion of the gas is withdrawn from the system, which is then subjected to rectification and desulfurization to become a clean fuel having high calorific value, (3800kcal/Nm3). O

10.Primary 9.Precooler cooler 5.Carbonization furnace

11.Electric precipitator (Generated gas)

Main blower 6.Low temperature carbonizing zone

Ammonia water 12.Decanter Tar

7.High temperature carbonizing zone

Byproducts 8.Cooling zone

13.High temperature gas heating furnace

The liquid in the gas is introduced to the decanter (xii) to separate ammonia water and tar by decantation and precipitation. Each of these byproducts is sent to respective existing plants for further treatment. After treated, tar is reused as the binder for the formed coke.

15.Ejector

14.Low temperature gas heating furnace

Gas recycle Formed coke

The gas after separating tar mist in the electric precipitator is heated to about 1000 C in the high temperature gas heating furnace (xiii), and then is injected to the high temperature carbonizing zone (vii). The gas heated to 450 C in the low temperature gas heating furnace (xiv) drives the ejector (xv). The ejector (xv) sucks the high temperature gas which was used to cool the coke to feed to the low temperature carbonizing zone (vi) at a gas temperature of about 600 C. O

O

O

32

Part2 Outline of CCT Iron Making and General Industry Technologies (Iron Making Technologies)

2A2. Pulverized Coal Injection for Blast Furnace (PCI) In charge of research and development: Nippon Steel Corp. and other blast furnace steel making companies Period: Introducing the technology successively to domestic blast furnaces starting from 1981

Outline of technology

1.Background and process outline Injection of pulverized coal to blast furnace in Japan began at

4. Drying, pulverizing, and collecting coal are conducted in two

Oita No.1 blast furnace of Nippon Steel Corp. in 19811).

parallel lines to assure stable blast furnace operation.

Although the main reducing material in blast furnace is coke, the

5. Flow velocity of carrier air and pressure resistance of facilities are

blast furnace operation during and after the 1960s adopted heavy

determined with full consideration of preventing fire and explosion.

oil as an assistant fuel injecting from tuyere to enhance the

Bag Filter

productivity, efficiency, and scale up. After the two times of oil Cyclone

crisis, however, the high price of heavy oil forced the producers

Raw coal bunker

to switch the blast furnace operation to all-coke operation, or the Receiving hopper

reducing material had to fully depend on coke. Nevertheless, introduction of inexpensive assistant fuel instead of heavy oil was wanted to reduce the cost of blast furnace operation and to

Reservoir tank P.A.fan

type pulverized coal injection system first in Japan, (Fig.1). The

Distributor

Feeder

In this regard, Oita No.1 blast furnace introduced the ARMCO

Air heater

Pulverizer

features of the system are the following. 1. High pressure transportation and injection lines have no

1

2

Feed tank

furnace Disperser

mechanical rotation part, which avoids troubles of wear and

3

Transport line

secure stable operation of the blast furnace.

damage. 2. Applied gas is not recycled to assure reliability of operation.

N2 compressor

3. Distribution of pulverized coal charged to individual tuyeres ensures uniform distribution utilizing the geometrically symmetric

O.T.

Air compressor

flow characteristic of fluid.

Fig.1 Pulverized coal injection facility at Oita No.1 blast furnace

2.Development object and technology to be developed The introduced technology has field results in abroad.

2. Model plant test (1 t/h scale) for coal treatment, transportation,

Considering the differences in facility configuration and scale,

and control.

and in operating conditions between abroad and Japan, the study

3. Test on actual furnace injecting coal through a single tuyere:

team conducted tests and investigations focusing on the

Combustibility evaluation at the tuyere of actual furnace;

following-listed items, and reflected the result on the design.

sampling and evaluation of coke inside the furnace.

1. Pulverized coal combustion test: Evaluation of influence of

4. Distribution of pulverized coal along circumference: With a

grade and size of pulverized coal; temperature, pressure, and

model of actual furnace size, grasping powder flow characteristic

oxygen rich condition of air feed; and other variables.

and determining distribution accuracy.

3.Progress and result of the development Considering the heavy oil injection level during increased

1982.

production rate period and the experienced long time result, the

introduced the U.S. Petrocarb technology and constructed

capacity of Oita No.1 blast furnace was designed to 80 kg/t. Two

Kakogawa No.2 blast furnace and Kobe No.3 blast furnace in

lines of mill each having 25 t/h capacity were installed. After the

1983 as the Kobelco system. After that, Nippon Steel Nagoya

start of the plant, facility operation and injection operation

No.1 blast furnace of ARMCO type and Nisshin Steel Kure No.2

proceeded smoothly to establish the stable production system.

blast furnace of ARMCO type entered commercial operation in

After the success of Oita No.1 blast furnace, Godo Steel, Ltd.

1984.

started the operation of the exclusively-developed system in

furnace was adopted by 16 blast furnaces in Japan, accounting

33

Following the domestic technology, Kobe Steel, Ltd.

In 1986, the pulverized coal injection facility for blast

Clean Coal Technologies in Japan 200

for 50% of the total. The number increased to 25 blast furnaces

550

in 1996. In 1998, all the operating domestic blast furnaces had average pulverized coal ratio to 130 kg/t level, (Fig. 2). Table 1 shows the various types of injection for the blast furnace pulverized coal facilities.

Table 2 shows the highest level in

Japan of a typical operational index of blast furnace during the operation with pulverized coal injection.

150

500 coke rate(mean)

PC rate(mean)

100

450

50

400

Coke Rate(kg/t-pig)

PC rate(kg/t-pig),Number of PCIBF

the pulverized coal injection facility, which increased the domestic

number of BF equiped PCI 0 1980

350

2000

1990 year

Fig. 2 Increase in applications of pulverized coal injection for blast furnace in Japan Table 1 Various facility types of pulverized coal injection to blast furnace Pneumatic conveying concentration

Velocity

Low

High

Carrier gas pressure and flow rate (Downtake)

National Steel, Kobe Steel, JFE (NKK)

Medium

Low

High

ditto (Uptake)

JFE (Kawasaki Steel)

Medium

High

Low

ditto + Flow meter

Thyssen

Medium

Low

Rotary Valve

Dunkerque

Medium

Simon Macawber

Low

High

Coal Pump

Scunthorpe

Large

ARMCO

Low

High

Uniformly distributing to give uniform pressure drop across in individual pipes

Nippon Steel Corp., Hoogovens

Small

High

Low

Uniformly distribution by throttled pipes

Sidmar, Solac Fod

Small

High

Low

ditto

Dunkerque, Taranto

Small

Low

Rotary Feeder+Uniform pressure drop (one way) distribution

Sumitomo Medium Metal Mining. Co., Ltd.

Name of type

Type of distribution /transportation

Petrocarb Pneumatic conveying from feed tank directly to each tuyere

DENKA Kuettner ex-PW

Feed tank Main pipe Distributor Tuyere

new PW Klockner Sumitomo Metal Mining. Co., Ltd.

Low

Control of flow rate in branched pipe

Investment

Use

Large

Table 2 Domestic highest level operation indexes for blast furnace operation with pulverized coal injection Year and Month

Steel works, blast furnace

Coal dust ratio kg/t

Coke ratio kg/t

Reducing material ratio kg/t

Tapping ratio t/d/m3

Maximum pulverized coal ratio (PCR)

98.6

Fukuyama No.3 blast furnace

266

289

555

1.84

Minimum coke ratio (CR)

99.3

Kobe No.3 blast furnace

214

288

502

2.06

Minimum reducing material ratio (RAR)

94.3

Oita No.1 blast furnace

122

342

464

1.95

Maximum tapping ratio

97.1

Nagoya No.1 blast furnace

137

350

487

2.63

4.Issues and feasibility of practical application Average operating years of domestic coke ovens have reached

possibility of innovation of blast furnace toward a combined

around 30 years, and the importance of the technology of

smelting furnace through the combined injection via tuyeres of

injection of pulverized coal as an assistant fuel for blast furnace

blast furnace together with reducing materials such as waste

increases year after year. Compared with coke which depends on

plastics and biomass, and further with reducing ores. Thus, the

caking coal, pulverized coal increases the expectation for the

technology is expected to develop as a core technology of blast

injection material owing to the flexible adaptability to the coal

furnace solving the issues of resources, energy, and carbon

resources.

dioxide.

The technology of pulverized coal injection has a

Reference

Shinjiro Waguri: Ferram vol.8, p371 (2003) 34

Part2 Outline of CCT Iron Making and General Industry Technologies (Iron Making Technologies)

2A3. Direct Iron Ore Smelting Reduction Process (DIOS) In charge of research and development: Center for Coal Utilization, Japan; and Japan Iron and Steel Federation Period:1988-1995 (8 years)

Outline of technology

1.Outline

3.Result of study

The DIOS directly uses noncaking coal in powder or granular

Feasibility study was given to new installation of commercial

shape and iron ore without using coke process and sintering

plant of blast furnace process and of DIOS at seaside green field.

process which are required in blast furnace process.

The

Considering its superiority to blast furnace process as described

noncaking coal is directly charged to a smelting reduction

below, the feasibility of DIOS can be demonstrated for the model

furnace, while the iron ore is preliminarily reduced before

of 6,000 tons of molten iron production (annual production of 2

charged to the furnace, thus the molten iron is produced.

million tons). 1. Investment cost is decreased by 35%.

2.Features

2. Molten iron production cost is decreased by 19%.

1. Applicable of inexpensive raw material and fuel, (noncaking

3. Coal consumption per 1 ton of molten iron production is the

coal, in-house dust, etc.)

same level with that of the blast furnace process, 730-750 kg.

2. Low operation cost

4. Net energy consumption is decreased by 3 to 4%.

3.Responding flexibly to variations of production rate

5. CO2 emissions in the iron making process is decreased by 4 to 5%.

4. Compact facilities, and low additional investment 5. Available in stable supply of high quality iron source 6. Effective use of coal energy 7. Easy coproduction of energy (cogeneration) 8. Low environmental load, (low SOx, NOx, CO2, dust generation, no coke oven gas leak)

4.Progress of research and development Table 1 Progress of research and development Fiscal year

1988

89

90

91

92

93

94

95

Core

Construction Test operation

Pilot plant test

1) Core technology study (FY1988-FY1990)

2. With various raw materials, the conditions of facilities and of

Core technologies necessary for the construction of pilot plant

operation to achieve high thermal efficiency to substitute the blast

were established. These core technologies include the increase

furnace were determined.

in thermal efficiency of smelting reduction furnace (SRF), the

3. Technology for water cooling of furnace body was established.

connection with preliminary reduction furnace (PRF), the molten

Conceptual design and economy evaluation (FS) for commercial

slag discharge technology, and the SRF scale up.

facilities were conducted.

2) Pilot plant test (FY1993-FY1995)

operation to prove the superiority to the blast furnace as shown in

1. Applicability of direct use of powder and granular ore and coal

the results of the research was clarified.

was confirmed, and necessary facility conditions were determined.

35

The conditions of facilities and of

Clean Coal Technologies in Japan

Coal 952kg

Flux 80kg

Plant size

500 t-molten iron/day

Smelting reduction furnace

Height 9.3m. Inner diameter 3.7m. Pressure less than 2.0kg/cm2 - G(300kPa)

Prereduction furnace

Height 8.0m. Inner diameter 2.7m.

Iron ore 1450kg Preheating furnace

RD 8.7% 2,326Nm3 2,789Mcal(11.7GJ)

RD 8.6% 600 C O

Prereduction furnace Venturi scrubber RD 27.0% 779 C O

O2 608Nm3

RD 27.1%

Pressure control value

OD 31.6% Off-gas

Tapping device Smelting reduction furnace 1.9kg/cm2 - G(290kPa) Molten iron

24.7t/h 1,540OC 1,000kg Legend

N2 70Nm3

OD : Oxidation degree RD : Reduction degree

Fig.1 An example of the DIOS pilot plant operation (per 1,000kg of molten iron)

36

Part2 Outline of CCT Iron Making and General Industry Technologies (Iron Making Technologies)

Super Coke Oven for Productivity and Environment Enhancement

2A4. toward the 21st Century (SCOPE21)

In charge of research and development: Center for Coal Utilization, Japan; and Japan Iron and Steel Federation Project type: Coal Production and Utilization Technology Promotion Grant Period:1994-2003 (10 years)

Outline of technology

1.Background and process outline The existing coke production process,which rapidly heats the coal

The SCOPE21 process aims to develop an innovative process

at 350 C(low temperature carbonization),as opposed to the old

responding to the need in 21st century in terms of effective use of

method of a 1200OC coke furnace, has many problems such as

coal resource, improvement in productivity, and environmental

unavoidable coal grade limitation of using mainly strong caking

and energy technologies. As shown in the figure, the existing

coke owing to the limitation of coke strength, large energy

coke production process is divided into three stages along the

consumption

O

and

process flow, namely the coal rapid heating, the rapid carbonization,

environmental issues. Coke ovens in Japan have reached their

owing

to

the

process

characteristic,

and the medium-to-low temperature coke reforming. Development

average life of 30 years, and enter their replacement time. In this

was carried out of a revolutionary process with overall balance

occasion of requirement for replacement, there is a need to

that pursued the functions of each stage the utmost.

develop an innovative next-generation coke production technology that has flexibility to handle coal resource and that has excellent

Currently the SCOPE21 is only one large development project for

environmental measures, energy saving, and productivity.

new coke process in the world, and it is hoped that it can be put

Responding to the need, the team develops a new coke process.

to practicul use.

Hot briquetting machine Plug flow conveying system

Stationary charge unit

Highly sealed oven door Pneumatic preheater

Emission free coke pushing

Coke upgrading

Carbonizing chamber

Coarse coal

Fine coal Stack

Coal

High heat conductivity brick Pressure control (750-850OC)

Fluidized bed dryer

Steam

Regenerator Foundation

Fuel

Power plant

Smokeless discharge

Hot blast stove

Coke (150-200OC) Coke sealed transportation (750-850OC) Blast furnace

Flue gas

Fig.1 Outline of the next-generation coke oven process

2.Development object and technology to be developed (1)Increasing the use ratio of noncaking coal to 50%

current level, the study significantly reduces the carbonizing time

With the aim of increasing the use ratio of noncaking coal to

by increasing the thermal conductivity of wall of the carbonizing

50%, which noncaking coal is not suitable for coke production

chamber and by discharging the material at temperatures lower

and the current use ratio is only about 20%, the study develops

than normal carbonization point, (medium-to-low temperature

the technology to increase the bulk density of charging coal

carbonization).

through the improvement of caking property utilizing the coal

temperature is compensated by reheating in the coke dry

rapid heating technology and through the forming treatment of

quenching unit (CDQ) to secure the product quality.

fine coal powder.

(3)Reducing NOx generation by 30% and achieving smokeless,

(2)Increasing the productivity by three times

odorless, and dustless operation

The

resulting

insufficient

carbonization

Full scale prevention of generation of smoke, odor, and dust

Aiming at the increase in the productivity by three times that of 37

Clean Coal Technologies in Japan during coke production is attained by the sealed transportation of

20% through the increase in the temperature to start the

coal using the plug transportation, the sealed transportation of

carbonization by preheating the charging coal to high

coke, and the prevention of gas leak from coke oven applying

temperature, the reduction in the carbonization heat by reducing

intrafurnace pressure control. Furthermore, improved combustor

the discharging temperature applying medium-to-low temperature

structure of the coke oven reduces NOx generation.

carbonization, and the easy recovery of sensible heat of

(4)Saving energy by 20%

generated gas and of combustion flue gas owing to the scale-

The energy necessary to produce coke is aimed to reduce by

reduction of facilities resulted by the increased productivity.

3.Progress and result of the development The project proceeds under the joint work of Center for Coal Utilization, Japan and Japan Iron and Steel Federation. The pilot plant (6 t/h) was constructed in Nagoya Works of Nippon Steel Corp., (refer to photograph), and the test operation was conducted.

Energy saving and Economical Evaluation The SCOPE21 process is composed of innovative technologies, enabling effective use of coal resources, energy saving, and environment enhancement. As a result, it has a great economical advantage over the conventional process. [Reduction of construction costs] Coal Preliminary

Common equipment

Total

Conventional

89

---

11

100

SCOPE21

40

25

19

84

Construction costs Reduction by 16% by greatly reducing the number of coke ovens even while expanding the coal pretreatment plants and environmental protection. Coke production cost Reduction by 18% by increasing the poor coking coal ratio and decreasing construction costs even while increasing electricity and fuel gas in the coal pretreatment plant.

[Evaluation consumption]

[Reduction of coke production costs] 100

800

Energy consumption (Mcal/t-coal)

Energy saving Reduction of total energy use by 21% due to adopting a pretreatment process with direct heating of coal and a high effciency coke oven with a heat recovery system.

Photo 1 Total view of pilot plant

Power Fuel gas

70 600

CDO Recovered 271

133

400

Coke Production cost (%)

Coke over

CDO recovered 277

600 200

Total 399

460 Total 316

80

Variable 47 Variable 38

60

40 Fixed 53

20

0

Fixed 44

0

Conventional

SCOPE21

Conventional

SCOPE21

SCOPE21 Development schedule 1994

95

96

97

98

99

2000

01

02

03

Survey and study

Core technology development

Core technology combination test Disassembly and investigation

Construction Pilot plant study

Test operation

(4)Issue and feasibility of practical application The aging of coke ovens in Japan proceeds, though there are

changed. The developed technology will be introduced to these

progresses of furnace repair technology. Thus coke ovens still

aged coke ovens, though it is influenced by the economic

need replacement and the replacement schedule has not been

conditions.

Reference

1) Kunihiko Nishioka et al.: Lecture papers at the 12th Coal Utilization Technology Congress, Tokyo, p.1-2.1, November (2002)

38

Part2 Outline of CCT Iron Making and General Industry Technologies (General Industry Technologies)

2B1. Fluidized Bed Advanced Cement Kiln System (FAKS) Outline of technology

1.Features The objectives of development of fluidized bed advanced cement kiln system (FAKS) are the efficient combustion of low grade coal, the significant reduction of NOx emissions, and increase in the heat recovery efficiency between solids and gases discharged from the process by utilizing the inherent characteristics of fluidized bed process, including combustion performance, heat transfer performance, particle diffusion and granulation properties.

Thus, the ultimate object of the

development is to contribute to the global environment conservation, the energy saving, and the fulfillment of demand of various kind and/or special grade cement.

Cement clinker

Photo 1 Clinker produced from fluidized bed kiln

Photo 2 Total view of 200 t/d plant

2.Outline of technology The FAKS is configurated by a granulation sintering kiln and twostage coolers. The granulation sintering kiln granulates the raw material to a specific size for melting to high quality cement, and then sinters thus granulated raw material at high temperatures. The two-stage coolers combine a fluidized bed

cooler and a

packed bed slow-cooling cooler to increase the heat recovery efficiency. The most important technology in the system is the granulation control technology. Compared with the other development which needed "charge of the seed-core clinker as the core of the granule from outer side for controlling the granulation process, thus allowing high temperature raw material to adhere and grow on the seed-core clinker", the FAKS process applies "hot selfgranulation" for the first time in the world.

The "hot self-

granulation" is "the process where a nucleus of granule is generated by agglomerating the small particle of raw material, and to allow other raw material to adhere and grow on the nucleus, thus to conduct the granulation control." The granulation sintering kiln furnace integrates two major technologies for performing the granulation control: a raw material injection unit, and a bottom classification and discharge unit.

Fig.1 FAKS-I System structure

39

Clean Coal Technologies in Japan

3.Demonstration site and use field 1)Demonstration site : Tochigi plant of Sumitomo Osaka Cement Co., Ltd. 2)Use field : Cement production 3)Development period : 1996-1998

Fig.2 Key Technology

4.Progress of development On the result of basic study begun from 1984 by the joint team of

Ltd., and Sumitomo Osaka Cement Co., Ltd. Then the pilot plant

Kawasaki Heavy Industries, Ltd. and Sumitomo Osaka Cement

operation test began. From April 1993, the basic plan and design

Co., Ltd., the technology development proceeded beginning from

started for a 200 t/d plant jointly by Center for Coal Utilization,

1986 as the Coal Production and Utilization Technology

Japan, and Japan Cement Association. Through the operation

Promotion Grant project which is a project of Agency of Natural

test toward the practical application begun from February 1996,

Resources and Energy of the Ministry of International Trade and

the system was validated, and the development work completed

Industry. A 20 t/d pilot plant was constructed in June 1989 jointly

at the end of December 1997.

by Center for Coal Utilization, Japan, Kawasaki Heavy Industries, 5.Issues The performance comparison between the conventional

adopted as an innovative substitute cement production

technology and FAKS for a 1,000 t/d commercial plant is shown

technology.

in the table below. The FAKS is expected to be commercially Comparison of rotary kiln type process and FAKS at a 1,000 t/d plant in terms of environmental improvement effect Discharge quantity NO2 as N content in coal is 1% and NOx convert in 10% O2 CO2 *1 depends on electric power and fuel consumption

Rotary Kiln & AQC

FAKS

Discharge quantity (mg/Nm3)

708

476

Annual discharge quantity (ton-NO2/year)

341

233

Discharge quantity(g/Nm3)

245

220

Annual discharge quantity (ton-CO2/year)

118x103

108x103

ton-clinker/day

1,000

1,000

ton-cement/day

1,050

1,050

330

330

3,411x103

2,993x103

Basis of calculation Production capacity Annual operating time

Day/year

Heat consumption

kJ/ton-clinker

Power consumption

KWh/ton-clinker

Exhaust gas specific quantity

Nm3/kg-clinker

Lower calorific value of coal

kJ/kg-coal

27

36

1.46

1.49

25,116

25,116

*1 Based on IPCC : Guideline for National Greenhouse Gas Inventories, Reference Manual Carbon Emission Coefficient / Basic Calculation ; Carbon Emission Factor = 26.8 tC/TJ , Fraction of Carbon oxidized = 0.98

Reference

1) Isao Hashimoto, Tatsuya Watanabe, et al.: Development of Fluidized Bed Advanced Cement Kiln Process Technology (Part 9), The 8th Coal Utilization Technology Congress, Japan, September (1998)

40

Part2 Outline of CCT Iron Making and General Industry Technologies (General Industry Technologies)

2B2. New Scrap Recycling Process (NSR) In charge of research and development: Center for Coal Utilization, Japan; Nippon Sanso Corp.; and NKK Corp. (present JFE Steel Corporation) Project type: Coal Production and Utilization Technology Promotion Grant Period:1992-1997 (6 years)

Outline of technology

1.Background In Japan, currently about 30 million tons of iron scrap is recycled

energy efficiency is wanted. To this point, the NSR process is a

every year, and most of them are melted in arc furnaces

non-power melting technology that melts metals such as iron

consuming large amount of electric power. The energy efficiency

scrap utilizing high temperature energy obtained from direct

of arc furnace is as low as about 25% (converted to primary

combustion of pulverized coal by oxygen. The NSR process has

energy taking into account of efficiency of power generation and

been developed aiming to significantly increase the energy

of power transmission). Thus a melting process having higher

efficiency compared with that of conventional technology.

2.Development schedule The development was promoted by a joint team of Center for

efficiency melting. The study began from a batchwise melting

Coal Utilization, Japan, Nippon Sanso Corp., and NKK Corp.

furnace.

(present JFE Steel Corporation). The main subject of development

continuous melting furnace was developed aiming at higher

was the furnace structure and the burner arrangement to attain high

energy efficiency.

With the result of the batch-furnace operation, the

Table 1 Development schedule 1992

1993

1994

1995

1996

1997

Survey Bench scale (1 t/batch)

Batch-furnace

Pilot plant scale (5 t/batch) Continuous furnace (pilot plant scale: 6 t/h)

3.Outline of process and result of study Figure 1 shows the process outline of the continuous melting

the pulverized coal.

furnace.

The melting furnace has a melting section, basin

With the above-described system, even pulverized coal normally

section, and holding section, each of which is separately

giving slow combustion rate can be combusted at high rate and

functioned. Each section has pulverized coal - oxygen burner.

high efficiency similar with those of liquid fuel such as heavy oil.

The oxygen supplied to the burner is preheated to high

The melting section is in shaft shape, where the raw material

temperatures (400-600 C) by an oxygen preheater to combust

charged from top of the furnace is directly melted by the burner

O

Bag filter Flue gas

Blower Raw material Oxygen generator

Open/close damper

Burner controller

Slide gate

Oxygen preheater

Pulverized coal tank

Pulverized coal oxygen burner

Pulverized coal charge unit Tuyere Nitrogen generator

Molten steel

Fig. 1 NSR process flow

Fig. 2 Pilot plant (6t/h) 41

Clean Coal Technologies in Japan

flame at lower section of the furnace. The melted raw material

transmission. Compared with normal arc furnace, the melting

flows through the basin section and enters the holding section.

energy was reduced by 40%, achieving high energy efficiency.

The basin section soaks the molten steel. The carbon content of

Furthermore, the process achieved highly superior result to the

the molten steel in the basin section can be controlled by

conventional process in terms of environmental measures such

injecting powder coke into the furnace.

The holding section

as the significant suppression of generation of dust (excluding

stores the molten steel for a specified period, and rapidly heats

ash in pulverized coal) and of dioxins owing to the control of

the molten steel to about 1,600 C, and then taps the molten steel

intrafurnace atmosphere.

O

by the EBT system. To the basin section and the holding section, molten steel agitation gas is injected from bottom of the

1600 Coke

respective furnaces to enhance the heat transfer from flame to 1400

molten steel and the slag-metal reaction. All the combustion gas Melting energy(Mcal/T)

coming from individual sections passes through the melting section, and is vented from the furnace top after being used to preheat the raw material in the melting section. The raw material is continuously charged from the furnace top and melted in the furnace.

The tapping from the holding section is conducted

intermittently. The process effectively utilizes the heat transfer characteristics of

Oxygen

1200 1000 800

Electric power

600 400 Pulverized coal

200

oxygen burner, and achieves high efficiency melting. Figure 3

0

shows the result of comparison of melting energy between the

EAF (380Wh/T)

process and the arc furnace. The electric power (oxygen is also added because it is produced by electricity) is counted to the

NSR

Fig. 3 Comparison of melting energy

primary energy including loss of power generation and of power

4.Toward practical application The study team has already completed the design for actual

process is a non-power melting technology which is few in the

scale facilities. With the influence of current poor economy in the

world, and has a strong advantage of not influenced by electric

electric furnace industry, however, the process has not been

power infrastructure, the study team continues to make efforts

brought into practical application.

toward the practical applications also in abroad.

Nevertheless, since the

Fig. 4 Commercial scale plant (50 t/h)

References

1) Hiroshi Igarashi, Toshio Suwa, Yukinori Ariga, and Nobuaki Kobayashi: ZAIRYO TO PROCESS (Materials and Processes), Vo.12, No.1, p135 (1999) 2) Hiroshi Igarashi, Nobuaki Kobayashi, and Hiroyuki Nakabayashi: Technical Bulletin of Nippon Sanso Corp., (19) pp30-37 (2000)

42

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Liquefaction Technologies)

3A1. Coal Liquefaction Technology Development in Japan Outline of technology

1.Background of Coal Liquefaction Technology Development Since the Industrial Revolution, coal has been used as an

Development History of NEDOL Process

important source of energy by humankind. Coal consumption

Year

surpassed that of firewood and charcoal for the first time in the latter half of the nineteenth century, making coal the world’s major source of

energy.

In Japan, coal also became the

predominant energy source in the twentieth century.

Articles and others Three liquefaction processes

In the

1979

The Sunshine Project started (July, 1974) Research on three liquefaction processes started.

1980

(1) Solvent Extraction Process (2) Direct Hydrogenation Process (3) Solvolysis Process

1981

NEDO established (Oct. 1, 1980), succeeding three liquefaction processes of Coal Technology Development Office.

1960s, however, the presence of coal gradually faded as it was 1982

replaced by easier-to-use oil. It was after the oil crises of 1973

1983

and 1978 that coal was thought highly of once again. With the oil crises as a turning point, the development of oil-alternative

1984

energy, particularly coal utilization technology, came under the

1985

spotlight amid calls for the diversification of energy sources.

1986

During that time, liquefaction of coal, which had been positioned

1987

as the strongest oil-alternative energy contender because of its

1988

huge reserves, was undergoing development in many countries.

1989

Research in Germany and the United States involved pilot plants

1990

with the capacity to treat hundreds of tons of coal per day.

1991 1992

was being promoted under the Sunshine Project mainly by the Energy

and

Industrial

Technology

Conceptual design of 250 t/d

-NCOL established (Oct. 1, 1984)

A 150 t/d pilot plant started.

Construction

1995 1996

t/d-scale pilot plant for the liquefaction of bituminous coal in 1998

1997

with substantial results, thereby drawing equal with Germany and

1998

Operation

-Coal-in RUN-7 (-Sept. 9, 1998)

liquefaction technology. Coal-producing countries such as China

1999

and

2000

interested

in

Recommendations to the 48th Subcommittee Meeting for Coal Conversion (March, 1995) The period of research extended for completion (March 31, 1999) -The Research Center inaugurated (June 24, 1995) -The ground-breaking ceremony for a pilot plant held (July 10,1996) -Coal-in trial run (Nov. 26-29, 1996, Feb. 25-27, 1997) -Coal-in RUN-1 (March 26, 1997-)

the United States as well as establishing state-of-the-art coal strongly

Review of total project costs toward reduction (April, 1991, agreed upon at the operation meeting.) -Kashima Establishment opened (Oct. 1, 1991). -The ground-breaking ceremony for a pilot plant held (Nov. 25, 1991)Construction , NEDO s Coal Technology Development Office reorganized into CCTC (Oct., 1992). Total project costs reconsidered to be clearly defined in value (Nov., 1992). Set at 68.8 billion yen. The New Sunshine Project costs (1993)

1994

progress led to the successful completion of operations of a 150

also

(Downscaled from 250 t/d to 150 t/d.)

150 t/d design

1993

Germany and the United States, slow but steady development

are

Basic concept Conceptual design preparation

PDU (1 t/d of Sumitomo Metals-Hasaki)-based PSU (1 t/d of Nippon Steel-Kimitsu)-based research (design) started (around 1985). PSU operation research started (1987).

Development

Organization (NEDO). Despite the lag of a decade or so behind

Indonesia

Unification of three processes/development of NEDOL Process

250 t/d design

In Japan as well, development of coal liquefaction technology New

1st interim report (the same as the Joint Council report mentioned below) (Aug., 1983) The unification of three liquefaction processes recommended. NEDO set out for conceptual pilot plant planning (three processes and a proposal for their unification)

the

Cleaning, etc. Research on dismantlement Removal

commercialization of coal liquefaction technology, with high

2001

Total coal-in time of 6,062 hours or 262 days (excluding that for trial runs) The longest coal-in continuous run time of 1,921 hours -Operation completion ceremony held on Sept. 29, 1998. -Pilot plant operation completion report meeting held (Dec. 1, 1998) at a Gakushi Kaikan hall. -Pilot plant operation research completed (March 31, 2000).

expectations for its future development.

2.History of Coal Liquefaction Technology Development in Japan 2.1 Dawning of coal liquefaction technology development

in 1940 with the completion of an oil synthesis plant annually

Between around 1920 and 1930, South Manchurian Railway Co.,

producing thirty thousand tons of coal oil.

Ltd. started basic research on coal liquefaction using the Bergius

Under the background of a wartime situation, production of

Process and, around 1935, initiated operation of a bench-scale

synthetic oil was continued until the end of World War II.

PDU (process development unit) plant. Based on this research,

2.2 Post-war research on coal liquefaction

a plant annually producing twenty thousand tons of coal oil was

Immediately after the war, the U.S. Armed Forces Headquarters

built at Wushun Coal Mine, China, and operated until 1943. In

banned research into coal liquefaction, alleging that it was

the meantime, Korean Artificial Petroleum Co., Ltd. succeeded

military research.

between 1938 and 1943 at its Agochi factory in the continuous

resumed at national laboratories and universities. This was not,

operation of a direct coal liquefaction plant capable of treating

however, research on coal oil production but the production of

100 t/d of coal. Production of coal oil at both of the above plants

chemicals from high-pressure hydrocracking of coal, which was

was suspended at the request of the military to use the plants for

continued until around 1975.

hydrogenation of heavy oil or to produce methanol.

The Sunshine Project was inaugurated in 1974 on the heels of

At around 1930, besides the direct coal liquefaction method

the first oil crisis, encouraging efforts to devise liquefaction

(Fischer Process), the Bergius Process was used as an indirect

technology unique to Japan as part of an oil-alternative energy

coal liquefaction method to study coal liquefaction technology

development program. Under the Sunshine Project, technological

and to produce synthetic oil.

The Fischer Process was

development has been undertaken for the three coal liquefaction

introduced into Japan upon its announcement in Germany in

processes of Solvolysis, Solvent Extraction, and Direct

1935 and, in 1937, plant construction started in Miike, winding up

In 1955, coal liquefaction research was

Hydrogenation to liquefy bituminous coal. R&D of brown coal 43

Clean Coal Technologies in Japan

liquefaction processes has also 2.3 Amalgamation of three coal

Solvent Extraction System (PDU) (Catalyst) Coal Liquefaction reaction Solvent

liquefaction processes

Separation

Coal oil Solvent

450OC,150atm Hydrogen Solvent hydrogen

With the oil crises as an impetus, the

(Medium to a little heavy)

Ni-Mo catalyst

Solvent hydrogenation technology

taken place since the end of 1980.

NEDOL Process High-performance catalyst (Fe)

Coal Liquefaction reaction

Separation

Solvent

Direct Hydrogenation System (PDU)

development was incorporated for

High-performance catalyst (Fe)

further promotion into the Sunshine

Coal

Project based on Japan’s international

Solvent

Liquefaction reaction

obligations and the need for a large, supply

of

liquid

Coal oil Solvent

fuel; Solvolysis System (PDU)

diversification of energy sources and development of oil-alternative energy

Coal Solvent

Ni-Mo catalyst Degree of dissolution

SRC

(Ultra-heavy oil) 450OC150atm

held great significance.

Deashing

Liquefaction reaction

Separation

Coal oil Solvent

Ash Hydrogen 400OC,150atm

In 1983, NEDO (the New Energy Development

Organization,

Solvent hardening technology

constant

Separation

450OC,250atm Hydrogen

450 C,170atm Hydrogen

high-performance catalyst technology

practice of coal liquefaction technology

Coal oil Solvent

O

Ni-Mo catalyst

Solvent hydrogen (Heavy) Hydrogen

[Referential] EOS Process (U.S.) Ni-Mo catalyst

450OC,140atm

Coal

Liquefaction reaction

Separation

Solvent,hydrogen

Solvent

Coal oil Solvent

Bottom recycle

Hydrogen

Hydrogen

Fig. 1 Basic Philosophy of NEDOL Process

the

present New Energy and Industrial Technology Development

(3) Result from Solvolysis Liquefaction Process: For priority acquisition

Organization) assembled the R&D results thus far obtained from the

of light oil, it is effective to thicken the circulation solvent.

three bituminous coal liquefaction processes as follows:

These three processes were amalgamated on the strength of their

(1) Result from Direct Hydrogenation Process: Under any of certain

features into the NEDOL Process.

reaction conditions, the better the catalyst function, the higher the liquid

2.4 Bituminous coal liquefaction technology development (NEDOL Process)

yield rate becomes.

Bituminous coal liquefaction technology development is described in

(2) Result from Solvent Extraction Process: Hydrogen offers liquefaction

[3A-2].

under mild conditions.

2.5 Brown coal liquefaction technology development (BCL Process) Brown coal liquefaction technology development is described in [3A-3].

3. Coal Liquefaction in the Future China, expecting stringency in its oil supply-demand situation for

operation concluded in a shift from the research stage to the

sometime in the future, takes an active stance toward the

commercialization stage. It seems that commercialization will be

development/adoption of coal liquefaction technology.

NEDO, as

enhanced particularly through international cooperation with coal-

part of its international cooperation program, installed 0.1 t/d

producing countries such as China and Indonesia. In China, not

liquefaction equipment in China in 1982 for subsequent utilization

only Japan but also the United States and Germany have embarked

such as in liquefaction tests of Chinese coal, exploration of catalysts

on feasibility studies of location with commercialization in mind.

for liquefaction, and human capacity building. Since 1997, at the Yilan coal Japan (CCUJ-JICA)

request of China, cooperation has been offered for the implementation of feasibility studies on the location of a coal liquefaction plant using Yilan coal of Heilongjiang Province.

Shenhua coal U.S. (HTI-USDOE) Japan (NEDO)

Furthermore, a survey entrusted by China estimates Shenhua coal

HEILONGJIANG Harbin

reserves in Shenxi Province/Inner Mongolia Autonomous Region at JILIN

MONGOLIA

as much as 200 billion tons, justifying high expectations for coal as It is further considered certain that Indonesia will become a net oilimporting country in the near future.

In 1992, the Indonesian

GANSU

SHANXI SHANDONG

NINGXIA HUIZU

QINGHAI

government requested cooperation in coal liquefaction research on Indonesian brown coal.

LIAONING

NEIMONGGOL HEBEI Beijing

an inexpensive source of energy.

SHAANXI

In response, NEDO signed in 1994 a

JIANGSU HENAN ANHUI

memorandum on cooperative coal liquefaction research with the

SICHUAN

Agency for the Assessment and Application of Technology of

HUBEI ZHEJIANG HUNAN

Indonesia (BPPT) and began a new round of brown coal liquefaction

GUIZHOU

JIANGXI FUJIAN

Kunming YUNNAN

technology development that aimed at the realization of commercial

GUANGDONG GUANGXI ZHUANGZU

TAIWAN

plants for Indonesian brown coal. Coal liquefaction technology development that has continued since

Xianfeng coal Germany(Ruhr Kohle-Nordrhein Westfalen State)

the Sunshine Project was inaugurated in 1974 has now seen plant Fig. 2 Review of Coal Liquefaction for Commercialization in China References

1) Sadao Wasaka: "Bulletin of The Japan Institute of Energy", 78 (798), 1999 2) "Development of Coal Liquefaction Technology - A Bridge for Commercialization", Nippon Coal Oil Co., Ltd. 3) Haruhiko Yoshida: "Coal Liquefaction Pilot Plant", New Energy and Industrial Technology Development Organization 44

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Liquefaction Technologies)

3A2. Bituminous Coal Liquefaction Technology (NEDOL) In charge of research and development: New Energy and Industrial Technology Development Organization; Nippon Coal Oil Co., Ltd. [Sumitomo Metal Industries, Ltd.; Idemitsu Kosan Co., Ltd.; Nippon Steel Corp.; Chiyoda Corp.; NKK Corp.; Hitachi Ltd.; Mitsui Coal Liquefaction Co., Ltd.; Mitsui Engineering & Shipbuilding Co., Ltd.; Mitsubishi Heavy Industries, Ltd.; Kobe Steel, Ltd.; Japan Energy Co., Ltd.; Sumitomo Metal Mining Co., Ltd.; Asahi Chemical Industry, Co., Ltd.; Toyota Motor Corp.; Sumitomo Coal Mining Co., Ltd.; Nissan Motor Co., Ltd.; The Japan Steel Works, Ltd.; Yokogawa Electric Corp.; and The Industrial Bank of Japan, Ltd.] Project type: Development of bituminous coal liquefaction technology, and development of NEDOL Process Period: 1983-2000 (18 years)

1. Outline of NEDOL Process development

2. Evaluation of NEDOL Process

The conceptual design of a 250 t/d pilot plant (PP) began in

Figure 1 shows the progress of coal liquefaction technology since

FY1984. Owing to changes in economic conditions, however, the

before World War II, expressed by the relation between the

design of a 150 t/d PP began in FY1988. As a support study to

severity of liquefaction reaction and the yield of coal-liquefied oil

the pilot plant, the operational study of a 1 t/d process support

in individual generations.

unit (PSU) was carried out.

Process is competitive with the processes in Europe and the

The 1 t/d PSU, constructed in FY1988 at Kimitsu Ironworks of

United States in terms of technology, economics, and operational

Nippon Steel Corp., consists of four stages: coal storage and

stability, and thus the NEDOL Process is one of the most

pretreatment, liquefaction reaction, coal liquefied oil distillation,

advanced processes in the field, reaching a position to shift to

and solvent hydrogenation. Over the ten-year period from

commercialization in the shortest amount of time.

FY1989 to FY1998, the joint study team of Nippon Steel Corp.,

Large

Outline of technology

Mitsui Coal Liquefaction Co., Ltd., and Nippon Coal Oil Co., Ltd. conditions. Through the 26,949 hours of cumulative coal slurry operations, the stability and the overall operability of the NEDOL Process were confirmed, and optimization of the process was established. Finally, the necessary design data was acquired. Construction of the 150 t/d PP was launched in 1991 at Kashima Steelworks of Sumitomo Metal Industries, Ltd. (Kashima City,

NEDOL Process CC-ITSL Process (U.S.A.) IGOR+ Process (Germany)

First generation Processes in the ’40s

The PP

consists of five main facilities: the coal preliminary treatment unit, the liquefaction reaction unit, the coal-liquefied oil distillation unit,

Severe

the solvent hydrogenation unit, and the hydrogen production unit.

Coal preliminary treatment technology

Processes after the Oil Crisis

Severity of reaction

Liquefaction/reaction unit

Coal liquefied oil distillation unit Gas Separator

Atmospheric pressure distillation column

Circulation gas compressor Hydrogen

Slurry mixer Hydrogen compressor Slurry tank

170kg/cm2G (16.7MPa) 450@C

Preheating furnace

Slurry heat exchanger

Heating furnace

Fuel

Hydrogen

Fuel

Preheating furnace

110kg/cm2G (10.8MPa) 320@C

Residue Solvent booster pump

Stripper

Kerosene/ gas oil distillate Vacuum distillation column

Liquefaction reactor (3 units)

Separator

Drying/ pulverizing unit

Naphtha

High temperature separator

Let-down valve High pressure slurry pump

(Hydrogen-donor solvent)

Mild

Fig. 1 Relation between the severity of liquefaction reaction and the yield of coal-liquefied oil

Iron-base catalyst

Coal

Coal bin

Second generation

Small

Ibaraki), requiring nearly five years for completion.

Third generation

Yield of coal-liquefied oil

conducted operational studies on 9 coal grades under 72 sets of

As seen in the figure, the NEDOL

Solvent hydrogenation reactor

(Heavy distillate)

Fuel

Solvent hydrogenation unit

Fig. 1 Relation between the severity of liquefaction reaction and the yield of coal-liquefied oil 45

Clean Coal Technologies in Japan

3.Features of NEDOL Process The NEDOL Process is a coal liquefaction process developed

core process stages; and

exclusively in Japan. The process has integrated the advantages

(4) applicable to a wide range of coal grades, covering from sub-

of three bituminous liquefaction processes (Direct Hydrogenation

bituminous coal to low coalification grade bituminous coal.

Process, Solvent Extraction Process, and Solvolysis process), Catalyst

thus providing superiority in both technology and economics. Liquefaction catalyst

The advantages of the NEDOL Process include:

Hydrogenation catalyst

48.2 51.0 0.8 Other(wt%) Specific surface area (m2/g) 6.1 0.7~0.8 Size of pulverized catalyst [D50]( m)

(1) attaining high liquid yield under mild liquefaction reaction

Catalyst composition Fe (wt%)

conditions owing to the iron-based fine powder catalyst and to

S(wt%)

the hydrogen-donating solvent; (2) producing coal-liquefied oil rich in light distillate; (3) assuring high process stability because of the highly reliable

Ni-Mo/ Al2O3 190 0.7 Micropore volume (ml/g) 14.5 Mean micropore size (nm) Catalyst composition Fe (wt%)

Specific surface area (m2/g)

4.Typical reaction conditions of the NEDOL Process Liquefaction reaction Temperature Pressure

Solvent hydrogenation reaction

Slurry concentration 40wt%(dry coal basis) Slurry retention time 60min

450 C 170kg/cm2 G O

Kind of catalyst

Kind of catalyst

Hydrogen concentration in recycle gas 85vol%

320 C 110kg/cm2 G Ni-Mo-Al2O3 1 hr(-1) O

Pressure

700Nm3/t

Gas/slurry ratio

Iron-base fine powder catalyst Added amount of catalyst 3wt%(dry coal basis)

Temperature

LHSV

Gas/solvent ratio Hydrogen concentration in recycle gas

500Nm3/t 90vol%

5. Objectives and current progress of the pilot plant Objective of the development

Target

Achieved result

For the operation standard coal, 50 wt% or higher yield of light to medium oils, and 54 wt% of higher total yield.

With the operation standard coal, there were attained 51 wt% yield of light to medium oils, and 58 wt% of total yield.

2. Slurry concentration

40-50 wt% of coal concentration in slurry.

Stable operation was achieved at 50 wt% of coal concentration in slurry.

3. Added amount of catalyst

2-3 wt% (dry-coal basis) of added amount of iron sulfide-base catalyst. Operation was conducted in a range from 1.5 to 3 wt% of added amount of iron sulfide-base catalyst.

4. Continuous operation time

1,000 hours or more for the operation standard coal.

Continuous operation of 80 days (1,920 hours) was achieved with the operation standard coal.

5. Range of applicable coal grades

Three coal grades or more.

Operation was conducted with wide range of degree of coalification: namely, Adaro coal, Tanitohalm coal, and Ikejima coal.

1. Yield of coal-liquefied oil

6. Research and development schedule of the NEDOL Process pilot plants (Fiscal year)

~1983

1984

1985

1986

1987

1988

250 t/d PP design

1989

1990

1991

150 t/d PP design

1992

1993

1994

1995

1996

Construction

1997

1998

Operation

Core technology research and support study

7. Result of the research and development All the acquired data including the PP data, the basic research data,

developed materials and new processes are expected to

and the support study data were summarized in a technology

significantly influence development in other industries.

package preparing for practical application. At the Development and Assessment Committee meeting

Central control building Solvent hydrogenation unit

for Bituminous Coal Liquefaction Technology in the Assessment

Work

Group

of

the

Industrial

Technology Council, held on December 22, 1999, the

Fuel unit

Liquefaction reaction unit

NEDOL Process was highly evaluated: "The NEDOL Coal-liquefied oil distillation unit

Process is at the highest technology level in the

Coal preliminary treatment unit

world, and has reached the stage where worldwide Hydrogen production unit

diffusion is expected." Thus, the development of coal liquefaction technology in Japan has already exited

Storage unit

the research and development stage and entered the practical

application

stage.

Furthermore,

the

Fig. 3 Total view of NEDOL Process pilot plant (150 t/d)

References

1) Sadao Wasaka: "Bulletin of The Japan Institute of Energy", 78 (798), 1999 2) "Development of Coal Liquefaction Technology - A Bridge for Commercialization", Nippon Coal Oil Co., Ltd. 3) Haruhiko Yoshida: "Coal Liquefaction Pilot Plant", New Energy and Industrial Technology Development Organization 46

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Liquefaction Technologies)

3A3. Brown Coal Liquefaction Technology (BCL) In charge of research and development: New Energy and Industrial Technology Development Organization; Kobe Steel, Ltd.; Nissho Iwai Corp.; Mitsubishi Chemical Corp.; Cosmo Oil Co., Ltd.; Idemitsu Kosan Co., Ltd.; and Nippon Brown Coal Liquefaction Co., Ltd. Project type: Development of Brown Coal Liquefaction Technology; Development of Liquefaction Basic Technology; Coal Liquefaction International Cooperation Project; and other projects Period: 1981-2002 (21 years)

Outline of technology

1.Background and process outline Economically viable global coal reserves are expected to total

As shown in the figure, the BCL process has four stages: the slurry

about one trillion tons, about half of which is comprised of low-

dewatering stage where the water is efficiently removed from low-

grade coal such as sub-bituminous coal and brown coal. Coal

grade coal; the liquefaction stage where liquefied oil production

has a larger ratio of reserves to production (R/P) than that of oil

yield is increased by using a highly active limonite catalyst and the

and natural gas.

bottoms recycling technology; the simultaneous hydrogenation

For full-scale effective utilization of coal,

however, the effective use of low-grade coal is critical.

Low-

stage where the heteroatoms (sulfur-laden compounds, nitrogen-

grade coal contains a large amount of water but has an

laden compounds, etc.) in the coal-liquefied oil are removed to

autoignition property in a dry state compared with bituminous

obtain high quality gasoline, kerosene, and other light fractions;

coal and other higher grade coals. Consequently, brown coal

and the solvent deashing stage where the ash in coal and the

liquefaction technology development progressed aiming to

added catalysts are efficiently discharged from the process

contribute to a stable supply of energy in Japan by converting the

system.

difficult-to-use low-grade coal into an easy-handling and useful

In Asian countries, economic growth steadily increases energy

product, or by producing clean transportation fuels such as

demand, and countries possessing low-grade coal resources, such

gasoline and kerosene from the low-grade coal.

as Indonesia, anticipate commercialization of the technology.

Liquefaction stage

In-line hydrotreatment stage Sulfur recovery unit

Hydrogen

Sulfur

Recycle gas Recycle gas

Slurry dewatering stage

Off gas purification unit

Product gas (Fuel gas)

Reactor

Coal (Raw brown coal)

Hydrogenated light oil

Water Evaporator Fixed bed hydrogenation reactor

Distillation column

Hydrogenated medium oil

Solvent deashing stage

Preheater Slurry charge pump

Catalyst supply unit

Settler CLB (heavy oil) separator Sludge

CLB recycle

CLB

Solvent recycle DAO (deashed heavy oil) recycle

Fig.1 Flowchart of BCL

47

(Boiler fuel)

Clean Coal Technologies in Japan

2.Development objectives and technology to be developed A pilot plant (refer to the photograph) study conducted under the governmental cooperation of Japan and Australia investigated the subjects listed below. (1) Achieving high liquefied oil production yield: 50% or more (2) Achieving long-term continuous operation: 1,000 hours or more (3) Achieving high deashing performance: 1,000 ppm or less (4) Establishing a new slurry dewatering process Through four years of operation and study (19871990), all of the above targets were achieved. Furthermore,

scale-up

data

necessary

to

construct commercial liquefaction plants and expertise on plant operation was obtained through pilot plant operation.

Fig.2 50t/d Pilot plant (Australia)

During the study period, (the 1990s), however, a state of low oil prices and stable oil supplies existed worldwide

such as crushing property; a method to maintain catalytic activity

owing to a stable international oil supply and demand situation.

through the bottoms recycling technology; a simultaneous

Thus, further improvements in the economics of the coal

hydrogenation technology which significantly improves the quality

liquefaction process were requested, while cleaner liquefied oil

of coal-liquefied oil; and various improvements for increasing

was demanded owing to increased environmental concerns.

operational reliability. Through the development work, the study

Accordingly, the study team constructed a bench-scale plant (0.1

established the improved BCL process (Improved Brown Coal

t/d) in the Takasago Works of Kobe Steel, Ltd. to conduct a study

Liquefaction Process, refer to the flowchart on the preceding

for improving the process.

The study developed: a limonite

page) that significantly improves the economics, reliability, and

catalyst which has extremely high activity compared with existing

environmental compatibility of the brown coal liquefaction

liquefaction catalysts, and which has superior handling properties

process.

3.Progress and result of the development On the basis of a memorandum on cooperative coal liquefaction

engineers through instruction and supply of liquefaction testing

research between the Agency for the Assessment and

equipment.

Application of Technology of Indonesia and New Energy and

In 1999, the study team selected three candidate sites for the

Industrial Technology Development Organization, the study team

liquefaction plant in Indonesia, and carried out a feasibility study

carried out surveys and liquefaction tests of the low-grade coal in

on coal liquefaction, including an economic evaluation.

Indonesia beginning in 1994, in addition to screening of

feasibility study revealed that coal liquefaction would be

candidate coals for liquefaction.

economically feasible only if the price of oil did not decrease.

Furthermore, the team

The

endeavored to increase the technical abilities of the Indonesian

4.Issue and feasibility of practical application Supported by steady economy growth, Asian countries exhibit

the energy security of Japan, expectations are high for the

rapidly increasing energy demand. Although currently a net oil-

practical application of brown coal liquefaction technology

exporting country, Indonesia is expected to become a net oil-

utilizing unexploited low-grade coal.

importing country by around 2010. Since the stable supply of

viewpoint, the possibility of practical application of the technology

energy from Asian countries to Japan significantly contributes to

is large.

References

1) Shunichi Yanai and Takuo Shigehisa: CCT Journal, vol.7, p 29 (2003) 2) Report of the Result of the International Coal Liquefaction Cooperation Project (Cooperative Study of Development of Low Grade Coal Liquefaction Technology) (2003)

48

From a medium-term

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Liquefaction Technologies)

3A4. Dimethylether Production Technology (DME) In charge of research and development:DME Development Co., Ltd. (The company was established in 2001 in collaboration of following-listed ten companies aiming to establish the technology of direct synthesis of DME.), JFE Holdings Co., Ltd.; Nippon Sanso Corp.; Toyota Tsusho Corp.; Hitachi Ltd.; Marubeni Corp.; Idemitsu Kosan Co., Ltd.; INPEX Corporation; TOTAL S.A.(France); LNG Japan Co., Ltd.; and Japan Petroleum Exploration Co., Ltd.(JAPEX) Project type: National Grant project of "Development of Technology for Environmental Load Reducing Fuel Conversion" of the Agency of Natural Resources and Energy of the Ministry of Economy, Trade and Industry Period: 2002-2006 (5 years)

Outline of technology

1.Background and process outline Dimethylether (DME) is a clean energy source of low

Currently DME is produced by dehydration of methanol

environmental load, generating no sulfur oxide or soot during

amount of about 10 thousand tons a year in Japan, and 150

combustion. Owing to the non-toxicity and easy liquefaction

thousand tons a year in the world. The main use of DME is spray

properties, DME is easy in handling, thus it can be used as

propellant. If the supply of DME is available in large amount at

domestic-sector fuel (substitute for LPG), transportation fuel

low price, DME is expected to be used as fuel in wide fields

(diesel vehicle, fuel cell automobile), power plant fuel(thermal

owing to the above-described superior properties.

at

plant, cogeneration plant, fuel cell), and raw material for chemical products. 2.Development object and technology to be developed The object of the study is the development of direct synthesis process of DME from syngas (mixed gas of H2 and CO),

(1) 3CO+3H2 CH3OCH3+CO2 (2) CO+2H2 CH3OH (3) 2CH3OH CH3OCH3+H2O

(reaction (1)). The DME production through the dehydration of methanol, (reaction (3)), is the existing technology. The plant scale under actual operation, however, is rather small, and the scale up is an

100 H2+CO conversion [%]

issue to produce DME commercially for fuel service. In addition, the equilibrium conversion of the methanol synthesis reaction (2) is relatively small as show in Fig.1. On the other hand, in the direct DME synthesis reaction (1) because the limitation of equilibrium of methanol synthesis is avoidable the conversion is higher than that of methanol synthesis. The reaction formulae relating to the direct DME synthesis are given below. The equilibrium conversion of methanol synthesis

(1) 3CO + 3H2

60 40 (2) CO + 2H2

20

and of direct DME synthesis is given in Fig. 1.

CH3OCH3 + CO2

80

CH3OH

Since the direct synthesis gives maximum conversion at H2/CO=1 of the syngas composition, the process is suitable for

0.0

the syngas produced from coal gasification (H2/CO=0.5-1). The

0.5

1.0

1.5

2.0

2.5

H2/CO ratio [-]

targets of the development study include the following.

49

3.0

Clean Coal Technologies in Japan

3.Progress and result of the development The development of direct synthesis process has been led by

with the aid of the Ministry of Economy, Trade and Industry. The

JFE (ex-NKK). The first step is the search of direct synthesis

construction of demonstration plant finished in November 2003,

catalyst. The second step is the small bench plant (5 kg/d). The

and the operation is scheduled to start at the end of 2003 to

third step is the pilot plant (5

ton/d) 1)2) constructed

conduct five runs of long period continuous operations (2 to 3

with the aid of

months) until 20063).

the Ministry of Economy, Trade and Industry. The fourth step is the demonstration plant (as large as 100 ton/d) constructed also

Photo 1 5 ton/d pilot plant

Photo 2 100 ton/d demonstration plant

4.Issue and feasibility of practical application DME is already utilized as a fuel at inland area of China in small

the future, however, they are supposed to switch the raw material

scale. In Japan, activities toward the practical application of DME

to coal which is larger in reserves quantity than natural gas.

as fuel are in progress at: DME International Co., Ltd. which was

In natural gas case, the CO2 obtained from CO2 separation

established by the same ten companies of DME Development

column is returned to syngas generation furnace, but the same is

Co., Ltd. aiming at the study for Commercialization of DME;

released to atmosphere in coal case. When the CO2 storage

Japan DME Co., Ltd. which was established by four companies,

technology in long term is established in future, the coal based

namely, Mitsubishi Gas Chemical Co., Inc., Mitsubishi Heavy

process can provide purified CO2 without any additional facilities.

Industries, Ltd., JGC, and Itochu Corp.; Mitsui & Co., Ltd. and

Also in western world, DME draws attention in wide fields as a

Toyo Engineering Corp.; (the last two adopted the methanol

new fuel. They however, expect mainly to use in diesel vehicles

dehydration process). These activities aim to supply DME

to fully utilize the advantageous characteristic of no-generation of

product in 2006. All of them plan to use natural gas as the raw

soot.

material, because natural gas requires small initial investment. In

Purge gas

CO2

CO2

Non-reacted gas

Natural gas

DME

Coal mine methane Coal Oxygen Steam Liquid/gas separator

Reaction condition 250~280OC 3~7Mpa CO,CO2,H2 Synthesis gas generation furnace

Gas purification column

Methanol DME synthesis reactor

CO2 separation column

DME purification column

Fig. 2 Typical process flow diagram of DME direct synthesis plant from coal or natural gas

References

1) Tsunao Kamijo et al.: Lecture papers of The 8th Coal Utilization Technology Congress, Tokyo 1998, pp.194-205 2) Yotaro Ono et al.: Preprint for the lectures of the 30th Petroleum and Petrochemical Discussion Meeting, Tokyo 2000, pp.26-29 3) Yotaro Ono: Japan DME Forum Workshop 2002, Tokyo, pp.113-122 50

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Pyrolysis Technologies)

3B1. Multi-Purpose Coal Conversion Technology (CPX) In charge of research and development: Center for Coal Utilization, Japan; Nippon Steel Corporation; NKK Corporation; Kawasaki Steel Corporation; Sumitomo Metal Industries, Ltd.; Kobe Steel Ltd.; Ube Industries, Ltd.; Idemitsu Kosan Co., Ltd.; Nippon Steel Chemical Co., Ltd. Project type: Subsidized coal production/utilization technology promotion Period: 1996-2000 (5 years) *Coal Flash Pyrolysis Process: CPX stands for Coal Pyrolysis suffixed with X meaning diversified products. Outline of technology

1.Technological features In an attempt to further expand versatile utilization of coal, this

4. Efficient separation of coal ash

project is intended to develop a multi-purpose coal conversion

- Coal ash is discharged from the gasifier as molten slag and

technology excellent in efficiency, economy, and environment-

then granulated with water.

friendliness, mainly for the purpose of manufacturing medium-

5. Diversified utilization of products available

calorie gas as industrial fuel and liquid products as raw materials

- Among products, gas can be used as industrial fuel, liquid (light

for chemicals.

oil/tar), as raw materials for chemicals, solid char, as fuel or a

The features of this process are as follows:

reducer, and slag, as an ingredient of cement.

1. Moderate operational conditions

- The heating value of gas produced from the process is as high

- The pyrolysis reactor works at a temperature of as low as 600-

as about 3,500kcal/Nm3.

950 C.

- The yield of gas and liquid (light oil/tar) combined is 70% or

- The reaction pressure of lower than 1Mpa is much lower than

more of coal input.

several to tens of Mpa at which the coal liquefaction and hydro-

6. Controllable yield of products

gasification processes operate.

- A change in pyrolysis temperature (600-950 C) or coal kind

2. High overall thermal efficiency

allows product yields to be correspondingly changed.

O

O

- Flash pyrolysis of coal is combined with partial recycle of generated char to gasify more char, thereby improving the thermal efficiency of the process. 3. Workable with multiple kinds of coal - The dependence on cheaper classes of coal from subbituminous to highly volatile bituminous coal for the main material enables gas/tar to be obtained in large quantities.

Heat recovery Cyclone Tar cooler Gas purification

Scrubber Coal

Pyrolysis reactor

Gas

Char hopper

Crushing/drying Char heat recovery

Steam

Decanter

Separator

Char gasifier

Tar

Char

Slag Fig.1 Process Flow Sheet 51

Clean Coal Technologies in Japan

2.Summary of technology This process is characterized by higher overall thermal efficiency

solid product (char) separated at the cyclone is recycled to the

achieved with a compact low-pressure char/oxygen gasification

char gasifier and the remaining is offered as a product after heat

system, which combines flash pyrolysis of coal and partial

recovery. Heat is recovered from the gas containing pyrolysis

recycle of pyrolysis product char to use sensible heat of char gasification

product

gas

as

a

heat

source

for

flash

heating/pyrolysis reaction of pulverized coal (Fig.1).

The

products until it cools down to about 350 C through indirect heat O

exchange with thermal oil while tar passes the venture scrubber/tar cooler to be recovered.

entrained-bed coal flash pyrolysis has been developed as a

Pyrolysis gas is made

available for use as industrial-purpose fuel gas after purification

process which not only produces more high value-added gas and

such as through light oil (BTX) recovery and desulfurization.

liquid (tar and oil) possessing a coke oven gas (COG)-equivalent

At the pilot plant (Photo 1) built within Yawata Works of Nippon

heating value but also supplies heat necessary for pyrolysis.

Steel Corp., tests were conducted mainly with a view to the

Pulverized and dried coal (of about 50 m in grain size) is blown

evaluation/verification of process component/total system

into the pyrolysis reactor and mixed with hot gas at 600-950 C O

technologies

and several atm, with 2 seconds as its reaction time, to be flashheated/pyrolyzed.

to

establish

the

technological

basis

for

commercialization as well as obtain data which would help

In terms of heat necessary for pyrolysis

design an actual plant (1,000t/d) and evaluate its economy. In

reaction, part of pyrolysis product solid char is recycled to the hot

two years from 1999, it was test-run 10 times in all, achieving a

gas generation section (char gasifier) to be partially oxidized by

maximum 210-hour stable continuous operation.

oxygen and steam, thus allowing an about 1,500-1,600 C stream

During the

O

time, the aforementioned features were verified, assuring the

of gas mainly composed of CO and H2 to generate so that

controllability of products at a pyrolysis temperature (Fig.2)

sensible heat of the gas is used for the supply of such heat. The

before the completion of process data taking.

pyrolysis reactor employs an up-flow system where the hot gas generated at this gasifier is fed from the lower part of the reactor and, after pyrolysis coal is mixed, leaves the system at the reactor’s upper part together with pyrolysis products. Part of a

Photo 1 Full View of Pilot Plant Fig. 2 Relationship between Pyrolysis Product Yield and Pyrolysis Temperature PDU:7t/d test equipment

References

1) Hiroyuki Kozuru et al.: Advanced Clean Coal Technology Int’l Symposium (2001) 2) Masami Onoda et al.: 10th Annual Conference on Clean Coal Technology abstracts (2000) 3) Shigeru Hashimoto et al.: Pittsburgh Coal Conference (2000) 52

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Pyrolysis Technologies)

3B2. Coal Flash Partial Hydropyrolysis Technology In charge of research and development: The Center for Coal Utilization, Japan; the New Energy and Industrial Technology Development Organization; the National Institute of Advanced Industrial Science and Technology; Nippon Steel Corporation; Babcook Hitachi K.K.; Mitsubishi Chemical Corporation Project type: Subsidized coal production/utilization technology promotion project Period:1. Coal utilization next-generation technology development survey/1996 through1999 (4 years) 2. Coal utilization commercialization technology development/2003 through 2008 (6 years)

Outline of technology

1.Objective of technology Clean Coal Technology-related technology development having a

be evolved such as into Integrated Gasification Combined-Cycle

perspective of a single industry in pursuit of a single product is

(IGCC) power generation, indirect liquefaction (GTL), and

reaching its limits in terms of efficiency and economy, calling the

chemicals while co-producing light oil as chemicals and fuel.

necessity to develop such innovative technologies as could

The realization of a coal-based cross-industrial composite project

completely change what energy and material production should

(led by electric power/chemistry/steel) with this technology as its

be.

core will hopefully bring a dramatic improvement to total energy

Coal Flash Partial Hydopyrolysis Technology is a technology

utilization efficiency.

which causes rapid reaction to pulverized coal under high pressure (2-3Mpa) and in a moderate hydrogen atmosphere to highly efficiently obtain, from one reactor, synthetic gas easy to 2.Outline of technology Fig. 1 shows a total process flow of this technology. At the partial

concentration (H2 in hot gas and recycle H2 combined). At that

oxidation section of a coal flash partial hydropyrolsyis reactor,

time, hot gas from the partial oxidation section also functions as a

pulverized coal and recycled char are gasified with oxygen and

source of the reaction heat required at the reforming section. At

steam at a pressure of 2-3MPa and at a temperature of 1,500-

the reforming section, a hydrogenation reaction adds H2 to

1,600 C to give hot gas mainly composed of CO and H2. At the

primary pyrolysis, such as tar released from pulverized coal,

reforming section directly connected through a throat to the

changing heavy tar-like matter to light oil. The gas, light oil, and

partial oxidation section, pulverized coal is injected together with

char produced at the partial hydropyrolysis reactor follow a

recycled H2 into the hot gas stream from the partial oxidation

process where, after char separation at the cyclone and

section to complete the reforming reaction (partial hydropyrolysis)

subsequent sensible heat recovery, synthetic gas (syngas)

in a moment under the condition of 2-3MPa in pressure, 700-

should be formed by way of oil recovery, desulfurization, and

900 C in temperature, and about 30-50% in hydrogen

other gas purification processes. Part of syngas is converted into

O

O

Decarboxylation

Shift conversion to H2 Heat recovery

Gas purification

Syngas

Chemicals

IGCC fuel

GTL fuel

City gas

Reforming section Coal reforming reaction Gas

Heat H2 concentration 30-50%

Coal

Partial hydropyrolysis reactor

Char

Heat

Coal Light oil

Hot gas

Light oil

Partial oxidation section

Steam Slag Fig. 1 Process Flow 53

Chemicals

Fuel for power generation

Clean Coal Technologies in Japan

H2-rich gas in the course of shift reaction and decarboxylation

required at the reforming section, providing high energy

(CO2 recovery) and, after pre-heated via heat exchange, recycled

conversion efficiency.

to the partial hydropyrolysis reactor’s reforming section. A final

2. Flexible productivity: The reforming section temperature as

syngas product is characterized by its main composition of H2,

well as the amount of hydrogen injected can be controlled so as

CO, and CH4 as well as high hydrogen contents at H2/CO 1 and

to freely change the gas/oil composition and output ratio, thereby

used as source gas of IGCC, GTL, and chemicals. Light oil is

flexibly responding to consumers’ needs.

mainly composed of aromatic compounds with 1-2 rings such as

3. Economy: For the purpose of syngas production, gas

benzene and naphthalene, finding its application as chemicals or

production cost may be reduced through its deduction by co-

fuel for power generation.

produced high value-added oil.

This technology is roughly featured as follow: 1. High-efficiency: The sensible heat of hot gas generated at the partial oxidation section is effectively used as a source of heat

3.Progress status of development 1) Basic partial hydropyrolysis test (1996 through 1999, 1kg/day)

3) Pilot plant test (2003 through 2008, 20t/day)

Using a small-scale test unit, the pyrolysis behavior of coal under

Tests are conducted, using a pilot plant having its thermally self-

target conditions of this technology was reviewed, confirming that

supportable reactor together with other ancillary process units, to

the

have forecasts for a demonstration unit (up to 1,000t/day) as the

hydropyrolysis

of

primary

tar

released

from

flash

heating/pyrolysis reaction of coal successfully proceeded.

next step.

2) Process development unit (PDU) test (2000 through 2003, 1t/day *NSC in-house research) Using a reforming/partial oxidation-integrated PDU test unit, the basic performance of a partial hydropyrolysis reactor as the core of this technology was evaluated, clarifying the reaction in the reactor.

Table 1 Development Subjects for Pilot Plant Tests Technology to be developed

R&D items

Verification of the reaction in the partial hydropyrolysis reactor/ establishment of reactor control technology

- Quantification of partial hydropyrolysis reactor reaction - Establishment of reactor conditions for optimum transition zone formation - Establishment of high-efficiency gasification (partial oxidation section) operational conditions

Development of process/factor technologies

- Establishment of technology to separate/recover char from gas - Establishment of technology to recover heat from gas co-existent with oil

Total system evaluation, etc.

- Establishment of long-hour continuous operation technology - Establishment of a scale-up approach for demonstration unit design

Table 2 Development Schedule 2003

2004

2005

2006

Pilot plant test Design/production/construction works Studies by testing Studies by disassembly Assistant studies

References

1) H. Shimoda et al, 10th Annual Conference on Clean Coal Technology lecture collection, p296, 2000 2) H. Yabe et al, 2nd Japan-Australia Coal Research Workshop Proceedings, p257, 2002 54

2007

2008

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Powdering, Liquefaction, and Common Use Technologies)

3C1. Coal Cartridge System (CCS) Outline of technology

1.Outline of system The CCS (Coal Cartridge System) is a system where, on behalf

from 1985, to demonstration tests at manufacture/supply and

of medium-/small-lot consumers using several thousands of tons

combustion bases, in an attempt to establish the reliability of

of coal a year, for whom it is difficult to import overseas coal

CCS as well as coal blending and suitable quality requirements

constantly for themselves, overseas coal is collectively imported

for CCS standard coal production. As a result, the first Japanese

and blended into qualities suitable for each such consumer to be

CCS center (with a capacity to produce 200 thousand tons a

supplied as pulverized coal.

year) was built in 1991 and then 2 CCS coal-dedicated boilers

This technology was subjected, under a 3-year program starting

started operation.

2.Characteristics of system

3.Technical data

Common systems of pulverized coal firing, before burning the coal

Attributes of CCS coal in general are shown in (Table 1)

stored at its stockyard, pulverize it with a mill for the supply to a

(Table 1) Attributes of CCS Coal in General

boiler, but in CCS, after coal is pulverized at a production/supply

Brand Referential control Raw coal for mixture Total moisture Wt% AR Heating value kcal/kg * Moisture Wt% dry Ash Wt% dry Volatiles Wt% dry dry Fixed carbon Wt% Fuel ratio daf Carbon Wt% daf Hydrogen Wt% daf Nitrogen Wt% daf Oxygen Wt% daf Sulfur Wt% dry Total sulfur Wt% dry Grain size -200mest

facility, all processes are to be completed within a closed system of gaseous-phase carriage, from loading onto tank lorries to deacquisition to consumers’ coal silos and then supply to boilers.

Ultimate analysis

This not only eliminates the problem of coal dust scattering, thereby keeping the environment clean, but also enables smooth operation to be realized through easier control of powder flows and, therefore, fluctuations in boiler loads.

Proximate analysis

In behalf of consumers, this also advantageously requires no mill installation, dispenses with a coal yard since coal can be stored in a silo, and lessens equipment investment due to the compact equipment configuration, thus leading to labor saving and the better environment. CCS is, as mentioned above, a coal utilization system of improved coal handling with a closed powder carriage system of pulverized coal.

A 3 kinds 2.9 6490 0.0 12.1 39.6 48.3 1.22 80.30 5.80 1.60 11.80 0.48 0.45 84.5

B 3 kinds 2.8 6480 0.0 12.4 39.5 48.1 1.22 80.00 5.80 1.50 12.40 0.47 0.43 78.9

4.Process flow Pulverized coal collection bag filter

(Fig.1) shows a flow sheet and system outline of the CCS coal production/supply facility.

Screw conveyor

Raw coal bunker

Magnetic separator

Mill supply hopper

Volumetric coal feeder

Chain conveyor

Product silo

Product silo

Table feeder

Truck scale

Pulverizer Fuel gas

Product silo

Air heater

Seal gas blower

Kerosene Gas cooler Fuel air blower

Recycle gas blower

Recycle gas line

Cooling tower Industrial water tank

Nitrogen generator

Outline of equipment 1 Raw coal hopper 20m3x1 unit 2 Raw coal bunker 400m3/Hx2 units 3 Pulverizer 25t/Hx2 units

4 Bag filter 67,500Nm3/Hx1 unit 5 Product silo 680m3x4 units 6 Truck scale 4 units 7 Nitrogen generator 350Nm3x1 unit

(Fig.1) CCS Coal Production/Supply Facility 55

tank

Raw coal hopper

Conveyor

Product silo

C 2 kinds 2.7 6490 0.0 12.1 35.6 50.3 1.41 82.00 5.90 1.50 10.50 0.45 0.41 83.50

Clean Coal Technologies in Japan

3C2. Coal Slurry Production Technology Outline of technology

1.Outline of coal slurry Since coal is a solid material with some problem, requiring more

spontaneous firing or dust scattering and can advantageously be

complex handling than a fluid does, environmental measures

handled as an easy-to-treat liquid. Conventional coal slurry using

against dust, and spacious land for a coal yard, its slurry form

no additive can be piped but, due to its water contents of about

has been noted as a means to make heavy oil-comparative,

50%, is poor in long-run stability, requiring dehydration before firing.

clean use of coal. Coal slurry fuel is found as COM (coal oil

High-concentration CWM can now, as a result of studies on the

mixture) prepared by adding heavy oil to coal to give slurry, aside

particle size distribution of coal and a dispersant and other additives

from CWM (coal water mixture), a mixture of coal and water.

development, be kept fluid as well as stable even if less water is

COM, a combination of coal and heavy oil convenient for burning,

added and, therefore, directly burnt without being de-watered. Only

was earlier than CWM to be technically reviewed but failed to

a slight amount of additives added realize stable coal-water slurry in

prevail after all, rather bottlenecked by the necessity of heavy oil.

which coal particle of a certain size distribution are uniformly

CWM is a mixture of water and coal, raising no problem of

dispersed with their weight concentration of about 70%.

2.Characteristics of high-concentration CWM Typical characteristics of high-concentration CWM (Chinese coal

3) Particle size distribution

CWM) are shown in (Table1) below.

For higher concentration/stability of CWM, pulverized coal sizes should preferably be distributed over a wide range rather than

(Table 1) Characteristics of High-Concentration CWM Coal concentration (wt%) Higher heating value (kcal/kg) Lower heating value (kcal/kg) Apparent consistency (mPa-s) Specific gravity(-) Ash content (wt%) Sulfur content (wt%) Grains of 200 mesh or less (%)

sharply distributed. Ordinary particle sizes used are roughly as

68~70 5,000~5,200 4,600~4,800 1,000 1.25 6.0 0.2 80~85

shown in (Table 2). (Table 2) Grain Size Distribution of High-Concentration CWM Maximum grain size

150~500 m

Average grain size

10~20 m

Grains of 74 m or less

80% or more

Fine grains of several micrometers or less

Around 10%

1) Coal type

4) Rheological characteristics

As a general trend, high-carbonization, low-inherent moisture

CWM’s fluidity has characteristics of a non-Newtonian fluid but

(about 5% or less in approximate analysis), and less-oxygen

can be construed as a near-Bingham fluid’s.

content (about 8% or less in ultimate analysis) coal is suitable for

characteristics also changes, depending upon, such as the coal

high-concentration CWM.

kind, concentration, additive, and flow state.

2) Additives

viscosity is roughly 1,000mPa-s (at room temperature and shear

Additives consist of dispersants and stabilizers.

The fluidity The apparent

A dispersant

speed of 100/s).

functions to disperse coal particles into slurry, using electrostatic

5) Heating value

repulsion effects or steric repulsion effects and sodium sulfonate of

The heating value depends upon that of coal used. An average

naphthalene, polystyrene, polymethacrylate, polyolefine, and the like

lower heating value is 4,600-4,800kcal/kg.

is used here. Additives including CMC and xanthan gum are used to prevent coal particles in slurry from settling for stabilization. 3.Manufacturing process of high-concentration CWM Production of high-concentration CWM

can

be

achieved

Reception/storage of feed coal

by

Smashing

pulverizng coal into a particle size

distribution

suitable

for

CWM, selecting correct additives (a dispersant and stabilizer), and appropriately water,

blending

and

additives

coal,

Hot wet smashing Cold wet smashing De-watering

Coal smashing and mixing with water/additives to be done within a pulverizer

Smashed coal/water/additives mixing

Dry smashing

Smashed coal/water/additives mixing

to

manufacture high-concentration, low-viscosity, high-stability, and good-quality CWM. A block flow of CWM manufacturing process is shown in Fig.1.

Enhancement of mixing CWM storage CWM shipment

(Fig.1) CWM Manufacturing Process 56

Coal Water Mixture (CWM)

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Powdering, Liquefaction, and Common Use Technologies)

3C3. Briquette Production Technology Outline of the technology

1.Background The global warming issue caused by CO2 and other substances

To this point, the briquette production technology is an

has become world concern in recent years. To protect forestry

environmental countermeasure technology, or a clean coal

resource as a major absorbent of CO2, control of ever-increasing

technology, providing the stable supply of briquettes to contribute

deforestation along with the increase in consumption of wood fuel

to the prevention of flood damage and the conservation of

such as firewood and charcoal is an urgent issue. Thus, the

forestry resource.

development of substitute fuel for charcoal is emphasized.

2.Carbonized briquettes (1)Process outline

(2)Carbonization stage

Process for producing briquettes by coal carbonization has the

The raw material coal (10% or lower surface water content, 5-50

carbonization stage and the forming stage. Figure 1 shows the

mm of particle size) is preliminarily dried in the rotary drier. The

basic process flow.

gas leaving the drier passes through multi-cyclone to remove

The carbonization stage has the internal heating low temperature

dust before venting to atmosphere. Figure 2 shows the cross

fluidized bed carbonization furnace (about 450 C of carbonization

sectional view of the internal heating low temperature fluidized

temperature) to produce smokeless semicoke containing about

bed carbonization furnace which performs most efficient

20% of volatile matter. The carbonization furnace has a simple

carbonization of semicoke while retaining about 20% of volatile

structure having no perforated plate and agitator so that the

matter in the semicoke.

operation and the maintenance of the furnace are easy.

The preliminarily dried

In the forming stage, the smokeless semicoke and auxiliary raw

raw

materials (hydrated lime and clay) are thoroughly mixed at a

charged to the middle

predetermined mixing ratio. After pulverizing, the mixture is

section of the furnace,

blended with a caking additive while adding water to adjust the

and

water content of the mixture.

The mixture is kneaded to

fluidization carbonization.

uniformize the distribution of caking additive, and to increase the

The product semicoke is

viscosity to attain an easy-forming condition. Then the mixture is

taken out from top of the

introduced to the molding machine to prepare briquettes. The

furnace together with the

briquettes are dried and cooled.

carbonization gas.

O

material

is

coal

is

subjected

to

The

semicoke is separated from the carbonization gas by the primary cyclone and the secondary cyclone. After cooled, the semicoke

Raw Coal

is

transferred

to

Fig. 2 Cross sectional view of carbonization furnace

the

stockyard, and the carbonization gas is supplied to the Drying

combustion furnace lined with refractory, where the carbonization Coalite

Crushing

gas is mixed with air to combust. Cyclon

Carbonizing

Kneading

The generated hot gas is

introduced to the raw material coal drier and to the succeeding briquette drier to use as the drying heat source of preliminary

Desulfurizer Binder

heating of the raw material coal and the drying heat source of the

Water

formed oval briquettes. (3)Forming stage

Mixing

The semicoke (Coalite) produced in the carbonization stage is the briquette raw material containing adequate amount of volatile

Briquetting

Briquette

matter, small amount of ash and sulfur, and emitting no smoke and no odor. The semicoke as the main raw material is mixed

Drying

with hydrated lime (sulfur fixing agent), clay (assistant for Fig. 1 Process flow of briquette production

forming), and a caking additive.

57

Clean Coal Technologies in Japan

To attain uniform composition and improved formability, the mixed raw material is fully kneaded. Forming of the mixture is carried out using the roll molding machine at normal temperature and under about 1,000 kg/cm (300-500 kg/cm2) of line pressure. Photograph 1 shows the forming state. The formed briquettes are dried in the continuous drier to become the product. Since the semicoke as the raw material of briquettes has strong ignition property and readily ignites in the furnace, the drier is requested to operate at low temperature level. The drier is designed considering the temperature-sensitive operation. Photo 1 Formed briquettes

3.Bio-briquettes Bio-briquettes are a kind of solid fuels, prepared by blending coal

the low temperature region (200-400 C) does not completely

with 10-25% of vegetable matter (biomass) such as wood

combust. To the contrary, bio-briquettes combust simultaneously

bagasse (strained lees of sugar cane), straws, and haulms of

the low ignition point biomass which entered between coal particles

corn, further with desulfurizing agent (Ca(OH)2) by an amount

with the coal, which assures the combustion of volatile matter

corresponding to the sulfur content in the coal. Owing to the high

released in the low temperature coal combustion region. As a

t/cm2),

O

the coal particles and the fibrous

result, the amount of generated dust and soot significantly reduces.

vegetable matter in the bio-briquette strongly interwind and

2. The bio-briquettes prepared by adding 15-20% of biomass to

adhere to each other. As a result, they do not separate from

coal gives significantly short ignition time to improve the ignition

each other during combustion, thus attaining combined

property.

combustion of the vegetable matter having low ignition

caking property so that the aeration between briquettes is

temperature and the coal.

secured during continuous combustion in a fireplace, giving

pressure briquetting (1-3

The combined combustion gives

In addition, the bio-briquettes have low expansion

favorable ignition and fuel properties, emits very small amount of

favorable combustion characteristic.

dust and soot, and generates sandy combustion ash to leave no

Consequently, the bio-briquettes have superior combustion-

clinker. Furthermore, since the desulfurizing agent also adheres

sustaining property, and do not die out in a fireplace or other heater

to the coal particles, the agent effectively reacts with the sulfur in

even when air rate is decreased to slow down the combustion rate,

the coal to fix about 60-80% of the sulfur into the ash.

which makes the adjustment of combustion rate easy.

Applicable coal grades are many, including bituminous coal,

3. Since fibrous biomass enters between coal particles, there is

subbituminous coal, and brown coal. In particular, the bio-briquettes

no fear of clinker-lump formation during combustion caused by

utilizing low grade coal containing large amount of ash and having

adhesion of fused ash in coal, thus the ash falls in sandy form

low calorific value gives large effect of coal-cleaning, thus the bio-

through grate.

briquette technology is an effective technology to produce clean fuel

combustion state. Furthermore, since no clinker is formed, ash

for household heaters and industrial small boilers.

contains very small amount of unburnt coal.

(1)Production flow of bio-briquettes

4. The bio-briquettes are formed under high compressive force.

Figure 3 shows the basic flow of bio-briquette production. The

Accordingly, the desulfurizing agent and the coal particles strongly

coal and the biomass as the raw materials are pulverized to

adhere to each other, and they effectively react during combustion.

about 3 mm or smaller size, which are then dried. The dried

With the addition of desulfurizing agent at about 1.2-2 of Ca/S

mixture is further mixed with a desulfurizing agent (Ca(OH)2).

ratio, 60-80% of the sulfur in coal is fixed in the ash.

Therefore, aeration is secured to stabilize the

The mixture is formed by compression molding in the high pressure briquetting machine.

Coal

Powder coal may be applied

Biomass

without subjected to pulverization. A small amount of binder may be added to some coal grades.

Drying

Pulverization

The production process does not contain high temperature operation, and has a structure centering on the dry high pressure

Drying Pulverizing

briquetting machine. The process is simple facility flow which is Deodorant

safe and which does not require skilled operational technique.

Caking additive

Owing to the high pressure briquetting method, the coal particles

Caking additive may be required depending on the coal grade.

and the biomass strongly interwind and adhere to each other, thus the process produces rigid formed coal which does not

Mixing

separate their components during combustion. High pressure briquetting

(2)Bio-briquette characteristics 1. Compared with the coal direct combustion, the bio-briquette combustion decreases the generation of dust and soot by one fifth to one tenth.

Bio-briquette

The coal direct combustion gives increased

generation of dust and soot because the volatile matter released in

Fig. 3 Basic flow of bio-briquette production 58

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Powdering, Liquefaction, and Common Use Technologies)

3C4. Coal and Woody Biomass Co-firing Technology In charge of research and development: New Energy and Industrial Technology Development Organization; the Chugoku Electric Power Co., Inc.; Hitachi, Ltd.; Babcook-Hitachi K.K. Project type: High-efficiency biomass energy conversion technology development Period: 2001-2003 (3 years)

Outline of technology

1.Background As part of measures to arrest global warming, industrially

an existing mill (pulverizer) and grind it for the combustion of

advanced countries are practicing mechanisms to promote the

pulverized coal-biomass mixture fuel in a boiler, using the

adoption of power generation using renewable energy. One of

existing burner.

them is the RPS (Renewable Portfolio Standard) System. Since

equipment and, therefore, less cost while there is a problem that

April 2003, the "Special Measures Law concerning the Use of

a mixture of more than several % biomass causes the mill’s

New Energy by Electric Utilities (RPS Law)" has bee enacted,

power consumption to sharply increase due to the difficulty in

obligating electric utilities to use a certain amount of new energy

grinding woody biomass with ordinary pulverizers.

for power generation. The normal usage (obligation amount) of

method is to establish a biomass-dedicated mill.

new energy for electricity is assumed to increase from 3.3GkWh

equipment cost higher than the former, this method is

in 2003 to 12.2GkWh in 2010. What is defined as new energy

advantageous not only because the ratio of mixture may be

includes biomass fuel.

made higher but also because the amount of NOx generated can

Co-firing of coal and woody biomass in the power generation

be reduced.

sector, though already under way in U.S. and European

Here, the latter method for which technology development is

countries, is a novel trial facing a variety of technological

under way, commissioned by the New Energy and Industrial

problems. For pulverized coal-fired boilers, there are roughly two

Technology Development Organization (NEDO), is introduced.

This method requires less adaptation of

methods of co-firing. One is to simply input woody biomass into

Combustion test/evaluation

Woody biomass technology investigation Boiler

Exhaust gas treatment

Mill Coal Burner Woody biomass

Separation Storage Drying

Grinding

FS for commercialization

Pre-treatment technology development

Fig.1 Coal/Woody Biomass Co-Firing System and Practiced Items

59

The other Despite the

Clean Coal Technologies in Japan

2.Development target

3.Technologies to be developed

(1)Co-firing ratio of woody biomass: 5-10%

(1)Woody biomass pre-treatment technology mainly of grinding

(2)Clearance of current regulatory environmental limits

(2)Woody

(3)Existing coal thermal power plants-comparable power

burner/biomass-dedicated burner)

biomass

combustion

technology

(co-firing

generation efficiency: A decrease in net thermal efficiency to be made 0.5% or less with the woody biomass co-firing ratio of 5% (on a calorific base). Bag filter Burner

Mill [1]

To stacks

Bin

Biomass

Furnace

Hopper Feeder Hopper Cyclone Feeder

Heater

Crusher

Blower

Drier

Mill [2]

Fig.2 Pilot Scale Test Equipments

4.Development in progress and results This project, under way jointly at the Chugoku Electric Power

by NEDO, is now at the stage of FS for the evaluation of pilot

Co., Inc., Hitachi, Ltd., and Babcook Hitachi K.K., commissioned

plant test combustion results toward commercialization.

R&D Schedules 2001

2002

2003

2004

Coal/woody biomass co-firing technology R&D (a business commissioned by NEDO) Development of component technologies for processes from reception to storage, crushing, dry boiler combustion, and then flue gas/ash disposal

2005

Demonstration test Component technology development results-based deployment toward demonstration tests

1.Woody biomass technology investigation 2.Pre-treatment technology development

Planning

3.Combustion test and evaluation

Installation works

4.FS for commercialization

Demonstration test

[Review of forest biomass utilization by local governments] Utilization planning and system design/verification

Supply system and other improvement/development

References

1) Kazuhiro Mae: Coal Utilization Technology Information Journal No. 253 pp. 3~5 (Feb., 2002) 2) Hiroshi Yuasa: A collection of lectures from Oct. 2003 Thermal/Nuclear Power Generation Convention in Fukuoka, pp102/103

60

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (De-ashing and Reforming Technologies)

3D1. Hyper-Coal based High Efficiency Combustion Technology(Hyper Coal) In charge of research and development: Center for Coal Utilization, Japan; National Institute of Advanced Industrial Science and Technology; and Kobe Steel, Ltd. Project type: Development and Survey of Next Generation Technology for Coal Utilization, promoted by New Energy and Industrial Technology Development Organization (NEDO) Period: 2002-2007 (6 years)

Outline of the technology

1.Background and object Coal is expected to increase the demand owing to the abundant

steam turbine) realizes higher efficient power generation than

reserves, the expectation of stable supply, and the low price,

that of existing pulverized coal fired power generation. To this

though the influence of CO2 and other substances on the

point, if coal can remove impurities such as ash and alkali

environment is relatively large compared with other fossil fuels.

metals, the resulting clean coal can be used as fuel to directly

In the situation, to decrease the emissions of CO2 from coal fired

combust in gas turbine.

power plants which account for large percentage in the coal

Regarding the issue, NEDO conducts development of technology

utilization field, it is important to develop a power generation

of combined power generation system, where the coal is treated

technology of higher thermal efficiency than ever, and to bring the

by solvent extraction and ion exchange to remove ash and alkali

technology widespread use over the world.

metals to obtain clean coal (Hyper-Coal), which is then directly

If coal is utilized as a gas turbine fuel, the adoption of combined

combusted in gas turbines.

cycle power generation system (combination of gas turbine and 2.What is Hyper-Coal? A solvent having strong affinity with coal is applied to the coal extraction, and then unnecessary ash is sedimented to remove from the coal to obtain very low ash coal (Hyper-Coal). Charcoal

Hyper-Coal

Solvent

Coal

Solvent penetrates into coal

Cohesion of coal becomes weak, and soluble portions of coal dissolve.

Insoluble portions and ash are sedimented to remove.

Extract residue charcoal

Fig. 1 Conceptual drawing of Hyper coal manufacturing from coal

3.Hyper-Coal production facilities (1)Preheating-extraction unit

(2)Sedimentation-separation unit

Coal is extracted by a solvent, and then is

The unit is a sedimentation tank having coal

treated by rapid filtration to remove residue, thus

extraction performance, (design temperature:

Hyper-Coal is produced. (Design temperature:

500 C, design pressure: 5 MPa).

500 C, design pressure: 3MPa)

arranged

The unit produces various grades of Hyper-Coal

determine the sedimenting condition of non-

samples.

dissolved ingredients under pressurized and

O

O

five

valves

collect

Vertically

samples

to

heated conditions.

Photo 1 Preheating-extraction unit

61

Photo 2 Sedimentation separation unit

Clean Coal Technologies in Japan

4.Features of Hyper-Coal - Ash content is decreased to 200 ppm or lower level. Alkali

excellent gasification raw material, and it is expected to increase

metals (Na, K) are decreased to 0.5 ppm or lower level by ion

high efficiency of gasification.

exchange. - Calorific value increases by about 10-20% from that of original coal. - Inorganic sulfur is completely removed. - Content of solid state trace amount of heavy metals is significantly decreased, (to 1/100 or smaller). - The residue generated by 30-40% to the original coal during the production stage can be used as general coal. - The production cost is low, about 950-1,200 yen/ton-HPC. - The HPC has excellent ignitability and burn-off property. - The HPC shows high flowability, and is a good carbon material for direct reduction iron and for smelting nonferrous metals. - Since HPC is rich in volatile matter and is free from ash, it is Photo 3 Test apparatus for manufacturing Hyper coal continuously

5.Configuration of Hyper-Coal based high efficiency power generation system Overseas mining site (coal mine) Roughly deashed coal (ash content: 5% or less)

Ion exchange vessels remove alkali metals which cause high temperature corrosion.

Coal is charged into the solvent, and the system is pressurized and heated to let the coal portions disperse into the solvent. Insoluble ash is treated by the settler to sediment by gravity to remove as the residue coal. The solvent containing dispersed coal portions is sent to the ion exchange vessels.

The material is flash-sprayed into the drying tower to separate the solvent. The solvent is recovered to reuse.

The gas turbine combined cycle power generation system is a power generation system which combines gas turbine with steam turbine. When a gas turbine of 1350oC level of combustion gas temperature is used, about 20% of CO2 emission reduction is attained compared with the pulverized coal fired power generation system.

Conventional power generation system. Power is generated by combusting the residue coal.

6.Concept of Hyper-Coal based power generation system

7.Schedule of research and development

Post-evaluation

Interim evaluation

62

Part2 Outline of CCT Multi-Purpose Coal Utilization Technologies (Deashing and Reforming Technologies)

3D2. Low-Rank Coal Upgrading Technology (UBC Process) In charge of research and development: Japan Coal Energy Center; the Institute of Applied Energy; Kobe Steel, Ltd.; Nissho Iwai Corp. Project type:1. Low-rank coal upgrading technology-related investigation 2. Joint research of technologies applicable to coal producing countries Period: 1. 1995-1998(4 years) 2. 1999-2004(6 years)

Outline of technology

1.Background and process outline Brown and sub-bituminous coal resources accounting for about

also greatly to environmental problems.

50% of coal reserves are called low-rank coal whose applications

upgrading technology (UBC Process) is under development as a

are limited due to its low heating value and spontaneous

technology to make effective use of such low-rank coal.

combustion property. Many of these low-rank coals, however,

This process, an adaptation of slurry dewatering technology of

are featured such as by low sulfur/ash contents, unlike

the brown coal liquefaction process, consists of 3 stages; 1)

bituminous coal. So if they could be efficiently upgraded and

slurry preparation/dewatering, 2) solid-liquid separation/solvent

converted into high-grade high-heating value coal, it will then

recovery, and 3) briquetting.

The low-rank coal

contribute not only to the security of stable energy supply but

Raw coal

Asphalt

Slurry dewatering

Solid-liquid separation Decanter

Evaporator (140 C/350kPa) O

Slurry preparation Solvent recovery

Waste water

Recycle solvent

Upgraded brown coal (UBC) Upgraded brown coal briquette

Fig.1 Low-Rank Coal Upgrading Process (UBC Process) Scheme

At the stage of slurry preparation/dewatering, after pulvelized

moisture and accumulation of heat of wetting. The right figure

high moisture low-rank coal is mixed with recycled oil (normally

shows this phenomenon conceptually.

petroleum light oil), then laced with heavy oil (such as asphalt), and heated in a shell & tube-type evaporator, moisture is

Befor dewatering

After dewatering

recovered as water vapor. This water vapor is sent to the shell side of the evaporator after pressurized by a compressor to use the waste-heat as a heating source, thereby having so far substantially saving energy consumption at the stage of dewatering. Low-rank coal also contains numerous pores and the moisture within them is removed in the course of evaporation.

Capillary water

During that time, laced heavy oil is effectively

Surface water

adsorbed onto pore surfaces, thus preventing spontaneous combustion. Moreover, the heavy oil expresses its nature to

Selective adsorption of asphalt onto pore surfaces

Asphalt

Fig.2 Fundamentals of Low-Rank Coal Upgrading

water repellency, functioning to prevent the re-adsorption of

63

Clean Coal Technologies in Japan

At the stage of solid-liquid separation/solvent recovery, after recycled solvent is recovered from the dewatered slurry by the decanter, the recycled solvent remaining in the pores of upgraded coal is also recovered by the steam tubular drier. Upgraded coal obtained from UBC Process is still in a powdery state, requiring to be briquetted due to the necessity of transportation except when consumers are located nearby. The upgraded coal, normally binder-less briquettable, can be easily briquetted, using a double roll briquetter. The right figure shows a photo of briquetted upgraded-coal. Photo 1 Briquetted UBC

2.Development target 1)Upgrading cost

4.Future assignments and prospective commercialization

If bituminous coal with a heating value of 6,500kcal/kg is

A demonstration-plant of 5 tons/day (raw coal-base) built in

assumed 20 dollars/ton in FOB price, the FOB price of 4,500-

Cirebon of the Java Barat province, Indonesia, is now in

kcal/kg sub-bituminous coal is supposed some 13 dollars/ton in

operation, where the Ministry of Energy and Mineral Resources’

calorific equivalent. If it is assumed that, from this, upgraded coal

Research and Development Agency, Indonesia and the Japan

of 6,500kcal/kg should be obtained, the guideline for treatment

Coal Energy Center are main promoters.

cost will be set around 7 dollars/ton. Even with advantages of

In Asia-Oceania region, there are a lot of low-rank coal

low-rank coal such as its low ash contents and other features

resources. The coal mining companies, which have low-rank

borne in mind, it is necessary to target about 7 to 9 dollars/ton for

coal, are highly interested in UBC process, hoping its earlier

treatment costs.

commercialization.

2)Thermal efficiency for upgrading Thermal efficiency in the upgrading process needs to be 90% or more so that higher thermal efficiency than at direct low-rank coal firing power plants may be achieved in terms of overall comparison from UBC firing power generation.

3.Development in progress and results The heating value of upgraded coal, though it is varied depending upon coal properties has been improved to around 6,500kcal/kg, with its spontaneous combustion problem also successfully suppressed.

It has also been confirmed that briquetted

upgraded-coal is similar to normal bituminous coal in easiness of

Photo 2 Low-Rank Coal Upgrading Demonstration Plant

handling and re-crushing. Furthermore, upgraded coal, if burnt, quite easily burns itself out to leave almost no un-burnt portion even under low-NOx combustion conditions, assuring that it also has excellent characteristics as fuel.

Reference

1) Toru Sugita et al: UBC(Upgraded Brown Coal) Process Development, Kobe Steel Engineering Reports, 53, 42 (2003)

64

Part2 Outline of CCT Environmental Protection Technologies (Coal Ash Effective Use Technologies)

4A1. Coal Ash Generation Process and Application Fields Outline of technology

1.Background and general status of generation process Coal ash has, since it was commercialized as cement admixture

Coal burning methods are roughly divided as follows:

in the first half of the 1950’s, been widely used in applications

(1) Pulverized coal burning (dry-type)

such as for cement raw material, cement mixture, roadbed

(2) Stoker firing

material, backfilling material, and piling-up material, finding its

(3) Fluidized-bed burning

way mostly in the cement sector, particularly, as cement raw

(4) Circulating fluidized-bed burning

material (clay-alternative). 2.Generation rate Power transmission

According to a questionnaire survey conducted by the Center for Coal Utilization, Japan in 2001, the coal ash generation rate in

Steam

Japan is 8,810 thousand tons a year, up 5% in ratio or 380

Household/factory

thousand tons in quantity from the preceding year. Most coal-

Steam turbine

Generator

firing boilers for the electric utility industry are those burning

Transformer

pulverized coal. On the other hand, in general industries, 132 Boiler

coal-firing boilers are in operation with an installed power

Chimney stack

Coal-fired power plant

generation capacity of 1,000kW or more and, by burning Economizer

methods, the majority is accounted for by pulverized coal burning

Air pre-heater

(72 boilers). In terms of boiler capacity (steam generation rate),

Electrostatic precipitator

boilers of 50t/h or less are mostly of a stoker burning type while Clinker hopper

many of 100t/h or more burn pulverized coal. Fig. 2 shows changes in the rate of coal ash utilization as well as generation from electric power utilities and 1,000kW or more-

Fly ash (85~95%)

Breaker

installed power generation capacity establishments in general industries from 1993 through 2001. Bottom ash (5~15%)

Rate of Utilization

Grader

Coal ash (thousand tons)

Rate of generation

Silo

De-watering tank

Silo

Bagger

Dump truck

Ship

Truck

Silo

Humidifier

Jet vac truck Dump truck

Humidifier

Jet vac truck Dump truck

Fig. 1. Process Example of Coal Ash Generation from a Pulverized Coal-Firing Boiler Source: Data from the Japan Fly Ash Association

Year

Fig. 2. Changes in Coal Ash Generation and Utilization Rates

3.Physicality of coal ash In Japan, 90% or more of coal ash generated from pulverized

between finer clay and coarser fine-grained sand for the use as

coal burning, dwarfing 7% or so from fluidized-bed and some 1-

ground material.

2% from stoker burning.

The chemical composition abounds in silica (SiO2) and alumina (Al2O3),

The generation ratio of fly ash and

clinker ash (bottom ash) is 90:10.

resembling mountain soil, and these two inorganic components alone

As for the shape of coal ash particle, low-melting point ash is

account for 70-80% of total. Other than these, ferric oxide (Fe2O3),

often globular while much of high-melting point ash is

magnesium oxide (MgO), and calcium oxide (CaO) are also contained in

indeterminate in shape. The average grain size of fly ash from

slight amounts. In Japan, the physicality of coal wide varies since coal

pulverized coal burning is about 25 m, similar to silt in fineness

of 100 brands or more is imported from all over the world.

65

Clean Coal Technologies in Japan

4.Application fields Table 1 shows by-sector rates of effective utilization in 2001.

increase can hardly be expected. In coping with a likely increase

The utilization in the cement sector increases year after year,

in coal ash in the future, therefore, an important task should be to

reaching 5,343 thousand tons or 74.5% of the 7,173 thousand

expand its utilization in other sectors, expecting its application as

tons used in all sectors combined. Recently, however, cement

civil engineering material in particular due to its high potential to

production has been on a decrease and its future substantial

be used in large quantities.

Table 1 Breakdown of Fields for Effective Coal Ash Utilization (2001) Electric utilities

Item Sector

Description

Rate of utilization

Composition ratio(%)

4,915

68.52

140

2.66

154

8.10

294

4.10

87

1.65

47

2.47

134

1.87

3,835

72.76

1,508

79.28

5,343

74.49

271

5.14

94

4.94

365

5.09

Civil work-purpose

67

1.27

22

1.16

89

1.24

Power supply construction-purpose

20

0.38

0

0.00

20

0.28

Roadbed material

47

0.89

54

2.84

101

1.41

3

0.06

0

0.00

3

0.04

Coal mine filling material

320

6.07

0

0.00

320

4.46

Sub-total

728

13.81

170

8.94

898

12.52

Boards as construction material

191

3.62

118

6.20

309

4.31

Artificial light-weight aggregate

24

0.46

0

0.00

24

0.33

Secondary concrete product

35

0.66

3

0.16

38

0.53

250

4.74

121

6.36

371

5.17

Fertilizer (including snow melting agent)

42

0.80

12

0.63

54

0.75

Soil conditioner

10

0.19

80

4.21

90

1.25

Sub-total

52

0.99

92

4.84

144

2.01

Sewage treatment agent

3

0.06

1

0.05

4

0.06

Steel making-purpose

1

0.02

1

0.05

2

0.03

Others

402

7.63

9

0.47

411

5.73

Sub-total

406

7.70

11

0.58

417

5.81

5,271

100.00

1,902

100.00

7,173

100.00

Foundation improving material

Asphalt/filler material

Sub-total

Others

Composition ratio(%) 68.72

Sub-total

Agriculture /forestry/fisheries

Rate of utilization 1,307

Cement admixture

Construction

Composition ratio(%)

Total

68.45

Cement mixture

Civil engineering

Rate of utilization

General industry

3,608

Cement raw material

Cement

[unit : thousand tons]

Total of effective utilization

References

1) The Center for Coal Utilization, Japan: National Coal Ash Fact-Finding Survey Report (2001 results), (2003) 2) Environmental Technology Association/the Japan Fly Ash Association Coal Ash Handbook 2000 Edition, (2000) 3) Nobumichi Hosoda: CCUJ, Coal Ash Utilization Symposium lecture collection, (1998) 4) Natural Resources and Fuel Department, the Agency for Natural Resources and Energy: Coal Note (2003 edition), (2003)

66

Part2 Outline of CCT Environmental Protection Technologies (Coal Ash Effective Use Technologies)

4A2. Effective use for Cement/Concrete Outline of technology

1.Outline of technology Utilization of fly ash in the cement sector has long been

1950’s, standards were established for fly ash in 1958 and then

challenged through investigations into pozzolana.

for fly ash cement in 1960, encouraging wide applications for

Enhanced

research on the use of fly ash as a good-quality alternative to

general concrete structures.

pozzolana brought its first late-1940’s application to concrete

In the meantime, fly ash came to be used as a clay-alternative in

admixture of structures like a dam in the United States for

cement raw material in 1978 and, as of 2001, 68.5% of the total

subsequent further dissemination into other countries. In Japan,

rate of effective utilization is accounted for by such applications.

following its commercialization as cement admixture early in the

2.Utilization in the cement sector 1) Utilization as a clay-alternative in cement raw material

limiting the substitutability of coal ash for clay. At present, about

Cement raw material is composed of lime stone, clay, silica, and

5% of cement raw material is substituted by coal ash but its

silver oxide, with clay accounting for 15% of total composition.

alternative use is said theoretically possible to around 10%.

Coal ash containing silica (SiO2) and alumina (Al2O3) is also used

2) Utilization as cement mixture

as an alternative to such clay. But it contains less SiO2 and more

JIS specifies standards for fly ash cement2), allowing fly ash to

Al2O3 than clay to require more silica as a source of SiO2 which

be mixed by 5-30%. In general, fly ash can also be used as

becomes short if coal ash is used in large quantities, thereby

Portland cement mixture by 5% or less.

3.Utilization in the concrete sector 1) Utilization as concrete admixture

2. Pre-packed concrete

1. Dam concrete

Pre-packed concrete is a concrete product fabricated by casting coarse

In Japan, research on fly ash as concrete admixture started

aggregate of a designated grain size into the mold form or place of

around 1950, demonstrating its favorable performance and

application beforehand and injecting mortar into voids there at an

economy through the first commercialization on a dam site in

appropriate pressure. The mortar used here must be one of high fluidity,

1953.

little material separation, and moderate expansibility and, for this

RCD (roller compacted dam-concrete) is a concrete product

purpose, fly ash is generally mixed by 25-50%.

finished by compacting concrete of ultra-thick consistency with a

Application fields include underwater concrete, mass concrete, and

vibration roller and the then Ministry of Construction-led

repair/reinforcement of existing concrete works. Honshu-Shikoku Bridge

independent technology development tried to rationally embody

substructure works also employed this construction method.

this in a concrete dam, successfully systematizing the trial into

3. High-fluidity concrete

the RCD Construction Method to be commercialized for dam

FEC (fly ash enriched concrete) is a two components-type high-

construction in 1978.

fluidity concrete product using cement and fly ash as powder

Dam concrete is generally required not to become so hot for

material. It contains as much as 40% or more of fly ash, giving

prevented cracks. Due to this severe requirement for RCD, only

such features as the excellent self-filling capability to need no

part of cement is replaced by fly ash for the purpose of limiting an

compaction after cast, scarce cracks due to heat of hydration,

increase in temperature. The replacement ratio used is mostly

increasing long-term strength, and higher durability against alkali

20-30%. As many as some 30 dams have so far been built by

aggregate reaction and salt/acid damages.

this construction method, justifying its evaluation as a well-

FS (fly ash and slag concrete) using steel slag and coal ash as

established engineering method in terms of technology.

aggregate is a plain concrete product developed for wave-

67

Clean Coal Technologies in Japan

breaker superstructure works and foot protection/anti-turbulence

or qualities likely to prove effective as admixture despite their

blocks which are not required to be so strong.

sub-standard state were added to JIS Standards3) as 4th-grade

4. Industrial standards for concrete-purpose fly ash

items, thereby facilitating the selection of a quality suitable for the

Following the evaluation of fly ash as concrete admixture of

purpose of utilization. Class-1 fine fly ash is used as admixture

excellent performance due to its high fineness and few unburnt

such as for concrete products that must cut off water, be durable,

carbon contents, high-fineness items were commercialized by

etc. including ocean concrete and long haul- and pressure-

means of an advanced grader and higher-performance qualities

transported special back-filling material.

Table 1 Quality of Fly Ash (JIS-A 6201)

Class Item

Class I fly ash

3.0 or less

Density (g/cm3)

5.0 or less

8.0 or less

5.0 or less

1.95 or more 10 or less

40 or less

40 or less

70 or less

5000 or more

2500 or more

2500 or more

1500 or more

105 or more

95 or more

85 or more

75 or more

Material age: 28 days

90 or more

80 or more

80 or more

60 or more

Material age: 91 days

100 or more

90 or more

90 or more

70 or more

Residue on 45 m sieve (screen sieve method) *3(%) Specific surface area (Blaine method) (cm2/g) Flow value ratio (%)

Activity index (%)

Class IV fly ash

1.0 or less

Moisture content (%)

Fineness*2

Class III fly ash

45.0 or more

Silica dioxide (%)

Ignition loss *1(%)

Class II fly ash

*1 In place of ignition loss, the unburnt carbon content ratio may be measured by the method specified in JIS M 8819 or JIS R 1603 to apply to the result a stipulated value of ignition loss. *2 Base fineness on a screen sieve method or Blaine method. *3 In case of a screen sieve method-based fineness, put down with the result of specific surface area tests by a Blaine method.

Application to dam

Application to building

References

1) The Japan Cement Association: Common Practice of Cement, (2000) 2) JIS R 5213-1997, (1997) 3) JIS A 6201-1999, (1999)

68

Part2 Outline of CCT Environmental Protection Technologies (Coal Ash Effective Use Technologies)

4A3.Effective use for Civil Engineering/Construction and Others Outline of technology

1.Outline of technology Coal ash is widely used, other than for concrete, in the civil

quantities in the future such as due to further establishment of

engineering sector as road construction, foundation improving,

new coal firing power plants, utilization technologies are now

back-filling, or other earthwork material and in the construction

under active development out of the necessity to expand its

sector as artificial light-weight aggregate. On the other hand, in

utilization in these sectors. Efforts to provide substance to this

the agriculture/forestry/fisheries sector, it is used as a fertilizer or

face some problems including diffusion of technology, exploitation

soil conditioner.

of demand, and improvement of the distribution mechanism.

In coping with well-expected generation of coal ash in large

2.Utilization in the civil engineering 1. Road construction material

2. Earthwork material

The "Outline of Asphalt Pavement" 1) allows fly ash to be used as

Fly ash can be effectively used as piling-up or back-filling

asphalt filler material and clinker ash, as lower subbase material,

material since it is lighter than common earthwork material. In

frost heave depressant, and cutoff layer material.

recent years, therefore, various technology development

Fly ash can be used for the upper/lower subbase and road bed.

efforts6,7,8) have been made, coming up with a number of

A cement stabilization treatment construction method adds fly

applications including a usage in the original powder state with

ash to cement to be treated under moderate moisture contents

cement added as a solidifier to coal ash, utilization as stabilizing

for application.

This construction method realizes early

treatment material, hardening for application, and granulation or

manifestation of strength and achieves long-run stability. Another

other processing to use it. Review is also under way for intended

technology2,3,4,5) has also been developed to process coal ash for

commercialization of fly ash as soft ground improving material or

the use as road construction material.

a construction sludge conditioner due to its high activity of pozzolana as well as property of self-hardening9). Meanwhile, basic research of coal ash’s trace components elution10) goes on since fly ash must be used, not raising any environmental problems, in terms of safety coal-ash utilization as earthwork material.

Photo 1 Application to road

69

Clean Coal Technologies in Japan

3.Utilization in the construction sector

4.Utilization in the agriculture/forestry/fisheries sector

1. Artificial light-weight aggregate

1. FertilizerCoal ash was designated in the capacity of pulverized

Development

efforts11,12)

coal-burning ash as a special fertilizer in 1960 for fly ash and in

have successfully come up with

technology to palletize/calcine coal ash and cement or the like into

1992 for bottom ash.

artificial light-weight aggregate. Demand for it is expected to grow

effective use of hard-to-solve silicic acid contained in coal ash is

A potassium silicate fertilizer making

such as due to the progress of urban development and high rising

also produced about thousands of tons a year.

of buildings, making it important to further technology development

2. Soil conditioner

of artificial light-weight aggregate as well as to reduce its

Clinker ash whose chief ingredients are almost the same as

production cost.

those of ordinary soil, mostly composed of SiO2 and Al2O3, is

2. Others

suitable for the growth of vegetables. Moreover, it is used as sod

The resemblance of its components to the chemical composition of

for golf courses or to improve soil of poor-drainage places or

existing construction materials also allows coal ash to be used as

arable land since its numberless spores hold water well for

clay-alternative raw material for ceramic products such as clay

longer duration of fertilizer effects and, at the same time, its

roofings, bricks, and tiles or a cement mixture for boards

similarity to sand in shape provides comparable water-

(interior/exterior wall material for construction) on the strength of

permeability.

such characteristics.

3.Utilization in the fisheries sector There are long-established cases where coal ash was used for fish breeding reefs and seaweed beds. A recent attempt aims at the use of coal ash as mound material for man-made undersea mountain ranges to cause artificial upwelling currents.13)

Photo 2 Example of Artificial Aggregate Fabricated from Coal Ash (Toughlite)

Photo 3 Application as fertilizer

References

1) The Japan Road Association: Outline of Asphalt Pavement, (1992) 2) Environmental Technology Association/the Japan Fly Ash Association: Coal Ash Handbook 2000 Edition, (2000) 3) Public Works Research Institute: Public Works-Related Material Technology/Technical Review Certification Report "Ash-Roban", (1997) 4) Public Works Research Institute: Public Works-Related Material Technology/Technical Review Certification Report "Pozzotech", (1997) 5) Ohwada et al: 11th Annual Conference on Clean Coal Technology lecture collection, (2001) 6) Shintani et al: CCUJ, Civil Engineering 54th Annual Academic Lecture Meeting, collection of summaries, (1999) 7) Public Works Research Center: Public Works-Related Material Technology/Technical Review Certification Report "Hard Soil-Break Material", (2000) 8) Akira Onaka: The Clean Japan Center’s 11th Resources Recycle Technology Research Presentation Meeting, collection of lecture papers, (2003) 9) Ozasa et al: CCUJ, 11th Annual Conference on Clean Coal Technology lecture collection, (2001) 10) The Japanese Geotechnical Society: Research Committee Report on Utilization of Wastes as Foundations Material, (2000) 11) Ishii et al: The "Bulletin of the Chemical Society of Japan", 5, 431, (1992) 12) Ozasa et al: CCUJ, 10th Annual Conference on Clean Coal Technology lecture collection, (2000) 13) Tatsuo Suzuki: 14th ACAA International Symposium lecture collection, (2001)

70

Part2 Outline of CCT Environmental Protection Technologies (Coal Ash Effective Use Technologies)

4A4. Valuable Resources Recovery Technologies for Coal Ash Outline of technology

1.Outline of technology Coal ash utilization technology is now an R&D subject challenged in

as an absorbent, catalyst, ion-exchanger, and desiccant through

diversified manners from an effective-use-of-resources point of view.

zeolitization, desulfurization agent, antirust, and application such

Review has been made on the recovery of valuable resources

as into admixture and filler of polymeric materials (including

from coal ash by way of physical/chemical treatment, utilization

rubber and plastic).

2.Valuable resources recovery Coal ash contains valuable substances including cenosphere

2) Recovery of valuable resources through chemical treatment

(hollow ash), Magnetite silica, alumina, iron oxide, and titanium

(1)Direct hydrofluoric acid extraction method

oxide, other than which valuable metals are also present though

As a method of recovering valuable resources from fly ash

in trace amounts.

through chemical treatment, the acid extraction method which

1) Recovery of valuable resources through physical treatment

uses an acid mixture of hydrofluoric acid and hydrochloric acid

(1)Magnetite recovery through magnetic separation

has

The recovery of magnetite (Fe3O4) from fly ash is also positioned

characteristically of high purity (99.9% or more) and fine particles

at the pre-process of the chemical treatment method to recover

(1 m or less).

valuable elements such as Si, Al, Ti, and Fe. Magnetite can be

(2)Calcination method

used, e.g., an alternative to heavy separation medium recovered

This method burns fly ash with a source of calcium to change

by magnetic separation.

acid-stable mullite in fly ash into acid-soluble anorthite or

been

developed.

The

SiO2

recovered

here

is

gehlenite, characteristically at a high rate of Al recovery.

3.Artificial zeolite Zeolite is the generic term of hydrated crystalline alumina silicate

coal ash zeolite is obtained if coal ash is boiled with sodium

and, as part of its features, has a porous structure and, therefore,

hydroxide

a large specific surface area as well as contains ion-

separated/washed/de-watered. The zeolite given here is of a Na-

exchangeable cations and crystallization water that can be

P type.

adsorbed/desorbed. On the strength of its such characteristics,

Meanwhile, coal ash zeolite production processes so far

Zeolite is used, e.g., as an adsorbent, catalyst, and disiccant1).

commercialized are batch-wise like those for other than coal ash

It is known that hydrothermal treatment of a coal ash-alkaline

while flow-through continuous synthesis processes have also

aqueous solution mixture2) gives various kinds of zeolite,

been developed4).

depending upon conditions for reaction.

exploitation of applications where large-quantity utilization is well-

The Clean Japan Center3) now conducts demonstration tests at a

expected, reduction of production costs, and technology to

coal ash zeolite production demo-plant of a level of 10 thousand-

synthesize zeolite of a kind suitable for each application.

while

stirring

and

then

solid

contents

are

In addition, review is now made on the

ton/year in 1990. At this coal ash zeolite production process,

Coal ash Caustic soda

Boiling /stirring

Buffer tank

Drainage

Water washing

NaOH drainage pit

De-watering

Water drainage pit Water treatment station

Fig. 1. Coal Ash Zeolite Production Process

71

Primary products storage

Drying

Bagging

Clean Coal Technologies in Japan

4.Utilization in other sectors 1) Desulfurization agent

alternative to plastic admixtures including calcium carbonate,

Dry desulfurization technology using coal ash has been

silica, alumina, wood flour, and pulp.

commercialized because a hardened mixture of coal ash, slack

3) Other

lime, and gypsum has an excellent desulfurization capability.

Other than the above, the present technology development also

2) Admixture/filler for polymeric materials (including rubber and

envisages coal ash characteristics-based applications such as in

plastic)

an agent to prevent rust due to oxidation in steel-making, a water

Fly ash, since it is a gathering of small round glass bead-like fine

cleanup agent, or casting sand.

particles, is under review for its use as a rubber filler or as an

Structure

A

Molecular formula

Pore size (A)

Na 12 [(AlO 2 ) 12 (SiO 2 ) 12 ]

Na type: 4

27H 2 O

Ca type: 5

Pore volume CEC (cc/g) (meq/100g)

Na type: 0.3

548

SiO4

P

X AlO4

Na 6 [(AlO 2 ) 6 (SiO 2 ) 10 ]

Na type: 2.6 Na type: 0.36

15H 2 O

514 *The figure is small but the exchange rate is small.

Na 86 [(AlO 2 ) 86 (SiO 2 ) 106 ]

Na type: 7.4 Na type: 0.24

264H 2 O

473

Cation-containing aluminosilicate found in different kinds for different structures/compositions, with each kind having its own performance and application.

References

1) Environmental Technology Association/the Japan Fly Ash Association: Coal Ash Handbook 2000 Edition, (2000) 2) Akio Itsumi: Japan Soil Science and Plant Nutrition, 58 (3), (1987) 3) The Clean Japan Center: Clean Japan, 86, (1991) 4) Masahiko Matsukata: CCUJ, 12th Annual Conference on Clean Coal Technology lecture collection, (2002)

72

Part2 Outline of CCT Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B1. SOx Reduction Technology Outline of technology

1.Background Sulfur oxides (SOx, mainly SO2) is regulated by way of the K-

their higher performance and lower costs. At present, most of

value control which uses exhaust heights and regional

pulverized coal-fired thermal power plants are equipped with wet

coefficients to limit their emissions as well as the total amount

lime stone and gypsum method-based desulfurization means.

control which defines total emissions from the whole of a

Furthermore, a wet desulfurization method requiring no waste

region.

water treatment is now under development.

In coping with these controls, flue gas desulfurizers

were commercialized in 1973, with later continual efforts for

2.Technology (1)Wet lime stone-gypsum method

stone slurry is reacted on SO2 within exhaust gas for the

Members in charge of research and development: Mitsubishi Heavy Industries, Ltd.; Babcook Hitachi K.K.; Ishikawajima-Harima Heavy Industries Co., Ltd.; CHIYODA Corporation; Kawasaki Heavy Industries, Ltd.; others

recovery of sulfur contents as gypsum (CaSO4-2H2O).

Outline

There are two types of absorption tower as shown in Fig. 1;

The lime stone-gypsum method is found in a soot-separation

CaSO3-0.5H2O oxidation tower-separated types and all-in-one

type which installs in its upstream a dedusting (cooling) tower

internal oxidation types.

for dust collection, HCl/HF removal, and cooling or in a soot-

expensive-to-install/operate internal oxidation types is on a year-

mixed type having no such tower. Soot-separation types are

after-year increase.

used when high-purity gypsum containing no soot/dust is

liquid to contact SO2 in the absorption tower section include

desired. At present, however, more and more soot-mixed types,

Spray Method to spray absorption liquid, Grid Method to shed

less-expensive-to-install, are adopted since a high-performance

absorption liquid on the surface of a grid-like pad, Jet-Bubbling

dust collection system like the advanced low-temperature

Method to blow exhaust gas into absorption liquid, and Water-

electrostatic precipitator has been developed, lowering

Column Method to shed a fountain flow of absorption liquid in the

soot/dust concentrations.

absorption tower.

In the absorption tower, on the other hand, water-mixed lime

For developing countries, a simple type installable in the flue gas

The overall reaction is as follows: CaCO3+SO2+0.5H2O

CaSO3-0.5H2O+CO2

CaSO3-0.5H2O+0.5O2+1.5H2O

CaSO4-2H2O

At present, the utilization of less-

Methods for causing recycled absorption

duct or at the lower part of a smoke stack has also been commercialized.

Item

Oxidation tower-separated type

In-absorption tower oxidation type

Absorption tower

Absorption tower Sulfuric acid

Oxidation tower

Basic flow Gypsum Gas

Gas

Air Lime stone

Lime stone Absorption tank

Gypsum Absorption tower tank

Air

Fig. 1 Outline of Lime Stone-Gypsum Method-Based Desulfurizer

73

Clean Coal Technologies in Japan

(2)Coal ash-based dry desulfurization method

20% and dust collection efficiency of 96% or more. By 2003, it

Members in charge of research and development: Hokkaido Electric Power Co., Inc.; Hitachi, Ltd.; Babcook Hitachi K.K. Kind of project: Subsidized development of oil-alternative energy-related technology for commercialization Development period: 1986-1989

had been installed at No. 1 unit (350 KkW) of Hokkaido Electric Power’s Tomato-Atsuma Thermal Power Plant as a facility

Used desulfurization agent

Boiler Exhaust gas

Water Kneader

Drier

Conveyor

absorption agent and then, using the absorption agent, remove

Blender

Extruder Conveyor

SOx from flue gas. Fig.2 shows an outline of its process. This

Steam Weighing machine

process also includes the stage to manufacture the absorption agent. Desulfurization reaction here is a reaction which allows

Screen

Clean gas Desulfurization fan

Weighing machine

Hot air

from lime stone, calcium hydroxide (Ca(OH)2), and spent

Primary absorption agent

coal ash. This method is to fabricate a new absorption spent

Pre-absorption agent

It is one of technologies developed to make effective use of

Desulfurization silo

Outline

Slack lime

Coal ash

currently in operation to treat half of its flue gas in amount.

Steam generator

Ca(OH)2 to remove SO2. Temperature is conditioned at 100Used desulfurization agent

200 C, where an SOx removal efficiency of 90% or more can be O

Breaker

obtained. The process is also capable of dust collection and

Fig. 2 Coal Ash-Based Dry Desulfurization Method Proces

De-NOx, having achieved a NOx removal efficiency of about (3)Spray Drier Method

giving a particle mixture of gypsum (CaSO4-H2O) and calcium

Members in charge of research and development: Electric Power Development Company; Mitsubishi Heavy Industries, Ltd.; Hokkaido Electric Power Co., Inc. Kind of project: Voluntary under the Green Aid Plan

sulfite (CaSO3-0.5H2O).

down-stream precipitator. Since this method is not enough for

Outline

Electric Power Development Company, as part of the "Green Aid

It is a so-called semi-dry method, where water is added to burnt

Plan," installed a spray drier desulfurizer with an exhaust gas

lime (CaO) to make slack lime (Ca(OH)2) slurry, which is sprayed

treatment capacity of 300Km3N/h (half of total exhaust), which is

into a spray drier, causing SO2 in exhaust gas to react on

currently in operation, at Huangdao Power Plant No. 4 Unit

Ca(OH)2 to be removed.

(210KkW) in Qingdao, China, for 70% desulfurization rate

These particles are recovered at a

good-quality gypsum to be obtained and, moreover, ash remains mixed in, desulfurized particles are disposed of as waste.

Within the drier, desulfurization

reaction and lime stone drying take place at the same time,

verification tests (Oct., 1994 through Oct., 1997).

(4)Furnace desulfurization method

SO2 at a furnace temperature of 760-860 C: O

Members in charge of research and development: Hokkaido Electric Power Co., Inc.; Kyushu Electric Power Co., Inc.; Electric Power Development Company; Chugoku Electric Power Co., Inc.; Mitsubishi Heavy Industries, Ltd.; Ishikawajima-Harima Heavy Industries Co., Ltd.; Kawasaki Heavy Industries, Ltd. Kind of project: Voluntary project

CaCO3

CaO+CO2 CaO+SO2

CaSO3

At present, this method is in practice at normal-pressure fluidized-bed boilers of J-POWER’s Takehara Thermal Power Plant No. 2 Unit as well as pressurized fluidized-bed boilers of Hokkaido Electric Power’s Tomato-Atsuma Thermal Power Plant, Kyushu Electric Power’s New Kanda Thermal Power Plant, and Chugoku Electric Power’s Osaki Thermal Power Plant. At pressurized fluidized-bed boilers, lime stone does not

Outline It is a desulfurization method used for fluidized-bed boilers.

break down into CaO due to the high partial pressure of CO2

Lime stone for desulfurization is mixed with coal to be fed

but SO2 is removed in accordance with the following reaction:

together with coal, causing the following reaction to remove

CaCO3+SO2

CaSO3+CO2

References

1) "Introductory Course: Environmental Preservation Technology /Equipment for Thermal Power Plants IV Desulfurization Equipment", Thermal/Electronic Power Generation Vol. 41 No. 7,911, 1990 2) Kudo et al, "Coal Ash-Based Dry Desulfurizer Development" Thermal/Electronic Power Generation Vol. 41 No. 7,911, 1990 3) "Coal Ash-Based Dry Flue Gas Desulfurizer" pamphlet, Hokkaido Electric Power 4) General View of Thermal Power Generation, Institute of Electric Engineers, 2002

74

Part2 Outline of CCT Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B2. NOx Reduction Technology Outline of tecnology

1.Background Nitrogen oxides are under regulatory control, setting acceptable

commercialized in 1977, with later continual efforts to improve

values of their concentrations by fuel kinds and boiler sizes.

the durability of De-NOx catalysts as well as reduce costs. The

Currently, however, with regulations further intensified, some

De-NOx method used is Selective Catalytic Reduction (SCR)

regions are subject, like sulfur oxides, to the total amount control

Method to decompose nitrogen oxides mainly by using

which provides for overall emissions from each region. In coping

ammonia.

with these regulations, flue gas denitration equipment was

2.Technology (1)Selective contact reduction method process is also so designed that NH3 leaked from the reactor

Members in charge of research and development: Mitsubishi Heavy Industries, Ltd.; Ishikawajima-Harima Heavy Industries Co., Ltd.; Babcook Hitachi K.K.

react on SO3 in exhaust gas, giving NH4HSO4, which is

Outline

separated out in the air pre-heater to clog the piping.

In this method, ammonia (NH3) is blown into exhaust gas,

NOx removal efficiency is around 80-90% for pulverized coal-

allowing ammonia (NH3) to selectively react on nitrogen oxides

fired thermal power plants. On the other hand, measures for

should amount to 5ppm or less and if much NH3 leaks, it will

NOx(NO, NO2), and decomposed them into water (H2O) and

equal dispersion/mixture of NH3 in exhaust gas as well as

Nitrogen (N2). In the De-NOx reactor, since exhaust gas entails

greater uniformity of exhaust gas flows to cope with growing

soot and dust, a grid- or plate-like catalyst is mainly used, as

boiler sizes are contrived such as by placing a current plate

shown in Fig. 1. The catalyst is filled in the reactor, as shown in

called Guide Vane at the gas inlet or dividing the gas inlet into

Photo 1/Photo 2, to react on the NH3 blown into the catalyst layer

grids to be each equipped with an NH3 injection nozzle.

from its inlet, allowing NOx(NO, NO2) to break down into water vapor (H2O) and nitrogen (N2). The catalyst is mainly composed of TiO2, to which vanadium (V), tungsten (W), and the like are

Smokestack

added as active ingredients. 4NO + 4NH3 +O2

4N2 + 6H2O

The temperature range is 350 C, at which the catalyst can O

Catalyst layer

demonstrate its performance. At a lower temperature than this, SO3 in exhaust gas reacts on NH3, giving ammonium hydrogen sulfate (NH4HSO4) to cover the catalyst surface, thereby reducing the De-NOx performance. At a temperature higher than 350 C, the NH4HSO4 decomposes, offering high De-NOx O

performance, regardless of SO3 concentrations.

Exhaust gas

At a high

Reactor

temperature above 400 C, NH3 is oxidized to decrease in O

amount, thereby reducing the De-NOx performance.

Fig. 1 Selective Contact Reduction Method Denitration Process

The

Photo 1 Grid-like catalyst

Photo 2 Plate-like catalyst

75

Clean Coal Technologies in Japan

(2)Selective Non-Catalytic Reduction (SNCR) Method

Members in charge of research and development: Chubu Electric Power Co., Inc.; Mitsubishi Heavy Industries, Ltd. Kind of project: Voluntary project Outline It is a method to, as shown in Fig.2, blow NH3 into the boiler section where exhaust gas temperature is 850-950 C and break O

Injection nozzle

down NOx into H2 and H2O without any catalyst. Despite its Brine water for nozzle-cooling

merits of requiring no catalyst and lower installation costs, this method achieving NOx removal efficiency of as low as some 40% at the NH3/NOx molar ratio of 1.5 is used in regions/equipment where there is no need for high NOx removal efficiency. More NH3 is also leaked than by the selective contact reduction method, claiming measures to cope with NH4HSO4

AH

Ammonia

precipitation in the case of high-SO3 concentration exhaust gas.

SAH

Mixer

This technology is mainly used such as at small commercial

Air for dilution

boilers and refuse incinerators. With respects to thermal power

FDF

Booster fan

plant applications, it was installed only at Chubu Electric Power’s Chita Thermal Power Plant No. 2 Unit (375kw) in 1977.

Fig. 2 Selective Non-Catalytic Denitration Method’s NOx Removal Process

(3)Radical injection method

Members in charge of research and development: Center for Coal Utilization, Japan Kind of project: Subsidized coal production/utilization technology promotion Development period: 1999-2002 Outline This method, as shown in Fig.3, injects argon plasma into NH3, generating NH2-, NH2-, and other plasmas, which are then blown into the boiler to decompose NOx into H2 and H2O.

It is a

technology aimed at NOx concentration of 10ppm or less for its target performance. At present, basic research is under way at the Center for Coal Utilization, Japan, toward expected commercialization around 2010.

Fig.3 Outline of Radical Injection Method

References

1) Masahiro Ozawa et al, "Latest Flue Gas Denitrator Technology", Ishikawajima-Harima Technical Journal, Vol. 39 , No. 6, 1999 2) Tadamasa Sengoku et al, "Selective Non-Catalytic Denitration Method for Boilers", Thermal/Nuclear Power Generation, Vol. 29, No. 5, 1978 3) Coal Utilization Next-Generation Technology Development Survey; Environment-friendly coal combustion technology field (advanced flue gas treatment technology)/NEDO results report, March 2002 4) Masayuki Hirano, "New Flue Gas Denitrator Technologies for Large Boilers/Gas Turbines", Thermal/Electronic Power Generation, Vol. 50, No. 8, 1999

76

Part2 Outline of CCT Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B3. De-SOx and De-NOx Technology Outline of technology

1.Background A wet desulfurization method is also matured in terms of

but also measures against leaked ammonia.

Development

technology but requires a variety of feed water as well as

efforts are, therefore, under way for a dry combined

advanced waste water treatment measures.

Meanwhile, an

desulfurization De-NOx method to remove NOx and SOx at the

already commercialized ammonia selective reduction (SCR)

same time without any feed/waste water treatment or De-NOx

method needs not only life control of expensive De-NOx catalysts

catalyst.

2.Technology (1)Active carbon adsorption method

Members in charge of research and development: Electric Power Development Company; Sumitomo Heavy Industries, Ltd.; Mitsui Mining Co., Ltd. Kind of project: Voluntary support project for coal utilization promotion Outline The active carbon absorption method is to cause a reaction

first stage, with De-NOx performance also achieving 80% NOx

between SO2 in exhaust gas and blown-in NH3 on active carbon

removal efficiency. This technology, verified after upscaled to a

at 120-150 C, thereby converting SO2 into such form as

capacity to treat gas of a 150Km3N/h level in amount, was

O

ammonium hydrogen sulfate (NH4HSO4) and ammonium sulfate

adopted in 1995 for the De-NOx unit of Takehara Coal Thermal

((NH4)2SO4) for adsorption/removal while decomposing NOx into

Power Plant No. 2 Unit’s normal-pressure fluidized-bed boiler

nitrogen and water as SCR Method does.

Fig.1 shows the

(350KkW) and is currently in operation. It was further installed in

The moving-bed adsorption tower (desulfurization

2002 at J-Power’s Isogo Thermal Power Plant No. 1 New Unit

tower) at the first-stage removes SO2 and, at the second stage

(600KkW) as its desulfurizer (Photo 1) currently in operation but

(denitration tower), NOx is decomposed.

none is operated as combined desulfurization-denitration

process.

This method first

equipment.

removes SOx and then NOx since, as shown in the figure, the presence of high-concentration SO2 tends to lower NOx removal efficiency.

Active carbon

Active carbon that has absorbed NH4HSO4 is heated to 350 C or O

not blown in but since, at the time of this desorption, the following reaction with carbon contents occurs, consuming active carbon,

Hot air

Desorption tower

Exhaust gas

Denitration tower

regenerated. In the desulfurization tower, SO2 can be adsorbed and removed in the form of sulfuric acid (H2SO4) even if NH3 is

Desulfurization tower

above in the desorption tower to desorb NH4HSO4 after decomposing it into NH3 and SO2 while active carbon is

NH3 is added at the time of desulfurization for the purpose of preventing this. H2SO4

Fig.1 Active Carbon-Method Desulfurization Process

SO3+H2O

SO3+0.5C

SO2+CO2

Desorbed SO2 is reduced into elemental sulfur by coal at 900 C O

to be recovered. There is another method which oxidizes SO2 into SO3 to recover it as sulfuric acid. During the development of this technology carried on at JPower’s Matsushima Thermal Power Plant, first, an active carbon desulfurization method (with an adsorption tower unit) that can treat gas of a 300Km3N/h (90KkW-equivalent) level in amount was subjected to verification tests (1983-1986), obtaining 98% SOx and some 30% NOx removal efficiency. improvement

in

De-NOx

performance,

For further a

combined

desulfurization De-NOx pilot plant that can treat 3,000m3N/h of gas with two tower units was tested (1984-1986).

SOx was Photo 1 Active Carbon-Method Desulfurizer

almost completely removed by the desulfurization tower at the

77

Hot air

Desorbed gas

Clean Coal Technologies in Japan

(2)Electron beam method

Members in charge of research and development: Ebara Corporation; Chubu Electric Power Co., Inc.; the Japan Atomic Energy Research Institute; others Kind of project: Voluntary project Outline

For this method, technology development was undertaken by

This method, as shown in Fig.2, injects an electron beam on

Ebara Corporation and U.S. partners including DOE through their

SOx/NOx in exhaust gas and blown-in NH3 to cause a reaction

joint contributions (1981-1987). In Japan, based on development

for their recovery as ammonium sulfate ((NH4)2SO4) or

results, a pilot plant (that can treat gas of 12,000m3N/h) was built

ammonium nitrate (NH4NO3) in the downstream precipitator. By-

at Chubu Electric Power’s Shin-Nagoya Power Plant, where the

products; ammonium sulfate and ammonium nitrate are used as

technology has been verified (1991-1994).

fertilizers. The performance of 98% or more SOx and 80% NOx

Regarding this technology, a plant that can treat gas of

removal efficiencies for the NH3/NO molar ratio of 1 is obtained at

300Km3N/h (90KkW) (Photo 2) was installed at Chengdu Heat-

70-120 C.

NOx removal efficiency also characteristically

Electricity Factory (co-generation power plant) in Sichuan

increases with increasing SO2 concentration, though SOx

province, China, and currently in operation for demonstration

removal efficiency does not affect the inlet concentration of SO2.

under 80% NOx removal efficiency conditions.

O

Existing boiler

Air pre- Dry electrostatic heater precipitator

Smokestack

Air

Cooling water

Electron beam generator Dry electrostatic precipitator

Reactor Cooling tower

Granulator

Ammonia equipment

Nitrogen fertilizer (ammonium sulfate/ammonium nitrate)

Fig.2 Electron Beam-Method Desulfurization Process

Photo 2 Electron Beam Method Desulferizer

References

1) Hanada et al, "Dry Desulfurization-Denitration-Technology Dry Active Carbon-Method Sulfur Recovery Formula at Coal Thermal Power Plant" Thermal/Electronic Power Generation, Vol. 40, No. 3, 1989 2) "Renewing Isogo Thermal Power Plant" pamphlet, Electric Power Development Company 3) Aoki, "Electronic Beam Flue Gas Treatment Technology", Fuel Association Journal, Vol. 69, No. 3, 1990 4) S. Hirono et al, "Ebara Electro-Beam Simultaneous SOx/NOx Removal", proc 25th Int Tech Conf Util Sys 2000

78

Part2 Outline of CCT Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B4. Soot/dust Treatment Technology and Trace Elements Removal Technology Outline of technology

1.Background Soot and dust are regulated, like NOx, under the provisions for

bed

by-fuel kind/-boiler size concentrations.

At present, however,

technologies is also under way for high-efficiency power

there are some regions subject to the total amount control which

generation, using cyclones and ceramics/metal precision-removal

limits the overall emissions from each region as in the case of

filters.

sulfur and nitrogen oxides. In coping with such regulations, an

On the other hand, trace materials-related control is now being

electrostatic precipitator was employed in Yokosuka Thermal

intensified such as through the addition of boron (B) and

Power Plant for the first time in the world in 1966 for mainly other

selenium (Se) to waste water materials to be regulated and U.S.

thermal power plants to follow suit. Development of pressurized-

regulations on mercury (Hg).

combustion

and

coal

gasification

combined-cycle

2.Technology (1)Electrostatic precipitation method

Members in charge of research and development: Mitsubishi Heavy Industries, Ltd.; Hitachi, Ltd.; Sumitomo Heavy Industries, Ltd.; others Outline DC high voltage

The electrostatic precipitation method is a method to remove soot/dust in exhaust gas in accordance with the theory that any

Power supply

dust negatively charged by corona discharge at the discharge electrode adheres to the positive dust-collecting electrode. The soot/dust that adhered to the electrode is allowed to come off and Discharge electrode

drop by giving a shock to the electrode with a hammering device. The dust collection performance depends upon the electrical

Collected soot/dust

resistance of soot/dust, preferring particles of 104-1011 -cm in the apparent electrical resistivity range. In the case of pulverized

Dust collecting electrode

coal thermal, electrical resistance of many particles is high, urging various measures to be taken against high-electrical resistance particles. As one of such measures, temperature conditions for dust

Flue gas (from boiler)

collection are adjusted. Electrical resistance changes as shown in Fig.2. Those successfully developed/commercialized from the

Fig. 1 Theory of Electrostatic Precipitator

use of such characteristics are a high-temperature electrostatic precipitator run at 350 C, a higher temperature than that of O

Low-alkali /high-sulfur coal

150 C) to lower electrical resistance and an advanced lowO

temperature electrostatic precipitator run, with its electrical

Low-alkali /low-sulfur coal

resistance lowered by operating it at a dew point-or-lower Other than these, successful

commercialization is found in the moving electrode method which brushes off soot/dust by moving the electrode to prevent back corona due to dust accumulation at the electrode and a semi-wet electrostatic precipitator where a film of liquid is shed to wash away dust. Another measure has also been taken with electric discharge methods commercialized, including an intermittent charge method to supply a pulsed voltage on the order of several milliseconds and a pulse charge method for tens of microseconds-order energization. At present, leading pulverized coal-firing plants built in and after

Advanced Low-temperature ESP Conventional low-temperature ESP

O

Electrical resistivity ( -cm)

temperature (90-100 C).

High-temperature ESP

conventional low-temperature electrostatic precipitators (130-

High-alkali /high-sulfur coal High-alkali /low-sulfur coal

1990 are provided with very low-temperature electrostatic dustcollection means that can treat different properties as well as

Temperature(OC)

shapes of soot/dust.

Fig. 2 Temperature Effects on Electrical Resistance of Coal Ash 79

Clean Coal Technologies in Japan

(2)High-temperature dust collection method

Members in charge of research and development: Mitsubishi Heavy Industries, Ltd.; Hitachi, Ltd.; Kawasaki Heavy Industries Co., Ltd.; others Outline This is under development as a technology to remove soot/dust

Plant but also under the EAGLE Project. It is also expected to

from hot gas for pressurized-bed combustion and integrated

be used at an IGCC demonstration unit (250KkW) slated for

gasification combined-cycle (IGCC) power generation processes.

initial operation in 2007.

This technology utilizes a multi-cyclone, ceramics- or metalbased filter and the granular-bed method using silica or mullite material where soot/dust is removed. Multi-cyclones are mainly used for rough removal.

Those used for precision removal

include ceramic or metal filters of a cylindrical porous body into which SiC and other inorganic materials and iron-aluminum alloys are formed (Photo 1).

Such filters used here were

developed by Nihon Garasu Kogyo or overseas by Paul Schumacher.

Such technologies, now under durability

evaluation/demonstration,

are

used

for

pressurized-bed

combustion power generation at Hokkaido Electric Power’s Tomato-Atsuma Thermal Power Plant, with their verification tests conducted not only for IGCC at 200-ton/day Nakoso IGCC Pilot

Photo 1 SiC Ceramic Filter

(3)Mercury removal method

Members in charge of research and development: Center for Coal Utilization, Japan Kind of project: Subsidized coal production/utilization technology promotion project Outline Among trace contents of coal, mercury is cited as a material

inorganic minerals, and lime stone as materials which absorb

released into the atmosphere at the highest rate, with about 30

mercury and is now evaluating their absorption characteristics.

percent of the failure to be removed at precipitators/desulfurizers

The research results prove that, if the method to inject active

proved to be released.

However, bivalent mercury (Hg2+) is

carbon or an FCC ash catalyst into the flue for the removal of

nearly all removed, leaving nonvalent one (Hg) as discharge

metal mercury is combined with removal at the flue gas

matter. A method to remove this nonvalent mercury is under

desulfurizer, 90% or more mercury can be removed easily.

active review. The Center for Coal Utilization, Japan, though still in the process of basic research, selected active carbon, natural

References

1) "Thermal/Nuclear Power Generation Companion, 6th edition", Thermal/Nuclear Power Generation Association, 2002 2) Sato, "Design and Actual Operations of High-Temperature Electrostatic Precipitators", Thermal/Nuclear, Vol. 34, No. 4, 1983 3) Tsuchiya et al, "Technology Development of Low Low-Temperature EP in Coal Thermal-Purpose High-Performance Flue Gas Treatment System", MHI Technical Journal Vol. 34, No. 3, 1997 4) "Toward the Realization of Integrated Gasification Combined-Cycle Power Generation", CRIEPI Review, No. 44, 2001 5) Coal-Based Next-Generation Technology Development Survey /Environment-Friendly Coal Combustion Technology Field (Trace Element Measurement/Removal Technology), NEDO results report, 2003

80

Part2 Outline of CCT Clean Coal Technologies in Japan

Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B5. Gas Cleaning Technology

To dust collector

Coal gas (from dust collector)

Cyclone Desulfurization agent

1.Background For solution of problems with such a wet gas purification method,

generation and fuel synthesis technologies, it is necessary to

efforts are now exercised to develop dry gas purification

Air

SOx reduction tower

Reproduction tower

Sulfur condenser

Desulfurization tower

For the development of coal gasification gas-based power

Heat exchanger

Anthracite

Outline of technology

Desulfurization process Reduction process

Ceramic filter

technology is found in the wet gas purification method which, after

COS conversion catalyst

Scrubber (dehalogenation, deammonification)

Carrier

Ash

Gas in excess

Fig.4 Fixed-Bed Desulfurization Process

Sulfur

Coal gas

Separator

scrubber, desulfurizes the gas with a methyldiethylamine (MDEA)

Soot/dust filter

Fig.3 Fluidized-Bed Desulfurization Process

or other amine-based liquid absorbent for gas purification. This

Distributor

method, however, requires the gas to be cooled down to around room temperature, thus losing much heat.

Reduction process

To gas turbine

Coal gasifier

removing water-soluble halides and other contents by a water

Sulfur recovery equipment

Sulfur

Air

remove sulfur compounds (H2S, COS), halides (HCl, HF), and other gas contents. As shown in Fig.1 a main application of this

Gas for sulfur reduction

Dust filter

Sulfur recovery equipment

Furthermore, the

Nakoso Pilot Plant Project.

This fact indicates that IGCC-

Soot/dust

dedicated technologies have already reached their validation

To sulfur recovery system

stage.

process becomes complex since it requires not only a heat H 2S absorption tower

exchanger but also a catalyst which changes hard-to-remove COS into H2S. It is also difficult to precisely reduce sulfur compounds to a 1-ppm level.

Renewal tower Reboiler

Fig. 1 Wet Gas Purification Process

Air

At present, a desulfurization agent that can reduce sulfur compounds to a 1ppm level is under development for use in such

Reduction gas (coal gas)

applications as molten carbonate fuel cells, solid oxide fuel cells,

To sulfur recovery system

and fuel synthesis. At the Central Research Institute of Electric Power Industry (CRIEPI), a desulfurization agent using zinc

Coal gas

To gas turbine

ferrite (ZnFe2O4), a double oxide of iron and zinc, has been

2.Technology

developed and found capable of reduction to 1ppm or less, now

(1)Dry desulfurization method

Members in charge of research and development: Center for Coal Utilization, Japan; IGCC Research Association; Technology Research Association for Molten Carbonate Fuel Cell Power Generation System; Central Research Institute of Electric Power Industry; Electric Power Development Company; Ishikawajima-Harima Heavy Industries Co., Ltd.; Mitsubishi Heavy Industries, Ltd.; Kawasaki Heavy Industries, Ltd. Kind of project: Voluntary project /NEDO-commissioned business Development period: 1986-1998

being at the stage of real-gas validation. Efforts to cope with air-

1. Regeneration tower 2. Reduction tower 3. Desulfurization tower

blown entrained-bed gasification gas have so far been the main theme of review while another important problem is adaptation to high-carbon monoxide concentration gas like oxygen-blown gasification gas which degrades the desulfurication agent by

Fig.5 Moving-Bed Combined Dust Collection-Desulfurization Process

allowing carbon to be separated out in it.

Outline

Nakoso IGCC Pilot Plant Project (for coal gas production of

It is a method in which, as shown in Fig. 2, metal oxides are

43,600m3N/h in amount), a pilot plant that can treat the amount

(2)Dry dehalogenation method

reduced by coal gasification gas, and reduced metal oxides

of coal gas produced by a tenth and is under verification of

remove sulfur compounds from gas, then are converted to

performance. Meanwhile, Kawasaki Heavy Industries, Ltd. has

Members in charge of research and development: Central Research Institute of Electric Power Industry Kind of project: Voluntary project

sulfides. This method can be used more than once by letting

developed an iron oxide-based highly wear-resistant granular

sulfides react with oxygen for the release of sulfur contents as

desulfurization agent for use in a moving-bed combined-

Outline

SO2 to bring back metal oxides.

desulfurization/dust collection system (Fig.5) and evaluated its

For the use of coal gasification gas in molten carbonate/solid

The development of this method as a technology for integrated

performance at the pilot plant capable of treating the 1/40 amount

oxide fuel cells and fuel synthesis, it is necessary to remove not

gasification combined-cycle power generation (IGCC) was

of coal gas produced, which was buiilt under the 200-Ton/Day

only soot/dust and sulfur compounds but also halogen

promoted, targeting to reduce sulfur oxides to 100ppm or less in

compounds.

the temperature range of 400-500 C where economical carbon

For the adaptation to these technologies, efforts are under way

O

Reduction

steel can be used for piping. As the metal oxide to be used, iron oxide was selected and Ishikawajima-Harima Heavy Industries

Desulfurization agent carrier

1ppm or less. At present, a method to remove HCl/HF contents of gas as NaCl/NaF, using a sodic compound is under development. CRIEPI test-made a sodium aluminate (NaAlO2)based absorbent, confirming possible reduction to 1ppm or less, but such efforts still remain on a laboratory scale as well as developing stage. This method faces an important problem of

to develop a halide absorption agent capable of reduction to

how the absorbent should be reproduced or recycled.

Mt: Elementary metal

Co., Ltd. built a fluidized-bed desulfurization pilot plant (Fig.3) that can treat the total amount of coal gas, using 100-200- m

References

iron ore particles, and is now under verification for performance, under the 200-Ton/Day Nakoso IGCC Pilot Plant Project (19911995).

Reproduction

On the other hand, the Central Research Institute of

Desulfurization

Electric Power Industry and Mitsubishi Heavy Industries, Ltd. , assuming its use in fixed-bed desulfurization systems (Fig.4), have jointly developed an iron oxide-based honeycomb

1) Nakayama et al, "Development State of 3 Dry Gas Cleanup Methods in Dry Gas Cleanup Technology Development for Integrated Gasification Combined-Cycle Power Generation", the Japan Institute of Energy Journal, Vol. 75, No. 5, 1996 2) Shirai et al, "Coal Gasification Gas-Based Fixed-Bed Dry Desulfurization Technology Development", the Society of Powder Technology, Japan’s journal, Vol. 40, No. 8, 2003 3) M. Nunokawa et al, "Developments of Hot Coal Gas Desulfurization and Dehalide Technologies for IG-MCFC Power Generation System", CEPSI proceedings 2002 Fukuoka

Fig. 2 Desulfurization Reaction Cycle

desulfurization agent. They also built, under the 200-Ton/Day

81

82

Part2 Outline of CCT Clean Coal Technologies in Japan

Environmental Protection Technologies (Flue Gas Treatment and Gas Cleaning Technologies)

4B5. Gas Cleaning Technology

To dust collector

Coal gas (from dust collector)

Cyclone Desulfurization agent

1.Background For solution of problems with such a wet gas purification method,

generation and fuel synthesis technologies, it is necessary to

efforts are now exercised to develop dry gas purification

Air

SOx reduction tower

Reproduction tower

Sulfur condenser

Desulfurization tower

For the development of coal gasification gas-based power

Heat exchanger

Anthracite

Outline of technology

Desulfurization process Reduction process

Ceramic filter

technology is found in the wet gas purification method which, after

COS conversion catalyst

Scrubber (dehalogenation, deammonification)

Carrier

Ash

Gas in excess

Fig.4 Fixed-Bed Desulfurization Process

Sulfur

Coal gas

Separator

scrubber, desulfurizes the gas with a methyldiethylamine (MDEA)

Soot/dust filter

Fig.3 Fluidized-Bed Desulfurization Process

or other amine-based liquid absorbent for gas purification. This

Distributor

method, however, requires the gas to be cooled down to around room temperature, thus losing much heat.

Reduction process

To gas turbine

Coal gasifier

removing water-soluble halides and other contents by a water

Sulfur recovery equipment

Sulfur

Air

remove sulfur compounds (H2S, COS), halides (HCl, HF), and other gas contents. As shown in Fig.1 a main application of this

Gas for sulfur reduction

Dust filter

Sulfur recovery equipment

Furthermore, the

Nakoso Pilot Plant Project.

This fact indicates that IGCC-

Soot/dust

dedicated technologies have already reached their validation

To sulfur recovery system

stage.

process becomes complex since it requires not only a heat H 2S absorption tower

exchanger but also a catalyst which changes hard-to-remove COS into H2S. It is also difficult to precisely reduce sulfur compounds to a 1-ppm level.

Renewal tower Reboiler

Fig. 1 Wet Gas Purification Process

Air

At present, a desulfurization agent that can reduce sulfur compounds to a 1ppm level is under development for use in such

Reduction gas (coal gas)

applications as molten carbonate fuel cells, solid oxide fuel cells,

To sulfur recovery system

and fuel synthesis. At the Central Research Institute of Electric Power Industry (CRIEPI), a desulfurization agent using zinc

Coal gas

To gas turbine

ferrite (ZnFe2O4), a double oxide of iron and zinc, has been

2.Technology

developed and found capable of reduction to 1ppm or less, now

(1)Dry desulfurization method

Members in charge of research and development: Center for Coal Utilization, Japan; IGCC Research Association; Technology Research Association for Molten Carbonate Fuel Cell Power Generation System; Central Research Institute of Electric Power Industry; Electric Power Development Company; Ishikawajima-Harima Heavy Industries Co., Ltd.; Mitsubishi Heavy Industries, Ltd.; Kawasaki Heavy Industries, Ltd. Kind of project: Voluntary project /NEDO-commissioned business Development period: 1986-1998

being at the stage of real-gas validation. Efforts to cope with air-

1. Regeneration tower 2. Reduction tower 3. Desulfurization tower

blown entrained-bed gasification gas have so far been the main theme of review while another important problem is adaptation to high-carbon monoxide concentration gas like oxygen-blown gasification gas which degrades the desulfurication agent by

Fig.5 Moving-Bed Combined Dust Collection-Desulfurization Process

allowing carbon to be separated out in it.

Outline

Nakoso IGCC Pilot Plant Project (for coal gas production of

It is a method in which, as shown in Fig. 2, metal oxides are

43,600m3N/h in amount), a pilot plant that can treat the amount

(2)Dry dehalogenation method

reduced by coal gasification gas, and reduced metal oxides

of coal gas produced by a tenth and is under verification of

remove sulfur compounds from gas, then are converted to

performance. Meanwhile, Kawasaki Heavy Industries, Ltd. has

Members in charge of research and development: Central Research Institute of Electric Power Industry Kind of project: Voluntary project

sulfides. This method can be used more than once by letting

developed an iron oxide-based highly wear-resistant granular

sulfides react with oxygen for the release of sulfur contents as

desulfurization agent for use in a moving-bed combined-

Outline

SO2 to bring back metal oxides.

desulfurization/dust collection system (Fig.5) and evaluated its

For the use of coal gasification gas in molten carbonate/solid

The development of this method as a technology for integrated

performance at the pilot plant capable of treating the 1/40 amount

oxide fuel cells and fuel synthesis, it is necessary to remove not

gasification combined-cycle power generation (IGCC) was

of coal gas produced, which was buiilt under the 200-Ton/Day

only soot/dust and sulfur compounds but also halogen

promoted, targeting to reduce sulfur oxides to 100ppm or less in

compounds.

the temperature range of 400-500 C where economical carbon

For the adaptation to these technologies, efforts are under way

O

Reduction

steel can be used for piping. As the metal oxide to be used, iron oxide was selected and Ishikawajima-Harima Heavy Industries

Desulfurization agent carrier

1ppm or less. At present, a method to remove HCl/HF contents of gas as NaCl/NaF, using a sodic compound is under development. CRIEPI test-made a sodium aluminate (NaAlO2)based absorbent, confirming possible reduction to 1ppm or less, but such efforts still remain on a laboratory scale as well as developing stage. This method faces an important problem of

to develop a halide absorption agent capable of reduction to

how the absorbent should be reproduced or recycled.

Mt: Elementary metal

Co., Ltd. built a fluidized-bed desulfurization pilot plant (Fig.3) that can treat the total amount of coal gas, using 100-200- m

References

iron ore particles, and is now under verification for performance, under the 200-Ton/Day Nakoso IGCC Pilot Plant Project (19911995).

Reproduction

On the other hand, the Central Research Institute of

Desulfurization

Electric Power Industry and Mitsubishi Heavy Industries, Ltd. , assuming its use in fixed-bed desulfurization systems (Fig.4), have jointly developed an iron oxide-based honeycomb

1) Nakayama et al, "Development State of 3 Dry Gas Cleanup Methods in Dry Gas Cleanup Technology Development for Integrated Gasification Combined-Cycle Power Generation", the Japan Institute of Energy Journal, Vol. 75, No. 5, 1996 2) Shirai et al, "Coal Gasification Gas-Based Fixed-Bed Dry Desulfurization Technology Development", the Society of Powder Technology, Japan’s journal, Vol. 40, No. 8, 2003 3) M. Nunokawa et al, "Developments of Hot Coal Gas Desulfurization and Dehalide Technologies for IG-MCFC Power Generation System", CEPSI proceedings 2002 Fukuoka

Fig. 2 Desulfurization Reaction Cycle

desulfurization agent. They also built, under the 200-Ton/Day

81

82

Part2 Outline of CCT Environmental Protection Technologies (CO2 Recovery Technologies)

Clean Coal Technologies in Japan

In charge of research and development: Center for Coal Utilization, Japan; National Institute of Advanced Industrial Science and Technology; Ishikawajima-Harima Heavy Industries Co., Ltd.; Babcook Hitachi K.K.; Mitsubishi Materials Corporation; JGC Corporation Project type: Subsidized by the Ministry of Economy, Trade and Industry Period: 2000-2010

Ca(OH)2 in the furnace is employed. Gasification at a temperature

Cold gas efficiency HyPr-RING Process gasifies an easy-to-gasify portion under

as low as possible is also employed to prevent eutectic melting of

low-temperature (600-700 C) conditions into hydrogen and

calcium minerals. In such cases, unreacted product carbon can be

uses the remaining hard-to-react char as fuel for CaCO3

used as a heat source for CaO reproduction.

O

calcination.

Coal 1,000t/d

In such cases, recovery of pure CO2 requires its burning with

Methane reforming

4C1. Hydrogen Production by Reaction Integrated Novel Gasification Process (Hypr-RING)

3.Characteristics of HyPr-RING Process

Mixing

oxygen. Fig. 3 shows an example of process configuration with

Rock hopper

Heat exchange Cyclone

a fluidized bed gasifier and an internal combustion-type

Outline of Technology

calcining furnace. For product gas composition of 95% H2 and 5% CH4, the cold gas efficiency proved about 0.76.

Coal, the world’s most abundantly reserved energy resources, is

and more efficiently, particularly, a technology contributing to CO2

used as important primary energy due to its excellence in economic

reduction. HyPr-RING Process is now under development for

Absorbent CaO

terms as well. Its consumption is expected to increase with the

commercialization as a technology which, in an attempt to answer

At the gasifier inlet, where temperature is low, CaO first reacts

growth of economy as well as increasing population in the future.

such a claim, enables hydrogen necessary for future hydrogen-

with H2O to produce Ca(OH)2, providing heat to coal pyrolysis.

Meanwhile, solution of global environment problems, to begin with

energy communities to be produced from coal and supplied.

Then, at a high-CO2 partial pressure region, Ca(OH)2 absorbs

Heat exchange Gasifier

the global warming due to CO2, has become a task assigned to

CO2 to produce CaCO3, releasing heat. This heat is used for

human beings, earnestly claiming a technology to use coal clean

the gasification of char.

Water vapor

Cold gas efficiency 0.76

temperature sintering, a method of absorbing CO2 by way of

HyPr-RING Process is a process in which a CO2-absorbent CaO

What is difference from Conventional gasification?

is directly added into the coal gasifier and the CO2 thus produced

Conventional gasification secures the heat necessary for

is fixed as CaCO3 to finish preparing hydrogen within a furnace.

gasification by partial combustion of coal, with a reaction

4.Outline of project

The reaction between CaO and H2O causes heat so that the heat

expressed by the following equation taking place in the gasifier:

Under this project that started in 2000, process configuration

necessary for reaction is internally supplied in the furnace as a

Steam turbine

Fig. 3 Analysis of HyPr-RING process

Table 1 Targets

identification and FS through testing with batch/semi-continuous

great merit from a thermal point of view. Within the furnace, a

One mole of input coal carbon gives about 1 mole of hydrogen

equipment were paralleled with a variety of factor tests required.

series of reactions from Equation (1) to Equation (4) and the

(including that producible from CO).

For this, however,

In and after 2003, it is expected that 50-kg/d (coal base) continuous

overall reaction of Equation (5) take place.

gasification gas must be sent through a low-temperature shifter

test equipment will be fabricated for continuous testing and then,

and then exposed to a low-temperature absorbent such as amine

based on the results, running tests and FS of a 0.5-1t/d-scale bench

for CO2 separation.

plant are to be carried out in and after 2006 for its established

At that time, the amount of CO2 gas

O2 separation

Coal supply 1,000t/d Heating value 6,690kcal/kg

To prevent CaO from becoming less active due to high2.Theory of HyPr-RING Process

Calcining

1.Background

separated is 1 mole per mole of hydrogen.

commercialization process. Table 1 shows development targets of

On the other hand, HyPr-RING Process uses dry CaO to absorb

the project and Table 2 shows, the scheduleof the project.

Item

Target

1. Gasification efficiency 2. Product gas purity 3. CO2 recovery

1. Cold gas efficiency: 75% or more 2. Sulfur contents of product gas: 1ppm or less 3. High-purity CO2 recovery rate: 40% or more of input coal carbon to be recovered (per-unit of energy CO2 exhaust to be less than that from natural gas)

CO2 in the furnace (650 C, 30atm). In this case, heat is released O

This means there is no need of

Here, post-CO2 absorption CaCO3 is returned to CaO by

external heat in theory. It is also found that CO2 fixation shifts

calcination (reproduction) and, at that time, 50-80% of thermal

the reactions (2) and (3) to H2 generation.

energy required changes into chemical energy of CaO for reuse

Fig. 1 shows the process concept of HyPr-RING. Product CaCO3

in the gasifier (Fig. 2).

is reproduced by calcining into CaO for its recycle as an absorbent.

As seen from Equation (5), 2-mol hydrogen production from 1

Most of the heat energy required for calcining is carried as

mol of carbon is another important feature.

chemical energy of CaO and made available for the reaction to give H2 in the furnace.

Item

2000

2001

2002

2003

2004

2005

2006

2007

2008

(1)Fundamental test (2)Acquisition of design data (3)50-kg/d test facility (4) 500-kg/d PDU (5)FS Pilot plant test (moving to the 2nd phase)

References

1) Shiying Lin, Zenzo Suzuki & Hiroyuki Hatano, Patent No. 29791-49 (1999) 2) Energy Technology and the Environment, Editors: A. Bisio and S. Boots, John Wiley & Sons, New York, 1995 Fig. 1 Concept of HyPr-RING process

Fig. 2 Hydrogen production using HyPr-RING process. 83

2009

84

Final evaluation

CaO as starting reactants.

Table 2 Development Schedule

Pre-final evaluation

temperature in the gasifier .

Mid-term evaluation

with CO2 absorption and made available for maintaining high This overall reaction is an exothermic reaction with C, H2O, and

2010

Part2 Outline of CCT Environmental Protection Technologies (CO2 Recovery Technologies)

Clean Coal Technologies in Japan

In charge of research and development: Center for Coal Utilization, Japan; National Institute of Advanced Industrial Science and Technology; Ishikawajima-Harima Heavy Industries Co., Ltd.; Babcook Hitachi K.K.; Mitsubishi Materials Corporation; JGC Corporation Project type: Subsidized by the Ministry of Economy, Trade and Industry Period: 2000-2010

Ca(OH)2 in the furnace is employed. Gasification at a temperature

Cold gas efficiency HyPr-RING Process gasifies an easy-to-gasify portion under

as low as possible is also employed to prevent eutectic melting of

low-temperature (600-700 C) conditions into hydrogen and

calcium minerals. In such cases, unreacted product carbon can be

uses the remaining hard-to-react char as fuel for CaCO3

used as a heat source for CaO reproduction.

O

calcination.

Coal 1,000t/d

In such cases, recovery of pure CO2 requires its burning with

Methane reforming

4C1. Hydrogen Production by Reaction Integrated Novel Gasification Process (Hypr-RING)

3.Characteristics of HyPr-RING Process

Mixing

oxygen. Fig. 3 shows an example of process configuration with

Rock hopper

Heat exchange Cyclone

a fluidized bed gasifier and an internal combustion-type

Outline of Technology

calcining furnace. For product gas composition of 95% H2 and 5% CH4, the cold gas efficiency proved about 0.76.

Coal, the world’s most abundantly reserved energy resources, is

and more efficiently, particularly, a technology contributing to CO2

used as important primary energy due to its excellence in economic

reduction. HyPr-RING Process is now under development for

Absorbent CaO

terms as well. Its consumption is expected to increase with the

commercialization as a technology which, in an attempt to answer

At the gasifier inlet, where temperature is low, CaO first reacts

growth of economy as well as increasing population in the future.

such a claim, enables hydrogen necessary for future hydrogen-

with H2O to produce Ca(OH)2, providing heat to coal pyrolysis.

Meanwhile, solution of global environment problems, to begin with

energy communities to be produced from coal and supplied.

Then, at a high-CO2 partial pressure region, Ca(OH)2 absorbs

Heat exchange Gasifier

the global warming due to CO2, has become a task assigned to

CO2 to produce CaCO3, releasing heat. This heat is used for

human beings, earnestly claiming a technology to use coal clean

the gasification of char.

Water vapor

Cold gas efficiency 0.76

temperature sintering, a method of absorbing CO2 by way of

HyPr-RING Process is a process in which a CO2-absorbent CaO

What is difference from Conventional gasification?

is directly added into the coal gasifier and the CO2 thus produced

Conventional gasification secures the heat necessary for

is fixed as CaCO3 to finish preparing hydrogen within a furnace.

gasification by partial combustion of coal, with a reaction

4.Outline of project

The reaction between CaO and H2O causes heat so that the heat

expressed by the following equation taking place in the gasifier:

Under this project that started in 2000, process configuration

necessary for reaction is internally supplied in the furnace as a

Steam turbine

Fig. 3 Analysis of HyPr-RING process

Table 1 Targets

identification and FS through testing with batch/semi-continuous

great merit from a thermal point of view. Within the furnace, a

One mole of input coal carbon gives about 1 mole of hydrogen

equipment were paralleled with a variety of factor tests required.

series of reactions from Equation (1) to Equation (4) and the

(including that producible from CO).

For this, however,

In and after 2003, it is expected that 50-kg/d (coal base) continuous

overall reaction of Equation (5) take place.

gasification gas must be sent through a low-temperature shifter

test equipment will be fabricated for continuous testing and then,

and then exposed to a low-temperature absorbent such as amine

based on the results, running tests and FS of a 0.5-1t/d-scale bench

for CO2 separation.

plant are to be carried out in and after 2006 for its established

At that time, the amount of CO2 gas

O2 separation

Coal supply 1,000t/d Heating value 6,690kcal/kg

To prevent CaO from becoming less active due to high2.Theory of HyPr-RING Process

Calcining

1.Background

separated is 1 mole per mole of hydrogen.

commercialization process. Table 1 shows development targets of

On the other hand, HyPr-RING Process uses dry CaO to absorb

the project and Table 2 shows, the scheduleof the project.

Item

Target

1. Gasification efficiency 2. Product gas purity 3. CO2 recovery

1. Cold gas efficiency: 75% or more 2. Sulfur contents of product gas: 1ppm or less 3. High-purity CO2 recovery rate: 40% or more of input coal carbon to be recovered (per-unit of energy CO2 exhaust to be less than that from natural gas)

CO2 in the furnace (650 C, 30atm). In this case, heat is released O

This means there is no need of

Here, post-CO2 absorption CaCO3 is returned to CaO by

external heat in theory. It is also found that CO2 fixation shifts

calcination (reproduction) and, at that time, 50-80% of thermal

the reactions (2) and (3) to H2 generation.

energy required changes into chemical energy of CaO for reuse

Fig. 1 shows the process concept of HyPr-RING. Product CaCO3

in the gasifier (Fig. 2).

is reproduced by calcining into CaO for its recycle as an absorbent.

As seen from Equation (5), 2-mol hydrogen production from 1

Most of the heat energy required for calcining is carried as

mol of carbon is another important feature.

chemical energy of CaO and made available for the reaction to give H2 in the furnace.

Item

2000

2001

2002

2003

2004

2005

2006

2007

2008

(1)Fundamental test (2)Acquisition of design data (3)50-kg/d test facility (4) 500-kg/d PDU (5)FS Pilot plant test (moving to the 2nd phase)

References

1) Shiying Lin, Zenzo Suzuki & Hiroyuki Hatano, Patent No. 29791-49 (1999) 2) Energy Technology and the Environment, Editors: A. Bisio and S. Boots, John Wiley & Sons, New York, 1995 Fig. 1 Concept of HyPr-RING process

Fig. 2 Hydrogen production using HyPr-RING process. 83

2009

84

Final evaluation

CaO as starting reactants.

Table 2 Development Schedule

Pre-final evaluation

temperature in the gasifier .

Mid-term evaluation

with CO2 absorption and made available for maintaining high This overall reaction is an exothermic reaction with C, H2O, and

2010

Part2 Outline of CCT Environmental Protection Technologies (CO2 Recovery Technologies)

4C2. CO2 Recovery and Sequestration Technology Outline of technology

1.CO2 recovery technology (1) CO2 recovery technology (for natural gas, syngas, and

global warming, which can never be prevented unless CO2 release into

exhaust gas)

air is mitigated. There are, however, many difficulties in recovering and

CO2 separation/recovery widely prevails in natural gas and syngas sectors

sequestrating CO2 from movable bodies such as automobiles and

and already has a decades-long history. CO2 contents of natural gas are not

vessels, naturally rendering it easier to recover CO2 from boilers, gas

only useless themselves because of making natural gas less caloric but also

turbines, and other fixed sources.

trouble LNG/ethane recovery plants by solidifying CO2 into dry ice. CO2 is

(3) Characteristics and superiority of technology to recover CO2

hence removed to prevent such troubles.

from exhaust gas

In a plant where natural gas or naphtha is reformed to manufacture H2, CO2

The Kansai Electric Power Co., Inc. and Mitsubishi Heavy Industries,

is separated after converted from the CO produced with hydrogen as

Ltd. started in 1999 a joint R&D program to recover CO2 from exhaust

syngas. In an ammonia/urea plant, CO2 is separated from the gas mixture of

gas of power plants and other facilities as a measure against the global

H2, N2, and CO2 to produce urea, using H2/N2-derived synthetic ammonia

warming. First, they assessed the conventional "monoethanolamine

and separated CO2.

(MEA) liquid absorbent-based technology considered at that time a

Previously, however, CO2 separation/recovery from exhaust gas was not in

CO2 recovery process that could save the largest amount of energy. It

so large demand, finding limited applications only in food/dry ice production.

is a process developed by former Dow Chemical Co. and later

In case that CO2 is separated from natural gas or syngas, the separation is

assigned to Fluor Daniel, Inc. This MEA-based technology was found

relatively easy because of a high gas pressure while CO2

disadvantageous for use in large plants as a measure against the

separation/recovery from exhaust gas is difficult in many technological

global warming because of such problems as a large amount of energy

respects due to a very low level of exhaust gas pressure as well as oxygen,

required for CO2 recovery and a great loss in the liquid absorbent due

SOx, NOx, and soot/dust that are contained in exhaust gas.

to its rapid deterioration. Kansai Electric Power and Mitsubishi Heavy

(2) Necessity to recover CO2 from fixed sources

Industries started with basic research to explore a new liquid absorbent,

Most of fossil fuel (oil, natural gas, and coal) in the world is used as fuel

resulting in successful development of a novel energy-saving and

of boilers, gas turbines, and internal combustion engines, releasing

uneasier-to-be-deteriorated/-lost liquid absorbent, which has already

CO2 into the atmosphere as exhaust gas. As a result, it is alleged that

been put into practice for urea manufacture in Malaysia.

the atmospheric concentration of CO2 has increased to cause the 2.CO2 sequestration technology As for methods of CO2 sequestration, geological sequestration and

in these cavities, which indigenously contains water (mainly salt water),

ocean sequestration are widely studied and a commercial project of the

by pressing in it there to replace water. This has already started in

former has already started.

Norway.

Geological sequestration of CO2 is practiced, using the Enhanced Oil

distributed over continental shelves is considered the most realistic.

For Japan, Norway-like CO2 sequestration into aquifers

Recovery (EOR) method or the coal seam sequestration-accompanied

Other than into aquifers, CO2 can also be sequestrated into closed

Coal Bed Methane Recovery method but, if intended only for CO2

oil/gas fields where production had already terminated. Closed oil/gas

sequestration, methods of aquifer sequestration and sequestration into

fields may, since their ceilings are so geologically structured from ancient

closed oil/gas fields may also be used. Fig. 1 shows a conceptual view

times as not to permit any oil/gas leaks for possible formation of oil/gas

of CO2 recovery - EOR combination.

wells, be CO2 containment-secured locations for pressing in CO2

CO2-EOR commercialization started in the 1970’s mainly in the United States, realizing the present enhanced oil production of about 200 thousand barrels a day. Outside the United States, such practice is also witnessed in Canada, Turkey, and Hungary. In terms of by-application consumption, EOR purposes are the largest in fact. Underground aquifers are widely distributed wherever on the earth sedimentary layers are located. Even in Japan, where aquifers are scarce and, if any, small in structure because it is a volcanic country and, therefore, a country of earthquakes, surveys are under way, seeking the possibility of CO2 sequestration. If a geological underground layer has cavities, CO2 can be sequestrated

Photo 1 Conceptual View of Practice to Recover CO2 from Power Plant Exhaust Gas for EOR

Reference

Masaki Iijima et al, "CO2 Recovery/Effective Utilization/Fixation and Commercialization", MHI Technical Journal, 39(5), 286 (2002) 85

Clean Coal Technologies in Japan

4C3. CO2 Conversion Technology Outline of technology

1.Urea production At present, urea is manufactured by synthesizing ammonia with inexpensive natural gas as its main material to use this ammonia with the CO2 derived as off-gas at that time for synthesis of urea. When urea is synthesized with natural gas as raw material, however, CO2 may sometimes be short in view of the balance between ammonia and off-gas CO2.

In such cases, CO2 is

recovered from exhaust gas of the steam reformer, which manufactures hydrogen and CO from natural gas, for the supply to urea synthesis to adjust the ammonia-CO2 balance, thereby enabling urea to be produced in largest quantities. The plant Mitsubishi Heavy Industries, Ltd. delivered to Malaysia PETRONAS Fertilizer Sdn. Bhd. matches this purpose. Photo 1 shows the appearance of this plant. Photo 1 Total view of Plant

2.Methanol production Methanol is now also manufactured mainly with natural gas as

steam reformer exhaust gas to optimize the H2:CO ratio for

raw material. If H2 and CO are synthesized by steam-reforming

methanol synthesis, thereby enhancing methanol production.

natural gas, then the H2:CO ratio is 3:1. On the other hand, for methanol synthesis, the best H2:CO ratio is 2:1 but the output of methanol can be maximized through the recovery of CO2 from

CO2

steam reformer exhaust gas to add a worthwhile amount of CO2 in carbon contents within the process.

CO2 recovery

Exhaust gas Natural gas Syngas Steam reformer compressor Steam

At present, active

planning for CO2 addition is under way to improve the production capacity of Saudi Arabian methanol plants.

Methanol synthesis

Methanol

Fuel

Fig. 1 shows a system where, in the process to produce

Fig. 1 System to recover CO2 from exhaust gas for enhanced methano production in a methanol plant

methanol with natural gas as raw material, CO2 is recovered from

3.DME (dimethylether) production DME is currently synthesized by way of methanol. The process uses a system similar to that for the above-mentioned methanol

CO2

production.

CO2 recovery

Exhaust gas Natural gas Syngas Steam reformer compressor Steam

Methanol synthesis

DME DME synthesis

Fuel

Fig. 2 CO2 recovery from exhaust gas-integrated DME production system

4.GTL production GTL is the acronym of Gas to Liquid generally referring to a process to synthesize kerosene and light oil by Fischer-Tropsch CO2

Method (FT Method). For this GTL synthesis, it is necessary to

CO2 recovery

Exhaust gas Natural gas Syngas Steam reformer compressor Steam

adjust the H2:CO ratio to 2:1 like in the case with methanol and the same recovery of CO2 from steam reformer exhaust gas for its input within the process system as in methanol production

FT Synthesis

Liquid fuel

Fuel

enables the H2:CO ratio to be adjusted.

Fig. 3 CO2 recovery from exhaust gas-integrated liquid fuel production system

The method used for the system as a whole, however, recycles CO2 not contributing to the reaction from FT Synthetic System to the stream before the steam reformer.

Reference

Masaki Iijima et al, "CO2 Recovery/Effective Utilization/Fixation and Commercialization", MTI Technical Journal, 39(5), 286 (2002) 86

Part2 Outline of CCT Environmental Protection Technologies (CO2 Recovery Technologies)

4C4. Oxy-fuel Combustion (Oxygen-firing of conventional PCF System) In charge of research and development: Center for Coal Utilization, Japan; Electric Power Development Co., Ltd.; Ishikawajima-Harima Heavy Industries, Co., Ltd.; Nippon Sanso Corp.; and Institute of Research and Innovation Project type: Coal Production and Utilization Technology Promotion Grant Period: 1992-2000 (8 years)

Outline of technology

1.Background and process outline Efforts of reduction in CO2 emissions have been promoted over the

from large scale coal-fired power plants.

world responding to the issues of global warming in recent years.

Ordinary coal-fired power plants combust coal by air. Since air

Specifically, coal is known as a source of heavy emissions of

contains N2 by 79%, all of the N2 is emitted to atmosphere during

environmental loading substances (SOx, NOx, CO2, etc.), though

the combustion process, thus the CO2 concentration in the

the coal is expected as a sustainable energy resource also in the

combustion flue gas is only 13-15% level. The oxygen combustion

future. Since coal generates large quantity of CO2 per unit calorific

technology is a process to separate oxygen from the combustion

value, research and development of the CO2 recovery and CO2

air and to directly combust the coal with thus separated oxygen to

separation technologies are in progress on various points of views.

increase the CO2 concentration in the flue gas to 90% or more,

With the background, the study team focused on the development

then to recover the flue gas in that state (refer to Fig. 1.)

of technology to recover CO2 from coal-fired power plants utilizing

Furthermore, the study team investigated a CO2 recovery system

oxygen (O2/CO2) combustion, and has promoted the research of

applying oxygen-blow IGCC aiming to further increase the

CO2 recovery technology.

efficiency.

The CO2 recovery in the oxygen

combustion stage is a hopeful technology of direct CO2 recovery

Ordinary recovery process

Recovery process using oxygen combustion Stack

Coal

Coal Air

Boiler

Dust removal

Desulfurization

CO2 separation and recovery

Air separator

Compressor Boiler

Dust removal

Air Compressor

O2/CO2

Flue gas recycle

Recovered CO2

Recovered CO2 Fig. 1 Comparison of CO2 recovery between oxygen combustion process and ordinary air combustion process

2.Result of the development Efforts of reduction in CO2 emissions have been promoted over the

of technology to recover CO2 from coal-fired power plants utilizing

world responding to the issues of global warming in recent years.

oxygen (O2/CO2) combustion, and has promoted the research of

Specifically, coal is known as a source of heavy emissions of

CO2 recovery technology.

environmental loading substances (SOx, NOx, CO2, etc.), though

combustion stage is a hopeful technology of direct CO2 recovery

the coal is expected as a sustainable energy resource also in the

from large scale coal-fired power plants.

future. Since coal generates large quantity of CO2 per unit calorific

Ordinary coal-fired power plants combust coal by air. Since air

value, research and development of the CO2 recovery and CO2

contains N2 by 79%, all of the N2 is emitted to atmosphere during

separation technologies are in progress on various points of views.

the combustion process, thus the CO2 concentration in the

With the background, the study team focused on the development

combustion flue gas is only 13-15% level. The oxygen combustion

87

The CO2 recovery in the oxygen

Clean Coal Technologies in Japan

technology is a process to separate oxygen from the combustion

CO2 recovery type oxygen pulverized coal combustion power plant

air and to directly combust the coal with thus separated oxygen to increase the CO2 concentration in the flue gas to 90% or more, then to recover the flue gas in that state (refer to Fig. 1.) Furthermore, the study team investigated a CO2 recovery system applying oxygen-blow IGCC aiming to further increase the

CO2 underground disposal

Boiler

efficiency.

Oxygen production facility CO2 tank

CO2 ocean disposal

Fig. 2 Image-drawing of CO2 recovery type power plant applying oxygen combust

3.Issues and feasibility to practical application Regarding the CO2 recovery type oxygen combustion power

the global warming and for reducing the CO2 emissions, though

generation system and the CO2 recovery type IGCC, the study

there are technologically validating issues such as the safety of

team conducted research and development and has proposed a

power generation system with the oxygen combustion and the

power generation system which has superiority in terms of

operability of CO2 recovery type IGCC.

performance and economy as a CO2 recovery technology.

In

application of the system, positive study should be conducted on

addition, in the basic combustion test, the study team has acquired

the basis of the obtained results, while studying the application of

academically valuable results (including the effect of reduction in

the CO2 recovery type oxygen pulverized coal combustion system

NOx emissions).

and of the CO2 recovery type IGCC, respectively, for the cases of

It should be emphasized to further promote the study for controlling

application of CO2 recovery to an existing plant and of new plant.

As for the practical

Recovered CO2 CO2 compression

CO2

Coal Gasification

CO2

H 2O

CO2

CO CO-shift reaction

Gas purification

H2

H2

H2

CO2 removal

H 2O

Steam

Air

Air

N2

Air separation Air combustion gas turbine

Bleed

Fig. 3 CO2 recovery type IGCC system

References

1) Hiromi Shimoda: Proceeding of the 10th Coal Utilization Technology Conference, p.211 (2000) 2) S. Amaike: Proceeding of the 5th ASME/JSME Joint Thermal Engineering Conference, "AJTE99-6410" (1999) 88

N2 HRSG

Part2 Outline of CCT Basic Technologies for Advanced Coal Utilization

5A1. Modelling and Simulation Technologies for Coal Gasification In charge of research and development: Center for Coal Utilization, Japan Project type: NEDO-commissioned project

Outline of technology

1.Outline of basic technology for advanced coal utilization (BRAIN-C) The consumption of fossil fuel compacts on the environment in a

on coal from different angles. In the meantime, numerical

variety of manners. Coal also influences the nature in each of its

simulation is a very effective tool to predict characteristics of a

production, transportation, and utilization processes. In the

pilot or actual production unit from the above-mentioned basic

process of its utilization in particular, coal dust, ash dust, acid gas

data or, in reverse, to evaluate and select useful basic data. With

(NOx, SOx), and carbon dioxide are discharged, suggesting that

this taken into consideration as well, technology development

unregulated guzzling of coal may possibly have a great impact on

under the BRAIN-C is proceeded with from both aspects of useful

the environment. On the other hand, technologies to limit the

basic data retrieval/storage and high-precision numerical

impacts derived from coal utilization on the environment to the

simulation.

minimum, as measures to cope with the above-mentioned

Fig.1 shows "BRAIN-C Technology Map." Products from this

situations, were collectively called Clean Coal Technology (CCT),

project are roughly grouped into the following three categories:

for which advanced R&D is in wide practice in major advanced

(1) Entrained flow gasification simulator

countries including Japan.

(2) Predicted model/parameter correlative equation (3) Coal database

With such circumstances , the "Basic Technology Development Program for Advanced Coal Utilization (BRAIN-C)," mainly

Each category is explained below. Every categories, as integral

targeting at the coal gasification technology and to realize early

part of products from this project, is indispensable for their actual

commercialization of new high-efficiency and clean coal

use in a variety of situations, and ingenious utilization of each in

utilization technologies such as coal gasification and pressurized

accordance with the situation where it is used allows such

fluidized-bed processes, has sought and accumulated basic data

products to be given full play.

Volatilization model

Trace element data CPC actual measurement data

Volatile contents release data

Basic database

Volatile contents database Typical temperature history

Char reaction data Reaction database

Volatile contents composition in quantity al data pic Ty ature r pe tem

Reaction temperature constant

Coal Physicality Physicality database (coal and char) +General analysis +Particle size-surface area +Special analysis CCSEM, XRD, EDS

+ RESORT + FLUENT temTypic pe al da ratur ta e

ter

me

ara

ia

Rad

Heat transmission coefficient Heat transmission test data Particle radiation data

Program Equilibrium model

Gasification simulation code

Parameter correlative equation

p tion

Trace element distribution model

Particle size density fluctuation model

Fig. 1 BRAIN-C Technology Map

89

Adhesion judgment equation Adhesion data

Growth flowage judgment model

Clean Coal Technologies in Japan

2.Entrained flow gasification simulator An entrained flow gasification simulator based on the thermal fluid analysis software (CFD) capable of analyzing flow, reaction, Simulation program (For entrained-flow gasification)

and heat transmission at the same time can calculate temperature

distribution,

ash

adhesion

locations,

gas

Design: Furnace shape Operation: Operational conditions Coal: Property

composition, etc. within a gasifier if given as input data such parameters as reactor shapes, operation conditions,

coal

property and reaction data. It is imaged in Fig. 2 as "Functions of an Entrained Flow Gasification Simulator." Highly reliable prediction results can be used for evaluating operational condition validity, reactor design, and others in advance. The

Pre-test judgment of operational validity

BRAIN-C, developing a coal gasification reaction model shown in Fig. 3 and a particle adhesion model shown in Fig. 4 in basic

Ash adhesion position Temperature distribution CO concentration

CFD, has compared their calculation results with gasifier operation data

in coal-based hydrogen production technology

(HYCOL) to verify the adequacy.

Fig. 2 Functions of Entrained-Flow Gasification Simulator

Gas-phase reaction

Product gas

Volatile contents release speed Oxidizing agent Volatile contents

Fixed carbon Ash

Fixed carbon

Gasification speed Gasification database

Ash

Ash

Fig. 3 Coal Gasification Process Modeling

Particle viscosity

Particle adhesion judgment conditions Judgment value

Reflection Judgment value

Adhesion

Wall ash layer viscosity

Fig. 4 Ash viscosity-Based Adhesion Judgment Model

90

Part2 Outline of CCT Basic Technologies for Advanced Coal Utilization

Fig. 5 shows an example of results from comparison between

temperature and ash viscosity on the wall shown on the right side

the formation position of fused ash layer and the internal

of Fig. 6 are from the result of calculation under operational

condition of gasifier after operations. This found the formation

conditions changed intentionally. For this case, the oxygen ratio

position of fused ash layer calculated with this simulator well-

of the chart top is higher and that of the bottom is lower than

corresponding to the position where the fused ash layer actually

shown on the right side of the figure. In such cases, it was found

existed, endorsing the adequacy of calculation with actual data.

that the temperature of the furnace bottom area goes down (in

Fig. 6 shows the result of case studies on HYCOL using

orange color) and the low-ash-viscosity region (in blue) narrows

gasification simulation. The near-wall temperature and ash

while the upper furnace part becomes hot (the region in red

viscosity on the wall shown on the left side of Fig. 6 are those

increases) to form a region where ash is easier to adhere,

reproduced by calculation under the condition after 1,000-hour

probably spoiling the operating conditions.

operation . The temperature of the furnace bottom area (in red

In this way, using the gasification simulator, analysis can be

color) onto which slag flows down is found high against the low

easily made even if gasification conditions are altered and,

ash viscosity in the region (in blue). The temperature of the upper

therefore, an expectation is growing on its utilization in future

furnace part proves low (in green), giving conditions where

gasification projects.

particles can hardly adhere. On the other hand, the wall-near

Case 3 Forecast value Wall-near temperature Temperature: high Growth of slag

Temperature: low

Throttled section Ash viscosity on the wall The low-viscosity region of the top expands.

Pressure detection terminal Amount of adhesion = amount of slag discharged

A high-viscosity region of the bottom appears.

Molten slag

Fig. 5 Ash Adhesion Position Verification Result

Fig. 6 Simulator-Based Studies

3. Predicted model/parameter correlative equation An entrained-flow gasification simulator is generalized against

generalized volatilization model and the adhesion judgment

various furnace shapes and operational conditions but not

equation are among the tools to prepare parameters. In the

against each coal characteristics. It is, therefore, necessary to

meantime, a trace elements distribution model and an adhesion

input such characteristics into the simulator as a parameter by

judgment equation model are models making judgments from

types of coal. This parameter generally uses the data obtained

simulation results, playing another important role. Under the

from basic test equipment but, in view of quick evaluation, it is

BRAIN-C, thus, prediction equations around a gasification

desirable to establish a means to obtain parameters

simulator have also been developed so that the simulator can be

from

used effectively and quickly.

general analysis of coal or structural physicality data (an advanced model referring as far as to predicted correlative equations and experiment conditions). More specifically, a

91

Clean Coal Technologies in Japan

4.Coal Database The development of a correlative equation or a model indispensably requires physical

and basic experiment data,

including general analysis data. There is, however, a big problem that coal is different in characteristics for different lots arrived 20-liter container (two-shelf)

even if its brand (name of the coal mine) is the same. It was, therefore, first necessary for each of testing bodies, where physical and basic data were obtained, to use completely the same samples of coal. Fig. 7 shows a coal sample bank installed 50-liter container

within the National Institute of Advanced Industrial Science and Technology. Such unified management of analytical test samples has materialized the shipment of identical samples to all testing

Standard Sample Coal Storage Status (AIST)

research bodies. As far as these identical sample-based data are concerned, the measurement of typical data will be completed under this project on 100 kinds of coal for general/special analysis data and, at least 10 kinds of coal, depending upon data items, for basic experiment data. Eventually, all of these measurement data are to be contained in the Internet-accessible coal database. Some of the data so far obtained have already been uploaded to the server of CCUJ for available access or retrieval as shown in Fig. 8. Many of these data are stored in an easy-to-calculate/process Standard Sample Coal (for delivery)

Excel file (see Fig. 9) and can also be downloaded.

Fig. 7 Coal Sample Bank

100 100 kinds kinds of of coal coal General General analysis/special analysis/special analysis analysis

Reaction Reaction data, data, etc. etc.

Reaction Reaction data, data, etc. etc.

Spreadsheet Spreadsheet fileDownload fileDownload

On-line On-line retrieval retrieval Fig. 8 Coal Database

Fig. 9 Basic Data Acquisition

5.Diffusion of basic coal utilization technology products AAn entrained-flow gasification simulator so far developed under

detailed service manuals as well as giving workshops for this

the BRAIN-C is capable of making practical predictions through

purpose to encourage your ingenious utilization of these

the utilization of various models and basic data. The BRAIN-C

products.

Project, soon to meet its final year in 2004, is developing a well-

Despite the coal gasification technology’s predominance in this

equipped system to make a wide choice of programs and basic

development project, those outside gasification projects are

data available so that you can use the products developed under

strongly invited as well to use our simulation code, at least, since

this project to your hearts’ content. We are also preparing

it can be widely used in combustion and other sectors.

92

Part2 Outline of CCT Coproduction System

6A1. Co-generation System Outline of technology

1.Definition of co-generation The system which continuously takes out two or more sources of

convert it into electricity and heat is called a co-generation

secondary energy such as by burning fuel (primary energy) to

system.

2.Co-generation system Co-generation systems are roughly divided into two types. One

The former generally uses liquid or gas fuel and is often found as

is a type which turns a diesel engine, gas engine, gas turbine, or

small-scale equipment for hotels, supermarkets, and hospitals.

other motor to generate power while recovering waste heat of the

As for the latter, every type of fuel including coal is used as fuel

motor as hot water or steam through the thermal exchange at a

for boilers and many are found as relatively large-scale industry-

boiler, etc. and the other generates power by rotating a steam

use thermal power plants. Systems are further grouped into ones

turbine with the steam produced at boilers and, if necessary, take

mainly to supply electricity (condensing turbines) and the others

out steam of desired pressure as process steam.

mainly for steam (heat) supply (back pressure turbines).

Electricity

Jacket cooling water

Hot water

Diesel or gas engine

Waste heat recovery boiler

Heating Hot water supply

Cooling water heat exchanger Steam

Generator

Electricity

Process steam

Stack

Fig.1 Typical Outline of a Diesel Engine/Gas Engine Co-generation System1)

3.Efficiency In general, the power generation efficiency of a coal thermal

commenced its electricity wholesale/supply activities as an

power generation plant which takes out only electricity is around

independent power producer (IPP). Electric power products from

40%. On the other hand, the overall thermal efficiency of a co-

No. 1 Unit already in operation from April, 2002 and No. 2 whose

generation system, which combines its power generation

start of operation is slated for April, 2004 are all to be delivered to

efficiency and heat recovery efficiency, depends upon whether it

the Kansai Electric Power, Inc.

is mainly to supply electricity or mainly to supply heat, with a level

(2)Regional supply of heat

of as high as 80% achieved by the co-generation system mainly

The steam to be used for power generation is partially taken out

for heat supply.

for the supply of maximum 40t/h to 4 nearby sake-brewers. This

(1)Co-generation at a large-capacity coal thermal power plant

amount, accounting for about 2% of the steam generated at

Kobe Steel’s Kobe Power Plant, a large-scale coal thermal power plant of 1,400MW (700MW x 2 generators) in capacity, has

boilers, proves that the share of heat supply is small. The steam generated at multiple boilers of each brewer has so far been put

93

Clean Coal Technologies in Japan

together at the header to be sent to a plant.

At present,

however, with the header as a point of competitive taking, steam extracted after working at turbines is directly supplied to brewers in an attempt to save energy in the region as a whole. (3)Heat supply conditions Turbine extraction steam from a power plant, since it contains trace amounts of hydrazine as an antirust, cannot be directly supplied to brewers with a process where steam directly contacts rice.

The steam (secondary steam) produced

indirectly, using a steam generator operated with turbine extraction steam (primary steam) as the heat source, is supplied to brewers. The outline of a facility is shown in the right.

Full View of Power Plant3)

No.1 power plant Steam Boiler

Turbine

Generator

Extracted Steam Feed water

Cooling water (Sea water)

Primary steam Brewing companies

Backup No.2 power plant

Secondary steam

Sawanotsuru Fukumusume

Steam generator

Hakutsuru Industrial water

Drain cooler Industrial water tank

Gekkeikan

Water supply processing

Fig.2 Outline of Heat Supply Facility4)

References

1) Shibamoto et al: Featured Thermal Power Plant Thermal Efficiency Improvement, Article 3 Thermal Efficiency Management Trend; Thermal Control for a Power Generation System pp1242-1246, Vol. 54, No. 565, Thermal/Nuclear Power Generation (Oct., 2003) 2) The Thermal and Nuclear Power Engineering Society: Introductory Course IV. Industrial-Use Thermal Power Facilities, Etc. pp15391546 Vol. 54, No. 567, Thermal/Nuclear Power Generation (Dec., 2003) 3) Kida et al: Outline of Power Generation Facilities at Kobe Steel’s Kobe Power Plant pp2-7, Vol. 53, No. 2, Kobe Steel Technical Report (Sept., 2003) 4) Miyabe et al: Kobe Steel’s Kobe Power Plant Surplus Steam-Based Heat Supply Facility pp14-18, Vol. 53, No. 2, Kobe Steel Technical Report (Sept., 2003)

94

Part2 Outline of CCT Coproduction System

6A2. Coproduction System Outline of technology

1.Feasibility of fuel coproduction power generation system Conventional work for developing innovative process within a

and assembling peripheral plants to produce various products

single industry faces a limit. To continue further reduction in CO2

enhance the unification of industries centering on the core plant,

emissions, it is necessary to give full scale review of the existing

thus forming a coal industrial complex on the new energy and

energy and materials production systems and to develop

materials production system. As a result, the current industrial

technologies that optimize the individual processes and the

style progresses to the next generation hybrid industrial style

interface between processes not only to improve the conversion

through the unification of industries.

efficiency and to save energy but also to fundamentally and

The core technology of that type of fuel coproduction power

systematically change the energy and materials production

generation system is the coal gasification technology.

systems.

combining the high efficiency power generation system such as

The "fuel coproduction power generation system" which

IGFC with a process to co-produce storable fuel, the

produces power, fuel, and chemicals from coal improves the total

normalization of load to gasification reactor and the significant

energy use efficiency through the unification of industries by

reduction of CO2 emissions are attained.

structuring a coal industrial complex.

Furthermore, waste heat source in the coal industrial complex is

In the fields of power, iron and steel, and chemicals where large

utilized to recover chemicals from coal while conducting

amount of coal is consumed as the energy source, structuring a

endothermic reactions, thus forming further high energy

core plant which produces energy and chemicals simultaneously,

efficiency and upgraded coal industrial complex.

Existed or new facilities steam boiler

Steam

ST GT FC

Gasification Center Coal + Biomass (Waste, waste plastics, oil-base residue, etc.)

Coal

Coal

Power

H2,CO

Fluidized bed gasification furnace

Spouted bed gasification furnace

Thermal decomposition furnace

Process steam H2

Non-reacted gas

fual for heating

for Fuel cell power generation, for Refinery, for Chemical plant

for Hydrogen production

DME market

DME

for Petrochemical plant Propylene C2 distillate C4 distillate

H2,CO

H2

for Hydrogenation and desulfurization at iron works

H2,CO

for Iron works BTX, etc. for Petrochemical plant CH4

Petrochemical plant, gas company Fig.1 Energy Flow

95

By

Clean Coal Technologies in Japan

2. Co-produced fuel and raw materials for chemicals Regarding the fuel and chemicals produced along with the power

the U.S. There are further expectations in producing:

through the coal gasification, there are typical examples of

DME which is applicable to the raw material for clean fuel and for

coproduction by coal gasification in abroad, depending on the

propylene production;

need of relating companies: the production of synthetic fuel

Hydrogen which is expected to increase the demand for the fuel

(GTL) etc. by SASOL group in South Africa; and the production of

of fuel cells and for coming hydrogen-oriented society; and

acetyl chemicals by Eastman Chemical Company in USA. Other

Clean gas for iron works which responds to the changes in

examples of chemicals synthesis by coal gasification include the

energy balance at future iron works.

production of methanol, and of methane, in China, Europe, and

3. Coproduction system The coproduction system produces both materials and energy to

fuel while producing materials shall be emphasized from the

significantly reduce the exergy loss which occurred mainly in

viewpoint of creation of new energy market and also of creation

combustion stage, and to achieve innovative and effective use of

of new industries.

energy.

The coal coproduction system centering on the coal gasification is

That is, the coproduction system is a new production system

able to solve the environmental issues through the significant

which is not only the conventional system which aims to improve

reduction in CO2 emissions by realizing high grade and

the energy conversion efficiency and the cogeneration system

comprehensible coal utilization technology. That type of system

which effectively uses the generated thermal energy as far as

technology development triggers the technological innovation in

possible but also the system to produce both energy and

the coal utilization field, and the strong innovation is expected to

materials to significantly reduce the consumption of energy and

increase the international competitive power and to encourage the

materials.

By making the coproduction system clean, energy

structuring circulation-oriented society. Also in the international

issue and the environmental issue are simultaneously solved and

society, the development of the coproduction system should be an

it should activate economy.

important technological issue to solve the global environmental

Consequently, the coproduction

system that conducts production of energy such as power and

issues. Fuel

Power generation in existing steam turbine power generation system Power Fuel for power generation

Power Steam

IGCC for industrial complex area Private power generation at iron works GT-CC Co-operative Thermal Power Company GT-CC BTX, etc.

Outside sale Steam

Gas Recovered steam

Iron works fuel for heating

Gas,Power,Steam,BTX, etc.

Shift reaction

Coal yard Waste

Process steam fuel for heating

Residue oil

H2/CO > 2 H2 separation Hydrogen

DME production

Non-reacted gas

Fluidized bed gasification reactor

Petroleum industrial complex

Spouted bed gasification reactor Gas Thermal decomposition reactor

Un-recovered gas for Hydrogenation

Outside sale

Fig.2 Power generation, steam, fuel for process heating, hydrogen, DME, energy supply system in iron works (The total efficiency of the coproduction system unified with the iron works is estimated to increase from the current level by about 14%, and the unit requirement of CO2 emissions is expected to decrease by about 17%.)

96

Part3 Future Outlook Future Outlook for CCT

If we examine the future of Clean Coal Technology from the viewpoint of technical innovation in the coal utilization sector, we

60 LNG steam power generation

Planned gross thermal efficiency (HHV % )

may find a technological trend that is, as mentioned below, crucial for society as well as full of diversity. The trend may be separated into three main directions in terms of key technology development systems.

The first direction is

already seen in two deployment programs now under way which focus on coal gasification technology; one for high-efficiency power generation systems, whose commercialization process is steadily progressing, including "Coal-fired Integrated Gasification Combined Cycle (IGCC)" and "Coal-fired Integrated Gasification Fuel Cell Combined Cycle (IGFC)" and the other for "conversion into liquid fuel and raw material for chemicals" which contains no impurities, such as methanol, DME, or GTL. Moreover, these technologies will give rise to a zero emission-oriented world of

Coal-fired Integrated Gasification Fuel Cell Combined Cycle (IGFC)

LNG-fueled Combined Cycle (ACC)

55

Coal-fired steam power generation Coal-fired Integrated Gasification Combined Cycle (IGCC)

LNG-fueled Gas Turbine Combined Cycle (ACC) (1,700oC-class)

50

45

Coal-fired Integrated Gasification Combined Cycle (IGCC) (1,500oC-class)

40

35 1960

1970

1980

1990

2000

2010

2020

Start of operation year

Fig.1 Change in LNG and Coal Thermal Power Generation Efficiency

"co-production" including co-generation.

Prepared from High-Efficiency Power Generation Technology Review Meeting Report (Jan., 2003) of the Institute of Applied Energy

Gas oil, naphthalene, etc.

IGCC/IGFC

Electric power

Methanol, acetic acid, etc.

Hybrid gasification of coal, biomass, waste plastics, etc.

Boiler Chemicals DME,GTL

Oil

Coal

Power plant, automobiles, etc.

Coproduction manufacturing also raw materials for chemicals

Biomass

Synthesis gas (H2, CO)

Gasification

Commercial, transportation

Coproduction manufacturing also reduced iron

Waste plastics

Reduced iron

Hydrogen station Fuel cell vehicle

H2 production, CO2 separation and recovery

Iron and steel

Gasification furnace

Blast furnace

Stationary fuel cell

Slag

H2

CO2 Effective use Storage Blast furnace

Fig. 2 Various CCT developments centering on coal gasification

100.0

The second direction is future energy sector advancements to cope with the likely realization of "hydrogen energy communities."

Hydrogen economy

According to IIASA 2000 (International Institute for Applied System Analysis 2000), analysis showed that global primary

10.0

energy consumption was on a near-constant increase between Gas: H/C = 4

H/C

the middle of the 1800’s and around 1980 in terms of "H/C unchanged at around H/C = 2 due to an increase in oil

Methane economy

Oil: H/C = 2

(hydrogen/carbon)" ratio. In and after 1980, it remained almost 1.0

Coal: H/C = 1

consumption. As a whole, however, the trend before 1980 is expected to resume, inviting the situation of H/C = 4 around 2030.

In such a society of transition from natural gas to

hydrogen, final energy consumption by carbon combustion will be

0.1 1800

discouraged, even predicting the advent of a situation where coal

1850

1900

1950

2000

2050

2100

Fig. 3 Trend of ratio of hydrogen to carbon (H/C) in the primary energy

energy could be used only in the world of HyPr-RING (Hydrogen

Prepared from IIASA 2000

97

Clean Coal Technologies in Japan

Production by Reaction Integrated Novel Gasification Process,

separate/recover and then sequester/store direct combustion-

where H/C approximates one) and society will be forced to

derived CO2 or reduce CO2 emissions by using carbon

depend largely upon separating and retrieving CO2 generated by

components of coal as fuel or raw material for chemicals by way

the direct combustion of coal and the technology to separate and

of coal gasification and reforming/conversion, presents important

sequester CO2. High-efficiency coal utilization technology to

challenges to Clean Coal Technology.

Separation/recovery

Sequestration/storage

Gas after decarburized CO2 concentration 2%

Separation/recovery Pressure injection from a facility on the sea Pressure injection from a ground facility Tanker transport Separated/recovered CO2 concentration 99%

Discharged CO2 concentration 22%

Cap rock (impervious layer)

Sources from which CO2 is discharged

Dissolution diffusion Pipeline carriage

(including power and steel plants)

CO2

-Chemical absorption method -Physical absorption method -Membrane separation method

Underground aquifer coal bed

Sequestration/storage

Transportation -Ground: Pipeline after liquefied -Sea: (long-haul) Liquefied CO2 transport vessel

Separation/recovery

CO2

-Underground: Aquifer coal bed -Ocean: Dissolution/diffusion or as hydrates (onto the sea bottom)

Fig. 4 CO2 Separation, recovery, isolation, and storage

The third direction is latently potential development of coal

Furthermore, hyper-coal production technology development will

utilization technology in conjunction with each of four technology

lead to processes for the advanced utilization of the carbon within

sectors given priority for development in Japan, namely,

coal.

environmental/energy, bio-, nano-, and information technology

sector is anticipated to lead to such as nano-carbon fibers.

In fact, technological innovation in the nano-technology

sectors. Emphasis is placed on environmental/energy technology development, as mentioned earlier, toward the realization of a zero-emission society mainly through the implementation of "CO2 countermeasures," and the co-production system is regarded as being the target such technical innovation must achieve. Advancements in biotechnology could also unlock methods for

Steel

Chemicals

Other by-products

Cement

the fixation and effective utilization of CO2. Steel-making plant

al ic

es s

m

pr oc

he

C

t an

ok in

g

Light energy

pl

Energy and materials linkage between industries

Fuel (gas/liquid)

C

Raw material

Hydrogen

Fuel cell vehicle

Electric power Iron and steel works IGCC

Chemical energy

IGFC

CO2 recovery

Reformed coal CO2 isolation

Coal

Energy conversion system

Air/water

n/ ss tio ce ac ro ef p qu is Li olys r Py

USC

Joul

Electric&magnetic energy

en tp

Waste, waste plastics Power plant

Coal (solid fuels)

Heat energy

em

SCOPE21

Advanced gasification furnace

Hyper ring

Dynamic energy

la nt

Iron and steel Blast furnace

C

Chemicals, other

Coal partial hydrogenation

Power plant

Hydrogen station

Coal gasification

Gasification/ Conbustion process

Biomass

Environmental facility

USB

Exhaust

Fig. 5 Future energy-oriented society supported by CCT, (2030)

Drainage

Waste heat

Fig.6 co-production system The ultimate goal of a co-production system lies in zero emissions (or the state of purified water and steam discharged )

98

Electricity

Heat (steam/ hot water)

Part3 Future Outlook Future Outlook for CCT

Clean Coal Technologies in Japan

CCT has an important role in the power generation as well as in

energy while environmental preservation is a problem that

the steelmaking sector, where coal functions not only as an

should be tackled on a global scale, considering the

energy source but also as a high-quality reducing agent. A

interdependent relationship between the two. Underlying both,

potential task to be assigned to well-established steelmaking

current population growth is both explosive and unprecedented.

processes (e.g. blast-furnace process) is achievement of an

Efforts toward zero emissions to protect the environment must

innovative level of total coal utilization efficiency, using a co-

be assigned top priority in the development of Clean Coal

production system like DIOS (Direct Iron Ore Smelting reduction

Technologies in Japan. A further obligation, beyond international

process) to simultaneously produce iron and synthetic gas,

cooperation activities, is to continuing development of an efficient

electric power, hydrogen/thermal energy, raw material for

and advanced coal utilization system to minimize impact on the

chemicals, etc. from steam coal for steady implementation of

global environment.

improved environmental measures toward zero emissions.

It has become necessary for us, presently positioned to

As the global leader in coal imports as well as a leader in Clean

undertake technology development in one of the energy-related

Coal Technologies, Japan must remain active in international

sectors given top priority, to further concentrate efforts in an

cooperation mainly in Asia for human resources development,

attempt to devise innovative Clean Coal Technologies for the

technology transfer, and other relevant activities.

establishment of an affluent, clean, and comfortable society

Such

where economic growth is compatible with the environment.

international cooperation may possibly serve not simply those countries dependent upon coal energy for their economic growth but as an important measure to address global environment issues through the extensive influence of the Kyoto Mechanisms, particularly CDM (Clean Development Mechanism). Economic growth indispensably requires a stable supply of

Promotion of innovative CCT development toward the actualization of "Zero-emission" Aiming to position the coal as a source of CO2-free energy by 2030, the project positively promotes the innovative CCT development including the CO2 fixation technology and the next-generation high efficiency gasification technology toward the actualization of "Zero-emission", while identifying the position of individual technologies in the total schedule.

Unification with CO2 separation and fixation technology

Improvement in the thermal efficiency

Coal gasification technology

6 yen/kWh

Air-blow gasification

Zero-emission GFC commercial unit

46-48% sending end efficiency Research and development

55% sending end efficiency

Demonstration test A-IGCC /A-IGFC

Industrial gasification furnace

Advanced coal gasification

Fixation technology

CO2 separation and recovery

>65% sending end efficiency

F/S

Research and development

Research and development

Demonstration test

Research and development

CO2 fixation

6-7 yen/kWh

Demonstration test GCC commercial unit

Oxygen-blow gasification

Actualization of Zero-emission

Demonstration test

Demonstration test of new separation and recovery technology

Development toward the full scale storage

Demonstration test

* Current coal thermal generation unit price is assumed to 5.9 yen/kWh which is estimated by The Federation of Electric Power Companies Japan.

99

Timing of commercialization

(2) Prefix of SI system

(1) Main SI units Quantity Angle Length Area Volume Time Frequency, vibration Mass Density Force Pressure Work, energy Power Thermodynamic temperature Quantity of heat

SI unit rad m m2 m3 s (Second ) Hz (Hertz ) kg kg/m2 N (Newton ) Pa (Pascal ) J (Joule ) W (Watt ) K (Kelvin ) J (Joule )

Unit applicable with SI unit

Prefix

Multiple to the unit

…(degree ), ’(minute), ’’(second)

1018 1015 1012 109 105 103 102 10 10-1 10-2 10-3 10-6 10-9 10-12

(liter) d (day), h (hour), min (minute) t(ton) bar (bar) eV (electron voltage)

Name

Symbol

Exa Peta Tera Giga Mega kilo hecto deca deci centi milli micro nano pico

E P T G M k h da d c m u n p

(4) Coal gasification reactions

(3) Typical conversion factors 1. basic Energy Units 1J (joule )=0.2388cal 1cal (calorie )=4.1868J 1Bti (British )=1.055kJ=0.252kcal 2. standard Energy Units 1toe (tonne of oil equivalent )=42GJ=10,034Mcal 1tce (tonne of coal equivalent )=7000Mcal=29.3GJ 1 barrel=42 US gallons 159l 1m3=35,315 cubic feet=6,2898 barrels 1kWh=3.6MJ 860kcal 1,000scm (standerd cubic meters ) of natural gas=36GJ (Net Heat Value ) 1 tonne of uranium=10,000~16,000toe(Light water reactor, open cycle) 1 tonne of peat=0.2275toe 1 tonne of fuelwood=0.3215toe

(1) 1 2

97.0kcal/mol 29.4kcal/mol

(2) (3)

38.2kcal/mol

(4)

31.4kcal/mol 18.2kcal/mol 10.0kcal/mol

(5) (6) (7)

17.9kcal/mol 49.3kcal/mol

(8) (9)

(5) Standard heating value for each energy source Energy source [Coal] Coal Imported coking coal Coking coal for Coke Coking coal for PCI Imported steam coal Domestic steam coal Imported anthracite Coal product Coke Coke oven gas Blast furnace gas Converter gas [Oil] Crude oil Crude oil NGL, Condensate Oil product LPG Naphtha Gasoline Jet fuel Kerosene Gas oil A-heavy oil C-heavy oil Lubrication oil Other heavy oil product

Unit

Standard heating value

Standard heating value (as kcal)

Old standard heating value

kg kg kg kg kg kg

28.9 29.1 28.2 26.6 22.5 27.2

MJ MJ MJ MJ MJ MJ

6904 6952 6737 6354 5375 6498

kcal kcal kcal kcal kcal kcal

7600 kcal

kg Nm3 Nm3 Nm3

30.1 21.1 3.41 8.41

MJ MJ MJ MJ

7191 5041 815 2009

kcal kcal kcal kcal

7200 4800 800 2000

38.2 MJ 35.3 MJ kg

kg

50.2 34.1 34.6 36.7 36.7 38.2 39.1 41.7 40.2 42.3

9126 kcal 8433 kcal

MJ MJ MJ MJ MJ MJ MJ MJ MJ MJ

11992 8146 8266 8767 8767 9126 9341 9962 9603 10105

kcal kcal kcal kcal kcal kcal kcal kcal kcal kcal

Remark Temporary value

6200 kcal 5800 kcal 6500 kcal kcal kcal kcal kcal

9250 kcal 8100 kcal 12000 8000 8400 8700 8900 9200 9300 9800 9600 10100

old NGL

kcal kcal kcal kcal kcal kcal kcal kcal kcal kcal old Other oil product

Oil coke Refinery gas [Gas] Flammable natural gas Imported natural gas (LNG) Domestic natural gas City gas City gas [Electric power] Generation side Heat supplied to power generator Consumption side Heat produced from electric power [Heat] Consumption side Heat produced from steam

kg Nm3

35.6 MJ 44.9 MJ

8504 kcal 10726 kcal

8500 kcal 9400 kcal

kg Nm3

54.5 MJ 40.9 MJ

13019 kcal 9771 kcal

13000 kcal 9800 kcal

Nm3

41.1 MJ

9818 kcal

10000 kcal

kWh

9.00 MJ

2150 kcal

2250 kcal

kWh

3.60 MJ

860 kcal

860 kcal

kg

2.68 MJ

641 kcal

old LNG old Natural gas

Efficiency 39.98%

100oC, 1 atm Saturated steam

Clean Coal Technologies in Japan

New Energy and Industrial Technology Development Organization (NEDO)

March 15, 2004

Muza Kawasaki Central Tower 16F, 1310, Omiya-cho, Saiwai-ku, Kawasaki-shi, Kanagawa 212-8554 Tel. 044-520-5290 Fax. 044-520-5292

Center for Coal Utilization, Japan (CCUJ) Sumitomogaien Bldg 7F, 24, Daikyocho, Shinjuku-ku, Tokyo 160-0015 Tel. 03-3359-2251 Fax. 03-3359-2280

100

Multi-Purpose Coal Utilization Technology

Environmental Load Reduction Technology Basic Technology for Advanced Coal Utilization

Iron Making and General Industry Technology

Coal Fired Power Generation Technology

Co-production System

New Energy and Industrial Technology Development Organization Muza Kawasaki Central Tower 16F, 1310, Omiya-cho, Saiwai-ku, Kawasaki-shi, Kanagawa 212-8554 TEL.044-520-5290 FAX.044-520-5292 URL: http://www.nedo.go.jp/

Center for Coal Utilization, Japan Sumitomogaien Bldg 7F, 24, Daikyocho, Shinjuku-ku, Tokyo 160-0015 TEL.03-3359-2251 FAX.03-3359-2280 URL: http://www.ccuj.or.jp/