Process Design Notes

Process Design Notes Kiln Comparison Data 3-Stage SP* 1-Stage SP 2-Stage SP Conversion 4-Stage SP

SF

SF Conversion

Short* L/D Kiln

1.5-2.0

3.0-4.0

3.0-3.5

3.5-4.7

15-18

15-18

15-22

10-12

1.5

1.6

2.8

2.8-3.8

2.1

1.7

1.75

1.9

3.3

3.3-4.5

2.5

3.0-4.0

3.0-4.0

3.0-4.0

4.0

4.0

3.0-4.0

3.5

10-13

10-13

10-13

10-13

10-13

10-13

10-13

10-14

0.20

0.20

0.20

0.20

0.20

0.20

0.20

0.20

0.20

Retention time (min)

150-200

120-160

110-140

95-120

70-85

40-45

20-25

20-30

20-25

Hertz pressure

62,000

62,000

62,000

62,000

62,000

62,000

59,000

59,000

59,000

1300-2000

1150-1450

1050-1150

1000-1100

900-1000

750-860

750-860

750-860

720-780

250-300

550-600

650-700

750-800

900-950

1000-1100

1000-1100

1000-1100

1050-1200

28-35

0.5

0

0

0

0

0

0

0

4-5

4-5

8-10

8-10

8-10

8-10

4-5

4-5

4-5

BZ load (Gcal·h ·m )

5-6

5-6

4.75-5.75

4.5-5.5

4.25-5.25

4-5

2.5-3.5

2.5-3.5

2-3

Stage 1 exit gas T (°C)

---

---

400-425

375-400

375

350

375

375

325-350

Chain section

Yes

Yes

Yes (short)

Yes (short)

No

No

No

No

No

Wet

Long Dry

SF

SF Conversion

Short* L/D Kiln

Capacity (lbm·d-1·ft-3)

28-44

28-44

47-53

56-62

62-81

94-125

187-250

187-218

218-293

L/D (inside brick)

38-44

36-41

30-40

32-34

23-26

15-18

15-18

15-22

10-12

Kiln speed, oper (rpm)

1.2

1.35

1.4

1.4

1.5

1.6

2.8

2.8-3.8

2.1

Kiln speed, max (rpm)

1.4

1.6

1.7

1.7

1.75

1.9

3.3

3.3-4.5

2.5

Slope (%)

3.65

3.65

3.0-4.0

3.0-4.0

3.0-4.0

4.0

4.0

3.0-4.0

3.5

Fill (%)

10-13

10-13

10-13

10-13

10-13

10-13

10-13

10-13

10-14

Ovality (%)

0.20

0.20

0.20

0.20

0.20

0.20

0.20

0.20

0.20

Retention time (min)

150-200

120-160

110-140

95-120

70-85

40-45

20-25

20-30

20-25

Hertz pressure

62,000

62,000

62,000

62,000

62,000

62,000

59,000

59,000

59,000

)

4.7-7.2

4.1-5.2

3.8-4.1

3.6-4.0

3.2-3.6

3.6-4.0

3.6-4.0

3.6-4.0

3.8-4.3

KEG temperature (°F)

500-600

1000-1100

1200-1300

1400-1500

1650-1750

1400-1600

1400-1600

1400-1600

1300-1450

28-35

0.5

0

0

0

0

0

0

0

KEG velocity (ft·min )

800-1000

800-1000

1600-2000

1600-2000

1600-2000

1600-2000

800-1000

800-1000

800-1000

BZ load (MMBtu·h ·ft )

1.84-2.21

1.84-2.21

1.75-2.12

1.66-2.03

1.57-1.94

1.47-1.84

0.92-1.29

0.92-1.29

0.74-1.11

Stage 1 exit gas T (°F)

---

---

750-800

700-750

700

650

700

700

600-650

Chain section

Yes

Yes

Yes (short)

Yes (short)

No

No

No

No

No

Wet

Long Dry

0.45-0.70

0.45-0.75

0.75-0.85

0.9-1.0

1.0-1.3

38-44

36-41

30-40

32-34

23-26

Kiln speed, oper (rpm)

1.2

1.35

1.4

1.4

Kiln speed, max (rpm)

1.4

1.6

1.7

Slope (%)

3.65

3.65

Fill (%)

10-13

Ovality (%)

Capacity (Mg·d-1·m-3) L/D (inside brick)

SHC (kcal·kg

-1 KK

)

KEG temperature (°C) Feed moisture (%) -1

KEG velocity (m·s ) -1

SHC (MMBtu·ton

-2

-1 KK

Feed moisture (%) -1

-1

-2

3-Stage SP* 1-Stage SP 2-Stage SP Conversion 4-Stage SP

1

Process Design Notes

Raw Grinding VRM nozzle ring velocity (AChin-Fatt): 80-90 m/s (w/o external recirc) [15,750-17,700 ft/min] 65 m/s (w/ some material recovery ( 15%)) [12,800 ft/min] 40-45 m/s (w/ external recirc ( 25%)) [7,900-8,850 ft/min] VRM gas flow (Polysius): 1.64 kggas/kgmeal VRM vibration: Frame/reducer mounted sensor: 3 mm/s Housing mounted sensor: 10 mm/s (e.g. Loesche) VRM (w/ dynamic classifier) exit duct grain loading: 620 g/m3 [270 gr/ft3] (LSingh / Polysius) 500-700 g/m3 [225-300 gr/ft3] (AChin-Fatt / Loesche) 500-700 g/m3 [225-300 gr/ft3] (GLabelle / LVT) VRM bed depth: Typical: 3-4” (75-100 mm) Maximum: 5” (125 mm) Approximately 3.5% of table diameter (e.g. Loesche LM36 = 3.6 m × 0.035 = 125 mm) Approximately 6-8% of roll diameter (AChin-Fatt) Power consumption: VRM: 3-12 kWh/ton (=f(material grindability)) BM: 9-17 kWh/ton Typical feed size: VRM: 3-5” BM: 1¼” max to 80% -¾” Typical feed moisture: VRM: > 24% BM: 2-3% w/o drying capability 6-8% w/ drying capability Typical product fineness: 80% -200M (75 ) 0.1% +50M (300 ) Specific surface area of ball charge: 16-20 m2/Mg (AChin-Fatt) Ball charge volume: 24-28% Mill sweep (AChin-Fatt): Not air-swept: 0.8-1.5 m/s Semi air-swept: 2.0-3.5 m/s Fully air-swept: 3.5-6.0 m/s Operating rotational speed (% of critical): 70-72%

2

Process Design Notes

Dew point: Minimum 40°F < dry bulb T Pyroprocess Clinker production increase = f(Q) or f(SP): KK2 = KK1 × (SP2 / SP1)½ KK2 = KK1 × (Q2 / Q1) Specific exit gases flow (=f(SHC, fuel characteristics)): 780-830 kcal/kgKK (2.8-3.0 MMBtu/tonKK): 1.95-2.15 kg/kgKK [1.35-1.50 Nm3/kgKK] 830-890 kcal/kgKK (3.0-3.2 MMBtu/tonKK): 2.10-2.30 kg/kgKK [1.45-1.60 Nm3/kgKK] Kiln exit static pressure: 1.5-2.5 inWG (suction)

LOI sample LOI KF  100  LOI KF 100  LOI sample % Calcination =  100% LOI KF 100  LOI KF Excess air = O2(final) / (20.9 – O2(final)) × 100% False air = (O2(final) – O2(initial)) / (20.9 – O2(final)) × 100% Note: w/ respect to inlet gases False air = (O2(final) – O2(initial)) / (20.9 – O2(initial)) × 100%

Note: w/ respect to outlet gases

ESP operation (combustion / explosion): Set @ 25% of lower flammability limits CH4: 25% of 5% (50,000 ppm) = 12,500 ppm CO: 25% of X% (YYYY ppm) = ZZZZ ppm Hood velocity: 5-8 m/s (FLS) 5-6 m/s (MMcCabe) 4 m/s (KHD) Cyclone p: 1st stage: 5-6 inWG 2nd stage: 8-10 inWG 3rd stage:8-10 inWG 4th stage: 10-12 inWG Bypass: -

Heat penalty (4-stage SP): 5% BP ≈ 1% KF 16,000-22,000 Btu/tonKK per % BP

Volatiles: -

KK S/Alk molar ratio 0.8-1.2 (can be higher as long as sulfur (SO3) comes out in KK) Typical equilibrium time = 150 × kiln retention time [LSingh] Volatilization approx. 15-20 gr/ft3 Chlorides: o < 0.015-0.040% of inputs (raw basis)

3

Process Design Notes

o o o o

< 1.0% of kiln inlet (raw basis) < 0.07% in fuel kiln inlet approx. 50 ×’s inputs precipitate / condense @ 900-1200°F (475-650°C)

Clinker cooler cooling air requirement: Reciprocating grate cooler: 2.8-3.2 kgair/kgKK S-F cross-bar cooler: 2.2 kgair/kgKK (as advertised; realistically 2.5) Secondary (+ tertiary) air mass (=f(1° air, NCA, SHC, EA)): Direct-fired system: 0.9-1.2 kgair/kgKK Indirect-fired system: 1.2-1.5 kgair/kgKK SA / TA proportioned according to fuel split & EA Clinker cooler (grate) loading: Older grate cooler: 30-40 Mg/d/m2 Modern grate cooler: 40-50 Mg/d/m2 Kiln nose cooling fan [HTseng / Polysius]: 725 acfm/ft-Ø SP = 7-8 inWG v = 4,500-5,000 ft/min Manifold v approx 50-60% of nozzle velocity to ensure uniform air distribution Burner tip velocities: Conveying air: 20-50 m/s (80 m/s if single channel burner) Axial air: 80-170 m/s Swirl air: 50-90 m/s Gas: 200 m/s Typical kiln feed densities (Peray p. 178): Preheat zone 75 lb/ft3 (1,200 kg/m3) 10% calcined 73 lb/ft3 (1,170 kg/m3) 20% calcined 70 lb/ft3 (1,120 kg/m3) 40% calcined 65 lb/ft3 (1,040 kg/m3) 80% calcined 60 lb/ft3 (960 kg/m3) Burning zone 92 lb/ft3 (1,475 kg/m3) Estimated kiln feed angle of repose (Peray p. 178): Preheat zone 45° 10% calcined 27° 20% calcined 24° 40% calcined 21° 80% calcined 18° Burning zone 50° Kiln chain unit weight (per Magotteaux): ¾” × 3” Ø: 5.9 lb/ft 7/8” × 3” Ø: 8.6 lb/ft 1” × 3” Ø: 12.52 lb/ft Typical chain system design criteria (LSingh): Chain Zone % kiln length, including bare inlet section Location of curtain from feed zone (Ø)

4

20 – 30 1.0 – 2.0

Process Design Notes

Total chain wt % of daily production (ton/d) ton chains / ton KK Specific surface area (ft2 / ft3 of chain zone) Length of dust curtain chains (ft / ft kiln Ø)

8.0 – 12.0 2.1 to 2.5 2.6 to 3.7 0.66 to +0.77

Kiln chain weight installed (per Duda): Wet process: 120 kgchain/MgKK/d Dry process: 105-110 kgchain/MgKK/d Fuel volatile matter: Decreased VM results in decreased reaction, ergo increased CO (combat via finer grinding & higher temperatures) Typical values: o Coal (bituminous): 25-40% o Coal (anthracitic): 5-15% o Coke (delayed): 8-18% o Coke (fluid): 3.7-7.0% Typical gross heating values and LHV:HHV ratios: Coal: 12,000 Btu/lbm Coke: 14,000 Btu/lbm TDF: 13,700 Btu/lbm (whole tire w/ 13-15% steel) Fuel oil: 138,000 Btu/gal Natural gas: 1,050 Btu/scfm

0.970 0.980 0.960 0.945 0.905

Coal/coke fineness (FLSmidth): Recommended Fineness of Coal/Coke for Kiln and Calciner 30

%R 90  m

25 20

Normal T calciner

15

High T calciner Kiln burner

10 5 0 0

5

10

15

20

25

30

35

40

% Volatiles (ash and m oisture free)

Solid fuel fineness (PAlsop): 0.5% × %VM –200M Coal/coke residual moistures (FLSmidth): Anthracite coal and pet coke: Bituminous coal: Lignite coals:

0.5-1.0% 1.5-2.5% 8-12%

5

45

50

Process Design Notes

Coal mill air:fuel ratio (for drying): Smaller vertical mills: 2.0-2.5 lbair/lbfuel @ 55 HGI 1.0-1.7 lbair/lbfuel @ 100 HGI Larger vertical mills: 1.5 lbair/lbfuel @ 55 HGI 1.0 lbair/lbfuel @ 100 HGI Ball mills: 0.8-1.0 lbair/lbfuel (lower for lighter materials) (HRoser / KVS) Coal mill (VRM) exit duct grain loading: 350-380 g/m3 [150-165 gr/ft3] (AChin-Fatt) Separator (HES) product grain loading: 300-500 g/m3 [125-225 gr/ft3] (GLabelle / LVT) Maximum 600 g/m3 [260 gr/ft3] before see negative impact on separator performance Mill sweep (fuel ball mill): Semi air-swept: 1.0-2.0 m/s (typical 1.5) Fully air-swept: 1.0-2.0 m/s (typical 1.5) [note: CEMEX Brooksville 0.5 m/s] KVS: 2,500-3,000 fpm (13-15 m/s) thru discharge trunnion opening HES rotor peripheral speed: vT = r = r × 2 / t 16-19 m/s (AChin-Fatt) 14 m/s (GLabelle) Ball mill discharge duct exit velocity: 16 m/s minimum (KVS – MGallimore) Microscopy: Heating rate = f(alite size); target = 15-35 m Small = too fast Large = too slow Residence time = f(belite size); target = 25-40 m Small = too short Large = too long Maximum temperature = f(alite birefringence); target > 3.6 Cooling (quenching) rate = f(belite color); target > 3.6 Calcination: Reaction starts ~ 700°C (1,292°F) Reaction fully underway ~ 800°C (1,472°F) Combustibles in kiln feed: Organic (volatile) C ~ 250-350°C (482-662°F) Inorganic (fixed) C ~ 650-900°C (1,202-1,652°F) Secondary firing: 1 s retention time in preheater  20% back end firing VRM grinding pet coke (need to increase friction to increase capacity): Increase dam ring height Add water Increase mill speed

6

Process Design Notes

Finish Grinding (BSA1 / BSA2)n = ton/h2 / ton/h1 = kWh/ton1 / kWh/ton2 n = 1.3 for HES n = 1.6 for 1st gen sep Separator efficiency (bypass): 1st generation: 40-60% 2nd generation: 20-40% 3rd generation: 8-20% Separator (1st generation) clearances: Gap between blade top and drum cover: ⅜-½” Blade extension under drum cover: 1½-2” Separator (HES) feed concentration (Qf/Qa): O-Sepa: 2.5 kg/m3 [1100 gr/ft3] (higher because of distribution table) SEPAX: 2.0 kg/m3 [875 gr/ft3] (lower because fully air-swept) Separator circulating factor, C: C = Rejects (ton/h) / Fines (ton/h) = [fines (x) – feed (x)] / [feed (x) – rejects (x)] CL = Feed (ton/h) / Fines (ton/h) = [fines (x) – rejects (x)] / [feed (x) – rejects (x)] C = CL – 1 Typical C for 1st generation: 200-600% (low end of range for lower Blaine) Typical C for 3rd generation: 100-200% (low end of range for lower Blaine) Separator (HES) exit duct grain loading (to D/C): Slag: 400-500 g/m3 [175-225 gr/ft3] (GLabelle / LVT) Cement: 500-700 g/m3 [225-300 gr/ft3] (GLabelle / LVT) Cement: 0.75 kg/m3 (AChin-Fatt) [325 gr/ft3] Separator (HES) rotational speed (): 20 m/s (for BSA = 3600 cm2/g) O-Sepa  2 rpm/50 cm2/g Tromp Curve (FLSmidth): Cut size: particle size corresponding to the Tromp-value 50% (depends on rotor speed and fineness level; ideally on the steepest part of the curve) Slope (): slope of the curve in the interval 25-75%, e.g. P25/P75 Normal ranges: HES > 0.5 2nd gen 0.3-0.4 1st gen 0.25-0.35 Bypass (): Tromp value at lowest point on curve Normal ranges: HES 5-15% 2nd gen 20-40% 1st gen 30-60% Tromp curve shape affected by: Material load: excessive loading results in increased bypass and lower  value Airflow: insufficient airflow results in higher bypass value and lower  value Circulation factor: increase in circulation factor leads to increase in the bypass value Grinding aid: the use of grinding aid may counteract agglomeration, resulting in reduced bypass value and increased sharpness of separation

7

Process Design Notes

Slot sizes: C1: 6-8 mm C2: 8-10 mm Slot open area: 6-8% of effective area (AChin-Fatt/Fuller) [excluding center screen] 15% of effective area (PAlsop) [including center screen] Material size at division head: 4% +2mm (5% +8M) Material size at mill discharge: 1600-1800 cm2/g (approx half of final product BSA) 5% +30M FM ball charge surface area: C1: 9.5-10.5 m2/Mg (3.0-3.5 lbm/ball) C2: 26-29 (AChin-Fatt) or 28-33 (JBump) or 35-38 (PAlsop) m2/Mg Mono: 18-20 m2/Mg (AChin-Fatt) Power consumption (=f(feed size)): BM: 32-36 kWh/ton (ideal); 34-38 kWh/ton (typical) [1-1½” feed F80] BM: 35-40 kWh/Mg (ideal); 37-42 kWh/Mg (typical) [25-38 mm feed F80] Specific power consumption (LSingh): Mill w/ conventional separator: Mill w/ high efficiency separator: Mill w/ HES and roller press:

1.0 × (BSA/100) = kWh/ton 0.9 × (BSA/100) = kWh/ton 0.75 × (BSA/100) = kWh/ton

Fluorescein mixture: 2 g fluorescein per Mg/h total mill feed 600-800 ml alcohol 2.5 kg mill feed (proportioned for raw KK, gyp and returns) Fluorescein analysis: 100 ml beakers (10-20) 5 g material 50 ml distilled water Grinding aid consumption (8.5 lb/gal): T-I: 0.9-1.1 lbm/toncement T-III: 1.2-1.4 lbm/toncement Typical allowance in tube mill shell length (AChin-Fatt): Feed end liners 75 mm Central diaphragm 500 mm Discharge diaphragm 350 mm Typical shell liner thickness (AChin-Fatt): Lifting (step) liner 95 mm Classifying liner 90 mm Lifting (compt 2) 63 mm DUO-3 (compt 2) 50 mm

8

Process Design Notes

Torque factor in 2nd compt ( in FLS power consumption equations) (AChin-Fatt): Classifying liners 0.65 Lifting liners 0.67 DUO-3 liners 0.66 Ball mill absorbed power design notes (AChin-Fatt): For dry grinding raw mill, add power for the drying compartment For air swept raw mill, increase the calculated power draw by 1.08 For wet grinding raw mill, decrease the calculated power by 0.75 to 0.9 (low for lower % solids) For wet grinding raw mill, use balls no less than 1" in 2nd compt as finer balls tends to float For slag grinding mill, decrease the calculated power draw by 0.95 Typical power losses: Gear & Pinion 3.5% Reducer 1.5% Motor 3.0% Ball volume (%) ≈ 113 – 126 × (H / D) Ball mill operating rotational speed (% of critical): 75-78% Dust Collection Air-to-cloth ratio: Pulse Jet (process D/C): 4.0-4.5 acfm/ft2 Pulse Jet (nuisance D/C): 5.0-6.0 acfm/ft2 R/A: 2.0-2.5 acfm/ft2 “Star” bags: 4.0-4.5 acfm/ft2 Pleated elements: 4.0-4.5 acfm/ft2 D/C can (or thimble) velocity: < 250 ft/min D/C p: Pulse Jet: 3.5-4.5 inWG (bags blinded at 7 inWG) R/A: 2.0-3.0 inWG (bags blinded at 5 inWG) “Star” bags: 4.0-5.0 inWG (bags blinded at 7 inWG) D/C off-time: 8-15 s (higher the better; low off-time contributes to internal bag wear) D/C on-time: 0.10-0.12 s (dependent on “bang”) Blow pipes: Number of holes per pipe  16 Hole Ø:  hole areas  pipe cross-sectional area 1½” Ø pipe (sched 40): I.D. = 1.610”, A = 2.036 in2 1¼” Ø pipe (sched 40): I.D. = 1.380”, A = 1.496 in2 1” Ø pipe (sched 40): I.D. = 1.049”, A = 0.864 in2 ¾” Ø pipe (sched 40): I.D. = 0.824”, A = 0.533 in2 Stagger firing sequence: e.g. 1-4-7-10-2-5-8-11-3-6-9-12-etc. Gravel Bed Filter (GBF): Gas flow per module: 20,000 acfm [LSingh] Based on 128 acfm/ft2 total filter area (comes to 15,000 acfm) [Rexnord] Backflush flow: 8,400 acfm (some specs call for 7800 acfm) [Rexnord, Lurgi] Based on 145-150 acfm/ft2 (flux), 9 ft Ø screen, 2.5-3.0 ft Ø dip tube, 57-59 ft2 screen area Lower: improper cleaning Higher: blow gravel out

9

Process Design Notes

Design p: Gravel bed depth: Rake clearance above screen: Design inlet grain loading:

8-9 inWG (typical is 9-12 inWG) 4.5 in 3/8 in 4-6 gr/ft3

Cyclone dimensioning: d 

where:

4·V 2.6· ·n·3,600

d = nominal cyclone diameter [m] V = total airflow [m3·h-1] n = number of cyclones [---]

Fans Fan power: P [kW] = Q [m3/s] × p [kPa] /  [%] BHP [hp] = Q [cfm] × SP [inWC] / 6356 /  [%] ( = static efficiency) Note: fan p is total pressure difference across fan Fan laws: Density Change Q2 = Q1 p2 = p1 × (2 / 1) P2 = P1 × (2 / 1)

Speed Change Q2 = Q1 × (N2 / N1) p2 = p1 × (N2 / N1)2 P2 = P1 × (N2 / N1)3

Size Change Q2 = Q1 × (D2 / D1)3 p2 = p1 × (D2 / D1)2 P2 = P1 × (D2 / D1)5

Note: valid only for speed changes up to 25% because of assumption that fan efficiency remains constant Tip speed, u: u [fpm] =  × D [ft] × N [rpm] Rule of thumb for calculating fan total pressure w/ straight impeller vanes: 0.6    u 2 p total  g where:

ptotal =  = u = g =

fan total pressure [Pa] gas density [kg·m-3] tip speed [m·s-1] gravitational constant [9.80665 m·s-2]

Wheel inertia: wr2 [lbm·ft2] = W [lbm] × (0.35 × D [ft])2 Round duct equivalent of rectangular duct:

Dr  1.2655

 ab  3 ab

10

Process Design Notes

Environmental Dioxin / Furan formation 450-800°F (230-425°C) Water injection (NOx control): ~ 1 gpm per ton of fuel 10-15% NOx reduction SNCR: Up to 85% NOx reduction 0.40-0.80 USD/tonKK Auxiliary Equipment HEX tube design: 2000-2500 fpm tube velocity (HTseng) Conditioning (spray) tower: air-to-water pressure ratio: > 1.1:1 (empirical @ DEM) air-to-water pressure bias: 10-35 psi (supercedes above note based on LYO & BAL) air rqmt: 95-110 acfm/lance inlet duct: 15° slope (to the vertical) ensure nozzles / spray pattern doesn’t overlap (creates large droplets) soft mist spray desirable, hard spattering spray undesirable Engineering / Miscellaneous Pipe conveying velocities: 3,500-4,000 fpm (18-20 m/s) to transport fine material (raw meal, clinker dust, cement) Pyroline conveying velocities [PAlsop]: Upper limits: Through cooler grate: Kiln hood: Under cooler bull nose: Burning zone (1,450°C): Kiln feed end transition (1,000°C): Preheater riser duct: Preheater gas ducts: Lower limits: Tertiary air duct: Pulverized coal conveying:

5 m/s 6 m/s 15 m/s 9.5 m/s 13 m/s 24 m/s 18 m/s 25 m/s 20 m/s [PAslop]; 16 m/s [GLabelle, Pillard]

Ball mill conveying velocities [Lafarge]: Discharge trunnion: Discharge housing: Discharge duct:

23-25 m/s (max) 4-5 m/s 10-15 m/s

Steel erection: $3.00/lb steel (stiffeners, etc. multiply by 1.25-1.75) [HTseng] Refractory installation: $1.75/lb refractory [MGower] Refractory demolition: $0.44/lb refractory [MGower] Power consumption by P (damper or other): kW = Q (ft3/min) × 0.30483 (ft3 to m3) / 60 (s/min) × P (inWC) × 0.24884 (inWC to kPa) note: Pa = kg·m-1·s-2 and W = kg·m2·s-3

11

Process Design Notes

Motors: If designed for 0.8 PF () and a given hp, can incr  to 1.0 and get more hp as long as stay below FLA kVA = 3 × E × I /1000 kW = 3 × E × I ×  /1000  = kW / kVA = cos ( = phase angle) Transfer point dust collection vent line sizing: Assume 1 ft3 per 1 ft/min belt speed (???) e.g. 24” belt = 24” × 6” (height of air above belt) = 2’ × ½’ = 1 ft2 × 1000 ft/min = 1000 cfm Hardness scales: Solid fuels: Hardgrove grindability index (HGI) – lower value represents harder to grind material Minerals: Mohs scale (1 = talc, 10 = diamond) Metals and alloys (penetration tests): Brinell hardness number (HBN)  Rockwell hardness test (Rc) [note: scales A, B, C, D, E, F, G)  higher value = harder Also: Vickers, Meyer, Meyer-Vickers, Knoop  Kiln nose ring cooling air flow (HTseng / Polysius): Total air flow requirement = 725 acfm/ft-Økiln [Duda approx 20% higher] Nozzle velocity = 4,500-5,000 ft/min Fan SP = 6.5-8.0 inWG Manifold velocity approx 50-60% nozzle velocity Kiln shell/tire thermal gradient (T between the two): Typical (floating tire): 180°C Modern (splined/fixed tire): 360°C Calculation of shaft diameters (Polysius):

N M d  71,620   n where:

d 3 where:

Md = torque [cm·kg] N = power [hp] n = rotational speed [rpm]

Md 0.2 K d d = shaft diameter [cm] Kd = torsional stress [kg·cm-2] Wrought iron Mild steel Forged steel Cast iron

120 200-400 300-480 160-320

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