KilnLine Operation

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Operation of the kiln line Training Klaus Grittner Polysius Services Polysius Headquarters / Germany 19. May – 13. June 2008

Training THALOFA

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Operation of the Kiln Line Heating Up Starting Sequence Start Up Increasing Performance Normal Operation Optimisation Main Control Loops Normal Shut Down Emergency Power Consumers

Training THALOFA

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Clinker Production Line 80 °C

Pre heater Calciner

340 °C; to raw mill and / or EP

fuel

900 °C Tertiary Air Duct

55 – 60 %

860 °C

fuel

1700 °C Rotary kiln

280 °C; to EP

40 – 45 %

350 °C 1400 °C Clinker cooler 80 - 100 °C Ambient air temp.

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Heating up the kiln line • The fuel burns with the smallest possible amount of combustion air. • There is no CO, or only slightly formation of CO at the kiln inlet • Most of the heat remains in the clinkering zone • The flame is short and compact. • for the new kiln heating up takes approx. -- 48 hrs. (with new brick lining) -- 30 – 36 hrs. (after normal maintenance shut down)

Training THALOFA

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Example for 1st heating up the kiln line

or heavy fuel oil

Continuous turning

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Tilting and turning the kiln During the heating up the kiln should be continuously inched and turned, the guide values for a new kiln are : 0 – 12 h:

1/3 revolution with auxiliary drive

every 30 minutes

12- 24 h:

1/3 revolution with auxiliary drive

every 20 minutes

24 – 36 h:

1/3 revolution with auxiliary drive

every 15 minutes

36 – 46 h:

1/3 revolution with auxiliary drive

every 10 minutes

46 - 46 h:

continuous rotation with auxiliary drive

 0,1 rpm

from 48 h:

turn kiln with main drive

app. 0,6 rpm and start feed

Training THALOFA

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Starting-up Sequence of the Kiln Line Remarks: Auxiliaries of the kiln line

De-dusting plant

Control air compressors, cooling water system. rapping system

Filter dust transport De-dusting filter fan

Kiln waste gas fan (ID-fan)

with closed damper

with closed damper

Training THALOFA

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Starting-up Sequence of the Kiln Line Remarks: Primary air fan for MB

Fuel supply (fuel oil or coal)

With damper closed

CO < min. - analyser behind cyclone 2 - analyser before bag house

Clinker transport

Cooler waste air filter dust transport

„Bull Nose“ cooling fan

cooler roof protection

Training THALOFA

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Starting-up Sequence of the Kiln Line Remarks: Cooling for roller crusher

Roller crusher Cooling air fans for recuperation zone

Cooler exhaust air fan

Cooler de-dusting filter

With damper closed

With damper closed

Training THALOFA

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Starting-up Sequence of the Kiln Line Remarks:

Main burner

many preconditions (CO, T….)

Cooler grates

Kiln main drive

Cooling fans for kiln shell

Cooling fans for kiln outlet

slow speed  0.6 rpm

only if main drive is running

Training THALOFA

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Starting-up Sequence of the Kiln Line Remarks: Kiln feed

Cooling tower

Pre-heater cleaning systems

Open tertiary air dampers

Calciner burners

app. 20 %

Fuel MIN

Training THALOFA

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Start of the Kiln Line / Kiln Feed

!

For kiln feed start sufficient personnel has to be in the pre-heater to watch the function of the pendulum flaps and material flow!!!

1. Cooler Grates:

~ 3 - 5 stroke/min, (minimum speed)

2. Kiln main drive :

0,6 – 0,8 rpm

3. Cooler Fans :

~ 30% of the nominal quantity kiln hood pressure: -1 to -2 mm WG (Automatic control)

4. Main burner fuel:

Heavy oil: Coal / Pet coke:

5. Start Kiln Feed :

~30 to 35% of nominal feed rate (new kiln, no coating) att.: there is a time delay between kiln feed group start and real kiln feed.

6. Adjust draft after : cyclone pre-heater

- 12 to -15 mbar by ID-fan/ dampers exhaust gas duct.

~1.000 Nm³/h ~ 6.000 kg/h

Training THALOFA

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Start of the Kiln Line / Kiln Feed 7. Main burner :

Increasing of the fuel quantity to specific heat consumption  1300 ...1500 kcal/kg clinker Att. ! : It’s only a guide value!!!

8. Start PC-burner :

Sufficient Oxygen

Fuel distribution: Kiln inlet : After stage I: Hot meal 1:

- after cyclone stage 2: > 2,5 % - after DOPOL: > 4,0 % MB ~70-75%, PC ~25-30%. ~ 1050 °C, ~ 860 °C, ~ 840 °C

9. Adjustment of cooling air:

according to kiln feed ( ~ 2,0 Nm³/kg clinker)!!!

10. Observing clinker formation:

visual check, kiln camera, pyrometer, observe the power consumption of the kiln drive.

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Gas analyser / Alarm set points

Gas analyser behind Calciner -- CO (max-max. 0,8 %; calciner burner) -- O2 normal value app. 2,5 %

CO > 0.6 % alarm CO > 0.8 % shut off the calciner burners CO > 1,1 % stop the main burner

Gas analyser before bag house -- CO (max-max 1,1 %; main burner) -- O2 normal value app. 4,0 %

Gas analyser behind kiln -- CO (max 0,8 %, Alarm) -- O2 (min 1,0 %, Alarm)

Training THALOFA

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Increasing the kiln performance Precondition: granulated clinker in the sintering zone and in the clinker cooler 1.

Increasing the gas flow through the cyclone pre-heater

via damper or speed of ID-fan- / filter-fan Oxygen content behind cyclone stage 5 > 4,0 % before increasing fuel. After ID-fan: keep -50 mm WG (by EP-fan)

2.

Stepwise opening of the tertiary flaps

(Oxygen at kiln inlet adjust to ~2 – 3 %)

3.

Increasing of clinker cooler air quantity

keep kiln hood pressure -1 to -2 mm WG. (control loop)

Training THALOFA

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Increasing performance 4.

increase of kiln feed and fuel

target of fuel distribution: -- MB ~ 45%, -- PC ~ 55%

5.

increase of kiln speed

according to the kiln feed

6.

close fresh air flap (if open)

depends on temp. after the pre-heater

7.

operate clinker cooler with

-- until a clinker bed dept ~ 500 mm

slow speed

-- pressure in aeration chamber 1 ~ 40 mbar)

Same above mentioned steps for further increasing of the kiln feed!

Training THALOFA

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Increasing performance Cooler grate velocity

(watch the pressure!!!) and cooling air quantities have to be adapted (1,8 …2 Nm³/kg Clinker)!

Att.: Secondary air and tertiary air temperatures will rise! The specific heat consumption will reduce!!! Prevent overheating the sintering zone!!! Take attention to:

the kiln inlet temperature (max. 1150°C), the hot meal temperature (max 870°C), the temperature after pre-heater (normal 340°C, max. 450°C):

Training THALOFA

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Normal Operation Preconditions of trouble-free operation: - most homogeneous raw meal (LSF, SR, AR) - constant kiln feed (variation < 1 % / minute) - constant fuel rates (variation < 1 % / minute) - constant gas flows, cooling air flows

Training THALOFA

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Optimisation of the plant

-- Process parameters -- Typical operating parameters -- Burner-/ Flame adjustments

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Process Parameters 1.

kiln feed rate

tons / h

2.

Specific heat consumption,

kcal / kg

3.

Total fuel rate ,

tons / h

4.

Proportion of fuel to pre calciner / riser,

%

5.

Secondary air temperature ,

degree C

6.

ID fan draft ,

mbar

7.

Pre-heater exhaust gas temperature,

degree C

8.

Kiln inlet gas analyser

O2 %, CO %, NOx mg

9.

Cyclone stage II gas analyser

O2 %, CO %, NOx mg

10. After ID.-fan gas analyser

(calculated)

O2 %, CO %, NOx mg

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Process Parameters 11.

Water into the cooling tower

l/h

12. Kiln feed material (meal chute 1)

SO3 %, LoI. %, (Lab. results)

13. Kiln drive power ,

kW, Amps

14. Primary air pressure

mbar

15. Clinker cooler ventilators, air volume

Nm3 / h

16. (Primary air,

Nm3 / h)

17. Pre-heater profile (Temp. Pressure)

°C; mbar;

18. Specific Calculations

kcal/kg clinker

-- Specific kiln volume loading,

tons / m³day

-- Gas velocity in burning zone,

m / sec

-- Specific heat loading of burning zone,

Mcal / h per m2

Training THALOFA

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Typical Operation Parameters Temp.:

Press.:

Clinker cooler:

-- gas duct 1:

860….... 880 °C

-- meal chute 1:

840….... 860 °C

-- tertiary air:

850….... 950 °C

-- after pre heater:

320….... 340 °C

-- Kiln Hood:

- 0,1……- 0,3 mbar

-- Kiln Inlet:

- 4…. ….- 6 mbar

-- Gas Duct 1:

-14…….- 16 mbar

-- after Pre heater:

- 50…….- 60 mbar

-- Chamber 1 pressure

50…..…. 60 mbar

-- Secondary air temp.

900….... 1000 °C

-- Cooler exhaust air temp.

250….... 300 °C

-- Clinker temperature

80……... 100 °C

Training THALOFA

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Burner- / Flame Adjustment

-- to burn a good clinker quality, but prevent damages in the refractory. -- to build and to keep good coating formation. as protection of kiln bricks and reduced kiln shell temperature, but also to avoid coatings rings etc. -- good heat transfer to the material by radiation and convection.

Training THALOFA

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Burner- / Flame Adjustment Main Burner Fuel:

-

Total Fuel:

- Specific heat consumption (kcal/kg clinker) - Temperatures of meal and gas in the pre-heater

Fuel Calcinator:

- Hot meal temperature - Degree of calcination (92...95%)

Attention:

Temperature of sintering zone Kiln inlet temperature Kiln main drive power (A or kW) Free lime (CaO) in the clinker

Orientation only! Parameters/Results may overlap!!!

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Training THALOFA

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Optimal Operation: Gas conditions:

CO ---> to be prevented!!! min. of Oxygen is required!

Oxygen after pre-heater:

~4%

by damper or fan speed

Oxygen after stage II

~2–3%

by damper or fan speed

Kiln inlet:

~ 1,5 - 2 %

by Tertiary Air Flaps

-- more open: Oxygen stage II up / kiln inlet down!!! -- more closed: Oxygen stage II down / kiln inlet up!!!

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S:\Team\Training\THALOFA\CD-for-Customer\05-04-KilnLine-Operation.ppt

Main control loops of a kiln plant Kiln hood pressure

Target: Actuator:

 -0.1 mbar Cooler exhaust fan speed or damper

Under grate press. (chamber 1 or 2)

Target: Actuator

constant at set point hydraulic drive for grates

Cooler air flow

Target: Actuator:

constant at set point Cooler fan speed or damper position

Press. after kiln ID fan

Target: Actuator:

 - 5 mbar EP-fan speed or damper position

Temp. after Cooling tower

Target: Actuator:

 160-190 °C Water valve at the return line

Training THALOFA

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Normal shut-down of the kiln plant Generally -- reducing of the kiln feed in steps of app. 5% -- minimal kiln feed is about 40…50% -- an empty kiln can be easier heated-up and re-started! •

Stop of PC-Burners and kiln feed

•

Reduce fuel at the main burner

•

Reduce pre-heater draft

•

Close the Tertiary air sliders / flaps

•

Stop of main burner primary fans to be kept in operation (for cooling!!!)

•

Close the DOPOL-flaps to 10-15%

Training THALOFA

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Normal shut-down of the kiln plant •

DOPOL-fan:

dampers to be closed

•

Clinker cooler fans: dampers to be closed

•

Cooler exhaust air fan: controlled by kiln hood pressure measurement, or set to minimum value

•

Kiln to be tilted! - during cooling down - if raining continuously with auxiliary drive - 1st and 2nd hour each 10 min 120° - 3rd hour each 15 min 120° - 4th hour each 20 min 120° - 5th till 8th hour each 25 min 120° - then... each 30 min 120° ...till a kiln shell temperature (sintering zone) of about 100°C is reached

•

cooler track units:

to be operated in intervals

Training THALOFA

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Emergency power consumers -- Emergency lighting -- Communication systems -- UPS unit for computer and process automation equipment -- Control voltage for the total kiln plant -- Cooling water supply system -- Dampers in DOPOL exhaust gas duct -- Kiln auxiliary drive including lubrication) -- Oil pumps for circulation lubrication system for roller bearings -- Primary air fans for all burners including actuators -- Protective air fan for sintering zone pyrometer -- Actuators for damper in tertiary air duct -- Fan for kiln outlet cooling -- Cooling air fans for roller crusher -- Cooling air fans for recuperation section

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Training THALOFA

Rotary Kiln Main Plant Interlock

Temperature Preheater > Max Max

STOP

FILTER FAN STOP

CO Preheater > Max Max

KILN ID-FAN

PRIMARY AIR FAN

STOP

STOP

Stop Timer 0,5 hour

KILN FEED STOP

STOP

Temperature Preheater > Max Max

STOP

MAIN BURNER

STOP

CALCINER BURNER

Filter dust transport

STOP

Stop Timer

CO Stage 2 > Max Max CLINKER Transport STOP

MAIN DRIVE

5 min

Grate 2

Grate 1

Stop Timer 5 min

STOP

CLINKER COOLER failure of 2 or more air fans

CLINKER COOLER

CLINKER COOLER Exhaust air fan

failure of one fan

Stop Timer 15 min

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Training THALOFA