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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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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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SilzR
13 Jun 2008
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
