Rotary kiln operation method:
1 purpose
Unify the operation idea, realize the balanced and stable production of rotary kiln, further reduce the heat consumption of clinker burning, make full use of low-grade fuel, and ensure the operation cycle of rotary kiln for more than 8 months.
2 scope of use
This procedure is applicable to the central control operation of 4.8× 74mrf5/NC new dry rotary kiln.
3 guiding ideology
3. 1 Ensure the best thermal system, continuously optimize process parameters, and ensure the long-term high-quality, stable, high-yield and low-consumption operation of rotary kiln;
3.2 Establish a global concept, coordinate the raw material system and the coal grinding system, and cooperate closely;
3.3 Three shifts are operated in a unified way, and the wind, coal, material and kiln speed are reasonably matched to ensure the balance of the thermal system;
3.4 Make full use of preheater gas analyzer and kiln exhaust gas analyzer, reasonably match the proportion of coal used in the kiln, and ensure the complete combustion of fuel.
3.5 It is forbidden to enter the high temperature of kiln valve and kiln tail smoke chamber to prevent the cyclone tube of preheater, calciner and kiln tail smoke chamber from crusting and blocking.
3.6 Maintain a reasonable thermal intensity distribution in the rotary kiln, protect the kiln skin and lining, and extend the operation cycle of the kiln system;
3.5 Adjust the grate bed speed and air volume of each room of grate cooler reasonably to improve the heat recovery efficiency.
Process flow of 4 kiln system
4. 1 Raw meal entering the kiln: Raw meal enters the raw meal standard warehouse in Zone 7 through the manual gate valve, electric pneumatic valve and electric flow valve at the bottom of the raw meal warehouse; The raw meal after aeration homogenization is scooped up by manual gate valve, electric pneumatic valve, electric flow valve and chute and sent to the preheater;
4.2 In the RF5/5000 preheater, the raw meal exchanges heat with the hot air flow, and after reaching the C4A and C4B cyclone separators, it enters the decomposing furnace for calcination, then enters the five-stage cyclone separator for material gas separation, and the material enters the kiln for calcination;
4.3 NST- 1 Calciner consists of furnace body and outlet pipe. The tertiary air duct enters the furnace obliquely from one side, and the materials enter the furnace from two outlets. The decomposed materials are collected by a five-stage cyclone separator and then calcined in a kiln.
4.4 The specification of rotary kiln is φ 4.8× 74m; Slope: 4%; Main driving speed: max. 4.0 rpm; Production capacity: 5000 tons/day;
4.5 grate cooler adopts three-stage grate cooler (NC39325), and the stroke adopts hydraulic mode; The actual area of the grate bed is121.2m2. The dust collected at the kiln head is mixed with the clinker from the grate cooler and sent to three clinker warehouses by the plate conveyor. Part of that hot air in the high-temperature section of the cool enters the kiln through the kiln head cov as secondary air, and part of the hot air in the middle-temperature section of the cooler enters the decomposing furnace as tertiary air, and the hot air in the middle-temperature section of the cool enters the coal mill to dry raw coal; The residual gas is discharged into the atmosphere after electrostatic precipitation and dust removal;
4.6 Waste gas treatment: The high-temperature gas of the preheater is pumped by a high-temperature fan, cooled by a humidifying tower, used as a dry heat source of the raw material system or discharged into the atmosphere after electrostatic precipitation at the kiln tail.
5 Preparation before ignition of rotary kiln
5. 1 Technical, mechanical and electrical specialties shall conduct professional inspection and confirmation of the equipment;
5.2 Notify the site to check the preheater system, confirm whether the manhole door and cleaning hole are closed, pitch the ball to confirm that the chute is unobstructed, and lift all flap valves;
5.3 Confirm that the pressure of compressed gas and cooling water is normal;
5.4 Confirm that the oil level of the kiln head diesel tank is greater than 60%;
5.5 Confirm that the DCS system is in normal condition;
5.6 Confirm that the parameters displayed by the central control and regulating system are normal and consistent with the site;
5.7 Confirm the storage of pulverized coal in kiln head. If the pulverized coal is insufficient, notify the coal mill to start the hot blast stove.
5.8 The process technician calibrates the burner coordinates and the ignition point position, and formulates the heating curve according to the process requirements;
5.9 Notify the site to plug in the oil gun to check whether the oil circuit is unblocked, and start the oil pump for oil circulation at the site 1 hour in advance;
5. 10 Start the lubricating station of high temperature fan and the lubricating station of kiln main reducer.
6 ignition temperature rise of rotary kiln
6. 1 Close the cold air baffle of the preheater, the inlet baffle of the high-temperature fan and the fan baffle of the kiln tail system, start the fan of the kiln tail system, and properly open the bypass baffle of the raw meal mill and the fan baffle of the kiln tail system to ensure the slight negative pressure at the kiln head;
6.2 Replace the throttle of the oil gun (￠2.0mm or ￠2.5mm) on site, plug in the oil gun plug and connect the oil pipe of the oil gun;
6.2 fully open the air baffle inside and outside the burner, start the primary fan at the kiln head, and set the speed to 400 rpm; ;
6.3 Fully open the oil return valve, start the diesel pump on site (circulate in advance), and close the oil return valve two minutes before ignition;
6.3 On-site ignition with torches, after the ignition is confirmed, adjust the fuel injection amount, primary air volume and the opening of the internal and external flow baffle of the burner according to the flame shape;
6.4 Contact the raw material system to start the raw material warehousing conveying equipment and start the humidifying tower conveying system;
6.5 When the kiln tail temperature rises to 200 ~ 300℃, add a proper amount of pulverized coal (1t/h) to implement oil-coal mixed combustion. Pay attention to prevent the burner from flameout after adding coal, notify the on-site inspection workers to watch the fire, and communicate with the operators at any time to make adjustments;
6.6 When the outlet temperature of the preheater reaches 50℃, start the emergency fan at the top of the preheater;
6.7 When the kiln tail temperature rises above 350℃ and the preheater outlet temperature exceeds 120℃, close the damper of the main exhaust fan at the kiln head, start the main exhaust fan at the kiln head, and close the damper at the preheater outlet, and keep the negative pressure at the kiln tail at 0 ~-40pa；;
6.8 When the outlet temperature of the preheater rises to 300℃, start the fan of the kiln tail system, and try to control the negative pressure at the outlet of the high-temperature fan to ensure that the high-temperature fan can rotate;
6.9 Strictly control the negative pressure at the kiln head to ensure the complete combustion of pulverized coal and prevent the outlet temperature of the preheater from being too high. When the negative pressure of the kiln head cover is lower than -200Pa, gradually start the air beam fan of the first stage cooler;
6. 10 When the kiln tail temperature is higher than 800℃, the kiln will start to rotate slowly and continuously.
6. 1 1 heating rules for slow rotary kiln:
Kiln end temperature (degree)
100-200
200-300
300-400
400-600
600-700
700-800
≥800
Pan Yao interval
24 hours
8h
4h
1h
30 minutes
15 minutes
Continuous pot kiln
Rotation amount (degree)
120
120
120
120
120
120
Note: In case of heavy rain or strong wind, the kiln should be coiled continuously.
6. 12 When there is too much accumulated material in the first stage of the grate cooler, the central control starts the clinker conveying system, and the first stage grate bed runs at a low speed or intermittently as much as possible to rapidly increase the secondary air temperature;
6. 13 When the kiln tail temperature reaches above 950℃, the feeding operation can be carried out according to the heat storage in the kiln and other conditions are met.
6. 14 When the rotary kiln feeds for two minutes, start the coal feeding system of the calciner and feed the coal to the calciner. Adjust the coal feed according to the temperature in the middle of the calciner, and the temperature in the middle is not allowed to exceed 870℃;
6. When the outlet temperature of15 humidifier reaches about 220+/-20℃, spray water. Select the number of pumps and nozzles before starting the humidifier program. After the outlet temperature of humidifier is stable, switch to automatic water spraying.
7 feeding preparation
7. 1 before feeding 1 hour, throw the ball and put the flap valves at all levels of the preheater;
7.2 When the kiln tail temperature reaches above 800℃, notify the site to start the kiln slow rotation transmission device to carry out continuous slow rotation of the kiln, and notify the lubrication class to add graphite lithium-based grease to the tire belt;
7.3 When the brick replacement in the kiln is more than 5m, and the temperature at the kiln end is more than 650℃, the pre-feeding operation shall be carried out, and the pre-feeding amount shall not exceed 28t;
7.4 Start the clinker conveying system and keep the second and third grate beds running at low speed;
7.5 Notify the laboratory, professional escorts and other relevant departments;
7.6 Start the kiln head electric dust removal ash conveying system;
7.7 When the outlet temperature of kiln head ESP reaches 60℃, notify the site for charging;
7.8 When the outlet temperature of electric dust collection at kiln tail reaches 60℃, notify the site for charging;
7.9 Inform the site to check the discharge ports at the tail and head of the kiln bucket to ensure the smooth flow of materials during feeding;
7. 1 1 Start the dust removal system at the bottom of the homogenizing bin and the circulating aeration system in the bin, set the material level of the standard bin to 120 tons, and start the raw material feeding system, but keep the raw material feeding scale of the standard bin and the outlet pneumatic damper closed;
7. 12 when the tail temperature reaches above 950℃, the feeding operation can be carried out according to the heat storage situation in the kiln and other conditions are met.
8 rotary kiln feed
8. 1 Inform the on-site inspectors to stop the slow rotation of the rotary kiln, disengage the slow rotation clutch, set the kiln speed to 0.4 ~ 0.5 rpm, and start the main motor of the kiln;
8.2 Close the inlet baffle of the high-temperature fan, set the speed to 200rpm, start the main motor, and gradually open the inlet baffle of the fan after the fan runs smoothly, and adjust the fan speed according to the outlet pressure of the preheater. When feeding, the fan speed is controlled at about 450rpm, and the negative pressure at the outlet of the preheater is less than1200 pa; ;
8.3 According to the wind pressure of the kiln head cover, start the fans in the rest rooms of the cooler;
8.4 The first feeding of rotary kiln is120t/h;
8.5 When feeding, the wind, material and coal change greatly. Inform the on-site inspector to shake the flap valves at all levels to ensure the smooth flow of materials during feeding.
8.7 Inform the raw material system to adjust the opening of the fan baffle at the outlet of the electrostatic precipitator to ensure that the negative pressure at the outlet of the main exhaust fan of the kiln is-150 ~-300 Pa. When the outlet temperature of the main exhaust fan of the kiln reaches 200℃+ 10℃, the humidifier sprays water;
8.8 When the clinker enters the cooler, gradually increase the grate speed and the air volume of the grate cooler. At this point, you should:
8.8. 1 Increase the temperature of secondary and tertiary air;
8.8.2 Stabilize the negative pressure of kiln head cover;
8.8.3 Prevent the accumulation of "snowman".
8.9 After the kiln feed is stable, notify the site to stop the diesel pump and draw out the oil gun.
9 Furnace operation
9. 1 When the temperature in the furnace reaches above 450℃, start the primary fan of the TDF furnace burner; When the kiln tail temperature reaches 500℃, start the kiln tail tongue cooling fan;
9.2 When SP kiln runs stably and the outlet temperature of calciner reaches 500℃, it can be put into operation.
9.4 Contact the site to confirm that the pulverized coal conveying system of the calciner is normal, and set the minimum coal feeding amount to start;
9.5 Before feeding coal, add air (adjust grate cooler fan, high temperature fan, tertiary air baffle, internal and external flow ports of burner), adjust the coal feeding amount, and confirm that pulverized coal is completely burned in the furnace;
9.6 When the pulverized coal is on fire and the temperature of the preheater system rises, feed according to the situation;
9.7 According to the thermal working conditions (kiln current) in the kiln and the temperature and pressure of each point of the preheater, gradually increase the kiln speed. And so on, according to this step, gradually increase the kiln feed;
9.8 During the whole furnace charging process, we should pay close attention to the system temperature, pressure, O2, CO content, and the coal supply of the kiln and furnace; In the process of entering the furnace, the coal supply from the kiln head is greater than that from the furnace; After the kiln is fully loaded, the coal supply at the kiln head gradually decreases and the coal supply in the furnace gradually increases. The ratio of the two is W furnace: W kiln = (60 ~ 55%): (40 ~ 45%); In principle, the coal supply to the kiln is determined by the output and quality of the kiln.
Water spraying operation of 10 humidifying tower
10. 1 The dust removal system at the kiln tail is mainly composed of humidifying tower and electrostatic precipitator. The main function of the humidifying tower is to humidify and cool the waste gas at the kiln end, so that the specific resistance of dust is104-101Ω. Cm, so as to improve the dust collection efficiency of electric dust collection. The main function of electrostatic precipitator is to collect the raw meal powder of vertical mill and the dust in the exhaust gas from kiln tail, so that the exhaust gas discharged into the atmosphere can meet the national emission standards.
√ Humidification mode of flue gas: first, spray water from humidification tower; The second is vertical mill and water spraying.
√ There are two ways to adjust the water spray of humidification tower: one is to adjust the number of nozzles; The second is to adjust the opening of the backwater valve on the backwater pipeline.
√ When the vertical mill is running, the outlet temperature of the humidifying tower is controlled at 200-250℃. The main ways of flue gas humidification are to adjust the number of nozzles, stabilize the outlet temperature of humidification tower with the opening of backwater valve, stabilize the outlet temperature of mill with water spray from vertical mill, and finally make reasonable adjustment according to the inlet temperature of electrostatic precipitator.
√ When the vertical mill stops, the flue gas enters the electrostatic precipitation bypass without going through the vertical mill. At this time, the outlet temperature of humidifying tower should be controlled at about 170℃ as far as possible, and the ash hopper should not be wet.
16 18, 1506 When the fan fails to stop, the water spraying of the humidifier tower should be stopped immediately to prevent wet bottom.
1 1 full load operation
1 1. 1 Stabilize the feeding and coal feeding as much as possible, reduce unnecessary adjustments, and even if adjustments are made, they are small adjustments to keep the kiln thermal system stable;
1 1.2 During normal operation, the grate speed should be adjusted according to the grate plate temperature, stratification and grate bed accumulation;
1 1.3 Pay attention to the negative pressure and temperature of the drum at all levels of the preheater to prevent the system from being blocked.
1 1.4 process parameter control value (normal production at full load)
1506 outlet negative pressure: -50 ~ -50~-70Pa kiln tail negative pressure: about -300 Pa.
1506 inlet: CO content < 0. 1% kiln tail temperature:1000 ~1150℃.
The O2 content at the outlet of the primary drum is 3.5 ~ 4.5%, and the apparent decomposition rate of raw materials entering the kiln is more than 90%.
1506 high temperature fan inlet temperature: 200℃ kiln current: 500~800A.
Negative pressure at the outlet of primary tank:-5500 Pa; Kiln barrel temperature: < 380℃
Inlet temperature of humidifying tower: 330℃; Sintering zone temperature: 1350 ~ 1450℃
Negative pressure of kiln head cover: -20 ~-50 Pa
Tertiary air temperature: > 850℃, 1528, pressure under the grate in the first room:
Five-stage drum: outlet temperature 860 ~ 880℃, 4800 ~ 5500 Pa.
Sliding tube temperature 850 ~ 870℃ 1538 inlet temperature: 200 ~ 250℃
Cone negative pressure-1500 Pa
12 kiln shutdown operation
12. 1 Stop the kiln for planned or long-term maintenance.
12. 1. 1 After receiving the notice of the specific kiln shutdown time, estimate the amount of pulverized coal required by the two pulverized coal bins through the back calculation of the specific kiln shutdown time one day in advance.
12.10.2 Determine the stopping time of the coal mill according to the amount of pulverized coal in the pulverized coal bunker.
12.10.3 When the material level in the pulverized coal bin of the calciner is about 15%, the kiln feed will be reduced to 250 ~ 300 t/h, and the kiln will be stopped for preparation.
12.10.4 when the material level of the pulverized coal bunker of the calciner is about 3%, the operator should do a good job of cutting coal at any time and notify the site to knock on the bunker cone and the pulverized coal conveying pipeline.
12.10.5 When the calciner is cut off for scaling, set the coal feed rate of the calciner to 0t/h, close the tertiary air damper, adjust the air volume of the system, and reduce the coal feed rate of the kiln to10 ~130t/h.
During the whole shutdown process, it is necessary to operate gently, and it is forbidden to operate quickly in strong wind to prevent crust and accumulated materials from falling and blocking the preheater.
12.10.6 Before and after stopping the kiln, the raw material quantity of the standard silo should be reasonably controlled according to the pulverized coal quantity of the pulverized coal silo at the kiln head.
12. 1.7 Stop the coal feeding system of the calciner and slow down the kiln speed.
12.65438+
12.10.9 When the materials in the raw meal conveying group equipment entering the kiln are empty, stop the internal discharge of the humidifying tower and switch to the external discharge, and then stop the raw meal entering the kiln conveying group equipment; Start the emergency fan at the top of the preheater to prevent hot air from entering the chute and belt hopper.
12. 1. 10 gradually reduce the amount of coal supplied to the kiln head, reduce the air used in the system and reduce the kiln speed.
12.1.11When the pulverized coal bunker at the kiln head is emptied, after knocking the coal conveying pipe at the hopper cone, notify the repairman to stop the coal supply system and confirm that the kiln emptying stops.
12. 1. 12 Stop charging the electrostatic precipitator at the kiln end.
12. 1. 13 Stop the primary blower of the burner after 4 hours of coal cut at the kiln head (1527).
12. 1. 14 Stop the main motor of the high-temperature fan and start the auxiliary drive.
12. 1. 15 Stop the main drive of the kiln and inform the site to switch to the auxiliary drive. In order to prevent the deformation of the kiln barrel, the kiln should be rotated intermittently during the cooling period.
Rotary kiln standard
1 hour: rotate at the lowest speed or run continuously every 5 minutes (to assist motor operation).
Second hour: rotate every 10 minute.
3rd hour: Turn every 15 minutes.
Hour 4: Turn every 20 minutes.
5-8 hours: turn it every 25 minutes.
The barrel temperature of the firing zone in the kiln reaches about 100℃, that is, it needs to be rotated every 30 minutes before it can be really cooled. When the auxiliary motor is used to rotate the kiln, it rotates 120 degrees every time. On rainy days, the hot kiln needs to run continuously. Grate plate, grate cooler hammer crusher and clinker valve should also be operated.
12. 1. 16 Stop the kiln wheel belt cooling fan and kiln head cooling fan.
12. 1. 17 Before and after stopping the kiln, the air volume of the cooler air chamber and the air volume of the exhaust fan at the kiln head should be reduced accordingly.
12. 1. 18 When there is no "red material" on the grate bed of the grate cooler, stop the cooling fan and stop the transmission system of the grate cooler after the clinker on the grate plate is sent out.
After 12. 1. 19 stops 1538, the electric field of 1537EP stops, and then the electric field vibrates.
12. 1.20 Stop the conveying equipment of 1537.
12. 1.20 When the inlet temperature of the high-temperature fan is lower than 100℃, stop the auxiliary drive and stop the EP exhaust fan at the outlet of the electrostatic precipitator at the kiln tail (16 18).
12. 1.2 1 After stopping the kiln, stop the dilute oil station and the hydraulic block wheel in the kiln, and inform the machinery to support the hydraulic block wheel with a backing plate to prevent the kiln from sliding down.
12. 1.22 After the materials in the ash hopper of the humidifying tower are transported, stop the dust discharge of the humidifying tower.
12.2 temporary kiln shutdown
12.2. 1 Stop feeding, stop the calciner, and appropriately reduce the coal feeding at the kiln head.
12.2.2 reduce the air volume of the system, stop the main exhaust fan of the kiln and switch to the auxiliary drive.
12.2.3 Stop the main motor of the kiln, turn it on slowly, and pan the kiln according to the pan kiln program.
12.2.4 check the preheater and do the pitch test.
12.2.5 Pay attention to system insulation and be ready to feed at any time.
13 trip operation of high temperature fan
13. 1 adjust 1538 baffle and fan baffle in each room of cooler, and control the extraction force of kiln head to -50 ~- 100 Pa to prevent positive pressure of the system.
13.2 discharge dust from humidifying tower, stop feeding coal into kiln and furnace, appropriately reduce coal at kiln head, and notify the site to erect kiln according to regulations.
13.3 notify the preheater for on-site inspection to prevent material collapse and pipe slipping at all levels.
13.4 try to keep the high-temperature fan running at a slow speed.
13.5 pay attention to the collapse of humidifying tower.
13.6 Prepare for heat preservation and feeding.
13.7 notify relevant personnel to find out the cause of the failure and handle it.
A trip operation of 14 cooler
14. 1 Determine the recovery time according to the reason.
Within14.1.1.10 minutes, the following treatments are carried out: reduce the material, kiln speed, coal quantity and system air volume, appropriately increase the opening of fan baffles in each room of the first-stage cooler, and pay attention to maintaining the negative pressure at the kiln head;
14. 1.2 If the shutdown time exceeds 15 minutes, stop the kiln.
15 clinker conveying line fails to stop running and resume running.
15. 1 Determine the recovery time according to the reason.
15. 1. 1.5 minutes, without major operation adjustment;
15.1.25 ~15 minutes, considering the reduction of kiln speed, material reduction, system air volume, etc. Properly reduce the speed of the first and second grate beds, increase the air volume, pay attention to the changes of current and pressure, and avoid the appearance of "snowman" at the front end of the first section;
If 15. 1.3 exceeds 15 minutes, the current and pressure in the first and second sections are too high, and the fault has not been handled properly, the kiln should be stopped;
15.2 resume operation
15.2. 1 After treatment, when starting the clinker conveying group, attention should be paid to the grate speed of the tertiary grate bed to prevent the crusher and conveying line from being overloaded and stopped.
16 run raw meal
16. 1 phenomenon: kiln current drops obviously, nitrogen oxides and O2 concentrations drop, kiln tail temperature drops, grate cooler chamber pressure rises, kiln interior is blurred, and 1537 inlet temperature rises.
16.2 run raw meal treatment
16.2. 1 general situation: appropriately increase coal feed, reduce kiln speed, increase grate cooler speed, and appropriately increase system exhaust.
16.2.2 more serious situation: increase the coal feed rate, reduce the kiln speed, reduce the feed rate, increase the grate cooler speed, and close the tertiary air baffle.
16.2.3 Serious situation: Stop feeding, the kiln speed will be reduced to the minimum, notify the site to watch the fire, if there is no flame in front of the kiln, insert an oil gun for combustion, and then proceed according to the feeding operation after the kiln current no longer has a downward trend.
17 grate cooler fan tripped.
17. 1 A grate bed fan has not stopped. If it cannot be recovered quickly, the kiln should be stopped for treatment;
17.2 one of the second-stage grate bed fans stopped when it could not be quickly recovered, and measures were taken to reduce the feeding, kiln speed and coal quantity, improve the grate bed conveying speed and increase the air volume of other fans, so as to win the emergency repair time.
17.3 one of the three-stage grate bed fans stopped when it could not be quickly recovered, and measures were taken to reduce the feeding, kiln speed and coal quantity, improve the grate bed transmission speed and increase the air volume of other fans, thus winning the emergency repair time.
18 cyclone plugging material
18. 1 phenomenon: the temperature at the bottom of the cyclone decreases, the negative pressure rises sharply, and the outlet temperature of the next cyclone rises sharply.
18.2 treatment: stop kiln and clear materials.
19 power failure operation and recovery
19. 1 system power failure
19. 1. 1 Inform the site that the time interval of slow rotation is slightly shorter than that of empty kiln;
19. 1.2 depending on the recovery time, determine whether to notify the site to pump out the burner;
19. 1.3 Set the values of each regulating group as those during normal shutdown;
19. 1.4 notify relevant equipment (preheater, etc. ) deal with existing problems in time;
19.2 resume operation
19.2. 1 After the electrician sends power, the main and auxiliary equipment can be restored after the site is confirmed to be normal;
19.2.2 Start 1527, and confirm whether to use oil and the heating rate according to the length of kiln shutdown and the temperature in the kiln;
Start all lubricating devices;
19.2.4 start the fan and clinker conveying in the first and second rooms to send away the clinker accumulated in the grate bed as soon as possible;
19.2.5 Other operations shall be carried out in strict accordance with the aforementioned Articles 7, 8 and 9.
20 burner (1526) operation
20. 1 Before the ignition heats up, technicians should check the burner coordinates and the ignition point position, and make records;
20.2 During ignition and heating:
20.2. 1 According to the temperature curve. In the process of heating up, it is necessary to reasonably adjust the oil quantity, the air volume in the burner, the outflow and central flow, and the ventilation in the kiln to obtain an ideal combustion state and avoid incomplete combustion;
20.2.2 In the heating process, if the burner is turned off, it shall be operated according to the above Article 6.5.7;
20.3 During normal production:
20.3. 1 according to the kiln skin condition, clinker quality and system thermal condition, contact technicians to reasonably adjust the burner air, so as to obtain the ideal kiln skin condition and ensure the long-term stable operation of the kiln system;
20.3.2 Always watch the fire, and if it is found that the accumulated material of the burner affects the flame, it shall promptly notify the field personnel to clean it up;
20.4 When the kiln stops abnormally, the burner shall be protected according to the kiln stopping time. If the time is long, refer to 12. 1. 13.
All right. In the recovery process, the operator can control the heating rate according to the actual situation.
Dynamic interpretation operation of 2 1 kiln
The current and power consumption of kiln motor not only provide calcination conditions, but also provide crust conditions. Slight fluctuation indicates that the crust is normal and uniform, while large fluctuation indicates that the crust is uneven or crusted on one side, and the curve on the recording tape narrows or widens accordingly. The transmission current of kiln is a function of kiln speed, feed rate, kiln skin condition, heat in kiln, liquid content in materials and its liquid viscosity, which reflects the comprehensive situation of kiln and is more meaningful than any other parameters. The following are the kiln conditions represented by several driving current variations:
The driving current of 2 1. 1 kiln is very stable, and the described trajectory is very flat. It shows that the kiln system is very stable and the thermal system is also very stable.
2 1.2 kiln drive current traces very thin, indicating that the kiln skin is flat or uneven in the kiln, but the torque exerted on the kiln during the kiln rotation is balanced.
The trajectory drawn by the driving current of 2 1.3 kiln is very rough, which shows that the kiln skin is uneven and the torque generated by the kiln skin changes periodically during the rotation.
The driving current of 2 1.4 kiln suddenly increases, and then gradually decreases, indicating that there is kiln skin or kiln ring collapse in the kiln. The greater the increase, the more the kiln skin or kiln ring collapses. Most caving occurs between the kiln mouth and the firing zone. In this case, the kiln speed should be reduced immediately according to the rising range of the curve (if the kiln driving current rises by about 20%, the kiln speed should be reduced by about 30%), and at the same time, the feeding amount and fuel of the calciner should be reduced appropriately, and further measures should be taken according to the falling speed of the curve. At this point, the cooler should also be adjusted to improve the speed of the grate plate. After the curve turns, the kiln speed, feed rate and calciner fuel are gradually increased to make the kiln turn normally. If this situation is not handled properly, there will be adverse consequences such as raw burning of materials, overload of cooler and damage of grate plate due to excessive temperature.
The high driving current of 2 1.5 kiln can be caused by four situations. First, the kiln is overheated, the firing zone is long, and the materials are carried high in the kiln. If so, reduce the system fuel or increase the feed rate. Secondly, the kiln mouth ring is long and the material filling rate in the kiln is high, which leads to poor granulation of materials and increased ash return of cooler. In this case, the feed rate should be reduced appropriately and measures should be taken to burn the front ring. Thirdly, the granulation performance of materials is poor. Due to various reasons, the clinker is bonded, and the material turns from tumbling to sliding, which makes the kiln difficult to rotate. Fourth, the kiln skin is thick and long. At this time, it is necessary to shorten the flame and shorten the burning zone.
The driving current of 2 1.6 kiln is very low, which may be caused by three situations. First, the kiln is badly burned and close to running raw materials. When it is found that the transmission current is lower than the normal value and has a downward trend in general operation, measures should be taken to prevent further decline. Secondly, there is a back ring in the kiln, and the material accumulates to a certain extent behind the ring, and then rushes into the firing zone through the ring, resulting in short firing zone, fast burning of the material and easy caking. Clinker has many yellow cores and high free calcium. When this happens, the sintering temperature displayed by the instrument is generally high, because there are few fine materials in the sintering zone. In this case, it is necessary to cut down on materials and get rid of the post-cycle. Third, the kiln skin is thin and short. At this time, it is necessary to extend the flame and the burning zone appropriately.
The driving current of 2 1.7 kiln increases gradually, which may be caused by three reasons. First, the kiln is developing towards high temperature. If the original clinker is under-burned, it means that the kiln is becoming normal; If the original burning in the kiln is normal, it means that the kiln is overheating, and measures should be taken to adjust it by adding materials or reducing fuel. Secondly, the kiln began to grow a long kiln mouth ring, the material filling rate gradually increased, and the sticky materials in the firing zone increased continuously. Third, the long and thick kiln skin is forming.
The driving current of 2 1.8 kiln decreases gradually, which is caused by two reasons. First, the kiln is developing towards low temperature. Adding fuel or reducing fuel will produce this result. Secondly, as mentioned above, this situation will also occur when the output increases after the kiln skin or front ring collapses.
There are two reasons why the driving current of 2 1.9 kiln suddenly drops. First, the preheater and calciner system collapsed, and a large number of materials without preheating suddenly poured into the kiln, causing the belt to move forward and burn in front of the kiln. Otherwise, raw materials will be lost. At this time, measures should be taken to reduce the kiln speed and feed rate appropriately and gradually return to normal. Second, large crusts fall on the slope at the end of the kiln, blocking materials, and suddenly entering the kiln in large quantities after accumulating to a certain extent, which has the same influence as the first case. At the same time, large crust also hinders ventilation, poor fuel combustion and low system temperature, which will also make the kiln drive current low.
It is clear, timely and reliable to operate the kiln by relying on the kiln driving current (or torque), and it is more accurate to judge the situation and change in the kiln by combining the parameters such as firing temperature, kiln tail temperature, system negative pressure and waste gas analysis. However, it is impossible to fully and accurately reflect the kiln condition only by relying on any other parameters. For example, the temperature of sintering zone can only reflect the condition of sintering zone, which is easily affected by dust and flame. The kiln current (or torque) can reflect the situation after belt burning in time, predict the situation of belt burning for about half an hour, and prompt the operator to make necessary adjustments. It must be noted that when a normal curve suddenly widens, it means that it has fallen by a large block. At ordinary times, large piles of raw materials are ejected from the kiln mouth, and the whole power consumption is also reduced. In order to block the material again, it is necessary to significantly reduce the kiln speed and increase the fuel quantity accordingly. The falling of large pieces often means that the clinker quantity suddenly increases, and it can't be cooled enough in the grate cooler. Therefore, the downstream of the conveying equipment may suffer from mechanical and thermal overload. This is another reason why the kiln speed and raw material quantity may decrease if this kind of fault occurs. When the kiln operates normally, the output will increase again. Because there is not enough kiln skin, the large fluctuation of kiln skin condition will lead to the damage of lining. So we must pay attention to the uniformity and quality of raw materials. Therefore, for the safe operation of the kiln, it is particularly necessary for the laboratory to carefully monitor the composition of raw materials and clinker.