Causes and Control Measures of Rotary Kiln Ring in Active Lime
Posttime£º2017-10-20 13:53:51 Read£º729
1 rotary kiln ringing symptoms
Rotary kiln ring system after the system the following symptoms: kiln main motor load increases, the current fluctuation value increases, kiln head, kiln pressure instability, positive phenomenon of kiln head, kiln air turbidity, kiln material affected by dust Its movement from the rolling state into a sliding state, the cylinder skin local temperature drop.
Kiln check kiln ring state:
Kiln total of three lanes (February 25, 2010 as an example): the first, the cylinder from the kiln to 24m at the junction of 1m long, thick 400mm full circle; the second, the cylinder From the kiln to 28.5m knot 0.5m long, thick 200mm full circle; third, the cylinder from the kiln to 37.5m knot 0.5m long, thick 200mm intermittent circle.
2 rotary kiln ring damage
Rotary kiln knot once formed, it hindered the smooth air flow, kiln head positive pressure phenomenon, most of the kiln high temperature airflow was blocked in front of the knot body, so that the kiln air flow can not be evenly distributed, Material can not fully absorb the heat, the material within the kiln by the dust of its movement by the rolling state into a sliding state, the material can not be uniformly heated, the material can not guarantee the quality of calcination, knot once the formation of 200mm ~ 300mm, the main motor current at any time by Large, serious easily lead to equipment failure, while increasing energy consumption, serious damage to the scene environment, increase the operator labor intensity.
Analysis on the Reason of Rotary Kiln
3.1 raw materials containing impurities and more easily lead to rotary kiln ring
As the main raw material of lime raw material is CaCO3, generally contain SiO2, Al2O3, Fe2O3, NaO, K2O, P, S and other impurities, if the impurity content is high, it is easy to produce knot, especially Al2O3, Fe2O3, S and so its melting point is low, in the rotary kiln temperature of 1 250 ¡æ or more will produce melting, melting impurities, with the rotary kiln rotation attached to the rotary kiln calcination belt at the highest formation of knot ring.
3.2 high temperature so that dust can easily cause melting ring
Kiln before the storage field due to rain-free facilities in case of rain and snow weather, the surface of the material stained on the surface of the ore can not afford to wear, with the ore together into the kiln calcined, lime in a large number of dust into the kiln, through the calcining zone, high temperature so that dust Easy to cause knot.
3.3 improper choice of burner directly affect the rotary kiln ring
The burner is the main process equipment for calcining lime, which directly affects the flame shape and stiffness, which directly affects the calcination temperature of the rotary kiln. Different fuels should use different burners to make the fuel fully combusted, the choice and control of the burner Vital, but also a direct impact on the kiln ring.
3.4 Rotary kiln speed and pause time match improperly affect the knot
Rotation kiln speed and the expected time to match the material in the kiln thick thickness of the material thickness of the material in the kiln movement trajectory. The kiln speed is low, the material is short to form the material layer is too thick, the material appears in the kiln drop phenomenon, the material layer is thin, it will form the material in the kiln as a whole slide, throw and slide will produce material powder, Large, in the calcined belt by a strong flame of high temperature, it will melt to form a ring.
3.5 production operation control improper impact knot
1) Rotary kiln preheater outlet temperature is too high, the material in the preheater preheat and decomposition accelerated, will be sintered in the calcined, lime over burning, easy to cause knot ring.
2) kiln tail pressure control size, will change the flame length, shape, a direct impact on changes in the kiln and lime quality, easy to produce knot.
3) in the fuel flow under normal circumstances, the gas pressure control is too low, burning flame short rough, calcined belt to provide too much heat to make the material burned, serious calcined belt knot.
4) the rational distribution of a second wind directly affect the calcination and quality of stability, a wind is too large, the flame will be short, high temperature is too concentrated, causing knot ring; the other hand, long flame, calcination temperature is low, will make the quality of lime Stable, easy to ring.
4 control measures
4.1 strict raw materials into the factory acceptance system
First, to strengthen the physical test control, into the plant size should be controlled at 25 ~ 45mm, reduce the incorporation of small particles of raw materials, to avoid a lot of ash into the kiln. The second is to strengthen the laboratory test control, the plant into the raw materials for rigorous testing, control CaO content of not less than 53%, MgO, SiO2 content control in 2.0% and 1.0%, S content of less than 0.015%, nonconforming raw materials Into the kiln.
4.2 reduce the kiln into the kiln raw material powder rate
In order to solve the problem of knotting, limestone mine in 2009 before the ore into the warehouse to increase mobile screening equipment, the No. 3 belt head shaker screen from the original woven mesh to punch, but the case of rain and snow weather Clogging, cleaning process affect the production, should further improve the sieve structure, so that into the kiln powder rate control within 5%.
4.3 control the kiln speed and the expected time to match
Material from the kiln to the kiln to complete the limestone decomposition of the whole process, and the preheater to the rotary kiln puffing volume must be synchronized with the rotary kiln speed, that is, a certain yield must be developed to the corresponding rotary kiln speed To ensure that the material in the rotary kiln material thickness and filling volume. The normal control of the material in the kiln filling rate of 6% to 8%, the kiln speed to achieve the material particles self-roll is appropriate.
4.4 reasonable control of the Ministry of thermal parameters
According to the improved burner, adjust the burner angle, reasonable control kiln tail fan pressure, flow and the first and second fan air volume and wind pressure, in order to ensure the flame length and stiffness, so that the flame and the cylinder to maintain parallel; Gas plant in a timely manner to communicate, requiring the provision of calorific value, pressure are stable gas supply, including calorific value ¡Ý 15 048kJ / m3, the pressure between 9 800 ~ 11 000kPa, according to Table 1 reasonable control of the Ministry of thermal parameters to ensure that the kiln Steady condition.
4.5 to strengthen the calcination process management
1) at any time to observe the kiln flame, air, material movement, if found flame shape divergence, kiln air turbidity or material sliding phenomenon, should immediately check the physical quality of the product SiO2 is high, while reducing production and cooling, adjust the kiln. Choose high-quality raw materials into the kiln, to be physical quality improved, the kiln air flow smoothly, the dust was significantly reduced, and then gradually yield, return to normal production, to avoid the melt to stick to the wall.
2) every hour in the kiln from the grid side door to take a sample, with the naked eye analysis of physical quality, according to physical quality, adjust the gas and other process parameters.
3) cooler under the vibration of the feeder evenly ash to ensure that the cooler within the high, low expected bit difference in the 100mm or so, so that the secondary air supply evenly.
4) plan to cut production, should be 50t / h gradient gradually cut production, while timely adjustment of gas and other parts of the process parameters; restore production, according to the temperature curve to operate (rotary kiln heating curve shown in Figure 2).
4.6 The following measures should be taken in the event of a knot
1) from time to time short cut, stop kiln, at the same time, stop one or two fans, observe the kiln lining situation, if a slight knot ring, choose the appropriate time to cut, cool, use high and low temperature difference to break off, deterioration.
2) If there is kiln head, kiln tail to produce positive pressure, kiln air turbidity, the main motor current increases, can not complete the normal production, quality and other phenomena, need to stop kiln treatment.
5 Conclusion
Active lime rotary kiln ring lime industry is a common problem, knot factors are also many aspects, both raw materials, fuel effects, but also with the choice of burner and production process control, etc., as long as the strengthening of all aspects of management, prevention for The main rotary kiln ring can be effectively controlled, and then continue to extend the cycle cycle, and gradually realize the rotary kiln high yield, stable production.
Rotary kiln ring system after the system the following symptoms: kiln main motor load increases, the current fluctuation value increases, kiln head, kiln pressure instability, positive phenomenon of kiln head, kiln air turbidity, kiln material affected by dust Its movement from the rolling state into a sliding state, the cylinder skin local temperature drop.
Kiln check kiln ring state:
Kiln total of three lanes (February 25, 2010 as an example): the first, the cylinder from the kiln to 24m at the junction of 1m long, thick 400mm full circle; the second, the cylinder From the kiln to 28.5m knot 0.5m long, thick 200mm full circle; third, the cylinder from the kiln to 37.5m knot 0.5m long, thick 200mm intermittent circle.
2 rotary kiln ring damage
Rotary kiln knot once formed, it hindered the smooth air flow, kiln head positive pressure phenomenon, most of the kiln high temperature airflow was blocked in front of the knot body, so that the kiln air flow can not be evenly distributed, Material can not fully absorb the heat, the material within the kiln by the dust of its movement by the rolling state into a sliding state, the material can not be uniformly heated, the material can not guarantee the quality of calcination, knot once the formation of 200mm ~ 300mm, the main motor current at any time by Large, serious easily lead to equipment failure, while increasing energy consumption, serious damage to the scene environment, increase the operator labor intensity.
Analysis on the Reason of Rotary Kiln
3.1 raw materials containing impurities and more easily lead to rotary kiln ring
As the main raw material of lime raw material is CaCO3, generally contain SiO2, Al2O3, Fe2O3, NaO, K2O, P, S and other impurities, if the impurity content is high, it is easy to produce knot, especially Al2O3, Fe2O3, S and so its melting point is low, in the rotary kiln temperature of 1 250 ¡æ or more will produce melting, melting impurities, with the rotary kiln rotation attached to the rotary kiln calcination belt at the highest formation of knot ring.
3.2 high temperature so that dust can easily cause melting ring
Kiln before the storage field due to rain-free facilities in case of rain and snow weather, the surface of the material stained on the surface of the ore can not afford to wear, with the ore together into the kiln calcined, lime in a large number of dust into the kiln, through the calcining zone, high temperature so that dust Easy to cause knot.
3.3 improper choice of burner directly affect the rotary kiln ring
The burner is the main process equipment for calcining lime, which directly affects the flame shape and stiffness, which directly affects the calcination temperature of the rotary kiln. Different fuels should use different burners to make the fuel fully combusted, the choice and control of the burner Vital, but also a direct impact on the kiln ring.
3.4 Rotary kiln speed and pause time match improperly affect the knot
Rotation kiln speed and the expected time to match the material in the kiln thick thickness of the material thickness of the material in the kiln movement trajectory. The kiln speed is low, the material is short to form the material layer is too thick, the material appears in the kiln drop phenomenon, the material layer is thin, it will form the material in the kiln as a whole slide, throw and slide will produce material powder, Large, in the calcined belt by a strong flame of high temperature, it will melt to form a ring.
3.5 production operation control improper impact knot
1) Rotary kiln preheater outlet temperature is too high, the material in the preheater preheat and decomposition accelerated, will be sintered in the calcined, lime over burning, easy to cause knot ring.
2) kiln tail pressure control size, will change the flame length, shape, a direct impact on changes in the kiln and lime quality, easy to produce knot.
3) in the fuel flow under normal circumstances, the gas pressure control is too low, burning flame short rough, calcined belt to provide too much heat to make the material burned, serious calcined belt knot.
4) the rational distribution of a second wind directly affect the calcination and quality of stability, a wind is too large, the flame will be short, high temperature is too concentrated, causing knot ring; the other hand, long flame, calcination temperature is low, will make the quality of lime Stable, easy to ring.
4 control measures
4.1 strict raw materials into the factory acceptance system
First, to strengthen the physical test control, into the plant size should be controlled at 25 ~ 45mm, reduce the incorporation of small particles of raw materials, to avoid a lot of ash into the kiln. The second is to strengthen the laboratory test control, the plant into the raw materials for rigorous testing, control CaO content of not less than 53%, MgO, SiO2 content control in 2.0% and 1.0%, S content of less than 0.015%, nonconforming raw materials Into the kiln.
4.2 reduce the kiln into the kiln raw material powder rate
In order to solve the problem of knotting, limestone mine in 2009 before the ore into the warehouse to increase mobile screening equipment, the No. 3 belt head shaker screen from the original woven mesh to punch, but the case of rain and snow weather Clogging, cleaning process affect the production, should further improve the sieve structure, so that into the kiln powder rate control within 5%.
4.3 control the kiln speed and the expected time to match
Material from the kiln to the kiln to complete the limestone decomposition of the whole process, and the preheater to the rotary kiln puffing volume must be synchronized with the rotary kiln speed, that is, a certain yield must be developed to the corresponding rotary kiln speed To ensure that the material in the rotary kiln material thickness and filling volume. The normal control of the material in the kiln filling rate of 6% to 8%, the kiln speed to achieve the material particles self-roll is appropriate.
4.4 reasonable control of the Ministry of thermal parameters
According to the improved burner, adjust the burner angle, reasonable control kiln tail fan pressure, flow and the first and second fan air volume and wind pressure, in order to ensure the flame length and stiffness, so that the flame and the cylinder to maintain parallel; Gas plant in a timely manner to communicate, requiring the provision of calorific value, pressure are stable gas supply, including calorific value ¡Ý 15 048kJ / m3, the pressure between 9 800 ~ 11 000kPa, according to Table 1 reasonable control of the Ministry of thermal parameters to ensure that the kiln Steady condition.
4.5 to strengthen the calcination process management
1) at any time to observe the kiln flame, air, material movement, if found flame shape divergence, kiln air turbidity or material sliding phenomenon, should immediately check the physical quality of the product SiO2 is high, while reducing production and cooling, adjust the kiln. Choose high-quality raw materials into the kiln, to be physical quality improved, the kiln air flow smoothly, the dust was significantly reduced, and then gradually yield, return to normal production, to avoid the melt to stick to the wall.
2) every hour in the kiln from the grid side door to take a sample, with the naked eye analysis of physical quality, according to physical quality, adjust the gas and other process parameters.
3) cooler under the vibration of the feeder evenly ash to ensure that the cooler within the high, low expected bit difference in the 100mm or so, so that the secondary air supply evenly.
4) plan to cut production, should be 50t / h gradient gradually cut production, while timely adjustment of gas and other parts of the process parameters; restore production, according to the temperature curve to operate (rotary kiln heating curve shown in Figure 2).
4.6 The following measures should be taken in the event of a knot
1) from time to time short cut, stop kiln, at the same time, stop one or two fans, observe the kiln lining situation, if a slight knot ring, choose the appropriate time to cut, cool, use high and low temperature difference to break off, deterioration.
2) If there is kiln head, kiln tail to produce positive pressure, kiln air turbidity, the main motor current increases, can not complete the normal production, quality and other phenomena, need to stop kiln treatment.
5 Conclusion
Active lime rotary kiln ring lime industry is a common problem, knot factors are also many aspects, both raw materials, fuel effects, but also with the choice of burner and production process control, etc., as long as the strengthening of all aspects of management, prevention for The main rotary kiln ring can be effectively controlled, and then continue to extend the cycle cycle, and gradually realize the rotary kiln high yield, stable production.
