The air principle of grate cooler in cement kiln
Date：2019-09-27 16:51 Source：cementepcViews:
The operation of grate cooler in cement kiln is to control the thickness of material layer, adjust the cooling air volume to meet the cooling effect of clinker, improve the heat recovery efficiency, maintain a stable and high second or third air temperature, and ensure the dust collection of kiln head and safe operation of conveying system.The operation of the grate cooler is mainly to stabilize the pressure under the grate in one chamber.What are the principles of the grate cooler with the wind, we will understand together.
1. Wind principle of grate cooler
(1) the clinker must be quenched in the first and second Chambers of the grate cooler to the maximum extent and obtain a higher second or third air temperature.However, the volume of air for one or two rooms depends on the volume of two or three times of air consumption, not on the amount of cooling clinker.The amount of second or third wind depends on the amount of air required for coal combustion.
(2) after adjusting the cooling air volume of the first and second chamber, the air volume of the third chamber can be reduced appropriately according to the situation.However, the adjustment of the total air volume of three Chambers should take into account that the clinker can achieve a cooling effect of more than 90% after being cooled in one, two and three Chambers, and the fourth and fifth Chambers should not be subjected to excessive cooling load.
(3) the air volume of room 4 and 5 should be as small as possible to ensure the cooling effect of clinker and the negative pressure of kiln head.
(4) the reduction of fan air output caused by the thickening of material layer should be taken into account in operation.At this point should be appropriate to increase the fan inlet valve opening.
2. Air volume balance of grate cooler
In the grate cooler, the cooling air volume and the second or third air volume, the coal mill air volume and the kiln head fan air volume must reach a balance to ensure the kiln head micro negative pressure.At present, the designed grate cooler has eliminated the movable baffle between the high temperature zone and the low temperature zone. However, under the suction force of kiln head exhaust fan, high temperature fan and coal mill induced draft fan, there is a relative "0" pressure zone in the grate cooler.If increasing the suction force of the kiln head exhaust fan or thickening the material layer causes the air output of the cooling fan in the high-temperature section to decrease, the "0" pressure area will move forward (towards the kiln head), then the air output of the second and third times will decrease, and the negative pressure of the kiln head will increase.Reducing the suction force of the kiln head exhaust fan or thinning the material layer will increase the air volume of the cooling fan in the high temperature section, and the "0" pressure area will move after the meeting, so the air volume will increase when the air temperature drops for the second or third time, and the negative pressure of the kiln head will decrease.Therefore, how to stabilize the "0" pressure zone in operation is very critical to ensure sufficient high temperature of the second or third wind.In the calcination of anthracite, we can find that when the grate cooler material layer is too thick, the negative pressure of kiln head is well controlled and the kiln head is very bright, but the current of kiln is low and f-cao is high.When the grate cooler is thin, the black head is long, but the kiln current is high and f-cao is low.The analysis shows that the grate cooler fan can't supply air when the material layer is too thick, and the kiln head exhaust fan can't supply oxygen and combustion well in the kiln, resulting in low furnace current and high f-cao.When the material layer is thin, although the temperature in the kiln is not high, the combustion of the head coal is good, but the current in the kiln is high and f-cao is low.
The above analysis also shows the importance of controlling the relative stability of the negative pressure of kiln head for stabilizing the second and third air volume.Two - stage grate cooler in operation should pay attention to the two - stage coordination.When the dust collecting temperature of the kiln head will be ultra high if there are too many discharging materials in the kiln, the air volume of the second section fan can be pre-increased, and the grate speed of the second section should be appropriately reduced to ensure good cooling without excessive temperature and overburden of the clinker conveying equipment.When the material layer is thin, the air volume of the second section fan should be reduced to reduce the power consumption.