analyzing the problems of preheating system blockage and material heating rate in cement rotary kiln, it is found that preheating system blockage in cement rotary kiln is a common phenomenon, which mainly occurs in the sharp rise of negative pressure above the material blockage position of preheater in cement rotary kiln; There is positive pressure below the blocking part, and the material hole and exhaust valve emit ash outward; The kiln head is not well ventilated, and when it is serious, it will burn out.
The temperature at the inlet of the exhaust fan of the preheater of the cement rotary kiln, the outlet of the primary drum, the outlet of the calciner and the kiln tail rises abnormally, even reaching or exceeding the dangerous temperature range; The ash discharge valve of the preheater is still; The negative pressure of preheater cone decreases sharply or the discharging temperature decreases. If it is not found in time, the cyclone drum will be full of powder in a few minutes, but little material will be discharged into the kiln. When the amount of blocked kiln material is too large, there will be a sudden collapse of the material, and the material powder will rush out of the kiln, causing an accident.
cement rotary kiln preheater calciner and its connecting pipes. There are a lot of crusts in the blockage of connecting pipes of C4 drum and calciner, some of which are hard in texture, and there are a lot of unburned coal particles on the crusts. When high-pressure wind blows, open flames will appear. Four-stage cyclone C4 vertical flue and C4 cone. The plugs of the two are similar, mainly unburned coal particles and raw meal deposits at high temperature; Shrinkage of smoke chamber at kiln end and slope at kiln end. The blockage is mainly crusted material, which is hard after cooling and has high alkali content (R2O). The blockage of C4 cone and discharge pipe of five-stage cyclone is mainly crusted material.
analyzing the influence of the material heating rate in rotary kiln, it is found that the material heating rate has certain influence on minerals. The influence of the heating rate of materials on the formation of clinker minerals, when the heating rate of 611 ~ 811℃/min is adopted, C3S of portland cement clinker minerals can be formed at around 1,311℃, and if the temperature is rapidly raised to 1,451℃, the sintering time of clinker minerals may be shortened, and the sintering temperature is only 1,311℃, and the clinker quality is equivalent to that of new dry kiln. The heating rate of materials has an important influence on clinker production, quality and firing energy consumption.
for the newly-built rotary kiln, the length-diameter ratio is small, and the residence time of materials is shortened by 21min, so as to compress the length and residence time of the transition zone and meet the requirement of increasing the heating rate of the zone. For example, the length-diameter ratio I2 of the new ultra-short kiln, the residence time of the whole kiln material is 21min minutes, and the residence time of the transition zone is only 5-6 minutes, that is, the temperature is quickly raised to 1311℃, which effectively improves the heating rate of the zone and produces excellent clinker quality. The existing three-support kiln with large aspect ratio, small slope and long residence time of materials can increase the kiln speed and shorten the residence time of materials to 1.9-21 minutes, so as to prolong the firing zone and compress the length and residence time of transition zone to meet the requirements of increasing the heating rate of the zone.
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