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INTRODUCTION
Refractory industrial rotary kiln is mainly used for calcining lime, magnesia, hard clay, dolomite, bauxite and other raw materials. The main types of fuel are pulverized coal, heavy oil, natural gas, liquefied petroleum gas, etc.
Rotary kiln has the advantages of large production capacity, high degree of mechanization, high product purity, stable quality, and the ability to calcine difficult-to-sinter scraps. Therefore, the waste gas generated by the rotary kiln has high temperature, high dust concentration, large waste gas volume, and high dust specific resistance. Characteristics, the waste gas of the rotary kiln produced by the semi-dry method and the wet method has a large moisture content
Rotary kiln flue gas dust removal parameters
1. Exhaust gas temperature
The temperature of the exhaust gas at the end of the rotary kiln is an important factor affecting the consumption of raw materials. When the kiln type and the calcined material have been determined, the temperature of the exhaust gas from the kiln has a great relationship with the operation of the kiln. If the operation is intensified too much, the heat supply of the kiln will be too much, and the heat cannot be fully utilized, which will increase the temperature of the exhaust gas at the kiln end, resulting in an increase in unit fuel consumption and increase the difficulty of dust removal.
In order to effectively use the exhaust gas to take away heat and reduce the temperature of the exhaust gas, the process should consider waste heat utilization measures. Usually, there are two methods of setting up a heat exchanger and a waste heat boiler to reduce the temperature of the waste gas to below 200 °C after passing through the raw material heat exchanger or waste heat boiler. , it is convenient to take dust removal measures.
2. Dust concentration of exhaust gas
The dust concentration of the exhaust gas at the end of the rotary kiln is very large, generally 20~30g/m (standard), and the maximum can reach 70~80g/m (standard).
The dust concentration of the exhaust gas at the end of the rotary kiln is related to the kiln type, indoor wind speed, raw materials entering the kiln, fuel and other factors.
In the production of rotary kiln, the material and waste gas move in the opposite direction. When the gas flow rate in the kiln increases, the amount of dust carried by the waste gas will inevitably increase significantly. Therefore, changing the flow area of the waste gas will change the dust content of the waste gas; It is beneficial to reduce fly ash losses.
The raw materials entering the kiln will be decomposed when calcined in the kiln. When the proportion of small particle size of the materials in the decomposition zone is large or the powder content in the materials entering the kiln is high, the dust concentration of the exhaust gas is high. Under the same operating system, after the raw materials are screened, washed and other measures, the powder content can be reduced, which can reduce the dust concentration of the exhaust gas.
When using solid dyes, the ash part of the solid fuel is taken away by the exhaust gas, so the dust concentration of the exhaust gas of the pulverized coal rotary kiln is higher than that of the liquid and gas fuels.
3. Exhaust gas volume
The amount of exhaust gas out of the kiln is determined comprehensively by the blast volume of the kiln head and the amount of calcined raw materials selected for the process production.
