Temperature control in the coal powder preparation process!
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Why is the temperature in the coal powder preparation process controlled at 90–120°C? If the temperature is too low, the coal powder will have a high moisture content; what are the consequences of too high a temperature?
The original poster’s description is a bit vague; the temperature for preparing pulverized coal should be controlled between 90 and 120°C. This refers to the pipeline system for pulverized coal coming out of the coal mill, while the hot air entering the coal mill should be about 100°C higher than this temperature. The outlet temperature of the mill is controlled between 90 and 120; if the temperature is too low, water vapor condensation will cause the pulverized coal to aggregate and clump together, affecting its transportation. At excessively high temperatures, pulverized coal begins to undergo dry distillation, releasing volatiles. For coal types with a high moisture content, the temperature must not be too low; otherwise, there will be problems with transportation.
Why is the temperature in the coal powder preparation process controlled at 90–120°C? If the temperature is too low, the coal powder will have a high moisture content; if it is too high, the coal will coking
This post was last edited by Zhuzhang Mangxue on 2015-9-8 09:41. Coal dust drying requires a certain degree of superheat; otherwise, water vapor tends to condense during storage and transportation. However, the superheat level cannot be too high, as the filter bags in bag filters cannot withstand extremely high temperatures (usually <150°C). Under normal operating conditions, the dew point temperature is around 60°C; if it is higher, the dilution fan needs to be turned on.
Temperature control of the coal grinding system: The typical target temperature at the outlet of the coal grinder is 105°C; the usual set values for the low interlock threshold are 90°C, while the high interlock thresholds are 115°C and 120°C. Exit after 115 seconds of delay, exit immediately at 120 seconds. Effects of low temperature: The coal grinding system operates under negative pressure, with a negative pressure at the outlet of the coal grinder of around -3.5 KPa and a water content of approximately 24–25%. Under these conditions, the saturated steam temperature corresponding to the steam partial pressure is around 95°C. Too low a temperature will cause water vapor to condense, leading to scarring on the filter bags of bag filters and blocking their pores, thereby reducing their service life. When the temperature is too high, it can cause the membrane (or coating) on the surface of the bag filter cartridges to melt and peel off under such high temperatures; therefore, the temperature must not exceed 120 degrees.