Will the volatiles in lignite be lost at a drying temperature of 105–110°C?
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This post was last edited by jordan569 on 2013-1-6 at 21:47. It was found that during the drying of lignite, its calorific value is lower when dried at 105–110°C compared to when dried at 80°C; I wonder if this is due to some of the volatiles in the lignite evaporating . Note # ) # # , .
No, generally, bituminous coal begins to release volatiles only at temperatures above 300°C.
This is the temperature value used to measure the total moisture content in coal; volatiles do not appear in these readings. Based on the results from several experiments, bituminous coal begins to release volatiles intermittently at temperatures above 240 degrees
If the calorific value of LZ refers to the high calorific value, it is easy to explain. Since water has been removed at 105–110°C, the high calorific value decreases.
The volatile components are not lost at this temperature. If drum drying is used, due to the large number of functional groups on the surface of lignite and its high content of reactive hydrogen, partial oxidation occurs at this temperature; as the drying time increases, the mass of the lignite increases. I have conducted this experiment. A temperature of 270°C is required for a small amount of volatile substances to be removed; trace amounts of CO2 can be detected in the dried gas, which is mainly due to decarboxylation reactions. Hydroxyl groups begin to be removed at temperatures above 300°C ； A small amount of the fatty side chains are also removed, and CH4 can be detected in the gas. The data mentioned are the results of experiments on Shenhua Baori lignite; there are indeed differences among lignites from different locations!
If testing the moisture content of lignite, the temperature should be 105–110°C; a forced-air drying oven is used, and nitrogen shielding is required!