Abstract:

Non-caking coal was often used as gasification and power generation coal, and the heat generation was low due to the coal formation stage, and the heating rate had a greater influence on the heat release of coal-oxygen composite at different stages. The heat release process of Non-caking coal at different heating rates (10, 20, 30, 40 ℃/min) up to 1 000 ℃ was tested by synchronous thermal analyzer, and the changes of heat release and ignition heat in the coal-oxygen composite process were analyzed. The apparent activation energy was solved by the Starink method, and the effect of apparent activation energy on the heat release was clarified. The coal-oxygen composite stage with the greatest influence of heating rate was analyzed by the gray correlation method. The gray correlation method was used to analyze the coal-oxygen composite stage that was most affected by the heating rate. The results show that the heat flow changes of Non-caking coal can be divided into five stages: evaporation heat absorption, oxidation exothermic, decomposition heat storage, combustion exothermic and combustion exhaustion. With the increase of heating rate, the heat flow density gradually shifts to the high temperature area and the energy redistribution phenomenon occurs, and the heat release per unit mass of Non-caking coal increases by 19.2%. The percentage of exothermic heat in the exothermic stage of combustion increases from 70.6% to 75.1%, and the heat of ignition is 360~380 J/g. The apparent activation energy decreases gradually from 0 to 0.90, and increased abruptly at 0.95, with a peak value of 143.44 kJ/mol. The exothermic stage of combustion and exhaustion stage were most affected by the warming rate, and the evaporation and heat absorption stage was least affected by the warming rate.

Key words: non-caking coal, rate of warming, coal-oxygen complex, heat release, apparent activation energy