Experiment Study on Gas Indexes Optimization for Coal Spontaneous Combustion Prediction

An experiment study was conducted on the gas indexes for coal spontaneous combustion prediction in Maodi Mine with the programmed temperature ris e experiment of coal spontaneous combustion. With the gas components and concentration obtained at each stage of the coal oxidation pyrolysis process, the data obt ained from the experiments were treated and analyzed with the Grignard fire disaster coefficient, alkane ratio and other methods. According to the optimization principle of gas indexes, the CO concentration, second fire disaster coefficient R 2 and alkane ratioφ( C 2 H 6)/φ( CH 4) were selected as the main gas indexes to adjust coal spontaneous combustion in Maodi Mine. With the CH 4 concentration, C 2 H 4 concentration, C 2 H 6 concentration, the first fire disaster coefficient R 1 and the third fir e disaster coefficient R 3 and alkene alkane ratio as the auxiliary gas indexes, the spontaneous combustion critical temperature range of the coal samples from Maodi Mine was 60 ~ 70 °C and dry cracking temperature was 110 ~ 130 °C were obtained. This method would have certain guide function to effectively adjust the firing stage and degree of the coal spontaneous combustion, as well as to predict and forecast the spontaneous combustion of the seam.