Influence of fundamental internal parameters to low-temperature critical temperature in coal self-ignition process

Résumé

Low-temperature oxidation process of coal self-ignition can be divided into two stages-slow oxidation stage and fast oxidation stage. To study the effect of internal factors to low-temperature critical temperature in coal self-ignition process, 8 fundamental internal parameters (volatile, ash, fixed carbon ,C, N, S, H and O) and 3  characterization parameters of low-temperature critical temperature in coal self-ignition process (T_JR,T_CO and T_O2) were determined on theoretical analysis first, then the self-heating characteristics in pure oxygen atmosphere in the range from 40 to 180℃ and gas releasing atmosphere in the range from 30 to 180℃ for 7 coal samples were tested. Based on this, the values of fundamental internal parameters and characterization parameters for 7 coal samples were obtained. The relationship between fundamental internal parameters and that of characterization parameters were compared. On grey relational analysis, 5 important influence parameters are filtered to make mathematical formula fitting with characterization parameters. The result shows that characterization parameters reflect critical temperature from different aspects-temperature rising, CO releasing and oxygen consumption. They are different for the same coal sample, but are with the same tropism and confirm each other. Critical temperatures is negatively correlated with the contents of volatiles, H and O, not of determined relationship with the content of S and having small correlation with other parameters.