Study on thermal effects and gases derivation of spontaneous combustion of gas-containing coal.

• Gas action inhibits initial coal oxidation, but promotes pyrolysis and combustion. • Significant differences in the effect of particle size on oxidation and pyrolysis. • The mechanism of gas transport on the process of coal spontaneous combustion was analyzed. • Gas has a stage-specific effect on the derivation of oxidized gas from the coal body. Heat release and gas derivation can reflect the degree of coal spontaneous combustion (CSC) as important indicators. Meanwhile, both physical and chemical properties of gas-containing coal and methane molecules are important factors for CSC. The C600 high-precision microcalorimeter was coupled with a gas chromatograph to conduct oxidation and pyrolysis experiments on gas-containing coal. The thermal effects and gas derivation rules in the process were analyzed. The influence of the physicochemical properties of gas-containing coal on the spontaneous combustion process was clarified. The quantitative relationship between particle size and heat release coal was discussed. The experimental results show that compared with raw coal, the unique characteristics of gas-containing coal are as follows: (1) The oxidation process is slowed down, while high temperature combustion is more adequate, and pyrolysis is more likely to occur and more intense; (2) The heat absorption and release intensity increased to different degrees, and the characteristic temperature shifted forward; (3) With the decrease of oxygen consumption and generation of CO 2 , CO release increases significantly; (4) As the particle size of gas-containing coal decreases, the oxidation is more likely to occur, while pyrolysis is slowed down. The research results provide an important theoretical basis for the prevention and control of spontaneous combustion of gas-containing coal. [ABSTRACT FROM AUTHOR]