Coal Cryogenic Treatment Temperature Response Model under Multiphase Coupling Effect

The coal is affected by the latent heat of the phase change of in situ and migrating water and the exothermic heat of gas adsorbed by the coal during the freezing process, which leads to different temperatures at different locations and times inside the coal. Relying on the independently developed simulation platform for the freezing response characteristics of gas-containing coal, simulation experiments on the internal temperature change of the coal freezing process under different ambient cryogenic treatment temperatures were carried out, and the effects of the phase change latent heat of the in situ water and migrating water and the exothermic heat of gas adsorbed by the coal on the freezing coal temperature field were taken into account, so as to establish a temperature field model of the cryogenic treatment process of the coal under the influence of the thermal effect of the water and gas and construct the internal heat transfer model of the freezing coal with the aid of COMSOL. The internal heat transfer of frozen coal was constructed with the help of COMSOL, and the mathematical model of temperature field proposed in this paper was simulated and verified. The results show that the change in temperature with time in the coal cryogenic treatment process is consistent with the experimental law. It is generally divided into four stages: rapid decline, short stabilization, slow decline, and relative stability, and the maximum error between the simulation temperature and the experimentally measured temperature is 0.85 K. The rate of temperature decrease of coal during the cryogenic treatment process is accelerated with the decrease of ambient freezing temperature, and the duration of short stabilization of temperature is shortened in the stage of water phase change. The mathematical model proposed in this article can be used to simulate and characterize the temperature field distribution and changes during the cryogenic treatment process of water-containing gas-containing coal.