The process of heat transfer in a coal bed with variation thermophysical properties

New experimental thermodynamically consistent data are presented on the temperature dependence of thermal diffusivity, heat capacity, and thermal conductivity $(\lambda = a\rho C_p)$ of black coal calculated on their basis. The effect of the thermal decomposition (pyrolysis) of coal near $700$ K and evaporation of moisture and other easily volatile components of coal at $380$ K on the behavior of heat capacity and thermal conductivity was studied experimentally. The measurements were carried out using the contact-free laser flash $($Netzsch LFA $457)$ method in the temperature range $301$–$823$ K. Based on the measured values of the thermal diffusivity of black coal, the heat transfer process in a coal bed was studied. It is shown that taking into account the temperature dependence of the thermal diffusivity of the medium when solving the heat transfer equation significantly affects the temperature distribution in the coal bed.