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.