Effects of intrinsic properties, particle size, bulk density, and specific gravity on thermal properties of coal...

Thermal properties of pulverized coal govern the heat transfer and greatly influence the coal dust explosion and spontaneous combustion processes. This study measures the thermal properties of five coal samples at six distinct particle sizes using an advanced thermal property analyzer. The thermo-physical properties of coal dust positively correlated with the particle size. Thermal conductivity, diffusivity, and specific heat capacity increased with the ash percentage, bulk density, and specific gravity of coal dust. In contrast, they negatively correlated with the fixed carbon and volatile content of coal. Empirical relations between the thermo-physical properties were developed. The thermal conductivity, diffusivity, and specific heat capacity of coal dusts varied in the range of 0.091-0.147 W/mK, 0.125-0.164 mm²/s, and 0.715-0.945 MJ/m³K, respectively. With increase in particle size from < 38 to 500-1000 µm, thermal conductivity, thermal diffusivity, and specific heat capacity increased in the range of 25.60-32.89%, 9.76-22.11%, and 9.57-20.80%, respectively, for different coal samples.