Influence of heating rate and particle size on thermo-swelling properties of heating coal

Two bituminous coal samples with particle size less than 212 um were heated at three different heating rates 3, 5 and 10 ⁰C/min under argon atmosphere to investigate the effect of heating rate on swelling, the apparent specific heat and thermal conductivity. Additional studies were undertaken using one sample with a larger particle size of less than 500 um was pyrolysed at a heating rate of 10 ⁰C/min to explore the effect of particle size on swelling and thermal properties. The pyrolytic experiments were conducted using novel Computer Aided Thermal Analysis (CATA) technique. The results indicated that the swelling increased with increasing heating rate and particle size in the temperatures between 400 and 600 ⁰C. The temperature at which rapid swelling commenced during pyrolysis ascended with increasing heating rate but descended with increasing particle size. The apparent specific heat indicated that exothermic heats of reaction, during the primary devolatilization, increased with heating rate and particle size. Thermal conductivities were almost constant prior to the primary devolatilization for all experiments but underwent significant increase during the primary devolatilization depending on the apparent fluidity.