Influence of Inert Substance on Differential Thermal Analysis of Swelling Coal

The influence of inert substances (alumina, active charcoal, coke, silica gel and quartz powder) on differential thermal analysis (DTA) of swelling coal was studied.Some peaks appeared on the DTA of swelling coal under reduced pressure (3mm /Hg) between 350°C and 550°C, but these were not reproducible, and were considered due to not only thermal change during carbonization but also dilatation of coal. When the swelling of the coal was reduced by mixing with inert substance, only one reprodu-cible endothermic peak appeared between 350°C and 550°C. This endotherm was related mainly to the latent heat of volatile matter. The temperature of endothermic peak was slightly different with kind of inert substance or mixing ratio, and these differences were seemed due to thermal diffusibility of inert substances or samples.The effect of adsorption by alumina, coke or quartz powder on DTA of coal was slight but that of silica gel was remarkably. However, it seemed that the adsorption of imert substances did not affect on the temperature of endothermic peak.