DETERMINATION OF CALORIFIC VALUES OF COALS BY DIFFERENTIAL THERMAL-ANALYSIS

This paper examines a further use for the thermal analysis technique in the coal science field. Eight Spanish coal samples, of different origin and rank, and their corresponding chars have been studied. The applicability of differential thermal analysis (DTA) for determining the calorific values of coals has been tested after analysing its suitability to estimate the enthalpy of the C-O2 reaction. The correlation of the enthalpy values obtained from coals and chars to those accepted in the literature is satisfactory. The calorific values, obtained by DTA, of these eight coal samples have been compared to those obtained by the ASTM method and those calculated from a semiempirical equation. There is a high level of correspondence from that comparison which proves that DTA could also be highly applicable for determining the calorific values of coals when an adiabatic bomb calorimeter is not available or when the amount of representative sample is too small to allow its use.