Study on the correlation between coal property parameters and its pyrolysis heat absorption

Coal properties are important factors affecting the coal pyrolysis heat absorption. In this work, thermogravimetric-differential scanning calorimetry (TG-DSC) method was used to measure the pyrolysis heat absorption of 20 coal samples with different degrees of coalification, including anthracites, bituminous coals, and lignites, to improve understandings about correlation between coal pyrolysis heat absorption and coal property parameters. The pyrolysis heat absorption of coal ranges from 3.2 to 9.1 kJ/g, with the lowest one for lignites and the highest one for bituminous coals. The grey relation analysis was used to identify and assess the correlation degrees between coal pyrolysis heat absorption and coal properties, including proximate analysis, caking index, thickness of colloidal matter layer, vitrinite reflectance, activation energy of pyrolysis reaction. The results showed that the fixed carbon content and activation energy of pyrolysis reaction have the highest correlation degrees with the pyrolysis heat absorption of the studied coals. The activation energy of pyrolysis reaction is linearly positively correlated with the pyrolysis heat absorption of the studied coals. The fixed carbon content and heat absorption are segmented linearly positively correlated, and the segmental point is about 75 % of the fixed carbon content, a correlation equation is provided to estimate the pyrolysis heat absorption of coal based on the fixed carbon content. The comparison between previous studies and present study on the correlation of coal pyrolysis heat absorption and coal property parameter was also discussed.