Combustion kinetics of Chinese Shenhua raw coal and its pyrolysis carbocoal

Studies on the structural and thermal characteristics of coal are of great importance for understanding theoretically the process of coal combustion and utilizing the coal resource efficiently, which is a key topic in energy field. In this study, the structural and thermal characteristics of Shenhua raw coal (RC) and its pyrolysis carbocoal (PC) were investigated through particle size distribution, FTIR and thermogravimetric analysis. The effects of heating rates on the kinetic process during thermogravimetric analysis were studied. The combustion processes of the two samples were fitted with nine common kinetic mechanism models. Experimental results showed that the particle sizes became finer after pyrolysis. PC had a higher aromaticity and degree of condensation, but lower 'A' and 'C' factors according to the FTIR analysis. The combustion characteristics indicated that PC possessed better combustion property compared with RC. The first-order reaction model could fit the combustion process of RC and PC well among the nine kinetic mechanism models. With elevating the heating rate, the characteristic reaction temperatures including Ti, Tmax and Tb for RC and PC samples increased, while the values of E and A decreased.