Combustion Properties and Reaction Kinetics of Coal Char Based on Non-isothermal Thermogravimetry

Non-isothermal thermogravimetry was used to study the combustion properties of four kinds of coal char, which were made from Jinkai lignite(JK), Wanshou bituminous coal(WS), Jinzhong Energy anthracite(JZ) and Lidaning anthracite(LDN) under different metamorphic conditions respectively, and their combustion reaction process was simulated by using random pore model(RPM), unreacted shrinking core model and volumetric model. The results show that the combustion properties of prepared coal char are related to metamorphic degree and volatile content of the original coal, and the heating rate. Decreasing the volatile content of coal and increasing the heating rate can lead to faster combustion rate of coal char apparently with shorter combustion time. The kinetic calculation shows that the RPM model is the optimized one to describe the combustion process of coal char, and the apparent activation energy calculated by it for the four kinds of coal char is 55.74, 88.26, 84.27 and 101.30 kJ/mol, respectively.