Pyrolysis Behavior of Macerals from Weakly Reductive Coals

Pyrolysis of the vitrinites and inertinites separated from three weakly reductive coals (WRCs) and one reductive coal were carried out by thermogravimetry coupled with mass spectrometry (TG-MS) and in a fixed-bed reactor to investigate the effects of the reductive degree on the pyrolysis behavior of macerals. TG/differential thermogravimetry (DTG) analyses showed that the vitrinites and inertinites from three WRCs have lower weight loss and weigh loss rate but higher peak temperature than those from Pingshuo (PS) coal. The pyrolysis process of the macerals can be described by three-step independent first-order kinetics models, and the macerals from three WRCs have lower average activation energy than those from PS coal. The differences in the evolution profiles of H-2, CH4, C2H6, and CO2 between the macerals from three WRCs and from PS coal were also characterized using TO MS. The results of coal pyrolysis in the fixed-bed reactor showed that the vitrinites and inertinites from three WRCs have lower tar yield but higher gas yield than those from PS coal and the chars from the macerals of three WRCs have higher combustion reactivity than those from PS coal.