Non-isothermal and isothermal co-pyrolysis characteristics of coal gangue/coal slime and pine sawdust: Thermogravimetric analyzer and fixed bed pyrolysis reactor study.

The generation and accumulation of coal gangue (CG) and coal slime (CS) are a serious cause of environmental pollution. The co-pyrolysis of CG/CS and pine sawdust (PS) is an effective method to reduce pollution and waste generation. In this work, the co-pyrolysis characteristics of CG/CS and PS were analyzed by the thermogravimetric analyzer and fixed bed pyrolysis reactor. The kinetics analysis showed that the activation energies decreased with the PS mixing ratio increased for CG/PS blends and CS/PS blends in the second pyrolysis stage. The synergistic effect on yield is quantified by comparing the results of the co-pyrolysis of CG/CS and PS blends with weighted results from the pyrolysis of CG, CS and PS individually. The results revealed that when the mixing ratio of CG:PS was 1:1, the difference between the experimental and calculated yields (2.9 %) and the H 2 yield (320 ml/g) were maximum. Among the CS/PS blends, these values are maximum when the mixing ratio of CS:PS is 3:1 (2.5 % and 450 ml/g). Furthermore, the alkali and alkaline earth metals K and Ca in the co-pyrolysis char catalyze the decomposition of the –OH functional group. • CG/CS and PS co-pyrolysis was studied by non-isothermal and isothermal conditions. • The alkali and alkaline earth metals in the co-pyrolysis char had a catalytic effect. • CG/PS1-1 and CS/PS3-1 mixing ratio had the highest hydrogen yield. [ABSTRACT FROM AUTHOR]