CHARACTERISTICS AND SYNERGISTIC EFFECTS OF CO-PYROLYSIS OF YINING COAL AND POPLAR SAWDUST

Co-processing of biomass and coal is perceived as a way to enhance the energy utilization by virtue of the integrated and interactive effects between different types of carbonaceous fuels. The purpose of this study was to investigate the co-pyrolysis characteristics of Yining coal and poplar sawdust, and to determine whether there is any synergistic effect in pyrolytic product yields. The coal was blended with sawdust at mass ratios of 9:1, 7:3, 5:5, 3:7 and 1:9. The change of char yields, maximum weight loss rate and the corresponding temperature of different coal/sawdust blends during pyrolysis were compared by thermogravimetric analysis (TG). The total tar yields during pyrolysis of separate coal and sawdust, as well as their blends, were acquired from the low temperature aluminum retort distillation test. From the comparison of experimental and theoretical values of the char yields from TG and tar yields from carbonization test, it was observed that co-pyrolysis of coal/sawdust blends produced less char and tar than the total amount produced by separate coal and sawdust pyrolysis. The different product distribution suggested that there was synergy effect in gas product yields. The co-pyrolysis of demineralized and devolatilized sawdust with coal indicated that the ash in the sawdust was the main contributor to the synergistic effect.