Coal And Biomass Pyrolysis Process Of Thermogravimetric Analysis

Thermogravimetric analysis (TGA) method was used to investigate the influences of heating rate, particle size, mixing ratio, catalyst concentration on pyrolysis characteristics of nine kinds of biomass, three sorts of coals and the mixture of both under N2atmosphere respectively.The whole process of biomass pyrolysis could be divided into three stages, dehydration, devolatilization and carbonation. Devolatilization was the main process which occurred approximately between200～30℃. While the pyrolysis process of coals could centrally divided into dehydration and degassing stage, depolymerization and decomposition stage which was the primary process and occurred between400～50℃and the second degassing stage. The pyrolysis kinetics of both biomass and coals could be analysed as first order reaction. The peak weight loss rate Wmax,the peak temperature Tmax and the activation energy E of both biomass and coals exhibited linear increment by1.31～3.71mg/min,29.9～64.9℃,3.03-14.58kJ/mol respectively along with the increasing of heating rate. And Wmax、Tmax、E of both biomass and coals also exhibited linear increment by0.312～1.655mg/min,2.20～29.1℃,2.45～21.77kJ/mol along with the increasing of particle size. There was a kinetic compensation effect between E and the pre-exponential factor A.Co-pyrolysis of biomass and lignite/bituminous coal seemed to exist synergistic effects on each other for the disappearing or decreasing of the original peak of lignite/bituminous coal and the appearing of the new peak.The synergies of co-pyrolysis of biomass and anthracite were not obvious:the pyrolysis process of anthracite could be affected by the cellulosic biomass, existing a significant temperature hysteresis, while at the role of lignocellulosic biomass, anthracite pyrolysis peak remarkably reduced.Co-pyrolysis of cellulosic biomass and lignite/bituminous catalyzed by Na2CO3 /K2CO3with high alkalinity indicated more remarkable catalysis. E and Tmax reduced3.28～6.49KJ/mol and19.5～61.1℃respectively with a catalyst content of8%, and Wmax increased0.211～1.607mg/min when the dosage of catalyst was0.5%.The weight loss of cellulosic biomass-lignite blends increased6.1%～11.83%with K2CO3and KOH catalysts content of0.5%, but the weight loss reduced with the increasing of KCl, K2CO3and KOH contents in the cellulosic biomass-bituminous coal blends.