Characteristics and application of co-pyrolysis of coal/biomass blends with solid heat carrier

A series of experiments on co-pyrolysis of subbituminous coal/corn stalk blends with solid heat carrier (boiler ash) were carried out in a bench-scale moving bed pyrolyzer with different biomass blending ratios at different temperatures. Deviation of gaseous, liquid and char products yields between experimental values and calculated ones was discussed. Some characteristics of char and char-ash after co-pyrolysis were investigated, such as elemental analysis, heat value, ash melting point and ash composition. Results indicated that with increasing blending ratio of corn stalk and temperature, both gas and tar yields increased. Gas heat value decreased with increasing corn stalk blending ratio while increased with rising temperature. Compared with coal pyrolysis alone, more light-oil and water were found during the co-pyrolysis process. The char-ash showed little impact on boiler combustion ash at the blending ratio of biomass less than 30%. Application of co-pyrolysis in a poly-generation system was evaluated environmentally and economically.