Product Distribution during Co-pyrolysis of Bituminous Coal and Lignocellulosic Biomass Major Components in a Drop-Tube Furnace

Co-pyrolysis of the coal blend with lignocellulosic biomass has a significant influence on final product composition of co-gasification and co-combustion. Successful evaluation of the product distribution during co-pyrolysis is very important to understand the overall co-thermochemical process. In this paper, product distribution, especially the gaseous product evolution during a kind of bituminous coal from northern of China blended with lignocellulosic biomass, major model components (cellulose, hemicellulose, and lignin) were explored in a drop-tube furnace from 600 to 1000 °C. The addition of three model components showed different synergistic effects in the product yields and gaseous product composition. Positive synergistic effects in the gas and tar yields were observed during co-pyrolysis of bituminous coal and cellulose, indicating that the addition of cellulose promoted the formation of volatile products. On the contrary, gas yields from co-pyrolysis of bituminous and lignin mixtures showed a negative synergetic effect. For bituminous and hemicellulose blends, a negative synergetic effect on the gas yield was found, except when the temperature was 600 °C. Whether a positive or negative synergistic effect existed in the composition depended upon the mixing ratio and temperature. Cellulose and hemicellulose showed a similar effect on the gas composition (H2, CH4, CO, and CO2). The addition of cellulose and lignin promoted the proportion of CH4 and light hydrocarbons (C2H4 and C2H6), respectively.