Experimental study on hydrogen-rich gas production by co-gasification of coal and biomass in a fluidized bed

The hydrogen-rich gas production by co-gasification of coal and biomass was studied in a bench-scale fluidized bed and the effects of Equivalence Ratio (ER), steam/carbon ratio (Fs/Fc), biomass/coal ratio and biomass type were examined in the temperature range of 850℃~1050℃. The results show that the concentration of carbon dioxide and gas yield increase with the rise of ER, while the concentrations of carbon monoxide, hydrogen and methane decrease. With the increase of Fs/Fc weight ratio, the concentrations of carbon dioxide and methane increase, while those of carbon monoxide and hydrogen decrease, and the gas yield decreases following a slight increase. The concentration of carbon dioxide, hydrogen and methane increases with the increase of biomass/coal ratio, but that of carbon monoxide decreases, and the gas yield increases at first and then decreases. Coal and biomass blend can be co-gasified with as high as 50% of biomass. Among the three types of biomass used, coal/sorghum stalk gasification has the highest hydrogen concentration, and the order of gas yield for various fuels is as follows: coal/pine sawdust>coal/sorghum stalk>coal/rice straw>coal. In this experiment, the maximum volume content of hydrogen in gas and hydrogen yield can reach 37.25% and 0.54m³/kg, respectively.