煤和生物质共气化制备富氢气体的实验研究

在煤处理量为8kg/h的小型流化床反应器上,以富氧空气和水蒸气为气化介质,对煤和生物质共气化制取富氢燃气进行了实验研究。在850℃～1 050℃主要考察了空气当量比、水碳比、生物质比例和生物质种类对燃气组成和气体产率的影响。结果表明,对煤和稻草混合体系,稻草质量比为33%时,空气当量比增加,CO2含量显著增加,H2、CO和CH4含量减少,气体产率增加;水碳比增加,CO2和CH4含量增加,CO和H2含量减小,气体产率先增加后减小;生物质比例增加,CO2、H2和CH4含量增加,CO含量降低,气体产率先增加后减小,当生物质比例小于50%时,可以实现体系的稳定运行。对于三种不同的煤与生物质混合体系,煤与高粱秆共气化所得煤气中H2含量最高,气体产率的顺序为:煤/木屑煤/高粱秆煤/稻草煤。实验中H2在煤气中的体积分数最高可达37.25%,最大产率为0.54m3/kg。

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.