催化热解生物质制取富氢气体的研究

在实验室自制的固定床反应器上, 考察了秸秆和锯屑的热解行为, 研究了热解产物分布特别是富氢气体的体积分数和产率, 着重研究了（5种金属氧化物和2种碳酸盐催化剂）的催化效果。结果表明,温度从500 ℃提高到850 ℃, 秸秆和锯屑的热解气产率分别从29.0%提高到40.6%, 35.0％提高到46.5%, 而对应的富氢气体的体积分数分别从41.2％提高到48.2%, 40.6％提高到47.0%；在5种金属氧化物中，Cr2O3显示了最好的催化效果，在750 ℃时对应的热解气产率与不使用催化剂相比提高了10％，富氢气体的体积分数提高了13％；催化剂（CaCO3和Na2CO3）占生物质的质量分数对热解气和富氢气体产率有明显的影响，当质量分数从0增加到30％时， 热解气和富氢气体产率增加较明显，而后其值的增加可以忽略， 因此推荐使用的催化剂质量分数为30％。

Production of hydrogen-rich gas from biomass by catalytic pyrolysis

Aimed at producing hydrogen-rich gas, pyrolysis of rice straw and sawdust was carried out in a fixed-bed reactor at different temperatures with catalyst (Cr2O3, MnO, FeO, Al2O3, CaO, CuO and Na2CO3). The results show that at current operating conditions, total gas yield and hydrogen-rich gas yield are low. However, it could be improved by using catalysts. The addition of Cr2O3 at 750 ℃ leads to the increase of the total gas yield by 10% and the concentration of hydrogen-rich gas by 13%. High temperature favours the yield of total gas and the concentration of hydrogen-rich gas. When the temperature rises from 500 ℃ to 850 ℃, the yield of total gas and the concentration of hydrogen-rich gas, for rice straw pyrolysis, increase from 29.0% to 40.6%, and 41.2% to 48.2%, respectively; for sawdust pyrolysis from 35.0% to 46.5%, and 40.6% to 47.0%, respectively. The catalysts used exert positive effect on pyrolysis of rice straw and sawdust, however, Cr2O3 appears stronger catalytic role than other metal oxides. 30% catalysts (CaCO3, Na2CO3) is recommended because higher amount of catalyst almost does not improve catalytic activity again. The addition of CaCO3 or Na2CO3 increases the yields of total gas and also of hydrogen-rich gas. Catalytic performance of Na2CO3 shows a little bit better than that of CaCO3 in the case of rice straw pyrolysis.