基于Ni/Al2O3整体式催化剂的生物质气化合成气甲烷化研究

以生物质气化模拟合成气H2/CO/N2为原料气,以堇青石蜂窝陶瓷为基体制备Ni/Al2O3整体式催化剂,通过扫描电镜(SEM)、比表面积(BET)、X射线衍射(XRD)、程序升温反应法(TPR)、热重分析(TG)等表征分析手段,考察催化剂制备方法(浸渍法和溶胶-凝胶法)、温度(250~550℃)及空速GHSV(6000~14000 mL/(g·h))对催化剂甲烷化性能的影响。结果表明:浸渍法制备的Ni/Al2O3催化剂(DIP-Ni/Al2O3)与溶胶-凝胶法制备的Ni/Al2O3催化剂(SGNi/Al2O3)相比,前者甲烷化性能较好。在H2、CO、N2物质的量之比为3∶1∶1且空速为10000 mL/(g·h)条件下,浸渍法制备的Ni/Al2O3催化剂在400℃时甲烷化性能最佳,且该条件下CO转化率为98.6%,CH4选择性为90.9%。当H2、CO、N2物质的量之比为3∶1∶1且温度为400℃时,在实验空速范围内,浸渍法制备的Ni/Al2O3催化剂CO转化率和CH4选择性均基本稳定在90%,甲烷化性能较好。

STUDY ON METHANATION OF BIOMASS GASIFICATION SYNGAS BASED ON Ni/Al2O3 MONOLITHIC CATALYSTS

In this study,synthesis gas of biomass gasification H2/CO/N2 was used as raw material gas,and Ni/Al2O3 monolithic catalysts was prepared from cordierite honeycomb ceramics. The effects of catalyst preparation method(dipping method and sol-gel method),temperature(250-550 ℃)and space velocity(6000-14000 mL/(g·h))on the methanation performance of the catalyst were investigated by employing the characterization methods of SEM,BET,XRD,TPR and TG. The results show that the methanation performance of the Ni/Al2O3 catalyst prepared by the dipping method(DIP-Ni/Al2O3)is better,compared with the sol-gel method(SG-Ni/Al2O3). The DIP-Ni/Al2O3 catalyst gives the best methanation performance at 400 ℃,CO conversion and CH4 selectivity reach 98.6% and 90.9% respectively when the molar ratio of H2,CO,N2 is around 3∶1∶1 and space velocity is 10000 m L/(g·h). The CO conversion and CH4 selectivity are basically stable at about 90% for the DIP-Ni/Al2O3 catalyst in the experimental space velocity range when the molar ratio of H2,CO,N2 is around 3∶1∶1 and temperature is 400 ℃,in which the catalyst has better methanation properties in the optimal conditions.