Ni-CeO2/Al2 O3催化剂的制备、表征及其生物质合成气甲烷化性能研究

摘要

A series of Ni-based catalysts with addition of different additives (CeO2 ,ZrO2 ,Co3 O4 ,Y2 O3 , V2 O5 )were prepared by a co-impregnation method.The structure of the catalysts was characterized by XRD, SEM,BET,H 2-TPR,etc.Effects of Ni content,additive content,impregnation order,calcination temperature, reduction temperature and space velocity(SV)on the catalytic activity were investigated.The catalytic perform-ance for methanation of biomass syngas was evaluated.Results showed that,adding CeO2 ,ZrO2 ,Y2 O3 ,V2 O5 could improve the catalytic activity for methanation of CO,and the catalyst 6Ni-3CeO2/Al2 O3 had the highest catalytic activity,the best stability and the best coke resistance.Using 6Ni-3CeO2/Al2 O3 as a catalyst,CO could be completely converted at conditions as follows:V (H 2 )∶V (CO)∶V (N2 )=0.45 ∶0.15 ∶0.40,SV=20 000 h-1 ,atmosphere pressure,350 ℃,CH 4 selectivity reached 90%,which increased by 1 6% than that of catalyst 6Ni/Al2 O3 ,the temperature of CO completely conversion was 50 ℃ lower than that of catalyst 6Ni/Al2 O3 .The Ni content of catalyst 6Ni-3CeO2/Al2 O3 was obviously lower than that of reported in literature.The catalyst was applied to methanation of biomass syngas by catalytic hydrogenation with CO conversion rate of 80.5%, and the problem “CO content in biomass syngas is higher than civil gas standard”was effectively solved.%采用共浸渍法制备了添加不同助剂(CeO2、ZrO2、Co3 O4、Y2 O3、V2 O5)的一系列 Ni 基催化剂,采用 XRD、SEM、BET、H 2-TPR 等对催化剂的结构进行表征,对 Ni 含量、助剂含量、浸渍顺序、焙烧温度、还原温度、空速等条件进行优化,并考察了催化剂的生物质合成气甲烷化性能。结果表明：助剂 CeO2、ZrO2、Y2 O3、V2 O5的加入均能提高催化剂对 CO 甲烷化的催化活性,其中6Ni-3CeO2/Al2 O3的催化活性、稳定性和抗积碳能力最好；采用6Ni-3CeO2/Al2 O3催化剂,在V (H 2)∶V (CO)∶V (N2)=0.45∶0.15∶0.40、空速为20000 h-1、常压、350℃下,CO 即可完全转化,甲烷选择性达到90%,较6Ni/Al2 O3催化剂提高了16%,CO 完全转化温度较6Ni/Al2 O3催化剂低50℃。6Ni-3CeO2/Al2 O3催化剂的 Ni 含量明显低于文献报道,应用于生物质合成气催化加氢转化为甲烷,CO 转化率达到80.5%,有效地解决了生物质合成气中 CO 含量高于民用燃气标准的问题。