柠檬酸凝胶法合成Ni-ZrO_2催化剂及其低温浆态床甲烷化性能研究  

Ni-ZrO_2 Catalysts Prepared by Citric-gel Method for Lowtemperature Slurry Phase Methanation of Carbon Monoxide

作　　者：宋燕[1] 孟凡会[1] 李忠[1] 

机构地区：[1]太原理工大学煤化工研究所,煤科学与技术教育部和山西省重点实验室,山西太原030024

出　　处：《分子催化》2016年第3期243-252,共10页Journal of Molecular Catalysis(China)

基　　金：山西省青年基金(No.2013021007-4);国家“973”计划(No.2012CB723105)资助项目~~

摘　　要：采用柠檬酸凝胶法制备不同温度焙烧的Ni-ZrO_2催化剂,考察了催化剂的表面性质和结构对低温浆态床CO甲烷化性能的影响.结果表明,随着焙烧温度的升高,催化剂的比表面积和孔容逐渐减小,金属Ni分散度先增加后减小,Ni晶粒先减小后增大.450℃焙烧的Ni-ZrO_2催化剂金属Ni分散度最高、Ni物种与载体ZrO_2的相互作用最强、对反应物CO分子的吸附作用适中且脱附量大,在260℃、1.0 MPa和H_2/CO摩尔比为3的条件下,CO转化率达到61.6%,且催化活性稳定,750℃焙烧的催化剂反应后金属Ni团聚且晶粒长大,导致催化剂失活.A series of Ni-ZrO_2 catalysts were prepared by the citric-gel method and calcined at different temperatures. The effect of physiochemical properties and structures on catalytic activity of Ni-ZrO_2 catalysts for low-temperature CO methanation in a slurry-bed reactor was studied. As the calcination temperature rose,the BET specific surface area and pore volume decreased,the Ni metal dispersion firstly increased and then decreased,while the Ni particle size firstly decreased and then increased. Ni-ZrO_2 catalyst calcinated at 450 ℃ showed the highest Ni dispersion,smallest Ni crystallite size,strongest interaction between Ni species and support,and largest amount of CO desorption which moderate interacted with metallic Ni. Under the conditions of 260 ℃,1. 0 MPa and H_2/ CO molar ratiao of 3,Ni-ZrO_2 catalyst showed the highest CO conversion of 61. 6% and stable catalytic activity. The Ni aggregation and Ni crystallite size growth of Ni-ZrO_2 catalyst calcined at 750 ℃ led to the catalyst deactivation.

关 键 词：浆态床反应器 CO甲烷化 Ni-ZrO_2催化剂 焙烧温度 

分 类 号：O643.32[理学—物理化学]