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用浸渍法制备负载型Ni-La_2O_3甲烷化催化剂,并在其中添加少量的贵金属(Ru 或Pd)。发现组份间存在着促进甲烷化反应的协同效应。认为主要催化活性组份为Ni;贵金属能增强组份间的氢溢流,Pd 含量为0.5%时具有最大的甲烷化活性。La_2O_3有增加金属Ni 分散度的作用,其含量低于6%时,催化活性随La 含量增加而上升。对Al_2O_3和SiO_2载体作了比较,推荐一种经1000℃热处理的AL_2O_3载体。在组成为4.0%Ni-2.3%La_2O_3-0.5%Pd/Al_2O_3的催化剂上,280℃时CO 的初始转化率达100%,CH_4的时空产率为16.4摩尔/小时·公斤(催化剂),气体产物中CH_4含量为93%,反应20小时后,活性逐渐趋于稳定,CO 转化率为76%。研究了在反应过程中催化剂活性的变化和碳沉积现象;以Al_2O_3为载体的催化剂的失活速率和积炭速率均低于以SiO_2为载体者,失活后,经空气烧焦可以再生.
Prepared by impregnation Ni - La 2 O 3 supported methanation catalyst, and add a small amount of precious metal (Ru or Pd). The synergistic effect of promoting methanation was found among the components. It is considered that the main catalytic active component is Ni; the noble metal can enhance the hydrogen overflow between the components, and has the maximum methanation activity when the Pd content is 0.5%. La 2 O 3 has the effect of increasing the dispersion degree of metal Ni. When the content of La 2 O 3 is less than 6%, the catalytic activity increases with the increase of La content. A comparison was made between Al 2 O 3 and SiO 2 carriers, and a kind of AL 2 O 3 carrier which was heat treated at 1000 ℃ was recommended. The initial conversion of CO at 280 ° C was 100% on a catalyst consisting of 4.0% Ni-2.3% La 2 O 3 -0.5% Pd / Al 2 O 3, the space time yield of CH 4 was 16.4 mol / h · kg (catalyst) CH_4 content of 93%, 20 hours after the reaction, the activity gradually stabilized, CO conversion was 76%. The changes of catalyst activity and carbon deposition during the reaction were studied. The deactivation rate and carbon deposition rate of catalysts supported on Al 2 O 3 were lower than that of SiO 2 carrier. After deactivation, the catalysts were regenerated by air scorch.