焙烧温度对双金属催化剂甲苯加氢重整反应催化性能的影响

以类层柱Ni-Co/Mg(Al)O水滑石为前驱体，经不同温度焙烧制备了系列焦炉煤气中焦油模型化合物甲苯加氢重整制合成气催化剂. 在常压、反应温度800℃、水/碳摩尔比0.7和体积空速12000 h-1的条件下，在35 h评价时间内850℃焙烧的催化剂可完全转化甲苯，CH4和CO的平均产率分别为34%和66%，而低于750和高于950℃焙烧的催化剂活性较差. 850℃焙烧时催化剂比表面积较大，形成了尖晶石和固溶体，活性金属与载体间的相互作用较强，还原后活性金属颗粒小且均匀分布. 催化剂上有少量须状碳生成，绝大部分积碳可被H2消除，积碳是可逆过程.

Effect of Calcination Temperature on Catalytic Performance of Bimetallic Catalysts for Hydrogenation Reforming of Toluene

A series of Ni-Co/Mg(Al)O catalysts were prepared by calcination of Ni-Co/Mg(Al)O hydrotalcite precursor at various temperatures and used in the hydrogenation reforming reaction of toluene as a model tar compound. A C7H8 conversion rate of 100%, CH4 yield of 34% and CO yield of 66% were achieved for 35 h over the catalyst calcined at 850℃ under atmospheric pressure at 800℃ and GHSV of 12000 h-1 with a H2O/C molar ratio of 0.7, which was better than those calcined at the temperature lower than 750℃ or higher than 950℃. The catalyst calcined at 850℃ showed higher specific surface area, stronger interaction between active metals and carrier due to the formation of spinel and solid solution phases as well as smaller particulates and highly homogeneous dispersion of active metals. After the activity test, a small amount of whisker carbon was observed on the used catalyst, and most of it could be removed in the hydrogen-rich atmosphere. The carbon deposition on catalysts was a reversible process.