稀土对催化裂化催化剂抗钒污染性能的影响

Effect of Rare Earth Composition Introduction on Vanadium Tolerance of FCC Catalyst

采用沉淀法在USY分子筛中引入稀土(RE)组分La2O3、CeO2和LaPO4,分别制备得到La-USY、Ce-USY和LaPO-USY分子筛样品,系统研究了稀土抗钒组分对分子筛及催化剂物化性质和反应性能的影响。结果表明:La2O3和CeO2部分迁移到分子筛晶内,起到稳定骨架结构的作用,其余分散于分子筛表面;LaPO4主要分布于分子筛表层,对分子筛的性能影响不大。在钒污染分子筛和催化剂后,稀土组分均表现出优异的抗钒作用。与添加氧化稀土La2O3和CeO2的催化剂相比,引入LaPO4抗钒组分,催化剂LaPO-Cat具有最低的焦炭和干气选择性,表现出良好的抗钒污染性能。

Rare earth compounds(La2O3,CeO2 and LaPO4)were employed as vanadium traps for USY zeolite,with the preparation of La-USY,Ce-USY and LaPO-USY by precipitation method,respectively.Effects of different rare earth composition introduction on the physico-chemical properties and the catalytic performance of these catalysts were systematically investigated.Results show that some rare earth cations move to zeolite cages,improving the stability of framework structure,while others are dispersed on zeolite surface.LaPO4 is distributed on the zeolite surface,thus without any impact on catalytic properties.Compared with the rare earth oxide contained catalysts,LaPO-Cat catalyst showed a high tolerance to the vanadium presence,lower coke and dry gas selectivity.