以碱液处理ZSM-5分子筛为载体的Pt-Sn-Na丙烷脱氢制丙烯催化剂  

Investigation of Pt-Sn-Na catalyst with alkali treated ZSM-5 as support for propane dehydrogenation

作　　者：黄力 王向华 徐隽 李庆宁[2] 田晓明[2] 孙勇[3] 

机构地区：[1]南京沃来德能源科技有限公司,江苏南京210042 [2]中国石化金陵石化分公司质检中心,江苏南京210033 [3]中国石化金陵石化分公司烷基苯厂,江苏南京210046

出　　处：《石化技术与应用》2015年第3期216-220,共5页Petrochemical Technology & Application

摘　　要：通过碱液处理使ZSM-5分子筛产生介孔结构,随后以其为载体,制备了丙烷脱氢制丙烯催化剂。采用N2-物理吸附法考察了碱液处理后分子筛孔结构的变化,使用NH3-程序升温脱附、H2-程序升温还原、O2-程序升温氧化对催化剂性能进行了评价。结果表明,碱液处理后,ZSM-5分子筛的外比表面积和总孔容增加,有利于催化剂活性中心Pt的分散和烃类分子的扩散和脱附;同时,分子筛的强酸中心明显减弱,提高了催化剂的抗积炭能力。反应7 h后,采用Pt-Sn-Na/ZP催化剂(未经碱液处理)丙烷转化率由31.2%降至28.6%,Pt-Sn-Na/ZA催化剂(碱液处理)则由32.0%降至29.6%,说明后者的脱氢活性较前者高。此外,与前者相比,后者的Pt分散度高,失活率和积炭质量分数低,表明后者的脱氢反应稳定性好。Mesoporous structure was formed by treating ZSM- 5 zeolite with Na OH solution,and using the obtained zeolite as supporter,the catalyst of propane dehydrogenation for propylene was prepared. The change of pore structure of molecular sieve treated by Na OH was characterized by N2-adsorption analysis. And the catalytic performance was evaluated by NH3temperature- programmed desorption,H2temperature- programmed reduction,and O2temperature- programmed oxidation techniques. The results showed that the alkali treatment increased the specific surface area and pore volume of ZSM- 5 zeolite,which facilitated the dispersion of Pt and the adsorption and desorption of hydrocarbon molacules. Meanwhile,the strong acid sites of the zeolite decreased,thus enhancing the carbon deposit resistance of the catalyst. After 7 h on stream,the propane conversion on Pt- Sn- Na / ZP catalyst（ without alkali treatment） decreased from 31. 2% to28. 6% and that on Pt- Sn- Na / ZA catalyst（ with alkali treatment） from 32. 0% to 29. 6%,indicating that the latter had higher activity of dehydrogenation. Besides,Pt- Sn- Na / ZA catalyst possessed higher Pt dispersion,lower deactivation rate and smaller amount of coke than that of Pt- Sn- Na / ZP catalyst. Accordingly,Pt- Sn- Na / ZA catalyst exhibited better dehydrogenation stability.

关 键 词：丙烷脱氢 丙烯 ZSM-5分子筛 碱液处理 Pt-Sn-Na/ZSM-5催化剂 介孔 

分 类 号：TQ221.212[化学工程—有机化工]