纳米小晶粒EU-1分子筛的合成及其催化裂解反应性能

Synthesis and catalytic cracking reaction of nanoscale EU-1 zeolite

采用动态水热晶化法合成纳米小晶粒EU-1分子筛,通过在合成体系中加入表面活性剂十六烷基三甲基溴化铵以及一定量EU-1晶种的方法,动态水热条件下一步得到纳米小晶粒EU-1分子筛。详细研究表面活性剂用量、晶种含量以及转动烘箱转速对合成样品的影响,并在此基础上研究其催化裂解反应性能。结果表明,适当的表面活性剂用量、晶种含量以及转动烘箱转速更有利于纳米小晶粒EU-1分子筛的形成。过多的表面活性剂用量以及过快的转速均不利于分子筛稳定凝胶的形成,使所得样品为无定型硅铝凝胶以及结晶度较低的EU-1分子筛。另外,较高的晶种含量加快了EU-1晶体的形成,进而使所得样品晶粒尺寸较大。与传统静态水热法所得EU-1分子筛样品相比,纳米小晶粒EU-1分子筛表现出更多的介孔含量,而且酸量和酸强度均明显增加。催化裂解反应表明,纳米小晶粒EU-1分子筛具有更高的活性稳定性和低碳烯烃(乙烯和丙烯)收率,有望成为一种新型的工业催化裂解催化剂或添加剂,促进反应过程中低碳烯烃收率的提高。

Nanoscale EU-1 zeolite was synthesized by a dynamic hydrothermal method.By adding certain amount of surfactant cetyl trimethyl ammonium bromide and EU-1 seed into the synthesis system,nanoscale EU-1 zeolite was obtained by one step of the operation.The effects of the content of surfactant and EU-1 seed,and the speed of the rotating oven were studied in detai.The catalytic cracking performance was tested.The results show that appropriate surfactant and seed content and rotating oven speed are more conducive to the formation of nanoscale EU-1 zeolite.Too much surfactant content and fast rotating speed restrains the formation of stable gel,which results to the formation of amorphous gel or the EU-1 zeolite with low crystallinity.Moreover,the more seed content accelerates the formation of EU-1 crystal,and leading to the zeolite with large size.Compared with the traditional static hydrothermal method,the as-synthesized nanoscale EU-1 zeolite shows obvious mesoporous content and increased acid content and strength,and further exhibites higher reactive stability and yield of light olefins(ethylene and propylene)in the catalytic cracking reaction.Nanoscale EU-1 zeolite will be a new catalyst or additive of industrial catalyst to improve the yield of light olefins in the catalytic cracking reaction process.