赤泥基ZSM-5分子筛的合成及其催化裂解性能

Synthesis of red mud-based ZSM-5 zeolite and its catalytic cracking performance

使用工业固废赤泥和水玻璃进行ZSM-5分子筛的制备研究,调查了赤泥碱熔活化、赤泥添加量、模板剂(四丙基溴化铵、葡萄糖)用量等合成因素;并对低密度聚乙烯进行催化裂解研究,考察其催化裂解性能。结果表明,赤泥经过碱熔活化后,硅酸铝被转化为了铝酸钠;将碱熔赤泥、四丙基溴化铵、葡萄糖、水玻璃、去离子水以1.5∶0.8∶3.6∶24∶18的质量比混合、水热晶化后得到了ZSM-5。并在剂料比为5∶3、500℃下进行裂解实验,液体和气体产率分别为13%和84%,其中单环芳烃和低碳烯烃(C_(2-4)^(=))选择性分别为47%和75%,在生产苯、甲苯、二甲苯及乙烯、丙烯等方面展示了较好的应用前景。

ZSM-5 Zeolites were economically synthesized with industrial solid waste(red mud)and water glass as the raw materials.The effects of alkali fusion activation of red mud(AF-RM)and the addition amounts of AF-RM and templates(tetrapropylammonium bromide(TPABr),glucose)on the formation of zeolites were investigated.The catalytic performance of the synthesized zeolites were tested by cracking of low-density polyethylene.The results show that aluminum silicate in red mud can be transferred into sodium aluminate and sodium silicate by alkali fusion activation.ZSM-5 Can be obtained at a AF-RM∶TPABr∶glucose∶water glass∶deionized water mass ratio of 1.5∶0.8∶3.6∶24∶18.The obtained liquid and gaseous yields at catalyst-to-feed ratio of 5∶3 and 500℃are 13%and 84%,respectively.Thereinto,the selectivity to the monocyclic aromatics and light olefins(C_(2-4)^(=))are 47%and 75%,respectively,suggesting good application prospect in production of benzene,toluene,xylene,ethylene and propylene.