镁碱沸石分子筛催化剂的制备

Preparation of ferrierite zeolite catalysts

采用自制镁碱沸石分子筛为活性组分,考察不同用量拟薄水铝石为黏结剂、不同用量田菁粉为助挤剂、不同温度下焙烧的催化剂径向抗压碎力和正丁烯骨架异构性能,并对比以乙酸和硝酸为胶溶剂时催化剂的物化性能。采用XRD和NH3-TPD表征催化剂,分析其结构和酸性,测定径向抗压碎力,并在固定床反应器上进行正丁烯骨架异构化反应评价,对比采用不同成型条件制备的催化剂物化性能差异。结果表明,硝酸胶溶效果优于乙酸,在黏结剂拟薄水铝石质量分数为20%、助挤剂田菁粉质量分数为3%、胶溶剂质量分数为2%硝酸和柠檬酸(硝酸与柠檬酸物质的量比为2∶1)条件下,催化剂径向抗压碎力高于70 N·cm-1,正丁烯异构化反应活性高,异丁烯选择性和稳定性良好。

Using ferrierite zeolite as active component,pseudo boehmite as the binding agent,sesbania powder as the extrusion promoter,and acetic acid and nitric acid as the peptizers,the effects of the amounts of binding agent and extrusion promoter,and the types and dosages of the peptizers and calcination temperatures on the molded strength and the performance of ferrierite zeolite catalysts for n-butene skeletal isomerization were investigated.The extruded catalysts calcined at different temperatures were tested in a fixed-bed reactor to evaluate their performance for n-butene skeleton isomerization.The as-prepared catalysts were characterized by XRD and NH3-TPD.The results showed that the peptization effect of nitric acid was better than that of acetic acid,and the extruded catalyst with the best strength were obtained when the molecular sieve powder was mixed with 20wt％ binding agent pseudo boehmite,3wt％ extrusion promoter sesbania powder and the peptizer 2wt％ nitric acid and citric acid（nitric acid/citric acid molar ratio =2∶1）.The catalyst with the crush strength of more than 70 N · cm-1 exhibited high activity and selectivity,and good stability.