C4烯烃转化制丙烯工艺及催化剂研究

Research on the process of C4 olefins to propylene and catalysts

关键词:  C₄烯烃  催化裂解  ZSM-5分子筛  催化剂活性  丙烯 

Key words:  C₄ olefins  catalytic cracking  ZSM-5 zeolite  catalyst activity  propylene

摘要:

目的 开发C₄烯烃催化裂解制丙烯工艺和催化剂制备工艺技术,完成小试和工业侧线试验。方法 采用固定床评价装置考查了催化剂配方、改性及工业条件对催化剂活性、选择性、稳定性能的影响。结果 以ZSM-5分子筛为活性组分的催化剂在C₄烯烃转化制丙烯反应中具有较好的活性、选择性、稳定性和再生性,磷的引入未改变催化剂的晶型结构,但降低了催化剂酸性位点数量,并调节了催化剂的n(B酸)/n(L酸),随着磷负载量增加到5%(w),分子筛中磷与铝的相互作用逐渐增强,磷可以和骨架铝和非骨架铝相互作用。结论 C₄烯烃的转化率达到80%以上,丙烯的选择性达到35%~45%,催化剂的单程寿命达到一个月以上,且经再生后,再生恢复率达95%。 

Abstract:

Objective To develop the process of catalytic cracking of C₄ olefins to propylene and the catalyst preparation technology, the pilot test and industrial side line test are completed. Methods The fixed-bed evaluation apparatus was used to investigate the impact of catalyst formulation, modification, and industrial conditions on catalyst activity, selectivity, and stability. Results The catalyst with ZSM-5 zeolite as the active component had good activity, selectivity, stability and regeneration performance in the conversion of C₄ olefins to propylene. The introduction of phosphorus did not change the crystal structure of the catalyst, but it reduced the number of acidic sites on the catalyst, and adjusted the molar ratio of B acid and L acid of ZSM-5 zeolite. With the increase of phosphorus loading to 5 wt%, the interaction between phosphorus and aluminum in molecular sieves was gradually strengthened, and phosphorus could interact with framework aluminum and non-framework aluminum. Conclusion sThe conversion rate of C₄ olefins is more than 80%, the selectivity of propylene is 35%-45%, the once-through life of catalyst is more than one month, and the regeneration recovery rate is 95%.