正己烷在HZSM-5分子筛上的催化裂解研究

为筛选反应活性和烯烃选择性相对较高的催化剂用于研究吸热型碳氢燃料的催化裂解，以正己烷的催化裂解作为探针反应，探讨其在不同硅铝物质的量比HZSM-5［n(Si)∶n(Al)=25、36、100］分子筛上催化裂解的反应活性和产物分布。结果表明，正己烷在HZSM-5分子筛上的裂解转化率随温度的升高和分子筛中硅铝物质的量比的减小而增大；裂解产物中乙烯、丙烯和总烯烃的选择性均随裂解温度的升高和分子筛中硅铝物质的量比的增加而增加，在（300~550） ℃，HZSM-5［n（Si)∶n(Al)=36］上的总烯烃收率最高，芳烃含量随分子筛中硅铝物质的量比的增加而减小；基于裂解转化率、烯烃和芳烃收率等因素综合考虑，HZSM-5 n(Si)∶n(Al)=36］分子筛为优选催化剂。

Catalytic cracking of n-hexane over HZSM-5 zeolites

HZSM-5 with different Si/A1 molar ratio was prepared as the catalyst for catalytic cracking of endothermic hydrocarbon fuels. Catalytic cracking of n-hexane was used as the probe reaction to investigate the activity and product distribution over HZSM-5 zeolite with n（ Si）： n（Al） of 25, 36 and 100. The results indicated that n-hexane conversion increased with reaction temperature and declined with Si/Al molar ratio. The selectivity to ethylene, propylene, and total olefins in the cracking products increased with cracking temperature and Si/Al molar ratio. Highest yield of total olefin was attained over HZSM-5 with n（Si）：n（M）of 36 at （300 -550） ℃. Aromatics content in the product decreased with Si/Al molar ratio. The HZSM-5 with n （Si） ： n （M） of 36 was screened out as the optimal catalyst in consideration of conversion and yield of both olefins and aromatics.