纳米片型MFI分子筛超临界催化裂解正十二烷和煤油对比研究

发布时间：2018-02-27 01:12

  本文关键词： 纳米片型MFI分子筛 催化裂解 碳氢燃料 低碳烯烃 热沉　出处：《西安交通大学学报》2017年11期 　论文类型：期刊论文

【摘要】：针对传统ZSM-5分子筛孔径小、反应物分子扩散路径长、催化活性稳定性较差等问题,通过水热法合成了具有更高催化活性及稳定性的纳米片型MFI分子筛(Nanosheet MFI,NS-MFI),并通过XRD、BET、SEM、TEM和NH3-TPD表征,分别以正十二烷和煤油为超临界催化裂解底物,测试了NS-MFI的催化活性及稳定性,并与传统的ZSM-5分子筛进行比较。与ZSM-5分子筛相比,NS-MFI具有更高的比表面积、更大的孔容、更薄的片层结构。在裂解正十二烷时,NS-MFI催化裂解的产气率更高,低碳烯烃的选择性更高,产生的热沉值更大。裂解煤油时,在550℃时,由于煤油中含有大量的环烷烃,使其更难被裂解,两种分子筛催化裂解的活性相当;在600℃时,NSMFI具有比ZSM-5更高的催化活性。两种分子筛裂解煤油的活性均低于裂解正十二烷的活性,多级孔道结构及较薄的片层结构有利于反应物及产物的扩散,可提高催化剂的反应活性及稳定性。
[Abstract]:In view of the problems of small pore size, long molecular diffusion path of reactants and poor catalytic activity stability of traditional ZSM-5 molecular sieves, Nanosheet MFI molecular sieves with higher catalytic activity and stability were synthesized by hydrothermal method, and characterized by TEM and NH3-TPD. The catalytic activity and stability of NS-MFI were tested by using 12 alkane and kerosene as supercritical catalytic cracking substrates, and compared with traditional ZSM-5 molecular sieve. Compared with ZSM-5 molecular sieve, NS-MFI has higher specific surface area and larger pore volume. A thinner lamellar structure. When cracking 12 alkanes, the catalytic cracking of NS-MFI has higher gas yield, higher selectivity of low olefins and higher heat sink. When pyrolysis kerosene, at 550 鈩，

本文编号：1540473