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Physicochemical Features of Phosphorus-Modified ZSM-5 Zeolite and Its Performance on
Catalytic Pyrolysis to Produce Ethylene

KE Minga; WANG Xieqingb; ZHANG Fengmeib   

  1. a State Key Laboratory of Heavy Oil Processing, University of Petroleum,
    Beijing,102249,China
    b Research Institute of Petroleum Processing SINOPEC, Beijing,100083, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2003-12-28 Published:2003-12-28
  • Contact: KE Ming

磷改性ZSM-5分子筛物化性质和裂解制乙烯性能的研究

柯明a; 汪燮卿b; 张凤美b   

  1. a State Key Laboratory of Heavy Oil Processing, University of Petroleum,
    Beijing,102249,China
    b Research Institute of Petroleum Processing SINOPEC, Beijing,100083, China
  • 通讯作者: 柯明

Abstract: The physicochemical features of phosphorus-modified ZSM-5 zeolites (SiO2/Al2O3 molar ratio
is 25)were characterized by XRD(X-ray diffraction), BET(Brunauer, Emmett and Teller spcific
surface area measurement), NH3-TPD(ammonia temperature-programmed desorption) and MASNMR
(magic angle spinning nuclear magnetic resonance), and the performance on catalytic
pyrolysis to produce ethylene was investigated with a light hydrocarbon fixed bed micro-
reactor with n-octane as feed. The results show that the acid site density, acid intensity
and hydrothermal stability of ZSM-5 zeolite were improved by phosphorus modification. When
P2O5 content in ZSM-5 zeolite is higher than 2.5%, phosphorus modification can prevent ZSM
-5 zeolite crystal structure transformation from orthorhombic to monoclinic. In addition,
the dealumination of ZSM-5 zeolite framework was moderated by phosphorus modification under
high temperature hydrothermal treatment. The results of n-octane pyrolysis on phosphorus-
modified ZSM-5 zeolites show that ethylene yields of zeolites with different phosphorus
content are almost the same under the same n-octane conversion. However, the modified
zeolites with higher pyrolysis activity give lower yield of propene, butene and total
olefin than lower pyrolysis activity under the same n-octane conversion.

Key words: phosphorus-modified ZSM-5 zeolite, catalytic pyrolysis, ethylene, hydrothermal stability, magic angle spinning nuclear magnetic resonance

摘要: The physicochemical features of phosphorus-modified ZSM-5 zeolites (SiO2/Al2O3 molar ratio
is 25)were characterized by XRD(X-ray diffraction), BET(Brunauer, Emmett and Teller spcific
surface area measurement), NH3-TPD(ammonia temperature-programmed desorption) and MASNMR
(magic angle spinning nuclear magnetic resonance), and the performance on catalytic
pyrolysis to produce ethylene was investigated with a light hydrocarbon fixed bed micro-
reactor with n-octane as feed. The results show that the acid site density, acid intensity
and hydrothermal stability of ZSM-5 zeolite were improved by phosphorus modification. When
P2O5 content in ZSM-5 zeolite is higher than 2.5%, phosphorus modification can prevent ZSM
-5 zeolite crystal structure transformation from orthorhombic to monoclinic. In addition,
the dealumination of ZSM-5 zeolite framework was moderated by phosphorus modification under
high temperature hydrothermal treatment. The results of n-octane pyrolysis on phosphorus-
modified ZSM-5 zeolites show that ethylene yields of zeolites with different phosphorus
content are almost the same under the same n-octane conversion. However, the modified
zeolites with higher pyrolysis activity give lower yield of propene, butene and total
olefin than lower pyrolysis activity under the same n-octane conversion.

关键词: phosphorus-modified ZSM-5 zeolite;catalytic pyrolysis;ethylene;hydrothermal stability; magic angle spinning nuclear magnetic resonance