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| 2002 ,Vol.11 ,No.1,79-86 |
ISSN 1003-9953
CN 21-1484/O4 |
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| Dealuminated ZSM-5 Zeolite Catalyst for Ethylene Oligomerization to Liquid Fuels |
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| Abstract Ethylene oligomerization using ZSM-5 zeolite was investigated to study the role of Bronsted
acid sites in the formation of higher hydrocarbons. The oligomerization of olefins, dependent on the acidity
of ZSM-5 zeolite, is an important step in the conversion of natural gas to liquid fuels. The framework Si/Al
ratio re
ects the number of potential acid sites and the acid strength of the ZSM-5 catalyst. ZSM-5 with
the mole ratio SiO2/Al2O3 equal to 30 was dealuminated for di erent periods of time according to the
acidic ion-exchange method to produce ZSM-5 with various Si/Al ratios. The FT-IR analysis revealed
that the integrated framework aluminum band, non-framework aluminum band, and silanol groups areas
of the ZSM-5 zeolites decreased after being dealuminated. The performance of the dealuminated zeolite
was tested for ethylene oligomerization. The results demonstrated that the dealumination of ZSM-5 led
to higher ethylene conversion, but the gasoline selectivity was reduced compared to the performance of a
ZSM-5 zeolite. The characterization results revealed the amount of aluminum in the zeolitic framework,
the crystallinity of the ZSM-5 zeolite, and the Si/Al ratio a ected the formation of Bronsted acid sites.
The number of the Bronsted acid sites on the catalyst active sites is important in the olefin conversion to
liquid hydrocarbons. |
KEYWORS:
ethylene
liquid fuels
oligomerization
dealumination
ZSM-5
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