Interaction of water with the surface of a zeolite catalyst during catalytic cracking: a spectroscopy and kinetic study

被引：38

作者：

Corma, A ^{[1
]}

Marie, O ^{[1
]}

Ortega, FJ ^{[1
]}

机构：

[1] Univ Politecn Valencia, CSIC, UPV, Inst Tecnol Quim, E-46022 Valencia, Spain

来源：

JOURNAL OF CATALYSIS | 2004年 / 222卷 / 02期

关键词：

catalytic cracking; hydrocarbons adsorption; water adsorption; micro activity test; hydrogen transfer; olefins; dilution;

D O I：

10.1016/j.jcat.2003.11.006

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The potential effects of water on the conversion of Lewis into Bronsted acid sites and on the competitive adsorption with hydrocarbons for acid sites during hydrocarbon cracking with zeolites have been investigated by means of in situ infrared spectroscopy (IR) at reaction temperatures, as well as by studying the kinetics of n-hexadecane cracking. Both in situ IR and kinetic results show that under the cracking reaction conditions neither an increase of Bronsted acidity nor a competing adsorption effect of water occurs. On the contrary, the role of water is the same as that of nitrogen, i.e., to act as diluent, improving feed hydrocarbon dispersion and increasing the relative rate of unimolecular cracking versus bimolecular cracking and hydrogen transfer reactions. We also show that the mechanistic information achieved by spectroscopic and kinetic studies can be directly extrapolated to explain the effects observed when cracking industrial vacuum gas oil feed using water as dispersant. (C) 2003 Elsevier Inc.

引用

页码：338 / 347

页数：10

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