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Title: Fischer-Tropsch synthesis over reduced and unreduced iron oxide catalysts

Abstract

An investigation has been carried out of Fischer-Tropsch synthesis over potassium-promoted and unpromoted iron oxide catalysts. The distribution of products over reduced and unreduced Fe/sub 2/O/sub 3/ are similar. The primary products are methane and linear, terminal olefins. Some C/sub 2//sup +/ paraffins are produced in parallel with olefins, but most result from hydrogenation of the olefins. Isomerization of terminal to internal olefins also occurs as a secondary reaction. The Anderson-Schulz-Flory distribution of products is characterized by two branches differing in the value of ..cap alpha... The average molecular weight of the product increases with decreasing temperature, decreasing H/sub 2/ partial pressure, and increasing CO partial pressure. Methanol is the only oxygenated product formed over unpromoted Fe/sub 2/O/sub 3/. Promotion of Fe/sub 2/O/sub 3/ with potassium suppresses the rates of olefin hydrogenation and isomerization, and the rate of methanol formation, but enhances the rates of formation of C/sub 2//sup +/ hydrocarbons, branched hydrocarbons, and aldehydes. The kinetics for the synthesis of C/sub 1/-C/sub 7/ hydrocarbons were determined for both promoted and unpromoted catalysts. The data show that in general the kinetics of formation of an individual product cannot be represented by simple power-law rate expressions. Based on X-ray diffraction analysesmore » of used catalysts, it is concluded that the phase of iron active for Fe/sub 2/O/sub 3/ Fischer-Tropsch synthesis is a mixture of chi- and epsilon'-iron carbides, and a small amount of ..cap alpha..-iron. 39 references.« less

Authors:
;
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA (USA)
OSTI Identifier:
5297988
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Journal Name:
J. Catal.; (United States)
Additional Journal Information:
Journal Volume: 97:1
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; FISCHER-TROPSCH SYNTHESIS; CHEMICAL REACTION KINETICS; IRON OXIDES; CATALYTIC EFFECTS; POTASSIUM; ALKANES; ALKENES; CARBON MONOXIDE; CATALYSTS; CHEMICAL PROPERTIES; CHEMICAL REACTION YIELD; HYDROGEN; HYDROGENATION; ISOMERIZATION; METHANE; METHANOL; MOLECULAR WEIGHT; PARTIAL PRESSURE; PRESSURE DEPENDENCE; PROMOTERS; SURFACE PROPERTIES; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION; ALCOHOLS; ALKALI METALS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; COHERENT SCATTERING; DIFFRACTION; ELEMENTS; HYDROCARBONS; HYDROXY COMPOUNDS; IRON COMPOUNDS; KINETICS; METALS; NONMETALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; REACTION KINETICS; SCATTERING; TRANSITION ELEMENT COMPOUNDS; YIELDS; 010408* - Coal, Lignite, & Peat- C1 Processes- (1987-)

Citation Formats

Dictor, R A, and Bell, A T. Fischer-Tropsch synthesis over reduced and unreduced iron oxide catalysts. United States: N. p., 1986. Web. doi:10.1016/0021-9517(86)90043-6.
Dictor, R A, & Bell, A T. Fischer-Tropsch synthesis over reduced and unreduced iron oxide catalysts. United States. doi:10.1016/0021-9517(86)90043-6.
Dictor, R A, and Bell, A T. Wed . "Fischer-Tropsch synthesis over reduced and unreduced iron oxide catalysts". United States. doi:10.1016/0021-9517(86)90043-6.
@article{osti_5297988,
title = {Fischer-Tropsch synthesis over reduced and unreduced iron oxide catalysts},
author = {Dictor, R A and Bell, A T},
abstractNote = {An investigation has been carried out of Fischer-Tropsch synthesis over potassium-promoted and unpromoted iron oxide catalysts. The distribution of products over reduced and unreduced Fe/sub 2/O/sub 3/ are similar. The primary products are methane and linear, terminal olefins. Some C/sub 2//sup +/ paraffins are produced in parallel with olefins, but most result from hydrogenation of the olefins. Isomerization of terminal to internal olefins also occurs as a secondary reaction. The Anderson-Schulz-Flory distribution of products is characterized by two branches differing in the value of ..cap alpha... The average molecular weight of the product increases with decreasing temperature, decreasing H/sub 2/ partial pressure, and increasing CO partial pressure. Methanol is the only oxygenated product formed over unpromoted Fe/sub 2/O/sub 3/. Promotion of Fe/sub 2/O/sub 3/ with potassium suppresses the rates of olefin hydrogenation and isomerization, and the rate of methanol formation, but enhances the rates of formation of C/sub 2//sup +/ hydrocarbons, branched hydrocarbons, and aldehydes. The kinetics for the synthesis of C/sub 1/-C/sub 7/ hydrocarbons were determined for both promoted and unpromoted catalysts. The data show that in general the kinetics of formation of an individual product cannot be represented by simple power-law rate expressions. Based on X-ray diffraction analyses of used catalysts, it is concluded that the phase of iron active for Fe/sub 2/O/sub 3/ Fischer-Tropsch synthesis is a mixture of chi- and epsilon'-iron carbides, and a small amount of ..cap alpha..-iron. 39 references.},
doi = {10.1016/0021-9517(86)90043-6},
journal = {J. Catal.; (United States)},
number = ,
volume = 97:1,
place = {United States},
year = {1986},
month = {1}
}