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Deactivation behavior of ruthenium promoted Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
42984 45950 2008 7 PDF Available
Title
Deactivation behavior of ruthenium promoted Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis
Abstract

Detailed activity study and the deactivation of Ru-Co/γ-Al2O3 catalyst for Fischer–Tropsch (FT) synthesis over 1000 h was investigated considering different deactivation mechanisms. Morphology changes of the catalyst during FT synthesis were studied using XRD, TPR, BET, ICP, carbon determination, H2 chemisorption and re-oxidation techniques. When the PH2O/(PH2+PCO)PH2O/(PH2+PCO) in the reactor is above 0.75 the deactivation rate is not dependent on the number of the catalyst active sites and is zero order to CO conversion. In this case the main deactivation mechanisms are: cobalt re-oxidation, metal support interactions and aluminates formation. The deactivation of Ru-Co/γ-Al2O3 is related to cobalt cluster size. At lower amounts of PH2O/(PH2+PCO)PH2O/(PH2+PCO) deactivation can be simulated with a power law expression with a power order of 39.7 and the main deactivation is due to sintering. Regeneration of catalyst at 275 °C recovered the catalyst activity by 69.9% of total activity loss due to the reduction of oxidized cobalts. Catalyst regeneration at 400 °C recovered the activity by 21.9% of total activity loss due to the reduction of refractory forms of oxidized cobalt generated by cobalt–alumina interactions. 7.2% of total activity loss is irreversible and can be assigned to aluminates formation, sintering and coke deposition.

Graphical abstractWhen PH2O/(PH2+PCO)>0.75PH2O/(PH2+PCO)>0.75 the deactivation rate of Ru-Co/γ-Al2O3 is zero order and is due to cobalt oxidation and metal support interactions. At lower PH2O/(PH2+PCO)PH2O/(PH2+PCO) deactivation is a power law expression with a power order of 39.7 and is due to sintering. 69.9% of total activity loss is due to oxidation, 21.9% is due to metal support interactions and 7.2% is due to sintering, aluminates and coke formation. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
FT, Fischer–Tropsch; ASF, Anderson–Schultz–Floury; GC, gas chromatograph; HC, hydrocarbonment; S, selectivityFischer–Tropsch; Cobalt catalyst; Deactivation; Activity recovery; Modeling
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Deactivation behavior of ruthenium promoted Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 346, Issues 1–2, 31 August 2008, Pages 58–64
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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