Synthesis of Tailored Eggshell Cobalt Catalysts for Fischer–Tropsch Synthesis Using Wet Chemistry Techniques

Eggshell cobalt catalysts are used in CO hydrogenation reactions due to their ability to maximize the use of precious cobalt metal. The thickness of the shell can be utilized to control the product yield and distribution. In this article, we describe how the metal support interaction can be exploite...

Full description

Saved in:
Bibliographic Details
Published in:Industrial & engineering chemistry research 2012-02, Vol.51 (4), p.1703-1712
Main Authors: Gardezi, Syed Ali, Landrigan, Lucky, Joseph, Babu, Wolan, John T
Format: Article
Language:English
Subjects:
Applied sciences
Catalysis
Catalysts
Catalytic reactions
Chemical engineering
Chemistry
Cobalt
Ethyl alcohol
Exact sciences and technology
General and physical chemistry
Kinetics, Catalysis, and Reaction Engineering
Mathematical analysis
Reactors
Silica gel
Solvents
Synthesis
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Eggshell cobalt catalysts are used in CO hydrogenation reactions due to their ability to maximize the use of precious cobalt metal. The thickness of the shell can be utilized to control the product yield and distribution. In this article, we describe how the metal support interaction can be exploited to control the thickness and, hence, the product distribution. The catalysts are prepared using precipitation of cobalt nitrate solution (dissolved in ethanol) on silica. The metal deposition rate and location are controlled through optimized nonpolar solvent imbibing, followed by water addition to a Co(NO3)2-ethanol solution and hydrolysis by urea. The eggshell coating thickness (in the absence of restricting solvent) onto silica gel substrate has been determined via theoretical equations and experimentally verified during catalyst preparation through microscopic analysis of catalyst samples. Bulk precursor solution properties such as viscosity and surface tension along with substrate properties such as tortuosity are analyzed and included in the theoretical analysis for tailoring the catalyst eggshell thickness. Polar and nonpolar solvent interactions are exploited during precipitation of silica gel as a factor in controlling the eggshell thickness. The optimized samples are characterized using hydrogen chemisorption studies. The catalyst was tested in a fixed-bed tubular bench scale reactor using a research-grade synthetic feed (H2/CO being 2:1). Products were analyzed using gas chromatography and compared with Anderson–Schulz–Flory distribution. Liquid product analysis validated the approach used for effectual eggshell catalyst design and synthesis.
ISSN:0888-5885
1520-5045
DOI:10.1021/ie200927g