Cobalt catalysts
AssigneeJohnson Matthey PLC
InventorsHamera Abbas, Sharon Bale, Gordon James Kelly, John West
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Abstract
A catalyst suitable for the Fischer-Tropsch synthesis of hydrocarbons is described comprising cobalt nanocrystallites containing a precious metal promoter, dispersed over the surface of a porous transition alumina powder wherein the cobalt content of the catalyst is ≧25% by weight, the precious metal promoter metal promoter content of the catalyst is in the range 0.05 to 0.25% by weight, and the cobalt crystallites have a average size, as determined by hydrogen chemisorption, of ≧15 nm. A method for making the catalyst is also described.
Claims37
A catalyst suitable for the Fischer-Tropsch synthesis of hydrocarbons, comprising cobalt crystallites containing a precious metal promoter, dispersed over a surface of a porous transition alumina powder, wherein a cobalt content of the catalyst is ≧25% by weight, a precious metal promoter content of the catalyst is in the range 0.05 to 0.25% by weight, and the cobalt crystallites have an average size, as determined by hydrogen chemisorption, of ≧15 nm.
A process for preparing a catalyst comprising the steps of:
- (a) forming a catalyst precursor by;
- (i) impregnating a transition alumina with a cobalt compound and a precious metal promoter compound, and
- (ii) drying the impregnated alumina to produce a dried catalyst precursor,
- (b) calcining the dried catalyst precursor at a temperature in the range 250 to 650° C. to produce a calcined precursor, and
- (c) reducing the calcined precursor at a temperature in the range 450 to 650° C.,
- wherein steps (i) and (ii) are performed until a cobalt content of the catalyst is ≧25% by weight and a precious metal promoter content of the catalyst is in the range 0.05 to 0.25% by weight, such that cobalt crystallites in the catalyst have an average size, as determined by hydrogen chemisorption, of ≧15 nm.
A process for the Fischer-Tropsch synthesis of hydrocarbons comprising the step of passing a gas mixture comprising hydrogen and carbon monoxide over a catalyst in a Fischer-Tropsch reactor, the catalyst comprising cobalt crystallites containing a precious metal promoter, dispersed over the surface of a porous transition alumina powder, wherein a cobalt content of the catalyst is ≧25% by weight, a precious metal promoter content of the catalyst is in the range 0.05 to 0.25% by weight, and the cobalt crystallites have an average size, as determined by hydrogen chemisorption, of ≧15 nm.
Dependencies are inferred from the claim text.