Olefin selective FT catalyst composition and preparation thereof
AssigneesSasol Technology (Pty) Ltd, Sasol Wax GmbH
InventorsReinier Crous, Tracy Carolyn Bromfield, Sharon Booyens
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Abstract
The present invention relates to a hydrocarbon synthesis catalyst comprising in its unreduced form a) Fe as catalytically active metal, b) an alkali metal and/or alkaline-earth metal in an alkali metal- and/or alkaline-earth metal-containing promoter, the alkali metal, c) and a further promoter comprising, or consisting of, one or more element(s) selected from the group of boron, germanium, nitrogen, phosphorus, arsenic, antimony, sulphur, selenium and tellurium, to a process for the synthesis of a hydrocarbon synthesis catalyst, to a hydrocarbon synthesis process which is operated in the present of such a catalyst and to the use of such a catalyst in a hydrocarbon synthesis process.
Claims9
A hydrocarbon synthesis catalyst comprising:
- an unreduced form comprising:
- a) Fe as catalytically active metal,
- b) a first promoter comprising an alkali metal and/or an alkaline-earth metal, the alkali metal and/or alkaline-earth metal being present in a combined amount of 0.1 to 1.0 g/100 g Fe,
- c) a second promoter comprising a metalloid, the metalloid being antimony, present in an amount of 0.03 to 0.2 g/100 g Fe,
- d) a surface area of 80 m2/g or less, and
- e) a weight ratio of the first promoter to the second promoter of 0.8:1 to 20:1;
- and
- a reduced form comprising:
- a chemical bond between the at least one metal of the first promoter and the metalloid of the second promoter, and wherein at least 75 wt. % of the Fe is in the zero oxidation state.
A catalyst obtained by the following process steps:
- (a) providing a precipitation mixture comprising:
- a precipitated, non-calcined iron-containing solid;
- an aqueous solvent;
- and
- a precursor of a first promoter, the precursor comprising a metalloid which is antimony,
- (b) removing the aqueous solvent from the precipitation mixture while retaining the metalloid of the first precursor,
- (c) subjecting the product of step (b) to a calcination treatment to form a calcined catalyst, the calcined catalyst comprising an amount of the metalloid of the precursor of the first promoter present in an amount of 0.03 to 0.2 q/100 g Fe,
- (d) providing a precursor of a second promoter to the calcined catalyst, the second precursor comprising an alkali metal and/or an alkaline-earth metal, the second precursor provided to the calcined catalyst by at least one of the following steps:
- adding the second precursor to the precipitation mixture and retaining the metal of the second precursor while removing the aqueous solvent from the precipitation mixture;
- adding the second precursor to the precipitation mixture after the aqueous solvent has been removed;
- and
- adding the second precursor to the calcined catalyst,
- wherein the precursor of the second promoter is provided in amount sufficient to provide in the calcined catalyst a ratio of the metal of the second precursor to the amount of the metalloid of the first precursor of 0.8:1 to 20:1, and
- (e) reducing the calcined catalyst comprising the precursor of the second promoter, wherein the reduced form of the catalyst comprises a chemical bond between the metal of the second promoter and the metalloid of the first promoter, and wherein at least 75 wt. % of the Fe is in the zero oxidation state.
Dependencies are inferred from the claim text.