Sasol Technology Proprietary Limited

Engelhard De Meern B.v.

Hans Marcel Veltman

Jacobus Lucas Visagie

Jan Van De Loosdrecht

Peter Jacobus Van Berge

Tjaart Jurgens Van Der Walt

Johan Coenraad Sollie

Sylvia Sollie-Breur, Legal Representative

A particulate pre-reduction cobalt supported Fischer-Tropsch synthesis catalyst precursor which comprises a catalyst support impregnated with cobalt, is treated with a pure hydrogen reducing gas, at a first specific feed gas space velocity, SV1, and at a first heating rate, HR1, to obtain a partially reduced precursor. The support contains reducible cobalt oxide in a calcined state and having a formula-unit in which each mole of cobalt atoms is associated with more than 4/3 moles of oxygen atoms and displaying a reducible cobalt oxide specific surface area at least equal to that of CoOspinel. The partially reduced precursor is then treated with a pure hydrogen reducing gas, at a second specific feed gas space velocity, SV2, and at a second heating rate, HR2, to obtain an activated supported Fischer-Tropsch catalyst, with SV2&#x2266;SV1 and/or HR2&#x2267;HR1; however, when SV2=SV1, HR2&#x2260;HR1 and when HR2=HR1, SV2&#x2260;SV1.

Process for activating cobalt catalysts

A process for producing a supported Fischer-Tropsch catalyst includes treating, in an activation stage (), a particulate pre-reduction cobalt nitrate-based supported Fischer-Tropsch synthesis catalyst precursor containing reducible cobalt oxides, with hydrogen as a reducing gas in order to reduce the cobalt oxides over a period of time to Co, with ammonia and water being formed, the reduction including a time period when predominantly CoO is reduced to Co. Unreacted hydrogen is withdrawn (), which thus includes water and treated to lower its dewpoint (). At least a portion of the withdrawn unreacted hydrogen is returned to the activation stage () as recycle hydrogen (). An ammonia concentration is maintained in the activation stage (), at least during the time when predominantly CoO is reduced to Co, of less than 250 volume parts per million ('vppm').

Producing supported cobalt catalysts for the Fisher-Tropsch synthesis

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Utrecht, Netherlands

Hans Marcel Veltman