Attrition resistance of cobalt F–T catalysts for slurry bubble column reactor use

Abstract

There exists much current interest in the use of supported Co catalysts and slurry bubble column reactors (SBCR) for the conversion of natural gas to higher hydrocarbons via the Fischer–Tropsch (F–T) synthesis. Catalyst attrition resistance is extremely important in the operation of slurry-phase reactor systems because of potential problems with plugging of system filters and/or contamination of the liquid products. This paper addresses the effects of different supports, promoters, and preparation methods on the attrition resistance of Co F–T catalysts for SBCR use. The calcined supports had attrition resistances (inversely related to % fines <11 μm generated during attrition testing) as follows: $\text{−}\text{Al}{}_2\text{O}{}_3\text{>}\text{TiO}{}_2\text{(}\text{rutile}\text{)⪢}\text{SiO}{}_2$ Loading of Co onto the supports improved the attrition resistances of both alumina and silica significantly. It has essentially no effect on titania. The resulting catalysts had attrition resistances in the order $\text{Co}\text{/}\text{Al}{}_2\text{O}{}_3\text{>}\text{Co}\text{/}\text{SiO}{}_2\text{>}\text{Co}\text{/}\text{TiO}{}_2\text{(}\text{rutile}\text{)>⪢}\text{Co}\text{/}\text{TiO}{}_2\text{(}\text{anatase}\text{)}$ The addition of small amounts of metal (Ru, Cu) and oxide (La, Zr, K, Cr) promoters had mainly small effects on the attrition resistance of the supported Co catalysts. However, it would appear that the addition of Zr to Co/alumina had a negative impact on its attrition resistance. The different preparation methods used in this study (aqueous impregnation, non-aqueous impregnation, and kneading) did not appear to have a significant effect on catalyst attrition resistance.