Porous carbon-loaded cobalt-based Fischer-Tropsch synthesis catalyst containing silicon dioxide auxiliary agent and preparation method thereof

Abstract

The invention discloses a porous carbon-loaded cobalt-based Fischer-Tropsch synthesis catalyst containing a silicon dioxide auxiliary agent and a preparation method thereof. The catalyst uses cobalt as an active component, silicon dioxide as the auxiliary agent and porous carbon as a carrier, and the mass percentages of cobalt and silicon dioxide are 25.8 to 30.6% and 6.2 to 21.0% respectively, with the balance being the porous carbon carrier. Metallic cobalt particles are uniformly distributed on the catalyst and densely arrayed; the diameters of the particles are in a range of 6 to 9 nm; and the silicon dioxide auxiliary agent exists on the surfaces of the particles. According to the invention, a CO-MOF-71 metal-organic framework is used as a sacrificial template, a silicon source is doped by using an impregnation method, and then the silicon dioxide-supported porous carbon-loaded cobalt-based catalyst is prepared on a fixed bed through one-step in-situ pyrolysis method. The catalyst prepared in the invention has high specific active site density; and when applied to Fischer-Tropsch synthesis, the catalyst has good C<5+> selectivity, especially high C<5+> space-time yield, on the basis of high activity.

Description

technical field [0001] The invention relates to a cobalt-based Fischer-Tropsch synthesis catalyst, its preparation method and application, in particular to a highly active cobalt-based Fischer-Tropsch synthesis catalyst, its preparation method and application. Background technique [0002] Fischer-Tropsch synthesis refers to the process of hydrogenation of carbon monoxide to generate hydrocarbons and oxygenated compounds. Its main application is to use synthesis gas as raw material to produce chemical products such as gasoline, diesel oil, wax, and liquefied petroleum gas. The product has the characteristics of no sulfur and nitrogen. It is a key step in the indirect conversion of non-petroleum resources such as coal, natural gas or biomass into liquid fuels or chemicals, and has attracted much attention for many years. [0003] Since the Fischer-Tropsch synthesis technology came out in the 1920s, researchers have conducted extensive research on the types of catalysts. A la...

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Problems solved by technology

Compared with catalysts based on alumina or silica, cobalt catalysts based on carbon materials have better high-temperature properties, acid and alkali resistance, and better specific surface area. The force is weak, and the cobalt particles are prone to agglomeration behavior during the pretreatment or reaction process and do not meet the optimal size range

Although the preparation methods, compositions and structures of the catalysts reported in each patent and literature are different, and the optimal reaction conditions are also different, the final reaction effect is not particularly remarkable, especially the catalyst activity and the space-time yield of the liquid product are not high. This is mainly due to the unsatisfactory comprehensive factors such as catalyst loading, reduction degree, dispersion, active site particle size, and specific active site density.

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