Shell distributed catalyst and application thereof

Abstract

The invention provides a shell distributed catalyst and an application thereof. The catalyst is prepared and obtained according to the following steps: soaking a carrier in a first solution containing assistant compounds, drying, and controlling the soaking condition and the type of the first solution to allow the assistant compounds to distribute on the carrier in a shell manner so as to obtain the carrier carrying the assistant compounds; soaking the carrier carrying the assistant compounds in a second solution containing active compounds, drying, and controlling the soaking condition and the type of the second solution to allow the active compounds to distribute on the carrier in the shell manner so as to obtain a catalyst carrying the assistant compounds and the active compounds. The catalyst provided by the invention is firm in homonuclear combination of shell, long-periodic stability of structural distribution can be kept, and the catalyst is applied to F-T synthetic reaction and is higher in activity and good in stability; the activity and structure of the catalyst remain unchanged basically after long-time operation.

Description

technical field [0001] The invention relates to a shell-layer distributed catalyst and its application in Fischer-Tropsch synthesis reaction. Background technique [0002] For a gas-solid-liquid multiphase reaction system such as Fischer-Tropsch synthesis in a fixed-bed reactor, the particle size of the catalyst is generally required to be several millimeters. Therefore, the influence of diffusion control on the activity of the catalyst is unavoidable. And it has been noticed that the heavy paraffin wax synthesized by FT is usually attached to the surface of the catalyst in the form of liquid, aerosol or slurry, thus affecting the reactant H 2 and the diffusion of CO inside the catalyst particles. During the internal diffusion of reactants, H 2 The diffusion rate of CO is faster than that of CO, therefore, the diffusion limitation of CO in the catalyst particles is obviously stronger than that of H 2 , and due to the different particle sizes, the CO concentration gradient...

AI Technical Summary

Problems solved by technology

During the internal diffusion of reactants, H 2 The diffusion rate of CO is faster than that of CO, therefore, the diffusion limitation of CO in the catalyst particles is obviously stronger than that of H 2 , and due to the different particle sizes, the CO concentration gradient inside the particles is different, which affects the combination of CO and the metal active center, which increases the H / C ratio adsorbed on the active center and reduces the probability of carbon chain growth. This reduces the C 5 + selectivity

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