Iron-based catalyst prepared by coprecipitation-melting method, preparation method and application thereof

Abstract

The application discloses an iron-based catalyst prepared by a coprecipitation-melting method. The catalyst contains iron element Fe, metal element A and metal element B. The metal element A is at least one element selected from aluminium and / or transition metal. The metal element B is at least one element selected from alkali metal and / or alkaline earth metal. Each metal element exists in the form of single metal and / or metallic oxide. With total content of metal elements contained in the catalyst being 100 wt%, the content of the metal element Fe in the catalyst is 50-99 wt%, content of the metal element A in the catalyst is 0.1-50 wt%, and content of the metal element B in the catalyst is 0.01-40 wt%. The catalyst has high activity, high mechanical stability and low reactive carbon deposition amount. Thus, pulverization of the catalyst is avoided. In addition, the catalyst shows high low-carbon olefins selectivity in the Fischer-Tropsch synthesis.

Description

technical field [0001] The application relates to an iron-based catalyst prepared by a co-precipitation-melting method, its preparation method and its application in the reaction of synthesis gas to prepare low-carbon olefins, belonging to the field of chemistry and chemical engineering. Background technique [0002] Ethylene and propylene are bulk chemical raw materials, and their industrial development level and market supply and demand balance directly affect the development level and industrial scale of the entire petrochemical industry. In view of my country's energy structure characteristics of rich coal, oil shortage, and little gas, the coal-based syngas Converting to low-carbon olefins can effectively reduce the dependence on petroleum resources. Traditionally, the preparation of olefins from syngas is mainly to convert the syngas into methanol, and then convert the methanol into light olefins (MTO). In contrast, the direct preparation of light olefins from syngas h...

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Problems solved by technology

[0003] At present, iron-based catalysts are mainly divided into bulk iron catalysts and supported iron catalysts. Supported iron catalysts have a low space-time yield due to low iron loading, which is not conducive to industrial production. Become the catalyst of choice for the direct production of light olefins from syngas

The bulk iron catalyst is mainly prepared by the co-precipitation method. When the reaction temperature of the co-precipitation iron catalyst is higher than 300 ° C, the selectivity of low-carbon olefins is higher, but the higher reaction temperature leads to a large amount of carbon deposition, and the carbon deposition causes the co-precipitation of the iron catalyst. Pulverization, reduced mechanical strength, severe blockage of catalytic bed and separation equipment in industrial applications

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