A kind of preparation method of coated catalyst and catalyst

Abstract

The invention provides a method for preparing a coated catalyst. The catalyst includes a molybdenum-based compound core structure and a coated silica shell structure. The molybdenum-based compound core structure is molybdenum disulfide, molybdenum carbide and nitride One or more of molybdenum; the method includes: step A, obtaining the core structure of the powdered molybdenum-based compound; step B, mixing the powdered molybdenum-based compound with the dispersant, adding Alkali with pH value, surfactant and tetraethyl orthosilicate, solid-liquid separation after reaction, cleaning and drying the obtained solid to obtain the precursor of the coated catalyst, the precursor is roasted at 600-1000°C After obtaining the coated catalyst, the dispersant includes one or more of deionized water, ethanol and polyvinylpyrrolidone. The preparation process of the invention is simple, the raw materials are easy to obtain, the activity of microwave catalyzed direct decomposition of hydrogen sulfide is high, and the stability is good.

Description

technical field [0001] The invention belongs to the technical field of waste gas treatment containing hydrogen sulfide, and particularly relates to a preparation method of a coated catalyst and a catalyst. Background technique [0002] hydrogen sulfide (H 2 S) is a colorless and highly toxic gas with a pungent odor of rotten eggs in low concentrations, it is naturally present in crude oil, natural gas, volcanic gases, hot springs and some lakes, and also comes from by-products of industrial manufacturing, Such as petroleum refining, natural gas purification, coal mining, paper mills, leather factories, etc. It will not only cause serious corrosion to the transportation pipeline, but also bring a huge burden to the environment, and also pose a serious threat to human health. Therefore, in the treatment of hydrogen sulfide, national regulations also put forward strict requirements on related industries. [0003] At present, the main method of industrially treating hydrogen ...

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Problems solved by technology

[0003] At present, the main method for industrially treating hydrogen sulfide waste gas is the Claus process, which is to incompletely oxidize hydrogen sulfide to generate water and sulfur, so that sulfur can be recovered, but hydrogen resources are wasted, because hydrogen sulfide waste gas cannot be recovered It is completely oxidized, and the tail gas is also accompanied by the generation of sulfur dioxide. Direct discharge into the atmosphere will cause secondary pollution. Therefore, it is very meaningful to find an effective way to directly decompose hydrogen sulfide into sulfur and hydrogen.

[0004] In recent years, there are many shortcomings in the method of directly decomposing hydrogen sulfide to generate hydrogen and sulfur: excessive energy consumption, expensive materials, low catalyst decomposition efficiency and easy deactivation, harsh decomposition reaction conditions, etc., for example: Furhad et al. Directly decompose hydrogen sulfide without adding a catalyst. It is found that the conversion rate of hydrogen sulfide is 35.6% at a temperature of 1200°C and a pressure of 0.1Mpa. The rate can reach 65.8%. Although this process realizes the direct decomposition of hydrogen sulfide, the required temperature is too high and consumes a lot of energy; Zhao et al. used pulsed corona discharge plasma reactor to explore the direct decomposition of hydrogen The minimum energy consumption of each hydrogen sulfide molecule is 17 eV, but it cannot handle the high concentration of hydrogen sulfide gas, which also limits the industrial application; Ma Guijun et al. 2+ When doped into ZnS, the decomposition rate of hydrogen sulfide can reach 17 μmol / h, but the catalyst is easily deactivated, the utilization rate of visible light is extremely low, and the decomposition efficiency is not high

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