Catalyst and preparation method thereof

Abstract

The invention provides a catalyst and a preparation method thereof, wherein the catalyst comprises the following compositions in percentage by mass: 20 to 60% of Fe2O3, 20 to 60% of MnO2, 9.7 to 30% of Mn2O3, and 6 to 30% of Mn3O4; and the method for preparing the catalyst comprises the following steps of: adding a polyethylene glycol aqueous solution into a bivalent manganese salt aqueous solution at a certain temperature, then adding potassium permanganates and a ferric salt aqueous solution into the obtained mixed solution; stirring the obtained mixture so as to obtain a precipitate; filtering the obtained object so as to obtain a solid as the precursor of the catalyst; drying and then roasting the solid; and crushing the obtained solid subjected to roasting into particles so as to obtain the catalyst. The catalyst and the preparation method provided by the invention have the advantages that by using the prepared catalyst, at a reaction temperature of 100 DEG C, the rate of conversion between NO in tail gas and NO2 can achieve 91%; the prepared catalyst is larger in specific surface area and pore volume, and high in catalytic oxidation efficiency; and the prepared catalyst has a low-temperature catalytic activity, and can be used in the removal of NO in low-temperature oxygen-containing exhaust emission sources without performing the removal at a high temperature and addingoxidants, thereby saving energy and reducing consumption and cost.

Description

technical field [0001] The invention relates to a catalyst and a preparation method thereof, belonging to the technical field of air pollution purification. Background technique [0002] Nitrogen oxides (NO x ) is one of the main air pollutants, mainly causing environmental hazards of photochemical smog, acid rain and greenhouse effect. Global NO now x The emissions have reached 35-58 Mt / a, more than 95% of which come from the combustion process of fossil fuels. NO emission accounted for NO in combustion flue gas x 90%~95% of the total emissions. At present, ammonia selective catalytic reduction method is mostly used in the world to purify NO in fixed source waste gas; for industrial waste gas from nitric acid plant, the conventional method is liquid absorption, but this method is only suitable for NO 2 High content of exhaust gas. For industrial waste gas with high NO content, the oxidation-absorption method is usually required: since NO is insoluble in water and lye,...

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Problems solved by technology

[0004] In order to solve the low catalytic efficiency and the difficulty of oxidation of NO to NO at low temperature 2 etc., the present invention provides a catalyst based on the patent CN200710065784.6 to further improve the low-temperature activity of the catalyst system (<150°C), so that it can be used in the flue gas process after desulfurization and dust removal in coal-fired power plants

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