Supported catalyst for preparing NOx through ammonia low-temperature catalytic oxidization, preparation and application thereof

Abstract

The invention relates to preparation of a supported catalyst for preparing NOx through ammonia low-temperature catalytic oxidization. The supported catalyst is used in an ammonia oxidization process in nitric acid industry. The catalyst is prepared by supporting an active component, Pt, on manganese oxide in an impregnation manner, wherein the MnOx, as the supporter, can increase active sites of the Pt, so that the ammonia gas can be completely converted into the NOx just at 400 DEG C. The supported catalyst greatly reduces reaction energy consumption and has good market application prospect. The catalyst supported by MnOx has low reaction temperature and high activity, effectively reduces the use quantity of noble metal in ammonia oxidization and is reduced in cost.

Description

technical field [0001] The invention relates to the preparation of a supported catalyst for preparing nitrogen oxides by catalytic oxidation of ammonia at low temperature, which is used in the ammonia oxidation process in the nitric acid industry to reduce the consumption of precious metals. Background technique [0002] my country is a big country in the production of nitric acid, ranking first in the world in production capacity. As a basic chemical raw material, nitric acid occupies an important position in the national economy, and its production process adopts the ammonia oxidation method. At present, the ammonium oxidation process in the nitric acid industry uses platinum or platinum-palladium-rhodium alloy wire mesh as a catalyst, and a large-scale oxidation furnace is mainly used for adiabatic reaction. The working temperature is 780~940°C and the working pressure is 0.1~1.0MPa. The performance advantages of the platinum mesh catalyst mainly show: high selectivity f...

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Problems solved by technology

[0005] The ammonia oxidation process is a high temperature process, and the reaction temperature is generally 800-900 o C, at this temperature, volatile platinum oxide is generated and taken away by the air flow, resulting in the loss of platinum

The mechanical loss of platinum caused by air scour is another cause of platinum consumption

[0006] Because the reaction is an adiabatic reaction, when the air distribution is uneven, the temperature rise exceeds 880°C, or side reactions occur during ignition or pulse feeding: 4NH3 + 6NO = 5N2 + 6H2O ΔH= -1810.79 kJ Transient high-heat reaction occurs to generate a lot of heat , will cause a sharp increase in platinum consumption

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