Catalyst for preparing nitric oxides through catalytic ammonia oxidation

Abstract

The invention discloses a preparation method of a supported catalyst for preparing nitric oxides through ammonia oxidation. A photocatalyst serves as a catalyst carrier in the ammonia oxidation process, nitrate of metal platinum, rhodium or palladium or a chlorine-containing compound serves as a precursor, the metal platinum, rhodium or palladium or alloys thereof are supported on the catalyst carrier to serve as active ingredients by utilizing photocatalysis properties of titanium dioxide or zirconium dioxide or tungsten oxide or molybdenum oxide through a photocatalytic reduction deposition or photocatalytic reduction codeposition method under ultraviolet light or visible light irradiation, and the catalyst is applied to the catalytic ammonia oxidation process. The obtained supported catalyst is large in specific surface area, low in metal load capacity, low in reaction temperature and high in activity, the amount of precious metals in the ammonia oxidation process can be effectively reduced, and the cost of the catalyst is reduced.

Description

Technical field [0001] The present invention involves the preparation of a load catalyst for nitrogen oxides to catalyze the ammonia oxidation process, especially for the preparation of load catalysts used in the ammonia oxidation process in the nitrate industry. Background technique [0002] my country is a large country for nitric acid. In 2009, the production capacity of more than 9.67 million tons, ranking first in global production capacity.As a basic chemical raw material, nitric acid occupies an important position in the national economy. Its production process uses the ammonia oxidation method, and precious metal platinum is used as a catalyst. [0003] 4NH 3 +5O 2 = 4NO + 6H 2 O ΔH = -907.28 KJ [0004] At present, the ammonia oxidation process of the nitrate industry is based on platinum or platinum 钯 铑 目前 目前 目前 目前. Among them, large -scale oxide furnaces are mainly used for insulation reactions. The operating temperature is 780 ~ 940 ° C, and the working pressure is 0....

AI Technical Summary

Problems solved by technology

[0011] 1: The catalyst surface utilization rate is low, and the space velocity of ammonia and air entering the oxidation furnace is 90000h -1 , the time for the mixed gas to stay is very short: the free area of ​​the platinum mesh accounts for more than 50%, which will cause the mixed gas to pass directly through the gap, and the area on the other side of the platinum mesh catalyst is not well utilized.

[0012] 2: Poor mechanical strength of platinum mesh catalyst

[0025] The preparation methods of supported catalysts usually include impregnation method, co-precipitation method, electroplating method, coating method, etc., but it is difficult to control the loading amount of the above-mentioned traditional methods of loading catalysts, especially it is difficult to precisely control the loading process to obtain highly dispersed single-atom active components. layer supported catalyst

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