Low-temperature catalyst and preparation method thereof

Abstract

The invention discloses a low-temperature catalyst. The low-temperature catalyst comprises one or more lanthanide series metal oxides and/or one or more transition metal oxides and/or one or more alkali or alkaline earth metal oxides, and also comprises copper and iron molecular sieve catalysts. The one or more lanthanide series metal oxides are selected from La, Ce, Zr and Nb oxides and have a use ratio of 1-50wt%. The one or more transition metal oxides are selected from Fe, Co, Ni, Cu, Mn, Zn, V, W, Mo and Ti oxides and have a use ratio of 1-50wt%. The one or more alkali or alkaline earth metal oxides are selected from Li, K, Cs, Ba, Sr and Ca oxides and have a use ratio of 1-30wt%. The copper and iron molecular sieve catalysts comprise aluminosilicate zeolite and/or aluminum phosphate molecular sieves. Through loading the one or more composite oxides on the copper and iron molecular sieve catalysts, the oxidizing agent for oxidizing NO into NO2 is obtained and reaction activity of whole SCR is improved.

Description

technical field [0001] The invention relates to a molecular sieve catalyst using composite oxide as ion exchange, especially a catalyst with high activity at low temperature and a preparation method thereof. Background technique [0002] Nitrogen oxides (N y o x ) mainly includes N 2 O, NO, N 2 o 3 , NO 2 , N 2 o 4 , N 2 o 5 and other compounds are the main air pollutants, and the N emitted into the atmosphere around the world every year y o x The total amount reaches 50 million tons, and it is still growing. Therefore study governance N y o x It is one of the main contents in the field of global environmental protection. [0003] N y o x There are two ways of production: one is natural production, and the other is artificial production. Naturally produced sources include lightning, ammonia oxidation in the atmosphere, and nitrification by microorganisms in the soil, etc. N y o x Due to the natural selection to achieve ecological balance, there is no great...

AI Technical Summary

Problems solved by technology

[0014] Although SCR technology has been industrialized and has some advantages, it still has some disadvantages, such as short catalyst life, low activity of traditional vanadium-based catalysts, high sulfur dioxide oxidation activity, and a lot of sulfate formation. Causes catalyst deactivation and clogs downstream piping

Therefore, it is necessary to put the catalyst after the desulfurization and dust removal equipment, so that the life of the catalyst will be greatly increased; however, generally speaking, after the desulfurization and dust removal equipment, the temperature of the exhaust gas is reduced to below 200 degrees Celsius, and the traditional vanadium-titanium catalyst less active

In recent years, copper and iron molecular sieve catalysts have been found to have high catalytic activity and nitrogen selectivity, but the low-temperature activity of the catalyst is also low, especially when the temperature of the exhaust gas is below 200 degrees Celsius

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