Preparation method of molecular sieve supported SCR (selective catalytic reduction) catalyst

Abstract

The invention discloses a preparation method of a molecular sieve supported SCR (selective catalytic reduction) catalyst. According to the prepared molecular sieve supported SCR catalyst, two catalytic activity units of the catalyst are designed. A first activity unit for promoting a catalytic oxidation reaction in the first step and a second activity unit which enhances the acidity of molecular sieve solids and improves the ammonia adsorption capability are designed through optimization of a molecular sieve supporting mode and components. Organic unification of the two catalytic activity units is effectively coordinated. The high-temperature hydrothermal durability of the molecular sieve catalyst is further enhanced while the catalytic activity of the molecular sieve catalyst is improved. After a high-temperature hydrothermal ageing test, 95% or higher of the catalytic activity of the catalyst can be maintained, conventional V2O5-WO3 / TiO2 oxide catalysts are almost completely inactivated, and the activity of an ordinary macroporous molecular sieve SCR catalyst can also be reduced by 50% or higher.

Description

technical field [0001] The invention belongs to the technical field of waste gas treatment, and in particular relates to a preparation method of a molecular sieve-loaded SCR catalyst. technical background [0002] Nitrogen oxides (NOx) in the atmosphere, one of the main culprits of smog, including nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrous oxide (N 2 O), etc., generally represented by NOx. Nitrogen oxides are one of the main harmful substances in the exhaust gas of boilers and internal combustion engines. Nitrogen oxides have many hazards to the environment and human health. They are toxic to the human body and are the main pollutants that form acid rain. They can form photochemical smog and is one of the greenhouse gases that destroy the ozone layer. [0003] For the purification of NOx, the current mainstream method is to use the ammonia gas (NH 3 ) and nitrogen oxides (NOx) in automobile exhaust undergo selective catalytic reduction (SCR) to generate nitroge...

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Problems solved by technology

[0004] The most commonly used NH at home and abroad 3 -SCR catalysts are mainly divided into V-W-TiO 2 based catalyst, but its catalytic activity is low at low temperature, and its hydrothermal stability is poor at high temperature, so it cannot meet the increasingly stringent emission standards

Due to the certain toxicity of vanadium-based catalysts, it obviously cannot meet the needs of use

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