Dysprosium-modified Cu-SAPO-34 molecular sieve denitration catalyst and preparation method thereof

Abstract

The invention discloses a dysprosium-modified Cu-SAPO-34 molecular sieve denitration catalyst and a preparation method thereof. The preparation method comprises the steps that: 1, weighing an aluminumsource, a silicon source, phosphoric acid, a template agent, copper nitrate, dysprosium nitrate and deionized water, and preparing a homogeneous aqueous solution A; 2, carrying out a hydrothermal reaction on the aqueous solution A obtained in the step 1, and aging the reaction product at 160-200 DEG C to obtain a reaction product B; and 3, washing and drying the reaction product B obtained in thestep 2, and calcining the reaction product B at the temperature of 450 DEG C or above to obtain the dysprosium-modified Cu-SAPO-34 molecular sieve denitration catalyst. The preparation method disclosed by the invention can be used for preparing the dysprosium modified Cu-SAPO-34 molecular sieve denitration catalyst disclosed by the invention; the dysprosium-modified Cu-SAPO-34 molecular sieve denitration catalyst provided by the invention can be used for selective catalytic reduction removal of nitrogen oxides in diesel vehicle tail gas, and has certain sulfur dioxide poisoning resistance andgood low-temperature catalytic performance.

Description

technical field [0001] The invention belongs to the technical field of environmental catalysis and the technical field of molecular sieve catalysts, and relates to a modified Cu-SAPO-34 molecular sieve denitration catalyst, in particular to a dysprosium-modified Cu-SAPO-34 molecular sieve denitration catalyst and a preparation method thereof. Background technique [0002] In recent years, my country has faced severe environmental problems, among which smog is one of the most serious environmental pollution; nitrogen oxides (NO x ) is one of the main components in the composition of smog. NO x The harm is extremely serious. In addition to causing smog problems, it will also cause environmental problems such as acid rain, photochemical smog, and ozone layer destruction. NO x There are two major sources of generation, one is generated by fixed source devices represented by power plants; the other is generated by mobile source devices represented by diesel vehicles. Among th...

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Problems solved by technology

The preparation method is a two-step ion exchange method, the synthesized H-SAPO-34 molecular sieve is first exchanged into NH 4 -SAPO-34, and then converted to Cu-SAPO-34 by ion exchange, the synthesis process is cumbersome

At the same time, when the quality of diesel is poor, in addition to NO x In addition, it also contains a small amount of sulfur dioxide (SO 2 ), while SO 2 Can lead to copper-based SAPO-34 catalyst poisoning, thereby reducing its catalytic reduction of NO x Ability

At the same time, the research on the exhaust of diesel vehicles in real life found that although the internal temperature of the diesel engine is as high as 1800°C, the average temperature of the exhaust gas is concentrated at 150-350°C, especially when the diesel vehicle is cold-started, the exhaust temperature will remain low for a long time At 200°C, while the current commercial copper-based SAPO-34 molecular sieve catalysts have low catalytic activity at lower temperatures (200°C), resulting in more NO x emissions

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