Diesel vehicle exhaust purification SCR (Selective Catalytic Reduction) catalyst and preparation method thereof

A technology for SCR catalyst and tail gas purification, which is applied in the direction of physical/chemical process catalysts, chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, etc., and can solve the problems of poor reproducibility of thermally stable catalyst preparation methods, etc. , to achieve excellent high-temperature activity and hydrothermal stability, good stability, and wide activity temperature window

Active Publication Date: 2014-05-07
DONGFENG COMML VEHICLE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the thermal stability of the catalyst existing in the prior art and the problem of poor reproducibility of the catalyst preparation method, and to provide a diesel vehicle exhaust purification SCR with good thermal stability and reproducibility Catalyst and its preparation method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0044] A preparation method of the above-mentioned diesel vehicle exhaust purification SCR catalyst, the preparation method comprises the following steps in sequence:

[0045] Step 1: First configure an oxalic acid solution with a mass percentage concentration of 5%, then completely dissolve ammonium tungstate in the oxalic acid solution, then add titanium dioxide / silicon dioxide composite oxide powder and stir evenly to obtain a mixed system, and then The mixed system is sequentially dried and calcined to obtain TiO 2 -SiO 2 / WO 3 Powder, wherein the mass ratio of ammonium tungstate to titanium dioxide / silicon dioxide composite oxide powder is 12 to 18:100;

[0046] Step 2: First configure an oxalic acid solution with a mass percent concentration of 5%, then completely dissolve ammonium metavanadate into the oxalic acid solution, and then add the above-mentioned TiO 2 -SiO 2 / WO 3 Mix the powder evenly to form a mixed slurry with a solid-to-liquid ratio of 25% to 45%, th...

Embodiment 1

[0062] A diesel vehicle exhaust gas purification SCR catalyst, the catalyst includes a cordierite honeycomb ceramic carrier and a coating loaded on the cordierite honeycomb ceramic carrier, the raw material composition of the coating includes titanium dioxide / silicon dioxide composite oxide powder, tungsten ammonium metavanadate, ammonium metavanadate, and auxiliary materials, wherein the mass ratio of the titanium dioxide / silicon dioxide composite oxide powder, ammonium tungstate, and ammonium metavanadate is 100:12:3, and the titanium dioxide / silicon dioxide Composite oxide powder is prepared by co-precipitation method, it is single anatase type, and its specific surface area is 120-200m 2 / g, the particle size is 20-50nm, the density of the cordierite honeycomb ceramic carrier is 400 mesh / square inch, and its coefficient of thermal expansion is less than 1.85×10 -6 / °C.

[0063] A preparation method of the above-mentioned diesel vehicle exhaust purification SCR catalyst, t...

Embodiment 2

[0069] The steps are the same as in Example 1, except that the mass ratio of the titanium dioxide / silicon dioxide composite oxide powder, ammonium tungstate, and ammonium metavanadate is 100:16:4, and in step two, the triethanolamine, The mass ratio of silica sol is 1:2.

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Abstract

The invention discloses a diesel vehicle exhaust purification SCR (Selective Catalytic Reduction) catalyst. The catalyst comprises a cordierite honeycomb ceramic carrier and a coating which is loaded on the cordierite honeycomb ceramic carrier; the coating comprises the following raw materials: titanium dioxide/silicon dioxide composite oxide powder, ammonium tungstate and ammonium metavanadate according to a mass ratio of 100:(12-18):(3-6). A preparation method of the catalyst comprises the steps of mixing the ammonium tungstate with the titanium dioxide/silicon dioxide composite oxide powder firstly to prepare TiO2-SiO2/WO3 pccowder, then mixing the ammonium metavanadate with TiO2-SiO2/WO3 to prepare slurry to be coated, and then coating the cordierite honeycomb ceramic carrier with the slurry to be coated by using an impregnation method. The catalyst is wide in activity temperature window, high in high-temperature activity and water/heat resistant stability, and good in reproducibility.

Description

technical field [0001] The invention belongs to the field of diesel vehicle exhaust purification, and in particular relates to a diesel vehicle exhaust purification SCR catalyst and a preparation method thereof, which are particularly suitable for obtaining a wider activity temperature window, better high-temperature activity and hydrothermal resistance stability. Background technique [0002] At present, selective catalytic reduction technology (SCR) is considered to be a method to effectively purify NOx in diesel vehicle exhaust under oxygen-enriched conditions. The basic principle is to use NH 3 Reduction, under the action of catalyst, NH 3 Selectively reduce NOx under oxygen-enriched conditions to harmless and non-toxic N 2 and H 2 O, to achieve NOx purification, the key to this technology is the use of high-performance catalysts. [0003] TiO, one of the research hotspots of domestic diesel vehicle exhaust purification SCR catalysts 2 -V 2 o 5 -WO 3 The catalytic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/30
Inventor 王健易俊霞
Owner DONGFENG COMML VEHICLE CO LTD
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