Storage reduction catalyst used for removing nitrogen oxide in lean burn engine tail gas and preparation method

A nitrogen oxide and engine technology, which is applied in the field of nitrogen oxide storage and reduction catalyst and preparation, can solve the problems of anti-sulfur poisoning, narrow active temperature window, poor hydrothermal aging ability, etc., and achieves convenient operation, low cost, and easy preparation process simple effect

Active Publication Date: 2011-09-07
CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main problems of nitrogen oxide storage and reduction catalysts include: narrow activity temperature window, resistance to sulfur poisoning, poor hydrothermal aging ability, etc.
[0005] At present, there are no domestic patents on the preparation method of nitrogen oxide storage and reduction catalysts. Therefore, it is particularly necessary to develop a catalyst preparation method with a wide active temperature window and strong resistance to sulfur poisoning and hydrothermal aging.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Take 30.38g of cerous nitrate and 9.63g of zirconium nitrate and dissolve them in 100mL of deionized water, the molar ratio Ce:Zr=7:3, the molar concentration is [Ce+Zr]=1mol / L, use 3mol / LNH under rapid stirring 3 ·H 2 O for precipitation, adjust the pH value to 7, add 0.5 g of polyethylene glycol, fully stir for 30 min, let stand at room temperature for 1 h, and age at 80 ° C for 3 h; vacuum filter to obtain the precipitate, and use deionized water to wash the precipitate until The filtrate is neutral, and then the resulting filter cake is dried at 120°C for 12 hours, pre-calcined at 300°C for 1 hour, and roasted at 500°C for 3 hours to obtain cerium-zirconium powder Ce 0.7 Zr 0.3 o 2 .

[0032] Measured cerium zirconium powder Ce 0.7 Zr 0.3 o 2 The water absorption rate is 0.5mL / g.

[0033] Weigh 6.6776g Ba(CH 3 COO) 2 Dissolve in 10ml of water, load on the cerium-zirconium carrier by equal volume impregnation method, dry in the shade at room temperature, dry...

Embodiment 2

[0038] Take 12.12g of cerium sulfate and 6.42g of zirconium oxynitrate and dissolve them in 50mL of deionized water, the molar ratio Ce:Zr=6:4, the molar concentration is [Ce+Zr]=1mol / L, use 4mol / LNH under rapid stirring 3 ·H 2 O for precipitation, adjust the pH value to 9, add 0.15 g of polyethylene glycol, fully stir for 30 min, let stand at room temperature for 1 h, and age at 80 ° C for 3 h; vacuum filter to obtain the precipitate, and use deionized water to wash the precipitate until The filtrate is neutral, and then the resulting filter cake is dried at 120°C for 12 hours, pre-calcined at 300°C for 1 hour, and roasted at 500°C for 3 hours to obtain cerium-zirconium powder Ce 0.6 Zr 0.4 o 2 .

[0039] Measured cerium zirconium powder Ce 0.6 Zr 0.4 o 2 The water absorption rate is 1.2mL / g. Weigh 10.44g Ba(NO 3 ) 2 Dissolve in 10ml of water, load on the cerium-zirconium carrier by equal volume impregnation method, dry in the shade at room temperature, dry at 120°C ...

Embodiment 3

[0044] Take 14.92g of cerous chloride and 3.22g of zirconium chloride and dissolve them in 50mL of deionized water, the molar ratio Ce:Zr=8:2, the molar concentration is [Ce+Zr]=1mol / L, use 4mol / LNH under rapid stirring 4 HCO 3 Precipitate, adjust the pH value to 11, add 0.3g of polyethylene glycol, stir thoroughly for 30min, let stand at room temperature for 1h, and age at 80°C for 3h; vacuum filter to obtain the precipitate, and use deionized water to wash the precipitate to the filtrate It is neutral, and then the obtained filter cake is dried at 120°C for 12 hours, pre-calcined at 300°C for 1 hour, and fired at 500°C for 3 hours to obtain cerium-zirconium powder Ce 0.8 Zr 0.2 o 2 .

[0045] Measured cerium zirconium powder Ce 0.8 Zr 0.2 o 2 The water absorption rate is 1.0mL / g. Weigh 13.36g Ba(CH 3 COO) 2 Dissolve in 10ml of water, load on the cerium-zirconium carrier by equal volume impregnation method, dry in the shade at room temperature, dry at 120°C for 0.5-3...

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Abstract

The invention relates to a storage reduction catalyst used for removing nitrogen oxide in lean burn engine tail gas and a preparation method. The preparation method comprises the following steps of: with soluble cerium salt and zirconium salt as raw materials, alkali as coprecipitator and polyethylene glycol as thickening agent, preparing a cerium zirconium powder carrier according to the atom ratio of Ce to Zr of (6-8):(4-2); with soluble barium salt as a raw material, loading the barium salt onto the cerium zirconium powder carrier by adopting an isovolumetric method, wherein BaO accounts for 20-40% of the mass of the catalyst; then loading one or two precious metals of Pt and Pd accounting for 1.0-3.0% of the mass of the catalyst by adopting the isovolumetric method, thus a sample I isobtained; with Al2O3 as a carrier, loading one or two precious metals of Rh and Pd accounting for 0.5-2.0% of the mass of the catalyst by adopting the isovolumetric method, thus a sample II is obtained; and mechanically mixing the sample I and the sample II according to the mass ratio of (1-3):1, thus the nitrogen oxide storage reduction catalyst comprising 50-75% of ((Pt,Pd) / BaO / CexZr(1-x)O2) and 50-25% of ((Rh,Pd) / Al2O3) is obtained, wherein NOx conversion rate of the catalyst can reach more than 80%. After treatment in presence of high-temperature water vapour or SO2 is carried out, the nitrogen oxide storage reduction activity is maintained to be more than 80%.

Description

technical field [0001] The invention relates to a nitrogen oxide storage and reduction catalyst for removing lean-burn engine exhaust gas and a preparation method thereof, more specifically, to a nitrogen oxide storage and reduction catalyst for removing lean-burn engine exhaust gas and its preparation method. Preparation. Background technique [0002] According to statistics, in 2010 China's auto production and sales exceeded 18 million. With the continuous development of the economic level, the production and sales of automobiles will maintain a continuous growth momentum. The rapid development of the automobile industry has also brought problems of energy shortage and environmental pollution. Against this backdrop, lean-burn technology emerged as the times require. Lean combustion technology is an effective measure to reduce vehicle exhaust emissions and reduce fuel consumption. The air-fuel ratio of a lean-burn engine works stably is 23-27, and the oxygen concentrati...

Claims

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Application Information

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IPC IPC(8): B01J23/58B01D53/94B01D53/56
Inventor 王建强王远高继东马杰刘双喜沈美庆
Owner CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD
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