Preparation process of selective reduction catalyst for lean-burn gasoline motor car exhausted gas nitrogen oxide

A technology for tail gas emission and nitrogen oxides, which is applied in catalyst activation/preparation, metal/metal oxide/metal hydroxide catalyst, physical/chemical process catalyst, etc. It can solve the problem of not many research reports and achieve high catalytic performance. Conversion efficiency, control of lean-burn vehicle exhaust emissions, and the effect of good environmental benefits

Inactive Publication Date: 2006-04-26
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, Ag / Al 2 o 3 In-depth basic theoretical research has been carried out on catalysts, but there are not many research reports on how to optimize the monolithic catalyst preparation process to improve the NOx reduction performance of this catalyst

Method used

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  • Preparation process of selective reduction catalyst for lean-burn gasoline motor car exhausted gas nitrogen oxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Add dilute HNO to pseudoboehmite dry rubber powder 3and urea, and after stirring at high speed for 5 hours, an alumina sol with a solid content of 21 wt % was obtained. Immerse the 400-hole cordierite honeycomb ceramic monolith sample in the above sol for 1 minute, blow off the excess sol in the carrier channel with compressed air after taking it out, then place the carrier sample at room temperature to dry in the shade (32°C) for 6 hours, and put it in an oven at 110°C. °C for 6 hours, and finally baked in a muffle furnace at 600 °C for 2 hours to prepare a ceramic carrier with activated alumina coating.

[0023] The above-mentioned ceramic carrier with alumina coating is impregnated with a certain concentration of silver nitrate aqueous solution in an equal volume, then dried in an oven at 110 ° C, and finally roasted in a muffle furnace at 600 ° C for 3 hours to obtain Ag / Al 2 o 3 Monolithic catalyst with 2 wt% Ag loading.

Embodiment 2

[0025] A certain concentration of silver nitrate aqueous solution is impregnated with the ceramic support with alumina coating prepared in Example 1 in the following excessive impregnation mode: according to the saturated water absorption of the alumina coating on the honeycomb ceramic support and Loading capacity, calculate the concentration of silver nitrate solution, prepare the corresponding silver nitrate solution, the coated Al 2 o 3 The coated carrier is immersed in the silver nitrate solution prepared above for 30-120 minutes, and then the carrier is taken out, and the excess silver nitrate solution remaining in the pores of the catalyst carrier is blown out with compressed air. Then the catalyst was heated and dried in an oven at 110°C, and finally calcined in a muffle furnace at 600°C for 3 hours to obtain Ag / Al 2 o 3 Monolithic catalyst with 2 wt% Ag loading.

Embodiment 3

[0027] The ceramic carrier with alumina coating prepared in Example 1 was impregnated with a silver nitrate aqueous solution of a certain concentration in the excessive impregnation method described in Example 2, then dried by microwave for 10 minutes, and finally calcined in a muffle furnace at 600 ° C for 3 hours to obtain Ag / Al 2 o 3 Monolithic catalyst with 2 wt% Ag loading.

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PUM

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Abstract

The preparation method for catalyst to selective reduce nitrogen oxide in tail gas from gasoline vehicle comprises: with quasi-thin diaspore dry powder as material, nitric acid as peptizer and urea as dispersant, grinding to obtain aluminum solution; dipping the 200-800 pores/inch2 cordierite honeycomb ceramic carrier into said solution, taking out to dry and form Al2O3 coat; excessive immersing into silver nitrate solution, taking out to calcine and obtain the product. This catalyst has high catalytic conversion rate to NOx special at low temperature, solves the difficulty that it is hard to remove NOx on oxygen-enriched condition, and has well environmental benefit.

Description

technical field [0001] The invention relates to a preparation method of a nitrogen oxide selective reduction catalyst for lean-burn gasoline vehicle tail gas emission, and belongs to the technical field of preparation of nitrogen oxide reduction catalysts in environmental protection. Background technique [0002] With the global energy crisis and the increasing effect of greenhouse gases, how to improve fuel economy and reduce CO 2 Emissions of greenhouse gases such as greenhouse gas emissions have become an energy and environmental issue of widespread concern around the world. At present, the commonly used gasoline engine works near the theoretical air-fuel ratio, so that the three-way catalyst installed in the exhaust aftertreatment system of gasoline vehicles can efficiently convert CO, HC and NOx in the exhaust gas of the engine into harmless CO 2 、H 2 O and N 2 , but the above-mentioned simultaneous and efficient conversion mechanism of several pollutants is based on...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/50B01D53/94B01J37/025
CPCY02T10/12
Inventor 康守方李俊华傅立新
Owner TSINGHUA UNIV
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