CeO2-ZrO2 based SCR (selective catalytic reduction) catalyst used for denitration and preparation thereof

An SCR catalyst and a catalyst technology, which are applied in the field of nitrogen oxide post-treatment and purification, can solve the problems of poor high temperature resistance, environmental and human harm, and toxicity of the catalyst, and achieve the effects of low production cost, easy industrialization, and simple preparation process.

Active Publication Date: 2011-11-16
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, V 2 o 5 -WO 3 / TiO 2 Catalysts are widely used as commercial catalysts for denitrification of diesel vehicle exhaust and flue gas from power plants and cement plants due to their good activity and thermal stability, but V 2 o 5 It is a toxic element, which flows into nature and causes a lot of harm to the environment and human body through the enrichment of the biological chain
At the same time, V 2 o 5 -WO 3 / TiO 2 The disadvantage of poor high temperature resistance of the catalyst also limits its application in the denitrification of diesel engine exhaust

Method used

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  • CeO2-ZrO2 based SCR (selective catalytic reduction) catalyst used for denitration and preparation thereof
  • CeO2-ZrO2 based SCR (selective catalytic reduction) catalyst used for denitration and preparation thereof
  • CeO2-ZrO2 based SCR (selective catalytic reduction) catalyst used for denitration and preparation thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Take a certain amount of cerium-zirconium powder (the molar ratio of Ce to Zr is 3:1), zirconium acetate and water in a mass ratio of 40:10:50 and mix at a stirring speed of 500 rpm to prepare slurry A. Soak the 200-mesh cordierite honeycomb ceramic carrier in the solution for 10 seconds, blow out the excess solution in the channels with high-pressure gas to ensure the penetration of the honeycomb channels, and then dry the carrier at 150°C for 1 hour; repeat the above steps 3 times to obtain the loaded active component Carrier B is cerium-zirconium powder, and carrier B is calcined at 500°C for 1 hour to obtain carrier C whose active component is cerium-zirconium solid solution active coating. The loading capacity of cerium-zirconium solid solution is 100g / L, and the carrier The water absorption rate is 25wt%. Configure the required niobium oxalate (C 12 h 7 NbO 24 ) salt solution, and this solution adopts equal volume impregnation method to load Nb on the surface o...

Embodiment 2

[0037] Preparation conditions and preparation procedures are the same as Example 1, adjust Nb 2 o 5 The catalyst is prepared as 10% of the total mass of active coating + modified coating, and this SCR catalyst is marked as Nb10ZrCZ-f.

[0038] The obtained catalyst has a three-layer structure. The cordierite honeycomb ceramic is used as a carrier, an active coating is loaded on the carrier, a modified coating is loaded on the active coating, and the active coating uses cerium-zirconium solid solution as an active group. points, the modified coating is Nb 2 o 5 oxide layer.

[0039] The catalyst can be represented by the following formula, Nb 2 o 5 -ZrO 2 -Ce 0.75 Zr 0.25 o 2 , where ZrO 2 Indicates the binder used in the active coating. In the catalyst, the mass of cerium-zirconium solid solution accounts for 82.3% of the total mass of the active coating and the modified coating. ZrO 2 The mass accounts for 7.7% of the total mass of active coating and modified coati...

Embodiment 3

[0041] Preparation conditions and preparation procedures are the same as Example 1, adjust Nb 2 o 5 A catalyst was prepared for 5% of the total mass of active coating + modified coating, and this SCR catalyst was labeled as Nb5ZrCZ-f.

[0042] The obtained catalyst has a three-layer structure. The cordierite honeycomb ceramic is used as a carrier, an active coating is loaded on the carrier, a modified coating is loaded on the active coating, and the active coating uses cerium-zirconium solid solution as an active group. points, the modified coating is Nb 2 o 5 oxide layer.

[0043] The catalyst can be represented by the following formula, Nb 2 o 5 -ZrO 2 -Ce 0.75 Zr 0.25 o 2 , where ZrO 2 Indicates the binder used in the active coating. In the catalyst, the mass of cerium-zirconium solid solution accounts for 86.8% of the total mass of the active coating and the modified coating. ZrO 2 The mass accounts for 8.2% of the total mass of active coating and modified coati...

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Abstract

The invention discloses a CeO2-ZrO2 based SCR (selective catalytic reduction) catalyst used for denitration and a preparation thereof and belongs to the field of nitric oxide post-processing purification. The catalyst has a three-layer structure, wherein cordierite honeycomb ceramic is used as a carrier; an active coating is loaded on the carrier; a modifying coating is loaded on the active coating; the cordierite carrier has a skeleton carrying function; the active coating of the catalyst mainly has a function of activating NOx and NH3; and the modifying coating mainly has functions of storing NH3, avoiding deep oxidation of NH3 on the surface of the catalyst when the catalyst is used at a high temperature and increasing the sulfur poisoning resistance of the catalyst. The preparation process of the catalyst is simple and can be easily industrialized. A working temperature window of the optimized catalyst can reach 250-450 DEG C, and denitration efficiency is above 80%. The catalyst has the significant advantage of being nontoxic and has excellent heat stability and excellent SO2 poisoning resisting property.

Description

technical field [0001] The invention belongs to the field of nitrogen oxide (NOx) post-treatment purification, mainly including post-treatment denitrification of diesel vehicle exhaust, flue gas denitrification of fixed sources (thermal power plants, steel plants, garbage treatment plants and cement plants, etc.) and ship boiler exhaust gas Denitrification and other aspects; especially related to a CeO for denitrification 2 -ZrO 2 Based SCR catalyst and preparation method thereof, particularly a kind with three-layer structure, with NH 3 NO in the exhaust gas can be used as a reducing agent x Selective catalytic reduction (NH 3 -SCR) is N 2 and H 2 O CeO 2 -ZrO 2 Catalysts and methods for their preparation. Background technique [0002] Nitrogen oxides (NO x ) usually includes NO, NO 2 and N 2 O, etc., mainly come from the high-temperature combustion of motor vehicle exhaust gas, flue gas from thermal power stations, ship exhaust gas, and other industrial fossil f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/20B01D53/56B01D53/86B01D53/94
Inventor 翁端马子然司知蠢吴晓东冉锐
Owner TSINGHUA UNIV
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