Combined catalyst for improving denitration performance and application thereof

Abstract

The invention discloses a combined catalyst for improving denitration performance and an application thereof, which belongs to the field of catalysts. In the catalyst, industrial anatase crystal form TiO2 is taken as a carrier; V2O5-WO3 / TiO2 is put at the front section of MnOx-CeO2 / TiO2, and is called front section; MnOx-CeO2 / TiO2 is called back section; the front section refers to a section where an air current main body is contacted firstly; the back section refers to a section where the air current main body is contacted secondly; the mass ratio of the front section to the back section is 1:1-1:3; V2O5 accounts for 2-4 percent of the mass of the carrier TiO2; WO3 accounts for 8-10 percent of the mass of the carrier TiO2; Mn accounts for 10-20 percent of the mass of the carrier TiO2; CeO2 accounts for 8-10 percent of the mass of the carrier TiO2; and MnOx is taken as the general name of MnO2 and Mn2O3. The combined catalyst can be applied to an integral catalyst for industrial application. The combined catalyst has a wider active temperature window; particularly, the removing efficiency of NOx by NH3-SCR is greatly increased under the exhaust low-temperature wording condition of a diesel engine; and moreover, the same NOx removing efficiency as the conventional catalyst can be obtained at a medium-high temperature section.

Description

technical field [0001] The invention belongs to a catalyst segmented combination method for improving the performance of ammonia selective catalytic reduction of nitrogen oxides in diesel engine exhaust purification, in particular to a segmented combination method for improving the load-type composite oxide catalyst and the load The catalytic performance of the type monolithic catalyst can pass NH 3 A method for selective catalytic reduction of nitrogen oxides. Background technique [0002] Since the 1970s, with the aggravation of the shortage of global oil resources, the intensification of the greenhouse effect and the CO 2 The increase in emission reduction pressure and the continuous improvement of diesel engine technology make modern diesel engines not only efficient, economical (fuel consumption is about 30% lower than gasoline engines), environmentally friendly (CO 2 Its emissions are about 30% lower than that of gasoline engines), and it is completely comparable to ...

AI Technical Summary

Problems solved by technology

For example, the denitrification methods disclosed in patent CN101428215 and patent CN101396655 are based on V 2 o 5 -WO 3 / TiO 2 The advantage of this type of catalytic system is that it has a high catalytic activity for the standard SCR reaction shown in equation (1), but it also has certain problems: the use temperature range of the catalyst is limited to 250-430 °C , has the characteristics of high operating temperature and narrow temperature window, and the catalyst has poor activity below 250 °C, so there is a lot of gas preheating energy consumption in industrial applications, although increasing the V in the catalyst 2 o 5 The specific gravity can also improve the low-temperature activity, but at the same time it will promote the SO in the diesel engine exhaust 2 Catalyst poisoning by oxidation

It can be seen that a single high temperature effect is significant for V 2 o 5 -WO 3 / TiO 2 Catalyst or MnO with outstanding low temperature effect x -CeO 2 / TiO 2 Both are difficult to meet the requirements of diesel vehicle SCR, and the combined result of the catalytic performance of the two is what is needed by today's research.

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