Method for preparing molecular sieve SCR catalyst, and catalyst prepared therethrough

Abstract

The invention discloses a method for preparing a molecular sieve SCR catalyst, and the catalyst prepared therethrough. Several molecular sieves are mixed, and then undergo ion exchange modification treatment by a transition metal or a rare earth metal, Fe is loaded through isopyknic impregnation, and Cu is loaded through one-stage or multistage liquid ion exchange. A technology for modifying the stable molecular sieve mixture with the transition and rare earth metals, a technology for loading Fe by the isopyknic impregnation process and a technology for loading Cu by the one-stage or multistage liquid ion exchange are combined, and a catalysis material obtained through stable and effective modification and loading control is applied to a carrier matrix after being blended to form a slurryin order to prepare the monolithic catalyst; results of fresh sample activity test and hydrothermal aging test show that the catalyst has a wide active temperature window and excellent hydrothermal aging resistance, and the N2O generation amount of the catalyst prepared in the invention is significantly lower than that of previous catalysts of the same type.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, in particular to the technical field of molecular sieve SCR (Selective Catalytic Reduction, Selective Catalytic Reduction) catalyst preparation, and particularly relates to the preparation of a high-efficiency molecular sieve SCR catalyst for purifying diesel vehicle exhaust and the prepared catalyst. Background technique [0002] NOx is an important air pollutant and an important pollutant that forms photochemical smog and haze. With the rapid growth of the number of motor vehicles, NOx in motor vehicle exhaust has attracted widespread attention at home and abroad, and the technology for purifying NOx in motor vehicle exhaust has also been developed rapidly. As the share of diesel vehicles in automobiles continues to rise, diesel vehicle exhaust NOx purification technology has become a worldwide hot research topic. Ammonia selective catalytic reduction technology (NH 3 -SCR) is cu...

AI Technical Summary

Problems solved by technology

[0004] CN103127951A patent discloses a preparation method of a molecular sieve catalyst, which uses a low-cost mesopore / macropore molecular sieve as a carrier material and Cu and Fe as active components. Excellent anti-aging properties, however, in practical applications it was found that NH 3 - A large amount of N will be generated during the SCR reaction 2 O, showing lower N 2 selectivity

N 2 O is a strong greenhouse effect gas. Countries such as Europe and the United States have put N in the exhaust of diesel vehicles 2 The concentration of O is strictly limited, so this technical solution is subject to certain restrictions in practical industrial applications

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