A mixing device for scr system

Abstract

The mixing device used in the SCR system provided by the present invention includes a mixing tube, a flow guiding device, a turbulence device and a flow splitting device, the mixing tube is used to connect with the exhaust pipe, and the urea solution and exhaust gas are placed on the front side of the inlet end of the mixing device. After preliminary mixing in the exhaust pipe, it enters the mixing tube. When the mixed material in the middle enters the mixing tube, it will be divided and mixed by the flow diversion device and the flow guide device. Multiple flow guide devices are arranged along the axial direction of the mixing tube, and the mixture can be mixed. Secondary mixing to make it more fully mixed, the mixture located between the deflector and the mixing tube is disturbed by the spoiler to complete the mixing during the flow process, and the urea solution and the exhaust gas of the diesel engine are fully mixed after multi-layer diversion and disturbance. Mixing makes the mixing and distribution of NOX and NH3 in the exhaust gas uniform, reduces the wear of the catalyst, improves the life of the catalyst and the efficiency of the SCR system.

Description

technical field [0001] The present invention relates to the technical field of exhaust gas treatment devices, in particular to a mixing device for an SCR system. Background technique [0002] With the increasingly strict emission regulations, the requirements for diesel engine NOx emission have been greatly increased. SCR exhaust after-treatment system is the mainstream solution to this problem at home and abroad. SCR system is composed of injection mixing system, control system, catalyst, mixing device. The mixing degree of urea solution and diesel engine exhaust in the SCR pipeline mixing device has an important influence on the NOx conversion efficiency, NH3 leakage and the formation of deposits in the urea injection system. The size will directly affect the reaction efficiency of the SCR system. If the mixing uniformity is too poor, the reducing agent in the exhaust gas will concentrate through the catalyst in a certain area, resulting in a decrease in the utilization ra...

AI Technical Summary

Problems solved by technology

[0002] With the increasingly stringent emission regulations, the requirements for NOx emissions from diesel engines have been greatly increased. The SCR exhaust after-treatment system is the mainstream solution to this problem at home and abroad. The SCR system is composed of an injection mixing system, a control system, a catalytic converter, and a mixing device. The mixing degree of urea solution and diesel engine exhaust in the SCR pipeline mixing device has an important impact on the NOx conversion efficiency of the urea injection system, NH3 leakage and the formation of deposits, and the mixing uniformity of the reductant and engine exhaust in the SCR system The size will directly affect the reaction efficiency of the SCR system. If the mixing uniformity is too poor, the reducing agent in the exhaust gas will concentrate through the catalyst in a certain area, resulting in a decrease in the utilization rate of the catalyst, incomplete reaction of the reducing agent, and excessive NH3 leakage. Consequences, so the mixing uniformity of reducing agent and engine exhaust gas is one of the important factors to ensure the efficiency of SCR

Images