Mixing device for diesel engine urea SCR system

Abstract

The invention discloses a mixing device for diesel engine urea SCR system, comprises a tube body, a mixer fin device and a nozzle. The invention is characterized in that: the nozzle is arranged on the central axis of the tube body; the mixer fin device adjoins to the nozzle and is installed at the front end of the nozzle; the mixer fin device is composed of a set of fins; the main body of the fins is a sector structure twisting along the air-flow direction, and the arrangement direction of the fins is consistent with the spray axis direction; a set of inclined flow deflector is arranged in each fin. The mixer fin device of the invention guides the air-flow to flow to the center along the fin direction, and strong flow-disturbing can be formed in the fan-shaped center end to promote atomization and mixing of the spray at the nozzle exit, thereby fully mixing the urea aqueous solution injected from the nozzle and the tail gas before flowing into SCR catalytic reactor, reducing urea crystallization on the wall surface, at the same time, the mixing device is compact in structure, easy to process and install and the effect of the device is verified by calculation and analysis by means of special-purpose design software.

Description

technical field [0001] The patent of the present invention relates to the field of diesel engine exhaust aftertreatment system, and more specifically relates to a mixing device for diesel engine urea SCR system. Background technique [0002] As countries around the world have stricter requirements on diesel engine emissions, diesel particulate matter (PM) and NO X Emission control has become a key technology for the development of diesel engines. At present, there are two different routes for diesel engine exhaust after-treatment technology for diesel engines to meet the requirements of my country's National IV emission regulations: one is to reduce the NOx emissions of engine cylinder combustion through exhaust gas recirculation (EGR) technology, and then use diesel particulate filter (DPF) to control PM; the other is to reduce PM emissions from combustion in the engine cylinder through high-pressure fuel injection technology, and then use selective catalytic reduction tech...

AI Technical Summary

Problems solved by technology

Although the urea SCR system is being promoted and applied all over the world, there are still many problems to be solved, such as: how to improve the conversion efficiency of NOx at low temperature, how to reduce the formation of deposits, low conversion efficiency caused by factors such as uneven mixing and ammonia leak etc.

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