State-sixth-stage SCR front-end urea mixing structure

Abstract

The invention provides a state-sixth-stage SCR front-end urea mixing structure. The state-sixth-stage SCR front-end urea mixing structure comprises a bell mouth cylinder body, a heat insulation innerlayer cylinder body, a gas cyclone blade pipe, a stainless steel winding net, a front partition plate, a spoiler, a spherical plug cover, a nozzle seat supporting base and a nozzle seat; the stainlesssteel winding net is welded at the bottom of the cyclone blade pipe, and the spherical plug cover is arranged at one end of the heat insulation inner layer cylinder body; the heat insulation inner layer cylinder body is arranged in the bell mouth cylinder body; the front partition plate is arranged between the heat insulation inner layer cylinder body and the bell mouth cylinder body; the spoileris arranged on the inner wall of one side, located on the spherical plug cover, of the bell mouth cylinder body; and the nozzle seat supporting base is welded at the position, on the top of the gas cyclone blade pipe, of the bell mouth cylinder body, and the nozzle seat is welded on the nozzle seat supporting base. According to the structure, the gas flow velocity and the gas flow distribution state of the tail gas are improved by utilizing the gas cyclone blade pipe, so that the atomized urea and the tail gas are fully mixed, the gas flow field before the catalyst and the ammonia concentration uniformity are improved, and the content of pollutants in the tail gas is reduced.

Description

technical field [0001] The invention belongs to the technical fields of vehicle engine exhaust emission purification technology and energy saving and consumption reduction technology, and in particular relates to a urea mixing structure at the front end of a National VI SCR. Background technique [0002] According to the requirements of the "Heavy-duty Diesel Vehicle Pollutant Emission Limits and Measurement Methods (China Phase VI)" issued by the Ministry of Environmental Protection and the State Administration of Quality, heavy-duty diesel vehicles plan to implement the National VI emission standards in 2020. Factories are focusing on the reserve of National VI technologies. The technical route of the current National VI heavy-duty diesel engine is a series combination of oxidation catalyst unit (DOC) / particulate capture unit (DPF) / selective catalytic reduction conversion unit (SCR) and ammonia oxidation catalytic unit (ASC). Most diesel engines only contain selective cat...

AI Technical Summary

Problems solved by technology

The technical route of the current National VI heavy-duty diesel engine is a series combination of oxidation catalyst unit (DOC) / particulate capture unit (DPF) / selective catalytic reduction conversion unit (SCR) and ammonia oxidation catalytic unit (ASC). Most diesel engines only contain selective catalytic reduction conversion units, so the aftertreatment of China VI is more complicated than the hybrid structure of China V, and the requirements for anti-urea crystallization are higher

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