Selective catalytic reduction (SCR) air mixing atomizing nozzle

Abstract

The invention provides a selective catalytic reduction (SCR) air mixing atomizing nozzle which comprises a nozzle inner cavity, a urea conveying pipe, an upper nozzle outer sleeve, a lower nozzle outer sleeve, a high-pressure air conveying pipe, a sprayer, a connection sleeve and a urea pipe joint. A plurality of large air inlets are evenly distributed in the circumferential face of the upper portion of the nozzle inner cavity. A plurality of small flow guiding holes are evenly distributed in the circumferential face of the middle portion of the nozzle inner cavity. A conical contractive channel hole is formed in the center of the bottom of the nozzle inner cavity. One end of the urea conveying pipe stretches into the nozzle inner cavity and is connected with the nozzle inner cavity; the urea conveying pipe penetrates through the upper nozzle outer sleeve and is connected to the upper nozzle outer sleeve, and the nozzle inner cavity and the upper nozzle outer sleeve are made to be coaxial; the other end of the urea conveying pipe is connected with the connection sleeve; the urea pipe joint is inserted into the other end of the connection sleeve; and one end of the high-pressure air conveying pipe is connected to the upper portion of the upper nozzle outer sleeve. According to the SCR air mixing atomizing nozzle, reinforced atomization is achieved three times, and finer and more uniform mist drops are obtained; in addition, the risk of ammonia leakage of an SCR system is effectively reduced, and the NOx conversion efficiency is improved; and the nozzle is not prone to blockage.

Description

technical field [0001] The invention belongs to the technical field of diesel engine tail gas treatment, and in particular relates to an SCR air mixing atomizing nozzle. Background technique [0002] The Selective Catalytic Reduction (SCR) system is currently recognized as one of the most effective post-treatment technologies for reducing NOx emissions from diesel engines. The SCR urea injection system injects a certain amount of urea solution into the exhaust pipe, and the urea solution is evaporated and pyrolyzed and hydrolysis process to obtain the reducing agent NH 3 , NH 3 Under the action of the catalyst, NOx is selectively reduced to N2, so as to achieve the purpose of reducing NOx emission. There are two main types of existing SCR urea injection systems according to the form of spray atomization, namely air-assisted SCR urea injection system and non-air-assisted SCR urea injection system. As emission regulations become more and more stringent, exhaust gas treatmen...

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Problems solved by technology

[0003] The commonly used air-assisted urea injection system generally realizes gas-liquid mixed atomization at the outlet of the urea metering pump, or realizes gas-liquid mixed atomization at the nozzle. The atomization degree of this structure is not good, and there is ammonia leakage risk, nozzles are prone to clogging

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