Anti-crystallization device of urea nozzle in scr system

Abstract

The anti-crystallization device of the urea nozzle in the SCR system of the present invention includes a solenoid valve, a vortex tube assembly, and a nozzle assembly. The air inlet of the vortex tube assembly is provided with a solenoid valve. The nozzle assembly is connected, and the other end is connected to the nozzle assembly through a hot gas pipeline. The nozzle assembly is also provided with a urea inlet, and the end of the nozzle assembly is provided with a urea nozzle, a hot gas nozzle, and a cold air nozzle. In the cold air vent, the cold air vent is embedded in the hot air vent. Compressed gas can be converted into cold and hot air flow. The cold air flow can be used to cool the components in the nozzle assembly, and the hot air flow can be used to heat the urea. These two air flows finally pass through the nozzle to generate an air curtain to isolate the urea spray and high-temperature exhaust gas at the nozzle. The crystallization of urea at the nozzle can be avoided to the greatest extent, and at the same time, the effect of cooling and heating can be realized in different positions simply and reliably, and the production and maintenance costs of the system are low.

Description

technical field [0001] The invention relates to the technical field of engine exhaust gas treatment, in particular to an anti-crystallization device for a urea nozzle of an SCR system. Background technique [0002] SCR (Selective Catalytic Reduction, Selective Catalytic Reduction), refers to the use of catalysts to catalytically reduce nitrogen oxides in diesel engine exhaust into nitrogen and water. For the engine exhaust aftertreatment system of the SCR reactant, it is necessary to atomize the urea and spray it into the exhaust pipe to participate in the catalytic reduction reaction. However, when the urea spray is sprayed from the nozzle and directly contacts the high-temperature exhaust gas, the The rapid evaporation of water will easily cause urea to crystallize and adhere to the small holes of the nozzle, thereby clogging the nozzle, which is especially obvious in the stage of small dose injection. [0003] At present, there are roughly two types of devices on the mar...

AI Technical Summary

Problems solved by technology

The disadvantages of this solution are: special branch pipes need to be added to the exhaust pipe, which is complicated to manufacture, and the interchangeability and versatility are not good; If there is leakage, it may cause the water pressure of the engine cooling system to be low and cause the engine to fail to work normally; in addition, the nozzle of this solution will still be in direct contact with the high-temperature exhaust gas

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