Anti-crystallization device for carbamide nozzle of selective catalytic reduction (SCR) system

Abstract

Disclosed is an anti-crystallization device for a carbamide nozzle of a selective catalytic reduction (SCR) system. The anti-crystallization device comprises a solenoid valve, a vortex tube assembly and a spray head assembly. A gas inlet of the vortex tube assembly is provided with the solenoid valve. One end of the vortex tube assembly is connected with the spray head assembly through a cool gas pipeline, and the other end of the vortex tube assembly is connected with the spray head assembly through a hot gas pipeline. The spray head assembly is further provided with a carbamide inlet. The tail end of the spray head assembly is provided with a carbamide nozzle orifice, a hot gas nozzle orifice and a cool gas nozzle orifice. The carbamide nozzle orifice is nested in the cool gas nozzle orifice. The cool gas nozzle orifice is nested in the hot gas nozzle orifice. Compressed gas can be transformed into cool gas flow and hot gas flow. The cool gas flow can be used for cooling components in the spray head assembly. The hot gas flow can be used for heating carbamide. The cool gas flow and the hot gas flow finally produce gas curtains through the nozzle orifices and the gas curtains isolate carbamide mist and high-temperature tail gas at the nozzle, and carbamide crystallization produced at the nozzle is avoided to the greatest extent. At the same time, cooling and heating effects are achieved in different positions simply and reliably; the production and maintenance cost of the system is 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 the nitrogen oxides in diesel engine exhaust into nitrogen and water. As far as the engine exhaust aftertreatment system is concerned, the urea needs to be atomized and sprayed into the exhaust pipe to participate in the catalytic reduction reaction. Evaporation can 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 market to solve nozzle clogging. One is to wrap ceramic insulation material around the nozzle to reduce the heat absorbed by the nozzle body fr...

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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