Air inlet pipe of SCR tail gas processing system and SCR tail gas processing system

Abstract

The invention discloses an air inlet pipe of an SCR tail gas processing system. The air inlet pipe comprises a first guiding pipe and a second guiding pipe arranged outside the first guiding pipe in a sleeved mode. The side wall of the first guiding pipe is provided with a plurality of first guiding holes, and the side wall of the second guiding pipe is provided with a plurality of second guiding holes. The air inlet end of the first guiding pipe is connected with a urea nozzle of the system and an engine exhaust pipe. The second guiding holes are connected with a catalyst reactor of the system. According to the double-layer air inlet pipe, the air disturbance is increased through the double layers of guiding holes of the double-layer air inlet pipe, the probability that liquid urea drops touch the inner wall of the air inlet pipe is reduced, the urea is prevented from being crystallized, the liquid urea drops and the tail gas can be evenly mixed in the flowing process, and the utilization rate of the liquid urea drops is improved. In addition, the air inlet pipe has a good insulating function. The invention further provides the SCR tail gas processing system with the air inlet pipe.

Description

technical field [0001] The invention relates to the technical field of automobile tail gas treatment equipment, in particular to an intake pipe of an SCR tail gas treatment system and the SCR tail gas treatment system. Background technique [0002] SCR (Selective Catalytic Reduction) exhaust gas treatment system is one of the main post-treatment technologies for eliminating nitrogen oxides in diesel engine exhaust. [0003] The basic working principle of the SCR exhaust gas treatment system is: the exhaust gas flows out of the turbocharger turbine and enters the intake pipe of the SCR exhaust gas treatment system, and at the same time, the urea injection unit installed on the intake pipe sprays a certain amount of urea aqueous solution into the air in the form of mist. In the intake pipe, urea droplets (its molecular formula is NH 2 CONH 2 ) undergoes hydrolysis and pyrolysis reactions under the action of high-temperature exhaust gas, [0004] NH 2 CONH 2 +H 2 O→2NH 3...

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Problems solved by technology

[0011] Secondly, due to the small disturbance to the air flow, the mixing of urea droplets and exhaust gas flow is not uniform enough, resulting in low utilization rate of urea droplets, low conversion efficiency of nitrogen and oxygen, large leakage of ammonia gas, and poor noise reduction effect. It affects the reliability and adaptability of the SCR exhaust gas treatment system

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