Box type mixer for diesel engine tail gas treatment

Abstract

The invention discloses a box type mixer for diesel engine tail gas treatment. The box type mixer comprises a rotational flow pipe and an inner layer hole pipe, wherein the inner layer hole pipe is arranged inside the rotational flow pipe, one end of the rotational flow pipe and one end of the inner layer hole pipe are connected to a nozzle base, a nozzle for spraying urea solution is mounted on the nozzle base, one end, close to the nozzle base, of the rotational flow pipe is provided with a circle of rotational flow holes, rotational flow blades are arranged on the rotational flow holes, a plurality of vent round holes are uniformly distributed in the inner layer hole pipe, apertures of the vent round holes, corresponding to the position, of the rotational flow blades are larger than theapertures of the vent round holes in other parts, and a heat preservation part is arranged outside the rotational flow pipe. According to the box-type mixer, the opening diameter of the inner layer pore pipe is optimized, the gas inlet flow is increased, the mixing and crushing effects of the urea and the waste gas is enhanced, meanwhile, the heat preservation part is additionally arranged outside the rotational flow pipe, so that the heat loss of the mixer can be effectively reduced, the urea is not easy to form a crystal deposit inside the mixer, and the conversion efficiency of a catalystcan be improved.

Description

technical field [0001] The invention belongs to the diesel engine tail gas post-treatment technology, in particular to a box type mixer used for diesel engine tail gas treatment. Background technique [0002] SCR (Selective Catalyst Reduction) for diesel engine selective catalytic conversion system is installed in the exhaust system of diesel vehicles to catalytically reduce NOx in diesel engine exhaust to N 2 and O 2 The catalytic reduction device uses urea aqueous solution as the reducing agent. Urea aqueous solution is injected into the exhaust pipe upstream of the catalyst, and is hydrolyzed into CO under the action of exhaust gas temperature and airflow 2 And ammonia, ammonia as a reducing agent to reduce NOx into pollution-free nitrogen and water. [0003] The mixer is an essential and important part of the SCR system, which is used for NH 3 Mixing with exhaust gas, and the key technology of SCR system lies in NH 3 The uniformity of mixing with exhaust gas. At pre...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to provide a box-type mixer for diesel exhaust gas treatment, to solve the problem that urea crystals are easily formed on the inner layer hole tube of the mixer used for diesel engine exhaust aftertreatment in the prior art

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