Non-automotive heavy-duty diesel engine SCR (semiconductor control rectifier) device and method

Abstract

The invention relates to a non-automotive heavy-duty diesel engine SCR (semiconductor control rectifier) device and method. The non-automotive heavy-duty diesel engine SCR device comprises a reactor in which a catalyst is arranged; a measuring unit which is connected with a system control device is arranged at an exit of the rear end of the catalyst in the reactor; the system control device is connected with a spray gun through a urea solution control device; an exit end of the spray gun is arranged at a front end of the catalyst in the reactor; the measuring unit comprises at least an NOX (nitric oxide) measuring unit; the urea solution control device comprises a urea pump and a urea tank which is connected with the urea pump, and a spraying device which is connected with the urea pump; the spraying device comprises at least two one-way valves which are connected with an air compressor and the urea pump respectively; the system control device is connected with a urea pump signal control end so as to output a urea solution output signal; and the spraying device is connected with the spray gun. The device provided by the invention is provided with the spraying device and the air compressor so as to solve the problem of uniformly mixing large capacity of urea water solution with tail gas and the problem of uniform diffusion of the mixed urea water solution and the tail gas passing through the catalyst.

Description

technical field [0001] The invention relates to an SCR device, in particular to an SCR device and method for a non-vehicle heavy-duty diesel engine. Background technique [0002] The air pollution caused by NOx emitted by diesel engines has aroused strong reactions from all parties. During the 12th Five-Year Plan period, the state took the control of nitrogen oxides as a national compulsory control index and included it in the national economic and social development plan. [0003] At present, domestic research on SCR technology for vehicle diesel engines has made great progress and has entered the practical stage. SCR technology is to spray urea aqueous solution into the exhaust gas emitted by the unit. After the urea aqueous solution undergoes four steps of atomization, evaporation, pyrolysis and hydrolysis Ammonia gas is generated as follows: Evaporation: (NH 2 ) 2 CO (fog droplets) → (NH 2 ) 2 CO (solid or liquid) + H 2 O (steam) pyrolysis: (NH 2 ) 2 CO (solid or ...

AI Technical Summary

Problems solved by technology

Specifically, since the SCR system of non-vehicle heavy-duty diesel engines has a larger injection volume of urea aqueous solution than that of automotive diesel engine SCR systems, a series of new problems arise: the flow rate of urea aqueous solution tends to be unstable, and after the atomization of urea aqueous solution and exhaust gas Difficult to mix evenly, guaranteed to improve NO X The conversion rate and reduction of NH 3 escape amount, and because the amount of urea aqueous solution is very large, it is easy to block the pipeline after crystallization

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