A scr diesel engine aftertreatment system

Abstract

The invention relates to an SCR (Selective Catalytic Reduction) diesel engine posttreatment system, which comprises an SCR catalyst, a urea jet device, a heating device and a control device, wherein the SCR catalyst is used for carrying out reduction reaction on tail gas in a diesel engine exhaust pipe; the urea jet device is used for jetting urea into the diesel engine exhaust pipe; the heating device is arranged in the diesel engine exhaust pipe and used for heating urea jetted by the urea jet device; and the control device is used for deciding whether to heat a heating module or not according to the temperature of the tail gas in the diesel engine exhaust pipe and the work condition of a diesel engine, and controlling the power required by heating. According to the SCR diesel engine posttreatment system, the urea can be fully hydrolyzed under any exhaust temperature, and nitric oxide in the tail gas can completely react to produce harmless nitrogen and water, so the firing point of the SCR system can be effectively reduced, the exhaust dead point of the tail gas is greatly shortened, the efficiency of the system is greatly improved, and the emission standard of high specification is met. In addition, the SCR diesel engine posttreatment system is wide in applicable range, and is suitable for air-assist systems and air-assist-free systems.

Description

technical field [0001] The invention relates to the field of tail gas treatment, in particular to an SCR diesel engine post-treatment system. Background technique [0002] SCR diesel engine after-treatment system is an important system to deal with diesel engine exhaust pollution. It is mainly used to reduce nitrogen oxides in exhaust gas. It has the advantages of high treatment efficiency, does not affect engine performance and efficiency, and is not sensitive to sulfur content in diesel oil. . [0003] The basic working principle of the SCR system is: according to the working conditions of the engine and the temperature of the exhaust pipe, spray an appropriate amount of urea solution into the exhaust pipe, and the urea solution will be hydrolyzed into ammonia and carbon dioxide under the action of high temperature in the exhaust pipe. Under the action of the catalyst, ammonia reacts with nitrogen oxides in the tail gas to generate harmless nitrogen and water, thereby ach...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide an aftertreatment system for SCR diesel engines, so that when the exhaust gas temperature is not high enough, there is still a sufficient amount of urea hydrolyzed into ammonia, thereby reducing the ignition point of the SCR system, that is, nitrogen Temperature required for oxide conversion to reach 50%

Images