SCR reprocessing piping device of large-duty engine

Abstract

The invention discloses an SCR post treatment pipeline device for a large displacement engine, which includes an ejection pipeline. The ejection pipeline is provided with at least one nozzle that can spray carbamide liquor in the ejection pipeline. The nozzle is mounted on the ejection pipeline in a mode that the spraying direction is along the flow direction of the smoke body in the ejection pipeline and the spraying axis of the nozzle forms an included angle together with the axis of the ejection pipeline positioned along the spraying direction of the nozzle. Mixers are respectively arranged along the spraying direction of the nozzle in the ejection pipeline. The device can lead the carbamide liquor to be fast hydrolyzed to release ammonia and uniformly mixed with waste gas. The hydrolyzing rate of the carbamide is higher, thus leading an NOx compound to have longer reaction time and to be fully reacted and leading the SCR system to have higher waste gas conversion rate.

Description

technical field [0001] The invention relates to an engine exhaust aftertreatment device, in particular to an SCR aftertreatment pipeline device for a large-displacement engine used for treating engine exhaust using SCR technology. Background technique [0002] With the development of society and the concern about environmental pollution, people have increased the intensity of environmental protection, and the emissions of motor vehicles are the main pollutants in the atmosphere. Therefore, for the emissions of motor vehicles, people use various At present, the main engine post-treatment technologies used by people include cooling EGR (exhaust gas recirculation), NOx adsorber, SCR (selective catalytic reduction) and DPF (exhaust gas recirculation plus Particulate filter) and other post-treatment technologies. Among them, the use of SCR technology to deal with harmful substances in engine emissions, especially NOx compounds is a very effective method. The engine SCR post-tre...

AI Technical Summary

Problems solved by technology

The engine SCR post-treatment technology is to spray the reducing agent urea solution into the exhaust gas of the engine. Under the action of the exhaust gas temperature and air flow, the urea can quickly decompose and release ammonia, which can interact with the high content of NOx to reduce NOx emissions. , because the reductant of the SCR system is urea, which has stable performance in the non-use state, and has the advantages of simple chemical reaction and relatively small amount of reductant, which has been popularized and used by people. It is because urea can quickly decompose and release ammonia in a short time and evenly mix with exhaust gas, and fully react with NOx in the exhaust gas under the action of the catalyst to reduce the NOx compound in the exhaust gas. In the current engine SCR after-treatment system, After the urea solution is sprayed into the exhaust gas emitted by the engine, it cannot fully decompose and release ammonia in a short time, the hydrolysis rate of urea is low, and the uniformity of mixing with the exhaust gas is also low, which makes the released ammonia and The reaction time of NOx compounds is short and the reaction is incomplete, which reduces the conversion rate of exhaust gas, especially for large-displacement engines with fast flow rate, large flow rate and large exhaust gas treatment capacity.

This greatly affects the effect of the SCR system on the aftertreatment of engine emissions, and affects people's treatment of engine emissions

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