Diesel selective catalytic reduction (SCR) post-treatment tail gas heat management system

Abstract

The invention discloses a diesel selective catalytic reduction (SCR) post-treatment tail gas heat management system, which is arranged between a diesel particulate filter (DPF) and an SCR part. An exhaust pipeline is divided into two branches, and a first electric baffle and a second electric baffle are arranged at an entrance and an exit correspondingly so as to control the proportion of tail gasflowing through each branch; and a heat storage device is additionally mounted in the first branch, and a cooling water sleeve is additionally mounted on the outer layer of the first branch. Exhausttemperature heat under the high load of a diesel is stored through the heat storage device and released under the low load, and thus the purpose of adjusting the temperature of an SCR catalytic converter is achieved; and in addition, the heat storage device is pre-heated through a cooling water circulation system, the exhaust gas is cooled under the high exhaust temperature conditions such as DPFregeneration, thus an SCR catalyst is protected against high-temperature impact, safe operation of the SCR catalytic converter is guaranteed, it is guaranteed that the SCR system operates within the catalyst appropriate temperature range, and thus the purposes of improving the NOx conversion efficiency, lowering NH3 escape, and lowering diesel N2O strong greenhouse gas emission are achieved.

Description

technical field [0001] The invention belongs to the field of diesel engine tail gas treatment, in particular to a diesel engine SCR post-treatment tail gas thermal management system. Background technique [0002] With the increasingly stringent emission regulations, diesel engine Selective Catalytic Reduction (SCR) NOx reduction technology has become one of the most effective ways to solve diesel engine exhaust pollution. With the release of the national VI emission regulations for heavy-duty diesel engines, a diesel oxidation catalyst (DOC) is installed before the SCR system to eliminate HC and CO, and a diesel particulate filter (DPF) is installed to eliminate particulate matter. In addition, in order to obtain higher In order to improve the NOx conversion efficiency, urea is over-injected to obtain more reducing gas NH3, and then an ammonia oxidation catalyst (ASC) is installed behind the SCR system to oxidize excess NH3 into N2. The installation of complex systems also ...

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Problems solved by technology

[0003] Due to the complex operating conditions of the diesel engine, the exhaust temperature fluctuates greatly. Under low temperature conditions, the NOx conversion efficiency is likely to decrease, and the overheating condition is also prone to occur, which not only leads to a decrease in the NOx conversion efficiency, but

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