CN-121976872-A - Engine tail gas aftertreatment system and method

CN121976872ACN 121976872 ACN121976872 ACN 121976872ACN-121976872-A

Abstract

The invention discloses an engine exhaust aftertreatment system and method, which belong to the technical field of engine exhaust treatment, and comprise at least two parallel pre-treatment modules, a shared aftertreatment module, a reducing agent supply injection module and a control module, wherein each pre-treatment module is respectively connected with a corresponding engine and is provided with an oxidation catalyst and a particle catcher for primarily purifying exhaust, the air outlet ends of all the pre-treatment modules are converged to the shared aftertreatment module, the modules are sequentially provided with a mixing section and a selective catalytic reduction reactor, the mixing section is provided with a reducing agent injection port, the reducing agent supply injection module comprises a storage tank and an injection unit connected with the storage tank, the outlet of the injection unit is connected with the reducing agent injection port, and the control module controls the injection quantity of the reducing agent according to signals monitored by a temperature sensor arranged on the shared aftertreatment module and a nitrogen oxide sensor arranged on the mixing section. The invention has compact structure and can realize the efficient cooperative treatment of the tail gas of the multiple engines.

Inventors

ZHOU SHENGBIN
LV YUNLONG
WEI XILONG
LI YANRONG
Lv Yabin
LIU MENG
JIANG YANG
ZHANG LI
CHENG XIANGYING
PU HAO

Assignees

中国石油集团济柴动力有限公司

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (10)

1. An engine exhaust aftertreatment system is characterized by comprising at least two pre-treatment modules, a shared aftertreatment module, a reducing agent supply injection module and a control module; The at least two pre-treatment modules are arranged in parallel, an air inlet of each pre-treatment module is used for being connected with a corresponding engine exhaust source, and each pre-treatment module comprises an oxidation catalyst and a particle catcher which are sequentially arranged along the tail gas flow direction and are used for primarily purifying the respective corresponding engine tail gas; The air inlet ends of the shared post-treatment modules are communicated with the air outlet ends of all the pre-treatment modules through pipelines, the shared post-treatment modules comprise a mixing section and a selective catalytic reduction reactor which are sequentially arranged along the tail gas flow direction, and the mixing section is provided with a reducing agent jet port; The reducing agent supply injection module comprises a storage tank and an injection unit connected with the storage tank, and an outlet of the injection unit is connected with a reducing agent injection port of the mixing section; The control module is in communication connection with a temperature sensor arranged on the sharing aftertreatment module, a nitrogen oxide sensor arranged on the mixing section and the reducing agent supply injection module, and is used for controlling the injection quantity of the reducing agent supply injection module according to the monitored temperature and nitrogen oxide concentration signals.
2. The engine exhaust aftertreatment system of claim 1, wherein the shared aftertreatment module further comprises a heater disposed upstream of the mixing section, the heater in communication with the control module.
3. The engine exhaust aftertreatment system of claim 2, wherein the shared aftertreatment module further comprises an ammonia slip catalyst disposed downstream of the selective catalytic reduction reactor.
4. The engine exhaust aftertreatment system of claim 1, wherein the reductant supply injection module further comprises a heat trace assembly that heats the storage tank and its delivery conduit.
5. The engine exhaust aftertreatment system of claim 1, wherein the reductant supply injection module further comprises a level detection module for detecting a reductant level in the storage tank.
6. The engine exhaust aftertreatment system of claim 2, wherein the control module is further configured to control the heater to start when the temperature of the shared aftertreatment module intake is monitored to be below a first set threshold, and to control the heater to stop or reduce power when the temperature reaches or exceeds a second set threshold.
7. The engine exhaust aftertreatment system of claim 1, wherein the control module is configured to calculate and control the injection amount of the reductant supply injection module based on pre-stored engine operating parameters and nox mapping and real-time monitored exhaust parameters.
8. The engine exhaust aftertreatment system of claim 1, wherein the oxidation catalyst, the particulate trap, and the selective catalytic reduction reactor each employ a modular packaging structure.
9. The engine exhaust aftertreatment system of claim 1, further comprising a flow sensor for monitoring exhaust flow, the flow sensor in communication with the control module, the control module capable of adjusting reductant injection amount based on the monitored exhaust flow.
10. An engine exhaust gas aftertreatment method applied to an engine exhaust gas aftertreatment system according to any one of claims 1 to 9, comprising: Receiving tail gas from at least two engines, and enabling each tail gas to be oxidized and trapped by particulates through an independent pre-treatment module; Merging the pre-treated tail gases and conveying the tail gases to a shared mixing section; Monitoring the temperature and the concentration of nitrogen oxides of the tail gas after merging; controlling the injection quantity of the reducing agent into the mixing section according to the monitored temperature and the concentration of the nitrogen oxides, so that the reducing agent is mixed with the tail gas; and introducing the mixed gas-liquid mixture into a shared selective catalytic reduction reactor to perform catalytic reduction reaction.

Description

Engine tail gas aftertreatment system and method Technical Field The invention relates to the technical field of engine tail gas treatment, in particular to an engine tail gas aftertreatment system and method. Background In the running process of an engine, particularly a test bench, fuel combustion can generate tail gas containing pollutants such as nitrogen oxides, carbon monoxide, hydrocarbon, particulate matters and the like, in order to meet increasingly strict environmental emission standards, a post-treatment device is required to be arranged in an engine exhaust system, and harmful substances are converted into harmless substances such as nitrogen, water and the like through means of catalytic reduction, oxidation, filtration and the like and then are discharged into the atmosphere. Common aftertreatment technologies include oxidation catalysts, particulate traps, urea injection systems, and selective catalytic reduction systems, etc., which typically work independently to achieve purging. However, the above prior art solutions have a number of drawbacks in practical applications: when a plurality of racks are densely arranged, the equipment is repeatedly built, so that the occupied area is huge, the initial investment cost and the subsequent maintenance cost are high, each module is independently heated, the temperature of the SCR catalyst is slowly increased during cold start, an optimal activity temperature window is difficult to reach quickly, particularly, the tail gas temperature is insufficient under a low-load working condition, the conversion efficiency of nitrogen oxides is low, and an auxiliary heater is often required to run for a long time with high power so as to ensure the reaction temperature, and the energy consumption is increased. The existing open-loop or semi-closed-loop urea injection strategy is difficult to accurately adjust the injection quantity in real time according to the flow of tail gas and the concentration of nitrogen oxides, excessive urea injection can cause unreacted ammonia gas to escape, secondary pollution is caused, insufficient injection can not fully reduce nitrogen oxides, and the emission exceeds standard, while under a low-temperature environment, urea solution is easy to crystallize and block a pipeline and a nozzle to influence the normal operation of a system, meanwhile, the existing device is mostly designed in a specific model or in a fixed working condition, and has poor suitability when facing different fuel types, displacement or variable working condition engines, needs customized development and lacks modularized flexible configuration capability. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides an engine tail gas aftertreatment system and an engine tail gas aftertreatment method, which are used for solving the problems of large occupied area, high cost, slow starting temperature rise, low catalytic efficiency and inaccurate urea injection control of a plurality of engine tail gas treatment systems and solving the problems of urea crystallization, system modularization and poor universality in a low-temperature environment, thereby realizing the tail gas purification targets of compactness, high efficiency, intelligent control, reliable operation and wide application range. The technical scheme of the invention is as follows: in a first aspect of the present invention, an engine exhaust aftertreatment system is provided that includes at least two pre-treatment modules, a shared aftertreatment module, a reductant supply injection module, and a control module; The at least two pre-treatment modules are arranged in parallel, an air inlet of each pre-treatment module is used for being connected with a corresponding engine exhaust source, and each pre-treatment module comprises an oxidation catalyst and a particle catcher which are sequentially arranged along the tail gas flow direction and are used for primarily purifying the respective corresponding engine tail gas; The air inlet ends of the shared post-treatment modules are communicated with the air outlet ends of all the pre-treatment modules through pipelines, the shared post-treatment modules comprise a mixing section and a selective catalytic reduction reactor which are sequentially arranged along the tail gas flow direction, and the mixing section is provided with a reducing agent jet port; The reducing agent supply injection module comprises a storage tank and an injection unit connected with the storage tank, and an outlet of the injection unit is connected with a reducing agent injection port of the mixing section; The control module is in communication connection with the temperature sensor arranged in the shared aftertreatment module, the nitrogen oxide sensor arranged on the mixing section and the reducing agent supply injection module, and is used for controlling the injection quantity of the reducing agent supply injection module accordi