Study On Exhaust Aftertreatment Technology Of Mining Flameproof Diesel Engine

Flameproof diesel engine is one of the most widely used power devices in mine auxiliary transportation equipment,which plays an important role in coal mine production.Under the influence of flameproof transformation and harsh underground environment,the exhaust pollution of flameproof diesel engine is serious,which greatly endangers the physical and mental health of underground workers.Exhaust aftertreatment technology is a necessary technical means for road diesel vehicles,but at present,the research on emission control technology of flameproof diesel engine is mainly focused on improving in cylinder combustion and optimizing flow characteristics of intake and exhaust system.With the increasingly stringent emission regulations,it will be the inevitable direction for the development of emission control technology of flameproof diesel engine to adopt efficient aftertreatment technology to purify exhaust gas.Therefore,it is of great theoretical significance and practical value to carry out the research on the exhaust aftertreatment method of flameproof diesel engine and design exhaust aftertreatment system suitable for flameproof diesel engine to promoting the development of emission control technology of flameproof diesel engine and promoting the construction of green mine.In this paper,a certain type of flameproof diesel engine is taken as the research object,and the design and optimization for exhaust aftertreatment system are studied through the combination of simulation and experiment.Firstly,according to the development trend of emission regulations and requirements of coal mine safety regulations,the exhaust gas purification process and aftertreatment technology route suitable for flameproof diesel engine are discussed.It is determined that the "four element" combined exhaust aftertreatment process of "DOC+DPF+SCR+flameproof components" is adopted in the exhaust aftertreatment system of flameproof diesel engine.Secondly,using the underground hybrid trackless rubber tyred vehicle test platform,the external characteristic operation test of the flameproof diesel engine is carried out.According to the test results,the performance simulation model of the flameproof diesel engine based on GT-Power software is checked,which provides the necessary boundary conditions for optimization design of the aftertreatment system,and establishes the foundation for coupling analysis of the aftertreatment system and the flameproof diesel engine model basis.Then,the simulation models of DOC,SCR and DPF aftertreatment units are built by GT-Power software,and the optimization design of the exhaust aftertreatment device is studied.The main contents include: discussing the exhaust boundary conditions and key structural parameters on the performance of aftertreatment device,and optimizing the structure by using orthogonal test.The coupling model of flameproof diesel engine and aftertreatment system is established to carry out simulation analysis,and the accuracy of simulation results is verified by platform test.The results show that the CO purification efficiency is more than 95%,NO purification efficiency is more than 90%,HC purification efficiency is more than 83%,and the particulate matter capture efficiency is more than 97%.Generally speaking,the exhaust aftertreatment system designed could effectively reduce the pollutant emissions,which has a good reference value for the development of emission control technology of flameproof diesel engine.Finally,in view of the contradiction between the low temperature requirement of flameproof(surface temperature < 150℃)and the high temperature requirement of exhaust aftertreatment(reaction temperature > 300℃),the fluid structure coupling heat transfer analysis of the exhaust pipe water-jacket is carried out by using STAR-CCM+,and the fluid flow and heat transfer in the exhaust pipe are studied.On the basis of eliminating the dead zone of cooling water flow,the influence of thickness of water-jacket,the temperature of cooling water and the flow rate of cooling water on surface temperature and the internal exhaust temperature of the exhaust pipe are discussed,which could provides theoretical guidance for flameproof retrofit of exhaust aftertreatment device.This paper has 69 figures,10 tables and 103 reference.