The Optimum Design And Simulation Of Hybrid Systems For Marine SCR

With the increasing environmental problems,air pollution has become a hot issue of social concern.As an important part of air pollution the ship's exhaust gas is got more and more attention by people.The development of ship exhaust gas abatement technologies is facing new challenges.Meanwhile,the entry into force of MARPOL Annex VI also raised new requirements for the development of ship exhaust gas abatement technologies.The combustion products of ship fuel oil mainly comprising sulfur oxides,nitrogen oxides and particulate matter(PM2.5)and the like.In various of ship exhaust gas abatement technologies for removal nitrogen oxides,Selective Catalytic Reduction(SCR)is a abatement technology for NOx which can be used alone to meet the standards Tier III.Current research of SCR technology on thermal power plants and diesel engines of vehicles is more in-depth.The research and optimization of the flow field of marine diesel engine SCR system is mainly carried out by numerical simulation method.The Computational Fluid Dynamics(CFD)software is Fluent in this paper.The object of study is the Urea-SCR system of MAN B&W 6G60ME-C9.2 marine engines.It sets up a numerical model to simulate the process of mixing the urea and diesel exhaust in SCR system and optimize the design of the flow field.The main work includes the numerical simulation of SCR flow field and the selecting of the program about jet nozzle and mixer.The main contents are as follows.1.Based on the knowledge of CFD,it uses the ICEM for meshing.It uses the Fluent for simulation.By analyzing during mixing it gets effect of different factors including the exhaust velocity and turbulence intensity.2.It uses Fluent to simulation and modeling.Its research objects include the distance of the injection point and the inlet of expansion pipe,the direction of injection,the number of nozzle holes and the pore size and so on.It finally chooses the nozzle program for MAN B&W 6G60ME-C9.2 marine engines.3.By analyzing and comparing the effects of different mixer on the flow rates,distribution of ammonia and other factors,it selects suitable mixer for MAN B&W 6G60ME-C9.2 marine diesel.