Piping Design And Optimization Of High Pressure SCR System For Low-speed Marine Diesel Engine Shop Test

With the rapid development of shipping industry,the emission pollution caused by mari-ne diesel engine is also concerned by international environmental organization.For more eff-ective controlling the Marine diesel engine emissions of harmful gas,a new Tier ? emission standards in to greatly reduce the NOx emission limits,which makes the Marine diesel engine must be installed by affiliated denitration equipment.Selective catalytic reduction technology(SCR),as a mainstream denitration method for Marine diesel engines,has been praised and r-ecognized by ship owners and shipyards.For the engine builder plant,how to make the major components in the SCR system connected in series by pipelines into a closed system in engine shop test has become a subject worthy of elaboration and research.As an important part of the SCR system,SCR piping layout has an important influence on the safety and stable operation of the engine.In this paper,the MAN 6S35ME-B marine main engine ordered in actual production is taken as the prototype,and the high-pressure SCR system pipeline equipped with it is taken as the research object,designed to meet the SCR sy-stem in the engine various load conditions within the normal and smooth operation as the goal,Through pipeline pressure loss check,pipeline expansion analysis and pipeline stress simulat-ion,the preset pipeline is optimized and improved continuously,and finally the high-pressure SCR pipeline that meets the bench test requirements of the main engine plant is established,and the effect is tested in the shop test.The main contents of this paper include:(1)Introducing the adverse impact of the increase of emissions caused by the prosperous development of shipping industry on atmospheric environnent.An effective solution of denit-ration of marine diesel engine is put forward and its feasibility of marine diesel SCR technol-ogy is emphatically analyzed.The development status of domestic and foreign fields is deeply studied,and the research objectives and conten-ts are defined.(2)Expounding the influencing factors of SCR pipeline design in the main engine shop test,and introduces the engine structural parameters,components characteristics and the nec-essary links to be considered in the pipeline design of high pressure SCR.Combined with the construction space conditions around the selected test bed,the design plan is drawn up accor-ding to the basic flow of pipeline design.(3)Introducing the pressure boundary conditions of the HP-SCR system,selecting the 100%engine load point of discharge parameters as a guide for the design of pressured pipeli-ne of the system values,.Using the classic formula method and the fluid mechanics software method,optimizing the original design plan,comparing and discussing the pressure loss of the pipeline from these both calculation value data deviation value,in order to proves the acc-uracy of theoretical calculation and the feasibility of the simulation calculation under complex conditions.(4)While the main engine is running at full load,professional piping performance analy-sis software is used to analyze and simulate the pressure piping system.According to the resu-lts of overall stress analysis,the local stress concentration is strengthened.According to the analysis data of thermal deformation of pipeline,appropriate expansion joints are selected for pipeline.According to the calculation results of pipe support,the pipe support is strengthened and optimized.(5)In the actual shop test stage of the main engine,the pipeline performance of the theo-retically designed HP-SCR system is examined from two aspects.Not only monitoring the pr-essure,temperature,valve position and support status of the whole system pipeline,but also confirming the NOx emission value lower than the minimum prescribed limit required by IMO,which finally confirms the pipeline design meet the established requirement.