Modular Design Of Main Equipment Of LNG Fuel Power Marine Gas Supply System

LNG as a new type of green energy,has the characteristics of clean,efficient and economical.Nowadays global oil resources are exhausted day by day,the serious environmental pollution are increasing and transportation costs are also increasing.For these reasons,natural gas fuel shows a great advantage,it is very suitable for replacing fossil fuels,it is becoming the main engine fuel.Natural gas fuel,although have very successful applications in many fields,but in ship industry is still in the exploratory stage.Due to the high standard of the LNG powered ship's security and stability,there is no solution that can completely meet the requirements.This paper mainly completed the module design of interlock valve which is the key equipment of LNG fuel supply system.LNG fuel supply system include many devices,gas interlock valve group is the most key equipment.Interlock gas valve group include four emergency shut-off valve.One located in pipeline is low temperature valve,the other three closed to the engine compartment is normal temperature valve.Four valves are combinated to complete emergency cut off fuel gas supply and gas release.The interlock valve working principle and installation method are analyzed in this paper.Emergency shut-off valve of the type,structure are also briefly introduced in this paper.This paper put forward solving method of eliminating for emergency cut off valve safety fault and failure mode in daily operation.The focus of the article is modular design of interlock valve group.This paper compare the different modular design of this program and complete modular design of the interlock valve group.The three emergency shut-off valve of interlock valve group are designed as a three-way valve.This three-way valve has two working modes: gas supply mode and emission mdoe.Two kinds of working modes are achieved by tight fit in the valve flap and valve seat which are achieved by the moving up and down of the stem drived by the piston.The design of the valve achieved the overall design of the structure and the function integration.The three-way valve design can simplify the LNG fuel pipeline,save space and cost and make intenance more convenient.The selection of the design and calculation of strength about valve stem,discs,valve seat of the three-way valve are completed in this paper.Internal flow field simulation about the three-way valve has completed.The 3D model of gas supply mode is constructed by UG and 2D model of emssion mode is constructed by CAD.The models use Gambit to divide the grid,and the models are imported into Fluent to carry out the simulation.Inlet boundary conditions adopt velocity and exit boundary conditions adopt pressure.The simulation model adopt the standard two equation turbulence model.With the changing of inlet velocity and outlet pressure,it simulate and analysis the valve internal flow and pressure changes.Change the natural gas flow rate,which is the inlet flow rate,then compare the flow channel internal pressure.The results make the groundwork for further improvement of three-way valve design.as a follow-up to the three-way valve design improvement made the upholstery.At the end of this paper,the full text is summarized,and the future research focus is prospected.