Design And Simulation Of Double Piston Reciprocating Pressure Exchanger Energy Recovery Device

Seawater reverse osmosis desalination technology has developed into an important desalination approach.Energy recovery device is one of the three key equipments for reverse osmosis desalination system;it is vital importance to substantially reduce the energy consumption of the system and the cost for water output.In the seawater desalination project,the flow of salt water and the sea water are so large that an energy recovery system is required to have a good dynamic performance.In the fast commutation process of reciprocating motion of energy recovery,it could cause the system pressure fluctuations,while the volatility shocks of pressure will affect the life of the reverse osmosis membrane and the quality of water output.Therefore,the study of dynamic performance energy recovery,finding the main factors affecting the changes in pressure and flow,proposing pressure fluctuations suppression method for reducing impact noise commutation devices and pressure impact on the desalination membrane damage,thereby reducing the cost of desalination has important effect.Due to the expensive cost of materials and the high cost of processing fees for experiments,taking into account the complexity and economy of the research questions,as the well as the computer simulation technology currently supported conditions,the subject used the combination of structural design,theoretical analysis,experimental investigation and simulation comparison methods to carry out research on the dynamic characteristics of the double piston cylinder controlled by valve in energy recovery process,its main contents and conclusions of this paper are as follows:1.Proposed a self-aligning dual piston reciprocating pressurized cylinder,analyzed the key technology for energy recovery cylinder which designed in seawater,the paper designed and calculated structure and parameters of the energy recovery cylinder in detail,according to the working environment and strength hardness requirements of energy recovery cylinder,the paper selected appropriately 316L austenitic stainless steel as a structural material,the structure is determined by the form of cylinder static seal and dynamic seal forms,the use of magnetic proximity switch control cylinder commutation is Proposed,and finally the paper had verified the control scheme feasibility through experiment.2 For 4/2 directional control valve processing and assembly carried out after the experimental study,experimental results show that its performance of static commutation meets the design logic functions,which verify the valve design is reasonable.Through single factor experiment testing,the research of pilot valve orifice size,cartridge valve spool return spring,cartridge valve spool valve cover orifice size affect the hydraulic valve dynamic performance.3.By using AMESim software,the chapter established the simulation model of dual piston reciprocating energy recovery's key components of 4/2 directional control valve and cylinder energy recovery,meanwhile,the simulation curve and the major variation is analyzed to verify the correctness of the model.After established the model of energy recovery cylinder,its main parameters and buffer location simulate batch run and elect the optimum parameters.4.According to the results of single factor experiment,the paper designed virtual orthogonal test of 4/2 directional control valve,based on AMESim software to study the impact of various factors and level on the dynamic performance of directional valve.The results of simulation showed that the order of the factors that affecting the dynamic performance was the size of pilot valve orifice,the size of cartridge valve spool and sleeve orifice,the parameters of cartridge valve spool return spring.When the pilot valve P,T port orifice size is 5.8mm,cartridge valve spool damping size is 4.5mm,damping valve sleeve size is 4mm,the return spring stiffness is 7.2N/mm,pre-compression force is 40N,the valve can obtain better dynamic performance.5.The paper established an integrated simulation model of energy recovery to study the dynamic characteristics of 4/2 directional control valve,valve rectifier coupled with pressurized cylinder to run together.The paper focused the research on the changes in the energy recovery process reciprocating cylinder outlet flow and pressure,the dynamic performance of the system inputs and outputs on the total pipeline,the impact of fluctuations in the input flow export dynamic performance of the system.For the system's flow and pressure pulsation problem,the paper set the accumulator in the main flow channel to absorb pulsation.Simulation results show that:the inflation pressure accumulator and the larger inflatable volume,the smaller the flow at the outlet of the uniformity coefficient of system,the smaller the amount of pressure fluctuations.When the accumulator pressure to 55Bar,volume 18L,the pressure overshoot can be controlled within 15%.