The Application Research On Energy Recovery Technology Of Reverse Osmosis Desalination Process In Marine

Reverse osmosis desalination technology used in marine has been developing rapidly in recent 30 years with the continuous development of modern ship-building industry to far ocean and large-scaling.The energy consuming problem of reverse osmosis desalination technology has been a major issue restricting its development,while the energy recovery technology is the best the way to solve this problem effectively.By adding energy recovery equipment to the reverse osmosis desalination process,the energy consumption rate would be decreased through passing the energy stored in the high pressure concentrated seawater discharge from reverse osmosis membrane to the fresh sea water.Positive displacement energy recovery system which is suites for ships is studied in this paper.The study is divided into the following aspects: the equipment's structural design,the material's corrosion resistance of equipment,sealing system design and energy recovery performance evaluation.Firstly,by analyzing the structure of pressure-energy recovery equipment and miniaturizing the traditional positive displacement energy recovery equipment,this thesis puts forward an energy recovery principle with small volume and low-energy.The main structure of the equipment includes cylinder,pilot valves and directional control valves.Cylinder is responsible for recycling the high pressure energy of the seawater,while the pilot valves and directional control valves control the flow of seawater.Then a detailed structure design is completed,including the design of cylinder,end cover,and hydraulic manifold block,which ensures the feasibility of the equipment.Thirdly,duplex stainless steel with strong corrosion resistance is chosen for main parts of the energy recovery equipment in consideration of the particularity of its application working conditions,and sealing system for energy recovery equipment is designed to ensure its good sealing performance.High pressure pump and the water supply pump are selected respectively according to the technological process of the test platform for pressure-energy recovery equipment.Then the test platform is set up and monitoring interface is designed and the data collection for flow rate,pressure sensors and PLC is carried out.The results of performance test of the equipment shows that it can increase and release the pressure of the seawater successfully with a stable operation of the energy recovery process and small fluctuation of the flow rate and pressure.Meanwhile the effective energy conversion rate of the equipment is experimented and verified which ensure the conversion rate of the effective energy is above 90%,which meets the national standard.