Research On The Principle Of Submarine Seawater Reverse Osmosis Desalination Device In The South China Sea

In the submarine seawater reverse osmosis(SWRO)desalination technology,the inlet water was drawn from deep-sea high-pressure clean seawater source.Submarine SWRO represents the advantages of energy saving,no pretreatment,saving land occupied area and so on.It is one of the most promising development directions of reverse osmosis(RO)desalination technology which dominates the desalination market.The lack of freshwater resources in the South China Sea restricts the development there.This paper proposes a system of submarine reverse osmosis desalination in the South China Sea,which combines a new light three column semi-submersible platform for the exploitation of offshore oil and gas with a submarine reverse osmosis desalination device.The device and the platform are connected through a lifting device and a lifting cable.So that the device can be lifted and the flexibility of the device can be improved.The product water of the device can be supplied to the platform and transported to the nearby islands.Also the structure of desalination device is designed.In addition,according to the actual vertical distribution of seawater temperature salinity and density in the South China Sea,the application of the device is analyzed.The effect of the temperature,salinity and pressure of the inlet water on the product water yield and desalination rate of the device is calculated.It is also concluded that the device designed to reach the yield of 30 t/d needs to be placed in seawater of 512 m depth in the selected research location in the South China Sea,The influence of low temperature characteristics of the seawater in 512 m on the application depth of the device is also discussed.It is found that when the temperature of seawater at this depth increases from8.35 ? to 22 ?,the placement depth required for the device can be reduced to 456 m.Moreover the energy efficiency of the device is also preliminarily verified by calculation.Finally,the hydrodynamic performance of the submarine reverse osmosis desalination system is predicted by numerical simulation.The results of the underwater device motions and the cable tension are obtained and analyzed.This study has guiding significance for promoting the application of submarine reverse osmosis desalination technology in the South China Sea.