Deep sea reverse osmosis seawater desalination device and method thereof

Abstract

The invention relates to a deep sea reverse osmosis seawater desalination device. The device comprises a lifting device and a fresh water storage tank, wherein the lifting device and the fresh water storage tank are arranged on a semi-submersible ocean platform; the device body is arranged in an outer frame, and the outer frame is connected with the lifting device through a sling; the device bodyis immersed in seawater along with the outer frame and can be lifted along with the sling; the filter box of the device body is communicated with a seawater inlet main pipeline; a filter box, a waterinlet pump, a heating device and a reverse osmosis membrane element are sequentially connected with each other; the reverse osmosis membrane element is divided into three branches, a first branch is communicated with a fresh water tank, a second branch is communicated with a concentrated seawater discharge pipeline, and a third branch is communicated with a water return tank; the fresh water tankis connected with an air pipe which is communicated with the atmosphere; the fresh water tank is also connected with the fresh water storage tank through a high-pressure pump and a fresh water conveying pipeline. The device solves the problem of difficulty in maintaining and cleaning caused by placing devices in the deep sea; the device also solves the problems of low water yield and high water inlet pressure requirements caused by low seawater temperature, and increased cost caused by increase of the number of membrane elements.

Description

technical field [0001] The invention relates to a seawater desalination device, in particular to a deep sea reverse osmosis seawater desalination device. Background technique [0002] The deep-sea reverse osmosis seawater desalination device is placed in the deep sea, and uses the natural hydrostatic pressure of the deep sea to make seawater pass through the reverse osmosis membrane to produce fresh water, which greatly reduces energy consumption. At the same time, because the deep sea water is very clean, water can be produced without pretreatment or only needs to be roughly filtered, and the cleanness of the influent also reduces the possibility of membrane fouling. And because the water inlet high-pressure pump is omitted, the problem of reducing the overall performance and life of the membrane system due to the pulsating pressure wave generated by its vibration is also solved, and placing the device in the deep sea has the advantages of isolating noise, which is a low en...

AI Technical Summary

Problems solved by technology

[0004] 1) Difficulty in maintaining and cleaning in deep sea;

[0005] 2) The low seawater temperature in the deep sea reduces the production capacity of the device: at a depth of about 500 meters in the deep sea, the water temperature will be lower than 10°C, and the working performance of the reverse osmosis membrane is highly correlated with the inlet water temperature. The water production flux of the system is basically proportional to the water temperature, so the low temperature of deep-sea seawater will increase the inlet pressure and the number of membrane elements required by the deep-sea seawater desalination device under the same water production demand, thereby increasing the cost;

[0006] 3) The high-salinity concentrated seawater discharged underwater by the deep-sea reverse osmosis device may affect the flow field of the influent seawater and cause an increase in the salinity of the influent water, which in turn affects the salinity of the produced water and brings adverse effects on the operation of the device. At the same time, as the deep-sea seawater enters the reverse osmosis device to produce fresh water, the pressure of the concentrated brine at the outlet will be lower than that of the external seawater, so it is necessary to pressurize the concentrated water drainage pump to assist the concentrated water discharge, and to prevent the drainage from affecting the influent flow Due to the influence of the field, the distance between the drain and the water inlet needs to be maintained. If the vertical distance between the two increases, the drain will face greater external water pressure, which increases the energy consumption demand for the concentrated water drainage pump;

[0007] 4) The high-pressure environment in the deep sea also puts forward strict requirements on the pressure resistance of the device materials, but the design and manufacture of bulky high-pressure vessels also greatly increases the cost

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