Sea water desalination apparatus and method

Abstract

The invention relates to a sea water desalination apparatus and method, relates to the technical field of sea water treatment and is intended to improve operational stability and safety of a system and reduce operational cost of the system. The sea water desalination apparatus comprises a low-pressure membrane separation device and a low-pressure membrane desalination device; according to the characteristic of the low-pressure membrane separation device intercepting salts partially, monovalent saline water (namely sodium chloride solution) and divalent saline water (such as magnesium chloride,calcium chloride and sulfate solutions) are separated; the low-pressure membrane separation device can bear part of osmotic pressure in order to reduce the burden on its downstream equipment; since saline water on two sides of a membrane can counteract part of the osmotic pressure, operational pressure of the system is reduced greatly; since the sodium chloride solution separated by the low-pressure membrane separation device has reduced salt content, the osmotic pressure is reduced greatly; therefore, the objectives of desalination and production of qualified desalinated water can be achieved under low operating pressure.

Description

technical field [0001] The invention relates to the technical field of seawater treatment, in particular to a seawater desalination device and method. Background technique [0002] Seawater desalination is the use of seawater desalination to produce fresh water. It is an open-source incremental technology to realize the utilization of water resources. It can increase the total amount of fresh water and is not affected by time, space and climate. It can ensure a stable water supply for coastal residents, such as drinking water and industrial boiler replenishment. The existing seawater desalination membrane separation device and desalination method are seawater through a certain pretreatment, generally using high pressure (greater than or equal to 4Pa) reverse osmosis (8MPa) method to overcome the extremely high osmotic pressure of seawater salt, desalination and desalination to obtain fresh water. In order to ensure the effect of one-time desalination and prevent pollution, t...

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Problems solved by technology

In order to ensure the effect of one-time desalination and prevent pollution, this method has the following defects, such as the high osmotic pressure of seawater must be overcome, especially the salinity of the concentrated solution doubles under the high recovery rate, and the osmotic pressure is higher. High, so that the operating pressure is higher, so it is not conducive to the stability and safety of the system. In addition, the existing seawater desalination membrane separation device has high investment and operation costs, and the application rate of seawater desalination is low.

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