Low-energy consumption seawater desalinating technology and low-energy consumption seawater desalinating device

Abstract

The invention discloses a low-energy consumption seawater desalinating technology and a low-energy consumption seawater desalinating device. The seawater is input into a seawater desalinating reverse osmosis membrane separation system under the drive of a high-pressure pump after being pretreated to separate and hold back all ions by a seawater desalinating membrane so as to obtain membrane permeate and concentrate, and the membrane permeate is secondly separated by a low-pressure reverse osmosis membrane separation system to be taken as drinking water; the concentrate generated by the seawater desalinating reverse osmosis membrane separation system enters the low-pressure reverse osmosis membrane separation system through a pipeline to obtain membrane permeate and concentrate in a separating way, and the membrane permeate is taken as life non-drinking water; the concentrate generated by the low-pressure reverse osmosis membrane separation system is introduced into a nanofiltration membrane separation system through a pipeline to remove most salts in seawater through a nanofiltration membrane, and the obtained membrane permeate can be used as water for flushing the toilet; one concentrate end is connected with an energy recovery device to recover the pressure energy of the concentrate to push a rotating shaft of the high-pressure pump, so that the pressure energy can be converted into the pressure energy for enabling the ultrafiltration membrane dialyzate to enter the seawater desalinating reverse osmosis membrane system, and the energy consumption for the high-pressure pump can be reduced, therefore, the special effects such as low energy consumption, high recovery rate, diversity of produced water quality and the like can be realized.

Description

technical field [0001] The invention relates to a seawater desalination technology and equipment, in particular to a low energy consumption seawater desalination process and its device. Background technique [0002] With the rapid development of the global economy, the demand for fresh water continues to grow, and fresh water resources are becoming more and more scarce. Seawater desalination, as one of the important strategic means to solve the shortage of fresh water resources, has broad development prospects. Among the many seawater desalination technologies, multi-stage flash evaporation, low-temperature multi-effect and reverse osmosis membrane are the three mainstream technologies. Among them, reverse osmosis membrane technology is a relatively advanced, stable and effective desalination technology. Compared with other technologies, it has many advantages such as simple process, convenient operation, easy control, and low operating cost. Therefore, it has obvious adva...

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Problems solved by technology

[0004] (1) Seawater recovery rate is low and energy consumption is high

At present, the recovery rate of 10,000-ton seawater desalination system is close to 40%. For small and medium-scale seawater desalination systems such as islands

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