Full-membrane method seawater desalting integration system adopting ultrafiltration-nanofiltration-reverse osmosis, and full-membrane method seawater desalting integration process adopting ultrafiltration-nanofiltration-reverse osmosis

Abstract

The invention relates to a full-membrane method seawater desalting integration system adopting ultrafiltration-nanofiltration-reverse osmosis, and a full-membrane method seawater desalting integration process adopting ultrafiltration-nanofiltration-reverse osmosis, wherein the nanofiltration seawater softening recovery rate can be increased, and the membrane surface scaling tendency can be reduced. According to the present invention, the nanofiltration system is a three-stage nanofiltration system, wherein the first-stage nanofiltration membrane assembly and the second-stage nanofiltration membrane assembly are adopted as the pretreatment of the reverse osmosis, and the third-stage nanofiltration membrane assembly further treats the concentrated water obtained through the first-stage nanofiltration and the second-stage nanofiltration, such that the seawater recovery rate is increased, and the scaling tendency on the nanofiltration membrane surface of the first-stage nanofiltration membrane assembly and the second-stage nanofiltration membrane assembly is reduced so as to reduce the seawater desalting cost and reduce the scaling tendency of the third-stage nanofiltration membrane assembly during the high salinity concentrated water treatment.

Description

technical field [0001] The invention belongs to the technical field of seawater desalination and water treatment, and in particular relates to an integrated system and an integrated process for seawater desalination using ultrafiltration-nanofiltration-reverse osmosis. rate and reduce the fouling tendency of the membrane surface. The invention further relates to a method for alleviating fouling tendency of the membrane surface of the nanofiltration membrane when the nanofiltration membrane treats high-concentration brine. Background technique [0002] Nanofiltration membrane is a new type of separation membrane developed after reverse osmosis composite membrane in the 1980s. Its pore size range is between ultrafiltration membrane and reverse osmosis membrane, about 1nm, so it is called nanofiltration. membrane. [0003] The nanofiltration membrane belongs to the pressure-driven membrane, which has two remarkable features: one is that its molecular weight cut-off ranges fro...

AI Technical Summary

Problems solved by technology

Some chemicals added to the water when the patent treats high-salinity concentrated water will make the concentration in the nanofiltration concentrated water higher, which will interfere with the subsequent reuse of concentrated water

[0008] In the prior art, in the whole-membrane seawater desalination process, the recovery rate of the nanofiltration system is generally about 50%. surface fouling problem

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