SU1526730A1 - Method of back osmotic demineralization of mineralized water - Google Patents

Abstract

The invention relates to the desalination and desalting of natural and wastewater by reverse osmosis. The invention allows to increase the efficiency and reliability of the reverse osmosis desalting of saline water. The method includes reverse osmosis desalting of saline water by passing it under pressure through porous semipermeable membranes of a coiled membrane element to produce permeate and concentrate. The new method is the elimination of saline effluent discharges into the environment due to the fact that the concentrate is sent to the sump-crystallizer, and then the resulting sludge is returned to the original saline water. 1 il.

Description

The invention relates to the water supply and wastewater treatment in various areas, more specifically to the desalination and desalination of natural and cTOMfibix waves by reverse osmosis, and can be used in reverse osm plants (with a large percentage of the desalted water.

The purpose of the invention is to increase the efficiency and reliability of the method by eliminating the discharge of salt effluents into the environment.

In the drawing, an installation that implements the forerun method is given.

The installation consists of a high-pressure pump 1, an apparatus 2 with a rolled membrane element, a reduction valve 3, a settling tank, a crystallizer 4, and a meter wheel 5.

The method is carried out as follows.

Desalted saline water is pumped through a high-pressure pump 1 to an apparatus 2 with a rolled membrane element, where its reverse osmosis desalination takes place to produce permeate and concentrate. The permeate is delivered to the consumer, and the supersaturated, poorly soluble compound, they concentrate under pressure to the clarifier-crystallizer 4. Sludge and sediment are formed in the clarifier-crystallizer. The sludge is sent to mixer 5, where it is displaced with the original saline water.

In rolled membrane machines, it is possible to achieve supersaturation without precipitating

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sediment due to the fact that it is possible to create such a speed of movement of the treated liquid, at which the time of its stay in the apparatus will be less than the induction period of the formation of nuclei of crystals. The magnitude of the induction period depends on the degree of supersaturation of the solution with salt and for a solution containing, for example, 6.5-11.5 g / l of calcium sulfate, the induction period is 24 ± 4 minutes.

Example. Reverse osmosis desalination of saline water was carried out, representing a solution of 0.275 g / l of ССЕ and 0.805 g / l of Na: .SO4 in distilled water. The original saline water with a pressure of 4 MPa and a temperature of 22 ° C was sent to a rolled membrane element, where its reverse osmosis desalination took place to produce permeate and concentrate. The salt retention of porous semipermeable membranes was 95–96%, their productivity was by a factor of 160–180. The transit flow rate in the intermembrane pressure channel was more than I m / s. what is binbinie depolarization rate. The lane was removed from the casing of the membrane membrane element, and the concentrate, supersaturated with poorly soluble compounds, was sent to a settling tank-crystallizer. For two hours in the settling basin of the crystallizer, the concentrate was aged, which is necessary for the generation of levers to reduce, to form, and to form a precipitate. The resulting sludge was sent to the source water. After 34 hours of work in the indicated mode, it was revealed that a calcium sulfate precipitate had formed in the settling tank of the crystallizer, and no precipitate was detected in the coiled membrane element.

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The advantage of the proposed method is that the resulting concentrate is subjected to sludge to obtain solid sediment and pure sludge, i.e., if in a known part of the concentrate was discharged into the environment, and the other part was sent to the original saline water, which led to the formation of sediment on the membranes of the coiled element, then in the proposed method discharge of the concentrate into the environment is excluded, due to which the efficiency of the method is increased, and the initial saline water is shifted to clean sediment That does not cause formation of a precipitate on the membranes of the web member and the Enhance leads to the reliability of the method.

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Claims (1)

Invention Formula The method of reverse osmosis demineralization of saline water, which includes passing it under pressure through semipermeable membranes of a roll membrane element to produce permeate and concentrate, characterized in that, in order to increase the efficiency and reliability of the method, to prevent the discharge of salt effluents into the environment, the concentrate is oversaturated salts at the stage of the passage of water through the semipermeable membranes and are directed to the crystallization process with a rate that ensures the duration of the flow of the concentrate. ata the moment of arrival to Perez nJ.eni on mensche crystallization step than during the formation of crystallization nuclei, and then the concentrate is maintained until a siege ka, and the sludge fed to the source with obes-, shvaemuyu mineralized water.