EA029264B1 - Method of desalination and purification of highly mineralized water from boron to drinking water standards - Google Patents

Abstract

The invention relates to methods of desalination and purification from boron to drinking water standards using a method of back osmosis of highly mineralized water, in particular, of Caspian sea water, characterized by a wide range of temperature changes and a high boron content, and can be used in systems of drinking water treatment. The technical task of the proposed invention is the simplification of technology of desalination and purification of highly mineralized water from boron, power and chemicals cost reduction for desalination process bringing the purified water quality to the drinking standards. The technical result is achieved by feeding sourcewater to membranemodules using high-pressure sea membranes with boron high selectivity, concentrate of which is fed to the membrane modules using low-pressure highly-selective membranes for brackish water, wherein the treated water (permeate) of any membrane modules, except the first one, can be either directed to consumers into a drinking quality water flow, or to a technological process upstream for improving the source water quality. The proposed invention claims have proved that the set tasks are fulfilled completely.

Description

The invention relates to methods of desalination and purification from boron to drinking quality by the method of reverse osmosis highly mineralized water, in particular the sea water of the Caspian Sea, which has a wide range of temperatures and high boron content, and can be used in drinking water treatment systems. The technical task of the invention is to simplify the technology of desalination and boron removal of highly mineralized water, reducing the cost of electricity and chemicals in the process of desalination with bringing the quality of purified water to drinking norms. The technical result is achieved by supplying the source water to membrane modules using high-pressure marine membranes with high boron selectivity, the concentrate of which is fed to membrane modules using low-pressure highly selective membranes for brackish water, and the purified water (permeate) of any membrane modules except first, it can be directed either to the consumer into the drinking water quality stream, or to the technological process head to improve the quality of the source water. The submitted materials on the application for the invention show that the tasks are performed in full.

029264 Β1

029264 Β1

029264

The invention relates to reverse osmosis desalting methods and can be used for the desalination of highly mineralized waters with a high boron content to obtain purified drinking water quality and can be used in water treatment systems.

There is a method of desalination of highly mineralized, in particular sea, water (Patent KI 2142912 C1, 12.20.1990), which includes the evacuation, heating, evaporation of water and condensation of water vapor, in which water is heated and evaporated on one side of the wall of a flat heat pipe, and condensation obtained water vapor on the opposite wall of another flat heat pipe, while periodically spraying between the walls distilled water with a temperature above the temperature of water vapor and carry out a constant effect of electric the magnetic field on the water vapor between the flat heat pipes, and the vacuum is carried out with a height difference of at least 10 m at normal atmospheric pressure. The disadvantage of this method is the complexity of its implementation, due to the large number of specialized equipment and high energy costs.

There is a method of desalination of saline water (Patent KI 2089511 C1, 09/10/1990), using the reverse osmosis method. The disadvantage of this method is the high power consumption and multistage process. As a prototype, a method of desalination of highly mineralized water using membrane technology of reverse osmosis was chosen (Karelin FN. Desalination of water with reverse osmosis. - M: Stroyizdat, 1988 - 208 s). The disadvantage of this method is a complex hardware implementation of the process, leading to a large consumption of electricity and reagents for desalination and removal of boron to sanitary standards. The technical task of the present invention is to simplify the technology of desalination and boron removal of highly mineralized water, reducing the cost of electricity and chemicals during desalination and removal of boron to drinking norms. The technical result is achieved by using one stage of reverse osmosis, where the source water is supplied to membrane modules using high-pressure sea membranes with high boron selectivity, which concentrate is fed to membrane modules using low-pressure high-selective membranes for brackish water, and purified water ( permeate) of any of the membrane modules, except the first, can be directed either to the consumer into the stream of drinking water quality, or to the head of the technological process To improve the quality of the source water.

FIG. 1 is a schematic flowchart of the method that works as follows: source sea water, with a pump (9) is fed to a protective micron filter (8) and further to a high-pressure pump (1). The pump (1) supplies the initial water to the membrane modules of the first stage (2), after which the concentrate of the first stage goes to the membrane modules of the second stage (3), then the concentrate of the second stage goes to the membrane modules of the third stage (4), then the concentrate of the third stage comes on membrane modules of the fourth stage (5), after which the concentrate of the fourth stage is discharged into the drainage. The purified water (permeate) of the first and second stages always has a low boron content, therefore it forms a stream of potable quality water supplied to the consumer. The content of boron in the permeate of each subsequent stage increases due to the sequential concentration of boron in stages. To prevent clogging of the potable-quality water flow by the permeate, which has a high content of boron in any modes, the third stage permeate goes to the three-way valve (6), and the fourth stage permeate to the three-way valve (7). With a low boron content in the third or fourth stage permeate, each of the three-way valves delivers the permeate of the corresponding stage to the potable quality water stream. With a high boron content in the third or fourth stage permeate stream, a three-way valve of the corresponding stage directs the permeate stream to the source water stream. The return of permeate flows to the source water allows not only not to clog the flow of potable quality water with a permeate with a high boron content, as it happens in traditional schemes, but to improve the flow of potable quality in terms of boron content. This is achieved by the fact that the quality of permeate of any stage is ten or more times better than the quality of the source water and the addition of permeate to the source water improves the quality of the source water, which in the process of desalination leads to an improvement in the quality of drinking water.

An option is possible when it is necessary to increase the overall selectivity of the membranes for boron. Then it is possible to use low-pressure, highly selective membranes for brackish waters only in the last stage.

As a result of the use of one desalination stage, as well as in the integrated use of high-pressure and low-pressure membranes, energy is saved by creating a low working pressure on the membranes. Chemical reagents are not used.

The use of this method for the desalination and purification of highly mineralized water from boron avoids the construction of the traditional two-stage reverse osmosis scheme, where low-pressure membranes are used in all stages and stages, there are large electricity costs for two stages of desalination and pumping water from the first stage to the second and a large amount chemical reagents.

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Claims (1)

CLAIM The method of desalination and purification of highly mineralized water from boron to the standards of drinking quality by the method of reverse osmosis, characterized in that one stage of desalination is used, where the source water is supplied to the membrane modules using high-pressure sea membranes with high selectivity for boron to produce water as a permeate drinking quality, and the concentrate is sent to the membrane modules of the subsequent stages, using low-pressure high-selective membranes arranged in a cascade, with the end ntrat from previous steps sequentially fed to membrane modules subsequent steps, the treated water (permeate) of any of the membrane modules, other than the first and second step may be sent to the consumer or drinking water stream, either in the head manufacturing process to improve the quality of the source water.