Membrane desalination plant. Well desalination

Desalination of sea water was made possible by the reverse osmosis method. Desalination systems effectively remove salts, soften water, making it suitable for drinking and industrial use. Our company offers AQUALINE OS seawater desalination plants, which we design and manufacture in our own production. The cost of the equipment is quite acceptable, which makes it affordable both for small enterprises and large companies.

The principle of operation of reverse osmosis sea water treatment plants "AQUALINE OS"

As part of any desalination system - semipermeable membranes. These high-tech devices are entrusted with the function of a molecular sieve, with which they cope perfectly, freeing water from salts, minerals, organics, as well as harmful bacteria and viruses. The process itself is as follows. Water is supplied to the membranes under high pressure. Membranes are designed to pass only water molecules. Large molecules of various substances and compounds are delayed, forming a saline solution, which is discharged into the sewer. The output is clear water.

Advantages of our AQUALINE OS industrial desalination plants

• High performance
    Each system is equipped with a high pressure pump, which greatly increases the efficiency of operation and productivity.
• Ability to clean the membrane
    Over time, the membrane becomes clogged, but this does not require replacement. It is enough to carry out an operation to restore permeability to return the equipment to its original operational characteristics.

Why more and more customers are acquiring AQUALINE OS water desalination systems at LLC First Water Company

• Affordable cost
    The price of the installation includes only the costs of materials and production. All manufacturing steps are carried out directly in our production. In addition, we are suppliers and do not cooperate with intermediaries. These factors determine the low cost.
• Additional services
    Our staff is only experienced and highly qualified employees in the person of engineers, designers, technologists and production specialists. This allows us to develop serious projects, successfully implement them, provide customers with launch and maintenance services.

How to buy an industrial system of water purification "AQUALINE OS"

There are 2 ways to order remotely. You can fill out and send an application through the website or call the phone number in Moscow 8 800 250-96-87. Our operators will tell you in detail about all stages of the acquisition and advise on additional services.

Desalination, a method of treating water to reduce the concentration of dissolved salts to a degree (usually up to 1 g/l), in which water becomes suitable for drinking and household purposes. There is a shortage of fresh water in more than 40 countries, located mainly in arid as well as arid regions, which make up about 60% of the entire surface of terrestrial land (according to estimates, by the beginning of the 21st century it will reach 120-150 · 10 9 m  3 per year). This deficit can be covered by desalination of salted (salinity of more than 10 g/l) and brackish (2-10 g/l) oceanic, marine and groundwater, whose reserves account for 98% of all water on the globe (see also Water resources ) A shortage of fresh water can be eliminated by supplying it through pipelines or channels from areas in which it is in excess. For example, the Seversky Donets-Donbass canals were built in the USSR (about 130 km), Irtysh - Karaganda (about 460 km), 3 lines of the largest in the world Karakum Canal there are (in the Kazakh SSR) water pipelines Ishim and Bulavinsky, with a length of more than 1700 km  each. However, with significant removal of freshwater sources, desalination of salt water in place is cheaper than fresh water entering through water pipelines. With water consumption up to 1000 m 3 /day  Desalination of salt water in place is more profitable than supplying fresh water to a distance greater than 40-50 km, with water consumption of 100,000 m 3 /day- more profitable than supplying fresh water at a distance greater than 150-200 km.

Worldwide in 1974 was in operation St. 800 large stationary desalination plants (OS) with a total capacity of about 1.3 million m 3 /day  fresh water. The largest of them have a capacity of 160 thousand. m 3 /day  (in the city of Shevchenko, USSR; heat comes from a nuclear power plant with a fast neutron reactor) and 220 thousand m 3 /day  (in Kuwait City, Kuwait; OU boiler house runs on associated gas from oil production). Most ships have their own OS (distillation type only).

O. century can be carried out as with a change in the state of aggregation of water ( distillation , freezing), and without changing its state of aggregation (electrodialysis, hyperfiltration, or reverse osmosis, ion exchange, water extraction with organic solvents, water extraction in the form of crystallization water of crystalline hydrates, heating water to a certain temperature, sorption of ions on porous electrodes, biological method - using the ability of some algae to absorb salts in the light and give them in the dark, etc.). In accordance with the methods of O. century. There are various types of opamps. Distillation OSs (single-shell and multi-shell, according to the desalination method - vapor compression and solar) are used for desalination of sea water and salt water. O. century electrodialysis and hyperfiltration (reverse osmosis) economically with a salt content of 2.5-10 g/l, ion exchange - less than 2.5 g/l. Of the total volume of desalinated water received in the world, 96% is accounted for by distillation DUs, 2.9% by electrodialysis, 1% by hyperfiltration, and 0.1% by freezing and ion-exchange DU. Depending on the performance, the OS consists of one or more desalination plants connected in parallel.

Distillation desalination plants are single-stage ( fig. one ), multi-stage with tubular heating elements, or evaporators ( fig. 2 ), multi-stage with instant boiling ( fig. 3 ) and vapor compression. A multi-stage evaporator consists of a series of sequentially operating evaporation chambers with tubular heating elements. Heated salt water moves inside the tubes of the heating element, heating steam condenses on their outer surface. The heating and evaporation of water in the first stage is carried out by the steam of a boiler operating on a distillate; the heating steam of the next stage is the secondary steam of the previous evaporation chamber. In desalination boilers with instant boiling, salt water passes sequentially, from the last to the first, through condensers built into the evaporation chambers, heated by condensation heat, enters the head heater, heated above the boiling point of water in the first evaporative chamber, where it boils. Then the steam condenses on the surface of the condenser tubes, and the condensate flows into the pan and is pumped to the consumer by the pump. Unevaporated water flows through a water trap into the next lower-pressure chamber, where it boils again, etc. Heat consumption for receiving 1 kgfresh water in a single-stage distillation desalination plant is about 2400 kj; Phase transition heat recovery in a multi-stage desalination plant reduces heat consumption by 1 kgfresh water up to 250-300 kj.

Electrodialysis Desalination Plant ( fig. four ) is a multi-chamber filter-press type apparatus consisting of chambers bounded on one side by a cation exchange membrane and, on the other, by anion exchange membrane. The cameras are placed between the cathode and the anode, to which a constant electric current is supplied. Desalinated water enters the desalination chambers. Under the influence of an electric field, cations of salts dissolved in water move in the direction of the cathode, anions - in the anode. Since cation exchange membranes are permeable in the electric field to cations, but impermeable to anions, and anion exchange membranes are permeable to cations, but impermeable to cations, salt water in desalination chambers is desalinated, while the salts removed from it are concentrated in brine chambers, from where they removed together with salt water. Electricity consumption on O. century. electrodialysis depends on the salinity of the desalinated water (2 tue· h  on 1 l  with desalination of water with a salinity of 2.5-3 g/l  and 4-5 tue· h  on 1 l  during desalination of water with a salt content of 5-6 g/l).

Hyperfiltration desalination plants consist of a high pressure pump (5-10 Mn/m  2, or 50-100 bar) pumping salt water through flat or tubular membranes or a hollow fiber made of cellulose acetate or polyamide resins capable of passing water molecules under a pressure higher than osmotic but not passing hydrated ions of salts dissolved in water.

In deserted southern areas and on waterless islands, solar desalination plants are used; they give in the summer months around 4 l  water per day from 1 m  2 surface, perceiving solar radiation.

Lit .:  Apeltsin I.E., Klyachko V.A., Desalination of water, M., 1968; Pavlov Yu. V., Desalination of water, M., 1972: Slesarenko V.N., Modern methods of desalination of sea and salt waters, M., 1973, Spiegler K. S. [e. d.], Principles of desalination, N. Y. - L., 1966.

Water desalination  - a method of treating highly saline water in order to reduce or completely remove salts dissolved in it.

The lack of fresh water is already felt in many countries around the world. In the USSR, a shortage of fresh water is felt on the territory of Turkmenistan, Kazakhstan, Uzbekistan, Azerbaijan, in a number of districts of the North Caucasus, Ukraine, Western and Southern Siberia, the Urals, and the Volga region, where it can be largely covered by desalination available in these regions - on significant resources of highly mineralized groundwater or sea water.

O. century is carried out either by separating the actual water molecules, or by removing salt ions from the solution. Based on these features, desalination methods are divided into two groups: with and without changing the state of aggregation (phase) of water. The first group includes thermal desalination (distillation) and processes using cold (freezing), the second - chemical, membrane, extraction and adsorption, as well as biol, methods.

The most common methods of O. century. are distillation, freezing, electrodialysis, reverse osmosis and ion exchange.

The distillation method (see) is based on the fact that when the water is heated, its molecules, due to thermal and vibrational motion, acquire enough energy to overcome the forces of intermolecular attraction, and the resulting vapor during subsequent condensation gives desalinated water. According to the nature of boiling and design features, desalination boilers, adiabatic (low-temperature boiling in vacuum), thin-film, hygroscopic, hydrophobic, and thermal diffusion are distinguished. The use of distillation is most economical in the desalination of salt (sea) water to produce a significant amount of fresh water.

Desalination by freezing (natural and artificial) is based on using the difference in freezing temperatures of fresh (0 °) and brackish water with a salinity of up to 10 g / l (-1.6 °). The method of natural freezing is used in districts with a cold climate. Artificial freezing involves cooling water by introducing a hydrophobic refrigerant (butanes, freons) directly into desalinated water, evaporating the chilled water in a vacuum, and using water with a lower temperature as a refrigerant. Theoretical calculations show that the method of freezing may be one of the most economically viable. However, technol, difficulties, the large metal consumption of desalination plants and the high consumption of desalinated water in the technological process of such desalination delay the industrial implementation of this method.

The electrodialysis method (electrochemical) is based on the transfer of ions of salts dissolved in water in an electric field between electrodes immersed in desalinated water; while cations move to the cathode, and anions to the anode. To prevent a reverse reaction, cationic and anion-selective membranes are installed near the electrodes, which do not pass oppositely charged ions. The electrodialysis method is most suitable for desalination of brackish water (with salinity up to 10 g / l).

The reverse osmosis method is based on creating a pressure in the system with porous synthetic membranes that exceeds the osmotic pressure; in this case, water molecules are filtered through membranes and salt retention.

The ion exchange method is based on sequential filtering of water through filters loaded with cation and anion exchange resins - ion exchangers (see). The desalination process takes place in two successive stages: the removal of cations and anions. The method is most promising for desalination of low-saline water (with salinity up to 2.5 g / l).

Depending on the desalination method, specific gig are installed. conditions of use and operating modes of desalination plants, including methods for preliminary preparation of source water, its additional purification, correction of salt composition, disinfection and conditioning of desalinated water, as well as conditions for the use of structural and technol, materials and reagents.

Water obtained by various desalination methods must comply with the current state standard for drinking water (see Water, sanitary and hygienic requirements), as well as be physiologically complete. Drinking pure distillate for drinking purposes adversely affects the state of yellow-quiche. tract and water-salt metabolism of a person. According to the "Methodological guidelines for hygienic control of the design, construction and operation of group agricultural water supply systems" No. 2058-79, approved by the USSR M3, the minimum necessary level of mineralization (100 mg / l) and the optimal levels of mineralization of desalinated drinking water of chloride-sulfate are accepted (200-400 mg / l) and bicarbonate (250-500 mg / l) classes. The minimum calcium level (1.5 mg same / l), maximum (6.5 mg - equiv / l) and minimum (0.5 mg - equiv / l) allowable alkalinity levels, minimum hardness level are also regulated (1, 5 mg - equiv / l), the maximum permissible concentration of boron (0.5 mg / l) and bromine (0.2 mg / l).

Bibliography: Apeltsin I.E. and Klyachko V.A. Desalination of water, M., 1968; Rakhmanin Yu. A. et al. Experimental and clinical-physiological materials for substantiating the lower limits of mineralization of desalinated drinking water, Gig. and dignity., No. 7, p. 16, 1975; Sidorenko G. I. and Rakhmanin Yu. A. Desalination as a hygienic problem in the USSR, ibid., No. 12, p. 14, 1977.

G.I.Sidorenko.

Desalination by freezing is a new method, the development of which began in the second half of the 70s. At present, detailed studies of various processes are being carried out, as a result of which three types of freezing processes are distinguished: upon contact of salt water with a heat transfer surface cooled by a refrigeration unit; upon evaporation of chilled water in a vacuum; and in direct contact of water with a refrigerant that is not miscible with water. The main stages in desalination plants of all three types are crystallization-ice formation; separation of ice and brine and washing of ice from brine; and melting ice. In plants of the third type, the process of separating the refrigerant and fresh water is added. [...]

Desalination of water by reverse osmosis (hyperfiltration) occurs without phase transformations. The energy in this case is mainly spent on creating the pressure of the source water - the medium is practically incompressible. The osmotic pressure of solutions that are close in composition to natural waters, even with a small salinity, is high enough, for example, for sea water containing up to 3.5% salts, it is about 25 at. It is recommended that the working pressure in desalination plants be maintained at least 50-100 at and even higher, since their productivity is determined by the difference between the working and osmotic pressures. [...]

Desalination consists in the complete or partial removal of dissolved salts from sea or any other salt water. Desalination is currently used in the production of demineralized water for industrial chemical processes and, in limited quantities, for human production in anhydrous areas (for example, in areas adjacent to the Arabian Sea and on some islands in the Caribbean). With the growing population in the United States, the need for fresh water has also increased to such an extent that they cannot be satisfied only with natural fresh water supplies. Thus, desalination becomes a very important way to obtain fresh water. [...]

When desalinating the water of open seas, the task of removing brines is easier. In the case of their dispersed discharge into the sea, one can not be afraid of any significant negative consequences. Discharge of brines is also possible with the construction of desalination plants on the shores of the inland seas (Caspian or Azov). [...]

We encounter ideas of desalination in the “Natural History” of Pliny the Elder (23 or 24-79), an ancient historian who lived in the 1st century AD. n e. He describes two desalination methods. The first, oldest, is that the fleece (sheep's skins), hung overnight overboard the ship, absorb moisture, and in the morning it can be squeezed, thus obtaining fresh water. The second method is described by him as a legend with a long history. Its essence is to obtain fresh water inside a wax ball, lowered into the sea. However, neither the author of the Natural History, nor other researchers who turned to the history of desalination failed to find experimental confirmation of this “method” [...]

Typically, when desalinating water, amines (diisopropylamine, triethylamine, mixtures of the latter with diethyl methylamine), alcohols (butyl, etc.), ethers, etc. are used as extractants. Triethylamine is one of the best solvents in terms of extraction properties and economy. The diagram of the mutual solubility of triethylamine and water of different salinity is shown in Fig. 273. [...]

Salts dissolved in water are removed by distillation, electrodialysis, ion exchange, and reverse osmosis. Distillation is the process of converting incoming water to water into water vapor, which then condenses. Distillation is one of the methods used to desalinate sea water. Electrodialysis consists in the separation of positive and negative ions by means of selective membranes, which, when passing a direct electric current, pass ions from the treated solution located on one side of the membrane to the concentrated solution located on the other side of the membrane. The problems arising from the electrodialysis method of desalination are associated with the chemical deposition of poorly soluble salts and clogging of the membrane with colloidal masses. To prevent clogging of membranes, desalinated water from surface sources must undergo preliminary treatment (chemical precipitation and purification using activated carbon to extract molecules of organic substances and colloids from water). Desalination by ion exchange is described in clause 7.9. Due to the high cost of these processes, apparently, none of them will find wide application in the practice of water purification. [...]

The salt composition of water. Under the salt composition of water is understood as a combination of mineral and organic compounds dissolved in it. Depending on the amount of dissolved salts, fresh water is distinguished (up to 0.5% o) (% o - ppm - salt content in g / l of water), brackish (0.5-16.0% o), sea (16-47 % o) and salted (more than 47% o). Sea water contains mainly chlorides, and fresh water contains carbonates and sulfates. Therefore, fresh water is hard and soft. Too desalinated, as well as saline, water bodies are unproductive. Salinity of water is one of the main factors determining the habitat of fish. Some fish live only in fresh water (freshwater), while others live in marine (marine). Passing fish replace sea water with fresh water and vice versa. Salinization or desalination of water is usually accompanied by a change in the composition of the ichthyofauna, food supply, and often leads to a change in the entire biocenosis of the reservoir. [...]

When choosing a method of desalination and desalting of water, one should take into account: the salt content of the source water, the desired performance of the desalination plant, as well as the cost of heat sources, electricity, and the required chemical reagents and materials. In practice, there is a need for desalination of water with a total salinity of 2,000 to 35,000 mg / l. [...]

The use of atomic energy is very promising for desalination. Work in this direction is already underway. At present, a fast neutron reactor is being built on the shore of the Caspian Sea in the USSR, which will be combined with a distillation desalination plant. In the US, it is planned to build this type of station with a capacity of 150-750 Met, having a desalination plant with a capacity of 225-675 thousand m3 / day. [...]

The process of removing salts from water, depending on the degree of their extraction, is called desalination or desalination. When desalinating water, the concentration of dissolved salts is brought to a limit close to their content in fresh waters, and when desalted, to their content in distilled water. [...]

The high cost of the desalination process is the main disadvantage and an obstacle to its widespread adoption. Freshwater is traditionally one of the cheapest products and sold at a price of a few cents per ton. The price of water obtained by any of the desalination methods is several times higher than the cost of natural water in industrial areas of the United States. Studies conducted in the 50s and 60s led to a decrease in the cost of distilled water from 1.30 in 1950 to 0.23 dollars / m3 in 1974 (for comparison: the cost of natural fresh water in US cities is 0.05 dollars / m3). [...]

Water to be purified is supplied to the central chamber. When the current is turned on, ions penetrate through the diaphragms into the cathode and anode spaces. Their back diffusion is complicated by diaphragms. The desalination apparatus consists of ten cells connected in series. Water Fig. 62. [...]

Of considerable interest is the desalination of water by the method of electroadsorption of ions by porous electrodes. It is based on the fact that the formation of double electric layers on oppositely charged inert electrodes from a direct current source having a highly developed surface is accompanied by the extraction of very significant amounts of dissolved salt. [...]

Israel uses a desalination plant for vacuum freezing. Pure ice crystals are formed in saline at the same time as part of the liquid evaporates. These ice crystals are then separated from the solution and washed. The washed crystals are brought into contact with the compressed steam. As the vapor condenses, the ice melts. One of the advantages of this system is the very low energy consumption of -11-14 kWh per 1 m3 of water produced, and with the improvement of the design, this figure can easily be reduced to 7-9 kWh per 1 m3. The Israeli installation consists of four blocks each with a capacity of 10 m3 / h. It processes water taken from the Red Sea with a salt concentration of 4.2%. Each block consists of two adjacent cylindrical vessels with a diameter of 4 m. One acts in the washing mode, the other as a freezer and thawer. Under the dome of the unit there is a steam compressor that draws water vapor from the freezer and compresses them, then they enter the thawer, and the ice goes down the gutter. [...]

We have already talked about the history of desalination, and it was easy to notice that its development was primarily associated with the fleet. By the 60s of our century, many technical problems had already been solved for obtaining large quantities of desalinated water on ships. [...]

The most important requirements for extractants for desalination of water are high selectivity (water dissolved in a solvent should contain significantly less salts than the undissolved part of water), high extraction capacity, sensitivity of mutual solubility in the water - extractant system to temperature, low solubility of the extractant in water, ease of its regeneration, a sufficiently large difference in the densities of water and extractant, stability of the extractant when interacting with aqueous solutions of salts, etc. Of the known solution For example, secondary and tertiary amines with four to six carbon atoms in a molecule possess the best extraction properties [...]

A more promising membrane technology for desalination of high salinity water is reverse osmosis (hyperfiltration). This desalination method is based on the phenomenon of osmotic transfer, i.e., filtering water through a set of semipermeable membranes that pass water molecules but trap salt ions. The essence of the process can be represented as follows. If solutions of different concentrations are separated by a semipermeable membrane, then water molecules will move towards equalization of concentrations, i.e., from more fresh water to more salty. This transition will be observed until the concentration of solutions on both sides of the membrane becomes the same. However, the volume of initially more salty water will increase. The difference in water levels on both sides of the membrane, corresponding to the equilibrium concentration, characterizes the osmotic pressure. It is quite obvious that for desalination of salt water it is necessary to direct the process to the other side. [...]

After all, we are dealing with rather energy-intensive production, requiring the investment of significant material resources. At first glance, this is so. Nevertheless, in many countries they already make substantial material costs, solving the problems of providing for the population and developing the economy with the help of desalination. These costs, as you can see from the examples we gave earlier, are justified. It is also important that the improvement of distillation desalination technology constantly takes into account the economic side of this process, reducing the cost of the produced water from year to year. Similarly, membrane technology is developing now. [...]

This book does not examine in detail the methods of desalination of water that change its state of aggregation ‘. Note that at present, with a high salinity of water, distillation desalination plants are most widely used. Their main function is the evaporation of water followed by condensation of steam, which leads to the production of fresh water. [...]

But, whatever Kerodren argued, the attitude of sailors to desalinated water has not changed. [...]

Such a filter, it would seem, made it possible to enrich desalinated water with calcium and chlorine ions, to some extent hydrocarbonate, carbonate, and sulfate ions, which should have made mineralized water more saturated in chemical composition. Magnesium ion enrichment in this case was not provided, although its content in natural waters is quite high. [...]

Yub.Rozval K.S. Features of the effect on the human body of desalinated waters of varying degrees of mineralization // J. Hygiene and sanitation. 1971. No 8. [...]

For its needs, mankind mainly uses fresh waters, which make up 1% of the total hydrosphere. To solve this problem, desalination of water of the World Ocean, groundwater and glacier water should be involved (desalination plants of Komsomolets JSC - food tin). Due to the high cost and high energy intensity of desalinated plants, the share of desalinated water in the total water supply is insignificant (USA - 7%, ours - 1%). [...]

The best hydrate-forming substances used for desalination of water are propane С3Н8 and fluorochloride derivatives of fatty hydrocarbons - freons. These substances are non-toxic and are simultaneously used as refrigerants to maintain the temperature necessary for hydrate formation. So, Freon-12 (difluorodichloromethane CF2C12), having the so-called bale. -23.7 °, forms a gas hydrate with structure II with water. When using propane (t. Kip. -42, C), forming a gas hydrate with structure II, desalination is carried out at 2-5 ° C and a pressure of up to 500 kPa. The temperature and pressure ranges at which the formation of gas hydrates is possible depends on the salinity of the water. Since the formation of gas hydrates is accompanied by the release of heat, it is necessary to cool the system during crystallization. To accelerate the formation of germ crystals, the gas-water mixture is supercooled. The resulting gas hydrates retain a layer of brine on the surface of the crystals, so after separation they must be washed with desalinated water. [...]

Thus, when approaching the choice of a sprinkler composition for giving desalinated water drinking qualities, one could proceed from the sum of hygiene knowledge known at that time about the rationing of chemicals in drinking water, the biological role of individual micro- and macro-components of water, which determine both organoleptic and physiological its properties. [...]

The essence of the method is that when direct current passes through water, ionite membranes with selective ability to pass ions with a certain charge sign are placed on the path of directed ion movement. As a result of this, desalination of water occurs in one part of the cells formed by the membranes, and the concentration of salts in the other [...]

A certain modification of the described crystallization process is the desalination of water by obtaining propane crystalline hydrates. The first step is to bind a portion of the water of the saline to crystalline propane hydrates. Then the crystals are separated from the mother liquor, they are cleaned from brine and, finally, the crystals are melted to produce fresh water. [...]

The degree of elaboration of various technological processes of wastewater treatment is not the same. Some of them are at the experimental stage, while others are at pilot industrial tests. The most developed is the reverse osmosis membrane method of desalination and desalination of water with bringing salinity to the level of drinking water (500 mg / l). Thousands of reverse osmosis desalination plants are currently in operation in the world. This example of the large-scale implementation of the membrane method for water purification testifies to the reality of refinement to widespread use of other methods close in technological processes. Membrane wastewater treatment methods have also proven themselves in small installations (stationary and mobile), on ships and offshore platforms. [...]

The desalination plant consists of a block of electrodialyzers, pumps, desalinated water tanks (diluate), brine tanks (concentrate), an acid tank, a polarity reversal unit and a control panel. [...]

The schematic diagram of the installation, which is the same for all possible technological options for desalination of water by the method of ion electrodesorption, is shown in Fig. 347. In order to avoid decomposition of water and adverse redox reactions on the electrodes, the adsorption process is carried out at a voltage of not more than 1.5 V. Desorption of absorbed ions (regeneration of electrodes) is carried out by switching the polarity of the electrodes. During the regeneration period, adsorbed ions pass into the salt water discharged into the drainage. [...]

Separate stages of research and development work on the creation of desalination water of increased mineralization, carried out in our country, were discussed in the USSR State Committee on Science and Technology at the level of temporary scientific and technical commissions. Such commissions, including highly qualified specialists from various departments, were convened in 1970 and 1978. Their function was mainly to develop a unified technical policy in the field of desalination and desalination of water. This approach was based on an assessment of the global scientific and technological level of the existing desalination technology and its development trends in foreign countries. Key technical problems were also identified in the field of desalination of high salinity water in the USSR, and the main ways to solve them were outlined. At the same time, much attention was paid to membrane technology. [...]

Desalination plants ordered, which will be produced on about. Aruba another 10 thousand tons and on about. Curacao - 4 thousand tons of fresh water per day. On both islands, fresh water is a byproduct of power plants because the heat of the spent steam is used to desalinate water. The combination of a power station and a desalination plant is the result of many years of work by Weir. Installation on about. By the time this book was published, Curacao had worked at full capacity for 26,000 hours (three years) and had no scale. [...]

Currently, the most studied agent is propane, the use of which is the basis for the desalination of water by the hydration method, shown in Fig. 280. [...]

Installations of the first type are small containers with a light-absorbing bottom, filled with salt water. Above them, an inclined ceiling of glass or transparent plastic is installed (Fig. 327 and 328). Water vapor, cooling due to colder atmospheric air, condenses on the inner surface of the installation; drops of desalinated water flow into the peripheral trays. Depending on the design and materials used, the performance of desalination plants of this type in the conditions of the Central Asian republics reaches 10 liters of water per day from 1 m2. [...]

The main water discharge zone is confined to the south-Stavropol uplift zone (Ubezhenskoye field), where there are favorable conditions for the flow of water into overlying deposits. Variegated waters with a salinity of less than 10 g / l are common here. Within the Tersko-Caspian trough, the Nogai step and partially the Chernoles depression, an AVPD zone is distinguished, which is characterized by a predominance of water with a salinity of 35-60 g / l. In the lower part of the Upper Cretaceous complex, waters of increased mineralization are often found (60-90 g / l, gaa / gC1 0.8-0.97). Such a change in water mineralization along the section of the complex is associated with the influx of desalinated water from overlying clay deposits of the Paleogene during their compaction. [...]

At present, large-capacity electrodialysis units have been developed and are in operation for desalination of fresh water. So, the work reports on the results of the commissioning of an electric plating installation with a capacity of 250 m3 / h for desalination of water with a salinity of 500-2000 mg / l. The installation consists of two modules with 300 pairs of cells measuring 1500X1500 mm. The equipment of the installation is made of plastics. Water undergoes preliminary decarbonization on weakly acid cation exchanger and softens on strongly acid cation exchanger. The weakly acidic cation exchanger is regenerated by HC1, and the weakly acidic cation exchange resin is also HC1, but with the addition of a part of the brine from the electrodialyzer. Energy consumption was 1.77 kWh / m3. The decrease in salt content averaged 40% of the original. [...]

Electrodialysis desalination plants are divided into direct-flow and circulating. In single and multi-stage direct-flow installations, the specified desalination of water occurs during its flow through the bath cells. In circulating water, desalinated water is passed through the cells of the bath until the salt content in it drops to a predetermined value; they are of batch and continuous action. The choice of installation is based on technical and economic calculations. [...]

This question is not new. It arose almost simultaneously with the advent of distillation apparatuses intended for marine vessels. And the sailors themselves asked him first. Desalinated water was tasteless. She did not quench her thirst, caused discomfort. The sailors refused to drink it. In the XVIII century. Distillation cubes on ships established the French Ministry of the Navy. And it was this department that was the first to respond to the complaints of sailors. For the experiment, prisoners were selected. On the island of Aene, in the middle of the Rochefort port raid, six people were detained for 30 days. The only water to drink was the distillate. None of the prisoners died, apparently everyone was healthy. And on December 29, 1817, the inspector general of the French fleet, Kerodren, published an article in the “Monitor” that completely rehabilitates desalinated water. [...]

Industrial electrodialysis units consist of a large number of parallel-running chambers. In multi-chamber installations, brine chambers and desalination chambers (working dilution chambers) are formed by alternating cationic and anionic membranes. The former let cations pass into the electric field, but delay the anions, the latter, on the contrary, pass the anions, but delay the cations. [...]

The hydrate separation unit is in many ways similar to the URUS unit (see X1X-21). The hydration reactor replaces the URUS freezer. Salt water and hydrating liquid are injected into this chamber at certain pressures and temperatures. Part of the hydrating agent is converted into steam and, upon absorption of heat, causes the formation of hydrated crystals. The crystals are then washed from the brine and sent to the melting chamber, where the heat necessary for melting is obtained by condensation of the compressed steam from the reactor. The main problem, as in the YaRUS system, is the problem of separating desalinated water and part of a hydrating agent. In this system, the melting chamber is located outside the reaction vessel, in contrast to the URUS system, where it is placed in a combined cell (hydroconverter). [...]

Excess propane exiting the main compressor is further compressed in the secondary compressor, then condensed in the heat exchanger upon cooling with desalinated water and supercooled by stock brine and source seawater. Subcooled propane, entering the reactor, instantly evaporates, compensating for the heat loss of the reactor system. The obtained fresh water and brine pass through turbines designed to return part of the energy spent on driving the sea water supply pumps. [...]

Siberian vendace in the territory of Yakutia is the main commercial species in all rivers flowing into the seas of the Arctic Ocean. The vendace spends a significant part of its life in the desalinated waters of the coastal zone and near-shore areas, i.e. on the shelf. The basis of fishing is made up of mature individuals with a long body (ac) 270-350 mm, usually 300-330 mm, weighing 100-250 g. For the period 1991-1999. the annual catch of vendace in the reservoirs of Yakutia averaged 750 tons. [...]

Oztegiv and Meeorie, with the exception of their residential freshwater forms, are typical inhabitants of brackish waters, not leaving far from the coast inland. Capelin is already a typical pelagic fish, spending a significant part of its life in the sea, where it is often observed by whalers when it jumps out of the water when chasing whales. [...]

This method is based on the filtration of solutions under high pressure through suitably prepared cellulose acetate membranes on porous pipes. In this case, the filtrate has a significantly lower concentration of dissolved substances than in the initial solution. The method of desalination of water by hyperfiltration is based on the filtration of salt water through semipermeable membranes that allow water to pass through but retain hydrated ions of salts dissolved in water. [...]

In 1907, on the Arabian coast of the Red Sea, in Jeddah, which was part of the Ottoman Empire at that time, two directors were established. They worked-on solid fuel. In 1928, they were replaced by more advanced evaporators with submersible pipes with a fresh water capacity of 135 m3 / day each. For this city, the use of desalinated water to this day is an essential element of life support. The memory of his first desalination plants is preserved by original sculptures mounted from their parts. [...]

At low tide, the soil dries up significantly and the salt content in it increases several times. Mangrove trees have an amazing ability to tolerate large fluctuations in the concentration of salts (mainly sodium chloride) in the soil. Their roots ensure the desalination of desalinated water by ultrafiltration, as shown by the research of P. F. Sokoladera conducted in 1968. The liquid entering the vessels of mangrove wood contains only about 0.03% salt. Nevertheless, salt accumulates in tissues, especially strongly in old leaves due to prolonged transpiration. [...]

However, none of these methods of removing residual brines can be considered as universal, suitable for any area. Moreover, the disposal of wastewater from desalination plants, even with their low productivity in a number of places, becomes a difficult task, the solution of which sometimes depends on the very possibility of desalination of waters of increased mineralization. [...]

It should be noted that in freezing and gas hydrate units with direct contact devices, the highest heat and mass transfer coefficients are achieved with a small heat pressure, which can significantly reduce energy costs and, consequently, investment in equipment. When using these desalination processes, there is no intense corrosion of materials and scale formation. Since gas hydrate installations did not pass the operational test, the economic estimates of the method presented in the literature can be taken as indicative. According to available data, energy costs during desalination using Freon-31 will amount to 4.5 kWh per 1 m3 of fresh water. [...]

Promising hydrate-forming gases are propane and various types of freons. With a relatively small excess pressure and temperatures above 0 ° C, conditions are created for the precipitation of gas hydrates in the form of a light snow-like mass. Subsequent washing of the crystals from the brine, the evolution of gas and its return to the cycle makes it possible to obtain desalinated water from solutions with a wide range of salt content. To melt crystalline hydrates, it is possible to use so-called waste heat (waste hot water, exhaust gases, low-grade steam) in plants of this type. To increase the efficiency of plants, desalination technology is improved in order to simultaneously extract valuable components from brines - for example, magnesium, iodine, bromine, tungsten - and utilize the remaining salts.