RU2554720C1 - Desalination plant and its thermosoftener - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: desalination multistage adiabatic plant additionally comprises a thermosoftener (52) which serves for the generation of sludge particles in the feed water heated in a steam heater (26) and taken from a pipeline to supply the feed water to the inlet of a multi-stage adiabatic evaporator (4), as well as a two-section feed water receiver (76) to reduce supersaturation in the sea water being evaporated due to the usage of sludge particles as "seed crystals" in the supersaturated solution volume. The thermosoftener (52) comprises a perforated membrane (56) built-in in the casing (53) under the cover, a dome-shaped horizontal partition (61) installed with a gap in respect to the inner casing wall, vertical cylindrical shells, a manifold to withdraw the vapour (62) under the dome-shaped partition, a branch pipe for water withdrawal is united with the sludge particle removal and is mounted in the casing bottom, and the branch pipe for steam supply is built-in in the casing cover.

EFFECT: lower rate of scale formation on working surfaces of the plant elements.

2 cl, 9 dwg

Description

The invention relates to the field of desalination of sea water and can be used in desalination plants of stationary and marine design.

As is known in countries with limited natural reserves of fresh water (rivers, lakes, ground and underground sources), for example Saudi Arabia, Kuwait, Oman, etc., as well as on sea vessels, the main source of replenishment of fresh water used for domestic, technological and technical needs, are installations for desalination of sea water. At the same time, the most famous and widespread desalination plants are the thermal distillation of sea water with the sequential organization of heating, evaporation and condensation processes in them.

Currently, multi-stage adiabatic desalination plants using a high-vacuum operating mode are widely used and known as desalination plants of high productivity. The essence of such a well-known adiabatic multi-stage desalination plant is the presence of vacuum evaporation stages produced by using the heat of preheating of sea water relative to the saturation temperature in the corresponding evaporation stage, which is ensured by the use of throttle atomizers of heated liquid in the evaporation chambers with a stepwise decrease in the working pressure of evaporation and subsequent condensation of the secondary steam with the appropriate organization of the distillate discharge .

A common drawback of these widely known adiabatic desalination plants is scale formation on the heat exchange surfaces of an external feedwater heater and secondary steam condensers, in the working channels of the secondary steam separator, as well as in the bypass channels and the throttle atomization of evaporated sea water in the evaporation stages, due to the high content in marine water of scale-hazardous hardness salts (CaCO ₃ , Mg (OH) ₂ , CaSO ₄ ), which have a solubility negative in temperature of heating the liquid, which determines the increase in the degree of supersaturation of the solution for these components with increasing temperature of the heating fluid. Moreover, the presence of natural crystallization centers (wall roughness, contamination, etc.) on the working surfaces of the desalination plant elements providing heating and movement of heated sea water, in combination with overheating of the wall layers of solutions supersaturated with scale-forming salts under conditions of regenerative supply and removal of heat (through heat exchange wall) determines the inevitability of scale deposits on heat transfer surfaces in the process of heating feed water and the condensation of the secondary steam, and e on the working surfaces of the separator vapor and bypass channels and the throttle channel spray solution was evaporated during its movement in sequential stages of the evaporator.

It is well known that the rate of scale formation increases with an increase in the heat stress of heat transfer surfaces, an increase in the heating temperature, and a rate of evaporation of the solution, i.e. is determined by the degree of supersaturation of the solution with scale-forming salts. It is these circumstances that dictated the need to limit the temperature of pre-heating of feed water in an external heater and to use the multi-stage deep-vacuum evaporation of sea water in well-known adiabatic desalination plants in order to ensure an acceptable scale formation rate on the working surfaces of their elements.

Mutually complementary versions of the description of the same ship’s deep 5-stage adiabatic desalination vacuum desalination plant type M5 with a capacity of 240 tons / day, adopted as a prototype [UDC 621.187.12. Kovalenko V.F., Lukin G.Ya. Ship water desalination plants. - L .: Shipbuilding, 1970. - 304 p., Fig. 89, Fig. 90, p. 239-244, as well as a variant of the description of the same author UDC 639.2.061 Lukin G.Ya., Kolesnik N.N. Desalination installations of the fishing fleet. - M .: Food industry, 1970. - 368 p., Fig. 44, Fig. 45, p. 130-135].

This desalination plant includes:

- an external multi-pass (over heated water) shell-and-tube steam feed water heater, having a straight-tube bundle with a dividing wall forming a vapor-air cavity for collecting and subsequent removal of the non-condensed vapor-air mixture, and also equipped with a condensate collector with its level sensor;

- two-stage steam-jet ejector;

- a condenser of a two-stage steam-jet ejector with separate condensation chambers of the air-vapor mixture, respectively, from the ejectors of the first and second stages, which together with the cooling water pipes are connected in series therein, condenser coolers with their condensate collectors connected between themselves by a U-shaped pipe, and also equipped with separate pipes air removal from these condensation chambers;

- pumps (feed, condensate, brine), pipelines, disconnecting and switching automatic valves, control and measuring devices (thermometers, manometers, vacuum gauges, flow meters), automatic control and protection means (straw meters, condensate and distillate level controllers, temperature controllers, etc. .);

- a multistage adiabatic evaporator mounted in a sealed enclosure made in the form of a rectangular parallelepiped and containing vertical dividing walls that form separate evaporation stages, in each of which a two-pass (through cooling water) shell-and-tube secondary vapor condenser having a straight-tube bundle with dividing wall, forming a cavity for the collection and subsequent removal of not condensed vapor-air mixture, and is also equipped distillate collector, and in the middle zone a louver type secondary steam separator is mounted, designed to separate brine droplets captured by rising secondary steam and separating the data of the evaporation stage into the upper zone, which is the condenser and the lower, which is the evaporative one. At the same time, in the lower zone of each evaporation stage, a brine receiver of this evaporation stage is arranged, which is made in the form of an oversized pipe with an increased diameter, with bypass pipes of the throttle-spray device of the subsequent evaporation stage connected to it. Moreover, each of these bypass pipes contains in its upper free part a built-in throttle device, above the upper cut of each of which there is a mushroom-shaped chipper, which acts as reflectors of “fountain” jets of water flowing from the holes of the throttle device, which contributes to the droplet spraying of an overheated brine and creates conditions for its effective evaporation.

All data of the evaporation stage are sequentially communicated among themselves by connecting bypass pipes of the cooling water of the secondary steam condensers and are equipped with pipes of sequential bypass of the resulting vapor-air mixture from the respective cavities of these secondary vapor condensers in the direction from the first evaporation stage to the last, and two adjacent chambers of the evaporation stages are in series connected between in the lower zone bypass pipes from the brine receivers of a given evaporation stage to the throttle evacuation devices of the subsequent evaporation stage.

In this case, the brine receiver of the last evaporation stage is in communication with a pumping brine pump, the pressure pipe of which has a branch jumper with a valve integrated in the pipe in front of the evaporator feed pump, the pressure cavity of which is connected to the receiving pipe of the cooling pipes of the secondary vapor condenser of the last vaporization stage. Moreover, the pressure pipe of the feed pump is equipped with a flow meter, and an overboard water filter is built into its suction pipe.

The multi-stage adiabatic evaporator also contains a system of interstage throttle washers mounted on the mentioned pipes of the sequential bypass of the vapor-air mixture from the secondary vapor condensers. In this case, the vapor-air cavity of the secondary vapor condenser of the last stage of evaporation is in communication with the receiving cavity of the mixing chamber of the first-stage steam jet ejector, the output diffuser part of which is connected with the vapor-air cavity of the condensation chamber of the condenser of the first stage of the steam-jet ejector.

The cavity of the mixing chamber of the second stage steam-jet ejector is connected to the pipe for exhausting air from the condensation chamber of the condenser of the first stage of the steam-jet ejector, and the output diffuser of the steam-jet ejector of the second stage is connected to the vapor-air cavity of the condensing chamber of the condenser of the second stage of the steam-jet ejector equipped with a pipe for exhausting air into the atmosphere.

The inlet nozzle part of both of these ejectors is connected in parallel to the working steam supply pipeline, and the condensate collector cavity of the condenser chamber of the condenser of the first stage of the steam-jet ejector is in communication with the condensate collector cavity of the external multi-pass shell-and-tube steam feed water heater. *

*Note. In the text of the source of the publication of the well-known prototype solution on page 241 (Fig. 89), an explicit typo was made regarding the connection of the steps of the steam jet ejector to the two-chamber condenser of the steam jet ejectors, which makes the system clearly not operable. In this regard, the text of the description of the prototype made appropriate adjustments based on the technical description of a multi-stage steam jet ejector, given in the guidelines for setting up and operating steam jet ejectors of condensation units RD 34.30.302-87 (Fig. 2).

A discharge pipe of the cooling water of the condenser of the condenser of the first stage of the steam jet ejector is connected to the receiving part of the water cavity of the external multi-pass shell-and-tube steam heater whose vapor cavity is also connected to a low-grade source of heating steam and (for example, steam taken from auxiliary turbines) through a steam line with an integrated temperature controller, and this heater itself is made with the cross direction of movement of their mutually heat-exchanging media with a rectilinear direction of movement of the heated stream

The output part of the water cavity of the external multi-pass shell-and-tube steam feed water heater, in turn, by means of a discharge pipe equipped with a temperature sensor connected to a temperature controller by a control pulse integrated in the supply steam of the heating steam, is in communication with the input pipe of the feed water receiver of the first evaporation stage evaporator integrated along the axis of its elliptical bottom, and bypass pipes are connected to the output part of this feed water receiver throttle switching first stage evaporator evaporation.

The distillate collectors of all the secondary vapor condensers are pairwise connected in series with each other by interstage bypass pipes of the distillate, each of which is made in the form of a U-shaped pipe, while the distillate collector of the condenser of the second vapor of the last evaporation stage is connected to the receiving pipe of the distillate tank connected by a pipe to the pumping distillate pump .

Moreover, the mentioned interstage movement of the vapor-air mixture, distillate and evaporated brine is carried out due to the difference in working pressure in adjacent evaporation stages of the evaporator.

The air cavity of the distillate tank is in communication with the vapor-air cavity of the secondary steam condenser of the last stage of evaporation of the evaporator to equalize the pressure in these cavities and the reliable flow of the distillate. Moreover, the distillate tank is equipped with a level sensor communicated by a control pulse with a tank level regulator built into the pressure part of the pumping pipe of the distillate pump to maintain its working level and stable operation of this pump, and a flow meter and an automatic three-way are installed on the output section of the pressure pipe of the pumping distillate pump a switching solenoid valve that switches the pipeline to discharge distillate with its low quality by means of monitor control pulse with a straw meter installed on the measuring branch jumper of the distillate circuit.

The steam-air mixture from the vapor-air cavity of the external multi-way shell-and-tube steam feed water heater is diverted by means of a pipeline to the steam-air cavity of the secondary steam condenser of the first stage of evaporation of the evaporator, and the condensate from the heating steam from the condensate collector of this external multi-pass shell-and-tube steam heater of the feed water is discharged through the pipeline through the pipeline for its reuse in the vapor condensate cycle. At the same time, its condensate collector is equipped with a level sensor communicated by a control pulse with a level regulator installed on the discharge pipe of the pumping condensate pump to maintain the working level in the collection and stable operation of the pump itself, and an automatic three-way switching solenoid valve is installed on the output section of its pressure pipe , switching this pipeline to condensate discharge with its low quality by means of its connection with a control pulse to a straw meter, mounted on the measuring tap of the condensate circuit.

A well-known drawback of this desalination plant (DU) is scale formation on the heat-exchange surfaces of an external multi-pass shell-and-tube steam heater of feed water and secondary steam condensers, on the surfaces of the working channels of louvered secondary steam separators and working elements of the multi-stage evaporator throttle-spraying devices, which reduces its working life.

The mechanism of scale formation is a rather complex process that proceeds at the molecular level, while the fundamental conditions for the onset of scale formation are:

- the presence of supersaturation of scale-forming salts in the wall layers of the liquid or in the volume of the solution, i.e. reaching the solubility limit of hardness salts;

- the presence of crystallization centers on the wall (roughness, scale crystals, various impurities, etc.), or - in the volume of the liquid (vapor bubbles, suspended particles of impurities and formed sludge).

и $$HC{O}_3^{-}$$

обусловливает большую жесткость морской воды, которая доходит до 140 мг-экв/л. При этом в процессе нагрева и упаривания раствора соли жесткости CaCO₃, Mg(OH)₂, CaSO₄, обладающие отрицательной по температуре нагрева жидкости растворимостью, выпадают в виде накипи на теплопередающих и рабочих поверхностях или шлама в объеме раствора при достижении пересыщения раствора по этим компонентам, причем соотношение этих двух форм снижения пересыщения раствора определяется соотношением суммарных поверхностей центров кристаллизации на рабочих поверхностях и в объеме жидкости.The presence of a significant amount of Ca ²⁺ , Mg ^{2+ ions} , $$S{O}_{\mathrm{four}}^{2-}$$

and $$HC{O}_3^{-}$$

determines the high hardness of sea water, which reaches 140 mEq / l. At the same time, during the heating and evaporation of the solution of hardness salt CaCO ₃ , Mg (OH) ₂ , CaSO ₄ , which have a solubility negative in the temperature of heating the liquid, they precipitate in the form of scale on heat transferring and working surfaces or in the volume of the solution when the solution is saturated with these components, and the ratio of these two forms of reducing the supersaturation of the solution is determined by the ratio of the total surfaces of the centers of crystallization on the working surfaces and in the volume of liquid.

X-ray diffraction analysis of scale from evaporators of sea water shows that in general it is formed by three main components: calcium carbonate CaCO ₃ , magnesium hydroxide Mg (OH) ₂ and calcium sulfate CaSO ₄ , and the structure and chemical composition of salt deposits are largely determined by the temperature of the working processes implemented in the OS.

Calcium carbonate is formed by heating from bicarbonate:

Ca (HCO ₃ ) ₂ → CaCO ₃ ↓ + H ₂ O + CO ₂ ↑

The predominant CaCO ₃ content is typical for vacuum evaporators, where the evaporation temperature does not exceed 60-80 ° C. Carbonate scale is characterized by a relatively low density, loose structure and low strength. It is easily dissolved by almost all acids, except oxalic. All these qualities are the result of one property of calcium carbonate - the ability to form crystals (sludge) in the water column.

A similar reaction occurs with magnesium bicarbonate when heated:

Mg (HCO ₃ ) ₂ → MgCO ₃ + H ₂ O + CO ₂ ↑

When water is heated, hydrolysis of magnesium carbonate occurs with the formation of a sparingly soluble compound of magnesium hydroxide:

MgCO ₃ + 2H ₂ O → Mg (OH) ₂ ↓ + H ₂ CO ₃

Magnesium hydroxide is the main component of scale at temperatures of 70-100 ° C, i.e. typical for evaporators operating at near atmospheric pressure. Magnesia scale differs from carbonate scale in higher density and thermal conductivity (by 10-15%). Magnesium hydroxide is much worse soluble in acids than carbonate scale.

Sulphate scale CaSO _{4 is the} most difficult to dissolve and constitutes the main obstacle in evaporators at temperatures above 100-120 ° C. Its precipitation is a direct consequence of a decrease in the solubility of calcium sulfate with increasing temperature of the solution.

The negative side of scale formation is due to the low thermal conductivity of scale deposits (0.2-1.2 W / (m · K)), which is ten times less than the thermal conductivity of metal (30-35 W / (m · K). Therefore, even a small thickness of scale deposits on heat-exchanging surfaces leads to a significant decrease in the performance of the op-amp, and when the scale thickness reaches more than 0.8-1.0 mm, it is already necessary to stop and remove the desalination plant itself to clean the heat-exchanging and working surfaces of the above-mentioned elements and assemblies of the op-amp from boil by widely known methods (for example, acid purification), which is a very lengthy and time-consuming process.

Therefore, the rate of scale formation processes, which determines the period between cleanings, can serve as an objective criterion for assessing the reliability of the OS.

In this regard, an urgent social need and an urgent task to ensure the required operational reliability of the desalination plant is to reduce the rate of scale formation on the working surfaces of its elements by searching for temperature conditions and using appropriate technological devices.

In the well-known OS, the task of ensuring an acceptable rate of scale formation on the heat transfer surfaces of an external multi-pass shell-and-tube steam heater of feed water and shell-and-tube condensers of secondary steam operating in the regenerative heat transfer mode (through a heat transfer wall) without evaporation is solved by using low-potential sources of heating steam (for example, steam from auxiliary turbines) to limit the temperature of heating sea water and the use of deep vacuum benching desalination plant operation, i.e. by reducing the heat stress of the heat exchange surfaces and the temperature of the working processes. However, to ensure the required reliability of the operation of the secondary steam separators of the louvre type and throttle-spraying devices (DRU), designed to bypass and spray the evaporated supersaturated brine in the conditions of increasing concentration of hardness salts in the solution during its subsequent stepwise evaporation, this is clearly insufficient, which determines the need for additional technological devices to reduce the rate of scale formation on the working surfaces of the louvre channels secondary separators of secondary steam, throttle openings and bypass channels of the switchgear, caused by the crystallization of hardness salts on natural crystallization centers (roughness, roughness, contamination) that are always present on these working surfaces, which can cause a violation of the operating mode of the op-amp and can even lead to the need to completely stop it, which is very important.

There is a known attempt to use “granular additives” in OS, which involves the use of finely dispersed powders (for example, chalk) by introducing them into the volume of feed water in an amount of 8-10 g / l as “seed crystals,” [V. Kovalenko, Lukin G.Ya. Ship water desalination plants. L .: Shipbuilding, 1970.- S. 110-111]. These particles, the total surface of which turns out to be much larger than the total surface of the natural crystallization centers on the rough wall, being the crystallization centers in the volume of the supersaturated solution, make it possible to divert the scale formation process from the rough surface of the stepped bypass channels and throttle openings of the differential switchgear onto particles suspended in the liquid volume, i.e. . replace the scale formation process on the working surfaces with intensive sludge formation in the volume of a supersaturated solution. In this case, due to the decrease in the supersaturation of the solution on these “seed crystals” in the brine volume contained in the bottom zone and brine receivers of the subsequent evaporation stage, favorable conditions are created for reducing scale formation on the surfaces of the working channels of the louvre separator by reducing the concentration of hardness salts in brine droplets introduced in them together with the stream of separated secondary steam. The noted set of processes proceeds similarly along the entire path of stepwise adiabatic evaporation and sequential bypass and throttle spraying of the brine.

However, the implementation of this technical solution associated with the use of “seed” materials with a specific gravity of 2.7-2.8 g / cm ³ (significantly higher than the density of water ρ = 1.0 g / cm ³ ) in the known multi-stage adiabatic desalination plant is with the need to organize effective circulation in the liquid volume to prevent deposition of “seed” materials on the bottom of the evaporator in the lower zone of the chambers of the evaporation stages, which necessitates the installation of special devices for efficient mixing the volume of liquid in the bottom zone of the evaporation stages, which is quite complicated and unreliable. In this case, the inevitable precipitation of “seed” materials, predetermining a decrease in the number of “seed” crystals in the volume of a supersaturated solution during its stepwise evaporation and sequential bypass and throttling, reduces the efficiency of anti-scale formation in the marked elements of the evaporator. Moreover, the need for pre-preparation and dosage of fine powders leads to a significant increase in the cost and complexity of servicing the well-known desalination plant. As a result, this technological method does not provide an effective solution to the technical problem posed to increase the reliability of the desalination plant and has not found its application

The task of the claimed group of inventions is to eliminate the noted drawbacks, namely: refusal to use additional ″ seed ″ materials; reducing the complexity of servicing the technological device; ensuring an effective reduction in the rate of scale formation on the surfaces of the working channels of the louvered separators of the secondary steam, as well as in the openings and bypass channels of the switchgear and increasing the reliability of the OS by developing and using fundamentally new technological and design solutions.

The technical task is achieved in that in a well-known desalination plant, including:

- an external multi-pass (over heated water) shell-and-tube steam feed water heater, having a straight-tube bundle with a dividing wall forming a vapor-air cavity for collecting and subsequent removal of the non-condensed vapor-air mixture, and also equipped with a condensate collector with its level sensor;

- two-stage steam-jet ejector;

- a condenser of a two-stage steam-jet ejector with separate condensation chambers of the air-vapor mixture, respectively, from the ejectors of the first and second stages, which together with the cooling water pipes are connected in series therein, condenser coolers with their condensate collectors connected between themselves by a U-shaped pipe, and also equipped with separate pipes air exhaust from these condensation chambers. Moreover, the volume of the lower zone of the condensation chambers is used here as a condensate collector;

- pumps (feed, condensate, brine), pipelines, disconnecting and switching automatic valves, control and measuring devices (thermometers, manometers, vacuum gauges, flow meters), automatic control and protection means (straw meters, condensate and distillate level controllers, temperature controllers, etc. .);

- a multi-stage adiabatic evaporator mounted in a sealed enclosure made in the form of a rectangular parallelepiped, and containing vertical separation walls that form separate evaporation stages, in each of which a two-pass (through cooling water) shell-and-tube secondary vapor condenser having a straight tube bundle is horizontally installed in each with a dividing wall forming a cavity for the collection and subsequent removal of not condensed vapor-air mixture, as well as equipment ny distillate collector, and in the middle zone of the vapor separator is mounted louvre type for separating droplets of brine entrained in the rising vapor and separating the secondary data at the top stage of evaporation zone, which is a capacitor and a bottom, which is the evaporator. At the same time, in the lower zone of each evaporation stage, a brine receiver of this evaporation stage is made, made in the form of an overflow pipe with an increased diameter, with bypass pipes of the subsequent throttle-spray device of the subsequent evaporation stage connected to it. Moreover, each of these bypass pipes contains in its upper free part a built-in throttle device, above the upper cut of each of which there is a mushroom-shaped chipper, which acts as reflectors of “fountain” jets of water flowing from the holes of the throttle device, which contributes to the droplet spraying of an overheated brine and creates conditions for its effective evaporation.

All data of the evaporation stage are sequentially communicated among themselves by connecting bypass pipes of the cooling water of the secondary steam condensers and are equipped with pipes of sequential bypass of the resulting vapor-air mixture from the respective cavities of these secondary vapor condensers in the direction from the first evaporation stage to the last, and two adjacent chambers of the evaporation stages are in series connected between in the lower zone bypass pipes from the brine receivers of a given evaporation stage to the throttle evacuation devices of the subsequent evaporation stage. In this case, the brine receiver of the last evaporation stage is in communication with a pumping brine pump, the pressure pipe of which has a branch jumper with a valve integrated in the pipe in front of the evaporator feed pump, the pressure cavity of which is connected to the receiving pipe of the cooling pipes of the secondary vapor condenser of the last vaporization stage. Moreover, the pressure pipe of the feed pump is equipped with a flow meter, and an overboard water filter is built into its suction pipe. The mentioned branch jumper with a valve is used to maintain the calculated temperature of the cooling water at the inlet to the condenser of the last evaporation stage when swimming in cold waters by partially transferring the brine into the cooling (feed) water pipeline.

The multistage adiabatic evaporator (hereinafter referred to as the "evaporator") also contains a system of interstage throttle washers mounted on the mentioned pipes of the sequential bypass of the vapor-air mixture from the secondary vapor condensers. In this case, the vapor-air cavity of the secondary vapor condenser of the last stage of evaporation is in communication with the receiving cavity of the mixing chamber of the first-stage steam jet ejector, the output diffuser part of which is connected with the vapor-air cavity of the condensation chamber of the condenser of the first stage of the steam-jet ejector. The cavity of the mixing chamber of the second stage steam-jet ejector is connected to the pipe for exhausting air from the condensation chamber of the condenser of the first stage of the steam-jet ejector, and the output diffuser of the steam-jet ejector of the second stage is connected to the vapor-air cavity of the condensing chamber of the condenser of the second stage of the steam-jet ejector equipped with a pipe for exhausting air into the atmosphere.

The marked scheme for the removal of the vapor-air mixture from the condensers of the secondary vapor of the evaporator using intermediate condensation of the mixed medium in the condensation chamber of the first-stage steam-jet ejector allows to significantly reduce the flow of working steam to the second-stage steam-jet ejector by reducing the volume of the transported medium entering the cavity of its mixing chamber.

The inlet nozzle part of both of these ejectors is connected in parallel to the working steam supply pipeline, and the condensate collector cavity of the condenser chamber of the condenser of the first stage of the steam-jet ejector is connected to the condensate collector cavity of the external multi-pass shell-and-tube steam feed water heater.

In this case, a stepwise increasing working vacuum in the evaporation stages of the evaporator is ensured by condensation of the secondary vapor in the condensers of the corresponding evaporation stages and the operation of a two-stage steam-jet ejector sucking the vapor-air mixture from the vapor-air cavity of the secondary vapor condenser of the last stage of the evaporator through the mentioned system of interstage throttle washers interstage bypass of the vapor-air mixture.

A discharge pipe of the cooling water of the condenser of the condenser of the first stage of the steam jet ejector is connected to the receiving part of the water cavity of the external multi-pass shell-and-tube steam heater whose vapor cavity is also connected to a low-grade source of heating steam and through a steam line with an integrated temperature controller. Moreover, this heater itself is made with a cross direction of movement of their mutually heat-exchanging media with a rectilinear direction of movement of the heated stream.

The output part of the water cavity of the external multi-pass shell-and-tube steam feed water heater, in turn, by means of a discharge pipe equipped with a temperature sensor connected to a temperature controller by a control pulse integrated in the supply steam of the heating steam, is in communication with the input pipe of the feed water receiver of the first evaporation stage evaporator integrated along the axis of its elliptical bottom, and bypass pipes are connected to the output part of this feed water receiver throttle switching first stage evaporator evaporation.

The distillate collectors of all secondary vapor condensers are pairwise connected in series with each other by interstage distillate bypass pipes, each of which is made in the form of a U-shaped pipe, the height of the liquid column in which uniquely determines the working pressure difference between the evaporator evaporation stages, i.e. the difference in saturation temperatures of the evaporated brine in adjacent evaporation stages. In this case, the distillate collector of the condenser of the secondary steam of the last evaporation stage is connected to the receiving pipe of the distillate tank, connected by a pipe with a pumping distillate pump.

The mentioned interstage movement of the distillate, as well as the vapor-air mixture and the evaporated brine is carried out due to the difference in working pressure in adjacent evaporation stages of the evaporator.

The air cavity of the distillate tank is in communication with the vapor-air cavity of the secondary steam condenser of the last stage of evaporation of the evaporator to equalize the pressure in these cavities and the reliable flow of the distillate. Moreover, the distillate tank is equipped with a level sensor communicated by a control pulse with a tank level regulator built into the pressure part of the pipeline of this pump to maintain its working level and stable operation of the pumping distillate pump. Moreover, a flow meter and an automatic three-way switching solenoid valve are installed on the outlet section of the pressure pipe of the pumping out distillate pump, which switches this pipe to discharge the distillate at its low quality by its connection via a control pulse with a solenometer installed on the measuring branch jumper of the distillate circuit.

The steam-air mixture from the vapor-air cavity of the external multi-way shell-and-tube steam feed water heater is diverted by means of a pipeline to the steam-air cavity of the secondary steam condenser of the first stage of evaporation of the evaporator, and the condensate from the heating steam from the condensate collector of this external multi-pass shell-and-tube steam heater of the feed water is discharged through the pipeline through the pipeline for its reuse in the vapor condensate cycle. At the same time, its condensate collector is equipped with a level sensor communicated by a control pulse with a level regulator installed on the pressure pipe of the condensate drain pump to maintain the operating level in the condensate collector and the stable operation of the pump. Moreover, an automatic three-way switching solenoid valve is installed at the output section of its pressure pipeline, which switches this pipeline to condensate discharge at its low quality by means of its connection via a control pulse with a straw meter installed on the measuring branch jumper of the condensate circuit; DIFFERENT from it, the claimed installation additionally contains a two-section receiver of feed water with nozzles for supplying and discharging aqueous media, installed in front of the receiver of feed water for the first stage of evaporation of the evaporator, and a thermal softener containing nozzles for supplying and discharging working media. In this case, the pipe for supplying an aqueous medium to it is in communication with a branch having a control valve, a flow meter and a level regulator. Moreover, this branch is built into the outlet pipe of the outlet part of the water cavity of the external multi-pass shell-and-tube steam feed water heater. The outlet pipe of the aqueous medium with the suspended slurry of the thermal softener is in communication with the inlet pipe of the two-section feed water receiver, and its pipe of the outlet of the vapor-air medium is in communication with the vapor-air cavity of the external multi-pass shell-and-tube steam feed water heater. The pipe for supplying steam to the softener is connected to a source of heating steam for additional heating of the aqueous medium in it.

The two-section feed water receiver itself contains a cylindrical body with an elliptical cover and bottom, nozzles for supplying and discharging aqueous media, nozzles for connecting a water indicating column in its upper part and is equipped with a level sensor (for example, a float type) installed in the upper part of its cylindrical body, and also has an additional shell inside the case, built along the axis of its elliptical bottom with a length along its height from the bottom equal to the height of the cylindrical part of the body, and forming two vertices open open cavities: external and central. The external cavity by the branch pipe located in its lower zone is in communication with the pipe for supplying the aqueous medium of the feedwater receiver of the first evaporation stage of the evaporator, and the central cavity with the supply pipe integrated along the bottom axis is connected to the discharge pipe of the outlet part of the water cavity of the external multi-pass shell-and-tube steam heater water containing a control valve and a level controller communicated by a control pulse with a level sensor of a two-section feed water receiver, anovlennym in the upper part of its cylindrical body. Moreover, its central cavity in the lower zone is also in communication with a water supply pipe with suspended sludge from a thermal softener for their high-quality mixing with feed water. On the axis of the elliptical cover, an air exhaust pipe is integrated, connected to the pipeline with an air valve.

As part of the inventive desalination plant, as a whole, these additional components are intended for the implementation of two technologically interconnected processes. So, the heat softener, as part of the whole, which can be used independently, is a technological device in it for generating particles of mobile sludge in the volume of a solution supersaturated with scale-forming salts, which are subsequently used as a whole, namely in a two-section receiver of feed water as ″ seed crystals ″ To reduce the supersaturation of hardness salts in the volume of heated feed water of the first stage of evaporation of the evaporator due to sludge formation in its volume (thermal softening).

At the same time, the heat softener, as a part of the whole, being the determining element in this interconnected technological chain of thermal softening of the OU feed water, meets the following fundamental requirements: the ability to generate the maximum number of mobile sludge particles in the volume of a supersaturated solution and to ensure efficient liquid removal with the highest content of these sludge particles.

It is known, adopted as a prototype, a device-thermal softener designed for heat treatment of make-up network water of heating boilers using source fresh water with increased mineralization [A.S. No. 1615459 of the USSR dated 12/23/1990 / Device for water treatment. IPC F22D 1/30, C02F 1/20, C02F 103: 02], comprising a vertical cylindrical body with a cover, a bottom and a steam supply pipe, as well as steam discharge pipes, softened water and sludge, and also containing a water supply manifold with distribution nozzles under which the contact-film-type water heaters of confuser type arranged in a horizontal partition are placed; two vertical cylindrical shells concentrically mounted on the bottom of the housing along its axis and forming three vertical open cavities (thermal softening sections), of which the outer cavity is formed by the inner surface of the housing and the peripheral shell, the middle is formed by the peripheral and central shells, and the central shell itself forms housing the central cavity. Moreover, in the known device in the lower part of the central shell along its perimeter, cutouts are made for the flow of fluid from the central cavity to the middle.

In this case, the known relative position of the heating steam pipe, the water supply and softened water collectors, as well as the sludge purge and vapor removal pipes, is made taking into account the countercurrent movement of the heated water and heating steam for the effective implementation of heating and degassing processes, as well as the organization of thermal softening processes solution in the direction from the central cavity to the external by successively alternating the lowering and lifting movements of the heated fluid in these softening cavities with stage-by-stage blowing of the formed sludge and supply of softened and degassed water from the external cavity to recharge heating networks. This arrangement of the processes of thermal softening of water to a certain extent meets the requirements of high-quality preparation of make-up network water.

However, the known structural and layout technical solution does not allow to realize, which is its drawback, the main idea of the invention for the generation of particles of mobile sludge for its subsequent use as “seed crystals” with the highest content of these sludge particles at the output of the device. This is due to the fact that in the prototype device, the removal of thermally softened water is carried out from the external cavity of the thermal softening section, where the concentration of sludge particles is minimal. At the same time, experience has shown that an attempt to increase their concentration by closing sludge blowdown nozzles from the device body and increasing the fluid velocity to values that exceed the sedimentation rate (sedimentation) of the sludge in its middle softening cavity is associated with the need for significant structural changes. Moreover, the organization of drainage of sludge-containing water from the external cavity, which has the largest cross-section (perimeter) compared to other cavities, is very difficult, which naturally requires additional structural refinement to prevent sedimentation and accumulation of sludge in its lower zone. Those. The known technical solution has drawbacks, namely: it does not provide the ability to efficiently drain water with the highest content of suspended sludge particles, for their subsequent use as “seed crystals”, which is the main task of a single inventive concept.

To eliminate the noted drawbacks of the known thermal softener containing a vertical cylindrical body with a bottom, a cover and a steam supply pipe, as well as steam discharge pipes, softened water and sludge, as well as a water supply manifold with distribution nozzles, under which the receiving contactors are arranged in a horizontal partition -confuser-type film water heaters; as well as containing two vertical cylindrical shells mounted concentrically on the bottom of the housing along its axis and forming three vertical open cavities (thermal softening sections), of which the outer cavity is formed by the inner surface of the housing and the peripheral shell, the middle is formed by the peripheral shell and the central shell, and the central shell forms a central cavity in the body, UNLIKE it the claimed thermal softener additionally contains a perforation built into the body under its cover an oriented diaphragm having openings in its peripheral zone for organizing uniform steam supply to the water heating zone; a domed horizontal partition installed with an annular gap relative to the inner wall of the housing on the supporting elements on these walls and located below the horizontal partition with the receiving contact-film contact-film water heaters of confuser type arranged in it, and further comprises a vapor removal manifold installed under this dome-shaped partition. The upper end of the peripheral shell is located above the upper end of the Central shell, and the length of both of them in height from the bottom is more than half the height of the casing of the softener. In the lower part of the peripheral shell along its perimeter, cutouts are made for the flow of fluid from the external cavity to the middle. The shape of the bottom of the body and its cover is elliptical. The water outlet pipe is combined with the discharge of sludge particles and mounted along the axis of the elliptical bottom of the body under its central cavity, and the steam supply pipe is mounted in the elliptical cover of the body along its axis.

The cylindrical body, in its upper part, is equipped with nozzles for connecting a water indicating column, and is also equipped with a level sensor (for example, a float type). Moreover, the level sensor is connected by a control pulse to a level controller installed on the branch pipe of the outlet part of the water cavity of the external multi-pass shell-and-tube steam feed water heater, which is connected to the pipe for supplying the aqueous medium of the thermal softener, and the collectors for the removal of vapor and the supply of water to the contact-film water heaters , vertical cylindrical shells and a domed horizontal partition made of heat-resistant hydrophobic food layers mass

The claimed performance of the named structural elements located in the most corrosive and scale-hazardous zone of the heat softener from heat-resistant hydrophobic food plastics is aimed at increasing the reliability and durability of the operation of this device, while it is essential that the manufacture of unloaded heat softener elements using plastics with less compared with metal specific gravity provides a reduction in the mass and cost of the device.

In turn, the manufacture of a horizontal domed septum, peripheral and central shells made of plastic with hydrophobic properties that worsen the conditions of scale deposition on the outer surface of the domed horizontal surface and the vertical surfaces of the cylindrical shells, prevents the solution from being supersaturated due to scale formation before it enters the outer section, as well as in the softening sections themselves in the direction of movement of the supersaturated solution, which is an additional factor Contributing to the increase in their efficiency of generation of sludge particles, which are the main target termoumyagchitelya technological production, which is very important and crucial to achieve the targets for the efficient generation of sludge particles.

In addition, in accordance with the requirements of the sanitary and epidemiological rules and standards of SanPiN 2.1.4.1074-01, in devices related to the production of fresh water that can be used as drinking water, the use of food plastics is excluded, which exclude the release of harmful substances during heating, and are certified in in accordance with the requirements of the guidelines MU 2.1.4.78-99 "Hygienic evaluation of materials, reagents, equipment, technologies used in water supply systems."

The inventive design and layout solutions for the thermal softener, in the aggregate of its features, are aimed at implementing the basic requirements for this technological device, namely: organizing efficient generation of movable slurry particles in the volume of a supersaturated solution and ensuring water drainage with the highest content of suspended slurry particles, for their subsequent use as ″ seed crystals ″.

At the same time, the key technical requirements for the thermal softener are implemented, based on the known laws of thermal softening of highly mineralized waters, which boil down to the following:

- the efficiency of the process of generating particles of mobile sludge in the volume of a supersaturated solution, based on the use of negative solubility of hardness salts, increases with increasing temperature of the heating fluid and, consequently, an increase in the supersaturation of the solution, while the presence of crystallization centers (vapor bubbles, sludge particles) serves as a catalytic factor in the volume of fluid;

- the intensity of reducing the supersaturation of the solution (kinetics of thermal softening) due to sludge formation in its volume, and the degree of completion of the process of thermal softening depends on the hydrodynamic regime of fluid movement (laminar, laminar-turbulent or turbulent) and the residence time of the solution in the zone of thermal softening . So, in the turbulent mode of motion, due to the active removal of fluid from the zone with less supersaturation of the solution into the zone with increased supersaturation, there is a general decrease in the supersaturation of the softened solution in the direction of its movement, which ultimately determines a decrease in the intensity of sludge formation. Therefore, the greatest efficiency of sludge formation can be achieved only with the laminarization of fluid motion, which weaken such mixing throughout the volume and the resulting reduction in the supersaturation of the softened solution. In this case, the greatest concentration potential is achieved for effective sludge formation during thermal softening of the solution.

All these positive factors providing optimal conditions for the efficient generation of moving sludge particles are implemented in a thermal softener by using additional contact heating of softened water with heating steam, by using a section of the water volume of the thermal softener, which excludes mixing of the liquid in its entire volume. Moreover, the level of laminarization of a moving fluid in the thermal softening sections themselves is determined by the speed of the flow, i.e., the cross-sectional area of these sections.

In the inventive thermal softener, as part of the whole, the technological process for the generation of mobile particles of sludge in the volume of a supersaturated solution is as follows.

Feed water through a branch containing a control valve, a flow meter, a level regulator and built into the heated feed water discharge pipe from the outlet water cavity of an external multi-pass shell-and-tube steam feed water heater is supplied to the water supply manifold and then through its dispensing nozzles to the contact-film water heaters of the confuser type, embedded in a horizontal partition, where it flows in film mode on their internal confuser surface. Heating steam through a pipe placed along the axis of the elliptical cover is fed into the heating zone through a perforated diaphragm having holes in its peripheral zone and placed horizontally under the elliptical cover, uniformly flows to contact-film water heaters of confuser type, where, due to condensation of the heating steam on the free surface of the gravitationally flowing liquid film, its effective additional heating is provided. Such contact heating using a confuser made of low-heat-conducting material ensures a minimum temperature in the near-wall layers of the liquid, which is essential for creating conditions for a non-scale operation of the contact water heater itself. Further contact heating is carried out in the mode of an annular jet-film fluid flow at the outlet of the water heater in a satellite-transverse mode of movement of heating steam. In this case, the heated water enters the outer surface of the horizontal domed partition placed below the horizontal partition with the contact-film water heaters of confuser type arranged in it and flows in the form of jets into the outer section of thermal softening formed by the inner surface of the casing and the peripheral shell. In this area, water heating is ensured by condensation of the heating steam on the external surfaces of the water jets streamlined by it. Throughout the path of its transversal motion, the heating steam provides “ventilation” of the free surfaces of the heated fluid, helping to remove the released gases through the vapor removal manifold located under the domed partition. Due to the location of the vapor-air mixture exhaust manifold under a domed partition having a maximum area in the lower cross section, and taking into account that the flow rate of the vapor removed with a change in the direction vector by 90 ° does not exceed 3-5% of the flow rate of the heating steam, the removal of salt-containing droplets is excluded moisture together with the vapor, which allows you to send the vapor to the appropriate condenser (external multi-pass shell-and-tube steam feed water heater) for the subsequent return of condensate in the vapor natal cycle.

The inventive scheme for organizing additional heating of the liquid in the mode of transverse-lateral movement of heating steam in combination with active ventilation ’of the free surfaces of the heated water determines an increase in the partial pressure of the vapor at the interface, thereby minimizing the liquid’s under-heating to the saturation temperature corresponding to the pressure in the case of the softener , which helps to achieve maximum supersaturation of the solution with scale-forming salts at the inlet of the external softening section, which I is a factor that intensifies the generation of primary sludge particles in this section of thermal softening.

In this case, vapor particles trapped by jets of liquid flowing down from the domed septum create a zone saturated with steam bubbles in the upper zone of the external section of thermal softening, which moves downward along with the liquid. Moreover, steam bubbles of various sizes perform various functions in the process of movement of the solution in the outer section of thermal softening. So large vapor bubbles contribute to the degassing of the heated liquid due to the diffusion of the released gases into their volume, and as they grow, these steam bubbles float up to the ventilated phase boundary, helping to remove gases together with the vapor. At the same time, the smallest vapor bubbles, acting as crystallization centers, are a catalytic factor in the formation of nuclei of primary particles of sludge in the volume of a supersaturated solution in the outer softening section, which is very significant.

Along with the noted processes in the volume of the heated supersaturated solution in the external section of thermal softening, there is also a natural formation of crystallization centers (nuclei of the primary sludge particles), which occurs due to a decrease in the supersaturation of the liquid in the zone characterized by the highest concentration potential of the supersaturated solution.

In the solution volume of the subsequent sections of thermal softening: the middle formed by the central shell and the peripheral shell, which has cutouts in its lower part along its perimeter for the flow of fluid from the outer section to the middle, and the central section formed by the central shell itself, the primary crystallization centers grow ( sludge formation) generated in the solution volume of the external section of thermal softening. Moreover, due to the manufacture of a horizontal domed septum, peripheral and central shells made of plastics with hydrophobic properties, the scale deposits on the outer surface of the horizontal domed surface and the vertical surfaces of the cylindrical shells are deteriorating, preventing the solution from being supersaturated due to scale formation on these surfaces before it enters the outer section , as well as in the softening sections themselves in the direction of movement of the supersaturated solution and that is an additional factor contributing to an increase in the efficiency of generation of sludge particles.

In addition, due to the laminarization of the moving fluid, the greatest concentration potential is provided for the efficient generation and growth of sludge particles along the course of the softening solution, which are the main target technological products of the thermal softener.

The functional purpose of these sections of thermal softening is different, therefore, to organize the effective generation of sludge particles, a rational distribution of the total water volume of the thermal softener between the thermal softening sections is performed, namely:

- in the outer section, under conditions of maximum supersaturation of the solution due to its additional heating, and the presence of the smallest vapor bubbles, which serve as crystallization centers, the primary nuclei begin to intensively form crystallization centers and their growth begins (sludge formation). Moreover, the overall efficiency of the heat softener is largely determined by the efficiency of the organization of processes in this section, which is achieved by increasing the residence time and lowering the speed of the lowering movement of the solution. Therefore, the water volume of the outer section is set to the largest (at least half of the total water volume of the thermal softener);

- in the middle section in the lifting mode, further growth and enlargement of the sludge particles coming from the outer section occurs, as a result of which their total surface increases. In this case, the use of a single aqueous medium, which determines the identity of the chemical composition of the primary nuclei of the crystallization centers generated in the volume of the outer section, to the chemical composition of the softened solution, leads to less crystallization on these “seed” slurry particles in the volume of the supersaturated solution. Thanks to the noted catalyzing factor, the effective growth of slurry particles in the volume of the solution of this and the subsequent sections of thermal softening is ensured.

In the volume of the middle section for the effective growth of sludge particles in the volume of the supersaturated solution, laminarization of the fluid flow in the mode of its lifting movement is also required, which is achieved by ensuring the corresponding speed of movement and the residence time of the softened solution in it. As a result, the volume of the middle section occupies at least a third of the total water volume of the thermal softener;

- in the central section, in the mode of downward movement of liquid, the growth of slurry particles continues and ends at a stage sufficient for their further use as “seed crystals” in a two-section receiver for desalination feed water. At the same time, the growth rate of slurry particles in the volume of this section, occurring in the zone with the smallest supersaturation of the solution, will be lower than in the middle section, therefore, the main additional purpose of the central section is to provide water with the highest content of suspended slurry particles from its lower entrance zone two-section feedwater receiver.

In this case, the main criterion for evaluating the effectiveness of the thermal softener is the number and size of sludge particles at the output of the device.

There is a possibility of reducing the degree of supersaturation of the solution at the outlet of the heat softener (due to further growth of sludge particles) by increasing the number of softening sections. However, it must be borne in mind that in additional sections of softening, the processes of growth of sludge particles will proceed in the zone with lower supersaturation of scale-forming salts, which also determines the low growth rate of sludge particles. Therefore, the additional effect achieved by trying to increase the number of softening sections, coupled with a significant complication of the design and the deterioration of the weight and size characteristics of the softener, will be insignificant.

In this regard, it is significant that, in the claimed three-sectional design of the thermal softener, the size of the slurry particles at the output of the device, required for their subsequent effective use as “seed crystals”, is provided by changing the height of the water volume of the device (increasing the generation time of sludge particles) without changing its transverse dimensions which is extremely important.

To ensure the stable operation of the thermal softener, it maintains a constant optimal working fluid level. In this case, the limit range of the fluid level control zone is limited by the maximum upper and lower permissible fluid levels, which are determined respectively by the height of the upper edge of the intermediate shell and the overflow edge of the central shell. For these purposes, the softener is equipped with a level sensor (for example, a float type) installed in the upper part of the cylindrical body and communicated with a control pulse with a level regulator integrated in the branch connected to the outlet pipe of the heated feed water from the outlet part of the water cavity of the external multi-pass shell-and-tube steam heater of the feed water, as well as limit level sensors communicated by control pulses with the equipment of the light and sound signal op admonitions. The softener is also equipped with a water indicating column for visual level control.

Thus, the claimed part of the whole (DU), as a technical solution, in the aggregate of its distinctive features, namely: the inclusion in the composition of the well-known thermal softener of additional structural elements: a horizontal perforated diaphragm, a horizontal domed partition with a vapor collector installed underneath; application of water volume sectioning and organization of thermal softening processes in the direction from the external softening section to the central one in the sequential alternation of the lowering and lifting laminarized fluid movement in the softening sections; organization of water discharge with the highest content of generated particles of mobile sludge from the lower zone of the central section of thermal softening; the use of additional effective contact heating of the softened solution in the mode of satellite-transverse movement of the heating steam, which ensures maximum supersaturation of the solution with hardness salts at the inlet of the external section of thermal softening, which increases the generation efficiency of primary slurry particles in the volume of this section under the conditions of the smallest vapor bubbles performing catalytic function as crystallization centers in the formation of primary sludge particles; the manufacture of a horizontal domed septum, peripheral and central shells made of plastics with hydrophobic properties that worsen the scale deposition conditions on the outer surface of these elements of the thermal softener and prevent the solution from being supersaturated due to scale formation on these surfaces before it enters the external thermal softening section, as well as in softening sections in the direction of movement of the supersaturated solution and which is an additional factor contributing to the increase generation efficiency of the slurry particles; as well as the use of a single aqueous medium, which predetermines the identity of the chemical composition of the primary nuclei of the crystallization centers generated in the volume of the outer section, the chemical composition of the softened solution, which causes less crystallization on these “seed” slurry particles in the volume of the supersaturated solution, as well as the rational distribution of the water volume between sections of thermal softening, allow to sufficiently implement the technological tasks assigned to the thermo-softener in terms of efficiency hydrochloric generation and removal of slurry particles for further use as a "seed crystal" to reduce supersaturation in the bulk solution twopart feedwater receiver.

In the inventive two-section receiver of feed water, in the composition of the claimed op-amp, the process of thermal softening, due to its distinguishing features, occurs as follows.

Heated feed water is supplied to the inlet of the aqueous medium, located along the axis of the bottom of the central section of this two-section feed water receiver, through a pipe connected to the outlet of the water cavity of the external multi-pass shell-and-tube steam heater. Water with suspended sludge from the thermal softener, through a pipe located in the lower part of the housing, is also fed into the cavity of the central section of this two-section receiver. Such a scheme for supplying two aqueous media ensures their high-quality mixing, i.e. averaging the concentration of “seed” sludge particles in the liquid volume in its central cavity in the mode of its lifting movement, which is an indispensable condition for the effective implementation of thermal softening processes in the outer section of the two-section feedwater receiver in the mode of lowering the movement of liquid entering the cavity of this section by overflow through the upper edge of the additional shell of the Central section. In this case, the main factors determining the effectiveness of the process of thermal softening (sludge formation) in the water volume of the outer section are similar to the intensifying factors noted when considering the operation of the thermal softener.

In particular, due to the separation of the central section for mixing aqueous media, mixing in the volume of softened solution in the external section is eliminated, which allows it to realize effective thermal softening of feed water using “seed” sludge particles in a laminarized flow in the mode of downward movement. In this case, the use of an aqueous medium selected from the feed water supply line for generating slurry particles in the heat softener determines the identity of the chemical composition of these slurry particles to the chemical composition of the softened solution, which causes less crystallization on the said “seed” slurry particles in the volume of the supersaturated solution in the external section, serves as an additional factor stimulating the effective reduction of its supersaturation due to the increase in the size of primary sludge particles in the volume of solution RA in the course of its laminarized lowering movement. The achieved depth of thermal softening (concentration of hardness salts at the outlet of the device) is determined by the residence time of the solution in the external softening section, i.e. its volume. Therefore, to maximize the effective use of the volume of the external section of thermal softening, an additional shell is made with a length of its height from the bottom equal to the height of the cylindrical part of the housing, while the air is exhausted when the device is filled through a nozzle located along the axis of the elliptical cover of the housing of the two-section feed water receiver and connected to the pipeline with the air valve. At the same time, in order to maintain an optimal working level, it is equipped with a level sensor (for example, of a float type) communicated by a control pulse with a level regulator built into the supply pipe of heated feed water.

Softened feed water with suspended sludge is discharged from the lower zone of the cavity of the outer section of the housing through a nozzle built into the elliptical bottom and is fed to the input of the feedwater receiver of the first stage of evaporation of the evaporator, and its volume is used as an additional softening section of the two-section feedwater receiver, which allows to achieve a greater depth of softening of feed water, and which is extremely important for the implementation of a single inventive concept to reduce the rate of scale formation Nia in the elements of a desalination plant.

The need for additional inclusion in the composition of the claimed OS two-section receiver of feed water in the proposed design and layout is due to the following reasons.

The feed water receiver of the first evaporation stage of the known OA evaporator, containing a cylindrical body with a lid and an elliptical bottom and equipped with water supply and outlet pipes, does not sufficiently meet the requirements for effective softening of the feed water on the “seed” sludge particles generated in the thermal softener in due to the limited nature of its water volume, and consequently, the duration of the process of thermal softening. At the same time, the single-sectional design of the feedwater receiver does not provide simultaneous high-quality solutions to two related problems: efficient mixing of “seed” sludge particles in the volume of a supersaturated solution and the implementation of effective softening of a supersaturated solution. Those. in a single-sectional design, the feedwater receiver of the first stage of evaporation of the known solution, performing mainly the function of a mixer of “seed” slurry particles in the volume of a supersaturated solution, does not allow to sufficiently realize the main goal of the inventive concept of the claimed group of inventions to reduce the supersaturation of feedwater at the inlet evaporator.

Thus, the claimed two-section receiver of feed water in the aggregate of its distinguishing features, namely: sectioning of the increased water volume, by installing an additional shell with a length along its height from the bottom equal to the height of the cylindrical part of the housing, which allows to optimally solve the two-part technological task of efficient mixing of flows water with suspended sludge from the thermal softener and softened feed water (in the central section) and the organization of the subsequent effective heat nical softening of the mixed aqueous medium (the external section) in the downflow mode motion laminarizovannogo softening feedwater; and in conjunction with the use of the volume of the available feedwater receiver of the first stage of evaporation of the evaporator as an additional softening section, it achieves the target to effectively reduce the supersaturation of feed water at the inlet of the first stage of evaporation of the evaporator assigned to this significant additional element of the inventive desalination plant.

At the same time, the restrictive and distinctive features of the claimed OA together provide the following results.

Outboard (feed) water is supplied by the circulation feed pump through its filter and flow meter to the receiving water cavity of the cooling pipes of the shell and tube condenser of the secondary steam of the last stage of evaporation of a multistage adiabatic evaporator (hereinafter referred to as the "evaporator"). Further, passing sequentially in the cooling pipes of the condensers of the secondary vaporizer of the evaporator in the direction from the last stage of evaporation to the first, seawater increases its temperature due to the heat of condensation of the secondary water vapor. Such a scheme of movement of cooling water allows sufficiently fully regenerate the heat of condensation of the secondary vapor in the evaporation stages.

From the secondary steam condenser of the first stage of the evaporator, the cooling water through the cooling pipes of the condenser of the two-stage steam-jet ejector made with separate condensation chambers of the steam-jet ejectors of the first and second stages, where it is heated due to the heat of condensation of the mixed medium (working steam and air-vapor mixture from the secondary steam condensers) steam jet ejectors, brought to the inlet of the water cavity of the external multi-pass shell-and-tube steam heater, where the cooling the supply (feed water) is heated in the heating mode without evaporating the liquid due to the heat of condensation of the heating steam supplied to its vapor cavity from a low-potential source of steam (for example, extraction steam from auxiliary turbines).

In this case, the rate of scale formation in the mentioned OS elements along the movement of heated feed water, uniquely determined by the heat stress and temperature of the heat transfer pipes, is greatest in the external multi-pass shell-and-tube steam heater, which ultimately determines the need to limit the heating temperature of feed water to the level necessary to ensure in it the scale formation rate permissible under operating conditions, due to the use of a low-potential source of heating a couple. Moreover, to prevent excessive heating of the feed water in the pipeline, connected to the outlet of the water cavity of this external multi-pass shell-and-tube steam heater, a temperature sensor is installed that controls the operation of the temperature controller integrated into the supply steam line of a low-potential source of heating steam and maintaining the set heating temperature by changing the heating flow rate couple.

From the output part of the water cavity of the external multi-way shell-and-tube steam heater, heated seawater is supplied to the lower zone of the central cavity of the two-section feed water receiver, and part of this water is connected through the branch with a control valve, flow meter, and level regulator to the collector for supplying the water medium of the thermal softener.

An additional heating of the seawater taken from the feed water supply line is carried out in the heat softener due to the supply of heating steam, which contributes to an increase in its supersaturation with scale-forming salts and creates conditions for the efficient generation of mobile slurry particles in the volume of the supersaturated solution, which are subsequently used as seed crystals ″ To reduce the supersaturation in the volume of heated sea water in a two-section receiver of feed water due to sludge formation (thermal softening) on these ″ Seed crystals ″. The vapor from the heat softener is diverted to the vapor-air cavity of the external multi-pass shell-and-tube steam feed water heater.

In order to maintain a constant working level in the thermal softener, it is equipped in the upper part of the cylindrical body with a level sensor (for example, a float type), connected by a control pulse to a level regulator built into the mentioned branch, which also contains, as described, a control valve and a flow meter and reported as set forth, with a pipeline for discharging heated feed water from the outlet of the water cavity of the external multi-pass shell-and-tube steam feed water heater.

From the heat softener, water with suspended sludge through the outlet pipe of the aqueous medium, built-in along the axis of its elliptical bottom, and the pipe connected with it are connected to the central cavity of the two-section feed water receiver, where averaging of the concentration of slurry particles in the volume of feed water is achieved by mixing with the main stream, which is a prerequisite for ensuring an effective reduction in the concentration of hardness salts (softening) in feed water due to volumetric sludge formation in the external cavity two-section receiver of feed water in the mode of lowering the movement of liquid.

The softened water with suspended sludge was discharged from the body of the two-section feed water receiver through a pipe built into the elliptical bottom and communicated with its external cavity, and then, through a pipe connected to this pipe, softened water was supplied to the feed water receiver of the first stage of evaporation of the evaporator, volume which is used as an additional section of thermal softening. Moreover, the two-section receiver of feed water in the upper part of the cylindrical body is equipped with a water indicating column for visual control of the working level. To maintain a constant working level in this two-section receiver, it is also equipped with a level sensor (for example, a float type) installed in the upper part of its cylindrical body and communicated by a control pulse with a level regulator built into the feed water supply pipe. At the same time, air is exhausted during its filling through a nozzle integrated along the axis of the elliptical cover and in communication with the pipeline containing the air valve.

From the feed water receiver of the first stage of evaporation of the evaporator, through the bypass pipes of the throttle-spray devices (DRU) connected to it, softened feed water with suspended sludge enters the vacuum chamber of the first stage of evaporation of the evaporator.

Due to the inclusion in the composition of the claimed desalination plant, as a whole, of its technologically interconnected additional components: a thermal softener, which ensures the efficient generation of mobile sludge particles and their subsequent use in a two-section receiver of feed water as “seed crystals” to reduce feed water supersaturation in salts stiffness, and also due to the use of the volume of the feedwater receiver of the first stage of evaporation of the evaporator as an additional thermal softening section, a decrease in the concentration of scale-forming salts in the feed water containing sludge suspended in it at the inlet of the evaporator is achieved, which is essential for the implementation of the general inventive concept to reduce the rate of scale formation in the elements of the desalination plant.

In particular, bypassing, throttling spraying and evaporating such softened feed water in the first stage of evaporation of the evaporator, favorable conditions are created for reducing the rate of scale formation in the bypass channels and working surfaces of the throttle-spray devices (DRU) by reducing the concentration of scale-forming salts in the feed water at the inlet in the first stage of evaporation, as well as on the surfaces of the working channels of the louvered separator of the secondary steam by reducing the salt content of moisture droplets, we introduce h her secondary evaporation stage of the steam. Moreover, in the volume of unevaporated brine contained in the bottom zone of the evaporation chamber of the first stage of the evaporator and the brine collector of the second stage of evaporation, the processes of thermal softening of the brine occur due to the growth of sludge particles present in the brine volume.

Bypassing such a softened brine, for spraying and subsequent evaporation in the second stage of evaporation of the evaporator, the scale formation rate on the working surfaces of the bypass pipes and the openings of the differential switchgear decreases due to a decrease in the concentration of hardness salts in the brine, and also due to the replacement of surface scale formation by volume sludge formation with “seed” sludge particles contained in the brine volume. Moreover, the prevailing nature of volumetric sludge formation over surface scale formation here is due to the absence of overheating of the wall layers of the liquid (lack of heat supply), as well as the large total surface of the slurry particles, significantly exceeding the total surface of the natural crystallization centers on the working surfaces of the mentioned evaporation stage elements. Similarly, processes occur in subsequent stages of evaporation of the evaporator with sequential bypass, throttle atomization and evaporation. Coarse sludge particles are removed together with brine from the brine receiver of the last stage of evaporation of the evaporator by a pumping brine pump overboard.

A distinctive feature and the effect achieved in this case in the claimed group of inventions, both as a whole and its additional parts, is the use of a single thermophysical process ″ heating ″, which is fundamental in the thermal distillation desalination of sea water, as well as in the use of a single aqueous medium for generation ″ Seed ″ sludge particles used in the future for thermal softening of feed water at the inlet to the evaporator and brine in its evaporation stages, which, predetermining the ident The chemical composition of these sludge particles because of the chemical composition of the softened solution results in less crystallization work on these “seed” sludge particles in the volume of the supersaturated solution, i.e. is a catalytic factor for effective sludge formation (increase in the size of sludge particles) in the volume of the solution with a corresponding decrease in its supersaturation with hardness salts in the course of its movement in the OS elements.

In this case, the partial recirculation mode of the purged brine through a branch jumper with a valve built into the suction pipe of the feed pump used in the well-known OS for maintaining the calculated temperature of the cooling water at the inlet to the evaporator when the ship is sailing in cold waters can be recommended here as a constant mode of partial recirculation of the purged brine containing particles of suspended sludge to reduce the rate of scale formation on the internal heat transfer pipe surfaces, along the entire path of the sequential passage of heated sea water in the cooling pipes of the secondary steam condensers, the two-stage steam jet ejector condenser and the multi-pass shell-and-tube steam feed water heater, due to the distraction of the crystallization of hardness salts from their working surfaces onto the particles of the moving sludge introduced by the recirculating brine into volume of transported sea water, i.e. by replacing surface scale formation with bulk sludge formation, which is an additional very significant effect.

At the same time, the restrictive condition for using such constant partial recirculation is the permissible excess of the calculated temperature of the cooling water at the inlet of the secondary steam condenser of the last evaporation stage, which ensures an acceptable decrease in the operational performance of the claimed desalination plant.

Thus, the proposed technical solutions for the structural layout of the heat softener and the two-section feed water receiver and circuit solutions for their inclusion in the desalination plant allow us to sufficiently implement the technical task of the inventive concept to increase the reliability of the multi-stage adiabatic desalination plant, namely: reducing the scale formation rate by working surfaces of interstage bypass pipes and throttle-spray devices, as well as on on the channel surfaces of the louvers of secondary steam separators, which is achieved by efficiently generating primary “seed” sludge particles suspended in an aqueous medium in a thermal softener and then using them as crystallization centers to reduce the saturation of feed water in the volumes of a two-section feed water receiver and feed water receiver of the first evaporation stage as well as brine contained in the bottom zone of the evaporation chambers, cavities of the brine receivers and the bypass pipes connected to them ossel-spraying devices during the sequential passage of the evaporated solution in the evaporation stages.

In addition, it is possible to reduce the rate of scale formation on the heat transfer surfaces of secondary steam condensers, a two-stage steam jet ejector condenser, and an external multi-pass steam feed water heater during op-amp operation in the mode of partial recirculation of brine containing suspended sludge particles due to distraction of crystallization of scale-forming salts from heat transfer salts surfaces on these particles of sludge, i.e. replacing surface scale formation with bulk sludge formation along the entire path of sequential heating of feed water.

Moreover, due to the use of a single thermophysical process (heating) and a single aqueous medium during the implementation of distillation desalination of sea water and the generation of mobile sludge, the need to use additional technological materials is eliminated and technical conditions are created for the complete automation of the claimed desalination plant by using uniform automation tools.

It is also important that the sludge that is removed together with the brine in its composition (CaCO ₃ , Mg (OH) ₂ , CaSO ₄ ) is inert and environmentally friendly, i.e. the technological processes used to solve the technical problem are environmentally friendly, which is extremely important in conditions of tightening the requirements for environmental safety of the technologies used.

The claimed group of inventions - desalination plant and its thermal softener - is illustrated by the following illustrations.

Figure 1 presents the thermal diagram of a five-stage adiabatic deep-vacuum desalination plant.

Figure 2 - schematic diagram of the connection of a two-stage steam-jet ejector to its capacitor.

Figure 3 - structural layout of the external multi-pass shell-and-tube steam feed water heater.

Figure 4 - structural layout of the thermal softener.

In Fig.5 - site placement confuser-film contact water heater.

Figure 6 is a structural diagram of a two-section receiver of feed water.

7 is a graph of the physical processes occurring in the thermal softener.

On Fig is a graph of physical processes at the input of a five-stage adiabatic evaporator.

Figure 9 is a graph of physical processes occurring in a five-stage adiabatic evaporator.

The essence of the claimed group of inventions, both as a whole and part thereof, is illustrated by the example of their specific technical design and use as part of a five-stage adiabatic desalination plant with a capacity of 240 tons / day, similar to the well-known adiabatic deep-vacuum desalination plant of type M5.

This five-stage adiabatic desalination plant, the thermal circuit of which is presented in figure 1, contains the following elements:

- circulation feed pump 1, its filter 2 and flow meter 3;

- five-stage adiabatic evaporator 4 mounted in a sealed enclosure made in the form of a rectangular parallelepiped, and containing vertical separation walls forming five stages of evaporation. In the upper part of the evaporator evaporation stages, two-way shell-and-tube secondary-steam condensers 5, 6, 7, 8, 9 are horizontally installed, each of which contains a straight-tube bundle of cooling pipes with a dividing wall (not shown) forming a cavity for collection and subsequent removal of non-condensing vapor-air mixture (not shown), as well as those equipped with a distillate collector 10.

In the middle zone of the evaporation stages of the evaporator, louvre type 11 secondary steam separators are mounted, separating the evaporation stages of the evaporator into two zones: the upper one is the condenser and the lower one is the evaporation one, while the brine receiver 12 of this evaporation stage is placed in the lower zone of each evaporation stage, made in the form of a lowering pipes of increased diameter, with overflow pipes 13 connected to it of the subsequent evaporation stage. These bypass pipes contain in their upper free part built-in throttle devices (not shown), above the upper cut of each of which there are mushroom-shaped chippers 14, which act as reflectors of “fountain” jets of water flowing from the holes of the throttle device, which ensures subsequent drip spraying of the overheated brine and creates the conditions for its efficient evaporation.

All the evaporation stages of the five-stage adiabatic evaporator 4 (hereinafter referred to as the “evaporator”) are sequentially interconnected by connecting bypass pipes of the cooling water of the secondary vapor condensers and equipped with consecutive interstage bypass pipes of the resulting air-vapor mixture from the respective cavities of these condensers in the direction from the first evaporation stage to the last, throttle washers 15 are integrated in these interstage bypass pipes, and distillate collectors 10 of all condensate the secondary steam tori are pairwise sequentially interconnected by interstage bypass pipes of the distillate 16 in the direction from the secondary steam condenser of the first stage 9 of the evaporation of the evaporator to the fifth 5, made in the form of a U-shaped pipe. In the lower zone of the evaporation stages of the evaporator 4, two adjacent chambers of the evaporation stages are pairwise sequentially interconnected by bypass pipes 13 from the brine receivers 12 of this evaporation stage to the throttle-spray devices (ДРУ) of the subsequent evaporation stage. In this case, the interstage movement of the vapor-air mixture, distillate and evaporated brine is carried out due to the difference in working pressure in adjacent evaporation stages of the evaporator 4.

The adiabatic multi-stage desalination plant (DU) also contains:

- a condenser 17 of a two-stage steam jet ejector with separate chambers for condensation of the steam-air mixture from steam jet ejectors of the first 18 and second 19 stages, the condenser 17 (FIG. 2) of the two-stage steam-jet ejector consisting of these separate chambers 20 and 21 of condensation of the steam-air mixture respectively from steam jet ejectors of the first 18 and the second 19 steps, forming together with series-connected pipes of cooling water 22 refrigerators-condensers in them with their condensate collectors, and as a failure here, the bottom of the condensate is used the lower part of the cavity of these condensation chambers, connected between themselves by a U-shaped pipe 23. The chambers 20 and 21 are also equipped with separate branch pipes for the removal of vapor 24 and air 25 from these condensation chambers, respectively.

In this case, the air-vapor mixture from the corresponding cavity of the secondary steam condenser 5 of the fifth stage of evaporation of the evaporator 4 (Fig. 1) is diverted to the receiving cavity of the mixing chamber of the steam jet ejector of the first stage 18, the output diffuser part of which is in communication with the steam-air cavity of the condensation chamber 20 of the condenser of the steam condenser ejector of the first stage. The mixing chamber of the steam jet ejector of the second stage 19 is connected to the pipe 24 for discharging the non-condensing vapor-air mixture (vapor) from the condensation chamber 20 of the steam jet ejector of the first stage 18, and the output diffuser of the ejector of the second stage 19 is connected to the vapor-air cavity of the condensation chamber 21 of the condenser chamber 21 of the condenser of the steam jet ejector 19 of the second , from which air is discharged into the atmosphere through the pipe 25. The inlet nozzle of these ejectors is connected in parallel to the working steam supply pipe.

The use of intermediate condensation of a mixed medium (heating steam and steam-air medium) in the condensation chamber 20 of a steam jet ejector of the first stage 18 can significantly reduce the consumption of working steam for a steam jet ejector of the second stage 19 by reducing the volume of the transported medium (vapor) entering the cavity of its mixing chamber;

- an external two-way (over heated water) shell-and-tube steam feed water heater 26 with its condensate collector 27, equipped with a level sensor (not shown).

This feed water heater (Fig. 3) has a straight-tube bundle of cooling pipes 28 with a dividing wall 29 forming a cavity 30 for collecting and subsequently removing the non-condensed vapor-air mixture (vapor) in communication with its branch pipe 31. The cavity of the annular steam volume 32 of the heater is communicated with a pipe for supplying heating steam 33 and a pipe for removing condensate 34 from its collector 27. The receiving part of the water cavity 35 of the heater is equipped with a pipe 36 for supplying sea water in communication with the pipe by the cooling water gadget 22 of the condensation chamber 21 of the steam-jet ejector of the second stage 19 (Fig. 2). The output part of the water cavity 37 is equipped with a pipe 38 for removal of heated seawater.

Moreover, this heater itself is made with the cross direction of movement of mutually heat-exchanging media.

An external two-way (over heated water) shell-and-tube steam heater 26 (Fig. 1) is designed to heat feed water (in the heating mode without evaporating the liquid) to the required temperature due to condensation of the heating steam supplied to its pipe 33 (Fig. 3), from low potential source (not shown). To maintain the temperature of such heating in it within the limits of permissible deviations from its nominal value, a temperature controller ″ T ″ is connected to the inlet steam line of the heating steam, communicated via a control pulse with a temperature sensor 39 (Fig. 1) installed on the outlet pipe connected through a pipe 38 to the output part of the water cavity 37 of the outer two-way (via heated water) shell-and-tube steam heater 26, and the temperature is controlled by changing the flow rate of the heating steam.

The vapor-air cavity 30 (Fig. 3) of this feed water heater is connected via a pipe 40 (Fig. 1) to the vapor-air cavity of the secondary steam condenser 9 of the first stage of evaporation of the evaporator 4, and its condensate collector 27, which also has a message with the condensate collector of the condensation chamber 20 of the steam-jet the ejector of the first stage 18 (figure 2), is connected to the suction cavity of the condensate pump 41, designed for pumping condensate into the condensate tank (not shown), for its reuse in the condensate cycle. At the same time, a ″ U ″ level controller is built into the pressure pipe of this pump, which is communicated by a control pulse with a level sensor (not shown) built into the condensate collector 27 of the external multi-pass shell-and-tube steam feed water heater 26 to maintain the working level in its condensate collector and stable the operation of the condensate pump 41. Moreover, an automatic three-way switching solenoid valve 42 that switches this pipeline is also installed on the output section of its pressure pipe d to discharge the condensate with its low quality by means of its connection via a control pulse with a solenometer 43 installed on the measuring branch jumper of the condensate circuit. In this case, if the permissible salt content is exceeded, the condensate is discharged overboard or into a special marine prefabricated tank of technological fresh water (not shown) for further use in technological consumers that do not have high requirements for the quality of fresh water in terms of salinity. To ensure ongoing laboratory monitoring of the quality of the condensate at the outlet pressure section of the condensate pump, a sampling valve (not shown) is integrated;

- a distillate tank 44, which is connected by its receiving pipe to the distillate collector 10 of the condenser 5 of the secondary steam of the fifth stage of evaporation of the evaporator 4, and also communicated by a pipe with a pumping distillate pump 45, while the air cavity of this distillate tank is connected by a pipe 46 with a steam-air cavity of the secondary condenser 5 a pair of the fifth stage of evaporation of the evaporator to equalize the pressure in these cavities and a reliable drain of the distillate, and the distillate tank 44 is equipped with a level sensor (not shown), communicated by a control pulse with a level regulator ″ Y ″, built into the pressure part of the piping of the distillate pump 45, to maintain the working level in the tank distillate 44 and the stable operation of the pump itself, pumping the distillate into the ship’s tank of distillate (not shown). A flow meter 47 and an automatic three-way switching solenoid valve 48 are installed at the outlet section of the pressure pipe of the pumping out distillate pump 45, which switches this pipeline to discharge the distillate at its low quality by means of its connection via a control pulse with a solenometer 49 installed on the measuring branch jumper of the distillate circuit. In this case, in case of exceeding the permissible salinity, the distillate is dumped overboard or in a special marine prefabricated tank of technological fresh water (not shown) for further use in technological consumers that do not have high requirements for the quality of fresh water in terms of salinity. To ensure ongoing laboratory monitoring of the quality of the condensate at the outlet pressure section of the condensate pump, a sampling valve (not shown) is integrated;

- brine pump 50, designed to pump overboard unevaporated brine from the brine receiver 12 of the last stage of evaporation of the evaporator 4.

At the same time, the pressure line of the brine pump has a branch jumper with a valve 51 built into the inlet pipe in front of the filter 2 of the feed pump 1, while this jumper with a valve 51 is designed to maintain the calculated temperature of the cooling water at the inlet of the secondary steam condenser 5 of the last stage of evaporation of the evaporator at swimming in cold waters by partially transferring the brine into the cooling water intake pipe.

In order to reduce the rate of scale formation on the working surfaces of the channels of the louvers of the secondary steam separators 11, throttle openings and bypass channels 13 of the switchgear, caused by the crystallization of hardness salts on the natural crystallization centers (roughness, roughness, contamination) that are always present on these working surfaces, which can become the cause of the violation of the operating mode of the OS and can even lead to the need to completely stop it, which is very significant, as part of the claimed desalination plant, to a whole, additionally administered as its constituent parts:

- a softener 52 (FIG. 4), comprising a vertical cylindrical body 53 with an elliptical cover 54 with a heating steam supply pipe 55 integrated along its axis; a perforated diaphragm 56 having holes (not shown) in its peripheral zone for organizing uniform steam supply into the water heating zone, and mounted under an elliptical cover 54; a water supply manifold 57 with dispensing nozzles 58 under which receiving contact-film water heaters 60 of confuser type arranged in the horizontal partition 59 are placed (FIG. 5); a domed horizontal partition 61 installed with an annular gap relative to the inner wall of the housing 53 on the supporting elements on these walls (not shown) and located below the horizontal partition 59; a vapor recovery manifold 62 mounted beneath a horizontally domed baffle 61; two vertical cylindrical shells 63 and 64 mounted concentrically on the elliptical bottom of the housing 65 along its axis and forming three vertical open cavities (softening sections), of which the outer cavity 66 is formed by the inner surface of the housing 53 and the outer surface of the peripheral shell 63, the middle cavity 67 is formed the inner surface of the peripheral shell 63 and the outer surface of the Central shell 64, and the Central shell 64 forms in the housing a Central cavity 68, while the upper end of the peripheral oh shell 63 is located above the upper end of the Central shell 64, and the length of both of them in height from the bottom is more than half the height of the casing of the softener. Moreover, in the lower part of the peripheral shell 63 along its perimeter, cutouts 69 are made for the flow of fluid from the external cavity to the middle; the water outlet pipe 70 is combined with the discharge of sludge particles and mounted along the axis of the elliptical bottom 65. The cylindrical body in its upper part is equipped with nozzles 71 for connecting a water indicating column for visual monitoring of the operating level, and is also equipped with a level sensor (for example, float type, not shown) .

To improve the reliability and durability of the operation of this device, a water supply manifold 57 with dispensing nozzles 58 to contact-film water heaters 60, a domed horizontal partition 61, an outlet manifold 62 and vertical shells 63 and 64 located in the most corrosive and scale-hazardous area of the softener heat-resistant hydrophobic food plastics. In this case, the manufacture of unloaded elements of the thermal softener using plastics with a lower specific gravity compared to metal provides a reduction in the mass of the device as a whole.

The softener 52 is integrated into the OS (Fig. 1) in the following order: the water supply manifold 57 (Fig. 4) is connected through a pipe on the housing 53 (not shown) with a branch 72 equipped with a control valve 73, a flow meter 74, and a level controller ″ U ″ and an integrated multi-way shell-and-tube steam feed water heater 26 (Fig. 1), which is built into the heated feed water discharge pipe from the outlet of the water cavity 37 (Fig. 3), and its heating steam supply pipe 55 is connected to the steam supply of the heating steam source ( not shown); a vapor removal header 62 through a pipe on the housing 53 (not shown) is in communication with a steam-air cavity 30 of an external two-way shell-and-tube steam feed water heater (FIG. 3); a water outlet pipe 70 with suspended sludge is in communication with a receiving pipe 75 of a two-section feed water receiver 76 (FIGS. 1, 6).

- a two-section receiver of feed water 76 (Fig. 6), installed in front of the receiver of feed water 77 of the first stage of evaporation of the evaporator 4 (Fig. 1) and comprising: a cylindrical body 78 with an elliptical cover 79 and a bottom 80, a shell 81 placed along the axis of the elliptical bottom 80 with a length of height from the bottom equal to the height of the cylindrical part of the body, and forming two vertical open cavities (softening sections), of which the outer cavity 82 is formed by the inner surface of the cylindrical body 78 and the outer surface the shell 81, and the shell 81 itself forms a central cavity 83 in the housing. In this case, the feedwater supply pipe 84 is placed along the axis of the elliptical bottom 80 and communicates with the central cavity 83, and the water supply pipe 75 with suspended sludge from the thermal softener is installed in the lower zone of the cylindrical part of the housing 78 and communicated through the tube 85 with the cavity of the Central section 83, and the pipe 86 of the water drain is built into the elliptical bottom and communicated with the receiving cavity of the feedwater receiver 77 of the first stage of evaporation of the evaporator 4 (Fig.1). On the axis of the elliptical cover 79, a nozzle 87 for venting air is built into it. The cylindrical housing 78 in its upper part is equipped with nozzles 88 for attaching a water indicating column for visual monitoring of the operating level (not shown), and is also equipped with a level sensor (not shown).

A two-section feed water receiver is integrated into the OS in the following order: the outer cavity 82 by a branch pipe 86, located in its lower zone, is in communication with the pipe for supplying the aqueous medium of the tank water receiver 77 (Fig. 1) of the first stage of evaporation of the evaporator, and the central cavity 83 with a pipe supply 84 of feed water in the lower zone is connected to a discharge pipe of the output part of the water cavity 37 of the external multi-pass shell-and-tube steam heater (Fig. 3), and is also in communication with the pipe for discharging water 70 with suspended sludge termoumyagchitelya (4) for their mixing quality, i.e. for averaging the concentration of “seed” sludge particles in the liquid volume in the Central cavity, which is an indispensable condition for the implementation of effective softening of feed water in the outer section of the two-section receiver. To maintain a constant working level, the two-section feed water receiver is equipped with a level sensor (for example, a float type, not shown) connected by a control pulse to a ″ U ″ level regulator built into the heated feed water supply pipe connected to it with an outlet pipe 38 of an external multi-pass shell-and-tube steam heater (figure 3).

As part of the inventive desalination plant (figure 1), as a whole, these additional components are intended for the implementation of two technologically interconnected processes. So, the softener 52 is a technological device for generating particles of mobile sludge in a volume of a solution supersaturated with scale-forming salts, which are subsequently used as “seed crystals” in a two-section receiver of feed water 76 to reduce the supersaturation of hardness salts in feed water of the first stage of evaporation of evaporator 4 due to sludge formation in the volume of hardness of saturated feed water supersaturated with salts (thermal softening).

The inventive multistage adiabatic desalination plant (DU) is used as follows (figure 1).

Outboard (feed) water (at a temperature of t _o = 28 ° C with a concentration of scale-forming salts C _о , mEq / l) is supplied by a circulation feed pump 1 through its filter 2 and a flow meter 3 into a receiving water cavity (not shown) of shell-and-tube cooling pipes the secondary vapor condenser 5 of the fifth stage of evaporation of the five-stage adiabatic evaporator 4 (hereinafter referred to as the "evaporator"). Further passing sequentially in the cooling pipes of the secondary steam condensers 5-6-7-8-9 of the evaporator in the direction from the fifth stage of evaporation to the first, sea water increases its temperature due to the heat of condensation of the secondary water vapor. Such a scheme of movement of cooling water allows sufficiently fully regenerate the heat of condensation of the secondary vapor in the evaporation stages.

From the secondary steam condenser 9 of the first stage of the evaporator, cooling water passes through the cooling pipes 22 (Fig. 2) of the condenser 17 of the two-stage steam-jet ejector with separate condensation chambers 20 and 21 of the steam-jet ejectors of the first 18 and second 19 stages, where it is heated due to the heat of condensation mixed vapor-air medium (working steam and steam-air mixture from the secondary steam condensers) of steam-jet ejectors, and enters the receiving part of the water cavity 35 (Fig. 3) of an external multi-pass shell-and-tube steam heater 26, where the feed water is heated in the heating mode without evaporating the liquid (to a temperature not exceeding t ₁ = 77 ° C) due to the heat of condensation of the heating steam supplied to its vapor cavity 32 from a low-potential steam source (not shown), (for example, steam from auxiliary turbines at an operating pressure of 0.8 atm).

In this case, the rate of scale formation in the mentioned OS elements along the path of heated feed water, uniquely determined by the heat stress and temperature of the heat transfer pipes, is greatest in the external multi-pass shell-and-tube steam heater 26 (Fig. 1), which ultimately determines the need to limit the heating temperature of the feed water , to ensure the scale formation rate that is permissible under operating conditions, due to the use of a low-potential source of heating steam (not shown). Therefore, to prevent excessive heating of the feed water in the pipeline in communication with the outlet water cavity 37 (Fig. 3) of this external multi-pass shell-and-tube steam heater 26, a temperature sensor 39 is installed that controls the operation of the temperature controller Т T ’integrated into the supply steam line of a low-grade source of heating steam (not shown) and ensuring the maintenance of a given temperature of heating the feed water by changing the flow rate of heating steam.

From the outlet water cavity 37 of the external multi-pass shell-and-tube steam heater 26, heated seawater enters the lower zone of the central section 83 (Fig. 6) of the two-section feedwater receiver 76, and part of this water through the branch 72 with a control valve 73, a flow meter 74, and a level regulator ″ Y ″ enters the collector for supplying an aqueous medium 57 (Fig. 4) of a softener.

In the softener 52, by supplying heating steam, additional heating of seawater taken from branch 72 from the feed water supply line is carried out, which contributes to an increase in its supersaturation with scale-forming salts and creates conditions for the efficient generation of mobile sludge particles in the volume of the supersaturated solution, which are used in the future as ″ seed crystals ″ to reduce the supersaturation in the volume of heated sea water in a two-section receiver of feed water 76 due to sludge formation (thermal of softening) on these "seed crystals".

To maintain a constant working level in the temperature softener 52, it is equipped with a level sensor (not shown), connected by a control pulse to a level control “U”, built into the mentioned branch 72, which also contains a control valve 73 and a flow meter 74. The temperature softener 52 is also equipped with a water indicating column ( not shown) on the nozzles 71 for visual inspection of the operating level.

From the heat softener 52, water with suspended sludge through the pipe for discharging the aqueous medium 70, built along the axis of the elliptical bottom 65 (Fig. 4), and the pipeline connected with it, through the pipe 75 and pipe 85 enters the central cavity 83 of the two-section feed water receiver (Fig. 6), where due to mixing with the main stream, averaging of the concentration of sludge particles in the volume of feed water is achieved, which is a prerequisite for ensuring an effective decrease in the concentration of hardness salts (thermal softening) in the feed water e due to the bulk sludge formation in the outer cavity 82 twopart receiver feedwater mode downflow fluid motion.

The discharge of softened water with suspended sludge from the body of the two-section feed water receiver 76 is carried out through a pipe 86 connected to its external cavity 82, and then, through a pipe connected to this pipe 86, it enters the feed water receiver of the first evaporation stage 77 of the evaporator 77 (Fig. 1 ), the volume of which is also used as an additional section of thermal softening. In this case, the two-section receiver of feed water 76 in the upper part of the cylindrical body 78 (Fig.6) is equipped with a water indicating column (not shown) on the nozzles 88, for visual control of the operating level. To maintain a constant working level in this two-section receiver, it is also equipped with a level sensor (not shown) communicated by a control pulse with a ″ U ″ level regulator built into the feed water supply pipe.

From the feed water receiver 77 of the first stage of evaporation of the evaporator 4, through the bypass pipes 13 of the throttle-spraying devices (DRU) connected to it, the softened feed water with suspended sludge enters the vacuum chamber of the first stage of evaporation of the evaporator 4. Bypass of the brine in the first stage of evaporation throttle atomization and partial evaporation in the second stage of evaporation is carried out from the brine receiver 12 of the first stage of evaporation through the bypass pipes 13 connected to it, connected to second-stage spraying device for vaporization. Bypass and spraying of the brine in the subsequent evaporation stages of the evaporator is carried out from the brine receiver 12 of the previous evaporation stage through the bypass pipes 13 connected to them, connected to the throttle-spray devices of the subsequent evaporation stage. Moreover, these processes occur due to the pressure difference between the stages of evaporation. These bypass pipes contain built-in throttling devices (not shown) in their upper free part, above the upper cut of which mushroom-shaped chippers 14 are located, which act as reflectors of “fountain” jets of water flowing from the holes of the throttle device, which provides drip spraying of the overheated brine and creates conditions for its effective evaporation.

The resulting secondary steam rises up in the evaporation stages of the evaporator 4 and, passing through the louver type secondary vapor separator 11 of this evaporation stage, where brine droplets captured by rising secondary steam are separated, condenses in the condenser of the same evaporation stage, which occurs due to the removal of cooling heat water. The non-condensing vapor-air mixture from the respective cavities of the secondary steam condensers is sequentially bypassed in the direction from the secondary steam condenser 9 of the first evaporation stage to the secondary vapor condenser 5 of the fifth evaporation stage through the system of interstage throttle washers 15 built into these serial bypass pipes and is sucked out with a two-stage steam jet ejector and 19, integrated in the capacitor 17 (FIG. 2) of a two-stage steam-jet ejector with separate condensation chambers 20 and 21 of the air-vapor mixture, respectively, from the ejectors of the first 18 and second 19 stages, forming together with series-connected pipes of cooling water 22 in them refrigerators-condensers with their condensate collectors, interconnected by a U-shaped pipe 23, designed to create a hydraulic shutter between them . In this case, the transported medium from the vapor-air cavity of the secondary steam condenser 5 (Fig. 1) of the fifth stage of evaporation of the evaporator enters the receiving cavity of the mixing chamber of the steam jet ejector of the first stage 18, the output diffuser of which is in communication with the vapor-air cavity of the condensation chamber 20 of the condenser of the steam condenser ejector of the first stage 18, from where the non-condensed part of the mixed medium (vapor) enters the cavity of the mixing chamber of the second-stage steam jet ejector 19, and the output diffuser of the second ejector tupeni condenser 19 communicates with a steam ejector air-steam condensation chamber cavity 21 of the second stage 19, from which the vapors (air) through the pipe 25 is removed to the atmosphere, wherein the inlet nozzle portion of these two eductors connected in parallel to the feed line working steam. Such a scheme for diverting the vapor-air mixture from the secondary steam condensers using intermediate condensation of the mixed medium in the condensation chamber of the first-stage steam-jet ejector allows significantly reducing the consumption of working steam on the second-stage steam-jet ejector by reducing the volume of the transported medium entering the cavity of its mixing chamber.

A stepwise increasing working vacuum in the evaporation stages of the evaporator 4 is provided due to the condensation of the secondary vapor in the condensers of the corresponding evaporation stages and the operation of the two-stage steam-jet ejector 18 and 19, sucking the vapor-air mixture from the vapor-air cavity of the condenser 5 of the secondary steam of the fifth stage of the evaporation of the evaporator 4 through the system washers 15 embedded in the pipes of their serial bypass.

In this five-step adiabatic desalination plant (OU), the absolute pressure in the evaporation stages decreases stepwise from 0.318 ata (in the first stage) to 0.084 ata (in the fifth stage), which corresponds to saturation temperatures of 70 and 42 ° C, and the same temperature difference is maintained saturation of the evaporated brine 7 ° C in all adjacent stages of evaporation, which ensures the same performance of the stages of the evaporator (2 t / h).

The resulting distillate moves in the desalination unit in the direction from the secondary steam condenser 9 of the first evaporation stage to the fifth 5 by gravity due to the pressure difference between the evaporation stages by sequentially transferring these condensers from the distillate collectors through communicating U-shaped pipes 16. At the same time, the calculated working differential pressure between the stages of evaporation of the evaporator is supported by the height of the liquid column in these U-shaped pipes, which uniquely determines the temperature difference I vaporized brine in these adjacent levels of evaporation of the evaporator.

The distillate obtained in the desalination unit is discharged from the distillate collector 10 of the fifth vaporization condenser 5 of the fifth evaporation stage through a pipe connected to the distillate tank 44, the vapor cavity of which is connected by a pipe 46 to the vapor-air cavity of the fifth vaporization condenser of the fifth vaporization stage 5 to equalize the pressure in the marked cavities and ensure reliable distillate runoff. From the tank 44, the distillate is pumped out by a distillate pump 45 into a general vessel distillate tank (not shown) for its subsequent use in technical, technological and domestic consumers.

The distillate tank 44 is equipped with a level sensor (not shown), communicated by a control pulse with a ″ U ″ level regulator, built into the pressure pipe of the pump for distillation pump 45, to maintain a constant working level in this tank and ensure stable operation of the pump itself. At the same time, a flow meter 47 and an automatic three-way switching solenoid valve 48 installed at the outlet section of the discharge pipe of the pumping out distillate pump 45 switch this pipeline to discharge the distillate at its low quality by means of its connection via a control pulse with a solenometer 49 installed on the measuring branch jumper of the distillate circuit. In this case, if the permissible salinity is exceeded, the distillate is discharged overboard or into a special marine prefabricated tank of technological fresh water (not shown) for further use in technological consumers that do not have high requirements for the quality of fresh water in terms of salinity.

To ensure routine laboratory quality control of the distillate, a sampling valve (not shown) is built into the outlet pressure section of the distillate pump 45.

The condensate formed from the condenser 17 of the two-stage steam-jet ejector 18 and 19 enters from the condensation chamber 20 (Fig. 2) of the steam-jet ejector of the first stage 18 into the condensate collector 27 of the multi-way shell-and-tube steam heater 26 connected to it, from where together with the condensate formed in its cavity of the steam volume 32 heating steam is pumped by a condensate pump 41 into a condensate tank (not shown) for subsequent use in a steam condensate cycle of a power plant.

The condensate collector 27 of the shell-and-tube steam heater 26 is equipped with a level sensor (not shown) communicated by a control pulse with a ″ У ″ level regulator integrated in the pressure pipe of the condensate pump 41, which maintains a constant working level in this collector and ensures stable operation of the pump itself. At the same time, an automatic three-way solenoid valve 42 installed at the outlet section of the discharge pipeline of the pumping-out condensate pump switches this pipeline to discharge the distillate at its low quality by means of its connection via a control pulse with a straw meter 43 installed on the measuring branch junction of the condensate circuit. In this case, if the permissible salt content is exceeded, the condensate is discharged overboard or into a special marine prefabricated tank of technological fresh water (not shown) for further use in technological consumers that do not have high requirements for the quality of fresh water in terms of salinity.

To ensure ongoing laboratory monitoring of the quality of the condensate, a sampling valve (not shown) is integrated in the outlet pressure section of the condensate pump 41.

An unevaporated brine with coarsened sludge particles (at a temperature of t ₃ = 42 ° C) is removed overboard from the brine receiver 12 of the last stage of evaporation of the evaporator by the brine pump 50, the pressure pipe of which has a jumper with valve 51, built into the pipe in front of the feed pump 1. This recirculation jumper is used to maintain the design temperature of the cooling water at the inlet to the condenser 5 of the secondary steam of the fifth evaporation stage when swimming in cold waters by partial bypass ssola a cooling conduit (nutrient) water.

In the heat softener (figure 4), as part of the whole OS, the technological process for the generation of mobile particles of sludge volume of the supersaturated solution is as follows.

Sea water, partially withdrawn from the pre-heated feed water supply line through a branch 72, containing a control valve 73, a flow meter 74 and a “U” level regulator (Fig. 1), is supplied to a water supply manifold 57 with dispensing nozzles 58 to contact water heaters of confuser type 60, built into the horizontal partition 59, where it flows in film mode on the inner confuser surface (figure 5). The heating steam through the pipe 55, placed along the axis of the elliptical cover 54, is fed into the heating zone through a perforated diaphragm 56, having holes (not shown) in its peripheral zone and placed horizontally under the elliptical cover 54, uniformly flows to contact water heaters of confuser type 60, where due to condensation of the heating steam on the free surface of the gravitationally flowing liquid film, its effective heating is ensured. Such contact heating using a confuser 60 made of low-heat-conducting material ensures a minimum temperature in the near-wall layers of the liquid, which is extremely important for creating conditions for a non-scale operation of the contact water heater itself.

Further contact heating is carried out in the mode of an annular jet-film flow of liquid at the outlet of a water heater of confusor type 60 (Fig. 5) in a satellite-transverse mode of movement of heating steam. Heated water enters the outer surface of the horizontal domed septum 61 and flows in the form of jets into the outer thermal softening section 66 formed by the inner surface of the housing 53 and the peripheral shell 63. In this section, water is heated by condensation of heating steam on the outer surfaces of the jets that are subsequently streamlined by it water. Throughout the path of its transversal movement, the heating steam provides “ventilation” of the free surfaces of the heated fluid, helping to remove the released gases through the vapor exhaust manifold 62, which is located under the horizontal domed partition wall 61. At the same time, the vapor-air mixture exhaust manifold is placed under the horizontal domed partition wall 61, which has the maximum area in the lower cross section, and taking into account that the flow rate of the vapor removed by changing the direction vector by 90 ° does not exceed 3-5% of the flow rate of heating steam eliminates droplet removal saline together with moisture evaporated and allows directing vapors in the corresponding capacitor (namely, 26) for subsequent return condensate in the steam-condensate cycle.

This scheme of organizing additional heating of the liquid in the mode of satellite-transverse movement of heating steam in combination with active ″ ventilation ″ of the free surfaces of the heated water determines an increase in the partial pressure of the vapor at the interface, thereby minimizing the liquid’s under-heating to the saturation temperature corresponding to the pressure in the case of the softener , which helps to achieve maximum supersaturation of the solution on scale-forming salts at the entrance to the outer section 66.

Particles of vapor trapped by jets of liquid flowing down from the domed septum 61 create an area saturated with steam bubbles in the upper zone of the external thermal softening section 66, which moves downward along with the liquid. In this case, steam bubbles of various sizes perform various functions during the movement of the solution in this external section of thermal softening. So large vapor bubbles contribute to the degassing of the heated liquid due to the diffusion of the released gases into their volume, and as they grow, these steam bubbles float up to the ventilated phase boundary, helping to remove gases together with the vapor. At the same time, the smallest vapor bubbles, acting as crystallization centers in the volume of a supersaturated solution, serve as a catalytic factor in the formation of nuclei of primary particles of sludge in the volume of a supersaturated solution in the outer softening section. Along with the noted processes in the volume of the heated supersaturated solution in the outer section 66 of thermal softening, there is also a natural formation of crystallization centers (nuclei of the primary particles of the sludge) by reducing the supersaturation of the liquid.

In the solution volume of the subsequent thermal softening sections: middle 67 and central section 68, the primary particles of sludge (sludge formation) grow in the volume of the solution of the external thermal softening section 66, the main criterion for evaluating the effectiveness of the thermal softener is the number and size of slurry particles at the output of the device .

Moreover, due to the manufacture of a horizontal domed septum 61, peripheral 63 and central 64 shells made of plastics with hydrophobic properties, the scale deposits on the outer surface of the domed horizontal surface and the vertical surfaces of the cylindrical shells are worsened, which prevents the solution from being supersaturated due to scale formation on these surfaces before its entry into the outer section 66, as well as in the softening sections themselves in the direction of movement of the supersaturated solution a, which is an additional factor contributing to improve the efficiency of generation of sludge particles, which are main target termoumyagchitelya technological products.

The described processes for the generation of mobile sludge particles in the volume of a supersaturated solution of the thermal softener are illustrated graphically in Fig.7.

The intensity of generation of sludge particles in the volume of a supersaturated solution, based on the use of negative solubility of hardness salts, increases with increasing temperature of the heating fluid, due to an increase in its supersaturation. Therefore, the use of additional heating of the liquid supplied to its inlet from the pipeline of feed water heated in the heater 26 with a concentration of hardness salts C ₁ , mEq / l, is a factor intensifying the process of formation of sludge particles here. Moreover, the nature of the decrease in the supersaturation of the solution (kinetics of thermal softening) due to sludge formation in its volume, and the degree of completion of the process of thermal softening (number and size of sludge particles) depend on the hydrodynamic regime of fluid movement (laminar, laminar-turbulent, turbulent) and residence time solution in the softener.

In the turbulent mode of movement of the solution (ideal mixing mode), in which, due to the active removal of liquid from the zone with less supersaturation of the solution into the zone with increased supersaturation, there is a general decrease in the supersaturation of the softened solution along its movement in the softener, which, ultimately, predetermines a decrease in the intensity of formation and growth of sludge particles (line C _pc = f (τ)) as a whole and does not meet the requirements for ensuring efficient generation of sludge particles.

The ideal mode for the generation of suspended sludge particles in a heat softener is the laminar mode of movement of the softened solution (ideal displacement mode), in which, due to the lack of mixing of the liquid, the greatest efficiency of formation and growth of sludge particles is achieved under conditions of the highest concentration potential for effective sludge formation during thermal softening of the solution in the softener. In this case, the decrease in the supersaturation of the solution is determined only by the sludge formation processes and the residence time of the solution in the thermal softener (line C _pb = f (τ)). However, the practical implementation of this ideal option is quite complicated and involves the use of a thermal softener with significantly larger sizes.

Therefore, the use of sectioning the water volume, which excludes mixing of the liquid in the entire water volume of the heat softener and provides the possibility of laminarization of the moving liquid in the softening sections by reducing the speed of its movement, creates favorable conditions for the efficient generation of sludge particles with a smooth (as a result of sludge formation) decrease in the degree of supersaturation of the solution in direction from the outer softening section to the central one (line 0-1-2-3), where τ ₁ , τ ₂ , τ ₃ is the residence time of the supersaturated solution in the corresponding softening sections in the sequential alternation of the lowering and lifting movements, which makes it possible to bring the intensity of these processes closer to the ideal (laminar) version (line C _pb = f (τ)). In this case, the outermost section 66 of thermal softening is characterized by the greatest intensity of reducing the supersaturation of the solution, where intensive processes of nucleation of slurry particles occur under conditions of the greatest supersaturation of the solution and the presence of the smallest slurry bubbles, which serve as catalysts for these processes as crystallization centers. In the subsequent softening sections (middle and central), the intensity of the decrease in the supersaturation of the solution weakens due to a decrease in the concentration potential for the growth of sludge particles generated in the external section of thermal softening.

It is known that with increasing number of sections the achieved depth of thermal softening will increase. However, it must be borne in mind that in additional sections of softening, the processes of growth of sludge particles will proceed in the zone with lower supersaturation of scale-forming salts, which also determines the low growth rate of sludge particles. Therefore, the additional effect achieved by increasing the number of softening sections, associated with a significant complication of the design and the deterioration of the weight and size characteristics of the thermal softener, will be insignificant.

In this regard, it is significant that in the claimed three-sectional embodiment of the softener, the size of the slurry particles at the device output, required for their subsequent effective use as “seed crystals”, is provided by changing the height of the water volume of the device (increasing the generation time of sludge particles) without changing it lateral dimensions, which is extremely significant.

The functional purpose of these sections of thermal softening is different, therefore, to organize the effective generation of sludge particles, a rational distribution of the total water volume of the thermal softener between the sections of thermal softening was performed, namely:

- in the outer section 66, under conditions of maximum supersaturation of the solution, due to its additional heating, and the presence of the smallest vapor bubbles, which act as crystallization centers, the primary nuclei intensively form crystallization centers and begin to grow (sludge formation). At the same time, the overall efficiency of the heat softener is determined by the efficiency of the organization of processes in this section, which is achieved by increasing the residence time and lowering the speed of the lowering movement of the solution. Therefore, the water volume of the outer section is the largest (at least half of the total water volume of the thermal softener);

- in the middle section 67 in the lifting mode, further growth and enlargement of sludge particles coming from the outer section 66 occurs, as a result of which their total surface increases. In this case, the use of a single aqueous medium, which predetermines the identity of the chemical composition of the primary nuclei of the crystallization centers generated in the volume of the outer section 66, to the chemical composition of the softened solution, results in less crystallization on these “seed” sludge particles in the volume of the supersaturated solution. Thanks to the noted catalytic factor, the effective growth of slurry particles in the volume of the solution of this section of thermal softening is ensured.

In the volume of the middle section for the effective growth of sludge particles in the volume of the supersaturated solution, laminarization of the fluid flow in the mode of its lifting movement is also required, which is achieved by ensuring the corresponding speed of movement and the residence time of the softened solution in it. As a result, the middle section 67 is made with a volume that occupies at least a third of the total water volume of the softener;

- in the central section 68 in the mode of lowering the movement of liquid, the growth of slurry particles continues and ends at a stage sufficient for their further use as “seed crystals” in the two-section receiver 76 of the feed water of the evaporator. At the same time, the growth rate of slurry particles in the volume of this section, occurring in the zone with the lowest supersaturation of the solution, will be lower than in the middle section 67, therefore, the main additional purpose of this central section is to provide water with the highest content of suspended slurry particles from its lower zone at the entrance of a two-section receiver of feed water 76.

To ensure the stable operation of the heat softener, it is necessary to maintain an optimum working fluid level in it, while the limit range of the fluid level control zone is limited by the maximum upper and lower permissible fluid levels, which are determined respectively by the height of the upper edge of the intermediate shell 63 and the overflow edge of the central shell 64. For this purpose the softener is equipped with a water indicating column (not shown) on the nozzles 71 for visual level control, and is also equipped with a level sensor vnya (not shown).

Thus, a part of the whole (OS) in the aggregate of its distinctive features is proposed, namely:

- inclusion in the composition of the softener of additional structural elements: a horizontal perforated diaphragm 56, a horizontal domed partition 61 with a vapor collector 62 mounted beneath it;

- the use of partitioning of the water volume and the organization of thermal softening processes in the direction from the outer softening section 66 to the central 68 in the sequential alternation of the lowering and lifting laminarized fluid movement in the softening sections, ensuring the removal of the aqueous medium with the highest content of generated particles of mobile sludge from the lower zone of the central section thermal softening through the pipe 70;

- the use of additional effective contact heating of the softened solution in the mode of transverse-lateral movement of the heating steam, providing maximum supersaturation of the solution with hardness salts at the inlet of the external thermal softening section 66, which improves the generation efficiency of primary slurry particles in the volume of this section in the presence of the smallest vapor bubbles performing a catalytic function as crystallization centers in the formation of primary sludge particles;

- the manufacture of a horizontal domed septum 61, peripheral 63 and central 64 shells of plastics with hydrophobic properties that worsen the conditions of scale deposition on the outer surface of these elements of the thermal softener and prevent the solution from being supersaturated due to scale formation on these surfaces before it enters the external thermal softening section 66 , as well as in the softening sections themselves in the direction of movement of the supersaturated solution, which serves as an additional factor contributing to increase the efficiency of the generation of sludge particles;

- the use of a single aqueous medium, predetermining the identity of the chemical composition of the primary nuclei of the crystallization centers generated in the volume of the outer section 66, to the chemical composition of the softened solution, resulting in less crystallization on these “seed” sludge particles in the volume of the supersaturated solution.

The noted positive factors in their totality allow us to sufficiently realize the technological tasks assigned to the heat softener for the efficient generation and removal of sludge particles for their further use as “seed crystals” in order to reduce the supersaturation of the solution in the volume of a two-section receiver of feed water.

Two-section receiver of feed water 76 as part of the inventive OS is as follows (Fig.6).

Heated feed water is supplied to the pipe 84 for supplying an aqueous medium located in the lower zone of the central section 83 of this two-section receiver of feed water through a discharge pipe connected to the outlet of the water cavity 37 (FIG. 3) of the external multi-pass shell-and-tube steam heater 26 (FIG. 1) . Water with suspended sludge from the thermal softener 52 is also supplied to the cavity of the central section 83 of this two-section receiver through a pipe 75 and a pipe 85 located in the lower part of its body (Fig. 6). Such a scheme for supplying two aqueous media ensures their high-quality mixing, i.e. averaging the concentration of “seed” slurry particles in the liquid volume in its central section 83 in the mode of its lifting movement, which is an indispensable condition for the effective implementation of thermal softening processes in the outer section 82 of the two-section receiver of feed water in the mode of lowering the movement of liquid entering the cavity of this section by overflowing over the upper edge of the additional shell 81 from the central section 83. In this case, the main factors determining the effectiveness of the thermal softening process (sludge formation) in the water volume of the outer section 82, are similar to the intensifying factors set forth in the description of the operation of the thermal softener.

In particular, due to the use of the central section 83 for mixing aqueous media in a two-section receiver 76, mixing in the volume of softened solution in its outer section 82 is eliminated, which makes it possible to realize effective thermal softening of feed water using “seed” slurry particles in a laminarized stream lowering movement mode. Moreover, the use of an aqueous medium for generation of slurry particles in a heat softener 52 taken from the feed water supply line determines the identity of the chemical composition of these slurry particles to the chemical composition of the solution softened in a two-section receiver 76, which leads to less crystallization work on the said “seed” slurry particles in the volume of a supersaturated solution, i.e. is an additional factor stimulating effective sludge formation (increase in the size of primary sludge particles) in the volume of the solution of its outer section 82 by reducing its supersaturation in the direction of the lowering movement. The achieved depth of thermal softening (concentration of hardness salts at the output of the device 76) is determined by the residence time of the solution in its external softening section, i.e. its volume. Therefore, for the most efficient use of the volume of the outer section 82 of thermal softening of the two-section receiver 76, the additional shell 81 forming the central section 83 is made with a height of its height equal to the height of the cylindrical part of its body 78. In this case, air is exhausted when the device is filled through a nozzle 87 located along the axis of the elliptical cover 79 of the housing of this two-section feed water receiver and connected to the pipeline with an air valve (not shown en). At the same time, to maintain an optimal working level, it is equipped with a level sensor (not shown), communicated by a control pulse with a ″ U ″ level regulator, integrated in a heated feed water pipe leading from the heater 26, in communication with its pipe 84.

Thus, the proposed two-section receiver of feed water in the aggregate of its distinguishing features, namely, the partitioning of the water volume of the two-section receiver of feed water, can optimally solve the two-part technological task of organizing effective mixing of water flows with suspended sludge from the thermal softener 52 (Fig. 1) and softened feed water (in the central section 83), and subsequent thermal softening of this mixed aqueous medium (in the outer section 82).

Softened feed water with suspended sludge is discharged from the lower zone of the cavity of the outer section 82 of the housing through a pipe 86 built into the elliptical bottom 80, and is fed to the input of the feed water receiver 77 (Fig. 1) of the first evaporation stage of the evaporator 4 (Fig. 1). Moreover, its volume is used as an additional softening section of a two-section receiver of feed water, which allows to achieve a greater depth of softening of feed water, which is very important for the implementation of the general inventive concept to reduce the rate of scale formation in the elements of the desalination plant.

The effectiveness of the additional inclusion of a two-section receiver of feed water 76 in the OS (figure 1) is due to the following.

The feed water receiver of the first evaporation stage of the known OA evaporator, containing a cylindrical body with a lid and an elliptical bottom and equipped with water supply and outlet pipes, does not meet the requirements for effective softening of the supersaturated solution on “seed” slurry particles generated in the thermal softener (in case of direct connection to the thermal softener), due to the limited water volume and, consequently, the duration of thermal softening processes. At the same time, the single-sectional design of the feedwater receiver does not provide a simultaneous high-quality solution to two related problems: efficient mixing of “seed” sludge particles in the volume of a supersaturated solution and the implementation of effective softening of a supersaturated solution, i.e. in a single-sectional design of the feedwater receiver of the first stage of evaporation of the evaporator, performing mainly the function of a mixer of “seed” slurry particles in the volume of a supersaturated solution, it is not possible to sufficiently realize the main goal of the inventive concept of the claimed invention to reduce the supersaturation of feed water at the entrance to the evaporator.

Thus, the proposed two-section receiver (6) of feed water in the aggregate of its distinguishing features, namely: sectioning of the increased water volume by installing an additional shell 81 with a length along its height from the bottom equal to the height of the cylindrical part of the housing, which allows to optimally solve the dual technological the task of effectively mixing water flows with suspended sludge from a heat softener and softened feed water (in the central section 83), as well as the implementation of subsequent effective thermal softening of this mixed aqueous medium (in the outer section 82) in the mode of laminarized lowering movement of softened feed water, which, together with the use of the volume of the receiver 77 (Fig. 1) of feed water of the first stage of evaporation of the evaporator as an additional softening section, ensures the achievement of the set technical task to ensure effective reduction of feedwater supersaturation, in particular at the inlet of the first stage of evaporation of the evaporator, assigned to this additional th element of the claimed desalination plant.

Due to the inclusion in the composition of the proposed desalination plant, as a whole, of its technologically interconnected additional components: a thermal softener 52, which ensures the efficient generation of mobile slurry particles and their subsequent use in a two-section receiver of feed water 76 as “seed crystals” to reduce feed water supersaturation in it for hardness salts, and also due to the use of the volume of the feedwater receiver 77 of the first stage of evaporation of the evaporator as a supplement ln the thermal softening section, a decrease in the concentration of scale-forming salts in the feed water containing the slurry suspended in it at the inlet of the evaporator is achieved, which is essential for the implementation of the general inventive concept to reduce the rate of scale formation in the elements of the desalination plant.

In particular, bypassing through pipes 13, throttle atomization, and evaporating such softened feed water in the first stage of evaporation of the evaporator, favorable conditions are created for reducing the rate of scale formation in the bypass channels and working surfaces of the throttle-spraying devices (DRU) by reducing the concentration of scale-forming salts in the nutrient water at the entrance to the first stage of evaporation, as well as on the surfaces of the working channels of the louver separator 11 of the secondary steam by reducing the salt content of droplets lags introduced therein a secondary evaporation stage of the steam. Moreover, in the volume of non-evaporated liquid (brine) contained in the bottom zone of the evaporation chamber of the first stage of the evaporator and the brine collector 12 of the second stage of evaporation, the processes of thermal softening of the brine occur due to the growth of sludge particles present in the volume of the brine.

Bypassing such a softened brine for spraying and subsequent evaporation in the second stage of evaporation of the evaporator, the scale formation rate on the working surfaces of the bypass pipes 13 and the openings of the differential switchgear decreases due to a decrease in the concentration of hardness salts in the brine, and also due to the replacement of surface scale formation by volumetric sludge formation with “seed” slurry particles contained in the volume of brine. The prevailing nature of volumetric sludge formation over surface scale formation here is due to the absence of overheating of the wall layers of the liquid (lack of heat supply), as well as the large total surface of the slurry particles, significantly exceeding the total surface of the natural crystallization centers on the working surfaces of the mentioned evaporation stage elements. Similarly, processes occur in subsequent stages of evaporation of the evaporator with sequential bypass, throttle atomization and evaporation.

The physical processes occurring during the operation of the OS are illustrated graphically in Fig. 8.

Seawater with an initial concentration of dissolved scale-forming salts C _o , mEq / l at a temperature of t _o , ° C enters the input of the secondary vapor condenser 5 of the fifth stage of evaporation of the evaporator 4.

When sequentially passing through the cooling pipes of the secondary steam condensers 5–9 at all stages of evaporation of the evaporator 4, the condenser 17 of the two-stage steam jet ejector and the external multi-pass shell-and-tube feed water heater 26, it is successively heated to the temperature t ₁ , ° C due to the heat of condensation in the condensers of the secondary steam in stages of evaporation, heat of condensation of the steam-air mixture and working steam of steps of steam jet ejectors, as well as heat of condensation of the heating steam feed water heater. Due to an increase in the supersaturation of scale-forming salts in it (С _о -С _p ), mEq / l, due to a decrease in the solubility of hardness salts with increasing temperature C _p = f (t), where С _p = _f (1) is the functional dependence of the equilibrium concentration hardness salts from the temperature of the liquid, scale deposits on the heat exchange surfaces of the mentioned OS elements, which leads to a decrease in the concentration of scale-forming salts at the outlet of the external multi-pass shell-and-tube feed water heater to C ₁ , mEq / l (line 0-1). At the same time, the rate of scale formation, uniquely determined by the heat stress and temperature of the heat transfer pipes, is the highest in the external shell-and-tube steam feed water heater.

Feed water from an external shell-and-tube steam feed water heater at a temperature of t ₁ and with a concentration of dissolved hardness salts c ₁ , mEq / l passes sequentially through a two-section receiver 76 and a feed water receiver 77 of the first stage of evaporation of the evaporator, where at a constant temperature the concentration of dissolved salts stiffness in it decreases to a concentration of C ₂ , mEq / l (line 1-3) due to volumetric sludge formation on “seed” sludge particles generated in the thermal softener. Softened feed water with suspended sludge through the bypass pipes 13 of the throttle-spray devices of the first evaporation stage through the feedwater 77 connected to the receiver of the feed water enters the first stage of vacuum evaporation with a saturation temperature in the evaporation chamber t ₂ and the same concentration of C ₂ , mEq / l ( line 3-4). During sequential interstage bypass, throttle spraying and adiabatic evaporation of the brine, the suspended sludge contained in it is used as “seed crystals” to reduce the supersaturation of the brine (contained in the bottom zone of the evaporator evaporation stages and in the volume of their brine receivers of the second and subsequent evaporation stages) due to volumetric sludge formation in the brine along its stepwise bypass (line 4-6), and these processes proceed under conditions of successive stepwise decrease saturation temperature of evaporation stages and ends at t ₃ corresponding to the saturation pressure of the fifth stage evaporator evaporation at a concentration of hardness salts in the brine, with some decrease in hardness concentrations below C ₂ mEq / l.

For comparison, Fig. 8 simultaneously shows the nature of the change in the supersaturation of the solution in the known desalination plant (line 1-2-5), where line 1-2 is the process of throttling and vacuum evaporation in the first stage of the evaporator; line 2-5, the process of throttling and vacuum evaporation in subsequent stages of evaporation. The decrease in brine supersaturation (at elevated concentrations) in the evaporation stages is caused precisely by scale formation on the working surfaces of the switchgear and channels of the louvered separators of the secondary pair of evaporator evaporation stages, which reduces their working life.

Figure 9 shows a graphical representation of the nature of the physical processes taking place in the five-step adiabatic evaporator itself.

In a known desalination plant, the feed water enters the evaporation chamber of the first stage of the evaporator from the feed water receiver with a concentration of dissolved salts of hardness C ₁ , mEq / l (which is much higher than C ₂ , mEq / l) through throttling pipes connected to it -spray devices of this evaporation stage, where it evaporates due to the heat of overheating in a vacuum mode at the same saturation temperature t _2, ° C (Fig. 8).

Moreover, due to the stepwise decrease in the saturation temperature in the evaporation stages of the evaporator, the solubility of hardness salts in the brine C _p = f (τ) increases stepwise in them, where C _p = f (τ) is the functional dependence of the equilibrium concentration of hardness salts on the liquid temperature by the entrance of the evaporation stages, which leads to a corresponding decrease in its supersaturation ΔC _n , mEq / l (here the index ″ n ″ corresponds to the number of the evaporation stage) in the evaporation stages (Fig. 9). However, this positive factor, due to the stepwise decrease in pressure (saturation temperature) in the evaporation stages, does not allow for a significant decrease in the rate of scale formation on the working surfaces of the interstage bypass pipes of the throttle-spray devices, as well as on the surfaces of the channels of the louvered separators of the secondary steam, while maintaining a large supersaturation of the brine ΔC _n , mEq / L during its stepwise evaporation. In particular, during the evaporation process, the concentration of dissolved hardness salts in the feed water of the first evaporation stage increases (line a-b). In this case, due to scale formation in the bypass channels and openings of the switchgear (line bc), the brine enters the evaporation chamber of the second stage of evaporation with a concentration of dissolved hardness salts corresponding to the point ″ c ″. Similar processes occur in subsequent evaporation stages operating under conditions of stepwise pressure reduction (stepwise broken line 1). Unevaporated brine is removed from the desalination tank at a concentration of hardness salts C ₃ , mEq / l from the brine receiver of the fifth evaporation stage by a pumping brine pump.

Unlike the one known in the proposed OS, the input of the evaporation chamber of the first stage of the evaporator receives softened feed water with suspended sludge from the feed water receiver 77 with a reduced concentration of dissolved salts of hardness C ₂ , mEq / l through throttling and spray pipes connected to it 13 devices of this evaporation stage, where it evaporates due to the heat of superheat in a vacuum mode at a saturation temperature T ₂ , ° C (Fig. 8). Unevaporated brine with particles of sludge from the brine receiver 12 of the first stage of evaporation, through the bypass pipes 13 of the throttle-spray devices of the second stage of evaporation connected to it, enters the vacuum chamber of the second stage of evaporation. The transfer of the unevaporated brine with suspended sludge to the subsequent evaporation stages is carried out similarly from the brine receiver 12 of the previous evaporation stage through the bypass pipes 13 of the throttle-spray devices of the corresponding evaporation stage connected to them.

Moreover, due to the presence of suspended sludge particles in the volume of the supersaturated brine contained in the cavities of the bottom zone and the brine receivers of the desalination stage of desalination, in each of them a significant decrease in the supersaturation of the liquid (line 2) is _{achieved by} ΔC _nt , mEq / l (here the index ″ N ″ corresponds to the number of the evaporation stage) due to volumetric sludge formation in the brine, which determines the decrease in the rate of scale formation on the surfaces of the working channels of the secondary steam louver separators, due to the reduction in radio hardness salts in the brine droplets introduced them together with the flow of the separated vapor, which is essential for solving the technical problem of improving the reliability of the work op.

In addition, due to a significant excess of the total surface of the slurry particles contained in the feed water of the first evaporation stage and the brine of the subsequent evaporation stages, the process is distracted relative to the total surface of the natural crystallization centers on the working surfaces of the bypass channels and openings of the throttle-spray device (ДРУ) scale formation from their rough surface to sludge particles suspended in the volume of the transported solution, i.e. surface scale formation is replaced by intensive sludge formation in the volume of the transported liquid. In this case, an additional factor in reducing the scale formation rate in the desalination elements mentioned is the very decrease in the concentration of scale forming salts in the feed water at the inlet of the five-stage adiabatic evaporator, as well as in the volume of brine in the evaporation stages.

Coarse sludge particles are removed together with brine from the brine receiver 12 of the fifth evaporation stage by a pumping brine pump 50 overboard at a temperature of t ₃ = 42 ° C with a concentration of C ₄ , mEq / l.

From the above comparison of the physical processes occurring in the known and proposed OS, the positive effect is obvious, achieved by pre-softening the feed water in a two-section feed water receiver, using the volume of the feed water receiver of the first evaporation stage as an additional section of thermal softening at the inlet of the multi-stage adiabatic evaporator . In particular, the physical processes in the evaporation stages of the five-stage adiabatic evaporator of the proposed OS occur at a lower concentration of scale-forming salts in the brine, which leads to a decrease in the rate of scale formation in the bypass channels of the switchgear and on the working surfaces of the channels of the louvered separators of the secondary pair of evaporation stages, which is the achieved effect in the implementation target task of the general inventive concept.

A distinctive feature and the effect achieved by the claimed group of inventions both as a whole and its additional parts is the use of a single thermophysical process ″ heating ″, which is fundamental in the thermal distillation desalination of sea water, as well as in the use of a single aqueous medium for generation ″ seed ″ sludge particles used in the future for thermal softening of feed water at the inlet to the evaporator and brine in its evaporation stages, which, identifying awn chemical composition of the chemical composition of the slurry particles soften solution predetermines a lower crystallization operation in these "seeding" of sludge particles in the volume of the supersaturated solution, i.e., It is a catalytic factor for effective sludge formation (increase in the size of sludge particles) in the solution volume, accompanied by a decrease in its supersaturation with hardness salts in the course of its movement in the OS elements.

It is also important that the mode of partial recirculation of the purged brine through a jumper with a valve 51, built into the suction pipe of the feed pump, used in the well-known OS for maintaining the calculated temperature of the cooling water at the inlet of the secondary steam condenser 5 of the fifth stage of evaporation of the evaporator in a ship sailing in cold water, here it can be recommended for use when operating the op-amp as a constant mode of partial recirculation of the purged brine containing particles suspended sludge, to reduce the rate of scale formation on the internal heat transfer surfaces of the pipes, along the entire path of successive passage of heated seawater in the cooling pipes of the secondary steam condensers, a two-stage steam jet ejector condenser and a multi-pass shell-and-tube steam feed water heater, achieved by diverting the crystallization of hardness salts from them working surfaces on the particles of the moving sludge introduced by the recirculating brine into the volume moving oh sea water, ie, by replacing surface scale formation with bulk sludge formation. This will bring an additional positive effect.

At the same time, the restrictive condition for using such partial recirculation is the permissible excess of the calculated temperature of the cooling water at the inlet of the secondary steam condenser of the last stage of evaporation of the evaporator, which ensures an acceptable decrease in the operational performance of the proposed desalination plant.

Thus, the proposed technical solutions for the structural layout of the heat softener and two-section feed water receiver and circuit solutions for their inclusion in the desalination plant allow us to sufficiently realize the task in the implementation of the inventive concept to improve the reliability of the multi-stage adiabatic desalination plant, namely: reducing the speed scale formation on the working surfaces of interstage bypass pipes and throttle-spray devices stem, and also on the surfaces of the channels of the secondary steam louver separators, which is achieved by efficiently generating primary “seed” sludge particles suspended in an aqueous medium in a thermal softener and then using them as crystallization centers to reduce feed water supersaturation in the volumes of a two-section feed water receiver and receiver feed water of the first stage of evaporation, as well as brine contained in the bottom zone of the evaporation chambers, the cavities of the brine receivers and connected to them epusknyh tubes throttling spray devices with sequential passing the solution was evaporated in the evaporation stages.

In addition, it is possible to reduce the rate of scale formation on the heat transfer surfaces of secondary steam condensers, a two-stage steam-jet ejector condenser and an external multi-pass steam feed water heater during the operation of the op-amp in the mode of partial brine recirculation containing suspended sludge particles due to distraction of crystallization of scale-forming salts from heat transfer salts surfaces on these particles of sludge, i.e. replacing surface scale formation with bulk sludge formation along the entire path of sequential heating of feed water.

Moreover, due to the use of a single thermophysical process (heating) and a single aqueous medium during the implementation of distillation desalination of sea water and the generation of mobile sludge, the need to use additional technological materials is eliminated and technical conditions are created for the complete automation of the claimed desalination plant using uniform automation means.

It should be noted that the sludge that is removed together with the brine in its composition (CaCO ₃ , Mg (OH) ₂ , CaSO ₄ ) is inert and harmless to the environment, i.e. the technological processes used to solve the technical problem are environmentally friendly, which is extremely important in conditions of tightening the requirements for environmental safety of the technologies used.

Claims (2)

1. Desalination plant, including an external multi-pass shell-and-tube steam feed water heater, having a straight-tube bundle with a dividing wall forming a vapor-air cavity for collecting and subsequent removal of non-condensed vapor-air mixture, and also equipped with a condensate collector with its level sensor; two-stage steam jet ejector; a condenser of a two-stage steam-jet ejector with separate condensation chambers of the air-vapor mixture, respectively, from the ejectors of the first and second stages, which together with the cooling water pipes are connected in series therein, condenser coolers with their condensate collectors communicated with each other by a U-shaped pipe, as well as equipped with separate branch pipes air from these condensation chambers; as well as containing pumps, pipelines, disconnecting and switching automatic valves, instrumentation, automatic control and protection means; a multistage adiabatic evaporator mounted in a sealed enclosure made in the form of a rectangular parallelepiped and containing vertical separation walls forming separate evaporation stages, in each of which a two-way shell-and-tube secondary vapor condenser is installed horizontally in the upper zone, having a straight-tube bundle with a separation partition forming a cavity for collection and subsequent removal of non-condensing vapor-air mixture, as well as distill equipped with a collector yat, and in the middle zone a louvre type secondary steam separator is mounted, separating the data of the evaporation stage into the upper zone, which is condenser, and the lower, which is evaporative, while in the lower zone of each evaporation stage there is a brine receiver of this evaporation stage, made in the form of a drain pipe increased diameter with the bypass pipes of the throttle-spray device connected to the subsequent stage of evaporation of the evaporator, each of these bypass pipes contains in its upper free part inside this throttling device, over the upper edge of each of which is disposed a mushroom bump stop performing the function of the reflectors "fountain" water jets emanating from the holes of the throttle device; all data of the evaporation stage are successively communicated to each other by connecting bypass pipes of the cooling water of the secondary steam condensers and are equipped with pipes of successive bypass of the resulting vapor-air mixture from the respective cavities of these secondary vapor condensers in the direction from the first evaporation stage to the last, and two adjacent chambers of the evaporation stages are in series connected between in the lower zone bypass pipes from the brine receivers of a given evaporation stage to the throttle evacuation devices of the subsequent evaporation stage, while the brine receiver of the last evaporation stage is in communication with a pumping brine pump, the pressure pipe of which has a branch jumper with a valve integrated in the pipe in front of the evaporator feed pump, the pressure cavity of which is connected to the receiving pipe of the cooling pipes of the secondary stage condenser of the last stage evaporation, moreover, the pressure pipe of the feed pump is equipped with a flow meter, and built into its suction pipe n filter the seawater; the multistage adiabatic evaporator also contains a system of interstage throttle washers mounted on the mentioned pipes of the sequential bypass of the vapor-air mixture from the secondary vapor condensers, while the vapor-air cavity of the secondary vapor condenser of the last evaporation stage is in communication with the receiving cavity of the mixing chamber of the first-stage steam-jet ejector, the outlet and diffuser part of which vapor-air cavity of the condensation chamber of the condenser of the first stage of the steam-jet ejector, strips the mixing chamber of the second-stage steam-jet ejector is connected to the pipe for exhausting air from the condensation chamber of the condenser of the first stage of the steam-jet ejector, the output diffuser of the second-stage steam-jet ejector is connected to the vapor-air cavity of the condenser condensing chamber of the second-stage steam-jet ejector equipped with an air outlet; the inlet nozzle part of both of these ejectors is connected in parallel to the working steam supply pipe, and the condensate chamber of the condenser chamber of the condenser of the first stage of the steam-jet ejector is in communication with the condensate chamber of the external multi-pass shell-and-tube steam feed water heater; to the receiving part of the cooling pipes of the condenser chamber of the condenser of the second stage of the steam jet ejector, a discharge pipe of the cooling water of the condenser of the second steam of the first stage of evaporation of the evaporator is connected, and the output of the cooling pipes of the condensation chamber of the condenser of the first stage of the steam jet ejector is connected to the receiving part of the aqueous cavity of the external multi-pass shell-and-tube steam heater whose vapor cavity is also connected to a low-grade source of heating steam and through a steam line with a built-in temperature controller, and the heater is made with the cross direction of movement of their mutually heat-exchanging media with a rectilinear direction of movement of the heated stream, the output of this water cavity of the external multi-pass shell-and-tube steam feed water heater, in turn, by means of a discharge pipe equipped with a temperature sensor connected by a control pulse to a temperature controller integrated in the supply steam RA has a communication with the inlet pipe of the feedwater receiver of the first stage of evaporation of the evaporator, built-in along the axis of its elliptical bottom, and the bypass pipes of the throttle-distribution devices of the first stage of evaporation of the evaporator are connected to the outlet of this feedwater receiver; distillate collectors of all secondary vapor condensers are pairwise connected in series with each other by interstage distillate bypass pipes, each of which is made in the form of a U-shaped pipe, while the distillate collector of the condenser of the second pair of the last evaporation stage is connected to the receiving pipe of the distillate tank connected by a pipe to the pumping distillate pump ; the air cavity of the distillate tank is in communication with the vapor-air cavity of the secondary steam condenser of the last stage of evaporation of the evaporator to equalize the pressure in these cavities and the reliable flow of the distillate, and the distillate tank is equipped with a level sensor communicated by a control pulse with a tank level regulator built into the pressure part of the pipeline of this pump for maintaining its working level and stable operation of the pumping distillate pump, and at the outlet section of the pressure pipe Chiva distillate pump set flow meter and automatic three-way solenoid switching valve, switching the conduit to discharge the distillate at its low quality by means of its communication with the control pulse solenomerom mounted on the measuring bridge branch circuit distillate; the steam-air mixture from the steam-air cavity of the external multi-way shell-and-tube steam feed water heater is diverted by means of a pipeline to the steam-air cavity of the secondary steam condenser of the first stage of evaporation of the evaporator, and the heating condensate from the condensate collector of this external multi-way shell-and-tube steam feed water heater is diverted to the pipeline by the piping for its reuse in the vapor condensate cycle, at his condensate collector is equipped with a level sensor communicated by a control pulse with a level regulator installed on the discharge pipe of the condensate drain pump to maintain the working level in the condensate collector and stable operation of the pump itself, and an automatic three-way switching solenoid valve is installed on the output section of its pressure pipe, switching the given pipeline to condensate discharge with its low quality by means of its connection with a control pulse to a salt meter m installed on the measuring branch jumper of the condensate circuit, characterized in that it further comprises a two-section receiver for feed water with nozzles for supplying and discharging aqueous media, installed in front of the receiver for feed water for the first stage of evaporation of the evaporator, and a thermal softener containing nozzles for supplying and discharging working fluids, while its branch pipe for supplying an aqueous medium is in communication with a branch having a control valve, a flow meter and a level regulator, and this branch itself is built into the outlet pipe oprovod water outlet portion of the cavity of the outer tube bundle of the steam heater changeover feedwater; the outlet pipe of the aqueous medium with the suspended slurry of the thermal softener is in communication with the inlet pipe of the two-section feed water receiver, and its pipe of the outlet of the vapor-air medium is communicated with the vapor-air cavity of the external multi-pass shell-and-tube steam feed water heater; the steam inlet of the thermo softener is connected to a source of heating steam for additional heating of the aqueous medium in it, and the two-section feed water receiver contains a cylindrical body with an elliptical cover and bottom, water inlet and outlet pipes, pipes for connecting a water indicating column in its upper part and is equipped with a sensor level installed in the upper part of the cylindrical body, and also has an additional shell inside the body, built along the axis of its elliptical bottom with a length of height from the bottom, equal to the height of the cylindrical part of the body , and forming two vertical open cavities: external and central; the external cavity with a branch pipe located in its lower zone is in communication with the pipe for supplying the aqueous medium of the feedwater receiver of the first evaporation stage of the evaporator, and the central cavity with the supply pipe placed along the bottom axis is connected to the outlet pipe of the outlet part of the water cavity of the external multi-pass shell-and-tube steam heater water containing a control valve and a level controller communicated by a control pulse with a level sensor of a two-section receiver of feed water, p When in use, its central cavity in the bottom zone and communicates with a water supply pipe with suspended sludge from termoumyagchitelya for their qualitative mixing with feed water; along the axis of the elliptical cover, an air exhaust pipe is integrated, connected to the pipeline with an air valve. 2. A heat softener comprising a vertical cylindrical body with a bottom, a cover and a steam inlet pipe, as well as steam discharge pipes, softened water and sludge, as well as a water supply manifold with distributing nozzles, under which the receiving contact-film water heaters arranged in a horizontal partition are placed confuser type; and also containing two vertical cylindrical shells mounted concentrically on the bottom of the housing along its axis and forming three vertical open cavities, of which the outer cavity is formed by the inner surface of the shell and the peripheral shell, the middle cavity is formed by the peripheral shell and the central shell, and the central shell itself forms a central cavity, characterized in that it further comprises a perforated diaphragm integrated in the housing under its cover, having openings in iferiynoy zone to arrange a uniform supply of water vapor in the heating zone; a domed horizontal partition installed with an annular gap relative to the inner wall of the housing on the supporting elements on these walls and located below the horizontal partition with the receiving contact-film contact-type water heaters of the confuser type; and also further comprises a vapor recovery manifold mounted under a domed partition; the upper end of the peripheral shell is located above the upper end of the Central shell, and the length of both of them in height from the bottom is more than half the height of the casing of the softener; in the lower part of the peripheral shell along its perimeter, cutouts are made for the flow of fluid from the external cavity to the middle; the shape of the bottom of the casing and its cover is made elliptical, the water outlet pipe is combined with the discharge of sludge particles and mounted along the axis of the elliptical bottom of the body under its central cavity, and the steam supply pipe is mounted in the elliptical cover of the body along its axis; while the cylindrical body, in its upper part, is equipped with nozzles for connecting a water-indicating column, and is also equipped with a level sensor; moreover, the level sensor is installed in the upper part of the cylindrical casing and is connected by a control pulse to a level regulator installed on the branch pipe of the outlet part of the water cavity of the external multi-pass shell-and-tube steam feed water heater, which is connected to the water supply pipe of the thermal softener, and the collectors of the outlet of the vapor and water supply connected to contact-film water heaters, vertical cylindrical shells and a domed horizontal partition made Heat resistant hydrophobic food grade plastics.

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