JP4185451B2 - Seawater desalination equipment - Google Patents

Description

  The present invention relates to a seawater desalination apparatus that desalinates seawater using an evaporation method, and more particularly to a seawater desalination apparatus that can efficiently desalinate using exhaust heat.

  There are various types of seawater desalination methods for obtaining fresh water from seawater, such as evaporation, reverse osmosis, freezing, pervaporation, and electrodialysis. In an environment where a heat source that raises the temperature of seawater can be easily obtained, multistage flash evaporation type seawater desalination is performed in which the heated seawater is evaporated in a decompression space and the resulting water vapor is condensed to obtain fresh water in multiple stages. Many devices have been used in the past. In addition, with the same evaporation / condensation process, spraying seawater into the decompression space makes it easier for water to evaporate, and even if the temperature difference between the seawater to be evaporated and the cooling water in the condensing part is small, it becomes desalinated. A spray flash type seawater desalination apparatus that can be used is also used, and an example of such an apparatus is described in Japanese Patent No. 2878296, which is shown in FIG. FIG. 4 is a schematic block diagram of a conventional seawater desalination apparatus.

  In the conventional seawater desalination apparatus 100 shown in FIG. 4, the seawater to be evaporated is taken from near the sea surface where the temperature is relatively high, and this is led to the flash chamber 101 in a decompressed state and sprayed from the nozzle at a low temperature. Evaporate moisture. Then, the evaporated water is once passed through the separator 102 to separate the mist, and then led to the condensers 103 and 104 cooled by relatively low temperature seawater taken from the deep sea to condense the water to obtain fresh water. Yes.

  Thus, in the conventional seawater desalination apparatus 100, seawater desalination can be performed at low cost by suppressing energy consumption by desalinating seawater using only the temperature difference between the surface and deep seawater. In recent years, however, in order to further increase efficiency, the seawater to be evaporated is heated using waste heat that was normally discarded at power plants, etc. A desalination device has been proposed to increase the amount of freshwater condensed (freshwater yield), and in particular, heat recovery is performed using seawater as the cooling water for the condenser of the LNG thermal power plant to increase the seawater temperature. An example of a seawater desalination apparatus that leads to a vacuum space for evaporation is disclosed in Japanese Patent Laid-Open No. 9-52082.

In recent years, not only such spray flash type but also an evaporative seawater desalination apparatus and a method for recovering exhaust heat such as a power generation apparatus using a steam power plant or an internal combustion engine have been widely used. In these cases, seawater is used as a cooling medium for the condenser and heat exchanger, and the temperature of the seawater is raised while lowering the temperature of the working fluid.
Japanese Patent No. 2878296 JP-A-9-52082

  The conventional seawater desalination apparatus is configured as described above, and part of the seawater evaporates when the seawater is introduced into the decompression space. It was discharged and left in the sea. However, when the seawater before evaporation is heated by exhaust heat recovery, etc., the seawater is accompanied by a temperature drop due to evaporation, but the remaining seawater that has not evaporated remains at a sufficiently high temperature even when leaving the device. The temperature is 5 ° C higher than the temperature of seawater in the sea, and it is wasteful that the heat of seawater is thrown into the sea as waste heat, and the adverse effect of warm seawater on the surrounding environment cannot be ignored. Had problems.

  On the other hand, thermal energy corresponding to the temperature difference between seawater discharged from such conventional seawater desalination equipment and seawater in the sea may be recovered and used appropriately using an efficient heat recovery system, Effective use is required from the viewpoint of energy saving. In addition, in terms of seawater desalination, further increase in yield per unit is required, and a mechanism for increasing the yield of fresh water by increasing the efficiency of evaporation and condensation is strongly demanded.

  The present invention has been made to solve the above-mentioned problems, and by adding a desalination facility to the heat dissipating means for discharging after discharging heat to the introduced seawater, the heat is recovered and the yield of fresh water is efficiently secured. Another object of the present invention is to provide a seawater desalination apparatus that can reduce the environmental load on the sea caused by discharged seawater.

The seawater desalination apparatus according to the present invention is a seawater desalination apparatus provided with predetermined heat radiating means that releases heat to seawater taken in as a medium for heat exchange and discharges the seawater at a high temperature. A spray flash type flash evaporator that discharges the remaining seawater that has not evaporated, while spraying the seawater into a container that has been depressurized to a predetermined pressure below atmospheric pressure to partially evaporate seawater. A condenser that is used as cooling water and cools and condenses the water vapor obtained in the flash evaporator to obtain water that does not contain salt, and a plurality of the condensers are arranged in parallel. Each of the heat transfer parts made of a thin plate is divided into a predetermined set of two of two sets of substantially parallel two ends obtained by grouping two sets of two ends that are substantially parallel to the four sides of a substantially rectangular shape. Adjacent one heat transfer section and watertight at the edge While welding, the other heat transfer parts adjacent to each other and the two sets of two end sides different from the predetermined set of two end sides are welded to each other in a watertight manner, and are integrated together between the heat transfer parts. Each of the first flow path through which the water vapor obtained by the flash evaporator passes and the second flow path through which the sea water as the cooling water passes are formed, and the water vapor passing through each of the first flow paths and each of the second flow paths. The seawater passing through the flow path is a heat exchange unit that forms a cross flow, and each first flow path of the condenser is divided into three flow path groups with two predetermined heat transfer sections as boundaries. The two flow path groups in the first section are each a main condensing part that directly flows the water vapor obtained in the evaporator, while the central flow path group once passes through the main condensing part and then the uncondensed steam. is an auxiliary condenser unit for flowing, to said radiation means, as the cooling water in the condenser While supplying the use seawater as the heat exchange medium is intended to introduce the seawater discharged from the heat dissipating means in the flash evaporator.

As described above, in the present invention, spray flash type seawater desalination means is added to the seawater introduction and discharge portion in the predetermined heat radiation means, and the flash is made using the temperature difference of seawater generated during use in the heat radiation means. By increasing the temperature of the seawater introduced into the evaporator and obtaining a state where evaporation in the flash evaporator is likely to occur, seawater can be efficiently desalinated, and the seawater is guided to each device and the pressure in the vacuum vessel is reduced. Energy consumption related to evaporation / condensation other than pump power can be suppressed, and fresh water can be obtained at low cost. Furthermore, the temperature of the used seawater discharged to the sea can be lowered by recovering the exhaust heat corresponding to the temperature difference that has been thrown away outside the heat radiating means with the desalination of seawater. Adverse effects can be suppressed.
Furthermore, using a heat exchange unit that performs indirect heat exchange between steam and seawater that form a cross flow through a substantially plate-like heat transfer section arranged in parallel as a condenser, the flow path that condenses through the steam is the main condensing section. Divided into auxiliary condensing sections, uncondensed water vapor that has passed through the flow path group that is the main condensing section among the flow paths between the heat transfer sections is passed through the flow path group that is the auxiliary condensing section, and the opportunity for condensation on the water vapor is provided. By setting twice, it is possible to condense more efficiently with one condenser, it is not necessary to separately arrange an auxiliary condenser etc. on the rear stage side of the condenser, piping equipment etc. can be omitted, Cost reduction of equipment related to the condensation process can be achieved.

  Further, in the seawater desalination apparatus according to the present invention, if necessary, the heat radiating means introduces seawater heated by a predetermined heater into a casing whose pressure is reduced to a predetermined pressure equal to or lower than atmospheric pressure to evaporate water. A multistage flash evaporation type seawater desalination apparatus that cools and condenses water vapor generated by the evaporation in a condensing unit that uses seawater introduced from the outside as at least a part of cooling water, and obtains fresh water, Seawater that has been used as cooling water in the condensing unit is heated by the heater and introduced into the casing, and seawater discharged from the casing to the outside is introduced from the new seawater introduced into the condensing unit Is at least 5 ° C. or higher.

  Thus, in the present invention, the heat dissipating means is another seawater desalination apparatus, and the seawater desalination apparatus can perform new seawater desalination without affecting the operation of the other seawater desalination apparatus. The yield of fresh water can be efficiently increased in combination with the amount of water produced in Japan, and a new desalination device can be installed in the form of taking water into the existing seawater desalination device and interrupting the drainage pipe. Therefore, it is possible to reduce the cost required for the construction compared to the case where a seawater desalination apparatus is simply added, and the cost for obtaining fresh water can be reduced.

  In the seawater desalination apparatus according to the present invention, if necessary, the heat dissipating means causes the exhaust heat retained fluid exhausted from a predetermined exhaust heat source to exchange heat with each other using seawater as a cooling medium. It is a heat exchanger for exhaust heat recovery that lowers the temperature of the retained fluid while raising the temperature of the seawater by at least 5 ° C. or more before the heat exchange.

  As described above, in the present invention, the heat exchanger that releases heat from the waste heat holding fluid to the seawater is used as the heat radiating means, and the seawater desalination can be performed without affecting the operation of the heat exchanger. Can be installed efficiently, and a desalination device can be installed in the form of interrupting the intake and drainage pipes of existing heat exchangers, eliminating the need for new intake and drainage work for the sea, and simply desalinating the seawater. Compared to the construction of a new plant, the construction cost can be reduced and the cost of obtaining fresh water can be reduced.

  Further, in the seawater desalination apparatus according to the present invention, if necessary, the flash evaporator is provided with an injection unit for injecting seawater in a substantially mist-like manner in the lower part in the decompression vessel with the injection direction facing upward. The seawater is blown upward.

  In this way, in the present invention, the injection unit is disposed in the lower part of the decompressed container, and the seawater injected from the injection unit rises from the lower part by injecting seawater upward from the injection unit to cause flash evaporation. However, it is possible to secure the maximum stroke that can be dispersed as liquid droplets in the container until it eventually descends and falls to the bottom of the container, and increases the period during which the phase change from liquid particles to water vapor can occur during flash evaporation in the vacuum container. As a result, the amount of water vapor obtained can be increased, and the yield of condensed water in the condenser can be increased.

  Further, in the seawater desalination apparatus according to the present invention, if necessary, the condenser is disposed near the center in the decompressed container of the flash evaporator, and the evaporated water vapor is disposed at the main condensing portions on both ends from the upper side. A structure in which uncondensed water vapor that has passed through the main condensing part and reaches the lower side is further introduced into the central auxiliary condensing part, and the non-condensable gas is discharged from the upper side of the auxiliary condensing part directly to the outside of the container. It is supposed to be.

  As described above, in the present invention, the condenser is accommodated in the decompression container of the flash evaporator, and the evaporator and the condenser are integrally disposed, and the vapor obtained by the evaporator can enter the condenser as it is. As a result, it is easy to maintain the decompressed pressure, and it is possible to reliably condense the vapor by reaching the condenser in the gas phase, allowing a series of processes from evaporation to condensation to proceed smoothly in the decompression vessel. The overall efficiency of the apparatus can be increased, and the exhaust from the decompression vessel can be led to the decompression exhaust apparatus as it is, and the entire apparatus can be reduced in cost with a simple and compact structure.

(First embodiment of the present invention)
Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration explanatory diagram of a seawater desalination apparatus according to the present embodiment.
In FIG. 1, a seawater desalination apparatus 1 according to the present embodiment includes a flash evaporator 10 that flashes and evaporates seawater in a decompression space to obtain water vapor, and condenses the water vapor obtained by the flash evaporator 10 to salinize. A condenser 15 for obtaining water that does not contain water, and a plurality of pipes and pumps for introducing seawater into the flash evaporator 10 and discharging fresh water or seawater from the condenser 15, respectively. It is the structure arrange | positioned combining with the main desalination apparatus 50 as another seawater desalination apparatus.

  The flash evaporator 10 includes a decompression container 11 whose interior space is decompressed to an atmospheric pressure, a nozzle 12 for spraying seawater disposed in the decompression container 11, and a steam flow toward the condenser 15. It is a structure provided with the separator 13 which capture | acquires and removes the fine water droplet (mist) of the mixed seawater. The inside of the decompression vessel 11 is decompressed by the decompression exhaust device 17 to a pressure equal to or lower than the saturated vapor pressure of water at the same temperature as the seawater ejected from the nozzle 12, and part of the seawater ejected in the decompression vessel 11 is It is a mechanism in which the seawater temperature of the remaining liquid phase decreases while changing from the liquid phase to the gas phase. The nozzle 12 jets seawater guided from the outside into the interior space of the decompression vessel 11 in the form of a mist.

  In this flash evaporator 10, the unevaporated seawater from the main desalination device 50 is guided from the drain pipe 54 of the main desalination device 50 to the nozzle 12 in the decompression vessel 11 via the vacuum degassing device 14. Injected into the internal space of the decompression vessel 11. The amount of seawater that has not evaporated in the decompression vessel 11 is discharged out of the decompression vessel 11, returns to the drain pipe 54, and is discharged to the sea through this. As described above, the conduit for sending the seawater to be evaporated to the flash evaporator 10 and the conduit for discharging the unevaporated seawater from the flash evaporator 10 are each a drain pipe of the main desalination apparatus 50. 54 is arranged so as to interrupt in the middle of 54, and it is not necessary to provide a pipe line and a discharge port for discharging directly from the flash evaporator 10 to the sea.

  The condenser 15 is provided with a heat transfer section 16 through which cooling water passes in an interior communicating with the decompression vessel 11 of the flash evaporator 10, and the introduced steam is brought into contact with the heat transfer section 16 to cool the cooling water. This is a well-known configuration in which the condensed water obtained by heat exchange with the water is collected and sent to the outside, and detailed description thereof is omitted. As the cooling water, seawater before being used in the main desalination apparatus 50 is used. This seawater is taken from the intake pipe 53 of the main desalination apparatus 50 and introduced into the heat transfer section 16, and then outside the apparatus. It is discharged and reaches the remaining portion of the water intake pipe 53 and goes to the main desalination apparatus 50. As described above, the pipe that guides the seawater as the cooling water to the condenser 15 and the pipe that discharges the seawater from the condenser 15 are respectively inserted into the intake pipe 53 of the main desalination apparatus 50. It is not necessary to provide a water intake and a pipe that are directly installed from the sea.

  A vacuum exhaust device 17 is connected to the condenser 15 through a pipe line to decompress the inside of the condenser 15 and the decompression vessel 11 of the flash evaporator 10 that communicates with the water in the decompression vessel 11. The temperature at which the vapor changes from the vapor phase to the vapor phase and the temperature at which the vapor changes from the vapor phase to the liquid phase (condenses) in the condenser 15 is maintained to be lower than the respective temperatures at atmospheric pressure. In addition, a tank 18 is also provided that is attached to the condenser 15 and temporarily stores fresh water obtained as condensed water.

  The main desalination apparatus 50 includes a casing 51 that is divided into a plurality of compartments and is in a predetermined reduced pressure state, and a condensing unit 52 that is disposed above the casing 51 and allows seawater to pass therethrough. It is a well-known multi-stage flash evaporation type seawater desalination device that condenses water vapor generated by evaporating seawater introduced into each section of the casing 51 in the condensing unit 52 to obtain fresh water, and detailed description thereof is omitted. . The seawater desalination apparatus 1 is interposed between the intake pipe 53 and the drain pipe 54 of the main desalination apparatus 50. In addition, as a seawater heater before the introduction of the casing 51 in the main desalination apparatus 50, a condenser 60 of a steam power plant is used, and between the seawater used as cooling water for the condenser 60 and a high-temperature working fluid. This is a mechanism to exchange heat.

  Next, the operation of the seawater desalination apparatus according to the present embodiment will be described. First, seawater taken from the sea is introduced into the condenser 15 as cooling water through the first half of the intake pipe 53 of the main desalination apparatus 50, and heat exchange with the steam around the condenser 15 cools this steam. Instead of condensing, the temperature rises, and in this high temperature state, the condenser 15 exits and proceeds to the latter half of the intake pipe 53 and is led to the condensing unit 52 of the main desalination apparatus 50. In the condensing part 52, the temperature is increased by exchanging heat with the steam that has been used as cooling water again and reaches the periphery of the condensing part 52 in the decompressed casing 51. Seawater discharged from the final stage of the condensing unit 52 is guided to a condenser 60 of a steam power plant as a heater, used as cooling water, and warmed to a high temperature by heat exchange with a high-temperature working fluid.

  The seawater thus warmed by the condenser 60 is introduced into the decompressed casing 51 of the main desalination apparatus 50, and while flowing down between the sections, a part of the water is evaporated and the temperature is lowered. To go. The evaporated vapor is cooled by the upper condensing part 52 and condensed to form water droplets that do not contain salt, and these are collected to obtain fresh water. In the main desalination apparatus 50, the temperature of the cooling water (seawater) at the inlet of the condensing unit 52 rises as compared with the case where seawater is directly introduced from the sea. Since the temperature is rising, there is almost no decrease in the condensation performance.

  On the other hand, seawater that has not evaporated in the casing 51 is discharged from the casing 51 to the drain pipe 54. The seawater at the time of being discharged into the drain pipe 54 is at a temperature higher by about 5 ° C. than when it was introduced into the main desalination apparatus 50, and this seawater is led to the flash evaporator 10 for further desalination. Plan.

  Seawater that has come out of the main desalination apparatus 50 is once led to the vacuum degassing apparatus 14 from the first half of the drain pipe 54, and the air in the seawater is removed. Subsequently, the seawater is guided to the decompression vessel 11 of the flash evaporator 10, and the seawater is sprayed from a number of nozzles 12 disposed in the decompression vessel 11. In the inner space of the decompression vessel 11 where the pressure is reduced to about 10 to 60 mmHg, a part of the injected seawater changes into vapor by flash evaporation, and the temperature of the seawater decreases at the same time. In the decompression vessel 11, seawater is jetted upward from the nozzle 12 to form fine water droplets, and the surface area facing the inner space of the vessel has increased remarkably. Since the stroke is lengthened, water in seawater can be efficiently evaporated.

  The vapor obtained by the evaporation of moisture passes through the separator 13 and flows into the condenser 15 with the floating liquid (mist) removed. In the condenser 15, the steam is cooled by exchanging heat with seawater having a low temperature immediately after taking water through the heat transfer section 16, condensed on the surface of the heat transfer section 16 to form salt-free water droplets, and once below the condenser 15. After being collected, it is collected in the tank 18 and sent out as a collective amount of fresh water.

  On the other hand, the seawater that has not evaporated in the flash evaporator 10 accumulates in the lower part of the decompression vessel 11 and is finally discharged out of the decompression vessel 11 and discarded into the sea through the latter half of the drain pipe 54. Since the temperature difference between the discarded seawater and the seawater originally in the sea is sufficiently small due to the heat consumption accompanying desalination, the adverse effects on the surrounding environment due to the discharge are small.

  As described above, in the seawater desalination apparatus according to the present embodiment, the spray flash type seawater desalination apparatus 1 is added to the seawater introduction and discharge portion of the main desalination apparatus 50, and the use in the main desalination apparatus 50 is performed. The temperature difference between seawater generated during the period is increased, the seawater temperature introduced into the flash evaporator 10 is increased, and a state in which evaporation in the flash evaporator 10 is likely to occur is obtained. In addition, energy consumption related to evaporation / condensation other than pump power for guiding seawater to each device or reducing the pressure in the decompression vessel 11 can be suppressed, and the yield of fresh water can be increased at low cost. Moreover, the temperature of the used seawater discharged | emitted to the sea can be lowered | hung by heat-recovering the waste heat corresponding to the said temperature difference thrown away outside the main desalination apparatus 50 with seawater desalination, Reduces the negative impact on the environment. Furthermore, a new device can be arranged in the form of interrupting the intake pipe 53 and the drain pipe 54 of the existing main desalination apparatus 50, so that no new intake / drainage work for the sea is required, and the seawater desalination apparatus is simply provided. Compared with the case of adding more, the cost for construction can be reduced, and the cost for obtaining fresh water can be reduced.

  In the seawater desalination apparatus according to the embodiment, the condenser 15 that condenses the vapor in communication with the decompression vessel 11 of the flash evaporator 10 is arranged in one stage. A small auxiliary condenser may be provided on the rear stage side to reliably condense uncondensed water vapor flowing toward the decompression exhaust device 17 to reduce the load on the decompression exhaust device 17 and to obtain fresh water. Yield can be increased.

  In addition, in the seawater desalination apparatus according to the above embodiment, the seawater discharged from the main desalination apparatus 50 is once guided to the decompression deaeration apparatus 14 before being introduced into the decompression vessel 11 of the flash evaporator 10, Although it is set as the structure which removes air, it is not restricted to this, It can also be set as the structure which introduce | transduces seawater directly to the pressure reduction container 11 of the flash evaporator 10, without going through the pressure reduction deaeration apparatus from the main desalination apparatus 50.

(Second embodiment of the present invention)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram of a flash evaporator and a condenser in the seawater desalination apparatus according to the present embodiment, and FIG. 3 is a schematic perspective view of a main part of the condenser in the seawater desalination apparatus according to the present embodiment. is there.

  In each of the drawings, the seawater desalination apparatus according to the present embodiment is similar to the first embodiment, and includes a flash evaporator 20, a condenser 24, and a plurality of units disposed in combination with the main desalination apparatus 50. The difference is that the flash evaporator 20 and the condenser 24 are integrally disposed in one decompression vessel 21.

  The flash evaporator 20 includes a decompression container 21 whose interior space is decompressed to an atmospheric pressure, a nozzle 22 for spraying seawater disposed in the decompression container 21, and a steam flow toward the condenser 24. A separator 23 that captures and removes fine water droplets (mist) of mixed seawater, and a condenser 24 is integrally disposed in the decompression vessel 21. In the flash evaporator 20, as in the first embodiment, the unevaporated seawater from the main desalination apparatus 50 is guided to the nozzle 22 in the lower part of the container, and forms a mist upward into the internal space of the decompression container 21. It is a mechanism that is sprayed on. The inside of the decompression vessel 21 is decompressed by a decompression exhaust device (not shown) to a pressure equal to or lower than the saturated vapor pressure of water at the same temperature as the seawater ejected from the nozzle 22. The amount of seawater that has not evaporated in the decompression vessel 21 is discharged out of the decompression vessel 21, returns to the drain pipe 54, and is discharged to the sea through this.

The condenser 24 includes a plurality of heat transfer portions 25 made of a substantially rectangular thin metal plate in a plurality of juxtaposed states, each of which has a pair of two substantially parallel sides of four substantially rectangular sides. of the set of substantially parallel second end sides, at a predetermined set of the two-edge side part, while welded to each and one heat transfer section adjacent watertight, adjacent the other of the heat transfer unit and the predetermined set The first flow in the longitudinal direction through which the water vapor G obtained by the flash evaporator 20 passes between the heat transfer portions 25 and is integrated with each other by water-tight welding at two different end portions of the other set different from the two end sides. The path 24a and the second horizontal flow paths 24b through which the seawater W as the cooling water passes are formed every other path, and pass through the water vapor and the second flow paths 24b through the first flow paths 24a. The heat exchange unit forms a cross flow with the seawater, and separates the water vapor G and the seawater W from each other. A Configurations disposed Kakuden'netsu portion within said vacuum chamber 21 in a state of being combined with the casing 26 for guiding between 25. A decompression exhaust device is connected to the rear stage side of the condenser 24 through a pipe line to decompress the inside of the decompression container 21 that houses the condenser 24.

  Each of the first flow paths 24a of the condenser 24 is divided into three flow path groups with two heat transfer sections separated by a predetermined distance near the center, and the two flow path groups at both ends are respectively connected to the flash evaporator. 20, the main condensing sections 24c and 24d that directly flow in the water vapor G obtained in 20 are provided in the central flow path group having a smaller number than the main condensing sections 24c and 24d. This is a mechanism used as the auxiliary condensing unit 24e for allowing the uncondensed water vapor G to pass through.

  Next, the operation of the seawater desalination apparatus according to the present embodiment will be described. As in the first embodiment, seawater taken from the sea was introduced as cooling water into the condenser 24 through the first half of the intake pipe 53 of the main desalination apparatus 50, and the heat transfer section 25 was separated by the condenser 24. Instead of cooling and condensing the steam by heat exchange with the steam, the temperature rises and the condenser 24 exits the latter state of the intake pipe 53 at this elevated temperature and is introduced into the main desalination apparatus 50. Is done. As in the first embodiment, the seawater evaporates a part of water by the main desalination apparatus 50, and this is made fresh water. Seawater that has not evaporated to the end in the main desalination apparatus 50 but whose temperature has been slightly raised from the time of introduction is discharged to the drain pipe 54 and led to the flash evaporator 20.

  Seawater is sprayed upward in the form of a mist from a number of nozzles 22 disposed in the decompression vessel 21 in the decompression vessel 21 of the flash evaporator 20, and a part of the water phase changes to vapor by flash evaporation, and at the same time The temperature drops. The vapor obtained by the evaporation of moisture passes through the separator 23 and flows into the condenser 24 in the same decompression vessel 21. Since the evaporating part and the condensing part are integrally accommodated in the decompression vessel 21, the pressure loss in the flow of water vapor from the evaporating side to the condensing side can be reduced.

  In the condenser 24, first, in the outer main condensing units 24c and 24d, the water vapor G is cooled by exchanging heat with the seawater W having a low temperature via the heat transfer unit 25, and condensed on the surface of the heat transfer unit 25 to be salinized. Water drops that do not contain. The uncondensed water vapor G escapes under the main condensing parts 24c and 24d, then turns upward and flows into the central auxiliary condensing part 24e, and again exchanges heat with the sea water W having a low temperature via the heat transfer part 25. As a result, further condensation occurs. By disposing the condensing portion in two stages in this way, uncondensed water vapor flowing toward the decompression exhaust apparatus can be reliably condensed, the load on the decompression exhaust apparatus can be reduced, and the yield of fresh water can be increased.

  As described above, in the seawater desalination apparatus according to the present embodiment, the condenser 24 is accommodated in the decompression vessel 21 of the flash evaporator 20, and the evaporator and the condenser are integrally disposed. Since the water vapor obtained at 20 can enter the condenser 24 as it is, it is easy to maintain the reduced pressure, and the vapor can be reliably condensed by reaching the condenser 24 in the gas phase. The whole process from evaporation to condensation can be advanced smoothly and the efficiency of condensation can be improved, and the exhaust from the decompression vessel 21 can be led directly to the decompression exhaust device and discharged, making the entire device simple and compact. As a simple structure, the cost can be reduced. Further, the condenser 24 combined with the substantially plate-shaped heat transfer section 25 is used, and the portion for condensing the water vapor is divided into the main condensing sections 24c and 24d and the auxiliary condensing section 24e, and the main condensing sections 24c and 24d are separated. Since the uncondensed water vapor that has passed through is passed through the auxiliary condensing unit 24e and the opportunity for condensation with respect to the water vapor is set twice, condensation can be performed more efficiently with one condenser 24, and the rear side of the condenser 24 It is not necessary to separately provide an auxiliary condenser or the like.

  In the seawater desalination apparatus according to the above-described embodiment, another seawater desalination apparatus (main desalination apparatus 50) is used as a heat radiating means for releasing heat to the seawater to increase the temperature of the seawater, and discharging the seawater. The temperature of the generated seawater is set to be at least 5 ° C. higher than the temperature at the inlet of the condensing unit 52. Use as a medium to exchange heat with each other to lower the temperature of the exhaust heat holding fluid, while increasing the temperature of the seawater from before the heat exchange, and exhaust heat recovery heat exchanger, for example, a high temperature exhausted from a predetermined internal combustion engine It can also be used as a heat exchanger that exchanges heat between the exhaust gas and seawater, or a heat exchanger that exchanges heat between the cooling water or cooling gas that has reached a high temperature of the internal combustion engine, and seawater, especially by reducing the exhaust gas temperature. To the surrounding environment Effect be suppressed. In addition to the internal combustion engine, the exhaust heat source may be various plants that have already been generally used for exhaust heat, such as a power plant, an ironworks, and a garbage incineration facility.

  Further, in the seawater desalination apparatus according to the embodiment, the main desalination apparatus 50 as the heat radiating means is a recovery unit that condenses the working fluid using seawater as cooling water in a predetermined steam power plant as a seawater heater. Although it is set as the structure which raises the temperature of seawater from the condensation part 52 inlet temperature using the water device 60, it is not restricted to this, A heater is for cooling seawater with respect to the waste heat holding fluid discharged | emitted from the predetermined | prescribed waste heat source. Use as a medium to exchange heat with each other to lower the temperature of the exhaust heat holding fluid, while increasing the temperature of the seawater from before the heat exchange, and exhaust heat recovery heat exchanger, for example, a high temperature exhausted from a predetermined internal combustion engine It is also possible to use a heat exchanger that exchanges heat between the exhaust gas and seawater, or a heat exchanger that exchanges heat between cooling water or cooling gas that has reached a high temperature of the internal combustion engine and seawater.

It is a schematic structure explanatory drawing of the seawater desalination apparatus which concerns on the 1st Embodiment of this invention. It is schematic structure explanatory drawing of the flash evaporator and condenser in the seawater desalination apparatus which concerns on the 2nd Embodiment of this invention. It is a principal part schematic perspective view of the condenser in the seawater desalination apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the conventional seawater desalination apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Seawater desalination apparatus 10,20 Flash evaporator 11,21 Depressurization container 12,22 Nozzle 13,23 Separator 14 Depressurization deaeration apparatus 15 Condenser 16,25 Heat transfer part 17 Depressurization exhaust apparatus 18 Tank 24 Condenser 24a 1st flow path 24b 2nd flow path 24c, 24d Main condensing part 24e Auxiliary condensing part 26 Casing 50 Main desalination device 51 Casing 52 Condensing part 53 Intake pipe 54 Drain pipe 60 Condenser 101 Flash chamber 102 Separator 103, 104 Condenser G Water vapor W Seawater

Claims (5)

In the seawater desalination apparatus provided with a predetermined heat radiating means for releasing heat to the seawater taken in as a heat exchange medium and discharging the seawater at a high temperature,
A spray flash type flash evaporator that discharges the remaining seawater that has not been evaporated, while jetting seawater in a substantially mist form to partially evaporate the water in a container reduced to a predetermined pressure below atmospheric pressure,
Including at least a condenser that uses seawater as cooling water, cools and condenses the water vapor obtained in the flash evaporator, and obtains water containing no salt.
Two sets of the condenser, each of the heat transfer parts made of a substantially rectangular thin metal plate in a parallel state, each grouped with two ends that are substantially parallel to the four sides of the substantially rectangle as one set. Among two substantially parallel sides, a predetermined set of two end portions are welded to one adjacent heat transfer section in a water-tight manner, while another adjacent heat transfer unit and the predetermined set of two ends The first flow path through which the water vapor obtained by the flash evaporator passes between each heat transfer section and the sea water as the cooling water are integrated with each other by water-tight welding at the two end sides of another set different from the sides. A second flow path that passes through each other, and the water vapor passing through each of the first flow paths and the seawater passing through each of the second flow paths is a heat exchange unit that forms a cross flow,
Each first flow path of the condenser is divided into three flow path groups with two predetermined heat transfer sections as a boundary, and the two flow path groups at both ends directly flow in water vapor obtained by the evaporator. On the other hand, the main condensing part is made to be an auxiliary condensing part for inflowing uncondensed water vapor after the central flow path group once passes through the main condensing part,
Seawater used as cooling water in the condenser is supplied to the heat radiating means as the heat exchange medium, while seawater discharged from the heat radiating means is introduced into the flash evaporator. Device. In the seawater desalination apparatus according to claim 1,
The heat dissipating means introduces seawater heated by a predetermined heater into a casing depressurized to a predetermined pressure below atmospheric pressure to evaporate water, and uses seawater introduced from the outside as at least a part of cooling water Is a seawater desalination apparatus that obtains fresh water by cooling and condensing the water vapor generated by the evaporation in the condensing unit, and heating the seawater after being used as cooling water in the condensing unit with the heater A seawater desalination apparatus characterized in that seawater introduced into the casing and discharged from the casing to the outside is at a temperature higher by at least 5 ° C. than the new seawater introduced into the condensing part. In the seawater desalination apparatus according to claim 1,
The heat radiating means exchanges heat with the exhaust heat holding fluid discharged from a predetermined exhaust heat source using seawater as a cooling medium to lower the temperature of the exhaust heat holding fluid, while the temperature of the sea water is lower than before heat exchange. A seawater desalination apparatus, characterized in that it is a heat exchanger for exhaust heat recovery that exhausts at least 5 ° C or higher. In the seawater desalination apparatus according to any one of claims 1 to 3,
The flash evaporator is provided with an injection section for injecting seawater in a substantially mist-like manner in the lower part of the decompression vessel so that the injection direction is upward, and discharges seawater upward. apparatus. In the seawater desalination apparatus according to any one of claims 1 to 4,
The condenser is disposed at the upper center of the decompressed container of the flash evaporator, and the evaporated water vapor flows from the upper side into the main condensing parts at both ends, and once passes through the main condensing part and reaches the lower side. A seawater desalination apparatus characterized by having a structure in which uncondensed water vapor is further allowed to flow upward into a central auxiliary condensing unit and non-condensed gas is discharged from the upper side of the auxiliary condensing unit to the outside of the vessel .