JP4092649B2 - Seawater desalination equipment - Google Patents

Description

  The present invention relates to an apparatus for desalinating seawater.

As is well known, a reverse osmosis membrane method or an electrodialysis method is generally used as a method for desalinating seawater. In the reverse osmosis membrane method, pure water is produced by filtering salt content in seawater by applying a high pressure of about 100 atm in a direction opposite to the osmotic pressure to a membrane having a very fine hole of about 1 nanometer. Is. In electrodialysis, a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between an anode and a cathode, and seawater is passed between the ion exchange membranes, so that anions in the seawater are removed. It draws to the anode side and passes through the anion exchange membrane, draws cations to the cathode side and passes through the cation exchange membrane to separate seawater into agricultural salt water and fresh water. Such an electrodialysis method is also commonly used as a salt production method, and Patent Literature 1 and Patent Literature 2 propose that salt production and desalination are simultaneously performed by the electrodialysis method.
JP-A-8-89958 JP-A-8-318136

  By the way, in order to implement the conventional desalination methods as described above, all of them require a large-scale desalination plant, and of course, considerable land is required for that purpose. In addition, the use of solar cells as the power source for this type of desalination plant is also under consideration. However, since this type of large-scale desalination plant requires a large capacity and stable power source, When using solar cells, it requires not only large-area solar panels but also a complex and sophisticated power supply system equipped with large-capacity batteries, charge / discharge controllers, inverters, etc. Therefore, not only equipment costs but also maintenance costs It must be bulky.

  For this reason, conventional desalination plants that use solar cells are difficult to apply to relatively small-scale plants, and the development of desalination equipment that is more compact and simple, is inexpensive, and is easy to maintain. It was desired.

  The invention according to claim 1 is an apparatus for desalinating seawater by being floated on the sea surface, the float for floating the entire apparatus on the sea surface, and a seawater desalination system provided in a submerged state below the sea surface. The electrodialysis apparatus to be treated, a freshwater tank for storing the treated freshwater, and a solar battery panel provided on the sea surface and serving as a power source for the electrodialysis apparatus.

  The invention of claim 2 is the desalination apparatus of the invention of claim 1, wherein the fresh water tank is formed into a vertically long tube shape and its lower part is submerged in the sea and its upper part is projected above the sea surface, and the fresh water tank An adjustment mechanism for adjusting the buoyancy of the entire desalination apparatus and the desalination apparatus and stabilizing the posture is attached to the lower part of the apparatus.

  A third aspect of the invention is the desalination apparatus of the first or second aspect of the invention, wherein the electrodialysis apparatus passes the seawater through a plurality of ion exchange membranes arranged between the electrodes by a pump. The solar cell panel is configured to directly supply a DC voltage to the electrode and pump in the electrodialysis apparatus.

  The invention of claim 4 is the desalination apparatus of claim 1, 2 or 3, wherein the electrodialysis apparatus chlorinates seawater to be desalinated by chlorine generated at the anode during the desalination treatment. It is said that it is said.

  The invention of claim 5 is the desalination apparatus of the invention of claim 1, 2, 3 or 4, wherein the electrodialysis apparatus passes seawater to be desalinated as an upward flow between the ion exchange membranes, The seawater to be formed is configured to pass between the ion exchange membranes as a downward flow.

  The desalination apparatus of the invention of claim 1 is mainly composed of an electrodialysis apparatus, a fresh water tank, and a solar cell panel, and the whole is floated on the sea surface by a float, and in particular, the electrodialysis apparatus is submerged under the sea surface. Because it is installed in a state, it does not require a site for installation, the entire device can be configured in a simple and compact manner, requires almost no daily maintenance, and processing costs can be sufficiently reduced, and a small-scale desalination system As best.

  The desalination apparatus according to the invention of claim 2 makes the whole apparatus simple and inexpensive by assembling a small number of simple parts by attaching a vertical tube-shaped fresh water tank as a main frame and attaching other components to it. It can be manufactured and can float on the sea surface with a stable posture.

  Since the desalination apparatus according to the invention of claim 3 is configured to directly supply the direct current voltage, which is the output of the solar cell panel, to the electrodialysis apparatus, auxiliary equipment such as a battery is unnecessary, and the power supply facility and the electric circuit are It can be simplified and energy conversion loss is minimal.

  The desalination apparatus of the invention of claim 4 can naturally sterilize the fresh water with chlorine using chlorine generated at the anode during the desalination treatment by the electrodialysis apparatus.

  The desalination apparatus of the invention of claim 5 can efficiently separate fresh water and agricultural salt water by utilizing a specific gravity difference caused by a change in salinity concentration during desalination treatment by an electrodialysis apparatus.

  1 to 5 show an embodiment of a desalination apparatus of the present invention. FIG. 1 shows three desalination apparatuses, each of which desalinates seawater by electrodialysis and uses solar cells as its power source. Each desalination device is installed by being floated on the sea surface by its own buoyancy, and is sufficiently compact and has a very simple configuration. Note that the processing capacity of the desalination apparatus of the present embodiment is assumed to be, for example, about 200 liters / day (equivalent to the amount of water used per day by one household).

  The desalination apparatus of the present embodiment is processed with a float 1 having a buoyancy that can float the entire apparatus on the sea surface, an electrodialysis apparatus 2 that is provided under the sea surface, and desalinates seawater. The fresh water tank 3 for storing fresh water and a solar cell panel 4 as a power source for the entire apparatus are mainly configured. In particular, the fresh water tank 3 has a vertically long tube shape also serving as a main frame of the entire apparatus. It is set as the structure which attached these components.

  That is, as shown in FIGS. 2 to 3, in the desalination apparatus of the present embodiment, the fresh water tank 3 has a vertically long tapered tube shape (for example, a maximum diameter of 225 mmφ, an overall height of 4.8 m, an internal capacity of about 200 liters). In addition, six arms 5 are radially attached around the intermediate portion, and the fresh water tank 3 and the arms 5 constitute a main frame that can be called a skeleton of the entire apparatus. Then, a triangular float 1 is attached between the arms 5, and the buoyancy of the float 1 causes the fresh water tank 3 to be in a standing state with its lower half submerged below the sea surface and the upper half projecting above the sea surface. The ballast tank 6, the electrodialyzer 2 and the weight 7 are attached below the sea surface of the fresh water tank 3, and the solar cell panel 4 is attached on the arm 5. The ballast tank 6 and the weight 7 together with the float 1 function as an adjustment mechanism for adjusting the buoyancy of the entire apparatus and maintaining its posture stably. The ballast tank 6 and the weight 7 and the electrodialysis apparatus 2 The buoyancy of the entire apparatus is optimally adjusted by the weight of the device, and a stable posture is always maintained.

  By attaching the arm 5 to the fresh water tank 3 and attaching the solar cell panel 4 to the arm 5 by a hinge capable of absorbing relative deformation, it is possible to apply an excessive force to each part even if the entire apparatus swings. Can be prevented. In addition, fresh water can be taken out freely by incorporating a take-out pipe 8 inside the fresh water tank 3 and attaching a discharge port 9 connected thereto to the upper part of the fresh water tank 3. It is preferable that a person can get on the solar cell panel 4.

The solar cell panel 4 in the present embodiment is made of, for example, crystal laminated glass. In the illustrated example, six modules each having a regular triangular shape with a side of about 2 m form a hexagon as a whole. It is mounted on the arm 5 and has a total area of about 10 m ² and a total output of about 1.2 kW. This solar cell panel 4 directly supplies a direct-current voltage to the electrode 10 and the pump 13 of the electrodialysis apparatus 2 to be described later without requiring any other accessories such as a battery, a charge / discharge controller, and an inverter. It is supposed to be.

  The electrodialysis apparatus 2 includes a plurality of ion exchange membranes 11 (cation exchange membranes 11a and anion exchange membranes 11b) between a pair of electrodes 10 (anode 10a and cathode 10b) as shown in a conceptual diagram in FIG. Alternatingly arranged, fresh water is electrodialyzed by passing seawater through each flow path 12 (desalination flow path 12a, agricultural salinization flow path 12b, and auxiliary flow paths 12c, 12d) formed between them. It is configured to be separated into farm salt water and a pump 13 for that purpose. The pump 13 sucks seawater, branches and supplies it to each flow path 12 through the filtration filter 14, guides the fresh water that has passed through the desalination flow path 12a to the fresh water tank 3, and the agricultural salt water flow path 12b. It has a flow rate and a head that can discharge the seawater that has become agricultural saltwater through the sea to the sea as it is. Assuming that the processing capacity per day is about 200 liters as described above, the processing capacity per hour is about 50 liters / H, assuming that the operating time per day (average sunshine duration) is about 4 hours. It is preferable that

  Moreover, in the electrodialysis apparatus 2 of this embodiment, as shown in FIG. 4, the seawater to be desalinated is guided to the freshwater tank 3 through the desalination flow path 12 a as an upward flow. The seawater to be discharged is released into the sea through the agricultural salinity channel 12b as a downward flow, and as a result, the salinity of the desalinated seawater gradually decreases while it rises in the desalination channel 12a. On the contrary, the seawater to be salinized is gradually increased in salinity while descending the agricultural salinization channel 12b, and the specific gravity is increased. Agricultural salt water and fresh water are efficiently separated. Further, the seawater to be desalinated is first passed through a preliminary flow path 12c adjacent to the anode 10a, so that chlorine sterilization is naturally performed by chlorine generated there. Hydrogen is generated in the preliminary flow path 12d adjacent to the cathode 10b, but it may be discharged into the sea as it is.

  Since the desalination apparatus of the present embodiment can be used alone, its processing capacity is about 200 liters / day, which is equivalent to the amount of water used per day by one household, as described above. Although one household can use or dedicate a single desalination device, it can be considered that a large number of desalination devices are juxtaposed and used as a joint water system. For example, as shown in FIG. 5, a large number of desalination apparatuses are arranged side by side around a floating pier 20 provided as a walkway on the sea, and the fresh water tanks 3 of each apparatus are connected by a water collecting pipe 21 (see FIG. 1). In addition, the fresh water treated by each device can be guided to a large-capacity storage tank that is separately installed, and then distributed to various places for shared use. In that case, for example, as shown in FIG. 5 (b), the water collection main pipe 22 may be laid under the floating jetty 20. Moreover, as shown in FIGS. 1 to 3, a joint 23 for connecting the devices to each other may be attached to the tip of the arm 5. Of course, the required number of desalination apparatuses can be increased or decreased as needed.

  The desalination apparatus of this embodiment is compactly equipped with all the equipment necessary for desalination, and its configuration is extremely simple, and seawater is efficiently desalinated immediately by floating it on the sea surface. Therefore, there is no need for a special site for installing this, and it can be installed much more easily and cheaply than in the case of a large-scale desalination plant. For example, it is optimal as a small-scale desalination plant on a remote island.

  In particular, since the direct current power source of the solar cell panel 4 is used as it is as the power source of the electrodialyzer 2 without being converted, the solar cell panel 4 and the electrodialyzer 2 are directly connected with a simple series circuit. It can be connected and does not require large-capacity batteries, charge / discharge controllers, inverters, etc., which are indispensable for conventional large-scale desalination plants. The conversion loss is minimal, there is no waste, and an environmentally friendly and highly effective desalination system can be realized.

  Further, the fresh water tank 3 is a vertically long tube that also serves as a main frame, and has a simple configuration in which a small number of components are combined. In particular, not only the electrodialyzer 2 but also a ballast tank as an adjusting mechanism is provided below the fresh water tube 3. 6 and weight 7 are attached, so that not only can it float on the sea surface in a stable posture, but the entire device can be manufactured at a sufficiently low cost, and almost no routine maintenance is required except for the filter 14. In addition, by using a resin having seawater resistance as a material of each component (carbon fiber reinforced resin, polypropylene, olefin rubber, etc. can be suitably employed), it is possible to secure a service life of about 10 years. Therefore, the treatment cost of fresh water can be sufficiently suppressed.

  Furthermore, since the desalination apparatus of this embodiment discharges the agricultural salt water generated in association with desalination of seawater to seawater as it is, the salinity concentration will increase in the sea below this desalination apparatus, As a result, a variety of marine organisms that prefer high salinity can be gathered there, which can be expected to restore ecosystems and purify water in closed waters, and can be used effectively as hydrophilic waters such as fishing points and diving points. There is also.

  Although one embodiment of the present invention has been described above, the above embodiment is an optimal example for carrying out the present invention, and the present invention is not limited to the above embodiment, and appropriate design changes are possible. is there. For example, in the above embodiment, the solar cell panel 4 is a combination of equilateral triangular modules in a hexagonal shape. Therefore, when a large number of desalination apparatuses are arranged in parallel as shown in FIG. There is an advantage that the panels 4 can be connected side by side without a gap, but the present invention is not limited to this, and the shape, area, etc. of the solar cell panel 4 may be set arbitrarily. Of course, the capacity, shape, materials, and combination of all the components including the electrodialyzer 2 and the fresh water tank 3 are optimal in consideration of various conditions such as required processing capacity and surrounding environment. Just design.

It is a figure which shows the external appearance of the desalination apparatus which is one Embodiment of this invention. FIG. FIG. It is a conceptual diagram of an electrodialysis apparatus. It is a figure which shows an example of the joint water use system by many desalination apparatuses similarly.

Explanation of symbols

1 Float 2 Electrodialyzer 3 Freshwater Tank 4 Solar Panel 5 Arm 6 Ballast Tank (Adjustment Mechanism)
7 Weight (adjustment mechanism)
8 Extraction tube 9 Discharge port 10 Electrode 10a Anode 10b Cathode 11 Ion exchange membrane 11a Cation exchange membrane 11b Anion exchange membrane 12 Channel 12a Desalination channel 12b Agricultural salt water channel 12c, 12d Preliminary channel 13 Pump 14 Filtration Filter 20 Floating jetty 21 Water collecting pipe 22 Water collecting main pipe 23 Joint

Claims (5)

  A device that floats on the sea surface and desalinates seawater, a float for floating the entire device on the sea surface, an electrodialysis device that is placed under the sea surface and is submerged, and desalinates seawater, A seawater desalination apparatus comprising: a fresh water tank for storing treated fresh water; and a solar cell panel provided on the sea surface and serving as a power source for an electrodialysis apparatus.   2. The desalination apparatus according to claim 1, wherein the fresh water tank is formed into a vertically long tube shape and its lower part is submerged in the sea and the upper part is protruded above the sea surface. A seawater desalination apparatus comprising an adjustment mechanism for adjusting the buoyancy of the entire desalination apparatus and stabilizing the posture.   The desalination apparatus according to claim 1 or 2, wherein the electrodialysis apparatus separates the seawater into fresh water and agricultural saltwater by passing seawater by a pump between a plurality of ion exchange membranes arranged between the electrodes. The seawater desalination apparatus is characterized in that the solar cell panel is configured to directly supply a DC voltage to the electrode and pump in the electrodialysis apparatus.   The desalination apparatus according to claim 1, 2, or 3, wherein the electrodialysis apparatus is configured to sterilize seawater to be desalinated by chlorine generated at the anode during the desalination process. Seawater desalination equipment. The desalination apparatus according to claim 1, 2, 3 or 4, wherein the electrodialysis apparatus passes seawater to be desalinated as an upward flow between the ion exchange membranes, and seawater to be agricultural salt water as a downward flow. A seawater desalination apparatus characterized by being configured to pass between ion exchange membranes.

Images