JP6890043B2 - Seawater desalination equipment and seawater desalination method - Google Patents

Description

The present invention relates to a seawater desalination apparatus and a seawater desalination method that are operated under conditions in which the power supply is restricted by the use of natural energy.

For example, in the coastal areas of Africa and Southeast Asia, and in the surrounding island countries, there are many places where water sources are not well prepared, and although stormwater and transportation from land are used to secure domestic water, there is always a shortage of water. In recent years, a seawater desalination business that can self-sufficient domestic water with safe water quality has been promoted, and as a device in this business, a reverse osmosis membrane (Reverse Osmosis Membrane, hereinafter referred to as RO membrane) that can be easily operated and stably operated is called. ) Is known (see, for example, Patent Document 1).

In addition, although electric power is required to operate the above-mentioned seawater desalination apparatus, attempts have been made to utilize electric power generated by natural energy such as solar power, which does not require a power grid. In the case of this seawater desalination device that uses natural energy as the main power source, a system that enables optimum operation of the device according to the amount of electric power supplied and its optimum operation technology are required, and various studies have been conducted (for example, patent documents). 2).

Japanese Unexamined Patent Publication No. 2011-2010 International Publication No. 2014/05/7892

When installing a seawater desalination device on the ground, consideration must be given to the effects of seawater tide differences and storm surges, and the removal of contaminants contained in seawater taken with a strainer or screen. As a countermeasure, it is desirable that the intake pump has a discharge head of 8 m or more, and that the intake pump has a foreign matter passing diameter of 10 mm or more so as not to be clogged with impurities.

When pumping seawater by suction with a land pump, if the land pump is installed at a sufficiently safe height from the sea surface, the seawater will have a negative pressure during suction, and bubbles such as free gas will be generated especially in seawater. It is prone to occur and can often result in inability to pump during pump operation. Even if it does not become impossible to pump water, the fine bubbles generated in the seawater adversely affect the detection of the flow rate detector of the RO membrane device in the subsequent stage, and the bubbles grown in the filter housing etc. damage the high-pressure pump. Is a concern. For this reason, it is considered that a submersible vortex pump is often used to use in a small water volume region with an average water intake flow rate of 50 L / min or less, but the above conditions (unless the pump has an axial power of 0.4 kW or more) In reality, it is difficult to secure a lift of 8 m or more and a foreign matter passage diameter of 10 mm or more).

When a submersible pump is used as the intake pump for a seawater desalination device, when seawater is sent directly from the intake pump to a high-pressure pump without going through a water tank, the discharge flow rate of the intake pump, which has a large capacity for the intake flow rate, is throttled and the pump You will have to operate at a point of use with extremely low efficiency. In addition, when the seawater pumped by the intake pump is temporarily stored in the water tank, it is possible to adjust the operating point of the intake pump to a discharge flow rate with high pump efficiency, but in any case, the intake pump and high pressure There is still a need for power supply to cover both pumps. For this reason, when these are covered by the electric power obtained from photovoltaic power generation, it is necessary to secure a considerable proportion of the electric power required for water intake as well as the electric power used for desalinating seawater. It is a factor that increases the capacity of the power system and the installation space of the solar panel.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a seawater desalination apparatus and a seawater desalination method which are operated under conditions where power supply is restricted by the use of natural energy. There is.

In the diligent study to solve the above problems, the present inventors provided a water tank (seawater tank) for storing seawater between the intake pump and the high-pressure pump, and cut off the intake pump and the high-pressure pump with the seawater tank. We have found that by operating the intake pump and the high-pressure pump alternately, the degree of freedom of the discharge flow rate of the intake pump can be increased, and thereby the discharge flow rate that increases the power efficiency of the intake pump can be selected, and the present invention has been completed.

The seawater desalination apparatus of the present invention that has solved the above problems includes an intake pump for acquiring seawater, a seawater tank connected to the intake pump, a high-pressure pump connected to the seawater tank, and the high pressure. It has a freshwater separation unit connected to a pump and provided with a back-penetrating membrane, and a renewable energy power source connected to the water intake pump and the high-pressure pump via a switch unit, and the water intake pump operates. It is characterized in that the high-pressure pump sometimes stops, and when the high-pressure pump operates, the intake pump stops.

In the seawater desalination apparatus, the ratio of the rated output of the intake pump to the rated output of the high-pressure pump is preferably 0.3 or more.

In the seawater desalination method using the seawater desalination apparatus, the first step of storing the seawater pumped by the intake pump in the seawater tank and the seawater stored in the first step are stored by the high pressure pump. It is preferable that the second step is started after the first step is completed, including a second step of supplying to the freshwater separating section and generating freshwater in the freshwater separating section.

In the seawater desalination method, the ratio of the apparent power of the intake pump to the apparent power of the high-pressure pump is preferably 0.3 to 1.5.

In the seawater desalination method, the discharge flow rate of the intake pump is preferably 10 times or more the discharge flow rate of the high-pressure pump.

According to the seawater desalination apparatus and the seawater desalination method of the present invention, the intake pump and the high-pressure pump are cut off by the seawater tank and the intake pump and the high-pressure pump are operated alternately to increase the degree of freedom of the discharge flow rate of the intake pump. , It is possible to select a discharge flow rate that increases the power efficiency of the intake pump (hereinafter, may be simply referred to as "pump efficiency"). Therefore, the power consumption of the entire seawater desalination apparatus can be suppressed to a low level, and the capacity of the power generation system including the photovoltaic power generation system and the installation space of the solar panel can be made compact.

It is an example of the schematic block diagram of the seawater desalination apparatus which concerns on embodiment of this invention. This is an example of a schematic configuration diagram of a conventional seawater desalination apparatus. This is an example of a performance curve diagram of an intake pump used in a conventional seawater desalination apparatus. This is an example of a performance curve diagram of an intake pump used in the seawater desalination apparatus according to the embodiment of the present invention. It is another example of the schematic block diagram of the seawater desalination apparatus which concerns on embodiment of this invention. This is an example of a schematic diagram showing the effect of reducing the power supply capacity in the seawater desalination apparatus according to the embodiment of the present invention. (A) is an example of a schematic diagram showing a power supply capacity in a conventional seawater desalination apparatus, and (b) is an example of a schematic diagram showing a power supply capacity in a seawater desalination apparatus according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments, and is carried out with modifications to the extent that it can be adapted to the gist of the above and the following. It is also possible, all of which are within the technical scope of the invention. In the following description, the same parts are designated by the same reference numerals.

FIG. 1 is an example of a schematic configuration diagram of a seawater desalination apparatus according to an embodiment of the present invention. The seawater desalination apparatus of the present invention uses the electric power generated by a solar cell panel or the like as driving power to store seawater pumped from the water in a seawater tank, and then boosts the seawater with a high-pressure pump to desalinate the seawater. It is supplied to the freshwater separation section, subsequently treated in the freshwater separation section, and produces freshwater as the treated water.

As shown in FIG. 1, the seawater desalination apparatus 1 includes an intake pump 3 for acquiring seawater 2, a seawater tank 4 connected to the intake pump 3, a high-pressure pump 5 connected to the seawater tank 4, and the like. It has a freshwater separation unit 6 connected to the high-pressure pump 5, and a natural energy source 8 connected to the water intake pump 3 and the high-pressure pump 5 via a switch unit 7. That is, in the seawater desalination device 1 of the present invention, the water intake pump 3 and the high pressure pump 5 are cut off by the seawater tank 4 by providing a water tank (seawater tank 4) for storing the seawater 2 between the water intake pump 3 and the high pressure pump 5. It is a structure that has been made to. Further, the water intake pump 3 and the high pressure pump 5 are configured such that the high pressure pump 5 is suspended when the water intake pump 3 is operated and the water intake pump 3 is suspended when the high pressure pump 5 is operated by switching the switch unit 7. Therefore, the water intake pump 3 and the high-pressure pump 5 do not operate at the same time, but are operated alternately, for example.

The above configuration will be described below using the performance curve of the pump. FIG. 2 is an example of a schematic configuration diagram of a conventional seawater desalination apparatus, and is not a system in which the intake pump 103 and the high-pressure pump 105 are operated alternately, but when the high-pressure pump 105 is operating (simultaneous operation with the supply pump 104). Basically, the water intake pump 103 is always operating. Further, FIG. 3 is an example of a performance curve diagram of an intake pump used in a conventional seawater desalination apparatus, and FIG. 4 is a performance curve diagram of an intake pump used in the seawater desalination apparatus according to the embodiment of the present invention. This is an example.

As shown in FIG. 2, in the case of the conventional seawater desalination apparatus 101, the seawater 2 is directly sent from the intake pump 103 to the high pressure pump 105 without going through the seawater tank. In this case, the intake pump 103 is shown in FIG. As shown, for example, a pump having a water intake flow rate of 8.15 L / min and a rated output of 0.4 kW is used, which has a large rated output for the water intake flow rate. If such a pump is adopted and operated at the same time as the high-pressure pump, the discharge flow rate will be reduced to 8.15 L / min, and the pump efficiency at this time will have to be operated at an extremely low usage point of about 5%. I don't get it.

On the other hand, as shown in FIG. 1, in the case of the seawater desalination apparatus 1 of the present invention, a seawater tank 4 for storing seawater 2 is provided between the water intake pump 3 and the high pressure pump 5, and the water intake pump 3 and the high pressure pump 5 are operated alternately. It is something that makes you. Thereby, the discharge flow rate of the water intake pump 3 can be independently determined regardless of the water intake amount of the high pressure pump 5. Therefore, the water intake pump 3 can be operated by selecting a discharge flow rate that increases the power efficiency. In this case, the water intake pump 3 is set to be equal to or less than the power supply capacity (apparent power) of the high pressure pump 105 when the water intake pump 103 and the high pressure pump 105 of the conventional seawater desalination apparatus 101 are operated at the same time. It is preferable to set it. For example, as shown in FIG. 4, a pump having a rated output of 0.75 kW is selected as a pump that secures a lift of the water intake pump 3 of 8 m or more and can take the discharge flow rate as large as possible. When such a pump is used to draw a lift of 8 m or more, the discharge flow rate can be increased to 250 L / min, and the pump efficiency at this time can be operated at a large usage point of about 47%.

As described above, by adopting the configuration of the seawater desalination apparatus 1 of the present invention, the discharge flow rate of the intake pump 3 can be made much larger than the discharge flow rate of the high pressure pump 5, for example. The intake pump 3 can be operated at a point of use where the pump efficiency is high.

The ratio of the rated output of the intake pump 3 to the rated output of the high-pressure pump 5 is preferably 0.3 or more. When the ratio of the rated output is 0.3 or more, the rated output of the intake pump 3 can be provided to a level comparable to that of the high pressure pump 5, more preferably 0.5 or more, still more preferably 0.8 or more. good. Further, when the ratio of the rated output is 1.5 or less, the intake pump 3 can be operated without impairing the discharge flow rate and the discharge head of the high pressure pump 5, more preferably 1.3 or less, and further. It is preferably 1.1 or less.

Further, the water intake pump 3 preferably has a discharge head of 8 m or more, and further preferably has a foreign matter passing diameter of 10 mm or more so as not to be clogged with impurities in seawater.

It is more preferable to use an axial type or a plunger type in which the plunger (piston) reciprocates in parallel with the center line of the cylinder block as the high pressure pump 5. This type of pump generally has a high pump efficiency of about 80% while having a small capacity and a high lift, so that the power consumption of the high pressure pump 5 can be kept low.

The freshwater separation unit 6 is provided with an RO membrane (not shown), and produces freshwater from the seawater 2 supplied from the high-pressure pump 5. Specifically, the high-pressure pump 5 boosts and supplies the seawater 2 so that the osmotic pressure of the seawater 2 is equal to or higher than the osmotic pressure of the seawater 2, and desalting the seawater 2 at the freshwater separation unit 6 to obtain freshwater.

As shown in FIG. 1, it is preferable that the freshwater separation unit 6 is provided with an energy recovery device 9 that recovers and reuses the high-pressure energy of the concentrated water discharged from the RO membrane. By providing this device, the high-pressure energy of the concentrated water is recovered, and the recovered energy is converted into rotational energy and used as a part of the rotational energy of the high-pressure pump. As a result, the power supply capacity of the high-pressure pump 5 can be reduced, and the reduction ratio of the power supply capacity by the implementation of the present invention can be relatively increased. Further, the discharge amount of the high-pressure pump 5 is increased in order to compensate for the decrease in the operating rate of the high-pressure pump 5 (the ratio of the operating time of the high-pressure pump 5 to the total operating time) caused by the alternating operation of the water intake pump 3 and the high-pressure pump 5 ( It is necessary to increase the rotation speed of the high-pressure pump 5), and the increase in the power supply capacity of the high-pressure pump 5 can be suppressed to be small when the energy recovery device 9 is installed.

Regarding energy recovery, for example, a rotating shaft of a high-pressure pump is installed on one shaft of a double-screw motor, and an axial piston type energy recovery device 9 similar to that of a high-pressure pump is installed on the other shaft. The power consumption of the motor can be reduced by converting the recovered power energy into rotational energy and transmitting it to the motor.

As shown in FIG. 1, the switch unit 7 uses the electric power generated by the natural energy source 8 such as a solar cell panel to operate the electric power supply line L1 for operating the water intake pump 3 and the electric power for operating the high-pressure pump 5. This is a switch for switching to the supply line L2. By connecting the switch unit 7 to the power supply line L1, the water intake pump 3 can be operated and the high pressure pump 5 can be stopped. Further, by connecting the switch unit 7 to the power supply line L2, the high pressure pump 5 can be operated and the water intake pump 3 can be stopped. As a result, the water intake pump 3 and the high pressure pump 5 can be operated alternately.

FIG. 5 shows another example of a schematic configuration diagram of the seawater desalination apparatus according to the embodiment of the present invention. As shown in FIG. 5, in configuring the switch portion of the seawater desalination apparatus 1A, the electric power generated by the natural energy source 8 is supplied to the water intake pump 3 in advance and the electric power supply line L1 and the high pressure pump 5 are supplied. It may be branched to the line L2, and switch units 7A and 7B may be provided in the respective power supply lines L1 and L2 to switch ON / OFF respectively.

As a natural energy source 8, various power generation energies such as solar power generation, wind power generation, and hydroelectric power generation can be used. However, especially when it is carried out in the coastal areas of Southeast Asia and the surrounding island countries, sunlight can be used due to climatic and geographical conditions. It is more preferable to use power generation.

Further, as shown in FIG. 1, in the seawater desalination apparatus 1 of the present invention, a cartridge filter 10 is provided between the seawater tank 4 and the high-pressure pump 5, and a supply pump is further provided between the seawater tank 4 and the cartridge filter 10. 11 may be provided. With such a configuration, foreign matter mixed in the seawater can be removed, and the seawater supply in the seawater desalination apparatus 1 can be smoothly performed.

Next, a seawater desalination method using the seawater desalination apparatus 1 of the present invention will be described.
In the method of desalinating seawater using the seawater desalination apparatus 1 of the present invention, first, the seawater 2 pumped up to the ground by the intake pump 3 is stored in the seawater tank 4 (first step). Specifically, the seawater 2 is pumped up by using an intake pump 3 having a discharge head of 8 m or more and a foreign matter passing diameter of 10 mm or more so as not to clog the contaminants in the seawater 2. Is stored in the seawater tank 4.

Further, the seawater 2 stored in the seawater tank 4 in the first step is supplied to the freshwater separating section 6 by the high-pressure pump 5, and the freshwater separating section 6 generates freshwater (second step). Specifically, the axial piston type high-pressure pump 5 supplies the seawater 2 stored in the seawater tank 4 to the freshwater separation unit 6, and the freshwater separation unit 6 generates freshwater and the discharged concentrated water is energy. It is sent to the recovery device 9. The power energy recovered by the energy recovery device 9 is converted into rotational energy and transmitted to the motor, so that the power consumption of the motor can be reduced.

Here, the seawater desalination method using the seawater desalination apparatus 1 of the present invention is characterized in that the second step starts after the first step is completed. That is, the first step and the second step are not performed at the same time, and when the first step is in the execution state, the second step is in the hibernation state. Further, when the second step is in the execution state, the first step is in the hibernation state. By using such a method, the operation of the intake pump 3 performed in the first step and the operation of the high pressure pump 5 performed in the second step can be alternately performed. Further, the operating time of the water intake pump 3 during the operating time of the seawater desalination device 1 is shortened, and the burden on the water intake pump 3 is reduced. In this case, the water intake pump 3 is set to be equal to or less than the power supply capacity (apparent power) of the high pressure pump 105 when the water intake pump 103 and the high pressure pump 105 of the conventional seawater desalination apparatus 101 are operated at the same time. All you have to do is set the power capacity. In this method, the intake pump 3 can be selected according to the power supply capacity of the high-pressure pump 5, so that the discharge flow rate of the intake pump 3 can be made larger than the discharge flow rate of the high-pressure pump 5.

In the seawater desalination method of the present invention, the ratio of the apparent power of the intake pump 3 to the apparent power of the high-pressure pump 5 is preferably 0.3 to 1.5. If the ratio of the apparent power is less than 0.3, the discharge flow rate of the intake pump 3 is small and the operating rate of the high-pressure pump 5 is lowered, so that the productivity is lowered. To compensate for this, the capacity of the high-pressure pump 5 and the freshwater separation unit 6 must be significantly increased. If the ratio of the apparent power is 0.3 or more, the discharge flow rate of the intake pump 3 can be 10 times or more the discharge flow rate of the high pressure pump 5, and the operating rate of the high pressure pump is maintained as high as 90% or more. be able to. The apparent power ratio is more preferably 0.7 or more, still more preferably 1.0. When the ratio of the apparent power exceeds 1.0, the apparent power of the intake pump 3 is larger than the total load of the high-pressure pump 5 and the supply pump 11 operating at the same time as the high-pressure pump 5 (hereinafter referred to as the high-pressure pump or the like). There is a possibility of becoming. When the apparent power of the intake pump 3 is larger than that of the high-pressure pump or the like, the apparent power of the intake pump 3 determines the power supply capacity. Therefore, the apparent power of the intake pump 3 should not exceed the apparent power of the high-pressure pump or the like. preferable. The condition in which the effect of the present invention can be maximized is that the apparent power of the intake pump 3 is equal to the apparent power of the high-pressure pump or the like. The effect of the present invention is not lost, and the effect of the present invention can be expected if the ratio of the apparent power is 1.5 or less.

Further, it is preferable that the discharge flow rate of the water intake pump 3 is 10 times or more the discharge flow rate of the high pressure pump 5. When the discharge flow rate is 10 times or more, the time during which the high-pressure pump 5 is stopped during the operation of the intake pump 3 can be shortened, and the operating rate of the high-pressure pump 5 can be maintained as high as 90% or more. Further, when the decrease in freshwater productivity due to the decrease in the operating rate of the high-pressure pump 5 is covered by increasing the discharge flow rate or the discharge pressure of the high-pressure pump 5, the increase in power supply capacity can be suppressed to a low level. The discharge flow rate is more preferably 15 times or more, still more preferably 20 times or more.

Using the seawater desalination apparatus of the present invention shown in FIG. 1, a demonstration experiment was conducted on the effect of reducing the power supply capacity.

The configuration of the seawater desalination system is as shown below.
Intake pump: Submersible titanium pump for seawater (Tsurumi Seisakusho 50TM type, lift 8 m or more, foreign matter passage diameter 10 mm or more)
High-pressure pump: Axial piston type (manufactured by Danfoss, model number: APP1.0)
Supply pump: Magnet type (made by Iwaki, model number: MD-40RZ-5)
Freshwater separation part: Hollow fiber reverse osmosis membrane (Toyobo Holosep) Model number: HR5255PI
Renewable energy source: Solar power generation

In the demonstration experiment, first, the discharge flow rate, the discharge head, and the apparent power of each pump when the intake pump 3 and the high-pressure pump 5 were operated alternately were measured by switching the switch unit 7. The apparent power was obtained from the product of the voltage measurement value and the current measurement value of the supplied DC power supply. The supply pump 11 was operated at the same time as the high pressure pump 5.

Comparative example

A demonstration experiment was conducted on the effect of reducing the power supply capacity using the conventional seawater desalination apparatus shown in FIG. In the demonstration experiment, the discharge flow rate, discharge head, and apparent power of each pump when the intake pump 103 and the high-pressure pump 105 were operated at the same time were measured. The apparent power of each pump was calculated in the same manner as in the examples.

Table 1 shows various characteristics (discharge flow rate, discharge head, rated output) and apparent power values of the intake pump, the high pressure pump, and the supply pump used in the above Examples and Comparative Examples, respectively. Table 1 shows the power supply capacities of the natural energy sources used in the examples and comparative examples of the present invention. In the case of the embodiment of the present invention, the power supply capacity must be adjusted to the apparent power of the intake pump or the total apparent power of the high-pressure pump and the supply pump, whichever is larger. The total apparent power of the pump and the supply pump was larger, and the value was 1.33 [kVA]. On the other hand, in the case of the comparative example, since the intake pump, the high-pressure pump, and the supply pump are operated at the same time, the required apparent power is the total apparent power of the intake pump, the high-pressure pump, and the supply pump. It is 1.93 [kVA].

From the results in Table 1, the reduction rate of the power supply capacity in the seawater desalination apparatus of the present invention was calculated. The reduction rate can be calculated by the following formula (1).
Reduction rate (%) = (Power capacity in simultaneous operation-Power capacity in alternate operation) / Power capacity in simultaneous operation x 100 ... (1)

That is, when the water intake pump and the high-pressure pump are operated alternately, the power supply capacity can be reduced by about 31% (= 1.93-1.33) /1.93 × 100 as compared with the case where the pumps are operated at the same time. I understand. In other words, it can be seen that the power supply capacity can be reduced by about 30% without changing the productivity in the alternate operation of the intake pump and the high pressure pump.

Based on the results in Table 1, FIGS. 6 (a) and 6 (b) show schematic views of the state of the power supply capacity in the seawater desalination apparatus. FIG. 6A is an example of a schematic diagram showing the power supply capacity in the conventional seawater desalination apparatus, and FIG. 6B is a schematic diagram showing the power supply capacity in the seawater desalination apparatus according to the embodiment of the present invention. An example is shown.

As shown in FIG. 6A, in the case of the conventional seawater desalination apparatus, the power supply capacity consumed by the intake pump, the high-pressure pump, and the supply pump located upstream of the high-pressure pump and operated at the same time as the high-pressure pump. The sum is the minimum power capacity required for the device.

As shown in FIG. 6B, in the case of the seawater desalination apparatus according to the embodiment of the present invention, the operation of the intake pump in the first step and the operation of the high-pressure pump and the supply pump in the second step are alternately performed. As a result, the power supply capacity of the seawater desalination equipment is the sum of the power supply capacities consumed by the high-pressure pump and the supply pump, and the power supply capacity of the equipment should be reduced as compared with the case of simultaneous operation in FIG. 6 (a). Can be done. In the example of FIG. 6 (b), the operating time of the high-pressure pump is reduced by 3.3% as compared with the example of FIG. 6 (a), so that the freshwater productivity is the same as that of the case of FIG. 6 (a). In order to do so, the rotation speed of the high-pressure pump was increased and the amount of permeated water was increased by 3.3%. As a result, the amount of electric power that drives the high-pressure pump increased by 4.5%.

Since the effect of reducing the power supply capacity obtained by the present invention is due to the reduction of the electric power required for operating the intake pump, the larger the power supply capacity of the intake pump used when the present invention is not applied, the more the reduction can be achieved. The power capacity increases. Further, as the power supply capacity of the high-pressure pump or the like is smaller than the power supply capacity of the water intake pump, the reduction rate of the power supply capacity can be increased.

If the electric capacity of the intake pump in simultaneous operation is larger than that of the above example because the required lift of the intake pump is larger than that of the above example, there is a possibility that the reduction of the power supply capacity can be further increased.

As described above, the seawater desalination apparatus and the seawater desalination method of the present invention can improve the operating efficiency of the intake pump and reduce the power supply capacity. It is possible to make the capacity of the power generation system and the installation space of the solar panel compact.

The seawater desalination apparatus and the seawater desalination method of the present invention are not limited to simply obtaining freshwater, but also include the case of using concentrated seawater. For example, it is also possible to separately store and dry the concentrated water obtained in the freshwater separating section 6 in FIG. 1 to obtain natural sea salt. In this case, the salinity of the concentrated water is about twice that of the original seawater. For example, the process time can be shortened as compared with the method of concentrating the seawater pumped from the water, and the productivity of the natural sea is improved. You can get salt.

1 Seawater desalination equipment 1A Seawater desalination equipment 101 Seawater desalination equipment 2 Seawater 3 Intake pump 103 Intake pump 4 Seawater tank 5 High-pressure pump 105 High-pressure pump 6 Freshwater separation unit 7 Switch unit 7A Switch unit 7B Switch unit 8 Renewable energy source 9 Energy recovery device 10 Cartridge filter 11 Supply pump 104 Supply pump L1 Power supply line L2 Power supply line

Claims (5)

With an intake pump that acquires seawater,
The seawater tank connected to the intake pump and
The high-pressure pump connected to the seawater tank and
A freshwater separator connected to the high pressure pump and provided with a reverse osmosis membrane,
It has a renewable energy power source connected to the intake pump and the high-pressure pump via a switch unit.
When the intake pump operates, the high-pressure pump stops, and when the high-pressure pump operates, the intake pump stops .
The intake pump, seawater desalination apparatus characterized by have a more discharge lift 8m. The seawater desalination apparatus according to claim 1, wherein the ratio of the rated output of the intake pump to the rated output of the high-pressure pump is 0.3 or more. In the seawater desalination apparatus according to claim 1 or 2.
The first step of storing the seawater pumped by the intake pump in the seawater tank, and
The seawater stored in the first step is supplied to the freshwater separation section by the high-pressure pump, and the freshwater separation section includes a second step of generating freshwater.
A seawater desalination method in which the second step starts after the first step is completed. The seawater desalination method according to claim 3, wherein the ratio of the apparent power of the intake pump to the apparent power of the high-pressure pump is 0.3 to 1.5. The seawater desalination method according to claim 3 or 4, wherein the discharge flow rate of the intake pump is 10 times or more the discharge flow rate of the high-pressure pump.

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