JPH0975935A - Reverse osmosis desalting method for sea water making common use of sea water pumping up power plant and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a cost effective operation by desalting the sea water by reverse osmosis with a high-pressure pump by utilizing the midnight excess electric power, driving a generator by utilizing a high-pressure water wheel with the residual pressure of the concd. sea water, lifting the water to a sea water storage bond on a mountain and utilizing this sea water for power generation and desalting in the daytime. SOLUTION: The high-pressure pump 5 is driven by utilizing the midnight excess electric power to gather the offshore clean see water by a water intake pipe 15 and is subjected to dust removal by a dust removing machine 13 and, thereafter, the sea water is lifted to the sea water storage pond 1 on the mountain through a water feed pipe 10 and a pressure return pipe 3. At this time, the sea water is desalted by reverse osmosis in a module unit 7 and is stored in a service water tank 11. Further, the high-pressure water wheel 8 is turned by utilizing the residual pressure of the sea water concd. by this module unit 7, by which the generator 8 is driven to generate electricity. Even in the daytime, the sea water is desalted by the reverse osmosis by utilizing the sea water in the sea water storage pond 1 pumped up in the nighttime and the generator 9 is driven by utilizing the high-pressure water wheel 8 to apportion the electric power to the peak time load electric power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is an infinite seawater system in which each local government or electric power company utilizes the facilities and principles of a seawater pumped-storage power plant for countermeasures against water shortage during abnormal droughts once every several years or decades. The present invention relates to a method for supplying urban waterworks that reverse osmosis desalination as drinking water.

[0002]

2. Description of the Related Art A reverse osmosis desalination system for seawater is considered to be constructed by the local government as a measure against long-term drought due to abnormal weather in recent years, but the construction period is short and there is no technical problem. Although it is close to pure water and ideal as drinking water, the construction cost is mainly large, the equipment is idle for a long period except when there is an abnormal drought, and the unit cost of electricity for desalination is higher than the current water supply. The thing became a fault and adoption was put off.

[0003]

SUMMARY OF THE INVENTION In order to solve this drawback, the present invention is to reduce the construction cost of a reverse osmosis desalination apparatus for seawater as much as possible. Reduce idle periods throughout the year by creating a structure that allows the equipment to be used effectively at all times, even in times of drought. To improve capital investment efficiency by reducing equipment that may be idle for a long period of time, such as a secular storage dam as a measure against abnormal drought and a dedicated reverse osmosis desalination device for seawater. The total utilization of late-night electricity at seawater pumped-storage power plants and effective power recovery of concentrated seawater residual pressure can be effectively combined to reduce the cost of desalination for seawater desalination, and to reduce the water quality of tap water generated in recent years due to the deterioration of raw water quality. The challenge was to improve the mold odor and taste and the generation of carcinogens such as trihalomethane, and to replace the existing water supply, which suffers from a sharp rise in the cost of clean water treatment by large amounts of activated carbon and chemicals.

[0004]

In order to achieve the above object, the present invention uses seawater reverse osmosis desalination equipment and equipment of a seawater pumped storage power plant in common so that most of the construction cost and operation and maintenance costs are seawater pumped power generation. Share with the office. Therefore, most of the equipment is operated as a seawater pumped-storage power station at all times, and all or part of the seawater required for power generation at the seawater pumped-storage power station is supplied to the seawater reverse osmosis desalination plant only during an abnormal drought. Reduce idle equipment other than time. In addition, in the case of long-term abnormal drought, in order to reverse osmosis desalination of the total amount of seawater in the seawater reservoir, the nighttime electricity is pumped up to the amount of seawater required for desalination in the daytime, and the nighttime electricity is used for 24 hours to generate the desalination power source. It is also possible to reduce the unit price and increase the supply of fresh water.

[0005]

According to the present invention, the reverse osmosis desalination apparatus for power generation is used as a source of reverse osmosis desalination at the time of abnormal drought by sharing the seawater reverse osmosis desalination apparatus and the equipment of the seawater pumping power plant. Can be used as is as seawater. Among the facilities of the seawater pumped storage power plant, seawater intake pipe, dust remover, water pipe, high pressure pump,
Most of the seawater pumped-storage power generation equipment such as generators, electric motors, pressure transmission and return pipes, seawater reservoirs, high-pressure water turbines, and drainage pipes can be used for reverse osmosis desalination of seawater. It is also possible to recover the pressure as electric power and use it for peak load power. Therefore, it is operated as a seawater pumped-storage power plant at all times, and as a special facility for adding reverse osmosis desalination of seawater only during an abnormal drought period, in the embodiment of FIG.
Only the module unit of reverse osmosis membrane, clean water tank, etc. are required, and in the embodiment of FIG. 2, a high pressure pump, a high pressure water turbine, an electric motor, a generator, and a pressure return pipe can be omitted. In addition, the quality of reverse osmosis water of seawater is almost the same, and it satisfies the water quality standards of the Waterworks Law. It can be used only by simple post-treatment such as pH adjustment and hardness treatment, and it also causes cancer such as mold odor and trihalomethane. Since it does not contain any substances and does not require advanced treatment such as activated carbon input, it can be used for water supply entirely if the unit price of electricity for desalination approaches the unit price of electricity for existing waterworks.
Furthermore, its construction period is also a suitable T. P + 500m
If you use a high-grade mountain, you can construct it in a much shorter period of time at a lower cost and avoid environmental problems, measures against submerged residents, etc.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention; FIG. 1 shows a flow sheet of a seawater reverse osmosis desalination apparatus that shares equipment with a seawater pumped storage power plant according to an embodiment of the present invention. In FIG. 1, the arrow → indicates the direction of the flow of seawater or fresh water, and the arrow ← → indicates that the flow reciprocates. This will be explained in the order of flow with a flow sheet. For the operation of the rectifying device, first of all, T. Seawater is pumped up to the seawater storage pond (1) installed on the summit of P + 500m class, but the amount of water is assumed to be 460,000 tons per day, which is 10% (average). In the case of supplying water to a city that can prevent nighttime water outages), if the permeation recovery rate of the seawater reverse osmosis membrane is 40% (460,000 tons x 0.1 / 0.4), approximately 1
20,000 tons of seawater is required, and if the scale of the seawater reservoir (1) is expressed numerically, length 100m x width 60m x depth 20
If the reverse osmosis desalination system is fully operated day and night, it will always be pumped and reverse osmosis desalinated, so half the size will be 60m x width 50m x depth 20m, about 60,000 tons is sufficient. Is. This seawater is filtered by a sand filter (2) at the summit in the daytime, and then pressure-fed by a pressure return pipe (4), and 40 times of seawater is fed by a module unit (7) of the reverse osmosis membrane at the foot of the mountain.
% Of the water is reverse osmosis desalinated and stored in the clean water tank (11), and the residual pressure of seawater concentrated to 60% in the module unit (7) is directly connected to the high-pressure turbine (8). Is used to generate peak daytime load power, but even in this case approximately 60% of the seawater used for reverse osmosis desalination can be generated, and then the residual pressure is recovered by the high pressure turbine (8). The concentrated seawater thus obtained is depressurized to atmospheric pressure and finally discharged and diffused from the drain pipe (12) to the near sea (14). To pump seawater into the seawater reservoir (1) at night (1)
The clear offshore seawater of 4) is collected by the water pipe (15) and removed by the dust remover (13) and supplied to the high pressure pump (5) by the water delivery pipe (10) to operate the electric motor (6) at midnight power. Water is pumped from the pressure return pipe (3) to the seawater reservoir (1). If the abnormal drought period is overcome in this way, then this equipment will use the surplus power at night as a normal seawater pumped-storage power plant to pump seawater to the seawater reservoir (1) to prepare for peak power during the daytime. All can be used for power generation. As described above, when this equipment is operated as a normal seawater pumped-storage power station except when there is an abnormal drought, it is a dedicated equipment for reverse osmosis desalination of seawater. Sand filter (2) Pressure return pipe (4) Module unit (7 ) The tap water tank (11) is shut off by each attached valve, and the electric motor (6) is driven by midnight power during the night to pump seawater into the seawater reservoir (1) using the high-pressure pump (5). And store. In the daytime, this seawater flows down from the pressure transmission / return water pipe (3) in the opposite direction of the nighttime, and the high-pressure turbine (8) drives the generator (9) to generate electric power to replenish the peak daytime load power. In the above example, the seawater pumped-storage power plant owned by the existing local electric power company is attached with a reverse osmosis desalination device for seawater, and only a part of the capacity of the seawater pumped-storage power plant is observed only once during an abnormal drought. Or it is a method of operating the reverse osmosis desalination equipment of seawater by borrowing the whole waterworks of each municipality. In that case, the amount of power generated during the daytime peak load is 60% of the normal power, so 40% of the power is consumed. The shortage must be replenished by electric power companies in other prefectures using power lines. The flow sheet embodiment of FIG. 2 further simplifies the structure of the present invention and omits the pressure return pipe (4) in the embodiment of FIG. 1 to reduce the construction cost, the high pressure pump (5) and the electric motor (6). ) And a high-pressure water turbine (8) and a generator (9) as shown in FIG.
6) and a high-pressure pump turbine (17) are combined, and a dedicated seawater reverse osmosis desalination device is very simple, and a high-pressure sand filter device (18) and a module unit (7) are slightly used. And only the water tank (11). In addition, the point different from the embodiment of FIG. 1 is that a high pressure sand filter for removing dirt from the inside of the pressure water return pipe (3) used instead of omitting the pressure water return pipe (4) and raw seawater ( 18) was brought from the summit to just before the module unit (7) at the foot of the mountain, so it had a pressure-resistant structure of about 50 kg / cm ² , and in the high-pressure pump turbine (17) that doubles as a pump and turbine, seawater is pumped and power is generated. However, the 24-hour desalination operation of the embodiment of FIG. 1 cannot be performed at the same time, but another feature of the embodiment of FIG. 2 is that when the seawater reverse osmosis desalination device is incorporated in the seawater pumped-storage power plant. The function and structure of the seawater pumped-storage power plant, whether the existing seawater-pumped-storage power plant is remodeled or attached to the new seawater-pumped power plant because only one bypass pipe is required for the pressure water return pipe (3). Construction is easy without damaging Now, the operation of the seawater reverse osmosis desalination system will be simplified. However, while it is up to the local government to decide whether the main body of operation and maintenance of equipment is the electric power company or the water department, most of the equipment is seawater pumped-storage power generation equipment, and it is not possible to operate it as a reverse osmosis desalination equipment for seawater. In view of the fact that there is only one opportunity every year, it is a good idea to invest the equipment dedicated to reverse osmosis desalination at the Waterworks Bureau, and to operate and maintain it in the form of a private contract with an electric power company. Furthermore, if the water quality of the water supply deteriorates and the cost of clean water treatment continues to rise, the power company will independently build a seawater pumped-storage power plant dedicated to reverse osmosis desalination of seawater, and will use its own late-night surplus electricity to provide good quality at low cost. Water can be sold to the water department, but there is also a method of constructing and operating as a seawater pumped-storage power station and reverse osmosis desalination facility in a third sector between the electric power company and the local government.

[0007]

As described above, according to the present invention, most of the construction cost can be reduced by using the reverse osmosis desalination facility for seawater utilizing the high head water pressure from the seawater reservoir on the mountain and the facility of the seawater pumped storage power plant. It has the effect of sharing the share with the pumped storage power plant to save energy. If the reverse osmosis desalination device desalinates all or part of the seawater in the mountaintop seawater storage pond that was pumped up for power generation at the seawater pumped-storage power plant, only when there is an abnormal drought once every several years. Since the original equipment can be operated as a seawater pumped-storage power plant, most of the equipment can be effectively used to reduce idle periods. When a part or all of seawater is desalinated by reverse osmosis desalination equipment during abnormal drought, the lack of 40% of the power generation capacity during that period can be assisted by electric power companies in other prefectures through transmission lines, such as water pipes. Even if the direct water supply assistance from other neighboring prefecture waterworks is not received, the result is the same as receiving water from a remote place through a transmission line. When reverse osmosis desalination of the entire amount of seawater in a seawater storage pond is carried out during a long-term abnormal drought as in the embodiment of Fig. 1, nighttime electricity can be obtained by pumping a sufficient amount of seawater necessary for desalination in the daytime. It is the same as using 24 hours a day, and there is an effect that all electricity can be operated at the unit price of midnight power, and if it is limited to 3 hours from 1:00 pm to 4:00 pm at the peak of daytime, by creating water in the next 21 hours It is also possible to combine power generation and desalination. In the embodiment shown in FIG. 2, the high pressure pump and the high pressure water turbine can be used as one unit, and the pressure return pipe can be omitted from the summit where the construction cost is high and the head is 500 m. It has the effect of significantly reducing the construction cost and construction period. As a measure against the deterioration of the quality of raw water in recent years, if the present invention can significantly reduce the unit price of electricity for reverse osmosis desalination of seawater, even if the cost of water purification treatment such as the input of deodorizing powdered activated carbon used during water purification is high. , The quality of seawater reverse osmosis water is sufficiently close to the water quality standard of the Waterworks Law, so only a small amount of post-treatment is required.
Reverse osmosis water of seawater is replaced with tap water as a measure to prevent contamination of the tap water carcinogen trihalomethane, which is generated in the future with excessive chlorine injection, because deodorization treatment with powdered activated carbon is not required and chlorine injection is small. There is also the possibility of an effect that can be achieved. The concept of a long-term storage dam, which is always considered as another measure during abnormal drought, also requires huge construction costs, and there are many problems such as environmental destruction and measures to protect residents in submerged areas. When it is not present, the present invention has the effect of improving the investment efficiency in all aspects because it becomes a completely idle facility. In the actual construction and operation, if the electric power company and the local government jointly invest in the construction and operation of the seawater pumped storage power plant that shares the seawater reverse osmosis equipment,
There is also an effect that the peak load power can be sold to the electric power company at all times, and fresh water can be produced only when there is an abnormal drought and sold to the municipal water supply.

[Brief description of drawings]

FIG. 1 is a flowchart of an embodiment in which a high-pressure pump and a high-pressure turbine of a seawater reverse osmosis device are separately provided.

FIG. 2 is a flowchart of an example in which a high-pressure pump turbine is used in a seawater reverse osmosis device.

[Explanation of symbols]

 (1) Seawater reservoir (2) Sand filter (3) Pressure water return pipe (4) Pressure water return pipe (5) High pressure pump (6) Electric motor (7) Module unit (8) High pressure water turbine (9) Generator ( 10) Water pipe (11) Water tank (12) Drain pipe (13) Dust remover (14) Near sea (15) Water intake pipe (16) Generator motor (17) High-pressure pump turbine (18) High-pressure sand filter

Claims (3)

[Claims] 1. A midnight surplus power is used to reverse osmosis desalinate seawater with a high-pressure pump, and the residual pressure of concentrated seawater is recovered as electric power with a high-pressure turbine and a generator, and at the same time pumped to a seawater reservoir on a mountain. In the daytime, the seawater in the seawater storage pond is reverse osmosis desalinated at a high head water pressure, and the residual pressure of concentrated seawater is recovered as electric power by a high-pressure turbine and a generator to use the late night surplus power for 24 hours. 2. A high-pressure pump turbine to which seawater is pumped to a seawater reservoir on a mountain by a high-pressure pump turbine directly connected to the generator-motor, the seawater is reverse osmosis desalinated by the high head water pressure, and the residual pressure of concentrated seawater is generated by the same high-pressure pump turbine. Method to drive electricity to recover electric power. 3. The reverse osmosis of seawater shared with the seawater pumped-storage power plant so that the equipment can be operated as a reverse osmosis desalination device during abnormal drought, and can be operated as a normal seawater pumped-storage power plant at other times. Desalination method.