JP2013192971A - Power recovery bwro system, and power recovery method - Google Patents

Abstract

A low-cost and highly reliable power recovery BWRO system and power recovery method are provided.
High pressure concentrated salt water discharged from a BWRO membrane 5 for filtering salt water pumped by a high pressure pump 4 is injected into a small area chamber 612 of a different area cylinder pump 6 y of a piston power recovery device 6, From the salt water tank 1 installed in a high place in the chamber 611 on the area side, the salt water pumped and injected by gravity instead of the water injection pump is pushed out toward the high pressure pump 4, while the salt water is put into the chamber 613 on the large area side. Salt water is injected from the tank 1, and the concentrated salt water stored in the chamber 614 on the small area side of the cylinder pump 6x is discharged to recover power.
[Selection] Figure 1

Description

  Embodiments of the present invention relate to a power recovery BWRO system and a power recovery method using a reverse osmosis membrane such as seawater desalination.

  Many BWRO (Brackish Water Reverse Osmosis) systems recycle salt water by reusing the energy of high salinity and high-pressure concentrated salt water discharged from the remaining osmosis membrane from desalinated seawater. The power is recovered. Up to now, there has been devised a system that uses a power feedback configuration in which a different-area piston type power recovery device as shown in FIG. 7 is provided and the power of concentrated salt water is converted to water supply power using the principle of a hydraulic cylinder ( For example, Patent Document 1).

  However, these power recovery BWRO systems require pressure-resistant piping with high initial cost of the power recovery device because the water supply is high-pressure salt water, the cost reduction effect is relatively small, and the number of devices increases, so reliability There was a problem of lowering.

JP 2011-56439 A

  The conventional power recovery BWRO system requires pressure resistant piping with high initial cost of the power recovery device because the water supply is high-pressure salt water, the cost reduction effect is relatively small, and the reliability is low because the number of devices increases. There was a problem.

  The problem to be solved by the present invention is to provide a power recovery BWRO system and a power recovery method with low cost and high reliability.

  In order to achieve the above object, the power recovery BWRO system of the present embodiment is configured to recover the concentrated salt water discharged from the high pressure obtained by desalinating the salt water pumped by the high pressure pump through the BWRO membrane, and the piston power recovery by the different area cylinder pump. In a power recovery BWRO system that recovers power by injecting into a means, a salt water tank installed at a high place for sending out the stored salt water at a water pressure for pouring water into the piston power recovery device, and salt water sent from the salt water tank A first switching valve that is injected with water and switches its destination to either the first or second, and the concentrated salt water is injected, and the destination is switched to either the first or the second. 2 and a position detecting means for notifying that the position of the piston has reached the moving end, and the connection destination of the output valve of the large area cylinder side chamber is Connected to the input side of the pressure pump, the input valve is connected to the first delivery destination of the first switching valve, the output valve of the cylinder-side chamber on the small area side is connected to the discharge destination, and the input valve is A first different area cylinder pump connected to the first delivery destination of the second switching valve, and position detecting means for notifying that the position of the piston has reached the moving end; The destination of the output valve is connected to the input side of the high-pressure pump, the input valve is connected to the second destination of the first switching valve, and the output valve of the cylinder-side chamber on the small area side goes to the outlet. A second different area cylinder pump connected to a second delivery destination of the second switching valve, and a large cylinder side of the first different area cylinder pump as a first cycle. Salt from the salt water tank into the chamber And by controlling the delivery destination of the first and second switching valves so as to inject the high-concentration salt water into the small area chamber of the second cylinder pump. When each piston is moved and the position detection means is notified that both pistons have reached the moving end, the sending destination of both switching valves is switched to the other cylinder pump to reverse the moving direction of each piston. And a control means for performing control in which the water supply / drainage in each chamber of both pumps is a second cycle that is reverse to the first cycle.

  Moreover, the power recovery method of the power recovery BWRO system of this embodiment includes a salt water tank, a switching valve, a different area cylinder pump, and a control means, and salt water pumped by a high pressure pump is desalinated through a BWRO membrane. In the power recovery method of the power recovery BWRO system that recovers power by injecting the remaining concentrated salt water discharged at high pressure into a piston power recovery device using a different area cylinder pump, the salt water tank collects the stored salt water into the piston power recovery The first switching valve, which is installed at a high place where water is pumped to the apparatus and switches the destination to any one of the two destinations, is injected with salt water sent from the salt water tank. The second switching valve for switching to any one of the two is injected with the concentrated salt water, and the first and second different area cylinder pumps are Each has a position detection means for notifying that the position of the piston has reached the moving end, and the connection destinations of the output valves of the large area cylinder side chamber are both connected to the input side of the high pressure pump, and the input valve is the first valve. The switching valve is connected to each delivery destination, the output valves of the chambers on the small area cylinder side are both connected to the discharge destination, the input valve is connected to each delivery destination of the second switching valve, and the control means As a first cycle, the salt water from the salt water tank is injected into the large area cylinder side chamber of the first different area cylinder pump, and the high pressure concentrated salt water is injected into the small area side chamber of the second cylinder pump. Controlling the delivery destination of the first and second switching valves so as to inject, moving each piston by pressing the injected water, and confirming that both pistons have reached the moving end When notified from the position detecting means, the delivery destination of the two switching valves is switched to the other cylinder pump, the direction of movement of each piston is reversed, and the water supply / drainage in each chamber of both pumps is reversed with respect to the first cycle. The second cycle is controlled.

The lineblock diagram showing the composition of the power recovery BWRO system concerning this embodiment. The functional block diagram explaining the operation | movement procedure at the time of starting start (1st step) of the power recovery BWRO system of this embodiment. The functional block diagram explaining the operation | movement procedure at the time of the 2nd step of the power recovery BWRO system of this embodiment. The functional block diagram explaining the operation | movement procedure at the time of the 3rd step of the motive power collection | recovery BWRO system of this embodiment. The functional block diagram explaining the operation | movement procedure at the time of the 4th step of the motive power collection | recovery BWRO system of this embodiment. The functional block diagram explaining the operation | movement procedure at the time of the 5th step of the power recovery BWRO system of this embodiment. Conventional power recovery BWRO system diagram. The basic block diagram of the conventional BWRO system which does not perform power recovery.

  A power recovery BWRO (Brackish Water Reverse Osmosis) system according to an embodiment will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing a configuration of a power recovery BWRO system according to the present embodiment.
In FIG. 1, the power recovery BWRO system of the present embodiment includes a salt water tank 1 for storing salt water, a salt water flow regulating valve 7 for adjusting and discharging a salt water flow rate from the salt water tank 1, and a suction of the discharged salt water. Piston power recovery device 6 that pumps out, safety filter 3 that passes the pumped salt water, high-pressure pump 4 that takes in salt water that has passed through the safety filter 3 and pumps it at a high pressure of about 20 atmospheres, and filters the pumped salt water A BWRO membrane 5 that discharges fresh water and concentrated salt water, a concentrated salt water flow control valve 8, and a bypass valve 11 are provided.

  The salt water tank 1 is installed at a height Z such as a tower and a building roof, and a large amount of salt water such as seawater to be desalinated is pumped by a pump not shown and stored. The salt water sent out from the salt water tank 1 is discharged using the potential energy of height Z instead of the conventional water pump 2 shown by the dotted line, and is injected into the piston power recovery device 6 through the salt water flow regulating valve 7. The

  The piston power recovery device 6 includes two cylinder pumps 6x and 6y inside, a position sensor 6s for detecting that each cylinder position has reached the end, a switching valve 60, a switching valve 69, and a position sensor. Based on the cylinder detection information from 6 s, a switching valve 69 and a controller 61 for controlling the four position sensors 6 s indicated by “升” -type symbol marks are provided. There are various types of position sensors 6s, and mechanical switches, magnetic sensors, optical sensors, or the like may be used as long as they detect the piston position.

  The cylinder pumps 6x and 6y have cylinder chambers (hereinafter referred to as chambers) 613 and 614 and chambers 611 and 612, respectively. The cylinder area A3 of the chambers 611 and 613 is greater than the cylinder area A2 of the chambers 612 and 614. It is a large different area cylinder pump.

  In the chambers 611 and 613, the salt water from the salt water flow control valve 7 is switched to one by the switching valve 60 and injected into the input valve i. The output valves o of the chambers 611 and 613 are connected to the safety filter 3 and the bypass valve 11 by piping. Similarly, in the chambers 612 and 614, the concentrated salt water from the BWRO membrane 5 is switched to one by the switching valve 69 and injected into the input valve i. The output valves o of the chambers 612 and 614 are connected to the concentrated salt water flow control valve 8 by piping. In addition, although not shown in figure, the check valve is provided in the input and output piping to each of these chambers.

  The bypass valve 11 may be omitted because it is used only for bypassing the safety filter 3 and allowing salt water to flow to the high-pressure pump 4 until salt water fills the piping system when the power recovery BWRO system is started.

FIG. 7 is a system diagram shown in Japanese Patent Application Laid-Open No. 2011-56439, which is a conventional power recovery BWRO system.
Conventionally, salt water is supplied to the safety filter 30 and the high-pressure pump 40 by the water supply pump 20, but in the present embodiment of FIG. 1, the water supply pump 20 is omitted, so the number of components is small and there is a failure. Can be kept low. In the different area cylinder pump of the system shown in FIG. 7, the concentrated salt water from the BWRO membrane 5 is injected into the large area cylinder side, and the water supply whose pressure is converted from the small area cylinder to the high pressure is output from the high pressure pump 40. The point injected to the side has an opposite relationship to the present embodiment.

  In this embodiment, it is the same as using this example and the pressure of concentrated salt water, but the mechanical stress is reduced by converting the salt water pumped from the cylinder pump into a low pressure on the input side of the high pressure pump. This reduces the number of components and increases the reliability because the water pump is omitted.

Below, with reference to FIGS. 2-6, the operation | movement procedure of the power recovery BWRO system of this embodiment is demonstrated.
FIG. 2 is a functional block diagram for explaining an operation procedure at the time of initial setting (startup) of the power recovery BWRO system of the present embodiment, and FIGS. 3 to 6 are operation procedures in each cycle of the power recovery BWRO system of the present embodiment. It is a functional block diagram explaining these.
In FIG. 2, at the initial setting (start-up) which is the first step of the system operation, when salt water is injected from the salt water tank 1 for the first time, the controller 61 opens the switching valve 60 on the chamber 611 side and closes the chamber 613 side. . The switching valve 69 is closed on the chamber 612 side and opened on the chamber 614 side. Here, in FIGS. 2 to 6, the state in which the switching valves 60 and 69 are painted out represents a closed state, and the white state represents an open state.

  Moreover, the thick line display part of piping corresponds to the part through which salt water and concentrated salt water flow. (The following steps are also the same.) Then, salt water is poured into the chamber 611 using the water pressure of the salt water tank 1, and the chamber 611 and the chamber 614 are filled via the bypass line 11, the high pressure pump 4, and the BWRO membrane 5. It flows in until it becomes. As a result, as shown in FIG. 3, the position sensor 6 s that detects that both cylinders have reached the ends of the chamber 612 and the chamber 613 transmits a position detection signal to the controller 61.

  As a second step, the controller 61 receives this position detection signal, and performs control for switching the inflow directions of the switching valve 69 and the switching valve 60 following the timing when the cylinders are aligned and reach the ends of the chamber 612 and the chamber 613. Do. That is, as shown in FIG. 3, the switching valve 60 is closed on the chamber 611 side and opened on the chamber 613 side. The switching valve 69 is opened on the chamber 612 side and closed on the chamber 614 side. Since the piping path and the chambers 611 and 614 are in the first cycle state, the valve of the bypass line 11 is subsequently closed.

  As shown in FIG. 4, in the third step, the high pressure pump 4 is activated to boost the salt water and output it to the BWRO membrane 5. The pressure P1 after the pressure increase is usually about 10 to 15 bar, although it varies depending on the salt concentration of the salt water and the type of the BWRO film. The BWRO membrane 5 filters the supplied salt water and sets the recovery rate to y%, so that y% fresh water and (100-y)% concentrated salt water that has flowed in are discharged from the BWRO membrane 5, respectively. .

  At this time, the fresh water pressure P4 is about 0.2 bar, for example, due to the pressure loss of the BWRO membrane, but the concentrated salt water pressure P2 is about 85% (8 to 12 bar) of P1. The high-pressure concentrated salt water flows into the chamber 612 and pushes the piston to push out the salt water in the chamber 611 toward the safety filter 3.

  On the other hand, salt water flows into the chamber 613 from the salt water tank 1 and the concentrated salt water in the chamber 614 is discharged by the pressure pushing the piston, and is discharged from the concentrated salt water flow control valve 8.

  As shown in FIG. 5, the third step ends when both pistons hit the walls of the chamber 611 and the chamber 614, and the controller 61 opens the switching valve 60 on the chamber 611 side and closes the chamber 613 side as a fourth step. Then, the switching valve 69 is closed on the chamber 612 side and the chamber 614 side is opened to control the direction of the salt water flow.

  Subsequently, as a fifth step, as shown in FIG. 6, the high-pressure concentrated salt water flowing into the chamber 614 now pushes the piston to push out the salt water in the chamber 613 toward the security filter 3. On the other hand, salt water is flowed from the salt water tank 1 to the chamber 611 and the concentrated salt water in the chamber 612 is discharged. As a result, in the same manner as in FIG. 3, when the pistons reach the ends of the chamber 612 and the chamber 613, the same state as step 2 is obtained, and one operation cycle is completed. Thereafter, the second to fifth steps are performed. repeat.

  FIG. 8 is a basic configuration diagram of a conventional BWRO system that does not perform power recovery.

  In FIG. 8, the water pump 2 is used in addition to the high-pressure pump 40. As one trial calculation example, a system for desalinating 100 tons of salt water at a membrane recovery rate of 80%, the membrane filtration pressure is 13.26 bar and the concentration is increased. If the salt water pressure is 13.06 bar and the efficiency of each pump is 80%, both pumps will have a water pump of 0.28 KW and a high pressure pump of 1.68 KW for a total of about 1.96 KW.

  In contrast, in this embodiment, when the cylinder pumps 6x and 6y having a cylinder area ratio for power recovery of 5: 1 are used without using the water pump 2, the pressure of the concentrated salt water from the high-pressure pump 4 is used. Thus, water can be supplied to the high pressure pump 4 without using a water pump, and the power of the high pressure pump 4 can be 1.59 KW.

  In the power recovery method described in Japanese Patent Application Laid-Open No. 2011-56439 in FIG. 7, the high-pressure salt water is input to the output side of the high-pressure pump using the power recovery pump. On the other hand, in this embodiment, low-pressure salt water is input to the high-pressure pump 4 to operate with a reduced pressure stress on equipment such as piping, and the water pump is omitted to reduce the number of devices, thereby achieving high reliability. It is possible to provide a power recovery BWRO system and a power recovery method with low operating costs.

  According to the power recovery BWRO system of at least one embodiment described above, the water pump to the high-pressure pump is omitted, and high-pressure concentrated brine is injected into the small-area chamber of the different-area cylinder pump to increase the large-area side. It is possible to achieve high reliability by extruding the salt water injected into the chamber and feeding it to the high pressure pump and recovering the power of the high pressure pump output.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1 Salt Water Tank 3 Safety Filter 4 High Pressure Pump 5 BWRO Membrane 6 Piston Power Recovery Device 6x, 6y Cylinder Pump 6s Position Sensor 60, 69 Switching Valve 61 Controller 7 Salt Water Flow Control 8 Concentrated Salt Water Flow Control 11 Bypass Valve

Claims (2)

In the power recovery BWRO system for recovering power by injecting salt water pumped by a high pressure pump into the piston power recovery means by a different area cylinder pump, the remaining concentrated high pressure water that has been desalinated through the BWRO membrane is discharged.
A salt water tank installed at a high place for sending out the stored salt water at a water pressure for pouring water into the piston power recovery device;
A first switching valve for pouring salt water sent out from the salt water tank and switching its destination to either one of the first or second;
A second switching valve for injecting the concentrated salt water and switching its destination to either the first or the second;
Position detecting means for notifying that the position of the piston has reached the moving end is provided, the connection destination of the output valve of the large area cylinder side chamber is connected to the input side of the high pressure pump, and the input valve is connected to the first switching The first valve is connected to the first destination of the valve, the output valve of the cylinder chamber on the small area side is connected to the outlet, and the input valve is connected to the first destination of the second switching valve. Different area cylinder pump,
Position detecting means for notifying that the position of the piston has reached the moving end is provided, the connection destination of the output valve of the large area cylinder side chamber is connected to the input side of the high pressure pump, and the input valve is connected to the first switching The second valve connected to the second destination of the valve, the output valve of the cylinder chamber on the small area side is connected to the outlet, and the input valve is connected to the second destination of the second switching valve. Different area cylinder pump,
As a first cycle, salt water from the salt water tank is injected into the large area cylinder side chamber of the first different area cylinder pump, and high pressure concentrated salt water is injected into the small area side chamber of the second cylinder pump. In the same manner, the destinations of the first and second switching valves are controlled to move the respective pistons by pressing the injected water, and the position detecting means is notified that both the pistons have reached the moving end. In this case, the delivery destination of the both switching valves is switched to the other cylinder pump to reverse the moving direction of each piston, so that the water supply / drainage in each chamber of both pumps is the second cycle that is reverse to the first cycle. A power recovery BWRO system comprising control means for performing control. A salt water tank, a switching valve, a different area cylinder pump, and a control means, and the salt water pumped by the high pressure pump is desalinated through the BWRO membrane. In the power recovery method of the power recovery BWRO system that recovers power by injecting into the recovery device,
The salt water tank is installed at a high place where the stored salt water is sent out at a water pressure for pouring water into the piston power recovery device,
The first switching valve that switches the delivery destination to any one of the two destinations is filled with salt water delivered from the salt water tank,
The second switching valve that switches the destination to any one of the two destinations is injected with the concentrated salt water,
Each of the first and second different area cylinder pumps is provided with position detecting means for notifying that the position of the piston has reached the moving end, and the connection destination of the output valve of the large area cylinder side chamber is both the high pressure pump The input valve is connected to each delivery destination of the first switching valve, the output valves of the chambers on the small area cylinder side are both connected to the discharge destination, and the input valves are connected to the second destination. Connected to each destination of the switching valve,
The control means includes
As a first cycle, salt water from the salt water tank is injected into the large area cylinder side chamber of the first different area cylinder pump, and high pressure concentrated salt water is injected into the small area side chamber of the second cylinder pump. In the same manner, the destination of the first and second switching valves is controlled to move each piston by pressing the injected water,
When it is notified from the position detection means that both the pistons have reached the moving end, the delivery destination of the both switching valves is switched to the other cylinder pump to reverse the direction of movement of each piston, and each chamber of both pumps The power recovery method of the power recovery BWRO system is characterized in that the control is performed so that the water supply / drainage in the second cycle is the reverse of the first cycle.

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