JP5703209B2 - Energy recovery chamber - Google Patents

Description

  The present invention relates to a seawater desalination system that removes salt from seawater to desalinate seawater and an energy recovery chamber that is suitably used in the seawater desalination system (seawater desalination plant).

  Conventionally, as a system for desalinating seawater, a seawater desalination system is known in which seawater is passed through a reverse osmosis membrane separator and desalted. In this seawater desalination system, the collected seawater is adjusted to a constant water quality condition by a pretreatment device, and then pressurized by a high-pressure pump and pumped to a reverse osmosis membrane separation device. A part of the high-pressure seawater is taken out as fresh water from which the salt content has been removed by overcoming the reverse osmosis pressure and passing through the reverse osmosis membrane. The other seawater is discharged as reject (concentrated seawater) from the reverse osmosis membrane separation device in a state where the salinity is increased and concentrated. Here, the maximum operating cost (electric power cost) in the seawater desalination system greatly depends on the energy for raising the pretreated seawater to a pressure that can overcome the osmotic pressure, that is, the reverse osmotic pressure, that is, the pressurized energy by the high-pressure pump. To do.

  That is, more than half of the power cost, which is the maximum operation cost in the seawater desalination system, is often spent for pressurization by the high-pressure pump. Therefore, the pressure energy possessed by the high salinity and high pressure reject (concentrated seawater) discharged from the reverse osmosis membrane separator is used as energy for boosting a part of the seawater. Then, as a means for using the pressure energy of the concentrated seawater discharged from the reverse osmosis membrane separation device as energy for boosting a part of the seawater, the inside of the cylinder is circulated by a piston movably fitted in the cylinder. An energy recovery chamber is used, which is divided into two volume chambers and provided with a concentrated seawater port for entering and exiting concentrated seawater in one of the two separated spaces and a seawater port for entering and exiting seawater at the other. ing.

  FIG. 13 is a schematic diagram illustrating a configuration example of a conventional seawater desalination system (for example, Patent Document 1). As shown in FIG. 13, seawater taken by a water intake pump (not shown) is pretreated by a pretreatment device and adjusted to a predetermined water quality condition, and then a motor M is directly connected via a seawater supply line 1. Supplied to the high-pressure pump 2. Seawater pressurized by the high-pressure pump 2 is supplied via a discharge line 3 to a reverse osmosis membrane separator 4 equipped with a reverse osmosis membrane (RO membrane). The reverse osmosis membrane separation device 4 obtains fresh water from seawater by separating seawater into concentrated seawater having a high salinity concentration and fresh water having a low salinity concentration. At this time, concentrated seawater with a high salinity is discharged from the reverse osmosis membrane separation device 4, but this concentrated seawater still has a high pressure. A concentrated seawater line 5 for discharging concentrated seawater from the reverse osmosis membrane separation device 4 is connected to a concentrated seawater port P1 of the energy recovery chamber 10 via a control valve 6. A seawater supply line 1 for supplying pre-processed low-pressure seawater branches upstream of the high-pressure pump 2 and is connected to a seawater port P2 of the energy recovery chamber 10 via a valve 7. The energy recovery chamber 10 includes a piston 12 therein, and the piston 12 is fitted so as to be movable while separating the inside of the energy recovery chamber 10 into two volume chambers.

  Seawater that has been pressurized using the pressure of concentrated seawater in the energy recovery chamber 10 is supplied to the booster pump 8 via the valve 7. Then, the booster pump 8 further increases the pressure of the seawater so that the pressure becomes the same level as the discharge line 3 of the high-pressure pump 2, and the pressurized seawater merges with the discharge line 3 of the high-pressure pump 2 via the valve 9 and reverses. The osmotic membrane separation device 4 is supplied.

JP 2009-243368 A

  In the energy recovery chamber described above, high-pressure concentrated seawater flows into the chamber and pressurizes the seawater in the chamber. The internal pressure of the chamber is low when sucking seawater, and high when pushing seawater with concentrated seawater. That is, since the internal pressure of the chamber repeats a high pressure and a low pressure, the chamber usually uses a metal such as stainless steel. Of the stainless steels, a stainless steel with excellent seawater resistance called duplex stainless steel is often used in consideration of seawater corrosion.

  The present inventors have obtained the following knowledge in the process of considering the use of fiber reinforced plastic (FRP) in order to reduce the cost, reduce the weight, and improve the inner diameter accuracy of the energy recovery chamber.

The general idea is that fiber reinforced plastic (FRP) is not suitable for repeated pressure fluctuations. This is because cracks are likely to occur in each layer that is laminated due to repeated stress fluctuations, and once a crack has occurred, there is a concern that a fault may occur and leakage may occur. Further, when the fibers are woven, the fibers are contained at an angle that reinforces the circumferential direction. When internal pressure is applied to a container made of FRP, there is little expansion and contraction in the circumferential direction, but expansion and contraction in the axial direction.
When manufacturing an energy recovery chamber using a glass fiber reinforced plastic that is a typical FRP, glass fiber is impregnated with molten resin as shown in FIG. 14, and a glass fiber is obliquely inclined at an angle α in a cylindrical mold called a mandrel. Then, the glass fiber is wound in the opposite direction so as to be folded back, whereby the layers in the fiber direction at the angle α are alternately laminated. At this time, since the angle α with respect to the axis is wound at an angle of about 55 degrees, the circumferential component is larger than the axial component and the strength is given to the circumferential direction, so that the structure is relatively weak in the axial direction. It has become.

The concentrated seawater of the seawater desalination system using the RO membrane has a high pressure of 6 to 7 MPa, and in the case of the energy recovery chamber, the pressure fluctuation from a low pressure of 0.1 MPa to a high pressure of 6 to 7 MPa is frequently repeated. . Normally, the energy recovery chamber is used under conditions where it undergoes repeated pressure fluctuations several million times a year.
More specifically, for example, when the pressure of seawater at the RO membrane inlet is 6.5 MPa, the concentrated seawater is discharged at a pressure of about 6.4 MPa, which is slightly reduced due to the pressure loss of the RO membrane module. The concentrated seawater of 6.4 MPa is transmitted to the seawater in the energy recovery device, but since there is a slight pressure loss when passing through the energy recovery device, 6.3 MPa of seawater is discharged from the energy recovery device. Since the 6.3 MPa seawater discharged from the energy recovery device is boosted to the RO membrane inlet pressure 6.5 MPa and merged with the seawater from the high pressure pump, the booster pump boosts the inlet pressure 6.3 MPa to 6.5 MPa. . This pressure value is an example, but a small pressure loss of the RO membrane, piping, and energy recovery device is compensated by a booster pump and merged with the high pressure pump.
When manufacturing an energy recovery chamber made of FRP, flanges and end plates that respectively close the openings at both ends of the cylindrical chamber body made of FRP are provided, and these flanges and end plates are fixed to both ends of the chamber body. There is a need. In this case, a method may be considered in which stud bolts are embedded at both ends of the FRP chamber body, the openings at both ends are closed with flanges, and nuts are screwed onto the stud bolts to fix the flanges to both ends of the chamber body. . Another possible method is to provide end plates at both ends of the FRP chamber main body and fix these end plates to the chamber main body using fasteners called shear keys.

However, even if the flange or end plate is fixed to the FRP chamber body using any method, a load obtained by multiplying the chamber cross-sectional area by the chamber internal pressure is applied to the flange or end plate, and the load is applied to the stud bolt or shear key. Take it. The load acts as a tensile load in the axial direction of the chamber body.
For example, when the internal pressure of the chamber having an inner diameter of 300 mm is 7 MPa, a force of about 500,000 N (≈50,000 kgf) acts on the flange and the end plate, and the stud bolt and the shear key receive this load. The operation of the energy recovery chamber is such that the pressure inside the chamber is about 0.1 MPa when the seawater is sucked and 6 to 7 MPa when the concentrated seawater is pushed out, and pressure fluctuations from low pressure to high pressure are repeated. Therefore, the load in the axial direction of the stat bolt, the shear key, and the chamber body also repeats the load variation according to the pressure variation. This situation is the same when the openings at both ends of the metal chamber main body are closed with flanges, and the problem of suppressing deterioration of the material due to repeated loading exists regardless of the material of the chamber main body.
In particular, since the metal chamber is in a corrosive environment with seawater or concentrated seawater, the fatigue strength of the metal due to repeated pressure fluctuations and the strength deterioration due to corrosion are combined, so the durability study becomes more complicated.

Based on the above findings, the present inventors have conceived a means for receiving an axial load due to the chamber internal pressure applied to the end plates respectively closing the openings at both ends of the chamber body, and have led to the inventive idea. is there.
That is, according to the present invention, in an energy recovery chamber that uses the pressure energy of concentrated seawater as energy for boosting seawater, the load due to the chamber internal pressure applied to the end plates that respectively close the openings at both ends of the cylindrical chamber body is An object of the present invention is to provide an energy recovery chamber that does not act on the main body and can drastically reduce the load even if it acts.

In order to achieve the above-described object, the energy recovery chamber of the present invention uses the pressure energy of concentrated seawater discharged from a reverse osmosis membrane separation device that passes pressurized seawater and separates it into fresh water and concentrated seawater. An energy recovery chamber used for boosting the pressure of the chamber, the cylindrical chamber body and the openings at both ends of the chamber body are respectively closed, and a space for containing concentrated seawater and seawater is formed inside the chamber body together with the chamber body. An end plate, a concentrated seawater port for supplying and discharging concentrated seawater to the space, a seawater port for supplying and discharging seawater to the space, and connecting the endplates extending into the space, and the concentrated seawater in the space And / or a connecting rod that receives a load applied to the end plate by the pressure of seawater, and the at least one end plate is formed by the load by the chamber. Characterized in that to the body is movable in the axial direction of the connecting rod.
According to the present invention, the connecting rods that connect the end plates that respectively close the openings at both ends of the cylindrical chamber main body and receive the load applied to the end plates by the pressure of the concentrated seawater and / or seawater in the chamber are provided. Since it is provided, the load due to the chamber internal pressure applied to the end plate does not act on the chamber body, and even if it acts, the load can be drastically reduced.

According to a preferred aspect of the present invention, the chamber body is made of fiber reinforced plastic (FRP).
According to the present invention, since it is possible to receive an axial load applied to the end plate by the connecting rod, even if the chamber body is a chamber body made of fiber reinforced resin, the chamber body may be damaged or broken. This eliminates the need for a specially designed chamber that takes into account repeated axial loads.

According to a preferred aspect of the present invention, a seal plate for preventing fluid leakage is provided on the space side of the end plate.
According to the present invention, the liquid in the chamber (space) can be prevented from leaking outside by the seal plate. In addition, air can be prevented from being mixed from the outside of the chamber. Therefore, the end plate that closes the openings at both ends of the chamber body does not need to have a fluid sealing function.

According to a preferred aspect of the present invention, a shear key is provided on the side of the end plate opposite to the space, and movement of the end plate is limited so that the end plate does not shift out of the chamber body. To do.
According to the present invention, the movement is limited by the shear key so that the end plate does not shift to the outside of the chamber body. In other words, when the chamber inner pressure is not applied to the end plate, a gap is formed between the end plate and the shear key. When the chamber internal pressure is applied to the end plate, the connecting rod is extended to some extent under the tensile load, so that the gap between the end plate and the shear key is reduced. That is, the end plate can be moved in the axial direction along the cylindrical surface of the chamber body according to the extension of the connecting rod. If the clearance is set so that the end plate and the shear key abut, the shear key receives a part of the load applied to the end plate by the chamber internal pressure, but the shear key is not subjected to all axial loads due to the internal pressure. .

According to a preferred aspect of the present invention, one end of the end plate constitutes a flange, and the flange is fixed to an end of the chamber body via a fastener.
According to the present invention, one end plate of the flange structure is fixed to the chamber body, but the other end plate does not come into contact with the shear key with the maximum extension amount that the connecting rod extends due to the axial load caused by the chamber internal pressure. By setting a gap in the chamber, the axial load due to the chamber internal pressure is not applied to the chamber body.

According to a preferred aspect of the present invention, a rubber or resin lining is applied to the outer peripheral surface of the connecting rod, or the outer peripheral surface of the connecting rod is covered with a rubber or resin cover.
According to the present invention, since the outer peripheral surface of the connecting rod is covered with the rubber lining, the resin lining, or the rubber or resin cover, it is not necessary to configure the connecting rod with an expensive stainless steel, and an inexpensive steel material. Etc. can be used.

A first aspect of the energy recovery device of the present invention is the energy recovery chamber according to any one of claims 1 to 6, wherein the energy recovery chamber in which the longitudinal direction of the chamber body is arranged vertically; A perforated plate that is horizontally disposed on the concentrated seawater port side in the space and rectifies the concentrated seawater that has flowed into the space in the horizontal direction, and is disposed horizontally on the seawater port side in the space. And a perforated plate for rectifying the seawater flowing into the space in the horizontal direction in the space.
According to the present invention, by arranging two perforated plates in the horizontal direction at an interval in the vertical direction on the concentrated seawater port side, the flow flowing in from the small-diameter port is made to uniformly flow into the large-diameter chamber. To. Concentrated seawater and seawater that uniformly flowed into the chamber with a perforated plate try to separate vertically due to the difference in specific gravity, and at the same time, a uniform flow is formed in the vertical direction with the cross-sectional area of the chamber. The seawater can be pressurized and discharged by the concentrated seawater while maintaining the boundary between the concentrated seawater and seawater as a whole, that is, while suppressing mixing of the concentrated seawater and seawater. The same rectifying effect is produced when seawater flows from the upper seawater port through the perforated plate into the chamber.

According to a second aspect of the energy recovery apparatus of the present invention, the energy recovery chamber according to any one of claims 1 to 6 and a piston movable along the connecting rod by being penetrated by the connecting rod. It is characterized by comprising.
According to the present invention, the sliding movement (contact area) is drastically reduced by eliminating or minimizing the contact between the piston and the inner peripheral surface of the chamber body by guiding the movement of the piston with the connecting rod. Can be made. Therefore, compared with the energy recovery chamber using the conventional piston, the generation amount of wear powder can be reduced and the wear loss can be reduced. Further, the inner peripheral surface of the chamber main body does not need to guide the piston, and the chamber main body does not need high-precision finishing.

  The seawater desalination system of the present invention includes a high-pressure pump that boosts seawater, a reverse osmosis membrane separation device that separates fresh water and concentrated seawater through the pressurized seawater, and the reverse osmosis membrane separation device The energy recovery device according to claim 7 or 8 that pressurizes seawater by pressure energy of the separated concentrated seawater, and a booster pump that boosts the seawater pressurized by the energy recovery device and supplies the seawater to the reverse osmosis membrane separation device It is provided with.

The present invention has the following effects.
(1) According to the energy recovery chamber of the present invention, the end plates that respectively close the openings at both ends of the cylindrical chamber body are connected to each other, and the end plates are connected to the end plate by the pressure of the concentrated seawater and / or seawater in the chamber. Since the connecting rod that receives the applied load is provided, the load due to the chamber internal pressure applied to the end plate does not act on the chamber body. Depending on the structure, a part of the load applied to the end plate may act on the chamber body, but even in this case, the load applied to the chamber body can be drastically reduced. Therefore, even if the chamber body is made of fiber reinforced resin, the chamber body is not damaged or broken by the axial load applied to the end plate due to the internal pressure of the chamber. There is no need to make the chamber.
(2) Even when the opening of the chamber body is closed with the end plate of the flange structure, the bonding force for connecting the end plate of the flange structure to the chamber body may be low, so the number of bolts (or stud bolts) And the size of the bolt (or stud bolt) can be reduced.
(3) When a chamber in which a metal flange is welded to a metal chamber body is used, since a load is not repeatedly applied to the welded portion, fatigue failure does not occur.
(4) When the end plate is attached to the chamber body using a shear key, the shear key can be prevented from being subjected to repeated loads, and even if the shear key is subjected to repeated loads, this repeated load is dramatically increased. Therefore, reliability is improved.
(5) According to the energy recovery device in which the perforated plate is arranged in the energy recovery chamber of the present invention, the concentrated seawater is supplied and discharged from the lower part of the chamber, and the seawater is supplied and discharged from the upper part. The pressure transmission from the high-pressure concentrated seawater to the seawater can be performed while suppressing the mixing at the boundary portion where the two fluids contact while separating the concentrated seawater and the seawater up and down.
(6) According to the energy recovery device in which the piston is arranged in the energy recovery chamber of the present invention, the contact between the piston and the inner peripheral surface of the chamber main body is eliminated or minimized by guiding the piston with the connecting rod. The sliding area (contact area) can be drastically reduced. Therefore, compared with the energy recovery chamber using the conventional piston, the generation amount of wear powder can be reduced and the wear loss can be reduced. In addition, the inner peripheral surface of the chamber body does not need to guide the piston, and high-precision finishing is not necessary.

FIG. 1 is a schematic diagram showing a configuration example of a seawater desalination system in which the energy recovery chamber of the present invention is used. FIG. 2 is a cross-sectional view showing an embodiment of the energy recovery chamber of the present invention. FIGS. 3A, 3B, and 3C are enlarged cross-sectional views enlarging a portion III in FIG. 2, and are views showing a detailed structure of the shear key. FIG. 4 is a cross-sectional view showing another embodiment of the energy recovery chamber of the present invention. FIG. 5 is a sectional view showing still another embodiment of the energy recovery chamber of the present invention. FIG. 6 is a cross-sectional view showing still another embodiment of the energy recovery chamber of the present invention. FIG. 7 is a sectional view showing still another embodiment of the energy recovery chamber of the present invention. FIG. 8 is a cross-sectional view showing an energy recovery apparatus in which a perforated plate is arranged in the energy recovery chamber shown in FIG. FIG. 9 is a plan view showing the perforated plate. FIG. 10 is a view showing a fixing method of the perforated plate, and is an enlarged view of a main part of FIG. FIG. 11 is a cross-sectional view showing details of the perforated plate and the supporting portion of the support column. 12 is a cross-sectional view showing an energy recovery device in which a piston is arranged in the energy recovery chamber shown in FIG. FIG. 13 is a schematic diagram illustrating a configuration example of a conventional seawater desalination system. FIG. 14 is a schematic view showing a case where an energy recovery chamber is manufactured using fiber reinforced plastic.

  Hereinafter, embodiments of an energy recovery chamber according to the present invention will be described with reference to FIGS. 1 to 12, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic diagram showing a configuration example of a seawater desalination system in which the energy recovery chamber of the present invention is used. As shown in FIG. 1, seawater taken by a water intake pump (not shown) is pretreated by a pretreatment device and adjusted to a predetermined water quality condition, and then a motor M is directly connected via a seawater supply line 1. Supplied to the high-pressure pump 2. Seawater pressurized by the high-pressure pump 2 is supplied via a discharge line 3 to a reverse osmosis membrane separator 4 equipped with a reverse osmosis membrane (RO membrane). The reverse osmosis membrane separation device 4 obtains fresh water from seawater by separating seawater into concentrated seawater having a high salinity concentration and fresh water having a low salinity concentration. At this time, concentrated seawater with a high salinity is discharged from the reverse osmosis membrane separation device 4, but this concentrated seawater still has a high pressure. A concentrated seawater line 5 for discharging concentrated seawater from the reverse osmosis membrane separation device 4 is connected to a concentrated seawater port P1 of the energy recovery chamber 20 via a control valve 6. A seawater supply line 1 for supplying pretreated low-pressure seawater is branched upstream of the high-pressure pump 2 and connected to a seawater port P2 of the energy recovery chamber 20 via a valve 7. The energy recovery chamber 20 performs energy transmission while separating the two fluids at the boundary between concentrated seawater and seawater.

  The seawater pressurized using the pressure of the concentrated seawater in the energy recovery chamber 20 is supplied to the booster pump 8 via the valve 7. Then, the booster pump 8 further increases the pressure of the seawater so that the pressure becomes the same level as the discharge line 3 of the high-pressure pump 2, and the pressurized seawater merges with the discharge line 3 of the high-pressure pump 2 via the valve 9 and reverses. The osmotic membrane separation device 4 is supplied. On the other hand, the concentrated seawater that has lost its energy by boosting the seawater is discharged from the energy recovery chamber 20 to the concentrated seawater discharge line 17 via the control valve 6.

  FIG. 2 is a cross-sectional view showing an embodiment of the energy recovery chamber 20 of the present invention. As shown in FIG. 2, the energy recovery chamber 20 includes a cylindrical chamber body 21 made of fiber reinforced plastic (FRP) and end plates 22 and 22 that respectively close openings at both ends of the chamber body 21. Yes. A chamber (space) CH is formed inside the chamber body 21 and the end plates 22 and 22. A concentrated seawater port P1 for supplying and discharging concentrated seawater to the chamber CH is formed on one end side of the chamber body 21, and a seawater port P2 for supplying and discharging seawater to the chamber CH is formed on the other end side of the chamber body 21. ing. The chamber body 21 is formed with a large-diameter portion 21a in which the outer diameters at both ends are larger than the central portion.

  The two end plates 22 and 22 are connected by a connecting rod 23 that extends in the chamber body 21. The connecting rod 23 is disposed at the axial center of the cylindrical chamber body 21. Screw portions 23 s and 23 s are formed at both ends of the connecting rod 23, and end plates 22 and 22 are screwed into the screw portions 23 s and 23 s, and lock nuts are provided on the outer end face sides of the end plates 22 and 22. 24, 24 are provided. Thereby, the said two end plates 22 and 22 and the connection rod 23 are connected integrally. Since the connecting rod 23 is in contact with concentrated seawater or seawater, it is made of a metal having excellent seawater resistance such as duplex stainless steel. In addition, you may make it provide the port P1, P2 in the location which is not a connection part with the connection rod 23 in the end plate 22. FIG.

  On the chamber side of the two end plates 22 and 22, seal plates 25 and 25 for preventing leakage of concentrated seawater and seawater in the chamber CH are provided. That is, each seal plate 25 has a ring shape, the outer diameter side of the seal plate 25 is in close contact with the inner diameter side of the chamber body 21, the inner diameter side of the seal plate 25 is in close contact with the outer diameter side of the connecting rod 23, and the chamber CH Concentrated seawater and seawater are prevented from leaking outside. Furthermore, by providing the seal plates 25, 25, it is possible to prevent air from entering from the outside of the chamber. In addition, shear keys 26 and 26 are provided outside the two end plates 22 and 22 to restrict the end plates 22 and 22 from moving outside the chamber body 21. As the shear key of this embodiment, for example, a C-type retaining ring can be used. The diameter of the connecting rod 23, the threaded portion 23s and the lock nut 24, which are the fixing portions between the connecting rod 23 and the end plate 22, are configured to have sufficient strength to receive a load corresponding to the pressure of the fluid introduced into the chamber. .

  By configuring the energy recovery chamber 20 as shown in FIG. 2, the connecting rod 23 can receive the axial load due to the chamber internal pressure applied to the end plates 22 and 22 that respectively close the openings at both ends of the chamber body 21. Therefore, it is possible to prevent an axial load from being applied to the shear key 26 and the chamber body 21. The connecting rod 23 may not be disposed on the axial center of the chamber body 21, and a plurality of connecting rods 23 may be disposed. Since the connecting rod 23 holds the load that pushes the end plate 22 outward under the pressure in the chamber, the shear key 26 only restricts the movement so that the end plate 22 does not move out of the chamber.

  FIGS. 3A, 3B, and 3C are enlarged cross-sectional views enlarging a portion III in FIG. 2, and are views showing a detailed structure of the shear key 26. FIG. As shown in FIG. 3A, a ring-shaped grooved metal fitting 27 is fitted on the inner diameter side of the large-diameter portion 21a of the chamber body 21, and a retaining ring is formed in the groove of the grooved metal fitting 27. A key ring 28 is disposed, and the grooved bracket 27 and the key ring 28 constitute a shear key 26. As shown in FIG. 3A, when the chamber inner pressure is not applied to the end plate 22, a gap is formed between the end plate 22 and the key ring 28 of the shear key 26. When the chamber internal pressure is applied to the end plate 22, as shown in FIG. 3B, the connecting rod 23 receives a tensile load and extends somewhat, so that the gap between the end plate 22 and the key ring 28 is reduced. To do. That is, the end plate 22 and the seal plate 25 can move in the axial direction along the cylindrical surface of the chamber body 21 according to the extension of the connecting rod 23. In the configuration shown in FIG. 2, the left and right end plates 22, 22 and the seal plates 25, 25 of the chamber can be moved in the axial direction along the cylindrical surface of the chamber body 21. When a predetermined pressure is applied to the end plate 22 by the chamber internal pressure, as shown in FIG. 3C, if the gap is set such that the end plate 22 and the key ring 28 of the shear key 26 are in contact with each other, the end plate is set by the chamber internal pressure. The shear key 26 receives a part of the load applied to the 22, but the shear key 26 does not receive all the axial load due to the internal pressure.

  FIG. 4 is a cross-sectional view showing another embodiment of the energy recovery chamber 20 of the present invention. As shown in FIG. 4, one of the end plates at both ends of the cylindrical chamber main body 21 is an end plate 22 </ b> F having a flange structure, and the other is an end plate 22 whose movement is restricted by a shear key 26. That is, a stud bolt 31 is embedded in the large-diameter portion 21 a of the chamber body 21, the stud bolt 31 is provided so as to protrude from the end plate 22 F of the flange structure, and a nut 32 is tightened on the stud bolt 31, whereby the chamber body 21 The end plate 22F is fixed to the end surface of the. Then, like the one shown in FIG. 2, the movement of the other end plate 22 is restricted by the shear key 26 so that the end plate 22 does not shift out of the chamber. The other configuration of the energy recovery chamber 20 shown in FIG. 4 is the same as that of the energy recovery chamber 20 shown in FIG.

  When configured as shown in FIG. 4, one end plate 22F of the flange structure is fixed to the chamber body 21, but the other end plate 22 has the maximum extension amount that the connecting rod 23 extends due to the axial load caused by the chamber internal pressure. Since the gap (see FIG. 3A) is set so as not to contact the shear key 26, the axial load due to the chamber internal pressure is not applied to the chamber body 21.

  FIG. 5 is a cross-sectional view showing another embodiment of the energy recovery chamber 20 of the present invention. As shown in FIG. 5, the port P1 is disposed on an end plate 22F having a flange structure. The flange-structured end plate 22F is made of a metal having corrosion resistance such as stainless steel, and the port is similarly made of a metal such as stainless steel, and the flange-structured end plate 22F and the port P1 are welded and integrated. Since the end plate of the flange structure is made of stainless steel, a seal plate is not required, and a flange seal 22s such as a normal gasket or an O-ring is attached to keep the chamber watertight.

  FIG. 6 is a cross-sectional view showing still another embodiment of the energy recovery chamber 20 of the present invention. As shown in FIG. 6, a rubber lining or a resin lining LI is applied to the outer peripheral surface of the connecting rod 23 that connects the two end plates 22 and 22. Note that the outer peripheral surface of the connecting rod 23 may be covered with a rubber or resin cover instead of the rubber lining or the resin lining. By configuring as shown in FIG. 6, it is not necessary to configure the connecting rod 23 with an expensive stainless steel material, and an inexpensive steel material or the like can be used. Since the lining and cover and the metal connecting rod 23 are slightly expanded and contracted with pressure fluctuation, for example, silicon rubber or ethylene propylene rubber (EPDM) is used as the lining or cover rubber, and the lining or cover resin is used. For example, an ABS resin or a vinyl chloride resin may be used, and the material, elasticity, and durability suitable for the application may be obtained.

FIG. 7 is a cross-sectional view showing another embodiment of the energy recovery chamber 20 of the present invention. As shown in FIG. 7, the energy recovery chamber 20 includes a cylindrical chamber body 21 made of fiber reinforced plastic (FRP) and end plates 22 and 22 that respectively close openings at both ends of the chamber body 21. Yes. A chamber CH is formed inside the chamber body 21 and the end plates 22 and 22. A concentrated seawater port P1 for supplying and discharging concentrated seawater to the chamber CH is formed on one end side of the chamber body 21, and a seawater port P2 for supplying and discharging seawater to the chamber CH is formed on the other end side of the chamber body 21. ing. The chamber body 21 is formed with a large-diameter portion 21a in which the outer diameters at both ends are larger than the central portion.
The two end plates 22 and 22 are connected by a connecting rod 23 that extends in the chamber body 21. The connecting rod 23 is disposed at the axial center of the cylindrical chamber body 21. Screw portions 23 s and 23 s are formed at both ends of the connecting rod 23, and end plates 22 and 22 are screwed into the screw portions 23 s and 23 s, and lock nuts are provided on the outer end face sides of the end plates 22 and 22. 24, 24 are provided. Thereby, the said two end plates 22 and 22 and the connection rod 23 are connected integrally. Since the connecting rod 23 is in contact with concentrated seawater or seawater, it is made of a metal having excellent seawater resistance such as duplex stainless steel. In addition, you may make it provide the port P1, P2 in the location which is not a connection part with the connection rod 23 in the end plate 22. FIG.
On the chamber side of the two end plates 22 and 22, seal plates 25 and 25 for preventing leakage of concentrated seawater and seawater in the chamber CH are provided. That is, each seal plate 25 has a ring shape, the outer diameter side of the seal plate 25 is in close contact with the inner diameter side of the chamber body 21, the inner diameter side of the seal plate 25 is in close contact with the outer diameter side of the connecting rod 23, and the chamber CH Concentrated seawater and seawater are prevented from leaking outside. Furthermore, by providing the seal plates 25, 25, it is possible to prevent air from entering from the outside of the chamber.

Step portions are formed in the inner diameter portion in the vicinity of both end portions of the chamber body 21 so that the inner diameter D on both end sides is larger than the inner diameter d on the center side. The outer diameter portions of the two end plates 22 and 22 have a shape having a step portion having a large diameter portion 22l on the outer side and a small diameter portion on the chamber side (inner side). A predetermined gap is provided between the step portion at the outer diameter portion of the end plates 22 and 22 and the step portion formed at the inner diameter portion of the chamber body 21, and at least one end plate 22 is connected to the connecting rod 23. It is possible to move in the axial direction. And either of the step part formed in the outer diameter part of the end plates 22 and 22 of both ends, and the step part formed in the internal diameter part of the chamber main body 21 engages in the engaging part E, The end plate 22 Is restricted from moving out of the inner diameter of the chamber.
Since the load that pushes the end plate 22 to the outside due to the internal pressure of the chamber is held by the connecting rod 23, the steps of the chamber body 21 and the end plate 22 move so that the end plate 22 does not shift out of the chamber. It is only limiting.

  In the energy recovery chamber according to the present invention shown in FIGS. 2 to 7, the axial load received by the end plate 22 by the internal pressure of the chamber is received by the connecting rod 23, and the axial load is not received by the FRP chamber body 21. As described above, all the axial loads may be received by the connecting rod 23, or the axial loads may be distributed and received by both the connecting rod 23 and the chamber body 21. It is also possible. Moreover, although the example which comprised the chamber main body 21 by FRP was demonstrated, the chamber main body 21 is good also as a metal thing. When the chamber main body 21 is made of metal, a metal flange may be welded to one end of the chamber main body 21, and the end plate of the flange structure may be fixed to the metal flange with a bolt and a nut. Thus, even in the case of the metal chamber main body 21, since the connecting rod 23 receives a part of the axial load received by the end plate 22, the repeated load applied to the welded portion can be reduced, and fatigue failure does not occur. In addition, the number of bolts attached to the chamber can be reduced, and the size of the bolts can also be reduced.

Next, an energy recovery apparatus to which the energy recovery chamber 20 of the present invention shown in FIGS. 2 to 7 is applied will be described.
FIG. 8 is a cross-sectional view showing an energy recovery device in which perforated plates 40 are arranged in the energy recovery chamber 20 shown in FIG. In this embodiment, as shown in FIG. 8, the energy exchange chamber 20 is installed vertically. In other words, the long cylindrical chamber body 21 has the longitudinal direction of the chamber arranged in the vertical direction, and the concentrated seawater port P1 is disposed below the chamber CH so as to supply and drain the concentrated seawater below the chamber CH. The seawater port P2 is provided on the upper side of the chamber CH so as to supply and discharge seawater on the upper side of the chamber CH. In the chamber body 21, two perforated plates 40, 40 that rectify the fluid are arranged in the vicinity of the concentrated seawater port P1 and the seawater port P2. The perforated plates 40, 40 are arranged at a predetermined distance from the ports P1, P2.

FIG. 9 is a plan view showing the porous plate 40. As shown in FIG. 9, the perforated plate 40 is formed of a so-called punching plate in which a large number of small-diameter holes h are formed at equal intervals on a circular flat plate, and a through-hole TH through which the connecting rod 23 passes is formed at the center. ing.
FIG. 10 is a view showing a fixing method of the perforated plate 40 and is an enlarged view of a main part of FIG. As shown in FIG. 10, the perforated plate 40 is configured to be fixed to the seal plate 25 with a plurality of support columns 41.
FIG. 11 is a cross-sectional view showing details of the attachment portion of the perforated plate 40 and the support column 41. As shown in FIG. 11, the support column 41 has a female screw on one side and a male screw on one side. A female screw is formed on the seal plate 25, and the pillars 41 are fixed at three locations in the circumferential direction of the seal plate 25 (see FIG. 10). As shown in FIG. The perforated plate 40 is sandwiched between the upper and lower columns 41, 41 by screwing the male screw into the female screw of the other column 41. As shown in FIG. 10, the second perforated plate 40 fixes the support 41 by screwing a normal set screw 43 into the female screw of the support 41 through the hole h of the perforated plate 41.
As described above, by arranging the two perforated plates 40, the flow of the concentrated seawater and the seawater flowing from the small diameter ports P1 and P2 is made to uniformly flow into the large diameter chamber CH.

Here, the uniform flow means that the flow velocity and direction in a horizontal section in the chamber CH are uniform. That is, if the flow in an arbitrary horizontal section in the vertical direction in the chamber CH in FIG. 8 is the flow velocity and the direction of the arrow shown in the drawing is the flow direction, all the arrows have the same length and the same direction. means. This flow can be adjusted according to the porosity of the porous plate 40 arranged in the chamber CH and the arrangement position of the two porous plates 40 from the ports P1 and P2, and the optimal dimensions and arrangement position are determined by analysis or the like. .
The concentrated seawater and seawater that uniformly flowed into the chamber CH by the perforated plate 40 try to separate vertically due to the difference in specific gravity, and at the same time, a uniform flow is formed in the vertical direction with the chamber cross-sectional area. The boundary portion I is maintained and the boundary portion I between the concentrated seawater and the seawater is maintained as a whole, that is, while suppressing the mixing of the concentrated seawater and the seawater, the seawater can be pressurized and discharged by the concentrated seawater. The same rectifying effect is also obtained when seawater flows into the chamber from the upper seawater port P2 through the perforated plate 40.

  12 is a cross-sectional view showing an energy recovery device in which a piston is arranged in the energy recovery chamber 20 shown in FIG. This energy recovery device is a type of energy recovery device that separates concentrated seawater and seawater with a piston and pushes and pulls seawater, as in the prior art shown in FIG. Although the longitudinal direction of the energy recovery chamber shown in FIG. 12 is arranged in the horizontal direction, it is not necessarily limited to the horizontal direction. As shown in FIG. 12, a piston 50 that moves along the connecting rod 23 is disposed in the chamber CH. The piston 50 is provided with a guide member 51 at a sliding portion with the connecting rod 23. The guide member 51 is made of a resin or the like that reduces friction during movement and is durable against sliding friction with the connecting rod 23, and is provided on the inner periphery of the piston.

  Since the chamber of the embodiment shown in FIG. 12 is of a type that feeds and discharges concentrated seawater and seawater from the side of the chamber, the connecting rod 23 has a stopper 52, so that the piston 50 does not pass through the ports P1 and P2. 52 is provided. Therefore, even if the piston 50 shown by the broken line in FIG. 12 moves to the concentrated seawater port side to the maximum, the piston 50 stops at the stopper 52 and the movement is restricted so as not to go to the left from the concentrated seawater port P1. . The stopper 52 is configured by attaching a ring-shaped member having a diameter larger than that of the connecting rod 23 to the connecting rod 23 after passing the piston 50 through the connecting rod 23. The stopper 52 is similarly provided on the seawater port side, and the piston 50 reciprocates between the stoppers 52 and 52 in the axial direction according to the supply and drainage of the concentrated seawater and seawater, and one fluid separated by the piston is supplied to the other. Operate to drain with fluid. Thereby, seawater can be pressurized and discharged by concentrated seawater.

  According to the energy recovery apparatus shown in FIG. 12, the piston 50 is guided by the connecting rod 23, thereby eliminating or minimizing contact between the piston 50 and the inner peripheral surface of the chamber body 21. Area) can be drastically reduced. Therefore, compared with the energy recovery chamber using the conventional piston, the generation amount of wear powder can be reduced and the wear loss can be reduced. Further, the inner peripheral surface of the chamber main body 21 does not need to guide the piston 50, and the chamber main body 21 does not require high-precision finishing.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and needless to say, may be implemented in various forms within the scope of the technical idea. The form and the like of the energy recovery chamber are not limited to the illustrated examples described above, and it goes without saying that various changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Seawater supply line 2 High pressure pump 3 Discharge line 4 Reverse osmosis membrane separator 5 Concentrated seawater line 6 Control valve 7 Valve 8 Booster pump 17 Concentrated seawater discharge line 20 Energy recovery chamber 21 Chamber main body 21a Large diameter part 22 End plate 22s Flange seal 22F Flange-shaped end plate 22l Large diameter part of end plate 23 Connecting rod 23s Screw part 24 Lock nut 25 Seal plate 26 Shear key 27 Grooved metal fitting 28 Key ring 31 Stud bolt 32 Nut 40 Perforated plate 41 Post 43 Set screw 50 Piston 51 Guide Member 52 Stopper CH Chamber (space)
P1, P2 Seawater port TH Through hole

Claims (9)

An energy recovery chamber that utilizes the pressure energy of concentrated seawater discharged from a reverse osmosis membrane separation device that passes pressurized seawater and separates it into fresh water and concentrated seawater,
A cylindrical chamber body;
End plates that respectively close the openings at both ends of the chamber body and form a space for containing concentrated seawater and seawater together with the chamber body;
A concentrated seawater port for supplying and discharging concentrated seawater to the space;
A seawater port for supplying and discharging seawater to the space;
A connecting rod that extends into the space and connects the end plates, and receives a load applied to the end plates by the pressure of the concentrated seawater and / or seawater in the space;
The energy recovery chamber, wherein the at least one end plate is movable in the axial direction of the connecting rod with respect to the chamber body by the load.   The energy recovery chamber according to claim 1, wherein the chamber body is made of fiber reinforced plastic (FRP).   The energy recovery chamber according to claim 1, wherein a seal plate for preventing fluid leakage is provided on the space side of the end plate.   The energy recovery chamber according to claim 1, wherein a shear key is provided on a side of the end plate opposite to the space, and movement of the end plate is restricted so that the end plate does not shift out of the chamber body. .   The energy recovery chamber according to claim 1, wherein one of the end plates constitutes a flange, and the flange is fixed to an end of the chamber body via a fastener.   The energy recovery chamber according to claim 1, wherein the outer peripheral surface of the connecting rod is provided with a rubber or resin lining, or the outer peripheral surface of the connecting rod is covered with a rubber or resin cover. The energy recovery chamber according to any one of claims 1 to 6, wherein an energy recovery chamber in which a longitudinal direction of the chamber body is arranged vertically;
A perforated plate arranged horizontally on the concentrated seawater port side in the space and rectifying the concentrated seawater flowing into the space in the horizontal direction;
An energy recovery apparatus comprising: a perforated plate arranged horizontally on the seawater port side in the space and rectifying the seawater flowing into the space in the horizontal direction in the space. The energy recovery chamber according to any one of claims 1 to 6,
An energy recovery apparatus comprising: a piston that is penetrated by the connecting rod and is movable along the connecting rod. A high-pressure pump for boosting seawater;
A reverse osmosis membrane separation device that separates fresh water and concentrated seawater by passing pressurized seawater;
The energy recovery device according to claim 7 or 8, wherein the seawater is pressurized by pressure energy of the concentrated seawater separated from fresh water by the reverse osmosis membrane separation device;
A seawater desalination system comprising a booster pump that pressurizes seawater pressurized by the energy recovery device and supplies the seawater to the reverse osmosis membrane separation device.

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