JP6216847B2 - Reverse osmosis processing equipment - Google Patents

Description

  The present invention relates to a reverse osmosis treatment apparatus, and more particularly to a reverse osmosis treatment apparatus capable of easily exchanging elements.

  In a desalination treatment apparatus using a reverse osmosis membrane (hereinafter referred to as RO (Reverse Osmosis) membrane), a reverse osmosis pressure is utilized. Therefore, as shown in FIG. The RO membrane elements 222 are arranged in series, and each RO membrane element 222 is connected by a water collecting pipe 234 at the center of the RO membrane element 222. Supply water is supplied from one of the desalination treatment devices by a high-pressure pump, and the inside of the pressurized container 224 is pressurized by the opening degree of a valve installed on the concentrated water side. When the pressurized pressure exceeds the osmotic pressure of the supplied water, it passes through the RO membrane, and desalinated water (permeated water) flows into the central water collecting pipe 234.

  The supply water supplied into the pressurized container 224 has a salt concentration that increases from the supply water side to the concentrated water side, so that the pressure in the pressurized container 224 finally becomes the final stage salt concentration and the amount of permeated water. The pressure to be pressurized is determined by the supply water flow velocity on the membrane surface. Accordingly, since the pressure on the supply water side in the pressurized container 224 is more than necessary, the amount of permeated water increases. For example, FIG. 9 shows the relationship between the position of the RO membrane element and the relative flux (relative flux) when seven RO membrane elements 222 are arranged in series. The element position in FIG. 9 is the number from the supply water side. As shown in FIG. 9, it can be seen that the amount of permeated water on the supply water side is large, and the amount of permeated water decreases as it goes to the concentrated water side. This is because the salt concentration of the treated water increases as it goes to the concentrated water side, so a high pressure is required on the concentrated water side, but the same pressure is also applied on the supply water side. This is because more permeated water is generated. As described above, as shown in FIG. 9, the amount of permeated water in the pressurized container 224 is non-uniform, so that necessary power increases and contamination of the RO membrane element on the supply water side proceeds.

  In order to solve such a problem, for example, in Patent Document 1 below, a plug that closes the water collection pipe at the connection portion of the RO membrane element at the center of the pressurized container, and the front and rear from the water collection pipe A seawater desalination apparatus provided with a permeate line that discharges the separated permeate to the outside is described.

JP 2010-179264 A

  When exchanging the RO membrane element, the RO membrane element on the supply water side, which is most likely to become dirty, is usually removed, and the RO membrane element is newly added to the concentrated water side. However, in the apparatus described in Patent Document 1, since the plug that closes the water collecting pipe is provided at the connection portion of the RO membrane element, the position of the plug changes when the replacement is performed in this way. Therefore, it was not possible to do it. Therefore, it is necessary to disassemble the RO membrane element once and reattach the plug, which is troublesome.

  This invention is made | formed in view of such a situation, and it aims at providing the reverse osmosis processing apparatus which can replace | exchange RO membrane element easily.

According to a first aspect of the present invention, in order to achieve the above object, a first pressure vessel for primary treatment of water to be treated and a second pressure vessel for secondary treatment of the water to be treated treated by the primary treatment In the first pressure vessel and the second pressure vessel, a plurality of reverse osmosis membrane elements each having a reverse osmosis membrane are connected in series by a water collection pipe through which permeate flows. The first pressure vessel has an inlet pipe for supplying the treated water at one end, and a first concentrated water discharge pipe for discharging the treated water subjected to the primary treatment at the other end. And a first discharge pipe for discharging permeated water, wherein the second pressure vessel has an introduction pipe for introducing the treated water subjected to the primary treatment at one end, and the other end. A second concentrated water discharge pipe for discharging the treated water subjected to the secondary treatment and a permeate discharge The number of the reverse osmosis membrane elements in the first pressure vessel is smaller than the number of the reverse osmosis membrane elements in the second pressure vessel, A first valve for adjusting the flow rate of the permeated water in the discharge pipe, a second valve for adjusting the flow rate of the treated water secondary-treated in the second concentrated water discharge pipe, and the first A measuring instrument for measuring the flow rate or electrical conductivity of the permeated water discharged from the second discharging pipe and the second discharging pipe, and based on the measured value of the measuring instrument, the first valve or the second by adjusting the valve, provides a reverse osmosis treatment apparatus characterized by adjusting the flow rate of the permeated water to be processed in the first pressure vessel and the second pressure vessel.

  When reverse osmosis treatment is performed by connecting multiple reverse osmosis membrane elements in series, the reverse osmosis membrane on the supply water side of the treated water is likely to become dirty, so the reverse osmosis membrane element on the supply water side is frequently replaced. Become. According to the first aspect, the work can be performed by exchanging the reverse osmosis membrane element of the first pressure vessel, which is easily contaminated, by dividing the first pressure vessel and the second pressure vessel. Furthermore, since the number of reverse osmosis membrane elements in the first pressure vessel is smaller than the number of reverse osmosis membrane elements in the second pressure vessel, replacement can be easily performed. In addition, the reverse osmosis membrane element in the second pressure vessel which is hardly soiled does not need to be replaced, and can be used for a long period of time.

  Further, a large amount of permeated water is permeated from the supply water side of the reverse osmosis membrane element. Therefore, the water to be treated supplied into the second pressure vessel is less than the water to be treated introduced into the first pressure vessel. Therefore, by providing a plurality of first pressure vessels with respect to the second pressure vessel, the water to be treated discharged from the plurality of first pressure vessels can be treated with the second pressure vessel, Processing can be performed efficiently.

  In addition, the flow rate of the permeated water can be adjusted using the first valve. By reducing the amount of permeated water in the first pressure vessel, the salt concentration of the first treated water can be lowered. Therefore, in the secondary treatment, the amount of permeated water can be increased even if the applied pressure is low, so that the amount of permeated water can be increased as a whole apparatus.

  Moreover, the flow volume of the permeated water processed with a 2nd pressure vessel can be adjusted by adjusting a 2nd valve | bulb.

  According to the present invention, since the pressure vessel is divided into two parts, a first pressure vessel for primary treatment and a second pressure vessel for secondary treatment, only the first pressure vessel is disassembled, The exchange can be easily performed by exchanging the reverse osmosis membrane element which is easily contaminated. Further, since the reverse osmosis membrane element in the second pressurized container is hardly contaminated, the number of exchanges can be reduced and it can be used for a long time.

It is a block diagram of the desalination processing system in which the reverse osmosis processing apparatus of embodiment was installed. It is the perspective view which showed the structure of the element of the reverse osmosis processing apparatus of embodiment. It is the front view of the element which showed the state before RO membrane of the element shown in FIG. 2 was wound. FIG. 3 is a front view of the element shown in FIG. 2. It is sectional drawing which shows schematic structure of the reverse osmosis processing apparatus of embodiment. It is the graph which showed the relationship between the position of RO membrane element of the reverse osmosis processing apparatus of embodiment, and the relative flux of permeated water. It is sectional drawing which shows schematic structure of the reverse osmosis processing apparatus of other embodiment. It is sectional drawing which shows schematic structure of the conventional reverse osmosis processing apparatus. It is the graph which showed the relationship between the position of RO membrane element of the conventional reverse osmosis processing apparatus, and the relative flux of permeate.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described with reference to the following preferred embodiments, but can be modified in many ways without departing from the scope of the present invention, and other embodiments than the present embodiment can be utilized. be able to. Accordingly, all modifications within the scope of the present invention are included in the claims.

  FIG. 1 is a block diagram of a desalination treatment system 20 in which a reverse osmosis treatment apparatus 10 according to an embodiment is incorporated. In addition, the desalination processing system in this invention can be used for the system which carries out reverse osmosis processing of to-be-processed water, such as drainage reuse, pure water manufacture, brine water desalination, seawater desalination, etc., for example.

  A desalination treatment system 20 shown in the figure includes a tank 12 in which treated water is stored, a high-pressure pump 14, and a reverse osmosis treatment device 10. The water to be treated in the tank 12 is supplied to the reverse osmosis treatment device 10 by the high pressure pump 14 at a high pressure, and is subjected to reverse osmosis treatment (desalting treatment) by each RO membrane (treatment membrane) of the reverse osmosis treatment device 10. The water is separated into desalted permeated water (separated water) 16 and concentrated water (treated water) 18 in which the salt content is concentrated. The permeated water 16 thus obtained is discharged to the outside of the reverse osmosis treatment device 10 through a discharge pipe, and the concentrated water 18 is similarly discharged through a discharge pipe different from the discharge pipe for discharging the permeated water. It is discharged outside the reverse osmosis treatment apparatus 10. In addition, although the desalination processing system 20 of embodiment supplies the to-be-processed water to the reverse osmosis processing apparatus 10 with the high voltage | pressure pump 14 at high pressure, a valve is provided in the concentrated water outlet side of the reverse osmosis processing apparatus 10, The pressure in the reverse osmosis treatment apparatus 10 is set according to the opening of the valve.

  As the water to be treated in the tank 12, raw water may be used as it is, but it is preferable to use water to be treated that has been pretreated to remove turbid components contained in the raw water. Pretreatment includes use of a filter and treatment such as introducing raw water into a sedimentation basin and adding a sterilizing agent such as chlorine to precipitate and remove particles in the raw water and sterilize microorganisms. In addition, water to be treated may be used by adding a flocculant such as iron chloride to raw water to agglomerate turbid components and filtering them off.

  The reverse osmosis treatment apparatus 10 connects one or a plurality of elements 22 shown in FIG. 2 in series, and fills the cylindrical first vessel 80 and second vessel 82 shown in FIG. The first module 84 and the second module 86 are configured by connecting the first module 84 and the second module 86 as a single unit or in parallel.

  As shown in FIG. 2, the element 22 is configured by arranging a membrane unit 32 including an RO membrane 28 and a discharge pipe 30 around a water collection pipe 34. As shown in FIG. 3, the membrane unit 32 has four bag-like RO membranes 28, 28... Radially connected to the outer periphery of the water collecting pipe 34. These RO membranes 28, 28. It is configured by winding in a spiral around the water collection pipe 34. One end of the bag-like RO membrane 28 is opened, and the RO membrane 28 is bonded to the water collection pipe 34 so that the opening communicates with the through hole 36 of the water collection pipe 34 shown in FIG. The water to be treated flows on the outer surface of the RO membrane 28 and passes through the RO membrane 28 to be desalted. Then, the desalted water that has passed through the RO membrane 28 is collected from the inside of the RO membrane 28 into the water collection pipe 34 through the opening of the RO membrane 28 and the through holes 36 of the water collection pipe 34. The water is discharged from the element 22 from the water collecting pipe 34 through the discharge pipe 30. 3 is a mesh spacer disposed inside the RO membrane 28. The spacer 38 holds the RO membrane 28 so that the inner space of the RO membrane 28 is not crushed even when the RO membrane 28 is wound in a spiral shape. Reference numeral 40 denotes a mesh spacer disposed between the adjacent RO membranes 28 and 28. The spacers 40 are also radially bonded to the outer periphery of the water collecting pipe 34 in the same manner as the RO membrane 28.

  FIG. 5 is a cross-sectional view of the reverse osmosis treatment apparatus 10 according to the embodiment. In the present embodiment, a first module 84 that performs a primary process in which two elements 22 are connected in series is shown in the first vessel 80, and the second vessel 82 has five A second module 86 for performing secondary processing with the elements 22 connected in series is shown. The end of the first vessel 80 is opened so that the water to be treated is introduced and the first concentrated water (primary treated water) remaining without being treated in the first vessel 80 is discharged. Concentrated water (primary treated water) discharged from the first vessel 80 is also introduced into the end portion of the second vessel 82, and the second remaining without being treated in the second vessel 82. The concentrated water (second treated water to be treated) is opened. A predetermined operating pressure is applied to the opening on the introduction side of the first vessel 80 by the high-pressure pump 14. In addition, the first vessel 80 and the second vessel 82 can be configured by FRP or the like so as to withstand high pressure (5 MPa or more). The first vessel 80 and the second vessel 82 are also preferably connected by a tube made of a material that can withstand high pressure.

  As shown in FIG. 5, in the first vessel 80, the introduction pipe 56 that introduces the water to be treated into the first vessel 80, and the first water in which the water to be treated does not permeate the water collecting pipe 34. A first concentrated water discharge pipe 62 for discharging concentrated water is provided. The permeated water collected in the water collection pipe 34 through the RO membrane 28 is discharged from the first vessel 80 via the first discharge pipe 58 provided on the first concentrated water discharge pipe 62 side. The A meter 66 and a first valve 64 are provided at the outlet of the first discharge pipe 58.

  In the second vessel 82, the introduction pipe 68 for introducing the first concentrated water discharged from the first vessel 80 and the second second vessel 82 that does not pass through the water collection pipe 34 remain in the second vessel 82. The second concentrated water discharge pipe 70 for discharging the concentrated water is provided. A concentrated water discharge valve 74 that adjusts the pressure in the second vessel 82 is provided at the outlet of the second concentrated water discharge pipe 70. The permeated water collected in the water collection pipe 34 through the RO membrane 28 is discharged from the second vessel 82 via the second discharge pipe 72 provided on the second concentrated water discharge pipe 70 side. The A meter 76 is provided at the outlet of the second discharge pipe 72.

  According to the reverse osmosis treatment apparatus 10, the water to be treated supplied from the tank 12 of FIG. 1 via the introduction pipe 56 is guided to the element 22 through the flow path 57, and the water to be treated is the RO of the element 22. After sequentially passing through the membrane 28, water is collected in the water collection pipe 34. In the present embodiment, the reverse osmosis treatment is performed in two stages with the first vessel 80 and the second vessel 82, and the permeated water treated in the first vessel 80 is the first discharge pipe. It is discharged from the first vessel 80 via 58. The first concentrated water remaining without passing through the water collection pipe 34 is discharged from the first concentrated water discharge pipe 62, supplied via the introduction pipe 68 of the second vessel 82, and via the flow path 69. After being guided to the element 22 and sequentially passing through the RO membrane 28, the water is collected in the water collection pipe 34. The permeate treated in the second vessel 82 is discharged from the second vessel 82 via the second discharge pipe 72. The second concentrated water remaining without passing through the water collecting pipe 34 is discharged from the second concentrated water discharge pipe 70.

  FIG. 6 is a diagram illustrating the relationship between the position of the RO membrane element and the relative flux of the permeated water in the reverse osmosis treatment device of the embodiment. The data of the present invention is data obtained by performing an experiment with two elements installed in the first vessel and five elements installed in the second vessel. Conventionally, a large amount of permeate was generated from the supply water side, and the amount of permeate decreased as it went to the concentrated water side. This is because the pressure applied in the vessel is determined by the pressure applied to the last stage element. On the other hand, in the present invention, the pressure inside the first vessel 80 can be adjusted by the first valve 64, so that the relative flux can be set to a desired value as shown in FIG. The amount of permeated water can be reduced. By reducing the amount of permeated water in the first vessel 80, the salt concentration of the first concentrated water can be lowered. Therefore, as shown in element positions 3 to 7 in FIG. The amount of permeated water can also be increased. Therefore, the non-uniformity of the permeated water amount of each RO membrane element can be eliminated, whereby the permeated water amount can be increased as a whole apparatus.

  The flow rate in the first vessel 80 can be adjusted by adjusting the opening of the first valve 64 based on the numerical value measured by the measuring instrument 66, and the flow rate in the second vessel 82 is also measured. This can be done by adjusting the opening of the concentrated water discharge valve 74 according to the numerical value measured by the vessel 76. It is also possible to control the flow rate of the permeated water by providing a pressure gauge between the high-pressure pump 14 and the reverse osmosis treatment apparatus 10 and adjusting the high-pressure pump 14 according to the numerical value of the pressure gauge. As the measuring instruments 66 and 76, a flow meter, a pressure gauge, and an electric conductivity meter can be used. By measuring the electrical conductivity, the salt concentration rejection rate changes, so the amount of permeated water can be confirmed by monitoring the salt concentration rejection rate.

  In FIG. 5, the number of elements 22 is two in the first vessel 80 and five in the second vessel 82, but is not limited to this. is not. However, the number of elements 22 in the first vessel 80 is preferably equal to or less than the number of elements in the second vessel 82. Since the element 22 on the supply water side is easily contaminated, the permeated water can be efficiently generated as a whole apparatus by replacing the element 22 in the first vessel 80. Therefore, by reducing the number of elements 22 in the first vessel 80, the elements 22 in the first vessel 80 can be easily replaced. From FIG. 6, it is preferable to use two elements in the first vessel 80 in consideration of discharging the permeated water from the first vessel 80, but from the point of dirt, one element is used. Arrangement is also sufficient. The number of elements in the first vessel 80 is preferably 1 to 4, more preferably 2 to 3.

FIG. 7 is a cross-sectional view of the reverse osmosis treatment apparatus 110 according to another embodiment. The reverse osmosis treatment apparatus 110 shown in FIG. 7 is different from the reverse osmosis treatment apparatus 10 shown in FIG. 5 in that two first vessels 80 a and 80 b are installed. The amount of permeate increases the amount to be processed in the first vessel 80 a, in 80 b, a first amount of concentrate remains without being processed in the first vessel 80 a, 80 b is reduced. The first plurality as shown in FIG. 7 the first concentrated water from the vessel can be performed efficiently treated by supplying to the second vessel 82 b. Also in the reverse osmosis processing apparatus 110 shown in FIG. 7, measuring instruments 66a and 66b and first valves 64a and 64b are provided in the first vessels 80a and 80b, respectively, and each of the first valves 64a and 64b The amount of permeated water can be adjusted by adjusting the pressure in the first vessels 80a and 80b.

According to the present invention, the non-uniformity of the permeated water amount of each element 22, 22 ... can be eliminated, and a large amount of permeated water can be obtained at a low pressure. In addition, by dividing the pressure vessel into two parts and reducing the number of RO membrane elements in the upstream pressure vessel where the RO membrane is easily contaminated, the replacement can be facilitated and the downstream pressure vessel where the RO membrane is difficult to become dirty can be used for a long time. Can be used over a wide range.

  DESCRIPTION OF SYMBOLS 10,110 ... Reverse osmosis processing apparatus, 12 ... Tank, 14 ... High pressure pump, 16 ... Permeated water, 18 ... Concentrated water, 20 ... Desalination processing system, 22 ... Element, 24 ... Vessel, 28 ... RO membrane, 30 ... Exhaust pipe, 32 ... membrane unit, 34 ... water collecting pipe, 36 ... through hole, 38, 40 ... spacer, 56 ... introduction pipe, 57 ... flow path, 58 ... first exhaust pipe, 62 ... first concentrated water Discharge pipe, 64 ... first valve, 66, 76 ... measuring instrument, 68 ... introduction pipe, 69 ... flow path, 70 ... second concentrated water discharge pipe, 72 ... second discharge pipe, 74 ... second Valve, 80 ... first vessel, 82 ... second vessel, 84 ... first module, 86 ... second module

Claims (1)

A first pressure vessel for primary treatment of water to be treated; and a second pressure vessel for secondary treatment of the water to be treated treated by the primary treatment,
In the first pressure vessel and the second pressure vessel,
A plurality of reverse osmosis membrane elements provided with reverse osmosis membranes are arranged in series by a water collection pipe through which permeate flows,
The first pressure vessel has an inlet pipe for supplying treated water at one end, and a first concentrated water discharge pipe for discharging the treated water subjected to the primary treatment at the other end. A first discharge pipe for discharging permeated water,
The second pressure vessel has an introduction pipe for introducing the first-treated water to be treated at one end, and a second pipe for discharging the second-treated water to be treated at the other end. 2 concentrated water discharge pipes, and a second discharge pipe for discharging permeated water,
The number of reverse osmosis membrane elements in the first pressure vessel is less than the number of reverse osmosis membrane elements in the second pressure vessel;
A first valve for adjusting a flow rate of permeated water in the first discharge pipe, a second valve for adjusting a flow rate of the treated water secondary-treated in the second concentrated water discharge pipe,
A measuring instrument for measuring a flow rate or electric conductivity of permeated water discharged from the first discharge pipe and the second discharge pipe, and based on the measurement value of the measuring instrument, by adjusting the second valve, reverse osmosis treatment apparatus characterized by adjusting the flow rate of the permeated water to be processed in the first pressure vessel and the second pressure vessel.

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