JP4915844B2 - Softening device and method of operating softening device - Google Patents

Description

  The present invention relates to a softening device that can reduce the amount of regenerant used and a method of operating a water softening device.

  Water containing a large amount of divalent cations (hardness components) such as calcium ions and magnesium ions is called hard water and is unsuitable for use in boiler feed water or cooling water. For this reason, a hard water softening process is performed in order to remove divalent cations. As a method for removing the divalent cations and performing the water softening treatment, a salt softening method in which soft water is passed through the packed bed of Na-type strongly acidic cation exchange resin, or a reverse osmosis membrane method in which soft water is passed through the hard water into the reverse osmosis membrane and so on.

The salt softening method using Na-type strongly acidic cation exchange resin is a regeneration method in which saline solution is passed because the hardness component leaks into the treated water when the amount of ion exchanged hardness component exceeds the exchange capacity of the cation exchange resin. A process is required. In this regeneration step, since a salt solution of about 5 to 10% is usually supplied at SV5 to 15 for 20 minutes or more, a large amount of salt is required, and there is a disadvantage that the replenishment frequency of the saline solution is high. Conventionally, few softening devices are known for performing the water sampling process using the salt softening method and the electrical regeneration process, and the water flow volume can be changed only by changing the flow direction of the water to be treated including the hardness component. However, there is no device that can reduce the amount of regenerant used, and no softening device has been known. Accordingly, it has been desired to develop a softening device that can save regenerative medicine and can take various operation modes.
“Latest ion exchange”; Hidetake Kakihana et al., Published by Yodogawa Shoten, issued July 5, 1960, pages 385-386

  Therefore, the object of the present invention is to change the flow direction of the water to be treated containing the hardness component, to increase the flow volume, to decrease the flow rate and to increase the flow time, An object of the present invention is to provide a softening device and a method of operating the softening device that can significantly reduce the amount of regenerant used in the electrical regeneration process.

  In such a situation, the present inventor has intensively studied, and as a result, water passage through which a monovalent cation selective permeation membrane and a cation exchange membrane are alternately arranged between the anode chamber and the cathode chamber and the cation exchanger is filled therebetween. The first water flow chamber located on the cathode side of the monovalent cation selective permeation membrane and the anode side of the monovalent cation selective permeation membrane for the water to be treated containing hardness components in a state where no direct current is applied. A water collection step for obtaining soft water by passing water through two water passages, and in a state where a direct current is applied, regenerated water containing monovalent cations is serially connected to the first water passage and the second water passage in this order. According to the operation method of the softening device that alternately repeats the regeneration process of regenerating the cation exchanger by passing water, simply changing the flow direction of the water to be treated including the hardness component can increase the flow volume. , The water flow capacity can be reduced and the water flow time can be taken longer, And, in electrical regeneration step, it found like can be significantly reduced amount of regenerant, and have completed the present invention.

  That is, the present invention provides a monovalent cation selective permeable membrane in which a monovalent cation selective permeable membrane and a cation exchange membrane are alternately arranged between an anode chamber and a cathode chamber, and a water passage chamber filled with a cation exchanger is provided therebetween. The first water passage located on the cathode side of the first water passage and the second water passage located on the anode side of the monovalent cation selective permeable membrane are provided with a water introduction path and a discharge path, respectively. Each chamber is provided with a water introduction path and a discharge path, respectively, and water to be treated containing hardness components is passed through both the first water passage chamber and the second water passage chamber in parallel to obtain soft water. A soft water sampling route is provided, and a regeneration route for regenerating the cation exchanger by regenerating water containing monovalent cations from the first water passage to the second water passage in series is provided. A softening device is provided.

  The present invention also provides a monovalent cation selective permeable membrane in which a monovalent cation selective permeable membrane and a cation exchange membrane are alternately arranged between an anode chamber and a cathode chamber, and a water passage chamber filled with a cation exchanger is provided therebetween. The first water passage located on the cathode side of the first water passage and the second water passage located on the anode side of the monovalent cation selective permeable membrane are provided with a water introduction path and a discharge path, respectively. Each of the chambers is provided with a water introduction path and a discharge path, and the water to be treated containing the hardness component is passed in series from the second water flow chamber to the first water flow chamber to obtain soft water. A softening path characterized by providing a regeneration path for regenerating the cation exchanger by passing a regenerated water containing a monovalent cation in series from the first water passage to the second water passage. A device is provided.

  In the present invention, a monovalent cation selective permeation membrane and a cation exchange membrane are alternately arranged between the anode chamber and the cathode chamber, and a water passage chamber filled with a cation exchanger is provided between them, and a direct current is not applied. Then, the water to be treated containing the hardness component is passed through the first water passage located on the cathode side of the monovalent cation selective permeable membrane and the second water passage located on the anode side of the monovalent cation selective permeable membrane. A water collection step for obtaining soft water, and regeneration water containing monovalent cations are passed in series from the first water flow chamber to the second water flow chamber in a state where a direct current is applied to regenerate the cation exchanger. The present invention provides a method of operating a softening device characterized by alternately repeating the regeneration process.

  In the water sampling process in the softening device of the present invention, the water flow volume can be increased or the water flow rate can be decreased and the water flow time can be increased by simply changing the flow direction of the water to be treated including the hardness component. be able to. Further, in the regeneration step, the monovalent cation is returned from the second water flow chamber located downstream to the first water flow chamber located upstream, so that the monovalent cation concentration in the system can be kept high. Significant savings. In addition, if a plurality of softening devices are connected in parallel and operated such that the water sampling step and the regeneration step are alternately performed between the devices, soft water can be collected substantially continuously. Also, the anode outlet water obtained in the regeneration process has a reduced cation and pH, and hypochlorous acid is generated by the anodic reaction and has oxidizing power and bactericidal power. Can do. Further, the cathode outlet water obtained in the regeneration step can be used as alkaline functional water having a reducing power because cations increase to increase the pH and hydrogen gas is generated by the cathode reaction.

  A softening device according to a first embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG. 1 and 2 are schematic diagrams of the softening device of this example, in which FIG. 1 is a flow diagram for carrying out a water sampling process, FIG. 2 is a flow chart for carrying out a regeneration process, and FIG. 7 is a cation in the regeneration process. It is a figure explaining movement of. In the softening device 10, the monovalent cation selective permeable membrane 4 and the cation exchange membrane 3 are alternately arranged between the anode chamber 6 adjacent to the anode 16 and the cathode chamber 5 adjacent to the cathode 15, and the cation exchange resin 19 is interposed between them. The first water passage 1 is located on the cathode 15 side of the monovalent cation selective permeable membrane 4 and the second water chamber 2 is located on the anode 16 side of the monovalent cation selective permeable membrane 4. Are provided with water introduction pipes and discharge pipes, respectively, and the anode chamber 6 and the cathode chamber 5 are respectively provided with water introduction pipes 17 and 13 and discharge pipes 12 and 14, respectively. A soft water sampling piping system X that obtains soft water by passing water in parallel to both the first water flow chamber 1 and the second water flow chamber 2 is disposed, and a regenerant containing a monovalent cation is supplied to the first water flow chamber 1. And regenerating the cation exchange resin 19 by passing water through the second water passage 2 in series in this order. Arrange piping system Y, which arrangement the valve such that partitions the reproduction piping system Y soft water water sampling pipe system X. The ion exchange membrane adjacent to the anode chamber 6 may be a monovalent cation selective permeable membrane 4 as in this example. During regeneration, the hardness component enters the electrosoftening device from the water flowing through the anode chamber 6. This is preferable in that it can be prevented. In the present invention, the cation exchanger is not particularly limited, and examples thereof include cation exchange resins, cation exchange fibers, and organic porous cation exchangers.

  In the soft water sampling pipe system X, the first water passage 1 is connected to branch pipes 71, 72, 73 branched from the treated water introduction pipe 7 and a second connection pipe 8b forming a part of the soft water discharge pipe 8. Branch pipes 81, 82, 83 are arranged, and second branch pipes 74, 75 branching from the first branch pipe 7 a of the treated water introduction pipe 7 are arranged in the second water flow chamber 2, and the first connection pipe 2nd branch piping 84 and 85 connected to 8a is arranged. The first connection pipe 8a and the second connection pipe 8b are connected in parallel by the connection pipe 8c. In the connection regeneration piping system Y, a regenerant introduction pipe 9 sharing a part of the treated water introduction pipe 7 is arranged, and the branch pipes 71, 72, 73 are shared as branch pipes of the regenerant introduction pipe 9 and branched. The pipes 81, 82, 83 are shared as the intermediate regenerant discharge pipe, the branch pipes 84, 85 are shared as the branch pipe for the intermediate regenerant introduction pipe, and the second branch pipes 74, 75 are connected to the regenerant discharge pipe 11. Shared as branch piping. Further, in order to partition the soft water sampling piping system X and the regeneration piping system Y, the first branch piping 7a that branches the valve a to the treated water introduction piping 7 from the upstream side of the valve a in the treated water introduction piping 7. The upstream side of the regenerant discharge pipe 11 is the valve b, the downstream side of the regenerant discharge pipe 11 is the valve e, the soft water discharge pipe 8 is connected to the first connection pipe 8a downstream of the valve c, and the regenerant supply pipe 9 A valve d is arranged on the upstream side. Further, the regenerant discharge pipe 11 and the anode chamber introduction pipe 17 are connected, and the cathode chamber introduction pipe 13 and the anode chamber discharge pipe 12 are connected.

  A monovalent cation salt supply means may be connected to the regenerant introduction pipe 9 of the softening device 10 (not shown). Thereby, the monovalent cation concentration in the substitution water can be appropriately adjusted to an arbitrary amount. Examples of the monovalent cation salt supply means include a device composed of a monovalent cation salt storage tank, a monovalent cation salt supply pump, piping, valves and the like.

  Although the monovalent cation selective permeable membrane 4 is not particularly limited, a cation exchange membrane in which a thin layer of polycation is completely fixed on the membrane surface can be used. Since the electrostatic repulsion between the polycation, which is a positively charged barrier existing on the membrane surface, and the ion to be permeated is larger for the divalent cation than for the monovalent cation, Permeation of the membrane is hindered. As such a monovalent cation selective permeable membrane, a commercially available one can be used.

  In the softening device 10, the soft water sampling piping system X and the regeneration piping system Y use common piping, but the present invention is not limited to this, and the soft water sampling piping system X and the regeneration piping system Y are completely separated. A pipe system may be used, and a form using a common pipe that is different from the pipe system shown in FIG.

  Next, a method for producing soft water using the softening device 10 and regenerating the cation exchange resin will be described. In the water sampling step, the water to be treated containing the hardness component is positioned on the cathode side of the monovalent cation selective permeation membrane on the anode side of the monovalent cation selective permeation membrane and the water to be treated containing the hardness component in a state where no direct current is applied. This is a step of obtaining soft water by passing water through the second water passage chamber. In this example, the water to be treated containing a hardness component is passed through both the first water passage chamber 1 and the second water passage chamber 2 in parallel. That is, in the water sampling process in FIG. 1, the valves a to c are opened and the valves d and e are closed. Next, the water to be treated is caused to flow into the first water flow chamber 1 and the second water flow chamber 2 through the water to be treated introduction pipe 7, the branch pipes 71 to 73, the first branch pipe 7 a and the branch pipes 74 and 75. Soft water is obtained through 81 to 85, the first connection pipe 8a, the connection pipe 8c, the second connection pipe 8b, and the soft water discharge pipe 8. In the 1st water flow chamber 1 and the 2nd water flow chamber 2, since it softens by the substitution reaction similar to what is called salt softening using Na type | mold cation exchange resin tower, compared with the electrosoftening by continuous electricity supply, substitution efficiency Higher and lower hardness treated water can be obtained. Moreover, since the to-be-processed water is water-passed in parallel with the 1st water flow chamber 1 and the 2nd water flow chamber 2, the water flow chamber volume at the time of water sampling becomes large, and a water sampling flow volume can be increased. The end of the water sampling process is determined by a certain time calculated from the hardness of the water to be treated, the flow rate of the water to be treated, the filled cation exchange capacity in the apparatus, or a certain amount of water collected, or the hardness measurement at the outlet of the treated water It is determined when the value exceeds a certain value.

  A regeneration process is performed after the water sampling process. In the regeneration step, regenerated water containing monovalent cations is applied in series from the first water flow chamber 1 to the second water flow chamber 2 in a state where a direct current is applied, and in the first water flow chamber 1 and the second water flow chamber. The energizing step of regenerating the cation exchange resin 19 by passing water so that the flow direction in 2 is counter-current, and passing the water to be treated without applying a direct current as in the water sampling step, It consists of extruding and rinsing high-concentration recycled water. That is, in the energization process of the regeneration process in FIG. 2, the valves d and e are opened and the valves a to c are closed. Next, the regenerant containing the monovalent cation salt is changed into a regenerant introduction pipe 9, branch pipes 71 to 73, first water passage chamber 1, branch pipes 81 to 83, first connection pipe 8a, connection pipe 8c, and second connection. Water is passed through the pipe 8b, the branch pipes 84 and 85, the second water passage chamber 2, the branch pipes 74 and 75, and the regenerant discharge pipe 11 in this order.

In the present invention, sodium chloride is suitable as the monovalent cation salt, and the regenerant is preferably used as a saline solution. In the regenerant, the monovalent cation concentration is 100 to 1000 mg CaCO ₃ / l. If the monovalent cation concentration is too low, it is not preferable from the viewpoint that the regeneration efficiency is lowered, and if it is too high, the amount of the regenerative agent used is increased but the effect is not improved.

  In the energization process of the regeneration process, by passing water in series from the first water passage 1 to the second water passage 2, the hardness component remains in the second water passage 2 and monovalent cations are reduced. It is in a state to go. However, since the hardness component is higher in charge than the monovalent cation and easily moves, the hardness component substituted with the regenerant is on the discharge side in the second water flow chamber 2 adjacent to the inflow side of the first water flow chamber 1. Will move. For this reason, it discharges | emits from the system from the 2nd water passage 2 rapidly. Therefore, both the cation exchange resins in the first water flow chamber 1 and the second water flow chamber 2 can be returned to the original sodium type in the same state, and the transition to the water sampling process becomes smooth (see FIG. 7). ). On the other hand, in the energization process of the regeneration process, since the monovalent cation is returned from the downstream second water flow chamber to the upstream first water flow chamber, the monovalent cation concentration in the system can be kept high, and the added monovalent cation. Significant savings in cationic salts. In addition, at the time of regeneration, the flow direction of the first water passage chamber 1 and the second water passage chamber 2 is not particularly limited, and may be a countercurrent or a parallel flow.

Suitable operating conditions in the energizing process of the regeneration process are those that satisfy R ≦ 1. R is (current value (A) × 3600 sec / 96500 coulomb) / ((monovalent cation concentration of regenerant (mgCaCO ₃ / l) × regenerant flow rate (l / h)) / number of second water flow chambers) ). When R exceeds 1, that is, when a current exceeding a monovalent cation is passed, the monovalent cation becomes insufficient, and water deviates between H ⁺ and OH ⁻ . In this case, although H ⁺ permeates the monovalent cation selective permeation membrane, OH ⁻ remains, so that the pH becomes high and the membrane surface on the cathode side of the second water passage can be easily scaled. A practical R value is 0.7 to 0.9. When R is less than 0.7, the reproduction time becomes long, which is not preferable.

  In the softening device 10, the regenerant (regenerated waste liquid) outlet water discharged from the second water passage 2 is passed through the anode chamber 6, and the anode chamber outlet water is further passed through the cathode chamber 5. As a result, the monovalent cation that has passed through the cation exchange membrane 3 from the first water flow chamber 1 and moved to the second water flow chamber 2 can be returned to the anode chamber 6 and used again for regeneration. By passing the anode outlet water whose pH is lowered due to movement and reduction of cations in the cathode chamber 5, the risk of hardness scale deposition in the cathode chamber 5 can be reduced. In this example, all of the second water passage outlet water is passed through the anode chamber 6, but the present invention is not limited to this, and part of the second water passage outlet water is passed through the anode chamber 6. The electrode water in the anode chamber 6 and the cathode chamber 5 may be separately passed.

  In the softening device 10, the cathode outlet water discharged from the cathode water discharge pipe 14 is used as alkaline functional water having a reducing power because cations increase and pH rises and hydrogen gas is generated by the cathode reaction. Can do.

  The end of the energization process of the regeneration process is determined by a fixed time calculated from the concentration of the monovalent cation of the regenerant and the flow rate of the regenerant, the charged cation exchange capacity in the apparatus, or a constant water flow rate, or the regenerant It is determined when the hardness measurement value at the outlet of the discharge pipe (cathode chamber outlet or anode chamber outlet) falls below a certain value. After the energization process of the regeneration process, the treated water is passed through the first water flow chamber 1 and the second water flow chamber 2 without applying a direct current in the same manner as the water sampling process, and a high concentration regenerant is added. Extrude and rinse. The end of the non-energization process of the regeneration process is determined by a certain amount of time determined empirically, a certain amount of water flow, or the conductivity of the treated water outlet. This completes the regeneration process.

  In the present invention, if a plurality of softening devices 10 are connected in parallel and operated such that the water sampling step and the regeneration step are alternately performed between the devices, water can be collected substantially continuously. The switching timing between the water sampling process and the regeneration process may be based on the judgment value at the end of the water sampling process and the regeneration process. When the reproduction time can be long, reproduction can be performed with a lower current value, for example, R <0.5, and the capacity of the DC power supply can be reduced.

  A softening device according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4 are schematic diagrams of the softening device of this example. FIG. 3 shows a flow chart for carrying out a water sampling process, and FIG. 4 shows a flow chart for carrying out a regeneration process. In the softening device 10a of FIG. 3, the same components as those of the softening device 10 of FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. That is, the softening device 10a is different from the softening device 10 in that the flow directions of the first water flow chamber 1 and the second water flow chamber 2 are the same direction and upward flow.

  That is, in the softening device 10a of FIG. 3, in the soft water sampling piping system X, branch piping 71, 72, 73 branched from the to-be-treated water introduction piping 7 is arranged in the 1st water flow chamber 1, and 2nd connection piping is provided. Branch pipes 81, 82, 83 connected to 8b are arranged, and second branch pipes 74, 75 branched from the first branch pipe 7a of the treated water introduction pipe 7 are arranged in the second water flow chamber 2, 2nd branch piping 84 and 85 connected to 1 connection piping 8a is arranged. The first connection pipe 8a is a part of the soft water drain pipe 8, and the first connection pipe 8a and the second connection pipe 8b are connected in parallel by the connection pipe 8c. In the regeneration pipe system Y, the second connection pipe 8b is shared as the regeneration agent introduction pipe, and the downstream end of the treated water introduction pipe 7 and the upstream end of the first connection pipe 8a are connected to form an intermediate regeneration agent introduction pipe 9a. The second branch pipes 84 and 85 are shared as intermediate regenerant introduction branch pipes, and the second branch pipes 74 and 75 are shared as branch pipes connected to the regenerant discharge pipe 11. Further, in order to partition the soft water sampling piping system X and the regeneration piping system Y, the first branch piping 7a that branches the valve a to the treated water introduction piping 7 from the upstream side of the valve a in the treated water introduction piping 7. Of the recycle waste liquid discharge pipe 11, the valve e is downstream of the connection pipe 8c in the soft water discharge pipe 8, and the valve d is connected to the intermediate regenerant introduction pipe 9a. Are arranged on the upstream side of the junction of the connection pipe 8c in the regenerant introduction pipe 8b.

  Next, a method for producing soft water using the softening device 10a and regenerating the cation exchange resin will be described. As in the softening device 10, the water sampling step is a step of passing water to be treated containing hardness components in parallel to both the first water flow chamber 1 and the second water flow chamber 2 without applying a direct current. It is. That is, in the water sampling process in FIG. 3, the valves a to c and f are opened, and the valves e, d and g are closed. Next, the water to be treated is caused to flow into the first water flow chamber 1 and the second water flow chamber 2 through the water to be treated introduction pipe 7, the first branch pipe 7 a and the branch pipes 71 to 75, and the branch pipes 81 to 85, the second pipe. Soft water is obtained through the connection pipe 8b, the connection pipe 8c, the first connection pipe 8a, and the soft water discharge pipe 8. In the water sampling process in the softening device 10a, the operations in the first water flow chamber 1 and the second water flow chamber 2 are the same as those in the water sampling process of the softening device 10.

  In the energization process of the regeneration process, as shown in FIG. 4, the valves d, e and g are opened, and the valves a to c and f are closed. Subsequently, the regenerant containing the monovalent cation salt is changed into a regenerant introduction pipe 9, branch pipes 81 to 83, a first water flow chamber 1, branch pipes 71 to 73, treated water introduction pipe 7, and intermediate regenerant introduction pipe 9a. The first connection pipe 8a, the branch pipes 84 and 85, the second water flow chamber 2, the branch pipes 74 and 75, and the regenerant discharge pipe 11 are passed in this order.

  According to the regeneration process of the softening device 10a, in addition to the same effects as the regeneration process of the softening device 10, the flow directions of the first water flow chamber 1 and the second water flow chamber 2 are opposite in the water sampling process and the regeneration process. Because of the orientation, substitution of the cation exchange resin is effectively performed. Further, compared with the softening device 10, the replacement efficiency at the time of regeneration is good, but the intermediate regenerant discharging / introducing part is somewhat complicated.

  A softening device according to a third embodiment of the present invention will be described with reference to FIGS. 5 and 6 are schematic diagrams of the softening device of this example. FIG. 5 shows a flow chart for carrying out the water sampling process, and FIG. 6 shows a flow chart for carrying out the regeneration process. In the softening device 10a of FIG.5 and FIG.6, the same code | symbol is attached | subjected to the same component as the softening device 10 of FIG. 1, the description is abbreviate | omitted, and a different point is mainly demonstrated. That is, the softening device 10b is different from the softening device 10 in the flow direction of the water to be treated in the soft water sampling process, that is, the soft water sampling piping system X.

  In the soft water sampling pipe system X of the softening device 10b, branch pipes 71 and 72 and intermediate soft water discharge pipes 73 and 74 branched from the treated water introduction pipe 7 are arranged in the second water flow chamber 2, and the first water flow. In the chamber 1, intermediate soft water introduction pipes 81 to 83 are arranged, and branch pipes 84 to 86 connected to the soft water discharge pipe 8 are arranged. The first connection pipe 8b to which the intermediate soft water discharge pipes 73 and 74 are connected and the second connection pipe 8a to which the intermediate soft water introduction pipes 81 to 83 are connected are connected in series by a connection pipe 8c. In the regeneration pipe system Y, the soft water discharge pipe 8 is commonly used as the regenerant introduction pipe 9, the branches 84 to 86 are commonly used as the regenerant introduction pipe, and the branch pipes 81 to 83 are commonly used as the intermediate regenerant discharge pipe. The pipes 73 and 74 are shared as intermediate regenerant introduction pipes, and the branch pipes 71 and 72 are shared as regenerant discharge pipes. The regenerant discharge pipes 71 and 72 are connected to the regenerant discharge pipe 11. Further, in order to partition the soft water sampling piping system X and the regeneration piping system Y, a valve a is arranged on the upstream side of the treated water introduction pipe 7, and a valve b is arranged on the downstream side of the soft water discharge pipe 8. A valve d is disposed upstream of the regenerant introduction pipe 9 and a valve c is disposed downstream of the regenerant discharge pipe 11.

  Next, a method for producing soft water using the softening device 10b and regenerating the cation exchange resin will be described. In the water sampling step, the water to be treated containing a hardness component is transferred from the second water flow chamber 2 located on the anode side 16 of the monovalent cation selective permeable membrane 4 to the monovalent cation selective permeable membrane 4 without applying a direct current. This is a step of obtaining soft water by passing water in series in this order through the first water flow chamber 1 located on the cathode 15 side. That is, in the water sampling step in FIG. 5, the valves a and b are opened and the valves c and d are closed. Next, the water to be treated is treated water introduction pipe 7, branch pipes 71 and 72, second water flow chamber 2, intermediate soft water discharge pipes 73 and 74, first connection pipe 8a, connection pipe 8c, second connection pipe 8b, Water is passed through the branch pipes 81 to 83, the first water flow chamber 1, the branch pipes 84 to 86, and the soft water discharge pipe 8 in this order. According to the regeneration process of the softening device 10b, in addition to the same effects as the regeneration process of the softening device 10, the water sampling process can reduce the water flow rate and extend the water flow time compared to parallel water flow.

  In the softening device 10b, in the energization process of the regeneration process, the valves d and c are opened, and the valves a and b are closed. Next, the regenerant containing the monovalent cation salt is regenerated as a regenerant introduction pipe 9, branch pipes 84 to 86, a first water passage 1, an intermediate regenerant discharge pipe 81 to 83, a second connection pipe 8b, a connection pipe 8c, Water is passed through the first connection pipe 8a, the intermediate regenerant introduction pipes 73 and 74, the second water flow chamber 2, the branch pipes 71 and 72, and the regenerant discharge pipe 11 in this order.

  According to the regeneration process of the softening device 10b, in addition to the same effects as the regeneration process of the softening device 10, it can be performed with an apparatus that uses a small number of valves. Further, in each water flow direction, the flow direction is opposite between the sampling time and the regeneration time, so that the replacement efficiency during the regeneration is improved.

  Further, in the softening devices 10 to 10b, the regenerant waste water may be introduced into the cathode chamber 5, and then the discharged water from the cathode chamber 5 may be introduced into the anode chamber 6. As a result, the monovalent cations that have migrated from the first water flow chamber 1 through the cation exchange membrane 3 can be returned to the uppermost anode chamber 6 for cation migration and used again for regeneration. As a result, since the monovalent cation concentration in the system can be maintained high, the monovalent cation salt added to the reclaimed water can be saved and the softening efficiency can be increased. In addition, the anode outlet water of the regenerant can be used as acidic functional water because the cation is reduced to lower the pH, and hypochlorous acid is generated by the anodic reaction and has oxidizing power and sterilizing power.

  Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.

The treated water was passed through the softening apparatus shown in FIGS. 1 and 2 under the operating conditions shown in Table 1 to obtain treated water. Water to be treated was passed through tap water through an activated carbon filter (PF-CB, manufactured by Organo Corporation) into the first water passage and the second water passage of the softening device. The results are shown in Table 1. The treated water sample and operation data were collected 5 minutes before switching from the water sampling process to the regeneration process. In addition, the water sampling step was a step of passing the water to be treated in a non-energized state in parallel to the first water passage and the second water passage, and the time was 12 hours. In the regeneration step, the regenerant is passed through the first water passage from the first water passage to the second water passage in series in this order, and the treated water is passed through the non-energized water in the same manner as the water sampling step. The process consisted of a process of extruding and rinsing reclaimed water having a high concentration, and the times were 10 hours and 15 minutes, respectively. Reclaimed water used for regeneration was filtered with activated carbon filtration filter, and 25% saline was added using a metering pump so that the alkali metal concentration was 360 mgCaCO ₃ / L, as was treated water.

Comparative Example 1
The treated water was passed through a softener (“SAT-105B”; manufactured by Organo Corporation) under the conditions shown in Table 1 to obtain treated water. The results are shown in Table 1. The treated water was tap water that was passed through an activated carbon filter and passed through a softener, and the treated water sample and operation data were collected 5 minutes before switching from the water sampling process to the regeneration process. The water sampling step was a step of passing the treated water through the cation exchange resin, and the time was 12 hours. The regeneration process is a process in which the replacement water (regeneration agent) shown in Table 1 is passed through a cation exchange resin to be replaced with Na form. In the softener used, the conditions in Table 1 are automatically set by the mechanism inside the apparatus. It is configured to allow medication and rinse. Also in Comparative Example 1, the regeneration process was automatic operation, and the amount of salt used was calculated from the prescribed amount of salt used for regeneration.

  As is clear from Table 1, in the regeneration process of Example 1, the monovalent cation concentration in the system is kept high in order to return the monovalent cation from the second water passage downstream to the first water passage upstream. Compared with a conventional salt regeneration softener, the amount of the monovalent cation salt to be added can be reduced to about 1/3 per regeneration.

It is a schematic diagram of the softening apparatus in the 1st Embodiment of this invention, and is a flowchart which implements a water sampling process. It is a schematic diagram of the softening apparatus in the 1st Embodiment of this invention, and is a flowchart which implements a reproduction | regeneration process. It is a schematic diagram of the softening apparatus in the 2nd Embodiment of this invention, and is a flowchart which implements a water sampling process. It is a schematic diagram of the softening apparatus in the 2nd Embodiment of this invention, and is a flowchart which implements a reproduction | regeneration process. It is a schematic diagram of the softening apparatus in the 3rd Embodiment of this invention, and is a flowchart which implements a water sampling process. It is a schematic diagram of the softening apparatus in the 3rd Embodiment of this invention, and is a flowchart which implements a reproduction | regeneration process. It is a figure explaining the movement of the cation in the reproduction | regeneration process of the softening apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Softening chamber 2 Replacement chamber 3 Cation exchange membrane 4 Monovalent cation selective permeation membrane 5 Cathode chamber 6 Anode chamber 15 Cathode 16 Anode 10, 10a, 10b Electrosoftening device X Soft water sampling piping system Y Regeneration piping system aj Valve

Claims (9)

  A monovalent cation selective permeable membrane and a cation exchange membrane are alternately arranged between the anode chamber and the cathode chamber, and a water passage chamber filled with a cation exchanger is provided between them, and is located on the cathode side of the monovalent cation selective permeable membrane. The first water flow chamber and the second water flow chamber located on the anode side of the monovalent cation selective permeable membrane are respectively provided with a water introduction path and a discharge path, and each of the anode chamber and the cathode chamber has water. An introduction route and a discharge route are arranged, respectively, and a soft water sampling route for obtaining soft water by passing the water to be treated containing hardness components in parallel to both the first water passage and the second water passage. A softening device is provided, wherein a regeneration path for regenerating the cation exchanger is provided by passing regenerated water containing monovalent cations in series from the first water passage to the second water passage.   A monovalent cation selective permeable membrane and a cation exchange membrane are alternately arranged between the anode chamber and the cathode chamber, and a water passage chamber filled with a cation exchanger is provided between them, and is located on the cathode side of the monovalent cation selective permeable membrane. The first water flow chamber and the second water flow chamber located on the anode side of the monovalent cation selective permeable membrane are respectively provided with a water introduction path and a discharge path, and each of the anode chamber and the cathode chamber has water. An introduction path and a discharge path are arranged, respectively, and a soft water sampling path is provided for obtaining soft water by passing water to be treated containing hardness components from the second water passage in series to the first water passage. A softening device comprising a regeneration path for regenerating the cation exchanger by passing regenerated water containing a valent cation in series from the first water passage to the second water passage.   The discharge path of the second water passage in the regeneration path is connected to the introduction path of the cathode chamber, and the discharge path of the cathode chamber is connected to the introduction path of the anode chamber. The softening device according to claim 1 or 2.   The discharge path of the second water flow chamber in the regeneration path is connected to the introduction path of the anode chamber, and the discharge path of the anode chamber is connected to the introduction path of the cathode chamber. The softening device according to claim 1 or 2.   A monovalent cation selective permeation membrane and a cation exchange membrane are alternately arranged between the anode chamber and the cathode chamber, and a water passage chamber filled with a cation exchanger is provided between them, and includes a hardness component in a state where no direct current is applied. Water sampling step for obtaining soft water by passing water to be treated through the first water passage located on the cathode side of the monovalent cation selective permeable membrane and the second water passage located on the anode side of the monovalent cation selective permeable membrane. And a regeneration process in which regeneration water containing monovalent cations is passed in series from the first water flow chamber to the second water flow chamber to regenerate the cation exchanger while a direct current is applied. A method of operating the softening device.   The operation of the softening device according to claim 5, wherein water to be treated including a hardness component is passed in parallel to both the first water flow chamber and the second water flow chamber during the water sampling step. Method.   6. The method of operating a softening device according to claim 5, wherein, in the water sampling step, water to be treated containing a hardness component is passed in series from the second water flow chamber in the order of the first water flow chamber. .   The all or part of the outlet water discharged from the second water passage chamber is passed through the cathode chamber during the regeneration step, and the cathode chamber outlet water is further passed through the anode chamber. The operating method of the softening apparatus of any one of 5-7.   The all or part of the outlet water discharged from the second water passage during the regeneration step is passed through the anode chamber, and the anode chamber outlet water is further passed through the cathode chamber. The operating method of the softening apparatus of any one of 5-7.

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