JP2012040474A - Method and device for producing pure water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for producing pure water capable of preventing the generation of the occlusion of the electric demineralizing device and the deterioration of water quality of the treating water and capable of preventing the reduction of the treating efficiency of the electric demineralizing device and capable of preventing the shortening of the life of the device.SOLUTION: In the method for producing pure water alternately repeating a pure water producing treatment demineralizing by the electric demineralizing device 14, and a hot water sterilization treatment sterilizing by feeding hot water to the electric demineralizing device 14, the flowing direction of the water to be treated in the condensing chamber 142 of the electric demineralizing device 14 is set to be a countercurrent direction to the flowing direction of the water to be treated in the demineralizing chamber 141 during the pure water producing treatment, and the flowing direction of the water to be treated in the condensing chamber 142 of the electric deionizing device 14 is set to be a concurrent flow direction to the flowing direction of the water to be treated in the demineralizing chamber 141 during the hot water sterilizing treatment.

Description

  The present invention relates to a pure water production method and a pure water production apparatus that alternately perform pure water production treatment and hot water sterilization treatment, and in particular, can prevent a reduction in treatment efficiency of an electrical deionization apparatus and improve the quality of the treated water. The present invention relates to a pure water production method and a pure water production apparatus capable of obtaining excellent pure water.

  Electrodeionization does not require the use of chemicals for regeneration in the regeneration after deionization treatment, unlike conventional ion exchange resins, and does not require labor and equipment for disposal of chemicals. Currently, it has come to be widely used in water treatment used for pharmaceuticals, foods, semiconductor manufacturing and the like.

  In particular, in the production of pure water used for pharmaceuticals and food, strict viable bacteria management is required to supply pure water with higher purity. When performing, the operation is performed while performing the hot water sterilization treatment.

  For example, in an apparatus for producing pure water for pharmaceutical use equipped with an electrical deionizer, deionization is performed by supplying treated water at room temperature, and before the quality of the treated water can be maintained, the electrical deionization is performed. By supplying hot water of 60 ° C. or higher to the ion device and sterilizing, and again supplying normal water to be treated and performing deionization treatment, by alternately performing the pure water production process and the hot water sterilization process The treated water maintaining a predetermined water quality can always be supplied (see, for example, Patent Document 1).

JP 2004-74109 A

However, in such a pure water production method and pure water production apparatus, when normal temperature treated water is supplied after the hot water sterilization treatment, the concentration chamber may be blocked in the electric deionization apparatus.
When the concentrating chamber is clogged, there is a problem that the flow rate of the concentrated water decreases and the processing cost cannot be met, or the life of the electric deionization apparatus is shortened. In addition, the ion removal performance of the ion exchange membrane is lowered, and there may be a problem that the treated water conductivity from the electric deionization device does not conform to the pharmaceutical pure water standard.

In addition, as an electric deionization device, a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between electrode chambers (cathodes and anodes) to form concentration chambers and demineralization chambers alternately. What performs ion treatment while passing water through a chamber, a desalting chamber, and an electrode chamber is known.
The treated water supplied to the electric deionizer is desalted while passing through the desalting chamber, and the treated water is supplied to the subsequent apparatus. On the other hand, in the electric deionization apparatus, ions or the like separated from the water to be treated move to the concentration chamber through the ion exchange membrane and are discharged out of the system of the deionization apparatus.

However, in the above electric deionization apparatus, the ion concentration of the water to be treated is high near the entrance of the desalination chamber. Therefore, if the water to be treated in this region moves to the concentration chamber side, high-concentration ion water accumulates in the concentration chamber. There are things to do. In this case, there is a problem that clogging occurs in the concentration chamber or the quality of the treated water discharged from the concentration chamber deteriorates.
In order to solve such a problem, a deionization method has been proposed in which deionization is performed by passing water in the concentrating chamber in a direction opposite to the direction of water flow in the desalting chamber.

When the above water flow method is adopted, the high-concentration treated water flowing into the concentration chamber from the desalination chamber inlet side is immediately discharged from the concentration chamber outlet. Accordingly, accumulation of ions and the like in the vicinity of the concentration chamber outlet is prevented, and clogging in the concentration chamber and deterioration of the quality of the treated water can be suppressed.
However, when such a water flow system is adopted, the pressure difference between the desalting chamber inlet and the concentration chamber outlet becomes excessive, and the ion exchange membrane between the desalting chamber and the concentration chamber is likely to be deformed. In this case, the concentrating chamber is blocked, and there is a problem that the above-described decrease in the concentration water flow rate, increase in the treated water conductivity, and the like become significant.

  Therefore, the present invention has been made in view of such a conventional problem, and in a pure water production apparatus and a pure water production method having a hot water sterilization treatment step, clogging of an electric deionization apparatus or treated water is generated. An object of the present invention is to provide a pure water production method and a production apparatus capable of preventing deterioration of water quality and preventing reduction in processing efficiency of an electric deionization apparatus and shortening of life of the apparatus.

  The present inventors have found that the above problems can be solved by the pure water production method and the pure water production apparatus of the present invention, and have completed the present invention.

  That is, the pure water production method of the present invention alternately performs a pure water production process in which deionization is performed by an electric deionization apparatus and a hot water sterilization process in which hot water is supplied to the electric deionization apparatus to sterilize. In the pure water production process, the flow direction of the water to be treated in the concentration chamber of the electric deionization apparatus during the pure water production process is the flow direction of the water to be treated in the demineralization chamber The flow direction of the water to be treated in the concentrating chamber of the electric deionizer during the hot water sterilization treatment is parallel to the flow direction of the water to be treated in the demineralization chamber. It is characterized by the flow direction.

  Further, the pure water production apparatus of the present invention is an electric deionization apparatus in which a plurality of anion exchange membranes and cation exchange membranes are arranged between a cathode and an anode to form a demineralization chamber and a concentration chamber. A pure water production apparatus that alternately performs pure water production treatment and hot water sterilization treatment, wherein the electric deionization device is disposed at the demineralized water outlet of the demineralization chamber during the pure water production treatment. The treated water is introduced into the concentrating chamber from the near side, and the concentrated water is allowed to flow out from the side of the concentrating chamber close to the treated water inlet of the desalting chamber. Control means for introducing treated water into the concentrating chamber from the side close to the treated water inlet of the water and allowing the concentrated water to flow out from the side of the concentrating chamber close to the desalted water outlet. It is what.

According to the present invention, in the electric deionization apparatus, water to be treated having a high ion concentration is immediately discharged even if it is supplied from the demineralization chamber to the concentration chamber. Deterioration of water quality is suppressed.
In addition, according to the present invention, the flow direction of the concentrating chamber is switched between the hot water sterilization process and the pure water production process. There is no short-lived life.

  As described above, according to the present invention, in the pure water production method and the pure water production apparatus having the hot water sterilization treatment step, the electrical deionization apparatus is deteriorated due to the clogging of the concentration chamber, or the quality of the concentrated water is deteriorated. In addition, it is possible to prevent the processing efficiency from decreasing due to the blockage of the concentration chamber and the shortening of the life of the electric deionization apparatus.

It is a figure which shows schematic structure of the pure water manufacturing apparatus in one Embodiment of this invention. It is a figure which expands and shows the structure of the electrical deionization apparatus 14 periphery of the pure water manufacturing apparatus in one Embodiment of this invention. It is a figure explaining the flow around the electric deionization apparatus in the pure water manufacturing method of this invention. It is a figure which shows the pressure state of the to-be-processed water and treated water of the demineralization chamber of an electric deionization apparatus at the time of a pure water manufacturing process, and a concentration chamber. It is a figure which shows the pressure state of the to-be-processed water and treated water of the demineralization chamber of the electric deionization apparatus at the time of a heat sterilization process, and a concentration chamber. It is a figure which shows the flow of the pure water manufacturing process process of the pure water manufacturing method of this invention. It is a figure which shows the flow in the temperature rising process of the pure water manufacturing method of this invention. It is a figure which shows the flow in the temperature equalization process of the pure water manufacturing method of this invention. It is a figure which shows the flow in the temperature fall process of the pure water manufacturing method of this invention. It is a figure explaining the processing flow of the pure water manufacturing method in other embodiments.

  The details of the present invention as well as other features and advantages are described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a pure water production apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the pure water production apparatus 1 according to the present embodiment includes an activated carbon adsorption device 11 that treats pretreated water 10, and a raw water tank 12 that is disposed downstream of the activated carbon adsorption device 11. The adsorber 11 and the raw water tank 12 are connected by a supply pipe L1 provided with an opening / closing valve B1.
A reverse osmosis membrane device 13 and an electrical deionization device 14 are sequentially installed in the subsequent stage of the raw water tank 12, and a treated water tank 15 is installed in the subsequent stage of the electrical deionization device 14. Yes. The raw water tank 12 and the reverse osmosis membrane device 13 and the reverse osmosis membrane device 13 and the electrical deionization device 14 are connected by a pipe L1-1 and a pipe L1-2, respectively. Furthermore, the electrical deionizer 14 and the treated water tank 15 are connected by a supply pipe L2 having an opening / closing valve B2. The on-off valve B2 also functions as a first pressure adjustment valve.
A steam heater 16 is provided between the raw water tank 12 and the reverse osmosis membrane device 13. In FIG. 1, the steam heater 16 is installed between the raw water tank 12 and the reverse osmosis membrane device 13, but is not particularly limited, and heating is not limited to the steam heater but an electric heater or the like Can also be used.
Although not shown in the present embodiment, a membrane treatment device for removing turbidity may be installed in the previous stage of the activated carbon adsorption device 11 or in the previous stage of the reverse osmosis membrane device 13, and the reverse osmosis is further performed. Between the membrane device 13 and the electric deionization device 14, a hardness removing device for removing a hardness component that could not be removed by the reverse osmosis membrane device 3 may be installed.

  The concentrated water outlet pipe of the reverse osmosis membrane device 13 is connected to the concentrated water discharge pipe L3 via the concentrated water discharge valve B3. Between the upstream portion of the concentrated water discharge valve B3 of the concentrated water discharge pipe L3 and the raw water tank 12, in the soaking process described later, the concentrated water discharge valve B3 is closed and the switching valve B4 provided in the pipeline is opened, A reflux pipe L4 for returning the concentrated water of the reverse osmosis membrane device 13 to the raw water tank 12 is provided.

The electric deionization apparatus 14 includes a demineralization chamber 141, a concentration chamber 142, and an electrode chamber 143. A sterilization step is provided between the upstream portion of the open / close valve B2 of the demineralized water supply pipe L2 and the raw water tank 12. , A recirculation pipe L5 for recirculating high-temperature demineralized water to the raw water tank 12 by opening the switching valve B5 is provided. The switching valve B5 also functions as a second pressure adjustment valve.
Further, a pipe L6 is provided at the raw water tank 12 side entrance of the concentrating chamber 142, and a pipe L7 is provided at the treated water tank 15 side entrance of the concentrating chamber 142. In the present embodiment, by the configuration described in detail later, the water to be treated can be supplied from the pipe L6 to the concentrating chamber 142 and the water to be treated can be supplied from the pipe L7 to the concentrating chamber 142.

A first pump P1 is provided in the pipe between the raw water tank 12 and the steam heater 16, and a second pump P2 is provided in the pipe between the steam heater 16 and the reverse osmosis membrane device 13. It has been.
Water in the raw water tank 12 is sequentially passed through the above devices by these pumps, and hot water is circulated in the system through a reflux pipe during heat sterilization as will be described later. In FIG. 1, a first pump P1 is inserted between the raw water tank 12 and the steam heater 16, and a second pump P2 is interposed between the steam heater 16 and the reverse osmosis membrane device 13. Although it is inserted, any one may be sufficient and the place to install is not specifically limited.
Thermometers T1, T2, and T3 are provided in the raw water tank 12, the pipe between the steam heater 16 and the reverse osmosis membrane device 13, and the pipe between the electrical deionizer 14 and the treated water tank 15, respectively. At the time of heat sterilization, the temperature of each part is detected, and the control means (not shown) is used to operate each valve in each step of temperature increase, temperature equalization, and temperature decrease, and to control the steam heater 16. Thus, the water temperature of each part is maintained at a predetermined sterilization temperature.

  As described above, the thermometers T1 to T3 monitor that the water temperature in the system is the predetermined sterilization temperature during the heat sterilization, and the steam heater 16 is controlled by a control unit (not shown) so as to maintain the predetermined sterilization temperature. It is used as a temperature sensor for feedback control.

The reverse osmosis membrane device 13 used in the present invention preferably has a permeated water conductivity of 45 μS / cm or less when hot water having a water temperature of 60 ° C. or more is passed, and the desalination rate is 85% or more. Are preferred.
Examples of the reverse osmosis membrane 131 (not shown) attached to the reverse osmosis membrane device 13 include, for example, Duratherm RO 2540 HF (for 70 ° C), Duratherm RO 4040 HF (for 70 ° C), Duratherm RO 8040 HF ( 70 ° C.) (both manufactured by US GE, trade name) and the like.

FIG. 2 is an enlarged view showing a configuration around the electrical deionization device 14 of the pure water production apparatus according to the embodiment of the present invention.
As shown in FIG. 2, the electric deionization apparatus 14 is composed of a demineralization chamber 141, a concentration chamber 142, and an electrode chamber 143. A pipe L7 is connected to a pipe L8 provided with an opening / closing valve B6, and Q1. In addition, the electrode water outlet pipe of the electrode chamber 143 is also connected to a pipe L9 provided with an opening / closing valve B7.
The pipes L8 and L9 are respectively connected to a common reflux pipe L10, the reflux pipe L10 is branched, one branch pipe L10-1 is connected to the raw water tank 12, and the other branch pipe L10-2 is Open to the concentrated water outlet. The branch pipes L10-1 and 10-2 are provided with valves B8 and B9 for switching the flow path to the raw water tank 12 side and the concentrated water discharge port side, respectively.

A branch pipe L11 having an opening / closing valve B10 is provided between the reverse osmosis membrane device 13 and the desalting chamber 141 (Q3) and behind the concentration chamber 142, and the end of the branch pipe L11 on the treated water tank 15 side. Is connected to the pipes L7 and L8 in Q1. The reflux pipe L11, the pipe L7, and the pipe L6 form a first supply / discharge line to the concentration 142.
Further, a branch pipe L12 provided with a switching valve B11 is provided from a position (Q4) upstream of the valve B10 of the branch pipe L11. The branch pipe L12 is a discharge pipe L13 provided with an opening / closing valve B12 at Q2. Connected with. The branch pipe L11, the branch pipe L12, the pipe L6, and the pipe L7 form a second supply / discharge line to the concentration chamber 142.
The switching valve B11 also functions as a third pressure adjustment valve.

1 and 2, the on-off valves (B1, B2, B6, B7, B10, B12), the concentrated water discharge valve (B3), and the switching valves (B4, B5, B8, B9, B11) are heat-treated. In each stage of the pure water production process, the opening and closing is performed by a control means (not shown).
The on-off valve B2 and the switching valve B5, the on-off valve B10 and the switching valve B11, the concentrated water discharge valve B3 and the switching valve B4, and the switching valves B8 and B9 are respectively controlled to open and close at the same time. Is switched.
Moreover, FIG.1 and FIG.2 is one Embodiment of this invention, In the range which does not inhibit the effect of this invention, it can change suitably to the structure used as a pure water apparatus.

Next, based on FIG. 3 (a) and (b), the flow in the periphery of an electrical deionization apparatus of the pure water manufacturing method by the manufacturing apparatus 1 of this invention is demonstrated.
Fig.3 (a) is a figure explaining the flow around an electric deionization apparatus at the time of the pure water manufacture of the pure water manufacturing method of this invention.
In FIG. 3A, the on-off valve B6 and the switching valve B11 are closed and the on-off valves B7, B10, B12 are opened to drive the pump P1 (not shown).
As a result, the raw water is supplied from the pre-stage apparatus side (pretreated water 10, raw water tank 12, and reverse osmosis membrane apparatus 13 in FIG. 1) to the electric deionization apparatus 14 side, and among these, the pipe L1 passes through Q3. The treated water supplied from -2 to the desalting chamber 141 is desalted and then supplied from the supply pipe L2 to the subsequent apparatus side.
On the other hand, the water to be treated that flows from the point Q3 to the reflux pipe L11 side flows into the pipe L7 through the valve B10, and flows into the concentration chamber 142 from the inlet / outlet of the concentration chamber 142 on the treated water tank side. For this reason, the water to be treated in the concentration chamber 142 moves in the direction opposite to the moving direction of the water to be treated in the desalting chamber 141.
The treated water that has passed through the concentrating chamber 142 is discharged from the inlet / outlet of the concentrating chamber 142 on the raw water tank 12 side, and is discharged from the piping L6 and the discharging piping L13 to the drain side through the open / close valve B12.
In addition, the electrode water from the electrode chamber 143 is also discharged to the drain side through the open / close valve B7 by the pipe L9.

Thus, at the time of pure water production processing, the water to be treated in the concentrating chamber 142 is moved in the direction opposite to the moving direction of the water to be treated in the desalting chamber 141, thereby providing an inlet (supply port) in the desalting chamber 141. ) Is adjacent to the outlet (exhaust port) in the concentrating chamber 142. That is, the high-ion-concentrated water present near the inlet of the desalting chamber 141 is quickly discharged from the outlet of the concentrating chamber 142 when it moves to the concentrating chamber 142 side. Accordingly, impurities such as ions do not accumulate in the concentration chamber 142, and clogging or the like in the concentration chamber 142 can be prevented.
Further, as described above, the raw water tank 12 of the desalting chamber 141 and the concentrating chamber 142 is moved by moving the water to be processed in the concentrating chamber 142 in the direction opposite to the moving direction of the water to be processed in the desalting chamber 141. The pressure difference between the side inlets and outlets can be increased.
FIG. 4 is a diagram showing pressure states of water to be treated and treated water in a demineralization chamber and a concentrating chamber of an electric deionization apparatus during a pure water production process.
In this way, the pressure difference between the inlet and outlet of the raw water tank 12 in the desalting chamber 141 and the concentrating chamber 142 is increased, so that the yield at the time of producing pure water can be increased without extremely increasing the pressure by the pressure regulating valve. Can be improved.

FIG.3 (b) is a figure explaining the flow around an electric deionization apparatus at the time of the hot water sterilization of the pure water manufacturing method of this invention.
In FIG. 3B, the on-off valves B10 and B12 are closed, the switching valve B11 and the on-off valve B6 are opened, and the on-off valve B7 is left open, and the pump P1 (not shown) is driven.
Thereby, raw | natural water is supplied to the deionization apparatus 14 side from the front | former stage apparatus side. Among these, the water to be treated supplied from the pipe L1-2 to the desalting chamber 141 via Q3 is supplied to the downstream apparatus side from the supply pipe L2 after being desalted.
On the other hand, the water to be treated which has flowed from the pipe L1-2 to the reflux pipe L11 side through Q3 flows into the pipe L6 from the pipe L12 via the valve B11, and is concentrated from the raw water tank 12 side inlet / outlet of the concentrating chamber 142. It flows into the chamber 142. For this reason, the water to be treated in the concentration chamber 142 moves in parallel with the movement direction of the water to be treated in the desalting chamber 141.
The treated water that has passed through the concentrating chamber 142 is discharged from the inlet / outlet of the concentrating chamber 142 on the treated water tank 15 side, and is discharged from the pipes L7 and L8 to the drain side through the valve B6.
Moreover, the electrode water from the electrode chamber 143 is discharged | emitted by the piping L9 to the waste_water | drain side via the on-off valve B7 similarly to the time of a pure water manufacturing process.

Thus, at the time of the hot water sterilization treatment, by switching the direction of movement of the water to be treated in the concentration chamber 142 to a direction parallel to the direction of movement of the water to be treated in the desalination chamber 141 by the switching operation of the valve, The pressure difference between the concentration chamber 142 and the desalting chamber 141 can be greatly reduced. FIG. 5 is a diagram showing pressure states of water to be treated and treated water in the demineralization chamber and the concentration chamber of the electric deionization apparatus during the heat sterilization treatment.
For this reason, the deformation | transformation etc. of an ion exchange membrane which are easy to generate | occur | produce especially at the time of a hot-water sterilization process are prevented, and the protrusion to the concentration chamber 142 side of this ion exchange membrane and the obstruction | occlusion of the concentration chamber 142 accompanying this are prevented.

[Pure water production method]
Next, based on FIGS. 6-9, the whole flow is demonstrated about the pure water manufacturing method by the manufacturing apparatus 1 of this invention.
In the present embodiment, a method of performing a sterilization process by passing hot water through each apparatus in the manufacturing apparatus 1 after performing a normal pure water manufacturing process will be described as an example. This hot water sterilization process includes a temperature raising process, a temperature equalizing process, and a temperature lowering process. Below, the manufacturing method of the pure water by the manufacturing apparatus 1 is demonstrated.

Based on FIG. 6, the flow of a pure water manufacturing process is demonstrated.
First, pretreated water 10 treated by a pretreatment device (not shown) is supplied into the raw water tank 12 with the opening / closing valve B1 opened. Next, the on-off valve B6, the switching valves B4, B5, B8, B11 are closed, the on-off valves B2, B3, B7, B10, B12, and the switching valve B9 are opened, and the raw water in the raw water tank 12 is 20-30 ° C. Then, the pump P1 is driven and supplied to the steam heater 16 whose temperature is set to, and then this raw water is supplied to the reverse osmosis membrane device 13 by driving the pump P2 and desalted by the reverse osmosis membrane 131.
At this time, the concentrated water obtained by the reverse osmosis membrane device 13 is discharged out of the system through the concentrated water discharge valve B3.

The treated water of the reverse osmosis membrane device 13 is supplied to the electric deionization device 14 from the pipe L1-2. The treated water that has flowed into the desalting chamber 141 from the pipe L1-2 moves in the desalting chamber 141 to the treated water tank 15 side.
The treated water that has been deionized in the desalting chamber 141 is supplied to the treated water tank 15 through the supply pipe L2 via the opening / closing valve B2 that is the first pressure regulating valve. The first pressure regulating valve B2 can adjust the pressure at the outlet (exhaust port) of the desalting chamber 141 depending on the degree of opening thereof, and the desalting chamber at the time of pure water production processing can be adjusted by the pressure regulating valve B2. The pressure difference between the 141 outlet (discharge port) and the concentrating chamber 142 inlet (supply port) can be adjusted as appropriate.

On the other hand, as described in detail in FIG. 3A, the water to be treated that flows from the pipe L1-2 to the branch pipe L11 side flows from Q1 to the pipe L7 via the valve B10, and is processed in the concentration chamber 142. It flows into the concentrating chamber 142 from the water tank 15 side entrance.
In the present embodiment, the opening degree of the on-off valve B10 is determined by the treatment water tank 15 side inlet / outlet of the desalting chamber 141 and the concentrating chamber 142, that is, the outlet (exhaust port) of the desalting chamber 141 and the inlet (supply port) of the concentrating chamber 142. The supply water pressure to the concentrating chamber 142 is adjusted so that the pressure difference between the two is 50 kPa or more, and the opening degree is always fixed. During the pure water production process, the water to be supplied to the concentrating chamber 142 does not pass through the pressure adjustment valve B11, so that the water to be treated from the pipe L7 is supplied to the concentrating chamber 142 in a steady state. The treated water in the concentration chamber 142 moves to the raw water tank 12 side in the concentration chamber 142.
The concentrated water whose ion concentration has increased in the concentration chamber 142 is discharged from the raw water tank side inlet / outlet and the electrode chamber 143 outlet of the concentration chamber 142.
The concentrated water discharged from the concentration chamber 142 is discharged to the reflux pipe L10 side through the opening / closing valve B12 through the pipe L6 and the discharge pipe L13. Further, the electrode water from the electrode chamber 143 is also discharged by the pipe L9 to the reflux pipe L10 via the opening / closing valve B7. Concentrated water and electrode water flowing into the reflux pipe L10 are discharged out of the system via the switching valve B9 through the branch pipe L10-2.

As described above, in this embodiment, the supply water pressure to the concentrating chamber 142 is set by the opening / closing valve B10 having a fixed opening, and the first pressure regulating valve (opening / closing valve) B2 is used to The treated water pressure is adjusted. Thereby, the pressure difference between the desalting chamber 141 outlet and the concentration chamber 142 supply port is 50 kPa or more. Therefore, in the desalting chamber 141, treated water with low electrical conductivity and good water quality can be obtained.
In the desalting chamber 141, in order to obtain treated water with low conductivity and better water quality, the pressure difference between the desalting chamber 141 outlet and the concentration chamber 142 supply port is preferably 100 kPa or more.

Next, based on FIG. 7, the flow of the temperature raising process in the hot water sterilization process will be described.
The on-off valves B1, B2, B10, B12 and the switching valve B9 are closed, the on-off valve B6 and the switching valves B5, B8, B11 are opened, and the open / closed states of the other valves remain the same as in the pure water production process. Then, the pump P1 is driven. Thereby, the raw water in the raw water tank 12 is supplied to the steam heater 16 set to a heating temperature of 60 to 90 ° C., and the raw water is heated. Next, the heated raw water is supplied from the steam heater 16 to the reverse osmosis membrane device 13 by driving the pump P2.
In this embodiment, the reverse osmosis membrane 131 provided in the reverse osmosis membrane device 13 is a reverse osmosis membrane that performs a desalination treatment with a desalination rate of 90% or more when the water temperature of the water to be treated is 60 ° C. or higher. The desalting process is performed by the reverse osmosis membrane 131.
The concentrated water discharged from the reverse osmosis membrane device 13 is discharged out of the system through the concentrated water discharge valve B3.

The permeated water that has passed through the reverse osmosis membrane device 13 in the hot water state by the steam heater 16 has been desalted as described above, and thus is directly supplied to the electric deionization device 14.
As described in detail in FIG. 3B, the water to be treated supplied from the pipe L1-2 to the desalting chamber 141 moves to the treated water tank 15 side in the desalting chamber 141.
The treated water discharged from the desalting chamber 141 is returned to the raw water tank 12 through the return pipe L5 via the switching valve B5 that is the second pressure adjusting valve. The second pressure regulating valve B5 can adjust the pressure of the discharged water from the desalting chamber 141 according to the opening thereof, and the outlet of the desalting chamber 141 during the temperature raising process (during hot water sterilization). The pressure difference between the (discharge port) and the concentration chamber 142 outlet (discharge port) can be adjusted.

On the other hand, the water to be treated which has flowed into the branch pipes L11 and L12 from the pipe L1-2 flows into the pipe L6 via the switching valve B11 which is the third pressure regulating valve, and is concentrated from the raw water tank 12 side of the concentrating chamber 142. It is supplied into the chamber 142.
The third pressure adjusting valve B11 can adjust the pressure of the water supplied to the concentrating chamber 142 according to its opening. Thus, in addition to the second pressure adjustment valve B5 described above, the pressure adjustment valve B11 also allows the desalination chamber 141 outlet (discharge port) and the concentration chamber 142 during the temperature raising process (during hot water sterilization). The pressure difference from the outlet (discharge port) can be adjusted.
The treated water in the concentration chamber 142 moves in the concentration chamber 142 to the treated water tank 15 side.
The concentrated water discharged from the treatment water tank 15 side of the concentration chamber 142 and the treated water discharged from the electrode chamber 143 are discharged to the reflux pipe L10 side via the open / close valves B6 and B7 by the pipes L8 and L9, respectively. Thereafter, the water is returned to the raw water tank 12 through the switching valve B8 by the branch pipe L10-1.

As described above, in the present embodiment, the treated water pressure from the desalting chamber 141 is adjusted by the second pressure adjusting valve B5, and the supply water pressure to the concentrating chamber 142 is adjusted by the third pressure adjusting valve B11. Is done. Thereby, the pressure difference between the desalting chamber 141 outlet (discharge port) and the concentration chamber 142 outlet (discharge port) is set to 20 kPa or less.
Thus, during the hot water sterilization process, by reducing the pressure difference between the concentrating chamber 142 and the desalting chamber 141, deformation of the ion exchange membrane is prevented, and the ion exchange membrane toward the concentrating chamber 142 side is prevented. The overhang and the blockage of the concentrating chamber 142 accompanying this are prevented.
In this state, the raw water in the raw water tank 12 is circulated until the temperature in the system rises to 60 to 90 ° C. That is, since the water in the raw water tank 12 is circulated to raise the temperature without supplying new water to the raw water tank 12, the purification of the circulating water proceeds with the temperature rise in the system.

Next, based on FIG. 8, the flow of the soaking | uniform-heating process in a hot-water sterilization process is demonstrated.
The open / close valve B3 is closed, the switching valve B4 is opened, and the open / close state of the other valves is left in the state of the temperature raising step, and the raw water in the raw water tank 12 is changed to 60 to The raw water is supplied from the steam heater 16 to the reverse osmosis membrane device 13 while being supplied to the steam heater 16 set to 90 ° C. and the water temperature of the raw water is maintained at 60 to 90 ° C.
In the reverse osmosis membrane device 13, the raw water passed in the hot water state is desalted by the reverse osmosis membrane 131 to obtain concentrated water, but the circulating water in the system in the soaking step is already in the temperature raising step. Since it has been desalted, this concentrated water is not discharged out of the system, but is returned to the raw water tank 12 through the return pipe L4 via the switching valve B4.
In addition, you may make it discharge | emit a part of concentrated water of the reverse osmosis membrane apparatus 13 out of the system as needed.

The permeated water that has passed through the reverse osmosis membrane device 13 in the hot water state is directly supplied to the electric deionization device 14 in the same manner as in the temperature raising step.
That is, the water to be treated in the desalting chamber 141 is supplied from the raw water tank 12 side through the pipe L1-2, and moves in the desalting chamber 141 to the treated water tank 15 side. The treated water discharged from the desalting chamber 141 is returned to the raw water tank 12 through a switching valve B5 that is a second pressure regulating valve.

On the other hand, the water to be treated in the concentrating chamber 142 is supplied from the raw water tank 12 side by the pipe L6 via the switching valve B11 which is a third pressure regulating valve, and moves in the concentrating chamber 142 to the treated water tank 15 side. .
The treated water discharged from the treated water tank 15 side of the concentrating chamber 142 and the electrode chamber 143 is discharged to the reflux pipe L10 side through the open / close valves B6 and B7 through the pipes L8 and L9, respectively, and then the branch pipe L10-1 Thus, the water is returned to the raw water tank 12 via the switching valve B8.
In addition, the opening degree of the second pressure adjustment valve B5 and the third pressure adjustment valve B11 in the temperature equalization process is the same as that in the temperature increase process, and the outlet of the desalting chamber 141 (discharge port) The pressure difference with the outlet (exhaust port) of the concentration chamber 142 is 20 kPa or less.
Thereby, the inside of the electric deionization apparatus 14 can be subjected to hot water sterilization without causing deformation of the concentration chamber 142 due to deformation of the ion exchange membrane.
In addition, by circulating all the water in the production apparatus 1 including the concentrated water obtained by the reverse osmosis membrane apparatus 13, hot water sterilization can be performed efficiently without losing heat in the system. In this state, the raw water in the raw water tank 12 is circulated until each device in the system is sufficiently sterilized. The number of circulations is not particularly limited, but is usually several to several tens of times.

Next, based on FIG. 9, the flow of the temperature lowering process in the hot water sterilization process will be described.
First, the switching valves B4, B8 are closed, the valves B1, B3, B9 are opened, and the open / close state of the other valves is left in the above-described soaking process, and the normal temperature that has been subjected to the adsorption treatment by the activated carbon adsorption device 11 The raw water is supplied into the raw water tank 12.
In addition, the raw water in the raw water tank 12 is supplied to the steam heater 16 whose heating operation has been stopped. Next, this raw water is supplied to the reverse osmosis membrane device 13 in the same manner as in the temperature-uniforming step. The raw water supplied to the reverse osmosis membrane device 13 is desalted by the reverse osmosis membrane 131, and the concentrated water obtained by the reverse osmosis membrane device 13 is discharged out of the system through the concentrated water discharge valve B3.

The permeated water that has passed through the reverse osmosis membrane device 13 is directly supplied to the electric deionization device 14 in the same manner as in the temperature raising step and the soaking step.
That is, the water to be treated in the desalting chamber 141 is supplied from the raw water tank 12 side through the pipe L1-2, and moves in the desalting chamber 141 to the treated water tank 15 side.
On the other hand, the water to be treated in the concentrating chamber 142 is supplied from the raw water tank 12 side through the pipe L6, and moves in the concentrating chamber 142 to the treated water tank 15 side.

The treated water discharged from the desalting chamber 141 is returned to the raw water tank 12 through the switching valve B5, which is a third pressure regulating valve, but the concentrated water of the reverse osmosis membrane device 13 and the electric deionization device 14 are used. The concentrated water and electrode water are discharged out of the system from the reflux pipe L3, the reflux pipe L10, and the branch pipe L10-2, respectively.
In this state, the raw water in the raw water tank 12 is circulated until the temperature in the system drops to 20-30 ° C.
In addition, the opening degree of the second pressure regulating valve B5 and the third pressure regulating valve B11 in the temperature lowering process is performed as the same opening degree as in the temperature equalizing process, and the outlet of the desalting chamber 141 (discharge port) and the concentration are performed. The pressure difference with the chamber 142 outlet (discharge port) is 20 kPa or less.

  As described above, in the pure water production method of the present invention, in the pure water production process, the water to be treated in the concentration chamber 142 is passed in the direction opposite to the water flow direction of the desalting chamber 141. The increase in the ion concentration in the gas can be prevented, the clogging of the concentration chamber 142 can be prevented, and the shortening of the life of the electric deionizer 14 can be prevented. Further, during the hot water sterilization treatment, the pressure difference between the desalting chamber 141 and the concentrating chamber 142 is changed by switching the water passing direction of the concentrating chamber 142 and passing the water in the same direction as the water passing direction of the desalting chamber 141. Reduces the flow rate of concentrated water, that is, reduces the processing efficiency and shortens the life of the deionizer because it can reduce the deformation of the ion exchange membrane during hot water sterilization and prevent the concentrating chamber from being blocked. be able to.

  In this embodiment, by using the reverse osmosis membrane device 13 including the reverse osmosis membrane 131 described above, pure water is produced by passing raw water at normal temperature through the reverse osmosis membrane 131 in advance, and then this pure water. Thus, the hot water sterilization step can be performed without replacing the raw water in the raw water tank 12 and supplying the raw water to the electric deionizer 14. That is, in the hot water sterilization process, the permeated water that has been passed through the reverse osmosis membrane 131 in the hot water state can be directly supplied to the electric deionization device 14 to be sterilized with hot water, greatly reducing the time required for the sterilization process. This shortens the processing water and energy required for sterilization.

  As mentioned above, although the pure water manufacturing method of this invention was demonstrated, the implementation order etc. can be changed suitably in the range which does not impair the effect of this invention.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Raw water (Atsugi City water) was treated using the pure water production apparatus 1 shown in FIG.
In addition, about the apparatus structure, the front stage part (reverse osmosis membrane apparatus 3) of Nomurax EP-10 (Nomura Micro Science Co., Ltd. make, brand name) was used for the front stage apparatus structure of the pure water manufacturing apparatus 1. FIG.

As the activated carbon adsorption device 11 in FIG. 1, AC cylinder NCC-200AC (trade name, manufactured by Nomura Micro Science Co., Ltd.) is used, and Kuraray Coal KW (trade name, manufactured by Kuraray Chemical Co., Ltd.) is used as the activated carbon to be attached thereto. Was used.
The reverse osmosis membrane device 13 is a reverse osmosis membrane 131 using a reverse osmosis membrane device using Duratherm RO 4040 HF (manufactured by GE), and the electric deionization device 14 is MK-3 MiniHT (GE Corporation). Product name).

Example 1
[Pure water production process]
First, the open / closed state of each valve B1 to B12 of the pure water production apparatus 1 is set to the state described in FIG. 6, and the raw water stored in the raw water tank 12 is converted into a membrane treatment device, a reverse osmosis membrane device 13, and a hardness removal device. Water was passed in order. The conductivity of the treated water of the hardness removing device was 20 μS / cm or less. Next, this treated water was supplied as supply water for the electric deionizer 14. At this time, the amount of water supplied to the desalting chamber 141 is 1.7 L / min. / Cell, and the amount of water supplied to the concentration chamber 142 is 0.6 L / min. Water was passed as / cell, and a current of 4.5 A was applied to the electric deionizer 14. Further, the water flow direction to the concentrating chamber 142 is the direction shown in the pure water production step 1 in Table 1, and the pressure of the desalting chamber 141 inlets and outlets A and B (see FIG. 3A) and the concentrating chamber 142 inlet and outlet C , D (see FIG. 3A), the pressure shown in the pure water production step 1 in Table 1 was used.
In this state, the raw water in the raw water tank 12 was passed for 900 minutes to perform pure water production processing.

[Hot water sterilization process]
Next, the production of pure water is temporarily stopped, and the open / closed state of each of the valves B1 to B12 is set to the state described in FIG. 7, and the raw water in the raw water tank 12 is passed through the membrane treatment device. It supplied to the steam heater 16 set so that it might heat at degreeC, and water-flowed, heating. Next, the heated raw water (water temperature 20 to 85 ° C.) was passed through the reverse osmosis membrane device 13 and the hardness component removing device in this order. The conductivity of the treated water of the hardness removing device was 45 μS / cm or less. Next, this treated water was passed through the electric deionizer 14. In this state, the raw water in the raw water tank 12 was circulated for 60 minutes until the temperature in the system reached 85 ° C.
Thereafter, with the temperature of the steam heater 16 set to 85 ° C., the open / closed state of the valves B 1 to B 12 is set to the state shown in FIG. 8, and hot water with a water temperature of 85 ° C. is circulated in the pure water production apparatus 1 for 30 minutes. Then, hot water sterilization treatment was performed. At this time, the temperature of the supply water to the electric deionization device 14 was 85 ° C., and the temperature of the discharged water discharged from the electric deionization device 14 was 84 ° C.
Next, after stopping the heating operation of the steam heater 16, the open / close state of the valves B <b> 1 to B <b> 12 is changed to the state shown in FIG. 9, the pretreated water 10 is supplied to the raw water tank 12, and the hot water in the raw water tank 12 is Mixed. At the same time, this mixed water is passed in the order of the membrane treatment device, the steam heater 16, the reverse osmosis membrane device 13, the hardness component removal device, and the electric deionization device 14 in the same manner as described above, and the raw water becomes 25-30 ° C. Up to 90 minutes in the pure water production apparatus 1
At this time, the flow direction of the water to be treated to the concentrating chamber 142, the desalting chamber 141 inlets and outlets A and B (see FIG. 3B), and the concentrating chamber 142 inlets and outlets C and D (FIG. 3B). Reference :) The pressure was set to the direction and pressure value shown in each hot water sterilization step (temperature raising step, temperature equalizing step, temperature lowering step) in Table 1, respectively.
Moreover, the flow rate of the demineralization chamber 141 of the electric deionization apparatus 14 in the hot water sterilization process (heating process, soaking process, cooling process) is 1.0 L / min. / Cell.

In the pure water production apparatus 1, the pure water production treatment step 1, the confirmation step 1, the hot water sterilization step, and the confirmation step 2 were repeated five times in this order under the above-described conditions.
Of these, in the confirmation steps 1 and 2, the water flow direction to the concentration chamber 142 is the direction shown in “confirmation step 1” and “confirmation step 2” in Table 1, and the desalination chambers 141 entrances A and B (FIG. 3 (a ) Reference) Pressure and concentration chamber 142 inlet / outlet C, D (see FIG. 3A) The pressure is discharged from the desalting chamber 141 as the pressure shown in “Confirmation Step 1” and “Confirmation Step 2” in Table 1. The demineralized water flow rate and the concentrated water flow rate discharged from the concentration chamber 142 were measured. Confirmation step 1 and confirmation step 2 were each performed for about 30 minutes.
Moreover, after the confirmation process 2, the water flow direction of the concentration chamber 142 is set to the direction shown in “Pure water production process 1” in Table 1, and the pressure and the desalination chamber 141 entrances A and B (see FIG. 3A) and Concentration chamber 142 inlet / outlet C, D (see FIG. 3 (a)) The pressure shown in “Pure water production step 1” in Table 1 is the dewatering chamber 141 outlet water when the process moves to pure water production step 1. The electrical conductivity (μS / cm) of was measured.
Table 3 shows the flow rate change rate (%) of the desalted water and concentrated water and the electrical conductivity (μS / cm) of the desalting chamber 141 outlet water at each time (1 time, 3 times, and 5 times).
Note that the rate of change in flow rate (%) indicates the demineralization chamber 141 and the concentration chamber 142 when the pure water production process is performed using the electric deionization apparatus 14 before the hot water sterilization process (the number of times of hot water sterilization is 0). The ratio of the flow rate of the demineralized water and the concentrated water in the confirmation step 2 (after the hot water sterilization treatment) is expressed as a percentage (%) based on the flow rate of the demineralized water and the concentrated water discharged from the water.

(Comparative Example 1)
Using the pure water production apparatus 2 provided with the electric deionization apparatus 14 having the configuration shown in FIG. 10, the direction of water flow to the concentration chamber 142 is the direction shown in the pure water production process 1 in Table 2, and the demineralization chamber 141. Pure water production under the same conditions as in the pure water production process of Example 1, except that the inlet / outlet A, B pressure and the concentration chamber 142 inlet / outlet C, D pressure were set to the values shown in the pure water production process 1 of Table 2. Processed.
Thereafter, in this pure water production apparatus 2, the direction of water flow to the concentration chamber 142 is set to the direction shown in each hot water sterilization step (temperature raising step, temperature equalizing step, temperature lowering step) in Table 2, and the entrance and exit of the desalting chamber 141 Except that the A and B pressures and the concentration chamber 142 inlet and outlet C and D pressures were set to the pressure values shown in the respective hot water sterilization steps (temperature raising step, temperature equalizing step, temperature lowering step) in Table 2, the same as in Example 1. The hot water sterilization process was performed on condition of this.

In the pure water production apparatus 2, the pure water production treatment step 1, the confirmation step 1, the hot water sterilization step, and the confirmation step 2 were repeated twice in this order under the above-described conditions.
Among these, in the confirmation steps 1 and 2, the water flow direction to the concentration chamber 142 is the direction shown in “confirmation step 1” and “confirmation step 2” in Table 1, and the desalination chambers 141 entrances A and B (FIG. 3 ( Refer to a).) Pressure and concentration chamber 142 inlet / outlet C, D (see FIG. 3A) The pressures shown in “Confirmation step 1” and “Confirmation step 2” in Table 1 The flow of the demineralized water discharged and the flow of the concentrated water discharged from the concentration chamber 142 were measured. Confirmation step 1 and confirmation step 2 were each performed for about 30 minutes.
Next, after the confirmation step 2, the water flow direction of the concentration chamber 142 is set to the direction shown in “Pure water production step 1” in Table 1, and the pressure and the desalination chamber 141 entrances A and B (see FIG. 3A) and Concentration chamber 142 inlet / outlet C, D (see FIG. 3 (a)) The pressure shown in “Pure water production step 1” in Table 1 is the dewatering chamber 141 outlet water when the process moves to pure water production step 1. The electrical conductivity (μS / cm) of was measured.
Table 3 shows the flow rate change rate (%) of the desalted water and the concentrated water and the electrical conductivity (μS / cm) of the desalted chamber 141 outlet water at each time (once and twice).

  From the above results, by switching the flow direction of the concentration chamber between the pure water production process and the hot water sterilization process as shown in Table 1, even during the pure water production process after the hot water sterilization process, It has been found that the flow rate ratio between the desalting chamber and the concentrating chamber is small and can be used without reducing the processing capacity of the electric deionization apparatus 141. Moreover, it turned out that the fall of the treated water quality obtained by a pure water manufacturing process is not seen.

DESCRIPTION OF SYMBOLS 1 Pure water production apparatus 12 Raw water tank 13 Reverse osmosis membrane apparatus 14 Electric deionization apparatus 141 Desalination chamber 142 Concentration chamber 143 Electrode chamber 15 Treated water tank 16 Steam heaters B1, B2, B6, B7, B10, B12 On-off valve B3 Concentrated water discharge valve
B4, B5, B8, B9, B11 Switching valve L1 to L2 Supply pipe L3 Concentrated water discharge pipe L4 to L5 Reflux pipe L6 to L9 Pipe L10 Reflux pipe L10-1 to L10-2 Branch pipe L11 to L12 Branch pipe L13 Discharge pipe

Claims (8)

A pure water production method in which a deionized water production process in which deionization is performed by an electric deionization apparatus and a hot water sterilization process in which hot water is supplied to the electric deionization apparatus and sterilized are alternately repeated. ,
The flow of water to be treated in the concentrating chamber of the electric deionizer during the pure water production process is a countercurrent direction with respect to the flow of water to be treated in the demineralization chamber, and the hot water sterilization At the time of treatment, the flow direction of the water to be treated in the concentration chamber of the electric deionization apparatus is set as a parallel flow direction to the flow direction of the water to be treated in the demineralization chamber.
The pure water manufacturing method characterized by the above-mentioned. The pressure difference between the demineralization chamber outlet and the concentration chamber inlet of the electric deionizer during the pure water production process is 50 kPa or more, and the demineralization chamber outlet and the concentration chamber outlet during the hot water sterilization process. The method for producing pure water according to claim 1, wherein the pressure difference between them is 20 kPa or less. The method for producing pure water according to claim 1 or 2, wherein the hot water used in the hot water sterilization treatment is hot water having a water temperature of 60 ° C or higher. 4. The reverse osmosis membrane device having a conductivity of permeated water of the reverse osmosis membrane device of 45 μS / cm or less at a water temperature of 60 ° C. or higher of the water to be treated of the reverse osmosis membrane device. The pure water manufacturing method of any one of these. In each process of temperature increase, temperature equalization and temperature decrease to sterilize the system with hot water at the start of production of pure water,
(A) In the temperature raising step, the water to be treated supplied from the raw water tank to the reverse osmosis membrane device is heated to a temperature of 60 ° C. or higher by the heating means, and the supply of the raw water to the raw water tank is stopped. The concentrated water of the reverse osmosis membrane device is discharged, and the demineralized water, concentrated water, and electrode water of the electric deionizer are recirculated to the raw water tank.
(B) In the soaking step, while continuing the heating, the inflow of the raw water into the raw water tank is stopped, the concentrated water of the reverse osmosis membrane device, the concentrated water of the electric deionizer, electrode water, and demineralized water To the raw water tank,
(C) In the temperature lowering step, the heating is stopped, the raw water is supplied to the raw water tank, the concentrated water of the reverse osmosis membrane device, the concentrated water of the electric deionization device, and the electrode water are discharged, Demineralized water from the deionizer is returned to the treatment tank.
The pure water manufacturing method of any one of Claims 1 thru | or 4 characterized by the above-mentioned. An electric deionization apparatus comprising a plurality of anion exchange membranes and cation exchange membranes arranged between a cathode and an anode to form a demineralization chamber and a concentration chamber. An apparatus for producing pure water that alternately performs sterilization treatment,
During the pure water production process, the electric deionization apparatus introduces water to be treated into the concentration chamber from the side near the demineralized water outlet of the demineralization chamber, and the demineralization chamber in the concentration chamber. Concentrated water is allowed to flow out from the side close to the treated water inlet, and during the hot water sterilization treatment, treated water is introduced into the concentration chamber from the side near the treated water inlet of the desalting chamber, An apparatus for producing pure water, comprising control means for allowing concentrated water to flow out from a side of a desalting chamber close to a desalted water outlet.   The pure water production apparatus according to claim 6, wherein the electric deionizer includes a pressure adjusting unit that adjusts a pressure difference between the demineralization chamber and the concentration chamber. The pressure adjusting means is a pressure adjusting valve provided in a treated water supply channel to the concentrating chamber and a pressure regulating valve provided in a treated water channel of the desalting chamber during the hot water sterilization treatment.
The pure water manufacturing apparatus according to claim 6 or 7, wherein

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