JP2014124482A - Method of sterilizing pure water production apparatus for pharmaceuticals and pure water production apparatus for pharmaceuticals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of sterilizing a pure water production apparatus for pharmaceuticals capable of improving the hot water sterilizing efficiency and of ultimately inhibiting effects exerted onto an electric deionizer at the time of a hot water sterilizing treatment; and a pure water production apparatus for pharmaceuticals.SOLUTION: A provided method of sterilizing a pure water production apparatus is a method of sterilizing a pure water production apparatus furnished not only with a pump, a heat exchanger, a reverse osmotic membrane device, and an electric deionizer in proper order along a treatment line connecting a raw water tank and a pure water tank or use point but also with circulatory lines connecting, to the raw water tank via ON-OFF valves, the respective outlet-side pipelines of the reverse osmotic membrane device and the electric deionizer wherein hot water is circulated through the treatment line and the circulatory lines, wherein concentrated water within the reverse osmotic membrane device is subsequently discharged out of the system while non-heated raw water is being fed into the raw water tank, and wherein the non-heated raw water is circulated through the treatment line and the circulatory lines.

Description

  The present invention relates to a method for sterilizing a pure water production apparatus for pharmaceuticals and a pure water production apparatus for pharmaceuticals, and more particularly, to a pure water production apparatus for pharmaceuticals comprising a reverse osmosis membrane device and an electrodeionization device. The present invention relates to a sterilization method for sterilization by using water and an apparatus for producing pure water for pharmaceuticals.

  Conventionally, as a pure water manufacturing apparatus for pharmaceuticals, a pure water manufacturing apparatus in which a reverse osmosis membrane apparatus and an electrodeionization apparatus are sequentially arranged in a processing line between a raw water tank for storing raw water and a pure water tank or a use point It has been known. Pure water for pharmaceuticals is produced by removing ionic components, fine particles, organic substances, and the like from raw water such as city water using such a pure water production apparatus.

  When producing pure water for pharmaceuticals using this pure water production device, the Japanese Pharmacopoeia requires that sterilization treatment that periodically reduces viable bacteria in the system is performed due to the nature of pharmaceutical use. Yes.

  The sterilization process in the system is performed, for example, by passing hot water of 65 ° C. or higher from a raw water tank through a processing line including a reverse osmosis membrane device and an electrodeionization device for a predetermined time. In order to perform a sufficient sterilization treatment, it is desired that the sterilization treatment is precisely controlled so that the temperature of the hot water in the system is stably maintained at the above-described temperature or more for a predetermined time or more.

  Moreover, in the case of sterilization treatment, in order to avoid damage to the electrodeionization apparatus due to high-temperature pressure, it is desirable that hot water be passed at a pressure lower than that during normal operation. However, when the water flow pressure of the reverse osmosis membrane device is lowered, the quality of the permeated water of the reverse osmosis membrane device deteriorates, and water of water quality that does not meet the water flow standard of the electrodeionization device is supplied to the electrodeionization device. There is a risk of being.

  For this reason, the processing line including the reverse osmosis membrane device is sterilized with hot water up to just before the electrodeionization device, and then processed at room temperature by the reverse osmosis membrane device after the hot water sterilization. In addition, a method in which high quality water is heated with a heat exchanger and passed through an electrodeionization apparatus to sterilize is used (for example, see Patent Document 1).

  As another method, a method is also proposed in which a sub-tank for storing soft water treated by the pure water production apparatus is arranged, and a pure water production apparatus in which the circulation system is configured to replace the raw water tank with the soft water in the sub-tank is also proposed. (For example, refer to Patent Document 2).

  According to this method, during the sterilization treatment, the soft water treated with the pure water production apparatus is heated and circulated, so that the permeated water of the reverse osmosis membrane apparatus is directly used as an electrodeionization apparatus even at a lower pressure than during normal operation. It can be supplied and sterilized.

Japanese Patent No. 3570304 Japanese Patent No. 4617696

  Here, in the method of sterilizing the reverse osmosis membrane device and the electrodeionization device, the sterilization process takes time, and a large amount of steam for heating increases the sterilization running cost. There is a problem of end.

  On the other hand, in the method of passing and sterilizing the reverse osmosis membrane device and the electrodeionization device at once, for example, while adjusting the supply water pressure to the reverse osmosis membrane device so as to prevent damage to the electrodeionization device, There is a problem that the sterilization efficiency decreases. Furthermore, since a device for producing or storing soft water for sterilization is required, there is a problem that the number of staying portions where viable bacteria are likely to grow increases and sterilization treatment takes time.

  In addition, for cooling the system after passing hot water, a method of cooling by circulating soft water, a method of naturally cooling, and the like have been proposed. However, the former method has a problem of increasing the number of staying portions, and the latter method has a problem that the cooling time becomes long, and the time for stopping the voltage of the electrodeionization device becomes long, and the hardness of the electrodeionization device is increased. There was a problem that the amount of accumulation increased.

  Moreover, in hot water sterilization, the higher the hot water temperature, the shorter the sterilization time may be. On the other hand, the higher the temperature, the more easily the members constituting the pure water production apparatus are damaged. By shortening and suppressing damage to each member due to hot water sterilization, and sufficiently reducing the number of viable bacteria in the system after hot water sterilization, it will be possible to produce pure water stably for a long time It is also desired.

The present invention has been made to solve the above-described problems, and the reverse osmosis membrane device and the electrodeionization device can be subjected to a hot water sterilization treatment using raw water at the same time, and a hot water sterilization time, In particular, an object of the present invention is to provide a sterilization method for a pharmaceutical production apparatus and a pure water production apparatus capable of shortening the temperature drop time and improving the sterilization efficiency.
Furthermore, it aims at providing the sterilization method of the pure water manufacturing apparatus for pharmaceuticals which can suppress the influence on an electrodeionization apparatus as much as possible, and can extend the lifetime of a pure water manufacturing apparatus, and the pure water manufacturing apparatus for pharmaceuticals To do.

  At the time of the hot water sterilization treatment, not only the hot water is circulated but also the temperature of the circulating water is changed (temperature increase and temperature decrease), so various phenomena can occur in the pure water production apparatus. For example, not only does the permeated water pressure of the reverse osmosis membrane device increase due to a decrease in the viscosity of water due to temperature rise, but if hot water is passed during the hot water sterilization treatment, each member constituting the pure water production device expands. It is also possible that local deformation occurs. And the flow volume of circulating water may fluctuate from the preset value by the fall of the viscosity of this water, or a deformation | transformation of a member. The fluctuation in the flow rate of the circulating water leads to fluctuations in the temperature raising rate and the temperature lowering rate, which may hinder sufficient sterilization treatment or cause each device to deteriorate.

  When water quality deteriorates or each device deteriorates in a pharmaceutical pure water production apparatus, it is necessary to stop the operation of the pure water production apparatus and replace components. Even during the production of pure water, it is necessary to periodically inspect the apparatus and perform water quality inspection and maintain the water treatment apparatus. Therefore, in order to reduce the frequency of such maintenance and inspection management and to produce pure water stably for a long period of time, the following two points must be first sterilized in the hot water sterilization treatment: Secondly, it is important to suppress deterioration of each device as much as possible.

  By the way, the ion exchange membrane of the electrodeionization device when hot water is passed for a long time until the quality of the treated water decreases with the reverse osmosis membrane device and the electrodeionization device directly connected is irreversible due to deterioration. Has been discovered.

  Therefore, the present inventors based on the above two points, a member for cooling the circulating water by supplying the raw water into the pure water production system in the temperature reduction process of the sterilization process and cooling the temperature, The present inventors have found that the use of the apparatus and the cooling water is omitted, and the temperature lowering time is shortened by controlling the amount of water retained in the pure water producing apparatus system when the temperature is lowered.

  The present invention has been made on the basis of such knowledge, and the sterilization method for a pharmaceutical pure water production apparatus according to the present invention includes a pump, a heat pump along a treatment line connecting a raw water tank and a pure water tank or a use point. A circulation line comprising an exchanger, a reverse osmosis membrane device, and an electrodeionization device in this order, and connecting each outlet side pipe of the reverse osmosis membrane device and the electrodeionization device to the raw water tank via an open / close valve. A method for sterilizing a pure water production apparatus comprising: after circulating hot water through the treatment line and the circulation line, supplying concentrated water from the reverse osmosis membrane device while supplying unheated raw water to the raw water tank The unheated raw water is discharged out of the system and circulated through the treatment line and the circulation line.

  In the sterilization method of the present invention, it is preferable that the supply flow rate of the unheated raw water and the discharge flow rate of the concentrated water of the reverse osmosis membrane device are the same.

  In the sterilization method of the present invention, an opening variable valve is interposed in the concentrated water discharge pipe of the reverse osmosis membrane device to supply the non-heated raw water and adjust the opening of the variable opening valve. It is preferable to adjust the concentrated water discharge flow rate of the reverse osmosis membrane device.

  Still further, a pressure sensor is disposed in the permeate pipe of the reverse osmosis membrane device of the treatment line, and the pressure is changed while the pump is used as a rotation speed variable pump, and hot water is circulated through the treatment line and the circulation line. It is preferable to control the rotation speed of the variable speed pump so that the output of the sensor becomes constant. In this case, since the inside of the pure water production apparatus can be made steady and sterilized with hot water, the life of the pure water production apparatus can be extended.

  Furthermore, the supply of the raw water to the raw water tank is stopped, the raw water stored in the raw water tank is circulated to the circulation line, and at least a part of the raw water is discharged out of the system, while the heat exchange of the raw water is performed. It is preferable to produce the hot water by heating with a vessel. Thus, the temperature rise efficiency can be improved by raising the temperature of the circulating water. Furthermore, since the raw water can be circulated and sterilized, the sterilization can be performed at low cost, and a pure water apparatus that has as little a stagnant portion as possible can be configured.

  Moreover, it is preferable that the temperature of the hot water is 60 ° C. or higher.

  The pure water production apparatus for pharmaceuticals of the present invention comprises a pump, a reverse osmosis membrane device, and an electrodeionization device in this order along a processing line connecting the raw water tank and the pure water tank or use point, and the reverse osmosis membrane device Concentrated water piping, concentrated water piping of electrodeionization device, electrode water piping, and treated water piping of electrodeionization device are connected to the raw water tank through open / close valves, respectively. A concentrated water discharge pipe provided by branching from a concentrated water pipe of the reverse osmosis membrane device via an opening degree variable valve, and a permeated water pipe of the reverse osmosis membrane device of the treatment line When the unheated raw water is supplied to the raw water tank to cool the inside of the pure water production system, the supply flow rate of the unheated raw water and the concentrated water of the reverse osmosis membrane device are The discharge flow rate is So that the amount, characterized by comprising a control device for controlling the opening of the pressure sensor opening variable valve interposed in the concentrated water discharge pipe by the output of.

  ADVANTAGE OF THE INVENTION According to this invention, a reverse osmosis membrane apparatus and an electrodeionization apparatus can be sterilized by carrying out water flow collectively using raw water. Furthermore, according to this invention, while reducing the apparatus and cooling water for cooling a pure water manufacturing apparatus, temperature fall (cooling) time can be shortened.

It is a schematic block diagram which shows one Embodiment of the pure water manufacturing apparatus of this invention. It is a graph which shows the change of the raw water tank exit water temperature by the sterilization method of an Example, and the permeated water quality of a reverse osmosis membrane apparatus. It is a graph which shows the change of the raw water tank exit water temperature by the sterilization method of a comparative example, and the permeated water quality of a reverse osmosis membrane apparatus.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail, referring drawings. The present invention is not limited to the following embodiments.

FIG. 1 is a schematic configuration diagram showing an embodiment of the pure water production apparatus of the present invention.
The pure water production apparatus 1 includes a raw water tank 10 that receives and stores raw water, a pump P1 that circulates the raw water stored in the raw water tank 10 to a treatment line and a circulation line, and a rear stage of the pump P1, A heat exchanger 11 for adjusting the temperature, a pump P2 for supplying the circulated water heat-exchanged in the heat exchanger 11 to the reverse osmosis membrane device 12, a reverse osmosis membrane device 12 for removing ionic components, fine particles and organic substances from the circulated water, An electrodeionization device 13 for further removing ionic components in the permeated water of the reverse osmosis membrane device 12 is provided along the line L1, which is a treatment line.

  The pure water production apparatus 1 according to the present embodiment includes a temperature measuring unit 16 in the treatment line L1 directly below the raw water tank 10.

The pure water production apparatus 1 includes a line L2 for supplying raw water to the raw water tank 10, a line L1 constituting a flow path from the raw water tank 10 to a pure water tank or a use point (not shown), and a concentration of the reverse osmosis membrane apparatus 12. A line L3 for discharging water and a line L5 for discharging concentrated water and electrode water of the electrodeionization device 13 are provided. Moreover, the line L4 branched from the line L3 and connected to the raw water tank 10, the line L6 branched from the line L5 and connected to the raw water tank 10, and the raw water branched from the subsequent stage of the electrodeionization device 13 of the line L1. Lines L7 connected to the tank 10 are provided.
In the pure water production apparatus 1, a circulation line through the raw water tank 10 is constituted by the line L1, the line L4, the line L6, and the line L7 as described above.

  A valve V1 is interposed in the vicinity of the pure water tank or use point on the line L1. Further, valves V2 to V7 are interposed in the lines L2 to L7.

  The pumps P1 and P2 are pumps with variable rotation speeds as necessary. Each valve is a variable opening valve as required. For example, at least the valve V4 is a variable opening valve.

  Moreover, the pressure sensor which measures the pressure of the circulating water supplied to the electrodeionization apparatus 13 just before the electrodeionization apparatus 13 in the permeate piping of the reverse osmosis membrane apparatus 12 of the processing line of the pure water manufacturing apparatus 1. 14 is arranged.

  The pure water production apparatus 1 includes a control device 15 that controls the number of rotations of the pump and the opening of the valve according to the supply flow rate of the raw water to the raw water tank, the permeate flow rate of the reverse osmosis membrane device 12, the concentrated water flow rate, and the like. I have. The control device 15 controls the heat medium flow rate and raw water supply flow rate supplied to the heat exchanger according to a preset temperature increase rate, temperature decrease rate, and hot water temperature in each step. Yes.

  In addition to the above-described water treatment apparatus, the pure water production apparatus 1 may be provided with a conventionally known water treatment apparatus according to the quality of raw water or the produced pure water. For example, a deaeration membrane device may be provided between the reverse osmosis membrane device 12 and the electrodeionization device 13 in order to obtain higher quality pure water for pharmaceuticals. May be equipped with an ultraviolet oxidation device.

  When pure water is produced by the pure water production apparatus 1, the valves V1 to V3 and the valve V5 are opened, and the valves V4, V6 and V7 are closed. Raw water is supplied from the line L2 to the raw water tank 10, and is sent from the raw water tank 10 to the treatment line L1 via the pump P1. The raw water is pressurized by the pumps P1 and P2 through the heat exchanger 11, impurities are removed by the reverse osmosis membrane device 12 and the electrodeionization device 13, and supplied to a pure water tank or a use point.

In the pure water manufacturing apparatus 1 of this embodiment, before manufacturing pure water, it sterilizes with the sterilization method of embodiment. After the sterilization treatment is performed and the pure water production apparatus 1 is cooled to a temperature suitable for the production of pure water, a water filling step for introducing the raw water into the raw water tank is performed, and a normal operation for producing pure water is performed.
Next, the sterilization method of this embodiment will be described.

[Draining process]
In the present embodiment, at the initial stage of the sterilization treatment, a water draining process is performed in which at least a part of the raw water stored in the raw water tank 10 is discharged out of the system.

  In the water draining process, the raw water supply is stopped in a state where the raw water is stored in the raw water tank 10, the raw water is supplied to the heat exchanger 11 by the pump P 1, and the temperature measured by the temperature measuring means 16 is changed by the heat exchanger 11. Heat to about 38-40 ° C. The heated raw water is supplied to the reverse osmosis membrane device 12 at a predetermined pressure by the pump P2, the permeated water of the reverse osmosis membrane device 12 is subsequently supplied to the electrodeionization device 13, and the treated water of the electrodeionization device 13 is supplied. Circulate to the raw water tank 10.

  At this time, the valves V1, V2, and V6 are closed, and the valves V3 to V5 and V7 are opened, so that the amount of water stored in the raw water tank 10 is about 20 to 30% of that during normal operation. A part of the concentrated water is discharged out of the system, and the rest is circulated to the raw water tank 10. The concentrated water and electrode water of the electrodeionization apparatus 13 are discharged out of the system.

  By setting the amount of water stored in the raw water tank in the above-described range in the draining process, the temperature rise time of the circulating water can be shortened. Therefore, the sterilization efficiency can be improved. Furthermore, water of a predetermined quality or higher can be circulated during hot water sterilization. Therefore, facilities for treating raw water for hot water sterilization can be reduced, and tanks for storing circulating water that has been treated with raw water and pipes and members for introducing this circulating water can be reduced. can do.

  Since the raw water is passed through the reverse osmosis membrane device in the water draining process and the water quality is improved, the load on the electrodeionization device can be reduced. In addition, in the draining process, the electrodeionization apparatus applies a voltage in order to further improve the quality of hot water circulated in the hot water sterilization process, which will be described later, and to suppress deterioration of the membrane provided in each apparatus. Also good.

[Temperature raising process and hot water sterilization process]
Following the temperature raising step, a temperature raising step is performed in which the circulating water is circulated while being heated to about 60 ° C. or higher, more preferably about 90 ° C. by the heat exchanger 11.

Specifically, the pump P2 is stopped when the temperature of the circulating water measured by the temperature measuring means 16 in the water draining process reaches 40 ° C. The valves V1, V2, V3, and V5 are closed, the valves V4, V6, and V7 are opened, the steam of the heat source is supplied to the heat exchanger 11, and the raw water in the raw water tank 10 is heated to treat the processing line L1 and the circulation line L4. , L6 and L7. And when the temperature of circulating water becomes 60 to 90 degreeC, the hot-water sterilization process circulated while keeping hot water temperature at the above-mentioned temperature is performed. In the hot water sterilization step, the amount of steam of the heat source of the heat exchanger 11 is adjusted based on the detected value of the temperature measuring means 16, and the circulating water is circulated so as to have a substantially constant temperature.
In order to reduce damage to the reverse osmosis membrane device and the electrodeionization device, the temperature raising rate in the temperature raising step is preferably about 1-2 ° C./min.

  In the present embodiment, a reverse osmosis membrane device and an electrodeionization device using heat-resistant members are used. In the hot water sterilization process, high-temperature hot water comes into contact with these members for a predetermined time. . Therefore, it is considered that the reverse osmosis membrane, the ion exchange membrane, and the ion exchange resin in the hot water sterilization process are more likely to be deformed or deteriorated due to the pressure of circulating water than normal temperature.

  Furthermore, the membrane module of the reverse osmosis membrane device is complicated and precise, and may be mechanically damaged by temperature fluctuations and pressure fluctuations at high temperatures.

Normally, in the reverse osmosis membrane device, the quality of the permeated water obtained changes with the change in the permeate flow rate, but the deterioration due to the scale formation or damage to the reverse osmosis membrane device as described above reduces the permeate flow rate. This may lead to deterioration of the permeate quality.
Furthermore, a decrease in the permeate flow rate due to aging deterioration of the reverse osmosis membrane device hinders the supply of hot water at a sufficient temperature and flow rate to each part of the pure water production device. It was necessary to check the flow rate of the circulating water and adjust the output values of the valves and pumps appropriately.

  Therefore, in the present embodiment, the pressure in the permeate water pipe (inlet water pipe of the electrodeionization device 13) of the reverse osmosis membrane device 12 is measured by the pressure sensor 14 through the temperature raising process, the hot water sterilization process, and the temperature lowering process described later. It is preferable to control the number of rotations of the pump P1 by the control device 15 so that the pressure becomes constant.

  As a result, the flow rate and temperature change in the system can be made steady, the decrease in the amount of permeated water in the reverse osmosis membrane device and the deterioration of the water quality can be suppressed, and daily maintenance and inspection management can be simplified. Moreover, it can suppress that an electrodeionization apparatus deteriorates exceeding the water flow reference | standard water quality of an electrodeionization apparatus by suppressing the deterioration of the permeation | transmission water quality of a reverse osmosis membrane apparatus.

  Furthermore, by making the permeate flow rate of the reverse osmosis membrane device constant, a decrease in the flow rate of circulating water can be suppressed, and hot water with a sufficient temperature and a sufficient flow rate can be distributed in the pure water production system. Therefore, even when the hot water sterilization treatment is repeated, the number of viable bacteria can be reduced as much as possible, and the hot water sterilization efficiency can be improved.

  The set pressure of the pressure sensor can be determined according to the breaking strength of the ion exchange membrane provided in the electrodeionization apparatus, and is set in the range of 0.03 to 0.30 MPa, for example. The pressure control of the control device is preferably performed by inverter control so as to be strictly constant within a range of ± 0.01 to 0.05 MPa with respect to a preset set pressure.

  By doing so, the state in the system in the temperature raising step and the hot water sterilization step is made steady, enabling sterilization at a higher temperature, and damage to the ion exchange resin and ion exchange membrane due to heat and pressure. Can be reduced.

  Further, on the reverse osmosis membrane surface of the reverse osmosis membrane device, when the permeate flow rate increases, the amount of impurities blocked on the membrane surface increases, and so-called concentration polarization occurs in which the impurity concentration on the membrane surface on the supply water side increases. , Contributing to the generation of scale. As described above, during hot water circulation, there is a possibility that the viscosity of the hot water will decrease and local deformation of the components of each water treatment device may occur, which may cause the permeate flow rate to change temporarily or partially. is there. Therefore, it is considered that concentration polarization partially occurs, and scale formation on the reverse osmosis membrane surface may be promoted.

  Furthermore, in this embodiment, the city water etc. containing the hardness component that causes the scale is used as raw water, and this is passed through the reverse osmosis membrane device etc. to perform sterilization treatment, so soft water or pure water is used. The amount of hardness components in the circulating water is greater than when doing this.

  Therefore, in the present embodiment, from the viewpoint of equalizing the flow velocity on the reverse osmosis membrane surface and reducing the load on the electrodeionization apparatus due to the supply of hardness components, the temperature raising step and the hot water sterilization step In the reverse osmosis membrane device, the ratio of the concentrated water flow rate / permeated water flow rate (hereinafter abbreviated as C / P) is preferably set to a certain level or more. This increases the flow velocity at the reverse osmosis membrane surface and lowers the impurity concentration in the vicinity of the membrane surface, thereby improving the permeate quality of the reverse osmosis membrane device to the extent that it does not adversely affect the electrodeionization device. be able to. Furthermore, it is possible to suppress the generation of scale on the reverse osmosis membrane surface due to the fluctuation of the supply water pressure to the reverse osmosis membrane device accompanying the temperature change of the hot water.

C / P is preferably set to a value at which the transmittance in the reverse osmosis membrane device is less than 2.5%. Therefore, in this embodiment, for example, the transmittance can be measured by measuring the quality of the feed water and the permeated water of the reverse osmosis membrane device, and C / P can be determined based on the measured transmittance. . In the present embodiment, C / P is preferably 4.5 or more, and more preferably 5.0 to 10.0. Thereby, the production | generation of the scale to a reverse osmosis membrane surface can be suppressed. If C / P is less than 5.0, scale is likely to be generated on the film surface, and if it exceeds 10.0, the pump needs to be enlarged.
In the present specification, the transmittance refers to (C _p / C _f ) × 100 when the impurity concentration (as CaCo ₃ ) in the feed water of the reverse osmosis membrane device is C _f and that in the permeated water is C _p. It is a value indicated by (%).

C / P in the temperature raising step and the hot water sterilization step is preferably adjusted by the opening degree of the valve V4. The valve 15 can be adjusted by the control device 15 based on the output of the pressure sensor 14 using the valve V4 as an electromagnetic valve having a variable opening. Further, a flow rate measurement sensor, a pressure sensor, and the like (not shown) may be interposed in the concentrated water pipe of the reverse osmosis membrane device, and the opening degree of the valve V4 can be controlled based on the outputs of the flow rate measurement sensor, the pressure sensor, and the like.
Also, a bypass line for bypassing the valve V4 is provided, and an opening variable valve is provided in the bypass line. The opening variable valve is fixed at a certain opening in advance, and this opening when the valve is turned on. It is also possible to adjust C / P by on / off control so that

  In particular, the permeability is less than 2.5% based on the quality of the permeated water and concentrated water of the reverse osmosis membrane device during the hot water sterilization process, that is, when the temperature of the circulating water is approximately the highest. It is preferable to determine the opening degree of the valve V4 so as to determine C / P and maintain the C / P constant. In this case, it is possible to further simplify the configuration and operation of incidental facilities (valves, pumps, pipes, etc.) for the hot water sterilization treatment.

  The electrodeionization device preferably applies a voltage when the circulating water temperature is 40 ° C. or lower in order to suppress deterioration of the quality of the circulating water, and the circulating water temperature is reduced in order to reduce the load on the electrodeionization device. When the temperature exceeds 40 ° C., it is preferable not to apply a voltage.

  Although the hot water sterilization process time varies depending on the temperature of the hot water, it is preferably performed for about 20 to 60 minutes after the temperature rise in order to perform sufficient sterilization. For example, it may be about 45 minutes when circulating hot water at 60 ° C., about 30 minutes when circulating hot water at 80 ° C., and about 20 minutes when circulating hot water at 90 ° C. preferable.

[Cooling process]
The production of pure water by the pure water production apparatus 1 is performed after the system is cooled to a temperature suitable for pure water production after hot water circulation. Therefore, in this embodiment, it is preferable to perform the temperature-falling process which cools the system of the pure water manufacturing apparatus 1 by reducing the temperature of circulating water after a hot-water sterilization process.

  The temperature lowering process is conventionally performed by a method of supplying cold water to the heat exchanger 11.

  In the present embodiment, in the temperature lowering step, the unheated raw water is circulated to the treatment line and the circulation line while supplying the raw water tank, and at least a part of the concentrated water of the reverse osmosis membrane device is discharged out of the system. Cooling.

  At this time, it is preferable that the raw water supply flow rate and the concentrated water discharge flow rate of the reverse osmosis membrane device be the same amount, that is, the water storage amount of the raw water tank 10 is kept constant.

Specifically, the valve V <b> 2 is opened and new unheated raw water is supplied to the raw water tank 10. The newly supplied unheated raw water is circulated to the circulation line through the pump P1 together with the hot water circulating. The valve V3 is opened, the opening of the valve V4 is adjusted, and the concentrated water of the reverse osmosis membrane device 12 is discharged out of the system at the same flow rate as the raw water supply flow rate supplied to the raw water tank.
In this case, since the amount of water retained in the system can be made constant, damage to the electrodeionization device due to, for example, rapid temperature drop can be prevented, and the temperature drop time can be shortened.

  The opening degree of the valve V4 can be adjusted by the control device 15 using the output of the pressure sensor 14. In addition, a flow rate measurement sensor (not shown) may be interposed in the concentrated water pipe of the reverse osmosis membrane device, and the opening degree of the valve V4 can be controlled by the control device 15 by the output of the flow rate measurement sensor.

  Further, a water storage level sensor for detecting the amount of water stored in the raw water tank 10 may be installed, and the opening degree of the valve V4 may be adjusted by the control device 15 based on the output of the water storage level sensor.

  In the temperature lowering step, it is preferable to supply raw water while keeping C / P constant as in the temperature rising step and the hot water sterilization step. Thereby, the flow rate on the reverse osmosis membrane surface of the reverse osmosis membrane device can be set to a certain level or more, and scale formation on the reverse osmosis membrane can be suppressed. Further, since the flow rate of the concentrated water can be made constant, higher temperature circulating water in the system can be discharged out of the system at a constant flow rate, and the temperature lowering time can be shortened.

  Moreover, it is preferable to raise the pressure of circulating water with the pump P2 so that the pressure of the permeated water of the reverse osmosis membrane apparatus 12 may become constant with the fall of the temperature of circulating water.

  When cooling the system, the circulating water may be cooled by supplying cold water to the heat exchanger 11 at the same time. When the system is cooled excessively, steam or the like is supplied to the heat exchanger 11. You may heat. In this case, the temperature drop rate can be maintained stably.

  Thus, in the sterilization method of the present embodiment, raw water can be used to collectively sterilize the reverse osmosis membrane device and the electrodeionization device, and the state in the system during the sterilization treatment can be steady. And sterilization efficiency can be improved. Further, it is possible to omit the cooling water for cooling the temperature, the apparatus for introducing the cooling water into the heat exchanger, the piping, and the like, and the temperature cooling time can be shortened. Therefore, a significant cost reduction is possible, which is economically advantageous.

Next, the present invention will be described in detail using examples and comparative examples.
The apparatus and conditions used in the examples and comparative examples are as follows.

Raw water: Atsugi city water treated with activated carbon device and prefilter.
Raw water tank 10: Capacity 1,000L,
Reverse osmosis membrane device 12: Trade name Duratherm RO 8040 HF, two membrane modules manufactured by GE, USA
Electrodeionization device 13: trade name MK-3 mini HT manufactured by GE USA,

[Example 1]
The pure water production apparatus 1 shown in FIG. 1 was sterilized.
In the water draining process, the raw water is heated until the temperature measured by the temperature measuring means 16 reaches 40 ° C., and at the same time, part of the concentrated water in the reverse osmosis membrane device 12 until the amount of water in the raw water tank becomes 25% of that during normal operation. Was discharged.

  The sterilization process is performed until the temperature measured by the temperature measuring means 16 reaches 90 ° C. at a temperature rising rate of 1 ° C./minute in the temperature raising step, and the hot water sterilization step circulates this hot water. I went. At this time, the output of the pressure sensor 14 was input to the control device 15, and the rotation speed of the pump P1 was adjusted so that the pressure of the permeated water of the reverse osmosis membrane device became a constant value of 0.15 ± 0.01 MPa.

  Next, the temperature drop rate is set to 1 ° C./min, the raw water is supplied to the raw water tank 10, and the opening of the valve V4 is set so that the amount of raw water introduced and the amount of concentrated water in the reverse osmosis membrane device to be discharged are the same. While controlling, the system was cooled until the temperature measured by the temperature measuring means 16 reached 27 ° C.

  The amount of water retained in the system at the time of the sterilization treatment was 330 L, and a spray ball was installed at the connection part between the circulation line and the raw water tank so that the hot water was in contact with the upper wall surface of the raw water tank. Further, the electrodeionization apparatus applied a voltage when the supply water temperature was 40 ° C. or lower, and stopped applying the voltage when the supply water temperature exceeded 40 ° C.

  Next, after introducing the raw water into the raw water tank, the process of producing pure water for pharmaceuticals and the hot water sterilization treatment were alternately repeated 150 times.

  At this time, a thermometer was placed at the outlet of the raw water tank to measure the supply water temperature of the electrodeionization apparatus. FIG. 2 shows the raw water tank outlet water temperature of the first hot water sterilization and the permeated water quality of the reverse osmosis membrane device. In FIG. 2, 0 to 35 minutes is a water draining step, 35 to 100 minutes is a temperature raising step, 100 to 130 minutes is a hot water sterilization step, and 130 to 220 minutes is a temperature lowering step.

  In Example 1, while the hot water sterilization treatment was repeated 150 times, the quality of the circulating water and the flow rate fluctuation during the hot water sterilization treatment were almost the same as the first time, and the heat was increased with the same temperature increase / decrease time as the first time. Water sterilization treatment could be performed. In particular, the conductivity of the treated water of the electrodeionization apparatus was able to maintain a water quality of 1.0 μS / cm or less even after 150 hot water sterilizations. The number of viable bacteria in the collected water immediately after the valve V1 after the 150th hot water sterilization was 0 / mL, and sufficient hot water sterilization was possible.

Moreover, when the integrated amount of the hardness supplied to the electrodeionization apparatus is calculated from the conductivity of the water supplied to each water treatment apparatus through the hot water sterilization treatment and the raw water tank storage amount, 3.5 mg (as CaCO ₃ ) Met.

[Comparative Example 1]
In Example 1, the pure water production apparatus 1 was sterilized under the same conditions as Example 1 except that the opening degree of the valve V4 was not controlled.

  FIG. 3 shows the temperature of the raw water tank outlet water at the first hot water sterilization and the quality of the permeated water of the reverse osmosis membrane device in Comparative Example 1. In FIG. 3, 0 to 85 minutes is a water draining process, 85 to 140 minutes is a temperature raising process, 140 to 170 minutes is a hot water sterilization process, and 170 to 290 minutes is a temperature lowering process.

In Comparative Example 1, while the hot water sterilization treatment was repeated 50 times, the quality of the circulating water and the flow rate fluctuation during the hot water sterilization treatment were almost the same as the first time. Although the water sterilization treatment could be performed, the test was stopped because the treated water conductivity of the electrodeionization device of the electrodeionization device exceeded 1.0 μS / cm after the 50th hot water sterilization.
Further, when the integrated amount of hardness supplied to the electrodeionization device is calculated from the conductivity of the water supplied to each water treatment device and the raw water tank storage amount through the hot water sterilization treatment, 4.8 mg (as CaCO ₃ )Met.

  In each figure, the reverse osmosis membrane device is abbreviated as RO.

  In Example 1, since the sterilization method and pure water production apparatus of the present invention are used, the temperature lowering process time (70 minutes) is shortened compared to Comparative Example 1 (100 minutes). This also shortens the time for stopping the application of voltage to the electrodeionization device, thereby reducing the total amount of hardness components supplied to the electrodeionization device and extending the life of the electrodeionization device. it can.

  Further, in Example 1, the quality of water supplied to the electrodeionization apparatus (that is, RO permeate quality) from the temperature raising process to the temperature lowering process is maintained at 20 μS / cm or less in terms of conductivity. The standard is not exceeded. Therefore, deterioration of the electrodeionization apparatus can be suppressed.

  Moreover, in Example 1, it turns out that the lifetime of a pure water manufacturing apparatus is extended, reducing the viable count in a pure water manufacturing apparatus to less than predetermined value.

Moreover, in the pure water manufacturing apparatus used in Example 1, when performing cold temperature supply to a heat exchanger at a temperature-falling process, members, such as piping, an automatic valve, a temperature controller, a temperature detector, are further included. However, in Example 1, these members can be omitted. In Example 1, when cold water is used in the temperature lowering step, the total amount of cold water required is 1000 L, but in Example 1, it is not necessary to use this cold water.
Therefore, compared with the case where these members are used, the cost can be reduced by about 50% per pure water production apparatus, which is very advantageous economically.

Thus, according to the hot water sterilization method and the pure water production apparatus of the embodiment, sterilization treatment can be performed using raw water, and therefore, the use of cooling equipment, piping, and cooling water is omitted. Can do. Furthermore, the temperature drop time can be shortened to improve the sterilization efficiency, thereby reducing damage to each water treatment device.
In addition, the temperature and flow rate at which the system is sufficiently sterilized can be stably maintained, damage to the electrodeionization apparatus can be reduced, and the life of the pure water production apparatus can be extended.

  DESCRIPTION OF SYMBOLS 1 ... Pure water manufacturing apparatus, 10 ... Raw water tank, 11 ... Heat exchanger, 12 ... Reverse osmosis membrane apparatus, 13 ... Electrodeionization apparatus, 14 ... Pressure sensor, 15 ... Control apparatus, 16 ... Temperature measuring means.

Claims (7)

A pump, a heat exchanger, a reverse osmosis membrane device, and an electrodeionization device are sequentially provided along a processing line connecting the raw water tank and the pure water tank or the use point, and the reverse osmosis membrane device and the electrodeionization device. A sterilization method for a pure water production apparatus comprising a circulation line for connecting each outlet side pipe and the raw water tank via an open / close valve,
After circulating hot water through the treatment line and the circulation line,
Pure water characterized in that while supplying unheated raw water to the raw water tank, the concentrated water of the reverse osmosis membrane device is discharged out of the system and the unheated raw water is circulated through the treatment line and the circulation line. A method for sterilizing manufacturing equipment.   The method for sterilizing a pure water production apparatus according to claim 1, wherein the supply flow rate of the unheated raw water and the discharge flow rate of the concentrated water from the reverse osmosis membrane device are the same.   Concentrated water of the reverse osmosis membrane device is provided by interposing an opening variable valve in the concentrated water discharge pipe of the reverse osmosis membrane device, supplying the unheated raw water and adjusting the opening of the variable opening valve. 3. The method for sterilizing a pure water producing apparatus according to claim 1, wherein the discharge flow rate is adjusted.   Further, a pressure sensor is disposed in the permeate pipe of the reverse osmosis membrane device of the treatment line, and the pressure sensor is configured to circulate hot water to the treatment line and the circulation line using the pump as a variable speed pump. 4. The method for sterilizing a pure water producing apparatus according to claim 1, wherein the rotational speed of the variable speed pump is controlled so that the output of the water is constant. 5.   The supply of the raw water to the raw water tank is stopped, the raw water stored in the raw water tank is circulated through the circulation line, and at least a part of the raw water is discharged out of the system while the raw water is discharged by the heat exchanger. The method for sterilizing a pure water producing apparatus according to any one of claims 1 to 4, wherein the hot water is generated by heating.   6. The method for sterilizing a pure water producing apparatus according to any one of claims 1 to 5, wherein the temperature of the hot water is 60 ° C or higher. A pump, a reverse osmosis membrane device, and an electrodeionization device are provided in this order along a processing line connecting the raw water tank and the pure water tank or the use point, and the concentrated water pipe of the reverse osmosis membrane device and the concentration of the electrodeionization device. A pure water production apparatus comprising a circulation line for connecting a water pipe, an electrode water pipe, and a treated water pipe of the electrodeionization device through the open / close valve and the raw water tank,
A concentrated water discharge pipe provided by branching from the concentrated water pipe of the reverse osmosis membrane device via an opening degree variable valve;
A pressure sensor installed in a permeate pipe of the reverse osmosis membrane device of the treatment line;
When the unheated raw water is supplied to the raw water tank to cool the inside of the pure water production system, the supply flow rate of the unheated raw water and the discharge flow rate of the concentrated water of the reverse osmosis membrane device are the same. And a control device for controlling the opening degree of the opening degree variable valve interposed in the concentrated water discharge pipe by the output of the pressure sensor.

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