Water treatment device and operation method therefor

Abstract

A water treatment device 1 comprises: a plurality of ultrafiltration membrane devices 10, 20 that each have at least one ultrafiltration membrane module 11-13, 21-23; and a steam introduction means L20 that introduces steam in parallel to the plurality of ultrafiltration membrane devices 10, 20.

Description

Water treatment device and method for operating same

[0001] The present invention relates to a water treatment device and a method for operating the same.

[0002] In recent years, in order to achieve energy efficiency and economic efficiency, ultrafiltration (UF) membrane devices have been used instead of distillers to produce pure water (e.g., purified water and water for injection) for pharmaceutical manufacturing. In such pure water production systems, sterilization treatment is periodically performed using high-temperature (e.g., 121°C or higher) steam to sterilize the system in order to prevent the growth of bacteria and microorganisms. However, the introduction of high-temperature steam into the UF membrane device can cause deterioration of the UF membrane. Therefore, a method for suppressing deterioration of the UF membrane due to steam sterilization treatment has recently been proposed (see, for example, Patent Document 1).

[0003] Patent No. 7365479

[0004] In a pure water production system equipped with a UF membrane device, in order to prevent deterioration or damage to the UF membrane due to a sudden temperature rise, a preheating process is performed by circulating hot water through the system before performing steam sterilization, thereby raising the temperature within the system to a predetermined temperature. However, steam is generally introduced into the pure water production system from a predetermined position within the system, and the introduction range is gradually expanded. Therefore, particularly when multiple UF membrane devices are installed, the time it takes for steam to reach the UF membrane device farther from the steam introduction position after hot water is discharged is inevitably longer, and air cooling during that time may occur, which may result in a sudden temperature rise due to the subsequent introduction of steam.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a water treatment device and an operating method thereof that suppress deterioration and damage to ultrafiltration membranes that occur during steam sterilization.

[0006] In order to achieve the above-mentioned object, the water treatment device of the present invention has a plurality of ultrafiltration membrane devices, each having at least one ultrafiltration membrane module, and a steam introducing means for introducing steam into the plurality of ultrafiltration membrane devices in parallel.

[0007] In addition, the method for operating a water treatment device of the present invention is a method for operating a water treatment device having a plurality of ultrafiltration membrane devices, each having at least one ultrafiltration membrane module, and includes a step of introducing steam into the plurality of ultrafiltration membrane devices in parallel and sterilizing the plurality of ultrafiltration membrane devices with the steam.

[0008] According to the present invention, deterioration and damage to the ultrafiltration membrane caused by steam sterilization can be suppressed.

[0009] Fig. 1 is a schematic configuration diagram of an apparatus for producing water for injection according to a first embodiment. Fig. 2 is a schematic configuration diagram of an ultrafiltration membrane device according to the first embodiment. Fig. 3 is a schematic configuration diagram showing a modified example of the apparatus for producing water for injection according to the first embodiment. Fig. 4 is a schematic configuration diagram of an apparatus for producing water for injection according to a second embodiment. Fig. 5 is a schematic configuration diagram of an apparatus for producing water for injection according to a third embodiment.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, the water treatment device of the present invention will be exemplified as an apparatus for producing pure water used in pharmaceutical production, specifically, an apparatus for producing water for injection by treating purified water, but the present invention is not limited thereto. In addition, in this specification, an apparatus for producing water for injection including two ultrafiltration (UF) membrane devices, each including three UF membrane modules, is exemplified, but the present invention is not limited thereto. The number of UF membrane devices constituting the apparatus for producing water for injection may be three or more, and the number of UF membrane modules constituting each UF membrane device may be two or less or four or more. Furthermore, multiple UF membrane devices may each have a different number of UF membrane modules. In this specification, purified water refers to water obtained by purifying ordinary water using ion exchange, reverse osmosis (RO), ultrafiltration (UF), or a combination thereof. Water for injection refers to purified water or water that has been appropriately pretreated and is treated by distillation or ultrafiltration (RO / UF) to be suitable for pyrogen (endotoxin) testing and viable bacteria testing. Examples of such purified water and water for injection include those specified in the Japanese Pharmacopoeia.

[0011] (First embodiment) Fig. 1 is a schematic diagram of an apparatus for preparing water for injection according to a first embodiment of the present invention. Fig. 2 is a schematic diagram of an ultrafiltration membrane device that constitutes the apparatus for preparing water for injection of this embodiment. Note that the configurations of the apparatus for preparing water for injection and the ultrafiltration membrane device shown in the figures are merely examples and do not limit the present invention, and needless to say can be changed as appropriate depending on the purpose, application, and required performance of the apparatus.

[0012] The injection water production apparatus 1 is an apparatus that produces injection water by sterilizing purified water, which is the water to be treated, by ultrafiltration, and has a purified water tank 2, a first UF membrane device 10, and a second UF membrane device 20.

[0013] The first UF membrane device 10 and the second UF membrane device 20 each have a UF membrane that separates the water to be treated into permeate and concentrate, and are connected in series so that the permeate separated by the first UF membrane device 10 is supplied to the second UF membrane device 20 as the water to be treated. Connecting the first UF membrane device 10 and the second UF membrane device 20 in series not only enables the production of treated water (water for injection) of better water quality, but also provides a fail-safe function in case the UF membrane of the first UF membrane device 10 is damaged. The detailed configuration of the UF membrane devices 10 and 20 will be described later. Although not described in detail here, water quality detection means such as a conductivity meter, a total organic carbon (TOC) meter, a particle meter, a microorganism measuring device, or an endotoxin measuring device may be provided near the outlet of each of the UF membrane devices 10 and 20 to check the water quality of the resulting permeate.

[0014] The first UF membrane device 10 is connected to a first water supply line L1 that supplies purified water from the purified water tank 2 to the first UF membrane device 10, a second water supply line (supply line) L2 that passes permeated water from the first UF membrane device 10 (hereinafter also referred to as "primary permeated water") and supplies it to the second UF membrane device 20, and a primary concentrated water line L3 that passes concentrated water from the first UF membrane device 10 (hereinafter also referred to as "primary concentrated water") and returns it to the purified water tank 2. The second UF membrane device 20 is also connected to a water supply line L4 that passes permeated water from the second UF membrane device 20 (hereinafter also referred to as "secondary permeated water") and supplies it to a water tank for injection (not shown) as water for injection, and a secondary concentrated water line L5 that passes concentrated water from the second UF membrane device 20 (hereinafter also referred to as "secondary concentrated water") and returns it to the purified water tank 2. Although not shown, the primary concentrated water line L3 is connected to a drain line for discharging a portion of the primary concentrated water to the outside during normal operation (production of water for injection) of the water for injection producing apparatus 1. Similarly, although not shown, the water supply line L4 (specifically, downstream of the junction with permeate lines L4a and L4b, described below) is connected to a return line for returning and circulating the water for injection obtained in the second UF membrane device 20 to the purified water tank 2 when there is no request to collect water from the water for injection tank. In addition, a purified water supply line L6 is connected to the purified water tank 2, and purified water is supplied from a purified water producing apparatus (not shown) as needed.

[0015] A pressure pump 3 is provided on the first water supply line L1, and a booster pump 4 is provided on the second water supply line L2. A heat exchanger 5 is also provided on the primary concentrate line L3. The pressure pump 3 pressurizes the purified water in the purified water tank 2 and supplies it to the first UF membrane device 10. The booster pump 4 boosts the pressure of the primary permeate from the first UF membrane device 10 and supplies it to the second UF membrane device 20. The heat exchanger 5 is used to generate hot water for heat sterilization during hot water sterilization, which is performed periodically between normal operations to reduce the number of viable bacteria in the system, and also to generate hot water for preheating during steam sterilization, which will be described later. Furthermore, the heat exchanger 5 may be used to heat the purified water or water for injection in the system so that the water is drawn into the water for injection tank at a high temperature (e.g., 80°C or higher). Although not shown, temperature sensors are provided near the inlet and outlet of the heat exchanger 5 to confirm that the temperature in the system has risen to a predetermined temperature in the above-mentioned cases.

[0016] A bypass line L7 is connected to the first feedwater line L1, branching off from the first feedwater line L1 downstream of the booster pump 3 and joining the primary concentrated water line L3 upstream of the heat exchanger 5. The bypass line L7 is provided with an on-off valve V1 that is closed during normal operation and is opened, for example, when hot water is produced by the heat exchanger 5. A reflux line L8 is connected to the secondary concentrated water line L5, branching off from the secondary concentrated water line L5 and joining the second feedwater line L2 upstream of the booster pump 4. This allows a portion of the secondary concentrated water to be refluxed upstream of the booster pump 4 during normal operation, thereby ensuring the minimum amount of concentrated water required for the second UF membrane device 20 (the minimum flow rate of secondary concentrated water to be flowed through the secondary concentrated water line L5) even when the flow rate of the primary permeate from the first UF membrane device 10 is insufficient. In addition, if the flow rate of the primary permeate from the first UF membrane device 10 is sufficient to ensure such a minimum amount of concentrated water, the booster pump 4 and the reflux line L8 do not necessarily have to be provided.

[0017] Furthermore, the first water supply line L1, the second water supply line L2, the primary concentrated water line L3, the secondary concentrated water line L5, and the reflux line L8 are each connected to discharge lines L11 to L14 for discharging hot water, steam, and condensed water introduced into the system during the steam sterilization process described below.

[0018] Specifically, an on-off valve V2 is provided downstream of the connection with the bypass line L7 in the first water supply line L1, and a first discharge line L11 is connected to the downstream side via an on-off valve V3. Two on-off valves V4 and V5 are provided adjacent to each other in the second water supply line L2 (specifically, upstream of the connection with the reflux line L8), and a second discharge line L12 is connected therebetween via an on-off valve V6. An on-off valve V7 is provided upstream of the connection with the bypass line L7 in the primary concentrated water line L3, and a third discharge line L13 is connected upstream of the on-off valve V7 via an on-off valve V8. An on-off valve V9 is provided in the secondary concentrated water line L5 (although it is shown separated in the figure) near the purified water tank 2, and a fourth discharge line L14 is connected upstream of the on-off valve V9 via an on-off valve V10. An on-off valve V11 is provided near the downstream end of the return line L8 (specifically, the connection point with the second water supply line L2), and a fifth discharge line L15 is connected to the upstream side of the on-off valve V11 via an on-off valve V12.

[0019] The second discharge line L12 is provided with a temperature sensor 6 and an on-off valve CV1 with a micro-hole, and the fifth discharge line L15 is also provided with a temperature sensor 7 and an on-off valve CV2 with a micro-hole. The on-off valves CV1 and CV2 with a micro-hole are on-off valves formed with micro-holes that allow only condensed water to pass through even when fully closed. Examples of such on-off valves include grooved diaphragm valves and perforated ball valves. Although not shown, the first, fourth, and fifth discharge lines L11, L14, and L15 are also provided with temperature sensors and on-off valves with a micro-hole, respectively, similar to the second and third discharge lines L12 and L13.

[0020] The first UF membrane device 10 has multiple (three in the illustrated example) UF membrane modules 11-13 connected in parallel, and the second UF membrane device 20 also has multiple (three in the illustrated example) UF membrane modules 21-23 connected in parallel. Each UF membrane module 11-13, 21-23 is a hollow fiber membrane module in which multiple hollow fiber UF membranes (hereinafter also referred to as "hollow fiber membranes") are bundled and packed into a cylindrical housing. The filtration method is an internal pressure crossflow system in which water to be treated is supplied from the inside of the hollow fiber membrane parallel to the membrane surface, permeated water is extracted from the outside, and the water that does not permeate the membrane is discharged as concentrated water. Each UF membrane module 11-13, 21-23 has a water to be treated inlet and a concentrated water outlet at both ends of its length, and is arranged vertically with the water to be treated inlet facing downward and the concentrated water outlet facing upward. Each UF membrane module 11-13, 21-23 has two permeate outlets, one at the top and one at the bottom, on its side. Arranging the UF membrane modules 11-13, 21-23 in this manner is advantageous not only for efficiently discharging the hot water introduced during the steam sterilization treatment described below, but also for preventing air pockets from forming within the hollow fiber membranes when operation is subsequently restarted, since the water to be treated flows upward. Note that the UF membrane modules 11-13, 21-23 are not limited to internal pressure hollow fiber membrane modules, but may also be external pressure modules in which the water to be treated is supplied from the outside of the hollow fiber membranes and the permeate is extracted from the inside.

[0021] In the first UF membrane device 10, a first feedwater line L1 and a primary concentrate line L3 are connected to the bottom inlets for treated water and the top concentrate outlets of the UF membrane modules 11-13, respectively. An upper permeate line L2a is connected to the permeate outlets at the upper side of each of the UF membrane modules 11-13, and a lower permeate line L2b is connected to the permeate outlets at the lower side. The two permeate lines L2a and L2b are joined and connected to a second feedwater line L2. A primary discharge line L31 is connected to the first feedwater line L1 (specifically, its downstream end) via an on-off valve V31, and a secondary discharge line L32 is connected to the lower permeate line L2b via an on-off valve V32. Each discharge line L31 and L32 is provided to discharge hot water and steam introduced into the UF membrane modules 11-13 during steam sterilization, which will be described later. In addition, a flow control valve V33 is provided downstream of the connection point of the lower permeate line L2b with the secondary discharge line L32 to adjust the flow rate balance of the permeate flowing through the two permeate lines L2a, L2b.

[0022] In the second UF membrane device 20, a second feedwater line L2 and a secondary concentrate line L5 are connected to the bottom inlets for treated water and the top concentrate outlets of the UF membrane modules 21-23, respectively. An upper permeate line L4a is connected to the permeate outlets at the upper side of the UF membrane modules 21-23, and a lower permeate line L4b is connected to the permeate outlets at the lower side. The two permeate lines L4a and L4b are joined and connected to the water supply line L4. A primary discharge line L33 is connected to the second feedwater line L2 (specifically, its downstream end) via an on-off valve V34, and a secondary discharge line L34 is connected to the lower permeate line L4b via an on-off valve V35. Each discharge line L33 and L34 is provided to discharge hot water, steam, and condensed water introduced into the UF membrane modules 21-23 during steam sterilization, as described below. In addition, a flow rate adjustment valve V36 is provided downstream of the connection point of the lower permeated water line L4b with the secondary discharge line L34 to adjust the flow rate balance of the two permeated waters L4a, L4b.

[0023] During normal operation of the water for injection manufacturing apparatus 1, a water sampling process is performed in which purified water stored in the purified water tank 2 is sequentially treated by the UF membrane devices 10 and 20, and the resulting water for injection is supplied to a water for injection tank (not shown) through a water supply line L4. At this time, a portion of the primary concentrate from the first UF membrane device 10 is discharged to the outside through a drain line (not shown) to prevent impurities from concentrating within the system, and the remainder is returned to the purified water tank 2 through a primary concentrate line L3. However, when there is no request to sample water from the water for injection tank and circulation operation is performed in which all of the water for injection obtained by the second UF membrane device 20 is returned to the purified water tank 2, there is no risk of the above-mentioned concentration proceeding, and therefore all of the primary concentrate may be returned to the purified water tank 2. Meanwhile, a portion of the secondary concentrate from the second UF membrane device 20 is returned to the upstream side of the booster pump 4 through a reflux line L8, and the remainder is returned to the purified water tank 2 through a secondary concentrate line L5. As a result, as described above, the minimum amount of concentrated water required for the second UF membrane device 20 can be ensured, and the number of UF membrane modules constituting the first UF membrane device 10 can be reduced.

[0024] In the water for injection manufacturing apparatus 1 for producing water for injection used in pharmaceutical manufacturing, etc., a sterilization process is periodically performed between the above-mentioned normal operations to sterilize the system, including the UF membrane devices 10 and 20, using steam at 121°C or higher to prevent the growth of bacteria and microorganisms. To this end, the water for injection manufacturing apparatus 1 has a steam introduction line (steam introduction means) L20 for introducing steam into the system. The steam introduction line L20 branches into two lines, connected to the primary concentrate line L3 and the secondary concentrate line L5 via on-off valves V21 and V22, respectively. This allows steam to be introduced in parallel to the first and second UF membrane devices 10 and 20, as will be described in detail below. Note that "introducing in parallel" as used herein includes not only completely simultaneous introduction but also at least partial temporal overlap. The series of steps in this steam sterilization process will be described in detail below.

[0025] (Preheating Step) The preheating step is a step of raising the temperature in the system to a predetermined temperature, for example, 80 to 90°C, in preparation for sterilizing the inside of the system of the water for injection manufacturing apparatus 1 with steam, in order to prevent a sudden rise in temperature due to the introduction of high-temperature steam. However, if high-temperature water (for example, water at 80 to 90°C) is circulated in the system during normal operation, the preheating step can be omitted.

[0026] During the preliminary heating step, water is not drawn into the water for injection tank, and accordingly, the water for injection is produced in the apparatus for water for injection 1 in the same manner as during normal operation, except that the primary concentrated water from the first UF membrane device 10 is not discharged to the outside. At the same time, a heat medium (e.g., steam) is supplied to the heat exchanger 5, thereby heating the primary concentrated water returned to the purified water tank 2, and the water circulating within the system of the apparatus for water for injection 1 is also heated and maintained at, for example, 80 to 90°C. In this way, the hot water circulates within the system, raising the temperature of the entire system to approximately the same temperature. At this time, the on-off valve V1 of the bypass line L7 is opened, and a portion of the hot water flowing through the first water supply line L1 is returned to the purified water tank 2, thereby enabling the water in the purified water tank 2 to be efficiently heated even when the capacity of the purified water tank 2 is relatively large. In addition, when steam is used as the heat medium for the heat exchanger 5, the steam inlet line L20 may be branched and connected to the heat exchanger 5, thereby supplying steam to the heat exchanger 5 from the steam inlet line L20.

[0027] Thereafter, the on-off valve V2 of the first water supply line L1, the on-off valve V7 of the primary concentrated water line L3, and the on-off valve V9 of the secondary concentrated water line L5 are closed, and the booster pump 4 is stopped, so that hot water is continuously circulated only between the purified water tank 2 and the bypass line L7, and the circulation of hot water in other areas is stopped. Then, the on-off valves V3, V6, V8, V10, V12, V31, V32, V34, and V35 of each discharge line L11-L15 and L31-L34 are opened, and clean air is introduced, for example, through a clean air inlet line (not shown). This pushes out the hot water in the system, excluding the circulation path, and discharges it to the outside through each discharge line L11-L15 and L31-L34. In addition, a return line (not shown) connected to the water supply line L4 is also connected to a discharge line similar to each of the discharge lines L11 to L15, L31 to L34, and the hot water in the return line is also discharged to the outside through that discharge line.

[0028] (Steam sterilization process) The steam sterilization process is a process of sterilizing the system of the water for injection manufacturing apparatus 1 with steam, specifically, a process of introducing steam into the system through the primary concentrated water line L3 and the secondary concentrated water line L5 and maintaining it for a certain period of time.

[0029] When it is confirmed that hot water has stopped being discharged from each of the discharge lines L11 to L15, L31 to L34 and the introduction of clean air through the clean air introduction line is stopped, the steam sterilization process is started. In the steam sterilization process, steam is first introduced into the first UF membrane device 10 and the second UF membrane device 20.

[0030] Specifically, the on-off valve V21 of the steam introduction line L20 is opened, and accordingly, the on-off valve V3 of the first discharge line L11, the on-off valve V4 of the second feedwater line L2, and the on-off valve V8 of the third discharge line L13 are closed, thereby introducing steam through the primary concentrated water line L3 into the first UF membrane device 10. The introduced steam flows through the primary sides of each of the UF membrane modules 11 to 13, and is then discharged from the first feedwater line L1 to the outside through the primary-side discharge line L31, and also passes through the secondary sides of each of the UF membrane modules 11 to 13, and is then discharged from the permeate lines L2a and L2b to the outside through the secondary-side discharge line L32. At the same time, the on-off valve V22 of the steam introduction line L20 is also opened, and accordingly, the on-off valve V5 of the second feedwater line L2, the on-off valve V10 of the fourth discharge line L14, the on-off valve V11 of the reflux line L8, and the on-off valve (not shown) of the water supply line L4 are closed, thereby introducing steam through the secondary concentrated water line L5 into the second UF membrane device 20. The introduced steam flows through the primary sides of each of the UF membrane modules 21 to 23, and is then discharged from the second feedwater line L2 to the outside through the primary-side discharge line L33, and also passes through the secondary sides of each of the UF membrane modules 21 to 23, and is then discharged from the permeate lines L4a and L4b to the outside through the secondary-side discharge line L34.

[0031] In this way, by introducing steam into the first UF membrane device 10 and the second UF membrane device 20 in parallel, the time from the end of the preheating step until the steam reaches the UF membrane of each UF membrane device 10, 20 can be shortened. As a result, the temperature drop of the UF membrane after the end of the preheating step is suppressed, and ultimately, a rapid temperature increase of the UF membrane due to the subsequent introduction of steam can be suppressed. As a method for introducing steam into the first UF membrane device 10 and the second UF membrane device 20 in parallel, for example, steam can be introduced vertically upward from the respective treated water inlets through the first water supply line L1 and the second water supply line L2. However, residual water is likely to remain near the treated water inlets, and it is difficult to push such residual water out with steam from below. As a result, repeated collisions between the residual water and steam occur, which may cause a water hammer and damage the UF membranes. Therefore, as in this embodiment, it is preferable that steam be introduced into the first UF membrane device 10 and the second UF membrane device 20 vertically downward from the respective concentrated water outlets through the primary concentrated water line L3 and the secondary concentrated water line L5. Furthermore, introducing steam vertically downward from the concentrated water outlets is also advantageous in that condensed water generated within the hollow fiber membranes of each UF membrane module 11-13, 21-23 can be efficiently discharged.

[0032] Thereafter, when the UF membrane devices 10, 20 have been sufficiently heated to the desired sterilization temperature (e.g., 121°C or higher), the micro-hole on-off valves (not shown) in the discharge lines L31-L34 of the UF membrane devices 10, 20 are closed. Whether the temperatures of the UF membrane devices 10, 20 have been sufficiently raised can be confirmed by checking whether the detected values ​​of the temperature sensors (not shown) provided in the discharge lines L31-L34 have reached or exceeded a predetermined value. In this way, the discharge of steam from the discharge lines L31-L34 of the UF membrane devices 10, 20 is stopped, and once only condensed water is being discharged, the introduction of steam into the remaining system is started so as to gradually expand the range of steam introduction.

[0033] Specifically, first, the on-off valve V4 of the second feedwater line L2 is opened, and steam introduced into the first UF membrane device 10 is discharged from the second feedwater line L2 to the outside through the second discharge line L12. As a result, steam is introduced into the portion of the second feedwater line L2 from the first UF membrane device 10 to the connection with the second discharge line L12 (hereinafter also referred to as the "upstream portion"). Then, when it is confirmed that the detection value of the temperature sensor 6 has reached a predetermined value or higher, i.e., that the upstream portion of the second feedwater line L2 has been sufficiently heated, the on-off valve V4 of the second feedwater line L2 is closed, and the inflow of steam from the upstream portion of the second feedwater line L2 to the second discharge line L12 is stopped. At the same time, the on-off valve V5 of the second water supply line L2 is opened, and the steam introduced into the second UF membrane device 20 is discharged from the second water supply line L2 to the outside through the second discharge line L12. As a result, steam is introduced into the portion of the second water supply line L2 from its connection with the second discharge line L12 to the second UF membrane device 20 (hereinafter also referred to as the "downstream portion"). Then, when it is confirmed that the detection value of the temperature sensor 6 has reached a predetermined value or higher, i.e., that the downstream portion of the second water supply line L2 has been sufficiently heated, the micro-hole on-off valve CV1 of the second discharge line L12 is closed so that only condensed water is discharged from the second discharge line L12. In this way, steam is introduced into the second water supply line L2 within the system of the water for injection manufacturing apparatus 1.

[0034] It is also possible that, even if the second feedwater line L2 is not provided with the on-off valves V4 and V5, steam can also be introduced into the second feedwater line L2 when steam is introduced into the first UF membrane device 10 and the second UF membrane device 20, as long as the second discharge line L12 is connected. However, when steam is introduced into the first and second UF membrane devices 10 and 20, the steam flowing in from the first UF membrane device 10 and the steam flowing in from the second UF membrane device 20 collide in the second feedwater line L2 connecting the two, which tends to form air pockets. As a result, steam may not flow sufficiently through the second discharge line L12, or steam may be more likely to flow in from only one of the first UF membrane device 10 and the second UF membrane device 20, which may result in insufficient temperature rise in the second feedwater line L2. Therefore, in order to suppress the above-mentioned collision of steam, it is preferable that the second water supply line L2 be provided with on-off valves V4 and V5 as a shut-off means for shutting off the flow of steam when steam is introduced into the first and second UF membrane devices 10 and 20.

[0035] Steam may be introduced into the second feedwater line L2 from either the upstream or downstream portion, or both simultaneously. However, if the on-off valves V4 and V5 of the second feedwater line L2 are simultaneously opened, as described above, steam may flow only through either the upstream or downstream portion. Therefore, it is not possible to determine whether the upstream or downstream portion has been sufficiently heated simply by the detection value of the temperature sensor 6 reaching a predetermined value. Therefore, it is preferable to introduce steam into the second feedwater line L2 separately from the upstream and downstream portions by switching the on-off valves V4 and V5 on and off, as in this embodiment.

[0036] Next, the on-off valve V12 of the fifth discharge line L15 is opened, and the steam that has flowed into the secondary concentrated water line L5 is discharged from the reflux line L8 through the fifth discharge line L15 to the outside, thereby introducing steam into the reflux line L8. Then, when it is confirmed that the detected value of the temperature sensor 7 has reached a predetermined value or higher, i.e., that the reflux line L8 has been sufficiently heated, the micro-hole on-off valve CV2 of the fifth discharge line L15 is closed so that only condensed water is discharged from the fifth discharge line L15. Note that the reflux line L8, like the second feedwater line L2, can also be considered a connecting line connecting the first UF membrane device 10 and the second UF membrane device 20. Therefore, if the reflux line L8 is not provided with the on-off valve V11, as in the case of the second feedwater line L2, there is a risk of air pockets being formed when steam is introduced into the first and second UF membrane devices 10, 20 due to collision between steam flowing in from the primary concentrated water line L3 of the first UF membrane device 10 and steam flowing in from the second UF membrane device 20 through the second feedwater line L2. In contrast, like the on-off valves V4, V5 of the second feedwater line L2, the on-off valve V11 functions as a shutoff means for shutting off the flow of steam in the reflux line L8, thereby preventing the formation of such air pockets.

[0037] Thereafter, the on-off valve V3 of the first discharge line L11, the on-off valve V8 of the third discharge line L13, and the on-off valve V10 of the fourth discharge line L14 are sequentially opened as shown below, thereby sequentially introducing pure water into the system of the apparatus for producing water for injection 1. However, the order in which the on-off valves V8, V10, and V12 are opened is not limited to the following.

[0038] That is, first, the on-off valve V3 of the first discharge line L11 is opened, and steam is introduced into the portion of the first feedwater line L1 from the first UF membrane device 10 to the connection with the first discharge line L11. Then, when it is confirmed that the temperature of that portion has risen sufficiently based on the detection result of a temperature sensor (not shown) provided in the first discharge line L11, the on-off valve with micro-holes (not shown) provided in the first discharge line L11 is closed so that only condensed water is discharged from the first discharge line L11. At the same time, the on-off valve V8 of the third discharge line L13 is opened, and steam is introduced into the portion of the primary concentrated water line L3 downstream of the connection with the steam inlet line L20. Then, when it is confirmed that the temperature of that portion has risen sufficiently based on the detection result of the temperature sensor (not shown) provided in the third discharge line L13, the on-off valve with micro-holes (not shown) provided in the third discharge line L13 is closed so that only condensed water is discharged from the third discharge line L13. At the same time, the on-off valve V10 of the fourth discharge line L14 is opened, and steam is introduced into the portion of the secondary concentrated water line L5 downstream of the connection with the steam inlet line L20. Then, when it is confirmed that the temperature of that portion has risen sufficiently based on the detection results of a temperature sensor (not shown) provided in the fourth discharge line L14, the on-off valve with microholes (not shown) provided in the fourth discharge line L14 is closed so that only condensed water is discharged from the fourth discharge line L14. Although not described in detail, steam is also introduced into a return line (not shown) connected to the water supply line L4 in the same manner as described above.

[0039] Steam is introduced into the system in this manner, and this state is maintained for a certain period of time, thereby carrying out sterilization of the water for injection manufacturing apparatus 1.

[0040] (Temperature-reducing step) The temperature-reducing step is a step of lowering the temperature in the system to a temperature at which water can be collected into the water for injection tank when normal operation of the water for injection manufacturing apparatus 1 is resumed after the steam sterilization step is completed.

[0041] After the steam introduction has been performed for a certain period of time, the on-off valves V21 and V22 of the steam introduction line L20 are closed, and the introduction of steam is stopped. Thus, the steam sterilization process is completed. For example, when the temperature in the system drops to 105°C or below, the temperature-lowering process is initiated. In the temperature-lowering process, the on-off valves V3, V6, V8, V10, V12, V31, V32, V34, and V35 of the discharge lines L11-L15 and L31-L34 are closed, and the on-off valve V2 of the first water supply line L1, the on-off valve V7 of the primary concentrated water line L3, and the on-off valve V9 of the secondary concentrated water line L5 are opened. Then, the booster pump 4 is activated, and the hot water that had been circulating between the purified water tank 2 and the bypass line L7 during the steam sterilization process flows through the system via the first water supply line L1, and the hot water is circulated in the same manner as during the preliminary heating process. Thereafter, the amount of heat medium supplied to the heat exchanger 5 is gradually reduced, or a portion of the circulating hot water is discharged to the outside, and accordingly, room temperature purified water is gradually supplied to the purified water tank 2 through the purified water supply line L6, thereby starting to cool the hot water. Then, when the circulating hot water has cooled to about room temperature, normal operation of the water for injection manufacturing apparatus 1 is resumed, and in response to a request to collect water from the water for injection tank, water for injection manufactured by the water for injection manufacturing apparatus 1 is supplied to the water for injection tank through the water supply line L4. Note that when high temperature water is circulated within the system during normal operation, cooling of the hot water can be omitted.

[0042] 3(a) and 3(b) are schematic diagrams showing modified examples of the apparatus for preparing water for injection according to the present embodiment, and correspond to FIG. 2. FIG.

[0043] The connection position of the second discharge line L12 to the second feedwater line L2 is not limited to a position distant from the first and second UF membrane devices 10 and 20, and may be, for example, a position close to the first UF membrane device 10. That is, as shown in FIG. 3( a), an on-off valve V4 may be provided close to the upstream end of the second feedwater line L2 (specifically, the junction with the permeate lines L2a and L2b), and the second discharge line L12 may be connected downstream thereof. In this case, the remaining on-off valve V5 provided in the above-described configuration may not be provided in the second feedwater line L2. Alternatively, although not shown, the second discharge line L12 may be connected to the second feedwater line L2 at a position close to the second UF membrane device 20. For example, an on-off valve V5 may be provided in the second supply water line L2 upstream of and close to the junction with the return line L8, and the second discharge line L12 may be connected near the upstream side of the on-off valve V5. In this case, the remaining on-off valve V4 provided in the above-described configuration may not be provided in the second supply water line L2. The number of second discharge lines L12 does not have to be one. For example, as shown in FIG. 3( b), two second discharge lines L12a, L12b may be connected to the second supply water line L2 close to each other. In this case, too, only one on-off valve V4 of the two on-off valves V4, V5 provided in the above-described configuration may be provided in the second supply water line L2 between their connections, and the remaining on-off valve V5 may not be provided.

[0044] These modified examples are advantageous in that steam can also be introduced into the second feedwater line L2 without any other operation as long as the on-off valve V4 (or on-off valve V5) is closed when steam is introduced into the first and second UF membrane devices 10, 20. In the modified example shown in Figure 3(a), it is preferable to confirm in advance by, for example, conducting a trial run, that the portion of the second feedwater line L2 upstream of the on-off valve V4 can be sufficiently heated by the steam introduced into the first UF membrane device 10 even when the on-off valve V4 is closed.

[0045] Although not shown, the connection position and number of the fifth discharge line L15 to the reflux line L8 may be changed, as in the case of the second discharge line L12 described above. That is, the on-off valve V11 may be provided near the upstream end of the reflux line L8 (specifically, the branch point with the secondary concentrated water line L5), and the fifth discharge line L15 may be connected downstream thereof. Alternatively, the on-off valve V11 and another on-off valve may be provided close to each other at positions away from the upstream and downstream ends of the reflux line L8, and the fifth discharge line L15 may be connected therebetween. Furthermore, two fifth discharge lines L15 may be connected close to each other at positions away from the upstream and downstream ends of the reflux line L8, with the on-off valve V11 sandwiched between them.

[0046] Second Embodiment Fig. 4 is a schematic diagram of an apparatus for preparing water for injection according to a second embodiment of the present invention. This embodiment differs from the first embodiment in that steam sterilization is also performed on the purified water tank. The following description will focus on this difference.

[0047] In this embodiment, the steam introduction line L20 is connected to the purified water tank 2 via an on-off valve V23. Accordingly, a sixth discharge line L16 is connected to the first water supply line L1 upstream of the pressure pump 3 via an on-off valve V13. Like the other discharge lines L11 to L15, the sixth discharge line L16 is provided to discharge hot water from the purified water tank 2 to the outside during the preliminary heating step and to discharge steam introduced into the purified water tank 2 to the outside during the steam sterilization step. Although not shown, the sixth discharge line L16 is also provided with a temperature sensor and an on-off valve with a microhole, like the other discharge lines L11 to L15.

[0048] Due to such changes in the configuration, the steps of the steam sterilization treatment in this embodiment differ from those in the first embodiment in the following respects.

[0049] That is, in the preliminary heating step, when the temperature in the system rises to a predetermined temperature due to the circulation of hot water, the on-off valve V2 in the first feedwater line L1, the on-off valve V7 in the primary concentrated water line L3, and the on-off valve V9 in the secondary concentrated water line L5 are left open, and the booster pump 4 and the pressure pump 3 are stopped. This stops all circulation of hot water in the system. Thereafter, the on-off valve V13 in the sixth discharge line L16 is opened, and when the hot water in the system is discharged to the outside, the hot water in the purified water tank 2 is similarly discharged to the outside via the sixth discharge line L16.

[0050] In the steam sterilization process, the on-off valve V23 of the steam inlet line L20 is opened, and the on-off valve V2 of the first feedwater line L1, the on-off valve V7 of the primary concentrated water line L3, and the on-off valve V9 of the secondary concentrated water line L5 are accordingly closed, thereby introducing steam into the purified water tank 2. When it is confirmed that the temperature of the purified water tank 2 has risen sufficiently based on the detection results of a temperature sensor (not shown) provided in the sixth discharge line L16, the on-off valve with microholes (not shown) provided in the sixth discharge line L16 is closed so that only condensed water is discharged from the sixth discharge line L16. The on-off valve V7 of the primary concentrated water line L3 and the on-off valve V9 of the secondary concentrated water line L5 are then opened, thereby introducing steam in parallel from the purified water tank 2 through the primary concentrated water line L3 and the secondary concentrated water line L5 to the first UF membrane device 10 and the second UF membrane device 20. This allows the purified water tank 2 to be sterilized while the UF membrane devices 10 and 20 are heated at the same time.

[0051] Furthermore, in the temperature-lowering step, when the on-off valve V23 of the steam inlet line L20 is closed to stop the introduction of steam, the inside of the system of the water for injection production apparatus 1 is first cooled by clean air introduced from a clean air inlet line (not shown) through the purified water tank 2. Thereafter, for example, when the temperature of the purified water tank 2 drops below 90°C, the introduction of clean air is stopped. Then, the supply of purified water to the purified water tank 2 begins through the purified water supply line L6, and normal operation of the water for injection production apparatus 1 is resumed. Specifically, the on-off valves V3, V6, V8, V10, V12, V13, V31, V32, V34, and V35 of each discharge line L11 to L16 and L31 to L34 are closed, and the pressure pump 3 and the booster pump 4 are started, thereby resuming normal operation in which the purified water in the purified water tank 2 is sequentially treated by the UF membrane devices 10 and 20. In addition, when replenishing purified water to the purified water tank 2, in order to prevent large temperature changes within the system, it is preferable to start replenishing with preheated purified water and then gradually lower its temperature.

[0052] (Third embodiment) Figure 5 is a schematic diagram of an apparatus for producing water for injection according to a third embodiment of the present invention. This embodiment differs from the first embodiment in that a first UF membrane device and a second UF membrane device are connected in parallel. The following description will focus on this difference.

[0053] In this embodiment, the first UF membrane device 10 and the second UF membrane device 20 are connected in parallel to each other between the first water supply line L1 and the water supply line L4. Specifically, the first water supply line L1 is connected to the treated water inlets of the first and second UF membrane devices 10, 20 via two branch water supply lines L21, L22, and the water supply line L4 is connected to the permeate outlets of the first and second UF membrane devices 10, 20 via two branch water supply lines L23, L24. In other words, in this embodiment, two branch water supply lines L21, L22 are provided to branch purified water flowing through the first water supply line L1 and supply it to the first and second UF membrane devices 10, 20, and two branch water supply lines L23, L24 are provided to allow permeate water from the first and second UF membrane devices 10, 20 to flow through and merge with the water supply line L4.

[0054] Accordingly, in this embodiment, the second water supply line L2 is omitted, and the on-off valves V4 and V5 and the second discharge line L12 that were provided in the second water supply line L2 are provided in the second branch water supply line L22, which is a connecting line connecting the first UF membrane device 10 and the second UF membrane device 20, similarly to the second water supply line L2. The booster pump 4 that was provided in the second water supply line L2 is also omitted, and accordingly, the fifth discharge line L15 is also omitted. In this embodiment, two on-off valves V14 and V15 are provided adjacent to each other in the second branch water supply line L24, which is a connecting line connecting the first UF membrane device 10 and the second UF membrane device 20, and a seventh discharge line L17 is connected therebetween via an on-off valve V16. The seventh discharge line L17 is provided with a temperature sensor 8 and a micro-hole on-off valve CV3, similarly to the second discharge line L12. In addition, the on-off valves V4, V5 and the second discharge line L12 may be provided in the first branch water supply line L21 instead of the second branch water supply line L22, and the on-off valves V14, V15 and the seventh discharge line L17 may be provided in the first branch water supply line L23 instead of the second branch water supply line L24.

[0055] The steam sterilization process in this embodiment is the same as that in the first embodiment, except that during the steam sterilization step, after steam is introduced into the first and second UF membrane devices 10 and 20, steam is introduced into the second branch water supply line L22 in the same procedure as for the second water supply line L2, and steam is introduced into the second branch water supply line L24. As with the second water supply line L2, steam is introduced into the second branch water supply line L24 by switching the on-off valves V14 and V15 between on and off, and this switching is performed based on the detection results of the temperature sensor 8 provided in the seventh discharge line L17. Also, as with the first embodiment, once it is confirmed that the temperature of the second branch water supply line L24 has been sufficiently increased, the micro-hole on-off valve CV3 in the seventh discharge line L17 is closed so that only condensed water is discharged from the seventh discharge line L17.

[0056] In this embodiment, as in the modified example of the first embodiment ( FIG. 3 ), the connection position and number of the second discharge line L12 relative to the second branch water supply line L22 may be changed. That is, an on-off valve V4 may be provided near the upstream end of the second branch water supply line L22 (specifically, the branch point with the first branch water supply line L21), and the second discharge line L12 may be connected near the downstream side thereof. In this case, an on-off valve V5 may not be provided in the second branch water supply line L22. Alternatively, an on-off valve V5 may be provided near the downstream end of the second branch water supply line L22 (specifically, the connection point with the first UF membrane module 21 of the second UF membrane device 20), and the second discharge line L12 may be connected near the upstream side thereof. In this case, an on-off valve V4 may not be provided in the second branch water supply line L22. Furthermore, two second discharge lines L12 may be connected to the second branch water supply line L22 in close proximity to each other. In this case, too, only the on-off valve V4 may be provided between the connection points, and the on-off valve V5 may not be provided.

[0057] The connection position and number of the seventh discharge line L17 to the second branch water supply line L24 may also be changed in a similar manner. That is, the on-off valve V14 may be provided near the upstream end of the second branch water supply line L24 (specifically, the connection point with the third UF membrane module 23 of the second UF membrane device 20), and the seventh discharge line L17 may be connected near the downstream side thereof. In this case, the on-off valve V15 may not be provided in the second branch water supply line L24. Alternatively, the on-off valve V15 may be provided near the downstream end of the second branch water supply line L24 (specifically, the junction with the first branch water supply line L23), and the seventh discharge line L17 may be connected near the upstream side thereof. In this case, the on-off valve V14 may not be provided in the second branch water supply line L24. Furthermore, two seventh discharge lines L17 may be connected to the second branch water supply line L22 in close proximity to each other. In this case, too, only the on-off valve V14 may be provided between these connecting portions, and the on-off valve V15 may not be provided.

[0058] In the above-described embodiment, an example has been described in which multiple UF membrane devices are connected in series or in parallel, but the connection configuration of multiple UF membrane devices is not limited to this, and a combination of series and parallel may also be used.

[0059] DESCRIPTION OF SYMBOLS 1 Water for injection manufacturing apparatus (water treatment apparatus) 4 Booster pump 6, 7 Temperature sensor 10 First UF membrane device 20 Second UF membrane device 11-13, 21-23 UF membrane module L2 Second water supply line (supply line) L3 Primary concentrated water line L5 Second concentrated water line L8 Reflux line L12 Second discharge line L17 Seventh discharge line L20 Steam introduction line (steam introduction means) L21, L22 Branch water supply line L23, L24 Branch water supply line V4, V5, V11, V14, V15 Opening and closing valve (shutoff means)

Claims

1. A water treatment device comprising: a plurality of ultrafiltration membrane devices, each having at least one ultrafiltration membrane module; and steam introducing means for introducing steam into the plurality of ultrafiltration membrane devices in parallel.

2. The water treatment device according to claim 1, further comprising a plurality of concentrated water lines through which concentrated water discharged from the plurality of ultrafiltration membrane devices is circulated, and the steam introduction means is capable of introducing steam into each of the plurality of ultrafiltration membrane devices through the plurality of concentrated water lines.

3. The water treatment device described in claim 2, wherein the at least one ultrafiltration membrane module is an internal pressure cross-flow type hollow fiber membrane module, and the concentrated water outlet of the hollow fiber membrane module is arranged so as to face upward, and the multiple concentrated water lines are each connected to the concentrated water outlet of the at least one ultrafiltration membrane module of the multiple ultrafiltration membrane devices.

4. A water treatment device as described in any one of claims 1 to 3, comprising: a blocking means provided in a connection line connecting a first ultrafiltration membrane device and a second ultrafiltration membrane device among the plurality of ultrafiltration membrane devices, blocking the flow of steam in the connection line; at least one discharge line connected to the connection line, discharging the blocked steam to the outside; and at least one temperature sensor provided in the at least one discharge line.

5. The water treatment device according to claim 4, further comprising a supply line through which permeated water from the first ultrafiltration membrane device flows and is supplied to the second ultrafiltration membrane device, and the connection line is the supply line.

6. The water treatment device according to claim 5, further comprising: a booster pump provided in the supply line; and a reflux line branching off from the concentrated water line of the second ultrafiltration membrane device and connected to the supply line upstream of the booster pump.

7. A water treatment device as described in claim 4, comprising: a supply line through which permeate from the first ultrafiltration membrane device is circulated and supplied to the second ultrafiltration membrane device; a booster pump provided on the supply line; and a return line branching off from the concentrated water line of the second ultrafiltration membrane device and connected to the supply line upstream of the booster pump, wherein the connecting line is the return line.

8. A water treatment device as described in claim 4, having two branch water supply lines that branch and supply the water to be treated to the first ultrafiltration membrane device and the second ultrafiltration membrane device, and the connection line is one of the two branch water supply lines.

9. A water treatment device as described in claim 4, having two branch water supply lines through which the permeated water from the first ultrafiltration membrane device and the permeated water from the second ultrafiltration membrane device flow and merge, and the connecting line is one of the two branch water supply lines.

10. A method for operating a water treatment device having a plurality of ultrafiltration membrane devices, each having at least one ultrafiltration membrane module, comprising the steps of introducing steam into the plurality of ultrafiltration membrane devices in parallel and sterilizing the plurality of ultrafiltration membrane devices with the steam.

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