JP2023061693A - Operation method of pure water production system - Google Patents

Abstract

To provide an operation method of a pure water production system capable of producing pure water at a prescribed temperature in a method of producing pure water by a pure water production system equipped with a chiller system.SOLUTION: In an operation method of a pure water production system, raw water is RO treated by an RO device 6 to obtain permeated water (intermediate water). The intermediate water is cooled by a heat exchanger 11 through an intermediate tank 8. Then it is treated by an ion exchanger 13 to obtain pure water, and pure water at a prescribed temperature is discharged from a pure water tank 15 through a pipe 17. When the temperature of the pure water exceeds a prescribed temperature, a part of the pure water is returned to a raw water tank 1 and tap water is supplied to the intermediate tank 8.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method of operating a pure water production system, and more particularly to a method of operating a pure water production system having a chiller system to produce pure water at a predetermined temperature.

A system for producing pure water using waste water from a semiconductor manufacturing process or the like as raw water is used (Patent Document 1). This pure water production system includes an RO device for RO (reverse osmosis) treatment of raw water, an ion exchange device for ion exchange treatment of permeated water of the RO device, and the like.

JP 2019-177326 A

An object of the present invention is to provide a method of operating a pure water production system that is capable of producing pure water at a predetermined temperature in a method of producing pure water using a pure water production system equipped with a chiller system.

The gist of the operating method of the pure water production system of the present invention is as follows.

[1] A raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
and a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, comprising:
The pure water return means returns part of the pure water to the raw water tank when the temperature of the pure water taken out by the pure water tank or the pure water taking-out means rises above a specified temperature. How to operate a water production system.

[2] The method of operating the pure water production system of [1], wherein part of the pure water is returned to the raw water tank by the pure water return means, and industrial water is supplied to the intermediate tank.

[3] The operating method of the pure water production system of [2], wherein the operating conditions of the ion exchanger are adjusted in accordance with the supply of industrial water to the neutralization tank.

[4] The method of any one of [1] to [3] for supplying industrial water to the receiving means when the water temperature of the receiving means rises above a predetermined temperature due to the high-temperature waste water flowing into the receiving means. How to operate a water production system.

[5] A raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, and
A method of operating a pure water production system, wherein industrial water is supplied to said receiving means when the water temperature of said receiving means becomes higher than a predetermined temperature due to the high-temperature waste water flowing into said receiving means.

[6] A raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
and a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, comprising:
A method of operating a pure water production system, comprising supplying industrial water to the receiving means when the temperature of a medium circulating through the condenser of the heat pump and the second heat exchanger becomes higher than a predetermined temperature. .

[7] The method of operating a pure water production system according to any one of [4] to [6], wherein the industrial water supplied to the receiving means is well water.

[8] The receiving means has a neutralization tank, a storage tank into which water flows from the neutralization tank, and an outflow means for discharging water from the storage tank,
The method of operating a pure water production system according to any one of [4] to [7], wherein the concentrated water from the RO device and the high-temperature waste water are introduced into the neutralization tank.

[9] The method of operating a pure water production system according to [8], wherein the water in the reservoir is circulated through the second heat exchanger.

[10] The method of operating a pure water production system according to any one of [4] to [9], wherein the high-temperature waste water is boiler drain water.

According to the present invention, a raw water tank, an RO device for RO-treating water from the raw water tank, an intermediate tank for receiving permeated water of the RO device, and a first heat exchanger for exchanging heat with the intermediate water from the intermediate tank an ion exchange device through which intermediate water heat-exchanged by the first heat exchanger is passed; a pure water tank for receiving pure water that has passed through the ion exchange device; and pure water for taking out pure water from the pure water tank. a means for retrieving;
A pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank, a receiving means for receiving concentrated water from the RO device, and water from the receiving means circulating through In a pure water production system having a second heat exchanger that is cooled and a chiller system having a heat pump that transfers heat from the first heat exchanger to the second heat exchanger, the pure water supply is stopped. It is possible to produce pure water at a predetermined temperature.

1 is a configuration diagram of a pure water production system; FIG.

Embodiments will be described below with reference to the drawings.

Raw water (in this embodiment, factory waste water or its treated water, but not limited to this) is introduced into the raw water tank 1, sent to the membrane filtration device 4 via the pump 2 and the pipe 3, and then sent to the membrane filtration device. be done. As the membrane filtration device 4, an MF device is used in this embodiment, but it is not limited to the MF device as long as it can remove suspended solids and the like in the raw water. A filtering device may be employed.

Filtrated water filtered by the membrane filtration device 4 is sent from the pipe 5 to the RO device 6, and RO-treated water (permeated water) is sent to the intermediate tank 8 via the pipe 7 and stored therein.

The RO-treated water in the intermediate tank 8 is sent to the first heat exchanger 11 through the pump 9 and the pipe 10, heat exchanged to a predetermined temperature, and then sent to the ion exchange device 13 through the pipe 12. be done. The pure water produced by the ion exchange treatment in the ion exchange device 13 is introduced into the pure water tank 15 through the pipe 14 and stored therein. The pure water in the pure water tank 15 is taken out by the pump 16 and the piping 17 and sent to the pure water demand destination.

As the ion exchange device 13, devices having various configurations such as a two-bed three-tower type and a three-bed four-tower type can be used.

A pure water return pipe 18 branches off from the pipe 17 . The downstream side of the pipe 18 is branched into pipes 19 and 21, and pure water can be introduced into the intermediate tank 8 via the pipe 19 and the valve 20, and the raw water tank 1 via the pipe 21 and the valve 22. can be introduced into

Industrial water (industrial water, well water, tap water, etc.) can be introduced into the intermediate tank 8 via a pipe 23 and a valve 24 .

Brine (concentrated water) of the RO device 6 is introduced into the neutralization tank 40 through the pipe 30 . Industrial water (well water in this embodiment) can be introduced into the neutralization tank 40 through a pipe 31 and a valve 32 . The engineering water supplied through the pipe 23 and the engineering water supplied through the pipe 31 may be of the same type or of different types.

Boiler drain water, which is condensed water of steam, can be introduced into the neutralization tank 40 through a pipe 33 from a drain tank and a drain pump (not shown). Regenerated waste water from the ion exchange device 13 is introduced into the pre-neutralization tank 35 through the pipe 34 , neutralized in the pre-neutralization tank 35 , and then introduced into the neutralization tank 40 . Alternatively, the pre-neutralization tank 35 may be omitted, and the regeneration wastewater from the ion exchange device 13 may be directly introduced into the neutralization tank 40 through the pipe 34 .

Neutralized water neutralized by adding a neutralizing agent such as acid or alkali in the neutralization tank 40 is introduced into the storage tank 42 through the pipe 41 . The water in the storage tank 42 is introduced into the second heat exchanger 47 via the pump 45 and the pipe 46 , heat-exchanged in the heat exchanger 47 , and then returned to the storage tank 42 via the pipe 48 .

The water in the reservoir 42 is discharged through the pump 43 and the pipe 44 so that the water level in the reservoir 42 falls within a predetermined range.

The second heat exchanger 47 constitutes a part of a chiller system (heat pump-based heat transfer system) 49 for circulating low-temperature water to the first heat exchanger 11 . The water-cooled chiller 50 of the chiller system 49 compresses a heat medium such as alternative freon from the evaporator 51 with a compressor 52 and introduces it into the condenser 53, and evaporates the condensed heat medium from the condenser 53 through the expansion valve 54. A heat pump configured to introduce heat into vessel 51 .

The second medium water from the second heat exchanger 47 is introduced into the condenser 53 through the pipe 57, and the second medium water heated in the condenser 53 is supplied to the heat exchanger 47 through the pump 55 and the pipe 56. circulated.

On the other hand, the first medium water, which has been reduced in temperature by passing through the evaporator 51, is sent to the first heat exchanger 11 through the pipe 60, and heat exchanges with the water (intermediate water) from the storage tank 8. After the temperature rises, it is circulated to the evaporator 51 via the pump 61 and the pipe 62 .

In this embodiment, temperature sensors T17, T56, and T40 are provided in the pipes 17, 56 and the neutralization tank 40, but actually temperature sensors are also provided in other locations. The temperature sensor T<b>17 may be installed in the pure water tank 15 .

In the pure water production system configured in this way, during steady operation, as described above, raw water is subjected to RO treatment by the RO device 6 to become permeated water (intermediate water), and the intermediate water passes through the intermediate tank 8. After the temperature is lowered by the first heat exchanger 11 , the water is processed by the ion exchange device 13 to become pure water. Although the valves 20 and 22 are closed during normal operation, the valve 20 may be slightly opened to return a small amount of pure water to the intermediate tank 8 through the pipes 18 and 19 . The valves 24 and 32 are closed during normal operation.

Further, during steady operation, the brine of the RO device 6 is discharged from the neutralization tank 40 through the storage tank 42 to the outside of the system. The heat taken from the intermediate water in the first heat exchanger 11 passes through the chiller system 49 and is given (heat transferred) to the circulating water from the storage tank 42 in the second heat exchanger 47, and is in the form of hot water discharge. As a result, it is discharged from the pipe 44 to the outside of the system. In steady operation, the amount of heat transferred from the first heat exchanger 11 to the second heat exchanger 47 is sufficient, and the pure water temperature in the pure water tank 15 is maintained at normal temperature (for example, 23° C.±1° C.). be.

In this pure water production system, measures to be taken when the temperature of the pure water rises above the steady-state temperature due to various causes will be described below.

[When the pure water temperature rises due to a significant rise in raw water temperature or outside air temperature]
When the pure water temperature (the temperature detected by the temperature sensor T17) becomes higher than the first specified temperature (for example, 23.5° C.) due to a significant rise in raw water temperature or outside air temperature, the valve 22 is opened ( ), and part of the pure water is returned to the raw water tank 1 from the pipe 17. As a result, the amount of brine from the RO device 6 increases, the water temperature in the storage tank 42 decreases, the temperature of the water circulated from the storage tank 42 to the second heat exchanger 47 also decreases, and the first A sufficient amount of heat is transferred from the heat exchanger 11 to the second heat exchanger 47, the first heat exchanger 11 can sufficiently lower the temperature of the intermediate water, and the pure water temperature (temperature sensor T17 detects temperature) decreases.

In this way, when the pure water temperature does not decrease even if part of the pure water is returned, the amount of the pure water to be returned is increased. When the pure water temperature reaches a second specified temperature (for example, 24.0° C.) higher than the first specified temperature, the valve 24 is opened, industrial water such as well water is supplied to the intermediate tank 8, and the intermediate water is Lower the temperature. As a result, the pure water temperature (the temperature detected by the temperature sensor T17) is lowered.

Even when the pure water temperature does not rise, the valve 24 may be opened to supply industrial water to the intermediate tank 8 when the water level in the intermediate tank 8 falls below the specified water level.

Also, when the water level in the raw water tank 1 drops for some reason, the valve 24 may be opened to supply industrial water to the intermediate tank 8 .

Incidentally, the ion concentration of the industrial water is higher than that of the RO permeated water from the RO device 6 . Therefore, when operating by supplying industrial water to the intermediate tank 8, it is preferable to adjust the water flow condition of the ion exchange device 13 (the timing of regeneration of the ion exchange resin). It is preferable to introduce a program for automatically controlling the regeneration timing of the exchange resin.

[Case where temperature of pure water rises due to inflow of boiler drain water into neutralization tank 40]
Boiler drain water is hotter than RO brine. Therefore, when the drain pump is activated and the boiler drain water is introduced into the neutralization tank 40, the temperature of the inflow water from the intermediate tank 40 to the storage tank 42 rises. As a result, the temperature of the water stored in the storage tank 42 increases, the temperature of the water circulated from the storage tank 42 to the second heat exchanger 47 increases, and the temperature of the medium water flowing through the pipe 56 (the temperature detected by the temperature sensor T56) increases. As a result, the amount of heat transferred from the first heat exchanger 11 to the second heat exchanger 47 via the chiller system 49 is reduced, and the intermediate water is sufficiently cooled in the first heat exchanger 11. is not possible, and the temperature of the pure water produced may rise.

Therefore, when the boiler drain water flows into the neutralization tank 40 and the water temperature of the neutralization tank 40 (the temperature detected by the temperature sensor T40) rises above a predetermined temperature, the valve 32 is opened and the industrial water (this In the embodiment, well water) is introduced into the neutralization tank 40, and the temperature of the inflow water from the neutralization tank 40 to the storage tank 42 is set to normal temperature. As a result, a sufficient amount of heat is transferred from the first heat exchanger 11 to the second heat exchanger 47 via the chiller system 49, and the temperature of the intermediate water is sufficiently lowered in the first heat exchanger 11. Constant temperature pure water is produced.

[When the temperature of the medium water in the pipe 56 (the temperature detected by the temperature sensor T56) rises due to other causes]
The medium water temperature detected by the temperature sensor T56 may rise above the specified temperature for some reason other than the boiler drain water flowing into the neutralization tank 40 . Even in such a case, the valve 32 is opened, industrial water is introduced into the neutralization tank 40, and the temperature of the inflow water from the neutralization tank 40 to the storage tank 42 is brought to the normal temperature. As a result, a sufficient amount of heat is transferred from the first heat exchanger 11 to the second heat exchanger 47 via the chiller system 49, and the temperature of the intermediate water is sufficiently lowered in the first heat exchanger 11. Constant temperature pure water is produced.

In the above-described embodiment, when the supply of pure water to the pure water demander becomes temporarily unnecessary, the entire amount of pure water from the pipe 17 is returned to the raw water tank 1 . In this case, the quality of feed water to the RO device 6 is improved and the amount of RO brine is reduced.

The above-described embodiment is an example of the present invention, and the present invention may be in a form other than the above. For example, although the neutralization tank 40 receives boiler drain water in the above embodiment, it may receive high-temperature water other than boiler drain water.

1 Raw Water Tank 4 Membrane Filtration Device 6 RO Device 8 Intermediate Tank 11 First Heat Exchanger 13 Ion Exchanger 15 Pure Water Tank 40 Neutralization Tank 42 Storage Tank 47 Second Heat Exchanger 49 Chiller System 50 Water Cooling Chiller

Claims (10)

a raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
and a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, comprising:
When the temperature of the pure water taken out by the pure water tank or the pure water taking-out means rises above a specified temperature, the pure water return means returns part of the pure water to the raw water tank. How to operate a water production system. 2. A method of operating a pure water production system according to claim 1, wherein part of the pure water is returned to the raw water tank by said pure water return means, and industrial water is supplied to said intermediate tank. 3. A method of operating a pure water production system according to claim 2, wherein operating conditions of said ion exchange device are adjusted in accordance with supply of industrial water to said neutralization tank. The operation of the pure water production system according to any one of claims 1 to 3, wherein industrial water is supplied to the receiving means when the water temperature of the receiving means rises above a predetermined temperature due to the high-temperature wastewater flowing into the receiving means. Method. a raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
and a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, comprising:
A method of operating a pure water production system, wherein industrial water is supplied to said receiving means when the water temperature of said receiving means exceeds a predetermined temperature. a raw water tank;
an RO device for RO treating water from the raw water tank;
an intermediate tank for receiving permeated water (hereinafter referred to as intermediate water) of the RO device;
a first heat exchanger that exchanges heat with intermediate water from the intermediate tank;
an ion exchange device through which intermediate water heat-exchanged in the first heat exchanger is passed;
a pure water tank that receives pure water that has passed through the ion exchange device;
a pure water extracting means for extracting pure water from the pure water tank;
a pure water return means for returning part of the pure water taken out by the pure water take-out means to the raw water tank or the intermediate tank;
receiving means for receiving concentrated water from the RO device;
a second heat exchanger through which water from the receiving means is circulated;
and a chiller system having a heat pump for transferring heat from the first heat exchanger to the second heat exchanger, comprising:
A method of operating a pure water production system, comprising supplying industrial water to the receiving means when the temperature of a medium circulating through the condenser of the heat pump and the second heat exchanger becomes higher than a predetermined temperature. . The operating method of a pure water production system according to any one of claims 4 to 6, wherein the industrial water supplied to said receiving means is well water. The receiving means has a neutralization tank, a storage tank into which water flows from the neutralization tank, and an outflow means for discharging water from the storage tank,
The method of operating a pure water production system according to any one of claims 4 to 7, wherein the concentrated water and the high-temperature waste water from the RO device are introduced into the neutralization tank. 9. The method of operating a pure water production system according to claim 8, wherein the water in the storage tank is circulated through the second heat exchanger. The method of operating a pure water production system according to any one of claims 4 to 9, wherein said high-temperature waste water is boiler drain water.

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