CN109476509B

CN109476509B - Ultrapure water production apparatus

Info

Publication number: CN109476509B
Application number: CN201780046687.4A
Authority: CN
Inventors: 堀井重希
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2016-09-14
Filing date: 2017-03-16
Publication date: 2020-06-26
Anticipated expiration: 2037-03-16
Also published as: TW201811682A; TWI687374B; WO2018051552A1; CN109476509A; JP6149993B1; JP2018043191A; KR20190046717A; KR102107925B1

Abstract

Provided is an ultrapure water production apparatus which can reduce the cost of a heat source of a heat exchanger for heating ultrapure water to be sent to a point of use to produce warm ultrapure water, and can reduce the cost of cooling primary ultrapure water. The secondary pure water from the sub-system (4) is heated by the heat exchanger (6), the heat exchanger (10) and the heat exchanger (12) and sent to the point of use. The heat source of the heat exchanger (6) is warm ultrapure water returned from the point of use. The returned ultrapure water is cooled in the heat exchanger (6) and the heat exchanger (43), and then introduced into the sub-tank (2). A first medium water heated by a heat pump (20) is circulated through the heat exchanger (10). The evaporator 21 of the heat pump 20 is circulated with second medium water. A heat exchanger (26) for circulating warm drain water from a use point (40) is provided in the circulation path of the second medium water, and a heat exchanger (43) is provided on the upstream side of the heat exchanger (26).

Description

Ultrapure water production apparatus

Technical Field

The present invention relates to an ultrapure water production apparatus, and more particularly to an ultrapure water production apparatus which heats ultrapure water from a secondary ultrapure water production apparatus by a heat exchanger and supplies the ultrapure water to a point of use as warm ultrapure water.

Background

As shown in fig. 2, ultrapure water used as semiconductor cleaning water is produced by treating raw water (industrial water, domestic water, well water, etc.) with an ultrapure water production apparatus composed of a pretreatment system 50, a primary pure water production apparatus 60, and a secondary pure water production apparatus (often referred to as a sub-system) 70 (patent document 1). The functions of the systems in fig. 2 are as follows.

In the pretreatment system 50 including an aggregation device, a pressure flotation (sedimentation) device, a filtration (membrane filtration) device, and the like (in this conventional example, an aggregation and filtration device), suspended substances or colloidal substances in raw water are removed. In addition, in this process, high molecular organic substances, hydrophobic organic substances, and the like can be removed.

In a primary pure water production apparatus 60 provided with a tank 61 for pretreated water, a heat exchanger 65, a reverse osmosis membrane treatment apparatus (RO apparatus) 62, an ion exchange apparatus (mixed bed type, 4-bed 5-tower type, or the like) 63, a tank 63A, an ion exchange apparatus 63B, and a deaerator 64, ions and organic components in raw water are removed. Further, the higher the temperature of water, the lower the viscosity, and the higher the permeability of the RO membrane. Therefore, as shown in fig. 2, a heat exchanger 65 is provided at the front stage of the reverse osmosis membrane treatment apparatus 62, and the water is heated so that the temperature of the water supplied to the reverse osmosis membrane treatment apparatus 62 becomes equal to or higher than a predetermined temperature. Steam as a heat source fluid is supplied to the heat exchanger 65 on the 1 st side. In the reverse osmosis membrane treatment apparatus 62, ionic and colloidal TOC is removed by removing salts. In the

ion exchangers

63 and 63B, salts and Inorganic Carbon (IC) are removed, and the TOC component adsorbed or ion-exchanged is removed by an ion exchange resin. The Inorganic Carbon (IC) and dissolved oxygen are removed in the degasifier 64.

The primary deionized water produced by the primary deionized water production apparatus 60 is sent to the secondary deionized water production apparatus 70 via a pipe 69. The secondary pure water production apparatus 70 includes: an auxiliary tank (also referred to as a pure water tank) 71, a pump 72, a heat exchanger 73, a low-pressure ultraviolet oxidation apparatus (UV apparatus) 74, an ion exchange apparatus 75, and an ultrafiltration membrane (UF membrane) separation apparatus 76. The heat exchanger 73 is used for temperature control of the secondary pure water. Generally, the supply temperature of the secondary pure water (normal temperature ultrapure water) is 23 to 25 ℃, and a cooler is used in the heat exchanger 73 to control the temperature within this range. Cold water is used as a cooling source for the cooler. The heat exchanger 73 needs to be placed before the ion exchange unit 75. When high-temperature pure water comes into contact with the ion exchange resin, TOC components are eluted, and the water quality is deteriorated. Therefore, it is necessary to cool the water to 23 to 25 ℃ by the heat exchanger 73 and then send the water to the ion exchange device 75. When the cold water introduced into the cooling heat exchanger 73 is supplied from an electronic component manufacturing plant, a dedicated piping facility is required. In order to reduce the production cost of ultrapure water, it is desired to reduce the amount of cold water used.

Low pressure ultraviolet oxygenThe conversion unit 74 decomposes TOC into organic acids, even CO, by 185nm UV light from a low pressure UV lamp₂. Organic matter and CO produced by decomposition₂And removed in the ion exchange unit 75 in the latter stage. In the ultrafiltration membrane separation device 76, fine particles are removed, and particles flowing out from the ion exchange resin are also removed.

The treated water of the ion exchange device 75 is divided into: ultrapure water (normal temperature ultrapure water) sent from ultrafiltration membrane separation apparatus 76 to use point 90 via pipe 81, and ultrapure water (warm ultrapure water) heated by

heat exchangers

85 and 86 and sent to use point 90 via ultrafiltration membrane separation apparatus 87 and pipe 88.

The latter route heats the ultrapure water from the secondary pure water production apparatus 70 to about 65 to 75 ℃ by the first-stage side heat exchanger 85 and the second-stage side heat exchanger 86, and supplies the ultrapure water to the use point 90. The warm reflux water from the use point 90 is circulated to the heat source side of the front-stage side heat exchanger 85 via the pipe 91. The return water that has passed through the heat source side of the front-stage side heat exchanger 85 is cooled to about 30 to 40 ℃, and is returned to the sub-tank 71 via the pipe 92. The rear-stage side heat exchanger 86 uses steam as a heat source.

Patent document 1: japanese patent laid-open No. 2013-202581.

Disclosure of Invention

The invention aims to provide an ultrapure water manufacturing device which can reduce the cost of a heat source of a heat exchanger for heating ultrapure water to be sent to a using point to form warm ultrapure water and can reduce the cost for cooling primary ultrapure water.

An ultrapure water production apparatus according to an embodiment of the present invention, which supplies heated ultrapure water to a point of use, includes: a primary pure water production apparatus; a secondary pure water production device for producing ultrapure water by treating the primary pure water from the primary pure water production device; a first heat exchanger for heating the ultrapure water from the secondary pure water production apparatus and using the return water from the point of use as a heat source; a return water returning system including a second heat exchanger for cooling the return water having passed through the first heat exchanger, the return water cooled by the second heat exchanger being added to the primary pure water; and a heating mechanism for further heating the ultrapure water heated in the first heat exchanger; the heating mechanism is characterized by comprising: a third heat exchanger into whose heated fluid flow path the ultrapure water heated in the first heat exchanger is introduced; a first circulation flow path through which first medium water as a heat transfer medium circulates in the heat source fluid flow path of the third heat exchanger; and a heat pump for heating the first medium water flowing through the first circulation flow path; wherein: the heating pump is provided with a condenser, an evaporator, a pump and an expansion valve; the condenser is arranged on the first circulating flow path to heat the first medium water; the evaporator is arranged on a second circulating flow path in which second medium water circulates; the second circulation flow path is provided with a fourth heat exchanger for heating the second medium water by the heat of the warm drain water, and the second circulation flow path on the upstream side of the fourth heat exchanger is provided with the second heat exchanger.

In one embodiment of the present invention, the ultrapure water production apparatus is provided with a fifth heat exchanger for heating the ultrapure water heated in the third heat exchanger, and using steam as a heat source.

In one embodiment of the present invention, a sixth heat exchanger is provided in the first circulation flow path, the sixth heat exchanger being configured to heat the first medium water from the condenser to the third heat exchanger and to use steam as a heat source.

[ Effect of the invention ]

In the ultrapure water production apparatus of the present invention, the first heat exchanger heats ultrapure water by heat held by the use-point return water. The ultrapure water is further heated by a third heat exchanger using the first medium water heated by the condenser of the heat pump as a heat source fluid. The second medium water circulates in the evaporator of the heat pump. The second medium water is provided with: a fourth heat exchanger using warm waste water as a heat source, and a second heat exchanger using return water having passed through the first heat exchanger as a heat source. As a result, the heat source cost for heating the ultrapure water to be supplied to the point of use to a predetermined temperature to obtain a warm ultrapure water can be reduced. Further, since the return water having passed through the first heat exchanger is further cooled in the second heat exchanger and then added to the primary pure water, cold water for cooling the primary pure water can be eliminated or reduced.

The water temperature of the return water at the point of use is usually 70 to 80 ℃ such as about 75 ℃.

In the present invention, warm drain refers to drain used in washing at a point of use. The concentrated water of the UF membrane separation device provided immediately before the point of use may also be included in the warm drain water. The temperature of the warm discharge water is usually 60 to 75 ℃ such as about 65 ℃.

Drawings

FIG. 1 is a system diagram of an ultrapure water production system according to an embodiment.

FIG. 2 is a system diagram of an ultrapure water production system of the conventional example.

Detailed Description

The ultrapure water production apparatus of the present invention is provided with a primary pure water production apparatus, a secondary pure water production apparatus, and a heating mechanism for heating ultrapure water.

Usually, a pretreatment apparatus is provided in a stage preceding the primary pure water production apparatus. In the pretreatment apparatus, raw water is subjected to pretreatment by filtration, coagulation sedimentation, a microfiltration membrane, or the like, and suspended substances are mainly removed. Usually, the number of fine particles in water is 10 by this pretreatment³Less than one/mL.

A primary pure water production apparatus is provided with: and oxidation apparatuses such as Reverse Osmosis (RO) membrane separation apparatuses, degasification apparatuses, regenerative ion exchange apparatuses (mixed bed type, 4-bed 5-tower type, and the like), electrodeionization apparatuses, and Ultraviolet (UV) irradiation oxidation apparatuses, which remove most of electrolytes, fine particles, and bacteria in the pretreatment water. For example, the primary pure water production apparatus is composed of a heat exchanger, 2 or more RO membrane separation apparatuses, a mixed bed ion exchange apparatus, and a degasser.

The secondary pure water production apparatus is composed of a sub-tank, a water supply pump, a cooling heat exchanger, an ultraviolet irradiation apparatus such as a low-pressure ultraviolet oxidation apparatus or a sterilization apparatus, a non-regenerative mixed bed type ion exchange apparatus or an electrodeionization apparatus, a membrane filtration apparatus such as an Ultrafiltration (UF) membrane separation apparatus or a Microfiltration (MF) membrane separation apparatus, and may be further provided with a desalination apparatus such as a membrane degassing apparatus, an RO membrane separation apparatus, or an electrodeionization apparatus. In the secondary pure water production apparatus, TOC in water is oxidatively decomposed by ultraviolet rays using a low-pressure ultraviolet oxidation apparatus and a mixed bed type ion exchange apparatus is provided at the rear stage thereof, and oxidation decomposition products are removed by ion exchange. In the present specification, a portion of the secondary pure water production apparatus located on the rear stage side of the sub tank is hereinafter referred to as a sub system.

Further, a system may be adopted in which a third pure water production apparatus is provided at a later stage of the second pure water production apparatus and the ultrapure water from the third pure water production apparatus is heated. The tertiary pure water production apparatus has the same structure as the secondary pure water production apparatus, and produces ultrapure water of higher purity.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing an ultrapure water production system according to an embodiment. In the following description, water temperatures are given as examples, but the water temperatures are only examples and do not limit the present invention in any way.

The primary pure water of about 25 ℃ is introduced into the sub-system 4 through the pipe 1, the sub-tank 2, and the pipe 3, and ultrapure water is produced. The produced ultrapure water of about 25 ℃ is passed through the pipe 5, the heat exchanger 6, the pipe 7, the heat exchanger 10, the pipe 11, the vapor heat exchanger 12, the UF membrane separation apparatus 13, and the pipe 14 in this order, heated to about 75 ℃ by the

heat exchangers

6, 10, and 12, and sent to the use point 40 as warm ultrapure water through the pipe 14. The UF membrane separation device 13 is provided immediately before reaching the point of use 40.

The pipe 5 branches off from the pipe 5, and the normal temperature ultrapure water is sent to the point of use via the UF membrane separation device 5B and the pipe 5C.

The returned-temperature ultrapure water (returned water) from the use point 40 is introduced into the heat source fluid flow path of the heat exchanger 6 via the pipe 41. The returned ultrapure water having passed through the heat exchanger 6 is cooled by heat exchange with the second medium water of the heat pump 20 in the heat exchanger 43, and then sent to the sub-tank 2 through the pipe 44.

The first medium water (water as the heat transfer medium) heated by the condenser 23 of the heat pump 20 circulates through the heat source fluid flow path of the heat exchanger 10.

The heat pump 20 is constituted by: the heat medium such as a freon substitute from the evaporator 21 is compressed by the pump 22 and introduced into the condenser 23, and the heat medium from the condenser 23 is introduced into the evaporator 21 via the expansion valve 24.

The first medium water of about 75 ℃ from the heat exchanger 10 is introduced into the condenser 23 through the pipe 15, and the first medium water heated to about 80 ℃ in the condenser 23 is sent to the heat exchanger 10 through the pipe 16. Part of the first medium water from the condenser 23 is returned to the pipe 15 via the bypass pipe 17. The heat exchanger 10, the pipe 15, the condenser 23, and the pipe 16 constitute a first circulation flow path. The bypass pipe 17 is provided with a flow rate control valve (not shown).

A second circulation flow path formed by the pipe 25, the heat exchanger 43, the heat exchanger 26, and the pipe 27 is provided to circulate the second medium water through the heat source fluid flow path of the evaporator 21. Further, a bypass pipe 28 is provided between the

pipes

25 and 27. The bypass pipe 28 is provided with a flow rate control valve (not shown).

Warm drain water of about 65 ℃ at the use point 40 is introduced into the heat source fluid flow path of the heat exchanger 26 through the pipe 29. The warm drain water cooled to about 30 to 40 ℃ by heat exchange with the second medium flows out of the pipe 30 and is recovered as recovered water.

The second medium water heated to about 25 ℃ in the

heat exchangers

43 and 26 is introduced into the heat source fluid flow path of the evaporator 21, is cooled to about 20 ℃ by heat exchange with the heat medium of the heat pump 20, and is then sent to the heat exchanger 43 via the pipe 25. A part of the second medium water flows from the pipe 25 to the pipe 27 through the bypass pipe 28. The bypass pipe 28 is provided with a flow rate control valve (not shown).

In the second circulation flow path, the heat exchanger 43 is provided on the upstream side of the heat exchanger 26, that is, on the second medium water outlet side of the evaporator 21. The temperature of the return water (returned ultrapure water) having passed through the heat exchanger 6 (for example, about 32 ℃) is higher than the temperature of the second medium water (for example, about 20 ℃) which has been cooled in the evaporator 21 and flows into the pipe 25. Therefore, the return water from the heat exchanger 6 is cooled to almost the same temperature (about 23 to 25 ℃) as that of the normal-temperature ultrapure water in the heat exchanger 43, and then flows into the sub-tank 2.

As a result, a heat exchanger (the heat exchanger 73 in fig. 2) for cooling the primary pure water supplied from the sub-tank 2 to the sub-system 4 is not required. Further, even when the heat exchanger is provided, the amount of cold water used can be reduced.

As a method of operating the heat pump 20, for example, the input power of the heat pump compressor and the flow rate of the circulating water are adjusted so that the outlet temperatures of the first medium water and the second medium water become constant. The number of the heat pumps may be controlled in accordance with the heat load by a plurality of heat pumps. Further, as shown in the drawing, a pipe and a flow rate control valve for bypassing the heat exchanger may be provided in the circulation system on the high temperature side and/or the low temperature side to control the inlet temperature of the heat pump.

In fig. 1, only the warm drain water at the use point 40 is supplied to the heat exchanger 26, but the concentrated water provided in the UF membrane separation device 13 immediately before reaching the use point may be used as the warm drain water.

In the above embodiment, the vapor heat exchanger 12 is provided to heat ultrapure water heated in the heat exchanger 10, but may be provided in the first circulation flow path to heat the first medium water flowing from the condenser 23 to the heat exchanger 10. The vapor heat exchanger 12 or the vapor heat exchanger of the first circulation channel may be omitted. However, when the amount of the used warm ultrapure water in the factory is increased abruptly, it is estimated that the heat source of the heat pump 20 is insufficient and the temperature of the warm ultrapure water cannot reach the predetermined temperature. In order to prevent this, it is preferable to provide a steam heat exchanger so that steam heating can be performed as necessary.

The above embodiment is merely an example of the present invention, and the present invention may be other than the embodiment shown in the drawings.

While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes can be made therein without departing from the spirit and scope thereof.

The present application is based on Japanese patent application 2016-.

Claims

1. An ultrapure water production apparatus for supplying heated ultrapure water to a point of use, comprising:

a primary pure water production apparatus;

a secondary pure water production device for producing ultrapure water by treating the primary pure water from the primary pure water production device;

a first heat exchanger for heating the ultrapure water from the secondary pure water production apparatus and using the return water from the point of use as a heat source;

a return water returning system including a second heat exchanger for cooling the return water having passed through the first heat exchanger, the return water cooled by the second heat exchanger being added to the primary pure water; and

a heating mechanism for further heating the ultrapure water heated in the first heat exchanger;

it is characterized in that the preparation method is characterized in that,

the heating mechanism is provided with:

a third heat exchanger into whose heated fluid flow path the ultrapure water heated in the first heat exchanger is introduced;

a first circulation flow path through which first medium water as a heat transfer medium circulates in the heat source fluid flow path of the third heat exchanger; and

a heat pump that heats the first medium water flowing through the first circulation flow path;

wherein:

the heating pump is provided with a condenser, an evaporator, a pump and an expansion valve;

the condenser is arranged on the first circulating flow path to heat the first medium water;

the evaporator is arranged on a second circulating flow path in which second medium water circulates;

a fourth heat exchanger for heating the second medium water by using heat of warm discharge water is arranged on the second circulation flow path;

the second heat exchanger is provided in a second circulation flow path on the upstream side of the fourth heat exchanger.

2. The apparatus for producing ultrapure water as claimed in claim 1, wherein a fifth heat exchanger for heating the ultrapure water heated in the third heat exchanger and using a vapor as a heat source is provided.

3. The apparatus for producing ultrapure water according to claim 1 or 2, wherein a sixth heat exchanger for heating the first medium water from the condenser to the third heat exchanger and using steam as a heat source is provided in the first circulation flow path.