JPH11216329A - Demineralized water manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a demineralized water manufacturing device which is simplified and especially suitable for use in manufacture of semiconductors. SOLUTION: A humidifier 52 which humidifies a gas by bringing warm water in contact with gas, a solid polymer electrolyte module 51 constituted by laminating a plurality of solid polymer electrolytic elements wherein an electrode is provided on both sides of a hydrogen ion electroconductive solid polymer electrolyte film while a vent path is formed, and a water condenser 55 condensing steam by cooling the gas humidified in a saturated state are provided. The humidifier 52 is connected to an anode side vent path 54 of the solid polymer electrolyte module 51 via a gas circulation means 57, and the gas becomes capable of being circulated. Further, the water condenser 55 is connected to a cathode side vent path 56 of the solid polymer electrolyte module 51 via a gas circulation means 58, and the gas becomes capable of being circulated between both.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing pure water by the electrolytic action of electrolyzing water vapor in air using a hydrogen ion conductive solid polymer electrolytic module.

[0002]

2. Description of the Related Art FIG. 6 is a diagram for explaining a conventional typical ultrapure water production system. This shows what is described in "Basic knowledge of new water" (by Shoji Kubota, published by Ohmsha). In FIG. 6, the apparatus is roughly divided into four parts: a pretreatment system 1, a pure water system 2, an ultrapure water system 3, and a wastewater recovery system 4. The pretreatment system 1 includes a coagulation tank 5 and a filter 6, and coagulates and precipitates and filters turbid and colloidal substances in raw water. Next, the treated water is treated by a reverse osmosis (RO) device 7 to remove dissolved and dispersed salts, organic substances, fine particles, viable bacteria and the like. The reason for removing the turbidity component prior to the RO treatment 7 is that if the turbidity component is contained in the treated water, it may cause clogging of the RO membrane and the like, which not only makes the maintenance of the apparatus troublesome, but also reduces the water quality. It is also a cause. RO
The carbon dioxide, dissolved oxygen, and the like that have not been removed in step (a) are removed in the deaerator 8.

[0003] Further, trace amounts of ions remaining in the permeated water are desalted in an ion exchange device 9 to become high-purity pure water.
It is sent to the ultrapure water system 3. In ultrapure water system 3,
In order to make the primary purified water into pure water of higher purity, the ultraviolet sterilizer 10 sterilizes and removes residual ions and fine particles. The ultraviolet sterilizer uses ultraviolet light having a wavelength of about 254 nm.
The deminer 11 is a non-regeneration type ion exchange resin tower.

[0004] The ultrafiltration device or reverse osmosis device 12 is also called a final filter, and plays a role of finishing the ultrapure water. Here, a very small amount of the crushed product of the ion exchange resin, bacteria, fine particles and the like are removed, and the water is converted into highly purified water and supplied to the use point 13. The generated ultrapure water is constantly circulated and purified. Wastewater from the use point 13 with relatively little contamination is removed of organic matter by the activated carbon tower 14 and ions by the ion-exchange tree device 15, and a trace amount of organic matter is oxidatively decomposed by the ultraviolet oxidizer 16 and then sent to the pretreatment system 1. Return and reuse.

[0005]

The conventional ultrapure water production apparatus is configured as described above, and the system is constituted by a great number of components for removing solid components, removing dissolved gas components, removing ions, and the like. I needed to. In addition, since various kinds of filters for filtration are required to remove salts, organic substances, fine particles, viable bacteria and the like from the outside, maintenance is required. An object of the present invention is to solve the conventional problems as described above and to electrochemically separate a pure water system from a makeup water system,
It is an object of the present invention to provide a simplified pure water production apparatus particularly suitable for semiconductor production.

[0006]

SUMMARY OF THE INVENTION The present invention provides a humidifier for humidifying a gas by bringing hot water into contact with a gas, and a plurality of solid polymers provided with electrodes on both surfaces of a hydrogen ion conductive solid polymer electrolyte membrane. A solid polymer electrolytic module configured by laminating electrolytic elements while forming an air passage, and a water condenser for cooling a gas humidified to a saturated state and condensing water vapor, the humidifier and the The anode side ventilation path of the solid polymer electrolysis module is connected via gas circulation means so that gas can be circulated between them, and the water condenser and the cathode side ventilation path of the solid polymer electrolysis module are connected to each other. Are connected via gas circulation means so that gas can be circulated between the two.

Further, according to the present invention, cold water is passed through a cooler provided in a water condenser, which is used for condensing water vapor by cooling a gas humidified to a saturated state, thereby recovering heat of condensation. The hot water is supplied to a humidifier, and the hot water is fed into the humidifier. The circulating gas is humidified by directly contacting the gas circulating in the humidifier.

Further, according to the present invention, oxygen generated on the anode side by the electrolytic action of the solid polymer electrolytic module is introduced into the cathode side ventilation passage of the solid polymer electrolytic module and consumed on the cathode side of the solid polymer electrolytic module. An object of the present invention is to provide the pure water producing apparatus described above, which replenishes oxygen.

Further, according to the present invention, the gas circulating in the cathode side ventilation passage of the solid polymer electrolysis module is hydrogen gas generated on the cathode side of the solid polymer electrolysis module, A part of the cathode side ventilation path is connected to the catalyst layer, and oxygen generated on the anode side of the solid polymer electrolyte module and hydrogen generated on the cathode side are sent into the catalyst layer for reaction treatment. The pure water producing apparatus described above is provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a system configuration diagram of an ultrapure water production apparatus 50 of the present invention. In FIG. 1, reference numeral 51 denotes a solid polymer electrolysis module (hereinafter, referred to as an electrolysis module), which has a function of electrochemically moving water vapor in a primary air stream to a secondary side, the details of which will be described later. Reference numeral 52 denotes a humidifier,
The circulating gas is humidified by making direct contact with the circulating gas circulating in the anode side ventilation passage 54 of the electrolytic module 3.
Reference numeral 55 denotes a water condenser, which cools the saturated circulating gas circulating in the cathode side ventilation path 56 of the electrolytic module to condense and drop water vapor. In the anode side ventilation path 54 and the cathode side ventilation path 56, gas circulation means 57 and 58 (for example, a blower) for circulating gas are arranged, respectively, and circulate the gas in the respective ventilation paths. Humidifier 5
A circulating water pump 59 is connected to 2, and the water collected at the bottom of the humidifier 52 is pumped up to the top to be dropped and brought into direct contact with the circulating gas circulating through the anode side ventilation path 54. An intake pipe 60 is connected to the bottom of the water condenser 55, and condensed water 61 is provided.
So that you can take water.

FIG. 2 is a view for explaining a solid polymer electrolytic element 62 (hereinafter referred to as an electrolytic element) constituting the electrolytic module 50 used in the present invention. In FIG. 2, 63
a and b are porous electrodes, for example, made of expanded metal or the like. The pair of porous electrodes 63 a and 63 b are provided, for example, by thermal pressure contact on both surfaces of the proton conductive solid polymer electrolyte membrane 64. Porous electrodes 63a, 6
Electric contact pieces 65a and 65b are attached to both ends of 3b so that electricity from a power supply system is supplied to the electrodes. Porous electrodes 63a and 63b and solid polymer electrolyte membrane 6
Although not shown, a platinum group metal catalyst layer is formed on the bonding surface of No. 4 or the outer surface of the electrode to increase the activity of the electrolytic reaction on both electrode surfaces.

FIG. 3 is a diagram for explaining an electrolysis module 51 used in the present invention. In FIG.
Is an electrolytic element shown in FIG. Reference numeral 66 denotes a spacer for stacking the electrolytic elements 62 at a constant interval and forming an air passage 67. Spacers 66 are alternately arranged at both ends of the electrolytic element 62 so that adjacent air flow paths 67 are orthogonal to each other. In some cases, a second spacer 68 is provided to stack the electrolytic elements 62 at a constant interval. The spacer 66 is formed by attaching a conductive metal plate to the surface of an electrically good conductor such as a carbon rod or an insulating block of plastic or the like. When the electrolytic element 62 is stacked via the spacer 66, the upper and lower elements 62 The space can be electrically connected.

Next, the operation of the electrolysis module 51 will be described. As shown in FIG. 2, the electrolytic element 62 constituting the electrolytic module 51 sandwiches a solid polymer electrolyte membrane 64 that selectively allows hydrogen ions (protons) to pass therethrough. , 63b are provided, for example, by hot pressing to form a composite film. As the solid polymer electrolyte membrane 64, for example, a Nafion (registered trademark of DuPont) membrane or the like is used. The electrodes 63a and 63b are made of expanded titanium plated with platinum, and the cathode 63b is made of a nonwoven fabric of carbon fiber. The DC power supply 69 is connected to the electrolytic element 62 such that the dehumidified side is on the anode side and the humidified side is on the cathode side. Then, when power is supplied between the anode 63a and the cathode 63b from the DC power supply 69, water vapor in the air on the anode side is electrolyzed, and water molecules are decomposed by the reaction of the following formula (1) to generate oxygen. And the humidity decreases.

[0014] _{anode: 2H 2 O → O 2 +} 4H + + 4e - (1)

Further, a plurality of water molecules move from the anode side to the cathode side accompanying the hydrogen ions. Accordingly, since water molecules are consumed on the anode side, the humidity is reduced and dry air is obtained. Hydrogen ions (H ⁺ ) generated on the anode side during the electrolytic reaction pass through the solid polymer electrolyte membrane 64 and reach the cathode. On the other hand, the electrons (e ⁻ ) reach the cathode through an external circuit. Then, oxygen is consumed on the cathode side by the reaction of the following formula (2) to generate water.

Cathode side: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)

As a result, the air flowing on the cathode side is humidified and becomes humid air. With the above operation, the module 51
The air flow indicated by the arrow A flowing through the air passage 67a opposed to the anode is dehumidified and becomes a dry air body because the water vapor contained in the air is electrolyzed and consumed. On the other hand, the air flow indicated by the arrow B flowing through the ventilation passage 67b facing the cathode is humidified because the oxygen is consumed to generate water vapor, and becomes a humid air flow. Further, the air flows indicated by arrows A and B are formed by cross flow, and the respective air flows are taken out from different directions. The power required for the electrolytic reaction represented by the above equations (1) and (2) is supplied from the DC power supply 69.

Next, the operation of the system shown in FIG. 1 will be described. Gas circulation means 57 such as a blower is provided in the humidifier 52 and the ventilation passage 54 on the anode side of the electrolytic module 51, thereby circulating the gas in the ventilation passage 54. At this time, when the gas passes through the anode surface of the electrolytic module 51, the water vapor in the gas is consumed by the electrolytic reaction shown in the above formula (1), is dried and discharged, and is sent to the bottom of the humidifier 52. The gas sent to the bottom of the humidifier 52 is humidified by coming into direct contact with the hot water 53 dropped from the top, sent again to the anode side of the electrolytic module 51, and repeats circulation. The hot water 53 dropped from the top of the humidifier partially evaporates and humidifies the gas when it comes into direct contact with the low-humidity gas sent to the bottom of the humidifier 52. After being stored at the bottom of the humidifier 52, it is sent to a water heater 70 by a circulation pump 59, where the water is heated and the humidifier 52
The circulation sent to the top of the is repeated. The circulating gas circulates oxygen gas generated on the anode side or circulates by partially taking in outside air.

Next, the water condenser 55 and the electrolysis module 51
A gas circulating means 58 such as a blower is provided in the ventilation path 56 on the cathode side of the above, whereby the gas in the ventilation path 56 is circulated. At this time, the gas passes through the cathode surface of the electrolytic module 51, and the circulating gas is humidified and saturated by consuming oxygen in the gas stream and generating water vapor by the electrolytic reaction shown in the above formula (2). In the course of cooling, the gas sent to the water condenser 55 is condensed with water vapor in the gas to be separated as condensed water 61, and the gas repeats the circulation sent to the cathode side of the electrolytic module 51 again. The condensed water 61 is taken out of the water intake pipe 60 as pure water and used.

Since oxygen in the gas circulating in the water condenser 55 and the cathode side ventilation passage 56 of the electrolysis module 51 is consumed as shown in the above equation (2), it is necessary to supply a reduced amount of oxygen. . Therefore, the anode side ventilation path 54 and the cathode side ventilation path 5
1 are connected by a branch circuit 71 as shown in FIG. 1 so that oxygen generated on the anode side is supplied to the cathode side ventilation path 56 or is circulated by partially taking in outside air.

Embodiment 2 FIG. Embodiment 1 FIG. In the humidifier, warm water 53 is dropped from the top of the humidifier to humidify the gas sent to the bottom of the humidifier 52, and humidified by direct contact. The water stored at the bottom of the humidifier 52 is water after contacting with low-humidity air, so the latent heat of evaporation is deprived and the temperature is lowered. Therefore, the water is heated by the water heater 70 and sent to the top of the humidifier 52.
As shown in the figure, the function of the water heater 70 is also used by the water condenser 55, and the circulation pump 5 is provided to the cooler 55a constituting the water condenser.
At 9, the water stored in the bottom of the humidifier 52 may be sent to recover the heat of condensation from the gas humidified to a saturated state in the water condenser to make it hot water.

Embodiment 3 FIG. Embodiment 1 FIG. And 2.
In order to supply oxygen consumed on the cathode side of the electrolytic module 51, oxygen generated on the anode side is supplied to the cathode side,
Alternatively, it circulates by taking in some outside air. In this case, since the process of cooling the saturated gas to obtain condensed water is performed in an aerobic state, oxygen slightly dissolves in the condensed water. Although a large amount of ultrapure water is used in a semiconductor production line, it is often required that there is no dissolved oxygen in the ultrapure water. In this case, as shown in FIG. 5, hydrogen generated by a chemical reaction represented by the following formula (3) is adopted as a gas circulating in the cathode side ventilation passage 56, and oxygen-free pure water is circulated to circulate the hydrogen. Can be obtained.

Cathode side: 2H ⁺ + 2e ⁻ → H ₂ (3)

In the above formula (3), no water is generated, but when hydrogen ions (H ⁺ ) move from the anode side to the cathode side,
A plurality of water molecules (about three molecules) move together and humidify the gas circulating on the cathode side. By cooling this humidified gas, the entrained water molecules are condensed in an oxygen-free environment,
It can be taken out as condensed water without dissolved oxygen. In this case, since oxygen is continuously generated from the anode side and hydrogen is continuously generated from the cathode side, surplus gas is taken out from each of the branch passages 72 and sent to a catalyst layer 73 made of, for example, a platinum-based metal for reaction treatment.

[0025]

According to the first aspect of the invention, a humidifier for humidifying a gas by bringing hot water into contact with a gas, and a plurality of solids having electrodes provided on both surfaces of a hydrogen ion conductive solid polymer electrolyte membrane. A humidifier comprising: a solid polymer electrolytic module configured by stacking polymer electrolytic elements while forming an air ventilation path; and a water condenser for cooling a gas humidified to a saturated state and condensing water vapor. And the anode-side ventilation path of the solid polymer electrolyte module are connected via gas circulation means so that gas can be circulated therebetween, and the water condenser and the cathode-side ventilation of the polymer electrolyte module are connected. Since the path is connected to the path via the gas circulating means and the gas can be circulated between the two, a simplified pure water production apparatus with few components can be obtained.

According to the second aspect of the present invention, cold water is passed through a cooler provided in the water condenser, which is used for cooling the humidified gas to a saturated state and condensing water vapor.
Collect the heat of condensation to make it hot water, send it to the humidifier,
Since the circulating gas is humidified by being brought into direct contact with the gas circulating in the humidifier, an energy-saving pure water producing apparatus can be obtained.

According to the third aspect of the present invention, oxygen generated on the anode side by the electrolytic action of the polymer electrolyte module is
Introduced into the cathode side ventilation path of the polymer electrolyte module to supply oxygen consumed on the cathode side of the polymer electrolyte module, so there is no need to take in outside air, and external contamination in a closed space. An ultrapure water production apparatus that produces pure water without being affected by the above is obtained.

According to the fourth aspect of the present invention, the gas circulating in the cathode side ventilation path of the solid polymer electrolytic module is hydrogen gas generated on the cathode side of the solid polymer electrolytic module,
A part of the anode-side ventilation path and the cathode-side ventilation path of the solid polymer electrolysis module are connected to a catalyst layer, and oxygen generated on the anode side of the solid polymer electrolysis module and hydrogen generated on the cathode side are converted into the catalyst. In order to send it into the layer for reaction processing,
An ultrapure water production device that produces pure water without dissolved oxygen is obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a pure water production apparatus of the present invention.

FIG. 2 is a diagram illustrating a solid polymer electrolyte device used in the present invention.

FIG. 3 is a diagram illustrating a solid polymer electrolytic module used in the present invention.

FIG. 4 is another system configuration diagram of the pure water production apparatus of the present invention.

FIG. 5 is still another system configuration diagram of the pure water production apparatus of the present invention.

FIG. 6 is a system configuration diagram of a conventional pure water production apparatus.

[Explanation of symbols]

1 Pretreatment system, 3 Ultrapure water system, 4 Wastewater recovery system, 5 Coagulation tank, 6 Filter, 7 Reverse osmosis (R
O) device, 8 degassing tower, 9 ion exchange device, 10 ultraviolet sterilizer, 11 deminer, 12 ultrafiltration device or reverse osmosis device, 13 use point, 14 activated carbon tower, 15 ion exchange tree device, 50 pure water production Equipment, 5
1 electrolysis module, 52 humidifier, 54 anode side ventilation path, 55 water condenser, 56 cathode side ventilation path, 57, 58
Gas circulation means, 59 circulating water pump, 60 intake pipe,
61 condensed water, 62 solid polymer electrolyte element, 66 spacer, 70 water heater, 71 branch circuit.

Claims (4)

[Claims] 1. A humidifier for humidifying a gas by bringing hot water and a gas into contact with each other, and a plurality of solid polymer electrolyte elements provided with electrodes on both surfaces of a hydrogen ion conductive solid polymer electrolyte membrane through an air passage. A solid polymer electrolysis module formed by stacking while forming, and a water condenser for cooling gas humidified to a saturated state and condensing water vapor, wherein the humidifier and the anode side of the solid polymer electrolysis module An air passage is connected via gas circulation means so that gas can be circulated therebetween, and the water condenser and the cathode air passage of the polymer electrolyte module are connected via gas circulation means. And a gas circulator between the two. 2. Cooling water is passed through a cooler provided in a water condenser, which is used for condensing water vapor by cooling a gas humidified to a saturated state, and recovering heat of condensation to make hot water. ,
2. The pure water production apparatus according to claim 1, wherein the circulating gas is fed into a humidifier and brought into direct contact with a gas circulating in the humidifier to humidify the circulating gas. 3. The oxygen generated on the anode side by the electrolytic action of the solid polymer electrolysis module is introduced into the cathode side ventilation path of the solid polymer electrolysis module to supply oxygen consumed on the cathode side of the solid polymer electrolysis module. The pure water production apparatus according to claim 1 or 2, wherein 4. The gas circulating in the cathode side ventilation passage of the solid polymer electrolysis module is hydrogen gas generated on the cathode side of the solid polymer electrolysis module, and the anode side ventilation passage and the cathode side ventilation passage of the solid polymer electrolysis module are used. Is connected to the catalyst layer, and oxygen generated on the anode side of the solid polymer electrolyte module and hydrogen generated on the cathode side are sent into the catalyst layer for reaction treatment. 1 or 2
2. The pure water production apparatus according to 1.