JPH0557300A - Extra pure water producing apparatus - Google Patents

Abstract

PURPOSE:To provide an extra pure water producing apparatus for drastically reducing an organic component and being excellent in energy efficiency. CONSTITUTION:In this apparatus, a degassing part 101, a film distillation parts 102 and 103, a condensating part 104, an organic material removing part 105 and a heat exchanger 106 are provided, and an organic material in an original water, before the degassing and the film distillation, is decomposed at the organic material removing part 105. As a heat source, waster heat of a generating set is used. Thus, an extrapure water containing only a minute organic compd. content can be obtained. And, as waste heat from the generating set is able to be utilized for latent heat being necessary in the phase conversion, a highly efficient usage of energy is available and so, an inexpensive production of extrapure water having high purity becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrapure water production system used for cleaning semiconductors (LSI), disks and other electronic parts, and more particularly to an ultrapure water production system in which organic impurities (TOC components) are extremely small. Regarding

[0002]

2. Description of the Related Art Conventionally, ultrapure water used for cleaning semiconductors, etc. has been manufactured by using a reverse osmosis membrane, an ion exchange resin, an ultraviolet oxidation / sterilization lamp
Although it has been produced by a device such as an ultrafiltration membrane, the inventors of the present invention, as disclosed in JP-A-63-305917, from the need that impurities do not remain on the object to be cleaned after cleaning and drying, A method for producing ultrapure water was devised in which high-purity water is obtained by evaporating raw water and filtering the generated water vapor with a hydrophobic porous membrane to remove mist accompanied by water vapor and then condensing it. FIG. 3 shows the principle of this method. This apparatus comprises a degassing section 301 and a membrane distillation section 302. The raw water 303 is first sent to the degassing section 301 and is heated and degassed. In the degassing section 301, volatile components contained in the raw water, such as oxygen, carbon dioxide, and volatile organic substances, are removed together with water vapor. The raw water from which the volatile components have been removed is then sent to the membrane distillation unit 302 and heated again. Here, only water vapor and mist are present in the gas phase. Furthermore, by filtering this water vapor with the hydrophobic porous membrane 304, the mist accompanying the water vapor is completely removed. In this way, high-purity steam is obtained, and by condensing this steam on the condensing surface 305, the ultrapure water 3
06 can be generated. FIG. 4 further shows a system of a multi-use device for reducing the cost of water production. This apparatus also comprises a degassing section 401 and a membrane distillation section 402, and in this case, the membrane distillation section has a triple effect. The raw water 403 is sent to the deaerator 401 after recovering the condensation heat of the steam generated from the final stage. The water vapor generated in the degassing section 401 is sent to the condenser section 404 in the first stage of the membrane distillation section and condensed. Here, the generated heat of condensation is used for evaporation of raw water in the first stage of the membrane distillation section, and steam is generated from the first stage. By repeating this operation in sequence and finally condensing the steam generated from the third stage of the membrane distillation section in the condenser 405, the generated water can be obtained three times with one heat input. .. The ultrapure water generated from each stage is collected and obtained from the ultrapure water outlet 406.

[0003]

Conventionally, the water quality of ultrapure water has been evaluated by items such as resistivity, fine particles, viable bacteria, TOC, silica, DO, etc., but each evaluation item is from ppb to ppt level. It has been reduced to the concentration, and it is in a situation where the superiority difference cannot be seen. Among them, TOC (total organic carbon) has the largest amount of impurities, and even the currently highest grade ultrapure water contains ppb level impurities. In the conventional method, since there is no means for removing the organic components in the raw water, there is a problem that the volatile organic substances contained in the raw water are diffused into the produced water and are dissolved again to be mixed. Also,
Since this method involves a phase change (distillation operation), a large amount of heat is required as energy. Therefore, conventionally, the energy is reduced by achieving the multiple utility as shown in FIG. 4. As described above, the conventional technique has two problems of TOC and reduction of thermal energy.

[0004]

[Means for Solving the Problems] TOC among these problems
The problem relating to the above can be solved by previously removing the TOC component in the raw water in the preceding stage, that is, by providing the raw water supply line with an oxidizing device for TOC by ultraviolet rays or an oxidizing device by heating. Further, in reducing heat energy, waste heat utilization is effective, and in particular, heat for producing ultrapure water from exhaust gas of a gas turbine or a diesel engine can be obtained.

[0005]

The TOC component in the raw water is decomposed in advance, and then the distillation operation is performed to treat the raw water having a small TOC component, so that the produced water having a small TOC component can be obtained. In addition, by using the exhaust heat of the gas turbine or diesel engine used for private power generation as the heat used for distillation, it is possible to supply power to a factory that uses ultrapure water, such as a semiconductor factory or a disk factory, at the same time. Pure water can be supplied, and energy can be used with high efficiency.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIGS.

FIG. 1 shows a system diagram of the ultrapure water production system of the present invention. This apparatus comprises a degassing section 101, a membrane distillation section 102, 10
3, condensation section 104, organic matter removal section 105, heat exchange section 10
6 is included, and in this embodiment, the membrane distillation section has a double effect. The raw water 107 collects the heat of condensation of the steam generated from the final stage as cooling water for the condenser, and then the heat exchanger 106.
And is heated by the organic matter removing unit 105,
Organic matter contained in raw water is decomposed under high pressure environment.
Here, in the organic substance removing section 105, the temperature is 200 ° C. or higher and the pressure is 15.9 atm or higher. It should be noted that an oxidizing agent such as hydrogen peroxide or potassium persulfate is previously mixed into the raw water from the chemical liquid injecting unit 108 so that the organic matter is easily oxidized under this condition. The high temperature raw water in which the organic matter is decomposed in the organic matter removing unit 105 exchanges heat with the raw water in the organic matter removing unit 105 in the heat exchange unit 106 to lower the temperature, and then is sent to the degassing unit 101. The raw water supplied to the heat exchange unit 109 in the degassing unit 101 heats the raw water in the degassing unit 101 to generate steam 110, and then the degassing unit 10
It is supplied as raw water of 1. Here, only the outlet water from the heat exchange section 106 is entered as the heat supply source in the degassing section 101, but it is also possible to install another heating source in the degassing section 101. Water vapor 1 generated in the deaerator 101
10 is sent to the heat exchange section 111 of the membrane distillation section 102 and serves as a heat source for raw water. Raw water 11 deaerated in the deaeration unit 101
2 is sent to the raw water side of the membrane distillation unit 102. Membrane distillation section 1
In 02, the distillation operation is performed again. Membrane distillation unit 102
Then, since the volatile components in the raw water have been removed by the degassing unit 101, the impurities contained in the water vapor are only mist (fine water droplets). By removing this mist with the hydrophobic porous film 113, it is possible to produce high-purity water vapor 114. This steam is condensed in the heat exchange section 115 of the membrane distillation section 103 and taken out of the system as ultrapure water. Utilizing the heat of condensation of the steam, the raw water is evaporated again in the membrane distillation unit 103, and the generated steam causes the generated steam to condense.
At 4, the raw water 107 is condensed to obtain ultrapure water 116. Here, in the conventional method, the membrane distillation units 102, 1
In 03, it was not possible to remove volatile organic substances in raw water,
Although organic substances were often mixed in the generated ultrapure water, the amount of organic substances (TOC) in the generated ultrapure water can be significantly reduced by decomposing the organic component in the raw water in the previous stage. .. In this example, the organic substance decomposition method is a heating method, and the example in which the membrane distillation section has a double effect was shown.
There is no problem with decomposition by UV, triple or quadruple effects.

FIG. 2 shows an example of heat supply means of the ultrapure water system according to the present invention. This example comprises a gas turbine section 201, an exhaust heat recovery section 202, and an ultrapure water production system 203 by a distillation method. The air 204 is pressurized by the compression unit 205 and sent to the combustion unit 206. In the combustion unit 206, the fuel 207 is combusted by the compressed air 208, and the combustion gas 2
The turbine 210 is rotated by 09. Turbine 21
The generator 211 is connected to 0, and converts the rotational energy of the turbine 210 into electricity. Exhaust gas 212 discharged from the turbine 210 is sent to the exhaust heat recovery unit 202 and recovers thermal energy by generating steam or the like from the raw water 213. The recovered thermal energy 214 is used as a heat source for the distillation type ultrapure water producing apparatus 203. Although a gas turbine is used in this embodiment, a diesel engine or the like may be used, and the exhaust gas may be sent to the ultrapure water device as it is without providing an exhaust heat recovery unit.

[0009]

According to the present invention, ultrapure water with a small amount of organic matter (TOC) can be obtained, and the latent heat required for phase change can be utilized by using the exhaust heat from the power generating equipment to achieve high energy efficiency. Therefore, ultrapure water of high purity and inexpensive can be produced.

[Brief description of drawings]

FIG. 1 is a system diagram of an ultrapure water production system according to the present invention.

FIG. 2 is a system diagram showing an example of heat supply means of the ultrapure water system according to the present invention.

FIG. 3 is a block diagram showing the principle of a conventional ultrapure water production system.

FIG. 4 is a system diagram of a conventional ultrapure water production system.

[Explanation of symbols]

101 ... Deaeration section, 102, 103 ... Membrane distillation section, 104 ...
Condensing part, 105 ... Organic matter removing part, 106 ... Heat exchange part, 1
13 ... Hydrophobic porous membrane.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C02F 1/20 A 9262-4D // C02F 1/72 Z 9045-4D

Claims (5)

[Claims] 1. An ultrapure water production apparatus for obtaining high-purity water by evaporating raw water and filtering generated steam with a hydrophobic porous membrane to remove mist accompanied by steam and then condensing the mist. 2. An ultrapure water production system, characterized in that the raw water system before evaporation is provided with means for removing organic matter in the water. 2. The ultrapure water production according to claim 1, wherein a heating device is used as the organic substance removing means, and heat is exchanged between the raw water that has exited from the heating device and the raw water that has not entered the heating device. apparatus. 3. The apparatus for producing ultrapure water according to claim 1, wherein a heating device is used as the organic substance removing means, and the raw water is evaporated by the heat of the raw water heated by the heating device. 4. An ultrapure water producing apparatus for obtaining high-purity water by evaporating raw water and filtering generated steam with a hydrophobic porous membrane to remove mist accompanied by steam and then condensing the mist. 3. An ultrapure water production system using residual heat of exhaust gas from a power generator as a heat source used for evaporation of the raw water. 5. The apparatus for producing ultrapure water according to claim 4, wherein the raw water system before evaporation is provided with a means for removing organic substances in the water.