JPH11244843A - Steam compression type pure water producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce pure water without using heating steam of a boiler by providing a single utility evaporator and a steam compressor for compressing heating medium steam for heating a heat transfer pipe of the evaporator. SOLUTION: A feed water treated with a reverse osmosis device or the like enters into a water storage part 2 of the evaporator 1 and is mixed with concentrated liquid in the heat transfer pipe 3. The mixed liquid is sent to an upper part water chamber 5 by a circulating pump 4 and at the time of flowing down in the heat transfer pipe 3 therefrom, the mixed liquid receives the heat of condensation of the heating steam from outside surface to be evaporated and to generate steam. The remaining concentrated liquid after steam is generated flows down into the water storage part 2 and sent again to the upper part water chamber 5. On the other hand, the generated steam enters into the outside of heat transfer pipe 7 through a mist separator 6 and is condensed on the outside surface of the heat transfer pipe 7. Next, the condensate enters into a pure water storage part 10 and is taken out by a pure water pump 11. The heating steam to be used is elevated in the temp. and the pressure, enters into the outside of the heat transfer pipe 3, gives the heat of condensation to the mixed liquid flowing down in the heat transfer pipe 3 to be condensed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor compression type pure water producing apparatus for producing pure water used in the electronics industry such as the semiconductor industry.

[0002]

2. Description of the Related Art Conventional techniques include a method combining an ion exchange resin and a membrane separation technique and a method using a multiple effect distillation method (Japanese Patent Application No. 9-79277).

[0003]

In a conventional apparatus for producing pure water by a distillation method, heated steam is used as a heat source.
It is common to use boiler steam as the heating steam. In recent years, energy conservation has progressed, and there is little surplus steam in the factory. When a distillation pure water production device is newly installed, a boiler is also newly installed. However, when a new boiler is installed, there is a problem that the exhaust gas amount of the whole factory increases. recent years,
There is a growing interest in the issue of global warming, and in particular, there is a tendency for regulations to increase carbon dioxide emissions from factories. In addition, a new site for installing a boiler will be required.

[0004] Further, as the capacity of the pure water producing apparatus increases, the capacity of the boiler also increases, and the operation and management must be performed by a boiler engineer, and the running cost increases.

[0005] Further, in a pure water production apparatus based on the conventional distillation method, cooling water for condensing steam generated in the final utility is required, and for that purpose, a new cooling tower must be provided.

The present invention has been made in view of the above circumstances, and has as its object to provide a distillation pure water production apparatus capable of producing pure water without using steam for heating a boiler.

[0007]

A first pure water producing apparatus by distillation according to the present invention comprises a single-effect evaporator and a steam compressor for compressing a heat medium vapor for heating a heat transfer tube of the evaporator. Is a pure water production device.

The second apparatus for producing pure water by distillation according to the present invention is provided with a conventional subsystem, ie, an ultraviolet oxidizer, a cartridge polisher downstream thereof, and a downstream thereof, downstream of the first apparatus for producing pure water by distillation. This is an ultrapure water production device that combines a downstream ultrafiltration device.

In the above-mentioned pure water producing apparatus, water, ammonia, chlorofluorocarbon or the like is used as a heat medium.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vapor compression type pure water producing apparatus according to the present invention will be specifically described with reference to embodiments.

Example 1 [FIG. 1: Vapor compression pure water production apparatus] 1) The flow of a water (pure water) system is as follows.

The feed water treated by the reverse osmosis device or the decarboxylation / degassing device, or the feedwater pretreated by the reverse osmosis device and the decarboxylation / degassing device is supplied to the bottom of the feed water side of the evaporator (1). Into the water reservoir (2). The water supplied to the sump (2)
It is mixed with the remaining concentrate that has generated steam in the heat transfer tube (3). This mixture is passed through the circulation pump (4) to the upper water chamber.
(5), from which it flows down in a thin film form inside the heat transfer tube (3), receives the latent heat of condensation of heated steam from the outer surface of the tube (3), evaporates at a temperature of about 55 ° C, and generates steam. I do. The concentrated liquid remaining after the generation of water vapor flows down to the water reservoir (2), is mixed with the supply water as described above, and most of it is sent to the upper water chamber (5) via the circulation pump (4).

The remaining mixture is withdrawn at a certain rate so that scale does not deposit on the heat transfer tube (3). The extraction ratio is determined by the concentration of the scale component contained in the supply water.

The steam generated in the heat transfer tube (3) on the supply water side passes through the mist separator (6) and enters the outside of the heat medium side heat transfer tube (7). Most of the mist accompanying the water vapor is removed by the mist separator (6). Most of the pure steam from which the water mist has been removed condenses on the outer surface of the heat transfer tube (7).

The pure vapor condensing section is provided with a vent pipe (8) for extracting a small amount of non-condensable gas contained in the supply water, and is bleed by a vacuum pump (9). The condensate enters the pure water reservoir (10) close to the heat medium side condenser. The condensate collected in the pure water reservoir (10) is supplied to the pure water pump (1
Extracted in 1).

The condensate extracted by the pure water pump (11)
Resistivity 15MΩ · cm (resistivity of theoretical pure water 18.24M
Ω · cm. The resistivity in this specification is pure water of the order of 25 ° C.).

2) Flow of heating medium (heating steam) system The heating steam whose temperature has been raised and pressurized by the compressor (12) is supplied to the heat transfer tube (3).
Go outside. Heat transfer tube (3)
(3) The liquid mixture flowing down in the form of a thin film is given latent heat of condensation to condense at a temperature of about 60 ° C. A vent pipe (17) for evacuating the system leak air is provided in the condensing section of the heated steam, and is extracted by a vacuum pump (9). The condensate of the heated steam passes through the condensate connecting pipe (13) and enters the liquid reservoir (14) at the bottom of the heating medium. The condensate entering the liquid reservoir (14)
(7) Mix with the remaining concentrate that generated steam. The mixed liquid is sent to the heat medium side upper liquid chamber (16) via the circulation pump (15). The mixed solution sent to the upper liquid chamber (16) is transferred to the heat transfer tube (7).
It flows down in a thin film form, receives the latent heat of condensation of pure steam from the outer surface of the heat transfer tube (7), and evaporates at a temperature of about 50 ° C. to generate steam. The generated steam enters the compressor (12),
It is boosted.

The heating medium (heating steam) system is operated in a closed cycle. If the heat medium (water) is reduced by bleeding,
Heat medium (pure water) is supplied.

Embodiment 2 [FIG. 2: Ultrapure Water Producing Apparatus] FIG. 2 shows an apparatus for producing ultrapure water used for wafer cleaning in a semiconductor manufacturing process. The pure water produced in Example 1 (resistivity 1
In order to further increase the purity to 5 MΩ · cm), the vapor compression type pure water production apparatus of Example 1 is combined with a conventional subsystem.

The subsystem includes an ultraviolet oxidizer (18) for reducing the TOC component from about 10 ppb to 1 ppm or less, a cartridge polisher (19) for removing trace metal ions downstream of the apparatus, and an extraordinary method for removing fine particles downstream of the apparatus. It is composed of a filtration membrane (20). The ion exchange resin (19) contains a non-regenerated ion exchange resin.

As described above, by combining the vapor compression pure water production apparatus of the first embodiment with the subsystem, it is possible to produce ultrapure water having a resistivity of 18.2 MΩ · cm or more, which is extremely close to the resistivity of theoretical pure water. Can be.

[0022]

The steam compression pure water producing apparatus according to the present invention does not use boiler steam as heating steam, and has the following effects.

1) The amount of exhaust gas from the factory does not increase.

2) There is no need to newly install a boiler.

3) Therefore, there is no need for operation and management by a boiler engineer, and no running cost is required.

4) Also, a cooling tower is not required.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a vapor compression type pure water production apparatus.

FIG. 2 is a schematic diagram showing an ultrapure water production apparatus.

[Explanation of symbols]

 [Figure 1] 1: Evaporator 2: Water reservoir 3: Heat transfer tube 4: Circulation pump 5: Water chamber 6: Mist separator 7: Heat transfer tube 8: Vent tube 9: Vacuum pump 10: Pure water reservoir 11: Pure water Pump 12: Compressor 13: Condensate connecting pipe 14: Liquid reservoir 15: Circulating pump 16: Liquid chamber 17: Vent pipe [Fig. 2] 18: Ultraviolet oxidizer 19: Cartridge polisher 20: Ultrafiltration membrane

Claims (2)

[Claims] 1. A vapor compression pure water production apparatus comprising a single-effect evaporator and a vapor compressor for compressing a heat medium vapor for heating a heat transfer tube of the evaporator. 2. Ultrapure water production comprising a combination of an ultraviolet oxidation device, a cartridge polisher downstream thereof, and an ultrafiltration device downstream thereof downstream of the vapor compression pure water production device according to claim 1. apparatus.