JP2023104681A - Deaeration membrane device, ultrapure water manufacturing apparatus and ultrapure water manufacturing method - Google Patents

Abstract

To provide a deaeration membrane device capable of confirming the degree of vacuum on the secondary side of the deaeration membrane device.SOLUTION: Feed water is supplied into a water phase chamber 3a of a deaeration membrane module. A pipeline 5, branch pipelines 10, 20, and vacuum pumps 14, 24 are installed so as to decompress a vapor phase chamber 3b, and valves 11, 21 are installed on the pipelines 10, 20. When switching actuation of the vacuum pumps 14, 24, the valves 11, 21 are switched by a controller 6. Vacuum gauges 13, 23 are installed on pipelines 12, 22 between the valves 11, 21 and the vacuum pumps 14, 24.SELECTED DRAWING: Figure 1

Description

The present invention relates to a degassing membrane device, and more particularly to a degassing membrane device having a plurality of vacuum pumps. The present invention also relates to an ultrapure water production apparatus and an ultrapure water production method using this degassing membrane apparatus.

Conventionally, as a system for producing ultrapure water, which is used as water for cleaning semiconductors, etc., raw water such as industrial water, city water, and well water is subjected to coagulation, pressure flotation (sedimentation), filtration (membrane Filtration) equipment, etc. to remove suspended solids, colloidal substances, high-molecular-weight organic substances, hydrophobic organic substances, etc. There are some that are treated with a primary pure water system consisting of a device, or a membrane degassing device and a two-stage RO membrane separation device.

The RO membrane separator removes salts as well as ionic and colloidal TOC. The ion exchange device removes salts and TOC components adsorbed or ion-exchanged by the ion exchange resin.

The membrane degassing device divides the inside into an aqueous phase chamber and a gas phase chamber with a hydrophobic polymer gas permeable membrane (degassing membrane), and the gas phase chamber is decompressed by a vacuum pump, and the water flows into the aqueous phase chamber. It removes gases such as oxygen in the treated water by permeating through the membrane.

JP-A-10-309566 JP-A-2002-355683

The vacuum pump of the degassing membrane device in the ultrapure water system must be operated continuously to keep the primary side piping always in a vacuum state in order to keep the dissolved oxygen concentration, which is the required quality of ultrapure water, below the standard value. is necessary. Therefore, in preparation for failure such as tripping of the vacuum pump, a backup machine (backup vacuum pump) is installed. The standby machine and the main machine (vacuum pump) are connected to the degassing membrane device through a switching valve.

However, when switching from the main unit to the standby unit before the degree of vacuum in the standby unit rises (sufficiently high), the secondary side (reduced pressure side) of the degassing membrane device may become depressurized. As a result, the function of the degassing membrane device deteriorates, and the ultrapure water DO (dissolved oxygen) concentration does not reach the required water quality.

In addition, even when the pump is manually switched during maintenance of the vacuum pump, the switching operation is performed in a state in which it is not possible to confirm that the degree of vacuum has risen, and there is a risk that the water quality will not be achieved.

The present invention is characterized by providing a degassing membrane device capable of confirming the degree of vacuum on the secondary side of the degassing membrane device.

One aspect of the present invention is to provide a degassing membrane device capable of switching between the main vacuum pump and the standby vacuum pump when the degree of vacuum on the secondary side of the degassing membrane device is sufficiently high. Make it an issue.

An object of one aspect of the present invention is to provide an ultrapure water production apparatus and an ultrapure water production method using such a degassing membrane apparatus.

The gist of the present invention is as follows.

[1] a deaeration membrane module having an aqueous phase chamber and a gas phase chamber separated by a deaeration membrane;
In a deaeration membrane device having a vacuum pump for reducing the pressure in the gas phase chamber,
A plurality of the vacuum pumps are installed,
Piping and valves are provided for communicating each vacuum pump with the gas phase chamber,
A degassing membrane device, comprising a vacuum gauge for detecting the degree of vacuum between the valve and the vacuum pump.

[2] A control means is provided for controlling the valve so that the other vacuum pumps are stopped while one vacuum pump is operating and the operating vacuum pumps are communicated with the gas phase chamber. cage,
The control means, when switching the operating vacuum pump, starts the other vacuum pump before stopping the operating vacuum pump;
after the degree of vacuum in the pipe communicating the other vacuum pump with the gas phase chamber reaches a specified degree of vacuum or more, the vacuum pump that is in operation is stopped and the communication with the gas phase chamber is cut off; The degassing membrane device of [1] that communicates with the gas phase chamber of another vacuum pump.

[3] A take-out pipe for taking out degassed water from the aqueous phase chamber of the degassing membrane module is provided,
When the degree of vacuum in the pipe connecting the other vacuum pump to the gas phase chamber does not reach a specified degree of vacuum even after a predetermined time has elapsed after the other vacuum pump is started, the degassing membrane The degassing membrane device according to [2], which has means for causing the degassed water flowing out of the aqueous phase chamber of the module to flow out to a discharge pipe separate from the take-out pipe.

[4] An ultrapure water production system comprising the degassing membrane device according to any one of [1] to [3].

[5] An ultrapure water production apparatus equipped with the degassing membrane device of [3], wherein the discharge pipe allows the degassed water to flow into a primary pure water tank of the ultrapure water production apparatus. The ultrapure water production equipment provided.

[6] A method for producing ultrapure water using the ultrapure water production apparatus of [4] or [5].

The degassing membrane device of the present invention is equipped with a vacuum gauge, and can detect the degree of vacuum on the secondary side (reduced pressure side) of the degassing membrane device. Therefore, according to the degassing membrane apparatus of the present invention, when switching the vacuum pump from the main unit to the standby unit, the switching can be performed after the degree of vacuum of the standby unit becomes sufficiently high.

According to the ultrapure water production apparatus and the ultrapure water production method of the present invention, ultrapure water with a low DO (dissolved oxygen) concentration can be produced stably.

1 is a configuration diagram of a degassing membrane device according to an embodiment; FIG. 1 is a configuration diagram of an ultrapure water production apparatus according to an embodiment; FIG. It is a block diagram of the degassing membrane apparatus which concerns on another embodiment. FIG. 4 is a configuration diagram of an ultrapure water production apparatus according to another embodiment;

Embodiments will be described below with reference to the drawings.

FIG. 1 shows the configuration of a degassing membrane device 1 according to an embodiment.

Water is supplied to the aqueous phase chamber 3 a of the degassing membrane module 3 through the water supply pipe 2 . The deaeration membrane module 3 has an aqueous phase chamber 3a and a gas phase chamber 3b separated by a deaeration membrane 3m. The gas phase chamber 3b is depressurized by a vacuum pump 14 or 24, which will be described later.

Gas components in the water permeate through the degassing membrane 3m while flowing in the water phase chamber 3a. Degassed water is taken out through the pipe 4 . Although not shown, means for supplying nitrogen gas to the degassing membrane module is provided in order to lower the oxygen partial pressure and further reduce the DO concentration of the degassed water.

A pipe 5 is connected to the gas phase chamber 3b to reduce the pressure in the gas phase chamber 3b. The pipe 5 branches into pipes 10 and 20 . Vacuum pumps 14 and 24 are installed at the ends of the pipes 10 and 20, respectively.

Valves 11 and 21 are provided in the middle of pipes 10 and 20 . Vacuum gauges 13, 23 are provided to detect the pressure in lines 12, 22 between valves 11, 21 and vacuum pumps 14, 24, respectively. Detection signals from the vacuum gauges 13 and 23 are input to the controller 6, which controls the valves 11 and 21 and the vacuum pumps 14 and 24. FIG.

During normal operation of the degassing membrane device 1, one of the vacuum pumps 14, 24 is operating and the other is stopped. When the vacuum pump 14 is operating, the valve 11 is open and the valve 21 is closed. When the vacuum pump 24 is operating, the valve 11 is closed and the valve 21 is opened.

The controller 6 monitors the pressure detected by the vacuum gauge 13 while the vacuum pump 14 is operating. When the degree of vacuum in the pipe 12 detected by the degree of vacuum gauge 13 falls below a predetermined value, it is assumed that the vacuum pump 14 has failed, and the vacuum pump 14 is stopped and the vacuum pump 24 is operated.

In this case, before closing the valve 11, opening the valve 21, and stopping the vacuum pump 14, the vacuum pump 24 is started, and the degree of vacuum in the pipe 22 detected by the degree of vacuum gauge 23 reaches the specified value. Wait until the above is reached. After the degree of vacuum in the pipe 22 reaches a specified value or higher, the valve 21 is opened, the valve 11 is closed, and the vacuum pump 14 is stopped.

As a result, the vacuum pumps 14 and 24 are switched without reducing the degree of vacuum in the gas phase chamber 3b of the degassing membrane module 3 at all or little. The same procedure is followed when switching the operating vacuum pump from the vacuum pump 24 to the vacuum pump 14 .

In the above explanation, the vacuum pump is switched due to failure of the vacuum pump, but the same procedure is performed when switching the vacuum pump due to periodic inspection of the vacuum pump or the like.

FIG. 2 shows an example of the configuration of a sub-system (secondary pure water apparatus) of an ultrapure water production apparatus equipped with the degassing membrane apparatus 1 described above.

The primary pure water in the primary pure water tank 30 is pumped by a pump 31, organic matter is decomposed by UV oxidation in a UV oxidation device 32, ionic impurities are removed in an ion exchange device 33, and then degassed. The water is passed through the membrane device 1 and degassed. Fine impurities are removed from the degassed water by the UF membrane device 34 to become ultrapure water, which is sent to a point of use (not shown).

Since the degassing membrane device 1 is employed as the degassing membrane device in this ultrapure water production apparatus, degassed water having a specified water quality or higher is sent from the degassing membrane device 1 to the UF membrane device 34. Thus, ultrapure water with stable water quality is produced.

FIG. 3 shows the degassing membrane device 1 of FIG. Apparatus 1A is shown. A valve 8 is provided in the pipe 7 . A valve 9 is also provided in the pipe 4 .

When the vacuum pump to be operated is switched from one to the other, if for some reason the degree of vacuum in the piping of the vacuum pump to be newly operated does not become sufficiently high even after the passage of a predetermined time, the controller 6 closes the valve 9 is closed, valve 8 is opened, and degassed water with a high dissolved gas concentration is discharged from pipe 7 to the outside of the system.

A three-way valve may be installed instead of the valves 8 and 9.

FIG. 4 shows an example of an ultrapure water production system equipped with this degassing membrane device 1A. In this ultrapure water production apparatus, the water discharged from the pipe 7 is returned to the primary pure water tank 30 for reuse.

Other configurations in FIGS. 3 and 4 are the same as in FIGS. 1 and 2, and the same reference numerals denote the same parts.

The above embodiment is an example of the present invention, and the present invention may be configured in a manner other than the above. For example, in the above embodiment, the pipes 10 and 20 are provided with the valves 11 and 21 respectively. Although two vacuum pumps are installed in parallel in the above embodiment, three or more vacuum pumps may be installed in parallel. Moreover, the ultrapure water production apparatus may be provided with equipment other than the above.

Reference Signs List 1, 1A degassing membrane device 3 degassing membrane module 6 controller 11, 12 valve 13, 23 vacuum gauge 14, 24 vacuum pump 32 UV oxidation device 33 ion exchange device

Claims (6)

a deaeration membrane module having an aqueous phase chamber and a gas phase chamber separated by a deaeration membrane;
In a deaeration membrane device having a vacuum pump for reducing the pressure in the gas phase chamber,
A plurality of the vacuum pumps are installed,
Piping and valves are provided for communicating each vacuum pump with the gas phase chamber,
A degassing membrane device, comprising a vacuum gauge for detecting the degree of vacuum between the valve and the vacuum pump. A control means is provided for controlling the valve so that the other vacuum pumps are stopped while one vacuum pump is operating and the operating vacuum pumps are communicated with the gas phase chamber,
The control means, when switching the operating vacuum pump, starts the other vacuum pump before stopping the operating vacuum pump;
after the degree of vacuum in the pipe communicating the other vacuum pump with the gas phase chamber reaches a specified degree of vacuum or more, the vacuum pump that is in operation is stopped and the communication with the gas phase chamber is cut off; 2. The degassing membrane device according to claim 1, which communicates with the gas phase chamber of another vacuum pump. an extraction pipe for extracting degassed water from the aqueous phase chamber of the degassing membrane module,
When the degree of vacuum in the pipe connecting the other vacuum pump to the gas phase chamber does not reach a specified degree of vacuum even after a predetermined time has elapsed after the other vacuum pump is started, the degassing membrane 3. The degassing membrane apparatus according to claim 2, further comprising means for causing the degassed water flowing out of the aqueous phase chamber of the module to flow out to a discharge pipe separate from said take-out pipe. An ultrapure water production system comprising the degassing membrane device according to any one of claims 1 to 3. 4. An ultrapure water production system comprising the membrane degassing device according to claim 3, wherein the discharge pipe is provided to allow the degassed water to flow into a primary pure water tank of the ultrapure water production system. ultrapure water production equipment. An ultrapure water production method using the ultrapure water production apparatus according to claim 4 or 5.

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