JPH07303802A - Diaphragm deaeration device - Google Patents

Abstract

PURPOSE:To make a device compact and at a low cost by providing a single means to send a liquid under pressure which performs the works of a means to send under pressure a liquid into a membrane module and a means to send under pressure a liquid into an aspirator, without deteriorating a deaeration capability. CONSTITUTION:Piping is provided to connect an deaeration port linking with space adjacent to the exterior of a membrane module for liquid deaeration, to an aspirator 3 (decompression means for deaeration). Further, the water discharge side of a pressurizing pump 2 (a means to send a liquid under pressure) is connected to the liquid feed port 8 of the membrane module 1 and the aspirator 3 using piping. That is, piping is so arranged for a flow path for liquid to be sent under pressure from the pressurizing pump 2 that the flow path is divided into a membrane module side flow path 7 and an aspirator side flow path 8. In addition, flow control valves 5, 6 should preferably be provided in the membrane module side flow path 7 and the aspirator side flow path 8. Thus, it is possible to obtain water from which oxygen is deaerated from the liquid discharge port 10 of the membrane module 1 by running water into the membrane module 1 and the aspirator 3 using the pressurizing pipe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm type deaerator for removing a gas dissolved in a liquid such as water or a soft viscous fluid (hereinafter collectively referred to as a liquid), and a device for degassing water by using the device. It relates to a method of degassing oxygen. The apparatus of the present invention is used for removing gases such as oxygen, nitrogen, carbon dioxide, chlorine and hydrogen sulfide from a liquid, deoxidation from boiler feed water, deoxidization of semiconductor cleaning water, and red water in clean water by deoxidation. Prevention,
It can be used in many fields such as prevention of microbial propagation of stored water, extermination of soil-living organisms by suffocation, removal and prevention of air bubbles, and wastewater treatment such as hydrogen sulfide removal.

[0002]

2. Description of the Related Art A diaphragm-type degassing method has been known as a method for reducing or removing a gas dissolved or dispersed in a liquid. In this method, a liquid to be treated is caused to flow through one side of a membrane module that is permeable to gas and volatile substances but not liquid, and depressurized on the other side.
This is a method for easily degassing by utilizing the difference in gas permeation rate to reduce or remove the gas dissolved or dispersed in the liquid. The conventional diaphragm-type deaerator used in this method includes, in addition to the liquid degassing membrane module, means for pumping liquid into the module and depressurizing means for degassing the liquid pumped into the membrane module. As a component, a pressure pump was often used as a liquid pressure-feeding means, and a vacuum pump such as a water-sealed vacuum pump, an oil rotary vacuum pump, or a diaphragm vacuum pump was often used as a decompression means.

[0003]

However, since this conventional diaphragm type deaerator requires a plurality of pumps such as a pressurizing pump and a vacuum pump, there is a limit to the compactness of the apparatus and it can be moved more easily. In order to make it available in various fields, it is necessary to reduce the size and cost of the device without changing the essential function of the membrane-type degassing method and device.

[0004]

As a result of intensive studies to solve the above problems, the present invention uses an aspirator as a depressurizing means, and a liquid pressure feeding means into the membrane module and a liquid pressure feeding means into the aspirator. The present invention has been completed by finding that by performing a single liquid pressure feeding means, it is possible to reduce the number of constituent elements of the apparatus without lowering the degassing ability, and to realize a compact size and low cost of the apparatus. That is, the present invention relates to a membrane degassing apparatus which incorporates a liquid degassing membrane module, a liquid pressure feeding means into the membrane module, and a degassing depressurizing means from the liquid pressure fed into the membrane module. The degassing depressurizing means has a depressurizing means by pumping liquid to an aspirator, and the liquid pumping means into the membrane module and the liquid pumping means into the aspirator are provided by one liquid pumping means. (EN) A diaphragm type deaerator characterized by having a mechanism for performing it.

The present invention will be described in detail below. The membrane material of the liquid degassing membrane module used in the present invention is not particularly limited, but the membrane may partially include a hydrophilic portion, but it is basically required to be hydrophobic. When the membrane is hydrophilic, water penetrates and penetrates inside the membrane, and therefore is not used as a diaphragm. Therefore, the diaphragm may be a membrane that removes gas or volatile substances dissolved or dispersed in the liquid without allowing water to pass through as a liquid, such as poly-4-methylpentene-1, polypropylene. , Polyolefin such as polyethylene, polyvinylidene fluoride,
Fluorine-based polymers such as polytetrafluoroethylene (PTFE) and perfluoroalkoxy polymer (PFA), polyacetal, polyphenylene oxide (PP)
O), polyphenylene sulfide (PPS) and other polyethers, polythioethers, polyvinyl chloride (PV
C), chlorine-containing polymers such as polyvinylidene chloride, and further polyether ether ketone, polysulfone polyether sulfone, silicone resin, polyimide and the like can be exemplified, but other copolymers may be used.

Regarding the morphology of the membrane, when degassing from the liquid pumped into the membrane module, non-porous homogeneous membranes, heterogeneous membranes and composite membranes with non-porous layers have a lower water vapor transmission rate and are more permeable. Although it is preferable because it can exhibit the characteristics of degassing, a porous membrane having fine pores on the surface can be used as long as the liquid does not leak. The shape of the membrane is not particularly limited, and a hollow fiber membrane shape typified by a tube shape or a flat sheet shape like a sheet can be applied, but the membrane area that affects the compactness as a membrane module and the throughput of liquid degassing In view of the above, the hollow fiber membrane shape is particularly preferable.

There is no regulation on the form of the membrane module when the hollow membranes are bundled and modularized. For example, the hollow fibers are incorporated into the module element in parallel bundles, the hollow fibers are combined with each other or other hollow fibers. Incorporating a three-dimensional braid such as a braided or other sheet-shaped net with threads and its bundle or weight into a module element, and a three-dimensional braid with a hollow fiber twill wound on a core in an ELEMET housing Any shape object such as a saliva can be used. Furthermore, although it may be an "internal perfusion type" that pumps the liquid to be degassed inside the hollow fiber membrane (inner diameter side) of this membrane module, it is an "external perfusion type" that pumps the liquid to the outside (outer diameter side) of the membrane. Although it may be a membrane module, it is not particularly limited as long as it is selected in consideration of usage conditions such as the amount of liquid degassed, the feed pressure of the liquid and the pressure loss.

Examples of the liquid pressure-feeding means for supplying the liquid into the membrane module include not only a water faucet directly connected to supply of clean water but also a means for mechanically pressure-feeding a pressurized liquid feed pump or the like. The means is not particularly limited to these as long as the desired liquid amount is sufficient and an appropriate amount can be pressure-fed, but a pressure pump is used because the pressure-feeding force can be appropriately adjusted according to the degassing application. It is preferable.
Examples of the pressure pump for liquid pressure feeding include a tube pump, a diaphragm pump, a magnet pump, a piston pump, a plunger pump, a cascade pump, a submersible pump, and a hand pump.

As the degassing decompression means from the liquid degassing module in the present invention, an aspirator for sucking air or other gas by a jet of liquid is used. The details of the decompression mechanism of the aspirator and the principle itself are omitted in the present specification because they are described in various documents and manuals, but the pump uses a pressure difference due to a water flow in a pipe having an uneven thickness. Since there are no moving parts in the aspirator, there is no mechanical failure, and the degree of pressure reduction up to its saturated vapor pressure can be easily obtained according to the temperature of the liquid water to be pumped without requiring a power source. Since the size of the vacuum pump used as the air pressure reducing means is a fraction of one to several tenths, it is advantageous as compared with the conventional vacuum pump.

As the material of the aspirator, inexpensive and convenient polyolefin resin such as polyethylene and polypropylene, polytetrafluoroethylene (PTFE) having excellent chemical resistance, austenitic stainless steel typified by 18Cr-8Ni, and glass are used. Although various materials such as manufactured products are commercially available, any one may be selected depending on the type of the pressure-fed liquid passing through the aspirator and the intended use.

In the apparatus of the present invention, the same liquid pressure-feeding means as the liquid pressure-feeding means into the aspirator is used. That is, the liquid is pumped into the aspirator and the membrane module by one liquid pumping means, preferably by one pressurizing pump. For example, the flow path of the pressure-fed liquid is divided into a flow path side in which the liquid degassing membrane module is incorporated and a flow path side in which an aspirator as a degassing decompression means is incorporated, and one of them is inside the liquid degassing membrane module. When the other is used as the pressure feeding means for supplying liquid to the aspirator and the other is used as the depressurizing means for degassing by feeding the liquid into the aspirator, the pressure feeding of the liquid is performed by one pressurizing pump as the liquid pressure feeding means to both flow paths. The present invention can be easily carried out by carrying out.

Regarding the distribution ratio of the pressure-fed fluid between the aspirator side and the membrane module side, the diaphragm degassing device is substantially dependent on the degree of pressure reduction in the aspirator, the degassing capacity of the membrane degassing module, the degassing treatment flow rate, and the like. It can be freely decided depending on the convenience of use. This adjustment can be easily carried out by inserting a flow control valve between the liquid inlet of the aspirator and the membrane module and the liquid pumping means.

An example of a specific structure of the diaphragm type deaerator will be described below with reference to the drawings. As the basic constituent elements of the present device, the membrane module 1, the pressurizing pump 2 (liquid pumping means),
An aspirator 3 (pressure reducing means for degassing) is piped as shown in FIG. That is, the degassing port 11 connected to the space in contact with the outside of the membrane module 1 and the aspirator 3 are piped, and the drain side of the pressure pump 2 is piped to the liquid water supply port 9 of the membrane module 1 and the aspirator 3. The flow path of the liquid pumped from the pressure pump 2 is arranged so as to be divided into the membrane module side flow path 7 and the aspirator side flow path 8. Further, the flow rate adjusting valve 5 is provided in the membrane module side flow passage 7 and the aspirator side flow passage 8.
And 6 are preferably provided. In addition to these, addition of appropriate parts such as a flow meter, a vacuum gauge, a pressure reducing valve, an opening / closing valve, a strainer, and the like does not impose any restrictions. Further, it is desirable to provide a water supply tank 4 for storing return water from the aspirator 3 and makeup water from the outside of the diaphragm type deaerator in front of the pressurizing pump 2 in order to effectively use the return water. Depending on the circumstances, the original function of the diaphragm-type deaerator does not deteriorate even if the water tank is not provided. A water temperature controller may be separately attached to the water supply tank 4 in order to keep the water temperature constant.

In addition, the present invention also includes a method of deaerating oxygen from water using such a deaerator. For example, water is supplied by the pressure pump 2 to the membrane module 1 and the aspirator 3
Oxygen-deaerated water can be obtained from the liquid drainage port 10 of the membrane module 1 by flowing it into the water. The oxygen concentration of the degassed water varies depending on the water temperature, the amount of water flowing to the membrane module, the amount of water flowing to the aspirator, the treatment capacity of the membrane module itself, etc., but can be about 0.1 to 1 ppm.

[0015]

[Operation] Since the decompression by the aspirator is the necessary and sufficient amount for degassing, the degassing capacity of the device is sufficient,
At the time of degassing, a power source other than the liquid pressure feeding means into the membrane module is unnecessary.

[0016]

EXAMPLES The degassing effect of the diaphragm type degassing apparatus of the present invention will be described in detail with reference to the following examples. [Example 1] (Separation type deaerator) As a membrane module for liquid deaerating, 63,000 hollow fiber heterogeneous membranes made of poly-4-methylpentene-1 having an outer diameter of 250 µm and an inner diameter of 180 µm were filled.
Cylindrical membrane module S with φ100 mm and length of 500 mm
EPAREL MJ-515 (manufactured by Dainippon Ink and Chemicals, Inc.) was prepared. This hollow fiber membrane module feeds water pressure of 2 kgf / cm ² · G, feed water temperature of 20 ° C, feed water amount of 500 L / h from one end of the module, and the pressure on the gas phase side across the membrane is 33 torr. By decompressing to the other side, from the other side of the module, the saturated dissolved oxygen concentration of about 8.8 ppm by weight at a water temperature of 20 ° C., which is shown in various documents, was reduced to about 0.5 ppm by weight. It has the ability to obtain steam. A structural diagram of this hollow fiber membrane module 1 is shown in FIG. After concentrating and inserting the hollow fiber membranes 12 bundled substantially in parallel to the cylindrical module housing 13, both ends of the hollow fiber membranes are sealed with resin 14, and the inner surface of the hollow fiber membranes is attached to the end face 15 of the sealing portion. Leave it open. The end cap 16 is attached to the module housing,
A liquid water supply port 9 connected from one end of the hollow fiber membrane to the inside of the hollow fiber, a liquid drainage port 10 on the other end side, and a degassing port 11 connected to a space in contact with the outside of the hollow fiber are provided. This hollow fiber membrane module was piped as shown in FIG. As the liquid pumping means into the membrane module, a water feed pump 2 having a motor output of 0.4 kW and having a pumping performance of a predetermined amount of water to the membrane module 1 and the aspirator 3 as the degassing depressurizing means was used. Therefore, the output of the pump motor used in this device is 0.4K.
It was only W.

(Degassed Water Production Example 1) 13 ° C. tap water (dissolved oxygen concentration 10 ppm) was introduced into the water supply tank 4 as raw water, and the flow rate was adjusted by the flow rate control valve 5 connected to the membrane module side flow path 7. 2.5 L / min. , Aspirator channel 8
40 L / mi with the flow control valve 6 connected to
n. Then, the pressure pump 2 was operated. At this time, the dissolved oxygen concentration of the degassed water drained from the liquid drain port 10 of the membrane module 1 was measured and found to be 0.6 ppm.
A portable dissolved oxygen meter DO-11P manufactured by Toa Denpa Kogyo Co., Ltd. was used to measure the dissolved oxygen concentration. Also, the Bourdon tube vacuum gauge in the pipe has a vacuum degree of 2 by the aspirator.
It was shown to be 0 torr.

(Production Example 2 of deaerated water) In the same manner as in Production Example 1, tap water having a supply water of 20 ° C. was supplied to the membrane module side at 7 L /
min. , 40 L / min. To the aspirator side. The dissolved oxygen concentration of the degassed water obtained was adjusted to 0.4 ppm. The dissolved oxygen concentration was measured using the above-mentioned dissolved oxygen meter DO-11P, and the Bourdon tube vacuum gauge in the pipe had an aspirator vacuum degree of 25 torr.
It was shown that it was r.

COMPARATIVE EXAMPLE 1 Next, a comparative example with a conventional diaphragm type deaerator will be shown. (Membrane-type deaerator with water-sealing pump) Fig. 3 shows the configuration of the diaphragm-type deaerator with water-sealing pump used in this comparative example. As the liquid degassing membrane module, the same membrane module SEPARELMJ-515 (manufactured by Dainippon Ink and Chemicals, Inc.) as in Example 1 was prepared. Degassing port 1 of membrane module 1
A 0.45 kW water-sealed pump 17 having a minimum required displacement was connected to and piped in 1. Next, as a liquid pumping means into the membrane module, a 0.4 KW pressurizing pump 2 having a pumping performance of a predetermined amount of water to the membrane module 1 was prepared.
Therefore, the total output of the pump motor used in this device is 0.
It became 85 kW. A water supply tank 4 for storing return water from the water-sealed pump 17 and makeup water from the outside of the diaphragm type deaerator was prepared in front of the pressurizing pump 2. Further, flow rate control valves 18 and 20 are provided on the secondary side of the pressurizing pump 2, that is, on the primary side (water supply side) of the membrane module 1 and on the primary side (water supply side) of the water-sealed pump 17.

(Comparative example 1 for producing deaerated water) Water supply tank 12
Of the raw water is maintained at 20 ° C., the water supply pump to the membrane module 1 is operated, and the flow rate is adjusted to 7 L / min. Adjusted to. Next, the flow rate of the sealed water is adjusted to 2 L / m by the flow control valve 20.
in. Membrane degassing was performed from the degassing port 11 of the membrane module with a water-sealed pump adjusted to some extent. At this time, when the dissolved oxygen concentration of the degassed water drained from the liquid drain port 10 of the membrane module 1 was measured, it was 0.5 ppm. The dissolved oxygen concentration was measured using the above-mentioned dissolved oxygen meter DO-11P, and the degree of vacuum was 25 t according to the Bourdon tube vacuum gauge in the pipe.
It was orr.

[0021]

EFFECT OF THE INVENTION The diaphragm type deaerator of the present invention has only the membrane module, the liquid pumping means and the aspirator as the basic constituent elements, and is a pressurization for pumping the liquid, which is indispensable in the conventional diaphragm type deaerator. A plurality of pumps such as a pump and a vacuum pump as a diaphragm type deaeration means are unnecessary, and the number of constituent elements of the apparatus has been reduced without changing the essential functions. And cost reduction of equipment. Further, since the liquid pressure-feeding means and the degassing pressure-reducing means are formed by a single liquid pressure-feeding means, there are effects such as running cost reduction such as electricity amount of the pump motor used in the degassing device and energy saving. As described above, the device can be easily moved and can be used in many fields.

[Brief description of drawings]

FIG. 1 shows the configuration of a diaphragm-type deaerator using the hollow fiber membrane module of the present invention.

FIG. 2 shows a structural schematic diagram of a hollow fiber membrane module used in the present invention.

FIG. 3 shows the configuration of a water seal pump type diaphragm deaerator using a conventional hollow fiber membrane module.

[Explanation of symbols]

 1 ... Hollow fiber membrane module 2 ... Pressurizing pump 3 ... Aspirator 4 ... Water supply tank 5 ... Flow control valve 6 ... Flow rate Control valve 7: Membrane module side flow path 8: Aspirator side flow path 9: Liquid water supply port 10: Liquid drain port 11: Degassing port 12 ... Hollow fiber membrane 13 ... Module housing 14 ... Sealing resin 15 ... End face of sealing part 16 ... End cap 17 ... Water-sealed pump 18 ・ ・ ・ ・ ・ Flow control valve 19 ・ ・ ・ ・ ・ Flow control valve 20 ・ ・ ・ ・ ・ Flow control valve

Claims (5)

[Claims] 1. A diaphragm type deaerator comprising a liquid degassing membrane module, a liquid pressure feeding means into the membrane module, and a depressurizing means for degassing the liquid pressure fed into the membrane module. The degassing depressurizing means has a depressurizing means by pumping liquid to an aspirator, and the liquid pumping means into the membrane module and the liquid pumping means into the aspirator are provided by one liquid pumping means. A diaphragm type degassing device characterized by having a mechanism for performing the degassing. 2. The liquid pressure degassing means for pumping the liquid into the liquid degassing membrane module and the degassing depressurizing means for pumping the liquid into the aspirator are carried out by the pressure pumping of the liquid by one pressurizing pump. The diaphragm type deaerator described. 3. The diaphragm type deaerator according to claim 2, wherein the flow path of the liquid fed under pressure is divided into a flow path side in which the liquid degassing membrane module is incorporated and a flow path side in which an aspirator is incorporated. 4. The membrane degassing apparatus according to claim 3, wherein the liquid degassing membrane module is a membrane module incorporating a hollow fiber membrane. 5. A method for degassing dissolved oxygen from water using the degassing apparatus according to claim 1.