JPH0570486B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is applicable to gasoline, kerosene, light oil, heavy oil,
Internal combustion engines such as automobiles and aircraft that mix fuel such as LNG (liquefied natural gas), LPG (liquefied petroleum gas), and city gas with air and burn it as a flammable gas mixture, as well as cement kilns and boilers,
A device for producing oxygen-enriched air that sends oxygen-enriched air to combustion devices such as household gas ranges to increase combustion efficiency, or for chronic bronchitis, emphysema,
The present invention relates to a device for producing oxygen-enriched air as an oxygen supply source useful for oxygen inhalation therapy, etc. for hypoxemic patients with sequelae of pulmonary tuberculosis.

[Prior Art] Conventionally, as a method for producing such oxygen-enriched air, a method using an organic polymer membrane is known. This method attempts to generate oxygen-enriched air by concentrating oxygen in the air by utilizing the difference in gas permeability that passes through organic polymer thin films. If it can be increased to 30-40%,
By using it in a combustion device, it is possible to reduce fuel consumption, thereby saving energy, and it can also be used as an oxygen supply source for medical purposes.

The conventional oxygen production method, cryogenic air separation, compresses and cools the air and then uses the difference in boiling points to perform a fractional distillation operation, which consumes a huge amount of electrical energy. The production of enriched air is a simple process of sending 1 atm of air to one side of the membrane and reducing the pressure to about 0.1 atm on the other side of the membrane to generate air with a high oxygen concentration.
It is attracting attention as an inexpensive method.

Oxygen-enriching membranes that have been announced so far include dimethylpolysiloxane-polycarbonate block copolymer membrane (GE Corporation, USA), polyhydroxystyrene-dimethylpolysiloxane-polycarbonate block copolymer membrane (Matsushita Electric Industry), etc. There is.

However, such conventional membranes have a small amount of gas permeation, and are only applicable to small oxygen inhalers for medical use, and are used in combustion devices that use large amounts of air (e.g.
In the case of a car, the weight ratio of the air and fuel supplied to the engine, that is, the air-fuel ratio, is approximately 15, and the fuel consumption is 10 km /
Assuming that the vehicle is traveling at a constant speed of 40 km/hr, the amount of air required for this combustion is 40/10 x 15 = 60/hr. )
Its application is only at the research stage.

[Problems to be Solved by the Invention] Generally speaking, the properties of polymer membranes are such that polymer membranes with a large oxygen/nitrogen separation coefficient (hereinafter referred to as P _O2 /P _N2 ) are easy to form into thin films. First, polymer films with a small gas permeability coefficient and a large gas permeability coefficient tend to be difficult to form into thin films and have a low P _O2 /P _N2 ratio. In other words, the oxygen permeability coefficient (hereinafter referred to as P _O2 )
is the maximum value among conventionally known polymers (3.52×
10 ^-8 cm ³・cm/cm ²・sec・cmHg; Units are omitted below. ) Organopolysiloxane is P _O2 /
Polyvinyl acetate has a low P _N2 of 1.94, and its thin film formability is limited to 20 to 30 μm. Polyvinyl acetate, which has the highest P _O2 /P _N2 of all polymer films (7.03), can form films of 1 μm or less. Despite this, P _O2 shows a value that is three orders of magnitude smaller, 2.25×10 ^-11 . For this reason, the current situation is to compromise the gas permeability coefficient by copolymerizing organopolysiloxane with other resins from the viewpoint of thin film forming properties.

The present inventors used organopolysiloxane as a base resin and filled it with various powder materials to increase P _O2 to several times that of organopolysiloxane.
He was conducting research to increase the performance by several tens of times and supplement the thin film deposition performance, but in the process, he realized that there was a limit to the development of film materials alone, and that it was necessary to develop an oxygen-enriching device.

The present inventors focused on the fact that oxygen-enriched membranes made of polymer membrane materials have limitations in terms of compromise between P _O2 , P _O2 /P _N2 , and thin film formation performance, and using these membranes. We discovered that it is possible to overcome these limitations by turning them into devices.

It is therefore an object of the present invention to provide an oxygen enrichment device capable of processing large volumes of air.

[Means for Solving the Problems] In order to achieve the above object, the oxygen enrichment device of the present invention has an oxygen permeability coefficient of 1×10 ^-10
The above oxygen/nitrogen separation membrane and parallel array wires,
The separation membrane is formed by alternately laminating and integrating, and the adjacent separation membranes are spaced apart from each other, and the arrangement direction of the wire rods is substantially orthogonal between the upper and lower layers, and the separation membrane is is characterized by consisting of an organopolysiloxane filled with high silica zeolite.

The oxygen enrichment device of the present invention will be explained based on the accompanying drawings.

FIG. 1 is a schematic perspective view of an example of the oxygen enrichment device of the present invention, and FIG. 2 is a schematic diagram showing an oxygen enrichment system using the oxygen enrichment device of the present invention.

FIG. 1 depicts a device 1 consisting of seven oxygen/nitrogen separation membranes each having three layers of an air supply layer and an oxygen-enriched air suction layer.

The oxygen/nitrogen separation membranes 2 are stacked in the Z-axis direction, and between the oxygen/nitrogen separation membranes 2 are parallel wires 3.
are sandwiched and integrated, and these parallel wire rods are arranged alternately in the X-axis direction and the Y-axis direction for each layer. These wire layers need to be orthogonal to each other, but geometrically this does not need to be strictly at 90 degrees; it is sufficient that they are substantially orthogonal, and the angle should be between 80 degrees and 90 degrees.
A range of 100 degrees is good.

From the bottom, the wire layers are X ₁ layer, Y ₁ layer, X ₂ layer,
If there are ₂ layers _of Y, ₃ layers of The oxygen-enriched air that has passed through is taken out from the _X1 layer, _X2 layer, and _X3 layer. In this way, the permeation flow rate increases in proportion to the number of layers, and a large amount of oxygen-enriched air can be obtained.

In FIG. 1, sealing of the end surface opposite to the oxygen-enriched air outflow surface in the X-axis direction is not illustrated, but it is natural that the end surface is sealed for use. Furthermore, since both sides are open in the Y-axis direction, air can flow in through the membrane and nitrogen-enriched air that is no longer needed can be exhausted at the same time.

The production of such oxygen-enriched air can be done, for example, in the second
It can be effectively produced by the example oxygen enrichment system shown in the figure.

That is, the air sent by the blower fan 4 is purified by passing through the filtration filter 5, and is sent into the Y layer of the oxygen enrichment device 1 of the present invention through the piping system 6. Further, the X layer of the device 1 is sucked by the vacuum pump 7 and passes through the oxygen/nitrogen separation membrane, and the oxygen-enriched air is taken out from the vacuum pump through the piping system 8 and passes through the separation membrane. The non-nitrogen enriched air is exhausted from the Y layer of the device, usually on the opposite side of the piping system 6.

As the oxygen/nitrogen separation membrane according to the present invention, poly[1-(trimethylsilyl)-1-propyne] (P _O2
=7.73×10 ^-7 , P _O2 /P _N2 = 1.55; Hereinafter, P _O2 ,
Omit P _O2 /P _N2 and write the numbers in parentheses in this order. ), organopolysiloxane (3.52×
10 ^-8 , 1.94), natural rubber (2.34 x 10 ^-9 , 2.46), polybutadiene (1.9 x 10 ^-9 , 2.95), ethyl cellulose (1.47 x 10 ^-9 , 3.32), ethylene-vinyl acetate copolymer (8.0 ×10 ^-10 , 2.76), low-density polyethylene (2.89 × 10 ^-10 , 2.98), polystyrene (2.01 ×
10 ^-10 , 6.38), polycarbonate (1.4×10 ^-10 ,
4.67) and butyl rubber (1.3×10 ^-10 , 4.0). Among these, organopolysiloxane is
Although the P _O2 /P _N2 ratio is low, the P _O2 value is one to two orders of magnitude higher, making it extremely superior as an oxygen/nitrogen separation membrane, so organopolysiloxane is most preferably used.

Regarding dimethylpolysiloxane, which is the basic system of organopolysiloxane, the present inventors actually measured P _O2 and P _O2 /P _N2 using a gas permeability measuring device, and found that they were (3 to 7) x 10 ^-8 and 1.8, respectively. It was ~2.1.

Poly[1-(trimethylsilyl)-1-propyne] has an order of magnitude higher P _O2 than organopolysiloxane
However, if this problem is solved, it will become a promising oxygen/nitrogen separation membrane according to the present invention, due to the drastic decrease in P _O2 over time, which has delayed its practical application.

The thinner the gas permeable membrane, the higher the permeation flow rate.
As mentioned above, dimethylpolysiloxane has poor ability to form a thin film by itself, and the maximum thickness is 20 to 30 μm. Therefore, it is preferable to coat a porous support membrane with it to form a thin film. Examples of the porous support membrane include porous films made of polypropylene, polysulfone, polyimide, aromatic polyester, and the like.

Furthermore, according to the research conducted by the present inventors, a thin film made by blending and filling high silica zeolite with dimethylpolysiloxane can obtain several times to several tens of times more P _O2 than a dimethylpolysiloxane film. Use is more preferred.

The compositional formula of zeolite is, for example, naturally occurring mordenite is represented by NaO.Al ₂ O ₃・10SiO ₂・6H ₂ O, and synthetic zeolite type A is represented by Na ₂ O ・Al ₂ O ₃・2SiO ₂・4.5H ₂ O. , SiO ₄ tetrahedron and (AlO ₄ ) ^-tetrahedron are combined in a three-dimensional network, and it is a porous crystal body with countless pores with a diameter of about 1 nm. Because it exhibits unique adsorption performance, it is used as a dehydrating agent and desiccant agent. , molecular sieves, adsorbents, catalysts, ion exchange agents, etc. High silica zeolite is also called ZSN-5 type zeroolite and exhibits a large SiO ₂ /Al ₂ O ₃ ratio of 15 or more to infinity. In this,
A well-known zeolite with infinite SiO ₂ /Al ₂ O ₃ is Silicalite ^R [specific formula (SiO ₂ ) ₉₆ ] manufactured by UCC in the United States. The pore structure of this silicalite crystal is an elliptical oxygen atom with a diameter of 0.57 x 0.51 nm.
It has a structure in which a 10-membered ring straight channel is combined with a 10-membered ring zigzag channel with an approximately circular oxygen atom diameter of 0.54 nm, and the present inventors have found that when dimethylpolysiloxane is filled with more than 60% by weight of this channel, P It has been experimentally confirmed that _O2 can be increased several times to several tens of times.

That is, according to actual measurements of P _O2 using a gas permeability measuring device, the dimethylpolysiloxane membrane alone was 4.0×10 ^-8 and the dimethylpolysiloxane membrane filled with 60% silicalite was 15×10 ^-8 to 20×10 ^-8 , a dimethylpolysiloxane membrane filled with 80% by weight of silicalite can obtain a value as high as 40 x 10 ^-8 , and a dimethylpolysiloxane membrane filled with 90% by weight of silicalite can obtain a value as high as 135 x 10 ^-8 . The measured P _O2 /P _N2 values of these films were in the range of 1.8 to 2.1.

The above-mentioned high-silica zeolite-filled dimethylpolysiloxane membrane is a method that compensates for the poor thin film formability of dimethylsiloxane by increasing P _O2 , and the thin film formability is limited to 20 to 30 μm. However, according to the research of the present inventors, thin film forming properties can be improved by blending the poly[1-(trimethylsilyl)-1-propyne] with dimethylpolysiloxane. It has been found that it is possible to obtain several times as much P _O2 as a membrane made of dimethylpolysiloxane alone.
According to the inventors' film-forming experiments, these ratios were 50:50.
When blended at a ratio of , it is possible to form a film of approximately 2 to 3 μm, and the actual measured value of P _O2 at this time is (20 to 30) × 10 ^-8
The actual measured value of P _O2 /P _N2 was 1.8.

Examples of the method for forming the oxygen/nitrogen separation membrane according to the present invention include a solution casting method, a T-die extrusion method, an inflation method, a calendar roll rolling method, and a uniaxial or biaxial stretching method. It will be done.
Further, examples of the method for forming a film on the support film include gravure roll coating, Meyer bar coating, doctor knife coating, reverse roll coating, air knife coating, microgravure coating, and the like.

The thinner the oxygen/nitrogen separation membrane is, the better it is to the extent that it does not cause pinholes when processing a large amount of air. However, if it is not a composite membrane with a porous support membrane, handling From the point of view of ease
It is desirable that the thickness be 1 μm or more. When forming a composite membrane with a porous support membrane, it is preferable to use a membrane with a submicron thickness within a range that does not cause pinholes. The upper limit of the film thickness is 100 μm, preferably about 30 μm from the viewpoint of air throughput.

Examples of the array wire according to the present invention include metal wires made of stainless steel, nickel, copper, nickel silver, brass, phosphor bronze, etc., and polymer linear bodies such as polyester, polyamide, aromatic polyamide, etc. For manufacturing reasons, it is more preferable to use a metal wire that has excellent strength and does not expand or contract.

If the diameter of the array wire is too small, the spacing between the separation membranes will become narrow, which will prevent air from flowing in. If the diameter of the array wire is too small, the spacing between the separation membranes will become large, reducing the separation membrane stacking density and reducing oxygen-enriched air. Since the amount of produced is small, it is disadvantageous that a diameter of φ10 μm to φ3 μm is usually used. Preferably it is in the range of φ50 μm to φ1 mm.

If the pitch of the parallel array lines is too small, it will inhibit the inflow of air, and if it is too large, the spacing between adjacent separation membranes will be hindered and the inflow of air will be inhibited.
Usually, those in the range of 0.5 to 5 mm are used. Particularly desirable is a thickness in the range of 1 to 2 mm.

The method of adhering the array wire and separation membrane is to laminate the uncured separation membrane to the primer-treated array wire and then use a mold press to bond and integrate it, or to adhere it to the cured separation membrane. There is a method of laminating array wires coated with the material and then bonding them together using a mold press, but considering the handling of thin films and the handling of thin films coated on porous supports, the latter method is more practical. It is true.

[Function] According to the oxygen enrichment device configured as described above, the injected air passes through a large number of oxygen/nitrogen separation membranes stacked in multiple stages via array wires, and is enriched with a large amount of oxygen. Nitrogen-enriched air, which is efficiently extracted as air and does not pass through the separation membrane, is easily discharged.

[Example] Production of oxygen/nitrogen separation membrane Liquid dimethylpolysiloxane with a viscosity of 60 Pa・s,
KE1935A/B (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) 40% by weight, high silica gelite, Silicalite ^R
(Manufactured by UCC, trade name) 60% by weight and dissolved in toluene/kerosene mixed solvent.
Teflon ^R was applied as a 50Pa・s solution using Microgravure Coater ^R (Yasui Seiki Co., Ltd., trade name).
Coated on TFE (trade name manufactured by EIDupont) separator, evaporated the solvent at 100℃ x 10 seconds, and cross-linked at 180℃ x 30 minutes to a thickness of 25 μm.
A membrane body of m was obtained.

This high-silica zeolite-filled dimethylpolysiloxane membrane was peeled off from the separator and measured using a pressurized gas permeability measuring device, Gasperm ^R -100 (manufactured by JASCO Corporation, trade name).
P _O2 is 20×10 ^-8 and about 5% of dimethylpolysiloxane
P _O2 /P _N2 was 2.0, which is equivalent to dimethylpolysiloxane.

Manufacture of oxygen-enriched devices Using a PPM wiring device manufactured by Shin-Etsu Polymer Co., Ltd. (transparent touch panel manufacturing device), φ0.2mm SUS-304 wires treated with a silane primer were arranged at a wiring pitch of 1.0mm. 2 on the front and back sides of this wiring.
The above high silica zeolite-filled dimethylpolysiloxane membrane was coated with liquid RTV silicone rubber, TSE-3360 (manufactured by Toshiba Silicone Corporation, trade name).
The upper and lower layers were laminated in multiple layers so that the wiring directions were substantially perpendicular to each other, and then put into a press mold and integrally press-molded.

Next, this end face is polished to form a laminated block-like body measuring 300 mm in length (X-axis direction) x 300 mm in width (Y-axis direction) x 300 mm in height (Z-axis direction), and enriched air flows out in the X-axis direction. The opposite side was sealed with silicone epoxy resin.

Using the device manufactured in this way, the oxygen enrichment system shown in Figure 2 was manufactured and tested.
FCX-SW (manufactured by Fujikura Electric Wire Co., Ltd., product name) Oxygen-enriched air with an oxygen concentration measurement value of approximately 35% is supplied at a flow rate of 100%.
/hr.

[Effects of the Invention] According to the oxygen enrichment device of the present invention, conventional oxygen enrichment devices such as dimethylpolysiloxane films and copolymer films of dimethylpolysiloxane and other resins can be used.
A large amount of air can be separated and processed at once with a structure that uses nitrogen separation membranes or even oxygen/nitrogen separation membranes such as high-silica zeolite-filled dimethylpolysiloxane membranes, and combines them with parallel array wires to stack multiple layers. It is possible to provide an oxygen enrichment device that can be used at a low cost. Furthermore, because of its structure, it can be miniaturized, so it can be used not only for producing small amounts of oxygen-enriched air for medical purposes, but also for combustion by being mounted on an automobile.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the oxygen enrichment device of the present invention. FIG. 2 is a schematic diagram showing an oxidation enrichment system using the oxygen enrichment device of the present invention. DESCRIPTION OF SYMBOLS 1... Oxygen enrichment device, 2... Oxygen/nitrogen separation membrane, 3... Parallel array wire, 4... Delivery fan, 5
...filtration filter, 6, 8...piping system, 7...
vacuum pump.

Claims (1)

[Claims] 1. Oxygen permeability coefficient is 1×10 ^-10 cm ³・cm/cm ²・sec.cm
Oxygen/nitrogen separation membranes of Hg or higher and parallel array wires are alternately laminated and integrated, and the adjacent separation membranes are spaced apart from each other, and the arrangement direction of the wires is substantially orthogonal between the upper and lower layers. An oxygen enrichment device characterized in that it is formed so as to. 2. The oxygen enrichment device according to claim 1, wherein the oxygen/nitrogen separation membrane is made of organopolysiloxane filled with high silica zeolite.