JPH02296703A - Production of oxygen-enriched air - Google Patents

Abstract

PURPOSE:To obtain O2-enriched air with a high O2 separation ability at a low cost without need for the exchange of the adsorbent or gas separation membrane unlike the conventional method by circulating a liq. capable of selectively absorbing O2 in air between a pressure chamber and a reduced-pressure chamber, separating and recovering the O2 dissolved and absorbed by the pressurization of air. CONSTITUTION:Air is pressurized 3 and supplied to the pressure chamber 1 charged with a liq. 2 having O2 absorptivity from its bottom, and diffused into the liq. 2 as fine bubbles. Meantime, a liq. 21 in the reduced-pressure chamber 20 is sent to the chamber 1 from a liq. suction port 25 at the bottom of the chamber 20. When the pressure in the chamber 1 is increased, the gaseous O2 in the fine bubbles is vigorously absorbed by the liq. 2, and the gas layer at the upper part in the chamber 1 is filled with air having a low content of O2. As the liq. 2 is continuously supplied into the chamber 1, the pressure in the chamber 1 is further increased, and the liq. 2 having absorbed and dissolved O2 is discharged 19 into the chamber 20. The pressure of the liq. contg. a large amt. of gaseous O2 is decreased in the chamber 20, and gaseous O2 is separated from the liq. 2 and discharged. Meanwhile, the greater part of O2 is liberated from the liq. 21, and the liq. 21 is again sent into the chamber 1, and a closed loop of the circulating liq. is formed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing oxygen-enriched air.

[Conventional technology]

Conventionally, a thin film with gas separation performance has been applied to the surface of a porous membrane, such as polysiloxane, polycarbonate, polyvinylpyridine, polyester! , cast method, water surface development method, etc.
Those formed by plasma polymerization or coating methods are used as gas separation membranes for producing oxygen-enriched air.

The performance of such a gas separation membrane is largely controlled by the properties of the formed thin film, and is also influenced by the properties of the porous membrane-like body of the substrate. Furthermore, in order to improve the durability of thin film adhesion to porous membranes, strict techniques are required to make the quality of the thin film uniform, such as plasma etching in various atmospheres when forming the thin film.

In addition, when applied, gas separation performance improves in proportion to Ganu pressure, but since the pressure resistance of these gas separation membranes themselves is limited, the area of the gas separation membrane is large compared to the amount of gas to be processed. Due to the need to reinforce pressure resistance, the module
has become more complex, leading to higher costs. In addition, when this type of gas separation membrane module becomes contaminated with various contaminants in the air, it is almost impossible to clean the membrane surface, making it necessary to replace the module itself.

Another method has been used in the past, in which oxygen is selectively adsorbed on a solid adsorbent such as a molecule sieve, and the adsorbed oxygen is desorbed and recovered using changes in heat or pressure. Generally, a method is adopted in which the cylinder performs adsorption and desorption functions alternately. However, even in this method, the apparatus must be stopped to replace the adsorbent, and there are also problems in that the power consumption is large and the oxygen production cost is high.

[Problem to be solved by the invention]

In view of the above-mentioned state of the art, the present invention seeks to provide a method for producing oxygen-enriched air that does not have the disadvantages encountered in the prior art described above.

[Means to solve the problem]

The present invention uses a liquid that selectively absorbs oxygen in the air, circulates the liquid in a closed circuit of a pressurizing chamber and a depressurizing chamber, and separates and recovers the dissolved and absorbed oxygen in the depressurizing chamber. This is a method for producing oxygen-enriched air.

[Effect]

This property can be seen in liquids that selectively adsorb oxygen and reversibly adsorb and desorb oxygen, such as Norikon oil, but in order to further improve the selectivity, it is necessary to
-Polysiloxane polymer containing a hissic base complex, or top ~) (n) -N,N'-bis(salicylidene)ethylenediamine complex, top μ) (I) -N
, N'-bis(salicylideneimino)di-n-propyμ
Examples include polysiloxane polymers containing amine complexes. By circulating a liquid with such characteristics in a closed furnace between an air pressurization chamber and a depressurization chamber, υ, Can be applied as an agent.

■ Even if contamination of the liquid adsorbent progresses, functional deterioration such as membrane contamination is unlikely to occur.

■ Replacing the liquid adsorbent requires stopping the equipment if the entire amount is replaced at once, but it is also easy to add new liquid while removing it little by little, making it possible to replace the liquid without stopping the equipment. .

■ In the gas fraction M membrane method, the oxygen separation capacity is evaluated in two-dimensional terms, such as the amount of oxygen passing through the membrane surface, and in the case of Molecu2Seep, the amount of oxygen adsorbed by the total surface area of the solid. Since it exhibits a three-dimensional separation ability for oxygen that is adsorbed and dissolved in the oxygen, the separation ability is extremely high, the equipment can be downsized, and the cost per amount of oxygen produced is low.

■ It is known as Henry's law that the amount of air dissolved in a liquid is proportional to the pressure, but the saturated solubility at that pressure varies depending on the type and composition of the liquid. The present invention uses a liquid that selectively adsorbs and dissolves oxygen in general air (about 20% oxygen and about 80% nitrogen), and it is easy to increase the oxygen concentration to 80% or more.

Further, it is also possible to obtain 9100% oxygen by multi-stage treatment or the like.

■ In a pressurized liquid, the finer the gas bubbles in the supplied gas, the more rapidly it will dissolve into the liquid. If the bubble diameter is 100μ or less, it will dissolve instantly. It is also effective to stir the gas-liquid mixture in a pressurized chamber in order to prevent bubbles from floating up.

When a gas-dissolved liquid is left standing under normal pressure or reduced pressure, it does not separate and foam, but when it is subjected to impact or disturbance, it foams and separates almost instantly, so it is also effective to install a jam plate, etc. in the vacuum chamber. It is.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is a pressurized chamber, and a liquid 2 having an oxygen absorption state is loaded therein. Compressor 3 from the bottom of the pressurized chamber
The air supplied by the diffuser 4 is released into the liquid 2 as microbubbles. The air is sucked into the supply air, impurities in the air are removed in advance by a filter 5, and moisture is removed by a dehumidifier 6 (on the other hand, the liquid 21 in the decompression chamber 20 is The liquid is sent from the liquid suction port 25 to the liquid feeding pump 8 through the check valve 9 to the pressurizing chamber 1 from the liquid dispersing port 10. Pressurizing chamber 1
When the pressure inside increases and the pressure gauge 11 indicates a predetermined pressure, the oxygen gas component in the fine bubbles released by the diffuser 4 is actively absorbed into the liquid 2, and the upper gas layer inside the pressurizing chamber 1 has an oxygen concentration. It is mainly nitrogen gas. Since the air supply from the compressor 5 and the liquid supply from the pump 8 proceed continuously, the pressure inside the pressurizing chamber 1 further increases and when the valve opening pressure is reached, the liquid discharge pulp 16 opens. ,
The needle μ bubble 17 has a mechanism that is displaced by the signal from the liquid level gauge 18, and the liquid 2 in which oxygen has been absorbed and dissolved is transferred from the pressure feed port 14 to the pipe 15, the pulp 16, and the needle μ pipe 1.
7 and is discharged from the ejection port 19 into the decompression chamber 20.

In this case, the liquid 2 dissolves a large amount of oxygen gas and reaches the needle pulp 17 in an almost transparent state, but when it passes through the valve 17, the pressure is relaxed, so rapid foaming occurs. Oxygen gas and liquid are released from the jet port 19 in a separated state. The liquid 21 loses most of its oxygen and is again pumped into the pressurizing chamber 1 through the suction port 25, forming a closed liquid circulation system.

The relief pulp 12 is adjusted to open when the pressure in the pressurization chamber 1 becomes slightly higher than the valve opening pressure, and the air with low oxygen concentration in the pressurization chamber 1 is discharged through the discharge port 13. released into the atmosphere.

On the other hand, the gas separated in the decompression chamber 20 is mainly oxygen gas, and passes through the droplet removal mechanism 22 for removing minute droplets generated during foaming and separation, and then enters the oxygen storage tank 30 through the exhaust port 24. Sent.

Liquid 2 and liquid 21 have the same composition, but liquid 2 is in an oxygen absorption state, and liquid 21 is in an oxygen desorption (release) state. When deterioration or contamination progresses when these liquids are used for a long period of time, the liquid discharge pulp 26 is opened and extracted, and new liquid is fed into the liquid supply pulp 27 to adjust the liquid level and renew the liquid. It can be done easily.

In addition, in the figure, 7, 7I and 7g indicate check valves.

〔Effect of the invention〕

The present invention eliminates the problems in the prior art, and the present invention can be used in the following applications: ■ Production of oxygen-enriched air applied to combustion equipment such as boilers, ■ Supply of breathing oxygen for hospitals, aviation, etc., and ■ Steel material production. It can be advantageously applied to supplying oxygen for cutting and welding, (1) producing oxygen for activated sludge treatment of urban sewage and general industrial wastewater, (2) producing oxygen for blowing steel into blast furnaces, converters, and open hearths.

[Brief explanation of drawings]

The figure is a system diagram for explaining one embodiment of the present invention. Akira

Claims (1)

[Claims] It is characterized by using a liquid that selectively absorbs oxygen in the air, circulating the liquid in a closed circuit of a pressurizing chamber and a decompression chamber, and separating and recovering the dissolved and absorbed oxygen in the decompression chamber by pressurizing the air. A method for producing oxygen-enriched air.