JPH11292511A - Production of oxygen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of efficiently producing oxygen in which barium oxide is heated in air to form barium peroxide, which is reheated after deaeration to be decomposed to produce oxygen. SOLUTION: In the method in which the barium oxide is oxidized under air circulation to produce the barium peroxide, then the barium peroxide is decomposed to produce oxygen, an oxidation column 5 in which the oxidation is executed and an oxygen generating column 6 in which the decomposition is executed are provided, and the barium oxide is supported on a porous metal oxide particle carrier and the carrier is circulated between the oxidation column and the oxygen generating column.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for oxidizing a metal oxide mainly composed of barium oxide in a flow of air and then decomposing the obtained metal oxide mainly composed of barium peroxide to recover oxygen. Thereby producing oxygen from air.

[0002]

2. Description of the Related Art Hitherto, several methods and apparatuses for producing oxygen using barium oxide are known.

For example, at the end of the 19th century, Brin Proc
There is a method implemented as ess. This method
A lump of barium oxide is filled in a cast iron retort, and air is flowed through the retort at a temperature of 550 to 650 ° C. and a pressure of 1.5 to 2 atm to oxidize barium oxide to barium peroxide. It exhausts at a temperature of 800 to 900 ° C. and a pressure of 0.05 to 0.15 atm to decompose barium peroxide and recover oxygen.

Further, Japanese Patent Application Laid-Open No. 47-4962 discloses that
A horizontal wire mesh is placed in a rectangular reactor, and granular barium oxide is arranged on the wire mesh. Compressed air is passed through the barium oxide at a temperature of 650 to 760 ° C to oxidize the barium oxide, and then the pressure is increased. An apparatus for producing oxygen from air is disclosed which recovers oxygen by returning to atmospheric pressure and degassing with a vacuum pump.

Further, US Pat. No. 3,310,381 discloses that barium oxide is oxidized by flowing air through an oxidizer under the conditions of 500 to 720 ° C. and 1 to 4 atm. The mixture slurry of barium oxide is sent to an oxygen separator, and then the oxygen separator is used at 700-800 ° C. for 0.1 hour.
Disclosed is a method for producing oxygen, in which a mixture slurry of barium oxide and barium peroxide, which is decomposed under a pressure of １1 atm, is repeatedly sent to an oxidizer.

[0006]

SUMMARY OF THE INVENTION However, Bri
In the process for producing oxygen by n Process,
As a method for heating the massive barium oxide and barium peroxide particles, a method of heating a cast iron retort from outside with hot air is employed. However, since barium oxide and barium peroxide have poor thermal conductivity, heat transfer to barium oxide and barium peroxide particles is not performed well,
In particular, the temperature required for the decomposition reaction of barium peroxide, which is an endothermic reaction, cannot be secured. Therefore, there are problems such as a low decomposition rate of barium peroxide and an insufficient oxygen recovery rate.

[0007] In the oxygen production apparatus described in Japanese Patent Application Laid-Open No. 47-4962, granular barium oxide is liable to fall off the wire mesh. Further, the granular barium oxide increased in proportion to the barium peroxide with the progress of the oxidation reaction and gradually melted, so that the melt adhered to the wire mesh. This has caused problems such as obstruction of the wire net, making air circulation difficult.

In the method for producing oxygen described in US Pat. No. 3,310,381, the barium oxide concentration in the barium oxide-barium peroxide mixture slurry discharged from the oxygen separator is 14%. The barium oxide-barium peroxide mixture slurry discharged from the oxidizer has a barium oxide concentration of 7%. That is, only 7% of the mixture slurry of barium oxide and barium peroxide circulating between the oxidizer and the oxygen separator actually participates in the oxidation reaction and the decomposition reaction, and is therefore extremely inefficient. Met. Further, the slurry of the barium oxide-barium peroxide mixture has a high viscosity.
In order to circulate at a temperature of about 00 ° C., there is a problem that a very special and expensive circulation pump is required.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, previously formed barium oxide on a porous metal oxide particle carrier to form a moving bed medium. The present inventors have found that the above problem can be solved by moving a moving medium between an oxidation tower and an oxygen generation tower and performing barium oxide oxidation and decomposition reactions in each reaction tower.

That is, the present invention provides a method for producing barium peroxide by oxidizing barium oxide under air flow, and then decomposing the barium peroxide to generate oxygen. And an oxygen generating tower for performing the decomposition, wherein barium oxide is supported on a porous metal oxide particle carrier, and this is circulated between the oxidizing tower and the oxygen generating tower. Is provided.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The metal oxide particle carrier used in the present invention needs to have heat resistance and has a melting point of at least 800.
° C or higher, preferably 900 ° C or higher, particularly preferably 10 ° C or higher.
More than 00 ° C. Further, those having high physical strength and abrasion resistance are preferable. From these requirements, those belonging to ceramics are preferable, and specifically, alumina,
Examples include silica, silica alumina, titania, zirconia, and magnesia. The specific surface area of the porous metal oxide particle carrier measured by the BET method is 50 m ² / g or more,
Particularly, those having 100 m ² / g or more are preferable. The size of these metal oxide particles is not particularly limited, but is preferably about 1 to 10 mm in diameter for transferring between reaction towers.

The amount of barium oxide supported on the metal oxide particle carrier is not particularly limited, but the molar ratio of barium oxide to the metal oxide particle carrier is reduced in view of making the reaction tower compact and improving thermal efficiency. From 10:90 to 50:50
The degree is preferred. The loading method is performed by a general catalyst preparation method such as a dry-dry method, an adsorption method, a dry impregnation method, and a spray method.

The size and shape of the oxidation tower and oxygen generating tower are not particularly limited, but the size is determined by the scale of oxygen production. The material is not particularly limited as long as it can withstand a temperature of about 800 ° C.
S is preferred. Heat is supplied to the reaction tower by external heat such as a heat exchange method using a heat medium such as steam or carbonate, or a direct heating method using fuel combustion heat.

The transport of the barium oxide-supported metal oxide particles between the oxidation tower and the oxygen generation tower is not particularly limited, but a method using an air transport device is generally used.

First, in the oxidation step, air serving as an oxidation source is supplied to an oxidation tower after removing carbon dioxide, water vapor and dust by a standard air purifier in advance. on the other hand,
The group of metal oxide particles carrying barium oxide is transported from the oxygen generation tower by a pneumatic transport device and supplied to the oxidation tower. In the oxidation tower, barium oxide in the particle group is oxidized to barium peroxide. Next, the particle group is discharged from the oxidation tower and supplied to the oxygen generation tower by the pneumatic transport device. In the oxygen generation tower, barium peroxide in the particle group is decomposed, and oxygen is recovered.

The oxidation reaction of barium oxide in the reaction tower is performed at a temperature of 400 to 700 ° C. and a pressure of 2 to 10 atm. The supply amount of air is 1 k of barium oxide and barium peroxide in total.
The range is from 2 to 10 Nm ³ per hour per g.

In the decomposition reaction of barium peroxide in the oxygen generating tower, the reaction temperature is in the range of 500 to 800 ° C., and the reaction pressure is in the range of 0.1 to 1.0 atm.

[0018]

Next, the present invention will be described specifically with reference to examples.

Barium oxide was previously loaded on alumina pellets having a diameter of 5 mm at a weight ratio of 20% to the pellets to form a moving bed medium.

[Preparation of Oxygen Absorbent] Barium hydroxide (Ba (OH) ₂ .H ₂ O) was charged into a kneader, and kneaded while gradually adding water thereto. Subsequently, 15 kg of alumina pellets having a particle size of 3 mm were charged and impregnated with an aqueous barium hydroxide solution. Next, this molded product was dried in a nitrogen stream at a temperature of 120 ° C. for 24 hours, and further fired in a nitrogen stream at a temperature of 600 ° C. for 3 hours to obtain a target oxygen absorbent. The composition of the obtained oxygen absorbent was BaO: Al ₂ O ₃ = 50: 50 (weight ratio).

FIG. 1 shows an embodiment of an apparatus for implementing the present invention. First, in the oxidation step, the air supplied through the air conduit 1 is pressurized by the air compressor 2 and introduced into the air purification device 3. The air from which carbon dioxide gas, water vapor and dust have been removed by the air purification device 3 is heat-exchanged with the product oxygen discharged from the oxygen generation tower 6 by the heat exchanger 4 and is preheated to the oxidation tower 5.
Supplied to On the other hand, the moving bed medium is transferred from the oxygen generation tower 6 and supplied to the oxidation tower 5. The heating medium heated in the heating furnace 10 for the oxidation reaction is introduced into the oxidation tower 5 by the heating medium pump 11. In the oxidation tower 5, the moving bed medium has a temperature of 5 ° C.
The barium oxide in the medium is oxidized under conditions of 00 to 650 ° C. and a pressure of 1 to 5 atm to barium peroxide. The waste air discharged from the oxidation tower 5 passes through the switching valve 7,
The heat is exchanged with the air for the raw material in the heat exchanger 4, the heat is exchanged with the water vapor in the heat exchanger 8, the heat is cooled, and discharged from the waste air conduit 9. The moving bed medium that has become barium peroxide is discharged from the lower part of the oxidation tower and supplied to the oxygen generation tower 6.

Next, in the decomposition step, the heat medium heated in the heat medium heating furnace 16 for decomposition is introduced into the oxygen generation tower 6 by the heat medium pump 15. The supplied moving bed medium is decomposed in the oxygen generating tower 6 at a temperature of 750 to 900 ° C. and a pressure of 0.1 to 1 atm, and barium peroxide in the moving bed medium is reduced to barium oxide to generate oxygen. I do. Oxygen generated in the oxygen generating tower 6 is recovered by the oxygen blower 12 from the oxygen generating tower 6 via the heat exchanger 13 through the oxygen conduit 14, while the moving bed medium is transferred and supplied to the oxidation tower 5 again.

The above-described oxidation step and decomposition step are repeated at regular time intervals.

[Reaction and Result] The above oxygen absorbent 25k
g was used as the moving bed medium. 10 Nm ³ / h of air from which carbon dioxide and water vapor had been removed in advance was introduced into the oxidation tower. Then, the moving bed medium was transferred to the oxidation tower,
The oxidation reaction of the barium oxide component in the moving bed medium was performed under the conditions of 00 ° C. and a pressure of 5 kg / cm ² -G. After discharging the waste air, the moving bed medium was transferred to the oxygen generating tower. Next, a decomposition reaction of the produced barium peroxide component in the moving bed medium was performed in the oxygen generating tower under the conditions of a temperature of 750 ° C. and a pressure of 380 mmHg.

As a result of repeating the above oxidation reaction and decomposition reaction, the amount of generated oxygen was about 2 Nm ³ / h, and the purity of oxygen was almost 100%.

[0026]

As described above, according to the present invention, a moving bed medium is formed by previously supporting barium oxide on a porous metal oxide particle carrier, and the moving medium is transferred between an oxidation tower and an oxygen generation tower. The barium oxide is oxidized and decomposed in each reaction tower, reducing the reaction surface area due to melting and fusing of the reaction medium and reducing blockage trouble due to sticking to the reaction tower and piping. It is planned. Furthermore, the heat loss can be reduced by using two reaction towers,
It has a remarkable effect such as a low calorific value per unit and an improvement in oxygen recovery efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a method for producing oxygen of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air duct 2 Air compressor 3 Air purification device 4 Heat exchanger 5 Oxidation tower 6 Oxygen generation tower 7 Switching valve 8 Heat exchanger 9 Waste air duct 10 Heating medium heating furnace for oxidation reaction 11 Heat medium pump 12 Oxygen blower DESCRIPTION OF SYMBOLS 13 Heat exchanger 14 Oxygen conduit 15 Heat medium heating furnace 16 Heat medium heating furnace for decomposition reaction 17 Reaction tube 18 Fin 19 Metal oxide coating layer

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takashi Anyashiki 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (1)

[Claims] 1. A method for oxidizing barium oxide in a stream of air to produce barium peroxide, and then decomposing the barium peroxide to generate oxygen, comprising: an oxidation tower for performing the oxidation; A method for producing oxygen, comprising: providing an oxygen generating tower to be performed, supporting barium oxide on a porous metal oxide particle carrier, and circulating this between the oxidation tower and the oxygen generating tower.