KR20050031597A - Method for purifying oxygen and apparatus thereof - Google Patents

Abstract

To provide an oxygen production method and an oxygen production apparatus capable of simplifying structure of the apparatus, obtaining a very high oxygen recovery ratio at low cost and effectively producing oxygen having 99.9% of high purity. A oxygen production method is provided by using a plurality of carbon molecular sieve beds in which an adsorbent for adsorbing oxygen only from air is embedded. The oxygen production method comprises: a first oxygen adsorption/production step in which oxygen is produced as pressure of a second carbon molecular sieve bed(200) is reduced to the atmospheric the pressure through number 6 and 12 valves when pressurization/relief and oxygen adsorption processes are performed in a first carbon molecular sieve bed(100) after blowing of a blower(B) is controlled by number 1,2,3 and 9 valves and flow rate/pressure control valves(30,40); a pressure equalization step in which impurities are discharged from the first carbon molecular sieve bed, and initial pressurization is conducted in the second carbon molecular sieve bed in a pressure equalization process of the first and second carbon molecular sieve beds through number 7 and 8 valves; and a second oxygen adsorption/production step in which when oxygen is produced as pressure of the first carbon molecular sieve bed is reduced to the atmospheric pressure through number 4 and 12 valves, blowing of the blower is controlled by number 1,2,5 and 10 valves and the flow rate/pressure control valves such that pressurization/relief and oxygen adsorption processes are performed in the second carbon molecular sieve bed.

Description

Oxygen Purification Method and Apparatus {METHOD FOR PURIFYING OXYGEN AND APPARATUS THEREOF}

The present invention relates to an oxygen production method and apparatus, and more particularly, to an oxygen production method and apparatus configured to produce 99.9% high purity oxygen at low cost and high efficiency by using two carbon molecular sieve towers. will be.

In general, as a method for separating and producing oxygen from air, there is an absorption method in which oxygen, nitrogen, argon, and other elements in the air are absorbed by a specific liquid and separated. Adsorption methods for allowing the elements in to be selectively adsorbed and separated, and deep cooling method for rapidly reducing the temperature of the gas at room temperature to make a liquid and to separate the oxygen through distillation.

However, the absorption method has a problem of preparing a large amount of absorption liquid when a large amount of oxygen is to be produced, and it is very difficult to absorb individual elements in the air in the liquid, and also takes a long time for absorption. There is a problem.

In addition, since the deep cooling method must include both a large-sized cooling device for rapidly cooling air and a large-sized distillation device for distilling the cooled air, there is a problem in that excessive investment costs are caused by the purchase and installation of the device.

Of course, the deep cooling method is more expensive than the above-described absorption method and adsorption method, while the advantage of producing oxygen with a purity of 99% or more is preferred, but due to the large size and excessive investment of the device, It is not possible to install.

Therefore, at present, an adsorption method is mainly used in which elements are separated using solids having micropores corresponding to the bulk of specific elements in the air.

Zeolite is mainly used as an adsorbent in the adsorption method, because zeolite acts as a strong adsorbent for nitrogen and a weak adsorbent for oxygen.

Therefore, when air is supplied to the zeolite, nitrogen is adsorbed to the zeolite and oxygen is permeated and discharged, thereby producing oxygen that is significantly excluded from the nitrogen. At this time, the produced oxygen has an adsorption capacity similar to that of a small amount of nitrogen and oxygen not removed from the zeolite. It contains argon that is not adsorbed.

Therefore, the oxygen production system by the general adsorption method is composed of a zeolite tower filled with a zeolite inside, there is also a system in which the zeolite tower is composed of double or triple to increase the purity of the oxygen produced in some cases.

However, the oxygen produced by this adsorption oxygen production system is only up to 95% of the purity of oxygen due to the difficulty of argon separation, and oxygen producers have been using this system since the 1980s to obtain more than 99% high purity oxygen. We are developing a process for production.

Currently, the US BOC and Crew Technology Division Amstrong Raboratory and Japan's Sumitomo Seike Co., Ltd. are leading the field, and the companies will soon commercialize systems capable of producing 99.7% high purity oxygen. to be.

However, the oxygen production system of these companies is composed of adsorption process for bulk separation and adsorption process for purification, so it is necessary to complete the adsorption process for bulk separation and perform the adsorption process for purification again. Due to the high production cost of oxygen is the biggest problem.

On the other hand, it is also possible to produce high-purity nitrogen by the adsorption method, in which case CMS (Carbon molecular sieve) is used as the adsorbent, because the oxygen in the CMS dozens to hundreds times faster than nitrogen or argon This is because it is adsorbed by.

That is, due to the difference in the adsorption rate of oxygen and nitrogen and argon to the CMS, oxygen is quickly adsorbed to the CMS, while nitrogen and argon are not adsorbed and permeate the CMS to produce high purity nitrogen.

Such a nitrogen production system using CMS is usually composed of a CMS tower filled with CMS, CMS tower can also be configured as a double or triple tower to increase the purity and production of nitrogen produced.

On the other hand, recently, the zeolite tower system described above produces 90-95% of oxygen containing impurities such as nitrogen and argon, and then purifies the oxygen with the aforementioned CMS tower system to produce more than 99% of oxygen. The process was developed.

However, this process is a simple multi-stage system that operates independently because the zeolite tower system and the CMS tower system are separately operated. Therefore, not only each system should be equipped, but also the dual operation cost and the double energy cost due to individual independent operation. Since the raw material has to go through each individual system, the recovery rate of oxygen is sharply lowered.

In particular, when oxygen is produced in a deep cooling method for air separation, an oxygen-containing adsorbent in ultra low temperature state is produced in order to have a purity of 99.8% or more after primarily producing oxygen containing impurities such as trace amounts of nitrogen and argon. It is necessary to go through the adsorption process again.

However, such a separate purification process requires a high energy cost because it operates in an ultra-low temperature state, which eventually increases the production cost of oxygen.

The present invention has been made to improve such a conventional problem, the pressure equalization process while alternately performing the oxygen adsorption process by the pressure or the oxygen production process by reduced pressure to the two carbon molecular sieve bed (Carbon Molecular Sieve Bed) By purifying high-purity oxygen and producing it through the structure, the structure is simple and the recovery rate of oxygen is very high even at low cost, and it provides an oxygen production method and apparatus that can effectively produce high purity oxygen of 99.9%. The purpose is.

In order to achieve the above object, the present invention provides a method for producing oxygen using a plurality of carbon molecular sieve towers in which an adsorbent adsorbs only oxygen in the air, and the blower blows the valves 1,2,3,9 and flow rate / pressure. When controlled by a control valve and pressurized / discharged and oxygen adsorption is performed in the first carbon molecular tower, the second carbon molecular tower is decompressed to atmospheric pressure through valves 6 and 12 to produce oxygen while producing oxygen. Steps; A pressure equalization step in which the first carbon molecular sieve discharges impurities and the second carbon molecular sieve tower has an initial pressure in the pressure equalization process of the first carbon molecular sieve tower and the second carbon molecular sieve tower through valves 7,8; When oxygen is produced while the pressure is reduced to atmospheric pressure through the valves 4 and 12 in the first carbon molecular tower, the blower of the blower is controlled by the valves 1,2,5,10 and the flow rate / pressure control valve, so that the second carbon molecular sieve It provides a method for producing oxygen, characterized in that consisting of; a second oxygen adsorption / production step in which the pressure / discharge and oxygen adsorption process is performed in the tower.

In addition, the present invention is an oxygen production apparatus using a plurality of carbon molecular sieve towers containing an adsorbent adsorbing only oxygen in the air, the oxygen adsorption process by pressure in the first and second carbon molecular sieve tower, and the oxygen production process by reduced pressure It is configured to be carried out alternately, through the pressure equalization process to provide an oxygen production apparatus characterized in that the first and second carbon molecular sieve purification by the reduced pressure and the initial pressure is configured to be respectively.

1 is a block diagram illustrating an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to an embodiment of the present invention, as shown in FIG. 1, a first and second carbon molecular sieve bed (100,200) having an adsorbent for selecting and adsorbing only oxygen from the air supplied to the inside is adsorbed. To control the pressurization, depressurization, and pressure equalization processes of the flow control valve 30 and the pressure control valve 40 maintaining the internal pressure of the first and second carbon molecular sieves and the first carbon molecular sieve or the second carbon molecular sieve. It consists of a plurality of solenoid valves (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12).

Hereinafter will be described in detail the configuration and operation of the present invention through the oxygen production process of the present invention.

In the first oxygen adsorption / production step, for example, while the first carbon molecular sieve 100 is subjected to an oxygen adsorption process while being pressurized by air supplied from the blower B, the second carbon molecular sieve 200 is decompressed to atmospheric pressure. It is configured to produce high purity oxygen.

First, suppose that the first oxygen adsorption / production stage in which the first carbon molecular sieve 100 is pressurized to a constant pressure and the second zeolite tower 200 is controlled to be reduced to atmospheric pressure is supplied by the blower B. Air of a predetermined pressure is supplied to the first carbon molecular sieve 100 through the open valve 1 and the valve 3, the first carbon molecular sieve 100 is pressurized to a predetermined pressure by the air supplied to the inside In this pressurized state, the built-in adsorbent is used to selectively adsorb oxygen in the air.

Then, when the internal pressure of the first carbon molecular sieve 100 reaches a predetermined pressure, instead of closing the valve 1, valves 2, 9, and 11 are opened, and the flow control valve 30 is a blower. The flow rate of the air supplied to the first carbon molecular sieve 100 from (B) is constantly adjusted.

In addition, the air in the first carbon molecular sieve 100 is discharged to the outside through the open valve 9, the pressure control valve 40 is the pressure of the first carbon molecular sieve 100 in the air discharge process The control is to be kept constant.

In particular, the air discharged through the open valve 9 has a significantly lower oxygen concentration than the air supplied from the blower (B), which is caused by the adsorbent in the tower during the first carbon molecular sieve 100. This is because oxygen is adsorbed and the concentration of impurities such as nitrogen and argon is relatively high.

At this time, while the first carbon molecular sieve 100 undergoes a process of pressurization and oxygen adsorption, the second carbon molecular sieve 200 receives a reduced pressure to atmospheric pressure through valves 6 and 12 opened. In the case of the oxygen production operation, the oxygen adsorbed by the adsorbent inside is discharged to the outside to produce high purity oxygen of 99.9%, but the first oxygen production operation is stopped under the reduced pressure.

On the other hand, the pressure equalization step is to equalize the pressure in the first carbon molecular sieve 100 and the second carbon molecular sieve 200 in a state in which only valves 7 and 8 are opened, and the first pressure is relatively high. Although the carbon molecular sieve tower 100 is decompressed, the second carbon molecular sieve tower 200 in a relatively low pressure state is pressurized.

Here, in the pressure equalization step, the first carbon molecular sieve 100 discharges the internal pressure to the second carbon molecular sieve 200 until the pressure between the two towers is the same through the open valve 7 and valve 8. In this case, impurities such as nitrogen and argon in the air in the first carbon molecular sieve are mainly discharged during the pressure discharge process.

As a result, when the pressure equalization step is performed, the first carbon molecular sieve 100 reduces the pressure to a predetermined pressure and discharges impurities such as nitrogen and argon remaining therein to the second carbon molecular sieve 200. It has oxygen of 99.9% purity.

On the other hand, in the second carbon molecular sieve 200 through the pressure equalization step, the initial pressurization is performed to a predetermined pressure by the pressure supplied from the first carbon molecular sieve tower, thereby significantly reducing the pressurization time by the blower (B). Will be.

In the second oxygen adsorption / production step, the air of a predetermined atmospheric pressure supplied by the blower B is supplied to the second carbon molecular sieve tower 200 through the first valve and the fifth valve which are opened, and in the pressure equalization step, In the second carbon molecular sieve 200, which is in the initial pressurized state, it is pressurized within a shorter time to a predetermined pressure by the air supplied therein to selectively adsorb oxygen in the air by using the built-in adsorbent in this pressurized state. .

When the internal pressure of the second carbon molecular tower 200 reaches a predetermined pressure, instead of closing the valve 1, the valve 2, the valve 10, and the valve 11 are opened, and the flow control valve 30 is a blower. The flow rate of the air supplied to the second carbon molecular sieve 200 from (B) is constantly adjusted.

In addition, through the open valve 10, the air in the second carbon molecular sieve 200 is discharged to the outside, wherein the pressure control valve 40 is the pressure of the second carbon molecular sieve 200 in the air discharge process The control is to be kept constant.

In particular, the air discharged through the open valve 10 has a significantly lower oxygen concentration than the air supplied from the blower (B), which is caused by the adsorbent inside the tower during the second carbon molecular sieve 200. This is because oxygen is adsorbed and the concentration of impurities such as nitrogen and argon is relatively high.

At this time, while undergoing a process of pressurization and oxygen adsorption in the second carbon molecular tower 200, the first carbon molecular sieve 100 is decompressed to atmospheric pressure through the open valve 4 and valve 12, As the oxygen adsorbed by the adsorbent inside is discharged to the outside through the decompression process, high purity oxygen of 99.9% is produced.

In the pressure equalization step of equalizing the pressure in the first and second carbon molecular sieves 100 and 200, the second carbon molecular sieve 200 having a relatively high pressure in the state where only the seventh and eighth valves are opened is decompressed. Although this is made, the first carbon molecular sieve 100 in a relatively low pressure state is made to be pressurized.

Here, the second carbon molecular sieve tower 200 discharges the pressure inside the first carbon molecular sieve tower 100 until the internal pressure between the two towers is the same through the seventh valve and the eighth valve which are opened. In the pressure discharge process, impurities such as nitrogen and argon in the air in the second carbon molecular sieve are mainly discharged.

As a result, when the pressure equalization step is performed, the second carbon molecular sieve 200 depressurizes to a predetermined pressure and discharges impurities such as nitrogen and argon remaining therein to the first carbon sieve 100 to discharge the inside thereof. It has oxygen of 99.9% purity.

On the other hand, during the pressure equalization step, the first carbon molecular sieve 100 receives initial pressure up to a predetermined pressure by the pressure supplied from the second carbon molecular sieve 200, thereby increasing the pressurization time by the blower B. Can be significantly reduced.

As described above, in the present invention, after purifying high-purity oxygen through a pressure equalization process while alternately performing a pressurization process or a depressurization process for the first carbon molecular sieve 100 and the second carbon molecular sieve 200, it can be produced. It is configured to have the technical characteristics.

On the other hand, one cycle of the oxygen production operation according to the present invention can be represented simply as Table 1 below.

Table 1.

  Oxygen adsorption / production stage  Pressure equalization stage Oxygen adsorption / production stage Pressure equalization stage First Carbon Molecular Tower Pressurization Process Oxygen adsorption process / impurity discharge process Pressure Equalization Process of Pressure Reduction Oxygen Production Process by Decompression Pressure equalization process of pressurization 2nd carbon molecular sieve tower Oxygen Production Process by Decompression Pressure equalization process of pressurization Pressurization Process Oxygen adsorption process / impurity discharge process Pressure Equalization Process of Pressure Reduction

As described above, specific embodiments have been described in the detailed description of the present invention, but various modifications may be made without departing from the scope of the present invention.

Therefore, the substantial scope of the present invention should not be limited by the above-described embodiment, but should be defined by the same structure as the claims as well as the claims described below.

The present invention constituted as described above provides the effect that the structure is simple and the recovery rate of oxygen is very high even at low cost, and it is possible to effectively produce high purity oxygen of 99.9%.

1 is a block diagram illustrating an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1,2,3,4,5,6,7,8,9,11,12: Solenoid Valve 30: Flow Control Valve 40: Pressure Control Valve 100: First Carbon Molecular Tower 200: Second Carbon Molecular Tower B: air blower

Claims (2)

In the oxygen production method using a plurality of carbon molecular sieve column containing an adsorbent adsorbing only oxygen in the air, When the blower of the blower (B) is controlled by the valves 1,2,3,9 and the flow rate / pressure control valves 30,40 to pressurize / discharge and oxygen adsorption process in the first carbon molecular sieve 100 The second carbon molecular sieve 200 includes a first oxygen adsorption / producing step of producing oxygen while reducing the pressure to atmospheric pressure through valves 6 and 12; In the pressure equalization process of the first carbon molecular sieve 100 and the second carbon molecular sieve 200 through valves 7, 8, the first carbon molecular sieve 100 discharges impurities, and the second carbon molecular sieve tower ( 200) is the pressure equalization step of the initial pressure is made; When the oxygen is produced while the pressure is reduced to atmospheric pressure through the valves 4, 12 in the first carbon molecular sieve 100, the blower B blows the valves 1,2, 5, 10 and the flow / pressure control valve 30 And a second oxygen adsorption / producing step of controlling the pressure by the second carbon molecular sieve 200 and the oxygen adsorption step is performed by the second carbon molecular sieve 200. In the oxygen production apparatus using a plurality of carbon molecular sieve column containing an adsorbent that adsorbs only oxygen in the air, The oxygen adsorption process by pressurization and the oxygen production process by pressure reduction are alternately performed in the first and second carbon molecular weight towers 100 and 200, but the pressure is reduced in the first and second carbon molecular weight towers 100 and 200 through a pressure equalization process. Oxygen production apparatus, characterized in that configured to be made by the oxygen purification and the initial pressure.