JPH10249131A - Adsorber, pressure swing adsorption separator, and gas separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a simple inexpensive adsorber by forming a shell of an adsorber packed with an adsorbent suitably used in an air separation plant for separating air into oxygen and nitrogen by an adsorption method of a flexible material. SOLUTION: This adsorber 1 has a shell 3 made of a flexible material having the performance of gas cutoff packed with an adsorbent and if necessary, other packings, and it is constituted so that pressure (external pressure) applied on the adsorber 1 by the atmosphere is received by the adsorbent 2 through the shell 3. The shell 3 is provided in both the lower and upper end parts with connecting pipes (nozzles) 4, 5 which become a gas inlet and a gas outlet respective. As a material for the shell 3, nylon, polyethylene, polyvinyl chloride or the like is cited. The adorbent 2 is formed into sphere, cylinder cube, rectangular or the like in advance to make it an adsorbent formed material having a prescribed shape, and the outer surface thereof is covered with a gastight treating material (a sealant) to make it the shell 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption tower, a pressure fluctuation adsorption separation apparatus and a gas separation method, for example, an adsorption tower used in an air separation apparatus for separating oxygen and nitrogen in air by an adsorption method, and The present invention relates to an adsorption / separation apparatus using the adsorption tower and an operation method of the adsorption / separation apparatus.

[0002]

2. Description of the Related Art As a method for separating an industrial gas using an adsorbent, a pressure fluctuation adsorption separation method (Pressure S) is used.
A method called wing Adsorption method (hereinafter abbreviated as PSA method) is widely known. This P
Although there are various types of SA methods depending on the process, there is a method called a vacuum regeneration pressure fluctuation adsorption separation method in which regeneration is performed under reduced pressure (hereinafter abbreviated as VPSA method). VPS
In the method A, generally, a plurality of adsorption towers are installed, and for these adsorption towers, adsorption, pressure reduction, vacuum regeneration, purge regeneration,
The gas is continuously separated by repeating the steps of equalizing pressurization and pressurization sequentially. In the adsorption step, a raw material gas (for example, air) is supplied to the adsorption tower with a blower or the like, and the pressure in the adsorption step is slightly higher than the atmospheric pressure. The pressure in the regeneration step is generally about 150 to 250 mmHg.

[0003] The container for filling the adsorbent is made of steel, stainless steel, or other thick metal material to withstand the external pressure (atmospheric pressure) in the vacuum regeneration or purge regeneration process. The shape is usually a vertical type, and a large type is a horizontal type or a spherical type.

[0004]

The container for filling the adsorbent of the conventional VPSA method is usually formed in a cylindrical or spherical shape so that the container itself can withstand and receive an external pressure (atmospheric pressure). I have. In each case, the thickness of the container is increased and the weight of the container is increased. In the case of a large-sized device, the basic equipment is inevitably strict, and the cost of the entire device is increased.

Accordingly, an object of the present invention is to provide an adsorption tower, a pressure fluctuation adsorption / separation apparatus and a gas separation method capable of obtaining a simple and low-cost adsorption tower and reducing the equipment cost.

[0006]

In order to achieve the above object, an adsorption tower according to the present invention is characterized in that the outer shell of the adsorption tower is formed of a flexible material. Further, the adsorption tower of the present invention has a structure in which an external pressure applied to the outer shell is received by an adsorbent inside the tower. Further, the outer surface of the adsorbent formed into a predetermined shape is coated with an airtight treatment material to form an outer shell, and the adsorbent is formed in a tower shape in advance. Further, a seal portion for sealing a connection portion of the gas inlet and outlet of the adsorption tower with the gas after the adsorption treatment is provided.

[0007] The pressure fluctuation adsorption separation apparatus of the present invention is characterized by using the adsorption tower having the above structure.
In the gas separation method, the gas is separated using the adsorption tower having the above configuration. In particular, in the gas separation method, the regeneration of the adsorbent in the adsorption tower is performed by a vacuum regeneration method, and further, in performing the separation of the gas by the pressure fluctuation adsorption separation method, the operating pressure of all the steps is set to an atmospheric pressure or less It is characterized by performing in.

[0008]

FIG. 1 is a partial sectional view showing an example of an adsorption tower according to the present invention. The adsorption tower 1 comprises an adsorbent 2 and other packing materials used as necessary. The outer shell 3 made of a flexible (flexible) material capable of blocking gas, for example, various resins and rubbers, is filled. The outer shell 3 has a role of a container containing the adsorbent 2, and the pressure (external pressure) applied to the adsorption tower 1 by the atmosphere is:
The structure is such that the adsorbent 2 receives through the flexible outer shell 3. In addition, connection pipes (nozzles) 4 and 5 serving as a gas inlet and a gas outlet are provided at upper and lower ends of the outer shell 3 respectively.

The performance of blocking the gas in the outer shell 3 may be such that the purity of the product gas is not practically reduced. Further, the strength or flexibility of the outer shell 3 withstands a difference between the atmospheric pressure and the pressure in the adsorption step and a difference between the atmospheric pressure and the pressure in the regeneration step when the adsorbent 2 is filled, and What is necessary is just to be able to withstand the state where the outer shell 3 is pressed against the adsorbent 2 by the atmospheric pressure. Materials that can be used for the outer shell 3 include nylon, polyethylene, polyvinyl chloride, polypropylene, polyethylene terephthalate, polycarbonate, fluororesin, polyurethane, natural rubber, butadiene rubber, styrene butadiene rubber, isobutylene isoprene rubber, nitrile butadiene rubber, and chloroprene rubber. , Polysulfide rubber, chlorinated polyethylene, silicon rubber,
Examples thereof include urethane rubber and fluorine rubber.

As shown in FIG. 2, the adsorbent 2 is previously formed into a spherical, cylindrical, cubic, or rectangular parallelepiped shape to form an adsorbent molded product 2a having a predetermined shape. 6) to form an outer shell. As the sealing material 6, any material can be used as long as a predetermined airtightness and strength can be obtained, and any material such as a liquid, a paste, a film, a sheet, and a tape can be used. is there.

Further, as shown in FIG. 3, after the outer surface of the adsorbent molded product 2a is covered with the sealing material 6 as described above, a cloth, a plastic sheet, a thin metal plate or the like is placed on the sealing material 6. Can be coated with the coating material 7. The coating material 7 mainly contributes to improvement in strength and durability.
The covering operation of the sealing material 6 and the covering material 7 can be performed by an appropriate method such as coating, sticking, and winding according to the form of each material. In addition, the sealing material 6 and the coating material 7 can be used in combination of a plurality of types according to their properties and forms, and the same material as the coating material 7 can be disposed inside the sealing material 6. For example, a cloth bag may be filled with an adsorbent, and a sealing material may be applied to the outer surface of the bag. Also, an appropriate reinforcing material can be used.

As the adsorbent 2, commercially available pellets having a diameter of about 2 mm and a length of about 5 mm, or spheres having a diameter of about several mm can be used. However, especially when applied to a large-sized apparatus, an adsorbent integrally formed in the shape of the adsorption tower can be used in order to increase the stability or strength of the adsorption tower. In addition, cubic or rectangular parallelepipeds having a side of several cm or several hundred cm, or cylinders, disks or spheres of this size, and molded adsorbents such as half-cut and quarter-cut products are produced and laminated. By combining or combining them, a large adsorption tower can be formed.

Further, an outer shell container made of the above-mentioned flexible material is filled with an adsorbent in a shape that does not hinder the flow of gas, and a plurality of the adsorbents are stacked to constitute one adsorption tower. You can also. This makes it possible to configure a strong and stable large adsorption tower even if the adsorbent has a relatively small shape.

Further, by connecting a plurality of adsorption towers whose outer shell containing the adsorbent is formed of a flexible material in series, in parallel, or in both directions, an adsorption tower having a larger function can be obtained. Can be configured.

As described above, by combining adsorbents of various shapes or units of adsorption towers, it is possible to easily manufacture an integrated adsorption tower and to increase strength and stability.

The nozzles 4 and 5 are provided with a wire mesh 8 for holding the adsorbent 2 and the like in the tower, according to the type of the flexible material and the sealing material constituting the outer shell 3. Depending on the connection method, the main body of the adsorption tower and the short pipes 4a, 5a constituting the nozzles 4, 5 are connected.

When other fillers such as ceramic balls are filled to fill gaps formed in the adsorption tower, the ceramic balls and the adsorbent are not mixed with each other.
A partition can be inserted between the adsorbent and the adsorbent as needed, but a part or all of the ceramic balls or the adsorbent may be filled in a bag having good air permeability.

To manufacture such an adsorption tower, the outer shell to which one of the nozzles is attached is held in a cylindrical or square mold, and the adsorbent or packing is packed. When the packing is completed, the other nozzle is attached. What should I do? Furthermore, the outer shell and the adsorbent can be integrated by closing one nozzle and exhausting air from the other nozzle, and pressing the outer shell against the adsorbent by atmospheric pressure.

If necessary, a distributor made of metal or a material that can withstand external pressure can be attached to improve gas dispersion. A compound or an adhesive can be used for the treatment of the end of the outer shell after the nozzle or the distributor is attached, if necessary.

If a gap is formed in the connection portion of the gas inlet / outlet end of the adsorption tower due to the relationship between the shape of the outer shell and the shape of the adsorbent, the space for the purpose of filling that portion or the cross section of the gas passing through the adsorption tower. For the purpose of uniformity, a gas-permeable block which does not hinder the gas flow may be provided in the adsorbent layer or at both ends to receive a part of the external pressure.

Further, as shown in FIG. 4, the gas inlet / outlet nozzle connection portion has a double wall structure to form a seal portion 9,
The gas after the adsorption treatment, usually a product gas, is introduced into the seal portion 9 through the pipes 10 and 11 and the nozzle connection portion is sealed with the product gas, so that the gas inlet / outlet terminal, that is, the air from the nozzle connection portion Can be prevented from deteriorating the adsorbent due to contamination of the adsorbent or lowering the purity of the product.

The adsorption tower obtained as described above can be used for various purposes, and the application is not limited. However, the pretreatment for removing water and carbon dioxide in the cryogenic air separation apparatus is not limited. It can be suitably used for separation of air components by an adsorption device or a pressure fluctuation adsorption method. Further, depending on the temperature characteristics of the outer shell constituent material and the operating temperature range of the separation device, the present invention can be applied to a temperature fluctuation adsorption method.

FIG. 5 is a system diagram showing an example of a pressure fluctuation adsorption / separation apparatus using three adsorption towers 1. As described above, the adsorption tower of the present invention can be used in the same manner as a conventional adsorption tower made of a thick metal material. Done at
It is preferable to operate by a vacuum regeneration pressure fluctuation adsorption separation method in which the regeneration is performed under reduced pressure.
It is preferable to carry out at a pressure lower than the atmospheric pressure.

In FIG. 5, reference numeral 21 denotes a blower for introducing a raw material gas (raw air), 22 denotes a vacuum pump for performing vacuum regeneration, and 23 denotes a product gas storage tank. The driving method is a well-known driving method, for example,
Since a method described in 173746 and other appropriate methods can be appropriately selected, detailed description thereof will be omitted.

[0025]

EXAMPLE A flexible cylindrical container made of silicone rubber having a thickness of 2 mm (both ends are semicircular, 8 cm in diameter, 45 cm in length,
In an inner volume of about 2.3 liters), about 1.2 kg of alumina gel was filled in about 5 cm in the lower part, and about 1.2 kg of zeolite A (pellet) was filled in about 40 cm in the upper part. Fig. 5
As shown in (1), pipes and valves were arranged (a flow control valve was installed in place of the blower), and an experiment was performed to generate oxygen from air so that VPSA operation could be performed. The supply of the raw air was controlled by suction by a vacuum pump and adjustment of a flow control valve.

The VPSA operation includes adsorption (50 to 70 seconds),
Each step of equalizing pressure reduction (4-6 seconds), vacuum regeneration (12-18 seconds), purge regeneration (35-45 seconds), equalization pressurization (4-6 seconds), pressurization (46-54 seconds) Was repeated. Various operations were attempted by changing the time of each step within the above range.
The adsorption pressure was adjusted to approximately 0.95 atm. The degree of vacuum during regeneration was approximately 200 mmHg. Approximately 500 to 700 liters of raw material air per hour converted to standard conditions (0 ° C., 1 atm) is converted to oxygen, with a purity of 91 to 93% by volume, converted to standard conditions, approximately 50 to 70 liters per hour (100% concentration converted). Obtained. The oxygen yield is approximately 46
~ 54%.

Although the outer container was made of flexible silicone rubber, the adsorption cylinder did not deform. That is, the shape can be maintained by the frictional force between the adsorbents or between the adsorbent and the silicone rubber wall. In addition, since all the steps are set to the atmospheric pressure or less, the atmospheric pressure acts to maintain the shape of the cylinder.

After performing the VPSA operation for about 2000 hours with the above apparatus, the adsorbent was taken out and the state was examined. As a result, almost no powdering occurred, and there was no practical inconvenience.

[0029]

As described above, according to the present invention,
Since the container containing the adsorbent does not need to be strong enough to withstand external pressure, the container is lighter and production costs are reduced. A portable suction device facilitates movement, and a large suction device simplifies foundation work and reduces costs. The shape of the outer shell of the adsorption tower does not necessarily need to be cylindrical or spherical,
Since it can be formed in a cubic or rectangular parallelepiped shape, there is no useless space such as a cylindrical horizontal or spherical container used in a large-sized suction device in the prior art, and the equipment is compact. In the large-sized adsorption device according to the present invention, the number of adsorbent units may be increased as needed,
There are no restrictions on construction or transportation. The adsorbent unit is
Since it is manufactured in a factory, there is no work to fill the adsorbent at the construction site, so that troubles such as absorbing moisture in the air during the work of filling the adsorbent and reducing the adsorption capacity are eliminated.
Furthermore, since the packing density of the unit of the adsorbent becomes uniform, the deterioration of the separation performance due to the gas drift is small.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of an adsorption tower according to the present invention.

FIG. 2 is a partial sectional view of a main part showing another embodiment of the adsorption tower.

FIG. 3 is a sectional view of a main part showing still another embodiment of the adsorption tower.

FIG. 4 is a system diagram showing an example of using an adsorption tower.

FIG. 5 is a system diagram showing an example of a pressure fluctuation adsorption separation device using the adsorption tower of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Adsorption tower, 2 ... Adsorbent, 3 ... Outer shell, 4, 5 ... Nozzle,
6 sealing material, 7 coating material, 9 seal part

Claims (9)

[Claims] 1. An adsorption tower filled with an adsorbent therein, wherein the outer shell of the adsorption tower is formed of a flexible material. 2. The adsorption tower according to claim 1, wherein the adsorption tower has a structure in which the adsorbent filled in the tower receives an external pressure applied to the outer shell. 3. The adsorption tower according to claim 1, wherein the outer shell is formed by coating an outer surface of an adsorbent formed in a predetermined shape with an airtight treatment material. 4. The adsorption tower according to claim 3, wherein the adsorbent is formed in a tower shape in advance. 5. The adsorption tower according to claim 1, wherein the adsorption tower includes a sealing portion for sealing a connection portion of the gas inlet and outlet with the gas after the adsorption treatment. 6. A pressure fluctuation adsorption separation apparatus comprising the adsorption tower according to claim 1. 7. A gas separation method comprising performing gas separation using the adsorption tower according to claim 1. 8. The gas separation method according to claim 7, wherein the regeneration of the adsorbent in the adsorption tower is performed by a vacuum regeneration method. 9. The gas separation method according to claim 7, wherein when the gas is separated by the pressure fluctuation adsorption separation method, the operation pressure of all the steps is performed at atmospheric pressure or lower.