JPH05317632A - Gas adsorptive separator and method therefor - Google Patents

Abstract

PURPOSE:To provide a device and method for separating mixed gas by adsorption with high purity and high recovery. CONSTITUTION:In a gas adsorptive separator provided with an adsorbent packed tank 1, plural gas dispersion plates 2 arranged in the same direction inside the packed tank 1, a raw gas supply pipe 3 installed outside the packed tank 1, a product gas outflow pipe 4 and a desorbed gas discharge pipe 5, the desorbed gas discharge pipe 5 is arranged substantially in the same direction as the installing one of the gas dispersion plate 2. The operation is done so that the gas flow direction in the adsorption process may intersect perpendicular to that in the desorption one. As a result, the mixed gas uniformly comes into contact with an adsorbent in the adsorption process and the desorption and regeneration are made with extreme smoothness and in a short time at which the flow process of the adsorption and desorption of adsorbed gas is not resisted or disturbed by the dispersion plates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adsorbing and separating a gas and an apparatus therefor.

[0002]

2. Description of the Related Art As a method for separating a mixed gas containing two or more gas components with an adsorbent, there have been conventionally used PSA (Pressure Swing Adsorption), TSA and TSA.
Method (Thermal Swing Adsorption), PTSA method (Pressure
and Thermal Swing Adsorption) are known.
For example, the PSA method is known as a technology for separating a gas by utilizing the adsorption equilibrium or a difference in the adsorption rate between an adsorbent and a specific gas, such as air separation, hydrogen purification, carbon monoxide and carbon dioxide recovery. Is being actively applied to.

Conventionally, in the PSA method, a vertical cylindrical adsorption tower, which is used in various gas separation processes which have already been industrialized, is used. The adsorption tower is shown in FIG.
In the adsorption step, a raw material gas (mixed gas) is fed from the bottom of the tower, a product gas is taken out from the top of the tower, and a desorption gas is discharged from the bottom of the tower during regeneration. Therefore, as the structure of the adsorption tower, the opening (tube) for supplying the source gas and discharging the desorption gas is installed at the bottom of the tower, and the product gas outlet is provided at the top of the tower.
In order to disperse the raw material gas more evenly and to make good contact with the adsorbent, a baffle plate is provided below the inside of the adsorption tower, and the upper part of the plate is adsorbed through the space for dispersing the raw material gas. An agent support plate is installed.

The adsorption device having such a structure has the following problems. (1) At the time of adsorption, since the linear velocity of the gas needs to be above a certain level in order to improve the contact efficiency between the gas and the adsorbent and facilitate the adsorption, the aspect ratio of the adsorption tower is generally 2 to. It was about 5 times, and in particular, for treating a gas having a slow adsorption rate, a longer adsorption tower had to be used.
Therefore, in such an adsorption tower, especially the adsorbent at the upper part of the adsorption tower may not partially function (do not make uniform contact with the raw material gas), and when desorbing the desorbed gas from the bottom of the adsorption tower during desorption. As a result, a pressure difference occurs between the upper part and the lower part of the tower, and desorption becomes more difficult in the upper part of the tower. (2) Since the gas dispersion plate and the adsorption support plate used for the uniform distribution of the supply gas become a resistance during the gas desorption operation during regeneration, it is necessary to desorb the adsorbed gas almost completely. However, a vacuum pump with a large capacity must be used for suction, and the equipment cost and power consumption cost are large, which is not economical. (3) In particular, when processing a raw material gas containing a large amount of gas components adsorbed by the adsorbent, the desorption process requires a long time, which causes an imbalance with the time required for the adsorption process. .. Therefore, the number of adsorption towers must be increased. (4) Due to the gas diffusion, the space provided under the adsorption tower becomes a dead space, and the raw material gas existing there is mixed with the desorption gas during regeneration, which causes the purity of the desorption gas to decrease.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors found that a gas dispersion plate or the like in an adsorption tank is a gas flow during the desorption-regeneration process. It was found that it is preferable that the gas flow direction at the time of adsorption and the gas flow direction at the time of desorption be orthogonal (cross) so as not to cause the resistance of No. 2, and the present invention has been completed.

That is, according to the present invention, an adsorbent filling tank, a plurality of gas dispersion plates arranged in the same direction inside the filling tank, a raw material gas supply pipe installed outside the filling tank, and a product gas outflow pipe. And a desorption gas discharge pipe, wherein the desorption gas discharge pipe is installed in substantially the same direction as the arrangement direction of the gas dispersion plate. Device, adsorbent filling tank, a plurality of gas dispersion plates arranged in the same direction inside the filling tank, raw material gas supply pipe installed outside the filling tank, product gas outflow pipe, and desorption gas discharge In a method for separating a gas by a gas adsorption / separation device including a pipe, the gas separation method is characterized by operating so that the gas flow direction in the adsorption step and the gas flow direction in the desorption step are orthogonal to each other. is there.

The present invention will be described below with reference to the drawings.
FIG. 1 is an external view showing an example of the gas adsorption / separation device of the present invention, and FIG. 2 is a plan sectional view of the device during an adsorption step, and FIG.
Is a side cross-sectional view of the device during a detaching process. In the device of the present invention, a raw material gas supply pipe 3 and a product gas outflow pipe 4 are installed on the left and right of the adsorbent filling tank 1, a desorption gas discharge pipe 5 is installed in the lower portion of the tank, and an adsorbent filling port 6 is installed in the upper portion. .. The exhaust pipe 5 is provided with a suction pump 7 in order to sufficiently desorb the adsorbed gas from the adsorbent in the regeneration process. Inside the adsorbent filling tank 1, as shown in FIGS. 2 and 3, the dispersion surface of the gas dispersion plate 2 is arranged at right angles to the supply pipe 3 and in the same direction as the discharge pipe 5. ing. In the dispersion plate 2, a plurality of, for example, four, are arranged in the same direction so that the raw material gas is well dispersed and almost uniformly contacts the adsorbent. By providing a large number of pores in the dispersion plate 2, the gas reaches the back surface of the dispersion plate and the gas and the adsorbent are uniformly contacted with each other. An adsorbent such as zeolite molecular sieve or carbon molecular sieve is filled in the tank without forming a dead space.

The shape of the adsorbent filling tank 1 is preferably a disc, an ellipse, or a sphere from the viewpoint of adsorption and desorption efficiency.
The gas supply pipe 3 and the outflow pipe 4 are provided on the left and right in the longitudinal direction (horizontal direction) of the disk or elliptical packing tank so that the chances of contact with the adsorbent are increased, and the desorption gas exhaust pipe 5 is installed vertically. It When it is desired to use a vertical cylindrical tank, a desorption gas discharge pipe 5 is installed at the center of the tank, a gas supply pipe 3 is installed at the bottom, and a product gas outflow pipe 4 is installed at the top.

Next, the adsorption separation of the mixed gas by the gas separation device of the present invention will be described. In the mixed gas adsorption step, the raw material gas is introduced from the supply pipe 3 in a direction perpendicular to the dispersion plate 2, and in the direction of the outflow pipe 4 while making sufficient contact with the adsorbent as indicated by the broken line arrow in FIG. And proceed. that time,
Part of the gas component in the raw material gas is adsorbed, and the gas component that is not adsorbed flows out from the outflow pipe 4 and is recovered as a product gas. In the desorption process, the valves 8 and 9 provided in the supply pipe 3 and the outflow pipe 4 are closed, and the desorption gas is discharged from the discharge pipe 5. When the adsorption tank is under pressure, the desorbed gas is discharged by its own pressure, but after the atmospheric pressure is reached, the adsorbed gas is almost completely removed by evacuation by the suction pump 7, for example, a vacuum pump. Can be desorbed from the adsorbent. In the device of the present invention, since the dispersion plate 2 is arranged parallel to the gas flow at the time of desorption, the desorption gas flows as shown by the broken line arrow in FIG. 3, and the dispersion plate becomes a resistance to the gas flow. Never. Therefore, the desorption gas can be discharged very smoothly in a short time. If necessary, in order to carry out desorption more completely, a gas for cedar can be introduced from the upper part of the adsorption tank 1.

Although the adsorption step and the desorption step are repeated by the above-mentioned operation, industrially, the adsorbent-filled tank 1 usually has 2
By adopting a tower type or a multi-column type, the adsorption step and the desorption / regeneration step and the like are sequentially performed in each tank, whereby the gas adsorption separation can be continuously carried out. INDUSTRIAL APPLICABILITY The separation device and method of the present invention can be applied to the separation and purification of PSA method, TSA method, PTSA method and various conventionally known mixed gases. As the target gas, for example, nitrogen, oxygen,
Examples include air, carbon monoxide, reformed gas, and rare gas.

For example, an example of the apparatus of the present invention used for adsorbing and separating a mixed gas containing methane, ethylene, and argon as the main components discharged from an ethylene oxide production plant by the PAS method is as follows. ³ / hr
, The adsorbent filling tank 1 has a diameter of 265 mm and a height of 18
A size of about 0 mm is suitable. A raw material gas supply pipe 3 of 6/4 mmφ and a product gas outflow pipe 4 are provided on the left and right of the filling tank 1 in the lateral direction, and a desorption gas discharge pipe 5 of 10/8 mmφ is provided at the bottom of the filling tank 1. 3 mm as the gas distribution plate 2 arranged in the filling tank 1 in a direction perpendicular to the supply pipe 3 and in the same direction.
Four 80 mm × 120 mm rectangular perforated plates having about 10 φ holes are used.

[0012]

The gas adsorption separation apparatus and method of the present invention are
Since the operation in the desorption process is easy and efficient, it is very effective for treating a raw material gas containing a large amount of easily adsorbed gas components, which has been said to be uneconomical and inappropriate in the conventional PSA method. .. In addition, in the conventional adsorption tower, the regeneration of the gas having a slow adsorption rate could not be efficiently and economically performed, but the apparatus and method of the present invention have good desorption performance, and thus such gas treatment Can also be easily implemented. Further, in the large-scale PSA method, the process according to the present invention can be put to practical use even for a process in which the capacity of the vacuum pump used for sucking the adsorbed gas is a bottleneck.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a gas adsorption separation device of the present invention.

FIG. 2 is a conceptual diagram showing a plane cross section of FIG.

FIG. 3 is a conceptual diagram showing a side cross-section of FIG.

FIG. 4 is a conceptual diagram showing a conventional typical gas separation / adsorption tower.

[Explanation of symbols]

 1 Adsorbent filling tank 2 Gas dispersion plate 3 Raw material gas supply pipe 4 Product gas outflow pipe 5 Desorption gas discharge pipe 6 Adsorbent filling port 7 Suction pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Saito 17-1 Towada, Kamisu-machi, Kashima-gun, Ibaraki Prefecture -1 Mitsubishi Petrochemical Engineering Co., Ltd. Kashima Branch Office

Claims (3)

[Claims] 1. An adsorbent filling tank, a plurality of gas dispersion plates arranged in the same direction inside the filling tank, a raw material gas supply pipe, a product gas outflow pipe, and a desorption gas installed outside the filling tank. A gas adsorption / separation device comprising an exhaust pipe, wherein the desorption gas exhaust pipe is installed in substantially the same direction as the arrangement direction of the gas dispersion plate. 2. The apparatus according to claim 1, wherein the shape of the adsorbent filling tank is disk-like, elliptical or spherical. 3. An adsorbent filling tank, a plurality of gas dispersion plates arranged in the same direction inside the filling tank, a raw material gas supply pipe installed outside the filling tank, a product gas outflow pipe, and a desorption gas. In a method for separating a gas by a gas adsorption / separation device including an exhaust pipe, the gas separation is characterized in that the gas flow direction in the adsorption step and the gas flow direction in the desorption step are operated so as to be orthogonal to each other. Method.