JPH0663306A - Gas-liquid contact device - Google Patents

Abstract

PURPOSE:To provide a gas-liquid contact device where the pressure loss of perforated plates assembled in a fractionator is decreased and the operating range of the fractionator is made wide. CONSTITUTION:The region of small holes 8 opened obliqutely in the radius direction of a perforated plate 5 is provided. Consequently since by the action of the region of small holes opened obliqutely in an inside direction, the liquid in the outer peripheral part flows in the inside direction, the thickness of the liquid on the perforated plate is made uniform to obtain a gas-liquid contact device having small pressure loss and a wide operating range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid contactor suitable for an air separator for liquefying air and separating nitrogen, oxygen and argon from the air by a rectification operation.

[0002]

2. Description of the Related Art Conventional techniques of gas-liquid contactors include, for example, Japanese Patent Application Laid-Open No. 56-33005, Japanese Patent Publication No. 42-4568, "Shelf for contacting liquid and vapor". is there. Since the liquid flowing on the perforated plate while making contact with the gas is a free flow due to gravity, the liquid height on the perforated plate has a distribution depending on the position of the perforated plate. In these inventions, in order to make this distribution constant, the perforated plate is inclined according to the difference in liquid height and attached to the rectification column to keep the liquid height distribution almost constant and to achieve good gas-liquid contact. This is performed, or a part of the upstream side of the perforated plate is tilted so that steam is blown out to the downstream side of the perforated plate to perform gas-liquid contact.

[0003]

In the air separation device, since the pressure loss of the perforated plate which is installed in the rectification column in several tens of stages directly affects the power consumption of the air compressor, the discharge pressure of the air compressor is reduced. It is no exaggeration to say that represents the performance of the air separation device. Therefore, it is necessary to optimize the gas-liquid flow on the perforated plate in order to fully exhibit the capability of the rectification column having the perforated plate. In a so-called swirl flow type gas-liquid contactor in which a gas-liquid contactor is supported by an outer cylinder and an inner cylinder, and a liquid flows along a circumferential direction on a perforated plate, a liquid film is radially generated by a centrifugal force of the liquid. Causes a difference in thickness. This difference in liquid film hinders the uniform flow of liquid, resulting in pressure loss or
The stagnation of the liquid and the weeping due to the difference in the thickness of the liquid film adversely affect the rectification efficiency. Since the pressure loss of the rectification column greatly affects the power consumption of the air compressor and the like, it is desirable to minimize the pressure loss. The small holes of the perforated plate are opened by punching or the like. The pressure loss at this time is estimated by the sum of the dry pressure loss, the pressure loss due to the thickness of the liquid film, and the pressure loss due to the surface tension, as described in "Distillation Engineering Handbook" and the like. In order to reduce each pressure loss, there are a method of increasing the hole diameter of the small holes of the porous plate, a method of inclining the porous plate to reduce the thickness of the liquid film, and the like.

However, since a perforated plate used in an air separation device or the like is required to have a high rectification efficiency, increasing the pore size causes weeping or partial foaming of gas-liquid to lower the rectification efficiency. In addition, if the perforated plate is tilted and incorporated in the rectification column, its structure is difficult and there is a risk that the cost of the device will increase. Therefore, reducing the pressure loss,
In order to provide a higher rectification efficiency, it is essential to make the liquid on the perforated plate flow uniformly and without stagnation so that the gas-liquid flow is optimized.

An object of the present invention is to provide a gas-liquid contactor which maintains good gas-liquid contact on a perforated plate, has a small pressure loss, is less likely to cause weeping, and has a wide operating range of the rectification column. And

[0006]

In order to achieve the above object by a gas-liquid contact device of a swirling flow type, a porous film having a uniform thickness of a liquid film on a perforated plate, a small pressure loss, and a weaping resistant This is accomplished by providing a plate.
That is, a perforated plate having small holes opened by means such as punching is formed by combining a small hole opened in the vertical direction and a small hole opened inclined inward, and The structure is such that the area of the opened small holes is installed in the radial direction, or the structure is formed by the small holes opened by inclining the perforated plate.

[0007]

Operation: The liquid flowing into the perforated plate flows into the perforated plate from the overflow pipe of the upper perforated plate and swirls along the circumference of the perforated plate by the natural flow due to gravity, and overflows. It flows from the tube to the lower perforated plate. Gas-liquid contact is carried out with gas and liquid on the perforated plate. Since the flow of liquid on the perforated plate is a free flow due to gravity, when gas and liquid come into contact with the rising gas from below, the upward flow of this rising gas acts as a screen against the liquid flow, and the liquid becomes smooth. It becomes an obstacle for flowing the perforated plate. In other words, the liquid may not be able to flow smoothly through the perforated plate due to the obstacle of the gas rising in the small holes of the perforated plate.

On the other hand, since the liquid on the perforated plate flows while swirling on the perforated plate, a centrifugal force is generated in the liquid. Therefore, the thickness of the liquid film is large in the outer peripheral direction of the perforated plate, and is small on the contrary on the inner side, which causes a difference in the thickness of the liquid film on the perforated plate. In the present invention, the small holes of the perforated plate are opened along the flow direction of the liquid, and the region having the small holes substantially in the shape of the oblique holes transfers the kinetic energy of the gas rising in the perforated plate to the promotion of the liquid flow. Has an effective effect on force. In the present invention, since the region having the small holes in the shape of the oblique holes is installed in the radius and the circumferential direction of the perforated plate, the kinetic energy of gas is increased by the small holes in the shape of the oblique holes. Effectively acts on the force for the liquid above to flow smoothly, and retains more liquid than necessary,
Alternatively, the difference in the thickness of the liquid film on the perforated plate due to the centrifugal force can be prevented, and the liquid on the perforated plate can be made to flow uniformly. In other words, the small holes in the shape of oblique holes have the effect of making the kinetic energy of the rising gas a smooth flow of the liquid and making the difference in the thickness of the liquid film on the perforated plate due to centrifugal force more uniform. And the gas-liquid contact can be performed. Also,
The weeping in which the liquid descending from the perforated plate falls directly from the small holes of the perforated plate onto the lower perforated plate without passing through the overflow pipe,
It adversely affects the rectification efficiency. The presence or absence of weeping is determined by the shape of the small holes and the thickness of the liquid film on the perforated plate. According to the present invention, since the liquid film thickness can be made uniform, it also has the effect that weeping is less likely to occur and a wide operating range can be secured.

[0009]

1 and 2 show a gas-liquid contactor according to a first embodiment of a rectification column incorporating the gas-liquid contactor of the present invention. A gas-liquid contactor incorporating the perforated plate according to the present invention,
The liquid is a swirling flow method in which a liquid flows along a circumferential direction on a perforated plate, and the illustrated embodiment is a gas-liquid contactor having a structure having small holes that are inclined and opened in one region in the radial direction. Figure 1
In the above, the gas-liquid contactor 1 is incorporated in the rectification column 2 in several tens of stages. The rectification column 2 is composed of an outer cylinder 3, an inner cylinder 4 called a mandrel, and a gas-liquid contactor 1. The gas-liquid contacting device 1 is composed of a perforated plate 5 having a large number of small holes, a liquid receiving box 6 for allowing a liquid from above to flow into the perforated plate 5, and an overflow pipe 7 for flowing out the liquid downward. Has been done. The liquid flowing out from the liquid receiving box 6 flows into the perforated plate 5, flows while swirling along the outer cylinder 3 and the outer cylinder 4 as shown by the arrows, and flows into the overflow pipe 7. On the other hand, the gas from below rises from the small holes 8 and 9 of the perforated plate 5 and comes into contact with the liquid on the perforated plate 5 for mass transfer (rectification). In the conventional gas-liquid contact device, the liquid on the perforated plate flows along the circumference, so that the centrifugal force of the liquid causes the thickness of the liquid film to be large outside the circumference and conversely small inside. There is a difference in the thickness of the liquid film above. In the present invention, the perforated plate 5 is constituted by a region I having a small hole 9 opened vertically and a region II having a small hole 8 opened inwardly at least a certain region in the radial direction. The inclination direction is formed along the inner side of the liquid flow direction, and is specifically opened at least inward of the tangential direction.

In FIG. 2, the gas-liquid contactor 1 is composed of a region I having a small hole 9 opened perpendicularly to the perforated plate 5 and a region II having a small hole 8 opened obliquely, region
The small hole 8 of II is opened toward the inside of the gas-liquid contact device 1.

Since the present invention is configured as described above, the liquid on the outer peripheral portion of the gas-liquid contactor 1 is caused by the energy of the gas rising along the small hole 8 that is inclined and opened.
A force that flows in the opening direction of the small holes 8 is applied. Therefore, in FIG. 1, the liquid that has flowed into the perforated plate 5 from the liquid receiving box 6 is a flow of the liquids 11 and 12 on the perforated plate 5 in which the flow direction is slightly inward. Therefore, the liquid film thickness on the outer peripheral portion of the gas-liquid contact device 1 due to the centrifugal force is relaxed, and the difference in the liquid film thickness on the porous plate 5 can be reduced. In addition, since the liquid in the outer peripheral portion can be made to flow smoothly, stagnation of the liquid can be eliminated. Therefore, it is possible to provide a gas-liquid contactor having a small pressure loss, high efficiency, and a wide operating range.

FIG. 3 shows a perspective view of the small holes of the perforated plate. This drawing specifically explains the flow of the liquid gas. In the region I, the small holes are opened vertically, and in the region II, the small holes are inclined and opened inward. Therefore, the gas 13 (broken line) from below in the region II rises along the opening direction, so that the liquid 11 (solid line) flowing in the vicinity flows inward. In this way, the liquid in the region II where the thickness of the liquid film due to the centrifugal force is large is flowed inward, and a uniform liquid film thickness can be obtained.

FIG. 4 shows a second embodiment of the present invention. The gas-liquid contactor in the first embodiment is a perforated plate that is composed of a small hole that is vertically opened and a small hole that is inclined and opened. The perforated plate 21 is composed of the small holes 20. The opening direction of the small holes 20 that are opened at an angle is from the upstream side to the downstream direction of the liquid flow on the perforated plate 21 toward the inner side, and preferably the small holes 20.
The opening is inward from the tangential direction at the radius of. The gas 22 from below rises along the small holes 20, and the flow of this gas 22 allows the liquid on the porous plate 21 to smoothly flow. Therefore, in this embodiment, the liquid on the perforated plate can be made to flow more uniformly, and as a result, there is an effect of obtaining a more uniform liquid film thickness on the perforated plate.

The inclination of the small holes opened at an angle (the angle from the vertical direction to the horizontal direction of the perforated plate), the size of the small holes, the opening ratio of the perforated plate, etc. are important factors for the flow of the liquid. Therefore, in the above first or second embodiment, it is possible to combine these factors to form a perforated plate. In this case, the inclination, the size of the small hole, and the opening ratio are
Preferably, the structure is such that the outer peripheral portion is larger and the inner peripheral portion is gradually or gradually smaller. By doing so, the liquid on the porous plate can be made to flow more uniformly.

FIG. 5 shows the third to fifth embodiments of the present invention, in which a porous plate constituting a gas-liquid contactor is radially divided into several segments, and these segments are combined to form a gas-liquid contactor. To do. In the third embodiment,
The perforated plate 30 of one segment is provided with the perforated plates of the above-mentioned regions I and II, and several segments are combined into one perforated plate to form a gas-liquid contactor. In the fourth embodiment, the perforated plate 31 of one segment is manufactured by dividing the above region I and region II into 32 and 33, respectively, and assembled as one segment. Further, in the fifth embodiment, the perforated plate 34 of one segment is divided into the perforated plates having different specifications (for example, the above-mentioned inclination, the size of the small holes, and the opening ratio, for example, the inclination) and manufactured. However, it is assembled as one segment. According to these embodiments, the effect that the perforated plate can be manufactured more easily is obtained.

Further, it is also possible to construct a gas-liquid contactor by combining at least two kinds of perforated plates of segments having different inclinations, small hole sizes and opening ratios in the circumferential direction. That is, by configuring such a perforated plate by combining from the liquid inlet part on the perforated plate to the liquid outlet part,
The effect of smoothing the flow of the liquid on the perforated plate is obtained.

[0017]

According to the present invention, a gas-liquid contactor of the swirl flow type is opened with a perforated plate having small holes opened vertically and inclined along the flow direction of the liquid on the perforated plate. It is possible to make the thickness of the liquid film on the perforated plate uniform by using a perforated plate with small holes or a perforated plate with only small holes that are inclined and opened. The stagnation of the flow can also be reduced, thereby providing a gas-liquid contactor with a small pressure loss, good gas-liquid contact, and a wide operating range.

[Brief description of drawings]

FIG. 1 shows a plan view of a gas-liquid contact device according to a first embodiment of the present invention.

FIG. 2 shows a cross-sectional view of a gas-liquid contact device according to the first embodiment of the present invention.

FIG. 3 shows a perspective view of a perforated plate of the present invention.

FIG. 4 shows a sectional view of a gas-liquid contactor according to a second embodiment of the present invention.

FIG. 5 shows a plan view of a gas-liquid contact device according to third to fifth embodiments of the present invention.

[Explanation of symbols]

1 ... Gas-liquid contactor, 2 ... Fractionation tower, 5 ... Perforated plate, 8, 9 ...
Small holes, 11, 12 ... Liquid, 13 ... Gas.

Claims (7)

[Claims] 1. A gas-liquid contactor having a perforated plate having a large number of small holes and an overflow pipe, in which a liquid is lowered from above and a gas is raised from below so that the liquid and the gas contact each other on the gas-liquid contactor. In the gas-liquid contactor in which the liquid is made to flow along the circumferential direction on the perforated plate by contacting the rectifying operation with the porous liquid, the gas-liquid contactor has a pore having small holes opened in the vertical direction. 1. A gas-liquid contactor comprising a plate and a perforated plate having small holes that are inclined in at least one region in the radial direction. 2. The gas-liquid contactor according to claim 1, wherein the perforated plate is composed of small holes that are inclined and opened. 3. The gas-liquid contact device according to claim 1, wherein the small hole that is inclined and opened has an opening direction that is at least inside a tangential direction at its radius. 4. The gas-liquid contact device according to claim 1, wherein the perforated plate having the small holes opened is radially divided into several segments, and the segments are combined to form a gas-liquid contact device. Contact device. 5. A gas-liquid contactor comprising a perforated plate having small holes opened in the vertical direction and a perforated plate having small holes inclined and opened separately and combined to form one segment. The gas-liquid contact device according to claim 4, wherein 6. Perforated plates having different inclinations, small pore sizes, and different opening ratios are separately formed, and at least two perforated plates are provided in the radial direction.
The gas-liquid contact device according to claim 4, wherein one or more kinds of segments are combined to form a gas-liquid contact device. 7. A perforated plate having different inclinations, small hole sizes, and opening ratios is made into one segment, and at least two kinds of the perforated plates in the circumferential direction are combined to form a gas-liquid contactor. The gas-liquid contact device according to claim 6, which is configured.