JPH07178308A - Gas separating and recovering device - Google Patents

Abstract

PURPOSE:To provide a gas separating and recovering device capable separating a high-purity gas with high efficiency. CONSTITUTION:Multiple-cylinder adsorption towers A and B packed with an adsorbent to selectively adsorb a specified component gas are provided, and the volume of a dead space 1 is decreased by reducing the diameters of the upper and lower gas inlet and outlet. Consequently, the space to be purged with the product gas is decreased. The cylinders of the adsorption towers A and B are arranged alternately an placed in the same water vessel, and the towers A, B are in conductive relation through water. As a result, the unwanted temp. change in the towers A and B due to the heat produced by the adsorbent in adsorption and the heat adsorbed by the adsorbent in desorption is suppressed. A high-purity gas is efficiently recovered in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an adsorbent which selectively adsorbs a specific component gas, and a gas by a pressure swing cycle method in which a mixed gas is separated by applying a pressure change to cause adsorption and desorption. The present invention relates to a separation / collection device.

[0002]

2. Description of the Related Art This gas separation / recovery device is used to recover a target gas from a raw material gas, and uses a characteristic of an adsorbent that adsorbs the gas in proportion to the pressure. Adsorption (hereinafter abbreviated as PSA) type gas separation and recovery system. FIG. 8 shows a model of a conventional example of a PSA gas separation and recovery apparatus for recovering CO ₂ gas from combustion exhaust gas. In FIG. 8, the raw material gas, that is, the combustion exhaust gas is collected in the inlet gas holder 5 and sent to the adsorption tower A by the blower 6. The adsorbent 2 in the adsorption tower A intensively adsorbs CO ₂ gas under high pressure, and most of the gas other than CO ₂ gas is discharged without being adsorbed.

Next, since the gas remaining in the upper and lower dead spaces 1 in the adsorption tower A contains a large amount of raw material gas of low CO ₂ purity, the product gas is returned from the outlet gas holder 3 through the pipe 7, Is sent to the adsorption tower A,
The gas of low CO ₂ purity remaining in the adsorption tower A is discharged, and C
Substitute with O ₂ having high purity. Then, the valve on the inlet side of the raw material gas at the top of the tower is closed, the CO ₂ gas in the adsorption tower A is sucked by the vacuum pump 4, the CO ₂ is desorbed from the adsorbent 2 and sent to the outlet gas holder 3. By performing this operation alternately in the adsorption towers A and B as shown in FIG.
It makes it possible to recover O ₂ .

[0004]

In the cylindrical vertical adsorption tower such as the conventional apparatus described above, since the dead space 1 has a large volume, the adsorption tower is used to replace the gas in the dead space 1 from the outlet gas holder 3. It is difficult to control the product gas supply rate that leads to That is, if the product gas supply amount is too large, the gas having a high product gas concentration is discharged as it is, and the gas recovery rate is reduced. Further, if the product gas supply amount is too small, the raw material gas still remains in the adsorption tower, which lowers the purity of the product gas. Therefore, it is desirable to reduce the volume of the dead space 1 in order to reduce the adjustment range of the supply amount and reduce the waste of product gas.

Further, in the conventional adsorption tower, the adsorbent is adversely affected by the heat generated by the heat of adsorption during adsorption and the heat absorbed by the heat of desorption during desorption. That is, a lower temperature in the adsorption step and a higher temperature in the desorption step are preferable conditions for the reaction of the adsorbent, whereas in the conventional adsorption tower, the temperature is higher during adsorption and lower during desorption. It is preferable to reduce such temperature changes in the adsorption tower.

Therefore, the present invention solves these problems found in the conventional gas separation and recovery apparatus using the pressure swing method, reduces the dead space of the adsorption tower, and improves the separation gas recovery rate. An object is to provide a gas separation and recovery device. Furthermore, the present invention aims to provide a gas separation / recovery device having a high gas separation / recovery efficiency, which is not preferable for the adsorption and desorption actions in the adsorption tower, prevents the temperature change of the adsorption tower due to heat generation and heat absorption, and improves the performance of the adsorbent. I am trying. Another object of the present invention is to provide a gas separation / recovery device that can be easily applied to a conventional device.

[0007]

According to the present invention, a mixed gas of an adsorbent gas and a hardly adsorbed gas is used by using a plurality of adsorption towers filled with an adsorbent which selectively adsorbs a specific component gas. In order to solve the problem of reducing the dead space in the adsorption tower of the gas separation and recovery apparatus for separating the adsorbent gas and the hardly adsorbed gas by using the pressure swing method, each adsorption tower is provided with a plurality of adsorption towers. To form a multi-cylinder type adsorption tower.

The case where the adsorbent contained in one cylindrical vertical adsorption tower is divided into, for example, four elongated adsorption towers to form a four-column type adsorption tower (the same amount of adsorbent) will be described.
If the size of the cylindrical vertical adsorption tower is 2 m in diameter and 5 m in height, the adsorption tower size when it is a 4-cylinder type is 1 in diameter.
It can be divided into m and height of 5 m. In this case comparing the dead space to become 33.5M ³ in the conventional cylindrical fresh type, it will decrease 16.75 m ^3, and the 50% in 4 cylinder type.

Therefore, if the cylindrical vertical adsorption tower is divided into four cylinders, the adjustment range of the product gas returned from the outlet gas holder can be reduced by 50%. As a result, the product gas, such as CO ₂ gas, released as exhaust gas can be significantly reduced, and the recovery rate indicated by the amount of CO ₂ contained in the product gas relative to the amount of CO ₂ contained in the raw material gas can be improved. it can. As described above, according to the present invention, the dead space can be reduced without deteriorating the dispersibility of the gas in the adsorbent.

Next, in another apparatus according to the present invention, in order to solve the problem of eliminating the adverse effect on the adsorption tower due to the adsorption heat and the desorption heat, the two multi-column adsorption towers are mutually transmitted. Adopt a configuration that is arranged in a thermal relationship. In order to arrange the two multi-column type adsorption towers in a heat transfer relationship, for example, the adsorption towers are placed in a water tank so that water or the like having a higher thermal conductivity than the atmosphere is used as a heat conduction medium. Put in.

By thus providing the two multi-cylinder adsorption towers arranged in a heat transfer relationship in different steps of adsorption and desorption from each other, a process between the multi-cylinder adsorption towers having a large heat transfer area is performed. It is possible to capture the difference in the timing of heat generation and heat absorption due to the deviation of heat transfer, facilitate the transfer of heat between the two adsorption towers, and recover more separated gas.

Further, since the heat capacity becomes considerably large when the structure is put in the water tank, the heat fluctuation in each adsorption tower becomes small and the adsorption performance is improved. As described above, according to the gas separation and recovery apparatus of the present invention, it is possible to transfer heat between the multi-cylinder type adsorption tower and the adsorption tower, thereby improving the adsorption performance without adding a new auxiliary device.

Still another apparatus according to the present invention adopts a structure in which the adsorbent-unfilled portion in the adsorption tower has a small diameter in order to solve the problem of reducing the dead space in the adsorption tower. In this way, the dead space can be reduced by reducing the diameter of only the adsorbent-unfilled portion of the adsorption tower, for example, the inlet / outlet portions of the upper and lower ends of the adsorption tower. As a specific configuration thereof, for example, a shape in which two cones are combined can be considered in consideration of gas dispersibility, and thereby a sufficient effect is exhibited.

By reducing the dead space in the adsorption tower in this way, it is possible to reduce the supply adjustment range of the product gas supplied from the outlet gas holder, thereby significantly reducing the product gas emitted as exhaust gas. It is possible to improve the recovery rate indicated by the amount of the recovery target gas contained in the product gas with respect to the amount of the product gas contained in the raw material gas.

Further, according to the present invention, there is provided a device capable of separating a highly purified gas with high efficiency by using a gas separation / collection device in which the above-mentioned constitutions of the respective inventions are combined.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gas separation / recovery apparatus according to the present invention will be specifically described below based on the illustrated embodiments. In each of the following embodiments, the same parts as those of the conventional device shown in FIG. 8 are designated by the same reference numerals for simplification of description.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It will be described based on. In the apparatus according to this embodiment, the adsorbent, which has conventionally been packed in one adsorption tower, is divided into four, and each is packed in four elongated adsorption towers, which are connected in parallel to the gas flow path to form a four-tube type. Adsorption and desorption are performed in a cylinder simultaneously and in parallel. As described above, the multi-column type adsorption towers A and B
By doing so, the dead space is physically reduced. Thereby, the recovery rate of the separated gas by this device can be improved.

(Second Embodiment) An apparatus according to a second embodiment of the present invention is shown in FIGS. In the second embodiment, the four-column type adsorption towers A and B according to the first embodiment of FIG. 1 are placed in the same water tank 8 filled with water. Adsorption tower A,
As shown in FIG. 3, the adsorption towers of each of the four cylinders constituting B are arranged in a mutually interlocking manner. With this configuration, the two adsorption towers A and B in the adsorption step and the desorption step are brought into a heat transfer relationship by using the water in the water tank 8 as a medium, and the heat generated by the adsorption and the heat absorbed by the desorption are offset each other. It is designed to prevent harmful temperature changes in the adsorption tower.
Further, the heat capacity of each of the adsorption towers A and B is made large by the water in the water tank 8, the heat fluctuation is suppressed, the adsorption and desorption performance is improved, and the same amount of the adsorbent is larger than that of the conventional one. The separated gas can be adsorbed.

(Third Embodiment) An apparatus according to a third embodiment of the present invention will be described with reference to FIG. The conventional adsorption tower was a cylindrical body having a constant diameter, but in the apparatus according to this embodiment, the upper and lower end portions of the adsorption tower, that is, the portion that is not filled with the adsorbent that hits the inlet / outlet portion of the gas has a small diameter. Is. With such a configuration, the dead space in the adsorption towers A and B not filled with the adsorbent 2 is reduced,
The recovery rate of the separated gas is improved.

(Fourth Embodiment) An apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. Also in the apparatus according to this embodiment, the diameter of the adsorbent-unfilled portion in the adsorption towers A and B is made smaller and the dead space 1 is made smaller. In this embodiment, the dead space 1 at the upper and lower ends of the adsorption towers A and B is reduced by transforming the cone into a combination of two cones so that the diameter is gradually reduced toward the inlet and outlet. , The recovery rate is improved.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
Explained by. This embodiment is a combination of the second embodiment shown in FIGS. 2 and 3 and the configuration of the third embodiment shown in FIG. That is, each of the adsorption towers A and B is of a four-cylinder type, and the diameters of the gas inlet / outlet portions above and below each adsorption tower are reduced to reduce the dead space 1 not filled with the adsorbent 2 in each adsorption tower. I am trying. Further, the adsorption towers A and B are placed in a water tank 8 filled with water. The four adsorption towers constituting each of the adsorption towers A and B are arranged intricately with each other, as in the case shown in FIG.

With this configuration, the two adsorption towers A and B in the adsorption step and the desorption step are brought into a heat transfer relationship with the water in the water tank 8 as a medium to prevent temperature changes harmful to the respective steps. It has become. In addition, each adsorption tower A, B
Since the heat capacity of the water in the water tank 8 becomes large and the heat fluctuation is suppressed, the adsorption and desorption performance is improved, and the same amount of adsorbent can adsorb a larger amount of separation gas than the conventional one. As described above, according to the apparatus of this embodiment, the separated gas can be efficiently collected with high purity.

The present invention has been specifically described above based on the illustrated embodiments, but the present invention is not limited to these embodiments, and the shape and structure thereof are within the scope of the present invention shown in the claims. It goes without saying that various changes may be added to the. For example, in the above-mentioned embodiment, the multi-cylinder type adsorption tower is exemplified by the four-cylinder type, but it is not limited to this.

[0024]

As described above in detail, according to the present invention, a high-purity separation gas can be obtained by changing only the adsorption tower to a multi-cylinder type or a different diameter without changing other auxiliary equipment. It is possible to provide a gas separation / recovery device capable of highly efficient recovery. Further, according to the present invention, in addition to a multi-column type adsorption tower,
Provided is an apparatus capable of collecting separated gas more than ever before by simply adding a water tank to the apparatus.

[Brief description of drawings]

FIG. 1 is an equipment layout diagram showing the configuration of a gas separation and recovery apparatus according to a first embodiment of the present invention.

FIG. 2 is a device layout diagram in the second embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a device layout diagram in the third embodiment of the present invention.

FIG. 5 is a device layout diagram in the fourth embodiment of the present invention.

FIG. 6 is a device layout diagram in the fifth embodiment of the present invention.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is an equipment layout diagram showing the configuration of a conventional gas separation and recovery apparatus.

FIG. 9 is an explanatory diagram showing the operation of the PSA gas separation and recovery apparatus.

[Explanation of symbols]

 1 Dead Space 2 Adsorbent 3 Outlet Gas Holder 4 Vacuum Pump 5 Inlet Gas Holder 6 Blower 7 Product Gas Pipeline 8 Water Tank

Claims (4)

[Claims] 1. A mixed gas of an adsorbent gas and a hardly adsorbent gas is adsorbed by using a pressure swing method using a plurality of adsorption towers filled with an adsorbent that selectively adsorbs a specific component gas. In a gas separation and recovery apparatus for separating a reactive gas and a hardly-adsorptive gas, each of the adsorption towers is a multi-cylinder type adsorption tower constituted by connecting a plurality of adsorption towers in parallel to each other. apparatus. 2. The gas separation / recovery device according to claim 1, wherein the two multi-column adsorption towers are arranged in a heat transfer relationship. 3. A mixed gas of an adsorbent gas and a hardly adsorbent gas is adsorbed by using a pressure swing method using a plurality of adsorption towers filled with an adsorbent that selectively adsorbs a specific component gas. A gas separation / recovery device for separating a reactive gas and a hardly-adsorptive gas, wherein the adsorbent-unfilled portion in the adsorption tower has a small diameter. 4. The gas separation / recovery device according to claim 2, wherein the non-adsorbent-filled portion of the multi-column type adsorption tower has a small diameter.