JP2014188508A - Gas separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently separating a target gas composition contained in a mixed gas.SOLUTION: A method for separating a target gas composition from a mixed gas by gas pressure swing adsorption comprises: an adsorption process for bringing a mixed gas into contact with adsorbent layers and adsorbing a target gas composition by the adsorption layers in an adsorption tower 1 having the absorbent layers for adsorbing the target gas composition; and a desorption process for desorbing a desorption gas comprising the target gas composition adsorbed by the adsorbent layer. The adsorption tower 1 has plural adjacent gas separation chambers 14a to 14d, the adjacent gas separation chambers have airtightness and are partitioned by a partition member 12 for conduction of heat between the adjacent gas separation chambers, and further, the tower has the adsorbent layers on both sides of the partition member 12. The adsorption process is carried out in one of the adjacent two gas separation chambers in the adsorption tower 1, the desorption process is simultaneously carried out in the other gas separation chamber, and said adsorption process and desorption process are alternately repeated.

Description

  The present invention relates to a method capable of efficiently separating a gas component to be used (hereinafter referred to as “target gas component”) contained in a mixed gas.

  When a target gas component is separated from a mixed gas having a plurality of gas components, the mixed gas is filled with an adsorbent (often in the form of a sphere of several mmφ or a pellet of several mmφ × several mm length) ( Hereinafter, an operation of circulating the gas to an “adsorption tower” is performed. At that time, for example, when the mixed gas is composed of two components, component A and component B, and the target gas component is A, the gas component A is adsorbed on the adsorbent, and the gas component B that is not the target gas component is used as the adsorbent. In some cases, the gas component is adsorbed by the adsorbent (hereinafter referred to as “adsorbed gas component”).

  In either case, if the mixed gas continues to flow through the adsorption tower, the adsorbent is saturated with the adsorbed gas component and loses the separation ability. Therefore, temporarily stop the flow of the mixed gas and replace the adsorbent with a new one, or desorb the adsorbed gas component from the adsorbent by some method to restore the adsorption capacity of the adsorbent (also called “regeneration”). Operation is required.

  Here, when the adsorbed gas component is a gas component B that is not a utilization target and the amount of the component B contained in the mixed gas is relatively small (ppm order) as compared with the gas component A that is the utilization target. Since the amount adsorbed on the adsorbent is small, it is possible to use the adsorbent over a long period of, for example, one year or longer. Such a case can be dealt with by replacing the adsorbent.

  On the other hand, when both the gas components A and B have a concentration of several volume% to several tens volume%, the amount of the gas component adsorbed on the adsorbent is both large. It is necessary to frequently change the adsorbent, and the cost of the adsorbent increases. Therefore, a regeneration operation different from the replacement of the adsorbent is required.

  Therefore, when the target gas component is separated from the mixed gas, an operation for adsorbing the adsorbed gas component on the adsorbent (hereinafter referred to as “adsorption step”), the adsorbed gas component is desorbed from the adsorbent, and the adsorbent is removed. The operation of regenerating (hereinafter referred to as “desorption process”) is repeated. As a method for separating the target gas component from the mixed gas in this manner, a temperature swing adsorption method (TSA method) that is performed by changing the temperature of the adsorbent, a pressure swing adsorption method that is performed by changing the pressure of the gas (Pressure Swing Adsorption Method, PSA method), PTSA method (Pressure-Temperature Swing Adsorption Method, PTSA method) for changing both pressure and temperature, and VPSA method (Vacuum Pressure Swing Adsorption Method, VPSA method) for reducing pressure during desorption.

  Among these methods, the TSA method requires time to heat and remove the adsorbent, and therefore tends to be limited to applications that operate for a relatively long time, such as dehumidification and removal of trace components such as volatile organic compounds. is there. On the other hand, in the separation of multi-component gas (also referred to as “bulk separation”) in which the concentration of each component contained in the mixed gas to be processed is on the order of several volume% to several tens volume%, an adsorption step It is the mainstream to use the PSA method and the VPSA method, which can avoid the relative increase in the amount of adsorbent used by switching the desorption process in a short time.

  By the way, in order to use less adsorbent efficiently, it is desirable to adsorb more adsorbed gas components to the adsorbent in the adsorption process, and conversely, more adsorbed gas in the desorption process. It is desirable to desorb the components from the adsorbent. FIG. 1 is a diagram showing the relationship between the pressure of a mixed gas and the amount of adsorption of an adsorbed gas component adsorbed on an adsorbent in the PSA method. As shown in FIG. 1 (a), the adsorption amount of the adsorbed gas component to the adsorbent tends to increase as the pressure of the mixed gas introduced into the adsorption tower increases, and the adsorption amount depends on the temperature. The amount of adsorption tends to decrease as the temperature of the agent increases.

For example, when the temperature of the adsorbent is T ₂ in both the adsorption step and the desorption step, as shown in FIG. 1B, the amount Q of the adsorbed gas component separated from the mixed gas by the adsorption step and the desorption step is , based on the relationship between the pressure and suction amount of the mixed gas with respect to the temperature T _2, it is determined by the difference between the pressure P _D of the mixed gas at a pressure P _a and the desorption step of the gas mixture in the adsorption step.

However, in the actual gas separation process, when the adsorbed gas component is adsorbed on the adsorbent in the adsorption process, the adsorption energy (hereinafter referred to as “adsorption heat”) is released, so that the temperature of the adsorbent is reduced. elevated (e.g. from T ₂ to T _3), as shown in FIG. 1 (c), it acts in a direction in which the adsorption amount decreases the adsorbed gas component to the adsorbent.

On the other hand, when the adsorbed gas component is desorbed from the adsorbent in the desorption step, the temperature of the adsorbent decreases (for example, from T ₂ to T ₁ ) to absorb the heat of adsorption, as shown in FIG. As described above, the adsorption amount of the adsorbed gas component from the adsorbent increases, and the desorption amount decreases. As a result, in the actual gas separation treatment, the amount Q of the adsorbed gas component that can be separated by adsorbing and desorbing to the adsorbent is the same as the adsorbent temperature shown in FIG. There is a problem of relatively less than the case. Furthermore, a decrease in temperature of the adsorbent in the desorption process slows the desorption speed of the adsorbed gas component, which increases the time required for the desorption process and increases the time required for the entire process. .

  Under such a background, Patent Document 1 discloses that a large number of adsorption towers are placed in the same water tank and are in a heat transfer relationship with each other, and heat generated in the adsorption process is transferred to the adsorption tower in the desorption process. It describes a technique for reducing temperature changes in the adsorption process and the desorption process by heating.

JP 7-178308 A

  However, in the technique described in Patent Document 1, since heat generated in the adsorption process is transmitted to the adsorbent of the adsorption tower in the desorption process via a structure such as an adsorption tower, heat transfer takes time. Furthermore, the performance of the adsorbent is not improved.

Thus, in the prior art, the target gas component contained in the mixed gas still cannot be efficiently separated, and a proposal for a way to solve this problem has been desired.
Then, the objective of this invention is providing the gas separation method which can isolate | separate the target gas component contained in mixed gas efficiently.

The inventors diligently studied how to solve the above problems. In actual gas separation processing, as described above, in the adsorption process, the adsorbent temperature rises due to the heat of adsorption, even though the lower the adsorbent temperature, the higher the adsorption performance. Although the desorption performance is higher when the temperature of the adsorbent is higher, the temperature of the adsorbent is lowered to absorb the heat of adsorption.
If the heat of adsorption generated in the adsorption tower in the adsorption process can be efficiently transferred to the adsorption tower in the desorption process, the amount of adsorption can be reduced by lowering the temperature of the adsorbent filled in the adsorption tower in the adsorption process. And the temperature of the adsorbent packed in the adsorption tower in the desorption step can be increased to increase the desorption amount.
However, in practice, including the technique described in Patent Document 1, it is practically possible to quickly transfer the heat of adsorption generated in the adsorption process between the different adsorption towers to the adsorbent of the adsorption tower in the desorption process. Have difficulty.
Accordingly, the inventors diligently studied another way of giving the heat of adsorption generated in the adsorption process to the adsorbent of the adsorption tower in the desorption process. As a result, the gas separation chamber has a plurality of adjacent gas separation chambers, the adjacent gas separation chambers are hermetically sealed and partitioned by a partition member that transfers heat between the adjacent gas separation chambers, and target gas components are formed on both surfaces of the partition member. In an adsorption tower having an adsorbent layer that adsorbs the adsorbent layer, an adsorption process in which a mixed gas is brought into contact with the adsorbent layer and the target gas component is adsorbed on the adsorbent layer, and a desorption gas comprising the target gas component adsorbed on the adsorbent layer A desorption step for desorption, and each step is performed in one gas separation chamber of two adjacent gas separation chambers in the adsorption tower, and at the same time, a desorption step is performed in the other gas separation chamber, It has been found that it is effective to alternately repeat the adsorption process and the desorption process, and the present invention has been completed.

That is, the gist of the present invention is as follows.
(1) A method of separating a target gas component from a mixed gas by a pressure swing adsorption method,
It has a plurality of adjacent gas separation chambers, the adjacent gas separation chambers are hermetically sealed and partitioned by a partition member that transfers heat between the adjacent gas separation chambers, and the target gas component is disposed on both surfaces of the partition member. In an adsorption tower having an adsorbent layer to be adsorbed, an adsorption step of bringing the mixed gas into contact with the adsorbent layer and adsorbing the target gas component on the adsorbent layer; and an objective gas component adsorbed on the adsorbent layer A desorption step for desorbing the desorption gas, and performing each adsorption step in one of the two adjacent gas separation chambers in the adsorption tower while simultaneously performing the adsorption step in the other gas separation chamber. The gas separation method according to claim 1, wherein the desorption step is performed and the adsorption step and the desorption step are alternately repeated.

(2) The gas separation method according to (1), wherein the flow rate of the mixed gas introduced in the adsorption step is determined in accordance with the desorption rate of the desorption step.

(3) The gas separation method according to (1), wherein the flow rate of the mixed gas introduced in the adsorption step is controlled so that the temperature change of the gas separation chamber is monitored and the temperature change becomes small.

(4) The gas according to any one of (1) to (3), wherein the partition member is a metal or carbon material plate having a thermal conductivity of 50 W · m ⁻¹ · K ⁻¹ or more. Separation method.

(5) The said adsorbent layer carried the adsorbent on the surface of the layer of the porous material which consists of a metal or a carbon material formed on the said partition member, (1)-(4) characterized by the above-mentioned. The gas separation method according to any one of the above.

(6) The gas separation method according to any one of (1) to (5), wherein the adsorbent layer has a thickness of 50 μm or less.

  According to the present invention, in each of the plurality of gas separation chambers, a step different from the adjacent gas separation chamber among the adsorption step and the desorption step is performed, and the adjacent gas separation chamber has high thermal conductivity. Because it is partitioned by the partition member, the heat of adsorption generated in the adsorption process is quickly transmitted to the adsorbent layer in the adjacent gas separation chamber in the desorption process, thereby efficiently separating the target gas component contained in the mixed gas. Can do.

It is a figure which shows the relationship between the pressure of mixed gas, and the adsorption amount to the adsorption agent of an adsorption gas component. (A) The schematic diagram of the adsorption tower used for the gas separation method which concerns on this invention, (b) It is the process table | surface of the gas separation process in this adsorption tower. It is a figure which shows the partition member which partitions off the inside of the adsorption tower used for the gas separation method which concerns on this invention into a some gas separation chamber. It is a figure which shows an example of the adsorption tower used for the gas separation method which concerns on this invention. It is a figure explaining the structure of the box member laminated body in the adsorption tower used for the gas separation method which concerns on this invention. It is a figure explaining the box member laminated body which has a support body in a gas separation chamber. It is a figure which shows another example of the adsorption tower used for the gas separation method which concerns on this invention. (A) It is a figure explaining the lamination structure of a plate laminated body, and (b) the distribution direction of gas. It is a figure which shows an example of the gas separation apparatus used for the gas separation method which concerns on this invention. It is a figure explaining gas separation operation by the gas separation apparatus used for the gas separation method concerning the present invention. It is a figure explaining gas separation operation by the gas separation apparatus used for the gas separation method concerning the present invention. It is a figure which shows another example of the gas separation apparatus used for the gas separation method which concerns on this invention. It is a figure which shows the temperature change of the adsorption agent in the gas separation method which concerns on invention example 1 of this invention. It is a figure which shows the mixed gas introduction | transduction flow rate in the gas separation method which concerns on the example 2 of this invention. It is a figure which shows the temperature change of the adsorption agent in the gas separation method which concerns on the invention example 2 of this invention. It is a figure which shows the temperature change of the adsorption agent in the gas separation method which concerns on the comparative example of this invention. It is a figure explaining the flow of the adsorption heat between adjacent gas separation chambers.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 2 (a) shows a schematic diagram of an adsorption tower used in the gas separation method according to the present invention, and FIG. 2 (b) shows a process table of gas separation processing in this adsorption tower. The adsorption tower 1 shown in FIG. 2A includes a housing 11 and at least one partition member 12 inside the housing 11, and the partition member 12 includes a plurality of interiors of the housing 11. The gas is divided into gas separation chambers (four gas separation chambers 14a to 14d in the illustrated example). In the adsorption tower 1 according to the present invention, as shown in FIG. 3A, the partition member 12 transfers heat between two gas separation chambers adjacent to the partition member 12, and is adsorbed on both sides of the partition member 12. An agent layer 13 is formed. Then, as shown in the process chart of FIG. 2B, an adsorption process in which the mixed gas is brought into contact with the adsorbent layer 13 to adsorb the target gas component on the adsorbent layer 13, and the target gas adsorbed on the adsorbent layer 13 A desorption step of desorbing a desorption gas composed of components is performed in one gas separation chamber of two adjacent gas separation chambers in the adsorption tower 1 and at the same time the desorption step in the other gas separation chamber And the adsorption process and the desorption process are alternately repeated. As a result, the adsorption tower 1 is a gas adjacent to the gas separation chamber in which one of the two types of gases, the mixed gas supplied in the adsorption process and the desorption gas composed of the target gas component, which is desorbed in the desorption process, is circulated. The separation chamber has two gas flow paths for allowing the other gas to flow. With such a configuration, when the adsorption process is performed in one gas separation chamber (for example, 14a and 14c), the desorption process is performed in the adjacent gas separation chamber (for example, 14b and 14d), and this occurs on the adsorption process side. By transferring the heat of adsorption to the desorption process side through the partition member 12, the temperature increase of the gas separation chamber 14 on the adsorption process side is suppressed and the temperature decrease of the gas separation chambers (for example, 14b and 14d) on the desorption process side is suppressed. be able to.
Although not shown in the figure, a pipe for supplying a mixed gas to each of the gas separation chambers 14a to 14d and exhausting an adsorption off-gas composed of components not adsorbed by the adsorbent layer 13 from the inside of the adsorption tower 1 Automatic valve etc. are connected properly.

The partition member 12 is preferably made of a material having high thermal conductivity, and the thermal conductivity is more preferably 50 W · m ⁻¹ · K ⁻¹ or more. As this partition member 12, a metal and a carbon material can be used, for example.

  As described above, the adsorbent layers 13 made of the adsorbent that adsorbs the target gas component contained in the mixed gas are formed on both surfaces of the partition member 12. Specifically, the formation of the adsorbent layer 13 can be performed by applying or adhering an adsorbent to the surface of the partition member 12. For example, when an adsorbent is applied to both surfaces of the partition member 12, a finely divided adsorbent is slurried with a binder, dried and fired after application. Further, the adsorbent layer 13 can be formed by growing an adsorbent on the partition member 12 by an electrochemical method or a CVD method. As the adsorbent, a known adsorbent such as zeolite may be appropriately selected according to the type of gas to be adsorbed. Since the thermal conductivity of the adsorbent is usually not so high, the thickness of the adsorbent layer 13 is preferably 50 μm or less.

Furthermore, as shown in FIG. 3B, it is more preferable that the porous layer 15 is provided on the surface of the partition member 12, and the adsorbent layer 13 is formed by disposing the adsorbent on the surface of the porous layer 15. Thereby, as shown in FIG. 3C, more adsorbent can be held on the surface of the partition member 12. The porous layer 15 is preferably made of a material having a high surface area and high thermal conductivity. Like the partition member 12, the thermal conductivity is more preferably 50 W · m ⁻¹ · K ⁻¹ or more. . As the porous layer 15, stainless steel, nickel, copper, aluminum, or the like can be used.

  In this invention, in each of several gas separation chamber 14a-14d, it is comprised so that a different process may be performed in an adjacent gas separation chamber among the adsorption | suction process and desorption process of gas separation processing. Therefore, for example, when the adsorption process is performed in the gas separation chamber 14a, the desorption process is performed in the adjacent gas separation chamber 14b. Similarly, an adsorption process is performed at 14c, and a desorption process is performed at 14d. By comprising in this way, the adsorption tower 1 is gas adjacent to the gas separation chamber which distribute | circulates one gas among the mixed gas supplied by an adsorption process, and the desorption gas which consists of a target gas component desorbed by a desorption process. The separation chamber has two gas flow paths through which the other gas flows. Thereby, the heat of adsorption generated in the gas separation chamber in the adsorption process can be quickly transmitted to the adsorbent layer 13 in the adjacent gas separation chamber in the desorption process via the partition member 12 having high thermal conductivity. The target gas component can be efficiently separated from the mixed gas.

  Next, an example of a more specific structure of the adsorption tower used in the gas separation method of the present invention will be shown. In addition, this invention should just have a function equivalent to what is demonstrated here, and is not limited to a specific shape. FIG. 4 is a diagram showing an example of an adsorption tower according to the present invention. Here, FIG. 4A shows a top view of the adsorption tower, and FIG. 4B shows a bird's-eye view. The adsorption tower 2 shown in this figure includes a box member laminated body 22 in which a plurality of rectangular parallelepiped box members are laminated inside a housing 21, and two gases that allow a mixed gas to flow through the box member laminated body 22. It has introduction pipes 23 a and 23 b and two gas discharge pipes 24 a and 24 b for discharging the adsorption off-gas from the box member laminate 22.

  5A and 5B show examples of the shape of the box member laminate 22. In FIG. 5A, the box member 25 has an upper surface 25a, a lower surface 25b, and a pair of opposing side surfaces 25d and 25f made of a plate material, and the other pair of side surfaces 25c and 25e open. In FIG. 5 (b), a pair of side surfaces 25d and 25f are open. The box member laminate 22 includes a plurality of box members 25 having a rectangular parallelepiped shape as shown in FIGS. 5A and 5B, and adjacent portions of the plurality of box members 25 as shown in FIG. 5 (a) and 5 (b) are alternately laminated so that the upper surface 25a and the bottom surface 25b are in close contact with each other, and as shown in FIG. 5 (d), the upper surface 25a and An adsorbent layer 27 is formed by disposing an adsorbent on the surface of the inner side of 25b. Here, at least the upper surface 25a and the bottom surface 25b of the plurality of box members 25 are members that transmit heat, and the pair of the upper surface 25a and the bottom surface 25b in contact with each other forms the partition member 12 shown in FIG. An adsorbent layer 27 is formed on the surface, and corresponds to the adsorbent layer 13 in FIG.

  In addition, two opposing side surfaces (25c and 25e in FIG. 5A and 25d and 25f in FIG. 5B) of the four side surfaces 25c to 25f are open, and one of these openings The mixed gas is introduced into the interior 26, and the adsorption off-gas is discharged from the other side. In the structure shown in FIG. 5A, the mixed gas is introduced from the opening 25c, and the adsorption off-gas is discharged from the opening 25f. The box member laminate 22 is configured such that the opening direction (that is, the direction in which the mixed gas flows) is alternately different between the box members 25 on which the box member laminate 22 is laminated. For example, the box member laminate 22 shown in FIG. 5 (d) is obtained by laminating ten box members 25. When the adsorption process is performed in the interior 26a, the desorption process is performed in the interior 26b. Done. In this way, when the opening directions of the box members 25 are alternately different, the openings of the gas separation chambers on the adsorption side and the desorption side are aligned, and the gas to be circulated can be easily combined into the gas introduction pipe 23 and the gas discharge pipe 24. It becomes. However, without such a laminated structure, the direction of the side surface to be opened is the same for all the box members 25, and the gas flow paths are the same in the interior 26 of every other box member 25 in the lamination direction. You may pipe appropriately on the exterior of the member laminated body 22. FIG.

  The interior 26 of each of the plurality of box members 25 in the adsorption tower 2 of FIG. 4 forms a gas separation chamber 14 in the adsorption tower 1 shown in FIG. In addition, an adsorbent layer 27 is formed on the surface on the inner side 26 of the upper surface 25a and the bottom surface 25b that are in contact with each other adjacent to each other in the stacking direction of the plurality of box members 25, and the pair of the upper surface 25a and the bottom surface 25b is a partition member. Twelve. Here, if the thickness of the box member 25 is large, the amount of adsorbent per volume of the gas separation chamber (the inside 26 of the box member 25) is small and gas separation becomes inefficient, so a large number of thin box members are stacked. Is preferred.

  Such a box member laminate 22 is accommodated in the housing 21 and the sealing member 28 is disposed as shown in FIGS. 4 (a) and 4 (c), thereby introducing a mixed gas from the gas introduction pipe 23b. It is introduced into the inside (for example, 26a) of the box member 25 having an opening facing the pipe 23b side, the target gas component contained in the mixed gas is adsorbed on the adsorbent layer 27, and the gas exhaust pipe 24a faces the gas exhaust pipe side. The target gas component can be separated by desorbing the gas component adsorbed from the adsorbent layer 27 inside the box member 25 having the opening (for example, 26b).

  As described above, in the box member laminated body 22, the direction of the side surface having the opening is configured so that the box members adjacent to each other in the stacking direction of the box member laminated body 22 are different from each other. The mixed gas introduced from one of the tubes 23 (for example, 23a) is introduced into the interior 26 of the box member 25 every other one of the plurality of box members 25 constituting the stacked body 22, in the stacking direction. The mixed gas introduced from the other (for example, 23b) is introduced into the interior 26 of the box member 25 that has not been introduced from one (for example, 23a).

  By having such a configuration, in the adsorption tower 2, it becomes possible to simultaneously perform different processes among the adsorption process and the desorption process in the box members adjacent in the stacking direction. The heat of adsorption generated inside the box member 25 is formed on the surface on the inside 26 side of the upper surface 25a and the lower surface 25b of the adjacent box member 25 in the desorption process via the upper surface 25a and the lower surface 25b constituting the partition member. Therefore, the target gas component can be separated efficiently.

  In the adsorption tower 2, in order to prevent deformation of the box member 25 due to a pressure change in the interior 26 in the adsorption process and the desorption process, a support body that supports the upper surface 25 a of the box member 25 is provided in the interior 26 of the box member 25. The flow path of the mixed gas in the inside 26 of the member 25 can also be held. The number and shape of the supports can be appropriately selected so that the upper surface 25a is supported and the mixed gas flow path can be held. For example, as shown in FIG. 6 (a), a support 29 having a corrugated structure is arranged in the interior 26 of the box member 25 so that the wave direction of the corrugated structure crosses the flow direction of the mixed gas. The adsorption tower 2 shown in b) can be constituted. With this configuration, the deformation of the box member 25 can be prevented without hindering the gas flow. Further, the support 29 is made of a material having high thermal conductivity, and an adsorbent is applied to both sides thereof to form an adsorbent layer, or a porous material having an adsorbent disposed on the surface is attached. May be.

  FIG. 7 is a view showing another example of the adsorption tower used in the gas separation method according to the present invention. The adsorption tower 3 shown in this figure includes a plate stack 32 inside a housing 31, two gas inlets 33 (33 a and 33 b) for supplying a mixed gas to the inside of the adsorption tower 3, and an adsorption tower 3 has two gas discharge ports 34 (34a and 34b) for discharging the adsorption off-gas from the inside.

  As shown in FIGS. 7B and 7C, the plate laminate 32 housed inside the housing 31 is made of a material having high thermal conductivity, and gas circulation holes 35a for flowing gas through the four corners. A rectangular partition plate 35 having ˜35d and an endless belt-like seal member 36 that surrounds two of the four gas flow holes 35a to 35d located diagonally to each other are laminated. Here, the seal member 36 divides a space 37 corresponding to the gas separation chamber in the adsorption tower 1 shown in FIG. 2 between the adjacent partition plates.

  Adsorbent layers 38 are formed on both sides of the partition plate 35. Therefore, the partition plate 35 forms the partition member 12 in the adsorption tower 1 shown in FIG.

  The sealing member 36 surrounds two of the four gas flow holes 35a to 35d that are located diagonally to each other, and between the two partition plates sandwiching the sealing member 36, the adsorption tower shown in FIG. A space 37 forming one gas separation chamber 14 is defined. Here, the pair of two gas flow holes surrounded by the seal member 36 is made different between the gas separation chambers adjacent in the stacking direction. For example, the right seal member 36 on the right partition plate in FIG. 8A surrounds the gas flow holes 35a and 35c, whereas the right seal member on the left partition plate in FIG. 8A. 36 surrounds the gas flow holes 35b and 35d. As a result, as shown in FIG. 8B, the gas flow directions are different in the adjacent spaces 37.

  Such a plate laminated body 32 is accommodated in the housing 31, and the gas inlets 33a and 33b are connected to the four gas circulation holes 35a and 35b of the uppermost partition plate 35, respectively. By connecting the gas outlets 34a and 34b to the gas outlets 34a and 34b, the mixed gas introduced from the gas inlet 33 (for example, 33a) is introduced into the space 37 through the gas flow holes (for example, 35a) of the partition plate 35. The target gas component contained in the mixed gas is adsorbed to the adsorbent layer 38 disposed on the surface of the partition plate 35, and the adsorption off-gas is supplied to the gas discharge port 34 (for example, 34a) through the gas flow hole (for example, 35c). The target gas component contained in the mixed gas can be separated by discharging to the outside.

  More specifically, in the plate laminated body 32, the two gas introduction ports 33 are configured such that the pair of gas flow holes surrounded by the seal member 36 are different from each other between the gas separation chambers adjacent in the lamination direction. The mixed gas introduced from one (for example, 33a) is introduced into every other space 37 in the stacking direction among the plurality of spaces 37 partitioned by the partition plate 35 and the seal member 36, and the other ( For example, the mixed gas introduced from 33b) is introduced into the space 37 that was not introduced from one side (for example, 33a).

  By having such a configuration, in the adsorption tower 3, it becomes possible to simultaneously perform different processes among the adsorption process and the desorption process in the box members adjacent in the stacking direction. The heat of adsorption generated inside the space 37 can be transmitted via the partition plate 35 to the adsorbent layer 38 formed on the surface of the adjacent space 37 in the desorption process, and is included in the mixed gas. Gas components can be separated efficiently.

  By using the above adsorption tower, the temperature increase of the adsorption agent on the adsorption side and the temperature decrease on the desorption side can be suppressed, and the target gas component can be efficiently separated from the mixed gas.

Then, the gas separation apparatus used for the gas separation method according to this invention is demonstrated. FIG. 9 is a diagram showing an example of a gas separation device according to the present invention. The device 50 is a gas separation apparatus having an adsorption tower 2 shown in FIG. 4 as an adsorption tower 52, and supplies the mixed gas G ₀ in the adsorption tower 52, an air blowing means 51 such as a blower or compressor pumps, suction And an exhaust means 53 such as a vacuum pump for desorbing and collecting the gas component adsorbed on the agent layer 27. Further, the mixed gas G ₀ from the gas inlet pipe 23a and 23b is introduced into the adsorption tower, the gas exhaust pipe 24a and 24b, to allow adsorption offgas exhaust a gas not adsorbed by the adsorbent layer 27, the pipe The automatic valves AV1 to AV6 and the back pressure valve BPV are configured.

A gas separation operation using the apparatus 50 will be described with reference to FIGS. First, referring to FIG. 10, the mixed gas G ₀ is blown by the blowing means 51 is caused to flow through the inside (gas separation chamber) 26 of the adsorption tower 52 through an automatic valve AV1. The pressure at this time of the gas is controlled by a back pressure valve BPV downstream of automatic valve AV3, nonadsorbed component gas at a constant pressure or more was not adsorbed by the adsorbent layer 27 are discharged as an adsorption offgas G _1.

Simultaneously, gas components adsorbed on the adsorbent layer 27 through an automatic valve AV5 is desorbed and discharged as a desorption gas G ₂ consisting of target gas component by the exhaust means 53. At this time, the heat of the adsorbent layer 27 in the gas separation chamber in the adsorption process is transferred to the adsorbent layer 27 in the adjacent gas separation chamber in the desorption process through the upper surface 25a and the lower surface 25b of the adjacent box member 25. Is done.

When the gas component is adsorbed to some extent on the adsorbent layer 27 in the gas separation chamber in the adsorption process and the performance deteriorates, the opening and closing of the valve is switched from FIG. 10 to FIG. In FIG. 11, the mixed gas G ₀ is blown by the blowing means 1 and is circulated into the gas separation chamber of the adsorption tower 52 via the automatic valve AV 4. The pressure at this time of the gas is controlled by a back pressure valve BPV downstream of automatic valve AV3, nonadsorbed component gas at a constant pressure or more was not adsorbed by the adsorbent is discharged as an adsorption offgas G _1.

At the same time, gas components adsorbed on the adsorbent layer 27 are discharged as a desorption gas G ₂ are desorbed through the automatic valve AV2 by the exhaust means 53. At this time, the adsorption heat of the gas separation chamber in the adsorption process is transmitted to the adsorbent layer 27 in the adjacent gas separation chamber in the desorption process via the upper surface 25a and the lower surface 25b of the box member 25.

  In this way, in each of the plurality of gas separation chambers constituting the gas separation device, among the adsorption step and the desorption step, steps different from the adjacent gas separation chambers can be performed simultaneously, and the gas separation in the adsorption step The adsorption heat generated in the chamber can be transmitted to the adsorbent layer of the gas separation chamber in the desorption process through the partition member, so that the target gas component can be efficiently separated from the mixed gas.

10 and 11, the flow rate for introducing the mixed gas G ₀ into the adsorption tower 52 is determined by the ability of the blowing means 51, and similarly, the flow rate of the desorption gas G ₂ is determined by the ability of the exhaust means 53. Therefore, when the amount of the adsorbed gas component contained in the mixed gas G ₀ in the gas separation chamber in the adsorption step is not the same as the amount of the adsorbed gas component desorbed in the gas separation chamber in the desorption step. Since the amount of heat generated by adsorption and the amount of heat removed by desorption do not match, the temperature of the adsorbent may change.

  When the temperature change width is increased, in the gas separation chamber in the adsorption process, the ratio of the adsorbed gas component that passes through the adsorption tower without being adsorbed by the adsorbent when the temperature is high increases, so that the separation efficiency decreases. Further, in the gas separation chamber in the desorption process, when the temperature is lowered, the desorption speed of the adsorbed gas component is decreased and the separation efficiency is similarly decreased.

  Therefore, if the flow rate of the mixed gas, which is a raw material introduced into the adsorption tower in the adsorption step, can be changed according to the desorption speed in the adjacent gas separation chamber, it is possible to further suppress the temperature change in the gas separation chamber. is there. The temperature change behavior changes depending on the conditions such as the adsorbent performance, gas flow rate, and pressure in the gas separation chamber in the desorption process, so the mixed gas flow rate introduced in the adsorption process in accordance with the desorption process conditions (desorption speed) Should be determined.

FIG. 12 shows a separation apparatus used in the gas separation method of the present invention that suppresses the temperature change by changing the flow rate of the mixed gas. In this apparatus 60, the mixed gas G ₀ is introduced into the adsorption tower 62 through the automatic valve AV1 or AV4 by blowing means 61, provided with a flow meter F1 and F4 between the respective automatic valve and the adsorption tower ing. Since the flow rate of the mixed gas can be changed depending on the opening degree of the automatic valves AV1 and AV4, the opening degree of the automatic valve is set to be large and the flow rate of the mixed gas is increased by a program when the desorption speed is high. When the desorption speed is low, the opening of the automatic valve is set to a small value to reduce the flow rate of the mixed gas, and if the flow rate of the mixed gas is set to change with time, the temperature change in the adsorption process can be further suppressed. Is possible.

  More specifically, first, after performing the adsorption and desorption processes under the condition that the flow rate of the mixed gas is constant to obtain a temperature fluctuation profile, the flow rate is suppressed in a time zone in which the temperature tends to increase, The adsorption and desorption processes are carried out by setting the flow rate to be increased in the time zone that tends to decrease. Since the temperature profile changes accordingly, it is desirable to repeat the same adjustment and set the temperature fluctuation to be more stable.

  It is also possible to incorporate a program so that these adjustments are performed automatically.

  Examples of the present invention will be described below to show the effects of the present invention. The scope of the present invention is not limited by the following examples.

(Invention Example 1)
A box-shaped stainless steel container (inner side is 25 cm long x 25 cm wide x 2 cm high) molded with a metal with a thickness of 1 mm, and a porous material prepared by molding and sintering a mixture of stainless steel particles and resin particles Prepare metal plates (length 25 cm x width 25 cm x thickness 0.7 cm, specific gravity: 0.7 g / cm ³ , surface area / volume ratio: 10000 m ⁻¹ , pore diameter: 200 μm), and porous metal on both upper and lower surfaces of a metal container I stuck the board. As shown in FIG. 5 (d), 10 layers were laminated so that the side surfaces having openings, that is, the gas flow directions were orthogonal to each other. The laminate is immersed in an aqueous solution in which finely pulverized Na-substituted Y-type zeolite powder is suspended together with a binder, and is applied to the inside (gas separation chamber) of a metal container constituting the laminate. After removing the applied adsorbent, it was dried at 200 ° C. for 5 hours and calcined at 300 ° C. for 24 hours. From the weight change of the laminate before and after the zeolite application, the amount of the adsorbent applied to the inside of the metal container constituting the laminate was 267 g, and the average coating thickness calculated from this was 47 μm.

Using a gas separation device manufactured as described above, the carbon dioxide from a mixed gas (CO ₂₎ was treated to separate gas. At that time, as the mixed gas, a gas having a composition of CO ₂ : 22% by volume and N ₂ : 78% by volume is used, and in each of the plurality of gas separation chambers, the adjacent gas among the adsorption process and the desorption process. The process of separating the CO ₂ gas from the mixed gas was performed by controlling the gas flow with an automatic valve so that a process different from the separation chamber was performed. The mixed gas was circulated in the adsorption tower at 7 mol / kg-adsorbent / 100 sec, the back pressure valve was adjusted so that the pressure on the adsorption side was 200 kPa, and the pressure on the desorption side was reduced to 5 kPa with a vacuum pump. . Further, the temperature change during the gas separation operation was also measured by inserting a thermocouple from the gas inlet of the adsorption tower vessel so as to be able to measure the temperature change of the adsorbent and contacting the adsorbent. The temperature change showed periodic behavior. The temperature change is shown in FIG. The horizontal axis of the graph represents the process start time of 0 sec. The temperature varied between 22 and 28 ° C., and the adsorption rate was higher than the desorption rate at 0 to 40 sec / 100 to 140 sec. On the other hand, since the adsorption rate was lower than the desorption rate at 40 to 70 sec / 140 to 170 sec, the temperature showed a downward trend. At 70 to 100 sec / 170 to 200 sec, the adsorption rate and the desorption rate are almost balanced, but since the desorption rate gradually decreases, the temperature gradually increased from gradually decreasing. The overall temperature change width was 6 ° C. On the exhaust side of the vacuum pump, 99% by volume CO ₂ gas was obtained with a recovery rate of 72%.

(Invention Example 2)
Using the gas separation apparatus of the invention example, using a mixed gas of the same composition, and introducing the mixed gas into the adsorption tower at the constant flow rate in the invention example 1 as shown in FIG. As described above, the flow rate was changed from 0.15 for the time 0 to 40 seconds, 2.3 for the flow rate 40 to 70 seconds, and 1 for the flow rate 70 to 100 seconds. The temperature change is shown in FIG. On the horizontal axis of the graph, the start time of the adsorption process was 0 sec. The temperature varied between 24.5 and 25.5 ° C, and the temperature change width was 1.0 ° C. CO ₂ gas 99 vol% concentration was obtained at 75% recovery.

(Comparative example)
Using the gas separation device of the invention example, using a mixed gas of the same composition, and controlling the gas flow with an automatic valve so that the same process is performed in all gas separation chambers, the CO ₂ gas is separated from the mixed gas The process to do. In addition, the flow rate of the mixed gas, which is the raw material, and the pressure in the adsorption and desorption processes were set to the same conditions as in the above invention examples. As a result, the temperature change is shown in FIG. On the horizontal axis of the graph, the start time of the adsorption process was 0 sec. 0 to 100 sec corresponds to the adsorption step, and the mixed gas is introduced into the gas separation device at a constant flow rate. And since the amount of gas adsorbed to the adsorbent is also adsorbed to the adsorbent according to the ratio of the adsorbed gas in the mixed gas, the generation of heat of adsorption becomes almost constant throughout the adsorption process, as shown in the time of FIG. The temperature rose linearly. On the other hand, in the desorption process of 100 to 200 sec, the gas in the gas separation chamber is exhausted by the exhaust means, and the amount of the desorbed gas changes as the pressure in the gas separation chamber decreases. The desorption process is 100 to 200 sec. However, in 100 to 140 sec, the gas remaining in the gas separation chamber is exhausted, and the amount of desorbed gas is not so much until the pressure in the gas separation chamber is reduced to some extent. In 140 to 170 sec, the amount of gas to be desorbed is the largest, and in 170 to 200 sec, the amount of gas to be desorbed gradually decreases. Therefore, the temperature change accompanying the endotherm due to the desorption of the gas component tended to decrease in a non-linear manner such as the time of 100 to 200 sec in FIG. As a result, the temperature changed between 19 and 31 ° C., and the temperature change width was 12 ° C. 99 volume% concentration of CO ₂ gas was obtained with a recovery rate of 58%. Thus, it can be seen that the temperature recovery is suppressed by the present invention, whereby the gas recovery rate is improved, and a predetermined gas component can be efficiently separated from the mixed gas.

1, 2, 3, 52, 62 Adsorption towers 11, 21, 31 Housing 12 Partition members 13, 27, 38 Adsorbents 14, 14a, 14b, 14c, 14d Gas separation chamber 15 Porous layer 22 Box member laminate 23 , 23a, 23b Gas introduction pipes 24, 24a, 24b Gas discharge pipe 25 Box member 25a Upper surface 25b Lower surface 25c, 25d, 25e, 25f Side surface 26 Inner 28, 36 Seal member 29 Support body 32 Plate laminate 33, 33a, 33b Gas Inlet 34, 34a, 34b Gas outlet 35 Partition plates 35a, 35b, 35c, 35d Gas flow hole 37 Space 50, 60 Gas separators 51, 61 Blowing means 53, 63 Exhaust means 101 Adsorbed gas molecules G ₀ Mixed gas G ₁ Adsorption off gas G ₂ Desorption gas AV1, AV2, AV3, AV4, AV5, AV6 Automatic valve F1, F4 Flow meter B VP back pressure valve

Claims (6)

  When separating the target gas component from the mixed gas by the pressure swing adsorption method, an adsorption step of bringing the mixed gas into contact with the adsorbent layer and adsorbing the target gas component to the adsorbent layer; adsorbing to the adsorbent layer And a desorption step of desorbing a desorption gas composed of a target gas component, wherein the desorption step has a plurality of adjacent gas separation chambers, the adjacent gas separation chambers are airtight and the adjacent gas In an adsorption tower partitioned by a partition member that transfers heat between the separation chambers and having an adsorbent layer that adsorbs the target gas component on both surfaces of the partition member, one of the two adjacent gas separation chambers is separated by gas At the same time as performing the adsorption step in the chamber, the desorption step is performed in the other gas separation chamber, and heat is transferred from the adsorption step side to the desorption step side through the partition member. Gas separation method characterized by suppression of temperature reduction in the temperature rise and the desorption step side of the adsorbent layer of the adsorbent layer.   The gas separation method according to claim 1, wherein a flow rate of the mixed gas introduced in the adsorption step is determined in accordance with a desorption rate in the desorption step.   The gas separation method according to claim 1, wherein the flow rate of the mixed gas introduced in the adsorption step is controlled so that the temperature change becomes small by monitoring the temperature change in the gas separation chamber. The gas separation method according to claim 1, wherein the partition member is a metal or carbon material plate having a thermal conductivity of 50 W · m ⁻¹ · K ⁻¹ or more.   The said adsorbent layer carry | supported the adsorbent on the surface of the layer of the porous material which consists of a metal or a carbon material and was formed on the said partition member. Gas separation method. The gas separation method according to claim 1, wherein the adsorbent layer has a thickness of 50 μm or less.

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