Reactor and gas recovery device

Abstract

The present invention provides a reactor comprising a plurality of square-column honeycomb structures 10 having outer perimeter walls 11 and partition walls 15 laid out on the inner side of the outer perimeter walls 11 to partition, and thus form, a plurality of cells 14 which extend from an inlet end face 12 to an outlet end face 13 and which allow circulation of a process gas containing a gas to be trapped, wherein the outer perimeter walls 11 parallel to the direction in which the cells 14 of the plurality of square-column honeycomb structures 10 extend are arranged to be in direct or indirect contact with each other. In a cross section orthogonal to the direction in which the cells 14 extend, a peripheral region surrounding one or more square-column honeycomb structures 10 located in a central region C has one or more square-column honeycomb structures 10 that undergo less pressure loss when the process gas is circulated through the one or more square-column honeycomb structures 10 as compared to the one or more square-column honeycomb structures 10 in the central region C.

Description

Reactor and gas recovery device

[0001] The present invention relates to a reactor and a gas recovery device.

[0002] As a measure to combat global warming, there is a growing demand for the capture of CO2 from factory exhaust gases and combustion exhaust gases from CO2 emission sources such as thermal power plants, as well as the direct capture and fixation of CO2 from the atmosphere (direct air capture: DAC), and the effective use of captured CO2 through methanation, etc.

[0003] The main methods proposed for CO2 capture include adsorbing CO2 onto an adsorbent capable of adsorbing CO2, releasing the CO2 by varying the temperature, pressure, humidity, etc., and capturing it as highly concentrated CO2, which can then be used as a raw material for the chemical industry, or injected underground for immobilization. Adsorbents are used by being supported on porous pellets, porous particles, fiber filters, honeycomb structures, etc. (e.g., Non-Patent Document 1).

[0004] "Cost and Evaluation of Direct Air Capture (DAC) Method for Carbon Dioxide (Vol. 2) - Adsorption Separation Process -", ​​Japan Science and Technology Agency, Low Carbon Society Strategy Center, March 2021

[0005] In Non-Patent Document 1, the thickness of the partition wall is 0.15 mm, and the cell density is 400 cells / inch. 2 (62 pieces / cm 2The publication also describes a reactor in which an adsorbent is supported (an adsorbent layer is formed) on the surface of the partition walls of a honeycomb structure made of mullite and having an opening ratio of 75.0%. However, in such a honeycomb structure with a simple structure, in a cross section perpendicular to the cell extension direction, gas containing CO2 flows easily through the cells in the central region (i.e., the flow rate of gas flowing through the cells in the central region is high), but it does not flow easily through the cells in the peripheral region (i.e., the flow rate of gas flowing through the cells in the peripheral region is low). Therefore, the CO2 recovery rate and amount by the adsorbent supported on the partition walls that define the cells in the peripheral region are lower than those by the adsorbent supported on the partition walls that define the cells in the central region. Furthermore, while adsorbents gradually deteriorate due to repeated CO2 adsorption and desorption, the adsorbent supported on the partition walls that define the cells in the central region deteriorates more quickly than the adsorbent supported on the partition walls that define the cells in the peripheral region, resulting in a shorter lifespan of the reactor.

[0006] The above-described phenomenon becomes a problem particularly when the diameter of the honeycomb structure is increased or in a reactor in which a plurality of honeycomb structures are arranged in a direction perpendicular to the extension direction of the cells of the honeycomb structure. Note that, although the above description has been given using an example of a reactor in which the target gas to be captured is CO2 and an adsorbent capable of adsorbing CO2 is used, the same problem as above can also occur in a reactor in which the target gas to be captured is a gas other than CO2 and a functional material other than an adsorbent capable of adsorbing CO2 is used.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a reactor and a gas recovery device that allows a processing gas containing a gas to be captured to easily flow into the cells of the square pillar-shaped honeycomb structure in the peripheral region, thereby increasing the amount of gas to be captured and extending its lifespan.

[0008] The present inventors have conducted extensive research into a reactor in which a plurality of square pillar-shaped honeycomb structures located in a peripheral region are arranged around one or more square pillar-shaped honeycomb structures located in a central region, and as a result, have found that the above-mentioned problems can be solved by configuring the square pillar-shaped honeycomb structures in the peripheral region to have a portion where the pressure loss of the square pillar-shaped honeycomb structures in the central region is smaller than the pressure loss of the square pillar-shaped honeycomb structures in the central region, thereby completing the present invention. That is, the present invention is exemplified as follows.

[0009] [1] A reactor comprising a plurality of quadrangular pillar-shaped honeycomb structures each having an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells extending from an inflow end face to an outflow end face through which a process gas containing a target gas to be captured can flow, the reactor being arranged so that the outer peripheral walls of the plurality of quadrangular pillar-shaped honeycomb structures, which are parallel to the direction in which the cells extend, are in direct or indirect contact with each other, and the reactor has one or more quadrangular pillar-shaped honeycomb structures in an outer peripheral region around one or more of the quadrangular pillar-shaped honeycomb structures located in a central region in a cross section perpendicular to the direction in which the cells extend, such that the pressure loss when the process gas is caused to flow through the quadrangular pillar-shaped honeycomb structures is smaller than that of the quadrangular pillar-shaped honeycomb structures in the central region.

[0010] [2] The reactor according to [1], wherein the reactor has, in the outer peripheral region, one or more of the quadrangular pillar-shaped honeycomb structures, such that, when measuring the distance from the center of the reactor to the axial center of the quadrangular pillar-shaped honeycomb structure in a cross section perpendicular to the extension direction of the cells, the pressure loss of the quadrangular pillar-shaped honeycomb structure at a position where the distance is long is equal to or smaller than the pressure loss of the quadrangular pillar-shaped honeycomb structure at a position where the distance is short.

[0011] [3] The reactor according to [1], wherein, in a cross section perpendicular to the cell extension direction, the quadrangular pillar-shaped honeycomb structure located at or closest to the center of the reactor is defined as a first group, the quadrangular pillar-shaped honeycomb structures arranged around the first group are defined as a second group, and the quadrangular pillar-shaped honeycomb structures arranged around groups 2 and above are defined as a 2+n group (n is 1 or more), in that order, in a region of the second group or above, the reactor has one or more quadrangular pillar-shaped honeycomb structures having a larger group number, the pressure loss of the quadrangular pillar-shaped honeycomb structure being equal to or smaller than the pressure loss of the quadrangular pillar-shaped honeycomb structure having a smaller group number.

[0012] [4] The reactor according to [1], wherein, in a cross section perpendicular to the cell extension direction, the quadrangular pillar-shaped honeycomb structure located at or closest to the center of the reactor is defined as a first group, the quadrangular pillar-shaped honeycomb structures arranged around the first group and having the same pressure loss are defined as a second group, and the quadrangular pillar-shaped honeycomb structures arranged around the second group or more and having the same pressure loss are defined as a 2+n group (n is 1 or more), in which in a region of the second group or more, the pressure loss of the quadrangular pillar-shaped honeycomb structure having a larger group number is equal to or smaller than the pressure loss of the quadrangular pillar-shaped honeycomb structure having a smaller group number.

[0013] [5] The reactor according to any one of [1] to [4], wherein all of the rectangular pillar-shaped honeycomb structures in the reactor have the same outer dimensions.

[0014] [6] The reactor according to [5], wherein, in a cross section perpendicular to the cell extension direction, among the plurality of quadrangular pillar-shaped honeycomb structures positioned at the outermost periphery of the reactor, the pressure loss of the quadrangular pillar-shaped honeycomb structures positioned at corner portions is smaller than the pressure loss of the quadrangular pillar-shaped honeycomb structures positioned other than at the corner portions.

[0015] [7] The reactor according to any one of [1] to [6], wherein the pressure loss of the quadrangular pillar-shaped honeycomb structure is controlled by the size of the cell density of the quadrangular pillar-shaped honeycomb structure and / or the thickness of the partition wall.

[0016] [8] The reactor according to [7], wherein the ratio of the cell density of the rectangular pillar-shaped honeycomb structure in the central region to the cell density of the rectangular pillar-shaped honeycomb structure in the peripheral region is more than 1.00 and less than 6.00.

[0017] [9] The reactor according to [7], wherein the ratio of the cell density of the quadrangular pillar honeycomb structure in the central region to the cell density of the quadrangular pillar honeycomb structure in the peripheral region is 0.16 to 1.00, and the ratio of the thickness of the partition walls of the quadrangular pillar honeycomb structure in the central region to the thickness of the partition walls of the quadrangular pillar honeycomb structure in the peripheral region is more than 1.00 and less than 6.00.

[0018]

[10] The reactor according to any one of [1] to [9], wherein at least a part of the quadrangular pillar-shaped honeycomb structure has plugging portions in the cells on the inflow end face side and / or the outflow end face side, and the porosity of the plugging portions in the quadrangular pillar-shaped honeycomb structure in the central region is smaller than the porosity of the plugging portions in the quadrangular pillar-shaped honeycomb structure in the peripheral region.

[0019]

[11] The reactor according to

[10] , wherein a ratio of the porosity of the plugging portions in the quadrangular pillar-shaped honeycomb structure in the central region to the porosity of the plugging portions in the quadrangular pillar-shaped honeycomb structure in the peripheral region is 0.11 or more and less than 1.00.

[0020]

[12] The reactor according to any one of [1] to

[11] , wherein at least a part of the quadrangular pillar-shaped honeycomb structure has plugging portions in the cells on the inflow end face side and / or the outflow end face side, and a ratio of cells having the plugging portions in the quadrangular pillar-shaped honeycomb structure in the central region is higher than a ratio of cells having the plugging portions in the quadrangular pillar-shaped honeycomb structure in the peripheral region.

[0021]

[13] The reactor according to

[12] , wherein a ratio of a proportion of cells having the plugging portions in the quadrangular pillar-shaped honeycomb structure in the peripheral region to a proportion of cells having the plugging portions in the quadrangular pillar-shaped honeycomb structure in the central region is less than 1.00.

[0022]

[14] The reactor according to any one of [1] to

[13] , wherein the shape of the cells is quadrangular or hexagonal in a cross section perpendicular to the extension direction of the cells.

[0023]

[15] The reactor according to any one of [1] to

[14] , wherein the length of the quadrangular pillar honeycomb structure in the cell extension direction is 10 to 200 mm.

[0024]

[16] The reactor according to any one of [1] to

[15] , wherein the rectangular pillar-shaped honeycomb structure is mainly composed of one or more selected from cordierite, mullite, alumina, silica, silicon carbide, and Si-bonded silicon carbide.

[0025]

[17] The reactor according to any one of [1] to

[16] , wherein the porosity of the partition walls is 30% or more and less than 80%.

[0026]

[18] The reactor according to any one of [1] to

[17] , wherein the partition walls have an average pore diameter of 10 to 300 μm.

[0027]

[19] The reactor according to any one of [1] to

[18] , further comprising a functional material supported on the partition wall.

[0028]

[20] The reactor according to

[19] , wherein the functional material is an amine compound and / or a metal organic framework.

[0029]

[21] The reactor according to any one of [1] to

[20] , further comprising a cylindrical member that accommodates the quadrangular pillar-shaped honeycomb structure.

[0030]

[22] A gas recovery device for adsorbing and releasing a target gas contained in a process gas, the gas recovery device comprising: the reactor according to any one of [1] to

[21] ; a heating unit capable of heating the reactor; a gas supply pipe capable of supplying the process gas or a purge gas to an inlet of the reactor; and a gas discharge pipe capable of discharging the process gas or the purge gas from an outlet of the reactor.

[0031]

[23] The gas recovery apparatus according to

[22] , wherein the gas supply pipe has a gas supply branch pipe branched into two, the gas supply branch pipe being a first gas supply branch pipe capable of supplying the processing gas and a second gas supply branch pipe capable of supplying the purge gas; the gas exhaust pipe has a gas exhaust branch pipe branched into two, the gas exhaust branch pipe being a first gas exhaust branch pipe capable of exhausting the processing gas and a second gas exhaust branch pipe capable of exhausting the purge gas; and the gas recovery apparatus further comprises a supply gas switching valve capable of blocking the first gas supply branch pipe or the second gas supply branch pipe, and an exhaust gas switching valve capable of blocking the first gas exhaust branch pipe or the second gas exhaust branch pipe.

[0032] According to the present invention, it is possible to provide a reactor and a gas recovery device in which the processing gas containing the target gas to be captured can easily flow into the cells of the rectangular pillar-shaped honeycomb structure in the peripheral region, thereby increasing the amount of target gas recovered and extending the life of the reactor and gas recovery device.

[0033] 3A is a schematic diagram for explaining the arrangement of a plurality of quadrangular pillar-shaped honeycomb structures constituting a reactor according to one embodiment of the present invention. FIG. 3B is a schematic diagram for explaining the arrangement of a plurality of quadrangular pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 3C is a schematic diagram for explaining the arrangement of a plurality of quadrangular pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 3D is a schematic diagram for explaining the arrangement of a plurality of quadrangular pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 3E is a schematic diagram for explaining the arrangement of a plurality of quadrangular pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. 9A is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9B is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9C is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9D is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9E is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9F is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 9G is a schematic view illustrating the arrangement of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention.1 is a schematic diagram showing the configuration of a gas recovery device according to an embodiment of the present invention.

[0034] The reactor of the present invention includes a plurality of square pillar-shaped honeycomb structures, each having an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells extending from an inlet end face to an outlet end face through which a process gas containing a target gas to be captured can flow. The plurality of square pillar-shaped honeycomb structures are arranged so that the outer peripheral walls parallel to the cell extension direction of the plurality of square pillar-shaped honeycomb structures are in direct or indirect contact with each other. Furthermore, in a cross section perpendicular to the cell extension direction, the reactor includes one or more square pillar-shaped honeycomb structures in a peripheral region surrounding one or more square pillar-shaped honeycomb structures located in a central region, the pressure loss of which when a process gas is circulated through the square pillar-shaped honeycomb structure is smaller than that of the square pillar-shaped honeycomb structure in the central region. This configuration allows the process gas containing the target gas to be captured to easily flow through the cells of the square pillar-shaped honeycomb structures in the peripheral region in a cross section perpendicular to the cell extension direction, thereby increasing the recovery amount of the target gas to be captured and extending the reactor's lifespan. Furthermore, when a functional material is supported on the rectangular pillar-shaped honeycomb structure of a reactor having such a structure, the difference in the amount of captured gas recovered between the central region and the peripheral region becomes smaller, thereby preventing the functional material in the central region from deteriorating prematurely compared to the peripheral region, and also reducing the amount of heat required when releasing (desorbing) the captured gas.

[0035] The gas recovery device of the present invention is for adsorbing and releasing a target gas contained in a process gas, and includes the above-mentioned reactor, a heating unit capable of heating the reactor, a gas supply pipe capable of supplying a target gas or a purge gas to the inlet of the reactor, and a gas discharge pipe capable of discharging the target gas or the purge gas from the outlet of the reactor. With this configuration, the gas recovery device of the present invention uses a reactor that can increase the amount of target gas recovered and extend its life, thereby maintaining good gas recovery performance over a long period of time. Furthermore, the amount of heat required to release (desorb) the target gas from the reactor can be reduced, thereby reducing operating costs.

[0036] Hereinafter, embodiments of the reactor and gas recovery device of the present invention will be described in detail with reference to the drawings. The reactor and gas recovery device of the present invention are not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0037] <Reactor> The reactor according to the embodiment of the present invention can be suitably used to recover a target gas to be captured contained in a process gas. The target gas is not particularly limited, but examples thereof include exhaust gases emitted from factories, power plants, etc., and the atmosphere. The exhaust gas is not particularly limited, but examples thereof include combustion exhaust gases generated when burning fossil fuels, coal gasification gas obtained by gasifying coal, and natural gas in thermal power plants, steelworks, etc. Furthermore, the target gas to be captured is not particularly limited, but examples thereof include carbon dioxide (CO2), nitrogen oxides (NO x ), sulfur oxides (SO x Among these, the reactor according to the embodiment of the present invention is particularly useful for recovering carbon dioxide (CO2) contained in combustion exhaust gas and the atmosphere.

[0038] FIG. 1 is a schematic diagram (schematic diagram of a cross section perpendicular to the cell extension direction of the square pillar-shaped honeycomb structure) for explaining the arrangement of a plurality of square pillar-shaped honeycomb structures constituting a reactor according to one embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the arrangement of a plurality of square pillar-shaped honeycomb structures constituting a reactor according to another embodiment of the present invention. FIG. 3A is a schematic diagram of a cross section perpendicular to the cell extension direction of one square pillar-shaped honeycomb structure, and FIG. 3B is a schematic diagram of a cross section taken along line a-a' of the square pillar-shaped honeycomb structure of FIG. 3A (schematic diagram of a cross section parallel to the cell extension direction). The reactor shown in FIGS. 1 and 2 is composed of a plurality of square pillar-shaped honeycomb structures 10 (10a, 10b). 2A and 2B , one rectangular pillar-shaped honeycomb structure 10 constituting the reactor has an outer peripheral wall 11 and partition walls 15 disposed inside the outer peripheral wall 11 and defining a plurality of cells 14 extending from an inlet end face 12 to an outlet end face 13. A process gas containing a target gas to be captured can flow through the cells 14.

[0039] 1 and 2, a plurality of square pillar-shaped honeycomb structures 10 are arranged so that the peripheral walls 11 parallel to the extension direction of the cells 14 are in direct or indirect contact with each other. When the peripheral walls 11 are in indirect contact with each other, a bonding layer, a spacer, or the like can be provided between the opposing peripheral walls 11.

[0040] The reactor shown in Fig. 1 has, in a cross section perpendicular to the extension direction of the cells 14, one or more quadrangular pillar-shaped honeycomb structures 10 (10b) in an outer peripheral region around one quadrangular pillar-shaped honeycomb structure 10 (10a) located in a central region C, such that the pressure loss when a process gas is caused to flow through the quadrangular pillar-shaped honeycomb structures 10 (10a, 10b) is smaller than that of the quadrangular pillar-shaped honeycomb structure 10 (10a) in the central region C. Furthermore, the reactor shown in Fig. 2 has, in a cross section perpendicular to the extension direction of the cells 14, one or more quadrangular pillar-shaped honeycomb structures 10 (10b) in an outer peripheral region around a plurality (four) quadrangular pillar-shaped honeycomb structures 10 (10a) located in the central region C, such that the pressure loss when a process gas is caused to flow through the quadrangular pillar-shaped honeycomb structures 10 (10a, 10b) is smaller than that of the quadrangular pillar-shaped honeycomb structure 10 (10a) in the central region C. That is, in the reactor shown in FIGS. 1 and 2 , the pressure loss of at least a portion of the square pillar-shaped honeycomb structures 10 (10b) in the peripheral region is configured to be smaller than the pressure loss of the square pillar-shaped honeycomb structures 10 (10a) in the central region C. This configuration facilitates the flow of process gas through the square pillar-shaped honeycomb structures 10 (10b) in the peripheral region, thereby reducing the difference in process gas flow rate between the square pillar-shaped honeycomb structures 10 (10a) in the central region C and the square pillar-shaped honeycomb structures 10 (10b) in the peripheral region. In FIGS. 1 and 2 , identical hatched areas represent areas having the same pressure loss. This also applies to other schematic diagrams illustrating the arrangement of multiple square pillar-shaped honeycomb structures 10. In this specification, the term "same pressure loss" means that the difference in pressure loss is within ±5%.

[0041] Here, in this specification, the central region C means a region formed of one quadrangular pillar-shaped honeycomb structure 10 (10a) located at the center P1 of the reactor or a region formed of a plurality of quadrangular pillar-shaped honeycomb structures 10 (10a) closest to the center P1 of the reactor in a cross section perpendicular to the extension direction of the cells 14 of the reactor formed of a plurality of quadrangular pillar-shaped honeycomb structures 10. Further, the peripheral region means a region other than the central region C in the cross section.

[0042] The pressure losses of the plurality of square pillar-shaped honeycomb structures 10 (10b) in the peripheral region may all be the same or different. However, as shown in FIGS. 1 and 2, when the pressure losses of the plurality of square pillar-shaped honeycomb structures 10 (10b) in the peripheral region are all the same, the pressure losses of all of the plurality of square pillar-shaped honeycomb structures 10 (10b) in the peripheral region are smaller than the pressure loss of the square pillar-shaped honeycomb structures 10 a in the central region C. Furthermore, the plurality of square pillar-shaped honeycomb structures 10 (10b) in the peripheral region may have at least one square pillar-shaped honeycomb structure 10 (10b) having a smaller pressure loss than the square pillar-shaped honeycomb structure 10 (10a) in the central region C, and may also have some square pillar-shaped honeycomb structures 10 (10b) having the same pressure loss as the square pillar-shaped honeycomb structure 10 (10a) in the central region C. Here, an example of a reactor having such a structure is shown in FIGS. 4A to 4H. 4A to 4H, the square pillar-shaped honeycomb structures 10 in the peripheral region may be composed of square pillar-shaped honeycomb structures 10a having the same pressure loss as the square pillar-shaped honeycomb structures 10a in the central region C, and square pillar-shaped honeycomb structures 10b having a smaller pressure loss than the square pillar-shaped honeycomb structures 10a. From the viewpoint of reducing the difference in the flow rate of the process gas between the square pillar-shaped honeycomb structures 10 in the central region C and the square pillar-shaped honeycomb structures 10 in the peripheral region, it is preferable that all of the multiple square pillar-shaped honeycomb structures 10 located in the peripheral region have a smaller pressure loss than the square pillar-shaped honeycomb structures 10 in the central region C.

[0043] In a cross section perpendicular to the extension direction of the cells 14, it is preferable to have one or more square pillar-shaped honeycomb structures 10 in the peripheral region, in which the pressure loss of the square pillar-shaped honeycomb structure 10 at a position where the distance from the center P1 of the reactor to the axial center P2 of the square pillar-shaped honeycomb structure 10 is long is equal to or smaller than the pressure loss of the square pillar-shaped honeycomb structure 10 at a position where the distance is short. With this configuration, it is possible to stably reduce the difference in the flow rate of the process gas between the square pillar-shaped honeycomb structure 10 (10a) in the central region C and the square pillar-shaped honeycomb structure 10 (10b) in the peripheral region. Figures 1 and 2 show an example in which the pressure loss of the square pillar-shaped honeycomb structure 10 (10b) at a position where the distance L1 is long is equal to the pressure loss of the square pillar-shaped honeycomb structure 10 (10b) at a position where the distance L2 is short. Furthermore, when the pressure loss of the square pillar-shaped honeycomb structure 10 at the position where the distance L1 is long is made smaller than the pressure loss of the square pillar-shaped honeycomb structure 10 at the position where the distance L2 is short, for example, a square pillar-shaped honeycomb structure 10 (10c) having a smaller pressure loss than the square pillar-shaped honeycomb structure 10 (10b) may be disposed at the position of the square pillar-shaped honeycomb structure 10 (10b) at the position where the distance L1 is long. An example of a reactor having such a structure is shown in Fig. 5.

[0044] In a cross section perpendicular to the extension direction of the cells 14, the square pillar-shaped honeycomb structure 10 located at or closest to the center P of the reactor is defined as the first group, the square pillar-shaped honeycomb structures 10 arranged around the first group are defined as the second group, and the square pillar-shaped honeycomb structures 10 arranged around the second group or more are defined as the 2+n group (n is 1 or more), in that order. In the second group or more regions, it is preferable to have one or more square pillar-shaped honeycomb structures 10 with a larger group number whose pressure loss is equal to or smaller than that of the square pillar-shaped honeycomb structures 10 with a smaller group number. By adopting such a configuration, it is possible to stably reduce the difference in the flow rate of the treatment gas between the square pillar-shaped honeycomb structures 10 in the central region C (first group) and the square pillar-shaped honeycomb structures 10 in the peripheral region (second group or more).

[0045] FIG. 6 is a schematic diagram illustrating the above-described arrangement of square pillar-shaped honeycomb structures. FIG. 6 shows an example of a reactor having first to third groups of square pillar-shaped honeycomb structures 10. The reactor shown in FIG. 6 includes a square pillar-shaped honeycomb structure 10a as the first group, a square pillar-shaped honeycomb structure 10b as the second group, and a square pillar-shaped honeycomb structure 10c as the third group. The pressure loss of the square pillar-shaped honeycomb structure 10c of the third group is equal to or smaller than the pressure loss of the square pillar-shaped honeycomb structure 10b of the second group. This configuration allows for a stable reduction in the difference in the flow rate of the process gas between the first group of square pillar-shaped honeycomb structures 10a and the second and third groups of square pillar-shaped honeycomb structures 10b, 10c.

[0046] In a reactor having first to second+n groups (n is 1 or more) of square pillar-shaped honeycomb structures 10, it is preferable that the second group or more of the square pillar-shaped honeycomb structures 10 have the same pressure loss. That is, in a cross section perpendicular to the extension direction of the cells 14, the square pillar-shaped honeycomb structures 10 located at or closest to the center P of the reactor are defined as the first group, the square pillar-shaped honeycomb structures 10 arranged around the first group and having the same pressure loss are defined as the second group, and the square pillar-shaped honeycomb structures 10 arranged around the second group or more and having the same pressure loss are defined as the second+n group (n is 1 or more), in the second group or more regions, it is preferable that the pressure loss of one or more square pillar-shaped honeycomb structures 10 having a larger group number is equal to or smaller than the pressure loss of the square pillar-shaped honeycomb structures 10 having a smaller group number. By adopting such a structure, in addition to the effect of stably reducing the difference in the flow rate of the treatment gas between the first group of square pillar-shaped honeycomb structures 10 and the second and third groups of square pillar-shaped honeycomb structures 10, it becomes easier to manufacture the square pillar-shaped honeycomb structures 10 of each group, thereby improving the productivity of the reactor.

[0047] The outer dimensions of the square pillar-shaped honeycomb structures 10 constituting the reactor are not particularly limited and may be the same or different. For example, square pillar-shaped honeycomb structures 10 having various outer dimensions may be combined as shown in Figures 7A and 7B. However, it is preferable that the outer dimensions of all the square pillar-shaped honeycomb structures 10 in the reactor are the same. By making the outer dimensions of all the square pillar-shaped honeycomb structures 10 the same, it becomes easier to manufacture the square pillar-shaped honeycomb structures 10, thereby improving the productivity of the reactor.

[0048] In a cross section perpendicular to the extension direction of the cells 14, it is preferable that the pressure loss of the square pillar-shaped honeycomb structures 10 located at the corners of the plurality of square pillar-shaped honeycomb structures 10 located at the outermost periphery of the reactor is smaller than the pressure loss of the square pillar-shaped honeycomb structures 10 located at the other parts than the corners. Since it is particularly difficult for the process gas to flow through the square pillar-shaped honeycomb structures 10 located at the corners of the plurality of square pillar-shaped honeycomb structures 10 located at the outermost periphery of the reactor, the above configuration can reduce the difference in the flow rate of the process gas flowing through the plurality of square pillar-shaped honeycomb structures 10 located at the outermost periphery of the reactor.

[0049] Here, a schematic diagram for explaining the square pillar-shaped honeycomb structures having the above-mentioned arrangement is shown in Fig. 8. In the reactor shown in Fig. 8, among the plurality of square pillar-shaped honeycomb structures 10 located at the outermost periphery of the reactor, the pressure loss of the square pillar-shaped honeycomb structures 10 (10d) located at the corners is smaller than the pressure loss of the square pillar-shaped honeycomb structures 10 (10c) located other than the corners. By adopting such a configuration, it is possible to reduce the difference in the flow rate of the process gas flowing through the square pillar-shaped honeycomb structures 10c and 10d.

[0050] The method for controlling the pressure loss of the square pillar-shaped honeycomb structure 10 is not particularly limited, and can be controlled by various methods. In one embodiment, the pressure loss of the square pillar-shaped honeycomb structure 10 can be controlled by the cell density of the square pillar-shaped honeycomb structure 10 and / or the thickness of the partition walls 15. For example, the pressure loss can be reduced by increasing the cell density. Also, the pressure loss can be reduced by reducing the thickness of the partition walls 15.

[0051] The ratio of the cell density of the square pillar-shaped honeycomb structure 10 in the central region C to the cell density of the square pillar-shaped honeycomb structure 10 in the peripheral region is preferably more than 1.00 and less than 6.00, more preferably 1.10 to 5.80, and even more preferably 1.20 to 5.60. By controlling the cell density ratio within the above range, the process gas can easily and stably flow through the cells 14 of the square pillar-shaped honeycomb structure 10 in the peripheral region. Here, in this specification, the cell density is a value obtained by dividing the number of cells by the area of ​​one end face (inflow end face 12 or outflow end face 13) of the square pillar-shaped honeycomb structure 10 (the total area of ​​the partition walls 15 and the cells 14 excluding the peripheral wall 11).

[0052] The ratio of the thickness of the partition walls 15 of the quadrangular pillar-shaped honeycomb structure 10 in the central region C to the thickness of the partition walls 15 of the quadrangular pillar-shaped honeycomb structure 10 in the peripheral region is preferably more than 1.00 and less than 6.00, more preferably 1.10 to 5.80, and even more preferably 1.20 to 5.60. By controlling the thickness ratio of the partition walls 15 within the above range, the process gas can be easily and stably circulated through the cells 14 of the quadrangular pillar-shaped honeycomb structure 10 in the peripheral region. Furthermore, by controlling the thickness of the partition walls 15 within the above range, the process gas can be easily and stably circulated through the cells 14 of the quadrangular pillar-shaped honeycomb structure 10 in the peripheral region even when the ratio of the cell density of the quadrangular pillar-shaped honeycomb structure 10 in the central region C to the cell density of the quadrangular pillar-shaped honeycomb structure 10 in the peripheral region is 0.16 to 1.00.

[0053] In another embodiment, the pressure loss of the square pillar-shaped honeycomb structure 10 can be controlled by the porosity of the plugging portions. Specifically, at least a portion of the square pillar-shaped honeycomb structure 10 has plugging portions in the cells 14 on the inflow end face 12 side and / or the outflow end face 13 side, and the porosity of the plugging portions in the square pillar-shaped honeycomb structure 10 in the central region C is configured to be smaller than the porosity of the plugging portions in the square pillar-shaped honeycomb structure 10 in the peripheral region. By controlling the porosity of the plugging portions in this manner, the process gas can easily flow through the cells 14 of the square pillar-shaped honeycomb structure 10 in the peripheral region. The porosity of the plugging portions can be controlled by adjusting the components of the material forming the plugging portions.

[0054] The ratio of the porosity of the plugging portions in the square pillar-shaped honeycomb structure 10 in the central region C to the porosity of the plugging portions in the square pillar-shaped honeycomb structure 10 in the peripheral region is preferably 0.11 or more and less than 1.00, more preferably 0.13 to 0.98, and even more preferably 0.15 to 0.95. By controlling the porosity ratio of the plugging portions within the above range, it becomes easier for the process gas to stably flow through the cells 14 of the square pillar-shaped honeycomb structure 10 in the peripheral region. In this specification, the "porosity of the plugging portions" means the porosity of the plugging portions measured by mercury porosimetry in accordance with JIS R1655:2003.

[0055] In another embodiment, the pressure loss of the square pillar-shaped honeycomb structure 10 can be controlled by the proportion of cells 14 having plugging portions. Specifically, at least a part of the square pillar-shaped honeycomb structure 10 has plugging portions in the cells 14 on the inflow end face 12 side and / or the outflow end face 13 side, and the proportion of cells 14 having plugging portions in the square pillar-shaped honeycomb structure 10 in the central region C is higher than the proportion of cells 14 having plugging portions in the square pillar-shaped honeycomb structure 10 in the peripheral region. By controlling the proportion of cells 14 having plugging portions in this manner, the process gas can easily flow through the cells 14 of the square pillar-shaped honeycomb structure 10 in the peripheral region.

[0056] The ratio of the proportion of cells 14 having plugged portions in the square pillar-shaped honeycomb structure 10 in the peripheral region to the proportion of cells 14 having plugged portions in the square pillar-shaped honeycomb structure 10 in the central region C is preferably less than 1.00, more preferably 0.98 or less, and even more preferably 0.95 or less. By controlling the ratio of the proportion of cells 14 having plugged portions within the above range, it becomes easier for the process gas to stably flow through the cells 14 of the square pillar-shaped honeycomb structure 10 in the peripheral region.

[0057] Next, the quadrangular pillar-shaped honeycomb structure 10 constituting the reactor will be described in detail.

[0058] In a preferred embodiment, one square pillar-shaped honeycomb structure 10 has a side length of 10 to 50 mm (preferably 20 to 40 mm) at the inlet end face 12 and the outlet end face 13, and a length of 10 to 200 mm (preferably 30 to 150 mm) in the extension direction of the cells 14. With a square pillar-shaped honeycomb structure 10 of such a size, a sufficient amount of functional material can be supported in the cells 14, and therefore practicality as a reactor can be ensured.

[0059] The shape of the cells 14 is not particularly limited, but may be polygonal, such as triangular, square, hexagonal, or octagonal, or round, such as circular, elliptical, oval, egg-shaped, or oval, in a cross section perpendicular to the extension direction of the cells 14 of the quadrangular pillar honeycomb structure 10. Each cell may have a single shape or a combination of two or more shapes. Among these cell shapes, a square or hexagonal shape is preferable. By providing cells with such shapes, pressure loss during the flow of the process gas can be reduced. The shape of each cell in the cross section is the same as the shape of each cell at the end face.

[0060] The material of the quadrangular pillar-shaped honeycomb structure 10 (the outer wall 11 and the partition walls 15) is not particularly limited, but it is preferable that the main component is one or more selected from cordierite, mullite, alumina, silica, silicon carbide, and Si-bonded silicon carbide, from the viewpoint of ensuring the strength of the quadrangular pillar-shaped honeycomb structure 10. Here, in this specification, the term "main component" means a component whose proportion in the total components exceeds 50 mass%.

[0061] The thickness of the partition walls 15 is not particularly limited, but is preferably 0.05 mm to 5 mm, more preferably 0.10 mm to 4.5 mm, and even more preferably 0.15 mm to 4 mm, from the viewpoints of ensuring the strength of the quadrangular pillar-shaped honeycomb structure 10 and reducing pressure loss when the process gas passes through the cells 14. In this specification, the "thickness of the partition walls 15" refers to the length of a line segment that crosses the partition walls 15 when the line segment connects the centers of gravity of adjacent cells 14 in a cross section of the quadrangular pillar-shaped honeycomb structure 10 that is perpendicular to the extension direction of the cells 14. The thickness of the partition walls 15 refers to the average value of the thicknesses of all the partition walls 15.

[0062] The porosity of the partition walls 15 is not particularly limited, but is preferably 30% or more and less than 80%, more preferably 35% to 75%, and even more preferably 40% to 70%, from the viewpoints of ensuring the strength of the quadrangular pillar-shaped honeycomb structure 10 and reducing the pressure loss when the process gas passes through the cells 14. In this specification, the "porosity of the partition walls 15" means the porosity of the partition walls 15 measured by mercury porosimetry in accordance with JIS R1655:2003.

[0063] The average pore diameter of the partition walls 15 is not particularly limited, but is preferably 10 μm to 300 μm, more preferably 15 μm to 280 μm, and even more preferably 20 μm to 260 μm, from the viewpoints of ensuring the strength of the square pillar-shaped honeycomb structure 10 and reducing the pressure loss when the process gas passes through the cells 14. In this specification, the "average pore diameter of the partition walls 15" means the pore diameter of the partition walls 15 at an integrated value of 50% in the pore distribution determined by mercury intrusion porosimetry in accordance with JIS R1655:2003.

[0064] The thickness of the peripheral wall 11 is not particularly limited, but is preferably 0.05 mm to 10 mm, more preferably 0.20 mm to 8 mm, and even more preferably 0.30 mm to 6 mm, from the viewpoint of ensuring the strength of the quadrangular pillar-shaped honeycomb structure 10. In this specification, the thickness of the peripheral wall 11 refers to the length in the normal direction to the peripheral surface of the quadrangular pillar-shaped honeycomb structure 10 from the boundary between the peripheral wall 11 and the outermost cell 14 or partition wall 15 to the peripheral surface of the quadrangular pillar-shaped honeycomb structure 10 in a cross section perpendicular to the extension direction of the cells 14 of the quadrangular pillar-shaped honeycomb structure 10.

[0065] The cell density of the square pillar-shaped honeycomb structure 10 is not particularly limited, but from the viewpoint of ensuring the strength of the square pillar-shaped honeycomb structure 10 and increasing the amount of functional material carried, it is preferred that the cell density be 0.05 cells / cm. 2 ~25 cells / cm 2 Preferably, the density is 0.1 cells / cm 2 ~20 cells / cm 2 More preferably, 0.5 cells / cm 2 ~15 cells / cm 2 In this specification, the term "cell density" refers to a value obtained by dividing the number of cells by the area of ​​one end face of the square pillar-shaped honeycomb structure 10 (the total area of ​​the partition walls 15 and the cells 14 excluding the outer peripheral wall 11).

[0066] The reactor may further include a functional material supported on the partition walls 15 of the square pillar-shaped honeycomb structure 10. The functional material may also be supported on the outer peripheral wall 11 facing the cells 14. By supporting the functional material, it becomes possible to recover (adsorb) and release (desorb) the target gas to be captured from the treatment gas.

[0067] FIG. 9A shows a schematic diagram of a cross section perpendicular to the extension direction of the cells 14 of one square pillar-shaped honeycomb structure 10 carrying a functional material. FIG. 9B shows a schematic diagram of a cross section of the square pillar-shaped honeycomb structure 10 of FIG. 9A taken along line b-b'. In the square pillar-shaped honeycomb structure 10 shown in FIGS. 9A and 9B, the functional material 30 is carried on the partition walls 15 and the peripheral wall 11 facing the cells 14. The method for carrying the functional material 30 is not particularly limited, but a layer containing the functional material 30 may be formed on the partition walls 15 and the peripheral wall 11 facing the cells 14 of the square pillar-shaped honeycomb structure 10. The functional material 30 is not particularly limited as long as it can recover the target gas contained in the process gas. For example, an adsorbent for the target gas can be used. By using an adsorbent as the functional material 30, the target gas can be adsorbed and recovered, and the recovered target gas can be easily desorbed by changing conditions such as temperature.

[0068] The adsorbent may be selected appropriately depending on the type of gas to be captured, and is not particularly limited. Examples of adsorbents effective for adsorbing target gases such as carbon dioxide (CO2) include amine compounds, organometallic complexes, and nanoporous ceramics or mesoporous silica supported with amine compounds and / or organometallic complexes. These may be used alone or in combination of two or more. Examples of amine compounds include, but are not limited to, monoethanolamine (MEA) and N-methyldiethanolamine (MDEA). Examples of organometallic complexes include, but are not limited to, porous metal-organic frameworks (MOFs) having a structure capable of adsorbing target gases in their pores. Among the various adsorbents listed above, amine compounds and / or metal-organic frameworks are preferred. By using these adsorbents, the amount of adsorption of target gases such as carbon dioxide (CO2) can be stably improved.

[0069] The thickness of the layer containing the functional material 30 is not particularly limited and may be determined depending on the size of the cell 14. For example, from the viewpoint of ensuring sufficient contact with air, the thickness of the layer containing the functional material 30 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of preventing the layer containing the functional material 30 from peeling off from the partition wall 15 or the outer peripheral wall 11, the thickness of the layer containing the functional material 30 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less.

[0070] The reactor can use a plurality of square pillar-shaped honeycomb structures 10 as the reactor, but may further include a tubular member that houses the square pillar-shaped honeycomb structures 10. Here, FIG. 10 is a schematic diagram of a cross section perpendicular to the extension direction of the cells 14 of a plurality of square pillar-shaped honeycomb structures 10 housed in the tubular member. As shown in FIG. 10, this reactor includes a plurality of square pillar-shaped honeycomb structures 10 and a tubular member 40 that houses the plurality of square pillar-shaped honeycomb structures 10. By housing the plurality of square pillar-shaped honeycomb structures 10 in the tubular member 40, the plurality of square pillar-shaped honeycomb structures 10 can be protected from external impacts and the like.

[0071] In Fig. 10, the square pillar-shaped honeycomb structure 10 and the tubular member 40 are in direct contact with each other, but another member such as an insulating material may be disposed between the square pillar-shaped honeycomb structure 10 and the tubular member 40. The tubular member 40 is not particularly limited, but is preferably made of a metal from the viewpoint of manufacturability. Examples of materials that can be used for the tubular member 40 include stainless steel, titanium alloy, copper alloy, aluminum alloy, and brass. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

[0072] <Method for manufacturing reactor> The method for manufacturing a reactor according to the embodiment of the present invention is not particularly limited as long as it is a method that can form the above-mentioned structure. For example, the method for manufacturing a reactor according to the embodiment of the present invention includes a step (step A) of manufacturing a quadrangular pillar-shaped honeycomb structure 10 and a step (step B) of arranging the quadrangular pillar-shaped honeycomb structure 10 at a predetermined position.

[0073] In step A, the method for manufacturing the square pillar-shaped honeycomb structure 10 is not particularly limited and can be carried out according to methods known in the art. For example, the square pillar-shaped honeycomb structure 10 can be manufactured as follows. First, a clay containing ceramic powder is extruded into a desired shape to produce a square pillar-shaped honeycomb formed body. By selecting an appropriate die and jig, the shape and density of each cell, the shape and thickness of the partition walls 15 and the outer peripheral wall 11, etc. can be controlled. The ceramic powder can be the aforementioned ceramic powder or a raw material powder (e.g., a cordierite raw material) that will become the aforementioned ceramic after firing. The cordierite raw material is a raw material that will become cordierite upon firing. The cordierite raw material preferably has a chemical composition of 30 to 45 mass% alumina (Al2O3) (including aluminum hydroxide converted to alumina), 11 to 17 mass% magnesia (MgO), and 42 to 57 mass% silica (SiO2). The clay may contain a binder, a pore-forming agent, a dispersant, water, an organic solvent, etc. The porosity and average pore diameter of the partition walls 15 can be controlled by appropriately selecting the type and amount of the ceramic powder, binder, pore-forming agent, and dispersant used. Next, the square pillar-shaped honeycomb molded body obtained above is dried and fired to obtain the square pillar-shaped honeycomb structure 10. The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying can be used. Among these, a drying method combining hot air drying with microwave drying or dielectric drying is preferred because it can quickly and uniformly dry the entire square pillar-shaped honeycomb molded body.

[0074] Next, in step B, the quadrangular pillar-shaped honeycomb structure 10 obtained above is arranged at a predetermined position. Specifically, a plurality of quadrangular pillar-shaped honeycomb structures 10 are prepared and arranged so that the outer peripheral walls 11 of the plurality of quadrangular pillar-shaped honeycomb structures 10, which are parallel to the extension direction of the cells 14, are in direct or indirect contact with each other.

[0075] In addition to the above steps, the manufacturing method of a reactor according to an embodiment of the present invention can further include a step of supporting a functional material 30 on the partition walls 15 of the square pillar-shaped honeycomb structure 10. This step may be performed at any stage after step A. For example, this step may be performed between steps A and B, or after step B. The method for supporting the functional material 30 is not particularly limited, but it can be formed, for example, by the following steps. The square pillar-shaped honeycomb structure 10 is immersed in a slurry containing the functional material 30, an organic binder, and a dispersion medium for a predetermined period of time, and excess slurry from the end faces and outer periphery of the square pillar-shaped honeycomb structure 10 is removed by blowing and wiping. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. The slurry is then dried to support the functional material 30 on the surfaces of the partition walls 15 and the like. The drying can be performed by heating the square pillar-shaped honeycomb structure 10 to a temperature of, for example, about 120 to 600°C. The series of steps of immersion, slurry removal, and drying may be performed only once, but can be repeated multiple times to support a desired amount of functional material 30.

[0076] In addition to the above steps, the manufacturing method of the reactor according to the embodiment of the present invention can further include a step of accommodating a plurality of quadrangular pillar-shaped honeycomb structures 10 in the tubular member 40. The method of accommodating a plurality of quadrangular pillar-shaped honeycomb structures 10 in the tubular member 40 is not particularly limited, and any known method can be used. For example, the method can include a fixing method using a fit such as clearance fit, interference fit, or shrink fit, as well as brazing, welding, diffusion bonding, or the like.

[0077] <Gas Recovery Apparatus> A gas recovery apparatus according to an embodiment of the present invention can be suitably used to recover and release a target gas contained in a process gas. FIG. 11 is a schematic diagram showing the configuration of a gas recovery apparatus according to an embodiment of the present invention. As shown in FIG. 11, the gas recovery apparatus 100 includes a reactor 110, a heating unit 120 capable of heating the reactor, a gas supply pipe 130 capable of supplying a target gas or purge gas to an inlet 111 of the reactor 110, and a gas exhaust pipe 140 capable of exhausting the target gas or purge gas from an outlet 112 of the reactor 110. The reactor 110 uses the above-described reactor, which allows the target gas containing the target gas to easily flow into the cells 14 in the outer circumferential region, thereby increasing the recovery amount of the target gas and extending its lifespan. Therefore, the gas recovery apparatus 100 can maintain good gas recovery performance over a long period of time. Furthermore, when the above-mentioned reactor is loaded with functional material 30, the amount of heat required when releasing (desorbing) the target gas to be captured can be reduced, thereby reducing the operating costs of the gas recovery device 100.

[0078] The gas supply pipe 130 has a gas supply branch pipe branched into two. This gas supply branch pipe can be a first gas supply branch pipe 131 capable of supplying a processing gas, and a second gas supply branch pipe 132 capable of supplying a purge gas. The gas exhaust pipe 140 has a gas exhaust branch pipe branched into two. This gas exhaust branch pipe can be a first gas exhaust branch pipe 141 capable of exhausting a processing gas, and a second gas exhaust branch pipe 142 capable of exhausting a purge gas. The gas recovery apparatus 100 can further include a supply gas switching valve 150 capable of blocking the first gas supply branch pipe 131 or the second gas supply branch pipe 132, and an exhaust gas switching valve 160 capable of blocking the first gas exhaust branch pipe 141 or the second gas exhaust branch pipe 142.

[0079] In the gas recovery device 100 having the above-described structure, when recovering the target gas contained in the treatment gas, the supply gas switching valve 150 is switched to block the second gas supply branch pipe 132 and open the first gas supply branch pipe 131, and the exhaust gas switching valve 160 is switched to block the second gas exhaust branch pipe 142 and open the first gas exhaust branch pipe 141. Next, the treatment gas containing the target gas to be captured is supplied from the first gas supply branch pipe 131 through the gas supply pipe 130 to the inlet 111 of the reactor 110. The target gas to be captured is recovered from the treatment gas supplied to the reactor 110 and discharged from the outlet 112. The discharged treatment gas is discharged from the first gas exhaust branch pipe 141 via the gas exhaust pipe 140.

[0080] Next, when the target gas to be captured recovered in the reactor 110 is to be desorbed, the supply gas switching valve 150 is switched to open the second gas supply branch pipe 132 and block the first gas supply branch pipe 131, and the exhaust gas switching valve 160 is switched to open the second gas exhaust branch pipe 142 and block the first gas exhaust branch pipe 141. Next, purge gas is supplied from the second gas supply branch pipe 132 through the gas supply pipe 130 to the inlet 111 of the reactor 110. At this time, the reactor 110 is heated by the heating unit 120. The purge gas supplied to the reactor 110 is discharged from the outlet 112 together with the target gas to be captured in the functional material 30 of the reactor 110. The purge gas containing the target gas to be captured is discharged from the second gas exhaust branch pipe 142 via the gas exhaust pipe 140. Here, in this specification, the term "purge gas" refers to a gas that can desorb the target gas captured in the functional material 30 of the reactor 110 and be discharged from the reactor 110. The purge gas may be selected appropriately depending on the type of target gas. For example, when the target gas is carbon dioxide, water vapor or the like can be used. The water vapor is preferably heated to 100°C or higher (e.g., 120°C) in the reactor 110 by heating with the heating unit 120.

[0081] 10, 10a, 10b, 10c, 10d Square pillar-shaped honeycomb structure 11 Outer wall 12 Inlet end face 13 Outlet end face 14 Cell 15 Partition wall 30 Functional material 40 Cylindrical member 100 Gas recovery device 110 Reactor 111 Inlet 112 Outlet 120 Heating section 130 Gas supply pipe 131 First gas supply branch pipe 132 Second gas supply branch pipe 140 Gas exhaust pipe 141 First gas exhaust branch pipe 142 Second gas exhaust branch pipe 150 Supply gas switching valve 160 Exhaust gas switching valve

Claims

1. A reactor comprising a plurality of quadrangular prism honeycomb structures each having an outer peripheral wall and a partition wall disposed inside the outer peripheral wall and partitioning a plurality of cells extending from an inflow end face to an outflow end face through which a processing gas containing a gas to be captured can flow, and the outer peripheral walls of the plurality of quadrangular prism honeycomb structures being arranged so as to be in direct or indirect contact with each other in a direction parallel to the direction in which the cells extend, wherein in a cross section orthogonal to the direction in which the cells extend, one or more quadrangular prism honeycomb structures having a pressure loss smaller than that of the quadrangular prism honeycomb structures in the central region are provided in an outer peripheral region around one or more of the quadrangular prism honeycomb structures located in the central region when the processing gas is caused to flow through the quadrangular prism honeycomb structures.

2. The reactor according to claim 1, wherein in a cross section orthogonal to the direction in which the cells extend, when the distance from the center of the reactor to the axial center of the quadrangular prism honeycomb structure is measured, one or more quadrangular prism honeycomb structures having a pressure loss equal to or smaller than that of the quadrangular prism honeycomb structure at a position where the distance is long are provided in the outer peripheral region.

3. The reactor according to claim 1, wherein in a cross section orthogonal to the direction in which the cells extend, when the quadrangular prism honeycomb structure located at the center of the reactor or closest to the center of the reactor is defined as the first group, the quadrangular prism honeycomb structures arranged around the first group are defined as the second group, and the quadrangular prism honeycomb structures arranged around the second group or higher are defined as the second + n group (n is 1 or more) in order, in the region of the second group or higher, one or more quadrangular prism honeycomb structures having a pressure loss equal to or smaller than that of the quadrangular prism honeycomb structure with a smaller group number are provided.

4. In a cross-section orthogonal to the direction in which the cell extends, when the square columnar honeycomb structure located at the center of the reactor or closest to the center of the reactor is defined as the first group, the square columnar honeycomb structures having the same pressure loss arranged around the first group are defined as the second group, and the square columnar honeycomb structures having the same pressure loss arranged around the second group or more are defined as the second + n group (n is 1 or more) in order, in the region of the second group or more, the reactor according to claim 1, having one or more square columnar honeycomb structures in which the pressure loss of the square columnar honeycomb structure with a larger group number is equal to or smaller than the pressure loss of the square columnar honeycomb structure with a smaller group number.

5. The reactor according to any one of claims 1 to 4, wherein the outer dimensions of all the square columnar honeycomb structures in the reactor are the same.

6. In a cross-section orthogonal to the direction in which the cell extends, among the plurality of square columnar honeycomb structures located at the outermost periphery of the reactor, the reactor according to claim 5, wherein the pressure loss of the square columnar honeycomb structure located at the corner is smaller than the pressure loss of the square columnar honeycomb structure located outside the corner.

7. The reactor according to any one of claims 1 to 4, wherein the pressure loss of the square columnar honeycomb structure is controlled by the cell density of the square columnar honeycomb structure and / or the thickness of the partition wall.

8. The reactor according to claim 7, wherein the ratio of the cell density of the square columnar honeycomb structure in the central region to the cell density of the square columnar honeycomb structure in the outer peripheral region is more than 1.00 and less than 6.

00.

9. The reactor according to claim 7, wherein the ratio of the cell density of the square columnar honeycomb structure in the central region to the cell density of the square columnar honeycomb structure in the outer peripheral region is 0.16 to 1.00, and the ratio of the thickness of the partition wall of the square columnar honeycomb structure in the central region to the thickness of the partition wall of the square columnar honeycomb structure in the outer peripheral region is more than 1.00 and less than 6.

00.

10. At least a part of the square columnar honeycomb structure has a plugging portion in the cells on the inflow end face side and / or the outflow end face side, and the porosity of the plugging portion in the square columnar honeycomb structure in the central region is smaller than the porosity of the plugging portion in the square columnar honeycomb structure in the outer peripheral region. The reactor according to any one of claims 1 to 4.

11. The ratio of the porosity of the plugging portion in the square columnar honeycomb structure in the central region to the porosity of the plugging portion in the square columnar honeycomb structure in the outer peripheral region is 0.11 or more and less than 1.

00. The reactor according to claim 10.

12. At least a part of the square columnar honeycomb structure has a plugging portion in the cells on the inflow end face side and / or the outflow end face side, and the ratio of the cells having the plugging portion in the square columnar honeycomb structure in the central region is higher than the ratio of the cells having the plugging portion in the square columnar honeycomb structure in the outer peripheral region. The reactor according to any one of claims 1 to 4.

13. The ratio of the ratio of the cells having the plugging portion in the square columnar honeycomb structure in the central region to the ratio of the cells having the plugging portion in the square columnar honeycomb structure in the outer peripheral region is less than 1.

00. The reactor according to claim 12.

14. In a cross section orthogonal to the direction in which the cells extend, the shape of the cells is a quadrilateral or a hexagon. The reactor according to any one of claims 1 to 4.

15. The length of the cells of the square columnar honeycomb structure in the extending direction is 10 to 200 mm. The reactor according to any one of claims 1 to 4.

16. The square columnar honeycomb structure contains, as a main component, one or more selected from cordierite, mullite, alumina, silica, silicon carbide, and Si-bonded silicon carbide. The reactor according to any one of claims 1 to 4.

17. The porosity of the partition wall is 30% or more and less than 80%. The reactor according to any one of claims 1 to 4.

18. The average pore diameter of the partition wall is 10 to 300 μm. The reactor according to any one of claims 1 to 4.

19. The reactor according to any one of claims 1 to 4 further comprises a functional material supported on the partition wall.

20. The functional material is an amine compound and / or a metal organic framework. The reactor according to claim 19.

21. The reactor according to any one of claims 1 to 4, further comprising a cylindrical member for housing the square columnar honeycomb structure.

22. A gas recovery device for adsorbing and releasing a gas to be captured contained in a processing gas, comprising: the reactor according to any one of claims 1 to 4; a heating unit capable of heating the reactor; a gas supply pipe capable of supplying the processing gas or a purge gas to an inlet of the reactor; and a gas discharge pipe capable of discharging the processing gas or the purge gas from an outlet of the reactor.

23. The gas supply pipe has a gas supply branch pipe branched into two, and the gas supply branch pipe is a first gas supply branch pipe capable of supplying the processing gas and a second gas supply branch pipe capable of supplying the purge gas. The gas discharge pipe has a gas discharge branch pipe branched into two, and the gas discharge branch pipe is a first gas discharge branch pipe capable of discharging the processing gas and a second gas discharge branch pipe capable of discharging the purge gas. The gas recovery device further comprises a supply gas switching valve capable of shutting off the first gas supply branch pipe or the second gas supply branch pipe, and a discharge gas switching valve capable of shutting off the first gas discharge branch pipe or the second gas discharge branch pipe.

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