Carbon dioxide capture device and carbon dioxide capture method

Abstract

To provide a carbon dioxide recovery device which allows its whole device to be made compact while securing recovery efficiency of carbon dioxide.SOLUTION: A carbon dioxide recovery device 1 includes a sealing container 3 having a gas supply space 11 to which gas to be treated containing carbon dioxide is supplied and that can be compressed, a carbon dioxide permselective membrane 4 which is arranged in the sealing container 3 and selectively permeates the carbon dioxide from the gas to be treated supplied to the gas supply space 11, and compression means 5 for compressing the gas supply space 11 of the sealing container 3, and pressure-feeding the gas to be treated supplied to the gas supply space 11 to the carbon dioxide permselective membrane 4. Thereby, it allows its whole device to be made compact while securing recovery efficiency of carbon dioxide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a carbon dioxide recovery apparatus and a carbon dioxide recovery method for separating and recovering carbon dioxide from a gas to be treated.

Background Art

[0002] In marine civil engineering, there is a deep mixing method (hereinafter referred to as the CDM method) in which cement-improved piles are constructed in soft seabed ground for reinforcement. When adopting the CDM method at sea, a special workboat called a CDM ship is used to pump cement milk, which is a mixture of cement, water, and admixtures, into the ground. Therefore, the amount of carbon dioxide emissions per day of a CDM ship is at the level of several tons. Based on this current situation, as a reform of awareness towards environmental problems in recent years, reducing carbon dioxide emissions towards carbon neutrality has become an essential issue.

[0003] That is, there are few methods for recovering carbon dioxide from exhaust gas emitted from workboats used in marine construction, such as the above-mentioned CDM ships, dredgers, crane ships, SCP ships (sand compaction ships), etc., and connecting it to reuse. In aiming for carbon neutrality, reducing carbon dioxide emissions from these workboats is an urgent issue.

[0004] Therefore, as carbon dioxide recovery technologies, there are chemical absorption methods, physical absorption methods, physical adsorption methods, membrane separation methods, cryogenic separation methods, oxygen combustion methods, etc. However, in the case of physical adsorption methods, etc., the entire apparatus becomes large-sized and cannot be installed on workboats such as the above-mentioned CDM ships, making it difficult to adopt.

[0005] Furthermore, as a prior art for carbon dioxide recovery devices, Patent Document 1 discloses a carbon dioxide separation and recovery device comprising: a carbon dioxide separator configured to selectively permeate carbon dioxide contained in carbon dioxide-containing gas flowing into a first space to a second space using a separation membrane; a water storage section for storing water in a substantially sealed space communicating with the second space; a pump for reducing the pressure in the second space; and a water separator for separating water from the gas discharged from the outlet of the pump. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-159813 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the carbon dioxide separation and recovery device described in Patent Document 1 has a complex structure and is disadvantageous from the standpoint of cost and other factors. Moreover, in addition to the carbon dioxide separator, it requires a water storage section, a pump, and a water separator, and the entire device becomes large, making it difficult to install on a work vessel such as the CDM ship mentioned above, and therefore it cannot be adopted.

[0008] The present invention has been made in view of the above problems, and aims to provide a carbon dioxide recovery device and a carbon dioxide recovery method that can be configured compactly while ensuring the efficiency of carbon dioxide recovery. [Means for solving the problem]

[0009] As a means to solve the above problems, the invention relating to the carbon dioxide recovery apparatus of claim 1 comprises: a sealed container having a compressible gas supply space into which a gas to be treated containing carbon dioxide is supplied; a carbon dioxide selective permeable membrane disposed inside the sealed container and selectively permeating carbon dioxide from the gas to be treated supplied to the gas supply space; and a compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane. The gas to be treated is exhaust gas discharged from a work vessel used for offshore construction. It is characterized by the following: In the invention of claim 1, when a gas to be treated containing carbon dioxide is supplied to the gas supply space in a sealed container, the gas supply space of the sealed container can be compressed by the compression means, thereby quickly pressurizing the gas to be treated in the gas supply space to the carbon dioxide selective permeable membrane. As a result, the carbon dioxide in the gas to be treated permeates through the carbon dioxide selective permeable membrane, allowing the carbon dioxide to be separated from the gas to be treated and recovered.

[0010] Also, Claim 1 Invention relating to a carbon dioxide capture device So, The gas to be treated is exhaust gas discharged from a work vessel used for offshore construction. Therefore, The carbon dioxide capture device is to be placed on a work vessel used for offshore construction. Can do it, The carbon dioxide recovery device is particularly effective in separating and recovering carbon dioxide from the exhaust gas emitted from the work vessel.

[0011] Claim 2 The invention relating to the carbon dioxide capture device is The system comprises a sealed container into which a gas to be treated containing carbon dioxide is supplied and which has a compressible gas supply space; a carbon dioxide selective permeable membrane disposed within the sealed container and selectively permeating carbon dioxide from the gas to be treated supplied to the gas supply space; and a compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane. The carbon dioxide selective permeable membrane is provided in a pair facing each other, and the carbon dioxide that flows into the carbon dioxide inflow space between the pair of carbon dioxide selective permeable membranes is recovered from the sealed container to the outside. Claim 2 This invention makes it possible to increase the amount of carbon dioxide recovered per unit time.

[0012] Claim 3 The invention relating to the carbon dioxide capture device is The system comprises a sealed container into which a gas to be treated containing carbon dioxide is supplied and which has a compressible gas supply space; a carbon dioxide selective permeable membrane disposed within the sealed container and selectively permeating carbon dioxide from the gas to be treated supplied to the gas supply space; and a compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane. The invention is characterized in that, within the sealed container, a carbon dioxide concentration meter is positioned in the separated carbon dioxide inflow space located downstream of the carbon dioxide selective permeable membrane in the flow direction of the gas to be treated. Claim 3 In this invention, by managing the detection results from a carbon dioxide concentration meter over time, it is possible to identify problems such as damage or clogging of the carbon dioxide selective permeable membrane and determine when maintenance is needed.

[0013] Claim 4 The invention relating to the carbon dioxide capture device is The system comprises a sealed container into which a gas to be treated containing carbon dioxide is supplied and which has a compressible gas supply space; a carbon dioxide selective permeable membrane disposed within the sealed container and selectively permeating carbon dioxide from the gas to be treated supplied to the gas supply space; and a compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane. Inside the sealed container, a pair of opposing containers are positioned approximately in the center in the compression direction. The aforementioned The invention is characterized by comprising a carbon dioxide inflow space provided between carbon dioxide selective permeable membranes, and gas supply spaces arranged so as to sandwich the carbon dioxide inflow space in the compression direction. Claim 4 In this invention, when a sealed container is compressed, the two gas supply spaces inside are compressed, and the gas to be treated in each gas supply space is pumped to a pair of carbon dioxide selective permeable membranes, where carbon dioxide is separated and filled into the carbon dioxide inlet space. As a result, the amount of carbon dioxide recovered per unit time is increased.

[0014] Claim 5 The invention relating to the carbon dioxide capture device is, Any one of items 1-4 In the invention described above, the compression means is configured as a press machine having an expandable and contractible pressing shaft, and the gas supply space is compressed by the pressing shaft of the press machine. Claim 5 In this invention, the compression means has a simple configuration, allowing the entire device to be made compact.

[0015] Claim 6 The invention relating to a carbon dioxide capture method is a carbon dioxide capture method that utilizes a carbon dioxide selective permeable membrane that selectively permeates carbon dioxide, and includes carbon dioxide Exhaust gases emitted from workboats used for offshore construction.A first pumping step of pumping the above-mentioned through a gas supply space in a sealed container to the carbon dioxide selective permeable membrane, and the above-mentioned exhaust gas A second pumping step of compressing the supplied gas supply space and pumping the The exhaust gas in the gas supply space to the carbon dioxide selective permeable membrane, characterized by including. In the invention of claim 6 , as the first pumping step, <s Exhaust gases emitted from workboats used in offshore construction. When is pumped into the gas supply space at a pressure higher than atmospheric pressure (for example, 2 atmospheres), the exhaust gas of the gas supply space is 2 atmospheres. If the carbon dioxide inflow space located on the downstream side from the carbon dioxide selective permeable membrane is 1 atmosphere, then due to the pressure difference, exhaust gas is easily pumped to the carbon dioxide selective permeable membrane. Next, as the second pumping step, by compressing the gas supply space and increasing the pressure in the gas supply space, the exhaust gas in the gas supply space can be quickly pumped to the carbon dioxide selective permeable membrane. By these two-stage first and second pumping steps, exhaust gas can be efficiently pumped to the carbon dioxide selective permeable membrane, and the recovery efficiency of carbon dioxide can be improved.

Effect of the Invention

[0016] The carbon dioxide recovery device and the carbon dioxide recovery method according to the present invention can configure the entire device in a compact manner while ensuring the recovery efficiency of carbon dioxide.

Brief Explanation of Drawings

[0017] [Figure 1] FIG. 1 is a schematic perspective view of a carbon dioxide recovery device according to an embodiment of the present invention. [Figure 2] FIG. 2(a) is a front view showing an initial state of a sealed container employed in the carbon dioxide recovery device according to an embodiment of the present invention, and (b) is a front view showing a state where a compressive load is applied to the sealed container from the state of (a). [Figure 3] FIG. 3 is a schematic perspective view showing the operation of the carbon dioxide recovery device according to an embodiment of the present invention step by step. [Figure 4]Figure 4 is a schematic perspective view illustrating the operation of the carbon dioxide capture device according to the embodiment of the present invention, following on from Figure 3. [Modes for carrying out the invention]

[0018] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to Figures 1 to 4. The carbon dioxide recovery device 1 according to this embodiment of the present invention is mounted on a CDM vessel (not shown) used in the CDM method. The CDM vessel has an installation area of ​​approximately 10 m (lengthwise) x 10 m (widthwise), and the carbon dioxide recovery device 1 according to this embodiment can be installed within this installation area. In other words, the carbon dioxide recovery device 1 according to this embodiment is configured to be small and compact, with an overall installation area (size on a planar surface) smaller than approximately 10 m (lengthwise) x 10 m (widthwise), preferably to about 8 m (lengthwise) x 4 m (widthwise). The carbon dioxide recovery device 1 according to this embodiment is for recovering carbon dioxide from exhaust gases discharged from a CDM vessel used in the CDM method.

[0019] As shown in Figures 1 and 2, the carbon dioxide recovery apparatus 1 according to this embodiment comprises a sealed container 3 to which a gas to be treated containing carbon dioxide is supplied and which has compressible gas supply spaces 11, 11; carbon dioxide selective permeable membranes 4, 4 disposed inside the sealed container 3 and selectively permeating carbon dioxide from the gas to be treated; a compression means 5 that compresses the gas supply spaces 11, 11 of the sealed container 3 and pumps the gas to be treated supplied to the gas supply spaces 11, 11 to the carbon dioxide selective permeable membranes 4, 4; and a carbon dioxide concentration meter 6 disposed in a carbon dioxide inflow space 10 located downstream of the carbon dioxide selective permeable membrane 4 in the flow direction of the gas to be treated.

[0020] The sealed container 3 is configured as a rectangular parallelepiped with an internal space. The sealed container 3 is configured so that its internal volume is reduced by a compressive load from one direction by the compression means 5. Inside the sealed container 3 is a carbon dioxide inlet space 10 located approximately in the center in the compression direction (width direction) and provided between a pair of opposing carbon dioxide selective permeable membranes 4, 4, and gas supply spaces 11, 11 located on either side of the carbon dioxide inlet space 10 in the compression direction, to which the gas to be treated is supplied.

[0021] The sealed container 3 is configured such that the volume of each gas supply space 11, 11 can be reduced by the compressive load from the compression means 5, while the carbon dioxide inlet space 10 is not compressed and its volume cannot be reduced. In other words, the sealed container 3 is configured such that a pressure difference is created between each gas supply space 11, 11 and the carbon dioxide inlet space 10 by the compressive load from the compression means 5. After residual gas is discharged from the residual gas discharge pipe 16 (described later) and the compressive load from the compression means 5 is released, each gas supply space 11, 11 of the sealed container 3 is restored to its initial shape by the inflow of the gas to be processed from the gas supply pipes 14, 14 (described later) as the next batch.

[0022] As described above, a pair of carbon dioxide selective permeable membranes 4, 4 are arranged in the sealed container 3, facing each other, approximately in the center in the compression direction (width direction). A carbon dioxide inflow space 10 is placed between the pair of carbon dioxide selective permeable membranes 4, 4. A carbon dioxide concentration meter 6 is placed in the carbon dioxide inflow space 10. The carbon dioxide concentration meter 6 allows for accurate measurement of the carbon dioxide concentration in the carbon dioxide inflow space 10. The carbon dioxide selective permeable membrane 4 selectively permeates carbon dioxide from the gas to be treated that is pumped (introduced). Specifically, the carbon dioxide selective permeable membrane 4 is composed of a gel particle membrane of a polymer compound having amino groups (amine-containing gel particle membrane) and a carrier that supports the gel particle membrane. For example, a porous film is used as the carrier.

[0023] For example, the carbon dioxide selective permeable membrane 4 is constructed by immersing a porous film in a water tank filled with gel particles to form an amine-containing gel particle membrane of a predetermined thickness. The amount of gel particles supported on the porous film is made uniform by vibrating the film after it has been removed from the gel particle immersion. The carrier of the carbon dioxide selective permeable membrane 4 is airtightly connected along the inner wall surface of the sealed container 3 to divide the inside of the sealed container 3 into a carbon dioxide inlet space 10 and gas supply spaces 11, 11. A carbon dioxide exhaust pipe 18 communicating with the carbon dioxide inlet space 10 is provided on the upper end surface of the sealed container 3. This carbon dioxide exhaust pipe 18 is connected to a cylinder 20 or the like that stores carbon dioxide, either as a gas or in liquefaction. There may be multiple carbon dioxide exhaust pipes 18, or there may be just one. In this embodiment, there is one carbon dioxide exhaust pipe 18.

[0024] As shown in Figures 1 and 2, a pressing plate 24, configured to move back and forth toward the sealed container 3, is connected to the front surface (outer wall surface on the compression means 5 side) of the sealed container 3 so as to abut against it. The pressing plate 24 is formed to cover the entire front surface of the sealed container 3. The pressing plate 24 is provided with a gas supply pipe 14 that communicates with one of the gas supply spaces 11. This gas supply pipe 14 protrudes toward the compression means 5 side. The pressing plate 24 is also provided with a residual gas discharge pipe 16 that communicates with one of the gas supply spaces 11. This residual gas discharge pipe 16 also protrudes toward the compression means 5 side. These gas supply pipes 14 and residual gas discharge pipes 16 are positioned approximately in the center of the longitudinal direction of the pressing plate 24. On the pressing plate 24, the gas supply pipe 14 is positioned on the upper side and the residual gas discharge pipe 16 is positioned on the lower side.

[0025] As shown in Figure 2, on the back of the sealed container 3 (the outer wall surface opposite to the compression means 5 side), a pressure resistance plate 27 is positioned to ensure that the pressing force from the pressing shaft 25 (pressing plate 24) of the compression means 5 to the sealed container 3 is reliably transmitted to the sealed container 3. The position of the pressure resistance plate 27 does not change. The pressure resistance plate 27 is formed to cover the entire back surface of the sealed container 3. A gas supply pipe 14 is provided on the pressure resistance plate 27, which communicates with the other gas supply space 11. This gas supply pipe 14 protrudes in the direction opposite to the compression means 5 side. In addition, a residual gas discharge pipe 16 is provided on the pressure resistance plate 27, which communicates with the other gas supply space 11. This residual gas discharge pipe 16 also protrudes in the direction opposite to the compression means 5 side. These gas supply pipe 14 and residual gas discharge pipe 16 are positioned approximately in the center of the longitudinal direction of the pressure resistance plate 27. In the pressure resistance plate 27, the gas supply pipe 14 is positioned on the upper side and the residual gas discharge pipe 16 is positioned on the lower side.

[0026] The gas to be treated is then pumped and supplied from these gas supply pipes 14, 14 to each gas supply space 11, 11. Meanwhile, the residual gas remaining in these gas supply spaces 11, 11 after carbon dioxide has been separated from the gas to be treated is discharged to the outside from each residual gas discharge pipe 16, 16. The thickness of the pressure plate 24 and the thickness of the pressure resistance plate 27 are approximately the same. On the other hand, the area of ​​the pressure resistance plate 27 is slightly larger than the area of ​​the pressure plate 24.

[0027] The compression means 5 consists of a general press machine. The compression means 5 consists of a press machine having an extendable and retractable pressing shaft 25. Multiple compression means 5 may be provided, or only one may be provided. In this embodiment, two compression means 5 are provided. The extendable and retractable pressing shaft 25 of each compression means 5 presses and moves the pressing plate 24, thereby compressing each gas supply space 11, 11 of the sealed container 3 and reducing their respective volumes. In this embodiment, a pressing resistance plate 27 is placed, and each compression means 5, 5 presses and moves the pressing plate 24 to compress each gas supply space 11, 11 of the sealed container 3. However, instead of placing a pressing resistance plate 27 on the back of the sealed container 3, a pressing plate 24 may be connected to the back so as to be able to move back and forth toward the sealed container 3, and each compression means 5, 5 presses the front and back of the sealed container 3 via the pressing plates 24, 24 to compress each gas supply space 11, 11 of the sealed container 3.

[0028] Next, the operation of the carbon dioxide recovery device 1 according to this embodiment will be explained based on Figures 3 and 4, with reference to Figure 2 as appropriate. First, referring to Figure 3(a), the gas to be treated, which contains carbon dioxide, is pumped under pressure through the gas supply pipes 14, 14 to each gas supply space 11, 11 of the sealed container 3, thereby pumping the gas to be treated through each gas supply space 11, 11 to the pair of carbon dioxide selective permeable membranes 4, 4 (first pumping step). Then, the carbon dioxide in the gas to be treated permeates through each carbon dioxide selective permeable membrane 4, 4 and flows into and fills the carbon dioxide inflow space 10 between the pair of carbon dioxide selective permeable membranes 4, 4. At this time, each residual gas discharge pipe 16, 16 is kept closed, and the carbon dioxide discharge pipe 18 is opened or closed as needed in consideration of the internal pressure of the carbon dioxide inflow space 10, etc. It is important to keep the internal pressure of the carbon dioxide inflow space 10 low. Subsequently, after a predetermined amount of the gas to be treated has been pumped to each gas supply space 11, 11 of the sealed container 3, each gas supply pipe 14, 14 is closed.

[0029] Next, referring to Figures 2(b) and 3(b), each compression means 5 is driven to extend the pressing shaft 25 of each compression means 5 by the required amount, and the pressing plate 24 is advanced to press against the front of the sealed container 3. As a result, each gas supply space 11, 11 in the sealed container 3 is compressed, reducing its volume, and consequently, high pressure is applied only within each gas supply space 11, 11. In other words, by pressing the front of the sealed container 3 via the pressing plate 24 using each compression means 5, the pressure difference between each gas supply space 11, 11 and the carbon dioxide inlet space 10 increases. Then, due to the pressure difference between each gas supply space 11, 11 and the carbon dioxide inlet space 10, the gas to be processed in each gas supply space 11, 11 is pumped to the pair of carbon dioxide selective permeable membranes 4, 4 (second pumping step). As a result, carbon dioxide in the gas to be treated in each gas supply space 11, 11 permeates through each carbon dioxide selective permeable membrane 4, 4 and flows into and fills the carbon dioxide inflow space 10 between the pair of carbon dioxide selective permeable membranes 4, 4.

[0030] Next, referring to Figure 3(c), the carbon dioxide discharged (or drawn in) from the carbon dioxide inlet space 10 of the sealed container 3 via the carbon dioxide discharge pipe 18 is stored in the cylinder 20. Subsequently, the pressing shafts 25, 25 of each compression means 5, 5 are extended, and the front of the sealed container 3 is pressed by the required amount via the pressing plate 24. Then, the carbon dioxide discharge pipe 18 is closed and the residual gas discharge pipes 16, 16 are opened. Subsequently, referring to Figure 4(d), the pressing shafts 25, 25 of each compression means 5, 5 are further extended, and the front of the sealed container 3 is pressed all the way through the pressing plate 24. This causes the residual gas remaining in each gas supply space 11, 11 of the sealed container 3 to be discharged to the outside through the residual gas discharge pipes 16, 16.

[0031] Next, referring to Figure 4(e), the residual gas discharge pipes 16, 16 are closed. Subsequently, the pressing shafts 25, 25 of each compression means 5, 5 are returned to their initial positions, and the compressive load on the sealed container 3 by each compression means 5, 5 is released. At the same time, the gas supply pipes 14, 14 are opened, and the next gas to be processed is pumped through the gas supply pipes 14, 14 to each gas supply space 11, 11 of the sealed container 3. As a result, each gas supply space 11, 11 expands and returns to its initial shape, and the pressing plate 24 completes its retraction to its initial position. Subsequently, the carbon dioxide recovery process described above is repeated.

[0032] As described above, the carbon dioxide recovery device 1 according to this embodiment includes a sealed container 3 to which a gas to be treated containing carbon dioxide is supplied and which has compressible gas supply spaces 11, 11; carbon dioxide selective permeable membranes 4, 4 arranged inside the sealed container 3 and selectively permeate carbon dioxide from the gas to be treated supplied to the gas supply spaces 11, 11; and compression means 5 that compresses the gas supply spaces 11, 11 of the sealed container 3 and pressurizes the gas to be treated supplied to the gas supply spaces 11, 11 to the carbon dioxide selective permeable membranes 4, 4. As a result, the carbon dioxide recovery device 1 according to this embodiment can be configured compactly while ensuring carbon dioxide recovery efficiency. Consequently, the carbon dioxide recovery device 1 according to this embodiment can be installed on a CDM ship used in the CDM method. As mentioned above, the carbon dioxide recovery device 1 according to this embodiment has a compact installation area (size on a planar surface) of less than approximately 10 m (vertical direction) x approximately 10 m (width direction), preferably about 8 m (vertical direction) x approximately 4 m (width direction).

[0033] Furthermore, the carbon dioxide recovery device 1 according to this embodiment is compactly constructed and can be mounted on a CDM vessel used in the CDM method, making it particularly effective for recovering carbon dioxide from exhaust gases emitted from the CDM vessel. Thus, by using the carbon dioxide recovery device 1 according to this embodiment to recover carbon dioxide from the exhaust gases of a CDM vessel, the carbon dioxide recovered on the CDM vessel can be dissolved in cement grout, which is made by stirring cement and water. This allows the carbon dioxide to react with the cement grout and be fixed in the ground as a cement-improved pile containing calcium carbonate. In this way, the carbon dioxide recovery device 1 according to this embodiment is particularly effective because it allows the carbon dioxide recovered on the CDM vessel to be quickly fixed in the ground on-site without the need for transportation.

[0034] Furthermore, in the carbon dioxide recovery device 1 according to this embodiment, the sealed container 3 includes a carbon dioxide inlet space 10 positioned approximately in the center in the compression direction and provided between a pair of opposing carbon dioxide selective permeable membranes 4, 4, and gas supply spaces 11, 11 positioned on either side of the carbon dioxide inlet space 10 in the compression direction. When each gas supply space 11, 11 is compressed, the gas to be processed in each gas supply space 11, 11 is pumped to the pair of carbon dioxide selective permeable membranes 4, 4, and the carbon dioxide in the gas to be processed flows into and fills the carbon dioxide inlet space 10, thereby increasing the amount recovered per unit time and improving the carbon dioxide recovery efficiency.

[0035] Furthermore, in the carbon dioxide recovery device 1 according to this embodiment, a carbon dioxide concentration meter 6 is placed in the carbon dioxide inflow space 10 of the sealed container 3. By managing the detection results from the carbon dioxide concentration meter 6 over time, it is possible to identify problems such as damage or clogging of the carbon dioxide selective permeable membrane 4, and to determine when maintenance is needed. In addition, based on the detection results from the carbon dioxide concentration meter 6, it is possible to determine the concentration of carbon dioxide discharged from the carbon dioxide inflow space 10 to the outside, and the concentration of carbon dioxide that is either in the carbon dioxide inflow space 10 or directly utilized.

[0036] Furthermore, the compression means 5 employed in the carbon dioxide recovery device 1 according to this embodiment is composed of a press machine having an extendable and retractable pressing shaft 25, and its configuration is simplified, allowing the entire device to be made compact. In addition, in this embodiment, the pressing shaft 25 of the press machine, which serves as the compression means 5, compresses each gas supply space 11, 11 of the sealed container 3 via the pressing plate 24, so that each gas supply space 11, 11 can be compressed substantially uniformly in a planar manner rather than locally, and the pressure inside each gas supply space 11, 11 can be made substantially uniformly high throughout its entire area without bias.

[0037] Furthermore, this embodiment includes a first pumping step in which the gas to be treated is pumped to a pair of carbon dioxide selective permeable membranes 4, 4 via each gas supply space 11, 11 in the sealed container 3, and a second pumping step in which each gas supply space 11, 11 to which the gas to be treated is supplied is compressed by each compression means 5, 5, and the gas to be treated in each gas supply space 11, 11 is pumped to the pair of carbon dioxide selective permeable membranes 4, 4. These two-stage first and second pumping steps enable efficient pumping of the gas to be treated to the carbon dioxide selective permeable membranes 4, 4, further improving the carbon dioxide recovery efficiency.

[0038] The carbon dioxide recovery device 1 according to this embodiment is intended for recovering carbon dioxide from exhaust gases emitted from CDM vessels used in the CDM method. However, it can also be mounted on other work vessels used in offshore construction, particularly relatively large work vessels with limited space, such as dredgers, crane ships, and SCP vessels, to recover carbon dioxide from their exhaust gases. Furthermore, while this embodiment includes one carbon dioxide recovery device 1, multiple devices may be provided if there is sufficient space. Moreover, if the carbon dioxide recovery device 1 according to this embodiment can be installed, it may also be used to recover carbon dioxide from exhaust gases from equipment used in land-based construction, and is not limited to specific locations or environments. [Explanation of symbols]

[0039] 1 Carbon dioxide capture device, 3 Sealed container, 4 Carbon dioxide selective permeable membrane, 5 Compression means, 6 Carbon dioxide concentration meter, 10 Carbon dioxide inflow space, 11 Gas supply space, 25 Pressing shaft

Claims

1. A sealed container having a compressible gas supply space into which a gas to be treated, containing carbon dioxide, is supplied, A carbon dioxide selective permeable membrane is placed inside the sealed container and selectively permeates carbon dioxide from the gas to be treated supplied to the gas supply space, A compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane, Equipped with, The carbon dioxide recovery device is characterized in that the gas to be treated is exhaust gas discharged from a work vessel used for offshore construction.

2. A sealed container having a compressible gas supply space into which a gas to be treated, containing carbon dioxide, is supplied, A carbon dioxide selective permeable membrane is placed inside the sealed container and selectively permeates carbon dioxide from the gas to be treated supplied to the gas supply space, A compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane, Equipped with, The carbon dioxide selective permeable membrane is provided in a pair facing each other, A carbon dioxide recovery device characterized in that carbon dioxide flowing into the carbon dioxide inflow space between the pair of carbon dioxide selective permeable membranes is recovered to the outside from the sealed container.

3. A sealed container having a compressible gas supply space into which a gas to be treated, containing carbon dioxide, is supplied, A carbon dioxide selective permeable membrane is placed inside the sealed container and selectively permeates carbon dioxide from the gas to be treated supplied to the gas supply space, A compression means for compressing the gas supply space of the sealed container and pressurizing the gas to be treated supplied to the gas supply space to the carbon dioxide selective permeable membrane, Equipped with, A carbon dioxide recovery apparatus characterized in that, within the sealed container, a carbon dioxide concentration meter is positioned in the inflow space of separated carbon dioxide located downstream of the carbon dioxide selective permeable membrane in the flow direction of the gas to be treated.

4. A sealed container having a compressible gas supply space into which a gas to be treated, containing carbon dioxide, is supplied, A carbon dioxide selective permeable membrane is placed inside the sealed container and selectively permeates carbon dioxide from the gas to be treated supplied to the gas supply space, A compression means for compressing the gas supply space of the sealed container and for pressurizing the gas to be processed supplied to the gas supply space to the carbon dioxide selective permeable membrane, Equipped with, Within the sealed container, there is a carbon dioxide inflow space provided between a pair of opposing carbon dioxide selective permeable membranes, positioned approximately in the center in the compression direction. In the compression direction, the gas supply spaces are arranged so as to sandwich the carbon dioxide inflow space, A carbon dioxide capture device characterized by being equipped with the following features.

5. The compression means is comprised of a press machine having an extendable and retractable pressing shaft. The carbon dioxide recovery device according to any one of claims 1 to 4, characterized in that the gas supply space is compressed by the pressing shaft of the press machine.

6. A carbon dioxide capture method using a carbon dioxide selective permeable membrane that selectively transmits carbon dioxide, A first pumping step involves pumping exhaust gas containing carbon dioxide, emitted from a work vessel used for offshore construction, through a gas supply space in a sealed container to the carbon dioxide selective permeable membrane. A second pumping step involves compressing the gas supply space into which the exhaust gas is supplied, thereby pumping the exhaust gas in the gas supply space to the carbon dioxide selective permeable membrane. A method for capturing carbon dioxide, characterized by including [a specific component].

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