Carbon dioxide recovery device

Abstract

To provide a carbon dioxide recovery device having a more preferable structure for energy saving.SOLUTION: A carbon dioxide recovery device 1 according to the disclosure includes: an absorbent tank 10 for storing an absorbent made of a diamine compound with a cyclohexylamine group; a regenerator 20; and a liquid feeding pump 30 which suctions the absorbent from a bottom area of the absorbent tank 10 to send the absorbent to the regenerator 20. The regenerator 20 has: a sub-tank 21; a regeneration chamber 22 which introduces the absorbent sent from the sub-tank 21 and discharges the absorbent from a lower part; a collection material 23 which is disposed in the regeneration chamber 22 and collects solid deposits occurring from the absorbent due to absorption of carbon dioxide; and a heater 24 for heating the collection material 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to carbon dioxide capture devices. [Background technology]

[0002] Various methods have been proposed to capture carbon dioxide from exhaust gases and the atmosphere. One of the carbon dioxide capture methods, the chemical absorption method, is characterized by its high selectivity. In the chemical absorption method, carbon dioxide is captured as highly concentrated carbon dioxide by utilizing the property of a carbon dioxide absorption solution (hereinafter simply referred to as "absorption solution") that reacts with carbon dioxide at low temperatures and releases carbon dioxide at high temperatures.

[0003] A typical example of this type of carbon dioxide capture device is a two-tower type composed of an absorption tower and a regeneration tower. A two-tower type carbon dioxide capture device is typically configured such that carbon dioxide in the exhaust gas is absorbed by an absorption liquid in the absorption tower, the carbon dioxide is released from the absorption liquid that has absorbed the carbon dioxide in the regeneration tower, and the absorption liquid is circulated between the two towers (see, for example, Patent Document 1).

[0004] Conventionally, this type of carbon dioxide capture device has used monoethanolamine (MEA) or the like as an absorbing liquid, which needs to be heated to about 120°C when re-releasing carbon dioxide in a regeneration tower. Furthermore, typical absorbing liquids such as MEA typically absorb and release carbon dioxide in a liquid state (i.e., unlike isophoronediamine, which will be described later, MEA does not stabilize carbon dioxide as a solid precipitate even when reacting with carbon dioxide). Therefore, when circulating the absorbing liquid between the two, it is necessary to pump a large amount of the absorbing liquid and perform heat exchange during this process, thereby significantly adjusting the temperature of the absorbing liquid.

[0005] Therefore, in the carbon dioxide capture device according to the prior art, the absorption tower and the regeneration tower are of similar size, and the equipment is large. In addition, there is also the problem that the amount of energy required for the entire system is large because energy is also required to pump the absorption liquid. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-147171 [Non-patent literature]

[0007] [Non-Patent Document 1] Soichi Kikkawa, et al. "Direct Air Capture of CO2 Using a Liquid Amine-Solid Carbamic Acid Phase-Separation System Using Diamines Bearing an Aminocyclohexyl Group", ACS Environmental Au, August 2022,vol 2, pp354-pp362, Publication Date(Web):May 10, 2022,("URL: https: / / pubs.acs.org / doi / epdf / 10.1021 / acsenvironau.1c00065.pdf") Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, an absorbing liquid such as isophoronediamine that precipitates as a solid upon reaction with carbon dioxide has been proposed (see, for example, Non-Patent Document 1). Isophoronediamine is a type of diamine compound that has a cyclohexylamine group.

[0009] Generally, when an amine reacts with carbon dioxide, an unstable carbamic acid is formed. However, when a diamine compound containing a cyclohexylamine group reacts with carbon dioxide, it forms a solid carbamic acid, which precipitates as a solid. Isophoronediamine exhibits this characteristic prominently. This solid precipitate, a type of carbamic acid (hereinafter simply referred to as "solid precipitate"), can be selectively extracted from the absorption solution by phase separation. Furthermore, at temperatures as low as about 60°C, this solid precipitate re-releases the absorbed carbon dioxide and returns to the original isophoronediamine. In other words, by using isophoronediamine as the absorption solution in a carbon dioxide capture device, it is possible to easily absorb and fix carbon dioxide, and also to reduce the size of the carbon dioxide capture device.

[0010] However, in the current carbon dioxide capture devices, suitable device configurations using diamine compounds having a cyclohexylamine group, such as isophoronediamine, have not yet been fully investigated. In particular, in this type of carbon dioxide capture device, energy saving of the entire device is important from the viewpoint of carbon neutrality, but from this viewpoint, there is room for improvement in the current carbon dioxide capture devices.

[0011] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a carbon dioxide capture device having a more suitable configuration from the viewpoint of energy saving. [Means for solving the problem]

[0012] The present disclosure mainly solves the above-mentioned problems by: A carbon dioxide recovery device that uses a diamine compound having a cyclohexylamine group as an absorption liquid, an absorption liquid tank for storing the absorption liquid, introducing a gas to be separated containing carbon dioxide from the outside and bringing the gas into contact with the absorption liquid, thereby causing the carbon dioxide to be absorbed into the absorption liquid; a regenerator disposed between the regenerator and the absorption liquid tank so that the absorption liquid flows back; a liquid transfer pump that pumps up the absorption liquid from a bottom region of the absorption liquid tank and delivers it to the regenerator; Equipped with The regenerator comprises: a sub-tank for temporarily storing the absorption liquid delivered from the liquid delivery pump; a regeneration chamber into whose internal space the absorption liquid discharged from the sub-tank is introduced and from which the absorption liquid is discharged from the bottom; an adsorbent disposed in the regeneration chamber for adsorbing solid precipitates generated by the absorption of carbon dioxide from the absorption liquid; a heater that heats the adsorption material and causes the carbon dioxide to dissipate from the solid deposit; The carbon dioxide capture device comprises: [Effects of the Invention]

[0013] The carbon dioxide capture device according to the present disclosure is suitable from the viewpoint of energy conservation. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of a carbon dioxide capture device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a detailed configuration of a regenerator of a carbon dioxide capture device according to an embodiment of the present invention (solid deposit regeneration period). [Figure 3] FIG. 1 is a diagram showing a detailed configuration of a regenerator of a carbon dioxide capture device according to an embodiment of the present invention (solid precipitate capture period). DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0016] In the following, the terms "below" and "above" are used, and "below" and "above" mean "vertically below" and "vertically above", respectively.

[0017] <Configuration of Carbon Dioxide Capture Device 1> A carbon dioxide recovery apparatus according to one embodiment of the present invention (hereinafter referred to as "carbon dioxide recovery apparatus 1") will be described below.

[0018] FIG. 1 is a diagram showing an example of the overall configuration of a carbon dioxide capture device 1. As shown in FIG.

[0019] 2 and 3 are diagrams showing the detailed configuration of the regenerator 20 of the carbon dioxide capture device 1. During operation of the carbon dioxide capture device 1 according to this embodiment, the regenerator 20 alternately performs an operation related to a solid deposit capture period in which solid deposits are captured on the adsorption material 23, and an operation related to a solid deposit regeneration period in which the regenerator 20 heats and regenerates the solid deposits captured on the adsorption material 23. FIG. 2 shows the operating state during the solid deposit regeneration period. FIG. 3 shows the operating state during the solid deposit capture period.

[0020] The carbon dioxide capture device 1 includes an absorption liquid tank 10 that stores an absorption liquid, a regenerator 20 that dissipates carbon dioxide from the absorption liquid, a liquid feed pump 30 that sucks up the absorption liquid from the bottom region of the absorption liquid tank 10 and sends it to the regenerator 20, and a controller 100. The absorption liquid regenerated in the regenerator 20 is returned to the absorption liquid tank 10 through a pipe LL.

[0021] The carbon dioxide recovery device 1 according to this embodiment is a device that recovers carbon dioxide directly from the atmosphere.

[0022] In the carbon dioxide recovery device 1 according to this embodiment, the above-mentioned isophorone diamine is used as the absorbing liquid, and specifically, the absorbing liquid is made of a mixed liquid of isophorone diamine and water.

[0023] The solid precipitate of isophoronediamine (i.e., solid carbamic acid) is generated in the form of particles in the absorption liquid, but has the characteristic that the particles tend to aggregate together due to physical adsorptive forces such as van der Waals forces. Therefore, when the concentration of isophoronediamine in the absorption liquid is high, a large amount of highly viscous solid precipitate in an aggregated state may accumulate at the bottom of the absorption liquid tank 10, making it difficult to deliver the liquid using the liquid delivery pump 30. From this perspective, the absorption liquid is preferably a mixed liquid in which isophoronediamine is diluted to 1% to 30% with a solvent such as water.

[0024] The absorption liquid tank 10 functions as an absorption tower, stores unreacted absorption liquid, and is disposed in a substantially sealed state. The absorption liquid tank 10 has a gas inlet 11 at the bottom of the tank, through which a gas to be separated containing carbon dioxide (here, the atmosphere) is introduced from the outside. The gas to be separated introduced from the gas inlet 11 comes into contact with the absorption liquid in the absorption liquid tank 10 as it rises within the absorption liquid tank 10. As a result, carbon dioxide from the gas to be separated is selectively absorbed by the absorption liquid. The absorption liquid that has absorbed the carbon dioxide then becomes a solid precipitate and settles to the bottom of the tank (precipitate accumulation region 10a).

[0025] A partition plate 13 is disposed at the bottom of the absorption liquid tank 10, and an area intended for solid deposit deposition (hereinafter referred to as "deposit deposition area 10a") is formed on one side of the tank bottom across the partition plate 13, and an area intended for no solid deposit deposition (hereinafter referred to as "deposit non-deposit area 10b") is formed on the other side of the tank bottom across the partition plate 13. An intake port for a liquid feed pump 30 is disposed in the deposit deposition area 10a, and a gas inlet port 11 is disposed in the deposit non-deposit area 10b.

[0026] The partition plate 13 is formed so that the area it occupies in the deposit accumulation region 10a in a plan view narrows from top to bottom. That is, the carbon dioxide in the gas to be separated introduced from the gas inlet 11 comes into contact with the absorption liquid in the absorption liquid tank 10 and becomes a solid deposit as it rises from the deposit non-accumulation region 10b inside the absorption liquid tank 10. Then, this solid deposit sinks under its own weight, is guided by the partition plate 13, and is deposited on the deposit accumulation region 10a side.

[0027] A gas exhaust port 12 for exhausting gas to the outside is disposed at the top of the absorption liquid tank 10. From the gas exhaust port 12, CO2-free gas after carbon dioxide has been absorbed from the gas to be separated (here, the atmosphere) is exhausted.

[0028] The outside air, for example, compressed by an air pump 11a, flows into the gas inlet 11 of the absorption liquid tank 10. A filter 11b is provided in the flow path connected to the gas inlet 11, so that impurities contained in the air introduced into the absorption liquid tank 10 are removed.

[0029] The liquid feed pump 30 sucks up the absorption liquid from the deposit accumulation region 10a of the absorption liquid tank 10 and sends it to the regenerator 20. That is, the liquid feed pump 30 sucks up the absorption liquid from the portion of the deposit accumulation region 10a of the absorption liquid tank 10 where the concentration of solid deposits is high. Therefore, the liquid feed pump 30 can efficiently send the solid deposits to the regenerator 20.

[0030] Here, the liquid feed pump 30 is configured to pump the absorbing liquid from the deposit accumulation region 10a of the absorbing liquid tank 10 to a liquid drain port 30a disposed at a position above the liquid level in the absorbing liquid tank 10. The liquid drain port 30a of the liquid feed pump 30 extends in a substantially horizontal direction, and discharges the absorbing liquid pumped up by the liquid feed pump 30 into the sub-tank 21 of the regenerator 20.

[0031] Any type of liquid feed pump 30 may be used, but a mono pump, which is classified as a rotary positive displacement uniaxial eccentric screw pump, is particularly suitable. With this configuration, it is possible to more easily suck up the solid precipitate together with the absorption liquid from the precipitate accumulation region 10a of the absorption liquid tank 10.

[0032] Here, the operation state of the liquid feed pump 30 is controlled by the controller 100. The liquid feed pump 30 is controlled, for example, to be intermittently driven. More specifically, the liquid feed pump 30 is controlled to be in an inoperative state during the solid precipitate regeneration period (see FIG. 2), and to be in an operational state during the solid precipitate capture period (see FIG. 3). That is, during the solid precipitate capture period, the liquid feed pump 30 pumps the absorption liquid from the absorption liquid tank 10 and sends it to the regenerator 20, circulating the absorption liquid between the absorption liquid tank 10 and the regenerator 20. On the other hand, during the solid precipitate regeneration period, the liquid feed pump 30 is in an inoperative state, and therefore stops the circulation of the absorption liquid between the absorption liquid tank 10 and the regenerator 20.

[0033] The regenerator 20 includes a sub-tank 21, a regeneration chamber 22, a collection material 23, and a heater 24. The regenerator 20 has a housing, and these are disposed in a sealed space.

[0034] The drain port 30a of the liquid feed pump 30 is inserted into the sub-tank 21, and the absorbing liquid fed from the liquid feed pump 30 is introduced into the sub-tank 21. The sub-tank 21 temporarily stores the absorbing liquid fed from the liquid feed pump 30 and feeds the stored absorbing liquid to the regeneration chamber 22. Note that the solid precipitate sucked up from the absorbing liquid tank 10 by the liquid feed pump 30 and the absorbing liquid are both introduced into the sub-tank 21.

[0035] The sub-tank 21 has a discharge port 21a at the bottom of the tank for discharging the absorbing liquid, and the discharge port 21a of the sub-tank 21 and the absorbing liquid inlet 22a of the regeneration chamber 22 are connected via a substantially S-shaped absorbing liquid introduction pipe 20L. In other words, the absorbing liquid discharged from the sub-tank 21 moves from the discharge port 21a at the bottom of the sub-tank 21 to the regeneration chamber 22 via the absorbing liquid introduction pipe 20L. Here, the sub-tank 21 is disposed above the regeneration chamber 22. Therefore, the absorbing liquid stored in the sub-tank 21 moves toward the regeneration chamber 22 by the action of gravity.

[0036] The solid precipitate sent to the subtank 21 settles under its own weight and moves to the bottom of the tank. Then, the solid precipitate flows into the regeneration chamber 22 together with the absorbing liquid due to the flow of the absorbing liquid moving from the subtank 21 toward the regeneration chamber 22.

[0037] The absorbing liquid introduction pipe 20L according to this embodiment also serves to separate the internal space of the regeneration chamber 22 from the space in the sub-tank 21 and the stored absorbing liquid. That is, the absorbing liquid introduction pipe 20L prevents carbon dioxide released by the regeneration of the solid precipitate in the regeneration chamber 22 from returning to the sub-tank 21.

[0038] Specifically, the absorbing liquid introduction pipe 20L forms, for example, a substantially S-shaped flow path, and transports the absorbing liquid discharged from the discharge port 21a of the sub-tank 21 to the absorbing liquid introduction port 22a of the regeneration chamber 22. The absorbing liquid introduction pipe 20L includes, for example, a first guide section 20La that receives the absorbing liquid from the discharge port 21a of the sub-tank 21 and guides the absorbing liquid downward from the discharge port 21a, a second guide section 20Lb that guides the absorbing liquid upward from the terminal end of the first guide section 20La, and a third guide section 20Lc that guides the absorbing liquid downward from the terminal end of the second guide section 20Lb and then guides it to the absorbing liquid introduction port 22a of the regeneration chamber 22, thereby forming a substantially S-shaped flow path.

[0039] The height position T3 of the top of the second guide section 20Lb of the absorption liquid introduction pipe 20L is located below the height position T1 of the top of the sub-tank 21 and above the height position T2 of the bottom (discharge outlet 21a) of the sub-tank 21.

[0040] With this configuration, when the amount of absorbent liquid stored in the subtank 21 increases (i.e., when the liquid level in the subtank 21 exceeds the height position T3 of the uppermost part of the second guide part 20Lb), the absorbent liquid flows from the subtank 21 into the regeneration chamber 22 via the absorbent liquid introduction pipe 20L (Fig. 3). On the other hand, when the amount of absorbent liquid stored in the subtank 21 decreases (i.e., when the liquid level in the subtank 21 falls below the height position T3 of the uppermost part of the second guide part 20Lb), the absorbent liquid does not move from the subtank 21 to the regeneration chamber 22 side, but stops at an intermediate position in the second guide part 20Lb (Fig. 2).

[0041] In other words, the internal space of the regeneration chamber 22 is always isolated from the space in the sub-tank 21 and the stored absorption liquid by the absorption liquid in the absorption liquid introduction pipe 20L. This also makes it possible to prevent the air and gases such as water vapor from entering the internal space of the regeneration chamber 22.

[0042] As described above, during the solid precipitate collection period, the liquid feed pump 30 is in operation, so that the amount of absorbent stored in the sub-tank 21 increases, causing a flow of absorbent in the absorbent introduction pipe 20L. On the other hand, during the solid precipitate regeneration period, the liquid feed pump 30 is in operation, so that the amount of absorbent stored in the sub-tank 21 decreases, causing the flow of absorbent in the absorbent introduction pipe 20L to stop.

[0043] The regeneration chamber 22 is a chamber for capturing solid precipitates in the absorption liquid with the capture material 23 supported in the internal space and regenerating the solid precipitates. The regeneration chamber 22 forms a substantially sealed internal space.

[0044] The regeneration chamber 22 has an absorption liquid inlet 22a at its upper part for introducing the absorption liquid from the sub-tank 21, and an absorption liquid outlet 22b at its lower part for returning the absorption liquid to the absorption liquid tank 10. That is, the absorption liquid that flows into the absorption liquid inlet 22a of the regeneration chamber 22 flows downward within the regeneration chamber 22 and is discharged from the absorption liquid outlet 22b.

[0045] The absorbent discharge port 22b is connected to an absorbent return pipe LL that extends into the absorbent stored in the absorbent tank 10. The outlet of the absorbent return pipe LL is disposed in a deposit non-accumulation region 10b in the absorbent stored in the absorbent tank 10.

[0046] The regeneration chamber 22 also has a carbon dioxide exhaust port 22c at its top. That is, the carbon dioxide released in the regeneration chamber 22 due to the regeneration of the solid precipitate is exhausted to the outside from the carbon dioxide exhaust port 22c. Because the carbon dioxide released in the regeneration chamber 22 due to the regeneration of the solid precipitate does not return to the subtank 21 due to the presence of the absorption liquid introduction pipe 20L, all of the carbon dioxide is exhausted to the outside from the carbon dioxide exhaust port 22c.

[0047] Here, the regeneration chamber 22 is disposed so that its bottom is higher than the level of the absorption liquid in the absorption liquid tank 10. This is to prevent the adsorption material 23 in the regeneration chamber 22 from being immersed in the absorption liquid during the solid precipitate regeneration period (FIG. 2), and to prevent the absorption liquid from accumulating at the bottom of the regeneration chamber 22.

[0048] During the solid precipitate regeneration period, the introduction of the absorption liquid into the regeneration chamber 22 is stopped, and the absorption liquid in the regeneration chamber 22 is discharged from the absorption liquid discharge port 22b. At this time, the liquid level of the absorption liquid in the regeneration chamber 22 (or the absorption liquid discharge port 22b) and the liquid level of the absorption liquid in the absorption liquid tank 10 are both under atmospheric pressure, so the liquid level of the absorption liquid in the regeneration chamber 22 (absorption liquid discharge port 22b) is at the same height as the liquid level of the absorption liquid in the absorption liquid tank 10. Note that the internal space of the regeneration chamber 22 is typically under atmospheric pressure due to the presence of the carbon dioxide exhaust port 22c.

[0049] Therefore, if the bottom of the regeneration chamber 22 is lower than the liquid level in the absorption liquid tank 10, the absorption liquid will accumulate at the bottom of the regeneration chamber 22. When the absorption liquid accumulates at the bottom of the regeneration chamber 22, the carbon dioxide released by the regeneration of the solid precipitate in the regeneration chamber 22 will react again with the absorption liquid and return to the absorption liquid tank 10 via the absorption liquid outlet 22b. Furthermore, if the adsorbent 23 is heated by the heater 24 while immersed in the absorption liquid, the water in the absorption liquid will evaporate and mix with the carbon dioxide separated in the regeneration chamber 22.

[0050] From the same viewpoint, it is preferable that the bottom of the regeneration chamber 22 has an inclined shape in which the height decreases from the periphery of the absorbent discharge port 22 b toward the absorbent discharge port 22 b, thereby more effectively preventing the absorbent from accumulating at the bottom of the regeneration chamber 22.

[0051] The adsorbent 23 is disposed in the regeneration chamber 22 so as to block the flow path of the absorption liquid, and collects solid precipitates generated by the absorption of carbon dioxide from the absorption liquid. The adsorbent 23 is made of, for example, stainless steel mesh, stainless steel wool, or glass wool.

[0052] The adsorbent 23 is disposed, for example, in a plan view, so as to block the entire passage in the regeneration chamber 22. As a result, solid precipitates in the absorption liquid that flows in from the absorption liquid inlet 22a of the regeneration chamber 22 are captured by the adsorbent 23, and only the liquid mixture of isophoronediamine and water flows down through the gaps in the adsorbent 23 (and the heater 24) and returns to the absorption liquid tank 10 from the absorption liquid outlet 22b.

[0053] As described above, the solid precipitate of isophoronediamine has the property of being easily adsorbed by other substances. Furthermore, the solid precipitate is prone to aggregation among particles, and exists in a somewhat aggregated state even in the absorption liquid. Therefore, when the solid precipitate passes through the adsorbent 23, it does not flow down through gaps in the adsorbent 23, and is easily captured by the adsorbent 23.

[0054] The heater 24 is disposed in the regeneration chamber 22 adjacent to the adsorption material 23, and heats the adsorption material 23 to dissipate carbon dioxide from the solid precipitate. As the heater 24, for example, a heat exchanger using hot water or a sheath heater or the like is suitable.

[0055] The heater 24 preferably heats the trapping material 23 so that the temperature of the solid precipitate rises to about 80° C. This ensures a sufficient regeneration speed for the solid precipitate.

[0056] When the delivery of the absorption liquid from the liquid delivery pump 30 is stopped, the liquid level stabilizes at the level shown in Figure 2, and mainly only the solid precipitates are in contact with the periphery of the adsorption material 23 and the heater 24. That is, by starting heating with the heater 24 in this state, the heater 24 can intensively heat only the aggregated solid precipitates.

[0057] The controller 100 is, for example, a microcomputer including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), an input port, an output port, and the like.

[0058] The controller 100 controls the operation of the liquid pump 30 and the heater 24. When the carbon dioxide capture device 1 is in operation, the controller 100 alternately executes an operating state during a solid deposit regeneration period and an operating state during a solid deposit capture period at regular intervals based on the amount of solid deposit captured in the capture material 23.

[0059] Specifically, during the solid precipitate collection period, the controller 100 operates the liquid feed pump 30 and deactivates the heater 24, and during the solid precipitate regeneration period, the controller 100 deactivates the liquid feed pump 30 and activates the heater 24. That is, the controller 100 controls the liquid feed pump 30 and the heater 24 to be intermittently driven.

[0060] In the carbon dioxide recovery device 1 according to this embodiment, the adsorbent 23 in the regeneration chamber 22 is configured to capture the solid precipitate and return the solid precipitate to the original isophoronediamine, so the regenerator 20 does not require a tank for regenerating the absorbing liquid.

[0061] Furthermore, in the carbon dioxide recovery device 1 according to this embodiment, when carbon dioxide is released from the solid precipitate, the entire absorption liquid is not heated to a high temperature, and therefore there is no need to provide a cooling device for cooling the absorption liquid in the path returning the absorption liquid from the regenerator 20 to the absorption liquid tank 10.

[0062] <Operation of Carbon Dioxide Capture Device 1> Next, an example of the operation of separating and capturing carbon dioxide in the carbon dioxide capture device 1 will be described.

[0063] First, a description will be given of the operating state of the carbon dioxide capture device 1 during the solid precipitate capture period. During the solid precipitate capture period, the controller 100 operates the liquid pump 30 and deactivates the heater 24.

[0064] When the carbon dioxide capture device 1 is operated, first, external gas to be separated (here, atmospheric air) is pumped by an air pump 11a and flows into the gas inlet 11 of the absorption liquid tank 10. The gas to be separated introduced from the gas inlet 11 comes into contact with the absorbing liquid in the absorption liquid tank 10 as it rises inside the absorption liquid tank 10. As a result, carbon dioxide from the gas to be separated is selectively absorbed by the absorbing liquid. Then, the absorbing liquid that has absorbed the carbon dioxide becomes a solid precipitate and settles and accumulates in a precipitate accumulation region 10a at the bottom of the absorption liquid tank 10.

[0065] The absorption liquid having a high concentration of solid precipitates deposited in the bottom region of the absorption liquid tank 10 is pumped up by the liquid feed pump 30 and sent to the sub-tank 21 of the regenerator 20. When a certain amount of absorption liquid or more accumulates in the sub-tank 21, the absorption liquid moves from the discharge port 21a at the bottom of the sub-tank 21 through the absorption liquid introduction pipe 20L to the regeneration chamber 22. At this time, the solid precipitates sent to the sub-tank 21 settle under their own weight and are present at the bottom of the tank. Therefore, the solid precipitates sent to the sub-tank 21 flow into the regeneration chamber 22 together with the absorption liquid due to the flow of the absorption liquid.

[0066] The absorption liquid that flows in from the absorption liquid inlet 22a of the regeneration chamber 22 flows downward within the regeneration chamber 22 and is discharged from the absorption liquid outlet 22b. At this time, the solid precipitate in the absorption liquid is collected by the adsorbent 23, and only the liquid mixture of isophoronediamine and water flows down through the gaps in the adsorbent 23 and returns to the absorption liquid tank 10 from the absorption liquid outlet 22b. Since this state is maintained during the solid precipitate collection period, the solid precipitate that has formed in the absorption liquid tank 10 gradually accumulates on the adsorbent 23.

[0067] Next, the operating state of the carbon dioxide capture device 1 during the solid deposit regeneration period will be described.

[0068] When the solid precipitate has been sufficiently collected by the collection material 23, the controller 100 switches the liquid feed pump 30 to a non-operating state and switches the heater 24 to an operating state.

[0069] By switching the liquid feed pump 30 to a non-operating state, the reflux of the absorption liquid between the regenerator 20 and the absorption liquid tank 10 stops, the absorption liquid is discharged from the regeneration chamber 22, and the liquid level of the absorption liquid stabilizes at the liquid level shown in Fig. 2. In other words, a state is reached in which mainly only solid precipitates are in contact with the periphery of the adsorption material 23 and the heater 24.

[0070] In this state, heating by the heater 24 is started, and only the aggregated solid precipitate is heated intensively. Then, the gaseous carbon dioxide desorbed from the solid precipitate by heating flows toward the top of the regeneration chamber 22 and is exhausted from the carbon dioxide exhaust port 22c. In addition, the solid precipitate from which carbon dioxide has been desorbed returns to liquid isophoronediamine and returns to the absorption liquid tank 10 from the absorption liquid outlet 22b at the bottom of the chamber.

[0071] The carbon dioxide recovery device 1 repeats the above-described operations to separate and recover carbon dioxide from the gas to be separated (here, the atmosphere).

[0072] <Effects> As described above, the carbon dioxide recovery device 1 according to this embodiment has the following features: an absorption liquid tank (10) for storing an absorption liquid of a diamine compound having a cyclohexylamine group, and for introducing a gas to be separated containing carbon dioxide from the outside and bringing the gas into contact with the absorption liquid, thereby causing the carbon dioxide to be absorbed into the absorption liquid; a regenerator (20) disposed between itself and the absorption liquid tank (10) so that the absorption liquid flows back; a liquid pump 30 that sucks up the absorption liquid from the bottom region of the absorption liquid tank 10 and sends it to the regenerator 20; Equipped with The regenerator 20 is a sub-tank 21 for temporarily storing the absorbing liquid delivered from the liquid delivery pump 30; a regeneration chamber 22 that introduces the absorbing liquid discharged from the sub-tank 21 into its internal space and discharges the absorbing liquid from the bottom; an adsorbent 23 disposed in the regeneration chamber 22 for collecting solid precipitates generated by the absorption of carbon dioxide from the absorption liquid; a heater 24 that heats the trapping material 23 and causes carbon dioxide to dissipate from the solid deposit; It has.

[0073] According to the carbon dioxide capture device 1 of this embodiment, the solid precipitates that have precipitated in the absorbing solution due to the absorption of carbon dioxide are collected in one place, and the solid precipitates can be concentrated and heated to a high temperature in a state where they are aggregated as much as possible. This makes it possible to separate and capture carbon dioxide from the absorbing solution with less energy.

[0074] Furthermore, according to the carbon dioxide capture device 1 of this embodiment, there is no need to provide a tank for storing the absorption liquid to be regenerated in the regenerator 20, and there is no need to provide a cooling device for cooling the absorption liquid in the path that returns the absorption liquid from the regenerator 20 to the absorption liquid tank 10. This makes it possible to reduce the size of the entire device compared to carbon dioxide capture devices according to conventional techniques.

[0075] (Other embodiments) The present invention is not limited to the above-described embodiment, and various modifications are possible.

[0076] For example, in the above embodiment, the carbon dioxide capture device 1 is used as a device for capturing carbon dioxide from the atmosphere. However, the carbon dioxide capture device 1 can also be used as a device for capturing carbon dioxide from exhaust gas.

[0077] In the above embodiment, a heat exchanger using hot water or a sheathed heater is used as an example of the heater 24. However, the heater 24 does not necessarily have to be a contact heating type, and a non-contact heater using microwave heating or the like may also be used.

[0078] In the above embodiment, a substantially S-shaped flow path is shown as an example of the absorption liquid introduction pipe 20L. However, the absorption liquid introduction pipe 20L does not necessarily have to be S-shaped as long as it constitutes a flow path that guides the absorption liquid discharged from the sub-tank 21 downward, upward, and downward in this order, and then transports it to the regeneration chamber 22.

[0079] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. [Industrial Applicability]

[0080] The carbon dioxide capture device according to the present disclosure is suitable from the viewpoint of energy conservation. [Explanation of symbols]

[0081] 1. Carbon dioxide capture device 10 Absorbent tank 10a Precipitate deposition area 10b Precipitate non-deposition area 11 Gas inlet 11a Air pump 11b filter 12 Gas exhaust port 13 Divider 20 Regenerator 20L absorption liquid introduction pipe 20La 1st Information Department 20Lb 2nd guide section 20Lc 3rd guide section 21 Subtank 21a Outlet 22 Regeneration Chamber 22a Absorbent liquid inlet 22b Absorption liquid outlet 22c Carbon dioxide exhaust vent 23 Collection material 24 Heater 30 Liquid transfer pump 30a drain port 100 Controllers LL Piping

Claims

1. A carbon dioxide recovery device that uses a diamine compound having a cyclohexylamine group as an absorption liquid, an absorption liquid tank for storing the absorption liquid, introducing a gas to be separated containing carbon dioxide from the outside and bringing the gas into contact with the absorption liquid, thereby causing the carbon dioxide to be absorbed into the absorption liquid; a regenerator disposed between the regenerator and the absorption liquid tank so that the absorption liquid flows back; a liquid transfer pump that pumps up the absorption liquid from a bottom region of the absorption liquid tank and delivers it to the regenerator; Equipped with The regenerator comprises: a sub-tank for temporarily storing the absorption liquid delivered from the liquid delivery pump; a regeneration chamber into whose internal space the absorption liquid discharged from the sub-tank is introduced and from which the absorption liquid is discharged from the bottom; an adsorbent disposed in the regeneration chamber for adsorbing solid precipitates generated by the absorption of carbon dioxide from the absorption liquid; a heater that heats the adsorption material and causes the carbon dioxide to dissipate from the solid deposit; A carbon dioxide capture device comprising:

2. the sub-tank is disposed above the regeneration chamber so as to discharge the absorption liquid from the bottom of the sub-tank; The sub-tank and the regeneration chamber are connected via a pipe for introducing an absorption liquid. The carbon dioxide capture device according to claim 1 .

3. The absorption liquid introduction pipe includes a first guide section that receives the absorption liquid from the discharge port of the sub-tank and guides the absorption liquid downward from the discharge port, a second guide section that guides the absorption liquid upward from a terminal end of the first guide section, and a third guide section that guides the absorption liquid downward from a terminal end of the second guide section and then transports it to the absorption liquid introduction port of the regeneration chamber. The carbon dioxide capture device according to claim 2 .

4. The height position of the uppermost part of the second guide part of the absorption liquid introduction pipe is located lower than the height position of the uppermost part of the sub-tank and higher than the height position of the lowermost part of the sub-tank. The carbon dioxide capture device according to claim 3 .

5. a control unit for controlling the operation of the liquid feed pump and the heater; The control unit alternately sets a first period for capturing the solid precipitate and a second period for regenerating the solid precipitate while the carbon dioxide capture device is in operation, and during the first period, sets the liquid feed pump in an operating state and the heater in an inoperable state, and during the second period, sets the liquid feed pump in an inoperable state and the heater in an operating state. The carbon dioxide capture device according to claim 1 .

6. The regeneration chamber is disposed so that its bottom is higher than the liquid level of the absorption liquid in the absorption liquid tank. The carbon dioxide capture device according to claim 1 .

7. The bottom of the regeneration chamber has a sloped shape that decreases in height from the periphery of the absorption liquid discharge port toward the absorption liquid discharge port. The carbon dioxide capture device according to claim 6.

8. The regeneration chamber has a carbon dioxide exhaust port at its top. The carbon dioxide capture device according to claim 1 .

9. The collection material is made of stainless steel mesh, stainless steel wool, or glass wool. The carbon dioxide capture device according to claim 1 .

10. The diamine compound is isophoronediamine. The carbon dioxide capture device according to claim 1 .

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