Carbon dioxide capture system and method for operating the carbon dioxide capture system

Abstract

This carbon dioxide recovery system comprises an absorption tower, a regeneration tower, a rich liquid line, a lean liquid line, a heat exchange unit, and a heating fluid supply unit. The absorption tower brings a carbon dioxide–containing gas that contains carbon dioxide into contact with an absorption liquid capable of absorbing carbon dioxide, thereby generating a rich liquid that is the absorption liquid in which the carbon dioxide in the carbon dioxide–containing gas has been absorbed. The regeneration tower releases carbon dioxide from the rich liquid by heating the rich liquid and generates a lean liquid that is the absorption liquid from which the carbon dioxide has been released. The rich liquid line guides the rich liquid from the absorption tower to the regeneration tower. The lean liquid line guides the lean liquid from the regeneration tower to the absorption tower. The heat exchange unit causes the lean liquid flowing through the lean liquid line to exchange heat with the absorption liquid, which differs in temperature from the lean liquid flowing through the lean liquid line. The heating fluid supply unit can supply a heating fluid that warms the heat exchange unit to the heat exchange unit.

Description

Carbon dioxide capture system

[0001] The present disclosure relates to carbon dioxide capture systems.

[0002] Patent Document 1 discloses a carbon dioxide capture system that captures carbon dioxide by bringing a gas containing carbon dioxide into contact with an absorption liquid. The carbon dioxide capture system in Patent Document 1 includes an absorption tower and a regeneration tower. The absorption tower causes the absorption liquid to absorb carbon dioxide. The regeneration tower heats the absorption liquid that has absorbed carbon dioxide in the absorption tower, causing the carbon dioxide to be released from the absorption liquid. The absorption liquid from which carbon dioxide has been released in the regeneration tower is returned to the absorption tower and used to absorb carbon dioxide.

[0003] JP 2012-000539 A

[0004] Carbon dioxide capture systems such as those described in Patent Document 1 often include a heat exchanger, such as a plate heat exchanger, to recover heat from the absorption solution that has released carbon dioxide in the regeneration tower. Such heat exchangers are maintained at a high temperature during operation of the carbon dioxide capture system, but their temperature drops to a low temperature when operation is stopped. In other words, when the carbon dioxide capture system is repeatedly started and stopped, the heat exchanger repeatedly goes through high and low temperature states. This places a strain on components of the heat exchanger, such as gaskets, and may result in damage to the heat exchanger components earlier than expected.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a carbon dioxide capture system that can reduce the burden on components of a heat exchanger.

[0006] According to one aspect of the present disclosure, a carbon dioxide capture system includes an absorption tower, a regeneration tower, a rich liquid line, a lean liquid line, a heat exchanger, and a heated fluid supply unit. The absorption tower produces a rich liquid, which is an absorption liquid that has absorbed carbon dioxide from the carbon dioxide-containing gas, by bringing a carbon dioxide-containing gas containing carbon dioxide into contact with an absorption liquid capable of absorbing carbon dioxide. The regeneration tower heats the rich liquid to release carbon dioxide from the rich liquid, producing a lean liquid, which is an absorption liquid from which the carbon dioxide has been released. The rich liquid line guides the rich liquid from the absorption tower to the regeneration tower. The lean liquid line guides the lean liquid from the regeneration tower to the absorption tower. The heat exchanger exchanges heat between the lean liquid flowing through the lean liquid line and an absorption liquid having a different temperature from the lean liquid flowing through the lean liquid line. The heated fluid supply unit is capable of supplying a heated fluid that heats the heat exchanger to the heat exchanger.

[0007] According to the carbon dioxide capture system according to the present disclosure, the burden on the components of the heat exchanger can be reduced.

[0008] FIG. 1 is a diagram showing a schematic configuration of a carbon dioxide capture system according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing a hardware configuration of a control device of a carbon dioxide capture system according to an embodiment of the present disclosure. FIG. 3 is a functional block diagram of a control device according to the first embodiment of the present disclosure. FIG. 4 is a flowchart of an operation method of a carbon dioxide capture system according to an embodiment of the present disclosure. FIG. 5 is a diagram showing a first state of a carbon dioxide capture system according to the first embodiment of the present disclosure. FIG. 6 is a diagram showing a transition state of a carbon dioxide capture system according to the first embodiment of the present disclosure. FIG. 7 is a diagram showing a second state of a carbon dioxide capture system according to the first embodiment of the present disclosure. FIG. 8 is a functional block diagram of a control device according to the second embodiment of the present disclosure. FIG. 9 is a diagram showing a first state of a carbon dioxide capture system according to the second embodiment of the present disclosure. FIG. 10 is a diagram showing a transition state of a carbon dioxide capture system according to the second embodiment of the present disclosure.

[0009] Hereinafter, a carbon dioxide capture system according to an embodiment of the present disclosure will be described with reference to the drawings. <First Embodiment> The carbon dioxide capture system according to the first embodiment captures carbon dioxide from a carbon dioxide-containing gas that contains carbon dioxide. Examples of the carbon dioxide-containing gas include exhaust gas from devices that combust fuel, such as gas turbines, internal combustion engines, and boilers.

[0010] Fig. 1 is a diagram showing a schematic configuration of a carbon dioxide capture system according to a first embodiment of the present disclosure. As shown in Fig. 1, the carbon dioxide capture system 100 according to the first embodiment includes an absorption tower 11, a regeneration tower 12, a rich liquid line 13, a lean liquid line 14, a heat exchange unit 15, a heated fluid supply unit 16, heat exchange unit bypass lines 17A and 17B, and a control device 18.

[0011] The absorption tower 11 produces a rich liquid R by bringing a carbon dioxide-containing gas G containing carbon dioxide into contact with an absorbing liquid. The absorbing liquid is capable of absorbing carbon dioxide through contact with the carbon dioxide-containing gas G. The rich liquid R is an absorbing liquid that has absorbed carbon dioxide from the carbon dioxide-containing gas G. The carbon dioxide-containing gas G is introduced into the absorption tower 11 using a blower (not shown) or the like. An example of the absorbing liquid is an amine-based absorbing liquid that absorbs carbon dioxide by chemical absorption. An example of an amine-based absorbing liquid is MEA (monoethanolamine). The absorption tower 11 is provided with a filler (not shown) made of an iron-based metal material or the like inside to increase the contact area.

[0012] The carbon dioxide-containing gas G introduced into the absorption tower 11 comes into contact with an absorbing liquid (lean liquid Le) sprayed from the top of the absorption tower 11 using a nozzle or the like. As a result, the carbon dioxide in the carbon dioxide-containing gas G is absorbed by the absorbing liquid (lean liquid Le), and the absorbing liquid becomes a rich liquid R. The remaining treated gas Gp from which the carbon dioxide has been absorbed by the absorbing liquid is discharged from the top of the absorption tower 11.

[0013] The carbon dioxide-containing gas G may be at a high temperature, for example, when it is exhaust gas generated by the combustion of fuel. In this case, the carbon dioxide-containing gas G may be introduced into the absorption tower 11 after its temperature has been lowered. As a device for lowering the temperature of the carbon dioxide-containing gas G, a cooling tower (not shown) that brings the carbon dioxide-containing gas G into contact with cooling water or the like can be used.

[0014] The absorption tower 11 of this embodiment has a scrubbing section 21 that scrubs the gas Gp to be treated with scrubbing water before the gas Gp is ​​discharged to the outside. The scrubbing section 21 captures the absorbing solution and the like contained in the gas Gp to be treated with scrubbing water inside the absorption tower 11. Although the absorption tower 11 of this embodiment has the scrubbing section 21 therein, the present invention is not limited to this configuration. For example, the scrubbing section 21 may be replaced with a scrubbing tower (not shown) provided outside the absorption tower 11.

[0015] The regeneration tower 12 generates lean solution Le, which is an absorption solution from which carbon dioxide has been released. In other words, the regeneration tower 12 releases carbon dioxide from rich solution R, which is an absorption solution that has absorbed carbon dioxide, making it reusable as an absorption solution that can absorb carbon dioxide. The regeneration tower 12 releases carbon dioxide by heating the rich solution R. Note that a filler (not shown) made of an iron-based metal material or the like is provided inside the regeneration tower 12.

[0016] More specifically, the rich liquid R discharged from the upper side of the regenerator 12 into the interior of the tower releases carbon dioxide by being heated by steam from the lower part of the regenerator 12, and becomes lean liquid Le from which almost all of the carbon dioxide has been removed by the time it flows downward to the bottom of the regenerator 12. A steam heating system 22 for heating the lean liquid Le is connected to the regenerator 12 in this embodiment. The steam heating system 22 includes a reboiler 23 and a circulation pipe 24. The reboiler 23 uses steam supplied from the outside as a heat source to heat the absorption liquid supplied to the regenerator 12 as the lean liquid Le. The circulation pipe 24 guides the absorption liquid as the lean liquid Le accumulated in the lower part of the regenerator 12 to the reboiler 23 and returns the lean liquid Le containing steam generated by heating in the reboiler 23 to the interior of the regenerator 12. As described above, the steam generated by the reboiler 23 heating the lean liquid Le heats the rich liquid R flowing from the upper side of the regeneration tower 12 inside the regeneration tower 12 .

[0017] The carbon dioxide gas released from the rich liquid R is discharged from the top of the regenerator 12. The absorbing liquid as the lean liquid Le returned to the regenerator 12 by the steam heating system 22 accumulates in the lower part of the regenerator 12. The lean liquid Le accumulated in the lower part of the regenerator 12 is sent to the absorption tower 11 via the lean liquid line 14.

[0018] Here, the carbon dioxide capture system 100 exemplified in this embodiment includes a capture unit 20. The capture unit 20 captures gaseous carbon dioxide separated in the regeneration tower 12. The capture unit 20 includes a condenser 20a, a reflux tower 20b, a reflux piping 20c, and a reflux pump 20d. The carbon dioxide gas discharged from the regeneration tower 12 through the reflux piping 20c contains absorbing liquid mist, gasified absorbing liquid, and the like. Therefore, the capture unit 20 condenses the absorbing liquid using the condenser 20a and separates the absorbing liquid from the carbon dioxide using the reflux tower 20b. The carbon dioxide gas captured by the reflux tower 20b is stored in, for example, a carbon dioxide capture tank (not shown). Meanwhile, the absorbing liquid separated by the reflux tower 20b is returned to the regeneration tower 12 by the reflux pump 20d. The capture unit 20 may be provided as needed and may be omitted, for example.

[0019] The rich liquid line 13 guides the rich liquid R from the absorption tower 11 to the regeneration tower 12. The rich liquid line 13 of this embodiment includes a tubular rich liquid supply pipe 26 that forms a flow path through which the rich liquid R flows, a first pump 27 for sending the rich liquid R to the regeneration tower 12, and a first valve 28 and a second valve 29 that open and close the flow path in the rich liquid supply pipe 26.

[0020] The lean liquid line 14 guides the lean liquid Le from the regenerator 12 to the absorber 11. The lean liquid line 14 of the present embodiment includes a tubular lean liquid supply pipe 31 that forms a flow path for the lean liquid Le, a second pump 32 for sending the lean liquid Le to the absorber 11, and a third valve 33 and a fourth valve 34 that open and close the flow path in the lean liquid supply pipe 31. The first valve 28, the second valve 29, the third valve 33, and the fourth valve 34 are control valves that can be opened and closed by a control device 18, which will be described later. Note that the first valve 28, the second valve 29, the third valve 33, and the fourth valve 34 may be capable of adjusting the valve opening degree in addition to being controlled to be opened and closed.

[0021] The heat exchange unit 15 exchanges heat between the lean liquid Le flowing through the lean liquid line 14 and an absorbing liquid having a different temperature from the lean liquid Le flowing through the lean liquid line 14. The heat exchange unit 15 of this embodiment is connected to both the rich liquid supply pipe 26 and the lean liquid supply pipe 31. In other words, the heat exchange unit 15 of this embodiment is capable of exchanging heat between the rich liquid R flowing through the rich liquid supply pipe 26 of the rich liquid line 13 and the lean liquid Le flowing through the lean liquid supply pipe 31 of the lean liquid line 14. The heat exchange unit 15 becomes hot (for example, approximately 90°C to 120°C) when the carbon dioxide capture system 100 is operating, in other words, when carbon dioxide is being captured from the flue gas G by the carbon dioxide capture system 100.

[0022] In this embodiment, the first valve 28 of the rich liquid line 13 is disposed at a position closer to the absorber 11 than the heat exchanger 15. The second valve 29 of the rich liquid line 13 is disposed at a position closer to the regenerator 12 than the heat exchanger 15. In other words, the heat exchanger 15 is provided midway along the rich liquid supply pipe 26 between the first valve 28 and the second valve 29. The first pump of the rich liquid line 13 is disposed between the first valve 28 and the absorber 11.

[0023] In the present embodiment, the third valve 33 of the lean liquid line 14 is disposed at a position closer to the regenerator 12 than the heat exchanger 15. The fourth valve 34 of the lean liquid line 14 is disposed at a position closer to the absorber 11 than the heat exchanger 15. That is, the heat exchanger 15 is provided midway in the lean liquid supply piping 31 between the third valve 33 and the fourth valve 34. The second pump 32 of the lean liquid line 14 is disposed between the fourth valve 34 and the absorber 11. However, the location of the second pump 32 is not limited to the above location as long as it is midway in the lean liquid supply piping 31.

[0024] The lean liquid line 14 of the present embodiment further includes a cooling device 35 between the second pump 32 and the absorption tower 11. The cooling device 35 further cools the lean liquid Le that has undergone heat exchange with the rich liquid R by the heat exchange unit 15.

[0025] The heating fluid supply unit 16 is capable of supplying the heating fluid Lh to the heat exchange unit 15 to heat the heat exchange unit 15. The heating fluid supply unit 16 includes a vessel 37, a heating unit 38, and a circulation line 39. The vessel 37 is a container that stores the heating fluid Lh. The heating unit 38 heats the heating fluid Lh. In this embodiment, the heating unit 38 is attached to the vessel 37 and heats the heating fluid Lh in the vessel 37 to a predetermined temperature (e.g., 30°C or higher).

[0026] The circulation line 39 supplies the heated fluid Lh to the heat exchange unit 15 and returns the heated fluid Lh supplied to the heat exchange unit 15 to the vessel 37. The circulation line 39 in this embodiment includes a heated fluid supply line 41 and a heated fluid return line 42. The heated fluid supply line 41 supplies the heated fluid Lh from the vessel 37 to the heat exchange unit 15. The heated fluid supply line 41 includes a main supply pipe 43, a heated fluid supply pump 44, a first supply pipe 45, a second supply pipe 46, a fifth valve 47, and a sixth valve 48.

[0027] The main supply pipe 43 guides the heated fluid Lh in the vessel 37 to the outside of the vessel 37. The first supply pipe 45 and the second supply pipe 46 are each connected to the main supply pipe 43. In other words, the first supply pipe 45 and the second supply pipe 46 are each branched and connected to the main supply pipe 43. The heated fluid Lh flowing through the main supply pipe 43 is divided into the first supply pipe 45 and the second supply pipe 46 and flows therethrough.

[0028] The first supply pipe 45 communicates the main supply pipe 43 with the rich liquid supply pipe 26 of the rich liquid line 13. The first supply pipe 45 is connected to the rich liquid supply pipe 26 between the first valve 28 and the heat exchange unit 15. The second supply pipe 46 communicates the main supply pipe 43 with the lean liquid supply pipe 31 of the lean liquid line 14. The second supply pipe 46 is connected to the lean liquid supply pipe 31 between the third valve 33 and the heat exchange unit 15. The fifth valve 47 is provided midway along the first supply pipe 45 and opens and closes the flow path of the first supply pipe 45. The sixth valve 48 is provided midway along the second supply pipe 46 and opens and closes the flow path of the second supply pipe 46.

[0029] The heated fluid return line 42 returns the heated fluid Lh supplied by the heated fluid supply line 41 to the inside of the vessel 37. The heated fluid return line 42 includes a first return pipe 49, a second return pipe 50, a seventh valve 51, an eighth valve 52, and a main return pipe 53.

[0030] The first return pipe 49 connects the rich liquid supply pipe 26 of the rich liquid line 13 to the main return pipe 53. The first return pipe 49 is connected to the rich liquid supply pipe 26 between the heat exchange unit 15 and the second valve 29.

[0031] The second return pipe 50 connects the lean liquid supply pipe 31 of the lean liquid line 14 to the main return pipe 53. The second return pipe 50 is connected to the lean liquid supply pipe 31 between the heat exchange unit 15 and the fourth valve 34.

[0032] The main return pipe 53 connects the first return pipe 49 and the second return pipe 50 to the vessel 37. The heated fluid Lh flowing through the first return pipe 49 and the heated fluid Lh flowing through the second return pipe 50 join together and return to the inside of the vessel 37 via the main return pipe 53.

[0033] The seventh valve 51 is provided in the first return pipe 49 and opens and closes the flow path of the first return pipe 49. The eighth valve 52 is provided in the second return pipe 50 and opens and closes the flow path of the second return pipe 50. Note that instead of the heated fluid supply pump 44, a heated fluid return pump (not shown) may be provided to return the heated fluid Lh flowing in the heated fluid return line 42 to the vessel 37.

[0034] The heat exchanger bypass lines 17A and 17B divert the absorbing liquid flowing through the rich liquid line 13 from the absorber 11 to the regenerator 12 and the absorbing liquid flowing through the lean liquid line 14 from the regenerator 12 to the absorber 11, respectively, so as not to flow into the heat exchanger 15. The heat exchanger bypass line 17A includes a first bypass pipe 55 and a ninth valve 57. The first bypass pipe 55 connects the rich liquid supply pipe 26 between the absorber 11 and the first valve 28 with the rich liquid supply pipe 26 between the second valve 29 and the regenerator 12. The ninth valve 57 opens and closes the flow path of the first bypass pipe 55. The heat exchanger bypass line 17B includes a second bypass pipe 56 and a tenth valve 58. The second bypass pipe 56 connects the lean liquid supply pipe 31 between the regenerator 12 and the third valve 33 with the lean liquid supply pipe 31 between the fourth valve 34 and the absorber 11. The tenth valve 58 opens and closes the flow path of the second bypass pipe 56 .

[0035] (Hardware Configuration Diagram) FIG. 2 is a diagram showing the hardware configuration of a control device of a carbon dioxide capture system according to an embodiment of the present disclosure.

[0036] The control device 18 is capable of controlling the operation of a plurality of control valves, namely, a first valve 28, a second valve 29, a third valve 33, a fourth valve 34, a fifth valve 47, a sixth valve 48, a seventh valve 51, an eighth valve 52, a ninth valve 57, and a tenth valve 58. The control device 18 is further capable of switching on and off the heating fluid supply pump 44. As shown in FIG. 2 , the control device 18 is a computer including a CPU (Central Processing Unit) 61, a ROM (Read Only Memory) 62, a RAM (Random Access Memory) 63, a storage 64, and a signal transmission / reception module 65.

[0037] 3 is a functional block diagram of the control device according to the first embodiment of the present disclosure. As shown in Fig. 3, the CPU 61 of the control device 18 executes a program stored in advance in a storage device such as a ROM 62 or a storage 64, thereby realizing the functional configurations of a signal input unit 70, a valve control unit 71, a pump control unit 72, and an output unit 73.

[0038] The signal input unit 70 receives information related to the operating status of the carbon dioxide capture system 100 via the signal transmission / reception module 65, which is hardware. The valve control unit 71 generates control signals for controlling the operation of the first valve 28, the second valve 29, the third valve 33, the fourth valve 34, the fifth valve 47, the sixth valve 48, the seventh valve 51, the eighth valve 52, the ninth valve 57, and the tenth valve 58, based on the information related to the operating status of the carbon dioxide capture system 100 received by the signal input unit 70.

[0039] The pump control unit 72 generates a control signal for controlling the operation of the heated fluid supply pump 44, based on information regarding the operating status of the carbon dioxide capture system 100 received by the signal input unit 70. The output unit 73 outputs the control signals generated by the valve control unit 71 and the pump control unit 72 to the first valve 28, the second valve 29, the third valve 33, the fourth valve 34, the fifth valve 47, the sixth valve 48, the seventh valve 51, the eighth valve 52, the ninth valve 57, the tenth valve 58, and the heated fluid supply pump 44, respectively, via the signal transmitting / receiving module 65.

[0040] The valve control unit 71 and the pump control unit 72 of the control device 18 are capable of switching between a first state in which the heating fluid Lh is supplied to the heat exchange unit 15 to heat the heat exchange unit 15, and a second state in which the absorption liquid from the absorption tower 11 and the absorption liquid from the regeneration tower 12 are each supplied to the heat exchange unit 15 to perform heat exchange. Switching between the first state and the second state can be performed based on, for example, information related to the discharge status of the flue gas G. Switching between the first state and the second state may also be performed based on an operation input by an operator. The valve control unit 71 and the pump control unit 72 of the present embodiment further control a transition state between the first state and the second state in which the supply of the heating fluid Lh to the heat exchange unit 15 continues while the recovery of carbon dioxide from the flue gas G is started.

[0041] (Method of operating a carbon dioxide capture system) Fig. 4 is a flowchart of a method of operating a carbon dioxide capture system according to an embodiment of the present disclosure. Fig. 5 is a diagram showing a first state of the carbon dioxide capture system according to the first embodiment of the present disclosure. Fig. 6 is a diagram showing a transition state of the carbon dioxide capture system according to the first embodiment of the present disclosure. Fig. 7 is a diagram showing a second state of the carbon dioxide capture system according to the first embodiment of the present disclosure.

[0042] 4 , the method for operating the carbon dioxide capture system of this embodiment performs a heating step S01 and a transition step S04 after the absorption tower 11 and the regeneration tower 12 are shut down and before they are restarted. In the heating step S01, a heating fluid Lh is supplied to the heat exchange unit 15 to set the heat exchange unit 15 in a first state where it is heated. In the transition step S04, when starting operation of the absorption tower 11 and the regeneration tower 12 from a stopped state, the supply of heating fluid Lh to the heat exchange unit 15 is continued, and a transition state is set in which the absorption liquid circulating between the absorption tower 11 and the regeneration tower 12 flows so as to bypass the heat exchange unit 15.

[0043] (First State) When the exhaust gas G is not introduced into the absorption tower 11 and the absorption tower 11 and the regeneration tower 12 are not operating, the control device 18 controls the first valve 28, the second valve 29, the third valve 33, the fourth valve 34, the fifth valve 47, the sixth valve 48, the seventh valve 51, the eighth valve 52, the ninth valve 57, and the tenth valve 58 to put the carbon dioxide capture system 100 into the first state. That is, as shown in Fig. 5 , the control device 18 closes the first valve 28, the second valve 29, the third valve 33, the fourth valve 34, the ninth valve 57, and the tenth valve 58, and opens the fifth valve 47, the sixth valve 48, the seventh valve 51, and the eighth valve 52. The control device 18 also operates the heated fluid supply pump 44 (heating process).

[0044] As a result, the heating fluid Lh in the vessel 37 circulates between the heat exchange unit 15 and the vessel 37 via the circulation line 39, and the heat of the heating fluid Lh heats the heat exchange unit 15. Specifically, the heating fluid Lh in the vessel 37 is introduced into the main supply pipe 43 of the heating fluid supply line 41, and is then branched into a first supply pipe 45 and a second supply pipe 46.

[0045] The heated fluid Lh that has flowed into the first supply pipe 45 flows from the first supply pipe 45 into the heat exchange section 15 via the rich liquid supply pipe 26 that is closer to the absorption tower 11 than the heat exchange section 15. The heated fluid Lh that has flowed into this heat exchange section 15 heats the heat exchange section 15 as it passes through the heat exchange section 15, and is discharged into the rich liquid supply pipe 26 that is closer to the regenerator 12 than the heat exchange section 15. The heated fluid Lh that has been discharged into the rich liquid supply pipe 26 that is closer to the regenerator 12 returns to the vessel 37 via the first return pipe 49 and the main return pipe 53.

[0046] The heated fluid Lh that has flowed into the second supply pipe 46 flows from the second supply pipe 46 into the heat exchange section 15 via the lean liquid supply pipe 31 that is closer to the regenerator 12 than the heat exchange section 15. The heated fluid Lh that has flowed into this heat exchange section 15 heats the heat exchange section 15 as it passes through the heat exchange section 15, and is discharged to the lean liquid supply pipe 31 that is closer to the absorber 11 than the heat exchange section 15. The heated fluid Lh that has been discharged to the lean liquid supply pipe 31 that is closer to the absorber 11 returns to the vessel 37 via the second return pipe 50 and the main return pipe 53.

[0047] (Transition State) When starting operation of the absorption tower 11 and the regeneration tower 12 from a state in which the absorption tower 11 and the regeneration tower 12 are stopped, the control device 18 of the present embodiment switches the carbon dioxide capture system 100 through a transition state and then to a second state. In the transition state, the supply of the heated fluid Lh to the heat exchanger 15 is continued while the circulation of the absorption solution between the absorption tower 11 and the regeneration tower 12 is started. This transition state continues until the warm-up operation of the absorption tower 11 and the regeneration tower 12 is completed and the temperature of the absorption solution sent from the regeneration tower 12 to the absorption tower 11 has risen sufficiently (transition process). Here, whether the temperature of the absorption solution has risen sufficiently can be determined, for example, by estimating the time elapsed since the start of operation or by measuring the temperature of the absorption solution.

[0048] 6 , when switching from the first state to the transition state, the control device 18 maintains the first valve 28, the second valve 29, the third valve 33, and the fourth valve 34 in a closed state, and maintains the fifth valve 47, the sixth valve 48, the seventh valve 51, and the eighth valve 52 in an open state. The control device 18 also opens the ninth valve 57 and the tenth valve 58, which were previously closed. After switching to this transition state, operation of the first pump 27, the second pump 32, etc. is started, and operation of the absorber 11 and the regenerator 12 is started. Note that the operation and stopping of the first pump 27, the second pump 32, etc. can be performed, for example, by an operator, but may also be automatically controlled by the control device 18, etc.

[0049] In this transition state, the absorbing liquid circulating between the absorber 11 and the regenerator 12 flows bypassing the heat exchange unit 15. Specifically, the absorbing liquid in the absorber 11 is introduced into the rich liquid supply pipe 26 of the rich liquid line 13. The absorbing liquid introduced into the rich liquid supply pipe 26 flows into the first bypass pipe 55 without reaching the heat exchange unit 15. The absorbing liquid that flows into the first bypass pipe 55 is supplied to the regenerator 12 via the rich liquid supply pipe 26 between the heat exchange unit 15 and the regenerator 12. Meanwhile, the absorbing liquid in the regenerator 12 is introduced into the lean liquid supply pipe 31 of the lean liquid line 14. The absorbing liquid introduced into the lean liquid supply pipe 31 flows into the second bypass pipe 56 without reaching the heat exchange unit 15. The absorbing liquid that flows into the second bypass pipe 56 is supplied to the absorber 11 via the lean liquid supply pipe 31 between the heat exchange unit 15 and the absorber 11.

[0050] (Second State) When the warm-up operation of the absorption tower 11 and the regeneration tower 12 is completed, the control device 18 of this embodiment switches to the second state (steady operation) in order to start heat exchange by the heat exchange unit 15. That is, as shown in Fig. 7 , the control device 18 opens the first valve 28, the second valve 29, the third valve 33, and the fourth valve 34, and closes the fifth valve 47, the sixth valve 48, the seventh valve 51, the eighth valve 52, the ninth valve 57, and the tenth valve 58. The control device 18 also switches the heated fluid supply pump 44 from an operating state to a stopped state.

[0051] As a result, the heated fluid Lh stops circulating through the circulation line 39 and becomes stored in the vessel 37. The absorption liquid that has absorbed carbon dioxide in the absorption tower 11 reaches the heat exchange unit 15 as rich liquid R through the rich liquid supply pipe 26, exchanges heat with the lean liquid Le in the heat exchange unit 15, and is then supplied to the regeneration tower 12. The absorption liquid that has released carbon dioxide in the regeneration tower 12 reaches the heat exchange unit 15 as lean liquid Le through the lean liquid supply pipe 31, exchanges heat with the rich liquid R in the heat exchange unit 15, and is then supplied to the absorption tower 11.

[0052] (Effects) The carbon dioxide capture system 100 of the above embodiment includes an absorption tower 11 that brings exhaust gas G containing carbon dioxide into contact with an absorption liquid capable of absorbing carbon dioxide to produce a rich liquid R that has absorbed the carbon dioxide from the exhaust gas G, a regeneration tower that heats the rich liquid R to release carbon dioxide from the rich liquid R and produce a lean liquid Le from which the carbon dioxide has been released, a rich liquid line 13 that guides the rich liquid R from the absorption tower 11 to the regeneration tower 12, a lean liquid line 14 that guides the lean liquid Le from the regeneration tower 12 to the absorption tower 11, a heat exchange unit 15 that exchanges heat between the lean liquid Le flowing through the lean liquid line 14 and the rich liquid R, and a heating fluid supply unit 16 that can supply a heating fluid Lh that warms the heat exchange unit 15 to the heat exchange unit 15. As a result, even when the recovery of carbon dioxide by the absorption tower 11 and the regeneration tower 12 is stopped, the heat exchange unit 15 can be heated by the heating fluid Lh. Therefore, even if the carbon dioxide capture system 100 is repeatedly started and stopped, the heat exchange unit 15 does not alternate between high-temperature and low-temperature states. This reduces the burden on components such as the gaskets of the heat exchange unit 15, and prevents unexpected damage to the components.

[0053] The heating fluid supply unit 16 of the above embodiment includes a vessel 37 that stores the heating fluid Lh, a heating unit 38 that heats the heating fluid Lh, and a circulation line 39 that supplies the heating fluid Lh stored in the vessel 37 to the heat exchange unit 15 and returns the heating fluid Lh supplied to the heat exchange unit 15 to the vessel 37. As a result, the heating fluid Lh stored in the vessel 37 can be heated by the heating unit 38, and the heating fluid Lh heated in the vessel 37 can be supplied to the heat exchange unit 15 to heat the heat exchange unit 15. After heating the heat exchange unit 15, the heating fluid Lh can be returned to the vessel 37 and heated again. Therefore, the heating fluid Lh can be efficiently heated, and heating of the heat exchange unit 15 can be easily continued.

[0054] The carbon dioxide capture system 100 of the above embodiment further includes heat exchanger bypass lines 17A, 17B that divert the absorbing liquid so as to prevent the absorbing liquid from flowing into the heat exchanger 15. Therefore, while the absorption tower 11 and the regeneration tower 12 are operating, it is possible to prevent low-temperature absorbing liquid immediately after the start of operation from flowing into the heat exchanger 15, thereby further suppressing a decrease in the temperature of the heat exchanger 15.

[0055] The carbon dioxide capture system 100 of the above embodiment includes a plurality of control valves that can be switched between a first state and a second state, namely, a first valve 28, a second valve 29, a third valve 33, a fourth valve 34, a fifth valve 47, a sixth valve 48, a seventh valve 51, an eighth valve 52, a ninth valve 57, and a tenth valve 58, and the operation of these plurality of control valves is controlled by a control device 18. This makes it possible to automatically switch between the first state and the second state. As a result, it is possible to reduce the burden on the worker compared to when the valves are switched manually.

[0056] Second Embodiment Next, a second embodiment of the present disclosure will be described with reference to the drawings. A carbon dioxide capture system 200 of this second embodiment differs from the carbon dioxide capture system 100 of the first embodiment described above only in the configuration for heating the heat exchange unit. Therefore, with reference to Figures 2 and 4, the same parts as those of the first embodiment described above will be assigned the same reference numerals and redundant description will be omitted.

[0057] FIG. 8 is a diagram showing a schematic configuration of a carbon dioxide capture system according to a second embodiment of the present disclosure.

[0058] As shown in Figure 8, the carbon dioxide recovery system 200 according to the second embodiment includes an absorption tower 11, a regeneration tower 112, a rich liquid line 113, a lean liquid line 114, a plurality of heat exchange units 115A, 115B, a heated fluid supply unit 116, a first connection line 81, a first flow rate adjustment unit 83, a second flow rate adjustment unit 84, and a control device 118.

[0059] The absorption tower 11 has the same configuration as the absorption tower 11 of the first embodiment described above, and by bringing exhaust gas G containing carbon dioxide into contact with an absorption liquid capable of absorbing carbon dioxide, a rich liquid R is produced, which is an absorption liquid that has absorbed the carbon dioxide from the exhaust gas G.

[0060] The regeneration tower 112 heats the rich liquid R to release carbon dioxide from the rich liquid R, thereby generating a lean liquid Le, which is an absorption liquid from which carbon dioxide has been released. The regeneration tower 112 of the second embodiment is further configured to store the absorption liquid as a heated fluid in the lower part when the lean liquid Le is not being generated. The regeneration tower 112 of the second embodiment is provided with a regeneration tower circulation pipe 85 in the vertical direction, which is its length direction, that sends the absorption liquid to the outside of the regeneration tower 112 and then returns it.

[0061] The rich liquid line 113 guides the rich liquid R from the absorption tower 11 to the regeneration tower 112. The rich liquid line 113 includes a tubular rich liquid supply pipe 126 that forms a flow path for the rich liquid R, a first pump 127 for sending the rich liquid R to the regeneration tower 112, and a first valve 128 that opens and closes the flow path in the rich liquid supply pipe 126.

[0062] The lean liquid line 114 guides the lean liquid Le from the regeneration tower 112 to the absorption tower 11. The lean liquid line 114 of the second embodiment includes a tubular lean liquid supply pipe 131 that forms a flow path through which the lean liquid Le flows, a second pump 132 that sends the lean liquid Le to the absorption tower 11, and a third valve 133 that opens and closes the flow path in the lean liquid supply pipe 131.

[0063] The heat exchanger 115A and the heat exchanger 115B exchange heat between the lean liquid Le flowing through the lean liquid line 114 and the absorbing liquid having a different temperature from the lean liquid Le flowing through the lean liquid line 114. The heat exchanger 115A is connected to both the rich liquid supply pipe 126 and the lean liquid supply pipe 131. Similar to the heat exchanger 15 of the first embodiment, the heat exchanger 115A is capable of exchanging heat between the rich liquid R flowing through the rich liquid supply pipe 126 of the rich liquid line 113 and the lean liquid Le flowing through the lean liquid supply pipe 131 of the lean liquid line 114.

[0064] The heat exchanger 115B is connected to both the regenerator circulation pipe 85 and the lean liquid supply pipe 131. Specifically, the heat exchanger 115B is disposed midway through the regenerator circulation pipe 85 and midway through the lean liquid supply pipe 131 between the heat exchanger 115A and the regenerator 112. The heat exchanger 115B is capable of exchanging heat between the absorption liquid flowing in the regenerator circulation pipe 85 and the lean liquid Le flowing in the lean liquid supply pipe 131 of the lean liquid line 114. Here, when the carbon dioxide capture system 200 is capturing carbon dioxide from the flue gas G, the temperature of the absorption liquid flowing in the regenerator circulation pipe 85 is lower than the temperature of the lean liquid Le delivered from the bottom of the regenerator 112. In other words, the heat exchanger 115B uses the heat of the lean liquid Le to heat the absorption liquid flowing in the regenerator circulation pipe 85.

[0065] The heated fluid supply unit 116 is capable of supplying heated fluid Lh to the heat exchange units 115A and 115B. The heated fluid supply unit 116 of this second embodiment includes the regenerator 112, the heating unit 138, and the first connection line 81. The heated fluid supply unit 116 exemplified in this second embodiment further includes a heated fluid delivery line 86.

[0066] The regenerator 112 constituting the heated fluid supply unit 116 is the regenerator 112 when the carbon dioxide capture system 200 is not capturing carbon dioxide from the flue gas G (hereinafter simply referred to as "stopped"). In other words, the heated fluid supply unit 116 uses the absorption liquid stored in the lower part of the regenerator 112 as the heated fluid Lh when the lean liquid Le is not being produced.

[0067] The heating unit 138 heats the heating fluid Lh. The heating unit 138 of the second embodiment is attached to the regenerator 112 and is capable of heating the heating fluid Lh stored in the lower part of the regenerator 112 to a predetermined temperature (e.g., 30°C or higher) when the regenerator 112 is stopped. Note that if the steam heating system 22 is available when the regenerator 112 is stopped, the steam heating system 22 may be used instead of the heating unit 138.

[0068] The heated fluid delivery line 86 bypasses the second pump 132 and delivers heated fluid Lh from the regenerator 112 to the lean liquid line 114 when the regenerator 112 is stopped. The heated fluid delivery line 86 includes a heated fluid delivery pipe 87 and a heated fluid supply pump 144. The heated fluid delivery pipe 87 branches off from the lean liquid supply pipe 131 between the second pump 132 and the regenerator 112 and is connected to merge with the lean liquid supply pipe 131 between the eleventh valve 89 and the heat exchanger 115B. The heated fluid supply pump 144 has an output suitable for circulating the heated fluid Lh to the heat exchangers 115A and 115B. The output of the heated fluid supply pump 144 is, for example, smaller than the output of the second pump 132. Note that if the flow rate of the second pump 132 is variable, the heated fluid delivery line 86 may be omitted.

[0069] The first connection line 81 is configured to be able to communicate between the lean liquid line 114, which is closer to the absorber 11 than the heat exchange units 115A and 115B, and the rich liquid line 113. The first connection line 81 includes a first connection pipe 91 and a first connection valve 92. The first connection pipe 91 branches off from the lean liquid supply pipe 131 and is connected to merge with the rich liquid supply pipe 126. In other words, the first connection pipe 91 forms a flow path that allows the absorption liquid flowing through the lean liquid supply pipe 131 to flow into the rich liquid supply pipe 126. The first connection valve 92 opens and closes the flow path in the first connection pipe 91.

[0070] The second connection line 82 is configured to be able to communicate between the rich liquid line 113, which is closer to the absorber 11 than the first connection line 81, and the lean liquid line 114, which is closer to the absorber 11 than the first connection line 81. Specifically, the second connection line 82 is configured to be able to communicate between the rich liquid supply pipe 126 between the first pump 127 and the first valve 128, and the lean liquid supply pipe 131 between the third valve 133 and the cooling device 35. The second connection line 82 includes a second connection pipe 93 and a second connection valve 94. The second connection pipe 93 branches off from the rich liquid supply pipe 126 and is connected to merge with the lean liquid supply pipe 131. In other words, the second connection pipe 93 forms a flow path that allows the absorption liquid flowing through the rich liquid supply pipe 126 to flow into the lean liquid supply pipe 131. The second connection valve 94 opens and closes the flow path in the second connection pipe 93.

[0071] The first flow rate adjustment unit 83 is connected to the rich solution supply pipe 126 between the first connection line 81 and the second connection line 82. The first flow rate adjustment unit 83 is provided in parallel with the first valve 128. The first flow rate adjustment unit 83 includes a first flow rate adjustment pipe 95 and a first flow rate adjustment valve 96. The first flow rate adjustment pipe 95 forms a flow path that bypasses the first valve 128. The first flow rate adjustment valve 96 is capable of gradually increasing its opening degree from at least a closed state. In other words, the first flow rate adjustment unit 83 is capable of gradually increasing the flow rate of the absorption solution flowing through the rich solution supply pipe 126 between the first connection line 81 and the second connection line 82 when the first valve 128 is closed.

[0072] The second flow rate adjustment unit 84 is connected to the lean liquid supply pipe 131 between the first connection line 81 and the second connection line 82. The second flow rate adjustment unit 84 is provided in parallel with the third valve 133. The second flow rate adjustment unit 84 includes a second flow rate adjustment pipe 97 and a second flow rate adjustment valve 98. The second flow rate adjustment pipe 97 forms a flow path that bypasses the third valve 133. The second flow rate adjustment valve 98 is capable of gradually increasing its opening degree from at least a closed state. In other words, the second flow rate adjustment unit 84 is capable of gradually increasing the flow rate of the absorbing liquid flowing through the lean liquid supply pipe 131 between the first connection line 81 and the second connection line 82 when the third valve 133 is closed.

[0073] The control device 118 is capable of controlling the operation of a plurality of control valves, namely, a first valve 128, a third valve 133, an eleventh valve 89, a first connection valve 92, a second connection valve 94, a first flow rate adjustment valve 96, and a second flow rate adjustment valve 98. The control device 118 is also capable of switching between operating and stopping a heated fluid supply pump 144. The control device 118 is also capable of controlling the operation of a heating unit 138. As shown in FIG. 2 , the control device 118 of the second embodiment is also a computer including a CPU 61 (Central Processing Unit), a ROM 62 (Read Only Memory), a RAM 63 (Random Access Memory), a storage 64, and a signal transmission / reception module 65.

[0074] 9 is a functional block diagram of a control device according to a second embodiment of the present disclosure. As shown in Fig. 9, a CPU 61 of the control device 18 executes a program stored in advance in a storage device such as a ROM 62 or a storage 64, thereby realizing the respective functional components of a signal input unit 70, a valve control unit 171, a pump control unit 172, an output unit 73, and a heating control unit 99.

[0075] The signal input unit 70 receives information relating to the operating status of the carbon dioxide capture system 200 via the signal transmission / reception module 65, which is hardware. The valve control unit 171 generates control signals for controlling the operations of the first valve 128, the third valve 133, the eleventh valve 89, the first connection valve 92, the second connection valve 94, the first flow rate adjustment valve 96, and the second flow rate adjustment valve 98, based on the information relating to the operating status of the carbon dioxide capture system 200 received by the signal input unit 70.

[0076] The pump control unit 172 generates a control signal for controlling the operation of the heated fluid supply pump 144, based on information regarding the operating status of the carbon dioxide capture system 200 received by the signal input unit 70. The output unit 73 outputs the control signals generated by the valve control unit 171 and the pump control unit 172 to the first valve 128, the third valve 133, the eleventh valve 89, the first connection valve 92, the second connection valve 94, the first flow rate adjustment valve 96, the second flow rate adjustment valve 98, and the heated fluid supply pump 144, respectively, via the signal transmitting / receiving module 65.

[0077] The valve control unit 171 and the pump control unit 172 of the control device 118 are capable of switching between a first state in which the heating fluid Lh is supplied to the heat exchange units 115A and 115B to heat the heat exchange units 115A and 115B based on information regarding the operating status of the carbon dioxide capture system 200, and a second state in which the rich liquid R produced by the absorption tower 11 and the lean liquid Le produced by the regeneration tower 112 are each supplied to the heat exchange unit 115A for heat exchange. In the second state of the second embodiment, the absorption liquid flowing through the regeneration tower circulation piping 85 and the lean liquid Le are each supplied to the heat exchange unit 115B for heat exchange. Note that switching between the first state and the second state in the second embodiment may be performed based on an operator's operational input. The valve control unit 171 and the pump control unit 172 of the second embodiment further control a transition state between the first state and the second state. In this transition state, the control device 118 performs control to start recovering carbon dioxide from the exhaust gas G while continuing to supply the heated fluid Lh to the heat exchange sections 115A and 115B.

[0078] (Method of operating a carbon dioxide capture system) Fig. 10 is a diagram showing a first state of a carbon dioxide capture system according to a second embodiment of the present disclosure. Fig. 11 is a diagram showing a transition state of a carbon dioxide capture system according to a second embodiment of the present disclosure. Fig. 12 is a diagram showing a second state of a carbon dioxide capture system according to a second embodiment of the present disclosure.

[0079] 4 , the operating method of the carbon dioxide capture system of this embodiment includes a heating step S11 and a transition step S12. In the heating step S11, when the absorber 11 and the regenerator 112 are stopped, a heating fluid Lh is supplied to the heat exchange units 115A and 115B to set the first state in which the heat exchange units 115A and 115B are heated. In the transition step S12, when starting operation of the absorber 11 and the regenerator 112 from the first state, the operation of the absorber 11 is started and the absorbing liquid Lh that has flowed from the absorber 11 into the rich liquid line 113 is circulated back to the absorber 11 via the second connection line 82 and the lean liquid line 114 while continuing to heat the heat exchange units 115A and 115B with the heating fluid Lh. In the transition state of this second embodiment, the heated fluid Lh circulating through the regeneration tower 112, the lean liquid line 114, the first connection line 81 and the rich liquid line 113 is further mixed with the absorption liquid circulating through the absorption tower 11, the rich liquid line 113, the second connection line 82 and the lean liquid line 114 by the first flow rate control unit 83 and the second flow rate control unit 84, thereby gradually reducing the temperature difference between the absorption liquid and the heated fluid Lh.

[0080] (First State) When the exhaust gas G is not introduced into the absorption tower 11 and the absorption tower 11 and the regeneration tower 112 are not operating, the control device 118 closes the first valve 128, the third valve 133, the eleventh valve 89, the first flow control valve 96, and the second flow control valve 98 and opens the first connection valve 92, as shown in Fig. 10 , in order to set the carbon dioxide capture system 200 to the first state. To set the system to the first state, the control device 118 operates the heated fluid supply pump 144 and the heating unit 138 (heating step S11). Here, the second connection valve 94 may be open.

[0081] As a result, the absorption liquid stored in the regenerator 112 is heated to become a heated fluid Lh. The heated fluid Lh is sent out from the regenerator 112 via the heated fluid delivery line 86, flows into the lean liquid supply pipe 131, and passes through the heat exchanger 115B and the heat exchanger 115A in this order. The heat exchanger 115B and the heat exchanger 115A are heated by the heat of the heated fluid Lh passing through them.

[0082] The heated fluid Lh that has passed through the heat exchange section 115A flows from the lean liquid supply pipe 131 into the first connection pipe 91 of the first connection line 81. The heated fluid Lh that has flowed into the first connection pipe 91 flows into the rich liquid supply pipe 126 and passes through the heat exchange section 115A. As the heated fluid Lh passes through the heat exchange section 115A, it again heats the heat exchange section 115A. The heated fluid Lh then reaches the upper part of the regenerator 112 via the rich liquid supply pipe 126 and flows into the regenerator circulation pipe 85 from the middle part of the regenerator 112. The heated fluid Lh that has flowed into the regenerator circulation pipe 85 passes through the heat exchange section 115B. As the heated fluid Lh passes through the heat exchange section 115B, it again heats the heat exchange section 115B. The heated fluid Lh that has flowed through the regenerator circulation pipe 85 is returned to the regenerator 112, stored in the lower part of the regenerator 112, and heated again by the heating unit 138. The heated heated fluid Lh repeats the above-mentioned series of circulations.

[0083] (Transition State) When starting circulation of the absorption solution between the absorption tower 11 and the regeneration tower 112 while carbon dioxide capture of the flue gas G by the absorption tower 11 and the regeneration tower 112 is stopped, the control device 118 of the second embodiment switches the carbon dioxide capture system 200 through a transition state and then to a second state. In the transition state, the control device 118 circulates the absorption solution closer to the absorber 11 than the first valve 128 and the third valve 133 via the second connection line 82, and circulates the absorption solution closer to the regeneration tower 112 than the first valve 128 and the third valve 133 via the first connection line 81. In the transition state, the control device 118 further gradually reduces the temperature difference between the absorption solution circulating on the side closer to the absorber 11 than the first valve 128 and the third valve 133 and the absorption solution circulating on the side closer to the regeneration tower 112 than the first valve 128 and the third valve 133 (transition step S12). Here, in the transition state of this embodiment, the absorption liquid closer to the regeneration tower 112 than the first valve 128 and the third valve 133 is heated using the circulation pipe 24 and the reboiler 23. Note that the heating unit 138 may automatically stop heating the absorption liquid when the absorption liquid reaches a predetermined temperature.

[0084] 11 , in the transition state, immediately before starting carbon dioxide recovery, the control device 118 opens the second connection valve 94 and the eleventh valve 89 and stops the heating unit 138 and the heated fluid supply pump 144. After that, when the first pump 127, the second pump 132, and the steam heating system 22 are started, the control device 118 gradually opens the first flow control valve 96 and the second flow control valve 98 while keeping the first valve 128 and the third valve 133 closed. In other words, the apertures of the first flow control valve 96 and the second flow control valve 98 are adjusted so that the flow rate of the rich liquid R flowing toward the regenerator 112 via the first flow control valve 96 gradually increases, and the flow rate of the lean liquid Le flowing toward the absorber 11 via the second flow control valve 98 gradually increases.

[0085] (Second State) When the first flow control valve 96 and the second flow control valve 98 are opened to their predetermined maximum opening degrees in the transition state, the control device 118 puts the carbon dioxide capture system 200 into the second state. As shown in Fig. 12 , the control device 118 puts the first valve 128, the third valve 133, and the eleventh valve 89 into an open state, and puts the first connection valve 92 and the second connection valve 94 into a closed state. The control device 118 also keeps the heated fluid supply pump 144 stopped.

[0086] As a result, the absorption liquid that has absorbed carbon dioxide in the absorption tower 11 reaches the heat exchange section 115A as rich liquid R through the rich liquid supply pipe 126, exchanges heat with lean liquid Le in the heat exchange section 115A, and is then supplied to the regeneration tower 12. The absorption liquid that is rich liquid R supplied to the regeneration tower 12 flows into the regeneration tower circulation pipe 85 and reaches the heat exchange section 115B while moving from the top to the bottom of the regeneration tower 12 while releasing carbon dioxide. The absorption liquid that has reached the heat exchange section 115B is heated by heat exchange with the lean liquid Le flowing through the lean liquid supply pipe 131, and is then returned to the regeneration tower 112 by the regeneration tower circulation pipe 85. The absorption liquid returned to the regeneration tower 112 is heated by the steam heating system 22 and releases carbon dioxide. The absorption liquid that has released carbon dioxide in the regeneration tower 12 is supplied to the absorption tower 11 as lean liquid Le after heat exchange with absorption liquids having a lower temperature than the lean liquid Le in the heat exchange sections 115B and 115A via the lean liquid supply pipe 131.

[0087] (Effects) The heating fluid supply unit 116 of the carbon dioxide capture system 200 according to the second embodiment includes a regenerator 112 capable of storing an absorption liquid as a heating fluid Lh in a lower portion thereof, a heating unit 138 that heats the absorption liquid as the heating fluid Lh stored in the lower portion of the regenerator 112, and a first connection line 81 that can communicate the lean liquid line 114, which is closer to the absorption tower 11 than the heat exchange unit 115A, with the rich liquid line 113. As a result, when carbon dioxide is not being captured from the flue gas G, the absorption liquid stored in the lower portion of the regenerator 112 can be heated and circulated to the heat exchange unit 115A as the heating fluid Lh. Therefore, the heat exchange units 115A and 115B can be heated when carbon dioxide is not being captured from the flue gas G, and the number of parts can be reduced compared to the carbon dioxide capture system 100 according to the first embodiment.

[0088] The second embodiment further includes a second connection line 82 that can connect the rich liquid line 113, which is closer to the absorber 11 than the first connection line 81, to a lean liquid line 114, which is closer to the absorber 11 than the first connection line 81, a first flow rate adjustment unit 83 that can gradually increase the flow rate of the absorbing liquid flowing through the rich liquid line 113 between the first connection line 81 and the second connection line 82, and a second flow rate adjustment unit 84 that can gradually increase the flow rate of the absorbing liquid flowing through the lean liquid line 114 between the first connection line 81 and the second connection line 82. With this configuration, the absorbing liquid that has flowed into the rich liquid line 113 from the absorber 11 can be returned to the absorber 11 by flowing into the lean liquid line 114 via the second connection line 82. This prevents cold absorbing liquid from flowing from the absorber 11 into the heat exchange units 115A, 115B immediately after the absorber 11 is started. Furthermore, the absorption liquid circulated through the second connection line 82 can be sent little by little to the heat exchanger 115A by the first flow rate adjuster 83, thereby suppressing sudden temperature changes in the absorption liquid flowing into the heat exchangers 115A and 115B. Similarly, the second flow rate adjuster 84 allows the absorption liquid heated by the regenerator 112 to be merged little by little with the absorption liquid closer to the absorber 11, thereby increasing the temperature. Therefore, a decrease in the temperature of the heat exchangers 115A and 115B can be suppressed, reducing the burden on the components of the heat exchangers 115A and 115B and suppressing unexpected damage to the components.

[0089] (Other Embodiments) The present disclosure is not limited to the configurations of the above-described embodiments, and design modifications are possible without departing from the spirit of the present disclosure. For example, in the above-described embodiments, the carbon dioxide capture systems 100 and 200 have been described as capturing carbon dioxide from flue gas G. However, the gas from which carbon dioxide is captured is not limited to flue gas G, as long as it contains carbon dioxide.

[0090] In each of the above-described embodiments, a transition state is interposed between the first state and the second state, but the transition state may be omitted as necessary. In each of the embodiments, a case where a plurality of control valves are opened and closed by the control device 18, 118 is described. However, the opening and closing operations of the valves are not limited to those controlled by the control device 18, 118. The valves may be opened and closed by an operator.

[0091] In the second embodiment described above, the case where the heat exchanger 115B is heated in addition to the heat exchanger 115A has been described. However, it is also possible to heat only the heat exchanger 115A or only the heat exchanger 115B. Furthermore, in the second embodiment, the case where only one pair of the regenerator circulation piping 85 and the heat exchanger 115B is provided has been described, but this configuration is not limited to this. For example, it is also possible to provide multiple pairs of the regenerator circulation piping 85 and the heat exchanger 115B. Furthermore, the heat exchanger 115B may be provided as needed, or may be omitted.

[0092] <Additional Notes> The carbon dioxide capture system described in the embodiment can be understood, for example, as follows.

[0093] (1) According to a first aspect, the carbon dioxide recovery system 100, 200 includes an absorption tower 11 that brings a carbon dioxide-containing gas G containing carbon dioxide into contact with an absorption liquid capable of absorbing the carbon dioxide to produce a rich liquid R that is the absorption liquid that has absorbed the carbon dioxide from the carbon dioxide-containing gas G; a regeneration tower 12, 112 that heats the rich liquid R to release the carbon dioxide from the rich liquid R and produces a lean liquid Le that is the absorption liquid from which the carbon dioxide has been released; and a regeneration tower 12, 112 that transfers the rich liquid Le from the absorption tower 11 to the regeneration tower 12, 112. The absorption tower 11 includes a rich liquid line 13, 113 for introducing a rich liquid R, a lean liquid line 14, 114 for introducing the lean liquid Le from the regeneration tower 12, 112 to the absorption tower 11, a heat exchange unit 15, 115A, 115B for heat exchange between the lean liquid Le flowing through the lean liquid line 14, 114 and the absorbing liquid having a different temperature from the lean liquid flowing through the lean liquid line 14, 114, and a heated fluid supply unit 16, 116 for supplying a heated fluid Lh for heating the heat exchange unit 15, 115A, 115B to the heat exchange unit 15, 115A, 115B. An example of a carbon dioxide-containing gas is exhaust gas. An example of an absorbing liquid is MEA. This reduces the burden on components such as gaskets of the heat exchange unit 15, 115A, 115B, thereby preventing unexpected damage to the components.

[0094] (2) According to a second aspect, the carbon dioxide capture system 100 is the carbon dioxide capture system 100 of (1), wherein the heating fluid supply unit 16 includes a vessel 37 that stores the heating fluid Lh, a heating unit 38 that heats the heating fluid Lh, and a circulation line 39 that supplies the heating fluid Lh stored in the vessel 37 to the heat exchange unit 15 and returns the heating fluid Lh that has been supplied to the heat exchange unit 15 to the vessel 37. This makes it possible to efficiently heat the heating fluid Lh and easily continue heating the heat exchange unit 15.

[0095] (3) According to a third aspect, the carbon dioxide capture system 100 is the carbon dioxide capture system 100 of (2), further including heat exchanger bypass lines 17A, 17B that bypass the absorption liquid so as to prevent the absorption liquid from flowing into the heat exchanger 15. This makes it possible to operate the absorption tower 11 and the regeneration tower 12 while preventing low-temperature absorption liquid immediately after the start of operation from flowing into the heat exchanger 15, thereby further suppressing a decrease in the temperature of the heat exchanger 15.

[0096] (4) According to a fourth aspect, the carbon dioxide capture system 100 is the carbon dioxide capture system 100 of (2), further including a plurality of control valves 28, 29, 33, 34, 47, 48, 51, 52, 57, and 58 that are switchable between a first state in which the heating fluid Lh is supplied to the heat exchange unit 15 to heat the heat exchange unit 15 and a second state in which the absorption liquid is supplied to the heat exchange unit 15 to perform heat exchange, and a control device 18 that controls the operation of the plurality of control valves 28, 29, 33, 34, 47, 48, 51, 52, 57, and 58. This makes it possible to automatically switch between the first state and the second state. As a result, it is possible to reduce the burden on the operator compared to when the valves are manually switched.

[0097] (5) According to a fifth aspect, the carbon dioxide capture system 200 is the carbon dioxide capture system 200 of (1), wherein the heating fluid supply unit 116 includes the regeneration tower 112 capable of storing the absorption liquid as the heating fluid Lh in a lower portion thereof, a heating unit 138 that heats the absorption liquid as the heating fluid Lh stored in the lower portion of the regeneration tower 112, and a first connection line 81 that can communicate the lean liquid line 114 that is closer to the absorption tower 11 than the heat exchange units 115A and 115B with the rich liquid line 113. This makes it possible to heat the heat exchange units 115A and 115B when carbon dioxide is not being captured from the exhaust gas G, and also reduces the number of parts.

[0098] (6) According to a sixth aspect, the carbon dioxide capture system 200 is the carbon dioxide capture system 200 of (5), further comprising: a second connection line 82 capable of connecting the rich liquid line 113, which is closer to the absorber 11 than the first connection line 81, to the lean liquid line 114, which is closer to the absorber 11 than the first connection line 81; a first flow rate adjustment unit 83 capable of gradually increasing the flow rate of the absorbing liquid flowing through the rich liquid line 113 between the first connection line 81 and the second connection line 82; and a second flow rate adjustment unit 84 capable of gradually increasing the flow rate of the absorbing liquid flowing through the lean liquid line 114 between the first connection line 81 and the second connection line 82. This allows the low-temperature absorbing liquid circulated through the second connection line 82 to be sent little by little to the heat exchange unit 115A by the first flow rate adjustment unit 83. Furthermore, the absorbing liquid heated by the regeneration tower 112 can be gradually merged with the absorbing liquid closer to the absorber 11 to increase its temperature. Therefore, it is possible to suppress a decrease in the temperature of the heat exchange sections 115A and 115B, reduce the load on the components of the heat exchange sections 115A and 115B, and prevent unexpected damage to the components.

[0099] (7) According to a seventh aspect, the carbon dioxide recovery system 200 is the carbon dioxide recovery system 200 of (6), and is provided with the rich liquid line 113, the lean liquid line 114, the first connection line 81, and the second connection line 82, and is configured to: a first state in which the absorbing liquid of the regenerator 112 is flowed as the heating fluid Lh from the lean liquid line 114 through the first connection line 81 into the rich liquid line 113 and returned to the regenerator 112; and a second state in which the rich liquid R is supplied from the absorption tower 11 to the regeneration tower 112 via the rich liquid line 113 and the lean liquid Le is supplied from the regeneration tower 112 to the absorption tower 11 via the lean liquid line 114, and a control device 118 that controls the control valves 89, 92, 94, 128, 133, the first flow rate adjustment unit 83, and the second flow rate adjustment unit 84. This makes it possible to automatically switch between the first state and the second state in the carbon dioxide capture system 200. As a result, it is possible to reduce the burden on operators compared to when valves are manually switched.

[0100] (8) According to an eighth aspect, a method of operating a carbon dioxide recovery system includes an absorption tower 11 that brings a carbon dioxide-containing gas containing carbon dioxide into contact with an absorption liquid capable of absorbing the carbon dioxide to produce a rich liquid R that is the absorption liquid that has absorbed the carbon dioxide from the carbon dioxide-containing gas; a regeneration tower 12, 112 that heats the rich liquid R to release the carbon dioxide from the rich liquid R and produce a lean liquid Le that is the absorption liquid from which the carbon dioxide has been released; a rich liquid line 13, 113 that guides the rich liquid R from the absorption tower 11 to the regeneration tower 12, 112; and a lean liquid line 14, 114 that guides the lean liquid Le from the regeneration tower 12, 112 to the absorption tower 11. An operating method for a carbon dioxide recovery system (100, 200) including a heat exchange unit (15, 115A, 115B) that exchanges heat between the lean liquid (Le) flowing through the lean liquid line (14, 114) and the absorbing liquid having a different temperature from the lean liquid (Le) flowing through the lean liquid line (14, 114), and a heating fluid supply unit (16, 116) that can supply a heating fluid (Lh) that heats the heat exchange unit (15, 115A, 115B) to the heat exchange unit (15, 115A, 115B), the operating method including a heating step (S01, S11) of supplying the heating fluid (Lh) to the heat exchange unit (15, 115A, 115B) to heat the heat exchange unit (15, 115A, 115B) when the absorption tower (11) and the regeneration tower (12, 112) are stopped. This reduces the load on the components such as the gaskets of the heat exchange units 15, 115A, and 115B, and prevents unexpected damage to the components.

[0101] (9) According to a ninth aspect, the method for operating a carbon dioxide capture system is the method for operating a carbon dioxide capture system of (8), wherein the carbon dioxide capture system 100 further includes heat exchanger bypass lines 17A, 17B that bypass the absorption liquid so that the absorption liquid does not flow into the heat exchanger 15, and further includes a transition step S02 in which, when starting operation of the absorption tower 11 and the regeneration tower 12 from a state in which the absorption tower 11 and the regeneration tower 12 are stopped, the absorption liquid circulating between the absorption tower 11 and the regeneration tower 12 is caused to bypass the heat exchanger 15 while continuing to supply the heating fluid Lh to the heat exchanger 15. This makes it possible to prevent low-temperature absorption liquid from flowing into the heat exchanger 15 immediately after the start of operation while operating the absorption tower 11 and the regeneration tower 12, thereby further suppressing a decrease in the temperature of the heat exchanger 15.

[0102] (10) According to a tenth aspect, the method for operating the carbon dioxide recovery system is the method for operating the carbon dioxide recovery system 200 of (8) or (9), wherein the heated fluid supply unit 116 includes the regeneration tower 112 capable of storing the absorbing liquid as the heated fluid Lh in a lower portion thereof, a heating unit 138 that heats the absorbing liquid as the heated fluid Lh stored in the lower portion of the regeneration tower 112, and the lean heat exchanger 115A, 115B that is closer to the absorber 11 than the heat exchangers 115A, 115B. and a first connection line 81 that can communicate a liquid line 114 with the rich liquid line 113. In the heating step S11, the absorption liquid stored in the regeneration tower 112 is heated and passed through the heat exchange units 115A, 115B via the lean liquid line 114 as the heated fluid Lh, and the heated fluid Lh that has passed through the heat exchange units 115A, 115B is returned to the regeneration tower 112 via the first connection line 81 and the rich liquid line 113. This makes it possible to heat the heat exchange units 115A, 115B when carbon dioxide is not being recovered from the exhaust gas G, and also reduces the number of parts.

[0103] (11) According to an eleventh aspect, the method for operating a carbon dioxide capture system is the method for operating the carbon dioxide capture system 200 of (10), wherein the carbon dioxide capture system 200 further includes a second connection line 82 that can connect the rich liquid line 113, which is closer to the absorption tower 11 than the first connection line 81, to the lean liquid line 114, which is closer to the absorption tower 11 than the first connection line 81. When starting operation of the absorption tower 11 and the regeneration tower 112 from a state in which the absorption tower 11 and the regeneration tower 112 are stopped, the method further includes a transition step S12 in which, while continuing to heat the heat exchange sections 115A, 115B with the heating fluid Lh, the operation of the absorption tower 11 is started and the absorption liquid that has flowed from the absorption tower 11 into the rich liquid line 113 is circulated so as to return to the absorption tower 11 via the second connection line 82 and the lean liquid line 114. As a result, the low-temperature absorption liquid is not sent to the heat exchange section 115A immediately after the operation of the absorption tower 11 and the regeneration tower 112 is started, thereby suppressing the temperature drop of the heat exchange sections 115A and 115B, reducing the burden on the components of the heat exchange sections 115A and 115B, and preventing unexpected damage to the components.

[0104] (12) According to a twelfth aspect, a method for operating a carbon dioxide capture system is the method for operating the carbon dioxide capture system 200 of (11), in which the carbon dioxide capture system 200 includes a first flow rate adjustment unit 83 that can gradually increase a flow rate of the absorbing liquid flowing through the rich liquid line 113 between the first connecting line 81 and the second connecting line 82, and a second flow rate adjustment unit 84 that can gradually increase a flow rate of the absorbing liquid flowing through the lean liquid line 114 between the first connecting line 81 and the second connecting line 82. In the transition step S12, the heating fluid Lh circulating via the regeneration tower 112, the lean liquid line 114, the first connection line 81, and the rich liquid line 113 is gradually mixed with the absorbing liquid circulating via the absorption tower 11, the rich liquid line 113, the second connection line 82, and the lean liquid line 114 by the first flow rate adjustment unit 83 and the second flow rate adjustment unit 84, thereby gradually reducing the temperature difference between the absorbing liquid and the heating fluid Lh. This allows the low-temperature absorbing liquid circulating via the second connection line 82 to be sent little by little to the heat exchange unit 115A by the first flow rate adjustment unit 83. Furthermore, the absorbing liquid heated by the regeneration tower 112 can be gradually merged with the absorbing liquid closer to the absorption tower 11 to increase its temperature. Therefore, it is possible to suppress a decrease in the temperature of the heat exchange sections 115A and 115B, reduce the load on the components of the heat exchange sections 115A and 115B, and prevent unexpected damage to the components.

[0105] According to the carbon dioxide capture system according to the present disclosure, the burden on the components of the heat exchanger can be reduced.

[0106] 100, 200 Carbon dioxide recovery system 11 Absorption tower 12, 112 Regeneration tower 13, 113 Rich liquid line 14, 114 Lean liquid line 15, 115A, 115B Heat exchange section 16, 116 Heated fluid supply section 17A, 17B Heat exchange section bypass line 18, 118 Control device 20 Recovery section 21 Cleaning section 22 Steam heating system 23 Reboiler 24 Circulation piping 26, 126 Rich liquid supply piping 27, 127 First pump 28, 128 First valve 29 Second valve 31 Lean liquid supply piping 32, 132 Second pump 33, 133 Third valve 34 Fourth valve 35 Cooling device 37 Vessel 38, 138 Heating section 39 Circulation line 41 Heated fluid supply line 42 Heated fluid return line 43 Main supply pipe 44, 144 Heated fluid supply pump 45 First supply pipe 46 Second supply pipe 47 Fifth valve 48 Sixth valve 49 First return pipe 50 Second return pipe 51 Seventh valve 52 Eighth valve 53 Main return pipe 55 First bypass pipe 56 Second bypass pipe 57 Ninth valve 58 Tenth valve 61 CPU 62 ROM 63 RAM 64 Storage 65 Signal transmitting / receiving module 70 Signal input unit 71, 171 Valve control unit 72, 172 Pump control unit 73 Output unit 81 First connecting line 82 Second connecting line 83 First flow rate adjustment unit 84 Second flow rate adjustment unit 85 Regeneration tower circulation pipe 86 Heated fluid delivery line 87 Heated fluid delivery pipe 89 Eleventh valve 91 First connecting pipe 92 First connecting valve 93 Second connecting pipe 94 Second connecting valve 95 First flow rate adjustment pipe 96 First flow rate adjustment valve 97 Second flow rate adjustment pipe 98 Second flow rate adjustment valve 99 Heating control unit S01, S11 Heating process S02, S12 Transition process

Claims

1. an absorption tower that brings a carbon dioxide-containing gas containing carbon dioxide into contact with an absorption liquid capable of absorbing the carbon dioxide to produce a rich liquid that is the absorption liquid that has absorbed the carbon dioxide from the carbon dioxide-containing gas; a regeneration tower that heats the rich liquid to release the carbon dioxide from the rich liquid and generates a lean liquid, which is the absorption liquid from which the carbon dioxide has been released; a rich liquid line that guides the rich liquid from the absorption tower to the regeneration tower; a lean liquid line that guides the lean liquid from the regeneration tower to the absorption tower; a heat exchange unit that exchanges heat between the lean liquid flowing through the lean liquid line and the rich liquid flowing through the rich liquid line; a heating fluid supply unit capable of supplying a heating fluid for heating the heat exchange unit to the lean liquid line and the rich liquid line of the heat exchange unit; A carbon dioxide capture system comprising:

2. The heating fluid supply unit a vessel for storing the heating fluid; a heating unit that heats the heating fluid; a circulation line that supplies the heated fluid stored in the vessel to the heat exchange unit and returns the heated fluid supplied to the heat exchange unit to the vessel; Equipped with The carbon dioxide capture system of claim 1 .

3. The heat exchanger further includes a bypass line for bypassing the absorbing liquid so that the absorbing liquid does not flow into the heat exchanger. The carbon dioxide capture system of claim 2 .

4. a plurality of control valves that are switchable between a first state in which the heating fluid is supplied to the heat exchange unit to heat the heat exchange unit, and a second state in which the absorption liquid is supplied to the heat exchange unit to perform heat exchange; a control device for controlling the operation of the plurality of control valves; Further provided with The carbon dioxide capture system of claim 2 .

5. The heating fluid supply unit a regeneration tower capable of storing the absorption liquid as the heating fluid in a lower portion thereof; a heating unit that heats the absorption liquid as the heating fluid stored in the lower part of the regeneration tower; a first connection line that can connect the lean liquid line that is closer to the absorption tower than the heat exchange unit to the rich liquid line; Equipped with The carbon dioxide capture system of claim 1 .

6. a second connection line that can connect the rich liquid line, which is closer to the absorber than the first connection line, to the lean liquid line, which is closer to the absorber than the first connection line; a first flow rate adjusting unit capable of gradually increasing a flow rate of the absorbing liquid flowing through the rich liquid line between the first connecting line and the second connecting line; a second flow rate adjusting unit that gradually increases the flow rate of the absorbing liquid flowing through the lean liquid line between the first connecting line and the second connecting line; Further provided with The carbon dioxide capture system of claim 5 .

7. a plurality of control valves provided in the rich liquid line, the lean liquid line, the first connecting line, and the second connecting line, which are switchable between a first state in which the absorption liquid in the regeneration tower is returned to the regeneration tower as the heated fluid by flowing from the lean liquid line through the first connecting line into the rich liquid line, and a second state in which the rich liquid is supplied from the absorption tower to the regeneration tower through the rich liquid line, and the lean liquid is supplied from the regeneration tower to the absorption tower through the lean liquid line; a control device that controls the plurality of control valves, the first flow rate adjustment unit, and the second flow rate adjustment unit; Further provided with The carbon dioxide capture system of claim 6.

8. an absorption tower that brings a carbon dioxide-containing gas containing carbon dioxide into contact with an absorption liquid capable of absorbing the carbon dioxide to produce a rich liquid that is the absorption liquid that has absorbed the carbon dioxide from the carbon dioxide-containing gas; a regeneration tower that heats the rich liquid to release the carbon dioxide from the rich liquid and generates a lean liquid, which is the absorption liquid from which the carbon dioxide has been released; a rich liquid line that guides the rich liquid from the absorption tower to the regeneration tower; a lean liquid line that guides the lean liquid from the regeneration tower to the absorption tower; a heat exchange unit that exchanges heat between the lean liquid flowing through the lean liquid line and the rich liquid flowing through the rich liquid line; a heating fluid supply unit capable of supplying a heating fluid to the heat exchange unit; A method of operating a carbon dioxide capture system comprising: A heating step of supplying the heating fluid to the heat exchange section to heat the heat exchange section when the absorption tower and the regeneration tower are out of operation. How to operate a carbon dioxide capture system.

9. The carbon dioxide capture system comprises: a heat exchange unit bypass line that bypasses the absorption liquid so that the absorption liquid does not flow into the heat exchange unit; When starting operation of the absorption tower and the regeneration tower from a state in which the absorption tower and the regeneration tower are stopped, the method further includes a transition step of causing the absorption liquid circulating between the absorption tower and the regeneration tower to bypass the heat exchange unit while continuing to supply the heating fluid to the heat exchange unit. A method for operating a carbon dioxide capture system according to claim 8.

10. The heating fluid supply unit a regeneration tower capable of storing the absorption liquid as the heating fluid in a lower portion thereof; a heating unit that heats the absorption liquid as the heating fluid stored in the lower part of the regeneration tower; a first connection line that can connect the lean liquid line that is closer to the absorption tower than the heat exchange unit to the rich liquid line, In the heating step, The absorption liquid stored in the regeneration tower is heated and passed as the heated fluid through the heat exchange unit via the lean liquid line, and the heated fluid that has passed through the heat exchange unit is returned to the regeneration tower through the first connection line and the rich liquid line. A method for operating a carbon dioxide recovery system according to claim 8 or 9.

11. The carbon dioxide capture system comprises: a second connection line that can connect the rich liquid line, which is closer to the absorber than the first connection line, to the lean liquid line, which is closer to the absorber than the first connection line; When starting operation of the absorption tower and the regeneration tower from a state in which the absorption tower and the regeneration tower are stopped, the method further includes a transition step of starting operation of the absorption tower and circulating the absorption liquid that has flowed from the absorption tower into the rich liquid line to the absorption tower via the second connection line and the lean liquid line while continuing to heat the heat exchange section with the heating fluid. A method for operating a carbon dioxide capture system according to claim 10.

12. The carbon dioxide capture system comprises: a first flow rate adjusting unit capable of gradually increasing a flow rate of the absorbing liquid flowing through the rich liquid line between the first connecting line and the second connecting line; a second flow rate adjusting unit that gradually increases the flow rate of the absorbing liquid flowing through the lean liquid line between the first connecting line and the second connecting line; Further provided with In the transition step, The heated fluid circulating through the regeneration tower, the lean liquid line, the first connecting line, and the rich liquid line, and the absorbing liquid circulating through the absorption tower, the rich liquid line, the second connecting line, and the lean liquid line are gradually mixed by the first flow rate adjustment unit and the second flow rate adjustment unit, thereby gradually reducing the temperature difference between the absorbing liquid and the heated fluid. A method for operating a carbon dioxide capture system according to claim 11.