Carbon dioxide capture device, operation method of the carbon dioxide capture device

Abstract

This enhances the carbon dioxide absorption efficiency even when the gas supplied to the carbon dioxide capture device is at a low temperature. [Solution] The carbon dioxide recovery device comprises a gas introduction line into which gas containing carbon dioxide is supplied from the outside; a scrubbing tower that cleans the gas by bringing the gas supplied to the gas introduction line into contact with a cleaning solution; an absorption tower into which an absorbent liquid capable of absorbing carbon dioxide in the gas is introduced and absorbs the carbon dioxide in the gas that has passed through the gas scrubbing tower; a regeneration tower that heats the absorbent liquid that has absorbed carbon dioxide, separates the carbon dioxide from the absorbent liquid, and regenerates the absorbent liquid; and a heating unit that heats the gas supplied to the absorption tower.

Description

Technical Field

[0001] The present disclosure relates to a carbon dioxide recovery device and an operation method of the carbon dioxide recovery device.

Background Art

[0002] It is desired to reduce the amount of carbon dioxide emissions contained in gases from ships, steel mills, etc. For example, Patent Document 1 discloses a configuration including a carbon dioxide recovery device that recovers carbon dioxide contained in gases (exhaust gases) from ships.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the carbon dioxide recovery device as described above, the gas containing carbon dioxide that is sent from the internal combustion engine installed on a ship or the blast furnace of a steel mill, etc. to the carbon dioxide recovery device has a temperature range of 50 to 200°C, which is the general chimney outlet gas temperature, and the configuration of each part is designed.

[0005] However, in the case of ships navigating areas with low sea surface temperatures, such as the Arctic or Antarctic, or in steel mills located in regions where outside temperatures are below freezing, the temperature of the gas may be in the low-temperature range, such as below ambient temperature or below freezing in cold regions, by the time it is sent to the carbon dioxide recovery unit. For example, in a ship, if sulfur is removed from the gas in a desulfurization unit before it is sent to the carbon dioxide recovery unit, using cold seawater pumped from the surrounding sea for the desulfurization process will lower the temperature of the gas after desulfurization. Also, in steel mills, if the distance between the blast furnace and the carbon dioxide recovery unit is large, the temperature of the gas may decrease by the time it reaches the carbon dioxide recovery unit. When the gas temperature decreases in this way, the carbon dioxide absorption efficiency of the carbon dioxide recovery unit, when the absorbent liquid absorbs carbon dioxide, may decrease significantly.

[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a carbon dioxide capture device and a method for operating the carbon dioxide capture device that can increase the carbon dioxide absorption efficiency even when the gas supplied to the carbon dioxide capture device is at a low temperature. [Means for solving the problem]

[0007] To solve the above problems, the carbon dioxide recovery apparatus according to the present disclosure comprises: a gas introduction line into which a gas containing carbon dioxide is supplied from the outside; a washing tower that washes the gas by bringing the gas supplied to the gas introduction line into contact with a washing liquid; an absorption tower into which an absorbent liquid capable of absorbing carbon dioxide in the gas is introduced and the absorbent liquid absorbs the carbon dioxide in the gas that has passed through the gas washing tower; a regeneration tower that heats the absorbent liquid that has absorbed carbon dioxide, separates carbon dioxide from the absorbent liquid, and regenerates the absorbent liquid; and a heating unit that heats the gas supplied to the absorption tower.

[0008] The method for operating a carbon dioxide recovery apparatus according to this disclosure is a method for operating a carbon dioxide recovery apparatus as described above, comprising the steps of: detecting the inlet temperature of the gas supplied through the gas introduction line; and, if the inlet temperature of the gas is within a preset range, heating the gas supplied to the absorption tower in the heating unit. [Effects of the Invention]

[0009] According to the carbon dioxide capture device and the operating method of the carbon dioxide capture device described herein, the carbon dioxide absorption efficiency can be increased even when the gas supplied to the carbon dioxide capture device is at a low temperature. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the configuration of a carbon dioxide recovery device according to the first embodiment of this disclosure. [Figure 2] This flowchart shows the flow of the operation method of a carbon dioxide recovery device according to the embodiment of this disclosure. [Figure 3] This figure shows the configuration of a carbon dioxide recovery device according to the second embodiment of this disclosure. [Figure 4] This figure shows the hardware configuration of the control device for a carbon dioxide capture device according to an embodiment of the present disclosure. [Figure 5] This is a functional block diagram of the control device for a carbon dioxide recovery device according to the present disclosure. [Figure 6] This flowchart shows the flow of the operation method of a carbon dioxide recovery device according to the embodiment of this disclosure. [Figure 7] This figure shows the configuration of a carbon dioxide recovery device according to the first modified example of the first and second embodiments of the present disclosure. [Figure 8] This figure shows the configuration of a carbon dioxide recovery device according to a second modified example of the first and second embodiments of the present disclosure. [Figure 9] This figure shows the configuration of a carbon dioxide recovery device according to a third modified example of the first and second embodiments of this disclosure. [Figure 10]This diagram shows the configuration of a carbon dioxide recovery device according to a fourth modification of the first and second embodiments of this disclosure. [Figure 11] This diagram shows the configuration of a carbon dioxide recovery device according to a fifth modified example of the first and second embodiments of this disclosure. [Modes for carrying out the invention]

[0011] The following describes embodiments for implementing the carbon dioxide capture apparatus and the method of operating the carbon dioxide capture apparatus according to this disclosure, with reference to the attached drawings. However, this disclosure is not limited to these embodiments. <First Embodiment> (Configuration of a carbon dioxide capture system) Figure 1 is a diagram showing the configuration of a carbon dioxide recovery device according to the first embodiment of this disclosure. The configurations of the carbon dioxide recovery devices shown in Figure 1 and in each embodiment are schematic diagrams. For the sake of simplification of the schematic diagrams, the flow direction of the low-temperature fluid and the high-temperature fluid in the heat exchangers (first heat exchanger 41, third heat exchanger 43, fourth heat exchanger 46, reboiler (second heat exchanger) 48, condenser (fifth heat exchanger) 49) described later may be shown in opposite directions to the actual flow directions. The carbon dioxide capture device 10A shown in Figure 1 is connected to an emission source (not shown) that emits gas containing carbon dioxide, such as those installed in ships, steel mills, etc. Specifically, in the case of ships, emission sources include, for example, internal combustion engines used in the main engines for propelling the ship, internal combustion engines used in power generation equipment that supplies electricity to the ship, and boilers that generate steam. In the case of steel mills, the emission source is a blast furnace. In such emission sources, carbon dioxide is contained in the gas produced by burning fuel. In the following explanation, gas containing carbon dioxide will be simply referred to as "gas" as appropriate.

[0012] The carbon dioxide recovery unit 10A recovers carbon dioxide contained in the gas from the emission source. The carbon dioxide recovery unit 10A comprises a washing tower 11, an absorption tower 12, a regeneration tower 13, a recovery unit 15, and a heating unit 20A.

[0013] The scrubbing tower 11 cleans the gas from the emission source with the scrubbing liquid L1. When the emission source is installed on a ship, as the scrubbing liquid L1, the water around the floating ship or the fresh water stored in a fresh water tank (not shown) provided inside the ship can be used. When the emission source is installed in a steel mill or the like, as the scrubbing liquid L1, for example, seawater, river water, industrial water, etc. can be used.

[0014] One end of the gas introduction line 101 is connected to the lower part of the scrubbing tower 11. The gas introduction line 101 is provided at the inlet of the carbon dioxide recovery device 10A, and the gas from an emission source (not shown) outside the carbon dioxide recovery device 10A is sent in. The other end of the gas introduction line 101 is connected to a desulfurization device (not shown) provided between the emission source and the scrubbing tower 11. The desulfurization device removes sulfur components such as SO2 contained in the gas. In this embodiment, an inlet temperature detection unit 201 for detecting the temperature of the gas introduced into the carbon dioxide recovery device 10A is provided in the gas introduction line 101.

[0015] The scrubbing tower 11 includes a tower body 11a and a nozzle 11b for spraying the scrubbing liquid L1 from the upper part inside the tower body 11a. A scrubbing liquid supply line 102 for circulating the scrubbing liquid L1 is connected to the scrubbing tower 11. One end of the scrubbing liquid supply line 102 is connected to the bottom of the tower body 11a. The other end of the scrubbing liquid supply line 102 is connected to the nozzle 11b at the upper part of the tower body 11a.

[0016] In the middle of the scrubbing liquid supply line 102, a scrubbing liquid supply pump 31 and a first heat exchanger 41 are provided. The scrubbing liquid supply pump 31 sucks out the scrubbing liquid L1 accumulated at the bottom of the tower body 11a from inside the tower body 11a and supplies it to the nozzle at the upper part of the tower body. The scrubbing liquid L1 supplied to the nozzle 11b is sprayed from the nozzle 11b into the tower body 11a and comes into contact (gas-liquid contact) with the gas sent into the tower body 11a. Thereby, dust etc. contained in the gas are captured by the scrubbing liquid L1 and washed away.

[0017] As will be described in detail later, the first heat exchanger 41 adjusts the temperature of the cleaning solution L1 by performing heat exchange between the cleaning solution L1 flowing through the cleaning solution supply line 102 and the medium flowing through the medium line 107.

[0018] One end of the gas discharge line 103 is connected to the top of the tower body 11a. The gas discharge line 103 sends the gas, which has been cleaned by washing away soot and other debris with a cleaning solution inside the tower body 11a, to the absorption tower 12.

[0019] The absorption tower 12 absorbs carbon dioxide contained in the gas into the absorbent liquid L2. The absorption tower 12 comprises a tower body 12a and nozzles 12b and 12c. Nozzle 12b sprays the absorbent liquid L2 into the tower body 12a, removing carbon dioxide from the gas by bringing it into gas-liquid contact with the gas. Nozzle 12c sprays cleaning water into the tower body 12a, recovering the absorbent liquid L2 sprayed from nozzle 12b contained in the gas by bringing the rising carbon dioxide inside the tower body 12a into contact with the gas from which the carbon dioxide has been removed. The other end of the gas discharge line 103 is connected to the lower part of the tower body 12a. The gas that has passed through the washing tower 11 is sent into the tower body 12a through the gas discharge line 103.

[0020] Nozzle 12b is located in the lower part of the absorption tower 12. Nozzle 12c is located in the upper part of the absorption tower 12. The absorbent liquid L2 is supplied to nozzle 12b from the regeneration tower 13 via a circulation line 106, which will be described later.

[0021] A wash water circulation line 105 is connected to the absorption tower 12 for circulating wash water. One end of the wash water circulation line 105 is connected to the middle section of the tower body 12a. The other end of the wash water circulation line 105 is connected to a nozzle 12c inside the tower body 12a at the top of the tower body 12a. A wash water circulation pump 33 and a third heat exchanger 43 are provided along the wash water circulation line 105. The wash water circulation pump 33 draws wash water from the wash water receiver 12d located in the middle section of the tower body 12a and supplies it to the nozzle 12c at the top of the tower body 12a.

[0022] The absorbent liquid L2 supplied to the nozzle 12b is sprayed into the tower body 12a and comes into contact with the gas sent into the tower body 12a. As a result, the carbon dioxide contained in the gas is absorbed by the absorbent liquid L2 within the tower body 12a of the absorption tower 12.

[0023] A cooling water supply pipe 82A is connected to the third heat exchanger 43. Cooling water is supplied to the third heat exchanger 43 from outside the carbon dioxide recovery device 10A through this cooling water supply pipe 82A. The third heat exchanger 43 performs heat exchange between the cooling water supplied from outside the carbon dioxide recovery device 10A and the cleaning water flowing in the cleaning water circulation line 105. In other words, the third heat exchanger 43 cools the cleaning water circulating in the cleaning water circulation line 105 with the cooling water supplied from outside the carbon dioxide recovery device 10A. The cleaning water cooled by the third heat exchanger 43 is sprayed into the tower body 12a from a nozzle 12c at the top of the tower body 12a.

[0024] One end of the exhaust pipe 12e is connected to the top of the tower body 12a. The exhaust pipe 12e guides the gas that has left the absorption tower 12, in other words, the gas from which the absorbent liquid L2 has been removed by the absorption tower 12, to, for example, an exhaust funnel (not shown) and releases it into the atmosphere.

[0025] The regeneration tower 13 separates gaseous carbon dioxide from the absorbent liquid L2 that absorbed carbon dioxide in the absorption tower 12. The regeneration tower 13 comprises a tower body 13a, a nozzle 13b for spraying the absorbent liquid L2 into the tower body 13a, and a nozzle 13c for spraying the recirculated condensate. The nozzle 13b is located in the lower part of the tower body 13a. The nozzle 13c is located in the upper part of the tower body 13a.

[0026] A circulation line 106 is provided between the absorption tower 12 and the regeneration tower 13. The circulation line 106 circulates the absorbent liquid L2 between the absorption tower 12 and the regeneration tower 13. The circulation line 106 includes an absorbent liquid supply line 106A, an absorbent liquid discharge line 106B, and a heat exchanger 45.

[0027] One end of the absorbent liquid supply line 106A is connected to the bottom of the tower body 13a of the regeneration tower 13. The other end of the absorbent liquid supply line 106A is connected to the nozzle 12b inside the tower body 12a of the absorption tower 12. A first circulation pump 32A and a fourth heat exchanger 46 are provided along the absorbent liquid supply line 106A. The first circulation pump 32A draws absorbent liquid L2 from the bottom of the tower body 13a of the regeneration tower 13 through the absorbent liquid supply line 106A and supplies it to the nozzle 12b inside the tower body 12a of the absorption tower 12.

[0028] A cooling water supply pipe 82B is connected to the fourth heat exchanger 46. Cooling water is supplied to the fourth heat exchanger 46 from outside the carbon dioxide recovery device 10A via the cooling water supply pipe 82B. The fourth heat exchanger 46 performs heat exchange between the cooling water supplied from outside the carbon dioxide recovery device 10A and the absorbent liquid L2 flowing through the absorbent liquid supply line 106A. In other words, the fourth heat exchanger 46 cools the absorbent liquid L2 supplied to the absorption tower 12 through the absorbent liquid supply line 106A by the cooling water supplied from outside the carbon dioxide recovery device 10A. The absorbent liquid L2 cooled by the fourth heat exchanger 46 is sprayed into the tower body 12a from the nozzle 12b of the absorption tower 12.

[0029] One end of the absorbent liquid discharge line 106B is connected to the bottom of the tower body 12a of the absorption tower 12. The other end of the absorbent liquid discharge line 106B is connected to a nozzle 13b located inside the tower body 13a of the regeneration tower 13. A second circulation pump 32B is installed in the middle of the absorbent liquid discharge line 106B. The second circulation pump 32B draws the absorbent liquid L2 from the bottom of the tower body 12a of the absorption tower 12 through the absorbent liquid discharge line 106B and supplies it to the nozzle 13b of the tower body 13a of the regeneration tower 13.

[0030] The heat exchanger 45 performs heat exchange between the absorbent liquid L2 flowing through the absorbent liquid supply line 106A and the absorbent liquid L2 flowing through the absorbent liquid discharge line 106B. In other words, the heat from the absorbent liquid L2 immediately after carbon dioxide has been separated by the regeneration tower 13 heats the absorbent liquid L2 that has absorbed carbon dioxide before it is introduced into the regeneration tower 13.

[0031] The regeneration tower 13 separates gaseous carbon dioxide from the absorbent liquid L2 that has absorbed carbon dioxide in the absorption tower 12. To this end, the regeneration tower 13 heats the absorbent liquid L2 that has been sent into the regeneration tower 13 from the absorption tower 12 via the absorbent liquid discharge line 106B using the absorbent liquid heating line 108.

[0032] The absorbent liquid heating line 108 is connected to the regeneration tower 13. The absorbent liquid heating line 108 circulates the absorbent liquid L2 between the regeneration tower 13 and the reboiler (second heat exchanger) 48. In other words, the absorbent liquid heating line 108 supplies the absorbent liquid L2 taken from the regeneration tower 13 to the reboiler 48, and also returns the absorbent liquid L2 from the reboiler 48 back into the regeneration tower 13. To put it another way, the reboiler 48 is located in the middle of the absorbent liquid heating line 108.

[0033] A steam supply pipe 81 is connected to the reboiler 48. Steam is supplied to the reboiler 48 from a boiler (not shown) located outside the carbon dioxide recovery device 10A via the steam supply pipe 81. The reboiler 48 exchanges heat between the steam supplied through the steam supply pipe 81 and the absorbent liquid L2 flowing through the absorbent liquid heating line 108. In other words, the reboiler 48 heats the absorbent liquid L2 with the heat from the steam.

[0034] The reboiler 48 separates gaseous carbon dioxide from the absorbent liquid L2 by heating it. The absorbent liquid L2 and gaseous carbon dioxide separated in the reboiler 48 are returned to the tower body 13a through the absorbent liquid heating line 108. In this way, the absorbent liquid L2, from which gaseous carbon dioxide has been separated and regenerated, is returned to the absorption tower 12 through the absorbent liquid supply line 106A and reused. Meanwhile, the separated gaseous carbon dioxide is sent to the recovery section 15 through the gaseous carbon dioxide discharge line 109.

[0035] A condenser (fifth heat exchanger) 49 is installed in the middle of the gaseous carbon dioxide discharge line 109. A cooling water supply pipe 82C is connected to the condenser 49. Cooling water is supplied to the condenser 49 from outside the carbon dioxide recovery device 10A via the cooling water supply pipe 82C. The condenser 49 condenses the water contained in the gaseous carbon dioxide through heat exchange with the cooling water supplied from outside the carbon dioxide recovery device 10A.

[0036] The recovery unit 15 recovers the gaseous carbon dioxide separated in the regeneration tower 13. The recovery unit 15 is a gas-liquid separator that separates the gaseous carbon dioxide sent in via the condenser 49 from the condensed water formed by the condensation of water.

[0037] The gas-liquid separated condensate is returned to the regeneration tower 13 from the bottom of the recovery section 15 through the recirculation line 110. A recirculation pump 112 is provided in the middle of the recirculation line 110 to return the condensate to the regeneration tower 13. The recirculation line 110 is connected to a nozzle 13c located at the top of the regeneration tower 13. The condensate returned to the regeneration tower 13 is sprayed as absorbent liquid L2 into the tower body 13a from the nozzle 13c of the regeneration tower 13.

[0038] On the other hand, the gaseous carbon dioxide from which water has been removed in the recovery section 15 is discharged to the outside of the carbon dioxide recovery device 10A through the carbon dioxide discharge pipe 111. The gaseous carbon dioxide discharged through the carbon dioxide discharge pipe 111 is stored, for example, in a carbon dioxide recovery tank (not shown). In this case, the gaseous carbon dioxide may be liquefied using an appropriate carbon dioxide liquefaction device and stored in the carbon dioxide recovery tank.

[0039] In the carbon dioxide recovery system 10A described above, the gas emitted from the emission source (not shown) is washed away in the scrubbing tower 11 and then introduced into the absorption tower 12. In the absorption tower 12, carbon dioxide contained in the gas is absorbed by the absorbent liquid L2. As carbon dioxide is absorbed by the absorbent liquid L2, the gas from which carbon dioxide has been separated is released into the atmosphere. The absorbent liquid L2 that has absorbed carbon dioxide contained in the gas in the absorption tower 12 is sent to the regeneration tower 13 via the circulation line 106. The absorbent liquid L2 that has absorbed carbon dioxide is heated by the reboiler 48 to raise its temperature, and the gaseous carbon dioxide contained in the absorbent liquid L2 is separated. The separated gaseous carbon dioxide is recovered via the recovery section 15. Meanwhile, the absorbent liquid L2 from which carbon dioxide has been separated in the regeneration tower 13 is circulated back to the absorption tower 12 via the circulation line 106.

[0040] (Configuration of the heating section) The heating unit 20A heats the gas supplied to the absorption tower 12. The heating unit 20A heats the gas when the temperature of the gas supplied to the absorption tower 12 is lower than a preset reference temperature. Here, the reference temperature is preferably set to, for example, 0°C. The reference temperature is not limited to 0°C, but can be set to 5°C, 10°C, etc., as appropriate.

[0041] In this embodiment, the heating unit 20A supplies a heat transfer medium at a higher temperature than the cleaning liquid L1 and the gas sent into the cleaning tower 11 to the first heat exchanger 41, thereby causing heat exchange between the heat transfer medium and the cleaning liquid L1 in the first heat exchanger 41 and heating the cleaning liquid L1.

[0042] In this embodiment, the heating unit 20A includes a heat source 21, a heat transfer medium supply line 122, and a heat transfer medium recovery line 121. The heat source 21 is, for example, an electric heater. The heat source 21 may also be a boiler that generates steam. Alternatively, the heat source 21 may introduce steam generated by a boiler or the like located outside the carbon dioxide recovery device 10A. The heat source 21 heats the heat transfer medium, such as water, to a temperature higher than that of the cleaning solution L1 and the gas supplied into the cleaning tower 11. An example of the temperature of the heat transfer medium heated by the heat source 21 is 30°C to 50°C. However, the temperature of the heat transfer medium may be other than those exemplified here.

[0043] The heat transfer medium supply line 122 and the heat transfer medium recovery line 121 connect the heat source 21 and the medium line 107. The heat transfer medium supply line 122 supplies the heat transfer medium heated by the heat source 21 to the medium line 107. The heat transfer medium supplied to the medium line 107 heats the cleaning liquid L1 flowing through the cleaning liquid supply line 102 by exchanging heat with the cleaning liquid L1 in the first heat exchanger 41. The heat transfer medium recovery line 121 recovers the heat transfer medium that has passed through the first heat exchanger 41 from the medium line 107 and returns it to the heat source 21.

[0044] On-off valves 122v and 121v are provided in the heat transfer medium supply line 122 and the heat transfer medium recovery line 121. By opening and closing valves 122v and 121v, the supply of heat transfer medium from the heating unit 20A to the first heat exchanger 41 can be interrupted.

[0045] Furthermore, the media line 107 is connected to a refrigerant supply line 104A and a refrigerant discharge line 104B. The refrigerant supply line 104A supplies a refrigerant at a lower temperature than the cleaning liquid L1, such as water, to the media line 107 from outside the carbon dioxide recovery device 10A. The refrigerant supplied to the media line 107 cools the cleaning liquid L1 by exchanging heat with the cleaning liquid L1 flowing through the cleaning liquid supply line 102 in the first heat exchanger 41. The refrigerant discharge line 104B discharges the refrigerant that has passed through the first heat exchanger 41 from the media line 107.

[0046] On-off valves 104v and 104w are provided in the middle of the refrigerant supply line 104A and the refrigerant discharge line 104B. By opening and closing valves 104v and 104w, the supply of refrigerant to the first heat exchanger 41 can be interrupted.

[0047] In this embodiment, the carbon dioxide recovery device 10A opens and closes the on-off valves 104v, 104w, 121v, and 122v based on the gas temperature detected by the inlet temperature detection unit 201. When the on-off valves 104v and 104w are closed and the on-off valves 121v and 122v are opened in the carbon dioxide recovery device 10A, a heat transfer medium is supplied to the medium line 107 from the heating unit 20A. When the on-off valves 121v and 122v are closed and the on-off valves 104v and 104w are opened, a refrigerant is supplied to the medium line 107 from the refrigerant supply line 104A. Here, the opening and closing of the valves 104v, 104w, 121v, and 122v described above can be performed, for example, by a worker remotely from the control room of the carbon dioxide recovery device 10A, or by manual operation.

[0048] (Operating procedure for carbon dioxide capture equipment) Figure 2 is a flowchart showing the flow of the operation method of a carbon dioxide capture device according to the present disclosure. As shown in Figure 2, the operating method S10 of the carbon dioxide recovery apparatus according to this embodiment includes a step S11 for detecting the gas inlet temperature, a step S12 for confirming whether the inlet temperature is lower than a reference temperature, a step S13 for heating the gas, and a step S14 for cooling the gas.

[0049] In step S11, which detects the gas inlet temperature, the inlet temperature detection unit 201 detects the temperature of the gas being supplied through the gas introduction line 101. In step S12, which checks whether the inlet temperature is lower than the reference temperature, the temperature of the detected gas is checked to see if it is lower than a preset reference temperature.

[0050] As a result, if the gas temperature is lower than the reference temperature (step S12: Yes), the process proceeds to step S13. In step S13, where the gas is heated, the heating unit 20A heats the gas sent to the absorption tower 12. In this embodiment, in step S13, the on-off valves 104v and 104w are closed, and the on-off valves 121v and 122v are opened. As a result, a heat transfer medium at a higher temperature than the cleaning liquid L1 is sent to the first heat exchanger 41, heating the cleaning liquid L1. In this way, by heating the cleaning liquid L1 supplied to the scrubbing tower 11, the gas sent to the gas introduction line 101 is cleaned and heated in the scrubbing tower 11.

[0051] Furthermore, if the gas temperature is above the reference temperature in step S12 (step S12: No), the process proceeds to step S14. In step S14, where the gas is cooled, valves 121v and 122v are closed, and valves 104v and 104w are opened. As a result, a refrigerant at a lower temperature than the cleaning liquid L1 is sent to the first heat exchanger 41, cooling the cleaning liquid L1. This cleans and cools the gas that comes into contact with the cleaning liquid L1 in the cleaning tower 11.

[0052] (Effects and Benefits) In the carbon dioxide recovery device 10A with the above configuration, the heating unit 20A heats the gas sent to the absorption tower 12. This allows the temperature of the gas sent to the absorption tower 12 to be increased even when the gas sent to the carbon dioxide recovery device 10A is at a low temperature. Therefore, the carbon dioxide absorption efficiency in the absorption tower 12 can be increased. As a result, the carbon dioxide absorption efficiency can be increased even when the gas sent to the carbon dioxide recovery device 10A is at a low temperature.

[0053] Furthermore, the heating unit 20A heats the gas when its temperature is lower than a preset reference temperature. This prevents the gas from being heated more than necessary.

[0054] Furthermore, the heating unit 20A supplies a heat transfer medium at a higher temperature than the cleaning liquid L1 to the first heat exchanger 41 located in the cleaning liquid supply line 102, and heats the cleaning liquid L1 by exchanging heat between the heat transfer medium and the cleaning liquid L1. As a result, in the cleaning tower 11, the gas sent to the gas introduction line 101 comes into contact with the cleaning liquid L1 heated in the first heat exchanger 41, causing its temperature to rise. This increases the carbon dioxide absorption efficiency in the absorption tower 12.

[0055] Furthermore, the first heat exchanger 41 cools the cleaning solution L1 when the gas temperature is above a preset reference temperature. In other words, when the gas temperature in the scrubbing tower 11 is higher than the reference temperature, the scrubbing tower 11 cools the gas with the cleaning solution L1 cooled by the first heat exchanger 41, and when the gas temperature is lower than the reference temperature, it heats the cleaning solution L1 to heat the gas. In this way, the first heat exchanger 41 can be used for both cooling and heating the gas, so there is no need to add a separate heat exchanger for heating the gas. Therefore, even when the gas sent to the carbon dioxide recovery device 10A is at a low temperature, the carbon dioxide absorption efficiency can be increased at a low cost.

[0056] Furthermore, the heating unit 20A is equipped with a heat source 21 for heating the heat transfer medium. By supplying the heat transfer medium heated by the heat source 21 to the first heat exchanger 41, the cleaning liquid L1 is heated, and the temperature of the gas sent to the carbon dioxide recovery device 10A can be increased.

[0057] In the operation method S10 of the carbon dioxide recovery device 10A with the above configuration, the temperature of the gas supplied to the absorption tower 12 can be increased when the gas supplied to the carbon dioxide recovery device 10A is within a preset range. Therefore, even when the gas supplied to the carbon dioxide recovery device 10A is at a low temperature, the carbon dioxide absorption efficiency can be increased.

[0058] <Second Embodiment> Next, a second embodiment of the carbon dioxide recovery apparatus and the method of operating the carbon dioxide recovery apparatus according to this disclosure will be described. In the second embodiment described below, components common to the first embodiment are denoted by the same reference numerals in the figures and their descriptions are omitted. The second embodiment differs from the first embodiment in that it has a control device 60.

[0059] Figure 3 shows the configuration of a carbon dioxide capture device according to the second embodiment of this disclosure. As shown in Figure 3, the carbon dioxide recovery device 10B comprises a washing tower 11, an absorption tower 12, a regeneration tower 13, a recovery unit 15, a heating unit 20B, and a control device 60 that controls the heating unit 20B.

[0060] In this embodiment, the carbon dioxide recovery device 10B is equipped with a flow control valve 122w provided in the heat transfer medium supply line 122.

[0061] Furthermore, in this embodiment, the carbon dioxide recovery device 10B includes, in addition to the inlet temperature detection unit 201, a first outlet temperature detection unit 202 and a second outlet temperature detection unit 203. The first outlet temperature detection unit 202 detects the temperature of the gas flowing through the gas discharge line 103 at the outlet of the scrubbing tower 11. The second outlet temperature detection unit 203 detects the temperature of the gas discharged through the exhaust pipe 12e at the outlet of the absorption tower 12.

[0062] Furthermore, the carbon dioxide recovery device 10B in this embodiment is equipped with a replenishment line 210. One end of the replenishment line 210 is connected to the scrubbing tower 11. The other end of the replenishment line 210 is connected to a makeup water supply line (not shown) through which industrial water flows, for example. The replenishment line 210 can supply the scrubbing tower 11 with industrial water supplied from the makeup water supply line as makeup water.

[0063] (Hardware configuration diagram) Figure 4 shows the hardware configuration of the control device for a carbon dioxide capture device according to the present disclosure. As shown in Figure 4, the control device 60 is a computer equipped with a processor 61 such as a CPU (Central Processing Unit), ROM 62 (Read Only Memory), RAM 63 (Random Access Memory), storage 64, and a signal transmission / reception module 65. The signal transmission / reception module 65 receives signals related to the gas temperature from the inlet temperature detection unit 201, the first outlet temperature detection unit 202, and the second outlet temperature detection unit 203, respectively.

[0064] (Functional block diagram) Figure 5 is a functional block diagram of the control device for a carbon dioxide recovery system according to an embodiment of this disclosure. As shown in Figure 5, the processor 61 of the control device 60 realizes the configurations of the signal input unit 70, information acquisition unit 71, valve control unit 72, and output unit 75 by executing a program pre-stored in a storage device such as ROM 62 or storage 64. The signal input unit 70 receives signals related to the gas temperature from the inlet temperature detection unit 201, the first outlet temperature detection unit 202, and the second outlet temperature detection unit 203, respectively, via the hardware signal transmission / reception module 65.

[0065] The information acquisition unit 71 acquires the gas temperature values ​​detected by the inlet temperature detection unit 201, the first outlet temperature detection unit 202, and the second outlet temperature detection unit 203, respectively, based on the signals received by the signal input unit 70.

[0066] The valve control unit 72 heats the gas supplied to the absorption tower 12 in the heating unit 20B based on the gas temperature detected by the inlet temperature detection unit 201. The valve control unit 72 heats the gas supplied to the absorption tower 12 in the heating unit 20B if the gas inlet temperature detected by the inlet temperature detection unit 201 is lower than a preset reference temperature.

[0067] Furthermore, the valve control unit 72 controls the opening degree of the flow control valve 122w based on the gas temperature detected by the inlet temperature detection unit 201, the first outlet temperature detection unit 202, and the second outlet temperature detection unit 203, respectively. The valve control unit 72 calculates the difference between the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203. The valve control unit 72 controls the opening degree of the flow rate control valve 122w so that the difference between the gas temperature detected by the first outlet temperature detection unit 202 and the gas temperature detected by the second outlet temperature detection unit 203 falls within a preset range.

[0068] The output unit 75 outputs a control signal to change the opening degree of the flow control valve 122w based on the control of the valve control unit 72.

[0069] (Operating procedure for carbon dioxide capture equipment) Figure 6 is a flowchart showing the flow of the operation method of a carbon dioxide recovery device according to the present disclosure. In this embodiment, the operation method S20 of the carbon dioxide recovery device shown below is realized by the control device 60 sequentially executing processes based on a pre-stored program. As shown in Figure 6, the operating method S20 of the carbon dioxide recovery apparatus according to this embodiment includes a step S21 for detecting the gas inlet temperature, a step S22 for confirming whether the inlet temperature is lower than a reference temperature, a step S23 for heating the gas, and a step S24 for cooling the gas.

[0070] In step S21, which detects the gas inlet temperature, the inlet temperature detection unit 201 detects the temperature of the gas being supplied through the gas introduction line 101. The inlet temperature detection unit 201 transmits a signal related to the detected gas temperature to the control device 60. The signal input unit 70 of the control device 60 receives the signal related to the gas temperature from the inlet temperature detection unit 201. The information acquisition unit 71 acquires the value of the gas inlet temperature from the inlet temperature detection unit 201 based on the signal received by the signal input unit 70.

[0071] In step S22, which checks whether the inlet temperature is lower than the reference temperature, the valve control unit 72 checks whether the detected gas inlet temperature is lower than the preset reference temperature, based on the gas inlet temperature obtained from the inlet temperature detection unit 201 by the information acquisition unit 71.

[0072] As a result, in step S22, if the gas temperature is above the reference temperature (step S22: No), the valve control unit 72 closes the on-off valve 121v and the flow rate control valve 122w, and opens the on-off valves 104v and 104w. Then, in the first heat exchanger 41, the cleaning liquid L1 is cooled by exchanging heat between the cleaning liquid L1 and a refrigerant at a lower temperature than the cleaning liquid L1. In this way, the gas in contact with the cleaning liquid L1 in the cleaning tower 11 is cleaned and cooled.

[0073] Furthermore, if the gas temperature is lower than the reference temperature in step S22 (step S22: Yes), the control device 60 starts the process of heating the gas sent to the absorption tower 12 in the heating unit 20B in step S23, which is the gas heating step, in the procedure shown below. Step S23, which is the gas heating step, includes step S231, which sets a target value for the opening degree of the flow control valve 122w; step S232, which sets a target value for the gas temperature at the outlet of the scrubbing tower 11; and step S233, which adjusts the opening degree of the flow control valve 122w.

[0074] In step S231, which sets the target value for the opening degree of the flow control valve 122w, the valve control unit 72 calculates an estimated value for the opening degree of the flow control valve 122w based on the inlet temperature of the gas sent to the scrubbing tower 11 through the gas introduction line 101, as detected by the inlet temperature detection unit 201, and the operating conditions of the carbon dioxide recovery device 10B. The valve control unit 72 sets the calculated estimated value for the opening degree as the target value for the opening degree of the flow control valve 122w. Here, the operating conditions for the carbon dioxide recovery device 10B can be exemplified by the ambient temperature. More specifically, for example, in summer, when the ambient temperature is 20°C or higher, the gas inlet temperature will also be 20°C or higher, and in such cases, heating of the gas by the heating unit 20B is unnecessary. On the other hand, in winter, when the ambient temperature is 0°C or lower, the gas inlet temperature will also be 0°C or lower, so the target value for the opening of the flow control valve 122w is set to, for example, 0% to 50% in order to heat the gas in the heating unit 20B. Furthermore, when the ambient temperature is -10°C or lower and the gas inlet temperature is also -10°C or lower, the target value for the opening of the flow control valve 122w is set to, for example, 50% to 100% in order to further heat the gas by the heating unit 20B. It goes without saying that the ambient temperature, gas inlet temperature, and opening of the flow control valve 122w exemplified here are merely examples and can be changed as appropriate.

[0075] In step S232, which sets a target value for the gas temperature at the outlet of the scrubbing tower 11, the valve control unit 72 acquires the measured value of the gas temperature at the outlet of the absorption tower 12, which is detected by the second outlet temperature detection unit 203. Based on the measured value of the gas temperature at the outlet of the absorption tower 12, the valve control unit 72 sets a target value for the gas temperature at the outlet of the scrubbing tower 11. The valve control unit 72 determines that if the gas temperature at the inlet of the carbon dioxide recovery device 10B is low, the amount of moisture in the gas in the absorption tower 12 may be insufficient. If the amount of moisture in the gas in the absorption tower 12 is insufficient, makeup water must be supplied to the absorption tower 12. When supplying makeup water to the absorption tower 12, pure water must be used as makeup water to prevent the contamination of the absorbent liquid L2 in the absorption tower 12 with impurities. However, using pure water as makeup water is costly. In this embodiment, the valve control unit 72 sets a target value for the gas temperature at the outlet of the scrubbing tower 11 so that makeup water does not need to be supplied to the absorption tower 12. Specifically, the valve control unit 72 makes the difference between the gas temperature at the inlet of the absorption tower 12, i.e., the outlet of the scrubbing tower 11, and the gas temperature at the outlet of the absorption tower 12 small so that makeup water does not need to be supplied to the absorption tower 12. Therefore, in step S232, the valve control unit 72 sets a target value for the gas temperature at the outlet of the scrubbing tower 11, based on the measured value of the gas temperature at the outlet of the absorption tower 12 detected by the second outlet temperature detection unit 203, so that the difference between the gas temperature at the outlet of the absorption tower 12 and the gas temperature at the outlet of the scrubbing tower 11 falls within a preset range. The valve control unit 72 sets the target value for the gas temperature at the outlet of the scrubbing tower 11, for example, "Measured gas temperature at the outlet of absorption tower 12 ± 1°C" Set the range to be such.

[0076] In step S233, which adjusts the opening degree of the flow control valve 122w, the valve control unit 72 adjusts the opening degree of the flow control valve 122w so that the gas temperature at the outlet of the scrubbing tower 11 approaches the target value set in step S232, while the absorption tower 12 absorbs carbon dioxide contained in the gas. Specifically, the valve control unit 72 controls the flow rate control valve 122w to open at the target opening value set in step S231. As a result, a heat transfer medium at a higher temperature than the cleaning liquid L1 is supplied to the first heat exchanger 41 at a flow rate corresponding to the opening degree of the flow rate control valve 122w, and the cleaning liquid L1 is heated. This causes the temperature of the gas from the cleaning tower 11 to rise as it comes into contact with the heated cleaning liquid L1 within the cleaning tower 11. In step S233, the valve control unit 72 acquires the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203, at predetermined time intervals. The valve control unit 72 calculates the difference between the acquired gas temperature at the outlet of the scrubbing tower 11 and the gas temperature at the outlet of the absorption tower 12. The valve control unit 72 determines whether the calculated difference is within the range set in step S232, and controls the opening degree of the flow rate control valve 122w based on the determination result.

[0077] If the gas temperature at the outlet of the scrubbing tower 11 is lower than the gas temperature at the outlet of the absorption tower 12, and the calculated difference exceeds the range of the target value set in step S232, the valve control unit 72 determines that the gas heating in the scrubbing tower 11 is insufficient and increases the opening of the flow rate control valve 122w. Furthermore, if the gas temperature at the outlet of the scrubbing tower 11 is higher than the gas temperature at the outlet of the absorption tower 12, and the difference exceeds the range of the target value set in step S232, the valve control unit 72 determines that the gas in the scrubbing tower 11 is being overheated and reduces the opening of the flow rate control valve 122w. Furthermore, if the calculated difference is within the range of the target value set in step S232, the valve control unit 72 determines that there is no overheating or underheating of the gas in the scrubbing tower 11 and maintains the opening of the flow control valve 122w.

[0078] In step S233, the valve control unit 72 controls the opening degree of the flow control valve 122w based on the difference between the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203. However, it is not limited to this. For example, in step S233, the valve control unit 72 may control the opening degree of the flow control valve 122w based on the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the target value of the gas temperature at the outlet of the scrubbing tower 11 set in step S232. In step S232, the target value of the gas temperature at the outlet of the scrubbing tower 11 is set based on the measured value of the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203. Therefore, the control of the opening degree of the flow control valve 122w in step S233 is essentially performed based on the difference between the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203.

[0079] (Effects and Benefits) In the carbon dioxide recovery device 10B and the operating method S20 of the carbon dioxide recovery device 10B with the above configuration, the gas sent to the absorption tower 12 is heated in the heating unit 20B, similar to the first embodiment. This makes it possible to raise the temperature of the gas sent to the absorption tower 12 even when the gas sent to the carbon dioxide recovery device 10B is at a low temperature. Therefore, even when the gas sent to the carbon dioxide recovery device 10B is at a low temperature, the carbon dioxide absorption efficiency can be increased.

[0080] Furthermore, the control device 60 controls the heating unit 20B based on the inlet temperature of the gas supplied through the gas introduction line 101. This allows the carbon dioxide absorption efficiency to be automatically increased according to the gas inlet temperature, even when the gas supplied to the carbon dioxide recovery device 10B is at a low temperature.

[0081] Furthermore, the control device 60 heats the gas sent to the absorption tower 12 in the heating unit 20B when the gas inlet temperature is within a preset range. This automatically increases the carbon dioxide absorption efficiency when the gas sent to the carbon dioxide recovery device 10B is at a low temperature.

[0082] Furthermore, the control device 60 controls the heating unit 20B so that the difference between the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203, falls within a preset range. This reduces the difference between the gas temperature at the outlet of the scrubbing tower 11 and the gas temperature at the outlet of the absorption tower 12, resulting in a relatively lower inlet temperature of the gas sent to the carbon dioxide recovery device 10B through the gas introduction line 101 relative to the gas temperature at the outlets of the scrubbing tower 11 and the absorption tower 12. When the inlet gas temperature is lower, the amount of water contained in the gas in the scrubbing tower 11 decreases. Therefore, makeup water is supplied to the scrubbing tower 11 through the makeup line 210. In this way, it is possible to prevent the mass balance of the absorbent liquid L2 in the absorption tower 12 within the carbon dioxide recovery device 10B system from being disrupted. In this case, when supplying makeup water to the scrubbing tower 11, cheaper industrial water can be used as makeup water compared to pure water, thus suppressing the increase in operating costs of the carbon dioxide capture device 10B.

[0083] (First modified example of the first and second embodiments) In the first and second embodiments described above, the heating sections 20A and 20B are equipped with a heat source 21, but the invention is not limited to this. Figure 7 shows the configuration of a carbon dioxide recovery device according to the first modified example of the first and second embodiments of this disclosure. As shown in Figure 7, in this modified example, the heating section 20C of the carbon dioxide recovery device 10C supplies steam that has passed through the second heat exchanger 48 to the first heat exchanger 41 as a heat transfer medium through the heat transfer medium supply line 122C. The steam that has passed through the first heat exchanger 41 is returned to the downstream side of the reboiler 48 through the heat transfer medium recovery line 121C.

[0084] In this carbon dioxide recovery device 10C, the second heat exchanger 48 heats the absorbent liquid L2 supplied to the regeneration tower 13 with steam supplied from an external source. The temperature of the steam that has passed through the second heat exchanger 48 is reduced due to heat exchange with the absorbent liquid L2. In the heating section 20C, the steam that has passed through the second heat exchanger 48 is supplied to the first heat exchanger 41 as a heat transfer medium, thereby effectively utilizing the thermal energy of the steam that has passed through the second heat exchanger 48.

[0085] (Second modified example of the first and second embodiments) Figure 8 shows the configuration of a carbon dioxide recovery device according to a second modified example of the first and second embodiments of this disclosure. As shown in Figure 8, in this modified example, the heating section 20D of the carbon dioxide recovery device 10D heats the heat transfer medium supplied to the first heat exchanger 41 using waste heat obtained by cooling the wash water in the third heat exchanger 43. The cooling water that has passed through the third heat exchanger 43 has its temperature increased by cooling the wash water 2 in the third heat exchanger 43. The cooling water whose temperature has increased after passing through the third heat exchanger 43 is supplied to the first heat exchanger 41 as a heat transfer medium through the heat transfer medium supply line 122D. The heat transfer medium (cooling water) that has passed through the first heat exchanger 41 is returned to the downstream side of the third heat exchanger 43 through the heat transfer medium recovery line 121D.

[0086] With this carbon dioxide recovery device 10D, the third heat exchanger 43 cools the wash water that is circulated in the absorption tower 12. The heating unit 20D uses the waste heat obtained by cooling the wash water in the third heat exchanger 43 to heat the heat transfer medium, thereby effectively utilizing the waste heat from the wash water obtained in the third heat exchanger 43.

[0087] (Third modified example of the first and second embodiments) Figure 9 shows the configuration of a carbon dioxide recovery device according to a third modified example of the first and second embodiments of this disclosure. As shown in Figure 9, in this modified example, the heating section 20E of the carbon dioxide recovery device 10E heats the heat transfer medium supplied to the first heat exchanger 41 using the waste heat obtained by cooling the absorbent liquid L2 in the fourth heat exchanger 46. The cooling water that has passed through the fourth heat exchanger 46 has its temperature increased by cooling the absorbent liquid L2 in the fourth heat exchanger 46. The cooling water whose temperature has increased after passing through the fourth heat exchanger 46 is supplied to the first heat exchanger 41 as a heat transfer medium through the heat transfer medium supply line 122E. The heat transfer medium (cooling water) that has passed through the first heat exchanger 41 is returned to the downstream side of the fourth heat exchanger 46 through the heat transfer medium recovery line 121E.

[0088] With this carbon dioxide recovery device 10E, the fourth heat exchanger 46 cools the absorbent liquid L2 that has been regenerated in the regeneration tower 13. The heating unit 20E uses the waste heat obtained by cooling the absorbent liquid L2 in the fourth heat exchanger 46 to heat the heat transfer medium, thereby effectively utilizing the waste heat from the absorbent liquid L2 obtained in the fourth heat exchanger 46.

[0089] (Fourth modification of the first and second embodiments) Figure 10 shows the configuration of a carbon dioxide recovery device according to a fourth modification of the first and second embodiments of this disclosure. As shown in Figure 10, in this modified example, the heating section 20F of the carbon dioxide recovery device 10F heats the heat transfer medium supplied to the first heat exchanger 41 using the waste heat obtained by cooling gaseous carbon dioxide in the condenser 49. The cooling water that has passed through the condenser 49 has increased in temperature due to the cooling of gaseous carbon dioxide in the condenser 49. The cooling water that has increased in temperature after passing through the condenser 49 is supplied to the first heat exchanger 41 as a heat transfer medium through the heat transfer medium supply line 122F. The heat transfer medium (cooling water) that has passed through the first heat exchanger 41 is returned to the downstream side of the condenser 49 through the heat transfer medium recovery line 121F.

[0090] In this carbon dioxide recovery device 10F, the condenser 49 cools the gaseous carbon dioxide separated in the regeneration tower 13. The heating unit 20F uses the waste heat obtained by cooling the gaseous carbon dioxide in the condenser 49 to heat the heat transfer medium, thereby effectively utilizing the waste heat obtained from the carbon dioxide in the condenser 49.

[0091] (Fifth modification of the first and second embodiments) Figure 11 shows the configuration of a carbon dioxide recovery device according to a fifth modification of the first and second embodiments of this disclosure. As shown in Figure 11, the carbon dioxide recovery device 10G in this modified example comprises a desulfurization device 301 and a heat recovery device 302. The desulfurization device 301 removes sulfur from the gas contained in the gas from the emission source (not shown) that is fed through the gas introduction line 101. The heat recovery device 302 is located upstream of the desulfurization device 301 in the gas flow direction and recovers heat from the gas.

[0092] In this modified example, the heating unit 20G heats the heat transfer medium supplied to the first heat exchanger 41 using the heat recovered by the heat recovery unit 302. The heat transfer medium, heated by recovering heat from the gas via the heat recovery unit 302, is supplied to the first heat exchanger 41 through the heat transfer medium supply line 122G. The heat transfer medium that has passed through the first heat exchanger 41 is returned to the upstream side of the fifth heat exchanger 49 through the heat transfer medium recovery line 121G.

[0093] With such a carbon dioxide recovery device 10G, the heating unit 20G can effectively utilize the thermal energy of the gas by heating the heat transfer medium with heat recovered from the high-temperature gas before desulfurization in the heat recovery device 302.

[0094] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure. In the above embodiments and modifications, the heating of the heat transfer medium in the heating sections 20A to 20G is performed based on the gas temperature detected by the inlet temperature detection section 201, but this is not limited to this. The heating of the heat transfer medium in the heating sections 20A to 20G may also be performed based on the ambient temperature, or in the case of a ship, the seawater temperature, etc.

[0095] Furthermore, in each of the above embodiments and modifications, the inlet temperature detection unit 201 for detecting the temperature of the gas introduced into the carbon dioxide recovery devices 10A to 10G is provided in the gas introduction line 101, but this is not limited to this. The inlet temperature detection unit 201 may also be provided in the gas discharge line 103 that sends the gas to the absorption tower 12 via the scrubbing tower 11, and the temperature of the gas may be detected at the inlet of the absorption tower 12.

[0096] Furthermore, in the above embodiments and modifications, the heating sections 20A to 20G are used to heat the cleaning liquid L1 supplied to the cleaning tower 11 in order to heat the gas sent to the absorption tower 12, but this is not limited to this. For example, the heating sections 20A to 20G may be used to heat the gas in the gas introduction line 101.

[0097] <Note> The carbon dioxide recovery devices 10A to 10G and the operating methods S10 and S20 of the carbon dioxide recovery devices 10A to 10G described in each embodiment can be understood, for example, as follows.

[0098] (1) The carbon dioxide recovery apparatus 10A to 10G according to the first embodiment comprises a gas introduction line 101 into which a gas containing carbon dioxide is supplied from the outside; a washing tower 11 that washes the gas by bringing a washing liquid L1 into contact with the gas supplied to the gas introduction line 101; an absorption tower 12 into which an absorbent liquid L2 capable of absorbing carbon dioxide in the gas is introduced and the absorbent liquid L2 absorbs the carbon dioxide in the gas that has passed through the washing tower 11; a regeneration tower 13 that heats the absorbent liquid L2 that has absorbed carbon dioxide, separates carbon dioxide from the absorbent liquid L2 and regenerates the absorbent liquid L2; and heating units 20A to 20G that heat the gas supplied to the absorption tower 12.

[0099] This carbon dioxide capture device 10A-10G heats the gas sent to the absorption tower 12 in the heating sections 20A-20G. This allows the temperature of the gas sent to the absorption tower 12 to be increased even when the gas sent to the carbon dioxide capture device 10A-10G is at a low temperature. Therefore, the carbon dioxide absorption efficiency in the absorption tower 12 can be increased. As a result, the carbon dioxide absorption efficiency can be increased even when the gas sent to the carbon dioxide capture device 10A-10G is at a low temperature.

[0100] (2) The carbon dioxide recovery devices 10A to 10G according to the second embodiment are the carbon dioxide recovery devices 10A to 10G of (1), wherein the heating units 20A to 20G heat the gas when the temperature of the gas is lower than a preset reference temperature.

[0101] This prevents the gas from being heated unnecessarily by heating the gas when its temperature is below a preset reference temperature.

[0102] (3) The carbon dioxide recovery apparatus 10A to 10G according to the third embodiment is the carbon dioxide recovery apparatus 10A to 10G of (1) or (2), further comprising a cleaning liquid supply line 102 connected to the cleaning tower 11 and supplying the cleaning liquid L1 to the cleaning tower 11, and a first heat exchanger 41 provided in the cleaning liquid supply line 102, wherein the heating section 20A to 20G supplies the first heat exchanger 41 with a heat transfer medium at a higher temperature than the cleaning liquid L1, and heats the cleaning liquid L1 by exchanging heat between the heat transfer medium and the cleaning liquid L1.

[0103] As a result, the first heat exchanger 41 heats the cleaning liquid L1 supplied to the cleaning tower 11, causing the gas sent to the gas introduction line 101 in the cleaning tower 11 to come into contact with the heated cleaning liquid L1 and increase in temperature. This increases the carbon dioxide absorption efficiency in the absorption tower 12.

[0104] (4) The carbon dioxide recovery devices 10A to 10G according to the fourth embodiment are the carbon dioxide recovery devices 10A to 10G of (3), wherein the first heat exchanger 41 cools the cleaning liquid L1 by exchanging heat between the cleaning liquid L1 and a refrigerant at a lower temperature than the cleaning liquid L1 when the temperature of the gas is above a preset reference temperature.

[0105] As a result, the first heat exchanger 41 cools the cleaning solution L1 when the gas temperature is above a preset reference temperature. In other words, the scrubbing tower 11 cools the gas with the cleaning solution L1 cooled by the first heat exchanger 41 when the gas temperature is higher than the reference temperature, and heats the cleaning solution L1 to heat the gas when the gas temperature is lower than the reference temperature. In this way, the first heat exchanger 41 can be used for both cooling and heating the gas, so there is no need to add a separate heat exchanger for heating the gas. Therefore, even when the gas supplied to the carbon dioxide recovery devices 10A~10G is at a low temperature, the carbon dioxide absorption efficiency can be increased at a low cost.

[0106] (5) The carbon dioxide recovery device 10A according to the fifth embodiment is the carbon dioxide recovery device 10A of (3) or (4), wherein the heating unit 20A is equipped with a heat source 21 for heating the heat transfer medium.

[0107] This allows the heat transfer medium heated by the heat source 21 to be supplied to the first heat exchanger 41, thereby heating the cleaning liquid L1 and increasing the temperature of the gas sent to the carbon dioxide recovery device 10A. Examples of heat sources 21 include electric heaters and boilers.

[0108] (6) The carbon dioxide recovery device 10C according to the sixth embodiment is any one of the carbon dioxide recovery devices 10C from (3) to (5), further comprising a second heat exchanger 48 that heats the absorbent liquid L2 supplied to the regeneration tower 13 with steam supplied from the outside, and the heating unit 20C supplies the steam that has passed through the second heat exchanger 48 to the first heat exchanger 41 as the heat transfer medium.

[0109] As a result, in the second heat exchanger 48, the absorbent liquid L2 supplied to the regeneration tower 13 is heated by steam supplied from the outside. Due to heat exchange with the absorbent liquid L2, the temperature of the steam that has passed through the second heat exchanger 48 is reduced. In the heating section 20C, the steam that has passed through the second heat exchanger 48 is supplied to the first heat exchanger 41 as a heat transfer medium, thereby effectively utilizing the thermal energy of the steam that has passed through the second heat exchanger 48.

[0110] (7) The carbon dioxide recovery apparatus 10D according to the seventh embodiment is any one of the carbon dioxide recovery apparatus 10D of (3) to (6), further comprising a wash water circulation line 105 that circulates wash water used to wash the absorbent liquid L2 in the absorption tower 12 to the upper part of the absorption tower 12, and a third heat exchanger 43 provided in the wash water circulation line 105 for cooling the wash water, wherein the heating unit 20D heats the heat transfer medium supplied to the first heat exchanger 41 with waste heat obtained by cooling the wash water in the third heat exchanger 43.

[0111] As a result, the third heat exchanger 43 cools the wash water that is circulated to the upper part of the absorption tower 12. The heating unit 20D uses the waste heat obtained by cooling the wash water in the third heat exchanger 43 to heat the heat transfer medium, thereby effectively utilizing the waste heat from the wash water obtained in the third heat exchanger 43.

[0112] (8) The carbon dioxide recovery apparatus 10E according to the eighth embodiment is any one of the carbon dioxide recovery apparatus 10E from (3) to (7), further comprising: an absorbent liquid supply line 106A that supplies the absorbent liquid L2 regenerated in the regeneration tower 13 to the absorption tower 12; and a fourth heat exchanger 46 provided in the absorbent liquid supply line 106A for cooling the absorbent liquid L2, wherein the heating unit 20E heats the heat transfer medium supplied to the first heat exchanger 41 with waste heat obtained by cooling the absorbent liquid L2 in the fourth heat exchanger 46.

[0113] As a result, the fourth heat exchanger 46 cools the absorbent liquid L2 that has been regenerated in the regeneration tower 13. The heating unit 20E heats the heat transfer medium using the waste heat obtained by cooling the absorbent liquid L2 in the fourth heat exchanger 46, thereby effectively utilizing the waste heat from the absorbent liquid L2 obtained in the fourth heat exchanger 46.

[0114] (9) The carbon dioxide recovery device 10F according to the ninth embodiment is any one of the carbon dioxide recovery devices 10F from (3) to (8), further comprising a gaseous carbon dioxide discharge line 109 for discharging gaseous carbon dioxide separated in the regeneration tower 13 from the regeneration tower 13, and a fifth heat exchanger 49 provided in the gaseous carbon dioxide discharge line 109 for cooling the gaseous carbon dioxide, wherein the heating unit 20F heats the heat transfer medium supplied to the first heat exchanger 41 with waste heat obtained by cooling the gaseous carbon dioxide in the fifth heat exchanger 49.

[0115] As a result, the fifth heat exchanger 49 cools the gaseous carbon dioxide separated in the regeneration tower 13. The heating unit 20F heats the heat transfer medium with the waste heat obtained by cooling the gaseous carbon dioxide in the fifth heat exchanger 49, thereby effectively utilizing the waste heat of the absorbent liquid L2 obtained in the fifth heat exchanger 49.

[0116] (10) The carbon dioxide recovery device 10G according to the tenth embodiment is any one of the carbon dioxide recovery devices 10G from (1) to (9), further comprising a desulfurization device 301 that removes sulfur contained in the gas sent through the gas introduction line 101, and a heat recovery device 302 provided upstream of the desulfurization device 301 in the gas flow direction and recovering heat from the gas, wherein the heating unit 20G heats the heat medium supplied to the first heat exchanger 41 with the heat recovered by the heat recovery device 302.

[0117] As a result, the gas temperature may remain high in the heat recovery unit 302, which is located upstream of the desulfurization unit 301 in the gas flow direction. In such cases, the heat recovered in the heat recovery unit 302 can be used to heat the gas sent to the absorption tower 12, thereby increasing the temperature of the gas sent to the absorption tower 12. Therefore, the carbon dioxide absorption efficiency in the absorption tower 12 can be increased.

[0118] (11) The carbon dioxide recovery device 10B according to the eleventh embodiment is any one of the carbon dioxide recovery devices 10B from (1) to (10), further comprising: an inlet temperature detection unit 201 for detecting the inlet temperature of the gas supplied through the gas introduction line 101; and a control device 60 for controlling the heating unit 20B based on the inlet temperature of the gas detected by the inlet temperature detection unit 201.

[0119] As a result, the control device 60 controls the heating unit 20B based on the inlet temperature of the gas supplied through the gas introduction line 101, thereby automatically increasing the carbon dioxide absorption efficiency according to the gas inlet temperature, even when the gas supplied to the carbon dioxide recovery device 10B is at a low temperature.

[0120] (12) The carbon dioxide recovery device 10B according to the twelfth embodiment is the carbon dioxide recovery device 10B of (11), wherein the control device 60 heats the gas sent to the absorption tower 12 in the heating unit 20B when the gas inlet temperature is lower than a preset reference temperature.

[0121] As a result, when the gas inlet temperature in the control device 60 is within a preset range, the heating unit 20B heats the gas sent to the absorption tower 12, thereby automatically increasing the carbon dioxide absorption efficiency when the gas sent to the carbon dioxide recovery device 10B is at a low temperature.

[0122] (13) A carbon dioxide recovery device 10B according to the 13th embodiment is a carbon dioxide recovery device 10B according to (11) or (12), further comprising: a first outlet temperature detection unit 202 for detecting the temperature of the gas at the outlet of the scrubbing tower 11; a second outlet temperature detection unit 203 for detecting the temperature of the gas at the outlet of the absorption tower 12; and a supply line 210 for supplying makeup water to the scrubbing tower 11, wherein the control device 60 controls the heating unit 20B such that the difference between the temperature of the gas detected by the first outlet temperature detection unit 202 and the temperature of the gas detected by the second outlet temperature detection unit 203 is within a preset range.

[0123] As a result, the control device 60 controls the heating unit 20B so that the difference between the gas temperature at the outlet of the scrubbing tower 11, detected by the first outlet temperature detection unit 202, and the gas temperature at the outlet of the absorption tower 12, detected by the second outlet temperature detection unit 203, falls within a preset range. Consequently, the inlet temperature of the gas sent to the carbon dioxide recovery device 10B through the gas introduction line 101 becomes relatively lower than the gas temperature at the outlet of the scrubbing tower 11 and the gas temperature at the outlet of the absorption tower 12. When the gas temperature is lower, the amount of water contained in the gas decreases. Therefore, by supplying makeup water to the scrubbing tower 11 via the replenishment line 210, the lack of water in the scrubbing tower 11 can be compensated for. This prevents the mass balance of the absorbent liquid L2 within the carbon dioxide recovery device 10B system from being disrupted. When supplying makeup water to the scrubbing tower 11, factory water or the like can be used as makeup water, thus suppressing an increase in the operating costs of the carbon dioxide recovery device 10B.

[0124] (14) Operating methods S10, S20 for carbon dioxide recovery devices 10A to 10G according to the 14th embodiment are operating methods S10, S20 for carbon dioxide recovery devices 10A to 10G according to any one of (1) to (13), comprising: steps S11, S21 for detecting the inlet temperature of the gas sent through the gas introduction line 101; and steps S13, S23 for heating the gas sent to the absorption tower 12 in the heating section 20A to 20G when the inlet temperature of the gas is within a preset range.

[0125] In the operating methods S10 and S20 of the carbon dioxide capture devices 10A to 10G, the temperature of the gas supplied to the absorption tower 12 can be increased when the gas supplied to the carbon dioxide capture devices 10A to 10G is within a preset range. Therefore, even when the gas supplied to the carbon dioxide capture devices 10A to 10G is at a low temperature, the carbon dioxide absorption efficiency can be increased. [Explanation of Symbols]

[0126] 10A~10G...Carbon dioxide capture device 11... Washing Tower 11a...Tower body 11b…Nozzle 12… Absorption tower 12a... Tower body 12b, 12c... nozzles 12d... Washing water receiver 12e... Exhaust pipe 13…Regeneration Tower 13a... Tower body 13b, 13c… Nozzles 15…Recovery Department 20A~20G…Heating part 21…Heat source 31…Cleaning fluid supply pump 32A...First circulation pump 32B...Second circulation pump 33... Absorption fluid circulation pump 41...First heat exchanger 43…Third heat exchanger 45...Heat exchanger 46…Fourth heat exchanger 48… Reboiler (second heat exchanger) 49...Condenser (Fifth Heat Exchanger) 60...Control device 61… Processor 62...ROM 63...RAM 64... Storage 65…Signal transmission and reception module 70...Signal input section 71…Information acquisition department 72... Valve control unit 75…Output section 81... Steam supply pipe 82A~82C…Cooling water supply pipe 101...Gas introduction line 102... Cleaning fluid supply line 103...Gas discharge line 104A... Refrigerant supply line 104B... Refrigerant discharge line 104V, 104W... Shut-off valve 105... Wash water circulation line 106... Circulation line 106A... Absorbent liquid supply line 106B... Absorbent liquid discharge line 107…Media Line 108... Absorbent liquid heating line 109…Gaseous carbon dioxide emission line 110... Circulation line 111... Carbon dioxide emission pipe 112...Reflux pump 121, 121C~121G... Heat transfer fluid recovery line 121V... Shut-off valve 122, 122C~122G…heat medium supply line 122V... Shut-off valve 122W... Flow control valve 201... Inlet temperature detection unit 202...First outlet temperature detection unit 203...Second outlet temperature detection unit 210... Supply Line 301...Desulfurization equipment 302... Heat recovery device L1…Cleaning solution L2…Absorbent liquid

Claims

1. A gas introduction line into which gas containing carbon dioxide is supplied from an external source, A washing tower that washes the gas by bringing the gas supplied to the gas introduction line into contact with a washing solution, An absorption tower is provided, into which an absorbent liquid capable of absorbing carbon dioxide in the gas is introduced, and the absorbent liquid absorbs the carbon dioxide in the gas that has passed through the gas scrubbing tower. A regeneration tower that heats the absorbent liquid that has absorbed carbon dioxide, separates carbon dioxide from the absorbent liquid, and regenerates the absorbent liquid, The system includes a heating unit for heating the gas supplied to the absorption tower. Carbon dioxide capture device.

2. The heating unit heats the gas when the gas temperature is lower than a preset reference temperature. The carbon dioxide recovery apparatus according to claim 1.

3. A cleaning liquid supply line connected to the aforementioned cleaning tower and supplying the cleaning liquid to the cleaning tower, The cleaning fluid supply line further comprises a first heat exchanger, The heating section is The first heat exchanger is supplied with a heat transfer medium at a higher temperature than the cleaning liquid, and the cleaning liquid is heated by heat exchange between the heat transfer medium and the cleaning liquid. A carbon dioxide recovery device according to claim 1 or 2.

4. The first heat exchanger cools the cleaning solution by exchanging heat between the cleaning solution and a refrigerant at a lower temperature when the gas temperature is above a preset reference temperature. The carbon dioxide recovery apparatus according to claim 3.

5. The heating unit includes a heat source for heating the heat transfer medium. The carbon dioxide recovery apparatus according to claim 3.

6. The regeneration tower further comprises a second heat exchanger that heats the absorbent liquid supplied to the regeneration tower with steam supplied from an external source. The heating unit supplies the steam that has passed through the second heat exchanger to the first heat exchanger as the heat transfer medium. The carbon dioxide recovery apparatus according to claim 3.

7. A washing water circulation line that circulates the washing water used to wash the absorbent liquid in the absorption tower to the upper part of the absorption tower, The wash water circulation line further includes a third heat exchanger for cooling the wash water, The heating unit heats the heat transfer medium supplied to the first heat exchanger using the waste heat obtained by cooling the washing water in the third heat exchanger. The carbon dioxide recovery apparatus according to claim 3.

8. An absorption liquid supply line for supplying the absorption liquid regenerated in the regeneration tower to the absorption tower, The absorbent liquid supply line is further provided with a fourth heat exchanger for cooling the absorbent liquid, The heating unit heats the heat transfer medium supplied to the first heat exchanger using the waste heat obtained by cooling the absorbent liquid in the fourth heat exchanger. The carbon dioxide recovery apparatus according to claim 3.

9. A gaseous carbon dioxide discharge line for discharging gaseous carbon dioxide separated in the regeneration tower from the regeneration tower, The gaseous carbon dioxide discharge line further comprises a fifth heat exchanger provided in the gaseous carbon dioxide discharge line for cooling the gaseous carbon dioxide, The heating unit heats the heat transfer medium supplied to the first heat exchanger using the waste heat obtained by cooling the carbon dioxide gas in the fifth heat exchanger. The carbon dioxide recovery apparatus according to claim 3.

10. A desulfurization apparatus that removes sulfur from the gas supplied through the gas introduction line, The system further comprises a heat recovery device provided upstream of the desulfurization device in the gas flow direction, which recovers heat from the gas, The heating section is The heat recovered by the heat recovery device heats the heat transfer medium supplied to the first heat exchanger. The carbon dioxide recovery apparatus according to claim 3.

11. An inlet temperature detection unit for detecting the inlet temperature of the gas supplied through the gas introduction line, The system further comprises a control device that controls the heating unit based on the gas inlet temperature detected by the inlet temperature detection unit. A carbon dioxide recovery device according to claim 1 or 2.

12. The control device heats the gas supplied to the absorption tower in the heating unit when the gas inlet temperature is lower than a preset reference temperature. The carbon dioxide recovery apparatus according to claim 11.

13. A first outlet temperature detection unit for detecting the temperature of the gas at the outlet of the washing tower, A second outlet temperature detection unit for detecting the temperature of the gas at the outlet of the absorption tower, The aforementioned scrubbing tower is further provided with a supply line for supplying makeup water, The control device controls the heating unit so that the difference between the gas temperature detected by the first outlet temperature detection unit and the gas temperature detected by the second outlet temperature detection unit falls within a preset range. The carbon dioxide recovery apparatus according to claim 11.

14. A method for operating a carbon dioxide recovery apparatus according to claim 1 or 2, The steps include detecting the inlet temperature of the gas supplied through the gas introduction line, The step includes heating the gas being supplied to the absorption tower in the heating unit when the gas inlet temperature is within a preset range. Operating instructions for a carbon dioxide capture system.

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