Carbon Dioxide Recovery System and Method for Operating the Carbon Dioxide Recovery System

Abstract

The present invention relates to a carbon dioxide recovery system and an operation method of the carbon dioxide recovery system. The carbon dioxide recovery system according to an embodiment includes a carbon dioxide recovery unit, an absorbent regeneration unit, a first cleaning unit, a second cleaning unit, and an absorbent pipeline. The first cleaning unit cleans the combustion exhaust gas discharged from the carbon dioxide recovery unit with the mist of the first cleaning liquid ejected by the first ejector, and recovers the amine accompanying the combustion exhaust gas. The absorbent pipeline supplies the absorbent regenerated in the absorbent regeneration unit to the first ejector as the first cleaning liquid. The first cleaning liquid ejected by the first ejector is supplied to the carbon dioxide recovery unit as the absorbent.

Description

Technical Field

[0001] Embodiments of the present invention relate to a carbon dioxide recovery system and an operation method of the carbon dioxide recovery system. Background Art

[0002] In recent years, as one of the causes of global warming, the greenhouse effect of carbon dioxide contained in the combustion exhaust gas generated when fossil fuels are burned has been pointed out.

[0003] Under such circumstances, a carbon dioxide recovery system for suppressing the discharge of carbon dioxide contained in the combustion exhaust gas generated by burning fossil fuels into the atmosphere has been studied in thermal power plants and the like that use a large amount of fossil fuels. In the carbon dioxide recovery system, the combustion exhaust gas is brought into contact with an amine-based absorbent liquid, and carbon dioxide is separated from the combustion exhaust gas and recovered.

[0004] More specifically, the carbon dioxide recovery system includes an absorption tower and a regeneration tower. The absorption tower is configured to absorb carbon dioxide contained in the combustion exhaust gas into the amine-based absorbent liquid. The absorbent liquid that has absorbed carbon dioxide (rich solution) is supplied from the absorption tower to the regeneration tower. In the regeneration tower, the supplied rich solution is heated to release carbon dioxide from the rich solution, and at the same time, the absorbent liquid is regenerated. A reboiler for supplying a heat source is connected to the regeneration tower, and the rich solution is heated inside the regeneration tower. The absorbent liquid that has been regenerated in the regeneration tower (lean solution) is supplied to the absorption tower, and the absorbent liquid is circulated in the system.

[0005] However, in such a carbon dioxide recovery system, there is a problem associated with amines when the combustion exhaust gas (carbon dioxide-removed combustion exhaust gas) in which carbon dioxide has been absorbed into the amine-based absorbent liquid is discharged from the absorption tower to the atmosphere. That is, since a large amount of combustion exhaust gas is released in thermal power plants and the like, it is possible that a large amount of amino compounds (amines) are released along with the carbon dioxide-removed combustion exhaust gas. On the other hand, there is also a problem associated with amines when discharging the carbon dioxide-containing gas containing carbon dioxide from the regeneration tower. Therefore, when using a carbon dioxide recovery system in a thermal power plant, it is desired to effectively reduce the amines discharged from the carbon dioxide recovery system. Summary of the Invention

[0006] The carbon dioxide recovery system based on the embodiment includes a carbon dioxide recovery section, an absorbent regeneration section, a first cleaning section, a second cleaning section, and an absorbent pipeline. The carbon dioxide recovery section absorbs the carbon dioxide contained in the combustion exhaust gas into an absorbent containing amine. The absorbent regeneration section regenerates the absorbent by releasing carbon dioxide from the absorbent discharged from the carbon dioxide recovery section. The first cleaning section cleans the combustion exhaust gas discharged from the carbon dioxide recovery section with the mist of the first cleaning liquid ejected by the first ejector, and recovers the amine accompanying the combustion exhaust gas; the second cleaning section cleans the combustion exhaust gas discharged from the first cleaning section with the second cleaning liquid, and recovers the amine accompanying the combustion exhaust gas. The absorbent pipeline supplies the absorbent regenerated in the absorbent regeneration section to the first ejector as the first cleaning liquid. The first cleaning liquid ejected by the first ejector is supplied to the carbon dioxide recovery section as the absorbent.

[0007] The carbon dioxide recovery system based on the embodiment includes a carbon dioxide recovery section, an absorbent regeneration section, and a regeneration cleaning section. The carbon dioxide recovery section absorbs the carbon dioxide contained in the combustion exhaust gas into an absorbent containing amine. The absorbent regeneration section releases the carbon dioxide from the absorbent discharged from the carbon dioxide recovery section, discharges the regenerated exhaust gas containing carbon dioxide, and at the same time regenerates the absorbent. The regeneration cleaning section cleans the regenerated exhaust gas discharged from the absorbent regeneration section with the mist of the regeneration cleaning liquid ejected by the regeneration ejector, and recovers the amine accompanying the regenerated exhaust gas.

[0008] The operation method of the carbon dioxide recovery system based on the embodiment includes a step of absorbing the carbon dioxide contained in the combustion exhaust gas into an absorbent containing amine in the carbon dioxide recovery section. The operation method includes a step of regenerating the absorbent by releasing carbon dioxide from the absorbent discharged from the carbon dioxide recovery section. The operation method includes a step of cleaning the combustion exhaust gas discharged from the carbon dioxide recovery section with the mist of the first cleaning liquid ejected from the ejector in the first cleaning section, and recovering the amine accompanying the combustion exhaust gas. The operation method includes a step of cleaning the combustion exhaust gas discharged from the first cleaning section with the second cleaning liquid, and recovering the amine accompanying the combustion exhaust gas. The absorbent regenerated in the step of regenerating the absorbent is supplied to the first ejector as the first cleaning liquid. The first cleaning liquid ejected by the first ejector is supplied to the carbon dioxide recovery section as the absorbent.

[0009] The operation method of the carbon dioxide recovery system according to the embodiment includes a step of absorbing carbon dioxide contained in the combustion exhaust gas into an absorption liquid containing amine in the carbon dioxide recovery section. The operation method includes a step of regenerating the absorption liquid in the absorption liquid regeneration section by releasing carbon dioxide from the absorption liquid discharged from the carbon dioxide recovery section, discharging the regenerated exhaust gas containing the carbon dioxide, and regenerating the absorption liquid. The operation method includes a step of cleaning the regenerated exhaust gas discharged from the absorption liquid regeneration section with a mist of the regenerated cleaning liquid ejected from the regenerated ejector in the regenerated cleaning section, and recovering the amine accompanying the regenerated exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the first embodiment of the present invention.

[0011] Figure 2 It shows Figure 1 a graph showing the relationship between the flow rate of the first cleaning liquid and the removal rate of the amine in the form of mist in the carbon dioxide recovery system shown.

[0012] Figure 3 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the second embodiment of the present invention.

[0013] Figure 4 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the third embodiment of the present invention.

[0014] Figure 5 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the fourth embodiment of the present invention.

[0015] Figure 6 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the fifth embodiment of the present invention.

[0016] Figure 7 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the sixth embodiment of the present invention.

[0017] Figure 8 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the seventh embodiment of the present invention.

[0018] Figure 9 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the eighth embodiment of the present invention.

[0019] Figure 10 FIG. is a diagram showing the overall configuration of the carbon dioxide recovery system according to the ninth embodiment of the present invention.

[0020] Figure 11This is a diagram showing the overall configuration of the carbon dioxide recovery system in the 10th embodiment of the present invention. Detailed Embodiment

[0021] Hereinafter, the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] (First Embodiment)

[0023] First, use Figure 1 and Figure 2 to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the first embodiment of the present invention.

[0024] As Figure 1 shown, the carbon dioxide recovery system 1 includes an absorption tower 20 that absorbs carbon dioxide contained in the combustion exhaust gas 2 into an absorption liquid containing amine, and a regeneration tower 30 that releases carbon dioxide from the absorption liquid discharged from the absorption tower 20 to regenerate the absorption liquid. The combustion exhaust gas 2 in which carbon dioxide has been absorbed into the absorption liquid in the absorption tower 20 is discharged from the absorption tower 20 as decarbonized combustion exhaust gas 3 (described later). In addition, a carbon dioxide-containing gas 8 (regenerated exhaust gas) containing carbon dioxide is discharged from the regeneration tower 30. It should be noted that the combustion exhaust gas 2 supplied to the absorption tower 20 is not particularly limited, but for example, it can be the combustion exhaust gas of a boiler (not shown) of a thermal power plant, process exhaust gas, etc., and can also be supplied to the absorption tower 20 after cooling treatment as needed.

[0025] The absorption liquid circulates between the absorption tower 20 and the regeneration tower 30. The absorption liquid absorbs carbon dioxide in the absorption tower 20 and becomes a rich solution 4, and releases carbon dioxide in the regeneration tower 30 and becomes a lean solution 5. The absorption tower 20 and the regeneration tower 30 are connected by a rich solution pipeline 15 and a lean solution pipeline 16. The rich solution pipeline 15 supplies the rich solution 4 discharged from the absorption tower 20 to the regeneration tower 30. The lean solution pipeline 16 (absorption liquid pipeline) supplies the lean solution 5 discharged from the regeneration tower 30 to the first ejector 21b of the absorption tower 20.

[0026] There is no particular limitation on the absorption liquid, but for example, alcohol-containing hydroxyl primary amines such as monoethanolamine and 2-amino-2-methyl-1-propanol, alcohol-containing hydroxyl secondary amines such as diethanolamine and 2-methylaminoethanol, alcohol-containing hydroxyl tertiary amines such as triethanolamine and N-methyldiethanolamine, polyethylenepolyamines such as ethylenediamine, triethylenediamine, and diethylenetriamine, cyclic amines such as piperazine, piperidine, and pyrrolidine, polyamines such as benzyldimethyldiamine, amino acids such as methylaminocarboxylic acid, etc., and mixtures thereof can be used. These amine compounds are usually used in the form of an aqueous solution containing 10 to 70% by weight. In addition, a carbon dioxide absorption promoter or a corrosion inhibitor, and further methanol, polyethylene glycol, sulfolane, etc. as other media can be added to the absorption liquid.

[0027] The absorption tower 20 has a carbon dioxide recovery section 20a and an absorption tower container 20c that houses the carbon dioxide recovery section 20a.

[0028] The carbon dioxide recovery section 20a is configured in the form of a countercurrent gas-liquid contact device. As an example, the carbon dioxide recovery section 20a includes a carbon dioxide recovery packing layer 20d. The carbon dioxide recovery packing layer 20d is composed of internal structures such as fillers and particles filled inside for increasing the gas-liquid contact area. On the surface of this internal structure, the lean solution 5 supplied from the regeneration tower 30 flows down while making gas-liquid contact with the carbon dioxide contained in the combustion exhaust gas 2, and the carbon dioxide is absorbed into the lean solution 5. Thus, the carbon dioxide is recovered (or removed) from the combustion exhaust gas 2.

[0029] In the present embodiment, a liquid disperser 20b shown in the following Figure 3 etc. is not provided. In the carbon dioxide recovery section 20a, the lean solution 5 is supplied from a first ejector 21b described later. The first ejector 21b is connected to the above-mentioned lean solution pipeline 16, and the lean solution 5 as the first cleaning liquid 11 is supplied to the first ejector 21b. That is, the first cleaning liquid 11 ejected from the first ejector 21b is composed of the lean solution 5. By ejecting the first cleaning liquid 11 from the first ejector 21b, the mist of the first cleaning liquid 11 is dispersed and falls toward the carbon dioxide recovery section 20a. The first cleaning liquid 11 that has reached the carbon dioxide recovery section 20a is supplied as the lean solution 5 to the surface of the internal structure of the carbon dioxide recovery packing layer 20d. The pressure of the lean solution 5 supplied to the first ejector 21b is increased by a lean solution pump 34.

[0030] In the absorption tower container 20c, there are accommodated a carbon dioxide recovery packing layer 20d, a first cleaning section 21, a second cleaning section 22, and mist eliminators 81 and 82 which will be described later. The absorption tower container 20c is configured to receive the combustion exhaust gas 2 from the lower part of the absorption tower container 20c and discharge the combustion exhaust gas 2 from the top of the absorption tower container 20c as the de-carbonated combustion exhaust gas 3 which will be described later.

[0031] In the lower part of the absorption tower 20, the combustion exhaust gas 2 containing carbon dioxide discharged from the outside of the carbon dioxide recovery system 1 such as the above-mentioned boiler (not shown) is supplied by a blower. The supplied combustion exhaust gas 2 rises in the absorption tower 20 toward the carbon dioxide recovery packing layer 20d of the carbon dioxide recovery section 20a. On the other hand, the lean solution 5 from the regeneration tower 30 is ejected from the first ejector 21b. Thus, the mist of the lean solution 5 falls and is supplied to the carbon dioxide recovery packing layer 20d. Therefore, the lean solution 5 flows down on the surface of the internal structure in the carbon dioxide recovery packing layer 20d. In the carbon dioxide recovery packing layer 20d, the combustion exhaust gas 2 and the lean solution 5 are in gas-liquid contact, and the carbon dioxide contained in the combustion exhaust gas 2 is absorbed into the lean solution 5 to generate a rich solution 4.

[0032] The generated rich solution 4 is temporarily stored in the lower part of the absorption tower container 20c and is discharged from this lower part to the rich solution pipeline 15. The carbon dioxide in the combustion exhaust gas 2 after gas-liquid contact with the lean solution 5 is removed, and the de-carbonated combustion exhaust gas 3 further rises in the absorption tower 20 from the carbon dioxide recovery packing layer 20d.

[0033] A heat exchanger 31 is provided between the absorption tower 20 and the regeneration tower 30. On the heat exchanger 31, the above-mentioned rich solution pipeline 15 and lean solution pipeline 16 pass through. A rich solution pump 32 is provided on the rich solution pipeline 15, and the rich solution 4 discharged from the absorption tower 20 is supplied to the regeneration tower 30 through the heat exchanger 31 by the rich solution pump 32. The heat exchanger 31 exchanges heat between the rich solution 4 supplied from the absorption tower 20 to the regeneration tower 30 and the lean solution 5 supplied from the regeneration tower 30 to the absorption tower 20. Thus, the lean solution 5 becomes a heat source, and the rich solution 4 is heated to a desired temperature. In other words, the rich solution 4 becomes a cold heat source, and the lean solution 5 is cooled to a desired temperature.

[0034] The regeneration tower 30 has an amine regeneration section 30a (absorbent regeneration section), a liquid distributor 30b provided above the amine regeneration section 30a, and a regeneration tower container 30c that houses the amine regeneration section 30a and the liquid distributor 30b.

[0035] The amine regeneration section 30a is configured in the form of a countercurrent gas-liquid contact device. As an example, the amine regeneration section 30a includes an amine regeneration packed bed 30d. The amine regeneration packed bed 30d is composed of internal structures such as fillers and particles filled inside for increasing the gas-liquid contact area. On the surface of this internal structure, the rich solution 4 supplied from the absorption tower 20 flows down while making gas-liquid contact with the vapor 7 described later, and carbon dioxide is released from the rich solution 4. Thus, carbon dioxide is recovered (or removed) from the rich solution 4.

[0036] The liquid distributor 30b is configured to disperse and drop the rich solution 4 toward the amine regeneration section 30a. The rich solution 4 is supplied to the surface of the internal structure of the amine regeneration packed bed 30d. The pressure of the rich solution 4 supplied to the liquid distributor 30b is not so high relative to the pressure inside the regeneration tower 30, and the liquid distributor 30b is not substantially forced, and mainly due to the action of gravity, the rich solution 4 drops toward the amine regeneration section 30a.

[0037] In the regeneration tower container 30c, the amine regeneration packed bed 30d, the liquid distributor 30b, the regeneration cleaning section 37 described later, and the demisters 86 and 87 are accommodated. The regeneration tower container 30c is configured to discharge the carbon dioxide-containing gas 8 released from the rich solution 4 from the top of the regeneration tower container 30c.

[0038] A reboiler 33 is connected to the regeneration tower 30. The reboiler 33 heats the lean solution 5 supplied from the regeneration tower 30 by a heating medium 6 to generate a vapor 7, and supplies the generated vapor 7 to the regeneration tower 30. More specifically, for the reboiler 33, a part of the lean solution 5 discharged from the lower part of the regeneration tower 30 is supplied, and at the same time, a high-temperature vapor as the heating medium 6 is supplied from the outside such as a turbine (not shown). The lean solution 5 supplied to the reboiler 33 is heated by heat exchange with the heating medium 6, and the vapor 7 is generated from the lean solution 5. The generated vapor 7 is supplied to the lower part of the regeneration tower 30 to heat the lean solution 5 inside the regeneration tower 30. It should be noted that the heating medium 6 supplied to the reboiler 33 is not limited to the high-temperature vapor from the turbine.

[0039] At the lower part of the regeneration tower 30, the vapor 7 is supplied from the reboiler 33 and rises inside the regeneration tower 30 toward the amine regeneration packed bed 30d of the amine regeneration section 30a. On the other hand, the rich solution 4 from the absorption tower 20 is supplied to the liquid distributor 30b and drops, and is supplied to the amine regeneration packed bed 30d and flows down on the surface of its internal structure. In the amine regeneration packed bed 30d, the rich solution 4 makes gas-liquid contact with the vapor 7, and carbon dioxide gas is released from the rich solution 4 to generate the lean solution 5. In this way, the absorption liquid is regenerated in the regeneration tower 30.

[0040] The generated lean solution 5 is discharged from the lower part of the regeneration tower 30. The vapor 7 after gas-liquid contact with the rich solution 4 contains carbon dioxide and is discharged from the top of the regeneration tower 30 as carbon dioxide-containing gas 8. The discharged carbon dioxide-containing gas 8 also contains vapor.

[0041] A lean solution pump 34 is provided on the lean solution pipeline 16. The lean solution 5 discharged from the regeneration tower 30 is supplied to the absorption tower 20 through the lean solution pump 34 via the heat exchanger 31 described above. The heat exchanger 31 cools the lean solution 5 supplied from the regeneration tower 30 to the absorption tower 20 by heat-exchanging it with the rich solution 4 supplied from the absorption tower 20 to the regeneration tower 30 as described above. In addition, on the lean solution pipeline 16, a lean solution cooler 35 (absorption liquid cooler) for cooling the lean solution 5 supplied from the regeneration tower 30 to the carbon dioxide recovery section 20a is provided. The lean solution cooler 35 is supplied with a cooling medium such as cooling water from the outside (e.g., cooling water of a cooling tower, seawater) and further cools the lean solution 5 cooled in the heat exchanger 31 to a desired temperature.

[0042] The lean solution 5 cooled in the lean solution cooler 35 is supplied as the first cleaning liquid 11 to the first ejector 21b of the absorption tower 20. The mist of the first cleaning liquid 11 falls from the first ejector 21b and passes through the first cleaning recovery space 21a described later. The mist of the first cleaning liquid 11 is supplied as the lean solution 5 to the carbon dioxide recovery packing layer 20d of the carbon dioxide recovery section 20a and flows down on the surface of the internal structure therein. In the carbon dioxide recovery packing layer 20d, the lean solution 5 makes gas-liquid contact with the combustion exhaust gas 2. Thereby, by absorbing the carbon dioxide contained in the combustion exhaust gas 2, the lean solution 5 becomes the rich solution 4. By operating in this way, in the carbon dioxide recovery system 1, the absorption liquid circulates while repeatedly changing between the state of the lean solution 5 and the state of the rich solution 4.

[0043] Figure 1 The carbon dioxide recovery system 1 shown further includes a gas cooler 40 for cooling the carbon dioxide-containing gas 8 discharged from the top of the regeneration tower 30 and condensing the vapor to generate condensed water 9, and a gas-liquid separator 41 for separating the condensed water 9 generated by the gas cooler 40 from the carbon dioxide-containing gas 8. By operating in this way, the moisture content in the carbon dioxide-containing gas 8 is reduced, and the carbon dioxide-containing gas 8 is discharged from the gas-liquid separator 41 as carbon dioxide gas 10. The discharged carbon dioxide gas 10 is supplied to an unillustrated device and stored. On the other hand, the condensed water 9 separated in the gas-liquid separator 41 is supplied to the regeneration tower 30 by a condensed water pump 42 and mixed into the absorption liquid. It should be noted that for the gas cooler 40, a cooling medium (e.g., cooling water of a cooling tower, seawater) for cooling the carbon dioxide-containing gas 8 is supplied from the outside.

[0044] Incidentally, in the absorption tower 20, a first cleaning unit 21 and a second cleaning unit 22 are accommodated. The first cleaning unit 21 cleans the de-carbonated combustion exhaust gas 3 discharged from the carbon dioxide recovery unit 20a with the mist of the first cleaning liquid 11, and recovers the amine, which is the absorption liquid component accompanying the de-carbonated combustion exhaust gas 3. The first cleaning unit 21 is provided above the carbon dioxide recovery unit 20a.

[0045] The first cleaning unit 21 has a first cleaning and recovery space 21a and a first ejector 21b provided above the first cleaning and recovery space 21a.

[0046] The first cleaning and recovery space 21a is a space provided below the first ejector 21b. The first cleaning and recovery space 21a of the present embodiment is a space provided across the carbon dioxide recovery unit 20a from the first ejector 21b. In the first cleaning and recovery space 21a, the first cleaning liquid 11 is ejected from the first ejector 21b. The ejected first cleaning liquid 11 falls freely in the first cleaning and recovery space 21a in a mist state (i.e., falls without contacting the surface of structures in the space) and contacts the rising de-carbonated combustion exhaust gas 3. Thereby, the amine accompanying the de-carbonated combustion exhaust gas 3 is recovered. In the first cleaning unit 21, mist-like amine can be effectively recovered, but gaseous amine can also be effectively recovered.

[0047] In the present embodiment, as described above, a first cleaning and recovery space 21a is formed between the first ejector 21b and the carbon dioxide recovery unit 20a. In the first cleaning and recovery space 21a, structures such as a packing layer or a tray for allowing the first cleaning liquid 11 to flow on the surface and contact the de-carbonated combustion exhaust gas 3 are not provided. The first ejector 21b faces the carbon dioxide recovery unit 20a across the first cleaning and recovery space 21a. That is, between the first ejector 21b and the carbon dioxide recovery unit 20a, structures such as those for the first cleaning liquid 11 to flow on the surface are not provided, and the first cleaning and recovery space 21a is formed across the carbon dioxide recovery unit 20a from the first ejector 21b. Thus, the first cleaning and recovery space 21a is configured such that the first cleaning liquid 11 falls freely and contacts the de-carbonated combustion exhaust gas 3. The mist of the first cleaning liquid 11 ejected from the first ejector 21b falls in the first cleaning and recovery space 21a where the de-carbonated combustion exhaust gas 3 rises and directly reaches the carbon dioxide recovery unit 20a. That is, the first cleaning liquid 11 after passing through the first cleaning and recovery space 21a directly reaches the carbon dioxide recovery unit 20a. During the falling process, the first cleaning liquid 11 contacts the de-carbonated combustion exhaust gas 3, and the mist-like amine accompanying the de-carbonated combustion exhaust gas 3 is physically collided with the mist of the first cleaning liquid 11 and recovered.

[0048] The first injector 21b sprays the first cleaning liquid 11 toward the first cleaning and recovery space 21a so that it falls. The first injector 21b includes a plurality of spray nozzle holes (not shown), and the supplied first cleaning liquid 11 is sprayed (atomized) from the spray nozzle holes by increasing the pressure with a first circulation pump 51 described later. As a result, the first cleaning liquid 11 becomes atomized and is sprayed at high speed from the injector 21b, and freely falls while evenly spreading in the first cleaning and recovery space 21a. That is, the first injector 21b gives the first cleaning liquid 11 a first vertical initial velocity as a velocity component in the vertical direction, so that it has a velocity component in the vertical direction in the first cleaning and recovery space 21a and is forced to freely fall (spray).

[0049] In the present embodiment, a first receiving portion 21c as shown in the following Figure 3 etc. is not provided. The first injector 21b faces the carbon dioxide recovery portion 20a across the first cleaning and recovery space 21a. The mist of the first cleaning liquid 11 sprayed from the first injector 21b falls in the first cleaning and recovery space 21a and reaches the carbon dioxide recovery portion 20a.

[0050] The second cleaning portion 22 cleans the de-carbonated combustion exhaust gas 3 discharged from the first cleaning portion 21 with a second cleaning liquid 12 (or second cleaning water), and recovers the amine accompanying the de-carbonated combustion exhaust gas 3. The second cleaning portion 22 is provided above the first cleaning portion 21.

[0051] The second cleaning portion 22 includes a cleaning and recovery portion 22a, a cleaning liquid disperser 22b provided above the cleaning and recovery portion 22a, and a second receiving portion 22c provided below the cleaning and recovery portion 22a.

[0052] The cleaning and recovery portion 22a is configured in the form of a countercurrent gas-liquid contact device. As an example, the cleaning and recovery portion 22a includes a cleaning and recovery packing layer 22d. The cleaning and recovery packing layer 22d is composed of internal structures such as fillers and particles filled inside for increasing the gas-liquid contact area. The second cleaning liquid 12 flows down onto the surface of the internal structure while making gas-liquid contact with the de-carbonated combustion exhaust gas 3 to recover (or remove) the amine accompanying the de-carbonated combustion exhaust gas 3. In the second cleaning portion 22, gaseous amine can be effectively recovered, but also mist-like amine can be effectively recovered.

[0053] The cleaning liquid disperser 22b is configured to disperse and drop the second cleaning liquid 12 toward the cleaning and recovery section 22a. The second cleaning liquid 12 is supplied in such a manner as to flow down along the surface of the internal structure in the cleaning and recovery section 22a. The pressure of the second cleaning liquid 12 supplied to the cleaning liquid disperser 22b is lower than the pressure of the first cleaning liquid 11 supplied to the first ejector 21b. The pressure of the second cleaning liquid 12 supplied to the cleaning liquid disperser 22b is a pressure that is not so high relative to the pressure inside the absorption tower 20. The vertical velocity component of the second cleaning liquid 12 imparted by the cleaning liquid disperser 22b, that is, the second initial vertical velocity, is smaller than the vertical velocity component of the first cleaning liquid 11 imparted by the first ejector 21b of the first cleaning section 21, that is, the first initial vertical velocity. Substantially, the second initial vertical velocity imparted to the second cleaning liquid 12 is almost zero (zero), and the cleaning liquid disperser 22b non-forcibly allows the second cleaning liquid 12 to freely fall onto the cleaning and recovery section 22a by the action of gravity.

[0054] The second receiving section 22c is configured to receive and store the second cleaning liquid 12 flowing down along the surface of the internal structure in the cleaning and recovery section 22a, and to allow the de-carbonated combustion exhaust gas 3 that rises and is discharged from the first cleaning and recovery space 21a of the first cleaning section 21 to pass through. That is, the second receiving section 22c is composed of a receiving section main body that receives and stores the second cleaning liquid 12, an opening through which the de-carbonated combustion exhaust gas 3 passes provided between the receiving section main bodies, and a lid that covers the opening from above and is used to suppress the second cleaning liquid 12 from passing through the opening.

[0055] A second circulation pipeline 54 for circulating the second cleaning liquid 12 is connected to the second cleaning section 22. That is, a second circulation pump 55 is provided on the second circulation pipeline 54 to extract and supply the second cleaning liquid 12 stored in the second receiving section 22c to the cleaning liquid disperser 22b. In this way, the second cleaning liquid 12 is circulated.

[0056] In the present embodiment, a second cleaning liquid cooler 56 for cooling the second cleaning liquid 12 is provided on the second circulation pipeline 54. For the second cleaning liquid cooler 56, as a cooling medium for cooling the second cleaning liquid 12, a cooling medium (for example, cooling water of a cooling tower, seawater) is supplied from outside the carbon dioxide recovery system 1. By operating in this way, the second cleaning liquid cooler 56 is configured to cool the second cleaning liquid 12 flowing in the second circulation pipeline 54, and to make the temperature of the second cleaning liquid 12 lower than the temperature of the first cleaning liquid 11. It should be noted that it may also be configured such that the temperature of the second cleaning liquid 12 becomes substantially equal to the temperature of the first cleaning liquid 11.

[0057] A first scrubber outlet demister 81 is provided between the first scrubbing section 21 and the second scrubbing section 22. The first scrubber outlet demister 81 is provided between the first scrubbing section 21 and the second scrubbing section 22 (more specifically, between the first ejector 21b and the second receiving section 22c). Thus, the decarbonated combustion exhaust gas 3 discharged from the first scrubbing section 21 rises through the first scrubber outlet demister 81. The first scrubber outlet demister 81 captures the mist entrained in the passing decarbonated combustion exhaust gas 3. The first scrubber outlet demister 81 can effectively capture the mist of amine in the form of a mist and the mist of the first cleaning liquid 11.

[0058] A second scrubber outlet demister 82 is provided above the second scrubbing section 22. The second scrubber outlet demister 82 is provided above the second scrubbing section 22 (more specifically, between the cleaning liquid disperser 22b and the top of the absorption tower container 20c). Thus, the decarbonated combustion exhaust gas 3 discharged from the second scrubbing section 22 rises through the second scrubber outlet demister 82. The second scrubber outlet demister 82 captures the mist entrained in the passing decarbonated combustion exhaust gas 3. The second scrubber outlet demister 82 can effectively capture the mist of amine in the form of a mist and the mist of the second cleaning liquid 12. In addition, since the second cleaning liquid 12 adheres to the second scrubber outlet demister 82, the second scrubber outlet demister 82 can also capture gaseous amine.

[0059] In the present embodiment, the cleaning and recovery packing layer 22d of the second scrubbing section 22 can be configured in such a way that it can reduce the pressure loss generated by the flow of the passing decarbonated combustion exhaust gas 3 more than the second scrubber outlet demister 82. For example, the porosity of the cleaning and recovery packing layer 22d can be larger than the porosity of the second scrubber outlet demister 82. In other words, the specific surface area of the cleaning and recovery packing layer 22d can be smaller than the specific surface area of the second scrubber outlet demister 82.

[0060] As Figure 1 shown, between the carbon dioxide recovery section 20a and the first scrubbing section 21, no demister is provided. Generally, a demister is often provided between the carbon dioxide recovery section 20a and the first scrubbing section 21. However, in the present embodiment, the first cleaning liquid 11 is composed of the lean solution 5, and the difference in the amine concentration of the lean solution 5 in the carbon dioxide recovery section 20a and the amine concentration of the first cleaning liquid 11 in the first scrubbing section 21 is small. Therefore, for the purpose of reducing the pressure loss of the flow of the decarbonated combustion exhaust gas 3, no demister is provided between the carbon dioxide recovery section 20a and the first scrubbing section 21.

[0061] Incidentally, the flow rate per unit area and unit time (the first flow rate) of the first cleaning liquid 11 ejected from the first ejector 21b of the first cleaning unit 21 becomes larger than the flow rate per unit area and unit time (the second flow rate) of the second cleaning liquid 12 dispersed by the cleaning liquid disperser 22b of the second cleaning unit 22. The flow rate of the first cleaning liquid 11 ejected from the first ejector 21b is adjusted by the above-described first circulation pump 51 (flow rate adjustment unit). Similarly, the flow rate of the second cleaning liquid 12 dispersed by the cleaning liquid disperser 22b is adjusted by the second circulation pump 55.

[0062] It should be noted that the unit area shown here is the unit area with respect to the horizontal cross-sectional area where the first ejector 21b ejects the first cleaning liquid 11 (or the horizontal cross-sectional area of the first cleaning unit 21), and the horizontal cross-sectional area where the cleaning liquid disperser 22b disperses the second cleaning liquid 12 (or the horizontal cross-sectional area of the second cleaning unit 22). In the present embodiment, since the horizontal cross-sectional areas of the first cleaning unit 21 and the second cleaning unit 22 are substantially equal, the difference in the horizontal cross-sectional areas of the respective cleaning units (the first cleaning unit 21 and the second cleaning unit 22) may not be considered, and the first flow rate and the second flow rate may be set by the flow rate per unit time.

[0063] If generalizing to include the case where the horizontal cross-sectional areas of the respective cleaning units 21 and 22 are different, for example, the flow rate per unit area and unit time (the first flow rate) of the first cleaning liquid 11 ejected from the first ejector 21b can be set to 200 L / min / m 2 The above can also be set to 300 L / min / m 2 The above. The flow rate per unit area and unit time (the second flow rate) of the second cleaning liquid 12 dispersed by the cleaning liquid disperser 22b can be set to 50 L / min / m 2 ~150 L / min / m 2 ( Figure 2 The indicated normal flow rate range).

[0064] The second cleaning liquid 12 dispersed by the cleaning liquid disperser 22b flows down along the surface of the internal structure constituting the cleaning and recovery packing layer 22d while making gas-liquid contact with the carbon dioxide-removed combustion exhaust gas 3. Therefore, even if the flow rate per unit area and unit time of the second cleaning liquid 12 is made larger than 150 L / min / m 2, its contribution to improving the cleaning efficiency of the decarbonized combustion exhaust gas 3 is also limited. In addition, increasing the flow rate of the second cleaning liquid 12 beyond the necessary level will increase the capacity of the second circulation pump 55 and increase the operating cost, which is not preferable. However, in the first cleaning section 21, no components such as a packing layer are provided, and the first cleaning liquid 11 sprayed from the first injector 21b contacts the decarbonized combustion exhaust gas 3 in a mist state. Increasing the flow rate of the first cleaning liquid 11 per unit area and unit time can help increase the physical collision probability with the misty amine in the decarbonized combustion exhaust gas 3 and improve the cleaning efficiency of the decarbonized combustion exhaust gas 3. This is shown in Figure 2 In.

[0065] Figure 2 It is a graph showing the relationship between the flow rate of the first cleaning liquid 11 and the removal rate (recovery efficiency) of the misty amine. The data was obtained under the test conditions shown below.

[0066] · Inner diameter of the test device (equivalent to the inner diameter of the part of the absorption tower container 20c where the first cleaning section 21 is provided) 157 mm

[0067] · Flow rate of the treated gas (equivalent to the flow rate of the decarbonized combustion exhaust gas 3) 0.7 m / s

[0068] · Number concentration of misty amine (particle size 0.61 μm - 0.95 μm) approximately 10,000 particles / cc

[0069] · Center particle size of the cleaning liquid mist approximately 300 μm

[0070] · Pressure of the cleaning liquid 0.2 MPa

[0071] As Figure 2 shown in, within the normal flow rate range of the second cleaning liquid 12, the removal rate of the misty amine is low, but if it exceeds this range, the removal rate gradually increases. If the flow rate becomes 300 L / min / m 2 or more, it indicates a significant removal effect. If the flow rate becomes 300 L / min / m 2 or more, the removal effect can be improved. If the flow rate becomes 300 L / min / m 2 or more, the removal rate exceeds 70%, and the removal rate of the misty amine can be improved.

[0072] In addition, as Figure 1 shown in, the regeneration tower 30 has a regeneration cleaning section 37 that cleans the carbon dioxide-containing gas 8 discharged from the above-mentioned amine regeneration section 30a with condensed water 9 and recovers the amine accompanying the carbon dioxide-containing gas 8. The regeneration cleaning section 37 is provided above the amine regeneration section 30a.

[0073] The regeneration cleaning section 37 has a regeneration tower recovery section 37a and a liquid disperser 37b provided above the regeneration tower recovery section 37a.

[0074] The regeneration tower recovery section 37a is configured in the form of a countercurrent gas-liquid contact device. As an example, the regeneration tower recovery section 37a includes a regeneration tower recovery packing layer 37d. The regeneration tower recovery packing layer 37d is composed of internal structures such as packings and particles filled inside for increasing the gas-liquid contact area. The condensed water 9 flows down the surface of the internal structures while making gas-liquid contact with the carbon dioxide-containing gas 8, and amines are recovered (or removed) from the carbon dioxide-containing gas 8.

[0075] The liquid disperser 37b is configured to disperse and drop the condensed water 9 toward the regeneration tower recovery section 37a. The condensed water 9 is supplied to the surface of the internal structures of the regeneration tower recovery packing layer 37d. The pressure of the condensed water 9 supplied to the liquid disperser 37b is not so high relative to the pressure inside the regeneration tower 30, and the liquid disperser 37b is not substantially forced, and the condensed water 9 mainly drops onto the regeneration tower recovery packing layer 37d by the action of gravity.

[0076] Incidentally, above the amine regeneration section 30a of the regeneration tower 30, a first regeneration tower demister 86 is provided. The first regeneration tower demister 86 is provided between the amine regeneration section 30a and the regeneration cleaning section 37 (more specifically, between the liquid disperser 30b and the regeneration tower recovery section 37a). Thus, the carbon dioxide-containing gas 8 discharged from the amine regeneration section 30a rises through the first regeneration tower demister 86. The first regeneration tower demister 86 captures the mist accompanying the passed carbon dioxide-containing gas 8. The first regeneration tower demister 86 can effectively capture the misty amine. In addition, since the condensed water 9 falling from the liquid disperser 37b adheres to the first regeneration tower demister 86, the first regeneration tower demister 86 can also capture the gaseous amine.

[0077] Above the regeneration cleaning section 37, a second regeneration tower demister 87 is provided. The second regeneration tower demister 87 is provided above the liquid disperser 37b of the regeneration cleaning section 37 (more specifically, between the liquid disperser 37b and the top of the regeneration tower container 30c). Thus, the carbon dioxide-containing gas 8 discharged from the regeneration cleaning section 37 rises through the second regeneration tower demister 87. The second regeneration tower demister 87 can effectively capture the misty amine and the mist of the condensed water 9 accompanying the passed carbon dioxide-containing gas 8. In addition, since the condensed water 9 adheres to the second regeneration tower demister 87, the second regeneration tower demister 87 can also capture the gaseous amine.

[0078] Next, the operation of the present embodiment having such a configuration, that is, the operation method of the carbon dioxide recovery system, will be described.

[0079] In Figure 1 In the operation of the carbon dioxide recovery system shown, in the carbon dioxide recovery packing layer 20d of the carbon dioxide recovery section 20a of the absorption tower 20, the lean solution 5 supplied from the lean solution cooler 35 is sprayed as the first cleaning liquid 11 from the first ejector 21b and falls in the first cleaning and recovery space 21a. The first cleaning liquid 11 that has passed through the first cleaning and recovery space 21a reaches the carbon dioxide recovery section 20a. Moreover, the first cleaning liquid 11, as the lean solution 5, flows down along the surface of the internal structure in the carbon dioxide recovery packing layer 20d while making gas-liquid contact with the combustion exhaust gas 2. Carbon dioxide contained in the combustion exhaust gas 2 is absorbed into the lean solution 5. The combustion exhaust gas 2 is discharged from the carbon dioxide recovery section 20a as the de-carbonated combustion exhaust gas 3.

[0080] The de-carbonated combustion exhaust gas 3 that has passed through the carbon dioxide recovery section 20a reaches the first cleaning and recovery space 21a of the first cleaning section 21.

[0081] In the first cleaning and recovery space 21a, as described above, the first cleaning liquid 11 sprayed from the spray nozzle holes of the first ejector 21b falls and directly reaches the carbon dioxide recovery section 20a. During this period, the first cleaning liquid 11 falls in a mist state while physically colliding with the de-carbonated combustion exhaust gas 3, and the de-carbonated combustion exhaust gas 3 is cleaned by the first cleaning liquid 11. As a result, the mist-like amine accompanying the de-carbonated combustion exhaust gas 3 is effectively recovered into the first cleaning liquid 11.

[0082] As Figure 1 shown, the de-carbonated combustion exhaust gas 3 cleaned by the first cleaning liquid 11 is discharged from the first cleaning and recovery space 21a of the first cleaning section 21. Moreover, the de-carbonated combustion exhaust gas 3 further rises in the second cleaning section 22 and passes through the second cleaning section outlet demister 82. At this time, the mist-like amine accompanying the de-carbonated combustion exhaust gas 3 and the mist of the first cleaning liquid 11 are captured by the second cleaning section outlet demister 82.

[0083] The de-carbonated combustion exhaust gas 3 that has passed through the second cleaning section outlet demister 82 is discharged from the top of the absorption tower container 20c to the atmosphere.

[0084] Here, a general problem in cleaning the de-carbonated combustion exhaust gas 3 in the carbon dioxide recovery system 1 will be described.

[0085] Generally, in the carbon dioxide recovery system 1, in order to recover the amine accompanying the de-carbonated combustion exhaust gas 3, a packing layer or a tray on which the cleaning liquid flows down may be provided. In this case, the contact area between the de-carbonated combustion exhaust gas 3 and the cleaning liquid increases, and the amine can be effectively recovered.

[0086] The amines accompanying the carbon dioxide-removed combustion exhaust gas 3 are roughly classified into gaseous amines and mist-like amines. Among them, the gaseous amines are easily recovered by cleaning using a cleaning liquid, a packing layer, etc. On the other hand, the mist-like amines are difficult to recover by cleaning using a cleaning liquid, a packing layer, etc. The mist-like amines are easily captured by a demister, but if the particle size of the mist becomes 5 μm or less, even the demister has difficulty in capturing them. In order to improve the removal rate of the mist-like amines with a particle size of 5 μm or less, it is considered to use a high-density demister, but the high-density demister may increase the pressure loss caused by the flow of the carbon dioxide-removed combustion exhaust gas 3 passing through. In such a case, the power of the blower for supplying the combustion exhaust gas 2 to the absorption tower 20 increases, and the operating cost becomes high. In addition, when using a high-density demister, problems such as clogging of the demister are also considered.

[0087] Therefore, in the present embodiment, by atomizing the cleaning liquid, an improvement in the removal efficiency (recovery efficiency) of the mist-like amines is sought. That is, in the present embodiment, the pressure of the first cleaning liquid 11 supplied to the first ejector 21b of the first cleaning unit 21 is increased, and the first cleaning liquid 11 is ejected from the spray nozzle holes of the first ejector 21b at high speed (especially just after ejection). As a result, the mist of the first cleaning liquid 11 physically collides with the mist-like amines accompanying the carbon dioxide-removed combustion exhaust gas 3, and the mist-like amines are captured in the mist of the first cleaning liquid 11 and recovered. The first cleaning liquid 11 that has recovered the mist-like amines falls to the carbon dioxide recovery unit 20a. By operating in this way, the mist-like amines that are difficult to be captured by cleaning using a cleaning liquid, a packing layer, etc. are recovered in the first cleaning liquid 11, and the carbon dioxide-removed combustion exhaust gas 3 is effectively cleaned. Moreover, the problem of the pressure loss generated when using a high-density demister as described above can be avoided.

[0088] Here, for a general cleaning liquid, sometimes pure water is used instead of the absorption liquids 4 and 5. In this case, the amine concentration of the cleaning liquid is low, and even when the amine is captured, the amine concentration of the cleaning liquid is lower than that of the absorption liquids 4 and 5. Therefore, there is a problem that it is difficult to use such a cleaning liquid as an absorption liquid. In order to increase the amine concentration, it is considered to perform distillation treatment or membrane-based concentration treatment on the cleaning liquid, but in this case, there is a problem of increased energy consumption.

[0089] In contrast, in the present embodiment, the lean solution 5 is used as the first cleaning liquid 11, and the lean solution 5 is ejected from the first ejector 21b. The mist of the lean solution 5 ejected from the first ejector 21b physically collides with the mist-like amines accompanying the carbon dioxide-removed combustion exhaust gas 3. As a result, the mist-like amines can be effectively captured by the mist of the lean solution 5. The lean solution 5 that has captured the mist-like amines is supplied to the carbon dioxide recovery unit 20a and used as an absorption liquid.

[0090] In addition, in the present embodiment, the first cleaning liquid 11 with increased pressure is supplied to the ejector 21b of the first cleaning unit 21, and the first cleaning liquid 11 is ejected from the first ejector 21b. Thereby, the mist of the first cleaning liquid 11 can be formed, and the cleaning efficiency of the first cleaning unit 21 can be improved. For example, when the mist of the first cleaning liquid 11 is formed using ultrasonic vibration energy, the first cleaning liquid 11 forms a finely divided spray state, and it becomes difficult to make the mist of the first cleaning liquid 11 have a sufficient velocity component in the vertical direction. In addition, when using ultrasonic vibration energy, the pressure of the first cleaning liquid 11 is 0.1 MPa or less as described later. Therefore, in this regard, it also becomes difficult to make the mist of the first cleaning liquid 11 have a sufficient velocity component in the vertical direction. For this, in the present embodiment, as described later, the pressure of the first cleaning liquid 11 supplied to the first ejector 21b is increased to, for example, 0.1 MPa to 1.0 MPa. Therefore, the first cleaning liquid 11 can be ejected and atomized at high speed, and the cleaning efficiency of the first cleaning unit 21 can be improved.

[0091] In addition, as described above, the first cleaning liquid 11 ejected from the first ejector 21b freely falls without contacting the surface of the structure or the like in the first cleaning recovery space 21a where no filling layer or the like is provided. In this case, since the mist of the first cleaning liquid 11 does not collide with components such as the structure and directly reaches the carbon dioxide recovery unit 20a, the mist of the first cleaning liquid 11 can be prevented from being finely divided.

[0092] That is, in the case of having a recovery unit (the cleaning recovery unit 22a shown in Figure 3 described later) formed by a filling layer or the like, such as the first cleaning unit 21 or the second cleaning unit 22, the mist of the first cleaning liquid 11 ejected at high speed from the first ejector 21b collides with the filling layer or the like and is finely divided. In this case, the particle diameter of the mist of the first cleaning liquid 11 becomes smaller, and it becomes easier to flow backward along with the decarbonized combustion exhaust gas 3. Therefore, the first cleaning liquid 11 that has recovered the amine is released into the atmosphere along with the decarbonized combustion exhaust gas 3, and there is a problem that the amount of amine discharged into the atmosphere may increase.

[0093] However, in the present embodiment, a first cleaning and recovery space 21a is formed below the first ejector 21b, and no structures such as a packing layer and other components are provided. Therefore, atomization of the first cleaning liquid 11 can be suppressed, and a decrease in the cleaning efficiency of the first cleaning unit 21 can be suppressed. For example, by setting the distance from the first ejector 21b to the carbon dioxide recovery packing layer 20d to be at least 1 m or more, preferably 1.5 m or more, a sufficient first cleaning and recovery space 21a can be provided. In this case, when the mist of the first cleaning liquid 11 reaches the carbon dioxide recovery packing layer 20d, its speed can be reduced, and atomization due to collision with the carbon dioxide recovery packing layer 20d can be suppressed. In addition, in order to suppress the mist of the ejected first cleaning liquid 11 from being entrained in the carbon dioxide-removed combustion exhaust gas 3, the distance from the first ejector 21b to the carbon dioxide recovery packing layer 20d can be set to 5 m or less.

[0094] According to this embodiment, in this way, the carbon dioxide-removed combustion exhaust gas 3 discharged from the carbon dioxide recovery unit 20a is cleaned by the first cleaning liquid 11 ejected from the first ejector 21b of the first cleaning unit 21, and the amine entrained in the carbon dioxide-removed combustion exhaust gas 3 is recovered. As a result, the first cleaning liquid 11 can be atomized, and the mist of the first cleaning liquid 11 can physically collide with the mist-like amine entrained in the carbon dioxide-removed combustion exhaust gas 3 discharged from the carbon dioxide recovery unit 20a. Therefore, the mist-like amine can be effectively recovered into the first cleaning liquid 11, and the cleaning efficiency of the carbon dioxide-removed combustion exhaust gas 3 can be improved. As a result, the amount of amine discharged into the atmosphere can be reduced, and the amount of amine discharged from the carbon dioxide recovery system 1 to the outside can be reduced.

[0095] In addition, according to this embodiment, the lean solution pipeline 16 can supply the lean solution 5 discharged from the amine regeneration unit 30a of the regeneration tower 30 to the first ejector 21b as the first cleaning liquid 11. As a result, the first cleaning liquid 11 using the lean solution 5 can be ejected from the first ejector 21b, and the mist of the first cleaning liquid 11 can physically collide with the mist-like amine entrained in the carbon dioxide-removed combustion exhaust gas 3. Therefore, even without using a liquid different from the lean solution 5 such as cleaning water, the mist-like amine can be captured by the lean solution 5. The captured amine is contained in the lean solution 5 and can be used as an absorption liquid. As a result, the amine recovered from the carbon dioxide-removed combustion exhaust gas 3 can be easily utilized.

[0096] In addition, according to this embodiment, the first cleaning unit 21 has a first cleaning and recovery space 21a in which the mist of the first cleaning liquid 11 ejected from the first ejector 21b freely falls while contacting the carbon dioxide-removed combustion exhaust gas 3. As a result, collision of the mist of the first cleaning liquid 11 ejected from the first ejector 21b with structures and other components can be suppressed. Therefore, atomization of the mist of the first cleaning liquid 11 and its entrainment in the carbon dioxide-removed combustion exhaust gas 3 can be suppressed.

[0097] In addition, according to the present embodiment, the first ejector 21b faces the carbon dioxide recovery unit 20a. Thus, the mist of the first cleaning liquid 11 ejected from the first ejector 21b can reach the carbon dioxide recovery unit 20a through the first cleaning and recovery space 21a. Moreover, the first cleaning liquid 11 can be supplied to the carbon dioxide recovery unit 20a as the lean solution 5. Therefore, even without using a liquid different from the lean solution 5 such as cleaning water, the decarbonized combustion exhaust gas 3 discharged from the carbon dioxide recovery unit 20a can be cleaned with the lean solution 5. In this case, the first circulation pipeline 50 and the like shown in etc. can be dispensed with. As a result, the structure extending from the carbon dioxide recovery unit 20a across the first cleaning unit 21 can be simplified. Figure 3 and the like.

[0098] In addition, in the above-described present embodiment, an example in which the carbon dioxide recovery unit 20a includes a carbon dioxide recovery packing layer 20d has been described. However, the present invention is not limited thereto, and the carbon dioxide recovery unit 20a may be composed of a tray (not shown). The same applies to the cleaning and recovery unit 22a, the amine regeneration unit 30a, and the regeneration tower recovery unit 37a.

[0099] (Second Embodiment)

[0100] Next, Figure 3 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the second embodiment of the present invention.

[0101] In Figure 3 The second embodiment shown in is mainly different in that the absorption liquid pipeline is connected to the first circulation pipeline that supplies the first cleaning liquid in the first receiving portion to the first ejector, and other configurations are substantially the same as those in the first embodiment shown in and. It should be noted that in, the same parts as those in the first embodiment shown in and are denoted by the same reference numerals and detailed descriptions thereof are omitted. Figure 1 and Figure 2 In this embodiment, as Figure 3 in Figure 1 and Figure 2 in the first embodiment shown in are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0102] In this embodiment, as Figure 3As shown, the first cleaning unit 21 further includes a first receiving unit 21c provided below the first cleaning and recovery space 21a. The first cleaning and recovery space 21a is formed across the carbon dioxide recovery unit 20a from the first ejector 21b. The mist of the first cleaning liquid 11 ejected from the first ejector 21b falls in the first cleaning and recovery space 21a and directly reaches the first receiving unit 21c. That is, the first cleaning liquid 11 that has passed through the first cleaning and recovery space 21a is directly received by the first receiving unit 21c. The first receiving unit 21c is composed of a receiving unit main body that receives and stores the first cleaning liquid 11, an opening through which the decarbonized combustion exhaust gas 3 passes provided between the receiving unit main bodies, and a cover that covers the opening from above and is used to inhibit the first cleaning liquid 11 from passing through the opening.

[0103] Connected to the first cleaning unit 21 is a first circulation pipeline 50 for circulating the first cleaning liquid 11. That is, a first circulation pump 51 is provided on the first circulation pipeline 50. A part of the first cleaning liquid 11 stored in the first receiving unit 21c is pumped out from the first receiving unit 21c by the first circulation pump 51 and supplied to the first ejector 21b through the first circulation pipeline 50. Thus, the first cleaning liquid 11 circulates. The pressure of the first cleaning liquid 11 supplied to the first ejector 21b is increased by the first circulation pump 51.

[0104] The first cleaning and recovery space 21a according to the present embodiment can be delimited by the distance from the first ejector 21b to the first receiving unit 21c. In this case, by setting the distance from the first ejector 21b to the first receiving unit 21c to at least 1 m or more, preferably 1.5 m or more, a sufficient first cleaning and recovery space 21a can be provided. In addition, the distance from the first ejector 21b to the first receiving unit 21c can be set to 5 m or less.

[0105] The lean solution pipeline 16 according to the present embodiment is connected to the first circulation pipeline 50. The lean solution pipeline 16 can also be connected to a position on the first circulation pipeline 50 that is more upstream than the first circulation pump 51. More specifically, the downstream end of the lean solution pipeline 16 can be connected to a position on the first circulation pipeline 50 that is more upstream than the first circulation pump 51. The lean solution 5 supplied from the lean solution pipeline 16 is mixed into the first cleaning liquid 11 flowing through the first circulation pipeline 50. The first cleaning liquid 11 mixed with the lean solution 5 is supplied to the first ejector 21b by the first circulation pump 51.

[0106] In addition, in the present embodiment, a liquid disperser 20b is provided above the carbon dioxide recovery unit 20a. The liquid disperser 20b is configured to disperse and drop the first cleaning liquid 11 supplied from a bypass line 60 (to be described later) as the lean solution 5 toward the carbon dioxide recovery unit 20a. The lean solution 5 is supplied from the liquid disperser 20b to the surface of the internal structure of the carbon dioxide recovery packing layer 20d. The pressure of the lean solution 5 supplied to the liquid disperser 20b is not so high relative to the pressure inside the absorption tower 20, and the liquid disperser 20b is not substantially forced, and the lean solution 5 mainly drops by the action of gravity onto the carbon dioxide recovery packing layer 20d.

[0107] The first receiving unit 21c and the liquid disperser 20b are connected by a bypass line 60. The bypass line 60 supplies a part of the first cleaning liquid 11 in the first receiving unit 21c to the liquid disperser 20b. A pump (not shown) may be provided on the bypass line 60, or may not be provided. Even in the latter case, due to the action of gravity, the first cleaning liquid 11 stored in the first receiving unit 21c can be supplied to the liquid disperser 20b.

[0108] Thus, according to the present embodiment, the lean solution line 16 is connected to the first circulation line 50 that supplies the first cleaning liquid 11 in the first receiving unit 21c to the first ejector 21b. Thereby, the lean solution 5 can be mixed into the first cleaning liquid 11 and supplied to the first ejector 21b. Therefore, the misty amine accompanying the decarbonized combustion exhaust gas 3 can be captured by the mist of the first cleaning liquid 11 ejected from the first ejector 21b.

[0109] In addition, according to the present embodiment, the mist of the first cleaning liquid 11 ejected from the first ejector 21b is received by the first receiving unit 21c. Thereby, the lean solution that has captured the misty amine can be stored in the first receiving unit 21c. When a flow rate adjustment pump (not shown) is provided on at least one of the first circulation line 50 and the bypass line 60, the supply amount of the first cleaning liquid 11 supplied to the first ejector 21b and the supply amount of the lean solution 5 supplied from the liquid disperser 20b can be adjusted. Therefore, appropriate operation according to the situation can be performed. For example, the ejection amount of the first cleaning liquid 11 ejected from the first ejector 21b can be made larger than the supply amount of the lean solution 5 supplied from the liquid disperser 20b. In this case, the ejection amount of the first cleaning liquid 11 ejected from the first ejector 21b can be increased, and the capturing ability of the misty amine can be improved.

[0110] In addition, according to the present embodiment, the lean solution pipeline 16 is connected to a position upstream of the first circulation pump 51 in the first circulation pipeline 50. This can prevent the lean solution 5 from flowing back in the lean solution pipeline 16. That is, when the injection amount of the first cleaning liquid 11 injected from the first ejector 21b is increased, the ejection amount of the first circulation pump 51 increases. When the lean solution pipeline 16 is connected to a position downstream of the first circulation pump 51 in the first circulation pipeline 50, the possibility of the lean solution 5 flowing back in the lean solution pipeline 16 is considered along with the ejection amount of the first circulation pump 51. However, according to the present embodiment, the lean solution pipeline 16 is connected to a position upstream of the first circulation pump 51. Thus, the backflow of the lean solution 5 in the lean solution pipeline 16 can be suppressed.

[0111] In addition, according to the present embodiment, the bypass pipeline 60 supplies the first cleaning liquid 11 in the first receiving portion 21c to the carbon dioxide recovery portion 20a. Thus, the first cleaning liquid 11 that has captured the mist-like amine can be supplied to the liquid disperser 20b through the bypass pipeline 60 and can be used as an absorption liquid. Therefore, the amine recovered from the carbon dioxide-removed combustion exhaust gas 3 can be easily utilized.

[0112] (Third Embodiment)

[0113] Next, Figure 4 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the third embodiment of the present invention.

[0114] In Figure 4 shown in the third embodiment, the main difference is that a cleaning liquid distributor capable of adjusting the supply amount of the first cleaning liquid to the first ejector and the supply amount of the first cleaning liquid to the carbon dioxide recovery portion is provided on the first circulation pipeline. Other configurations are substantially the same as those in Figure 3 shown in the second embodiment. It should be noted that Figure 4 identical parts to those in Figure 3 shown in the second embodiment are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0115] In the present embodiment, as Figure 4 shown, a cleaning liquid distributor 61 is provided on the first circulation pipeline 50. The cleaning liquid distributor 61 is arranged on the downstream side of the connection position between the first circulation pipeline 50 and the lean solution pipeline 16. A cleaning liquid distribution pipeline 62 for supplying the first cleaning liquid 11 to the carbon dioxide recovery portion 20a is connected to the cleaning liquid distributor 61. The upstream end of the cleaning liquid distribution pipeline 62 is connected to the cleaning liquid distributor 61, and the downstream end of the cleaning liquid distribution pipeline 62 is connected to the liquid disperser 20b. In the present embodiment, the Figure 3 shown bypass pipeline 60 is not provided.

[0116] The cleaning liquid dispenser 61 can distribute the first cleaning liquid 11 between the first ejector 21b and the carbon dioxide recovery section 20a. More specifically, the cleaning liquid dispenser 61 can adjust the supply amount of the first cleaning liquid 11 to the first ejector 21b and the supply amount of the first cleaning liquid 11 to the carbon dioxide recovery section 20a. That is, the cleaning liquid dispenser 61 can adjust the supply amount of the first cleaning liquid 11 supplied to the first ejector 21b and the supply amount of the first cleaning liquid 11 supplied to the liquid disperser 20b. For example, the supply amount of the first cleaning liquid 11 to the first ejector 21b can be made larger than the supply amount of the first cleaning liquid 11 supplied to the liquid disperser 20b.

[0117] In addition, for example, based on the water content (more specifically, the water content rate) of the absorption liquids 4 and 5, the amount of the first cleaning liquid 11 distributed can be adjusted. Examples of the water that flows into the absorption liquids 4 and 5 include the water contained in the combustion exhaust gas 2. On the other hand, examples of the water that flows out of the absorption liquids 4 and 5 include the water contained in the carbon dioxide-removed combustion exhaust gas 3 or amines, etc. In addition, in order to adjust the water content of the absorption liquids 4 and 5, the water discharged from the absorption liquids 4 and 5 to the outside of the carbon dioxide recovery system 1 can also be cited. Therefore, the flow rate of the lean solution 5 supplied to the carbon dioxide recovery section 20a and the flow rate of the lean solution 5 discharged from the regeneration tower 30 can also be made inconsistent. The cleaning liquid dispenser 61 can adjust the flow rate of the first cleaning liquid 11 distributed through the cleaning liquid dispenser 61 for the purpose of keeping the water content of the absorption liquids 4 and 5 constant. In this case, the storage amount of the lean solution 5 stored in a buffer tank (not shown) can be measured, and the amount distributed by the cleaning liquid dispenser 61 can be adjusted based on this storage amount. For example, when the storage amount is large, the supply amount of the first cleaning liquid 11 to the first ejector 21b is increased, and when the storage amount is small, the supply amount of the first cleaning liquid 11 to the carbon dioxide recovery section 20a is increased. Instead of the storage amount of the lean solution 5, the water content contained in the lean solution 5 can also be measured, and the amount distributed by the cleaning liquid dispenser 61 can be adjusted. For example, in the measurement of the water content, a measuring device using the principle of the Karl Fischer titration method or gas chromatography can be used. In this case, the measured value can suppress the decrease in the carbon dioxide recovery ability and suppress the increase in the viscosity of the absorption liquids 4 and 5 by adjusting the water content of the absorption liquids 4 and 5. The buffer tank can be arranged, for example, between the heat exchanger 31 and the lean solution cooler 35 in the lean solution pipeline 16.

[0118] Thus, according to this embodiment, a cleaning liquid distributor 61 capable of adjusting the supply amount of the first cleaning liquid 11 to the first ejector 21b and the supply amount of the first cleaning liquid 11 to the carbon dioxide recovery unit 20a is provided on the first circulation pipeline 50. Thereby, the supply amount of the first cleaning liquid 11 to the first ejector 21b and the supply amount of the first cleaning liquid 11 to the carbon dioxide recovery unit 20a can be adjusted. Therefore, the moisture content of the absorbent liquids 4 and 5 can be adjusted, and the operation of the carbon dioxide recovery system 1 can be stabilized.

[0119] (Fourth Embodiment)

[0120] Next, Figure 5 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the fourth embodiment of the present invention.

[0121] In Figure 5 shown in the fourth embodiment, the main difference is that an absorbent liquid distributor capable of adjusting the supply amount of the absorbent liquid to the first circulation pipeline and the supply amount of the absorbent liquid to the carbon dioxide recovery unit is provided on the absorbent liquid pipeline. The other configurations are substantially the same as those in Figure 3 shown in the second embodiment. It should be noted that Figure 5 in, the same parts as those in Figure 3 shown in the second embodiment are marked with the same reference numerals and detailed descriptions are omitted.

[0122] In this embodiment, as Figure 5 shown, an absorbent liquid distributor 63 is provided on the lean solution pipeline 16. The absorbent liquid distributor 63 is arranged on the downstream side of the lean solution cooler 35 in the lean solution pipeline 16. An absorbent liquid distribution pipeline 64 for supplying the lean solution 5 to the carbon dioxide recovery unit 20a is connected to the absorbent liquid distributor 63. The upstream end of the absorbent liquid distribution pipeline 64 is connected to the absorbent liquid distributor 63, and the downstream end of the absorbent liquid distribution pipeline 64 is connected to the liquid disperser 20b.

[0123] The lean solution distributor 63 can distribute the lean solution 5 in the first circulation pipeline 50 and the carbon dioxide recovery unit 20a. More specifically, the lean solution distributor 63 can adjust the supply amount of the lean solution 5 to the first circulation pipeline 50 and the supply amount of the lean solution 5 to the carbon dioxide recovery unit 20a. That is, the lean solution distributor 63 can adjust the supply amount of the lean solution 5 supplied to the first circulation pipeline 50 and the supply amount of the lean solution 5 supplied to the liquid disperser 20b. For example, the amount of the distributed lean solution 5 can be adjusted in such a way that the storage amount of the first cleaning liquid 11 stored in the first receiving portion 21c becomes constant. In this case, the liquid level of the first cleaning liquid 11 stored in the first receiving portion 21c can be measured, and the amount of the distributed lean solution 5 can be adjusted in such a way that the liquid level becomes constant. For example, when the storage amount is large, the supply amount of the lean solution 5 to the carbon dioxide recovery unit 20a is increased, and when the storage amount is small, the supply amount of the lean solution 5 to the first circulation pipeline 50 is increased. In this way, the injection amount of the first cleaning liquid 11 injected from the first ejector 21b can be ensured, and the capturing ability of the atomized amine can be ensured.

[0124] Thus, according to this embodiment, a lean solution distributor 63 capable of adjusting the supply amount of the lean solution 5 to the first circulation pipeline 50 and the supply amount of the lean solution 5 to the carbon dioxide recovery unit 20a is provided on the lean solution pipeline 16. Thereby, the supply amount of the lean solution 5 to the first circulation pipeline 50 and the supply amount of the lean solution 5 to the carbon dioxide recovery unit 20a can be adjusted. Therefore, for example, the storage amount of the first cleaning liquid 11 stored in the first receiving portion 21c can be made constant, the injection amount of the first cleaning liquid 11 injected from the first ejector 21b can be ensured, and the capturing ability of the atomized amine can be ensured.

[0125] In addition, according to this embodiment, the lean solution distributor 63 is arranged on the downstream side of the lean solution cooler 35. Thereby, even when the temperature of the lean solution 5 discharged from the heat exchanger 31 is high, the temperature of the lean solution 5 supplied to the carbon dioxide recovery unit 20a can be reduced to a temperature at which the carbon dioxide recovery efficiency is good. Therefore, in the carbon dioxide recovery unit 20a, the recovery efficiency of recovering carbon dioxide from the combustion exhaust gas 2 can be improved.

[0126] (The fifth embodiment)

[0127] Next, Figure 6 , the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the fifth embodiment of the present invention will be described.

[0128] In Figure 6 the main difference in the fifth embodiment shown is that the lean solution cooler is arranged on the lean solution distribution pipeline, and the other configurations are substantially the same as those in Figure 5 the fourth embodiment shown. It should be noted thatFigure 6 In Figure 5 the same parts as those in the fourth embodiment shown in

[0129] are denoted by the same reference numerals and detailed descriptions thereof are omitted. Figure 6 In the present embodiment, as

[0130] shown in

[0131] an absorber liquid distributor 65 is provided on the lean solution pipeline 16. An absorber liquid distribution pipeline 66 for supplying the lean solution 5 to the carbon dioxide recovery section 20a is connected to the absorber liquid distributor 65. The upstream end of the absorber liquid distribution pipeline 66 is connected to the absorber liquid distributor 65, and the downstream end of the absorber liquid distribution pipeline 66 is connected to the liquid disperser 20b.

[0132] Here, the misty amine accompanying the carbon dioxide-removed combustion exhaust gas 3 is difficult to recover by cleaning using a cleaning liquid, a packing layer, etc. Therefore, in the present embodiment, the mist of the first cleaning liquid 11 ejected from the first ejector 21b of the first cleaning section 21 is made to collide with the misty amine, and the misty amine is recovered into the mist of the first cleaning liquid 11. However, if the particle size of the misty amine becomes smaller (for example, if it becomes 0.5 μm or less), the recovery efficiency of the misty amine decreases. Therefore, in order to improve the recovery efficiency of the misty amine, it is effective to increase the particle size of the misty amine.

[0133] As a method of increasing the particle size of the misty amine, it is considered to make the temperature of the second cleaning section 22 lower than the temperature of the first cleaning section 21 and to widen the temperature difference between the two. In this case, when the carbon dioxide-removed combustion exhaust gas 3 passes through the second cleaning section 22, it is cooled, the water vapor contained in the carbon dioxide-removed combustion exhaust gas 3 condenses, and the condensed moisture can be captured by the misty amine to increase the particle size of the misty amine.

[0134] As methods of making the temperature of the second cleaning section 22 lower than the temperature of the first cleaning section 21, two are considered. The first is a method of heating the first cleaning section 21, and the second is a method of cooling the second cleaning section 22.

[0135] For the purpose of reducing the amine vapor pressure in the cleaning liquid, the cleaning liquid is sometimes cooled. However, the operating temperature of a general cleaning liquid is around 30°C to 40°C. In contrast, the temperature of the cooled cleaning liquid stays around 20°C to 30°C, and the temperature difference obtained by cooling becomes smaller. Thus, it becomes difficult to enlarge the temperature difference between the first cleaning section 21 and the second cleaning section 22 by cooling the second cleaning liquid 12. In addition, when the second cleaning liquid 12 is cooled using a chiller or the like with high cooling capacity in order to enlarge the temperature difference, although the temperature of the cleaning liquid can be further reduced, the energy required for cooling increases sharply. One of the major problems of the carbon dioxide recovery system 1 is how to reduce the energy required for recovering carbon dioxide. Therefore, it is not preferable to increase the energy for cooling the decarbonated combustion exhaust gas 3.

[0136] Then, in the present embodiment, attention is paid to cooling the lean solution 5 discharged from the heat exchanger 31 using the lean solution cooler 35. That is, during operation, the temperature of the first cleaning section 21 is around 30°C to 40°C, but the temperature of the lean solution 5 discharged from the heat exchanger 31 is around 50°C to 60°C. The lean solution 5 before being cooled by the lean solution cooler 35 is supplied to the first cleaning section 21. Thereby, the temperature of the first cleaning liquid 11 can be increased, and the temperature difference between the first cleaning section 21 and the second cleaning section 22 can be enlarged. Therefore, the amount of condensed water in the second cleaning section 22 can be increased. The temperature of the first cleaning section 21 is preferably 5°C to 50°C higher than the temperature of the upper end portion of the carbon dioxide recovery section 20a, and more preferably 10°C to 30°C higher.

[0137] In addition, as Figure 6 shown, a bypass cooler 67 for cooling the first cleaning liquid 11 is provided on the bypass pipeline 60. As described above, the temperature of the first cleaning liquid 11 can be increased, so it is preferable to cool the first cleaning liquid 11 supplied from the first receiving section 21c to the liquid distributor 20b. Therefore, the bypass cooler 67 is provided on the bypass pipeline 60. The first cleaning liquid 11 stored in the first receiving section 21c is cooled by the bypass cooler 67 and then supplied to the liquid distributor 20b. The bypass cooler 67 can cool the first cleaning liquid 11 to the same degree as the temperature of the lean solution 5 cooled in the lean solution cooler 35 as shown in Figure 1 etc.

[0138] Thus, according to the present embodiment, an absorbent distributor 65 capable of adjusting the supply amount of the lean solution 5 to the first circulation line 50 and the supply amount of the lean solution 5 to the carbon dioxide recovery unit 20a is provided on the lean solution line 16. Thereby, the temperature of the lean solution 5 supplied to the first circulation line 50 can be increased, and the temperature of the first cleaning liquid 11 can be made higher than the temperature of the second cleaning liquid 12. Therefore, the temperature difference between the first cleaning liquid 11 and the second cleaning liquid 12 can be increased, and the particle size of the atomized amine can be increased. As a result, the recovery efficiency of the atomized amine can be improved. The discharge amount of amine into the atmosphere can be further reduced.

[0139] In addition, according to the present embodiment, a bypass cooler 67 for cooling the first cleaning liquid 11 is provided on the bypass line 60. Thereby, the first cleaning liquid 11 supplied to the liquid disperser 20b can be cooled, and the temperature of the first cleaning liquid 11 can be reduced. Therefore, the recovery efficiency of recovering carbon dioxide from the combustion exhaust gas 2 in the carbon dioxide recovery unit 20a can be improved.

[0140] (Sixth Embodiment)

[0141] Next, Figure 7 , the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the sixth embodiment of the present invention will be described.

[0142] In Figure 7 the sixth embodiment shown, the main difference is that the demister at the outlet of the first cleaning section is formed sparser than the demister at the outlet of the second cleaning section. Other configurations are substantially the same as those in Figure 6 the fifth embodiment shown. It should be noted that Figure 7 in Figure 6 the same parts as those in the fifth embodiment shown are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0143] In the present embodiment, as Figure 7 shown, the demister 81 at the outlet of the first cleaning section is formed sparser than the demister at the outlet of the second cleaning section.

[0144] Regarding whether the demister is formed sparsely or densely, it can be described, for example, by the space ratio of the demister. More specifically, the size of the space ratio of the demister can correspond to the sparseness or denseness of the demister. In this case, the demister 81 at the outlet of the first cleaning section is formed more sparsely than the demister 82 at the outlet of the second cleaning section, which means the same as the space ratio of the demister 81 at the outlet of the first cleaning section being larger than the space ratio of the demister 82 at the outlet of the second cleaning section. As a result, the space through which the carbon dioxide-removed combustion exhaust gas 3 passes in the demister 81 at the outlet of the first cleaning section increases, and the carbon dioxide-removed combustion exhaust gas 3 becomes easier to pass through. Therefore, the pressure loss generated by the flow of the carbon dioxide-removed combustion exhaust gas 3 can be reduced. For example, when the demister 81 at the outlet of the first cleaning section and the demister 82 at the outlet of the second cleaning section are mesh-shaped demisters, the mesh of the demister 81 at the outlet of the first cleaning section can be made coarser than the mesh of the demister 82 at the outlet of the second cleaning section.

[0145] In addition, regarding whether the demister is formed sparsely or densely, it can also be described, for example, by using the fog removal (or recovery) rate characteristics of the demister. More specifically, when the characteristics of the demister are represented by the fog removal rate in a specified particle size range (for example, 0.1 μm to 10 μm), the size of the removal rate can correspond to the sparseness or denseness of the demister. In this case, the demister 81 at the outlet of the first cleaning section is formed more sparsely than the demister 82 at the outlet of the second cleaning section, which means the same as the fog removal rate of the demister 81 at the outlet of the first cleaning section in the specified particle size range being smaller than the removal rate of the demister 82 at the outlet of the second cleaning section.

[0146] The fog of the first cleaning liquid 11 ejected from the first ejector 21b is larger in particle size than the fog-like amine accompanying the carbon dioxide-removed combustion exhaust gas 3, for example, with a diameter of 100 μm or more. The demister 81 at the outlet of the first cleaning section according to this embodiment is formed more sparsely than the demister 82 at the outlet of the second cleaning section. As a result, the demister 81 at the outlet of the first cleaning section can be constituted by a coarser demister than the demister 82 at the outlet of the second cleaning section. Therefore, an increase in pressure loss can be suppressed, and an increase in the power of the blower for supplying the combustion exhaust gas 2 to the absorption tower 20 can be suppressed. In addition, when the fog of the first cleaning liquid 11 with a large particle size is accompanied in the carbon dioxide-removed combustion exhaust gas 3, clogging in the demister 81 at the outlet of the first cleaning section can also be suppressed. In addition, when a large amount of the fog of the first cleaning liquid 11 is accompanied in the carbon dioxide-removed combustion exhaust gas 3, clogging in the demister 81 at the outlet of the first cleaning section can also be suppressed.

[0147] On the other hand, the demister 82 at the outlet of the second cleaning section can be constituted by a demister with a fine mesh, and can effectively capture the mist-like amine that cannot be captured by the demister 81 at the outlet of the first cleaning section. That is, the demister 82 at the outlet of the second cleaning section can not only remove the mist of the second cleaning liquid 12, but also remove the mist of the first cleaning liquid 11 with a relatively small particle size. In addition, the demister 82 at the outlet of the second cleaning section can capture the mist-like amine with a relatively small particle size that has passed through the demister 81 at the outlet of the first cleaning section. When passing through the second cleaning section 22, due to the condensation of moisture, the particle size expands, and the mist-like amine is also captured by the demister 82 at the outlet of the second cleaning section.

[0148] Thus, according to this embodiment, the demister 81 at the outlet of the first cleaning section is formed more sparsely than the demister 82 at the outlet of the second cleaning section. Thereby, it is possible to effectively capture the mist-like amine and the mist of the first cleaning liquid 11 accompanying the carbon dioxide-removed combustion exhaust gas 3, and to suppress an increase in the pressure loss in the demister 81 at the outlet of the first cleaning section, while suppressing the occurrence of blockage. In this case, it is possible to reduce the power of the blower for supplying the combustion exhaust gas 2 to the absorption tower 20, and to reduce the operating cost.

[0149] (Seventh Embodiment)

[0150] Next, Figure 8 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the seventh embodiment of the present invention.

[0151] In Figure 8 the seventh embodiment shown, the main difference is that the cleaning liquid mist recovery section provided between the first cleaning section and the second cleaning section has a mist recovery packing layer for recovering the mist of the first cleaning liquid. Other configurations are substantially the same as those of the fifth embodiment shown in Figure 6 . It should be noted that, Figure 8 for the parts that are the same as those of the fifth embodiment shown in Figure 6 , the same reference numerals are marked and the detailed description is omitted.

[0152] In the present embodiment, as shown in Figure 8 , a cleaning liquid mist recovery section 83 is provided between the first cleaning section 21 and the second cleaning section 22. The cleaning liquid mist recovery section 83 is provided above the first ejector 21b and below the second receiving section 22c. The cleaning liquid mist recovery section 83 is configured to recover the mist of the first cleaning liquid 11 accompanying the carbon dioxide-removed combustion exhaust gas 3 discharged from the first cleaning section 21.

[0153] The cleaning liquid mist recovery unit 83 can be configured in the form of a countercurrent gas-liquid contact device. As an example, the cleaning liquid mist recovery unit 83 includes a mist recovery packing layer 83a. The mist recovery packing layer 83a is composed of internal structures such as fillers and particles filled inside for increasing the gas-liquid contact area. The mist of the first cleaning liquid 11 accompanying the carbon dioxide-removed combustion exhaust gas 3 discharged from the first cleaning unit 21 is brought into contact with and adhered to the surface of the internal structure. Thereby, the mist of the first cleaning liquid 11 is recovered (or removed) from the carbon dioxide-removed combustion exhaust gas 3.

[0154] In the present embodiment, the mist recovery packing layer 83a of the cleaning liquid mist recovery unit 83 can be configured in such a manner that the pressure loss generated by the flow of the carbon dioxide-removed combustion exhaust gas 3 passing through is reduced more than that of the demister 82 at the outlet of the second cleaning unit. For example, the porosity of the mist recovery packing layer 83a can be larger than the porosity of the demister 82 at the outlet of the second cleaning unit. In other words, the specific surface area of the mist recovery packing layer 83a can be smaller than the specific surface area of the demister 82 at the outlet of the second cleaning unit. That is, the mist recovery packing layer 83a is intended to capture the mist of the first cleaning liquid 11 having a relatively large particle size. On the other hand, the demister 82 at the outlet of the second cleaning unit is intended to capture the misty amine accompanying the carbon dioxide-removed combustion exhaust gas 3, but the particle size of the misty amine is relatively small. Therefore, in order to reduce the pressure loss, the porosity of the mist recovery packing layer 83a can be larger than the porosity of the demister 82 at the outlet of the second cleaning unit, and the mist of the first cleaning liquid 11 can be effectively captured.

[0155] Thus, according to the present embodiment, the cleaning liquid mist recovery unit 83 provided between the first cleaning unit 21 and the second cleaning unit 22 has the mist recovery packing layer 83a for recovering the mist of the first cleaning liquid 11. Thereby, the misty amine and the mist of the first cleaning liquid 11 accompanying the carbon dioxide-removed combustion exhaust gas 3 can be effectively captured, the increase in the pressure loss in the cleaning liquid mist recovery unit 83 can be suppressed, and the occurrence of clogging can be suppressed. In this case, the power of the blower for supplying the combustion exhaust gas 2 to the absorption tower 20 can be reduced, and the operation cost can be reduced.

[0156] (Eighth Embodiment)

[0157] Next, Figure 9 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the eighth embodiment of the present invention.

[0158] In Figure 9 the eighth embodiment shown, the main difference is that the second cleaning unit uses the second ejector to inject the second cleaning liquid and recovers the amine accompanying the combustion exhaust gas with the mist of the second cleaning liquid. Other configurations are substantially the same as those of Figure 6 the fifth embodiment shown. It should be noted that Figure 9 in, forFigure 6 Parts identical to those of the fifth embodiment shown are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0159] In the present embodiment, as Figure 9 shown, the second cleaning unit 22 sprays the second cleaning liquid 12 with the second injector 22f, and recovers the amine accompanying the carbon dioxide-removed combustion exhaust gas 3 with the mist of the second cleaning liquid 12. More specifically, the second cleaning unit 22 includes a second cleaning and recovery space 22e, a second injector 22f provided above the second cleaning and recovery space 22e, and a second receiving unit 22c provided below the second cleaning and recovery space 22e.

[0160] The second cleaning and recovery space 22e is a space provided below the second injector 22f. In the present embodiment, the second cleaning and recovery space 22e is a space provided across the second receiving unit 22c from the second injector 22f. The second cleaning liquid 12 is sprayed from the second injector 22f into the second cleaning and recovery space 22e. The sprayed second cleaning liquid 12 falls freely in the form of a mist in the second cleaning and recovery space 22e (that is, falls in a state of not contacting the surfaces of structures in the space) while contacting the rising carbon dioxide-removed combustion exhaust gas 3. Thereby, the amine accompanying the carbon dioxide-removed combustion exhaust gas 3 is recovered. In the second cleaning unit 22, fog-like amine can be effectively recovered, but gaseous amine can also be effectively recovered.

[0161] In the present embodiment, as described above, a second cleaning and recovery space 22e is formed between the second injector 22f and the second receiving unit 22c. In the second cleaning and recovery space 22e, no structures such as a packing layer or a tray for allowing the second cleaning liquid 12 to flow on the surface while contacting the carbon dioxide-removed combustion exhaust gas 3 are provided. That is, between the second injector 22f and the second receiving unit 22c, no structures such as those for allowing the second cleaning liquid 12 to flow on the surface are provided, and the second cleaning and recovery space 22e is formed across the second receiving unit 22c from the second injector 22f. Thus, the second cleaning and recovery space 22e is configured such that the second cleaning liquid 12 contacts the carbon dioxide-removed combustion exhaust gas 3 while falling freely. The mist of the second cleaning liquid 12 sprayed from the second injector 22f falls in the second cleaning and recovery space 22e where the carbon dioxide-removed combustion exhaust gas 3 rises and directly reaches the second receiving unit 22c. That is, the second cleaning liquid 12 after passing through the second cleaning and recovery space 22e is directly received by the second receiving unit 22c. During the falling, the second cleaning liquid 12 contacts the carbon dioxide-removed combustion exhaust gas 3, and the fog-like amine accompanying the carbon dioxide-removed combustion exhaust gas 3 collides physically with the mist of the second cleaning liquid 12 and is recovered.

[0162] The second injector 22f injects the second cleaning liquid 12 toward the second cleaning and recovery space 22e to make it fall. The second injector 22f can be configured in the same manner as the first injector 21b. The second receiving portion 22c receives and stores the second cleaning liquid 12 that has fallen in the second cleaning and recovery space 22e. A second circulation pipeline 54 for circulating the second cleaning liquid 12 is connected to the second receiving portion 22c. The second cleaning liquid 12 stored in the second receiving portion 22c is pumped out and supplied to the second injector 22f. Thus, the second cleaning liquid 12 becomes circulated.

[0163] Thus, according to this embodiment, the second cleaning liquid 12 is injected by the second injector 22f, and the amine accompanying the decarbonized combustion exhaust gas 3 is recovered by the mist of the second cleaning liquid 12. As a result, the mist of the second cleaning liquid 12 can physically collide with the mist-like amine accompanying the decarbonized combustion exhaust gas 3 discharged from the first cleaning unit 21. Therefore, the mist-like amine can be effectively recovered into the second cleaning liquid 12. In addition, since the amine concentration of the second cleaning liquid 12 is lower than that of the first cleaning liquid 11, the gaseous amine accompanying the decarbonized combustion exhaust gas 3 can also be recovered. Therefore, the cleaning efficiency of the decarbonized combustion exhaust gas 3 can be further improved, and the emission amount of amine into the atmosphere can be further reduced.

[0164] (The ninth embodiment)

[0165] Next, Figure 10 will be used to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the ninth embodiment of the present invention.

[0166] In Figure 10 In the ninth embodiment shown, the main difference is that it further includes a third cleaning unit that cleans the combustion exhaust gas discharged from the second cleaning unit with a third cleaning liquid and recovers the amine accompanying the combustion exhaust gas. The other configurations are substantially the same as those in the eighth embodiment shown in Figure 9 . It should be noted that Figure 10 in Figure 9 The same parts as those in the eighth embodiment shown are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0167] In this embodiment, as shown in Figure 10 , a third cleaning unit 23 is further accommodated in the absorption tower 20. The third cleaning unit 23 cleans the decarbonized combustion exhaust gas 3 discharged from the second cleaning unit 22 with the third cleaning liquid 13 (or the third cleaning water), and recovers the amine, which is the absorption liquid component accompanying the decarbonized combustion exhaust gas 3. The third cleaning unit 23 is provided above the second cleaning unit 22.

[0168] The third cleaning unit 23 can be the same as Figure 1It is configured in the same manner as the second cleaning unit 22 shown in etc. That is, the third cleaning unit 23 has a cleaning and recovery unit 23a, a cleaning liquid disperser 23b provided above the cleaning and recovery unit 23a, and a third receiving unit 23c provided below the cleaning and recovery unit 23a.

[0169] The cleaning and recovery unit 23a is configured in the form of a countercurrent gas-liquid contact device. As an example, the cleaning and recovery unit 23a includes a cleaning and recovery packing layer 23d. In the third cleaning unit 23, gaseous amine can be effectively recovered, and fog-like amine can also be effectively recovered.

[0170] Connected to the third cleaning unit 23 is a third circulation pipeline 57 for circulating the third cleaning liquid 13. That is, a third circulation pump 58 is provided on the third circulation pipeline 57 to extract the third cleaning liquid 13 stored in the third receiving unit 23c and supply it to the cleaning liquid disperser 23b. Thus, the third cleaning liquid 13 is circulated. A third cleaning liquid cooler 59 for cooling the third cleaning liquid 13 is provided on the third circulation pipeline 57. The third cleaning liquid cooler 59 can be configured in the same manner as the second cleaning liquid cooler 56.

[0171] Thus, according to this embodiment, the decarbonated combustion exhaust gas 3 discharged from the second cleaning unit 22 is cleaned by the third cleaning liquid 13. As a result, the third cleaning unit 23 can mainly recover the gaseous amine accompanying the decarbonated combustion exhaust gas 3. More specifically, in the first cleaning unit 21, the first cleaning liquid 11 can recover fog-like amine and can use the first cleaning liquid 11 that has recovered fog-like amine as the lean solution 5. In the second cleaning unit 22, the second cleaning liquid 12 can recover the fog-like amine not recovered in the first cleaning unit 21 and can also recover gaseous amine. In the third cleaning unit 23, gaseous amine can be mainly recovered. Since the amine concentration of the third cleaning liquid 13 is lower than that of the second cleaning liquid 12, in the third cleaning unit 23, the third cleaning liquid 13 can effectively recover gaseous amine. As a result, the amount of amine discharged into the atmosphere can be further reduced, and the amount of amine discharged to the outside of the carbon dioxide recovery system 1 can be further reduced.

[0172] (The tenth embodiment)

[0173] Next, use Figure 11 to describe the carbon dioxide recovery system and the operation method of the carbon dioxide recovery system in the tenth embodiment of the present invention.

[0174] In Figure 11 the tenth embodiment shown, it is mainly different in that it further has a regeneration cleaning unit that cleans the regeneration exhaust gas discharged from the absorption liquid regeneration unit with the fog of the regeneration cleaning liquid ejected by the regeneration ejector and recovers the amine accompanying the regeneration exhaust gas. Other configurations are the same as those in Figure 1 and Figure 2is substantially the same as the first embodiment shown in. It should be noted that Figure 11 In Figure 1 and Figure 2 Parts that are the same as those in the first embodiment shown in are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0175] In the present embodiment, as Figure 11 shown, the regeneration cleaning unit 37 sprays the condensed water 9 (regeneration cleaning liquid) with the regeneration injector 37f and recovers the amine accompanying the carbon dioxide-containing gas 8 with the mist of the condensed water 9. More specifically, the regeneration cleaning unit 37 has a cleaning and recovery space 37e and a regeneration injector 37f provided above the cleaning and recovery space 37e.

[0176] The cleaning and recovery space 37e is a space provided below the regeneration injector 37f. In the present embodiment, the cleaning and recovery space 37e is a space provided across the first regeneration tower demister 86 from the regeneration injector 37f. In this cleaning and recovery space 37e, the condensed water 9 is sprayed from the regeneration injector 37f. The sprayed condensed water 9 falls freely in the cleaning and recovery space 37e in a mist state (i.e., falls without contacting the surface of structures in the space) while contacting the rising carbon dioxide-containing gas 8. Thereby, the amine accompanying the carbon dioxide-containing gas 8 is recovered. In the regeneration cleaning unit 37, mist-like amine can be effectively recovered, but gaseous amine can also be effectively recovered.

[0177] In the present embodiment, as described above, a cleaning and recovery space 37e is formed between the regeneration injector 37f and the first regeneration tower demister 86. In the cleaning and recovery space 37e, structures such as a packing layer or a tray for allowing the condensed water 9 to flow on the surface while contacting the carbon dioxide-containing gas 8 are not provided. That is, between the regeneration injector 37f and the first regeneration tower demister 86, structures such as those for allowing the condensed water 9 to flow on the surface are not provided, and the cleaning and recovery space 37e is formed by crossing the first regeneration tower demister 86 from the regeneration injector 37f. Thus, the cleaning and recovery space 37e is configured such that the condensed water 9 contacts the carbon dioxide-containing gas 8 while falling freely. The mist of the condensed water 9 sprayed from the regeneration injector 37f falls in the cleaning and recovery space 37e where the carbon dioxide-containing gas 8 rises and directly reaches the first regeneration tower demister 86. That is, the condensed water 9 after passing through the cleaning and recovery space 37e directly reaches the first regeneration tower demister 86. During the fall, the condensed water 9 contacts the carbon dioxide-containing gas 8, and the mist-like amine accompanying the carbon dioxide-containing gas 8 collides physically with the mist of the condensed water 9 and is recovered.

[0178] The regeneration injector 37f sprays the condensed water 9 toward the cleaning and recovery space 37e to make it fall. The regeneration injector 37f may be configured in the same manner as the first injector 21b or the second injector 22f.

[0179] Thus, according to this embodiment, the condensate 9 is sprayed by the regeneration ejector 37f, and the amine accompanying the carbon dioxide-containing gas 8 is recovered with the mist of the condensate 9. Thus, the mist of the condensate 9 can physically collide with the mist-like amine accompanying the carbon dioxide-containing gas 8 discharged from the amine regeneration section 30a. Therefore, the mist-like amine can be effectively recovered into the condensate 9. In addition, since the amine concentration of the condensate 9 is low, the gaseous amine accompanying the carbon dioxide-containing gas 8 can also be recovered. Therefore, the cleaning efficiency of the carbon dioxide-containing gas 8 can be further improved, and the discharge amount of amine into the atmosphere can be further reduced. In addition, since the amine can be removed from the carbon dioxide-containing gas 8, the purity of carbon dioxide in the carbon dioxide-containing gas can be improved. Therefore, the use of carbon dioxide can be expanded.

[0180] In addition, the regeneration cleaning section 37 based on the above-described embodiment is not limited to being applied to Figure 11 the carbon dioxide recovery system 1 shown, and can be applied to various carbon dioxide recovery systems 1. For example, Figure 11 the regeneration cleaning section 37 shown can also be applied to Figures 3 to 10 the carbon dioxide recovery system 1 shown. In addition, the first cleaning section 21 in the absorption tower 20 is not limited to having a configuration including the first ejector 21b. For example, the first cleaning section 21 may have the same configuration as the Figure 1 second cleaning section 22 shown, or the lean solution 5 may be supplied from a Figure 3 liquid distributor 20b such as that shown to the carbon dioxide recovery section 20a. In this case, the lean solution 5 can be directly supplied from the lean solution pipeline 16 to the liquid distributor 20b, or a Figure 3 bypass pipeline 60 such as that shown can be connected to the liquid distributor 20b.

[0181] According to the embodiment described above, the discharge amount of amine can be reduced.

[0182] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments or their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope. In addition, of course, within the scope of the gist of the present invention, these embodiments can be partially and appropriately combined.

Claims

1. A carbon dioxide recovery system, comprising: A carbon dioxide recovery section that absorbs carbon dioxide contained in combustion exhaust gas into an absorption liquid containing amine; An absorption liquid regeneration section that regenerates the absorption liquid by releasing the carbon dioxide from the absorption liquid discharged from the carbon dioxide recovery section; A first cleaning section that cleans the combustion exhaust gas discharged from the carbon dioxide recovery section with a mist of a first cleaning liquid ejected by a first ejector and recovers the amine accompanying the combustion exhaust gas; The second cleaning unit cleans the combustion exhaust gas discharged from the first cleaning unit with a second cleaning liquid, and recovers the amine accompanying the combustion exhaust gas; And An absorption liquid pipeline that supplies the absorption liquid regenerated in the absorption liquid regeneration section to the first ejector as the first cleaning liquid; The first cleaning liquid ejected by the first ejector is supplied to the carbon dioxide recovery section as the absorption liquid; The first cleaning section has a first receiving section provided below the first ejector for receiving the mist of the first cleaning liquid ejected by the first ejector and a first circulation pipeline for supplying the first cleaning liquid in the first receiving section to the first ejector; The absorption liquid pipeline is connected to the first circulation pipeline; A cleaning liquid distributor capable of distributing the first cleaning liquid to the first ejector and the carbon dioxide recovery section is provided on the first circulation pipeline; The cleaning liquid distributor is arranged on the more downstream side than the connection position of the first circulation pipeline and the absorption liquid pipeline; The cleaning liquid distributor is connected to a cleaning liquid distribution pipeline for supplying the first cleaning liquid to the carbon dioxide recovery section; The cleaning liquid distributor can adjust the supply amount of the first cleaning liquid supplied to the first ejector and the supply amount of the first cleaning liquid supplied to the carbon dioxide recovery section.

2. The carbon dioxide recovery system according to claim 1, wherein The first cleaning section has a first cleaning and recovery space provided below the first ejector, where the mist of the first cleaning liquid ejected by the first ejector freely falls while contacting the combustion exhaust gas.

3. The carbon dioxide recovery system according to claim 1 or 2, wherein A first circulation pump is provided on the first circulation pipeline, The absorption liquid pipeline is connected to a position on the first circulation pipeline more upstream than the first circulation pump.

4. The carbon dioxide recovery system according to claim 1 or 2, wherein, A bypass pipeline for supplying the first cleaning liquid in the first receiving section to the carbon dioxide recovery section is further provided.

5. The carbon dioxide recovery system according to claim 4, wherein, An absorption liquid distributor capable of distributing the absorption liquid to the first circulation pipeline and the carbon dioxide recovery section is provided on the absorption liquid pipeline; The absorption liquid distributor is connected to an absorption liquid distribution pipeline for supplying the absorption liquid to the carbon dioxide recovery section; The absorption liquid distributor can adjust the supply amount of the absorption liquid supplied to the first circulation pipeline and the supply amount of the absorption liquid supplied to the carbon dioxide recovery section.

6. The carbon dioxide recovery system according to claim 5, wherein, An absorption liquid cooler for cooling the absorption liquid supplied from the absorption liquid regeneration section to the carbon dioxide recovery section is further provided; The absorption liquid cooler is provided on the absorption liquid pipeline; The absorption liquid distributor is arranged on the more downstream side than the absorption liquid cooler.

7. The carbon dioxide recovery system according to claim 5, wherein, An absorption liquid cooler for cooling the absorption liquid supplied from the absorption liquid regeneration section to the carbon dioxide recovery section is further provided; The absorption liquid cooler is provided on the absorption liquid distribution pipeline.

8. The carbon dioxide recovery system according to claim 7, wherein, A bypass cooler for cooling the first cleaning liquid is provided on the bypass pipeline.

9. The carbon dioxide recovery system according to claim 1 or 2, wherein, The second cleaning section uses a second ejector to eject the second cleaning liquid and recovers the amine accompanying the combustion exhaust gas with the mist of the second cleaning liquid.

10. The carbon dioxide recovery system according to claim 1 or 2, wherein, Further provided with: A first cleaning section outlet demister, which is provided between the first cleaning section and the second cleaning section, and captures the mist of the first cleaning liquid accompanying the combustion exhaust gas discharged from the first cleaning section, and A second cleaning section outlet demister, which captures the mist accompanying the combustion exhaust gas discharged from the second cleaning section; The first cleaning section outlet demister is formed more sparsely than the second cleaning section outlet demister.

11. The carbon dioxide recovery system according to claim 1 or 2, wherein, Further provided with a cleaning liquid mist recovery section, which is provided between the first cleaning section and the second cleaning section, and recovers the mist of the first cleaning liquid accompanying the combustion exhaust gas discharged from the first cleaning section, The cleaning liquid mist recovery section has a mist recovery packing layer for recovering the mist of the first cleaning liquid.

12. The carbon dioxide recovery system according to claim 1 or 2, wherein, Further provided with a third cleaning section, which cleans the combustion exhaust gas discharged from the second cleaning section with a third cleaning liquid and recovers the amine accompanying the combustion exhaust gas.

13. The carbon dioxide recovery system according to claim 1 or 2, wherein, Further provided with a regeneration cleaning section, The absorbent regeneration section discharges the regeneration exhaust gas containing the carbon dioxide, The regeneration cleaning section cleans the regeneration exhaust gas discharged from the absorbent regeneration section with the mist of the regeneration cleaning liquid ejected by the regeneration ejector and recovers the amine accompanying the regeneration exhaust gas.

14. An operation method of a carbon dioxide recovery system, comprising: A step of absorbing carbon dioxide contained in the combustion exhaust gas into an absorbent containing amine in the carbon dioxide recovery section; A step of regenerating the absorbent by releasing the carbon dioxide from the absorbent discharged from the carbon dioxide recovery section; A step of cleaning the combustion exhaust gas discharged from the carbon dioxide recovery section with the mist of the first cleaning liquid ejected from the first ejector in the first cleaning section and recovering the amine accompanying the combustion exhaust gas; and A step of cleaning the combustion exhaust gas discharged from the first cleaning section with the second cleaning liquid and recovering the amine accompanying the combustion exhaust gas; In the step of regenerating the absorbent, the regenerated absorbent is supplied to the first ejector through the absorbent pipeline as the first cleaning liquid; The first cleaning liquid ejected by the first ejector is supplied to the carbon dioxide recovery section as the absorbent; The first cleaning section has a first receiving section provided below the first ejector for receiving the mist of the first cleaning liquid ejected from the first ejector and a first circulation pipeline for supplying the first cleaning liquid in the first receiving section to the first ejector; The absorbent pipeline is connected to the first circulation pipeline; A cleaning liquid distributor capable of distributing the first cleaning liquid to the first ejector and the carbon dioxide recovery section is provided on the first circulation pipeline; The cleaning liquid distributor is arranged on the more downstream side than the connection position of the first circulation pipeline and the absorbent pipeline; The cleaning liquid dispenser is connected to a cleaning liquid distribution pipeline that supplies the first cleaning liquid to the carbon dioxide recovery section; The cleaning liquid dispenser is capable of adjusting the supply amount of the first cleaning liquid supplied to the first ejector and the supply amount of the first cleaning liquid supplied to the carbon dioxide recovery section.

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