Cooling tower, carbon dioxide recovery device, and method for processing surface of filler

Abstract

A cooling tower that cools exhaust gas, the cooling tower comprising: a body portion through the interior of which the exhaust gas can flow; a filler that is provided inside the body portion and cools the exhaust gas flowing through the body portion; a circulation part that has a circulation flow path for pumping up cooling water stored below the body portion and circulating the cooling water to above the body portion; a liquid dispersion part that is connected to the circulation flow path above the body portion and supplies the cooling water to the filler from above the filler; and a supply part that supplies a roughening material for roughening the surface of the filler to the interior of the body portion.

Description

Cooling Tower, Carbon Dioxide Recovery Device, and Method for Surface Treatment of Filling Material

[0001] The present disclosure relates to a cooling tower, a carbon dioxide recovery device, and a method for surface treatment of a filling material. This application claims priority to U.S. Application No. 19 / 055,636, filed on February 18, 2025, the content of which is incorporated herein by reference.

[0002] A carbon dioxide recovery device that removes and recovers carbon dioxide from exhaust gas includes a cooling tower that cools the exhaust gas, an absorption tower that absorbs and recovers carbon dioxide contained in the cooled exhaust gas into an absorption liquid, and a regeneration tower that separates and regenerates carbon dioxide from the absorption liquid that has absorbed carbon dioxide. The absorption tower is provided inside with a gas-liquid contact plate and a nozzle that sprays the absorption liquid onto the gas-liquid contact plate. The absorption efficiency of carbon dioxide depends on the contact area between the exhaust gas and the absorption liquid. Therefore, in order to increase the absorption efficiency, it is desirable to use a material with high surface wettability and easy spreading of the absorption liquid for the gas-liquid contact plate. Conventionally, a metal material with good wettability to an aqueous solution has been used as the material of the gas-liquid contact plate. Further, Patent Document 1 describes a process (such as a blasting process) for roughening the surface of a metal gas-liquid contact plate to improve the wettability of the gas-liquid contact plate.

[0003] Since a metal gas-liquid contact plate is heavy, the structure that supports the gas-liquid contact plate becomes large. Therefore, it is conceivable to use a resin material lighter than the metal material for the gas-liquid contact plate. Generally, resins are hydrophobic. For this reason, Patent Document 2 discloses a method of performing surface treatment to increase the wettability of a resin gas-liquid contact plate and then installing it in the tower.

[0004] Japanese Patent No. 7047273 Japanese Patent No. 5794775

[0005] The cooling tower of a carbon dioxide capture system has a packing material inside, and the exhaust gas is cooled by the gas-liquid contact between the packing material and cooling water sprayed onto it. For cooling towers as well, the larger the contact area between the exhaust gas and the cooling water, that is, the higher the wettability of the packing material, the higher the cooling efficiency. However, conventional technology required an additional step of surface treatment of the packing material before installing the cooling tower. Furthermore, if the wettability decreased during operation, the system had to be shut down and the packing material replaced.

[0006] This disclosure provides a carbon dioxide recovery device that can perform surface treatment to improve the wettability of the packing material after installation in a cooling tower, and a method for surface treatment of the packing material.

[0007] According to one aspect of the present disclosure, a cooling tower is a cooling tower for cooling exhaust gas, comprising: a circulation section having a packing material for cooling the exhaust gas flowing inside the cooling tower; a circulation channel for pumping up cooling water stored below the cooling tower and circulating it to the upper part of the cooling tower; and a heat exchanger for cooling the cooling water flowing through the circulation channel; a liquid dispersion section connected to the circulation channel above the cooling tower and supplying the cooling water to the packing material from above; and a supply section supplying a surface roughening material to roughen the surface of the packing material inside the cooling tower.

[0008] According to one aspect of the present disclosure, the carbon dioxide recovery apparatus comprises a cooling tower, an absorption tower that removes carbon dioxide contained in the exhaust gas cooled by the cooling tower by absorbing it into an absorbent liquid, and a regeneration tower that regenerates the absorbent liquid by separating the carbon dioxide from the absorbent liquid discharged from the absorption tower.

[0009] According to one aspect of the present disclosure, a surface treatment method for a packing material of a cooling tower for cooling exhaust gas includes the steps of: cooling the exhaust gas flowing inside the cooling tower with the packing material; pumping up cooling water stored below the cooling tower and circulating it to the upper part of the cooling tower through a circulation channel, and cooling the cooling water flowing through the circulation channel with a heat exchanger; supplying the cooling water from above to the packing material from a liquid dispersion unit connected to the circulation channel above the cooling tower; and supplying a surface roughening material to the inside of the cooling tower to roughen the surface of the packing material.

[0010] According to the above-described embodiment, surface treatment can be performed to improve the wettability of the packing material after it has been installed in the cooling tower.

[0011] This is a schematic diagram showing the overall configuration of a carbon dioxide recovery system according to the first embodiment of this disclosure. This is a schematic diagram showing the configuration of a cooling tower according to the first embodiment of this disclosure. This is a first flowchart showing an example of surface treatment according to the first embodiment of this disclosure. This is a second flowchart showing an example of surface treatment according to the first embodiment of this disclosure. This is a schematic diagram showing the configuration of a cooling tower according to the second embodiment of this disclosure. This is a schematic diagram showing the configuration of a cooling tower according to the third embodiment of this disclosure. This is a schematic block diagram showing the configuration of a control unit computer according to at least one embodiment.

[0012] <First Embodiment> The carbon dioxide capture system according to the first embodiment of this disclosure will be described in detail below with reference to Figures 1 to 4.

[0013] (Overall Configuration of the Carbon Dioxide Recovery System) Figure 1 is a schematic diagram showing the overall configuration of a carbon dioxide recovery system according to the first embodiment of the present disclosure. The carbon dioxide recovery system 100 recovers carbon dioxide from exhaust gas G1 emitted by the combustion equipment 10. The combustion equipment 10 is equipment that burns fuel and air to emit exhaust gas G1, and can be any type, such as a boiler, incinerator, or gas turbine. The carbon dioxide recovery system 100 includes a dust collector 2, a desulfurization device 3, and a carbon dioxide recovery device 4. The dust collector 2 and the desulfurization device 3 can be installed only when necessary depending on the properties of the exhaust gas G1, and can be omitted. In other words, the configuration of the carbon dioxide recovery system 100 may be changed according to the combustion equipment 10.

[0014] The dust collector 2 is installed downstream of the combustion equipment 10. The dust collector 2 removes soot and other particles contained in the exhaust gas G1. The dust collector 2 is, for example, a dry electrostatic precipitator (ESP) or a bag filter.

[0015] The desulfurization unit 3 is installed downstream of the dust collector 2. The desulfurization unit 3 removes sulfur oxides (SOx) contained in the exhaust gas G1.

[0016] The carbon dioxide recovery unit 4 is installed downstream of the desulfurization unit 3. The carbon dioxide recovery unit 4 comprises a cooling tower 5, an absorption tower 6, and a regeneration tower 7. The cooling tower 5 cools the exhaust gas G1. The absorption tower 6 removes the carbon dioxide contained in the exhaust gas G1 cooled by the cooling tower 5 by absorbing it into an absorbent liquid. The absorption tower 6 discharges the purified gas G2, from which carbon dioxide has been removed, to the outside of the system (atmosphere) and also discharges the absorbent liquid that has absorbed carbon dioxide to the regeneration tower 7. The regeneration tower 7 separates carbon dioxide from the absorbent liquid discharged by the absorption tower 6 and regenerates the absorbent liquid. The regeneration tower 7 returns the regenerated absorbent liquid to the absorption tower 6 and discharges the separated carbon dioxide to the outside of the system. The carbon dioxide discharged from the regeneration tower 7 is stored in a recovery tank or the like and used in other systems.

[0017] (Cooling Tower Configuration) Figure 2 is a schematic diagram showing the configuration of a cooling tower according to the first embodiment of the present disclosure. As shown in Figure 2, the cooling tower 5 comprises a main body 50, a packing material 51, a circulation unit 52, a liquid dispersion unit 53, a supply unit 54, a recovery unit 55, and a control unit 56.

[0018] The main body 50 is a hollow container extending vertically, through which exhaust gas G1 flows vertically. Below the main body 50 (upstream in the direction of exhaust gas G1 flow), an exhaust gas introduction channel 50A is connected to introduce the exhaust gas G1, which has been processed by the dust collector 2 and the desulfurization device 3, into the main body 50. Above the main body 50 (downstream in the direction of exhaust gas G1 flow), an exhaust gas discharge channel 50B is connected to discharge the exhaust gas G1, which has been cooled inside the main body 50, to the absorption tower 6. A blower (not shown) is provided between the cooling tower 5 and the absorption tower 6 (downstream of the exhaust gas discharge channel 50B), and the blower draws the exhaust gas into the absorption tower 6. Below the main body 50, cooling water for the exhaust gas G1 is stored. This cooling water is condensed water produced when the water contained in the exhaust gas G1 is cooled. Furthermore, when exhaust gas G1 is not introduced, such as during the trial operation of the cooling tower 5, water introduced from an external source may be used as cooling water. In addition, the main body 50 is equipped with sensors such as a thermometer 501 for measuring the temperature of the exhaust gas G1 discharged from the main body 50 and a liquid level gauge 502 for measuring the liquid level of the cooling water.

[0019] The filler 51 is provided inside the main body 50. The filler 51 is made of, for example, a resin material.

[0020] The circulation unit 52 uses a pump 522 to draw up the cooling water stored below the main body 50 and circulates it as cooling water above the main body 50 through the circulation channel 521. A heat exchanger 523 is provided in the circulation channel 521 to cool the cooling water drawn up by the pump 522. The lower part of the circulation channel 521 is the upstream side in the direction of cooling water flow, and the upper part is the downstream side in the direction of cooling water flow. The circulation unit 52 also monitors the value measured by the liquid level gauge 502, and when the amount of cooling water stored in the main body 50 exceeds a certain amount, the control unit 56 controls the opening of the adjustment valve 526 to drain a portion of the cooling water flowing through the circulation channel 521 through the drain channel 525. Although Figure 2 shows an example in which the drain channel 525 branches off from the circulation channel 521 on the upstream side of the recovery unit 55 (described later), the drain channel 525 may also branch off from the circulation channel 521 on the downstream side of the recovery unit 55 (on the upstream side of the heat exchanger 523).

[0021] The liquid dispersion unit 53 is located above the main body 50 and connected to the outlet of the circulation channel 521. The liquid dispersion unit 53 is positioned above the packing material 51 and supplies cooling water cooled by the circulation unit 52 to the packing material 51. As a result, the cooling water supplied from the liquid dispersion unit 53 flows from above to below the packing material 51. The exhaust gas G1 flowing from below to above the main body 50 is cooled by gas-liquid contact with the cooling water flowing over the packing material 51. The liquid dispersion unit 53 can be any type, such as a spray-type liquid disperser, a trough-type liquid disperser, a channel-type liquid disperser, an element-type liquid disperser, or a tubular-type liquid disperser.

[0022] The supply unit 54 supplies a surface roughening material to the interior of the main body 50 to roughen the surface of the filler material 51. In this embodiment, powder M1 is used as the surface roughening material. For example, soot (a granular material containing coal ash, etc.) collected by the dust collector 2 is reused as powder M1. Alternatively, instead of soot collected by the dust collector 2, granular materials such as limestone, mica, quartz, or silicon dioxide may be purchased and used as powder M1.

[0023] The supply unit 54 includes a supply line 541 and a control valve 542. The supply line 541 may be connected near the connection point between the exhaust gas introduction passage 50A and the main body 50, as shown in the example in Figure 2, or it may be connected directly to the main body 50. The control valve 542 opens and closes according to the control of the control unit 56 to start or stop the supply of powder M1. In addition, the amount of powder M1 supplied can be increased or decreased by changing the opening degree of the control valve 542 according to the control of the control unit 56.

[0024] The powder M1 flows into the lower part of the main body 50 along with the exhaust gas G1 through the supply line 541. As described above, a blower (not shown) installed between the cooling tower 5 and the absorption tower 6 draws the exhaust gas G1 discharged from the cooling tower 5 into the absorption tower 6. Therefore, the pressure inside the main body 50 of the cooling tower 5 is lower than that inside the supply line 541, which is atmospheric pressure, so the supply unit 54 uses this pressure difference to inject the powder M1 from the supply line 541 into the main body 50.

[0025] The powder M1 that flows into the main body 50 flows upward through the inside of the main body 50 together with the exhaust gas G1 and adheres to the surface of the filler material 51. The powder M1 adhering to the filler material 51 is mixed with the cooling water supplied from the liquid dispersion unit 53 to form a slurry. The slurry flows over the surface of the filler material 51, roughening (grinding) the surface of the filler material 51. Alternatively, the powder M1 adheres to the surface of the filler material 51, roughening the surface of the filler material 51. When the surface of the filler material 51 is roughened, the wettability improves and the cooling capacity increases.

[0026] The recovery unit 55 filters the cooling water flowing through the circulation channel 521 to recover the powder M1 from the cooling water. The recovery unit 55 is a filter system with an automatic backwashing function or an auto-strainer. In this embodiment, the recovery unit 55 is provided in a branch channel 524 that branches off from the circulation channel 521 and filters the cooling water flowing through the circulation channel 521. The cooling water filtered by the recovery unit 55 (cooling water that does not contain powder M1) is discharged out of the system through the branch channel 524. On the other hand, the cooling water containing powder M1 is returned to the circulation channel 521 and supplied by the liquid dispersion unit 53 to be reused in a process that roughens the surface of the packing material 51. The particle size of the recovered powder M1 may be adjusted by modifying the filter material of the recovery unit 55. That is, it is possible to select a filter material for the recovery unit 55 that allows powder M1 of a certain particle size or smaller to pass through. In this way, powder M1 with a particle size that contributes little to improving the surface roughness of the filler material is discharged out of the system through the branched channel 524, thereby further suppressing the impact of powder M1 on the pump 522 and heat exchanger 523.

[0027] The control unit 56 controls the surface treatment of the packing material 51. During the trial run before starting normal operation of the cooling tower 5, the control unit 56 controls the adjustment valve 542 of the supply unit 54 to allow the powder M1 to flow into the main body 50 and perform a surface treatment to roughen the surface of the packing material 51. In addition, during the normal operation of the cooling tower 5, the control unit 56 may, if necessary, control the adjustment valve 542 of the supply unit 54 to allow the powder M1 to flow into the main body 50 and perform further surface treatment of the packing material 51.

[0028] Furthermore, as shown in the example in Figure 2, if the dust collector 2 has multiple dust collection units 21 and each dust collection unit 21 is capable of collecting powder M1 (soot) of different particle sizes, a powder M1 of an appropriate particle size may be selected and supplied to the main unit 50 according to the material of the packing material 51, etc. For example, the dust collection units 21 have dust collection units 21A, 21B, and 21C in order from the upstream side in the flow direction of the exhaust gas G1. The dust collection unit 21A on the upstream side collects powder M1 with a larger particle size. The soot collected by the dust collection units 21A, 21B, and 21C is swept off and accumulated in the corresponding hoppers 22A, 22B, and 22C. That is, powder M1 of different particle sizes is accumulated in each hopper 22A, 22B, and 22C. The supply line 541 of the supply unit 54 is connected to the hopper 22 where the powder M1 of the selected particle size is accumulated. For example, to roughen the surface of the filler 51, it may be more effective to use a powder M1 with a larger particle size. In this case, the supply line 541 is connected to the upstream hopper 22A where the powder M1 with a larger particle size is accumulated. Also, depending on the material of the filler 51, it may be more effective to use a powder M1 with a smaller particle size. In this case, the supply line 541 is connected to the downstream hopper 22B or 22C where the powder M1 with a smaller particle size is accumulated.

[0029] Furthermore, as shown in the example in Figure 2, the supply line 541 may be connected to each hopper 22A, 22B, 22C via on-off valves 23A, 23B, 23C, and the control unit 56 may select powder M1 of any particle size by switching the open / closed state of the on-off valves 23. In the example in Figure 2, the control unit 56 opens the upstream on-off valve 23A and closes the other on-off valves 23B, 23C so that powder M1 with a large particle size is used. Note that the configuration in Figure 2 is just one example, and the number of dust collection units 21, hoppers 22, and on-off valves 23 in the dust collector 2 may be changed as needed.

[0030] (Surface treatment of packing material 1) Figure 3 is a first flowchart showing an example of surface treatment according to the first embodiment of the present disclosure. Here, a method is described in which the control unit 56 performs surface treatment on the packing material 51 before starting normal operation of the cooling tower 5. For example, the control unit 56 performs the surface treatment shown in Figure 3 during trial operation when the cooling tower 5 is newly installed, or during trial operation when maintaining the cooling tower 5 that is in operation. Note that the combustion equipment 10 may not be operated during trial operation, so cooling water is supplied to the cooling tower 5 from the outside. During trial operation when the cooling tower 5 is newly installed, soot (powder M1) may not have been collected by the dust collector 2. In that case, soot recovered from another dust collector or granular material such as purchased limestone is used as powder M1. During trial operation during maintenance, soot collected by the dust collector 2 before maintenance may be used as powder M1.

[0031] First, the control unit 56 receives an instruction to start the surface treatment (step S101). For example, the control unit 56 receives an input operation for a start instruction from a worker who installs or maintains the carbon dioxide recovery device 4.

[0032] Upon receiving an instruction to start surface treatment, the control unit 56 operates the pump 522 to circulate cooling water in the circulation unit 52 (step S102), and causes the liquid dispersion unit 53 to supply the cooling water pumped up by the pump 522 to the main body 50 (step S103). Then, the control unit 56 controls the adjustment valve 542 of the supply unit 54 to open, and starts supplying powder M1 to the main body 50 (step S104). At this time, the control unit 56 controls the opening degree of the adjustment valve 542 according to the material of the filler 51, etc., and adjusts the amount of powder M1 supplied. At this time, it is desirable for the control unit 56 to adjust the amount of powder M1 supplied so as not to exceed the allowable range of the pump 522.

[0033] The powder M1 is drawn into the main body 50 by the pressure difference created by the blower (not shown) and adheres to the surface of the filler material 51. The powder M1 adhering to the filler material 51 is mixed with the cooling water supplied from the liquid dispersion unit 53 to form a slurry. The slurry flows over the surface of the filler material 51, roughening (grinding) the surface of the filler material 51. Alternatively, the powder M1 adheres to the surface of the filler material 51, roughening the surface of the filler material 51. After the supply of powder M1 begins, the powder M1 contained in the cooling water stored below the main body 50 is filtered by the recovery unit 55. The filtered cooling water without powder M1 is drained from the branch channel 524, and the cooling water containing powder M1 is returned to the circulation channel 521. The cooling water containing powder M1 returned to the circulation channel 521 is supplied into the main body 50 by the liquid dispersion unit 53 and reused to roughen the surface of the filler material 51.

[0034] Next, the control unit 56 determines whether the surface treatment of the filler 51 is complete (step S105). For example, the control unit 56 determines that the surface treatment is complete when the time spent in trial operation while supplying powder M1 exceeds a predetermined treatment time. The treatment time is set by measuring the time required for roughening through prior tests or simulations. Note that different treatment times may be set for each combination of parameters such as the material of the filler 51 and powder M1, and the flow rate of powder M1. The control unit 56 may also accept a specification of the treatment time from the operator in step S101. Alternatively, the control unit 56 may determine that the surface treatment is complete when it receives an input operation from the operator indicating the end of the surface treatment.

[0035] If the control unit 56 determines that the surface treatment is not yet complete (step S105; NO), it returns to step S102 and continues the surface treatment. On the other hand, if the control unit 56 determines that the surface treatment is complete (step S105; YES), it controls the adjustment valve 542 of the supply unit 54 to close, stopping the supply of powder M1 to the main unit 50 (step S106). At this time, if it is OK to end the trial run, the circulation and supply of cooling water are also stopped. After this, the cooling water and powder M1 supplied to the main unit 50 are discharged out of the system through the drainage channel 525 when the control unit 56 opens the adjustment valve 526.

[0036] In this way, by supplying powder M1 during trial operation after a new cooling tower 5 is installed or during maintenance of the cooling tower 5, the surface treatment (roughening) of the packing material 51 can be performed while the packing material 51 is attached to the cooling tower 5 and in parallel with the trial operation. Therefore, there is no need to add a surface treatment process during the manufacturing of the packing material 51, which reduces manufacturing time and costs. In addition, there is no need to remove the packing material 51, perform surface treatment, and then reinstall the packing material 51 during maintenance, which reduces maintenance effort and costs.

[0037] (Surface treatment of the packing material 2) Figure 4 is a second flowchart showing an example of surface treatment according to the first embodiment of the present disclosure. Here, a method is described in which the control unit 56 performs surface treatment of the packing material 51 during the normal operation of the cooling tower 5. During the normal operation of the cooling tower 5, the control unit 56 keeps the adjustment valve 542 of the supply unit 54 closed and does not perform surface treatment of the packing material 51. However, the control unit 56 performs surface treatment of the packing material 51 when the surface roughness of the packing material 51 decreases and the cooling capacity decreases. During this time, it is assumed that the circulation and supply of cooling water by the circulation unit 52 and the liquid dispersion unit 53 (the same process as steps S102 to S103 in Figure 3) is always performed.

[0038] Specifically, the control unit 56 monitors the readings of the thermometer 501 and determines whether the temperature of the exhaust gas G1 discharged from the cooling tower 5 is below the upper limit (step S201). If the temperature of the exhaust gas G1 is below the upper limit (step S201; NO), the control unit 56 determines that the cooling capacity of the packing material 51 has not decreased and terminates the process. On the other hand, if the temperature of the exhaust gas G1 is above the upper limit (step S201; YES), the control unit 56 determines that the cooling capacity of the packing material 51 has decreased. In this case, the control unit 56 controls the adjustment valve 542 of the supply unit 54 to open and starts supplying powder M1 to the main unit 50 (step S202). At this time, the control unit 56 controls the opening degree of the adjustment valve 542 according to the flow rate of the exhaust gas G1 and the material of the packing material 51, and adjusts the amount of powder M1 supplied. As a result, the slurry formed by mixing the powder M1 and cooling water roughens the surface of the packing material 51. Furthermore, after the supply of powder M1 begins, the powder M1 contained in the cooling water stored below the main body 50 is filtered by the recovery unit 55. The filtered cooling water that does not contain powder M1 is drained from the branch channel 524, and the cooling water containing powder M1 is returned to the circulation channel 521. The cooling water containing powder M1 that is returned to the circulation channel 521 is supplied into the main body 50 by the liquid dispersion unit 53 and reused for roughening the surface of the packing material 51.

[0039] Next, the control unit 56 determines whether the temperature of the exhaust gas G1 discharged from the cooling tower 5 has fallen below the upper limit (step S203). If the temperature of the exhaust gas G1 is above the upper limit (step S203; NO), the control unit 56 continues to supply the powder M1. On the other hand, if the temperature of the exhaust gas G1 falls below the upper limit (step S203; YES), the control unit 56 determines that the surface roughness of the packing material 51 has improved and the cooling capacity has improved. In this case, the control unit 56 controls the adjustment valve 542 of the supply unit 54 to close, stopping the supply of powder M1 to the main unit 50 (step S204). After this, the cooling water and powder M1 supplied to the main unit 50 are discharged out of the system through the drainage channel 525 when the control unit 56 opens the adjustment valve 526.

[0040] The control unit 56 repeatedly performs the process shown in Figure 4 at predetermined intervals during the normal operation of the cooling tower 5. In this way, if the surface roughness of the packing material 51 decreases and the cooling capacity decreases, the control unit 56 can improve the surface roughness of the packing material 51 and restore the cooling capacity without stopping the operation of the cooling tower 5. Furthermore, if the roughness of the packing material 51 is sufficiently high (the exhaust gas temperature can be maintained below the upper limit), the supply of powder M1 can be stopped, thereby minimizing the impact of powder M1 on wear and performance degradation of various parts of the cooling tower 5 (e.g., the pump 522, etc.).

[0041] (Effects) As described above, the cooling tower 5 according to this embodiment includes a circulation section 52 having a packing material 51 that cools the exhaust gas G1 flowing through the cooling tower 5 (main body 50), a circulation passage 521 that pumps up the cooling water stored below the cooling tower 5 with a pump 522 and circulates it to the upper part of the cooling tower 5, and a heat exchanger 523 that cools the cooling water flowing through the circulation passage 521, a liquid dispersion section 53 that is connected to the circulation passage 521 above the cooling tower 5 and supplies cooling water to the packing material 51 from above, and a supply section 54 that supplies a roughening material (powder M1) to roughen the surface of the packing material 51 inside the cooling tower 5.

[0042] With this configuration, for example, after installing the cooling tower 5, by operating the cooling tower 5 (normal operation or trial operation) while supplying powder M1, the packing material 51 can be roughened and its wettability improved while it is attached to the cooling tower 5. Therefore, there is no need to add a surface treatment process during the manufacturing of the packing material 51, thus reducing manufacturing time and costs. In addition, there is no need to remove the packing material 51 during maintenance, perform surface treatment, and then reinstall the packing material 51, thus reducing maintenance effort and costs.

[0043] Furthermore, the cooling tower 5 is equipped with a control unit 56 that supplies powder M1 to the supply unit 54 to roughen the surface of the packing material 51 before normal operation of the cooling tower 5, and stops supplying powder M1 to the supply unit 54 during normal operation of the cooling tower 5.

[0044] By doing so, during the test run before the normal operation of the cooling tower 5, it is possible to perform a surface treatment that roughens the packing material 51 to enhance the wettability. Also, during normal operation, by stopping the supply of the powder M1, the influence of the powder M1 on each part (such as the pump 522, etc.) of the cooling tower 5 can be minimized.

[0045] Further, when the temperature of the exhaust gas G1 discharged from the cooling tower 5 (main body part 50) is equal to or higher than the upper limit value during the normal operation of the cooling tower 5, the control unit 56 causes the supply unit 54 to supply the powder M1.

[0046] By doing so, when the roughness of the surface of the packing material 51 washed away by the cooling water during the normal operation of the cooling tower 5 decreases, the cooling tower 5 can improve the roughness of the surface of the packing material 51 without stopping the operation of the cooling tower 5, improve the wettability, and recover the cooling capacity.

[0047] Further, the cooling tower 5 further includes a recovery unit 55 that recovers the powder M1 contained in the cooling water flowing through the circulation flow path 521 and can re-add the recovered powder M1 to the circulation flow path 521.

[0048] By doing so, the cooling tower 5 can, as necessary, return the powder M1 recovered from the cooling water to the circulation flow path 521 and reuse it as a roughening material for roughening the packing material 51.

[0049] Also, the roughening material is the powder M1 (dust) collected by the dust collector 2 provided upstream of the cooling tower 5.

[0050] By doing so, the cooling tower 5 can effectively utilize the dust collected by the dust collector 2 to perform a surface treatment for improving the roughness of the surface of the packing material 51. Thereby, it is not necessary to separately prepare a roughening material for the surface treatment of the packing material 51, and the cost required for the surface treatment can be reduced.

[0051] Also, the dust collector 2 has a plurality of dust collection parts 21 that collect powders of different particle sizes, and the roughening material is the powder M1 collected by any one of the dust collection parts 21 of the dust collector 2.

[0052] In this way, the cooling tower 5 can use powder M1 of an appropriate particle size depending on the material of the packing material 51. This allows for efficient surface treatment of the packing material 51.

[0053] <Modification of the First Embodiment> In the first embodiment, the supply unit 54 consisted of a supply line 541 and a control valve 542, and an example was described in which the powder M1 collected by the dust collector 2 was supplied to the main unit 50 separately from the exhaust gas G1. However, the embodiment is not limited to this. For example, in this modification, the dust collector 2 functions as the supply unit 54. In this case, the supply line 541 and the control valve 542 may be omitted.

[0054] Furthermore, in step S104 in Figure 3 and step S202 in Figure 4, the control unit 56 reduces the removal rate of powder M1 from the dust collector 2, which is the supply unit 54, so that the exhaust gas G1 is mixed with powder M1 before it flows into the main unit 50. If the dust collector 2 is an electrostatic precipitator, the control unit 56 changes the removal rate of powder M1 by, for example, controlling the charge of the dust collector 2. If the dust collector 2 is a bag filter, the control unit 56 changes the removal rate of powder M1 by, for example, changing the brushing operation. By changing the removal rate of powder M1 in this way, the control unit 56 adjusts the amount of powder M1 that flows into the main unit 50 together with the exhaust gas G1 (supply amount). At this time, it is desirable for the control unit 56 to adjust the supply amount of powder M1 so as not to exceed the allowable range of the pump 522.

[0055] In this way, by using the dust collector 2 as the powder M1 supply unit 54, the configuration for supplying the powder M1 (supply line 541 and control valve 542) can be omitted. This allows the cooling tower 5 to be made more compact.

[0056] <Second Embodiment> Next, the second embodiment will be described in detail with reference to Figure 5. Components common to the above-described embodiment are denoted by the same reference numerals and their detailed descriptions are omitted.

[0057] Figure 5 is a schematic diagram showing the configuration of a cooling tower according to a second embodiment of the present disclosure. As shown in Figure 5, the recovery unit 55 of this embodiment is provided upstream of the heat exchanger 523 in the circulation channel 521. The recovery unit 55 re-adds the recovered powder M1 to the circulation channel 521 through a bypass channel 551 that connects the recovery unit 55 to the circulation channel 521 downstream of the heat exchanger 523.

[0058] In this embodiment, the branch channel 524 (first drainage line) for discharging filtered cooling water outside the system branches off from the circulation channel 521 upstream of the connection point between the circulation channel 521 and the bypass channel 551. The bypass channel 551 is also provided with a branch channel 527 (second drainage line) that can drain the cooling water containing the powder M1 recovered by the recovery unit 55 outside the system.

[0059] In step S104 of Figure 3 and step S202 of Figure 4, while the control unit 56 is supplying powder M1, the powder M1 contained in the cooling water is filtered by the recovery unit 55, and filtered cooling water without powder M1 is introduced into the heat exchanger 523 downstream of the recovery unit 55. The cooling water containing the powder M1 recovered by the recovery unit 55 bypasses the heat exchanger 523 in the bypass channel 551 and is re-added to the circulation channel 521. Multiple filters (filter units) are also provided within the recovery unit 55. The recovery unit 55 can operate a backwashing function to remove powder M1 adhering to each filter. At this time, the control unit 56 may close the valve 528 and re-add the powder M1 removed from the filters by the backwashing function to the circulation channel. Alternatively, the control unit 56 may open the valve 528 provided in the branch channel 527 to discharge the powder M1 removed from the filters by the backwashing function out of the system, thereby reducing the amount of powder M1 re-added to the circulation channel 521. The control unit 56 receives instructions from, for example, an operator and controls the opening and closing of the valve 528. The recovery unit 55 can operate the backwashing function in at least one of the multiple filters while continuing to filter the cooling water with the other filters. In other words, filtered cooling water can always be flowed to the heat exchanger 523 even while the recovery unit 55 is cleaning some of the filters. If it is desired to increase the proportion of roughening material flowing, the filtered cooling water may be drained from the branch channel 524 by opening a valve (not shown). After the control unit 56 stops supplying the powder M1 in step S106 in Figure 3 and step S204 in Figure 4, the cooling water containing the powder M1 may be discharged from the system through the drain channel 525 by opening the adjustment valve 526. Alternatively, the cooling water containing the powder M1 may be discharged from the system through the branch channel 527 by opening the valve 528 instead of the drain channel 525, or it may be discharged from both the drain channel 525 and the branch channel 527. Although the example given shows multiple filters within the recovery unit 55, the configuration is not limited to this and can be modified as appropriate.

[0060] By doing so, the cooling water passing through the heat exchanger 523 will have the powder M1 removed, thus preventing the accumulation of dirt (powder M1) on the heat exchanger 523.

[0061] <Third Embodiment> Next, the third embodiment will be described in detail with reference to Figure 6. Components common to the above embodiments are denoted by the same reference numerals and their detailed descriptions are omitted.

[0062] Figure 6 is a schematic diagram showing the configuration of a cooling tower according to a third embodiment of the present disclosure. As shown in Figure 6, the supply unit 54 of this embodiment further includes a slurry storage tank 543. In this embodiment, slurry M2 stored in the slurry storage tank 543 is used as the surface roughening material. Slurry M2 is, for example, colloidal silica. Depending on the material of the packing material 51, slurry M2 of any particle size may be purchased and used. Alternatively, slurry (circulating water) from the desulfurization unit 3 may be used as slurry M2.

[0063] Thus, by using slurry M2 as the surface roughening material, handling characteristics such as replenishment can be improved compared to powder M1.

[0064] Furthermore, when using commercially available slurry M2, a slurry with an appropriate particle size can be selected according to the material of the filler 51. This effectively roughens the surface of the filler 51 and improves its wettability.

[0065] Figure 6 shows an example in which the configuration of the supply unit 54 in the first embodiment (Figure 2) is replaced with the configuration of the supply unit 54 in the third embodiment, and the slurry M2 is used as a surface roughening material, but the invention is not limited to this. In other embodiments, the configuration of the supply unit 54 in the second embodiment (Figure 5) may be replaced with the configuration of the supply unit 54 in the third embodiment. That is, the configurations of the circulation unit 52 and the recovery unit 55 in the second embodiment are also applicable to the third embodiment.

[0066] <Computer Configuration> Figure 7 is a schematic block diagram showing the configuration of a control unit computer according to at least one embodiment. The computer 900 includes a processor 901, a main memory 902, an auxiliary memory 903, and an interface 904.

[0067] The control unit 56 of the cooling tower 5 described above is implemented in the computer 900. The operation of the control unit 56 described above is stored in auxiliary storage device 903 in the form of a program. The processor 901 reads the program from the auxiliary storage device 903, loads it into the main memory 902, and executes the above processing according to the program. The processor 901 also allocates memory areas in the main memory 902 corresponding to each of the above-mentioned storage units according to the program.

[0068] The program may be for implementing a part of the functions to be performed by the computer 900. For example, the program may perform functions in combination with other programs already stored in the auxiliary storage device 903, or in combination with other programs implemented in other devices. In other embodiments, the computer 900 may be equipped with a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array), etc. In this case, some or all of the functions implemented by the processor 901 may be implemented by the integrated circuit.

[0069] Examples of auxiliary storage devices 903 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. The auxiliary storage device 903 may be an internal media directly connected to the bus of the computer 900, or it may be an external storage device 910 connected to the computer 900 via an interface 904 or a communication line. Furthermore, if this program is distributed to the computer 900 via a communication line, the computer 900 that receives the distribution may expand the program into the main memory 902 and execute the above processing. In at least one embodiment, the auxiliary storage device 903 is a tangible storage medium that is not temporary.

[0070] As described above, several embodiments relating to this disclosure have been explained, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0071] <Note> The cooling tower, carbon dioxide recovery device, and surface treatment method for the packing material described in the above embodiment can be understood, for example, as follows.

[0072] (1) According to the first embodiment, the cooling tower 5 is a cooling tower 5 for cooling exhaust gas G1, and comprises a circulation section 52 having a packing material 51 for cooling the exhaust gas G1 flowing inside the cooling tower 5, a circulation passage 521 for pumping up cooling water stored below the cooling tower 5 with a pump 522 and circulating it to the upper part of the cooling tower 5, and a heat exchanger 523 for cooling the cooling water flowing through the circulation passage 521, a liquid dispersion section 53 connected to the circulation passage 521 above the cooling tower 5 and supplying cooling water to the packing material 51 from above, and a supply section 54 for supplying roughening materials M1 and M2 to roughen the surface of the packing material 51 inside the cooling tower 5.

[0073] With this configuration, for example, after installing the cooling tower 5, by supplying the roughening materials M1 and M2 while operating the cooling tower 5 (normal operation or trial operation), it is possible to perform surface treatment on the packing material 51 to roughen its surface and improve its wettability while the packing material 51 is attached to the cooling tower 5. Therefore, there is no need to add a surface treatment process during the manufacturing of the packing material 51, which reduces manufacturing time and costs. In addition, there is no need to remove the packing material 51, perform surface treatment, and then reinstall the packing material 51 during maintenance, which reduces maintenance effort and costs.

[0074] (2) According to the second embodiment, the cooling tower 5 according to the first embodiment further comprises a control unit 56 that controls the supply unit 54 to supply or stop supplying the roughening materials M1 and M2.

[0075] In this way, the cooling tower 5 can start and stop the supply of the surface roughening materials M1 and M2 as needed.

[0076] (3) According to the third embodiment, the cooling tower 5 according to the second embodiment further includes a control unit 56 that supplies roughening materials M1 and M2 to the supply unit 54 before normal operation of the cooling tower 5 to roughen the surface of the packing material 51, and stops supplying the roughening materials M1 and M2 to the supply unit 54 during normal operation of the cooling tower 5.

[0077] In this way, the cooling tower 5 can undergo surface treatment to roughen the packing material 51 and improve its wettability during the trial run before normal operation. Furthermore, by stopping the supply of the roughening materials M1 and M2 during normal operation, the impact of the roughening materials M1 and M2 on various parts of the cooling tower 5 (such as the pump 522) can be minimized.

[0078] (4) According to the fourth embodiment, in the cooling tower 5 according to the second embodiment, the control unit 56 causes the supply unit 54 to supply roughening materials M1 and M2 when the temperature of the exhaust gas G1 discharged from the cooling tower 5 is above the upper limit during normal operation of the cooling tower 5.

[0079] In this way, if the surface roughness of the packing material 51 decreases due to being washed away by the cooling water during normal operation, the cooling tower 5 can improve the surface roughness of the packing material 51, thereby improving wettability and restoring its cooling capacity without stopping the operation of the cooling tower 5.

[0080] (5) According to the fifth embodiment, in the cooling tower 5 according to the fourth embodiment, the control unit stops supplying the roughening material to the supply unit when the temperature of the exhaust gas discharged from the cooling tower is below the upper limit.

[0081] In this way, when the temperature of the exhaust gas G1 drops below the upper limit, that is, when the wettability of the packing material 51 is restored, the cooling tower 5 stops supplying the roughening materials M1 and M2, thereby suppressing the effect of the roughening materials M1 and M2 on various parts of the cooling tower 5.

[0082] (6) According to the sixth embodiment, the cooling tower 5 according to any one of the first to fifth embodiments further comprises a recovery unit 55 that recovers the roughening materials M1 and M2 contained in the cooling water flowing through the circulation channel 521 and can re-add the recovered roughening materials M1 and M2 to the circulation channel 521.

[0083] In this way, the cooling tower 5 can, if necessary, return the roughening materials M1 and M2 recovered from the cooling water to the circulation channel 521 and reuse them as roughening materials for roughening the packing material 51.

[0084] (7) According to the seventh embodiment, in the cooling tower 5 according to the fourth embodiment, the control unit 56 discharges the roughening materials M1 and M2 recovered by the recovery unit 55 from the cooling water outside the system at least one of the following times: while the roughening materials M1 and M2 are being supplied, and after the supply of the roughening materials M1 and M2 has been stopped.

[0085] In this way, after the cooling tower 5 has finished roughening the packing material 51 and stopped supplying the roughening materials M1 and M2, it can discharge the roughening materials M1 and M2 outside the system so that they do not return to the circulation channel 521. This suppresses the roughening materials M1 and M2 from affecting various parts of the cooling tower 5. In addition, the cooling tower 5 can adjust the amount of roughening materials M1 and M2 supplied to the packing material 51 by discharging the cooling water containing the roughening materials M1 and M2 outside the system while the roughening materials M1 and M2 are being supplied, so that the amount of roughening materials M1 and M2 supplied to the packing material 51 does not become excessive.

[0086] (8) According to the eighth aspect, the cooling tower 5 according to the seventh aspect further comprises a drainage channel 525 that can discharge cooling water out of the system from the upstream side of the recovery section 55 of the circulation channel 521, a first drainage line 524 that discharges the cooled water filtered by the recovery section 55 out of the system, and a second drainage line 527 that discharges the cooled water containing the roughening materials M1 and M2 recovered by the recovery section 55 out of the system, and the control unit 56 adjusts the amount of the roughening materials M1 and M2 to be re-added to the circulation channel 521 by discharging the cooled water containing the roughening materials M1 and M2 out of the system from at least one of the drainage channel 525 and the second drainage line 527, or by discharging the filtered cooled water out of the system from the first drainage line 524.

[0087] In this way, the cooling tower 5 can drain filtered cooling water that does not contain the roughening materials M1 and M2, and cooling water that contains the roughening materials M1 and M2, from separate lines. Furthermore, by draining the filtered cooling water, the cooling tower 5 can increase the amount of roughening materials M1 and M2 re-added to the circulation channel 521, and by draining the cooling water that contains the roughening materials M1 and M2, it can decrease the amount of roughening materials M1 and M2 re-added to the circulation channel 521.

[0088] (9) According to the ninth embodiment, in the cooling tower 5 according to any one of the sixth to eighth embodiments, the recovery unit 55 is provided upstream of the heat exchanger 523 in the circulation channel 521, and the roughening materials M1 and M2 recovered through a bypass channel 551 that bypasses the heat exchanger 523 and connects to the circulation channel 521 are re-added to the circulation channel 521.

[0089] By doing so, the cooling water passing through the heat exchanger 523 will have the surface roughening materials M1 and M2 removed, thus suppressing the adhesion of dirt (surface roughening materials M1 and M2) to the heat exchanger 523.

[0090] (10) According to the tenth embodiment, in the cooling tower 5 according to any one embodiment from the first to the ninth, the roughening material is a powder M1 containing at least one of coal ash, limestone, mica, quartz, or silicon dioxide.

[0091] By using powder M1 corresponding to the material of the filler 51 as a surface roughening material, the filler 51 can be appropriately roughened.

[0092] (11) According to the eleventh embodiment, in a cooling tower 5 according to any one of the first to ninth embodiments, the roughening material is powder M1 collected by a dust collector 2 provided upstream of the cooling tower 5.

[0093] In this way, the cooling tower 5 can effectively utilize the soot collected by the dust collector 2 to perform surface treatment on the packing material 51, thereby improving its surface roughness. This eliminates the need to separately prepare a roughening material for surface treatment of the packing material 51, and reduces the cost required for surface treatment.

[0094] (12) According to the 12th embodiment, in the cooling tower 5 according to the 11th embodiment, the dust collector 2 has a plurality of dust collection units 21 that collect powder M1 of different particle sizes, and the roughening material is the powder M1 collected by any one of the dust collection units 21 of the dust collector 2.

[0095] In this way, the cooling tower 5 can use powder M1 of an appropriate particle size depending on the material of the packing material 51. This allows for efficient surface treatment of the packing material 51.

[0096] (13) According to the 13th embodiment, in a cooling tower 5 according to any one of the first to 9 embodiments, the supply unit 54 is a dust collector 2 provided upstream of the cooling tower 5, which reduces the removal rate of powder M1 contained in the exhaust gas G1 and supplies the powder M1, which is a surface roughening material, into the inside of the cooling tower 5 together with the exhaust gas G1.

[0097] In this way, the cooling tower 5 can effectively utilize the soot collected by the dust collector 2 to perform surface treatment on the packing material 51 to improve its surface roughness. This eliminates the need to separately prepare a roughening material for surface treatment of the packing material 51, thereby reducing the cost required for surface treatment. Furthermore, the cooling tower 5 can omit the components for supplying the powder M1 (supply line 541 and control valve 542). This allows for a more compact configuration of the cooling tower 5.

[0098] (14) According to the 14th embodiment, in the cooling tower 5 according to any one of the first to 9 embodiments, the roughening material is slurry M2.

[0099] Thus, by using slurry M2 as the surface roughening material, handling characteristics such as replenishment can be improved compared to powder M1.

[0100] (15) According to the 15th embodiment, in the cooling tower 5 according to the 14th embodiment, the slurry M2 is the circulating water of the desulfurization unit 3 installed upstream of the cooling tower 5.

[0101] By utilizing the slurry within the carbon dioxide capture system 100 in this way, the need for tanks or other equipment to store the purchased slurry is eliminated, and the cooling tower 5 can be made more space-efficient.

[0102] (16) According to the 16th embodiment, the carbon dioxide recovery device 4 comprises a cooling tower 5 according to any one of the first to 14 embodiments, an absorption tower 6 that removes carbon dioxide contained in the exhaust gas G1 cooled by the cooling tower 5 by absorbing it into an absorbent liquid, and a regeneration tower 7 that regenerates the absorbent liquid by separating carbon dioxide from the absorbent liquid discharged from the absorption tower 6.

[0103] (17) According to the 17th embodiment, a surface treatment method for the packing material 51 of a cooling tower 5 that cools exhaust gas G1 includes the steps of: cooling the exhaust gas G1 flowing inside the cooling tower 5 with the packing material 51; pumping up the cooling water stored below the cooling tower 5 with a pump 522 and circulating it to the upper part of the cooling tower 5 through a circulation channel 521, and cooling the cooling water flowing through the circulation channel 521 with a heat exchanger 523; supplying cooling water to the packing material 51 from above using a liquid dispersion section 53 connected to the circulation channel 521 above the cooling tower 5; and supplying roughening materials M1 and M2 to the inside of the cooling tower 5 to roughen the surface of the packing material 51.

[0104] According to the above-described embodiment, surface treatment can be performed to improve the wettability of the packing material after it has been installed in the cooling tower.

[0105] 100 Carbon Dioxide Recovery System 2 Dust Collector 21, 21A, 21B, 21C Dust Collection Section 22, 22A, 22B, 22C Hopper 23, 23A, 23B, 23C On / Off Valve 3 Desulfurization Equipment 4 Carbon Dioxide Recovery Equipment 5 Cooling Tower 50 Main Body 50A Exhaust Gas Inlet Channel 50B Exhaust Gas Outlet Channel 501 Thermometer 502 Liquid Level Gauge 51 Packing Material 52 Circulation Section 521 Circulation Channel 522 Pump 523 Heat Exchanger 524 Branch Channel (First Drainage Line) 525 Drainage Channel 526 Control Valve 527 Branch Channel (Second Drainage Line) 53 Liquid Dispersion Section 54 Supply Section 541 Supply Line 542 Control Valve 543 Slurry Storage Tank 55 Recovery Section 551 Bypass channel 552 Control valve 56 Control unit 6 Absorption tower 7 Regeneration tower M1 Powder (roughening material) M2 Slurry (roughening material)

Claims

A cooling tower for cooling exhaust gas, A packing material for cooling the exhaust gas flowing inside the cooling tower, A circulation unit having a circulation channel for pumping up cooling water stored below the cooling tower and circulating it to the upper part of the cooling tower, and a heat exchanger for cooling the cooling water flowing through the circulation channel, A liquid dispersion unit connected to the circulation channel above the cooling tower and supplying the cooling water to the packing material from above the packing material, A supply unit that supplies a surface roughening material to roughen the surface of the packing material inside the cooling tower, A cooling tower equipped with a cooling tower. 　 The supply unit further includes a control unit that controls the supply or cessation of the supply of the roughening material. The cooling tower according to claim 1. 　 The control unit supplies the roughening material to the supply unit before normal operation of the cooling tower to roughen the surface of the packing material, and stops supplying the roughening material to the supply unit during normal operation of the cooling tower. The cooling tower according to claim 2. 　 The control unit, during normal operation of the cooling tower, causes the supply unit to supply the surface roughening material when the temperature of the exhaust gas discharged from the cooling tower exceeds the upper limit. The cooling tower according to claim 2. 　 The control unit stops supplying the roughening material to the supply unit when the temperature of the exhaust gas discharged from the cooling tower is below the upper limit. The cooling tower according to claim 4. 　 The system further includes a recovery unit that filters the cooling water flowing through the circulation channel to recover the surface roughening material contained in the cooling water, and allows the recovered surface roughening material to be re-added to the circulation channel. The cooling tower according to claim 2. 　 The control unit, During the supply of the surface roughening material and at least one of the periods after the supply of the surface roughening material is stopped, the cooling water containing the surface roughening material is discharged from the system. The cooling tower according to claim 6. 　 A drainage channel that can discharge the cooling water out of the system from the upstream side of the recovery section of the circulation channel, The recovery unit has a first drainage line (524) from which it can discharge filtered cooling water outside the system, A second drainage line is provided that can discharge the cooling water containing the roughening material recovered by the recovery unit to the outside of the system. Furthermore, The control unit adjusts the amount of the roughening material to be re-added to the circulation channel by discharging the cooling water containing the roughening material from at least one of the drainage channel and the second drainage line, or by discharging filtered cooling water from the first drainage line. The cooling tower according to claim 7. 　 The recovery unit is located upstream of the heat exchanger in the circulation channel and re-adds the roughening material recovered through a bypass channel that bypasses the heat exchanger and connects to the circulation channel back into the circulation channel. The cooling tower according to claim 6. 　 The surface roughening material is a powder containing at least one of coal ash, limestone, mica, quartz, or silicon dioxide. The cooling tower according to claim 1. 　 The surface roughening material is a powder collected by a dust collector installed upstream of the cooling tower. The cooling tower according to claim 1. 　 The dust collector has multiple dust collection sections that collect powders of different particle sizes. The surface roughening material is a powder collected in the dust collection section of any one of the dust collectors. The cooling tower according to claim 11. 　 The supply unit is a dust collector located upstream of the cooling tower, which reduces the removal rate of powder contained in the exhaust gas and supplies the powder, which is the surface roughening material, into the interior of the cooling tower along with the exhaust gas. The cooling tower according to claim 1. 　 The aforementioned surface roughening material is a slurry. The cooling tower according to claim 1. The slurry is the circulating water of a desulfurization device installed upstream of the cooling tower. The cooling tower according to claim 14. 　 The cooling tower according to claim 1, An absorption tower for removing carbon dioxide contained in the exhaust gas cooled by the cooling tower by absorbing it into an absorbent liquid, A regeneration tower for separating carbon dioxide from the absorbent liquid discharged from the absorption tower and regenerating the absorbent liquid, A carbon dioxide capture device equipped with the following features. 　 A method for surface treatment of packing material for a cooling tower that cools exhaust gas, The steps include: cooling the exhaust gas flowing inside the cooling tower with a packing material; The steps include pumping up the cooling water stored at the bottom of the cooling tower and circulating it upwards through a circulation channel, and cooling the cooling water flowing through the circulation channel with a heat exchanger, The liquid dispersion unit, located above the cooling tower and connected to the circulation channel, supplies the cooling water to the packing material from above; The steps include supplying a surface roughening material to the inside of the cooling tower to roughen the surface of the packing material, A surface treatment method for a filler having the following properties.

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