CO2 capture system

Abstract

To provide a CO2 recovery system which is excellent in CO2 emission control effects.SOLUTION: A CO2 recovery system 1 includes a CO2 recovery device 10, a dehydration dryer 20, a high temperature gas supply part 31, and a low temperature gas supply part 32. The CO2 recovery device 10 brings CO2 gas into contact with an aqueous NaOH solution, and produces an aqueous NaHCO3 solution, an aqueous Na2CO3 solution or an aqueous solution containing NaHCO3 and Na2CO3. The dehydration dryer 20 heats the aqueous solution produced by the CO2 recovery device 10 by a heat exchanger 21, and produces NaHCO3, Na2CO3 or a mixture of NaHCO3 and Na2CO3 in the dehydrated and dried states. The high temperature gas supply part 31 supplies CO2 gas of 100°C or higher discharged from a CO2 discharge facility 30 to the heat exchanger 21. The low temperature gas supply part 32 supplies the CO2 gas cooled by the heat exchanger 21 to the CO2 recovery device 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a CO2 capture system. [Background technology]

[0002] In recent years, there has been a demand to reduce emissions of CO2 gas, a greenhouse gas, and various systems for capturing CO2 gas have been studied. For example, Patent Document 1 discloses a CO2 capture system in which CO2-containing exhaust gas from a power generation boiler or the like is reacted with an NaOH aqueous solution to generate NaHCO3 or Na2CO3, and CO2 is then captured from the exhaust gas. The generated NaHCO3 or Na2CO3 is expected to be used as a resource by this CO2 capture system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-288313 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration disclosed in Patent Document 1, taking into consideration the ease of handling when using NaHCO3 or Na2CO3 as a resource, NaHCO3 or Na2CO3 obtained in the form of an aqueous solution is dehydrated and dried in a drying device to form a solid. Furthermore, in the configuration disclosed in Patent Document 1, exhaust gas discharged from a power generation boiler or the like may be at a high temperature. When the high-temperature exhaust gas is brought into contact with an aqueous NaOH solution, the temperature of the aqueous NaOH solution may rise excessively, causing the water in the solution to evaporate, generating water vapor. This water vapor may then be released into the environment. To prevent this, in the configuration disclosed in Patent Document 1, the high-temperature exhaust gas discharged from a power generation boiler or the like is cooled using a cooling device before being brought into contact with an aqueous NaOH solution.

[0005] However, power is usually required to operate the drying device and cooling device disclosed in Patent Document 1. Furthermore, if electricity generated using fossil fuels is used to operate the drying device and cooling device, the CO2 generated to generate the electricity is emitted from the entire system. As a result, the effect of reducing CO2 emissions from the entire system is reduced. Furthermore, if the amount of CO2 emitted from the electricity generated exceeds the amount of CO2 captured by the CO2 capture system, the entire system cannot achieve CO2 emission reduction. In particular, as the system becomes larger, the amount of power consumed by the drying device and cooling device also increases, making it even more difficult to reduce CO2 emissions.

[0006] The present invention has been made in view of the above problems, and aims to provide a CO2 recovery system that is highly effective in suppressing CO2 emissions. [Means for solving the problem]

[0007] One aspect of the present invention is a CO recovery device that contacts CO gas with an aqueous NaOH solution to produce an aqueous NaHCO solution, an aqueous NaCO solution, or an aqueous solution containing NaHCO and NaCO; The aqueous solution produced by the CO2 recovery device a heater into which the aqueous solution is introduced, and Heat exchanger for heating and the aqueous solution is heated by the heat exchanger. a dehydration and drying device for heating the above to produce dehydrated and dried NaHCO3, Na2CO3, or a mixture of NaHCO3 and Na2CO3; a high-temperature gas supply unit that supplies CO2 gas of 100°C or higher discharged from a CO2 emission facility to the heat exchanger; a low-temperature gas supply unit that supplies the CO2 gas cooled by the heat exchanger to the CO2 recovery device. 、 The NaHCO 3 content is calculated based on the weight change of the heater after the aqueous solution is introduced into the heater. 3 , the above Na 2 CO 3 or configured to determine whether dehydration and drying of the mixture is complete; It is in the CO2 capture system. [Effects of the Invention]

[0008] In the CO2 capture system, a CO2 capture device generates an aqueous NaHCO3 solution, an aqueous Na2CO3 solution, or an aqueous solution containing NaHCO3 and Na2CO3 from CO2 gas emitted from a CO2 emission facility. A dehydration / drying device then dehydrates and dries the resulting NaHCO3, Na2CO3, or a mixture of NaHCO3 and Na2CO3. The dehydration / drying device then heats the aqueous solution using CO2 gas at temperatures above 100°C supplied by a high-temperature gas supply unit. The resulting cooled CO2 gas is then supplied to the CO2 capture device by a low-temperature gas supply unit and brought into contact with the aqueous NaOH solution. This configuration eliminates the need for power consumption for either heating the aqueous solution in the dehydration / drying device or lowering the temperature of the CO2 gas for contact with the aqueous NaOH solution. This eliminates the need for fossil fuels for power generation, resulting in a CO2 capture system with excellent CO2 emission reduction effects.

[0009] As described above, according to the above-described embodiment, it is possible to provide a CO2 recovery system that is excellent in the effect of suppressing CO2 emissions. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of a CO2 recovery system according to a first embodiment. [Figure 2] FIG. 2 is a conceptual diagram of a dehydration / drying device and a condensation device in the first embodiment. [Figure 3] FIG. 2 is a flow diagram showing a usage mode of the CO2 recovery system in the first embodiment. [Figure 4] (a) Conceptual diagram of a dehydration and drying device in modified form 1; (b) Conceptual diagram of a dehydration and drying device in modified form 2; [Figure 5] (a) A conceptual diagram of a dehydration and drying device in modified form 3. (b) A conceptual diagram of a longitudinal cross section of a dehydration and drying device in modified form 3. [Figure 6] (a) A conceptual diagram of a dehydration and drying device in modified form 4. (b) A conceptual diagram of a longitudinal cross section of a dehydration and drying device in modified form 4. [Figure 7](a) A conceptual diagram of a dehydration and drying device in modified embodiment 5. (b) A conceptual diagram of a longitudinal cross section of a dehydration and drying device in modified embodiment 5. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment 1) An embodiment of a CO2 recovery system will be described with reference to FIGS. As shown in FIG. 1, the CO 2 recovery system 1 of this embodiment includes a CO 2 recovery device 10, a dehydration and drying device 20, a high-temperature gas supply unit 31, and a low-temperature gas supply unit 32. The CO2 recovery device 10 brings CO2 gas into contact with an aqueous NaOH solution to produce an aqueous NaHCO3 solution, an aqueous Na2CO3 solution, or an aqueous solution containing NaHCO3 and Na2CO3. The dehydration / drying device 20 heats the aqueous solution produced by the CO2 recovery device 10 using a heat exchanger 21 to produce dehydrated and dried NaHCO3, Na2CO3, or a mixture of NaHCO3 and Na2CO3. The high-temperature gas supply unit 31 supplies the CO2 gas of 100°C or higher discharged from the CO2 discharge facility to the heat exchanger 21. The low-temperature gas supply unit 32 supplies the CO2 gas whose temperature has been reduced by the heat exchanger 21 to the CO2 recovery device 10.

[0012] The CO2 recovery system 1 of this embodiment will be described in detail below. The CO2 capture system 1 shown in FIG. 1 is configured to capture CO2 from CO2 gas emitted from a CO2 emission facility 30. In this specification, "CO2 gas" refers to gas containing CO2 as a constituent component. The CO2 gas may be a gas containing only CO2 as a constituent component, or may further contain unavoidable impurities. The CO2 gas may also be a mixed gas containing CO2 and other substances as constituent components. The proportion of CO2 in the mixed gas is not limited, and the main component with the largest proportion in the mixed gas may be CO2 or a substance other than CO2.

[0013] The CO2 emission equipment 30 shown in FIG. 1 is not particularly limited as long as it is an equipment that emits CO2, and examples thereof include equipment with a boiler, a fuel cell, an incinerator, and a heat treatment equipment. A high-temperature gas supply unit 31 is connected to the CO2 emission equipment 30. CO2 gas at 100°C or higher discharged from the CO2 emission equipment 30 flows through the high-temperature gas supply unit 31. In this embodiment, the CO2 gas is exhaust gas containing CO2 discharged from the CO2 emission equipment 30. As described above, the CO2 gas has a temperature of 100°C or higher, and can have a temperature in the range of 100°C to 300°C, for example. In this embodiment, CO2 gas having a temperature of 120°C is used. CO2 gas at 100°C or higher can be supplied to the heat exchanger 21 of the dehydration / drying device 20 (described later) via the high-temperature gas supply unit 31. The temperature of the CO2 gas can be detected by a temperature sensor (not shown) provided in the high-temperature gas supply unit 31.

[0014] As shown in Fig. 1, the high-temperature gas supply unit 31 is connected to the dehydrating / drying device 20. As shown in Fig. 2, the dehydrating / drying device 20 includes a heat exchanger 21, a heating tank 22, an aqueous solution introduction unit 23, a product recovery unit 24, and a water vapor discharge unit 25. In Fig. 2, the left-right direction of the page is defined as a width direction X, and the up-down direction of the page is defined as a height direction Z.

[0015] The heating tank 22 shown in FIG. 2 has a hollow shape. In this first embodiment, the heating tank 22 has a hollow rectangular parallelepiped shape as shown in FIG. 2. The heating tank 22 is provided with an aqueous solution input section 23 that communicates with the interior of the heating tank 22. A NaHCO3 aqueous solution, a Na2CO3 aqueous solution, or an aqueous solution containing NaHCO3 and Na2CO3, generated in the CO2 capture device 10 (described later), is input into the heating tank 22 via the aqueous solution input section 23, as indicated by arrow P1. In this specification, NaHCO3, Na2CO3, and a mixture of the two are collectively referred to as the "product," and the NaHCO3 aqueous solution, the Na2CO3 aqueous solution, or an aqueous solution containing NaHCO3 and Na2CO3, generated in the CO2 capture device 10 (described later), are collectively referred to as the "product aqueous solution." In this embodiment, the aqueous solution input section 23 is provided with a filter 28, which enables removal of foreign matter from the product aqueous solution. The timing of adding the aqueous product solution through the aqueous solution input section 23 is not limited, and the aqueous product solution may be added after the previous aqueous product solution has been dehydrated and dried and the product has been recovered from the heating tank 22, or the aqueous product solution may be added continuously.

[0016] As shown in Fig. 1, the heat exchanger 21 is a pipe connected to the high-temperature gas supply unit 31, and is configured to allow CO2 gas of 100°C or higher supplied from the high-temperature gas supply unit 31 to flow through it. The shape of the heat exchanger 21 is not limited, but in this embodiment, as shown in Fig. 2, the heat exchanger 21 has a shape in which the pipe extends in a planar shape along the bottom of the heating tank 22 so as to contact the bottom of the heating tank 22. Then, as shown by arrow F1, the heat exchanger 21 exchanges heat between CO2 gas of 100°C or higher supplied from the high-temperature gas supply unit 31 to the heat exchanger 21 and the product aqueous solution introduced into the heating tank 22. As a result, the product aqueous solution is heated, and the CO2 gas of 100°C or higher is cooled.

[0017] The heat exchanger 21 shown in FIG. 2 heats the aqueous product solution, evaporating the water and forming a solid product in the heating tank 22. The CO2 gas cooled by the heat exchanger 21 is supplied to the CO2 recovery device 10 via a low-temperature gas supply unit 32, as described below. In this embodiment, the heat exchange in the heat exchanger 21 reduces the temperature of CO2 gas at 100°C or higher to 80°C or lower. This prevents the NaOH aqueous solution from being excessively heated when the CO2 gas is brought into contact with the NaOH aqueous solution, thereby preventing the NaOH aqueous solution from being released into the environment. The temperature of the CO2 gas can be detected by a temperature sensor (not shown) provided in the heat exchanger 21 or the low-temperature gas supply unit 32, described below.

[0018] As shown in FIG. 2, the heating tank 22 is provided with a product recovery section 24. The product recovery section 24 is configured to remove and recover a solid product formed in the heating tank 22 from the heating tank 22. In the first embodiment, the product recovery section 24 is tubular, connected to the lower part of the heating tank 22, and has an openable lid 26 attached to an opening located at the lower end. For example, after a predetermined amount of solid product is obtained in the heating tank 22, the lid 26 can be opened and the product can be dropped from the product recovery section 24 into a recovery container 27 as indicated by arrow P2, thereby removing and recovering the product from the heating tank 22. The recovered products, NaHCO3 and / or Na2CO3, can be used as a resource, for example, as a cleaning agent.

[0019] 2, the heating tank 22 is provided with a water vapor exhaust unit 25. As shown by arrow V1, the water vapor exhaust unit 25 is connected to the heating tank 22 and is configured to be able to exhaust water vapor generated in the heating tank 22 to the outside of the heating tank 22. In the first embodiment, the water vapor exhaust unit 25 is tubular, connected to the upper part of the heating tank 22, and configured to supply water vapor generated in the heating tank 22 to the condenser 40.

[0020] As shown in Fig. 2, the condenser 40 has a water vapor intake section 41 and takes in water vapor supplied from the water vapor discharge section 25 through the water vapor intake section 41. The configuration of the condenser 40 is not limited, and it may be configured to convert water vapor into water, for example, it may have a heat exchanger for cooling the water vapor. In this embodiment, the water vapor taken in by the condenser 40 is cooled by air cooling and converted into water. The water converted by the condenser 40 is discharged from a drain 42 as indicated by arrow R.

[0021] The CO2 recovery device 10 shown in Figure 1 is configured to bring CO2 gas into contact with an aqueous NaOH solution in a reaction vessel 11. In the reaction vessel 11, the reaction of the following formula 1 takes place, followed by the reaction of formula 2: 2NaOH+CO2→ Na2CO3+H2O (Formula 1) Na2CO3+CO2+H2O→ 2NaHCO3 (formula 2)

[0022] 1, before the start of the reaction, neither NaHCO3 nor Na2CO3 is present, but depending on the progress of the reaction, one of the following states occurs: Na2CO3 is produced and no NaHCO3 is present; some Na2CO3 further reacts with CO2 to produce NaHCO3 and both are present; or all Na2CO3 is converted to NaHCO3 and no Na2CO3 remains, and NaHCO3 is present. Both NaHCO3 and Na2CO3 produced by the reaction dissolve in the water in the reaction tank 11 and become aqueous solutions.

[0023] As shown in Figure 1, the reaction vessel 11 is equipped with a low-temperature gas supply unit 32, an exhaust unit 12, a filter 13, an aqueous solution discharge unit 14, and a measurement unit 15. Before the start of the reaction, an aqueous NaOH solution of a predetermined concentration is introduced into the reaction vessel 11. The low-temperature gas supply unit 32 is connected to the reaction vessel 11 and supplies CO2 gas cooled in the heat exchanger 21 to the reaction vessel 11. In this embodiment, the reaction can be started by bubbling the cooled CO2 gas supplied from the low-temperature gas supply unit 32 into contact with the aqueous NaOH solution in the reaction vessel 11.

[0024] 1 contains substances that inhibit the above reaction in the reaction vessel 11, it is preferable to provide a filter that removes the substances that inhibit the above reaction at a position upstream of the reaction vessel 11, such as the high-temperature gas supply unit 31 or the low-temperature gas supply unit 32. However, if the exhaust gas discharged from the CO2 discharge unit 30 does not contain components other than CO2 or if it is clear that it does not contain substances that inhibit the above reaction in the reaction vessel 11, there is no need to provide such a filter.

[0025] 1 discharges the CO2-removed gas, from which CO2 has been removed in the reaction tank 11, from the reaction tank 11 to the outside of the CO2 capture system 1. The exhaust unit 12 is provided with a filter 13, which is configured to capture harmful components in the CO2-removed gas. In the first embodiment, the filter 13 is configured to pass the CO2-removed gas through water to remove water-soluble substances.

[0026] 1 discharges the aqueous product solution generated in the reaction tank 11 from the reaction tank 11. In this embodiment, the aqueous solution discharge part 14 is formed by connecting one end of a tubular member to the CO2 recovery device 10, and the other end of the tubular member is connected to the heating tank 22 to form the aqueous solution input part 23.

[0027] The measuring unit 15 shown in FIG. 1 measures the amount of product produced in the reaction tank 11. While the measurement method used by the measuring unit 15 is not limited, the amount of product produced can be calculated by monitoring changes in the weight of the contents in the reaction tank 11 or changes in pH within the reaction tank 11. The weight change in the contents in the reaction tank 11 can be detected using a weighing scale. Changes in pH within the reaction tank 11 can be detected continuously using a pH meter, or at predetermined times using a pH detection reagent or pH test paper. When the amount of product produced measured by the measuring unit 15 reaches a predetermined value, the aqueous product solution can be discharged from the aqueous solution discharge unit 14. The CO2 removal gas can be discharged from the exhaust unit 12 continuously or at any desired time. Alternatively, the aqueous product solution or the CO2 removal gas may be discharged after a predetermined time has elapsed since the start of the reaction.

[0028] Next, a usage mode of the CO2 recovery system 1 of this embodiment will be described below with reference to the flow chart shown in FIG. 3, it is determined whether or not CO2 gas of 100°C or higher has been discharged from the CO2 discharge equipment 30. If it is determined in step S1 that CO2 gas of 100°C or higher has not been discharged from the CO2 discharge equipment 30, step S1 is performed again.

[0029] 3, if it is determined that CO2 gas at 100°C or higher has been emitted from the CO2 emission equipment 30, the process proceeds to Yes in step S1. Then, in step S2, the aqueous product solution generated previously is charged into the heating tank 22 of the dehydration and drying device 20. Note that, in the first execution, water below 100°C or a predetermined solution can be charged into the heating tank 22 instead of the aqueous product solution.

[0030] 3, CO2 gas at 100°C or higher is supplied from the CO2 discharge facility 30 to the heat exchanger 21 of the dehydration / drying device 20 via the high-temperature gas supply unit 31. After that, in step S4, the product aqueous solution introduced into the heating tank 22 is heated by the heat exchanger 21 to perform dehydration / drying. At the same time, the CO2 gas at 100°C or higher is cooled.

[0031] After step S4 shown in FIG. 3, the following first parallel processing (steps S5 to S51), second parallel processing (steps S6 to S64), and third parallel processing (steps S7 to S71) are performed in parallel.

[0032] 3, it is determined whether or not water has been completely removed from the aqueous product solution in the heating tank 22. The method for this determination is not particularly limited, and for example, it is possible to determine that water has been completely removed when the rate of weight change in the heating tank 22 is monitored and the rate of weight change is equal to or less than a predetermined value. Alternatively, it may be determined that water has been completely removed when a predetermined time has elapsed since the start of dehydration drying in step S4.

[0033] 3, if it is determined that the water has not been completely removed, the process proceeds to No in step S5 and performs step S5 again. On the other hand, if it is determined that the water has been completely removed in step S5, the process proceeds to Yes in step S5. Then, in step S51, the lid 26 of the product recovery unit 24 is opened and the product is recovered in the recovery container 27, and the recovered product is turned into a resource by, for example, individually packaging a predetermined amount so that it can be used as a cleaning agent, and the first parallel process ends.

[0034] 2, an aqueous NaOH solution is introduced into the reaction tank 11 of the CO2 recovery apparatus 10. Then, in step S61, low-temperature CO2 gas is supplied to the CO2 recovery apparatus 10 via the low-temperature gas supply unit 32. After that, in step S62, the low-temperature CO2 gas is bubbled through the aqueous NaOH solution in the reaction tank 11 of the CO2 recovery apparatus 10 to bring the CO2 gas into contact with the aqueous NaOH solution. Then, in step S63, a CO2-removed gas, which is a gas from which CO2 has been removed, is passed through the filter 13 and then exhausted from the exhaust unit 12 as a clean gas.

[0035] 3, it is determined whether the amount of product produced measured by the measuring unit 15 is equal to or greater than a predetermined value. If it is determined in step S64 that the amount of product produced is not equal to or greater than the predetermined value, the process proceeds to No in step S64, and step S61 is performed again. On the other hand, if it is determined in step S64 that the amount of product produced is equal to or greater than the predetermined value, the process proceeds to Yes in step S64. Then, in step S65, the aqueous product solution is discharged from the aqueous solution discharge unit 14, and the second parallel processing is terminated.

[0036] 2, in the third parallel process, the water vapor discharge unit 25 in the dehydrating and drying apparatus 20 is opened to discharge the water vapor generated in the heating tank 22 from the heating tank 22. Then, in step S71, the water vapor discharged from the heating tank 22 is liquefied by the condenser 40 and converted into water, which is then discharged to the outside through the drain 42, thereby completing the third parallel process. This completes the flow. Note that the first to third parallel processes do not necessarily have to be performed in parallel, and the first to third parallel processes may be performed in any order.

[0037] Next, the effects of the CO2 recovery system 1 of this embodiment will be described in detail. In the CO2 capture system 1 of this embodiment, the CO2 capture device 10 produces an aqueous NaHCO3 solution, an aqueous Na2CO3 solution, or an aqueous solution containing NaHCO3 and Na2CO3. The dehydration / drying device 20 produces dehydrated and dried NaHCO3, Na2CO3, or a mixture of NaHCO3 and Na2CO3. The dehydration / drying device 20 then heats the product aqueous solution using heat from CO2 gas at 100°C or higher supplied by the high-temperature gas supply unit 31. The resulting cooled CO2 gas is then supplied to the CO2 capture device 10 by the low-temperature gas supply unit 32 and brought into contact with the NaOH aqueous solution. This configuration eliminates the need for power consumption for both heating the product aqueous solution in the dehydration / drying device 20 and lowering the temperature of the CO2 gas to be contacted with the NaOH aqueous solution. This eliminates the need for CO2 emissions due to the use of fossil fuels for power generation, resulting in a CO2 capture system with excellent CO2 emission reduction effects.

[0038] In this embodiment, CO2 gas at 100°C or higher is contained in the exhaust gas emitted from the CO2 emission equipment 30. This makes it possible to reduce the amount of CO2 emissions in the CO2 emission equipment 30, thereby contributing to the realization of carbon neutrality in factories and other facilities where the CO2 emission equipment 30 is installed.

[0039] In this embodiment, the dehydrating and drying apparatus 20 is provided with an aqueous solution input section 23 for inputting the aqueous product solution into a heating tank 22 equipped with a heat exchanger 21, and a product recovery section 24 for recovering NaHCO3, Na2CO3, or a mixture of NaHCO3 and Na2CO3 in a dehydrated and dried state. This improves the operability of inputting the aqueous product solution into the heating tank 22 of the dehydrating and drying apparatus 20 and recovering the product.

[0040] In this embodiment, the dehydrating and drying device 20 is provided with a condenser 40 that converts water vapor generated by heating the aqueous product solution into water. This prevents water vapor that promotes global warming from being released to the outside, further contributing to the suppression of global warming.

[0041] As described above, according to this embodiment, it is possible to provide a CO2 recovery system 1 that is excellent in the effect of suppressing CO2 emissions.

[0042] In the first embodiment, the heating tank 22 has a hollow rectangular parallelepiped shape as shown in Fig. 2, and the heat exchanger 21 is provided so as to contact the bottom of the heating tank 22. Alternatively, as in modified embodiment 1 shown in Fig. 4(a), the tubular heat exchanger 21 may be provided so as to wrap around the side surface of the hollow rectangular parallelepiped heating tank 22. Alternatively, as in modified embodiment 2 shown in Fig. 4(b), the tubular heat exchanger 21 may be provided so as to contact the bottom surface of the hollow, approximately rectangular parallelepiped heating tank 22 and to meander along the bottom. In Figs. 4(a) and 4(b), the direction perpendicular to both the width direction X and the height direction Z is defined as the front-rear direction Y.

[0043] The shape of the heating tank 22 is not limited to a hollow rectangular parallelepiped, and may be a hollow sphere, as in Modification 3 shown in Figures 5(a) and 5(b). In Modification 3, a tubular heat exchanger 21 is provided so as to wrap around the outer surface of the lower hemispherical portion of the heating tank 22 from bottom to top. Alternatively, as in Modification 4 shown in Figures 6(a) and 6(b), the heating tank 22 may be formed into a hollow sphere, and the heat exchanger 21 may be provided so as to cover substantially the entire outer surface of the lower hemispherical portion of the heating tank 22.

[0044] The heating tank 22 may also be shaped like a polygonal cone, such as a circle or a square, with the apex positioned at the bottom. For example, as in Modification 5 shown in Figures 7(a) and 7(b), the heating tank 22 may be shaped like a hollow cone, with the apex of the cone positioned at the bottom. In Modification 5, the tubular heat exchanger 21 is disposed along the circumferential surface of the heating tank 22, wrapping around it from bottom to top, and the product recovery section 24 is disposed at the apex of the cone.

[0045] 1 , the aqueous solution discharge part 14 and the aqueous solution input part 23 are formed as an integrated unit using a cylindrical member and are directly connected to each other, and the aqueous product solution formed in the reaction tank 11 is directly input to the heating tank 22 via the aqueous solution discharge part 14 and the aqueous solution input part 23. Alternatively, the aqueous solution discharge part 14 and the aqueous solution input part 23 may be formed using separate members and not directly connected to each other, and the aqueous product solution discharged via the aqueous solution discharge part 14 may be temporarily stored in a storage tank, and then the aqueous product solution may be input from the storage tank via the aqueous solution input part 23 into the heating tank 22 at any timing.

[0046] Furthermore, in this embodiment, the water vapor discharged from the water vapor discharge section 25 is liquefied by the condenser 40 and then discharged. However, the water vapor discharged from the water vapor discharge section 25 may be extracted in the state of water vapor without being liquefied and supplied to any facility, etc.

[0047] In the above-described modified embodiments 1 to 5, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The modified embodiments 1 to 5 also achieve the same effects as those in the first embodiment.

[0048] The present invention is not limited to the above-described embodiment and modified forms, and can be applied to various embodiments without departing from the spirit of the present invention. [Explanation of symbols]

[0049] 1: CO2 recovery system, 10: CO2 recovery device, 11: reaction tank, 12: exhaust section, 13: filter, 14: aqueous solution discharge section, 15: measurement section, 20: dehydration and drying device, 21: heat exchanger, 22: heating tank, 23: aqueous solution input section, 24: product recovery section, 25: water vapor discharge section, 28: filter, 31: high-temperature gas supply section, 32: low-temperature gas supply section, 40: condenser

Claims

[Request 1] CO ２ The gas is contacted with an aqueous NaOH solution to form NaHCO ３ Aqueous solution, Na ２ CO ３ Aqueous solution or NaHCO ３ and Na ２ CO ３ CO to produce an aqueous solution containing ２ A recovery device; The above CO ２ The apparatus includes a heater into which the aqueous solution produced by the recovery device is input, and a heat exchanger that heats the aqueous solution input into the heater, and the aqueous solution is heated by the heat exchanger to produce dehydrated and dried NaHCO3. ３ , Na ２ CO ３ , or NaHCO ３ and Na ２ CO ３ a dehydration and drying device for producing a mixture of CO ２ CO above 100°C emitted from the emission equipment ２ a high-temperature gas supply unit that supplies gas to the heat exchanger; CO cooled by the heat exchanger ２ The gas is ２ a low-temperature gas supply unit that supplies the low-temperature gas to the recovery device; and determining whether or not the dehydration and drying of the NaHCO 3 , the Na 2 CO 3 , or the mixture is completed based on a change in weight of the heater after the aqueous solution is introduced into the heater. ２ Collection system. Request 2 The above CO2 at 100°C or higher ２ The gas is the CO ２ The CO according to claim 1, which is contained in exhaust gas discharged from an exhaust facility. ２ Collection system. Request 3 The dehydration and drying device includes an aqueous solution input section for inputting the aqueous solution into the heat exchanger, and an aqueous solution input section for inputting the dehydrated and dried NaHCO ３ , Na ２ CO ３ , or NaHCO ３ and Na ２ CO ３ and a product recovery section for recovering a mixture of ２ Collection system. Request 4 The CO 2 dehydration and drying device according to any one of claims 1 to 3, further comprising a condenser that converts water vapor generated by heating the aqueous solution into water. ２ Collection system.

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