Co2 recovery device and co2 recovery method

Abstract

To provide a CO2 recovery device improved in the degree of freedom in installation.SOLUTION: A CO2 recovery device 1 comprises: a reactor 10 that brings a CO2 - containing gas into contact with a reactive liquid comprising an alkali hydroxide aqueous solution or an alkaline earth hydroxide aqueous solution; and a CO2 - containing gas feed unit 20 that feeds the CO2 - containing gas to the reactor; a water recovery unit 30 that recovers recycled water or water containing at least one of rainwater, domestic waste water, factory waste water, groundwater and river water; a recovered water storage unit 40 that stores recovered water, which is the recycled water or water recovered by the water recovery unit 30; a filtering unit 50 that produces filtered water by filtering the recovered water stored in the recovered water storage unit 40; and a reactive liquid production unit 60 that dissolves a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide by means of the filtered water, thereby producing the reactive liquid L.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a CO2 recovery device and a CO2 recovery method. [Background technology]

[0002] In recent years, there has been a demand to suppress the emission of CO2 gas as a greenhouse gas, and various devices for recovering CO2 have been considered. For example, Patent Document 1 discloses a device for recovering CO2 by producing sodium hydrogen carbonate by gas-liquid contact of a CO2-containing gas with an alkaline aqueous solution containing sodium hydroxide or sodium carbonate that is stored in a storage tank in advance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-206872 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the device disclosed in Patent Document 1, the amount of CO2 fixed is proportional to the concentration and volume of the alkaline aqueous solution, so a large amount of alkaline aqueous solution is required to obtain a sufficient amount of CO2 fixed. Therefore, when installing the device, a large amount of alkaline aqueous solution needs to be transported, which increases the installation cost and reduces the flexibility of installation of the device.

[0005] The present invention has been made in consideration of such problems, and aims to provide a CO2 recovery device and a CO2 recovery method that improve the degree of freedom in installation. [Means for solving the problem]

[0006] One aspect of the present invention is A reaction vessel in which a CO2-containing gas is brought into contact with a reaction liquid comprising an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution; A CO2-containing gas supply unit that supplies a CO2-containing gas to the reaction vessel; A water recovery unit that recovers recycled water or water including at least one of rainwater, domestic wastewater, industrial wastewater, groundwater, and river water; a recovered water storage section for storing the reuse water or the recovered water recovered in the water recovery section; a filtering unit that filters the recovered water stored in the recovered water storage unit to generate filtered water; and a reaction liquid generating unit that generates a reaction liquid consisting of an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution by dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide with the filtrate.

[0007] Another aspect of the present invention is A method for recovering CO2 using the CO2 recovery device, a recovery step of recovering the water or the recycled water by the water recovery unit; a storing step of storing the recovered water in the recovered water storage section; a filtering step of filtering the water stored in the recovered water storage section; a reaction liquid generating step of generating the reaction liquid in the reaction tank by dissolving the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide in the filtrate; and a CO2 fixation reaction step of contacting the CO2-containing gas with the reaction liquid by supplying the CO2-containing gas to the reaction liquid. Effect of the Invention

[0008] In the CO2 recovery device of the above embodiment, the reaction liquid is prepared by dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide in recycled water or water recovered by the water recovery unit. Therefore, when the CO2 recovery device is installed at an installation site, there is no need to prepare a reaction liquid, which reduces installation costs and improves the installation flexibility of the device.

[0009] In the CO2 recovery method according to the other aspect described above, after the CO2 recovery device is installed, the reaction liquid can be generated using the water recovered by the water recovery unit or the recycled water. Therefore, since there is no need to prepare a reaction liquid when installing the O2 recovery device, the installation cost can be reduced and the degree of freedom in installing the device can be improved.

[0010] As described above, according to the above-mentioned aspects, it is possible to provide a CO2 recovery device and a CO2 recovery method that improve the degree of freedom in installation. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a CO2 capture system in a first embodiment. [Diagram 2] FIG. 2 is a flow diagram showing a usage mode of the CO2 capture system in the first embodiment. [Diagram 3] FIG. 11 is a conceptual diagram showing the configuration of a CO2 capture system in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Embodiment 1) A first embodiment of the CO2 recovery device will be described with reference to Figures 1 and 2. As shown in Figure 1, the CO2 recovery device 1 mainly includes a reaction tank 10, a CO2-containing gas supply unit 20, a water recovery unit 30, a recovered water storage unit 40, a filtration unit 50, and a reaction liquid production unit 60. Each component will be described in detail below.

[0013] 1. Reaction tank 10 and CO2-containing gas supply unit 20 The reaction tank 10 is configured to store a reaction liquid L for recovering CO2 from a CO2-containing gas by contacting the gas. The reaction liquid L can be an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution, and in the present embodiment 1, an aqueous NaOH solution is used. The concentration of the aqueous NaOH solution is not limited, but in the present embodiment 1, a 5.0% aqueous NaOH solution is used, which is easy to handle because it is not a deleterious substance. The reaction tank 10 may be provided with a stirring device (not shown) for stirring the reaction liquid L stored in the reaction tank 10. The stirring device can be driven by power supplied by a power supply unit 80 described later.

[0014] A CO2-containing gas is supplied to the reaction vessel 10 by the CO2-containing gas supply unit 20. The term "CO2-containing gas" refers to a gas containing CO2 as a constituent component. The CO2-containing gas may be a gas containing only CO2 as a constituent component, or may further contain unavoidable impurities. The CO2-containing gas may 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. For example, the CO2-containing gas may be the atmosphere, exhaust gas from a factory, etc., and in this embodiment, the atmosphere is used.

[0015] The gas discharge part 21 of the CO2-containing gas supply part 20 is located near the inner bottom of the reaction vessel 10 and is configured to discharge air into the reaction liquid L to create bubbles. In order to increase the frequency of contact between the air and the reaction liquid L, it is preferable to discharge the air in the form of microbubbles for bubbling. The microbubbles can be formed by a microbubble generator (not shown) provided at the tip of the gas discharge part 21.

[0016] Then, in the reaction tank 10, the air as a CO2-containing gas is brought into contact with an aqueous NaOH solution as the reaction liquid L, whereby the reaction of the following formula 1 is carried out, and then the reaction of the following formula 2 is carried out. In this specification, the following formulas 1 and 2 are also referred to as CO2 fixation reactions. 2NaOH+CO2→ Na2CO3+H2O (Formula 1) Na2CO3+CO2+H2O → 2NaHCO3 (formula 2)

[0017] In the reaction vessel 10, before the start of the reaction, there is no NaHCO3 and no Na2CO3. Depending on the progress of the reaction, the reaction may proceed in one of the following states: Na2CO3 is generated and no NaHCO3 is present; some Na2CO3 further reacts with CO2 to generate NaHCO3 and both are present; or all Na2CO3 is converted to NaHCO3 and no Na2CO3 is present and NaHCO3 is present. Both NaHCO3 and Na2CO3 generated by the reaction are dissolved in the water in the reaction vessel 10 and are in the form of an aqueous solution. In this specification, NaHCO3, Na2CO3, and a mixture of both are collectively referred to as "product", and these aqueous solutions are collectively referred to as "aqueous product solution". Although not shown, the reaction vessel 10 may be provided with a temperature sensor for detecting the temperature of the reaction liquid L, a sensor capable of detecting a pH change in the reaction liquid L, and a weighing scale capable of measuring the weight of the reaction vessel 10 (including the reaction liquid L and the product).

[0018] In this embodiment, the CO2-containing gas supply unit 20 can be configured to supply pressurized air by an air pump that takes in air to the reaction tank 10. Since the air pump can supply pressurized air to the reaction tank 10, CO2 can be efficiently taken in even from air with a low CO2 concentration.

[0019] The air pump is driven by a power supply unit 80. The power supply unit 80 can be configured by a power conversion system (not shown) capable of converting renewable energy such as solar energy into electric power. It is preferable to adopt an air pump that consumes little power. This makes it easy to drive the air pump based on the electric power generated by the power conversion system, and CO2 is not emitted for the drive, or the amount of CO2 emitted can be reduced. This contributes to reducing the amount of CO2 emitted by the entire device. If the voltage of the electric power generated by the power conversion system is insufficient when driving the air pump, a booster device may be provided in front of the air pump. Also, a power storage device that accumulates the electric power generated by the power conversion system may be provided, and power may be supplied from the power storage device when there is a power shortage.

[0020] 2. Water recovery section 30 and recovered water storage section 40 The water recovery unit 30 recovers recycled water or water. The recycled water includes at least one of rainwater, domestic wastewater, industrial wastewater, groundwater, and river water. The water includes pure water, tap water, and the like. In this embodiment, the water recovery unit 30 is configured to recover rainwater as recycled water. For example, it is configured to be installed on the rooftop of a building to capture rainwater. In addition, when recovering tap water, the water recovery unit 30 can be configured to be connected to a faucet that supplies tap water.

[0021] The water etc. recovered by the water recovery section 30 (hereinafter also referred to as "recovered water" in this specification) is stored in the recovered water storage section 40. The recovered water storage section 40 can be configured as a tank having a desired capacity. In this embodiment, the recovered water storage section 40 is located lower in the gravitational direction than the water recovery section 30, so that the water recovered in the water recovery section 30 or reused water can be made to flow down toward the recovered water storage section 40 by gravity.

[0022] 3.Filtration section 50 The filtration unit 50 generates filtered water by filtering the recovered water stored in the recovered water storage unit 40. The configuration of the filtration unit 50 is not limited, and a known configuration can be adopted. In this embodiment, the filtration unit 50 is configured by a predetermined filter. The filtration unit 50 may be configured by a plurality of filtration devices having different configurations. In this embodiment, the filtration unit 50 is located lower in the gravitational direction than the recovered water storage unit 40, so that the water or reused water stored in the recovered water storage unit 40 can be caused to flow down toward the filtration unit 50 by gravity.

[0023] In this embodiment, the filtration unit 50 is provided with a dissolution tank flow path 51 communicating with a dissolution tank 61 described below, and a first reaction tank flow path 52 which is a flow path communicating with the reaction tank 10. The filtered water filtered by the filtration unit 50 is supplied to the dissolution tank 61 via the dissolution tank flow path 51, and is supplied to the reaction tank 10 via the first reaction tank flow path 52.

[0024] 4. Reaction solution generating unit 60 The reaction liquid generation section 60 generates the reaction liquid L by dissolving the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide in the filtrate filtered by the filtration section 50. In this embodiment, the reaction liquid generation section 60 includes a dissolution tank 61 and a dilution section 62.

[0025] 4-1.Dissolution tank 61 The dissolution tank 61 dissolves a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide (hereinafter, in this embodiment, also referred to as a "solid solute"). The dissolution tank 61 is provided with a "solid solute" and is configured to receive filtered water via the dissolution tank flow path 51. In this embodiment, the dissolution tank 61 is located lower than the filtration section 50 in the gravitational direction. This allows the filtered water to be supplied to the dissolution tank 61 by utilizing gravity.

[0026] The solid solute can be supplied to the dissolution tank 61 by the user. For example, the solid solute may be enclosed in a cartridge that is detachable from the dissolution tank 61, and the user may replace the cartridge as necessary to supply the solid alkali metal hydroxide or solid alkaline earth metal hydroxide to the dissolution tank 61 at a desired timing. This prevents the user from directly touching the solid solute when manually supplying it to the dissolution tank 61, improving workability. The dissolution tank 61 may be provided with a known stirring device to promote dissolution of the solid solute. The stirring device may be one that is driven by power supplied by the power supply unit 80.

[0027] The filtrate supplied to the dissolution tank 61 can be adjusted by the first filtrate adjustment unit 611 provided in the dissolution tank flow path 51. When a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide is dissolved in water, heat is generated. The amount of heat generated depends on the concentration of the solute (alkali metal hydroxide or alkaline earth metal hydroxide) in the aqueous solution after dissolution and the volume of the aqueous solution. Therefore, for the same volume of aqueous solution, more heat is generated when a low-concentration aqueous solution is obtained than when a high-concentration aqueous solution is obtained by dissolving a solid solute in water. Therefore, in this embodiment, first, in the dissolution tank 61, a solid solute is dissolved to prepare a high-concentration aqueous solution of an alkali metal hydroxide or an alkaline earth metal hydroxide. Then, the high-concentration aqueous solution is used as a reaction stock solution, and the reaction stock solution is diluted as described below to produce the reaction liquid L.

[0028] The concentration of the solute (alkali metal hydroxide or alkaline earth metal hydroxide) in the aqueous solution of the reaction stock solution is not particularly limited, and may be set to a level where the heat generated by dissolving the solid solute falls within an allowable range. The allowable range of the heat generated by dissolving the solid solute in the dissolution tank 61 may be set so that the amount of heat generated per unit time is equal to or less than a predetermined reference value. As the allowable range, for example, when the solute is NaOH, the NaOH concentration of the reaction stock solution may be set to 48% or less. The allowable range may also be set based on the flow rate per unit time of the filtered water supplied to the dissolution tank 61 by the first filtrate water adjustment unit 611. For example, the amount of heat generated per unit time can be reduced by reducing the flow rate per unit time of the filtered water supplied to the dissolution tank 61 by the first filtrate water adjustment unit 611.

[0029] The first filtered water adjustment unit 611 may be configured with a valve. The operating state of the first filtered water adjustment unit 611, for example, the open / close state of the valve, may be manually operated by a user or may be controlled by a control unit (not shown). The first filtered water adjustment unit 611 may be operated by power supplied by the power supply unit 80.

[0030] In this embodiment, the dissolution tank 61 is provided with a second reaction tank flow path 612, which is a flow path communicating with the reaction tank 10, as described below. The second reaction tank flow path 612 supplies the reaction stock solution generated in the dissolution tank 61 to the reaction tank 10.

[0031] 4-2.Dilution section 62 The dilution unit 62 dilutes the reaction stock solution produced in the dissolution tank 61. In this embodiment, the dilution unit 62 is composed of the reaction tank 10, a first reaction tank flow path 52, and a second reaction tank flow path 612. The dilution unit 62 supplies filtrate water to the reaction tank 10 through the first reaction tank flow path 52, and then supplies the reaction stock solution to the reaction tank 10 through the second reaction tank flow path 612, thereby diluting the reaction stock solution with the filtrate water in the reaction tank 10. As a result, a reaction solution L is produced in the reaction tank 10.

[0032] The flow rate and flow velocity of the reaction stock solution supplied to the reaction vessel 10, and the start and stop of supply of the reaction stock solution are adjusted by a stock solution adjustment unit 621 provided in the second reaction vessel flow path 612. The stock solution adjustment unit 621 can be configured with a valve. The operation state of the stock solution adjustment unit 621 (in this embodiment, the open / close state of the valve) may be manually operated by a user, or may be controlled by a control unit (not shown). The stock solution adjustment unit 621 may be driven by power supplied by a power supply unit 80. Since the reaction vessel 10 is located lower than the dissolution vessel 61 in the gravitational direction, the reaction stock solution generated in the dissolution vessel 61 can flow through the second reaction vessel flow path 612 toward the reaction vessel 10 by gravity.

[0033] The stock solution adjusting unit 621 can also supply the stock solution to the reaction tank 10 on condition that a predetermined volume or more of filtered water is stored in the reaction tank 10. For example, a water level gauge, a liquid detector, a weight scale, or the like provided in the reaction tank 10 can be used to acquire information that a predetermined volume of filtered water is stored in the reaction tank 10, and in this case, the stock solution adjusting unit 621 can be configured to be able to supply the stock solution to the reaction tank 10.

[0034] The flow rate and flow speed of the filtrate supplied to the reaction tank 10, and the start and stop of the supply of the filtrate are adjusted by a second filtrate adjustment unit 622 provided in the first reaction tank flow path 52. The second filtrate adjustment unit 622 can be configured with a valve. The operating state of the second filtrate adjustment unit 622 (in this embodiment, the open / close state of the valve) may be manually operated by a user or may be controlled by a control unit (not shown). The second filtrate adjustment unit 622 may be driven by power supplied by a power supply unit 80. Since the reaction tank 10 is located lower than the filtration unit 50 in the gravitational direction, the filtrate generated in the filtration unit 50 can flow through the first reaction tank flow path 52 toward the reaction tank 10 by gravity.

[0035] The supply of filtrate to the reaction tank 10 by the second filtrate adjustment unit 622 may be given priority over the supply of filtrate to the dissolution tank 61 by the above-mentioned first filtrate adjustment unit 611. This allows the supply of the reaction stock solution to the reaction tank 10 in a state where a sufficient amount of filtrate is stored in the reaction tank 10.

[0036] When the operating states of the raw solution adjustment unit 621 and the second filtrate adjustment unit 622 are controlled by the control unit, the operating states of the raw solution adjustment unit 621 and the second filtrate adjustment unit 622 can be controlled based on the detection results of a water level gauge, a liquid detector, a pH sensor, a weight meter, etc. provided in the reaction tank 10. For example, when it is determined that the NaOH concentration in the reaction tank 10 has become equal to or lower than a predetermined value based on the detection results of a pH sensor, a weight meter, etc. provided in the reaction tank 10, the valve constituting the raw solution adjustment unit 621 can be opened to supply a predetermined amount of reaction raw solution to the reaction tank 10, or when it is determined that the amount of liquid in the reaction tank 10 has decreased based on the detection results of a water level gauge, a liquid detector, or a weight meter provided in the reaction tank 10, the valve constituting the second filtrate adjustment unit 622 can be opened to supply a predetermined amount of filtrate to the reaction tank 10.

[0037] In this way, the control unit (not shown) can control the stock solution adjustment unit 621 and the second filtrate water adjustment unit 622 to operate in cooperation with each other so that the final concentration of the reaction solution L in the reaction tank 10 becomes a predetermined value. Note that, although heat is also generated when the reaction stock solution is diluted with the filtrate water stored in the reaction tank 10, the amount of filtrate water stored in the reaction tank 10 is sufficiently large compared to the reaction stock solution, and therefore the heat capacity of the filtrate water in the reaction tank 10 is large, and the temperature rise of the reaction solution L due to the heat generated by dilution falls within an allowable range.

[0038] 5. Exhaust section 70 As shown in Fig. 1, in the CO2 recovery device 1, the reaction tank 10 is provided with an exhaust unit 70. The exhaust unit 70 exhausts the CO2-removed gas from which CO2 has been removed in the reaction tank 10 to the reaction tank 10. An impurity removal filter (not shown) is connected to the exhaust unit 70, and the CO2-removed gas exhausted from the exhaust unit 70 is released to the outside with impurities including harmful substances removed by the impurity removal filter.

[0039] 6. Product recovery section 71 The product recovery section 71 is provided in the reaction tank 10, and the aqueous product solution produced in the reaction tank 10 can be taken out from the reaction tank 10 via the product recovery section 71. The product recovery section 71 can be configured, for example, by a drain cock. The aqueous product solution recovered by the product recovery section 71 can be used as a resource, and can be used, for example, as a cleaning agent, an antiseptic, a deodorant, etc.

[0040] 7. CO2 capture method using CO2 capture device 1 A CO2 capture method using the CO2 capture device 1 of this embodiment will be described in detail below with reference to the flow diagram of Fig. 2. First, in step S1 of Fig. 2, a recovery process is performed in which reuse water or water is recovered by the water recovery unit 30. In this embodiment, rainwater is recovered as reuse water. Then, in step S2, a storage process is performed in which the recovered water recovered by the recovered water storage unit 40 is stored in the recovered water storage unit 40. Note that thereafter, the capture process S1 and the storage process S2 are performed continuously.

[0041] 2, a filtering step is performed in which the recovered water stored in the recovered water storage unit 40 is supplied to the filtering unit 50 and the recovered water is filtered by the filtering unit 50. Thereafter, steps S4 and S5 are performed in parallel.

[0042] First, in step S4, a reaction tank storage step is performed in which the filtrate filtered by the filtration unit 50 is supplied to the reaction tank 10 through the second reaction tank flow path 612, thereby storing the filtrate in the reaction tank 10. The flow rate and flow velocity of the filtrate to the reaction tank 10 are adjusted to predetermined values ​​by the second filtrate adjustment unit 622.

[0043] Meanwhile, in step S5, a reaction stock solution generating step is performed in which the filtrate filtered by the filtration unit 50 is supplied to the dissolution tank 61 through the dissolution tank flow path 51 to dissolve a solid solute (solid NaOH in this embodiment) previously provided in the dissolution tank 61, thereby generating a reaction stock solution. The flow rate and flow velocity of the filtrate to the dissolution tank 61 are adjusted to predetermined values ​​by the first filtrate adjustment unit 611.

[0044] Then, after steps S4 and S5 are performed in parallel, in step S6, the reaction stock solution is supplied from the dissolution tank 61 to the reaction tank 10 through the second reaction tank flow path 612 to generate a reaction liquid L. The flow rate and flow velocity of the reaction stock solution supplied from the dissolution tank 61 to the reaction tank 10 are adjusted to predetermined values ​​by the stock solution adjustment unit 621.

[0045] Thereafter, in step S7, a CO2 fixation reaction process is performed in which the reaction liquid L is contacted with the CO2-containing gas by supplying the CO2-containing gas from the CO2-containing gas supply unit 20 to the reaction liquid L. The flow rate and flow velocity of the air as the CO2-containing gas supplied to the reaction liquid L are adjusted to a predetermined value by the air pump constituting the CO2-containing gas supply unit 20.

[0046] In step S8, if the NaOH concentration in the reaction liquid L becomes equal to or lower than a predetermined value, it is determined to be a CO2 fixation reaction process. Then, in step S9, the product aqueous solution is recovered from the reaction tank 10 through the product recovery section 71.

[0047] Then, step S3 and subsequent steps are performed again. In step S4, if the amount of liquid in the reaction tank 10 is equal to or greater than a predetermined amount, the process can proceed to the next step S6 without supplying filtered water. In this embodiment, the CO2 capture method using the CO2 capture device 1 can be performed as described above.

[0048] 8. Confirmatory Test A confirmation test was conducted on the CO2 fixation in the CO2 capture device 1 of the present embodiment 1. In the confirmation test, the initial concentration of the reaction liquid L was adjusted to 5% NaOH, and the air was supplied to the reaction tank 10 at 1 L / min by the CO2-containing gas supply unit 20. Then, the amount of CO2 captured was measured for about 100 days. As a result, the amount of CO2 captured by the CO2 capture device 1 was a value roughly equivalent to the amount of CO2 contained in the total air supplied to the reaction tank 10 when converted assuming that the CO2 concentration in the air is 520 ppm. Therefore, the confirmation test confirmed that the CO2 capture device 1 has sufficient CO2 capture performance.

[0049] 9. Effects of the CO2 recovery device 1 of the first embodiment According to the CO2 recovery apparatus 1 of the first embodiment, the reaction liquid L is prepared by dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide with recycled water or water recovered by the water recovery unit 30. Therefore, when the CO2 recovery apparatus 1 is installed at an installation site, it is not necessary to prepare the reaction liquid L, so that the installation cost can be reduced and the degree of freedom in installing the CO2 recovery apparatus 1 can be improved.

[0050] In the first embodiment, the reaction liquid generating section 60 includes a dissolving tank 61 for dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide with filtered water to generate a reaction stock solution consisting of an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution having a higher concentration than the reaction liquid L, and a diluting section 62 for diluting the reaction stock solution with filtered water to generate the reaction liquid L. This makes it possible to easily generate the reaction liquid L. Furthermore, by generating a high-concentration reaction stock solution and then generating the reaction liquid L, it becomes easy to keep the heat generated when generating the reaction liquid L within an allowable range.

[0051] In the first embodiment, the dilution unit 62 is configured to supply filtrate water and the reaction stock solution to the reaction tank 10, thereby diluting the reaction stock solution with the filtrate water in the reaction tank 10 to generate the reaction solution L. As a result, since a large amount of filtrate water is present in the reaction tank 10 relative to the reaction stock solution, it becomes easy to keep the temperature rise of the reaction solution L caused by the heat generated by diluting the reaction stock solution within an allowable range.

[0052] In the first embodiment, the filtration section 50 is provided with a dissolution tank flow path 51 communicating with the dissolution tank 61 and a second reaction tank flow path 612 communicating with the reaction tank 10, and the dissolution tank 61 is provided with a second reaction tank flow path 612 communicating with the reaction tank 10. The dilution section 62 is configured to store the filtrate in the reaction tank 10 by supplying filtrate from the filtration section 50 to the reaction tank 10 through the first reaction tank flow path 52, prepare a reaction stock solution from the filtrate supplied from the filtration section 50 through the dissolution tank flow path 51, and supply the reaction stock solution from the dissolution tank 61 to the reaction tank 10 through the second reaction tank flow path 612, thereby diluting the reaction stock solution to generate the reaction liquid L. As a result, the filtrate used to dissolve the solid solute and the filtrate used to dilute the reaction stock solution can be supplied to the reaction tank 10 through different routes, making it easy to dilute the reaction stock solution with the filtrate present in the reaction tank 10 in large quantities. As a result, it is easy to keep the heat generated during dilution within an allowable range, and the dilution section 62 is easy to use.

[0053] Moreover, in the first embodiment, the dilution section 62 includes a stock solution adjustment section 621 that adjusts the flow rate or flow speed of the reaction stock solution supplied to the reaction tank 10 to adjust the concentration of the alkali metal hydroxide or alkaline earth metal hydroxide in the reaction solution L. This makes it easy to adjust the concentration of the alkali metal hydroxide or alkaline earth metal hydroxide in the reaction solution L to a desired value.

[0054] Moreover, in the first embodiment, the dilution unit 62 includes a second filtrate adjustment unit 622 that adjusts the flow rate or flow speed of the filtrate supplied to the reaction tank 10 to adjust the concentration of the alkali metal hydroxide or alkaline earth metal hydroxide in the reaction liquid L. This makes it easy to adjust the concentration of the alkali metal hydroxide or alkaline earth metal hydroxide in the reaction liquid L to a desired value.

[0055] In addition, in the present embodiment 1, the CO2-containing gas is the atmosphere. This makes it possible to fix CO2 in the atmosphere, which contributes to reducing greenhouse gases.

[0056] In addition, in this embodiment 1, a CO2 recovery method using the CO2 recovery device 1 includes a recovery step S1 of recovering reuse water or water by the water recovery section 30, a storage step S2 of storing the recovered recovered water in the recovered water storage section 40, a filtration step S3 of filtering the stored water stored in the recovered water storage section 40, a reaction liquid generation step S6 of generating a reaction liquid L in the reaction tank 10 by dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide with the filtered water, and a CO2 fixation reaction step S7 of contacting the reaction liquid L with a CO2-containing gas by supplying the CO2-containing gas to the reaction liquid L. According to this CO2 recovery method, CO2 can be fixed using the CO2 recovery device 1 of this embodiment 1.

[0057] In this embodiment 1, the CO2 recovery method using the CO2 recovery device 1 includes a recovery step S1 of recovering recycled water or water by the water recovery section 30, a storage step S2 of storing the recovered recovered water in the recovered water storage section 40, a filtration step S3 of filtering the stored water stored in the recovered water storage section 40, a reaction tank storage step S4 of storing the filtered water in the reaction tank 10 by supplying the filtered water to the reaction tank 10, a reaction stock solution generation step S5 of dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide by supplying the filtered water to the dissolution tank 61 to generate a reaction stock solution, a reaction liquid generation step S6 of diluting the reaction stock solution by supplying the reaction stock solution to the reaction tank 10 in which the filtrate is stored to generate a reaction liquid L, and a CO2 fixation reaction step S7 of contacting the reaction liquid L with a CO2-containing gas by supplying a CO2-containing gas to the reaction liquid L. According to this CO2 recovery method, CO2 can be fixed using the CO2 recovery device 1 of this embodiment 1.

[0058] In this embodiment 1, the CO2 recovery method using the CO2 recovery device 1 includes a recovery step S1 of recovering recycled water or water by the water recovery section 30, a storage step S2 of storing the recovered recovered water in the recovered water storage section 40, a filtration step S3 of filtering the stored water stored in the recovered water storage section 40, a reaction tank storage step S4 of storing the filtered water in the reaction tank 10 by supplying the filtered water from the filtration section 50 to the reaction tank 10 through the first reaction tank flow path 52, a reaction stock solution generation step S5 of supplying the filtered water from the filtration section 50 to the dissolution tank 61 through the dissolution tank flow path 51 to dissolve a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide to generate a reaction stock solution, a reaction liquid generation step S6 of diluting the reaction stock solution by supplying the reaction stock solution from the dissolution tank 61 to the reaction tank 10 through the second reaction tank flow path 612, and generating a reaction liquid L, and a CO2 fixation reaction step S7 of contacting the reaction liquid L with a CO2-containing gas by supplying a CO2-containing gas to the reaction liquid L. According to the CO2 capture method, the CO2 capture device 1 of the first embodiment can be used to fix CO2.

[0059] As described above, according to this embodiment, it is possible to provide a CO2 recovery device 1 and a CO2 recovery method that improve the degree of freedom in installation.

[0060] (Embodiment 2) In the above-mentioned embodiment 1, the filtration section 50 is provided with the dissolution tank passage 51 and the first reaction tank passage 52, but instead, in the CO2 recovery device 1 of the embodiment 2, as shown in Fig. 3, the filtration section 50 is provided with the dissolution tank passage 51, but the first reaction tank passage 52 is not provided, and the second filtrate water adjustment section 622 is not provided. The other configurations are the same as those in the embodiment 1, and the same reference numerals as those in the embodiment 1 are used, and the description thereof will be omitted.

[0061] In the CO2 recovery device 1 of the second embodiment, the filtration section 50 is provided with a dissolution tank flow path 51 communicating with the dissolution tank 61, and the dissolution tank 61 is provided with a reaction tank flow path 613 communicating with the reaction tank 10. The dilution section 62 is configured to store the filtrate in the reaction tank 10 by supplying filtrate from the filtration section 50 to the reaction tank 10 through the dissolution tank flow path 51, the dissolution tank 61, and the reaction tank flow path 613, create a reaction stock solution from the filtrate supplied from the filtration section 50 to the dissolution tank 61 through the dissolution tank flow path 51, and supply the reaction stock solution from the dissolution tank 61 to the reaction tank 10 through the reaction tank flow path 613, thereby diluting the reaction stock solution with the filtrate stored in the reaction tank 10 to generate the reaction liquid L. According to this, without providing the first reaction tank flow path 52 in the first embodiment, the filtrate can be stored in the reaction tank 10 and the reaction stock solution can be diluted with the filtrate to generate the reaction liquid L. As a result, the same effects as those in the first embodiment can be achieved. The flow rate and flow path of the filtrate supplied to the reaction tank 10, and the start and stop of the supply of the filtrate can be controlled by a first filtrate adjustment unit 611.

[0062] In the CO2 capture method using the CO2 capture device 1 of the second embodiment, as shown in FIG. 2, the capture step S1, the storage step S2, and the filtration step S3 are performed in the same manner as in the first embodiment. In the reaction tank storage step S4, the filtrate is supplied from the filtration section 50 to the reaction tank 10 through the dissolution tank flow path 51, the dissolution tank 61, and the reaction tank flow path 613 to store the filtrate in the reaction tank 10, and in the reaction stock solution generation step S5, the filtrate is supplied from the filtration section 50 to the dissolution tank 61 through the dissolution tank flow path 51 to dissolve the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide to generate a reaction stock solution. In the reaction solution generation step S6, the reaction stock solution is supplied from the dissolution tank 61 to the reaction tank 10 through the reaction tank flow path 613 to dilute the reaction stock solution to generate a reaction solution L. Thereafter, the CO2 fixation reaction step S7 is performed in the same manner as in the first embodiment. As a result, CO2 can be fixed using the CO2 capture device 1 of the second embodiment.

[0063] The present invention is not limited to the above-mentioned first and second embodiments, and can be applied to various embodiments without departing from the gist of the present invention. [Explanation of symbols]

[0064] 1: CO2 recovery device, 10: reaction tank, 20: CO2-containing gas supply unit, 30: water recovery unit, 40: recovered water storage unit, 50: filtration unit, 51: dissolution tank flow path, 52: first reaction tank flow path, 60: reaction liquid production unit, 61: dissolution tank, 611: first filtrate adjustment unit, 612: second reaction tank flow path, 613: reaction tank flow path, 62: dilution unit, 621: raw solution adjustment unit, 622: second filtrate adjustment unit, 70: exhaust unit, 71: product recovery unit

Claims

1. A reaction solution consisting of an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution is added with CO ２ a reaction vessel for contacting the containing gas; CO ２ CO containing gas is supplied to the reaction vessel ２ a containing gas supply unit; a water recovery unit that recovers recycled water or water including at least one of rainwater, domestic wastewater, industrial wastewater, groundwater, and river water; a recovered water storage section that stores the recycled water or the water recovered by the water recovery section; a filtering unit that generates filtered water by filtering the recovered water stored in the recovered water storage unit; a reaction solution generating unit that generates the reaction solution by dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide in the filtered water, ２ Recovery device.

2. The reaction solution generating unit comprises: a dissolution tank for dissolving a solid alkali metal hydroxide or a solid alkaline earth metal hydroxide in the filtered water to prepare a reaction stock solution comprising an aqueous alkali metal hydroxide solution or an aqueous alkaline earth metal hydroxide solution having a higher concentration than the reaction solution; and a dilution unit for diluting the reaction stock solution with the filtered water to produce the reaction solution. ２ Recovery device.

3. 3. The CO 2 according to claim 2, wherein the dilution unit is configured to supply the filtrate and the reaction stock solution to the reaction tank, thereby diluting the reaction stock solution with the filtrate in the reaction tank to generate the reaction solution. ２ Recovery device.

4. the filtration unit is provided with a dissolution tank flow path communicating with the dissolution tank and a first reaction tank flow path communicating with the reaction tank, the dissolution tank is provided with a second reaction tank flow path communicating with the reaction tank, The dilution section The filtrate is supplied from the filtration section to the reaction tank through the first reaction tank flow path, thereby storing the filtrate in the reaction tank; The CO2 reactor according to claim 3, wherein the reaction stock solution is prepared using the filtered water supplied from the filtration unit through the dissolution tank flow path, and the reaction stock solution is supplied from the dissolution tank through the second reaction tank flow path to the reaction tank, thereby diluting the reaction stock solution and producing the reaction solution. ２ Recovery device.

5. the filtration unit is provided with a dissolution tank flow path communicating with the dissolution tank, the dissolution tank is provided with a reaction tank flow path communicating with the reaction tank, The dilution section The filtrate is supplied from the filtration unit through the dissolution tank flow path, the dissolution tank, and the reaction tank flow path to the reaction tank, thereby storing the filtrate in the reaction tank; The CO2 analyzer according to claim 3, wherein the reaction stock solution is prepared from the filtered water supplied from the filtration unit to the dissolution tank through the dissolution tank flow path, and the reaction stock solution is supplied from the dissolution tank to the reaction tank through the reaction tank flow path, thereby diluting the reaction stock solution with the filtered water stored in the reaction tank to produce the reaction solution. ２ Recovery device.

6. The CO 2 solution according to any one of claims 2 to 5, wherein the dilution unit includes a stock solution adjusting unit that adjusts the flow rate or flow velocity of the reaction stock solution supplied to the reaction tank to adjust the concentration of alkali metal hydroxide or alkaline earth metal hydroxide in the reaction solution. ２ Recovery device.

7. The dilution unit includes a filtrate adjusting unit that adjusts the flow rate or flow velocity of the filtrate supplied to the reaction tank to adjust the concentration of alkali metal hydroxide or alkaline earth metal hydroxide in the reaction solution. ２ Recovery device.

8. The CO ２ The CO2 gas according to any one of claims 1 to 5, wherein the containing gas is atmospheric air. ２ Recovery device.

9. The CO according to any one of claims 1 to 5 ２ CO using a recovery device ２ A recovery method comprising: a recovery step of recovering the reused water or the water by the water recovery unit; a storing step of storing the recovered water in the recovered water storage section; a filtering step of filtering the water stored in the recovered water storage section; a reaction solution generating step of generating the reaction solution in the reaction tank by dissolving the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide in the filtered water; The reaction solution is added with CO ２ The CO 2 -containing gas is supplied to the reaction solution. ２ CO containing gas contact ２ and a fixation reaction step. ２ Recovery method.

10. CO according to claim 2 or 3 ２ CO using a recovery device ２ A recovery method comprising: a recovery step of recovering the reused water or the water by the water recovery unit; a storing step of storing the recovered water in the recovered water storage section; a filtering step of filtering the water stored in the recovered water storage section; a reaction tank storage step of storing the filtrate in the reaction tank by supplying the filtrate to the reaction tank; a reaction stock solution producing step of producing the reaction stock solution by supplying the filtered water to the dissolution tank to dissolve the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide; a reaction solution producing step of diluting the reaction stock solution by supplying the reaction stock solution to the reaction tank in which the filtrate is stored to produce the reaction solution; The reaction solution is added with CO ２ The CO 2 -containing gas is supplied to the reaction solution. ２ CO containing gas contact ２ and a fixation reaction step. ２ Recovery method.

11. The CO according to claim 4 ２ CO using a recovery device ２ A recovery method comprising: a recovery step of recovering the reused water or the water by the water recovery unit; a storing step of storing the recovered water in the recovered water storage section; a filtering step of filtering the water stored in the recovered water storage section; a reaction tank storing step of storing the filtrate in the reaction tank by supplying the filtrate from the filtration section to the reaction tank through the first reaction tank flow path; a reaction stock solution generating step of supplying the filtered water from the filtration section to the dissolution tank through the dissolution tank flow path to dissolve the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide, thereby generating the reaction stock solution; a reaction solution generating step of supplying the reaction stock solution from the dissolution tank through the second reaction tank flow path to the reaction tank, thereby diluting the reaction stock solution and generating the reaction solution; The reaction solution is added with CO ２ The CO 2 -containing gas is supplied to the reaction solution. ２ CO containing gas contact ２ and a fixation reaction step. ２ Recovery method.

12. The CO according to claim 5 ２ CO using a recovery device ２ A recovery method comprising: a recovery step of recovering the reused water or the water by the water recovery unit; a storing step of storing the recovered water in the recovered water storage section; a filtering step of filtering the water stored in the recovered water storage section; a reaction tank storing step of storing the filtrate in the reaction tank by supplying the filtrate from the filtration unit through the dissolution tank flow path, the dissolution tank, and the reaction tank flow path to the reaction tank; a reaction stock solution generating step of supplying the filtered water from the filtration section to the dissolution tank through the dissolution tank flow path to dissolve the solid alkali metal hydroxide or the solid alkaline earth metal hydroxide, thereby generating the reaction stock solution; a reaction solution generating step of supplying the reaction stock solution from the dissolution tank through the reaction tank flow path to the reaction tank, thereby diluting the reaction stock solution to generate the reaction solution; The reaction solution is added with CO ２ The CO 2 -containing gas is supplied to the reaction solution. ２ CO containing gas contact ２ and a fixation reaction step. ２ Recovery method.

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