Gas recovery device and gas recovery method

Abstract

In order to reduce energy cost, provided is a gas recovery device for separating carbon dioxide from a carbon dioxide-containing supply gas and recovering the carbon dioxide, the device comprising: a carbon dioxide separation unit having a carbon dioxide separator and configured to separate the carbon dioxide from the supply gas; a vapor supply unit configured to generate vapor in order to reduce the partial pressure of the carbon dioxide in the carbon dioxide separation unit by supplying the vapor to the carbon dioxide separation unit and; and a control unit configured to control the state or amount of the vapor supplied from the vapor supply unit.

Description

Gas recovery device and gas recovery method

[0001] The present disclosure relates to a gas recovery device and a gas recovery method for recovering carbon dioxide contained in exhaust gas or the atmosphere.

[0002] In recent years, carbon dioxide emissions from the combustion of fossil fuels at power plants, steel mills, and other facilities have led to an increase in atmospheric carbon dioxide concentrations, raising concerns about global environmental change. Therefore, there is a global urgent need to achieve a carbon-neutral society by reducing carbon dioxide emissions or capturing emitted carbon dioxide. To achieve a carbon-neutral society, it is necessary to implement a carbon circulation system that can capture carbon dioxide from exhaust gases, the atmosphere, and other sources at low cost and reuse it as a resource.

[0003] Furthermore, with the recent advances in space and deep-sea development, it is expected that more and more people will live in enclosed spaces such as space stations and submarines. As people consume oxygen and emit carbon dioxide through breathing, the carbon dioxide concentration in the space increases. In order to live sustainably in such enclosed spaces, it is necessary to capture and reuse carbon dioxide.

[0004] Chemical absorption has been known as a carbon dioxide separation technique. In this chemical absorption method, carbon dioxide is adsorbed from a mixed gas by a low-temperature amine absorption liquid, and the adsorbed carbon dioxide is desorbed by heating to 120°C or higher. For example, Patent Document 1 discloses an amine-containing concentration system that can concentrate useful amines that react with carbon dioxide and reuse them as an absorption liquid, reduce the amount of wastewater containing amine compounds, and a carbon dioxide recovery system equipped with the amine-containing concentration system.

[0005] Also known are carbon dioxide separation methods using solid adsorbents. For example, Patent Document 2 discloses a carbon dioxide capture device using a carbon dioxide adsorbent comprising a proton-type zeolite that adsorbs and supports a secondary amine. In this case, the adsorption performance is reduced due to competition between the moisture contained in the exhaust gas after combustion and the carbon dioxide. Therefore, it is necessary to provide a mechanism for drying the gas or the adsorbent in an upstream stage of the process.

[0006] However, in the carbon dioxide recovery systems and recovery devices disclosed in these patent documents, it is necessary to heat or cool the supply gas or the like using a boiler or a heat exchanger, which increases the required energy costs.

[0007] JP 2022-147624 A JP 2021-171744 A

[0008] The present disclosure has been made in light of the above-mentioned background, and provides a gas recovery device and a gas recovery method that can reduce energy costs.

[0009] According to one aspect of the present disclosure, there is provided a "gas recovery apparatus for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, the gas recovery apparatus including: a carbon dioxide separation section having a carbon dioxide separator and configured to separate the carbon dioxide from the supply gas; a steam supply section configured to supply steam to the carbon dioxide separation section and generate the steam to reduce the partial pressure of the carbon dioxide in the carbon dioxide separation section; and a control section configured to control the state or amount of the steam supplied from the steam supply section."

[0010] According to one aspect of the present disclosure, there is provided a gas recovery apparatus for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, the gas recovery apparatus including: a carbon dioxide separation section having a carbon dioxide separator and configured to separate the carbon dioxide from the supply gas; a supply gas supply section connected to the carbon dioxide separation section and configured to supply the supply gas to the carbon dioxide separation section; and a control section configured to control the state or amount of the supply gas supplied from the supply gas supply section.

[0011] According to one aspect of the present disclosure, there is provided a "gas recovery method for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, the gas recovery method including: a carbon dioxide separation step of separating the carbon dioxide from the supply gas in a carbon dioxide separation section having a carbon dioxide separator; and a steam supply step of supplying steam to the carbon dioxide separation section to generate the steam in order to reduce the partial pressure of the carbon dioxide in the carbon dioxide separation section, wherein a state or amount of the steam supplied in the steam supply step is controlled by a control unit."

[0012] According to one aspect of the present disclosure, there is provided a "gas recovery method for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, the gas recovery method including: a carbon dioxide separation step of separating the carbon dioxide from the supply gas in a carbon dioxide separation unit having a carbon dioxide separator; and a supply gas supply step connected to the carbon dioxide separation unit of supplying the supply gas to the carbon dioxide separation unit, wherein a state or amount of the supply gas supplied in the supply gas supply step is controlled by a control unit."

[0013] The present disclosure provides a gas recovery device and a gas recovery method that can reduce energy costs. For example, because the speed and amount of carbon dioxide that can be separated are limited depending on the performance of the gas separator, even if more gas than necessary is supplied, carbon dioxide may not be separated and may flow out downstream of the gas separator. Under such conditions, by appropriately controlling the supply amount of supply gas so that it does not become excessive, it is possible to reduce the power required for supply and the amount of heat required to humidify or dehumidify the supply gas, thereby reducing the energy costs required for carbon dioxide separation. Similarly, there are optimal steam supply amounts, pressures, and temperatures for desorbing carbon dioxide depending on the performance of the gas separator. By controlling the amount, pressure, and temperature of steam, it is possible to reduce the amount of heat supplied to supply water vapor, the amount of cold supplied to remove steam, and the power required to compress steam, thereby reducing the energy costs required for carbon dioxide separation.

[0014] It should be noted that the above effects are merely illustrative for the sake of convenience and are not limiting. In addition to or instead of the above effects, any effect described in this disclosure or an effect obvious to a person skilled in the art may be achieved.

[0015] FIG. 1 is a diagram showing a schematic configuration of a gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 2 is a block diagram showing an example of the configuration of a processing apparatus 8 according to an embodiment of the present disclosure. FIG. 3A is a diagram showing a processing flow executed in the processing apparatus 8 according to an embodiment of the present disclosure. FIG. 3B is a diagram showing a processing flow executed in the processing apparatus 8 according to an embodiment of the present disclosure. FIG. 4 is a diagram showing an operating state of the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 5 is a diagram showing an operating state of the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 6 is a diagram showing an operating state of the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 7A is a diagram showing a schematic configuration of a heat or cold energy supplier in the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 7B is a diagram showing a schematic configuration of a heat or cold energy supplier in the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 7C is a diagram showing a schematic configuration of a heat or cold energy supplier in the gas recovery apparatus 1 according to an embodiment of the present disclosure. FIG. 8 is a diagram showing a schematic configuration of a gas recovery apparatus 501 according to an embodiment of the present disclosure. FIG. 9 is a diagram showing the relationship between the amount of exhaust gas supply, energy cost, and carbon dioxide purity. FIG. 10 is a diagram showing the relationship between the amount of water vapor generated, the energy cost, and the purity of carbon dioxide.

[0016] Hereinafter, as an example of an embodiment of the present invention, a case where the present invention is applied to a gas recovery device will be described with reference to the accompanying drawings. Note that common components in the drawings are given the same reference numerals.

[0017] In this disclosure, "sorption" is synonymous with "absorption" and "adsorption," and refers to the chemical or physical attachment of carbon dioxide, moisture, steam, etc. to a material itself. For this reason, "sorption" is primarily used, but "absorption" or "adsorption" may also be used for convenience of explanation, although they do not differ in meaning as a reaction. Similarly, "release" is synonymous with "desorption," "detachment," and "diffusion," and refers to the separation of carbon dioxide, moisture, steam, etc. from a material itself. For this reason, "release" is primarily used, but "desorption," "detachment," and "diffusion" may also be used for convenience of explanation, although they do not differ in meaning as a reaction. Furthermore, "separation" refers to the separation of some components contained in a gas, and includes separation via the above-mentioned sorption and release, and separation where only some of the components permeate without undergoing sorption.

[0018] 1. Configuration of a Gas Recovery Apparatus 1 According to the Present Disclosure Fig. 1 is a diagram showing a schematic configuration of a gas recovery apparatus 1 according to one embodiment of the present disclosure. When describing with reference to the drawings, "upstream" refers to the side where gas or the like is input (supplied), and "downstream" refers to the side where gas or the like is output (discharged). First, the overall configuration of the gas recovery apparatus 1 will be described with reference to Fig. 1.

[0019] As shown in FIG. 1 , the gas recovery apparatus 1 is broadly composed of a feed gas supply unit 9, a humidity adjustment unit 2, a carbon dioxide separation unit 3, a steam supply unit 4, a carbon dioxide recovery unit 5, a residual gas discharge unit 6, a retained gas recovery unit 7, and a treatment device 8. The gas recovery apparatus 1 also has a plurality of pipes and valves (described later) between each unit. In this embodiment, a feed gas containing carbon dioxide is supplied to the carbon dioxide separation unit 3 via the humidity adjustment unit 2, and the carbon dioxide is sorbed in the carbon dioxide separation unit 3. The sorbed carbon dioxide is then released when steam is supplied to the carbon dioxide separation unit 3, causing a partial pressure drop. The carbon dioxide is separated from the feed gas, and concentrated carbon dioxide is recovered in the carbon dioxide recovery unit 5. The recovered carbon dioxide can be used appropriately in the vicinity of the gas recovery apparatus 1 or in a different facility. The flow of carbon dioxide recovery will be described in detail in the explanations that follow FIG. 4 .

[0020] As a more specific connection configuration, as shown in FIG. 1 , the gas recovery apparatus 1 includes a supply gas supply unit 9 to which a supply gas is supplied from one end (upstream side) thereof via an inlet pipe P11. The humidity adjustment unit 2 is connected to the other end (downstream side) of the supply gas supply unit 9. One end (downstream side) of the humidity adjustment unit 2 is connected to one end (upstream side) of the carbon dioxide separation unit 3 via a valve V1. Furthermore, one end (downstream side) of the steam supply unit 4 is connected to one end (upstream side) of the carbon dioxide separation unit 3 via a valve V2. More specifically, the humidity adjustment unit 2 and the steam supply unit 4 are connected at a connection point T1 via valves V1 and V2, and are connected to the carbon dioxide separation unit 3 via a common pipe P1. Note that, although a common pipe P1 is provided in the example of FIG. 1 , the pipe from the humidity adjustment unit 2 and the pipe from the steam supply unit 4 do not need to be a common pipe, and each pipe may be provided independently.

[0021] 1 , the steam supply unit 4 is connected to the upstream side of the carbon dioxide separation unit 3, but as a modified example, the steam supply unit 4 may be connected to the downstream side of the carbon dioxide separation unit 3 and configured to be able to supply steam from the downstream side of the carbon dioxide separation unit 3. Alternatively, the steam supply unit 4 may be connected to both the upstream and downstream sides of the carbon dioxide separation unit 3 and configured to be able to supply steam from the upstream and downstream sides of the carbon dioxide separation unit 3 according to the control of the treatment device 8.

[0022] When the carbon dioxide separation unit 3 is filled with a carbon dioxide absorbing material (such as the carbon dioxide separating material 33 described below), the carbon dioxide absorbing material located downstream within the carbon dioxide separation unit 3 may absorb less carbon dioxide than the carbon dioxide absorbing material located upstream. In this case, when removing the gas remaining in the carbon dioxide separation unit 3, if the recovered carbon dioxide is recovered from the upstream side of the carbon dioxide separation unit 3, carbon dioxide during recovery can be prevented from being absorbed downstream of the carbon dioxide separation unit 3, and the accumulated gas can be removed efficiently. On the other hand, when desorbing and recovering the absorbed carbon dioxide, by circulating steam from the downstream side of the carbon dioxide separation unit 3, the desorbed carbon dioxide can be prevented from being reabsorbed by the carbon dioxide absorbing material, and recovery can be performed efficiently. When steam is introduced from the downstream side of the carbon dioxide separation unit 3, a pipe can be provided to guide the gas flowing out from the upstream side to the carbon dioxide recovery unit 5.

[0023] As shown in FIG. 1 , the other end (downstream side) of the carbon dioxide separation unit 3 is connected to one end (upstream side) of the carbon dioxide capture unit 5 and the retained gas capture unit 7 via a valve V3. The other end (downstream side) of the carbon dioxide separation unit 3 is also connected to one end (upstream side) of the residual gas discharge unit 6 via a valve V4. More specifically, the carbon dioxide capture unit 5 and the residual gas discharge unit 6 are connected at a connection point T2 via valves V3 and V4, and are connected to the carbon dioxide separation unit 3 via a common pipe P2. Note that, although a common pipe P2 is provided in the example of FIG. 1 , the pipe to the valve V3 and the pipe to the valve V4 do not need to be shared, and each pipe may be provided independently. The retained gas capture unit 7 branches off from a connection point (branch point) T3 of a pipe P51 (a pipe from the valve V3 to the carbon dioxide capture unit 5) that connects the carbon dioxide separation unit 3 and the carbon dioxide capture unit 5. In other words, the carbon dioxide capture unit 5 and the retained gas capture unit 7 are connected at the connection point T3 and are commonly connected to the valve V3.

[0024] As shown in Fig. 1 , the other end (downstream side) of the carbon dioxide capture unit 5 is connected to the other end (upstream side) of the steam supply unit 4 via valve V5. This makes it possible to circulate the captured carbon dioxide in the carbon dioxide capture unit 5, steam supply unit 4, and carbon dioxide separation unit 3. In other words, the carbon dioxide capture unit 5, steam supply unit 4, and carbon dioxide separation unit 3 are connected to form a carbon dioxide circulation path. Note that a configuration in which such a circulation path is not formed (as an example, the configuration shown in Fig. 8 described below) is also possible.

[0025] Furthermore, as shown in FIG. 1 , a processing device 8 is electrically connected to each component, for transmitting control signals to the feed gas supply unit 9, humidity adjustment unit 2, carbon dioxide separation unit 3, steam supply unit 4, carbon dioxide recovery unit 5, residual gas discharge unit 6, and stagnant gas recovery unit 7 to control the operation of each component.

[0026] Next, a detailed configuration of each unit will be described with reference to Figures 1 and 2. Figure 2 is a block diagram showing an example of the configuration of a processing device 8 according to an embodiment of the present disclosure.

[0027] (Supply Gas Supply Unit 9) The supply gas supply unit 9 includes a pump 11 and a valve V10. One end (upstream side) of the pump 11 is connected to a common supply gas inlet pipe P11, and the other end (downstream side) is connected to the valve V10 via a pipe P12. A supply gas containing carbon dioxide is supplied to the pump 11 through the inlet pipe P11, and the supply gas is supplied to the humidity adjustment unit 2 via the pump 11, the pipe P12, and the valve V10. The pump 11 and the valve V10 are electrically connected to the processing device 8 and controlled based on a control signal transmitted from the processing device 8. With this configuration of the supply gas supply unit 9, supply gas in a state corresponding to the target supply state is supplied to the humidity adjustment unit 2 connected downstream of the supply gas supply unit 9. Specifically, the processing device 8 controls the drive amount of the pump 11, the opening degree of the valve V10, or a combination thereof, thereby controlling the state or amount of the supply gas supplied to the humidity adjustment unit 2. By controlling the output of the pump 11 using an inverter and / or controlling the opening of the valve V10, the minimum amount of gas required can be supplied, reducing the power costs of the pump 11 and the costs associated with heating, cooling, humidifying, and dehumidifying the gas.

[0028] As a modification, a mechanism for heating or cooling the supply gas may be provided in the inlet pipe P11 or upstream thereof, or a mechanism for recovering heat from the supply gas may be provided in the inlet pipe P11 or upstream thereof, or a heat exchanger for heating, cooling, or heat recovery may be provided in the inlet pipe P11 or upstream thereof.

[0029] Examples of the supply gas state include the temperature, pressure, and relative humidity of the supply gas, and examples of the target supply state include the target temperature, pressure, and relative humidity of the supply gas supplied to the humidity adjusting unit 2.

[0030] (Humidity Adjustment Unit 2) The humidity adjustment unit 2 is provided to adjust the relative humidity of the supply gas containing carbon dioxide. Adjusting the relative humidity in this manner promotes the sorption of carbon dioxide in the carbon dioxide separation unit 3. Methods for adjusting the relative humidity include temperature adjustment treatment by heating or cooling, humidity adjustment treatment by humidification or dehumidification, or a combination of these. However, as long as the supply gas has a relative humidity that can promote the sorption of carbon dioxide in the carbon dioxide separation unit 3, it may be sent to the carbon dioxide separation unit 3 in its original state or in its amount. Here, the relative humidity is the partial pressure of water vapor contained in the supply gas containing carbon dioxide at a predetermined temperature divided by the maximum water vapor partial pressure (saturated vapor pressure) that can be contained at that temperature.

[0031] As shown in FIG. 1 , the humidity adjustment unit 2 includes a heat exchanger 21, a gas-liquid separator 22, and a pump 23. More specifically, one end (upstream) of the heat exchanger 21 is connected to an inlet pipe P21 connected to the supply gas supply unit 9, and the other end (downstream) is connected to the gas-liquid separator 22 via a pipe P22. The gas-liquid separator 22 functions, for example, as a humidifier or humidity control unit. A specific example is a bubbler, which brings water and gas into contact with each other to adjust the dew point to the temperature of the gas. The gas-liquid separator 22 may include a gas-liquid separation device such as a mist trap. Furthermore, one end (upstream) of the pump 23 is connected to the supply water inlet pipe P23, and the other end (downstream) is connected to the gas-liquid separator 22 via a pipe P24. Furthermore, a valve V1 is connected to the downstream side of the gas-liquid separator 22 via a pipe P25. A pipe P26 for discharging wastewater to the outside is connected to the gas-liquid separator 22. The pipe P26 may be provided with a pump for draining water and / or a valve for controlling the drainage.

[0032] With the humidity adjustment unit 2 configured as described above, the carbon dioxide-containing feed gas introduced from the feed gas supply unit 9 is supplied to the heat exchanger 21 through the inlet pipe P21 without undergoing a drying process. The feed gas is heated or cooled by the heat exchanger 21 depending on the temperature of the feed gas, adjusted to a predetermined temperature range, and then supplied to the gas-liquid separator 22. This allows the temperature of the feed gas to be adjusted to a predetermined dew point temperature, for example, and humidity control. In this way, the gas-liquid separator 22 also functions as a humidity control device. The predetermined temperature range is determined based on the operating temperature of the carbon dioxide separation unit 3 in the gas recovery system 1. For example, it is 0 to 100°C. Therefore, when exhaust gas obtained by burning methane gas or the like is supplied at a high temperature, the exhaust gas (feed gas) is cooled by the heat exchanger 21, and depending on the moisture content, some of the water vapor contained in the feed gas is condensed and separated as water. On the other hand, a relatively low-temperature feed gas, such as atmospheric air, is heated by the heat exchanger 21 as necessary.

[0033] Furthermore, feed water is introduced into the gas-liquid separator 22 by driving the pump 23, and the amount of water vapor in the internal space of the gas-liquid separator 22 is adjusted to be close to the saturated water vapor amount. The temperature of the internal space of the gas-liquid separator 22 is determined according to the operating temperature of the carbon dioxide separation unit 3 in the gas recovery apparatus 1. Therefore, depending on the temperature and moisture content of the supply gas passing through the gas-liquid separator 22, moisture is added to the supply gas (humidification process) or removed from the supply gas (dehumidification process). For example, when moisture is added to the supply gas, the pump 23 is driven to supply feed water to the gas-liquid separator 22. On the other hand, when moisture is removed from the supply gas, the amount of water vapor in the internal space of the gas-liquid separator 22 exceeds the saturated water vapor amount, and therefore, the moisture that cannot be contained as water vapor in the internal space of the gas-liquid separator 22 is drained through the pipe P26. More specifically, when the water vapor is condensed and separated as water by the heat exchanger 21, the water is separated from the gas as condensed water in the gas-liquid separator 22, and the condensed water is discharged as wastewater. A mist trap may be provided downstream of the gas-liquid separator 22 (for example, in the pipe P26).

[0034] With the above-described configuration and function of the humidity adjustment unit 2, the temperature and moisture content of the supply gas passing through the gas-liquid separator 22 are adjusted, and the gas is sent out toward the valve V1 in a state close to the operating temperature of the carbon dioxide separation unit 3 in the gas recovery device 1 and with a relative humidity of 80% or higher. Note that a heat exchanger may be provided downstream of the gas-liquid separator 22 (for example, in the pipe P25). In this case, the temperature and humidity can be further adjusted.

[0035] As described above, it is important that the supply gas is heated or cooled by the heat exchanger 21, and that heat or cold is supplied to the heat exchanger 21 for the heating or cooling. Therefore, a heat source or cold source for heating or cooling is connected to the heat exchanger 21 via a pipe. That is, in this embodiment, the pipe functions as a heat or cold supplier. By supplying heat or cold from the heat source or cold source to the heat exchanger 21 via the pipe, it is possible to heat or cool the supply gas to a predetermined temperature range.

[0036] Although the above description has been given of a case in which piping connected to the heat exchanger 21 is used as a heat or cold supplier, other methods of configuring a heat or cold supplier are also possible. For example, the heat exchanger 21 itself, the heat exchanger 21 and its surrounding inlet piping P21 and piping P22, or the entire humidity adjustment unit 2 may be housed in a container that can be filled with heat or cold. Heat or cold is supplied to the container from a heat or cold source via the connected piping. In other words, the container and piping function as a heat or cold supplier. This allows for or assists in heating or cooling by the heat exchanger 21 and maintaining the temperature of the heated or cooled supply gas. Alternatively, the heat exchanger 21 or the gas-liquid separator 22 may be heated or cooled using traced piping or jacketed piping or a container. Similar methods of supplying heat or cold are also possible in the other heat exchangers and gas-liquid separators described herein.

[0037] The heat or cold source supplied to the heat or cold supplier can be, for example, a source external to the gas recovery apparatus 1. When it is necessary to heat or insulate the supply gas (maintaining a high temperature relative to the ambient temperature), the following heat sources can be used: heat from a power generation facility, heat from a factory or electrical facility, heat from a phase transition or compression of a gas or liquid (e.g., water or liquefied natural gas), sensible heat of the gas or liquid, heat from natural sources and the Peltier effect, and combinations thereof. Specifically, in power generation facilities and factory facilities, various reactions such as combustion, methanation, nuclear fusion, and nuclear fission occur in at least a portion of the facility, generating heat. In addition, in electrical facilities, heat is generated by driving various devices such as motors and compressors installed in at least a portion of the facility. Furthermore, liquefied natural gas, city gas, propane gas, air, water, and the like undergo phase transitions and compression during use, generating heat during these phase transitions and compression. These sensible heat sources can also be utilized. Natural sources of heat also exist, such as geothermal energy, hot springs, and sunlight. In this embodiment, the heat medium heated by these heat sources is supplied through a heat or cold heat supplier. Of the heat sources exemplified above, it is preferable to use the power generation facility, factory facility, or electrical facility in which the gas recovery device 1 is installed as the heat source from the viewpoint of the energy cycle.

[0038] Furthermore, as an example, the heat source or cold source of the heat or cold supplied to the heat or cold heat supplier can be derived from inside the gas recovery device 1. The gas recovery device 1 has a configuration that generates heat during operation. Typically, high-temperature residual gas, for example, around 60°C, is discharged from the residual gas discharge unit 6 depending on the operation conditions. When it is necessary to heat or keep the supply gas warm (maintain a high temperature state relative to the ambient temperature), this discharged residual gas can be supplied to the heat or cold heat supplier, thereby using the residual gas discharge unit 6 as a heat source and the residual gas discharged from the residual gas discharge unit 6 as a heat medium.

[0039] Furthermore, when it is necessary to cool or heat the supply gas (maintain a low temperature relative to the ambient temperature), at least one of the following cold sources can be used: naturally occurring cold; cold from a phase transition or expansion of a gas or liquid (for example, water or liquefied natural gas); cold as sensible heat possessed by a gas or liquid; cold from an endothermic reaction; cold from the Peltier effect or Joule-Thomson effect; and combinations thereof. Specifically, liquefied natural gas, city gas, propane gas, air, water, and the like undergo phase transitions or expansions during use, generating cold during such phase transitions or expansions. Natural sources of cold also exist, such as the atmosphere, rainwater, and river water. In this embodiment, a refrigerant cooled by one of these cold sources is supplied via a heat or cold energy supplier.

[0040] Furthermore, as an example of the heat or cold source for the heat or cold supplied to the heat or cold supplier, a source derived from within the gas recovery device 1 can be used. The gas recovery device 1 has a steam supply unit 4 that heats supply water to generate steam. In particular, the steam generator 41 of the steam supply unit 4 generates steam by heating the supplied supply water, and at this time, the heat medium is cooled by the supply water absorbing heat from the heat medium, thereby generating cold. Therefore, when it is necessary to cool or keep the supply gas warm (maintain a state at a lower temperature than the ambient temperature), the supply water supplied to the steam generator 41 can be used as a cold source.

[0041] In this embodiment, it is possible to provide multiple heat or cold energy suppliers, including the heat or cold energy supplier used in the humidity adjustment unit 2, but it is not necessary for any of the heat or cold energy suppliers to be able to supply both heat and cold energy; it is sufficient if they are able to supply at least one of heat and cold energy.

[0042] As described above, the humidity adjustment unit 2 only needs to be able to set the relative humidity of the carbon dioxide-containing supply gas within a desired range. For example, the number of heat exchangers 21 and the number of heat or cold energy suppliers are not limited to one, and may be multiple depending on the temperature adjustment of the supply gas, and the number can be adjusted appropriately. Furthermore, if the temperature of the supply gas and the operating temperature of the carbon dioxide separation unit 3 in the gas recovery device 1 are approximately the same, the heat exchangers 21 and the heat or cold energy suppliers may not be provided.

[0043] The relative humidity adjustment method is not particularly limited, and examples include a bubbling method in which humidity is adjusted by passing gas through water, a steam blowing method in which water vapor is blown into the air, a water spraying method in which water is sprayed and evaporated in the air, an evaporation method in which gas is passed through or between fillers or hollow fibers, etc. Furthermore, a mist trap or the like may be provided as necessary to accurately adjust the relative humidity.

[0044] (Carbon dioxide separation unit 3) The carbon dioxide separation unit 3 is a modularized device composed of, for example, a substantially cylindrical housing 31 and a carbon dioxide separation material 33 filled in an internal space 32 of the housing 31. That is, in the carbon dioxide separation unit 3, the carbon dioxide separation material 33 is used as a carbon dioxide separator. Furthermore, a plurality of these configurations may be installed in parallel or in series. The carbon dioxide separation unit 3 according to this embodiment is capable of sorbing and releasing carbon dioxide in a high-humidity state. Here, high humidity refers to, for example, a relative humidity of 80% or higher.

[0045] The housing 31 is made of a common plastic, metal, ceramic, or the like, and has a structure that allows the common pipe P1 to be connected to one end and a structure that allows the common pipe P2 to be connected to the other end. For example, the housing 31 may be provided with a concave joint, and the common pipes P1 and P2 may have convex joints connected to their ends that fit into the concave joint. In particular, when a vacuum decompression process is performed in the gas recovery device 1, it is necessary to select materials and a structure that can withstand the process.

[0046] The carbon dioxide separating material 33 is a material that can sorb carbon dioxide under predetermined sorption conditions and release carbon dioxide under predetermined release conditions. Here, the predetermined sorption conditions are, for example, a relative humidity of 80% or higher and a carbon dioxide gas partial pressure of 0.04 kPa to 100 kPa. On the other hand, the predetermined release conditions may be set so that the gas partial pressure is lower than the sorption conditions, or only the temperature is set higher than the sorption conditions, or the temperature may be set higher than the sorption conditions while the partial pressure is further lowered.

[0047] More specifically, the carbon dioxide separation material 33 has a reversible gas absorption ability, in which it sorbs carbon dioxide from a supply gas containing a predetermined amount of moisture and then releases the carbon dioxide in response to a change in temperature or gas partial pressure. In particular, the carbon dioxide separation material 33 is characterized by its ability to sorb carbon dioxide in a wet state. Furthermore, the carbon dioxide separation material 33 also has a reversible moisture absorption ability, in which it reversibly sorbs and releases moisture. To achieve these properties, the carbon dioxide separation material 33 may be, for example, a crushed bulk gel made of a predetermined polymer material, or a gel formed from a gel particle solution containing the polymer material. Alternatively, the carbon dioxide separation material 33 may be an ion exchange resin such as an anion exchange resin, a polymer containing amino groups or ammonium groups, or a porous material such as activated carbon, porous silica, fumed silica, zeolite, or MOF (metal-organic framework).

[0048] The predetermined polymer material may be, for example, (A) a polymer having a polymer chain containing a structural unit derived from a monofunctional monomer and a crosslinked structure derived from a polyfunctional monomer, and an amine derived from an amine-containing treatment liquid, or (B) a polymer having a polymer chain containing a structural unit derived from a monofunctional monomer having an amino group and a crosslinked structure derived from a polyfunctional monomer, but not containing a component derived from an amine-containing treatment liquid. The monofunctional monomer in embodiment (A) and the polyfunctional monomer in embodiment (B) may or may not have an amino group.

[0049] The specified polymer material selectively absorbs carbon dioxide by containing amino groups in at least one of the polymer structural units and the impregnated amine. Furthermore, heating causes phase transitions such as a decrease in pKa and an increase in hydrophobic interactions of hydrophobic groups, resulting in the release of absorbed acidic gases. That is, the specified polymer material has the reversible gas absorption ability to selectively and reversibly absorb carbon dioxide. Furthermore, the specified polymer material has low water absorption and swelling properties. Therefore, when used as a gas absorbent or gas separator, a sufficiently high volumetric filling factor can be achieved. Furthermore, by using the specified polymer material, a sufficient gas flow path can be secured in the carbon dioxide separation section, and the amount of heat required for the heating process for gas release can be kept low.

[0050] Furthermore, even when liquid water is added to the absorbent material, the gaps between the hydrated polymers are maintained, ensuring sufficient flow paths for water, and the subsequent flow of gas allows the water to be easily discharged and the gas to be introduced into the gaps. For these reasons, a specific polymer material can be effectively used as a gas absorption material for reversibly absorbing carbon dioxide, and this gas absorption material can be effectively used as a gas separation material for separating acidic gases from mixed gases.

[0051] Below, we will explain the average molecular weight of the polymer contained in a specified polymer material, the amount of each group when the polymer has an amino group or a hydrophobic group, the physical properties of the polymer, and the amine content when the polymer material contains an amine.

[0052] The proportion of monomers having amino groups in all monomers can be, for example, 5 to 100 mol%, or 30 to 100 mol%, or 50 to 90 mol%. When the polymer has hydrophobic groups, the amount of the hydrophobic groups can be, for example, 0 mol% to 95 mol%, or 5 mol% to 70 mol%, or 10 mol% to 43 mol%. The degree of crosslinking of the polymer can be, for example, 0 mol% to 50 mol%, or 5 mol% to 40 mol%, or 10 mol% to 30 mol%. When the polymeric material contains an amine, the content thereof can be, for example, 1 to 30 mmol / g, or 2 to 20 mmol / g, or 3 to 10 mmol / g of the dry weight of the polymer.

[0053] The degree of swelling of the polymer contained in a given polymer material can be evaluated, for example, by measuring the amount of water it contains when immersed in water for a long period of time.

[0054] The polymer contained in a predetermined polymer material can have a water content of, for example, 4 grams / gram polymer or less, 3 grams / gram polymer or less, or 2 grams / gram polymer or less when swollen with an excess amount of water. Here, the "water content" of a polymer refers to the value calculated by the following formula (1), where M1 is the weight of the wet polymer after adding an excess amount of water, leaving the polymer to stand overnight at room temperature, grinding it with a hand blender, and then removing the water by filtration using filter paper or a metal mesh, and M0 is the weight of the polymer after drying by freeze-drying or natural drying. Water content = (M1 - M0) / M0 (1)

[0055] The polymer material can have a reversible carbon dioxide absorption capacity per dry polymer weight of, for example, 15 mL / g or more, 30 mL / g or more, or 60 mL / g or more. This allows the polymer material to efficiently absorb and recover carbon dioxide contained in the exhaust gas when used in, for example, a gas recovery device that recovers carbon dioxide from exhaust gas.

[0056] In addition, the carbon dioxide separation material 33 may contain, in addition to the polymer material, other components such as moisture, a pKa adjuster, an absorption promoter, a diffusion promoter, a moisture absorbent, an antioxidant, a thermoplastic resin, or a filler.

[0057] The moisture can be incorporated into the gas absorbing material by intentionally adding water or water vapor, for example, and carbon dioxide gas or bicarbonate ions can also be added when adding moisture.

[0058] A pKa adjuster can be added, for example, during polymerization to adjust the pKa of the polymer after polymerization to a desired value. This allows for control of the type of gas absorbed by the polymer, the type of gas or liquid selectively permeating the gas absorption material, the permeation flux, the selectivity of the gas to be absorbed relative to other gases, and the like. As a pKa adjuster, for example, one capable of protonating or deprotonating the amino group of the polymer can be used. For example, an acid such as hydrochloric acid or a base such as sodium hydroxide can be used with the concentration adjusted appropriately according to the desired pKa. Furthermore, the crosslinking rate of the polyfunctional monomer can also adjust the local environment around the amine in the polymer, such as the polymer density, inter-amine distance, and polarity, to control the pKa of the amine, so the above-mentioned polyfunctional monomer may also be used as a pKa adjuster. Furthermore, the addition of hydrophobic monomers, alcohols, or hydrophilic polymers during polymerization can also adjust the local environment around the amine, such as the polymer density, inter-amine distance, and polarity, to control the pKa of the amine, so these may also be used as pKa adjusters.

[0059] The absorption enhancer is a compound that functions to promote absorption of acidic gases into the polymer of one embodiment. The diffusion enhancer is a compound that functions to promote diffusion of acidic gases from the polymer. In one embodiment, an absorption / diffusion enhancer having both absorption and diffusion enhancer functions may be used. These absorption enhancers, diffusion enhancers, and absorption / diffusion enhancers may also function as stabilizers that stabilize the gas absorbing material. The total content of the absorption enhancer, diffusion enhancer, and absorption / diffusion enhancer in the gas absorbing material of one embodiment can be, for example, 0.05 mL or more, or 0.1 mL or more per 1 g of solid content. The content of the absorption enhancer in the gas absorbing material can be, for example, 0.1 to 12 N, 1 to 10 N, or 3 to 9 N in terms of amine concentration.

[0060] A low molecular weight amine can be used as the absorption enhancer, diffusion enhancer, or absorption / diffusion enhancer. The molecular weight of the low molecular weight amine may be, for example, 61 to 10,000, or 75 to 1,000, or 90 to 500. The boiling point of the low molecular weight amine may be, for example, 80°C or higher, or 120°C or higher, or 150°C or higher, since this is practical and allows long-term use. To raise the boiling point, an amine-containing compound that has a moiety that forms a salt with a counter ion and is liquid, such as an ionic liquid, may be used.

[0061] The low molecular weight amine may contain any of a primary amino group, a secondary amino group, a tertiary amino group, an ammonium group, an imidazolium group, a guanidium group, a piperidium group, and a 2,2,6,6-tetramethylpiperidium group. The low molecular weight amine may contain a plurality of amino groups, ammonium groups, imidazolium groups, and guanidium groups, for example, 1 to 3. The secondary amino group or tertiary amino group may also be a cyclic amino group. Furthermore, the low molecular weight amine may contain a functional group other than an amino group, an ammonium group, an imidazolium group, or a guanidium group, for example, a hydroxyl group. The low molecular weight amine may be an oligomer of ethyleneimine. The low molecular weight amine may contain 0 to 2 hydroxyl groups. Examples of low molecular weight amines include amines having an amino group and a hydroxyl group, and amines having three amino groups, such as amines having a secondary amino group and a hydroxyl group. For example, an amine having a boiling point of 150° C. or higher and a secondary amino group and a hydroxyl group may be selected, since this can dramatically increase the amount of acidic gas emitted, particularly in the high concentration range, and is suitable for repeated use.

[0062] Examples of low molecular weight amines include ETA (Ethanol Amine), DMAE (2-(Dimethylamino)ethanol), and IPAE (Isopropylamino) DMAEA (2-(Dimethylamino)ethylamine), TMEDA (Tetramethy TM-1,4-DAB (Tetramethylenediamine), TM HAD ('N,N,N',N'-Tetramethyl-1,6-hexanediamine), DEOA (Diethanol amine), MDEOA (N-Methyldiethanolamine), DAMDPA (Diamino-N-methyl dipropyl amine), 1-2HE-PRLD (1-2 Hydroxy ethylene pyrrolidine), 1-2HE-PP (1-2 Hydroxyethylepiperidine), Bis(2DMAE)ER(Bis(2-dimethylaminoethyl) ether), e(PMDETA)(Pentamethyldiethylenetriamine), AEAE(2-(2-Aminoethylamino)et hanol), TAEA (Tris(2-aminoethyl)amine), DETA (diethylenetriamine), tetraethylene In particular, DMAE, IPAE, Bis(2DMAE)ER, 1-2HE-PRLD, 1-2HE-PP, TM-1,4-DAB, TMHAD, and PMDETA may be selected because they can increase the amount of acidic gas emitted, and among these, IPAE, Bis(2DMAE)ER, 1-2HE-PP, TM-1,4-DAB, TMHAD, and PMDETA may be selected because they have a relatively high boiling point and are difficult to evaporate, and IPAE, TM-1,4-DAB, TMHAD, and PMDETA may be selected because increasing their concentration can significantly increase the amount of acidic gas emitted, and IPAE, TMHAD, and PMDETA may be selected because they are easily available.

[0063] The moisture absorbent that can be used as an additive is, for example, one that, when made into a saturated aqueous solution, has a relative humidity of 80% or less at 25°C. Examples of such moisture absorbents include ions such as bromide ions, chloride ions, acetate ions, carbonate ions, bicarbonate ions, lithium ions, potassium ions, calcium ions, magnesium ions, and sodium ions. Examples of such moisture absorbents also include salts such as lithium bromide, lithium chloride, calcium chloride, potassium acetate, magnesium chloride, potassium carbonate, and sodium carbonate. When a moisture absorbent is added, the amount added can be, for example, 0.01 to 10% by mass based on the total amount of the gas absorbent material.

[0064] Antioxidants that can be used as additives are those that can suppress or prevent oxidation when added. Examples of such antioxidants include vitamin C (ascorbic acid), vitamin E (tocopherol), BHT (dibutylhydroxytoluene), BHA (butylhydroxyanisole), sodium erythorbate, propyl gallate, sodium sulfite, sulfur dioxide, hydroquinone, and derivatives thereof. When an antioxidant is added, the amount added can be, for example, 0.01 to 10% by mass based on the total amount of the gas-absorbing material.

[0065] The gas absorption material may contain a thermoplastic resin. This allows the thermoplastic resin to be kneaded with the polymer of one embodiment and other components added as needed to form pellets or a film. Known thermoplastic resins can be used. Examples include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers; liquid crystal polymers such as modified polyolefins, polyamides, thermoplastic polyimides, and aromatic polyesters; various thermoplastic elastomers such as polyphenylene oxide, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, polyethers, polyether ether ketones, polyetherimides, polyacetals, styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based, and polyester-based materials such as polyethyl lactate; polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based materials such as polyvinyl chloride and polyvinylidene chloride; and copolymers, blends, polymer alloys, and the like primarily composed of these materials. For example, polyolefin-based resins such as polyethylene can be selected. When the gas absorbing material contains a thermoplastic resin, the content of the thermoactive resin can be, for example, 10 to 40 mass % based on the total amount of the gas absorbing material.

[0066] The gas absorbing material may contain a filler. This can form voids in the gas absorbing material, promoting gas diffusion into the gas absorbing material and improving the reversible gas absorption rate and reversible absorption amount. Furthermore, by using a filler with gas adsorption ability, it is possible to achieve gas adsorption of the adsorbent in addition to the gas absorption of the absorbent material. It is known that gas adsorbents exhibit high reversible gas adsorption capacity at low humidity, and gas absorbing materials exhibit high gas absorption performance at high humidity. Therefore, by using a gas adsorbent as a filler, it is possible to realize a material with high reversible gas adsorption capacity over a wide range of humidity conditions. As the filler with gas adsorption ability, for example, materials with large pore areas, such as various types of activated carbon and zeolite, may be used. An adsorbent with particularly high carbon dioxide gas adsorption capacity may be selected and used. Furthermore, when the polymer material constituting the gas absorbing material is gelled due to the inclusion of water or is a pulverized product of a gelled polymer (polymer pulverization), the addition of a filler reduces the bulk, increasing the loading capacity and improving the reversible gas absorption capacity. As the filler, fine particles with a primary particle diameter of 1000 nm or less, as described below, are preferably used. Furthermore, the reversible gas absorption capacity can be further improved by pulverizing the gas absorbent material containing the pulverized polymer and the filler. The pulverization of the gas absorbent material containing the pulverized polymer and the filler can be carried out using a planetary ball mill using a bead mill or the like.

[0067] To promote gas diffusion into the absorbent material, a powdered filler may be selected. Alternatively, a filler having an average primary particle size of, for example, 1000 nm or less may be used. The primary particle size can be measured by transmission electron microscopy. In one embodiment, the fine particles having a primary particle size of 1000 nm or less may be composed solely of fine particles having a primary particle size of 1000 nm or less. The particle size can be an average primary particle size of 0.1 nm to 1000 nm, or 0.3 nm to 500 nm, or 0.5 nm to 300 nm, or 1 nm to 200 nm, or 1.5 nm to 100 nm, or 2 nm to 50 nm, or 2.5 nm to 25 nm. This ensures the formation of a gas diffusion phase in the molded body of the gas absorbent material, which tends to further improve the gas absorption and diffusion rates. The fine particles may be aggregates of primary particles. The aggregates preferably have a size of 100 nm to 200 μm, more preferably 500 nm to 100 μm, and most preferably 2.5 μm to 50 μm. Among fillers, those having a water contact angle of, for example, 70° or more may be used. The water contact angle may be 80° or more, 100° or more, 110° or more, 120° or more, 130° or more, or 140° or more.

[0068] Hereinafter, fine particles having a primary particle diameter of 1000 nm or less that can be used as a filler will be specifically described. Fine particles having a primary particle diameter of 1000 nm or less may be composed of an inorganic material, an organic material, or a combination of an organic material and an inorganic material. Furthermore, the fine particles may be water-repellent fine particles or hydrophilic fine particles, but water-repellent fine particles are preferred. When the fine particles are water-repellent fine particles, the voids formed by the fine particles are prevented from being blocked by the moisture contained in the gas absorption material, and the voids can function effectively as a gas diffusion phase.

[0069] Here, "water-repellent fine particles" refers to fine particles having a primary particle diameter of 1000 nm or less and a water contact angle of 70° or more. The "water contact angle" of fine particles refers to the contact angle with water measured on the surface of a fine particle deposition film formed from the fine particles. The water contact angle of the fine particle deposition film surface can be measured by static water contact angle measurement.

[0070] The water contact angle of the water-repellent microparticles is preferably 80° or more, more preferably 100° or more, even more preferably 110° or more, even more preferably 120° or more, particularly preferably 130° or more, and most preferably 140° or more.

[0071] The water-repellent fine particles having a primary particle diameter of 1000 nm or less may be fine particles that are water-repellent themselves, or may be base particles (base particles) whose surfaces have been imparted with water-repellent properties. Examples of fine particles whose surfaces have been imparted with water-repellent properties include coated fine particles in which a water-repellent coating is formed on the surface of a base particle, and surface-modified fine particles in which base particles have been surface-modified to impart water-repellent properties.

[0072] First, carbon black can be cited as an example of fine particles that are water-repellent in themselves. Examples of carbon black include acetylene black, furnace black, channel black, thermal black, lamp black, and ketjen black, with acetylene black being preferred.

[0073] Other examples of water-repellent fine particles include fine particles made of Knobel (registered trademark) (porous carbon, manufactured by Toyo Tanso Co., Ltd.), titanium oxide, mesoporous silica, etc. Furthermore, fine particles formed from a water-repellent organic material can also be used as fine particles that themselves have water repellency. Examples of water-repellent organic materials that can be used to form the particles include -(CA １ A ２ -CA ３ A ４ )-(wherein A １ ~A ４represents a hydrogen atom, a fluorine atom, a chlorine atom or a perfluoroalkyl group; A １ ~A ４ at least one of which is a fluorine atom). Specific examples of fluororesins include polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and other monomers, polychlorotrifluoroethylene (PCTFE), copolymers of chlorotrifluoroethylene and other monomers, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polytetrafluoropropylene (PTFP), etc. Examples of copolymers of tetrafluoroethylene and other monomers include perfluoroalkoxyalkane (PFA: tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer), perfluoroethylene propene copolymer (FEP: tetrafluoroethylene and hexafluoropropylene copolymer), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluorodioxole copolymer (TFE / PDD), etc. Examples of copolymers of chlorotrifluoroethylene and other monomers include ethylene-chlorotrifluoroethylene copolymer (ECTFE). These water-repellent organic materials may be used alone or in combination of two or more.

[0074] The base particles of the coated particles and surface-modified particles may be inorganic or organic particles, but inorganic particles are preferred. Furthermore, when the base particles are made of water-repellent particles themselves and are surface-modified to impart water-repellent properties with a water-repellent coating, the gas absorption rate and gas emission rate as well as the amount of gas absorbed and emitted can be improved.

[0075] Known inorganic particles can be used, including carbon blacks such as acetylene black, furnace black, channel black, thermal black, lamp black, and ketjen black; particles of inorganic compounds such as oxides, hydroxides, nitrides, halides, carbonates, sulfates, acetates, and phosphates of metal or semi-metal elements; and natural mineral particles. Examples of inorganic compounds of metal or semi-metal elements include lithium fluoride, calcium carbonate, calcium phosphate, calcium sulfate, calcium fluoride, barium sulfate, titanium dioxide (titania), zirconium dioxide (zirconia), aluminum oxide (alumina), aluminosilicates (alumina silicate, kaolin, kaolinite), and silicon oxide (silica, silica gel). Examples of natural minerals include talc and clay. Among these, particles made of carbon black and silicon oxide are preferred.

[0076] Known organic particles can be used, including particles made of styrene-based, acrylic-based, melamine-based, benzoguanamine-based, and silicone-based polymers. In this case, a filler can be used in combination, and for example, activated carbon or zeolite can be preferably used as the filler.

[0077] The water-repellent coating formed on the base particles can be made of the water-repellent organic materials listed above as examples of water-repellent materials that can be used to form microparticles, as well as coatings of organopolysiloxanes and organohydrogenpolysiloxanes. Examples of organopolysiloxanes include dialkylpolysiloxanes and alkylphenylpolysiloxanes, and examples of organohydrogenpolysiloxanes include alkylhydrogenpolysiloxanes. The alkyl groups in dialkylpolysiloxanes, alkylphenylpolysiloxanes, and alkylhydrogenpolysiloxanes may be linear, branched, or cyclic, but linear is preferred. The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6. Here, the two alkyl groups bonded to the silicon atom may be the same or different. Specific examples of organopolysiloxanes include dimethylpolysiloxane and methylphenylpolysiloxane, and specific examples of organohydrogenpolysiloxanes include methylhydrogenpolysiloxane.

[0078] Examples of surface modification methods for base particles include methods of introducing water-repellent groups such as alkyl groups and fluorinated alkyl groups onto the surfaces of base particles. The alkyl groups and fluorinated alkyl groups introduced into the base particles may be linear, branched, or cyclic, but are preferably linear. The number of carbon atoms in the alkyl groups and fluorinated alkyl groups is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10. The fluorinated alkyl groups may be fluorinated alkyl groups in which some of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms, or may be perfluoroalkyl groups in which all of the hydrogen atoms have been substituted with fluorine atoms.

[0079] Surface modification to introduce these water-repellent groups into base particles can be carried out using a silane coupling agent or a silane compound such as silazane. Examples of silane coupling agents include compounds represented by the following general formula (2): R1nSiX(4-n) ... (2) In general formula (2), X represents a hydrolyzable group that generates a silanol group upon hydrolysis, and R1 represents a group containing a water-repellent group. n is an integer from 1 to 3. The silane coupling agent represented by general formula (2) introduces water-repellent groups into base particles by reacting the silanol group or silyl group generated by hydrolysis of X with the functional group on the surface of the base particle.

[0080] In general formula (2), examples of the "hydrolyzable group that generates a silanol group" represented by X include alkoxy groups such as a methoxy group and an ethoxy group, and halogen groups. Examples of the water-repellent group in R1 include an alkyl group, a fluorinated alkyl group, and dimethylsiloxane. For descriptions and preferred ranges of the alkyl group and the fluorinated alkyl group, please refer to the descriptions and preferred ranges of the water-repellent group that can be introduced onto the surface of the base particle. The water-repellent group may be bonded directly to Si or may be bonded via a linking group.

[0081] n is an integer of 1 to 3, and preferably 1 or 2. When n is 2 or more, multiple R1s may be the same or different. When n is 2 or less, multiple Xs may be the same or different.

[0082] Examples of the silane coupling agent represented by general formula (2) include triethoxyalkylsilane, diethoxydialkylsilane, ethoxytrialkylsilane, trimethoxyalkylsilane, dimethoxydialkylsilane, methoxytrialkylsilane, trichloroalkylsilane, etc. Specific examples of the silane coupling agent include triethoxycaprylylsilane (triethoxy-n-octylsilane), octadecyltrichlorosilane, etc.

[0083] The formation of a water-repellent coating on the above-mentioned base particles and the surface modification treatment can be carried out according to a conventional method. Commercially available water-repellent microparticles include Microdispers-200 (manufactured by Techno Chemical Co., Ltd.), AEROSIL RY200, AEROSIL RY300, and AEROSIL R805 (all manufactured by Evonik), and Ketjenblack (manufactured by Lion Specialty Chemicals Co., Ltd.). The above-mentioned water-repellent microparticles may be used alone or in combination of two or more types.

[0084] The fine particles having a primary particle diameter of 1000 nm or less that can be used as a filler are not limited to water-repellent fine particles, but may be fine particles other than water-repellent fine particles, i.e., fine particles having a water contact angle of less than 70°. Furthermore, water-repellent fine particles may be used in combination with fine particles having a water contact angle of less than 70°. The fine particles having a water contact angle of less than 70° may have a water contact angle of 50° or less, 30° or less, or 10° or less. The lower limit of the water contact angle of the fine particles is 0°.

[0085] Examples of fine particles other than water-repellent fine particles include base particles of coated fine particles and surface-modified fine particles, but also include particles made of inorganic compounds of metal elements and semimetal elements and organic particles, and silicon oxide particles are preferred. These inorganic and organic particles may have an organic compound coating on their surfaces, or organic functional groups may be introduced. AEROSIL 200 (manufactured by Evonik) is a commercially available product of fine particles other than water-repellent fine particles.

[0086] The specific surface area of ​​the fine particles is 1 to 3000 m ２ / g, and 2.5 to 2750m ２ / g, and more preferably 5 to 2500m ２ / g. This ensures that a gas diffusion phase is formed in the molded article of the gas absorbing material, and the gas absorption rate and diffusion rate tend to be improved. The specific surface area of ​​the fine particles can be measured by the BET method.

[0087] The weight ratio of the polymer material to the fine particles (polymer material:fine particles) is preferably 95:5 to 5:95, more preferably 90:10 to 30:70, and even more preferably 80:20 to 50:50. Furthermore, the content of the polymer material in the gas absorbing material, in terms of solid content, is preferably greater than the content of the water-repellent fine particles. Furthermore, when the polymer material contains water and has gelled, or when the polymer material is a pulverized gelled polymer, adding a filler to the gas absorbing material reduces the bulk, increases the loading capacity, and improves the reversible gas absorption capacity. To effectively achieve this effect, the volume ratio of the gelled polymer or its pulverized product to the fine particles (gelled polymer or its pulverized product:fine particles) is preferably 99.9:0.1 to 98:2, more preferably 99.75:0.25 to 98.5:1.5, and even more preferably 99.5:0.5 to 99:1. By setting the ratio of the polymer material to the fine particles within the above range, the gas absorption rate and the gas diffusion rate tend to be higher. However, the gas absorption material of one embodiment is not limited to those containing fine particles having a primary particle diameter of 1000 nm or less. In other words, the gas absorption material of one embodiment does not need to contain fine particles having a primary particle diameter of 1000 nm or less.

[0088] In addition to the fine particles exemplified above, known fillers can be used for the gas absorption material of one embodiment. For example, activated carbon, zeolite, silica, fumed silica, hydrophobized silica, hydrophobized fumed silica, water-repellent silica, alumina, hydrophobized alumina, water-repellent alumina, boehmite, diatomaceous earth, oxides such as titanium oxide, iron oxide, zinc oxide, magnesium oxide, and metal ferrite, hydroxides such as aluminum hydroxide and magnesium hydroxide, carbonates such as calcium carbonate (light and heavy), magnesium carbonate, dolomite, and dawsonite, sulfates or sulfites such as calcium sulfate, barium sulfate, ammonium sulfate, and calcium sulfite, talc, mica, clay, glass fiber, Examples of suitable fillers include silicates such as calcium silicate, montmorillonite, and bentonite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; carbon such as carbon black, hydrophobic carbon black, water-repellent carbon black, graphite, and carbon fiber; and other materials such as iron powder, copper powder, aluminum powder, zinc oxide, molybdenum sulfide, boron fiber, potassium titanate, lead zirconate titanate, fluorinated resin powder, and Teflon® powder. Hydrophobic materials can also be selected and used to suppress water vapor condensation and dew condensation. Carbon fillers such as carbon black can also be selected and used. These fillers may have a primary particle diameter of 1000 nm or less or greater than 1000 nm. Furthermore, the gas absorption material of one embodiment may also include particles made of the same material as those exemplified as fine particles having a primary particle diameter of 1000 nm or less, but having a primary particle diameter of greater than 1000 nm. When the gas absorbing material contains a filler, the content of the filler can be, for example, 0.1 to 60 mass % based on the total amount of the gas absorbing material.

[0089] The gas absorbing material may contain a dispersion medium for suspending the polymer material of one embodiment and the additive. The other components that can be used in the gas absorbing material described above may be used alone or in combination of two or more.

[0090] The carbon dioxide separation material 33 is not limited to the above-mentioned specific polymer materials. For example, materials such as basic polymers, basic polymer gels (fine particles), or ion exchange resins can also be used. These materials also satisfy the following requirements: reversible sorption and release of carbon dioxide, reversible sorption and release depending on temperature and pressure, reversible sorption and release of water, and sorbing carbon dioxide in a wet state.

[0091] The amount of retained gas can be reduced by increasing the packing density of the carbon dioxide separating material 33 in the internal space 32 of the housing 31. Reducing the amount of retained gas allows for an increase in the carbon dioxide concentration during recovery. Furthermore, when a retained gas recovery unit 7 is used, the dimensions of the retained gas recovery unit 7 can be reduced. Furthermore, even when an operation is performed to purge retained gas from the carbon dioxide separation unit 3 by supplying a portion of the recovered carbon dioxide to the carbon dioxide separation unit 3, the amount of carbon dioxide supplied can be reduced, thereby minimizing carbon dioxide loss. On the other hand, if the packing density is too high, it will lead to increased pressure loss and even to the disappearance of the gas diffusion phase. Therefore, the packing density is preferably 10% to 95% by volume, and more preferably 20% to 80%.

[0092] (Steam Supply Unit 4) The steam supply unit 4 generates and supplies steam upstream or downstream of the carbon dioxide separation unit 3 in order to reduce the partial pressure of carbon dioxide in the carbon dioxide separation unit 3 and to sorb or condense steam (moisture) onto the carbon dioxide separation material 33. In particular, the steam supply unit 4 adjusts the state or amount of the generated steam so that, when the steam reaches the carbon dioxide separation unit 3, the pressure of the steam is equal to or greater than the saturated water vapor pressure at the temperature of the carbon dioxide separation material 33 inside at least a part of the carbon dioxide separation unit 3. Here, adjusting the state refers to adjusting the temperature, adjusting the humidity, or both. For example, the steam supply unit 4 may adjust the state of the supplied steam so that it becomes saturated steam in a partial region inside the carbon dioxide separation unit 3. Alternatively, the supplied steam itself may be saturated steam. When the saturated vapor pressure is exceeded, the water vapor condenses at that position to become liquid water, simultaneously releasing the latent heat of vaporization of water. This heat can be used as reaction heat for releasing carbon dioxide from the absorbent, which results in a reduction in the temperature drop of the absorbent during carbon dioxide release and an acceleration in the carbon dioxide release rate. Furthermore, when carbon dioxide is adsorbed, the temperature rises due to the supply of reaction heat associated with carbon dioxide adsorption, but the condensed water changes into water vapor, which absorbs the heat equivalent to the latent heat of vaporization, thereby reducing the temperature rise.

[0093] 1 , the steam supply unit 4 includes a steam generator 41 with a built-in heater, and a pump 42. More specifically, a valve V5 is connected to one end (upstream side) of the steam generator 41 via a pipe P41, and a valve V2 is connected to the other end (downstream side) via a pipe P42. Furthermore, a supply water introduction pipe P43 is connected to one end (upstream side) of the pump 42, and the steam generator 41 is connected to the other end (downstream side) via a pipe P44.

[0094] The steam generator 41 , the valve V 2 and the pump 42 are electrically connected to the processing device 8 and are controlled based on control signals transmitted from the processing device 8 .

[0095] With such a configuration of the steam supply unit 4, when the supply of supply gas is stopped, the pump 42 is driven, supplying supply water to the steam generator 41, and steam at a predetermined temperature is generated in the steam generator 41. The generated steam is then supplied to the carbon dioxide separation unit 3 via the pipe P42, the valve V2, and the common pipe P1. Here, the predetermined temperature is the same as or is determined according to the operating temperature of the carbon dioxide separation unit 3 in the gas recovery apparatus 1.

[0096] When steam is supplied to the carbon dioxide separation unit 3 by the steam supply unit 4, the carbon dioxide in the carbon dioxide separation unit 3 is diluted with the steam and the partial pressure decreases, so that the amount of pressure reduction by a pump, which will be described later, can be reduced. This reduces the cost of the pressure reduction, which also leads to a reduction in the overall cost of the gas recovery device 1 and the cost of recovering carbon dioxide.

[0097] Furthermore, by controlling the operating rate of the steam generator 41, the opening of the valve V2, the operating rate of the pump 42, or a combination of these, based on a control signal generated from the processing device 8 in accordance with the target steam supply state, it is possible to control the state or amount of steam generated in the steam supply unit 4, the state or amount of steam introduced from the steam supply unit 4 to the carbon dioxide separation unit 3, or a combination of these. This makes it possible to reduce the energy required for the recovery device, including the energy required for steam supply or steam removal, the power of the pump, or the power required for steam compression, and to reduce the overall energy cost of the gas recovery device 1.

[0098] An example of the state of the steam is the temperature and pressure of the steam. An example of the target supply state is the state of the steam generated in the steam supply unit 4, and the target temperature and pressure of the steam introduced from the steam supply unit 4 to the carbon dioxide separation unit 3. In this specification, the term "state" may also include the amount. The term "state or amount" may mean at least one of the temperature, pressure, and amount.

[0099] As described above, the steam supply unit 4 has a steam generator 41 with a built-in heater, which heats the supply water to generate steam. In other words, the state or amount of steam generated may be controlled by adjusting the amount of heat added by the steam supply unit 4 to the supply water. A heat source for supplying heat used to heat the supply water is connected to the steam generator 41 via a pipe. In other words, in this embodiment, the pipe functions as a heat or cold heat supplier. By supplying heat from the heat source to the steam generator 41 via the pipe, it is possible to heat the supply water to a predetermined temperature range.

[0100] Although the above description has been given of a case where the piping connected to the steam generator 41 is used as a heat or cold heat supplier, it is also possible to configure a heat or cold heat supplier by other methods. For example, the steam generator 41 itself, the steam generator 41 and its surrounding piping P41 and piping P42, or the entire steam supply unit 4 are housed in a container that can be filled with heat. Heat is then supplied from a heat source to the container via the connected piping. In other words, the container and the piping function as a heat or cold heat supplier. This makes it possible to maintain the temperature of the steam heated by the steam generator 41 or to assist in this.

[0101] The heat source of the heat or cold heat supplier can be derived from outside or inside the gas recovery device 1, similar to the heat exchanger 21. A detailed description is omitted here, as it is the same as the heat source of the heat exchanger 21.

[0102] The steam supply unit 4 may be incorporated into the humidity adjustment unit 2 described above. That is, the humidity adjustment unit 2 may include the steam supply unit 4, and the function of the steam supply unit 4 may be performed by the humidity adjustment unit 2. Depending on the rate at which carbon dioxide is released, the water vapor released from the carbon dioxide separating material 33 may be sufficient to lower the partial pressure of carbon dioxide. That is, in the relative humidity adjustment step and sorption step described below, the humidity of the supply gas is adjusted by the humidity adjustment unit 2 so that moisture is sorbed in advance by the carbon dioxide separating material 33, and the moisture can be used to lower the partial pressure of carbon dioxide and humidify the carbon dioxide in the release step described below.

[0103] (Carbon dioxide capture unit 5) As shown in Fig. 1 , the carbon dioxide capture unit 5 includes a pump 51, a heat exchanger 52, a gas-liquid separator 53, valves V51, V52, and V53, and a storage tank 54. More specifically, one end (upstream side) of the pump 51 is connected to a valve V3 via a pipe P51, and the other end (downstream side) is connected to a heat exchanger 52 via a pipe P52. The gas-liquid separator 53 is connected to the downstream side of the heat exchanger 52 via a pipe P53. The valve V51 is connected to the downstream side of the gas-liquid separator 53 via a pipe P54. The gas-liquid separator 53 is connected to a pipe P55 for sending wastewater to the outside.

[0104] As shown in Fig. 1, a degassing pipe P56 for degassing gases other than carbon dioxide (retained gases) is connected downstream of the valve V51. A pipe P57 is connected to the branch point T51 of the pipe P54, and one end of the valve V52 is connected downstream of the pipe P57. The other end (downstream) of the valve V52 is connected to the storage tank 54 via a pipe P58. The storage tank 54 is also connected to the valve V5 via a pipe P59.

[0105] Between the valve V52 and the storage tank 54, a branch pipe P50 is provided, branching from a branch point T52 of the pipe P58. A valve V53 is installed in the branch pipe P50. When the carbon dioxide concentration in the gas recovered from the carbon dioxide separation unit 3 is equal to or higher than a certain concentration, the recovered gas can be recovered via the valves V52 and V53. On the other hand, when the carbon dioxide concentration in the gas recovered from the carbon dioxide separation unit 3 is lower than a certain concentration, the gas can be discharged outside the device as retained gas via the valve V51. Alternatively, the retained gas may be supplied to the introduction pipe P11 as a supply gas and circulated thereby. To determine the carbon dioxide concentration, an analyzer for acquiring the carbon dioxide concentration may be provided between the carbon dioxide separation unit 3 and the branch point T51 (downstream of the carbon dioxide separation unit 3 and upstream of the branch point T51).

[0106] With the carbon dioxide capture unit 5 configured as described above, a portion of the gas capture apparatus 1 (for example, the carbon dioxide separation unit 3) is depressurized by driving the pump 51, and the introduced gas (carbon dioxide and water vapor) introduced toward the carbon dioxide capture unit 5 by this depressurization is heated or cooled by the heat exchanger 52 depending on the temperature of these gases, and the temperature is adjusted to a predetermined temperature range before being supplied to the gas-liquid separator 53. For example, when the introduced gas is cooled by the heat exchanger 52, the water vapor contained in the introduced gas is condensed and separated as water. Here, the predetermined temperature range is determined depending on the operating temperature of the carbon dioxide separation unit 3 in the gas capture apparatus 1. For example, the predetermined temperature range is −78°C to 60°C.

[0107] In the gas-liquid separator 53, moisture is removed from the introduced gas, and the removed moisture is discharged as wastewater through piping P55. More specifically, after the water vapor is condensed and separated into water by the heat exchanger 52, the water is separated from the gas as condensed water in the gas-liquid separator 53, and the condensed water is discharged as wastewater. Here, the heat exchanger 52 may also serve as the gas-liquid separator 53. A suction pump capable of discharging water may be provided in the piping P55. As a result, the moisture content of the introduced gas passing through the gas-liquid separator 53 is adjusted to increase the proportion of carbon dioxide, and the gas is supplied to the storage tank 54 via piping P54, branch point T51, piping P57, and valve V52. The carbon dioxide stored in the storage tank 54 is delivered to the steam supply unit 4 via piping P59, valve V5, and piping P41 at a predetermined timing described below. In other words, the carbon dioxide capture unit 5, the steam supply unit 4, the carbon dioxide separation unit 3, and the piping and valves connecting them constitute a carbon dioxide circulation path for circulating carbon dioxide.

[0108] The pump 51 , the valve V 3 , the heat exchanger 52 , the valve V 52 and the valve V 51 are electrically connected to the processing device 8 and are controlled based on control signals transmitted from the processing device 8 .

[0109] The above-described configuration and function of the carbon dioxide capture unit 5 not only adjusts the temperature of the carbon dioxide to be stored, but also removes unnecessary moisture, allowing highly concentrated carbon dioxide to be stored in the storage tank 54. If temperature adjustment is not required, the heat exchanger 52 need not be provided. Furthermore, the positional relationship between the pump 51 and the heat exchanger 52 may be reversed, and the temperature-adjusted introduced gas may be drawn in by the pump 51. In this manner, the gas can be cooled and water vapor removed by the heat exchanger 52 before the recovered gas is compressed by the pump 51, thereby reducing the capacity and power required for the pump 51. In this case, it is desirable that the pipe P55 be equipped with a suction pump capable of draining water from the reduced pressure environment. The suction pump may be, for example, a peristaltic pump. Furthermore, the number of pumps 51 and heat exchangers 52 is not limited to one, but may be multiple depending on the amount of introduced gas drawn in and the temperature adjustment, and the number can be adjusted appropriately. By dehumidifying, cooling, or further compressing the gas in multiple stages, the cost of the pumps and compression power required for concentrating carbon dioxide can be reduced. The storage tank 54 is not essential, and may be directly connected to a carbon dioxide reduction device (not shown). It is also possible to store the carbon dioxide as liquefied carbon dioxide or dry ice by pressurizing or cooling it as needed.

[0110] Furthermore, the state or amount of steam introduced from the steam supply unit 4 to the carbon dioxide separation unit 3 can be controlled by controlling the operating rate of the pump 51, the opening of the valve V3, the operating rate of the heat exchanger 52, or a combination of these, based on a control signal generated from the processing device 8 in accordance with the target steam supply state. This makes it possible to reduce the energy required for the recovery device, including the energy required for steam supply or steam removal, the power of the pump, or the power required for steam compression, and to reduce the overall energy cost of the gas recovery device 1.

[0111] As described above, the carbon dioxide recovery unit 5 heats or cools the introduced gas to a predetermined temperature range using the heat exchanger 52. Therefore, a heat source or cold source for heating or cooling is connected to the heat exchanger 52 via a pipe. That is, in this embodiment, the pipe functions as a heat or cold supplier. By supplying heat or cold from the heat source or cold source to the heat exchanger 52 via the pipe, it is possible to heat or cool the introduced gas to a predetermined temperature range.

[0112] Although the above description has been given of the case where piping connected to the heat exchanger 52 is used as a heat or cold supplier, it is also possible to configure a heat or cold supplier using other methods. For example, the heat exchanger 52 itself, the heat exchanger 52 and the surrounding inlet piping P52 and piping P53, or the entire carbon dioxide capture unit 5 are housed in a container that can be filled with heat or cold. Heat or cold is supplied to the container from a heat source or cold source via the connected piping. In other words, the container and piping function as a heat or cold supplier. This makes it possible to perform or assist heating or cooling by the heat exchanger 52 and maintaining the temperature of the heated or cooled inlet gas. As described above, the heat exchanger 52, the inlet piping P52, the piping P53, or the entire carbon dioxide capture unit 5 may be heated or cooled using tracing piping or jacketed piping or a container.

[0113] The heat source or cold source of the heat or cold supplied to the heat or cold heat supplier can be derived from outside or inside the gas recovery device 1, similar to the heat exchanger 21. A detailed description is omitted here, as it is the same as the heat source of the heat exchanger 21.

[0114] Instead of the storage tank 54 of the carbon dioxide capture unit 5, a pipe may be provided to directly supply the concentrated and captured carbon dioxide to another device (such as a carbon dioxide reduction device).

[0115] 1, the residual gas discharge section 6 includes a heat exchanger 61 and a gas-liquid separator 62. More specifically, one end (upstream side) of the heat exchanger 61 is connected to a valve V4 via a pipe P61, and the other end (downstream side) is connected to the gas-liquid separator 62 via a pipe P62. An exhaust pipe P63 for exhausting residual gas to the outside is connected to the downstream side of the gas-liquid separator 62. A pipe P64 for sending wastewater to the outside is connected to the gas-liquid separator 62.

[0116] With such a configuration of the residual gas discharge section 6, the unnecessary residual gas obtained by separating carbon dioxide from the supply gas in the carbon dioxide separation section 3 is heated or cooled by the heat exchanger 61 depending on the temperature of the residual gas, and the temperature is adjusted to a predetermined temperature range before being supplied to the gas-liquid separator 62. For example, when the introduced gas is cooled by the heat exchanger 61, water vapor contained in the residual gas is condensed and separated as water. Here, the predetermined temperature range differs depending on the environment in which the gas recovery device 1 is installed. In other words, the allowable temperature of the residual gas to be discharged differs depending on the environment, and the heat exchanger 61 is provided to accommodate this allowable temperature. For example, if the temperature must be 25°C or below to be discharged as residual gas, the temperature range may be set to 20°C or below, which is lower than 25°C.

[0117] In the gas-liquid separator 62, unnecessary moisture is removed from the residual gas, and the removed moisture is sent out as wastewater from the pipe P64. More specifically, when the water vapor is condensed and separated into water by the heat exchanger 61, the water is separated from the gas as condensed water in the gas-liquid separator 62, and the condensed water is discharged as wastewater. As a result, the moisture content of the residual gas passing through the gas-liquid separator 62 is adjusted and the residual gas is discharged to the outside of the gas recovery apparatus 1. Similar to the temperature adjustment described above, the adjustment of the moisture content also varies depending on the environment in which the gas recovery apparatus 1 is installed. In other words, the allowable moisture content of the residual gas to be discharged varies depending on the environment, and the gas-liquid separator 62 is provided to accommodate this allowable moisture content.

[0118] The valve V4 and the heat exchanger 61 are electrically connected to the processing device 8 and are controlled based on control signals sent from the processing device 8.

[0119] With the above-described configuration and function of the residual gas discharge unit 6, the temperature and moisture content of the residual gas passing through the heat exchanger 61 and the gas-liquid separator 62 are adjusted, and the residual gas is prepared for discharge and discharged to the outside of the gas recovery apparatus 1. The number of heat exchangers 61 is not limited to one, and multiple heat exchangers 61 may be used depending on the temperature adjustment of the residual gas, and the number can be adjusted appropriately. Furthermore, if there are no restrictions on the temperature and moisture content of the dischargeable residual gas, the residual gas may be discharged via the valve V4 without providing the heat exchanger 61 and the gas-liquid separator 62. Naturally, either the heat exchanger 61 or the gas-liquid separator 62 may be provided, and only the temperature or moisture content may be adjusted, and the adjusted residual gas may be discharged to the outside of the gas recovery apparatus 1.

[0120] Furthermore, the state or amount of the supply gas introduced from the supply gas supply unit 9 can be controlled by controlling the opening of the valve V4 based on a control signal generated from the processing device 8 in accordance with the target supply state of the supply gas. This reduces the energy costs of the recovery device 1, including the power of the pump 11 for supplying the supply gas and the energy for humidifying or dehumidifying the supply gas, and makes it possible to reduce the overall energy costs of the gas recovery device 1.

[0121] As described above, the residual gas discharge unit 6 heats or cools the residual gas to a predetermined temperature range using the heat exchanger 61. Therefore, a heat source or a cold source for heating or cooling is connected to the heat exchanger 61 via a pipe. That is, in this embodiment, the pipe functions as a heat or cold supplier. By supplying heat or cold from the heat source or the cold source to the heat exchanger 61 via the pipe, it is possible to heat or cool the introduced gas to a predetermined temperature range.

[0122] Although the above description has been given of a case in which piping connected to the heat exchanger 61 is used as a heat or cold supplier, it is also possible to configure a heat or cold supplier using other methods. For example, the heat exchanger 61 itself, the heat exchanger 61 and the surrounding inlet piping P61 and piping P62, or the entire residual gas discharge section 6 are housed in a container that can be filled with heat or cold. Heat or cold is supplied to the container from a heat source or cold source via the connected piping. In other words, the container and piping function as a heat or cold supplier. This makes it possible to perform or assist heating or cooling by the heat exchanger 52 and to maintain the temperature of the heated or cooled residual gas.

[0123] The heat source or cold source of the heat or cold supplied to the heat or cold heat supplier can be derived from outside or inside the gas recovery device 1, similar to the heat exchanger 21. A detailed description is omitted here, as it is the same as the heat source of the heat exchanger 21.

[0124] Alternatively, a part or all of the residual gas may be returned to the supply gas side (i.e., the inlet pipe P21). Furthermore, when multiple gas recovery devices are installed, a part or all of the residual gas may be supplied to another gas recovery device. This configuration can increase the carbon dioxide recovery rate, recycle the supply gas, and realize a two-stage process.

[0125] 1, the retained gas recovery unit 7 includes a buffer tank 71 and a valve V71. More specifically, one end (upstream side) of the valve V71 is connected to a pipe P71, which is connected to a pipe P51 at a connection point (branch point) T3. The other end (downstream side) of the valve V71 is connected to the buffer tank 71 via a pipe P72.

[0126] By opening valves V71 and V3, the stagnant gas remaining in the carbon dioxide separation unit 3 flows into the stagnant gas recovery unit 7. Here, stagnant gas refers to a gas containing carbon dioxide and unnecessary gases and having a low carbon dioxide concentration. This stagnant gas can be temporarily stored and is ultimately discharged to the outside via the carbon dioxide recovery unit 5 and the degassing pipe P56. The buffer tank 71 allows for quick depressurization during carbon dioxide recovery. Furthermore, by minimizing the amount of carbon dioxide mixed with the stagnant gas, the carbon dioxide concentration during recovery can be increased, thereby improving recovery efficiency. The connection position of the degassing pipe P56 is not limited to the above-described position. It may be connected to any of the pipes P72, P71, P51, P52, P53, P54, and P57, and the stagnant gas may be discharged to the outside using this connection configuration. Multiple degassing pipes P56 may also be provided. A separate pump from pump 51 may also be installed to discharge the stagnant gas.

[0127] The number of buffer tanks 71 is not limited to one, and may be multiple. When multiple buffer tanks 71 are provided, valves for driving the buffer tanks 71 individually may be provided.

[0128] Furthermore, although the stagnant gas recovery unit 7 was disposed at a position branching off from the pipe P51, it may also be disposed at a position branching off from the pipe P42. In other words, the stagnant gas recovery unit 7 is not limited to being disposed downstream of the carbon dioxide separation unit 3, and may also be disposed upstream. Even in this case, the stagnant gas in the carbon dioxide separation unit 3 can be recovered by utilizing the relationship between the internal pressure of the buffer tank 71 and the internal pressure of the carbon dioxide separation unit 3. Furthermore, the stagnant gas recovery unit 7 may be disposed both upstream and downstream of the carbon dioxide separation unit 3.

[0129] (Processing Device 8) Fig. 2 is a block diagram showing an example of the configuration of the processing device 8 according to an embodiment of the present disclosure. The processing device 8 does not need to include all of the components shown in Fig. 2, and may have a configuration in which some components are omitted, or may include other components.

[0130] The processing device 8 is typically a terminal device capable of wireless communication, such as a PLC, an industrial personal computer, a sequencer, a laptop computer, or a desktop computer, but is of course not limited to such devices. For example, the processing device 8 can be suitably applied to any device capable of executing the program according to the present disclosure, such as a smartphone, a feature phone, a personal digital assistant, a PDA, a portable game console, or a stationary game console.

[0131] 2, the processing device 8 includes an output interface 81, a processor 82, a memory 83 including RAM, ROM, or non-volatile memory (or HDD in some cases), a communication interface 84 including a communication processing circuit and an antenna, and an input interface 85 including a touch sensor and hard keys. These components are electrically connected to each other via control lines and data lines.

[0132] The output interface 81 functions as an output unit that outputs images captured by a camera (not shown) and various displays output by executing the program according to the present disclosure to devices such as a display or a printer in response to instructions from the processor 82. Such a display may be, for example, a liquid crystal display, an organic EL display, or electronic paper.

[0133] The processor 82 is configured as a CPU (e.g., a microcomputer) and functions as a control unit that controls other connected components based on various programs stored in the memory 83. Specifically, the processor 82 reads and executes programs for executing applications according to the present disclosure and programs for executing the OS from the memory 83. In the present disclosure, the processor 82 controls the operation of each pump, each heat exchanger, steam generator 41, and each valve shown in FIGS. 3A and 3B (details of the control will be described in FIGS. 4 to 6). The processor 82 may be configured as a single CPU, or may be configured as a combination of multiple CPUs and GPUs.

[0134] The memory 83 is composed of ROM, RAM, non-volatile memory, HDD, etc., and functions as a storage unit. The ROM stores instructions and commands for executing the application and OS according to the present disclosure as a program. The RAM is used to write and read data while the program stored in the ROM is being processed by the processor 82. The non-volatile memory is memory into which data is written and read as the program is executed, and the data written therein is retained even after the execution of the program has ended. In the present disclosure, the memory 83 particularly stores programs for controlling the operation of each pump and each valve (the details of the control will be described in Figures 4 to 6).

[0135] The communication interface 84 functions as a communication unit that transmits and receives information to and from each valve and each pump via a communication processing circuit and an antenna. The communication processing circuit performs processing to transmit control information (control commands) to each valve or each pump according to the progress of processing of programs and various information used in the gas recovery device 1.

[0136] The communication processing circuit processes based on a wideband wireless communication system such as the LTE system, but it is also possible to process based on a system related to narrowband wireless communication such as a wireless LAN such as IEEE802.11 or Bluetooth (registered trademark) or a system related to contactless wireless communication. In addition to wireless communication, wired communication can also be used.

[0137] The input interface 85 is composed of a touch panel, hard keys, etc., and functions as an input unit that accepts instruction inputs related to the execution of the program according to the present disclosure, operation inputs for registering various information, etc. The touch panel is arranged to cover the output interface 81, and transmits position coordinate information corresponding to image data output from the output interface 81 to the display to the processor 82. Known touch panel methods can be used, such as a resistive film method, a capacitive coupling method, and an ultrasonic surface acoustic wave method. In the present disclosure, the touch panel detects swipe and tap operations on each icon, etc. displayed on the output interface 81 by an indicator. Note that, although the present disclosure uses the input interface 85 provided in the processing device 8, it is also possible to use an input interface 85, such as a mouse, that is connected wirelessly or via a wire to a main body including the processor 82, etc.

[0138] 2. Flow of Carbon Dioxide Recovery by the Gas Recovery Apparatus FIGS. 3A and 3B are diagrams showing a process flow executed in a processing device 8 according to an embodiment of the present disclosure. Also, FIGS. 4, 5, and 6 are diagrams showing the operating state of a single-column gas recovery apparatus 1 according to an embodiment of the present disclosure. Specifically, FIGS. 3A and 3B show a process flow in which the processing device 8 controls valves, pumps, and the like in each step, and FIGS. 4 to 6 show the operating states of the gas recovery apparatus 1 under the above control. In particular, FIG. 4 is a diagram showing the initial stage of the carbon dioxide recovery flow, a process in which the moisture content of the supply gas is adjusted and the supply gas is introduced into the carbon dioxide separation unit 3. FIG. 5 is a diagram showing the middle stage of the carbon dioxide recovery flow, a rinsing process for increasing the carbon dioxide concentration in the carbon dioxide separation unit 3. FIG. 6 is a diagram showing the final stage of the carbon dioxide recovery flow, a process in which carbon dioxide sorbed in the carbon dioxide separation unit 3 is released and stored in a storage tank.

[0139] 3A , the processor 82 of the processing device 8 accepts an operation input from an operator via the input interface 85 and starts a series of processes for separating and recovering carbon dioxide from the supply gas by the gas recovery device 1 (S111). The processor 82 then generates control signals for adjusting the relative humidity and sorbing carbon dioxide, and transmits the control signals to each valve to open and close the valve (S112). Specifically, the processor 82 generates and transmits a control signal for driving the pump 11 and a control signal for opening valves V10, V1, and V4. Meanwhile, the processor 82 generates and transmits control signals for closing valves V2, V3, and V5. In other words, these control signals open valves V10, V1, and V4, and close valves V2, V3, and V5, thereby forming a gas flow path leading to the humidity adjustment unit 2, the carbon dioxide separation unit 3, and the residual gas discharge unit 6.

[0140] FIG. 4 shows the gas flow path leading to the humidity adjustment unit 2, the carbon dioxide separation unit 3, and the residual gas discharge unit 6, formed by opening valves V10, V1, and V4 and closing valves V2, V3, and V5 in response to the control signal. In this state, the pump 11 in the supply gas supply unit 9 is driven to supply a supply gas containing carbon dioxide and having a temperature of approximately 80°C to the supply gas supply unit 9 via the inlet pipe P11. The supply gas supplied from the supply gas supply unit 9 is supplied to the humidity adjustment unit 2 via the inlet pipe P21. Cold is supplied to the heat exchanger 21 from a cold source via a refrigerant in the pipe. Therefore, the supply gas supplied to the heat exchanger 21 is cooled to approximately 50°C. Here, it is assumed that the supply gas is a gas obtained by burning methane gas, has a carbon dioxide concentration of approximately 7%, and a moisture concentration of approximately 14%. Such a supply gas has a saturated water vapor pressure equivalent to 50°C at 1 atmosphere.

[0141] The cooled supply gas is introduced into the gas-liquid separator 22 via pipe P22. As described above, the supply gas has a saturated water vapor pressure equal to that of 50°C at 1 atmosphere, so condensed moisture is removed in the gas-liquid separator 22, and the removed moisture is discharged as wastewater from pipe P26. This completes the relative humidity adjustment process, in which the supply gas containing carbon dioxide is dehumidified to adjust its relative humidity. The supply gas from which moisture has been removed is then introduced into the carbon dioxide separation unit 3 via valve V1 and common pipe P1, with a relative humidity of 80% or more (for example, 99%).

[0142] When the supply gas is introduced into the carbon dioxide separation unit 3, only carbon dioxide is sorbed by the carbon dioxide separation material 33 due to the above-mentioned properties of the carbon dioxide separation material 33. Meanwhile, the supply gas from which carbon dioxide has been separated remains in the internal space 32 of the carbon dioxide separation unit 3. When the supply gas is further continuously introduced into the carbon dioxide separation unit 3, carbon dioxide continues to be sorbed by the carbon dioxide separation material 33, and the internal space 32 of the casing 31 is filled with the supply gas from which carbon dioxide has been separated. Then, when the supply gas is further continuously introduced into the carbon dioxide separation unit 3, carbon dioxide continues to be sorbed by the carbon dioxide separating material 33, but the supply gas from which carbon dioxide has been separated is discharged as residual gas to the residual gas discharge unit 6 via the common pipe P2, the valve V4, and the pipe P61. Here, the gas from the supply gas from which carbon dioxide has been separated that remains in the internal space 32 of the carbon dioxide separation unit 3 is referred to as retained gas.

[0143] This completes the sorption process in which carbon dioxide is sorbed onto the carbon dioxide separation material 33 from the supply gas whose moisture content has been adjusted. Here, sorption heat is generated when carbon dioxide is sorbed, causing the temperature of the supply gas to rise. This may result in a decrease in the carbon dioxide sorption performance of the carbon dioxide separation material 33, but the moisture in the carbon dioxide separator evaporates and causes vaporization and cooling, suppressing the temperature rise in the carbon dioxide separation section 3 and maintaining the carbon dioxide sorption performance of the carbon dioxide separation material 33. Furthermore, the sorption process does not require waiting until all of the absorbent reaches equilibrium with the carbon dioxide concentration of the supply gas, and the sorption time can be determined arbitrarily. The sorption time is determined based on the characteristics of the absorbent, the target recovery amount per hour, the purity of the recovered carbon dioxide, or the recovery rate.

[0144] Cold heat is supplied to the heat exchanger 61 from a cold heat source through a refrigerant in a pipe. Therefore, when the residual gas is introduced into the heat exchanger 61 of the residual gas discharge unit 6, the residual gas is cooled to approximately 24°C in the heat exchanger 61 so that the residual gas can be discharged from the gas recovery device 1. Here, the cooling temperature is not limited to 24°C, and it is assumed that the residual gas discharge condition requires that the temperature of the residual gas be room temperature.

[0145] The residual gas cooled to 24°C in the heat exchanger 61 is introduced into the gas-liquid separator 62 via pipe P62. Here, the residual gas contains a large amount of moisture because the relative humidity of the residual gas was approximately 80% or higher even when it was in the state of a supply gas (containing carbon dioxide). Therefore, the cooled residual gas contains a large amount of water vapor, and moisture is removed from the residual gas in the gas-liquid separator 62. The removed moisture is discharged as wastewater from pipe P64. Meanwhile, the residual gas from which moisture has been removed is discharged to the outside of the gas recovery device 1 via exhaust pipe P63.

[0146] The pressure in the path from the introduction of the supply gas to the separation by absorption of carbon dioxide and further to the discharge of the exhaust gas is approximately 1 atm. However, this pressure varies depending on the environment in which the gas recovery device 1 is used. For example, in a space probe, the pressure may be 0.5 atm, but on the other hand, there are also cases where the pressure exceeds 1 atm.

[0147] In the above description, the residual gas is cooled to approximately 24°C in the heat exchanger 61, but this cooling is not essential. For example, the residual gas may be used as a heat medium and supplied to at least one of the heat exchanger 21, the steam generator 41, and the heat exchanger 52 to be used for heating in the heat exchanger 21, the steam generator 41, and the heat exchanger 52. Alternatively, the heat recovered by the heat exchanger 61 may be compressed and heated by a heat pump, thereby efficiently heating the heat exchanger 21, the steam generator 41, and / or the heat exchanger 52.

[0148] 3A, once the gas flow path leading to the humidity adjustment unit 2, the carbon dioxide separation unit 3, and the residual gas discharge unit 6 is formed as shown in Fig. 4, the processor 82 of the processing device 8 starts monitoring the supply amount of the supply gas (S113). Specifically, the processor 82 calculates a target supply amount for the amount of supply gas supplied from the supply gas supply unit 9, and monitors whether the amount of supply gas currently being supplied has exceeded the target supply amount.

[0149] Here, the case of controlling the "supply amount of supply gas" will be described as a specific example of the supply state of the supply gas to be controlled. However, the temperature and pressure of the supply gas can also be controlled in the same manner based on the target supply temperature or target supply pressure.

[0150] As described above, the amount of carbon dioxide that can be sorbed by supplying the feed gas to the carbon dioxide separation unit 3 is affected by the characteristics of the absorbent, the target recovery amount per hour, the purity of the recovered carbon dioxide, or the recovery rate. Therefore, the processor 82 of the treatment device 8 acquires detected values ​​of the temperature, humidity, and pressure of the feed gas supplied to the carbon dioxide separation unit 3 using sensors installed upstream of the feed gas supply unit 9 (e.g., inlet pipes P21 and P25). The processor 82 also calculates the carbon dioxide absorption rate in the carbon dioxide separation unit 3 and the cumulative amount of carbon dioxide absorbed since the control signal of S112 was sent using sensors installed upstream of the residual gas discharge unit 6 (e.g., inlet pipe P2), downstream of the humidity adjustment unit 2 (e.g., pipe P1), or both. The processor 82 also acquires detected values ​​of the temperature and pressure inside the carbon dioxide separation unit 3 using sensors installed inside the carbon dioxide separation unit 3. The processor 82 also acquires detected values ​​of the temperature and humidity of the feed gas using sensors installed upstream of the carbon dioxide separation unit 3 (e.g., in the common pipe P1). The processor 82 also acquires detected values ​​of the temperature and humidity inside the humidity adjustment unit 2 using sensors installed inside the humidity adjustment unit 2. The processor 82 acquires these detected values ​​at predetermined times as needed, and calculates a target supply amount of the supply gas to be supplied from the supply gas supply unit 9 based on the acquired detected values.

[0151] As an example, the target supply amount of the supply gas is calculated as follows: Target supply amount at a predetermined timing = gas supply amount at the start of the sorption process × cumulative carbon dioxide sorption amount in the carbon dioxide separation section at a predetermined timing / maximum carbon dioxide sorption amount in the carbon dioxide separation section (Equation 1) Or, Target supply amount at a predetermined timing = gas supply amount at the start of the sorption process × {1 - (carbon dioxide concentration observed downstream of the carbon dioxide separation section at a predetermined timing / carbon dioxide concentration observed upstream of the carbon dioxide separation section)} (Equation 2)

[0152] Furthermore, the processor 82 acquires the values ​​of the output of the pump 11, the aperture of the valve V10, the degree of heating or cooling in the heat exchanger 21, the aperture of the valve V1, the amount of feed water supplied by driving the pump 23, the temperature of the feed water, and the aperture of the valve V4, and calculates the current amount of feed gas. As an example, the current amount of feed gas is calculated by providing a throttling mechanism such as a Pitot tube or an orifice and a pressure gauge at an arbitrary position upstream of the carbon dioxide separation unit 3 and converting it using a function. Alternatively, if necessary, the amount of feed gas is calculated using the drive frequency of the pump 11 controlled by an inverter or the like, the output of the pump 11 or a pressure value measured in the pipe P12 downstream of the pump 11, and a function approximating a characteristic diagram of the pump 11.

[0153] The processor 82 monitors the amount of supply gas being supplied as described above and determines whether the current amount of supply gas has exceeded the target supply amount (S114). If it is determined that the amount has exceeded the target supply amount, the processor 82 sends a control signal to the pump 11, the valve V10, the heat exchanger 21, the valve V1, the pump 23, the valve V4, or a combination thereof, and controls the amount of supply gas supplied from the supply gas supply unit 9 to be below the target supply amount (S115).

[0154] Specifically, when the target supply amount is exceeded, the output of the pump 11 is suppressed to prevent the pump 11 from operating excessively, thereby reducing unnecessary energy costs. Here, as one example, the pump 11 is connected to an inverter, and the inverter changes the rotation speed of a motor mounted on the pump 11, thereby controlling the output. As another example, the pump 11 is configured with multiple pumps connected in series, and the output is controlled by adjusting the number of pumps driven by a control signal. As yet another example, the pump 11 is configured with multiple pumps connected in series or in parallel with different outputs, and the output is controlled by adjusting the pumps driven and the number of pumps driven by a control signal.

[0155] Furthermore, if the target supply amount is exceeded, the openings of valves V10, V1, and V4 are reduced to increase the pressure loss in the valves and reduce the amount of gas supplied. The openings of valves V1 and V10 are, for example, controlled by adjusting the position and orientation of the internal flow control valves in response to a control signal from processor 82. The relationship between the valve openings and the supply amount of supply gas may be measured in advance, and the valve openings may be determined by referring to a characteristic curve created based on the measurement results.

[0156] Furthermore, if the target supply amount is exceeded, the amount of heat or cold energy added in the heat exchanger 21 is adjusted, or the output of the pump 23 is adjusted, thereby reducing the operating rates of the heat exchanger 21 and the pump 23 and reducing excess energy loss. The heat exchanger 21 is controlled by reducing the amount of energy added for heating or cooling and operating at a slower heating or cooling rate. The pump 23 is controlled in the same manner as the pump 11.

[0157] Here, the processor 82 only determines whether the target supply amount (upper limit) of the supply gas has been exceeded, but it is also possible to further determine whether the target supply amount (lower limit) of the supply gas has been exceeded, and to control the amount of supply gas to increase if it has been exceeded. If the supply amount of supply gas falls below the target supply amount (lower limit), the amount of carbon dioxide recovered will decrease. As a result, the carbon dioxide recovery efficiency will decrease. Therefore, by adjusting the supply amount of supply gas to an appropriate amount, it is possible to optimize the energy cost.

[0158] 3A, at the same timing as the above-described control, the processor 82 of the processing device 8 generates control signals for opening and closing the valves and transmits the control signals to each valve to open and close the valves. Specifically, the processor 82 generates control signals for opening valves V51 and V71 and transmits the control signals. Meanwhile, the processor 82 generates control signals for closing valve V52 and transmits the control signals. Thereafter, valves V51 and V71 open, and valve V52 closes. This forms a gas flow path leading to the retained gas recovery unit 7 and the carbon dioxide recovery unit 5. The processor 82 of the processing device 8 then generates a control signal for driving the pump 51 and transmits the control signal.

[0159] Here, the buffer tank 71 is filled with the retained gas that has been retained in the carbon dioxide separation unit 3 due to the previous carbon dioxide capture process (process that was executed before the supply of the above-mentioned supply gas). Therefore, a gas flow path leading to the retained gas capture unit 7 and the carbon dioxide capture unit 5 is formed, and when the pump 51 is driven, the retained gas that has been filled in the buffer tank 71 is introduced into the heat exchanger 52 via the pipe P72, the valve V71, the pipe P71, the pipe P51, the pump 51, and the pipe P52, and is then discharged to the outside of the gas capture device 1 via the exhaust pipe P56.

[0160] Furthermore, the processor 82 of the processing device 8 generates a control signal for controlling the temperature in the heat exchanger 52 to adjust the cooling temperature of the retained gas, and sends the control signal to the heat exchanger 52. Furthermore, cold is supplied to the heat exchanger 52 from a cold source through a refrigerant in a pipe. Therefore, when the retained gas is introduced into the heat exchanger 52 of the carbon dioxide recovery unit 5, the remaining gas is cooled to approximately 24°C in the heat exchanger 52 to make it possible to discharge the retained gas from the gas recovery device 1. Here, the cooling temperature is not limited to 24°C, and it is assumed that the discharge condition of the retained gas requires that the temperature of the retained gas be room temperature.

[0161] The stagnant gas cooled to 24°C in the heat exchanger 52 is introduced into the gas-liquid separator 53 via pipe P53. The stagnant gas contains a large amount of moisture because its relative humidity was approximately 80% or higher even when it was in the supply gas state (containing carbon dioxide). Therefore, the cooled stagnant gas contains a large amount of water vapor, and moisture is removed from the stagnant gas in the gas-liquid separator 53. The removed moisture is discharged as wastewater through pipe P55. Meanwhile, the stagnant gas from which moisture has been removed is discharged to the outside of the gas recovery apparatus 1 via pipe P54, valve V51, and degassing pipe P56. The pressure in the path from the buffer tank 71 to the degassing pipe P56 is approximately 0 atm, which is significantly smaller than the pressure in the exhaust gas discharge section.

[0162] By discharging the retained gas as described above, the inside of the buffer tank 71 is put into a vacuum state, and the retained gas can be temporarily stored in the process described below.

[0163] Next, the processor 82 obtains the time since the control signal of S112 was generated from a timer (not shown) mounted on the processing device 8, and determines whether the obtained time has reached the sorption time (S116). Note that this sorption time is determined based on the characteristics of the absorbent material, the target recovery amount per hour, the purity of the recovered carbon dioxide, or the recovery rate. If the sorption time has not been reached, monitoring of S113 continues.

[0164] When it is determined that the sorption time has been reached, the processor 82 generates control signals for opening and closing the valves and transmits the control signals to each valve to open and close the valves (S117). Specifically, the processor 82 generates control signals for closing valves V10, V1, and V4 and transmits the control signals. On the other hand, the processor 82 generates control signals for opening valves V2, V3, and V5 and transmits the control signals. That is, these control signals close valves V10, V1, and V4 and open valves V2, V3, and V5. Here, valves V51 and V71 are maintained in an open state, and valve V52 is maintained in a closed state. This forms a gas flow path leading to the storage tank 54 of the carbon dioxide capture unit 5, the steam supply unit 4, the carbon dioxide separation unit 3, and the carbon dioxide capture unit 5. Also formed are gas flow paths leading to the storage tank 54 of the carbon dioxide capture unit 5, the steam supply unit 4, the carbon dioxide separation unit 3, and the retained gas capture unit 7.

[0165] 5 shows the gas flow path formed by the control signal, which leads to the storage tank 54 of the carbon dioxide capture unit 5, the steam supply unit 4, the carbon dioxide separation unit 3, and the carbon dioxide capture unit 5, as well as the gas flow path formed by the control signal, which leads to the storage tank 54 of the carbon dioxide capture unit 5, the steam supply unit 4, the carbon dioxide separation unit 3, and the accumulated gas capture unit 7. In this state, the processor 82 of the processing device 8 generates a control signal and transmits the control signal to the pump 42. This drives the pump 42, supplying the supply water to the steam generator 41 via the pipe P43, the pump 42, and the pipe P44. Heat is supplied to the steam generator 41 from the heat source through the heat medium in the pipe. Therefore, the supply water is heated in the steam generator 41, and steam is generated. Note that the pump 51 continues to operate. In addition, the steam generated in the steam generator 41 may be supplied to at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61, and used for heating or cooling in each of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61.

[0166] Because the buffer tank 71 is in a vacuum state, the stagnant gas remaining in the carbon dioxide separation unit 3 is introduced into the buffer tank 71 via the common pipe P2, valve V3, pipe P51, pipe P71, valve V71, and pipe P72. This allows the stagnant gas to be quickly removed from the carbon dioxide separation unit 3, and the steam generated in the steam generator 41 and the carbon dioxide stored in the storage tank 54 are drawn into the carbon dioxide separation unit 3. Specifically, steam is introduced into the carbon dioxide separation unit 3 via pipe P42, valve V2, and common pipe P1, and carbon dioxide is introduced into the carbon dioxide separation unit 3 via pipe P59, valve V5, pipe P41, the steam generator 41, pipe P42, valve V2, and common pipe P1. That is, the steam and carbon dioxide are introduced into the carbon dioxide separation unit 3 via the same gas path from some point along the way. This allows the carbon dioxide to be humidified before being supplied to the carbon dioxide separation unit 3, preventing the absorbent from drying out.

[0167] Thereafter, when the buffer tank 71 is filled with retained gas, the pump 51 is driven to introduce the retained gas remaining in the carbon dioxide separation unit 3 into the heat exchanger 52 via the common pipe P2, the valve V3, the pipe P51, the pump 51, and the pipe P52. Here, the buffer tank 71 first transitions from a vacuum state to a state filled with retained gas, thereby mitigating sudden pressure changes in the pump 51. This reduces the load on the pump 51 and prevents breakdowns. The processor 82 of the processing device 8 then generates a control signal to close the valve V71 and transmits this control signal. This isolates the buffer tank 71, thereby improving the rate at which retained gas is removed.

[0168] Furthermore, the processor 82 of the processing device 8 continuously controls the temperature inside the heat exchanger 52 to about 24° C. Specifically, cold heat is supplied to the heat exchanger 52 from a cold heat source through a refrigerant in a pipe. Therefore, when the retained gas is introduced into the heat exchanger 52 of the carbon dioxide recovery unit 5, the remaining gas is cooled to about 24° C. in the heat exchanger 52 so that the retained gas can be discharged from the gas recovery device 1.

[0169] The stagnant gas cooled to 24°C in the heat exchanger 52 is introduced into the gas-liquid separator 53 via pipe P53. Here, the stagnant gas contains a large amount of moisture because the relative humidity of the stagnant gas was approximately 80% or higher even when it was in the state of a supply gas (containing carbon dioxide). Therefore, the cooled stagnant gas contains a large amount of water vapor, and moisture is removed from the stagnant gas in the gas-liquid separator 53. The removed moisture is discharged from pipe P55 as wastewater. Meanwhile, the stagnant gas from which moisture has been removed is discharged to the outside of the gas recovery device 1 via pipe P54, valve V51, and degassing pipe P56.

[0170] Meanwhile, in the carbon dioxide separation unit 3, the retained gas is discharged and steam increases. Furthermore, by maintaining a relative humidity of 80% or more, the carbon dioxide introduced into the carbon dioxide separation unit 3 is sorbed onto the carbon dioxide separating material 33, and release of carbon dioxide due to a drop in the carbon dioxide partial pressure at this point is prevented. This completes the removal of impurities in the carbon dioxide separation unit 3 (in other words, the rinsing process) while maintaining the amount of carbon dioxide sorbed in the carbon dioxide separation unit 3. During the rinsing process, the pressure in the passage through which the retained gas passes is a predetermined value that is equal to or lower than the saturated water vapor pressure at the operating temperature of the carbon dioxide separation unit 3.

[0171] Incidentally, instead of reducing the pressure in the rinsing step (the above-mentioned rinsing treatment) and drawing the carbon dioxide into the carbon dioxide separation section 3, the carbon dioxide may be supplied to the carbon dioxide separation section 3 at approximately 1 atm after the above-mentioned sorption step. In this case, a pump can be installed in pipe P41 or pipe P42 as necessary. This also makes it possible to expel stagnant gas from the internal space 32 of the carbon dioxide separation section 3 before reducing the pressure. In this case, the buffer tank 71 is also useful because it can quickly reduce the pressure. However, in this case, since high-purity carbon dioxide is stored inside the buffer tank 71, the gas inside the buffer tank 71 can also be recovered. Whether this rinsing step is performed after or before reducing the pressure can be determined arbitrarily in consideration of the characteristics of the absorbent material, the stable operation of the apparatus, etc.

[0172] Furthermore, since the purpose of the rinsing step is to remove stagnant gas present in the voids within the internal space of the carbon dioxide separation section 3, carbon dioxide and steam can be flowed in amounts sufficient to remove the stagnant gas. For example, carbon dioxide and steam can be flowed in amounts 0.1 to 10 times the column volume. Generally, the more the amount of flow, the less stagnant gas remains in the internal space 32, but the greater the loss of carbon dioxide. Therefore, an appropriate amount is determined based on the target recovery amount and recovery purity. Furthermore, depending on the relationship between the carbon dioxide concentration of the supply gas and the carbon dioxide concentration of the gas used for rinsing, some of the carbon dioxide may be sorbed onto the absorbent, or some of the carbon dioxide sorbed onto the absorbent may be released.

[0173] 3A, the processor 82 obtains the time since the control signal of S117 was generated from a timer (not shown) mounted on the processing device 8, and determines whether the obtained time has reached a predetermined rinse completion time (S118). If the rinse completion time has not been reached, the same processing is continued until the time is reached. The completion of the rinse step can also be determined by whether the carbon dioxide concentration obtained by a sensor installed downstream of the carbon dioxide absorption unit 3 (for example, in the pipe P2) has become higher than a predetermined value.

[0174] When it is determined that the rinsing completion time has been reached, the processor 82 of the processing device 8 generates control signals for opening and closing the valves and transmits the control signals to each valve to open and close the valves (S119). Specifically, the processor 82 generates control signals for closing valves V5 and V51 and transmits the control signals. On the other hand, the processor 82 generates a control signal for opening valve V52 and transmits the control signal. In other words, these control signals close valves V5 and V51 and open valve V52. Here, the other valves are maintained in an open or closed state. This forms a gas flow path leading to the steam supply unit 4, the carbon dioxide separation unit 3, and the carbon dioxide capture unit 5.

[0175] 6 shows the gas flow path formed by the control signal, leading to the steam supply unit 4, the carbon dioxide separation unit 3, and the carbon dioxide capture unit 5. In this state, the pump 42 continues to operate, so that feedwater is supplied to the steam generator 41 via the pipe P43, the pump 42, and the pipe P44, and steam is continuously generated in the steam generator 41. Furthermore, because the pump 51 continues to operate, the generated steam continues to be introduced into the carbon dioxide separation unit 3. As a result, the partial pressure of carbon dioxide in the carbon dioxide separation unit 3 decreases, and carbon dioxide is released from the carbon dioxide separation material 33. When carbon dioxide is released, the temperature of the carbon dioxide separation material 33 decreases due to reaction heat. This may also result in a decrease in the carbon dioxide release performance of the carbon dioxide separation material 33. However, as the temperature decreases, the pressure of the steam becomes equal to or exceeds the saturated water vapor pressure at the temperature of the carbon dioxide separation material 33 inside at least a portion of the carbon dioxide separation unit 3 (i.e., in the vicinity of the carbon dioxide separation material 33). Therefore, a portion of the steam supplied from the steam supply unit 4 is sorbed or condensed on the carbon dioxide separation material 33. Therefore, the latent heat of vaporization generated when part of the steam condenses into water is supplied to the carbon dioxide separating material 33, suppressing the temperature drop described above. In other words, the reaction heat generated by the release of carbon dioxide and the latent heat of vaporization generated by the condensation of the steam cancel each other out, and the carbon dioxide release performance of the carbon dioxide separating material 33 is maintained.

[0176] The released carbon dioxide, together with steam, is introduced into the heat exchanger 52 via the common pipe P2, valve V3, pipe P51, pump 51, and pipe P52 by reducing the pressure by driving the pump 51. This completes the release step in which steam is supplied to the carbon dioxide separating material 33 to reduce the partial pressure of carbon dioxide, and the steam is sorbed or condensed onto or into the carbon dioxide separating material 33 to release carbon dioxide from the carbon dioxide separating material 33.

[0177] At this time, the processor 82 of the processing device 8 generates a control signal for controlling the temperature in the heat exchanger 52 in order to adjust the cooling temperature of the carbon dioxide, and sends the control signal to the heat exchanger 52. Cold is supplied to the heat exchanger 52 from a cold source via a refrigerant in a pipe. Therefore, when the carbon dioxide and steam are introduced into the heat exchanger 52 of the carbon dioxide recovery unit 5, they are cooled to a predetermined temperature by the heat exchanger 52 in order to remove the steam from the carbon dioxide.

[0178] The carbon dioxide and steam cooled in the heat exchanger 52 are introduced into the gas-liquid separator 53 via pipe P53. Here, some moisture is removed in the gas-liquid separator 53. As a result, the gas passing through the gas-liquid separator 53 has an increased carbon dioxide concentration. The carbon dioxide that has passed through the gas-liquid separator 53 is then introduced into the storage tank 54 via pipe P54, pipe P57, valve V52, and pipe P58. As a result, high-concentration carbon dioxide (concentrated carbon dioxide) is stored in the storage tank 54. This completes the recovery process of recovering carbon dioxide released from the carbon dioxide separating material 33 while removing steam. In this recovery process, the pressure in the carbon dioxide recovery path upstream of the pump 51 is a predetermined value equal to or lower than the saturated water vapor pressure at the operating temperature, and is at or above environmental pressure downstream of the pump 51.

[0179] 3B , when a gas flow path leading to the steam supply unit 4, the carbon dioxide separation unit 3, and the carbon dioxide capture unit 5 is formed as shown in FIG. 6 , the processor 82 of the processing device 8 starts monitoring the supply amount of steam generated in the steam supply unit 4 or supplied from the steam supply unit 4 (S131). Specifically, the processor 82 calculates a target supply amount for the amount of steam generated in the steam supply unit 4 or the amount of steam supplied from the steam supply unit 4 to the carbon dioxide separation unit 3, and monitors whether the amount of steam currently being generated or currently being supplied has exceeded the target supply amount.

[0180] Here, the case of controlling the "steam supply amount" will be described as a specific example of the controlled steam supply state. However, the same processing can be performed based on the target supply temperature or target supply pressure when controlling the steam temperature or pressure.

[0181] As an example of this monitoring, the processor 82 of the processing device 8 calculates the carbon dioxide release rate in the carbon dioxide separation unit 3, or the integrated amount of carbon dioxide recovered since the control signal of S119 was transmitted, using a sensor installed downstream of the carbon dioxide separation unit 3 (for example, on the pipe P53). The processor 82 also acquires detected values ​​of the temperature and pressure inside the carbon dioxide separation unit 3 using a sensor installed inside the carbon dioxide separation unit 3. The processor 82 also acquires detected values ​​of the flow rate, temperature, and pressure of the steam supplied from the steam supply unit 4 to the carbon dioxide separation unit 3 using a sensor installed in the pipe between the steam supply unit 4 and the carbon dioxide separation unit 3. The processor 82 also acquires detected values ​​of the temperature and pressure inside the steam supply unit 4 using a sensor installed inside the steam supply unit 4. The processor 82 acquires these detected values ​​at predetermined timings as needed, and calculates a target supply amount of steam generated in the steam supply unit 4 or steam supplied from the steam supply unit 4 based on the acquired detected values.

[0182] As an example, the target steam supply amount is calculated as follows: Target steam supply amount at a predetermined timing = Steam supply amount at the start of the carbon dioxide capture process × Integrated amount of carbon dioxide released from the carbon dioxide separation section from the start of the carbon dioxide capture process to the predetermined timing / Maximum amount of carbon dioxide sorption in the carbon dioxide separation section... (Equation 3) Alternatively, as an example, the target steam supply amount can be determined as follows so as to keep the carbon dioxide partial pressure at the outlet of the carbon dioxide separation section constant: Target steam supply amount at a predetermined timing = Carbon dioxide desorption rate from the carbon dioxide separation section at the predetermined timing / Carbon dioxide desorption rate from the carbon dioxide separation section at the start of the carbon dioxide capture process × Steam supply amount at the start of the carbon dioxide capture process... (Equation 4)

[0183] Furthermore, the processor 82 acquires values ​​of the degree of heating in the heater of the steam generator 41, the opening of the valve V2, the pressure upstream of the valve V2, the pressure downstream of the valve V2, the amount of feed water supplied by driving the pump 42, the output of the pump 51, the opening of the valve V3, and the degree of heating or cooling in the heat exchanger 52, and calculates the amount of steam currently being generated in the steam supply unit 4 or the above amount currently being supplied from the steam supply unit 4. The current amount of steam is calculated, for example, by providing a throttling mechanism such as a Pitot tube or an orifice and a pressure gauge before and after the valve V2 and converting it using a function.

[0184] The processor 82 monitors the amount of steam generated or supplied as described above and determines whether the current amount has exceeded the target supply amount (S132). If it is determined that the current amount has exceeded the target supply amount, the processor 82 sends control signals to the steam generator 41, the valve V2, the pump 42, the pump 51, the valve V3, and the heat exchanger 52, or a combination thereof, and controls the amount of steam generated by the steam supply unit 4 or the amount of steam supplied from the steam supply unit 4 to be below the target supply amount (S133).

[0185] Specifically, when the target supply amount is exceeded, the output of the pump 51 is suppressed to prevent the pump 51 from operating excessively, thereby reducing unnecessary energy costs. Here, as one example, the pump 51 is connected to an inverter, and the inverter changes the rotation speed of a motor mounted on the pump 51, thereby controlling the output. As another example, the pump 51 is configured with multiple pumps connected in series, and the output is controlled by adjusting the number of pumps driven by a control signal. As yet another example, the pump 51 is configured with multiple pumps connected in series or in parallel with different outputs, and the output is controlled by adjusting the pumps driven and the number of pumps driven by a control signal.

[0186] Furthermore, if the target supply amount is exceeded, the openings of valves V2 and V3 are adjusted to prevent excessive load from being placed on other components of the gas recovery device 1. For example, by reducing the opening of valve V2 or valve V3, the amount of steam supplied can be reduced, thereby reducing the amount of energy required for steam generation, steam removal, or steam compression. Note that the openings of valves V2 and V3 are, for example, controlled by adjusting the position and orientation of the internal flow control valves in response to a control signal from processor 82.

[0187] Furthermore, if the target supply amount is exceeded, the amount of heat or cold energy added in the heat exchanger 52 is adjusted, or the output of the pump 42 is adjusted, thereby reducing the operating rate of the heat exchanger 52 and the pump 42 and reducing excess energy loss. The heat exchanger 52 is controlled by reducing the amount of energy added for heating or cooling and operating at a slower heating or cooling rate. The pump 42 is controlled in the same manner as the pump 51.

[0188] Here, the processor 82 only determines whether the target supply amount (upper limit) of the supply gas has been exceeded, but it is also possible to further determine whether the target supply amount (lower limit) of the supply gas has been exceeded, and to control the amount of supply gas to increase if it has been exceeded. If the supply amount of supply gas falls below the target supply amount (lower limit), the amount of carbon dioxide recovered will decrease. As a result, the carbon dioxide recovery efficiency will decrease. Therefore, by adjusting the supply amount of supply gas to an appropriate amount, it is possible to optimize the energy cost.

[0189] Next, the processor 82 obtains the time since the control signal of S119 was generated from a timer (not shown) mounted on the processing device 8, and determines whether the obtained time has reached the release completion time (S134). If the release completion time has not been reached, the processor 82 continues monitoring in S131.

[0190] When it is determined that the release completion time has been reached, the processor 82 generates a control signal indicating the completion of the series of processes and transmits the control signal to each valve that is in an open state and each pump that is in an operating state, which causes each valve to close and each pump to stop operating, thereby terminating the operation of the gas recovery device 1.

[0191] 3A and 3B, the storage tank 54 can be filled with carbon dioxide at a higher concentration. That is, carbon dioxide at a higher concentration can be recovered downstream from the valve V53.

[0192] In this embodiment, the gas recovery device 1 has been described on the assumption that it is composed of a supply gas supply unit 9, a humidity adjustment unit 2, a carbon dioxide separation unit 3, a steam supply unit 4, a carbon dioxide recovery unit 5, a residual gas discharge unit 6, a stagnant gas recovery unit 7, and a processing device 8. However, an apparatus for recovering carbon dioxide may be composed of the supply gas supply unit 9, the carbon dioxide separation unit 3, the steam supply unit 4, the carbon dioxide recovery unit 5, and the processing device 8, and the humidity adjustment unit 2, the residual gas discharge unit 6, and the stagnant gas recovery unit 7 may be auxiliary functional units that can be added as desired.

[0193] 3. Configuration of the Heat or Cold Heat Supplier FIGS. 7A to 7C are diagrams illustrating a schematic configuration of a heat or cold heat supplier in a gas recovery apparatus 1 according to an embodiment of the present disclosure. According to the heat or cold heat supplier illustrated in FIG. 7A, the heat or cold heat supplier includes a cooling unit 90, a heating unit 95, a conduit 91 configured to circulate through the cooling unit 90 and the heating unit 95, and a heat medium or refrigerant 92 filled in the conduit 91. Hereinafter, the heat medium or refrigerant 92 may be simply referred to as the "heat medium 92," "heat medium," "refrigerant 92," or "refrigerant" depending on the circumstances. Cooling and heating can be efficiently performed by utilizing the gas-liquid phase transition of the refrigerant or heat medium. Furthermore, by providing a pump for pressurizing the refrigerant or heat medium and a valve for depressurizing the refrigerant or heat medium, the temperature of the pressurized region can be further increased, thereby enabling effective heating. Furthermore, the temperature of the depressurized region decreases, enabling effective cooling. An example of such a heat or cold heat supplier is a heat pump such as a heat exchanger. The cooling unit 90 has a cold source adjacent to the conduit 91. The cold heat source can be derived from outside or inside the gas recovery device 1. Examples of such cold heat sources include external sources such as naturally occurring cold heat, cold heat from a phase transition or expansion of a gas or liquid (water or liquefied natural gas is an example of a liquid), cold heat as sensible heat possessed by a gas or liquid, cold heat due to an endothermic reaction, cold heat due to the Peltier effect or the Joule-Thomson effect, and combinations thereof, as well as internal sources such as steam generated in the steam supply unit 4.

[0194] The heating unit 95 has a heat source adjacent to the pipeline 91. The heat source can be derived from either an external source or an internal source of the gas recovery apparatus 1. Examples of such heat sources include external sources such as heat from a power generation facility, heat from a factory facility or an electrical facility, heat from a phase transition or compression of a gas or liquid (for example, water or liquefied natural gas), sensible heat of a gas or liquid, naturally occurring heat and heat due to the Peltier effect, and combinations thereof, as well as internal sources such as the residual gas discharge unit 6 or the residual gas discharged by the residual gas discharge unit 6. In this specification, the expression "naturally occurring" heat or cold includes, but is not limited to, heat or cold derived from seawater, lake water, river water, stored water, the atmosphere, solar heat, etc.

[0195] The pipe 91 has a cavity therein, which is filled with a heat transfer medium or refrigerant 92. The heat transfer medium or refrigerant 92 is an intermediate substance that transfers heat or cold, and serves as a heat transfer medium when transferring heat, and as a refrigerant when transferring cold. Therefore, the heat transfer medium and the refrigerant may be made of the same substance. Various substances can be used as the heat transfer medium or refrigerant 92, such as water, oil, air, steam, sand, organic compounds, gas, liquefied nitrogen, and brine.

[0196] 7A supplies cold to at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61 of the gas recovery device 1, the cooling unit 90 is installed outside or inside the gas recovery device 1, and the heating unit 95 is installed in at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61. As a result, cold is supplied to at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61 via the refrigerant cooled by the cooling unit 90. When cold is supplied to at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61, the refrigerant warmed in at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61 returns to the cooling unit 90 again through the pipe 91. Then, cold is again supplied to at least one of the heat exchanger 21, the heat exchanger 52, and the heat exchanger 61 via the refrigerant cooled by the cooling unit 90.

[0197] 7A supplies heat to at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61 of the gas recovery device 1, the heating unit 95 is installed outside or inside the gas recovery device 1, and the cooling unit 90 is installed in at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61. As a result, heat is supplied to at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61 via the heat medium heated by the heating unit 95. When heat is supplied to at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61, the heat medium cooled in at least one of the heat exchanger 21, the steam generator 41, the heat exchanger 52, and the heat exchanger 61 returns to the heating unit 95 again through the pipe 91. Then, heat is supplied again to at least one of the heat exchanger 21 , the steam generator 41 , the heat exchanger 52 and the heat exchanger 61 via the heat medium heated by the heating unit 95 .

[0198] In this way, the heat or cold supply device has a pipe 91 that forms a circulation path between the cooling section 90 and the heating section 95, and by filling the inside of the pipe 91 with a heat transfer medium or refrigerant 92, it is possible to circulate the heat transfer medium or refrigerant.

[0199] FIG. 7B shows a more specific example of a heat or cold supply. As described above, the heat source of the heat or cold supply can be derived from the gas recovery device 1. Cooling and heating can be performed efficiently by utilizing the gas-liquid phase transition of the refrigerant or heat medium. Furthermore, by providing a pump for pressurizing the refrigerant or heat medium and a valve for depressurizing the refrigerant or heat medium, the temperature in the pressurized region can be further increased, allowing for effective heating. Furthermore, the temperature in the depressurized region decreases, allowing for effective cooling. As described in FIG. 4 , the supply gas from which carbon dioxide has been separated is introduced as residual gas into the residual gas discharge section 6. Because this residual gas is typically heated to a high temperature, it is cooled by the heat exchanger 61 to a temperature that allows it to be discharged to the outside. Therefore, FIG. 7B shows a case in which the uncooled residual gas is supplied as the heat medium. In this case, cooling of the residual gas is not required, and therefore the heat exchanger 61 does not need to be installed.

[0200] 7B , when the supply gas from which carbon dioxide has been separated is introduced as residual gas into the residual gas discharge section 6 via pipe P61, the residual gas is supplied as is as a heat medium to at least one of the heat exchanger 21, the steam generator 41, and the heat exchanger 52. The residual gas supplied to at least one of the heat exchanger 21, the steam generator 41, and the heat exchanger 52 is cooled by heat exchange in at least one of the heat exchanger 21, the steam generator 41, and the heat exchanger 52, and then released to the outside from at least one of the heat exchanger 21 and the heat exchanger 52 (although not shown, it is also possible to configure the residual gas to be released to the outside after heat exchange in the steam generator 41). This allows the heat generated inside the gas recovery device 1 to be effectively reused, and eliminates the need to install a heat exchanger 61 or the like for cooling the residual gas, thereby simplifying the configuration of the gas recovery device 1.

[0201] Figure 7C shows another more specific example of the heat or cold supplier. As described above, the heat source or cold source of the heat or cold supplier can be derived from within the gas recovery device 1. As described in Figures 5 and 6, the carbon dioxide recovery unit 5 is provided with a heat exchanger 52 for cooling the retained gas to 24°C (room temperature). Furthermore, the steam supply unit 4 is provided with a steam generator 41 for heating supply water to generate steam. Therefore, Figure 7C shows a case in which the steam generator 41 is used as the cooling unit 90 and the heat exchanger 52 is used as the heating unit 95.

[0202] 7C , the heat or cold supply device includes a cooling unit 90, a heating unit 95, a pipe 91 configured to circulate through the cooling unit 90 and the heating unit 95, and a heat medium or refrigerant 92 filled inside the pipe 91. The cooling unit 90 has a steam generator 41 as a cold heat source adjacent to the pipe 91. The steam generator 41 heats supplied water to generate steam from the supplied water. By utilizing heat supplied via a heat medium 92 filled in the pipe 91 as a heat source, the heat medium 92 is cooled by the supply water. The heating unit 95 also has a heat exchanger 52 as a heat source adjacent to the pipe 91. The heat exchanger 52 cools the stagnant gas to 24°C (room temperature), a temperature at which the stagnant gas can be discharged. By utilizing the cold supplied via the refrigerant 92 filled in the pipe 91 as a cold heat source, the refrigerant 92 is heated by the stagnant gas.

[0203] 7C , cold energy is supplied to the heat exchanger 52 via the filled refrigerant 92 using the supply water of the steam generator 41 as a cold energy source. The cold energy supplied to the heat exchanger 52 is used to cool the retained gas, while the retained gas in the heat exchanger 52 is used as a heat source to heat the filled refrigerant 92, which is then supplied as a heat medium 92 to the steam generator 41. The heat supplied to the steam generator 41 is used to heat the supply water, while the supply water of the steam generator 41 is used as a cold energy source to cool the filled heat medium 92, which is then used as the refrigerant 92 to supply cold energy to the heat exchanger 52 again. In this way, it is possible to form a circulation system that effectively utilizes the heat or cold energy generated in the steam generator 41 and the heat exchanger 52.

[0204] Although Figure 7C describes the case where a circulation system is formed between the steam generator 41 and the heat exchanger 52, a circulation system can be formed in a similar manner between any configurations that allow a combination of heating and cooling, such as the heat exchanger 21 and the heat exchanger 52, the steam generator 41 and the heat exchanger 61, or the heat exchanger 21 and the heat exchanger 61.

[0205] 4. Configuration of Other Gas Recovery Apparatus According to the Present Disclosure In the gas recovery apparatus 1, the carbon dioxide separation section 3 uses the carbon dioxide separation material 33 made of a solid absorbent as a carbon dioxide separator. However, a structure using a carbon dioxide separation membrane that selectively permeates carbon dioxide in addition to the solid absorbent may also be adopted. Below, a gas recovery apparatus using such a carbon dioxide separation membrane will be described as one embodiment. Here, FIG. 8 is a diagram showing a schematic configuration of a gas recovery apparatus 501 according to one embodiment of the present disclosure. Note that, since the gas recovery apparatus 501 of this embodiment has a structure in which a carbon dioxide separation membrane is used for the gas recovery apparatus 1, the same components and members as those of the gas recovery apparatus 1 are designated by the same reference numerals or the reference numerals are omitted, and their description will also be omitted.

[0206] As shown in FIG. 8 , the gas recovery apparatus 501 is broadly composed of a feed gas supply unit 9, a humidity adjustment unit 2, a carbon dioxide separation unit 30, a steam supply unit 40, a carbon dioxide recovery unit 50, a residual gas discharge unit 6, and a treatment device 8. That is, compared to the gas recovery apparatus 1, the gas recovery apparatus 501 does not have a stagnant gas recovery unit 7. Also, while the gas recovery apparatus 1 has valves between each unit, the gas recovery apparatus 501 does not have valves. That is, the gas recovery apparatus 501 does not perform a process in which the sorption process and the release process are alternately repeated as in the gas recovery apparatus 1, but instead performs a process in which carbon dioxide is separated and recovered from the feed gas continuously. In particular, in the gas recovery apparatus 501, a feed gas containing carbon dioxide is supplied to the carbon dioxide separation unit 30 via the humidity adjustment unit 2, and the carbon dioxide selectively permeates the membrane. Meanwhile, steam is supplied to the carbon dioxide separation unit 30, causing a decrease in the partial pressure of the permeated carbon dioxide. Then, by utilizing the partial pressure difference resulting from the decrease in partial pressure, carbon dioxide is further separated from the supply gas, and the carbon dioxide is concentrated and recovered in the carbon dioxide recovery section 50.

[0207] As a more specific connection configuration, as shown in FIG. 8 , the gas recovery apparatus 1 includes a supply gas supply unit 9 to which a supply gas is supplied from one end (upstream side) thereof via an inlet pipe P11. The humidity adjustment unit 2 is connected to the other end (downstream side) of the supply gas supply unit 9. One end (downstream side) of the humidity adjustment unit 2 is connected to one end (upstream side) of the carbon dioxide separation unit 30 via a pipe P25. Furthermore, one end (downstream side) of the steam supply unit 40 is connected to one end (upstream side) of the carbon dioxide separation unit 30 via a pipe P42. More specifically, the pipe P25 is connected to a first internal space 32a side of the carbon dioxide separation unit 30, which will be described later, and the pipe P42 is connected to a second internal space 32b side of the carbon dioxide separation unit 30, which will be described later. In other words, compared to the gas recovery apparatus 1, the humidity adjustment unit 2 and the steam supply unit 40 are independently connected to different positions of the carbon dioxide separation unit 30 via separate pipes.

[0208] 8, the other end (downstream side) of the carbon dioxide separation unit 30 is connected to one end (upstream side) of the carbon dioxide capture unit 50 via a pipe P51, and is also connected to one end (upstream side) of the residual gas discharge unit 6 via a pipe P61. More specifically, the pipe P61 is connected to a first internal space 32a side of the carbon dioxide separation unit 30, which will be described later, and the pipe P51 is connected to a second internal space 32b side of the carbon dioxide separation unit 30, which will be described later. In other words, compared to the gas recovery device 1, the carbon dioxide separation unit 30 is independently connected to the carbon dioxide capture unit 50 and the residual gas discharge unit 6 via separate pipes.

[0209] Furthermore, as shown in FIG. 8 , a processing device 8 is electrically connected to each component, and sends control signals to the supply gas supply unit 9, humidity adjustment unit 2, carbon dioxide separation unit 30, steam supply unit 40, carbon dioxide recovery unit 50, and residual gas discharge unit 6 to control the operation of each component.

[0210] (Carbon dioxide separation unit 30) The carbon dioxide separation unit 30 is a modularized device composed of, for example, a substantially cylindrical housing 31 and a carbon dioxide separation membrane 34 disposed in an internal space 32 of the housing 31. That is, in the carbon dioxide separation unit 30, the carbon dioxide separation membrane 34 is used as a carbon dioxide separator. The internal space 32 of the housing 31 is divided into two internal spaces (a first internal space 32a and a second internal space 32b) by the carbon dioxide separation membrane 34. Alternatively, the carbon dioxide separation membranes 34 may be stacked as flat membranes so that the internal space 32 of the housing 31 alternates between spaces through which the supply gas flows and spaces through which reduced-pressure steam flows. Here, the carbon dioxide separation membrane 34 is fixed to the inner wall of the housing 31 by a retaining member such as an O-ring, but the fixing method is not limited to this and may also be a fixing method using an adhesive or other mechanical fixing method.

[0211] The carbon dioxide separation membrane 34 comprises a film that selectively transmits carbon dioxide on the surface of a porous body, and has a structure in which, for example, gelling polymer particles, which will be described later, are applied. That is, in the carbon dioxide separation membrane 34, the pores on two opposing surfaces of the porous body are blocked with the gelling polymer particles. In other words, the carbon dioxide separation membrane 34 has a three-layer structure in which gelling polymer particles, a porous body, and gelling polymer particles are layered in this order. The porous body and gelling polymer particles that make up the carbon dioxide separation membrane 34 are described below.

[0212] The porous body constituting the carbon dioxide separation membrane 34 is a solid having many fine pores inside, at least some of which open to the surface of the carbon dioxide separation membrane 34. Of the pores in the porous body, those that open to the surface of the carbon dioxide separation membrane 34 are called "surface pores," and the inner diameter of the opening of the surface pores on the surface of the carbon dioxide separation membrane 34 is called the "pore diameter." It is desirable that the surface pores on one side form pores as continuous as possible with the internal pores and the surface pores on the other side, allowing carbon dioxide to pass through freely.

[0213] The material of the porous body is not particularly limited, but is preferably a resin. Specific examples include polyethersulfone (PES), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), cellulose mixed ester or nitrocellulose (NC), polyolefin, polyethylene, polypropylene, polymethylpentene, polyketone, polyimide, polystyrene, polymethyl methacrylate, polydimethylsiloxane, polyester, nylon, etc. These materials have excellent mechanical strength and heat resistance and can be preferably used as the porous body.

[0214] The porous body preferably has hydrophilic groups such as OH groups or COOH groups on its surface. This improves the contact between the gelling polymer particles (described later) and the porous body, allowing a film containing the gelling polymer particles to be uniformly formed on the surface of the porous body. These hydrophilic groups need only be present on at least the surface of the porous body that supports the gelling polymer particles (the area where the gelling polymer particles block the surface pores of the porous body). They may be present on the entire surface of the porous body or only on the surface that supports the gelling polymer particles. These hydrophilic groups may be introduced into the porous body by using a resin containing hydrophilic groups as a material, or by subjecting the porous body to a hydrophilization treatment. Examples of hydrophilization treatments include plasma treatment, ozone treatment, treatment with a strong acid, treatment with a strong base, and treatment with an oxidizing agent.

[0215] An intermediate layer may be provided on the surface of the porous body. This allows the gelling polymer particles to be stably fixed on the porous body. Polydimethylsiloxane, porous silica microparticles, fumed silica, and zeolite microparticles can be preferably used as the material for the intermediate layer. These materials not only function to fix the gelling polymer particles to the surface of the porous body, but also have relatively excellent carbon dioxide permeability, so they can function to fix the particles without impairing the permeability or selective permeability of the carbon dioxide separation membrane 34. Furthermore, the surface area of ​​the single-phase membrane can be increased by providing an uneven surface in the intermediate layer and then applying the gelling polymer particles thereon.

[0216] The pore size of the surface pores of the porous body is preferably less than 2 μm, more preferably less than 0.5 μm, even more preferably less than 0.22 μm, and even more preferably less than 0.15 μm. The pore size of the surface pores of the porous carrier is preferably 0.01 μm or more. The maximum pore size of the porous carrier is preferably less than 3 μm. The "pore size of the surface pores" is the pore size measured as the largest particle size that can pass through the entire support membrane, and the "maximum pore size" may be the maximum value of the pore size measured by a scanning electron microscope. The number of pores on the surface of the porous body and the area occupied by the pores per surface area of ​​the membrane are preferably large. The pores in the porous body are preferably as continuous as possible, and the maximum volume is preferably large. This can improve the carbon dioxide permeation flux.

[0217] The outer shape of the porous body is preferably plate-like or cylindrical, and it is also preferable that it has a first surface and a second surface that are approximately parallel to each other, and it is more preferable that the surface pores of the first surface are blocked with gelling polymer particles and the surface pores of the second surface are not blocked with gelling polymer particles. The dimensions of the porous body can be selected appropriately depending on the application, and may be selected, for example, depending on the amount of feed gas to be treated.

[0218] The carbon dioxide separation membrane 34 contains gelling polymer particles having at least one of basic functional groups or acidic functional groups and has a thickness of less than 5 μm. Due to this configuration, the carbon dioxide separation membrane 34 can selectively permeate carbon dioxide at a large permeation flux. In this embodiment, the carbon dioxide separation membrane 34 is assumed to be a membrane containing gelling polymer particles having at least one of basic functional groups or acidic functional groups and consisting of three layers, but is not limited to this. For example, a multilayer membrane with three or more layers may be used, which is formed by repeatedly applying and drying a suspension containing gelling polymer particles, followed by applying and drying a suspension containing gelling polymer particles.

[0219] The carbon dioxide separation membrane 34 may contain only one type of gelling polymer particles or two or more types of gelling polymer particles. When the carbon dioxide separation membrane 34 contains two or more types of gelling polymer particles, it is preferable that one type of gelling polymer particles has a basic functional group and the other type of gelling polymer particles has an acidic functional group.

[0220] The gelling polymer particles have at least one of a basic functional group and an acidic functional group. Typical gelling polymer particles are polymer compound particles that have an amino group, an ammonium group, or an imidazolium group and have gelling properties, and it is particularly desirable that the particles have an amino group.

[0221] The polymer compound particles having an amino group are particles made of a polymer compound having an amino group, and are preferably composed only of a polymer compound having an amino group, but may also contain materials used in preparing the particles, such as particle size adjusting components such as surfactants, polymers of (meth)acrylamide derivatives, crosslinking agents, unreacted monomers, etc.

[0222] The polymer compound having an amino group is not particularly limited, and examples thereof include (meth)acrylamide polymers and derivatives thereof, polyethyleneimine and derivatives thereof, polyvinylamine and derivatives thereof, polyvinyl alcohol and derivatives thereof, and polyallylamine and derivatives thereof. It may be polystyrene into which an amino group has been introduced, or a polysaccharide such as cellulose or dextrin into which an amino group has been introduced. Specific constituent monomers include N,N-dimethylaminopropyl methacrylamide, N,N-diethylaminopropyl methacrylamide, N,N-dimethylaminoethyl methacrylamide, N,N-diethylaminoethyl methacrylamide, N,N-dimethylaminopropyl methacrylate, N,N-diethylaminopropyl methacrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminopropyl acrylamide, N,N-diethylaminopropyl acrylamide, N,N-dimethylaminoethyl acrylamide, N,N-diethylaminoethyl acrylamide, and 3-aminopropyl methacrylamide hydrochloride. , 3-aminopropylacrylamide hydrochloride, N,N-dimethylaminopropyl acrylate, N,N-diethylaminopropyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, 3-aminopropyl methacrylate hydrochloride, 3-aminopropyl acrylate hydrochloride, N-(2,2,6,6-tetramethylpiperidin-4-yl)methacrylamide, N-(2,2,6,6-tetramethylpiperidin-4-yl)acrylamide, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl acrylate, and the like can be mentioned, and an acrylamide polymer is preferable.

[0223] The amino group of a polymer compound having an amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group, but it is preferable that the acid dissociation constant of the conjugate acid is designed. In particular, in order to dissolve carbon dioxide, it is preferable that the acid dissociation constant of the amino group is equal to or greater than the acid dissociation constant of carbonic acid. Among these, a secondary amino group or a tertiary amino group is preferable, and a tertiary amino group is more preferable. A dialkylamino group such as a dimethylamino group is even more preferable. Furthermore, the amino group of the polymer compound may be bonded to either the main chain or the side chain, but is preferably bonded to the side chain.

[0224] The polymer compound having an amino group preferably has a hydrophobic group. The hydrophobic group to be introduced into the polymer compound is preferably C Ｘ H ２Ｘ Or C Ｘ H ２Ｘ＋１ Examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, an isopentyl group, a hexyl group, a cyclohexyl group, and the like. Of these, an isobutyl group and a tert-butyl group are more preferable. Alternatively, the hydrophobic group may be a group in which a hydroxyl group is bonded to the above hydrophobic group, such as a hydroxyethyl group, a hydroxypropyl group, or a hydroxybutyl group. The polymer compound having an amino group preferably has a polymer density within the particles in a dispersed state after the polymer compound particles are swelled in water of 0.3 to 80%, and more preferably 1 to 60%.

[0225] Amino group-containing polymer compound particles can be prepared using a solution containing monomer components (hereinafter referred to as a "particle preparation solution"). In this specification, "monomer components" refers to all monomers used in the synthesis of the polymers of the amino group-containing polymer compound particles. The method for producing the polymer compound particles is not particularly limited, and conventionally known methods such as precipitation polymerization, pseudo-precipitation polymerization, emulsion polymerization, dispersion polymerization, suspension polymerization, and seed polymerization can be used.

[0226] The monomer components used to prepare the particles preferably contain at least a monomer having an amino group, and also contain a monomer having an amino group and a monomer not having an amino group. That is, the polymer compound having an amino group may be a homopolymer or copolymer of a monomer having an amino group, or may be a copolymer of a monomer having an amino group and a monomer not having an amino group. By controlling the ratio of these monomers, the density of the amino groups in the polymer compound particles can be adjusted to an appropriate range. The monomer having an amino group and the monomer not having an amino group, which are used as needed, are preferably substituted (meth)acrylamide monomers, more preferably substituted acrylamide monomers.

[0227] For the description and preferred range of the amino group of the monomer having an amino group, reference can be made to the description and preferred range of the amino group of the polymer compound having an amino group. The number of amino groups possessed by the monomer is not particularly limited and may be one or two or more. When the monomer has two or more amino groups, the amino groups may be the same or different. The monomer having an amino group is not particularly limited, but examples thereof include N-(aminoalkyl)acrylamide and N-(aminoalkyl)methacrylamide, with N-(aminoalkyl)acrylamide being preferred.

[0228] The monomer component preferably contains a monomer having a hydrophobic group together with a monomer having an amino group. The description and preferred range of the hydrophobic group of the monomer having a hydrophobic group can be found in the description and preferred range of the hydrophobic group that can be employed in the polymer compound having an amino group. The hydrophobic group is preferably present in a side chain. The monomer having a hydrophobic group may or may not further have an amino group.

[0229] The monomer having a hydrophobic group is not particularly limited, but examples thereof include N-alkylacrylamide, N-alkylmethacrylamide, N-alkylacrylate, N-alkylmethacrylate, N,N-dialkylacrylamide, N-(hydroxyalkyl)methacrylamide, N,N-dialkylacrylate, N-(hydroxyalkyl)methacrylate, N,N-dialkylmethacrylamide, N-(hydroxyalkyl)acrylamide, N,N-dialkylmethacrylate, and N-(hydroxyalkyl)acrylate, with N-alkylacrylamide being preferred. A preferred combination of a monomer having an amino group and a monomer having a hydrophobic group is a combination of N-(aminoalkyl)(meth)acrylamide and N-alkyl(meth)acrylamide, with N-(aminoalkyl)methacrylamide and N-alkylacrylamide being preferred. Particles composed of a copolymer of N-(aminoalkyl)(meth)acrylamide and N-alkyl(meth)acrylamide have a well-balanced and uniform distribution of hydrophobic alkyl groups and hydrogen-bonding amides within the molecule.

[0230] The proportion of the amino group-containing monomer in the monomer components is preferably 1 to 95 mol%, more preferably 5 to 95 mol%, and even more preferably 30 to 60 mol%, based on the total number of moles of the monomer components. Furthermore, when the monomer components contain a monomer having a hydrophobic group, the molar ratio of the amino group-containing monomer to the hydrophobic group-containing monomer is preferably 95:5 to 5:95, and more preferably 2:1 to 1:2. Note that a monomer having both an amino group and a hydrophobic group is classified as a monomer having an amino group.

[0231] The particle preparation solution may contain only the monomer component, or it may contain other components. Examples of other components include surfactants, crosslinking agents, polymerization initiators, and pKa adjusters. The particle size of the resulting polymer compound particles can be controlled by adjusting the type and concentration of the surfactant added to the particle preparation solution. Furthermore, the use of a crosslinking agent can control the swelling of the particles by forming a crosslinked structure in the polymer compound within the particles, thereby preventing excessive swelling. Furthermore, when a relatively large amount of crosslinking agent is used or when the monomer concentration during polymerization is set relatively high, crosslinked structures can also be formed between particles. This allows for the formation of a relatively large continuous void structure between the composite particles connected by the crosslinked structure. The pKa adjuster is used to adjust the pKa of the resulting polymer compound particles to a desired value, thereby controlling the type of gas or liquid selectively permeating the carbon dioxide separation membrane 34, the permeation flux, and the selectivity for other mixed components. Examples of surfactants that can be used include cationic surfactants such as cetyltrimethylammonium bromide. The crosslinking agent may be any agent capable of forming a crosslinked structure between the monomers used, and N,N'-alkylenebisacrylamide is preferably used. The number of carbon atoms in the alkylene group of N,N'-alkylenebisacrylamide is not particularly limited, but is preferably 1 to 12, more preferably 1 to 4, and even more preferably 1 to 2. Instead of the alkylene group, oligoethyleneimine or oligoethylene glycol may be used as a crosslinking agent that functions as a crosslinking agent chain.

[0232] As the pKa adjuster, those capable of protonating or deprotonating the amino group of the monomer can be used, and an acid such as hydrochloric acid or a base such as sodium hydroxide can be used by adjusting the concentration appropriately according to the desired pKa. In addition, since the PKa of the polymer compound particles can also be controlled by the crosslinking rate of the crosslinking agent, the above-mentioned crosslinking agent can also be used as the PKa adjuster.

[0233] The solvent for the particle preparation solution is not particularly limited, but examples include polar solvents such as water, methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, and a mixed solvent combining two or more of these polar solvents is also acceptable. Among these, water or a mixed solvent combining water with another polar solvent is preferred. The polymer compound particles having amino groups may be gel particles swollen with a liquid or may be dry particles (solid particles). In gel particles, carbon dioxide dissolves more efficiently in the liquid contained in the gel particles, allowing the amino groups inside the gel particles to efficiently contribute to carbon dioxide absorption.

[0234] The gelling polymer particles used in this embodiment may be gelling polymer particles having a basic functional group such as an amino group, gelling polymer particles having an acidic functional group, or gelling polymer particles having both a basic functional group and an acidic functional group. Examples of acidic functional groups include carboxyl groups and sulfate groups, with carboxyl groups being preferred. Examples of polymer compounds having carboxyl groups include polymer compounds containing acrylic acid or methacrylic acid as constituent monomers. The gelling polymer particles having acidic functional groups are preferably composed solely of polymer compounds having acidic functional groups, but may also contain other components.

[0235] The gelling polymer compound particles (gelling polymer particles) used in this embodiment preferably have a particle size in a dry state of 5 nm to 10 μm, more preferably 5 nm to 500 nm. The hydrodynamic particle size of the polymer compound particles after swelling in water is preferably 10 nm to several tens of μm, more preferably 10 nm to 50 μm, even more preferably 20 nm to 2 μm, and even more preferably 90 nm to 1 μm, as measured by dynamic light scattering. The "particle size after swelling in water" of the polymer compound particles refers to the particle size of dried polymer compound particles after immersion in water at 30° C. for 24 hours, and is the average particle size measured by dynamic light scattering.

[0236] The liquid contained in the gel particles is not particularly limited, but examples thereof include polar solvents such as water, methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, and may also be mixed solvents combining two or more of these polar solvents. Among these, it is preferable to use water or a mixed solvent of water and another polar solvent. That is, it is preferable that the gel particles are hydrogel particles. The water content in the gel particles is preferably 0.05 mL or more, and more preferably 0.5 mL or more, per 1 g of solid content. Furthermore, the water content in the gel particles is preferably 20 mL or less, and more preferably 10 mL or less.

[0237] The carbon dioxide separation membrane 34 containing gelling polymer particles having at least one of basic functional groups or acidic functional groups may contain polymer compounds or additives within the gelling polymer particles or in regions outside the gelling polymer particles in the membrane. The polymer compounds other than the gelling polymer are not particularly limited, but are preferably polymer compounds that respond to stimuli such as temperature changes. Examples of responses to stimuli include changes in the acid dissociation constant of the functional group, changes in three-dimensional structure, changes in swelling, changes in hydrophilicity, changes in water content, changes in water absorbency, changes in the amount of bicarbonate ions dissolved, and changes in the amount of hydrogen sulfide ions dissolved. Alternatively, it is preferable to have an amine whose conjugate acid has a designed acid dissociation constant. In particular, to dissolve carbon dioxide, it is preferable that the acid dissociation constant of the amino group is equal to or greater than the acid dissociation constant of carbonic acid. Among these, secondary or tertiary amino groups are preferred, with tertiary amino groups being even more preferred. Dialkylamino groups such as dimethylamino groups are even more preferred. Furthermore, the amino groups of the polymer compounds may be attached to the main chain or side chain, but are preferably attached to the side chain. Examples of the additives include membrane stabilizers, absorption promoters, diffusion promoters, moisture absorbents, antioxidants, and the like.

[0238] Examples of the film stabilizer include polymer compounds, polymerizable molecules (polymerizable compounds), crosslinking agents such as titanium crosslinking agents, primary amines, secondary amines, tertiary amines, etc. Among these, preferred polymer compounds include polymer compounds having a primary amino group such as polyvinylamine, polymer compounds having a secondary amino group, polymer compounds having a tertiary amino group, compounds having a quaternary ammonium group, polymer compounds having multiple types of primary amino group, secondary amino group, tertiary amino group, and quaternary ammonium group, polyvinyl alcohol, polyethylene, polyvinyl alcohol / polyethylene copolymer, etc.

[0239] Furthermore, when a polymerizable molecule is used as the membrane stabilizer, the polymer compound produced by the polymerization reaction of this molecule within the membrane also functions as a membrane stabilizer. This makes it easier to maintain a uniform membrane shape without excessive swelling, even after the addition of water or after gas absorption and dissipation following membrane formation. Examples of polymerizable molecules include monomers having a polymerizable group, such as (meth)acrylic monomers. Among these, (meth)acrylamide or (meth)acrylamide derivatives are preferably used. Examples include alkylacrylamides, substituted or unsubstituted aminoalkyl(meth)acrylamides, and acrylamide derivatives having two polymerizable groups. Among these, substituted aminoalkylacrylamides and acrylamide derivatives having two polymerizable groups are preferably used. Substituted aminoalkylacrylamides and acrylamide derivatives having two polymerizable groups are preferably used in combination, with the molar fraction preferably being 60-99:40-1, more preferably 80-99:20-1, and even more preferably 90-99:10-1. Specific examples of monomers having a polymerizable group include N-isopropylacrylamide (NIPAM), tert-butylacrylamide (TBAM), N,N-dimethylaminopropylmethacrylamide (DMAPM), N,N'-methylenebisacrylamide (BIS), acrylamide, etc. These polymerizable compounds may be used alone or in combination of two or more. When two or more are used in combination, a preferred example is a combination of N,N-dimethylaminopropylmethacrylamide (DMAPM) and N,N'-methylenebisacrylamide (BIS). The content of the membrane stabilizer in the carbon dioxide separation membrane 34 is preferably 1 to 89 mass% based on the total mass of the membrane.

[0240] The absorption promoter is a compound that functions to promote the absorption of acidic gases into the carbon dioxide separation membrane 34. The diffusion promoter is a compound that functions to promote the diffusion of acidic gases from the gelling polymer particles. In this embodiment, an absorption / diffusion promoter that functions as both an absorption promoter and a diffusion promoter may be used. These absorption promoters, diffusion promoters, and absorption / diffusion promoters may also function as membrane stabilizers. The total content of the absorption promoter, diffusion promoter, and absorption / diffusion promoter in the carbon dioxide separation membrane 34 is preferably 0.05 mL or more, and more preferably 0.1 mL or more, per 1 g of solids. The water content in the gel particles is preferably 20 mL or less, and more preferably 10 mL or less. The content of the absorption promoter in the carbon dioxide separation membrane 34 is preferably 0.1 to 12 N, more preferably 1 to 10 N, and even more preferably 3 to 9 N, in terms of amine concentration.

[0241] Low molecular weight amines can be preferably used as the absorption promoter, diffusion promoter, and absorption / diffusion promoter. The molecular weight of the low molecular weight amine is preferably 61 to 10,000, more preferably 75 to 1,000, and even more preferably 90 to 500. The boiling point of the low molecular weight amine is preferably 80°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher, because it can be used for a long period of time and is practical. To raise the boiling point, an amine-containing compound that has a moiety that forms a salt with a counter ion, like an ionic liquid, and is liquid may also be used.

[0242] The low-molecular-weight amine may contain any of a primary amino group, a secondary amino group, a tertiary amino group, an ammonium group, and an imidazolium group. The low-molecular-weight amine may contain multiple amino groups, ammonium groups, and imidazolium groups, preferably 1 to 3. The secondary amino group or tertiary amino group may be a cyclic amino group. Furthermore, the low-molecular-weight amine may contain a functional group other than an amino group, an ammonium group, or an imidazolium group, such as a hydroxyl group. The low-molecular-weight amine preferably contains 0 to 2 hydroxyl groups. Examples of preferred low-molecular-weight amines include amines having an amino group and a hydroxyl group, and amines having three amino groups. Examples of more preferred low-molecular-weight amines include amines having a secondary amino group and a hydroxyl group. Amines having a boiling point of 150°C or higher and a hydroxyl group are particularly preferred because they can dramatically increase the amount of acidic gas emitted, particularly in high-concentration regions, and are suitable for repeated use.

[0243] Examples of low molecular weight amines include ETA (Ethanol Amine), DMAE (2-(Dimethylamino)ethanol), and IPAE (Isopropylamino) DMAEA (2-(Dimethylamino)ethylamine), TMEDA (Tetrameth T MHAD (N,N,N',N'-Tetramethyl-1,6-hexanediamine), DEOA (Diethanol amine), MDEOA (N-Methyldiethanolamine), DAMDPA (Diamino-N-methyl dipropyl amine), 1-2HE-PRLD (1-2 Hydroxy ethylene pyrrolidine), 1-2HE-PP (1-2 Hydroxyethylepiperidine), Bis(2DMAE)ER(Bis(2-dimethylaminoethyl) ether), e(PMDETA) (Pentamethyldiethylenetriamine), AEAE (2-(2-Aminoethylamino)ethanol), TAEA (Tris(2-aminoethyl)amine), DETA (Diethylenetriamine), or TETA (Triethylenetetramine). Among these, DMAE, IPAE, Bis(2DMAE)ER, 1-2HE-PRLD, 1-2HE-PP, It is preferable to use TM-1,4-DAB, TMHAD, or PMDETA, and among these, it is more preferable to use IPAE, Bis(2DMAE)ER, 1-2HE-PP, TM-1,4-DAB, TMHAD, or PMDETA because they have a relatively high boiling point and are difficult to evaporate. It is even more preferable to use IPAE, TM-1,4-DAB, TMHAD, or PMDETA because increasing their concentration can significantly increase the amount of acidic gas emitted, and it is particularly preferable to use IPAE, TMHAD, or PMDETA because they are easily available.

[0244] The moisture absorbent that can be used as an additive is preferably one that, when made into a saturated aqueous solution, has a relative humidity of 90% or less at 25°C. Examples of such moisture absorbents include ions such as bromide ions, chloride ions, acetate ions, carbonate ions, bicarbonate ions, lithium ions, potassium ions, calcium ions, magnesium ions, and sodium ions. Examples of such moisture absorbents also include salts such as lithium bromide, lithium chloride, calcium chloride, potassium acetate, magnesium chloride, potassium carbonate, and sodium carbonate. When a moisture absorbent is added, the amount added is preferably 0.01 to 10 mass% of the total amount of the film.

[0245] Antioxidants that can be used as additives are those that can suppress or prevent oxidation by adding them. Examples of such antioxidants include vitamin C (ascorbic acid), vitamin E (tocopherol), BHT (dibutylhydroxytoluene), BHA (butylhydroxyanisole), sodium erythorbate, propyl gallate, sodium sulfite, sulfur dioxide, hydroquinone, and derivatives thereof. When an antioxidant is added, the amount added is preferably 0.01 to 10 mass% of the total amount of the film. The additives described above may be used alone or in combination of two or more types.

[0246] The carbon dioxide separation membrane 34 has a surface area of ​​1 cm ２ It is preferable that the carbon dioxide separation membrane 34 has a nitrogen permeation flux of 100 GPU or less at 40°C, and more preferably 10 GPU or less. Furthermore, it is preferable that the carbon dioxide separation membrane 34 has a carbon dioxide permeation flux of 10 GPU or more at 40°C, and more preferably 100 GPU or more. When the nitrogen permeation flux and the carbon dioxide flux are within the above ranges, carbon dioxide can be selectively permeated relative to nitrogen, and therefore carbon dioxide can be selectively separated and efficiently recovered from a feed gas or other mixed gas containing nitrogen and carbon dioxide.

[0247] The "permeation flux" is a value calculated by the following formula (1): Q = L / A × ΔP (1) In formula (1), Q represents the permeation flux, L represents the permeation flow rate per unit time, A represents the membrane area, and ΔP represents the partial pressure difference on both sides of the monolayer membrane. The permeation flow rate L can be measured by gas chromatography or the like as the amount of gas that permeates the membrane per unit time, and the unit of the permeation flux Q is GPU (1 GPU is 1.0 × 10 －６ (cm ３ (STP) / (s・cm ２ The partial pressure difference ΔP can be calculated by measuring the partial pressure of the gas on the gas supply side and the partial pressure of the gas on the permeation side using a pressure gauge and gas chromatography, etc., and calculating the difference between them. Also, "selectivity" is the permeation flux Q of the selectively permeating gas. Ｓ is used as the numerator, and the permeation flux Q of other gases ０ The ratio Q with Ｓ / Q ０ is.

[0248] (Steam supply unit 40) The steam supply unit 40 generates and supplies steam upstream of the carbon dioxide separation unit 30 in order to reduce the partial pressure of carbon dioxide in the carbon dioxide separation unit 30 and to create a partial pressure difference between the first internal space 32a side and the second internal space 32b side. Furthermore, supplying steam to the carbon dioxide separation membrane 34 in the steam supply unit 40 also has a humidifying effect that prevents performance degradation due to dryness across the entire carbon dioxide separation membrane 34. Therefore, the steam is supplied with its temperature, humidity, pressure, and the like adjusted so that the partial pressure of carbon dioxide in the second internal space 32b and the carbon dioxide separation membrane 34 can be effectively reduced and the steam can be supplied with its temperature, humidity, pressure, and the like adjusted so that the steam can effectively reduce the partial pressure of carbon dioxide in the second internal space 32b and humidify the carbon dioxide separation membrane 34.

[0249] As shown in Fig. 8, the steam supply unit 40 includes a steam generator 41 with a built-in heater, and a pump 42. More specifically, one end (downstream side) of the steam generator 41 is connected to the carbon dioxide separation unit 30 via a pipe P42. More specifically, the steam generator 41 is connected to the second internal space 32b side of the carbon dioxide separation unit 30 via the pipe P42. Furthermore, one end (upstream side) of the pump 42 is connected to a supply water introduction pipe P43, and the other end (downstream side) is connected to the steam generator 41 via a pipe P44. In other words, compared to the steam supply unit 4 of the gas recovery apparatus 1, the steam supply unit 40 does not adopt a configuration in which carbon dioxide in the storage tank 54 is supplied to the carbon dioxide separation unit 30 via the steam generator 41.

[0250] The steam generator 41 and the pump 42 are electrically connected to the processing device 8 and are controlled based on control signals transmitted from the processing device 8 .

[0251] With such a configuration of the steam supply unit 40, the pump 42 is constantly driven, supplying the supply water to the steam generator 41, and generating steam at a predetermined temperature in the steam generator 41. The generated steam is then supplied to the carbon dioxide separation unit 30 via a pipe P42. Here, the predetermined temperature is the same as or is determined according to the operating temperature of the carbon dioxide separation unit 30 in the gas recovery device 501.

[0252] Furthermore, by controlling the operating rate of the steam generator 41, the operating rate of the pump 42, or a combination thereof based on a control signal generated from the processing device 8 in accordance with the target steam supply state, it is possible to control the state or amount of steam generated in the steam supply unit 40, the state or amount of steam introduced from the steam supply unit 40 to the carbon dioxide separation unit 30, or a combination thereof. This makes it possible to reduce the energy cost for the amount of energy for steam generation, the amount of energy for steam removal, the amount of energy for steam compression, or a combination thereof, and to reduce the overall energy cost of the gas recovery device 1.

[0253] As described above, the steam supply unit 40 has a steam generator 41 with a built-in heater, which heats the supply water to generate steam. Therefore, a heat source for supplying heat used to heat the supply water is connected to the steam generator 41 via a pipe. That is, in this embodiment, the pipe functions as a heat or cold heat supplier. By supplying heat from the heat source to the steam generator 41 via the pipe, it is possible to heat the supply water to a predetermined temperature range.

[0254] Although the above description has been given of a case where the piping connected to the steam generator 41 is used as a heat or cold heat supplier, it is also possible to configure a heat or cold heat supplier by other methods. For example, the steam generator 41 itself, the steam generator 41 and its surrounding piping P43 and piping P42, or the entire steam supply unit 40 are housed in a container that can be filled with heat. Heat is then supplied from a heat source to the container via the connected piping. In other words, the container and the piping function as a heat or cold heat supplier. This makes it possible to maintain the temperature of the steam heated by the steam generator 41 or to assist in maintaining or maintaining the temperature of the steam.

[0255] The heat source of the heat or cold heat supplier can be derived from outside or inside the gas recovery device 1, similar to the heat exchanger 21. A detailed description is omitted here, as it is the same as the heat source of the heat exchanger 21.

[0256] Furthermore, the steam supply unit 40 may be incorporated into the humidity adjustment unit 2 described above. That is, the humidity adjustment unit 2 may include the steam supply unit 40, and the function of the steam supply unit 40 may be performed by the humidity adjustment unit 2. When the carbon dioxide concentration of the supply gas is sufficiently low, the amount of carbon dioxide permeation is also small, and the amount of water vapor permeating from the first internal space 32a to the second internal space 32b in the carbon dioxide separation unit 30 is sufficient to reduce the partial pressure and perform the role of humidification. In such a case, it can be said that the function of the steam supply unit 40 is performed by the humidity adjustment unit 2.

[0257] (Carbon dioxide capture unit 50) As shown in FIG. 8 , the carbon dioxide capture unit 50 includes a pump 51, a heat exchanger 52, a gas-liquid separator 53, and a storage tank 54. More specifically, one end (upstream side) of the pump 51 is connected to the carbon dioxide separation unit 30 via a pipe P51, and the other end (downstream side) is connected to the heat exchanger 52 via a pipe P52. In particular, the pump 51 is connected to the second internal space 32b side of the carbon dioxide separation unit 30 via the pipe P51. Furthermore, the gas-liquid separator 53 is connected to the downstream side of the heat exchanger 52 via a pipe P53. Furthermore, the storage tank 54 is connected to the downstream side of the gas-liquid separator 53 via a pipe P54 and a pipe P58. A pipe P55 for sending wastewater to the outside is connected to the gas-liquid separator 53.

[0258] With the carbon dioxide capture unit 50 configured as described above, the pressure inside the gas capture device 1 is reduced by driving the pump 51, and the introduced gas (carbon dioxide and water vapor) introduced toward the carbon dioxide capture unit 50 by this reduced pressure is heated or cooled by the heat exchanger 52 depending on the temperature of these gases, and the temperature is adjusted to a predetermined temperature range before being supplied to the gas-liquid separator 53. For example, when the introduced gas is cooled by the heat exchanger 52, the water vapor contained in the introduced gas is condensed and separated as water. Here, the predetermined temperature range is determined depending on the operating temperature of the carbon dioxide separation unit 30 in the gas capture device 501. For example, the predetermined temperature range is −78°C to 60°C.

[0259] In the gas-liquid separator 53, moisture is removed from the introduced gas, and the removed moisture is sent out as wastewater from the pipe P55. More specifically, when the water vapor is condensed and separated into water by the heat exchanger 52, the water is separated from the gas as condensed water in the gas-liquid separator 53, and the condensed water is discharged as wastewater. As a result, the moisture content of the introduced gas passing through the gas-liquid separator 53 is adjusted so that the proportion of carbon dioxide is increased, and the introduced gas is supplied to the storage tank 54 via the pipes P54 and P58.

[0260] The pump 51 and the heat exchanger 52 are electrically connected to the processing device 8 and are controlled based on control signals sent from the processing device 8 .

[0261] Furthermore, the operating state of the pump 51, the operating state of the heat exchanger 52, or a combination thereof can be controlled based on a control signal generated from the processing device 8 in accordance with the target steam supply state, thereby controlling the state or amount of steam introduced from the steam supply unit 40 to the carbon dioxide separation unit 30. This reduces the amount of steam supplied, and reduces the amount of energy for steam generation, the amount of energy for steam removal, the amount of energy for steam compression, or a combination thereof, making it possible to reduce the overall energy cost of the gas recovery device 1.

[0262] As described above, the carbon dioxide recovery unit 50 heats or cools the introduced gas to a predetermined temperature range using the heat exchanger 52. Therefore, a heat source or cold source for heating or cooling is connected to the heat exchanger 52 via a pipe. That is, in this embodiment, the pipe functions as a heat or cold supplier. By supplying heat or cold from the heat source or cold source to the heat exchanger 52 via the pipe, it is possible to heat or cool the introduced gas to a predetermined temperature range.

[0263] Although the above description has been given of a case in which piping connected to the heat exchanger 52 is used as a heat or cold supplier, it is also possible to configure a heat or cold supplier by other methods. For example, the heat exchanger 52 itself, the heat exchanger 52 and the surrounding inlet piping P52 and piping P53, or the entire carbon dioxide recovery unit 50 are housed in a container that can be filled with heat or cold. Heat or cold is then supplied to the container from a heat source or cold source via the connected piping. In other words, the container and piping function as a heat or cold supplier. This makes it possible to heat or cool using the heat exchanger 52, and to maintain the temperature of the heated or cooled inlet gas, or to assist in these operations.

[0264] The heat source or cold source of the heat or cold supplied to the heat or cold heat supplier can be derived from outside or inside the gas recovery device 1, similar to the heat exchanger 21. A detailed description is omitted here, as it is the same as the heat source of the heat exchanger 21.

[0265] The configuration and function of the carbon dioxide capture unit 50 as described above not only adjusts the temperature of the stored carbon dioxide but also removes unnecessary moisture, allowing high-concentration carbon dioxide to be stored in the storage tank 54. If temperature adjustment is not required, the heat exchanger 52 need not be provided. The positional relationship between the pump 51 and the heat exchanger 52 may be reversed, and the temperature-adjusted introduction gas may be drawn in by the pump 51. Furthermore, the number of pumps 51 and heat exchangers 52 is not limited to one, and multiple pumps 51 and multiple heat exchangers 52 may be provided depending on the amount of introduction gas drawn in and the temperature adjustment, and the number of pumps 51 and heat exchangers 52 may be adjusted appropriately. The storage tank 54 is not required, and the storage tank 54 may be directly connected to a carbon dioxide reduction device (not shown). It is also possible to store the carbon dioxide as liquefied carbon dioxide or dry ice by pressurizing or cooling it as needed.

[0266] (Carbon dioxide recovery flow) Next, a description will be given of the carbon dioxide recovery flow in the gas recovery device 501. In a series of processes related to the recovery, the processor 82 of the processing device 8 executes each process based on the same process flow as in Figures 3A and 3B.

[0267] The processor 82 of the processing device 8 accepts operation input from an operator via the input interface 85 and initiates a series of processes for separating and recovering carbon dioxide from the supply gas by the gas recovery device 501. The processor 82 then generates control signals for adjusting the relative humidity and sorbing carbon dioxide, and drives the pumps 11 and 51. As a result, a supply gas containing carbon dioxide and having a temperature of approximately 80°C is supplied from the inlet pipe P21. Cold is supplied to the heat exchanger 21 from a cold source via a refrigerant in the pipe. Therefore, the supply gas is cooled to approximately 50°C in the heat exchanger 21. Here, the supply gas is assumed to be a gas obtained by burning methane gas, with a carbon dioxide concentration of approximately 7% and a moisture concentration of approximately 14%. Such a supply gas has a saturated water vapor pressure equivalent to 50°C at 1 atmosphere.

[0268] The cooled supply gas is introduced into the gas-liquid separator 22 via pipe P22. As described above, the supply gas has a saturated water vapor pressure equal to that of 50°C at 1 atmosphere, so moisture is removed in the gas-liquid separator 22, and the removed moisture is discharged as wastewater from pipe P26. This completes the relative humidity adjustment process, which dehumidifies the supply gas containing carbon dioxide to adjust its relative humidity. The supply gas from which moisture has been removed is then introduced into the carbon dioxide separation unit 30 via pipe P25 at a relative humidity of 80% or more (e.g., 90%). In particular, in this embodiment, since pipe P25 is connected to the first internal space 32a side, the supply gas is supplied to the first internal space 32a side.

[0269] Here, similar to S113 and S114 of FIG. 3A , the processor 82 monitors the supply rate of the supply gas supplied from the supply gas supply unit 9 and determines whether the supply rate exceeds the target supply rate of the supply gas. If the processor 82 determines that the supply rate exceeds the target supply rate, similar to S115 of FIG. 3A , the processor 82 sends a control signal to the pump 11 to control the output of the pump 11 (reduce the output). The method of controlling the output is the same as the method shown in FIG. 3A . Here, the processor 82 determines only whether the target supply rate (upper limit) of the supply gas has been exceeded. However, it is also possible to further determine whether the target supply rate (lower limit) of the supply gas has been exceeded, and if so, to control the amount of the supply gas to be increased. Here, the case where the supply rate and target supply rate of the supply gas are used as an example of the supply state and target supply state of the supply gas is described. However, similar processing is also possible when the supply temperature and pressure of the supply gas, or the target supply temperature and target supply pressure, are used.

[0270] Meanwhile, because the pump 42 continues to operate, the supply water is supplied to the steam generator 41 via the pipe P43, the pump 42, and the pipe P44, and steam is continuously generated in the steam generator 41. Then, because the pump 51 also continues to operate, the steam generated in the steam generator 41 is drawn into the second internal space 32b of the carbon dioxide separation unit 30. That is, steam is continuously supplied to the second internal space 32b of the carbon dioxide separation unit 30.

[0271] In the carbon dioxide separation unit 30, the supply gas containing carbon dioxide is present on the first internal space 32a side, and the steam is present on the second internal space 32b side. From the supply gas in the first internal space 32a, only carbon dioxide is selectively transmitted into the first internal space 32a by the carbon dioxide separation membrane 34 (the direction of the arrow in the carbon dioxide separation unit 30 in FIG. 8). At this time, the carbon dioxide concentration on the second internal space 32b side increases because carbon dioxide selectively transmits, but the partial pressure difference can be maintained by lowering the partial pressure with steam supplied from the steam supply unit 40.

[0272] Thereafter, the carbon dioxide that has flowed into the second internal space 32b side is reduced in pressure by driving the pump 51, and is introduced into the heat exchanger 52 via the pipe P51, the pump 51, and the pipe P52. At this time, the processor 82 of the treatment device 8 generates a control signal for controlling the temperature in the heat exchanger 52 to adjust the cooling temperature of the carbon dioxide, and sends the control signal to the heat exchanger 52. In addition, cold is supplied to the heat exchanger 52 from a cold source via the refrigerant in the pipe. Therefore, when the carbon dioxide and steam are introduced into the heat exchanger 52 of the carbon dioxide recovery unit 50, they are cooled to a predetermined temperature by the heat exchanger 52 in order to remove water vapor from the carbon dioxide.

[0273] The carbon dioxide and steam cooled to a predetermined temperature in the heat exchanger 52 are introduced into the gas-liquid separator 53 via pipe P53. Here, some of the moisture is removed in the gas-liquid separator 53. As a result, the gas passing through the gas-liquid separator 53 has an increased carbon dioxide concentration. The carbon dioxide that has passed through the gas-liquid separator 53 is then introduced into the storage tank 54 via pipes P54 and P58. As a result, high-concentration carbon dioxide (concentrated carbon dioxide) is stored in the storage tank 54. This makes it possible to recover the carbon dioxide released from the carbon dioxide separation unit 30 while removing the steam.

[0274] Here, similar to S131 and S132 of Fig. 3B , the processor 82 monitors the amount of steam generated in the steam supply unit 40 or the amount of steam supplied from the steam supply unit 40, and determines whether or not the amount exceeds the target supply amount. If it is determined that the amount exceeds the target supply amount, the processor 82 sends a control signal to the pump 51 to control the output of the pump 51 (reduce the output), similar to S133 of Fig. 3B . The method of controlling the output is the same as the method shown in Fig. 3B .

[0275] 3B, the processor 82 transmits control signals to the steam generator 41, the pump 42, and the heat exchanger 52 to control the respective components. The control method is the same as the method shown in FIG. 3B.

[0276] Here, the processor 82 only determines whether the target steam supply amount (upper limit) has been exceeded, but it is also possible to further determine whether the target steam supply amount (lower limit) has been exceeded, and to control the amount of steam to increase if it has been exceeded. Also, here, a case has been described in which the steam supply amount and target supply amount are used as an example of the steam supply state and target supply state, but similar processing is also possible when the steam supply temperature and pressure, and the target supply temperature and target supply pressure are used.

[0277] Meanwhile, the residual gas that cannot permeate the carbon dioxide separation membrane 34 is led to the heat exchanger 61 of the residual gas discharge unit 6 via the pipe P61. Here, cold heat is supplied to the heat exchanger 61 from a cold heat source through the refrigerant in the pipe. Therefore, when the residual gas is introduced into the heat exchanger 61 of the residual gas discharge unit 6, the residual gas is cooled to approximately 24°C in the heat exchanger 61 so that the residual gas can be discharged from the gas recovery device 501. Here, the cooling temperature is not limited to 24°C, and it is assumed that the residual gas discharge condition requires that the temperature of the residual gas be room temperature.

[0278] The residual gas cooled to 24°C in the heat exchanger 61 is introduced into the gas-liquid separator 62 via pipe P62. Here, the residual gas contains a large amount of moisture because the relative humidity of the residual gas was approximately 80% or higher even when it was in the state of a supply gas (containing carbon dioxide). Therefore, the cooled residual gas contains a large amount of water vapor, and moisture is removed from the residual gas in the gas-liquid separator 62. The removed moisture is discharged as wastewater from pipe P64. Meanwhile, the residual gas from which moisture has been removed is discharged to the outside of the gas recovery device 1 via exhaust pipe P63.

[0279] By successively performing the relative humidity adjustment step, separation step, and recovery step, the storage tank 54 can be filled with carbon dioxide at a higher concentration. In other words, recovery of carbon dioxide at a high concentration is achieved.

[0280] In the above embodiment, the carbon dioxide separation unit 30 is described as having a substantially cylindrical housing 31, but the present invention is not limited to this. For example, as other forms of using the carbon dioxide separation membrane 34, a module in which flat membranes are stacked, a hollow fiber module, or a spiral module may be used.

[0281] The specific configurations of the heat exchangers 21, 52, 61 and the steam generator 41 are not limited to those described in the above embodiment. While a liquid circulation type is shown in Fig. 7A, various types, such as a partition wall type, a thermal storage type, a direct contact type, and a heat pipe type, can be used. The heat medium or refrigerant 92 is, for example, a fluid, and specific examples thereof include steam, water, air, and liquefied natural gas.

[0282] The specific configurations of the pumps 11, 23, 42, and 51 are not limited to those described in the above embodiments. For example, a reciprocating pump, a liquid ring pump, an oil rotary pump, a roots pump, a dry pump, a cryopump, a peristaltic pump, a diaphragm pump, or the like can be used. Also, a fan or blower, such as a multi-blade fan, a centrifugal fan / blowers, an axial fan / blowers, or a mixed flow blower, can be used instead of the pump. The flow rate of the pump can be controlled by any method. For example, heat quantity control or needle valve control can be used, and a flow measurement mechanism such as a throttling method, a fluid resistance method, an ultrasonic method, a thermal method, a volumetric method, a kinetic energy method, a laser Doppler method, or an inverter control method can be used in combination depending on the control flow rate.

[0283] The pressure control in the gas recovery device 1, 501 can be performed by any method, such as a liquid column method, an elastic body method, a force balance method, a sinking bell method, a Pitot tube method, or flow rate control of a circulating gas circuit.

[0284] 5. Use of the Gas Recovery Apparatus 1, 501 as a Heat or Cold Source As described above, the gas recovery apparatus 1 includes the supply gas supply unit 9, humidity adjustment unit 2, steam supply unit 4, carbon dioxide recovery unit 5, and residual gas discharge unit 6. In particular, heat or cold is generated by heat exchange in the heat exchanger 21 of the humidity adjustment unit 2, the heat exchanger 52 of the carbon dioxide recovery unit, and the heat exchanger 61 of the residual gas discharge unit 6. Furthermore, in the steam supply unit 4, the supply water used to generate steam can be used as a cold source. Furthermore, in the residual gas discharge unit 6, the generated high-temperature residual gas can be used as a heat medium. The gas recovery apparatus 1 uses the heat or cold supplier shown in FIG. 7A , but the side opposite to the side installed in the gas recovery apparatus 1 is installed outside a power generation facility, factory facility, electrical facility, or the like. This makes it possible to use the humidity adjustment unit 2, steam supply unit 4, carbon dioxide recovery unit 5, and residual gas discharge unit 6 as a heat or cold source to supply heat or cold to the outside.

[0285] 6. Relationship between exhaust gas supply amount and energy cost In the gas recovery device 1, the energy cost required for humidification or steam generation was calculated when the exhaust gas supply amount was changed under specified conditions. The energy cost is the energy cost per unit amount of recovered carbon dioxide. The purity of the carbon dioxide recovered at this time was also measured. Any conditions other than the exhaust gas supply amount may be used as long as they are fixed. However, the carbon dioxide content of the supplied exhaust gas is 10%.

[0286] FIG. 9 is a diagram showing the relationship between the exhaust gas supply amount, energy cost, and carbon dioxide purity. When the exhaust gas supply amount is 15 SLM, the energy cost is 2.64 GJ / t. The resulting carbon dioxide purity is 97.4%. When the exhaust gas supply amount is 10 SLM, the energy cost is 1.65 GJ / t. The resulting carbon dioxide purity is 97.5%. When the exhaust gas supply amount is 7 SLM, the energy cost is 1.93 GJ / t. The resulting carbon dioxide purity is 96.7%. These results demonstrate that changing the exhaust gas supply amount changes the energy cost. For example, when the exhaust gas supply amount is relatively large, it is necessary to generate a large amount of steam. In this case, it is believed that the energy required for steam generation increases. Furthermore, when the exhaust gas supply amount is relatively small, the amount of carbon dioxide recovered is small, and as a result, it is believed that the carbon dioxide recovery efficiency decreases. In other words, by setting the exhaust gas supply amount to an appropriate amount, the energy cost and carbon dioxide purity can be optimized. In other words, it is possible to determine the target supply state of the supply gas in order to optimize at least one of the energy cost and the carbon dioxide purity. In other words, the target supply amount (target supply state) may be set in advance according to either the optimal energy cost or the desired carbon dioxide purity. Note that the amount of exhaust gas supply that minimizes the energy cost depends on the specifications of the gas recovery device 1 and the conditions during carbon dioxide recovery.

[0287] 7. Relationship between steam supply amount, energy cost, and carbon dioxide purity In the gas recovery device 1, the energy cost required for humidification or steam generation was calculated when the amount of steam generated by the steam generator 41 was changed under specified conditions. The energy cost is the energy cost per unit amount of recovered carbon dioxide. The purity of the carbon dioxide recovered at this time was also measured. Any conditions other than the amount of steam generated may be used as long as they are fixed. However, the carbon dioxide content of the supplied exhaust gas is 10%.

[0288] FIG. 10 is a diagram showing the relationship between the amount of steam generated, the energy cost, and the purity of carbon dioxide. When the amount of steam is 1 SLM, the energy cost is 2.04 GJ / t. In this case, the purity of the recovered carbon dioxide is 96.7%. When the amount of steam is 0.5 SLM, the energy cost is 1.12 GJ / t. In this case, the purity of the recovered carbon dioxide is 95.4%. When the amount of steam is 0.3 SLM, the energy cost is 0.86 GJ / t. In this case, the purity of the recovered carbon dioxide is 94.7%. From these results, it can be seen that the energy cost and the purity of the recovered carbon dioxide change when the amount of steam generated is changed. For example, when the amount of steam generated is relatively small, the energy cost decreases. Furthermore, the purity of the recovered carbon dioxide also decreases. On the other hand, when the amount of steam generated is large, the energy cost increases. In other words, by setting the amount of steam generated in the steam generator 41 to an appropriate amount, carbon dioxide of the desired purity can be recovered. In other words, it is possible to determine the amount of steam to be supplied, which is an example of a target supply state, in order to optimize at least one of the energy cost and the purity of carbon dioxide. In other words, the target supply amount (target supply state) may be set in advance according to either the optimal energy cost or the desired purity of carbon dioxide. Note that the energy cost resulting from the amount of steam generated in the steam generator 41, or the purity of carbon dioxide recovered, depends on the specifications of the gas recovery device 1 and the conditions during carbon dioxide recovery.

[0289] 8. Summary of Embodiments of the Present Disclosure A gas recovery apparatus 1,501 according to an embodiment of the present disclosure is a gas recovery apparatus 1,501 for separating carbon dioxide from a supply gas containing carbon dioxide to recover the carbon dioxide, and includes a carbon dioxide separation unit 3, 30 having a carbon dioxide separator and configured to separate carbon dioxide from the supply gas, a steam supply unit 4, 40 configured to supply steam to the carbon dioxide separation unit 3, 30 and generate steam to reduce the partial pressure of carbon dioxide in the carbon dioxide separation unit 3, 30, and a control unit 82 configured to control the state or amount of at least one of the steam supplied from the steam supply unit 4, 40 and the steam generated in the steam supply unit 4, 40.

[0290] Furthermore, a gas recovery method according to an embodiment of the present disclosure is a gas recovery method for recovering carbon dioxide by separating it from a supply gas containing carbon dioxide, and includes a carbon dioxide separation process for separating carbon dioxide from the supply gas in a carbon dioxide separation unit (3, 30) having a carbon dioxide separator, and a steam supply process for supplying steam to the carbon dioxide separation unit (3, 30) to generate steam to reduce the partial pressure of carbon dioxide in the carbon dioxide separation unit (3, 30), and the state or amount of at least one of the steam supplied and the steam generated in the steam supply process is controlled by a control unit.

[0291] A gas recovery apparatus 1,501 according to an embodiment of the present disclosure is a gas recovery apparatus 1,501 for recovering carbon dioxide by separating carbon dioxide from a supply gas containing carbon dioxide, and includes a carbon dioxide separation unit 3,30 having a carbon dioxide separator and configured to separate carbon dioxide from the supply gas, a supply gas supply unit 9 connected to the carbon dioxide separation unit 3,30 and configured to supply the supply gas to the carbon dioxide separation unit 3,30, and a control unit 82 configured to control the state or amount of the supply gas supplied from the supply gas supply unit 9.

[0292] Furthermore, a gas recovery method according to an embodiment of the present disclosure is a gas recovery method for recovering carbon dioxide by separating it from a supply gas containing carbon dioxide, and includes a carbon dioxide separation process for separating carbon dioxide from the supply gas in a carbon dioxide separation unit (3, 30) having a carbon dioxide separator, and a supply gas supply process connected to the carbon dioxide separation unit (3, 30) for supplying the supply gas to the carbon dioxide separation unit (3, 30), and the state or amount of the supply gas supplied in the supply gas supply process is controlled by a control unit.

[0293] According to such an embodiment, it is possible to provide a gas recovery device and a gas recovery method that can reduce energy costs.

[0294] The processes and procedures described herein can be realized not only by those explicitly described in this disclosure, but also by software, hardware, or a combination thereof. Specifically, the processes and procedures described herein can be realized by implementing logic corresponding to the processes in a medium such as an integrated circuit, volatile memory, non-volatile memory, magnetic disk, or optical storage. Furthermore, the processes and procedures described herein can be implemented as computer programs and executed by various computers, including terminal devices and server devices.

[0295] Although processes and procedures described herein are described as being performed by a single device, software, component, or module, such processes or procedures may be performed by multiple devices, multiple software, multiple components, and / or multiple modules. Furthermore, although various information described herein is described as being stored in a single memory or storage unit, such information may be stored in multiple memories within a single device or multiple memories distributed across multiple devices. Furthermore, software and hardware elements described herein may be realized by integrating them into fewer components or by decomposing them into more components.

[0296] REFERENCE SIGNS LIST 1 Gas recovery device 2 Humidity adjustment section 3, 30 Carbon dioxide separation section 4, 40 Steam supply section 5, 50 Carbon dioxide recovery section 6 Residual gas discharge section 7 Retained gas recovery section 9 Supply gas supply section

Claims

1. A gas recovery apparatus for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, comprising: a carbon dioxide separation section having a carbon dioxide separator and configured to separate the carbon dioxide from the supply gas; a steam supply section configured to supply steam to the carbon dioxide separation section and generate the steam to reduce the partial pressure of the carbon dioxide in the carbon dioxide separation section; and a control section configured to control the state or amount of the steam supplied from the steam supply section.

2. The gas recovery device according to claim 1, wherein the control unit is configured to control the state or amount of the vapor based on a predetermined target supply state.

3. A gas recovery device as described in claim 1, wherein the control unit is configured to control the state or amount of the steam supplied by adjusting at least one of the amount of heat, pressure, and temperature applied in the steam supply unit.

4. A gas recovery device as described in claim 1, further comprising at least one of a pump and a valve configured to be driven under the control of the control unit to supply the steam generated in the steam supply unit to the carbon dioxide separation unit, and the control unit configured to control the state or amount of the steam by adjusting at least one of the operating rate of the pump and the opening degree of the valve.

5. A gas recovery apparatus for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, comprising: a carbon dioxide separation section having a carbon dioxide separator and configured to separate the carbon dioxide from the supply gas; a supply gas supply section connected to the carbon dioxide separation section and configured to supply the supply gas to the carbon dioxide separation section; and a control section configured to control the state or amount of the supply gas supplied from the supply gas supply section.

6. The gas recovery device according to claim 5, wherein the control unit is configured to control the state or amount of the supply gas based on a predetermined target supply state.

7. The gas recovery device according to claim 5, wherein the supply gas supply unit includes at least one of a pump and a valve for supplying the supply gas, and the control unit is configured to control the state or amount of the supply gas by adjusting at least one of the operation rate of the pump and the opening degree of the valve.

8. A gas recovery method for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, comprising: a carbon dioxide separation step of separating the carbon dioxide from the supply gas in a carbon dioxide separation section having a carbon dioxide separator; and a steam supply step of supplying steam to the carbon dioxide separation section to generate the steam in order to reduce the partial pressure of the carbon dioxide in the carbon dioxide separation section, wherein a control unit controls the state or amount of the steam supplied in the steam supply step.

9. A gas recovery method for separating carbon dioxide from a supply gas containing carbon dioxide and recovering the carbon dioxide, comprising: a carbon dioxide separation step of separating the carbon dioxide from the supply gas in a carbon dioxide separation unit having a carbon dioxide separator; and a supply gas supply step connected to the carbon dioxide separation unit and supplying the supply gas to the carbon dioxide separation unit, wherein a state or amount of the supply gas supplied in the supply gas supply step is controlled by a control unit.

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