Carbon dioxide separation apparatus and carbon dioxide separation method

Abstract

[Problem] To provide a carbon dioxide gas separation device and a carbon dioxide gas separation method which make it possible to efficiently separate water from an exhaust gas which contains carbon dioxide gas. [Solution] A carbon dioxide gas separation device 1 has: an oxygen supply unit 10A; a combustion unit 12 comprising a combustion furnace 12A which is supplied with oxygen from the oxygen supply unit 10A and in which said oxygen is combusted together with supplied fuel, and a dehumidifier 40 which separates water from a combustion gas which has been generated in the combustion furnace 12A and which contains the water and carbon dioxide gas; and a water separation unit 15 into which the exhaust gas discharged from the combustion unit 12 is introduced and which separates remaining water from the exhaust gas. The water separation unit 15 is provided between the oxygen supply unit and the combustion furnace and comprises: an oxygen introduction port for introducing dry oxygen which is supplied from the oxygen supply unit 10A, an oxygen discharge port for discharging oxygen, which contains water, to the combustion unit, an exhaust gas introduction port for introducing the exhaust gas which has been discharged from the combustion unit and contains water and carbon dioxide gas; and an exhaust gas discharge port for discharging dry exhaust gas from which the water has been removed.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide separation device that can be installed in, for example, factories, power plants, hydrogen gas stations, etc., and separates and recovers carbon dioxide from exhaust gas, and a carbon dioxide separation method for separating carbon dioxide from exhaust gas.

Background Art

[0002] In recent years, in order to achieve a decarbonized society, technologies for separating and recovering carbon dioxide from combustion exhaust gas have been desired. As a technology for separating and recovering carbon dioxide (carbon dioxide) from combustion exhaust gas, an oxygen combustion method that combines oxygen combustion, which can be expected to improve efficiency, and a gas separation device is known.

[0003] As the oxygen combustion method, various methods are known. For example, Patent Document 1 discloses an exhaust gas treatment system including a compressor that makes exhaust gas water-soluble, a cooler that cools the compressed exhaust gas, condenses moisture, and removes drain in which impurities are dissolved, and a dryer. Further, Patent Document 2 discloses an exhaust gas treatment system including a heat recovery device that recovers heat from exhaust gas and a cooling and dehumidifying device that removes moisture in the exhaust gas.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In oxygen combustion, carbon dioxide is separated and recovered by passing exhaust gas through a gas separation device equipped with an adsorbent. However, gas separation devices using adsorbents have a problem in that their ability to adsorb carbon dioxide gradually decreases because they adsorb moisture. This is because their performance deteriorates when exhaust gas containing moisture is continuously supplied. To avoid such problems, one might consider installing a dehumidifier before the gas separation unit to remove moisture from the exhaust gas, but this would require a large amount of power and would be inefficient.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide a carbon dioxide separation apparatus and a carbon dioxide separation method that can efficiently separate water from exhaust gas containing carbon dioxide. [Means for solving the problem]

[0007] In order to achieve the above-mentioned objectives, the present invention The first aspect The carbon dioxide separation device is A first gas supply unit that supplies the first drying gas, The second gas supply unit supplies the second gas, The first gas is supplied from the first gas supply unit, and the reaction takes place together with the second gas. combustion furnace And, as stated above combustion furnace A dehumidifier that separates moisture from the generated gas containing water and carbon dioxide produced therein. Combustion section and, Dehumidifying gas discharged from the dehumidifier in the combustion section is introduced, and any remaining moisture in the dehumidifying gas is removed. Adsorbent It has a moisture separation unit that separates the moisture, The moisture separation unit comprises the first gas supply unit and the combustion furnace A first gas inlet is provided between the first gas supply unit and the first dry gas supplied from the first gas supply unit, The aforementioned To the combustion furnace A first gas outlet for discharging a first gas containing moisture, The aforementioned combustion furnace A gas inlet for introducing dehumidifying gas containing at least moisture and carbon dioxide, which is exhausted from the source, A gas outlet for discharging the dry gas from which moisture has been removed, It is equipped with, A connection line for introducing the drying first gas from the first gas supply unit into the first gas inlet 15a, A connection line for introducing the first gas, from which the adsorbent has been dehumidified, into the combustion furnace from the first gas outlet, The dehumidifier is equipped with a connecting line that introduces the dehumidifying generated gas 5) containing at least moisture and carbon dioxide, exhausted from the dehumidifier, into the generated gas inlet, The dry first gas is either oxygen or fuel. It is characterized by the following:

[0008] In the carbon dioxide separation apparatus with the above configuration, the dehumidified product gas discharged from the reaction section is introduced into the moisture separation section via the product gas inlet, where moisture is separated and recovered, and a high-concentration product gas (carbon dioxide) is discharged from the product gas outlet. In this moisture separation section, the dry state is maintained by the drying first gas supplied from the first gas supply section via the first gas inlet, so the moisture separation performance does not deteriorate. In other words, the moisture separation section can efficiently maintain a dry state with a simple structure, eliminating the need to install a dedicated dehumidifier and requiring no large amount of power, thus making it possible to miniaturize the entire apparatus.

[0009] Furthermore, in order to achieve the above-mentioned objectives, the carbon dioxide separation method according to the present invention is Using the carbon dioxide separation apparatus of the first embodiment, Dry gas No. 1 supplied from No. 1 gas supply unit and gas No. 2 supplied from No. 2 gas supply unit Combustion section in combustion Perform combustion The process, The aforementioned combustion A drying process in which the generated gas discharged during the process is passed through a moisture separation section to separate the moisture, A humidification step is performed by passing the aforementioned dry first gas through a moisture separation section to humidify it. It is characterized by having the following:

[0010] According to the carbon dioxide separation method having the above-described configuration, in the reaction step, the generated gas discharged is such that moisture is separated and recovered in the drying step, and high-concentration carbon dioxide is discharged. In this drying step, moisture is supplied to the moisture separation section, but since the moisture is removed from the moisture separation section by the dried first gas supplied from the first gas supply section in the humidifying step, the separation performance of the moisture does not deteriorate. That is, in the moisture separation step, the moisture is efficiently separated from the dehumidified generated gas with a simple structure that only allows the dehumidified generated gas to pass through the moisture separation section, and it is possible to reduce the size of the entire carbon dioxide separation apparatus without requiring a large amount of power.

Advantages of the Invention

[0011] According to the present invention, a carbon dioxide separation apparatus and a carbon dioxide separation method capable of efficiently separating moisture from exhaust gas containing carbon dioxide can be obtained.

Brief Description of the Drawings

[0012] [Figure 1A] It is a schematic diagram showing a first embodiment of a carbon dioxide separation apparatus according to the present invention. [Figure 1B] It is a schematic diagram showing a modification of the first embodiment of a carbon dioxide separation apparatus according to the present invention. [Figure 2] It is a schematic diagram (part 1) showing a schematic configuration example of a moisture separation section incorporated in the carbon dioxide separation apparatus shown in FIG. 1 and its operation. [Figure 3] It is a schematic diagram (part 2) showing a schematic configuration example of a moisture separation section incorporated in the carbon dioxide separation apparatus shown in FIG. 1 and its operation. [Figure 4] It is a schematic diagram showing a second embodiment of a carbon dioxide separation apparatus according to the present invention. [Figure 5] It is a schematic diagram showing a third embodiment of a carbon dioxide separation apparatus according to the present invention. [Figure 6] It is a schematic diagram showing an example of use of a fourth embodiment of a carbon dioxide separation apparatus according to the present invention. [Figure 7] It is a schematic diagram showing a fifth embodiment of a carbon dioxide separation apparatus according to the present invention. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the carbon dioxide separation apparatus according to the present invention will be described with reference to the attached drawings. Figure 1(A) is a schematic diagram showing a first embodiment of the carbon dioxide separation apparatus.

[0014] In this invention, as a method for separating carbon dioxide, a first gas (e.g., oxygen) and a second gas containing carbon (e.g., fuel) are supplied to a reaction section, which is a combustion section, to carry out a reaction (combustion), and carbon dioxide (CO2) is separated and recovered from the emitted product (combustion) gas (exhaust gas). In other words, there are various methods for separating and recovering carbon dioxide (CO2) from the generated gas, but in the carbon dioxide separation apparatus and carbon dioxide separation method of this embodiment, when the first gas is oxygen (O2) and the second gas is fuel, these are reacted (combusted) to produce a generated gas containing a high concentration of carbon dioxide with less nitrogen than the apparatus and method that burn air and fuel, and this is further concentrated to separate and recover carbon dioxide (CO2).

[0015] [First Embodiment] As shown in Figure 1(A), the carbon dioxide separation apparatus of the first embodiment includes a first gas supply unit (oxygen supply unit) 10A that supplies oxygen (O2), which is the first gas; a second gas supply unit (fuel supply unit) 10B that supplies fuel F, which is the second gas; a combustion furnace 12A, which is a reaction furnace to which dry oxygen from the first gas supply unit (oxygen supply unit) 10A is supplied and which reacts (combusts) with the fuel F, which is the second gas; a combustion unit 12, which is a reaction unit equipped with a dehumidifier 40 that separates moisture (H2O) from combustion gas G4, which is a product gas containing moisture and carbon dioxide produced in the reaction furnace 12A; and a moisture separation unit 15, which is a dehumidified product gas G5 discharged from the dehumidifier 40 of the combustion unit 12, to which moisture remaining in the exhaust gas G5 is separated.

[0016] The moisture separation unit 15 is provided between the first gas supply unit (oxygen supply unit) 10A and the combustion furnace 12A, and includes a first gas inlet 15a for introducing dry oxygen G2, which is a dry first gas supplied from the first gas supply unit (oxygen supply unit) 10A, a first gas outlet 15b for discharging the first gas (oxygen) G3 containing moisture to the combustion unit 12A, an exhaust gas inlet 15c for introducing exhaust gas G5 containing at least moisture and carbon dioxide exhausted from the combustion unit 12, and an exhaust gas outlet 15d for discharging the dry exhaust gas G6 from which moisture has been removed.

[0017] As shown in Figure 1A, the carbon dioxide separation apparatus 1 of this embodiment includes an oxygen supply unit 10A that takes in air G1 from the outside and generates oxygen, a combustion unit 12 equipped with a combustion furnace 12A to which oxygen from the oxygen supply unit 10A is supplied and combusted together with the supplied fuel, and a moisture separation unit 15 to which exhaust gas G5 discharged from the combustion unit 12 is supplied and moisture is separated.

[0018] The oxygen supply unit 10A, the combustion unit 12, and the moisture separation unit 15 are connected via connecting lines 20, 21, 22A, and 22B, which are, for example, tubular pipes, and are configured to supply the gas processed and generated at each unit to the downstream unit.

[0019] Specifically, the parts and connection lines are as follows: Between the oxygen supply unit 10A and the moisture separation unit 15, there is a connection line 20 that supplies dry oxygen G2 (mainly oxygen (O2), but may also contain other substances such as argon (Ar), and furthermore, it is sufficient that the oxygen concentration is higher than that of air) generated in the oxygen supply unit 10A to the moisture separation unit 15. Also, between the moisture separation unit 15 and the combustion furnace 12A provided in the combustion unit 12, there is a connection line 21 that supplies oxygen G3 (which may contain other substances such as water and argon) that has been dehumidified from the adsorbent provided inside the moisture separation unit 15, as will be described later, to the combustion unit 12. The combustion unit 12 is also equipped with a dehumidifier 40, and between the dehumidifier 40 and the combustion furnace 12A, there is a connection line 22A that supplies combustion gas G4 (which contains carbon dioxide and water, and may also contain other substances such as nitrogen and argon) generated in the combustion furnace 12A to the dehumidifier 40. Furthermore, a connection line 22B is installed between the dehumidifier 40 and the moisture separation unit 15 to supply exhaust gas G5 (which may contain other substances such as nitrogen or argon in addition to carbon dioxide and water) exhausted from the dehumidifier 40 to the moisture separation unit 15.

[0020] The oxygen supply unit 10A can be any device capable of separating oxygen from the intake air G1 (with a nitrogen-to-oxygen ratio of approximately 8:2) and supplying the separated oxygen to the moisture separation unit 15. For example, it can be composed of known devices such as a PSA (Pressure Swing Adsorption) oxygen gas generator, a PVSA (Pressure Vacuum Swing Adsorption) type oxygen gas generator, or a VSA (Vacuum Swing Adsorption) oxygen gas generator. Such a device can repeatedly adsorb and desorb by changing the gas pressure, and remove nitrogen gas (N2) etc. from the air using an adsorbent, thereby separating a high-concentration (preferably 90-95% or higher) dry oxygen gas and supplying it to the moisture separation unit 15.

[0021] The oxygen supply unit 10A is not limited in its configuration as long as it can generate dry oxygen. For example, by using a method that generates liquid oxygen, such as in a cryogenic separation device, it is possible to supply oxygen to the moisture separation unit 15 at an oxygen concentration of approximately 99.9%. Furthermore, regarding the dryness of the supplied oxygen, it is preferable that it has a dew point of -50°C or lower so that the adsorbent provided in the moisture separation unit 15 can be efficiently dried.

[0022] The oxygen G2 (dry oxygen) separated in the oxygen supply unit 10A is supplied to the moisture separation unit 15 via the connection line 20. As will be described later, the moisture separation unit 15 has a function that prevents a decrease in the amount of moisture adsorbed from the exhaust gas G5 discharged from the combustion unit 12 and supplied via the connection line 22B by utilizing the oxygen supplied from the oxygen supply unit 10A (a function that continuously separates and recovers high-concentration carbon dioxide). In other words, the moisture separation unit 15 has a function that separates moisture from the exhaust gas while the adsorbent is dried by the oxygen supplied from the oxygen supply unit 10A.

[0023] Furthermore, the oxygen supplied to the moisture separation unit 15 is supplied to the combustion furnace 12A of the combustion unit 12 via the connection line 21. In the combustion furnace 12A, the necessary thermal energy is obtained by the combustion of oxygen and fuel supplied from the outside. The fuel supplied to the combustion furnace 12A can be any substance containing carbon so that exhaust gas containing carbon dioxide is obtained, for example, hydrocarbon gas, coal, petroleum, etc. can be used. In this case, the combustion furnace 12A should burn the fuel while supplying oxygen containing some moisture through the moisture separation section 15 so that the concentration of carbon dioxide in the exhaust gas is high (oxygen combustion method). For example, an oxygen burner, boiler, or engine can be used as such a combustion furnace 12A.

[0024] The combustion gas G4 produced by combustion in the combustion furnace 12A contains carbon dioxide, water, and other components. This combustion gas G4 is supplied to the water separation unit 15 via a dehumidifier 40 and a connection line 22B to which the pump 22p is installed. As described above, the exhaust gas G5 supplied to the water separation unit 15 has its water adsorbed by an adsorbent installed inside, allowing for the separation of dried exhaust gas G6 (carbon dioxide) which is dried and highly concentrated. The carbon dioxide separated here is then discharged via the discharge line 24.

[0025] Therefore, the moisture separation unit 15 includes an oxygen inlet (first gas inlet) 15a for introducing dry oxygen G2 supplied from the oxygen supply unit 10A, an oxygen outlet 15b for discharging oxygen G3 containing moisture to the combustion unit 12, an exhaust gas inlet 15c for introducing exhaust gas G5 discharged from the combustion unit 12, and an exhaust gas outlet 15d for discharging dry exhaust gas G6.

[0026] In this case, as shown in Figure 1B, a combustion gas G4 circulation line (piping) 22C may be provided to introduce a portion of the combustion gas G4 G4-1 discharged from the combustion furnace 12A back into the combustion furnace 12A. This circulation line 22C branches off from the connection line 22A, which connects the combustion furnace 12A and the dehumidifier 40, before the dehumidifier 40, and is connected to the connection line 21. A pump 22Cp is installed in this circulation line 22C to circulate a portion of the combustion gas G4-1 back into the combustion furnace 12A.

[0027] Normally, in the oxygen combustion method, combustion occurs in the combustion furnace 12A using oxygen gas from which nitrogen has been removed and fuel, resulting in a high combustion temperature that could damage the combustion furnace 12A. Therefore, by providing the circulation line 22C described above, a portion of the combustion gas (carbon dioxide gas containing moisture) G4, G4-1, is returned to the combustion furnace 12A, thereby lowering the combustion temperature. As a result, damage to the combustion furnace 12A can be suppressed. Furthermore, modifications to prevent damage to the combustion furnace become unnecessary. Note that the circulation line 22C may not be provided (see Figures 1A, 2, and 3).

[0028] Figures 2 and 3 are schematic diagrams illustrating a general configuration example of the moisture separation unit 15 according to this embodiment, and its operation. The moisture separation unit 15 of this embodiment uses a PSA-type dehumidifier (dehumidifying PSA). The moisture separation unit 15 is equipped with a plurality of dehumidifying towers (two towers in this embodiment) (first dehumidifying tower 15A, second dehumidifying tower 15B), and each of the first dehumidifying towers 15A and second dehumidifying towers 15B is equipped with an adsorption section containing an adsorbent (for example, a solid adsorbent such as zeolite or silica gel). Furthermore, each dehumidifying tower (each adsorption section) 15A, 15B is equipped with an oxygen inlet, an oxygen outlet, an exhaust gas inlet, and an exhaust gas outlet, and each of the oxygen inlet, oxygen outlet, exhaust gas inlet, and exhaust gas outlet is equipped with an on / off valve, which will be described later.

[0029] In the first dehumidification tower 15A and the second dehumidification tower 15B of this embodiment, a switching structure is provided that allows switching between a state in which dry oxygen G2 from the oxygen supply unit 10A is introduced to one side to dry the adsorbent, and a state in which exhaust gas G5 from the combustion furnace 12A is introduced to the other side. In addition, the dehumidification device may consist of a first dehumidification tower 15A and a second dehumidification tower 15B as one set, and multiple sets of this device may be used.

[0030] The following describes the configuration of the switching structure. Each dehumidification tower (first dehumidification tower 15A, second dehumidification tower 15B) is connected to a connection line 20 and a branch line formed on connection line 22B, respectively. Specifically, connection line 20 includes branch lines 20a and 20b, and each branch line 20a and 20b is connected to the first dehumidification tower 15A and the second dehumidification tower 15B, respectively. Similarly, connection line 22B includes branch lines 22a and 22b, and each branch line 22a and 22b is connected to the first dehumidification tower 15A and the second dehumidification tower 15B, respectively.

[0031] Furthermore, each of the first dehumidification towers 15A and the second dehumidification tower 15B is connected to a connection line 21 and a branch line formed in the discharge line 24, respectively. Specifically, the connection line 21 includes branch lines 21a and 21b, and each branch line 21a and 21b is connected to the first dehumidification tower 15A and the second dehumidification tower 15B, respectively. The discharge line 24 also includes branch lines 24a and 24b, and each branch line 24a and 24b is connected to the first dehumidification tower 15A and the second dehumidification tower 15B, respectively.

[0032] Branch lines 20a, 20b and branch lines 22a, 22b are each provided with on-off valves 30a, 31a and on-off valves 30b, 31b, respectively. Branch lines 21a, 21b and branch lines 24a, 24b are each provided with on-off valves 30c, 31c and on-off valves 30d, 31d, respectively. In this case, in Figures 2 and 3, the open state of valves 30a, 31a, 30b, 31b, 30c, 31c, and 30d, 31d is shown in black, while the closed state is shown in white.

[0033] Here, we will explain the operation of the first dehumidification tower 15A and the second dehumidification tower 15B described above, as well as the open / closed states of each valve constituting the switching structure. Figure 2 is a schematic diagram showing the state in which the first dehumidification tower 15A is in the drying process (a process in which moisture is adsorbed from moist exhaust gas with an adsorbent) and the second dehumidification tower 15B is in the humidification process (a process in which moisture is desorbed from the adsorbent with dry oxygen and the adsorbent is regenerated).

[0034] In the state shown in Figure 2, the on-off valve 30a of the first dehumidification tower 15A is closed and the on-off valve 30b is open. Therefore, dry oxygen G2 is not supplied to the first dehumidification tower 15A from the oxygen supply unit 10A, and combustion gas G4 from the combustion furnace 12A is supplied via the connection line 22B and the branch line 22a. The exhaust gas G5, which contains at least moisture and carbon dioxide and is supplied after passing through the dehumidifier 40, has its moisture adsorbed by the adsorbent in the first dehumidification tower 15A (drying process), and high-concentration carbon dioxide is discharged (recovered) via the branch line 24a and the discharge line 24 through the open on-off valve 30d.

[0035] In this case, it is preferable that the concentration of dry carbon dioxide G6 discharged through the discharge line 24 be, for example, 30% or more. Also, since the shut-off valve 30c is closed, exhaust gas containing a high concentration of carbon dioxide does not flow into the connection line 21 (combustion furnace 12A).

[0036] In the operation of the first dehumidifier tower 15A described above, the on-off valve 31a of the second dehumidifier tower 15B is open, so dry oxygen (O2) G2 is supplied to the dehumidifier tower 15B from the oxygen supply unit 10A via the connection line 20 and the branch line 20b. In this state, since the supplied oxygen is in a dry state, moisture contained in the adsorbent of the dehumidifier tower 15B is desorbed (humidification process). Also, since the on-off valve 31b of the dehumidifier tower 15B is closed, exhaust gas G5 from the combustion furnace 12A does not flow into the dehumidifier tower 15B while it is in the humidification process.

[0037] Furthermore, in this embodiment, dry oxygen (O2) G2 from the oxygen supply unit 10A is introduced into the first dehumidification tower 15A, which is a component of the moisture separation unit 15, to dry the adsorbent, while exhaust gas G5 is introduced into the other second dehumidification tower 15B to adsorb moisture.

[0038] Generally, if a dehumidifying tower into which exhaust gas is introduced is operated continuously, the amount of moisture adsorbed by the adsorbent decreases, which may reduce the concentration of carbon dioxide (CO2) that is separated and recovered. In this embodiment, the dehumidifying tower that performs the drying and humidifying processes is equipped with a switching structure. By switching with this switching structure, the concentration of carbon dioxide (CO2) in the separated and recovered dried exhaust gas G6 is prevented from decreasing.

[0039] Specifically, as shown in Figure 3, by switching the open / closed states of the eight on-off valves 30a to 30d and on-off valves 31a to 31d shown in Figure 2, the drying process is performed in the second dehumidification tower 15B and the humidification process is performed in the first dehumidification tower 15A. This switching between the first dehumidification tower 15A and the second dehumidification tower 15B is performed continuously. As a result, by using a dehumidification tower equipped with an adsorbent that has been dried by dry oxygen (O2) G2 supplied from the oxygen supply unit 10A, it becomes possible to continue adsorbing moisture from the exhaust gas G5. This switching operation does not reduce the amount of moisture adsorbed from the exhaust gas G5, and the concentration of carbon dioxide emitted does not decrease.

[0040] The timing of the switching of the dehumidifying tower described above can be appropriately changed depending on the amount of oxygen supplied from the oxygen supply unit 10A, the drying state, the moisture content of the exhaust gas G5 discharged from the combustion furnace 12A, etc. In this case, for example, the switching operation may be performed at regular intervals after the device has started operating. Alternatively, the moisture content of the dry exhaust gas G6 discharged from the moisture removal device 15 may be detected by a detection means (not shown), and the switch may be performed when it exceeds a certain value (for example, a dew point of -40°C).

[0041] According to the above configuration, dry oxygen (O2) G2 supplied from the oxygen supply unit 10A is used to dry the moist exhaust gas G5 discharged from the combustion furnace 12A, making dehumidification efficient and economical, and reducing the power required to separate and recover carbon dioxide. In other words, in this embodiment, by focusing on the fact that dry oxygen is supplied from the oxygen supply unit 10A for combustion, this oxygen is used to switch between multiple dehumidification towers (first dehumidification tower 15A, second dehumidification tower 15B), which are components of the moisture separation unit 15, to alternately dry the adsorbent, thus improving the efficiency of the device configuration and reducing energy consumption. Furthermore, since there is no need to install a dedicated dehumidification device for exhaust gas, energy consumption does not increase, and the overall size of the device does not increase.

[0042] The moisture separation unit 15 only needs to be configured to dry the exhaust gas, and can be configured using a PSA method as in this embodiment, or a VSA method, TSA (Thermal Swing Adsorption) method, membrane separation method, or a combination of these methods. Furthermore, since it only needs to dry the exhaust gas, it is possible to modify the system as appropriate, such as by using a rotating method with a single dehumidification tower, rather than switching between multiple towers, and there are no limitations on the number of dehumidification towers.

[0043] Furthermore, the dehumidifier 40 generally has the effect of cooling the combustion gas G4, separating the moisture in the combustion gas G4 and increasing the concentration of carbon dioxide in the combustion gas G4, thus reducing the power required for carbon dioxide separation.

[0044] In this embodiment, the first gas was described as oxygen, but the present invention is not limited thereto. Examples of gases containing oxygen atoms other than oxygen include ozone, nitrous oxide, nitric oxide, nitrogen dioxide, chlorine dioxide, and oxygen difluoride. Examples of fuels include hydrocarbons, natural gas, alcohol, petroleum, and coal. Examples of alcohols include methanol, ethanol, propanol, and isopropanol.

[0045] Furthermore, a dehumidifier may be a device that separates moisture by gas-liquid separation through cooling, or it may be a device that separates moisture using a membrane that selectively permeates moisture.

[0046] The carbon dioxide separation method of this embodiment includes a reaction step in which a reaction occurs in a combustion section 12, which is a reaction section, using dry oxygen G2, which is a dry first gas supplied from a first gas supply section 10A, and fuel F, which is a second gas supplied from a second gas supply section; a drying step in which moisture is separated by passing the exhaust gas G5, which is a product gas discharged in this reaction step, through a moisture separation section 15; and a humidification step in which dry oxygen G2, which is a dry first gas, through a moisture separation section 15 to humidify it.

[0047] According to the carbon dioxide separation method of this embodiment, the exhaust gas discharged in the combustion process has its moisture separated and recovered in the drying process, and high-concentration carbon dioxide is discharged. In this drying process, moisture is supplied to the moisture separation unit 15, but since the moisture is removed from the moisture separation unit by the dry oxygen supplied from the oxygen supply unit 10A in the humidification process, the moisture separation performance does not decrease. In other words, in the moisture separation process, moisture is efficiently separated from the exhaust gas with a simple structure that only requires the exhaust gas to pass through the moisture separation unit, so it is possible to miniaturize the entire carbon dioxide separation device without requiring a large amount of power.

[0048] [Second Embodiment] Next, another embodiment of the carbon dioxide separation apparatus according to the present invention will be described. In the embodiments described below, parts having the same function as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions are omitted.

[0049] Figure 4 is a schematic diagram showing a second embodiment of the carbon dioxide separation apparatus according to the present invention. The combustion unit 12 of this embodiment is characterized by having a circulation line (piping) 22D for exhaust gas G5. This circulation line 22D for exhaust gas G5 is arranged to branch off from a connection line 22B installed between the combustion unit 12 and the moisture separation unit 15. A portion of the exhaust gas G5 G5-1 that has passed through the dehumidifier 40 is circulated to the combustion furnace 12A. Here, the exhaust gas G5 that is not circulated is supplied to the moisture separation unit 15. Thus, as shown in Figure 1B, the circulation line 22D may circulate inside the combustion section 12, or it may circulate outside the combustion section 12.

[0050] [Third Embodiment] Figure 5 is a schematic diagram showing a third embodiment of the carbon dioxide separation apparatus according to the present invention. Parts having the same function as those in the embodiments described above are given the same reference numerals, and detailed descriptions are omitted. In this embodiment, a carbon dioxide separation unit 42 is provided in the discharge line 24 to further concentrate the carbon dioxide in the dry exhaust gas G6 discharged from the moisture separation unit 15. This carbon dioxide separation unit 42 can be any device capable of concentrating carbon dioxide, such as a PSA system, VSA system, TSA system, etc.

[0051] By providing such a carbon dioxide separation unit 42, it becomes possible to achieve a carbon dioxide (CO2) concentration of 99% or more in the discharged dry exhaust gas G6.

[0052] [Fourth Embodiment] Figure 6 is a schematic diagram showing an example of use illustrating a fourth embodiment of the carbon dioxide separation apparatus described above. Parts having the same function as those in the above embodiment are given the same reference numerals, and detailed descriptions are omitted. As shown in Figure 6, the fourth embodiment shows an example in which the combustion section 12 of the carbon dioxide separation device described above is incorporated into the combustion section of the hydrogen production device 50. The hydrogen production apparatus 50 for generating hydrogen generates hydrogen at a high temperature (inside the combustion furnace), and to heat the combustion furnace 12A, it is possible to use an oxygen combustion method that introduces oxygen and fuel, as in the embodiment described above. For this reason, such a hydrogen production apparatus can incorporate the carbon dioxide separation apparatus described above.

[0053] The following describes the general structure of such an example of use. As shown in Figure 6, the hydrogen production apparatus 50 includes a compressor 52 for compressing the raw material gas (hydrocarbon fuel) 51, a desulfurizer 53, a reformer 54, a transformer 55, and hydrogen PSA 56.

[0054] The desulfurizer 53 has the function of removing sulfur components contained in the raw material gas as an odorant. However, the desulfurizer 53 does not need to be installed when using raw material gas that does not contain sulfur components.

[0055] The reformer 54 has the function of reforming the raw material gas to produce reformed gases such as hydrogen and carbon monoxide by adding water vapor (or pure water) to the raw material gas and bringing it into contact with a reforming catalyst at a high temperature (for example, 650°C to 900°C), and is housed inside the combustion furnace (oxygen combustion furnace) 12A. The reformer 54 is burned using the raw material gas and off-gas from hydrogen PSA 56 as fuel gases, together with oxygen supplied from the oxygen supply unit 10A of the carbon dioxide separation device 1.

[0056] The transformer 55 has the function of reacting carbon monoxide in the reformed gas sent from the reformer 54 with water vapor to produce even more hydrogen. In this transformer 55, depending on the reaction temperature, for example, from 200°C to 500°C, catalysts such as Fe-Cr, Cu-Zn, or Pt are used.

[0057] Hydrogen PSA56 uses an adsorbent to adsorb gases other than hydrogen, such as carbon monoxide, carbon dioxide, methane, and water vapor. This allows for the separation of hydrogen from the reformed gas supplied from the transformer 55, ultimately yielding hydrogen 60 concentrated to approximately 99.999%. The off-gas OG generated by this hydrogen PSA56 may also be used as fuel for heating the reformer 54.

[0058] As described above, when a combustion furnace 12A using the oxygen combustion method is incorporated into the reformer 54 of the hydrogen production apparatus 50, applying the carbon dioxide separation apparatus 1 described above makes it possible to efficiently separate and recover carbon dioxide.

[0059] The carbon dioxide separation apparatus according to the present invention has been described above, but the present invention is sufficient as long as it can implement at least the following carbon dioxide separation method, and the components of the carbon dioxide separation apparatus can be modified as appropriate. In other words, the system should include a combustion step in which combustion takes place in the combustion section 12 using oxygen supplied from the oxygen supply section 10A and supplied fuel, a drying step in which the exhaust gas discharged in the combustion step is passed through the moisture separation section 15 to separate moisture, and a humidification step in which oxygen supplied from the oxygen supply section is passed through the moisture separation section to humidify the system.

[0060] Furthermore, the present invention can be applied to various gas separation devices that supply oxygen and fuel to perform combustion and separate carbon dioxide from exhaust gas. For example, it can be applied to the gas separation device described in Japanese Patent Application No. 2023-168972 proposed by the present inventor.

[0061] [Fifth Embodiment] Figure 7 is a schematic diagram showing a fifth embodiment of the carbon dioxide separation apparatus according to the present invention. Parts having the same function as those in the above embodiment are given the same reference numerals, and detailed descriptions are omitted. As shown in Figure 7, the carbon dioxide separation apparatus 1 of the fifth embodiment reverses the installation of the fuel supply unit 10B and the oxygen supply unit 10A compared to the carbon dioxide separation apparatus 1 of Figure 1. That is, when the first gas is a gas containing hydrogen atoms (fuel F), the second gas is a gas containing oxygen atoms.

[0062] As shown in Figure 7, the carbon dioxide separation apparatus 1 of the fifth embodiment includes a fuel supply unit 10B which is a first gas supply unit that supplies fuel F, an oxygen supply unit 10A which is a second gas supply unit that supplies oxygen O2, a combustion unit 12 which is a reaction unit that is equipped with a combustion furnace 12A which is a reaction furnace to which oxygen from the oxygen supply unit 10A is supplied and reacts (combustion) with the fuel, and a dehumidifier 40 which separates moisture from the combustion gas G4 containing moisture and carbon dioxide produced in the combustion furnace 12A, and a moisture separation unit 15 which is introduced to exhaust gas G5 which is a dehumidified product gas discharged from the combustion unit 12 and separates moisture remaining in the exhaust gas G5.

[0063] The moisture separation unit 15 is located between the fuel supply unit 10B and the combustion furnace 12A and includes a fuel inlet (first gas inlet) 15e for introducing dry first gas (fuel) supplied from the first gas (fuel) supply unit, a fuel outlet (first gas outlet) 15f for discharging the first gas (fuel) containing moisture to the reaction unit 12A, an exhaust gas inlet 15c for introducing exhaust gas G5 containing at least moisture and carbon dioxide exhausted from the reaction unit 12A, and an exhaust gas outlet 15d for discharging the dry exhaust gas from which moisture has been removed.

[0064] Here, regarding the dry state of the supplied fuel F, it is preferable that it has a dryness level of -50°C or lower so that the adsorbent provided in the moisture separation unit 15 can be efficiently dried. The effects of the moisture separation unit 15 are the same as in Embodiment 1. According to this embodiment, it is possible to efficiently separate moisture from exhaust gas containing carbon dioxide. [Industrial applicability]

[0065] The present invention is widely applicable to carbon dioxide separation apparatuses and carbon dioxide separation methods in general. [Explanation of Symbols]

[0066] 1. Carbon dioxide separation apparatus 10A Oxygen Supply Unit 10B Fuel supply section 12 Combustion section (reaction section) 12A Combustion furnace (reaction furnace) 15 Moisture separation section 15A 1st dehumidification tower 15B 2nd dehumidification tower 15a Oxygen inlet (first gas inlet) 15b Oxygen exhaust port (1st gas exhaust port) 15c Exhaust gas inlet (generated gas inlet) 15d Exhaust gas outlet (generated gas outlet) 15e Fuel Inlet (First Gas Inlet) 15f Fuel outlet (1st gas outlet) 20C combustion gas G4 circulation line 20D Exhaust gas G6 circulation line 40 Dehumidifier (moisture separation section) 42 Carbon dioxide separation section 50 Hydrogen production equipment G1 Air G2 Dry Oxygen G3 Oxygen containing moisture (first gas) G4 Combustion gas (product gas) G5 Exhaust gas (generated gas) G6 Dry exhaust gas (dry product gas (CO2)) OG Off-gas

Claims

1. A first gas supply unit that supplies the first drying gas, The second gas supply unit supplies the second gas, A combustion unit comprising: a combustion furnace to which a first gas from the first gas supply unit is supplied and which reacts with the second gas; and a dehumidifier for separating moisture from the product gas containing moisture and carbon dioxide produced in the combustion furnace; The system includes a moisture separation unit into which dehumidified gas discharged from the dehumidifier of the combustion unit is introduced, and moisture remaining in the dehumidified gas is separated by an adsorbent. The moisture separation unit is provided between the first gas supply unit and the combustion furnace, and includes a first gas inlet for introducing the first dry gas supplied from the first gas supply unit, A first gas outlet for discharging a first gas containing moisture into the combustion furnace, A product gas inlet for introducing dehumidified product gas containing at least moisture and carbon dioxide exhausted from the combustion furnace, A gas outlet for discharging the dry gas from which moisture has been removed, It is equipped with, A connection line for introducing the drying first gas from the first gas supply unit into the first gas inlet 15a, A connection line for introducing the first gas, from which the adsorbent has been dehumidified, into the combustion furnace from the first gas outlet, The dehumidifier is equipped with a connecting line that introduces the dehumidifying generated gas 5) containing at least moisture and carbon dioxide, exhausted from the dehumidifier, into the generated gas inlet, The dry first gas is either oxygen or fuel. A carbon dioxide separation apparatus characterized by the following features.

2. The aforementioned moisture separation unit comprises a plurality of adsorption units, each equipped with an adsorbent that adsorbs moisture. The carbon dioxide separation apparatus according to claim 1, characterized in that each adsorption unit comprises the first gas inlet, the first gas outlet, the generated gas inlet, and the generated gas outlet.

3. The carbon dioxide separation apparatus according to claim 1, characterized in that it includes a circulation line for introducing a portion of the combustion gas discharged from the combustion furnace into the combustion furnace.

4. The carbon dioxide separation apparatus according to claim 1, characterized in that it includes a circulation line for introducing a portion of the exhaust gas that has passed through the dehumidifier into the combustion furnace.

5. The carbon dioxide separation apparatus according to claim 1, further comprising a carbon dioxide separation unit for increasing the concentration of carbon dioxide from the dry product gas containing carbon dioxide discharged from the moisture separation unit.

6. The carbon dioxide separation apparatus according to claim 1, characterized in that the combustion furnace is incorporated into a hydrogen production apparatus.

7. Using the carbon dioxide separation apparatus described in Claim 1, A combustion process in which a dry first gas supplied from a first gas supply unit and a second gas supplied from a second gas supply unit are used to perform combustion in a combustion unit, A drying step is performed by passing the generated gas discharged in the combustion step through a moisture separation section to separate the moisture, A humidification step is performed by passing the first drying gas through a moisture separation section to humidify it. A method for separating carbon dioxide, characterized by having [a certain feature].

8. The carbon dioxide separation method according to claim 7, characterized in that the moisture separation step alternately introduces the drying first gas and the reaction gas into each of a plurality of adsorption units equipped with an adsorbent for adsorbing moisture.

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