Carbon dioxide recovery system and carbon dioxide recovery device

Abstract

Provided is a carbon dioxide recovery system including: a plurality of recovery devices 1 for recovering carbon dioxide; and a conversion device 2 for converting carbon dioxide, wherein the recovery devices 1 each include an air introduction part 11 for taking in air, a concentration part 12 for concentrating carbon dioxide in the taken-in air, and a conveyance part 15 for conveying a concentrated gas of carbon dioxide concentrated by the concentration part or a concentrated gas of carbon dioxide conveyed from another recovery device via a conveyance path to the conversion device or another recovery device via another conveyance path.

Description

Carbon dioxide capture system and carbon dioxide capture device

[0001] The present disclosure relates to carbon dioxide capture systems and carbon dioxide capture devices.

[0002] To solve the problem of global warming, there is a social demand for efforts to reduce the concentration of carbon dioxide in the atmosphere. In particular, technologies that convert carbon dioxide into other products and use those products as renewable fuels, or technologies that use carbon dioxide as a building material for structures and achieve long-term fixation, are being widely researched (Non-Patent Document 1). As methods for preparing carbon dioxide for conversion, methods using carbon dioxide emitted from industrial plants and methods of capturing carbon dioxide from the atmosphere are being considered. Furthermore, Non-Patent Document 2 states that the concentration of carbon dioxide in the atmosphere is approximately 0.1 ton / m per year. 2 The amount of carbon dioxide converted is presented.

[0003] Kato N., et al. "A large-sized cell for solar-driven CO2 conversion with a solar-to-formate conversion efficiency of 7.2%," Joule, vol. 5, issue 3, pp. 687-705, Mar. 2021. "Toyota Central R&D Labs. achieves 7.2% efficiency with artificial photosynthesis producing formic acid, aiming for practical application by 2030," Nikkei XTech, April 23, 2021. Keiji Aihara, "On the three-dimensional distribution of carbon dioxide concentrations in Kanagawa Prefecture," [online], Internet: <https: / / www.pref.kanagawa.jp / documents / 3463 / kensi2003-8.pdf>

[0004] Carbon dioxide conversion requires not only carbon dioxide but also water, electricity, etc., and the products produced from carbon dioxide can be toxic, so strict management is desirable. For these reasons, it is an efficient method to collect a certain amount of carbon dioxide in one place and convert it.

[0005] On the other hand, when capturing carbon dioxide from the atmosphere, a large amount of air must be used for capture, since the concentration of carbon dioxide in the atmosphere is very low at 0.03 to 0.04%. In comparison, the amount of carbon dioxide consumed in the conversion of carbon dioxide is large. In addition, the concentration of carbon dioxide in the atmosphere generally varies locally depending on the source of the carbon dioxide.

[0006] Therefore, if carbon dioxide is captured at one location and the converted carbon dioxide is removed and then released into the atmosphere, the carbon dioxide concentration at that location will decrease, and there is a risk that the efficiency of carbon dioxide capture will deteriorate thereafter (Non-Patent Document 3).

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a technology for efficiently recovering carbon dioxide.

[0008] In order to achieve the above-mentioned object, one aspect of the present disclosure is a carbon dioxide capture system comprising a plurality of capture devices that capture carbon dioxide and a conversion device that converts the carbon dioxide, wherein the capture devices comprise an air inlet section that takes in air, a concentration section that concentrates the carbon dioxide in the taken-in air, and a transport section that transports the carbon dioxide enriched gas concentrated by the concentration section, or the carbon dioxide enriched gas transported from another capture device via a transport path, to the conversion devices or another other capture device via another transport path.

[0009] One aspect of the present disclosure is a carbon dioxide capture device comprising: an air inlet section that takes in air; a concentration section that concentrates carbon dioxide in the taken-in air; and a transport section that transports, via another transport path, the carbon dioxide enriched gas concentrated by the concentration section or the carbon dioxide enriched gas transported from another capture device via the other transport path, to a conversion device that converts carbon dioxide or another other capture device.

[0010] According to the present disclosure, it is possible to provide a technology for efficiently recovering carbon dioxide.

[0011] FIG. 1 is an example of the overall configuration of a carbon dioxide capture system according to a first embodiment. FIG. 2 is a configuration diagram showing an example of a capture device according to the first embodiment. FIG. 3 is a configuration diagram showing an example of a conversion device according to the first embodiment. FIG. 4 is a configuration diagram showing an example of a capture device according to a second embodiment. FIG. 5 is a configuration diagram showing an example of a capture device according to a third embodiment. FIG. 6 is a configuration diagram showing an example of a capture device according to a fourth embodiment.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] 1 shows an example of the overall configuration of a carbon dioxide capture system according to this embodiment. The illustrated system includes a plurality of capture devices 1, a conversion device 2, and a carbon dioxide transport path 3. Hereinafter, carbon dioxide will also be referred to as "CO2."

[0014] The transport path 3 is a pipe that connects the recovery device 1 and the conversion device 2, or connects the recovery devices 1 to each other. A CO2-enriched gas, which will be described later, is transported through the transport path 3. The transport path 3 can be configured using, for example, a rubber tube, a wire that serves as a tension member, or the like.

[0015] 2 shows an example of the configuration of a capture device 1 (carbon dioxide capture device) according to this embodiment. The capture device 1 captures carbon dioxide. The illustrated capture device 1 includes an air introduction section 11, a CO2 concentration section 12 (concentration section), and a transport section 15. The capture device 1 may also include an exhaust section 13 and a storage section 14.

[0016] The air introduction section 11 takes in air. That is, the air introduction section 11 introduces outside air around the recovery device 1. The air introduction section 11 can be configured using, for example, an air supply fan and a filter.

[0017] The CO2 concentrating unit 12 concentrates carbon dioxide in the air taken in by the air inlet 11. That is, the CO2 concentrating unit 12 extracts CO2-enriched gas in which carbon dioxide is concentrated from the introduced outside air. The CO2 concentrating unit 12 can be configured using, for example, a CO2 separation membrane.

[0018] The exhaust unit 13 exhausts air other than the CO2-enriched gas. Specifically, the exhaust unit 13 exhausts the remaining gas after removing the CO2-enriched gas from the introduced outside air. The exhaust unit 13 can be configured using, for example, an air supply fan. The storage unit 14 stores the CO2-enriched gas concentrated by the CO2 concentration unit 12. The storage unit 14 may be any container capable of storing CO2-enriched gas.

[0019] The transport section 15 transports (sends) the CO2-enriched gas concentrated by the CO2 concentration section 12 or the CO2-enriched gas transported from another recovery device via the transport path 3A to the conversion device 2 or another recovery device via the transport path 3B (another transport path).

[0020] For example, the transport unit 15 may send the CO2-enriched gas in the storage unit 14 to the transport path 3B. Alternatively, the transport unit 15 may send the CO2-enriched gas that has been concentrated in another capture device and has been transported via the transport path 3A to the transport path 3B. Alternatively, the transport unit 15 may combine the CO2-enriched gas in the storage unit 14 with the CO2-enriched gas from another capture device and has been transported via the transport path 3A, and send them to the transport path 3B. The transport path 3B is connected to the conversion device 2 or another capture device.

[0021] The other recovery device connected to the transport path 3A is assumed to be a recovery device located farther from the converter 2 than the recovery device 1. Furthermore, if the device connected to the transport path 3B is another recovery device, the other recovery device is assumed to be a recovery device located closer to the converter 2 than the recovery device 1. In this way, the recovery device of this embodiment not only recovers carbon dioxide but also serves as a relay device for carbon dioxide (CO2-enriched gas). The transport unit 15 can be configured using, for example, an air supply fan.

[0022] A commercial power service may be used as a power source (not shown) for operating the air introduction section 11, the exhaust section 13, and the transport section 15. Furthermore, as will be described in a second embodiment below, a solar power generation section or a wind power generation section may be provided as a power source. Furthermore, a combination of commercial power service, solar power generation, and wind power generation may also be used. The illustrated configuration of the recovery device 1 is merely an example and is not intended to be limiting.

[0023] 3 shows an example of the configuration of the converter 2 of this embodiment. The converter 2 converts the carbon dioxide captured by the capture device 1. Specifically, the converter 2 converts the CO2-enriched gas delivered from the capture device 1 into other products. The illustrated converter 2 includes a feed section 21, a CO2 conversion section 22, and a storage section 23.

[0024] The carry-in unit 21 carries in the CO2-enriched gas transported from the capture device 1 via the transport path 3B. The carry-in unit 21 then sends out the taken-in enriched gas to the CO2 conversion unit 22. That is, the carry-in unit 21 transports the CO2-enriched gas captured by the capture device 1 to the CO2 conversion unit 22. The carry-in unit 21 can be configured using, for example, an air supply fan.

[0025] The CO2 conversion unit 22 converts the CO2-enriched gas taken in by the delivery unit 21 into other products (compounds, chemical substances, etc.). Specifically, the CO2 conversion unit 22 converts all or part of the carbon dioxide in the CO2-enriched gas into products that are other compounds. The CO2 conversion unit 22 converts carbon dioxide into other products using electrochemical methods, artificial photosynthesis using photocatalysts, methods using microorganisms, etc.

[0026] The storage unit 23 stores the product converted (produced) by the CO2 conversion unit 22. The storage unit 23 may be any container capable of storing the product.

[0027] As shown in Figure 1, in this embodiment, multiple capture devices 1 are connected to one conversion device 2, and the multiple capture devices 1 are distributed over a wide area, and the CO2-enriched gas generated in each capture device 1 is transported to the conversion device 2 via a transport path 3.

[0028] As mentioned above, according to the technology of Non-Patent Document 2, currently, the maximum load is 100 kg / m 2 It is expected that CO2 conversion will last for more than 10 years. The size of the CO2 conversion device is assumed to be installed in a building (10m x 10m = 100m 3Assuming a large-scale plant (such as a power station), this means that more than 10 tons of carbon dioxide can be converted per year. The more CO2 converted, the better, so it is desirable to secure an amount of CO2 that will allow the converter 2 to operate at full capacity. On the other hand, the CO2 content in the atmosphere is approximately 0.8 g / m 3 Therefore, to obtain more than 10 tons of carbon dioxide per year, we need at least about 1.2 × 10 8 m 3 / year = approx. 230m 3 / min atmosphere is required.

[0029] When CO2 conversion is performed using a combination of one capture device and one conversion device, the total capacity is 230m 3 The air volume is about 15m / min. 3 / min), the recovery equipment 1 will be large-scale and will require a large amount of power consumption. Furthermore, since CO2 will disappear from 70 cubic meters of air per day, if the equipment continues to operate, the CO2 concentration around the recovery equipment 1 will decrease, and it is thought that the amount of CO2 will become insufficient.

[0030] On the other hand, when the recovery device 1 is driven by solar cells or wind power generation, the air intake fan of the air introduction section 11 should have a wind volume of 1 m 3 / min or less. Therefore, to fully operate one conversion device 2, it is desirable to combine 230 or more capture devices 1. In other words, it is desirable for the carbon dioxide capture system to have 230 or more capture devices 1 for one conversion device 2.

[0031] In this case, the intake volume of one capture device per day is approximately 11 m 3 , and if the capture devices 1 are installed at sufficient intervals, the decrease in CO2 concentration can be sufficiently suppressed by atmospheric circulation due to wind, etc. When transporting CO2-enriched gas that has been concentrated from 400 ppm to 1% (10,000 ppm) in the atmosphere, the total volume of CO2-enriched gas transported from all 230 capture devices 1 to one conversion device 2 is 0.95 m 3 . 3 This is an amount that can be processed by an air supply fan driven by solar cells or wind power generation, and by miniaturizing the equipment of the recovery device 1 that performs the transport function along the way, it can be driven by solar cells or wind power generation.

[0032] As mentioned above, the amount of air introduced into the capture device 1 should be at least 11 m3 per day. Furthermore, to avoid a sudden drop in CO2 concentration, it is desirable to prepare at least 10 times the amount of air, so the amount of air to be prepared should be at least 24 m3. In other words, to maintain CO2 capture efficiency, it is desirable to install capture devices 1 at intervals of at least 24 m.

[0033] On the other hand, it is desirable to install the transport path 3 using an existing utility pole or the like. If the diameter of the pipe that will be the transport path 3 becomes larger, the force exerted by external forces such as wind force on existing facilities such as utility poles will increase. For this reason, it is desirable that the diameter of the pipe be the same as that of the power cable or communication cable installed on the utility pole. Therefore, it is desirable that the inner diameter of the pipe of the transport path 3 be 2.5 cm or less. Assuming that the capture device 1 generates CO2-enriched gas that is enriched to 1%, the amount of CO2 generated is 4.1 x 10 -3 m 3 If this is transported through a straight pipe with the smallest pressure loss, the pressure loss P [Pa] is expressed by the following formula:

[0034]

[0035] Here, Q is the air volume [m 3 / min], D is the inner diameter of the pipe [m], and L is the pipe length [m]. From the above, the pressure loss is at least about 9.4 L × 10 -3 [Pa]. In order to drive the air supply fan using solar cells or wind power generation, it is desirable to keep the static pressure of the air supply fan at 10 Pa (approximately 1 mmH2O, the level of a computer fan) or less. From the above, L is at most approximately 1.06 km, and it is expected that it will be difficult to supply air further than this when driven by solar cells or wind power generation. For this reason, when using solar cells or wind power generation as the power source, it is desirable that the interval between collection devices 1 be at most 1.06 km or less. For the above reasons, it is desirable that the installation interval between collection devices 1 be at least 24 m and no more than 1.06 km.

[0036] In this way, in this embodiment, a large number of capture devices 1 are connected to one converter 2, and the large number of capture devices 1 are distributed over a wide area. This has the advantages of ensuring a sufficient amount of CO2, miniaturizing the capture device 1 equipment, and enabling it to be powered by solar cells or wind power.

[0037] In addition, for example, the capture devices 1 may be installed at a high density in places with high CO2 concentrations, such as industrial areas or places with heavy automobile traffic, and at a low density in places with low CO2 concentrations, such as rural areas.

[0038] Second Embodiment Fig. 4 shows an example of the configuration of a recovery device 1A driven by solar power generation or wind power generation. The recovery device 1A of this embodiment differs from the recovery device 1 shown in Fig. 2 in that it includes a power supply unit 19, but is otherwise similar to the recovery device 1.

[0039] The power supply unit 19 has a solar power generation unit (e.g., a solar cell) or a wind power generation unit. The power supply unit 19 may also include a solar power generation unit and a wind power generation unit. In this embodiment, the air introduction unit 11, the exhaust unit 13, and the conveying unit 15 are driven using the electromotive force of the power supply unit 19. In this embodiment, no special control is performed on the air introduction unit 11 and the conveying unit 15, and the air introduction unit 11 and the conveying unit 15 are driven in response to the electromotive force of solar power generation or wind power generation.

[0040] 5 shows a configuration example of a recovery device 1B that controls the air introduction section 11 and the transport section 15. The recovery device 1B of this embodiment differs from the recovery device 1 shown in FIG. 2 in that it includes a control section 16 and a communication section 17, but is otherwise similar to the recovery device 1.

[0041] The communication unit 17 communicates with an external device (such as a server) provided at a location remote from the recovery device 1 B. The external device (not shown) is a device that provides meteorological data such as CO 2 concentration.

[0042] The control unit 16 controls the air introduction unit 11 and the transport unit 15 based on weather data provided by an external device. Specifically, the control unit 16 uses the communication unit 17 to obtain the CO2 concentration in the area where the capture device 1B is installed from the external device. The control unit 16 then controls the processing capabilities (e.g., the rotation speed and torque of the air supply fan) of the air introduction unit 11 and the transport unit 15 based on the obtained CO2 concentration. That is, the control unit 16 controls the CO2 capture capacity of the capture device 1B based on the ambient CO2 concentration. For example, the control unit 16 may increase the processing capabilities of the air introduction unit 11 and the transport unit 15 when the CO2 concentration is greater than a first threshold, and decrease the processing capabilities of the air introduction unit 11 and the transport unit 15 when the CO2 concentration is less than a second threshold.

[0043] A general-purpose computer system can be used for the control unit 16. The computer system may include a CPU (Central Processing Unit, or processor), memory, storage (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device, an input device, an output device, and the like. In this computer system, the CPU executes a predetermined program loaded into the memory, thereby realizing each function of the control unit 16. The program for the control unit 16 can be stored in a computer-readable recording medium such as an HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or can be distributed via a network. The computer-readable recording medium is, for example, a non-transitory recording medium.

[0044] 6 shows another example of the configuration of a recovery device 1C that controls the air introduction unit 11 and the transport unit 15. The recovery device 1C of this embodiment differs from the recovery device 1 shown in FIG. 2 in that it includes a control unit 16 and a CO2 concentration detection unit 18, but is otherwise similar to the recovery device 1.

[0045] The CO2 concentration detection unit 18 detects the CO2 concentration in the area where the capture device 1C is installed and sends the detected CO2 concentration to the control unit 16. The control unit 16 controls the processing capacity of the air introduction unit 11 and the transport unit 15 according to the CO2 concentration detected by the CO2 concentration detection unit 18. That is, the control unit 16 controls the CO2 capture capacity of the capture device 1C according to the ambient CO2 concentration. The control by the control unit 16 is similar to that of the control unit 16 in the third embodiment.

[0046] The carbon dioxide capture system of the above-described embodiment includes a plurality of capture devices that capture carbon dioxide and a conversion device that converts carbon dioxide, and the capture devices include an air inlet that takes in air, a concentration unit that concentrates the carbon dioxide in the taken-in air, and a transport unit that transports the carbon dioxide-enriched gas concentrated by the concentration unit or the carbon dioxide-enriched gas transported from another capture device via a transport path to the conversion device or another other capture device via another transport path. The conversion device may also include a transport unit that transports the concentrated gas transported from the plurality of capture devices, and a conversion unit that converts the carbon dioxide in the transported concentrated gas into another product.

[0047] In this embodiment, carbon dioxide can be efficiently captured by supplying the carbon dioxide captured using a plurality of conversion devices to a conversion device. Furthermore, in this embodiment, it is possible to achieve both efficient carbon dioxide capture and efficient carbon dioxide conversion.

[0048] Furthermore, in this embodiment, since multiple capture devices are used to capture carbon dioxide, each capture device can capture an appropriate amount of carbon dioxide so that the CO2 concentration in the air does not decrease rapidly. For example, if carbon dioxide capture and conversion were carried out in one location, the carbon dioxide concentration at that location could decrease, which could result in a decrease in carbon dioxide capture efficiency. However, in this embodiment, by capturing carbon dioxide using multiple capture devices, it is possible to avoid a decrease in carbon dioxide capture efficiency.

[0049] The capture devices of the third and fourth embodiments are also equipped with a control unit. Because the air around the capture device is replaced by atmospheric air flow, the control unit appropriately adjusts the amount of CO2 captured according to the ambient CO2 concentration, thereby preventing a drastic decrease in CO2 concentration and maintaining carbon dioxide capture efficiency.

[0050] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0051] 1: Recovery device (carbon dioxide recovery device) 11: Air introduction section 12: CO2 concentration section (concentration section) 13: Exhaust section 14: Storage section 15: Transport section 2: Converter (carbon dioxide conversion device) 21: Carry-in section 22: Converter section 23: Storage section 3: Transport path

Claims

1. A carbon dioxide capture system comprising a plurality of capture devices that capture carbon dioxide and a conversion device that converts the carbon dioxide, wherein the capture devices comprise: an air inlet section that takes in air; a concentration section that concentrates the carbon dioxide in the taken-in air; and a transport section that transports the carbon dioxide concentrated gas concentrated by the concentration section, or the carbon dioxide concentrated gas transported from another capture device via a transport path, to the conversion devices or another other capture device via another transport path.

2. The carbon dioxide capture system according to claim 1, wherein the conversion device comprises: an input section for inputting the concentrated gas transported from the plurality of capture devices; and a conversion section for converting the carbon dioxide in the input concentrated gas into other products.

3. A carbon dioxide capture system as described in claim 1, wherein the capture device is equipped with a solar power generation unit or a wind power generation unit, and the air introduction unit and the conveying unit are driven by electricity generated by the solar power generation unit or the wind power generation unit.

4. A carbon dioxide recovery device comprising: an air inlet section that takes in air; a concentration section that concentrates the carbon dioxide in the taken-in air; and a transport section that transports the carbon dioxide concentrated gas concentrated by the concentration section or the carbon dioxide concentrated gas transported from another recovery device via a transport path to a conversion device that converts carbon dioxide or another other recovery device via another transport path.

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