CO2 capture system

Abstract

CO2 capture system (1), comprising: a CO2 capture device (4, 31) which separates and captures CO2 from the air; a plurality of buildings (2); and a flow path (3) which feeds exhaust gas emitted from the building (2) to the CO2 capture device (4, 31) in order to capture the CO2 from the exhaust gas by the CO2 capture device (4, 31), characterized by: a flow rate controller (7) which regulates the flow rate of the exhaust gas flowing from the building (2) towards the CO2 capture device (4, 31) through the flow path (3); and a control unit (8) which controls the flow rate controller (7) to regulate the flow rate of the exhaust gas.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese Patent Application No. 2021-164015 (JP 2021-164015 A), filed with the Japan Patent Office on October 5, 2021. BACKGROUNDField of the invention

[0002] Embodiments of the present invention relate to the field of a CO2 capture system that captures CO2 released into the atmosphere and stores the captured CO2. Discussion of the state of the art

[0003] JP 2011-038667 A describes an oxygen combustion system used, for example, in a thermal power plant, and an operating method thereof. The oxygen combustion system described in JP 2011-038667 A comprises: a combustion device for combusting oxygen, combustion exhaust gas, and fuel; a carbon dioxide recovery device for recovering carbon dioxide from the generated combustion exhaust gas; a pipeline for transferring carbon dioxide to another location; a carbon dioxide discharge line for discharging carbon dioxide to the pipeline; and a carbon dioxide intake line for transferring carbon dioxide from the pipeline to the oxygen combustion system. Furthermore, on-off valves are arranged on the carbon dioxide discharge line and the carbon dioxide intake line.According to the teachings of JP 2011-038667 A, the on-off valves are manipulated according to the operating conditions of the oxygen combustion system and the oxygen concentration in the oxygen combustion system. Therefore, according to the teachings of JP 2011-038667 A, the start-up time of the oxygen combustion system can be reduced, and the amount of carbon dioxide released into the environment of the oxygen combustion system can be reduced.

[0004] As described above, the teachings of JP 2011-038667 A can be applied to a thermal power plant that generates electricity using a steam turbine. In a power plant of this type, to reduce CO2 emissions, CO2 resulting from the combustion of fuel and air (i.e., oxygen) is collected by a CO2 recovery device and stored in a reservoir.

[0005] CO2, as one of the factors contributing to global warming, is also emitted by manufacturing facilities, homes, shops, restaurants, factories, offices, and so on. To prevent global warming, CO2 emissions from these buildings can be reduced by transmitting the air emitted by these buildings to, for example, the carbon dioxide recovery device described in JP 2011-038667 A, thereby separating the CO2 from the air to collect CO2. However, CO2 emissions from these buildings vary throughout the day and seasons. Therefore, if the emission (i.e., air) from these buildings is fed to the carbon dioxide recovery device in a constant manner, CO2 cannot be captured efficiently.

[0006] Document DE 10 2022 120 267 A1 discloses a method and system for appropriately using CO2 captured from the atmosphere as an agricultural fertilizer and as a fuel for electric power generation. Specifically, the recycling method comprises collecting information regarding the demand for the CO2 to be used as a fertilizer and the demand for the CO2 to be used as a fuel; calculating a ratio between an amount of CO2 to be used as a fertilizer and an amount of CO2 to be used as a fuel based on the collected information; and then using the CO2 as a fertilizer and as a fuel based on the calculated ratio.

[0007] Furthermore, WO 2018 / 103896 A1 discloses a method for improving air quality in a building, wherein an oxygen-containing gaseous fluid stream is supplied to the building and distributed within the building. In particular, the oxygen-containing gaseous fluid stream is formed at least partially using an oxygen-containing fluid-air product stored in a container, removed from the container, and air is extracted from the building, treated, and returned to the building, wherein the treatment includes adsorptive removal of carbon dioxide. A corresponding plant and a corresponding system are also disclosed. SUMMARY

[0008] Aspects of the embodiments of the present invention have been designed with the above technical problems in mind, and it is therefore an object of the present invention to provide a CO2 capture system for efficiently capturing CO2 from emissions emitted by buildings and houses.

[0009] According to the present invention, there is provided a CO2 capture system comprising: a CO2 capture device that captures and separates CO2 from the air; a plurality of buildings; and a flow path that transmits exhaust gas discharged from the building to the CO2 capture device, to capture the CO2 from the exhaust gas by means of the CO2 capture device. To achieve the above-stated object, according to the present invention, the CO2 capture system is provided with: a flow rate regulator that regulates a flow rate of the exhaust gas flowing from the building toward the CO2 capture device through the flow path; and a control unit that controls the flow rate regulator to regulate the flow rate of the exhaust gas.

[0010] In one non-limiting embodiment, the control unit may be configured to: collect information regarding a concentration of CO2 in the exhaust gas emitted from the building; and control the flow rate controller based on the collected information.

[0011] In one non-limiting embodiment, the CO2 capture system may further include a detector that collects behavioral data from building occupants, including the number of people entering and exiting the building and the behavior of the people in the building. Furthermore, the control unit may be further configured to: receive the behavioral data of the building occupants; and regulate the flow rate of the exhaust gas based on the behavioral data.

[0012] In one non-limiting embodiment, the control unit may be further configured to increase the flow rate of the exhaust gas with an increase in the number of occupants of the building.

[0013] In one non-limiting embodiment, the control unit may be further configured to increase the flow rate of the exhaust gas during a period in which the number of residents of the building is high compared to a period in which the number of residents of the building is small.

[0014] In one non-limiting embodiment, the control unit may be further configured to stop supplying the exhaust gas from the building to the CO2 capture device when none is in the building.

[0015] In one non-limiting embodiment, the control unit may be further configured to: estimate the concentration of CO2 in the exhaust gas emitted by the building based on the behavioral data of the building's occupants; and increase the flow rate of the exhaust gas with an increase in the concentration of CO2 in the exhaust gas.

[0016] In one non-limiting embodiment, the CO2 capture system may further include a CO2 sensor that detects a concentration of CO2 in the exhaust gas emitted by the building. Furthermore, the control unit may be further configured to increase the flow rate of the exhaust gas with an increase in the concentration of CO2 in the exhaust gas detected by the CO2 sensor.

[0017] In one non-limiting embodiment, the flow rate regulator may comprise a valve disposed between the building and the CO2 capture device, and the control unit may be further configured to regulate the flow rate of the exhaust gas by actuating or manipulating the valve.

[0018] In one non-limiting embodiment, the flow rate regulator may comprise a fan disposed between the building and the CO2 capture device. Furthermore, the control unit may be further configured to regulate the flow rate of the exhaust gas by controlling a blast of wind generated by the fan.

[0019] In a smart city, CO2 is emitted not only from cooking appliances and heating systems in buildings, but also from the breathing of occupants in the buildings. CO2 contained in the exhaust gases emitted by buildings is captured by the CO2 capture system. However, CO2 emissions from buildings vary according to the time of day and season. Therefore, if the exhaust gas emitted by buildings is fed to the CO2 capture device at a constant rate, CO2 may not be captured efficiently. For example, if the concentration of CO2 in the exhaust gas is low, the amount of CO2 captured by the CO2 capture device would be reduced relative to the energy consumed to operate the CO2 capture device.To avoid such a disadvantage, according to the exemplary embodiment of the present invention, the flow rate regulator is arranged between each of the buildings and the CO2 capture device to regulate a flow rate of the exhaust gas flowing from the building toward the CO2 capture device. Therefore, according to the exemplary embodiment of the present invention, the flow rate of the exhaust gas delivered to the CO2 capture device can be adjusted according to, for example, a concentration of CO2 in the exhaust gas.

[0020] For this purpose, the control unit collects information regarding the concentration of CO2 contained in the exhaust gas and regulates the flow rate of the exhaust gas transmitted to the CO2 capture device based on the collected information. For example, to obtain the concentration of CO2 in the exhaust gas emitted by the building, the control unit collects information regarding the number of occupants of the building. Alternatively, the concentration of CO2 in the exhaust gas can also be directly detected by the CO2 sensor. Therefore, when the concentration of CO2 in the exhaust gas is low, the flow rate of the exhaust gas transmitted to the CO2 capture device can be reduced based on the collected information.

[0021] As described, the CO2 capture system according to the exemplary embodiment of the present invention includes the detector including a surveillance camera, a human detection sensor, a mobile terminal, etc. For example, in a case where the surveillance camera is adopted as the detector, the control unit 8 determines that the concentration of CO2 in the exhaust gas is high when the number of people in the building detected by the surveillance camera is high. On the other hand, in a case where the mobile terminal carried by the occupant of the building is adopted as the detector, the control unit 8 determines that the concentration of CO2 in the exhaust gas is high when the number of people carrying the mobile terminals in the building is high. Further, the number of people in the building can also be detected using a scheduling function of the mobile terminal.Therefore, according to the exemplary embodiment of the present invention, the flow rate of the exhaust gas transmitted to the CO2 trapping device can be regulated based on a detection value or a predicted value of the number of people in the building.

[0022] Specifically, according to the exemplary embodiment of the present invention, the flow rate of the exhaust gas delivered to the CO2 capture device increases with an increase in the number of people in the building. On the other hand, when no one is in the building, the control unit determines that the concentration of CO2 in the exhaust gas is low and stops delivering the exhaust gas to the CO2 capture device.

[0023] According to the exemplary embodiment of the present invention, the concentration of CO2 in the exhaust gas emitted from the building can also be directly detected by the CO2 sensor. For example, the flow rate of the exhaust gas transmitted to the CO2 capture device is increased with an increase in the concentration of CO2 in the exhaust gas detected by the CO2 sensor. On the other hand, when the concentration of CO2 in the exhaust gas detected by the CO2 sensor is less than a predetermined value, the control unit stops transmitting the exhaust gas to the CO2 capture device. Therefore, according to the exemplary embodiment of the present invention, the flow rate of the exhaust gas transmitted to the CO2 capture device can be controlled according to an actual concentration of CO2 in the exhaust gas directly detected by the CO2 sensor.

[0024] As also described, according to the exemplary embodiment of the present invention, the flow rate regulator includes the valve and the blower. Therefore, according to the exemplary embodiment of the present invention, the flow rate of the exhaust gas delivered to the CO2 capture device can be regulated by controlling an opening degree of the valve or a gust of wind generated by the blower.

[0025] Therefore, according to the exemplary embodiment of the present invention, the CO2 capture device can be operated efficiently, taking into account the concentration of CO2 in the exhaust gases emitted by the building. Therefore, according to the exemplary embodiment of the present invention, CO2 can be efficiently captured from the exhaust gases emitted by the buildings by means of the CO2 capture device. SHORT DESCRIPTION OF THE DRAWING

[0026] Features, aspects, and advantages of the exemplary embodiments of the present invention will be better understood with reference to the following description and accompanying drawings, which are not intended to limit the invention in any way. Fig. 1 is an illustrative drawing showing an example of a structure of the CO2 trapping system according to the present invention; Fig. 2 is an illustrative drawing showing another example of a structure of the CO2 trapping system according to the present invention; Fig. 3 is a flowchart showing an example of a routine for controlling a flow rate of an exhaust gas flowing toward a CO2 trapping device according to time; Fig. 4 is a flowchart showing another example of a routine or program for collecting behavioral data from occupants of a building, which is used to estimate a concentration of CO2 in the exhaust gas emitted by the building; Fig. 5 is a flowchart showing an example of a routine or program for directly detecting a concentration of CO2 in the exhaust gas emitted from the building; Fig. 6 is a flowchart showing an example of a routine for controlling a flow rate of the exhaust gas flowing toward the CO2 trapping device based on information about a concentration of CO2 in the exhaust gas; Fig. Figure 7 is a flowchart showing an example of a routine or program for storing data on the concentration of CO2 in a database; and Fig. 8 is a flowchart showing an example of a routine or program for controlling a flow rate of the exhaust gas flowing toward the CO2 trapping device based on the data stored in the database. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0027] Embodiments of the present invention will now be described with reference to the accompanying drawings. Note that the embodiments shown below are merely examples of the present invention, which are not intended to limit the scope of the present invention.

[0028] The CO2 capture system according to the exemplary embodiment of the present invention is configured to capture CO2 from exhaust gas emitted from houses and buildings in a predetermined area such as a smart city.

[0029] Referring to Fig. 1, an example of the CO2 capture system 1 according to the exemplary embodiment of the present invention is shown. As in Fig. As shown in Figure 1, in the CO2 capture system 1, air and exhaust gas emitted from a building 2 are conveyed to a CO2 capture device 4 through a flow path 3, and CO2 contained in the air and exhaust gas is separated and captured by the CO2 capture device 4. The CO2 captured by the CO2 capture device 4 is conveyed to a CO2 storage container 5. In Fig. 2, in particular, an example of intensively capturing the CO2 emitted from the buildings 2 in the smart city 6 by the CO2 capture device 4 is shown. The CO2 capture system 1 includes: a flow rate controller 7 that controls a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4; a control unit 8 that controls the flow rate controller 7; a CO2 sensor 9 that detects a concentration of CO2 contained in the exhaust gas emitted from the building 2; and a detector 10 that collects data on residents of the building 2, e.g., the number of residents in the building 2, the number of people entering and exiting the building 2, and the behavior of the people in the building 2.

[0030] The building 2 includes a house, a shop, a restaurant, a factory, a hospital, a warehouse, and so on, which are located in the smart city 6. For example, CO2 is emitted from a relatively small building 2, such as a house, a shop, an office, or the like, through the breathing of the occupants. In addition, CO2 is also emitted from heating systems and cooking appliances in the building 2. Therefore, the CO2 capture system 1 according to the exemplary embodiment of the present invention is configured to capture CO2 mainly from the small- or medium-sized buildings 2.

[0031] Outlets (not shown) of the buildings 2 are individually connected to an inlet (not shown) of the CO2 capture device 4 through the flow paths 3 as ventilation pipes, so that CO2-containing air is transmitted from the buildings 2 to the CO2 capture device 4 through the flow paths 3.

[0032] As described, the CO2 capture device 4 captures CO2 from the air and the exhaust gases transmitted from the buildings 2 through the flow paths 3. Furthermore, the CO2 capture device 4 is adapted to communicate with the control unit 8 via associated communication lines or public communication lines, so that data can be exchanged between the CO2 capture device 4 and the control unit 8.

[0033] For example, CO2 can be captured by the CO2 capture device 4 using the principles of physical adsorption, physical absorption, chemical adsorption, and cryogenic distillation, as disclosed in JP 2021-008852 A. Specifically, in a case of applying the physical adsorption method, CO2 is captured by bringing the exhaust gas into contact with a solid adsorbent such as activated carbon and zeolite, and then heating or depressurizing the solid adsorbent to desorb CO2 from the solid adsorbent.In a case of applying the physical absorption method, CO2 is captured by bringing the exhaust gas into contact with an absorption liquid such as methanol and ethanol to dissolve the CO2, whereby the CO2 is physically absorbed in the absorption liquid under high pressure at a low temperature, and then the absorption liquid is heated or expanded to collect the CO2 from the absorption liquid. In a case of applying the chemical adsorption method, CO2 is captured by bringing the exhaust gas into contact with an absorption liquid such as an amine to selectively dissolve the CO2, whereby the CO2 is chemically absorbed in the absorption liquid, and then the absorption liquid is heated to collect the CO2 from the absorption liquid. In a case of applying the refrigeration orIn the cryogenic distillation process, CO2 is captured by compressing and cooling the exhaust gas to liquefy the CO2 contained therein and selectively distilling the liquefied CO2 to collect the CO2.

[0034] The CO2 capture device 4 is connected to the CO2 storage tank 5 via a flow path 11 such that the CO2 captured by the CO2 capture device 4 is stored in the CO2 storage tank 5. Specifically, an outlet (not shown) of the CO2 storage device 4 is connected to an inlet (not shown) of the CO2 storage tank 5 via the flow path 11 as a pipe such that the CO2 captured by the CO2 capture device 4 is allowed to flow through the flow path 11 not only in the liquid phase but also in the gas phase, depending on the capture method. The CO2 storage tank 5 is also adapted to communicate with the storage unit 8 through the associated communication lines or public communication lines (both are not shown), so that the data can be exchanged between the CO2 storage tank 5 and the storage unit 8.For example, data regarding a CO2 reserve and available storage in the CO2 storage tank 5 are sent from the CO2 storage tank 5 to the storage unit 8. If the available storage in the CO2 storage tank 5 is small, the storage unit 8 restricts the input of exhaust gas from the buildings 2 to the CO2 capture device 4 by manipulating the flow rate regulator 7.

[0035] According to the exemplary embodiment of the present invention, the CO2 capture system 1 is applied to the smart city 6 in which the buildings 2 are located. The definition of "smart city" is defined by the Ministry of Land, Infrastructure, Transport and Tourism of the Japanese government as a sustainable city or region where various problems are solved through improvement management (e.g., planning, development, operation) using ICT (information and communication technology). In the smart city 6, CO2 emitted from the buildings is captured by the CO2 capture device 4, and the CO2 captured by the CO2 capture device 4 can be recycled into fuel. That is, CO2 can be circulated within the smart city to reduce CO2 emissions from the smart city 6.

[0036] For example, a valve mechanism such as a flow control valve and an on-off valve may be adopted as the flow rate regulator 7. In a case of using the flow control valves as the flow rate regulators 7, a flow rate of CO2 between each of the buildings 2 and the CO2 trapping device 4 is regulated according to opening degrees of the flow control valves. While in a case of using the on-off valves as the flow rate regulators 7, each of the flow paths 3 is selectively opened and closed by switching positions of the valve elements in the on-off valves. Furthermore, a damper disposed in, for example, a fan may also be used as the flow rate regulator 7 instead of the above-mentioned valves.Therefore, in the CO2 capture system 1 according to the exemplary embodiment of the present invention, flow rates of the exhaust gases transmitted from the buildings 2 to the CO2 capture device 4 can be regulated by the flow rate controllers 7.

[0037] Instead, a fan may also be adopted as the flow rate regulator 7. In this case, a flow rate of the exhaust gas flowing through the flow path 3 toward the CO2 capture device 4 is changed according to a gust of wind generated by the fan. In the CO2 capture system 1, both valves and fans may also be used together to serve as the flow rate regulators 7. The flow rate regulators 7 are also adapted to communicate with the control unit 8 via the associated communication lines or public communication lines, so that data can be exchanged between each of the flow rate regulators 7 and the control unit 8.

[0038] Specifically, the control unit 8, as a main controller of the CO2 capture system 1, is an electronic control unit including a microcomputer or a server computer. For example, the control unit 8 controls the flow rate controllers 7, thereby regulating the flow rates of CO2 transmitted from the buildings 2 to the CO2 capture device 4. To this end, the control unit 8 is connected to an external server and websites on the Internet via dedicated communication lines or public communication lines (both are not shown). Furthermore, various types of data collected by, for example, the CO2 sensor 9 and the detector 10 are transmitted to the control unit 8.

[0039] The CO2 sensor 9 directly detects a concentration of CO2 in the exhaust gas emitted by the building 2. For this purpose, the CO2 sensor 9 can be arranged, for example, near the outlet of the building 2 and in the flow path 3 between the building 2 and the flow rate controller 7.

[0040] The detector 10 collects data regarding the number of people entering and exiting the building 2 and data regarding the behavior of the people in the building 2. For example, a surveillance camera (or security camera) and a human detection sensor can be adopted as the detector 10 to monitor the people entering and exiting the building 2. Based on the number of people detected by the detector 10, the control unit 8 estimates a concentration of CO2 in the exhaust gas emitted from the building 2. Specifically, if the number of people in the building 2 is large, the control unit 8 estimates that the concentration of CO2 in the exhaust gas is high. Instead, a mobile terminal (not shown) such as a mobile phone, a computer, an electronic data book, or the like, which is carried by the people entering and exiting the building 2, can also be adopted as the detector 10.In this case, for example, the detector 10 collects data regarding the number of people entering or leaving the building 2 and the behavior of the people in the building 2 using a planning function. Specifically, plans of people entering or leaving the building 2, going from the building 2 to another location, or returning to the building 2 are collected by the detector 10. Based on the data collected by the detector 10, the control unit 8 predicts the time of day when the number of people in the building 2 is high. At the time when the number of people in the building 2 is assumed to be high, the control unit 8 predicts that the concentration of CO2 in the exhaust gas emitted by the building 2 will be higher than at the time when the number of people in the building 2 is small.

[0041] The control unit 8 is configured to perform a calculation based on the incoming data and the data and formulas stored therein, and transmit the calculation result in the form of a command signal. For example, to control a flow rate of the exhaust gas transmitted from the building 2 to the CO2 capture device 4, the control unit 8 transmits command signals to the flow rate regulator 7 to control an opening degree of the flow rate regulator 7, or to open or close the flow rate regulator 7. On the other hand, assuming that the fan is used as the flow rate regulator 7, the control unit 8 controls the gust of wind generated by the flow rate regulator 7.

[0042] In particular, the control unit 8 comprises a timer 21, an information collector 22, a flow rate calculator 23, and a flow rate controller 24.

[0043] The timer 21 collects information about a required time, such as a time of day, a control time, an elapsed time, etc., to start controlling a flow rate of CO2. For example, the timer 21 collects data about the time of day when the number of people in the building 2 is large or small. Based on the information collected by the timer 21, the control unit 8 determines the time of day when a concentration of CO2 in the exhaust gas discharged from the building 2 is high or low. Furthermore, the control unit 8 determines a timing and intervals to execute the control of a flow rate of CO2 based on the information collected by the timer 21.

[0044] The information collector 22 collects various types of data to control a flow rate of CO2. Specifically, the information collector 22 obtains data on a concentration of CO2 in the exhaust gas emitted from the building 2 based on the data collected by the CO2 sensor 9. Furthermore, the information collector 22 obtains data on the number of people in the building 2 and the behavior of the people in the building 2 based on the data collected by the detector 10. On the other hand, the information collector 22 may also obtain data on the number of people in the building 2 based on video data collected by the camera or data collected by a sensor (not shown).

[0045] The flow rate calculator 23 calculates a flow rate of the exhaust gas transmitted from each of the buildings 2 to the CO2 capture device 4 based on the data collected by the timer 21 and the information collector 22. For example, in a case where a concentration of CO2 in the exhaust gas transmitted from the building 2 is low, a flow rate of the exhaust gas transmitted to the CO2 capture device 4 is reduced compared to a case where a concentration of CO2 in the exhaust gas discharged from the building 2 is high. Meanwhile, in a case where the number of people in the building 2 is high, the control unit 8 estimates that the concentration of CO2 in the exhaust gas discharged from the building 2 is higher than in a case where the number of people in the building 2 is small. In this case, the flow rate of the exhaust gas transmitted to the CO2 capture device 4 is increased.

[0046] The flow rate controller 24 controls the flow rate regulator 7 based on the flow rate of the exhaust gas transmitted from the building 2 to the CO2 capture device 4, which is calculated by the flow rate calculator 23. For example, when the valve is assumed to be the flow rate regulator 7, the flow rate controller 24 opens or closes the flow rate regulator 7, or controls an opening degree of the flow rate regulator 7 based on the flow rate of the exhaust gas calculated by the flow rate calculator 23. On the other hand, when the fan is assumed to be used as the flow rate regulator 7, the flow rate controller 24 controls the gust of wind generated by the flow rate regulator 7.

[0047] Although only one control unit 8 is used in the Fig. 1, a plurality of control units may be arranged in the CO2 capture system 1 to individually control each building and device. Optionally, each of the flow rate controllers 7 may be provided with its associated computer (not shown). In this case, the control unit 8 comprises these computers and a main server (not shown), which are mounted at a predetermined location.

[0048] The CO2 capture device 4 can also be arranged in each of the buildings 2. Referring to Fig. 2, an example of the arrangement of a CO2 capture device 31 in each of the buildings 2 in the Smart City is shown to individually capture CO2 from the exhaust gas emitted by each of the buildings 2. In the Fig. 2, the same reference numerals designate the same components as in Fig. 1 shown elements.

[0049] Each of the CO2 capture devices 31 has the same function as the CO2 capture device 4 of the previous example. According to the Fig. In the example shown in Figure 2, the flow rate regulators 7 are arranged on flow paths 32 connecting the buildings 2 to the CO2 capture devices 31. Specifically, the CO2-containing exhaust gas discharged from the building 2 flows through the flow path 32 toward the CO2 capture device 31 via the flow rate regulator 7. The CO2 in the exhaust gas transmitted to the CO2 capture device 31 is separated and captured by the CO2 capture device 31, and then transmitted from the CO2 capture device 31 to the CO2 storage tank 5 via a flow path 33 not only in the liquid phase but also in the gas phase, depending on the capture method.

[0050] As described, the CO2 capture system according to the exemplary embodiment of the present invention is configured to efficiently capture CO2 from the exhaust gas emitted by the buildings 2. To this end, the control unit 8 in Fig. 3 to Fig. 8 routines or programs shown.

[0051] Referring to Fig. 3 shows an example of the routine or program for controlling a flow rate of the exhaust gas supplied from the building 2 to the CO2 capture device 4 or 31 according to the time, which takes into account a concentration of CO2 in the exhaust gas. In step S11, it is determined whether it is time to control a flow rate of the exhaust gas supplied from the buildings 2 to the CO2 capture device 4 or 31. Specifically, the time to control the flow rate is set to a period or a time at which a concentration of CO2 in the exhaust gas discharged from the building 2 is changed or is expected to be changed. For example, in step S1, if it is assumed that the building 2 is a shop or restaurant, it is determined whether it is the opening time of the shop or restaurant.In this case, after the opening time of the store or restaurant, the control unit 8 estimates that the number of people in the store or restaurant increases, and a concentration of CO2 in the exhaust gas emitted from the store or restaurant increases. Meanwhile, in step S11, assuming that the building 2 is a house, it is determined whether it is (average) time for the residents to go to work or school, or whether it is time for the residents to return to the building 2. In this case, the control unit 8 estimates that after the time when the residents go to work or school, the number of people in the building 2 decreases, and a concentration of CO2 in the exhaust gas emitted from the building 2 decreases.

[0052] If the actual time is before the time at which the flow rate is controlled, so the answer to step S11 is NO, the routine returns. Conversely, if it is time to control the flow rate of the exhaust gas, so the answer to step S11 is YES, the routine proceeds to step S12 to control the flow rate controller 7 to regulate the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 to a desired rate.

[0053] Specifically, in step S12, an opening degree of the valve or a gust of wind generated by the fan is adjusted to regulate the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 to a desired rate. For example, when it is time to open the store, the flow rate controller 7 is controlled in such a manner as to increase a flow rate of the exhaust gas flowing toward the CO2 capture device 4 or 31. In contrast, when it is time for the residents of the building 2 to go to work, the flow rate controller 7 is controlled in such a manner as to decrease a flow rate of the exhaust gas flowing toward the CO2 capture device 4 or 31.

[0054] In addition, when CO2 emission from the occupants of the building 2 is substantially zero, for example, when no one is in the house during the day or when no one is in the office overnight, the supply or transmission of the exhaust gas to the CO2 capture device 4 or 31 can be stopped by controlling the flow rate controller 7.

[0055] After controlling the flow rate controller 7 to adjust the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 to the desired rate, the routine or program returns.

[0056] Therefore, the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 is controlled to the desired rate when it is assumed that the concentration of CO2 in the exhaust gas changes. For example, when the number of residents in the building 2 is high, the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 is increased compared to the case where the number of residents in the building 2 is small. On the other hand, when there is no one in the building 2, the supply of the exhaust gas to the CO2 capture device 4 or 31 is stopped. That is, the flow rate of the exhaust gas supplied to the CO2 capture device 4 or 31 is reduced to zero. Therefore, according to the exemplary embodiment of the present invention, a large amount of the exhaust gas in which a concentration of CO2 is high can be supplied to the CO2 capture device 4 or 31.In other words, a supply amount of the exhaust gas in which a concentration of CO2 is low to the CO2 capture device 4 or 31 is reduced. For this reason, CO2 can be efficiently captured by the CO2 capture device 4 or 31 from the exhaust gas discharged from the building 2.

[0057] Referring to Fig. 4 shows an example of the routine or program to collect behavioral data of the people entering and leaving the building 2, which is used to estimate a concentration of CO2 in the exhaust gas emitted by the building 2. For example, the Fig. 4 is executed by the detector 10, such as a mobile terminal, and a microcomputer (not shown), which are in or in connection with a surveillance camera. In step S21, it is determined whether the behavior of the residents of the building 2 changes based on the behavior data collected by the detector 10. For example, the resident's behavior data may be collected based on location information of the mobile terminals carried by the resident, and the detector 10 determines that the resident's behavior changes when the resident enters the building 2. In contrast, when the resident goes out of the building 2, the detector 10 also determines that the resident's behavior changes.In addition, the number of residents of the building 2 is detected as the behavior data by the surveillance camera installed in the building 2, and the detector 10 determines that the resident's behavior changes when the number of residents of the building 2 changes.

[0058] If the number of visitors or residents of building 2 has not changed, so the answer in step S21 is NO, the routine or program returns. Conversely, if the number of residents of building 2 has changed, so the answer in step S21 is YES, the routine or program proceeds to step S22 to transmit the behavior data acquired in step S21 to the control unit 8.

[0059] In step S22, in particular, the behavioral data, such as the number of residents carrying the mobile devices, are transmitted from the mobile devices to the information collector 22 of the control unit 8. Instead, the behavioral data, such as the number of residents, are transmitted from the surveillance camera to the information collector 22 of the control unit 8.

[0060] After transmitting the behavior data from the detector 10 to the control unit 8 in step S22, the routine or program returns.

[0061] Referring to Fig. 5 shows an example of the routine or program to directly detect a concentration of CO2 in the exhaust gas emitted by building 2. The routine, which is described in Fig. 5 is carried out by means of a microcomputer (not shown) arranged in or in connection with the CO2 sensor 9. In step S31, it is determined whether a concentration of CO2 in the exhaust gas emitted from the building 2 (or in the building 2), which is detected by the CO2 sensor 9, has changed, or whether the CO2 sensor 9 newly detects a concentration of CO2 in the exhaust gas emitted from the building 2 (or in the building 2). Specifically, in step S31, it is determined whether a concentration of CO2 in the exhaust gas currently detected by the CO2 sensor 9 has changed by more than a predetermined value from a concentration of CO2 in the exhaust gas previously detected by the CO2 sensor 9. On the other hand, if a predetermined value of a concentration of CO2 in the exhaust gas is not available, it is determined in step S31 whether the CO2 sensor 9 detects a concentration of CO2 in the exhaust gas for the first time.

[0062] If the CO2 concentration currently measured by the CO2 sensor 9 has not changed by more than the predetermined value, or if the CO2 sensor 9 has not yet detected the CO2 concentration, so that the answer to step S31 is NO, the routine or program returns. Conversely, if the CO2 concentration detected by the CO2 sensor 9 has changed by more than the predetermined value, or if the CO2 sensor 9 has detected the CO2 concentration for the first time, so that the answer to step S31 is YES, the routine or program proceeds to step S32 to transmit data on the CO2 concentration to the control unit 8.

[0063] In step S32, in particular, the data relating to the concentration of CO2 in the exhaust gas emitted by the building 2 are transmitted from the CO2 sensor 9 to the information collector 22 of the control unit 8.

[0064] After transmitting the data concerning the concentration of CO2 from the CO2 sensor 9 to the control unit 8 in step S32, the routine or program returns.

[0065] Referring to Fig. 6, an example of the routine is shown to determine a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31 based on the results obtained by executing the steps described in the Fig. 4 and Fig. 5 shown programs to regulate the data collected. The routine, which is Fig. 6 is executed by the control unit 8. In step S41, it is determined whether the information collector 22 of the control unit 8 receives the behavior data from the detector 10 or the data concerning the concentration of CO2 from the CO2 sensor 9.

[0066] If the information collector 22 has not yet received the data from the detector 10 or the CO2 sensor 9, so that the answer in step S41 is NO, the routine returns. Conversely, if the information collector 22 receives the data from the detector 10 or the CO2 sensor 9, so that the answer in step S41 is YES, the routine proceeds to step S42 to control a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31 based on the data transmitted from the detector 10 or the CO2 sensor 9.

[0067] Specifically, in step S42, the flow rate controller 7 is controlled based on the behavioral data transmitted from the detector 10 to the information collector 22, or the data concerning the CO2 concentration transmitted from the CO2 sensor 9 to the information collector 22. For example, the flow rate controller 7 is controlled in such a manner as to increase the flow rate of the exhaust gas flowing toward the CO2 capture device 4 or 31 with an increase in the CO2 concentration in the exhaust gas, which is estimated based on the behavioral data of the occupants of the building 2 detected by the detector 10, or directly detected by the CO2 sensor 9.

[0068] After controlling the flow rate of the exhaust gas flowing from the building 2 toward the CO2 trapping device 4 or 31 in step S42, the routine or program returns.

[0069] Referring to Fig. 7 shows an example of the routine for storing the data transmitted from the detector 10 or the CO2 sensor 9 to the control unit 8. The Fig. The program shown in Figure 7 is executed by the control unit 8 and a database connected to the control unit 8. The database can be installed in the control unit 8 or in an external server. Assuming that the database is installed in the external server, the database is enabled to exchange data with the control unit 8. In step S51, it is determined whether the information collector 22 of the control unit 8 receives the behavior data from the detector 10 or the data concerning the CO2 concentration from the CO2 sensor 9.

[0070] If the information collector 22 has not yet received the data from the detector 10 or the CO2 sensor 9, so that the answer in step S51 is NO, the routine returns. Conversely, if the information collector 22 has received the data from the detector 10 or the CO2 sensor 9, so that the answer in step S41 is YES, the routine proceeds to step S52 to store the data transmitted from the detector 10 or the CO2 sensor 9.

[0071] In step S52, in particular, the behavioral data transmitted from the detector 10 to the information collector 22, or the data concerning the concentration of CO2 transmitted from the CO2 sensor 9 to the information collector 22 are stored in the database.

[0072] After saving the above data in the database, the routine or program returns.

[0073] Referring to Fig. Figure 8 shows an example of the routine or program for controlling a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31 based on the data stored in the database. Fig. The routine shown in Figure 8 is also executed by the control unit 8 and the database connected to the control unit 8. In step S61, it is determined whether a predetermined period of time has elapsed from the last time the flow rate controller 7 was controlled to regulate the flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31.

[0074] If the predetermined time period has not yet elapsed from the last time the flow rate controller 7 was controlled, so that the answer to step S61 is NO, the routine returns. Conversely, if the predetermined time period has elapsed from the last time the flow rate controller 7 was controlled, so that the answer to step S61 is YES, the routine proceeds to step S62 to control a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31 based on the data stored in the database.

[0075] Specifically, in step S62, a flow rate of the exhaust gas flowing from the building 2 toward the CO2 capture device 4 or 31 is calculated based on the data stored in the database, and the flow rate controller 7 is controlled based on the calculated flow rate. For example, the flow rate controller 7 is controlled in such a manner that the flow rate of the exhaust gas flowing toward the CO2 capture device 4 or 31 increases with an increase in the concentration of CO2 in the exhaust gas, which is estimated based on the data stored in the database.Specifically, during the period in which the estimated concentration of CO2 in the exhaust gas is high, the flow rate controller 7 is controlled in such a manner that the flow rate of the exhaust gas flowing toward the CO2 capture device 4 or 31 is increased compared to the period in which the estimated concentration of CO2 in the exhaust gas is low. Meanwhile, in a case where the estimated concentration of CO2 in the exhaust gas is less than a predetermined value (e.g., in the case where there is none in the building 2), the flow rate controller 7 is controlled in such a manner that the supply of the exhaust gas to the CO2 capture device 4 or 31 is stopped.

[0076] After regulating the flow rate of the exhaust gas flowing from the building 2 toward the CO2 trapping device 4 or 31 in step S62, the routine returns.

[0077] Therefore, in the CO2 capture system 1, the flow rate regulators 7 are arranged between the buildings 2 and the CO2 capture device(s) 4 or 31 in the smart city. According to the exemplary embodiment of the present invention, the flow rates of the exhaust gases flowing from the buildings 2 toward the CO2 capture device(s) 4 or 31 can be individually controlled according to the concentrations of CO2 in the exhaust gases. For this reason, the CO2 capture device(s) 4 or 31 can only be operated when the concentrations of CO2 in the exhaust gases are high, and CO2 can be efficiently captured by the CO2 capture device(s) 4 or 31 from the exhaust gases emitted by the buildings 2.

Claims

[1] CO2 capture system (1), comprising: a CO2 capture device (4, 31) which separates and captures CO2 from the air; a plurality of buildings (2); and a flow path (3) which supplies an exhaust gas emitted from the building (2) to the CO2 capture device (4, 31) in order to capture the CO2 from the exhaust gas by the CO2 capture device (4, 31), characterized by : a flow rate controller (7) which controls a flow rate of the exhaust gas flowing from the building (2) toward the CO2 capture device (4, 31) through the flow path (3); and a control unit (8) which controls the flow rate controller (7) to regulate the flow rate of the exhaust gas. [2] CO2 capture system (1) according to claim 1, wherein the control unit (8) is configured to: to collect information concerning a concentration of CO2 in the exhaust gas emitted by the building (2); and to control the flow rate controller (7) based on the collected information. [3] CO2 capture system (1) according to claim 2, further comprising: a detector (10) which collects behavioral data from residents of the building (2), including the number of people entering and leaving the building (2) and the behavior of the people in the building (2), wherein the control unit (8) is further configured to: to receive the behavioral data of the residents of the building (2); and to control the flow rate of the exhaust gas based on the behavior data. [4] CO2 capture system (1) according to claim 3, wherein the control unit (8) is further configured to increase the flow rate of the exhaust gas with an increase in the number of occupants of the building (2). [5] The CO2 capture system (1) according to claim 3, wherein the control unit (8) is further configured to increase the flow rate of the exhaust gas during a period in which the number of residents of the building (2) is high compared to a period in which the number of residents of the building (2) is small. [6] CO2 capture system (1) according to one of claims 3 to 5, wherein the control unit (8) is further configured to stop supplying the exhaust gas from the building (2) to the CO2 capture device (4, 31) when none is in the building (2). [7] CO2 capture system (1) according to claim 3, wherein the control unit (8) is further configured to: to estimate the concentration of CO2 in the exhaust gas emitted by the building (2) based on the behavioral data of the occupants of the building (2); and to increase the flow rate of the exhaust gas with an increase in the concentration of CO2 in the exhaust gas. [8] CO2 capture system (1) according to claim 1 or 2, further comprising: a CO2 sensor (9) which detects a concentration of CO2 in the exhaust gas emitted by the building (2), wherein the control unit (8) is further configured to increase the flow rate of the exhaust gas with an increase in the concentration of CO2 in the exhaust gas detected by the CO2 sensor (9). [9] CO2 capture system (1) according to one of claims 1 to 8, wherein the flow rate regulator (7) comprises a valve arranged between the building (2) and the CO2 capture device (4, 31), and the control unit (8) is further configured to regulate the flow rate of the exhaust gas by actuating the valve. [10] CO2 capture system (1) according to one of claims 1 to 8, wherein the flow rate regulator (7) comprises a fan arranged between the building (2) and the CO2 capture device (4, 31), and the control unit (8) is further configured to regulate the flow rate of the exhaust gas by controlling a gust of wind generated by the fan.

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