Carbon dioxide recovery system

Abstract

This carbon dioxide recovery system comprises: a separation unit that separates carbon dioxide from an adsorbent having a function of adsorbing carbon dioxide and regenerates the adsorbent; a heat supply unit that is provided with heat sources including a first heat source, which is a heat source derived from renewable energy, and that supplies heat necessary for regenerating the adsorbent to the separation unit; and a switching control unit that switches the heat sources for supplying the heat to the separation unit. The switching control unit switches the heat sources for supplying the heat to the separation unit on the basis of a priority defining the order in which the heat sources are to be used and a control criterion for determining the availability of the heat sources.

Description

Carbon dioxide capture system

[0001] This disclosure relates to a carbon dioxide capture system. This application claims priority to Japanese Patent Application No. 2024-151192, filed on September 3, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, attention has been focused on Direct Air Capture (DAC) systems that capture carbon dioxide by adsorbing carbon dioxide at low concentrations (e.g., about 410 ppm) in the atmosphere onto an adsorbent. In such carbon dioxide capture systems, after carbon dioxide is adsorbed onto the adsorbent, the adsorbent may be heated to desorb the carbon dioxide from the adsorbent. In Patent Document 1, energy obtained from a solar power generation device is used to heat the adsorbent to desorb the carbon dioxide.

[0003] Japanese Patent Application Publication No. 2020-131166

[0004] The energy obtained from a solar power generation system is affected by the amount of solar radiation. When there is no solar radiation or when there is insufficient radiation, it is necessary to switch the heat source for heating the adsorbent from the solar power generation system to another heat source. In such cases, there was a need for a system that could select a heat source that consumes less energy when desorbing carbon dioxide from the adsorbent, taking into account weather conditions and the amount of heat emitted by surrounding equipment.

[0005] In view of the above circumstances, the present disclosure aims to provide a carbon dioxide capture system that can reduce the amount of energy consumed when desorbing carbon dioxide from an adsorbent and reduce the cost of capturing carbon dioxide.

[0006] The carbon dioxide capture system disclosed herein comprises a separation unit that separates carbon dioxide from an adsorbent having the function of adsorbing carbon dioxide and regenerates the adsorbent, a heat source including a first heat source that is a heat source derived from renewable energy and supplies the heat necessary for regenerating the adsorbent to the separation unit, and a switching control unit that switches the heat source that supplies the heat to the separation unit, and the switching control unit switches the heat source that supplies the heat to the separation unit based on a priority that determines the order in which the heat sources are used and a control criterion for determining whether the heat source can be used.

[0007] According to the present disclosure, it is possible to provide a carbon dioxide capture system that can reduce the amount of energy consumed when desorbing carbon dioxide from an adsorbent and reduce the cost of capturing carbon dioxide.

[0008] FIG. 1 is a schematic diagram showing a general configuration of a carbon dioxide capture system according to embodiment 1. FIG. 2 is a schematic diagram showing an example of the general configuration of a separation unit and a heat supply unit of a carbon dioxide capture system according to embodiment 1. FIG. 3 is a schematic diagram showing another example of the general configuration of a separation unit and a heat supply unit of a carbon dioxide capture system according to embodiment 1. FIG. 4 is a flowchart showing the operation of pattern 4 of a carbon dioxide capture system according to embodiment 1. FIG. 5 is a flowchart showing the operation of pattern 5 of a carbon dioxide capture system according to embodiment 1. FIG. 6 is a flowchart showing the operation of pattern 6 of a carbon dioxide capture system according to embodiment 1. FIG. 7 is a flowchart showing the operation of pattern 7 of a carbon dioxide capture system according to embodiment 1. FIG. 8 is a schematic diagram showing a general configuration of a carbon dioxide capture system according to embodiment 2.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure.

[0010] First Embodiment First, in the first embodiment, the basic configuration of a carbon dioxide capture system 1 will be described. Figures 1A to 1C are schematic diagrams of a carbon dioxide capture system 1 according to the first embodiment. As shown in Figure 1A, the carbon dioxide capture system 1 has an adsorption unit 10A that adsorbs carbon dioxide onto an adsorbent 11, a separation unit 10B that desorbs carbon dioxide from the adsorbent 11, a concentration unit 10C that concentrates the desorbed carbon dioxide, and a storage unit 10D that stores the carbon dioxide.

[0011] In the adsorption section 10A, the adsorbent 11 comes into contact with the carbon dioxide-containing gas to adsorb carbon dioxide in the carbon dioxide-containing gas. The adsorption of carbon dioxide by the adsorbent 11 is achieved, for example, by contacting the adsorbent 11 with a carbon dioxide-containing gas containing carbon dioxide at a low concentration (e.g., about 410 ppm) present in the atmosphere in the adsorption section 10A. Adsorption of low-concentration carbon dioxide in the atmosphere by the adsorbent 11 in this manner is particularly referred to as DAC (Direct Air Capture). The carbon dioxide-containing gas may be, for example, a gas discharged from a fluid equipment such as an outdoor unit of an air conditioner, an indoor unit of an air conditioner, or a ventilation fan. The carbon dioxide-containing gas may also be a gas discharged from a produced gas discharge device of an oil refinery, an exhaust gas system of a power plant, or the like. The carbon dioxide-containing gas is not limited to a gas discharged from the above-mentioned equipment, but may also be a gas discharged from other equipment.

[0012] The adsorbent 11 that has adsorbed carbon dioxide is transferred from the adsorption section 10A to the separation section 10B. The adsorbent 11 may be transferred from the adsorption section 10A by an operator or by a transfer means such as a robot arm or a belt conveyor operated by a program. In the separation section 10B, the adsorbed carbon dioxide can be desorbed from the adsorbent 11 by changing the temperature and / or pressure. The desorption of carbon dioxide from the adsorbent 11 is preferably carried out in the environment inside the separation vessel 12 of the separation section 10B until the amount of carbon dioxide adsorbed by the adsorbent 11 reaches equilibrium. After the carbon dioxide desorption process from the adsorbent 11 is completed, the adsorbent 11 is removed from the separation section 10B, and a new adsorbent 11 that has adsorbed carbon dioxide is placed in the separation section 10B. The adsorbent 11 from which carbon dioxide has been desorbed in the separation section 10B may be transferred to the adsorption section 10A and reused for carbon dioxide adsorption. The gas containing carbon dioxide desorbed from the adsorbent 11 is sent to the concentration section 10C.

[0013] The concentrating unit 10C increases the concentration of carbon dioxide in the carbon dioxide-containing gas recovered from the separation unit 10B, concentrating the carbon dioxide. For example, a permeable membrane for separating carbon dioxide from other components may be used, or an adsorbent 11 may be used as in the separation unit 10B. Carbon dioxide may also be concentrated by other methods. The storage unit 10D has, for example, a cylinder capable of storing carbon dioxide. The storage unit 10D may store carbon dioxide in a liquefied or solid form. Note that the concentrating unit 10C and the storage unit 10D are not essential components of the carbon dioxide capture system 1 and may be omitted.

[0014] In the carbon dioxide capture system 1, the adsorbent 11 is heated in the separation unit 10B to desorb carbon dioxide from the adsorbent 11 that has adsorbed carbon dioxide in the adsorption unit 10A. Conventionally, a heater or boiler has been used as a heat source for heating the adsorbent 11, but this has sometimes increased the energy consumption of the carbon dioxide capture system and raised the cost of carbon dioxide capture. Therefore, in the present embodiment, in order to reduce the energy consumption of the carbon dioxide capture system 1, a heat source 21 derived from renewable energy is used as the heat source for supplying heat to the separation unit 10B.

[0015] As shown in FIGS. 1B and 1C , the carbon dioxide capture system 1 includes a separation unit 10B that separates carbon dioxide from an adsorbent 11 having a carbon dioxide adsorption function and regenerates the adsorbent 11, and a heat supply unit 20 that includes a heat source 20h including a renewable energy-derived heat source 21 and supplies the heat necessary to regenerate the adsorbent 11 to the separation unit 10B. The renewable energy-derived heat source 21 may not generate a constant amount of heat because it uses energy found in nature, for example. Therefore, in this embodiment, a switching control unit 40 is provided that switches the heat source 20h that supplies heat to the separation unit 10B based on a priority order that determines the order in which the heat sources 20h are used and a control standard for determining whether the heat source 20h is usable. Details of the desorption of carbon dioxide in the separation unit 10B and the heat supply to the separation unit 10B are described below.

[0016] <Separation Unit 10B> The separation unit 10B includes a separation container 12. An adsorbent 11 is disposed in the separation container 12. The adsorbent 11 contains a material capable of adsorbing carbon dioxide. Examples of materials for the adsorbent 11 include amine, zeolite, silica gel, diatomaceous earth, alumina, and activated carbon. Multiple materials may be selected from the above, or other materials may be used. The adsorbent 11 may be granular (e.g., bead-shaped (spherical) or pellet-shaped (cylindrical)). Alternatively, the adsorbent 11 may be powder-shaped. The amount of adsorbent 11 disposed in the separation container 12 can be appropriately changed based on the size of the separation container 12 and the amount of heat that can be supplied. In the examples of FIGS. 1B and 1C, the adsorbent 11 is disposed on the bottom surface of the separation container 12.

[0017] The adsorbent 11 may be supported on the surface of a substrate. The substrate may be, for example, a plate having a honeycomb structure in which a plurality of approximately hexagonal holes smaller than the particle diameter are formed. The adsorbent 11 may also be housed in a breathable case. For example, the adsorbent 11 may be housed in a case in which a plurality of holes smaller than the particle diameter of the adsorbent 11 are formed. The case may be formed entirely or partially of a net-like mesh with wire woven into it. The materials of the substrate and case can be changed as appropriate, and may be metal or resin. Structures other than those described above may also be employed for the substrate and case.

[0018] The separation container 12 is a container that can accommodate the adsorbent 11. For example, the separation container 12 is a box-shaped container composed of six sides. Note that the separation container 12 is not limited to a box shape and may be, for example, cylindrical. The separation container 12 has an opening (not shown) for putting the adsorbent 11 in and taking it out of the separation container 12, and a door portion (not shown) that airtightly seals the opening. The opening is an opening through which the adsorbent 11, or a substrate and case that include the adsorbent 11, can pass.

[0019] In the separation container 12, the carbon dioxide adsorbed in the adsorbent 11 is desorbed by heating and / or reducing the pressure. In the example shown in FIGS. 1B and 1C , a thermometer 12t is provided for measuring the temperature of the separation container 12. In addition to the thermometer 12t, sensors such as a humidity sensor and a pressure sensor may be provided for measuring humidity and pressure. Furthermore, a carbon dioxide concentration sensor for measuring the concentration of desorbed carbon dioxide may be provided. The measurement results of the thermometer 12t and the various sensors are transmitted to the switching control unit 40. In this embodiment, heat is supplied from the heat supply unit 20 to the separation container 12 to desorb carbon dioxide from the adsorbent 11.

[0020] <Heat Supply Unit 20> The heat supply unit 20 includes a heat source 20h. The heat source 20h includes one or more renewable energy-derived heat sources 21 (first heat sources 21). In FIG. 1B, the heat source 20h includes multiple first heat sources 21. As shown in FIG. 1C, the heat source 20h may include, in addition to the renewable energy-derived heat source 21, a heat conversion device 22 (second heat source 22) such as a heater that can be operated using electricity or the like. Here, the "renewable energy-derived heat source 21 (first heat source 21)" in this specification refers to a heat source that generates heat from energy that is always present in nature, such as sunlight, or a heat source that does not generate additional carbon dioxide even when heat is utilized, and the "heat conversion device 22 (second heat source 22)" does not include the renewable energy-derived heat source 21 and generates heat by converting electricity into heat. Hereinafter, in this specification, the "renewable energy-derived heat source 21" will be referred to as the "first heat source 21," and the "heat conversion device 22" will be referred to as the "second heat source 22." Furthermore, when either the first heat source 21 or the second heat source 22 is acceptable, it will be simply referred to as the "heat source 20h."

[0021] First Heat Source 21 The first heat source 21 generates heat from energy always present in nature, such as sunlight, and is, for example, a solar thermal collector. There are many types of solar thermal collectors, and any known type may be used. For example, the separation container 12 may be heated by directly irradiating sunlight onto it, by reflecting light onto it using a mirror, or by covering it with a solar thermal collector. The solar thermal collector may also be configured to convert sunlight's light energy into thermal energy and supply the heat to the separation section 10B via a heat medium. Examples of heat sources that do not generate additional carbon dioxide when used include equipment with an exhaust heat source and an exhaust heat recovery device. Examples of equipment with an exhaust heat source include air conditioners, fuel cells, and control panels. When the additional heat generated by these devices is used to heat the adsorbent 11, it can be said that no additional carbon dioxide is generated. In the case of an outdoor unit of an air conditioner, the exhaust heat source may also be equipped with air blowing power. In this way, when the exhaust heat source also has a blowing power, the blowing power may be used as a power for transporting heat to the separation unit 10B, and heat may be supplied to the separation unit 10B. The exhaust heat recovery device is a device that recovers exhaust heat from equipment having these exhaust heat sources. The first heat source 21 of the heat supply unit 20 may be one or more of these heat sources.

[0022] Second heat source 22 The second heat source 22 is a device that generates heat by converting electric power into heat, and can be used as a backup heat source when the first heat source 21 is unavailable. There are many heating methods for the second heat source 22, and any known method may be used. The second heat source 22 may be equipped with a private power generation facility and use electric power from the private power generation facility as its operating power. The private power generation facility may be a power generation system that utilizes solar panels and excess heat from various devices, or may be another power generation system. Note that even if the electric power used is generated from renewable energy, a device that generates heat by converting electric power into heat does not fall under the category of "first heat source 21" in this specification, but rather falls under the category of "second heat source 22."

[0023] Heat source 20h Each heat source 20h has a temperature sensor for measuring the temperature of the heat source 20h. The heat source temperature measurement results obtained by the temperature sensor provided in the heat source 20h are transmitted to the switching control unit 40. In addition, the first heat source 21 transmits to the switching control unit 40 measurement information such as the amount of generated heat and the operating state of the exhaust heat source. The second heat source 22 transmits to the switching control unit 40 information such as the power supply status to the second heat source 22, the amount of power generated in the private power generation facility, and the accumulated amount of generated power. Information including information on the temperature of the heat source 20h and the operating state of the heat source 20h is hereinafter referred to as "heat source operation information." The heat source operation information can also be said to be information on the amount of heat generated by the heat source 20h. The heat source operation information is transmitted to the switching control unit 40. Note that the heat source operation information is not limited to the above example and may include other information about the heat source 20h. Furthermore, it is not necessary to measure all of the above heat source operation information; it is preferable that at least one piece of information be transmitted to the switching control unit 40. Furthermore, as will be described in detail later, the heat source operation information may not be measured, and only the environmental information may be transmitted from the environmental condition measurement unit 50 to the switching control unit 40. In other words, it is sufficient that at least one of the heat source operation information and the environmental information is transmitted to the switching control unit 40.

[0024] Preferably, each heat source 20h is equipped with a heat storage device. When there is excess heat when the separation unit 10B is not operating, the excess heat can be stored in the heat storage device. This makes it possible to prevent a decrease in heat source efficiency. Information such as the amount of heat stored in each heat source 20h is transmitted from the heat storage device to the switching control unit 40.

[0025] 1B and 1C, a supply line 30 is provided connecting the heat supply unit 20 to the separation vessel 12 to transport heat, and a heat medium heated by a heat source 20h is transported to the separation unit 10B via the supply line 30. The supply line 30 is, for example, a pipe, and can transport heat using the heat medium even when the heat source 20h and the separation unit 10B are separated from each other. When the heat medium is air, a blower may be installed between the heat source 20h and the separation unit 10B to supply heated air to the separation unit 10B.

[0026] The supply line 30 is provided with an on-off valve 30v that controls whether or not heat is transported to the separation container 12. The heat supply line connecting from the first heat source 21 to the separation unit 10B is referred to as the first heat supply line 31, and the on-off valve that controls whether or not heat is transported in the first heat supply line 31 is referred to as the first on-off valve 31v. The heat supply line connecting from the second heat source 22 to the separation unit 10B is referred to as the second heat supply line 32, and the on-off valve that controls whether or not heat is transported in the second heat supply line 32 is referred to as the second on-off valve 32v. The opening and closing of the first on-off valve 31v and the second on-off valve 32v is controlled by the switching control unit 40.

[0027] The first heat supply line 31 and the second heat supply line 32 are provided with a first line thermometer 31t and a second line thermometer 32t, respectively, for measuring the temperature of the heat medium being transported. The measurement results of the first line thermometer 31t and the second line thermometer 32t are transmitted to the switching control unit 40. The first line thermometer 31t and the second line thermometer 32t may be omitted. For example, if the temperature of the heat medium flowing through the supply line 30 can be predicted from measurement information from a sensor for measuring the operating status of the heat source 20h, the first line thermometer 31t and the second line thermometer 32t may not be provided.

[0028] The method of transporting heat to the separation unit 10B is not limited to the example of transporting heated air as a heat medium through the supply line 30. For example, a heat medium other than heated air may be used, such as a gas containing water vapor. The heat medium is not limited to gas, and may be heated water. Furthermore, the separation container 12 and the heat source 20h may be arranged in direct contact with each other, and heat may be transported from the heat source 20h to the separation unit 10B by thermal conduction between the separation container 12 and the housing of the heat source 20h. Alternatively, heat may be supplied to the separation unit 10B by supplying a heat medium to a heat exchanger arranged outside the separation container 12 and heating the separation container 12 from the outside. Furthermore, when multiple heat sources 20h are thermally connected to the separation unit 10B, the methods of transporting heat from the multiple heat sources 20h to the separation unit 10B may be different for each heat source. For example, heat may be transported from one heat source 20h by thermal conduction due to direct contact between the separation container 12 and the housing of the heat source 20h, and heat may be transported from another heat source 20h to the separation section 10B by transporting heated air through the supply line 30.

[0029] <Environmental Condition Measurement Unit 50> As described above, the first heat source 21 may generate an inconstant amount of heat because it uses, for example, energy present in nature. Furthermore, the amount of heat actually generated by the heat source 20h may vary depending on the temperature around the heat source 20h. Therefore, the carbon dioxide recovery system 1 of this embodiment includes an environmental condition measurement unit 50 that measures the conditions of the environment in which the heat source 20h is installed. The environmental condition measurement unit 50 includes sensors including, for example, a photometer and a thermometer for measuring the outside air temperature. The type of sensor provided in the environmental condition measurement unit 50 can be appropriately selected depending on the type of heat source 20h used. Hereinafter, the measurement results of the sensors provided in the environmental condition measurement unit 50 will be referred to as "environmental information." The environmental information can also be considered information for predicting or correcting heat source operation information. The environmental information is transmitted to the switching control unit 40.

[0030] The information transmitted to the switching control unit 40, including the heat source operation information and the environmental information, will be referred to hereinafter as "measurement information." The measurement information further includes measurement information from the thermometers 12t, 31t, and 32t.

[0031] <Switching control unit 40> The switching control unit 40 receives the various types of measurement information described above and determines whether the measurement information of the heat source 20h satisfies the control criteria. Alternatively, the switching control unit 40 may calculate the amount of heat generated by the heat source 20h from the measurement information and determine whether the calculated amount of heat generated satisfies the control criteria.

[0032] As an example, a case will be described in which the control criterion is the appropriate temperature range for desorbing carbon dioxide from the adsorbent 11. When the temperature of the heat source 20h is within the appropriate temperature range, i.e., when the measurement information of the heat source 20h is within the control criterion, the switching control unit 40 determines that the heat source 20h is usable. The appropriate temperature range is, for example, from 50°C to 120°C. Generally, the higher the temperature, the smaller the equilibrium adsorption amount of carbon dioxide in the adsorbent 11, and the reaction proceeds in the direction of releasing carbon dioxide from the adsorbent 11. The range of 50°C to 120°C is the temperature range in which the carbon dioxide release reaction from the adsorbent 11 that has adsorbed carbon dioxide at room temperature proceeds favorably. Using a temperature-based control criterion makes it possible to accurately determine whether carbon dioxide can be separated from the adsorbent 11. The appropriate temperature range may be changed as appropriate depending on the type of adsorbent 11, the target carbon dioxide desorption amount, etc.

[0033] The control standard is not limited to the appropriate temperature range of the heat source 20h. The control standard may be determined based on the amount of heat required to bring the temperature inside the separation container 12 into the appropriate temperature range. Furthermore, as will be described in patterns 8 and 9 below, the control standard may be the appropriate range of heat source operation information acquired from the control panel of the heat source 20h or environmental information such as the amount of solar radiation at the location where the heat source 20h is installed.

[0034] If the switching control unit 40 determines that the heat source 20h satisfies the control criteria, that heat source 20h is used to heat the separation unit 10B. If there are multiple heat sources 20h that are determined to be usable, the heat source 20h with the highest ranking is used according to priority. Below, using examples of patterns 1 to 9, the determination by the switching control unit 40 as to whether or not the heat source 20h can be used based on the control criteria and the priority order for using the heat source 20h will be described in detail.

[0035] Pattern 1: The heat supply unit 20 has only one or more first heat sources 21 as the heat source 20h (see FIG. 1B ). As shown in FIG. 2 , the switching control unit 40 acquires the control criterion for the first heat source 21 (S11). Next, it determines whether the measurement information of the first heat source 21 satisfies the control criterion (S12). If the first heat source 21 satisfies the control criterion, heat from the first heat source 21 with the highest priority is supplied to the separation container 12 (S13). Here, if only one first heat source 21 satisfies the control criterion, that one heat source has the highest priority, and heat from that one heat source is supplied to the separation container 12. If multiple first heat sources 21 satisfy the control criterion, heat is supplied to the separation container 12 from the heat source with the highest priority among the multiple heat sources. If the first heat source 21 does not satisfy the control criterion, heat is not supplied to the separation container 12 (S14).

[0036] Here, for example, the "priority order" is set based on the energy consumption of the heat source 20h. Specifically, the "priority order" is given to the heat source 20h that can reduce its energy consumption more. When the first heat source 21 and the second heat source 22 are compared, the first heat source 21 consumes less energy. Therefore, the priority order of the first heat source 21 is higher than that of the second heat source 22. Regarding the priority order of multiple first heat sources 21, the heat source that can reduce its energy consumption more is given higher priority. When the energy consumption of multiple first heat sources 21 is equivalent, the order may be determined appropriately taking into consideration the priority of use of the heat generated from each heat source, etc.

[0037] Pattern 2: When the heat supply unit 20 has a first heat source 21 and a second heat source 22 (see FIG. 1C ). As shown in FIG. 3 , the switching control unit 40 acquires the control criteria for the heat source 20h (S21). Next, it determines whether the measurement information for each heat source 20h satisfies the control criteria (S22). If none of the heat sources satisfies the control criteria, heat is not supplied to the separation container 12 (S23). If one or more heat sources 20h satisfy the control criteria, it determines whether the first heat source 21 satisfies the control criteria (S24). If one or more first heat sources 21 satisfy the control criteria, the first heat source 21 with the highest priority is selected and supplies heat to the separation container 12 (S25). If the first heat source 21 does not satisfy the control criteria and the second heat source 22 is the only heat source 20h that satisfies the control criteria, heat from the second heat source 22 is supplied to the separation container 12 (S26).

[0038] Pattern 3: The heat supply unit 20 has a first heat source 21 and a second heat source 22, each including an exhaust heat recovery device and a solar thermal collector. In Pattern 3, the first heat source 21 includes an exhaust heat recovery device and a solar thermal collector. Because the exhaust heat from the power-consuming equipment is actively utilized, the exhaust heat recovery device is prioritized higher than the solar thermal collector. In Pattern 3, the flow up to S22 and S23 are similar to those in Pattern 2, and therefore will not be described here. If one or more heat sources 20h satisfy the control criteria, as shown in FIG. 4, it is determined whether the first heat source 21 satisfies the control criteria (S34). If the first heat source 21 satisfies the control criteria, it is determined whether the exhaust heat recovery device satisfies the control criteria (S35). If the exhaust heat recovery device satisfies the control criteria, heat from the exhaust heat recovery device is supplied to the separation vessel 12 (S36). If the exhaust heat recovery device does not satisfy the control standard, i.e., if the solar heat collecting device satisfies the control standard, heat from the solar heat collecting device is supplied to the separation container 12 (S37). If the first heat source 21 does not satisfy the control standard and the second heat source 22 is the only heat source that satisfies the control standard, heat from the second heat source 22 is supplied to the separation container 12 (S38).

[0039] In the example of pattern 3, the exhaust heat recovery device is given a higher priority than the solar thermal collector. However, the solar thermal collector may be given a higher priority. For example, the priority may be changed in consideration of the measurement results of the photometer of the environmental condition measurement unit 50, so that heat leaking from the solar thermal collector is used preferentially. In other words, the priority may be changed as appropriate based on the heat source measurement information and the environmental information.

[0040] Pattern 4: When heat is supplied to the separation unit 10B from two or more heat sources 20h simultaneously. In patterns 1 to 3, even if multiple heat sources 20h meet the control criteria, only the heat from the heat source 20h with the highest priority is used, and the heat from the other heat sources 20h is not used, which may result in heat loss. Therefore, in pattern 4, when there are two or more heat sources 20h that meet the control criteria, two heat sources 20h are used, thereby reducing the heat loss from the heat sources 20h that meet the control criteria.

[0041] As shown in FIG. 5A , the switching control unit 40 acquires the control criteria for the heat source 20h (S41). Next, it determines whether two or more heat sources 20h satisfy the control criteria (S42). If two or more heat sources 20h satisfy the control criteria, the heat sources 20h with the highest and second highest priorities are selected from the two or more heat sources 20h and simultaneously supply heat to the separation container 12 (S43). If two or more heat sources 20h do not satisfy the control criteria, heat is not supplied to the separation container 12 (S46). In pattern 4, the heat supply unit 20 may have only the first heat source 21, or the heat supply unit 20 may have both the first heat source 21 and the second heat source 22. If the heat supply unit 20 has both the first heat source 21 and the second heat source 22 and S42 is "Yes," the second highest priority heat source may be the second heat source 22.

[0042] Furthermore, in pattern 4, heat may be supplied to the separation container 12 when there are at least one heat source 20h that satisfy the control criteria, even if two or more heat sources 20h do not satisfy the control criteria. For example, as shown in FIG. 5B , the switching control unit 40 acquires the control criteria for the heat source 20h (S41′). Here, the control criteria include a second control criterion that allows two heat sources 20h to maintain the separation container 12 within the appropriate temperature range, and a first control criterion that allows one heat source 20h to maintain the separation container 12 within the appropriate temperature range. The first control criterion is the same as the control criterion in patterns 1 to 3. Next, it is determined whether there are two or more heat sources 20h that satisfy the second control criterion (S42′). If there are two or more heat sources 20h that satisfy the second control criterion, the heat sources 20h with the highest and second highest priorities are selected from the two or more heat sources 20h and simultaneously supply heat to the separation container 12 (S43′). If there are fewer than two heat sources 20h that satisfy the second control criterion, the control unit 40 determines whether there is one heat source 20h that satisfies the first control criterion (S44'). If there is one heat source 20h that satisfies the first control criterion, heat is supplied from that one heat source 20h to the separation container 12 (S45'). If there are no heat sources 20h that satisfy the first control criterion, heat is not supplied to the separation container 12 (S46'). Note that in Pattern 4, an example was described in which two heat sources, ranked first and second in priority, are used among the multiple heat sources 20h that satisfy the control criterion. However, the number of heat sources 20h used simultaneously is not limited to two. The number of heat sources 20h used simultaneously can be changed as appropriate, and two or more heat sources 20h may be used. For example, if there are N or more heat sources 20h that satisfy the control criterion, the switching control unit 40 may supply heat to the separation unit 10B from the N heat sources 20h with the highest priority among the heat sources 20h that satisfy the control criterion. Furthermore, the control criteria may include N control criteria from the first control criteria to the Nth control criteria, and the switching control unit 40 may determine whether or not N or fewer heat sources 20 h are usable, where N is a natural number equal to or less than the number of heat sources 20 h.

[0043] In pattern 4, if the answer is "Yes" in S42 or S42', heat is supplied from two heat sources 20h to the separation container 12. In this case, the methods of transporting heat from the two heat sources 20h to the separation unit 10B may be different. For example, heat may be transported from one heat source 20h by thermal conduction due to direct contact between the separation container 12 and the housing of one heat source 20h, and heat may be transported from the other heat source 20h to the separation unit 10B by transporting heated air through a supply line.

[0044] Pattern 5: The switching control unit 40 determines again after a certain time has elapsed whether each heat source 20h satisfies the control criteria. For example, in patterns 1 to 4, the heat source 20h determined to satisfy the control criteria continues to be used. However, over time, the amount of heat generated by each heat source 20h may change, causing a heat source 20h with a higher priority to become available, or the heat source 20h that was being used to no longer satisfy the control criteria. Therefore, in pattern 5, the switching control unit 40 determines again after a certain time has elapsed whether the heat source 20h satisfies the control criteria.

[0045] As shown in FIG. 6 , the switching control unit 40 acquires the control criteria for the heat source 20h (S51). Next, it determines whether the measurement information for the heat source 20h satisfies the control criteria (S52). If the heat source 20h satisfies the control criteria, heat from the heat source 20h with the highest priority is supplied to the separation container 12 (S53). If the heat source 20h does not satisfy the control criteria, heat is not supplied to the separation container 12 (S54). After a certain period of time has elapsed since S53 or S54, the process returns to S51, and the switching control unit 40 again determines whether the heat source 20h satisfies the control criteria. Then, heat from the highest-ranking heat source 20h among the heat sources 20h that satisfy the control criteria is supplied to the separation unit 10B (S52). Steps S51 through S54 may be repeated until the amount of carbon dioxide desorption from the adsorbent 11 reaches the target value. In this way, in pattern 5, the switching control unit 40 can switch to the heat source 20h that can most effectively reduce energy consumption at that timing every time a certain period of time has elapsed. If the heat source 20h that satisfies the control criteria remains the same even after a certain time has passed, the heat source 20h will continue to supply heat without stopping or switching the heat source 20h.

[0046] Pattern 6: After a certain period of time has elapsed since the second heat source 22 was used, the switching control unit 40 again checks whether each heat source 20h satisfies the control criteria. For example, in patterns 1 to 4, if it is determined that the second heat source 22 satisfies the control criteria, the second heat source 22 continues to be used. However, it is conceivable that the state of the other heat sources 20h changes and the first heat source 21 begins to satisfy the control criteria. Because the first heat source 21 can reduce energy consumption more than the second heat source 22, in this case, it is preferable to stop using the second heat source 22 and switch to using the first heat source 21. Therefore, in pattern 6, after a certain period of time has elapsed since the second heat source 22 was used, it is again determined whether each heat source 20h satisfies the control criteria.

[0047] The steps for determining whether to use the second heat source 22 for heat supply are the same as those in patterns 1 to 4, and therefore will not be described or illustrated in FIG. 7 . As shown in FIG. 7 , after a certain period of time has elapsed since the second heat source 22 started supplying heat (S6a), the switching control unit 40 acquires the control standard for the heat source 20h (S61). Next, it determines whether each heat source 20h satisfies the control standard (S62). If any heat source 20h satisfies the control standard, it determines whether that heat source 20h is the first heat source 21 (S63). If that heat source 20h is the first heat source 21, the operation of the second heat source 22 is stopped (S64), and heat from the first heat source 21, which has the highest priority, is supplied to the separation container 12 (S65). If that heat source 20h is not the first heat source 21, the second heat source 22 continues to be used (S66). In S62, if none of the heat sources 20h meets the control criteria, heat is not supplied to the separation container 12 (S67).

[0048] After a certain time has elapsed since S65, S66, or S67, the process returns to S61, and the switching control unit 40 again determines whether the heat source 20h satisfies the control criteria (S62). S61 through S67 may be repeated to desorb carbon dioxide from the adsorbent 11. Thus, in pattern 6, the switching control unit 40 can switch to the heat source 20h that can most effectively reduce energy consumption at that timing every time a certain time has elapsed. Note that in pattern 6, the second heat source 22 is stopped in S64, but there is a possibility that the second heat source 22 will be used again in a step that is repeated after a certain time has elapsed. Therefore, the second heat source 22 may be placed in a standby state rather than being stopped in S64. In the standby state, the second heat source 22 reduces power consumption while also reducing power consumption when the second heat source 22 is used again.

[0049] Pattern 7: When the measurement information of the first heat source 21 exceeds the control standard. Cases where the measurement information of the first heat source 21 does not satisfy the control standard include a case where the amount of heat generated by the first heat source 21 is insufficient and the measurement information of the first heat source 21 is less than the control standard, and a case where the amount of heat generated by the first heat source 21 is excessive and the measurement information of the first heat source 21 exceeds the control standard. Therefore, in patterns 1 to 6, even when the measurement information of the first heat source 21 exceeds the control standard, it is determined that the control standard is not satisfied. Even in this case, it is possible to use only the necessary amount of heat generated by the first heat source 21, or to lower the temperature of the first heat source 21 before use.

[0050] For ease of explanation, pattern 7 will be described assuming that the heat supply unit 20 has only the first heat source 21 as the heat source 20h, but the heat supply unit 20 may also have a second heat source 22. As shown in Fig. 8 , the switching control unit 40 acquires a control criterion for the first heat source 21 (S71). Next, it is determined whether the measurement information of the first heat source 21 satisfies the control criterion (S72). If the first heat source 21 satisfies the control criterion, heat from the first heat source 21 with the highest priority is supplied to the separation container 12 (S73).

[0051] If the first heat source 21 does not satisfy the control standard, the control unit 40 determines whether the measurement information of the first heat source 21 exceeds the control standard (S74). If the measurement information of the first heat source 21 exceeds the control standard, the control unit 40 controls the first heat source 21 so that the measurement information of the first heat source 21 falls within the control standard. For example, the operating status of the first heat source 21 may be adjusted, or excess heat may be released to a location other than the separation unit 10B. Then, heat from the adjusted first heat source 21 is supplied to the separation container 12 (S75). If S74 is No, heat is not supplied from the first heat source 21 to the separation container 12 (S76). Thus, in Pattern 7, even if the first heat source 21 exceeds the control standard, energy can be used effectively, thereby reducing energy consumption.

[0052] Pattern 8: Determining whether heat source operation information satisfies the control criteria. In pattern 8, when the first heat source 21 includes an exhaust heat recovery device, the measurement results of existing sensors and the like provided in the exhaust heat source are used as the heat source operation information. For example, when an outdoor unit of an air conditioner is used as the exhaust heat source, the heat source operation information includes the power consumption of the outdoor unit, the fan rotation speed, and the vibration volume of the compressor. This heat source operation information can be obtained from the control panel of the outdoor unit of the air conditioner. When existing sensors are used as the heat source operation information, there is no need to install a new sensor in the heat source 20h for use in the carbon dioxide capture system 1. Furthermore, the installation of the first and second line thermometers 31t and 32t may be omitted. This also makes it possible to reduce the initial cost of installing sensors and the power consumption of the sensors.

[0053] In pattern 8, an example was described in which only heat source operation information is compared with the control standard, but measurement information including both heat source operation information and environmental information may also be compared with the control standard, as in pattern 8' below.

[0054] Pattern 8': When determining whether the heat source operation information and environmental information satisfy the control criteria. When an air conditioner's outdoor unit is used as the exhaust heat source, environmental information including the date and time the exhaust heat is used, trend data on the annual and hourly average temperatures at the installation location of the air conditioner's outdoor unit, and the outdoor temperature measured by an outdoor air thermometer may be used to determine whether the control criteria are satisfied. The trend data on the annual and hourly average temperatures may be statistical data input into the environmental condition measurement unit 50. The heat generated from the exhaust heat source of the air conditioner's outdoor unit may vary depending on the outdoor temperature even under the same operating conditions. Therefore, the heat source operation information is corrected based on environmental information including the outdoor temperature. Specifically, for example, the heat generation amount of the heat source calculated from the heat source operation information is corrected to approximate the actual heat generation amount based on the outdoor temperature in the environmental information. This allows for more accurate comparison with the control criteria. The heat generation amount correction method may be appropriately modified in consideration of the actual heat generation amount at the installation location and operating conditions of the heat source 20h and the theoretical formula for predicting the amount.

[0055] In patterns 8 and 8', a method for determining whether heat source 20h satisfies the control criteria is described using only heat source operation information or measurement information of both heat source operation information and environmental information. However, as described in pattern 9 below, the amount of heat generated by heat source 20h may also be calculated from environmental information alone.

[0056] Pattern 9: Determining whether environmental information satisfies the control criteria. In Pattern 9, measurement data from various sensors provided in the environmental condition measurement unit 50 is used as environmental information for the first heat source 21 (e.g., a solar heat collector). Here, environmental information includes measurement data from an outside thermometer, pyranometer, or illuminometer, as well as trend data on the annual and hourly average temperature and solar radiation at the installation location of the heat source 20h. Note that the trend data on weather conditions may also be statistical data input into the environmental condition measurement unit 50. In Pattern 9, the temperature of the first heat source 21 can be predicted without directly measuring the temperature of the first heat source 21, and it can be determined whether the first heat source 21 satisfies the control criteria. Below, Patterns 9A to 9D, which are specific examples of Pattern 9, are described.

[0057] Pattern 9A: When determining whether the amount of solar radiation satisfies the control standard for the solar heat collector. In pattern 9A, the measurement data of the amount of solar radiation from a pyranometer or illuminometer provided in the environmental condition measurement unit 50 is used as environmental information. The amount of solar radiation is the amount of solar radiant energy [W / m ] received per unit area per unit time, measured by a pyranometer or illuminometer. 2 In pattern 9A, the control criterion is the appropriate range of solar radiation. The appropriate range of solar radiation may be a range in which the temperature of the solar thermal collector is predicted to be between 50°C and 120°C. The appropriate range of solar radiation may also be determined appropriately based on data on trends in the annual average and hourly average air temperature at the installation location of the solar thermal collector, and on the actual value of the heat generation amount at that location and time period and a theoretical formula for prediction. When the amount of solar radiation satisfies the control criterion, it is determined that heat from the solar thermal collector can be supplied to the separation container 12.

[0058] If the environmental condition measurement unit 50 does not include a pyranometer and can use measurement data from a solar radiation sensor installed in a location that can receive solar energy equivalent to that of the solar thermal collector, the measurement results of the sensor may be used as environmental information. This makes it possible to omit the installation of a pyranometer in the environmental condition measurement unit 50. The solar radiation sensor may be installed, for example, in the building where the solar thermal collector is installed or in a nearby location. This also makes it possible to reduce the initial cost for installing the sensor and the power consumption of the sensors.

[0059] Pattern 9B: A case in which whether the control criteria for a solar thermal collector are satisfied is determined based on the amount of power generated by the solar panels. Pattern 9B assumes that the solar panels are installed in close proximity to the solar thermal collector, allowing the solar thermal collector and the solar panels to receive equivalent solar energy. For example, the solar panels may be installed inside the building where the solar thermal collector is installed or near the solar thermal collector. Because the solar panels are installed in a location where they can receive equivalent solar energy as the solar thermal collector, the amount of power generated by the solar panels can be used as environmental information. In Pattern 9B, the control criteria is set to the appropriate range of power generation by the solar panels. The appropriate range of power generation by the solar panels may be a range in which the temperature of the solar thermal collector is predicted to be between 50°C and 120°C. Using the amount of power generation by the solar panels as environmental information eliminates the need to install new sensors required to acquire various information about the solar thermal collector. This reduces the initial cost of installing sensors and the power consumption of the sensors.

[0060] Pattern 9C: A case in which it is determined whether the control criteria for the solar thermal collector are met based on the temperature of the solar panel. In Pattern 9C, similar to Pattern 9B, the temperature of the solar panel installed in a location that can receive the same amount of solar energy as the solar thermal collector is used as environmental information. In Pattern 9C, the control criteria is the appropriate range of the solar panel temperature. The appropriate range of the solar panel temperature may be a range in which the temperature of the solar thermal collector is predicted to be between 50°C and 120°C. When the temperature of the solar panel is used as environmental information, it is possible to avoid installing new sensors that are required to acquire various information about the solar thermal collector. This makes it possible to reduce the initial cost of installing the sensors and the power consumption of the sensors.

[0061] Pattern 9D: A case in which it is determined whether environmental information, including weather conditions at the location where the first heat source 21 is installed, satisfies the control criteria. In Pattern 9D, measurement data from a weather condition acquisition system placed under weather conditions similar to those of the first heat source 21 is used as the environmental information. For example, the weather condition acquisition system may be installed inside the building where the first heat source 21 is installed or near the first heat source 21. The weather condition acquisition system uses sensors to measure the weather status, sunshine hours, outdoor temperature, and the like. In Pattern 9D, the control criteria are weather conditions. The weather conditions may be conditions in which the temperature of the first heat source 21 is predicted to be between 50°C and 120°C. The environmental information possessed by the weather condition acquisition system may include trend data on the annual average and hourly average temperature and solar radiation at the location where the first heat source 21 is installed, which are input into the system in advance. This allows not only to determine whether the control criteria are satisfied at the time of measurement based on the sensor measurement results, but also to predict whether the control criteria will be satisfied at a future time based on the trend data on temperature and solar radiation. This prediction makes it possible to control in advance whether or not the first heat source 21 and peripheral devices of the heat source need to be activated. When using a system that acquires weather conditions in this way, it becomes possible to use a heat source that is suitable for reducing energy consumption. Furthermore, based on the predicted weather conditions, it becomes possible to further reduce energy consumption. It is also possible to reduce the initial cost of installing sensors on the heat source and the power consumption of the sensors.

[0062] As described above, the carbon dioxide capture system 1 is equipped with a separation unit 10B that separates carbon dioxide from an adsorbent 11 having the function of adsorbing carbon dioxide and regenerates the adsorbent 11, a heat source 20h including a first heat source 21 that is a heat source derived from renewable energy and supplies the heat necessary for regenerating the adsorbent 11 to the separation unit 10B, and a switching control unit 40 that switches the heat source 20h that supplies heat to the separation unit 10B, and the switching control unit 40 switches the heat source 20h that supplies the heat to the separation unit 10B based on a priority that determines the order in which the heat sources 20h are used and a control criterion for determining whether the heat source 20h can be used.

[0063] In this way, the optimal heat source 20h can be selected and used based on the priority order and control criteria, thereby reducing the amount of energy consumed when desorbing carbon dioxide from the adsorbent 11 and reducing the cost of carbon dioxide capture.

[0064] The heat supply unit 20 further includes a second heat source 22 that generates heat by converting electric power into heat as the heat source 20h. This allows the second heat source 22 to be used as a backup heat source 20h when the first heat source 21 cannot be used.

[0065] Furthermore, the switching control unit 40 supplies heat to the separation unit 10B from one heat source with the highest priority among the heat sources 20h that satisfy the control criteria. This makes it possible to use the heat source 20h that can most effectively reduce the amount of energy consumed when desorbing carbon dioxide from the adsorbent 11.

[0066] Furthermore, when there are N or more heat sources 20h that satisfy the control criteria (where N is a natural number), the switching control unit 40 supplies heat to the separation unit 10B from the top N heat sources 20h that satisfy the control criteria, in order of priority. This makes it possible to use multiple heat sources 20h that satisfy the control criteria. Therefore, heat loss from the heat sources 20h that satisfy the control criteria can be reduced.

[0067] The heat source 20h includes a first heat source 21 and a second heat source 22 that generates heat by converting electric power into heat, and the first heat source 21 has a higher priority than the second heat source 22. Comparing the first heat source 21 and the second heat source 22, the first heat source 21 consumes less energy. Therefore, by giving the first heat source 21 a higher priority, it is possible to reduce the amount of energy consumed when desorbing carbon dioxide from the adsorbent 11.

[0068] The first heat source 21 includes an exhaust heat recovery device and a solar heat collector, and the exhaust heat recovery device has a higher priority than the solar heat collector. In this case, the exhaust heat from the power-consuming equipment can be actively utilized.

[0069] The control standard is determined based on the amount of heat required to set the temperature inside separation vessel 12 of separation unit 10B within an appropriate temperature range for desorbing carbon dioxide from adsorbent 11. By using the temperature-based control standard, it is possible to accurately determine whether carbon dioxide can be separated from adsorbent 11. For example, the appropriate temperature range is from 50°C to 120°C. Within this range, the carbon dioxide release reaction from adsorbent 11 that has adsorbed carbon dioxide at room temperature proceeds favorably.

[0070] The switching control unit 40 also determines whether at least one of the heat source operation information, including information on the temperature and operating status of the heat source 20h, and the environmental information, which measures the conditions of the environment in which the heat source 20h is installed, satisfies the control criteria. This allows optimal measurement information to be used when determining whether the heat source 20h can be used. Furthermore, since the number of sensors required to obtain the measurement information can be reduced, the initial cost for installing the sensors and the power consumption of the sensors can be reduced.

[0071] The switching control unit 40 also determines whether the temperature of the heat source 20h satisfies a control criterion. By using a control criterion based on temperature, it is possible to accurately determine whether carbon dioxide can be separated from the adsorbent 11. Furthermore, since sensors other than the thermometer of the heat source 20h can be omitted, it is also possible to reduce the initial cost for installing sensors and the power consumption of the sensors.

[0072] Furthermore, the first heat source 21 includes an exhaust heat recovery device, and the switching control unit 40 determines whether heat source operation information of the exhaust heat source of the exhaust heat recovery device satisfies the control standard. The first heat source 21 includes a solar heat collecting device, and the switching control unit 40 determines whether the amount of solar radiation on the solar heat collecting device satisfies the control standard. The first heat source 21 includes a solar heat collecting device, and the switching control unit 40 determines whether the amount of power generation of a solar panel capable of receiving solar energy equivalent to that of the solar heat collecting device satisfies the control standard. The first heat source 21 includes a solar heat collecting device, and the switching control unit 40 determines whether the temperature of the solar panel capable of receiving solar energy equivalent to that of the solar heat collecting device satisfies the control standard. The switching control unit 40 determines whether the weather conditions at the location where the heat source 20h is installed in the first heat source 21 satisfy the control standard.

[0073] In this way, whether or not the heat source 20h can be used can be determined based on whether the heat source operation information or environmental information satisfies the control criteria. Furthermore, if environmental information can be obtained from equipment other than the carbon dioxide capture system 1, it is possible to reduce the initial cost for installing sensors and the power consumption of the sensors.

[0074] Furthermore, when a certain time has elapsed since the heat source 20h started to supply heat to the separation unit 10B, the switching control unit 40 again determines whether each heat source 20h satisfies the control standard. As a result, every time a certain time has elapsed, the switching control unit 40 can switch to the heat source 20h that can most effectively reduce energy consumption at that timing.

[0075] Furthermore, when a certain time has elapsed since the second heat source 22 started supplying heat to the separation unit 10B, the switching control unit 40 again determines whether each heat source 20h satisfies the control standard. As a result, every time a certain time has elapsed, the switching control unit 40 can switch to the heat source 20h that can most effectively reduce energy consumption at that timing.

[0076] Furthermore, when it is determined that the amount of heat generated by the first heat source 21 exceeds the control standard, the switching control unit 40 controls the amount of heat generated by the first heat source 21 so that the amount of heat generated by the first heat source 21 satisfies the control standard. This allows for effective energy use even when the amount of heat generated by the first heat source 21 exceeds the control standard.

[0077] The system further includes an adsorption section 10A that adsorbs carbon dioxide onto the adsorbent 11, a concentration section 10C that increases the carbon dioxide concentration of the carbon dioxide-containing gas recovered from the separation section 10B, and a storage section 10D that stores the concentrated carbon dioxide. This allows for the recovery of carbon dioxide using the adsorbent 11 to be performed in an optimal manner.

[0078] Second Embodiment Next, a carbon dioxide capture system 1 according to a second embodiment will be described with reference to Fig. 9. The carbon dioxide capture system 1 according to this embodiment has the same basic configuration as the first embodiment, and therefore differences will be mainly described.

[0079] In the first embodiment, the adsorption unit 10A and the separation unit 10B are provided separately, but in the present embodiment, as shown in Fig. 9, the adsorption unit 10A in the first embodiment is integrated with the separation unit 10B, and adsorption and desorption of carbon dioxide to the adsorbent 11 are carried out in the same separation vessel 12. In other words, the separation unit 10B in this embodiment can also be said to be an adsorption / separation unit.

[0080] Gas containing carbon dioxide flows into the separation section 10B in which the adsorbent 11 is disposed, and the carbon dioxide comes into contact with the adsorbent 11, thereby adsorbing the carbon dioxide to the adsorbent 11 (adsorption process). The adsorption process is performed, for example, at room temperature. After the adsorption process, the flow of gas containing carbon dioxide into the adsorption / separation section 10B is stopped, and heat from the heat source 20h that satisfies the control criteria as described in the first embodiment is supplied to the separation vessel 12, thereby raising the temperature in the separation vessel 12 to, for example, an appropriate temperature range (separation process). After the amount of carbon dioxide adsorbed by the adsorbent 11 reaches equilibrium within the appropriate temperature range, the supply of heat to the adsorption / separation section 10B is terminated. The gas containing carbon dioxide desorbed from the adsorbent 11 is transferred to the concentration section 10C and the storage section 10D.

[0081] A cooler (not shown) may be connected to the adsorption / separation section 10B. After the separation step, before performing the adsorption step again in the same separation vessel 12, the separation vessel 12 may be cooled by the cooler to return the adsorption / separation section 10B and the adsorbent 11 to room temperature (cooling step).

[0082] The switching control unit 40 may have a function of switching between the adsorption process and the separation process in the separation unit 10B. For example, the switching control unit 40 may control the process to switch from the separation process to the adsorption process when a certain time has elapsed since the heat supply unit 20 started to supply heat to the separation unit 10B. Furthermore, if a cooler is connected to the separation container 12, the switching control unit 40 may control the cooler to perform the cooling process after the separation process.

[0083] As described above, in the carbon dioxide capture system 1, carbon dioxide is adsorbed onto the adsorbent 11 in the separation vessel 12 of the separation unit 10B, and then the carbon dioxide is separated from the adsorbent 11 to regenerate the adsorbent 11. This makes it possible to preferably capture carbon dioxide using the adsorbent 11, as in the first embodiment.

[0084] In addition, the above-described embodiments and modifications may be combined as appropriate.

[0085] 1B illustrates an example in which two first heat sources 21 are provided in the heat supply unit 20, but the heat supply unit 20 may be provided with only one first heat source 21. In this case, the switching control unit 40 switches whether or not to use the one first heat source 21 to supply heat to the separation unit 10B.

[0086] 2 , if there is no heat source 20h that satisfies the control standard, heat is not supplied to the separation unit 10B, which may result in a decrease in the efficiency of separation of carbon dioxide from the adsorbent 11. In this case, carbon dioxide may be desorbed from the adsorbent 11 by a method other than heating the adsorbent 11. For example, a vacuum pump may be connected to the separation vessel 12, and carbon dioxide may be desorbed from the adsorbent 11 by reducing the pressure inside the separation vessel 12.

[0087] The above-described switching control unit 40 has an internal computer system. A program for realizing the functions of each component included in the above-described carbon dioxide capture system 1 may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into and executed by the computer system to perform the processing in the above-described switching control unit 40. Furthermore, hardware other than the switching control unit 40 may perform the above-described processing.

[0088] Here, "loading a program recorded on a recording medium into a computer system and executing it" includes installing the program into a computer system. The "computer system" here includes the OS and hardware such as peripheral devices.

[0089] Furthermore, a "computer system" may include multiple computer devices connected via a network including the Internet or communication lines such as a WAN, LAN, or dedicated line. Furthermore, a "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Thus, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0090] The recording medium also includes internal or external recording media accessible from a distribution server for distributing the program. The program may be divided into multiple parts, downloaded at different times, and then combined by each component of the carbon dioxide capture system 1. Each divided program may be distributed by a different distribution server. Furthermore, the term "computer-readable recording medium" also includes a medium that stores a program for a certain period of time, such as volatile memory (RAM) within a computer system that serves as a server or client when a program is transmitted over a network. The program may also be a medium for implementing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the above-described functions in combination with a program already stored in the computer system.

[0091] DESCRIPTION OF SYMBOLS 1... Carbon dioxide recovery system, 10A... Adsorption section, 10B... Separation section, 10C... Concentration section, 10D... Storage section, 11... Adsorbent, 12... Separation vessel, 20... Heat supply section, 20h... Heat source, 21... First heat source, 22... Second heat source, 40... Switching control section, 50... Environmental condition measurement section

Claims

1. A carbon dioxide recovery system comprising: a separation unit that separates carbon dioxide from an adsorbent having the function of adsorbing carbon dioxide and regenerates the adsorbent; a heat supply unit that has a heat source including a first heat source that is a heat source derived from renewable energy and supplies the heat necessary to regenerate the adsorbent to the separation unit; and a switching control unit that switches the heat source that supplies the heat to the separation unit, wherein the switching control unit switches the heat source that supplies the heat to the separation unit based on a priority that determines the order in which the heat sources are used and a control criterion for determining whether the heat source can be used.

2. The carbon dioxide recovery system according to claim 1, wherein the heat supply unit further has, as the heat source, a second heat source that generates heat by converting electric power into heat.

3. A carbon dioxide capture system according to claim 1 or 2, wherein the switching control unit supplies heat to the separation unit from one heat source with the highest priority among the heat sources that satisfy the control criteria.

4. A carbon dioxide recovery system as described in claim 1 or 2, wherein, when there are N or more heat sources that satisfy the control criteria, where N is a natural number, the switching control unit supplies heat to the separation unit from the N highest heat sources that satisfy the control criteria in order of priority.

5. A carbon dioxide recovery system as described in any one of claims 2 to 4, wherein the heat sources include the first heat source and a second heat source that generates heat by converting electricity into heat, and the first heat source has a higher priority than the second heat source.

6. A carbon dioxide recovery system as described in any one of claims 1 to 5, wherein the first heat source includes an exhaust heat recovery device and a solar thermal heat collector, and the exhaust heat recovery device is ranked higher than the solar thermal heat collector in the priority order.

7. A carbon dioxide recovery system as described in any one of claims 1 to 6, wherein the control standard is determined based on the amount of heat required to bring the temperature inside the separation container of the separation section into an appropriate temperature range for desorbing carbon dioxide from the adsorbent.

8. A carbon dioxide recovery system as described in any one of claims 1 to 7, wherein the switching control unit determines whether at least one of heat source operation information including information on the temperature and operating status of the heat source and environmental information measuring the conditions of the environment in which the heat source is installed satisfies the control standard.

9. The carbon dioxide capture system according to any one of claims 1 to 8, wherein the switching control unit determines whether the temperature of the heat source satisfies the control standard.

10. A carbon dioxide recovery system as described in any one of claims 1 to 8, wherein the first heat source includes an exhaust heat recovery device, and the switching control unit determines whether the heat source operation information of the exhaust heat source of the exhaust heat recovery device satisfies the control standard.

11. A carbon dioxide recovery system as described in any one of claims 1 to 8, wherein the first heat source includes a solar heat collecting device, and the switching control unit determines whether the amount of solar radiation on the solar heat collecting device satisfies the control standard.

12. A carbon dioxide recovery system as described in any one of claims 1 to 8, wherein the first heat source includes a solar thermal collector, and the switching control unit determines whether the amount of power generated by a solar panel capable of receiving solar energy equivalent to that of the solar thermal collector satisfies the control standard.

13. A carbon dioxide recovery system as described in any one of claims 1 to 8, wherein the first heat source includes a solar heat collector, and the switching control unit determines whether the temperature of a solar panel capable of receiving solar energy equivalent to that of the solar heat collector satisfies the control standard.

14. A carbon dioxide recovery system as described in any one of claims 1 to 8, wherein the switching control unit determines whether or not the weather conditions at the location where the first heat source is installed satisfy the control criteria.

15. A carbon dioxide capture system as described in any one of claims 1 to 14, wherein, when a certain time has elapsed since the heat source started to supply heat to the separation unit, the switching control unit again determines whether each of the heat sources satisfies the control criteria.

16. A carbon dioxide recovery system as described in any one of claims 1 to 15, wherein the heat supply unit further has a second heat source as the heat source that generates heat by converting electricity into heat, and when a certain time has elapsed since the second heat source started to supply the heat to the separation unit, the switching control unit again determines whether each of the heat sources satisfies the control standard.

17. A carbon dioxide recovery system as described in any one of claims 1 to 16, wherein, when it is determined that the amount of heat generated by the first heat source exceeds the control standard, the switching control unit controls the amount of heat generated by the first heat source so that it satisfies the control standard.

18. A carbon dioxide capture system as described in any one of claims 1 to 17, further comprising: an adsorption section that adsorbs carbon dioxide onto the adsorbent; a concentration section that increases the carbon dioxide concentration of the carbon dioxide-containing gas recovered from the separation section; and a storage section that stores the concentrated carbon dioxide.

19. A carbon dioxide capture system according to any one of claims 1 to 17, wherein after carbon dioxide is adsorbed onto the adsorbent in the separation vessel of the separation section, the carbon dioxide is separated from the adsorbent to regenerate the adsorbent.

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