Carbon dioxide application system

Abstract

To efficiently apply CO2 to cultivated plants. [Solution] The carbon dioxide application device 100 includes first and second adsorption sections 1a and 1b, temperature control sections 3a and 3b for adjusting the temperature of the adsorption sections, a control unit 10 that alternately switches between an operating mode between a first mode in which the temperature control section is controlled so that the first adsorption section is at the adsorption temperature and the second adsorption section is at the desorption temperature, and a second mode in which the temperature control section is controlled so that the first adsorption section is at the desorption temperature and the second adsorption section is at the adsorption temperature, a blower 2 for blowing air to the adsorption sections via an inlet flow path P1, an application section for applying the desorbed gas containing CO2 desorbed from the adsorption sections to cultivated plants, and an extraction section for combining extracted gas, obtained by extracting a portion of the air flowing through the inlet flow path, with the desorbed gas. The extraction section has an extraction adjustment section 7 for adjusting the degree of extraction. The control unit further controls the extraction adjustment section so that the CO2 concentration of the desorbed gas after the extraction gas has been combined becomes a predetermined concentration.

Description

[Technical Field]

[0001] This invention relates to a carbon dioxide application device for applying carbon dioxide (CO2) to cultivated plants. [Background technology]

[0002] One type of device known is one that recovers CO2 from the air and applies it to cultivated plants. For example, in the device described in Patent Document 1, exhaust gas from a combustion device is introduced into an absorption section having an absorbent material that absorbs CO2, and the CO2 contained in the exhaust gas is recovered. The CO2 that has been released from the absorption section is stored in a storage section, and the CO2 stored in the storage section is used to push out the exhaust gas remaining in the absorption section, thereby supplying the purge gas discharged from the absorption section to an agricultural greenhouse. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-95195 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, there is a limit to the amount of CO2 that cultivated plants can consume through photosynthesis. However, supplying CO2 using a device like the one described in Patent Document 1 may result in an excessive supply of CO2, making it difficult to efficiently apply CO2 to cultivated plants. [Means for solving the problem]

[0005] A carbon dioxide application device according to one aspect of the present invention comprises: a first adsorption section and a second adsorption section, each having an adsorbent configured to adsorb carbon dioxide at a predetermined adsorption temperature and desorb carbon dioxide at a desorption temperature higher than the adsorption temperature; a temperature adjustment section for adjusting the respective temperatures of the first and second adsorption sections; a control section that alternately switches between an operating mode between a first mode, which controls the temperature adjustment section so that the adsorbent in the first adsorption section is at the adsorption temperature and the adsorbent in the second adsorption section is at the desorption temperature, and a second mode, which controls the temperature adjustment section so that the adsorbent in the first adsorption section is at the desorption temperature and the adsorbent in the second adsorption section is at the adsorption temperature; a blower for blowing air to the first and second adsorption sections via an inlet channel; an application section for applying the desorbed gas containing carbon dioxide desorbed from the first and second adsorption sections to cultivated plants; and an extraction section for combining extracted gas, obtained by extracting a portion of the air flowing through the inlet channel, with the desorbed gas. The extraction section has an extraction adjustment section for adjusting the degree of extraction. The control unit further controls the extraction adjustment unit so that the carbon dioxide concentration of the desorbed gas after the extraction gas has merged with the extraction gas reaches a predetermined concentration. [Effects of the Invention]

[0006] According to the present invention, CO2 can be efficiently applied to cultivated plants. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic block diagram showing an example of the main components of a carbon dioxide application device according to an embodiment of the present invention. [Figure 2] A block diagram schematically showing an example of the control configuration of the carbon dioxide application device shown in Figure 1. [Figure 3] This figure shows an example of the time-dependent changes in CO2 concentration and airflow rate of the gas flowing through each part of the carbon dioxide application device shown in Figure 1. [Figure 4] This figure shows a modified version of Figure 1 when a filter is installed in the application channel. [Figure 5] This figure shows a modified version of Figure 4, where extraction is performed from downstream of the airflow distribution mechanism. [Figure 6]A block diagram schematically showing an example of the control configuration of the carbon dioxide application device shown in Figure 5. [Figure 7] This figure shows a modified version of Figure 1, where a blower is provided for each suction part. [Figure 8] A block diagram schematically showing an example of the control configuration of the carbon dioxide application device shown in Figure 7. [Figure 9] This figure shows a modified version of Figure 7, where a filter is installed in the application channel. [Figure 10A] Figure 1 shows an example of the operating mode and blowing mode of the carbon dioxide application device. [Figure 10B] Figure 1 shows another example of the operating mode and blowing mode of the carbon dioxide application device. [Figure 10C] Figure 1 shows yet another example of the operating mode and blowing mode of the carbon dioxide application device. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to Figures 1 to 10C. The carbon dioxide application device according to the embodiment of the present invention is an agricultural DAC (Direct Air Capture) device that recovers CO2 from the air and applies it to cultivated plants. In the following, an example of recovering and applying CO2 from the ambient air (atmosphere) by TSA (Thermal Swing Adsorption) will be described in particular.

[0009] Such DAC devices inevitably consume energy, such as electricity, because they operate blowers, heaters, etc., to recover and apply CO2. On the other hand, since there is a limit to the amount of CO2 that cultivated plants can consume through photosynthesis, if CO2 is applied in excess of what can be consumed through photosynthesis, the excess CO2 will diffuse into the atmosphere without promoting the growth of the cultivated plants. In this case, the energy consumed for recovering and applying the excess CO2 is wasted. Therefore, in this embodiment, the carbon dioxide application device is configured as follows so that CO2 can be efficiently applied to cultivated plants by applying CO2 within the range that can be consumed through photosynthesis.

[0010] FIG. 1 is a block diagram schematically showing an example of the main configuration of a carbon dioxide application device (hereinafter referred to as the device) 100 according to an embodiment of the present invention, and FIG. 2 is a block diagram schematically showing an example of the control configuration of the device 100 in FIG. 1. As shown in FIGS. 1 and 2, the device 100 includes a plurality (two in the illustrated example) of adsorption units 1a, 1b, a blower 2, a plurality (two in the illustrated example) of heaters 3a, 3b, an air volume distribution mechanism 4, an application pipe 5, flow path switching mechanisms 6a, 6b, an air extraction adjustment unit 7, and a controller 10.

[0011] An adsorbent (or absorbent) is provided in each of the adsorption units 1a, 1b. The adsorbent is a solid material configured to adsorb (or absorb) CO2 at normal temperature and pressure and desorb CO2 when heated. For example, a porous material such as zeolite, an amine-based solid absorbent in which an amine-based compound is supported on a suitable carrier, etc. can be used. The adsorbent is, for example, configured in a granular form and filled in the adsorption units 1a, 1b. The adsorbent may be supported on a substrate having an appropriate shape such as a honeycomb shape, a mesh shape, a sheet shape, etc., and housed in the adsorption units 1a, 1b together with the substrate.

[0012] The blower 2 is connected to each of the adsorption units 1a, 1b via an inlet flow path P1 formed by an appropriate pipe, and blows the air in the surrounding environment to each of the adsorption units 1a, 1b via the inlet flow path P1. In other words, the blower 2 accelerates the air in the surrounding environment and supplies it to each of the adsorption units 1a, 1b in a state where the flow rate is increased. For example, when the device 100 is provided in an indoor plant factory, the air in the surrounding environment is air at room temperature (atmosphere). The air in the surrounding environment may be indoor air, may be air taken in from the outside, or may be air in which indoor air and air taken in from the outside are mixed. The blower 2 is controlled by the controller 10.

[0013] The heaters 3a and 3b are provided in the inlet passage P1 corresponding to the respective adsorption parts 1a and 1b. When the heaters 3a and 3b are on, the air blown from the blower 2 to the respective adsorption parts 1a and 1b is heated, whereby the adsorbent of each adsorption part 1a and 1b is heated up. When the heaters 3a and 3b are off, the air from the blower 2 is blown to the respective adsorption parts 1a and 1b without being heated. The heaters 3a and 3b are controlled by the controller 10.

[0014] Each of the heaters 3a and 3b is set to a set temperature (for example, about 70°C) higher than the room temperature (for example, about 20°C) which is the temperature of the surrounding environment. When the heaters 3a and 3b are turned on from the off state, the air blown from the blower 2 and flowing through the inlet passage P1 is heated from the room temperature to the set temperature and flows to the respective adsorption parts 1a and 1b, whereby the temperature of the adsorbent of each adsorption part 1a and 1b gradually rises. When the heaters 3a and 3b are turned off from the on state, the air blown from the blower 2 and flowing through the inlet passage P1 flows to the respective adsorption parts 1a and 1b at the room temperature without being heated, whereby the temperature of the adsorbent of each adsorption part 1a and 1b gradually decreases.

[0015] The air volume distribution mechanism 4 is provided in the inlet passage P1 upstream of the heaters 3a and 3b, and distributes the air blown from the blower 2 and flowing through the inlet passage P1 to the adsorption parts 1a and 1b via the heaters 3a and 3b. The air volume distribution mechanism 4 is controlled by the controller 10.

[0016] The application pipe 5 is composed of an appropriate pipe and is laid along the planting position of the cultivated plants. A plurality of local application holes 5a are formed in the upper surface in the gravity direction of the application pipe 5, and the application gas flowing through the application pipe 5 jets out from below toward the back of the leaves of the cultivated plants through the local application holes 5a.

[0017] The flow path switching mechanisms 6a and 6b are composed of three-way valves and are interposed between the adsorption units 1a and 1b and the application piping 5. The flow path switching mechanisms 6a and 6b are controlled by the controller 10 to either flow air with an increased CO2 concentration (desorbed gas) containing CO2 desorbed from the adsorbent material of the adsorption units 1a and 1b into the application piping 5, or release air with a decreased CO2 concentration (post-adsorption gas) after CO2 has been adsorbed by the adsorbent material of the adsorption units 1a and 1b into the atmosphere. Hereinafter, the application piping 5 and the flow path switching mechanisms 6a and 6b may be collectively referred to as the "application unit" that applies the desorbed gas to cultivated plants.

[0018] The airflow distribution mechanism 4, heaters 3a, 3b, adsorption units 1a, 1b, and flow path switching mechanisms 6a, 6b may be housed in a suitable enclosure CS. The enclosure CS is configured to detachably house the adsorption units 1a, 1b, allowing for periodic removal of the adsorption units 1a, 1b for maintenance such as regeneration or replacement of the adsorbent material. Furthermore, the enclosure CS is configured to be airtight so that the air blown and introduced from the blower 2 via the inlet flow path P1 flows through the airflow distribution mechanism 4, heaters 3a, 3b, adsorption units 1a, 1b, and flow path switching mechanisms 6a, 6b without leaking outside the enclosure CS.

[0019] One end of an extraction channel P2, which is constructed with appropriate piping, is connected to the inlet channel P1 upstream of heaters 3a and 3b, and a portion of the air flowing through the inlet channel P1 is extracted through the extraction channel P2. The other end of the extraction channel P2 is connected to an application channel P3 between the flow path switching mechanisms 6a and 6b and the application piping 5, and the air extracted from the inlet channel P1 (extracted gas) flows through the extraction channel P2 and merges with the desorbed gas flowing through the application channel P3. The desorbed gas, after merging with the extracted gas, flows into the application piping 5 as application gas and is ejected towards the cultivated plants through the local application holes 5a.

[0020] The extraction passage P2 is provided with an extraction adjustment unit 7 for adjusting the degree of extraction. The extraction adjustment unit 7 is an airflow adjustment mechanism having an adjustment valve, an orifice, or a blower. The extraction adjustment unit 7 is controlled by a controller 10. Hereinafter, the extraction passage P2 and the extraction adjustment unit 7 may be collectively referred to as the "extraction unit" that merges the extracted gas with the desorbed gas.

[0021] The controller 10 is composed of a computer having a processor such as a CPU, memory such as RAM and ROM, and other peripheral circuits, and controls each part of the device 100, which includes the blower 2, heaters 3a and 3b, air volume distribution mechanism 4, flow path switching mechanisms 6a and 6b, and extraction adjustment unit 7. More specifically, the controller 10 controls each part so that the operating mode of the device 100 alternately switches between a first mode in which suction occurs at the suction unit 1a and detachment occurs at the suction unit 1b, and a second mode in which detachment occurs at the suction unit 1a and suction occurs at the suction unit 1b. The switching of the operating mode is performed at predetermined intervals (for example, about 60 minutes).

[0022] In the first mode, the controller 10 turns off the heater 3a so that the adsorbent in the adsorption section 1a reaches an adsorption temperature close to room temperature, and turns on the heater 3b so that the adsorbent in the adsorption section 1b reaches a desorption temperature close to the set temperature of heaters 3a and 3b. The controller 10 also controls the flow path switching mechanism 6a so that the air with reduced CO2 concentration (post-adsorption gas) after CO2 has been adsorbed in the adsorption section 1a is released into the atmosphere, and controls the flow path switching mechanism 6b so that the desorbed gas containing CO2 desorbed in the adsorption section 1b flows into the application piping 5.

[0023] In the second mode, the controller 10 turns on the heater 3a so that the adsorbent in the adsorption section 1a reaches the desorption temperature, and turns off the heater 3b so that the adsorbent in the adsorption section 1b reaches the adsorption temperature. It also controls the flow path switching mechanism 6a so that the desorbed gas containing CO2 desorbed in the adsorption section 1a flows into the application piping 5, and controls the flow path switching mechanism 6b so that the air with reduced CO2 concentration due to CO2 adsorption in the adsorption section 1b is released into the atmosphere.

[0024] The controller 10 further controls the extraction adjustment unit 7 so that the CO2 concentration of the desorbed gas (applied gas) after the extraction gas has merged becomes a predetermined target application concentration. The controller 10 may control the extraction adjustment unit 7 to continuously adjust the degree of extraction according to the concentration of the desorbed gas before the extraction gas merges and the target application concentration, or it may control the extraction adjustment unit 7 to adjust the degree of extraction in steps. For example, the extraction adjustment unit 7 may simply be controlled to open and close the extraction flow path P2.

[0025] Figure 3 shows an example of the time evolution of CO2 concentration and airflow rate (target airflow rate) for the adsorbed gas, desorbed gas, extracted gas, and applied gas. The adsorbed gas is air that flows from the adsorption sections 1a and 1b on the side where adsorption occurs to the flow path switching mechanisms 6a and 6b, and whose CO2 concentration has decreased due to adsorption. The desorbed gas is air that flows from the adsorption sections 1a and 1b on the side where desorption occurs to the flow path switching mechanisms 6a and 6b, and whose CO2 concentration has increased due to the CO2 desorbed from the adsorbent. The extracted gas is air that is extracted from the inlet flow path P1 and flows through the extracted flow path P2, and has the same CO2 concentration as the ambient air (atmosphere) (approximately 400 ppm). The applied gas is the desorbed gas that flows through the applied flow path P3 after the extracted gas has merged with it.

[0026] As shown in Figure 3, on the adsorption side, in both the first and second modes, during the period immediately after mode switching when the adsorbent is cooled from the desorption temperature to the adsorption temperature, the adsorption rate relative to the desorption rate of CO2 gradually increases, and the CO2 concentration of the adsorbed gas gradually decreases. Subsequently, as the amount of CO2 adsorbed by the adsorbent gradually approaches saturation, CO2 adsorption gradually slows down, and the CO2 concentration of the adsorbed gas gradually increases, approaching the CO2 concentration in the atmosphere (approximately 400 ppm).

[0027] On the desorption side, in both the first and second modes, during the period immediately following mode switching when the adsorbent is heated from its adsorption temperature to its desorption temperature, the desorption rate relative to the CO2 adsorption rate gradually increases, and the CO2 concentration of the desorbed gas gradually rises. Subsequently, as the amount of CO2 adsorbed by the adsorbent gradually decreases, the amount of CO2 desorbed per unit time gradually decreases, and the CO2 concentration of the desorbed gas gradually decreases.

[0028] The controller 10 controls the blower 2 and the airflow distribution mechanism 4 to adjust the airflow rate of the air flowing to the adsorption-side adsorption sections 1a and 1b (equivalent to the airflow rate on the adsorption side and the airflow rate of the adsorbed gas) and the airflow rate of the air flowing to the desorption-side adsorption sections 1a and 1b (equivalent to the airflow rate on the desorption side and the airflow rate of the desorbed gas). More specifically, it considers the balance between the amount of CO2 adsorbed and desorbed in the first mode and the second mode, and adjusts the airflow rate on the desorption side (5 m in the example in Figure 3). 3 Airflow rate on the adsorption side relative to (45 m / h in the example in Figure 3) 3 The airflow distribution mechanism 4 is controlled so that the ratio ( / h) is 8 times or more (9 times in the example in Figure 3).

[0029] Furthermore, in order to ensure sufficient airflow for the desorbed gas so that it can be ejected towards the cultivated plants through the local application holes 5a, and to ensure sufficient flow velocity of the desorbed gas flowing through the application pipe 5, a sufficient airflow (50 m in the example in Figure 3) is provided. 3 The blower 2 is controlled to achieve a rate of / h). If the flow velocity of the desorbed gas flowing through the application pipe 5 is insufficient, the flow velocity of the desorbed gas flowing out from the local application hole 5a will be insufficient, and the desorbed gas will diffuse into the surrounding area instead of being ejected towards the cultivated plants above.

[0030] In the example shown in Figure 3, the CO2 concentration of the desorbed gas fluctuates within a range of approximately 1500 ppm to 3000 ppm. The amount of CO2 that cultivated plants can consume through photosynthesis varies depending on the variety, but is generally in the range of approximately 1000 ppm to 1500 ppm. The controller 10 controls the extraction adjustment unit 7 and adjusts the airflow rate (degree of extraction) of the extracted gas flowing through the extraction channel P2 so that the CO2 concentration of the applied gas becomes the target application concentration that cultivated plants can consume through photosynthesis (approximately 1200 ppm in the example shown in Figure 3).

[0031] More specifically, during periods when the CO2 concentration of the desorbed gas is increasing, the extraction adjustment unit 7 is controlled so that the airflow rate of the extracted gas gradually increases, and during periods when the CO2 concentration of the desorbed gas is decreasing, the extraction adjustment unit 7 is controlled so that the airflow rate of the extracted gas gradually decreases. Also, the airflow rate of the desorbed gas (5 m in the example in Figure 3) 3 The airflow rate of the extracted gas (0 m / h in the example in Figure 3) is relative to the airflow rate of the extracted gas (0 m / h). 3 From about / h to 10m 3 The extraction adjustment unit 7 is controlled so that the rate (approximately / h) is less than or equal to twice the original rate. Note that the actual airflow rate of the blower 2 increases or decreases in accordance with the increase or decrease in the airflow rate of the extracted gas, even when the energy consumed by the blower 2 is constant, such as when the blower 2 is driven at a constant voltage with a constant target airflow rate. In other words, as the airflow rate of the extracted gas increases, the airflow resistance (airflow resistance) of the inlet passage P1 decreases, and the actual airflow rate of the blower 2 increases.

[0032] When the device 100 is installed in an indoor plant factory, for example, if the temperature and CO2 concentration of the air blown from the blower 2 are generally constant, the time change in the CO2 concentration of the desorbed gas, as shown in Figure 3, will be generally constant. Therefore, the controller 10 can control the extraction adjustment unit 7 according to the characteristics of the extraction gas airflow rate (target airflow rate) for a predetermined time. When the device 100 is installed outdoors or exhaust gas is used, for example, if the temperature and CO2 concentration of the air blown from the blower 2 change, the CO2 concentration of the applied gas may be detected, and the extraction adjustment unit 7 may be feedback controlled based on the detection result. In this case, for example, a CO2 concentration (partial pressure) sensor can be installed in the application flow path P3 to detect the CO2 concentration of the applied gas, and the extraction adjustment unit 7 can be controlled so that the detected CO2 concentration of the applied gas becomes the target application concentration.

[0033] Thus, the device 100 can continuously obtain desorbed gas by adsorbing and desorbing CO2 using multiple adsorption units 1a and 1b, and can apply it to cultivated plants. Therefore, it is suitable for use in plant factories and the like that operate for long periods of time (for example, about 16 hours a day). Furthermore, since the device 100 applies the desorbed gas to cultivated plants on the spot without storing it, storage facilities are unnecessary, allowing the entire device to be made smaller and simpler, and reducing the cost of CO2 application. Moreover, when using ambient air, the entire device can be made even smaller and simpler, and the device 100 can be operated continuously as needed, regardless of the supply status of the raw material gas.

[0034] Furthermore, since the device 100 dilutes the desorbed gas with extraction gas and applies it to cultivated plants as a CO2 concentration that can be consumed by photosynthesis, there is no waste of desorbed gas, and the energy consumed by the blower 2 and heaters 3a and 3b is not wasted. In addition, since the CO2 concentration of the desorbed gas (applied gas) is maintained within a range that can be used for photosynthesis in cultivated plants, it is safe for workers around the cultivated plants. When ambient air is used, the composition of the desorbed gas (applied gas) is equivalent to that of the atmosphere, and it does not contain harmful components as when exhaust gas is used, making it safe.

[0035] Since the extracted gas flows from downstream of the blower 2, bypassing the adsorption sections 1a and 1b, and into the application channel P3, it does not experience pressure loss due to passing through the adsorbent packed in the adsorption sections 1a and 1b, thus minimizing the energy consumed by the blower 2 for extraction. Furthermore, the extracted gas does not pass through the heaters 3a and 3b and flows into the application channel P3 at room temperature without being heated. As a result, the temperature of the application gas is lower than that of the desorption gas, reaching a temperature suitable for application to cultivated plants (for example, around 25°C). For example, the air from the blower 2 is heated to about 70°C by the heaters 3a and 3b on the desorption side, cooled to around 40°C by endothermic heat during CO2 desorption in the adsorption sections 1a and 1b on the desorption side, and then further cooled to about 25°C by the room temperature extracted gas that joins it.

[0036] Figure 4 shows a modified version of Figure 1 when a filter 8 is provided in the application channel P3. Due to deterioration over time, some of the adsorbent material packed in the adsorption sections 1a and 1b may flow out of the adsorption sections 1a and 1b along with the desorbed gas. In the modified version of Figure 4, the application section is configured such that a filter 8 made of a material that does not affect the human body, such as an activated carbon filter, is provided in the application channel P3 to remove foreign matter such as adsorbent material from the desorbed gas before it is applied to the cultivated plants as an application gas. In this case, the downstream side of the extraction channel P2 is connected to the application channel P3 downstream of the filter 8, and the extraction gas is merged with the desorbed gas downstream of the filter 8. Therefore, the extraction gas does not suffer pressure loss due to passing through the filter 8, and even when the filter 8 is provided, the energy consumed by the blower 2 for extraction can be minimized.

[0037] Figure 5 shows a modified version of Figure 4 when extraction is performed downstream of the airflow distribution mechanism 4, and Figure 6 is a schematic block diagram showing an example of the control configuration of the device 100 in Figure 5. In the modified versions of Figures 5 and 6, the upstream side of the extraction flow path P2a is connected between the airflow distribution mechanism 4 and the heater 3a, and a portion of the air flowing from the airflow distribution mechanism 4 to the heater 3a and the adsorption unit 1a is extracted through the extraction flow path P2a. Similarly, the upstream side of the extraction flow path P2b is connected between the airflow distribution mechanism 4 and the heater 3b, and a portion of the air flowing from the airflow distribution mechanism 4 to the heater 3b and the adsorption unit 1b is extracted through the extraction flow path P2b.

[0038] In this case, in the first mode, the controller 10 controls the extraction adjustment unit 7a to close the extraction flow path P2a on the adsorption side, and controls the extraction adjustment unit 7b on the desorption side so that the CO2 concentration of the applied gas becomes the target application concentration. Similarly, in the second mode, the controller 10 controls the extraction adjustment unit 7b to close the extraction flow path P2b on the adsorption side, and controls the extraction adjustment unit 7a on the desorption side so that the CO2 concentration of the applied gas becomes the target application concentration.

[0039] Figure 7 shows a modified version of Figure 1 in which blowers 2a and 2b are provided corresponding to each suction part 1a and 1b, and Figure 8 is a schematic block diagram showing an example of the control configuration of the device 100 in Figure 7. In the modified versions of Figures 7 and 8, a blower 2a is provided to supply air to the heater 3a and suction part 1a, and a blower 2b is provided to supply air to the heater 3b and suction part 1b. In this case, the air volume distribution mechanism 4 is not provided.

[0040] The upstream side of the extraction air passage P2a is connected to the inlet passage P1a between the blower 2a and the heater 3a, and a portion of the air flowing from the blower 2a to the heater 3a and the adsorption unit 1a is extracted through the extraction air passage P2a. Similarly, the upstream side of the extraction air passage P2b is connected to the inlet passage P1b between the blower 2b and the heater 3b, and a portion of the air flowing from the blower 2b to the heater 3b and the adsorption unit 1b is extracted through the extraction air passage P2b. In this case, the controller 10 controls each of the blowers 2a and 2b to adjust the airflow rate to each of the adsorption units 1a and 1b.

[0041] Figure 9 shows a modified version of Figure 7, where a filter 8 is provided in the application channel P3. In the modified version of Figure 9, the application section is configured such that a filter 8 is provided in the application channel P3, and the downstream sides of the extraction channels P2a and P2b are connected to the application channel P3 downstream of the filter 8.

[0042] Figures 10A to 10C show examples of operating modes and fanning modes of the device 100, and explain the on / off switching of the LED light source that irradiates light onto each part of the device 100 installed in the plant factory and the cultivated plants. The LED light source is turned on when the plant factory is in operation (16 hours a day in the illustrated example) and turned off when the plant factory is not in operation (8 hours a day in the illustrated example). When the LED light source is on, photosynthesis occurs in the cultivated plants, and when the LED light source is off, photosynthesis does not occur in the cultivated plants, and only respiration occurs.

[0043] As shown in Figures 10A to 10C, when the LED light source is turned on and the cultivated plants are performing photosynthesis, the fans 2, 2a, 2b and heaters 3a, 3b are turned on, and the device 100 operates as a DAC device, supplying the cultivated plants with air (applied gas) at a high CO2 concentration. During operation as a DAC device, the operating mode of the device 100 is switched at predetermined intervals (1 hour in the illustrated example) between a first mode in which heater 3a is turned off and heater 3b is turned on, and a second mode in which heater 3a is turned on and heater 3b is turned off. When the LED light source is turned off and the cultivated plants are only respiring and not performing photosynthesis, heaters 3a and 3b are turned off, and the device 100 stops operating as a DAC device.

[0044] When the device 100 stops operating as a DAC device (16 hours after the first start of operation), the amount of CO2 adsorbed by the adsorption section 1a, which was the desorption side in the previous operating mode (second mode 15-16 hours later), is small, while the amount of CO2 adsorbed by the adsorption section 1b, which was the adsorption side, is large, resulting in a saturated or near-saturated state.

[0045] As shown in Figures 10A to 10C, while the device 100 is stopped operating as a DAC device (after 16 to 24 hours), by switching to a fan mode in which only the fans 2, 2a, and 2b are turned on while the heaters 3a and 3b are turned off for at least one cycle (1 hour in the illustrated example) corresponding to one operating mode, all adsorption parts 1a and 1b can be brought to a saturated or near-saturated state.

[0046] In the example in Figure 10A, the fan mode is executed in the cycle immediately before the device 100 starts its second operation as a DAC device (23-24 hours later). In the example in Figure 10B, the fan mode is executed in the cycle immediately after the device 100 stops its first operation as a DAC device (16-17 hours later). In this fan mode, the controller 10 sets the airflow rate of the adsorption part 1a, which was the detachment side in the previous operation mode (the second mode 15-16 hours later), to be equivalent to the airflow rate of the adsorption side in each operation mode (for example, 45 m³). 3Control the air volume distribution mechanism 4 so that it becomes ( / h). Also, the air volume of the adsorption part 1b which was the adsorption side in the immediately previous operation mode is made equal to the air volume on the desorption side in each operation mode (for example, 5 m 3 Control the air volume distribution mechanism 4 so that it becomes ( / h).

[0047] As a result, at the start of the second and subsequent operations as the DAC device of the apparatus 100, all the adsorption parts 1a and 1b can be set in a saturated state or a state close to saturation. In this case, as immediately after the start of the first mode shown in FIG. 3, the CO2 concentration of the desorbed gas does not become insufficient, and desorbed gas and application gas with a sufficient CO2 concentration can be obtained from immediately after the start of the operation (24 hours later in FIGS. 10A to 10C) and supplied to the cultivated plants. Further, the blowing mode using only the blowers 2, 2a, and 2b with extremely small energy consumption compared to the heaters 3a and 3b can be executed with extremely small energy consumption compared to the operation mode.

[0048] In the example of FIG. 10C, the blowing mode is executed from when the apparatus 100 stops the first operation as the DAC device until the start of the second operation (16 to 24 hours later). In the blowing mode in this case, the controller 10 makes the air volume of one of the adsorption parts 1a and 1b equal to the air volume on the adsorption side in each operation mode (for example, 45 m 3 / h), and controls the air volume distribution mechanism 4 so that the air volume of the other becomes equal to the air volume on the desorption side in each operation mode (for example, 5 m 3 / h).

[0049] Furthermore, the controller 10 controls the flow path switching mechanisms 6a and 6b so that the air passing through one of the adsorption parts 1a and 1b is released to the atmosphere, and the air passing through the other flows into the application pipe 5. More specifically, the air passing through the adsorption parts 1a and 1b on the side with a large air volume (for example, 45 m 3 / h) is released to the atmosphere, and the flow path switching mechanisms 6a and 6b are controlled so that the air passing through the adsorption parts 1a and 1b on the side with a small air volume (for example, 5 m 3 / h) flows into the application pipe 5.

[0050] In this case, even when the cultivated plants are only respiring and not performing photosynthesis, a constant volume of air is supplied through the application pipe 5 and ejected towards the underside of the leaves of the cultivated plants through the local application holes 5a. This blows away the CO2 released by the respiration of the cultivated plants, preventing it from accumulating around the plants and thereby promoting the respiration of the cultivated plants.

[0051] This embodiment can provide the following effects and advantages. (1) The apparatus 100 includes adsorption sections 1a and 1b, each having an adsorbent configured to adsorb CO2 at a predetermined adsorption temperature and desorb CO2 at a desorption temperature higher than the adsorption temperature; heaters 3a and 3b for adjusting the respective temperatures of the adsorption sections 1a and 1b; a first mode for controlling the heaters 3a and 3b so that the adsorbent in adsorption section 1a reaches the adsorption temperature and the adsorbent in adsorption section 1b reaches the desorption temperature; and a second mode for controlling the heaters 3a and 3b so that the adsorbent in adsorption section 1a reaches the desorption temperature and the adsorbent in adsorption section 1b reaches the adsorption temperature. The system includes a controller 10 that alternately switches between a second operating mode and a second operating mode, blowers 2, 2a, and 2b that supply air to the adsorption units 1a and 1b via the inlet flow path P1, an application unit (application piping 5, flow path switching mechanisms 6a, 6b, and filter 8) that applies the desorbed gas containing CO2 desorbed from the adsorption units 1a and 1b to cultivated plants, and an extraction unit (extraction flow path P2 and extraction adjustment units 7, 7a, and 7b) that extracts a portion of the air flowing through the inlet flow path P1 and combines it with the desorbed gas (Figures 1, 2, 4 to 9). The extraction unit has an extraction adjustment unit 7 that adjusts the degree of extraction. The controller 10 further controls the extraction adjustment unit 7 so that the CO2 concentration of the desorbed gas after the extraction gas has been combined reaches a predetermined target application concentration (Figure 3).

[0052] By diluting the desorbed gas with extraction gas and maintaining the CO2 concentration of the applied gas at a target application concentration within the range usable for photosynthesis in cultivated plants, the recovered CO2 can be efficiently applied to cultivated plants without waste. Furthermore, by diverting the extracted gas, which is air blown from blowers 2, 2a, and 2b and flowing through inlet channels P1, P1a, and P1b, to the desorbed gas by bypassing the adsorption sections 1a and 1b, which have high pressure loss, extraction can be performed without increasing the power consumption of blower 2. In addition, by diluting the relatively high-temperature desorbed gas with the relatively low-temperature extraction gas, the temperature of the applied gas can be lowered to a temperature suitable for application to cultivated plants.

[0053] (2) Heaters 3a and 3b are installed in the inlet passages P1, P1a, and P1b and heat the air blown from the blowers 2, 2a, and 2b (Figures 1, 4, 5, 7, and 9). The extraction section extracts a portion of the air from the inlet passages P1, P1a, and P1b upstream of the heaters 3a and 3b. By having the extracted gas bypass the heaters 3a and 3b and merge with the desorbed gas, the power consumption of the blowers 2, 2a, and 2b can be reduced, and the temperature of the applied gas can be lowered.

[0054] (3) The application section further includes a filter 8 that removes foreign matter from the desorbed gas (Figures 4, 5, and 9). The extraction section merges the extracted gas with the desorbed gas downstream of the filter 8. That is, the desorbed gas that has passed through the adsorption sections 1a and 1b may contain foreign matter such as adsorbent material, so it is allowed to pass through the filter 8, while the extracted gas, which is air extracted from the inlet passage P1, does not pass through the filter 8 because it does not likely contain foreign matter such as adsorbent material. In this way, by bypassing the filter 8, which has a large pressure loss, and merging the extracted gas with the desorbed gas, extraction can be performed without increasing the power consumption of the blower 2.

[0055] (4) In both the first and second modes, the controller 10 controls the extraction adjustment unit 7 so that the degree of extraction gradually increases during the period when the adsorbent is heated from the adsorption temperature to the desorption temperature and the CO2 concentration of the desorbed gas increases, and after the adsorbent has been heated to the desorption temperature, the extraction adjustment unit 7 controls the degree of extraction gradually decreases during the period when the CO2 adsorbed on the adsorbent decreases and the CO2 concentration of the desorbed gas decreases (Figure 3). In this way, by adjusting the degree of extraction in accordance with the change in the CO2 concentration of the desorbed gas, the CO2 concentration of the applied gas can be maintained at a target application concentration within the range that can be used for photosynthesis of cultivated plants.

[0056] (5) In the first mode, the airflow rate of the air supplied to the adsorption unit 1a (adsorption side airflow rate) is 8 times or more the airflow rate of the air supplied to the adsorption unit 1b (desorption side airflow rate), and the airflow rate of the extracted gas is 2 times or less the airflow rate of the air supplied to the adsorption unit 1b (desorption side airflow rate) (Figure 3). In the second mode, the airflow rate of the air supplied to the adsorption unit 1b (adsorption side airflow rate) is 8 times or more the airflow rate of the air supplied to the adsorption unit 1a (desorption side airflow rate), and the airflow rate of the extracted gas is 2 times or less the airflow rate of the air supplied to the adsorption unit 1a (desorption side airflow rate) (Figure 3).

[0057] Specifically, as shown in Figure 3, if the CO2 concentration of the desorbed gas fluctuates between approximately 1500 ppm and 3000 ppm in each operating mode, the airflow rate from the adsorption side should be set to at least eight times that of the desorbing side, and the extraction airflow rate should be set to at least twice that of the desorbing side. This allows the CO2 concentration of the applied gas to be maintained at approximately 1200 ppm (target application concentration), which is within the range that can be used for photosynthesis in cultivated plants.

[0058] (6) The extraction section further has extraction passages P2, P2a, and P2b through which the extracted gas flows (Figures 1, 4, 5, 7, and 9). The extraction adjustment sections 7, 7a, and 7b are airflow adjustment mechanisms or blowers provided in the extraction passages P2, P2a, and P2b. When a portion of the air blown and accelerated by the blowers 2, 2a, and 2b is extracted while adjusting the degree of extraction using the extraction adjustment sections 7, 7a, and 7b, which are airflow adjustment mechanisms having adjustment valves, orifices, etc., the extracted gas is not further accelerated in the extraction section. Also, even when the degree of extraction is adjusted using the extraction adjustment sections 7, 7a, and 7b, which are blowers, the additional acceleration of the extracted gas in the extraction section can be minimized. In either case, the energy consumed by the blowers 2, 2a, and 2b is not wasted, and the energy consumption for extraction can be minimized.

[0059] In the above embodiment, an example was described in which CO2 from the ambient air (atmosphere) is recovered by TSA and applied. However, CO2 recovery may also be performed from exhaust gas or by other methods such as PSA (Pressure Swing Adsorption). In the above embodiment, an example using two adsorption units 1a and 1b was described in Figure 1, but three or more adsorption units may be used. In the above embodiment, an example was described in which the air blown to the adsorption units 1a and 1b is heated by heaters 3a and 3b. However, the temperature control unit that adjusts the temperature of each adsorption unit is not limited to this. For example, heaters may be provided at each adsorption unit 1a and 1b to heat the adsorbent material of each adsorption unit 1a and 1b.

[0060] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other.

[0061] 1a,1b Adsorption section, 2,2a,2b Blower, 3a,3b Heater, 4 Air volume distribution mechanism, 5 Application piping, 5a Local application hole, 6a,6b Flow path switching mechanism, 7,7a,7b Extraction adjustment section, 8 Filter, 10 Controller, 100 Carbon dioxide application device (device), CS Housing, P1,P1a,P1b Inlet flow path, P2,P2a,P2b Extraction flow path, P3 Application flow path

Claims

1. A first adsorption section and a second adsorption section each have an adsorbent configured to adsorb carbon dioxide at a predetermined adsorption temperature and to desorb carbon dioxide at a desorption temperature higher than the adsorption temperature, A temperature adjustment unit that adjusts the temperature of the first adsorption unit and the second adsorption unit, A control unit alternately switches between two operating modes: a first mode in which the temperature control unit controls the temperature control unit so that the adsorbent in the first adsorption unit reaches the adsorption temperature and the adsorbent in the second adsorption unit reaches the desorption temperature, and a second mode in which the temperature control unit controls the temperature control unit so that the adsorbent in the first adsorption unit reaches the desorption temperature and the adsorbent in the second adsorption unit reaches the adsorption temperature. A blower that blows air to the first adsorption section and the second adsorption section via an inlet passage, An application unit for applying the desorbed gas containing carbon dioxide desorbed from the first adsorption unit and the second adsorption unit to cultivated plants, The system includes an extraction section that extracts a portion of the air flowing through the inlet passage and combines the extracted gas with the desorbed gas, The extraction unit has an extraction adjustment unit for adjusting the degree of extraction. The carbon dioxide application device is characterized in that the control unit further controls the extraction adjustment unit so that the carbon dioxide concentration of the desorbed gas after the extraction gas has merged becomes a predetermined concentration.

2. In the carbon dioxide application device according to claim 1, The temperature control unit is a heater provided in the inlet passage that heats the air blown from the blower, The carbon dioxide application device is characterized in that the extraction unit extracts a portion of the air from the inlet passage upstream of the temperature control unit.

3. In the carbon dioxide application device according to claim 1 or 2, The application unit further includes a filter for removing foreign matter from the desorbed gas. The carbon dioxide application device is characterized in that the extraction unit combines the extracted gas with the desorbed gas downstream of the filter.

4. In the carbon dioxide application device according to claim 1 or 2, A carbon dioxide application device characterized in that the control unit controls the extraction adjustment unit in each of the first and second modes such that the degree of extraction gradually increases during the period when the adsorbent is heated from the adsorption temperature to the desorption temperature and the carbon dioxide concentration of the desorbed gas increases, and the extraction adjustment unit controls the degree of extraction gradually decreases during the period when the carbon dioxide adsorbed on the adsorbent decreases and the carbon dioxide concentration of the desorbed gas decreases after the adsorbent has been heated to the desorption temperature.

5. In the carbon dioxide application device according to claim 1 or 2, In the first mode, the airflow rate supplied to the first adsorption unit is 8 times or more the airflow rate supplied to the second adsorption unit, and the airflow rate of the extracted gas is 2 times or less the airflow rate supplied to the second adsorption unit. A carbon dioxide application device characterized in that, in the second mode, the airflow rate of the air supplied to the second adsorption unit is eight times or more the airflow rate of the air supplied to the first adsorption unit, and the airflow rate of the extracted gas is twice or less the airflow rate of the air supplied to the first adsorption unit.

6. In the carbon dioxide application device according to claim 1 or 2, The extraction unit further has an extraction passage through which the extracted gas flows, The carbon dioxide application device is characterized in that the extraction adjustment unit is an airflow adjustment mechanism or blower provided in the extraction flow path.

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