A device and method for capturing carbon dioxide to improve crop photosynthetic efficiency and quality.

Abstract

This invention discloses a device and method for capturing carbon dioxide to improve crop photosynthetic efficiency and quality, belonging to the field of facility agriculture technology. The device includes an exhaust device, a drying pipe, a main pipeline, fixing components, and a power supply component. The main pipeline is set inside the facility cultivation environment, with an opening at the top and an opening cover that can be slidably installed to the opening by external force. From bottom to top, the bottom is provided with a heating component, an adsorption bed, and an adsorbent. The device mainly relies on the adsorption and desorption of the adsorbent to enrich the CO2 in the facility cultivation environment. Moreover, the device is energy-saving and environmentally friendly, simple in structure, easy to install and operate, requires no manpower, occupies a small area, can be used for a long time in a cyclical manner, and meets the needs of green agriculture. Under specific conditions, the device of this invention can significantly improve the chlorophyll content, net photosynthetic rate, and soluble sugars and carotenoids of facility horticultural crops.

Description

Technical Field

[0001] This invention belongs to the field of facility agriculture technology, specifically relating to a device and method for capturing carbon dioxide to improve crop photosynthetic efficiency and quality. Background Technology

[0002] Against the backdrop of global warming and accelerating population growth, agricultural production faces the dual challenges of "improving quality and efficiency" and "green development." Facility agriculture breaks down the limitations imposed by climate, soil, and water resources on crop cultivation, playing a vital role in ensuring year-round vegetable supply, increasing land productivity, and boosting farmers' income. However, due to crop photosynthesis, dense planting methods, and enclosed environments, CO2 deficiency is a common problem in agricultural facilities. Daytime CO2 concentrations inside greenhouses / sheds are often only 100–200 μmol / mol. -1 It is far below the 700–1000 μmol / mol required for the growth of major greenhouse crops such as solanaceous vegetables and melons. -1 This severely limits the high quality and high yield of greenhouse crops.

[0003] To meet the carbon requirements of crop growth, CO2 enrichment is necessary in facility agriculture. Currently, commonly used CO2 enrichment technologies include fossil fuel combustion, composting, and chemical reactions. These methods all generate new CO2 to supply crops, increasing the pressure on agricultural carbon emissions and having drawbacks such as high energy, material, and labor inputs, which contradicts the development requirements of "green agriculture."

[0004] With the development of carbon capture technology in the industrial sector, the conversion of captured CO2 into products beneficial to humankind has attracted considerable attention. Utilizing greenhouse crop production to reuse captured CO2 can improve crop productivity while effectively reducing carbon emissions and increasing carbon sequestration, thus promoting sustainable agricultural development. However, methods commonly used in industry to regulate CO2 adsorption and desorption processes, such as temperature swing, pressure swing, and humidity swing, are not suitable for agricultural production environments. The abundant water vapor and dust in crop cultivation environments, as well as the uneven CO2 concentration in the microenvironment, also limit the functionality and effective utilization of CO2 capture materials.

[0005] Chinese patent document CN1457642A discloses a method for improving plant photosynthetic yield, enhancing drought resistance, and controlling pests and diseases using a carbon dioxide adsorbent. This method involves spraying a CO2 adsorbent, which selectively adsorbs carbon dioxide, onto the plants, forming a high-concentration CO2 gas layer on the plant surface. This increases the photosynthetic rate, reduces transpiration intensity, and improves the plant's drought resistance and water use efficiency. However, in this invention, the carbon dioxide adsorbent needs to be sprayed directly onto the plants, the number of sprays needs to increase with crop growth, and it cannot be recycled.

[0006] Chinese patent document CN108031238A discloses a device for capturing atmospheric carbon dioxide for use in facility agriculture. The device includes an external pipeline connected to a greenhouse, on which are installed an adsorption-desorption bed, a first valve, a second valve, a blower, a first CO2 concentration detection device, a second CO2 concentration detection device, and a temperature control device. This device captures CO2 from the air and stores it in the adsorption-desorption bed. During desorption, the collected CO2 enters the greenhouse. A third CO2 concentration detection device monitors the CO2 concentration inside the greenhouse to ensure it meets the needs of the crops. However, this invention requires a large space within the agricultural facility, the adsorption-desorption bed is located outside the greenhouse, the operation is complex, energy consumption is high, and the adsorption airflow lacks a pre-drying treatment device, making it impossible to guarantee the adsorption performance and reusability stability of the adsorbent. Summary of the Invention

[0007] This invention provides a device for capturing carbon dioxide to improve crop photosynthetic efficiency and quality. The device is energy-saving and environmentally friendly, simple in structure, easy to install and operate, requires no manpower, occupies a small area, can be used for a long time in a circular manner, meets the needs of green agriculture, and has a good effect on enriching CO2 in facility cultivation environments.

[0008] The specific technical solution adopted is as follows:

[0009] A device for capturing carbon dioxide to improve crop photosynthetic efficiency and quality includes: an air extraction device, a drying tube, a main pipe, a fixing component, and a power supply component;

[0010] The extraction device is used to drive the gas through the drying tube into the main pipeline;

[0011] The drying pipe is used to dry the intake air and deliver the dried gas to the main pipeline;

[0012] The main pipeline is located inside the facility cultivation environment. It has an opening at the top and an opening cover that can be slidably installed to the opening by external force. From bottom to top, the bottom is provided with heating components, an adsorption bed and an adsorbent.

[0013] The heating element is used to heat the adsorbent on the adsorption bed to release the adsorbed CO2; the adsorption bed is fixed on the inner wall of the main pipe; the adsorbent is used to adsorb CO2 in the dried gas and release it into the facility cultivation environment, and 13X zeolite molecular sieve or CHA zeolite molecular sieve is selected.

[0014] The fixing component is used to fix the main pipe;

[0015] The power supply component is used to supply power to the device.

[0016] The extraction device is used to drive CO2-containing gas through the drying pipe into the main pipeline, and can be a fan or an air pump; for ease of application, the extraction device is used to drive the atmosphere outside the facility cultivation environment into the drying pipe.

[0017] Preferably, the drying tube contains 3A molecular sieve or color-changing silica gel for drying the intake air; drying the intake air can reduce the competition of moisture for CO2 adsorption and the damage to the zeolite structure, thereby improving the adsorbent's CO2 adsorption and desorption capacity and reusability.

[0018] Preferably, the main pipe also includes a dustproof membrane covering the adsorbent. The dustproof membrane is preferably made of non-woven fabric to avoid the influence of dust on the adsorption capacity of the adsorbent.

[0019] Preferably, the inner wall of the main pipe is also provided with a snap-fit ​​joint that cooperates with and fixes the adsorption bed, which is used to fix the adsorption bed. The snap-fit ​​method facilitates the use of the adsorption bed and the replacement of the adsorbent, and is easier to operate.

[0020] Preferably, the adsorbent is CHA zeolite molecular sieve. Zeolite molecular sieves adsorb and desorb CO2 based on physical processes. CHA zeolite molecular sieves have a high silica-alumina ratio, good hydrophobic properties, and a unique pore structure, thus exhibiting excellent reusability. Even after multiple uses, they still maintain excellent CO2 adsorption and release characteristics.

[0021] Preferably, the power supply component is a solar panel.

[0022] The present invention also provides a method for improving crop photosynthetic efficiency and quality by capturing carbon dioxide using the aforementioned device, specifically comprising the following steps:

[0023] (1) Place the main pipe in the device near the canopy of the facility horticulture crop, close the opening cover of the main pipe, close the heating component, turn on the exhaust device, and let the gas be introduced into the main pipe through the drying pipe. The adsorbent captures CO2 until saturation, and the CO2 adsorption process is completed.

[0024] (2) Open the opening cover of the main pipeline, turn on the heating component, turn off the exhaust device, and release the CO2 captured by the adsorbent into the facility cultivation environment.

[0025] By fixing the main pipeline near the canopy of the greenhouse horticulture crops, CO2 is enriched in the microenvironment around the canopy, avoiding ineffective CO2 application and improving CO2 utilization efficiency.

[0026] Preferably, the CO2 adsorption using the device is performed during nighttime or midday when photosynthesis is weaker. The CO2 adsorption process is completed during the above time period, and the gas after CO2 adsorption can be directly discharged into the facility cultivation environment. This low CO2 concentration gas has little impact on plant photosynthesis and is beneficial to respiration.

[0027] Preferably, the amount of adsorbent used is 10-1000 g / m³, based on the volume of the greenhouse cultivation environment. 3 .

[0028] Preferably, in step (1), the adsorbent captures CO2 for 2-4 hours; in step (2), the temperature of the heating element is controlled at 50-200°C, and the desorption time is more than 1 hour.

[0029] More preferably, the temperature of the heating element is controlled at 80-120°C. Too high a temperature will lead to increased energy consumption, while too low a temperature will result in insufficient CO2 release.

[0030] Since the high humidity environment in the facility cultivation environment will affect the adsorption performance of the adsorbent for CO2, the adsorbent needs to be regenerated by high temperature drying after each 4-7 reuses before it can be used again. The high temperature drying and regeneration conditions are 100-300℃ for 1-48 hours.

[0031] Preferably, the facility-grown horticultural crop is tomato.

[0032] A further preferred method is to fix the main pipeline near the tomato canopy, using an adsorbent dosage of 50-100 g / m². 3 Operating the device under the above methods and conditions allows the CHA zeolite molecular sieve to capture CO2 for 2-4 hours to complete the CO2 adsorption process, followed by desorption at 80-120℃ for more than 1 hour; this can increase the CO2 concentration near the plant canopy by 100-1500 μmol / mol. -1 After long-term application of this method during the tomato growth period, compared with the control group, the experimental group showed significant improvements in chlorophyll content, net photosynthetic rate, and the content of quality components such as soluble sugar and carotenoids in the fruit. Specifically, the chlorophyll content of the plants increased by 50-80%, the net photosynthetic rate increased by 60-90%, the soluble sugar content of the fruit increased by 30-100%, and the carotenoid content increased by 20-50%.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) By designing a specific main pipeline and selecting 13X zeolite molecular sieve or CHA zeolite molecular sieve, this invention has constructed a device for capturing carbon dioxide to improve crop photosynthetic efficiency and quality. This device is energy-saving and environmentally friendly, simple in structure, easy to install and operate, requires no manpower, occupies a small area, can be used for a long time in a circular manner, meets the needs of green agriculture, is suitable for a variety of cultivation environments, and has a good CO2 enrichment effect on facility cultivation environments.

[0035] (2) Under specific conditions, the device of the present invention can improve the CO2 enrichment effect and the crop's CO2 utilization efficiency, and can increase the CO2 concentration near the plant canopy by 100-1500 μmol / mol. -1 Furthermore, long-term use during the tomato growing season can significantly increase the chlorophyll content, net photosynthetic rate, and soluble sugars and carotenoids in greenhouse horticultural crops.

[0036] (3) CHA zeolite molecular sieve has a stronger CO2 desorption capacity and better reusability than other zeolite molecular sieves. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of the device for capturing carbon dioxide to improve crop photosynthetic efficiency and quality in this invention.

[0038] Figure 2 The diagram shows the cross-sectional structure of the main pipeline, where A represents the CO2 desorption process and B represents the CO2 adsorption process.

[0039] Figure 3 The CO2 release curves are for the adsorbent and control materials.

[0040] Figure 4 The study investigated the effects of using this device in a protected cultivation environment on the chlorophyll content and net photosynthetic rate of 'Ailsa' tomato seedlings. Here, A represents the SPAD value, B represents the net photosynthetic rate, and a and b indicate that the differences between different treatments at the 5% level are significant.

[0041] Figure 5 This study investigated the changes in soluble sugar and carotenoid content in 'Ailsa' tomatoes after long-term use of this device during the tomato growing season. Here, A represents soluble sugar content and B represents carotenoid content; a and b indicate significant differences between different treatments at the 5% level.

[0042] Reference numerals: 1-Inlet pipe, 2-Outlet pipe, 3-Extraction device, 4-Power supply component, 5-Main pipe, 6-Drying pipe, 7-Dustproof membrane, 8-Adsorbent, 9-Adsorption bed, 10-Heating component, 11-Fixing component. Detailed Implementation

[0043] The present invention will be further illustrated below with reference to the embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] The device and its usage method described in Example 1

[0045] like Figure 1 As shown, the device for capturing carbon dioxide to improve crop photosynthetic efficiency and quality in this invention includes: an air extraction device 3, a drying tube 6, a main pipe 5, a fixing component 11 and a power supply component 4, an air inlet pipe 1 and an air outlet pipe 2.

[0046] The exhaust device 3 is used to drive the air from outside the cultivation environment into the drying pipe 6 through the air inlet pipe 1; specifically, an air pump is selected. The drying pipe 6 is filled with 20g of color-changing silica gel (replaced after each adsorption-desorption cycle of 5-7 times, when the color completely changes from blue to red), used for drying the air intake, and transporting the dried gas to the main pipe 5. The main pipe 5 is located inside the cultivation environment, such as... Figure 2 As shown in A and B, the top of the main pipe 5 is provided with an opening and an opening cover that can be slidably installed to the opening by the action of a mechanical arm. The material is PVC pipe. From bottom to top, the bottom is provided with a heating element 10, an adsorption bed 9, an adsorbent 8 and a dustproof membrane 7.

[0047] The heating element 10 is used to heat the adsorbent 8 on the adsorption bed 9 to release the adsorbed CO2. The heating element includes a silicone rubber wire with a cross-section of 1 cm and a thermometer. The silicone rubber wire is attached to the lower part of the adsorption bed 9 parallel to it.

[0048] The adsorption bed 9 is drawer-shaped and made of stainless steel. It is fixed by a snap-fit ​​on the inner wall of the main pipe 5 and is detachable. The adsorption bed 9 is filled with 200g of adsorbent 8 (columnar CHA zeolite molecular sieve or spherical 13X zeolite molecular sieve). The adsorbent 8 is used to adsorb CO2 in the dried gas and release it into the facility cultivation environment (the adsorption bed 9 is removed and the adsorbent 8 is replaced after every 5 to 7 adsorption-desorption cycles). The adsorbent 8 is covered with a layer of non-woven dustproof film 7.

[0049] The fixing component 11 is used to fix the main pipe 5 near the crop canopy, and can be a bracket or a hanging rope;

[0050] The power supply component 4 is used to power the device and is made of solar panels, which are fixed to the outside of the facility cultivation environment.

[0051] The method for using this device to capture carbon dioxide to improve crop photosynthetic efficiency and quality specifically includes the following steps:

[0052] (1) Place the main pipe in the device near the canopy of the facility horticulture crop, close the opening cover of the main pipe, close the heating component, turn on the exhaust device, and the gas is introduced into the main pipe through the drying pipe. The adsorbent captures CO2 until saturation, and the CO2 adsorption process is completed.

[0053] (2) Open the opening cover of the main pipeline, turn on the heating component, turn off the exhaust device, and release the CO2 captured by the adsorbent into the facility cultivation environment.

[0054] like Figure 2 As shown in Figure A, after the adsorbent has fully adsorbed CO2, the opening cap at the top of the main pipe 5 opens, the exhaust device 3 closes, and the heating element 10 turns on, releasing CO2 into the cultivation environment. The operation time is 1 hour. Figure 2 As shown in B, after the adsorbent has fully released CO2, the opening cover at the top of the main pipe 5 is closed, the heating component 10 is turned off, and the exhaust device 3 is turned on. The outside air of the greenhouse is introduced into the main pipe 5 through the drying pipe 6, and the CO2 in the air is captured by the adsorbent. The running time is 2-4 hours. The CO2 adsorption process is completed at night or during the photosynthetic midday break. The gas after CO2 adsorption is directly discharged into the facility cultivation environment through the exhaust pipe 2.

[0055] Example 2: CO2 Release Effect Test

[0056] The device was run multiple times according to the procedure in Example 1, and the CO2 release effect was detected by a CO2 recorder. The adsorbents were CHA zeolite molecular sieve and 13X zeolite molecular sieve, with quartz sand as the control material. The adsorbent dosage was 30 g / m³. 3 The desorption temperature was controlled between 80 and 120℃. To prevent interference from the plant's CO2 absorption rate on the detection results, this test was conducted in an environment without plants. The results are as follows: Figure 3 As shown, in the first five reuses, both types of molecular sieves were able to increase the CO2 concentration to 700-1700 μmol / mol. -1 The concentration reached the growth requirements of protected horticultural crops, but the effect of 13X zeolite molecular sieve gradually decreased, while the effect of CHA zeolite molecular sieve was more stable and had excellent reusability.

[0057] Example 3: Effects of long-term operation of the device on chlorophyll content in tomato leaves

[0058] Starting from 2 months of tomato age, the device was operated in a protected cultivation environment according to the method described in Example 1. Adsorption was initiated at 7:00 AM and 12:00 PM daily, and desorption began at 9:00 AM and 2:00 PM. The adsorbent and desiccant were replaced every 4 days. The tomato variety was 'Ailsa', with a plant spacing of 20 cm (the device is 0.5 m long and can cover three plants). The control group consisted of three untreated tomato plants in the same row, 2 m apart from the device. The adsorbent used in this example was CHA zeolite molecular sieve. After two weeks of operation, the chlorophyll content and net photosynthetic rate of the first functional leaf from top to bottom of the tomato plants were measured. The results are as follows: Figure 4 As shown, by Figure 4 As can be seen from A and B, after long-term operation of the device, the chlorophyll content of tomato leaves increased by 58%, the net photosynthetic rate increased by 66%, and the vegetative growth of tomatoes was significantly improved.

[0059] Example 4: The effect of long-term operation of the device on tomato fruit quality indicators

[0060] Starting from two months of tomato age, the device was operated in a protected cultivation environment according to the method described in Example 1. Adsorption was initiated at 7:00 AM and 12:00 PM daily, and desorption began at 9:00 AM and 2:00 PM. The adsorbent and desiccant were replaced every four days. The tomato variety was 'Ailsa', with a plant spacing of 20 cm (the device is 0.5 m long and can cover three plants). The control group consisted of three untreated tomato plants in the same row, 2 m apart from the device. The adsorbent used in this example was CHA zeolite molecular sieve. Two months after application, samples were taken from fully ripe, red fruits of the first cluster of fruit to test the soluble sugar and carotenoid content. The results are as follows: Figure 5 As shown. By Figure 5 As shown in A and B, after running the device, the main components of soluble sugars in tomatoes, glucose and fructose, increased by 35% and 91% respectively, the main carotenoids, lycopene, increased by 41%, lutein increased by 28%, and β-carotene increased by 35%, resulting in a significant improvement in the quality of tomato fruits.

[0061] The above embodiments provide a detailed description of the technical solution of the present invention. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for capturing carbon dioxide to improve crop photosynthetic efficiency and quality, characterized in that, An apparatus for improving crop photosynthetic efficiency and quality by capturing carbon dioxide, the apparatus comprising: an air extraction device (3), a drying tube (6), a main pipe (5), a fixing component (11), a power supply component (4), an air inlet pipe (1), and an air outlet pipe (2). The air extraction device (3) is used to drive the air outside the facility cultivation environment into the drying tube (6) through the air intake pipe (1). The drying tube (6) is used to dry the intake air and transport the dried gas to the main pipe (5). The drying tube (6) contains 3A molecular sieve or color-changing silica gel. The main pipe (5) is located inside the facility cultivation environment. It has an opening at the top and an opening cover that can be slidably installed to the opening by external force. The bottom is provided with a heating element (10), an adsorption bed (9) and an adsorbent (8) from bottom to top. The heating element (10) is used to heat the adsorbent (8) on the adsorption bed (9) to release the adsorbed CO2; the adsorption bed (9) is fixed on the inner wall of the main pipe (5); the adsorbent (8) is used to adsorb CO2 in the dried gas and release it into the facility cultivation environment, and CHA zeolite molecular sieve is selected. The fixing component (11) is used to fix the main pipe (5); The power supply component (4) is used to supply power to the device; The method for capturing carbon dioxide to improve crop photosynthetic efficiency and quality specifically includes the following steps: S01 Place the main pipe (5) in the device near the canopy of the facility horticulture crop, close the opening cover of the main pipe (5), close the heating component (10), open the exhaust device (3), so that the atmosphere outside the facility cultivation environment enters the drying pipe (6) through the air inlet pipe (1), and is introduced into the main pipe (5) through the drying pipe (6). The adsorbent (8) captures CO2 until saturation, and completes the CO2 adsorption process. The gas after CO2 adsorption is directly discharged into the facility cultivation environment through the air outlet pipe (2). S02 Open the opening cover of the main pipe (5), open the heating component (10), close the exhaust device (3), and release the CO2 captured by the adsorbent (8) into the facility cultivation environment; The protected horticultural crop is tomato, and the dosage of adsorbent is selected as 50-100 g / m³. 3 After the CHA zeolite molecular sieve captures CO2 for 2-4 hours to complete the CO2 adsorption process, it is then desorbed at 80-120 °C for more than 1 hour. Improving crop quality involves increasing the content of soluble sugars and carotenoids in crop fruits; After the adsorbent (8) has been reused 4-7 times, it needs to be regenerated by high-temperature drying before it can be used again. The high-temperature drying and regeneration conditions are 100-300 ℃ for 1-48 h. The CO2 adsorption process is carried out using the device at night or during the midday photosynthetic break, and the CO2 adsorption process is completed during the aforementioned time periods.

2. The method according to claim 1, characterized in that, In the device, the main pipe (5) also includes a dustproof membrane (7) covering the adsorbent (8); the inner wall of the main pipe (5) is also provided with a bayonet that cooperates with and fixes the adsorption bed (9) for fixing the adsorption bed (9).

3. The method according to claim 1, characterized in that, In the device, the power supply component (4) is a solar panel.

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