Greenhouse gas fertilizer and heat energy supply method based on biogas combustion

Abstract

The invention discloses a greenhouse gas fertilizer and heat energy supply method based on biogas combustion, and relates to the technical field of resource recycling, and the method comprises the following specific steps: pre-treating waste, sealing into a tank, and blending according to a preset carbon nitrogen ratio; performing segmented temperature control aeration fermentation, and performing dynamic regulation and control by utilizing a sensor and a proportional integral differential algorithm; fermentation waste heat is recycled, and biogas combustion is combined to assist heat supply; methane burns to generate carbon dioxide gas fertilizer, and residual water is supplied according to seasons after being treated; organic fertilizer returning is completed through fermentation, parameters are optimized through a time sequence weighted multi-factor fusion optimization algorithm, and system closed-loop management is achieved; according to the method, agricultural waste recycling is achieved through a combined process, a waste-energy-fertilizer-water resource closed-loop system is formed, the resource utilization rate is increased, and environmental dependence is reduced; meanwhile, the sensor and algorithm dynamic regulation and control are combined, the environment regulation and control accuracy is improved, and the biogas use safety is guaranteed through three-level safety protection and remote monitoring.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, specifically to a method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion. Background Technology

[0002] In current greenhouse cultivation, crops require a stable supply of heat and an appropriate concentration of carbon dioxide to ensure environmental requirements throughout their growth cycle. Agricultural production generates large amounts of solid waste annually, such as straw and livestock manure. Indiscriminate accumulation of this waste can lead to environmental burdens, and simple composting and incineration are insufficient to fully realize its organic value. Meanwhile, agricultural solid waste can be anaerobically fermented to produce biogas. The combustion of biogas releases heat and generates carbon dioxide, providing a technological foundation for bridging waste treatment and greenhouse needs. Currently, the industry has a real need for technologies that integrate waste resource utilization, biogas product utilization, and greenhouse environmental control.

[0003] In traditional related technologies, agricultural solid waste treatment and biogas utilization are often separate processes. Waste treatment is not deeply integrated with biogas production, and byproducts such as carbon dioxide and residual water after biogas combustion are often directly emitted without being adapted to the needs of greenhouse cultivation, resulting in an ineffective resource cycle. The adjustment of parameters in the greenhouse environment and fermentation process relies heavily on manual experience, lacking the means to collect multi-dimensional parameters in real time through sensors and dynamically control them using algorithms, making it difficult to match the needs of different growth stages of crops. In addition, safety protection measures during biogas use are relatively simple and lack a complete protection process, failing to fully guarantee the safety of the operation process. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion. This method involves adjusting agricultural waste to a preset carbon-nitrogen ratio of 25:1, and then producing biogas and bio-organic fertilizer through segmented temperature-controlled aeration fermentation. The waste heat from fermentation and biogas combustion are used for auxiliary heating. The carbon dioxide produced by biogas combustion is dynamically supplied as gas fertilizer. The waste water is treated and used for greenhouse irrigation seasonally. By combining sensors and proportional-integral-differential algorithms for precise control, and using a time-series weighted multi-factor algorithm to optimize parameters, the method achieves closed-loop resource utilization and intelligent management of the greenhouse environment, thereby improving resource utilization, reducing environmental dependence, and ensuring the safety of biogas use.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion, the specific steps of which are as follows: S1, Waste pretreatment and sealing into tank: Select agricultural solid waste and remove impurities. Mix high-nitrogen and high-carbon raw materials according to the preset carbon-nitrogen ratio. After crushing straw raw materials, mix them with other raw materials, adjust the moisture content of the mixture, and send them into the fermentation tank through the feeding device and seal it. S2, segmented temperature control and aeration and dynamic regulation of fermentation: Fermentation environmental parameters are collected by sensors installed in the fermentation tank and crop growth status and environmental parameters are collected by sensors installed in the greenhouse. The temperature and aeration status of the fermentation tank are controlled in segments according to the start-up period, main fermentation period, high-temperature decomposition period and aging stabilization period. The proportional-integral-differential algorithm is used to adjust the fermentation parameters based on the above collected parameters. S3, Fermentation waste heat recovery and dynamic heating: The heat generated during fermentation is recovered through the heat medium pipe in the fermentation tank, and after heat exchange, it is transported to the greenhouse heating device. Combined with the greenhouse temperature detection data, the biogas burner is started to assist in heating, and biogas use protection is implemented through preset safety protection operations. S4, Biogas Combustion for Fertilizer Production and Waste Water Utilization: Collect biogas produced by fermentation, dehydrate and desulfurize it before combustion, and send the carbon dioxide produced by combustion into the greenhouse through a gas fertilizer release device. Adjust the supply parameters according to the carbon dioxide concentration requirements of crops at different growth stages. The waste water produced by combustion is collected, treated and then transported to the greenhouse according to seasonal needs. S5, Organic Fertilizer Return to Field and System Closed-Loop Optimization: After fermentation, the bio-organic fertilizer in the fermentation tank is discharged and returned to the field. The system's entire operation data is stored. After each round of fermentation, the parameter combination is optimized using a time-series weighted multi-factor fusion optimization algorithm. The system operation is monitored and anomaly warnings are implemented through remote monitoring.

[0006] Furthermore, in step S1, the preset carbon-nitrogen ratio is 25:1, the mixing error is ≤±1, the high-nitrogen raw material is a mixture of dairy cow manure and pig manure in a mass ratio of 1:1, and the high-carbon raw material is a mixture of corn stalks and wheat stalks in a mass ratio of 2:1; the moisture content of the mixture is adjusted to 60%±2%.

[0007] Furthermore, in step S2, the temperature during the start-up period is controlled at 25℃±1℃, and the aeration frequency is once every 2 days for 30 minutes each time; the temperature during the main fermentation period is controlled at 55℃±2℃, and the aeration frequency is once a day for 40 minutes each time; the temperature during the high-temperature composting period is controlled at 75℃±2℃, maintained for 12 days, and aeration is stopped; the temperature during the aging and stabilization period is controlled at 50℃±1℃, and the cooling rate is 0.5℃ / day.

[0008] Furthermore, in step S2, the calculation formula for the proportional-integral-differential algorithm is as follows: ,in, The output value for fermentation parameter control refers to the adjustment amount of fermentation temperature, aeration frequency, or heat medium circulation flow rate. This is a proportionality coefficient, ranging from 0.1 to 1.0, used to adjust the sensitivity of the control response; This refers to the deviation between greenhouse demand and actual supply, specifically the difference between the target greenhouse temperature and humidity, carbon dioxide concentration, and real-time monitoring values. The integral time constant, with a value ranging from 10 to 60 s, is used to eliminate the steady-state error of the system. The differential time constant, with a value ranging from 1 to 10 s, is used to predict the trend of deviation changes and make early adjustments. To regulate time, that is, the duration for which the algorithm continues to run; This is the integral term of the deviation value over time, used to accumulate historical deviations and make corrections. This is the differential term of the deviation value with respect to time, used to reflect the rate of change of the deviation.

[0009] Furthermore, in step S2, fermentation environmental parameters are collected by temperature sensors and dissolved oxygen sensors arranged in layers along the height of the fermentation tank; crop growth status and environmental parameters are collected by air temperature and humidity sensors, carbon dioxide concentration sensors, leaf area index sensors, and soil temperature and humidity sensors evenly distributed in different areas of the greenhouse.

[0010] Furthermore, in step S3, the preset safety protection operations include biogas leak detection, automatic shut-off, and forced ventilation. The response concentration for biogas leak detection is 0.08% VOL. Automatic shut-off is initiated within 3 seconds of leak detection, and simultaneously, an airflow of ≥5000 m³ / h is activated. 3 Forced ventilation operation at / h, with softened water of total hardness ≤0.03mmol / L introduced into the heat medium pipe.

[0011] Furthermore, in step S4, the carbon dioxide concentration threshold is 800-1000 ppm during the seedling stage and 1200-1500 ppm during the flowering and fruiting stage, which is achieved by adjusting the biogas combustion rate by 5-50 mg / L. 3 The desulfurization efficiency of the dehydration and desulfurization treatment is ≥95% at a stable concentration of / h.

[0012] Furthermore, in step S4, the crop growth stage is determined by a combination of leaf area index and growth period days. The leaf area index is <0.5 for seedling stage and ≥2.0 for flowering and fruiting stage. The growth period days are 1-30 days for seedling stage and 31-90 days for flowering and fruiting stage. The response time for adjusting the supply parameters is ≤10s.

[0013] Furthermore, in step S4, the remaining water is filtered with a precision of 20μm-100μm and then transported through the roof spray pipes during winter and spring, while in other seasons it is connected to the greenhouse drip irrigation system.

[0014] Furthermore, in step S5, the calculation formula for the time-weighted multi-factor fusion optimization algorithm is as follows: ,in, This is the optimized combination of core fermentation parameters; The number of factor types, with a value of 3; The time-series weighting coefficients satisfy the following conditions: =1, with a value range of 0.2-0.5; The weights for factor importance are: fermentation factor 0.4, environmental factor 0.3, and crop factor 0.3. Let be the parameter fitting function for the k-th factor; For the input data set of the k-th factor; This is a stage correction factor with a value range of 0.9-1.1. It is a parameter constraint term with a value of 1.

[0015] Compared with existing technologies, this greenhouse gas fertilizer and heat energy supply method based on biogas combustion has the following advantages: I. This invention utilizes a combined process of pre-setting the carbon-nitrogen ratio of agricultural solid waste, segmented temperature-controlled aeration fermentation, and tiered utilization of biogas combustion products to transform agricultural solid waste such as straw and livestock manure into two core products: biogas and bio-organic fertilizer. Simultaneously, it makes targeted use of carbon dioxide, waste heat, and waste water generated during biogas combustion. Specifically, carbon dioxide is dynamically supplied according to the concentration requirements of crops at different growth stages as a form of gas fertilizer; fermentation waste heat and biogas combustion auxiliary heating work together to ensure stable greenhouse temperature; and waste water, after graded filtration, is adapted to winter and spring spraying and drip irrigation needs in other seasons. This forms a closed-loop utilization system of "waste-energy-fertilizer-water resources," completely solving the environmental pollution and resource waste problems caused by the indiscriminate disposal of traditional agricultural solid waste, significantly improving the comprehensive utilization rate of agricultural resources, and reducing the dependence of greenhouse cultivation on external energy and water resources.

[0016] Second, this invention uses a sensor array to collect real-time parameters of the fermentation environment, greenhouse environment, and crop growth status. It dynamically adjusts fermentation parameters using a proportional-integral-differential algorithm, and employs a time-weighted multi-factor fusion optimization algorithm to achieve autonomous iterative optimization of fermentation parameters for each round. Simultaneously, it uses leaf area index and growth period days as dual indicators to jointly determine the crop growth stage, effectively avoiding the limitations of traditional greenhouse control that relies on manual experience and has poor parameter adaptability. This significantly improves the accuracy and response efficiency of fermentation and greenhouse environment control. Furthermore, through a three-level safety protection system of biogas leak detection, automatic shut-off, and forced ventilation, combined with system operation data storage and remote monitoring, it comprehensively ensures the safety of biogas use, achieving traceability and anomaly early warning throughout the entire greenhouse planting process, providing stable and reliable technical support for large-scale, refined greenhouse planting.

[0017] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1 This is a flowchart of a greenhouse gas fertilizer and heat energy supply method based on biogas combustion; Figure 2 This is a framework diagram of a greenhouse gas fertilizer and heat energy supply method based on biogas combustion. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] Example 1: like Figure 1 As shown, the greenhouse gas fertilizer and heat energy supply method based on biogas combustion provided in the first embodiment of the present invention specifically includes steps S1 to S5, and the implementation steps are as follows: S1. Waste Pretreatment and Sealing into Tank: Corn stalks, wheat stalks, dairy cow manure, and pig manure are selected as raw materials. Impurities such as stones and plastic fragments mixed in the raw materials are first removed. High-nitrogen and high-carbon raw materials are mixed at a carbon-to-nitrogen ratio of 25:1. The high-nitrogen raw material is a 1:1 mass mixture of dairy cow manure and pig manure, and the high-carbon raw material is a 2:1 mass mixture of corn stalks and wheat stalks. The straw raw materials are crushed to a particle size of less than 4cm using a hammer mill and then added to a horizontal mixer along with the high-nitrogen raw materials and thoroughly mixed until homogeneous. Water is then evenly sprayed onto the materials, and the moisture content is monitored in real time using a moisture meter. The moisture content of the mixture is adjusted to 59%, with a mixing error controlled within ±0.7. The mixture is then conveyed to a cylindrical fermentation tank with a diameter of 3m and a height of 5m using a screw feeder. After filling the tank to 80% capacity, the top sealing cap is closed, and the sealing performance is checked to ensure no leakage.

[0022] S2, segmented temperature-controlled aeration and dynamic fermentation regulation: Three sets of platinum resistance temperature sensors are installed along the height direction of the fermentation tank at distances of 1m, 2.5m, and 4m from the bottom of the tank; one set of dissolved oxygen sensors is installed in the middle and lower parts of the tank. In a 500㎡ greenhouse, air temperature and humidity sensors and carbon dioxide concentration sensors are evenly distributed at a density of one set per 50㎡; leaf area index sensors are installed in the middle of the crop planting rows; and soil temperature and humidity sensors are installed at a depth of 20cm in the root distribution layer. The fermentation process is controlled in four stages: Start-up phase: The temperature is controlled at 24℃ by the tank heating device, and the Roots blower is used to aerate once every 2 days for 30 minutes each time, with an aeration pressure of 0.02MPa; Main fermentation period: Raise the temperature to 53℃, aerate once a day for 40 minutes each time, and adjust the aeration pressure to 0.03MPa; High-temperature composting period: Maintain the temperature at 74℃ for 12 days, during which aeration is stopped; Aging stabilization period: Cool down to 49℃ at a rate of 0.5℃ / day.

[0023] Fermentation environmental parameters, greenhouse environment parameters, and crop growth parameters are collected every 10 minutes using sensors. A proportional-integral-differential (PID) algorithm is used to dynamically adjust fermentation parameters such as heating power and aeration time based on the collected data. The calculation formula for the PID algorithm is as follows: ,in, Output values ​​for adjusting fermentation parameters; This is a proportionality coefficient used to adjust the sensitivity of the control response; This represents the deviation between greenhouse demand and actual supply. The integral time constant; The differential time constant; To regulate time; This is the integral term of the deviation value over time; This is the differential term of the deviation value with respect to time.

[0024] S3 fermentation waste heat recovery and dynamic heating A 50mm diameter spiral stainless steel heat transfer pipe is welded to the inner wall of the fermentation tank. Softened water with a total hardness of 0.02 mmol / L flows through the heat transfer pipe, and a circulating pump drives the flow of the softened water to recover waste heat generated during fermentation. After heat exchange with tap water via a shell-and-tube heat exchanger, the waste heat is delivered as 45°C hot water to the greenhouse radiator heating system, which is arranged around the greenhouse perimeter and the central aisle. Temperature is monitored in real time by greenhouse air temperature and humidity sensors. When the temperature drops below 19°C, a 50kW biogas burner automatically activates for auxiliary heating. Safety precautions are implemented during biogas use: a combustible gas detector is installed at the biogas pipeline valve. When a biogas leak concentration reaches 0.08% VOL, the electric shut-off valve of the gas pipeline is triggered to close within 3 seconds, and simultaneously, a 5200m³ / h airflow is activated. 3 Forced ventilation is provided by an axial flow fan with a capacity of / h.

[0025] S4, Biogas Combustion for Fertilizer Production and Waste Water Utilization: Biogas produced during fermentation is collected through the biogas outlet at the top of the tank. It is first dehydrated using a refrigerated dryer to control the dew point temperature to ≤5℃, and then desulfurized using an activated carbon desulfurization tower. The desulfurization efficiency was measured at 97%. The treated biogas is then fed into the burner. Crop growth stage is determined using sensor data: when the crop leaf area index is <0.5 and the growing season is 5-28 days, the greenhouse carbon dioxide concentration is controlled at 850ppm, and the biogas combustion rate is adjusted to 18m³ / h. 3 / h; When the leaf area index is ≥2.0 and the growing season is 35-88 days, the carbon dioxide concentration is controlled at 1250ppm, and the biogas combustion rate is adjusted to 32m³ / h. 3 / h. The residual water produced by combustion has a temperature of 30-35℃. After being treated by a bag filter with a precision of 30μm, it is transported through a rotating sprinkler head pipeline installed on the roof of the greenhouse during the winter and spring seasons and sprayed evenly onto the crop leaves and the ground surface. In other seasons, it is connected to the greenhouse drip irrigation system and precisely irrigated to the crop root zone through drippers.

[0026] S5, Organic Fertilizer Return to Field and System Closed-Loop Optimization: After fermentation, when the gas production rate of the tank drops to 0.1m³... 3 / (m 3 •d) When the following steps are performed, open the discharge valve at the bottom of the tank to discharge the bio-organic fertilizer via a screw conveyor. It is then transported to the greenhouse planting area via a belt conveyor, where it is evenly spread using a fertilizer spreader. Finally, a rotary tiller turns the organic fertilizer into the soil to a depth of 20cm for return to the field. The system stores all operational data via an industrial controller, including temperature, aeration parameters, and biogas usage at each stage. After each fermentation cycle, a time-weighted multi-factor fusion optimization algorithm is used to optimize the parameter combination. The calculation formula for the time-weighted multi-factor fusion optimization algorithm is as follows: ,in, This is the optimized combination of core fermentation parameters; Number of factor types; The time-series weighting coefficients satisfy the following conditions: =1; For factor importance weights; Let be the parameter fitting function for the k-th factor; For the input data set of the k-th factor; This is a stage correction factor; These are parameter constraints; the time-series weighting coefficients are allocated at 0.2, 0.4, and 0.4, respectively; the fermentation factor weight is 0.4, the environmental factor weight is 0.3, and the crop factor weight is 0.3; the stage correction coefficient is fixed at 1.0. The operating data is uploaded to a remote monitoring platform via Ethernet, displaying the system status in real time. When parameters exceed the set range, the platform automatically sends SMS alerts to administrators.

[0027] like Figure 2As shown, in this embodiment, each step forms a complete closed-loop connection: the pretreated mixture in S1 enters S2 for fermentation, producing three core products: fermentation waste heat, biogas, and organic fertilizer; the fermentation waste heat is converted into the heat energy required by the greenhouse through the heat exchange and auxiliary heating system in S3; the biogas is burned after dehydration and desulfurization treatment in S4 to generate carbon dioxide fertilizer suitable for crop needs and filtered waste water; and the organic fertilizer is directly returned to the field for reuse in S5; at the same time, the system's full-process operation data is used for parameter iteration of the time-series weighted multi-factor fusion optimization algorithm, which in turn guides the operation of each step, realizing the circular flow of "waste-energy-fertilizer-water resources".

[0028] In summary, this embodiment utilizes corn stalks, wheat stalks, dairy cow manure, and pig manure as raw materials, blended at a carbon-to-nitrogen ratio of 25:1 and with a controlled moisture content of 59%. Through segmented temperature-controlled fermentation, waste heat recovery for heating, and biogas desulfurization and dehydration treatment, carbon dioxide is dynamically supplied to crops during the seedling and flowering / fruiting stages. Residual water is filtered through a 30μm filter and used for seasonal irrigation. Finally, organic fertilizer is returned to the field, and parameters are optimized using algorithms. Throughout the entire process, sensors collect data in real time, and safety protection operations are implemented simultaneously, fully covering the entire process from waste pretreatment to system optimization. This verifies the feasibility and stability of this method in small-to-medium-sized greenhouses.

[0029] Example 2: like Figure 1 As shown, the greenhouse gas fertilizer and heat energy supply method based on biogas combustion provided in the first embodiment of the present invention specifically includes steps S1 to S5, and the implementation steps are as follows: S1. Waste Pretreatment and Sealing into Tank: Corn stalks, wheat stalks, dairy cow manure, and pig manure are selected as raw materials. After removing impurities, the raw materials are mixed at a carbon-to-nitrogen ratio of 25:1. The high-nitrogen raw material is a 1:1 mass mixture of dairy cow manure and pig manure, precisely measured using an electronic scale, with a mixing error controlled within ≤0.5%. The high-carbon raw material is a 2:1 mass mixture of corn stalks and wheat stalks. The straw raw materials are pulverized to a particle size of less than 6cm using a shear crusher and then added to a vertical mixer along with the high-nitrogen raw materials. The mixture is stirred for 15 minutes until homogeneous. Groundwater is sprayed into the mixture, and a portable moisture meter is used to measure and adjust the moisture content to 61%, with a mixing error controlled within ±0.9%. The mixture is conveyed via a belt conveyor at a speed of 0.5m / s into a vertical fermentation tank with a diameter of 4m and a height of 6m. After the tank is filled to 75% capacity, the sealing cover is closed and the sealing ring is checked for tightness.

[0030] S2, segmented temperature-controlled aeration and dynamic fermentation regulation: Four sets of thermocouple temperature sensors are installed at heights of 1.5m, 3m, 4.5m, and 5.5m from the bottom of the fermentation tank. One set of dissolved oxygen sensors is installed at the top, middle, and bottom of the tank. In an 800㎡ greenhouse, air temperature and humidity sensors and carbon dioxide concentration sensors are evenly distributed at a density of one set per 60㎡. Leaf area index sensors are distributed in a "quincunx" pattern in the crop planting area. Soil temperature and humidity sensors are installed at one point per 100㎡ in different plots. Fermentation stage control parameters: Start-up phase: Maintain the temperature at 26℃, and use a centrifugal fan to aerate once every 2 days, each time for 30 minutes, with an aeration flow rate of 50 m³ / h. 3 / h; Main fermentation period: Raise the temperature to 57℃, aerate once a day for 40 minutes each time, and adjust the aeration flow rate to 60 m³ / h. 3 / h; High-temperature composting period: Maintain the temperature at 76℃ for 12 days, during which aeration is stopped; Aging stabilization period: Cool down to 51℃ at a rate of 0.5℃ / day.

[0031] The sensor collects data every 15 minutes, and the proportional-integral-differential algorithm is used to adjust parameters such as the power of the tank heating rod and the aeration flow rate of the blower based on the collected data to ensure a stable fermentation environment.

[0032] S3, Fermentation Waste Heat Recovery and Dynamic Heating: A 40mm diameter serpentine seamless steel heat transfer pipe is laid in the inner and outer layers of the fermentation tank. Softened water treated by an ion exchanger (total hardness 0.03 mmol / L) flows through the pipe, and a hot water circulation pump drives the flow of this softened water to recover fermentation waste heat. After heat exchange in a plate heat exchanger, the waste heat is delivered as 50°C hot water to the greenhouse underfloor heating system, which is installed under the walkways in the planting area. When the greenhouse temperature drops below 21°C, an 80kW biogas burner is activated for auxiliary heating. Biogas safety protection operation: A combustible gas detector monitors the leak concentration in real time. When the concentration reaches 0.08% VOL, the main gas valve is shut off within 3 seconds, and a 5500m³ / h airflow is activated simultaneously. 3 A centrifugal fan with a capacity of / h ensures that the biogas concentration inside the greenhouse is rapidly reduced to a safe level of <0.05%VOL.

[0033] S4, Biogas Combustion for Fertilizer Production and Waste Water Utilization: The biogas produced during fermentation undergoes preliminary impurity removal via a cyclone separator, followed by dehydration in an adsorption dryer to control the moisture content to ≤0.1%. It then passes through a zinc oxide desulfurizing agent for further desulfurization, achieving a desulfurization efficiency of 96%. The treated biogas is then fed into the burner. Crop growth stages are determined using sensor data: when the crop leaf area index is <0.5 and the growing season is 8-30 days, the greenhouse carbon dioxide concentration is controlled at 950 ppm, and the biogas combustion rate is adjusted to 22 m³ / h. 3 / h; When the leaf area index is ≥2.0 and the growing season is 32-90 days, the carbon dioxide concentration is controlled at 1450ppm, and the biogas combustion rate is adjusted to 38m³ / h. 3 / h. The residual water produced by combustion is treated by a cartridge filter with a precision of 70μm and then transported through a fixed sprinkler system installed on the roof during the winter and spring seasons. The sprinkler system has a spray radius of 2m and sprays at different times, such as 9 am and 3 pm. During other seasons, it is connected to the greenhouse drip irrigation branch pipe, and the drip irrigation flow is controlled by a pressure regulating valve to achieve precise irrigation.

[0034] S5, Organic Fertilizer Return to Field and System Closed-Loop Optimization: After fermentation, the bio-organic fertilizer is discharged through the side outlet of the tank. Unfermented impurities are removed by a vibrating screen with a 1cm aperture. The fertilizer is then transported to the greenhouse by a dump truck and applied into the crop planting furrows using a ditching fertilizer applicator. The furrows are 15cm deep, and then covered with soil to complete the return to the field. The system stores the entire operation data through a data acquisition module. After each round of fermentation, a time-weighted multi-factor fusion optimization algorithm is used to optimize the parameter combination. The time-series weight coefficients are allocated as 0.3, 0.4, and 0.3, with fermentation factor weighting at 0.4, environmental factor weighting at 0.3, and crop factor weighting at 0.3. The stage correction coefficient is 0.9 for the seedling stage and 1.1 for the flowering and fruiting stage. The operation data is uploaded to a remote monitoring APP via a 4G module, allowing managers to view the data in real time. When the system triggers an anomaly, the APP pushes an alarm message and displays the location of the anomaly.

[0035] like Figure 2 As shown, the closed-loop system in this embodiment is further adapted to the needs of large-area greenhouses: after the mixture of materials in S1 is fermented in S2, fermentation waste heat, biogas and organic fertilizer are output simultaneously; the fermentation waste heat is efficiently supplied to the greenhouse through the underfloor heating system in S3; the biogas is treated in S4 to generate high-concentration carbon dioxide fertilizer and waste water that can be used in different time periods / systems; the organic fertilizer is precisely reused after being cleaned, dredged and returned to the field in S5; the system operation data is remotely transmitted and optimized by algorithms to form a closed-loop management of "raw material input - multi-product output - product reuse - parameter optimization" to ensure maximum utilization of resources.

[0036] In summary, in this embodiment, the raw materials remain corn stalks, wheat stalks, dairy cow manure, and pig manure. During mixing, the moisture content is controlled at 61%, and the stalk particle size is 6cm. During the fermentation stage, more sensors are used for monitoring, aeration flow is adjusted, and underfloor heating is employed. After biogas treatment, carbon dioxide is supplied to the crops. Residual water is filtered through a 70μm filter and then sprayed or drip-irrigated in stages. Organic fertilizer is removed and returned to the field through ditching. The algorithm optimization involves differentiated setting of stage correction coefficients, and the implementation process is adapted to larger greenhouse areas. This demonstrates that the technical solution can be adjusted according to the greenhouse size and actual needs, possessing broad application potential.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion, characterized in that, The specific steps of this method are as follows: S1, Waste pretreatment and sealing into tank: Select agricultural solid waste and remove impurities. Mix high-nitrogen and high-carbon raw materials according to the preset carbon-nitrogen ratio. After crushing straw raw materials, mix them with other raw materials, adjust the moisture content of the mixture, and send them into the fermentation tank through the feeding device and seal it. S2, segmented temperature control and aeration and dynamic regulation of fermentation: Fermentation environmental parameters are collected by sensors installed in the fermentation tank and crop growth status and environmental parameters are collected by sensors installed in the greenhouse. The temperature and aeration status of the fermentation tank are controlled in segments according to the start-up period, main fermentation period, high-temperature decomposition period and aging stabilization period. The proportional-integral-differential algorithm is used to adjust the fermentation parameters based on the above collected parameters. S3, Fermentation waste heat recovery and dynamic heating: The heat generated during fermentation is recovered through the heat medium pipe in the fermentation tank, and after heat exchange, it is transported to the greenhouse heating device. Combined with the greenhouse temperature detection data, the biogas burner is started to assist in heating, and biogas use protection is implemented through preset safety protection operations. S4, Biogas Combustion for Fertilizer Production and Waste Water Utilization: Collect biogas produced by fermentation, dehydrate and desulfurize it before combustion, and send the carbon dioxide produced by combustion into the greenhouse through a gas fertilizer release device. Adjust the supply parameters according to the carbon dioxide concentration requirements of crops at different growth stages. The waste water produced by combustion is collected, treated and then transported to the greenhouse according to seasonal needs. S5, Organic Fertilizer Return to Field and System Closed-Loop Optimization: After fermentation, the bio-organic fertilizer in the fermentation tank is discharged and returned to the field. The system's entire operation data is stored. After each round of fermentation, the parameter combination is optimized using a time-series weighted multi-factor fusion optimization algorithm. The system operation is monitored and anomaly warnings are implemented through remote monitoring.

2. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S1, the preset carbon-nitrogen ratio is 25:1, the mixing error is ≤±1, the high-nitrogen raw material is a mixture of dairy cow manure and pig manure in a mass ratio of 1:1, and the high-carbon raw material is a mixture of corn stalks and wheat stalks in a mass ratio of 2:1; the moisture content of the mixture is adjusted to 60%±2%.

3. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S2, the temperature during the start-up period is controlled at 25℃±1℃, and the aeration frequency is once every 2 days for 30 minutes each time; the temperature during the main fermentation period is controlled at 55℃±2℃, and the aeration frequency is once a day for 40 minutes each time; the temperature during the high-temperature composting period is controlled at 75℃±2℃, maintained for 12 days, and then aeration is stopped; the temperature during the aging and stabilization period is controlled at 50℃±1℃, and the cooling rate is 0.5℃ / day.

4. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S2, the calculation formula for the proportional-integral-differential algorithm is as follows: ,in, Output values ​​for adjusting fermentation parameters; This is a proportionality coefficient used to adjust the sensitivity of the control response; This represents the deviation between greenhouse demand and actual supply. The integral time constant; The differential time constant; To adjust the time; This is the integral term of the deviation value over time; This is the differential term of the deviation value with respect to time.

5. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S2, fermentation environmental parameters are collected by temperature sensors and dissolved oxygen sensors arranged in layers along the height of the fermentation tank; crop growth status and environmental parameters are collected by air temperature and humidity sensors, carbon dioxide concentration sensors, leaf area index sensors, and soil temperature and humidity sensors evenly distributed in different areas of the greenhouse.

6. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S3, the preset safety protection operations include biogas leak detection, automatic shut-off, and forced ventilation. The response concentration for biogas leak detection is 0.08% VOL. Automatic shut-off is initiated within 3 seconds of leak detection, and simultaneously, an airflow of ≥5000 m³ / h is activated. 3 Forced ventilation operation at / h, with softened water of total hardness ≤0.03mmol / L introduced into the heat medium pipe.

7. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S4, the carbon dioxide concentration threshold is 800-1000 ppm during the seedling stage and 1200-1500 ppm during the flowering and fruiting stage, which is achieved by adjusting the biogas combustion rate by 5-50 mg / L. 3 The desulfurization efficiency of the dehydration and desulfurization treatment is ≥95% at a stable concentration of / h.

8. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S4, the crop growth stage is determined by a combination of leaf area index and growth period days. The leaf area index is <0.5 for seedling stage and ≥2.0 for flowering and fruiting stage. The growth period days are 1-30 days for seedling stage and 31-90 days for flowering and fruiting stage. The response time for adjusting the supply parameters is ≤10s.

9. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S4, the remaining water is filtered with a precision of 20μm-100μm and then transported through the roof spray pipes during winter and spring, and connected to the greenhouse drip irrigation system during other seasons.

10. The method for supplying greenhouse gas fertilizer and heat energy based on biogas combustion according to claim 1, characterized in that, In step S5, the calculation formula for the time-weighted multi-factor fusion optimization algorithm is as follows: ,in, This is the optimized combination of core fermentation parameters; Number of factor types; The time-series weighting coefficients satisfy the following conditions: =1; For factor importance weights; Let be the parameter fitting function for the k-th factor; Let be the input data set for the k-th type of factor; This is a stage correction factor; These are parameter constraint terms.

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