Comprehensive utilization method and equipment of biogas slurry combined with water and fertilizer integration

Abstract

The application discloses a comprehensive utilization method and equipment of biogas slurry and water and fertilizer integration, and the method comprises the following steps: pretreating and solid-liquid separating the biogas slurry to obtain biogas slurry clear liquid; performing cyclone sand removal, multi-stage filtration and stabilization treatment on the clear liquid to obtain purified and stabilized biogas slurry; performing real-time monitoring on nitrogen, phosphorus, potassium, EC and pH of the purified biogas slurry through an online detection device, calculating the amount of supplementary fertilizer according to a crop fertilizer requirement model; performing accurate proportioning in a dynamic mixing device to prepare a standardized fertilizer liquid; and finally injecting the fertilizer liquid into an irrigation pipe network in proportion through a water and fertilizer integration system to realize accurate fertilization. The application also provides a comprehensive utilization equipment matched with the method, which comprises a pretreatment unit, a deep purification unit, a detection and adjustment unit, a water and fertilizer integration unit and a buffer storage unit. The technology realizes harmless and stabilized utilization of the biogas slurry, improves the nutrient utilization rate, reduces the pollution risk, guarantees the safe operation of a drip irrigation system and has good agricultural and environmental comprehensive benefits.

Description

Technical Field

[0001] This invention relates to a comprehensive utilization method and equipment that combines biogas slurry with fertigation. Background Technology

[0002] With the development of large-scale livestock farming and biogas projects, the production of biogas slurry is constantly increasing. Biogas slurry is rich in nitrogen, phosphorus, potassium, and organic matter, making it an excellent source of liquid fertilizer. However, current methods of utilizing biogas slurry mainly involve direct application to the field or simple storage followed by application, which presents the following problems: 1. High levels of suspended solids and impurities Untreated biogas slurry contains a large amount of suspended solids and fine sand, which can easily clog drip irrigation, micro-sprinkler irrigation and other integrated water and fertilizer systems, limiting their direct application.

[0003] 2. Large fluctuations in composition The nutrient content of biogas slurry varies greatly depending on the fermentation raw materials, season, and operating conditions, making it difficult to accurately match with the fertilizer requirements of crops, which can easily lead to nutrient excess or deficiency.

[0004] 3. Poor stability Biogas slurry contains reducing substances, high levels of COD and BOD, and is prone to producing odors, decay, or adverse effects on crop roots.

[0005] 4. Lack of intelligent allocation Existing technologies mostly involve fixed-ratio mixing and lack online detection and dynamic adjustment mechanisms, making it difficult to achieve precise fertilization.

[0006] Therefore, there is an urgent need for a comprehensive utilization method and equipment that can combine biogas slurry treatment, stabilization, testing, fertilizer blending, and fertigation to achieve efficient, safe, and precise utilization of biogas slurry resources. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a comprehensive utilization method and equipment that combines biogas slurry with fertigation.

[0008] The comprehensive utilization method combining biogas slurry with fertigation includes the following steps: S1. Pretreatment and solid-liquid separation of biogas slurry: The raw biogas slurry from the biogas slurry pond is subjected to solid-liquid separation to obtain clear biogas slurry and biogas residue. The pretreatment includes removing large debris through a screen and adjusting the pH of the biogas slurry to 6.0-7.5. S2 Deep purification and stabilization of biogas slurry: The biogas slurry obtained in step S1 is sent to the deep purification unit, where fine sand and gravel are removed by a cyclone desanding device and suspended particulate matter is removed by a multi-layer filtration device with a filtration accuracy of not less than 120 mesh. Then it enters the stabilization reaction tank and is treated for a short time by aeration or the addition of stabilizers to reduce COD, BOD and possible reducing harmful substances in oxidation, so as to obtain purified and stabilized biogas slurry. S3 Online Nutrient Detection and Formula Adjustment: Real-time online detection of the main nutrients N, P, K, EC value, and pH value of the purified and stabilized biogas slurry obtained in step S2 is performed. Based on the fertilizer requirements of the target crop at the current growth stage, the types and amounts of fertilizers to be supplemented are calculated. S4 Precision Mixing and Fertilizer Solution Preparation: In the dynamic mixing device, the purified and stabilized biogas slurry is uniformly mixed with the fertilizer added according to the calculation results in step S3. During the mixing process, the EC and pH of the mixed fertilizer solution are monitored in real time and fine-tuned to prepare a standardized fertilizer solution that meets the requirements for irrigation and fertilization. S5 Precision application of integrated water and fertilizer: The standardized fertilizer solution prepared in step S4 is injected into the irrigation mother liquor tank of the integrated water and fertilizer system or directly injected into the main irrigation pipeline through the fertilizer injection pump in proportion. After being mixed with irrigation water in a preset ratio, it is delivered to the crop root area through field drip irrigation or micro-sprinkler irrigation network to achieve simultaneous and precise supply of water and fertilizer.

[0009] As a further improvement, the multi-layer filtration device in step S2 is a combination of a sand filter and a disc filter. The combination of sand filter and disc filter can achieve coarse filtration and fine filtration in tandem, improve filtration accuracy and reduce the risk of clogging.

[0010] As a further improvement, the stabilizer in step S2 is hydrogen peroxide or sodium hypochlorite. Using hydrogen peroxide or sodium hypochlorite as a stabilizer results in a rapid and easily controlled reaction, which can effectively reduce COD and kill harmful microorganisms.

[0011] A comprehensive utilization equipment for integrating biogas slurry and fertigation to implement the method includes a pretreatment unit, a deep purification and stabilization unit, a detection and blending unit, a fertigation integration unit, and a storage and buffering unit connected sequentially along the material flow direction. The pretreatment unit includes a bar screen well, a pH adjustment tank, and a solid-liquid separator; The deep purification and stabilization unit includes a cyclone sand separator, at least one sand and gravel filter, a first-stage disc filter, and a subsequent stabilization reaction tank, all connected in sequence. The detection and mixing unit includes an online detection device, a central control system, and a dynamic mixing device; The integrated water and fertilizer unit includes an irrigation water source, an irrigation pump, an irrigation main pipeline, a fertilizer injection pump, an irrigation mother liquor tank, and a drip irrigation tape or micro-sprinkler network deployed in the field; the outlet of the dynamic mixing device is connected to the irrigation main pipeline through the fertilizer injection pump, or directly connected to the irrigation mother liquor tank. The storage and buffering unit includes a biogas slurry clear liquid temporary storage tank set after solid-liquid separation and before deep purification, and a purified biogas slurry storage tank set after deep purification and before testing and blending, for buffering and ensuring continuous operation of the system.

[0012] As a further improvement, the solid-liquid separator is a screw extrusion separator, which has high separation efficiency, stable operation, and is suitable for continuous processing of biogas slurry with high solid content.

[0013] As a further improvement, the stabilization reaction tank is equipped with an aeration device or a dosing device. The stabilization reaction tank is equipped with an aeration or dosing device, and the treatment method can be flexibly selected according to different biogas slurry characteristics.

[0014] As a further improvement, the online detection device integrates at least an ammonia nitrogen / nitrate sensor, a potassium ion sensor, a pH sensor, and an EC sensor. The central control system is a PLC or computer with a built-in crop fertilizer requirement model and formulation algorithm. The dynamic mixing device is equipped with a stirrer and connected to a solid / liquid fertilizer replenishment silo and a metering addition device. By integrating multiple sensors and a PLC control system, it can achieve real-time detection, intelligent formula calculation, and automatic formulation, thereby improving the accuracy and automation level of fertilization.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Achieve stable and safe utilization of biogas slurry: Through solid-liquid separation, cyclone sand removal, multi-stage filtration and stabilization treatment, the suspended solids, COD and harmful reducing substances are significantly reduced, and the stability of biogas slurry is improved.

[0016] 2. Prevent drip irrigation system clogging: Multi-stage filtration and stabilization treatment ensure that the fertilizer solution meets the requirements of drip irrigation and micro-sprinkler systems, extending the service life of the irrigation system.

[0017] 3. Achieve precise fertilizer application: By online detection of N, P, K, EC and pH, and combined with crop fertilizer requirement models, fertilizer supplementation is dynamically calculated to achieve precise fertilization.

[0018] 4. Improve fertilizer utilization: Precise mixing of biogas slurry and chemical fertilizer improves nutrient utilization efficiency and reduces the amount of chemical fertilizer used.

[0019] 5. Reduce environmental pollution risks: Reduce water pollution and soil load caused by direct discharge of biogas slurry, and realize resource utilization.

[0020] 6. Continuous and stable system operation: Multi-level buffer and storage units are set up to ensure continuous system operation and improve adaptability.

[0021] 7. Enables automated and intelligent control: PLC or computer control system combined with online detection and adjustment algorithms to achieve automated operation and intelligent management. Attached Figure Description

[0022] Figure 1 It is a flowchart of a comprehensive utilization method that combines biogas slurry with water and fertilizer integration; Figure 2 This is a system block diagram of equipment for a comprehensive utilization method that integrates biogas slurry with water and fertilizer. Detailed Implementation

[0023] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0024] like Figure 1 As shown, a comprehensive utilization method combining biogas slurry and fertigation includes the following steps: S1 Pretreatment and solid-liquid separation of biogas slurry: solid-liquid separation is performed on the raw biogas slurry from the anaerobic digester to obtain clear biogas slurry and biogas residue; the pretreatment includes removing large debris through a screen and adjusting the pH of the biogas slurry to 6.0-7.5.

[0025] S2 Deep purification and stabilization of biogas slurry: The biogas slurry obtained in step S1 is sent to a deep purification unit, where it is passed through a cyclone desanding device to remove fine sand and gravel, and through a multi-layer filtration device, preferably a combination of "sand filter + disc filter" to remove suspended particulate matter, with a filtration accuracy of not less than 120 mesh; then it enters a stabilization reaction tank, where it is treated for a short time by aeration or by adding stabilizers such as hydrogen peroxide or sodium hypochlorite to reduce COD, BOD and any potentially harmful reducing substances that may be present in the oxidation process, thus obtaining purified and stabilized biogas slurry.

[0026] S3 Online Nutrient Detection and Formula Adjustment: Real-time online detection of the main nutrients N, P, K, EC value, and pH value of the purified and stabilized biogas slurry obtained in step S2; Based on the fertilizer requirements of the target crop at the current growth stage, the central control system calculates the types and amounts of fertilizers to be supplemented, such as urea, potassium dihydrogen phosphate, and potassium sulfate.

[0027] S4 Precision Mixing and Fertilizer Solution Preparation: In a dynamic mixing device, purified and stabilized biogas slurry is uniformly mixed with fertilizer added according to the calculation results in step S3. During the mixing process, the EC and pH of the mixed fertilizer solution are monitored in real time and fed back to the control system for fine-tuning, thus preparing a standardized fertilizer solution that meets the requirements for irrigation and fertilization.

[0028] S5 Precision application of integrated water and fertilizer: The standardized fertilizer solution prepared in step S4 is injected into the irrigation mother liquor tank of the integrated water and fertilizer system or directly injected into the main irrigation pipeline through the fertilizer injection pump in proportion. After being mixed with irrigation water in a preset ratio, it is delivered to the crop root area through field drip irrigation or micro-sprinkler irrigation network to achieve simultaneous and precise supply of water and fertilizer.

[0029] like Figure 2 As shown, this invention provides a comprehensive utilization equipment for integrating biogas slurry and water and fertilizer to achieve the above method, comprising the following components connected sequentially along the material flow direction: The pretreatment unit includes a bar screen well, a pH adjustment tank, and a solid-liquid separator, such as a screw extruder.

[0030] The deep purification and stabilization unit includes a cyclone sand separator, at least one primary sand and gravel filter, a primary disc filter, and a subsequent stabilization reaction tank, equipped with an aeration device or a dosing device.

[0031] The detection and blending unit includes an online detection device, which integrates at least an ammonia nitrogen / nitrate sensor, a potassium ion sensor, a pH sensor, and an EC sensor. The central control system includes a PLC or computer, with a built-in crop fertilizer requirement model and blending algorithm, as well as a dynamic mixing device equipped with a stirrer, and connected to a solid / liquid fertilizer replenishment silo and a metering addition device.

[0032] The integrated water and fertilizer unit includes an irrigation water source, an irrigation pump, an irrigation main pipeline, a fertilizer injection pump, an irrigation mother liquor tank, and a drip irrigation tape / micro-sprinkler network deployed in the field; the outlet of the dynamic mixing device is connected to the irrigation main pipeline through the fertilizer injection pump, or directly connected to the irrigation mother liquor tank.

[0033] Storage and buffering unit: A temporary storage tank for clear biogas slurry is set up after solid-liquid separation and before deep purification; a purified biogas slurry storage tank is set up after deep purification and before testing and blending, to buffer and ensure continuous operation of the system.

[0034] Its working process is as follows: The raw biogas slurry first enters a screen well to remove large debris, then enters a pH adjustment tank where the pH is adjusted to the neutral range by adding acid or alkali. Afterward, the biogas slurry is pumped into a screw press solid-liquid separator, where the separated biogas residue can be further composted to produce organic fertilizer, and the clarified biogas slurry enters a temporary storage tank.

[0035] The clarified liquid in the temporary storage tank is pumped to the purification sequence, where it first passes through a hydrocyclone desander to remove fine sand, and then sequentially through a sand filter and a disc filter for fine filtration. The filtered clarified liquid then enters the stabilization reaction tank, where it undergoes oxidation stabilization treatment for approximately 2 hours using micro-aeration.

[0036] The stabilized purified biogas slurry is stored in a storage tank. When fertilization begins, the purified biogas slurry is pumped into the detection and mixing unit. An online detection device analyzes its N, P, K concentrations, EC, and pH values ​​in real time, and the data is uploaded to the central control system. Based on the fertilizer requirements of the crops currently being irrigated, the system calculates the amount of potassium dihydrogen phosphate and potassium sulfate needed and controls the metering device to precisely add them from the fertilizer replenishment hopper to the dynamic mixing device, ensuring thorough mixing with the purified biogas slurry. During the mixing process, the EC / pH sensor monitors again, performing closed-loop fine-tuning to create a standard fertilizer solution.

[0037] Irrigation water is pumped from the water source, and standard fertilizer solution is injected into the main irrigation pipeline according to a set ratio through a fertilizer injection pump. After being mixed evenly in the pipeline, it is transported to the field irrigation network and delivered to the crops for precise water and fertilizer supply through drip emitters. The entire process, including start-up, shutdown, parameter adjustment, and fault alarms, is centrally monitored and automatically managed by the central control system.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A comprehensive utilization method combining biogas slurry and fertigation, characterized in that, Includes the following steps: S1 Pretreatment and solid-liquid separation of biogas slurry: The raw biogas slurry from the biogas slurry pond is subjected to solid-liquid separation to obtain clear biogas slurry and biogas residue. The pretreatment includes removing large debris through a screen and adjusting the pH of the biogas slurry. S2 Deep purification and stabilization of biogas slurry: The biogas slurry obtained in step S1 is sent to the deep purification unit, where fine sand and gravel are removed by a cyclone desanding device and suspended particulate matter is removed by a multi-layer filtration device with a filtration accuracy of not less than 120 mesh. Then it enters the stabilization reaction tank and is treated for a short time by aeration or the addition of stabilizers to reduce COD, BOD and possible reducing harmful substances in oxidation, so as to obtain purified and stabilized biogas slurry. S3 Online Nutrient Detection and Formula Adjustment: Real-time online detection of the main nutrients N, P, K, EC value, and pH value of the purified and stabilized biogas slurry obtained in step S2 is performed. Based on the fertilizer requirements of the target crop at the current growth stage, the types and amounts of fertilizers to be supplemented are calculated. S4 Precision Mixing and Fertilizer Solution Preparation: In the dynamic mixing device, the purified and stabilized biogas slurry is uniformly mixed with the fertilizer added according to the calculation results in step S3. During the mixing process, the EC and pH of the mixed fertilizer solution are monitored in real time and fine-tuned to prepare a standardized fertilizer solution that meets the requirements for irrigation and fertilization. S5 Precision application of integrated water and fertilizer: The standardized fertilizer solution prepared in step S4 is injected into the irrigation mother liquor tank of the integrated water and fertilizer system or directly injected into the main irrigation pipeline through the fertilizer injection pump in proportion. After being mixed with irrigation water in a preset ratio, it is delivered to the crop root area through field drip irrigation or micro-sprinkler irrigation network to achieve simultaneous and precise supply of water and fertilizer.

2. The comprehensive utilization method combining biogas slurry and fertigation as described in claim 1, characterized in that, The multi-layer filtration device in step S2 is a combination of a sand filter and a disc filter.

3. The comprehensive utilization method and equipment combining biogas slurry and fertigation as described in claim 1, characterized in that, The stabilizer in step S2 is hydrogen peroxide or sodium hypochlorite.

4. An integrated equipment for combining biogas slurry and fertigation to implement the method of claim 1, characterized in that, It includes a pretreatment unit, a deep purification and stabilization unit, a detection and blending unit, a water and fertilizer integration unit, and a storage and buffering unit connected sequentially along the material flow direction; The pretreatment unit includes a bar screen well, a pH adjustment tank, and a solid-liquid separator; The deep purification and stabilization unit includes a cyclone sand separator, at least one sand and gravel filter, a first-stage disc filter, and a subsequent stabilization reaction tank, all connected in sequence. The detection and mixing unit includes an online detection device, a central control system, and a dynamic mixing device; The integrated water and fertilizer unit includes an irrigation water source, an irrigation pump, an irrigation main pipeline, a fertilizer injection pump, an irrigation mother liquor tank, and a drip irrigation tape or micro-sprinkler network deployed in the field; the outlet of the dynamic mixing device is connected to the irrigation main pipeline through the fertilizer injection pump, or directly connected to the irrigation mother liquor tank. The storage and buffering unit includes a biogas slurry clear liquid temporary storage tank set after solid-liquid separation and before deep purification, and a purified biogas slurry storage tank set after deep purification and before testing and blending, for buffering and ensuring continuous operation of the system.

5. The integrated utilization equipment combining biogas slurry and water-fertilizer as described in claim 4, characterized in that, The solid-liquid separator is a screw extrusion separator.

6. The integrated utilization equipment combining biogas slurry and water-fertilizer as described in claim 4, characterized in that, The stabilization reaction tank is equipped with an aeration device or a dosing device.

7. The integrated utilization equipment combining biogas slurry and water-fertilizer as described in claim 4, characterized in that, The online detection device integrates at least an ammonia nitrogen / nitrate sensor, a potassium ion sensor, a pH sensor, and an EC sensor. The central control system is a PLC or computer with a built-in crop fertilizer requirement model and a mixing algorithm. The dynamic mixing device is equipped with a stirrer and is connected to a solid / liquid fertilizer replenishment silo and a metering and adding device.

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