Biogas slurry and biogas residue resource recycling integration method

Abstract

The invention relates to the technical field of biogas engineering, in particular to a biogas slurry and biogas residue resource recycling integration method. The process comprises the following steps: S1, carrying out solid-liquid separation on feces, and grinding and granulating solids to obtain fine feces; s2, feeding the liquid manure and the fine manure into an anaerobic fermentation system to produce biogas, biogas slurry and biogas residues; s3, putting biogas slurry and biogas residues and biomimetic enzyme into a biological thermal cracking reactor according to the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residues being greater than or equal to 1%, and performing pyrolysis at 100-120 DEG C for 3-6 hours to generate a liquid fertilizer raw material containing small organic molecules; s4, chelating and blending to obtain the high-added-value liquid organic fertilizer. Through collaborative process innovation of grinding pretreatment and medium-low-temperature thermal cracking, the resource utilization rate of the system is increased, full-chain substance and energy collaborative circulation of planting, breeding, fermentation, power generation and recycling is achieved, and the problems that a traditional biogas project is low in resource utilization rate, poor in economical efficiency and secondary pollution are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of biogas engineering, and in particular to an integrated method for recycling biogas slurry and biogas residue resources. Background Art

[0002] With the development of agricultural waste resource utilization and the circular economy, biogas projects have been widely used in rural areas of my country as an effective means of treating agricultural waste. Biogas energy has the advantages of being renewable, low-pollution, and widely distributed, making it an important technical measure for building a resource-saving and environmentally friendly society. However, existing rural biogas projects still face many problems in practical application: (1) Low level of resource utilization: In traditional biogas projects, biogas slurry and biogas residue are usually only directly applied as primary fertilizers without in-depth development, resulting in low added value and difficulty in meeting the demand for high-efficiency fertilizers in modern agriculture. (2) Poor economic efficiency: Due to the lack of output of high-value-added products, the operating costs of biogas projects are difficult to cover, and the economic benefits are poor, which limits their large-scale promotion. (3) Secondary pollution risk: Residual organic matter, pathogens and antibiotics in biogas slurry and biogas residue may cause pollution to soil and water bodies, and traditional treatment methods are difficult to completely eliminate these risks. (4) Insufficient system closure: In existing technologies, biogas projects often fail to form a complete material and energy cycle, and resource utilization is low.

[0003] In view of the above, an integrated method for the recycling of biogas slurry and residue resources is urgently needed to solve the problems of low resource utilization, poor economy and secondary pollution in traditional biogas projects. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides an integrated method for the resource recycling of biogas slurry and residue, realizing the coordinated circulation of materials and energy in the entire chain of "planting-breeding-fermentation-power generation-resource utilization", and solving the problems of low resource utilization, poor economy and secondary pollution of traditional biogas projects.

[0005] The technical method of the present invention to solve the above technical problems is as follows: An integrated method for recycling biogas slurry and biogas residue resources, comprising the following steps: S1. Manure pretreatment: The manure is separated into solid and liquid, and the solid part is granulated by a grinder to obtain fine manure; S2. Anaerobic fermentation to produce biogas: Liquid manure and fine manure enter the anaerobic fermentation system for fermentation reaction to produce biogas, biogas liquid and biogas residue; S3, biogas slurry and biogas residue thermal cracking treatment: the biogas slurry and biogas residue are put into a bio-thermal cracking reactor, and a biomimetic enzyme is put into the bio-thermal cracking reactor to carry out a bio-thermal cracking reaction, wherein the weight ratio of the biomimetic enzyme to the dry weight of the biogas residue is greater than or equal to 1%, the reaction temperature is 100-120° C., and the reaction time is 3-6 hours to obtain a liquid fertilizer raw material; Wherein, the biomimetic enzyme is an artificial synthetic material that simulates the catalytic function of natural enzymes; S4. Liquid organic fertilizer production and recycling: Liquid fertilizer raw materials are chelated and formulated to produce high value-added liquid organic fertilizer.

[0006] On the basis of the above technical method, the present invention can also be improved as follows.

[0007] Preferably, the biomimetic compound enzyme is prepared by mixing three commercial biomimetic enzymes, namely C enzyme, L enzyme and T enzyme, in a certain ratio. The mixing ratio of the three enzymes, namely C enzyme, L enzyme and T enzyme, is (1-2): (1-2): (1-2).

[0008] Enzyme C is CelluMax HT from NIO Biotech, which is mainly a cellulase; The L enzyme is LignoMax TH from Meihua Biotechnology, which includes cellulase and phenol oxidation and polymerization enzymes; The T enzyme is Yiduoli's Thermozyme, which contains cellulase, phenol oxidase and protein degrading enzyme.

[0009] Among them, cellulose-degrading bionic enzymes are used to break cellulose chains and assist in lignin depolymerization; protein-degrading bionic enzymes are used to cut the peptide bonds of proteins in sludge to generate short peptides and amino acids; phenolic oxidation and polymerization bionic enzymes are used for lignin degradation and humic acid condensation.

[0010] Preferably, in S3, the weight ratio of the biomimetic enzyme to the dry weight of the biogas residue is 1-3%.

[0011] Preferably, in S2, before the liquid manure and fine manure enter the anaerobic fermentation system, the process further includes: performing anaerobic ammonia oxidation pretreatment on the liquid manure before entering the anaerobic fermentation system.

[0012] Preferably, in S1, the particle size of the fine material manure is ≤2 mm.

[0013] Preferably, the biogas produced in S2 is purified and used for power generation, and part of the generated electricity is used to supply energy for the grinder for manure pretreatment in S1 and the biothermal cracking reactor in S3, and the surplus electricity is connected to the grid.

[0014] Preferably, in step S4, the liquid fertilizer raw material is subjected to chelation and preparation of nitrogen, phosphorus and potassium elements to obtain high value-added liquid organic fertilizer.

[0015] Preferably, the manure in S1 is collected from the breeding end.

[0016] Preferably, the high value-added liquid organic fertilizer obtained in step S4 is replenished to the soil at the planting end through a drip irrigation system.

[0017] Preferably, the crop straw or residues produced at the planting end are input to the breeding end as breeding feed or bedding.

[0018] The specific principle of the thermal cracking process of the present invention is: heating the biogas slurry and residue to 100-120℃, and under the action of biomimetic enzymes, accelerating the cell wall rupture and the breaking of macromolecular chemical bonds in the biogas residue, to produce a fertilizer stock solution rich in humic acid and small molecular organic matter.

[0019] The reaction process mainly includes three stages: cell wall disruption stage (high temperature weakens the cell wall structure, biomimetic enzymes are targeted to supply the cell membrane, and accelerate the release of cell contents), macromolecule decomposition stage (organic macromolecules generate organic small molecules under the action of biomimetic enzymes), and condensation and humification stage (condensation into small molecules such as humic acid).

[0020] The beneficial effects of the present invention are: 1. The present invention realizes the efficient resource utilization of biogas slurry and biogas residue through the collaborative process innovation of "grinding pretreatment + medium and low temperature thermal cracking". Special grinding equipment is used at the front end to granulate the manure, significantly increasing the specific surface area and providing an ideal reaction interface for subsequent thermal cracking; at the back end, under medium and low temperature conditions of 100-120°C, a special bio-enzyme catalyst is used to improve the degradation efficiency of organic matter. Compared with high-temperature thermal cracking, this combined process is more energy-efficient, and compared with microbial fermentation, the processing time is shortened from 30 days to less than 6 hours. The organic matter content in the product reaches 13-15%, the humic acid content exceeds 6%, and the total nutrient content exceeds 6%. The value of the liquid organic fertilizer produced is increased by 2-3 times. At the same time, the process decomposes thoroughly. Under the premise of ensuring the treatment effect, it can operate stably only with the system's own biogas power supply, achieving a perfect balance between economy and environmental protection.

[0021] 2. Through its innovative design, this invention integrates planting, breeding, energy production, and fertilizer processing into an organic, unified closed-loop system. Grinding pretreatment is used at the front end to enhance the reactivity of manure, while anaerobic fermentation is optimized in the middle to improve gas production efficiency. Low- and medium-temperature thermal cracking technology is used at the back end to efficiently convert biogas slurry and residue, ultimately forming a complete material and energy cycle of "planting-breeding-fermentation-power generation-resource utilization." This design transcends the single-point technical limitations of traditional biogas projects, improves system resource utilization, and truly realizes the full utilization of agricultural waste.

[0022] 3. This invention innovatively creates a two-way circulation mechanism for materials and energy: Biogas power generation prioritizes the system's own electricity needs, with excess power connected to the grid to generate revenue, achieving 100% energy self-sufficiency. Furthermore, high-quality liquid fertilizer is recycled for crop production through intelligent drip irrigation, forming a closed loop of manure-biogas-fertilizer-crops, improving the soil environment and increasing crop yields. This two-way circulation design significantly outperforms traditional treatment methods in terms of economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an architectural diagram of the integrated method for recycling biogas slurry and biogas residue resources according to the present invention; DETAILED DESCRIPTION The principles and features of the present invention are described below. The examples provided are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] In the following examples and comparative examples, enzyme C is CelluMax HT from NIO Biotech, which is mainly a cellulase; The L enzyme is LignoMax TH from Meihua Biotechnology, which includes cellulase and phenol oxidation and polymerization enzymes; The T enzyme is Yiduoli's Thermozyme, which contains cellulase, phenol oxidase and protein degrading enzyme.

[0025] Example 1 An integrated method for recycling biogas slurry and biogas residue resources, comprising the following steps: S1. Manure pretreatment: Manure generated at the aquaculture end is collected and subjected to solid-liquid separation. The solid portion is granulated in a grinder to obtain fine manure. The particle size of the fine manure is ≤2mm. S2. Anaerobic fermentation to produce biogas: Liquid manure and fine manure enter the anaerobic fermentation system for fermentation reaction to produce biogas, biogas liquid and biogas residue. The liquid is pre-treated by anaerobic ammonium oxidation before entering the anaerobic fermentation system; S3, biogas slurry and biogas residue thermal cracking treatment: the biogas slurry and biogas residue are put into a bio-thermal cracking reactor, and the bio-biomimetic enzyme is put into the bio-thermal cracking reactor to carry out a bio-thermal cracking reaction to obtain a liquid fertilizer raw material; S4. Production and recycling of liquid organic fertilizer: The nitrogen, phosphorus and potassium elements in the liquid fertilizer raw materials are chelated and formulated to produce high-value-added liquid organic fertilizer, which is replenished to the soil at the planting end through a drip irrigation system; the crop straw or residues produced at the planting end are input into the breeding end as livestock feed or bedding.

[0026] Among them, the biogas produced in S2 is purified and used for power generation. Part of the generated electricity is used to supply energy for the grinder for manure pretreatment in S1 and the bio-thermal cracking reactor in S3, and the remaining electricity is connected to the grid.

[0027] In step S3, The biomimetic enzyme is prepared by mixing three commercial biomimetic enzymes, namely, C enzyme, L enzyme and T enzyme, in a certain ratio, wherein the mixing ratio of the three enzymes is 1:1:2.

[0028] The weight ratio of biogas slurry to biogas residue is 1:3; The weight ratio of biomimetic enzyme dosage to dry weight of biogas residue is: 2%; The particle size of fine manure is: ≤2mm; The reaction temperature is 110°C; The reaction time was 4 hours.

[0029] The liquid fertilizer raw material obtained in step S3 is tested: Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 14%, humic acid content 7%.

[0030] Example 2 The only difference between this embodiment and embodiment 1 is that in step S3, the reaction temperature is 120°C.

[0031] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 15%, humic acid content 8%.

[0032] Example 3 The only difference between this embodiment and embodiment 1 is that in step S3, the reaction temperature is 100°C.

[0033] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 13%, humic acid content 6%.

[0034] Example 4 The only difference between this embodiment and embodiment 1 is that in step S3, the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residue is 1%.

[0035] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 7%, organic matter content 13%, humic acid content 6%.

[0036] Example 5 The only difference between this embodiment and embodiment 1 is that in step S3, the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residue is 3%.

[0037] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 15%, humic acid content 8%.

[0038] Example 6 The only difference between this embodiment and embodiment 1 is that in step S3, the reaction time is 6 hours.

[0039] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 15%, humic acid content 8%.

[0040] Example 7 The only difference between this embodiment and embodiment 1 is that in step S3, the reaction time is 3 hours.

[0041] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 6%, organic matter content 13%, humic acid content 6%.

[0042] Example 8 The only difference between this embodiment and embodiment 1 is that in step S3, the reaction temperature is 100° C., the reaction time is 3 h, and the weight ratio of the biomimetic enzyme to the dry weight of the biogas residue is 1%.

[0043] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 5%, organic matter content 13%, humic acid content 6%.

[0044] Example 9 The only difference between this embodiment and embodiment 1 is that in step S3, the three enzymes C enzyme, L enzyme and T enzyme are mixed in a ratio of 1:1:2.

[0045] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Slurry Fertilizer"; Test results: total nutrients 7%, organic matter content 13%, humic acid content 8%.

[0046] Comparative Example 1 The only difference between this comparative example and Example 1 is that in step S3, the reaction temperature is 80°C.

[0047] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 4%, organic matter content 7%, humic acid content 3%.

[0048] Comparative Example 2 The only difference between this comparative example and Example 1 is that in step S3, the reaction temperature is 140°C.

[0049] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 15%, humic acid content 8%.

[0050] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step S3, the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residue is 0.5%.

[0051] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 4%, organic matter content 8%, humic acid content 4%.

[0052] Comparative Example 4 The only difference between this comparative example and Example 1 is that in step S3, the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residue is 4%.

[0053] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 15%, humic acid content 8% Comparative Example 5 The only difference between this comparative example and Example 1 is that in step S3, the reaction temperature is 2 hours.

[0054] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 5%, organic matter content 10%, humic acid content 5%.

[0055] Comparative Example 6 The only difference between this comparative example and Example 1 is that in step S3, the reaction temperature is 7 hours.

[0056] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Methane Fertilizer"; Test results: total nutrients 8%, organic matter content 16%, humic acid content 8%.

[0057] Comparative Example 7 The only difference between this comparative example and Example 1 is that in step S3, the biomimetic enzyme is missing.

[0058] In step S3, since no biomimetic enzyme is added, the reaction is not started and liquid fertilizer raw material cannot be generated.

[0059] Comparative Example 8 The only difference between this comparative example and Example 1 is that in step S1, the particle size of the fine manure is: ≤5 mm.

[0060] The liquid fertilizer raw material obtained in step S3 is tested, Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Slurry Fertilizer"; Test results: total nutrients 4%, organic matter content 8%, humic acid content 4%.

[0061] Comparative Example 9 The only difference between this comparative example and Example 1 is that in step S3, the three enzymes C enzyme, L enzyme and T enzyme are mixed in a ratio of 1:1:0.

[0062] The liquid fertilizer raw material obtained in step S3 is tested; Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Slurry Fertilizer"; Test results: total nutrients 6%, organic matter content 11%, humic acid content 6%.

[0063] Comparative Example 10 The only difference between this comparative example and Example 1 is that in step S3, the three enzymes C enzyme, L enzyme and T enzyme are mixed in a ratio of 1:0:1.

[0064] The liquid fertilizer raw material obtained in step S3 is tested; Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Biogas Fertilizer"; Test results: total nutrients 4%, organic matter content 9%, humic acid content 4%.

[0065] Comparative Example 11 The only difference between this comparative example and Example 1 is that in step S3, the ratio of the three enzymes, enzyme C, enzyme L and enzyme T, is 0:1:1.

[0066] The liquid fertilizer raw material obtained in step S3 is tested; Test methods: Total nutrients (nitrogen - Kjeldahl method GB / T 19203-2008, phosphorus - molybdenum antimony antimony spectrophotometry GB / T 11893-1989, potassium - flame photometry GB / T 17767.1-1999), organic matter, and humic acid content (potassium dichromate volumetric method NY / T 1121.6-2006); Test standards: NY 525-2021 "Organic Fertilizer", NY / T2596-2014 "Slurry Fertilizer"; Test results: total nutrients 5%, organic matter content 10%, humic acid content 7%.

[0067] Table 1 shows the performance test results of various liquid fertilizer raw materials:

[0068] From the data analysis in Table 1, we can see that: Temperature Analysis: Temperature significantly impacts organic matter conversion efficiency. Examples 1 (110°C), 2 (120°C), and 3 (100°C) show that within the 100-120°C range, total nutrients stabilized at around 8%, organic matter content was 13-15%, and humic acid content was 6-8%. In contrast, Comparative Example 1 (80°C) showed only 4% total nutrients, indicating insufficient reaction activity below 100°C. While Comparative Example 2 (140°C) achieved comparable performance to the high-temperature group, the increased energy consumption and the need for high-pressure equipment compromised economic efficiency. This suggests that 100-120°C represents the optimal temperature window for thermal cracking, ensuring efficient organic matter degradation while avoiding the equipment and energy consumption challenges associated with high temperatures.

[0069] Reaction time analysis: Reaction time and product quality exhibit a nonlinear relationship. Examples 1 (4 hours), 6 (6 hours), and 7 (3 hours) demonstrate that total nutrients reach 6% or higher when the reaction time is ≥3 hours, with the optimal nutrient content of 8% and organic matter content of 15% achieved between 4 and 6 hours. In contrast, in Comparative Example 5 (2 hours), total nutrients plummeted to 5%, indicating that 3 hours is the critical time for complete cell wall disruption and macromolecular decomposition. Comparative Example 6 (7 hours) showed no significant improvement, indicating that the reaction reached saturation after 6 hours. This suggests that 3-6 hours represents an economical time window: too short a time window results in an incomplete reaction, while too long a time window leads to diminishing marginal returns.

[0070] Analysis of Biomimetic Enzyme Dosage: Biomimetic enzymes are indispensable. Enzyme addition is positively correlated with product quality, but a threshold effect exists. Examples 1 (2%), 4 (1%), and 5 (3%) show that increasing the enzyme dosage from 1% to 3% increases total nutrients from 7% to 8%, and humic acid from 6% to 8%. This is in contrast to Comparative Example 3 (0.5%), where the indicators are halved, indicating that 1% is the critical value for catalytic activation. Comparative Example 4 (4%) produces no additional gain, suggesting that 3% approaches the saturation point of the enzymatic reaction. Therefore, an addition ratio of 1-3% ensures catalytic efficiency while avoiding the costly waste of excessive enzyme preparation. In Comparative Example 7, the reaction fails without enzyme, validating its catalytic activity and demonstrating the necessity of biomimetic enzymes.

[0071] Analysis of the ratio of three biomimetic enzymes: C enzyme (cellulose degradation), L enzyme (lignin degradation and humic acid condensation), and T enzyme (protein degradation and phenolic oxidation) working synergistically in a ratio of 1:1:2 yields optimal total nutrient, organic matter, and humic acid content in liquid fertilizer (7-8% total nutrients, 13-14% organic matter, and 7-8% humic acid). The absence of any enzyme or an imbalance in the ratio significantly reduces fertilizer efficiency. L and T enzymes are crucial for humic acid synthesis. Even without C enzyme (Comparative Example 11), humic acid content remains at 7%, but total nutrient and organic matter levels decrease due to insufficient cellulose degradation. This rationally designed ratio effectively improves the resource utilization of biogas slurry and residue.

[0072] Manure Particle Size Analysis: Particle size control is a core element of pretreatment. Example 1 (≤2 mm) yielded 8% total nutrients and 14% organic matter, while Comparative Example 8 (5 mm) saw these values ​​drop to 4% and 8%, respectively, a difference of over 50%. This is because fine particle size increases the specific surface area, significantly improving the contact efficiency between the enzyme and the substrate. Data demonstrates that a particle size of ≤2 mm is essential for ensuring the interfacial effect of the thermal cracking reaction; exceeding this limit leads to a sharp drop in mass transfer efficiency.

[0073] Table 2 is a comparison of various fertilizer production technologies

[0074] Currently, several ways of resource utilization of biogas slurry and residue are shown in Appendix 2. The bio-thermal cracking technology adopted in this patent has a faster reaction rate and a shorter production time than microbial fermentation and natural fermentation. Through nutrient blending processes such as nitrogen, phosphorus and potassium chelation technology, it produces liquid organic fertilizer with high added value. However, the water-soluble conversion rate of organic carbon in fertilizers produced by microorganisms and natural fermentation is very low, and the soil improvement effect is slow.

[0075] The water-soluble organic carbon conversion rate refers to the proportion of carbon in organic matter (such as straw, livestock and poultry manure, and compost) converted to water-soluble carbon (such as dissolved organic carbon, DOC) under specific conditions (such as hydrolysis or microbial action). The water-soluble organic carbon conversion rates for the various fertilizers listed in Table 2 were determined as follows: solid organic particles were first crushed to a particle size of less than 2 mm. Total organic carbon (TOC) was measured using the potassium dichromate volumetric method (GB / T 17134-1997). Dissolved organic matter (DOC) in the fertilizer was then determined using the o-phenanthroline colorimetric method. The water-soluble conversion rate is calculated as: DOC concentration × volume of extracted fertilizer solution / (mass of solid organic sample × TOC content) × 100%.

[0076] This technology operates within a temperature range of 100-120°C, and combined with biomimetic enzymes, it can achieve efficient and rapid resource utilization. While increasing temperature can accelerate the thermal cracking process, it also has two negative consequences: First, the pressure in the reaction vessel increases, necessitating the use of high-temperature, high-pressure vessels, which are more expensive and less safe. Second, the increased temperature increases energy consumption, making it impossible to achieve energy self-sufficiency in resource utilization for biogas projects.

[0077] Thermal cracking at higher temperatures (above 300°C) can produce sludge biochar. However, biochar production technology requires high pyrolysis temperatures, consumes a large amount of high-grade energy, and has poor reaction stability at high temperatures, and a relatively mature technology has not yet been formed. In addition, my country's land use laws and regulations on sludge charcoal are still not perfect. Therefore, biochar should not be applied to soil without physical and chemical analysis, pollutant content and biochar toxicity testing.

[0078] This patented technology significantly improves the resource utilization efficiency of biogas slurry and residue through a synergistic process combining grinding pretreatment, medium- and low-temperature thermal cracking, and biomimetic enzyme catalysis. Experimental data validates the feasibility of this technology approach, and the rational selection of parameters (temperature, time, and enzyme dosage) enables the stable production of high-value-added liquid organic fertilizer with low energy consumption, meeting the needs of a circular economy.

[0079] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] 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 in the scope of protection of the present invention.

Claims

1. An integrated method for recycling biogas slurry and biogas residue resources, characterized in that: The following steps are involved: S1. Manure pretreatment: The manure is separated into solid and liquid, and the solid part is granulated by a grinder to obtain fine manure; S2. Anaerobic fermentation to produce biogas: Liquid manure and fine manure enter the anaerobic fermentation system for fermentation reaction to produce biogas, biogas liquid and biogas residue; S3, biogas slurry and biogas residue thermal cracking treatment: the biogas slurry and biogas residue are put into a bio-thermal cracking reactor, and a biomimetic enzyme is put into the bio-thermal cracking reactor to carry out a bio-thermal cracking reaction, wherein the weight ratio of the biomimetic enzyme to the dry weight of the biogas residue is greater than or equal to 1%, the reaction temperature is 100-120° C., and the reaction time is 3-6 hours to obtain a liquid fertilizer raw material; Wherein, the biomimetic enzyme is an artificial synthetic material that simulates the catalytic function of natural enzymes; S4. Liquid organic fertilizer production and recycling: Liquid fertilizer raw materials are chelated and formulated to produce high value-added liquid organic fertilizer.

2. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that: In S3, the biomimetic compound enzyme is prepared by mixing three commercial biomimetic enzymes, namely, C enzyme, L enzyme and T enzyme, in a certain ratio. The mixing ratio of the three enzymes, namely, C enzyme, L enzyme and T enzyme, is (1-2): (1-2): (1-2).

3. The integrated method for recycling biogas slurry and biogas residue resources according to claim 2 is characterized in that: In S3, the weight ratio of the biomimetic enzyme dosage to the dry weight of the biogas residue is 1-3%.

4. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that: In S2, before the liquid manure and fine manure enter the anaerobic fermentation system, the process also includes: performing anaerobic ammonia oxidation pretreatment on the liquid manure before entering the anaerobic fermentation system.

5. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that: In S1, the particle size of the fine material manure is ≤2mm.

6. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that: The biogas produced in S2 is purified and used to generate electricity. Part of the generated electricity is used to supply energy to the grinder for manure pretreatment in S1 and the bio-thermal cracking reactor in S3, and the remaining electricity is connected to the grid.

7. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that, in step S4, nitrogen, phosphorus and potassium elements are chelated and formulated on the liquid fertilizer raw material to produce high-value-added liquid organic fertilizer.

8. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 is characterized in that: The manure in S1 is collected from the breeding end.

9. The integrated method for recycling biogas slurry and biogas residue resources according to claim 1 or 7, characterized in that: The high-value-added liquid organic fertilizer obtained in step S4 is replenished to the soil at the planting end through a drip irrigation system.

10. The integrated method for recycling biogas slurry and biogas residue resources according to claim 9, characterized in that: The crop straw or residues produced at the planting end are input into the breeding end as feed or bedding.

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