A method for preparing modified protein raw materials by livestock and poultry manure high-temperature self-produced steam degradation

Abstract

This invention discloses a method for preparing modified protein raw materials from livestock and poultry manure through high-temperature self-generated steam degradation, relating to the field of livestock and poultry manure treatment technology. The method involves screening fresh livestock and poultry manure to remove impurities, conditioning it to a moisture content of 70%–80%, preheating it in a preheating furnace at low temperature, and mechanically breaking down the manure walls before sequentially feeding it into two drying furnaces connected in series. A combustion furnace injects steam from one end of each drying furnace, creating a gradient temperature zone within the furnace. Steam is generated by the in-situ evaporation of moisture from the material itself and discharged into the air, creating a low-oxygen atmosphere. The material simultaneously undergoes dehydration and modified protein conversion. The first-stage drying process involves a retention time of 7–8 minutes, resulting in an output moisture content of 35%–45%; the second-stage drying process involves a retention time of 8–10 minutes, resulting in an output moisture content of 8%–12%. Finally, after impurity removal and drying, modified protein raw materials are obtained. This invention eliminates the need for external steam sources, avoiding the problems of hard crust formation and insufficient steam in single-furnace processes. It achieves complete degradation of uric acid and animal drug residues, producing a modified protein content ≥35%, suitable as feed or organic fertilizer raw material, and is suitable for large-scale continuous production.

Description

Technical Field

[0001] This invention relates to the field of livestock and poultry manure treatment technology, specifically a method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure. Background Technology

[0003] Existing high-temperature drying technologies for livestock and poultry manure typically employ a single drying oven for dehydration. To degrade harmful substances such as uric acid and antibiotics, the residence time of the material in the oven needs to be extended. However, this leads to a rapid hardening of the material surface, making it difficult for internal moisture to escape, resulting in insufficient steam output and an inability to create a stable degradation reaction atmosphere. Furthermore, it easily causes localized gelatinization and carbonization of the material. Maintaining normal drying speed and time only achieves preliminary dehydration, with the product primarily used as raw material for organic fertilizer or solid fuel. It cannot achieve targeted modification and high-value conversion of protein components, and the detoxification process is incomplete, resulting in low antibiotic residue degradation rates and high non-protein nitrogen content, making it unsuitable as a protein raw material.

[0004] In addition, existing high-temperature hydrolysis modification processes for livestock and poultry manure mostly require external boilers to provide external steam, resulting in large equipment investment, high energy consumption, and the inability to form a continuous and integrated processing system with existing drying equipment. The cost of modification is high, and it is difficult to adapt to existing equipment to achieve large-scale industrial application.

[0005] Therefore, the industry urgently needs a treatment method that can achieve high-value conversion of livestock and poultry manure, strong feed stability, full utilization of waste heat, and thorough harmlessness, so as to fundamentally solve the pain points of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure. This method is based on the livestock and poultry manure drying and treatment mechanism authorized by CN120289062B. By adding a conditioning and drying furnace to construct a two-stage drying system, and matching it with a gradient temperature zone high-temperature self-generated steam hydrolysis process, the conversion of livestock and poultry manure from low-value-added drying products to high-value modified protein powder is realized without changing the core structure of the original equipment or requiring large-scale modification. At the same time, it solves the problems of poor adaptability to fluctuations in raw material moisture content, insufficient utilization of waste heat, and unstable hydrolysis reaction, forming a continuous treatment method that integrates efficient dehydration, precise conditioning, deep modification, thorough harmlessness, and closed-loop energy utilization.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure, characterized by comprising the following steps: Step 1, raw material pretreatment: Fresh livestock and poultry manure is screened to remove impurities, stirred and conditioned to a moisture content of 70%~80%, and then sent to the preheating furnace; the combustion furnace is started to heat the drying furnace, and the hot exhaust gas generated by the drying furnace is sent to the jacket cavity of the preheating furnace after being dusted by a cyclone dust collector. The material is stirred, sheared and pushed in the preheating furnace by the stirring components to achieve low temperature preheating and mechanical cell wall breaking. Step Two, Primary High-Temperature Low-Oxygen Dehydration and Degradation: The preheated material is fed into the first drying oven. An open flame is injected from one end of the first drying oven, with an inlet temperature of 800℃~1100℃. A gradient temperature zone of 800℃ to 400℃ is formed inside the oven along the material's direction of travel. The material is evenly coated onto the high-temperature inner wall of the drying oven by a stirring component with a trowel, completing dehydration. The material's own moisture evaporates in situ, generating a large amount of steam, which is discharged from the oven to create a low-oxygen reaction atmosphere. Under the action of boiling with water, the temperature of the material is stably maintained at 100~110℃ without gelatinization. Under the combined action of the gradient high temperature, self-generated steam, and low oxygen in the oven, preliminary dehydration and the first stage of degradation and modification are completed simultaneously. The material stays in the first drying oven for 7~8 minutes, and the output moisture content is controlled at 35%~45%. Step 3, Secondary High-Temperature Low-Oxygen Deep Dehydration and Degradation: The material dried in the first stage is sent to the second drying furnace through a closed conveyor pipe. An open flame is injected from one end of the second drying furnace, creating a gradient temperature zone of 800℃ to 400℃ along the material's direction of travel. The material is evenly coated onto the high-temperature inner wall of the drying furnace by a stirring component with a trowel, continuing dehydration. The remaining moisture in the material continues to evaporate in situ, generating steam and maintaining a low-oxygen reaction atmosphere inside the furnace. The material temperature remains stable at 100~110℃ without gelatinization. Under the combined effects of the gradient high temperature, self-generated steam, and low oxygen in the furnace, deep dehydration and the second stage of degradation and modification are completed simultaneously. The material remains in the second drying furnace for 8~10 minutes, and the output moisture content is controlled at 8%~13%. Step 4, Waste heat recovery and exhaust gas treatment: The waste heat exhaust gas generated by the first and second drying ovens is cyclone dust collector, part of which is sent to the preheating oven as a preheating heat source, and the other part is recovered by the heat exchanger and then sent to the dust removal spray tower for treatment to meet the emission standards. Step 5, finished product preparation: The material that has undergone two-stage simultaneous dehydration and degradation modification is removed and dried to adjust the moisture content to below 14%. After cooling, the finished product containing modified protein is obtained.

[0008] Preferably, in step one, the fresh livestock and poultry manure is fresh chicken manure from a large-scale farm, and the initial moisture content of the raw material is best at 70%~71%.

[0009] Preferably, the residence time of the material in the cavity section corresponding to the temperature range of 400~600℃ in each drying oven is not less than 2.5 minutes, and the total residence time of the two stages is not less than 5 minutes.

[0010] Preferably, during the modified protein conversion process in steps two and three, the macromolecular proteins in the material are gradually degraded into small molecule peptides and free amino acids, the non-protein nitrogen of urate in the material undergoes heterocyclic ring opening and directional conversion into amino acid nitrogen, and the residues of tetracycline, quinolone, and sulfonamide aquaculture drugs are completely degraded.

[0011] Preferably, the self-generated high-temperature steam in the first and second drying ovens is the only steam source for the corresponding reaction process in the oven, and no external steam or water source is required throughout the process.

[0012] A modified protein raw material from livestock and poultry manure is prepared by the method described in any one of claims 1 to 6, wherein the modified protein raw material has a moisture content of ≤14%, a modified protein content of ≥35%, and a non-protein nitrogen content of ≤0.3%.

[0013] Compared with the prior art, the beneficial effects of the present invention are: The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure: The dual-furnace, phased humidity control completely solves the defects of the single-furnace process. By using two identical drying furnaces to carry out dehydration and degradation in stages, the material residence time in each furnace is controlled within a reasonable range. This avoids the problems of material surface hardening, difficulty in removing internal moisture, and insufficient steam output caused by prolonged residence time in a single furnace. It ensures the continuous and stable steam supply required for drying effect and degradation reaction, while effectively preventing material gelatinization and carbonization.

[0014] High-temperature, low-oxygen self-generated steam degradation is energy-efficient and has a simple process. It utilizes the in-situ evaporation of moisture from the material itself to generate high-temperature steam, which is then discharged from the furnace to create a low-oxygen reaction atmosphere. No external steam or water source is required throughout the process. An open flame is directly injected into the combustion furnace to provide a heat source, creating a gradient temperature zone from 800°C to 400°C inside the furnace. The material temperature is stably maintained at 100~110°C under the action of boiling with water. Under the combined effect of gradient high temperature, self-generated steam, and low oxygen, dehydration and degradation modification are completed simultaneously. The overall energy consumption of the system is reduced by more than 30% compared to the existing external steam hydrolysis process.

[0015] Thoroughly harmless and highly safe, the dual action of two-stage high-temperature and low-oxygen steam degradation can achieve a ≥99% kill rate of roundworm eggs, a ≥99.9% kill rate of pathogenic bacteria such as E. coli and Salmonella, and complete degradation of aquaculture drug residues such as tetracyclines, quinolones, and sulfonamides. At the same time, it can convert organically bound heavy metals in materials into stable inorganic forms, significantly reducing their biotoxicity and environmental migration risks. The products fully comply with national safety standards for feed raw materials and organic fertilizer raw materials. Detailed Implementation

[0016] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments and comparative examples. The described embodiments are only some preferred embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Based on the patent authorized announcement number CN120289062B, which discloses a livestock and poultry manure drying and treatment mechanism, a conditioning drying furnace 3 and a gradient temperature zone high-temperature hydrolysis reactor 4 are added. The discharge port of the drying furnace 2 is connected to the inlet of the conditioning drying furnace 3 through a closed spiral conveying pipe. The discharge port of the conditioning drying furnace 3 is connected to the inlet of the high-temperature hydrolysis reactor 4 through a closed pipe. The exhaust gas outlet of the high-temperature hydrolysis reactor 4 is connected to the heating inlet of the conditioning drying furnace 3 in a closed connection. The exhaust gas outlet of the conditioning drying furnace 3 is connected to the inlet of the heat exchanger 6, forming a complete continuous treatment system. Example

[0018] This embodiment provides a method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure, which is strictly implemented in accordance with the core parameters of the claims. The specific steps are as follows: Raw material pretreatment: Fresh chicken manure from large-scale egg-laying chicken farms is selected as raw material. It is screened by drum screen to remove large impurities such as sand and gravel. The mixture is stirred and conditioned to a moisture content of 75% and then sent to the preheating furnace. The combustion furnace is started to heat two drying furnaces. The hot exhaust gas generated by the drying furnace is sent to the jacket cavity of the preheating furnace after being dusted by a cyclone dust collector. The material is continuously stirred, sheared and pushed in the preheating furnace by the stirring components to complete the 50℃ low-temperature preheating and mechanical cell wall breaking, which destroys the water adsorption and water-holding structure of the manure matrix and releases the internal bound water. The material stays in the preheating furnace for 8 minutes and the discharge temperature is controlled at 55℃.

[0019] First-stage high-temperature low-oxygen dehydration and degradation: Preheated material is fed into the first drying oven through a material conveying pipeline. An open flame is injected from one end of the first drying oven at an inlet temperature of 1000℃, creating a gradient temperature zone from 800℃ to 400℃ along the material's direction of travel within the oven. A stirring assembly with a trowel inside the drying oven evenly coats the material onto the high-temperature inner wall, expanding the contact area between the material and hot air for rapid dehydration. The material's own moisture evaporates in situ, generating a large amount of steam, which is expelled from the oven to create a low-oxygen reaction atmosphere. Under the action of boiling with water, the material's temperature is stably maintained at 105℃ without gelatinization. Under the combined effects of the gradient high temperature, self-generated steam, and low oxygen within the oven, preliminary dehydration and the first stage of modified protein conversion are completed simultaneously. The material remains in the first drying oven for 7 minutes, with the discharge moisture content controlled at 40%.

[0020] Secondary high-temperature low-oxygen deep dehydration and degradation: The material dried in the first stage is sent to the second drying furnace through a closed spiral conveyor pipe. An open flame is injected from one end of the second drying furnace, with an inlet temperature of 1000℃. A gradient temperature zone of 800℃ to 400℃ is formed inside the furnace along the material's direction of travel. The material is evenly coated onto the high-temperature inner wall of the drying furnace by a stirring component with a trowel inside the furnace for further dehydration. The remaining moisture in the material continues to evaporate in situ to generate steam, maintaining a low-oxygen reaction atmosphere inside the furnace. The material temperature remains stable at 105℃ without gelatinization. Under the combined effect of the gradient high temperature, self-generated steam, and low oxygen inside the furnace, deep dehydration and the second-stage modified protein conversion are completed simultaneously. The material stays in the second drying furnace for 10 minutes, and the moisture content of the discharged material is controlled at 10%.

[0021] Waste heat recovery and exhaust gas treatment: The waste heat exhaust gas generated by the first and second drying ovens is cyclone dust collector, and part of it is sent to the preheating oven as a preheating heat source. The other part is recovered by the heat exchanger and then sent to the dust removal spray tower. After spraying to reduce dust and deodorize, it is discharged in compliance with standards. There is no odor overflow, no dust pollution and no wastewater discharge throughout the process.

[0022] Product preparation: The material that has undergone two-stage simultaneous dehydration and degradation modification is passed through a grading and screening machine to remove residual inorganic inert impurities, and then the moisture content is precisely controlled to 12.5% ​​by a low-temperature dryer. After cooling, it is sent to the finished product storage silo to obtain the modified protein raw material from livestock and poultry waste.

[0023] The modified protein raw material prepared in this embodiment, after testing by a third-party authoritative institution, has the following core indicators: Nutritional indicators: Modified protein content 35.2%, non-protein nitrogen content 0.3%; Hygiene and safety indicators: Salmonella, Escherichia coli, Staphylococcus aureus, and Aspergillus flavus were not detected; the ascarid egg kill rate was ≥99.9%; tetracyclines, quinolones, and sulfonamides were not detected. Environmental safety indicators: The conversion rate of organically bound heavy metals is ≥98%, which meets the national safety standards of the "Feed Raw Material Catalog" and "Organic Fertilizer". Physicochemical indicators: Moisture content 12.5%, no mold or clumping after 6 months of sealed storage at room temperature, meeting safe storage requirements. Example

[0024] The core difference between this embodiment and Embodiment 1 lies in adapting to fluctuations in the upper limit of raw material moisture content, strictly adhering to the raw material moisture content range of 65%~75% as described in the claims, as detailed below: The raw material is fresh chicken manure from large-scale egg-laying chicken farms. After screening and impurity removal, the initial moisture content of the raw material is 75%. During the pretreatment stage, the raw material is stirred and conditioned to a moisture content of 80%. The residence time in the preheating furnace is 5 minutes, and the discharge temperature rises to 60℃. The first drying oven has an inlet temperature of 950℃, a material residence time of 8 minutes, and after primary drying, the material moisture content drops to 45%, and the outlet temperature is maintained at 110℃. The second drying oven has an inlet temperature of 950℃, a material residence time of 8 minutes, and after secondary drying, the material moisture content drops to 12%, and the outlet temperature is maintained at 110℃. The total material processing time is 23 minutes.

[0025] The modified protein raw material prepared in this embodiment has the following key indicators after testing: modified protein content 35.0%, non-protein nitrogen content 0.29%, pathogenic bacteria, ascarid eggs, and antibiotic residues were not detected, organically bound heavy metal conversion rate 98.1%, and moisture content 13.2%, which verifies the strong adaptability of the process to fluctuations in the moisture content of the raw material. Example

[0026] This embodiment is a large-scale industrial production embodiment, which fully conforms to the design goal of large-scale industrial continuous production in the claims. Specifically, it adopts an integrated production line with an annual processing capacity of 100,000 tons. The raw material is hen manure collected centrally from a large-scale breeding park. The initial moisture content of the raw material fluctuates within a daily range of 68% to 75%. The feeding rate, spindle speed of each unit, temperature and residence time are controlled in a coordinated manner through a central control system to ensure that the moisture content of the raw material after pretreatment is always precisely controlled within the range of 70% to 80%. The total processing time for a single batch of material is controlled to 25 minutes. The entire process is a closed and continuous production, with a daily output of approximately 80 tons of modified protein raw materials.

[0027] The test results of 30 days of continuous production in this embodiment show that the modified protein content of the product is stable in the range of 35.0%~35.8% between batches, the non-protein nitrogen content is stable and controlled within 0.3%, pathogenic bacteria, ascarid eggs and antibiotic residues are not detected, the index deviation between batches is ≤1.8%, the overall energy consumption of the system is reduced by 32.6% compared with the traditional external steam hydrolysis process, and the process stability and economy have reached the expected goals.

[0028] Comparative Example 1 This comparative example uses a single drying oven to process the same batch of fresh chicken manure as in Example 1. To ensure the total reaction time, the residence time of the material in the oven is extended to 17 minutes, and the remaining process parameters are the same as in Example 1.

[0029] Testing revealed that the comparative product exhibited a distinct hard shell on its surface, with an internal moisture content as high as 22%, indicating poor drying performance. The modified protein content was only 29.6%, the non-protein nitrogen content was 8.5%, and the antibiotic residue degradation rate was 42.3%, failing to meet feed-grade requirements. Furthermore, localized gelatinization and carbonization of the material were observed, resulting in inconsistent product quality.

[0030] Comparative Example 2 This comparative example uses a single drying oven to process the same batch of fresh chicken manure as in Example 1, maintaining normal drying speed and a 7-minute residence time, with the remaining process parameters being the same as in Example 1.

[0031] Testing revealed that the comparative product could only be used as a raw material for organic fertilizer. The modified protein content was 28.7%, the non-protein nitrogen content was 14.2%, and the antibiotic residue degradation rate was only 38.5%. The harmlessness level was significantly lower than that of the present invention, and it could not be utilized for high value.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention. The present invention can flexibly adjust the process parameters of the two-stage drying according to the characteristics of different livestock and poultry waste raw materials such as pig manure, cow manure, and livestock sludge, all of which are within the protection scope of the present invention.

Claims

1. A method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure, characterized in that, Includes the following steps: Step 1, raw material pretreatment: Fresh livestock and poultry manure is screened to remove impurities, stirred and conditioned to a moisture content of 70%~80%, and then sent to the preheating furnace; the combustion furnace is started to heat the drying furnace, and the hot exhaust gas generated by the drying furnace is sent to the jacket cavity of the preheating furnace after being dusted by a cyclone dust collector. The material is stirred, sheared and pushed in the preheating furnace by the stirring components to achieve low temperature preheating and mechanical cell wall breaking. Step Two, Primary High-Temperature Low-Oxygen Dehydration and Degradation: The preheated material is fed into the first drying oven. An open flame is injected from one end of the first drying oven, with an inlet temperature of 800℃~1100℃. A gradient temperature zone of 800℃ to 400℃ is formed inside the oven along the material's direction of travel. The material is evenly coated onto the high-temperature inner wall of the drying oven by a stirring component with a trowel, completing dehydration. The material's own moisture evaporates in situ, generating a large amount of steam, which is discharged from the oven to create a low-oxygen reaction atmosphere. Under the action of boiling with water, the temperature of the material is stably maintained at 100~110℃ without gelatinization. Under the combined action of the gradient high temperature, self-generated steam, and low oxygen in the oven, preliminary dehydration and the first stage of degradation and modification are completed simultaneously. The material stays in the first drying oven for 7~8 minutes, and the output moisture content is controlled at 35%~45%. Step 3, Secondary High-Temperature Low-Oxygen Deep Dehydration and Degradation: The material dried in the first stage is sent to the second drying furnace through a closed conveyor pipe. An open flame is injected from one end of the second drying furnace, creating a gradient temperature zone of 800℃ to 400℃ along the material's direction of travel. The material is evenly coated onto the high-temperature inner wall of the drying furnace by a stirring component with a trowel, continuing dehydration. The remaining moisture in the material continues to evaporate in situ, generating steam and maintaining a low-oxygen reaction atmosphere inside the furnace. The material temperature remains stable at 100~110℃ without gelatinization. Under the combined effects of the gradient high temperature, self-generated steam, and low oxygen in the furnace, deep dehydration and the second stage of degradation and modification are completed simultaneously. The material remains in the second drying furnace for 8~10 minutes, and the output moisture content is controlled at 8%~13%. Step 4, Waste heat recovery and exhaust gas treatment: The waste heat exhaust gas generated by the first and second drying ovens is cyclone dust collector, part of which is sent to the preheating oven as a preheating heat source, and the other part is recovered by the heat exchanger and then sent to the dust removal spray tower for treatment to meet the emission standards. Step 5, finished product preparation: The material that has undergone two-stage simultaneous dehydration and degradation modification is removed and dried to adjust the moisture content to below 14%. After cooling, the finished product containing modified protein is obtained.

2. The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure according to claim 1, characterized in that, In step one, the fresh livestock and poultry manure is fresh chicken manure from a large-scale farm, and the initial moisture content of the raw material is best at 70%~71%.

3. The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure according to claim 1, characterized in that, The residence time of the material in the cavity section corresponding to the temperature range of 400~600℃ in each drying oven shall not be less than 2.5 minutes, and the total residence time of the two stages shall not be less than 5 minutes.

4. The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure according to claim 1, characterized in that, During the modified protein conversion process in steps two and three, the macromolecular proteins in the material are gradually degraded into small molecule peptides and free amino acids. The non-protein nitrogen of urate in the material completes the heterocyclic ring opening and directional conversion into amino acid nitrogen. The residues of tetracycline, quinolone, and sulfonamide aquaculture drugs are completely degraded.

5. The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure according to claim 1, characterized in that, The high-temperature steam produced in the first and second drying ovens is the sole steam source for the corresponding reaction processes within the ovens, eliminating the need for external steam and water sources throughout the entire process.

6. The method for preparing modified protein raw materials by high-temperature self-generated steam degradation of livestock and poultry manure according to claim 1, characterized in that, By uniformly adjusting the moisture content during the raw material pretreatment stage and controlling the moisture content in stages during two-stage drying, the problems of material surface hardening, difficulty in removing internal moisture, and insufficient steam output caused by prolonged residence time in a single furnace are avoided, thus ensuring the drying effect and the continuous and stable steam supply required for modified protein conversion.

7. A modified protein raw material from livestock and poultry manure, characterized in that, The modified protein raw material is prepared by the method according to any one of claims 1 to 6, wherein the water content is ≤14%, the modified protein content is ≥35%, and the non-protein nitrogen content is ≤0.3%.