Method for producing artificial peat and fulvic acid by high-pressure hydrothermal method from livestock and poultry manure

Abstract

A method for producing artificial peat and fulvic acid from livestock and poultry manure using a high-pressure hydrothermal method. The method comprises: using part of the flash condensate to adjust the concentration of the livestock and poultry manure to 10%-40%, the manure is then pressurized by a high-pressure pump and fed into a tubular hydrothermal reactor and a tower-type delayed reactor for hydrothermal reaction. The manure is then separated by a pressure-reducing flash tower. The gas phase enters a preheating heat exchanger for cooling and liquefaction, and part of the flash condensate is circulated back to the livestock and poultry manure concentration tank. The solid slurry is separated by a filter press. The solid is filtered to obtain artificial peat, and the filtrate is pumped to a tubular heater at high pressure to raise the temperature to above 380°C, and then desalted in a desalting tower. The desalted filtrate and the remaining flash condensate are mixed to produce the fulvic acid product.

Description

1. Technical Field

[0001] The invention provides a method for preparing artificial peat and fulvic acid from livestock and poultry manure in the breeding industry using a high-pressure hydrothermal method, and relates to the field of chemical industry. 2. Background Technology

[0002] With the rapid development of my country's animal husbandry industry, the scale and density of livestock and poultry farming have greatly increased, and the resulting environmental pollution caused by livestock and poultry manure has continued to intensify. Livestock manure contains antibiotics, parasite eggs, pathogenic bacteria, viruses, and weed seeds. It also contains large amounts of nitrogen, phosphorus, and potassium, as well as heavy metals (copper, zinc, arsenic, etc.) and salt. If not promptly treated, its use in farmland can lead to serious crop pests and diseases, causing extensive pollution to land and water resources. Furthermore, it poses food safety risks and atmospheric pollution caused by foul odors. This has become a major constraint on the sustainable development of animal husbandry and agriculture, and poses a significant challenge to rural environmental governance.

[0003] Returning livestock and poultry manure to farmland for utilization is a fundamental solution to the problem of livestock and poultry breeding pollution and a fundamental solution. Currently, livestock and poultry manure is composted or fermented at high temperatures to produce organic fertilizer. However, because the temperature does not exceed 80°C, it is difficult to kill antibiotics, parasite eggs, pathogenic bacteria, viruses, and weed seeds, making it difficult to achieve safe, clean, and efficient green return to the fields. Livestock and poultry manure is rich in organic matter and nutrients. As a cultivation medium, it can provide plants with the nutrients they need, promote plant growth and development, and increase yield and quality. Livestock and poultry manure contains a large number of beneficial microorganisms. By using it as a cultivation medium, it can provide nutrition and suitable environmental conditions for the cultivation of microorganisms, and can be used for the research and development and production of biological agents or biofertilizers. Therefore, there is an urgent need to develop production processes and equipment technologies to convert it into a matrix material suitable for plant or microbial growth, so as to achieve the effective utilization of the organic matter and nutrients in livestock and poultry manure. 3. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of existing livestock and poultry manure production organic fertilizer and cultivation substrate technology and to invent a method for producing artificial peat and fulvic acid from livestock and poultry manure by a high-pressure hydrothermal method. The method utilizes high-temperature and high-pressure hydrothermal decomposition and killing of antibiotics, parasite eggs, pathogenic bacteria, viruses and weed seeds in livestock and poultry manure, and utilizes the property of supercritical water that is difficult to dissolve salt to remove heavy metal elements and salt in the hydrolyzed fulvic acid. The method eradicates the two major problems of antibiotics and pests and diseases, and heavy metals and salt damage that are difficult to solve in the existing livestock and poultry manure production organic fertilizer process, thereby ensuring the safe, clean and efficient disposal and green return of livestock and poultry manure to farmland.

[0005] The technical solution of the present invention:

[0006] A method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method in the livestock and poultry farming industry comprises the following steps: using part of the flash condensate to adjust the concentration of the livestock and poultry manure to 10%-40%, and then pressurizing the manure into an electromagnetic pipeline reactor through a high-pressure feed pump for hydrothermal decomposition reaction, wherein the flow rate in the pipe is 1-5 m / s, the reaction temperature is 200-330°C, the pressure is ≥ the saturated pressure of water at the reaction temperature, and the reaction time is 1-90 seconds; the manure is then sent to a tower-type delayed reactor to extend the reaction time by 10-50 minutes to further intensify the hydrothermal reaction. Decomposition reaction; then the hydrothermal reaction slurry at the bottom of the tower delayed reactor is separated into gas and solid by a pressure-reducing flash tower. The gas phase enters the preheating heat exchanger for cooling and liquefaction, and part of the flash condensate is recycled back to the livestock and poultry manure concentration tank. The solid phase slurry is separated by a filter press; the solid is filtered to obtain an artificial peat product, and the filtrate is pumped back into a tubular heater by a high-pressure pump to raise the temperature to above 380°C, and then desalted in a supercritical settler. The salt is separated from the desalting tank, and the filtrate is mixed with the remaining flash condensate to obtain a fulvic acid product after recovering the waste heat.

[0007] Among them, the electromagnetic heating tubular reactor is a tubular reactor in which, under the action of the electromagnetic heating controller, high-frequency alternating current passes through the coil to generate an alternating magnetic field, and the tubular reactor wall and the internal self-mixing strengthening internal components generate eddy current self-heating, thereby achieving uniform heating, rapid temperature rise and hydrothermal reaction of the high-pressure alkaline slurry; the self-mixing strengthening internal components are regular packing type, X-cross plate type or spiral plate type.

[0008] The tower delayed reactor has a height-to-diameter ratio of 3-30:1, and has filler components, grid self-mixing components or an empty tower inside.

[0009] The pressure-reducing flash tower is set to 1-2 stages, and the heat exchanger for cooling and liquefying the flash high-temperature steam is a coil heat exchanger.

[0010] The bottom of the supercritical settler is connected to two or more desalting tanks through a cut-off valve.

[0011] The present invention will be described in detail with reference to embodiments. 4. Description of the Figures

[0012] Attachment Figure 1 Schematic diagram of the present invention.

[0013] Attachment Figure 1 The following is a description of the drawings:

[0014] 1. High-pressure feed pump 2. Livestock and poultry manure concentration tank 3. Heat exchanger 4. Electromagnetic heating tubular reactor 5. Electromagnetic heating controller 6. Tower delayed reactor 7. Pressure-reducing flash tower 8. Filter press 9. Tubular heater 10. Supercritical settler 11. Desalination tank A, Livestock and poultry manure inlet B, Artificial peat outlet C, Fulvic acid outlet

[0015] The process characteristics of the present invention are described in detail below with reference to the accompanying drawings and embodiments. 5. Specific implementation methods

[0016] In an embodiment, a method for producing artificial peat and fulvic acid from livestock and poultry manure by a high-pressure hydrothermal method is provided. Part of the flash condensate obtained by a heat exchanger (3) is added to the livestock and poultry manure concentration tank (2) from the livestock and poultry manure inlet A to adjust the concentration to 10%-40%. The liquid is then pressurized by a high-pressure feed pump (1) and fed into an electromagnetic pipeline reactor (4) for hydrothermal decomposition reaction, wherein the flow rate in the tube is 1-5 m / s, the reaction temperature is 200-330°C, the pressure is ≥ the saturation pressure of water at the reaction temperature, and the reaction time is 1-90 seconds; the liquid is then fed into a tower delay reactor (6) to extend the reaction time by 10-5 0 minutes to further strengthen the hydrothermal decomposition reaction; then the hydrothermal reaction slurry at the bottom of the tower delayed reactor (6) is separated into gas and solid by a pressure-reducing flash tower (7); the gas phase enters the heat exchanger (3) for cooling and liquefaction, and part of the flash condensate is circulated back to the livestock and poultry manure concentration tank (2); the solid slurry is separated by a filter press (8); the solid is filtered to obtain an artificial peat product, and the filtrate is pumped into the tubular heater (9) again to be heated to above 380°C and then desalted in a supercritical sedimentator (10), and the salt is separated from the desalting tank (11). The filtrate is mixed with the remaining flash condensate to obtain a fulvic acid product after recovering the waste heat.

[0017] The electromagnetic heating tubular reactor (4) is configured such that when a high-frequency alternating current is passed through a coil to generate an alternating magnetic field under the action of an electromagnetic heating controller (5), the tubular reactor wall and the self-mixing strengthening internal components therein generate eddy current self-heating, thereby achieving uniform heating, rapid temperature rise, and hydrothermal reaction of the high-pressure alkaline slurry; and the self-mixing strengthening internal components are of a structured packing type, an X-cross plate type, or a spiral plate type.

[0018] The tower-type delayed reactor (6) has a height-to-diameter ratio of 3-30:1, and has a filler component, a grid self-mixing component or an empty tower inside.

[0019] The pressure-reducing flash tower (7) is set to 1-2 stages, and the heat exchanger (3) for cooling and liquefying the flash high-temperature steam is a coil-type heat exchanger.

[0020] The bottom of the supercritical settler (10) is connected to two or more desalting tanks (11) via a cut-off valve.

[0021] The specific reaction conditions and experimental results are as follows: a 30wt% livestock and poultry manure solution is hydrothermally reacted in an electromagnetic pipeline reactor at a flow rate of 2 m / s, a temperature of 280°C, and a pressure of 2.7 MPa for 10 seconds, and then delayed in a tower delayed reactor for 50 minutes; the filtrate is again sent into a tubular heater and a supercritical settler by a high-pressure pump and heated to 380°C for desalination. The yield of artificial peat with a brownish-black humic acid content of 46.5% is 15%, and the rest is fulvic acid with a concentration of 21%. The product does not contain antibiotics, parasite eggs, pathogenic bacteria, viruses, weed seeds, heavy metal elements, and salts.

[0022] The present invention provides a method for producing artificial peat and fulvic acid from livestock and poultry manure using a high-pressure hydrothermal method. The method comprises: performing electromagnetic heating pipeline high-pressure hydrothermal decomposition, enhancing hydrothermal decomposition and killing antibiotics, parasite eggs, pathogenic bacteria, viruses and weed seeds in the livestock manure in a tower-type delayed reactor, followed by flash separation; and then utilizing the property of supercritical water that it is difficult to dissolve salts to remove heavy metal elements and salt from the hydrothermally decomposed fulvic acid. The method obtains an artificial peat yield of more than 48% (dry basis yield) with the same properties as natural peat and fulvic acid with a pH value of 3-4. The electromagnetic heating energy consumption is reduced by 30%, thereby eradicating the two major problems of antibiotics and pests, diseases, insects and weeds, and heavy metals and salt damage, which are difficult to solve in the existing livestock and poultry manure production process for organic fertilizer, thereby ensuring the safe, clean and efficient disposal and green return of livestock and poultry manure to farmland.

Claims

1. A method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method, characterized in that After the concentration of livestock and poultry manure is adjusted to 10%-40% by using part of the flash condensate, the manure is pressurized and fed into an electromagnetic pipeline reactor by a high-pressure feed pump for hydrothermal decomposition reaction, wherein the flow velocity in the pipeline is 1-5 m / s, the reaction temperature is 200-330°C, the pressure is not less than the saturation pressure of water at the reaction temperature, and the reaction time is 1-90 seconds. The manure is then fed into a tower-type delayed reactor to extend the reaction time by 10-50 minutes to further strengthen the hydrothermal decomposition reaction. The hydrothermal reaction slurry at the bottom of the tower-type delayed reactor is then subjected to gas-solid separation by a pressure-reducing flash tower. The gas phase enters a preheating heat exchanger for cooling and liquefaction, and part of the flash condensate is circulated back to the livestock and poultry manure concentration tank. The solid phase slurry is separated by a filter press. The solid is filtered to obtain an artificial peat product. The filtrate is fed into a tubular heater again by a high-pressure pump, heated to above 380°C, desalted in a supercritical sedimentator, and the salt is separated from the desalting tank. The filtrate is mixed with the remaining flash condensate to obtain a fulvic acid product after waste heat recovery.

2. The method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method according to claim 1, characterized in that The electromagnetic heating tubular reactor is a reactor in which high-frequency alternating current generates an alternating magnetic field through a coil under the action of an electromagnetic heating controller, and the tubular reactor wall and the internal self-mixing strengthening internal components generate eddy current self-heating. The self-mixing strengthening internal components are structured packing type, X-cross plate type or spiral plate type.

3. The method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method according to claim 1, characterized in that The tower delayed reactor has a height-to-diameter ratio of 3-30:1, and has filler components, grid self-mixing components or an empty tower inside.

4. The method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method according to claim 1, characterized in that The pressure-reducing flash tower is set to 1-2 stages, and the heat exchanger for cooling and liquefying the flash high-temperature steam is a coil heat exchanger.

5. The method for producing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method according to claim 1, characterized in that The bottom of the supercritical settler is connected to two or more desalting tanks through a cut-off valve.

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