Method for preparing artificial peat and fulvic acid from livestock and poultry manure in breeding industry through high-pressure hydrothermal method

Abstract

The invention relates to a method for preparing artificial peat and fulvic acid from livestock and poultry manure in the breeding industry by a high-pressure hydrothermal method, which comprises the following steps: regulating the concentration of the livestock and poultry manure to be 10-40% by using part of flash condensate, pressurizing by using a high-pressure pump, feeding into a tubular hydrothermal reactor and a tower type delay reactor for hydrothermal reaction, and then separating by using a depressurization flash tower to obtain the artificial peat and fulvic acid. After the gas phase enters a preheating heat exchanger to be cooled and liquefied, part of flash evaporation condensate is circulated back to the livestock and poultry manure concentration adjusting tank, and solid-phase slurry is separated through a filter press; filtering to obtain solid serving as artificial peat, pumping filtrate into a tubular heater at high pressure, heating to 380 DEG C or above, and desalting in a desalting tower; and mixing the desalted filtrate with the residual flash condensate to obtain a fulvic acid product.

Description

1. Technical Field

[0001] The invention provides a method for preparing artificial peat and fulvic acid by using livestock and poultry excrement in aquaculture 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, the scale and density of livestock and poultry farming have greatly increased, and the resulting livestock and poultry manure pollution has continued to intensify. Livestock manure contains antibiotics, parasite eggs, pathogenic bacteria, viruses and weed seeds. It also contains a large amount of nitrogen, phosphorus, potassium, and heavy metal elements (copper, zinc, arsenic, etc.) and salt. If it is not treated in time, on the one hand, it will cause serious crop diseases, insect pests and weeds after use in farmland, causing a lot of pollution to land and water resources. On the other hand, it will bring food safety problems and air pollution caused by odor, which has not only become an important factor restricting the sustainable development of animal husbandry and agriculture, but also poses a great challenge to rural environmental governance.

[0003] Returning livestock and poultry manure to the fields is the fundamental way out and a fundamental solution to the problem of livestock and poultry breeding pollution. The existing high-temperature composting or fermentation of livestock and poultry manure to produce organic fertilizer is difficult to kill antibiotics, parasite eggs, pathogenic bacteria, viruses and weed seeds because the temperature does not exceed 80°C, making it difficult to achieve safe, clean and efficient green return to the fields. Livestock and poultry manure contains rich organic matter and nutrients. As a cultivation matrix, it can provide plants with the necessary nutrients, promote plant growth and development, and increase yield and quality. There are a large number of beneficial microorganisms in livestock and poultry manure. By using it as a cultivation matrix, it can provide nutrition and suitable environmental conditions for the cultivation of microorganisms, and be used for the research and development and production of biological preparations or biofertilizers. Therefore, it is urgent to develop production processes and equipment technologies that can transform it into matrix materials suitable for plant or microbial growth, so as to achieve the effective utilization of 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 the existing livestock and poultry manure production organic fertilizer and cultivation substrate technology and to invent a method for preparing artificial peat and fulvic acid from livestock and poultry manure in the aquaculture industry 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 the aquaculture manure, utilizes the property of supercritical water that salt is difficult to dissolve to remove heavy metal elements and salt in the hydrolyzed fulvic acid, eradicates the two major problems of antibiotics and pests and diseases, heavy metals and salt damage that are difficult to solve in the existing livestock and poultry manure production organic fertilizer process, and ensures the safe, clean and efficient disposal and green return of livestock and poultry manure to the field.

[0005] The technical solution of the present invention:

[0006] A method for preparing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method in the breeding industry, wherein the concentration of livestock and poultry manure is adjusted to 10%-40% by using part of the flash condensate, and then the manure is pressurized by a high-pressure feed pump and sent into an electromagnetic pipeline reactor 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 saturated pressure of water at the reaction temperature, and the reaction time is 1-90 seconds; and then the manure is sent into a tower delay reactor to extend the reaction time by 10-50 minutes to further strengthen 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 circulated back to the livestock and poultry manure concentration tank, and 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 into a tubular heater again by a high-pressure pump to heat it to above 380°C and then desalted in a supercritical settler, and the salt is separated from the desalting tank, and the filtrate is mixed with the remaining part of the flash condensate as 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 generates an alternating magnetic field through the coil, 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 is described in detail with reference to embodiments. 4. Description of the drawings

[0012] Attached Figure 1 It is a schematic diagram of the present invention.

[0013] Attached 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 regulator 6. Tower delayed reactor 7. Pressure-reducing flash tower 8. Filter press 9. Tubular heater 10. Supercritical settler 11. Desalting 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 in conjunction with the accompanying drawings and embodiments. 5. Specific implementation methods

[0016] Embodiment, a method for preparing artificial peat and fulvic acid from livestock and poultry manure by high-pressure hydrothermal method in the breeding industry, wherein the concentration of livestock and poultry manure added from the livestock and poultry manure inlet A in the livestock and poultry manure concentration tank (2) is adjusted to 10%-40%, and then the liquid is pressurized by a high-pressure feed pump (1) and sent to 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 saturated pressure of water at the reaction temperature, and the reaction time is 1-90 seconds; and then the liquid is sent to 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 phase 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 increase the temperature to above 380°C and then desalted in a supercritical sedimentator (10); the salt is separated from the desalting tank (11), and the filtrate is mixed with the remaining part of the flash condensate to obtain a fulvic acid product after the waste heat is recovered.

[0017] The electromagnetic heating tubular reactor (4) is a tubular reactor in which, under the action of the electromagnetic heating controller (5), high-frequency alternating current generates an alternating magnetic field through the coil, 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.

[0018] The tower 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 flashing high-temperature steam to cool and liquefy it 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 reacted 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 to be heated to 380°C for desalination, and the yield of artificial peat with a brown and black humic acid content of 46.5% is 15%, and the rest is fulvic acid with a concentration of 21%. The products do not contain antibiotics, parasite eggs, pathogenic bacteria, viruses, weed seeds, heavy metal elements and salts.

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

Claims

1. A method for preparing 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, it is pressurized and sent to an electromagnetic pipeline reactor through a high-pressure feed pump 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 not lower than the saturated pressure of water at the reaction temperature, and the reaction time is 1-90 seconds; it is then sent to a tower delay reactor to extend the reaction time for 10-50 minutes to further strengthen the hydrothermal decomposition reaction; then the hydrothermal reaction slurry at the bottom of the tower delay reactor is separated into gas and solid 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, and the solid phase slurry is separated by a filter press; the solid is filtered to obtain a solid as an artificial peat product, and the filtrate is sent to a tubular heater again by a high-pressure pump, and after the temperature is raised to above 380°C, it is desalted in a supercritical settler, and the salt is separated from the desalting tank, and the filtrate is mixed with the remaining part of the flash condensate as a fulvic acid product after recovering the waste heat.

2. The method for preparing 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 tubular reactor in which, under the action of an electromagnetic heating controller, high-frequency alternating current passes through a coil to generate an alternating magnetic field, and eddy current self-heating is generated on the tubular reactor wall and the internal self-mixing strengthening internal components. The self-mixing strengthening internal components are regular packing type, X-cross plate type or spiral plate type.

3. The method for preparing 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 preparing 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 preparing 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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