Method for producing fulvic acid by pyrolysis and pilot plant

Abstract

The application discloses a method and a pilot plant device for producing fulvic acid by pyrogenation, and the device comprises a heat conducting oil boiler, a grinder, a reaction kettle, a jacketed cooler, a buffer tank, a circulating cooling tower and a circulating cooling water pump, wherein the heat conducting oil boiler is connected with the reaction kettle in circulation, the grinder is connected with the reaction kettle and the buffer tank in sequence, the jacketed cooler is arranged on a pipeline between the reaction kettle and the buffer tank, the jacketed cooler is further connected with the circulating cooling tower, the circulating cooling water pump and the buffer tank in sequence, and the buffer tank is further connected with the jacketed cooler and the circulating cooling tower respectively.

Description

Technical Field

[0001] This invention relates to the field of waste treatment technology, and more specifically to a method and pilot-scale apparatus for producing humic acid by pyrolysis. Background Technology

[0002] Wet waste refers to the waste generated in daily life, food processing, catering services, and institutional catering. It is characterized by high water content and high organic matter content, making it easy to decompose and produce foul odors, posing a threat to the urban living environment and residents' health.

[0003] Based on the differences in collection systems and waste composition characteristics at actual treatment plants, wet waste is divided into two main categories: kitchen waste and food waste.

[0004] Kitchen waste refers to kitchen scraps and fruit peels generated in residential areas and farmers' markets after sorting.

[0005] Food waste refers to food scraps and food processing waste generated from activities such as food processing, catering services, and catering services provided by institutions, which are outside of residents' daily lives.

[0006] The complexity of the composition of wet waste means that using a single existing treatment technology is insufficient for efficient and high-value processing and utilization. Therefore, separating the components of wet waste and comprehensively applying multiple treatment and utilization technologies is one development strategy.

[0007] With the continuous improvement of wet waste resource utilization technology and the increasing perfection of management regulations, we should continue to carry out various technology integration practices and innovations around wet waste treatment in the future, so as to ultimately achieve the goal of efficient resource utilization and harmless treatment of wet waste.

[0008] Therefore, how to provide a simple and efficient method for treating wet waste is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] In view of this, the present invention provides a method and pilot-scale apparatus for producing humic acid by pyrolysis of wet waste as raw material.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A pilot-scale apparatus for producing fulvic acid by pyrolysis includes: a thermal oil boiler, a grinding mill, a reaction vessel, a shell-and-tube cooler, a buffer tank, a circulating cooling tower, and a circulating cooling water pump;

[0012] The thermal oil boiler is circulated and connected to the reaction vessel.

[0013] The grinding mill is connected in sequence to the reaction vessel and the buffer tank;

[0014] The sleeve cooler is installed on the pipeline between the reactor and the buffer tank;

[0015] The shell-and-tube cooler is also connected in sequence to the circulating cooling tower, the circulating cooling water pump, and the buffer tank.

[0016] The buffer tank is also connected to the shell-and-tube cooler and the circulating cooling tower, respectively.

[0017] Preferably, a first regulating valve and a second regulating valve are respectively installed on the two pipelines connecting the thermal oil boiler and the reactor.

[0018] Preferably, a bypass is provided between the thermal oil boiler and the first regulating valve, and between the thermal oil boiler and the second regulating valve, and a third regulating valve is provided on the bypass.

[0019] Preferably, a first control valve is provided between the grinder and the reaction vessel; a second control valve is provided at the bottom of the reaction vessel.

[0020] Preferably, a third control valve, a fourth regulating valve, and a fourth control valve are sequentially arranged between the reactor and the shell cooler.

[0021] Preferably, a sixth control valve is provided between the circulating cooling water pump and the buffer tank; a fifth control valve is provided at the bottom of the buffer tank.

[0022] Preferably, the reactor is provided with a jacket, and the jacket is provided with a heat transfer oil inlet and a heat transfer oil outlet; the heat transfer oil inlet is connected to the first regulating valve; the heat transfer oil outlet is connected to the second regulating valve.

[0023] Temperature and pressure sensors are installed at the outlets of the thermal oil boiler, reaction vessel, circulating cooling water pump, and buffer tank.

[0024] Preferably, the pilot plant also includes a matching electrical cabinet and a PLC control system.

[0025] A method for producing fulvic acid by pyrolysis, characterized in that the pilot-scale apparatus for producing fulvic acid by the above-mentioned pyrolysis method specifically includes the following steps:

[0026] S1 Preprocessing

[0027] Leftover food, fruit peels, and vegetable leaves are poured into the feed inlet of the grinder and ground into fine particles. At the same time, water is added to adjust the slurry to a solids content of 5% to 30%. The grinder is frequency-controlled, and by adjusting the grinding frequency (0 to 50 Hz), the particle size of the organic slurry (0.1 to 3 mm) can be controlled according to specific process requirements.

[0028] S2 hydrothermal degradation conversion

[0029] Add dipotassium hydrogen phosphate to the slurry obtained above and send the slurry into the reactor. Control the temperature of the reactor by using a thermal oil boiler so that the material in the reactor undergoes anaerobic reaction, dehydration polymerization reaction and aromatic cyclization reaction in sequence to obtain high value-added humic acid.

[0030] S3 Cooling and Discharge

[0031] After most of the liquid in the reactor is cooled naturally, it is discharged from the reactor outlet. The generated flash vapor enters the buffer tank through the third control valve, the fourth regulating valve, the fourth control valve, and the shell cooler to cool and depressurize, forming liquid organic fertilizer products.

[0032] Preferably, in step S2, the mass ratio of the propeller to the dipotassium hydrogen phosphate is (1:1000) to (1:100);

[0033] The anaerobic reaction temperature is 10–70℃, the time is 10–30 min, and the pressure is <0.04 MPa. The easily degradable organic matter in the slurry mainly undergoes hydrolysis, and the macromolecular organic matter is decomposed into small molecules. For example, cellulose is decomposed into cellobiose and glucose, starch is decomposed into maltose and glucose, and protein is decomposed into short peptides and amino acids.

[0034] The dehydration polymerization reaction is carried out at a temperature of 80–140°C for 30–80 min and a pressure of 0.04–0.37 MPa. The intermediate product undergoes further chemical reactions, forming more stable macromolecules through dehydration and polymerization.

[0035] The aromatic cyclization reaction is carried out at a pressure of 1–1.6 MPa, a temperature of 180°C–200°C, and a time of 20–100 min. Macromolecular organic matter is transformed into aromatic compounds through a series of dehydration and deformaldehyde removal processes. These compounds then condense with nitrogen-containing compounds, hydrolyzed sugars (including monosaccharides, polysaccharides, etc.), and organic acids (furfural, amino acids, etc.) to form humus, which has high resource utilization value.

[0036] Preferably, in step S2, when the thermal oil boiler heats the material in the reactor, the first and second regulating valves are opened, and the third regulating valve is closed. When the heated thermal oil flows through the jacket, it transfers heat to the reactor, thereby heating the material inside. When the desired reaction temperature is reached, the flow rate of the thermal oil in the internal and external circulation channels can be controlled by adjusting the opening of the three regulating valves to achieve precise temperature control.

[0037] Preferably, in step S3, the high-value-added humic acid enters the buffer tank through a pipeline equipped with three valves, namely the third control valve, the fourth regulating valve, and the fourth control valve. During cooling, the flow rate of flash vapor entering the buffer tank is adjusted by controlling the valve degree of the regulating valve. The two switching valves ensure the airtightness of the pipeline.

[0038] When the third control valve, the fourth regulating valve, and the fourth control valve are opened, the liquid in the reactor will suddenly depressurize and rapidly vaporize to form flash steam. At this time, the flash steam has a high temperature and pressure. Since the pipeline from the reactor to the buffer tank is equipped with a jacket cooler, the flash steam cools down rapidly as it passes through the pipeline.

[0039] The buffer tank is equipped with a jacket, through which circulating cooling water is introduced. When flash steam is introduced into the buffer tank, it can further reduce the temperature and pressure, and at the same time, it forms liquid organic fertilizer products upon cooling.

[0040] Preferably, circulating cooling water is provided to the shell-and-tube cooler and the jacket via a circulating cooling tower and a circulating cooling water pump.

[0041] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. Wet waste treated by hydrothermal processes has a high degree of humification, with a large portion of the organic matter being converted into humic acid. More than two-fifths of the organic matter exists in the form of humic acid. Reducing organic matter loss and carbon emissions helps to conserve energy and reduce carbon emissions, thus promoting sustainable development.

[0043] 2. This device can also be controlled by a PLC, allowing for precise control of the temperature and time required for the organic reaction by setting three temperature ranges and changing parameters. Combined with intelligent algorithm logic, it achieves automated control of on-site equipment, reducing energy consumption and improving efficiency. Remote monitoring is supported on mobile phones and computers, allowing for convenient real-time monitoring of the system status. The remote monitoring function enables users to view real-time data, alarm information, and historical records at any time, improving work efficiency.

[0044] 3. Utilizing a specialized catalyst improves product conversion and yield. During the reaction, dipotassium hydrogen phosphate undergoes a decomposition reaction promoted by hydrogen ions from water self-ionization, followed by a condensation reaction with macromolecular aromatic compounds to form humic acid. This is because in the initial hydrothermal phase, strong hydrolysis reactions, primarily acetic acid hydrolysis and degradation, occur. The hydrogen ions provided by dipotassium hydrogen phosphate during this period accelerate and intensify the hydrolysis reaction, thus promoting humic substance formation. This improves reaction efficiency, catalyst utilization, and product quality.

[0045] 4. By controlling the temperature field, pressure field, flow field, heating time, and residence time of materials in the aromatic cyclization reaction, the carbon elements in the organic matter are controlled in the reaction product fulvic acid, thereby achieving the goal of energy conservation and carbon reduction. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0047] Figure 1 This is a structural diagram of the device of the present invention;

[0048] Figure 2 This is a structural diagram of the reaction vessel of the present invention;

[0049] In the figure:

[0050] 1-Heat transfer oil boiler; 2-Reaction vessel; 3-Grinding machine; 4-Shell-tube cooler; 5-Buffer tank; 6-Circulating cooling tower; 7-Circulating cooling water pump; 11-First regulating valve; 12-Second regulating valve; 13-Third regulating valve; 14-Fourth regulating valve; 21-First control valve; 22-Second control valve; 23-Third control valve; 24-Fourth control valve; 25-Fifth control valve; 26-Sixth control valve. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some 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.

[0052] Example 1

[0053] This embodiment provides a pilot plant for the pyrolysis production of fulvic acid, including: a thermal oil boiler 1, a grinding mill 3, a reaction vessel 2, a shell-and-tube cooler 4, a buffer tank 5, a circulating cooling tower 6, and a circulating cooling water pump 7.

[0054] Among them, the thermal oil boiler 1 is circulatedly connected to the reaction vessel 2;

[0055] The grinder 3 is connected in sequence to the reactor 2 and the buffer tank 5;

[0056] The shell-and-tube cooler 4 is installed on the pipeline between the reactor 2 and the buffer tank 5;

[0057] The shell-and-tube cooler 4 is also connected in sequence to the circulating cooling tower 6, the circulating cooling water pump 7, and the buffer tank 5;

[0058] The buffer tank 5 is also connected to the shell-and-tube cooler 4 and the circulating cooling tower 6.

[0059] In this embodiment, a first regulating valve 11 and a second regulating valve 12 are respectively installed on the two pipelines connecting the thermal oil boiler 1 and the reactor 2.

[0060] A bypass is provided between the thermal oil boiler 1 and the first regulating valve 11, and between the thermal oil boiler 1 and the second regulating valve 12. A third regulating valve 13 is provided on the bypass.

[0061] A first control valve 21 is provided between the grinder 3 and the reactor 2; a second control valve 22 is provided at the bottom of the reactor 2.

[0062] A third control valve 23, a fourth regulating valve 14, and a fourth control valve 24 are sequentially installed between the reactor 2 and the shell cooler 4.

[0063] A sixth control valve 26 is installed between the circulating cooling water pump 7 and the buffer tank 5; a fifth control valve 25 is installed at the bottom of the buffer tank 5.

[0064] The reactor 2 is equipped with a jacket, which has a heat transfer oil inlet and a heat transfer oil outlet; the heat transfer oil inlet is connected to the first regulating valve 11; the heat transfer oil outlet is connected to the second regulating valve 12.

[0065] Temperature and pressure sensors are installed at the outlets of the thermal oil boiler 1, the reactor 2, the circulating cooling water pump 7, and the buffer tank 5.

[0066] To further optimize the above technical solution, the pilot plant also includes a supporting electrical cabinet and PLC control system.

[0067] The PLC control system in this embodiment implements automated control and is equipped with "one-button start" and "one-button stop" functions. The equipment can be remotely monitored via a mobile device, achieving 24-hour unattended monitoring and intelligent equipment control. These are all conventional methods in the prior art and will not be elaborated further.

[0068] Example 2

[0069] This embodiment provides a method for producing fulvic acid by pyrolysis. The pilot-scale apparatus for producing fulvic acid by pyrolysis described above specifically includes the following steps:

[0070] S1 Preprocessing

[0071] Leftover food, fruit peels and vegetable leaves are poured into the feed inlet of grinder 3 and ground and refined by grinder 3. At the same time, water is added to adjust the slurry to a solid content of 20%. Grinder 3 is frequency-controlled. By adjusting the grinding frequency (40Hz), the particle size of the organic slurry can be controlled to be less than (3mm) according to specific process requirements.

[0072] S2 hydrothermal degradation conversion

[0073] Potassium hydrogen phosphate catalyst is added to the slurry obtained above, with a catalyst-to-material ratio of 1:1000. The prepared organic slurry is manually added to reactor 2. The reactor temperature is controlled by thermal oil boiler 1, so that the material in reactor 2 undergoes anaerobic reaction, dehydration polymerization reaction, and aromatic cyclization reaction in sequence to obtain high-value-added humic acid. When the thermal oil boiler heats the material in the reactor, the first regulating valve 11 and the second regulating valve 12 are opened, and the third regulating valve 13 is closed. When the heated thermal oil flows through the jacket, it transfers heat to reactor 2, thereby heating the material in the reactor. When the required reaction temperature is reached, the flow rate of thermal oil in the internal and external circulation channels can be controlled by adjusting the opening of the three regulating valves to achieve precise temperature control.

[0074] The anaerobic reaction temperature is 10–70℃, the time is 30 min, and the pressure is <0.04 MPa. The easily degradable organic matter in the slurry mainly undergoes hydrolysis, and the macromolecular organic matter is decomposed into small molecules. For example, cellulose is decomposed into cellobiose and glucose, starch is decomposed into maltose and glucose, and protein is decomposed into short peptides and amino acids.

[0075] The dehydration polymerization reaction is carried out at a temperature of 80–140°C for 80 min at a pressure of <0.37 MPa. The intermediate products undergo further chemical reactions, forming more stable macromolecules through dehydration and polymerization.

[0076] The cyclization reaction is carried out at a pressure of 1.6 MPa, a temperature of 200℃, and a time of 60 min. The macromolecular organic matter is transformed into aromatic compounds through a series of dehydration and deformaldehyde removal processes. Then, it is condensed with nitrogen-containing compounds, hydrolyzed sugars (including monosaccharides, polysaccharides, etc.) and organic acids (furfural, amino acids, etc.) to form humic acid, which has high resource utilization value.

[0077] S3 Cooling and Discharge

[0078] After most of the liquid in reactor 2 is cooled naturally, it is discharged from the outlet of reactor 2. The filter residue is removed to obtain liquid humic acid product. The generated flash vapor enters buffer tank 5 through the third control valve 23, the fourth regulating valve 14, the fourth control valve 24 and the shell cooler 4 to cool and depressurize, forming liquid humic acid product.

[0079] The outer jacket of the buffer tank 4 is circulated with cooling water. When flash steam enters the buffer tank 4, it can be further cooled and at the same time, liquid humic acid products are formed when it is cooled.

[0080] Circulating cooling water is supplied to the shell-and-tube cooler 4 and the jacket via circulating cooling tower 6 and circulating cooling water pump 7.

[0081] Example 3

[0082] This embodiment provides a method for producing fulvic acid by pyrolysis. The pilot-scale apparatus for producing fulvic acid by pyrolysis described above specifically includes the following steps:

[0083] S1 Preprocessing

[0084] Leftover food, fruit peels and vegetable leaves are poured into the feed inlet of grinder 3 and ground and refined by grinder 3. At the same time, water is added to adjust the slurry to a solid content of 20%. Grinder 3 is frequency-controlled. By adjusting the grinding frequency (40Hz), the particle size of the organic slurry can be controlled to be less than (3mm) according to specific process requirements.

[0085] S2 hydrothermal degradation conversion

[0086] Potassium hydrogen phosphate catalyst is added to the slurry obtained above, with a catalyst-to-material ratio of 1:100. The prepared organic slurry is manually added to reactor 2. The reactor temperature is controlled by thermal oil boiler 1, so that the material in reactor 2 undergoes anaerobic reaction, dehydration polymerization reaction, and aromatic cyclization reaction in sequence to obtain high-value-added humic acid. When the thermal oil boiler heats the material in the reactor, the first regulating valve 11 and the second regulating valve 12 are opened, and the third regulating valve 13 is closed. When the heated thermal oil flows through the jacket, it transfers heat to reactor 2, thereby heating the material in the reactor. When the required reaction temperature is reached, the flow rate of thermal oil in the internal and external circulation channels can be controlled by adjusting the opening of the three regulating valves to achieve precise temperature control.

[0087] The anaerobic reaction temperature is 10–70℃, the time is 30 min, and the pressure is <0.04 MPa. The easily degradable organic matter in the slurry mainly undergoes hydrolysis, and the macromolecular organic matter is decomposed into small molecules. For example, cellulose is decomposed into cellobiose and glucose, starch is decomposed into maltose and glucose, and protein is decomposed into short peptides and amino acids.

[0088] The dehydration polymerization reaction is carried out at a temperature of 80–140°C for 30 min at a pressure of <0.37 MPa. The intermediate products undergo further chemical reactions, forming more stable macromolecules through dehydration and polymerization.

[0089] The cyclization reaction is carried out at a pressure of 1.4 MPa, a temperature of 195℃, and a time of 50 min. The macromolecular organic matter is transformed into aromatic compounds through a series of dehydration and deformaldehyde removal processes. Then, it is condensed with nitrogen-containing compounds, hydrolyzed sugars (including monosaccharides, polysaccharides, etc.) and organic acids (furfural, amino acids, etc.) to form humic acid, which has high resource utilization value.

[0090] S3 Cooling and Discharge

[0091] After most of the liquid in reactor 2 is cooled naturally, it is discharged from the outlet of reactor 2. The filter residue is removed to obtain liquid humic acid product. The generated flash vapor enters buffer tank 5 through the third control valve 23, the fourth regulating valve 14, the fourth control valve 24 and the shell cooler 4 to cool and depressurize, forming liquid humic acid product.

[0092] The outer jacket of the buffer tank 4 is circulated with cooling water. When flash steam enters the buffer tank 4, it can further reduce the temperature and pressure, and at the same time, it forms liquid humic acid products when it is cooled.

[0093] Circulating cooling water is supplied to the shell-and-tube cooler 4 and the jacket via circulating cooling tower 6 and circulating cooling water pump 7.

[0094] Example 4

[0095] This embodiment provides a method for producing fulvic acid by pyrolysis. The pilot-scale apparatus for producing fulvic acid by pyrolysis described above specifically includes the following steps:

[0096] S1 Preprocessing

[0097] Leftover food, fruit peels and vegetable leaves are poured into the feed inlet of grinder 3 and ground and refined by grinder 3. At the same time, water is added to adjust the slurry to a solid content of 20%. Grinder 3 is frequency-controlled. By adjusting the grinding frequency (40Hz), the particle size of the organic slurry can be controlled to be less than (3mm) according to specific process requirements.

[0098] S2 hydrothermal degradation conversion

[0099] Potassium hydrogen phosphate catalyst is added to the slurry obtained above, with a catalyst-to-material ratio of 1:200. The prepared organic slurry is manually added to reactor 2. The reactor temperature is controlled by thermal oil boiler 1, so that the material in reactor 2 undergoes anaerobic reaction, dehydration polymerization reaction, and aromatic cyclization reaction in sequence to obtain high-value-added humic acid. When the thermal oil boiler heats the material in the reactor, the first regulating valve 11 and the second regulating valve 12 are opened, and the third regulating valve 13 is closed. When the heated thermal oil flows through the jacket, it transfers heat to reactor 2, thereby heating the material in the reactor. When the required reaction temperature is reached, the flow rate of thermal oil in the internal and external circulation channels can be controlled by adjusting the opening of the three regulating valves to achieve precise temperature control.

[0100] The anaerobic reaction temperature is 10–70℃, the time is 20 min, and the pressure is <0.04 MPa. The easily degradable organic matter in the slurry mainly undergoes hydrolysis, and the macromolecular organic matter is decomposed into small molecules. For example, cellulose is decomposed into cellobiose and glucose, starch is decomposed into maltose and glucose, and protein is decomposed into short peptides and amino acids.

[0101] The dehydration polymerization reaction is carried out at a temperature of 80–140°C for 30 min at a pressure of <0.37 MPa. The intermediate products undergo further chemical reactions, forming more stable macromolecules through dehydration and polymerization.

[0102] The cyclization reaction is carried out at a pressure of 1.3 MPa, a temperature of 190℃, and a reaction time of 60 min. The macromolecular organic matter is transformed into aromatic compounds through a series of dehydration and deformaldehyde removal processes. Then, it is condensed with nitrogen-containing compounds, hydrolyzed sugars (including monosaccharides, polysaccharides, etc.) and organic acids (furfural, amino acids, etc.) to form humic acid, which has high resource utilization value.

[0103] S3 Cooling and Discharge

[0104] After most of the liquid in reactor 2 is cooled naturally, it is discharged from the outlet of reactor 2. The filter residue is removed to obtain liquid humic acid product. The generated flash vapor enters buffer tank 5 through the third control valve 23, the fourth regulating valve 14, the fourth control valve 24 and the shell cooler 4 to cool and depressurize, forming liquid humic acid product.

[0105] The outer jacket of the buffer tank 4 is circulated with cooling water. When flash steam enters the buffer tank 4, it can further reduce the temperature and pressure, and at the same time, it forms liquid humic acid products when it is cooled.

[0106] Circulating cooling water is supplied to the shell-and-tube cooler 4 and the jacket via circulating cooling tower 6 and circulating cooling water pump 7.

[0107] The fulvic acid obtained in Examples 2-4 is shown in Table 1 below:

[0108] Example 2 5.2 3.71 Example 3 5.2 3.66 Example 4 5.2 3.51

[0109] Example 5

[0110] This embodiment provides a method for producing fulvic acid using a pilot-scale device controlled by PLC for pyrolysis, specifically including the following steps:

[0111] 1. Open the PLC system page and set the aromatic cyclization reaction temperature and time for the material;

[0112] 2. Click "Start". The PLC will automatically start the circulating cooling tower 6 and the circulating cooling water pump 7 according to the control logic.

[0113] 3. After crushing the material, take 1L of slurry with a solid content of 20%, add 1g of catalyst, and send it into reactor 2. After the feeding is completed, click "Confirm", close the pop-up window, and then enter the heating stage.

[0114] 4. During the heating stage, the heat transfer oil boiler 1 is automatically controlled by PLC to heat the heat transfer oil and the materials in the reactor 2. When the temperature of the reactor 2 reaches the aromatic cyclization reaction temperature, the reaction stage begins.

[0115] 5. During the heating stage, the PLC automatically times the reaction time until it ends, at which point cooling begins.

[0116] 6. After the timing ends, the third regulating valve 13, the fourth regulating valve 14, the third control valve 23 and the fourth control valve 24 will be opened automatically, and the first regulating valve 11 and the second regulating valve 12 will be closed. When the temperature of the reactor drops to room temperature, the thermal oil boiler 1, the circulating cooling tower 6 and the circulating cooling water pump 7 will be shut down automatically in sequence.

[0117] 7. Open the second control valve 22 and the fifth control valve 25 to discharge the material. After discharge, the material is collected, filtered, and separated into solid and liquid components before testing.

[0118] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0119] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for producing humic acid by pyrolysis, characterized in that, Includes the following steps: S1 Preprocessing Leftover food, fruit peels, and vegetable scraps are poured into the feed inlet of a grinder and ground into a fine powder. At the same time, water is added to adjust the slurry to a solids content of 5% to 30%. S2 hydrothermal degradation conversion Add dipotassium hydrogen phosphate to the above slurry and send the slurry into the reactor. Control the temperature of the reactor by using a thermal oil boiler so that the material in the reactor undergoes anaerobic reaction, dehydration polymerization reaction and aromatic cyclization reaction in sequence to obtain fulvic acid. S3 Cooling and Discharge After most of the liquid in the reactor is cooled naturally, it is discharged from the reactor outlet. The gas generated in the reactor enters the buffer tank through the third control valve, the fourth regulating valve, the fourth control valve and the shell cooler to cool and depressurize, forming liquid organic fertilizer products. The apparatus used in the method includes: a thermal oil boiler, a grinding mill, a reaction vessel, a shell-and-tube cooler, a buffer tank, a circulating cooling tower, and a circulating cooling water pump; The thermal oil boiler is circulated and connected to the reaction vessel. The grinding mill is connected in sequence to the reaction vessel and the buffer tank; The sleeve cooler is installed on the pipeline between the reactor and the buffer tank; The shell-and-tube cooler is also connected in sequence to the circulating cooling tower, the circulating cooling water pump, and the buffer tank. The buffer tank is also connected to the shell-and-tube cooler and the circulating cooling tower, respectively. A third control valve, a fourth regulating valve, and a fourth control valve are sequentially installed between the reactor and the casing cooler.

2. The method for producing humic acid by pyrolysis according to claim 1, characterized in that, The two pipelines connecting the thermal oil boiler and the reactor are respectively equipped with a first regulating valve and a second regulating valve.

3. The method for producing humic acid by pyrolysis according to claim 2, characterized in that, A bypass is provided between the thermal oil boiler and the first regulating valve, and between the thermal oil boiler and the second regulating valve, and a third regulating valve is provided on the bypass.

4. The method for producing humic acid by pyrolysis according to claim 3, characterized in that, A first control valve is provided between the grinding mill and the reaction vessel; a second control valve is provided at the bottom of the reaction vessel.

5. The method for producing humic acid by pyrolysis according to claim 4, characterized in that, A sixth control valve is provided between the circulating cooling water pump and the buffer tank; a fifth control valve is provided at the bottom of the buffer tank.

6. The method for producing humic acid by pyrolysis according to claim 5, characterized in that, The reactor is equipped with a jacket, which has a heat transfer oil inlet and a heat transfer oil outlet. The heat transfer oil inlet is connected to the first regulating valve, and the heat transfer oil outlet is connected to the second regulating valve. The thermal oil boiler, reaction vessel, circulating cooling water pump, and buffer tank are all equipped with temperature and pressure sensors.

7. The method for producing humic acid by pyrolysis according to claim 1, characterized in that, In step S2, the mass ratio of dipotassium hydrogen phosphate to the slurry is (1:1000) to (1:100). The anaerobic reaction temperature is 10~70℃, the time is 10~30min, and the pressure is <0.04MPa; The dehydration polymerization reaction is carried out at a temperature of 80~140℃, a time of 30~80min, and a pressure of 0.04~0.37MPa. The aryl cyclization reaction is carried out at a pressure of 1~1.6 MPa, a temperature of 180℃~200℃, and a reaction time of 20~100 min.

8. The method for producing humic acid by pyrolysis according to claim 7, characterized in that, The buffer tank is equipped with a jacket on its outer layer, and circulating cooling water is provided to the jacket cooler and the jacket through a circulating cooling tower and a circulating cooling water pump.

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