Pyrolysis-anaerobic fermentation combined device and method for recycling repaired plants

Abstract

According to the pyrolysis-anaerobic fermentation combined device and method for resourceful utilization of the repaired plants, by arranging a two-stage treatment system and an intelligent control strategy, harmless treatment and resource utilization of the repaired plants are achieved; the pre-pyrolysis system realizes vitrification stable solidification of aluminosilicate of heavy metal at 500-600 DEG C, and can reach the standard for resource utilization; the rear anaerobic fermentation system performs efficient fermentation by utilizing wood vinegar and waste heat generated by pyrolysis, and produced biogas realizes energy self-sufficiency; the integrated heavy metal trap and the molecular sieve filter ensure zero emission of heavy metals in tail gas; the intelligent control system optimizes operation parameters in real time through an energy efficiency model and a gas production dynamics model, and the system stability and the resource output efficiency are improved. The whole system has the characteristics of high heavy metal curing rate, strong energy self-sufficiency, high automation degree and extremely low secondary pollution risk, and a feasible scheme is provided for safe disposal and high-value conversion of wastes after phytoremediation.

Description

Technical Field

[0001] This invention relates to the field of remediation plant resource utilization technology, and in particular to a pyrolysis-anaerobic fermentation combined device and method for remediation plant resource utilization. Background Technology

[0002] With the rapid development of industrialization and agricultural modernization, soil heavy metal pollution has become an increasingly prominent problem, posing a serious threat to ecosystems and human health. Phytoremediation technology, due to its advantages such as low cost, environmental friendliness, and applicability to large-scale contaminated sites, is widely used in the remediation of heavy metal-contaminated soils. This technology utilizes hyperaccumulating plants to absorb and accumulate heavy metals in the soil, thereby reducing the heavy metal content. However, the safe disposal of the heavy metal-accumulating plant matter produced after phytoremediation has become a critical issue that urgently needs to be addressed. Improper disposal, such as indiscriminate dumping or incineration, may lead to the re-release of heavy metals into the environment, causing secondary pollution and severely undermining the environmental benefits of phytoremediation.

[0003] Currently, the main methods for disposing of plants enriched with heavy metals include landfill, incineration, composting, and pyrolysis. Landfilling is simple and easy to implement, but it consumes land resources and carries the risk of heavy metal leaching. Incineration can significantly reduce volume, but heavy metals are easily volatilized into the atmosphere at high temperatures, resulting in high concentrations of heavy metals in fly ash and bottom ash, and high treatment costs. Composting can realize the resource utilization of organic matter, but heavy metals remain active in compost products, limiting their agricultural value. Pyrolysis technology can convert plants into biochar under anaerobic conditions and stabilize heavy metals, but single pyrolysis treatment has high energy consumption, and the generated pyrolysis gas and bio-oil still pose environmental risks if not properly utilized.

[0004] Existing technologies, such as patent documents CN111518682A and CN116217026A, disclose organic waste treatment systems based on a combined pyrolysis-anaerobic fermentation process. However, these systems primarily target common organic wastes such as livestock and poultry manure and straw, and do not address the specific treatment of plants that accumulate heavy metals. These plants contain complex forms and high concentrations of heavy metals, posing higher requirements for temperature control during pyrolysis, waste gas treatment, and the safe utilization of the products. Furthermore, existing devices still have shortcomings in energy cascade utilization, closed-loop control of pollutants, and intelligent operation; the system's energy efficiency and resource utilization level need to be improved.

[0005] Therefore, there is an urgent need in this field to develop an efficient, safe, and resource-efficient treatment device and method for plants that accumulate heavy metals, which can achieve the stabilization of heavy metals, energy self-sufficiency, and high-value utilization of products, fundamentally avoiding the risk of secondary pollution and improving the environmental and economic sustainability of phytoremediation technology. Summary of the Invention

[0006] The purpose of this invention is to provide a combined pyrolysis-anaerobic fermentation device and method for the resource recovery of reclaimed plants, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a pyrolysis-anaerobic fermentation combined device for the resource utilization of reclaimed plants, comprising:

[0009] The feeding system is used to continuously and in a closed manner transport the crushed and pre-dried heavy metal-enriched plant material to the pyrolysis stage.

[0010] A pre-loaded rotary kiln pyrolysis furnace, connected to the feeding system, is used to pyrolyze plants under anaerobic conditions of 500-600℃, converting them into biochar and achieving vitrification and solidification of heavy metals in aluminosilicates.

[0011] A heavy metal trap, connected to the gas outlet of the pre-rotary kiln pyrolysis furnace, includes a cyclone separator, a molecular sieve filter, and an activated carbon adsorption tank, for capturing heavy metal vapors and pollutants in the pyrolysis gas.

[0012] A condensation system, connected to the heavy metal collector, is used to condense and separate the pyrolysis gas into wood vinegar and pyrolysis gas;

[0013] The waste heat recovery system is connected to the pre-rotary kiln pyrolysis furnace and the condensation system to recover the waste heat from the flue gas and biochar and convert it into a heat medium.

[0014] The post-anaerobic fermenter is connected to the wood vinegar outlet of the condensation system and the heat medium outlet of the waste heat recovery system, and is used to carry out anaerobic fermentation under medium or high temperature conditions to produce biogas and biogas fertilizer.

[0015] A solid-liquid separator is connected to the discharge port of the anaerobic digester and is used to separate biogas residue and biogas slurry;

[0016] The intelligent control system connects to the sensors and actuators of each component to monitor and optimize operating parameters in real time, and to execute energy balance and gas production prediction algorithms.

[0017] Preferably, the feeding system includes a belt conveyor, a screw feeder, and a closed silo, wherein the material conveyed by the feeding system has a moisture content of less than or equal to 15% and a particle size of 2-5 cm.

[0018] Preferably, the pre-rotary kiln pyrolysis furnace is equipped with an inert gas inlet, a first temperature sensor and a first stirrer, and the pyrolysis residence time is 20-40 minutes.

[0019] Preferably, the molecular sieve filter of the heavy metal trap is a zeolite molecular sieve, and the activated carbon adsorption tank is used to adsorb dioxins and organic pollutants.

[0020] Preferably, the waste heat recovery system includes a flue gas-water heat exchanger and a biochar-cooled waste heat recovery unit, with hot water or low-pressure steam as the heat medium.

[0021] Preferably, the post-anaerobic fermenter is equipped with a second stirrer, a pH sensor, a second temperature sensor and a biogas collector, and the fermentation temperature is controlled at 35±1℃ or 55±1℃.

[0022] Preferably, the intelligent control system integrates a pyrolysis energy efficiency model and an anaerobic fermentation gas production prediction model;

[0023] The formula for the pyrolysis energy efficiency model is:

[0024]

[0025] Where, η pyro For pyrolysis energy efficiency, E biochar E represents the calorific value of biochar. syngas E represents the calorific value of the pyrolysis gas. recovered For waste heat recovery, E input For the total input energy;

[0026] The formula for the anaerobic fermentation gas production prediction model is as follows:

[0027] G(t) = G0·[1-exp(-k·t)];

[0028] Where G(t) is the cumulative biogas production at time t, G0 is the potential maximum biogas production, and G0 = M substrate VS content BMP theoretical M substrate VS represents the total mass of the substrate. content BMP represents the volatile solids content of the substrate. theoretical t represents the theoretical methane production potential, k is the hydrolysis rate constant, and t is the fermentation time.

[0029] The present invention also provides a method for the remediation of plant resources based on the above-mentioned device, comprising the following steps:

[0030] S1. Plant pretreatment: Harvest the plants that are rich in heavy metals, crush them, and pre-dry them until the moisture content is less than or equal to 15%.

[0031] S2. Pyrolysis treatment: The pretreated plants are pyrolyzed at 500-600℃ under anaerobic conditions for 20-40 minutes to generate biochar and pyrolysis gas.

[0032] S3. Gas purification and condensation: After being purified by a heavy metal trap, the pyrolysis gas is condensed and separated into wood vinegar and pyrolysis gas.

[0033] S4. Waste heat recovery: using waste heat from flue gas and biochar to generate a heat transfer medium;

[0034] S5. Anaerobic fermentation: Wood vinegar is mixed with organic residues, and the residual heat is used to maintain the fermentation temperature for anaerobic fermentation.

[0035] S6. Biogas fertilizer treatment: After fermentation, the biogas residue and biogas slurry are separated and utilized as resources respectively.

[0036] S7. Intelligent control, based on real-time data to run energy efficiency and gas production prediction models, optimizes system operating parameters.

[0037] Preferably, in step S5, the organic residue has a carbon-to-nitrogen ratio of (20-30):1.

[0038] Preferably, in step S7, the potential maximum biogas production G0 and hydrolysis rate constant k of the gas production prediction model are established in a database through batch experiments, and the gas production is called and predicted in real time to control the feed ratio and fermentation conditions.

[0039] The present invention achieves the following beneficial technical effects compared to the prior art:

[0040] This invention provides a pyrolysis-anaerobic fermentation combined device and method for the resource utilization of remediated phytoremediation plants. By setting up a two-stage treatment system and intelligent control strategy, it achieves the harmless disposal and resource utilization of remediated plants. The pre-pyrolysis system achieves stable vitrification and solidification of heavy metals into aluminosilicates at 500-600℃, enabling compliant resource utilization. The post-anaerobic fermentation system utilizes the wood vinegar and waste heat generated by pyrolysis for efficient fermentation, producing biogas for energy self-sufficiency. An integrated heavy metal trap and molecular sieve filter ensure zero heavy metal emissions in the exhaust gas. The intelligent control system optimizes operating parameters in real time through energy efficiency and gas production kinetic models, improving system stability and resource output efficiency. The overall system features high heavy metal solidification rate, strong energy self-sufficiency, high automation, and extremely low risk of secondary pollution, providing a feasible solution for the safe disposal and high-value conversion of waste from phytoremediation. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram of the pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants provided by the present invention.

[0043] Figure 2 This is a schematic diagram of the method for resource utilization of remediated plants provided by the present invention;

[0044] In the diagram: 1: Feeding system, 2: Pre-rotary kiln pyrolysis furnace, 3: Heavy metal trap, 4: Condensation system, 5: Waste heat recovery system, 6: Post-anaerobic fermenter, 7: Solid-liquid separator. Detailed Implementation

[0045] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] 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.

[0048] The purpose of this invention is to provide a combined pyrolysis-anaerobic fermentation device and method for the resource recovery of reclaimed plants, in order to solve the problems existing in the prior art.

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1:

[0051] This embodiment provides a combined pyrolysis-anaerobic fermentation device for the resource utilization of remediated plants, such as... Figure 1 As shown, the entire device is arranged sequentially as follows: feeding system 1, pre-rotary kiln pyrolysis furnace 2, heavy metal trap 3, condensation system 4, waste heat recovery system 5, post-anaerobic fermentation tank 6, and solid-liquid separator 7. Closed-loop control is achieved through an intelligent control system. Feeding system 1 is located at the front end of the device. Its belt conveyor continuously transports the heavy metal-enriched plants (moisture content ≤15%, particle size 2-5cm) pre-dried by outdoor solar energy to a screw feeder. The screw feeder outlet is connected to a sealed silo, which is filled with nitrogen to maintain a slight positive pressure and prevent air infiltration. A variable frequency speed-regulating rotary discharge valve is installed at the bottom of the silo, which can adjust the feeding rate in real time according to the material level signal inside the rotary kiln, achieving "continuous, sealed, and quantitative" feeding.

[0052] The pre-rotary kiln pyrolysis furnace 2 adopts a horizontal external heating structure. The outer shell is made of 310S stainless steel, and the inner lining is 10mm thick Al-Si refractory castable. The kiln body has a length-to-diameter ratio of approximately 6:1, and the rotation speed is adjustable from 0.5-2 r / min. An inert gas inlet is located at the kiln head, and the nitrogen flow rate is controlled by a closed-loop mass flow meter to ensure the oxygen content inside the furnace is below 0.5 vol%. A first agitator is arranged in the middle of the kiln body, with a 5mm gap between the impeller and the kiln wall. Mechanical agitation ensures uniform heating of the material, and the residence time is stabilized at 20-40 minutes. Three sections of electric heating jackets are installed outside the kiln body, each equipped with a K-type thermocouple as the primary temperature sensor. The signals are connected to the intelligent control system, which uses a PID algorithm to precisely control the kiln temperature between 500-600℃. This temperature range promotes the pyrolysis of plant cellulose and hemicellulose and induces heavy metals to form stable glassy aluminosilicates with Si and Al, thereby achieving the "vitrification and solidification" of heavy metals.

[0053] The high-temperature, dust-laden flue gas generated from pyrolysis first enters the heavy metal collector 3. This collector consists of a cyclone separator, a molecular sieve filter, and an activated carbon adsorption tank connected in series. The inlet velocity of the cyclone separator is maintained at 18-22 m / s, performing primary separation of particles with a diameter ≥5 μm. The airflow then enters the molecular sieve filter, which is filled with La-modified 5A zeolite molecular sieves with a bed thickness of 300 mm and an operating temperature of 180℃. The adsorption efficiency for heavy metal vapors such as Pb, Cd, and Zn is >99%. The final activated carbon adsorption tank is filled with coconut shell activated carbon with an iodine value ≥1000 mg / g and a bed space velocity of 0.2 s⁻¹. -1 It is used to capture residual dioxins and polycyclic aromatic hydrocarbons, ensuring that the concentrations of heavy metals and organic pollutants in the exhaust gas are lower than the national emission standard limits.

[0054] The purified pyrolysis gas then enters the condensation system 4. This condensation system uses two-stage plate heat exchangers connected in series. The first-stage cooling medium is circulating cooling water (30℃), and the second-stage is an ethylene glycol aqueous solution (-10℃), which allows the condensable components to be fully condensed into wood vinegar. The non-condensable pyrolysis gas (mainly composed of CO, H, CH, and CO) enters the pyrolysis gas buffer tank. A portion of the pyrolysis gas is piped back to the pyrolysis furnace burner as auxiliary fuel, while the remainder can be mixed and utilized in the biogas system. After passing through a flame arrester, it enters the gas phase zone of the post-anaerobic fermentation tank 6 as a stirring or gas lift power source. The wood vinegar collection tank is made of 316L stainless steel and is equipped with a liquid level sensor. When the liquid level reaches the set upper limit, a corrosion-resistant diaphragm pump is automatically started to pump the wood vinegar into the anaerobic fermentation tank in a metered manner, realizing "pyrolysis liquid reuse".

[0055] The waste heat recovery system 5 recovers two parts of waste heat simultaneously: one is the kiln tail flue gas, with a temperature of approximately 450℃, which heats ambient temperature water to 90℃ via a flue gas-water heat exchanger; the other is the biochar exiting the kiln, with a temperature of approximately 500℃, which is cooled to <50℃ via U-shaped water-cooling pipes embedded in a spiral cooler, while the cooling water is heated to 80℃. The two parts of hot water are collected in an insulated storage tank, serving as a constant temperature medium for the subsequent anaerobic fermentation tank. A pressure relief valve is installed at the top of the storage tank to prevent steam overpressure; a variable frequency circulating pump is installed at the bottom, automatically adjusting the flow rate based on feedback from a second temperature sensor inside the fermentation tank to ensure the fermentation temperature remains constant at 35±1℃ (medium-temperature mode) or 55±1℃ (high-temperature mode).

[0056] Post-anaerobic fermenter 6 is a fully mixed CSTR reactor with an effective volume of 50m³. 3 The tank is lined with an enamel anti-corrosion layer and equipped with a biogas collector on top. After desulfurization and dehydration, the biogas is sent to the storage tank. A second agitator with variable frequency speed control is installed inside the tank, with hyperboloid blades and an adjustable speed of 0-20 r / min. Signals from pH, ORP, a second temperature sensor, a level gauge, and a gas flow meter are all connected to the intelligent control system. The fermentation substrate is wood vinegar and readily available corn stalk hydrolysate, mixed at a C / N ratio of (20-30):1. A substrate database is established through batch experiments. Based on the real-time measured volatile solids content (VS), the system calls the gas production prediction model to calculate the potential maximum biogas production G0 and the hydrolysis rate constant k, thereby predicting the cumulative gas production M(t) at any given time t. When the deviation between the predicted and measured values ​​exceeds 5%, the system automatically adjusts the feed ratio, stirring intensity, or temperature setting to achieve precise "data-driven" control.

[0057] After fermentation, the mixture is separated into biogas residue and biogas slurry by a solid-liquid separator 7 (horizontal screw centrifuge, speed 3500 r / min). The biogas residue has a moisture content of <60% and can be directly made into organic-inorganic compound fertilizer; the biogas slurry can be concentrated by membrane and used as liquid fertilizer, or it can be refluxed and diluted for the next round of fermentation to achieve "nutrient closed loop".

[0058] The intelligent control system is centered around an industrial PC and communicates with various sensors and actuators via the Modbus-RTU protocol. The system incorporates two key models:

[0059] The formula for the pyrolysis energy efficiency model is:

[0060]

[0061] Where, η pyro For pyrolysis energy efficiency, E biochar E represents the calorific value of biochar. syngas E represents the calorific value of the pyrolysis gas. recovered For waste heat recovery, E input Input the total energy; calculate the energy efficiency under the current operating conditions in real time; if η < 75%, automatically increase the electric heating power to compensate or extend the residence time;

[0062] The formula for the anaerobic fermentation gas production prediction model is:

[0063] G(t) = G0·[1-exp(-k·t)];

[0064] Where G(t) is the cumulative biogas production at time t, G0 is the potential maximum biogas production, and G0 = M substrate VS content BMP theoretical M substrate VS represents the total mass of the substrate. content BMP represents the volatile solids content of the substrate. theoretical The theoretical methane production potential is given by k, the hydrolysis rate constant, and t, the fermentation time. The system performs rolling correction on k based on the measured gas production of the previous 24 hours every morning. When the deviation is >5%, the "adaptive optimization" subroutine is triggered to adjust the stirring rate, reflux ratio, or alkalinity to ensure prediction accuracy.

[0065] In addition, the system also integrates a fault prediction module: by decomposing wavelet packets of signals such as temperature, pressure, and vibration and training LSTM neural networks, it can provide early warning of possible equipment anomalies 3-5 hours in advance, significantly reducing unplanned downtime.

[0066] Example 2:

[0067] This embodiment provides a method for the remediation of plant resources using the above-mentioned device, such as... Figure 2 As shown, it includes the following steps:

[0068] S1. Plant pretreatment and feeding

[0069] Centipede grass plants, which are rich in heavy metals (such as Cd and Pb), are harvested from the field and naturally sun-dried, supplemented by low-temperature airflow drying, to reduce their moisture content to about 12%. They are then crushed into 3-4 cm segments using a twin-shaft shear crusher. These segments are then conveyed to a temporary storage silo via a closed belt conveyor, and finally fed continuously and stably into the pre-loaded rotary kiln pyrolysis furnace by a frequency converter-controlled screw feeder at a rate of 150 kg / h.

[0070] S2. Controlled pyrolysis and heavy metal solidification

[0071] The rotary kiln pyrolysis furnace is started, and high-purity nitrogen (99.99% purity) is first introduced to replace the atmosphere inside the furnace, ensuring an oxygen-free environment. Then, the furnace temperature is increased to the set temperature of 580℃±10℃ at a rate of 10℃ / min using a natural gas-assisted burner, with the material remaining in the furnace for approximately 30 minutes. Under these conditions, the organic matter in the plant material undergoes thermal decomposition, producing biochar, pyrolysis gas, and bio-oil vapor. Simultaneously, heavy metals (Cd, Pb) in the plant material react with components such as silicon, aluminum, and potassium in the biomass ash, being solidified in situ within the biochar matrix to form a stable aluminosilicate glass. The solid biochar product produced by pyrolysis is discharged from the furnace tail and enters the biochar discharge cooler for rapid cooling to terminate the reaction and prevent the re-evaporation of heavy metals.

[0072] S3. Purification and separation of pyrolysis products

[0073] The high-temperature pyrolysis gas first enters the heavy metal trap. It first passes through a cyclone separator to remove larger particulate dust; then it enters a molecular sieve filter to selectively adsorb gaseous heavy metals and their chlorides; finally, it passes through an activated carbon adsorption tank for further deep removal of residual trace heavy metals and potential dioxin-like pollutants. The purified pyrolysis gas enters the condensation system, where it is indirectly cooled to below 40°C using circulating cooling water, causing most of the bio-oil vapor and moisture to condense into wood vinegar, which is collected in a wood vinegar storage tank. The non-condensable pyrolysis gas (mainly composed of CO, H₂, CH₄, and CO) enters the pyrolysis gas buffer tank; its calorific value, measured by an online gas analyzer, is approximately 12 MJ / Nm³. 3 A portion of the pyrolysis gas is piped back to the pyrolysis furnace burner as auxiliary fuel, while the remainder can be mixed and utilized in the biogas system. The purified exhaust gas is drawn in by an induced draft fan and discharged after passing testing.

[0074] S4. Waste Heat Recovery

[0075] The high-temperature flue gas discharged from the pyrolysis furnace enters the waste heat boiler, where it exchanges heat with soft water to generate saturated steam at 0.6 MPa. The high-temperature biochar undergoes indirect heat exchange with circulating cooling water in the discharge cooler, raising the water temperature. The generated steam and hot water are then transported through insulated pipes to the jacketed coils of the post-anaerobic fermenter to maintain its fermentation temperature.

[0076] S5. Anaerobic fermentation to produce biogas

[0077] The collected wood vinegar and organic residue were used as a mixed fermentation feedstock and pumped into a post-anaerobic fermenter. This fermenter was a completely mixed type with an effective volume of 50 m³. 3 Utilizing heat energy from a waste heat system, the fermentation temperature inside the tank is precisely controlled at 35℃±1℃ (mesothermal fermentation) via a PLC control system. An intelligent control system monitors parameters such as pH and redox potential in real time. Anaerobic microorganisms degrade organic matter to produce biogas, with an average daily biogas production of approximately 120 m³. 3 The methane content in biogas remains stable at 58%-62%.

[0078] S6. Biogas Fertilizer Utilization and System Closed Loop

[0079] The fermented digestate is discharged from the bottom of the anaerobic digester and enters the solid-liquid separator. Part of the separated biogas slurry is recycled to adjust the feed concentration to the digester, and part is sold as high-quality liquid fertilizer. The biogas residue, due to its extremely low heavy metal content (derived from trace minerals in manure and wood vinegar), is processed into solid organic fertilizer through aerobic composting. The generated biogas, after desulfurization and dehydration purification, is used partly to drive the burners in the pyrolysis furnace and partly to generate electricity to power the system equipment, achieving energy self-sufficiency.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0082] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A pyrolysis-anaerobic fermentation combined device for the resource utilization of reclaimed plants, characterized in that, include: The feeding system (1) is used to continuously and tightly transport the crushed and pre-dried heavy metal-enriched plant material to the pyrolysis stage. The pre-rotary kiln pyrolysis furnace (2) is connected to the feeding system (1) and is used to pyrolyze plants under anaerobic conditions of 500-600℃, so as to convert them into biochar and achieve the vitrification and solidification of heavy metals in aluminosilicates. The heavy metal trap (3) is connected to the gas outlet of the pre-rotary kiln pyrolysis furnace (2) and includes a cyclone separator, a molecular sieve filter and an activated carbon adsorption tank for trapping heavy metal vapor and pollutants in the pyrolysis gas. A condensation system (4) is connected to the heavy metal collector (3) for condensing and separating pyrolysis gas into wood vinegar and pyrolysis gas; The waste heat recovery system (5) is connected to the pre-rotary kiln pyrolysis furnace (2) and the condensation system (4) to recover the waste heat of flue gas and biochar and convert it into a heat medium; The post-anaerobic fermentation tank (6) is connected to the wood vinegar outlet of the condensation system (4) and the heat medium outlet of the waste heat recovery system (5) for anaerobic fermentation under medium or high temperature conditions to produce biogas and biogas fertilizer. A solid-liquid separator (7) is connected to the discharge port of the anaerobic fermenter (6) and is used to separate biogas residue and biogas slurry; The intelligent control system connects to the sensors and actuators of each component to monitor and optimize operating parameters in real time, and to execute energy balance and gas production prediction algorithms.

2. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The feeding system (1) includes a belt conveyor, a screw feeder and a closed silo. The material conveyed by the feeding system (1) has a moisture content of less than or equal to 15% and a particle size of 2-5 cm.

3. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The pre-rotary kiln pyrolysis furnace (2) is equipped with an inert gas inlet, a first temperature sensor and a first stirrer, and the pyrolysis residence time is 20-40 min.

4. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The molecular sieve filter of the heavy metal trap (3) is made of zeolite molecular sieve, and the activated carbon adsorption tank is used to adsorb dioxins and organic pollutants.

5. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The waste heat recovery system (5) includes a flue gas-water heat exchanger and a biochar-cooled waste heat recovery unit, with hot water or low-pressure steam as the heat medium.

6. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The post-anaerobic fermenter (6) is equipped with a second stirrer, a pH sensor, a second temperature sensor and a biogas collector, and the fermentation temperature is controlled at 35±1℃ or 55±1℃.

7. The pyrolysis-anaerobic fermentation combined device for the resource utilization of remediated plants according to claim 1, characterized in that, The intelligent control system integrates a pyrolysis energy efficiency model and an anaerobic fermentation gas production prediction model. The formula for the pyrolysis energy efficiency model is: Where, η pyro For pyrolysis energy efficiency, E biochar E represents the calorific value of biochar. syngas E represents the calorific value of the pyrolysis gas. recovered For waste heat recovery, E input For the total input energy; The formula for the anaerobic fermentation gas production prediction model is as follows: G(t) = G0·[1-exp(-k·t)]; Where G(t) is the cumulative biogas production at time t, G0 is the potential maximum biogas production, and G0 = M substrate VS content BMP theoretical M substrate VS represents the total mass of the substrate. content BMP represents the volatile solids content of the substrate. theoretical t represents the theoretical methane production potential, k is the hydrolysis rate constant, and t is the fermentation time.

8. A method for post-remediation plant resource recovery based on the apparatus according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Plant pretreatment: Harvest the plants that are rich in heavy metals, crush them, and pre-dry them until the moisture content is less than or equal to 15%. S2. Pyrolysis treatment: The pretreated plants are pyrolyzed at 500-600℃ under anaerobic conditions for 20-40 minutes to generate biochar and pyrolysis gas. S3. Gas purification and condensation: After being purified by a heavy metal trap, the pyrolysis gas is condensed and separated into wood vinegar and pyrolysis gas. S4. Waste heat recovery: using waste heat from flue gas and biochar to generate a heat transfer medium; S5. Anaerobic fermentation: Wood vinegar is mixed with organic residues, and the residual heat is used to maintain the fermentation temperature for anaerobic fermentation. S6. Biogas fertilizer treatment: After fermentation, the biogas residue and biogas slurry are separated and utilized as resources respectively. S7. Intelligent control, based on real-time data to run energy efficiency and gas production prediction models, optimizes system operating parameters.

9. The method for post-remediation plant resource utilization according to claim 8, characterized in that, In step S5, the organic residue has a carbon-to-nitrogen ratio of (20-30):

1.

10. The method for post-remediation plant resource utilization according to claim 8, characterized in that, In step S7, the potential maximum biogas production G0 and hydrolysis rate constant k of the gas production prediction model are used to establish a database through batch experiments, and the gas production is called and predicted in real time to control the feed ratio and fermentation conditions.

Images