Co-pyrolysis system and method based on ash content regulation and dynamic wrapping

Abstract

The invention relates to the technical field of biomass energy and waste plastic treatment, and provides a co-pyrolysis system and method based on ash content regulation and dynamic wrapping, the system comprises: a biomass feeding unit, the biomass feeding unit comprises a first screw feeder; the waste plastic feeding unit comprises a second screw feeder; an inlet of the mixed reaction chamber is communicated with a discharge port of the first screw feeder and a discharge port of the second screw feeder, and a partition plate is arranged in the mixed reaction chamber; a spiral guide plate is arranged in the cracking reaction chamber, and the upper end of the cracking reaction chamber is communicated with the mixing reaction chamber through two channels; a combustion chamber, a cyclone separator and an ash content rotation pipeline. According to the co-pyrolysis system based on ash content regulation and dynamic wrapping, grading efficient conversion of light and heavy components is achieved, and the yield and quality of pyrolysis oil are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass energy and waste plastic treatment, in particular to a co-pyrolysis system and method based on ash regulation and dynamic wrapping. BACKGROUND

[0002] Biomass, as a renewable energy with abundant reserves, plays an important role in low-carbon energy transformation. However, biomass itself has low hydrogen content and high oxygen content, and the pyrolysis oil produced by single biomass pyrolysis has low calorific value, poor stability, and is prone to aging and deterioration, which limits its large-scale application. Waste plastics have the characteristics of high hydrogen and low oxygen, and co-pyrolysis with biomass can supplement the hydrogen needed for biomass pyrolysis, improve the hydrogen-oxygen ratio to improve the quality of pyrolysis oil, and at the same time avoid environmental pollution caused by waste plastic landfill or incineration, achieving the dual goals of "waste treatment and resource recycling".

[0003] However, the existing co-pyrolysis technology of biomass and waste plastics still has many key bottlenecks: 1. Heat and mass transfer obstacles caused by static mixing: As disclosed in patent CN116286042A, the co-pyrolysis equipment mixes and crushes the biomass and waste plastics, and then pyrolyzes them. The plastic melts and wraps the biomass particles as a whole, forming a dense heat transfer barrier that hinders heat transfer and the release of biomass volatiles, and inhibits the synergistic effect of the two. Moreover, this method can only produce biochar, and cannot form bio-ash, making it difficult to achieve the synergistic effect of ash and volatile matter.

[0004] 2. Uneven distribution of reaction temperature: As disclosed in patent CN118931596A, the split co-gasification system has the problem that the volatiles of the two materials react in the fluidized medium, and the continuous endothermic reaction causes the temperature in the reactor to be low at the top and high at the bottom, resulting in imbalance in the cracking of light and heavy components - when the temperature is suitable at the bottom, the cracking of heavy hydrocarbons at the top is not sufficient, and when the temperature is suitable at the top, the cracking of light hydrocarbons at the bottom is excessive, ultimately leading to low yield and poor quality of pyrolysis oil.

[0005] 3. Fluidized bed instability: The above-mentioned fluidized bed process requires crushing and sieving of raw materials, and the high-viscosity material produced by the melting of plastics easily wraps the bed material particles, causing loss of fluidization and affecting the continuous and stable operation of the equipment.

[0006] In summary, the key bottlenecks of the conventional technology are embodied in the following two aspects: (1) The existing process relies on static mixing, and the plastic is passively wrapped around the biomass particles after melting, forming a dense clump structure of "biomass core-plastic shell". This structure seriously hinders the heat transfer to the biomass core and inhibits the release of biomass volatile matter, making it difficult for effective synergistic reaction to occur between the two phases. (2) The system lacks active means to regulate the temperature distribution inside the reactor, and cannot build a temperature gradient that adapts to the differential cracking needs of light and heavy volatile matter. This leads to excessive cracking of light components and insufficient cracking of heavy components, making it difficult to optimize the overall product quality and yield. SUMMARY

[0007] In view of the defects in the prior art, the purpose of the present application is to provide a co-pyrolysis system based on ash control and dynamic wrapping, which strengthens the contact between the two phases through a dynamic wrapping mechanism and controls the temperature gradient through ash diversion, achieving efficient conversion of light and heavy components and improving the yield and quality of cracked oil.

[0008] According to a first aspect of the present application, a co-pyrolysis system based on ash control and dynamic wrapping is provided, comprising: a biomass feeding unit, the biomass feeding unit comprising a first screw feeder for conveying unbroken biomass, the first screw feeder having a flue gas heating channel thereon; a waste plastic feeding unit, the waste plastic feeding unit comprising a second screw feeder for conveying unbroken waste plastic, the second screw feeder being located below the first screw feeder; a mixing reaction chamber, the inlet of the mixing reaction chamber being in communication with the discharge port of the first screw feeder and the discharge port of the second screw feeder, the interior of the mixing reaction chamber being provided with a partition plate, the partition plate being located below the discharge port of the second screw feeder, and a plurality of apertures being formed in the partition plate; a cracking reaction chamber, the interior of the cracking reaction chamber being provided with a spiral guide plate, and the upper end of the cracking reaction chamber being in communication with the mixing reaction chamber through two channels respectively; a combustion chamber, a cyclone separator and an ash return pipe, the combustion chamber being in communication with the lower end of the cracking reaction chamber, the inlet of the cyclone separator being in communication with the flue gas outlet of the combustion chamber, the solid ash outlet of the cyclone separator being in communication with the ash return pipe, and the ash return pipe comprising a first branch and a second branch, the first branch and the second branch being in communication with the lower part and the upper part of the cracking reaction chamber respectively.

[0009] Further, the interior of the mixing reaction chamber is further provided with a dispersing device, and the dispersing device is located above the partition plate.

[0010] Furthermore, it also includes an exhaust gas treatment device, the inlet of which is connected to the flue gas outlet of the flue gas heating channel, and the flue gas inlet of the flue gas heating channel is connected to the flue gas outlet of the cyclone separator.

[0011] Furthermore, it also includes a product collection unit, which includes a cooling tower and an oil storage tank. The inlet of the cooling tower is connected to the gas outlet of the pyrolysis reaction chamber, and the inlet of the oil storage tank is connected to the outlet of the cooling tower.

[0012] Furthermore, the inlet of the mixing reaction chamber is connected to the outlet of the first screw feeder through a pipeline. A circulating fan and a Laval nozzle are installed on the pipeline. The circulating fan and the Laval nozzle are used to transport the pyrolysis gas in the pipeline and the mixing reaction chamber to the pyrolysis reaction chamber.

[0013] Furthermore, the ash rotary pipeline is equipped with an ash cone valve, which is used to regulate the ash flow ratio of the first branch and the second branch.

[0014] According to a second aspect of the present invention, a co-pyrolysis method based on ash content control and dynamic encapsulation is provided, comprising the following steps: S1. Biomass pretreatment and preliminary pyrolysis: Uncrushed biomass enters the first screw feeder and undergoes preliminary pyrolysis under the preheating effect of the flue gas heating channel to generate pyrolysis gas and coke particles. S2: Waste plastic feeding and dynamic wrapping: Uncrushed waste plastic enters the second screw feeder and is conveyed to the partition to form a plastic material layer. The coke particles penetrate the plastic material layer under the action of the dispersing device. The plastic material layer is heated and melts and wraps the coke particles to form mixed particles. S3: Ash diversion and directional conveying: The high-temperature flue gas generated in the combustion chamber carries ash into the cyclone separator. The ash is discharged from the solid ash outlet of the cyclone separator and enters the first branch and the second branch. The ash flow rate entering the first branch is greater than the ash flow rate entering the second branch. S4: Staged co-pyrolysis reaction: The mixed particles enter from the top of the pyrolysis reaction chamber and move downward along the spiral guide plate. Under the catalytic action of the ash, a co-pyrolysis reaction occurs and pyrolysis gas is generated. The volatiles in the upward pyrolysis gas come into counter-current contact with the downward ash, and catalytic pyrolysis, deoxygenation and aromatization reactions continue to occur. S5: Product collection and energy recycling: The pyrolysis gas is discharged from the outlet of the pyrolysis reaction chamber, cooled by the cooling tower, and the pyrolysis oil is collected in the oil storage tank. The cooled pyrolysis gas is returned to the combustion chamber. The flue gas separated by the cyclone separator is used to preheat the biomass in the first screw feeder.

[0015] The beneficial effects of this invention are: 1. This invention provides a co-pyrolysis system based on ash content control and dynamic encapsulation, employing an innovative design of "high-level feeding + dynamic encapsulation." The first screw feeder is higher than the second screw feeder. The high-temperature coke particles generated from the initial pyrolysis of biomass are evenly spread by a dispersion device and penetrate the plastic material layer in a "meteorite rain" manner, forming mixed particles of "coke core + plastic shell." In this structure, coke acts as a high-temperature core to achieve "inside-out heat transfer," resulting in a short heat transfer path and high efficiency, completely solving the heat transfer barrier problem of the traditional "plastic shell-biomass core" structure. At the same time, the coke particles retain the abundant pores after the initial pyrolysis of biomass, providing a sufficient interface for the transfer of hydrogen elements from the plastic to the coke and volatile matter. Combined with the synergistic reaction of the cracked gas delivered by the Laval nozzle, the deoxygenation and aromatization upgrading processes are significantly enhanced.

[0016] 2. This invention provides a co-pyrolysis system based on ash content control and dynamic encapsulation. Through a dual-branch design of the ash rotary pipeline and ash cone valve regulation, it achieves directional diversion and transport of ash. The first branch transports a large flow of ash downwards, utilizing the sensible heat of the ash to maintain a high-temperature environment, ensuring sufficient release and deep pyrolysis of heavy volatiles. The second branch transports a small flow of ash upwards, maintaining a moderate temperature and preventing excessive pyrolysis of light volatiles. This design actively constructs an optimized temperature gradient of "high at the bottom and low at the top," perfectly adapting to the pyrolysis requirements of both light and heavy volatiles, solving the pyrolysis imbalance problem caused by uneven temperature distribution in traditional technologies. Simultaneously, the reverse contact between the upward-flowing volatiles and the downward-flowing ash further enhances the catalytic upgrading reaction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Reference numerals in the attached drawings: 1-First screw feeder, 2-Second screw feeder, 3-Mixing reaction chamber, 4-Cracking reaction chamber, 5-Combustion chamber, 6-Cyclone separator, 71-First branch, 72-Second branch, 73-Ash cone valve, 8-Dispersion device, 9-Tail gas treatment device, 10-Pipeline, 11-Cooling tower, 12-Oil storage tank, 13-Spiral guide plate, 14-Baffle plate, 15-Circulating fan, 16-Laval nozzle. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] In this application, unless otherwise expressly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] In the description of this application, it should be understood that the terms "longitudinal", "horizontal", "level", "top", "bottom", "upper", "lower", "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and 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, and therefore should not be construed as a limitation of the present invention.

[0022] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0023] like Figure 1 As shown, the present invention provides a co-pyrolysis system based on ash content control and dynamic encapsulation, including a biomass feeding unit, a waste plastic feeding unit, a mixing reaction chamber 3, a pyrolysis reaction chamber 4, a combustion chamber 5, a cyclone separator 6, an ash rotary pipe, a dispersion device 8, a tail gas treatment device 9, and a product collection unit.

[0024] The first screw feeder 1 of the biomass feeding unit is provided with a biomass feed inlet at the upper end and a flue gas heating channel inside. The flue gas inlet of the flue gas heating channel is connected to the flue gas outlet of the cyclone separator 6, and the flue gas outlet of the flue gas heating channel is connected to the inlet of the tail gas treatment device 9. The discharge port of the first screw feeder 1 is connected to the inlet of the mixing reaction chamber 3 through the pipe 10. A circulating fan 15 and a Laval nozzle 16 are installed in sequence on the pipe 10.

[0025] The waste plastic feeding unit has a waste plastic inlet at the upper end of the second screw feeder 2, located below the first screw feeder 1, and its outlet is connected to the inlet of the mixing reaction chamber 3. The mixing reaction chamber 3 is provided with a dispersing device 8 and a partition 14 from top to bottom. The partition 14 has several holes for the molten plastic to flow downward and wrap around the coke particles.

[0026] The lower end of the mixing reaction chamber 3 is connected to the upper end of the pyrolysis reaction chamber 4 through two channels. A spiral guide plate 13 is fixedly installed inside the pyrolysis reaction chamber 4. The lower end of the pyrolysis reaction chamber 4 is connected to the combustion chamber 5. The combustion chamber 5 is equipped with an air intake structure connected to the circulating fan 15 for blowing air to assist combustion.

[0027] The inlet of the cyclone separator 6 is connected to the flue gas outlet of the combustion chamber 5, and the solid ash outlet of the cyclone separator 6 is connected to the ash rotary pipe. The ash rotary pipe is divided into a first branch 71 and a second branch 72. The first branch 71 is connected to the lower part of the pyrolysis reaction chamber 4, and the second branch 72 is connected to the upper part of the pyrolysis reaction chamber 4. An ash cone valve 73 is installed on the ash rotary pipe.

[0028] The inlet of the cooling tower 11 of the product collection unit is connected to the outlet of the cracking reaction chamber 4, and the outlet of the cooling tower 11 is connected to the oil storage tank 12. The oil storage tank 12 is also equipped with a pipe 10 connected to the combustion chamber 5, which is used to send the cracked gas after the oil phase is separated back to the combustion chamber 5.

[0029] Working principle: After the system is started, the circulating fan 15 blows in air to prepare for the subsequent combustion reaction; the uncrushed biomass enters the first screw feeder 1 from the biomass inlet, and the high-temperature flue gas separated by the cyclone separator 6 enters the flue gas heating channel to preheat the biomass in the first screw feeder 1. Under the preheating effect, the biomass undergoes preliminary pyrolysis to generate cracked gas and coke particles.

[0030] Uncrushed waste plastic enters the second screw feeder 2 through the waste plastic inlet and is conveyed by the second screw feeder 2 to the partition 14 in the mixing reaction chamber 3 to form a uniform plastic layer. The coke particles generated by the first screw feeder 1 enter the mixing reaction chamber 3 through the pipe 10. Under the action of the dispersing device 8, they are evenly spread and penetrate the plastic layer. The sensible heat of the coke particles causes the plastic in contact to melt rapidly. The molten plastic flows downward through the pores on the partition 14, while enveloping the coke particles to form mixed particles.

[0031] The mixed particles enter the pyrolysis reaction chamber 4 through the two channels at the lower end of the mixing reaction chamber 3 and move downwards gradually along the spiral guide plate 13. At the same time, the high-temperature flue gas generated by subsequent combustion in the combustion chamber 5 carries ash into the cyclone separator 6. After the ash is separated from the flue gas, it is discharged from the solid ash outlet and enters the ash rotary pipe. The ash flow rate of the first branch 71 is greater than that of the second branch 72 by the ash cone valve 73, and is respectively transported to the lower and upper parts of the pyrolysis reaction chamber 4.

[0032] Inside the pyrolysis reaction chamber 4, the mixed particles undergo a co-pyrolysis reaction under the catalytic and heating effects of ash, producing pyrolysis gas. The large amount of ash in the lower part maintains a high-temperature environment, promoting the full release and pyrolysis of heavy volatiles, while the small amount of ash in the upper part maintains a moderate low temperature, which is conducive to the stable release of light volatiles. The volatiles in the upward-moving pyrolysis gas and the downward-moving ash come into counter-current contact, continuously undergoing catalytic pyrolysis, deoxygenation, and aromatization reactions. At the same time, the pyrolysis gas in the pipeline 10 and the mixing reaction chamber 3 is injected into the pyrolysis reaction chamber 4 through the Laval nozzle 16 under the action of the circulating fan 15, further participating in the synergistic reaction.

[0033] The pyrolysis gas generated in the pyrolysis reaction chamber 4 is discharged from the outlet and enters the cooling tower 11 for cooling. After cooling, the pyrolysis gas is separated into an oil phase in the oil storage tank 12 to obtain high-purity pyrolysis oil. The pyrolysis gas after oil phase separation is returned to the combustion chamber 5 as auxiliary fuel. The flue gas separated by the cyclone separator 6 enters the flue gas heating device through the flue gas outlet, preheats the biomass, cools it, and then is sent to the tail gas treatment device 9 through the flue gas outlet for treatment before being discharged. The solid residue after reaction in the pyrolysis reaction chamber 4 enters the combustion chamber 5. The solid residue includes biomass char and plastic char, which are burned together with the pyrolysis gas after oil separation to continuously generate high-temperature flue gas and ash, ensuring continuous operation of the system.

[0034] This invention also provides a co-pyrolysis method based on ash content control and dynamic encapsulation, comprising the following steps: S1. First, start the circulating fan 15 to blow air into the combustion chamber 5, and at the same time open the flue gas passage between the cyclone separator 6 and the first screw feeder 1 (the initial high-temperature flue gas can be provided by the auxiliary heat source during the first start-up, and the subsequent operation relies on the system's own energy circulation). Feed the uncrushed biomass raw material into the first screw feeder 1 from the biomass inlet. The first screw feeder 1 starts and conveys the biomass. During the conveying process, the biomass exchanges heat with the high-temperature flue gas in the flue gas heating passage, gradually increases in temperature and undergoes preliminary pyrolysis, generating cracked gas and high-temperature coke particles. The cracked gas is temporarily stored in the pipeline 10, and the coke particles continue to fall in the conveying direction. S2: Simultaneously with the initial pyrolysis of biomass, uncrushed waste plastic is fed into the second screw feeder 2 through the waste plastic inlet. The second screw feeder 2 starts and conveys the waste plastic to the partition 14 inside the mixing reaction chamber 3, where the waste plastic naturally accumulates to form a uniform plastic layer. High-temperature coke particles conveyed by the first screw feeder 1 enter the mixing reaction chamber 3 through pipe 10 and fall into the dispersion device 8. The structure of the dispersion device 8 is similar to a mosquito coil tower, ensuring that the coke particles fall evenly, allowing them to penetrate the plastic layer on the partition 14 like a "meteor shower." The sensible heat of the coke particles is instantly transferred to the plastic they contact, causing the plastic to melt rapidly and selectively. The molten plastic flows downward through the pores on the partition 14, actively enveloping the coke particles below during its descent, forming a mixed particle of "coke core + molten plastic outer layer." The mixed particle enters the pyrolysis reaction chamber 4 through two channels at the lower end of the mixing reaction chamber 3. S3: As the mixed particles enter the pyrolysis reaction chamber 4, a small amount of auxiliary fuel is added to the combustion chamber 5 (used only during the initial start-up; subsequent combustion relies on the solid residue and recovered pyrolysis gas). The combustion of the auxiliary fuel generates a high-temperature environment, ensuring the complete combustion of the solid residue (biochar and plastic char) falling from the pyrolysis reaction chamber 4, producing high-temperature flue gas carrying ash. The high-temperature flue gas enters the solid-gas inlet of the cyclone separator 6 through the flue gas outlet of the combustion chamber 5. The cyclone separator 6 starts working, using centrifugal force to separate the flue gas from the ash. The separated flue gas is discharged from the flue gas outlet, and the ash is discharged from the solid ash outlet and enters the ash return pipe. The ash cone valve 73 is adjusted so that the ash flow rate entering the first branch 71 is greater than the ash flow rate entering the second branch 72. The ash is then directionally transported to the lower and upper parts of the pyrolysis reaction chamber 4 via the first branch 71 and the second branch 72, respectively. S4: The mixed particles entering the cracking reaction chamber 4 move slowly downwards along the spiral guide plate 13, making full contact with the ash directionally conveyed to the cracking reaction chamber 4 during the movement. The large amount of ash in the lower part of the cracking reaction chamber 4 provides a high-temperature environment and strong catalytic effect, causing the heavy components in the mixed particles to undergo deep co-pyrolysis, and the heavy volatiles are fully released and cracked. The small amount of ash in the upper part of the cracking reaction chamber 4 maintains a moderately low-temperature environment, allowing the light components in the mixed particles to be stably released and avoiding excessive cracking. At the same time, the cracked gas generated by co-pyrolysis flows upwards, forming a counter-current contact with the downward-flowing ash, and continuously undergoing catalytic cracking, deoxygenation, and aromatization reactions. During this process, the circulating fan 15 on the pipeline 10 is started, and the preliminary pyrolysis cracked gas temporarily stored in the pipeline 10 is accelerated through the Laval nozzle 16 and injected into the cracking reaction chamber 4, where it further undergoes a synergistic reaction with the cracked gas and ash generated by co-pyrolysis, promoting hydrogen transfer. S5: The qualified pyrolysis gas generated in the pyrolysis reaction chamber 4 is discharged from the outlet and enters the cooling tower 11 for cooling treatment. After being cooled to room temperature, the pyrolysis gas enters the oil storage tank 12, where the oil phase substances settle and separate to obtain high-purity pyrolysis oil. The product is collected periodically from the oil outlet of the oil storage tank 12. The pyrolysis gas after oil phase separation returns to the combustion chamber 5 through the return pipe 10 at the top of the oil storage tank 12, where it participates in the combustion reaction as auxiliary fuel, continuously providing heat to the system. The high-temperature flue gas separated by the cyclone separator 6 enters the flue gas heating channel of the first screw feeder 1 through the flue gas outlet. After heat exchange with biomass, the temperature decreases, and the cooled flue gas enters the tail gas treatment device 9 through the flue gas outlet. After treatment to meet the standards, it is discharged. The solid residue (carbonaceous material) after the reaction in the pyrolysis reaction chamber 4 continuously falls into the combustion chamber 5, where it is burned together with the recovered pyrolysis gas and auxiliary fuel, continuously generating high-temperature flue gas and ash, ensuring the continuous and stable operation of the system.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A co-pyrolysis system based on ash content control and dynamic encapsulation, characterized in that: include: A biomass feeding unit, the biomass feeding unit including a first screw feeder, the first screw feeder being used to convey uncrushed biomass, the first screw feeder having a flue gas heating channel; The waste plastic feeding unit includes a second screw feeder for conveying uncrushed waste plastic, and the second screw feeder is located below the first screw feeder. A mixing reaction chamber, the inlet of which is connected to the outlet of the first screw feeder and the outlet of the second screw feeder, and the interior of the mixing reaction chamber is provided with a partition, which is located below the outlet of the second screw feeder, and the partition has several openings. The pyrolysis reaction chamber is equipped with a spiral guide plate inside, and the upper end of the pyrolysis reaction chamber is connected to the mixing reaction chamber through two channels respectively. The combustion chamber, cyclone separator, and ash rotary pipe are provided. The combustion chamber is connected to the lower end of the pyrolysis reaction chamber. The inlet of the cyclone separator is connected to the flue gas outlet of the combustion chamber. The solid ash outlet of the cyclone separator is connected to the ash rotary pipe. The ash rotary pipe includes a first branch and a second branch, which are respectively connected to the lower and upper parts of the pyrolysis reaction chamber.

2. The co-pyrolysis system based on ash content control and dynamic encapsulation according to claim 1, characterized in that: The mixing reaction chamber is also equipped with a dispersion device, which is located above the partition.

3. The co-pyrolysis system based on ash content control and dynamic encapsulation according to claim 2, characterized in that: It also includes an exhaust gas treatment device, the inlet of which is connected to the flue gas outlet of the flue gas heating channel, and the flue gas inlet of the flue gas heating channel is connected to the flue gas outlet of the cyclone separator.

4. The co-pyrolysis system based on ash content control and dynamic encapsulation according to claim 1, characterized in that: It also includes a product collection unit, which includes a cooling tower and an oil storage tank. The inlet of the cooling tower is connected to the outlet of the pyrolysis reaction chamber, and the inlet of the oil storage tank is connected to the outlet of the cooling tower.

5. The co-pyrolysis system based on ash content control and dynamic encapsulation according to claim 1, characterized in that: The inlet of the mixing reaction chamber is connected to the outlet of the first screw feeder through a pipeline. A circulating fan and a Laval nozzle are installed on the pipeline. The circulating fan and the Laval nozzle are used to transport the pyrolysis gas in the pipeline and the mixing reaction chamber to the pyrolysis reaction chamber.

6. The co-pyrolysis system based on ash content control and dynamic encapsulation according to claim 1, characterized in that: The ash rotary pipeline is equipped with an ash cone valve, which is used to regulate the ash flow ratio between the first branch and the second branch.

7. A co-pyrolysis method based on ash content control and dynamic encapsulation, characterized in that: Includes the following steps: S1. Biomass pretreatment and preliminary pyrolysis: Uncrushed biomass enters the first screw feeder and undergoes preliminary pyrolysis under the preheating effect of the flue gas heating channel to generate pyrolysis gas and coke particles. S2: Waste plastic feeding and dynamic wrapping: Uncrushed waste plastic enters the second screw feeder and is conveyed to the partition to form a plastic material layer. The coke particles penetrate the plastic material layer under the action of the dispersing device. The plastic material layer is heated and melts and wraps the coke particles to form mixed particles. S3: Ash diversion and directional conveying: The high-temperature flue gas generated in the combustion chamber carries ash into the cyclone separator. The ash is discharged from the solid ash outlet of the cyclone separator and enters the first branch and the second branch. The ash flow rate entering the first branch is greater than the ash flow rate entering the second branch. S4: Staged co-pyrolysis reaction: The mixed particles enter from the top of the pyrolysis reaction chamber and move downward along the spiral guide plate. Under the catalytic action of the ash, a co-pyrolysis reaction occurs and pyrolysis gas is generated. The volatiles in the upward pyrolysis gas come into counter-current contact with the downward ash, and catalytic pyrolysis, deoxygenation and aromatization reactions continue to occur. S5: Product collection and energy recycling: The pyrolysis gas is discharged from the outlet of the pyrolysis reaction chamber, cooled by the cooling tower, and the pyrolysis oil is collected in the oil storage tank. The cooled pyrolysis gas is returned to the combustion chamber. The flue gas separated by the cyclone separator is used to preheat the biomass in the first screw feeder.

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