A large-scale solid heat carrier heating device for organic solid waste pyrolysis process

Abstract

This invention discloses a solid heat carrier heating device, comprising a pyrolysis reactor, a fluidized bed furnace, a gas-solid separator, a mechanical return feeder, and a flue gas generator. The pyrolysis reactor is used to feed solid pyrolysis reactants into the fluidized bed furnace for reaction. The gas-solid separator is used to separate the reaction products in the fluidized bed furnace into gas and solid components to obtain a solid heat carrier, which is then transported to the fluidized bed furnace for reaction via the mechanical return feeder. The flue gas generator is used to supply flue gas into the fluidized bed furnace to heat the solid pyrolysis reactants. This invention also discloses a flue gas generator. The solution of this invention is applicable to the pyrolysis of organic solid wastes such as waste plastics, oil sludge, tires, and sewage sludge. Through efficient combustion and heating methods, the large solid heat carrier furnace achieves high-efficiency pyrolysis carbon combustion, stable bed temperature and bed pressure, and has a function for regulating the flow rate of circulating solid particles.

Description

Technical Field

[0001] This application relates to the technical field of organic solid waste pyrolysis treatment, and in particular to a large-scale solid heat carrier heating device for organic solid waste pyrolysis process. Background Technology

[0002] With the continuous development of global industrialization, waste plastics are increasing daily while fossil fuels are gradually decreasing. Waste plastics are diverse in type, including boxes, bags, ropes, and films, and contain various materials such as PP, PE, PS, PVC, and ABS. These materials are diverse in form, complex in composition, and cannot self-degrade; their incineration pollutes the air more than ordinary materials, making harmless treatment extremely difficult. The pyrolysis-oiling technology for chemical recycling of waste plastics, with its advantage of producing value-added fuels or chemical raw materials, enables the self-circulating resource utilization of plastics from production to recycling, gaining industry acclaim.

[0003] The key conditions for waste plastic pyrolysis to oil production are an oxygen-free environment and a stable and sufficient heat source. By controlling the pyrolysis reaction rate and temperature, thermal decomposition is induced, producing a large amount of pyrolysis oil, along with a certain amount of pyrolysis gas and residual carbon. Currently, waste plastic pyrolysis technology mainly originates from organic solid waste pyrolysis technology, with heating methods concentrated on gaseous heat carriers and solid heat carriers. Among them, solid heat carriers are widely used domestically and internationally due to their advantages such as high heat transfer efficiency and strong integration of pyrolysis equipment. Solid heat carrier pyrolysis technology mainly uses fixed bed, entrained fluidized bed, and circulating fluidized bed technologies. Among these three technologies, circulating fluidized bed technology is the main development direction due to its advantages of strong heat transfer uniformity, fast heat transfer rate, easy coupling with the pyrolysis reactor in the external circulation path, and reuse of the calorific value of pyrolysis products to achieve cogeneration.

[0004] The residual products from the pyrolysis of waste plastics after the extraction of pyrolysis oil are fed into a solid heat carrier furnace, which presents problems such as the difficulty in burning pyrolysis carbon, the failure to meet the bed temperature in the dense phase zone, and the low exit temperature of the solid heat carrier. At the same time, the composition of different types of waste plastics varies greatly, and the content of inorganic matter is different. The particle size deviation entering the solid heat carrier furnace is large, and large inorganic particles are not easy to be discharged from the furnace bed. Long-term operation can easily lead to high bed pressure and even fluidization loss of the bed.

[0005] In addition, the external circulation volume of traditional circulating fluidized bed technology is not adjustable, and the external circulation volume is determined by the internal circulation volume and the amount of ash entering the furnace, so the system is self-balancing. However, in waste plastic pyrolysis technology, the external circulation volume is determined by the amount of waste plastic processed, and the circulation volume gradually increases due to the ash in the waste plastic entering the external circulation system. Therefore, the solid heat carrier furnace must be designed with a reasonable adjustment structure to meet the pyrolysis requirements and the stability of the external circulation system. Summary of the Invention

[0006] This invention provides a pyrolysis-oiling process suitable for organic solid wastes such as waste plastics, oil sludge, tires, and sewage sludge. It utilizes a large-scale industrial heating device that directly combusts some of the pyrolysis products (pyrolysis gas, pyrolysis oil, pyrolysis residual carbon, etc.) of the organic solid waste to heat the quartz sand-type solid heat carrier required for pyrolysis. Through efficient combustion and heating, it ultimately achieves continuous operation of the pyrolysis process system without the need for additional fuel. This enables the large solid heat carrier furnace to achieve high-efficiency pyrolysis carbon combustion, stable bed temperature and pressure, and also provides a function for regulating the flow rate of circulating solid particles.

[0007] In one aspect, a solid heat carrier heating device is provided, including a pyrolysis reactor, a fluidized bed furnace, a gas-solid separator, a mechanical return feeder, and a flue gas generator;

[0008] The pyrolysis reactor is used to feed solid pyrolysis reactants into the fluidized bed furnace for reaction; the gas-solid separator is used to separate the reaction products in the fluidized bed furnace into solids to obtain a solid heat carrier, which is then transported to the fluidized bed furnace for reaction via the mechanical return feeder; the flue gas generator is used to feed flue gas into the fluidized bed furnace to heat the solid pyrolysis reactants.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the pyrolysis reactor is connected between the gas-solid separator and the mechanical return feeder, and the pyrolysis reactor is used to convey the solid heat carrier and the solid pyrolysis reactants to the fluidized bed furnace through the mechanical return feeder;

[0010] The device also includes a dual-leg upper hopper, which includes a control hopper and an overflow hopper. The control hopper is connected between the gas-solid separator and the pyrolysis reactor and is used to deliver solid heat carrier particles to the pyrolysis reactor. The overflow hopper is connected to the fluidized bed furnace and is used to deliver solid heat carrier particles overflowing from the control hopper to the fluidized bed furnace.

[0011] In conjunction with the first aspect, in certain implementations of the first aspect, the dual-leg upper hopper satisfies at least one of the following:

[0012] The lower end of the overflow bin has a U-shaped material return structure;

[0013] The distance between the return port connecting the overflow chamber and the fluidized bed furnace and the air distribution plate inside the fluidized bed furnace is 1-2m;

[0014] In scenarios where there is no chlorine-free waste plastics, oil sludge, tires, or sewage sludge, the control chamber and the pyrolysis reactor are connected by a single path.

[0015] In the case of chlorine-containing plastics, the control chamber and the pyrolysis reactor are connected by multiple paths.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the fluidized bed furnace is provided with a multi-stage trapezoidal platform, the multi-stage trapezoidal platform being located in the height direction between the flue gas generator and the mechanical return feeder, and the inner diameter of the lower step surface of the multi-stage trapezoidal platform being smaller than the area of ​​the upper step surface of the multi-stage trapezoidal platform.

[0017] In conjunction with the first aspect, in certain implementations of the first aspect, the multi-stage trapezoidal platform satisfies at least one of the following:

[0018] The area of ​​the lowest step surface is 35%-50% of the cross-sectional area of ​​the dilute phase region of the fluidized bed furnace;

[0019] The height between two adjacent steps is 0.2-0.4m;

[0020] The area of ​​the upper step is 10-30% larger than that of the lower step.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the fluidized bed furnace is provided with multi-layer sidewall burners, the multi-layer sidewall burners and the mechanical return feeder are arranged opposite to each other, each layer of sidewall burners is multiple and is arranged symmetrically or circumferentially uniformly, and each sidewall burner is inclined downward at 5-30°.

[0022] In conjunction with the first aspect, in certain implementations of the first aspect, the multi-layer sidewall burner satisfies any one of the following:

[0023] The multi-layer sidewall burner has three layers. The first layer of sidewall burners is installed at a height of 1.5-2.5m, the second layer of sidewall burners is installed at a height of 2.6-3.5m, and the third layer of sidewall burners is installed at a height of 3.6m or more. The downward tilt angle of the first layer of sidewall burners is α1, the downward tilt angle of the second layer of sidewall burners is α2, and the downward tilt angle of the third layer of sidewall burners is α3, where α1≥α2≥α3.

[0024] The multi-layer sidewall burner has two layers. The first layer of sidewall burner is installed at a height of 2.6-3.5m, and the second layer of sidewall burner is installed at a height of 3.6m or more. The downward tilt angle of the first layer of sidewall burner is α2, and the downward tilt angle of the second layer of sidewall burner is α3, where α2 ≥ α3.

[0025] The multi-layer sidewall burner has two layers. The first layer of sidewall burner is installed at a height of 1.5-2.5m, and the second layer of sidewall burner is installed at a height of 2.6-3.5m. The downward tilt angle of the first layer of sidewall burner is α1, and the downward tilt angle of the second layer of sidewall burner is α2, where α1≥α2.

[0026] The multi-layer sidewall burner has two layers. The first layer of sidewall burner is installed at a height of 1.5-2.5m, and the second layer of sidewall burner is installed at a height of 3.6m or more. The downward tilt angle of the first layer of sidewall burner is α1, and the downward tilt angle of the second layer of sidewall burner is α3, where α1≤α3.

[0027] In conjunction with the first aspect, in some implementations of the first aspect, the dilute phase zone of the fluidized bed furnace is provided with a tertiary air inlet, through which tertiary air is injected into the fluidized bed furnace at a tangential angle β, where 0°≤β≤75°.

[0028] In conjunction with the first aspect, in some implementations of the first aspect, the apparatus further includes:

[0029] The flue gas separated by the gas-solid separator enters the settling heat exchange channel through the burnout insulation channel. The burnout insulation channel is a descending channel for the flue gas, and the settling heat exchange channel is an ascending channel for the flue gas. Baffles are provided at the connection between the burnout insulation channel and the settling heat exchange channel. Both the burnout insulation channel and the settling heat exchange channel are equipped with figure-eight baffles.

[0030] In conjunction with the first aspect, in some implementations of the first aspect, the flue gas generator includes:

[0031] A combustion chamber and a secondary air porous distribution structure, wherein the secondary air porous distribution structure is disposed in the combustion chamber, dividing the combustion chamber into an inner cavity and an outer cavity, and the inner cavity and the outer cavity are connected by through holes in the secondary air porous distribution structure;

[0032] The burner housing is in communication with the combustion chamber cavity;

[0033] The combustion air inlet is located in the burner housing and includes a first combustion air passage and a second combustion air passage. The first combustion air passage enters the combustion chamber through the burner housing to achieve an excess air coefficient of 0.6-0.9. The second combustion air passage is connected to the outer cavity of the combustion chamber.

[0034] The secondary air porous distribution structure has a first-stage air inlet, which is located on the side of the secondary air porous distribution structure close to the burner housing. The first-stage air inlet and the first combustion air channel are superimposed to achieve an excess air coefficient of 1.0-1.5.

[0035] Secondly, a flue gas generator is provided, comprising:

[0036] A combustion chamber and a secondary air porous distribution structure, wherein the secondary air porous distribution structure is disposed in the combustion chamber, dividing the combustion chamber into an inner cavity and an outer cavity, and the inner cavity and the outer cavity are connected by through holes in the secondary air porous distribution structure;

[0037] The burner housing is in communication with the combustion chamber cavity;

[0038] The combustion air inlet is located in the burner housing and includes a first combustion air passage and a second combustion air passage. The first combustion air passage enters the combustion chamber through the burner housing to achieve an excess air coefficient of 0.6-0.9. The second combustion air passage is connected to the outer cavity of the combustion chamber.

[0039] The secondary air porous distribution structure has a first-stage air inlet, which is located on the side of the secondary air porous distribution structure close to the burner housing. The first-stage air inlet and the first combustion air channel are superimposed to achieve an excess air coefficient of 1.0-1.5.

[0040] In conjunction with the second aspect, in some implementations of the second aspect, the secondary air porous distribution structure further has a second-stage air inlet, which is located on the side of the secondary air porous distribution structure away from the burner housing. The first combustion air channel, the first-stage air inlet, and the second-stage air inlet are superimposed to achieve an excess air coefficient of 3-4.

[0041] In conjunction with the second aspect, in some implementations of the second aspect, the first-stage air inlet is arranged in a single row with a quantity of 12-60, the second-stage air inlet is arranged in multiple rows with a quantity of 24-120, and the area ratio of the second-stage air inlet to the first-stage air inlet is 2-6.

[0042] In conjunction with the second aspect, in some implementations of the second aspect, the burner housing is further provided with a central fuel gun, which extends into the burner housing for delivering auxiliary fuel into the combustion chamber.

[0043] A circumferential gas collector surrounds the outer periphery of the central fuel gun and has multiple circumferential gas guns evenly fixed thereon. One end of each circumferential gas gun is fixed to the circumferential gas collector and fits against the inner wall of the combustion chamber, for delivering pyrolysis gas into the combustion chamber.

[0044] In conjunction with the second aspect, in some implementations of the second aspect, the number of the plurality of circumferential gas guns is 3-18.

[0045] Thirdly, a solid heat carrier heating device is provided, including a flue gas generator as described in any of the implementations of the second aspect above.

[0046] Compared with the prior art, the solution provided in this application includes at least the following beneficial technical effects.

[0047] In this invention, a portion of the pyrolysis gas (pyrolysis oil) and pyrolysis residue carbon from organic solid waste such as waste plastics, oil sludge, sewage sludge, and tires enters the burner of the device, directly heating the sand-like solid heat carrier and the pyrolysis residues of the waste inside the furnace. This achieves rapid heating of the solid heat carrier and efficient combustion of combustible substances in the pyrolysis residues of waste plastics, oil sludge, and tires. A portion of the heated solid heat carrier is directly mixed and stirred with the waste plastics and oil sludge in the reactor for heat exchange, directly heating and pyrolyzing the waste plastics and oil sludge, ultimately achieving continuous operation of the pyrolysis process system without additional fuel. Another portion directly enters the dense phase zone at the bottom of the furnace, heating the circulating fluidized bed and improving the combustion rate of pyrolysis residue carbon. This heating device can control and adjust the circulation volume of the solid heat carrier, ensuring stable bed pressure, uniform furnace temperature, high combustion efficiency, low NOx and CO emissions, and significantly lower fly ash emissions than conventional methods. It guarantees stable bed temperature and pressure inside the furnace and has an external circulating ash volume adjustment function, making it a large-scale, industrially applicable solid heat carrier heating furnace.

[0048] This patent addresses the problem of difficult combustion of pyrolytic carbon in the residue after pyrolysis of organic solid waste. It employs a cyclone separator with a double-leg feed hopper at the bottom, directly feeding some high-temperature solid particles into the dense phase zone at the bottom of the furnace. This increases the temperature in the dense phase zone, thereby increasing the combustion rate of pyrolytic carbon and improving combustion efficiency. Simultaneously, the conventional fluidized bed primary fluidizing air is replaced with high-temperature flue gas, and multi-layer sidewall burners are added to rapidly increase the temperature of the pyrolysis residue and further enhance the combustion rate of pyrolytic carbon. The multi-layer sidewall burners can also be modified to use gas injection pipes in the dense phase zone for supplementary combustion heating. A swirl tertiary air inlet is added to increase the residence time in the furnace, thus increasing the combustion reaction time. A burnout insulation channel is provided at the rear end, which maintains the high-temperature flue gas temperature. A supplementary combustion burner is installed in this channel to further increase the flue gas temperature when needed. The fine particles of the pyrolysis residue can further burn the residual carbon in the high-temperature environment, reducing the carbon content of the fly ash, and also burning CO in the flue gas, thereby improving combustion efficiency. Meanwhile, by designing the bottom structure of the furnace wall, the residence time of pyrolytic carbon in the dense phase zone at the bottom of the furnace is increased, and the combustion share of pyrolytic carbon in the dense phase zone is increased, thereby reducing the carbon content of fly ash generated in the furnace and increasing the temperature of the dense phase bed.

[0049] This patent addresses the issue of fine ash from organic solid wastes such as oil sludge and sewage sludge, which can easily affect the overall ash balance. It innovatively designs a combined silo structure with an overflow mechanism, achieving highly reliable mechanical distribution of ash flow at high temperatures. This silo structure is a double-leg upper silo below the cyclone separator. Solid heat carrier particles first fall into one silo (control silo). Once the height exceeds the partition between the two silos, they gradually overflow into the other silo (overflow silo). The control silo is equipped with a discharge controller and level gauge to adjust the particle accumulation height within the ash silo, ensuring a certain level and achieving upper ash silo sealing to prevent air from entering the reactor, while also controlling the circulating particle flow rate. Controlling the accumulation height in this path allows excess solid particles to overflow directly into the adjacent overflow silo, and then be fed into the furnace through a return feeder below the overflow silo. This prevents excessive solid heat carrier from entering the reactor, ensuring the reactor's reaction temperature, maintaining ash balance in the fluidized bed furnace, increasing the temperature in the dense phase zone, and avoiding additional slag discharge that could reduce furnace thermal efficiency. Ash discharge ports are provided above the upper silo, intermediate silo, and dense phase zone of the fluidized bed furnace to discharge excess circulating ash and ensure the overall single-loop ash balance of the fluidized bed furnace.

[0050] This patent addresses the problem of easy clogging caused by fine ash from organic solid wastes such as oil sludge and sewage sludge. A burnout insulation channel and a heat exchange settling channel are installed at the rear of the device. The channels are equipped with V-shaped baffles and baffles at the bottom to settle the easily agglomerated parts of the fly ash, preventing clogging of the downstream waste heat recovery device. Simultaneously, the heat exchange settling channel is equipped with heat exchange tubes to rapidly reduce the flue gas temperature and flow rate, improving the gravity settling effect of the fly ash. The rapid reduction in flue gas temperature ensures it is well below the softening temperature of the fly ash, preventing fly ash containing alkali metals from adhering to the downstream waste heat boiler device.

[0051] This patent addresses the problem of poor combustion stability in under-bed burners with high excess air coefficients. Combustion of pyrolysis gas or oil generates high-temperature flue gas at 550-1000℃, requiring an excess air coefficient of 2.5-5.1. A high excess air coefficient easily leads to combustion instability issues such as flame drift, incomplete combustion, combustion vibration, secondary combustion, and flameout. By employing a specially designed air-staged burner, the excess air coefficient in the central combustion is controlled at 0.6-0.9. Due to diffusion combustion, this achieves both stable combustion and reduced thermal NOx generation. The remaining air is injected in stages through the burner's secondary air duct. A swirler is located at the center, creating swirling combustion. The swirling flame and secondary air can mix relatively quickly, enabling rapid combustion and mixing within the limited combustion chamber, resulting in high-temperature flue gas with a uniform temperature field. This stable combustion structure also ensures a stable fluidized bed and good fluidization effect.

[0052] This patent addresses the problem of ash overheating and slagging in the furnace under heavy load on the bed burner by employing a multi-layered sidewall tube group gas burner, with the sidewall burners tilted downwards at 5-15°. The tube group combustion organization of the burners features good combustion stability and a short flame, ensuring near-complete combustion at the burner outlet and avoiding the influence of fluidized suspended particles on combustion. The 5-15° downward tilt effectively heats the particles in the dense phase zone, thereby improving the combustion efficiency of organic solid waste pyrolysis carbon in the dense phase zone, while preventing suspended particles falling along the wall from clogging the burner. The burners in the same layer are either counter-rotating or circumferentially distributed to ensure uniform heating. The tilt angle of the lower burners is generally greater than that of the upper burners. This multi-layered sidewall burner setup with different angles avoids the problem of concentrated combustion areas and the tendency for ash particles in the furnace to soften and slag at high temperatures. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the solid heat carrier furnace of the present invention.

[0054] Figure 2 This is a schematic diagram of the multi-layer sidewall burner distribution.

[0055] Figure 3 A schematic diagram of the three-stage air duct setup.

[0056] Figure 4 This is a schematic diagram of a bottom-stage combustion low-NOx high-temperature flue gas generator.

[0057] In the diagram: 1 Bottom-stage combustion low-NOx high-temperature flue gas generator; 2 Multi-layer sidewall burner; 3 Mechanical return feeder; 4 Intermediate silo; 5 Pyrolysis reactor; 6 Feed controller; 7 Double-leg upper silo; 8 Cyclone gas-solid separator; 9 Fluidized bed furnace; 10 Tertiary air outlet; 11 Supplementary combustion burner; 12 Burnout insulation channel; 13 Figure-eight baffle; 14 Settling heat exchange channel; 15 Waste heat recovery section; 16 Burner shell; 17 Central fuel gun; 18 Circumferential gas collector; 19 Combustion air inlet; 20 Circumferential gas gun; 21 Cyclone separator; 22 Bottom combustion chamber; 23 Secondary air porous distribution structure. Detailed Implementation

[0058] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0059] Figure 1 This is a schematic structural diagram of a solid heat carrier device for solid waste pyrolysis treatment provided in an embodiment of this application.

[0060] The solid heat carrier furnace may include a bottom-stage combustion low-NOx high-temperature flue gas generator 1; a multi-layer sidewall burner 2; a mechanical return feeder 3; an intermediate silo 4; a pyrolysis reactor 5; a feeding controller 6; a double-leg upper silo 7; a cyclone gas-solid separator 8; a fluidized bed furnace 9; a tertiary air outlet 10; a supplementary combustion burner 11; a burnout insulation channel 12; a figure-eight baffle 13; a settling heat exchange channel 14; and a waste heat recovery section 15.

[0061] A high-temperature flue gas generator 1 is located at the bottom of the fluidized bed furnace 9, providing high-temperature flue gas of 500-1000°C into the fluidized bed furnace 9. The high-temperature flue gas can be material fluidizing air. In some embodiments, the bottom of the fluidized bed furnace 9 is in a dense phase zone, which is less than 2 meters from the air distribution plate. In the dense phase zone, a high-temperature and wear-resistant lining can be installed around the inner wall of the fluidized bed furnace 9 facing the fire, thereby improving the service life of the lining; water-cooling pipes can be installed on the outside of the lining.

[0062] The mechanical return feeder 3 is connected to the lower part of the fluidized bed furnace 9, and the connection point between the mechanical return feeder 3 and the fluidized bed furnace 9 can be located above the high-temperature flue gas generator 1. The mechanical return feeder 3 can feed the pyrolysis residue of organic solid waste and solid heat carrier into the fluidized bed furnace 9. The high-temperature flue gas supplied by the high-temperature flue gas generator 1 can fluidize and heat the materials and bed material. The solid heat carrier supplied by the mechanical return feeder 3 can originate from the pyrolysis reactor 5, and the pyrolysis residue of organic solid waste supplied by the mechanical return feeder 3 also includes substances that were not completely burned in the fluidized bed furnace 9 in the previous cycle.

[0063] The gas-solid mixed phase outlet at the top of the fluidized bed furnace 9 can be connected to the cyclone gas-solid separator 8. Solid heat carrier particles and some small particles (diameter ≤300µm) and other pyrolysis reactants are carried out of the fluidized bed furnace 9 by the fluidized flue gas and enter the cyclone gas-solid separator 8 for gas-solid separation. The bottom of the cyclone gas-solid separator 8 is connected to the upper hopper 7 with dual-legs, ensuring that most particles are captured and enter the upper hopper 7. In some embodiments, the upper hopper 7 with dual-legs is equipped with an ash discharge port to discharge excess ash, addressing the problem of numerous fine organic solid waste particles easily affecting the overall ash balance.

[0064] In some embodiments provided in this application, the dual-leg upper hopper 7 may have two hopper structures. Solid heat carrier particles first fall into one of the hoppers (control hopper). When the accumulated height of the solid heat carrier particles exceeds the separation between the two hoppers, the solid heat carrier particles can gradually slide into the other hopper (overflow hopper). The aforementioned ash discharge port may, for example, be located in the control hopper.

[0065] The overflow chamber has a return structure at its lower end, which can send excess solid particles overflowing into the lower part of the fluidized bed furnace 9. Figure 1In the illustrated embodiment, the return structure can be U-shaped. This enables high-rate circulation, effectively increasing the temperature in the dense phase zone, improving combustion efficiency, preventing excessive solid heat carrier from entering the reactor, ensuring the reactor's reaction temperature and the ash balance in the fluidized furnace, and preventing a decrease in furnace thermal efficiency.

[0066] In some embodiments, the distance between the return port connecting the overflow chamber and the fluidized bed furnace 9 and the bottom air distribution plate is 1-2m, so as to facilitate heating the dense phase zone of the fluidized bed furnace 9.

[0067] The lower end of the control chamber can be connected to the feed controller 6. The feed controller 6 can be used to adjust the mass flow rate of the particles discharged from the control chamber, while ensuring that the particles in the control chamber accumulate at a certain material level, realizing the sealing of the upper ash hopper, preventing air from entering the reactor, and also obtaining the circulating particle flow rate to realize the flow measurement function.

[0068] The lower end of the feed controller 6 is connected to the solid heat carrier inlet channel of the pyrolysis reactor 5. Through the adjustment of the feed controller 6, the solid heat carrier enters the pyrolysis reactor 5 at the designed flow rate. The pyrolysis reactor 5 is equipped with inlets for both the solid heat carrier and organic solid waste. The pretreated organic solid waste and solid heat carrier are stirred and heat exchanged within the reactor. The organic solid waste is rapidly heated to the pyrolysis reaction temperature, generating pyrolysis gas and gaseous pyrolysis oil. The gaseous pyrolysis products are discharged and collected through the reactor inlet for further processing.

[0069] The organic solid waste entering pyrolysis reactor 5 from another material inlet undergoes stirring and heat exchange. Depending on the type of waste plastic, pyrolysis reactor 5 can adopt a rapid drying pyrolysis structure or a segmented structure. After being heated by a solid heat carrier, the organic solid waste undergoes a pyrolysis reaction, and the generated gaseous pyrolysis oil and pyrolysis gas are discharged from the pyrolysis product outlet of pyrolysis reactor 5 into the subsequent purification treatment system.

[0070] In some embodiments, the solid heat carrier can enter the pyrolysis reactor 5 through the upper hopper 7 via a single or multiple channels, with the specific number of channels matching the function of the pyrolysis reactor 5. A single channel entering the pyrolysis reactor 5 can be used to treat chlorine-free waste plastics such as PP, PE, and PS, as well as chlorine-free organic solid wastes such as sludge, tires, and sewage sludge. When the waste plastics contain chlorine-containing components such as PVC, the solid heat carrier flow regulation device can employ a scheme with two or more channels. Along the functional area of ​​the pyrolysis reactor 5, a first channel is set for melting and dechlorinating the waste plastics, and a second channel is set for rapidly heating and pyrolyzing the melted waste plastics, wherein the flow rate of the first channel is less than the flow rate of the second channel.

[0071] In some embodiments, the pyrolysis reactor 5 can adopt a horizontal structure, and its internal structure can employ either single-inlet pyrolysis or multi-inlet pyrolysis with a solid heat carrier, depending on the pyrolysis requirements of the waste plastics. According to the circulation scheme, the pyrolysis reactor 5 can adopt a segmented structure consisting of an integrated drying and pyrolysis functional area, a pre-drying melting and dechlorination area, and a post-pyrolysis area. The pyrolysis reactor 5 can also adopt an integrated structure comprising a solid heat carrier feed sealing section, a drying and pyrolysis functional area, and an outlet sealing + return structure.

[0072] The lower outlet of the pyrolysis reactor 5 can be connected to the flange of the intermediate silo 4. The pyrolysis residue and the solid heat carrier that has undergone heat exchange are discharged from the pyrolysis reactor 5 and enter the intermediate silo 4.

[0073] In some embodiments, the intermediate silo 4 is equipped with a level gauge to control the material level within the silo 4, ensuring material sealing and preventing backflow of flue gas from the furnace into the pyrolysis reactor 5. Simultaneously, the organic solid waste pyrolysis reactants can continue to react within the intermediate silo 4. The intermediate silo 4 may be equipped with a gaseous pyrolysis product conveying pipe for continued collection of pyrolysis gas and gaseous pyrolysis oil.

[0074] In some embodiments, the intermediate silo 4 is equipped with an ash discharge port, which, in addition to discharging excess ash, can also provide emergency discharge when the material exceeds the set material level alarm height. This solves the problem that a large number of fine particles in organic solid waste can easily affect the overall ash balance.

[0075] The outlet of intermediate silo 4 is connected to the inlet flange of mechanical return feeder 3. The mixed material is buffered in intermediate silo 4 before entering mechanical return feeder 3. The outlet of mechanical return feeder 3 is connected to the return inlet flange of fluidized bed furnace 9. The material entering fluidized bed furnace 9 is pyrolyzed organic solid waste and solid heat carrier. After the pyrolysis reaction, the material temperature drops to 400-600℃. At this time, the material needs to enter the furnace for direct heating to 750-1000℃. After heating, the pyrolysis residue carbon and other combustible components in the organic solid waste will be further burned, while the quartz sand-like solid heat carrier will be reheated.

[0076] In some embodiments, the distance between the return inlet of the mechanical return device 3 connected to the fluidized bed furnace 9 and the bottom air distribution plate is 1-2m.

[0077] In some embodiments, the mechanical return feeder 3 can adopt a high-temperature screw conveyor structure, and the conveying amount of the mixed materials can be adjusted by using motor frequency control. The material adjustment loop control is mainly achieved by the return amount, the internal circulation amount of the furnace, and the solid heat carrier flow rate adjustment device.

[0078] The gas-solid two-phase mixture enters the high-temperature gas-solid cyclone separator 8 from the outlet of the fluidized bed furnace 9. In the gas-solid separator 8, the solid heat carrier is recovered and the large suspended particles of organic solid waste are captured. The large suspended particles of organic solid waste can be recycled as a supplement to the solid heat carrier, and the unburned pyrolysis carbon can be recycled for re-combustion, reducing energy loss.

[0079] In some embodiments provided in this application, the fluidized bed furnace 9 is equipped with an air distribution plate. Above the air distribution plate are the dense phase combustion zone, the transition zone, and the dilute phase zone, with the gas-solid mixed phase outlet at the top. Depending on the scale of waste plastic processing, the fluidized bed furnace can adopt a fully insulated structure or a lower insulated + upper water-cooled wall structure. With a fully insulated structure, the furnace temperature is adjusted by varying the airflow with different excess air coefficients to ensure the gas-solid phase outlet temperature meets pyrolysis requirements. For large-scale processing, a fully insulated + upper water-cooled wall structure is used, with the water-cooled wall located at the gas-solid mixed phase outlet to ensure both gas and solid phase outlet temperatures meet pyrolysis requirements.

[0080] In some embodiments, a gas hood can be installed on the upper part of the air distribution plate. A gas pipeline is connected to the gas hood through the bottom air chamber. Gas is injected into the bottom of the dense phase zone through the gas pipeline and mixed with the air above the bed. The gas is then directly combusted in the dense phase zone to heat the bed and increase the temperature of the dense phase zone.

[0081] In some embodiments provided in this application, the bottom of the fluidized bed furnace 9 is provided with an ash discharge port, which can discharge some of the fluidized particulate matter, adjust the bed height and bed pressure, and solve the problem that a large number of fine organic solid waste particles can easily affect the overall ash balance.

[0082] In some embodiments provided in this application, the bottom of the fluidized bed furnace 9 can be provided with a multi-stage trapezoidal platform, located between the connection position of the fluidized bed furnace 9 and the connection position of the fluidized bed furnace 9 and the mechanical return feeder 3. The inner diameter of the lower step surface can be smaller than the area of ​​the upper step surface. The multi-stage trapezoidal platform is generally designed with 2-3 steps. The lowest step has the smallest area and the highest flow velocity, effectively avoiding the adverse situation of coking and slagging at the bottom during the fluidization of organic solid waste. As the number of steps increases, the flow area gradually expands, the particle velocity decreases, and the combustion efficiency is further improved.

[0083] The structure of the multi-stage trapezoidal platform can be determined based on the pyrolytic carbon particle size distribution curve, the proportion of pyrolytic carbon in the mixture of solid heat carrier and pyrolysis residue, and the ignition point and combustion rate of pyrolytic carbon. A well-designed multi-stage trapezoidal platform structure is beneficial for increasing the residence time of pyrolytic carbon in the dense phase region, increasing the combustion share of pyrolytic carbon in the dense phase region, and reducing the proportion of pyrolytic carbon entering the dilute phase region of the furnace, thereby reducing the carbon content of fly ash generated in the furnace and increasing the temperature of the dense phase bed. In some embodiments, the area of ​​the lowest layer of the multi-stage trapezoidal platform is 35%-50% of the cross-sectional area of ​​the dilute phase region of the fluidized bed. Each subsequent step has a height of 0.2-0.4 m, and the cross-sectional area of ​​the upper step is 10-30% larger than that of the lower step.

[0084] In some embodiments provided in this application, a multi-layer sidewall burner 2 is disposed at the lower part of the fluidized bed furnace 9. Thus, the solid heat carrier particles are heated and fluidized within the furnace by the high-temperature flue gas at the bottom and the multi-layer sidewall burner, and the pyrolysis reactants are also heated within the furnace, further fluidizing and burning. The sidewall gas burner 2 can employ an ultra-short flame rapid combustion or flameless combustion organization method, ensuring that combustion is essentially complete by the time the burner enters the furnace from the combustion chamber outlet, thus avoiding the influence of fluidized particles on combustion within the furnace. In some embodiments, the sidewall gas burner 2 can be disposed in the dense phase zone or transition zone of the fluidized bed furnace 9.

[0085] exist Figure 1 In the illustrated embodiment, the multi-layer sidewall burner 2 is positioned at a height similar to that of the mechanical return feeder 3 on the fluidized bed furnace 9; that is, the multi-layer sidewall burner 2 and the mechanical return feeder 3 are arranged opposite each other. The multi-layer sidewall burner 2 and the mechanical return feeder 3 are located on different sides of the fluidized bed furnace 9. The multi-layer sidewall burner 2 comprises at least two layers of sidewall burners. Each layer contains multiple sidewall burners, arranged symmetrically or circumferentially to ensure heating uniformity. Each sidewall burner may, for example, be tilted downwards by 5-30°.

[0086] The multi-layer sidewall burner 2 heats both the solid heat carrier and the pyrolysis residue, thereby improving the combustion efficiency of the pyrolysis carbon. The pyrolysis carbon from the organic solid waste pyrolysis residue is heated to its ignition point within the fluidized bed furnace 9 and undergoes a combustion reaction. The multi-layer sidewall burner 2 is adjusted according to the combustion status of the pyrolysis carbon in the material, ultimately ensuring that the temperature of the flue gas and fluidized solid particles reaches the design temperature at the outlet of the fluidized bed furnace 9. The typical outlet temperature is 750-1000℃, depending on process requirements.

[0087] Figure 2 A schematic structural diagram of a multi-layer sidewall burner 2 is shown. Figure 2In the illustrated embodiment, the multi-layer sidewall burner 2 has three layers. The bottommost sidewall burner is installed at a height of 1.5-2.5m, the next next lowest sidewall burner at a height of 2.6-3.5m, and the topmost sidewall burner at a height of 3.6m or more. This height is the distance from the center of the sidewall burner to the air distribution plate at the bottom of the furnace. The downward tilt angle of the bottommost sidewall burner is α1, the downward tilt angle of the next next lowest sidewall burner is α2, and the downward tilt angle of the topmost sidewall burner is α3, where α1 ≥ α2 ≥ α3.

[0088] In another embodiment, the multi-layer sidewall burner 2 has two layers. The first layer of sidewall burners is installed at a height of 2.6-3.5m (corresponding to the lowermost sidewall burner mentioned above), and the second layer of sidewall burners is installed at a height of 3.6m or more (corresponding to the uppermost sidewall burner mentioned above). The downward tilt angle of the first layer of sidewall burners is α2, and the downward tilt angle of the second layer of sidewall burners is α3, where α2 ≥ α3.

[0089] In another embodiment, the multi-layer sidewall burner 2 has two layers. The height of the top layer sidewall burner is 1.5-2.5m (corresponding to the bottommost sidewall burner mentioned above), and the height of the second layer sidewall burner is 2.6-3.5m (corresponding to the next lowermost sidewall burner mentioned above). The downward tilt angle of the first layer sidewall burner is α1, and the downward tilt angle of the second layer sidewall burner is α2, where α1 ≥ α2.

[0090] This is because the particle concentration inside the furnace is inversely proportional to the furnace height by a power law. A lower furnace height results in a higher particle concentration, requiring a larger burner inclination angle to prevent fluidized particles from entering the burner and affecting combustion. At the same time, as the height increases, the inclination angle decreases, which can also prevent the flames of the upper burner and the next lower burner from overlapping, forming localized high-temperature zones that cause coking of particles inside the furnace.

[0091] In another embodiment, the multi-layer sidewall burner 2 has two layers. The height of the top layer sidewall burner is 1.5-2.5m (corresponding to the bottommost sidewall burner mentioned above), and the height of the second layer sidewall burner is 3.6m or more (corresponding to the topmost sidewall burner mentioned above). The downward tilt angle of the first layer sidewall burner is α1, and the downward tilt angle of the second layer sidewall burner is α3, where α1 ≤ α3.

[0092] Because sidewall burners have low efficiency in heating the dense phase region, their heating efficiency decreases significantly as the burner position increases. With only the top and bottom burners, the tilt angle can be appropriately increased to improve the heating efficiency of the top sidewall burner. Simultaneously, the distance between the top and bottom sidewall burners is relatively large, so even if the tilt angle of the upper burner increases, it will not overlap with the flame of the lower burner.

[0093] The lower burner primarily heats the dense phase region, while the upper burner mainly heats the upper layer or transition zone of the dense phase region. The multi-layered sidewall burner configuration at different angles avoids concentrated combustion zones, preventing the high-temperature softening and slagging of particulate matter. This sidewall combustion supplementary combustion method further increases the furnace temperature and improves the burnout rate of residual combustibles from pyrolysis, while simultaneously heating the solid heat carrier.

[0094] The sidewall burner load can be adjusted according to the combustion of pyrolytic carbon in the material to ultimately ensure that the flue gas and fluidized solid particles temperature reaches 750-1000℃. Under normal operating conditions, the sidewall load accounts for approximately 40%-70% of the overall load.

[0095] In some embodiments, the aforementioned sidewall burner can be replaced with a gas nozzle for supplementary combustion heating. The nozzles are positioned with inlets in the dense phase region, typically evenly distributed circumferentially; for example, one inlet is usually placed every 0.3 meters. Based on this principle, the multi-layer burner configuration can be extended to four layers or even more. For example, the lowermost sidewall burner can be replaced with two layers of gas nozzles, thus extending the multi-layer burner configuration to four layers.

[0096] In some embodiments provided in this application, the tertiary tuyer 10 is installed in the middle or upper middle part (dilute phase zone) of the fluidized bed furnace 9. In some embodiments, the tertiary tuyer 10 may be located above the multi-layer sidewall burner 2. The installation height of the tertiary tuyer 10 in the fluidized bed furnace 9 may be aligned with the connection height between the overflow chamber of the double-leg upper hopper 7 and the fluidized bed furnace 9. Specific settings are as follows: Figure 3 As shown.

[0097] In some embodiments, tertiary air is injected into the furnace at a certain tangential angle β (0°≤β≤75°), which drives the flue gas in the furnace to generate swirl, thereby increasing the residence time of fluidized particulate matter in the furnace and facilitating further combustion of residual carbon from the pyrolysis of organic solid waste in the furnace. The injection of tertiary air can also regulate the furnace temperature field, NOx and CO emissions.

[0098] In some embodiments provided in this application, an insulated furnace or water-cooled wall structure can be provided on the four walls of the dilute phase zone of the fluidized bed furnace 9, based on the calorific value of the pyrolysis gas and carbon generated from the pyrolysis of waste plastics. When the calorific value of the gas and carbon is high, water-cooled walls are provided on the four walls to adjust the outlet temperature of the gas-solid two-phase system to meet the pyrolysis requirements, so that after the fuel is heated in the solid heat carrier furnace, the excess heat is used to generate steam, realizing cogeneration of heat and gas.

[0099] As described above, the gas-solid mixture outlet at the top of the fluidized bed furnace 9 can be connected to a cyclone gas-solid separator 8. Solid particles and flue gas carried out by the fluidization process enter the cyclone gas-solid separator 8 for gas-solid separation. The upper end of the cyclone gas-solid separator 8 is connected to a burnout insulation channel 12, and the separated fine particles and flue gas enter the burnout insulation channel 12 from the upper end. Figure 1 In the illustrated embodiment, the burnout insulation channel 12 is located on one side of the fluidized bed furnace 9 and can be arranged parallel to the fluidized bed furnace 9. The burnout insulation channel 12 can be a descending channel for flue gas. The insulation properties of the burnout insulation channel 12 can maintain the temperature of the high-temperature flue gas.

[0100] Fine particles and flue gas entering the burnout insulation channel 12 can undergo further combustion within the channel. Specifically, CO in the flue gas and residual pyrolytic carbon within the particles can be further burned, causing some fine particles to settle. A supplementary combustion burner 11 is installed at the top of the channel, which can further increase the flue gas temperature when needed, thereby further burning the residual pyrolytic carbon in the fine ash in a high-temperature environment, reducing the carbon content of the fly ash, and simultaneously burning CO in the flue gas to improve combustion efficiency.

[0101] The rear end of the burnout insulation channel 12 is connected to the front end of the settling heat exchange channel 14. Flue gas enters the settling heat exchange channel 14, where some fine particles settle and some of the waste heat is recovered. The settling heat exchange channel 14 can also be a rising channel for the flue gas.

[0102] exist Figure 1 In the illustrated embodiment, baffles are provided at the connection point between the rear end of the burnout insulation channel 12 and the front end of the settling heat exchange channel 14. This allows some fly ash to settle down through inertia and gravity, particularly the portion of fly ash that is prone to clumping, preventing clogging of the downstream waste heat recovery device. Both the burnout insulation channel 12 and the settling heat exchange channel 14 are equipped with V-shaped baffles 13 to further enhance dust removal efficiency. When flue gas enters the settling heat exchange channel 14, the heat exchange tubes rapidly reduce the flue gas temperature and flow rate, improving the gravity settling effect of fly ash. Simultaneously, the rapid reduction in flue gas temperature keeps it well below the fly ash softening temperature, preventing fly ash containing alkali metals from adhering to the downstream waste heat boiler device.

[0103] The rear end of the settling heat exchange channel 14 is connected to the waste heat recovery section 15. After entering the waste heat recovery section 15, the flue gas further recovers its waste heat, improving energy efficiency. Finally, the flue gas is discharged into the flue gas purification system to achieve compliant emissions. In some embodiments, after entering the waste heat recovery section 15, the waste heat can be recovered through a waste heat boiler and an air preheater.

[0104] In some embodiments, the high-temperature flue gas generator 1 can employ a staged air combustion method to burn pyrolysis gas or pyrolysis oil to generate high-temperature flue gas at 550-1000°C, with an excess air coefficient of 2.5-5.1. A high excess air coefficient can easily lead to combustion instability problems such as flame drift, incomplete combustion, combustion vibration, secondary combustion, and flameout. Therefore, this application embodiment also provides a bottom-staged combustion low-NOx high-temperature flue gas generator.

[0105] Figure 4 This is a schematic structural diagram of a bottom-stage combustion low-NOx high-temperature flue gas generator provided in an embodiment of this application. The high-temperature flue gas generator may include a burner housing 16, a central fuel gun 17, an annular gas collector 18, a combustion air inlet 19, an annular gas gun 20, a cyclone separator 21, a bottom combustion chamber 22, and a secondary air porous distribution structure 23.

[0106] A secondary air porous distribution structure 23 is disposed within the bottom combustion chamber 22, dividing the bottom combustion chamber 22 into an inner combustion chamber and an outer combustion chamber. The inner combustion chamber is the space within the secondary air porous distribution structure 23, while the outer combustion chamber is the space formed by the secondary air porous distribution structure 23 and the inner wall of the bottom combustion chamber 22. The porous structure on the secondary air porous distribution structure 23 allows for communication between the inner and outer combustion chambers.

[0107] The burner housing 16 can communicate with the bottom combustion chamber 22. The burner housing 16 can be equipped with a central fuel gun 17, an annular gas collector 18, and a combustion air inlet 19.

[0108] The center fuel gun 17 extends into the burner housing 16 to deliver auxiliary fuel into the combustion chamber cavity of the bottom combustion chamber 22. The center fuel gun 17 can be a gas gun or an oil gun. One end of the center fuel gun 17 can be fixed to the end of the burner housing 16, and the central axis of the center fuel gun 17 can be aligned with the central axis of the bottom combustion chamber 22.

[0109] exist Figure 4 In the illustrated embodiment, a swirler 21 may be provided at the front end of the central fuel gun 17. The swirler 21 can be used to form swirling combustion in the combustion chamber, shorten the flame length, increase the flue gas mixing speed, and enable rapid combustion and mixing to be completed in the limited combustion chamber, forming high-temperature flue gas with a uniform temperature field, and ensuring that the high-temperature flue gas fed into the fluidized bed furnace 9 is evenly distributed.

[0110] The swirling flame and secondary air can mix relatively quickly, enabling rapid combustion and mixing within the limited combustion chamber, resulting in high-temperature flue gas with a uniform temperature field. This high-temperature flue gas can be blown out from the air distribution plate cap at the bottom of the fluidized bed furnace 9, fluidizing the bed material and other materials. The bottom flue gas volume is controlled to be 40-65% of the total flue gas volume, and the bottom burner load accounts for 30%-40% of the overall unit combustion load.

[0111] The circumferential gas collector 18 can surround the outer periphery of the central fuel gun 17. The circumferential gas collector 18 also has multiple circumferential gas guns 20 fixed to it. One end of each circumferential gas gun 20 is fixed to the circumferential gas collector 18 and adheres to the inner wall of the combustion chamber 22, thereby transferring heat and gas into the combustion chamber. The multiple circumferential gas guns 20 can be evenly arranged around the circumference of the circumferential gas collector 18. The number n of the circumferential gas guns 20 depends on the load. The value of n is generally in the range of 3-18.

[0112] The combustion air inlet 19 can be fixed above the burner housing 16. The combustion air inlet 19 is divided into two combustion air channels by a partition, thus separating the combustion air into two stages. Primary air enters the burner housing 16 through the first combustion air channel and is delivered to the combustion chamber cavity, responsible for ignition and central area combustion. Secondary air enters the space between the combustion chamber cavity and the combustion chamber outer cavity through the second combustion air channel, and then enters the combustion chamber cavity of the bottom combustion chamber 22 through the secondary air porous distribution structure 23.

[0113] In some embodiments, the secondary air porous distribution structure 23 can be an axial multi-stage air intake structure. For example, the first-stage air intake has 12-60 holes, generally arranged in a single row. The air intake area is designed according to the air intake volume. The air intake volume is controlled so that the overall excess air coefficient of the central combustion reaches 1.0-1.5. The second row of air intakes is located at the rear end of the secondary air porous distribution structure 23 (the end opposite to the burner housing 16), with 24-120 holes, generally arranged in 2-3 rows, injecting all remaining combustion air. The air intake area is designed according to the air intake volume. The air intake volume is controlled so that the overall excess air coefficient of the central combustion reaches 3-4.

[0114] The high-temperature flue gas generator adopts a separate air distribution method, and its main functions are: 1) to burn auxiliary fuels for start-up or operation, such as natural gas and diesel, mainly for start-up preheating and supplementary combustion conditions; 2) to burn a portion of the pyrolysis gas during organic solid waste feeding, which is used to increase the temperature of the hot air entering the furnace and ensure that the pyrolysis carbon on the air distribution plate reaches the combustion temperature. The temperature of the high-oxygen flue gas generated after combustion in the bottom burner is required to be >500℃; 3) The high excess air coefficient can easily lead to combustion instability. By adopting an air-staged combustion technology, the excess air coefficient of the central combustion is controlled at 0.6-0.9. Due to diffusion combustion, it can achieve stable combustion and reduce the generation of thermal NOx; the remaining air is injected from the secondary air porous air distribution structure 23 for rapid cooling and reduced NOx generation.

[0115] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A solid heat carrier heating device, characterized in that, The device comprises a pyrolysis reactor (5), a fluidized bed furnace (9), a gas-solid separator (8), a mechanical return feeder (3) and a flue gas generator (1); The pyrolysis reactor (5) is used for conveying solid pyrolysis reactants to the fluidized bed furnace (9) for reaction; the gas-solid separator (8) is used for gas-solid separation of reaction products of the fluidized bed furnace (9) to obtain solid heat carriers, which are conveyed to the fluidized bed furnace (9) for reaction through the mechanical return feeder (3); and the flue gas generator (1) is used for conveying flue gas to the fluidized bed furnace (9) to heat the solid pyrolysis reactants and the solid heat carriers; The pyrolysis reactor (5) is connected between the gas-solid separator (8) and the mechanical return feeder (3), and is used for conveying the solid heat carriers and the solid pyrolysis reactants to the fluidized bed furnace (9) through the mechanical return feeder (3); the device further comprises a double-leg upper bin (7), which comprises a control bin and an overflow bin; the control bin is connected between the gas-solid separator (8) and the pyrolysis reactor (5), and is used for conveying solid heat carrier particles to the pyrolysis reactor (5); and the overflow bin is connected with the fluidized bed furnace (9), and is used for conveying the solid heat carrier particles overflowing from the control bin to the fluidized bed furnace (9); The fluidized bed furnace (9) is provided with a multi-stage trapezoidal platform, which is located between the flue gas generator (1) and the mechanical return feeder (3) in the height direction, the inner diameter of the lower step surface of the multi-stage trapezoidal platform is smaller than the area of the upper step surface of the multi-stage trapezoidal platform; the multi-stage trapezoidal platform satisfies that the area of the lowermost step surface is 35%-50% of the cross-sectional area of the dilute phase zone of the fluidized bed furnace (9); the height between adjacent two step surfaces is 0.2-0.4 m; and the area of the upper step surface is 10-30% larger than that of the lower step surface; The fluidized bed furnace (9) is provided with a plurality of layers of side wall burners (2), the plurality of layers of side wall burners (2) and the mechanical return feeder (3) are oppositely arranged, the number of each layer of side wall burners is a plurality, and the plurality of layers of side wall burners are symmetrically or circumferentially uniformly arranged, and each side wall burner is inclined downward by 5-30°; the plurality of layers of side wall burners (2) satisfy any one of the following conditions: The number of layers of the plurality of layers of side wall burners (2) is three, the setting height of the first layer of side wall burners is 1.5-2.5 m, the setting height of the second layer of side wall burners is 2.6-3.5 m, the setting height of the third layer of side wall burners is more than 3.6 m, the downward inclination angle of the first layer of side wall burners is α1, the downward inclination angle of the second layer of side wall burners is α2, the downward inclination angle of the third layer of side wall burners is α3, and α1≥α2≥α3; The number of layers of the multi-layer side wall burner (2) is 2, the setting height of the first layer side wall burner is 2.6-3.5 m, the setting height of the second layer side wall burner is 3.6 m or above, the downward inclination angle of the first layer side wall burner is α2, and the downward inclination angle of the second layer side wall burner is α3, and α2≥α3; The number of layers of the multi-layer side wall burner (2) is 2, the setting height of the first layer side wall burner is 1.5-2.5 m, the setting height of the second layer side wall burner is 2.6-3.5 m, the downward inclination angle of the first layer side wall burner is α1, and the downward inclination angle of the second layer side wall burner is α2, and α1≥α2; The number of layers of the multi-layer side wall burner (2) is 2, the setting height of the first layer side wall burner is 1.5-2.5 m, the setting height of the second layer side wall burner is 3.6 m or above, the downward inclination angle of the first layer side wall burner is α1, and the downward inclination angle of the second layer side wall burner is α3, and α1≤α3; The dilute phase zone of the fluidized bed hearth (9) is provided with a tertiary air port (10), and the tertiary air is injected into the fluidized bed hearth (9) through the tertiary air port (10) at a tangential angle β, and 0°≤β≤75°.

2. The apparatus of claim 1, wherein, The double-leg upper bin (7) satisfies at least one of the following conditions: The lower end of the overflow bin has a U-shaped return structure; The distance between the return port of the overflow bin connected with the fluidized bed hearth (9) and the air distribution plate in the fluidized bed hearth (9) is 1-2 m; In the case of no chlorine-containing waste plastics, oil sludge, tires and sludge, a single-path connection is adopted between the control bin and the pyrolysis reactor (5); In the case of chlorine-containing component plastics, a multi-path connection is adopted between the control bin and the pyrolysis reactor (5).

3. The apparatus of claim 1, wherein, The device further comprises: A burnout adiabatic channel (12) and a settling heat exchange channel (14), the flue gas separated by the gas-solid separator (8) enters the settling heat exchange channel (14) through the burnout adiabatic channel (12), the burnout adiabatic channel (12) is a flue gas descending channel, the settling heat exchange channel (14) is a flue gas ascending channel, and baffles are arranged at the connection between the burnout adiabatic channel (12) and the settling heat exchange channel (14), and eight-shaped turbulence plates (13) are arranged in the burnout adiabatic channel (12) and the settling heat exchange channel (14).

4. The apparatus of claim 1, wherein, The flue gas generator (1) comprises: A combustion chamber (22) and a secondary air multi-hole air distribution structure (23), the secondary air multi-hole air distribution structure (23) is arranged in the combustion chamber (22), and the combustion chamber (22) is divided into a combustion chamber inner cavity and a combustion chamber outer cavity by the secondary air multi-hole air distribution structure (23); A burner shell (16) in communication with the combustion chamber inner cavity; A burner shell (16) in communication with the combustion chamber inner cavity; The combustion-supporting air inlet (19) is arranged on the burner shell (16) and comprises a first combustion-supporting air passage and a second combustion-supporting air passage, the first combustion-supporting air passage enters the combustion chamber inner cavity through the burner shell (16) and is used for realizing an air excess coefficient of 0.6-0.9, and the second combustion-supporting air passage is communicated with the combustion chamber outer cavity; The secondary air multi-hole air distribution structure (23) has a first-stage air inlet hole, the first-stage air inlet hole is located on the side of the secondary air multi-hole air distribution structure (23) close to the burner shell (16), and the first-stage air inlet hole and the first combustion-supporting air passage are superposed to realize an air excess coefficient of 1.0-1.5.

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