A multi-tube cascade heating non-tar carbonization device and method

Abstract

The present application belongs to the technical field of biomass or solid waste resource utilization, and particularly relates to a multi-pipe gradient heating tar-free carbonization equipment and method, wherein the carbonization equipment comprises a multi-pipe gradient heating equipment main body and a combustion heating chamber in communication with the equipment main body, and a gas pipeline downstream of the combustion heating chamber is in communication with a tar cracking chamber; a plurality of blocking components are fixedly arranged in the tar cracking chamber and staggered along the gas flow direction, so that the gas makes a detour in the tar cracking chamber; and a tar catalyst for tar cracking is filled between at least some of the blocking components. The present application realizes complete catalytic cracking of tar under the premise of ensuring production continuity and high efficiency, guarantees the quality of carbonization products through zoned temperature control, is energy-saving and economical, and is suitable for tar-free carbonization of biomass or solid waste.

Description

Technical Field

[0001] This invention belongs to the field of biomass or solid waste resource utilization technology, and relates to a carbonization equipment and method, specifically a multi-tube stage heating tar-free carbonization equipment and method. Background Technology

[0002] Biomass carbonization technology involves pyrolyzing biomass raw materials such as wood and straw under anaerobic or air-deficient conditions to obtain solid charcoal products, combustible gas, and liquid products. This technology is of great significance for realizing the high-value utilization of biomass resources and carbon sequestration and emission reduction. Traditional carbonization equipment, such as brick kilns and stationary single-unit carbonization furnaces, typically operates in an intermittent manner. Such equipment generally suffers from low thermal energy utilization, long production cycles, and low levels of automation, resulting in low overall production efficiency. Simultaneously, the production process is accompanied by the fugitive emission of large amounts of smoke and dust and condensable volatiles, causing serious environmental pollution, and placing high demands on the labor intensity and working environment of operators.

[0003] To improve production efficiency, various continuous or semi-continuous carbonization furnaces have been developed in existing technologies. These devices achieve continuity between feeding and carbon output to a certain extent, thus improving production efficiency. However, the problem of tar byproducts generated during the carbonization process remains a core bottleneck restricting technological development. The volatiles produced by biomass pyrolysis condense to form complex tar, the main hazards of which are: firstly, condensation and deposition in pipelines, valves, and subsequent processing equipment, leading to pipeline blockage and equipment corrosion, affecting the long-term stable operation of the system; secondly, tar itself is a toxic and harmful substance, and if it is directly emitted with flue gas or lost with wastewater, it will cause secondary pollution.

[0004] To address the tar problem, existing technologies mainly employ two approaches. The first is a collection-and-disposal approach, which involves installing complex purification systems at the carbonization gas outlet, including condensation, washing, and electrostatic precipitator systems, to separate and collect the tar from the gas phase. While this method can temporarily avoid pipeline blockage, it essentially transfers gaseous pollution into more difficult-to-treat liquid or solid hazardous waste, significantly increasing subsequent hazardous waste disposal costs and environmental risks. The second approach is in-situ pyrolysis and elimination, which attempts to break down the tar into smaller combustible molecules within the system at high temperatures. A common implementation involves introducing a portion of the combustible flue gas into the combustion chamber for combustion, generating high-temperature flue gas to heat the carbonization section or directly treating the tar components at high temperatures. However, limited by traditional furnace structures, this method often suffers from uneven temperature distribution, insufficient mixing between the high-temperature zone and the reacting gas, and insufficient residence time of tar molecules in the high-temperature zone. This results in incomplete tar pyrolysis, with a large amount of intermediate products still being generated, failing to fundamentally achieve efficient and clean conversion of tar. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a multi-tube, cascade heating tar-free carbonization device and method, thereby achieving the goal of solving the tar pollution problem at the source of production while ensuring efficient and continuous production.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a multi-tube stepped heating tar-free carbonization device, comprising a multi-tube stepped heating device body and a combustion heating chamber connected to the device body, wherein a tar cracking chamber is connected downstream of a gas pipe inside the combustion heating chamber;

[0007] The tar pyrolysis chamber is equipped with several barrier components arranged alternately along the gas flow direction, which allows the gas to move in a meandering manner within the tar pyrolysis chamber. At least some of the barrier components are filled with tar catalysts for tar pyrolysis.

[0008] As a limitation of the present invention: the barrier component is a fire-resistant barrier plate, and at least some of the barrier components are detachably provided with drawers, and the tar catalyst is filled in the drawers.

[0009] As a limitation of the present invention: the gas outlet of the tar pyrolysis chamber is connected to the gas recirculation and output system, which includes an output port for external gas supply and a recirculation structure for connection to the combustion heating chamber.

[0010] As a limitation of the present invention: the reflux structure includes a reflux pipeline and a buffer chamber connected to the reflux pipeline. The buffer chamber is connected to the combustion chamber through an oxygen supply pipeline. The reflux structure also includes an oxygen chamber connected to the oxygen supply pipeline, and an air inlet is provided on the oxygen chamber.

[0011] As a limitation of the present invention: the main body of the equipment includes a heat preservation chamber connected to the combustion heating chamber, and a drying pipe, a low-temperature carbonization pipe and a high-temperature carbonization pipe are sequentially connected in the heat preservation chamber along the material conveying direction; the drying pipe, the low-temperature carbonization pipe and the high-temperature carbonization pipe are arranged sequentially from top to bottom and connected end to end by a star-shaped sealing unloader.

[0012] As a limitation of the present invention: the drying tube, the low-temperature carbonization tube, and the high-temperature carbonization tube are all arranged in a horizontal direction, with at least two of each type of tube arranged parallel to each other, and gaps left between adjacent tubes; the insulation chamber includes a drying chamber for accommodating the drying tube, a low-temperature carbonization chamber for accommodating the low-temperature carbonization tube, and a high-temperature carbonization chamber for accommodating the high-temperature carbonization tube. The drying chamber, the low-temperature carbonization chamber, and the high-temperature carbonization chamber are separated from each other and are provided with connecting ports. The combustion heating chamber is connected to the high-temperature carbonization chamber, and the connecting port is located at the feed end of the high-temperature carbonization tube. A direct connecting pipeline is also provided between the discharge ends of the combustion heating chamber and the low-temperature carbonization chamber.

[0013] As a limitation of the present invention: the drying tube, the low-temperature carbonization tube and the high-temperature carbonization tube are all provided with a rotating shaft, and the rotating shaft is fixed with a paddle-type blade or a sickle-type blade, and the rotating shaft is provided with a water-cooling structure.

[0014] As a limitation of the present invention: the upstream of the gas pipeline is connected to the low-temperature carbonization pipe and / or the high-temperature carbonization pipe, and the downstream of the gas pipeline is connected to the tar cracking chamber; in the tar cracking chamber, upstream of the tar catalyst, a dust collection chamber is detachably provided, and a porous dust collection material is placed in the dust collection chamber.

[0015] This invention also discloses a multi-tube staged heating tar-free carbonization method, implemented using the aforementioned multi-tube staged heating tar-free carbonization equipment, comprising the following steps:

[0016] The material is dried through a drying tube;

[0017] The material is carbonized at low temperature through a low-temperature carbonization tube, and volatiles are released. The temperature of the low-temperature carbonization is 250-370℃.

[0018] The material is carbonized at high temperature through a high-temperature carbonization tube, and volatiles are released to complete the carbonization reaction. The high-temperature carbonization temperature is 380-520℃.

[0019] The volatiles are collected in the tar cracking chamber, where the tar is cracked under the action of temperature and catalyst to generate clean syngas.

[0020] The syngas is partially returned to the combustion heating chamber as fuel through the gas recirculation and output system, and partially used for external gas supply.

[0021] As a limitation of the present invention: the low-temperature carbonization tube includes a first low-temperature carbonization section located at the front end of the material conveying direction and a second low-temperature carbonization section located at the rear end of the material conveying direction, wherein the carbonization temperature of the first low-temperature carbonization section is 250-280°C and the carbonization temperature of the second low-temperature carbonization section is 330-370°C.

[0022] The high-temperature carbonization tube includes a first high-temperature carbonization section located at the front end of the material conveying direction and a second high-temperature carbonization section located at the rear end of the material conveying direction. The carbonization temperature of the first high-temperature carbonization section is 480-520℃, and the carbonization temperature of the second low-temperature carbonization section is 380-420℃.

[0023] By adopting the above technical solution, the beneficial effects achieved by the present invention compared with the prior art are as follows:

[0024] (1) This invention introduces tar-containing volatile gases into the tar pyrolysis chamber and innovatively adopts a labyrinth structure design to force the gas to circulate, extending its residence time to more than 5 seconds, thus providing key conditions for a full reaction. Furthermore, during tar pyrolysis, both high-temperature thermal pyrolysis and catalytic pyrolysis are combined. At the front end of the pyrolysis chamber, a high temperature of 800–1100℃ is used to directly break the C-C bonds of tar macromolecules. In the middle and later stages, a special tar catalyst is filled to significantly reduce the pyrolysis temperature to the optimal range of 500–800℃. The catalyst lowers the reaction activation energy, causing preferential bond breaking and reorganization of tar macromolecules on their surface, thereby increasing the tar conversion rate to over 90% and effectively suppressing the carbon black coking problem that easily occurs with simple high-temperature pyrolysis. This not only converts pollutants into high-calorific-value small-molecule combustible gases such as methane, carbon monoxide, and hydrogen, but also completely eliminates the problems of tar clogging and corrosion of pipelines and equipment, as well as its disposal as hazardous waste, from the source of the reaction.

[0025] (2) The main body of the equipment of the present invention adopts a multi-layer pipeline design and achieves closed series connection of the beginning and end through a star-shaped sealed unloader, so that the material can be continuously fed, conveyed in stages, carbonized and discharged, which completely changes the disadvantages of low production efficiency and high labor intensity of traditional intermittent kilns. The pipelines of each section can operate independently and the transmission dimension is controllable. The parallel arrangement of multiple pipes greatly increases the material processing area in a limited space, thereby ensuring the high efficiency and smoothness of the production process and the improvement of single machine capacity.

[0026] (3) By setting up independent heat preservation spaces for different pyrolysis stages, this invention achieves precise supply and tiered utilization of heat required for different temperatures in drying, low-temperature carbonization, and high-temperature carbonization, thus avoiding the waste of energy quality. More importantly, the high-calorific-value clean syngas after thorough pyrolysis and purification can be partially recycled back to the combustion heating chamber as the main fuel to provide energy for the system itself, reducing dependence on external fuel and achieving energy self-sufficiency of the system; excess gas can also be supplied externally to create additional revenue, making it economically significant.

[0027] (4) This invention utilizes an independent temperature chamber design and, through the interconnection structure and location between the temperature chambers, combined with the material conveying sequence of the three pipelines, enables precise stepped temperature control of the material pyrolysis process in a "low temperature-high temperature-low temperature" manner. This scientific temperature zone arrangement, which conforms to the kinetics of biomass pyrolysis, allows volatile matter to be released steadily and fully, thereby ensuring that the final biochar product has excellent characteristics such as high fixed carbon content, stable structure, and uniform quality. The product stability is significantly better than that of traditional equipment.

[0028] (5) To address the pain point of the equipment operating in a high-temperature environment for extended periods, this invention incorporates a targeted design to ensure durability. A water-cooling structure is integrated into the rotating shafts within each carbonization tube, effectively dissipating the heat generated by the continuous rotation of the core transmission components in the high-temperature material, ensuring its long-term operational reliability. Simultaneously, the labyrinthine barrier components of the tar cracking chamber are made of high-temperature refractory materials, capable of withstanding the long-term high-temperature environment of catalytic cracking. Their excellent thermal shock resistance and durability guarantee the service life of the cracking core unit and reduce maintenance costs.

[0029] In summary, this invention achieves complete catalytic cracking of tar while ensuring continuous and efficient production, and guarantees the quality of carbonization products through zoned temperature control. It is also energy-saving and economical, and is suitable for tar-free carbonization of biomass or solid waste. Attached Figure Description

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a front view of an embodiment of the present invention;

[0032] Figure 2 This is a top view of the main body of the device in an embodiment of the present invention;

[0033] Figure 3 This is a front view of the pyrolysis chamber in an embodiment of the present invention;

[0034] Figure 4 This is a front view of the combustion heating chamber and the gas recirculation and output system in an embodiment of the present invention.

[0035] In the diagram: 1-Drying pipe, 2-Low-temperature carbonization pipe, 3-High-temperature carbonization pipe, 4a-First star-shaped sealing unloader, 4b-Second star-shaped sealing unloader, 4c-Third star-shaped sealing unloader, 4d-Fourth star-shaped sealing unloader, 5-Combustion heating chamber, 6-Tar cracking chamber, 61-Barrier component, 62-Catalyst, 63-Dust collection material, 64-Direct connection pipe, 7-Gas pipe, 8-Guide plate, 9-Gas distribution pipe, 91-Induced draft fan, 92-Pressure transmitter, 9a-Return pipe, 9b-Outlet, 10-Insulation chamber, 101-Drying chamber, 102-Low-temperature carbonization chamber, 103-High-temperature carbonization chamber, 11-Rotating shaft, 12-Paddle blade, 13-Buffer chamber, 14-Oxygen chamber, 15-Air inlet, 16-Oxygen supply pipe. Detailed Implementation

[0036] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the multi-tube stage heating tar-free carbonization equipment and method described herein are preferred embodiments and are only used for illustration and explanation of the present invention, and do not constitute a limitation thereof.

[0037] The directional terms or positional relationships used in this invention, such as "up," "down," "left," and "right," are based on the positional relationships in the accompanying drawings of this invention. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component must have a specific orientation, or that it must be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the content protected by this invention.

[0038] Example 1: Multi-tube stage heating tar-free carbonization equipment

[0039] like Figures 1 to 4 As shown, this embodiment provides a multi-tube cascade heating tar-free carbonization device. The device is a steel structure with a three-dimensional layout, mainly including the main body of the device, a combustion heating chamber 5, and an integrated tar pyrolysis chamber 6.

[0040] The main body of the equipment includes a heat preservation chamber 10. Inside the heat preservation chamber 10, along the material conveying direction, from top to bottom, are connected and arranged a drying pipe 1, a low-temperature carbonization pipe 2, and a high-temperature carbonization pipe 3. Specifically, there are two drying pipes 1 arranged in parallel horizontally; two low-temperature carbonization pipes 2 arranged in parallel horizontally; and two high-temperature carbonization pipes 3 arranged in parallel horizontally. A gap of about 15 to 20 centimeters is left between adjacent pipes to ensure uniform heating. The drying tube 1, the low-temperature carbonization tube 2, and the high-temperature carbonization tube 3 are separated in different heat-insulating spaces, but these heat-insulating spaces are interconnected through openings to jointly form the relatively independent heat-insulating chamber 10, so as to achieve precise temperature control by zone. Specifically, in this embodiment, the heat-insulating chamber 10 includes a drying chamber 101 for accommodating the drying tube 1, a low-temperature carbonization chamber 102 for accommodating the low-temperature carbonization tube 2, and a high-temperature carbonization chamber 103 for accommodating the high-temperature carbonization tube 3. The drying chamber 101, the low-temperature carbonization chamber 102, and the high-temperature carbonization chamber 103 are separated from each other and connected by a gate valve (not shown in the figure). Furthermore, the combustion heating chamber 5 is connected to the high-temperature carbonization chamber 103, and the connection port is located at the feed end of the high-temperature carbonization tube 3. The high-temperature carbonization chamber 103 is connected to the low-temperature carbonization chamber 102, and the connection port is located at the feed end of the low-temperature carbonization tube 2. The low-temperature carbonization chamber 102 is connected to the drying chamber 101, with two connection ports located in the middle of the drying tube 1 and at the feed end, respectively. In addition, a direct connection pipeline is provided between the combustion heating chamber 5 and the discharge end of the low-temperature carbonization chamber 102. A valve for adjusting the gas volume can be further installed on the direct connection pipeline so that the heat of the low-temperature carbonization tube 2 does not only come from the lower temperature flue gas in the lower layer, but also directly introduces higher temperature flue gas from the combustion system at the bottom. This high-temperature flue gas will be injected into the latter half of the low-temperature carbonization tube 2, so the latter half of the low-temperature carbonization tube 2 will receive higher heat input and the temperature will be higher than that of the first half. During production, the temperature of the entire pipeline decreases sequentially from high to low as follows: the front section of high-temperature carbonization pipe 3, the rear section of high-temperature carbonization pipe 3, the rear section of low-temperature carbonization pipe 2, the front section of low-temperature carbonization pipe 2, and drying pipe 1, achieving a stepped temperature transfer. Each temperature segment is equipped with a thermocouple, which is linked to the control system (not shown in the figure). Temperature control is achieved by adjusting the opening degree of the gate valve and the direct-connection pipeline, ensuring the aforementioned temperature gradient from high to low. Furthermore, each of the drying chamber, low-temperature carbonization chamber, and high-temperature carbonization chamber is equipped with a spiral-structured gas guide plate 8 along the material conveying direction, allowing the gas to remain sufficiently within the insulation chamber. It should be noted that in other embodiments, the number of drying pipe 1, low-temperature carbonization pipe 2, and high-temperature carbonization pipe 3 can be adjusted as needed.

[0041] Material transfer between the pipelines is achieved through multiple star-shaped sealed unloaders. Specifically, a first star-shaped sealed unloader 4a is installed at the feed end of the drying pipe 1 to receive and seal the feed; the discharge end of the drying pipe 1 is connected to the feed end of the low-temperature carbonization pipe 2 via a second star-shaped sealed unloader 4b; the discharge end of the low-temperature carbonization pipe 2 is connected to the feed end of the high-temperature carbonization pipe 3 via a third star-shaped sealed unloader 4c. These unloaders are staggered at both ends of the equipment, allowing the material to be transported from top to bottom along an "S"-shaped path, ensuring continuous transport while effectively isolating the atmosphere between the pipelines and preventing oxygen crosstalk. A fourth star-shaped sealed unloader 4d is also installed at the discharge end of the high-temperature carbonization pipe 3, which is connected to a water-cooled auger cooling device (not shown in the figure) to cool the carbonized high-temperature material to a safe temperature of 50-60℃. The structure of the water-cooled auger cooling device is existing technology and will not be described in detail here.

[0042] The drying tube 1, low-temperature carbonization tube 2, and high-temperature carbonization tube 3 are all equipped with rotatable shafts 11. Paddle blades 12 for propelling and turning the material are fixed on the shafts 11. In other embodiments, sickle blades may also be used. All shafts 11 have integrated water-cooling structures and are equipped with cooling water inlets and outlets (not shown in the figure). Cooling water is continuously supplied to remove heat, ensuring that the transmission components operate stably for a long time in high-temperature environments without overheating, deformation, or damage.

[0043] Combustion heating chamber 5 is located at the bottom of the main body of the equipment and is used to provide the heat required for the carbonization process. The combustion heating structure inside combustion heating chamber 5 is existing technology and will not be described in detail here. Volatile matter from low-temperature carbonization tube 2 and high-temperature carbonization tube 3 is collected and discharged through gas pipe 7. The upstream of gas pipe 7 is connected to low-temperature carbonization tube 2 through a "T"-shaped pipe and to high-temperature carbonization tube 3 through a "+"-shaped pipe. The downstream of gas pipe 7 extends into the interior of combustion heating chamber 5 and connects to tar cracking chamber 6 located inside combustion heating chamber 5.

[0044] like Figure 3 As shown, the tar cracking chamber 6 is composed of multiple barrier components 61 arranged in a staggered pattern along the gas flow direction. Specifically, each barrier component 61 is a refractory baffle made of refractory material. These baffles form a labyrinthine channel that forces the gas to move in a circuitous manner, causing the gas to... Figure 3The flow proceeds in the direction of the arrow. A drawer is detachably installed between the channels of the partially blocking components 61. The drawer has openings for the catalyst used to promote tar cracking, which is then filled and easily replaced. This structure significantly extends the residence time of tar-containing gas in the high-temperature zone to more than 5 seconds, ensuring sufficient contact between the gas and the catalyst. In different embodiments, the location and amount of catalyst can be adjusted as needed. Furthermore, the catalyst is any one or more of dolomite, olivine, charcoal, or Rh / CeO / SiO. Dolomite and olivine are natural mineral catalysts, characterized by their easy availability and low cost. Using charcoal as a catalyst, tar can be 100% cracked into low-calorific-value fuel gas at 950℃. Adding an appropriate amount of steam further enhances stability and resists carbon buildup, effectively preventing the catalytic efficiency from decreasing due to carbon buildup during the cracking process. Rh / CeO / SiO is a composite catalyst with good stability and anti-carbon deposition properties, which can effectively prevent the catalytic efficiency of the catalyst from being reduced due to carbon deposition during tar cracking. Furthermore, in the tar cracking chamber, a dust collection chamber is detachably installed upstream of the drawer used to house the tar catalyst 62. In this embodiment, the dust collection chamber is also a drawer-type structure, containing a porous dust collection material 63. The drawer-type structure facilitates regular cleaning of dust and replacement of the dust collection material 63. In this embodiment, the dust collection material 63 is a stainless steel wire ball, which provides a porous structure for dust adsorption and collection. Furthermore, the upstream and downstream of the tar pyrolysis chamber 6 are directly connected via a direct connection pipe 64, and valves are installed on the upstream and downstream of the tar pyrolysis chamber 6 and on the direct connection pipe 64. With this configuration, when replacing the tar catalyst, the valves on the upstream and downstream of the tar pyrolysis chamber 6 are closed, and the valve on the direct connection pipe 64 is opened, allowing the flue gas to temporarily flow normally through the direct connection pipe 64, thus preventing the leakage of flue gas when replacing the tar catalyst. Under normal operating conditions of the tar pyrolysis chamber 6, closing the valve on the direct connection pipe 64 will not affect the temperature of the device.

[0045] The outlet of tar cracking chamber 6 is connected to the fuel gas recirculation and output system, such as... Figure 4As shown (arrows in the figure indicate the gas delivery direction), the gas recirculation and output system includes a gas distribution pipe 9. The gas distribution pipe 9 is equipped with an induced draft fan 91 and a pressure transmitter 92. The induced draft fan 91 generates negative pressure, and the pressure transmitter 92 monitors the negative pressure in real time, preventing air from entering and oxidizing the charcoal while also discharging residual gas. The gas distribution pipe 9 has two outlets: an outlet 9b for drawing out excess gas for external use (a valve, not shown in the figure, is installed on outlet 9b). The recirculation pipe 9a connects to the burner in the combustion heating chamber 5, allowing some of the pyrolysis-derived clean gas to be reused as fuel. As part of the recirculation structure, the recirculation pipe 9a is connected to the buffer chamber 13 via a valve. The buffer chamber 13 is connected to the combustion heating chamber 5 via an oxygen supply pipe 16. The recirculation structure also includes an oxygen chamber 14 connected to the oxygen supply pipe 16, with an air inlet 15 for adding oxygen to the combustion heating chamber 5.

[0046] Example 2: Multi-tube staged heating method for tar-free carbonization

[0047] This embodiment provides a multi-tube staged heating tar-free carbonization method based on the equipment described in Embodiment 1, including the following steps:

[0048] S1: Continuous feeding and drying. The crushed biomass raw materials, such as sawdust and straw, are continuously and sealedly fed into the two upper drying pipes 1 through the first star-shaped sealed unloader 4a. Inside the drying pipes 1, the material is indirectly heated by the residual heat from the lower low-temperature carbonization pipes 2 and high-temperature carbonization pipes 3, which preheats and dries the material, removing most of the moisture.

[0049] S2: Staged low-temperature carbonization and initial volatile matter precipitation. The dried material is evenly fed into the two low-temperature carbonization tubes 2 in the middle layer via the second star-shaped sealed unloader 4b. The low-temperature carbonization process is divided into two stages: in the front section of the material conveying direction (first low-temperature carbonization section), the temperature is maintained at approximately 260℃ through precise temperature control, and the material undergoes initial pyrolysis; in the rear section of the material conveying direction (second low-temperature carbonization section), the temperature rises to approximately 350℃, and a large amount of volatile matter begins to rapidly precipitate. The rotating shaft 11 inside the low-temperature carbonization tube 2 continuously rotates, driving the paddle blades 12 to agitate the material, ensuring uniform heating.

[0050] S3: Staged High-Temperature Carbonization and Volatile Matter Re-precipitation. After preliminary pyrolysis, the material falls through the third star-shaped sealed unloader 4c into a lower set of high-temperature carbonization pipes 3. The high-temperature carbonization process is divided into two stages: in the front section of the material conveying direction (first high-temperature carbonization stage), the temperature is controlled at a maximum of approximately 500℃, where the material undergoes deep carbonization and structural restructuring; in the rear section of the material conveying direction (second high-temperature carbonization stage), the temperature drops to approximately 400℃ to complete carbonization and stabilize product properties, yielding biochar with a high fixed carbon content. A large amount of volatile matter is also released during this stage.

[0051] S4: Discharge and Cooling. The carbonized incandescent biochar is discharged through the fourth star-shaped sealed unloader (4d) and immediately enters the water-cooled auger cooling device. While the material is being conveyed inside the auger, it exchanges heat with the cooling water flowing counter-currently inside the auger shell jacket, and is finally cooled to 50-60℃, becoming a stable and safe final product, achieving continuous discharge.

[0052] S5: Volatile Matter Collection and Tar Catalytic Cracking. The mixed volatile gases released in steps S2 and S3 are collected uniformly through gas pipeline 7 and introduced into the tar cracking chamber 6 located in the center of the combustion heating chamber 5 under negative pressure. The mixed gas is forced to flow in a meandering manner within the labyrinthine channel, with a residence time exceeding 5 seconds. Under the combined action of the high-temperature environment above 800°C provided by the combustion heating chamber 5 and the filled tar catalyst, the large tar molecules in the gas are efficiently catalytically cracked, with a conversion rate exceeding 90%, generating clean small-molecule syngas mainly composed of methane, carbon monoxide, hydrogen, etc., while inhibiting the formation of carbon black.

[0053] S6: Syngas Reuse and External Supply. The clean syngas produced in step S5 is distributed by the gas distribution pipeline 9. Approximately 30% to 50% of the gas is recycled back to the burner in the combustion heating chamber 5 as the main fuel to maintain the system's high-temperature heat source, forming an efficient internal energy cycle and significantly reducing external fuel consumption; the remainder is output as high-quality clean energy for external use.

[0054] The composition and content of the clean synthesis gas supplied for external use were analyzed, and the results are shown in Tables 1 and 2 below:

[0055] Table 1. Composition and content of biomass gas (unit: ×10) -2 mol / mol)

[0056]

[0057] Table 2. Composition and content of biomass gas

[0058]

[0059] As shown in Tables 1 and 2, the gas treated by this invention achieves complete catalytic cracking of tar.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-tube, staged heating, tar-free carbonization device, characterized in that, The equipment includes a main body with multi-pipe stepped heating and a combustion heating chamber connected to the main body. Downstream of the gas pipe inside the combustion heating chamber, there is a tar cracking chamber. The tar pyrolysis chamber is equipped with several barrier components arranged alternately along the gas flow direction, which allows the gas to move in a meandering manner within the tar pyrolysis chamber. At least some of the barrier components are filled with tar catalysts for tar pyrolysis.

2. The multi-tube stage heating tar-free carbonization equipment according to claim 1, characterized in that, The barrier component is a fire-resistant barrier plate, and at least some of the barrier components are detachably connected by drawers, with tar catalysts filled in the drawers.

3. The multi-tube stage heating tar-free carbonization equipment according to claim 2, characterized in that, The outlet of the tar pyrolysis chamber is connected to the gas recirculation and output system. The gas recirculation and output system includes an output port for external gas supply and a recirculation structure for connection to the combustion heating chamber. The upstream and downstream of the tar pyrolysis chamber are directly connected by a direct connection pipe, and valves are installed on the upstream and downstream of the tar pyrolysis chamber and on the direct connection pipe.

4. The multi-tube stage heating tar-free carbonization equipment according to claim 3, characterized in that, The reflux structure includes a reflux pipeline and a buffer chamber connected to the reflux pipeline. The buffer chamber is connected to the combustion chamber via an oxygen supply pipeline. The reflux structure also includes an oxygen chamber connected to the oxygen supply pipeline, and an air inlet is provided on the oxygen chamber.

5. The multi-tube stage heating tar-free carbonization equipment according to any one of claims 1 to 4, characterized in that, The main body of the equipment includes a heat preservation chamber connected to the combustion heating chamber. A drying pipe, a low-temperature carbonization pipe, and a high-temperature carbonization pipe are sequentially connected in the heat preservation chamber along the material conveying direction. The drying pipe, the low-temperature carbonization pipe, and the high-temperature carbonization pipe are arranged sequentially from top to bottom and connected end to end by a star-shaped sealing unloader.

6. The multi-tube stage heating tar-free carbonization equipment according to claim 5, characterized in that, The drying tube, low-temperature carbonization tube, and high-temperature carbonization tube are all arranged horizontally, with at least two of each type of tube arranged parallel to each other, and gaps left between adjacent tubes. The insulation chamber includes a drying chamber for accommodating the drying tube, a low-temperature carbonization chamber for accommodating the low-temperature carbonization tube, and a high-temperature carbonization chamber for accommodating the high-temperature carbonization tube. The drying chamber, low-temperature carbonization chamber, and high-temperature carbonization chamber are separated from each other and connected by a connection port. The combustion heating chamber is connected to the high-temperature carbonization chamber, and the connection port is located at the feed end of the high-temperature carbonization tube. A direct connection pipeline is also provided between the discharge ends of the combustion heating chamber and the low-temperature carbonization chamber.

7. The multi-tube stage heating tar-free carbonization equipment according to claim 6, characterized in that, The drying chamber, low-temperature carbonization chamber, and high-temperature carbonization chamber are all equipped with air guide plates with a spiral structure along the material conveying direction; the drying pipe, low-temperature carbonization pipe, and high-temperature carbonization pipe are all equipped with a rotating shaft, on which paddle-type blades or sickle-type blades are fixed, and the rotating shaft is equipped with a water-cooling structure.

8. The multi-tube stage heating tar-free carbonization equipment according to claim 4, characterized in that, The upstream of the gas pipeline is connected to the low-temperature carbonization pipe and / or the high-temperature carbonization pipe, and the downstream of the gas pipeline is connected to the tar cracking chamber; in the tar cracking chamber, upstream of the tar catalyst, a dust collection chamber is detachably installed, and a porous dust collection material is placed in the dust collection chamber.

9. A multi-tube staged heating method for tar-free carbonization, characterized in that, The multi-tube stage heating tar-free carbonization equipment according to any one of claims 5 to 8 includes the following steps: The material is dried through a drying tube; The material is carbonized at low temperature through a low-temperature carbonization tube, and volatiles are released. The temperature of the low-temperature carbonization is 250-370℃. The material is carbonized at high temperature through a high-temperature carbonization tube, and volatiles are released to complete the carbonization reaction. The high-temperature carbonization temperature is 380-520℃. The volatiles are collected in the tar cracking chamber, where the tar is cracked under the action of temperature and catalyst to generate clean syngas. The syngas is partially returned to the combustion heating chamber as fuel through the gas recirculation and output system, and partially used for external gas supply.

10. The multi-tube staged heating tar-free carbonization method according to claim 9, characterized in that, The low-temperature carbonization tube includes a first low-temperature carbonization section located at the front end of the material conveying direction and a second low-temperature carbonization section located at the rear end of the material conveying direction. The carbonization temperature of the first low-temperature carbonization section is 250-280℃, and the carbonization temperature of the second low-temperature carbonization section is 330-370℃. The high-temperature carbonization tube includes a first high-temperature carbonization section located at the front end of the material conveying direction and a second high-temperature carbonization section located at the rear end of the material conveying direction. The carbonization temperature of the first high-temperature carbonization section is 480-520℃, and the carbonization temperature of the second low-temperature carbonization section is 380-420℃.

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