Biomass pyrolysis gas ex-situ catalysis device with labyrinth gas passage and pyrolysis method

Abstract

The invention relates to the field of high-value utilization of organic solid wastes, in particular to a biomass pyrolysis gas ex-situ catalysis device with a labyrinth gas passage, which comprises a feeding furnace, a pyrolysis furnace, a rotating shaft and the labyrinth gas passage. In addition, the invention also provides a pyrolysis method. Biomass raw materials are preheated through high-temperature carrier gas and then subjected to pyrolytic reaction in the pyrolyzing furnace, and pyrolytic gas is guided into the labyrinth gas channel under the action of the induced draft gas pump, so that the pyrolytic gas spirally rotates in a high-temperature environment and makes full contact with a catalyst to generate catalytic reaction, conversion of by-products such as tar is promoted, and the pyrolysis effect is improved. The yield and the heat value of the non-condensable gas are improved. And meanwhile, the positive pressure in the equipment is maintained by the feeding furnace through the uniformly arranged carrier gas inlets, so that the high-temperature gas in the pyrolyzing furnace is prevented from being diffused to the feeding furnace. According to the invention, the ex-situ catalytic labyrinth gas passage is established above the pyrolysis space, so that the tar removal efficiency is remarkably improved, and tar, carbon dioxide and the like are promoted to be further converted into high-calorific-value biogas.

Description

Technical Field

[0001] The present invention relates to the field of high-value utilization of organic solid waste, and particularly relates to a non-in-situ catalytic device for biomass pyrolysis gas with a maze air passage and a pyrolysis method. Background Art

[0002] With the gradual depletion of fossil energy and the aggravation of environmental pollution, the development and utilization of renewable energy have become an urgent global demand. Biomass is a renewable resource with "zero carbon dioxide emissions", and its energy utilization and resource utilization have attracted increasing attention. Pyrolysis gasification is a very important means of biomass utilization, which can convert low-grade biomass resources into high-calorie bio-gas rich in carbon monoxide, hydrogen, and methane, not only improving the utilization quality of biomass energy but also enhancing its utilization efficiency.

[0003] However, in the process of biomass pyrolysis gasification, due to the incomplete decomposition of some volatile organic compounds in the pyrolysis reaction, a large amount of tar is generated as liquid heavy products. These tars usually exist in the form of viscous liquids, containing various complex aromatic hydrocarbons and other chemical components, which not only endanger human health but also cause the subsequent devices to work unstably, resulting in a large loss of organic available resources. At the same time, a certain amount of carbon dioxide in the biomass pyrolysis gasification products will cause a significant decrease in the calorific value of the pyrolysis gas products. Chinese Patent 202311754043.4 discloses a device and process for separating and removing tar in pyrolysis gas by a multi-layer curved plate, which sets a flow resistance structure on the external separation component to slow down the residence time of the pyrolysis gas on the separation component, thereby promoting the separation of tar. However, the external separation device cannot effectively solve the problem of loss of organic available resources, and the treatment of the separated tar increases the operating cost.

[0004] Currently, for the tar removal technology of biomass pyrolysis, external secondary cracking or catalytic cracking devices are generally used. However, the external cracking devices not only face problems such as equipment carbon deposition and catalyst deactivation but also increase the complexity of the process. At the same time, both pyrolysis and pyrolysis gas cracking require a certain temperature, which greatly increases the power consumption of the entire process route and the technical economy is poor. Therefore, it is urgent to develop a simple and efficient biomass pyrolysis tar disposal device to avoid complex secondary cracking equipment, improve the utilization efficiency of biomass resources, and achieve high-value utilization and resource utilization of biomass. Summary of the Invention

[0005] (1) Technical Problems to be Solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a non-in-situ catalytic device for biomass pyrolysis gas with a maze air passage and a pyrolysis method to solve the problems existing in the treatment of biomass pyrolysis tar by existing devices.

[0007] (2) Technical solution

[0008] To achieve the above object, a biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air duct provided by the present invention includes a feeding furnace, a pyrolysis furnace, a rotating shaft and a labyrinth air duct;

[0009] The feeding furnace is a hollow circular through-tube, and a feeding device is provided at the top of the head end of the feeding furnace;

[0010] In the cross-section of the pyrolysis furnace, the inner surface contour of the pyrolysis furnace is a contour shape where a circle is connected to a square. The bottom ends of the two equal-length opposite vertical sides of the square are respectively located on the circumference of the circle, and the width of the square is 0.5 to 1 times the diameter of the circle; the top wall of the pyrolysis furnace is inclined; in the cross-section of the tail end of the pyrolysis furnace, the height of the square is the tail end height, and the tail end height is less than the diameter of the circle; in the cross-section of the head end of the pyrolysis furnace, the height of the square is the head end height, and the head end height is greater than the tail end height; the tail end of the feeding furnace and the head end of the pyrolysis furnace are connected through communication; a discharge device is provided at the bottom of the tail end of the pyrolysis furnace;

[0011] The rotating shaft is coaxially arranged in the feeding furnace and extends to the tail end of the pyrolysis furnace; feeding spiral blades are arranged on the rotating shaft located in the feeding furnace, and pyrolysis spiral blades are arranged on the rotating shaft located in the pyrolysis furnace;

[0012] A labyrinth air duct is arranged inside the square top of the pyrolysis furnace. The labyrinth air duct is bent in an S shape and overlaps in multiple layers along the up and down directions. The extending direction of a single layer of the labyrinth air duct is parallel to the top wall of the pyrolysis furnace.

[0013] Optionally, an inner shaft channel is opened in the rotating shaft, and the inner shaft channel penetrates through the end face of the tail end of the rotating shaft and extends to near the head end of the rotating shaft; a plurality of carrier gas inlets are opened on the rotating shaft located in the feeding furnace, and the carrier gas inlets are arranged at intervals and are all communicated with the feeding furnace and the inner shaft channel.

[0014] Optionally, the carrier gas inlets are arranged at intervals along the spiral gaps of the feeding spiral blades and alternate up and down in the inner shaft channel; the interval between adjacent carrier gas inlets on the same generatrix of the rotating shaft is the same as the pitch of the feeding spiral blades.

[0015] Optionally, a pyrolysis gas inlet communicated with the pyrolysis furnace is provided at the bottom of the labyrinth air duct, and a pyrolysis gas outlet is provided at the top of the labyrinth air duct; the pyrolysis gas outlet is connected to an induced draft air pump; a catalyst loading port is provided at the head end of the square top of the pyrolysis furnace, and a catalyst unloading port is provided at the tail end of the square top of the pyrolysis furnace;

[0016] And / or, a plurality of upper and lower partition plates are arranged at intervals in the vertical direction along the inner edge of the square top of the pyrolysis furnace. The plurality of upper and lower partition plates are all parallel to the top wall of the pyrolysis furnace and include a plurality of front connecting plates and a plurality of rear connecting plates; the front end of the front connecting plate is fixedly installed on the front side wall of the square top of the pyrolysis furnace, and there is a gap between the rear end of the front connecting plate and the rear side wall of the square top of the pyrolysis furnace; the rear end of the rear connecting plate is fixedly installed on the rear side wall of the square top of the pyrolysis furnace, and there is a gap between the front end of the rear connecting plate and the front side wall of the square top of the pyrolysis furnace; any one of the rear connecting plates is located between two adjacent front connecting plates to form the labyrinth air channel bent in an S shape inside the square top of the pyrolysis furnace.

[0017] Optionally, the height of the end is 0.3 - 0.7 times the diameter of the circle, and the height of the head end is 1.2 - 1.5 times the height of the end;

[0018] And / or, in the cross-section of the pyrolysis furnace, the number of the labyrinth air channels arranged in the horizontal direction is 6 - 8, the number of layers of bending and overlapping of each labyrinth air channel in the vertical direction is 4 - 6, the width of each labyrinth air channel in the horizontal direction is 50 - 150 mm, and the height of each layer is 50 - 150 mm.

[0019] Optionally, the pitch of the feed screw blade is 3 - 5 times the pitch of the pyrolysis screw blade.

[0020] Optionally, the gap between the outer edge of the feed screw blade and the inner wall of the feed furnace is 1 - 3 mm; the gap between the outer edge of the pyrolysis screw blade and the lower inner wall of the pyrolysis furnace is 1 - 3 mm.

[0021] Optionally, a rotary feeder valve is arranged inside the feed pipe of the feeding device, and the gap between the outer edge of the rotary feeder valve and the inner wall surface of the feeding device is less than 1 mm; a rotary discharge valve is arranged inside the discharge pipe of the discharging device, and the gap between the outer edge of the rotary discharge valve and the inner wall surface of the discharging device is less than 1 mm.

[0022] Optionally, independent temperature control devices are respectively arranged inside the inner channel of the shaft, on the furnace wall of the square top of the pyrolysis furnace, and on the furnace wall of the circular main body of the pyrolysis furnace. The temperature range inside the inner channel of the shaft is 400 - 600 °C, the temperature range of the furnace wall of the circular main body of the pyrolysis furnace is 400 - 600 °C, and the temperature range of the furnace wall of the square top of the pyrolysis furnace is 600 - 800 °C.

[0023] Furthermore, the present invention also provides a pyrolysis method, which is implemented based on the above-mentioned biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air channel, and includes the following steps:

[0024] S1. Add biochar catalyst into the maze air duct; heat the inner channel of the shaft, the furnace wall of the square top of the pyrolysis furnace, and the furnace wall of the circular main body of the pyrolysis furnace to the set temperature respectively, rotate the rotating shaft at a constant speed according to the set rotation speed, and the rotation speed of the rotating shaft is 5 - 15 r / min; introduce inert anaerobic gas into the inner channel of the shaft, and after preheating, enter the feeding furnace through the carrier gas inlet;

[0025] S2. Add raw materials into the feeding furnace from the feeding device. Under the pushing and stirring action of the feeding spiral blades, the raw materials enter the pyrolysis furnace, heat up and undergo catalytic pyrolysis in the pyrolysis furnace to generate pyrolysis gas;

[0026] S3. Turn on the induced air pump. Under the action of the induced air pump, the pyrolysis gas enters the maze air duct, swirls and rotates in the maze air duct, and continuously undergoes catalytic reaction in contact with the catalyst, and finally is discharged through the pyrolysis gas outlet to obtain high - calorific - value bio - gas;

[0027] S4. The char generated after the complete pyrolysis of the raw materials is discharged from the discharging device and collected.

[0028] (III) Beneficial effects

[0029] The technical solution of the present invention provides a biomass pyrolysis gas non - in - situ catalytic device with a maze air duct. By establishing a non - in - situ catalytic maze air duct above the pyrolysis space, the efficiency of tar removal is significantly improved, and the further conversion of tar and carbon dioxide into high - calorific - value bio - gas is promoted. After the biomass raw materials are preheated by high - temperature carrier gas in the feeding furnace, they enter the pyrolysis furnace to undergo pyrolysis reaction. The generated pyrolysis gas enters the maze air duct under the action of the induced air pump. The multi - folded maze air duct makes the pyrolysis gas swirl and rotate in a high - temperature environment and fully contact with the catalyst to undergo catalytic reaction, promoting the conversion of by - products such as tar, and improving the yield and calorific value of the non - condensable gas. In addition, the feeding furnace maintains a positive pressure inside the equipment by evenly arranging the carrier gas inlets to prevent the high - temperature pyrolysis gas generated by the pyrolysis furnace from diffusing into the feeding furnace and coking when cooled. At the same time, a heating device is arranged inside the rotating shaft, avoiding coking due to cold inside the equipment, and improving the pyrolysis efficiency while extending the continuous working time of the reactor.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) High space utilization rate: Eliminate additional auxiliary defocusing equipment, and through high - temperature treatment in the multi - folded maze air duct, significantly reduce the tar in the discharged pyrolysis gas. The device structure is compact, improving the space utilization rate.

[0032] (2) High thermal utilization efficiency: By arranging the maze air duct above the circular main body of the pyrolysis furnace, the overall thermal utilization efficiency of the system is improved, further reducing energy waste and lowering the operating cost.

[0033] (3) High tar removal rate: By means of a complex gas flow path, the reaction time of the gas is prolonged, effectively enhancing the conversion of tar gas and significantly reducing tar by-products.

[0034] (4) Strong equipment stability: The uniformly arranged carrier gas on the rotating shaft and in the feeding furnace ensures the uniform transportation and sufficient pyrolysis of the raw materials. At the same time, it reduces the coking of pyrolysis gas when encountering cold, and prolongs the service life of the equipment.

[0035] (5) Precise process control: By adjusting the structure of the maze air duct and the rotation speed of the rotating shaft, the pyrolysis temperature, reaction time and gas flow rate can be flexibly controlled, so as to achieve efficient treatment of different biomasses and have high process flexibility.

[0036] (6) Good environmental protection performance: The optimized guidance of gas and the reduction of by-products during the pyrolysis process reduce the environmental pollution emissions, meet the environmental protection requirements, and have good environmental friendliness.

[0037] (7) Pressure protection: In the pyrolysis furnace, the rapidly expanding pyrolysis gas can enter the maze air duct under the action of the induced air pump and be discharged orderly, avoiding excessive pressure at the reaction center and affecting the pyrolysis reaction.

[0038] (8) Automatic feeding and slag discharging: The raw materials and the solid carbon remaining after pyrolysis will automatically enter and be discharged under the action of gravity and the rotary feeder (rotary discharge valve), preventing blockage of the pipelines in the furnace body while having high sealing performance. Description of the Drawings

[0039] Figure 1 is a schematic structural diagram of the biomass pyrolysis gas non-in-situ catalytic pyrolysis device with a maze air duct of the present invention;

[0040] Figure 2 is Figure 1 a cross-sectional schematic diagram of the pyrolysis furnace in

[0041]

Description of the Reference Numerals

[0042] 1: Feeding furnace; 11: Feeding device;

[0043] 2: Pyrolysis furnace; 21: Discharging device;

[0044] 3: Rotating shaft; 31: Inner channel of the shaft; 32: Feeding spiral blade; 33: Pyrolysis spiral blade; 34: Carrier gas inlet;

[0045] 4: Maze air duct; 41: Upper and lower partition plates; 42: Pyrolysis gas inlet; 43: Pyrolysis gas outlet; 44: Catalyst loading port; 45: Catalyst unloading port; 46: Induced draft air pump;

[0046] 5: Independent temperature control device. Detailed implementation manners

[0047] For better explaining the present invention for easy understanding, the present invention will be described in detail below with reference to the accompanying drawings through specific implementation manners.

[0048] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0049] In addition, the descriptions such as "first" and "second" in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In the present invention, unless otherwise clearly specified and defined, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" may be a fixed connection, a detachable connection, or integrated; "connection" may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0051] See Figure 1 , the present invention provides a biomass pyrolysis gas non-in-situ catalytic device with a maze air duct, which includes a feeding furnace 1, a pyrolysis furnace 2, a rotating shaft 3, and a maze air duct 4.

[0052] The feeding furnace 1 is a horizontally arranged hollow circular through-tube. At the top of the first end of the feeding furnace 1, a feeding device 11 is provided, and raw materials enter the feeding furnace 1 from the feeding device 11. Among them, the feeding furnace 1 is preferably a hollow circular tube, and the rotary feeder valve arranged in the feeding device 11 is preferably a star valve. Under the action of gravity and the stirring action of the star valve, the raw materials continuously and stably supply to the feeding furnace 1. Preferably, the gap between the outer edge of the rotary feeder valve and the inner wall surface of the feeding device 11 is less than 1 mm, which can ensure the stability of gas and solid inside and outside the feeding furnace 1, and can also cut off the air pressure between the upper and lower parts of the feeding device 11 to play a role of air-lock and sealing.

[0053] The pyrolysis furnace 2 is a horizontally arranged hollow tube, and the end of the feeding furnace 1 and the first end of the pyrolysis furnace 2 are connected through. In the cross-section of the pyrolysis furnace 2, the inner surface contour of the pyrolysis furnace 2 is a contour shape where a circle is connected to a square. The bottom ends of the two equal-length opposite vertical sides of the square are respectively located on the circumference of the circle (see Figure 2 ), and the width of the square (i.e., the bottom side length a) is 0.5 to 1 times the diameter of the circle. Specifically, the pyrolysis furnace 2 is a special-shaped hollow tube composed of an arc wall with an open top, a pair of vertically arranged flat side walls, and a flat top wall at the top. At the bottom of the end of the pyrolysis furnace 2, a discharging device 21 is provided. The mixture of biochar obtained after pyrolysis continuously and stably discharges from the pyrolysis furnace 2 through the discharging device 21 under the stirring action and gravity of the rotary discharging valve. Among them, the rotary discharging valve arranged in the discharging device 21 is preferably a star valve. Preferably, the gap between the outer edge of the rotary discharging valve and the inner wall surface of the discharging device 21 is less than 1 mm, so as to ensure the stability of gas and solid inside and outside the pyrolysis furnace 2, and can also cut off the air pressure between the upper and lower parts of the discharging device 21 to play a role of air-lock and sealing.

[0054] Among them, see Figure 1 , the top wall of the pyrolysis furnace 2 is inclined. In the cross-section of the end of the pyrolysis furnace 2, the height of the square is the end height b, and the end height is less than the diameter of the circle; in the cross-section of the first end of the pyrolysis furnace 2, the height of the square is the first end height c, and the first end height c is greater than the end height b. Among them, in the preferred embodiment, the end height b is 0.3 to 0.7 times the diameter of the circle, and the first end height c is 1.2 to 1.5 times the end height b. The top wall of the pyrolysis furnace 2 gradually slopes downward from the first end to the end. In this way, not only enough pyrolysis space is reserved, but also space is reserved for arranging the maze air duct 4 at the top, which helps to save the device volume and reduce the consumption of energy and resources. At the same time, the top wall of the pyrolysis furnace 2 gradually slopes downward from the first end to the end, with the first end higher than the end, ensuring the inclined arrangement of the maze gas 4, thus facilitating the replacement of the biochar catalyst.

[0055] The rotating shaft 3 is a horizontally arranged cylindrical rotating shaft, which is coaxially arranged in the feeding furnace 1 and extends to the end of the pyrolysis furnace 2. The front end and the end of the rotating shaft 3 are respectively fixed to the front end and the end of the feeding furnace 1 and the pyrolysis furnace 2 through bearings. The feeding screw blade 32 is arranged on the rotating shaft 3 located in the feeding furnace 1, and the pyrolysis screw blade 33 is arranged on the rotating shaft 3 located in the pyrolysis furnace 2. Moreover, an inner shaft channel 31 is provided in the rotating shaft 3, and the inner shaft channel 31 penetrates through the end face of the rotating shaft 3 and extends to near the front end of the rotating shaft 3. At the same time, a plurality of carrier gas inlets 34 are provided on the rotating shaft 3 located in the feeding furnace 1. The carrier gas inlets 34 are arranged at intervals and are all communicated with the furnace body and the inner shaft channel 31. Among them, the carrier gas inlets 34 are arranged at intervals along the spiral gap of the feeding screw blade 32 and alternate up and down in the inner shaft channel 31; the interval between adjacent carrier gas inlets 34 on the same generatrix of the rotating shaft 3 is the same as the pitch of the feeding screw blade 32. The advantage of such an arrangement is that the carrier gas is evenly distributed in the feeding furnace 1, and it is beneficial to maintain the positive pressure of the feeding furnace 1 and prevent the generated pyrolysis gas from diffusing into the feeding furnace 1 and coking when cooled.

[0056] A labyrinth air channel 4 is arranged in the square top of the pyrolysis furnace 2. The labyrinth air channel 4 is bent in an S shape and overlaps in multiple layers along the up and down direction. The extending direction of the single-layer labyrinth air channel 4 is parallel to the top wall of the pyrolysis furnace 2. The labyrinth air channel 4 is helpful for the precise control of the process, can flexibly control the reaction time and gas flow rate of the pyrolysis gas in the labyrinth air channel 4, and has high process flexibility. In addition, the labyrinth air channel 4 is connected to the inside of the pyrolysis furnace 2 through a pyrolysis gas inlet 42. The pyrolysis gas inlet 42 is arranged near the end of the pyrolysis furnace 2 to ensure sufficient pyrolysis of the raw material and extend the residence time of the pyrolysis gas in the high-temperature section of the equipment. A pyrolysis gas outlet 43 is arranged at the top of the labyrinth air channel 4, and the pyrolysis gas outlet 43 is connected to an induced draft air pump 46. Moreover, a catalyst loading port 44 is arranged at the front end of the square top of the pyrolysis furnace 2, and a catalyst unloading port 45 is arranged at the end of the square top of the pyrolysis furnace 2 to facilitate the loading and unloading of the biochar catalyst.

[0057] Through a unique special-shaped reactor structure, the present invention establishes a maze air passage 4 above the pyrolysis space, thereby effectively extending the path of the pyrolysis gas and prolonging the residence time of the reaction gas. Combined with coke catalysis, the removal effect of tar is significantly improved, and the yield and calorific value of the pyrolysis gas are increased. After being preheated by high-temperature carrier gas in the feeding furnace 1, the biomass raw material enters the pyrolysis furnace 2 for catalytic pyrolysis reaction. Under the action of the induced draft air pump 46, the pyrolysis gas is guided into the maze air passage 4 and continuously spirals and rotates in the high-temperature catalytic environment through a series of complex paths and tortuous channels. The pyrolysis gas processed in the maze air passage 4 can obtain fuel gas with high calorific value. At the same time, the feeding furnace 1 maintains a positive pressure in the equipment through evenly arranged carrier gas inlets 34, avoiding the diffusion of high-temperature gas in the pyrolysis furnace 2 into the feeding furnace 1 and preventing the pyrolysis gas in the equipment from coking due to cooling. In summary, through the maze air passage 4 and the specially designed reactor, the present invention ensures that the pyrolysis gas fully reacts in the high-temperature catalytic environment, effectively improves the removal of tar, the yield and calorific value of the pyrolysis gas, and has the advantages of efficient energy utilization, energy conservation and environmental protection.

[0058] In a preferred embodiment, referring again to Figure 1 , a plurality of upper and lower partition plates 41 are arranged at intervals in the vertical direction along the inner edge of the square top of the pyrolysis furnace 2. The upper and lower partition plates 41 include a plurality of front connecting plates ("front" refers to the side close to the feeding device 11, or can also be called the left connecting plate) and a plurality of rear connecting plates ("rear" refers to the side close to the discharging device 21, or can also be called the right connecting plate). The relative two sides of all the upper and lower partition plates 41 in the cross-section of the pyrolysis furnace 2 are connected to the square top of the pyrolysis furnace 2. The front end of the front connecting plate is fixedly installed on the front side wall of the square top of the pyrolysis furnace 2 (described in combination with Figure 1 's orientation, or it can also be described that the left end of the left connecting plate is fixedly installed on the left side wall of the square top of the pyrolysis furnace 2), and there is a gap between the rear end of the front connecting plate and the rear side wall of the square top of the pyrolysis furnace 2; the rear end of the rear connecting plate is fixedly installed on the rear side wall of the square top of the pyrolysis furnace 2 (described in combination with Figure 1 's orientation, or it can also be described that the right end of the right connecting plate is fixedly installed on the right side wall of the square top of the pyrolysis furnace 2), and there is a gap between the front end of the rear connecting plate and the front side wall of the square top of the pyrolysis furnace 2; any one rear connecting plate is located between two adjacent front connecting plates to form a maze air passage 4 with an S-shaped bend in the square top of the pyrolysis furnace 2.

[0059] Moreover, on the cross-section of the pyrolysis furnace 2, the number of maze air channels 4 arranged horizontally is 6 to 8, the number of layers of each maze air channel 4 bent and overlapped in the up-and-down direction is 4 to 6, the width of each maze air channel 4 in the horizontal direction is 50 to 150 mm, and the height of each layer is 50 to 150 mm. Specifically, a plurality of vertical partition plates arranged at intervals in the horizontal direction are provided inside the square top of the pyrolysis furnace 2. Each vertical partition plate is vertically arranged and parallel to the axis direction of the rotating shaft 3. The top end of each vertical partition plate is connected to the top wall of the pyrolysis furnace 2, and the bottom end of each vertical partition plate is connected to the upper and lower partition plate 41 at the lowermost layer. The adjacent two vertical partition plates define the width of the maze air channel 4 in the horizontal direction. The advantages of such an arrangement are as follows. First, by optimizing the width, length, and arrangement of the maze air channel 4, the contact area between the pyrolysis gas and the high-temperature wall surface and the catalyst can be significantly increased, making the tar catalytic reaction more sufficient, reducing the tar residue, and improving the tar removal efficiency, pyrolysis gas yield, and calorific value. Second, the design of the multi-folded maze air channel 4 increases the residence time of the gas, enabling the gas to react in the high-temperature environment for a longer time. This not only helps the decomposition and conversion of tar but also reduces the accumulation of tar in the equipment, thereby significantly increasing the conversion rate of tar. Third, the horizontal arrangement and up-and-down bending and overlapping design of the maze air channel 4 can make the air flow more uniform, avoiding local overheating or coking problems caused by uneven air flow. The uniformly flowing gas helps the comprehensive conversion of tar, prevents the accumulation of tar in the reactor, ensures a higher tar removal rate, and reduces the risk of equipment coking.

[0060] See again Figure 1 In addition, the pitch of the feeding spiral blade 32 is 3 to 5 times that of the pyrolysis spiral blade 33. The larger pitch of the feeding spiral blade 32 helps to reduce the residence time of the material in the feeding furnace 1. While ensuring sufficient preheating of the material, it allows the material to quickly leave the low-temperature section to prevent premature decomposition. The smaller pitch of the pyrolysis spiral blade 33 can extend the residence time of the material in the pyrolysis furnace 2. While ensuring sufficient heat decomposition of the material, it promotes the shaping and graphitization of the pyrolytic carbon, thereby obtaining higher-quality carbon products. In addition, the gap between the outer edge of the feeding spiral blade 32 and the inner wall of the feeding furnace 1 is 1 to 3 mm; the gap between the outer edge of the pyrolysis spiral blade 33 and the lower inner wall of the pyrolysis furnace 2 is 1 to 3 mm, so as to smoothly push the material and prevent the material from getting stuck. There is a gap between the outer edge of the pyrolysis spiral blade 33 and the lower wall surface of the maze air channel 4, so that there is a buffer space for the pyrolysis gas before it enters the maze air channel 4, and a large amount of flue gas generated by pyrolysis will not accumulate and stay at the spiral, thereby reducing the possibility of coking and blockage.

[0061] In a more preferred embodiment, independent temperature control devices 5 are respectively arranged inside the axial channel 31 of the rotating shaft 3, on the furnace wall (specifically, the outer wall surface) of the square top of the pyrolysis furnace 2, and on the furnace wall (specifically, the outer wall surface of the arc wall) of the circular main body of the pyrolysis furnace 2 (see Figure 1 the dashed line in). Among them, the independent temperature control device 5 is preferably an electromagnetic heating system. The temperature inside the axial channel 31 is preferably 400 - 600 °C, the temperature of the arc wall of the pyrolysis furnace 2 is preferably 400 - 600 °C, and the temperature on the furnace wall of the square top of the pyrolysis furnace 2 is preferably 600 - 800 °C. The advantages of such a design are as follows. First, the independent temperature control device 5 arranged inside the axial channel 31 can precisely control the temperature of the carrier gas while heating the rotating shaft 3, improving the thermal efficiency of the pyrolysis reaction, reducing energy waste, and preventing the raw material from coking when entering the pyrolysis furnace. Second, arranging the independent temperature control device 5 on the arc wall of the pyrolysis furnace 2 provides a stable energy source required for the pyrolysis reaction, maintaining a high-temperature environment inside the pyrolysis furnace 2 and ensuring the efficiency and stability of the pyrolysis process. Third, arranging the independent temperature control device 5 on the furnace wall of the square top of the pyrolysis furnace 2 with a higher temperature setting range ensures that the gas can reach the high-temperature environment required for cracking tar when passing through the labyrinth air channel 4.

[0062] Furthermore, the present invention also provides a pyrolysis method, which is implemented based on the above-mentioned biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air channel, and it includes:

[0063] S1. Add a certain amount of biochar catalyst into the labyrinth air channel 4 from the catalyst loading port 44; the axial channel 31, the furnace wall of the square top of the pyrolysis furnace 2, and the furnace wall of the circular main body of the pyrolysis furnace 2 are respectively heated to the set temperature. The rotating shaft 3 rotates uniformly at the set speed driven by the motor, and the rotation speed of the rotating shaft 3 is 5 - 15 r / min; an inert anaerobic gas (for example, one or more of nitrogen, argon, and helium) is introduced into the axial channel 31, and after preheating, it enters the feeding furnace 1 through the carrier gas inlet 34;

[0064] S2. Add raw materials from the feeding device 11. Under the action of gravity and the stirring of the rotary feeder valve, the raw materials enter the feeding furnace 1. Under the pushing and stirring of the feeding spiral blade 32, the raw materials enter the pyrolysis furnace 2 and are heated and catalytically pyrolyzed in the pyrolysis furnace 2 to generate a large amount of pyrolysis gas;

[0065] S3. Turn on the induced draft air pump 46. Under the action of the induced draft air pump 46, the pyrolysis gas enters the labyrinth air channel 4, spirals and turns in the multi-folded labyrinth air channel 4, contacts with the catalyst and continuously undergoes catalytic reactions, and finally is discharged through the pyrolysis gas outlet 43 to obtain high-calorie bio-gas;

[0066] S4. After the raw materials are completely pyrolyzed, the generated carbon is discharged and collected from the discharging device 21 under the combined action of gravity and a rotary discharge valve, and is used as a subsequent biochar catalyst.

[0067] The following details the pyrolysis method using a biomass pyrolysis device with a labyrinth air passage through specific examples. In each example, a device with basically the same structure is used.

[0068] Example 1

[0069] The inner cross-section of the feeding furnace 1 is a circle with a diameter of Φ800 mm and a length of 400 mm; the inner cross-section at the head end of the pyrolysis furnace 2 is a combination of a circle with a diameter of Φ800 mm and a square with a side length of 800 mm × 800 mm, and the inner cross-section at the tail end is a combination of a circle with a diameter of Φ800 mm and a rectangle with a size of 800 mm × 600 mm, with a length of 1000 mm. The shaft diameter of the rotating shaft 3 is 200 mm, the outer diameter of the feeding spiral blade 32 is 797 mm, the pitch is 150 mm, the outer diameter of the pyrolysis spiral blade 33 is 797 m, and the pitch is 50 mm. The inner cross-section of the square top of the pyrolysis furnace 2 is a rectangle with a size of 800 mm × 600 mm. The number of labyrinth air passages 4 arranged horizontally is 8, the number of layers of bending and overlapping in the up and down direction for each labyrinth air passage 4 is 5, the width of a single labyrinth air passage 4 in the horizontal direction is 100 mm, and the height is 120 mm.

[0070] The rotation speed of the rotating shaft 3 is set to 10 r / min, the internal temperature of the inner channel 31 of the rotating shaft 3 is set to 500 °C, the temperature of the arc wall of the pyrolysis furnace 2 is set to 500 °C, the temperature of the furnace wall of the square top of the pyrolysis furnace 2 is set to 800 °C, and biochar catalyst is filled. Using walnut shell as the raw material, under the pushing action of the feeding spiral blade 32, it enters the pyrolysis furnace 2 and undergoes a pyrolysis reaction. The pyrolyzed carbon is discharged through the discharging device 21 under the pushing action of the pyrolysis spiral blade 33, and pyrolyzed carbon with a specific surface area of 77.4 cm 2 / g is obtained after separation and collection. The pyrolysis gas enters the labyrinth air passage 4 under the action of the induced air pump 46. The pyrolysis gas spirals and rotates in the multi-folded labyrinth air passage 4, continuously undergoes a catalytic reaction, and finally is discharged through the pyrolysis gas outlet 43 to obtain high-calorific-value bio-gas with a yield of 68.7 wt% and a calorific value of 19.8 MJ / Nm 3 , effectively improving the removal rate of tar, the yield and calorific value of pyrolysis gas.

[0071] Example 2

[0072] The difference between this embodiment and Embodiment 1 lies in the change of the structure of the pyrolysis furnace 2 and the distribution structure of the labyrinth air channels 4. The inner cross-section at the head end of the pyrolysis furnace 2 is a combination of a circle with a diameter of Φ800mm and a rectangle of 400mm×600mm, and the inner cross-section at the tail end is a combination of a circle with a diameter of Φ800mm and a square of 400mm×400mm, with a length of 1000mm. The inner cross-section of the square top of the pyrolysis furnace 2 is a square of 400mm×400mm. The number of labyrinth air channels 4 arranged horizontally is 8. Each labyrinth air channel 4 is bent and overlapped in the vertical direction for 5 layers. The width of a single labyrinth air channel 4 in the horizontal direction is 50mm, and the height is 80mm.

[0073] The rotation speed of the rotating shaft 3 is set to 15 r / min, the internal temperature of the inner channel 31 of the rotating shaft 3 is set to 400 °C, the temperature of the arc wall of the pyrolysis furnace 2 is set to 600 °C, the temperature of the furnace wall of the square top of the pyrolysis furnace 2 is set to 800 °C, and biochar catalyst is filled. Using pinewood as the raw material, under the pushing action of the feeding spiral blade 32, it enters the pyrolysis furnace 2 and undergoes a pyrolysis reaction. The pyrolytic carbon is discharged through the discharging device 21 under the pushing action of the pyrolysis spiral blade 33, and after separation and collection, pyrolytic carbon with a specific surface area of 72.7 cm 2 / g is obtained. The pyrolysis gas enters the labyrinth air channels 4 under the action of the induced air pump 46. The pyrolysis gas spirals and rotates in the multi-folded labyrinth air channels 4, continuously undergoes a catalytic reaction, and finally is discharged through the pyrolysis gas outlet 43 to obtain high-calorific value biogas with a yield of 66.1 wt% and a calorific value of 19.2 MJ / Nm 3 , effectively improving the removal rate of tar, the yield and calorific value of pyrolysis gas.

[0074] Embodiment 3

[0075] The difference between this embodiment and Embodiment 1 lies in the change of the temperature settings of the rotating shaft 3, the arc wall of the pyrolysis furnace 2, and the furnace wall of the square top of the pyrolysis furnace 2.

[0076] The rotation speed of the rotating shaft 3 is set to 5 r / min, the internal temperature of the inner channel 31 of the rotating shaft 3 is set to 400 °C, the temperature of the arc wall of the pyrolysis furnace 2 is set to 400 °C, the temperature of the furnace wall of the square top of the pyrolysis furnace 2 is set to 600 °C, and biochar catalyst is filled. Using bagasse as the raw material, under the pushing action of the feeding spiral blade 32, it enters the pyrolysis furnace 2 and undergoes a pyrolysis reaction. The pyrolytic carbon is discharged through the discharging device 21 under the pushing action of the pyrolysis spiral blade 33, and after separation and collection, pyrolytic carbon with a specific surface area of 69.7 cm 2Pyrolytic carbon of / g. The pyrolysis gas enters the labyrinth air duct 4 under the action of the induced air pump 46. The pyrolysis gas spirals and rotates in the multi-folded labyrinth air duct 4, continuously undergoes catalytic reactions, and finally is discharged through the pyrolysis gas outlet 43 to obtain high-calorific-value biogas with a yield of 65.5 wt% and a calorific value of 18.9 MJ / Nm 3 , effectively improving the removal rate of tar, the yield and calorific value of the pyrolysis gas.

[0077] It should be understood that the above description of the specific embodiments of the present invention is only for explaining the technical route and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. However, the present invention is not limited to the above specific embodiments. All changes or modifications made within the scope of the claims of the present invention should be covered by the protection scope of the present invention.

Claims

1. A biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air duct, characterized in that It includes a feeding furnace (1), a pyrolysis furnace (2), a rotating shaft (3) and a labyrinth air duct (4); The feeding furnace (1) is a hollow circular through-tube, and a feeding device (11) is provided at the top of the head end of the feeding furnace (1); In the cross-section of the pyrolysis furnace (2), the inner surface contour of the pyrolysis furnace (2) is a contour shape where a circle is connected to a square. The bottom ends of the two equal-length opposite vertical sides of the square are respectively located on the circumference of the circle, and the width of the square is 0.5 to 1 times the diameter of the circle; the top wall of the pyrolysis furnace (2) is inclined; in the cross-section of the tail end of the pyrolysis furnace (2), the height of the square is the tail end height, and the tail end height is less than the diameter of the circle; in the cross-section of the head end of the pyrolysis furnace (2), the height of the square is the head end height, and the head end height is greater than the tail end height; the tail end of the feeding furnace (1) and the head end of the pyrolysis furnace (2) are connected in a through manner; a discharge device (21) is provided at the bottom of the tail end of the pyrolysis furnace (2); The rotating shaft (3) is coaxially arranged inside the feeding furnace (1) and extends to the tail end of the pyrolysis furnace (2); a feeding screw blade (32) is arranged on the rotating shaft (3) inside the feeding furnace (1), and a pyrolysis screw blade (33) is arranged on the rotating shaft (3) inside the pyrolysis furnace (2); A labyrinth air duct (4) is arranged inside the square top of the pyrolysis furnace (2). The labyrinth air duct (4) is bent in an S shape and overlaps in multiple layers in the up and down direction. The extending direction of a single-layer labyrinth air duct (4) is parallel to the top wall of the pyrolysis furnace (2).

2. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to claim 1, characterized in that, An inner shaft channel (31) is opened inside the rotating shaft (3). The inner shaft channel (31) penetrates through the tail end face of the rotating shaft (3) and extends to near the head end of the rotating shaft (3); a plurality of carrier gas inlets (34) are opened on the rotating shaft (3) inside the feeding furnace (1). The carrier gas inlets (34) are arranged at intervals and are all communicated with the feeding furnace (1) and the inner shaft channel (31).

3. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to claim 2, characterized in that, The carrier gas inlets (34) are arranged at intervals along the spiral gap of the feeding screw blade (32) and alternate up and down in the inner shaft channel (31); the interval between adjacent carrier gas inlets (34) on the same generatrix of the rotating shaft (3) is the same as the pitch of the feeding screw blade (32).

4. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air duct according to any one of claims 1-3, characterized in that A pyrolysis gas inlet (42) communicated with the pyrolysis furnace (2) is provided at the bottom of the labyrinth air duct (4), and a pyrolysis gas outlet (43) is provided at the top of the labyrinth air duct (4); the pyrolysis gas outlet (43) is connected to an induced draft air pump (46); a catalyst loading port (44) is provided at the head end of the square top of the pyrolysis furnace (2), and a catalyst discharge port (45) is provided at the tail end of the square top of the pyrolysis furnace (2); And / or, a plurality of upper and lower partition plates (41) are arranged at intervals in the vertical direction along the inner edge of the square top of the pyrolysis furnace (2). The plurality of upper and lower partition plates (41) are all parallel to the top wall of the pyrolysis furnace (2) and include a plurality of front connecting plates and a plurality of rear connecting plates. The front end of the front connecting plate is fixedly installed on the front side wall of the square top of the pyrolysis furnace (2), and there is a gap between the rear end of the front connecting plate and the rear side wall of the square top of the pyrolysis furnace (2). The rear end of the rear connecting plate is fixedly installed on the rear side wall of the square top of the pyrolysis furnace (2), and there is a gap between the front end of the rear connecting plate and the front side wall of the square top of the pyrolysis furnace (2). Any one of the rear connecting plates is located between two adjacent front connecting plates to form the labyrinth air duct (4) bent in an S shape inside the square top of the pyrolysis furnace (2).

5. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-3, characterized in that, The height of the end is 0.3 - 0.7 times the diameter of the circle, and the height of the head is 1.2 - 1.5 times the height of the end; And / or, in the cross-section of the pyrolysis furnace (2), the number of the labyrinth air ducts (4) arranged in the horizontal direction is 6 - 8. The number of layers of each labyrinth air duct (4) bent and overlapped in the vertical direction is 4 - 6. The width of each labyrinth air duct (4) in the horizontal direction is 50 - 150 mm, and the height of each layer is 50 - 150 mm.

6. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-3, characterized in that, The pitch of the feeding spiral blade (32) is 3 - 5 times the pitch of the pyrolysis spiral blade (33).

7. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-3, characterized in that, The gap between the outer edge of the feeding spiral blade (32) and the inner wall of the feeding furnace (1) is 1 - 3 mm; the gap between the outer edge of the pyrolysis spiral blade (33) and the lower inner wall of the pyrolysis furnace (2) is 1 - 3 mm.

8. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-3, characterized in that, A rotary feeder valve is arranged inside the feeding pipe of the feeding device (11), and the gap between the outer edge of the rotary feeder valve and the inner wall surface of the feeding device (11) is less than 1 mm; a rotary discharging valve is arranged inside the discharging pipe of the discharging device (21), and the gap between the outer edge of the rotary discharging valve and the inner wall surface of the discharging device (21) is less than 1 mm.

9. The biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-3, characterized in that, Independent temperature control devices (5) are respectively arranged inside the shaft inner channel (31), on the furnace wall of the square top of the pyrolysis furnace (2), and on the furnace wall of the circular main body of the pyrolysis furnace (2). The temperature range inside the shaft inner channel (31) is 400 - 600 °C, the temperature range of the furnace wall of the circular main body of the pyrolysis furnace (2) is 400 - 600 °C, and the temperature range of the furnace wall of the square top of the pyrolysis furnace (2) is 600 - 800 °C.

10. A pyrolysis method, which is implemented based on the biomass pyrolysis gas non-in-situ catalytic device with a labyrinth air passage according to any one of claims 1-9, characterized in that, The pyrolysis method includes the following steps: S1. Add biochar catalyst into the maze air duct (4); heat the inside of the inner shaft channel (31), the furnace wall of the square top of the pyrolysis furnace (2), and the furnace wall of the circular main body of the pyrolysis furnace (2) to the set temperature respectively, rotate the rotating shaft (3) at a constant speed according to the set rotation speed, and the rotation speed of the rotating shaft (3) is 5 - 15 r / min; introduce inert anaerobic gas into the inner shaft channel (31), and after preheating, enter the feeding furnace (1) through the carrier gas inlet (34); S2. Add raw materials into the feeding furnace (1) from the feeding device (11). Under the pushing and stirring action of the feeding spiral blade (32), the raw materials enter the pyrolysis furnace (2), heat up and undergo catalytic pyrolysis in the pyrolysis furnace (2) to generate pyrolysis gas; S3. Turn on the induced draft air pump (46). The pyrolysis gas enters the maze air duct (4) under the action of the induced draft air pump (46), spirals and rotates in the maze air duct (4), contacts with the catalyst and continuously undergoes catalytic reaction, and finally is discharged through the pyrolysis gas outlet (43) to obtain high - calorific value biogas; S4. The carbon generated after the complete pyrolysis of the raw materials is discharged from the discharging device (21) and collected.

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