Shockwave cyclone reactor and method for biomass flash pyrolysis

Abstract

This invention discloses a shockwave cyclone reactor and method for biomass flash pyrolysis. The reactor is a tubular structure and includes at least: a shockwave preheating section, which includes a tubular shell and a rotating shaft disposed within the shell, with a circumferential gap between the rotating shaft and the tubular shell forming a gas channel; the gas channel is provided sequentially along the gas flow direction by: a first stator for initial acceleration of the process gas, a rotor for accelerating the process gas to supersonic speed, and a second stator for generating shockwave losses and rapidly raising the temperature of the process gas; a biomass particle inlet is located downstream of the shockwave preheating section and arranged tangentially along the circumference of the tubular reactor, for mixing the biomass particles with the shockwave-heated gas; guide vanes for forming a cyclone are provided between the biomass particle inlet and the shockwave preheating section; a pyrolysis section is located below the biomass particle inlet and includes a cylindrical section and a conical section; the biomass particles and high-temperature gas form a cyclone in the cylindrical section, pyrolysis is performed in the cyclone state, and gas-solid separation is performed in the conical section.

Description

Technical Field

[0001] This invention relates to the field of biomass pyrolysis for bio-oil production technology, and particularly to a shock wave vortex device and method for biomass flash pyrolysis. Background Technology

[0002] In the production of bio-oil from biomass, conventional equipment commonly used in existing technologies includes falling bed and spiral bed systems. During the production process, pyrolysis time is a critical factor. When the pyrolysis time is too long, long-chain heavy components are prone to coking and polymerization into solids, reducing the oil yield. In addition, conventional equipment relies on the gravity of the particles themselves and the spiral rotation speed, resulting in slow gas-solid movement and low throughput, which also restricts further scale-up of the process. At the same time, conventional equipment relies on electric heating or partial combustion oxidation of the raw materials for heating, resulting in uneven gas-solid heating and a slow heating rate. Local overheating can easily cause the bio-oil to decompose into low-quality small molecule substances, such as methane and carbon monoxide, further reducing the oil yield.

[0003] For example, Chinese patent application CN116622399A discloses a method and apparatus for producing hydrocarbon-rich bio-oil through graded upgrading of biomass. This includes using a solid heat carrier as a primary upgrading catalyst to heat and catalyze biomass for pyrolysis and ketylation and aldol condensation reactions of the gaseous products from the primary pyrolysis, thereby increasing the bio-oil yield while adsorbing and capturing dust, alkali metals, and alkaline earth metals from the gaseous products of the primary pyrolysis. It also includes using a solid heat carrier as a secondary upgrading catalyst to subsequently deoxygenate and reform the gaseous products after primary catalytic upgrading into high-octane hydrocarbons, improving the quality of the bio-oil. This type of scheme uses a conventional moving bed reactor, where the gas-solid movement speed is slow (relying solely on the gravity of the particles), and the pyrolysis still employs traditional heating methods, resulting in uneven heating of the gas and solid components and a slow heating rate.

[0004] Shock waves demonstrate unique advantages for gas heating. First, through shock wave loss phenomena, uniform heating of the gas can be achieved within microseconds, ensuring the reaction occurs entirely at the set temperature. Second, shock wave heating of gas does not require consideration of the heating wall's temperature tolerance, resulting in a high upper temperature limit for the heated gas; it can be considered a "microwave oven" for gas. The inventors have discovered that shock wave pyrolysis is a relatively ideal endogenous heat-generating rapid pyrolysis technology, suitable for high-temperature, short-continuity scenarios. However, the complexity of the shock wave generator's structure makes it difficult to apply in gas-solid two-phase reaction scenarios, as solid particles and tar droplets can collide with the shock wave generator, severely impacting reactor lifespan and operational safety.

[0005] Therefore, there is an urgent need for a shockwave cyclone reactor and method for biomass flash pyrolysis, which can decouple the shockwave heating process from the feedstock reaction process, effectively avoiding the problem that the biomass pyrolysis time is too long and the local heating is uneven, thus affecting the subsequent bio-oil yield.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a shock wave vortex reactor and method for biomass flash pyrolysis. The reactor is configured as a tube, and the gas is heated separately by the shock wave in the shock wave preheating section. Then, the heated high-speed gas is mixed with biomass particles and pyrolyzed in the vortex state in the pyrolysis section. This not only avoids the damage that may be caused by solid particles contacting the shock wave generating device, but also effectively shortens the pyrolysis time and avoids the problem of uneven local heating.

[0008] To achieve the above objectives, according to a first aspect of the present invention, a shock vortex reactor for biomass flash pyrolysis is provided. The reactor is generally tubular in structure and includes at least: a shock preheating section, which includes a tubular shell and a rotating shaft disposed within the shell, the circumferential gap between the rotating shaft and the tubular shell forming a gas channel; the gas channel is provided sequentially along the gas flow direction by: a first stator for initial acceleration of the process gas, a rotor for accelerating the process gas to supersonic speed, and a second stator for generating shock wave losses and rapidly raising the temperature of the process gas; a biomass particle inlet is disposed downstream of the shock preheating section and tangentially arranged along the circumference of the tubular reactor for mixing the biomass particles with the gas heated by the shock wave; guide vanes for forming a vortex are provided between the biomass particle inlet and the shock preheating section; a pyrolysis section is disposed below the biomass particle inlet and includes a cylindrical part and a conical part; the biomass particles and the high-temperature gas form a vortex in the cylindrical part, pyrolysis is performed in the vortex state, and gas-solid separation is performed in the conical part.

[0009] Furthermore, in the above technical solution, the first stator can be fixed on the inner wall of the housing and is composed of multiple radially extending curved first grid blades; the rotor can be fixed on the rotating shaft and is composed of multiple radially extending curved second grid blades, and the rotor is located at an adjacent position downstream of the first stator airflow; the second stator can be fixed on the inner wall of the housing and is composed of multiple radially extending curved third grid blades, and the second stator is located at an adjacent position downstream of the rotor airflow.

[0010] Furthermore, in the above technical solution, the bending directions of the first and third grid blades at corresponding positions are the same, while the bending directions of the first and second grid blades at corresponding positions are opposite.

[0011] Furthermore, in the above technical solution, the gas channel constructed by the first grid leaf is a tapered structure; the gas channel constructed by the second grid leaf is the narrowest in the middle and gradually expands towards both ends; and the gas channel constructed by the third grid leaf is a gradually expanding structure.

[0012] Furthermore, in the above technical solution, the blade profile parameters of the first, second, and third grating blades can be set according to the process gas heating temperature requirements.

[0013] Furthermore, in the above technical solution, the height-to-diameter ratio of the cylindrical part of the pyrolysis section can be set according to the pyrolysis time of the biomass particles.

[0014] Furthermore, in the above technical solution, the end of the cone-shaped part of the pyrolysis section is a solid particle discharge port, which can be used to discharge or recycle the residual carbon particles after the biomass pellets are pyrolyzed.

[0015] Furthermore, in the above technical solution, the guide vane can be fixed on the inner wall of the housing and is composed of multiple radially extending curved fourth grating vanes.

[0016] Furthermore, in the above technical solution, there can be two or more biomass pellet inlets, which are evenly spaced along the circumference of the shell.

[0017] Furthermore, in the above technical solution, the reactor is equipped with a bio-oil outlet pipe. The upper part of the bio-oil outlet pipe passes through the rotating shaft of the shock wave preheating section at the center and extends from the top of the reactor. The lower part extends to the top of the conical part of the pyrolysis section. It is used to discharge the produced gaseous crude bio-oil product and can also be used to provide an annular spiral descent space for biomass particles in the pyrolysis process. A cylindrical metal mesh can be provided below the bio-oil outlet pipe to filter ash particles and residual carbon particles entrained in the gaseous bio-oil.

[0018] To achieve the above objectives, according to a second aspect of the present invention, the present invention provides a shock wave swirling method for biomass flash pyrolysis, employing the aforementioned reactor, and comprising at least the following steps: A. Process gas is introduced as a carrier gas into the shock wave preheating section, and the process gas is accelerated to supersonic speed by the rotor after initial acceleration by the first stator; B. The supersonic process gas generates shock wave losses in the second stator, the temperature of the process gas is rapidly increased, and the velocity is reduced; C. Subsonic high-temperature gas forms a swirling flow at the outlet of the second stator, and the gas in the swirling state mixes with biomass particles tangentially entering the reactor; D. The high-speed gas-solid mixture rotates downward along the inner wall of the cylindrical part of the pyrolysis section, and the biomass particles are pyrolyzed in the swirling state, the crude bio-oil product is discharged into the gas phase through the bio-oil outlet pipe for the next step of catalytic reforming, and the gas-solid mixture undergoes gas-solid separation in the conical part.

[0019] Furthermore, in the above technical solution, the method may also include: E. Solid residual carbon particles are discharged from the bottom outlet; in the case of incomplete pyrolysis of residual carbon particles, cyclic pyrolysis is carried out.

[0020] Furthermore, in the above technical solution, the temperature of the process gas in step B can be rapidly raised to 500-550℃.

[0021] Furthermore, in the above technical solution, the residence time of biomass pellets in the pyrolysis section can be 0.5-1 second.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The apparatus and method of this invention can be applied to the process of producing bio-oil (or producing oil from low-quality fuels such as pulverized coal and lignite) through biomass pyrolysis. The inventors have discovered that during biomass pyrolysis using shock wave heating, the shock wave heating and endothermic reaction are not completed simultaneously. The rate of shock wave heating > the rate of endothermic gas-phase reaction > the rate of endothermic gas-solid reaction; that is, shock wave heating can be completed instantaneously (in microseconds). This provides a theoretical basis for decoupling the shock wave heating process from the raw material pyrolysis reaction. Based on this, this invention places the biomass feed inlet in the gas channel after shock wave heating, which not only does not affect the pyrolysis efficiency but also effectively avoids the impact of solid particles and tar droplets on the shock wave generating device.

[0024] 2) This invention, by setting a shock wave preheating section in a tubular reactor including a first stator, a rotor, and a second stator, generates a shock wave effect in the process gas during the operation of the gas channel. The gas is initially accelerated at the first stator, and the rotation of the rotor accelerates the raw gas to supersonic speed. Then, shock wave loss is generated at the second stator, and the temperature of the process gas is instantly raised, thereby achieving the purpose of rapid and uniform heating of the process gas. Compared with the traditional heating method, this invention avoids the decrease in oil quality and yield caused by partial biomass combustion heating through air introduction, while accelerating the heating speed and avoiding the problems of slow heating speed and uneven gas heating caused by external heating of process gas in furnace tubes.

[0025] 3) This invention places the biomass pellet inlet downstream of the shock wave preheating section, decoupling the shock wave heating from the biomass pellet pyrolysis and successfully applying shock wave technology to the gas-solid two-phase field. Through the combination of guide vanes and the tangential orientation of the biomass pellet inlet, a high-speed, high-temperature airflow carries the biomass pellets downwards along the inner wall of the pyrolysis chamber. Pyrolysis occurs in the cylindrical section under swirling flow, followed by gas-solid separation in the conical section. This significantly shortens the gas-solid contact time, reduces the coking and polymerization reaction of long-chain heavy components, and effectively improves the bio-oil yield. Simultaneously, the gas-solid flow is a swirling flow with constantly changing direction, periodically altering the velocity difference between gas and solid, achieving a high-speed, strongly coupled swirling process. This provides a large amount of heat for the pyrolysis of biomass pellets in a short time, increasing the rate of volatile release and further improving the bio-oil yield.

[0026] 4) The preheating stage of this invention is only for gases, enabling the process gas to have a "high temperature and short residence time" in the shock wave preheating section. This internal heat generation method makes the gas temperature higher than the temperature of the wall surface of the shock wave preheating section of the tubular reactor. Compared with existing furnace tubes, the existence of the boundary layer between the tube wall and the gas changes from a negative effect that hinders heat transfer to a positive effect that protects the furnace tube. Therefore, when using the same materials, the reactor of this invention can withstand higher temperatures and provide more heat for the pyrolysis reaction. The "short residence time" can create conditions for decoupling shock wave heating and biomass pyrolysis, realizing "heating the gas first, and then mixing the gas and solid for the pyrolysis of biomass particles".

[0027] 5) This invention uses high-speed airflow to carry particles into the pyrolysis section for cyclone pyrolysis. When the throughput is large, it solves the problem that conventional devices rely on the particle's own gravity and the spiral speed, resulting in slow gas-solid movement and low throughput, which helps to scale up the process.

[0028] 6) This invention uses electricity (i.e., electrifying the rotor to create a shock wave effect) instead of fossil fuels to achieve the high temperatures required in the production process. Compared with combustion heating technology, it can reduce carbon dioxide emissions, and the saved fuel can be used to prepare high value-added products or as raw materials.

[0029] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0030] Figure 1 This is a three-dimensional perspective view of the shockwave vortex reactor of the present invention.

[0031] Figure 2This is a schematic cross-sectional view of the shock wave vortex reactor of the present invention (showing the structural composition of the shock wave preheating section).

[0032] Figure 3 This is a three-dimensional structural diagram of the shell at the shock wave preheating section of the present invention (showing the first stator and the second stator fixed on the shell).

[0033] Figure 4 This is a three-dimensional structural schematic diagram of the hollow rotating shaft in the shock wave preheating section of the present invention (showing the rotor fixed on the hollow rotating shaft).

[0034] Figure 5 This is a schematic diagram of the overall structure of the first stator in the shock wave preheating section of the present invention (showing the first grid blade).

[0035] Figure 6 This is a schematic diagram of the overall rotor structure in the shock wave preheating section of the present invention (showing the second grid blade).

[0036] Figure 7 This is a schematic diagram of the overall structure of the second stator in the shock wave preheating section of the present invention (showing the third grid blade).

[0037] Figure 8 This is a schematic diagram of the blade cascades of the first stator, rotor, and second stator in the shock wave preheating section of the present invention (showing the air profile parameter data of each blade cascade).

[0038] Figure 9 This is a schematic diagram of the particle trajectory when the present invention uses a reactor with a diameter of 0.4 meters and a height-to-diameter ratio of 7.5 (with a time interval of 0.1 seconds).

[0039] Figure 10 This is a schematic diagram of the particle trajectory when the present invention uses a reactor with a diameter of 0.4 meters and a height-to-diameter ratio of 10 (time interval is 0.1 seconds).

[0040] Figure 11 This is a schematic diagram of the particle trajectory (time interval is 0.1 seconds) when the reactor has a diameter of 0.4 meters and a height-to-diameter ratio of 12.5.

[0041] Explanation of key figure labels:

[0042] 100 - Shockwave reactor; 101 - Gas inlet for preheating section; 102 - Biomass pellet inlet; 103 - Bio-oil outlet;

[0043] 1-Shock wave preheating section, 10-Shell, 11-Hollow rotating shaft, 12-Gas passage, 13-First stator, 131-First grid blade, 14-Rotor, 141-Second grid blade, 15-Second stator, 151-Third grid blade, 16-Guide blade, 2-Pyrolysis section, 21-Cylindrical part, 22-Conical part, 23-Discharge port. Detailed Implementation

[0044] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0045] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0046] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0047] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0048] The inventors discovered that shock wave heating has unique advantages in heating gases, enabling uniform heating and achieving high temperatures. However, in the process of producing bio-oil (or oil from low-quality fuels such as pulverized coal and lignite) through biomass pyrolysis, since the biomass feedstock is composed of solid particles, if a gas-solid mixture is introduced into the shock wave generator while biomass pyrolysis is occurring simultaneously with shock wave heating, the high gas velocity (nearly supersonic) causes significant impact from the solid particles carried in the gas on the shock wave generator. Specifically, biomass solid particles and small tar droplets generated can collide with the shock wave generator, severely affecting its lifespan and operational safety. Further research by the inventors revealed that during biomass pyrolysis using shock wave heating, the shock wave heating and endothermic reaction are not simultaneous. The rate of shock wave heating > the rate of endothermic gas-phase reaction > the rate of endothermic gas-solid reaction. This means that shock wave heating can be completed instantaneously (on the microsecond scale), providing a theoretical basis for decoupling the shock wave heating process from the feedstock pyrolysis reaction. Therefore, the present invention places the biomass feed inlet in the gas channel after shock wave heating, which not only does not affect the pyrolysis efficiency, but also effectively avoids the impact of solid particles and tar droplets on the shock wave generating device.

[0049] like Figures 1 to 4 As shown, this invention provides a shockwave cyclone reactor 100 for biomass flash pyrolysis (the reactor is generally tubular in structure, but can also be used to produce oil from low-quality fuels such as pulverized coal and lignite), comprising at least a shockwave preheating section 1 and a pyrolysis section 2. The shockwave preheating section 1 (i.e., the shockwave generating device of this invention) includes a tubular shell 10 and a rotating shaft 11 disposed within the shell 10 (the rotating shaft is hollow and can accommodate the bio-oil outlet pipe of this invention). The circumferential gap between the rotating shaft 11 and the shell 10 forms a gas channel 12. Along the gas flow direction, the gas channel 12 is sequentially provided with: a first stator 13 for initial acceleration of the process gas, a rotor 14 for accelerating the process gas to supersonic speed, and a second stator 15 for generating shockwave losses and rapidly raising the temperature of the process gas. The biomass particle inlet 102 is located downstream of the shockwave preheating section and is arranged tangentially along the circumference of the tubular reactor 100, for mixing the biomass particles with the shockwave-heated gas. A guide vane 16 for forming a swirling flow is provided between the biomass pellet inlet 102 and the shock wave preheating section 1. The pyrolysis section 2 is located below the biomass pellet inlet 102 and includes a cylindrical section 21 and a conical section 22. The biomass pellets and high-temperature gas form a swirling flow in the cylindrical section 21, and pyrolysis is carried out in the swirling flow state. Gas-solid separation is carried out in the conical section 22.

[0050] In the above-described technical solution of the present invention, by setting a shock wave preheating section in a tubular reactor including a first stator, a rotor, and a second stator, the process gas (preferably nitrogen) generates a shock wave effect during the operation of the gas channel. It is initially accelerated at the first stator, and the rotation of the rotor accelerates the raw material gas to supersonic speed. This results in shock wave loss at the second stator, instantly raising the temperature of the process gas, thereby achieving rapid and uniform heating of the process gas. Compared to traditional heating methods, this avoids the decrease in oil quality and yield caused by partial biomass combustion heating with air, while simultaneously accelerating the heating rate and avoiding the problems of slow heating and uneven gas heating caused by externally heating the process gas through the furnace tube. Furthermore, by placing the biomass pellet inlet downstream of the shock wave preheating section, the shock wave heating and biomass pellet heating are combined. Particle-to-pyrolysis decoupling successfully applies shock wave technology to the gas-solid two-phase field, avoiding the impact of solid particles and tar droplets on the stator and rotor without affecting subsequent pyrolysis efficiency. Furthermore, the combination of guide vanes and tangential placement of the biomass particle inlet allows a high-speed, high-temperature gas flow carrying biomass particles to swirl downwards along the inner wall of the pyrolysis section. Pyrolysis occurs in the cylindrical section under swirling flow conditions, followed by gas-solid separation in the conical section. This significantly shortens the gas-solid contact time, reduces the coking and polymerization reactions of long-chain heavy components, and effectively improves bio-oil yield. Simultaneously, the swirling gas-solid flow, with its constantly changing direction and periodically altering velocity differences, achieves a high-speed, strong coupling process, providing a large amount of heat for biomass particle pyrolysis in a short time, increasing the rate of volatile release and further improving bio-oil yield.

[0051] Further as Figures 1 to 8 As shown, the first stator 13 is fixed to the inner wall of the housing 10 and is composed of multiple radially extending curved first grating blades 131. The fixing method can be to insert the first grating blades 131 into the housing 10 and lock them in place. The rotor 14 is fixed to the rotating shaft 11 and is composed of multiple radially extending curved second grating blades 141. The fixing method can be to insert the second grating blades 141 into the rotating shaft 11 and lock them in place. The rotor is located downstream of the first stator 13 and adjacent to it. The second stator 15 is fixed to the inner wall of the housing 10 and is composed of multiple radially extending curved third grating blades 151. The second stator 15 is located downstream of the rotor 14 and adjacent to it.

[0052] Further as Figures 3 to 8As shown, the first blade 131 and the third blade 151 at corresponding positions have the same bending direction, while the first blade 131 and the second blade 141 at corresponding positions have opposite bending directions. That is, the first blade 131, the second blade 141, and the third blade 151 are smoothly connected, facilitating rapid airflow. Furthermore, the gas channel constructed by the first blade 131 is a tapered structure (i.e., purely contractile); the gas channel constructed by the second blade 141 is a structure that is narrowest in the middle and gradually expands towards both ends (i.e., impingement type); and the gas channel constructed by the third blade 151 is a gradually expanding structure (i.e., purely expanding type). This structural arrangement is more conducive to the occurrence of shock wave loss effects at the second stator (the principle of shock wave generation is prior art and will not be detailed here). Preferably, but not limitingly, the blade profile parameters of the first blade 131, the second blade 141, and the third blade 151 of the present invention are set according to the heating temperature of the process gas. The rotor 14 has the same width at both ends as the adjacent first stator 13 and second stator 15, and its height is preferably 70mm for both ends. Figure 8 The stator and rotor are planar unfolded structures. Table 1 shows the air profile parameters of the stator and rotor (parameter data are already labeled in...). Figure 8 middle).

[0053] Table 1 Leaf type parameters

[0054]

[0055] After the shock wave loss effect is completed at the second stator 15 (that is, the gas suddenly decelerates through the gradual expansion structure of the second stator, while the supersonic gas from the rotor 14 behind it still maintains high speed and generates shock wave loss), the mixed gas is rapidly heated and the temperature rises, which can achieve the effect of uniform heating.

[0056] Further as Figure 1 , 2 As shown, the height-to-diameter ratio of the cylindrical section 21 in the pyrolysis section can be set according to the pyrolysis time of the biomass pellets. That is, the residence time is determined by setting the number of rotations of the pellets in the pyrolysis chamber based on the height-to-diameter ratio of the cylindrical section. (Reference) Figures 9 to 11 Under different aspect ratios (7.5, 10, and 12.5) in a 0.4m diameter reactor, the particle trajectories are as follows: Figures 9 to 11 As shown (time interval 0.1s). The end of the cone-shaped section 22 of the pyrolysis section is the solid particle outlet 23, which is used to discharge or recycle the residual carbon particles after the biomass pellets are pyrolyzed. That is, the outlet 23 is used to discharge the solid residual carbon particles, collect the residual carbon particles, and the collected solid particles can be mixed back into the silo for secondary pyrolysis of particles that have not been completely decomposed of volatile matter.

[0057] Further as Figure 1 , 2As shown, the guide vane 16 is positioned above the pyrolysis section to guide the airflow in a swirling motion within the pyrolysis section. It can be fixed to the inner wall of the shell at the junction of the pyrolysis section 2 and the shock wave preheating section 1, and is composed of multiple radially extending curved fourth grating blades. The gas channel constructed by the fourth grating blades can be a curved and inclined structure with a fixed value (specific preferred data can be found in Table 1 above), with an angle greater than 45° to the vertical direction, which can be determined based on the number of rotations of the gas-solid fluid.

[0058] Further as Figure 1 , 2 As shown, there can be two or more biomass pellet inlets 102 (preferably two as shown in the figure), and they are evenly spaced along the circumference of the shell 10. Further, the reactor 100 is provided with a bio-oil outlet pipe 103. The upper part of the bio-oil outlet pipe 103 passes through the hollow rotating shaft 11 of the shock wave preheating section 1 at its axis and extends from the top of the reactor 100. The lower part extends above the conical portion 22 of the pyrolysis section 2, for discharging the produced gaseous crude bio-oil product. It should be noted that since the bio-oil outlet pipe 103 is basically continuous within the reactor, in addition to serving as an outlet for the gaseous product, its outer wall and the inner wall of the shell 10 can provide an annular spiral descent space for the biomass pellets during the pyrolysis process. A cylindrical metal mesh (not shown in the figure) can be provided below the bio-oil outlet pipe 103 to filter ash particles and residual carbon particles entrained in the gaseous bio-oil.

[0059] refer to Figures 1 to 11 As shown, the present invention also provides a shock vortex method for biomass flash pyrolysis, the apparatus of which includes at least the following steps:

[0060] Step S101: Process gas (preferably nitrogen) is introduced into the shock wave preheating section 1 as a carrier gas. After the process gas is initially accelerated by the first stator 13, it is accelerated to supersonic speed by the rotor 14.

[0061] In step S102, the supersonic process gas generates shock wave loss at the second stator 15, rapidly increasing its temperature and decreasing its velocity. The temperature of the process gas in this invention can be rapidly increased to 500-550°C.

[0062] In step S103, the subsonic high-temperature gas forms a swirling flow at the outlet of the second stator 15, and the gas in the swirling state mixes with the biomass particles that enter the reactor tangentially.

[0063] In step S104, the high-speed gas-solid mixture rotates downwards along the inner wall of the cylindrical portion 21 of the pyrolysis section 2, and the biomass particles undergo pyrolysis in a swirling state. The residence time of the biomass particles in the pyrolysis section 2 is preferably 0.5-1 seconds. The crude bio-oil product is discharged into the gas phase through the bio-oil outlet pipe 103 for the next step of catalytic reforming, while the gas-solid mixture undergoes gas-solid separation in the conical portion 22.

[0064] The method of the present invention may further include:

[0065] In step S105, solid residual carbon particles are discharged from the bottom outlet 23. If the residual carbon particles are not completely pyrolyzed, cyclic pyrolysis can be carried out, that is, the collected solid particles can be mixed back into the silo to perform secondary pyrolysis on the particles that have not been completely desorbed of volatile matter.

[0066] The preheating stage of the method of this invention is only for gases, which can achieve "high temperature and short residence time" for process gases. First, the requirement of "high temperature" means that the highest temperature of the gas in the shock wave preheating section is about 100-300°C higher than the outlet temperature of a conventional tubular furnace with similar raw materials. This is also one of the main advantages of this invention. In the case of internal heat generation, the gas temperature is higher than the furnace tube temperature, while the temperature of a conventional flue gas thermal radiation furnace tube is higher than the gas temperature inside the tube. The existence of the boundary layer between the tube wall and the gas changes from a negative effect that hinders heat transfer to a positive effect that protects the furnace tube. Therefore, when using furnace tubes of the same material, the reactor of this invention can withstand higher temperatures, providing more heat for the pyrolysis reaction and increasing the yield of bio-oil. Second, "short residence time" refers to a short residence time, which creates conditions for decoupling shock wave heating and biomass pyrolysis, realizing "heating the gas first, and then mixing the gas and solid for the pyrolysis of biomass particles", without affecting the pyrolysis efficiency.

[0067] In addition, the method of the present invention carries particles into the pyrolysis section through high-speed airflow for cyclone pyrolysis. When the throughput is large, it solves the problem that conventional devices rely on the gravity of the particles themselves and the rotation speed of the spiral, resulting in slow gas-solid movement and low throughput, which is conducive to the scale-up of the process. The present invention uses electricity (i.e., electrifying the rotor to generate a shock wave effect) instead of fossil fuels to achieve the high temperature required in the production process. Compared with combustion heating technology, it can reduce carbon dioxide emissions, and the fuel saved can be used to prepare high value-added products or as raw materials.

[0068] The effects of the present invention are illustrated below with several specific embodiments:

[0069] Example 1

[0070] Room temperature nitrogen gas is initially accelerated at the first stator 13, and the rotation of the rotor 14 accelerates the gas to supersonic speed. This generates shock wave loss at the second stator 15, instantly raising the gas temperature to 500-550℃. The heated gas undergoes pulsating mixing in the space between the second stator 15 and the guide vanes 16, resulting in a more uniform gas temperature. Biomass pellets (pine waste) enter the pyrolysis section 2 tangentially from the hopper via a feeding screw. The high-temperature gas passes through the guide vanes 16, blowing the solid pellet raw material in a swirling manner. The high-speed gas-solid fluid rotates downwards along the inner wall of the cylindrical part 21 of the pyrolysis section 2. Due to the shape of the cylinder wall, the velocity difference between the gas and solid fluids varies periodically, and there is relative motion between the gas and solids. The particles are gradually heated, and the high-temperature particles undergo pyrolysis during rotation, producing crude bio-oil into the gas phase. The gas and solid fluids gradually separate in the conical part 22 of the pyrolysis section 2. The particles continue to rotate downwards along the pipe wall until they reach the discharge port 23. The residence time of the particles in the pyrolysis section is 0.5s. The product gas is discharged through the pyrolysis section outlet (i.e., the bio-oil outlet pipe 103). The yield of crude bio-oil is 51.3%. The crude bio-oil undergoes further catalytic reforming to obtain refined bio-oil and other products.

[0071] Example 2

[0072] Room temperature nitrogen gas is initially accelerated at the first stator 13, and then accelerated to supersonic speed by the rotation of the rotor 14. This generates shock wave loss at the second stator 15, instantly raising the gas temperature to 500-550℃. The heated gas undergoes pulsating mixing in the space between the second stator 15 and the guide vanes 16, resulting in a more uniform gas temperature. Biomass pellets (pine waste) and molecular sieve catalyst are premixed and then tangentially fed into the pyrolysis section 2 via a feeding screw from the hopper. The high-temperature gas passes through the guide vanes 16, blowing the solid pellet raw material in a swirling motion. The high-speed gas-solid fluid rotates downwards along the inner wall of the cylindrical section 21 of the pyrolysis section 2. Due to the shape of the cylinder wall, the velocity difference between the gas and solid fluids within it varies periodically. In the pyrolysis section, there is relative motion between the gas and solid phases. The particles are gradually heated and undergo pyrolysis during rotation, producing crude bio-oil into the gas phase. The crude product continues to contact the molecular sieve catalyst and continues to swirl within the pyrolysis section, where it is converted into refined bio-oil through in-situ catalytic reforming. The gas and solid fluids gradually separate in the conical section 22 of the pyrolysis section 2. The particles continue to rotate downwards along the pipe wall until they reach the discharge port 23. The residence time of the particles in the pyrolysis section is 1 second. The gas is discharged through the pyrolysis section outlet (i.e., the bio-oil outlet pipe 103). The yield of low-carbon aromatic bio-oil is 22.5%. The discharged particles are subjected to flotation, and the lighter residual carbon and ash particles are discharged, while the heavier catalyst re-enters the silo and premixes with fresh raw materials.

[0073] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A shock vortex reactor for biomass flash pyrolysis, characterized in that, The reactor is a tubular structure, including: The shock wave preheating section includes a tubular shell and a rotating shaft installed inside the shell. The circumferential gap between the rotating shaft and the tubular shell forms a gas channel. Along the gas flow direction, the gas channel is sequentially equipped with: a first stator for initial acceleration of the process gas, a rotor for accelerating the process gas to supersonic speeds, and a second stator for generating shock wave losses and rapidly raising the temperature of the process gas. The biomass pellet inlet is located downstream of the shock wave preheating section and tangentially arranged along the circumference of the tubular reactor, for mixing the biomass pellets with the shock wave-heated gas. Guide vanes for forming a swirling flow are provided between the biomass pellet inlet and the shock wave preheating section. The pyrolysis section is located below the biomass pellet inlet and includes a cylindrical section and a conical section; the biomass pellets and high-temperature gas form a swirling flow in the cylindrical section, and pyrolysis is carried out in the swirling flow state, while gas-solid separation is carried out in the conical section.

2. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The first stator is fixed to the inner wall of the housing and is composed of a plurality of radially extending curved first grating blades; the rotor is fixed to the rotating shaft and is composed of a plurality of radially extending curved second grating blades, and the rotor is located at an adjacent position downstream of the first stator airflow; the second stator is fixed to the inner wall of the housing and is composed of a plurality of radially extending curved third grating blades, and the second stator is located at an adjacent position downstream of the rotor airflow.

3. The shock vortex reactor for biomass flash pyrolysis according to claim 2, characterized in that, The first and third grid blades at corresponding positions have the same bending direction, while the first and second grid blades at corresponding positions have opposite bending directions.

4. The shock vortex reactor for biomass flash pyrolysis according to claim 3, characterized in that, The gas channel constructed by the first grating blade has a tapered structure; the gas channel constructed by the second grating blade has a structure that is narrowest in the middle and gradually expands towards both ends; the gas channel constructed by the third grating blade has a gradually expanding structure.

5. The shock vortex reactor for biomass flash pyrolysis according to claim 4, characterized in that, The blade profile parameters of the first, second, and third grating blades are set according to the heating temperature requirements of the process gas.

6. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The height-to-diameter ratio of the cylindrical section of the pyrolysis segment is set according to the pyrolysis time of the biomass particles.

7. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The cone-shaped end of the pyrolysis section is a solid particle discharge port, used to discharge or recycle the residual carbon particles after the biomass pellets are pyrolyzed.

8. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The guide vane is fixed to the inner wall of the housing and is composed of multiple radially extending curved fourth grating blades.

9. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The biomass pellet inlets are two or more, and are evenly spaced along the circumference of the shell.

10. The shock vortex reactor for biomass flash pyrolysis according to claim 1, characterized in that, The reactor is equipped with a bio-oil outlet pipe. The upper part of the bio-oil outlet pipe passes through the rotating shaft of the shock wave preheating section at the center and extends from the top of the reactor. The lower part extends above the conical part of the pyrolysis section. It is used to discharge the produced gaseous crude bio-oil product and to provide an annular spiral descent space for the biomass particles during the pyrolysis process. A cylindrical metal mesh is provided below the bio-oil outlet pipe to filter out ash particles and residual carbon particles entrained in the gaseous bio-oil.

11. A shock vortex method for biomass flash pyrolysis, characterized in that, Using the reactor as described in any one of claims 1 to 10, the method includes the following steps: A. The process gas is introduced into the shock wave preheating section as a carrier gas. After the process gas is initially accelerated by the first stator, it is accelerated to supersonic speed by the rotor. B. The supersonic process gas generates shock wave losses in the second stator, and the temperature of the process gas is rapidly increased while its velocity is reduced. C. The subsonic high-temperature gas forms a swirling flow at the outlet of the second stator, and the gas in the swirling state mixes with the biomass particles that enter the reactor tangentially. D. The high-speed gas-solid mixture rotates downward along the inner wall of the cylindrical part of the pyrolysis section. The biomass particles are pyrolyzed in a swirling state, and the crude bio-oil product is discharged into the gas phase through the bio-oil outlet pipe for the next step of catalytic reforming. The gas-solid mixture is separated into gas and solid in the conical part.

12. The shock vortex method for biomass flash pyrolysis according to claim 11, characterized in that, Also includes: E. Solid residual carbon particles are discharged from the bottom outlet; Cyclic pyrolysis is carried out when the residual carbon particles are not completely pyrolyzed.

13. The shock vortex method for biomass flash pyrolysis according to claim 11, characterized in that, In step B, the temperature of the process gas is rapidly raised to 500-550°C.

14. The shock vortex method for biomass flash pyrolysis according to claim 11, characterized in that, The residence time of the biomass particles in the pyrolysis section is 0.5-1 second.

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