Adjustable fluidization gas inlet device and fluidized bed-chemical vapor deposition reactor

Abstract

The invention provides an adjustable fluidization gas inlet device and a fluidized bed-chemical vapor deposition reactor, and relates to the technical field. The device is suitable for being arranged on a fluidized bed reactor and comprises a porous sintering gasification plate, a rotational flow gas inlet system, a stirring system and a gas inlet pipeline, the porous sintering gasification plate is suitable for being installed at the bottom of the fluidized bed reactor to be connected with the gas inlet pipeline, the cyclone gas inlet system comprises a plurality of gas inlet branches arranged on the peripheral side of the lower portion of the fluidized bed reactor in the inscribed circle direction, gas flow enters the fluidization gas inlet device at a preset angle, and rotating ascending gas flow is formed; the stirring system comprises reverse propulsion type stirring blades and a stirring motor, and the stirring motor is suitable for driving the stirring blades to rotate so as to drive materials to move in the axial direction; the gas inlet pipeline is connected with the porous sintering gasification plate and the cyclone gas inlet system and is used for introducing carrier gas and / or process gas into the fluidized bed reactor. According to the scheme, the uniformity of the fluidization process can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of fluidized bed equipment, and in particular to an adjustable fluidized air inlet device and a fluidized bed-chemical vapor deposition reactor. Background Art

[0002] The new vapor-deposited silicon-carbon negative electrode material is a lithium battery negative electrode material obtained by uniformly depositing silicon nanoparticles inside the porous carbon material skeleton. Compared with traditional high-specific-capacity negative electrode materials such as silicon-oxygen and ground silicon-carbon, the use of vapor-deposited silicon-carbon significantly improves the battery's first-cycle efficiency, energy density, cycle performance, and cell expansion. The current mainstream in the industry uses a fluidized bed as a reactor to achieve the uniformity of silane adsorption and cracking inside the porous carbon as much as possible, and finally obtain nano-silicon particles.

[0003] However, current fluidized bed equipment has the following disadvantages:

[0004] 1. Porous carbon materials belong to Class C powder lightweight materials, which are prone to channeling during the fluidization process. When channeling occurs, the density distribution in the bed is uneven, and the gas cannot fully contact the particles, which deteriorates the process conditions such as medium transfer and heat transfer;

[0005] 2. At present, the industry generally adopts the single-point / multi-point air intake at the bottom of the fluidized bed to achieve the fluidization of the powder inside the fluidized reactor. The single-point / multi-point air intake is to blow high-speed air into the powder through a small pipeline to achieve fluidization. This method will cause the material flow rate to be faster near the air intake point, and the material cannot be fully fluidized at a distance from the air intake point;

[0006] 3. In order to achieve a uniform fluidization effect, the industry often adopts the method of increasing the air intake and introducing forced stirring. Since the reaction temperature of the vapor deposition silicon carbon process is relatively high (about 550-650°C), a large amount of air intake can easily cause the reactor thermal balance failure, which is not conducive to the vapor deposition process; although the introduction of the forced stirring device has reduced the gas consumption to a certain extent, the porous carbon is a light powder and is easy to break. The forced stirring device has a strong shear force, which can easily destroy the skeleton structure of the porous carbon itself and affect the product qualification rate. Summary of the invention

[0007] The invention discloses an adjustable fluidizing air inlet device, aiming to improve the above-mentioned problems.

[0008] The present invention adopts the following scheme:

[0009] An adjustable fluidized air intake device, suitable for being arranged on a fluidized bed reactor, comprises: a porous sintered gasification plate, a cyclone air intake system, a stirring system and an air intake pipeline; wherein:

[0010] The porous sintered gasification plate is suitable for being installed at the bottom of the fluidized bed reactor to connect the air inlet pipeline, thereby converting the multi-point air inlet of the air inlet pipeline into a plane air outlet to make the air inlet uniform;

[0011] The cyclone air intake system includes a plurality of air intake branches arranged along the inner circle direction on the lower circumference of the fluidized bed reactor, so that the airflow enters the fluidized air intake device at a predetermined angle and forms a rotating upward airflow, thereby driving the material to rise along the side wall of the fluidized bed, so as to achieve good heat energy transfer and medium transfer;

[0012] The stirring system comprises a reverse-propulsion stirring blade and a stirring motor, wherein the stirring motor is suitable for driving the stirring blade to rotate so as to drive the material to move axially;

[0013] The air inlet pipeline is connected to the porous sintered gasification plate and the cyclone air inlet system, and is used to introduce carrier gas and / or process gas into the fluidized bed reactor and adjust the ratio of the gas volume entering the fluidized bed reactor from the porous sintered gasification plate and from the air inlet branch.

[0014] Furthermore, a hollow space is formed between the bottom of the porous sintered gasification plate and the fluidized bed reactor, and the air intake system is provided with an air intake branch connected to the hollow space, so that the gas enters the bottom of the porous sintered gasification plate in a multi-point air intake manner, and after being evenly distributed through the porous sintered gasification plate, a stable air outlet surface is formed on the top surface of the porous sintered gasification plate.

[0015] Furthermore, the air intake directions of the plurality of air intake branches distributed circumferentially are inclined upward at an angle of 5° to 15° with the horizontal plane.

[0016] Furthermore, a conical dome is arranged above the connection between the stirring blade and the rotating shaft of the stirring motor. The conical dome structure enables the porous carbon material to form an internal cavity structure in the fluidized bed reactor, thereby preventing the powder material from bridging and thus avoiding the inability to disperse and fluidize the material at the center hole position.

[0017] Furthermore, the stirring motor is connected to the stirring blade via a magnetic fluid transmission device, and a rotary sealing structure is provided between the magnetic fluid transmission device and the stirring blade.

[0018] Furthermore, the air intake system includes a first air intake pipeline and a second air intake pipeline, the first air intake pipeline is connected to the air intake branch and the porous sintered gasification plate to introduce carrier gas and / or process gas into the fluidized bed reactor; the second air intake pipeline is suitable for being connected to the magnetohydrodynamic transmission device to perform fluidized gas protection on the rotating shaft to prevent material dust from returning to the rotating shaft arranged in the magnetohydrodynamic transmission device.

[0019] Furthermore, an electric regulating valve is provided on the air intake branch of the first air intake pipeline to control the ratio of the air intake through the porous sintered gasification plate and the air intake through the cyclone intake system, and the ratio of the air intake through the porous sintered gasification plate and the air intake through the cyclone intake system is between 55:45 and 65:35.

[0020] Furthermore, the rotary sealing structure includes a rotary sealing ring arranged on the stirring blade and a labyrinth sealing ring arranged on the magnetic fluid transmission device; the rotary sealing ring is provided with a plurality of raised sealing teeth, and the labyrinth sealing ring is provided with a sealing groove matching the sealing teeth, the sealing teeth are inserted into the sealing groove and a gap is left with the bottom of the sealing groove, and sealing is achieved through the throttling effect of the gas between the pores.

[0021] The present invention also provides a fluidized bed-chemical vapor deposition reactor, comprising a fluidized bed reactor, on which the adjustable fluidized air inlet device described in any one of the above items is arranged.

[0022] Beneficial effects:

[0023] This scheme can make the bed pressure in the fluidized reactor linearly distributed by setting up plane gasification combined with swirl air intake, with good fluidization uniformity and sufficient gas-solid interaction; for Class C powder materials such as porous carbon, channeling is not easy to occur during the fluidization process. The combined use of reverse-propulsion stirring blades reduces the wind speed requirements for fluidization, saves the amount of carrier gas and process gas, and at the same time, the reverse-propulsion stirring blades bring a larger circulation volume. The stirring direction of the reverse-propulsion stirring blades is consistent with the swirl air intake direction. The material swirls up along the wall, so that the gas-solid interaction and heat interaction inside the reactor are sufficient, and the destruction of particles is avoided; the electric regulating valve is used to adjust the gas distribution through plane air intake and side swirl air intake. According to the feedback of the bed pressure inside the fluidized reactor, the appropriate gas distribution ratio can be adjusted to maximize the use of carrier gas and process gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of an adjustable fluidizing air inlet device according to an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of a stirring blade of an adjustable fluidizing air inlet device according to an embodiment of the present invention;

[0026] Figure 3 It is a structural schematic diagram of a rotary sealing structure of an adjustable fluidized air inlet device according to an embodiment of the present invention;

[0027] Icons: dome, stirring blade 2, air intake branch 3, electric regulating valve 4, first air intake pipeline 5, second air intake pipeline 6, porous sintered gasification plate 7, rotary sealing structure 8, magnetofluid transmission device 9, stirring motor 10, fluidized bed reactor 11, hollow space 12, rotary sealing ring 13, labyrinth sealing ring 14. DETAILED DESCRIPTION

[0028] Combination Figures 1 to 3 As shown, this embodiment provides a fluidized bed-chemical vapor deposition reactor, including a fluidized bed reactor 11, on which an adjustable fluidized air intake device is provided. The adjustable fluidized air intake device is suitable for being arranged on the fluidized bed reactor 11, and comprises: a porous sintered gasification plate 7, a cyclone air intake system, a stirring system and an air intake pipeline; wherein, the porous sintered gasification plate 7 is suitable for being installed at the bottom of the fluidized bed reactor 11 to connect the air intake pipeline, thereby converting the multi-point air intake of the air intake pipeline into a plane air outlet to make the air intake uniform; the cyclone air intake system comprises a plurality of air intake branches 3 arranged on the circumference of the lower part of the fluidized bed reactor 11 along the inscribed circle direction, so that the airflow enters the fluidized air intake device at a predetermined angle and forms a rotating The rising airflow drives the material to rise along the side wall of the fluidized bed to achieve good heat energy transfer and medium transfer; the stirring system includes a reverse-propulsion stirring blade 2 and a stirring motor 10, and the stirring motor 10 is suitable for driving the stirring blade 2 to rotate to drive the material to move axially; the air inlet pipeline is connected to the porous sintering gasification plate 7 and the cyclone air inlet system, and is used to introduce the carrier gas and / or process gas into the fluidized bed reactor 11, and adjust the gas volume ratio from the porous sintering gasification plate 7 to the gas volume from the air inlet branch entering the fluidized bed reactor.

[0029] In this embodiment, the porous sintered gasification plate 7 is arranged at the bottom of the fluidized bed reactor 11, and a hollow space 12 is formed between the bottom of the porous sintered gasification plate 7 and the fluidized bed reactor 11. The air intake system is provided with an air intake branch connected to the hollow space 12, so that the gas enters the bottom of the porous sintered gasification plate 7 in a multi-point air intake manner, and after being evenly distributed through the porous sintered gasification plate 7, a stable gas outlet surface is formed on the top surface of the porous sintered gasification plate 7. The porous sintered gasification plate 7 is fixed by welding to prevent powder from invading the hollow space 12. The porous sintered gasification plate 7 is made of high temperature resistant metal powder and is formed by vacuum sintering, with a high porosity and a filtration accuracy of 5 to 20 um. The reaction gas or carrier gas enters the hollow space 12 through one or more air inlet branches. When the gas fills the hollow space 12, it evenly passes through the inside of the porous sintered gasification plate 7 through multiple air inlet points on the bottom side of the porous sintered gasification plate 7 to form a stable surface gas outlet form on the top surface of the porous sintered gasification plate 7. The gas outlet area is equivalent to the effective gasification area of ​​the porous gasification plate. This method can enable the entire plane material to form a relatively stable fluidized state under the action of a uniform rising airflow.

[0030] The air intake system includes a first air intake pipeline 5 and a second air intake pipeline 6. The first air intake pipeline 5 is connected to the air intake branch 3 and the porous sintered gasification plate 7 so as to introduce carrier gas and / or process gas into the fluidized bed reactor 11. The second air intake pipeline 6 is connected to the stirring system and is used to transport fluidizing gas to the stirring system as a protective gas to prevent material dust in the fluidized bed reactor from entering the rotating shaft of the stirring system and causing blockage.

[0031] Here, an electric regulating valve 4 is provided on the air intake branch 3 of the first air intake pipeline 5 to control the air intake ratio through the porous sintered gasification plate 7 and the air intake through the cyclone air intake system, so as to realize the reasonable distribution and timely regulation of the air volume. In a preferred embodiment, the ratio of the air intake of the porous sintered gasification plate 7 to the air intake of the cyclone air intake system is between 55:45 and 65:35, under which the air volume distribution can be reasonable and the utilization of the fluidizing gas can be maximized.

[0032] There are multiple air inlet branches 3, which are formed to be obliquely connected to the lower circumference of the fluidized bed reactor 11. The multiple air inlet branches 3 are arranged circumferentially along the inscribed circle of the fluidized bed reactor 11, and the air inlet direction is inclined upward at an angle of 5° to 15° with the horizontal plane. The multi-point airflow enters the fluidized air inlet device at a certain angle to form a rotating rising airflow, which drives the material to rise along the side wall of the fluidized bed. Since the fluidized bed reactor 11 mostly adopts wall heating, good heat energy transfer and medium transfer can be achieved. Furthermore, a high-temperature resistant filter element is provided at the cyclone air inlet to prevent the powder and particle materials from being blown back into the air inlet pipe and causing blockage.

[0033] Combination Figure 1 to Figure 2 As shown, the porous sintering gasification plate 7 is provided with a rotary stirring device, which includes a dome 1, stirring blades 2, a rotary sealing structure 8, a magnetic fluid transmission device 9 and a stirring motor 10; wherein, the stirring motor 10 is arranged at the bottom of the fluidized bed reactor 11, the stirring blades 2 are arranged inside the fluidized bed reactor 11 and connected to the rotating shaft, the magnetic fluid transmission device 9 is connected to the porous sintering gasification plate 7 and connects the stirring blades 2 and the stirring motor 10 to achieve sealed transmission, and the rotating shaft is arranged on the magnetic fluid transmission device 9. The stirring blades 2 adopt a reverse propulsion structure. During the fluidization air intake process, the rotary stirring device starts to run, and the running direction of the stirring blades 2 is consistent with the cyclonic air intake on the side in the horizontal direction. The ascending rotary blades drive the material to move axially, and the mechanical force replaces part of the gas suspension force, so as to achieve the effect of reducing the fluidization gas consumption. The stirring blade 2 adopts a reverse propulsion structure design, optimizes the blade design, and reduces the contact cross-sectional area of ​​the edge size. The stirring blade 2 of this structural design does not have severe turbulence during stirring, but has a large circulation volume, mainly plays a role in volume circulation, has a small shear force, and mainly plays an up and down tumbling effect, which can form an effective gas-solid interaction, while protecting the particles from being destroyed by shear force. The transmission device uses magnetic fluid for transmission, which physically isolates the inside and outside of the fluidized reactor, avoiding the leakage of dangerous process gases or the entry of air into the reactor to cause an explosion. The second air inlet pipeline is connected to the side of the magnetic fluid transmission device 9, and nitrogen is used alone as the fluidizing gas to inlet from the side of the magnetic fluid transmission device 9 to inflate the rotating shaft for protection, preventing dust from returning to the rotating shaft of the magnetic fluid, causing blockage or jamming.

[0034] A conical dome 1 is provided above the connection between the stirring blade 2 and the rotating shaft of the stirring motor 10. The conical dome 1 structure enables the porous carbon material to form an internal cavity structure in the fluidized bed reactor 11, thereby preventing the powder material from bridging and thus avoiding the inability to disperse and fluidize the material at the center hole.

[0035] Combination Figure 1 and Figure 3As shown, in the preferred embodiment, since the external area is full of powder particles and has a certain pressure during operation, the space pressure is about 100KPa. In this case, the pressurized dust will invade the shaft end through the gap under the action of the airflow pressure difference. For this reason, a rotary sealing structure 8 is used between the stirring blade 2 and the magnetic fluid transmission device 9, and a rotary seal + labyrinth seal is used. The comb-shaped structure design can achieve sealing through the throttling effect of the gas to prevent dust from intruding. Specifically, a rotary sealing ring 13 is provided on the stirring blade 2, and a labyrinth sealing ring 14 is provided on the magnetic fluid transmission device 9. The rotary sealing ring 13 is provided with a plurality of raised comb-shaped sealing teeth, and the top surface of the sealing teeth is flat; the labyrinth sealing ring 14 is provided with a sealing groove matching the sealing teeth, and the sealing teeth are inserted into the sealing groove and a gap is left between the sealing groove, and the sealing is achieved through the throttling effect of the gas between the pores. The sealing surface of the special rotary sealing structure 8 does not contact, has no dynamic friction, and will not affect the porous carbon material. The working principle of the labyrinth seal is: since many annular sealing teeth are arranged in sequence around the rotating shaft, when the gas passes through each sealing tooth, the airflow enters the annular cavity at high speed through the gap, and suddenly expands to produce a strong vortex, so that most of the energy of the airflow is converted into heat and dissipated, and the enthalpy value is restored to a value close to that before the gap. At this time, the gas pressure decreases step by step, thereby achieving a sealing effect. In conjunction with the second air inlet pipeline set at the rotating shaft to introduce protective gas for sealing protection, it can further prevent powder intrusion, achieve the sealing purpose, and effectively improve the sealing effect at the mixing system.

[0036] Through this solution, the uniformity of the fluidized reaction can be improved.

[0037] It should be understood that the above are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention.

[0038] The above description of the drawings used in the implementation manner only illustrates certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

Claims

1. An adjustable fluidized gas inlet device, suitable for being arranged on a fluidized bed reactor, characterized in that: include: Porous sintered gasification plate, swirl air intake system, stirring system and air intake pipeline; among them, The porous sintered gasification plate is suitable for being installed at the bottom of the fluidized bed reactor to connect the air inlet pipeline, thereby converting the multi-point air inlet of the air inlet pipeline into a plane air outlet to make the air inlet uniform; The cyclone air intake system includes a plurality of air intake branches arranged along the inner circle direction on the lower circumference of the fluidized bed reactor, so that the airflow enters the fluidized air intake device at a predetermined angle and forms a rotating rising airflow, thereby driving the material to rise along the side wall of the fluidized bed to achieve good heat energy transfer and medium transfer; the stirring system includes a reverse propulsion stirring blade and a stirring motor, and the stirring motor is suitable for driving the stirring blade to rotate to drive the material to move along the axial direction; The air inlet pipeline connects the porous sintered gasification plate and the cyclone air inlet system to introduce carrier gas and / or process gas into the fluidized bed reactor and adjust the ratio of gas volume entering the fluidized bed reactor from the porous sintered gasification plate and from the air inlet branch.

2. The adjustable fluidizing air inlet device according to claim 1, characterized in that: A hollow space is formed between the bottom of the porous sintered gasification plate and the fluidized bed reactor, and the air intake system is provided with an air intake branch connected to the hollow space, so that the gas enters the bottom of the porous sintered gasification plate in a multi-point air intake manner, and after being evenly distributed through the porous sintered gasification plate, a stable air outlet surface is formed on the top surface of the porous sintered gasification plate.

3. The adjustable fluidizing air inlet device according to claim 1, characterized in that: The air intake directions of the plurality of air intake branches distributed circumferentially form an upward angle of 5° to 15° with the horizontal plane.

4. The adjustable fluidizing air inlet device according to claim 1, characterized in that: A conical dome is arranged above the connection between the stirring blade and the rotating shaft of the stirring motor. The conical dome structure enables the porous carbon material to form an internal cavity structure in the fluidized bed reactor, thereby preventing the powder material from bridging and thus avoiding the inability to disperse and fluidize the material at the center hole.

5. The adjustable fluidizing air inlet device according to claim 4, characterized in that: The stirring motor is connected to the stirring blade via a magnetic fluid transmission device, and a rotary sealing structure is arranged between the magnetic fluid transmission device and the stirring blade.

6. The adjustable fluidizing air inlet device according to claim 5, characterized in that: The air intake system includes a first air intake pipeline and a second air intake pipeline. The first air intake pipeline is connected to the air intake branch and the porous sintered gasification plate to introduce carrier gas and / or process gas into the fluidized bed reactor; the second air intake pipeline is suitable for being connected to the magnetohydrodynamic transmission device to perform fluidized gas protection on the rotating shaft to prevent material dust from returning to the rotating shaft arranged in the magnetohydrodynamic transmission device.

7. The adjustable fluidizing air inlet device according to claim 6, characterized in that: An electric regulating valve is provided on the air intake branch of the first air intake pipeline to control the air intake ratio through the porous sintered gasification plate and the air intake through the cyclone air intake system, and the ratio of the air intake through the porous sintered gasification plate and the air intake through the cyclone air intake system is between 55:45 and 65:

35.

8. The adjustable fluidizing air inlet device according to claim 6, characterized in that: The rotary sealing structure includes a rotary sealing ring arranged on the stirring blade and a labyrinth sealing ring arranged on the magnetic fluid transmission device; the rotary sealing ring is provided with a plurality of raised sealing teeth, and the labyrinth sealing ring is provided with a sealing groove matching the sealing teeth, the sealing teeth are inserted into the sealing groove and a gap is left with the bottom of the sealing groove, and sealing is achieved through the throttling effect of the gas between the pores.

9. A fluidized bed chemical vapor deposition reactor, characterized in that: It comprises a fluidized bed reactor, on which is arranged an adjustable fluidizing air inlet device as described in any one of claims 1 to 8.

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