Novel airflow purging fluidized bed

Abstract

The utility model relates to the technical field of fluidized beds, in particular to a novel airflow purging fluidized bed, which comprises a reactor cylinder, an airflow purge device and a gas distribution plate, the airflow purge device and the gas distribution plate are arranged on the reactor cylinder, and an air outlet and an air inlet are respectively arranged at the upper end and the lower end of the reactor cylinder. The gas distribution plate is funnel-shaped and is arranged between the airflow blowing device and the gas inlet; the airflow blowing devices are obliquely arranged towards the axis of the reactor barrel, the gas outlet ends of the airflow blowing devices are close to the gas distribution plate, the multiple airflow blowing devices are evenly arranged in the circumferential direction of the reactor barrel, and a discharging opening is formed in the bottom of the reactor barrel. According to the fluidized bed reactor, the fluidized state of materials in the fluidized bed is enhanced through the interaction coordination purging effect of the airflow purging device on the fluidized bed reactor barrel and the bottom funnel-shaped gas distribution plate, gas-solid contact between solid materials and reaction gas is enhanced, the production speed is increased, and the product quality is improved; and the funnel-shaped gas distribution plate effectively prevents the materials from being accumulated at corners, so that the deposition uniformity is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to fluidized bed technical field especially relates to a novel airflow purging fluidized bed. BACKGROUND

[0002] The rapid popularization and upgrading of electric vehicles and portable electronic devices have put forward more stringent requirements on the energy density, cycle stability and fast charging capacity of lithium ion batteries. The traditional graphite negative electrode material has been difficult to meet the demand of the current market for higher energy density batteries due to its theoretical specific capacity limit of 372mAh / g. Under this background, exploring and developing new negative electrode materials with high specific capacity and excellent cycle performance has become a hot spot of industry research. Silicon-carbon composite material has become a potential material to replace traditional graphite negative electrode due to its high theoretical specific capacity of silicon-based components, combined with the stability and conductivity enhancement characteristics of porous carbon structure.

[0003] Although silicon-carbon negative electrode material has broad prospects, the technical challenges in its preparation process cannot be ignored, especially in the process of using fluidized bed equipment for chemical vapor deposition (CVD) to prepare silicon-carbon negative electrode material. The current design of airflow purging angle in the fluidized bed device is not sufficient, which limits the contact between the material and the reaction gas, reduces the deposition efficiency; the traditional gas distribution plate adopts a flat structure, which causes the material to accumulate at the corners, further aggravating the uneven deposition, and reducing the production efficiency and product qualification rate.

[0004] The information disclosed in this BACKGROUND section is only intended to enhance the understanding of the general background of the present disclosure and is not intended to be recognized as prior art to the present disclosure. SUMMARY

[0005] The purpose of the utility model is to provide a novel airflow purging fluidized bed for the defects in the prior art.

[0006] In order to achieve the above purpose, the utility model adopts the technical scheme of:

[0007] A novel airflow purging fluidized bed, comprising a reactor cylinder and a gas flow purger and a gas distribution plate arranged thereon, an air outlet and an air inlet are arranged at the upper and lower ends of the reactor cylinder respectively, the gas distribution plate is funnel-shaped and arranged between the gas flow purger and the air inlet.

[0008] The gas flow purger is inclined towards the axis of the reactor cylinder, and its air outlet end is close to the gas distribution plate, the gas flow purger is uniformly provided with a plurality of gas flow purgers in the circumferential direction of the reactor cylinder, and a discharge port is arranged at the bottom of the reactor cylinder.

[0009] Further, the reactor cylinder comprises a reaction section and an expansion section and a contraction section arranged at the upper and lower ends of the reaction section respectively, the gas outlet is arranged at the expansion section, and the gas inlet and the discharge outlet are arranged at the contraction section.

[0010] The gas flow purger is arranged at the middle and below of the reaction section, the feeding inlet is arranged at the reaction section close to the gas flow purger, and the gas distribution plate is arranged at one end of the reaction section close to the contraction section.

[0011] Further, the gas distribution plate comprises a first plate body and a second plate body, the first plate body is arranged coaxially with the reactor cylinder in a conical structure, and the second plate body is arranged in a ring shape outside the first plate body.

[0012] A central through hole is arranged at the center of the first plate body, a plurality of first through holes are arranged on the first plate body, and a plurality of second through holes are arranged on the second plate body.

[0013] Further, the first plate body, the second plate body and the gas flow purger are all arranged obliquely, and satisfy the following relationships:

[0014] 0° < α ≤ γ ≤ β < 90°;

[0015] Wherein, α represents the included angle between the first plate body and the horizontal plane, β represents the included angle between the second plate body and the horizontal plane, and γ represents the included angle between the gas flow purger and the horizontal plane.

[0016] Further, the hole diameters of the through holes arranged on the gas distribution plate gradually decrease from inside to outside.

[0017] Further, the hole diameters of the central through hole, the first through hole and the second through hole satisfy the following relationships:

[0018] A ≥ B ≥ C;

[0019] Wherein, A represents the hole diameter of the central through hole, B represents the hole diameter of the first through hole, and C represents the hole diameter of the second through hole.

[0020] Further, the number of layers of the gas flow purger arranged on the reactor cylinder is 1-5, the number of the gas flow purgers arranged on each layer is 1-16, and the hole diameter of the gas flow purger is 0.1-10 mm.

[0021] Further, the number of layers of the gas flow purger arranged on the reactor cylinder is 2, and the number of the gas flow purgers arranged on each layer is 8-14, and the hole diameter of the gas flow purger is 1-6 mm.

[0022] Further, a buffer heating tank is arranged at the gas inlet.

[0023] Further, an electric heater is arranged on the wall of the reaction section, and a heat preservation layer is arranged outside the electric heater.

[0024] The utility model discloses the beneficial effect is:

[0025] The application enhances the fluidization state of the internal material of the fluidized bed through the interactive and coordinated purging effect of the gas flow purger on the fluidized bed reactor cylinder and the bottom funnel-shaped gas distribution plate, strengthens the gas-solid contact of the solid material and the reaction gas, is favorable for accelerating the production speed and improving the product quality, and the funnel-shaped gas distribution plate effectively prevents the accumulation of the material at the corner and improves the deposition uniformity. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only some embodiments in the utility model, and for the ordinary skilled in the art, other drawings can also be obtained according to these drawings without creating labor.

[0027] Figure 1 It is the layout schematic view of the gas flow purger and the gas distribution plate in the utility model;

[0028] Figure 2 It is the structural schematic view of the new gas flow purging fluidized bed in the utility model;

[0029] Figure 3 It is the top view of the gas distribution plate in the utility model;

[0030] Figure 4 It is the layout schematic view of the gas flow purger in the utility model.

[0031] The drawings show that 1 is the reactor cylinder, 11 is the reaction section, 12 is the expansion section, 13 is the contraction section, 14 is the gas outlet, 15 is the gas inlet, 16 is the discharge port, 17 is the feeding port, 2 is the gas flow purger, 3 is the gas distribution plate, 31 is the first plate body, 311 is the center through hole, 312 is the first through hole, 32 is the second plate body, 321 is the second through hole, and 4 is the buffer heating tank. DETAILED DESCRIPTION

[0032] The technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model, and obviously, the described embodiments are only some embodiments of the utility model, not all the embodiments.

[0033] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. Where, when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can also be present. As used herein the terms "vertical", "horizontal", "left", "right" and similar terms are used for explanation only and are not intended to limit the scope of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0035] The present application is directed to the preparation process of silicon-carbon negative electrode material, when using fluidized bed equipment for chemical vapor deposition (CVD), there are problems such as uneven deposition caused by unreasonable design of gas flow sweeping angle and gas distribution plate structure, thereby reducing deposition efficiency, production efficiency and product pass rate. A new type of gas flow sweeping fluidized bed is disclosed, which can be used for but not limited to the production of silicon-carbon negative electrode material.

[0036] As shown in Figures 1 to 4 A new type of gas flow sweeping fluidized bed, including a reactor cylinder 1 and a gas flow sweeping device 2 and a gas distribution plate 3 arranged thereon, an air outlet 14 and an air inlet 15 are arranged at the upper and lower ends of the reactor cylinder 1 respectively, the gas distribution plate 3 is funnel-shaped and arranged between the gas flow sweeping device 2 and the air inlet 15; the gas flow sweeping device 2 is inclined towards the axis of the reactor cylinder 1, and its air outlet end is close to the gas distribution plate 3, the gas flow sweeping device 2 is uniformly arranged with multiple in the circumferential direction of the reactor cylinder 1, and a discharge port 16 is arranged at the bottom of the reactor cylinder 1.

[0037] The present application significantly improves the fluidization state of the powder in the reactor by adjusting the position of the gas flow sweeping device 2 and the gas distribution plate 3 and the aperture relationship on the gas distribution plate 3. The inclined arrangement and circumferential uniform distribution of the gas flow sweeping device 2, as well as the funnel-shaped design of the gas distribution plate 3, together constitute an efficient and uniform gas flow field and material distribution system. The production speed, product quality and processing capacity of the reactor are improved.

[0038] Further, the reactor cylinder 1 comprises a reaction section 11 and an enlarged section 12 and a converging section 13 arranged at the upper and lower ends of the reaction section 11 respectively, the gas outlet 14 is arranged at the enlarged section 12, the gas inlet 15 and the discharge outlet 16 are arranged at the converging section 13; the gas flow purger 2 is arranged at the middle and below of the reaction section 11, the feeding inlet 17 is arranged at the reaction section 11 close to the gas flow purger 2, and the gas distribution plate 3 is arranged at one end of the reaction section 11 close to the converging section 13.

[0039] The gas distribution plate 3 adopts a funnel-shaped design, compared with the traditional flat plate structure, has better material guiding and airflow distribution effect; effectively avoids the accumulation of materials at the bottom corners of the reactor, and improves the uniformity of material fluidization. The gas flow purger 2 is uniformly arranged at the circumference of the reactor cylinder 1, so that the material in the reactor is subjected to uniform airflow, ensuring uniform distribution and full utilization of the reaction gas in the material, and enhancing the processing capacity and stability of the reactor.

[0040] In the embodiment, as shown in Figure 1 and Figure 3 , the gas distribution plate 3 comprises a first plate body 31 and a second plate body 32, the first plate body 31 is coaxially arranged with the reactor cylinder 1 in a conical structure, and the second plate body 32 is arranged in a ring shape outside the first plate body 31; a central through hole 311 is arranged at the center of the first plate body 31, a plurality of first through holes 312 are arranged on the first plate body 31, and a plurality of second through holes 321 are arranged on the second plate body 32.

[0041] Specifically, the first plate body 31, the second plate body 32 and the gas flow purger 2 are all arranged obliquely, and satisfy the following relationship:

[0042] 0°<α≤γ≤β<90°;

[0043] Wherein, α represents the included angle between the first plate body 31 and the horizontal plane, β represents the included angle between the second plate body 32 and the horizontal plane, and γ represents the included angle between the gas flow purger 2 and the horizontal plane.

[0044] In the specific implementation process, if the included angle between the gas flow purger 2 and the horizontal plane is too large, the airflow will tend to blow downward, and form a convection with the fluidization carrier gas introduced by the gas inlet 15 at the bottom of the reactor cylinder 1; this convection will hinder the upward flow of the material, causing the material to accumulate at the lower end of the fluidized bed reactor, reducing the deposition efficiency. The present embodiment reasonably sets the inclination angle of the gas flow purger 2, effectively avoiding the convection of the airflow.

[0045] If the angle between the gas flow purger 2 and the horizontal plane is too small, the purging gas flow will be close to the horizontal angle. Due to the stratification and uniform distribution of the gas flow purger 2 on the side wall of the reactor cylinder 1, the too small angle will cause the relative position of the gas flow purger 2 to offset each other when blowing, forming a gas wall to hinder the fluidization of the material. The present embodiment ensures the synergy between the gas flow purgers 2 by accurately calculating the inclination angle, avoiding the phenomenon of mutual offset of the gas flow.

[0046] The funnel-shaped gas distribution plate 3 in the present embodiment can more effectively prevent the material from accumulating at the bottom of the reactor. When the material sinks to the second plate body 32 with a larger inclination angle during the fluidization process, it can smoothly fall to the first plate body 31. The first plate body 31 has a smaller inclination angle, and the material can be more evenly distributed when falling onto it, and the material can be uniformly blown upward through the gas inlet group on the gas distribution plate 3, thereby realizing the uniform fluidization of the material.

[0047] In the present embodiment, as shown in Figure 3 the hole diameter of the through hole provided on the gas distribution plate 3 gradually decreases from inside to outside. Specifically, the hole diameters of the center through hole 311, the first through hole 312 and the second through hole 321 satisfy the following relationship:

[0048] A≥B≥C;

[0049] wherein A represents the hole diameter of the center through hole 311, B represents the hole diameter of the first through hole 312, and C represents the hole diameter of the second through hole 321.

[0050] The center through hole 311, as the main gas inlet 15 at the bottom, undertakes the important task of blowing the material in the fluidized bed reactor cylinder 1 upward, so its hole diameter A is relatively large to ensure sufficient gas flow and form a strong vertical upward gas flow to effectively blow and fluidize the material.

[0051] The first through hole 312 is distributed on the first plate body 31 as an auxiliary gas inlet hole, and its hole diameter B is slightly smaller than the hole diameter A of the center through hole 311. Multiple first through holes 312 assist the material fluidization through gas inlet, while ensuring uniform distribution of the gas flow in the reactor. The second through hole 321 is distributed on the second plate body 32, also as an auxiliary gas inlet hole, but its hole diameter C is the smallest. The second plate body 32 mainly plays a role in receiving and guiding the material, while ensuring that the gas flow can uniformly penetrate and assist the material fluidization.

[0052] In the present embodiment, the number of layers of the gas flow purger 2 arranged on the reactor cylinder 1 is 1-5, and the number of gas flow purgers 2 uniformly arranged in each layer is 1-16. The gas hole of the gas flow purger 2 is set to 0.1-10 mm.

[0053] Preferably, the gas flow purger 2 is arranged in two layers on the reactor cylinder 1, and 8-14 gas flow purgers 2 are evenly arranged in each layer in the circumferential direction, and the gas hole of the gas flow purger 2 is 1-6 mm.

[0054] In the design of the fluidized bed reactor, the number of layers, the number of layers, and the size of the gas hole of the gas flow purger 2 are key factors affecting the fluidization effect and deposition uniformity of the material.

[0055] When the hole diameter of the gas flow purger 2 is less than 0.1 mm, the small hole diameter will seriously limit the gas flow into the reactor, resulting in a small amount of gas entering the reactor, and the purging effect on the material is limited. This not only cannot play the role of auxiliary fluidization, but also reduces the deposition uniformity and electrochemical performance of the prepared sample.

[0056] When the hole diameter of the gas flow purger 2 is greater than 10 mm, although the gas flow increases, more gas needs to be introduced into the reactor per unit time to achieve the required gas flow. This not only causes resource waste, but also increases the pressure in the reactor, thereby affecting the fluidization state of the material. At the same time, too much gas entering will dilute the concentration of the reaction gas, reduce the utilization rate of the reaction gas, and cause the amount of gas-phase deposited material to deviate from the experimental design scheme.

[0057] By optimizing the number of layers, the number of layers, and the size of the gas hole of the gas flow purger 2, the embodiment realizes the uniform distribution of gas flow in the reactor and the efficient fluidization of the material. Not only improves the deposition uniformity and electrochemical performance of the prepared sample, but also reduces resource consumption and cost investment.

[0058] In the embodiment, a buffer heating tank 4 is arranged at the gas inlet 15. An electric heater is arranged on the cylinder wall of the reaction section 11, and a heat preservation layer is arranged outside the electric heater.

[0059] The main function of the buffer heating tank 4 is to preheat the gas introduced into the reactor to prevent the cold gas from directly entering the reactor and disturbing the internal temperature field of the reactor. Through preheating treatment, the gas can enter the reactor at an appropriate temperature, thereby maintaining the stability and uniformity of the temperature in the reactor.

[0060] Further referring to the test results of the scheme in different embodiments of the application shown in Table 1.

[0061] Example 1:

[0062] A new type of gas flow purging fluidized bed, the new type of gas flow purging fluidized bed reactor drum is provided with a gas flow purging device around the reactor drum, and a funnel-shaped gas distribution plate is arranged at the bottom of the fluidized bed reactor, and the fluidization state of the powder in the reactor is improved by adjusting the position and aperture relationship of the gas flow purging device and the gas distribution plate. The funnel-shaped gas distribution plate is composed of a first plate body and a second gas distribution plate, wherein the first plate body and the horizontal plane have an angle α of 30 degrees, the second plate body and the horizontal plane have an angle β of 60 degrees, and the reactor drum gas flow purging device and the horizontal plane have an angle γ of 45 degrees. The gas hole diameter of the funnel-shaped gas distribution plate decreases from inside to outside, the center through hole diameter A of the gas distribution plate is 10mm, the first through hole diameter B on the first plate body is 5mm, and the second through hole diameter C on the second plate body is 3mm. The gas flow purging device has a gas hole diameter of 2mm and is distributed in two layers around the reactor drum, with 12 in each layer. The new type of gas flow purging fluidized bed, the fluidized bed reaction section cylinder wall is provided with an electric heater, and the outer side of the electric heater is provided with a heat preservation layer. The new type of gas flow purging fluidized bed inlet pipe is provided with a buffer heating tank, and all the gases are preheated by the heating tank before entering the fluidized bed reactor.

[0063] A silicon-carbon negative electrode material is prepared by experimental gas phase deposition, the flow rate of the fluidized carrier gas is set to 0.02m / s, the deposition amount of silane is 50%, the deposition amount of acetylene is 5%, the deposition temperature of silane is 500℃, and the deposition temperature of acetylene is 590℃. The new type of gas flow purging fluidized bed produces a silicon-carbon negative electrode material, and the comprehensive performance test results are shown in Table 1, the first coulombic efficiency is 92.3%, the first delithiation capacity is 1954mAh / g, the capacity retention rate after 200 cycles is 88.7%, and the specific surface area is 3.8m2 / g.

[0064] Example 2:

[0065] A new type of gas flow purging fluidized bed, the new type of gas flow purging fluidized bed reactor drum is provided with a gas flow purging device around the reactor drum, and a funnel-shaped gas distribution plate is arranged at the bottom of the fluidized bed reactor, and the fluidization state of the powder in the reactor is improved by adjusting the position and aperture relationship of the gas flow purging device and the gas distribution plate. The funnel-shaped gas distribution plate is composed of a first plate body and a second plate body, wherein the first plate body and the horizontal plane have an angle α of 30 degrees, the second plate body and the horizontal plane have an angle β of 60 degrees, and the reactor drum gas flow purging device and the horizontal plane have an angle γ of 60 degrees. The gas hole diameter of the funnel-shaped gas distribution plate decreases from inside to outside, the center through hole diameter A of the gas distribution plate is 10mm, the first through hole diameter B on the first plate body is 5mm, and the second through hole diameter C on the second plate body is 3mm. The gas flow purging device has a gas hole diameter of 2mm and is distributed in two layers around the reactor drum, with 12 in each layer. The new type of gas flow purging fluidized bed, the fluidized bed reaction section cylinder wall is provided with an electric heater, and the outer side of the electric heater is provided with a heat preservation layer. The new type of gas flow purging fluidized bed inlet pipe is provided with a buffer heating tank, and all the gases are preheated by the heating tank before entering the fluidized bed reactor.

[0066] The silicon-carbon negative electrode material was prepared by experimental vapor deposition. The flow rate of the fluidized carrier gas was set to 0.02 m / s, the deposition amount of silane was 50%, the deposition amount of acetylene was 5%, the deposition temperature of silane was 500°C, and the deposition temperature of acetylene was 590°C. The comprehensive performance of the new gas flow purging fluidized bed for producing the silicon-carbon negative electrode material was tested, and the test results are shown in Table 1. The first coulombic efficiency was 90.3%, the first delithiation capacity was 1921 mAh / g, the capacity retention rate after 200 cycles was 85.4%, and the specific surface area was 9.4 m2 / g. As shown in Table 1.

[0067] Example 3:

[0068] A new gas flow purging fluidized bed is provided with a gas flow purger around the reactor cylinder, and a funnel-shaped gas distribution plate is arranged at the bottom of the fluidized bed reactor. The fluidization state of the powder in the reactor is improved by adjusting the position and pore size relationship between the gas flow purger and the gas distribution plate. The funnel-shaped gas distribution plate is composed of a first plate body and a second plate body, wherein the first plate body has an angle α of 60 degrees with the horizontal plane, the second plate body has an angle β of 60 degrees with the horizontal plane, and the gas flow purger of the reactor cylinder has an angle γ of 60 degrees with the horizontal plane. The pore size of the funnel-shaped gas distribution plate decreases from inside to outside. The center through hole of the gas distribution plate has a pore size A of 10 mm. The first through hole of the first plate body has a pore size B of 5 mm. The second through hole of the second plate body has a pore size C of 3 mm. The gas flow purger has a pore size of 2 mm and is distributed in two layers around the reactor cylinder, with 12 holes in each layer. The new gas flow purging fluidized bed is provided with an electric heater on the cylinder wall of the fluidized bed reaction section, and a heat preservation layer is arranged outside the electric heater. The gas inlet pipe of the new gas flow purging fluidized bed is provided with a buffer heating tank, and all the gases are preheated by the heating tank before being introduced into the fluidized bed reactor.

[0069] The silicon-carbon negative electrode material was prepared by experimental vapor deposition. The flow rate of the fluidized carrier gas was set to 0.02 m / s, the deposition amount of silane was 50%, the deposition amount of acetylene was 5%, the deposition temperature of silane was 500°C, and the deposition temperature of acetylene was 590°C. The comprehensive performance of the new gas flow purging fluidized bed for producing the silicon-carbon negative electrode material was tested, and the test results are shown in Table 1. The first coulombic efficiency was 90.3%, the first delithiation capacity was 1921 mAh / g, the capacity retention rate after 200 cycles was 85.4%, and the specific surface area was 9.4 m2 / g. As shown in Table 1.

[0070] Comparative Example 1:

[0071] A novel air-purged fluidized bed reactor features air-purgers surrounding the reactor cylinder and a funnel-shaped gas distribution plate at the bottom. The fluidization state of the powder within the reactor is improved by adjusting the position and aperture relationship between the air-purgers and the gas distribution plate. The funnel-shaped gas distribution plate consists of a first plate and a second plate. The first plate forms a 30-degree angle α with the horizontal plane, the second plate forms a 60-degree angle β with the horizontal plane, and the air-purgers form a 20-degree angle γ with the horizontal plane. The aperture of the gas pores in the funnel-shaped gas distribution plate decreases sequentially from the inside out. The diameter A of the central through-hole in the gas distribution plate is 10 mm, the diameter B of the first through-hole on the first plate is 5 mm, and the diameter C of the second through-hole on the second plate is 3 mm. The air-purgers have 2 mm aperture pores distributed in a double layer around the reactor cylinder, with 12 pores in each layer. The novel air-purged fluidized bed also includes an electric heater on the reactor cylinder wall of the reaction section, with an insulation layer on the outside of the heater. The new type of airflow-purged fluidized bed has a buffer heating tank on the external pipeline of the air inlet. All gases are preheated in the heating tank before entering the fluidized bed reactor.

[0072] Silicon-carbon anode materials were prepared by experimental vapor deposition. The fluidized carrier gas flow rate was set to 0.02 m / s, the silane deposition amount to 50%, the acetylene deposition amount to 5%, the silane deposition temperature to 500℃, and the acetylene deposition temperature to 590℃. Comprehensive performance tests were conducted on the silicon-carbon anode materials produced by the novel air-purge fluidized bed. The test results are shown in Table 1. The initial coulombic efficiency was 81.6%, the initial delithiation capacity was 1689 mAh / g, the capacity retention rate after 200 cycles was 58.6%, and the specific surface area was 126.7 m² / g. Because the angle γ between the reactor shell air purger and the horizontal plane was smaller than the angle α between the first plate and the horizontal plane, the purge airflow entered at a near-horizontal angle. This angle canceled out the purge from the opposing airflow, and an air wall formed horizontally, hindering the fluidization of the material and affecting its fluidization state. The reaction gas introduced through the bottom air inlet will also encounter resistance when passing through these air walls, resulting in uneven gas distribution in the fluidized bed reactor, affecting the uniformity of material deposition, significantly reducing the material's initial efficiency, and affecting the gas phase deposition coating, resulting in uneven material coating and a larger specific surface area.

[0073] Comparative Example 2:

[0074] A new type of gas flow purging fluidized bed, a gas flow purging device is arranged around the reactor cylinder, a funnel-shaped gas distribution plate is arranged at the bottom of the fluidized bed reactor, and the fluidization state of the powder in the reactor is improved by adjusting the position and aperture relationship of the gas flow purging device and the gas distribution plate. The funnel-shaped gas distribution plate is composed of a first plate body and a second plate body, wherein the included angle α between the first plate body and the horizontal plane is 30 degrees, the included angle β between the second plate body and the horizontal plane is 60 degrees, and the included angle γ between the reactor cylinder gas flow purging device and the horizontal plane is 45 degrees. The hole diameter of the funnel-shaped gas distribution plate decreases from inside to outside, the hole diameter A of the center hole of the gas distribution plate is 2mm, the hole diameter B of the first hole of the first plate body is 5mm, and the hole diameter C of the second hole of the second plate body is 8mm. The gas flow purging device has a gas hole diameter of 2mm and is distributed in two layers around the reactor cylinder, with 12 in each layer. The new type of gas flow purging fluidized bed, the fluidized bed reaction section cylinder wall is provided with an electric heater, and the outer side of the electric heater is provided with a heat preservation layer. The gas inlet outer pipeline of the new type of gas flow purging fluidized bed is provided with a buffer heating tank, and all the gases are preheated by the heating tank before being introduced into the fluidized bed reactor.

[0075] The silicon-carbon negative electrode material is prepared by experimental gas deposition, the flow rate of the fluidized carrier gas is set to 0.02m / s, the deposition amount of silane is 50%, the deposition amount of acetylene is 5%, the deposition temperature of silane is 500℃, and the deposition temperature of acetylene is 590℃. The new type of gas flow purging fluidized bed produces silicon-carbon negative electrode material, and the comprehensive performance test results are shown in Table 1, the first coulombic efficiency is 84.3%, the first delithiation capacity is 1720mAh / g, the capacity retention rate after 200 cycles is 69.8%, and the specific surface area is 32.4m2 / g. Because the hole diameter of the gas distribution plate is A

[0076] Comparative Example 3:

[0077] A new type of gas flow purging fluidized bed is provided with a gas flow purger around the reactor cylinder, and a funnel-shaped gas distribution plate is arranged at the bottom of the fluidized bed reactor, and the fluidization state of the powder in the reactor is improved by adjusting the position and aperture relationship of the gas flow purger and the gas distribution plate. The funnel-shaped gas distribution plate is composed of a first plate body and a second plate body, wherein the first plate body and the horizontal plane have an angle α of 30 degrees, the second plate body and the horizontal plane have an angle β of 60 degrees, and the gas flow purger of the reactor cylinder and the horizontal plane have an angle γ of 45 degrees. The hole diameters of the funnel-shaped gas distribution plate decrease from inside to outside, the hole diameter A of the center through hole of the gas distribution plate is 10mm, the hole diameter B of the first through hole on the first plate body is 5mm, and the hole diameter C of the second through hole on the second plate body is 3mm. The hole diameter of the gas flow purger is 2mm and is double-layer distributed around the reactor cylinder, and each layer is distributed with 12 holes. The new type of gas flow purging fluidized bed is provided with an electric heater on the cylinder wall of the fluidized bed reaction section, and a heat preservation layer is arranged outside the electric heater.

[0078] The silicon-carbon negative electrode material is prepared by experimental gas phase deposition, the flow rate of the fluidized carrier gas is 0.02 m / s, the deposition amount of silane is 50%, the deposition amount of acetylene is 5%, the deposition temperature of silane is 500 DEG C, and the deposition temperature of acetylene is 590 DEG C. The new type of gas flow purging fluidized bed is used for producing the silicon-carbon negative electrode material, and the comprehensive performance test results are shown in Table 1, the first coulombic efficiency is 87.4%, the first delithiation capacity is 1780 mAh / g, the capacity retention rate after 200 cycles is 73.7%, and the specific surface area is 23.7 m2 / g. Since the process gas is not preheated by a buffer heating tank before entering the fluidized bed reactor, the fluidized bed reactor is in a high temperature state, the fluidized carrier gas and the reaction gas are normal temperature gases, the gas entering the fluidized bed reactor disturbs the temperature field in the reactor, so that the actual temperature in the reactor is lower than the set temperature, the gas phase deposition temperature is reduced, the decomposition and deposition efficiency of the reaction gas (such as silane, acetylene, propylene, etc.) is affected, and the utilization rate is reduced, so the silicon deposition amount is low, the material first efficiency and capacity are reduced, and the specific surface area is increased.

[0079] Table 1

[0080]

[0081] The present application enhances the fluidization state of the material in the fluidized bed by the interactive and coordinated purging effect of the gas flow purger on the reactor cylinder and the funnel-shaped gas distribution plate at the bottom, strengthens the gas-solid contact of the solid material and the reaction gas, is beneficial to speed up the production speed, and improves the product quality. Meanwhile, the funnel-shaped gas distribution plate effectively prevents the accumulation of the material in the corner, and improves the deposition uniformity.

[0082] The person skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments, the above-mentioned embodiments and the description are only for explaining the principle of the utility model, and various changes and improvements can be made to the utility model without departing from the spirit and scope of the utility model, and these changes and improvements all fall within the scope of the utility model claimed for protection. The scope of protection of the utility model is defined by the appended claims and their equivalents.

Claims

1. A novel gas flow purging fluidized bed characterized in that, The reactor cylinder and the gas flow purger and the gas distribution plate are provided, the gas outlet and the gas inlet are respectively arranged at the upper and lower ends of the reactor cylinder, and the gas distribution plate is funnel-shaped and arranged between the gas flow purger and the gas inlet; The gas flow purger is arranged to be inclined to the axis of the reactor cylinder, and the gas outlet end of the gas flow purger is close to the gas distribution plate, a plurality of gas flow purgers are uniformly arranged on the circumference of the reactor cylinder, and a discharge port is arranged at the bottom of the reactor cylinder.

2. The novel gas purging fluidized bed according to claim 1, characterized in that, The reactor cylinder comprises a reaction section and an enlarged section and a converging section arranged at the upper and lower ends thereof respectively, the gas outlet is arranged at the enlarged section, and the gas inlet and the discharge port are arranged at the converging section; The gas flow purger is arranged at the middle and below of the reaction section, a feeding port is arranged at the reaction section close to the gas flow purger, and the gas distribution plate is arranged at one end of the reaction section close to the converging section.

3. The novel gas purging fluidized bed according to claim 1, characterized in that, The gas distribution plate comprises a first plate body and a second plate body, the first plate body is arranged coaxially with the reactor cylinder in a conical structure, and the second plate body is arranged in a ring shape outside the first plate body; A central through hole is arranged at the center of the first plate body, a plurality of first through holes are arranged on the first plate body, and a plurality of second through holes are arranged on the second plate body.

4. The novel gas purging fluidized bed according to claim 3, characterized in that, The first plate body, the second plate body and the gas flow purger are all arranged to be inclined, and satisfy the following relationship: 0° < α ≤ γ ≤ β < 90°; Wherein, α represents the included angle between the first plate body and the horizontal plane, β represents the included angle between the second plate body and the horizontal plane, and γ represents the included angle between the gas flow purger and the horizontal plane.

5. The novel gas purged fluidized bed according to claim 3, wherein, The hole diameters of the through holes arranged on the gas distribution plate gradually decrease from inside to outside.

6. The novel gas purged fluidized bed according to claim 5, characterized in that The hole diameters of the central through hole, the first through hole and the second through hole satisfy the following relationship: A ≥ B ≥ C; Wherein, A represents the hole diameter of the central through hole, B represents the hole diameter of the first through hole, and C represents the hole diameter of the second through hole.

7. The novel gas purged fluidized bed according to claim 1, wherein, The number of layers of the gas flow purger arranged on the reactor cylinder is 1-5, the number of the gas flow purgers uniformly arranged on each layer is 1-16, and the air hole of the gas flow purger is arranged to be 0.1-10 mm.

8. The novel gas purged fluidized bed according to claim 1, wherein, The number of layers of the gas flow purger arranged on the reactor cylinder is 2, and 8-14 are uniformly arranged along the circumference of each layer, and the air hole of the gas flow purger is arranged to be 1-6 mm.

9. The novel gas purged fluidized bed according to claim 1, wherein, A buffer heating tank is arranged at the gas inlet.

10. The novel gas purged fluidized bed according to claim 2, wherein, An electric heater is arranged on the cylinder wall of the reaction section, and a heat preservation layer is arranged outside the electric heater.

Images