Fluidized bed calcining device
By designing a fluidized bed calcining device with a vertical structure, using inert gas to form a bulk fluidized state, and using multi-layer heating elements and cooling pipes, the problems of uneven heating, low yield and high cost of existing calcining equipment are solved, and the effects of uniform heating, increased production capacity and reduced cost are achieved.
Patent Information
- Application Number
- CN202421637589.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-07-11
AI Technical Summary
The existing calcining equipment has problems such as uneven heating, low yield and high cost, as well as metal ion pollution and high maintenance costs.
A vertical structure fluidized bed calcining device is designed, using inert gas to form a bulk fluidized state, using multi-layer heating elements to achieve uniform heating, and cooling through cooling pipes, reducing the demand for independent cooling equipment.
It achieves uniform heating, improved production capacity, no metal ion pollution and low maintenance costs, reduces production costs, and saves part of the heating energy.
Smart Images
Figure CN222799603U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a fluidized bed calcining device, in particular to a lithium iron phosphate calcining device, belonging to the technical field of calcining equipment. Background Art
[0002] Lithium iron phosphate (LiFePO4) is a positive electrode material for lithium-ion batteries. Calcination is one of the key steps in its production process. It is used to promote the chemical reaction and crystallization of the raw materials so that the raw materials form a stable lithium iron phosphate structure. Calcination equipment is a key equipment for lithium iron phosphate production. The calcination equipment in the prior art is roller kiln and rotary kiln. These two types of furnaces have a high degree of automation and controllable temperature and atmosphere, so they are widely used. However, these two types of calcination equipment in the prior art also have the following disadvantages: (1) The sintering quality of the materials in the roller kiln box is uneven; (2) There is a risk of metal ion contamination of the materials in the rotary kiln; (3) Both types of furnace equipment have the disadvantages of complex structure, high maintenance cost, and low output per unit, and cannot support larger-scale lithium iron phosphate production, thus restricting the development of the lithium iron phosphate industry. In addition, after these calcination equipment calcine the raw materials, they also need to use additional cooling equipment to cool the calcined materials, which further increases the production cost.
[0003] Therefore, there is a huge market demand prospect for designing a single set of calcination equipment with large production capacity, uniform heating, no metal ion pollution and low maintenance cost. Utility Model Content
[0004] The utility model aims to provide a fluidized bed calcining device with uniform heating and improved production capacity, so as to solve the technical problems of uneven heating, low production and high cost of calcining equipment in the prior art.
[0005] The utility model adopts the following technical scheme: a fluidized bed calcining device, which comprises a shell with a vertical structure, a feed port and an exhaust port are arranged at the top of the shell, a discharge port and an air inlet are arranged at the bottom of the shell, a vertically extending stirring shaft is arranged in the shell, the upper end of the stirring shaft passes through the top of the shell, a stirring mechanism for driving the stirring shaft to rotate is arranged outside the shell, the upper section in the shell is a calcining chamber, the lower section in the shell is a cooling chamber, the calcining chamber and the cooling chamber are connected up and down, and a material sealing section is formed at the intersection of the calcining chamber and the cooling chamber, stirring blades are distributed on a section of the stirring shaft located in the calcining chamber, heating elements spaced apart in the longitudinal direction are fixed in the calcining chamber, and cooling pipes spaced apart in the longitudinal direction are fixed in the cooling chamber; a distribution orifice plate is arranged at the bottom of the cooling chamber, air inlet holes are opened on the distribution orifice plate, the upper end of the discharge port is connected to the distribution orifice plate, the lower end of the discharge port passes through the bottom of the shell, and the air inlet is connected to a position on the shell below the distribution orifice plate.
[0006] The shell is made of metal, the inner wall of the shell is provided with a ceramic layer, the surfaces of the stirring blades and the stirring shaft are both provided with a ceramic layer, and the heating element is made of silicon carbide.
[0007] The shell comprises an upper shell and a lower shell which are fixedly connected together, the calcining chamber is located in the upper shell, and the cooling chamber is located in the lower shell.
[0008] There are two cooling pipes on the same horizontal plane in the cooling cavity, and each cooling pipe is a serpentine cooling water coil.
[0009] The heating elements on the same horizontal plane in the calcining chamber include two electric heating tubes, and each electric heating tube is bent.
[0010] A support seat is provided at the bottom of the shell body, and the lower end of the discharge port passing through the bottom of the shell body adopts an elbow structure.
[0011] The stirring shaft passes through the bottom of the shell and comes out from the elbow of the discharge port. A sealing structure is provided between the stirring shaft and the discharge port, and a bottom support bearing is provided between the stirring shaft and the support seat.
[0012] The distribution orifice plate adopts a tapered structure that gradually becomes smaller downward, and the total area of the air inlet holes accounts for 3-6% of the total area of the distribution orifice plate; the air inlet is connected obliquely upward to the bottom of the shell, and a drain port is provided on the bottom surface of the shell.
[0013] The feed port and the exhaust port are respectively located on both sides of the stirring shaft, and the lower end of the feed port is obliquely inserted into the shell and faces the stirring shaft.
[0014] There are three groups of stirring blades, and each group of stirring blades includes two stirring blades on the same plane with an angle of 180 degrees.
[0015] The beneficial effects of the utility model are as follows: the utility model is a fluidized bed working in a dispersed bed state, the shell adopts a vertical structure, the inert gas enters the bottom of the shell from the air inlet at the bottom of the shell, then enters the cooling chamber through the distribution orifice plate, and then enters the calcination chamber upward; the material in a solid powder state enters the shell from the feed inlet at the upper part of the shell, the powdered material forms a dispersed fluidized state under the action of the inert gas, the heating element in the shell uniformly calcines the material to ensure the uniformity of the material in mixing and heating; the inert gas is used as a fluidized medium to achieve mixing of the material, and the gaseous medium generated by the calcination is taken out of the calcination device; a large-volume shell can be used to ensure that the material has sufficient residence time to ensure the calcination quality, and the stirring shaft inside the shell maintains low-speed stirring during calcination to prevent large pieces of material from agglomerating. The utility model forms a weakly fluidized bulk bed in the shell. Since the airflow generally moves upward along the axial direction of the equipment, the axial movement of the material in the equipment is in a limited range, so the material forms a material sealing section of a certain height between the heating chamber and the cooling chamber; after the material is calcined in the calcining chamber, it enters the cooling chamber at the bottom of the shell through the material sealing section, and the calcined material is cooled by the medium in the cooling pipe. Since the inert gas enters the cooling chamber and is heated by the material, and then enters the calcining chamber upward to contact and fluidize with the upper calcined material, a part of the heating energy can be saved, which is a relatively energy-saving arrangement.
[0016] Since the material is in a dispersed fluidized state when calcined in the shell, it has the characteristics of uniform heating compared to fixed bed, bubbling bed, throttling bed and turbulent bed. The multi-layer heating elements distributed at intervals in the longitudinal direction can accurately control the heating temperature, ensuring the full mixing and uniform heating of the material. The shell can be designed to be large in volume, thereby increasing the production capacity. Moreover, the shell is a stationary component, and the stirring shaft rotates at a low speed, so the equipment structure is simple and reliable, and the maintenance cost is low. Compared with the prior art, no independent cooling equipment is required, which further reduces the production cost.
[0017] Preferably, the surface of the heating element is made of silicon carbide and the inner wall of the shell is sprayed with ceramic to prevent metal ion pollution.
[0018] Preferably, the distribution orifice plate with a conical structure is arranged at the bottom of the shell, and when the material passes through the shell, it generally passes through in a piston flow, so as to ensure that the overall residence time of the powder is uniform and the calcination time is basically consistent.
[0019] Preferably, the cooling pipes are all serpentine cooling water coils, which have a large contact area with the material and can quickly cool the calcined material.
[0020] Preferably, the heating element is a bent heating tube, which has a large contact area with the material and can achieve rapid and uniform heating. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1It is a structural schematic diagram of a fluidized bed calcining device according to an embodiment of the utility model;
[0022] Figure 2 yes Figure 1 AA section view;
[0023] Figure 3 yes Figure 1 BB cross-sectional view.
[0024] In the figure: 1-motor, 2-reducer, 3-coupling, 4-upper bracket, 5-upper bearing, 6-bearing seat, 7-feed port, 8-upper shaft seal, 9-exhaust port, 10-upper cover, 11-support, 12-agitation shaft, 13-heating element, 14-lower shell, 15-cooling pipe, 16-distribution orifice plate, 17-air inlet, 18-discharge port, 19-bottom support bearing, 20-sealing structure, 21-support seat, 22-exhaust port, 23-upper shell, 24-agitation blade. DETAILED DESCRIPTION
[0025] The utility model is described in detail below with reference to the accompanying drawings and specific embodiments.
[0026] like Figures 1 to 3 As shown, the fluidized bed calcining device of this embodiment includes a shell with a vertical structure, a feed port 7 and an exhaust port 9 are provided at the top of the shell, a discharge port 18 and an air inlet 17 are provided at the bottom of the shell, a vertically extending stirring shaft 12 is provided in the shell, the upper end of the stirring shaft 12 passes through the top of the shell, a stirring mechanism for driving the stirring shaft 12 to rotate is provided outside the shell, the stirring mechanism includes a motor 1, a reducer 2 and a coupling 3, the coupling 3 is connected between the stirring shaft 12 and the reducer 2, an upper bracket 4 is connected between the reducer 2 and the top of the shell, a bearing seat 6 and an upper bearing 5 are provided between the stirring shaft 12 and the upper bracket 4, and an upper shaft seal 8 is provided between the stirring shaft 12 and the top of the shell.
[0027] The upper section in the shell is a calcining chamber, and the lower section in the shell is a cooling chamber. The calcining chamber and the cooling chamber are connected up and down, and a material sealing section is formed at the intersection of the calcining chamber and the cooling chamber. A stirring blade 24 is distributed on a section of the stirring shaft 12 located in the calcining chamber. The stirring blade 24 has three groups, and each group of stirring blades 24 includes two stirring blades. The calcining chamber is fixed with a heating element 13 that is spaced apart in the longitudinal direction. The heating element 13 on the same horizontal plane in the calcining chamber includes two electric heating tubes, and each electric heating tube is bent. The cooling chamber is fixed with a cooling tube 15 that is spaced apart in the longitudinal direction. There are two cooling tubes 15 on the same horizontal plane in the cooling chamber, and each cooling tube 15 is a serpentine cooling water coil. The shell is made of metal, and there is a ceramic layer on the inner wall of the shell. The stirring blade 24 and the stirring shaft 12 surface have a ceramic layer, and the heating element 13 is made of silicon carbide. The shell comprises an upper shell 23 and a lower shell 14 which are fixedly connected together, the calcining chamber is located in the upper shell 23, and the cooling chamber is located in the lower shell 14. An upper cover 10 is fixedly connected to the top of the upper shell 14, and supports 11 are evenly distributed on the circumference of the upper part of the upper shell 23.
[0028] A distribution orifice plate 16 is provided at the bottom of the cooling chamber, and an air inlet hole is provided on the distribution orifice plate 16. The upper end of the discharge port 18 is connected to the distribution orifice plate 16, and the lower end of the discharge port 18 passes through the bottom of the shell. The air inlet 17 is connected to the position below the distribution orifice plate 16 on the shell, and the air inlet 17 is connected to the bottom of the shell obliquely upward. The distribution orifice plate 16 adopts a tapered structure that gradually becomes smaller downward, and the total area of the air inlet hole accounts for 3-6% of the total area of the distribution orifice plate; a drain port 22 is provided on the bottom surface of the shell obliquely downward.
[0029] A support seat 21 is provided at the bottom of the shell, and the lower end of the discharge port 18 passing through the bottom of the shell adopts an elbow structure. The stirring shaft 12 passes through the bottom of the shell and passes through the elbow of the discharge port 18. A sealing structure is provided between the stirring shaft 12 and the discharge port 18, and a bottom support bearing 19 is provided between the stirring shaft 12 and the support seat 21. The feed port 7 and the exhaust port 9 are respectively located on both sides of the stirring shaft 12, and the lower end of the feed port 7 is obliquely inserted into the shell and faces the stirring shaft 12.
[0030] The fluidized bed calcining device of the utility model is a fluidized bed working in a dispersed bed state, wherein the material enters from the top, and the fluidizing gas enters from the bottom plate, and a dispersed bed is formed inside the shell. When in use, the inert gas is used as the fluidizing gas, and enters from the bottom air inlet 17, first enters between the bottom of the shell and the distribution orifice plate, then enters the lower shell through the air inlet on the distribution orifice plate, and then enters the upper shell upward; the material enters the shell from the upper feed port 7 to form a fluidized bed under the action of the gas, and the heating element 13 in the upper shell 23 heats and calcines the material, and the volume of the upper shell should be able to ensure that the material has enough residence time to ensure the calcination quality; the calcined material enters the lower shell 14, and the cooling water coil in the lower shell 14 and the inert gas entering jointly cool the calcined material, and the cooled material is discharged from the discharge port 18. The gaseous substances produced by the calcination reaction are carried out of the equipment by the fluidizing gas and finally discharged from the exhaust port 9; the stirring shaft 12 is provided with several layers of stirring blades 24, which rotate at a speed of 3-10rpm. The stirring blades can achieve uniform radial distribution of the materials, break up the agglomerated blocks that may be produced during the calcination process, and also have the function of stirring and mixing the materials; the stirring shaft 12 is supported on the upper bracket 4 and the support seat 21 through the upper bearing 5 and the bottom support bearing 19 respectively, and the upper shaft seal 8 and the bottom sealing structure 20 are provided at the upper and lower parts to seal the materials. A distribution orifice plate 16 with a conical structure is provided at the bottom of the shell, and the materials generally pass through the shell in the piston flow inside the equipment to ensure that the calcination time is basically consistent; inert gas is used to make the powder material in a dispersed fluidized state, to ensure that the materials are evenly mixed in the calcination chamber and the cooling chamber, and fully and evenly exchange heat with the heating element and the heat exchange tube, to enhance heat transfer, and to ensure the uniformity of heating and cooling; a stirring shaft 12 is provided inside the shell to stir the materials at a low speed to prevent the agglomeration of large pieces of materials. The inner wall of the shell, the stirring shaft and the stirring blades can be sprayed with ceramics to prevent metal ion pollution. An air lock valve is provided at the bottom of the discharge port 18 to control the material discharge flow rate by frequency conversion, thereby controlling the overall calcination time of the material.
[0031] In the utility model, the inert gas entering from the bottom of the shell is heated by the material in the cooling chamber, and then contacts and fluidizes with the upper calcined material, which saves part of the energy of the heating gas, and is a more energy-saving equipment layout; the upper section of the shell is provided with a heating element to heat and calcine the material; the cooling medium in the cooling pipe of the lower section of the shell cools the calcined material together with the fluidizing gas. The dispersed bed is a weak fluidized state. Since the airflow generally moves upward along the axial direction of the equipment, the axial movement of the material in the equipment is in a limited range, so a gap with a height of 0.8~1.5D (D is the shell diameter) is formed between the heating chamber and the cooling chamber to achieve material sealing. The material seal between the heating chamber and the cooling chamber can achieve the isolation of the temperature difference, and the material seal distance can be controlled automatically, generally to 200mm.
[0032] During the use of the fluidized bed calcining device of the utility model, the ratio of the fluidizing gas flow rate to the material amount can control the expansion ratio of the entire material. The ratio of the fluidizing gas volume to the material mass is generally controlled at 0.2 to 1.5 m 3 / kg.
[0033] The utility model has the following advantages: (1) the material is heated under the condition of dispersed fluidized state, and the multi-layer heating element can accurately control the heating temperature, ensuring that the material is fully mixed and heated evenly; (2) the material realizes overall piston flow in the large-sized shell to ensure the overall calcination time; (3) the fluidized gas can be selected according to the process requirements to ensure the calcination atmosphere; (4) the working filling rate of the dispersed fluidized bed calcining furnace can reach 80%, compared with 20% of the rotary kiln, under the same conditions, the equipment volume is reduced by 4 times, which greatly reduces the equipment volume, thereby greatly reducing the equipment investment and the occupied area; (5) compared with the rotary kiln, the shell body is a stationary part, the stirring shaft is installed vertically and rotates at a low speed, and the surface in contact with the material is sprayed with a ceramic layer, which is not easy to fall off, avoiding metal impurities from contaminating the material; (6) the equipment structure is simple and reliable, and the maintenance cost is low; (7) the utility model can be used for the calcination of catalysts, ternary lithium battery positive electrode materials, sodium ion positive electrode materials and other similar media.
[0034] Compared with the conventional rotary kiln in the prior art, the fluidized bed calcining device of the utility model has the following advantages:
[0035] (1) The residence time of the material in the fluidized bed calcining device of the utility model is 0.5 to 4 hours, which is relatively short and controllable; while the residence time of the material in the rotary kiln is generally more than 4 hours, which is long and uncontrollable.
[0036] (2) The material filling rate in the fluidized bed calcining device of the present invention is about 80%, which is high; while the material filling rate in the rotary kiln is 15-20%, which is much smaller than the fluidized bed of the present invention.
[0037] (3) In the fluidized bed calcining device of the present invention, the flow of materials is completely dependent on gravity, and they move vertically downward without the help of external force. The materials move in a piston-like manner under the push of the fluidizing gas. In contrast, the rotary kiln uses a motor to rotate and push the materials, and the materials flow horizontally.
[0038] (4) The fluidized bed calcining device of the utility model adopts a vertical structure, which occupies a smaller area than the horizontal rotary kiln.
[0039] (5) The fluidized bed calcining device of the present invention adopts a direct heating method, which has a higher heating efficiency than the indirect heating method of the rotary kiln. Compared with the rotary kiln, the fluidized bed calcining device of the present invention can save more than 30% energy.
[0040] (6) The fluidized bed calcining device of the utility model adopts a heating and cooling integrated structure. During the direct cooling process, the intake air is heated at the same time. The intake air preheating temperature can reach above 150°C, which can maximize the recovery of heat in the heating section, improve the overall heat exchange efficiency, and achieve significant energy-saving effects. In addition, the intake air cools the material. After cooling in the cooling section, the temperature at the discharge end can be reduced to below 60°C, reducing the temperature resistance requirements of the sealing material and providing more choices for the sealing material. The rotary kiln, on the other hand, requires independent cooling equipment to heat the calcined material and cannot achieve the above effects.
[0041] (7) The diameter of the fluidized bed calcining device of the utility model ranges from 500 to 3000 mm, and the height-to-diameter ratio is 4:1 to 10:1, which can be determined according to the calcining process time of different materials. Compared with the rotary kiln, the overall footprint of the equipment is small.
[0042] The above embodiment is a preferred embodiment of the utility model, and the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model.
Claims
1. A fluidized bed calcining device, characterized in that: It includes a shell with a vertical structure, a feed port and an exhaust port are provided on the top of the shell, a discharge port and an air inlet are provided on the bottom of the shell, a vertically extending stirring shaft is provided in the shell, the upper end of the stirring shaft passes through the top of the shell, a stirring mechanism for driving the stirring shaft to rotate is provided outside the shell, the upper section in the shell is a calcining chamber, the lower section in the shell is a cooling chamber, the calcining chamber and the cooling chamber are connected up and down, and a material sealing section is formed at the intersection of the calcining chamber and the cooling chamber, stirring blades are distributed on a section of the stirring shaft located in the calcining chamber, heating elements spaced apart in the longitudinal direction are fixed in the calcining chamber, and cooling pipes spaced apart in the longitudinal direction are fixed in the cooling chamber; a distribution orifice plate is provided at the bottom of the cooling chamber, and air inlets are opened on the distribution orifice plate, the upper end of the discharge port is connected to the distribution orifice plate, the lower end of the discharge port passes through the bottom of the shell, and the air inlet is connected to a position on the shell below the distribution orifice plate.
2. The fluidized bed calcining device according to claim 1, characterized in that: The shell is made of metal, the inner wall of the shell is provided with a ceramic layer, the surfaces of the stirring blades and the stirring shaft are both provided with a ceramic layer, and the surface of the heating element is made of silicon carbide.
3. The fluidized bed calcining device according to claim 1, characterized in that: The shell comprises an upper shell and a lower shell which are fixedly connected together, the calcining chamber is located in the upper shell, and the cooling chamber is located in the lower shell.
4. The fluidized bed calcining device according to claim 1, characterized in that: There are two cooling pipes on the same horizontal plane in the cooling cavity, and each cooling pipe is a serpentine cooling water coil.
5. The fluidized bed calcining device according to claim 1, characterized in that: The heating elements on the same horizontal plane in the calcining chamber include two electric heating tubes, and each electric heating tube is bent.
6. The fluidized bed calcining device according to claim 1, characterized in that: A support seat is provided at the bottom of the shell body, and the lower end of the discharge port passing through the bottom of the shell body adopts an elbow structure.
7. The fluidized bed calcining device according to claim 6, characterized in that: The stirring shaft passes through the bottom of the shell and comes out from the elbow of the discharge port. A sealing structure is provided between the stirring shaft and the discharge port, and a bottom support bearing is provided between the stirring shaft and the support seat.
8. The fluidized bed calcining device according to claim 1, characterized in that: The distribution orifice plate adopts a tapered structure that gradually becomes smaller downward, and the total area of the air inlet holes accounts for 3-6% of the total area of the distribution orifice plate; the air inlet is connected obliquely upward to the bottom of the shell; and a drain port is provided on the bottom surface of the shell.
9. The fluidized bed calcining device according to claim 1, characterized in that: The feed port and the exhaust port are respectively located on both sides of the stirring shaft, and the lower end of the feed port is obliquely inserted into the shell and faces the stirring shaft.
10. The fluidized bed calcining device according to claim 1, characterized in that: There are three groups of stirring blades, and each group of stirring blades includes two stirring blades on the same plane with an angle of 180 degrees.