A roller kiln system

Abstract

The present invention discloses a roller kiln system, comprising a furnace body with a furnace, a sagger for containing materials, and a conveying device installed in the furnace for conveying the sagger, the furnace having a heating section, a heat preservation section, a front cooling section, and a rear enhanced cooling section connected in sequence along the conveying direction of the conveying device, a heating component is arranged in the heating section and the heat preservation section, and the roller kiln system further comprises a cooling air intake component for introducing cooling gas into the rear enhanced cooling section. The present invention has the advantages of low cost, easy manufacture, high production efficiency, etc.

Description

Technical Field

[0001] The invention relates to the technical field of kiln equipment, and in particular to a roller kiln system. Background Art

[0002] The sintering of materials such as lithium battery positive electrode materials is to place the materials in a sagger and send them into a roller kiln to complete the sintering process. The entire sintering process is roughly divided into three stages: "heating-constant temperature-cooling". The saggers for holding materials are generally made of mullite.

[0003] Currently, the above method has the following problems:

[0004] (1) Low cooling rate is a bottleneck problem that affects the sintering capacity of positive electrode materials. Positive electrode materials require that the material discharge temperature must be lower than a specific value so that the material temperature is within the normal operating temperature range of the next process equipment. For high-nickel materials, low discharge temperature can also hinder water absorption and prevent material deterioration. However, since lithium battery positive electrode materials are highly corrosive and have strict requirements for magnetic foreign matter (below 100ppb), not only is it difficult to use liquid cooling methods with better cooling effects, but it is also prohibited to directly use metals with higher thermal conductivity as heat exchange devices in the furnace. Therefore, the sintering roller kilns in the lithium battery material industry mostly use air cooling, which has a poor cooling effect (especially for materials below 300°C). Therefore, in order to meet the rigid requirements of the discharge temperature, the conveying speed can only be reduced and the residence time of the material in the cooling section can be increased, sacrificing production capacity in exchange for a lower discharge temperature.

[0005] (2) When the mullite sagger is used for more than 30 times, it will be corroded by the positive electrode material, and cracks, peeling, or even broken will appear, which seriously affects the safety of the material and even has a major risk of causing the arch kiln. Therefore, the mullite sagger needs to be replaced with a new one after it has been used for more than a certain number of times. Since the waste sagger is stained with heavy metal elements such as nickel and cobalt, it is difficult and costly to handle, which adds an extra burden to the enterprise. This is a headache for positive electrode material manufacturers.

[0006] In summary, how to improve the cooling efficiency and increase the service life of the sagger is a problem to be solved in the art. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a roller kiln system with low cost, easy manufacture and high production efficiency.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A roller kiln system comprises a furnace body with a furnace chamber, a sagger for containing materials and a conveying device installed in the furnace chamber for conveying the sagger, the furnace chamber comprising a heating section, a heat preservation section, a front cooling section and a rear enhanced cooling section which are sequentially connected along a conveying direction of the conveying device, a heating component is arranged in the heating section and the heat preservation section, and the roller kiln system is further provided with a cooling air intake component for introducing cooling gas into the rear enhanced cooling section.

[0010] As a further improvement of the above technical solution:

[0011] The cooling air intake assembly includes multiple upper cooling air outlet pipes, multiple lower cooling air outlet pipes and a cold air supply mechanism for supplying cooling gas to each upper cooling air outlet pipe and each lower cooling air outlet pipe. The multiple upper cooling air outlet pipes and the multiple lower cooling air outlet pipes are installed in the rear enhanced cooling section. The multiple upper cooling air outlet pipes are located above the conveying device and are arranged in sequence at intervals along the conveying direction of the conveying device. The multiple lower cooling air outlet pipes are located above the conveying device and are arranged in sequence at intervals along the conveying direction of the conveying device. Each upper cooling air outlet pipe and each lower cooling air outlet pipe is provided with one or more long strip air outlet holes.

[0012] The outlet direction of each long strip air outlet hole is toward the conveying device and is inclined against the conveying direction of the conveying device.

[0013] Each upper cooling air outlet pipe and each lower cooling air outlet pipe are installed through the furnace walls on both sides of the rear enhanced cooling section, and each upper cooling air outlet pipe and each lower cooling air outlet pipe are provided with a plurality of long strip air outlet holes of the same width; both ends of each upper cooling air outlet pipe and each lower cooling air outlet pipe are connected to the cold air supply mechanism, and the plurality of long strip air outlet holes on each upper cooling air outlet pipe are arranged in sequence at intervals along the direction from one end to the other end of the upper cooling air outlet pipe, and the length of the long strip air outlet holes located in the middle of the upper cooling air outlet pipe is greater than the length of the long strip air outlet holes located at both ends of the upper cooling air outlet pipe; the plurality of long strip air outlet holes on each lower cooling air outlet pipe are arranged in sequence at intervals along the direction from one end to the other end of the lower cooling air outlet pipe, and the length of the long strip air outlet holes located in the middle of the lower cooling air outlet pipe is greater than the length of the long strip air outlet holes located at both ends of the lower cooling air outlet pipe.

[0014] The roller kiln system is also provided with an exhaust assembly for exhausting the gas in the post-enhanced cooling section.

[0015] The exhaust assembly includes an exhaust fan and an exhaust port arranged in the rear enhanced cooling section. The exhaust fan is connected to the exhaust port through an exhaust pipeline. The exhaust pipeline is provided with a control valve for controlling the on-off of the exhaust pipeline.

[0016] An air cooling jacket is arranged inside the furnace body and furnace wall of the heat preservation section, and the air cooling jacket has an air cooling cavity, and the air cooling cavity is connected with a cold air inlet pipe and an air outlet pipe.

[0017] A plurality of air inlets are arranged at the bottom and / or the side of the temperature rising section, the temperature keeping section, the front temperature falling section and the rear enhanced temperature falling section.

[0018] The sagger is a recrystallized silicon carbide part with a SiC content of more than 99%.

[0019] The conveying device comprises a plurality of conveying rollers installed in the furnace and a driving mechanism for driving the plurality of conveying rollers to rotate. The conveying rollers are recrystallized silicon carbide parts with a SiC content of more than 99%.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The roller kiln system of the present invention is provided with a front cooling section and a rear enhanced cooling section, and is provided with a cooling air intake assembly for introducing cooling gas into the rear enhanced cooling section. During production, cooling gas (air or process gas) can be introduced into the rear enhanced cooling section through the cooling air intake assembly, and convective heat exchange can be performed with the material in the rear enhanced cooling section, so that rapid cooling and temperature reduction can be achieved, thereby improving the production efficiency of the roller kiln system. The roller kiln system only needs to add a rear enhanced cooling section and a cooling air intake assembly on the basis of the existing kiln equipment, and its cost is low and it is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the main structure of the roller kiln system.

[0023] Figure 2 It is a schematic diagram of the main structure of the front cooling section and the rear enhanced cooling section.

[0024] Figure 3 It is a schematic diagram of the side cross-sectional structure of the post-enhancement cooling section.

[0025] Figure 4 It is a schematic diagram of the partially enlarged structure of the exhaust direction of the long strip exhaust hole.

[0026] Figure 5 This is a schematic diagram of the main structure of the upper cooling outlet pipe.

[0027] Legend:

[0028] 1. Furnace body; 11. Furnace chamber; 101. Heating section; 102. Insulating section; 103. Front cooling section; 104. Rear enhanced cooling section; 2. Sagger; 3. Conveying device; 31. Conveying roller; 4. Upper cooling air outlet pipe; 5. Lower cooling air outlet pipe; 6. Long strip air outlet; 7. Exhaust port; 8. Exhaust pipeline. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 and Figure 2 As shown, the roller kiln system of this embodiment comprises a furnace body 1 having a furnace 11, a sagger 2 for containing materials, and a conveying device 3 installed in the furnace 11 for conveying the sagger 2. The furnace 11 comprises a heating section 101, a heat preservation section 102, a front cooling section 103 and a rear enhanced cooling section 104 which are sequentially connected along the conveying direction of the conveying device 3. Figure 1 The middle arrow A indicates the conveying direction of the conveying device 3. A heating assembly is provided in the heating section 101 and the heat preservation section 102. The roller kiln system is also provided with a cooling air intake assembly for introducing cooling gas into the rear enhanced cooling section 104. The roller kiln system is provided with a front cooling section 103 and a rear enhanced cooling section 104 at the same time, and is provided with a cooling air intake assembly for introducing cooling gas into the rear enhanced cooling section 104. During production, the cooling gas (air or process gas) can be introduced into the rear enhanced cooling section 104 through the cooling air intake assembly, and convective heat exchange is performed with the material in the rear enhanced cooling section 104, so that rapid cooling and cooling can be achieved, thereby improving the production efficiency of the roller kiln system. The roller kiln system only needs to add the rear enhanced cooling section 104 and the cooling air intake assembly on the basis of the existing kiln equipment, and its cost is low and easy to manufacture.

[0031] In this embodiment, Figure 2 and Figure 3 As shown, the cooling air intake assembly includes a plurality of upper cooling air outlet pipes 4, a plurality of lower cooling air outlet pipes 5, and a cold air supply mechanism for supplying cooling gas to each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5. The cold air supply mechanism is a prior art, which includes a cold air source and a fan. The cold air source is connected through the air inlet of the fan, and the air outlet of the fan is connected to each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 through a pipeline. The plurality of upper cooling air outlet pipes 4 and the plurality of lower cooling air outlet pipes 5 are installed in the rear enhanced cooling section 104. The plurality of upper cooling air outlet pipes 4 are located above the conveying device 3 and are arranged in sequence at intervals along the conveying direction of the conveying device 3. The plurality of lower cooling air outlet pipes 5 are located above the conveying device 3 and are arranged in sequence at intervals along the conveying direction of the conveying device 3. Each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 are provided with one or more long strip air outlet holes 6. Since a plurality of upper cooling air outlet pipes 4 and a plurality of lower cooling air outlet pipes 5 are respectively provided above and below the conveying device 3, the cooling efficiency is high; the plurality of upper cooling air outlet pipes 4 and the plurality of lower cooling air outlet pipes 5 are arranged in sequence and at intervals along the conveying direction of the conveying device 3, so that the cooling gas can enter the rear enhanced cooling section 104 more evenly, which is beneficial to improving the cooling effect and reducing the influence on the temperature balance in the furnace 11. Preferably, the plurality of upper cooling air outlet pipes 4 and the plurality of lower cooling air outlet pipes 5 are arranged in sequence and at intervals along the conveying direction of the conveying device 3; each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 is provided with one or more long strip air outlet holes 6, and the long strip air outlet holes 6 can further enable the cooling gas to enter the rear enhanced cooling section 104 more evenly, which can further improve the cooling effect.

[0032] In this embodiment, Figure 4 As shown, the outlet direction of each long strip outlet hole 6 is toward the conveying device 3 and is tilted against the conveying direction of the conveying device 3. That is, the outlet direction of the long strip outlet hole 6 of the upper cooling outlet pipe 4 is tilted downward against the conveying direction of the conveying device 3, and the outlet direction of the long strip outlet hole 6 of the lower cooling outlet pipe 5 is tilted upward against the conveying direction of the conveying device 3, see Figure 4 , arrow A indicates the conveying direction of the conveying device 3, arrow B indicates the outlet direction of the long strip outlet hole 6 of the upper cooling outlet pipe 4, and arrow C indicates the outlet direction of the long strip outlet hole 6 of the lower cooling outlet pipe 5. In this way, the contact heat exchange time between the cooling gas and the sagger 2 and the material in the sagger 2 is longer, which is conducive to sufficient and rapid cooling and improving the cooling effect. Preferably, the angle between the outlet direction of each long strip outlet hole 6 and the conveying direction of the conveying device 3 is 35° to 60°, and the cooling effect is best. The outlet direction of each of the above-mentioned long strip outlet holes 6 is controlled by setting the direction of the long strip outlet holes 6.

[0033] In this embodiment, each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 are installed and arranged to penetrate the furnace walls on both sides of the rear enhanced cooling section 104, and each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 are provided with a plurality of long strip air outlet holes 6 of the same width; both ends of each upper cooling air outlet pipe 4 and each lower cooling air outlet pipe 5 are connected to the cold air supply mechanism, so that the cooling gas is simultaneously introduced from both ends of the upper cooling air outlet pipe 4 and the lower cooling air outlet pipe 5. The plurality of long strip air outlet holes 6 on each upper cooling air outlet pipe 4 are arranged in sequence and spaced from one end to the other end of the upper cooling air outlet pipe 4, and the length of the long strip air outlet hole 6 located in the middle of the upper cooling air outlet pipe 4 is greater than the length of the long strip air outlet holes 6 located at both ends of the upper cooling air outlet pipe 4 (see Figure 5 ); the plurality of long strip outlet holes 6 on each lower cooling outlet pipe 5 are arranged in sequence from one end to the other end of the lower cooling outlet pipe 5, and the length of the long strip outlet hole 6 located in the middle of the lower cooling outlet pipe 5 is greater than the length of the long strip outlet holes 6 located at both ends of the lower cooling outlet pipe 5. The length of the long strip outlet holes 6 in the middle of the upper cooling outlet pipe 4 and the lower cooling outlet pipe 5 is relatively large, and the outlet speed of each long strip outlet hole 6 on the upper cooling outlet pipe 4 and the lower cooling outlet pipe 5 is consistent, so that the cooling gas entering the rear enhanced cooling section 104 is uniform, which is conducive to improving the cooling effect and reducing the influence on the temperature balance in the furnace 11.

[0034] In this embodiment, the roller kiln system is further provided with an exhaust assembly for exhausting the gas in the rear enhanced cooling section 104. The exhaust assembly directly exhausts the cooling gas entering the rear enhanced cooling section 104, thereby preventing the cooling gas entering the rear enhanced cooling section 104 from entering the insulation section 102 and the heating section 101 in large quantities and disturbing the temperature balance of the entire furnace 11, and also reduces the power required by the heating assembly to maintain the set temperature in the insulation section 102 and the heating section 101, thereby achieving the purpose of reducing energy consumption.

[0035] In this embodiment, Figure 3 As shown, the exhaust assembly includes an exhaust fan (not shown) and an exhaust port 7 provided in the rear enhanced cooling section 104. The exhaust fan is connected to the exhaust port 7 through an exhaust pipeline 8. The exhaust pipeline 8 is provided with a control valve for controlling the on-off of the exhaust pipeline 8. The control valve adopts an ordinary gate valve. The control valve can be opened or closed according to needs. When the control valve is opened, the cooling gas is discharged from the exhaust pipeline 8 under the action of the exhaust fan after heat exchange with the material; when the control valve is closed, the cooling gas is further moved to the front cooling section 103 and the insulation section 102 of the furnace 11 after heat exchange with the material. At this time, the rear enhanced cooling section 104 also plays the role of preheating the gas.

[0036] In this embodiment, an air cooling jacket is provided in the furnace wall of the furnace body 1 of the heat preservation section 102, and the air cooling jacket has an air cooling cavity, and the air cooling cavity is connected with a cold air inlet pipe and an air outlet pipe. Cooling gas is introduced into the air cooling cavity through the cold air inlet pipe, and the air outlet pipe discharges the gas in the air cooling cavity, which can strengthen the cooling of the air and materials in the post-enhanced cooling section 104, and further improve the cooling efficiency.

[0037] In this embodiment, the bottom and / or side of the temperature rising section 101, the heat preservation section 102, the front temperature falling section 103 and the rear enhanced temperature falling section 104 are provided with a plurality of air inlets to meet the process requirements of the atmosphere concentration in the furnace 11. In this embodiment, the temperature rising section 101, the heat preservation section 102, the front temperature falling section 103, the heating components and the air inlets can be set with reference to the existing kiln structure. Preferably, the heating components are heating rods, and the upper and lower sides of the conveying device 3 are provided with a plurality of heating rods arranged in sequence along the conveying direction of the conveying device 3.

[0038] In this embodiment, the sagger 2 is a recrystallized silicon carbide product with a SiC content of more than 99%, which has high corrosion resistance and high oxidation resistance, can be used for a long time in a high temperature and strong alkaline environment of 1200°C, and has a long service life. At the same time, the sagger 2 has a thermal conductivity (up to 10W / m.°C), which can improve the cooling effect.

[0039] In this embodiment, the conveying device 3 includes a plurality of conveying rollers 31 installed in the furnace 11 and a driving mechanism for driving the plurality of conveying rollers 31 to rotate. The arrangement of the conveying rollers 31 and the driving mechanism can refer to the existing roller kiln. The conveying rollers 31 are recrystallized silicon carbide parts with a SiC content of more than 99%, and have good structural stability and high corrosion resistance in a strong alkaline environment.

[0040] In this embodiment, preferably, a plurality of pressure sensors for detecting the pressure in the furnace 11 in real time are provided in the furnace 11 .

[0041] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A roller kiln system, comprising a furnace body (1) having a furnace (11), a sagger (2) for containing materials, and a conveying device (3) installed in the furnace (11) for conveying the sagger (2), characterized in that: The furnace (11) comprises a heating section (101), a heat preservation section (102), a front temperature reduction section (103) and a rear enhanced temperature reduction section (104) which are sequentially connected along the conveying direction of the conveying device (3); a heating component is provided in the heating section (101) and the heat preservation section (102); and the roller kiln system is further provided with a cooling air intake component for introducing cooling gas into the rear enhanced temperature reduction section (104); The cooling air intake assembly comprises a plurality of upper cooling air outlet pipes (4), a plurality of lower cooling air outlet pipes (5), and a cold air supply mechanism for supplying cooling air to each of the upper cooling air outlet pipes (4) and each of the lower cooling air outlet pipes (5); the plurality of upper cooling air outlet pipes (4) and the plurality of lower cooling air outlet pipes (5) are installed in the rear enhanced cooling section (104); the plurality of upper cooling air outlet pipes (4) are located above the conveying device (3) and are arranged in sequence at intervals along the conveying direction of the conveying device (3); the plurality of lower cooling air outlet pipes (5) are located above the conveying device (3) and are arranged in sequence at intervals along the conveying direction of the conveying device (3); each of the upper cooling air outlet pipes (4) and each of the lower cooling air outlet pipes (5) is provided with at least one long strip air outlet hole (6); Each upper cooling air outlet pipe (4) and each lower cooling air outlet pipe (5) are installed and arranged on the furnace walls on both sides of the rear enhanced cooling section (104); each upper cooling air outlet pipe (4) and each lower cooling air outlet pipe (5) are provided with a plurality of long strip air outlet holes (6) of the same width; both ends of each upper cooling air outlet pipe (4) and each lower cooling air outlet pipe (5) are connected to a cold air supply mechanism; the plurality of long strip air outlet holes (6) on each upper cooling air outlet pipe (4) are arranged in sequence from one end to the other end of the upper cooling air outlet pipe (4). The plurality of elongated air outlet holes (6) on each lower cooling air outlet pipe (5) are arranged in sequence at intervals along a direction from one end to the other end of the lower cooling air outlet pipe (5), and the length of the elongated air outlet holes (6) located in the middle of the upper cooling air outlet pipe (4) is greater than the length of the elongated air outlet holes (6) located at both ends of the lower cooling air outlet pipe (5); The roller kiln system is also provided with an exhaust assembly for exhausting the gas in the post-enhanced cooling section (104).

2. The roller kiln system according to claim 1, characterized in that: The outlet direction of each long strip air outlet hole (6) is toward the conveying device (3) and is arranged obliquely opposite to the conveying direction of the conveying device (3).

3. The roller kiln system according to claim 1, characterized in that: The exhaust assembly comprises an exhaust fan and an exhaust port (7) provided in the rear enhanced cooling section (104); the exhaust fan is connected to the exhaust port (7) via an exhaust pipeline (8); and a control valve for controlling the on-off of the exhaust pipeline (8) is provided on the exhaust pipeline (8).

4. The roller kiln system according to claim 1, characterized in that: An air cooling jacket is provided inside the furnace wall of the furnace body (1) of the heat preservation section (102), wherein the air cooling jacket has an air cooling cavity, and the air cooling cavity is connected to a cold air inlet pipe and an air outlet pipe.

5. The roller kiln system according to claim 1, characterized in that: A plurality of air inlets are provided at the bottom and / or side of the temperature rising section (101), the temperature keeping section (102), the front temperature falling section (103) and the rear enhanced temperature falling section (104).

6. The roller kiln system according to any one of claims 1 to 5, characterized in that: The sagger (2) is a recrystallized silicon carbide part having a SiC content of more than 99%.

7. The roller kiln system according to any one of claims 1 to 5, characterized in that: The conveying device (3) comprises a plurality of conveying rollers (31) installed in the furnace (11) and a driving mechanism for driving the plurality of conveying rollers (31) to rotate, wherein the conveying rollers (31) are recrystallized silicon carbide parts having a SiC content of more than 99%.

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