Double kiln hot air circulation system

Abstract

The utility model provides a kind of double kiln hot air circulation system, including first kiln, second kiln and hot air circulation pipe network;Second kiln is side by side arranged in the first kiln side, and with the operation cycle of the first kiln each other staggered;Hot air circulation pipe network includes complementary air path, it is connected between the first kiln with the second kiln;Wherein, the first kiln and second kiln are divided into at least four temperature control zones along material advancing direction, including preheating zone, at least one medium temperature zone, high temperature zone and cooling zone, each the temperature control zone is provided with and the air inlet and outlet that can switch on-off are connected with the complementary air path.

Description

Technical Field

[0001] This utility model relates to the field of industrial kiln technology, specifically to a dual-kiln hot air circulation system. Background Technology

[0002] Industrial kilns, such as roller kilns and tunnel kilns, are core thermal equipment in the production of ceramics, refractory materials, and lithium battery cathode and anode materials, and are also high-energy-consuming equipment. Their traditional operating mode is typically a single kiln operating independently, with materials moving from the feed end (cold end) to the discharge end (hot end) of the kiln, undergoing preheating, heating, firing, and cooling processes within the kiln. For example, Chinese Patent 201911395465.0 discloses a roller kiln, including a furnace body with a furnace chamber, a conveying device and a heating device installed inside the furnace chamber, and a temperature-regulating air inlet device within the furnace chamber where the air outlet velocity at the center of the furnace chamber is greater than the air outlet velocity at the sides of the furnace chamber.

[0003] To recover and utilize this waste heat, several improved solutions have been proposed in existing technologies. A common approach is to install a heat exchanger at the end of the kiln's exhaust duct or cooling zone to preheat the combustion air or process gas using the waste gas. While this method can recover some energy, the recovery efficiency is limited, and it fails to achieve deep coupling and system optimization with the energy requirements of the kiln's core heating process, resulting in a serious mismatch between energy utilization quality and efficiency. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a dual-kiln hot air circulation system to solve the technical problem that the existing technology fails to achieve deep coupling and system optimization with the energy demand of the core heating process of the kiln, resulting in a serious mismatch in energy utilization quality.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: This utility model provides a dual-kiln hot air circulation system, including: The first kiln; The second kiln is arranged side-by-side with the first kiln on one side, and its operating cycle is staggered from that of the first kiln; and The hot air circulation network includes a complementary air path connected between the first kiln and the second kiln. The first and second kilns are divided into at least four temperature control zones along the material travel direction, including a preheating zone, at least one medium-temperature zone, a high-temperature zone, and a cooling zone. Each temperature control zone is provided with an inlet and outlet air vent connected to the complementary air path and switchable on / off. The complementary air path is used to guide the hot exhaust gas from the high-temperature zone and the medium-temperature zone of the kiln in the kiln exiting stage to the medium-temperature zone and the preheating zone of the kiln in the kiln entering stage, respectively.

[0006] In some embodiments, the complementary air path includes a first air path, a second air path, a third air path, and a fourth air path. The first air path connects the preheating zone of the first kiln and the medium-temperature zone of the second kiln. The second air path connects the medium-temperature zone of the first kiln and the high-temperature zone of the second kiln. The third air path connects the medium-temperature zone of the first kiln and the preheating zone of the second kiln. The fourth air path connects the high-temperature zone of the first kiln and the medium-temperature zone of the second kiln.

[0007] In some embodiments, the air inlet and outlet are equipped with air valves, and the first air path, the second air path, the third air path and the fourth air path are each equipped with a fan.

[0008] In some embodiments, a temperature sensor is provided within the temperature control zone.

[0009] In some embodiments, a central control unit is also included. The temperature sensor is electrically connected to the central control unit, and the fan and the air valve are both electrically connected to the central control unit. The central control unit dynamically adjusts the opening degree of the air valve and the frequency of the fan in the main complementary air path based on the difference between the real-time temperature and the target temperature fed back by the temperature sensors of each temperature control zone of the first kiln and the second kiln.

[0010] In some embodiments, a combustion air path is also included. The combustion air path is installed on one side of the kiln and is equipped with a heat exchange pipe. The heat exchange pipe is connected to each of the preheating zones and passes through the combustion air path. It is used to discharge the exhaust gas whose temperature has been significantly reduced after heat exchange in the preheating zone and to preheat the combustion air.

[0011] In some embodiments, the hot air circulation network further includes internal circulation air paths, which are respectively arranged on the first kiln and the second kiln, for adjusting hot air between different temperature control zones within the kiln.

[0012] In some embodiments, the internal circulating air path includes a first pipe, a second pipe, a third pipe, a fourth pipe, and an induced draft fan. The two ends of the first pipe are respectively connected to the high-temperature zone and the air inlet of the induced draft fan. The second and third pipes are both connected to the medium-temperature zone and are respectively connected to the air inlet and air outlet of the induced draft fan. The fourth pipe is respectively connected to the preheating zone and the air outlet of the induced draft fan.

[0013] In some embodiments, control valves are provided on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline respectively.

[0014] In some embodiments, both the control valve and the induced draft fan are electrically connected to the central control unit.

[0015] Compared with existing technologies, the dual-kiln hot air circulation system provided by this utility model complements the two kilns, adopts a gradient temperature zone layout and cascaded waste heat utilization, matches the high-temperature waste gas from the kiln exiting the kiln with the medium-temperature zone requirements of the kiln entering the kiln, and matches the medium-temperature waste gas from the kiln exiting the kiln with the preheating zone requirements of the kiln entering the kiln, thus achieving temperature matching and cascaded utilization, greatly reducing the loss of high-quality heat energy in the mixing process, and maximizing energy utilization. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the dual-kiln hot air circulation system provided in this embodiment of the utility model; Figure 2 This is a simplified structural diagram of the dual-kiln hot air circulation system provided in this embodiment of the utility model; Figure 3 This is a control block diagram of the dual-kiln hot air circulation system provided in this embodiment of the utility model.

[0017] Explanation of reference numerals in the attached figures: 1. The first kiln; 2. Second kiln; 3. Hot air circulation duct network; 301. Preheating zone; 302. Medium temperature zone; 303. High temperature zone; 304. Cooling zone; 31. Complementary air duct; 311. First air duct; 312. Second air duct; 313. Third air duct; 314. Fourth air duct; 315. Air valve; 316. Temperature sensor; 317. Fan; 32. Internal circulation air duct; 321. First duct; 322. Second duct; 323. Third duct; 324. Fourth duct; 325. Exhaust fan; 326. Control valve; 4. Central control unit; 5. Combustion air duct; 51. Heat exchange pipeline. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] To address the technical problem of severe mismatch between energy utilization quality and the failure to deeply couple and optimize the system to meet the energy demands of the core heating process of the kiln, this utility model provides a dual-kiln hot air circulation system. This system achieves complementary operation between the two kilns, employs a gradient temperature zone layout and cascaded waste heat utilization, matches the high-temperature waste gas exiting the kiln with the medium-temperature waste gas entering the kiln, and matches the medium-temperature waste gas exiting the kiln with the preheating zone waste gas entering the kiln. This achieves temperature matching and tiered utilization, greatly reducing the loss of high-quality heat energy during the mixing process and maximizing energy utilization.

[0020] It should be noted that the dual-kiln hot air circulation system described in this utility model is used for, but not limited to, lithium battery positive and negative electrode materials. For ease of explanation, this utility model only uses the application of the dual-kiln hot air circulation system to lithium battery positive and negative electrode materials as an example for explanation. The principle of the dual-kiln hot air circulation system applied to other types of equipment is essentially the same as that applied to lithium battery positive and negative electrode materials, and will not be described in detail here.

[0021] Please see Figure 1-3 This utility model provides a dual-kiln hot air circulation system, which includes a first kiln 1, a second kiln 2, and a hot air circulation network 3. The second kiln 2 is arranged side by side with the first kiln 1 on one side, and the material travel direction of the second kiln 1 is opposite to that of the first kiln 1. Their operating cycles are staggered, forming a dual-kiln layout. The hot air circulation network 3 includes a complementary air passage 31, which connects the first kiln 1 and the second kiln 2. The first kiln 1 and the second kiln 2 are divided into at least four temperature control zones along the material travel direction, including a preheating zone 301, at least one medium-temperature zone 302, and a high-temperature zone. Zone 303 and cooling zone 304, each of the temperature control zones, are equipped with inlet and outlet air vents connected to the complementary air path 31 and capable of being switched on and off. The complementary air path 31 is used to guide the hot waste gas from the high-temperature zone 303 and medium-temperature zone 302 of the kiln during the kiln exiting stage to the medium-temperature zone 302 and preheating zone 301 of the kiln during the kiln entering stage, respectively, for complementary waste heat utilization. This reduces the heat required for kiln entry, the heat required for heating, and heat loss, directly converting the high-temperature waste heat of one kiln into the process heat source of another kiln, fundamentally reducing the huge heat loss caused by direct emission of waste gas in the traditional mode. By matching the high-temperature waste gas from the kiln exiting the kiln with the medium-temperature zone requirements of the kiln entering the kiln, and matching the medium-temperature waste gas from the kiln exiting the kiln with the preheating zone requirements of the kiln entering the kiln, the temperature is stepped, improving energy utilization efficiency.

[0022] In one embodiment, please refer to Figure 1 and Figure 2To form specific complementary airflow paths and individual control, the complementary airflow path 31 includes a first airflow path 311, a second airflow path 312, a third airflow path 313, and a fourth airflow path 314. The first airflow path 311 connects the preheating zone 301 of the first kiln 1 and the medium-temperature zone 302 of the second kiln 2. The second airflow path 312 connects the medium-temperature zone 302 of the first kiln 1 and the high-temperature zone 303 of the second kiln 2. The third airflow path 313 connects the medium-temperature zone of the first kiln 1. Between the preheating zone 301 of the first kiln 1 and the second kiln 2, the fourth air passage 314 connects the high-temperature zone 303 of the first kiln 1 and the medium-temperature zone 302 of the second kiln 2, forming a connection between the preheating zone and the medium-temperature zone, and between the medium-temperature zone and the high-temperature zone of the two kilns. The operating cycles are staggered between the kiln inlet and the kiln outlet. The hot exhaust gas from the high-temperature zone of the kiln in the kiln outlet stage can be preferentially led to the medium-temperature zone of the kiln in the kiln inlet stage. At the same time, the hot exhaust gas from the medium-temperature zone of the kiln in the kiln outlet stage can be led to the preheating zone of the kiln in the kiln inlet stage.

[0023] Furthermore, in order to control the opening and closing of each air passage, the air inlet and outlet are equipped with air valves 315, and in order to perform air extraction and guidance, the first air passage 311, the second air passage 312, the third air passage 313 and the fourth air passage 314 are each equipped with a fan 317.

[0024] Furthermore, in order to monitor the temperature of each temperature control zone, a temperature sensor 316 is provided in the temperature control zone. The temperature sensor 316 is a high-temperature resistant temperature sensor.

[0025] For details, please refer to Figure 3 In order to provide automated logic control, a central control unit 4 is also included. The temperature sensor 316 is electrically connected to the central control unit 4, and the fan 317 and the air valve 315 are both electrically connected to the central control unit 4. The central control unit 4 dynamically adjusts the opening degree of the air valve 315 and the frequency of the fan 317 in the main complementary air path 31 according to the difference between the real-time temperature and the target temperature fed back by the temperature sensor 316 of each temperature control zone of the first kiln 1 and the second kiln 2. The system monitors the operation stages of the first and second kilns and the real-time temperatures of each temperature control zone; it determines whether the two kilns are in a complementary operation window; if so, it activates the main complementary air path and, according to the principle of cascaded waste heat utilization, directs the high-temperature hot air from the kiln exiting the kiln to the medium-temperature zone of the kiln entering the kiln, and directs the medium-temperature hot air from the kiln exiting the kiln to the preheating zone of the kiln entering the kiln; it compares the temperature of each temperature control zone with the set value in real time, and precisely controls the air volume of each branch by dynamically adjusting the air valves and fans; and it introduces the final low-temperature exhaust gas after the complementary circulation into a multi-stage waste heat recovery unit for deep utilization.

[0026] Understandably, the central control unit 4 can employ a programmable logic controller (PLC) to receive all signals from the data acquisition layer in real time, acting as a lower-level machine. It can also be equipped with an industrial-grade computer as a higher-level machine, running the SCADA data acquisition and monitoring control system and the MES manufacturing execution system interface software. In other words, the central control unit uses an existing mature control system, including a data acquisition unit, a control unit, and a monitoring and management unit. The data acquisition unit consists of temperature sensors distributed in each temperature control zone and flow and pressure sensors in each air path. The control unit, with the PLC as its core, is responsible for receiving signals from the data acquisition unit and outputting control commands to the regulating valves and variable frequency fans in each air path. The monitoring and management unit, with an industrial computer as its core, runs a human-machine interface and a dynamic heat demand map algorithm. This algorithm is used to dynamically calculate and send optimal control parameters to the control unit based on the real-time operating status of the two kilns. All of the above are existing technologies and will not be elaborated upon further here.

[0027] In one embodiment, please refer to Figure 1 and Figure 2 In order to further utilize the waste heat of the exhaust gas, a combustion air path 5 is also included. The combustion air path 5 is installed on one side of the kiln and is equipped with a heat exchange pipe 51. The heat exchange pipe 51 is connected to each of the preheating zones 301 and runs through the combustion air path 5. It is used to exhaust the exhaust gas whose temperature has been significantly reduced after heat exchange in the preheating zone 301, and to preheat the combustion air. In this way, the waste heat of the exhaust gas after heat exchange in the preheating zone can be utilized to heat the combustion air.

[0028] In one embodiment, please refer to Figure 1 and Figure 2 To achieve thermal balance within a single kiln, the hot air circulation network 3 also includes internal circulation air paths 32, which are correspondingly installed on the first kiln 1 and the second kiln 2, for distributing hot air between different temperature control zones within the kiln. When the heat in a temperature zone within the same kiln is insufficient and the main complementary air path supply is not timely, some heat can be extracted from the high-temperature zone of the same kiln to supplement it, which increases the flexibility and stability of system regulation.

[0029] Specifically, the internal circulating air path 32 includes a first pipe 321, a second pipe 322, a third pipe 323, a fourth pipe 324, and an induced draft fan 325. The two ends of the first pipe 321 are respectively connected to the high-temperature zone 303 and the air inlet of the induced draft fan 325. The second pipe 322 and the third pipe 323 are both connected to the medium-temperature zone 302 and are respectively connected to the air inlet and air outlet of the induced draft fan 325. The fourth pipe 324 is respectively connected to the preheating zone 301 and the air outlet of the induced draft fan 325, so that the high-temperature zone supplements the heat of the medium-temperature zone, or the medium-temperature zone supplements the heat of the preheating zone.

[0030] Control valves 326 are provided on the first pipeline 321, the second pipeline 322, the third pipeline 323 and the fourth pipeline 324 respectively to facilitate on / off control.

[0031] Furthermore, both the control valve 326 and the induced draft fan 325 are electrically connected to the central control unit 4, which facilitates the central control unit 4 in coordinating between the complementary air path 31 and the internal circulation air path 32.

[0032] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A dual-kiln hot air circulation system, characterized in that, include: The first kiln; The second kiln is arranged side by side with the first kiln on one side, and its operating cycle is staggered from that of the first kiln. as well as The hot air circulation network includes a complementary air path connected between the first kiln and the second kiln. The first and second kilns are divided into at least four temperature control zones along the material travel direction, including a preheating zone, at least one medium-temperature zone, a high-temperature zone, and a cooling zone. Each temperature control zone is provided with an inlet and outlet air vent connected to the complementary air path and switchable on / off. The complementary air path is used to guide the hot exhaust gas from the high-temperature zone and the medium-temperature zone of the kiln in the kiln exiting stage to the medium-temperature zone and the preheating zone of the kiln in the kiln entering stage, respectively.

2. The dual-kiln hot air circulation system according to claim 1, characterized in that, The complementary airflow path includes a first airflow path, a second airflow path, a third airflow path, and a fourth airflow path. The first airflow path connects the preheating zone of the first kiln and the medium-temperature zone of the second kiln. The second airflow path connects the medium-temperature zone of the first kiln and the high-temperature zone of the second kiln. The third airflow path connects the medium-temperature zone of the first kiln and the preheating zone of the second kiln. The fourth airflow path connects the high-temperature zone of the first kiln and the medium-temperature zone of the second kiln.

3. The dual-kiln hot air circulation system according to claim 2, characterized in that, The air inlet and outlet are equipped with air valves, and the first air path, the second air path, the third air path and the fourth air path are each equipped with a fan.

4. The dual-kiln hot air circulation system according to claim 3, characterized in that, A temperature sensor is installed in the temperature control zone.

5. The dual-kiln hot air circulation system according to claim 4, characterized in that, It also includes a central control unit, the temperature sensor is electrically connected to the central control unit, and the fan and the air valve are both electrically connected to the central control unit. The central control unit dynamically adjusts the opening degree of the air valve and the frequency of the fan in the complementary air path according to the difference between the real-time temperature and the target temperature fed back by the temperature sensors of each temperature control zone of the first kiln and the second kiln.

6. The dual-kiln hot air circulation system according to claim 1, characterized in that, It also includes a combustion air path, which is installed on one side of the kiln and equipped with a heat exchange pipe. The heat exchange pipe is connected to each of the preheating zones and runs through the combustion air path. It is used to discharge the exhaust gas whose temperature has been significantly reduced after heat exchange in the preheating zone and to preheat the combustion air.

7. The dual-kiln hot air circulation system according to claim 5, characterized in that, The hot air circulation network also includes internal circulation air paths, which are installed one-to-one on the first kiln and the second kiln, for adjusting hot air between different temperature control zones within the kiln.

8. The dual-kiln hot air circulation system according to claim 7, characterized in that, The internal circulating air path includes a first pipe, a second pipe, a third pipe, a fourth pipe, and an induced draft fan. The two ends of the first pipe are connected to the high-temperature zone and the air inlet of the induced draft fan, respectively. The second and third pipes are both connected to the medium-temperature zone and are connected to the air inlet and outlet of the induced draft fan, respectively. The fourth pipe is connected to the preheating zone and the air outlet of the induced draft fan, respectively.

9. The dual-kiln hot air circulation system according to claim 8, characterized in that, Control valves are installed on the first, second, third, and fourth pipelines respectively.

10. The dual-kiln hot air circulation system according to claim 9, characterized in that, Both the control valve and the induced draft fan are electrically connected to the central control unit.

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