Temperature control system and temperature control method of continuous graphitization furnace

Abstract

A temperature control system and method for a continuous graphitization furnace, comprising a first temperature sensor (9) for detecting the inlet water temperature of cooling water; a second temperature sensor (8) for detecting the outlet water temperature of cooling water; a cooling water flow meter (7); a first weighing mechanism (3) for measuring the feed amount of the continuous graphitization furnace; a second weighing mechanism (5) for measuring the discharge amount of the continuous graphitization furnace; a third temperature sensor (2) for measuring the temperature of the feed material; a fourth temperature sensor (4) for measuring the temperature of the discharge material; an intermediate frequency power supply controller (10); an infrared temperature measuring instrument (6) for measuring the temperature in the furnace; a PLC (11) for collecting real-time data of each temperature sensor, flow meter, first weighing mechanism, second weighing mechanism and infrared temperature measuring instrument, and controlling the output load power of the intermediate frequency power supply controller (10); the PLC (11) calculates and controls the output load power of the intermediate frequency power supply controller (10) according to the collected data.

Description

Technical Field

[0001] This invention relates to the field of graphitization furnace technology, and in particular to a temperature control system for a continuous graphitization furnace; this invention also relates to a temperature control method for a continuous graphitization furnace. Background Technology

[0002] In the field of graphitization furnace technology, although the Atchison furnace is widely used, it is an intermittent furnace with periodic production. This discontinuous production leads to drawbacks such as low capacity, quality fluctuations, high power consumption, and harsh operating environments. Therefore, continuous graphitization furnaces have become an important research and development topic and a goal pursued worldwide. Currently, there are two types of experimental continuous graphitization furnaces: one is a single-function continuous graphitization furnace, where the calcined carbon products are continuously processed to produce graphitized products; the other is a multi-functional combined furnace, namely a double-unit furnace that combines the calcination and graphitization processes, and a triple-unit furnace that combines the pressing, calcination, and graphitization processes.

[0003] A continuous graphitization furnace is a continuous thermal equipment for graphite purification. The material to be processed enters the furnace through a feeder and gradually moves to the heating zone, where it is graphitized at high temperature. Then it gradually passes through the cooling zone and finally the product is obtained through a discharger.

[0004] Continuous graphitization furnaces require continuous heating of the furnace interior during the graphitization process. Once the operating temperature is reached, a suitable thermal balance must be maintained to ensure graphitization effectiveness and production efficiency. However, traditional temperature control systems suffer from drawbacks such as significant temperature lag and large temperature fluctuations within the furnace. Summary of the Invention

[0005] The present invention aims to address at least one deficiency in the prior art. Therefore, the technical problem solved by the present invention is to provide a temperature control system for a continuous graphitization furnace and a temperature control method for a continuous graphitization furnace, which can achieve temperature stability within the continuous graphitization furnace, reduce temperature fluctuations within the furnace, and improve the quality of the graphitized products.

[0006] To address the aforementioned technical problems, this invention provides a temperature control system for a continuous graphitization furnace, comprising: a first temperature sensor installed on the main cooling water inlet pipe of the continuous graphitization furnace for detecting the inlet temperature of the cooling water; a second temperature sensor installed on the main cooling water outlet pipe of the continuous graphitization furnace for detecting the outlet temperature of the cooling water; a flow meter installed on either the main cooling water inlet pipe or the main cooling water outlet pipe of the continuous graphitization furnace for measuring the flow rate of the cooling water; a first weighing mechanism for measuring the feed amount of the continuous graphitization furnace; a second weighing mechanism for measuring the discharge amount of the continuous graphitization furnace; a third temperature sensor for measuring the temperature of the feed material of the continuous graphitization furnace; a fourth temperature sensor for measuring the temperature of the discharge material of the continuous graphitization furnace; a medium-frequency power controller for adjusting the heating power of the continuous graphitization furnace; an infrared thermometer for measuring the furnace internal temperature; and a PLC for acquiring real-time data from the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the flow meter, the first weighing mechanism, the second weighing mechanism, and the infrared thermometer, and controlling the medium-frequency power controller to adjust the heating power of the continuous graphitization furnace.

[0007] To address the aforementioned technical problems, this invention provides a temperature control method for a continuous graphitization furnace, applied to a temperature control system for a continuous graphitization furnace. The temperature control system includes a first temperature sensor installed on the main cooling water inlet pipe of the continuous graphitization furnace for detecting the inlet temperature of the cooling water; a second temperature sensor installed on the main cooling water outlet pipe of the continuous graphitization furnace for detecting the outlet temperature of the cooling water; a flow meter installed on either the main cooling water inlet pipe or the main cooling water outlet pipe of the continuous graphitization furnace for measuring the cooling water flow rate; a first weighing mechanism for measuring the feed rate of the continuous graphitization furnace; and a weighing mechanism for measuring the continuous graphitization furnace feed rate. The system includes: a second weighing mechanism for measuring the output of the graphitization furnace; a third temperature sensor for measuring the temperature of the feed material to the continuous graphitization furnace; a fourth temperature sensor for measuring the temperature of the output material from the continuous graphitization furnace; a medium-frequency power controller for adjusting the heating power of the continuous graphitization furnace; an infrared thermometer for measuring the furnace temperature; and a PLC for collecting real-time data from the first, second, third, and fourth temperature sensors, the flow meter, the first weighing mechanism, the second weighing mechanism, and the infrared thermometer, and for controlling the medium-frequency power controller to adjust the heating power of the continuous graphitization furnace. The temperature control process includes the following steps:

[0008] The data detected in real time by the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the flow meter, the first weighing mechanism, the second weighing mechanism, and the infrared thermometer are transmitted to the PLC.

[0009] The PLC calculates and controls the intermediate frequency power controller to adjust the heating power of the continuous graphitization furnace according to the following steps:

[0010] 1) Calculate the PID increment during the k-th iteration.

[0011] ΔU(k)=K p [e(k)-e(k-1)]+K i e(k)+K d [e(k)-2e(k-1)+e(k-2)]

[0012] Where ΔU(k) ​​is the PID increment during iterative calculation, in kW.

[0013] Kp is the proportional gain.

[0014] K i Integral gain

[0015] K d Differential gain

[0016] e(k) represents the deviation between the current temperature and the target temperature at the k-th calculation.

[0017] e(k-1) represents the deviation during the (k-1)th calculation.

[0018] e(k-2) represents the deviation during the (k-2)th calculation.

[0019] Deviation e is the difference between the target temperature value and the current temperature value, in °C;

[0020] 2) Calculate the output value of the PID controller:

[0021] U(k) = U(k-1) + ΔU(k)

[0022] Where U(k) is the PID output calculated in the kth iteration, in kW.

[0023] U(k-1) is the output of the (k-1)th calculation, in kW.

[0024] ΔU(k) ​​is the output increment during the k-th iteration, in kW;

[0025] 3) Calculate the difference between the heat input power and the heat output power of the continuous graphitization furnace.

[0026] ΔP=P0-P1-P2

[0027] Where P0 is the heating power output from the intermediate frequency power supply to the continuous graphitization furnace during the detection time, in kW.

[0028] P1 is the cooling water heat dissipation power, calculated using the following formula:

[0029] P1=c1f1ρ1Δt1

[0030] In the formula, c1 is the specific heat capacity of water, in kJ / (kg*℃).

[0031] f1 is the cooling water flow rate, in meters (m³). 3 / s

[0032] ρ1 is the density of water, in kg / m³. 3

[0033] Δt1 is the difference between the cooling water outlet temperature and the cooling water inlet temperature, in °C.

[0034] P2 is the heat dissipation power of the material, calculated using the following formula:

[0035] P2 = c2(f3t3 - f2t2)

[0036] In the formula, c2 is the specific heat capacity of the material, in kJ / (kg*℃).

[0037] f3 represents the material discharge speed, in kg / s.

[0038] f2 is the material feed rate, in kg / s.

[0039] t3 and t2 are the material discharge temperature and feed temperature, respectively, in °C.

[0040] If the difference between the heat input power and heat output power of the continuous graphitization furnace is ΔP>0, the input power is greater than the heat dissipation output power, and the PLC issues a command to reduce the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP<0, the input power is less than the heat dissipation output power, and the PLC issues a command to increase the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP=0, the PLC does not need to issue a command to adjust the heating power output by the intermediate frequency power supply to the continuous graphitization furnace.

[0041] 4) The PLC calculates and controls the heating power P output by the intermediate frequency power controller to the continuous graphitization furnace according to the following formula. out :

[0042] P out =U(k)-b×ΔP

[0043] Where P out This represents the heating power output from the intermediate frequency power controller to the continuous graphitization furnace, in kW. 'b' is a correction factor.

[0044] The value range is 0.5 ≤ b ≤ 0.8.

[0045] The technical solution provided by this invention introduces heat balance calculation to calculate the difference between the heat input power and output power of the graphitization furnace in real time, and then corrects the output value of the temperature PID control, thereby improving the furnace temperature control accuracy and reducing furnace temperature fluctuations. This enables the stabilization of the heating temperature in the continuous graphitization furnace, maintaining a stable production process, ensuring graphitization quality, reducing temperature fluctuations within the continuous graphitization furnace, and extending the service life of the equipment. Attached Figure Description

[0046] The accompanying drawings are provided to further illustrate the invention and form part of this application, but do not constitute an undue limitation of the invention. In the drawings:

[0047] Figure 1 This is a schematic diagram of the temperature control system of the continuous graphitization furnace in the embodiment. Detailed Implementation

[0048] The present invention will be further described below with reference to the embodiments.

[0049] like Figure 1 As shown, the temperature control system of the continuous graphitization furnace includes: a first temperature sensor 9 installed on the main cooling water inlet pipe of the continuous graphitization furnace 1 for detecting the inlet temperature of the cooling water; a second temperature sensor 8 installed on the main cooling water outlet pipe of the continuous graphitization furnace for detecting the outlet temperature of the cooling water; a flow meter 7 installed on either the main cooling water inlet pipe or the main cooling water outlet pipe of the continuous graphitization furnace for measuring the flow rate of the cooling water; a first weighing mechanism 3 for measuring the feed rate of the continuous graphitization furnace; a second weighing mechanism 5 for measuring the discharge rate of the continuous graphitization furnace; and a third weighing mechanism for measuring the temperature of the continuous graphitization furnace. The system includes: a third temperature sensor 2 for measuring the temperature of the feed material; a fourth temperature sensor 4 for measuring the temperature of the discharge material from the continuous graphitization furnace; a medium-frequency power controller 10 for adjusting the heating power of the continuous graphitization furnace; an infrared thermometer 6 for measuring the temperature inside the furnace; and a PLC 11 for collecting real-time data from the first temperature sensor 9, the second temperature sensor 8, the third temperature sensor 2, the fourth temperature sensor 4, the flow meter 7, the first weighing mechanism 3, the second weighing mechanism 5, and the infrared thermometer 6, and for controlling the medium-frequency power controller 10 to adjust the heating power of the continuous graphitization furnace.

[0050] The temperature control process includes the following steps:

[0051] The data detected in real time by the first temperature sensor 9, the second temperature sensor 8, the third temperature sensor 2, the fourth temperature sensor 4, the flow meter 7, the first weighing mechanism 3, the second weighing mechanism 5, and the infrared thermometer 6 are transmitted to the PLC 11.

[0052] The PLC11 calculates and controls the intermediate frequency power controller 10 to adjust the heating power of the continuous graphitization furnace according to the following steps:

[0053] 1) Calculate the PID increment during the k-th iteration.

[0054] ΔU(k)=K p [e(k)-e(k-1)]+K i e(k)+K d [e(k)-2e(k-1)+e(k-2)]

[0055] Where ΔU(k) ​​is the PID increment during iterative calculation, in kW.

[0056] Kp is the proportional gain.

[0057] K i Integral gain

[0058] K d Differential gain

[0059] e(k) represents the deviation between the current temperature and the target temperature at the k-th calculation.

[0060] e(k-1) represents the deviation during the (k-1)th calculation.

[0061] e(k-2) represents the deviation during the (k-2)th calculation.

[0062] Deviation e is the difference between the target temperature value and the current temperature value, in °C;

[0063] 2) Calculate the output value of the PID controller:

[0064] U(k) = U(k-1) + ΔU(k)

[0065] Where U(k) is the PID output calculated in the kth iteration, in kW.

[0066] U(k-1) is the output of the (k-1)th calculation, in kW.

[0067] ΔU(k) ​​is the output increment during the k-th iteration, in kW;

[0068] 3) Calculate the difference between the heat input power and the heat output power of the continuous graphitization furnace.

[0069] ΔP=P0-P1-P2

[0070] Where P0 is the heating power output from the intermediate frequency power supply to the continuous graphitization furnace during the detection time, in kW.

[0071] P1 is the cooling water heat dissipation power, calculated using the following formula:

[0072] P1=c1f1ρ1Δt1

[0073] Where c1 is the specific heat capacity of water, with the unit kJ / (kg*℃).

[0074] f1 is the flow rate of cooling water, with the unit m 3 / s

[0075] ρ1 is the density of water, with the unit kg / m 3

[0076] Δt1 is the difference between the outlet temperature and the inlet temperature of the cooling water, with the unit ℃.

[0077] P2 is the heat dissipation power of the material, and the calculation formula is as follows:

[0078] P2 = c2(f3t3 - f2t2)

[0079] Where c2 is the specific heat capacity of the material, with the unit kJ / (kg*℃).

[0080] f3 is the discharging speed of the material, with the unit kg / s

[0081] f2 is the feeding speed of the material, with the unit kg / s

[0082] t3 and t2 are the discharging temperature and the feeding temperature of the material respectively, with the unit ℃.

[0083] If the difference ΔP between the heat input power and the heat output power of the continuous graphitization furnace is > 0, that is, the input power is greater than the heat dissipation output power, then PLC11 issues an instruction to reduce the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP < 0, that is, the input power is less than the heat dissipation output power, then PLC11 issues an instruction to increase the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP = 0, then PLC11 does not need to issue an instruction to adjust the heating power output by the intermediate frequency power supply to the continuous graphitization furnace.

[0084] 4) PLC11 calculates and controls the heating power P output by the intermediate frequency power supply controller 10 to the continuous graphitization furnace according to the following formula out :

[0085] P out = U(k) - b×ΔP

[0086] Where P out is the heating power output by the intermediate frequency power supply controller 10 to the continuous graphitization furnace, with the unit kW, b is the correction coefficient, and its value range is 0 < b ≤ 1. The larger its value, the stronger the correction effect. According to experiments, it is better to take the value range of 0.5 ≤ b ≤ 0.8.

[0087] The technical solution provided by this invention introduces heat balance calculation to calculate the difference between the heat input power and output power of the graphitization furnace in real time, and then corrects the output value of the temperature PID control, thereby improving the furnace temperature control accuracy and reducing furnace temperature fluctuations. This enables the stabilization of the heating temperature in the continuous graphitization furnace, maintaining a stable production process, ensuring graphitization quality, reducing temperature fluctuations within the continuous graphitization furnace, and extending the service life of the equipment.

[0088] This invention is not limited to the preferred embodiments described above. Various modifications and improvements can be made within the spirit of the claims and specification to solve the same technical problem and achieve the desired technical effect; therefore, these will not be repeated. All solutions that can be directly or indirectly conceived by those skilled in the art from the disclosure of this invention, as long as they fall within the spirit of the claims, are also within the scope of protection of this invention.

Claims

1. A temperature control method for a continuous graphitization furnace, applied to the temperature control system of a continuous graphitization furnace, characterized in that, The temperature control system of the continuous graphitization furnace includes a first temperature sensor (9) installed on the main cooling water inlet pipe of the continuous graphitization furnace (1) for detecting the inlet temperature of the cooling water; a second temperature sensor (8) installed on the main cooling water outlet pipe of the continuous graphitization furnace for detecting the outlet temperature of the cooling water; a flow meter (7) installed on the main cooling water inlet pipe or main cooling water outlet pipe of the continuous graphitization furnace for measuring the flow rate of the cooling water; a first weighing mechanism (3) for measuring the feed amount of the continuous graphitization furnace; a second weighing mechanism (5) for measuring the discharge amount of the continuous graphitization furnace; and a third temperature sensor (2) for measuring the temperature of the feed material of the continuous graphitization furnace. ); a fourth temperature sensor (4) for measuring the temperature of the material discharged from the continuous graphitization furnace; a medium-frequency power controller (10) for adjusting the heating power of the continuous graphitization furnace; an infrared thermometer (6) for measuring the temperature inside the furnace; a PLC (11) for collecting real-time data from the first temperature sensor (9), the second temperature sensor (8), the third temperature sensor (2), the fourth temperature sensor (4), the flow meter (7), the first weighing mechanism (3), the second weighing mechanism (5), and the infrared thermometer (6), and controlling the medium-frequency power controller (10) to adjust the heating power of the continuous graphitization furnace; the temperature control process includes the following steps: The data detected in real time by the first temperature sensor (9), the second temperature sensor (8), the third temperature sensor (2), the fourth temperature sensor (4), the flow meter (7), the first weighing mechanism (3), the second weighing mechanism (5) and the infrared thermometer (6) are transmitted to the PLC (11). The PLC (11) calculates and controls the intermediate frequency power controller (10) to adjust the heating power of the continuous graphitization furnace according to the following steps: 1) Calculate the PID increment during the k-th iteration. Where ΔU(k) ​​is the PID increment during iterative calculation, in kW. Kp is the proportional gain. K i For integral gain K d Differential gain e(k) represents the deviation between the current temperature and the target temperature at the k-th calculation. e(k-1) represents the deviation during the (k-1)th calculation. e(k-2) represents the deviation during the (k-2)th calculation. Deviation e is the difference between the target temperature value and the current temperature value, in °C; 2) Calculate the output value of the PID controller: Where U(k) is the PID output calculated in the kth iteration, in kW. U(k-1) is the output of the (k-1)th calculation, in kW. ΔU(k) ​​is the output increment during the k-th iteration, in kW; 3) Calculate the difference between the heat input power and the heat output power of the continuous graphitization furnace. Where P0 is the heating power output from the intermediate frequency power supply to the continuous graphitization furnace during the detection time, in kW. P1 is the cooling water heat dissipation power, calculated using the following formula: In the formula, c1 is the specific heat capacity of water, in kJ / (kg*℃). f1 is the cooling water flow rate, in meters (m³). 3 / s ρ1 is the density of water, in kg / m³. 3 Δt1 is the difference between the cooling water outlet temperature and the cooling water inlet temperature, in °C. P2 is the heat dissipation power of the material, calculated using the following formula: In the formula, c2 is the specific heat capacity of the material, in kJ / (kg*℃). f3 represents the material discharge speed, in kg / s. f2 is the material feed rate, in kg / s. t3 and t2 are the material discharge temperature and feed temperature, respectively, in °C. If the difference between the heat input power and heat output power of the continuous graphitization furnace is ΔP>0, and the input power is greater than the heat dissipation output power, then PLC (11) issues an instruction to reduce the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP<0, and the input power is less than the heat dissipation output power, then PLC (11) issues an instruction to increase the heating power output by the intermediate frequency power supply to the continuous graphitization furnace; if ΔP=0, then PLC (11) does not need to issue an instruction to adjust the heating power output by the intermediate frequency power supply to the continuous graphitization furnace. 4) The PLC (11) calculates and controls the heating power P output by the intermediate frequency power controller (10) to the continuous graphitization furnace according to the following formula. out : Where P out The heating power output by the medium frequency power controller (10) to the continuous graphitization furnace is in kW, and b is a correction coefficient with a value range of 0.5≤b≤0.8.

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