Energy-saving and consumption-reducing method for producing lithium battery negative electrode material by graphitization Acheson furnace

Abstract

The invention relates to the technical field of carbon material graphitization preparation, in particular to an energy-saving and consumption-reducing method for producing a lithium battery negative electrode material by a graphitization Acheson furnace. An energy-saving and consumption-reducing method for producing a lithium battery negative electrode material by a graphitized Acheson furnace comprises the following steps: S1, acquiring an output current value and an output voltage value of a transformer, and starting natural power climbing; s2, entering a time-of-use electricity price load transfer stage after natural power climbing is finished; s3, entering an energy efficiency dynamic balance stage after the time-of-use electricity price load transfer stage is ended; and S4, entering a furnace temperature closed-loop control stage after the energy efficiency dynamic balance stage is ended. The energy efficiency of the Acheson furnace is remarkably improved through multi-stage intelligent cooperative control, dynamic power adjustment, time-of-use electricity price response, gradient charging, waste heat recovery and ash content joint control technologies, and efficient, stable, energy-saving and low-cost operation of the graphitization process is achieved.

Description

Technical Field

[0001] This invention relates to the field of graphitization preparation technology of carbon materials, and in particular to an energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitization Atchison furnace. Background Technology

[0002] The graphitization Atchison furnace is a key piece of equipment for preparing crystallized artificial graphite by high-temperature heat treatment of carbonaceous materials using the Joule heating principle. Its process efficiency directly determines the conductivity and production cost of lithium battery anode materials. Existing technologies have basically achieved automated operation of the graphitization process by setting fixed starting power, ramp rate, and target power curves, and have made progress in stabilizing the production process.

[0003] However, existing methods have significant limitations in addressing the industry's ongoing demands for cost reduction and efficiency improvement. The fixed power curve model fails to match the dynamic changes in furnace resistance, restricting the release of the transformer's output potential and resulting in a long heating phase and insufficient energy utilization. Simultaneously, the rigid control strategy fails to integrate with the grid's time-of-use pricing mechanism, hindering optimization in terms of energy costs. Furthermore, experience-based furnace loading methods easily lead to uneven distribution of current and heat field within the furnace, causing localized overheating or incomplete reactions. This not only affects the consistency of product resistivity but also results in a large amount of furnace radiant heat and high-temperature flue gas not being recovered and utilized by the system, leading to low overall energy efficiency.

[0004] Therefore, there is an urgent need for an intelligent production method that can deeply integrate process status perception, dynamic power regulation and multi-objective optimization, so as to comprehensively improve the energy efficiency, cost control and product quality stability of the graphitization process. Summary of the Invention

[0005] To overcome the shortcomings of insufficient energy efficiency synergy optimization in graphitization processes, this invention provides a method for energy saving and consumption reduction in the production of lithium battery anode materials using a graphitized Atchison furnace.

[0006] The technical implementation scheme of the present invention is: a method for energy saving and consumption reduction in the production of lithium battery anode materials using a graphitization Atchison furnace, comprising the following steps:

[0007] S1: Obtain the output current and output voltage values ​​of the transformer and begin natural power ramp-up;

[0008] S2: After the natural power ramp-up ends, the time-of-use electricity load transfer phase begins;

[0009] S3: After the time-of-use electricity price load transfer phase ends, the energy efficiency dynamic balance phase begins;

[0010] S4: After the energy efficiency dynamic balance stage ends, the furnace temperature closed-loop control stage begins.

[0011] S5: After the furnace temperature closed-loop control stage ends, the intelligent joint control stage of furnace temperature and ash emission begins.

[0012] S6: After the intelligent joint control stage of furnace temperature and ash emission ends, the peak power sprint stage begins.

[0013] S7: The waste heat recovery process is continuously executed throughout the entire process cycle, from the start of the natural power ramp-up to the end of the intelligent joint control stage of furnace temperature and ash emission.

[0014] Preferably, obtaining the transformer's output current and output voltage values ​​and initiating natural power ramp-up includes:

[0015] Applying Ohm's law, the real-time resistance value of the Atchison furnace is calculated using the output voltage and output current values.

[0016] The real-time resistance value is compared with a preset resistance threshold. When the real-time resistance value is lower than the preset resistance threshold, the restrictions on the transformer's initial power setting and power rise slope are lifted.

[0017] Once the restriction is lifted, the maximum allowable output current value of the transformer is obtained. Based on the maximum allowable output current value and the real-time resistance value that is lower than the preset resistance threshold, the target power value is determined by the power calculation formula.

[0018] The power calculation formula is: ,in, For the target power value, The maximum allowable output current value, This is the real-time resistance value;

[0019] Output a power control command to the transformer corresponding to the target power value.

[0020] Preferably, the step of outputting a power control command to the transformer corresponding to the target power value includes:

[0021] Before the step of outputting a power control command corresponding to the target power value to the transformer, a furnace loading process optimization step is performed, specifically: the raw material of the negative electrode material to be graphitized is separated into N batches of raw material with different particle size ranges through a screening device; the raw material batches with particle size ranges from large to small are sequentially filled in the direction from the bottom of the furnace to the top of the furnace to form a gradient distribution of materials in the furnace;

[0022] Before performing the furnace loading process optimization step, a parameter optimization step is performed to determine the initial settings for the process target temperature value and the process required duration.

[0023] Preferably, the step of performing a parameter optimization step before executing the furnace loading process optimization step to determine the initial set values ​​for the process target temperature value and the required process duration includes:

[0024] The parameter optimization steps include: obtaining the characteristic parameters of the current raw material batch; and updating the product resistivity based on the characteristic parameters and historical production data. Value and peak process temperature Reaction time Correlation model coefficients The association model is as follows: , The offset constant is used to minimize the product resistivity per unit product power consumption. With the optimization objective as the goal, based on power consumption data from historical production data, within the feasible range of process peak temperature and reaction time, iterative calculations are used to find the combination of process peak temperature and reaction time that minimizes the product resistivity value under unit product power consumption, resulting in recommended process peak temperature and recommended reaction time. The recommended process peak temperature is set as the process target temperature value for the subsequent furnace temperature closed-loop control stage, and the recommended reaction time is set as the process requirement duration for the furnace temperature closed-loop control stage.

[0025] Preferably, the step of entering the time-of-use electricity load transfer phase after the natural power ramp-up ends includes:

[0026] When the power control command causes the Atchison furnace to reach the preset power threshold and the furnace core temperature reaches the first preset temperature threshold, it is determined that the natural power ramp-up has been completed and the real-time time-of-use electricity price signal of the power grid is obtained.

[0027] If the real-time time-of-use electricity price signal indicates that the current time is a low electricity price period, then the time-of-use electricity price load transfer stage is entered; during the time-of-use electricity price load transfer stage, the power control target value is set to a predetermined proportion of the transformer's maximum allowable output power, and a power control command corresponding to the predetermined proportion is output to the transformer;

[0028] The power control command is executed, and the end time signal of the low electricity price period is continuously monitored, while the furnace core temperature is also monitored.

[0029] When the low electricity price period is detected to have ended, or the furnace core temperature reaches the second preset temperature threshold, the time-of-use electricity price load transfer phase ends.

[0030] Preferably, the step of entering the energy efficiency dynamic balance stage after the end of the time-of-use electricity price load transfer stage includes:

[0031] After the load transfer phase of the time-of-use electricity price ends, if the furnace core temperature reaches the third preset temperature threshold, the energy efficiency dynamic balance phase will be entered, and the real-time resistance value of the Atchison furnace will be obtained as the first feedback signal.

[0032] The measured values ​​of at least two temperature sensors arranged at different locations inside the furnace are acquired as a second feedback signal;

[0033] Calculate the arithmetic mean of the second feedback signal, and denot it as the average furnace temperature;

[0034] Calculate the standard deviation of the second feedback signal and denot it as the temperature standard deviation;

[0035] The temperature standard deviation is compared with a preset uniformity threshold: if the temperature standard deviation is less than or equal to the preset uniformity threshold, the thermal field is uniform; if the temperature standard deviation is greater than the preset uniformity threshold, the thermal field is non-uniform.

[0036] Based on the first feedback signal and the average furnace temperature, the energy efficiency calculation formula is used. Calculate current energy efficiency indicators ;in, For calibration coefficients, This is the real-time resistance value. Average furnace temperature;

[0037] The power control target value is dynamically adjusted based on the thermal field uniformity result and the current energy efficiency index: if the thermal field is not uniform, the power control target value is reduced; if the thermal field is uniform, the power control target value is increased with the goal of improving the current energy efficiency index.

[0038] Based on the adjusted power control target value, a new power control command is generated and output to the transformer;

[0039] The first feedback signal and the second feedback signal are continuously acquired, and the steps of calculating the current energy efficiency index, judging the uniformity of the thermal field, and adjusting the target value of power control are repeatedly executed until the temperature standard deviation obtained from the calculation for M consecutive times is lower than the preset uniformity threshold and the furnace core temperature reaches the fourth preset temperature threshold, at which point the energy efficiency dynamic balance stage ends; where M is a preset positive integer.

[0040] Preferably, the step of entering the furnace temperature closed-loop control stage after the energy efficiency dynamic balance stage ends includes:

[0041] After the energy efficiency dynamic balance stage ends, the furnace core temperature reaches the fourth preset temperature threshold, and then enters the furnace temperature closed-loop control stage. The process target temperature value determined in the parameter optimization step is used as the set value, and the furnace core temperature measurement value is acquired in real time.

[0042] Calculate the difference between the measured furnace core temperature and the set value, and record it as the temperature deviation value;

[0043] Based on the temperature deviation value, the power regulation is calculated using a proportional-integral-derivative control algorithm, and a power control command is generated and output to the transformer based on the power regulation. The formula for calculating the power regulation is: ,in, For power regulation, This is the temperature deviation value. , and These are the preset proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the integral of the temperature deviation value from the start of control to the current time. To represent the rate of change of the temperature deviation value;

[0044] The power control target value is updated based on the power adjustment amount, and a corresponding power control command is generated and output to the transformer;

[0045] The process of repeatedly executing the steps of acquiring furnace core temperature measurement value, calculating temperature deviation value, calculating power adjustment amount, and generating and outputting power control command is formed into a closed-loop control loop.

[0046] The closed-loop control loop continues to operate until the furnace core temperature measurement value stabilizes within a preset tolerance range centered on the process target temperature value, and the cumulative stable operating time reaches the process requirement duration determined in the parameter optimization step, at which point the furnace temperature closed-loop control stage ends.

[0047] Preferably, the step of entering the intelligent joint control stage of furnace temperature and ash emission after the furnace temperature closed-loop control stage ends includes:

[0048] After the closed-loop control stage of furnace temperature is completed, the intelligent joint control stage of furnace temperature and ash emission is entered, and the correspondence between ash concentration and corresponding optimal temperature adjustment is analyzed based on historical production data.

[0049] The ash concentration range is divided into N concentration intervals. The optimal temperature rise gradient and the corresponding optimal exhaust valve opening are determined in each concentration interval to form a mapping table.

[0050] Real-time acquisition of furnace core temperature and ash concentration measurements;

[0051] The measured ash concentration value is matched with the concentration range in the mapping table to determine the current range;

[0052] Obtain the optimal temperature rise gradient corresponding to the current concentration range from the mapping table;

[0053] The target temperature value is the sum of the optimal temperature rise gradient and the basic process temperature set in the furnace temperature closed-loop control stage.

[0054] The target temperature is set as the set value, and the real-time core temperature measurement is used as the feedback value. The proportional-integral-derivative control algorithm is used to calculate the power regulation command and output the power regulation command to the transformer.

[0055] Obtain the optimal exhaust valve opening corresponding to the current concentration range from the mapping table;

[0056] Based on the optimal exhaust valve opening, and combined with the real-time ash concentration change rate, the exhaust valve opening is dynamically corrected to obtain the final exhaust valve opening. The dynamic correction formula is as follows: ,in, For the final exhaust valve opening, For correction factor, This represents the absolute value of the real-time ash concentration change rate. To achieve the optimal exhaust valve opening;

[0057] Output the valve control command corresponding to the final exhaust valve opening;

[0058] The entire process, from real-time acquisition of furnace core temperature and ash concentration measurements to output power adjustment commands and valve control commands, is continuously and repeatedly executed to form a closed-loop control.

[0059] When the ash concentration is below the purity threshold for P consecutive sampling cycles, the intelligent joint control phase of furnace temperature and ash emission ends.

[0060] Preferably, the step of entering the peak power sprint stage after the intelligent joint control stage of furnace temperature and ash emission ends includes:

[0061] After the intelligent control phase of furnace temperature and ash emission is completed, the total electrical energy input from the completion of natural power ramp-up to the intelligent control phase of furnace temperature and ash emission is calculated and recorded as the cumulative input electrical energy; the total electrical energy required by the process is obtained; the difference between the cumulative input electrical energy and the total electrical energy required by the process is calculated and recorded as the electrical energy gap; if the electrical energy gap is greater than zero, the peak power sprint phase is entered, otherwise the entire process is terminated.

[0062] During the peak power sprint phase, the power control target value is set to the maximum allowable output power value of the transformer, and a power control command corresponding to the power control target value is output to the transformer; the power control command is continuously executed, and the cumulative input energy is updated in real time; when the cumulative input energy reaches or exceeds the total energy required by the process, the peak power sprint phase ends, and the entire process is completed.

[0063] Preferably, the continuous execution of the waste heat recovery process throughout the entire process cycle, from the start of the natural power ramp-up to the end of the intelligent joint control phase of furnace temperature and ash emission, includes:

[0064] The temperature of the flue gas discharged from the top of the Atchison furnace is collected in real time and recorded as the flue gas temperature. When the flue gas temperature is higher than the first heat recovery threshold, the flue gas is guided to the feed preheating device to preheat the new batch of raw materials that have not been loaded into the furnace. The first heat recovery threshold is the minimum effective flue gas temperature set based on the heat exchange efficiency and economic benefits of the preheating device.

[0065] The surface radiation temperature of the Atchison furnace wall is collected in real time and recorded as the furnace wall temperature. When the furnace wall temperature is higher than the second heat recovery threshold, the auxiliary drying system is started to use the radiant heat of the furnace wall to dry the new batch of raw materials that have not been loaded into the furnace. The second heat recovery threshold is the minimum effective radiation temperature set according to the minimum heat flux density required for material drying.

[0066] Beneficial Effects: This invention significantly improves the overall energy efficiency and economy of the graphitization Atchison furnace by introducing multi-stage intelligent collaborative control. The invention dynamically adjusts the power input based on the real-time state of the furnace resistance and temperature field, overcoming the slow heating and energy waste caused by a fixed power curve; combined with a time-of-use pricing strategy, it actively transfers the load, reducing energy costs. The optimized gradient loading method and energy efficiency balance control jointly ensure thermal field uniformity, laying the foundation for consistent product quality. Process parameter optimization based on historical data modeling and high-precision closed-loop furnace temperature control achieves the desired resistivity product with the lowest unit power consumption. The ash emission control mechanism reduces heat and protective gas loss while efficiently purifying the ash, while the final peak power surge and full-process waste heat recovery further enhance energy saving and consumption reduction from the dimensions of energy replenishment and recycling, thus systematically realizing the efficient, stable, and low-cost operation of the graphitization preparation process for lithium battery anode materials. Attached Figure Description

[0067] Figure 1 This is a flowchart of the energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to the present invention.

[0068] Figure 2 This is a flowchart of the peak power sprint stage control of the present invention. Detailed Implementation

[0069] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the present invention, but are not intended to limit the present invention.

[0070] A method for energy-saving and consumption-reducing production of lithium battery anode materials using a graphitized Atchison furnace, such as... Figure 1 and Figure 2 As shown, it includes the following steps:

[0071] S1: Obtain the transformer's output current and output voltage values, and begin natural power ramp-up, including:

[0072] Applying Ohm's law, the real-time resistance value of the Atchison furnace is calculated using the output voltage and output current values.

[0073] The real-time resistance value is compared with a preset resistance threshold. When the real-time resistance value is lower than the preset resistance threshold, the restrictions on the transformer's initial power setting and power rise slope are lifted.

[0074] Once the restriction is lifted, the maximum allowable output current value of the transformer is obtained. Based on the maximum allowable output current value and the real-time resistance value that is lower than the preset resistance threshold, the target power value is determined by the power calculation formula.

[0075] The power calculation formula is: ,in, For the target power value, The maximum allowable output current value, This is the real-time resistance value;

[0076] Output a power control command to the transformer corresponding to the target power value.

[0077] It should be noted that this method begins with the real-time acquisition of the transformer's output current and voltage values, which are obtained directly through Hall effect sensors and voltage transformers installed on the transformer's secondary side. The core purpose of acquiring these electrical parameters is to accurately assess the real-time conductivity of the carbonaceous material in the Atchison furnace during the initial energization phase. This is the physical basis for subsequent intelligent power control. Traditional fixed power curve modes fail to respond to the dynamic changes in furnace resistance, resulting in insufficient energy utilization during the initial heating phase. Therefore, this step incorporates a natural power ramp-up stage, aiming to follow the natural decrease in material resistance as temperature rises, achieving safe and efficient initial heating.

[0078] Specifically, applying Ohm's law, the real-time operating resistance of the furnace body is calculated by dividing the collected output voltage value by the output current value. This resistance value directly reflects the overall conductivity of the furnace packing material, and its dynamic decrease indicates that the material is being gradually activated. The calculated real-time resistance value is compared with a safety threshold preset based on historical process data and material characteristics. The specific method for setting this threshold is as follows: based on historical production data from multiple batches, the inflection point at which the furnace body resistance decreases to a level that can safely handle large currents is statistically analyzed, and the lower limit of this statistical value is taken as the preset resistance threshold. When the real-time resistance is lower than this preset threshold, it indicates that a stable conductive path has been formed in the furnace, and the conservative restrictions on the transformer's initial output power and power increase slope are then lifted. Conversely, if the resistance is still higher than the threshold, the restrictions are maintained, and low-power, gentle heating continues to avoid localized overheating or electrical shocks caused by uneven current density.

[0079] The initial power setting refers to the low power applied during the initial power-on phase. Its specific setting is typically based on furnace type and raw material experience to ensure the gentleness and safety of initial heating. The power ramp rate refers to the allowable rate of power increase per unit time; controlling this ramp ensures a smooth heating process. After removing the restrictions, the maximum allowable output current of the transformer is read; this parameter is a hard constraint for the safe operation of the equipment. Combining this current limit with the currently reduced real-time resistance, a phased target power is calculated using a power calculation formula. The logic of this formula is: without exceeding the equipment's rated current, the maximum heat power that can be safely applied is calculated based on the material's current actual conductivity (resistance). If the real-time resistance decreases, it means the material has better conductivity, and the power that can be converted under the same current limit increases accordingly; conversely, the power target needs to be reduced. Finally, a control command corresponding to the target power is sent to the transformer, driving the Atchison furnace into a highly efficient heating zone optimized based on real-time physical conditions. This overcomes the shortcomings of traditional methods, such as slow start-up and low energy efficiency, laying the foundation for energy efficiency optimization throughout the entire graphitization preparation process.

[0080] The step of outputting a power control command to the transformer corresponding to the target power value includes:

[0081] Before the step of outputting a power control command corresponding to the target power value to the transformer, a furnace loading process optimization step is performed, specifically: the raw material of the negative electrode material to be graphitized is separated into N batches of raw material with different particle size ranges through a screening device; the raw material batches with particle size ranges from large to small are sequentially filled in the direction from the bottom of the furnace to the top of the furnace to form a gradient distribution of materials in the furnace;

[0082] Before performing the furnace loading process optimization step, a parameter optimization step is performed to determine the initial settings for the process target temperature value and the process required duration.

[0083] It should be noted that, addressing the shortcomings of existing furnace loading methods that rely on experience and easily lead to uneven distribution of heat field and current within the furnace, this invention first optimizes the material loading method before implementing the core dynamic power control. This step aims to create conditions for the subsequent efficient and uniform graphitization reaction from a physical structure perspective. Specifically, the petroleum coke or pitch coke anode material raw material to be processed needs to be separated into several batches according to particle size using a vibrating screen or drum screen. This pre-separation according to different particle size ranges is because the particle size of the material directly affects its bulk density and electrical contact characteristics. Traditional mixed loading methods result in significant differences in resistance and thermal conductivity in different parts due to the disordered particle size. Therefore, this method specifically stipulates that raw material batches should be filled sequentially from the bottom of the furnace to the top, from the largest particle size to the smallest. Placing large-diameter particles at the bottom of the furnace helps to form a stable support structure and a better foundation for conductive pathways; the gradient distribution of particle size decreasing from top to bottom can improve the uniformity and density of material accumulation throughout the furnace, thereby promoting the uniform transfer of current and heat flow during heating, reducing local overheating or reaction dead zones, and thus improving the overall efficiency of the graphitization process and product consistency.

[0084] Before performing the furnace loading process optimization step, a parameter optimization step is performed to determine the initial set values ​​for the process target temperature value and the required process duration, including:

[0085] The parameter optimization steps include: obtaining the characteristic parameters of the current raw material batch; and updating the product resistivity based on the characteristic parameters and historical production data. Value and peak process temperature Reaction time Correlation model coefficients The association model is as follows: , The offset constant is used to minimize the product resistivity per unit product power consumption. With the optimization objective as the goal, based on power consumption data from historical production data, within the feasible range of process peak temperature and reaction time, iterative calculations are used to find the combination of process peak temperature and reaction time that minimizes the product resistivity value under unit product power consumption, resulting in recommended process peak temperature and recommended reaction time. The recommended process peak temperature is set as the process target temperature value for the subsequent furnace temperature closed-loop control stage, and the recommended reaction time is set as the process requirement duration for the furnace temperature closed-loop control stage.

[0086] It should be noted that this invention performs a parameter optimization step before the furnace loading operation, aiming to establish scientific and personalized core process objectives for the graphitization process. This step addresses the problems of energy consumption and quality fluctuations caused by existing technologies relying on fixed or empirical parameters and ignoring raw material differences. Determining the initial setpoints for the target process temperature and the required process duration provides a clear benchmark for subsequent precise closed-loop furnace temperature control, guiding the graphitization reaction towards the preset optimal state.

[0087] First, characteristic parameters of the current raw material batch, such as ash content and particle size distribution, are obtained using an industrial analyzer and a laser particle size analyzer. Combined with historical production data recorded in a database, including different raw material characteristics, corresponding peak temperatures, holding times, and the resistivity and total power consumption of the final product, the calibration coefficient k in the correlation model is dynamically updated. This model reflects the mathematical relationship between the key indicator of graphitization—product resistivity—and the main process parameters: after determining the calibration coefficient k, increasing the peak temperature helps reduce product resistivity, while extending the reaction time also promotes the graphitization process, but both affect energy consumption. If a fixed k value from the historical model is used directly, the reaction behavior of the current raw material cannot be accurately predicted. The correlation model is as follows: Among them, the offset constant The core function is to ensure that the mathematical model has a reasonable mathematical definition at the start of the process (t=0), and to avoid the divergence of the logarithmic terms ln(0). From a physical perspective, it can be understood as an initial activation time offset required for the material to reach an effective reaction state before the graphitization reaction begins. The value of is usually determined by fitting historical data and is a small positive number (such as 1 second or several seconds) to ensure that the model is still meaningful at the beginning of the process.

[0088] After the model update, the goal is to minimize the comprehensive indicator of "product resistivity under unit product power consumption". Iterative calculations are performed based on historical power consumption data within the allowable temperature and time range of the process. By repeatedly simulating the dual impact of different temperature and time combinations on product resistivity and energy consumption, the unique optimal combination that minimizes this comprehensive indicator is sought. This optimal combination is the recommended process peak temperature and the recommended reaction time, which theoretically represents the process path with the highest energy utilization efficiency while ensuring the product achieves the expected conductivity. Setting this recommended temperature as the direct target of subsequent closed-loop control ensures that the heating process always targets the most economical reaction temperature point; setting the recommended reaction time as the holding time duration of the closed-loop control ensures sufficient reaction from a time perspective, thus systematically overcoming the shortcomings of traditional energy efficiency synergistic optimization methods.

[0089] S2: After the natural power ramp-up ends, the time-of-use electricity load transfer phase begins, including:

[0090] When the power control command causes the Atchison furnace to reach the preset power threshold and the furnace core temperature reaches the first preset temperature threshold, it is determined that the natural power ramp-up has been completed and the real-time time-of-use electricity price signal of the power grid is obtained.

[0091] If the real-time time-of-use electricity price signal indicates that the current time is a low electricity price period, then the time-of-use electricity price load transfer stage is entered; during the time-of-use electricity price load transfer stage, the power control target value is set to a predetermined proportion of the transformer's maximum allowable output power, and a power control command corresponding to the predetermined proportion is output to the transformer;

[0092] The power control command is executed, and the end time signal of the low electricity price period is continuously monitored, while the furnace core temperature is also monitored.

[0093] When the low electricity price period is detected to have ended, or the furnace core temperature reaches the second preset temperature threshold, the time-of-use electricity price load transfer phase ends.

[0094] It should be noted that the entry into the time-of-use (TOU) electricity load transfer phase stems from the fact that after the initial preheating of materials in graphitization production, the conditions for optimizing energy costs while maintaining process progress are met. Traditional rigid control strategies fail to link with the grid's TOU mechanism, resulting in an optimization gap in energy costs. This step, introduced after the natural power ramp-up, is precisely to proactively respond to electricity price fluctuations during the critical heating period. When the power control command causes the Atchison furnace to reach a preset power threshold, such as 70% of the transformer's rated power, and the furnace core temperature reaches a first preset temperature threshold, such as 800 degrees Celsius, as measured by thermocouples, the natural power ramp-up is considered complete. Both conditions must be met simultaneously to ensure that the material has established a stable and sufficiently active conductive heating state, rather than relying solely on a single electrical or temperature indicator for misjudgment. The specific method for setting the preset power threshold is as follows: based on the historical graphitization process curves of specific raw materials, analyze the typical power platform corresponding to the specific reaction stage of "completely stable conductive path, capable of bearing subsequent high power input" at a safe heating rate. The platform value is determined by statistically analyzing multiple batches of stable production data, and the threshold is finally determined by considering the current safety margin of the transformer and furnace. For example, for the raw materials in this embodiment, this threshold can be set to 70% of the transformer's rated power. The temperature thresholds involved in each stage of this invention (including the first, second, third, and fourth preset temperature thresholds) are all set according to the following general method: based on the historical graphitization process curves and material thermal analysis data of specific raw materials, key temperature nodes marking the transition of process stages are identified. These nodes usually correspond to abrupt changes in material conductivity, stable thermal field formation, or the characteristic temperatures of the start or end of specific chemical reactions. By statistically analyzing multiple batches of stable production data, the empirical range of these characteristic temperatures is determined, and then a specific threshold value is selected within this range according to the characteristics and process requirements of the current raw material batch.

[0095] Time-of-use (TOU) electricity price signals are obtained by connecting to the real-time electricity price data interface published by the power grid company. The purpose of this is to identify low-price periods, such as nighttime or holidays, and to proactively initiate load transfer during these periods. During low-price periods, the power control target value is set to a high predetermined percentage of the transformer's maximum allowable output power, such as 90%. This predetermined percentage aims to maximize the input power within the equipment's safety limits, utilizing the low electricity price to complete as much of the energy input required for the process as possible, thereby directly reducing electricity costs. Subsequently, corresponding power control commands are output to the transformer to increase heating intensity.

[0096] After executing the command, the system continuously monitors the end signal of the low-electricity-price period from the power grid and simultaneously monitors the furnace core temperature. This dual monitoring ensures the flexibility of the control strategy: once the low-electricity-price period ends, even if the process can still withstand high power, the phase must be terminated to avoid soaring electricity costs; or, if the furnace core temperature rises to a second preset temperature threshold, such as 1200 degrees Celsius, this indicates that the process has naturally progressed to a point where a change in control strategy is needed, and the load transfer should also be terminated. Through the intelligent execution of this phase, this method embeds dynamic cost control capabilities into the graphitization preparation process.

[0097] S3: After the time-of-use electricity price load transfer phase ends, the energy efficiency dynamic balance phase begins, including:

[0098] After the load transfer phase of the time-of-use electricity price ends, if the furnace core temperature reaches the third preset temperature threshold, the energy efficiency dynamic balance phase will be entered, and the real-time resistance value of the Atchison furnace will be obtained as the first feedback signal.

[0099] The measured values ​​of at least two temperature sensors arranged at different locations inside the furnace are acquired as a second feedback signal;

[0100] Calculate the arithmetic mean of the second feedback signal, and denot it as the average furnace temperature;

[0101] Calculate the standard deviation of the second feedback signal and denot it as the temperature standard deviation;

[0102] The temperature standard deviation is compared with a preset uniformity threshold: if the temperature standard deviation is less than or equal to the preset uniformity threshold, the thermal field is uniform; if the temperature standard deviation is greater than the preset uniformity threshold, the thermal field is non-uniform.

[0103] Based on the first feedback signal and the average furnace temperature, the energy efficiency calculation formula is used. Calculate current energy efficiency indicators ;in, For calibration coefficients, This is the real-time resistance value. Average furnace temperature;

[0104] The power control target value is dynamically adjusted based on the thermal field uniformity result and the current energy efficiency index: if the thermal field is not uniform, the power control target value is reduced; if the thermal field is uniform, the power control target value is increased with the goal of improving the current energy efficiency index.

[0105] Based on the adjusted power control target value, a new power control command is generated and output to the transformer;

[0106] The first feedback signal and the second feedback signal are continuously acquired, and the steps of calculating the current energy efficiency index, judging the uniformity of the thermal field, and adjusting the target value of power control are repeatedly executed until the temperature standard deviation obtained from the calculation for M consecutive times is lower than the preset uniformity threshold and the furnace core temperature reaches the fourth preset temperature threshold, at which point the energy efficiency dynamic balance stage ends; where M is a preset positive integer.

[0107] It should be noted that the introduction of the dynamic energy efficiency balance stage aims to address the problems of high energy consumption and uneven reaction caused by the lack of coordinated consideration of thermal field state and energy conversion efficiency in existing technologies. This stage begins after the time-of-use electricity load transfer ends, at which point the furnace core temperature has risen to the third preset temperature threshold, such as 1500 degrees Celsius, marking the entry of the material into the medium-high temperature graphitization range requiring fine-tuning. First, real-time resistance values ​​are obtained through voltage and current sensors on the secondary side of the transformer, serving as the first feedback signal reflecting the overall conductivity characteristics. Simultaneously, measurements are collected from at least two temperature sensors located at different positions within the furnace (e.g., key positions on the top, bottom, left, and right), serving as the second feedback signal for assessing the thermal field distribution. A single temperature point cannot characterize the entire process; measurements at at least two points are fundamental for evaluating the uniformity of temperature distribution.

[0108] The arithmetic mean of these temperature measurements is calculated to obtain the average furnace temperature, which characterizes the overall thermal level within the furnace. The standard deviation of these temperature values ​​is then calculated, directly quantifying the dispersion of temperature at each point around the average, i.e., thermal field non-uniformity. This temperature standard deviation is compared to a preset uniformity threshold. If the standard deviation is less than or equal to the threshold, the heat distribution is uniform; otherwise, it is non-uniform. The specific method for determining the preset uniformity threshold is as follows: Select consecutive production batches from the historical production database that meet the product resistivity standard and have the best energy consumption performance; extract multi-point temperature standard deviation data for these batches before entering the constant temperature stage (corresponding to the dynamic energy efficiency balance stage); calculate the statistical upper limit of these standard deviations (e.g., take the 95th percentile value of all data arranged in ascending order); and set this statistical upper limit as the preset uniformity threshold. This method ensures that the thermal field is considered "uniform" only when the non-uniformity (standard deviation) of the furnace temperature distribution is lower than 95% of historically excellent production batches, thus providing a foundation for subsequent high-quality graphitization. Based on real-time resistance values ​​and average furnace temperature, the current energy efficiency index is calculated using an energy efficiency calculation formula. The energy efficiency calculation formula is as follows: ,in, This refers to the current energy efficiency index (dimensionless). These are dimensionless calibration coefficients calibrated using historical data. This represents the real-time resistance value (Ω). The average furnace temperature is (K). The physical background of this formula lies in constructing an empirical index for evaluating the instantaneous conversion efficiency of electrical energy: real-time resistance. Directly related to Joule thermal power ( This reflects the instantaneous conversion capability of electrical energy; average furnace temperature This represents the accumulated thermal energy state of the system. (Ratio) Therefore, it is related to the "instantaneous heat production potential corresponding to a unit of accumulated heat energy". Calibration coefficient Its purpose is to normalize this physical ratio into a comprehensive energy efficiency index that can be used for horizontal comparison and control. .

[0109] The power control target value is dynamically adjusted based on the thermal field uniformity results and the current energy efficiency index: if the thermal field is non-uniform, the power control target value is reduced; if the thermal field is uniform, the power control target value is increased to improve the current energy efficiency index. Based on the adjusted power control target value, a new power control command is generated and output to the transformer. This process continues to cycle until the temperature standard deviation calculated for M consecutive times is lower than the preset uniformity threshold and the furnace core temperature reaches the fourth preset temperature threshold, indicating that the thermal field has stabilized and the process is ready, thus ending this stage. The specific method for setting the number of consecutive times M is as follows: based on the statistical process control principle, analyze the minimum number of samples in historical data where the temperature standard deviation is continuously lower than the threshold when the thermal field reaches a stable state, and add 1-2 samples as a safety margin. Typically, M is between 5 and 10.

[0110] S4: After the energy efficiency dynamic balance stage ends, the furnace temperature closed-loop control stage begins, including:

[0111] After the energy efficiency dynamic balance stage ends, the furnace core temperature reaches the fourth preset temperature threshold, and then enters the furnace temperature closed-loop control stage. The process target temperature value determined in the parameter optimization step is used as the set value, and the furnace core temperature measurement value is acquired in real time.

[0112] Calculate the difference between the measured furnace core temperature and the set value, and record it as the temperature deviation value;

[0113] Based on the temperature deviation value, the power regulation is calculated using a proportional-integral-derivative control algorithm, and a power control command is generated and output to the transformer based on the power regulation. The formula for calculating the power regulation is: ,in, For power regulation, This is the temperature deviation value. , and These are the preset proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the integral of the temperature deviation value from the start of control to the current time. To represent the rate of change of the temperature deviation value;

[0114] The power control target value is updated based on the power adjustment amount, and a corresponding power control command is generated and output to the transformer;

[0115] The process of repeatedly executing the steps of acquiring furnace core temperature measurement value, calculating temperature deviation value, calculating power adjustment amount, and generating and outputting power control command is formed into a closed-loop control loop.

[0116] The closed-loop control loop continues to operate until the furnace core temperature measurement value stabilizes within a preset tolerance range centered on the process target temperature value, and the cumulative stable operating time reaches the process requirement duration determined in the parameter optimization step, at which point the furnace temperature closed-loop control stage ends.

[0117] It should be noted that the dynamic energy efficiency balance stage ensures uniform thermal field and efficient energy conversion, laying the foundation for entering the core graphitization reaction zone, which requires extremely high temperature precision. The furnace temperature closed-loop control stage is designed for this purpose, aiming to overcome the defects of temperature fluctuations and uneven product performance caused by traditional fixed power curves. When the furnace core temperature reaches the fourth preset temperature threshold, such as 2200 degrees Celsius, it marks that the material has officially entered the critical graphitization temperature zone that requires long-term precise temperature control.

[0118] The target process temperature value determined in the parameter optimization step is used as the setpoint for closed-loop control, and the furnace core temperature is measured in real time using thermocouples located deep within the furnace core. The difference between the measured value and this setpoint is calculated to obtain the temperature deviation value. This value directly quantifies the degree of deviation between the current actual temperature and the ideal reaction temperature, and is the core basis for closed-loop control. Based on this temperature deviation value, the required power adjustment is calculated using a proportional-integral-derivative (PID) control algorithm. The proportional coefficient in the PID control algorithm... Integral coefficient and differential coefficients The specific tuning method is as follows: adopt the engineering tuning method, for example, calculate the initial parameters using the Ziegler-Nichols formula through the step response curve of the furnace temperature, and then make fine adjustments on site according to the actual temperature fluctuations until the system responds quickly and the overshoot is small.

[0119] Subsequently, based on the calculated power adjustment, a corresponding power control command is generated and sent to the transformer. The command essentially adjusts the transformer output to a new power control target value. This process is executed cyclically at high frequency, forming a real-time closed-loop control loop: temperature measurement, deviation calculation, power adjustment, influencing furnace temperature, and re-measurement. This loop continues to operate until the furnace core temperature measurement is stably controlled within a preset tolerance range centered on the process target temperature setpoint, for example, ±5 degrees Celsius. This preset tolerance range is determined based on historical production data by analyzing the correlation between 'furnace temperature control accuracy' and 'final product resistivity compliance rate'. The principle is to ensure that, under the current tolerance level, the product resistivity can stably meet process requirements. Simultaneously, the cumulative stable operating time within this temperature range must reach the process requirement duration determined in the parameter optimization step. Both conditions must be met simultaneously to ensure that the graphitization reaction achieves both the required temperature accuracy and sufficient reaction time, thereby guaranteeing that the final negative electrode material has stable and excellent conductivity.

[0120] S5: After the furnace temperature closed-loop control stage ends, the intelligent joint control stage of furnace temperature and ash emission begins, including:

[0121] After the closed-loop control stage of furnace temperature is completed, the intelligent joint control stage of furnace temperature and ash emission is entered, and the correspondence between ash concentration and corresponding optimal temperature adjustment is analyzed based on historical production data.

[0122] The ash concentration range is divided into N concentration intervals. The optimal temperature rise gradient and the corresponding optimal exhaust valve opening are determined in each concentration interval to form a mapping table.

[0123] Real-time acquisition of furnace core temperature and ash concentration measurements;

[0124] The measured ash concentration value is matched with the concentration range in the mapping table to determine the current range;

[0125] Obtain the optimal temperature rise gradient corresponding to the current concentration range from the mapping table;

[0126] The target temperature value is the sum of the optimal temperature rise gradient and the basic process temperature set in the furnace temperature closed-loop control stage.

[0127] The target temperature is set as the set value, and the real-time core temperature measurement is used as the feedback value. The proportional-integral-derivative control algorithm is used to calculate the power regulation command and output the power regulation command to the transformer.

[0128] Obtain the optimal exhaust valve opening corresponding to the current concentration range from the mapping table;

[0129] Based on the optimal exhaust valve opening, and combined with the real-time ash concentration change rate, the exhaust valve opening is dynamically corrected to obtain the final exhaust valve opening. The dynamic correction formula is as follows: ,in, For the final exhaust valve opening, For correction factor, This represents the absolute value of the real-time ash concentration change rate. To achieve the optimal exhaust valve opening;

[0130] Output the valve control command corresponding to the final exhaust valve opening;

[0131] The entire process, from real-time acquisition of furnace core temperature and ash concentration measurements to output power adjustment commands and valve control commands, is continuously and repeatedly executed to form a closed-loop control.

[0132] When the ash concentration is below the purity threshold for P consecutive sampling cycles, the intelligent joint control phase of furnace temperature and ash emission ends.

[0133] It should be noted that after the closed-loop control stage of furnace temperature is completed, the main body of the material has completed the graphitization conversion, but the residual ash impurities need to be further purified and discharged at high temperatures. This intelligent joint control stage of furnace temperature and ash emission aims to solve the problem of traditional methods lacking fine control over the emission process and easily causing waste of heat and protective gas. First, based on the ash concentration, corresponding furnace temperature adjustment, and exhaust valve opening data recorded in the historical database, the optimal process parameters for promoting emission under different impurity concentrations are analyzed to obtain the corresponding relationship. For example, high ash concentration corresponds to a high temperature rise gradient and a large exhaust valve opening. The specific mapping table is constructed as follows: collect a large amount of historical production batches, under different ash concentration ranges, the temperature rise gradient and exhaust valve opening data that minimize the overall energy consumption (including electricity consumption and protective gas consumption) to achieve the predetermined product purity standard. Through data mining techniques (such as cluster analysis or regression analysis), the optimal parameter combination in each concentration range is determined to form a mapping table from ash concentration to the optimal temperature rise gradient and the optimal valve opening. These empirical relationships are quantified, the ash concentration range is divided into several continuous intervals, and the optimal temperature rise gradient and optimal exhaust valve opening are preset for each interval, thereby constructing a process parameter mapping table that can be quickly queried.

[0134] Real-time measurements of furnace core temperature and ash concentration are acquired via furnace core thermocouples and a flue gas analyzer, serving as dual feedback for closed-loop control. The real-time ash concentration is compared with the concentration range in a mapping table to determine the current control range and index the corresponding optimal temperature rise gradient. This optimal temperature rise gradient is added to the base process temperature set for the furnace temperature closed-loop control stage to obtain the dynamic target temperature value for this stage. Using this target temperature as the setpoint and the real-time furnace core temperature as feedback, a proportional-integral-derivative algorithm is employed to calculate and output power adjustment commands, driving the transformer to adjust its output power. This achieves precise tracking and control of the furnace temperature rise process, ensuring efficient ash removal.

[0135] Simultaneously, the baseline value of the optimal exhaust valve opening corresponding to the same concentration range is obtained from the mapping table. Considering the fluctuation of ash discharge rate, the absolute value of the real-time ash concentration change rate is introduced to dynamically correct the baseline opening. The dynamic correction formula is: ,in, For the final exhaust valve opening, To achieve the optimal exhaust valve opening... This represents the absolute value of the real-time ash concentration change rate. This is a correction factor. The correction factor... The specific method for determining it is as follows: by analyzing the proportional relationship between the rate of change of ash concentration and the additional opening required to maintain stable emissions in historical data, linear regression is used to obtain it; its dimension is [concentration]⁻¹·[time], which is used to normalize the rate of change of concentration into a dimensionless adjustment factor.

[0136] Output this final valve opening command. By continuously looping the above measurement, matching, calculation, and output process, a closed-loop control of temperature and emissions is formed until the flue gas analyzer detects that the ash concentration is lower than the purity threshold set according to the product purity requirements for P consecutive sampling cycles, indicating that impurities have been fully discharged and the stage ends. The specific value of the purity threshold is a process control limit predetermined to ensure product purity meets the standards, based on the correspondence between 'exhaust stage flue gas ash concentration' and 'final product ash content' in historical production data. The specific method for setting the number of consecutive sampling cycles P is as follows: it is determined based on the sampling interval of the flue gas analyzer and the required ash concentration stabilization time. For example, if the concentration is required to remain stable for at least 2 minutes with a sampling interval of 6 seconds, then P should be set to at least 20.

[0137] S6: After the intelligent joint control stage of furnace temperature and ash emission ends, the peak power sprint stage begins, including:

[0138] After the intelligent control phase of furnace temperature and ash emission is completed, the total electrical energy input from the completion of natural power ramp-up to the intelligent control phase of furnace temperature and ash emission is calculated and recorded as the cumulative input electrical energy; the total electrical energy required by the process is obtained; the difference between the cumulative input electrical energy and the total electrical energy required by the process is calculated and recorded as the electrical energy gap; if the electrical energy gap is greater than zero, the peak power sprint phase is entered, otherwise the entire process is terminated.

[0139] During the peak power sprint phase, the power control target value is set to the maximum allowable output power value of the transformer, and a power control command corresponding to the power control target value is output to the transformer; the power control command is continuously executed, and the cumulative input energy is updated in real time; when the cumulative input energy reaches or exceeds the total energy required by the process, the peak power sprint phase ends, and the entire process is completed.

[0140] It should be noted that, as Figure 2 As shown, the design of the peak power sprint phase aims to address the insufficient total energy input caused by the earlier time-of-use electricity pricing and energy efficiency optimization strategies, ensuring the complete completion of the graphitization reaction. This phase starts after the purification process is completed. First, it calculates the accumulated electrical energy consumed from the start-up natural power ramp-up to the current level; this accumulated input reflects the actual work done. Simultaneously, it obtains the total process energy required for this batch of production. This value is calculated based on the current raw material characteristics and furnace charge, using typical unit product power consumption data from historical databases of similar raw materials when successfully completing graphitization, combined with the total furnace charge for this batch. For example, if the historical database shows a typical power consumption of 500 kWh / ton for similar raw materials, and the furnace charge for this batch is 20 tons, then the total process energy requirement is calculated as: 500 kWh / ton × 20 tons = 10,000 kWh.

[0141] The energy gap is calculated by subtracting the cumulative input energy from the total energy required for the process. If the gap is greater than zero, it indicates that the energy conditions for a complete reaction have not yet been met. In this case, the peak power sprint phase must be initiated, prioritizing product quality even in the face of high electricity prices. Conversely, if the gap is zero or negative, it means that the energy input is sufficient, and the entire graphitization heat treatment process, including cooling, can be terminated directly.

[0142] During the sprint phase, the control system directly sets the power control target value to the transformer's maximum allowable output power and issues corresponding commands to the transformer, enabling the equipment to operate at its maximum capacity. Throughout this process, the full-power command is continuously executed, and energy consumption is simultaneously accumulated, with the cumulative input energy value updated in real time. Once the updated cumulative input energy reaches or exceeds the total energy required for the process, it signifies that the energy gap has been filled, the energy conditions for the graphitization reaction have been met, and the sprint phase ends, marking the completion of the main graphitization process centered on heating. This mechanism, through energy auditing and forced replenishment at the end of the process, reduces the risk of sacrificing product quality due to excessive energy saving.

[0143] S7: Throughout the entire process cycle from the start of the natural power ramp-up to the end of the intelligent joint control stage of furnace temperature and ash emission, the waste heat recovery process is continuously executed, including:

[0144] The temperature of the flue gas discharged from the top of the Atchison furnace is collected in real time and recorded as the flue gas temperature. When the flue gas temperature is higher than the first heat recovery threshold, the flue gas is guided to the feed preheating device to preheat the new batch of raw materials that have not been loaded into the furnace. The first heat recovery threshold is the minimum effective flue gas temperature set based on the heat exchange efficiency and economic benefits of the preheating device.

[0145] The surface radiation temperature of the Atchison furnace wall is collected in real time and recorded as the furnace wall temperature. When the furnace wall temperature is higher than the second heat recovery threshold, the auxiliary drying system is started to use the radiant heat of the furnace wall to dry the new batch of raw materials that have not been loaded into the furnace. The second heat recovery threshold is the minimum effective radiation temperature set according to the minimum heat flux density required for material drying.

[0146] It should be noted that, in order to overcome the drawback of a large amount of unutilized waste heat in traditional graphitization processes, this method continuously implements a waste heat recovery process throughout the entire heating and purification cycle to improve overall energy efficiency. Specifically, the temperature of the exhaust gas is collected in real time by thermocouples installed in the furnace top flue. When the temperature of this flue gas exceeds a first heat recovery threshold set based on the heat exchange efficiency and operating cost of the preheating device, for example, 350 degrees Celsius, this portion of high-temperature flue gas is automatically guided to the feed preheating device containing a new batch of raw materials that has not yet been fed into the furnace. This preheating device is typically a gas-solid heat exchanger that uses the sensible heat of the waste gas to preheat the cold raw materials, thereby reducing the initial energy consumption during subsequent production.

[0147] Simultaneously, the surface radiation temperature of the Atchison furnace wall is collected using an infrared thermometer or surface thermocouple. When the furnace wall temperature exceeds the second heat recovery threshold set based on the minimum heat flux density required for material drying, the auxiliary drying system is activated. This system typically consists of a heat-conducting cavity or radiation collector surrounding the furnace wall, which directs the previously lost furnace wall radiant heat to dry a new batch of raw materials not yet entering the furnace, removing moisture and further reducing the evaporation heat consumption of the main furnace.

[0148] The setting of the first and second heat recovery thresholds follows the dual principles of "technical feasibility" and "economic rationality," and is determined through the following two steps: **Determination of the lower limit of technical feasibility:** First, based on the design parameters and thermal performance curves of the preheating device (e.g., a gas-solid heat exchanger) or auxiliary drying system, determine the minimum inlet flue gas temperature or minimum received radiant heat flux density required for its startup and effective heat exchange. These are used as the lower limits of the two thresholds. For example, the preheating device requires a flue gas temperature of at least 300°C to start the fan and achieve effective heat exchange. **Verification of the lower limit of economic rationality:** Second, perform a simple operational economic calculation. Calculate the energy-saving benefits obtained from recovering this portion of waste heat (e.g., savings in electricity or fuel costs) and compare them with the increased energy consumption costs of operating the recovery system (e.g., fans, pumps). The minimum flue gas temperature or minimum furnace wall radiant temperature that allows the energy-saving benefits to exceed the system operating costs is determined as the lower limit of the economic value of the threshold. The final first and second heat recovery thresholds are the higher of the technical and economic lower limits, respectively. For example, if the technical lower limit of the preheating device is 300°C, but calculations show that the cost savings from heat recovery only cover the power consumption cost of the fan when the flue gas temperature reaches 350°C, then the first heat recovery threshold should be set at 350°C. This method ensures that waste heat recovery is technically effective and incurs no net operating cost.

[0149] This continuous waste heat recovery process transforms the originally discarded flue gas and radiant heat into effective pre-treated energy, realizing the cascade utilization of thermal energy across production batches.

[0150] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for energy-saving and consumption-reducing production of lithium battery anode materials using a graphitized Atchison furnace, characterized in that: Includes the following steps: S1: Obtain the output current and output voltage values ​​of the transformer and begin natural power ramp-up; S2: After the natural power ramp-up ends, the time-of-use electricity load transfer phase begins; S3: After the time-of-use electricity price load transfer phase ends, the energy efficiency dynamic balance phase begins; S4: After the energy efficiency dynamic balance stage ends, the furnace temperature closed-loop control stage begins. S5: After the furnace temperature closed-loop control stage ends, the intelligent joint control stage of furnace temperature and ash emission begins. S6: After the intelligent joint control stage of furnace temperature and ash emission ends, the peak power sprint stage begins. S7: The waste heat recovery process is continuously executed throughout the entire process cycle, from the start of the natural power ramp-up to the end of the intelligent joint control stage of furnace temperature and ash emission.

2. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The process of obtaining the transformer's output current and output voltage values ​​and initiating natural power ramp-up includes: Applying Ohm's law, the real-time resistance value of the Atchison furnace is calculated using the output voltage and output current values. The real-time resistance value is compared with a preset resistance threshold. When the real-time resistance value is lower than the preset resistance threshold, the restrictions on the transformer's initial power setting and power rise slope are lifted. Once the restriction is lifted, the maximum allowable output current value of the transformer is obtained. Based on the maximum allowable output current value and the real-time resistance value that is lower than the preset resistance threshold, the target power value is determined by the power calculation formula. The power calculation formula is: ,in, For the target power value, The maximum allowable output current value, This is the real-time resistance value; Output a power control command to the transformer corresponding to the target power value.

3. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 2, characterized in that, The step of outputting a power control command to the transformer corresponding to the target power value includes: Before the step of outputting a power control command corresponding to the target power value to the transformer, a furnace loading process optimization step is performed, specifically: the raw material of the negative electrode material to be graphitized is separated into N batches of raw material with different particle size ranges through a screening device; the raw material batches with particle size ranges from large to small are sequentially filled in the direction from the bottom of the furnace to the top of the furnace to form a gradient distribution of materials in the furnace; Before performing the furnace loading process optimization step, a parameter optimization step is performed to determine the initial settings for the process target temperature value and the process required duration.

4. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 3, characterized in that... Before performing the furnace loading process optimization step, a parameter optimization step is performed to determine the initial set values ​​for the process target temperature value and the required process duration, including: The parameter optimization steps include: obtaining the characteristic parameters of the current raw material batch; and updating the product resistivity based on the characteristic parameters and historical production data. Value and peak process temperature Reaction time Correlation model coefficients The association model is as follows: , The offset constant is used to minimize the product resistivity per unit product power consumption. With the optimization objective as the goal, based on power consumption data from historical production data, within the feasible range of process peak temperature and reaction time, iterative calculations are used to find the combination of process peak temperature and reaction time that minimizes the product resistivity value under unit product power consumption, resulting in recommended process peak temperature and recommended reaction time. The recommended process peak temperature is set as the process target temperature value for the subsequent furnace temperature closed-loop control stage, and the recommended reaction time is set as the process requirement duration for the furnace temperature closed-loop control stage.

5. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The step of entering the time-of-use electricity load transfer phase after the natural power ramp-up ends includes: When the power control command causes the Atchison furnace to reach the preset power threshold and the furnace core temperature reaches the first preset temperature threshold, it is determined that the natural power ramp-up has been completed and the real-time time-of-use electricity price signal of the power grid is obtained. If the real-time time-of-use electricity price signal indicates that the current time is a low electricity price period, then the time-of-use electricity price load transfer stage is entered; during the time-of-use electricity price load transfer stage, the power control target value is set to a predetermined proportion of the transformer's maximum allowable output power, and a power control command corresponding to the predetermined proportion is output to the transformer; The power control command is executed, and the end time signal of the low electricity price period is continuously monitored, while the furnace core temperature is also monitored. When the low electricity price period is detected to have ended, or the furnace core temperature reaches the second preset temperature threshold, the time-of-use electricity price load transfer phase ends.

6. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The step of entering the dynamic energy efficiency balance phase after the end of the time-of-use electricity price load transfer phase includes: After the load transfer phase of the time-of-use electricity price ends, if the furnace core temperature reaches the third preset temperature threshold, the energy efficiency dynamic balance phase will be entered, and the real-time resistance value of the Atchison furnace will be obtained as the first feedback signal. The measured values ​​of at least two temperature sensors arranged at different locations inside the furnace are acquired as a second feedback signal; Calculate the arithmetic mean of the second feedback signal, and denot it as the average furnace temperature; Calculate the standard deviation of the second feedback signal and denot it as the temperature standard deviation; The temperature standard deviation is compared with a preset uniformity threshold: if the temperature standard deviation is less than or equal to the preset uniformity threshold, the thermal field is uniform; if the temperature standard deviation is greater than the preset uniformity threshold, the thermal field is non-uniform. Based on the first feedback signal and the average furnace temperature, the energy efficiency calculation formula is used. Calculate current energy efficiency indicators ;in, For calibration coefficients, This is the real-time resistance value. Average furnace temperature; The power control target value is dynamically adjusted based on the thermal field uniformity result and the current energy efficiency index: if the thermal field is not uniform, the power control target value is reduced; if the thermal field is uniform, the power control target value is increased with the goal of improving the current energy efficiency index. Based on the adjusted power control target value, a new power control command is generated and output to the transformer; The first feedback signal and the second feedback signal are continuously acquired, and the steps of calculating the current energy efficiency index, judging the uniformity of the thermal field, and adjusting the target value of power control are repeatedly executed until the temperature standard deviation obtained from the calculation for M consecutive times is lower than the preset uniformity threshold and the furnace core temperature reaches the fourth preset temperature threshold, at which point the energy efficiency dynamic balance stage ends; where M is a preset positive integer.

7. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The process of entering the furnace temperature closed-loop control stage after the energy efficiency dynamic balance stage ends includes: After the energy efficiency dynamic balance stage ends, the furnace core temperature reaches the fourth preset temperature threshold, and then enters the furnace temperature closed-loop control stage. The process target temperature value determined in the parameter optimization step is used as the set value, and the furnace core temperature measurement value is acquired in real time. Calculate the difference between the measured furnace core temperature and the set value, and record it as the temperature deviation value; Based on the temperature deviation value, the power regulation is calculated using a proportional-integral-derivative control algorithm, and a power control command is generated and output to the transformer based on the power regulation. The formula for calculating the power regulation is: ,in, For power regulation, This is the temperature deviation value. , and These are the preset proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the integral of the temperature deviation value from the start of control to the current time. To represent the rate of change of the temperature deviation value; The power control target value is updated based on the power adjustment amount, and a corresponding power control command is generated and output to the transformer; The process of repeatedly executing the steps of acquiring furnace core temperature measurement value, calculating temperature deviation value, calculating power adjustment amount, and generating and outputting power control command is formed into a closed-loop control loop. The closed-loop control loop continues to operate until the furnace core temperature measurement value stabilizes within a preset tolerance range centered on the process target temperature value, and the cumulative stable operating time reaches the process requirement duration determined in the parameter optimization step, at which point the furnace temperature closed-loop control stage ends.

8. The energy-saving and consumption-reducing method for producing lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The process of entering the intelligent joint control stage of furnace temperature and ash emission after the furnace temperature closed-loop control stage ends includes: After the closed-loop control stage of furnace temperature is completed, the intelligent joint control stage of furnace temperature and ash emission is entered, and the correspondence between ash concentration and corresponding optimal temperature adjustment is analyzed based on historical production data. The ash concentration range is divided into N concentration intervals. The optimal temperature rise gradient and the corresponding optimal exhaust valve opening are determined in each concentration interval to form a mapping table. Real-time acquisition of furnace core temperature and ash concentration measurements; The measured ash concentration value is matched with the concentration range in the mapping table to determine the current range; Obtain the optimal temperature rise gradient corresponding to the current concentration range from the mapping table; The target temperature value is the sum of the optimal temperature rise gradient and the basic process temperature set in the furnace temperature closed-loop control stage. The target temperature is set as the set value, and the real-time core temperature measurement is used as the feedback value. The proportional-integral-derivative control algorithm is used to calculate the power regulation command and output the power regulation command to the transformer. Obtain the optimal exhaust valve opening corresponding to the current concentration range from the mapping table; Based on the optimal exhaust valve opening, and combined with the real-time ash concentration change rate, the exhaust valve opening is dynamically corrected to obtain the final exhaust valve opening. The dynamic correction formula is as follows: ,in, For the final exhaust valve opening, For correction factor, This represents the absolute value of the real-time ash concentration change rate. To achieve the optimal exhaust valve opening; Output the valve control command corresponding to the final exhaust valve opening; The entire process, from real-time acquisition of furnace core temperature and ash concentration measurements to output power adjustment commands and valve control commands, is continuously and repeatedly executed to form a closed-loop control. When the ash concentration is below the purity threshold for P consecutive sampling cycles, the intelligent joint control phase of furnace temperature and ash emission ends.

9. A method for energy-saving and consumption-reducing production of lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The process of entering the peak power sprint phase after the intelligent joint control phase of furnace temperature and ash emission ends includes: After the intelligent control phase of furnace temperature and ash emission is completed, the total electrical energy input from the completion of natural power ramp-up to the intelligent control phase of furnace temperature and ash emission is calculated and recorded as the cumulative input electrical energy; the total electrical energy required by the process is obtained; the difference between the cumulative input electrical energy and the total electrical energy required by the process is calculated and recorded as the electrical energy gap; if the electrical energy gap is greater than zero, the peak power sprint phase is entered, otherwise the entire process is terminated. During the peak power sprint phase, the power control target value is set to the maximum allowable output power value of the transformer, and a power control command corresponding to the power control target value is output to the transformer; the power control command is continuously executed, and the cumulative input energy is updated in real time; when the cumulative input energy reaches or exceeds the total energy required by the process, the peak power sprint phase ends, and the entire process is completed.

10. A method for energy-saving and consumption-reducing production of lithium battery anode materials using a graphitized Atchison furnace according to claim 1, characterized in that, The waste heat recovery process is continuously executed throughout the entire process cycle, from the start of the natural power ramp-up to the end of the intelligent joint control stage of furnace temperature and ash emission, including: The temperature of the flue gas discharged from the top of the Atchison furnace is collected in real time and recorded as the flue gas temperature. When the flue gas temperature is higher than the first heat recovery threshold, the flue gas is guided to the feed preheating device to preheat the new batch of raw materials that have not been loaded into the furnace. The first heat recovery threshold is the minimum effective flue gas temperature set based on the heat exchange efficiency and economic benefits of the preheating device. The surface radiation temperature of the Atchison furnace wall is collected in real time and recorded as the furnace wall temperature. When the furnace wall temperature is higher than the second heat recovery threshold, the auxiliary drying system is started to use the radiant heat of the furnace wall to dry the new batch of raw materials that have not been loaded into the furnace. The second heat recovery threshold is the minimum effective radiation temperature set according to the minimum heat flux density required for material drying.

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