Electrolytic tank voltage regulation and control method in electrolytic aluminum process

Abstract

The invention discloses a method for regulating and controlling the voltage of an electrolytic tank in the electrolytic aluminum process. The method comprises the following steps of S1, data acquisition; s2, calculating the real-time optimal power supply voltage of the electrolytic cell; and S3, executing control. The method has the advantages that the optimal value of the power supply voltage of the electrolytic cell is determined according to multiple factors and is combined with four factors including the real-time cell voltage, the electrolyte temperature, the aluminum oxide concentration and the current of the electrolytic cell, so that the optimal value of the power supply voltage in the method can change in real time along with the state of the electrolytic process instead of being fixed, and therefore, the optimal value of the power supply voltage in the electrolytic cell is greatly improved. The power supply voltage of the electrolytic cell can be regulated and controlled in time according to the real-time situation, the control timeliness is better, through the dynamic and accurate regulation and control method, on the premise that the aluminum product quality is guaranteed, the efficiency, quality and stability of electrolytic aluminum production can be improved, meanwhile, energy consumption and production cost are reduced, and the economic benefits are improved. Equipment faults and maintenance cost caused by current fluctuation are reduced, and the method has remarkable economic benefits and industrial application value.

Description

Technical Field

[0001] The present invention relates to the field of electrolytic aluminum, and specifically relates to a method for regulating the voltage of an electrolytic cell during the electrolytic aluminum process. Background Art

[0002] Electrolytic aluminum is a process of producing aluminum by electrolyzing molten alumina. An appropriate cell voltage is one of the key factors to maintain the continuous and stable progress of this electrolytic reaction. If the electrolytic cell voltage is too high, it will not only cause waste of electric energy, but also overheat the electrolytic cell, accelerate the consumption of anode carbon blocks, and increase production costs. If the electrolytic cell voltage is too low, it cannot provide enough energy to drive the decomposition reaction of alumina, resulting in the abnormal progress of the electrolytic reaction or an extremely low reaction rate, and aluminum cannot be effectively deposited on the cathode, affecting production efficiency. At the same time, the stability of the cell voltage also has an important impact on the quality of aluminum products. When the voltage fluctuates, the reduction rate of aluminum ions on the cathode will change, which may reduce the purity of the deposited aluminum. It can be seen that maintaining a relatively stable cell voltage can ensure a more stable aluminum production process, thereby ensuring the stability of product quality.

[0003] In the actual industrial electrolysis process, in order to ensure the efficient and stable progress of the electrolytic reaction, the supply voltage of the electrolytic cell is usually continuously adjusted to keep the cell voltage in a relatively stable state. However, conventional regulation methods often preset an optimal value of the cell voltage. By comparing the detected real-time cell voltage value with the preset optimal value of the cell voltage, it is judged whether the deviation value is within the allowable range. If so, no adjustment is made; if not, corresponding adjustments are made.

[0004] During the electrolytic aluminum process, many factors will affect the cell voltage. Using a single preset optimal value as the basis for regulating the cell voltage has the following problems during the actual operation of the electrolytic cell: 1. It does not consider various actual situations during the electrolysis process. For example, as the electrolytic reaction progresses, alumina is continuously consumed, the resistance of the electrolyte will increase, and the current will decrease when the resistance increases, resulting in a decrease in the aluminum production rate.

[0005] 2. A single voltage regulation method may make the electrolytic cell in an unstable working state. For example, when the cell voltage is too high, the oxidation reaction of the anode will intensify, resulting in an accelerated consumption rate of the anode carbon block, increasing the replacement frequency of the anode carbon block, and further affecting the stable operation of the electrolytic cell.

[0006] 3. When the deviation value exceeds the allowable range and then the supply voltage of the electrolytic cell is adjusted, there will be a situation where the instantaneous adjustment amplitude is relatively large, resulting in too fast a voltage adjustment rate, causing fluctuations in the electrolytic cell and affecting the stable operation of the electrolytic cell. Summary of the Invention

[0007] The object of the present invention is to provide a method for regulating the voltage of an electrolytic cell during the electrolytic aluminum process. By precisely and dynamically regulating the voltage of the electrolytic cell, the cell voltage is maintained within a reasonable and stable range, enabling the electrolytic cell to operate stably, reducing production costs, and improving production efficiency.

[0008] The present invention is implemented by the following technical solutions: A method for regulating the voltage of an electrolytic cell during the electrolytic aluminum process, comprising the following steps: S1. Data acquisition: Collect the real-time operation data of the electrolytic cell during the electrolysis process; S2. Calculate the real-time optimal supply voltage of the electrolytic cell: Use the adaptive regulation algorithm to calculate the real-time optimal supply voltage of the electrolytic cell based on the real-time operation data collected in the step S1. S3. Execute control: First, set the target supply voltage range; Secondly, determine whether the additional condition is satisfied. When the additional condition is satisfied, the voltage regulating device of the cell controller regulates the supply voltage of the electrolytic cell according to the calculated real-time optimal supply voltage; When the additional condition is not satisfied, the voltage regulating device of the cell controller adjusts it in the direction close to the target supply voltage range and recalculates the optimal supply voltage.

[0009] Further, in the step S1. Data acquisition, the real-time operation data includes the electrolytic cell voltage, the electrolyte temperature, the alumina concentration, and the electrolytic cell current.

[0010] Further, the electrolytic cell voltage is collected by a voltage transformer connected in parallel with the main circuit of the electrolytic cell; the electrolyte temperature is collected by a thermocouple installed on the electrolytic cell within the electrolyte height range; the alumina concentration is collected by an on-line alumina measuring device; the electrolytic cell current is collected by a high-precision current transformer connected in series with the main circuit of the electrolytic cell.

[0011] Further, a plurality of thermocouples are installed at different positions of the electrolytic cell within the electrolyte height range. After the abnormal data points are removed from the multiple data collected by the plurality of thermocouples through preprocessing, the average value is calculated, and the obtained average temperature is the electrolyte temperature.

[0012] Further, the multiple data collected by the plurality of thermocouples are preprocessed by a median filtering algorithm.

[0013] Further, in the step S2. Calculate the real-time optimal supply voltage of the electrolytic cell, the adaptive regulation algorithm is shown in formula (1): (1) In formula (1), is the real-time optimal supply voltage, is the proportionality coefficient, is the integral coefficient, is the differential coefficient; is the deviation between the set power supply voltage of the preset electrolytic cell and the comprehensive actual operating conditions of the electrolytic cell, which is determined by formula (2): (2) In formula (2), and and and are the deviation weight coefficients corresponding to the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current respectively; and and and are the deviations between the set power supply voltage of the preset electrolytic cell and the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current respectively, where: (3) In formula (3), is the set power supply voltage of the preset electrolytic cell, is the real-time cell voltage of the electrolytic cell; and and are the functional relationships between the electrolytic cell power supply voltage and the electrolyte temperature, alumina concentration, and electrolytic cell current respectively, where: (4) (5) (6) In formula (4), T is the real-time electrolyte temperature of the electrolytic cell; in formula (5), C is the real-time alumina concentration in the electrolytic cell; in formula (6), I is the real-time current value of the electrolytic cell.

[0014] Furthermore, in the step S3 of execution control, the additional condition is: determining whether the optimal power supply voltage calculated in the step S2 for the real-time electrolytic cell is within the preset target power supply voltage range.

[0015] Furthermore, the voltage regulation rate of the voltage regulation device of the cell controller is 0.1V / min.

[0016] Advantages of the present invention: 1. The optimal value of the electrolytic cell power supply voltage is determined based on multiple factors, combining four factors: the real-time cell voltage, the electrolyte temperature, the alumina concentration, and the electrolytic cell current. It can be seen that the optimal value of the power supply voltage in the present invention changes in real time with the state of the electrolysis process, rather than being fixed. Therefore, the power supply voltage of the electrolytic cell can be adjusted in a timely manner according to the real-time situation, and the timeliness of control is better. Through this dynamic and precise control method, on the premise of ensuring the quality of aluminum products, the production efficiency, quality, and stability of electrolytic aluminum can be improved, while reducing energy consumption and production costs, and reducing equipment failures and maintenance costs caused by current fluctuations, with significant economic benefits and industrial application value.

[0017] 2. An additional condition for whether to adjust according to the calculated electrolytic cell power supply voltage is added, that is, to judge whether the optimal power supply voltage is within the preset target voltage range. Only when the additional condition is met, the regulation is carried out according to the optimal power supply voltage, thus avoiding the situation where the deviation between the power supply voltage and the preset target voltage range becomes larger and larger, and further improving the stability of the operation of the electrolytic cell. Specific implementation mode

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Embodiment 1 A method for regulating the voltage of an electrolytic cell during the electrolytic aluminum process includes the following steps: S1. Data acquisition: Collect the real-time operation data of the electrolytic cell during the electrolysis process; the real-time operation data includes the electrolytic cell voltage, the electrolyte temperature, the alumina concentration, and the electrolytic cell current; among them, the electrolytic cell voltage is collected by a voltage transformer connected in parallel with the main circuit of the electrolytic cell; the alumina concentration is collected by an on-line alumina measuring device; the electrolytic cell current is collected by a high-precision current transformer connected in series with the main circuit of the electrolytic cell; the electrolyte temperature is obtained by installing multiple thermocouples at different positions of the electrolytic cell within the electrolyte height range, and the multiple data collected by the multiple thermocouples are preprocessed by a median filtering algorithm to remove abnormal data points and then averaged.

[0020] In the present invention, the horizontal distance between the position where the thermocouple is installed and the electrode is 6 cm - 14 cm. At the same time, if the thermocouple is too close to the surface of the electrolyte, since the surface will exchange heat with the air and is also affected by factors such as heat dissipation of the upper structure of the electrolytic cell, the temperature fluctuation is large, which will affect the accuracy of the data. If the thermocouple is too close to the bottom of the electrolytic cell, since there may be substances such as precipitation at the bottom affecting heat conduction, it will also affect the accuracy of the data. Therefore, in the present invention, the total height of the electrolyte is evenly divided into three spaces with equal heights from top to bottom, and the thermocouple is installed in the space at the middle height to improve the accuracy of the data.

[0021] S2. Calculate the real-time optimal power supply voltage of the electrolytic cell: Use the adaptive control algorithm to calculate the real-time optimal power supply voltage of the electrolytic cell from the real-time operation data collected in step S1. The adaptive control algorithm is shown in formula (1): (1) In formula (1), is the real-time optimal power supply voltage, is the proportionality coefficient, is the integral coefficient, is the differential coefficient. In the present invention, 、 、 take the values of 0.6, 1.2, and 0.075 respectively; is the deviation between the set power supply voltage of the preset electrolytic cell and the comprehensive actual operation situation of the electrolytic cell, which is determined by formula (2): (2) In formula (2), 、 、 、 are the deviation weight coefficients corresponding to the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current respectively, indicating the relative importance of each factor for the control of the cell voltage. In the present invention, 、 、 、 take the values of 0.5, 0.3, 0.15, and 0.05 respectively; 、 、 、 are the deviations between the set power supply voltage of the preset electrolytic cell and the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current respectively, where: (3) In formula (3), is the set power supply voltage of the preset electrolytic cell, which is 4.3V in the present invention; is the real-time cell voltage of the electrolytic cell; , , are respectively the functional relationships between the power supply voltage of the electrolytic cell and the electrolyte temperature, alumina concentration, and electrolytic cell current. Among them: (4) (5) (6) In formula (4), T is the real-time electrolyte temperature of the electrolytic cell; in formula (5), C is the real-time alumina concentration in the electrolytic cell; in formula (6), I is the real-time current value of the electrolytic cell.

[0022] S3. Execution control: First, set the target power supply voltage range: According to the requirements of the electrolytic aluminum production process, a target power supply voltage range of 4.2 - 6.0 V is preset. This preset target power supply voltage range is determined by comprehensively considering factors such as the production efficiency of aluminum, energy consumption, and the stability of the electrolytic cell.

[0023] Secondly, judge whether the additional condition holds. When the additional condition holds, the voltage regulating device of the cell controller regulates the power supply voltage of the electrolytic cell according to the calculated real-time optimal power supply voltage; When the additional condition does not hold, the voltage regulating device of the cell controller adjusts in the direction close to the target power supply voltage range and recalculates the optimal power supply voltage.

[0024] Among them, the additional condition is: Judge whether the real-time optimal power supply voltage of the electrolytic cell calculated in step S2 is within the preset target power supply voltage range.

[0025] In the present invention, the rate of voltage regulation of the voltage regulating device of the cell controller is 0.1 V / min to avoid large fluctuations in the cell voltage.

[0026] Table 1 - 3 shows the cell voltage recording situations after the enterprise uses the method of the present invention to regulate the power supply voltages of 3 electrolytic cells respectively. It can be seen from Table 1 - 3 that through the regulation method of the present invention, the cell voltage can be quickly adjusted to a stable operation state after the electrolytic cell is started, and the cell voltage can be maintained within a relatively stable and reasonable range without large fluctuations, improving the stability of the operation of the electrolytic cell.

[0027] Table 1 Cell voltage recording situation of a new type of electrolytic cell of an enterprise after using the method of the present invention to regulate the power supply voltage of the electrolytic cell

[0028] Table 2 Cell voltage recording situation of a 50% high graphite quality electrolytic cell of an enterprise after using the method of the present invention to regulate the power supply voltage of the electrolytic cell

[0029] Table 3 Voltage recording of a certain all-graphitized electrolytic cell of an enterprise after regulating the power supply voltage of the electrolytic cell by using the method of the present invention

[0030] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for regulating the voltage of an electrolytic cell during the electrolytic aluminum process, characterized in that, It includes the following steps: S1. Data acquisition: Collect the real-time operation data of the electrolytic cell during the electrolysis process; S2. Calculate the real-time optimal supply voltage of the electrolytic cell: Calculate the real-time optimal supply voltage of the electrolytic cell through an adaptive control algorithm using the real-time operation data collected in step S1; S3. Execute control: First, set the target supply voltage range; Secondly, determine whether the additional condition is satisfied. When the additional condition is satisfied, the voltage regulating device of the cell controller regulates the supply voltage of the electrolytic cell according to the calculated real-time optimal supply voltage; When the additional condition is not satisfied, the voltage regulating device of the cell controller adjusts it in the direction close to the target supply voltage range and recalculates the optimal supply voltage.

2. The method for regulating the electrolytic cell voltage during the electrolytic aluminum process according to claim 1, wherein, In step S1, the data acquisition, the real-time operation data includes the electrolytic cell voltage, the electrolyte temperature, the alumina concentration, and the electrolytic cell current.

3. The method for regulating the electrolytic cell voltage during the electrolytic aluminum process according to claim 2, wherein, The electrolytic cell voltage is collected by a voltage transformer connected in parallel with the main circuit of the electrolytic cell; the electrolyte temperature is collected by a thermocouple installed on the electrolytic cell within the electrolyte height range; the alumina concentration is collected by an on-line alumina measuring device; the electrolytic cell current is collected by a high-precision current transformer connected in series with the main circuit of the electrolytic cell.

4. The method for regulating the electrolytic cell voltage during the electrolytic aluminum process according to claim 3, characterized in that, A plurality of thermocouples are installed at different positions of the electrolytic cell within the electrolyte height range. After the abnormal data points are removed from the multiple data collected by the plurality of thermocouples through preprocessing, the average value obtained by averaging is the electrolyte temperature.

5. The method for regulating the electrolytic cell voltage during the electrolytic aluminum process according to claim 4, characterized in that, The multiple data collected by the plurality of thermocouples are preprocessed through a median filtering algorithm.

6. The method for regulating the electrolytic cell voltage in the electrolytic aluminum process according to claim 1, wherein, In step S2, the calculation of the real-time optimal supply voltage of the electrolytic cell, the adaptive control algorithm is as shown in formula (1): （1） In formula (1), is the real-time optimal power supply voltage, is the proportionality coefficient, is the integral coefficient, is the differential coefficient; is the deviation between the set power supply voltage of the preset electrolytic cell and the comprehensive actual operating conditions of the electrolytic cell, which is determined by formula (2): (2) In formula (2), , , , are the deviation weight coefficients corresponding to the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current, respectively; , , , are the deviations between the set supply voltage of the preset electrolytic cell and the electrolytic cell voltage, electrolyte temperature, alumina concentration, and electrolytic cell current, respectively, where: (3) In formula (3), is the set supply voltage of the preset electrolytic cell, is the real-time cell voltage of the electrolytic cell; , , are respectively the functional relationships between the supply voltage of the electrolytic cell and the electrolyte temperature, alumina concentration, and electrolytic cell current, where: (4) （5） （6） In formula (4), T is the real-time electrolyte temperature of the electrolytic cell; in formula (5), C is the real-time alumina concentration in the electrolytic cell; in formula (6), I is the real-time current value of the electrolytic cell.

7. A method for regulating the voltage of an electrolytic cell during aluminum electrolysis according to claim 1, characterized in that, In step S3, the execution of control, the additional condition is: Determine whether the real-time optimal supply voltage of the electrolytic cell calculated in step S2 is within the preset target supply voltage range.

8. A method for regulating the electrolytic cell voltage in the process of electrolytic aluminum according to claim 1, characterized in that, The rate of voltage adjustment of the voltage regulating device of the cell controller is 0.1 V / min.

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