Method for controlling feed to an aluminium electrolysis cell

Abstract

The invention relates to the field of non-ferrous metallurgy, and more particularly to the electrolytic production of aluminium, and can be used in automatic raw material feed systems to reduce the risks of insufficient raw material being introduced into a melt as a result of the adhesion of cooled electrolyte to a crust breaker. Proposed is a method for controlling the feed to an aluminium electrolysis cell, involving an automatic raw material feed system capable of distributing the requisite amount of raw material for an individual electrolysis cell in a metered fashion, taking into account the actual state of said cell by continuously measuring the distribution of current across the anodes. The technical result of the invention is that of reducing the risks of insufficient raw material being introduced into the melt as a result of the adhesion of cooled electrolyte to a crust breaker, and ensuring more efficient distribution of the alumina feed to a cell, thereby permitting a reduction in production costs, with a reduction in net costs, by making it possible to avoid excess consumption of raw material and to increase the yield of primary aluminium accordingly.

Description

[0001] METHOD OF CONTROLLING THE POWER SUPPLY OF AN ALUMINUM ELECTROLYSER

[0002] Field of technology to which the invention relates

[0003] The invention relates to the field of non-ferrous metallurgy, namely, to the electrolytic production of aluminum, and can be used in automatic feed systems for raw materials (electrolyzer feeding) to reduce the risks of insufficient raw materials entering the melt, associated with the sticking of solidified electrolyte to the punch.

[0004] State of the art

[0005] Today, the main tasks of the world's leading companies in aluminum production are to increase the productivity of newly developed electrolyzers, as well as to modernize existing equipment taking into account and the possibility of reducing costs and minimizing losses. One of the areas in this aspect is the development of automatic power supply systems for electrolyzers, which allows for the dosed supply of the required amount of raw materials for a single electrolyzer, taking into account its current state, and at the same time allowing for the most predictable influence on its operation in the future, practically without human intervention.

[0006] The main elements of the electrolyzer power supply systems are: a raw material transport system, a dry air supply system, a controller and pneumatic distributor system, bins for the supplied raw material, dispensers and metal punches. Modern aluminum electrolyzers also have systems for continuous measurement of the current load on the anodes, allowing real-time monitoring of the current on each anode and the ability to regulate it.

[0007] The main tasks in managing the operation of electrolyzers in the aluminum industry are maintaining the material and thermal balances in a state in which the physical and chemical parameters allow for the most efficient and least costly production of a larger quantity of products.

[0008] Maintaining the thermal balance of the operating electrolyzer, in particular, occurs by regulating the optimal interpolar distance on the electrolyzer, which allows for minimizing heat loss, reducing raw material consumption by changing power supply modes, but at the same time allowing for the most efficient dissolution of additives and incoming raw materials in the available volume of cryolite-alumina melt.

[0009] In most companies in the global aluminum industry, the electrolyzer is fed with alumina by an automatic feed system consisting of a punch and a dispenser. After analyzing the state of the electrolyzer by automatically evaluating the electrical components of the electrolyzer (voltage, current), the trend of the amount of alumina in the electrolyzer is calculated. Various methods and formulas used can be reduced to the general rule that with sufficient saturation with alumina, the voltage in the electrolyzer begins to decrease due to the resistance in the interpolar space and with a lack of the required amount of raw materials, the voltage increases. An exception may be a condition in which the voltage in the electrolyzer can increase due to an excessive amount of alumina melted in the liquid phase of the cryolite-alumina melt. In this case, the resistance increases and, accordingly, the voltage increases.When the voltage increases, the automatic cell condition assessment system may incorrectly interpret the increase in voltage and try to reduce it by additionally feeding fresh alumina.

[0010] All of the above does not allow for the most objective assessment of the electrolyzer condition at any given time and leads to overconsumption of fresh alumina, which in turn increases production costs, increasing the cost of production. Also, with an incorrect assessment, situations may arise with the electrolyzer entering the "hot run" - a condition in which the electrolyzer temperature is above the optimal values ​​and it is necessary to carry out measures to bring the electrolyzer to the specified production parameters, which also increases electricity costs and reduces the amount of aluminum produced, increases the working time of the process personnel engaged in eliminating the consequences.

[0011] In general, the process of obtaining aluminum by electrolysis can be described as:

[0012] As is known, the main process at the cathode is the reduction of trivalent aluminum Al3+ + Зe = Al0. At the carbon anode, the discharge of oxygen-containing ions occurs with the formation of carbon oxides CO and CO2. The overall reaction occurring in the electrolyzer can be represented in the form of the following equation:

[0013] AI2O3 + xC = 2Al + (2x - 3) CO + (3 - x) CO2 Theoretically, electrolysis consumes alumina and carbon, as well as electricity for the decomposition of alumina and maintaining the operating temperature.

[0014] In fact, fluoride salts are also consumed (to compensate for the alkali in alumina, losses and impregnation of the lining).

[0015] The electrolysis process is continuous. Alumina is periodically loaded into the electrolyte, and recycled electrolyte, aluminum fluoride, and calcium fluoride are loaded to maintain the electrolyte level and composition.

[0016] The main raw material for obtaining aluminum is alumina; the quality of the produced aluminum and the reduction of production costs depend on the quantity, quality of alumina and the method of feeding it into the melt (electrolyzer feeding).

[0017] Calculation and control of power supply for electrolyzers of enterprises of the global aluminum industry is reflected in separate patents.

[0018] A known method of controlling alumina feed to an electrolyzer using point feeders (patent RU 2233914, C25C 3 / 20, published on 10.08.2004), where the electrolyzer voltage is measured to maintain the alumina concentration within specified limits, cycles are formed consisting of a sequence of the basic power supply mode, the insufficient power supply mode and the excess power supply mode of the electrolyzer. The resistance Rnc and its time derivative dRnc / dt are calculated based on the measurements of the electrolyzer voltage and the series current in all modes. In the insufficient power supply mode, they switch to excess power supply when the derivative dRnc / dt exceeds the specified values. The periods of automated alumina feed (hereinafter AAF) are set in the insufficient and excess power supply modes proportionally to the AAF setpoint. The anode frame is moved only in the basic power supply mode. The AAF setpoint is adjusted depending on the duration of the electrolyzer stay in the insufficient power supply mode.If the duration of insufficient power supply exceeds the set value, the APG setting is increased and vice versa. The duration of the excess power supply mode is set constant.

[0019] A method for controlling electrolyzers for obtaining aluminum and a device for implementing it are known (application RU 2000130463, C25C 3 / 20, published on 20.12.2002). Just as in the previous patent, the control of electrolyzers for obtaining aluminum consists of maintaining the temperature regime of the electrolyzer by regulating the interpolar distance and the concentration of alumina within specified limits by alternating the modes of excess and insufficient supply, including measuring the voltage on the electrolyzer and the series current, calculating the current value of the reduced voltage Unp and the rate of its change over time dUnp / dt, comparing the calculated values ​​with the specified ones and making decisions on regulating the interpolar distance and switching to the modes of excess or insufficient supply of alumina based on the results of the comparison.In this case, the transition from the insufficient power supply mode to the excess power supply mode is carried out when the rate of change of the reduced voltage over time reaches the value dUnp / dt > G1, the transition from the excess power supply mode to the insufficient power supply mode is carried out when the rate of change of the reduced voltage over time reaches the value dUnp / dt < G2, where Gl, G2 are the threshold values ​​of the rate of change of the reduced voltage, determined experimentally, the regulation of the interpolar distance is carried out at the moment of transition from the excess power supply mode to the insufficient power supply mode, provided that:.

[0020] / Unp-иО / > U, where U0 is the nominal value of the reduced voltage, U is the dead zone specified by technological requirements.

[0021] The control of the aluminum electrolysis process in this electrolyzer is carried out by selecting the optimal parameters of the thermal and electrical balances.

[0022] A method for controlling the technological process in an aluminum electrolyzer is known (application RU 97106113, C25C 3 / 20, published 10.10.1998), where a change in the electrolyzer power supply occurs after a preliminary calculation, similar to the previous ones. But the main difference is the difference in the method for determining the required amount of alumina to eliminate a separate violation - the anode effect.

[0023] The disadvantages of the known solutions are that the calculations do not take into account the passivation of individual anodes and the circulation mass transfer in individual parts of the electrolyzer, and the entire volume of the supplied raw material is distributed uniformly. All analogues indicate various automatic systems and methods for calculating the feedstock into the electrolyzer, depending on various variables based on measuring the current and components of the operating voltage of the electrolyzer. These disadvantages do not allow for maximum optimization of the process, increased efficiency, reduced costs and optimal use of raw materials.

[0024] Disclosure of the essence of the invention

[0025] The objective of the invention is to develop a system for automatic feed of raw materials and their distribution to each individual point of the general feed system of the electrolyzer, based on additional calculation of hydrodynamic mixing of liquid cryolite-alumina melt. The technical result of the invention is to reduce the risks of insufficient entry of raw materials into the melt, associated with the sticking of solidified electrolyte to the punch, to increase the efficiency of distribution of alumina supply to the electrolyzer, allowing to reduce production costs by reducing the cost price, allowing to avoid overconsumption of raw materials and, accordingly, to increase the yield of primary aluminum.

[0026] The problem is solved, and the technical result is achieved due to the proposed method of controlling the power supply of an aluminum electrolyzer with automatic feedstock feed and continuous measurement of the current load on the anodes, according to which, for optimal saturation of the cryolite-alumina melt of the electrolyzer, based on the current load on the anodes of individual feed points, with automatic feedstock feed, the possibility of metered distribution of the required amount of raw materials for this electrolyzer is ensured, taking into account its state at the current moment. To control the power supply of the electrolyzer, the weight of the raw material dose of each dispenser is measured and, if necessary, adjusted, continuous measurement and calculation of the current load on all anodes is carried out.In this case, to determine the amount of required raw material required for supply through each individual feed point, the current load is calculated and analyzed on the anodes located as close as possible to the feed point, for which the electrolyzer is conditionally divided into separate blocks.

[0027] In the proposed method of controlling the power supply of an aluminum electrolyzer, including an automatic feedstock feed system, the new feature is that the system is designed with the possibility of dosed distribution of the required amount of raw materials for a separate electrolyzer, taking into account its current state with continuous measurement of the current distribution by the anodes, wherein: a) an analysis of the current load is carried out on the anodes located as close as possible to the feed point (alumina feed), for which any electrolyzer is divided into separate blocks, by calculating the current load of the anodes around the feed point with an analysis of the data continuously measured by the system; b) after calculating the current on the anodes of the feed points, the obtained values ​​​​for each feed point are recalculated to the rated current; c) the amount of alumina is calculated and distributed among individual feed points depending on the current state of the electrolyzer;d) the current need for raw materials at the time of calculation is calculated, for which the total dose of A1P is initially calculated, which can be supplied to the feed points with a single operation of all dispensers, then, according to the obtained results, the need for raw materials for each individual feed point of the electrolyzer is calculated. d) the dose of APG per unit of nominal current is recalculated and, according to the obtained results, the need for raw materials for each individual feed point of the electrolyzer is calculated;e) the results are summed up to obtain the total practically required amount of alumina for optimal saturation of the cryolite-alumina melt of the electrolyzer, based on the current load on the anodes of individual feed points, depending on the change in hydrodynamic mixing, position and height of the anode. g) calculation of the electrolyzer feed algorithm based on the obtained results of the current load and the amount of required raw material, which can be calculated as the operating factor of the mechanisms or as the basic setting of the APG mechanisms.

[0028] The invention is supplemented by special cases of its implementation. Thus, the number of blocks may be unlimited and depends on the number of power points of the electrolyzer.

[0029] According to stage a), the total current through the anodes around the APG point number 1 is calculated using the following formula:

[0030] S П=1А + Ш+ IC+ Ш, where IA, Ш, IC, Ш represent the current of the anodes located around the power point, see the example in Fig. 3.

[0031] Similarly, the calculation of currents on the anodes of all known points of the electrolyzer APG is carried out: S II; S 12; S 13;... S In, then the total current of the electrolyzer is calculated = S II + S 12 + S 13 + S In.

[0032] According to stage b), the obtained values ​​for each known power point at the rated current are calculated using the formula:

[0033] II priv = 1nom / Ьelectrolyzer * E II, where II priv is the current of the anodes located around the power point, recalculated to the nominal current, kA;

[0034] 1nom - nominal current of the electrolyzer, kA (represents the specified operating current of the electrolyzer);

[0035] Ьelectrolyzer - total current of the electrolyzer, kA (represents the actual measured current of the electrolyzer).

[0036] By checking the recalculated values, the sum of the currents at the known points of the APG should be equal to the value of the nominal operating current of the electrolyzer: 1nom = II priv + 12 priv + . . .In priv.

[0037] According to stage c), the total dose of the APG is calculated as follows: WcyMM = WI + W2 + W3 + . . . Wn, where WcyMM is the total weight of the raw material supplied by all punches during a single operation; Wl; W2; Wn is the weight of the raw material supplied by the dispenser of each individual feed point.

[0038] According to stage d), the APG dose per unit of nominal current is recalculated as follows:

[0039] WI = WcyMM / 1nom, KG

[0040] According to stage d), the raw material requirement for each individual feed point of the electrolyzer is calculated:

[0041] RW1 = II pref * WI, where: RW (Required weight) is the actual required weight of the raw material dose at a separate point, depending on the calculated reduced current of the anodes located around this feed point of the electrolyzer.

[0042] II priv - current of the anodes located around the power point, recalculated to the nominal current, kA;

[0043] WI – APG dose per unit of nominal current, kg / kA.

[0044] According to stage e), the results are summed: RW1 + RW2 + RW3 + RWn = WcyMM.

[0045] By checking the correctness of the calculation of the actual need for raw materials for known points A1P, the total weight of the dose A1P calculated earlier should be obtained.

[0046] According to stage g), the electrolyzer feed algorithm, calculated as the operating coefficient of the mechanisms, is produced by converting the previously obtained values ​​into the operating coefficient of the mechanisms, which allows the raw material to be supplied to individual feed points, changing the percentage ratio relative to the base, and the calculation is made using the formula:

[0047] 1 / (W * 100 / RW) * 1000, where: W is the weight of the raw material supplied by the feed point dispenser,

[0048] RW - the actual required weight of the raw material dose for a given point A1P,

[0049] 100 and 1000 are conversion factors.

[0050] According to stage g), the electrolyzer feed algorithm, calculated as the basic setting of the A1P mechanisms, is produced by calculating the response time of the electrolyzer feed system dispenser at a separate point, for the most efficient saturation of the cryolite-alumina melt at this point relative to the other points of this electrolyzer, and the calculation is made according to the formula:

[0051] W / (1priv * 0.336 * 1nom * 11 / 100 / 60 * 1.889 * 1), where: W is the weight of the raw material supplied by the feed point dispenser, kg; 1priv is the current of the anodes located around the feed point, recalculated to the nominal current, kA;

[0052] 0.336 - electrochemical equivalent of aluminum;

[0053] 1nom - rated current of the electrolyzer, kA;

[0054] 1} - current output, %;

[0055] Ц = ((1 / 0.336*24))* 100*Q / I)* 1000, where Q is the number of worked bath-days (days in operation during the period of calculation of the current efficiency);

[0056] 1.889 - theoretical calculation of alumina consumption for aluminum production;

[0057] 60 - time, min;

[0058] 100 and 1 are conversion factors.

[0059] Brief description of the drawings

[0060] Fig. 1 shows an example of a general diagram of the location of the power supply points of the electrolyzer.

[0061] Fig. 2 shows a schematic distribution of the electrolyzer into individual sections relative to the number of alumina feed points.

[0062] Fig. 3 shows an example of the distribution of anodes relative to one point A1P, for measuring the anode current and further calculations of the effective power supply at this point.

[0063] Fig. 4 shows a block diagram of the main process of calculating and controlling the power supply of the electrolyzer.

[0064] Implementation of the invention

[0065] A distinctive feature of the proposed method is that the electrolyzer and its power supply are considered as a set of separate "sections - blocks" requiring separate calculation of the feedstock supply for each individual "block" and not tied to each other, which allows this method to be used not only in the development of new high-power electrolyzers, but also to be used in the modernization of existing equipment, i.e. the method is universal. The proposed method can be used for absolutely any electrolyzers with baked anodes using an automatic feedstock supply system and a current load measurement system for each individual anode.

[0066] Currently, continuously measured values ​​of current and voltage of the electrolyzer are used to determine the state of the electrolyzer, based on which an algorithm is built for calculating the amount of alumina supplied in each period of time. Additionally, data on the temperature of the electrolyte and metal are used for the calculation, allowing for corrections that take into account the solubility of alumina in the liquid electrolyte melt.

[0067] The authors have carried out work on developing a system for automatic feeding of alumina into the electrolyzer, taking into account not only constants, but also variable factors affecting the operation of the electrolyzer as a whole. In particular, the effect of magnetohydrodynamics on the rate of dissolution and the amount of alumina entering the melt in various parts of the electrolyzer relative to the projection of each side of the electrolyzer was measured, work was carried out to determine the dependence of the rate of dissolution of alumina in the electrolyte depending on its volume and on the interpolar distance, respectively, the dependencies of various constants and variables among themselves were determined, such as:

[0068] - current strength;

[0069] - electrolyzer voltage;

[0070] - level and temperature of metal and electrolyte;

[0071] - diagram and position of the anode in the plane around the alumina feed point;

[0072] - current load on each anode and the influence of these values ​​on magnetohydrodynamics in a given location;

[0073] - the influence on the magnetic hydrodynamics of the mixing position of the busbar of an individual electrolyzer, the electrolyzers located before and after, as well as the adjacent row of electrolyzers connected in one series of housings;

[0074] - the influence of ferromagnetic conductors located near the electrolyzer and their influence on the movement of the mass of metal and electrolyte in the electrolyzer.

[0075] Currently, the distribution of the total amount of alumina fed to the electrolyzer depends on the currently measured reduced voltage (filtered voltage) and is distributed among the operating modes:

[0076] - NOMINAL - a mode in which the mechanisms are triggered in accordance with the calculated “APG Setting”.

[0077] - UNDERFILLING - a mode in which the amount of alumina supplied to the electrolyte is less than its consumption.

[0078] - OVERFILLING - a mode in which the amount of alumina supplied to the electrolyte is greater than its consumption.

[0079] - TEST - a mode in which the amount of alumina supplied to the electrolyte is significantly less than its consumption. - STARVATION - alumina is not supplied until the occurrence of the anode effect is predicted.

[0080] Depending on the specified conditions, switching between modes occurs, which causes an increase or decrease in the concentration of alumina in the cryolite-alumina melt, respectively, allows regulating the voltage of the electrolyzer, the most optimized amount of alumina supplied to the feed points. In this case, the required calculated amount of alumina is supplied uniformly to all feed points.

[0081] The theoretical consumption of alumina for the production of one ton of aluminum is calculated from the reaction 1 / 2 A1 + 3 / 2 C = Al + 3 / 2 CO2 and is 1888.9 kg / t. Based on practice, the consumption of alumina may vary depending on the type of electrolyzers, mechanical losses, transportation losses, etc.

[0082] In aluminum production, the concepts of “APG dose” and “APG setpoint” are used to calculate the coefficients of automatic feed equipment, allowing the calculation of the amount of alumina fed to the electrolyzer at a separate feed point in a given period of time.

[0083] To reveal the essence of the technical solution, some generally accepted concepts are given:

[0084] Electrolyzer current is the total current supplied to the electrolyzer.

[0085] Anode current strength is the current strength of an individual anode, depending on its condition and service life.

[0086] APG dose is the total mass of alumina supplied to the electrolyzer during a single feed of alumina from all point feeders of the electrolyzer.

[0087] APG setting - the time between the operation of individual breakers.

[0088] To control the proposed automatic raw material feed system (hereinafter referred to as ARF or APS), the following units of measurement are used:

[0089] Reduced current at APG points, in kA or multiple units.

[0090] The requirement is measured in kg, or in units that are multiples of kg, or in other units of weight measurement, or in conventional units.

[0091] Coefficient of mechanism operation, %.

[0092] Basic setting of the APG, in minutes.

[0093] Initially, to develop and describe the electrolyzer power supply control algorithm, work was carried out to measure the speed and circuits of metal and electrolyte circulation in electrolyzers with a current of 500 kA. In parallel, measurements of the current load were carried out on all anodes of the experimental electrolyzers. The dependence of the anode currents, the amount of alumina supplied by a separate power point, and the cryolite-alumina melt circulation circuit was obtained.

[0094] Most modern aluminum production technologies use several separate feed points into the aluminum electrolytic cell, located near a number of current-conducting anodes (an example is shown in Fig. 1).

[0095] The feed points in the middle part of the schematically depicted electrolyzer indicate the feed points for the raw material into the electrolyzer, located between the four anodes located around the given feed point.

[0096] To control the power supply of the electrolyzer according to the submitted application, it is necessary to first measure the weight of the dose of raw material supplied to each dispenser, and also to have the ability to continuously measure the current load on all anodes.

[0097] Initially, to determine the amount of required raw material required for feeding through each individual point, an analysis of the current load is carried out on the anodes located as close as possible to the feed point, for which any electrolyzer is divided into separate blocks. The number of blocks may be unlimited and depends on the number of feed points of the electrolyzer (see Fig. 2).

[0098] 1. The current load of the anodes around the power point is calculated using data continuously measured by the system.

[0099] The total current through the anodes around the APG point number 1 is calculated using the formula:

[0100] S П=1А + Ш+ IC+ Ш (example in Fig. 3)

[0101] Similarly, the calculation of currents on the anodes of all points of the electrolyzer APG is carried out: S 11; I2; I3;... S in

[0102] Next, the total current is calculated: I electrolyzer = S Il + I2 + I3 + In

[0103] After calculating the current at the anodes of the power supply points, the obtained values ​​for each power supply point are recalculated to the nominal current.

[0104] For example:

[0105] 11 priv = 1nom / I electrolyzer * S 11

[0106] By checking the recalculated values, the sum of the currents at the APG points should be equal to the value of the nominal operating current of the electrolyzer.

[0107] IHOM = 11 priv + 12 priv + . . .In priv

[0108] 2. The amount of alumina is calculated and distributed among individual points, depending on the current state of the electrolyzer.

[0109] Knowing the APG dose (the weight of the dose of the supplied raw material per one operation), based on the design features of the dispenser that supplies the raw material to the feed point and taking into account the current across the anodes of this APG point, the current need for raw materials at the time of the calculation is calculated. For this, the total APG dose that can be supplied to the feed points with a single operation of all dispensers is initially calculated:

[0110] WcyMM = Wl + W2 + W3 + . . . Wn, where: W sum is the total weight of the raw material supplied by all punches during a single operation. It can be specified in kg, or units multiple of kilogram, or other units of weight measurement, or accepted in conventional units.

[0111] Wl; W2; Wn - weight of raw material supplied by the dispenser of each individual feed point.

[0112] Then the APG dose per unit of nominal current is recalculated:

[0113] Wl = WcyMM / 1nom, KG

[0114] Based on the results obtained, the need for raw materials for each individual feed point of the electrolyzer is calculated:

[0115] RW1 = 11 priv * WI, where: RW (Required weight) - the actual required weight of the raw material dose of a separate point, depending on the calculated reduced current of the anodes located around this point of the electrolyzer supply. Can be specified in kg, or units multiple of kilogram, or other units of weight measurement, or accepted in conventional units

[0116] 11 priv - current of the anodes located around the power point, recalculated to the nominal current, kA;

[0117] WI – APG dose per unit of nominal current, kg / kA.

[0118] The results are summed up to obtain the total practical amount of alumina required for optimum saturation of the cryolite-alumina melt of the electrolyzer, based on the current load on the anodes of individual feed points, depending on the change in hydrodynamic mixing, position and height of the anode.

[0119] RW1 + RW2 + RW3 + RWn = WcyMM

[0120] By checking the correctness of the calculation of the actual need for raw materials at the APG points, the total weight of the APG dose calculated earlier should be obtained.

[0121] 3. Calculation of the electrolyzer power supply algorithm based on the obtained results of the current load and the amount of required raw materials.

[0122] Based on the objectives and technical capabilities, an algorithm for feeding the electrolyzer can be developed, calculated as the operating coefficient of the mechanisms, or as the basic setting of the APG mechanisms. For this, the previously calculated parameters are converted according to the following options:

[0123] Option 1. Coefficient of mechanism operation, %. The algorithm calculation for this option is performed by converting the previously obtained values ​​into a coefficient of mechanism operation, which allows feeding raw materials to individual feed points, changing the percentage ratio relative to the base one.

[0124] The calculation is made according to the formula:

[0125] 1 / (W * 100 / RW) * 1000, where: W is the weight of the raw material supplied by the feed point dispenser,

[0126] RW - the actual required weight of the raw material dose for a given point A1P,

[0127] 100 and 1000 are conversion factors.

[0128] Example 1

[0129] The weight of the A1P dose equal to 1.06, the calculated requirement of alumina at a given point equal to 0.952 kg, with a current load on the anodes around a given point of 99.33 kA and a current strength of 550 kA, the operating coefficient of the mechanisms at a given point will be equal to: 1 / (1.06*100 / 0.952)* 1000=111.3%.

[0130] That is, for the most effective saturation of the cryolite-alumina melt with alumina in a single time period with a measured current load on the anodes around this point, 111.3% of the one-time weight of the APG dose will be required.

[0131] Option 2. Basic setting A1P, min.

[0132] This algorithm calculates the response time of the electrolyzer feed system dispenser at a separate feed point for the most efficient saturation of the cryolite-alumina melt at this feed point relative to the other feed points of this electrolyzer. The calculated value is specified in minutes, but can be converted into any other value, multiple or comparable to the specified one.

[0133] Calculation formula:

[0134] W / (I pref * 0.336 * 1nom * I} / 100 / 60 *1.889 * 1), where: W is the weight of the raw material supplied by the feed point dispenser, kg;

[0135] 1priv - current of the anodes located around the power point, recalculated to the nominal current, kA;

[0136] 0.336 - electrochemical equivalent of aluminum;

[0137] 1nom - rated current of the electrolyzer, kA;

[0138] 1} - current output, %;

[0139] 1.889 - theoretical calculation of alumina consumption for aluminum production;

[0140] 60 - time;

[0141] 100 and 1 are conversion factors. For the most accurate calculation of the effective required operating parameters of aluminum electrolyzers according to the given control methods, it is necessary to use automatic measurement systems that allow obtaining information on the measured operating parameters of the electrolyzer as accurately as possible and with minimal discreteness in terms of measurement and information processing time.

[0142] In both cases, the calculation allows to adjust the distributed power supply of the electrolyzer APG based on the actual state of the electrolyzer in each individual period of time, taking into account the state of the anode array, the height and layout of the anodes, as well as taking into account the constantly changing magnetohydrodynamic flows of metal and cryolite-alumina melt. All this together allows to reduce production costs, reducing the cost price, avoiding overspending of raw materials and, accordingly, increasing the yield of primary aluminum while reducing losses.

Claims

CLAUSE OF THE INVENTION 1. A method for controlling the power supply of an aluminum electrolyzer with automatic feedstock feed and continuous measurement of the current load on the anodes, characterized in that for optimal saturation of the cryolite-alumina melt of the electrolyzer, based on the current load on the anodes of individual feed points, with automatic feedstock feed, the possibility of a dosed distribution of the required amount of raw material for a given electrolyzer is ensured taking into account its state at the current moment, to control the power supply to the electrolyzer, the weight of the raw material dose of each dispenser is measured and, if necessary, adjusted, continuous measurement and calculation of the current load on all anodes is carried out, while to determine the amount of the required raw material necessary for feeding through each individual feed point, the current load on the anodes located as close as possible to the feed point is calculated and analyzed, for which the electrolyzer is conditionally divided into separate blocks.

2. The method according to item 1, including the following stages: a) an analysis of the current load on the anodes located as close as possible to the feed point is carried out, for which the electrolyzer is conditionally divided into separate blocks, by calculating the current load of the anodes around the feed point with an analysis of the data continuously measured in the process; b) after calculating the current on the anodes of the feed points, the obtained values ​​for each feed point are recalculated to the nominal current; c) taking into account the dose of automatic alumina feed (A1P), based on the design features of the dispensers feeding the raw material, the amount of alumina and its distribution among individual feed points are calculated;d) calculate the current need for raw materials at the time of calculation, depending on the current state of the electrolyzer, for which the total dose of A1P is initially calculated, which can be supplied to the feed points with a single operation of all dispensers, then, according to the obtained results, the need for raw materials for each individual feed point of the electrolyzer is calculated; d) recalculate the dose of APG per unit of nominal current and, according to the obtained results, calculate the need for raw materials for each individual feed point of the electrolyzer; e) to check the correctness of the previous calculations, the results are summed up to obtain the total practically required amount of alumina for optimal saturation of the cryolite-alumina melt of the electrolyzer, based on the current load; by the anodes of individual feed points, depending on the change in hydrodynamic mixing, position and height of the anode. g) calculate the electrolyzer feed algorithm based on the obtained results of the current load and the amount of required raw material, which can be calculated as the operating coefficient of the mechanisms or as the basic setting of the APG mechanisms.

3. The method according to item 1 or item 2, characterized in that the number of conventional electrolyzer blocks is selected taking into account the number of electrolyzer feed points.

4. The method according to item 2, characterized in that, according to stage a), the total current through the anodes around the APG point of the conventional block of electrolyzer number 1 is calculated using the formula: S П=1А + Ш+ IC+ Ш, similarly, the calculation of currents on the anodes of all points of the APG of the electrolyzer S II; S 12; S 13;. . . S In is carried out, then the total current I of the electrolyzer is calculated = S II + S 12 + S 13 + S In, according to stage b), the obtained values for each point of supply for the nominal current are calculated using the formula: II priv = 1nom / I of the electrolyzer * 111, the recalculated values ​​are checked, as a result of which the sum of the currents at the points of the APG should be obtained, equal to the value of the nominal current of the electrolyzer: 1nom = II priv + 12 priv + . . .In priv, according to stage d), the total dose of the APG is calculated as follows: WcyMM = Wl + W2 + W3 + . . . Wn, where: W sum is the total weight of the raw material fed by all punches during a single operation; Wl; W2; Wn - the weight of the raw material supplied by the dispenser of each individual feed point, according to stage d), the APG dose per unit of nominal current is recalculated as follows: Wl = WcyMM / 1nom, KG, according to stage e) the raw material requirement for each individual feed point of the electrolyzer is calculated as follows: RW1 = 11 pref * WI, where: RW is the actual required weight of the raw material dose of a separate point, depending on the calculated reduced current of the anodes located around this point of the electrolyzer feed; 11 priv - current of anodes around the power point, kA; WI - APG dose per unit of nominal current, kg / kA, according to stage g) the results are summed up: RW1 + RW2 + RW3 + RWn = WcyMM, checking the correctness of the calculation of the actual need for raw materials at the APG points, the total weight of the APG dose calculated earlier should be obtained.

5. The method according to item 2, additionally including stage 3), according to which the electrolyzer feed algorithm can be calculated as the operating coefficient of the mechanisms, the calculation is performed by converting the previously obtained values into the operating coefficient of the mechanisms, which allows the raw material to be supplied to individual feed points, changing the percentage ratio relative to the base, the calculation is performed using the formula: 1 / (W * 100 / RW) * 1000, where: W is the weight of the raw material supplied by the feed point dispenser, RW - the actual required weight of the raw material dose for a given APG point, 100 and 1000 are conversion factors.

6. The method according to i. 2, additionally including stage i), according to which the electrolyzer feed algorithm can be calculated as the basic setting of the APG mechanisms, the calculation is performed by recalculating the response time of the electrolyzer feed system dispenser at a separate feed point, for the most efficient saturation of the cryolite-alumina melt at this point relative to the other points of this electrolyzer, the calculation is performed according to the formula: W / (1priv * 0.336 * 1nom * 11 / 100 / 60 * 1.889 * 1), where: W is the weight of the raw material supplied by the feed point dispenser, kg; 1priv - current of the anodes located around the power point, recalculated to the nominal current, kA; 0.336 - electrochemical equivalent of aluminum; 1nom - rated current of the electrolyzer, kA; 1} - current output, %; 1.889 - theoretical calculation of alumina consumption for aluminum production; 60 - time, min.; 100 and 1 are conversion factors. 17

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