Busbar configuration method for improving stability of magnetic fluid of aluminum electrolysis cell

Abstract

The application provides a bus configuration method for improving the stability of a magnetic fluid of an aluminum electrolysis cell, and relates to the technical field of aluminum electrolysis. First, the bus of the aluminum electrolysis cell is connected, and the network configuration of the cell surrounding cathode bus of the aluminum electrolysis cell is performed; second, the section and the trend of each group of cell surrounding cathode bus are adjusted, the section and the length of the cathode soft belt head of each group of cathode steel rod are adjusted, the layout and the configuration of the cell surrounding cathode bus connected with each group of stand column bus and short circuit bus are adjusted, and the current value of each group of cathode of the networked cell surrounding cathode bus of the aluminum electrolysis cell and the current value of each stand column bus of the next aluminum electrolysis cell are ensured to be the same as the theoretical set value; finally, the equivalent resistance method and the finite element method are combined to perform electric field calculation, the rationality of the current distribution of the aluminum electrolysis cell is verified, the production fluctuation caused by uneven current is reduced, and the stability and the efficiency of the overall aluminum electrolysis production process are improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum electrolysis technology, and in particular to a bus configuration method for improving the magnetohydrodynamic stability of aluminum electrolysis cells. Background Technology

[0002] In industrial production, electrolytic aluminum is produced using the molten salt electrolysis method. The raw materials required for production are alumina and fluoride salts, and the direct current (DC) power required for electrolysis is supplied by a rectifier. Under the influence of DC power, the molten alumina in the electrolyte undergoes a redox reaction with the carbon anode, producing liquid primary aluminum. The aluminum electrolytic cell, as the main equipment for producing electrolytic aluminum, primarily consists of anodes and cathodes made of carbon materials, and a steel structure. The magnetofluid in the molten zone of the aluminum electrolytic cell is either molten electrolyte or liquid aluminum. After participating in the chemical reaction within the electrolytic cell, the current is guided through cathode strips connected to the cathode steel rods to the cathode busbars surrounding the cell. Several sets of cathode strips on the power-input side are connected to a set of cathode busbars on the power-input side, and the current is then conducted to the column busbars of the next electrolytic cell.

[0003] In traditional aluminum electrolysis cell bus configurations, the power inlet and outlet busbars are often independent, lacking crimping or welding points, which can lead to uneven current distribution. Taking a 200kA electrolysis cell as an example, this cell has five sets of column busbars, each potentially carrying unequal currents, thus causing magnetohydrodynamic instability issues within the cell. The combined effect of horizontal current and vertical magnetic field in the molten aluminum can cause fluctuations at the electrolyte-aluminum interface, thereby affecting the current efficiency of aluminum electrolysis and increasing energy loss.

[0004] Fluctuations are inevitable during the production process of aluminum electrolytic cells, such as uncontrolled alumina concentration, unstable thermal balance, human error, or unforeseen factors. These fluctuations can all be attributed to electrical balance imbalances. These imbalances further lead to magnetohydrodynamic fluctuations, potentially triggering severe fluctuations such as anodic effects or large swaying of the molten aluminum. These fluctuations not only affect the production of the current cell but can also negatively impact adjacent electrolytic cells, causing increased noise, swaying, and energy consumption in the electrolysis series. Moreover, eliminating such severe fluctuations is more difficult and time-consuming than eliminating ordinary fluctuations, resulting in greater damage. Therefore, the problem of severe fluctuations in aluminum electrolytic cells affecting the production of adjacent cells urgently needs to be addressed and resolved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a bus configuration method to improve the magnetic fluid stability of aluminum electrolytic cells, aiming to reduce the impact of severe fluctuations such as anode effect or large swaying of aluminum liquid on the normal production of the electrolytic cell and its adjacent aluminum electrolytic cells.

[0006] To achieve the above objectives, the main technical solution adopted by the present invention is as follows:

[0007] A method for configuring a busbar to improve the magnetohydrodynamic stability of an aluminum electrolytic cell, specifically including the following steps:

[0008] Step 1: Set up several sets of cathode busbars around the cell on the power inlet side and power outlet side of the aluminum electrolysis cell. Connect a set of cathode busbars around the cell to several sets of cathode flexible strips to form a current conduction path. The column busbars and the short-circuit busbars are all connected through the cathode busbars around the cell.

[0009] Furthermore, the operating current of the aluminum electrolytic cell is 100–800 kA;

[0010] Step 2: Connect the cathode busbars around several groups of tanks on the power input side to each other using aluminum busbars, aluminum flexible strips or aluminum welding sheets to form a network. Then connect the cathode busbars around several groups of tanks on the power output side to each other using aluminum busbars, aluminum flexible strips or aluminum welding sheets to form another network.

[0011] Furthermore, the cross-section of the aluminum busbar, aluminum flexible strip, or aluminum welding sheet can be adjusted as needed, with an adjustment range of (30~550)mm×(30~550)mm;

[0012] Furthermore, the types of aluminum electrolytic cells include ordinary aluminum electrolytic cells, three-layer high-purity aluminum electrolytic cells, and any other molten salt electrolytic cells that use electrolysis to produce raw materials;

[0013] Furthermore, the number of cathode busbars around the tank on the power input side and power output side is one group or several groups;

[0014] Step 3: By adjusting the cross-section and orientation of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods, and the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars, ensure that the current value flowing out of the cathode busbars around each group of cells in the networked aluminum electrolysis cell is the same.

[0015] Step 4: By adjusting the cross-section and direction of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods are adjusted accordingly. At the same time, the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars are adjusted to ensure that the current value flowing into each column busbar of the next aluminum electrolysis cell is the same as the theoretical set value.

[0016] Step 5: Calculate the electric field using a combination of the equivalent resistance method and the finite element method to verify the rationality of the current distribution in the aluminum electrolysis cell. The electric field refers to the distribution of current and voltage. This specifically includes the following steps:

[0017] Step 5.1: Establish a bus current calculation model and calculate the current flowing through the bus system, anode guide rod and anode steel claw according to Kirchhoff's laws;

[0018] Step 5.2: Using the finite element method, iteratively solve for each point determined by coordinates x, y, and z in the current field of the anode, melt, and cathode to obtain the current distribution in the entire aluminum electrolysis cell. The melt is electrolyte and aluminum liquid. The conductivity differential equation of the conductive part in the aluminum electrolysis cell can be expressed as the Laplace equation.

[0019] Step 5.3: Solve the problem using a computer and repeatedly adjust the calculation model until the ideal current distribution of the aluminum electrolysis cell is obtained.

[0020] The present invention has the following beneficial effects and advantages:

[0021] 1. The networked cathode busbars around the tanks improve the interconnectivity of the busbar system;

[0022] 2. When severe fluctuations such as anode effect or large swing of aluminum liquid occur, the network configuration method of aluminum electrolysis cell bus in this invention can effectively conduct and dissipate the abnormal large current caused by severe fluctuations in the aluminum electrolysis cell, thereby significantly reducing the "infection" of the abnormal large current in the electrolysis series and eliminating the impact on the upstream electrolysis cells in adjacent areas. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing that the busbars around a 200kA electrolytic cell in an embodiment of the present invention have not yet been networked.

[0024] Figure 2 This is a schematic diagram of the busbar network around a 200kA electrolytic cell according to an embodiment of the present invention.

[0025] Among them, 1. First column busbar and first short-circuit busbars I to V; 2. First power-in side busbar I; 3. First power-in side busbar II; 4. First power-in side busbar III; 5. First power-in side busbar IV; 6. First power-in side busbar V; 7. First power-out side busbar I; 8. First power-out side busbar II; 9. First power-out side busbar III; 10. First power-out side busbar IV; 11. First power-out side busbar V; 1', the first 2', Second Power Inlet Busbar and Second Short-Circuit Busbar I to V; 3', Second Power Inlet Busbar II; 4', Second Power Inlet Busbar III; 5', Second Power Inlet Busbar IV; 6', Second Power Inlet Busbar V; 7', Second Power Outlet Busbar I; 8', Second Power Outlet Busbar II; 9', Second Power Outlet Busbar III; 10', Second Power Outlet Busbar IV; 11', Second Power Outlet Busbar V. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings.

[0027] The aluminum electrolytic cell busbar of the present invention is composed of an input busbar, an output busbar, a column busbar, and a short-circuit busbar.

[0028] This invention provides a bus configuration method for improving the magnetohydrodynamic stability of aluminum electrolytic cells, specifically including the following steps:

[0029] Step 1: Set up several sets of cathode busbars around the cell on the power inlet side and power outlet side of the aluminum electrolysis cell. Connect a set of cathode busbars around the cell to several sets of cathode flexible strips to form a current conduction path. The column busbars and the short-circuit busbars are all connected through the cathode busbars around the cell.

[0030] The operating current of the aluminum electrolysis cell is 100-800kA;

[0031] Step 2: Connect the cathode busbars around several groups of tanks on the power input side with aluminum busbars, aluminum flexible strips or aluminum welding sheets to form a network, so that the busbars around several groups of tanks on the power input side are no longer independent and current flows between them. Then connect the cathode busbars around several groups of tanks on the power output side with aluminum busbars, aluminum flexible strips or aluminum welding sheets to form another network, so that the busbars around several groups of tanks on the power input side are no longer independent and current flows between them.

[0032] The cross-section of the aluminum busbar, aluminum flexible strip, or aluminum welding sheet can be adjusted as needed, with an adjustment range of (30~550)mm×(30~550)mm.

[0033] The types of aluminum electrolytic cells include ordinary aluminum electrolytic cells, three-layer high-purity aluminum electrolytic cells, and any other molten salt electrolytic cells that use electrolysis to produce raw materials;

[0034] The number of cathode busbars around the tank on the power input side and power output side is one group or several groups;

[0035] Step 3: By adjusting the cross-section and orientation of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods, and the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars, ensure that the current value flowing out of the cathode busbars around each group of cells in the networked aluminum electrolysis cell is the same.

[0036] Essentially, this is achieved by adjusting the resistance of each branch, thereby adjusting the current flowing through each branch, and thus achieving a uniform current distribution.

[0037] Step 4: By adjusting the cross-section and direction of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods are adjusted accordingly. At the same time, the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars are adjusted to ensure that the current value flowing into each column busbar of the next aluminum electrolysis cell is the same as the theoretical set value.

[0038] Step 5: The current in the aluminum electrolysis cell is introduced from the anode, passes through the electrolyte and molten aluminum to the cathode carbon block, and is then discharged by the cathode steel rod. The electric field is the energy basis for the operation of the aluminum electrolysis cell and the source of the formation of other physical fields. Therefore, the quality of the current distribution in the aluminum electrolysis cell has a significant impact on aluminum electrolysis production.

[0039] The electric field was calculated using a combination of the equivalent resistance method and the finite element method to verify the rationality of the current distribution in the aluminum electrolysis cell. The electric field refers to the distribution of current and voltage. The specific steps include:

[0040] Step 5.1: Establish a bus current calculation model. Calculate the current flowing through the bus system, anode guide rod, and anode claw according to Kirchhoff's laws. The calculation formula is as follows:

[0041] ∑E=∑I·R (1)

[0042] Where E represents voltage V, I represents current A, and R represents resistance Ω;

[0043]

[0044] in, j Represents a node, I j This represents the current (A) at each node;

[0045] Step 5.2: Using the finite element method, iteratively solve for each point determined by coordinates x, y, and z within the current fields of the anode, melt, and cathode to obtain the current distribution throughout the entire aluminum electrolysis cell. The melt consists of electrolyte and molten aluminum. The conductivity differential equation for the conductive portion within the aluminum electrolysis cell can be expressed as the Laplace equation, and the calculation formula is as follows:

[0046]

[0047] ∑V=∑I·R (4)

[0048] Where, σ x σ represents the conductivity of a point determined by coordinates x, y, and z along the x-axis. y σ represents the conductivity of a point determined by coordinates x, y, and z along the y-axis. z V represents the conductivity of a point determined by coordinates x, y, and z along the z-axis, where x represents the x-axis coordinate of the point determined by coordinates x, y, and z in a spatial rectangular coordinate system, y represents the y-axis coordinate of the point determined by coordinates x, y, and z in a spatial rectangular coordinate system, z represents the z-axis coordinate of the point determined by coordinates x, y, and z in a spatial rectangular coordinate system, and V represents the scalar potential of the point determined by coordinates x, y, and z.

[0049] Step 5.3: Solve the problem using a computer and repeatedly adjust the calculation model until the ideal current distribution of the aluminum electrolysis cell is obtained.

[0050] Example:

[0051] Taking a 200kA electrolytic cell as an example, Figure 1 This is a schematic diagram showing that the busbars around the slot in an embodiment of the present invention have not yet been networked. Figure 1 In the first power input side busbar I2, first power input side busbar II3, first power input side busbar III4, first power input side busbar IV5, and first power input side busbar V6 are not connected to each other; first power output side busbar I7, first power output side busbar II8, first power output side busbar III9, first power output side busbar IV10, and first power output side busbar V11 are not connected to each other. Each group of power input side busbars and each group of power output side busbars are connected to the first column busbar and the first short-circuit busbar (1) of the next electrolytic cell, and then introduced into the anode busbar, and then into the anode group. The anode busbars are connected to each other by a balance busbar.

[0052] Figure 2 This is a schematic diagram of the bus network around the slot according to an embodiment of the present invention. Figure 2 In this configuration, the second power-in side busbars I2', II3', III4', IV5', and V6' are all interconnected, and the second power-in side busbars are connected by a single, continuous busbar; the second power-out side busbars I7', II8', III9', IV10', and V11' are also interconnected, compared to... Figure 1 The bus configuration, the cross-section and direction of each group of power-in and power-out buses, and the cross-section and length of the cathode soft strip of each group of cathode steel rod heads are all adjusted according to theoretical calculations.

[0053] As mentioned earlier, the cross-section and orientation of the busbars around each group of slots, as well as the cross-section and length of the cathode flexible strip of each group of cathode steel rod heads, need to be adjusted after the networked power input and output busbars are compared with the original configuration. Figure 1 and Figure 2 The busbar routing shows that the layout and routing of each group of power-in side buses have been adjusted. The current introduced into each column of the next electrolytic cell by the networked cathode buses around the cell is pre-configured based on magnetic field calculations. In other words, the networked busbars around the cell optimize the busbar structure of this electrolytic cell while ensuring the magnetohydrodynamic stability of the cell.

[0054] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for configuring a busbar to improve the magnetohydrodynamic stability of an aluminum electrolytic cell, characterized in that, Including Next steps: Step 1: Set up several sets of cathode busbars around the cell on the power inlet side and power outlet side of the aluminum electrolysis cell. Connect a set of cathode busbars around the cell to several sets of cathode flexible strips to form a current conduction path. The column busbars and the short-circuit busbars are all connected through the cathode busbars around the cell. Step 2: Connect the cathode busbars around several groups of tanks on the power input side to each other using aluminum busbars, aluminum flexible strips or aluminum welding sheets to form a network. Then connect the cathode busbars around several groups of tanks on the power output side to each other using aluminum busbars, aluminum flexible strips or aluminum welding sheets to form another network. Step 3: By adjusting the cross-section and orientation of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods, and the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars, ensure that the current value flowing out of the cathode busbars around each group of cells in the networked aluminum electrolysis cell is the same. Step 4: By adjusting the cross-section and direction of the cathode busbars around each group of cells, the cross-section and length of the cathode soft strip of each group of cathode steel rods are adjusted accordingly. At the same time, the layout and configuration of the cathode busbars around the cells connected to each group of column busbars and short-circuit busbars are adjusted to ensure that the current value flowing into each column busbar of the next aluminum electrolysis cell is the same as the theoretical set value. Step 5: Calculate the electric field using a combination of the equivalent resistance method and the finite element method to verify the rationality of the current distribution in the aluminum electrolysis cell. The electric field refers to the distribution of current and voltage. This specifically includes the following steps: Step 5.1: Establish a bus current calculation model and calculate the current flowing through the bus system, anode guide rod and anode steel claw according to Kirchhoff's laws; Step 5.2: Using the finite element method, iteratively solve for each point determined by coordinates x, y, z in the current field of the anode, melt, and cathode to obtain the current distribution in the entire aluminum electrolysis cell. The melt is electrolyte and molten aluminum. The conductivity differential equation of the conductive part in the aluminum electrolysis cell can be expressed as the Laplace equation. Step 5.3: Solve the problem using a computer and repeatedly adjust the calculation model until the ideal current distribution of the aluminum electrolysis cell is obtained.

2. The bus configuration method for improving the magnetohydrodynamic stability of an aluminum electrolytic cell according to claim 1, characterized in that, In step 1, the operating current of the aluminum electrolysis cell is 100~800kA.

3. The bus configuration method for improving the magnetohydrodynamic stability of an aluminum electrolytic cell according to claim 1, characterized in that, In step 2, the cross-section of the aluminum busbar, aluminum flexible strip, or aluminum welding sheet can be adjusted as needed, with an adjustment range of (30~550) mm × (30~550) mm.

4. The bus configuration method for improving the magnetohydrodynamic stability of an aluminum electrolytic cell according to claim 1, characterized in that, In step 2, the types of aluminum electrolytic cells include ordinary aluminum electrolytic cells, three-layer high-purity aluminum electrolytic cells, and any other molten salt electrolytic cells that use electrolysis to produce raw materials.

5. The bus configuration method for improving the magnetohydrodynamic stability of an aluminum electrolytic cell according to claim 1, characterized in that, In step 2, the number of cathode busbars around the tank on the power input side and power output side is one group or several groups.

Images