Method and device for testing heat flow on the side wall of an electrolytic cell
By fixing a standard block to the sidewall of the electrolytic cell and establishing a heat flux relationship model using Fourier's law, the problem of measuring the heat flux density at high temperatures on the sidewall of the electrolytic cell was solved, achieving accurate measurement and cost reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGZHOU INST OF ENERGY CONVERSION CHINESE ACAD OF SCI
- Filing Date
- 2025-01-24
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies cannot effectively measure the heat flux density at high temperatures on the sidewalls of electrolytic cells, and high-temperature heat flux measuring instruments are expensive and have low utilization rates, resulting in resource waste.
A heat flux relationship model was established using Fourier's law. By fixing a standard block on the outer wall of the electrolytic cell and combining the temperature values of the inner and outer walls with the temperature value of the standard block, the heat flux density of the sidewall was calculated.
It enables accurate measurement of heat flux density on the sidewall of the electrolytic cell, reduces measurement costs, and avoids the waste of high-temperature heat flux measuring instruments.
Smart Images
Figure CN122448902A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat flux testing technology, and more specifically to a method and apparatus for testing the heat flux of the sidewall of an electrolytic cell. Background Technology
[0002] The sidewall temperature of an electrolytic cell can reach approximately 350°C, representing a high point of residual heat in the aluminum electrolysis process. Unlike residual heat in other areas, a certain thickness of the cell wall must be maintained inside the sidewall to ensure normal aluminum electrolysis production. Any change in sidewall heat flux will affect the thickness of the cell wall. If the sidewall heat flux increases, the cell wall will thicken, reducing the cell's volume and impacting production capacity; conversely, if the sidewall heat flux decreases, the cell wall will thin, potentially affecting production safety.
[0003] Currently, instruments for measuring heat flow typically have a temperature measurement range below 100°C and are mainly used for measuring soil heat flow. For applications with temperatures exceeding 100°C, the number of suitable instruments for measuring heat flow is limited, and they are expensive. While accurate measurement of the heat flow from waste heat in the electrolytic aluminum production process is necessary, this measurement is not required daily. Therefore, if an instrument purchased with an investment of tens of thousands of yuan is only used a few times, its low utilization rate will lead to a waste of resources. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a method and apparatus for testing the heat flux of the sidewall of an electrolytic cell, which can measure the heat flux density of the sidewall of the electrolytic cell and helps reduce the cost of heat flux measuring instruments for electrolytic aluminum production enterprises.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] In a first aspect, the present invention provides a method for testing the heat flow of the sidewall of an electrolytic cell, comprising the steps of:
[0007] The temperature values of the inner wall of the electrolytic cell and the temperature values of the outer wall are obtained according to the process requirements of the electrolytic cell.
[0008] Using Fourier's law, a first heat flow relationship model is established based on the temperature values of the inner wall and the outer wall;
[0009] A standard block is fixed on the outer wall of the electrolytic cell. The temperature value of the inner wall of the electrolytic cell is obtained according to the process requirements inside the electrolytic cell, and the temperature value of the contact surface between the standard block and the side wall and the temperature value of the standard block are measured.
[0010] Using Fourier's law, a second heat flow relationship model is established based on the temperature value of the inner wall of the electrolytic cell, the temperature value of the contact surface between the standard block and the side wall, and the temperature value of the standard block.
[0011] By combining the first heat flux relationship model and the second heat flux relationship model, the heat flux density of the sidewall of the electrolytic cell is obtained.
[0012] The method for testing the heat flow of the electrolytic cell sidewalls as described above further utilizes Fourier's law to establish a first heat flow relationship model based on the temperature values of the inner and outer sidewalls, specifically including:
[0013]
[0014] In the formula, q represents the heat flux density of the sidewall of the electrolytic cell; t1 and t2 represent the temperature values of the outer sidewall and the inner sidewall, respectively; δ represents the thickness of the sidewall of the electrolytic cell; and λ represents the thermal conductivity of the sidewall of the electrolytic cell.
[0015] The method for testing the heat flow on the sidewall of the electrolytic cell as described above further utilizes Fourier's law to establish a second heat flow relationship model based on the temperature values of the inner sidewall, the outer sidewall, and the standard block. Specifically, this includes:
[0016]
[0017]
[0018] In the formula, q' represents the heat flux density of the sidewall of the electrolytic cell after the standard block is fixed on the outer sidewall; t1 and t3 represent the temperature values of the outer sidewall and the inner sidewall after the standard block is fixed on the outer sidewall of the electrolytic cell, respectively; t'2 represents the temperature value of the contact surface between the standard block and the sidewall; λ1 represents the thermal conductivity of the standard block; and δ1 represents the thickness of the standard block.
[0019] Combining equations (2) and (3), we can obtain:
[0020]
[0021] From equation (4), it can be seen that temperature t1 is obtained through the production process, t'2 and t3 are obtained through measurement, and δ1 and λ1 are obtained by looking up the table. Therefore, equation (4) can be used to obtain... The value will Substituting the value into equation (1) and the measured data of t1 and t2, the heat flux density q of the sidewall of the electrolytic cell is obtained. In the measurement process, only the temperature value is read, the operation is simple, the result is reliable, and the overall cost is low.
[0022] Secondly, the present invention provides an apparatus for testing the heat flow of the sidewall of an electrolytic cell, comprising:
[0023] An electrolytic cell, wherein the sidewall of the electrolytic cell is provided with a plurality of parallel ribs;
[0024] A standard block is detachably fixed between two parallel ribs by a fixing assembly, the fixing assembly including: a plurality of internally threaded screw adjusting rods, each internally threaded screw adjusting rod including an adjusting rod, one end of which is threadedly connected to an adjusting nut, and the adjusting rod is provided with a plurality of positioning fastening nuts for fixing the standard block.
[0025] Compared with the prior art, the advantages of this invention are as follows:
[0026] 1. Because traditional methods cannot directly measure the uncertainty and variation of the thickness of the electrolytic cell walls, heat flux cannot be directly obtained from the measured temperature. This invention will... The value of is considered as a variable, and a heat flux relationship model is constructed using Fourier's law by fixing a standard block on the outer wall of the electrolytic cell. By combining this model, the heat flux density can be accurately calculated, effectively solving the problem of heat flux measurement.
[0027] 2. The standard block of the device is fixed between the parallel ribs on the side wall of the electrolytic cell by a detachable fixing component. The design of the adjusting rod, adjusting nut, and positioning fastening nut of the fixing component makes the positioning and installation of the standard block simple, and adapts to the working environment of the electrolytic cell with high magnetic field strength, small space, and no drilling and welding on the side wall.
[0028] 3. Considering the limited number and high cost of existing heat flow measurement instruments suitable for environments exceeding 100°C, and that measuring the residual heat flow of the sidewalls is not a daily necessity in the electrolytic aluminum production process, this invention can avoid the low utilization rate and resource waste caused by purchasing instruments costing tens of thousands of yuan, thus helping to reduce the cost expenditure of electrolytic aluminum production enterprises on heat flow measurement instruments. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 This is a schematic diagram of the electrolytic cell in an embodiment of the present invention;
[0031] Figure 2 This is a schematic diagram illustrating temperature measurement in an embodiment of the present invention;
[0032] Figure 3 This is a schematic diagram illustrating temperature measurement when a standard block is fixed to the outer wall of the electrolytic cell in an embodiment of the present invention.
[0033] Figure 4 This is a schematic diagram of the structure of an electrolytic cell in an embodiment of the present invention, wherein the sidewall is provided with several parallel ribs.
[0034] Figure 5 This is a schematic diagram of the structure of the fixing component in an embodiment of the present invention. Detailed Implementation
[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0036] Example:
[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments of this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0038] In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0039] Figure 1 This is a schematic diagram of the electrolytic cell in an embodiment of the present invention, as shown below. Figure 1As shown, the sidewall temperature of the electrolytic cell can reach approximately 350℃, which is the part with the highest waste heat temperature in the electrolytic aluminum production process. Unlike the waste heat in other parts, to ensure normal electrolytic aluminum production, the inner sidewall of the electrolytic cell must maintain a certain thickness of the cell wall. Any change in the heat flow of the sidewall will affect the thickness of the cell wall. If the heat flow of the sidewall increases, the cell wall will become thicker, thereby reducing the volume inside the cell and affecting production capacity; conversely, if the heat flow of the sidewall decreases, the cell wall will become thinner, which may affect the safety of production.
[0040] Currently, instruments for measuring heat flow typically have a temperature measurement range below 100°C and are mainly used for measuring soil heat flow. For applications with temperatures exceeding 100°C, the number of suitable instruments for measuring heat flow is limited, and they are expensive. While accurate measurement of the heat flow from waste heat in the electrolytic aluminum production process is necessary, this measurement is not required daily. Therefore, if an instrument purchased with an investment of tens of thousands of yuan is only used a few times, its low utilization rate will lead to a waste of resources.
[0041] This invention provides a method for testing the heat flow of the sidewall of an electrolytic cell, which may include the following steps: Step 1: Obtain the temperature value of the inner sidewall of the electrolytic cell and measure the temperature value of the outer sidewall according to the process requirements of the electrolytic cell, such as... Figure 2 As shown; Step 2, using Fourier's law, establish a first heat flow relationship model based on the temperature values of the inner and outer walls; Step 3, fix a standard block on the outer wall of the electrolytic cell, obtain the temperature value of the inner wall of the electrolytic cell according to the process requirements of the electrolytic cell, and measure the temperature value of the contact surface between the standard block and the side wall, as well as the temperature value of the standard block, as shown. Figure 3 As shown; Step 4, using Fourier's law, establish a second heat flux relationship model based on the temperature value of the inner sidewall of the electrolytic cell, the temperature value of the contact surface between the standard block and the sidewall, and the temperature value of the standard block; Step 5, combine the first heat flux relationship model and the second heat flux relationship model to obtain the heat flux density of the sidewall of the electrolytic cell.
[0042] Specifically, using Fourier's law, a first heat flow relationship model is established based on the temperature values of the inner and outer walls, including:
[0043]
[0044] In the formula, q represents the heat flux density of the sidewall of the electrolytic cell; t1 and t2 represent the temperature values of the outer sidewall and the inner sidewall, respectively; δ represents the thickness of the sidewall of the electrolytic cell; and λ represents the thermal conductivity of the sidewall of the electrolytic cell.
[0045] Specifically, using Fourier's law, a second heat flow relationship model is established based on the temperature values of the inner wall of the electrolytic cell, the outer wall, and the standard block. This model includes:
[0046]
[0047]
[0048] In the formula, q' represents the heat flux density of the sidewall of the electrolytic cell after the standard block is fixed on the outer sidewall; t1 and t3 represent the temperature values of the outer sidewall and the inner sidewall after the standard block is fixed on the outer sidewall of the electrolytic cell, respectively; t'2 represents the temperature value of the contact surface between the standard block and the sidewall; λ1 represents the thermal conductivity of the standard block; and δ1 represents the thickness of the standard block.
[0049] Combining equations (2) and (3), we can obtain:
[0050]
[0051] From equation (4), it can be seen that temperature t1 is obtained through the production process, t'2 and t3 are obtained through measurement, and δ1 and λ1 are obtained by looking up the table. Therefore, equation (4) can be used to obtain... The value will Substituting the value of t1 into equation (1) and the measured data of t1 and t2, we can obtain the heat flux density q of the sidewall of the electrolytic cell.
[0052] The working principle of the method for testing the heat flow on the sidewall of an electrolytic cell provided in this embodiment of the invention is described below:
[0053] ① Heat flow during normal operation.
[0054] Based on the process conditions, the inner wall temperature t1 remains constant and can be set as known. t2 can be directly measured using a thermocouple.
[0055] According to Fourier's law:
[0056]
[0057] The factors constituting thermal resistance include the tank walls, carbon bricks, and steel shell. The thermodynamic parameters such as the thickness and thermal conductivity of the carbon bricks and steel shell are readily available, and their corresponding temperatures can also be measured. However, the thickness of the tank walls in the electrolytic cell is an unknown quantity and varies with operating conditions. Therefore, in equation (1), neither the thickness nor the thermal conductivity is known. Equation (1) contains three unknowns. Since the thickness of the tank walls cannot be directly measured, the heat flow cannot be directly obtained from the measured temperature using the formula. This patent treats λ / δ in equation (1) as a single variable, thus reducing the number of unknowns in equation (1) from three to two.
[0058] ② Place a test standard block on the wall surface where the heat flux to be measured is to be measured.
[0059] There are three requirements for the standard block: First, the physical properties of the standard block must be known, including its geometric dimensions, specific heat, and thermal conductivity. Second, thermocouples must be placed on the standard block, and the heat flow value can be obtained through the data processing unit. The placement of the thermocouples should reflect the characteristics of the temperature field, be representative, and be easy to measure. Third, the standard block must have fixing components. Because the sidewalls of the electrolytic cell cannot be perforated, and welding on-site is difficult, specialized fixing components should be provided based on the characteristics of the site.
[0060] ③ Data testing and analysis methods.
[0061] By attaching the standard block to the sidewall using a specialized fixing component, the local thermal equilibrium of the sidewall is disrupted. This is because adding the standard temperature measuring block, regardless of its thermal resistance, introduces two additional thermal resistances: contact resistance and conduction resistance. With the ambient temperature and process temperature remaining constant, the overall temperature difference remains the same, but the heat flow through the temperature measuring block will change.
[0062] However, based on the process conditions, the inner wall temperature t1 remains constant and can be set as known. t2 and t3 can be directly measured by thermocouples.
[0063] According to Fourier's law:
[0064]
[0065] Under the new operating conditions, the heat flux will change. Given the original sidewall thermal resistance, the channel thickness will not change in the short term. Continuous measurements over two hours will not affect the channel thickness; therefore, λ / δ can be considered constant.
[0066] For the thermodynamic equations at the sidewall of the electrolytic cell:
[0067]
[0068] For the thermodynamic equation at the standard block:
[0069]
[0070] Based on the characteristics of series thermal resistance, the heat flow through the sidewall is the same as the heat flow through the standard block. Therefore, combining the two equations, we can obtain:
[0071]
[0072] From equation (4), it can be seen that temperature t1 is obtained through the production process, and t'2 and t3 are obtained through measurement. Furthermore, the parameters of the standard block, thickness δ1 and thermal conductivity λ1, can be obtained from a table. Therefore, equation (4) can be used to obtain... The value of t1. Substituting this value into equation (1), the actual heat flow value of the sidewall can be obtained based on the measured values of t1 and t2.
[0073] Figure 5 This is a schematic diagram of the fixing component in an embodiment of the present invention. Figure 5 As shown, an embodiment of the present invention provides an apparatus for testing the heat flow of the sidewall of an electrolytic cell, comprising:
[0074] An electrolytic cell, wherein the sidewall of the electrolytic cell is provided with a plurality of parallel ribs;
[0075] A standard block is detachably fixed between two parallel ribs by a fixing assembly, the fixing assembly including: a plurality of internally threaded screw adjusting rods, each internally threaded screw adjusting rod including an adjusting rod, one end of which is threadedly connected to an adjusting nut, and the adjusting rod is provided with a plurality of positioning fastening nuts for fixing the standard block.
[0076] The operation process of the device for testing the heat flow on the side wall of an electrolytic cell provided in this embodiment of the invention is described below:
[0077] ① Positioning of standard blocks.
[0078] Achieving heat flow measurement requires the standard block to be firmly attached to the sidewall. The electrolytic cell operates with a high magnetic field and limited space, making welding difficult. Drilling holes in the sidewall is not permitted due to process limitations. Therefore, a specialized fixing assembly is needed to position the standard block.
[0079] Figure 4 This is a schematic diagram of the structure of an electrolytic cell in an embodiment of the present invention, wherein the sidewall is provided with several parallel ribs; as shown. Figure 4 The image shows a heat dissipation window on the side wall of an electrolytic cell. It is typically about 600mm wide and 600mm high. To enhance heat dissipation, three fins are welded to the window wall. These fins are approximately 10mm high and 500mm long, with a thickness of about 10mm, providing sufficient strength.
[0080] The fixing assembly of the standard block consists of several internally threaded lead screws and adjusting rods. For example... Figure 5 As shown, each internal threaded lead screw adjusting rod consists of three main components: an adjusting nut, an adjusting rod, and a locking nut. When the adjusting nut is retracted, the entire adjusting rod can be inserted between the two ribs. By counter-rotating the adjusting nut, the adjusting rod can be extended, ensuring the internal threaded lead screw adjusting rod is securely supported between the two ribs. A standard block is fixed to the side wall surface at the locking nut in three dimensions: vertically through the lead screw, and horizontally and vertically.
[0081] ② Installation of thermocouples or temperature measuring devices.
[0082] Thermocouples or temperature measuring devices are the core tools for temperature measurement, and their measurement location and method are crucial. It is recommended to use a type K armored thermocouple, or a type K armored thermocouple with a matching measurement range and accuracy. Alternatively, an infrared temperature sensor can be used for temperature measurement.
[0083] Drill a measuring hole for interference fit on the standard block. Securely mount the thermocouple in the measuring hole. The temperature at that point can be obtained using an infrared temperature sensor through the measuring hole. During non-measuring periods, the measuring hole should be plugged with a standard piece; the standard piece is only removed for measurement. Alternatively, if using a thermocouple for temperature measurement, the front end of the measuring hole should be flattened using graphite powder and adhesive. If using an infrared temperature sensor, the standard piece is only removed for measurement.
[0084] ③ Data processing methods.
[0085] Set up three measurement points at each measurement height, take the average value, and round it to three decimal places. After inputting four temperature values, the heat flux density can be calculated.
[0086] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.
[0087] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0088] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0089] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for testing the heat flow on the sidewall of an electrolytic cell, characterized in that, Including the following steps: The temperature values of the inner wall of the electrolytic cell and the temperature values of the outer wall are obtained according to the process requirements of the electrolytic cell. Using Fourier's law, a first heat flow relationship model is established based on the temperature values of the inner wall and the outer wall. A standard block is fixed on the outer wall of the electrolytic cell. The temperature value of the inner wall of the electrolytic cell is obtained according to the process requirements inside the electrolytic cell, and the temperature value of the contact surface between the standard block and the side wall and the temperature value of the standard block are measured. Using Fourier's law, a second heat flow relationship model is established based on the temperature value of the inner wall of the electrolytic cell, the temperature value of the contact surface between the standard block and the side wall, and the temperature value of the standard block. By combining the first heat flux relationship model and the second heat flux relationship model, the heat flux density of the sidewall of the electrolytic cell is obtained.
2. The method for testing the heat flow of the sidewall of an electrolytic cell according to claim 1, characterized in that, Using Fourier's law, a first heat flow relationship model is established based on the temperature values of the inner wall and the outer wall, specifically including: In the formula, q represents the heat flux density of the sidewall of the electrolytic cell; t1 and t2 represent the temperature values of the outer sidewall and the inner sidewall, respectively; δ represents the thickness of the sidewall of the electrolytic cell; and λ represents the thermal conductivity of the sidewall of the electrolytic cell.
3. The method for testing the heat flow of the sidewall of an electrolytic cell according to claim 1, characterized in that, Using Fourier's law, a second heat flow relationship model is established based on the temperature values of the inner wall of the electrolytic cell, the outer wall, and the standard block. Specifically, this model includes: In the formula, q' represents the heat flux density of the sidewall of the electrolytic cell after the standard block is fixed on the outer sidewall; t1 and t3 represent the temperature values of the outer sidewall and the inner sidewall after the standard block is fixed on the outer sidewall of the electrolytic cell, respectively; t'2 represents the temperature value of the contact surface between the standard block and the sidewall; λ1 represents the thermal conductivity of the standard block; and δ1 represents the thickness of the standard block. Combining equations (2) and (3), we can obtain: From equation (4), we can see that the temperature t1 is obtained through the process requirements in the electrolytic cell, the data of t'2 and t3 are obtained through measurement, and the data of δ1 and λ1 are obtained by looking up the table. Therefore, we can obtain the result through equation (4). The value will Substituting the value of t1 into equation (1) and the measured data of t1 and t2, we can obtain the heat flux density q of the sidewall of the electrolytic cell.
4. An apparatus for testing the heat flow on the sidewall of an electrolytic cell, characterized in that, The method applicable to the heat flow test of the sidewall of the electrolytic cell according to any one of claims 1 to 3 includes: An electrolytic cell, wherein the sidewall of the electrolytic cell is provided with a plurality of parallel ribs; A standard block is detachably fixed between two parallel ribs by a fixing assembly, the fixing assembly including: a plurality of internally threaded screw adjusting rods, each internally threaded screw adjusting rod including an adjusting rod, one end of which is threadedly connected to an adjusting nut, and the adjusting rod is provided with a plurality of positioning fastening nuts for fixing the standard block.