Magnesium electrolysis heat exchanger protection device and heat exchanger

Abstract

The invention provides a magnesium electrolysis heat exchanger protection device and a heat exchanger, the protection device comprises an outer sleeve and a bottom blocking plate, and the protection device is used for improving the reliability of an air pipe of the heat exchanger; the outer sleeve is arranged on the outer side of the air pipe in a sleeving mode, and the welding portion of the air pipe and the heat exchange pipe is packaged in a space formed between the outer side of the air pipe and the inner side of the outer sleeve. The bottom blocking plate is connected to the bottom ends of the outer sleeve and the air pipe and used for sealing the bottom of the outer sleeve and the bottom of the air pipe. At least two independent cavities are formed in the air pipe, each cavity is connected with the air channel of at least one heat exchange pipe set, and isolation and parallel circulation of airflow paths are achieved. By arranging the protection device, the air pipe below the electrolyte level is structurally optimized and protected, so that the reliability of the heat exchanger is effectively improved, and the service life of the heat exchanger is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal smelting technology, and more specifically, to a protection device and heat exchanger for a magnesium electrolysis heat exchanger. Background Technology

[0002] In the entire process of sponge titanium production, the electrolysis section plays a crucial role in providing liquid magnesium as raw material for subsequent production. However, the electrolysis of magnesium must be carried out in a high-temperature molten state. When current passes through the electrolyte, it not only generates a large amount of Joule heat, but the electrolysis reaction itself also releases heat. If the heat cannot be dissipated in time, the temperature of the electrolytic cell will continue to rise, causing the electrolyte to volatilize or decompose, resulting in abnormal problems such as decreased current efficiency and increased energy consumption.

[0003] To maintain thermal balance, magnesium electrolysis production processes are typically equipped with heat exchange devices. By dynamically adjusting the heat, the electrolysis reaction is ensured to proceed efficiently and safely within the optimal temperature range. This not only helps improve product quality and equipment stability but also effectively reduces energy consumption, ensuring process continuity and economic efficiency.

[0004] Traditional magnesium electrolysis heat exchangers, such as Figure 1 The heat exchanger mainly consists of inlet / outlet ducts, heat exchange tubes, protective sleeves for the liquid level in the inlet / outlet ducts, bottom blocking plates, and lifting lugs. During operation, the heat exchanger is constantly immersed in a high-temperature molten electrolyte. The connection between the heat exchange tubes and the inlet / outlet ducts is prone to damage due to the erosion and corrosion caused by the circulating electrolyte. Once damage occurs, the high-temperature molten electrolyte may seep into the heat exchange tubes, causing pipe blockage, reducing the effective heat exchange area, and even leading to the complete failure of the heat exchanger, thus seriously affecting the normal operation of the system. As a result, the service life of traditional magnesium electrolysis heat exchangers is typically only 12 to 14 months.

[0005] Chinese patent CN215766595U discloses a heat exchanger for temperature regulation in the magnesium collecting zone of a magnesium electrolysis cell, including a U-shaped heat exchange tube, an inlet pipe, an inlet header, an outlet pipe, an outlet header, a support structure, and an insulation structure. The U-shaped heat exchange tubes are arranged in parallel, mixed configurations to increase the heat exchange area. Furthermore, the welded joints between the inlet and outlet headers and the heat exchange tubes are positioned above the molten magnesium layer, preventing direct contact between the welded joints and the molten magnesium electrolyte or the molten magnesium layer, thus improving the heat exchanger's service life. However, the excessively long U-shaped heat exchange tube structure significantly increases the heat exchanger's volume, weight, and manufacturing cost.

[0006] Therefore, in order to address the problem that the welded joints between the heat exchange tubes and the inlet / outlet air ducts of magnesium electrolysis heat exchangers are prone to damage, leading to a reduction in the heat exchange area or failure of the heat exchanger, a protection device and a heat exchanger for magnesium electrolysis heat exchangers are needed to meet the needs of actual production. Summary of the Invention

[0007] The purpose of this invention is to provide a protection device and a heat exchanger for a magnesium electrolysis heat exchanger. By setting up the protection device, the structure of the air duct below the electrolyte level is optimized and protected, thereby effectively improving the reliability and service life of the heat exchanger.

[0008] To achieve the above objectives, the present invention provides a protection device for a magnesium electrolysis heat exchanger and a heat exchanger. The technical solution of the present invention is implemented as follows:

[0009] A protection device for a magnesium electrolysis heat exchanger, the magnesium electrolysis heat exchanger including a duct and at least two sets of heat exchange tubes, the protection device including an outer sleeve and a bottom blocking plate, the protection device being used to improve the reliability of the heat exchanger duct; the outer sleeve is fitted over the outside of the duct, encapsulating the welded joint between the duct and the heat exchange tubes within the space formed between the outside of the duct and the inside of the outer sleeve; the bottom blocking plate is connected to the bottom of the outer sleeve and the duct, for sealing the bottom of the outer sleeve and the duct; at least two independent cavities are provided inside the duct, each cavity being connected to the air duct of at least one set of heat exchange tubes, realizing the isolation and parallel flow of airflow paths.

[0010] Furthermore, the gap between the duct and the outer casing is filled with castable refractory. Filling with castable refractory not only improves the overall sealing effect but also enhances the mechanical strength and high-temperature resistance of the structure.

[0011] Furthermore, a partition is installed inside the air duct, which divides the air duct into two independent cavities.

[0012] Furthermore, the lower half of the duct near the liquid surface is provided with a cut, which is opened along the axial symmetrical plane of the duct to enable the partition to be embedded and installed.

[0013] Furthermore, the length of the cut is equal to the length of the partition to form an independent cavity, thereby achieving isolation and parallel flow of airflow paths.

[0014] Furthermore, an inner sleeve is also provided inside the air duct so that the installation of the partition does not require cutting or modifying the original air duct.

[0015] Furthermore, according to the position of the heat exchange tube, a corresponding through hole is provided on the outer sleeve, through which the heat exchange tube passes and connects to the outer wall of the air duct, so as to achieve full coverage of the air duct.

[0016] Furthermore, the protective device also includes a protective sleeve located inside the outer sleeve and connected to the heat exchange tube and the air duct. The protective sleeve covers the welded area between the heat exchange tube and the air duct to achieve full coverage and protection of the welded area, preventing corrosion or damage to the welded area.

[0017] Furthermore, the protective device is installed at both the air inlet pipe and the air outlet pipe.

[0018] Furthermore, the protective devices are installed at both the air inlet and outlet pipes to ensure that all critical components of the heat exchanger are adequately protected, thereby improving the overall safety and reliability of the equipment.

[0019] A magnesium electrolysis heat exchanger, the heat exchanger including the aforementioned protective device.

[0020] Compared with existing technologies, the magnesium electrolysis heat exchanger protection device and heat exchanger of the present invention have the following advantages:

[0021] 1. This invention adopts a triple protection design of "combined isolation + reinforced protective sleeve + filling casting material", which effectively prevents the electrolyte from scouring and corroding the air duct of the heat exchanger, and can effectively extend the service life of the heat exchanger.

[0022] 2. This invention adds a baffle at the duct, dividing the heat exchanger into two parallel parts, left and right. When a heat exchange tube on one side is damaged, only the local heat exchange function on that side is affected, while the other side can still operate normally, thereby improving the overall reliability and fault tolerance of the heat exchanger. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a traditional magnesium electrolysis heat exchanger.

[0024] Figure 2 This is a schematic diagram of the heat exchanger protection device, duct cut section, and outer casing as described in Embodiment 1 of the present invention;

[0025] Figure 3 A cross-sectional view of the heat exchanger described in Embodiment 1 of the present invention. Figure 1 ;

[0026] Figure 4 This is a perspective view of the heat exchanger described in Embodiment 3 of the present invention;

[0027] Figure 5 This is a top view of the heat exchanger protection device according to Embodiment 2 of the present invention;

[0028] Figure 6 This is a top view of the heat exchanger described in Embodiment 1 of the present invention;

[0029] Figure 7 A cross-sectional view of the heat exchanger described in Embodiment 1 of the present invention. Figure 2 Diagram of protective cover.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Air duct; 2. Outer casing; 3. Partition plate; 4. Bottom blocking plate; 5. Heat exchange tube assembly; 6. Lifting lug; 7. Protective sleeve; 31. Kit 1; 32. Kit 2. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0033] Example 1

[0034] A protection device for a magnesium electrolysis heat exchanger is provided to enhance the reliability of the heat exchanger duct 1. This protection device is applicable to conventional magnesium electrolysis heat exchangers, including the duct 1, heat exchange tube assembly 5, and lifting lugs 6, such as... Figure 3 As shown. The air duct 1 includes an air inlet duct and an air outlet duct, and two sets of heat exchange tube groups 5 connect the air inlet duct and the air outlet duct. Each set of heat exchange tube groups 5 includes several heat exchange tubes. Air enters the heat exchanger from the air inlet duct, passes through the heat exchange tube channels, and carries the heat out from the air outlet duct. Lifting lugs 6 are installed on the outer wall of the air duct 1 for the installation and fixation of the heat exchanger. During the magnesium electrolysis production process, the electrolyte immerses the welded part between the heat exchange tube group 5 and the air duct 1.

[0035] The protective device includes an outer sleeve 2, a partition 3, and a bottom blocking plate 4.

[0036] The outer sleeve 2 is fitted over the outside of the duct 1 to enclose the welded joint between the heat exchanger tube and the duct 1 within the space formed between the duct 1 and the outer sleeve 2. Corresponding through holes are provided on the outer sleeve 2 according to the position of the heat exchanger tube, through which the heat exchanger tube passes and connects to the outer wall of the duct 1. Corresponding through grooves are provided on the outer sleeve 2 according to the position of the lifting lug 6, through which the lifting lug 6 passes and connects to the outer wall of the duct 1. This achieves complete coverage of the duct 1. Preferably, the outer sleeve 2 adopts a split structure for easy installation and disassembly. The length and inner and outer diameters of the outer sleeve 2 are determined according to the specific structural design of the heat exchanger duct 1 to ensure complete coverage of the welded area between the heat exchanger tube and the duct 1.

[0037] A cut is provided in the lower half of the duct 1 near the liquid surface, and the cut is made along the axial symmetrical plane of the duct 1. The width of the cut matches the thickness of the partition 3 to allow for the embedded installation of the partition 3. The length of the cut is equal to the length of the partition 3 to form an independent cavity, achieving isolation and parallel flow of airflow paths. The length of the cut is greater than the depth to which the duct 1 is immersed in the liquid surface to ensure its effective range and to ensure that the submerged portion of the electrolyte is adequately protected.

[0038] like Figure 5 As shown, the end face of the cut is oblique to reduce friction and facilitate the insertion of the partition 3. At the same time, the cut is fixed and sealed by welding, thereby dividing the air duct 1 into two symmetrical parts, forming an internal channel with symmetrical structure and independent flow channels.

[0039] The air duct 1 is connected to the bottom blocking plate 4, and the structure is fixed and sealed by welding.

[0040] The partition 3 divides the internal space of the heat exchanger into at least two independent chambers, each chamber having at least one set of independent air ducts for the heat exchange tube group 5, achieving isolation and parallel flow of airflow paths. For example... Figure 6 As shown, the partition 3 symmetrically divides the air duct 1 into two independent chambers, allowing the two sets of heat exchange tube groups 5 to be connected in parallel. When one side of the heat exchange tube group 5 is damaged, only the local heat exchange function on that side is affected, while the other side can still operate normally, thereby improving the overall reliability and fault tolerance of the heat exchanger.

[0041] During installation, a slit of appropriate width is first machined into duct 1, and the cut end face is beveled. Then, the partition plate 3 is inserted into the slit, ensuring a tight fit between the partition plate 3 and duct 1. The joint between the partition plate 3 and duct 1 is welded using electric welding or surfacing, and the weld seam is ground smooth to ensure structural strength and sealing. This slit-insertion structure not only facilitates installation but also ensures that the interior of duct 1 is completely divided into two independent chambers. Even if one chamber fails and is filled with high-temperature molten electrolyte, leakage to the other chamber will not occur, thus improving the system's safety and reliability.

[0042] The bottom sealing plate 4 is connected to the bottom end of the outer casing 2 and the duct 1, and is used to seal the bottom of the outer casing 2 and the duct 1. The bottom sealing plate 4 is fitted and connected to the bottom end of the outer casing 2. Figure 2 As shown, the bottom blocking plate 4 is a circular plate with the same outer diameter as the outer casing 2. The outer casing 2 and the bottom blocking plate 4 enclose the lower end of the duct 1 within the internal space. The lower end of the duct 1 is completely enclosed by the outer casing 2 and the bottom blocking plate 4, effectively isolating the duct 1 from the influence of the high-temperature molten electrolyte, thereby improving the protection of the duct 1.

[0043] The protective device further includes a protective sleeve 7, which is disposed inside the outer sleeve 2 and located at the end of each heat exchange tube. The protective sleeve 7 is welded to the heat exchange tube and the air duct 1, and covers the welded area between the heat exchange tube and the air duct 1, providing protection for the weld joint. The shape of the protective sleeve 7 is designed according to the shape of the heat exchange tube and the air duct 1, fitting snugly to achieve complete coverage and protection of the welded area, preventing corrosion or damage. Preferably, the protective sleeve 7 is made of 316L stainless steel to enhance its durability and reliability, making it suitable for high-temperature and corrosive working environments.

[0044] The gap between the duct 1 and the outer casing 2 is filled with castable refractory to form a grouting layer, further enhancing the stability and sealing of the structure. Filling with castable refractory not only improves the overall sealing effect but also enhances the mechanical strength and high-temperature resistance of the structure. The grouting layer provides further protection for the welded joints between the duct 1 and the heat exchanger tube. The grouting layer also acts as an isolation layer from the external environment, while simultaneously improving the strength and durability of the welded joints.

[0045] Preferably, the castable is made of refractory material to effectively protect the welded joint between the duct 1 and the heat exchange tube from the effects of high temperature, corrosion, and other factors. The castable comprises refractory aggregate, powder and admixtures, binder, and additives. The refractory aggregate constitutes the material skeleton (70%–80%), determining the main high-temperature resistance and corrosion resistance; the powder and admixtures fill the gaps between the aggregates and optimize the matrix structure (10%–25%); the binder provides setting and hardening ability; and the additives adjust special functions such as explosion-proof and rheological properties.

[0046] Example 2

[0047] A protective device for a magnesium electrolysis heat exchanger, differing from Embodiment 1 in that the partition 3 in this embodiment does not require cutting or modifying the original duct 1. For example... Figure 5 As shown. The protective device includes an outer sleeve 2, a partition 3, an inner sleeve, and a bottom blocking plate 4. The inner sleeve includes a first component 31 and a second component 32, which are symmetrically arranged on both sides of the partition 3. The partition 3 fits tightly with the inner sleeve. The outer wall of the inner sleeve is fitted against the inner wall of the duct 1. Both the first component 31 and the second component 32 are semi-circular tubes, with appropriate beveled cuts on their axial end faces to facilitate installation. Through holes are correspondingly provided on the first component 31 and the second component 32 according to the position of the heat exchange tube, allowing the inner cavity of the inner sleeve to communicate with the heat exchange tube cavity. The width of the partition 3 is slightly smaller than the inner diameter of the duct 1, and the outer diameter of the first component 31 and the second component 32 is slightly smaller than the inner diameter of the duct 1.

[0048] During installation, first insert kit 1 (31) and kit 2 (32) into their respective positions inside duct 1, and finally insert partition 3 to ensure a tight fit between partition 3 and the inner sleeve. The gap between duct 1 and the inner sleeve can be filled with castable refractory.

[0049] Example 3

[0050] A magnesium electrolysis heat exchanger includes the protection device described in Example 1 or Example 2. Figure 4 As shown. Preferably, the aforementioned protective device is installed at both the air inlet and outlet pipes of the heat exchanger. The simultaneous installation of the protective device at both the air inlet and outlet pipes ensures that all critical components of the heat exchanger are adequately protected, thereby improving the overall safety and reliability of the equipment.

[0051] The protection device employs a triple protection design of "combined isolation + reinforced protective sleeve + filling refractory," effectively preventing the electrolyte from eroding and corroding the heat exchanger's duct 1 during operation. The outer sleeve 2 and the bottom blocking plate 4 combine to form a physical barrier, preventing the electrolyte from directly contacting the internal components; the protective sleeve 7 is made of corrosion-resistant, high-strength material, further enhancing the corrosion resistance of the welded areas; and the filling refractory serves to seal, insulate, and reinforce the structure. These three elements work together to effectively ensure the stable operation of the heat exchanger under complex conditions, significantly extending its service life.

[0052] In practical applications, allowing magnesium electrolysis heat exchangers equipped with protective devices to operate normally in magnesium electrolysis cells extends their service life from 12-14 months in traditional devices to more than 24 months, significantly improving work efficiency and system stability, and demonstrating promising prospects for industrial applications.

[0053] It should be noted that all terms used in this invention to indicate direction and position, such as "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "inner", "outer", "top", "lower", "tail end", "head end", "center", etc., are only used to explain the relative positional relationship and connection between components in a specific state. They are only for the convenience of describing this invention and do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0054] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A protection device for a magnesium electrolysis heat exchanger, wherein the magnesium electrolysis heat exchanger includes a duct (1) and at least two sets of heat exchange tube groups (5), the duct (1) including an inlet duct or an outlet duct, and each set of heat exchange tube groups (5) including a plurality of heat exchange tubes; during operation, a high-temperature molten electrolyte immerses the welded joint between the heat exchange tubes (5) and the duct (1), characterized in that, The protective device includes an outer sleeve (2) and a bottom blocking plate (4). The protective device is used to improve the reliability of the heat exchanger duct (1). The outer sleeve (2) is fitted over the outside of the duct (1) and encapsulates the welded part of the duct (1) and the heat exchange tube (5) in the space formed between the outside of the duct (1) and the inside of the outer sleeve (2). The bottom blocking plate (4) is connected to the bottom of the outer sleeve (2) and the duct (1) to seal the bottom of the outer sleeve (2) and the duct (1). At least two independent cavities are provided inside the duct (1), and each cavity is connected to the air duct of at least one set of heat exchange tubes (5) to realize the isolation and parallel flow of the airflow path.

2. The protection device according to claim 1, characterized in that, The gap between the air duct (1) and the outer casing (2) is filled with castable refractory.

3. The protection device according to claim 1, characterized in that, The air duct (1) is provided with a partition (3), which divides the air duct (1) into two independent cavities.

4. The protection device according to claim 3, characterized in that, The lower half of the air duct (1) near the liquid surface has a cut, which is opened along the axial symmetrical plane of the air duct (1) to realize the embedded installation of the partition (30).

5. The protection device according to claim 4, characterized in that, The length of the cut is equal to the length of the partition (3).

6. The protection device according to claim 3, characterized in that, An inner sleeve is also installed inside the air duct (1).

7. The protection device according to claim 1, characterized in that, According to the position of the heat exchange tube, a corresponding through hole is provided on the outer casing (2), and the heat exchange tube passes through the through hole and connects to the outer wall of the air duct (1).

8. The protection device according to claim 1, characterized in that, The protective device also includes a protective sleeve (7), which is located inside the outer sleeve (2), connected to the heat exchange tube and the air duct (1), and covers the welding area between the heat exchange tube and the air duct (1).

9. The protection device according to claim 1, characterized in that, The protective device is installed at both the air inlet pipe and the air outlet pipe.

10. A magnesium electrolysis heat exchanger, characterized in that, The heat exchanger includes the protection device as described in any one of claims 1-9.

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