Electric heating high-temperature acid-resistant protective sleeve

Abstract

The utility model provides an electric heating high-temperature acid-resistant protective sleeve, which is detachably sleeved on the periphery of the heating end of an electric heater extending into acid liquor, and comprises a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve, a tantalum acid-resistant sleeve and a tantalum acid-resistant sleeve, the shape of the heat-resistant steel pipe is matched with that of the tantalum acid-resistant sleeve, the heat-resistant steel pipe is arranged on the inner side of the tantalum acid-resistant sleeve and matched with the blind hole end in a stopping mode, and the outer wall of the heat-resistant steel pipe is matched with the inner wall of the tantalum acid-resistant sleeve in a limiting mode and provided with a through flow guide hole set; the polytetrafluoroethylene layer at least sleeves the periphery of the tantalum acid-resistant sleeve which does not extend into the acid liquor; wherein the heat-conducting medium is filled in the heat-resisting steel pipe at least extending below the acid liquid and the flow guide hole group, and the heating end of the electric heater is detachably arranged in the heat-conducting medium in the heat-resisting steel pipe in a penetrating manner. According to the technical scheme provided by the utility model, the problems of high cost and easy oxidation corrosion of an acid-resistant protective sleeve made of tantalum materials can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of equipment in the metallurgical and chemical industries, and in particular to an electrically heated, high-temperature, acid-resistant protective sleeve. Background Art

[0002] In metallurgical and chemical production processes, indirect heating of acidic solutions is often required to ensure a stable reaction material ratio. Electric heating is the most common and efficient indirect heating method. Acid-resistant protective sleeves are designed to ensure that electric heaters can operate in acidic solutions for extended periods of time.

[0003] The performance requirements for electric heating protective sleeves vary depending on the type, concentration, and operating temperature of the acid. Low-concentration, low-acidity protective sleeves are more common on the market, but high-concentration, high-temperature acid-resistant protective sleeves are primarily made of tantalum and zirconium. Only tantalum offers a long service life in high-temperature, high-concentration hydrochloric acid conditions. However, pure tantalum or tantalum alloy protective sleeves have two significant drawbacks: first, tantalum is too expensive, resulting in high production costs; second, tantalum is susceptible to hydrogen and oxygen corrosion between 200°C and 350°C. While tantalum tubes have a long service life in the acid-covered range, they are particularly susceptible to corrosion and wear when exposed to gases. Utility Model Content

[0004] The utility model provides an electrically heated high-temperature acid-resistant protective sleeve, which solves the problems that the acid-resistant protective sleeve made of tantalum is high in cost and easily oxidized and corroded.

[0005] In order to achieve the above-mentioned purpose, the utility model provides an electric heating high-temperature acid-resistant protective sleeve, which is detachably mounted on the outer periphery of the heating end of the electric heater extending into the acid liquid, and the electric heating high-temperature acid-resistant protective sleeve includes: a tantalum acid-resistant sleeve, one end of which extending into the acid liquid is a blind hole end; a heat-resistant steel pipe whose shape is adapted to the tantalum acid-resistant sleeve, which is arranged on the inner side of the tantalum acid-resistant sleeve and cooperates with the blind hole end stopper, the outer wall of the heat-resistant steel pipe is limitedly matched with the inner wall of the tantalum acid-resistant sleeve and has a through-going guide hole group; a polytetrafluoroethylene layer, which is at least mounted on the outer periphery of the tantalum acid-resistant sleeve that does not extend into the acid liquid; wherein, the interior of the heat-resistant steel pipe and the guide hole group at least extending below the acid liquid are filled with a heat-conducting medium, and the heating end of the electric heater is detachably penetrated into the heat-conducting medium in the heat-resistant steel pipe.

[0006] Furthermore, the wall thickness of the tantalum acid-resistant casing is 0.15 mm to 2 mm.

[0007] Furthermore, the wall thickness of the heat-resistant steel pipe is 1.5 mm to 4 mm.

[0008] Furthermore, the thickness of the polytetrafluoroethylene layer is 0.3 mm to 1.2 mm.

[0009] Furthermore, the electrically heated high-temperature acid-resistant protective sleeve further includes a carbon fiber layer, which is sleeved on the outer periphery of the polytetrafluoroethylene layer.

[0010] Furthermore, the thickness of the carbon fiber layer is 0.5 mm to 1.5 mm.

[0011] Furthermore, the carbon fiber layer and the polytetrafluoroethylene layer have the same extension length.

[0012] Furthermore, the guide hole group includes a plurality of guide holes, and the plurality of guide holes are distributed at intervals along the circumferential direction and / or axial direction of the heat-resistant steel pipe.

[0013] Furthermore, the diameter of the guide hole is 2 mm to 6 mm.

[0014] Furthermore, the heat transfer medium is heat transfer oil.

[0015] By applying the technical solution of the utility model, an electric heating high-temperature acid-resistant protective sleeve is provided, which is detachably mounted on the outer periphery of the heating end of the electric heater extending into the acid liquid, and the electric heating high-temperature acid-resistant protective sleeve comprises: a tantalum acid-resistant sleeve, one end of which extending into the acid liquid is a blind hole end; a heat-resistant steel pipe whose shape is adapted to the tantalum acid-resistant sleeve, which is arranged on the inner side of the tantalum acid-resistant sleeve and cooperates with the blind hole end stopper, the outer wall of the heat-resistant steel pipe is limitedly matched with the inner wall of the tantalum acid-resistant sleeve and has a through-going guide hole group; a polytetrafluoroethylene layer, which is at least mounted on the outer periphery of the tantalum acid-resistant sleeve that does not extend into the acid liquid; wherein, the interior of the heat-resistant steel pipe and the guide hole group at least extending below the acid liquid are filled with a heat-conducting medium, and the heating end of the electric heater is detachably passed through the heat-conducting medium in the heat-resistant steel pipe.

[0016] The electric heating high temperature acid-resistant protective sleeve provided by the present invention is provided with a heat-conducting medium injected into the inner layer of the heat-resistant steel pipe before use. The heat-conducting medium will be filled into the guide hole group and contact the tantalum acid-resistant sleeve. When in use, the electric heating end arranged in the heat-resistant steel pipe heats and transfers heat through the heat-conducting medium to achieve rapid heating of the tantalum acid-resistant sleeve. The heat is quickly transferred through the heat-conducting oil, thereby achieving rapid and effective heating of the acid liquid. The present invention avoids the deformation of the tantalum acid-resistant sleeve under high temperature pressure by lining the inner side of the tantalum acid-resistant sleeve with a heat-resistant steel pipe, which is beneficial to improving the service life of the electric heating high temperature acid-resistant protective sleeve. At the same time, such a setting also allows the tantalum acid-resistant sleeve to be made thinner, thereby reducing the processing cost of the tantalum acid-resistant sleeve, and improving its cost-effectiveness while ensuring the function of the electric heating high temperature acid-resistant protective sleeve. On the other hand, the present invention can achieve anti-oxidation protection of the tantalum acid-resistant sleeve by setting a polytetrafluoroethylene layer, thereby increasing the corrosion resistance of the tantalum acid-resistant sleeve and ensuring the reliability and stability of the electric heating high temperature acid-resistant protective sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of this application are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A partial structural schematic diagram of an electrically heated, high-temperature, acid-resistant protective sleeve provided by an embodiment of the utility model is shown.

[0019] The above drawings include the following reference numerals:

[0020] 1. Tantalum acid-resistant casing;

[0021] 2. Heat-resistant steel pipe; 201. Diversion hole; 202. Installation blind hole;

[0022] 3. Polytetrafluoroethylene layer;

[0023] 4. Carbon fiber layer;

[0024] 501. Gap area. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way serves as any limitation on the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the utility model provides an electric heating high-temperature acid-resistant protective sleeve, which is detachably mounted on the outer periphery of the heating end of the electric heater extending into the acid liquid, and the electric heating high-temperature acid-resistant protective sleeve comprises: a tantalum acid-resistant sleeve 1, one end of which extending into the acid liquid is a blind hole end; a heat-resistant steel pipe 2 whose shape is adapted to the tantalum acid-resistant sleeve 1, which is arranged on the inner side of the tantalum acid-resistant sleeve 1 and cooperates with the blind hole end stopper, the outer wall of the heat-resistant steel pipe 2 is limitedly matched with the inner wall of the tantalum acid-resistant sleeve 1 and has a through-going guide hole group; a polytetrafluoroethylene layer 3, which is at least mounted on the outer periphery of the tantalum acid-resistant sleeve 1 that is not extended into the acid liquid; wherein, the interior of the heat-resistant steel pipe 2 extending at least below the acid liquid and the guide hole group are filled with a heat-conducting medium, and the heating end of the electric heater is detachably penetrated into the heat-conducting medium in the heat-resistant steel pipe 2.

[0027] The electrically heated high-temperature acid-resistant protective sleeve provided in this embodiment is first injected with a heat-conducting medium into the inner layer of the heat-resistant steel pipe 2 before use. The heat-conducting medium will fill the guide hole group and contact the tantalum acid-resistant sleeve 1. When in use, the electric heating end arranged in the heat-resistant steel pipe 2 heats and transfers heat through the heat-conducting medium to achieve rapid heating of the tantalum acid-resistant sleeve 1. The heat is quickly transferred through the heat-conducting oil, thereby achieving rapid and effective heating of the acid liquid. This embodiment avoids the deformation of the tantalum acid-resistant casing 1 under high temperature pressure by lining the inner side of the tantalum acid-resistant casing 1 with a heat-resistant steel pipe 2, which is beneficial to improving the service life of the electrically heated high-temperature acid-resistant protective casing. At the same time, this arrangement also allows the tantalum acid-resistant casing 1 to be made thinner, thereby reducing the processing cost of the tantalum acid-resistant casing 1, and improving its cost-effectiveness while ensuring the function of the electrically heated high-temperature acid-resistant protective casing. On the other hand, this embodiment can achieve anti-oxidation protection for the tantalum acid-resistant casing 1 by providing a polytetrafluoroethylene layer 3, thereby increasing the corrosion resistance of the tantalum acid-resistant casing 1, and thus ensuring the reliability and stability of the electrically heated high-temperature acid-resistant protective casing.

[0028] Specifically, if Figure 1 As shown, the shape of the heat-resistant steel pipe 2 is adapted to the tantalum acid-resistant sleeve 1 and also has a blind hole end, which has an upward-opening mounting blind hole 202, and the heating end of the electric heater is pluggable and inserted into the mounting blind hole 202 through the opening of the mounting blind hole 202.

[0029] It should be noted that the heat-resistant steel pipe 2 can be filled with heat-conducting medium before the electric heater is powered on for heating. Alternatively, an appropriate amount of heat-conducting medium can be injected into the heat-resistant steel pipe 2 before the heating end of the electric heater is inserted into the heat-resistant steel pipe 2.

[0030] It is understandable that the heat generated by the electric heater is quickly transferred to the tantalum acid-resistant sleeve 1 through the heat-conducting medium, which can also effectively reduce the temperature of the heating end surface of the electric heater and extend the service life of the electric heater.

[0031] Preferably, there may be a small gap between the tantalum acid-resistant casing 1 and the heat-resistant steel pipe 2, that is, Figure 1 In the illustrated gap region 501, the heat-conducting medium is filled through the guide hole group, further increasing the heat transfer area and heat transfer effect to the tantalum acid-resistant casing 1. It will be understood that the gap formed between the heat-resistant steel tube 2 and the tantalum acid-resistant casing 1 should be large enough to ensure that the heat-resistant steel tube 2 has a structural reinforcement effect on the tantalum acid-resistant casing 1 while increasing the heat transfer area and heat transfer effect.

[0032] It should be noted that the bottom end of the polytetrafluoroethylene layer 3, which is sleeved on the periphery of the tantalum acid-resistant casing 1 that does not extend into the acid solution, extends to the liquid level of the acid solution or extends below the liquid level of the acid solution. In the present embodiment, the polytetrafluoroethylene layer 3 does not need to completely coat the tantalum acid-resistant casing 1. It mainly coats the tantalum acid-resistant casing 1 to a certain height from the acid solution liquid level upwards, and a small portion can be allowed to extend below the acid solution liquid level. Preferably, the periphery of the tantalum acid-resistant casing 1 that extends below the acid solution liquid level is not coated with the polytetrafluoroethylene layer 3 to avoid affecting the electric heating effect of the acid solution.

[0033] The wall thickness of the tantalum acid-resistant casing 1 is 0.15 mm to 2 mm. This configuration avoids the situation where the tantalum acid-resistant casing 1 is too thin and thus has poor acid resistance. It also avoids the problem where the tantalum acid-resistant casing 1 is too thick and thus has poor electric heating effect and is too heavy. This ensures the acid resistance of the tantalum acid-resistant casing 1 while reducing its weight, thereby improving its cost-effectiveness.

[0034] Specifically, the wall thickness of the heat-resistant steel pipe 2 is 1.5 mm to 4 mm. This configuration avoids the situation where the heat-resistant steel pipe 2 is too thin, resulting in a lack of significant structural reinforcement effect on the tantalum acid-resistant casing 1. It also avoids the problem of the heat-resistant steel pipe 2 being too thick, resulting in poor electric heating effect and heavy weight. This allows the heat-resistant steel pipe 2 to withstand pressure in high-temperature environments while ensuring relatively good thermal conductivity and reliability.

[0035] Furthermore, the thickness of the polytetrafluoroethylene layer 3 is 0.3 mm to 1.2 mm. This configuration avoids the situation where the polytetrafluoroethylene layer 3 is too thin, resulting in poor anti-oxidation protection for the outer periphery of the tantalum acid-resistant casing 1, and also avoids the situation where the polytetrafluoroethylene layer 3 is too thick, resulting in a heavy polytetrafluoroethylene layer 3 and a waste of cost, thereby ensuring the reliability and functionality of the polytetrafluoroethylene layer 3.

[0036] like Figure 1 As shown, the electrically heated high-temperature acid-resistant protective sleeve further includes a carbon fiber layer 4, which is sleeved on the outer periphery of the polytetrafluoroethylene layer 3. The carbon fiber layer 4 can control the orderly expansion of the polytetrafluoroethylene layer 3, thereby increasing the service life of the polytetrafluoroethylene layer 3.

[0037] Specifically, the thickness of the carbon fiber layer 4 is 0.5 mm to 1.5 mm. This configuration avoids the situation where the carbon fiber layer 4 is too thin, resulting in poor protection of the polytetrafluoroethylene layer 3, and also avoids the situation where the carbon fiber layer 4 is too thick, resulting in a large weight and cost waste, thereby ensuring the reliability and functionality of the carbon fiber layer 4.

[0038] Preferably, the carbon fiber layer 4 and the polytetrafluoroethylene layer 3 have the same extension length. Specifically, both ends of the carbon fiber layer 4 are flush with both ends of the polytetrafluoroethylene layer 3.

[0039] Such an arrangement is conducive to ensuring the protective effect of the carbon fiber layer 4 on the polytetrafluoroethylene layer 3, avoiding the situation where part of the polytetrafluoroethylene layer 3 cannot be protected when the extension length of the carbon fiber layer 4 is less than the polytetrafluoroethylene layer 3, or avoiding the situation where part of the carbon fiber layer 4 is wasted when the extension length of the carbon fiber layer 4 is greater than the polytetrafluoroethylene layer 3.

[0040] The guide hole group includes a plurality of guide holes 201, and the plurality of guide holes 201 are distributed along the circumference and / or axial direction of the heat-resistant steel pipe 2. Figure 1 As shown, the guide hole group includes multiple layers distributed axially along the heat-resistant steel tube 2, and each layer includes multiple guide holes 201 distributed circumferentially along the heat-resistant steel tube 2. The multiple guide holes 201 have the same radial dimensions and extend parallel to the radial direction of the heat-resistant steel tube 2. Each layer has the same number of guide holes 201, and the multiple guide holes 201 in any two adjacent layers are arranged in a corresponding manner along the axial direction of the heat-resistant steel tube 2. This arrangement allows the tantalum acid-resistant casing 1 corresponding to any guide hole 201 to be heated by the heat transfer oil, ensuring comprehensive and uniform heat transfer to the tantalum acid-resistant casing 1.

[0041] It is understandable that the extension direction, shape and distribution of the guide holes 201 and the like can be adjusted according to actual conditions to ensure uniformity and reliability of heating of the portion of the tantalum acid-resistant casing 1 extending into the acid solution.

[0042] Specifically, the diameter of the guide hole 201 is 2 mm to 6 mm. This configuration avoids the situation where the guide hole 201 is too small, resulting in poor heat transfer effect of the heat-conducting medium inside the tantalum acid-resistant casing 1, and avoids the situation where the guide hole 201 is too large, resulting in it affecting the structural strength of the heat-resistant steel pipe 2.

[0043] Among them, the heat-conducting medium in this embodiment is heat-conducting oil, which has a better heat transfer effect and is more conducive to the rapid heating of the acid liquid by the electric heater.

[0044] Preferably, QD350 or similar heat transfer oil is used as the high-temperature resistant heat transfer oil. This type of heat transfer oil has high thermal stability and is suitable for high-temperature heating systems, effectively improving heating efficiency and reducing energy consumption.

[0045] It should be noted that the power of a single electric heater is 5kW to 8kW. This power range can meet industrial heating needs while ensuring safe operation of the equipment, and is suitable for industrial heating applications of all sizes.

[0046] In a specific embodiment, the operating conditions and related parameters of the electrically heated high-temperature acid-resistant protective sleeve are as follows: acid (hydrochloric acid) concentration: 31%; temperature: 175°C; pressure: 1.0 MPa; solid content: 150 g / L; power of a single electric heater: 6 kW (380 V); the outer diameter of the heat-resistant steel pipe 2 is 60 mm, the wall thickness of the heat-resistant steel pipe 2 is 4 mm, and the extended length of the heat-resistant steel pipe 2 is 1500 mm; the inner diameter of the tantalum acid-resistant sleeve 1 is 60 mm. .5mm, the wall thickness of the tantalum acid-resistant sleeve 1 is 2mm, and the extended length of the tantalum acid-resistant sleeve 1 is 1500mm; there are 300 guide holes and each hole diameter is 6mm; the thickness of the polytetrafluoroethylene layer 3 is 0.5mm, and the extended length of the polytetrafluoroethylene layer 3 is 550mm (50mm deep into the acid liquid surface); the thickness of the carbon fiber layer 4 is 0.5mm, and the extended length of the carbon fiber layer 4 is 550mm; the thermal oil brand is QD350. In this embodiment, the tantalum acid-resistant sleeve 1 and the heat-resistant steel pipe 2 have the same extended length and are flush, the polytetrafluoroethylene layer 3 and the carbon fiber layer 4 have the same extended length and are flush, and there is an annular gap area 501 with a thickness of 0.25mm between the tantalum acid-resistant sleeve 1 and the heat-resistant steel pipe 2. The high-temperature acid-resistant protective sleeve provided in this embodiment has a service life of more than 5 years under the above-mentioned working conditions, while the service life of the pure tantalum protective sleeve is less than half a year. If pure tantalum or its alloy is used to make a protective sleeve with the same outer diameter, the wall thickness of the tube is at least 5 mm, and its manufacturing cost is more than double that of the above-mentioned patent solution.

[0047] In summary, the high-temperature acid-resistant protective sleeve provided in this embodiment avoids the deformation of the tantalum acid-resistant sleeve 1 under high temperature pressure by lining the inner side of the tantalum acid-resistant sleeve 1 with a heat-resistant steel pipe 2, which is beneficial to improving the service life of the electrically heated high-temperature acid-resistant protective sleeve. At the same time, such a setting also allows the tantalum acid-resistant sleeve 1 to be made thinner, thereby reducing the processing cost of the tantalum acid-resistant sleeve 1, while ensuring the function of the electrically heated high-temperature acid-resistant protective sleeve and improving its cost-effectiveness, providing technical guarantee for the metallurgical and chemical industry to promote indirect heating of acid-containing slurries by electricity.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0049] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0050] In the description of the present invention, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0051] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0052] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this utility model.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An electrically heated, high-temperature, acid-resistant protective sleeve, which is detachably sleeved on the outer periphery of the heating end of the electric heater extending into the acid solution, characterized in that: The electrically heated high-temperature acid-resistant protective sleeve comprises: A tantalum acid-resistant casing (1), one end of which extends into the acid liquid is a blind hole end; A heat-resistant steel pipe (2) having a shape adapted to the tantalum acid-resistant casing (1) is arranged on the inner side of the tantalum acid-resistant casing (1) and cooperates with the blind hole end stopper; the outer wall of the heat-resistant steel pipe (2) is limitedly matched with the inner wall of the tantalum acid-resistant casing (1) and has a through-going guide hole group; A polytetrafluoroethylene layer (3) is at least sleeved on the outer periphery of the tantalum acid-resistant sleeve (1) which does not extend into the acid liquid; Wherein, at least the interior of the heat-resistant steel pipe (2) extending into the acid solution and the guide hole group are filled with a heat-conducting medium, and the heating end of the electric heater is detachably inserted into the heat-conducting medium in the heat-resistant steel pipe (2).

2. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The wall thickness of the tantalum acid-resistant casing (1) is 0.15 mm to 2 mm.

3. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The wall thickness of the heat-resistant steel pipe (2) is 1.5 mm to 4 mm.

4. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The thickness of the polytetrafluoroethylene layer (3) is 0.3 mm to 1.2 mm.

5. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The electrically heated high-temperature acid-resistant protective sleeve further comprises a carbon fiber layer (4), and the carbon fiber layer (4) is sleeved on the outer periphery of the polytetrafluoroethylene layer (3).

6. The electrically heated high-temperature acid-resistant protective sleeve according to claim 5, characterized in that: The thickness of the carbon fiber layer (4) is 0.5 mm to 1.5 mm.

7. The electrically heated high-temperature acid-resistant protective sleeve according to claim 5, characterized in that: The carbon fiber layer (4) and the polytetrafluoroethylene layer (3) have the same extension length.

8. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The guide hole group comprises a plurality of guide holes (201), and the plurality of guide holes (201) are distributed at intervals along the circumferential direction and / or axial direction of the heat-resistant steel pipe (2).

9. The electrically heated high-temperature acid-resistant protective sleeve according to claim 8, characterized in that: The diameter of the guide hole (201) is 2 mm to 6 mm.

10. The electrically heated high-temperature acid-resistant protective sleeve according to claim 1, characterized in that: The heat transfer medium is heat transfer oil.

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