Pasting type heat tracing device

Abstract

A layer of heat energy transmission material is laid on the surface of a heat-traced pipeline, a certain number of tube pipes are laid on the surface of the heat energy transmission material to serve as heat tracing pipes, the tube heat tracing pipes are connected to a flange, a valve and a support through clamping sleeves, and then hard or semi-hard circular heat preservation material products are wrapped outside the tube heat tracing pipes. The pasting type heat tracing device has the advantages of being high in heat efficiency, even and reliable in heat tracing, low in energy consumption, convenient to construct and maintain and the like.

Description

Technical Field

[0001] The present invention belongs to the fields of petrochemical industry and coal chemical industry, and particularly relates to a pasting type heat tracing device and a heat tracing method for heat tracing of pipelines or equipment. Background Art

[0002] There are three common ways of heat tracing for pipelines and equipment in petrochemical and coal chemical plants. The first way is to use heat tracing pipes. Several pipelines with a nominal diameter of DN15 or DN20 are used as heat tracing pipes. They are in contact with the main pipe to be heat traced through bundling materials and heat the main pipe. The whole system is then wrapped with hard or semi-hard circular thermal insulation material products. On this basis, some users also increase the heat transfer efficiency by adding thermal conductive putty.

[0003] The second way is to use jacketed pipes for heat tracing. A layer of metal jacket is installed outside the process pipeline, similar to a jacketed heat exchanger. In theory, as long as the temperature of the heat medium is the same as or slightly higher than the temperature of the medium in the inner pipe, the temperature of the medium in the inner pipe can be maintained.

[0004] The third way is to use electric heat tracing. By using the method of heating the pipeline with resistance wires, the biggest drawback of this method is that the contact area between the heating element and the pipeline to be heat traced is small, and the heating element is prone to open circuit, resulting in problems such as uneven and unreliable heat tracing, as well as large initial investment and high energy consumption.

[0005] For some petrochemical processes, such as sulfur recovery, maleic anhydride, polyester, and asphalt plants, some special process media such as liquid sulfur, molten salt, polyester, and asphalt require relatively strict temperature maintenance to prevent crystallization or solidification. The general heat tracing method using heat tracing pipes cannot meet the technical requirements. Among them, some users have adopted the heat tracing method of adding thermal conductive putty. Restricted by the organizational structure of powder materials, the thermal conductivity of thermal conductive putty has reached its bottleneck. The thermal conductivity coefficients of products at home and abroad are all between 14 and 18, and many occasions that require higher thermal conductivity cannot be satisfied. In addition, the construction quality of thermal conductive putty is restricted by the quality of construction personnel. During construction, corners are often cut to speed up the construction, resulting in the gaps between pipelines not being filled with materials, leading to poor thermal conductivity and so on.

[0006] Therefore, jacket heating is usually adopted for these special process media in engineering. However, jacket pipes have inherent defects. All the inner pipe welds need to be subjected to 100% radiographic inspection, with a long construction period, high construction difficulty, high construction cost, and being not suitable for heating high-temperature and high-pressure media. In addition, when the inner pipe leaks, it is often very difficult to locate the leakage point. The heating cavity may cause irregular flow field in the inner cavity due to the installation problem of the positioning plate, resulting in erosion corrosion. The thermal stress generated by the different operating temperatures and materials of the inner and outer pipe media in jacket heating is also different, which limits the diameter and length of the jacket pipe. Moreover, if the medium in the inner pipe of the jacket pipe heating is a high-pressure medium, such as the slurry pipeline in the reactor of a slurry bed hydrogenation unit, with an operating temperature of 432°C and an operating pressure of 16 MPa. If the jacket form is adopted, since the inner pipe is a high-pressure stainless steel pipeline, the corresponding outer pipe should also be made of stainless steel, resulting in too high investment costs and no usage experience at home and abroad. Because the inner pipe is a high-pressure pipeline, once the inner pipe leaks, pipe explosion will occur, even endangering the system and personal safety. Therefore, many enterprises try not to choose the jacket pipe heating method.

[0007] Currently, there are already heating patents CN217422468U, a steam heating structure, and CN213018305U, an outdoor pipeline protection device, which involve a steam heating structure. mainly, the steam pipeline transfers heat and provides heating through the partition fins arranged inside the pipeline or valve. Although the efficiency of this method has been improved, it still cannot meet the heating requirements of special media such as liquid sulfur, molten salt, polyester, and asphalt.

[0008] In view of the above situation, for the heating of special media such as liquid sulfur, molten salt, polyester, and asphalt, a new heating system and heating method with higher heat conduction efficiency, convenient construction, and more economical investment costs are urgently needed. Summary of the Invention

[0009] To solve the above problems, the present invention provides a patch-type heating device, which has the characteristics of high thermal efficiency, uniform heating, reliability, low energy consumption, convenient construction and maintenance, etc.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A patch-type heating device, characterized in that: a layer of heat transfer material is laid on the surface of the pipeline to be heated, and a certain number of tube pipes are laid on the surface of the heat transfer material as heating pipes. The tube heating pipes are connected to flanges, valves, and brackets through ferrule connections, and then a rigid or semi-rigid circular heat insulation material product is wrapped outside.

[0012] The patch-type heating device of the present invention is further characterized in that: according to the different temperatures maintained by the medium to be heated and the pipe diameter, the number of the heating pipes is generally 1 to 8.

[0013] A paste-type heat tracing device of the present invention further features that: the heat energy transmission material is ceramic, polymer or metal with high thermal conductivity and low hardness, such as aluminum alloy, aluminum-magnesium alloy, graphene, etc. The heat energy transmission material has good ductility and can be machined on-site according to the actual object, and can be perfectly fitted with different outer surfaces and the heat traced pipe.

[0014] A paste-type heat tracing device of the present invention further features that: the heat energy transmission material can be in the forms of aluminum, copper, graphene heating film, etc.

[0015] A paste-type heat tracing device of the present invention further features that: the tube heat traced pipe can be spirally wound according to the heat tracing requirement, or a π-shaped bend can be used at intervals for high-temperature stress compensation. The π-shaped bend is pasted on the outside of the object to be heat traced to achieve stress or displacement compensation.

[0016] A paste-type heat tracing device of the present invention further features that: when the tube heat traced pipe passes through a large-diameter flange, valve or equipment nozzle, the heat traced pipe can also be wound at the flange or the nozzle neck to achieve dead-point-free heat tracing.

[0017] A paste-type heat tracing device of the present invention further features that: the tube heat traced pipe can be a whole pipeline in the insulation layer, without welds and flange connections, and there are no leakage points, which is very safe.

[0018] As a preferred technical solution of the invention, the tube heat traced pipe uses a ferrule connection at the raised places such as flanges, which is convenient for disassembly and assembly.

[0019] As a preferred technical solution of the invention, the tube heat traced pipe is made of stainless steel with a wall thickness of 1 to 5 millimeters.

[0020] As a preferred technical solution of the invention, the tube heat traced pipe is embedded or wrapped in the heat energy transmission material to increase the heat transfer area.

[0021] As a preferred technical solution of the invention, steam supply and drainage points can be set according to the characteristics of the medium in the pipe and the conveying distance.

[0022] As a preferred technical solution of the invention, when the tube heat traced pipe heats the special-shaped objects such as flanges and valves, it can be fitted by cold bending or hot bending. For occasions with extremely complex shapes and strict heat tracing requirements, the surface of the object to be heat traced can be scanned by three-dimensional laser or three-dimensional surveying on-site, and a mold can be made in the factory, and then precision manufacturing can be carried out according to the mold.

[0023] As a preferred technical solution of the invention, according to the requirements of the construction party or the construction period, heat transfer materials such as pure aluminum can be prefabricated in a mold factory, which can shorten the construction period, and heat transfer materials such as pure aluminum can be bent and cut arbitrarily, enabling the heat transfer material to perfectly fit the pipe or equipment to be traced.

[0024] As a preferred technical solution of the invention, the rigid or semi-rigid circular thermal insulation material products can adopt new thermal insulation materials such as aerosol and nano-porous thermal insulation felt.

[0025] As a preferred technical solution of the invention, optionally: a surface thermometer can be added to the surface of the heat transfer material to achieve precise tracing temperature control.

[0026] The present invention provides a patch-type high-efficiency tracing device, which is a new tracing method that provides heating and insulation for equipment or pipelines by attaching a heat transfer material to the outer surface of the equipment or pipeline and adding a heat source. This high-efficiency tracing method can use various types of heat transfer materials, such as polymers and metals with high thermal conductivity and low hardness. It can not only be cut arbitrarily according to the size and length of the equipment or pipeline, but also make the inner surface of the heat transfer material perfectly fit the shape of the equipment or pipeline through special tools. Compared with the traditional tracing methods of tracing pipes and jacketed pipes, this patch-type tracing method has higher heat transfer efficiency, better application range, shorter construction period, more economical construction cost and higher safety, so it can play a role in a variety of industrial applications, including the chemical industry, the pharmaceutical industry, the food industry, and so on.

[0027] The beneficial effects of adopting the present invention are as follows:

[0028] 1) In the technical solution of the present invention, the tracing pipe has a large contact area with the pipe to be traced, high thermal efficiency, uniform tracing, reliability, and low energy consumption;

[0029] 2) The processing cost of the present invention is low, it is easy to construct, and it can be modularly designed;

[0030] 3) The present invention basically does not require maintenance, can be installed for a long time, and has good practicability and feasibility;

[0031] 4) In the technical solution of the present invention, compared with jacketed tracing, the internal leakage points are easy to check and the maintenance is convenient and fast;

[0032] 5) In the technical solution of the present invention, a surface thermometer can be set to achieve precise temperature monitoring.

[0033] 6) In the technical solution of the present invention, the tracing pipe can make stress compensation on the surface of the pipe to be traced to prevent stress damage.

[0034] 7) In the technical solution of the present invention, the tracing pipe is connected by a ferrule when passing through a valve or a bracket, which is convenient for installation.

[0035] 8) In the technical solution of the present invention, when the tracing pipe passes through a flange (valve) or the pipe orifice of a device, dead - point - free installation and pasting can be achieved, and the tracing is more uniform and the effect is better. For example, in pipelines or devices that require it, especially in large - scale devices, molten salt pipelines, asphalt pipelines, sulfur pipelines, polyester and fertilizer pipelines, etc., in order to prevent local coagulation, these media require more uniform and reliable tracing. The technical solution of the present invention can perfectly meet these requirements.

[0036] 9) The heat - energy transmission material described in the technical solution of the present invention has good ductility and can be perfectly fitted to the traced pipe according to different outer surfaces.

[0037] 10) The present invention also has the advantages of strong practicability, simple structure, easy implementation, wide application range, etc.

[0038] The following further elaborates on the present invention in conjunction with the accompanying drawings and specific embodiments, but does not limit the scope of use of the present invention. Brief Description of the Drawings

[0039] Figure 1 is a schematic structural diagram of a pasting - type tracing device of the present invention;

[0040] Figure 2 is Figure 1 a side view of

[0041] Figure 3 is a schematic structural diagram of the present invention with stress compensation;

[0042] Figure 4 is a schematic structural diagram of the present invention passing through flanges, brackets, etc.

[0043] The reference numerals shown in the figures are: 1 - rigid or semi - rigid circular heat - insulating material, 2 - heat - energy transmission material, 3 - traced pipe, 4 - tube tracing pipe, 5 - surface thermometer, 6 - ferrule, 7 - flange, 8 - bracket, 9 - valve. Detailed Description of the Embodiments

[0044] The following further describes the present invention in conjunction with the Figures 1-4 accompanying drawings.

[0045] As shown in the Figure 1 and Figure 2As shown in the figure, for the rigid or semi-rigid circular thermal insulation material 1 of the present invention, aluminosilicate wool and its products are selected, and the insulation thickness is 60 mm; for the heat energy transmission material 2, industrial pure aluminum (hardness 25 - 32 HB) is selected, with a thickness of 6 mm and an unfolded width of 90 mm; the pipe to be traced 3 is an alloy steel pipeline (DN100 SCH80); the tube tracing pipe 4 uses a φ12 stainless steel tube with a thickness of 1.5 mm.

[0046] The industrial pure aluminum of the heat energy transmission material 2 is machined and closely attached to the surface of the alloy steel pipeline of the pipe to be traced 3; the tube tracing pipe 4 is wrapped inside or outside by the industrial pure aluminum of the heat energy transmission material 2 through machining, and the tube tracing pipe 4 and the heat energy transmission material 2 are wrapped outside by the rigid or semi-rigid circular thermal insulation material 1, aluminosilicate wool and its products; the surface thermometer 5 is used to measure the surface temperature of the pipe to be traced 3 to achieve precise monitoring.

[0047] The entire tracing process is that steam heats the tube tracing pipe 4, the tube tracing pipe 4 conducts heat to the heat energy transmission material 2, and the heat energy transmission material 2 conducts heat to the pipe to be traced 3, thereby achieving the purpose of tracing and heat preservation. The temperature of the pipe to be traced 3 is controlled by adjusting the steam temperature and flow rate.

[0048] Figure 3 This is a schematic structural diagram of the present invention with stress compensation. The 4-tube tracing pipe walks several π-shaped patterns on the surface of the 3-pipe to be traced. In this way, when the tracing pipe expands thermally, the π-shaped bend can absorb the thermal expansion displacement of the tracing pipe.

[0049] Figure 4 This is a schematic structural diagram of the present invention passing through flanges and brackets, etc. When the 4-tube tracing pipe passes through the 7-flange or the 8-bracket, the 4-tube tracing pipe is connected by the 6-ferrule, and the installation is very convenient.

[0050] As a preferred technical solution of the invention, the calculation and analysis example of the tracing effect is as follows: For a DN100 molten salt pipeline in a maleic anhydride plant, the wall thickness is SCH80, and the material is A335P11 alloy steel; the inside of the pipeline is molten salt, and the temperature is taken as the normal temperature of 0 °C. Two quarter-circular aluminum plates with a thickness of 6 mm are pasted on the outer wall of the pipeline. The φ12 tube tracing pipes are arranged in grooves on the aluminum plates. The material of the stainless steel tube tracing pipe is internally passed with steam at a temperature of 236 °C and a pressure of 1.2 MPa; the thermal insulation material is aluminosilicate magnesium and its products, and the thermal insulation thickness is 60 mm; the air ambient temperature is taken as the extremely low temperature of -19.2 °C, the extremely high wind speed is 32 m / s, and the air convection coefficient is 123 W / m 2 / °C. The temperature distributions of the molten salt in the pipeline are obtained by using conventional steam tracing, heat tracing clay steam tracing, and the pasting type high-efficiency tracing of the present invention respectively.

[0051] Calculation results of the inner wall temperature of molten salt pipelines with different tracing types:

[0052]

[0053]

[0054] As can be seen from the results in the table, the present invention provides a patch-type high-efficiency heat tracing device and a heat tracing method, and the effect is significantly better than the traditional heat tracing method. The lowest temperature on the inner wall of the pipeline can meet the requirement of being 180 °C higher than the molten salt maintenance temperature, and it can perfectly replace the jacket heat tracing.

[0055] The above are only typical embodiments of the present invention, and there is no any formal limitation on the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, the changes or modifications made using the above content should be regarded as equivalent examples of equivalent changes. All content that does not depart from the technical solution of the present invention, any equivalent changes made to the above embodiments according to the technical essence of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A patch-type heat tracing device, characterized in that: Lay a layer of heat transfer material on the surface of the heat-traced pipeline, and lay a certain number of tube pipes on the surface of the heat transfer material as heat tracing pipes. The tube heat tracing pipes are connected to flanges, valves and brackets through ferrule connections, and then wrapped with hard or semi-hard circular thermal insulation material products on the outside.

2. The applicator-type tracing device according to claim 1, wherein: According to the different temperatures maintained by the heat-traced medium and the pipe diameters, the heat tracing pipes are generally 1 to 8 in number.

3. The attached heat tracing device according to claim 1, wherein: The heat transfer material is ceramic, polymer or metal with high thermal conductivity and low hardness.

4. The attached heating device according to claim 3, characterized in that: The heat transfer material is aluminum, copper and graphene heating film.

5. The applicator type tracing heating device according to claim 1, wherein: The tube heat tracing pipes are wound in a spiral shape according to the heat tracing requirements, or a π-shaped bend is used for high-temperature stress compensation at intervals, and the π-shaped bend is attached to the outside of the heat-traced object.

6. The patch-type tracing device according to claim 1, wherein: When the tube heat tracing pipes pass through large-diameter flanges, valves or equipment nozzles, the heat tracing pipes are also wound around the necks of the flanges or nozzles to achieve dead-point-free heat tracing.

7. The attached heat tracing device according to claim 1, characterized in that: The tube heat tracing pipes are connected by ferrule connections at raised places such as flanges.

8. The patch-type heat tracing device according to claim 1, wherein: The tube heat tracing pipes are made of stainless steel with a wall thickness of 1 to 5 millimeters.

9. The applicator type tracing heating device according to claim 1, wherein: The tube heat tracing pipes are embedded or wrapped in the heat transfer material to increase the heat transfer area.

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