Heat preservation and insulation device for downcomer of blast furnace

Abstract

The utility model belongs to the field of iron-making blast furnace pipeline heat preservation devices, and relates to a heat preservation and insulation device for a blast furnace downcomer, which is used for heat preservation of the downcomer and comprises a heat preservation structure and an inflation system, the heat preservation structure is a sealed cavity sleeved outside the blast furnace downcomer, and the inflation system is communicated with the sealed cavity. And the sealing cavity is filled with gas so as to realize heat insulation. According to the utility model, gas heat insulation is adopted as a heat preservation structure of the blast furnace downcomer, which is an innovative design breaking through the tradition. Different from conventional heavy heat insulation materials such as rock wool, low-heat-conduction gas in the sealed cavity is used as a heat insulation medium for gas heat insulation, and the heat insulation material has the remarkable advantages of being light in weight and excellent in heat insulation effect.

Description

Technical Field

[0001] This utility model belongs to the field of blast furnace pipeline insulation device, and relates to a blast furnace downcomer insulation device. Background Technology

[0002] In blast furnace smelting, the temperature control of the blast furnace top gas is a key parameter affecting fuel utilization and equipment safety. Industry practice shows that lowering the blast furnace top gas temperature helps improve the chemical energy utilization rate of the gas, thereby reducing fuel consumption and optimizing blast furnace technical indicators. However, this operation can trigger a chain reaction of system temperature drop: when the blast furnace top gas is transported to the dry dust collector via the riser, downcomer, and gravity dust collector, the temperature typically drops by 25-40℃. This temperature drop easily causes condensation on the filter bags due to the gas temperature approaching the dew point, leading to dust adhesion, bag caking, and other problems, seriously affecting dust removal efficiency and bag lifespan. Therefore, under the premise of ensuring the safe operation of the dust removal system, how to reduce the temperature drop of the blast furnace gas from the top to the inlet of the dry dust collector to achieve lower blast furnace top temperature control has become an important issue for energy-saving blast furnace production.

[0003] In existing technologies, the main measures to reduce the temperature drop in gas transmission systems focus on the design of pipeline insulation structures. The blast furnace downcomer, as the core transmission channel connecting the furnace top and the gravity dust collector, despite its inner wall being designed with refractory materials, contributes over 60% of the total system temperature drop (from the blast furnace top to the dry dust collector inlet) due to its large span and long length (calculated after the riser and downcomer were not externally insulated, while the remaining pipelines were insulated with traditional rock wool). While the currently commonly used rock wool insulation material + galvanized iron sheet outer cladding structure has a certain heat insulation effect, it has revealed significant shortcomings in practical applications:

[0004] Insufficient environmental tolerance: Traditional insulation structures exposed to high-altitude environments are unable to effectively resist long-term wind and sun erosion. The galvanized iron outer layer is prone to electrochemical corrosion, leading to seal failure. Rainwater seepage not only reduces insulation performance but also significantly increases the load on pipes, posing a major safety hazard of structural collapse.

[0005] Maintenance and repair are difficult: The enclosed insulation structure completely covers the surface of the pipe, making it impossible for production personnel to visually monitor the condition of the pipe wall. When the refractory material inside the downcomer falls off, abnormalities such as high-temperature red-hot discoloration and stress cracking can easily occur in the local shell. However, existing technology lacks effective online detection methods, making it difficult to detect such hidden dangers in a timely manner, which seriously threatens the safe production of the blast furnace.

[0006] Short service life: After corrosive media penetrate the insulation layer, it not only accelerates the corrosion process of the metal shell, but also causes the rock wool material to pulverize and fail, resulting in a short effective service life of this type of structure. Frequent replacement increases maintenance costs and affects the continuous production of the blast furnace.

[0007] To address the aforementioned technical bottlenecks, there is an urgent need to develop new insulation structure solutions for blast furnace downcomers. These solutions should ensure effective temperature drop control while addressing the problems of poor environmental tolerance, significant safety hazards, and high maintenance costs associated with traditional structures. This will provide technical support for achieving better heat recovery and safer production in blast furnace systems. Utility Model Content

[0008] In view of this, the purpose of this utility model is to provide a heat insulation device for the blast furnace downcomer, which reduces the temperature drop of the blast furnace downcomer while avoiding safety risks, thereby providing a solution for blast furnace operators to control the low top temperature.

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] A heat insulation device for a blast furnace downcomer is provided for heat insulation of the downcomer. It includes an insulation structure and a gas filling system. The insulation structure is a sealed cavity fitted outside the blast furnace downcomer. The gas filling system is connected to the sealed cavity and is used to fill the sealed cavity with gas to achieve heat insulation.

[0011] Furthermore, it also includes a temperature alarm system, which includes a temperature measuring device installed within the insulation structure and a temperature alarm control system connected to the temperature measuring device.

[0012] Furthermore, the temperature measuring device is a distributed temperature-sensing optical fiber or a patch thermocouple.

[0013] Furthermore, the temperature measuring device is laid axially along the downcomer wall to monitor the downcomer wall temperature in real time.

[0014] Furthermore, the portion of the insulation structure near the top of the downcomer is provided with a vent valve and a pressure transmitter that connect to its sealed inner cavity, and the pressure transmitter is arranged between the vent valve and the sealed inner cavity to detect the pressure inside the sealed cavity in real time.

[0015] Furthermore, the insulation structure is formed by welding steel profiles along the axial and transverse directions of the downcomer pipe to form a skeleton, and then sealing the skeleton with corrosion-resistant steel plates to form a sealed cavity.

[0016] Furthermore, the corrosion-resistant steel plate is a color-coated steel plate or a galvanized steel plate.

[0017] Furthermore, the inflation system includes an inflation source connected to the sealed cavity and an inflation valve arranged between the inflation source and the sealed cavity.

[0018] The beneficial effects of this utility model are as follows:

[0019] 1. Innovative gas insulation design

[0020] This technical solution employs gas insulation as the thermal insulation structure for the blast furnace downcomer, representing a groundbreaking and innovative design. Unlike conventionally used heavy insulation materials such as rock wool, gas insulation utilizes a low-thermal-conductivity gas (such as air or inert gas) within a sealed cavity as the insulation medium, offering significant advantages such as lightweight and superior insulation performance. This design effectively reduces the temperature drop of the downcomer by minimizing heat conduction and convection, thus reducing the structural burden on the pipeline and enhancing the durability of the insulation structure, while also minimizing losses caused by environmental factors. This innovation not only optimizes insulation performance but also lays the foundation for the efficient operation of the blast furnace equipment.

[0021] 2. Enhanced security monitoring system

[0022] To further enhance safety, this solution integrates a pipe wall temperature monitoring and alarm system and leak detection facilities within the insulation structure. The temperature monitoring and alarm system can monitor temperature changes in the downcomer pipe wall in real time; once abnormally high temperatures are detected, an alarm is immediately triggered, prompting operators to take appropriate measures. The leak detection facilities monitor cavity pressure to promptly detect potential leaks in the insulation layer or pipes, preventing safety risks such as gas leaks. These intelligent monitoring methods compensate for the lack of real-time monitoring in traditional insulation structures, providing a safe and reliable technical guarantee for blast furnace operation and ensuring a stable and controllable production process.

[0023] 3. Practicality

[0024] The practicality of this technical solution lies in its significant optimization effect on blast furnace operation. By reducing the temperature drop in the downcomer, operators can more precisely control the top gas temperature, achieving low top temperature operation, thereby improving gas utilization efficiency, reducing energy consumption, and extending the service life of dry dust collector bags, avoiding condensation problems caused by excessive temperature drop. Furthermore, its lightweight design simplifies installation and maintenance processes, reducing operating costs. Overall, this solution provides blast furnace operators with a low top temperature control operation solution that combines high efficiency, safety, and economy, and has broad practical application value.

[0025] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1This is a schematic diagram of the structure of a blast furnace downcomer insulation device in one embodiment.

[0028] Attached reference numerals: 1-Blast furnace; 2-Rising pipe; 3-Five-way ball; 4-Downcomer; 5-Insulation structure; 6-Temperature measuring equipment; 7-Fiber optic box; 8-Temperature measuring alarm control system; 9-Gravity dust collector; 10-Inflation gas source; 11-Inflation valve; 12-Pressure transmitter; 13-Vent valve. Detailed Implementation

[0029] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] Please see Figure 1 This is a specific application scenario of a blast furnace downcomer insulation device. The blast furnace 1 is connected to the upper end of the downcomer 4 through the riser 2 and the five-way ball 3. The lower end of the downcomer 4 is connected to the gravity dust collector 9. A blast furnace downcomer insulation device is provided on the downcomer 4 to achieve insulation of the downcomer 4.

[0033] Example 1: Thermal insulation device using distributed temperature-sensing optical fibers

[0034] In this embodiment, the heat insulation device of the blast furnace downcomer 4 uses distributed temperature sensing optical fiber as temperature measuring device 6 to achieve comprehensive real-time monitoring of the wall temperature of the downcomer 4.

[0035] 1. Fabrication of thermal insulation structure 5

[0036] On the outside of the blast furnace downcomer 4, structural steel is welded along the axial and transverse directions of the downcomer 4 to form a robust skeleton structure.

[0037] Color-coated steel plates are selected as corrosion-resistant materials and are sealed and welded to the frame to form a sealed cavity that completely encloses the downcomer 4, ensuring that the gas will not leak.

[0038] 2. Installation of temperature alarm system

[0039] Inside the insulation structure 5, distributed temperature-sensing optical fibers 6 are laid along the axis of the downcomer 4. To ensure full coverage of temperature changes in the pipe wall, six temperature-sensing optical fibers are evenly arranged in the circumferential direction of the downcomer 4.

[0040] The temperature-sensing optical fiber extends from the bottom sealing plate of the insulation structure 5, connects to the optical fiber box 7, and then transmits the temperature signal to the temperature measurement and alarm control system 8 through the communication optical fiber.

[0041] The temperature measurement and alarm control system 8 is set with a temperature measurement point every 1 meter to collect pipe wall temperature data in real time. When the temperature at any measurement point exceeds 250℃ (which can be set to a specified value as needed), the system will issue an audible and visual alarm to prompt production personnel to adjust the blast furnace top gas temperature in a timely manner or to inspect and repair the downcomer pipe 4.

[0042] 3. Configuration of inflation and deflation systems

[0043] An inflation valve 11 is installed on the bottom sealing plate of the insulation structure 5 and connected to an inflation air source 10. In this embodiment, low-pressure air is selected as the inflation air source, which has the advantages of low cost and easy availability.

[0044] A vent valve 13 and a pressure transmitter 12 are installed on the top sealing plate of the insulation structure 5. The pressure transmitter 12 is located between the vent valve 13 and the sealed cavity and is used to monitor the pressure changes in the cavity in real time.

[0045] 4. Installation and commissioning of the device

[0046] After the device is installed, open the top vent valve 13 and the bottom inflation valve 11, and purge the sealed cavity with the inflation air source 10 to remove internal impurities and residual gas.

[0047] After purging, close the vent valve 13 and continue to fill the sealed cavity with low-pressure air through the inflation valve 11 until the pressure reaches 30 kPa. Then close the inflation valve 11.

[0048] Use pressure transmitter 12 to observe the pressure change inside the cavity. If there is no significant pressure drop within 24 hours, it indicates that the sealing is good. If a pressure drop is found, check whether there are any leaks at the welds or connections. After repair, repeat the sealing test.

[0049] After the sealing test is passed, the pressure inside the cavity is maintained at 30 kPa, and the device can be put into use.

[0050] During the blast furnace production process, pressure transmitter 12 monitors the cavity pressure in real time;

[0051] If the pressure drops to 0 kPa, it indicates that there may be a leak in the insulation structure 5, and the machine needs to be shut down for inspection and repair.

[0052] If the pressure rises to near the pressure at the top of the blast furnace, the analysis of the temperature-sensing fiber optic data will determine whether there is a gas leak in downcomer 4, and the leak point will be located and dealt with.

[0053] Example 2: Thermal insulation device using patch thermocouples

[0054] In this embodiment, the heat insulation device of the blast furnace downcomer 4 uses a patch thermocouple as a temperature measuring device 6 to achieve accurate local monitoring of the wall temperature of the downcomer 4.

[0055] 1. Fabrication of thermal insulation structure 5

[0056] Similar to Example 1, a skeleton is formed by welding steel profiles along the axial and transverse directions to the outside of the downcomer 4.

[0057] Galvanized steel sheet is selected as the corrosion-resistant material and is sealed and welded to the frame to form a complete sealed cavity.

[0058] 2. Installation of temperature alarm system

[0059] Inside the insulation structure 5, a set of patch thermocouples is installed every 2 meters along the axial direction of the downcomer 4 as a temperature measuring device 6. Each set includes 4 thermocouples, which are evenly distributed in the circumferential direction of the downcomer 4 wall to monitor temperature changes in different parts.

[0060] The thermocouple is led out from the bottom sealing plate of the insulation structure 5 through a high-temperature resistant wire, connected to the junction box, and then connected to the temperature measurement and alarm control system 8.

[0061] The temperature alarm control system 8 collects temperature data from each thermocouple in real time. When the temperature measured by any thermocouple exceeds 200℃, the system issues an alarm signal to remind production personnel to check the status of the downcomer 4 or adjust the blast furnace operating parameters.

[0062] 3. Configuration of inflation and deflation systems

[0063] An inflation valve 11 is installed on the bottom sealing plate of the insulation structure 5 and connected to an inflation gas source 10. In this embodiment, low-pressure nitrogen is selected as the inflation gas source to improve the safety of the device in high-temperature environments.

[0064] A vent valve 13 and a pressure transmitter 12 are installed on the top sealing plate. The pressure transmitter 12 is used to monitor the pressure inside the sealed cavity in real time.

[0065] 4. Installation and commissioning of the device

[0066] After the device is installed, open the venting valve 13 and the inflation valve 11, and use the inflation air source 10 to purge the sealed cavity to ensure that the inside is clean.

[0067] After purging, close the vent valve 13 and fill the cavity with low-pressure nitrogen through the inflation valve 11 until the pressure inside the cavity reaches 25 kPa. Then close the inflation valve 11.

[0068] Use pressure transmitter 12 to monitor pressure stability. If the pressure remains stable within 24 hours, the sealing is qualified. If the pressure drops, the leak needs to be investigated and repaired, and the test should be repeated.

[0069] After the sealing test is passed, the pressure inside the cavity is maintained at 25 kPa, and the device is put into use.

[0070] During blast furnace operation, pressure transmitter 12 monitors pressure changes in real time.

[0071] If the pressure drops abnormally, it indicates that there may be a leak in the insulation structure 5, which needs to be dealt with promptly.

[0072] If the pressure rises abnormally, combine the thermocouple temperature measurement data to determine whether there is a gas leak in downcomer 4, and take corresponding measures.

[0073] In the above embodiments, the gas filled in the sealed cavity, such as air or nitrogen, has a low thermal conductivity, which can effectively reduce heat transfer and achieve thermal insulation of the downcomer 4.

[0074] Durability: The insulation structure 5 is made of color-coated steel plate or galvanized steel plate, which has good corrosion resistance and can adapt to the high temperature and corrosive environment in blast furnace production.

[0075] Safety and Monitoring: The temperature alarm system monitors the temperature of the downcomer 4 in real time through distributed temperature-sensing optical fibers or patch thermocouples. Combined with the data analysis of the pressure transmitter 12, it not only improves the safety of the device, but also facilitates production personnel to adjust operating parameters or perform maintenance in a timely manner.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A heat insulation device for a blast furnace downcomer pipe, used for heat insulation of the downcomer pipe (4), characterized in that: It includes a heat insulation structure (5) and an air filling system. The heat insulation structure (5) is a sealed cavity fitted outside the blast furnace downcomer (4). The air filling system is connected to the sealed cavity and is used to fill the sealed cavity with gas to achieve heat insulation.

2. The blast furnace downcomer insulation device according to claim 1, characterized in that: It also includes a temperature alarm system, which includes a temperature measuring device (6) installed in the insulation structure (5) and a temperature alarm control system (8) connected to the temperature measuring device (6).

3. The blast furnace downcomer insulation device according to claim 2, characterized in that: The temperature measuring device (6) is a distributed temperature-sensing optical fiber or a patch thermocouple.

4. The blast furnace downcomer insulation device according to claim 3, characterized in that: The temperature measuring device (6) is laid axially along the wall of the downcomer (4) to monitor the wall temperature of the downcomer in real time.

5. The blast furnace downcomer insulation device according to claim 1, characterized in that: The insulation structure (5) near the top of the downcomer is provided with a vent valve (13) and a pressure transmitter (12) that connect to its sealed inner cavity, and the pressure transmitter (12) is arranged between the vent valve (13) and the sealed inner cavity to detect the pressure in the sealed cavity in real time.

6. The blast furnace downcomer insulation device according to claim 1, characterized in that: The insulation structure (5) is formed by welding steel sections along the axial and transverse directions of the downcomer pipe (4) to form a skeleton, and is sealed by welding corrosion-resistant steel plates onto the skeleton to form a sealed cavity.

7. The blast furnace downcomer insulation device according to claim 6, characterized in that: The corrosion-resistant steel plate is a color-coated steel plate or a galvanized steel plate.

8. The blast furnace downcomer insulation device according to claim 1, characterized in that: The inflation system includes an inflation source (10) connected to the sealed cavity and an inflation valve (11) arranged between the inflation source and the sealed cavity.

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