Electromagnetic preheating equipment for blast furnace pulverized coal pipeline

Abstract

The invention relates to the field of blast furnace ironmaking, and particularly discloses electromagnetic preheating equipment for a blast furnace pulverized coal pipeline, which comprises a preheating pipe connected between a mixer and a blast furnace, the preheating pipe is made of a metal material, a plurality of channels for pulverized coal to pass through are arranged in the preheating pipe, and an electromagnetic heating coil is sleeved outside the preheating pipe. After alternating current is introduced into the electromagnetic heating coil, an alternating magnetic field is generated, the preheating pipe generates eddy current and then emits heat, heat is transferred to pulverized coal and nitrogen flowing in the pipeline, the temperature of the pulverized coal rises, and the purpose of preheating the pulverized coal is achieved. The electromagnetic heating coil generates eddy current in the metal preheating pipe to generate heat, so that non-contact heating is realized, and heat radiation loss and open fire hidden dangers of traditional resistance heating are avoided; the alternating magnetic field directly acts on the preheating pipe, and the heat efficiency is obviously higher than that of an indirect heating mode; heat is uniformly conducted to pulverized coal and nitrogen in the channel through the pipe wall, and local overheating or heating dead angles are avoided.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to an electromagnetic preheating device for blast furnace pulverized coal pipelines. Background Technology

[0002] Current status of pulverized coal injection technology in blast furnaces: In modern blast furnace ironmaking technology, pulverized coal injection technology has been widely used. Pulverized coal injection in blast furnaces is a mixture of anthracite and bituminous coal, which is then ground into powder by a medium-speed mill and loaded into an injection tank. After being pressurized and fluidized by gas, it is transported through pipelines to the tuyeres and injected into the blast furnace for combustion. This replaces part of the coke in providing physical heat and reducing agent, thereby reducing the coke ratio and the fuel cost per ton of iron.

[0003] Problems and drawbacks of existing technologies: Further increases in the pulverized coal injection ratio are limited; as the pulverized coal injection ratio increases, the coal-coke replacement ratio decreases, mainly due to the decrease in the burnout rate of the blast furnace; increasing the pulverized coal injection ratio will worsen the furnace conditions, as unburned pulverized coal will damage the permeability of the charge column, cause inactive accumulation in the hearth, and result in poor slag fluidity.

[0004] To address the aforementioned issues, prior art publication number CN119242874A discloses a blast furnace pulverized coal preheating system, including a pulverized coal injection workshop, a nitrogen heater, a conventional pulverized coal heater, a compressed nitrogen tank, a blast furnace, an oil storage tank and an expansion tank, a waste heat exchanger, a thermal oil pump, a PLC control system, and an audible and visual alarm device. This invention utilizes oil as a heat transfer medium and uses the waste heat of the blast furnace to heat the pulverized coal coming out of the pulverized coal injection workshop in the conventional pulverized coal heater. The heated pulverized coal then enters the blast furnace for combustion.

[0005] Existing preheating systems only offer systematic solutions, without providing specific details regarding preheating efficiency and uniformity. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] This invention provides an electromagnetic preheating device for blast furnace pulverized coal pipelines, which can solve the problem of low preheating efficiency in existing technologies. The specific solution is as follows: This invention provides an electromagnetic preheating device for pulverized coal pipelines in blast furnaces, comprising a preheating tube connected between a mixer and the blast furnace. The preheating tube is made of metal and has several through-holes at both ends for pulverized coal to pass through. An electromagnetic heating coil is sleeved on the outside of the preheating tube. When an alternating current is passed through the electromagnetic heating coil, an alternating magnetic field is generated, causing eddy currents in the preheating tube, which then heats up. The heat is transferred to the pulverized coal and nitrogen flowing inside the pipeline, raising the temperature of the pulverized coal and achieving the purpose of preheating it. By generating eddy currents in the metal preheating tube through the electromagnetic heating coil, non-contact heating is achieved, avoiding the heat radiation loss and open flame hazards of traditional resistance heating. The alternating magnetic field acts directly on the preheating tube, resulting in significantly higher thermal efficiency than indirect heating methods. Heat is evenly conducted through the tube wall to the pulverized coal and nitrogen in the channels, avoiding local overheating or heating dead zones. Combined with subsequent dynamic rotation to enhance heat exchange, the pulverized coal heats up quickly with low energy consumption, providing stable high-temperature pulverized coal for blast furnace injection, improving combustion efficiency, and reducing fuel waste caused by insufficient preheating, resulting in outstanding overall energy-saving effects.

[0008] Preferably, several channels are arranged in a spiral shape inside the preheating tube to increase the heat exchange time between the pulverized coal and the preheating tube. By designing the channels in a spiral shape, the inner wall surface area is significantly increased compared to straight channels, thus doubling the contact opportunities between the pulverized coal and the preheating tube. The spiral path extends the residence time of the pulverized coal in the channel, and with the centrifugal force of rotation, the pulverized coal is more easily dispersed and adheres to the tube wall, avoiding uneven heat exchange caused by clumping. The improved heat exchange efficiency not only accelerates the heating rate of the pulverized coal but also reduces the heating time required per unit of pulverized coal, indirectly reducing the operating load of the preheating tube, delaying the aging of the tube wall caused by long-term high temperature, and extending the service life of the equipment.

[0009] Preferably, the preheating pipe is inclined, with its inlet end higher than its outlet end. The inclined preheating pipe utilizes gravity to assist the flow of pulverized coal, reducing flow resistance. The rotation of the preheating pipe causes the pulverized coal to form a "fluidized" state in the channel, avoiding material accumulation in dead zones. The shaking mechanism uses a cam to periodically press the drive block, generating inertial force to shake off fine pulverized coal particles. These three factors work together to prevent blockage from the source. Compared with a static preheating pipe, this design significantly improves the continuity of pulverized coal flow, reduces the number of shutdowns for cleaning, and is especially suitable for pulverized coal with high humidity or fine particles, significantly reducing maintenance costs and the risk of production interruption.

[0010] Preferably, the preheating tube rotates along its own axis under the drive of the driving source, so that the pulverized coal at the inlet of the preheating tube can flow evenly into several channels, and the pulverized coal in each channel can fully contact the inner wall of the channel to achieve the purpose of rapid heat exchange.

[0011] Preferably, the preheating tube can rotate on the plumb surface passing through the central axis of the preheating tube under the drive source, thereby causing the preheating tube to vibrate and preventing coal dust from accumulating in the channel of the preheating tube.

[0012] Preferably, the feed end of the preheating tube is equipped with a scraper for bringing pulverized coal into the channel, and the scraper rotates relative to the preheating tube. The relative rotation design of the scraper and the preheating tube solves the problem of poor material flow caused by bridging and accumulation of pulverized coal in the feed tube. The two embodiments (fixed relative rotation and differential rotation) are adapted to different pulverized coal characteristics: the fixed structure is simple and reliable, and the differential rotation enhances the shearing force. Both can actively pick up the accumulated pulverized coal and guide it into the channel. The scraper blade is arc-shaped and fits the end of the preheating tube, which reduces wear and improves scraping efficiency, ensuring that pulverized coal continuously enters the channel, avoiding preheating interruption due to feed interruption, and ensuring the stable operation of the blast furnace injection system.

[0013] Preferably, a feed pipe and a discharge pipe are rotatably installed at both ends of the preheating pipe, and the feed pipe and the discharge pipe are connected to the mixer and the blast furnace respectively through flexible hoses.

[0014] Preferably, the scraper is fixed to the inner wall of the feed pipe, and the scraper rotates relative to the preheating pipe by the rotation of the preheating pipe.

[0015] Preferably, the scraper is rotatably connected to the side wall of the feed pipe, and the scraper rotates differentially with the preheating pipe under the drive of the drive source.

[0016] Preferably, a heat-conducting cavity is formed in the middle of the preheating pipe, and a heat-conducting roller is installed inside the heat-conducting cavity. The space between the outer wall of the heat-conducting roller and the inner wall of the heat-conducting cavity is filled with a heat-conducting medium. The heat-conducting roller has a cavity inside, which is distributed in a double-layer spiral shape inside the heat-conducting roller. Both ends of the cavity extend to the outer end of the heat-conducting roller and connect to the conveying pipe. Through the double-layer spiral cavity design of the heat-conducting roller, the temperature of the preheating pipe can be precisely controlled. Under heating conditions, the central area supplements heat to reduce the temperature difference of the pipe wall and improve the overall preheating uniformity. Under cooling conditions, it quickly responds to the risk of overheating and prevents the coal powder from coking and deteriorating. The filling of the heat-conducting medium enhances the heat conduction efficiency, making the temperature control response more sensitive. This not only ensures the quality of coal powder preheating but also avoids safety hazards caused by excessive temperature, thereby improving the intelligence level and operational reliability of the system.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention generates eddy currents in a metal preheating tube using an electromagnetic heating coil, achieving non-contact heating and avoiding the heat radiation loss and open flame hazards associated with traditional resistance heating. The alternating magnetic field acts directly on the preheating tube, resulting in significantly higher thermal efficiency than indirect heating methods. Heat is evenly conducted through the tube wall to the pulverized coal and nitrogen in the channel, preventing localized overheating or heating dead zones. Combined with subsequent dynamic rotation to enhance heat exchange, the pulverized coal heats up quickly with low energy consumption, providing stable high-temperature pulverized coal for blast furnace injection, improving combustion efficiency, and reducing fuel waste caused by insufficient preheating, resulting in outstanding overall energy-saving effects.

[0018] 2. This invention, by designing the channel in a spiral shape, significantly increases the inner wall surface area compared to a straight channel, thus doubling the contact opportunities between pulverized coal and the preheating tube. The spiral path extends the residence time of pulverized coal within the channel, and combined with the centrifugal force of rotation, the pulverized coal is more easily dispersed and adheres to the tube wall, avoiding uneven heat exchange caused by clumping. The improved heat exchange efficiency not only accelerates the heating rate of pulverized coal but also reduces the heating time required per unit of pulverized coal, indirectly reducing the operating load of the preheating tube, delaying the aging of the tube wall caused by long-term high temperatures, and extending the service life of the equipment.

[0019] 3. This invention utilizes gravity to assist the flow of pulverized coal by tilting the preheating tube, reducing flow resistance; the rotation of the tube causes the pulverized coal to form a "fluidized" state within the channel, avoiding material accumulation in dead zones; the shaking mechanism uses a cam to periodically press the drive block, generating inertial force to shake off fine pulverized coal particles. These three elements work together to prevent blockage at the source. Compared to static preheating tubes, this design significantly improves the continuity of pulverized coal flow, reduces the number of shutdowns for cleaning, and is especially suitable for high-humidity or fine-particle pulverized coal, significantly reducing maintenance costs and the risk of production interruption.

[0020] 4. This invention solves the problem of poor material feeding caused by bridging and accumulation of pulverized coal in the feed pipe through the relative rotation design of the scraper and the preheating tube. Two embodiments (fixed relative rotation and differential rotation) are adapted to different pulverized coal characteristics: the fixed structure is simple and reliable, while the differential rotation enhances the shearing force, both of which can actively pick up the accumulated pulverized coal and guide it into the channel. The scraper blade is arc-shaped and fits the end of the preheating tube, which reduces wear and improves scraping efficiency, ensuring that pulverized coal continuously enters the channel, avoiding preheating interruption due to feed interruption, and ensuring the stable operation of the blast furnace injection system.

[0021] 5. This invention achieves precise temperature control of the preheating pipe through the double-layer spiral cavity design of the heat-conducting roller and the dual-mode switching (heating furnace / radiator) of the conveying pipe. In heating mode, the central area supplements heat to reduce the temperature difference between the pipe walls and improve overall preheating uniformity. In cooling mode, it quickly responds to the risk of overheating, preventing coal powder from coking and deteriorating. The filling of the heat-conducting medium enhances heat transfer efficiency, making the temperature control response more sensitive. This ensures the quality of coal powder preheating while avoiding safety hazards caused by excessively high temperatures, thus improving the system's intelligence and operational reliability.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a system framework diagram of the preheating tube and blast furnace of the present invention; Figure 2 This is a front view of the preheating pipe of the present invention; Figure 3 This is a perspective view of the preheating tube of the present invention; Figure 4 This is a partial cross-sectional view of the preheating pipe of the present invention; Figure 5 This is a partial sectional view of the entire invention; Figure 6 This is a perspective view of the movable seat and the fixed seat of the present invention; Figure 7 This is an exploded view of the movable seat and the fixed seat of the present invention; Figure 8 This is an overall perspective view of the preheating pipe and the fixing base of the present invention; Figure 9 This is a perspective view of the cam and drive block of the present invention; Figure 10 This is a schematic diagram of the structure of the heat-conducting roller of the present invention.

[0024] The reference numerals in the attached figures are as follows: 1. Pulverized coal silo; 2. Pulverized coal injection tank; 3. Mixer; 4. Preheating pipe; 5. Electromagnetic heating coil; 6. Channel; 7. Feed pipe; 8. Discharge pipe; 9. Hose; 10. Scraper; 11. Scraper blade; 12. Movable seat; 13. Fixed seat; 14. Motor; 15. Drive shaft; 16. Drive gear; 17. Driven gear; 18. Hinge block; 19. Hinge groove; 20. Support block; 21. Drive block; 22. Cam; 23. Heat conduction cavity; 24. Heat conduction roller; 25. Cavity; 26. Conveying pipe; 27. Transmission wheel; 28. Transmission belt. Detailed Implementation

[0025] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0026] Example 1: As Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, this embodiment provides an electromagnetic preheating device for blast furnace pulverized coal pipelines, including a preheating pipe 4 connected between the mixer 3 and the blast furnace. As a prior art solution: pulverized coal in two pulverized coal bins 1 is fed into the mixer 3 through two injection tanks 2, and nitrogen is introduced into the two injection tanks 2 through a tank pressure regulating valve and a fluidization regulating valve. Nitrogen is also introduced into the mixer 3.

[0027] The preheating tube 4 is made of metal. An electromagnetic heating coil 5 is installed on the outside of the preheating tube 4. The inside of the preheating tube 4 has several channels 6 that are open at both ends and allow coal powder to pass through. When an alternating current is passed through the electromagnetic heating coil 5, an alternating magnetic field is generated, which causes eddy currents to be generated in the preheating tube 4 and heats up. The heat is transferred to the coal powder and nitrogen flowing in the channels 6, and the temperature of the coal powder rises, thus achieving the purpose of preheating the coal powder.

[0028] Example 2: The technical solution of this example differs from that of Example 1 in that, in order to increase the heat exchange area between the pulverized coal and the preheating tube 4, several channels 6 are spirally arranged inside the preheating tube 4 (not shown in the figure), thereby increasing the inner wall area of ​​the channels 6, which in turn increases the heat exchange area between the pulverized coal and the preheating tube 4, thereby making the pulverized coal heat up faster and improving the preheating efficiency.

[0029] Example 3: The technical solution of this example differs from that of Example 1 or Example 2 in that the preheating pipe 4 is inclined and its feed end is higher than its discharge end, thereby increasing the fluidity of pulverized coal and preventing it from being stuck in the channel 6 of the preheating pipe 4.

[0030] To further improve the preheating efficiency of the preheating tube 4, the preheating tube 4 can rotate axially along its own axis (the central axis of the preheating tube 4) under the drive source. This allows the pulverized coal at the inlet of the preheating tube 4 (the end connected to the mixer 3) to flow evenly into several channels 6, and allows the pulverized coal in each channel 6 to fully contact the inner wall of the channel 6, achieving rapid heat exchange. If the preheating tube 4 does not rotate, the pulverized coal can only contact the bottom of the inner wall of the channel 6, and cannot fully contact the inner wall of the channel 6 for heat exchange, resulting in heat waste.

[0031] In order to prevent coal dust from accumulating in the channel 6 of the preheating tube 4, the preheating tube 4 is rotated on the plumb surface passing through the central axis of the preheating tube 4 under the drive source, so that the preheating tube 4 vibrates, thus making it difficult for coal dust to accumulate in the channel 6.

[0032] like Figure 5 As shown, the preheating pipe 4 is rotatably installed with a feed pipe 7 and a discharge pipe 8 at both ends, and the feed pipe 7 and the discharge pipe 8 are connected to the mixer 3 and the blast furnace respectively through a hose 9.

[0033] The feed end of the preheating tube 4 is equipped with a scraper 10 for bringing coal powder into the channel 6. The scraper rotates relative to the preheating tube 4. A scraper blade 11 is fixedly connected to the outer wall of the scraper 10. The scraper blade 11 contacts the end of the preheating tube 4.

[0034] In one embodiment, the scraper 10 is fixedly connected to the inner wall of the feed pipe 7, and the scraper 10 rotates relative to the preheating pipe 4 by the rotation of the preheating pipe 4.

[0035] In another embodiment, the scraper 10 is rotatably connected to the side wall of the feed pipe 7. The scraper 10 rotates differentially with the preheating pipe 4 under the drive of the drive source, wherein the differential rotation includes differential rotation in the same direction and rotation in opposite directions.

[0036] In the above scheme, the scraper 10 and scraper blade 11 rotate relative to the preheating pipe 4, so that when the pulverized coal falls into the feed pipe 7, the pulverized coal accumulates at the bottom of the feed pipe 7. Therefore, the rotation of the scraper 10 can lift the pulverized coal, and then the pulverized coal is blown into the channel 6 through the tilting action and the blowing action of the injection tank 2, so as to exchange heat with the preheating pipe 4, thereby achieving the preheating effect of the pulverized coal.

[0037] The specific solution in this embodiment is as follows: like Figure 5 As shown, a movable seat 12 and a fixed seat 13 are installed below the preheating pipe 4. The two ends of the preheating pipe 4 are rotatably connected to the two ends of the movable seat 12. The fixed seat 13 can be fixed to the floor of the workshop. A motor 14 is fixedly connected to the middle of the movable seat 12. A drive shaft 15 is fixedly connected to the output end of the motor 14. A drive gear 16 is fixedly connected to the drive shaft 15. A driven gear 17 is fixedly connected to the middle of the preheating pipe 4. The driven gear 17 meshes with the drive gear 16. Thus, when the motor 14 starts, the driven gear 17 is driven to rotate through the drive gear 16, thereby driving the preheating pipe 4 to rotate.

[0038] like Figure 6 , Figure 7 As shown, a hinge block 18 is fixedly connected to one end of the bottom of the movable seat 12, and a hinge groove 19 is provided at the corresponding position of the fixed seat 13. The hinge block 18 is hinged to the hinge groove 19. A support block 20 is also fixedly connected to the fixed seat 13 to support the movable seat 12 and keep it in an inclined state.

[0039] like Figure 8 , Figure 9As shown, a drive block 21 is fixedly connected to the support block 20, and a cam 22 is fixedly connected to the drive shaft 15. The cam 22 can pass through the opening on the movable seat 12 and abut against the top of the drive block 21 from below the movable seat 12. With this scheme, when the drive shaft 15 rotates with the motor 14, the cam 22 also rotates synchronously. When the protrusion on the cam 22 abuts against the top of the drive block 21, it can drive the movable seat 12 to rotate around the hinge groove 19. When the protrusion on the cam 22 separates from the top of the drive block 21, the movable seat 12 returns to its original position. This reciprocating motion causes the preheating pipe 4 to rotate back and forth with the movable seat 12, thereby generating vibration and allowing the pulverized coal to flow smoothly in the channel 6, thus greatly reducing pulverized coal blockage and reducing downtime.

[0040] like Figure 8 As shown, the end of the scraper 10 and the end of the drive shaft 15 are connected to a drive wheel 27. The two drive wheels 27 are connected by a drive belt 28. The drive wheel 27 can be a pulley or a sprocket, and the drive belt 28 can be a belt or a chain.

[0041] Example 4: The technical solution in this example differs from the above examples in that, as follows... Figure 4 , Figure 10 As shown, a heat-conducting cavity 23 is provided in the middle of the preheating pipe 4. A heat-conducting roller 24 is installed inside the heat-conducting cavity 23. A heat-conducting medium is filled between the outer wall of the heat-conducting roller 24 and the inner wall of the heat-conducting cavity 23. A cavity 25 is provided inside the heat-conducting roller 24. The cavity 25 is distributed in a double-layer spiral shape inside the heat-conducting roller 24. Both ends of the cavity 25 extend to the outer end of the heat-conducting roller 24 and are connected to the conveying pipe 26. The conveying pipe 26 is connected to an external heating furnace or radiator and is used to convey the heat-conducting liquid.

[0042] It should be noted that the heat-conducting roller 24 in the above scheme can have two operating conditions: 1. Heating mode: The auxiliary preheating tube 4 is connected to the heating furnace and hot oil or other liquids in the heating furnace are transported through the conveying pipe 26 to heat the central part of the preheating tube 4, thereby further improving the preheating speed of the preheating tube 4.

[0043] 2. Cooling condition: When the temperature of the preheating pipe 4 exceeds the preset range, the conveying pipe 26 can be connected to the radiator to deliver the coolant to the heat-conducting roller 24, thereby rapidly cooling the preheating pipe 4 and preventing continuous heating from causing coal powder coking.

[0044] Working principle: S1. Pulverized coal conveying and premixing: Pulverized coal in pulverized coal silo 1 is conveyed alternately by two injection tanks 2. Nitrogen is introduced into injection tanks 2 through tank pressure regulating valve and fluidization regulating valve to fluidize the pulverized coal and send it into mixer 3. Nitrogen is also introduced into mixer 3. The mixed pulverized coal and nitrogen flow through pipeline into the feed end of preheating pipe 4.

[0045] S2. Electromagnetic heating basic mechanism: The preheating tube 4 is made of a metal magnetic material (such as carbon steel), and an electromagnetic heating coil 5 is tightly wrapped around it. When an alternating current is passed through the coil 5, a high-frequency alternating magnetic field is generated. The metal preheating tube 4 cuts the magnetic field lines, and the internal eddy current effect generates heat (Joule heating). The heat is conducted to the inside through the tube wall of the preheating tube 4. There are several channels 6 with two ends connected inside. When the coal powder and nitrogen flow through the channel 6, they directly contact the tube wall and are heated, realizing non-contact high-efficiency preheating.

[0046] S3. Dynamic Rotation Enhanced Heat Exchange: The rotation of the preheating tube 4 is driven by a motor 14. The motor 14 is fixed in the middle of the movable base 12, and its output end is connected to the drive shaft 15. A drive gear 16 is fixed on the drive shaft 15. A driven gear 17 is fixed in the middle of the preheating tube 4 and meshes with the drive gear 16. When the motor 14 starts, the drive gear 16 drives the driven gear 17 to rotate, causing the preheating tube 4 to rotate at a constant speed around its own central axis. During the rotation, the pulverized coal in the channel 6 is subjected to the combined action of centrifugal force and tube wall friction, tumbling from the bottom of the channel to all parts of the inner wall, avoiding uneven heat exchange caused by only contacting the bottom, and extending the residence time of the pulverized coal in the channel 6 to improve the fullness of heat exchange.

[0047] S4. Inclined Installation and Vibration to Prevent Blockage: The preheating pipe 4 is installed at an overall inclination (the feed end is higher than the discharge end), utilizing gravity to assist the flow of pulverized coal and reduce flow resistance. Its support structure includes a movable seat 12 and a fixed seat 13. The two ends of the movable seat 12 are rotatably connected to the two ends of the preheating pipe 4 via bearings, and a hinge block 18 is provided at one end of the bottom, which is hinged to the hinge groove 19 on the fixed seat 13. A support block 20 is provided on the fixed seat 13 to support the movable seat 12 and maintain its inclination angle. A cam 22 is also fixed on the drive shaft 15. When the cam 22 rotates with the shaft, its protruding part periodically presses against the drive block 21 on the support block 20, causing the movable seat 12 to swing at a small angle around the hinge groove 19 in the vertical plane, driving the preheating pipe 4 to vibrate synchronously. The inertial force generated by the vibration can shake off the fine pulverized coal particles attached to the inner wall of the channel 6, preventing them from accumulating and causing blockage. This is especially effective for pulverized coal with high humidity or fine particles.

[0048] S5. Optimized Feeding with Scraper: The feed end of the preheating pipe 4 is connected to the mixer 3 via the feed pipe 7, and the discharge end is connected to the blast furnace via the discharge pipe 8. Both pipes are flexibly connected to the preheating pipe 4 via flexible hoses 9 to accommodate the rotation and vibration of the preheating pipe 4. A scraper 10 is installed inside the feed pipe 7, its function being to guide the coal powder accumulated at the bottom of the feed pipe 7 into the channel 6. The scraper 10 has two implementations: ① It is fixedly connected to the inner wall of the feed pipe 7, rotating relative to the preheating pipe 4 as it rotates. The scraper blades 11 on the outer wall of the scraper 10 contact the end of the preheating pipe 4, and "scrape" the coal powder into the channel 6 when rotating; ② It is rotatably connected to the side wall of the feed pipe 7, rotating differentially with the preheating pipe 4 under the drive of an independent drive source (slow rotation in the same direction or rotation in opposite directions), using stronger shearing force to agitate the coal powder. Both methods can break the coal powder bridging phenomenon and ensure that the coal powder continuously enters the channel 6.

[0049] S6. Dual-condition heat-conducting roller temperature control adjustment: A heat-conducting cavity 23 is opened in the middle of the preheating pipe 4, and a heat-conducting roller 24 is installed inside; a high thermal conductivity medium (such as thermally conductive silicone grease) is filled between the outer wall of the heat-conducting roller 24 and the inner wall of the heat-conducting cavity 23 to enhance heat conduction; a double-layer spiral cavity 25 is opened inside the heat-conducting roller 24, extending to both ends of the roller body and connecting to the conveying pipe 26; the connection object of the conveying pipe 26 is switched according to the working condition requirements: ① Heating condition: The conveying pipe 26 is connected to an external heating furnace, and the heat medium (such as high-temperature hot oil) flows through the double-layer spiral cavity 25, and supplements the heat to the central area of ​​the preheating pipe 4 through the heat-conducting roller 24, making up for the temperature gradient caused by the rapid heat dissipation at the edge of the pipe wall due to rotation, so that the overall temperature field of the preheating pipe 4 is more uniform; ② Cooling mode: When the temperature sensor detects that the preheating pipe 4 is overheated (such as a sudden increase in the amount of spraying that leads to increased heat absorption), the delivery pipe 26 switches to the radiator, and the coolant (such as water or antifreeze) circulates through the cavity 25 to quickly remove excess heat and prevent the coal powder from pyrolysis and coking due to high temperature.

[0050] S7. Output after preheating: After the pulverized coal is preheated through channel 6, the temperature rises to the set range, and it enters the discharge pipe 8 from the discharge end of the preheating pipe 4. Then it is transported to the blast furnace injection system through the hose 9 to complete the entire preheating process.

[0051] In summary, eddy currents generated in the metal preheating tube 4 by the electromagnetic heating coil 5 achieve non-contact heating, avoiding the heat radiation loss and open flame hazards of traditional resistance heating. The alternating magnetic field acts directly on the preheating tube 4, resulting in significantly higher thermal efficiency than indirect heating methods. Heat is evenly conducted through the tube wall to the pulverized coal and nitrogen in the channel 6, avoiding local overheating or heating dead zones. Combined with subsequent dynamic rotation to enhance heat exchange, the pulverized coal heats up quickly with low energy consumption, providing stable high-temperature pulverized coal for blast furnace injection, improving combustion efficiency, and reducing fuel waste caused by insufficient preheating, resulting in outstanding overall energy-saving effects. By designing channel 6 as a spiral, the inner wall surface area is significantly increased compared to a straight channel, thus doubling the contact opportunities between pulverized coal and preheating tube 4. The spiral path extends the residence time of pulverized coal in channel 6, and combined with the centrifugal force of rotation, the pulverized coal is more easily dispersed and adheres to the tube wall, avoiding uneven heat exchange caused by agglomeration. The improved heat exchange efficiency not only accelerates the heating rate of pulverized coal but also reduces the heating time required per unit of pulverized coal, indirectly reducing the operating load of preheating tube 4, delaying the aging of the tube wall caused by long-term high temperature, and extending the service life of the equipment. The inclined setting of preheating tube 4 utilizes gravity to assist the flow of pulverized coal, reducing flow resistance; the rotation makes the pulverized coal form a "fluidized" state in channel 6, avoiding material accumulation in dead zones; the shaking mechanism uses cam 22 to periodically press the drive block 21, generating inertial force to shake off fine pulverized coal particles. These three factors work together to prevent blockage from the source. Compared to static preheating tubes, this design significantly improves the continuity of pulverized coal flow, reducing the number of shutdowns for cleaning, and is especially suitable for high humidity or fine-particle pulverized coal, significantly reducing maintenance costs and the risk of production interruption. The relative rotation design of the scraper 10 and scraper blade 11 solves the problem of poor material feeding caused by bridging and accumulation of pulverized coal in the feed pipe 7. Two implementation methods (fixed relative rotation and differential rotation) are adapted to different pulverized coal characteristics: the fixed structure is simple and reliable, while the differential rotation enhances the shearing force, both of which can actively pick up the accumulated pulverized coal and guide it into the channel 6. The scraper blade 11 is arc-shaped and fits against the end of the preheating pipe 4, reducing wear and improving scraping efficiency, ensuring that pulverized coal continuously enters the channel 6, avoiding preheating interruption due to feed interruption, and ensuring the stable operation of the blast furnace injection system. Through the double-layer spiral cavity 25 design of the heat-conducting roller 24, combined with the dual-mode switching (heating furnace / radiator) of the conveying pipe 26, precise control of the temperature of the preheating pipe 4 is achieved. In the heating mode, the central area supplements heat to reduce the temperature difference of the pipe wall and improve the overall preheating uniformity. In the cooling mode, it quickly responds to the risk of overheating and prevents the pulverized coal from coking and deteriorating. The use of heat-conducting medium enhances heat transfer efficiency and makes temperature control response more sensitive. This not only ensures the quality of pulverized coal preheating but also avoids safety hazards caused by excessive temperature, thereby improving the system's intelligence level and operational reliability.

[0052] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the present application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0054] Parallelism: The parallelism defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism. It allows for situations where the parallelism is not absolute due to factors such as assembly tolerance, design tolerance, and structural flatness. It also allows for errors within a small angular range, such as within 10 degrees of assembly error. These can all be considered as parallel relationships.

[0055] Perpendicularity: The perpendicularity defined in this application is not limited to an absolute perpendicular intersection (with an included angle of 90 degrees). It is permissible for non-absolute perpendicular intersections caused by factors such as assembly tolerances, design tolerances, and structural flatness. It is permissible for errors within a small angular range, such as an assembly error range of 80 to 100 degrees, which can all be understood as a perpendicular relationship.

[0056] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.

[0057] The devices or elements referred to in the embodiments of this application or implied herein must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of this application. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An electromagnetic preheating device for blast furnace pulverized coal pipelines, comprising a preheating pipe connected between a mixer and the blast furnace, characterized in that: The preheating tube is made of metal and has several channels through which pulverized coal passes. An electromagnetic heating coil is installed on the outside of the preheating tube. When an alternating current is passed through the electromagnetic heating coil, an alternating magnetic field is generated, which causes eddy currents in the preheating tube and heats up. The heat is transferred to the pulverized coal and nitrogen flowing in the tube, and the temperature of the pulverized coal rises, thus achieving the purpose of preheating the pulverized coal.

2. The electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: Several channels are spiral-shaped inside the preheating tube.

3. The electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: The preheating tube is set at an angle, with its inlet end higher than its outlet end.

4. The electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: The preheating tube rotates along its own axis under the drive of the driving source, so that the pulverized coal at the inlet of the preheating tube can flow evenly into several channels.

5. The electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: Driven by the driving source, the preheating tube can rotate on the plumb surface passing through the central axis of the preheating tube, thus causing the preheating tube to vibrate.

6. The electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: The feed end of the preheating tube is equipped with a scraper for carrying pulverized coal into the channel, and the scraper rotates relative to the preheating tube.

7. An electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 6, characterized in that: The preheating tube is rotatably equipped with a feed pipe and a discharge pipe at both ends, and the feed pipe and discharge pipe are connected to the mixer and the blast furnace respectively through flexible hoses.

8. An electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 7, characterized in that: The scraper is fixed to the inner wall of the feed pipe, and the scraper rotates relative to the preheating pipe due to the rotation of the preheating pipe.

9. An electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 7, characterized in that: The scraper is rotatably connected to the side wall of the feed pipe, and the scraper rotates differentially with the preheating pipe under the drive of the drive source.

10. An electromagnetic preheating device for pulverized coal pipelines in blast furnaces as described in claim 1, characterized in that: A heat-conducting cavity is provided in the middle of the preheating pipe. A heat-conducting roller is installed inside the heat-conducting cavity. A heat-conducting medium is filled between the outer wall of the heat-conducting roller and the inner wall of the heat-conducting cavity. A cavity is provided inside the heat-conducting roller. The cavity is distributed in a double-layer spiral shape inside the heat-conducting roller. Both ends of the cavity extend to the outer end of the heat-conducting roller and are connected to the conveying pipe.

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