A high-power direct-current submerged arc furnace waste heat recovery device

Abstract

The application relates to a high-power direct-current electric arc furnace waste heat recovery device, which comprises an electric arc furnace and a waste heat boiler, and a group of rotary ash removal units are arranged at the lower side of the conical hopper-shaped furnace bottom of the waste heat boiler; the rotary ash removal unit is composed of a heating protective cover and a rotary ash removal mechanism, both of which are driven by a set of wind power systems, the wind power systems utilize the flow energy of the cooled flue gas in the exhaust pipe, do not need external motors, drive the heating protective cover to slowly rotate, and pass saturated steam into the jacket of the heating protective cover to uniformly supplement the heat of the furnace bottom and prevent coking; meanwhile, the dust removal rollers of the rotary ash removal mechanism are driven to circularly ascend and descend and roll along the surfaces of the heating protective cover and the rotary push block, and the accumulated ash can be effectively scraped off. The application combines rotary ash removal and uniform heating, solves the problems of the accumulated ash, coking and uneven heating of the furnace bottom of the waste heat boiler, significantly improves the heat exchange efficiency and power generation stability, and realizes the step-by-step utilization and energy-saving operation of energy.

Description

Technical Field

[0001] This invention relates to the field of electric arc furnace technology, specifically a waste heat recovery device for a high-power DC electric arc furnace. Background Technology

[0002] The high-power DC submerged arc furnace is an advanced metallurgical equipment employing a four-electrode structure and powered by DC power. Its core technology lies in achieving efficient smelting through high power density. Compared to traditional AC submerged arc furnaces, it converts AC power into stable DC power through thyristor rectification, eliminating the periodic zero-crossing and violent fluctuations of the AC arc. This allows the arc to form a continuous, concentrated, and extremely stable high-temperature zone within the furnace, significantly improving thermal efficiency and molten pool stirring. This characteristic not only allows the equipment to operate at higher power levels to greatly increase unit capacity but also effectively reduces electrode consumption, harmonic interference, and flicker. Furthermore, its deeper molten pool penetration promotes uniform reaction of the furnace charge, making it particularly suitable for producing high-purity ferroalloys, ferrochrome, and ferrosilicon. It demonstrates significant advantages in energy saving, environmental protection, and intelligent control.

[0003] The complete set of specialized equipment includes 1. a flue gas and waste heat recovery system; 2. a power generation system, etc. Among them, the flue gas and waste heat recovery system is the starting point and foundation of the entire project, responsible for the safe, efficient, and stable recovery of heat from the flue gas; the specialized waste heat boiler is the core equipment for waste heat recovery. Unlike ordinary boilers, the blast furnace waste heat boiler is specifically designed to address the characteristics of its flue gas: "high temperature, high dust, and easy scaling." Generally speaking, the key issues for the stable operation of waste heat recovery systems are ash accumulation and coking. Flue gas contains a large amount of fine metal oxides and coke powder, which adhere to the boiler heating surface, forming a layer of insulating ash. Some ash is in a molten state at high temperatures (especially low-melting-point metal compounds such as potassium and sodium), sticking to the heating surface in high-temperature areas like "syrup," forming hard, dense coke lumps. Since the ash layer and coke lumps are excellent insulation layers, the boiler cannot produce steam at the rated temperature and pressure, resulting in a sharp drop in power generation. Furthermore, the ash layer can absorb corrosive gases and cause localized corrosion when the heating surface wall temperature is low. Secondly, when the flue gas enters the bottom of the boiler, there is uneven flow distribution, which cannot heat the heating surface in a timely and sufficient manner, also affecting the heating efficiency to some extent. In view of the above problems, the present invention proposes a high-power DC submerged arc furnace waste heat recovery device. Summary of the Invention

[0004] The purpose of this invention is to provide a high-power DC submerged arc furnace waste heat recovery device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-power DC electric arc furnace waste heat recovery device, comprising an electric arc furnace and a waste heat boiler. The flue gas emission end of the electric arc furnace is connected to the high-temperature flue gas inlet of the waste heat boiler through a water-cooled flue. An exhaust pipe is provided on the top of the waste heat boiler. A waste heat boiler body is provided inside the waste heat boiler. A cone-shaped furnace bottom is connected to the bottom of the waste heat boiler body. A set of rotary ash removal units is provided in contact with the lower side of the furnace bottom. The rotary ash removal unit includes a heating protective cover that is rotated and fitted on the outside of the furnace bottom, and a rotary ash removal mechanism that lifts and scrapes the heating protective cover. The rotation power end of the heating protective cover, the rotation power end and the lifting power end of the rotary ash removal mechanism are connected to a set of wind power system. The wind power system provides rotation power through the flue gas flowing in the exhaust pipe.

[0006] Furthermore, the heating shield has the same shape as the furnace bottom and rotates to wrap around the outside of the furnace bottom, forming a jacketed heating chamber between the two; A fixed ring is fixedly installed on the outside of the connection between the furnace bottom and the waste heat boiler body. A rotating groove is opened inside the fixed ring, and a rotating ring is rotatably connected in the rotating groove. A driven gear ring is installed on the top of the rotating ring, and the bottom of the rotating ring is connected to the top of the heating protective cover. The driven gear ring is connected to the wind power system.

[0007] Furthermore, a medium inlet is provided on the jacketed heating chamber, and the gap of the jacketed heating chamber is 50mm-150mm.

[0008] Furthermore, the wind power system includes a power flue gas pipe installed on one side of the waste heat boiler body, and the power flue gas pipe is connected to the power flue gas inlet at the inlet end of the exhaust pipe through a return pipe; The internal rotating part of the power flue gas pipe is equipped with a fan wheel. The air inlet end of the fan wheel is provided with a tapering channel. The top of the fan wheel is connected to a drive shaft I. Drive shaft I is connected to drive shaft II through a drive belt I. The bottom of drive shaft II is connected to a drive gear and a rotating rod. The drive gear meshes with the driven gear ring. The rotating rod is connected to the rotating power end and the lifting power end of the rotary ash removal mechanism.

[0009] Furthermore, the rotary dust removal mechanism includes a frustum-shaped rotary pusher block located directly below the heating protective cover. A lifting rod is located at the center of the frustum-shaped rotary pusher block, and a circulating lifting component is connected to the bottom end of the lifting rod. A rotary power component is located on one side of the bottom of the frustum-shaped rotary pusher block. Both the circulating lifting component and the rotary power component are connected to the wind power system.

[0010] Furthermore, two inclined axles are symmetrically arranged on both sides between the heating shield and the frustum-shaped rotating push block. Dust removal rollers are installed at both ends of each axle. The dust removal rollers at both ends roll along the outer side of the corresponding heating shield and the outer side of the frustum-shaped rotating push block. A wheel sleeve is fitted on the axle, and a wheel sleeve axle is connected to the outer wall of the wheel sleeve. A connecting plate is rotatably connected to the end of the wheel sleeve axle. The two connecting plates are fixedly connected by a fixed connecting plate. The top of the lifting rod is fixedly connected to the bottom of the fixed connecting plate.

[0011] Furthermore, the circulating lifting assembly includes a connecting cap that is connected to the bottom end of the lifting rod via a connecting rod. A nut is connected to one side of the connecting cap via a connecting rod. A lead screw is threaded to the middle of the nut. A lead screw end shaft is installed at the bottom end of the lead screw. The lead screw end shaft is connected to the waste heat boiler via a bearing. The lead screw end shaft is connected to the wind power system via a transmission belt II.

[0012] Furthermore, the rotating power component includes a pulley fixed to the bottom of the frustum-shaped rotating pusher. The pulley is connected to the wind power system via a transmission belt III. A support groove is formed at the bottom of the frustum-shaped rotating pusher, and an arc-shaped support strip is slidably connected within the support groove.

[0013] Furthermore, the waste heat boiler corresponding to the high-temperature flue gas inlet is equipped with a gas collection chamber. A multi-stage filter screen is distributed on one side of the output end of the gas collection chamber. The top of the waste heat boiler body is connected to the exhaust pipe through the flue gas emission channel. A drying hood is installed on the top of the flue gas emission channel, and an expansion channel is provided at the connection between the drying hood and the exhaust pipe.

[0014] Furthermore, the bottom end of the exhaust pipe transmits gas outward through the exhaust port; a side-mounted flue gas outlet is provided around the waste heat boiler body, and the side-mounted flue gas outlet is connected to the flue gas emission channel.

[0015] Compared with the prior art, the beneficial effects of the present invention are: By using a rotary ash removal unit located on the outside of the furnace bottom, the residual pressure of the flue gas drives the heating protective cover to rotate and introduce saturated steam for uniform heating. Simultaneously, it drives the dust removal rollers to circulate and scrape ash. This effectively solves the problems of ash accumulation, coking, and uneven heating at the furnace bottom caused by high-temperature, high-dust flue gas from both physical removal and thermal compensation perspectives. It ensures the cleanliness and efficient heat exchange of the waste heat boiler's heating surface, thereby stabilizing the output of steam at rated parameters and increasing power generation. The entire ash removal and heating process is driven by the residual pressure of the flue gas, requiring no additional power equipment, resulting in energy savings and a simple control system. In addition, multi-stage filtration at the high-temperature flue gas inlet reduces impurity content at the source. Combined with the drying treatment in the flue gas emission channel, the system's operating environment is further optimized. The overall design is ingenious, the operation is reliable, and the energy-saving and environmental protection benefits are significant. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the distribution structure of the waste heat recovery device and waste heat boiler for a high-power DC submerged arc furnace.

[0017] Figure 2 This is an enlarged three-dimensional structural diagram of the rotary ash removal unit in this invention.

[0018] Figure 3 This is a partial cross-sectional view of the rotary dust removal unit in this invention.

[0019] Figure 4 This is a partial structural diagram of the bottom of the rotary dust removal unit in this invention.

[0020] Figure 5 This is a schematic diagram of the structure of the high-temperature flue gas inlet in this invention.

[0021] Figure 6 This is a schematic diagram of the structure of the circulating lifting component in this invention.

[0022] Figure 7 for Figure 1 A magnified structural diagram of A in the diagram.

[0023] Figure 8 for Figure 1 A magnified structural diagram of B in the diagram.

[0024] Figure 9 for Figure 3 A magnified structural diagram of C.

[0025] In the picture: 1. Mineral arc furnace, 2. Waste heat boiler, 3. Water-cooled flue, 4. Exhaust pipe, 40. Power flue gas inlet, 41. Flue gas diversion plate, 42. Discharge flue gas inlet. 5. Exhaust port; 6. Waste heat boiler body; 61. Furnace bottom; High-temperature flue gas inlet 7, gas collection chamber 70, multi-stage filter screen 71; Flue gas emission channel 8, drying hood 80, expansion channel 81; Rotary dust removal unit 9, power flue gas pipe 90, tapering channel 91, impeller 92, drive shaft I 93, drive belt I 94, drive shaft II 95, driving gear 96, driven gear ring 97, fixed ring 98, rotating ring 99, rotating groove 100, jacketed heating chamber 101, medium inlet 102, dust removal roller 103, wheel axle 104, wheel sleeve 105, wheel sleeve shaft 106, connecting plate 107, fixed connecting plate 108, lifting rod 109, frustum-shaped rotating push block 110, pulley 112, support slide groove 113, arc-shaped support slide bar 114, connecting cap 115, lead screw 116, nut 117, lead screw end shaft 118, drive belt II 119, rotating rod 120, drive belt III 121; Side-mounted flue gas outlet 10. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] Please see Figure 1This invention provides a high-power DC electric arc furnace waste heat recovery device, including an electric arc furnace 1 and a waste heat boiler 2. The flue gas emission end of the electric arc furnace 1 is connected to the high-temperature flue gas inlet 7 of the waste heat boiler 2 through a water-cooled flue duct 3. The top of the waste heat boiler 2 is connected to an exhaust pipe 4, and the bottom end of the exhaust pipe 4 is connected to an exhaust port 5 to transmit to the outside or subsequent environmental protection devices such as desulfurization and denitrification. The waste heat boiler body 6 is provided in the middle of the waste heat boiler 2. The bottom of the waste heat boiler body 6 is connected to a cone-shaped furnace bottom 61. The high-temperature flue gas input along the high-temperature flue gas inlet 7 contacts and diffuses from the bottom of the furnace bottom 61 to heat and utilize it. The top of the waste heat boiler body 6 is connected to the exhaust pipe 4 through a flue gas emission channel 8. At the same time, the flue gas passing through the bottom of the furnace bottom 61 continues to flow upward along the periphery of the waste heat boiler body 6 and flows into the flue gas emission channel 8 through the side flue gas outlet 10, and then continues to be transmitted and flowed outward. A set of rotary ash removal units 9 is installed on the lower side of the furnace bottom. The rotary ash removal unit 9 includes a heating protective cover that is rotated and fitted onto the outside of the furnace bottom 61, and a rotary ash removal mechanism that lifts and lowers the heating protective cover to scrape away ash. The rotation power end of the heating protective cover and the rotation and lifting power ends of the rotary ash removal mechanism are connected to a set of wind power system. The wind power system is powered by the flue gas flowing in the exhaust pipe 4, whose temperature has dropped to about 150℃-250℃, to form rotational kinetic energy. Then, this rotational power is transmitted to the rotation power end of the heating protective cover and the rotation and lifting power ends of the rotary ash removal mechanism to drive them to operate, realizing the effective utilization of the kinetic energy of the waste heat flow. No additional motor is required, which is energy-saving and simple to control. Specifically, such as Figure 2 , Figure 3 , Figure 9 As shown, the heating protective cover has the same shape as the furnace bottom 61 and rotates around the outside of the furnace bottom 61, forming a jacketed heating chamber 101 between the two. A fixing ring 98 is fixedly installed on the outside of the connection between the furnace bottom 61 and the waste heat boiler body 6. A rotating groove 100 with a cross-section of "+" is opened inside the fixing ring 98. A rotating ring 99 is rotatably connected inside the rotating groove 100. A driven gear ring 97 is installed on the top of the rotating ring 99, and the bottom is connected to the top of the heating protective cover downward. One side of the driven gear ring 97 is connected to the wind power system. That is, by operating the wind power system, the driven gear ring 97 is controlled to drive the rotating ring 99 to rotate in the rotating groove 100, thereby driving the heating protective cover to rotate slowly at a speed of 0.5-2 rpm outside the furnace bottom 61. The gap of the jacketed heating cavity 101 is controlled between 50mm and 150mm to ensure good heat transfer effect and structural strength. The jacketed heating cavity 101 is provided with a medium inlet 102. The heat homogenizing medium is introduced into the jacketed heating cavity 101 through the medium inlet 102. The heat homogenizing medium is saturated steam. After the steam enters the jacketed heating cavity 101, it will release the latent heat of vaporization through convection and condensation. The heat transfer coefficient is much higher than that of flue gas or air, forming a uniform temperature thermal enclosure to supplement the heating of the conical area.

[0031] The thermal shield is preferably made of SA-387 Gr11 CL2 chromium-molybdenum steel sheet by rolling and welding. This material has good high-temperature strength, creep resistance, and thermal conductivity, and can operate at temperatures above 600℃. Its manufacturing method includes: tapered blanking, hot rolling, longitudinal seam welding (using submerged arc welding), assembly and welding with the top flange and bottom ring, overall stress-relieving heat treatment, and finally machining to ensure dimensional and positional tolerances.

[0032] like Figure 1 , Figure 2 , Figure 4 , Figure 6 The rotary ash removal mechanism shown includes a frustum-shaped rotary pusher 110 placed directly below the heating protective cover. The frustum-shaped rotary pusher 110 coincides with the center of the bottom 61. A lifting rod 109 is provided at the center of the frustum-shaped rotary pusher 110. A circulating lifting component is connected to the bottom end of the lifting rod 109. A rotary power component is provided on one side of the bottom of the frustum-shaped rotary pusher 110 to drive the frustum-shaped rotary pusher 110 to rotate. Both the circulating lifting component and the rotary power component are connected to the wind power system. Two inclined, movable axles 104 are symmetrically arranged on both sides between the heating shield and the frustum-shaped rotating pusher 110. A dust-collecting roller 103 is installed at both ends of each axle 104. The dust-collecting rollers 103 roll along the outer sides of the corresponding heating shield and frustum-shaped rotating pusher 110. A wheel sleeve 105 is fitted onto the axle 104 located between the frustum-shaped rotating pusher 110 and the heating shield. The position of the wheel sleeve 105 relative to the wheel axle 104 remains unchanged. Wheel sleeve axles 106 are symmetrically connected to both sides of the outer wall of the middle part of the wheel sleeve 105. A connecting rod is rotatably connected to the end of the wheel sleeve axle 106. The connecting plate 107 is fixedly connected to the two connecting plates 107 by a fixed connecting plate 108, and the top of the lifting rod 109 is fixed to the bottom of the fixed connecting plate 108. By using the lifting of the lifting rod 109, the fixed connecting plate 108 at its end is driven to control the movement of the connecting plates 107 on both sides, thereby controlling the swing of the wheel sleeves 105 on both sides around the wheel sleeve shaft 106, thereby controlling the wheel shaft 104 to swing synchronously. While swinging, the dust removal rollers 103 at both ends of the wheel shaft 104 are kept moving on the corresponding heating protective cover and the outer wall of the frustum-shaped rotating push block 110, thereby performing the dust removal operation. The dust removal roller 103 is preferably made of silicon carbide ceramic, which has a Mohs hardness of up to 9.5 and exhibits extremely high wear resistance, high temperature resistance (>1600℃), and chemical stability. The outer surface of the roller can be machined with shallow teeth or spiral grooves to enhance scraping and dust guiding capabilities. Its manufacturing method involves isostatically pressing a silicon carbide blank, sintering it at high temperature, then precision grinding it to the specified dimensions and surface roughness (Ra≤1.6μm) with a diamond wheel, and finally assembling the bearings and axle.

[0033] Specifically, the circulating lifting assembly includes a connecting cap 115 connected to the bottom of the lifting rod 109 via a connecting rod. A nut 117 is connected to one side of the connecting cap 115 via a connecting rod. A lead screw 116 is threaded to the middle of the nut 117. A lead screw end shaft 118 is installed at the bottom of the lead screw 116. The bottom of the lead screw end shaft 118 is connected to the waste heat boiler 2 via a bearing. The nut 117 is provided with a guide device to limit its rotation (for example, a slider is provided on the outside of the nut, which slides in a fixed vertical guide groove). That is, by driving the lead screw 116 to rotate, the nut 117 is controlled to circulate and lift along the lead screw 116. Then, under the connection of the connecting rod and the connecting cap 115, the lifting rod 109 is driven to circulate and lift. One side of the lead screw end shaft 118 is connected to the wind power system via a transmission belt II 119. The rotating power assembly includes a pulley 112 fixed around the lifting rod 109 at the bottom of the frustum-shaped rotating pusher 110. One side of the pulley 112 is connected to the wind power system via a transmission belt Ⅲ121. At the same time, a support groove 113 is formed at the bottom of the frustum-shaped rotating pusher 110. The vertical section of the support groove 113 is T-shaped. An arc-shaped support strip 114 is slidably connected to one side inside the support groove 113. The vertical section of the arc-shaped support strip 114 matches the support groove 113. Meanwhile, a support rod is connected to the bottom of 11 to stably support the rotation of the frustum-shaped rotating pusher 110.

[0034] like Figure 1 , Figure 7 , Figure 8 As shown, the wind power system includes a power flue gas pipe 90 installed on one side of the waste heat boiler body 6. The end of the power flue gas pipe 90 facing the outside of the waste heat boiler 2 is connected to a return pipe. The return pipe is connected upward to the inlet end of the exhaust channel 4 and is connected to a power flue gas inlet 40. The upper side of the power flue gas inlet 40 is divided into two paths by a flue gas diversion plate 41, namely the lower power flue gas inlet 40 and the upper exhaust flue gas inlet 42. The exhaust flue gas inlet 42 is used to directly discharge the flue gas in the waste heat boiler 2, and the power flue gas inlet 40 is used to reuse the flue gas. Inside the power flue gas pipe 90, there is a rotating impeller 92. The air inlet end of the impeller 92 is provided with a converging channel 91. The converging channel 91 pressurizes and accelerates the flue gas flowing to the impeller 92 to ensure that the impeller 92 is subjected to sufficient rotational thrust. After passing through the impeller 92, the flue gas is transmitted again to the tail of the exhaust pipe 4 through the connecting pipe and then transmitted outward. The top of the impeller 92 is connected to a drive shaft I 93. One side of the drive shaft I 93 is rotatably connected to a drive shaft II 95 via a drive belt I 94. The bottom of the drive shaft II 95 is connected to a shaft with a drive gear 96. The drive gear 96 meshes with a driven gear ring 97, thereby driving the driven gear ring 97 to rotate, thus driving the rotation of the heating protective cover. At the same time, the bottom of the drive gear 96 is connected to a rotating rod 120. The rotating rod 120 extends downward and is rotatably connected to a drive belt III 121 and a drive belt II 119 via a pulley 112, thereby driving the rotation of the frustum-shaped rotating push block 110 and the lead screw 116, and thus driving the lifting rod 109 to rise and fall. The impeller 92 is a multi-bladed axial or centrifugal turbine. The cross-sectional shrinkage ratio (inlet area / throat area) of the tapered channel 91 is designed to be 2:1 to 4:1, which pressurizes and accelerates the flue gas flowing to the impeller 92, ensuring that sufficient rotational thrust is applied to the blades of the impeller 92.

[0035] It should be noted that the aforementioned power flue gas pipe 90, converging channel 91, impeller 92, drive shaft I 93, drive belt I 94, and drive shaft II 95 are all equipped with corresponding sealing structures to maintain stable and efficient gas transmission and ensure smooth power conversion. For detailed sealing structures and installation requirements, please refer to existing technologies, which will not be elaborated here. For example, the sealing at the rotating ring 99: A graphite packing sealing ring is set at the mating surface of the "+" groove between the fixed ring 98 and the rotating ring 99, and equipped with a pressure cap to adjust the sealing pressure, so as to prevent steam leakage in the jacket and external flue gas intrusion.

[0036] Drive shaft seals: High-temperature mechanical seals or magnetic seals are installed at all drive shafts that pass through the boiler wall or chamber (such as drive shaft I 93, drive shaft II 95, rotating rod 120, etc.) to ensure the reliability of dynamic seals at rotating parts and prevent flue gas leakage.

[0037] Jacketed heating chamber 101 sealing: The upper and lower ends between the heating protective cover and the furnace bottom 61 are statically sealed with metal spiral wound gaskets.

[0038] Power flue gas pipeline sealing: Metal toothed gaskets are used to seal the flange connections of each pipeline.

[0039] Preferred, such as Figure 5As shown, the waste heat boiler 2 corresponding to the high temperature flue gas inlet 7 is provided with a gas collection chamber 70. A multi-stage filter screen 71 is distributed on one side of the output end of the gas collection chamber 70. The high temperature flue gas is filtered by the multi-stage filter screen 71 to reduce the impurity content in the flue gas and reduce the amount of impurities adhering to the bottom of the furnace bottom 61. Specifically, the multi-stage filter 71 consists of three stages: the first stage is a high-temperature resistant stainless steel large-aperture grille to intercept large pieces of debris; the second stage is a ceramic fiber filter to filter medium-sized particles; and the third stage is a sintered metal wire mesh felt to filter fine dust. By performing preliminary filtration of the input high-temperature flue gas through the multi-stage filter 71, the impurity content in the flue gas can be significantly reduced, thereby reducing the amount of impurities adhering to the bottom of the furnace 61 and the heating protective cover at the source.

[0040] The top of the flue gas emission channel 8 is equipped with a drying hood 80, which dries the flue gas to be output to prevent moisture from affecting the subsequent reuse of flue gas or the pollution of emissions. At the same time, an extension channel 81 is provided at the connection between the drying hood 80 and the exhaust pipe 4. The extension channel 81 is used to diffuse the dried gas, that is, to reduce the speed of gas transmission and facilitate the subsequent conversion of flue gas flow power. Preferably, the drying hood 80 is filled with alumina drying balls or silica gel desiccant, which can be replaced or regenerated periodically. It is used to dry the flue gas to be output, to prevent acid corrosion caused by condensation in subsequent pipelines or equipment due to high moisture content of the flue gas, and to prevent it from affecting the dynamic stability of flue gas recirculation. The drying hood 80 features a quick-opening flange structure for easy filling and replacement of the desiccant. Its shell is made of 316L stainless steel, with an inner wall coated with a corrosion-resistant coating.

[0041] As a preferred embodiment of the present invention, the inner wall of the water-cooled flue 3 can be lined with refractory castable and equipped with circulating water-cooled wall pipes to ensure that the flue gas exiting the furnace at a temperature as high as 1200℃-1400℃ can be safely reduced to the design inlet temperature of the waste heat boiler.

[0042] The working principle of this invention is as follows: all the driving components mentioned above, which refer to power elements, electrical components and adapted power supplies, are connected by wires. The electrical components are connected in sequence. The detailed connection methods are well known in the art. The following mainly introduces the working principle and process, and does not describe the electrical control. High-temperature flue gas input and preliminary treatment: The high-temperature flue gas generated by the electric arc furnace 1 first enters the water-cooled flue duct 3 and is initially cooled to the design inlet temperature of the waste heat boiler 2. Subsequently, the flue gas enters the gas collection chamber 70 inside the boiler through the high-temperature flue gas inlet 7, and is filtered step by step by multi-stage filters 71 to remove most of the large pieces of debris and fine dust carried in the flue gas, thereby reducing the ash content entering the heat exchange zone from the source.

[0043] Main heat exchange and flue gas diversion: The filtered high-temperature flue gas impacts the conical furnace bottom 61 at the bottom of the waste heat boiler body 6, heating it to generate steam and completing the main heat energy recovery. The flue gas, whose temperature has been significantly reduced after heat exchange, is divided into two paths: Most of the flue gas rises around the pot body 6 and enters the flue gas emission channel 8 through the side flue gas outlet 10.

[0044] At the top of the flue gas emission channel 8, the flue gas passes through the drying hood 80 for drying treatment to remove moisture and prevent corrosion of subsequent equipment.

[0045] The dried flue gas enters exhaust pipe 4, ready to be discharged or enter subsequent environmental protection devices.

[0046] Powered flue gas extraction and kinetic energy conversion: At the inlet end of the exhaust pipe 4, the flue gas diverter 41 separates a portion of the dry flue gas, whose temperature has been reduced to 150℃-250℃, and leads it out through the powered flue gas inlet 40. This portion of flue gas enters the powered flue gas pipe 90 through the return pipe.

[0047] The flue gas is pressurized and accelerated as it flows through the converging channel 91. The high-speed flue gas drives the impeller 92 to rotate, converting the kinetic energy of the flue gas into mechanical rotational kinetic energy. The low-temperature flue gas, after performing work, is finally guided back to the end of the main exhaust pipe 4 for convergence and discharge.

[0048] Power distribution and rotary dust removal system drive: The rotational power generated by the impeller 92 is transmitted to the drive shaft 95 through the drive shaft I 93 and the drive belt I 94.

[0049] Drive the heating shield to rotate: The driving gear 96 at the lower end of the transmission shaft II 95 drives the driven gear ring 97 that meshes with it to rotate, so that the rotating ring 99 fixed with the driven gear ring 97 rotates in the rotating groove 100 of the fixed ring 98, and finally drives the entire heating shield to rotate slowly around the furnace bottom 61 at a speed of 0.5-2 rpm.

[0050] Drive the rotary dust removal mechanism: The rotating rod 120 at the bottom of the transmission shaft II95 transmits power to both branches simultaneously; Rotating branch: The pulley 112 is driven to rotate by the transmission belt Ⅲ121, thereby causing the frustum-shaped rotating push block 110 to rotate around its center.

[0051] Lifting branch: Drives the lead screw 116 to rotate via the transmission belt Ⅱ119.

[0052] Uniform heating process: While the heating shield rotates, saturated steam is sent into the jacketed heating chamber 101 through the medium inlet 102. The steam condenses and releases heat in the jacket, forming a uniform and stable high-temperature protective layer around the conical area of ​​the furnace bottom 61, which continuously heats the furnace bottom and effectively prevents molten ash from coking and sticking due to local low temperature.

[0053] Automatic cyclic scraping process: Lifting motion: The rotating lead screw 116 drives the nut 117 to perform a cyclic up-and-down linear motion. The nut 117 drives the lifting rod 109 to perform a synchronous cyclic lifting motion through the connecting rod and connecting cap 115.

[0054] Dust scraping execution: The lifting motion of the lifting rod 109 is converted into the periodic oscillation of two axles 104 through the fixed connecting plate 108, connecting plate 107, and wheel sleeve axle 106 at the top. During the oscillation, the dust removal rollers 103 installed at both ends of the axles 104 are in close contact with the outer wall of the rotating heating protective cover at one end and in close contact with the inclined surface of the rotating frustum-shaped rotating push block 110 at the other end, thus achieving rolling scraping.

[0055] The rotational movement of the heating shield and the frustum-shaped rotating pusher 110, combined with the lifting and oscillating motion of the dust removal roller 103, enables the ash scraping action to cover all areas of the entire conical heating surface, effectively removing the ash layer adhering to the surface. The scraped-off ash falls into the bottom of the cone hopper 61 of the furnace bottom and is discharged periodically.

[0056] It should be understood that in this invention, all rotating, sliding, meshing, belt-driven and other moving parts are well lubricated and not prone to slippage or wear, and each part is provided with a corresponding protective shell. However, in the accompanying drawings of this invention, the connection state of each moving part is not shown. It should also be understood that each part in this invention is made of metal or plastic material with suitable strength in the relevant field to ensure that its structural rigidity meets the actual requirements.

[0057] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high-power DC electric arc furnace waste heat recovery device, comprising an electric arc furnace (1) and a waste heat boiler (2), wherein the flue gas emission end of the electric arc furnace (1) is connected to the high-temperature flue gas inlet (7) of the waste heat boiler (2) through a water-cooled flue (3), an exhaust pipe (4) is provided on the top of the waste heat boiler (2), a waste heat boiler body (6) is provided inside the waste heat boiler (2), and a conical furnace bottom (61) is connected to the bottom of the waste heat boiler body (6), characterized in that, A set of rotary ash removal units (9) is provided on the lower side of the furnace bottom (61). The rotary ash removal unit (9) includes a heating protective cover that is rotated and fitted on the outside of the furnace bottom (61), and a rotary ash removal mechanism that lifts and scrapes the heating protective cover. The rotary power end of the heating protective cover is connected to a set of wind power system together with the rotary power end and the lifting power end of the rotary ash removal mechanism. The wind power system provides rotational power through the flue gas flowing in the exhaust pipe (4).

2. The high-power DC submerged arc furnace waste heat recovery device according to claim 1, characterized in that, The heating shield has the same shape as the furnace bottom (61) and rotates to wrap around the outside of the furnace bottom (61), forming a jacketed heating chamber (101) between the two. A fixing ring (98) is fixedly installed on the outside of the connection between the furnace bottom (61) and the waste heat boiler body (6). A rotating groove (100) is opened inside the fixing ring (98). A rotating ring (99) is rotatably connected inside the rotating groove (100). A driven gear ring (97) is installed on the top of the rotating ring (99). The bottom of the rotating ring (99) is connected to the top of the heating protective cover. The driven gear ring (97) is connected to the wind power system.

3. The high-power DC submerged arc furnace waste heat recovery device according to claim 2, characterized in that, The jacketed heating chamber (101) has a medium inlet (102) and the gap of the jacketed heating chamber (101) is 50mm-150mm.

4. The high-power DC submerged arc furnace waste heat recovery device according to claim 2, characterized in that, The wind power system includes a power flue gas pipe (90) installed on one side of the waste heat boiler body (6), and the power flue gas pipe (90) is connected to the power flue gas inlet (40) at the inlet end of the exhaust pipe (4) through a return pipe; The internal rotating part of the power flue gas pipe (90) is equipped with a fan (92). The air inlet end of the fan (92) is provided with a tapered channel (91). The top of the fan (92) is connected to a drive shaft I (93). The drive shaft I (93) is connected to the drive shaft II (95) through a drive belt I (94). The bottom of the drive shaft II (95) is connected to a drive gear (96) and a rotating rod (120). The drive gear (96) meshes with the driven gear ring (97). The rotating rod (120) is connected to the rotating power end and the lifting power end of the rotating ash removal mechanism.

5. The high-power DC submerged arc furnace waste heat recovery device according to claim 1, characterized in that, The rotating ash removal mechanism includes a frustum-shaped rotating pusher (110) located directly below the heating protective cover. A lifting rod (109) is provided at the center of the frustum-shaped rotating pusher (110). A circulating lifting component is connected to the bottom end of the lifting rod (109). A rotating power component is provided on one side of the bottom of the frustum-shaped rotating pusher (110). Both the circulating lifting component and the rotating power component are connected to the wind power system.

6. The high-power DC submerged arc furnace waste heat recovery device according to claim 5, characterized in that, Two inclined axles (104) are symmetrically arranged on both sides between the heating shield and the frustum-shaped rotating push block (110). Dust removal rollers (103) are installed at both ends of each axle (104). The dust removal rollers (103) at both ends roll along the outer side of the corresponding heating shield and the outer side of the frustum-shaped rotating push block (110). A wheel sleeve (105) is fitted on the axle (104). A wheel sleeve shaft (106) is connected to the outer wall of the wheel sleeve (105). A connecting plate (107) is rotatably connected to the end of the wheel sleeve shaft (106). The two connecting plates (107) are fixedly connected by a fixed connecting plate (108). The top of the lifting rod (109) is fixedly connected to the bottom of the fixed connecting plate (108).

7. The high-power DC submerged arc furnace waste heat recovery device according to claim 5, characterized in that, The circulating lifting assembly includes a connecting cap (115) connected to the bottom end of the lifting rod (109) via a connecting rod. A nut (117) is connected to one side of the connecting cap (115) via a connecting rod. A lead screw (116) is threaded to the middle of the nut (117). A lead screw end shaft (118) is installed at the bottom end of the lead screw (116). The lead screw end shaft (118) is connected to the waste heat boiler (2) via a bearing. The lead screw end shaft (118) is connected to the wind power system via a transmission belt II (119).

8. The high-power DC submerged arc furnace waste heat recovery device according to claim 5, characterized in that, The rotating power assembly includes a pulley (112) fixed at the bottom of the frustum-shaped rotating pusher (110). The pulley (112) is connected to the wind power system via a transmission belt III (121). A support groove (113) is provided at the bottom of the frustum-shaped rotating pusher (110). An arc-shaped support strip (114) is slidably connected in the support groove (113).

9. The high-power DC submerged arc furnace waste heat recovery device according to claim 1, characterized in that, The waste heat boiler (2) corresponding to the high-temperature flue gas inlet (7) is provided with a gas collection chamber (70). A multi-stage filter screen (71) is distributed on one side of the output end of the gas collection chamber (70). The top of the waste heat boiler body (6) is connected to the exhaust pipe (4) through the flue gas emission channel (8). A drying hood (80) is provided on the top of the flue gas emission channel (8). An expansion channel (81) is provided at the connection between the drying hood (80) and the exhaust pipe (4).

10. The high-power DC submerged arc furnace waste heat recovery device according to any one of claims 1 to 9, characterized in that, The bottom end of the exhaust pipe (4) transmits to the outside through the exhaust port (5); a side flue gas outlet (10) is provided around the body (6) of the waste heat boiler, and the side flue gas outlet (10) is connected to the flue gas emission channel (8).

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