Electric furnace waste heat recovery device

Abstract

The utility model discloses an electric furnace waste heat recovery device, including horizontal preheating device, scrap steel preheating feeding shaft, combustion settling chamber and vertical vaporization cooling flue, horizontal preheating device includes horizontal preheating fume hood and horizontal feeding groove, the top of scrap steel preheating feeding shaft has the shutter who can open and close, and the lower part side wall forms the feeding port and can extend into the second end of horizontal pass, and the upper part side wall still communicates with the top import of combustion settling chamber through the connecting channel, the top export of combustion settling chamber communicates with the bottom end of vertical vaporization cooling flue, be equipped with vaporization cooling pipe group in the wall surface of horizontal preheating fume hood, the groove wall of horizontal feeding groove, the side wall of scrap steel preheating feeding shaft, the side wall of connecting channel, the top wall and the upper part side wall of combustion settling chamber and the side wall of vertical vaporization cooling flue, and the electric furnace waste heat recovery device of the utility model can fully recover the waste heat of high-temperature flue gas produced in the process of electric furnace steelmaking, and reduces energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery from electric furnaces, and in particular to a waste heat recovery device for electric furnaces. Background Technology

[0002] Electric arc furnace steelmaking processes generate a large amount of high-temperature electric arc radiation and high-temperature flue gas. Fully recovering and utilizing the residual energy and heat in the high-temperature electric arc radiation and high-temperature flue gas has become an important measure for reducing costs and increasing efficiency in electric arc furnace steelmaking.

[0003] Currently, to accommodate the high-temperature radiation of the electric arc, the upper shell and furnace cover of electric arc furnaces employ a fully water-cooled structure. This structure requires a large amount of cooling water, resulting in a significant amount of heat being carried away by the cooling water and not being recovered!

[0004] Scrap steel preheating and coverless feeding technology is a key energy-saving, carbon-reducing, green, and efficient production technology for recovering waste heat from electric arc furnace steelmaking flue gas. Currently, horizontal continuous scrap steel preheating and feeding electric arc furnace technology is widely used due to its advantages of energy saving, environmental protection, high efficiency, and reliability. However, in this type of furnace, scrap steel is added to the furnace through a horizontal vibrating device, which is divided into a feeding section (without a cover) and a preheating section (with a cover).

[0005] In the feeding section, scrap steel is adsorbed by the scrap steel cross-sectional trolley disk and added to the horizontal vibration device. Driven by the horizontal vibration, the scrap steel enters the preheating section. In the preheating section, due to gravity, the scrap steel lies flat on the horizontal vibration device (bottom area of ​​the preheating section), while the high-temperature flue gas passes through the top of the preheating section. This results in insufficient convective heat exchange between the high temperature and the scrap steel, leading to poor preheating of the scrap steel. At the same time, the waste heat recovery rate of the high-temperature flue gas is low, resulting in insignificant energy-saving effects.

[0006] The fume hood in the horizontal scrap preheating section is an important component of the electric arc furnace, primarily used to collect and exhaust the high-temperature flue gas generated during the electric arc furnace smelting process. Traditional fume hoods mostly employ water cooling or refractory material structures, which have the following disadvantages:

[0007] (1) High energy consumption: Water-cooled fume hoods require a large amount of cooling water, resulting in high operating costs. (2) Easily damaged: High-temperature flue gas can easily cause local overheating of the water-cooled fume hood, leading to water pipe rupture and affecting production. (3) Low waste heat utilization rate: Water-cooled fume hoods cannot effectively recover waste heat from flue gas, resulting in energy waste. Utility Model Content

[0008] The purpose of this invention is to provide an electric furnace waste heat recovery device that can fully recover the waste heat of high-temperature flue gas generated during the electric furnace steelmaking process and reduce energy consumption.

[0009] The purpose of this utility model is achieved as follows: an electric furnace waste heat recovery device includes a horizontal preheating device, a scrap steel preheating and feeding shaft, a combustion settling chamber, and a vertical vaporization cooling flue. The horizontal preheating device includes a horizontal preheating hood and a horizontal feeding trough connected vertically, which enclose a horizontal channel. The first end of the horizontal channel is used to introduce electric furnace flue gas. The top of the scrap steel preheating and feeding shaft has an openable and closable gate. The lower side wall forms a feeding port that can extend into the second end of the horizontal channel. The upper side wall is also connected to the top inlet of the combustion settling chamber through a connecting channel. The top outlet of the combustion settling chamber is connected to the bottom end of the vertical vaporization cooling flue. Vaporization cooling pipe assemblies are provided in the wall of the horizontal preheating hood, the wall of the horizontal feeding trough, the side wall of the scrap steel preheating and feeding shaft, the side wall of the connecting channel, the top wall and upper side wall of the combustion settling chamber, and the side wall of the vertical vaporization cooling flue.

[0010] In a preferred embodiment of this utility model, a flue gas heating device is further provided in the combustion settling chamber. The flue gas heating device includes a solid heat storage body and an electric heating wire disposed in the solid heat storage body. A power supply device is provided outside the combustion settling chamber. The power supply device is connected to the electric heating wire. The solid heat storage body can store the heat energy converted by the electric heating wire and / or the heat of the electric furnace flue gas in the combustion settling chamber.

[0011] In a preferred embodiment of this utility model, the power supply device is also connected to a green power device, which generates electricity using photovoltaic or wind power.

[0012] In a preferred embodiment of the present invention, the solid heat storage body includes a plurality of magnesium oxide bricks stacked together.

[0013] In a preferred embodiment of the present invention, the electric furnace waste heat recovery device further includes an electric furnace device, the side wall of which is provided with a flue gas outlet, and the first end of the horizontal channel can extend into or out of the flue gas outlet.

[0014] In a preferred embodiment of this utility model, the horizontal feeding trough includes a movable feeding trough and a vaporization cooling feeding trough. The first end of the movable feeding trough can extend into or out of the flue gas outlet, and the second end of the movable feeding trough can be movably wrapped around the outside of the first end of the vaporization cooling feeding trough. A vaporization cooling pipe assembly is provided inside the wall of the vaporization cooling feeding trough, and the second end of the vaporization cooling feeding trough can be connected to the feeding port of the scrap steel preheating feeding shaft. A horizontal vibration device is also connected to the vaporization cooling feeding trough to transport the scrap steel from the second end of the horizontal feeding trough to the first end for feeding into the electric furnace device.

[0015] In a preferred embodiment of this utility model, the connecting channel includes a horizontal connecting channel and a vertical connecting channel, and a vaporization cooling pipe assembly is provided in both the horizontal connecting channel and the vertical connecting channel; the first end of the horizontal connecting channel is connected to the upper side wall of the scrap steel preheating and feeding shaft, the second end of the horizontal connecting channel is connected to the top side wall of the vertical connecting channel, and the bottom end of the vertical connecting channel is connected to the top inlet of the combustion settling chamber.

[0016] In a preferred embodiment of this utility model, the electric furnace waste heat recovery device further includes a steam drum. A main inlet pipe and a main outlet pipe are provided on the outer side of the horizontal preheating hood, the outer side of the horizontal feeding trough, the outer side of the scrap steel preheating feeding shaft, the outer side of the connecting channel, the outer side of the combustion settling chamber, and the outer side of the vertical vaporization cooling flue. The main inlet pipe and the main outlet pipe are connected to the corresponding vaporization cooling pipe group. The main outlet pipe is connected to the steam drum via a riser pipe to introduce the steam generated in the vaporization cooling pipe group into the steam drum. The steam drum is also connected to the main inlet pipe via a downcomer pipe to introduce the water separated from the steam drum into the vaporization cooling pipe group.

[0017] In a preferred embodiment of the present invention, each vaporization cooling pipe group includes at least one vaporization cooling pipe structure, the main water inlet pipe is connected to the corresponding vaporization cooling pipe structure through the corresponding water inlet branch pipe, and the main water outlet pipe is connected to the vaporization cooling pipe structure through the corresponding water outlet branch pipe.

[0018] In a preferred embodiment of the present invention, each group of vaporization cooling pipe structures includes vaporization cooling pipes arranged in a serpentine pattern, or each group of vaporization cooling pipe structures includes multiple vaporization cooling pipes arranged in parallel at intervals.

[0019] In a preferred embodiment of this utility model, a water replenishment device is also connected to the main water inlet pipes on the outside of the horizontal preheating fume hood, the outside of the horizontal feeding trough, and the outside of the scrap steel preheating feeding shaft. The water replenishment device includes a water tank, a water supply pump, a deaerator, and a circulation pump connected in sequence. The circulation pump is connected to the corresponding main water inlet pipe through corresponding pipelines.

[0020] In a preferred embodiment of this utility model, the top outlet of the vertical vaporization cooling flue is connected to a bag filter system; or the top outlet of the vertical vaporization cooling flue is connected to the flue inlet of the waste heat boiler, and the flue outlet of the waste heat boiler is connected to a bag filter system.

[0021] In a preferred embodiment of this utility model, an insulation layer is provided on the outside of the horizontal preheating hood, the scrap steel preheating and feeding shaft, the connecting channel, the combustion settling chamber, and the vertical vaporization cooling flue.

[0022] As described above, the electric furnace waste heat recovery device of this utility model is equipped with vaporization cooling pipe assemblies in the walls of the horizontal preheating hood, the horizontal feeding trough, the side walls of the scrap steel preheating feeding shaft, the connecting channel, the top and upper side walls of the combustion settling chamber, and the side walls of the vertical vaporization cooling flue. When the high-temperature flue gas generated by the electric furnace passes through, the water in the vaporization cooling pipe assembly can be heated into steam. By adopting vaporization cooling, compared with the existing water cooling, the waste heat in the high-temperature flue gas of the electric furnace can be recovered more effectively, reducing energy consumption, carbon emissions, and energy waste, making it more energy-efficient and environmentally friendly. Attached Figure Description

[0023] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the present invention. Wherein:

[0024] Figure 1 A schematic diagram of the structure of the electric furnace waste heat recovery device provided by this utility model.

[0025] Figure 2 for Figure 1 A partial structural diagram.

[0026] Figure 3 for Figure 2 In the sectional view of AA.

[0027] Figure 4 This is a schematic diagram of the combustion settling chamber provided by this utility model.

[0028] Figure 5 A schematic diagram of the combustion settling chamber and vertical vaporization cooling flue provided by this utility model.

[0029] Explanation of icon numbers:

[0030] 1. Electric furnace unit; 11. Flue gas outlet;

[0031] 2. Horizontal preheating device; 21. Horizontal preheating fume hood; 22. Horizontal feeding trough; 221. Movable material trough; 222. Movable trolley; 223. Vaporization cooling material trough; 224. Support frame;

[0032] 3. Scrap steel preheating and feeding shaft; 31. Gate; 32. Connecting channel; 321. Horizontal connecting channel; 322. Vertical connecting channel;

[0033] 4. Combustion settling chamber; 41. Flue gas reheating device; 411. Solid heat storage body; 412. Heating wire; 413. Busbar; 414. Water-cooled cable; 415. Power transmission line; 416. Power supply unit; 417. Power transmission line; 418. Green power generation unit; 4191. Photovoltaic; 4192. Wind power;

[0034] 5. Vertical vaporization cooling flue; 51. Horizontal flue; 52. Waste heat boiler; 53. Bag filter dust collection system;

[0035] 6. Steam drum; 61. Ascendant pipe; 62. Downcomer pipe;

[0036] 7. Vaporization cooling pipe assembly;

[0037] 8. Main water inlet pipe; 81. Fume hood water inlet branch pipe; 82. Material trough water inlet branch pipe;

[0038] 9. Main water outlet pipe; 91. Fume hood water outlet branch pipe; 92. Material trough water outlet branch pipe. Detailed Implementation

[0039] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described with reference to the accompanying drawings.

[0040] like Figures 1 to 5 As shown, this application provides an electric furnace waste heat recovery device, including a horizontal preheating device 2, a scrap steel preheating and feeding shaft 3, a combustion settling chamber 4, and a vertical vaporization cooling flue 5; the horizontal preheating device 2 includes a horizontal preheating hood 21 and a horizontal feeding trough 22 connected vertically, and the two enclose each other to form a horizontal channel, the first end of which is used to introduce electric furnace flue gas; the top of the scrap steel preheating and feeding shaft 3 has an openable and closable gate 31, and the lower side wall forms a feeding port that can extend into water. Inside the second end of the horizontal channel, the upper sidewall is also connected to the top inlet of the combustion settling chamber 4 via the connecting channel 32; the top outlet of the combustion settling chamber 4 is connected to the bottom end of the vertical vaporization cooling flue 5; vaporization cooling pipe groups 7 are provided in the wall of the horizontal preheating hood 21, the wall of the horizontal feeding trough 22, the sidewall of the scrap steel preheating feeding shaft 3, the sidewall of the connecting channel 32, the top wall and upper sidewall of the combustion settling chamber 4, and the sidewall of the vertical vaporization cooling flue 5.

[0041] Therefore, in this application, vaporization cooling pipe assemblies 7 are provided in the wall of the horizontal preheating hood 21, the wall of the horizontal feeding trough 22, the side wall of the scrap steel preheating feeding shaft 3, the side wall of the connecting channel 32, the top wall and upper side wall of the combustion settling chamber 4, and the side wall of the vertical vaporization cooling flue 5. When the high-temperature flue gas generated by the electric furnace device 1 passes through, the water in the vaporization cooling pipe assembly 7 can be heated into steam. By adopting the vaporization cooling method, compared with the existing water cooling, the waste heat in the high-temperature flue gas of the electric furnace can be recovered more effectively, reducing energy consumption, reducing carbon emissions, reducing energy waste, and making it more energy-saving and environmentally friendly.

[0042] Further optional, see Figure 4A flue gas heating device 41 is also provided in the combustion settling chamber 4. The flue gas heating device 41 includes a solid heat storage body 411 and an electric heating wire 412 installed in the solid heat storage body 411. A power supply device 416 is provided outside the combustion settling chamber 4. The power supply device 416 is connected to the electric heating wire 412. The solid heat storage body 411 can store the heat energy converted by the electric heating wire 412 and / or the heat of the electric furnace flue gas in the combustion settling chamber 4.

[0043] By installing a flue gas reheating device 41 based on solid heat storage in the combustion settling chamber 4, the flue gas in the low-temperature section of the electric furnace can be reheated to 750°C to meet the requirements for dioxin cracking in the flue gas after preheating scrap steel. At the same time, it can stabilize the temperature and pressure of the steam generated by the subsequent waste heat boiler 52 and improve the power generation efficiency of the steam.

[0044] In practical applications, the power supply unit 416 is also connected to a green energy unit 418, which utilizes photovoltaic power 4191 or wind power 4192 to generate electricity, thereby achieving green power generation. The solid heat storage body 411 comprises multiple stacked magnesium oxide bricks, specifically high-purity magnesium oxide. Of course, the solid heat storage body 411 can also use other heat storage media as needed; this embodiment is merely illustrative. (Refer to...) Figure 4 The green energy device 418 (e.g., a green energy microgrid) can be connected to the power supply device 416 (e.g., a flexible DC power supply device) via transmission line 417. A busbar 413 is provided on the solid heat storage body 411, and the busbar 413 is connected to each heating wire 412. The power supply device 416 is connected to the busbar 413 via transmission line 415 and water-cooled cable 414, which passes through the side wall of the combustion settling chamber 4.

[0045] The entire flue gas reheating device 41 operates in three processes, as follows:

[0046] The first process (heating process): The heating wire 412 inside the solid heat storage body 411 is energized by green electricity such as photovoltaic power 4191 or wind power 4192, converting electrical energy into heat energy, which is then stored in the solid heat storage body 411 through heat exchange. This mainly utilizes off-peak electricity or surplus wind power to heat the solid heat storage body 411, meeting the supplementary heating needs during periods of low temperature in the electric furnace smelting flue gas.

[0047] The second process (heat storage process): This is divided into two types of heat storage processes.

[0048] The first heat storage process: The heat generated by the heating wire 412 is continuously absorbed by the solid magnesium oxide brick, and the temperature of the solid heat storage body 411 continues to rise, from room temperature to above 850℃, and the heat storage process is completed.

[0049] The second type of heat storage process: When the flue gas temperature is higher than that of the solid heat storage body 411, the high-temperature flue gas continuously heats the solid magnesium oxide brick, and the temperature of the solid heat storage body 411 continuously rises, from room temperature up to above 850℃, and the heat storage process is completed.

[0050] Generally, an insulation layer can be installed on the outer wall of the combustion settling chamber 4. High-quality insulation materials can be used to make the high-temperature solid heat storage body 411 thermally insulated from the external environment, ensuring the high efficiency and energy saving of the heat storage system.

[0051] The third process (heat release process): When the temperature of the flue gas flowing through the combustion settling chamber 4 is lower than the temperature of the flue gas heating device 41, the flue gas heating device 41 will gradually release the heat of the solid heat storage body 411 to heat the flue gas, so that the temperature of the flue gas entering the waste heat boiler 52 can be basically stabilized at around 800℃.

[0052] By utilizing the flue gas heating device 41, the unstable wind and solar power are utilized, and the flue gas temperature entering the waste heat boiler 52 during different smelting stages of the electric furnace device 1 is stabilized, thereby improving the steam quality and corresponding power generation efficiency of the waste heat boiler 52.

[0053] Furthermore, refer to Figure 1 and Figure 2 The electric furnace waste heat recovery device also includes an electric furnace device 1, the side wall of which is provided with a flue gas outlet 11, and the first end of the horizontal channel can extend into or out of the flue gas outlet 11.

[0054] Specifically, the horizontal feeding trough 22 includes a movable feeding trough 221 and a vaporization cooling feeding trough 223. The first end of the movable feeding trough 221 can extend into or out of the flue gas outlet 11, and the second end of the movable feeding trough 221 can be movably wrapped around the outside of the first end of the vaporization cooling feeding trough 223. The vaporization cooling trough 223 is provided with a vaporization cooling pipe assembly 7 in the trough wall. The second end of the vaporization cooling feeding trough 223 can be connected to the feeding port of the scrap steel preheating feeding shaft 3. A horizontal vibration device is also connected to the vaporization cooling feeding trough 223 to transport the scrap steel from the second end of the horizontal feeding trough 22 to the first end for feeding into the electric furnace device 1.

[0055] When the first end of the aforementioned horizontal channel extends into the flue gas outlet 11, it should be sealed and inserted. Specifically, the first end of the movable material trough 221 can be sealed and inserted into the flue gas outlet 11 (a corresponding sealing structure can be set at the flue gas outlet 11), and the first end of the horizontal preheating hood 21 is connected to the side wall of the electric furnace device 1.

[0056] The movable material trough 221 and the vaporization cooling material trough 223 are elongated U-shaped trough structures with their openings facing upwards, arranged in the same horizontal direction. The bottom of the vaporization cooling material trough 223 can be supported by a support frame 224. The vaporization cooling material trough 223 is connected to a horizontal vibration device, which can be located at the second end of the vaporization cooling material trough 223. The aforementioned scrap steel preheating shaft is generally located on the side of the second end of the horizontal channel to avoid interference with the horizontal vibration device. The scrap steel added to the second end of the vaporization cooling material trough 223 through the preheated scrap steel shaft can move towards the first end of the vaporization cooling material trough 223 under the action of the horizontal vibration device, and then be added to the electric furnace device 1 via the movable material trough 221. The horizontal preheating hood 21 is a U-shaped groove structure with the groove opening facing downwards. Most of its sealing cover is set on the vaporization cooling material trough 223. Its second end is sealed and connected to the side wall of the scrap steel preheating feeding shaft 3. Its first end extends out of the first end of the vaporization cooling material trough 223 and is sealed and covered in the part of the movable material trough 221 located outside the flue gas outlet 11.

[0057] The movable material trough 221 can be fixed on the movable trolley 222. When it is necessary to pour out the molten steel in the electric furnace device 1, the movable trolley 222 is moved so that the first end of the movable material trough 221 is taken out from the flue gas outlet 11, and the electric furnace device 1 can be tilted so that the molten steel is poured out from the corresponding outlet of the electric furnace device 1.

[0058] Furthermore, the connecting channel 32 includes a horizontal connecting channel 321 and a vertical connecting channel 322. Both the horizontal connecting channel 321 and the vertical connecting channel 322 are equipped with vaporization cooling pipe groups 7. The first end of the horizontal connecting channel 321 is connected to the upper side wall of the scrap steel preheating and feeding shaft 3, the second end of the horizontal connecting channel 321 is connected to the top side wall of the vertical connecting channel 322, and the bottom end of the vertical connecting channel 322 is connected to the top inlet of the combustion settling chamber 4.

[0059] Furthermore, the electric furnace waste heat recovery device also includes a steam drum 6. A main water inlet pipe 8 and a main water outlet pipe 9 are provided on the outside of the horizontal preheating hood 21, the outside of the horizontal feeding trough 22, the outside of the scrap steel preheating feeding shaft 3, the outside of the connecting channel 32, the outside of the combustion settling chamber 4, and the outside of the vertical vaporization cooling flue 5. The main water inlet pipe 8 and the main water outlet pipe 9 are connected to the corresponding vaporization cooling pipe group 7. The main water outlet pipe 9 is connected to the steam drum 6 via a riser pipe 61 to introduce the steam generated in the vaporization cooling pipe group 7 into the steam drum 6. The steam drum 6 is also connected to the main water inlet pipe 8 via a downcomer pipe 62 to introduce the water separated from the steam drum 6 into the vaporization cooling pipe group 7.

[0060] Optionally, each vaporization cooling pipe group 7 includes at least one vaporization cooling pipe structure, the main water inlet pipe 8 is connected to the corresponding vaporization cooling pipe structure through the corresponding water inlet branch pipe, and the main water outlet pipe 9 is connected to the vaporization cooling pipe structure through the corresponding water outlet branch pipe.

[0061] Each vaporization cooling pipe group 7 typically includes multiple vaporization cooling pipe structures to improve vaporization cooling efficiency and better recover waste heat from flue gas. The arrangement of each vaporization cooling pipe structure can vary; for example, each group may include vaporization cooling pipes arranged in a serpentine pattern, or multiple vaporization cooling pipes arranged in parallel at intervals. Typically, the inlet main pipe 8 connects to the lower part of the vaporization cooling pipe group 7, and the outlet main pipe 9 connects to the upper part, allowing water to enter from the lower part and steam to exit from the upper part. The specific number of inlet main pipes 8 and outlet main pipes 9, the number of riser pipes 61 and downcomer pipes 62, the number of vaporization cooling pipe structures included in each vaporization cooling pipe group 7, and the arrangement of each vaporization cooling pipe structure are all determined according to actual needs. The vaporization cooling pipes can be constructed from pipes or channels divided by baffles or other partitions.

[0062] For example, in a specific case, refer to Figure 3 The horizontal preheating fume hood 21 and the horizontal feeding trough 22 share the same inlet manifold 8 and outlet manifold 9. The vaporization cooling pipe assembly 7 within the wall of the horizontal preheating fume hood 21 includes multiple sets of vaporization cooling pipe structures arranged along its horizontal length. Each set of vaporization cooling pipe structures includes a single vaporization cooling pipe arranged in a serpentine pattern, with the bends in the serpentine arrangement distributed at both ends of the vaporization cooling pipe along the length of the horizontal preheating fume hood 21. The vaporization cooling pipe assembly 7 within the wall of the horizontal feeding trough 22 also includes multiple sets of vaporization cooling pipe structures arranged along its horizontal length. Multiple baffles can be installed within the horizontal feeding trough 22 to divide and separate these multiple sets of vaporization cooling pipe structures.

[0063] The main water inlet pipe 8 is connected to multiple sets of vaporization cooling pipe structures within the horizontal preheating fume hood 21 via multiple fume hood water inlet branch pipes 81, and to multiple sets of vaporization cooling pipe structures within the horizontal feeding trough 22 via multiple material trough water inlet branch pipes 82. The main water outlet pipe 9 is connected to multiple sets of vaporization cooling pipe structures within the horizontal preheating fume hood 21 via multiple fume hood water outlet branch pipes 91, and to multiple sets of vaporization cooling pipe structures within the horizontal feeding trough 22 via multiple material trough water outlet branch pipes 92. Since the horizontal preheating fume hood 21 is stationary, while the vaporization cooling material trough 223 in the horizontal feeding trough 22 vibrates with the horizontal vibration device, the fume hood water inlet branch pipes 81 and 91 are both rigid pipes, while the material trough water inlet branch pipes 82 and 92 are both flexible pipes. The main water outlet pipe 9 is also connected to the steam drum 6 via multiple riser pipes 61, and the steam drum 6 is connected to the main water inlet pipe 8 via multiple downcomer pipes 62.

[0064] Taking the working principle of the vaporization cooling tube group 7 in the horizontal preheating hood 21 and the horizontal feeding trough 22 as an example, the high-temperature flue gas generated by the electric furnace device 1 enters the horizontal channel from the furnace chamber and exchanges heat with the water in the vaporization cooling tube group 7 in the horizontal preheating hood 21 and the vaporization cooling tube group 7 in the horizontal feeding trough 22. The water is heated and vaporized to generate steam. The steam enters the water outlet main pipe 9 and then enters the steam drum 6 through the riser pipe 61. Steam and water are separated in the steam drum 6. The separated steam is discharged through the steam collecting pipe on the steam drum 6 and can be used for power generation or heating. The separated water is then re-entered into the vaporization cooling tube group 7 in the horizontal preheating hood 21 and the vaporization cooling tube group 7 in the horizontal feeding trough 22 through the downcomer pipe 62 and the water inlet main pipe 8. This cycle repeats continuously.

[0065] For example, refer to Figure 1 and Figure 5 The vaporization cooling pipe assembly 7 inside the side wall of the vertical vaporization cooling flue 5 includes two sets of vaporization cooling pipe structures arranged vertically. Two main water inlet pipes 8 and two main water outlet pipes 9 are provided on the outer side of the vertical vaporization cooling flue 5. The main water inlet pipes 8 and the main water outlet pipes 9 can be annular pipes. One main water inlet pipe 8 and one main water outlet pipe 9 are respectively provided below and above each set of vaporization cooling pipe structures. Each set of vaporization cooling pipe structures includes vertically spaced pipes evenly distributed circumferentially. The lower end of each vertical pipe is connected to the main water inlet pipe 8, and the upper end of each vertical pipe is connected to the main water outlet pipe 9. The working principle of the vaporization cooling pipe assembly 7 in the vertical vaporization cooling flue 5 is similar to that in the horizontal preheating hood 21 and the horizontal feeding trough 22. The arrangement of vaporization cooling pipe groups 7 in the side wall of the scrap steel preheating and feeding shaft 3, the side wall of the connecting channel 32, the top wall and upper side wall of the combustion settling chamber 4, the connection of the water inlet main pipe 8 and the water outlet main pipe 9, and the working principle are similar to those in the vaporization cooling pipe groups 7 in the horizontal preheating fume hood 21 and the horizontal feeding trough 22, as well as the vaporization cooling pipe groups 7 in the vertical vaporization cooling flue 5, and will not be described in detail here.

[0066] Furthermore, a water supply device is connected to the main water inlet pipe 8 on the outside of the horizontal preheating fume hood 21, the outside of the horizontal feeding trough 22, and the outside of the scrap steel preheating feeding shaft 3. The water supply device includes a water tank, a water supply pump, a deaerator, and a circulation pump connected in sequence. The circulation pump is connected to the corresponding main water inlet pipe 8 through corresponding pipelines to supply water to the vaporization cooling pipe assembly 7.

[0067] Specifically, the makeup water tank is connected to the inlet of the deaerator via the first connecting pipe, the feed water pump is located on the first connecting pipe, the outlet of the deaerator is connected to each main water inlet pipe 8 via the second connecting pipe, and the circulation pump is located on the second connecting pipe. The specific number of the first connecting pipe, feed water pump, second connecting pipe, and circulation pump can be determined according to needs.

[0068] The aforementioned vaporization cooling pipe is made of high-temperature resistant and corrosion-resistant alloy steel pipe, which extends its service life.

[0069] Alternatively, an insulation layer may be provided on the outside of the horizontal preheating hood 21, the scrap steel preheating and feeding shaft 3, the connecting channel 32, the combustion settling chamber 4, and the vertical vaporization cooling flue 5 to reduce heat loss.

[0070] Alternatively, the height of the vertical vaporization cooling flue 5 shall not be less than 25m.

[0071] Alternatively, the steam drum 6 can also be connected to a heat accumulator via pipeline. The heat accumulator can store a large amount of steam in the steam drum 6, and the steam in the heat accumulator can be used for power generation.

[0072] Furthermore, since vaporization cooling pipe groups 7 are provided in the walls of the horizontal preheating hood 21, the horizontal feeding trough 22, the side walls of the scrap steel preheating feeding shaft 3, the side walls of the connecting channel 32, the top and upper side walls of the combustion settling chamber 4, and the side walls of the vertical vaporization cooling flue 5, and the vertical vaporization cooling flue 5 is relatively high, it can already achieve effective recovery of high-temperature flue gas preheating. Therefore, the top outlet of the vertical vaporization cooling flue 5 can be directly connected to the bag filter system via the horizontal flue 51, or, as needed, the top outlet of the vertical vaporization cooling flue 5 can be connected to the waste heat boiler 52 via the horizontal flue 51, and then connected to the bag filter system 53. In this case, the volume of the waste heat boiler 52 can be relatively small.

[0073] Taking the waste heat boiler 52 as an example, the working principle of the entire electric furnace waste heat recovery device is as follows:

[0074] Scrap steel is fed into the horizontal feeding trough 22 from the top of the scrap steel preheating and feeding shaft 3. Under the action of the horizontal vibration device, the scrap steel is conveyed from the second end to the first end of the horizontal feeding trough 22 to be fed into the electric furnace device 1. The high-temperature flue gas generated by the electric furnace device 1 (i.e., electric furnace flue gas) enters through the first end of the horizontal channel and exchanges heat with the scrap steel in the horizontal channel. Then, the high-temperature flue gas rises through the scrap steel preheating and feeding shaft 3 and enters the combustion settling chamber 4 through the connecting channel 32. The bottom 1 / 3 height of the four walls of the combustion settling chamber 4 is made of concrete wall structure, and the upper 2 / 3 height of the walls is made of vaporization cooling pipe group 7, which is used to further recover the waste heat of the flue gas and settle large particles of dust. The bottom of the combustion settling chamber 4 is equipped with an ash removal device, which can be used to periodically clean the settled dust. Subsequently, the flue gas enters the vertical vaporization cooling flue 5 to further recover waste heat and cause large particles of dust in the flue gas to fall into the combustion settling chamber 4, reducing the risk of blockage of the subsequent waste heat boiler 52. Finally, the flue gas enters the waste heat boiler 52 to further recover the waste heat of the flue gas (after the flue gas comes out of the vertical cooling flue, it enters the waste heat boiler 52 for further heat exchange to below 200°C, and after the flue gas is cooled to below 200°C in the preheating boiler, it enters the subsequent bag filter dust collection system 53).

[0075] As the high-temperature flue gas passes sequentially through the horizontal channel, the scrap steel preheating and feeding shaft 3, the connecting channel 32, the combustion settling chamber 4, and the vertical vaporization cooling flue 5, the heating in the corresponding vaporization cooling tube group 7 is vaporized to generate steam. The steam enters the water outlet main pipe 9 and then enters the steam drum 6 through the riser pipe 61. Steam-water separation is carried out in the steam drum 6, and the separated water re-enters the vaporization cooling tube group 7 through the downcomer pipe 62 and the water inlet main pipe 8 to form a cycle. The waste heat in the high-temperature flue gas can be effectively recovered by using each group of vaporization cooling tube groups 7.

[0076] In summary, the electric furnace waste heat recovery device of this embodiment has the following advantages:

[0077] (1) Energy saving and environmental protection: The vaporization cooling method is adopted. Vaporization cooling pipe groups 7 are installed in the wall of the horizontal preheating hood 21, the wall of the horizontal feeding trough 22, the side wall of the scrap steel preheating feeding shaft 3, the side wall of the connecting channel 32, the top wall and upper side wall of the combustion settling chamber 4, and the side wall of the vertical vaporization cooling flue 5. This can effectively recover the waste heat in the flue gas, with high waste heat utilization rate, reduced energy consumption, and reduced carbon emissions.

[0078] (2) Long service life: The vaporization cooling coil is made of high temperature and corrosion resistant alloy steel pipe, which extends the service life.

[0079] (3) Reduce the risk of blockage: The design of the combustion settling chamber 4 and the vertical vaporization cooling flue 5 can effectively settle large dust particles and reduce the risk of blockage of the subsequent waste heat boiler 52. The top outlet of the combustion settling chamber 4 is equipped with a vertical vaporization cooling flue 5 surrounded by partitioned vaporization cooling pipe groups 7. The inside of the flue is hollow and there are no other heat exchange panels. This can avoid the dust from blocking the heat exchange plates. The flue gas rises and exchanges heat in the vertical vaporization cooling flue 5 while the dust settles.

[0080] (4) Reasonable structure and easy maintenance: This technology has a reasonable structure, is easy to manufacture and install, and is easy to maintain.

[0081] The above are merely illustrative embodiments of this utility model and are not intended to limit the scope of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. A waste heat recovery device for an electric furnace, characterized in that, This includes a horizontal preheating device, a scrap steel preheating and feeding shaft, a combustion settling chamber, and a vertical vaporization cooling flue. The horizontal preheating device includes a horizontal preheating hood and a horizontal feeding trough connected vertically, which together form a horizontal channel. The first end of the horizontal channel is used to introduce electric furnace flue gas. The top of the scrap steel preheating feeding shaft has an openable and closable gate, and the lower side wall forms a feeding port that can extend into the second end of the horizontal channel. The upper side wall is also connected to the top inlet of the combustion settling chamber through a connecting channel. The top outlet of the combustion settling chamber is connected to the bottom end of the vertical vaporization cooling flue. Vaporization cooling pipe assemblies are provided inside the walls of the horizontal preheating hood, the horizontal feeding trough, the side walls of the scrap steel preheating feeding shaft, the side walls of the connecting channel, the top and upper side walls of the combustion settling chamber, and the side walls of the vertical vaporization cooling flue.

2. The electric furnace waste heat recovery device as described in claim 1, characterized in that, A flue gas heating device is also provided in the combustion settling chamber. The flue gas heating device includes a solid heat storage body and an electric heating wire disposed in the solid heat storage body. A power supply device is provided outside the combustion settling chamber. The power supply device is connected to the electric heating wire. The solid heat storage body can store the heat energy converted by the electric heating wire and / or the heat of the electric furnace flue gas in the combustion settling chamber.

3. The electric furnace waste heat recovery device as described in claim 2, characterized in that, The power supply device is also connected to a green energy device, which generates electricity using photovoltaic or wind power.

4. The electric furnace waste heat recovery device as described in claim 2, characterized in that, The solid heat storage body comprises multiple magnesium oxide bricks stacked together.

5. The electric furnace waste heat recovery device as described in claim 1, characterized in that, The electric furnace waste heat recovery device also includes an electric furnace device, the side wall of which is provided with a flue gas outlet, and the first end of the horizontal channel can extend into or out of the flue gas outlet.

6. The electric furnace waste heat recovery device as described in claim 5, characterized in that, The horizontal feeding trough includes a movable feeding trough and a vaporization cooling feeding trough. The first end of the movable feeding trough can extend into or out of the flue gas outlet. The second end of the movable feeding trough can be movably wrapped around the outside of the first end of the vaporization cooling feeding trough. The vaporization cooling pipe assembly is provided inside the wall of the vaporization cooling feeding trough. The second end of the vaporization cooling feeding trough can be connected to the feeding port of the scrap steel preheating feeding shaft. A horizontal vibration device is also connected to the vaporization cooling trough, which is used to transport scrap steel from the second end of the horizontal feeding trough to the first end, so as to add it into the electric furnace device.

7. The electric furnace waste heat recovery device as described in claim 1, characterized in that, The connecting channel includes a horizontal connecting channel and a vertical connecting channel, and the vaporization cooling pipe assembly is provided in both the horizontal connecting channel and the vertical connecting channel; the first end of the horizontal connecting channel is connected to the upper side wall of the scrap steel preheating and feeding shaft, the second end of the horizontal connecting channel is connected to the top side wall of the vertical connecting channel, and the bottom end of the vertical connecting channel is connected to the top inlet of the combustion settling chamber.

8. The electric furnace waste heat recovery device as described in claim 1, characterized in that, The electric furnace waste heat recovery device also includes a steam drum. A main water inlet pipe and a main water outlet pipe are provided on the outside of the horizontal preheating hood, the outside of the horizontal feeding trough, the outside of the scrap steel preheating feeding shaft, the outside of the connecting channel, the outside of the combustion settling chamber, and the outside of the vertical vaporization cooling flue. The main water inlet pipe and the main water outlet pipe are connected to the corresponding vaporization cooling pipe group. The outlet main pipe is connected to the steam drum via an ascender pipe to allow steam generated in the vaporization cooling pipe assembly to enter the steam drum; the steam drum is also connected to the inlet main pipe via a downcomer pipe to allow water separated from the steam drum to enter the vaporization cooling pipe assembly.

9. The electric furnace waste heat recovery device as described in claim 8, characterized in that, Each group of vaporization cooling pipes includes at least one vaporization cooling pipe structure. The main water inlet pipe is connected to the corresponding vaporization cooling pipe structure through a corresponding water inlet branch pipe, and the main water outlet pipe is connected to the vaporization cooling pipe structure through a corresponding water outlet branch pipe.

10. The electric furnace waste heat recovery device as described in claim 9, characterized in that, Each group of vaporization cooling pipe structures includes vaporization cooling pipes arranged in a serpentine pattern, or Each group of vaporization cooling pipe structures includes multiple vaporization cooling pipes arranged in parallel at intervals.

11. The electric furnace waste heat recovery device as described in claim 8, characterized in that, A water supply device is also connected to the main water inlet pipes outside the horizontal preheating fume hood, the horizontal feeding trough, and the scrap steel preheating feeding shaft. The water supply device includes a water tank, a water supply pump, a deaerator, and a circulation pump connected in sequence. The circulation pump is connected to the corresponding main water inlet pipe through corresponding pipelines.

12. The electric furnace waste heat recovery device as described in claim 1, characterized in that, The top outlet of the vertical vaporization cooling flue is connected to a bag filter system; or The top outlet of the vertical vaporization cooling flue is connected to the flue inlet of the waste heat boiler, and the flue outlet of the waste heat boiler is connected to the bag filter dust collection system.

13. The electric furnace waste heat recovery device as described in claim 1, characterized in that, An insulation layer is provided on the outside of the horizontal preheating hood, the scrap steel preheating and feeding shaft, the connecting channel, the combustion settling chamber, and the vertical vaporization cooling flue.

Images