An electric arc furnace flue gas waste heat recovery system

Abstract

The present invention relates to the field of flue gas recovery, and specifically to a waste heat recovery system for the flue gas of an electric arc furnace, which includes a treatment furnace. A smoke collecting hood located above the electric arc furnace is arranged on the side of the treatment furnace. A flue gas collecting unit is arranged on the smoke collecting hood. An pre-heat exchange unit capable of pre-treating heat is fixedly arranged on the upper part of the treatment furnace. A post-heat exchange unit capable of post-treating the flue gas is arranged on the lower part of the treatment furnace; the present invention can efficiently recover the heat in different temperature ranges in the flue gas, can also adjust the liquid temperature according to the real-time temperature to further improve the heat recovery efficiency, can effectively capture and concentrate the high-temperature flue gas, reduce the loss of flue gas, significantly improve the collection efficiency, ensure the full recovery of the waste heat of the flue gas, ensure the best heat exchange effect, and can also effectively separate the gas and the liquid, mix the harmful substances in the flue gas with the liquid, ensure that the discharged gas is clean, and overall improve the environmental protection and economic benefits of the system.

Description

Technical Field

[0001] The present invention relates to the field of flue gas recovery, and more specifically to a waste heat recovery system for the flue gas of an electric arc furnace. Background Art

[0002] An electric arc furnace (EAF) generates a large amount of high-temperature flue gas during the steel production process, and this flue gas contains abundant heat. However, traditional electric arc furnaces usually directly discharge this part of the flue gas into the atmosphere, which not only wastes valuable thermal energy resources but also increases the environmental burden.

[0003] The Chinese patent with the application number 201410215970.3 discloses an industrial electric arc furnace waste heat utilization and flue gas recovery device. A dust collection hood is arranged above the electric arc furnace, and the dust collection hood is connected to an exhaust pipeline provided with a dust removal mechanism. The dust removal mechanism is connected to an exhaust stack, and the exhaust stack discharges the flue gas into a waste heat furnace connected to the exhaust stack for waste heat recovery; the electric arc furnace is also connected to a combustion sedimentation chamber, the combustion sedimentation chamber is connected to a heat pipe evaporator, and the heat pipe evaporator is connected to a high-pressure steam drum to provide high-pressure steam for other equipment to use; this device collects flue gas through a dust collection hood arranged above the electric arc furnace for purification and waste heat recovery, and also sets a waste heat recovery device on the sedimentation chamber connected to the electric arc furnace, and uses two methods to simultaneously carry out waste heat recovery and purification treatment on the dust and flue gas, maximizing the heat utilization rate and being applicable to production.

[0004] The Chinese patent with the application number 200610088072.1 discloses an electric arc furnace internal exhaust gas cooling waste heat utilization and recovery system and its recovery method. It mainly uses a heat pipe steam generator connected to a combustion sedimentation chamber through a heat preservation pipeline. The heat pipe steam generator is connected to a dust collector, the dust collector is connected to a main fan, and the main fan is connected to an exhaust stack. The internal exhaust gas of the electric arc furnace is discharged, mixed with cold air through a water-cooled sliding sleeve and then enters the combustion sedimentation chamber. The flue gas coming out of the combustion sedimentation chamber enters the heat pipe steam generator directly through a heat preservation flue. The flue gas coming out of the heat pipe steam generator directly enters or is mixed with other flue gases and then enters the dust collector for dust removal, and is then pressed into the exhaust stack by the main fan and discharged into the atmosphere. The present invention can efficiently cool high-temperature flue gas, maximize the recovery of the heat energy in the flue gas, and improve the dust removal ability; it can reduce the system air volume and lower the operation cost; the heat pipe steam generator operates reliably and stably, meeting the requirements of normal production.

[0005] However, the following problems still exist in actual applications, specifically:

[0006] 1. The specific working conditions and flue gas characteristics of the electric arc furnace are not fully considered.

[0007] 2. The treatment of the flue gas temperature range is not delicate enough, it is difficult to adapt to the complex flue gas composition and temperature changes of the electric arc furnace, and it is impossible to adjust the liquid temperature according to the real-time temperature, affecting the heat exchange effect.

[0008] 3. The maintenance cost is relatively high and frequent manual intervention is required.

[0009] 4. There is a lack of an effective separation design for harmful substances in the flue gas, and the discharged gas still contains a certain amount of harmful substances, resulting in limited environmental protection performance.

[0010] Therefore, how to overcome the above-mentioned existing technical problems and defects has become the key problem to be solved. Summary of the Invention

[0011] The object of the present invention is to overcome the defects described in the background art, so as to realize an electric arc furnace flue gas waste heat recovery system. This system can efficiently recover the heat in different temperature ranges of the flue gas, can also adjust the liquid temperature according to the real-time temperature to further improve the heat recovery efficiency, can effectively capture and concentrate the high-temperature flue gas, reduce the loss of flue gas, significantly improve the collection efficiency, ensure the full recovery of flue gas waste heat, ensure the best heat exchange effect, and can also effectively separate gas and liquid, mix the harmful substances in the flue gas with the liquid, ensure that the discharged gas is clean, and overall improve the environmental protection and economic benefits of the system.

[0012] To achieve the above object of the invention, the technical solution of the present invention is: an electric arc furnace flue gas waste heat recovery system, including a treatment furnace, a smoke collection hood is provided on the side of the treatment furnace above the electric arc furnace, and a flue gas collection unit is provided on the smoke collection hood. A pre-heat exchange unit for pre-treating heat is fixedly provided on the upper part of the treatment furnace. A post-heat exchange unit for post-treating the flue gas is provided on the lower part of the treatment furnace.

[0013] In the above electric arc furnace flue gas waste heat recovery system, the flue gas collection unit includes a smoke delivery pipe fixedly provided at the top of the treatment furnace, and the other end of the smoke delivery pipe is fixedly provided with a support block. A rotating cylinder is coaxially and fixedly provided in the middle of the support block, and the top end of the smoke collection hood is rotatably provided on the rotating cylinder.

[0014] The middle position of the smoke delivery pipe has an inclined structure with one side high and the other side low, and the smoke delivery pipe above the smoke collection hood is higher than the smoke delivery pipe above the treatment furnace.

[0015] In the above electric arc furnace flue gas waste heat recovery system, a gear ring is horizontally and fixedly provided at the top end of the rotating cylinder, a support is fixedly provided at the top end of the smoke collection hood, a motor is vertically and fixedly provided on the support, and a gear meshing with the gear ring is fixedly provided at the output end of the motor.

[0016] The smoke collecting hood is in the shape of a horn with an opening facing downward, and a plurality of first exhaust fans with motors are arranged on the circumference of the middle part thereof. A second exhaust fan is fixedly arranged on the smoke delivery pipe above the support block. A sealing cover that can cover the second exhaust fan and the motor is fixedly arranged on the smoke delivery pipe, and the bottom end of the sealing cover abuts against the top end of the smoke collecting hood.

[0017] In the above-mentioned electric arc furnace flue gas waste heat recovery system, a top cover is fixedly arranged at the top end of the treatment furnace, and a steam outlet is opened at the top end of the top cover. A partition plate is horizontally arranged at the middle position inside the treatment furnace, and the partition plate divides the treatment furnace into a pretreatment area and a post-treatment area.

[0018] In the above-mentioned electric arc furnace flue gas waste heat recovery system, the pre-heat exchange unit includes a spiral pipe fixedly arranged inside the pretreatment area. The top inlet of the spiral pipe penetrates through the top end of the top cover and is fixedly arranged with the end of the smoke delivery pipe. The bottom outlet of the spiral pipe penetrates through the partition plate and extends into the inside of the post-treatment area.

[0019] A first temperature sensor is fixedly arranged inside the pretreatment area, and a drain pipe is opened at the bottom of the pretreatment area.

[0020] In the above-mentioned electric arc furnace flue gas waste heat recovery system, the pre-heat exchange unit further includes a liquid storage tank fixedly arranged on the side of the treatment furnace. Two partition plates are horizontally and fixedly arranged inside the liquid storage tank, and the partition plates divide the liquid storage tank into a water inlet chamber, a cold water chamber, and a temperature adjustment chamber from bottom to top in sequence.

[0021] A water inlet pipe that penetrates through the side wall of the liquid storage tank is fixedly and communicatively arranged on the side of the water inlet chamber. A first liquid extraction pump that penetrates through the partition plate and extends into the inside of the water inlet chamber is fixedly arranged inside the cold water chamber. A second liquid extraction pump that penetrates through the partition plate and extends into the inside of the cold water chamber is fixedly arranged inside the temperature adjustment chamber. Exchange pipes that penetrate through the side wall of the liquid storage tank and are connected to an external refrigerator are fixedly and communicatively arranged on the sides of the cold water chamber and the temperature adjustment chamber.

[0022] A second temperature sensor and a third temperature sensor are respectively fixedly arranged inside the cold water chamber and the temperature adjustment chamber.

[0023] In the above-mentioned electric arc furnace flue gas waste heat recovery system, a water delivery pipe is communicatively arranged at the top end of the temperature adjustment chamber. The end of the water delivery pipe penetrates through the side wall of the treatment furnace, and its end is vertically arranged at the middle position of the pretreatment area. A plurality of first spray heads are arranged on the circumference of the vertical part of the water delivery pipe. A third liquid extraction pump is fixedly arranged at the end of the water delivery pipe inside the temperature adjustment chamber.

[0024] A distribution box is also fixedly arranged on the side wall of the treatment furnace. A communicating pipe is communicatively arranged on the side of the distribution box, and the end of the communicating pipe is communicatively connected to the water delivery pipe. A fourth liquid extraction pump is fixedly arranged on the communicating pipe on the side of the distribution box.

[0025] Inside the distribution box, a hydraulic electronic control valve is fixedly arranged, and a plurality of first liquid delivery pipes extending into the spiral pipe are communicated with the hydraulic electronic control valve. The hydraulic electronic control valve is communicated with a second liquid delivery pipe that can be inserted into the smoke delivery pipe on one side of the smoke collection hood, and the other end of the second liquid delivery pipe is fixedly provided with a second spray head.

[0026] In the above-mentioned electric arc furnace flue gas waste heat recovery system, the post-heat exchange unit includes a bearing frame horizontally and fixedly arranged at the top of the post-treatment area, and a spiral wire tube is fixedly arranged on the bearing frame. The top end of the spiral wire tube is fixedly provided with a third spray head with an upward opening, and the bottom of the hydraulic electronic control valve is communicated with a third liquid delivery pipe connected to the spiral wire tube.

[0027] In the above-mentioned electric arc furnace flue gas waste heat recovery system, the post-heat exchange unit includes a V-shaped plate horizontally and fixedly arranged at the middle position inside the post-treatment area. The V-shaped plate is horizontally arranged in the post-treatment area, and a mesh plate is fixedly arranged between the corner of the V-shaped plate and the treatment furnace.

[0028] At least one convex block is fixedly arranged at the bottom of the V-shaped plate. The convex block is an inclined surface with the bottom facing downwards. A plurality of water collecting columns are fixedly arranged at the bottom of the V-shaped plate and the bottom of the convex block. The steam is collected through the convex block and the water collecting columns to increase the liquid condensation effect. A first foam-breaking net is horizontally and fixedly arranged at the bottom of the V-shaped plate.

[0029] In the above-mentioned electric arc furnace flue gas waste heat recovery system, a fixed frame is fixedly arranged on the inner wall of the treatment furnace between the middle opening of the V-shaped plate and the treatment furnace. A second foam-breaking net is fixedly arranged on the side wall of the fixed frame. A third exhaust fan is fixedly arranged inside the fixed frame, and a smoke extraction pipe penetrating the side wall of the treatment furnace is fixedly arranged on the fixed frame at the rear of the third exhaust fan. A water outlet pipe is communicated with the inner bottom end of the post-treatment area.

[0030] Compared with the prior art, the electric arc furnace flue gas waste heat recovery system of the present invention has at least the following beneficial effects:

[0031] The electric arc furnace flue gas waste heat recovery system of the present invention realizes the efficient recovery of heat in different temperature ranges in the flue gas through the collaborative work of the pre-heat exchange unit and the post-heat exchange unit, can adjust the temperature of the liquid according to the real-time temperature, further improves the heat recovery efficiency. At the same time, the smoke collection hood adopts a trumpet-shaped structure with the opening facing downwards, and the rotation is realized by the motor driving the gear, and the diffused flue gas can be drawn into the smoke collection hood through the exhaust fan, effectively capturing and concentrating the high-temperature flue gas, reducing the loss of flue gas, and improving the collection efficiency.

[0032] The electric arc furnace flue gas waste heat recovery system of the present invention can achieve pre-heat exchange treatment of flue gas through direct contact between liquid and spiral tube, and can adjust the temperature of the liquid according to actual conditions to ensure sufficient recovery of flue gas waste heat.

[0033] The electric arc furnace flue gas waste heat recovery system of the present invention can supply liquid to the inside of the spiral tube, prolong the mixing time of the liquid and harmful substances in the flue gas, and realize the preliminary mixing of harmful substances in the flue gas and water in the spiral tube. At the same time, the inside of the spiral tube can be cleaned to avoid corrosion of the spiral tube and prolong its service life.

[0034] The electric arc furnace flue gas waste heat recovery system of the present invention can gather liquid and gas through mesh plates and mix them when they move downward, thereby mixing harmful substances in the flue gas through the liquid, which is convenient for subsequent separation and recovery, and separates the liquid and flue gas through V-shaped plates, the first foam breaking net and the second foam breaking net, so that the clean gas is separated from the liquid mixed with harmful substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 It is a schematic diagram of the structure of the smoke collection unit of the present invention;

[0037] Figure 3 is a schematic diagram of the position of the fourth liquid pump of the present invention;

[0038] Figure 4 It is a schematic diagram of the position of the cold water chamber of the present invention;

[0039] Figure 5 It is the spiral tube position diagram of the present invention;

[0040] Figure 6 It is a schematic diagram of the location of the post-processing area of the present invention;

[0041] Figure 7 It is a schematic diagram of the position of the water collection column of the present invention;

[0042] Figure 8 It is a schematic diagram of the position of the third exhaust fan of the present invention.

[0043] In the figure: 1. treatment furnace; 2. fume hood;

[0044] 3. Smoke collection unit; 301. Smoke delivery pipe; 302. Support block; 303. Rotating drum; 304. Gear ring; 305. Bracket; 306. Motor; 307. Gear; 308. First exhaust fan; 309. Second exhaust fan; 310. Sealing cover;

[0045] 4. Pre-heat exchange unit; 401. Spiral tube; 402. First temperature sensor; 403. Drain pipe; 404. Liquid storage tank; 405. Partition board; 406. Cold water chamber; 407. Cold water chamber; 408. Temperature adjustment chamber; 409. Water inlet pipe; 410. First liquid extraction pump; 411. Second liquid extraction pump; 412. Exchange pipe; 413. Second temperature sensor; 414. Third temperature sensor; 415. Water supply pipe; 416. First spray head; 417. Third liquid extraction pump; 418. Distribution box; 419. Connecting pipe; 420. Fourth liquid extraction pump; 421. Hydraulic electric control valve; 422. First liquid supply pipe; 423. Second liquid supply pipe; 424. Second spray head;

[0046] 5. Post-heat exchange unit; 501. Bearing frame; 502. Spiral tube; 503. Third spray head; 504. Third liquid supply pipe; 505. V-shaped plate; 506. Mesh plate; 507. Convex block; 508. Water collecting column; 509. First foam-breaking net; 510. Fixed frame; 511. Second foam-breaking net; 512. Third exhaust fan; 513. Smoke extraction pipe; 514. Water outlet pipe;

[0047] 6. Top cover; 7. Steam outlet; 8. Partition board; 9. Pretreatment area; 10. Post-treatment area. Detailed implementation mode

[0048] The arc furnace flue gas waste heat recovery system of the present invention will be described in more detail below with reference to the accompanying drawings and through specific implementation modes.

[0049] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0050] See Figures 1 - 8, A waste heat recovery system for the flue gas of an electric arc furnace in this embodiment can efficiently recover the heat in different temperature ranges of the flue gas, can also adjust the liquid temperature according to the real-time temperature to further improve the heat recovery efficiency, can effectively capture and concentrate the high-temperature flue gas, reduce the loss of flue gas, significantly improve the collection efficiency, ensure the full recovery of the waste heat of the flue gas, ensure the best heat exchange effect, and can also effectively separate gas and liquid, mix the harmful substances in the flue gas with the liquid, ensure that the discharged gas is clean, and overall improve the environmental protection and economic benefits of the system. In this embodiment, it mainly includes a treatment furnace 1, and the treatment furnace 1 is made of heat-insulating materials. A smoke collection hood 2 is arranged on the side of the treatment furnace 1 above the electric arc furnace, and a flue gas collection unit 3 is arranged on the smoke collection hood 2. The flue gas collection unit 3 includes a smoke delivery pipe 301 fixedly arranged at the top of the treatment furnace 1. The middle position of the smoke delivery pipe 301 has an inclined structure with one side high and one side low. The smoke delivery pipe 301 above the smoke collection hood 2 is higher than the smoke delivery pipe 301 above the treatment furnace 1. The other end of the smoke delivery pipe 301 is fixedly provided with a support block 302. A rotating cylinder 303 is coaxially and fixedly arranged in the middle of the support block 302, and the top end of the smoke collection hood 2 is rotatably arranged on the rotating cylinder 303.

[0051] A gear ring 304 is horizontally and fixedly arranged at the top end of the rotating cylinder 303. A support 305 is fixedly arranged at the top end of the smoke collection hood 2. A motor 306 is vertically and fixedly arranged on the support 305. An output end of the motor 306 is fixedly provided with a gear 307 meshing with the gear ring 304. The smoke collection hood 2 has a horn-shaped structure with an open bottom, and a plurality of first exhaust fans 308 with motors 306 are arranged on the circumference of the middle part thereof, and the range of smoke collection is expanded through the smoke collection hood 2 and the first exhaust fans 308. A second exhaust fan 309 is fixedly arranged on the smoke delivery pipe 301 above the support block 302. A sealing cover 310 that can cover the second exhaust fan 309 and the motor 306 is fixedly arranged on the smoke delivery pipe 301, and the bottom end of the sealing cover 310 abuts against the top end of the smoke collection hood 2. The inside is protected through the sealing cover 310.

[0052] When collecting the flue gas, control the second exhaust fan 309 to work, so as to draw the flue gas to the smoke delivery pipe 301 through the horn-shaped smoke collection hood 2. During this process, control the first exhaust fans 308 to work, so as to draw the flue gas that is not covered by the smoke collection hood 2 in the air into the smoke collection hood 2. At the same time, control the motor 306 to work, drive the gear 307 to rotate around the gear ring 304, so as to drive the smoke collection hood 2 to rotate around the rotating cylinder 303 through the support 305, and then draw all the flue gas at all positions in the air into the smoke delivery pipe 301 through the first exhaust fans 308. During this process, the motor 306 is protected through the sealing cover 310.

[0053] In order to realize the pretreatment of the waste heat of the flue gas, see Figures 3 - 5, in this embodiment, a top cover 6 is fixedly arranged at the top end of the processing furnace 1, and a steam outlet 7 is arranged at the top end of the top cover 6. The steam outlet 7 is externally connected to a collecting device. A partition plate 8 is horizontally arranged at the middle position inside the processing furnace 1, and the partition plate 8 divides the processing furnace 1 into a preprocessing area 9 and a post-processing area 10. A pre-heat exchange unit 4 for pre-heating heat is fixedly arranged at the upper part of the processing furnace 1. The pre-heat exchange unit 4 includes a spiral tube 401 fixedly arranged inside the preprocessing area 9. The top inlet of the spiral tube 401 penetrates through the top end of the top cover 6 and is fixedly arranged with the end of a smoke delivery pipe 301. The time of the flue gas in the preprocessing area 9 is extended through the spiral tube 401. The bottom outlet of the spiral tube 401 penetrates through the partition plate 8 and extends into the inside of the post-processing area 10. The flue gas is sent into the post-processing area 10 through the spiral tube 401. A first temperature sensor 402 is fixedly arranged inside the preprocessing area 9, which can monitor and feedback the temperature inside the preprocessing area 9 in real time. A drain pipe 403 is arranged at the bottom of the preprocessing area 9.

[0054] The pre-heat exchange unit 4 further includes a liquid storage tank 404 fixedly arranged on the side of the processing furnace 1. Two partition plates 405 are horizontally and fixedly arranged inside the liquid storage tank 404. The partition plates 405 divide the liquid storage tank 404 into a water inlet chamber 406, a cold water chamber 407, and a temperature adjustment chamber 408 from bottom to top in sequence. A water inlet pipe 409 penetrating through the side wall of the liquid storage tank 404 is fixedly connected and arranged on the side of the water inlet chamber 406. Liquid is sent into the inside of the water inlet chamber 406 through the water inlet pipe 409 for subsequent use. A first liquid pumping pump 410 penetrating through the partition plate 405 and extending into the inside of the water inlet chamber 406 is fixedly arranged inside the cold water chamber 407. The liquid in the water inlet chamber 406 is pumped into the cold water chamber 407 through the operation of the first liquid pumping pump 410. A second liquid pumping pump 411 penetrating through the partition plate 405 and extending into the inside of the cold water chamber 407 is fixedly arranged inside the temperature adjustment chamber 408. The liquid in the cold water chamber 407 is pumped into the temperature adjustment chamber 408 through the second liquid pumping pump 411. Exchange pipes 412 penetrating through the side wall of the liquid storage tank 404 and connected to an external cooler are fixedly connected and arranged on the sides of the cold water chamber 407 and the temperature adjustment chamber 408. The cooler is a mature existing technology and will not be described in detail here. It is not shown in the illustration of the present invention. Second temperature sensors 413 and third temperature sensors 414 are respectively fixedly arranged inside the cold water chamber 407 and the temperature adjustment chamber 408. The temperatures of the liquid in the cold water chamber 407 and the temperature adjustment chamber 408 are monitored in real time through the second temperature sensors 413 and the third temperature sensors 414. Thus, the liquid in the cold water chamber 407 is pumped to the external cooler for temperature reduction through the exchange pipe 412. At the same time, the temperature of the cold water in the temperature adjustment chamber 408 is controlled through the exchange pipe 412 according to the signals fed back by the first temperature sensor 402 and the third temperature sensor 414. Thus, subsequent waste heat utilization is facilitated, and at the same time, waste of resources is avoided through the adjustment of the cold water temperature.

[0055] A water supply pipe 415 is connected and arranged at the top end of the temperature control chamber 408. The end of the water supply pipe 415 penetrates through the side wall of the treatment furnace 1, and its end is vertically arranged at the middle position of the pretreatment area 9. A plurality of first spray heads 416 are circumferentially arranged on the vertical part of the water supply pipe 415. A third liquid pumping pump 417 is fixedly arranged at the end of the water supply pipe 415 inside the temperature control chamber 408. Control the third liquid pumping pump 417 to work, pump the cold water in the temperature control chamber 408 to the water supply pipe 415, and spray it from the first spray heads 416 onto the spiral pipe 401. Thus, heat exchange is carried out with the spiral pipe 401 to preprocess the heat of the flue gas. At this time, the water vapor generated when the misty water contacts the spiral pipe 401 is discharged through the steam outlet 7, and the condensed water flow is discharged from the drain pipe 403, so that the heat flows to the outside. A distribution box 418 is also fixedly arranged on the side wall of the treatment furnace 1. A connecting pipe 419 is connected and arranged on the side part of the distribution box 418. The end of the connecting pipe 419 is connected and communicated with the water supply pipe 415. A fourth liquid pumping pump 420 is fixedly arranged on the connecting pipe 419 on the side part of the distribution box 418. Control the fourth liquid pumping pump 420 to work, so as to intercept a part of the cold water in the water supply pipe 415 into the distribution box 418 through the connecting pipe 419.

[0056] A hydraulic and electric control valve 421 is fixedly arranged inside the distribution box 418. The hydraulic and electric control valve 421 is a mature existing technology and will not be described in detail here. A plurality of first liquid supply pipes 422 extending into the spiral pipe 401 are connected and arranged on the hydraulic and electric control valve 421. A second liquid supply pipe 423 that can be inserted into the smoke supply pipe 301 on one side of the smoke collecting hood 2 is connected and arranged on the hydraulic and electric control valve 421. The other end of the second liquid supply pipe 423 is fixedly provided with a second spray head 424. Control the hydraulic and electric control valve 421 to work, so as to send the cold water into the spiral pipe 401 from the first liquid supply pipe 422, and at the same time send the cold water into the inside of the smoke supply pipe 301 on one side of the smoke collecting hood 2 through the second liquid supply pipe 423, so as to send the liquid into the spiral pipe 401 through the smoke supply pipe 301 with one side high and one side low. Spray water through the first liquid supply pipe 422 and the second liquid supply pipe 423 to mix the liquid with the flue gas, extend the mixing time, and at the same time can clean the inside of the smoke supply pipe 301 and the spiral pipe 401 to avoid being corroded by the substances in the flue gas.

[0057] In order to realize the post-treatment of the waste heat of the flue gas, in this embodiment, refer to Figures 6 - 8, a post-heat exchange unit 5 for post-treating flue gas is provided at the lower part of the treatment furnace 1. The post-heat exchange unit 5 includes a carrier 501 horizontally and fixedly arranged at the top of the post-treatment area 10. A spiral tube 502 is fixedly arranged on the carrier 501. The top end of the spiral tube 502 is fixedly provided with a third spray head 503 with an upward opening. The bottom of the hydraulic and electric control valve 421 is communicated with a third liquid delivery pipe 504 connected to the spiral tube 502. By controlling the operation of the hydraulic and electric control valve 421, cold water is sent into the interior of the spiral tube 502 from the third liquid delivery pipe 504, and then the cold water is sprayed onto the bottom end of the partition plate 8 through the third spray head 503, so that the water mist fills the upper part of the post-treatment area 10.

[0058] The post-heat exchange unit 5 includes a V-shaped plate 505 horizontally and fixedly arranged at the middle position inside the post-treatment area 10. The V-shaped plate 505 is horizontally arranged in the post-treatment area 10. A mesh plate 506 is fixedly arranged between the corners of the V-shaped plate 505 and the treatment furnace 1. At least one convex block 507 is fixedly arranged at the bottom of the V-shaped plate 505. The convex block 507 is an inclined surface with the bottom downward. A plurality of water collecting columns 508 are fixedly arranged at the bottom of the V-shaped plate 505 and the bottom of the convex block 507. The steam is collected by the convex block 507 and the water collecting columns 508 to enhance the liquid condensation effect. A first foam-breaking net 509 is horizontally and fixedly arranged at the bottom of the V-shaped plate 505. The mixture of flue gas and cold water discharged from the spiral tube 401 is mixed with the water mist, so that the harmful substances in the flue gas are mixed with the liquid and separated out from the flue gas. At this time, the mixture moves downward through the V-shaped plate 505 from the mesh plate 506, and is remixed through the blockage of the mesh plate 506, and the first gas-liquid separation is achieved through the first foam-breaking net 509.

[0059] A fixed frame 510 is fixedly arranged on the inner wall of the treatment furnace 1 between the middle opening of the V-shaped plate 505 and the treatment furnace 1. A second foam-breaking net 511 is fixedly arranged on the side wall of the fixed frame 510. The second gas-liquid separation is achieved through the second foam-breaking net 511. A third exhaust fan 512 is fixedly arranged inside the fixed frame 510. The flue gas is extracted through the third exhaust fan 512 and the second exhaust fan 309 to provide power for the movement of the flue gas. A smoking pipe 513 penetrating the side wall of the treatment furnace 1 is fixedly arranged on the fixed frame 510 behind the third exhaust fan 512, and the separated pure flue gas is discharged outwards from the smoking pipe 513. A water outlet pipe 514 is communicated with the inner bottom end of the post-treatment area 10. The separated liquid containing harmful substances is discharged to the outside from the water outlet pipe 514 for further treatment.

[0060] Usage method of the waste heat recovery system for the electric arc furnace flue gas of the present invention: First, when collecting the flue gas, control the second exhaust fan 309 and the third exhaust fan 512 to work to provide power for the movement of the flue gas. The flue gas is drawn towards the smoke delivery pipe 301 through the horn-shaped smoke collecting hood 2. During this process, control the first exhaust fan 308 to work, so as to draw the flue gas that is not covered by the smoke collecting hood 2 in the air into the smoke collecting hood 2. At the same time, control the motor 306 to work, drive the gear 307 to rotate around the gear ring 304, and then drive the smoke collecting hood 2 to rotate around the rotating cylinder 303 through the support 305, and further draw all the flue gas in the air into the smoke delivery pipe 301 through the first exhaust fan 308. During this process, protect the motor 306 through the sealing cover 310.

[0061] Send the liquid into the interior of the water inlet cavity 406 through the water inlet pipe 409, pump the liquid in the water inlet cavity 406 into the cold water cavity 407 through the first liquid pump 410, and pump the liquid in the cold water cavity 407 into the temperature adjustment cavity 408 through the second liquid pump 411. Real-time monitor the temperatures of the liquid in the cold water cavity 407 and the temperature adjustment cavity 408 through the second temperature sensor 413 and the third temperature sensor 414, so as to draw the liquid in the cold water cavity 407 to an external refrigerator through the exchange pipe 412 to reduce the temperature, and at the same time control the temperature of the cold water in the temperature adjustment cavity 408 according to the signals fed back by the first temperature sensor 402 and the third temperature sensor 414 through the exchange pipe 412, so as to facilitate subsequent waste heat utilization, and at the same time avoid wasting resources through the adjustment of the cold water temperature.

[0062] Control the third liquid pump 417 to work, pump the cold water in the temperature adjustment cavity 408 into the water delivery pipe 415, and spray it from the first spray head 416 onto the spiral pipe 401. Thus, heat exchange is carried out with the spiral pipe 401 to preprocess the heat of the flue gas. At this time, the water vapor generated when the misty water contacts the spiral pipe 401 is discharged through the steam outlet 7, and the condensed water flows out from the drain pipe 403, so that the heat flows to the outside. Control the fourth liquid pump 420 to work, so as to intercept a part of the cold water in the water delivery pipe 415 into the distribution box 418 through the connecting pipe 419. Control the hydraulic and electric control valve 421 to work, so as to send the cold water into the spiral pipe 401 through the first liquid delivery pipe 422, and at the same time send the cold water into the interior of the smoke delivery pipe 301 on one side of the smoke collecting hood 2 through the second liquid delivery pipe 423, so as to send the liquid into the spiral pipe 401 through the smoke delivery pipe 301 with one side high and one side low. Spray water through the first liquid delivery pipe 422 and the second liquid delivery pipe 423 to mix the liquid with the flue gas, lengthen the mixing time, and at the same time clean the interiors of the smoke delivery pipe 301 and the spiral pipe 401 to avoid being corroded by the substances in the flue gas.

[0063] The control hydraulic and electric control valve 421 sends cold water from the third liquid delivery pipe 504 into the interior of the spiral tube 502, so as to spray the cold water towards the bottom end of the partition plate 8 through the third spray head 503, making the upper part of the post-treatment area 10 filled with water mist. The mixture of flue gas and cold water discharged from the spiral tube 401 into the post-treatment area 10 is mixed with the water mist, so that the harmful substances in the flue gas are mixed with the liquid and separated out from the flue gas. At this time, the mixture moves downward from the mesh plate 506 through the V-shaped plate 505, and is mixed again through the blocking of the mesh plate 506, and the first gas-liquid separation is achieved through the first demisting net 509. During this process, the steam is collected by the bump 507 and the water collecting column 508 to enhance the liquid condensation effect. The second gas-liquid separation is achieved through the second demisting net 511, and the purified flue gas after separation is discharged outwards from the smoking pipe 513, and the liquid with harmful substances after separation is discharged to the outside from the water outlet pipe 514 for the next step of treatment.

[0064] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. Words such as "a" or "an" used in the specification and claims of this application do not necessarily indicate a limitation in quantity. Words such as "comprising" or "including" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0065] The exemplary embodiments of the present invention have been described in detail above with reference to the preferred embodiments. However, those skilled in the art can understand that, without departing from the concept of the present invention, various modifications and variations can be made to the above specific embodiments, and various combinations can be made to the technical features and structures proposed by the present invention, without exceeding the protection scope of the present invention.

Claims

1. An electric arc furnace flue gas waste heat recovery system, characterized in that: It includes a processing furnace (1), a smoke collecting hood (2) is arranged on the side of the processing furnace (1) and is located above the electric arc furnace, a flue gas collecting unit (3) is arranged on the smoke collecting hood (2), a pre-heat exchange unit (4) capable of pre-treating heat is fixedly arranged on the upper part of the processing furnace (1), and a post-heat exchange unit (5) capable of post-treating the flue gas is arranged on the lower part of the processing furnace (1); The flue gas collecting unit (3) includes a smoke delivery pipe (301) fixedly arranged at the top end of the processing furnace (1). The middle position of the smoke delivery pipe (301) has an inclined structure with one side high and one side low. The smoke delivery pipe (301) above the smoke collecting hood (2) is higher than the smoke delivery pipe (301) above the processing furnace (1); The pre-heat exchange unit (4) includes a spiral pipe (401) fixedly arranged inside a pre-treatment area (9). The bottom outlet of the spiral pipe (401) penetrates through a partition plate (8) and extends into the interior of a post-treatment area (10). A distribution box (418) is also fixedly arranged on the side wall of the processing furnace (1). A hydraulic and electric control valve (421) is fixedly arranged inside the distribution box (418). A plurality of first liquid delivery pipes (422) extending into the spiral pipe (401) are communicated with the hydraulic and electric control valve (421). A second liquid delivery pipe (423) that can be inserted into the smoke delivery pipe (301) on one side of the smoke collecting hood (2) is communicated with the hydraulic and electric control valve (421); The post-heat exchange unit (5) includes a bearing frame (501) horizontally and fixedly arranged at the top of the post-treatment area (10). A spiral tube (502) is fixedly arranged on the bearing frame (501). A third liquid delivery pipe (504) communicated with the spiral tube (502) is connected to the bottom of the hydraulic and electric control valve (421). The post-heat exchange unit (5) includes a V-shaped plate (505) horizontally and fixedly arranged at the middle position inside the post-treatment area (10). The V-shaped plate (505) is horizontally arranged inside the post-treatment area (10). A mesh plate (506) is fixedly arranged between the corner of the V-shaped plate (505) and the processing furnace (1). A first foam-breaking net (509) is horizontally and fixedly arranged at the bottom of the V-shaped plate (505). A fixed frame (510) is fixedly arranged on the inner wall of the processing furnace (1) between the middle opening of the V-shaped plate (505) and the processing furnace (1). A second foam-breaking net (511) is fixedly arranged on the side wall of the fixed frame (510); At least one convex block (507) is fixedly arranged at the bottom of the V-shaped plate (505). The convex block (507) has an inclined surface with the bottom facing downwards. A plurality of water collecting columns (508) are fixedly arranged at the bottom of the V-shaped plate (505) and the bottom of the convex block (507).

2. The waste heat recovery system for the flue gas of an electric arc furnace according to claim 1, characterized in that: The other end of the smoke delivery pipe (301) is fixedly provided with a support block (302). A rotating cylinder (303) is coaxially and fixedly arranged in the middle of the support block (302). The top end of the smoke collecting hood (2) is rotatably arranged on the rotating cylinder (303).

3. The waste heat recovery system for the flue gas of an electric arc furnace according to claim 2, wherein: A gear ring (304) is horizontally and fixedly arranged at the top end of the rotary drum (303). A bracket (305) is fixedly arranged at the top end of the smoke collecting hood (2). A motor (306) is vertically and fixedly arranged on the bracket (305). An output end of the motor (306) is fixedly provided with a gear (307) meshing with the gear ring (304). The smoke collecting hood (2) is in a horn-shaped structure with an opening facing downward, and a plurality of first exhaust fans (308) with motors (306) are arranged on the circumference of the middle part thereof. A second exhaust fan (309) is fixedly arranged on the smoke delivery pipe (301) above the support block (302). A sealing cover (310) capable of covering the second exhaust fan (309) and the motor (306) is fixedly arranged on the smoke delivery pipe (301). A bottom end of the sealing cover (310) abuts against a top end of the smoke collecting hood (2).

4. The waste heat recovery system for the electric arc furnace flue gas according to claim 3, characterized in that: A top cover (6) is fixedly arranged at the top end of the treatment furnace (1). A steam outlet (7) is opened at the top end of the top cover (6). A partition plate (8) is horizontally arranged at an intermediate position inside the treatment furnace (1). The partition plate (8) divides the treatment furnace (1) into a pretreatment area (9) and a post-treatment area (10).

5. The waste heat recovery system for the electric arc furnace flue gas according to claim 4, characterized in that: A top end inlet of the spiral pipe (401) penetrates through the top end of the top cover (6) and is fixedly arranged with an end of the smoke delivery pipe (301). A first temperature sensor (402) is fixedly arranged inside the pretreatment area (9). A drain pipe (403) is opened at the bottom of the pretreatment area (9).

6. The waste heat recovery system for the off-gas of an electric arc furnace according to claim 5, wherein: The pre-heat exchange unit (4) further includes a liquid storage tank (404) fixedly arranged on a side portion of the treatment furnace (1). Two partition plates (405) are horizontally and fixedly arranged inside the liquid storage tank (404). The partition plates (405) divide the liquid storage tank (404) into a water inlet chamber (406), a cold water chamber (407), and a temperature adjustment chamber (408) from bottom to top in sequence. A water inlet pipe (409) penetrating through a side wall of the liquid storage tank (404) is fixedly and communicatively arranged on a side portion of the water inlet chamber (406). A first liquid extraction pump (410) penetrating through the partition plate (405) and extending into the water inlet chamber (406) is fixedly arranged inside the cold water chamber (407). A second liquid extraction pump (411) penetrating through the partition plate (405) and extending into the cold water chamber (407) is fixedly arranged inside the temperature adjustment chamber (408). Exchange pipes (412) penetrating through the side wall of the liquid storage tank (404) and connected to an external refrigerator are fixedly and communicatively arranged on side portions of the cold water chamber (407) and the temperature adjustment chamber (408). A second temperature sensor (413) and a third temperature sensor (414) are respectively fixedly arranged inside the cold water chamber (407) and the temperature adjustment chamber (408).

7. An electric arc furnace flue gas waste heat recovery system according to claim 6, characterized in that: A water supply pipe (415) is connected to the top end of the temperature control chamber (408). The end of the water supply pipe (415) penetrates through the side wall of the treatment furnace (1) and its end is vertically arranged at the middle position of the pretreatment area (9). A plurality of first spray nozzles (416) are circumferentially arranged on the vertical part of the water supply pipe (415). A third liquid extraction pump (417) is fixedly arranged at the end of the water supply pipe (415) inside the temperature control chamber (408); A connecting pipe (419) is connected to the side part of the distribution box (418). The end of the connecting pipe (419) is connected to the water supply pipe (415). A fourth liquid extraction pump (420) is fixedly arranged on the connecting pipe (419) at the side part of the distribution box (418); The other end of the second liquid supply pipe (423) is fixedly provided with a second spray nozzle (424).

8. A waste heat recovery system for the flue gas of an electric arc furnace according to claim 1, characterized in that: A third spray nozzle (503) with an upward opening is fixedly arranged at the top end of the spiral wire tube (502).

9. The waste heat recovery system for the off-gas of an electric arc furnace according to claim 1, characterized in that: A third extraction fan (512) is fixedly arranged inside the fixed frame (510). A smoke extraction pipe (513) penetrating through the side wall of the treatment furnace (1) is fixedly arranged on the fixed frame (510) at the rear of the third extraction fan (512). A water outlet pipe (514) is connected to the inner bottom end of the post-treatment area (10).

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