Flue gas waste heat recovery system of electric arc furnace

Abstract

The invention relates to the field of flue gas recovery, in particular to an electric arc furnace flue gas waste heat recovery system which comprises a treatment furnace, a flue gas collecting hood located above an electric arc furnace is arranged on the side portion of the treatment furnace, a flue gas collecting unit is arranged on the flue gas collecting hood, and a heat pre-exchange unit capable of pre-treating heat is fixedly arranged on the upper portion of the treatment furnace. The lower part of the treatment furnace is provided with a rear heat exchange unit capable of performing post-treatment on the flue gas; heat in different temperature intervals in flue gas can be efficiently recovered, the liquid temperature can be adjusted according to the real-time temperature, the heat recovery efficiency is further improved, high-temperature flue gas can be effectively captured and concentrated, flue gas loss is reduced, the collection efficiency is remarkably improved, sufficient recovery of flue gas waste heat is guaranteed, the optimal heat exchange effect is guaranteed, and the heat recovery efficiency is improved. And gas and liquid can be effectively separated, so that harmful substances in the flue gas are mixed with the liquid, the discharged gas is ensured to be clean, and the environmental protection property and the economic benefit of the system are integrally improved.

Description

Technical Field

[0001] The invention relates to the field of flue gas recovery, in particular to an arc furnace flue gas waste heat recovery system. Background Art

[0002] Electric arc furnaces (EAFs) produce a large amount of high-temperature flue gas during steel production, which contains a lot of heat. However, traditional EAFs usually discharge this part of flue gas directly into the atmosphere, which not only wastes precious thermal energy resources, but also increases the environmental burden.

[0003] The Chinese patent application number 201410215970.3 discloses an industrial electric arc furnace waste heat utilization and flue gas recovery device, in which a smoke dust collection hood is arranged above the electric arc furnace, the smoke dust collection hood is connected to a smoke exhaust pipeline provided with a dust removal mechanism, the dust removal mechanism is connected to an exhaust pipe, and the exhaust pipe discharges the smoke into a waste heat furnace connected to the exhaust pipe to recover waste heat; the electric arc furnace is also connected to a combustion settling chamber, the combustion settling chamber is connected to a heat pipe evaporator, and the heat pipe evaporator is connected to a high-pressure steam bag to provide high-pressure steam for use by other equipment; the device collects smoke for purification and waste heat recovery by arranging a smoke dust collection hood above the electric arc furnace, and also arranges a waste heat recovery device on the settling chamber connected to the electric arc furnace, adopts two methods to simultaneously recover and purify waste heat from smoke dust and smoke, maximizes heat utilization, and is suitable for production.

[0004] The Chinese patent application number 200610088072.1 discloses a waste heat recovery system for cooling exhaust gas in an electric arc furnace and a recovery method thereof, which mainly adopts a heat pipe steam generator connected to a combustion settling chamber through an insulation pipe, a heat pipe steam generator connected to a dust collector, a dust collector connected to a main fan, and a main fan connected to an exhaust pipe. The exhaust gas in the electric arc furnace is discharged, mixed with cold air through a water-cooled sliding sleeve, and enters the combustion settling chamber. The flue gas coming out of the combustion settling chamber directly enters the heat pipe steam generator through an insulation flue, and the flue gas coming out of the heat pipe steam generator directly enters or mixes with other flue gases and enters the dust collector for dust removal, and then is pressed into the exhaust pipe by the main fan and discharged into the atmosphere. The present invention can efficiently cool high-temperature flue gas, recover the heat energy in the flue gas to the maximum extent, and improve the dust removal capacity; it can reduce the system air volume and reduce the operating cost; the heat pipe steam generator operates reliably and stably, meeting the requirements of normal production.

[0005] However, there are still the following problems in practical applications, specifically: 1. Failure to fully consider the unique working conditions and flue gas characteristics of the electric arc furnace.

[0006] 2. The processing of the flue gas temperature range is not sophisticated enough, and it is difficult to adapt to the complex flue gas composition and temperature changes of the electric arc furnace. The liquid temperature cannot be adjusted according to the real-time temperature, which affects the heat exchange effect.

[0007] 3. The maintenance cost is high and requires frequent manual intervention.

[0008] 4. There is a lack of effective separation design for harmful substances in flue gas, and the exhausted gas still contains a certain amount of harmful substances, and the environmental protection performance is limited.

[0009] Therefore, how to overcome the above-mentioned technical problems and defects becomes a key issue that needs to be solved. Summary of the invention

[0010] The purpose of the present invention is to overcome the defects described in the background technology, thereby realizing an electric arc furnace flue gas waste heat recovery system, which can realize efficient recovery of heat in different temperature ranges in the flue gas, and can also adjust the liquid temperature according to the real-time temperature to further improve the heat recovery efficiency. It can also effectively capture and concentrate high-temperature flue gas, reduce flue gas loss, significantly improve the collection efficiency, ensure full recovery of flue gas waste heat, ensure the best heat exchange effect, and effectively separate gas and liquid, so that harmful substances in the flue gas are mixed with the liquid, ensuring that the discharged gas is clean, thereby improving the environmental protection and economic benefits of the system as a whole.

[0011] To achieve the above-mentioned invention object, the technical solution of the present invention is: an arc furnace flue gas waste heat recovery system, comprising a treatment furnace, a smoke collecting hood located above the arc furnace is arranged on the side of the treatment furnace, and a smoke collecting unit is arranged on the smoke collecting hood. A pre-heat exchange unit for pre-processing heat is fixedly arranged on the upper part of the treatment furnace. A post-heat exchange unit for post-processing flue gas is arranged on the lower part of the treatment furnace.

[0012] In the above arc furnace flue gas waste heat recovery system, the flue gas collection unit includes a smoke delivery pipe fixedly arranged at the top of the treatment furnace, and a support block is fixedly arranged at the other end of the smoke delivery pipe. A rotating drum is coaxially fixedly arranged in the middle of the support block, and the top of the smoke hood is rotatably arranged on the rotating drum.

[0013] The middle position of the smoke delivery pipe is an inclined structure with one side high and the other side low, and the smoke delivery pipe above the smoke collecting hood is higher than the smoke delivery pipe above the processing furnace.

[0014] In the above-mentioned arc furnace flue gas waste heat recovery system, a gear ring is horizontally fixed on the top of the rotating drum, a bracket is fixed on the top of the smoke hood, a motor is vertically fixed on the bracket, and a gear meshing with the gear ring is fixed on the output end of the motor.

[0015] The smoke collecting hood is a trumpet-shaped structure with an opening facing downwards and a plurality of first exhaust fans with motors are arranged on the central circumference thereof, and 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.

[0016] In the above arc furnace flue gas waste heat recovery system, a top cover is fixedly arranged at the top of the treatment furnace, and a steam outlet is opened at the top 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 pre-treatment area and a post-treatment area.

[0017] In the above arc furnace flue gas waste heat recovery system, the pre-heat exchange unit includes a spiral tube fixedly arranged inside the pre-treatment zone, the top inlet of the spiral tube passes through the top of the top cover and the end of the smoke delivery pipe and is fixedly arranged. The bottom outlet of the spiral tube passes through the partition plate and extends into the interior of the post-treatment zone.

[0018] A first temperature sensor is fixedly arranged inside the pretreatment area, and a drainage pipe is provided at the bottom of the pretreatment area.

[0019] In the above arc furnace flue gas waste heat recovery system, the pre-heat exchange unit also includes a liquid storage tank fixedly arranged on the side of the treatment furnace. Two isolation plates are fixedly arranged horizontally inside the liquid storage tank, and the isolation plates divide the liquid storage tank into a water inlet chamber, a cold water chamber and a temperature adjustment chamber from bottom to top.

[0020] The side of the water inlet cavity is fixedly connected with a water inlet pipe penetrating the side wall of the liquid storage tank, the interior of the cold water cavity is fixedly provided with a first liquid pump penetrating the isolation plate and extending into the water inlet cavity, and the interior of the temperature regulating cavity is fixedly provided with a second liquid pump penetrating the isolation plate and extending into the cold water cavity. The sides of the cold water cavity and the temperature regulating cavity are both fixedly connected with an exchange tube penetrating the side wall of the liquid storage tank and connected to an external refrigerator.

[0021] A second temperature sensor and a third temperature sensor are fixedly arranged inside the cold water chamber and the temperature adjustment chamber respectively.

[0022] In the above-mentioned arc furnace flue gas waste heat recovery system, a water supply pipe is connected to the top of the temperature adjustment chamber, and the end of the water supply pipe passes through the side wall of the treatment furnace and its end is vertically arranged in the middle of the pretreatment area. A plurality of first spray heads are arranged on the circumference of the vertical part of the water supply pipe. A third liquid pump is fixedly arranged at the end of the water supply pipe inside the temperature adjustment chamber.

[0023] A distribution box is also fixedly arranged on the side wall of the treatment furnace, a connecting pipe is connected to the side of the distribution box, the end of the connecting pipe is connected to the water supply pipe, and a fourth liquid pump is fixedly arranged on the connecting pipe on the side of the distribution box.

[0024] A hydraulic electric control valve is fixedly arranged inside the distribution box, and a plurality of first liquid delivery pipes extending into the spiral tube are connected to the hydraulic electric control valve. A second liquid delivery pipe which can be inserted into the smoke delivery pipe on one side of the smoke collecting hood is connected to the hydraulic electric control valve, and a second spray head is fixedly arranged at the other end of the second liquid delivery pipe.

[0025] In the above-mentioned arc furnace flue gas waste heat recovery system, the post-heat exchange unit includes a support frame fixedly arranged horizontally on the top of the post-processing area, and a vortex wire tube is fixedly arranged on the support frame. A third spray head with an upward opening is fixedly arranged on the top of the vortex wire tube, and a third liquid delivery pipe connected to the vortex wire tube is connected to the bottom of the hydraulic electric control valve.

[0026] In the above-mentioned electric arc furnace flue gas waste heat recovery system, the post-heat exchange unit includes a V-shaped plate fixedly arranged horizontally in the middle position inside the post-processing area, the V-shaped plate is horizontally placed in the post-processing area, and a mesh plate is fixedly arranged between the corner of the V-shaped plate and the processing furnace.

[0027] At least one protrusion is fixedly provided at the bottom of the V-shaped plate, and the protrusion is a downwardly inclined surface at the bottom. A plurality of water collecting columns are fixedly provided at the bottom of the V-shaped plate and the bottom of the protrusion. The steam is collected by the protrusion and the water collecting column to increase the condensation effect of the liquid. A first foam breaking net is fixedly provided horizontally at the bottom of the V-shaped plate.

[0028] In the above-mentioned arc furnace flue gas waste heat recovery system, a fixing 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, and a second foam breaking net is fixedly arranged on the side wall of the fixing frame. A third exhaust fan is fixedly arranged inside the fixing frame, and a smoke extraction pipe penetrating the side wall of the treatment furnace is fixedly arranged on the fixing frame at the rear of the third exhaust fan, and a water outlet pipe is connected to the bottom end of the interior of the post-processing area.

[0029] 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: The electric arc furnace flue gas waste heat recovery system of the present invention realizes efficient recovery of heat in different temperature ranges in the flue gas through the coordinated work of the pre-heat exchange unit and the post-heat exchange unit, and can adjust the temperature of the liquid according to the real-time temperature to further improve the heat recovery efficiency. At the same time, the smoke hood adopts a trumpet-shaped structure with the opening facing downward, and is rotated by a motor-driven gear, and can draw the diffused smoke into the smoke hood through an exhaust fan, effectively capturing and concentrating high-temperature smoke, reducing smoke loss, and improving collection efficiency.

[0030] 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.

[0031] 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.

[0032] 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

[0033] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the structure of the smoke collection unit of the present invention; Figure 3 is a schematic diagram of the position of the fourth liquid pump of the present invention; Figure 4 It is a schematic diagram of the position of the cold water chamber of the present invention; Figure 5 It is the spiral tube position diagram of the present invention; Figure 6 It is a schematic diagram of the location of the post-processing area of ​​the present invention; Figure 7 It is a schematic diagram of the position of the water collection column of the present invention; Figure 8 It is a schematic diagram of the position of the third exhaust fan of the present invention.

[0034] In the figure: 1. treatment furnace; 2. fume hood; 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; 4. Preheat exchange unit; 401. Spiral tube; 402. First temperature sensor; 403. Drain pipe; 404. Liquid storage tank; 405. Isolation plate; 406. Cold water chamber; 407. Cold water chamber; 408. Temperature adjustment chamber; 409. Water inlet pipe; 410. First liquid pump; 411. Second liquid pump; 412. Exchange pipe; 413. Second temperature sensor; 414. Third temperature sensor; 415. Water delivery pipe; 416. First spray head; 417. Third liquid pump; 418. Distribution box; 419. Connecting pipe; 420. Fourth liquid pump; 421. Hydraulic electric control valve; 422. First liquid delivery pipe; 423. Second liquid delivery pipe; 424. Second spray head; 5. rear heat exchange unit; 501. carrier frame; 502. vortex line tube; 503. third spray head; 504. third liquid delivery pipe; 505. V-shaped plate; 506. mesh plate; 507. convex block; 508. water collecting column; 509. first foam breaking net; 510. fixing frame; 511. second foam breaking net; 512. third exhaust fan; 513. smoke pipe; 514. water outlet pipe; 6. Top cover; 7. Steam outlet; 8. Partition plate; 9. Pretreatment area; 10. Post-treatment area. DETAILED DESCRIPTION

[0035] The arc furnace flue gas waste heat recovery system of the present invention is described in more detail below with reference to the accompanying drawings and through specific implementation methods.

[0036] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are 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 cannot be understood as a limitation on the present invention.

[0037] See also Figure 1-Figure 8, an arc furnace flue gas waste heat recovery system of this embodiment can realize efficient recovery of heat in different temperature ranges in the flue gas, and can also adjust the liquid temperature according to the real-time temperature to further improve the heat recovery efficiency, and can also effectively capture and concentrate high-temperature flue gas, reduce flue gas loss, significantly improve the collection efficiency, ensure the full recovery of flue gas waste heat, ensure the best heat exchange effect, and can effectively separate gas and liquid, so that harmful substances in the flue gas are mixed with liquid, ensure that the discharged gas is clean, and improve the environmental protection and economic benefits of the system as a whole. In this embodiment, it mainly includes a treatment furnace 1, and the treatment furnace 1 is made of heat-insulating materials. A smoke collecting hood 2 located above the arc furnace is provided on the side of the treatment furnace 1, and a smoke collecting unit 3 is provided on the smoke collecting hood 2. The smoke collecting unit 3 includes a smoke delivery pipe 301 fixedly arranged at the top of the treatment furnace 1, and the middle position of the smoke delivery pipe 301 is an inclined structure with one side high and one side low, and the smoke delivery pipe 301 above the smoke collection hood 2 is higher than the smoke delivery pipe 301 above the treatment furnace 1. A support block 302 is fixedly disposed at the other end of the smoke delivery pipe 301. A rotating drum 303 is coaxially fixedly disposed in the middle of the support block 302, and the top end of the smoke collecting hood 2 is rotatably disposed on the rotating drum 303.

[0038] A gear ring 304 is fixedly arranged horizontally on the top of the rotating drum 303, a bracket 305 is fixedly arranged on the top of the smoke hood 2, a motor 306 is fixedly arranged vertically on the bracket 305, and a gear 307 meshing with the gear ring 304 is fixedly arranged at the output end of the motor 306. The smoke hood 2 is a trumpet-shaped structure with an opening facing downward, and a plurality of first exhaust fans 308 with motors 306 are arranged on the central circumference thereof, and the range of smoke collection is expanded by the smoke 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 of the smoke hood 2. The interior is protected by the sealing cover 310.

[0039] When collecting smoke, the second exhaust fan 309 is controlled to work, so that the smoke is sucked into the smoke delivery pipe 301 through the trumpet-shaped smoke collection hood 2. In this process, the first exhaust fan 308 is controlled to work, so that the smoke in the air that is not covered by the smoke collection hood 2 is sucked into the smoke collection hood 2, and the motor 306 is controlled to work, and the driving gear 307 rotates around the gear ring 304, so that the smoke collection hood 2 is driven to rotate around the rotating drum 303 through the bracket 305, and then the smoke at all positions in the air is sucked into the smoke delivery pipe 301 through the first exhaust fan 308. In this process, the motor 306 is protected by the sealing cover 310.

[0040] In order to realize the pretreatment of flue gas waste heat, see Figure 3-Figure 5In this embodiment, a top cover 6 is fixedly provided at the top of the treatment furnace 1, and a steam outlet 7 is provided at the top of the top cover 6. The steam outlet 7 is connected to a collection device. A partition plate 8 is horizontally provided at the middle position inside the treatment furnace 1, and the partition plate 8 divides the treatment furnace 1 into a pretreatment area 9 and a post-treatment area 10. A preheat exchange unit 4 for pre-treatment of heat is fixedly provided at the upper part of the treatment furnace 1. The preheat exchange unit 4 includes a spiral tube 401 fixedly provided inside the pretreatment area 9, and the top inlet of the spiral tube 401 is fixedly provided through the top of the top cover 6 and the end of the smoke delivery pipe 301. The time of the flue gas in the pretreatment area 9 is extended by the spiral tube 401. The bottom outlet of the spiral tube 401 penetrates the partition plate 8 and extends into the interior of the post-treatment area 10. The flue gas is delivered into the post-treatment area 10 through the spiral tube 401. A first temperature sensor 402 is fixedly provided inside the pretreatment area 9, which can monitor and feedback the temperature in the pretreatment area 9 in real time. A drain pipe 403 is provided at the bottom of the pretreatment area 9.

[0041] The preheat exchange unit 4 also includes a liquid storage tank 404 fixedly arranged on the side of the treatment furnace 1. Two isolation plates 405 are fixedly arranged horizontally inside the liquid storage tank 404, and the isolation 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. A water inlet pipe 409 is fixedly arranged on the side of the water inlet chamber 406 and passes through the side wall of the liquid storage tank 404. Liquid is sent into the water inlet chamber 406 through the water inlet pipe 409, which is convenient for subsequent use. A first liquid pumping pump 410 is fixedly arranged inside the cold water chamber 407, which passes through the isolation plate 405 and extends into the water inlet chamber 406. The liquid in the water inlet chamber 406 is pumped into the cold water chamber 407 through the first liquid pumping pump 410. A second liquid pumping pump 411 is fixedly arranged inside the temperature adjustment chamber 408, which passes through the isolation plate 405 and extends into the cold water chamber 407. The liquid in the cold water chamber 407 is pumped to the temperature regulating chamber 408 by the second pumping pump 411. The sides of the cold water chamber 407 and the temperature regulating chamber 408 are fixedly connected with an exchange tube 412 that penetrates the side wall of the liquid storage tank 404 and is connected to an external refrigerator. The refrigerator is a mature prior art, which will not be described in detail here and is not shown in the diagram of the present invention. The inside of the cold water chamber 407 and the temperature regulating chamber 408 is respectively fixedly provided with a second temperature sensor 413 and a third temperature sensor 414. The temperature of the liquid in the cold water chamber 407 and the temperature regulating chamber 408 is monitored in real time by the second temperature sensor 413 and the third temperature sensor 414, so that the liquid in the cold water chamber 407 is pumped to the external refrigerator through the exchange tube 412 to reduce the temperature. At the same time, the temperature of the cold water in the temperature regulating chamber 408 is controlled through the exchange tube 412 according to the feedback signals of the first temperature sensor 402 and the third temperature sensor 414, so as to facilitate the subsequent waste heat utilization and avoid the waste of resources by adjusting the cold water temperature.

[0042] The top of the temperature regulating chamber 408 is connected to a water supply pipe 415, the end of which passes through the side wall of the treatment furnace 1 and is vertically arranged in the middle of the pretreatment zone 9. A plurality of first spray heads 416 are arranged on the circumference of the vertical part of the water supply pipe 415. A third liquid pump 417 is fixedly arranged at the end of the water supply pipe 415 inside the temperature regulating chamber 408. The third liquid pump 417 is controlled to work, and the cold water in the temperature regulating chamber 408 is pumped to the water supply pipe 415, and sprayed from the first spray head 416 to the spiral tube 401. Thus, heat is exchanged with the spiral tube 401, and the heat of the flue gas is pretreated. At this time, the water vapor generated when the mist water contacts the spiral tube 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 provided on the side wall of the treatment furnace 1. A connecting pipe 419 is connected to the side of the distribution box 418. The end of the connecting pipe 419 is connected to the water supply pipe 415. A fourth liquid pump 420 is fixedly provided on the connecting pipe 419 at the side of the distribution box 418. The fourth liquid pump 420 is controlled to work so that a part of the cold water in the water supply pipe 415 is intercepted into the distribution box 418 through the connecting pipe 419.

[0043] A hydraulic electric control valve 421 is fixedly arranged inside the distribution box 418. The hydraulic electric control valve 421 is a mature existing technology and will not be described in detail here. The hydraulic electric control valve 421 is connected to a plurality of first liquid delivery pipes 422 extending into the interior of the spiral tube 401. The hydraulic electric control valve 421 is connected to a second liquid delivery pipe 423 that can be inserted into the smoke delivery pipe 301 on one side of the smoke hood 2, and a second spray head 424 is fixedly arranged at the other end of the second liquid delivery pipe 423. The hydraulic electric control valve 421 is controlled to work, so that cold water is delivered from the first liquid delivery pipe 422 into the spiral tube 401, and at the same time, the cold water is delivered into the interior of the smoke delivery pipe 301 on one side of the smoke hood 2 through the second liquid delivery pipe 423, so that the liquid is delivered into the spiral tube 401 through the smoke delivery pipe 301 that is high on one side and low on the other side. Water is sprayed through the first liquid delivery pipe 422 and the second liquid delivery pipe 423 to mix the liquid with the smoke, thereby prolonging the mixing time. At the same time, the inside of the smoke delivery pipe 301 and the spiral tube 401 can be cleaned to avoid corrosion by substances in the smoke.

[0044] In order to achieve post-processing of flue gas waste heat, in this embodiment, see Figure 6-Figure 8, a post-heat exchange unit 5 for post-processing the flue gas is arranged at the lower part of the treatment furnace 1. The post-heat exchange unit 5 includes a support frame 501 fixedly arranged horizontally at the top of the post-processing area 10, and a vortex line tube 502 is fixedly arranged on the support frame 501. A third spray head 503 with an upward opening is fixedly arranged at the top of the vortex line tube 502, and a third liquid delivery pipe 504 connected to the vortex line tube 502 is arranged at the bottom of the hydraulic electric control valve 421. The hydraulic electric control valve 421 is controlled to work, and cold water is delivered from the third liquid delivery pipe 504 to the inside of the vortex line tube 502, so that the cold water is sprayed to 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-processing area 10.

[0045] The post-heat exchange unit 5 includes a V-shaped plate 505 fixedly arranged horizontally in the middle position of the post-treatment zone 10. The V-shaped plate 505 is horizontally placed in the post-treatment zone 10. A mesh plate 506 is fixedly arranged between the corner of the V-shaped plate 505 and the treatment furnace 1. At least one protrusion 507 is fixedly arranged at the bottom of the V-shaped plate 505. The protrusion 507 is a slope 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 protrusion 507. The steam is collected by the protrusion 507 and the water collecting column 508 to increase the condensation effect of the liquid. The first foam breaking net 509 is fixedly arranged horizontally 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 water mist, so that the harmful substances in the flue gas are mixed with the liquid and precipitated from the flue gas. At this time, the mixture moves downward from the mesh plate 506 through the V-shaped plate 505, is blocked by the mesh plate 506 to achieve re-mixing, and is separated from the gas and liquid for the first time through the first foam breaking net 509.

[0046] A fixed frame 510 is fixedly provided on the inner wall of the treatment furnace 1 between the middle opening of the V-shaped plate 505 and the treatment furnace 1, and a second foam breaking net 511 is fixedly provided on the side wall of the fixed frame 510. The second separation of gas and liquid is achieved by the second foam breaking net 511. A third exhaust fan 512 is fixedly provided inside the fixed frame 510, and the third exhaust fan 512 and the second exhaust fan 309 are used to extract the flue gas, providing power for the movement of the flue gas. A smoke extraction pipe 513 that runs through the side wall of the treatment furnace 1 is fixedly provided on the fixed frame 510 at the rear of the third exhaust fan 512, and the separated pure flue gas is discharged from the smoke extraction pipe 513 to the outside. A water outlet pipe 514 is connected to the inner bottom end of the post-processing area 10. The separated liquid with harmful substances is discharged from the water outlet pipe 514 to the outside for the next step of treatment.

[0047] The method of using the arc furnace flue gas waste heat recovery system of the present invention is as follows: First, when collecting the flue gas, the second exhaust fan 309 and the third exhaust fan 512 are controlled to work to provide power for the movement of the flue gas. The flue gas is drawn to the smoke delivery pipe 301 through the trumpet-shaped smoke hood 2. In this process, the first exhaust fan 308 is controlled to work, so that the smoke in the air that is not covered by the smoke hood 2 is drawn into the smoke hood 2, and at the same time, the motor 306 is controlled to work, and the driving gear 307 rotates around the ring gear 304, thereby driving the smoke hood 2 to rotate around the rotating drum 303 through the bracket 305, and then all the smoke in all positions in the air is drawn into the smoke delivery pipe 301 through the first exhaust fan 308. In this process, the motor 306 is protected by the sealing cover 310.

[0048] The liquid is sent into the water inlet chamber 406 through the water inlet pipe 409, the liquid in the water inlet chamber 406 is pumped to the cold water chamber 407 through the first pumping pump 410, and the liquid in the cold water chamber 407 is pumped to the temperature adjustment chamber 408 through the second pumping pump 411. The temperature of the liquid in the cold water chamber 407 and the temperature adjustment chamber 408 is monitored in real time through the second temperature sensor 413 and the third temperature sensor 414, so that the liquid in the cold water chamber 407 is pumped to the external refrigerator through the exchange tube 412 to reduce the temperature, and the temperature of the cold water in the temperature adjustment chamber 408 is controlled through the exchange tube 412 according to the feedback signals of the first temperature sensor 402 and the third temperature sensor 414, so as to facilitate the subsequent waste heat utilization, and avoid the waste of resources by adjusting the cold water temperature.

[0049] The third liquid pump 417 is controlled to work, and the cold water in the temperature adjustment chamber 408 is pumped to the water delivery pipe 415, and sprayed to the spiral tube 401 from the first spray head 416. Thus, heat is exchanged with the spiral tube 401, and the heat of the smoke is pre-processed. At this time, the water vapor generated when the mist water contacts the spiral tube 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. The fourth liquid pump 420 is controlled to work, so that a part of the cold water in the water delivery pipe 415 is intercepted into the distribution box 418 through the connecting pipe 419. The hydraulic electric control valve 421 is controlled to work, so that the cold water is sent from the first liquid delivery pipe 422 into the spiral tube 401, and at the same time, the cold water is sent to the inside of the smoke delivery pipe 301 on one side of the smoke hood 2 through the second liquid delivery pipe 423, so that the liquid is sent into the spiral tube 401 through the smoke delivery pipe 301 with one side high and the other side low. Water is sprayed through the first liquid delivery pipe 422 and the second liquid delivery pipe 423 to mix the liquid with the smoke, thereby prolonging the mixing time. At the same time, the inside of the smoke delivery pipe 301 and the spiral tube 401 can be cleaned to avoid corrosion by substances in the smoke.

[0050] The hydraulic electric control valve 421 is controlled to deliver cold water from the third liquid delivery pipe 504 into the interior of the spiral line tube 502, so that the cold water is sprayed to the bottom of the partition plate 8 through the third spray head 503, so that the water mist fills the upper part of the post-processing area 10. The mixture of flue gas and cold water discharged from the spiral tube 401 into the post-processing area 10 is mixed with the water mist, so that the harmful substances in the flue gas are mixed with the liquid and precipitated 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 obstruction of the mesh plate 506, and the first separation of gas and liquid is achieved through the first foam breaking net 509. In this process, the steam is collected by the protrusion 507 and the water collecting column 508 to increase the condensation effect of the liquid. The second separation of gas and liquid is achieved through the second defoaming net 511, and the separated pure smoke is discharged from the smoke pipe 513 to the outside through the smoke pipe 513, and the separated liquid with harmful substances is discharged to the outside from the water outlet pipe 514 for the next step of processing.

[0051] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by a person of ordinary skill in the field to which the invention belongs. The use of "one" or "an" and other similar words in the specification and claims of this application does not necessarily indicate a quantitative limitation. "Include" or "comprises" and other similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0052] The exemplary implementation modes of the present invention are described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations can be made to the above-mentioned specific embodiments, and various combinations of the technical features and structures proposed in the present invention can be made without exceeding the protection scope of the present invention.

Claims

1. An arc furnace flue gas waste heat recovery system, characterized in that: The invention comprises a treatment furnace (1), wherein a smoke collecting hood (2) located above an electric arc furnace is arranged on the side of the treatment furnace (1), a smoke 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 treatment furnace (1), and a post-heat exchange unit (5) capable of post-treating smoke is arranged on the lower part of the treatment furnace (1).

2. The arc furnace flue gas waste heat recovery system according to claim 1, characterized in that: The fume collection unit (3) comprises a fume delivery pipe (301) fixedly arranged at the top end of the treatment furnace (1); a support block (302) is fixedly arranged at the other end of the fume delivery pipe (301); a rotating drum (303) is coaxially fixedly arranged in the middle of the support block (302); and the top end of the fume collecting hood (2) is rotatably arranged on the rotating drum (303); The middle position of the smoke delivery pipe (301) is an inclined structure with one side higher and one side lower, and the smoke delivery pipe (301) above the smoke collecting hood (2) is higher than the smoke delivery pipe (301) above the processing furnace (1).

3. The electric arc furnace flue gas waste heat recovery system according to claim 2, characterized in that: A gear ring (304) is fixedly disposed horizontally on the top of the rotating drum (303), a bracket (305) is fixedly disposed on the top of the smoke collecting hood (2), a motor (306) is fixedly disposed vertically on the bracket (305), and a gear (307) meshing with the gear ring (304) is fixedly disposed at the output end of the motor (306); The smoke collecting hood (2) is a trumpet-shaped structure with an opening facing downward and a plurality of first exhaust fans (308) with motors (306) are arranged on the central circumference thereof; 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); the bottom end of the sealing cover (310) is in contact with the top end of the smoke collecting hood (2).

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

5. The electric arc furnace flue gas waste heat recovery system according to claim 4, characterized in that: The pre-heat exchange unit (4) comprises a spiral tube (401) fixedly arranged inside the pre-treatment zone (9); the top inlet of the spiral tube (401) penetrates the top of the top cover (6) and the end of the smoke delivery tube (301) and is fixedly arranged thereon; the bottom outlet of the spiral tube (401) penetrates the partition plate (8) and extends into the interior of the post-treatment zone (10); A first temperature sensor (402) is fixedly arranged inside the pretreatment area (9), and a drainage pipe (403) is provided at the bottom of the pretreatment area (9).

6. The electric arc furnace flue gas waste heat recovery system according to claim 5, characterized in that: The preheat exchange unit (4) further comprises a liquid storage tank (404) fixedly arranged on the side of the treatment furnace (1), wherein two isolation plates (405) are horizontally fixedly arranged inside the liquid storage tank (404), and the isolation 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) in sequence from bottom to top; The side of the water inlet chamber (406) is fixedly connected to a water inlet pipe (409) penetrating the side wall of the liquid storage tank (404); the interior of the cold water chamber (407) is fixedly provided with a first liquid pump (410) penetrating the isolation plate (405) and extending into the water inlet chamber (406); the interior of the temperature adjustment chamber (408) is fixedly provided with a second liquid pump (411) penetrating the isolation plate (405) and extending into the cold water chamber (407); the sides of the cold water chamber (407) and the temperature adjustment chamber (408) are both fixedly connected to an exchange tube (412) penetrating the side wall of the liquid storage tank (404) and connected to an external refrigerator; A second temperature sensor (413) and a third temperature sensor (414) are fixedly arranged inside the cold water chamber (407) and the temperature adjustment chamber (408), respectively.

7. The electric arc furnace flue gas waste heat recovery system according to claim 6, characterized in that: A water supply pipe (415) is provided at the top end of the temperature regulating chamber (408), the end of the water supply pipe (415) passes through the side wall of the treatment furnace (1) and the end is vertically arranged in the middle of the pretreatment zone (9), a plurality of first spray heads (416) are arranged on the circumference of the vertical portion of the water supply pipe (415), and a third liquid pump (417) is fixedly arranged at the end of the water supply pipe (415) inside the temperature regulating chamber (408); A distribution box (418) is also fixedly arranged on the side wall of the treatment furnace (1); a connecting pipe (419) is arranged on the side of the distribution box (418); an end of the connecting pipe (419) is connected to the water supply pipe (415); and a fourth liquid pump (420) is fixedly arranged on the connecting pipe (419) on the side of the distribution box (418); A hydraulically-controlled valve (421) is fixedly disposed inside the distribution box (418); a plurality of first liquid delivery pipes (422) extending into the interior of the spiral tube (401) are connected to the hydraulically-controlled valve (421); a second liquid delivery pipe (423) that can be inserted into a smoke delivery pipe (301) on one side of the smoke collecting hood (2) is connected to the hydraulically-controlled valve (421); a second spray head (424) is fixedly disposed at the other end of the second liquid delivery pipe (423).

8. The electric arc furnace flue gas waste heat recovery system according to claim 7, characterized in that: The post-heat exchange unit (5) comprises a support frame (501) fixedly arranged horizontally on the top of the post-treatment zone (10); a vortex line tube (502) is fixedly arranged on the support frame (501); a third spray head (503) with an opening facing upward is fixedly arranged on the top of the vortex line tube (502); and a third liquid delivery pipe (504) connected to the vortex line tube (502) is connected to the bottom of the hydraulic electric control valve (421).

9. The electric arc furnace flue gas waste heat recovery system according to claim 8, characterized in that: The post-heat exchange unit (5) comprises a V-shaped plate (505) fixedly arranged horizontally in the middle of the post-processing area (10); the V-shaped plate (505) is horizontally arranged in the post-processing area (10); and a mesh plate (506) is fixedly arranged between the corner of the V-shaped plate (505) and the processing furnace (1); At least one protrusion (507) is fixedly provided at the bottom of the V-shaped plate (505); the protrusion (507) is a downwardly inclined surface at the bottom; a plurality of water collecting columns (508) are fixedly provided at the bottom of the V-shaped plate (505) and the bottom of the protrusion (507); and a first foam breaking net (509) is fixedly provided horizontally at the bottom of the V-shaped plate (505).

10. The electric arc furnace flue gas waste heat recovery system according to claim 9, characterized in that: A fixing 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 fixing frame (510); a third exhaust fan (512) is fixedly arranged inside the fixing frame (510); a smoke exhaust pipe (513) penetrating the side wall of the treatment furnace (1) is fixedly arranged on the fixing frame (510) at the rear of the third exhaust fan (512); and a water outlet pipe (514) is connected to the inner bottom end of the post-treatment zone (10).

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