Submerged arc furnace waste heat recycling system and method thereof

Abstract

The invention discloses a waste heat recycling system for a submerged arc furnace. The waste heat recycling system comprises a sealing protective cover and a smoke collecting box. A sealing protective cover covers the continuous casting machine to avoid smoke leakage, one end of a water vapor collecting box is connected with a steam boiler barrel through a pipeline, one end of a main steam pipeline of a waste heat boiler barrel is connected with a steam turbine generator, and one end of a liquid phase outlet pipe of the steam boiler barrel is connected with a heat exchange pipeline boiler through a circulating water pipe. A smoke outlet pipe of the smoke collecting box is connected with a submerged arc furnace waste heat boiler through a waste heat boiler inlet smoke pipe. When the waste heat boiler is used, cooling water needs to be introduced into the heat exchange pipeline boiler for heat exchange, water subjected to heat exchange is guided into the water vapor collecting box, steam-water separation can be conducted on a water vapor mixture through the steam boiler barrel, and steam is conveyed into the waste heat boiler barrel to be overheated and then used for power generation of a steam turbine generator. The separated low-temperature water can return to the heat exchange pipeline boiler for continuous heat exchange; smoke and radiant heat generated by the submerged arc furnace can be fully utilized, and the heat energy recycling rate is increased. The recycling method has the above effects.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery and utilization technology of electric arc furnaces, and in particular to a waste heat recovery and utilization system and method for electric arc furnaces. Background Technology

[0002] Electric arc furnaces generate a large amount of high-temperature flue gas and radiant heat during production, which would result in energy waste if not utilized. Although current technologies have implemented waste heat recovery and utilization of the high-temperature flue gas generated by electric arc furnaces, problems such as low utilization rate and insufficient recovery and utilization of radiant heat still exist, resulting in a significant waste of thermal energy.

[0003] Existing waste heat recovery systems for submerged arc furnaces typically heat water through pipes using high-temperature flue gas, then heat the water into high-temperature steam for use in steam turbine generators. However, this only utilizes a portion of the heat in the submerged arc furnace flue gas, resulting in a low recovery rate. Furthermore, current technologies fail to effectively collect the radiant heat generated by the submerged arc furnace itself, leading to significant waste. Therefore, there is a need to develop a novel waste heat recovery system for submerged arc furnaces that can fully utilize the high-temperature flue gas and radiant heat generated by the furnace, improve heat recovery efficiency, reduce energy waste, and achieve energy conservation and environmental protection goals. Summary of the Invention

[0004] The purpose of this application is to provide a waste heat recovery and utilization system for electric arc furnaces, which can make full use of the flue gas and radiant heat generated by the electric arc furnaces, improve the heat energy recovery and utilization rate, reduce energy waste, and achieve the goal of energy conservation and environmental protection.

[0005] To address the aforementioned technical problems, this application provides a waste heat recovery and utilization system for submerged arc furnaces, comprising:

[0006] A sealing cover installed on the outer periphery of the continuous casting machine for electric arc furnace and a smoke collection box connected to the exhaust pipe of the electric arc furnace;

[0007] The sealed cover houses a heat exchange pipe boiler located above the continuous casting machine. The upper end of the heat exchange pipe boiler penetrates the sealed cover and is connected to a steam header via a conveying pipe. One end of the steam header is connected to a steam drum via a pipe. One end of the steam drum's vapor phase outlet pipe is connected to the waste heat boiler drum at the top of the blast furnace waste heat boiler. One end of the waste heat boiler drum's main steam pipe is connected to a steam turbine generator. One end of the steam drum's liquid phase outlet pipe is connected to the heat exchange pipe boiler via a circulating water pipe.

[0008] The fumes hood at the tapping port of the electric arc furnace is connected to the exhaust pipe of the dust removal system via a flue gas conveying pipe; the sealing cover is provided with a flue gas exhaust pipe connected to the flue gas conveying pipe, and the tapping port of the electric arc furnace is provided with a molten iron exhaust pipe extending from the sealing cover to the continuous casting machine.

[0009] The smoke outlet pipe of the smoke collection box is connected to the waste heat boiler of the electric arc furnace through the inlet smoke pipe of the waste heat boiler; wherein, the continuous casting machine is located below the tapping port of the electric arc furnace.

[0010] As a preferred embodiment, a waste heat recovery and utilization system for a submerged arc furnace is provided, wherein the heat exchange pipe boiler is arranged in a serpentine pattern within the sealed cover.

[0011] As a preferred embodiment, a waste heat recovery and utilization system for a submerged arc furnace is provided, wherein the sealing cover is composed of a steel layer and a heat-insulating and wear-resistant layer.

[0012] As a preferred embodiment, a waste heat recovery and utilization system for a submerged arc furnace is provided, wherein the number of exhaust pipes of the submerged arc furnace is multiple.

[0013] As a preferred embodiment, a waste heat recovery and utilization system for a submerged arc furnace is provided, wherein the inner walls of the submerged arc furnace exhaust pipe and the waste heat boiler inlet flue are both provided with a heat-insulating and wear-resistant layer.

[0014] To address the aforementioned technical problems, this application also provides a method for recovering and utilizing waste heat from a submerged arc furnace, based on the submerged arc furnace waste heat recovery and utilization system described in any one of the above claims, comprising:

[0015] Radiant heat is collected using a sealed protective cover installed around the periphery of the continuous casting machine;

[0016] Cooling water is introduced into the heat exchange pipe boiler, which is installed inside a sealed protective cover, for heat exchange, and then introduced into the water-steam header.

[0017] The water-vapor mixture in the water-vapor collector is introduced into the steam boiler drum for steam-water separation;

[0018] The separated steam is transported to the top of the waste heat boiler of the electric arc furnace for superheating and then used to generate electricity by the steam turbine generator. The separated low-temperature water is returned to the heat exchange pipeline boiler through the circulating water pipe to continue heat exchange.

[0019] The high-temperature flue gas generated by the electric arc furnace is collected in the flue gas collection box through the flue gas pipe of the electric arc furnace. The high-temperature flue gas in the flue gas collection box is then introduced into the waste heat boiler of the electric arc furnace through the inlet flue gas pipe of the waste heat boiler for heat exchange. The flue gas after heat exchange is then treated by the dust removal system of the electric arc furnace itself.

[0020] The flue gas discharged from the sealed cover into the flue gas exhaust pipe and the flue gas in the iron tapping port hood are transported to the dust removal system of the submerged arc furnace itself through the flue gas conveying pipe for dust removal treatment.

[0021] As a preferred embodiment, a method for recovering and utilizing waste heat from a submerged arc furnace is provided, wherein the cooling water is demineralized water.

[0022] As a preferred embodiment, a method for recovering and utilizing waste heat from a submerged arc furnace includes a dust collector and a dust removal fan installed sequentially on the top of the waste heat boiler of the submerged arc furnace via an exhaust pipe.

[0023] Compared with the prior art, the present invention provides a waste heat recovery system for an electric arc furnace, including a sealing cover disposed around the periphery of a continuous casting machine and a smoke collection box connected to the exhaust pipe of the electric arc furnace; the sealing cover covers the continuous casting machine to prevent the leakage of flue gas generated during casting; a heat exchange pipe boiler is disposed inside the sealing cover and located above the continuous casting machine; the upper end of the heat exchange pipe boiler penetrates the sealing cover and is connected to a steam header through a conveying pipe; one end of the steam header is connected to a steam drum through a pipe; one end of the steam outlet pipe of the steam drum is connected to the waste heat at the top of the waste heat boiler of the electric arc furnace. The boiler drum is connected to the main steam pipe of the waste heat boiler drum, which is connected to the steam turbine generator at one end. The liquid phase outlet pipe of the steam drum is connected to the heat exchange pipeline boiler through the circulating water pipe. The smog hood at the tapping port of the electric arc furnace is connected to the exhaust pipe in the dust removal system through the flue gas conveying pipe. A flue gas exhaust pipe connected to the flue gas conveying pipe is installed on the sealing cover. A molten iron exhaust pipe extending from the sealing cover to the continuous casting machine is installed at the tapping port of the electric arc furnace. The exhaust pipe of the smog box is connected to the waste heat boiler of the electric arc furnace through the inlet smog pipe of the waste heat boiler. The continuous casting machine is located below the tapping port of the electric arc furnace. In operation, cooling water needs to be introduced into the heat exchanger boiler for heat exchange, and the water after heat exchange is guided into a steam-water header. The steam boiler drum separates the steam-water mixture in the header. The separated steam is then transported through the vapor exit pipe to the waste heat boiler drum for superheating and power generation by the turbine generator. Simultaneously, the separated low-temperature water is returned to the heat exchanger boiler through a circulating water pipe for further heat exchange. This method fully utilizes the flue gas and radiant heat generated by the submerged arc furnace, saving costs, improving heat recovery efficiency, and reducing energy waste. Furthermore, the waste heat recovery method for submerged arc furnaces provided in this application achieves the same effects as described above. Attached Figure Description

[0024] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0025] Figure 1 This is a schematic diagram of a waste heat recovery and utilization system for a submerged arc furnace provided in an embodiment of this application;

[0026] Figure 2 A flowchart of a method for recovering and utilizing waste heat from a submerged arc furnace provided in an embodiment of this application;

[0027] In the diagram: 1. Continuous casting machine; 2. Sealing cover; 3. Heat exchanger boiler; 4. Conveying pipe; 5. Steam header; 6. Pipeline; 7. Steam boiler drum; 8. Vapor outlet pipe; 9. Circulating water pipe; 10. Waste heat boiler of ferroelectric furnace; 100. Waste heat boiler drum; 101. Exhaust pipe; 102. Dust collector; 103. Dust collector fan; 11. Main steam pipeline; 12. Steam turbine generator; 13. Fertilizer flue pipe of ferroelectric furnace; 14. Smoke collection box; 15. Smoke hood at tapping point; 16. Ferrous electric furnace; 17. Inlet smoke pipe of waste heat boiler; 18. Flue gas conveying pipe; 19. Flue gas exhaust pipe; 20. Molten iron exhaust pipe. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0029] The core of this application is to provide a waste heat recovery and utilization system for electric arc furnaces, which can make full use of the flue gas and radiant heat generated by the electric arc furnaces, improve the heat energy recovery and utilization rate, reduce energy waste, and achieve the purpose of energy conservation and environmental protection.

[0030] Figure 1 This is a schematic diagram of a waste heat recovery and utilization system for a submerged arc furnace provided in an embodiment of this application. Figure 2 A flowchart of a method for recovering and utilizing waste heat from a submerged arc furnace, provided in an embodiment of this application, is shown below. Figures 1 to 2 As shown.

[0031] Example 1

[0032] A waste heat recovery system for an electric arc furnace includes a sealing cover 2 surrounding a continuous casting machine 1 of the electric arc furnace 16 and a smoke collection box 14 connected to the furnace exhaust pipe 13. The sealing cover 2 encloses the continuous casting machine 1 to prevent the leakage of flue gas generated during casting in the electric arc furnace 16. A heat exchange pipe boiler 3 is installed inside the sealing cover 2, located above the continuous casting machine 1. The upper end of the heat exchange pipe boiler 3 penetrates the sealing cover 2 and is connected to a steam and water collection box 5 via a conveying pipe 4. During operation, cooling water is introduced into the heat exchange pipe boiler 3 for heat exchange, and the water after heat exchange is then directed into the steam and water collection box 5. One end of the steam header 5 is connected to a steam boiler drum 7 via a pipe 6. One end of the steam boiler drum 7's vapor phase outlet pipe 8 is connected to the waste heat boiler drum 100 at the top of the waste heat boiler 10 of the submerged arc furnace. One end of the main steam pipe 11 of the waste heat boiler drum 100 is connected to a steam turbine generator 12. One end of the liquid phase outlet pipe of the steam boiler drum 7 is connected to the heat exchange pipeline boiler 3 via a circulating water pipe 9. The steam boiler drum 7 can separate the steam and water mixture in the steam header 5. The separated steam can be transported to the waste heat boiler drum 100 through the vapor phase outlet pipe 8 for superheating and then used to generate electricity for the steam turbine generator 12. At the same time, the separated low-temperature water can be returned to the heat exchange pipeline boiler 3 through the circulating water pipe 9 for further heat exchange; this can save costs and improve waste heat recovery efficiency.

[0033] The tapping hood 15 on the electric arc furnace 16 is connected to the exhaust pipe 101 in the dust removal system via the flue gas conveying pipe 18; the sealing cover 2 is provided with a flue gas exhaust pipe 19 connected to the flue gas conveying pipe 18, and the tapping hood on the electric arc furnace 16 is provided with a molten iron exhaust pipe 20 extending from the sealing cover 2 to the continuous casting machine 1; the dust removal system can remove dust from the flue gas in the tapping hood 15 and the flue gas collected in the sealing cover 2, and the molten iron discharged from the tapping hood on the electric arc furnace 16 can be discharged to the continuous casting machine 1 via the molten iron exhaust pipe 20. The flue gas outlet of the flue gas collection box 14 is connected to the waste heat boiler 10 of the electric arc furnace via the waste heat boiler inlet flue gas pipe 17. The high-temperature flue gas generated by the electric arc furnace 16 can be collected in the flue gas collection box 14 using the electric arc furnace exhaust pipe 13. Then, the high-temperature flue gas in the flue gas collection box 14 is re-combusted into the electric arc furnace waste heat boiler 10 through the waste heat boiler inlet flue gas pipe 17 for heat exchange. The flue gas after heat exchange can be treated by the dust removal system of the electric arc furnace 16 itself, further improving the waste heat recovery efficiency. The continuous casting machine 1 is located below the iron outlet of the electric arc furnace 16. The ferrosilicon discharged from the iron outlet of the electric arc furnace 16 falls onto the continuous casting machine 1. Figure A shows a scaled-down view of the structure consisting of the continuous casting machine 1, the sealing cover 2, and the heat exchange pipe boiler 3.

[0034] Example 2

[0035] Based on Example 1, in order to improve heat exchange efficiency, a waste heat recovery and utilization system for a submerged arc furnace can preferably have the heat exchange pipe boiler 3 arranged in a serpentine shape inside the sealed cover 2.

[0036] Based on Example 1, a waste heat recovery and utilization system for a submerged arc furnace is provided, wherein the sealing cover 2 is composed of a steel layer and a heat-insulating and wear-resistant layer to ensure good heat preservation effect.

[0037] Based on Example 1, in order to improve the flue gas efficiency of the electric arc furnace 16, a waste heat recovery and utilization system for an electric arc furnace can preferably be provided with multiple electric arc furnace flue gas pipes 13.

[0038] In this embodiment, a waste heat recovery system for a submerged arc furnace includes heat-insulating and wear-resistant layers on the inner walls of both the submerged arc furnace exhaust pipe 13 and the waste heat boiler inlet flue pipe 17. This is to prevent high-temperature flue gas from radiating heat outwards from within the submerged arc furnace exhaust pipe 13 and the waste heat boiler inlet flue pipe 17.

[0039] The waste heat recovery and utilization system for a submerged arc furnace provided in this embodiment uses a sealed cover 2 to cover the continuous casting machine 1, preventing the leakage of flue gas generated during the casting of the submerged arc furnace 16. In use, cooling water needs to be introduced into the heat exchange pipe boiler 3 for heat exchange, and the water after heat exchange is introduced into the water-steam header 5. The water-steam mixture in the water-steam header 5 can be separated into steam and water through the steam boiler drum 7. The separated steam can be transported to the waste heat boiler drum 100 through the gas phase outlet pipe 8 for superheating and then used for power generation by the steam turbine generator 12. At the same time, the separated low-temperature water can be returned to the heat exchange pipe boiler 3 through the circulating water pipe 9 to continue heat exchange. The high-temperature flue gas discharged from the submerged arc furnace exhaust pipe 13 can be collected into the smoke collection box 14, and then introduced into the submerged arc furnace waste heat boiler 10 through the waste heat boiler inlet smoke pipe 17 for heat exchange. This can make full use of the flue gas and radiant heat generated by the submerged arc furnace 16, save costs, improve the heat energy recovery and utilization rate, and reduce energy waste.

[0040] The foregoing has described in detail an embodiment of a waste heat recovery and utilization system for a submerged arc furnace. Based on the waste heat recovery and utilization system for a submerged arc furnace described in the above embodiment, the present invention also provides a method for waste heat recovery and utilization of a submerged arc furnace corresponding to the system. Since the embodiments of the method part correspond to the embodiments of the system part, the embodiments of the method part are described with reference to the embodiments of the system part, and will not be repeated here.

[0041] A method for recovering and utilizing waste heat from a submerged arc furnace, based on any one of the above-mentioned submerged arc furnace waste heat recovery and utilization systems, includes the following steps:

[0042] S1: Radiant heat is collected by a sealed cover 2 located on the outer periphery of the continuous casting machine 1.

[0043] S2: Cooling water is introduced into the heat exchange pipe boiler 3 located in the sealed cover 2 for heat exchange and then introduced into the water steam collector 5; preferably, the cooling water can be demineralized water, and demineralized water is used as the cooling medium to reduce temperature and corrosion.

[0044] S3: The water-vapor mixture in the water-vapor header 5 is introduced into the steam boiler drum 7 for steam-water separation.

[0045] S4: The separated steam is transported to the waste heat boiler drum 100 at the top of the waste heat boiler 10 of the electric arc furnace for superheating and then used for power generation by the steam turbine generator 12. The separated low-temperature water is returned to the heat exchange pipeline boiler 3 through the circulating water pipe 9 to continue heat exchange.

[0046] S5: The high-temperature flue gas generated by the electric arc furnace 16 is collected into the smoke collection box 14 by the flue pipe 13 of the electric arc furnace. The high-temperature flue gas in the smoke collection box 14 is introduced into the waste heat boiler 10 of the electric arc furnace through the waste heat boiler inlet pipe 17 for heat exchange. The flue gas after heat exchange is then treated by the dust removal system of the electric arc furnace 16 itself.

[0047] S5: The flue gas discharged from the sealing cover 2 into the flue gas exhaust pipe 19 and the flue gas in the iron tapping port hood 15 are transported to the dust removal system of the electric arc furnace 16 through the flue gas conveying pipe 18 for dust removal treatment.

[0048] In this embodiment, a method for recovering and utilizing waste heat from a submerged arc furnace includes a dust removal system comprising a dust collector 102 and a dust removal fan 103 sequentially installed on top of the submerged arc furnace waste heat boiler 10 via an exhaust pipe 101. In actual use, one end of the flue gas conveying pipe 18 is connected to the exhaust pipe 101.

[0049] This embodiment provides a method for recovering and utilizing waste heat from a submerged arc furnace. A sealed cover 2 collects radiant heat, preventing the leakage of flue gas generated during the casting of the submerged arc furnace 16. During operation, cooling water is introduced into the heat exchange pipe boiler 3 for heat exchange, and the water after heat exchange is guided into the steam-water header 5. The steam-water mixture in the steam-water header 5 is separated by the steam boiler drum 7. The separated steam is transported to the waste heat boiler drum 100 via the vapor phase outlet pipe 8 for superheating and then used to generate electricity for the steam turbine generator 12. Simultaneously, the separated low-temperature water is returned to the heat exchange pipe boiler 3 via the circulating water pipe 9 for further heat exchange. High-temperature flue gas discharged from the submerged arc furnace exhaust pipe 13 can be collected in the smoke collection box 14 and then introduced into the submerged arc furnace waste heat boiler 10 via the waste heat boiler inlet pipe 17 for heat exchange. This method fully utilizes the flue gas and radiant heat generated by the submerged arc furnace, saving costs, improving heat recovery efficiency, and reducing energy waste.

[0050] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and incorporate common knowledge or customary techniques in the art disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0051] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The embodiments of this application described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A waste heat recovery and utilization system for a submerged arc furnace, characterized in that, include: A sealing cover (2) is installed on the outer periphery of the continuous casting machine (1) of the electric arc furnace (16) and a smoke collection box (14) is connected to the exhaust pipe (13) of the electric arc furnace; The sealed cover (2) is equipped with a heat exchange pipe boiler (3) located above the continuous casting machine (1). The upper end of the heat exchange pipe boiler (3) passes through the sealed cover (2) and is connected to a steam collector (5) through a conveying pipe (4). One end of the steam collector (5) is connected to a steam drum (7) through a pipe (6). One end of the vapor phase outlet pipe (8) of the steam drum (7) is connected to the waste heat boiler drum (100) at the top of the waste heat boiler (10) of the electric arc furnace. One end of the main steam pipe (11) of the waste heat boiler drum (100) is connected to a steam turbine generator (12). One end of the liquid phase outlet pipe of the steam drum (7) is connected to the heat exchange pipe boiler (3) through a circulating water pipe (9). The fume hood (15) at the tapping port of the electric arc furnace (16) is connected to the exhaust pipe (101) in the dust removal system via the flue gas conveying pipe (18); the sealing cover (2) is provided with a flue gas exhaust pipe (19) connected to the flue gas conveying pipe (18); and the tapping port of the electric arc furnace (16) is provided with a molten iron exhaust pipe (20) extending from the sealing cover (2) to the continuous casting machine (1). The smoke outlet of the smoke collection box (14) is connected to the waste heat boiler (10) of the electric arc furnace through the waste heat boiler inlet smoke pipe (17); wherein, the continuous casting machine (1) is located below the iron outlet of the electric arc furnace (16).

2. The waste heat recovery and utilization system for a submerged arc furnace according to claim 1, characterized in that, The heat exchange pipeline boiler (3) is arranged in a serpentine shape inside the sealing cover (2).

3. The waste heat recovery and utilization system for a submerged arc furnace according to claim 1, characterized in that, The sealing cover (2) is composed of a steel layer and a heat-insulating and wear-resistant layer.

4. The waste heat recovery and utilization system for a submerged arc furnace according to claim 1, characterized in that, The number of the flue gas pipes (13) of the electric arc furnace is multiple.

5. The waste heat recovery and utilization system for a submerged arc furnace according to claim 4, characterized in that, The inner walls of the electric arc furnace exhaust pipe (13) and the waste heat boiler inlet flue pipe (17) are both provided with heat-insulating and wear-resistant layers.

6. A method for recovering and utilizing waste heat from a submerged arc furnace, based on the submerged arc furnace waste heat recovery and utilization system according to any one of claims 1-5, characterized in that, include: Radiant heat is collected by a sealed cover (2) located on the outer periphery of the continuous casting machine (1); Cooling water is introduced into the heat exchange pipe boiler (3) located in the sealed cover (2) for heat exchange and then introduced into the water steam collector (5); The water-vapor mixture in the water-vapor collector (5) is introduced into the steam boiler drum (7) for steam-water separation; The separated steam is transported to the waste heat boiler drum (100) at the top of the waste heat boiler (10) of the electric arc furnace for superheating and then used for power generation by the steam turbine generator (12). The separated low-temperature water is returned to the heat exchange pipeline boiler (3) through the circulating water pipe (9) to continue heat exchange. The feed water of the heat exchange pipeline boiler (3) comes from the feed water system of the original power generation system. The high-temperature flue gas generated by the electric arc furnace (16) is collected into the flue gas collection box (14) through the flue gas pipe (13) of the electric arc furnace. The high-temperature flue gas in the flue gas collection box (14) is introduced into the waste heat boiler (10) of the electric arc furnace through the waste heat boiler inlet pipe (17) for heat exchange. The flue gas after heat exchange is then treated by the dust removal system of the electric arc furnace (16) itself. The flue gas discharged from the sealed cover (2) into the flue gas exhaust pipe (19) and the flue gas in the iron outlet smoke hood (15) are transported to the dust removal system of the electric arc furnace (16) through the flue gas conveying pipe (18) for dust removal treatment.

7. The method for recovering and utilizing waste heat from a submerged arc furnace according to claim 6, characterized in that, The cooling water is demineralized water.

8. The method for recovering and utilizing waste heat from a submerged arc furnace according to claim 6, characterized in that, The dust removal system includes a dust collector (102) and a dust removal fan (103) installed sequentially on the top of the waste heat boiler (10) of the electric arc furnace via an exhaust pipe (101).

Images