Apparatus for processing molten metal

• US 3,873,073 A
• Filed: 06/25/1973
• Issued: 03/25/1975
• Est. Priority Date: 06/25/1973
• Status: Expired due to Term

• Current Assignee: Jai K. Pearce, Joerg P. Baum
• Original Assignee: Jai K. Pearce, Joerg P. Baum
• Inventors: Pearce, Jai K., Baum, Joerg P.
• Primary Examiner(s): Dost, Gerald A.
• Application Number:
  US05/373,014
• Time in Patent Office: 638 Days
• Field of Search: 266/35,36P,15,16 75/60
• US Class Current: 266/89
• CPC Class Codes: C21C 5/04 Manufacture of hearth-furnace steel, e.g. Siemens-Martin steel C21C5/005 takes precedence
• CPC Class Codes: F27B 3/28 Arrangement of controlling, monitoring, alarm or the like devices

Abstract

A gas cleaning system for hearth furnaces having means for injecting process fluids below the level of molten metal and means for adjusting air intake by means of dampers in the furnace or the gas flow system or adjustable gaps between the furnace and the gas cleaning system. The furnace may be operated in the full or partial combustion mode wherein suitably located dampers control air flow to obtain the desired degree of combustion. Control means adjusts the damper or gap in the event normal air flow is disturbed. Provision is made in the system for measuring the calorific value of the off-gases and recovery of those offgases having usable fuel capacity.

Claims

1. A metallurgical process system comprising:

a metallurgical vessel for containing a quantity of molten metal to be processed, said vessel including first means for introducing reactants to said molten metal whereby substantial quantities of gases are evolved therefrom, an exit opening formed in said vessel for discharging said gases, gas disposal means for receiving said gases, second means for coupling said exit opening to said gas disposal means, said second means including third means for controlling the amount of air admitted to said gas disposal means through said second means, and fourth means respective to a change in air flow conditions into said vessel and being operable to actuate said third means to adjust the amount of air admitted to said gas disposal means, an access opening formed in said vessel, closable means operatively associated with said access opening and movable between open and closed positions for opening and closing said access opening whereby air is admitted into said vessel when said closable means is open, said fourth means being operative to sense the position of said closable means and operable to actuate said third means to decrease the amount of air admitted to the gas disposal means through said second means when said closable means is open and for increasing the amount of air admitted through said second means when said closable means is closed.

2. The system set forth in claim 1, wherein said first means includes tuyere means extending through said vessel and having an inner end disposed below the level of molten metal normally disposed within said vessel for injecting oxygen beneath the level of said metal.

3. The system set forth in claim 1 wherein said second means includes conduit means having a terminal end disposed a predetermined distance from said exit opening to provide a gap therebetween to permit the entrance of air into said second means.

4. The system set forth in claim 3 wherein said third means comprises means for adjusting the gap between said terminal end of said second means and said exit opening to adjust the quantity of air entering said gap.

5. The system set forth in claim 4 wherein said second means has an opening therein, and said third means additionally comprises means for controlling the size of said opening to control the amount of air entering said second means therethrough.

6. The system set forth in claim 1 wherein said second means has an opening formed therein, said third means comprising means for controlling the size of said opening to control the amount of air entering said second means therethrough.

7. The apparatus set forth in claim 1 wherein said fourth means comprises pressure sensing means disposed within said vessel for sensing pressure changes therein.

8. The apparatus as claimed in claim 1 wherein said fourth means comprises pressure sensing means disposed within said second means for sensing pressure changes therein.

9. The apparatus set forth in claim 1 and including selectively operable means for moving said closable means between its open and closed positions and said fourth means being coupled to said selectively operable means for actuating said third means in response to movement of said closable means by said selectively operable means.

10. The apparatus set forth in claim 1 wherein said gas disposal means comprises a gas cleaning system.

11. The apparatus as claimed in claim 10 wherein said gas cleaning system includes a first low pressure drop venturi scrubber coupled to said second means and a second venturi scrubber having an adjustable throat coupled to said first venturi separator for regulating the pressure of gas exiting the separator.

12. The apparatus set forth in claim 1 wherein said fourth means includes oxygen sensing means disposed in said second means for sensing the percentage of oxygen in the gases flowing therein, said oxygen sensing means being coupled to said third means to effect a reduction in the air entering said second means when the percentage of oxygen in the gases flowing in said second means reaches a predetermined value.

13. The system set forth in claim 1 wherein said vessel comprises an open hearth furnace having heating means provided in one end thereof, said exit opening being disposed in the other end thereof.

14. The system set forth in claim 13 wherein said first means includes tuyere means extending through said vessel and having an inner end disposed below the level of molten metal normally disposed within said vessel for injecting oxygen beneath the level of said metal.

15. The system set forth in claim 14 wherein said tuyere means includes an inner pipe means coupled to receive a reactive gas and to inject the same into said metal and a second pipe means surrounding said first pipe means for receiving a shielding fluid and for injecting the same into said metal in a substantially surrounding relation to said reactive gas.

16. The system set forth in claim 15 wherein said second means includes conduit means having a terminal end disposed a predetermined distance from said exit opening to provide a gap therebetween to permit the entrance of air into said second means.

17. The system set forth in claim 16 wherein said third means comprises means for adjusting the gap between said terminal end of said second means and said exit opening to adjust the quantity of air entering said gap.

18. The system set forth in claim 16 wherein said second means has an opening therein, and said third means additionally comprises means for controlling the size of said opening to control the amount of air entering said second means therethrough.

19. The apparatus set forth in claim 18 wherein said fourth means includes oxygen sensing means disposed in said second means for sensing the percentage of oxygen in the gases flowing therein, said oxygen sensing means being coupled to said third means to effect a reduction in the air entering said second means when the percentage of oxygen and the gases flowing in said second means reaches a predetermined value.

20. The apparatus as claimed in claim 19 wherein said gas disposal means is a gas cleaning system and said fourth means comprises pressure sensing means disposed within said second means for sensing changes in pressure within said second means.

21. The apparatus set forth in claim 19 wherein said gas disposal means is a gas cleaning system and said fourth means comprises pressure sensing means disposed within said vessel for sensing changes in pressure within said vessel.

22. The apparatus as claimed in claim 21 wherein said gas cleaning system includes a first loW pressure drop venturi separator coupled to said second means and a second venturi separator having an adjustable throat coupled to said first venturi separator for regulating the pressure of gas exiting the separator.

23. The system set forth in claim 21 wherein said third means comprises means coupled to said vessel for admitting air thereto above the level of said molten metal to effect the combustion of gases in said vessel.

24. The system set forth in claim 23 and including means associated with said third means to controlling the flow of air to said vessel.

25. The system set forth in claim 24 wherein said vessel has a vent opening for discharging gases therefrom and a gas cleaning system coupled to said vent opening.

26. The system set forth in claim 25 wherein said vessel comprises an open hearth furnace having heating means provided in at least one side thereof, said vent opening being displaced from said heating means, said first means includes tuyere means extending through said vessel and having an inner end disposed below the level of molten metal normally disposed within said vessel for injecting oxygen beneath the level of said metal, said tuyere means includes an inner pipe means coupled to receive a reactive gas and to inject the same into said metal and a second pipe means surrounding said first pipe means for receiving a shielding gas and for injecting the same into said metal in a substantially surrounding relation to said reactive gas.

27. The system set forth in claim 26 and including an opening formed in said vessel and spaced from said vent opening, said third means including means for controlling the volume of air entering said opening.

28. The apparatus set forth in claim 27 wherein said fourth means comprises pressure sensing means disposed within said vessel for sensing changes in pressure within said vessel.

29. The apparatus as claimed in claim 28 wherein said fourth means comprises pressure sensing means disposed within said second means for sensing changes in pressure within said second means.

30. The system set forth in claim 29 and including means coupling said vent opening to said gas cleaning system and having a second air admitting opening therein, and means for controlling the size of said second opening to control the amount of air entering said gas cleaning system therethrough.

31. An open hearth furnace having heating means provided in at least one side thereof, a vent opening formed in said vessel for discharging gases therefrom, said vent opening being displaced from said heating means. tuyere means extending through said vessel and having an inner end disposed below the level of molten metal normally disposed within said vessel for injecting oxygen beneath the level of said metal, said tuyere means including an inner pipe means coupled to receive a reactive gas and to inject the same into said metal and a second pipe means surrounding said first pipe means for receiving a shielding gas and for injecting the same into said metal in a substantially surrounding relation to said reactive gas, a second opening formed in said vessel and spaced from said vent opening. air control means coupled to said second opening for admitting air thereto above the level of said molten metal to effect the combustion of gases in said vessel, and including means for controlling the volume of air flow to said vessel and through said second opening. pressure sensing means disposed within one of said vessel or gas cleaning system for sensing changes in pressure within said vessel, a gas cleaning system, coupling means for coupling said vent opening to said gas cleaning system and having a second air admitting opening therein, and means for controlling the size of said second opening to control the amount of air entering said gas cleaning system therethrough, and oxygen sensing means disposed in said coupling means for sensing the percentage of oxygen in the gases flowing therein, said oxygen sensing means bEing coupled to said air control means to effect a reduction in the air entering said vessel when the percentage of oxygen in the gases flowing in said second means reaches a predetermined value.

32. The apparatus as claimed in claim 31 wherein said gas cleaning system includes a first low pressure drop venturi separator coupled to said second means and a second venturi separator having an adjustable throat coupled to said first venturi separator for regulating the pressure of gas exiting the separator.

33. The apparatus set forth in claim 1 wherein said vessel includes charging door means, said door means including at least one charging door and operating means coupled to said door for effecting movement of the same between open and closed positions, said fourth means being coupled to said charging door means and being responsive to the position thereof.

34. A metallurgical process system comprising:

a metallurgical vessel for containing a quantity of molten metal to be processed, said vessel including first means for introducing reactants to said molten metal whereby substantial quantities of gases are evolved therefrom, an exit opening formed in said vessel for discharging said gases, gas disposal means for receiving said gases, second means for coupling said exit opening to said gas disposal means, gas delivery means coupled to said vessel for delivering oxygen containing gas thereto and above the level of said molten metal for oxydizing combustable gases emanating from said molten metal, third means coupled to said air delivery means for controlling the amount of oxygen containing gas admitted to said vessel, an access opening formed in said vessel, closable means operatively associated with said access opening and movable between open and closed positions for opening and closing said access opening whereby air is admitted into said vessel when said closable means is open, fourth means operative to sense changes in the position of said closable means and operable to actuate said third means to decrease the amount of oxygen containing gas admitted to the vessel through said gas delivery means when said closable means is open and for increasing the amount of said gas admitted through said gas delivery means when said closable means is closed.

35. The system set forth in claim 34 wherein said vessel has a vent opening for discharging gases therefrom and a gas cleaning system coupled to said vent opening.

36. The system set forth in claim 35 wherein said vessel comprises an open hearth furnace having heating means provided in at least one side thereof, said vent opening being displaced from said heating means, said first means includes tuyere means extending through said vessel and having an inner end disposed below the level of molten metal normally disposed within said vessel for injecting oxygen beneath the level of said metal, said tuyere means includes an inner pipe means coupled to receive a reactive gas and to inject the same into said metal and a second pipe means surrounding said first pipe means for receiving a shielding gas and for injecting the same into said metal in a substantially surrounding relation to said reactive gas.

37. The system set forth in claim 36 wherein said gas delivery means includes an opening formed in said vessel and spaced from said vent opening, said third means including means for controlling the volume of air entering said opening.

38. The apparatus set forth in claim 37 wherein said fourth means comprises pressure sensing means disposed within said vessel for sensing changes in pressure within said vessel.

39. The apparatus as claimed in claim 37 wherein said fourth means comprises pressure sensing means disposed within said second means for sensing changes in pressure within said second means.

40. The system set forth in claim 37 wherein said fourth means includes pressure sensing means disposed in one of said vessel and second means for sensing changes iN pressure therein and including means coupling said vent opening to said gas cleaning system and having a second air admitting opening therein, and means for controlling the size of said second opening to control the amount of air entering said gas cleaning system therethrough.

41. The apparatus set forth in claim 37 wherein said fourth means includes oxygen sensing means disposed in said second means for sensing the percentage of oxygen in the gases flowing therein, said oxygen sensing means being coupled to said third means to effect a reduction in the air entering said vessel when the percentage of oxygen in the gases flowing in said second means reaches a predetermined value.

42. The apparatus as claimed in claim 41 wherein said gas cleaning system includes a first low pressure drop venturi separator coupled to said second means and a second venturi separator having an adjustable throat coupled to said first venturi separator for regulating the pressure of gas exiting the separator.

43. A metallurgical process system comprising:

a metallurgical vessel for containing a quantity of molten metal to be processed, said vessel including first means for introducing reactants to said molten metal whereby substantial quantities of gases are evolved therefrom, an exit opening formed in said vessel for discharging said gases, gas disposal means for receiving said gases, second means for coupling said exit opening to said gas disposal means, third means for controlling the amount of air admitted to one of said vessel and gas disposal means, and fourth means responsive to a change in air flow conditions into said vessel and being operable to actuage said third means to adjust the amount of air admitted to the one of said vessel and gas disposal means, an access opening formed in said vessel, closable means operatively associated with said access opening and movable between open and closed positions for opening and closing said access opening whereby air is admitted to said vessel when said closable means is open, said fourth means operative to sense changes in the position of said closable means and operable to actuate said third means to decrease the amount of air admitted to the vessel through said gas delivery, said vessel comprising an open hearth furnace having a pair of spaced apart vent openings and tuyere means below the expected level of metal in said vessel, conduit means connected to each of said vent openings, and valve means for selectively coupling one of said conduit means to a source of air and the other of said conduit means to a gas cleaning system.