Method and apparatus for metal melting, refining and processing

Abstract

An improved method and apparatus for metal melting, refining and processing, particularly adapted to steel making in an electric arc furnace. The method provides auxiliary thermal energy to the steel making process, particulate injection for the formation of slag and foamy slag, and oxygen injection for the decarburization of the melt, for the formation of foamy slag and for post combustion burning of carbon monoxide. The burner includes two injection barrels for providing finely pulverized particles and for providing either a supersonic or a subsonic primary flow of an oxidizing gas. The barrels are positioned side by side in a nozzle at the entrance of a flame shaping chamber of a fluid cooled combustion chamber. The nozzle also contains a plurality of fuel orifices for the providing pressurized fuel to the combustion chamber and a plurality of oxidizing gas orifices for providing a secondary flow of an oxidizing gas around the periphery of the nozzle. Because all of the flows of fuel, oxidizing gas and particulates pass through the flame shaping chamber, they are all substantially directed to the same location in the electric arc furnace. The directionality of the flows allows the burner to heat a localized spot of the slag with thermal energy from the oxidation of the fuel, from the oxidation of oxidizable components in the slag or the melt by the lancing of supersonic oxidizing gas, or from any combination of these. Once a spot in the slag is sufficiently heated, a flow of carbon is directed to the localized hot spot in the slag to reduce the FeO, and other oxides, in the slag to carbon monoxide and produce foamy slag. The particulate carbon introduction can be accompanied by further oxidizing gas injection before, during or after the carbon injection.

What is claimed is:  
     
         1 . An apparatus for the selective introduction of auxiliary thermal energy, an oxidizing gas or particulate matter, or combinations thereof, into a furnace, said burner comprising: 
 a combustion chamber including an input passage and a discharge passage;    a nozzle shaped to mate with said input passage of said combustion chamber;    a first conduit in fluid communication with said combustion chamber disposed in said nozzle;    a second conduit in fluid communication with said combustion chamber disposed in said nozzle;    means for selectively providing a controlled flow of particulates entrained in a carrier gas through said first conduit; and    means for selectively providing a controlled flow of pressurized oxidizing gas through said second conduit.    
     
     
         2 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 1 , which further includes: 
 at least one fuel passage;    means for selectively providing a controlled flow of pressurized fuel through said at least one fuel passage; and    said at least one fuel passage disposed in said nozzle such that said pressurized fuel combines at least partially with said oxidizing gas from said second conduit.    
     
     
         3 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 2 , which further includes: 
 at least one secondary oxidizing gas passage;    means for selectively providing a controlled flow of pressurized secondary oxidizing gas through said at least one secondary oxidizing gas passage; and    said at least one secondary oxidizing gas passage disposed in said nozzle such that said pressurized secondary oxidizing gas combines at least partially with said first oxidizing gas and fuel after they have at least partially combined.    
     
     
         4 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 1 , wherein: 
 said second conduit further includes a supersonic nozzle to accelerate said first flow of oxidizing gas above sonic velocities after the oxidizing gas pressure in said second conduit reaches a critical pressure.    
     
     
         5 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 4 , wherein: 
 said means for selectively providing a controlled flow of pressurized first oxidizing gas is adapted to vary the pressure in said second conduit to selectively provide supersonic or subsonic flows of said first oxidizing gas.    
     
     
         6 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 1 , wherein: 
 said combustion chamber in fluid cooled.    
     
     
         7 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 2 , wherein: 
 said nozzle is cooled by contact with said combustion chamber.    
     
     
         8 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 1 , wherein: 
 said combustion chamber has a flame shaping chamber disposed between said input passage and said discharge passage.    
     
     
         9 . An apparatus for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 8 , wherein: 
 said flame shaping chamber is wider at said input passage than at said discharge passage.    
     
     
         10 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace, said burner comprising: 
 a fluid cooled combustion chamber having a flame shaping chamber including an input passage and a discharge passage;    a nozzle shaped to mate with said input passage of said flame shaping chamber;    a first conduit in fluid communication with said flame shaping chamber disposed in said nozzle and directed along a first axis;    means for selectively providing a controlled flow of particulates entrained in a carrier gas through said first conduit;    a second conduit in fluid communication with said flame shaping chamber disposed in said nozzle and directed along a second axis substantially parallel to said first axis;    means for selectively providing a controlled flow of pressurized primary oxidizing gas through said second conduit;    a series of fuel passages;    means for selectively providing a controlled flow of pressurized fuel through said series of fuel passages;    said series of fuel passages disposed in said nozzle such that said pressurized fuel combines at least partially with said primary oxidizing gas from said second conduit;    a series of secondary oxidizing gas passages;    means for selectively providing a controlled flow of pressurized secondary oxidizing gas through said series of secondary oxidizing gas passages; and    said series of secondary oxidizing gas passage disposed in said nozzle such that said pressurized secondary oxidizing gas combines at least partially with said first oxidizing gas and fuel after they have at least partially combined.    
     
     
         11 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 10 , wherein: 
 said second conduit further includes a supersonic nozzle to accelerate said flow of oxidizing gas above sonic velocities after the oxidizing gas pressure in said second conduit reaches a critical pressure.    
     
     
         12 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 11 , wherein: 
 said means for selectively providing a controlled flow of pressurized first oxidizing gas is adapted to vary the pressure in said second conduit to selectively provide supersonic or subsonic flows of said first oxidizing gas.    
     
     
         13 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 10 , wherein: 
 said first and second oxidizing gas controlling means controls the total oxygen to fuel ratio to be substantially stochiometric.    
     
     
         14 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 13 , wherein said first and second oxidizing gas controlling means further comprise: 
 means for selectively controlling the total flow of said first and second oxidizing gas flows; and    means for dividing the total flow between said first oxidizing gas flow and said second oxidizing gas flow.    
     
     
         15 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 14 , wherein: 
 said means for dividing the total oxidizing gas flow divides the total flow between said first oxidizing gas flow and said second oxidizing gas flow substantially equally.    
     
     
         16 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 13 , wherein: 
 said means for dividing the total oxidizing gas flow divides the total flow between said first oxidizing gas flow and said second oxidizing gas flow based upon pressure.    
     
     
         17 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 13 , wherein: 
 said means for dividing the total oxidizing gas flow divides the total flow between said first oxidizing gas flow and said second oxidizing gas flow substantially equally when the total oxidizing gas pressure is below a critical pressure and diverts said total flow entirely to said first oxidizing gas flow when the total oxidizing gas pressure is above said critical pressure.    
     
     
         18 . A burner for the selective introduction of one or more of auxiliary thermal energy, an oxidizing gas or particulate matter into a furnace as set forth in  claim 17 , wherein: 
 said second conduit further includes a supersonic nozzle to accelerate said flow of oxidizing gas above sonic velocities after the oxidizing gas pressure in said second conduit reaches said critical pressure.    
     
     
         19 . An apparatus for the selective introduction of fluid flows into a furnace, said apparatus comprising: 
 a combustion chamber including an input passage and a discharge passage;    a first conduit in fluid communication with said input passage of said combustion chamber and adapted to provide a controlled first fluid flow of particulates entrained in a carrier gas to said input passage;    a second conduit in fluid communication with said input passage of said combustion chamber and adapted to provide a controlled second fluid flow of oxidizing gas to said input passage; and    said first and second conduits arranged such that said first and second flows are directed to substantially the same location when said first and second flows exit said discharge passage.    
     
     
         20 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said input passage is substantially circular in cross section and has an input passage diameter; and    said first conduit is substantially circular in cross section and has a diameter approximately one half of said input passage diameter.    
     
     
         21 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said input passage is substantially circular in cross section and has an input passage diameter; and    said second conduit is substantially circular in cross section and has a diameter approximately one half of said input passage diameter.    
     
     
         22 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said input passage is substantially circular in cross section and has an input passage diameter;    said first conduit is substantially circular in cross section and has a diameter approximately one half of said input passage diameter; and    said second conduit is substantially circular in cross section and has a diameter approximately one half of said input passage diameter.    
     
     
         23 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said input passage is substantially circular in cross section and has an input passage diameter;    said first conduit is substantially circular in cross section and has a first conduit diameter;    said second conduit is substantially circular in cross section and has a second conduit diameter; and    the sum of the diameters of said first and second conduits is approximately equal to said input passage diameter.    
     
     
         24 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said first conduit is adapted to provide the first fluid flow along a first axis;    said second conduit is adapted to provide the second fluid flow along a second axis; and    said first axis and said second axis are substantially parallel to each other.    
     
     
         25 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said first axis and said second axis are substantially parallel to each other and are contained in the same plane.    
     
     
         26 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said combustion chamber has a flame shaping chamber disposed between said input passage and said discharge passage.    
     
     
         27 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said combustion chamber is fluid cooled.    
     
     
         28 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , which further includes: 
 a nozzle shaped to mate with said input passage of said combustion chamber; and    wherein said first conduit is disposed in said nozzle; and    wherein said second conduit is disposed in said nozzle.    
     
     
         29 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 28 , wherein: 
 said nozzle is cooled by contact with said combustion chamber.    
     
     
         30 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , which further includes: 
 at least one fuel passage in fluid communication with said input passage;    means for selectively providing a controlled flow of pressurized fuel through said at least one fuel passage; and    said at least one fuel passage disposed in said input passage such that said pressurized fuel combines at least partially with said oxidizing gas from said second conduit.    
     
     
         31 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , which further includes: 
 at least one secondary oxidizing gas passage in fluid communication with said input passage;    means for selectively providing a controlled flow of pressurized secondary oxidizing gas through said at least one secondary oxidizing gas passage; and    said at least one secondary oxidizing gas passage disposed in said input passage such that said pressurized secondary oxidizing gas combines at least partially with said first oxidizing gas and fuel after they have at least partially combined.    
     
     
         32 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , wherein: 
 said second conduit further includes a supersonic nozzle to accelerate said oxidizing gas flow above sonic velocities after the oxidizing gas pressure in said second conduit reaches a critical pressure.    
     
     
         33 . An apparatus for the selective introduction of fluid flows into a furnace as set forth in  claim 19 , which further includes: 
 wherein said combustion chamber is fluid cooled and has a flame shaping chamber disposed between said input passage and said discharge passage;    a nozzle shaped to mate with said input passage of said combustion chamber;    wherein said input passage is substantially circular in cross section and has an input passage diameter;    wherein said first conduit is disposed in said nozzle, is substantially circular in cross section and has a diameter approximately one half of said input passage diameter; and is adapted to provide the first fluid flow along a first axis;    wherein said second conduit is disposed in said nozzle, is substantially circular in cross section and has a diameter approximately one half of said input passage diameter, and is adapted to provide the second fluid flow along a second axis;    wherein said first axis and said second axis are substantially parallel to each other and are contained in the same plane;    said second conduit further including a supersonic nozzle to accelerate said oxidizing gas flow above sonic velocities after the oxidizing gas pressure in said second conduit reaches a critical pressure;    a plurality of fuel passages in fluid communication with said input passage and disposed in said nozzle, means for selectively providing a controlled flow of pressurized fuel through said plurality of fuel passages, and said plurality of fuel passages directed such that said pressurized fuel combines at least partially with said oxidizing gas from said second conduit; and    a plurality of secondary oxidizing gas passages in fluid communication with said input passage and disposed in said nozzle, means for selectively providing a controlled flow of pressurized secondary oxidizing gas through said plurality of secondary oxidizing gas passages, and said plurality of oxidizing gas passages directed such that said pressurized secondary oxidizing gas combines at least partially with said first oxidizing gas and fuel after they have at least partially combined.