WO1984000176A1

WO1984000176A1 - Oxygen-fuel burner with lancing capability and method of producing steel

Info

Publication number: WO1984000176A1
Application number: PCT/US1983/000949
Authority: WO
Inventors: Grigory Michael Gitman
Original assignee: Cadre Corp
Priority date: 1982-06-24
Filing date: 1983-06-21
Publication date: 1984-01-19
Also published as: IT1163586B; DK91784A; ES530206A0; NO840694L; EP0112393A4; ES523585A0; IT8321767A0; EP0112393A1; CA1201372A; DK91784D0; ES8600407A1; ES8501103A1; IT8321767A1; IT8322200V0

Abstract

An oxygen-fuel burner of the rocket burner type includes a graphite burner block (11) for direct exposure to the interior of a furnace, and a cylindrical combustion chamber (115) formed through the hot face of the burner block and extending into the burner block. An oxygen supply conduit (15) delivers oxygen to the combustion chamber along the center line of the combustion chamber and fuel supply ducts (109 and 110) deliver fuel to the combustion chamber at the concave surface of the combustion chamber, whereby fuel surrounds the stream of oxygen. Excess oxygen can be supplied by the nozzle (82) to provide more oxygen than consumed by the flame, whereby the excess oxygen is preheated as it passes through the flame and can be used in a lancing process in the refining of steel.

Description

Oxygen-Fuel Burner with Lancing Capability and Method of Producing Steel

Background of the Invention

This invention relates to burners for use with electric arc furnaces and other type metal and other product melting furnaces, for high temperature heating of work products, wherein fuel and oxygen are mixed to form a high-temperature flame. The invention also relates to the method of lancing the work product.

More particularly, the invention relates to an oxy-fuel burner of the rocket burner type which includes a combustion chamber recessed into a graphite burner block, wherein the fuel is supplied to the walls of the combustion chamber for film cooling and oxygen is supplied internally of the combustion chamber, and wherein the burner block is cooled indirectly by ■transfer of heat from the combustor wall to a water cooled jacket to reduce the temperature of the burner block and the combustion chamber. The oxygen and fuel supplied to the burner can be adjusted to create a flame envelope about a high velocity stream of oxygen, to preheat the oxygen and to direct the oxygen beyond the flame toward the work product to lance the work product.

High-velocity or "rocket" burners are

f r-» ^ utilized in high temperature conditions and in conditions where it is desirable to direct a flame toward a given area. The high temperature of the flame raises the temperature of the combustor to a level that tends to rapidly deteriorate the burner. In some applications, it is desirable to cut off the supply of oxygen and fuel to the burner while the work product in the burner is still hot or is still continuing to be heated by other heat sources. Under these circumstances, the burner is subjected to heat emitted from the work product and from the other heat sources and the burner continues to deteriorate. Besides this, some furnaces have heavy splashing of molten metal materials during a melting cycle which can completely plug the burner nozzle.

In the past, various steps have been utilized to avoid the deterioration of high-temperature oxy-fuel burners in furnace atmospheres. For example, some burner designs include water cooling features, whereby water is rapidly circulated at high volumes so as to extract heat from the burner. This tends to avoid rapid oxidation and other deterioration of the burner. During the operation of some furnaces the burners are physically withdrawn from the furnace chamber when the burner is not fired so as to avoid prolonged exposure of the burner to the heat emitted within the furnace. In other furnaces the idle burners are not physically withdrawn from the furnace chamber but a supply of air is moved through the idle burner and into the furnace so that the air cools some of the exposed surfaces of the burner and protects the burner nozzle against splashing.

While some of the foregoing features have been successful in prolonging the lives of high-temperature, high-velocity burners for furnaces, certain problems have not been overcome. For example, when an idle burner is withdrawn from the furnace, a certain amount of heat and molten metal splashing is emitted from the furnace, and the burner must be designed so that it can be withdrawn. Also, when air is supplied through an idle burner to cool and protect the burner against splashing of molten material to the burner nozzle, the added air in the furnace tends to change the chemistry of processing the work product. Also, the use of water to cool directly a high-temperature combustor is somewhat hazardous in that if a crack should occur in the burner, or if water flow is interrupted, or if some other condition in the burner should occur that causes water to leak into the confines of the burner or into the furnace, an explosion will occur.

After the product in the furnace has been heated to a desired temperature, it is desirable, as in the production of steel, to lance the work product, as by directing oxygen through a conduit into the melt or toward the surface of the melt. The oxygen refines the steel by oxidation of carbon in the work product, also the oxygen reacts with other elements of the work product such as iron, sulfur and phosphorus. A significant amount of heat can be released in the area of contact between the oxygen and the molten work product.

During the typical surface lancing process a substantial amount of oxygen does not react with the melt but is exhausted from the furnace. This is because all of the oxygen is not hot enough to begin reaction when the oxygen is in the vicinity of the work product. Also, the furnace tyically is opened and an oxygen supply conduit is inserted through the opening into the furnace and the open end of the conduit is moved about the melt to deliver the oxygen across the surface of the melt. These prior art lancing procedures permit heat to escape from the furnace and require a substantial amount of time to cause the proper reaction between the oxygen and carbon of the work product.

In order to increase the percentage of utilization of oxygen and to decrease the time required for completing the lancing - process, it - would be desirable to preheat the oxygen and direct the preheated oxygen in a pattern about a large surface of the high temperature work product to contact more surface area of the work product.

When an oxygen stream is preheated and is directed against preheated scrap in a furnace which has not reached its melting point, the oxygen reacts with the scrap and heat is generated. This heat helps to melt the scrap faster, particularly at the area where the stream of oxygen is applied to the scrap. The preheating of the oxygen makes the oxidation of the preheated scrap more active and accelerates the melting process. Moreover, if preheated oxygen is used instead of unheated oxygen, the temperature of the preheated scrap does not have to be so high to achieve the desired reaction between the oxygen and the scrap. Therefore, the preheating of oxygen and applying the oxygen to the scrap in the furnace reduces the melt-down time and therefore reduces the time required for a refining cycle of the steel making process. Also, by applying activated oxygen to the preheated scrap in a furnace the final melting of the scrap and the initial refining of the work product is accomplished simultaneously.

Summary of the Invention

OMPI Briefly described, the present invention comprises a high-temperature, high-velocity oxygen-fuel burner for use with furnaces and the like which includes a high temperature-resistant burner block for direct exposure to the interior of a furnace or the like, with the burner block including a combustion chamber formed through the hot face of the burner block and extending into the burner block. In the disclosed embodiment, oxygen supply conduit means extends through

■i_Q the rear of the burner block and directs oxygen into the central portion of the combustion chamber, while fuel supply conduit means extends through the burner block and directs a major portion of the fuel into the base of the combustion chamber and about the oxygen and

•tc directs additional fuel about the concave surface of the combustion chamber, so that the fuel supplied to the concave surface causes film cooling to take place within the combustion chamber and so the oxygen is generally present at the center of the flame and the _Q fuel generally surrounds the oxygen in the flame. The introduction of oxygen and fuel in this manner provides initial mixing in the combustion chamber.

In one embodiment of the invention a plurality of cooling bores are formed from the rear ₅ surface inwardly of the burner block and are arranged parallel to one another in a circular array about the combustion chamber. Coolant supply conduits are telescopically received within the cooling bores and the supply conduits deliver liquid coolant to the ends _Q of the cooling bores adjacent the hot face of the burner block. In another embodiment a water cooling jacket extends about the burner block.

The oxygen supply conduit is movable along the length of the burner block so that the supply of oxygen can be delivered at various positions along the

OMPI length of the combustion chamber and the shape and velocity of the flame developed within and emitted from the combustion chamber can be controlled by repositioning the oxygen supply conduit. The flame emitted from the combustion chamber is a high velocity flame in which the fuel generally surrounds the oxygen. During the phase of furnace operation when the charge of metal is being melted and the temperature of the charge is being increased, the ratio of fuel and oxygen usually will be adjusted to stochiometric. When the work product has reached the desired temperature for oxygen lancing, the ratio of fuel and oxygen is changed to increase the oxygen supply. The oxygen still is surrounded by the fuel so that the flame envelope developed by the burner preheats the high velocity stream of oxygen as it is projected through the flame and into the furnace. The preheating of the excess oxygen that is not consumed in the flame activates the oxygen so that substantially all of the oxygen emitted toward the high temperature work product is likely to react with the iron, carbon, sulfur, phosphorus, etc. at the surface of the work product.

In one embodiment of the invention several of the burners are positioned at circumferentially spaced intervals about the furnace and are directed downwardly and at an angle to one side of the center of the furnace so that the flames and the activated oxygen emitted from the burners tend to swirl within the furnace and tend to disturb the melt, and the disturbance of the melt causes more uniform heat distribution within the melt and brings the previously non-oxidized portions of the melt to the surface to make direct contact with the activated oxygen. Also, the streams of activated oxygen emitted from the angled burners tend to contact substantially the entire surface of the melt to increase the speed of the refining process and to cause a high percentage of the oxygen to be utilized in the lancing process. Thus, it is an object of this invention to provide a burner for the development of a high-temperature, high-velocity flame from a mixture of oxygen and fuel and for directing the flame into a furnace or other space, wherein the burner includes a burner block that is directly exposed to the interior of the furnace, and wherein the burner block and surfaces of the combustion chamber within the burner block are continuously cooled by liquid, and wherein the surfaces of the combustion chamber of the burner block are protected by fuel film cooling.

Another object of this invention is to provide an oxygen-fuel burner that includes a graphite burner block that can be directly exposed to the interior of a hot furnace and wherein the burner block i_s internally cooled so as to prolong its life of operation.

Another object of this invention is to provide an oxygen-fuel burner of the rocket burner type which includes means for adjusting the shape of the flame emitted within and beyond the combustion chamber, and which includes a burner block that can be continuously exposed to the interior of a furnace and which includes means for cooling the burner block and for protecting the combustion chamber of the burner block.

Another object of this invention is to provide an oxygen-fuel burner which emits a high-velocity flame and which is durable and versatile in operation and inexpensive to construct and to maintain.

OMPI Another object of this invention is to provide an oxygen-fuel burner that creates a mixture of oxygen and fuel for generating a flame, with the fuel generally surrounding the oxygen, and wherein the ratio of oxygen-to-fuel can be increased so that excess oxygen located in the center of the flame is not consumed in the flame but is preheated by a surrounding flame envelope and can be directed to the surface of a work product in a furnace for oxygen lancing. Another object of this invention is to provide an improved method of refining steel with preheated oxygen, with the oxygen being preheated by transportation through a flame directed toward the work product in a furnace. Another object of this invention is to provide a method and apparatus for refining steel in a furnace in a short period of time.

Other objects, features and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a side cross-sectional view of the burner assembly.

Fig. 2 is an end cross-sectional view of the burner assembly, taken along lines 2-2 of Fig. 1.

Fig. 3 is an end cross-sectional view of the burner assembly, taken along lines 3-3 of Fig. 1. Fig. 4 is an end cross-sectional view of the burner assembly, taken along lines 4-4 of Fig. 1.

Fig. 5 is a partial side cross-sectional view, similar to Fig. 1 , but illustrating a second embodiment of the invention. Fig. 6 is a partial side cross-sectional

OMPI view, similar to Figs. 1 and 5, but illustrating a third embodiment of the invention.

Fig. 7 is a schematic plan view of the interior of a furnace, illustrating the flames developed by several of the burners of Figs. 1-6.

Detailed Description

Referring now in more detail to the drawing, in which like numerals indicate like parts throughout the several views. Fig. 1.illustrates the oxygen-fuel burner 10 which includes a burner block 11, burner block support collar 12, cooling water header 13, fuel supply conduit 14 and oxygen supply conduit 15.

In the embodiment illustrated, burner block 11 is fabricated of graphite and is substantially rectangular in shape, including a ."hot" face 18, a rear face 19, upper surface 20, lower surface 21, and side surfaces 22 and 23 (Fig. 2). A cylindrical bore 25 is formed through the central portion of hot face 18 and extends interiorally of burner block 11. Cylindrical bore 25 is threaded with helical threads 26 and includes a flat inner wall 28. The longitudinal center axis 29 of the cylindrical bore 25 is oriented at a right angle with respect to the plane of hot face 18. Burner block 11 also includes conduit bore 30 which extends through the rear portion of the burner block and which is of a smaller diameter than cylindrical bore 25, and which is also coaxial with center axis 29. Conduit bore 30 is also internally threaded with helical threads 31. Counter bore 32 is formed through rear face 19 concentrically about conduit bore 30.

A plurality of rectilinear, cylindrical cooling bores 34 are formed in burner block 11. Cooling bores 34 are arranged parallel to one another

OMPI and parallel to center axis 29 of burner block 11 and are arranged in a circular array (Fig. 2) about cylindrical bore 25. Each cooling bore 34 is internally threaded with helical threads and each bore extends from adjacent hot face 18 rearwardly through burner block 11 and opens through the rear surface 19 of the burner block.

A pair of annular fuel supply grooves 35 and 36 are formed in burner block 11, and extend radially outwardly from cylindrical bore 25, with annular groove 35 located adjacent hot face 18 of the burner block and with annular groove 36 located approximately halfway between annular groove 35 and flat inner wall 28 of cylindrical bore 25. Rectilinear grooves 38 (Fig. 2) are formed in burner block 11 and extend logitudinally with respect to the burner block, parallel to center axis 29. The rectilinear grooves 38 are formed at 90° intervals about cylindrical bore 25 and extend radially outwardly from the cylindrical bore 25 and extend longitudinally from annular fuel supply groove 35 toward counterbore 32 (Fig. 1), intersecting annular fuel supply groove 36. The rectilinear grooves 38 are undercut at 39 where they intersect conduit bore 30 and its face 33. Annular recess 40 is formed in the hot face 18 of burner block 11 and extends concentrically about cylindrical bore 25.

As illustrated in Figs. 1 and 4, burner block support collar 12 includes a rectangular frame 42 that is supported at one edge by support plate 44. Frame 42 is sized and shaped so as to fit snugly about the exterior of burner block 11, in sliding relationship therewith, so that burner block 11 abuts support plate 44. Frame 42 extends approximately one-third the distance from rear face 19 of burner block 11 toward

OMPI hot face 18. The support plate 44 extends outwardly of frame 42 and includes mounting holes 45 through which screws, bolts, or other fasteners can be inserted for mounting the burner assembly 10 to a furnace, etc. A central opening 46 is formed in support plate 44, with the internal diameter of opening 46 corresponding to the diameter of counterbore 32 of burner block 11. Inner sleeve 48 extends from support plate 44 about central opening 46, and circular flange 49 extends radially outwardly from sleeve 48. Sleeve 48 is concentric with respect to the center axis 29 of the burner assembly. Outer housing sidewalls 50 are also mounted to support plate 44, and outer flange 51 extends radially outwardly from sidewalls 50. Outer rectangular flange 51 is located in a common plane with respect to inner flange 49, and outer housing sidewalls 50 extend about inner collar 48, so that header chamber 52 is formed behind support plate 44 and between inner sleeve 48 and housing sidewalls 50. Connector openings 53 are formed through outer flange 51. In the embodiments illustrated in Figs. 1-5, inner sleeve 48 is circular and outer housing sidewalls 50 are formed in a rectangular arrangement and form a support frame about the header chamber 52.

As illustrated in Figs. 1 and 3, cooling water supply header 13 comprises a pair of spaced, parallel support plates 55 and 56, inner spacer sleeve 57 connected at its ends to support plates 55 and 56, and outer wall segments 58, 59, 60 and 61. The outer walls 58-61 are connected to one another in a rectangular arrangement and are each connected to support plates 55 and 56 so as to form cooling water header chamber 62. A water supply conduit 64 communicates with header chamber 62 through opening 65

OMFI in outer wall 61.

A plurality of cooling liquid supply openings 66 are formed in support plate 55 and are in concentric alignment with respect to the cooling liquid supply openings 47 of support plate 44 and in concentric alignment with the cooling bores 34 of burner block 11. Mounting holes 68 are formed in support plate 55, while mounting holes 69 are formed in support plate 56. Bolts or other connectors 70 connect cooling water header 13 to burner block support collar 12.

As illustrated in Fig. 1, fuel supply conduit 14 includes central conduit section 71 that extends coaxially with respect to the center axis 29 of burner block 11 and which extends through central sleeves 48 and 57 of burner block support collar 12 and cooling water header 13, with a delivery end 72 received in counterbore 32 of the burner block. A gasket 74 is positioned between the delivery end 72 and the flat face 33 of the counterbore 32. Branch supply conduit 75 intersects the central section 71 of fuel supply conduit 14. Mounting flange 76 extends radially outwardly from central section 71 , and mounting holes 78 are formed in flange 76, and the holes 78 are in alignment with the mounting holes 69 of cooling water header 13. Bolts 79 or similar connectors extend through the aligned openings 69 and 78 to mount the gas supply conduit 14 to the cooling water header 13. A similar but smaller mounting flange 80 extends radially outwardly from the rear portion of central section 71, and mounting holes 81 are formed therein.

Oxygen supply conduit 15 comprises a recilinear conduit with a nozzle 82 mounted at its delivery end, with nozzle opening 83 positioned at the center axis 29 for directing a stream of oxygen _ centrally through combustor sleeve 100.

The inner end portion adjacent nozzle 82 is externally threaded with helical threads 84 that engage the threads 31 of the conduit bore 30 of burner 5 block 11. Mounting plate 85 includes a central opening 86 that is positioned in telescoped relationship about gas supply conduit 15, and includes mounting holes 88 which are alignable with mounting holes 81 of gas supply conduit 14. Bolts 89 or similar

10 connectors connect the mounting plates 80 and 85 together. This holds oxygen supply conduit 15 in concentric relationship with respect to center axis 29 of burner block 11. The position of nozzle 82 of oxygen supply conduit 15 can be changed within the 5 cylindrical bore 25 of burner block 11 by rotating the oxygen supply conduit 15. When the conduit 15 is rotated, the engaging threads 31 and 84 move the conduit 15 and its nozzle 82 along the center axis 29 of the burner block 11, causing the nozzle to be moved 0 further into or withdrawn further from cylindrical bore 25.

As illustrated in Figs. 1, 2 and 4, the cooling bores 34 of burner block 11 are internally threaded with helical threads 90, and rectilinear water 5 outlet tubes or sleeves 91 are positioned within the bores 34. Each sleeve 91 is externally threaded, and the external threads 92 of each sleeve engage the internal threads 90 of its bore 34. The sleeves 91 extend from adjacent the hot face 18 of burner block 11 0 rearwardly through the rear face 19 of the burner block, through the cooling liquid supply openings 47 of the support plate 44 and into the header chamber 52. Nuts 92 or other connectors are threaded about the protruding end portions 94 of the sleeves 91 to make 5 sealing contact with support plate 44. Liquid supply conduits 95 are mounted in the cooling liquid supply openings 66 of cooling water header 13, and each supply conduit 95 is telescopically received within a sleeve 91 of the burner block 11. Positioning fins 96 protrude radially from the distal ends of the liquid supply conduits 95 so as to maintain the liquid supply conduits 95 in concentric, spaced relationship with respect to sleeves 91. This causes an annular space 98 to be formed between each liquid supply conduit 95 and its sleeve 91. Thus, the liquid supply conduits 95 function to move liquid from cooling water header chamber 62 telescopically through sleeves 91 to the inner end of cooling bores 34, whereupon the liquid begins to move in the opposite direction back through the annular space 98 about each liquid supply conduit 95, and the liquid then moves out of the protruding end portion 94 of sleeve 91 and into header chamber 52, where the liquid is drained from the burner assembly. Combustor sleeve 100 is positioned within cylindrical bore 25 of burner block 11. The external surface of combustor sleeve 100 creates a partition with respect to the slots 38 so that the slots become elongated fuel passageways with each slot having fuel inlet 41 between the combustor sleeve and oxygen supply conduit 15. The external surface of combustor sleeve 100 is formed with helical threads 101, and the threads 101 of the combustor sleeve engage the threads 26 of the cylindrical bore 25. The combustor sleeve is formed in three integral cylindrical sections, inner section 102, intermediate section 103, and outer section 104. The wall thicknesses of cylindrical sections 102, 103 and 104 are progressively thinner from the inner section toward the outer section, so that the diameters of the cylindrical sections 102, 103 and 104 are progressively larger from the inner section toward the outer section. This forms an annular rim 106 between inner section 102 and intermediate section 103, and a second annular rim 107 between intermediate section 103 and outer section 104. A plurality of fuel inlet ports 109 are formed in intermediate section 103 immediately adjacent annular rim 106, and a second plurality of fuel inlet ports 110 are formed in outer cylindrical section 104 immediately adjacent annular rim 107. The fuel inlet ports 109 communicate with annular fuel supply groove 36 of burner block 11, while fuel inlet ports 110 communicate with annular fuel supply groove 35. A face plate 111 is connected to the outer end portion of combustor sleeve 100 and is received within the annular recess 40 in hot face 18 of burner block 11. The face plate functions as a reflective snield and reflects radiant heat away from the burner block.

As illustrated in Fig. 5, the second disclosed embodiment 133 of the invention does not include a combustor sleeve but the burner block 134 has its bore 135 formed with cylindrical sections 136, 138, 140, 142 which are progressively larger from the inner section 136 toward outer section 142 with annular shoulders 137, 139 and 141 between the cylindrical sections. This forms a combustion chamber. The inner cylindrical section 136 merges with conduit bore 144 and four rectilinear channels 145 are formed at 90° intervals about conduit bore 144. Oxygen supply conduit 146 is threaded through bore 144 and closes the inner side of the channels to form the rectilinear channels 145 into fuel passageways which direct fuel from fuel supply conduit about oxygen supply conduit 148 into the cylindrical sections 136, 138, 140, 142 of bore 135. Oxygen is directed through

OMPI oxygen supply conduit 146 and is discharged through nozzle opening 147 into the combustion chamber along the center axis axis 149. Therefore, the fuel is supplied to the outside of the oxygen stream, and when ignited, the flame generally surrounds the oxygen.

As illustrated in Fig. 6, the burner block 150 can be formed without internally extending cooling bores, and the burner block can be formed so that it is surrounded by a cooling jacket 151 through which water circulates. In this embodiment, the cooling jacket 151 is rigidly mounted to the furnace wall and forms a cylindrical opening 152 extending at a downward angle therethrough. The cooling jacket includes a mounting flange 154 which mounts the cooling jacket to the furnace wall, and a water chamber 155 surrounds the cylindrical opening 152. A water supply conduit and a water exhaust conduit (not shown) communicate with water chamber 155 for the purpose of circulating cooling water about the burner block 150. The opening 152 is conically tapered so that it is slightly smaller inside the furnace than it is outside the furnace, and the exterior surface of the burner block 150 is also conically tapered so as to form a friction fit between the surface of the opening 152 and the external surface of the burner block. This tends to eliminate air gaps between the burner block 150 and the cooling jacket 151, and therefore provides for excellent heat transfer between these elements.

Mounting fins 158 and 159 extend at an angle upwardly from the mounting flange 154 at an angle parallel to the axial center line 160 of the burner block, and burner block support plate 16 defines slots 162 and 63 therethrough for extending about the fins 158 and 159. The fins also define slots 164 and 165, and wedges (not shown) can be extended through the slots 164 and 165 of the mounting fins behind the burner block support plate 161 so as to urge the burner block 150 into frictional contact with respect to the inside surface of the cooling jacket 151. In addition, the wedging of the burner block support plate 161 to the mounting fins 158 and 159 causes the conduits and related components extending from the burner block outward of the furnace to be supported by the burner block support plate 161 and not by the burner block 150.

Combustor sleeve 167 is similar to the combustor sleeve of Fig. 1 in that it includes three sections: large diameter section 168, intermediate diameter section 170 and small diameter section 172, with intervening rims 169 and 171. A plurality of fuel inlet ports 174 are formed in intermediate section 170 immediately adjacent annular rim 171, and a second plurality of fuel inlet ports 175 are formed in outer cylindrical section 104 immediately adjacent annular rim 169. The fuel inlet ports 174 and 175 communicate with the annular fuel supply grooves 176 and 177 of the burner block outside of the combustor sleeve 167, while the supply grooves 176 and 177 communicate with axially extending fuel supply slots 178. The combustor 167 is externally threaded and is threadedly received in the internally threaded bore 179 of the burner block.

The fuel supply conduit 180 supplies fuel to the fuel supply slots 178, and the oxygen supply conduit 181 supplies oxygen through the center bore 182 of the burner block to the central portion of the combustor 167. The open end 184 of the oxygen supply conduit 181 functions as a nozzle that is centrally located within the combustor 167, so that a stream of oxygen is generated in the combustor 167 through the nozzle opening 184. In the meantime, fuel is permitted to enter the combustor 167 through the fuel supply ports 174 and 175 as well as the openings 185 formed at the internal end of the combustor 167 at the fuel supply slots 178. Therefore, the fuel is supplied to the combustor 167 about the stream of oxygen emitted from the nozzle 184.

Operation

When the oxygen-fuel burner 10 is in operation, a supply of cooling liquid, such as water, is provided under pressure to cooling water header 13 (Fig. 1), and the water moves from header chamber 62 through the array of liquid supply conduits 95 and into the burner block 11. When the liquid moves through the open ends of the liquid supply conduits 95 adjacent the hot face 18 of the burner block, the liquid then begins its movement in the opposite direction back through the annular spaces 98 between the liquid supply conduits 95 and sleeves 91. This delivers the cooling liquid in a circular array about the combustor sleeve 100, and the movement of the cooling liquid along the sleeves 91 of the cooling bores 34 tends to extract the heat from the sleeves. The positive contact made between the threads 90 of the cooling bores 34 assures that maximum heat transfer will occur between the burner block 11 and the sleeves 91, so as to maximize the heat transfer away from the burner block. The water moving out of the sleeves 91 empties into the header chamber 52 and is drained away from the burner assembly. In the meantime, fuel and oxygen are delivered to the burner block 11. Oxygen is delivered through oxygen supply conduit 15, through nozzle 82 and out of nozzle oening 83 into the combustor sleeve 100. Fuel is delivered through gas supply conduit 14 about oxygen conduit 15, with the fuel entering the burner

OMPI block through the plurality of rectilinear grooves 38. Most of the fuel moves through the ports 41 formed through the flat inner wall 28 of cylindrical bore 25 into the combustor sleeve 100, and the rest of the fuel moves to the annular fuel supply grooves 35 and 36 where the fuel circulates around the combustor sleeve 100 and enters the combustor sleeve through the fuel inlet ports 109 and 110. With this arrangement, the oxygen is supplied centrally to the combustor sleeve 100 and is directed by nozzle opening 83 axially through the combustor sleeve 100 while the fuel is supplied peripherally about the oxygen to the combustor sleeve. Therefore, the cylindrical bore 25 of the burner block 11 and its combustor sleeve 100 form a combustion chamber 115 that opens through the hot face 18 of the burner block 11 and a flame is generated within the combustion chamber 115 and is directed outwardly of the combustion chamber, away from the burner block 11. Since the fuel is supplied about the oxygen, the flame formed from the burner tends to locate the oxygen in the center of the flame and with a portion of the fuel located primarily at the perimeter of the flame. This tends to form a non-oxidizing flame up to stochiometric flame temperature. The movement of the fuel in stages to the combustion chamber 115, first through the ports 41 at the inner end of the combustion chamber, through the fuel inlet ports 109, and through the fuel inlet ports 110 causes the flame to be developed within the combustion chamber 115. The fuel also tends to form a film on the interior surface of the combustor sleeve 100, thereby insulating the sleeve from heat of the flame. The progressive increase in diameter of the combustor sleeve 100 tends to enhance the forming of a film of fuel in the second and third cylindrical sections of the combustor sleeve 100, where the flame emitted from the burner is more intense.

The shape of the flame developed within the combustion chamber 115 can be controlled to some extent by repositioning the nozzle 82 of oxygen supply conduit 15. The nozzle 82 can be moved further into the combustion chamber 115 by rotating the oxygen supply conduit 15, so that the inner engaging threads 31 and 84 relocate the nozzle 82. As schematically indicated in Fig. 3, the supply of fluid to cooling water header chamber 52 can be controlled by valves located in the water supply conduit 64. For example, a water conduit 118 can be connected by valve 119 to water supply conduit 64, and an air conduit 120 can be connected by valve 121 to water supply conduit 64. With this arrangement the water within the system can be purged from the system by closing the water valve 119 and opening the air valve 121. This permits the rapid removal of water from the burner in a situation where the operator detects a leak or other malfunction of the burner. Additionally, the air can be used to continue the cooling of the burner.

As schematically indicated in Fig. 1, fuel supply conduit 14 is connected to fuel line 122 through valve 123, and is also connected to inert gas supply line 124 through valve 125. With this arrangement, a supply of gas or other fuel can be provided when valve 123 is open, or in the alternative, a supply of inert gas can be provided from supply line 124 through valve 125. This is desirable in a situation where the burner is not fired but is idle, and is still installed within the furnace and is exposed to the heat emitted from the work product of the furnace and to the flames emitted from other burners. The inert gas tends to form a cloud within the combustion chamber 115 so as to protect the combustion chamber from oxidation. Moreover, the supply of inert gas as opposed to oxygen through the burner in these idle conditions does not add oxygen to the furnace during the operation of other burners in the furnace. In the meantime, the coolant water can continue to circulate throughout the burner so as to continuously cool the burner and protect the burner from deterioration. In addition, the burner 10 can be operated in a low fire condition and maintained hot so as to avoid closing of the burner combustor sleeve 100 by molten metal splash from within the furnace. The supply of oxygen to oxygen supply conduit 15 is controlled by valves 127 and 128 in supply lines 129 and 130.

The operation of the oxygen-fuel burner 133 of Fig. 5 is similar to the operation of burner 10, but all of the fuel enters the bore 135 through fuel passageways 145. The fuel surrounds the oxygen emitted from oxygen supply conduit 146 and tends to flow adjacent the surfaces of the cylindrical sections 136, 138, 140 and 142, thereby functioning to form a barrier of fuel adjacent the surfaces of bore 135, resulting in film cooling of the bore. The operation of the oxygen fuel burner of

Fig. 6 is similar to the operation of the burners of Figs. 1-5, but the cooling water is utilized in the cooling jacket 151 as opposed to being applied directly to the burner block. The conically shaped burner block is urged into the conically shaped opening 152 of the cooling jacket so as to make good temperature transfer contact between these elements, with the burner block support plate 161 being supported by the mounting fins 158 and 159, with the use of wedges (not shown) inserted through the slots 164 and 165 of the mounting fins behind the mounting plate. The stream of oxygen emitted from the open nozzle 184 of the oxygen supply conduit 181 tends to move centrally through the combustor 167, and the fuel is added to the periphery of the oxygen stream by the fuel supply ports 174, 175 and fuel openings 185.

In the event that it is desirable to inject materials other than oxygen and fuel into the furnace through a burner, the flow of oxygen and fuel to the burner can be terminated and the oxygen supply conduit 181 can be disconnected from its elbow to create a through opening from outside the furnace through the burner to the inside of the furnace. This permits small diameter tubes to be inserted directly through the oxygen supply conduit into the furnace for the purpose of supplying an additive to the work product, or the for the purpose or repairing the opposite furnace wall by the flow of repair material through the conduit. when the burner is used to heat the charge of metal in a furnace, the ratio of fuel and oxygen usually will be adjusted so that the flame is as hot as possible. After the charge has been brought to a desired temperature the burner can be deactivated as described above, or the burner can be used in a lancing procedure as when completing the melting of the metal and in the refining of steel.

When used in a lancing procedure, the ratio of oxygen to fuel is increased so that the high velocity stream of oxygen is not entirely consumed in the flame, but the excess oxygen which moves through the flame is heated so that it becomes activated and is highly reactive with carbon, iron, and other elements in the melt. S illustrated in Fig. 7, several of the

CMPI burners 10 can be positioned about a furnace chamber 20 and angled to one side of the vertical centerline 201 of the chamber so that the flames and activated oxygen streams emitted from the burners are directed generally clockwise or counterclockwise about the vertical centerline. This tends to disturb the melt, by causing movement of the melt in a swirl about the vertical centerline of the furnace chamber, so that, the portions of the melt beneath the surface not previously contacted by the flames and activated oxygen streams move to the surface for contact.

The arrangement of the burners preferably is such that as much surface area of the melt as possible is to be contacted by the flame and/or the activated oxygen. The shapes of the flame and oxygen stream can be controlled by movement of the oxygen supply conduit 15 further into or further out of the combustion chamber, and the velocity of the flame and oxygen stream can be controlled by the rate of oxygen and fuel flow to the burner.

In general, the flame is directed by the burner toward the melt. When refining steel, excess oxygen is introduced to the flame so that the oxygen not consumed in the flame is heated by the surrounding flame as the oxygen approaches the steel. With this procedure the oxygen is preheated and is highly activated and readily reacts with the carbon and other elements in the work product, and a high percentage of the oxygen is consumed in the reaction. Also, the lancing process can begin when the scrap in the furnace has become hot but before the scrap has been completely melted. The reaction of the activated oxygen with the hot scrap gives off additional heat which decreases the melting time for the scrap and at the same time begins the refining process. Thus, the refining process is

OMPI accomplished rapidly.

While this invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinbefore and as defined in the appended claims.

Claims

1. A method of producing steel, and the like with preheated oxygen, in which a flame is directed toward a hot work product in a furnace chamber, characterized by the steps of moving a stream of oxygen through the flame toward the hot work product in a volume greater than that required for complete combustion of the fuel of the flame, whereby the oxygen is heated by the flame as the oxygen approaches the work product for refining the work product.

^'2. The method of Claim 1 and wherein the step of directing a flame toward the hot work product in a furnace chamber is characterized by supplying fuel in an annular pattern about the stream of oxygen so that the flame surrounds the stream of oxygen.

3. The method of Claim 1 and wherein the step of directing a flame toward a hot work product in a furnace chamber is characterized by directing a plurality of flames toward the melt at angles offset to one side about the^' vertical center of the furnace chamber to cause movement of the molten portions of the work product in the furnace chamber.

4. A method of directing preheated oxygen toward a hot work product in a furnace or the like in which a stream of oxygen is moved through a combustion chamber with the flame opening of the combustion chamber directed into the furnace, characterized by supplying fuel to the combustion chamber about the stream of oxygen for combining with the oxygen and forming a flame directed into the furnace toward the hot work product, and adjusting the amount of oxygen in the stream of oxygen to supply more oxygen than is consumed by the flame for complete combustion whereby the oxygen that is not consumed by the flame is preheated and directed toward the hot work product.

5. The method of Claim 4 further characterized by initiating the step of adjusting the amount of oxygen in the stream of oxygen to supply more oxygen than is consumed by the flame for complete combustion after the work product has been preheated but before the work product has been completely melted, and continuing the supply of excess oxygen after the work product has melted.

6. An oxygen-fuel burner comprising a burner block fabricated of high heat conductive material for directing a flame into a high temperature product melting furnace or the like with a hot face of the block extending toward the interior of the furnace, a combustion chamber formed through the hot face of and extending into said burner block, characterized by fuel supply means for supplying fluid fuel to said combustion chamber about the surface of the combustion chamber, oxygen supply means for supplying oxygen centrally into said combustion chamber, and means for introducing oxygen in said combustion chamber in excess of the stochiometric ratio so that the flame emitted by the combustion chamber does not consume all of the oxygen introduced to the combustion chamber.

7. The oxygen-fuel burner of^' Claim 6 and further characterized by said combustion chamber being approximately cylindrical with its center axis extending through the hot face of said block, and wherein said oxygen supply means comprises a nozzle positioned at the axis of said combustion chamber and movable along the center axis within said combustion chamber, and wherein said fuel supply means comprises a plurality of conduits in communication with said combustion chamber at positions about said combustion chamber.

-gU EA OMPI

8. The oxygen-fuel burner of Claim 6 further characterized by said combustion chamber being approximately cylindrical with its center axis extending through the hot face of said block, said combustion chamber being formed with at least two coaxial cylindrical sections of different diameters, with the cylindrical section of larger diameter located at the hot face of said block, and wherein said fuel supply means comprises a plurality of conduits in communication with said combustion chamber through the larger diameter section of said combustion chamber at positions adjacent said smaller diameter section of said combustion chamber, and wherein said oxygen supply means includes a nozzle opening positioned in alignment with the longitudinal axis of the cylindrical combustion chamber for emitting oxygen along the axis of the combustion chamber.

9. The oxygen-fuel burner of Claim 6 further characterized by said combustion chamber being approximately cylidrical with its center axis extending through the hot face of said block, and further including cooling conduits comprising a plurality of rectilinear cooling bores extending through said burner block parallel to the center axis of said combustion chamber and terminating adjacent said hot face and arranged in a circular array about said combustion chamber, and a cooling liquid supply conduit extending into and through a portion of each said cooling bore with an open delivery end positioned adjacent said hot face.

10. The oxygen-fuel burner of Claim 9 further characterized by metal liners positioned within said cooling bores, and said bores and said liners having mating helical threads for making positive contact between the bores and liners to enhance heat transfer between said block and said liners and the cooling liquid moved through the metal liners.

11. The oxygen-fuel burner of Claim 6 and wherein said burner block is fabricated of graphite.

12. The oxygen-fuel burner of Claim 6 further characterized by a liquid cooling system comprising a cooling jacket for mounting to a furnace and defining a conically shaped burner block opening extending therethrough, and wherein the exterior surface of said burner block corresponds in size and shape to the burner block opening and is slidably received from outside the furnace chamber in the burner block opening of the cooling jacket and can be withdrawn from the burner block opening.

13. The oxygen-fuel burner of Claim 6 and further characterized by said oxygen supply means and said combustion chamber being coaxial and forming a rectilinear opening extending through said burner block so that auxiliary elements can be projected from outside the furnace through the rectilinear opening and into the furnace for delivering additives and the like to the furnace chamber.

^'CMPI

14. An oxygen-fuel burner for an industrial furnace comprising a burner block including a hot face for direct exposure to the interior of a furnace or the like, characterized by a combustion chamber formed in said burner block and opening through the hot face of said burner block, an oxygen supply conduit extending through said burner block and interecting said combusiton chamber, a plurality of fuel supply ducts extending through said burner block and intersecting said combustion chamber uniformly about said combustion chamber, and a plurality of rectilinear cooling bores extending parallel to one another through said burner block and terminating adjacent the hot face of said burner block and positioned in a circular array about said combustion chamber, and a cooling liquid supply conduit extending in telescoped relationship into each cooling bore with an opening positioned adjacent the hot face of said burner block.

15. The oxygen-fuel burner of Claim 14 and further characterized by the combustion chamber of said burner block being approximately cylindrical and including a metal liner, said liner and said burner block including engaged helical threads.

16. The oxygen-fuel burner of Claim 15 and wherein said liner comprises at least two cylindrical sections of different internal diameters, with a larger diameter section positioned adjacent the hot face of said burner block, said larger diameter cylindrical section including fuel supply openings positioned adjacent siad smaller diameter opening and in communication with said fuel supply ducts.

OMPI

17. An oxygen-fuel burner comprising a burner block for extending into a high temperature product melting furnace or the like with one face of the block facing the interior of the furnace, a combustion chamber formed through the face of said block and extending into said block, a fuel supply conduit extending through said block and communicating with said combustion chamber, an oxygen supply conduit extending through said block and communicating with said combustion chamber, each of said fuel supply conduit and said oxygen supply conduit being in direct conduction heat transfer contact with said block, and cooling ducts extending into said block, whereby cooling fluid passes through the cooling ducts to cool the block, and the block cools the fuel supply conduit and the oxygen supply conduit.

C.Λfl _