Granulate and / or powder solid material injection lance, granulate and / or powder solid material injection system, electric arc furnace for carrying out a method of producing steel

Abstract

The utility model relates to a granular and / or powder solid material injection spray gun, a granular and / or powder solid material injection system, and an electric arc furnace for performing a method of producing steel. The spray gun comprises: a tubular housing having a central longitudinal axis and extending between a distal end and a proximal end, and along the tubular housing from the distal end, a plurality of longitudinal sections are contiguous with each other and are respectively a feed section, a transport section, and a flow-out section comprising a flow-out opening; tubular conduits arranged inside the housing and each having a longitudinally extending axis and longitudinally extending along the feed section and along the transport section, at the feed section, the tubular conduits have first input ports, the tubular conduits terminate at output ports in fluid communication with the flow-out opening, the longitudinally extending axes of the tubular conduits do not coincide with each other and are parallel to the central longitudinal axis; and a feed manifold associated with the housing at the feed section and in fluid communication with the first input ports and provided with a connection joint connected with a feed source.

Description

Technical Field

[0001] The present invention relates to a particulate and / or powder solid material injection gun for injecting solid materials in the form of granules and / or powders into a metallurgical furnace. Background Technology

[0002] In the field of electric arc furnace (EAF) iron and steel production, it is known to inject various types of fossil-derived carbon, such as coal, coke, petroleum coke, and methane, into a metal bath. Fossil-derived carbon can be introduced in various forms:

[0003] - Bulk solids (>5 cm) are introduced as furnace charge material along with waste into the furnace charge basket or other furnace charge systems, such as into a horizontal continuous furnace charge system;

[0004] - Particle solids (<3 mm), which are injected through one or more spray guns, such as movable spray guns positioned through the slag door of the furnace and / or one or more fixed spray guns installed through the side wall of the furnace.

[0005] - A gas (methane) is injected through one or more oxygen burners installed through the side wall of the furnace and is also used as a heat source for the metal bath.

[0006] In particular, systems for injecting solid materials, installed on the walls of EAF furnaces, are known, and the efficiency of these systems is crucial for optimizing iron and steel processes.

[0007] The injected carbon, in the form of granular and / or powdered solid material, combines with oxygen injected into the furnace and / or with oxides (e.g., iron oxides) present in the metal slag to produce carbon oxides. These carbon oxides allow the generation of bubbles that increase the volume of the slag, thereby creating foam on the surface of the liquid metal. This foam allows shielding against the electric arc generated by the electrodes, thereby reducing heat loss due to radiation and improving the overall efficiency of the process.

[0008] The design of the injection system and the strategy for injecting solid materials represent key aspects of carrying out the process, as well as the distribution of the injected solid materials at the slag-liquid bath interface.

[0009] In practice, solid material injection needs to involve the widest possible area, with the aim of maximizing the interaction between the solid material and the iron oxide in order to allow the iron oxide to be reduced and to maximize the conversion rate of the process.

[0010] In addition, it is necessary to control the penetration of solid materials into the metal bath in order to obtain the desired percentage of carbon in the metal bath.

[0011] For the processes of slag “foaming” and oxide reduction, penetration is optimal, particularly when the solid material reaches the separation surface between the liquid metal bath and the slag layer. Finally, the system for injecting solid materials needs to minimize the risk of the injected solid material being dragged into the furnace and flue gas system without penetrating into the slag and metal bath, thus reducing injection efficiency. This latter phenomenon is particularly relevant to very fine and lightweight materials (e.g., lime), which are unlikely to reach the metal bath and be dragged by the drawn-out flue gas flow.

[0012] The injection system installed on the wall of a known EAF furnace can be of different types:

[0013] - "Single Injector" System. Such a system consists of a single tube into which solid material in granular and / or powdered form is delivered by a carrier gas or delivery gas (usually air). This system is commonly used, but it is limited in terms of injection speed (typically <100 m / s) and therefore injection efficiency due to the required air volume and corrosion problems caused by the nature of the solid material itself.

[0014] - A "coupled" injection system, in which a "single injector" system for solid materials is coupled to a second system for injecting a high-speed, typically supersonic, jet of process gas (usually oxygen). This solution allows overcoming the limitations of the aforementioned "single injector" system where the solid material is dragged and accelerated by the high-speed jet of process gas. The coupling between the two systems typically occurs in a single device (referred to in industrial terms as an "injection point") mounted on the side wall of the furnace, and this device can be manufactured in different forms: as a "concentric tube" or as a "parallel tube."

[0015] In fact, in a "concentric tube" device, at least two concentric tubes are arranged, in which solid material is typically fed through the inner tube and gas is fed through the outer tube. These devices are effective for injection into a metal bath, but their ability to distribute solid material on the liquid bath is limited, and in the case of highly volatile solid materials, they promote the formation of high-temperature hotspots, which reduce the ability to form foamed slag.

[0016] An example of a "concentric tube" device is described in US6558614.

[0017] In a "parallel tube" apparatus, at least two tubes, i.e., two nozzles, are arranged substantially parallel to each other. One of the tubes—typically used for injecting a high-speed gas (oxygen supersonic jet)—is positioned at a higher level than the other tube, which is typically used for injecting solid material. This solution is based on the idea that the injection of solid material is facilitated by increasing its velocity through dragging due to proximity to the oxygen supersonic jet, while maintaining the material's ability to distribute itself within the slag and at the liquid-slag interface. The gas (oxygen) supersonic jet generated by the upper nozzle effectively penetrates the slag and transports the solid material injected by the lower nozzle. The transport of the solid material injected by the lower nozzle can be operated at the speed required only to pneumatically transport the solid material to the point of intersection with the gas supersonic jet.

[0018] Figure 1 shows an example of a "parallel tube" device, which illustrates a support structure S that can be fixed to the outside of the furnace sidewall and has two mounting brackets arranged on top of each other. A first spray gun L1 for injecting solid material is mounted in the lower bracket, and a second spray gun L2 for injecting a supersonic jet of oxygen is mounted in the upper bracket. Such a device forms the so-called "injection point" of the furnace.

[0019] The known solutions described above have the limitation of injecting a single type of solid material at each "injection point" at each moment (in industry terminology, as mentioned above, an "injection point" is intended as a single solid material injector that can be coupled to a supersonic oxygen injector).

[0020] This limitation is particularly pronounced when the physicochemical properties of the solid material to be injected differ. For example, different densities or particle sizes involve different delivery rates, which cannot be achieved in a single injection tube. Different chemical-physical properties (such as softening point and chemical affinity) can lead to problems with injection tube blockage.

[0021] If process requirements necessitate the injection of multiple solid materials from the same location, the common practice is to mount multiple spray guns adjacent to each other, each dedicated to a specific solid, and close to a single supersonic oxygen spray gun. Such a solution involves:

[0022] - Greater construction complexity because it requires the addition of a system for securing the spray gun to the outside of the furnace sidewalls and modifications to the cooling panels fitted to the furnace sidewalls to allow for the installation of various spray guns.

[0023] - Greater heat loss because a cooling system is required for each spray gun.

[0024] - Reduced injection efficiency. In the presence of multiple solid material injection nozzles working in conjunction with a single supersonic oxygen injection nozzle, not all solid material injection nozzles can be optimally positioned relative to the supersonic oxygen injection nozzle, which can lead to efficiency losses. For example, the solid material stream injected by one of the nozzles may not optimally reach or may not reach the supersonic jet at all, thus failing to penetrate sufficiently into the slag layer or disperse throughout the furnace due to flue gas suction.

[0025] - Reduced process efficiency. In practice, it is difficult to manage advanced configurations used for localized injection and mixing of different solid materials, configurations intended for, for example, temperature control and optimization of foam formation. In fact, different carbon materials correspond to different chemical-physical reactivity within the slag, which in some cases (e.g., in the case of materials with high fractions of volatile compounds, such as polymers—plastics, rubber—or biochar) can create concentrated temperature rises (hot spots) and cause slag liquefaction and fluidization. To mitigate such localized heating effects, it may be necessary to simultaneously inject solid materials with high melting points (e.g., lime, slag particles, metal oxides that undergo reduction within the slag itself, which is also derived from production residues such as scale, powder recovered from filters, etc.).

[0026] The aforementioned patent US6558614 provides a method for injecting solid materials through multiple concentric annular gaps (US6558614's...). Figure 7 Due to the offset arrangement of the fittings used to deliver solid material to progressively more distant inner annular gaps, this solution involves a high longitudinal dimension of the syringe. Furthermore, in order to obtain equivalent passage sections between the various annular gaps when needed, the thickness of the outermost annular gaps should gradually decrease with increasing distance from the central axis of the syringe, thus causing the flow of solid material delivered through different annular gaps to exhibit substantially different behavior.

[0027] Furthermore, as mentioned above, devices known from US6558614, in which the same syringe allows the injection of solid material along with a towed supersonic jet, do not allow changes in the relative position (distance and / or angle) between the directions of the two jets (the solid material stream and the supersonic towed gas stream), resulting in lower operational flexibility. Summary of the Invention

[0028] Therefore, there is a need for a granular and / or powdered solid material injection gun that is compact and space-saving, and that allows for the injection of various types of solid materials to reduce the number of "injection points" that can be set in a metallurgical furnace.

[0029] Another objective of this invention is to provide an injection gun that also allows for optimization of injection efficiency when the type of solid material being injected is changed.

[0030] Another objective of this invention is to provide an injection gun that can be easily installed in existing metallurgical furnaces, replacing known devices with a limited number of interventions, thereby modernizing the injection gun.

[0031] Another object of this invention is to provide a particularly easy, functional and low-cost injection gun for injecting solid materials in particulate and / or powder form into a metallurgical furnace.

[0032] These objectives created according to the present invention are achieved by manufacturing a particulate and / or powder solid material injection gun according to one aspect of the present invention for injecting solid materials in the form of granules and / or powders into a metallurgical furnace.

[0033] Other features are provided in other aspects of this utility model.

[0034] According to one aspect of the present invention, a particle and / or powder solid material injection gun is provided for injecting solid materials in the form of particles and / or powders into a metallurgical furnace, the particle and / or powder solid material injection gun comprising:

[0035] - A tubular housing having a central longitudinal axis and extending between a distal end and a proximal end that are axially opposite to each other, and along the tubular housing starting from the distal end, the following longitudinal sections are connected to each other: a feeding section for solid material in the form of granules and / or powder, a conveying section for the fed solid material, and an outflow section for the conveyed solid material, the outflow section including an outflow opening located at the proximal end;

[0036] - A plurality of different tubular conduits arranged within the housing, wherein each of the tubular conduits has a longitudinally extending axis and extends longitudinally between a first end and a second end along at least a portion of the feed section and along at least a portion of the conveying section, wherein at the feed section, the tubular conduit has at least one first inlet for a corresponding solid material flow in the form of particles and / or powder, the conveying section terminating at an outlet for a corresponding solid material flow in fluid communication with the outlet opening, wherein the longitudinally extending axes of the tubular conduits do not overlap with each other and are parallel to the central longitudinal axis; and

[0037] - At least one feed manifold for each of the tubular pipes, wherein the at least one feed manifold is associated with the housing at the feed section and is in fluid communication with the at least one first inlet of the corresponding tubular pipe, and is provided with at least one connection joint capable of being connected to the feed source of the corresponding solid material flow.

[0038] The first inlet is formed at the sidewall that demarcates the corresponding tubular conduit and extends along a direction that intersects the longitudinal extension axis of the corresponding tubular conduit and thus forms a non-zero angle with the longitudinal extension axis, or wherein the first inlet is formed at the first end of the corresponding tubular conduit and extends along a direction that is parallel to or coincides with the longitudinal extension axis of the corresponding tubular conduit.

[0039] At least one of the tubular conduits includes at least one second inlet for an auxiliary gaseous flow, wherein the second inlet is defined along a longitudinal portion of the tubular conduit extending along the feed section, and the second inlet is in fluid communication with a corresponding connecting fitting capable of being connected to a feed source for the auxiliary gaseous flow.

[0040] The second inlet is formed at the first end of the tubular conduit and extends in a direction parallel to or coincident with the longitudinal extension axis of the corresponding tubular conduit, or wherein the second inlet is formed at a sidewall that demarcates the corresponding tubular conduit and extends in a direction that intersects the longitudinal extension axis of the corresponding tubular conduit, thereby forming a non-zero angle with the longitudinal extension axis.

[0041] There is a distance between the outlet and the outflow opening of each tubular section in the tubular conduit, the distance being between 0% and 90% of the total length of at least the conveying section and the outflow section.

[0042] The particulate and / or powdered solid material injection gun includes:

[0043] - At least one encapsulation gap adapted to be traversed by an encapsulated gaseous flow, the encapsulation gap extending longitudinally along at least a portion of the feeding section and at least a portion of the conveying section, wherein in the feeding section, the encapsulation gap has at least one inlet opening for the encapsulated gaseous flow, and the encapsulation gap terminates at an outlet opening of the encapsulated gaseous flow in fluid communication with the outlet opening, wherein the encapsulation gap externally surrounds the tubular conduit, and

[0044] - At least one feed manifold, which is associated with the housing at the feed section and in fluid communication with the at least one inlet opening of the encapsulation gap, and is provided with at least one corresponding connection fitting capable of connecting to a feed source of a corresponding encapsulated gaseous flow.

[0045] The particulate and / or powdered solid material injection gun includes:

[0046] - At least one cooling gap, the cooling gap forming or accommodating a cooling circuit and extending longitudinally along at least a portion of the feed section and at least a portion of the conveying section, wherein at the feed section, the cooling circuit has at least one inlet opening and at least one outlet opening for cooling fluid flow, wherein the cooling gap externally surrounds the assembly of the tubular conduit, and

[0047] - At least one input manifold and at least one output manifold, the at least one input manifold and the at least one output manifold being associated with the housing at the feed section and in fluid communication with at least one input opening and at least one output opening of the cooling circuit, respectively, and each of the at least one input manifold and the at least one output manifold being provided with at least one corresponding connection fitting capable of being connected to the supply source of the cooling fluid and the discharge port of the cooling fluid, respectively.

[0048] Each of the tubular conduits is composed of a corresponding sector of a hollow cylindrical body arranged inside the housing and coaxial with the central longitudinal axis, each sector being demarcated by a portion of the sidewall of the hollow cylindrical body and at least one longitudinal partition wall extending inside the hollow cylindrical body.

[0049] Each of the tubular pipes is composed of a corresponding hollow cylindrical body.

[0050] Each of the tubular conduits is formed by a corresponding longitudinal hole in a solid cylindrical body.

[0051] According to another aspect of the present invention, a particulate and / or powder solid material injection system is provided for injecting solid material in the form of particles and / or powder into a metallurgical furnace, characterized in that the particulate and / or powder solid material injection system includes a particulate and / or powder solid material injection nozzle according to one or more of the foregoing aspects and at least one feed source of a flow of solid material in the form of particles and / or powder connected to the connecting joint.

[0052] For each of the tubular conduits, the granular and / or powdered solid material injection system includes a corresponding feed source connected to the corresponding connector for a respective solid material flow in granular and / or powdered form, wherein each solid material flow includes solid material in granular and / or powdered form and a conveying fluid, and wherein the feed sources differ from each other in terms of the solid material in granular and / or powdered form fed and / or in terms of the conveying fluid.

[0053] The particulate and / or powdered solid material injection system includes a supersonic process gas injector connected to the particulate and / or powdered solid material injection gun.

[0054] The particulate and / or powder solid material injection system includes at least one feed source for an auxiliary gaseous flow, the feed source of which is connected to the connecting fitting connected to the second inlet of the tubular conduit for supplying the auxiliary gaseous flow to accelerate the corresponding solid material flow in the tubular conduit.

[0055] According to another aspect of the present invention, an electric arc furnace is provided for performing a method of producing steel, characterized in that the electric arc furnace includes at least one granular and / or powdered solid material injection nozzle according to one or more of the foregoing aspects, the distal end of the granular and / or powdered solid material injection nozzle being disposed outside the electric arc furnace, and the proximal end of the granular and / or powdered solid material injection nozzle being disposed inside the electric arc furnace close to a metal bath contained in the electric arc furnace. Attached Figure Description

[0056] The features and advantages of the particulate and / or powder solid material injection gun created according to the present invention for injecting solid materials in particulate and / or powder form into a metallurgical furnace will become more apparent from the following exemplary and non-limiting description with reference to the accompanying schematic diagrams, in which:

[0057] Figure 1 is an isometric view of a "parallel tube" device for injecting solid materials in the form of granules and / or powders according to the prior art;

[0058] Figure 2 and Figure 3 Possible embodiments of the granular and / or powdered solid material injection gun created according to the present invention are shown in isometric views from different angles.

[0059] Figure 4 yes Figure 2 and Figure 3 Side view of the spray gun;

[0060] Figure 5 It is based on Figure 4The cross section of plane VV;

[0061] Figure 5A and Figure 5B Shown at magnified scale Figure 5 Details I and II;

[0062] Figure 6 Shown at magnified scale and longitudinal cross-section Figures 2 to 5 Part of the spray gun;

[0063] Figure 7 , Figure 8 , Figure 9 and Figure 9A A possible alternative embodiment of the spray gun created according to the invention is shown in a cross-section taken at the transport section of the housing;

[0064] Figure 10 A system for injecting solid and gaseous materials into an electric arc furnace is shown, the system comprising a spray gun created according to the present invention;

[0065] Figure 11 and Figure 12 An alternative configuration of a system for injecting solid and gaseous materials into an electric arc furnace is shown, the system comprising a spray gun created according to the present invention. Detailed Implementation

[0066] Referring to the accompanying drawings, a spray gun 10 is shown for injecting solid materials in granular and / or powder form into a metallurgical furnace.

[0067] Solid materials play a role in the implementation of metallurgical processes carried out in a furnace. Specifically, referring to the process of producing steel in an electric arc furnace (EAF), solid materials are, for example, carbon-containing materials—including coal, coke, petroleum coke, lime, polymeric materials (plastics, rubber), biochar—or slag particles, metal oxides, which may also be derived from production residues, such as scale or powders recovered from filters used to purify flue gas. These solid materials are used to form slag, in reduction processes, and in the composition and alloying of steel.

[0068] Solid materials are in the form of particles (<3 mm) or powder.

[0069] Solid material is fed to the spray gun 10 in the form of a mixture with a carrier fluid or conveying fluid, which is usually a carrier gas, typically air or oxygen or an inert gas, such as nitrogen or argon.

[0070] In the following description, reference will be made to a flow of solid material or simply to the solid material being fed and transported, which is intended to represent solid material in particulate and / or powder form as well as mixtures of carrier fluid or conveying fluid.

[0071] The spray gun 10 includes a tubular housing 11 having a central longitudinal axis A and extending between a distal end 110 and a proximal end 111 that are axially opposite to each other.

[0072] A cavity is defined inside the housing 11, which is located inside the spray gun 10 and extends from its distal end 110 to its proximal end 111.

[0073] Along the housing 11, starting from its distal end 110 and moving towards its proximal end 111, the following longitudinal sections are connected to each other:

[0074] – A feeding section SA for solid materials in particulate and / or powder form, i.e., a mixture of solid materials and a conveying fluid, where the conveying fluid is typically a gas, such as air.

[0075] - The conveying section ST for the solid materials being delivered, and

[0076] - The outflow section SE of the solid material being transported, the outflow section SE including the outflow opening 15 located at the proximal end 111.

[0077] The housing 11 is composed of one or more generally cylindrical tubular bodies that define or form different feed sections SA, transport sections ST and outflow sections SE.

[0078] In the embodiment shown in the accompanying drawings, the housing 11 is composed of a plurality of generally cylindrical tubular bodies, which are open at opposite ends and arranged coaxially with each other and advantageously assembled with each other in a removable manner. The tubular bodies are accordingly:

[0079] - A plurality of first tubular bodies 12a, 12b, 12c forming the feeding section SA, which are respectively a first end tubular body 12a, a first intermediate tubular body 12b and a first connecting tubular body 12c;

[0080] - The second tubular body 13 forms the transport section ST;

[0081] - The third tubular body 14 forms the outflow section SE.

[0082] The distal end 110 is normally closed; in the case depicted, the distal end 110 is closed by a bottom wall 16, which is fixed to the corresponding end of the first end tubular body 12a.

[0083] The proximal end 111 is normally open, and the outflow opening 15 is defined in the proximal end 111.

[0084] As will become more apparent below, the first tubular bodies 12a, 12b, 12c, which are sequentially connected to each other from the distal end 110 toward the proximal end 111, have progressively increasing cross-sections, and each of the first tubular bodies has a feed manifold and / or connector and fittings formed therein. The feed manifold and / or connector and fittings are used not only for feeding solid material flows, but also optionally and advantageously for other processes (gas delivery and / or gas containment) and / or functional fluids (cooling fluids).

[0085] The spray gun 10 is suitable for installation in metallurgical furnaces, particularly in existing electric arc furnaces. The spray gun 10 is typically arranged through the side wall of the furnace, and is mounted on the side wall by a suitable support that, as is known to those skilled in the art, allows for relative movement between the spray gun 10 and the furnace wall.

[0086] In use, the feed section SA, i.e., the first tubular bodies 12a, 12b, and 12c forming the feed section SA, is intended to be arranged outside the furnace, while the outflow section SE, i.e., the third tubular body 14, is intended to be arranged inside the furnace, wherein the outflow opening 15 faces the metal bath. In use, the conveying section ST, i.e., the second tubular body 13, is intended to be arranged to extend through corresponding openings formed in the side wall of the furnace, thereby forming flow channels inside and outside the furnace, with a support for the spray gun 10 arranged outside the furnace.

[0087] The end 110 of the housing 11 is defined as the "remote end" because, in use, it is away from the metal bath and outside the furnace.

[0088] The end 111 of the housing 11 is defined as the "proximal end" because, in use, it is close to the metal bath and inside the furnace.

[0089] According to the invention, the spray gun 10 includes at least two and thus a plurality of tubular conduits 17', 17'" that are separate from and different from each other, and the tubular conduits 17', 17'" are arranged inside the housing 11, or otherwise formed or defined inside the housing 11, wherein each of the tubular conduits 17', 17'" has a corresponding longitudinally extending axis B', B'" that is parallel to and does not coincide with the central longitudinal axis A, and is connected to at least one corresponding feed manifold 18', 18" of the corresponding solid material flow FS', FS'".

[0090] Each tubular conduit 17', 17” extends longitudinally between the first end 170', 170” and the second end 171', 171”, with the first end 170', 170” and the second end 171', 171” axially opposite to each other and facing the distal end 110 and the proximal end 111, respectively.

[0091] Each tubular duct 17', 17" extends longitudinally along the following portion:

[0092] - Extending longitudinally along at least a portion of the feed section SA, each tubular conduit 17', 17" has at least one first inlet 172', 172" for the corresponding solid material flow FS', FS" in the form of granules and / or powder, and

[0093] - Extending longitudinally along at least a portion of the transport section ST, it terminates at an outlet 173', 173" for the corresponding solid material flow. The outlet 173', 173" is in fluid communication with the outflow opening 15.

[0094] The spray gun 10 also includes at least one feed manifold 18', 18" for each of the tubular pipes 17', 17" . Each tubular pipe 17', 17" is connected to at least one corresponding feed manifold 18', 18" that is specifically matched to the corresponding tubular pipe and is therefore separate and different from the feed manifolds 18', 18" connected to the remaining tubular pipes 17', 17" for feeding the corresponding solid material flow into the tubular pipe 17', 17" .

[0095] Each feed manifold 18', 18” is associated with the housing 11 at the feed section SA and is in fluid communication with the first inlet 172', 172” of the corresponding tubular conduit 17', 17”.

[0096] Each feed manifold 18', 18" is provided with at least one connection joint 19', 19" and the connection joint 19', 19" is adapted to be connected to the corresponding feed source S1, S2...Sn of the corresponding solid material flow FS', FS (a mixture of gas and solid material in particulate and / or powder form).

[0097] As mentioned above, the tubular conduits 17', 17" are arranged within the housing 11, or otherwise formed or defined within the housing 11. As further detailed below, they can be manufactured in a variety of different ways, which are interchangeable and non-limiting. Thus, for example, their structure can be non-uniform along their length, with one section of the structure formed or defined by a tubular or cylindrical body or a portion of a tubular or cylindrical body arranged inside the housing 11, and / or with another section of the structure formed or defined by a portion of the same housing 11, i.e., a portion of a first tubular body 12a, 12b, 12c and / or a second tubular body 13 and / or a third tubular body 14, wherein fittings and / or gaskets suitable for ensuring their continuity are inserted. Furthermore, the tubular conduits 17', 17" can have circular, polygonal, or mixed cross-sections, and they also differ from each other in shape and / or size.

[0098] As mentioned above and shown in the accompanying drawings, the longitudinal extension axes B' and B' of the tubular pipes 17' and 17'' are parallel to each other and do not coincide; furthermore, they are parallel to and preferably do not coincide with the central longitudinal axis A of the housing 11, i.e., the central longitudinal axis A of the spray gun 10.

[0099] In a plane orthogonal to the central longitudinal axis A, the longitudinal extension axes B' and B' of the tubular pipes 17' and 17'" are arranged, for example, to be spaced apart from each other along a circumference concentric with the central longitudinal axis A.

[0100] The longitudinal extension axes B' and B' of the tubular ducts 17' and 17" are not necessarily axes of symmetry.

[0101] The tubular pipes 17', 17" divide the interior of the housing 11, i.e., the interior of the spray gun 10, into a plurality of separate and distinct longitudinal chambers. Each longitudinal chamber can be traversed by a corresponding solid material flow FS', FS" which is supplied to the longitudinal chamber by a corresponding feed manifold 18', 18" which is separate and distinct from the feed manifolds 18', 18" that connect to the other tubular pipes 17', 17" respectively. The number of tubular pipes 17', 17" that define the longitudinal chambers is equal to the number of feed manifolds 18', 18" with corresponding connectors 19', 19"; each tubular pipe 17', 17" is connected to the corresponding feed manifold 18', 18" in a one-to-one correspondence via the corresponding connector 19', 19" respectively.

[0102] Therefore, solid material flows that are the same or different from each other, for example, in terms of the type of solid material and / or the type of fluid being transported and / or the characteristics of the delivery flow (flow rate, velocity, temperature, pressure, etc.), can be delivered simultaneously or at a delayed time by the same single spray gun 10.

[0103] Thus, each longitudinal chamber within the cavity of each tubular conduit 17', 17" (i.e., the cavity within the spray gun 10) is divided by its own solid material flow, which is optimized according to the chemical-physical characteristics of a defined "family" of solid or similar solid materials. Providing corresponding feed manifolds 18', 18" separate and independent from other tubular conduits in each of the tubular conduits 17', 17" allows for the generation of solid material flows FS', FS" with different hydrodynamic characteristics (for flow rate, velocity, temperature, pressure, etc.) optimized for conveying different solid materials. Therefore, two or more different solid materials can be injected by the same spray gun 10, thus forming a single "injection point" in the furnace. Depending on process requirements, the injection of two or more solid materials, or the activation of two (or more) solid material flows, can occur simultaneously or with a delay.

[0104] In a possible implementation, as shown in the accompanying drawings, first inlets 172', 172" are formed on the sidewalls that demarcate the respective tubular conduits 17', 17" and extend along directions C', C" intersecting the longitudinal extension axes B', B" of the respective tubular conduits 17', 17" with a non-zero angle α to guide the flow of solid material injected through the first inlets 172', 172" toward the outlets 173', 173" . The angle α is different from 90° and 180°.

[0105] In a possible alternative embodiment not shown in the accompanying drawings, first inlets 172', 172” are formed at the first ends 170', 170” of the respective tubular conduits 17', 17” and extend along directions C', C” parallel to or coincident with the respective longitudinal extension axes B', B”.

[0106] Each feed manifold 18', 18” is composed of a tubular element coaxial with the corresponding first inlet 172', 172”.

[0107] Optionally, at least one of the tubular conduits 17', 17" or preferably each tubular conduit includes at least one second inlet 174', 174" for the auxiliary gaseous flow FG', FG"; the second inlet 174', 174" is defined along a longitudinal portion of the tubular conduit 17', 17" extending along the feed section SA, and at least one second inlet 174', 174" is in fluid communication with a corresponding connecting fitting 20', 20" suitable for connection with the feed source G1, G2...Gn of the auxiliary gaseous flow.

[0108] Preferably, as shown in the accompanying drawings, the second inlets 174', 174” are formed at the first ends 170', 170” of the respective tubular conduits 17', 17”, and extend along directions D', D” parallel to or coincident with the longitudinal extension axes B', B” of the respective tubular conduits 17', 17”.

[0109] According to an alternative embodiment not shown, the second inlets 174', 174” are obtained at the sidewalls that delineate the respective tubular conduits 17', 17”, and extend along directions D', D” that intersect the longitudinal extension axes B', B” of the respective tubular conduits 17', 17”, with directions D', D” forming a non-zero angle with the longitudinal extension axes B', B” other than 90° or 180°.

[0110] As shown in the accompanying drawings, if the first inlets 172', 172" of the corresponding feed manifolds 18', 18" are formed along extension directions C', C" intersecting the corresponding longitudinal extension axes B', B" at the sidewalls demarcating the corresponding tubular pipes 17', 17", then the second inlets 174', 174" are preferably formed at the first ends 170', 170" of the corresponding tubular pipes 17', 17" and extend along directions D', D" parallel to or coinciding with the longitudinal extension axes B', B" of the corresponding tubular pipes 17', 17" . In the illustrated embodiment, the second inlets 174', 174" are formed at the bottom wall 16.

[0111] Conversely, if the first inlet 172', 172" of the corresponding feed manifold 18', 18" is formed at the first end 170', 170" of the corresponding tubular pipe 17', 17" along an extension direction C', C" parallel to or coincident with the corresponding longitudinal extension axis B', B", then the second inlet 174', 174" is preferably formed at the sidewall that demarcates the corresponding tubular pipe 17', 17" and extends along a direction D', D" intersecting with the longitudinal extension axis B', B" of the corresponding tubular pipe 17', 17".

[0112] The auxiliary gaseous flows FG', FG” injected through the second inlet ports 174', 174” typically have a high velocity (e.g., supersonic) and serve to accelerate the corresponding solid material flows FS', FS” injected through the first inlet ports 172', 172”, and may help align the solid material flows FS', FS” parallel to the central longitudinal axis A. The auxiliary gaseous flows FG', FG” may include air, nitrogen, oxygen, argon, or other gases known in the art.

[0113] There is a distance H between the outlet 173', 173" of each tubular conduit 17', 17" and the outflow opening 15 of the casing 11. Figure 5A The distance H is between 0% and 90% of the total length of at least the transport section ST and the outflow section SE, preferably between 0% and 50%, even more preferably between 0% and 30%, or between 0% and 90% of the total length of the transport section ST, the outflow section SE and the feed section SA downstream of the first inlet 172', 172”, preferably between 0% and 50%, even more preferably between 0% and 30%.

[0114] In other words, the outlet 173', 173" of each of the tubular pipes 17', 17" is located at the outlet opening 15 or at a distance H behind the outlet opening 15, as defined above.

[0115] Optionally, the spray gun 10 also includes:

[0116] - At least one encapsulation gap 21, adapted to be traversed by an encapsulated gaseous flow, which encapsulates the tubular conduit 17', 17'' externally, either individually or as a whole, and the encapsulation gap 21 extends longitudinally along at least a portion of the feed section SA, where the encapsulation gap 21 has at least one inlet opening 210 for encapsulating the gaseous flow, and the encapsulation gap 21 extends along at least a portion of the conveying section ST, terminating at an outlet opening 211 for encapsulating the gaseous flow, the outlet opening 211 being in fluid communication with an outlet opening 15, and

[0117] - At least one feed manifold 22, which is associated with or defined in the housing 11 at the feed section SA or otherwise formed in the housing 11 and is in fluid communication with the inlet opening 210 of the cover gap 21, and is provided with at least one corresponding connector 220 adapted to be connected to the feed source GC of the corresponding cover gas flow.

[0118] Encapsulated gaseous flow (industry term "encapsulated" gaseous flow) is intended to refer to gaseous flows such as air, oxygen, methane, hydrogen, or mixtures thereof, used to form:

[0119] - Used to cover the edges of the solid material stream leaving the spray gun 10, and

[0120] - Low-density combustion zone,

[0121] Both aim to enhance the jet velocity that sustains the flow of solid material.

[0122] Preferably, the covering gap 21 can have an annular edge shape, preferably a circular edge shape, in a section orthogonal to the central longitudinal axis A, and the covering gap 21 surrounds the tubular pipe 17', 17” assembly on the outside.

[0123] In a possible implementation, the spray gun 10 includes at least a first pair of tubular walls, preferably cylindrical, arranged inside the housing 11 and coaxial with the central longitudinal axis A, forming a covering gap 21 between the first pair of tubular walls, the covering gap 21 externally surrounding the tubular conduits 17', 17" assembly. As will become more apparent below, the tubular walls in the first pair of tubular walls, or the walls that otherwise define the covering gap 21, may be formed by walls of different components or by walls of components forming other elements of the spray gun 10, particularly including those components that at least partially define or form the sidewalls of the tubular conduits themselves 17', 17" or surround the tubular conduits themselves 17', 17"

[0124] Optionally, the spray gun 10 includes:

[0125] - At least one cooling gap 23, which externally surrounds the tubular conduits 17', 17" and forms or accommodates a cooling circuit, and extends longitudinally along at least a portion of the feed section SA and at least a portion of the transport section ST, wherein the cooling circuit has at least one inlet opening 230 and at least one outlet opening 231 for cooling fluid flow; and

[0126] - At least one input manifold 24 and at least one output manifold 25, which are associated with or defined in or otherwise formed in the housing 11 at the feed section SA, and are in fluid communication with the input opening 230 and the output opening 231 of the cooling circuit respectively. Each of the input manifold 24 and the output manifold 25 is provided with at least one corresponding connecting fitting 240, 250, which is adapted to connect to a source of cooling fluid and a discharge port of cooling fluid, or to an external circuit CF in which cooling fluid flows and is only schematically depicted.

[0127] Preferably, the cooling gap 23 may have an annular edge shape in a section orthogonal to the central longitudinal axis A, preferably a circular edge shape. The cooling gap 23 surrounds the tubular pipe 17', 17" assembly on the outside. The cooling gap 23 is divided into two circular edges on the inside, wherein the innermost circular edge defines the outflow path of the cooling fluid and the outermost circular edge defines the return path of the cooling fluid.

[0128] In a preferred embodiment, the spray gun 10 includes at least a second pair of tubular walls arranged inside the housing 11 and coaxial with the central longitudinal axis A, forming a cooling gap 23 between the second pair of tubular walls, the cooling gap 23 surrounding the tubular pipes 17', 17" assembly externally.

[0129] As will become more apparent below, the tubular wall in the second pair of tubular walls, or the wall that otherwise defines the cooling gap 23, may be formed by the wall of different components or by the wall of components forming other elements of the spray gun 10, particularly including those components that define or at least partially form the tubular conduits 17', 17" themselves, or form the housing 11, or form the wall of the first pair of tubular walls that demarcates the covering gap 21 (if provided).

[0130] In the latter case, the cooling gap 23 advantageously surrounds and covers the gap 21 on the outside.

[0131] The cooling fluid can be, for example, water.

[0132] The tubular pipes 17', 17” can be made in various ways, at least for a portion of their length, and particularly for portions of their length extending along the delivery section ST and along the outflow section SE, and for the flow channels downstream of the respective first inlets 172', 172” in the feed section SA:

[0133] - For example Figure 5 , Figure 6 and Figure 7 As shown, each of the tubular conduits 17', 17'' is formed by a corresponding sector of a hollow cylindrical body 26 arranged inside the housing 11 and coaxial with the central longitudinal axis A. Each such sector is defined by a portion of a sidewall of the hollow cylindrical body 26 and at least one longitudinal partition wall 27 located inside the hollow cylindrical body 26. The partition wall 27 is fixed to the inner surface of the hollow cylindrical body 26 and is shaped to divide the internal volume of the hollow cylindrical body 26 into a plurality of longitudinal chambers, each of which forms a corresponding tubular conduit 17', 17''. Figure 5 and Figure 6 In the hollow cylindrical body 26, a planar partition wall 27 is provided, which divides the internal volume into two sectors, forming two corresponding tubular pipes 17' and 17''. For example, from... Figure 5 It can be noted that at the feeding section SA, the partition wall 27 extends to the outside of the hollow cylindrical body 26 to engage with the bottom wall 16. Figure 7 The implementation shown is different Figure 5 and Figure 6The embodiment shown is characterized in that the partition wall 27' has three radial planes that divide the internal volume of the hollow cylindrical body 26 into three sectors, which have a circular sector shape in cross-section and form three tubular channels 17', 17" and 17'''. The hollow cylindrical body 26 may be composed of a single body or multiple bodies joined together.

[0134] - For example Figure 8 As shown, each of the tubular conduits 17', 17”, 17''' is formed by a corresponding longitudinal hole in the solid cylindrical body 28.

[0135] - For example Figure 9 As shown, each of the tubular pipes 17', 17”, 17''' is composed of a corresponding hollow cylindrical body 29', 29”, 29''', in Figure 9A In an alternative illustrative embodiment, the hollow cylindrical bodies 29', 29”, and 29''' can be sequentially housed within another outer hollow cylindrical body 30.

[0136] In any case, each of the tubular conduits 17', 17”, 17''' is provided with a separate and independent corresponding feed manifold from the other tubular conduits for feeding the corresponding solid material into the tubular conduit.

[0137] Refer to Figure 1 to Figure 6 The illustrated embodiment includes two tubular conduits 17', 17''. Each of these tubular conduits 17', 17'' is formed by a corresponding sector of a hollow cylindrical body 26 arranged inside the housing 11 and coaxial with the central longitudinal axis A. Each such sector is defined by a portion of the sidewall of the hollow cylindrical body 26 and a longitudinal partition wall 27 located inside the hollow cylindrical body 26. The partition wall 27 is fixed to the inner surface of the hollow cylindrical body 26 and is shaped to divide the internal volume of the hollow cylindrical body 26 into two longitudinal chambers, each of which forms a corresponding tubular conduit 17', 17''. The hollow cylindrical body 26 extends between a first end downstream of the first inlet 172', 172'' and a second end upstream of the outlet 15. The partition wall 27 extends to the outside of the first end of the hollow cylindrical body 26 to engage with the bottom wall 16 and terminates upstream of the second end of the hollow cylindrical body 26. The outlets 173', 173" are spaced apart from the outflow opening 15 by a non-zero distance H, but as mentioned above, this distance H can be zero.

[0138] First input ports 172', 172” are formed in the first end tubular body 12a, which is connected to the hollow cylindrical body 26. Second input ports 174', 174” with corresponding connecting fittings 20', 20” are located on the bottom wall 16.

[0139] A covering gap 21 is provided, defined by a pair of first tubular walls, which are correspondingly formed by the outer sidewall of a hollow cylindrical body 26 and the inner sidewall of another hollow cylindrical body 31, which is arranged coaxially with the central longitudinal axis A inside the housing 11 and outside the hollow cylindrical body 26. The other hollow cylindrical body 31 is joined at one end to a feed manifold 22 covering the gaseous fluid and at the opposite end to a third tubular body 14. The feed manifold 22 is formed by an annular chamber. In the depicted form, such an annular chamber is defined by the hollow cylindrical body 26 and the first intermediate tubular body 12b, with a connecting fitting 220 formed at the first intermediate tubular body 12b.

[0140] After flowing through the coating gap 21, the coating gaseous flow flows into the interior of the furnace through the output opening 211, thereby promoting and improving the transport of the injected solid material toward the metal bath.

[0141] A cooling gap 23 is provided, surrounding and covering the external gap 21. The cooling gap 23 is defined by a pair of second tubular walls, which are correspondingly formed by the outer side wall of another hollow cylindrical body 31 and the inner side wall of the second tubular body 13. The cooling gap 23 closes at the third tubular body 14 forming the outflow section SE and is internally separated in the cooling circuit by a tubular partition wall 32. The cooling circuit has an outflow pipe and a return pipe through which the cooling fluid flows, and the outflow pipe and the return pipe communicate with each other at their ends facing the proximal end 111, and the outflow pipe and the return pipe terminate respectively at opposite ends at the inlet opening 230 and the outlet opening 231 of the cooling fluid flow.

[0142] The inlet opening 230 and outlet opening 231 of the cooling fluid flow are longitudinally offset from each other and are in fluid communication with the inlet manifold 24 and outlet manifold 25, respectively. The inlet manifold 24 and outlet manifold 25 are each composed of an annular chamber, which are formed sequentially within the first intermediate tubular body 12b and the first connecting tubular body 12c, and are provided with corresponding connecting fittings 240 and 250 for allowing the cooling fluid to enter and exit.

[0143] Figure 7 The embodiment shown—which illustrates a cross-section taken at the transport section ST—is consistent with Figures 1 to 12. Figure 6The implementation differs in that the partition wall 27' has three radial planes that divide the internal volume of the hollow cylindrical body 26 into three sectors. These three sectors have a circular sector shape in cross-section and form three tubular pipes 17', 17" and 17'''. For the rest, refer to Figures 1 to 12. Figure 6 The components described are indicated by the same reference numerals. The partition wall 27' is shaped to form three distinct chambers 17', 17"', and 17'''' inside the cavity of the spray gun 10, each chamber defining a corresponding tubular conduit. The partition wall 27' can be made as a single piece or alternatively as a series of separate components connected together, provided that fluid separation between the three tubular conduits 17', 17"', and 17''' is ensured. In this embodiment, the solid material flow manifold and the corresponding connecting fittings connected to the solid material source are consistent with those shown in Figures 1 to 12. Figure 6 The feed manifolds and fittings described in the illustration are similar. Three feed manifolds will be provided, each with a corresponding fitting connected to a source of a corresponding solid material flow. The three feed manifolds will be arranged to each serve a corresponding tubular conduit 17', 17”, 17'''. Similarly, each tubular conduit 17', 17”, 17''' may be provided with a corresponding fitting for feeding a corresponding auxiliary gaseous flow into the tubular conduit.

[0144] Figure 8 The embodiment shown—which illustrates a cross-section taken at the transport section ST—is consistent with Figures 1 to 12. Figure 6 The implementation differs in that each of the tubular conduits 17', 17”, 17''' is formed by a corresponding longitudinal hole in the solid cylindrical body 28. Even in this case, compared with the already shown in Figure 1 to Figure 6 The corresponding elements described are also indicated by the same reference numerals. In this case, the covering gap 21 is defined by a pair of first tubular walls, which, as described above, are correspondingly formed by the outer side wall of a solid cylindrical body 28 and the inner side wall of another hollow cylindrical body 31.

[0145] Figure 9A The embodiment shown—which depicts a cross-section taken at the transport section ST—is similar to... Figure 8The implementation differs in that each of the tubular conduits 17', 17”, 17''' is constituted by a corresponding hollow cylindrical body 29', 29”, 29''', which is housed within another outer hollow cylindrical body 30. In this case, the covering gap 21 is defined by a pair of first tubular walls, which, similarly as described above, are correspondingly constituted by the outer side wall of the outer cylindrical body 30 and the inner side wall of the other hollow cylindrical body 31.

[0146] Figure 9 The embodiments shown are similar to Figure 9A The implementation method differs in that there is no hollow cylindrical body 30. In this case, the covering gap 21 is defined by the outer surface of the hollow cylindrical bodies 29', 29”, 29''' and the inner wall of another hollow cylindrical body 31, similar to the above.

[0147] In all the alternative embodiments described above, a number of corresponding solid material flow feed manifolds are provided, equal to the number of tubular pipes 17', 17”, and 17'''. Each of the tubular pipes 17', 17”, and 17''' is provided with a corresponding connecting fitting connected to the source of the corresponding solid material flow. The connecting fittings are arranged to serve each corresponding tubular pipe 17', 17”, and 17'''. Similarly, each tubular pipe 17', 17”, and 17''' may be provided with a corresponding connecting fitting for feeding a corresponding auxiliary gaseous flow into the tubular pipe.

[0148] It should be noted that the arrangement of tubular pipes 17', 17" with longitudinal extension axes B', B" parallel to each other and not overlapping and parallel to the central longitudinal axis A allows all corresponding first inlets 172', 172" to be positioned at the same level, i.e., at the same cross-section of the spray gun 10. Consequently, corresponding feed manifolds 18', 18" with corresponding connecting joints 19', 19" can also be arranged at the same level, i.e., at the same cross-section of the spray gun 10, and formed in the same longitudinal section of the housing 11, without needing to offset them from each other, which allows for a reduction in the longitudinal dimension of the spray gun 10.

[0149] The tubular conduits 17', 17" or at least their inner walls can be constructed of different (metallic or ceramic) materials, or treated with a surface coating that reduces the tendency for wear or corrosion by incorporating the physical-chemical properties of the injected solid material; the same inner walls or tubes can be made in longitudinal sections, or even made of different materials from each other. For example, depending on the chemical-physical properties (e.g., abrasiveness) of the solid material passing through the tubular conduit, a surface finish or surface material can be used for each individual tubular conduit 17', 17"

[0150] The injection of solid material streams can be carried out under subsonic, sonic, or supersonic conditions. For solid material streams injected under sonic or supersonic conditions, the corresponding tubular conduits 17', 17” are provided with convergent-diffusion channels (Laval nozzles) near the corresponding outlets 173', 173”.

[0151] Another object of the present invention is a particulate and / or powder solid material injection system 400 for injecting solid materials in particulate and / or powder form into a metallurgical furnace 500. Figure 10 The system 400 includes a spray gun 10 as described above and at least one source S1, S2...Sn, the source being connected to the connection joint for feeding a stream of solid material in the form of particles and / or powder.

[0152] Advantageously, such a system 400 includes, for each of the tubular conduits 17', 17" is a corresponding feed source S1, S2...Sn connected to the corresponding connecting joint for a flow of a corresponding solid material in particulate and / or powder form, wherein the feed sources S1, S2...Sn are different from each other in terms of the solid material in particulate and / or powder form being fed and / or in terms of the fluid being transported.

[0153] Then, as Figures 10 to 12 As shown, system 400 includes at least one feed source G, G1, G2...Gn for assisting the gaseous flow, the feed source G, G1, G2...Gn being connected to connecting fittings 20', 20' connected to second inlets 174', 174' of tubular pipes 17', 17'" for supplying the assisting gaseous flow to accelerate the corresponding solid material flow in the tubular pipes 17', 17'".

[0154] The auxiliary gaseous flow helps align the solid material flow with the axial extension of the corresponding tubular conduits 17', 17" and accelerates the solid material flow toward the corresponding outlets 173', 173" . This allows for reduced wear on the walls of the tubular conduits 17', 17" , particularly at the corresponding first inlets 172', 172" , and even more specifically, in the case where the first inlets 172', 172" extend along directions C', C" intersecting the longitudinal extension axes B', B" of the corresponding tubular conduits 17', 17" .

[0155] As mentioned above, each solid material stream consists of solid material in the form of particles and / or powder, and a carrier fluid or transport fluid, which is typically a carrier gas, such as air, oxygen, or an inert gas, such as nitrogen or argon.

[0156] The solid material flows fed into the different tubular pipes 17', 17” may differ from each other, for example, in the type of solid material and / or in the type of fluid being transported and / or in the characteristics of the feed flow (flow rate, velocity, temperature, pressure, etc.). Regarding the characteristics of the feed flow, system 400 includes valves, pressure regulators, flow regulators, flow meters, pressure gauges, and any other means necessary to perform the desired regulation, which are known in themselves and therefore not described in detail.

[0157] exist Figure 10 In the embodiments illustrated herein, for each tubular conduit 17', 17'', a corresponding source S1, S2 for a solid material flow and a corresponding source G1, G2 for an auxiliary gaseous flow are provided, wherein the sources S1, S2 for the solid material flow deliver both the solid material and the carrier fluid.

[0158] Figure 11 The illustrated embodiment differs from the previous embodiment in that a single source G of auxiliary gas is provided, from which different pipes are led out for connection to connecting fittings 20', 20" of the tubular pipes 17', 17" (each tubular pipe in the tubular pipes 17', 17" corresponds to a connecting pipe). Regulating valves 402', 402" and pressure gauges 403', 403" are arranged along said different pipes. Still in this case, the auxiliary gas flow supplied in each tubular pipe 17', 17" is separated from each other. Then, regulating valves 401', 401 are schematically shown for the flow of solid material supplied to each tubular pipe 17', 17" respectively.

[0159] Figure 12 The implementation shown is different Figure 11 The implementation method involves drawing different pipes from the same auxiliary gas source G. These different pipes are used to connect to the connecting joints 19', 19" of the tubular pipes 17', 17" (each tubular pipe in the tubular pipes 17', 17" corresponds to one connecting pipe). Regulating valves 404', 404" and pressure gauges 405', 405" are arranged along these different pipes. In this case, the same gas is used both as a carrier fluid or conveying fluid for forming a solid material flow and as an auxiliary gaseous fluid for forming an auxiliary gaseous flow. Sources S1 and S2, with corresponding regulating valves 406', 406" in place, deliver the corresponding solid materials to the corresponding connecting pipes.

[0160] Such a system may then include a supersonic process gas (e.g., oxygen) injector 300 connected to the spray gun 10.

[0161] Another object of the present invention is a metallurgical furnace 500, such as EAF, which is provided with a spray gun 10 or injection system 400 as claimed and described.

[0162] like Figures 10 to 12 As shown in the figure, the furnace 500 includes a spray gun 10, which is installed in an opening formed in the wall of the furnace 500, wherein the distal end 110 is disposed outside the furnace 500, and wherein the proximal end 111 is disposed inside the furnace 500 near a metal bath contained in the furnace 500.

[0163] Another object of the present invention is a process for producing steel in an electric arc furnace 500 as described above, wherein at least two streams of solid material that are different from each other are simultaneously or at a delayed time injected into a metal bath contained in the furnace 500 through the same spray gun 10, each stream of solid material being fed separately from the other stream of solid material in a corresponding tubular conduit 17', 17" of the same spray gun 10.

[0164] Advantageously, the corresponding auxiliary gaseous flow is supplied to at least one of the tubular conduits 17', 17" to accelerate the corresponding solid material flow.

[0165] The purpose of the injection gun created by this invention is to reduce the number of openings formed in the furnace wall and the number of cooling supports for supporting and cooling the gun when the solid material to be injected into the furnace is of the same type, thereby resulting in advantages in reducing heat loss to the environment and thus leading to higher overall efficiency of the equipment.

[0166] The spray gun created according to the present invention also allows for a reduction in the overall number of operating devices, as each individual spray gun allows for the management of multiple solid materials, resulting in lower maintenance and management costs.

[0167] Furthermore, the spray gun created according to the invention allows for simplified modernization (upgrading) of existing furnaces for injecting new and / or different solid materials into the furnace. For example, an existing furnace equipped with an injector for coal can also be configured to inject polymer materials that are chemically and physically incompatible with injectors optimized for coal. For this purpose, it is sufficient to replace the operating injector with the spray gun created according to the invention without modifying the furnace structure, and in particular without creating additional openings, thereby reducing the investment cost of the upgrade.

[0168] The spray gun created according to the invention then allows for improved injection efficiency due to the optimized positioning of a single spray gun for injecting solid materials, combined with a supersonic oxygen jet. This allows for the use of such a supersonic flow for multiple solid materials, rather than having multiple spray guns for injecting solid materials near a single oxygen spray gun, which would result in suboptimal positioning. Thus, the penetration of the solid material injected into the slag layer can be optimized while minimizing the risk of it being dragged towards the flue gas extraction device by the fluid flow.

[0169] Then, by utilizing the spray gun created according to the invention, an overall improvement in process efficiency and flexibility can be achieved: multiple optimized solid material flows are provided for each single type of solid material to be injected, and advanced configurations for controlling temperature and optimizing slag “foaming” can be managed using optimized positioning of a possible supersonic oxygen injector. For example, it is possible to switch from injecting low-volatile solid materials (e.g., coal) to injecting high-volatile solid materials (e.g., plastics, rubber, biochar) because materials suitable for controlling potential temperature hotspots, which may be formed due to excessive local fluidization of the slag caused by high volatility, can be injected simultaneously and in the same flow.

[0170] Furthermore, compared to the solution known from US6558614, the spray gun created according to the present invention has greater compactness due to the tubular conduits 17', 17" being placed side by side and parallel to each other rather than concentrically, which allows the feed manifold and corresponding connection joints to be placed side by side to the corresponding feed source, and thus reduces the longitudinal dimension.

[0171] Furthermore, if needed, the optimized and uniform cross-section of the flow path for all solid material flows can be ensured, unlike existing solutions with concentric paths where the path thickness decreases with distance from the nozzle axis in the same section. Finally, separating the nozzle for injecting solid materials from the nozzle for injecting the supersonic gas (oxygen) jet allows for alteration of the distance between the center of the oxygen supersonic jet and the center of the solid material jet, as well as the inclination between the directions of the oxygen supersonic jet and the solid material jet, resulting in greater injection flexibility and better injection distribution in the bath.

[0172] The injection gun conceived in this way is easily modified and varied, all of which fall within the scope of this invention; furthermore, all details can be replaced by technically equivalent components. In practice, the materials used and the dimensions can be arbitrary, depending on the technical requirements.

Claims

1. A particulate and / or powder solid material injection gun (10) for injecting solid materials in the form of granules and / or powders into a metallurgical furnace, characterized in that, The particulate and / or powder solid material injection gun (10) includes: - A tubular housing (11) having a central longitudinal axis (A) and extending between a distal end (110) and a proximal end (111) that are axially opposite to each other, and along the tubular housing (11) starting from the distal end (110), the following longitudinal sections are connected to each other: a feeding section (SA) of solid material in the form of granules and / or powder, a conveying section (ST) of the fed solid material and an outflow section (SE) of the conveyed solid material, the outflow section (SE) including an outflow opening (15) located at the proximal end (111). - A plurality of different tubular conduits (17', 17") are arranged inside the housing (11), wherein each of the tubular conduits (17', 17") has a longitudinally extending axis (B', B") and extends longitudinally between a first end (170', 170") and a second end (171', 171") along at least a portion of the feed section (SA) and along at least a portion of the transport section (ST), in the feed section (SA) At the location, the tubular conduit (17', 17") has at least one first inlet (172', 172") of a corresponding solid material flow (FS', FS") in the form of particles and / or powder, the conveying section (ST) terminating at an outlet (173', 173") of a corresponding solid material flow in fluid communication with the outlet opening (15), wherein the longitudinal extension axes (B', B") of the tubular conduit (17', 17") do not overlap with each other and are parallel to the central longitudinal axis (A); and - At least one feed manifold (18', 18"), the at least one feed manifold (18', 18") being used for each of the tubular pipes (17', 17"), wherein the at least one feed manifold (18', 18") is associated with the housing (11) at the feed section (SA) and is in fluid communication with the at least one first inlet (172', 172") of the corresponding tubular pipe (17', 17"), and is provided with at least one connection joint (19', 19") capable of being connected to the feed source (S1, S2) of the corresponding solid material flow.

2. The injection gun (10) for granular and / or powdered solid materials according to claim 1, wherein, The first inlet (172', 172") is formed at the sidewall that demarcates the corresponding tubular conduit (17', 17"), and extends along a direction (C', C") that intersects the longitudinal extension axis (B', B") of the corresponding tubular conduit (17', 17") and thus forms a non-zero angle (α) with the longitudinal extension axis (B', B"), or wherein, The first inlet (172', 172") is formed at the first end (170', 170") of the corresponding tubular conduit (17', 17") and extends in a direction parallel to or coincident with the longitudinal extension axis (B', B") of the corresponding tubular conduit (17', 17").

3. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, At least one of the tubular conduits (17', 17") includes at least one second inlet (174', 174") of an auxiliary gaseous flow (FG', FG"), wherein the second inlet (174', 174") is defined along a longitudinal portion of the tubular conduit (17', 17") extending along the feed section (SA), and the second inlet (174', 174") is in fluid communication with a corresponding connecting fitting (20', 20"), which is connectable to a feed source (G1, G2) of the auxiliary gaseous flow.

4. The injection gun (10) for granular and / or powdered solid materials according to claim 3, wherein, The second inlet (174', 174") is formed at the first end (170', 170") of the tubular conduit (17', 17"), and extends along a direction (D', D") parallel to or coinciding with the longitudinal extension axis (B', B") of the corresponding tubular conduit (17', 17"), or wherein, The second inlet (174', 174") is formed at the sidewall that demarcates the corresponding tubular conduit (17', 17"), and extends along a direction that intersects the longitudinal extension axis (B', B") of the corresponding tubular conduit (17', 17") and thus forms a non-zero angle with the longitudinal extension axis (B', B").

5. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, There is a distance H between the outlet (173', 173") of each tubular conduit in the tubular conduit (17', 17") and the outflow opening (15), the distance H being between 0% and 90% of the total length of at least the conveying section (ST) and the outflow section.

6. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, include: - At least one encapsulation gap adapted to be traversed by an encapsulated gaseous flow (21), the encapsulation gap extending longitudinally along at least a portion of the feed section (SA) and at least a portion of the transport section (ST), wherein the encapsulation gap has at least one inlet opening (210) for the encapsulated gaseous flow at the feed section (SA), the encapsulation gap terminating at an outlet opening (211) of the encapsulated gaseous flow in fluid communication with the outlet opening (15), wherein the encapsulation gap (21) externally surrounds the tubular conduit (17', 17"), and - At least one feed manifold (22) is associated with the housing (11) at the feed section (SA) and is in fluid communication with the at least one inlet opening (210) of the cover gap (21), and is provided with at least one corresponding connection fitting (220) capable of being connected to the feed source (GC) of the corresponding cover gas flow.

7. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, include: - At least one cooling gap (23) forming or accommodating a cooling circuit and extending longitudinally along at least a portion of the feed section (SA) and at least a portion of the transport section (ST), wherein the cooling circuit has at least one inlet opening (230) and at least one outlet opening (231) for the flow of cooling fluid in the feed section (SA), wherein the cooling gap (23) externally surrounds the components of the tubular conduit (17', 17"), and - At least one input manifold (24) and at least one output manifold (25), the at least one input manifold (24) and the at least one output manifold (25) being associated with the housing (11) at the feed section (SA) and in fluid communication with at least one input opening (230) and at least one output opening (231) of the cooling circuit, respectively, and each of the at least one input manifold (24) and the at least one output manifold (25) being provided with at least one corresponding fitting (240, 250) capable of being connected to the feed source of the cooling fluid flow and the discharge port of the cooling fluid flow, respectively.

8. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, Each of the tubular conduits (17', 17") consists of a corresponding sector of a hollow cylindrical body (26) arranged inside the housing (11) and coaxial with the central longitudinal axis (A), each sector being demarcated by a portion of the sidewall of the hollow cylindrical body (26) and at least one longitudinal partition wall (27, 27') extending inside the hollow cylindrical body (26).

9. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, Each of the tubular conduits (17', 17") is composed of a corresponding hollow cylindrical body (29', 29").

10. The injection gun (10) for granular and / or powdered solid materials according to claim 1 or 2, characterized in that, Each of the tubular conduits (17', 17") consists of a corresponding longitudinal hole formed in a solid cylindrical body (28).

11. A particulate and / or powder solid material injection system (400) for injecting solid materials in particulate and / or powder form into a metallurgical furnace, characterized in that, The particulate and / or powder solid material injection system (400) includes a particulate and / or powder solid material injection gun (10) according to any one of the preceding claims 1 to 10 and at least one feed source for a flow of solid material in particulate and / or powder form connected to the connecting joint.

12. The particulate and / or powder solid material injection system (400) according to claim 11, characterized in that, For each of the tubular conduits (17', 17"), the granular and / or powdered solid material injection system (400) includes a corresponding feed source (S1, S2) connected to the corresponding connecting joint for a corresponding solid material flow in granular and / or powdered form, wherein each solid material flow includes solid material in granular and / or powdered form and a conveying fluid, and wherein the feed sources (S1, S2) differ from each other in terms of the solid material in granular and / or powdered form fed and / or in terms of the conveying fluid.

13. The particulate and / or powder solid material injection system (400) according to claim 12, characterized in that, Includes a supersonic process gas injector (300) connected to the injection gun (10) for the particle and / or powder solid material.

14. The particulate and / or powder solid material injection system (400) according to any one of claims 11 to 13, characterized in that, Includes at least one feed source (G1, G2) for an auxiliary gaseous flow, the feed source (G1, G2) being connected to the connecting fitting (20', 20") connected to the second inlet (174', 174") of the tubular conduit (17', 17") for supplying the auxiliary gaseous flow to accelerate the corresponding solid material flow in the tubular conduit (17', 17").

15. An electric arc furnace (500) for performing a method of producing steel, characterized in that, The electric arc furnace (500) includes at least one particulate and / or powder solid material injection gun (10) according to any one of claims 1 to 10, the distal end (110) of the particulate and / or powder solid material injection gun (10) being disposed outside the electric arc furnace (500), and the proximal end (111) of the particulate and / or powder solid material injection gun (10) being disposed inside the electric arc furnace (500) near a metal bath contained in the electric arc furnace (500).

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