Burner

Abstract

The present application relates to a burner (1) for a shaft melting furnace, in particular for a copper shaft melting furnace, comprising a first chamber (4) with an inlet opening (14), via which an oxygen-containing gas can be supplied to the burner (1), and an outlet opening (16), which is arranged at a distal end of a conically tapering sub-portion (5) of the first chamber (4); a second chamber (6), which is connected to the conical sub-portion (5) of the first chamber (4) and which has a burner nozzle (7); a combustion gas line (21), which opens into the first chamber (4) and via which a combustion gas can be supplied to the burner (1); and a mixing nozzle (19), which is arranged in the outlet opening (16) of the first chamber (4) and which has a mixing chamber (20) via which the oxygen-containing gas and the combustion gas can be mixed to form a combustion gas mixture.

Description

[0001] The present invention relates to a burner for a shaft melting furnace, in particular for a copper shaft melting furnace, and to a shaft melting furnace, in particular a copper shaft melting furnace, comprising the at least one burner according to the invention.

[0002] Whether in electrical engineering and electronics, heating and air conditioning, or the automotive industry, the use of copper and copper alloys has become an indispensable part of modern life, driving steadily rising global demand for this precious metal. However, this global demand is offset by increased safety and environmental requirements for production. High-performance burners, among other things, are essential for this.

[0003] Burners for a shaft melting furnace are generally known from the prior art. For example, WO 90 / 02909 discloses a generic burner with a conical first chamber, an adjoining mixing chamber, and a telescopic eyepiece extending axially through the burner. The burner known from WO 90 / 02909 exhibits essentially complete combustion and a uniform flame composition, but does not meet today's more stringent environmental requirements and does not allow for permanent flame monitoring. DE 2062144 A1 also describes a burner for a shaft melting furnace for melting copper.

[0004] The present invention is therefore based on the object of further developing a burner known from the prior art in such a way that it is improved in terms of its energy balance. The object of the present invention is preferably to provide a burner that enables homogeneous mixing between an oxygen-containing gas and a fuel gas while simultaneously reducing pressure loss. Description of the invention

[0005] According to the invention, the object is achieved by a burner having the features of patent claim 1.

[0006] The burner according to the invention is provided for a shaft melting furnace, in particular for a copper shaft melting furnace, and comprises a first chamber with an inlet opening through which an oxygen-containing gas, such as air, oxygen-enriched air, or pure oxygen, can be supplied to the burner, and an outlet opening arranged at a distal end of a conically tapered section of the first chamber; and a second chamber connected to the conical section of the first chamber with a burner nozzle.

[0007] According to the invention, the burner comprises a fuel gas line opening into the first chamber, via which a fuel gas can be supplied to the burner; and a mixing nozzle arranged in the outlet opening of the first chamber with a mixing chamber, via which the oxygen-containing gas and the fuel gas can be mixed to form a fuel gas mixture.

[0008] Hydrocarbon-containing gases, especially methane or natural gas, hydrogen, or mixtures thereof, are particularly suitable as fuel gases. The mixture, for example one of natural gas or methane and hydrogen, is advantageously premixed individually in the range of 1 to 100 vol.%, for example in a valve station, and then fed to the burner via the fuel gas line. One advantage of adding hydrogen to the hydrocarbon-containing gas is that it allows for flexible responses to future increases in CO2 prices. It is particularly preferred that the hydrogen be produced using renewable energies.

[0009] By arranging the fuel gas line within the first chamber, which serves as a collection chamber for the oxygen-containing gas, the fuel gas is premixed with the oxygen-containing gas. The premixed fuel gas mixture then flows through the mixing nozzle located in the outlet opening and is then homogeneously mixed in the mixing chamber, which advantageously has a specific mixing geometry. The entire mixing nozzle is designed in such a way that it causes a particularly low pressure loss of only 70 mbar. This ultimately ensures that the permanent pressure loss at the burner can be continuously kept to a minimum, giving the burner a better energy balance than prior art burners.

[0010] Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, where further preferred embodiments of the invention are presented.

[0011] In order to further increase the first intersection between the oxygen-containing gas and the fuel gas within the first chamber, it is advantageously provided that the fuel gas line opens into the conically tapered section of the first chamber and particularly preferably comprises at least one or a plurality of nozzle openings by means of which the fuel gas can be supplied at an angle of 30° to 60° relative to a longitudinal axis of the burner to the oxygen-containing gas, which is essentially rectified as it flows through the conical section as it flows through the first chamber.

[0012] As already explained, the mixing nozzle causes a particularly low pressure loss, which has a beneficial energetic effect on the operation of the burner. The low pressure loss is achieved through the specific mixing geometry, which is advantageously formed by a plurality of blades arranged in the mixing chamber. The mixing chamber is annular and has an inner ring and an outer ring. Within the annular mixing chamber, the mixing nozzle preferably has a first set of blades arranged radially on the outside and a second set of blades arranged radially on the inside, wherein the two sets of blades are arranged in opposite directions to one another, preferably in such a way that each blade of the first set forms three shear planes with three blades of the second set, or each blade of the second set forms three shear planes with three blades of the first set.This arrangement ensures that the fuel gas mixture flowing over the blade surfaces of the radially outer blades impacts the blade surfaces of the radially inner blades, which are arranged essentially perpendicularly to these surfaces, and mixes with the fuel gas mixture flowing over the blade surfaces of the radially inner blades, and vice versa. This multiple blending of the already premixed fuel gas mixture achieves a homogeneous mixing of the two gases while simultaneously maintaining a low permanent pressure loss.

[0013] In an advantageous embodiment, the burner further comprises an observation device with a viewing axis extending through the first chamber, the mixing nozzle, the second chamber and the burner nozzle, via which the outlet area of ​​the burner as well as the flame chamber of the shaft melting furnace can be monitored by an operator or by means of a camera module in order to be able to react to disturbances in the flame chamber.

[0014] For this purpose, the observation device advantageously comprises a tube which extends axially through the first chamber, wherein a first end of the tube is arranged outside the burner and comprises a sight glass and / or a camera module, and a second end of the tube is arranged in a central opening of the mixing nozzle and is locked, for example, by means of a bayonet lock. From a flow dynamics perspective, it has been shown that a fuel gas line arranged coaxially around the tube of the observation device is particularly advantageous. Therefore, in this context, it is preferred that the fuel gas line is arranged coaxially around the tube of the observation device and, at its end oriented towards the mixing nozzle, comprises a plurality of nozzle openings which are particularly preferably distributed over the circumference thereof.Each of the plurality of nozzle openings is aligned at an angle of 40° to 50°, preferably at an angle of 45°, relative to the visual or longitudinal axis of the burner in order to achieve a particularly high first blend between the fuel gas flowing out of the nozzle openings and the oxygen-containing gas.

[0015] At the end of the second chamber axially opposite the mixing nozzle is the burner nozzle, which advantageously comprises a plurality of guide vanes. These are arranged in a front region of the burner nozzle in the direction of flow. The guide vanes are designed and aligned in such a way that the fuel gas mixture is driven towards the center of the channel, thereby deliberately creating turbulence in the central region and thus preventing free flow of the fuel gas mixture. This ensures, while simultaneously maintaining the line of sight, that a homogeneous velocity profile is realized across the entire jet pipe cross-section and that the fuel gas mixture has fully reacted before impacting the molten material to be melted, thus preventing unreactive strands.

[0016] In the rear region in the direction of flow, the burner nozzle then has a conically tapered outlet opening, the edge of which, according to an advantageous embodiment, has a serrated structure, in particular one provided with recesses, through which turbulence can be specifically generated, leading to the formation of a stable flame root. The burner is ignited in this case by means of an ignition ionization candle located just behind the edge and is advantageously continuously monitored via an ionization monitoring system. This requires that the monitoring wire is always positioned in the flame throughout the entire performance range of the burner. This can be ensured at all times by the formation of the stable flame root.

[0017] In a further aspect, the present invention also relates to a shaft melting furnace, in particular a copper shaft melting furnace, comprising at least one, more preferably a plurality of, the burners according to the invention. In this context, it is preferably provided that the at least one, preferably all, of the burners according to the invention is / are arranged at an inclined angle relative to a horizontal line in a wall of the shaft melting furnace. Character description

[0018] The invention and the technical environment are explained in more detail below with reference to the figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description and / or figures. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. The same reference numerals denote the same objects, so that explanations from other figures can be used as a supplement if necessary. They show: Fig. 1 a variant of the burner according to the invention in a perspective view, Fig. 2 which in Figure 1shown embodiment of the burner according to the invention in a sectional view, Fig. 3 a variant of the pipe with the fuel gas line in a perspective view, Fig. 4 a variant of the mixing nozzle in a perspective view, Fig. 5 which in Figure 4 shown design variant of the mixing nozzle in a sectional view, Fig. 6 a variant of the burner nozzle in a perspective view, Fig. 7 which in Figure 6 shown variant of the burner nozzle in a sectional view, and Fig. 8 which in the Figure 6 and 7 shown design variant of the burner nozzle in a front view.

[0019] In Figure 1A perspective view of a variant of the burner 1 according to the invention is shown. This burner can generally be used in all metallurgical melting units where visual combustion chamber monitoring is required. However, it is preferably provided that the burner 1 is used in a copper shaft melting furnace (not shown) in which copper cathodes are melted to recover copper.

[0020] The burner 1 shown in the present embodiment comprises a first nozzle 2, via which an oxygen-containing gas, such as air, can be supplied to the burner 1, and a second nozzle 3, via which a fuel gas can be supplied to the burner 1. The fuel gas can, for example, comprise a hydrocarbon-containing gas, such as natural gas or methane, hydrogen, or a mixture thereof. Furthermore, the burner 1 comprises a first chamber 4, which has a conical section 5, a second chamber 6 with a burner nozzle 7 (see Fig. 2 ), as well as a jet pipe 8. The jet pipe 8 is made of silicon carbide. In the rear part, the burner 1 also has an observation device 9 and a camera module 10, via which visual combustion chamber monitoring can be carried out. As can be seen from the illustration in Figure 1As can be seen, the burner 1 further comprises a first measuring nozzle 11, which is arranged in the first nozzle 2, and a second measuring nozzle 12, which is arranged at a distal end of the second chamber 6. Via the two measuring nozzles 11, 12, for example, the volume flows and / or the composition of the oxygen-containing gas or the fuel gas mixture can be detected. Furthermore, an ignition ionization candle 13 is arranged at the distal end of the second chamber 6, via which the fuel gas mixture in the burner nozzle 7 can be ignited and the flame can be monitored immediately thereafter. Figure 1 Burner 1 shown is designed for a throughput of 900 Nm3 / h and has a pressure loss of only 90 mbar.

[0021] In order to be able to install the burner 1 ergonomically, it has two crane eyes 41 on the outside of the second chamber 6, which are located at the center of gravity and each include an elongated hole in order to compensate for changes in the center of gravity that may arise from additional attachments.

[0022] Burner 1 can be operated from above, as shown in Figure 2 and 3 The burner 1 can be fed with the oxygen-containing gas both from the top and from below, as shown. If feeding the oxygen-containing gas from below is advantageous, the burner 1 is rotated by 180°. The second nozzle 3, through which the fuel gas is fed to the burner 1, can also be mounted rotated by 90° increments depending on the installation conditions, whereby the axial design does not affect the effect of the burner 1.

[0023] Figure 2 shows the Figure 1illustrated embodiment of the burner 1 according to the invention in a sectional view, but without the camera module 10.

[0024] This illustration shows, on the one hand, the first chamber 4, which has an inlet opening 14, through which the oxygen-containing gas is introduced into the first chamber 4 via the first nozzle 2. The first chamber 4 comprises, in addition to a main section 15, into which the inlet opening 14 opens, the conically tapered section 5, which has an outlet opening 16 arranged at its distal end. Connected to the conical section 5 of the first chamber 4 is the second chamber 6, which is formed from a hollow cylindrical element, for example a tube, and has a first end 17 facing the conical section 5, as well as an axially opposite second end 18, at which the burner nozzle 7 is arranged. The burner nozzle 7 is manufactured from steel using an additive manufacturing process and is produced in the Figures 6 to 8 explained in more detail.

[0025] At the first end 17 of the second chamber 6 or in the outlet opening 16 of the first chamber 4, a mixing nozzle 19 with a mixing chamber 20 is arranged, via which the oxygen-containing gas and the fuel gas can be mixed to form a fuel gas mixture. The fuel gas is introduced into the burner 1 via a fuel gas line 21, which opens into the first chamber 4, in particular into the conically tapered section 5 of the first chamber 4.

[0026] As can be seen from the illustration in Figure 2 As can be seen, the fuel gas line 21 in the embodiment shown here is arranged coaxially around a pipe 22 of the observation device 9 and has, at its end oriented towards the mixing nozzle 19, a plurality of nozzle openings 23 which are arranged distributed over the circumference thereof (see Figure 3). Each of the nozzle openings 23 is aligned at an angle of 40° to 50° relative to a viewing axis 28 of the burner 1 in order to achieve a first blend between the fuel gas flowing out of the nozzle openings 23 and the oxygen-containing gas flowing through the first chamber 4. The fuel gas mixture thus premixed in front of the mixing nozzle 19 then flows through the mixing nozzle 19. The tube 22 of the observation device 9, which extends axially through the first chamber 4, has a first end 24. This is arranged outside the burner 1 and comprises a sight glass 25 or alternatively the camera module 10 ( Figure 1), through which visual monitoring of the combustion chamber can be carried out. Through the sight glass 25, an operator can look into the interior of a shaft melting furnace along the viewing axis 28 extending through the first chamber 4, the mixing nozzle 19, the second chamber 6, and the burner nozzle 7 in order to identify malfunctions. Furthermore, the tube 22 comprises a second end 26, which is arranged in a central opening 27 of the mixing nozzle 19 and is fixedly connected to it via a bayonet lock 29 (see Figure 3 ).

[0027] In the Figure 4 and 5The mixing nozzle 19 is shown with its specific mixing geometry, which, like the burner nozzle 7, was manufactured using an additive manufacturing process, but in contrast to the latter, is made of silicon carbide. In the embodiment variant shown here, the mixing nozzle 19 has an annular mixing chamber 20, which is delimited by an inner ring 30 and a radially opposite outer ring 31. Blades 32, 34 are arranged within the mixing chamber 19, via which blades the premixed fuel gas mixture can be homogeneously mixed by multiple intersections in the flow direction. In detail, the mixing chamber 20 comprises a first set of blades 32 arranged radially on the outside, which are carried by the outer ring 31, and a second set of blades 34 arranged radially on the inside, which are arranged opposite to the first set and are carried by the inner ring 30.The blades 32, 34 of the two sets are arranged relative to one another in the circumferential direction such that each blade 32 of the first set forms three shear planes with three blades 34 of the second set, or each blade 34 of the second set forms three shear planes with three blades 32 of the first set. In other words, the fuel gas mixture flowing over the blade surfaces 33 of the radially outer blades 32 is directed onto the blade surfaces 35 of the radially inner blades 34, which are arranged essentially perpendicular thereto, where it mixes with the fuel gas mixture flowing over the blade surfaces 35 of the radially inner blades 34, and vice versa. In addition, each of the plurality of blades 32, 34 has a slightly curved shape in cross-section.

[0028] In the Figures 6 to 8A variant of the burner nozzle 7 is shown in different representations. This essentially consists of a hollow cylindrical element and has a plurality of guide vanes 36 in a front area, via which the fuel gas mixture can initially be guided through a central channel 37 formed between the guide vanes 36 ( Figure 8 ). As can be seen from the illustration in Figure 7 As can be seen, the individual guide vanes 36 have an arcuate bend, whereby the fuel gas mixture is first driven into the center when flowing through the front area of ​​the burner nozzle 7 before it passes through the channel 37. This is essentially defined by the distal end sections of the individual guide vanes 36 ( Figure 8 ). Immediately behind it in the direction of flow, the burner nozzle 7 has a conically tapered outlet opening 38, the surrounding end face or edge 39 of which has a structure provided with recesses 40. List of reference symbols

[0029] 1 Burner 2 First nozzle 3 Second nozzle 4 First chamber 5 Conical section 6 Second chamber 7 Burner nozzle 8 Jet pipe 9 Observation device 10 Camera module 11 First measuring nozzle 12 Second measuring nozzle 13 Ignition ionization candle 14 Inlet opening 15 Main section 16 Outlet opening 17 First end of the second chamber 18 Second end of the second chamber 19 Mixing nozzle 20 Mixing chamber 21 Fuel gas line 22 Pipe 23 Nozzle openings 24 First end of the pipe 25 Sight glass 26 Second end of the pipe 27 Central opening 28 Sight axis 29 Bayonet fitting 30 Inner ring 31 Outer ring 32 First set of blades 33 Blade surface of radially outer blades 34 Second set of blades 35 Blade surface of radially inner blades 36 Guide vanes 37 Channel 38 Tapered outlet opening Burner nozzle 39 End face / edge 40 Recesses

Claims

1. Burner (1) for a shaft smelting furnace, particularly for a copper shaft smelting furnace, comprising a first chamber (4) with an inlet opening (14) by way of which a gas containing oxygen can be fed to the burner (1) and an outlet opening (16) which is arranged at a distal end of a conically tapering sub-section (5) of the first chamber (4); a second chamber (6), which is connected with the conical sub-section (5) of the first chamber (4), with a burner nozzle (7); characterised by a combustion gas duct (21), which opens into the first chamber (4) and by way of which a combustion gas can be fed to the burner (1); and a mixer nozzle (19), which is arranged in the outlet opening (16) of the first chamber (4), with a mixing chamber (20) by way of which the gas containing oxygen and the combustion gas are miscible to form a combustion gas mixture.

2. Burner (1) according to claim 1, wherein the combustion gas line (21) opens into the conically narrowing sub-section (5) of the first chamber (4).

3. Burner (1) according to claim 1 or 2, wherein the mixer nozzle (19) comprises a plurality of blades (32, 34) arranged in the mixing chamber (20), wherein the mixing chamber (20) is preferably of annular form.

4. Burner (1) according to claim 3, wherein the mixer nozzle (19) has within the annular mixing chamber (20) a first set of radially outwardly arranged blades (32) and a second set of radially inwardly arranged blades (34), wherein the blades (32, 34) of the two sets are arranged in opposite sense to one another.

5. Burner (1) according to any one of the preceding claims, further comprising an observation device (9) with a viewing axis (28) which extends through the first chamber (4), the mixer nozzle (19), the second chamber (6) and the burner nozzle (7) and by way of which a flame space of the shaft smelting furnace can be monitored.

6. Burner (1) according to claim 5, wherein the observation device (9) comprises a tube (22) extending axially through the first chamber (4), wherein a first end (24) of the tube (22) is arranged outside the burner (1) and comprises a viewing pane (25) and / or a camera module (10), and a second end (26) of the tube (22) is arranged in a central opening (27) of the mixer nozzle (19).

7. Burner (1) according to claim 6, wherein the combustion gas duct (21) is arranged coaxially around the tube (22) of the observation device (9) and has at its end oriented towards the mixer nozzle (19) a plurality of nozzle openings (23) which are preferably arranged to be distributed over the circumference thereof.

8. Burner (1) according to any one of the preceding claims, wherein the burner nozzle (7) comprises a plurality of guide blades (36) which are preferably arranged in a forward region of the burner nozzle (7).

9. Burner (1) according to any one of the preceding claims, wherein the burner nozzle (7) has a conically narrowing outlet opening (38) which is preferably arranged in a rearward region of the burner nozzle (7).

10. Burner (1) according to claim 9, wherein the conically narrowing outlet opening (38) has an edge (39) with a serrated structure, particularly a structure provided with recesses (40).

11. Burner (1) according to any one of the preceding claims, wherein the mixer nozzle (19) and / or the burner nozzle (7) consists or consist of silicon carbide.

12. Burner (1) according to any one of the preceding claims, comprising at least one measuring stub pipe (11, 12), preferably at least two measuring stub pipes (11, 12).

13. Burner (1) according to any one of the preceding claims, comprising a nozzle pipe (8) which consists of a ceramic, preferably of silicon carbide (SiC), and which with particular preference is configured to be exchangeable.

14. Shaft smelting furnace, particularly a copper shaft smelting furnace, comprising at least one burner (1) according to any one of the preceding claims.

15. Shaft smelting furnace according to claim 14, wherein the at least one burner (1) is arranged at an inclined angle referred to a horizontal in a wall of the shaft smelting furnace.

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