Apparatus for thermally treating a substance

Abstract

The invention relates to an apparatus (1) for thermally treating a substance, comprising a treatment chamber (2), at least one device (5) for providing a plasma, and a hot-gas channel (6), wherein the hot-gas channel (6) is arranged or formed between the device (5) for providing a plasma and the treatment chamber (2) and has an inlet (7) for a hot-gas flow generated by the device (5) for providing a plasma, and an outlet (8) into the treatment chamber (2). The hot-gas channel (6) has at least one further outlet (8) for the hot-gas flow into the treatment chamber (2). The hot-gas channel (6) and / or the device (5) for providing a plasma may have at least one further inlet (7) for a further hot-gas flow.

Description

[0001] FACILITY FOR THERMAL TREATMENT OF A MATERIAL

[0002] The invention relates to a device for the thermal treatment of a substance, in particular a solid, comprising a treatment chamber, a device for providing a plasma, and a hot gas channel, wherein the hot gas channel is arranged between the device for providing a plasma and the treatment chamber, and has an inlet for a hot gas flow generated by the device for providing a plasma and an outlet for the hot gas flow into the treatment chamber.

[0003] Furthermore, the invention relates to a method for the thermal treatment of a substance, in particular a solid, in a treatment chamber with a hot gas stream which is generated in or with a device for providing a plasma and is introduced into the treatment chamber via a hot gas channel.

[0004] The use of so-called plasma torches of various designs for the thermal treatment of substances, especially metals, is already documented in the state of the art.

[0005] For example, DE10 2020202 484 A1 describes a device for melting metals whose melting temperature is less than 1000 °C, in which a device for forming a plasma is arranged on a melting furnace, wherein the device is connected to an electrical voltage supply and to the device at least one first supply for a plasma gas with which the plasma can be formed, and the device is designed, dimensioned, arranged and / or aligned such that the formed plasma is arranged at a distance from the metal as melting material, and in this case a hot gas flow can be formed with the plasma, which is aligned in the direction of the melting material and a melting tank or crucible is arranged in the melting furnace to receive the molten metal.

[0006] US 2004 / 107796 A1 describes a plasma-assisted melting process comprising: forming a plasma in a cavity by exposing a first gas to electromagnetic radiation having a frequency of less than about 333 GHz in the presence of a plasma catalyst; heating a second gas with the plasma; adding a solid to a melting vessel; and directing the heated second gas toward the solid sufficiently to at least melt the solid. Induction plasma torches are known from EP 1 433 366 A1, DE 69216970 T2, EP 3 314 989 B1, and EP 2 671 430 B1.

[0007] The object of the present invention is to carry out a thermal treatment of a substance using a device for providing a plasma, without melting it, and with the most defined, in particular uniform, temperature distribution possible in the treatment chamber.

[0008] The object is achieved with the device mentioned at the outset in that the hot gas channel has at least one further outlet for the hot gas flow into the treatment chamber and / or that the hot gas channel and / or the device for providing a plasma has / have at least one further inlet for a further hot gas flow.

[0009] Furthermore, the object of the invention is achieved by the method mentioned at the outset, according to which the hot gas stream is introduced into the treatment chamber via several outlets.

[0010] The advantage here is that the at least one additional outlet allows the hot gas flow to be distributed across multiple sections of the treatment chamber. This makes it possible to operate the plasma generation device at a lower frequency, although this results in higher power. Using a lower frequency, in turn, has the advantage that the power electronics used in the plasma generation device are cheaper and more efficient, which in turn can improve the efficiency of the device for thermally treating a material.In addition, by dividing the power of the plasma generation device across multiple sections of the treatment chamber with only one plasma generation device or with a smaller number of plasma generation devices per treatment chamber, the installation and maintenance effort of the device for thermally treating a substance can be reduced.

[0011] According to one embodiment of the invention, it can be provided that the hot gas channel and / or the device for providing a plasma has / have at least one further inlet for a further hot gas stream. The corresponding embodiment of the method provides for the hot gas stream to be mixed with a further hot gas stream before being introduced into the treatment chamber. This makes it possible to further reduce the temperature level of the partial flows of hot gas distributed to the individual outlets of the hot gas channel if the further hot gas stream has a temperature which is lower than that of the hot gas stream from the device for providing a plasma. By regulating the volume flows of hot gas and further hot gas, the temperature of the introduced hot gas can subsequently be adjusted, for example by supplying a correspondingly higher volume flow of “cooler” further hot gas.At the same time, excessive cooling of the hot gas stream from the plasma generation device, as would be the case, for example, if a cold gas stream were introduced, can be avoided. By mixing the additional hot gas stream into the hot gas stream from the plasma generation device, its high thermal output can be more easily distributed among several smaller thermal gas streams.

[0012] According to a further embodiment of the invention, the additional inlet for the additional hot gas stream can be fluidly connected to a further hot gas duct, wherein the additional hot gas duct is fluidly connected to an outlet from the treatment chamber. Thus, with this embodiment, a recirculating flow can be generated, allowing the waste heat from the device for the thermal treatment of a substance to be reused in the device. This can improve the energy balance of the device for the thermal treatment of a substance.

[0013] For a more homogeneous heat distribution in the treatment chamber or for a better mixing of the hot gas streams by creating a larger mixing chamber, according to an embodiment variant of the invention it can be provided that the hot gas channel is designed with a cross-sectional widening.

[0014] To further improve these effects, one embodiment may provide for the cross-sectional expansion to be fan-shaped.

[0015] According to another embodiment of the invention, the outlet and the at least one further outlet can have different cross-sections. This makes it possible to account for or influence pressure losses in the hot gas duct, so that at least approximately equal volumetric partial flows of hot gas enter the treatment chamber through the outlets. This, in turn, enables a more homogeneous temperature distribution in the treatment chamber (relative to the introduced hot gas). Better mixing or better conduction of partial volumes to the outlets can be achieved if, according to one embodiment of the invention, at least one flow guide element is arranged in the hot gas duct.

[0016] According to one embodiment of the invention, it can also be provided that at least one additional flow guide element is arranged in the treatment chamber, covering the outlet and / or the at least one additional outlet. Thus, the substance present in the treatment chamber is not directly exposed to the partial hot gas streams, thus achieving better mixing of the incoming hot gas with the atmosphere in the treatment chamber and thus a more homogeneous temperature distribution.

[0017] According to another embodiment of the invention, the hot gas channel can be formed in a refractory lining of the treatment chamber. This allows for a more homogeneous temperature distribution during continuous operation, since the walls of the treatment chamber can be maintained at a higher temperature over a larger volume.

[0018] According to a further embodiment of the invention, however, it can also be provided that the hot gas channel is arranged partially on an outer side of the treatment chamber, whereby the structural complexity of the device for the thermal treatment of a substance can be reduced.

[0019] According to one embodiment of the invention, at least one additional plasma generating device can be connected to the hot gas channel. This makes it possible, at high total power levels, to nest the outlets associated with one plasma generating device with the other plasma generating device in order to minimize the partial load range. The two plasma generating devices can be alternately switched on and off. This allows a power reduction to be achieved without reducing the power of the plasma generating device.

[0020] According to another embodiment of the invention, it can be provided that the hot gas channel has at least one second inlet for a second hot gas stream, and that an adjusting element for interrupting the supply of the additional hot gas into the hot gas channel or into the device for generating a plasma is arranged in each of the additional and second hot gas streams. This makes it possible to temporarily interrupt the supply of the two additional hot gas streams, so that the hot gas stream formed by the device for providing a plasma can be directed in one direction depending on the supply of one of the two additional hot gas streams. This also makes it possible to divide the hot gas stream between several sections of the treatment chamber.

[0021] According to a further embodiment of the invention, it can also be provided that the device for generating a plasma at an angle of not equal to 90 0 to the wall of the treatment chamber. With this design variant, the hot gas flow can be designed to run at an angle relative to the treatment chamber, thus allowing the size of the mixing zone for mixing with the further hot gas flow to be varied.

[0022] According to one embodiment of the invention, the outlet of the hot gas stream into the treatment chamber can be slit-shaped in order to reach a wider section of the treatment chamber. This also reduces heat losses.

[0023] In order to reduce heat losses, according to an embodiment variant of the invention, it can also be provided that a wall of the treatment chamber, which has the outlet for the hot gas flow, has a material with a lower thermal conductivity on an outer side than a material on an inner side.

[0024] To further influence the temperature of the hot gas exiting the treatment chamber, one embodiment of the invention can provide for at least one heat exchanger to be arranged in the inlet for the additional hot gas flow to the hot gas channel and / or the device. The heat exchanger can also be used to reuse the heat extracted from the additional hot gas flow for another process.

[0025] In order to improve the flow conditions for the hot gas in the hot gas duct, according to one embodiment variant, the hot gas duct can be lined at least in sections with a refractory material.

[0026] For a better understanding of the invention, it is explained in more detail using the following figures.

[0027] They each show in a simplified, schematic representation: Fig. 1 a design variant of a device for the thermal treatment of a material in plan view;

[0028] Fig. 2 shows a section of a variant of a device for the thermal treatment of a material;

[0029] Fig. 3 shows a section of a further embodiment of a device for the thermal treatment of a material;

[0030] Fig. 4 is a diagram showing the nesting of two devices for providing a plasma;

[0031] Fig. 5 shows a section of another embodiment of a device for the thermal treatment of a material;

[0032] Fig. 6 shows a detail of an embodiment of a device for the thermal treatment of a material;

[0033] Fig. 7 shows another detail of the variant embodiment of the device for the thermal treatment of a material according to Fig. 6;

[0034] Fig. 8 shows a detail of an embodiment of a device for the thermal treatment of a material;

[0035] Fig. 9 shows another detail of the variant embodiment of the device for the thermal treatment of a material according to Fig. 8;

[0036] Fig. 10 shows a detail of an embodiment of a device for the thermal treatment of a material;

[0037] Fig. 11 shows another detail of the variant embodiment of the device for the thermal treatment of a material according to Fig. 10;

[0038] Fig. 12 shows a detail of an embodiment of a device for the thermal treatment of a material;

[0039] Fig. 13 shows another detail of the embodiment of the device for thermally treating a material according to Fig. 12; Fig. 14 shows another detail of the embodiment of the device for thermally treating a material according to Fig. 12;

[0040] Fig. 15 shows a detail of an embodiment of a device for the thermal treatment of a material;

[0041] Fig. 16 shows another detail of the variant of the device for the thermal treatment of a material according to Fig. 15.

[0042] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the position information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these position information must be applied analogously to the new position in the event of a change in position.

[0043] In Fig. 1, a device 1 for the thermal treatment of a material (hereinafter referred to as device 1) is shown in a simplified plan view.

[0044] The substance is, in particular, a solid, for example, a metal or a metallic alloy, e.g., steel or aluminum, or a ceramic solid. However, other substances, such as liquid substances, can also be thermally treated with device 1.

[0045] Thermal treatment is a treatment at a temperature above room temperature. Preferably, the thermal treatment does not result in any change in the physical state of the treated material. For example, the thermal treatment can be the annealing of a metal, e.g., a metal strip, a metal rod, or a metal tube, etc., to prepare the material for a further processing step, e.g., a forming step, or to enable recrystallization after a treatment step. This list is merely exemplary and should not necessarily be understood as limiting the invention.

[0046] The device 1 can, for example, be a roller hearth furnace. However, the device 1 can also be designed differently, as long as it is configured as described below. The device 1 comprises a treatment chamber 2 in which the material is located during the thermal treatment. The treatment chamber 2 has a housing 3, which is at least partially formed by a wall 4. The housing 3 can also have several of these walls 4. The wall 4 forms(s) in particular one or more side walls and / or a ceiling wall and / or a bottom wall of the housing 3.

[0047] The device 1 further comprises at least one device 5 for providing a plasma (hereinafter referred to as device 5), which provides thermal energy for the thermal treatment of the material. The device 5 can be designed, for example, as a microwave plasma torch, as described in WO 2021 / 170652 A1. The device 5 can generally be designed according to the prior art. In particular, the device 5 is an induction plasma torch (inductively coupled plasma).

[0048] The device 5 generates a plasma or a plasma stream, which subsequently generates a hot gas stream that is introduced into the treatment chamber 2. For this purpose, the device 5 comprises at least one plasma generation element (also referred to as a plasma torch). The plasma generation element has an element body (also referred to as a torch body). At least one electrical induction coil for plasma generation is arranged in or on the element body. Several induction coils can also be used, which can optionally be designed to be independently adjustable and / or controllable. The several induction coils can be arranged one behind the other in the flow direction of the gaseous fluid(s). Preferably, the device 5 is or comprises a so-called ICP torch (inductively coupled plasma). However, the device 5 can also be designed differently, for example as a DC plasma torch (direct current plasma).The multiple induction coils can be excited with the same frequency or with different frequencies.

[0049] Plasma generation can also be achieved in other ways, for example by means of a magnetron or generally with microwaves (for example generated by a solid-state microwave generator) or by means of two electrodes, etc.

[0050] Furthermore, a first flow channel for a first gaseous fluid and a concentrically arranged second flow channel for a second gaseous fluid can be arranged in the element body. The first and second flow channels can be tubular. The first flow channel can be arranged at a radial distance from the second flow channel. The distance can also be used to adjust, among other things, the velocity of the protective gas flow.

[0051] The first flow channel has a supply for a gaseous fluid and the second flow channel has a supply for a possibly different gaseous fluid.

[0052] For further details on plasma generation, in particular on an ICP torch, please refer to the relevant state of the art.

[0053] The device 1 can also have more than one device 5. For example, the device 1 shown in Fig. 1 has two such devices 5, one device 5 each on one of two walls 4, which in particular form the longitudinal side walls of the device 1 when the device 5 is designed as a continuous device, such as a roller hearth furnace. The embodiment of the device 1 shown in Fig. 1 has the devices 5 at one end of the device 1. However, the devices 5 can also be arranged centrally, as indicated by the dashed lines. Furthermore, it is possible to arrange more than one device 5 per wall 4, for example, between two and 10 devices per wall 4. The exact number of devices 5 depends on the length / size of the device 1 or the treatment chamber 2 and / or on the thermal energy requirement for treating the material in the device 1.

[0054] As can be seen from Fig. 1, not all walls 4 need to be provided with at least one device 5. The arrangement on walls running parallel to the direction of flow of the material through the device 1 is preferred if the most homogeneous temperature distribution possible in the treatment chamber 2 is desired.

[0055] If more than one device 5 is arranged, all devices 5 are preferably of the same design. Alternatively or additionally, the devices 5 can also be arranged on the ceiling wall and / or the bottom wall of the housing 3 of the treatment chamber 2.

[0056] The device 1 further comprises at least one hot gas channel 6. The hot gas channel 6 is arranged between the device 5 and the treatment chamber 2. The hot gas channel 6 has at least one inlet 7 (ie, an inlet opening) through which the hot gas generated by the device 5 is fed into the hot gas channel 6 or into or through which the plasma torch extends.

[0057] Furthermore, the hot gas channel 2 has at least two outlets 8 (outlet openings). The outlets 8 are arranged at a distance from one another. Accordingly, partial streams 9 of the hot gas stream from the hot gas channel 6 can be introduced into the treatment chamber 2 through the outlets 8. The number of partial streams 9 into which the hot gas stream is divided results from the number of outlets 8.

[0058] In the embodiment of the device 1 shown in Fig. 1, one hot gas channel 6 is arranged or formed for each device 5. However, it is also possible for more than one device 5 to be connected to a hot gas channel 6 or to be fluidly connected thereto.

[0059] Furthermore, Fig. 1 shows, in solid lines, that two outlets 8 for the hot gas are provided per hot gas channel 6. As can be seen from the dashed line in Fig. 1, more than two outlets 8 can be arranged or configured for supplying more than two partial flows 9 per device 5 and / or per wall 4 to which the at least one device 5 is assigned. It can be provided that the plurality of outlets 8 are distributed over the entire length of the respective wall 4 and arranged at a distance from one another.

[0060] As already explained above, more than one device 5 can be assigned to one wall 4 or more walls 4 of the housing 3 of the treatment chamber 2, wherein each of these devices 5 can be assigned its own hot gas channel 6 with at least two outlets 8. The respective design with regard to the number of devices 5, the number of hot gas channels 6, and the number of outlets 8 can depend on the type of thermal treatment of the material, the material itself, and / or the thermal energy requirement in the treatment chamber 2.

[0061] The device 1 can also have further components. These further components can be designed or constructed in accordance with the relevant prior art for such devices 1, so that for details, reference is made to this prior art. Figs. 2 to 16 show sections of further and possibly independent embodiments of the device 1, wherein the same reference numerals or component designations as in Fig. 1 are used for the same parts. To avoid unnecessary repetition, reference is made to the description of Fig. 1.

[0062] Fig. 2 shows a detail of a variant embodiment of the device 1. Specifically, the device 5 with a plasma generation element 10 can be seen, which is arranged on one of the walls 4 of the housing 3 of the treatment chamber 2. The hot gas channel 6 has the inlet 7 for the hot gas. The hot gas channel 6 further branches into four outlets 8, through each of which a partial stream 9 of the hot gas flows into the treatment chamber 2. Regarding the number of outlets 8, reference is made to the above explanations.

[0063] In this embodiment, at least one further hot gas stream is added to the hot gas stream generated by the device 5. For this purpose, the device 5 has at least one further inlet 7 for the further hot gas stream. Specifically, in Fig. 2, two further inlets 7 for the further hot gas stream are arranged or formed in the device 5. More than two further inlets 7 can also be present, for example three or four or five or six. The further inlet 7 or the further inlets 7 are arranged or formed in a side region of the device 5. If there is more than one further inlet 7, these are preferably distributed evenly over the circumference of the plasma generation element 10, for example in the 180 0 (see Fig. 2) or 120 0or 90°, etc., arranged offset from one another. It is also possible for the additional inlet 7 to be designed as an annular channel that completely surrounds the plasma generation element 10.

[0064] Alternatively or additionally, the further inlet 7 can also be arranged in the wall 4 in the housing 2, as shown in dashed lines in Fig. 2.

[0065] The additional hot gas stream is supplied via the at least one additional inlet 7 such that mixing with the hot gas stream generated by the plasma generation element 10 occurs. For this purpose, as shown in Fig. 2, the inlet 7 can have an inlet channel 11 that opens into the hot gas channel 6. The inlet channel 11 is, in particular, inclined to a longitudinal central axis 12 running through the plasma generation element 10, with an acute angle 13 being formed between the longitudinal central axis 12 and the inlet channel 11. The additional hot gas stream is therefore preferably supplied in the direction of the hot gas stream exiting the plasma generation element 10.

[0066] For better mixing of the hot gas stream with the further hot gas stream, the hot gas channel 6 can be formed with a mixing zone 14 in the area where the further hot gas stream is introduced, in which the hot gas channel 6 has a larger cross-section.

[0067] The additional hot gas supplied is preferably a gas that is also supplied to the plasma generation element 10 for generating the hot gas stream. The gas can be, for example, an inert gas such as argon or nitrogen, or a mixture thereof. However, it is also possible to use air, for example, provided the oxidizing properties of the hot gas do not interfere with the process with the material to be treated.

[0068] The additional hot gas preferably has a temperature that is lower than the temperature of the hot gas generated by the plasma generation element 10. In particular, the temperature of the additional hot gas is at most 80%, preferably at most 50%, for example, between 5% and 20%, of the temperature of the hot gas generated by the plasma generation element 10. For example, the hot gas can have a temperature between 7000°C and 10000°C. The additional hot gas can, for example, have a temperature between 500°C and 2000°C.

[0069] The additional hot gas flow allows the hot gas flow generated by the plasma generation element 10 to be "cooled," making the hot gas supplied to the treatment chamber 2 more adaptable to a wide variety of thermal treatments of materials. This makes it easier to achieve a "distribution of thermal power" at the desired temperature level among the multiple outlets 8. Furthermore, it makes it easier to operate a more powerful device 5 at a lower frequency, as already explained above.

[0070] The cooling of the hot gas from the device 5 with the further hot gas stream can be achieved by regulating the volume flow rates of hot gas and further hot gas. The further hot gas stream preferably has a larger volume flow rate than the hot gas stream in order to achieve a corresponding reduction in the temperature level, if this is desired with regard to the thermal treatment of the material in the treatment chamber 2. The specifically used volume flows therefore primarily depend on the desired temperature level of the thermal treatment. For example, the temperature in the hot gas can be 7000 °C. The temperature in the further hot gas can be 1000 °C. The desired mixing temperature (e.g. 1400 °C) can be set by regulating the volume flow ratio of hot gas to further hot gas.

[0071] The additional hot gas can be generated in a separate device for generating a hot gas. According to a preferred embodiment, however, the additional hot gas flow originates from the process itself. For this purpose, according to one embodiment, the treatment chamber 2 can have at least one outlet 15 (outlet opening), via which an exhaust gas from the treatment chamber 2 is fed back to the device 5 as additional hot gas, as shown schematically in Fig. 1. The at least one additional inlet 7 for the additional hot gas is connected to the at least one outlet 15 from the treatment chamber 2 via an additional hot gas channel 16 flow s.

[0072] Fig. 1 also shows a further embodiment of the device 1. To further reduce the temperature of the additional hot gas stream, at least one heat exchanger 17 can be arranged in the additional hot gas channel 16, with which thermal energy can be extracted from the additional hot gas originating from the treatment chamber 2. This thermal energy can optionally be used in a further process. The heat exchanger 17 can be designed according to the state of the art.

[0073] According to a variant of the embodiment, at least one further heat exchanger 16 can be arranged in the further hot gas channel 16, as can also be seen from Fig. 1.

[0074] In this embodiment, the two heat exchangers 17 can have heat storage elements which are formed, for example, by a material based on or with aluminum oxide (AI2O3), silicon dioxide (SiCh), iron(III) oxide (Fe2O3), titanium dioxide (TiCh), potassium oxide (K2O), calcium oxide (CaO), sodium oxide (Na2O), etc.

[0075] The heat storage elements serve to absorb heat from the exhaust gas from the treatment chamber 2, which is passed through the heat exchangers 17, and store it for later use. The two heat exchangers 17 can also be alternately supplied with the exhaust gas from the treatment chamber 2, allowing the heat storage elements of one heat exchanger 17 to be charged, while the heat storage elements of the other heat exchanger 17 can be used to generate the further hot gas flow.

[0076] It should be noted that gas conveying elements, such as a fan, etc., are not shown in Fig. 1.

[0077] If the additional hot gas is still too hot to be mixed with the hot gas generated by the plasma generation element 10, according to a variant of the device 1 it is possible to mix the additional hot gas with a cooler fresh gas before it is introduced into the device 5 or the hot gas channel 6.

[0078] The embodiment of the device 1 shown in Fig. 3 essentially corresponds to that of Fig. 2. The key difference is that in the embodiment shown in Fig. 2, the hot gas channel 6 is formed with cross-sectional extensions 18 immediately upstream of the outlets 8. This also increases the cross-section of the outlets 8, so that the hot gas stream (mixed with the further hot gas stream) or the partial streams 9 are introduced into the treatment chamber 2 over a larger area. This, in turn, allows a more even distribution of the supplied thermal energy in the treatment chamber 2.

[0079] In the preferred embodiment shown in Fig. 3, the cross-sectional extensions 18 are fan-shaped or trapezoidal in cross-section. However, the cross-sectional extensions 18 can also have a different shape.

[0080] The cross-sectional extensions 18 can be formed only immediately in front of the outlets 8, or they can be formed or arranged starting in deeper regions of the hot gas channel 6. For example, the cross-sectional extensions 18 can be formed starting in the areas where the hot gas channel 6 branches off to the outlets 8, as shown in Fig. 3.

[0081] In principle, the device 1 can have one or more devices 5, as already explained above. The illustration in Fig. 4 is intended to illustrate that it is possible to provide two devices 5 to increase performance. For better differentiation, the right-hand device 5 is provided with cross-hatching, while the left-hand device 5 has only single hatching.

[0082] The two devices 5 are each provided with several additional inlets 7 for the additional hot gas. These additional inlets 7 are arranged in a nested manner, as illustrated by the smaller circles in Fig. 4. This makes it possible to minimize the partial load range. The two devices 5 are switched on and off alternately, whereby a global power reduction can be achieved without reducing the power of the individual devices 5. By nesting the additional inlets 7, areas are also covered by both devices 5, so that even when the device 5 is switched off, the additional hot gas is still supplied to the section of the treatment chamber 2 assigned to the switched-off device 5.

[0083] In the embodiment of the device 1 according to Fig. 5, two or more further inlets 7 are provided for the additional hot gas. Control elements 19 are provided in the supply of the additional hot gas, i.e. in the additional hot gas duct 16. In the specifically illustrated embodiment, one control element 19 is provided for each inlet 7, with the additional hot gas duct 16 branching off upstream of the control elements 19. Alternatively, only one control element 19 can be used, which is arranged at the branching point. The arrangement downstream of the branching, however, has the advantage that, if required, both or more sections of the additional hot gas duct 16 downstream of the control elements 19 can be supplied with the additional hot gas simultaneously.

[0084] The adjusting element 19 or the adjusting elements 19 are designed in such a way that they set the section of the further hot gas channel 16 which follows in the flow path to "open" or "closed", so that the further hot gas can flow into this section or not, depending on the position. An adjusting element 19 can, for example, be a simple flap which can be adjusted between a closed position and an open position. If there is only one adjusting element 19, this can be designed as a three-way valve, for example. Designs are also possible in which the respective adjusting element 19, in an intermediate position between the closed and the open position, only allows a partial flow of further hot gas through.

[0085] As can be seen from Fig. 5, the hot gas channel 6 is already formed with cross-sectional extensions 18 from its beginning up to the outlet 8. This allows the hot gas flow exiting the plasma generation element 10 to be deflected along with the other hot gas flows, so that the hot gas flow is directed, for example, to the left or right (indicated by arrows in Fig. 5). This allows the thermal energy to be distributed over a larger section of the feed into the treatment chamber 2.

[0086] In Fig. 5, only one outlet 8 is provided for introducing the hot gas into the treatment chamber 2. This embodiment of the invention can be a stand-alone invention, since it enables distribution of the thermal power of the plasma generation element 10 over a larger section of the device 1 even without at least one additional outlet 8. However, even in this embodiment of the device 1, it can be provided that the hot gas channel 6 has a plurality of outlets 8, and that the hot gas flow is distributed alternately among the plurality of outlets 8 by means of the additional hot gas flows, in accordance with the above explanations.

[0087] Figs. 6 and 7 show sections of an embodiment of the device 1, which has two further embodiments. Firstly, in Fig. 6, which shows a section through the wall 4 of the housing 3 of the treatment chamber 2, on the outside of which the device 5 is arranged, the device 5 is arranged at an angle 20 of not equal to 90 0 to the wall 4 of the treatment chamber 2. In this way, the path of the hot gas in the hot gas channel 6 can be extended, thus enlarging the mixing zone 14 for mixing the hot gas from the device 5 or the plasma generation element 10 and the additional hot gas, and thus achieving better mixing of the hot gases.

[0088] The angle 20 is measured between the longitudinal central axis 12 through the plasma generation element 10 and the wall. In the present preferred embodiment, the device 5 is arranged with the plasma outlet extending obliquely downwards, since hot gas is known to rise. Thus, better heat distribution can be achieved with the entry of the hot gas stream into the treatment chamber. The oblique downward exit also has the advantage of delaying the direct impact of the hot gas stream on a wall 4.

[0089] Alternatively, however, the device 5 can be arranged with the plasma outlet extending obliquely upwards on the wall 4. The angle 20 can, for example, be between 10 0 and 80 °, especially between 20 0 and 60 °.

[0090] Fig. 7, which shows a view of the inner surface of the wall 4, shows that the outlet 8 and the at least one further outlet 8 (four further outlets 8 are shown in Fig. 7, although this number is not intended to be limiting) can have different cross-sections. For example, the central outlet 8 can have the smallest cross-section, while the two outer outlets 8 can each have the largest cross-section. The shape of the outlets can also be different. For example, the central outlet 8 can be circular, while the two outer outlets 8 can each have an oval or elongated shape.

[0091] With these design variants of the different size and / or shape of the outlets 8, the different pressure losses in the hot gas channel 6 can be taken into account, so that essentially the same volume flows of hot gas (and thus essentially the same thermal energy) emerge from the outlets 8 and can be introduced into the treatment chamber 2. Depending on the course of the hot gas channel 6, the shape and / or size of the at least two outlets 8 of the device 1 can also be different from those shown in Fig. 7.

[0092] In the embodiment of the device 1 shown in Fig. 6, the at least one device 5 is arranged on a rear side of the wall 4. As Figs. 8 and 9 show, the device 5 can also be arranged on an upper, lower, or lateral end face 21 of the wall 4. In the specific illustration, it is the upper end face 21.

[0093] Fig. 8 also shows a longitudinal section through the wall 4. As can be seen from the illustration, the hot gas duct 6 is again formed with the cross-sectional extension 18. One or more flow guide elements 22 are arranged in this cross-sectional extension 18. In general, at least one flow guide element 22 can be arranged in the hot gas duct 6. The arrangement of the flow guide element 22 is therefore not limited to the specific embodiment shown in Fig. 8.

[0094] The flow guide elements 22 can, for example, be baffles or have a web-shaped design. They can be formed integrally with the wall 4 or inserted into the hot gas duct 6 as separate components. In the specifically illustrated embodiment, the flow guide elements 22 are divided or arranged approximately in a fan-shaped manner. In addition, the flow guide elements 22 are of different lengths. The specific design of the flow guide elements 22 in this embodiment also depends on the specific design of the hot gas duct 6 or the outlets 8. In the illustrated embodiment, the multiple outlets 8 are "fused" to form a single slot-shaped outlet 8, as shown in the view of the inside of the wall 4 in Fig. 9. To prevent an exclusive central flow from being created with this design of the outlet 8, the flow guide elements 22 are arranged in the hot gas duct 6.

[0095] In general, the flow guide elements 22 can be used to direct the hot gas flow and / or divide the hot gas flow into several partial flows 9 (see, for example, Fig. 1). This simplifies the design of the hot gas channel 6, since a physical division of the hot gas channel 6 into several channel sections, as shown, for example, in the embodiments according to Figs. 2 and 3, may not be necessary.

[0096] Fig. 9 shows a further embodiment of the device 1 in dashed lines. In this case, at least one further flow guide element 23 is arranged in the treatment chamber 2, covering the outlet 8 and / or the at least one further outlet 8 and spaced from the outlet 8 and / or the at least one further outlet 8. This flow guide element 23 can, for example, be a baffle plate which prevents the hot gas flow from immediately or directly impacting the material to be thermally treated which is located in the treatment chamber 2. Essentially, the further flow guide element 23 can, for example, be a type of “baffle plate” which forces the hot gas flow emerging from the outlet 8 or the outlets 8 to change its flow direction.

[0097] A similar embodiment to the embodiment of the device 1 according to Figs. 8 and 9 is shown in Figs. 10 and 11. In this embodiment, however, another device 5 is arranged, so that two devices 5 feed the hot gas generated by them into the hot gas channel 6. Viewed from the plane of the paper, the boundary lines of the cross-sectional extension 18 of the hot gas channel 6 resemble the letter M. The outlet 8 is again slit-shaped (but, as with all embodiments, can also have a different shape). In order to achieve the most uniform possible flow of hot gas through the hot gas channel 6 in this embodiment as well, several flow guide elements 22 are arranged in the cross-sectional extension 18. The hot gas can be flowed through the hot gas channel with both devices 5 simultaneously, or alternately with the devices 5.If necessary, the embodiment variant described in Fig. 4 can also be used here.

[0098] In the above-described embodiments of the device 1, the hot gas channel 6 or the hot gas channels 6 (several or individual ones of the above-described embodiments can also be arranged per treatment chamber) are formed in the wall 4. The wall 4 is preferably made of a refractory material or has at least one refractory lining.

[0099] 12 to 14, it is also possible for the hot gas channel 6 or the hot gas channels 6 to be arranged partially on an outer side of the wall 4 of the housing 3 of the treatment chamber 2. This makes it possible to design the division into the partial flows 9 (see, for example, Fig. 1) in a structurally simpler manner by embodying the corresponding channel sections as simple bores or openings through the wall 4. The outer part of the hot gas channel 6 can be arranged covering these bores or openings to the outlets 8 on the inner side of the wall (Fig. 13) (Fig. 14). In this embodiment, the device 5 or the devices 5 is / are not connected directly to the wall 4, but via the outer part of the hot gas channel 6.

[0100] Here, too, other geometric designs of the outer part of the hot gas channel 6 are possible, so that the shape shown in Fig. 14 should not necessarily be understood as limiting.

[0101] Fig. 14 also shows that the multiple outlets 8 can all be designed the same.

[0102] A different embodiment, in comparison, but similar to the embodiments according to Figs. 8 to 11, is shown in Figs. 15 and 16. Again, the hot gas channel 6 has the two devices 5 arranged at the top of the wall 4, although this is only an example. There may also be only one device 5 or more than two devices 5. In this embodiment, the hot gas channel 6 also has the cross-sectional widening 18. However, there are no flow guide elements 22 in this. Instead, the inner side of the wall 4 facing the treatment chamber 2 is designed in the manner of a perforated plate with several outlets 8 arranged offset from one another. These outlets 8 can again be designed with different sizes and / or shapes to take account of the pressure loss in the hot gas channel 6. The pattern of the arrangement of the outlets 8 is also not limited to the illustration in Fig. 16. This can, among other things,according to the specific arrangement or design of the at least one device 5.

[0103] According to a further embodiment, the wall 4 of the treatment chamber 2, which has the outlet 8 or outlets 8 for the hot gas flow, can have a material with a lower thermal conductivity on an outer side than a material on an inner side. For example, the wall 4 can be made on the outside of, for example, lightweight refractory bricks, insulating bricks, fibers, lightweight refractory concrete, mats, panels, and vacuum-formed parts made of mineral wool, alkaline earth silicate fibers, aluminum silicate fibers, zirconium-reinforced silicate fibers, aluminum oxide fibers, and on the inside of, for example, fireclay, SiC ceramic, graphite, aluminum oxide, high-temperature steel, or can comprise these materials.

[0104] The hot gas duct(s) 6 conducting the flow can be made of the same material as the walls 4. According to a further embodiment, the hot gas duct(s) 6 conducting the flow can be made of a different material than the wall material. For example, the wall(s) 4 of the treatment chamber can be made of or comprise fiber materials which have a very good insulating effect. However, the fiber structure can cause problems when conveying media. To overcome this problem, a flow guide element (in the form of a channel, e.g., a tubular element) can be inserted into the respective wall 4, which, with the thinnest possible wall, can withstand the high temperatures of the hot gas flow to be introduced into the treatment chamber 2.For example, this flow guide element designed as a lining of the hot gas channel 6 can be a (fiber-reinforced) aluminum oxide, SiC, etc.

[0105] In general, the hot gas channel 6 can also have a spiral shape, at least partially or in sections, in order to achieve better mixing of the hot gas with the other hot gas. Furthermore, it can be provided that the device 1 has more than one treatment chamber 2 and that the device(s) 5 is / are assigned to more than one treatment chamber 2.

[0106] What all (described) embodiments of the device 1 have in common is that a plasma torch emerging from the device 5 does not reach into the treatment chamber 2, but only into the hot gas channel 6.

[0107] The embodiments show or describe possible embodiments of the device 1, whereby it should be noted at this point that combinations of the individual embodiments are also possible.

[0108] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure of facility 1, it is not necessarily shown to scale.

[0109] Reference symbol list

[0110] Furnishings

[0111] Treatment chamber

[0112] Housing

[0113] Wall

[0114] device

[0115] Hot gas duct

[0116] inlet

[0117] Outlet

[0118] Partial flow

[0119] Plasma generation element

[0120] Inlet channel

[0121] Longitudinal center axis

[0122] angle

[0123] mixed zone

[0124] Outlet

[0125] Hot gas duct

[0126] heat exchanger

[0127] Cross-sectional expansion

[0128] Actuator

[0129] angle

[0130] frontal surface

[0131] Flow guide element

[0132] Flow guide element

Claims

Patent claims 1. Device (1) for the thermal treatment of a substance, in particular a solid, comprising a treatment chamber (2), at least one device (5) for providing a plasma, and a hot gas channel (6), wherein the hot gas channel (6) is arranged or formed between the device (5) for providing a plasma and the treatment chamber (2) and has an inlet (7) for a hot gas stream generated by the device (5) for providing a plasma and an outlet (8) into the treatment chamber (2), characterized in that the hot gas channel (6) has at least one further outlet (8) for the hot gas stream into the treatment chamber (2) and / or that the hot gas channel (6) and / or the device (5) for providing a plasma has / have at least one further inlet (7) for a further hot gas stream.

2. Device (1) according to claim 1, characterized in that the further inlet (7) for the further hot gas flow is fluidly connected to a further hot gas channel (16), wherein the further hot gas channel (16) is fluidly connected to an outlet (15) from the treatment chamber (2).

3. Device (1) according to one of claims 1 or 2, characterized in that the hot gas channel (6) is formed with a cross-sectional widening (18).

4. Device (1) according to claim 3, characterized in that the cross-sectional extension (18) is fan-shaped.

5. Device (1) according to one of claims 1 to 4, characterized in that the outlet (8) and the at least one further outlet (8) have different cross-sections.

6. Device (1) according to one of claims 1 to 5, characterized in that at least one flow guide element (22) is arranged in the hot gas channel (6).

7. Device (1) according to one of claims 1 to 6, characterized in that at least one further flow guide element (23) covering the outlet (8) and / or the at least one further outlet (8) is arranged in the treatment chamber (2).

8. Device (1) according to one of claims 1 to 7, characterized in that the hot gas channel (6) is formed or arranged in the wall (4) or in a refractory lining of the wall (4) of the treatment chamber (2).

9. Device (1) according to one of claims 1 to 8, characterized in that the hot gas channel (6) is arranged partially on an outer side of the treatment chamber (2).

10. Device (1) according to one of claims 1 to 9, characterized in that at least one further device (5) for generating a plasma is connected to the hot gas channel (6).

11. Device (1) according to one of claims 1 to 10, characterized in that the hot gas channel (6) has at least one second further inlet (7) for a second further hot gas stream and that in each of the further and the second further hot gas streams an adjusting element (19) is arranged for interrupting the supply of the further hot gas into the hot gas channel (2) or into the device (5) for generating a plasma.

12. Device (1) according to one of claims 1 to 11, characterized in that the device (5) for generating a plasma at an angle (20) of not equal to 90 0 to the wall (4) of the treatment chamber (2).

13. Device (1) according to one of claims 1 to 12, characterized in that the outlet (8) of the hot gas flow into the treatment chamber (2) is slit-shaped.

14. Device (1) according to one of claims 1 to 13, characterized in that a wall (4) of the treatment chamber (2) which forms the outlet (8) for the hot gas flow has a material on an outside with a lower thermal conductivity than a material on an inside.

15. Device (1) according to one of claims 1 to 14, characterized in that at least one heat exchanger (17) is arranged in the feed for the further hot gas flow to the hot gas channel (6) and / or to the device (5).

16. Device (1) according to one of claims 1 to 14, characterized in that the hot gas channel (6) is lined at least in sections with a refractory material.

17. A method for the thermal treatment of a substance, in particular a solid, in a treatment chamber (2) with a hot gas stream which is generated in or with a device (5) for providing a plasma and is introduced into the treatment chamber (2) via a hot gas channel (6), characterized in that the hot gas stream is introduced into the treatment chamber (2) via a plurality of outlets (8).

18. The method according to claim 17, characterized in that the hot gas stream is mixed with another hot gas stream before being introduced into the treatment chamber (2).

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