Device for providing a plasma

Abstract

The invention relates to a device (6) for providing a plasma, comprising at least one plasma-generating element (8) with an inlet (46) and an outlet (47) for a gaseous fluid. The plasma-generating element (8) is equipped with a first flow channel (11) and optionally a second flow channel (12) that is concentric thereto and at least partly surrounds the first flow channel (11), wherein the first flow channel (11) is fluidically connected to a first connection (16) for a gaseous fluid in order to form a heated gas flow and / or a plasma flow, and the inlet (46) of the plasma-generating element (8) is fluidically connected to a conveyor element (34), by means of which the gaseous fluid can be accelerated.

Description

[0001] DEVICE FOR PROVIDING A PLASMA

[0002] The invention relates to a device for providing a plasma comprising at least one plasma generation element with an inlet and an outlet for a gaseous fluid, wherein a first flow channel is arranged in the plasma generation element, optionally a second flow channel arranged concentrically thereto, which surrounds the first flow channel at least in sections, wherein the first flow channel is fluidly connected to a first connection for a gaseous fluid for forming a heated gas flow and / or a plasma flow.

[0003] Furthermore, the invention relates to a device for the thermal treatment of a substance, in particular a solid, comprising at least one device for providing a plasma.

[0004] Furthermore, the invention relates to a method for operating a device for providing a plasma for generating a hot gas stream and / or a plasma stream for thermally treating a substance, comprising the steps of: supplying a gaseous fluid into a plasma generating element of the device, generating a plasma in the plasma generating element; providing a hot fluid stream through the plasma, optionally by heating the gaseous fluid with the plasma to produce a hot gas, wherein the hot fluid stream is directed outside the plasma generating element onto the substance to be treated.

[0005] The use of so-called plasma torches of various designs for melting substances, especially metals, is already documented in the state of the art.

[0006] 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.

[0007] From EP 1 433 366 A1, an inductive plasma torch is known comprising a tubular torch body with a proximal and a distal end, which further comprises an inner cylindrical surface with a first diameter, a plasma-enclosing tube made of a material having high thermal conductivity, which defines an axial chamber in which a high-temperature plasma is enclosed, and which has a cylindrical outer surface with a second diameter slightly smaller than the first diameter, wherein the plasma-enclosing tube is mounted within the tubular torch body and the cylindrical inner and outer surfaces are coaxially aligned to form a thin annular chamber of equal thickness between the inner and outer surfaces, a gas distribution head mounted at the proximal end of the torch body,to introduce at least one gaseous substance into the axial chamber defined by the plasma confining tube, a cooling fluid source connected to the thin annular chamber to establish a high-velocity cooling fluid flow in the annular chamber, wherein both the high thermal conductivity of the material from which the plasma confining tube is made and the high-velocity flow of the cooling fluid efficiently contribute to the heat transfer from the plasma confining tube into the cooling fluid, thereby efficiently cooling the plasma confining tube, a first power supply with a higher frequency output, a second power supply with a lower frequency output, having first and second terminals, a series of induction coils,which are arranged on the tubular burner body substantially coaxially to the tubular burner body between the proximal and distal ends of the burner body, comprising a first induction coil connected to the higher frequency output of the first power supply for inductively applying energy to at least one gaseous substance fed into the axial chamber, and a plurality of second induction coils arranged between the first induction coil and the distal end of the tubular burner body, the second induction coils each having corresponding terminals, and a connecting circuit arranged between first and second terminals of the lower frequency output of the second power supply and the terminals of the second induction coils for interconnecting the second induction coils in a series and / or parallel circuit between the first and second terminals,to match an input impedance of the second induction coils to an output impedance of the second power supply, and to inductively apply energy to the at least one gaseous substance fed into the axial chamber.

[0008] 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 sufficient to at least melt the solid.

[0009] From DE 69216970 T2, an induction plasma torch is known, comprising: a tubular torch body including a cylindrical inner surface with a first diameter; a plasma containment tube made of heat-conducting ceramic material and including a first end, a second end, and a cylindrical outer surface having a second diameter smaller than the first diameter; wherein the plasma containment tube is mounted in the tubular torch body and forms an annular chamber between the cylindrical inner and outer surfaces; a gas distributor mounted on the tubular torch body at the first end of the plasma containment tube and supplying at least one gaseous substance to the plasma containment tube, wherein the at least one gaseous substance flows through the plasma containment tube from its first end toward its second end;an induction coil to which an electric current is supplied for inductively supplying energy to the at least one gaseous substance flowing through the plasma containment tube to produce and maintain plasma in the containment tube, wherein the induction coil is coaxial with the cylindrical inner and outer surfaces of the annular chamber; and means for producing a flow of cooling fluid in the annular chamber; wherein the induction coil is embedded in the tubular torch body, and the cylindrical inner and outer surfaces are machined and coaxial so that the annular chamber has a uniform thickness. EP 3 314 989 B1 describes an induction plasma torch comprising: a tubular torch body having an upstream region and a downstream region, the upstream and downstream regions defining respective inner surfaces;and a plasma confinement tube provided within the tubular torch body, coaxial with the tubular torch body and having an inner surface of constant inner diameter and an outer surface; and a tubular insert mounted on the inner surface of the downstream region of the tubular torch body, the tubular insert having an inner surface; and an annular channel defined between the inner surface of the upstream region of the tubular torch body and the inner surface of the tubular insert, and the outer surface of the plasma confinement tube, the annular channel configured to carry a cooling fluid for cooling the plasma confinement tube; and the plasma confinement tube having a tubular wall with a thickness tapering over at least a portion of the plasma confinement tube in an axial direction of plasma flow.

[0010] EP 2 671 430 B1 describes an induction plasma torch comprising: a tubular torch body having an inner surface; a plasma confinement tube arranged coaxially with the tubular torch body in the tubular torch body, the plasma confinement tube having an outer surface; a gas distribution head arranged at one end of the plasma confinement tube and structured to supply at least one gaseous substance into the plasma confinement tube; an inductive coupling element for applying energy to the gaseous substance to generate and maintain plasma in the plasma confinement tube;and a capacitive shield comprising a layer of conductive material applied to the outer surface of the plasma confinement tube or the inner surface of the tubular torch body, wherein the layer of conductive material is segmented into axial strips, and the axial strips are connected to one another at one end, and wherein the inductive coupling element is embedded within the tubular torch body and axial grooves are formed in the outer surface of the plasma confinement tube or the inner surface of the tubular torch body, wherein one of the axial grooves is arranged between a pair of laterally adjacent axial strips. The object of the present invention is to provide an improved possibility for the thermal treatment of a material.

[0011] The object of the invention is achieved in the device for providing a plasma mentioned at the outset in that the inlet of the plasma generation element is fluidly connected to a conveying element with which the gaseous fluid can be accelerated.

[0012] Furthermore, the object of the invention is achieved with the device for thermal treatment of a substance mentioned at the outset, which has the device according to the invention for providing a plasma.

[0013] Finally, the object of the invention is achieved by the method mentioned at the outset, according to which the gaseous fluid is accelerated before being fed into the plasma generation element.

[0014] The advantage here is that the acceleration can improve the introduction of the gaseous fluid into the plasma generation element. This, in turn, can prevent overheating of the plasma generation element and / or the device on which the plasma generation element is arranged, and / or the substance to be thermally treated in the region of the plasma. Acceleration is particularly advantageous when a mixture of gaseous fluids, such as preferably a recycle gas and a fresh gas, is supplied to the plasma generation element, since the other gas stream can also be "entrained" with the accelerated gas stream. In addition, the pressure increase that may accompany the acceleration can create overpressure in the system, which prevents the penetration of oxygen-containing gases from the environment of the device and thus also prevents oxidative problems in the device for the thermal treatment of a substance that has the device.

[0015] According to one embodiment of the invention, the plasma generation element can be connected to a gas supply device. This allows for easier provision of the gaseous fluids or simpler volume flow control of the supply of these gaseous fluids to the plasma generation element. According to one embodiment, the gas supply device can have a fresh gas supply and / or a recirculating gas supply for a recirculating gas, which can simplify the gas flow in the system, particularly when gaseous fluid is supplied to the plasma generation element at several different locations.

[0016] According to one embodiment of the invention, the conveying element is preferably arranged in a recirculating gas duct for the recirculating gas, which is connected to the outlet of the plasma generation element. Since the proportion of recirculating gas in the device should be maximized as much as possible in order to improve the energy balance, this embodiment can further improve the aforementioned effects.

[0017] According to a further embodiment of the invention, the conveying element can be a jet pump. This has the advantage that the gaseous fluid, in particular the recycle gas, can be hotter, since a jet pump can be operated without moving parts.

[0018] According to a further embodiment of the invention, the jet pump can be provided with a propellant connection connected to the fresh gas supply. The fresh gas supplied to the plasma generation element can thus also assume the function of the propellant, thus achieving cost reduction by reducing the required fluid quantities.

[0019] According to a further embodiment, it can be provided that the jet pump is a controllable jet pump with a control of the volume or quantity flow of fresh gas, whereby the control and / or regulation of the device for generating a plasma and the device for thermally treating a substance can be simplified.

[0020] According to another embodiment of the invention, the inlet of the plasma generation element can be fluidly connected to another fresh gas supply. This makes it possible to reduce the volume flow of fresh gas in the jet pump while maintaining a constant volume flow of circulating gas. On the other hand, other conveying elements can also be used to circulate the circulating gas. It is advantageous if, according to one embodiment of the invention, a heat exchanger is arranged upstream of the conveying element in the flow direction of the gaseous fluid, since this allows the temperature of the gaseous fluid to be reduced and, as a result, conveying elements with less thermal load, such as a fan, can be used. The heat exchanger also allows the energy extracted from the gaseous fluid to be reused.

[0021] It is also advantageous if, according to a further embodiment of the invention, an additional heat exchanger is arranged in the additional fresh gas supply, so that the fresh gas can be introduced into the plasma generation element at a higher temperature. The use of a heat exchanger makes it possible to utilize waste heat from another process.

[0022] According to one embodiment of the invention, the additional heat exchanger can be connected to the heat exchanger upstream of the conveying element flow s, so that preheating can be carried out using the waste heat from the process itself. The distance between the heat exchangers is comparatively small, which can improve the energy balance of the device or apparatus according to the invention.

[0023] According to another embodiment of the invention, the conveying element can also be a fan or a turbine, which makes it possible to dispense with the supply of a driving fluid, but at the same time enables good controllability of the volume flow.

[0024] In order to influence the process conditions, according to one variant of the process, another gaseous fluid can be added to the gaseous fluid.

[0025] According to a further variant of the process, the additional gaseous fluid can also be used to adjust or control the temperature and / or the angle of a plasma torch. This can minimize local temperature increases and improve overall heat transfer.

[0026] According to one embodiment of the method, the plasma can be generated inductively using at least one electrical induction coil. Furthermore, the temperature of the induction coil and / or a temperature increase of a cooling fluid for the induction coil and / or a temperature change of the wall of the plasma generation element in the region of the hot gas outlet is measured. Based on this measured value, the volume flow of the central gas stream is changed in response to a temperature change. The efficiency of the device for generating a plasma can thus be improved, for example, by increasing or reducing the volume flow proportion of recirculating gas.

[0027] For the above reasons, it is advantageous if, according to an embodiment of the method, it is provided that this further comprises the steps of supplying a fresh gas stream to a gas supply device of the plasma generation element, supplying a recirculating gas stream from a treatment chamber in which the material is thermally treated to the gas supply device, wherein a jet pump is used for supplying the recirculating gas stream, which is operated with a fresh gas stream as propellant gas.

[0028] According to one embodiment of the method, it can be provided that the volume flow of the recycle gas flow is regulated with the volume flow of fresh gas that is fed to the jet pump, which can subsequently influence the temperature in the treatment chamber for the material to be thermally treated.

[0029] For a better understanding of the invention, it is explained in more detail using the following figures.

[0030] They show in a simplified, schematic representation:

[0031] Fig. 1 shows a device for the thermal treatment of a material;

[0032] Fig. 2 shows a section of a device for providing a plasma;

[0033] Fig. 3 shows a section of a variant embodiment of a device for providing a plasma;

[0034] Fig. 4 shows a section of a further embodiment of a device for providing a plasma;

[0035] Fig. 5 shows a section of a further embodiment of a device for providing a plasma; Fig. 6 shows an arrangement of several plasma generation elements;

[0036] Fig. 7 shows another arrangement of several plasma generating elements;

[0037] Fig. 8 a jet pump in longitudinal section;

[0038] Fig. 9 shows a section of a variant embodiment of the device for providing a plasma;

[0039] Fig. 10 shows an embodiment of a device for the thermal treatment of a material;

[0040] Fig. 11 shows a further embodiment of a device for the thermal treatment of a material.

[0041] 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 positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0042] In the following, a first and a second gaseous fluid, as well as a further gaseous fluid, are listed. These fluids can be different gases or the same gases. Furthermore, the gaseous fluids can be pure gases or gas mixtures.

[0043] In addition, the terms fresh gas, recycle gas, exhaust gas, and process gas (also referred to as plasma gas) are used below. The fresh gas and the process gas can be formed by at least one of the gaseous fluids mentioned in the previous paragraph. The recycle gas, as the name suggests, is circulated in the device according to the invention and reused for plasma generation. It is therefore transformed from exhaust gas back into process gas.

[0044] Furthermore, the terms "hot fluid" and "hot fluid stream" are used in this description. These terms are used for both a plasma stream that is directed directly onto a material to be treated and a hot gas stream, i.e., a gas stream heated by a plasma and subsequently directed onto the material to be treated or used for thermal treatment of the material.

[0045] Any gas suitable for forming a plasma can be used as gaseous fluids, such as nitrogen, argon, neon, xenon, air, carbon dioxide, carbon monoxide, hydrogen, gaseous water, or a mixture of at least two of these gases.

[0046] Fig. 1 shows a device 1 for the thermal treatment (hereinafter referred to as device 1) of a substance 2.

[0047] Substance 2 can be a liquid or a gas. However, substance 2 is preferably a solid, in particular a metallic solid.

[0048] The thermal treatment can be the melting of the substance 2 or the tempering of the substance 2, for example, maintaining a certain temperature, or heating the substance 2. However, the thermal treatment can also comprise a chemical reaction carried out at an elevated temperature. This list of possible uses of the device 2 is to be understood as examples only, with the melting of a metallic solid being one of the preferred applications.

[0049] Since the fields of application of the device 1 are different, the schematic representation in Fig. 1 is not to be understood as limiting, but only as illustrating the invention.

[0050] The device 1 comprises a receptacle 3 for the substance 2. The receptacle 3 can be formed by a separate container in which the substance 2 is located. In the case of a gas, or in general, the receptacle 3 can also be merely a housing 4 of a treatment chamber 5 or a chamber of the treatment chamber 5 in which the substance 2 is located for the thermal treatment. The aforementioned separate container, if present, is also arranged in the treatment chamber 5.

[0051] For the sake of completeness, it should be noted that more than one receptacle 3 for the substance 2 can be arranged in the treatment chamber 5, wherein different substances 2 can also be accommodated in the receptacles 3, for example in order to carry out a chemical reaction. Furthermore, the device 1 comprises a device 6 for providing a plasma (hereinafter referred to only as device 6), with which the thermal energy for the thermal treatment of the substance 2 is provided. The device 6 is arranged on the housing 4 of the treatment chamber 5 in such a way that a plasma torch or a plasma stream or a hot gas stream 7, which is generated with the plasma from the process gas, extends into or towards the treatment chamber 5.

[0052] For further components of device 1 which are not mentioned or explained below, reference is made to the relevant state of the art in order to avoid repetition.

[0053] The device 6 comprises at least one plasma generating element 8.

[0054] A variant of the plasma generation element 8 (also referred to as a plasma torch) is shown in Fig. 2 in a partial longitudinal section.

[0055] The plasma generation element 8 has an element body 9 (also referred to as a torch body). At least one electrical induction coil 10 for plasma generation is arranged in or on the element body 9. Multiple induction coils 10 can also be used, which can optionally be configured to be independently adjustable and / or controlled. The multiple induction coils 10 can be arranged one behind the other in the flow direction of the gaseous fluid(s).

[0056] 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.

[0057] Furthermore, a first flow channel 11 for a first gaseous fluid and a concentrically arranged second flow channel 12 for a second gaseous fluid are arranged in the element body 9. The first flow channel 11 is arranged at least in sections, for example in the region above or a partial region of the arrangement of the induction coil 10, within the second flow channel 12. The first and second flow channels 11, 11 can be tubular, for example with a circular cross-section. The first and / or second flow channels 11, 11 can be formed, for example, from a quartz glass tube or an aluminum oxide tube or a boron nitride tube, etc. The second flow channel 12 can be arranged at a distance 13 from a surface 14 of the element body 9 (in particular that surface 9 behind which the induction coil 10 is arranged), which distance is selected from a range from 0 mm to 30 mm, in particular from 0 mm to 20 mm.

[0058] The first flow channel 11 can be arranged at a radial distance 15 from the second flow channel 12, which is selected from a range of 0.1 mm to 40 mm, in particular 0.4 mm to 30 mm. The distance can also be used to adjust, among other things, the velocity of the protective gas flow 20.

[0059] The first flow channel 11 has a first connection 16, i.e., a first supply, for the first gaseous fluid, and the second flow channel 12 has a second connection 17, i.e., a second supply, for the second gaseous fluid. As can be seen from Fig. 2, the first and second connections 16, 17 can be fed by a common supply line 18 for the gaseous fluids. However, completely separate / independent supplies for the first and second gaseous fluids can also be provided.

[0060] The first gaseous fluid is fed to the first flow channel 11 via the first connection 16 to form a heated gas flow (central gas flow 19). The second gaseous fluid is fed to the second flow channel 12 via the second connection 17, which forms a protective volume flow (shielding gas flow 20) between the surface 14 of the plasma generation element 8, i.e., the element body 9, and the heated gas flow or plasma flow. Both gas flows, i.e., the central gas flow 19 and the shielding gas flow 20, leave the plasma generation element 8 together via an outlet 21, i.e., an outflow opening, to be available for the thermal treatment of the material 2.

[0061] It should be noted that the representation of the plasma generation element 8 in Fig. 2 is exemplary in nature. The specific arrangement of the individual elements in the plasma generation element 8 can also be designed differently, as long as the functionality is maintained.

[0062] In Fig. 3 is shown a further and possibly independent embodiment of the

[0063] Plasma generation element 8 is shown in longitudinal section and schematically, wherein again the same reference numerals or component designations are used for the same parts as in Figs. 1 and 2. To avoid unnecessary repetition, reference is made to the preceding description.

[0064] As can be seen from Fig. 3, the first flow channel 11 ends at a distance from the outlet 21 of the plasma generation element 8, which, among other things, improves the effect of the induction coil 10 on the central gas flow 19. The specific distance to the outlet 21 depends on the respective design of the plasma generation element 8.

[0065] It can also be seen that no separate channel element (pipe) is used for the second flow channel 12, but that, according to one embodiment of the plasma generation element 8, the second flow channel 12 is delimited outwards by the surface 14 of the element body 9 of the plasma generation element 8, i.e., is formed by the plasma generation element 8 itself. Alternatively, it can be provided that the second flow channel 12 is formed by its own channel element 22, as is the case in the embodiment according to Fig. 2 and shown in dashed lines in Fig. 3, but that this channel element 22 is arranged directly adjacent to the surface 14 of the element body 9. If necessary, this channel element 22 can also be formed as a coating on the surface 14 of the element body 9. The coating can, for example, be formed at least partially from silver, gold, aluminum, etc.Of course, the spaced arrangement of the channel element 22 shown in Fig. 2 is also possible in the embodiment variant of the plasma generation element 8 according to Fig. 3.

[0066] From Fig. 3, it can also be seen that the induction coil 10 can be arranged at a short distance from the surface 14 of the element body 9. Furthermore, it can be seen from Fig. 3 that the induction coil 10 can be designed to be cooled, for which purpose it can have a cooling channel 23. Water, cooling oil, etc., can be used as the cooling medium that can flow through the cooling channel 23.

[0067] In the embodiment of the plasma generation element 8 according to Fig. 3, it is provided that at least one further flow channel 24 is arranged or formed in the plasma generation element 8. For example, the further flow channel 24 can be formed in the element body 9 of the plasma generation element 8. The further flow channel 24 is connected to a further connection 25 for a further gaseous fluid flow s. If necessary, the further connection 25 can also be connected to the supply line 18 (see Fig. 2), so that all three gaseous fluids have the same composition. However, a completely independent supply of the further gaseous fluid, independent of the supplies of the first and second gaseous fluids, is also possible.

[0068] As can be seen from Fig. 3, the further flow channel 24 is designed to run obliquely to the first flow channel 11 and to the second flow channel 12, wherein an angle 26 between the flow channels 11 or 12 and 24 is designed such that a flow direction of a gas flow formed by the third fluid, in particular a cooling gas flow 27, runs in the direction of the center or in the direction of a longitudinal center axis 28.

[0069] In Fig. 3, the additional flow channel 24 runs at the same angle of inclination over its entire length in the plasma generation element 8, i.e., in the element body 9. However, it can also be provided that only one end section is designed to run obliquely at the angle 26. The end section begins at an outlet opening 29 of the additional flow channel 24 in the plasma generation element 8. Therefore, the additional flow channel 24 can be designed with different angles of inclination over its length, or the additional flow channel 24 can also have a curved shape.

[0070] The additional flow channel 24 enables the supply of the additional gaseous fluid to change the temperature of the hot gas stream 7 or plasma stream formed from the shielding gas stream 20 and the central gas stream 19. If necessary, the position of the hot gas stream 7 or the plasma stream or the plasma torch can also be changed.

[0071] According to a preferred embodiment of the plasma generating element 8, the angle 26 which at least the end section of the further flow channel 24 encloses with the first and second flow channels 11, 12 can be selected from a range of 10 0 and 80 °, in particular from a range of 15 0 to 70 °. For example, the angle can be 26 20 0 or 30 0 or 40 0 or 45 0 or 50 0 or 60 0 be.

[0072] It is possible within the scope of the invention for only a single further flow channel 24 to be formed. As shown in Fig. 4, which shows a top view of a section of an embodiment variant of the plasma generation element 8 in cross section, a plurality of further flow channels 24 can be provided, for example four or only two or three or more than four, for example five or six, etc. The plurality of further flow channels 24 are arranged distributed along a circumference (or circumference) defined by the second flow channel 12, in particular evenly distributed or symmetrically distributed. Webs 30 of the element body 9 can be formed between the individual further flow channels 24.

[0073] It should be mentioned at this point that the second flow channel 12 can also be divided into several second flow channels 12, which are arranged distributed over the circumference of the first flow channel 11.

[0074] Each of the several further flow channels 24 extends - as shown in Fig. 4 - over a circular ring segment (or a circular ring section). According to one embodiment of the plasma generation element 8, the circular ring segments can be selected from a range of 2 0 to 88 °. For example, the circular ring segments can extend over a range of 10 0 up to 80 0 or a range of 20 0 to 70 °. However, a single circular ring segment can also extend over a range of 10 0 up to 358 0 In general, circular ring segments can extend over a range of 2 0 up to a value that is divided by 360 “ / number of circular ring segments - 1 0 is defined, in particular up to a value defined by 360 " / number of circular ring segments - 5 °.

[0075] The multiple circular ring segments can all have the same length in the circumferential direction. However, at least one of the circular ring segments can also have a different length in the circumferential direction than the other circular ring segments.

[0076] As can be seen from Fig. 1, according to a further embodiment of the device 6, it is possible for it to have a gas supply device 31. It is possible for the plasma generation element 8 to be supplied not only with the first gaseous fluid, but also with the second and the further gaseous fluid from the gas supply device 31, as indicated by dashed lines in Fig. 1.

[0077] For this purpose, the first connection 16 for the first gaseous fluid and the second connection 17 for the second gaseous fluid and / or the further connection 25 for the further gaseous fluid can be connected to the gas supply device 31 flow s.

[0078] However, it is also possible for some or each of the connections 16, 17, and 25 to be fluidly connected to a dedicated gas supply device 31. Thus, the first connection 16 for the first gaseous fluid, the second connection 17 for the second gaseous fluid, and the further connection 25 for the further gaseous fluid can each be supplied with the same gaseous fluid, or at least two of them, or all of them can be supplied with different gaseous fluids. For example, the first connection 16 can be supplied with a fresh gas, and the second connection 17 and / or the further connection 25 can be supplied with a recycle gas. Accordingly, according to a further embodiment of the device 6, at least one fresh gas supply 32 and at least one recycle gas supply 33 can open into the gas supply device 31 to provide at least a portion of at least one of the gaseous fluids, as shown in Fig.1 is shown in dashed lines. The recycle gas supply is connectable to the device 1 for thermally treating the material 2, in particular a furnace, into which the hot gas or plasma generated by the plasma generation element 8 can be introduced.

[0079] According to another embodiment of the device 6, it can be provided that the recycle gas is introduced directly into the plasma generation element 8, without the detour via the gas supply device 31, as shown in solid lines in Fig. 1.

[0080] According to another embodiment of the device 6, at least one conveying element 34, for example a jet pump, for the recycle gas can be arranged in the recycle gas supply. Regarding the conveying element 34, reference is also made to the following explanations.

[0081] According to a further embodiment of the device 6, it can be provided that the plasma generation element 8 has a connection 35 for an ignition gas 36, for example argon, in order to improve or accelerate the formation of the plasma or to be able to feed less suitable gases for providing the plasma into the device 6.

[0082] According to one embodiment of the device 6, it can also be provided that at least one heat exchanger 37 for heating the newly supplied gaseous fluid (the fresh gas) is arranged in the fresh gas supply 32. The heat exchanger can be designed according to the prior art. It should be noted at this point that in Fig. 1, the fresh gas supply 32 is connected to the gas supply device 31. However, it can be provided that, alternatively or additionally, the fresh gas supply 32 is connected directly to the plasma generation element 8, as shown in dashed lines in Fig. 1.

[0083] In Fig. 5, a further and possibly independent embodiment of the plasma generation element 8 is shown in longitudinal section and schematically, wherein again the same reference numerals or component designations are used for the same parts as in Figs. 1 to 4. To avoid unnecessary repetition, reference is made to the above description.

[0084] In this embodiment of the device 6 or the plasma generation element 8, it is provided that the first flow channel 11 and / or the second flow channel 12 have a reflective coating 38 on the inside. This coating 38 can extend over the entire length or only a portion of the length of the first flow channel 11 and / or the second flow channel 12, for example, only in an initial region or an end region and / or a central region of the first flow channel 11 and / or the second flow channel 12. The coating 38 can also consist of differently composed sections in order to better correspond to the temperature distribution in the plasma generation element 8, since the radiation maxima occur at different wavelengths depending on the temperature. Thus, the radiation maxima shift to shorter wavelengths at higher temperatures.In this way, a material can be selected for coating sections based on the respective wavelength or wavelength range, which is particularly effective at the respective peak of the radiation. For example, at shorter wavelengths, an aluminum coating may be more effective than one made of gold or silver. At longer wavelengths, the opposite may be true.

[0085] The coating 38 can be metallic, for example. For example, the coating 38 can be formed from silver, gold, platinum, aluminum, or an alloy containing at least one of these metals. This makes it possible, among other things, to adjust, change, or increase the quantity of reflected radiation and / or the wavelength range of the reflected radiation. In particular, alloys or alloying elements can also be used to cover the wavelength range of the reflected radiation to wavelengths of less than 500 nm or less than 200 nm in order to increase the proportion of reflected radiation in this wavelength range.

[0086] In addition to the circumferential, full-surface coating 38, according to one embodiment variant, it is also possible to form it in stripes or columns, as indicated in Fig. 5 by the dashed stripes 39. The stripes 39 can have a width in the circumferential direction of the first flow channel 11 or the second flow channel 12 that is selected from a range between 0.1% and 20%, in particular between 1% and 10%, of the circumference of the first flow channel 11 or the second flow channel 12.

[0087] The strips 39 can be arranged at a distance 40 from one another which is selected from a range between 0.1% and 20%, in particular between 1% and 10%, of the circumference of the first flow channel 11 or the second flow channel 12.

[0088] It can further be provided that only a partial area of ​​the circumference or the entire circumference is provided with spaced-apart strips 39 of the first flow channel 11 or the second flow channel 12.

[0089] The strips 39 can all be made of the same material. However, they can also be made of different materials; for example, strips 39 made of metals with different reflectivity can be combined in a plasma generation element 8. Different materials can also be provided for the continuous coating 38 by forming it in sections from different materials, as explained above.

[0090] The strips 39 have a longitudinal extension in the direction of the longitudinal center axis 28 through the first flow channel 11. According to a variant of this embodiment, the strip shape of the coating 38 can also be achieved by one or more helical formations, whereby here, too, distances can be formed between the coated sections (e.g., in the form of a helical, uncoated section).

[0091] The strips 39 can be designed as a coating 38. However, they can also be manufactured as separate components and subsequently connected to the first flow channel 11 or the second flow channel 12. The same applies to the coating 38 itself, in that it is manufactured as a tube and this is inserted into the first flow channel 11 or the second flow channel 12. Furthermore, it is possible for the first flow channel 11 or the second flow channel 12 to be made of a correspondingly reflective material or with a correspondingly reflective surface, e.g., due to a surface structure.

[0092] In Figs. 6 and 7, further and possibly independent embodiments of the device 6 are shown schematically and in sections, wherein again the same reference numerals or component designations are used for the same parts as in Figs. 1 to 5. To avoid unnecessary repetition, reference is made to the above description.

[0093] In the preceding explanations of the device 6, it always had only one plasma generating element 8. However, it is also possible for multiple plasma generating elements 8 to be arranged in the device 6. For this purpose, embodiments with three and five plasma generating elements 8, respectively, are shown as examples in Figs. 6 and 7. Only two or four or more than five, for example, six, etc., plasma generating elements 8 can also be arranged in a device 6.

[0094] The plasma generation elements 8 can all have the same heating power or a different heating power, as indicated in Figs. 6 and 7 with different sizes of the plasma generation elements 8. It should be noted again that the specific illustrations are intended as examples. Other designs are also possible, such as three plasma generation elements 8 with the same heating power and one plasma generation element 8 with a comparatively lower heating power, for example, to be able to compensate for peak loads with this "smaller" plasma generation element 8.

[0095] For example, with three plasma generation elements 8, each with a maximum power of 300 kW (with three power inputs into the gaseous fluid), it can be provided that at a desired power of 900 kW, the plasma generation elements 8 are operated at 100% power (300 kW each), or that at a desired power of 700 kW, the plasma generation elements 8 are operated at 78% power each, or that at a desired power of 600 kW, two plasma generation elements 8 are operated at 100% power each and the third at 0% power, or that at a desired power of 300 kW, one plasma generation element 8 is operated at 100% power each and the other two at 0% power. It can also be provided that at a maximum load of 400 kW, two plasma generation elements 8 are operated at 100% power and one plasma generation element 8 is operated at 25% power.It can be provided that at a maximum load of 400 kW, two plasma generation elements 8 are operated at 0% power and one plasma generation element 8 is operated at 25% power in order to obtain 100 kW of desired power.

[0096] Please note that these examples are for illustrative purposes only and are not limiting.

[0097] The plurality of plasma generation elements 8 can all be designed identically, so that the statements regarding the plasma generation element 8 in this description can be applied to all plasma generation elements 8.

[0098] According to one embodiment of the device 1, it can be provided that the treatment chamber 5 is connected to an exhaust line 41 flow s, wherein at least one flap 42 and / or at least one slide valve and / or at least one cross-sectional tapering element 43 is / are arranged in the exhaust line 41. The cross-sectional tapering element 43 can be designed, for example, as a diaphragm, optionally an adjustable diaphragm with a variable diameter of the through-opening.

[0099] With the at least one flap 42 or the at least one slide or the at least one cross-sectional tapering element 43, it is possible to control or regulate the volume flow of the exhaust gas leaving the device 1 via a discharge element 44, e.g. a chimney.

[0100] The remainder of the exhaust gas becomes recycle gas and can be fed back into the process as such via the recycle gas supply 32. The portion that leaves the device 1 through the discharge element 44 can be replaced with fresh gas via the fresh gas supply 33. Thus, the volume flow ratio of recycle gas to fresh gas can be controlled and / or regulated by means of the at least one flap 42 and / or the at least one slide valve and / or the at least one cross-sectional tapering element 43. Furthermore, pressure regulation of the pressure in the treatment chamber 5 is also possible. According to a further embodiment of the device 1, also shown in Fig. 1, it can be provided that the treatment chamber 5 and / or the device 6 for providing a plasma has / have a supply device 45 for introducing solid particles that increase the thermal radiation.This feed device 45 can, for example, be a nozzle, so that the solid particles can be finely distributed into the treatment chamber 5 or the plasma generation element 8, or generally into the device 6. The feed device 45 can also be designed differently.

[0101] The solid particles can be formed from graphite or a metal such as iron, copper, or aluminum. Solid particles that react with the substance 2 in the treatment chamber 5, for example, to form an alloy, can also be used. The solid particles can, for example, have an average particle size between 0.1 pm and 1000 pm.

[0102] The device 6 can provide a plasma that can heat a gas stream, so that the resulting hot gas stream 7 or the plasma stream itself can be used for the thermal treatment of a substance 2. For this purpose, a gaseous fluid is introduced into at least one plasma generation element 8 of the device 6, and a plasma is generated in the plasma generation element 8. For better protection of the plasma generation element 8, the gaseous fluid in the plasma generation element 8 is guided in the form of a central gas stream 19 surrounded by a protective gas stream 20.

[0103] It can be provided that a further gaseous fluid is mixed with the gaseous fluid formed from the protective gas flow 20 and the central gas flow 19 in the plasma generation element 8, wherein the temperature and / or the position of a plasma torch is optionally adjusted or regulated with the further gaseous fluid.

[0104] To regulate and / or control the device 1 or the apparatus 6, in particular the volume flows of the gaseous fluids, it can be provided according to embodiment variants that the temperature of the induction coil 10 and / or a temperature increase of the cooling liquid flowing through the cooling channel 23 of the induction coil 10 and / or a temperature change of the wall of the plasma generation element 8 in the region of the hot gas outlet or plasma outlet from the plasma generation element 8 is measured. Based on this measured value, for example, the volume flow of the central gas stream 20 can be changed in the event of a temperature change. The temperature can be measured using known methods. For example, at least one thermocouple can be arranged in or on the wall of the plasma generation element 8 in the region of the plasma gas outlet.

[0105] It is further possible that a temperature of the protective gas flow 20 is measured and, based on this measured value, the volume flow of the protective gas flow 20 is changed in the event of a temperature change and / or that a gas pressure in the plasma generation element 8 is regulated by changing the volume flow in the exhaust gas line 41 from a treatment chamber 5.

[0106] Furthermore, it is possible that the temperature of the central gas flow 19 is calculated, and based on this calculated value, at least one volume flow of the supplied gases, in particular the volume flow of the central gas flow 19, is changed in the event of a temperature change. For this purpose, the calculation can be carried out using the formula T ca ic x cp ca ic x XVi = S(Vi XTi x cp + Pinduction. Here, T ca ic is the calculated temperature, cp caic is the calculated specific heat capacity of the hot fluid, EVi is the sum of the volume flows, S(Vi x Ti x cp is the sum of the products of the respective volume flow times the temperature of the respective volume flow x the specific heat capacity of the respective volume flow and P induction is the inductively introduced power. The volume flows refer to the protective gas flow 20, the central gas flow 19 and the possibly existing volume flow which is supplied via the at least one further flow channel 24. The temperature to be calculated can be obtained by appropriate transformation of the equation.

[0107] However, it is also possible to measure the temperature of the central gas stream 19, in particular to measure it non-contact, for example with a pyrometer.

[0108] Features of the following embodiments may constitute an independent invention, either individually or in combination with features of the preceding embodiments. In particular, for the following embodiments of the device 6 or the apparatus 1, the division of the gaseous fluid into the central gas stream 19 and a protective gas stream 20 is not mandatory.

[0109] One of these independent inventions is the device 6 for providing a plasma, comprising at least one plasma generation element 8 with at least one inlet 46 and one outlet 47 for a gaseous fluid, wherein the first flow channel 11 is arranged or formed in the plasma generation element 8, and optionally the second flow channel 12 is arranged concentrically thereto and surrounds the first flow channel 11 at least in sections, wherein the first flow channel 11 is connected to a first connection 16 for a gaseous fluid for forming a heated gas flow or a plasma flow s. The at least one inlet 46 is formed by the connection 16 for the gaseous fluid. Since a plurality of gaseous fluids can be introduced into the plasma generation element 8, as explained above and this is also the preferred embodiment of the device 6 orof the plasma generation element 8, the plasma generation element 8 can also have a plurality of inlets 46 through which the further gaseous fluids can be introduced into the plasma generation element 8. Reference is made to the above explanations.

[0110] In this embodiment, the conveying element 34 for the gaseous fluid, or several conveying elements 34 for gaseous fluids, are also present or arranged. The conveying element 34 is or are fluidly connected to the inlet 46 of the plasma generation element 8.

[0111] In the following, only one conveyor element 34 will be discussed in more detail. If multiple conveyor elements 34 are present, some or all of them may be of the same design, so that the following explanations can also be applied to these conveyor elements 34.

[0112] The conveying element 34 can accelerate the gaseous fluid conveyed by it or is thereby accelerated.

[0113] According to embodiment variants, the plasma generation element 8 can be fluidly connected to the gas supply device 31, which can preferably also have the fresh gas supply 32 and / or a recirculating gas supply 33 for a recirculating gas. The above statements regarding these embodiment variants can be applied.

[0114] According to one embodiment, the conveying element 34 can be arranged in a recirculating gas duct for the recirculating gas, which is fluidically connected to the outlet 47 of the plasma generation element 8. In the embodiment of the device 1 according to Fig. 1, the outlet of the plasma generation element 8 is not directly fluidically connected to the conveying element 34, but at least the treatment chamber 5 is arranged therebetween. Both embodiments—i.e., the direct fluid connection of the outlet 47 to the conveying element 34 and the indirect fluid connection of the outlet 47 to the conveying element 34—are possible, with the latter embodiment being the preferred one.

[0115] According to a preferred embodiment of the device 6, the conveying element 34 can be a jet pump 48, as shown by way of example in Fig. 8.

[0116] The jet pump 48 has a first gas connection 49 and a propellant connection 50, as well as an outlet 51. The first gas connection 49 can be connected to the fresh gas supply 32 or preferably to the recycle gas supply (see Fig. 1), so that fresh gas or recycle gas, which originates in particular from the exhaust gas of the treatment chamber 5, can be accelerated.

[0117] A propellant, particularly a gaseous one, is supplied to the propellant port 50 under excess pressure. This excess pressure is converted into velocity in the jet pump 48 through a cross-sectional constriction 52 through which the propellant must pass. This creates a negative pressure in the first gas port 49, which entrains and accelerates the gas supplied there.

[0118] In principle, any suitable propellant can be used, with gaseous propellants being preferred. However, in the preferred embodiment of the device 6, a fresh gas is used as the propellant, which is also supplied to the plasma generation element 8, so that the propellant connection 50 in this embodiment is connected to the fresh gas supply, for example, via the gas supply of the device 31, as shown in Fig. 1.

[0119] According to one embodiment, the volume flow of the recirculating gas stream can be regulated by the volume flow of fresh gas supplied to the jet pump 48. This can be done, for example, via a control element 52 arranged in the fresh gas supply to the jet pump, as can also be seen in Fig. 1. The control element 52 can be, for example, a flap, a slide valve, or a valve.

[0120] In general, it should be noted that the device 1 or the apparatus 6 can have a regulating and / or control device 53, to which the corresponding data from the measuring sensors of the device 1 or apparatus 6 can be provided wirelessly or by wire and which can output the corresponding regulating and / or control signals, for example for changing the volume flows of the process gases.

[0121] Alternatively or in addition to the control element 52, a controllable jet pump 48 can also be used to change or regulate the volumetric flows. The controllable jet pump 48 can be designed to regulate the volumetric or mass flow of fresh gas supplied to the jet pump 48 as a propellant.

[0122] Fig. 9 schematically shows a further and possibly independent embodiment of the device 6 for providing a plasma, wherein the same reference numerals or component designations are used for the same parts as in Figs. 1 to 8. To avoid unnecessary repetition, reference is made to the above description.

[0123] In this embodiment, the inlet 46 of the plasma generation element 8 is fluidly connected to a further fresh gas supply 32.

[0124] According to a further embodiment variant, a heat exchanger 54 is arranged in front of the conveying element 34 in the flow direction of the gaseous fluid, in particular the circulating gas.

[0125] Furthermore, according to a variant of the device 6, a further heat exchanger 55 can be arranged in the further fresh gas supply 32.

[0126] The heat exchanger 54 and the further heat exchanger 55 can be designed according to the state of the art.

[0127] It is also possible for the additional heat exchanger 55 to be fluidly connected to the heat exchanger 54 upstream of the conveying element 34. This allows the recirculating gas to be cooled in the heat exchanger 54, and the thermal energy thus obtained can be transferred to the fresh gas, which is then fed to the plasma generation element 8 via the additional fresh gas supply 32. Alternatively, the heat exchanger 54 in the recirculating gas supply 33 can also be connected to the heat exchanger 37 of the device 1 (see Fig. 1) for the transfer of thermal energy.

[0128] By cooling the circulating gas before the conveying element 34, it is also possible, in particular, to use conveying elements 34 which are less thermally resilient, such as, for example, a fan or a turbine according to an embodiment variant of the device 6.

[0129] Other usable conveying elements 34 are a pump, a vacuum pump, a compressor, an injector, etc.

[0130] According to one embodiment, at least one filter element can be arranged upstream of the conveying element 34 in the flow direction in order to be able to supply a purer gas to the conveying element 34. This can, for example, reduce or prevent abrasive loads or blockages of the conveying element 34 and the plasma generation element 8.

[0131] Features of the following embodiments may constitute an independent invention, either individually or in combination with features of the preceding embodiments. In particular, for the following embodiments of the device 1, the division of the gaseous fluid into the central gas stream 19 and the protective gas stream 20 and / or the use of a conveying element 34 is not mandatory.

[0132] Figures 10 and 11 schematically show further and possibly independent embodiments of the device 1, wherein the same reference numerals or component designations are used for the same parts as in Figures 1 to 9. To avoid unnecessary repetition, reference is made to the above description.

[0133] The device 1 for the thermal treatment of the substance 2 in these embodiments again comprises the treatment chamber 5 and at least one device 6 for providing a plasma, wherein the treatment chamber 5 has an inlet 56 and an outlet 57 for the supply and discharge of a gaseous fluid into and out of the treatment chamber 5. In both embodiments, it is provided that the outlet 57 of the treatment chamber 5 is connected to at least one heat exchanger 58 flow s, wherein the heat exchanger 58 has an inlet 59 and an outlet 60 for the supply and discharge of the gaseous fluid.

[0134] The gaseous fluid is preferably the exhaust gas from the treatment chamber 5, which is circulated through the device 1.

[0135] The heat exchanger 58 has at least one heat storage element 61. The heat storage element 61 can be formed, for example, from a material based on or containing aluminum oxide (Al2O3), silicon dioxide (SiCF), iron(III) oxide (Fe2O3), titanium dioxide (TiCF), potassium oxide (K2O), calcium oxide (CaO), sodium oxide (Na2O), etc.

[0136] The at least one heat storage element 61 serves to absorb heat from the gaseous fluid that is passed through the heat exchanger 58 and to store it for later use.

[0137] In the embodiment according to Fig. 10, at least one further heat exchanger 58 is provided, which also has at least one heat storage element 61. However, it is possible for only one heat exchanger 58 with at least one heat storage element 61 to be present. In this case, the thermal energy extracted from the process gas and stored in the heat storage element 61 can be used, for example, for another process. It can also be provided that the thermal energy extracted from the process gas during cooling is used as heating energy for space heating and / or water heating and / or for power generation. For this embodiment, it can be provided that the at least one heat exchanger 58 is arranged in a fluid circuit which connects the outlet 57 of the treatment chamber 5 to the inlet of the treatment chamber 56.

[0138] In the preferred embodiment, the process gas, i.e. in this case the recycle gas, is reused in the process itself.

[0139] In the embodiment variant of device 1, this is achieved by using at least two heat exchangers 58, each with at least one heat storage element 61. For this purpose, the hot recycle gas is passed from the outlet 57 into the first heat exchanger 58. In the illustration in Fig. 10, this is the upper of the two heat exchangers 58. In this first heat exchanger 58, the recycle gas is cooled, and the extracted thermal energy is stored in its heat storage element 61.

[0140] After the first heat exchanger 58, the cooled recycle gas is fed into a gas conveying element 62, such as a fan or one of the aforementioned conveying elements 34. For this purpose, the outlet 60 of the first heat exchanger 58 can be fluidly connected to the gas conveying element 62. The gas conveying element 62 can build up the pressure to guide the recycle gas through the heat exchangers 68 or within the circuit.

[0141] If the recycle gas is still too hot to be introduced into the gas delivery element 62, according to one embodiment of the device 1, it is possible for the recycle gas to be mixed with a cooler fresh gas upstream of the gas delivery element 62. The fresh gas can, for example, be injected into the cooled recycle gas. The fresh gas can, for example, be supplied via the gas supply device 31. In this embodiment, a supply element for supplying a cooling medium, such as the fresh gas, into the gaseous fluid can be arranged upstream of the gas delivery element 62 in the device 1 in the flow direction of the gaseous fluid.

[0142] In general, (pre-)cooling of the recycle gas can also take place at a different location. It is also possible for a partial flow of the recycle gas to be diverted and, if necessary, fed to a separate cooling system using a different heat exchanger to avoid thermal overload of the heat storage elements 61. Provision can be made for the separately cooled partial gas flow to be fed to the heat exchanger 58, i.e., to the at least one heat storage element 61, which is not heated but is (thermally) discharged.

[0143] According to another embodiment, alternatively or additionally, it can be provided that a cooler fresh gas is introduced into the hot recycle gas stream before the inlet 59 or at the inlet 59, for which purpose a fresh gas supply can be arranged at the inlet 59 or before the inlet 59 of the heat exchanger 58 for the gaseous fluid.

[0144] The gas conveying element 62 can also be arranged at a different location in the device 1. After the first heat exchanger 58, the cooled recycle gas, preferably with the gas conveying element 61, flows via the inlet 59 into the second (lower) heat exchanger 58. For this purpose, the inlet 59 of the second heat exchanger 58 is connected to the outlet 60 of the first heat exchanger 58 directly or indirectly via the gas conveying element 61.

[0145] At least one heat storage element 61 of the second heat exchanger 58 is already heated during normal operation, i.e., not during the start-up phase of the device 1, so that the recirculating gas is reheated in this second heat exchanger 58. In the process, the heat storage element 61 of the second heat exchanger 58 cools down.

[0146] The heated recycle gas is fed back as process gas via the outlet 60 of the second heat exchanger 58, which is fluidly connected to the inlet 56 of the treatment chamber via the plasma generation element 8. Beforehand, it is heated to the desired process temperature in the plasma generation element 8.

[0147] This process continues until the first heat exchanger 58 reaches a critical temperature. This can be predefined, for example, by the temperature resistance of the gas conveying element 62.

[0148] At this point, the flow direction of the recycle gas is reversed. For this purpose, corresponding cycle valves 63 or other suitable elements for changing the flow direction of the gas can change their position accordingly, so that the exhaust gas from the treatment chamber 5 is subsequently first passed through the second (lower) heat exchanger 58 for cooling and then through the first (upper) heat exchanger 58 for reheating. In other words, in this cycle, the second heat exchanger 58 becomes the first heat exchanger 58 and the first heat exchanger 58 becomes the second heat exchanger 58. This cycle then continues until the critical temperature is reached again and the cycle valves 63 change their position again.

[0149] The corresponding wiring diagram for this cycling can be seen in Fig. 10.

[0150] The change in the position of the cycle flaps 63 or the aforementioned elements preferably occurs fully automatically. For this purpose, a temperature sensor can be arranged in each of the heat exchangers 58, which provide corresponding measurement signals. According to another embodiment of the device 1 shown in Fig. 11, the heat exchanger 58 can have several heat storage elements 61 that are rotatably arranged so that the heat storage elements 61 can be alternately supplied with the gaseous fluid, in particular the hot exhaust gas or the recycle gas, from the treatment chamber 5.

[0151] The hot gas or hot exhaust gas (circulation gas) can be fed through the upper part of the heat exchanger 58. It transfers its heat to the heat storage elements 61, i.e., the respective heat storage element 61 positioned in the correct rotational position. The cooled exhaust gas (circulation gas) is then fed back to the plasma generation element 8 as process gas. The thermal energy reaches the likewise stationary lower part of the heat exchanger 58 via the heat storage elements 61, where it can heat the supplied cold fresh air. This heats up, and the heat storage elements 61 cool down again, making them available for recharging.

[0152] This process can be controlled by a temperature sensor, e.g., a thermocouple, in the cold exhaust gas. The amount of heat stored per heat storage element 61 can be specified by the speed of the heat exchanger 58.

[0153] The heated fresh gas can then be fed to the plasma generation element 8.

[0154] In the illustration in Fig. 11, eight heat storage elements 61 are provided. However, fewer or more than eight heat storage elements 61 can also be used, for example, three or four or five or six or seven or nine or ten, or significantly more than eight, such as more than 100, etc.

[0155] The heat storage elements 61 can be designed as honeycomb bodies, as sphere beds or generally as bedded material, as foam, as bodies manufactured by an additive process, etc. The permissible pressure loss, the space requirement, etc., can be specified via the shape.

[0156] The heat storage elements 61 can be provided with a coating, for example a catalytic coating.

[0157] Since the heat or thermal energy is preferably used again in the same process, it can also be provided in these embodiment variants that the at least one heat exchanger 58 is arranged in a fluid circuit which connects the outlet 57 of the treatment chamber 5 with the inlet 56 of the treatment chamber 5.

[0158] According to a further embodiment of the device, a third heat exchanger 64 can be arranged upstream of the gas conveying element 62 in the flow direction to further cool the gaseous fluid after it leaves the first heat exchanger 58. This third heat exchanger 64 can be designed without heat storage elements 61.

[0159] In the above explanations, it was assumed that, apart from the partial volume flow that is completely removed from the process via the discharge element 44, the remaining volume flow is completely cooled. However, it is also possible that only a portion of the remaining volume flow is cooled. In this case, this portion can be used, for example, to cool components in the plasma generation element 8.

[0160] The examples show possible design variants, whereby combinations of the individual design variants are also possible.

[0161] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size.

[0162] Reference symbol list

[0163] Facility 30 jetty

[0164] Substance 31 Gas supply device

[0165] Recording 32 fresh gas supply

[0166] Housing 33 Recirculating gas supply

[0167] Treatment chamber 34 Conveyor element

[0168] Device 35 connection

[0169] Hot gas stream 36 Ignition gas

[0170] Plasma generation element 37 heat exchanger

[0171] Element body 38 coating

[0172] Induction coil 39 strips

[0173] Flow channel 40 distance

[0174] Flow channel 41 exhaust pipe

[0175] Distance 42 flap

[0176] Surface 43 Cross-sectional tapering element

[0177] Distance 44 discharge element

[0178] Connection 45 feed device

[0179] Port 46 Input

[0180] Supply line 47 output

[0181] Central gas flow 48 jet pump

[0182] Shielding gas flow 49 Gas connection

[0183] Output 50 propellant connection

[0184] Duct element 51 outlet

[0185] Cooling channel 52 control element

[0186] Flow channel 53 control device

[0187] Connection 54 heat exchanger

[0188] Angle 55 heat exchanger

[0189] Cooling gas flow 56 inlet

[0190] Longitudinal center axis 57 exit

[0191] Outlet opening 58 Heat exchanger inlet outlet Heat storage element Gas conveying element Cycle flap Heat exchanger

Claims

Patent claims 1. Device (6) for providing a plasma, comprising at least one plasma generation element (8) with an inlet (46) and an outlet (47) for a gaseous fluid, wherein a first flow channel (11) is arranged in the plasma generation element (8), optionally a second flow channel (12) arranged concentrically thereto, which surrounds the first flow channel (11) at least in sections, wherein the first flow channel (11) is connected to a first connection (16) for a gaseous fluid for forming a heated gas flow and / or a plasma flow s, characterized in that the inlet (46) of the plasma generation element (8) is fluidly connected to a conveying element (34) with which the gaseous fluid can be accelerated.

2. Device (6) according to claim 1, characterized in that the plasma generating element (8) is fluidly connected to a gas supply device (31).

3. Device (6) according to claim 2, characterized in that the gas supply device (31) has a fresh gas supply (32) and / or a recycle gas supply (33) for a recycle gas.

4. Device (6) according to claim 3, characterized in that the conveying element (34) is arranged in a circulating gas guide for the circulating gas, which is fluidly connected to the outlet (47) of the plasma generating element (8).

5. Device (6) according to one of claims 1 to 4, characterized in that the conveying element (34) is a jet pump (48).

6. Device (6) according to claim 5, characterized in that the jet pump (48) has a propellant connection (50) which is connected to the fresh gas supply (32).

7. Device (6) according to claim 6, characterized in that the jet pump (48) is a controllable jet pump (48) with a control of the volume or quantity flow of fresh gas.

8. Device (6) according to one of claims 1 to 7, characterized in that the inlet (46) of the plasma generating element (8) is connected to a further fresh gas supply (32) flow s.

9. Device (6) according to one of claims 1 to 8, characterized in that a heat exchanger (54) is arranged in front of the conveying element (34) in the flow direction of the gaseous fluid.

10. Device (6) according to claim 9, characterized in that a further heat exchanger (55) is arranged in the further fresh gas supply (32).

11. Device (6) according to claim 10, characterized in that the further heat exchanger (55) is fluidly connected to the heat exchanger (54) upstream of the conveying element (34).

12. Device (6) according to one of claims 1 to 3 and 8 to 11, characterized in that the conveying element (34) is a fan or a turbine.

13. Device (1) for the thermal treatment of a substance (2), in particular a solid, comprising at least one device (6) for providing a plasma, characterized in that the device (6) for providing a plasma is formed according to one of claims 1 to 12.

14. A method for operating a device (6) for providing a plasma for generating a hot gas stream and / or a plasma stream for thermally treating a material (2), comprising the steps: - supplying a gaseous fluid into a plasma generating element (8) of the device (6), - generating a plasma in the plasma generating element (8); - Providing a hot fluid flow through the plasma, optionally by heating the gaseous fluid with the plasma to produce a hot gas, wherein the hot fluid flow is directed outside the plasma generation element (8) onto the material (2) to be treated, characterized in that the gaseous fluid is accelerated before being fed into the plasma generation element (8).

15. The method according to claim 14, characterized in that another gaseous fluid is added to the gaseous fluid.

16. Method according to claim 15, characterized in that the temperature and / or the angle of a plasma torch is adjusted or regulated with the further gaseous fluid.

17. Method according to one of claims 14 to 16, characterized in that the plasma is generated inductively with at least one electrical induction coil (10), and that furthermore the temperature of the induction coil (10) and / or a temperature increase of a cooling liquid for the induction coil (10) and / or a temperature change of the wall of the plasma generation element (8) in the region of the hot gas outlet is measured and on the basis of this measured value the volume flow of the gaseous fluid and / or further gaseous fluid is changed in the event of a temperature change.

18. Method according to one of claims 14 to 17, characterized in that it further comprises the steps - supplying a fresh gas stream to a gas supply device (31) of the plasma generating element (8), - Supplying a circulating gas stream from a treatment chamber (5), in which the material (2) is thermally treated, to the gas supply device (31), wherein a jet pump (48) is used for supplying the circulating gas stream, which is operated with a fresh gas stream as propellant gas.

19. Method according to one of claims 14 to 18, characterized in that the volume flow of the recycle gas flow is regulated with the volume flow of fresh gas supplied to the jet pump (48).

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