Induction system for gas heating

Abstract

The present invention relates to an induction gas heating device, aimed at improving the thermal and environmental efficiency of gas heating in industrial applications. The device according to the invention uses a set of induction coils arranged around one or more pipes. These pipes, which can adopt a spiral configuration in order to maximise heat exchange, are designed to allow the efficient transition of cold gas at the inlet to hot gas at the outlet.

Description

Description Title of the invention: INDUCTION SYSTEM FOR HEATING GAS

[0001] CONTEXT

[0002] Industrial heating systems play a key role in many industrial processes, providing the necessary heat either to facilitate a specific process or by acting as a reactor. Traditionally, these systems rely on the use of selected fuels to generate the required heat. However, this combustion method has major environmental drawbacks, mainly due to the carbon dioxide emissions it generates. In this context, the electrification of industrial heating systems has become a preferred alternative, aiming to replace conventional combustion methods.

[0003] Electrification solutions for these installations include the use of electric resistances and plasma torches. However, electric resistances struggle to produce temperatures exceeding 1200°C and suffer from a lack of efficiency. On the other hand, although plasma torches are capable of reaching high temperatures and are efficient, they require considerable maintenance and present reliability issues for long-term operations (ranging from several weeks to months without interruption).

[0004] Faced with these challenges, it is clear that there is a need for a solution capable of heating gases efficiently, while overcoming the shortcomings mentioned above.

[0005] SUMMARY OF THE INVENTION

[0006] The present invention relates to an induction gas heating device designed to optimize thermal efficiency while avoiding the emission of pollutants and harmful substances.

[0007] It describes a heating device using magnetic induction, equipped with several induction coils arranged close to a conduit. These induction coils generate variations in the magnetic field which induce the heating of said conduit. The conduit thus heated then transmits its calories to the gas circulating in said conduit, thus making it possible to heat the transported gas. Thus, the invention makes it possible to efficiently obtain very high temperatures for the gas transported in the conduit.

[0008] In a particularly clever manner, the invention combines an electrically conductive insert heated by induction and a conduit, for example a spiral conduit, so that the insert is no longer simply a flow-disrupting element, but a real heat source internal to said conduit. In other words, the insert housed in the conduit becomes an active heating element for the gas circulating in the conduit, making it possible to inject calories in a localized and direct manner into the heart of the gas flow. In addition, the insert thus introduced into the conduit generates turbulence on the initial gas flow and increases the exchange surface, thus improving mixing and heat transfer to the gas. This dual functionality fundamentally modifies the thermal dynamics of the device according to the invention, producing a technical effect that was unpredictable and not previously implemented.

[0009] The invention also provides an induction heating device operating in a closed circuit, where the gas emanating from the outlet of the gas circuit is reinjected into the heating device to be heated again.

[0010] This invention finds various applications in the industrial sector, where the heated gases can be directed towards industrial furnaces or radiant ducts, or used directly. The invention thus makes it easier to obtain very high temperatures, for example above 2000°C, which are sometimes difficult to obtain in certain industrial sectors.

[0011] The invention also provides an induction heating device operating in a closed circuit, where the residual heat emanating from industrial furnaces or radiant ducts is recovered using a heat recovery unit.

[0012] In addition, this induction heating device can be adapted to the process of thermal pyrolysis of hydrocarbons, cracking or steam cracking of hydrocarbons into gaseous hydrogen and granular carbon, by heating the hydrocarbons in a conduit until reaching the temperature necessary for their dissociation.

[0013] The features of any of the disclosed embodiments may be used in combination with each other, without limitation. Furthermore, other features and advantages of the present disclosure will become apparent to those skilled in the art in light of the following detailed description and the accompanying drawings.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Embodiments of the invention relate to the induction heating device for heating gas.

[0016] This invention is illustrated in the accompanying drawings, in which like reference letters / numbers indicate corresponding parts in the several figures. Embodiments and advantages of the invention will be apparent from the following description, when read with reference to the accompanying drawings, in which:

[0017] FIG. 1 is a schematic diagram of an induction heating device, according to the first embodiment of the present invention.

[0018] FIG. 2: a) is a diagram of a spiral duct of the induction heating device, according to the first embodiment of the present invention, b) is a detailed view of a spiral duct of the induction heating device, according to the first embodiment of the present invention.

[0019] FIG. 3: a) and b) show diagrams of variants of a spiral conduit of the induction heating device, according to the first embodiment of the present invention.

[0020] FIG. 4 is a diagram of an induction heating unit for an induction heating device, according to the second embodiment of the present invention.

[0021] FIGS. 5 and 6 schematically represent an induction heating device, according to the first and second embodiments of the present invention.

[0022] FIG 7: a) and b) represent a diagram of a practical application of the induction heating device according to the first embodiment of the present invention to a pyrolysis process.

[0023] FIG. 8 shows the arrangement of the turns according to the ratio described in the present application.

[0024] FIG. 9 illustrates a graph showing the performance of the device according to the invention.

[0025] DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention relates to an induction heating device for heating gases that can be introduced into industrial furnaces and / or radiant tubes, or that can be used directly for a heating, drying or cooking process of a product. The invention is characterized by the use of magnetic induction to generate heat, offering a clean and efficient alternative to traditional heating methods.

[0027] The induction heating device comprises a plurality of induction coils arranged around an electrically conductive conduit or a conduit comprising an electrically conductive insert, said conduit (and / or insert(s)) being heated by eddy currents which are created inside the conduit (and / or insert(s)) under the effect of a fast alternating magnetic field penetrating said conduit (and / or insert(s)) when the alternating current passes through the induction coils. This process then allows rapid and uniform heating of the gas flowing through the conduit thus heated by induction.

[0028] According to a first aspect of the invention, the invention relates to an induction gas heating device (500), the system comprising:

[0029] An induction heating unit (150) comprising a set of induction coils (50) configured to generate a magnetic field when an electric current passes through them, and at least one conduit (100) of which at least a part - called magnetic portion - is located in the magnetic field generated by the induction coils (50), said magnetic portion being formed by an electrically conductive material.

[0030] Said conduit(s) (100) having a cold gas supply inlet (110) and a hot gas outlet (120).

[0031] The induction coil (50) is electrically connected to an electrical energy source or a power supply to provide the alternating electric current. To operate, the induction coil (50) is traversed by an alternating electric current in order to generate eddy currents by magnetic induction in the magnetic portion of the conduit. The electrical energy source is of the type of an alternating electric source, or the power supply is configured to electrically connect the induction coils (50) to an alternating electric network.

[0032] According to one embodiment of the invention, the magnetic portion of the conduit extends in a spiral in the magnetic field created by the induction coils (50). The spiral configuration is specifically chosen to maximize the contact surface with the gas, improving the efficiency of heat transfer between the magnetic portion and the gas flowing in the conduit. This configuration is also advantageous for optimizing space within the heating unit.

[0033] According to one embodiment of the invention, the spiral of the magnetic portion of the conduit comprises several turns arranged according to the following ratio:

[0034] [Math 1] [ L 0035] J 0 < (2.7TD) < 30

[0036] And preferably, for a compact layout:

[0037] [Math 2] [ L 0038] J 0 < < 1 (2.7TD)

[0039] Where (see Fig. 8): - d is the distance measured along the shortest distance separating two turns consecutive, and corresponds to a direction of elongation of the spiral, taken locally at the level of the two turns considered; - D is the maximum transverse distance between the ends of a coil.

[0040] According to certain embodiments, d is between 0 and 2000 mm, preferably 0 and 200 mm, more preferably 0 and 50 mm.

[0041] According to certain embodiments, D is between 10 and 3000 mm and preferably 300 and 1000 mm. The value of D will depend on the compactness of the system and the characteristic length of the conduit (100) (diameter, edge, width, etc.).

[0042] In one embodiment, the conduit may have a circular, square, rectangular, or other geometric cross-section, thereby providing flexibility in design to accommodate different applications and performance requirements.

[0043] According to one embodiment, the induction heating unit comprises at least two conduits, preferably configured in a spiral, superimposed laterally or longitudinally. When the conduits are arranged in a spiral, it is understood that the turns of the first conduit are nested, that is to say intertwined with the turns of the second conduit. When the two conduits are stacked, it is understood that they are leaning against each other so as to extend against each other, in a sandwich configuration for example. In the context of the invention, the stacking can be done axially with respect to the spiral shape of the conduits, that is to say in the direction of extension of the spiral, or the stacking can be done radially with respect to the spiral shape of the conduits, that is to say in a direction perpendicular to the direction of extension of the spiral.This modularity allows easy adaptation of the system to specific needs in terms of heating capacity and available space.

[0044] According to one embodiment, said conduit(s) (100) comprises several cold supply inlets and / or several hot gas outlets. In the case where the device comprises a single conduit, then the conduit comprises a single cold supply inlet or several cold supply inlets all connected to the same duct. Similarly, when the device has a single duct, then the duct has a single hot gas outlet or several hot gas outlets all connected to the same duct. On the other hand, when the device has several ducts, then each duct has a specific cold supply inlet or the ducts are all connected to the same cold supply inlet. Similarly, when the device has several ducts, then each duct has a specific hot gas outlet or the ducts are all connected to the same hot gas outlet.

[0045] In one embodiment, at least one insert, such as a uniform / non-uniform twisted ribbon or a twisted ribbon with an alternating axis, for creating a turbulent flow of the gas in the conduit and increasing the exchange surface area, may be placed inside the conduit to improve gas mixing and increase heating efficiency.

[0046] Said conduit(s) and / or insert(s) may be selected from the list consisting of steel, preferably magnetic, stainless steel (preferably for oxidizing gases), copper, aluminum, nickel, titanium, nickel-based alloys, conductive ceramics, graphite, cobalt-based alloys, tungsten, and mixtures thereof. More generally, the conduit(s) and / or insert(s) are chosen from electrically conductive materials, and preferably also metallic. Thus, when the at least one insert is formed from an electrically conductive material, it actively participates in the generation of heat by induction, producing eddy currents under the effect of the magnetic field generated by the induction coils of the induction heating unit.

[0047] The said conduit(s) and / or insert(s) can be selected according to two criteria: the nature of the gas to be heated and the temperature ranges at which the gas is heated. For example, to heat CH4 or N2 to temperatures above 2000°C, graphite or tungsten can be used.

[0048] According to another aspect, the hot gas outlet (120) of the device according to the invention is connected to at least one industrial furnace (10) and / or at least one radiant tube (20).

[0049] According to another aspect, the device according to the invention comprises at least one heat recovery unit (300) placed between, on the one hand, the industrial furnace(s) (10) and / or the radiant tube(s) (20) and, on the other hand, the cold gas supply inlet (110) of the conduit (100).

[0050] The induction heating device may be a closed-circuit heating device in which a heat recovery unit is in closed-circuit communication with the induction heating unit to extract waste heat.

[0051] The heated gases from the induction heater can be used for various industrial applications such as: industrial furnaces, direct heating of the product, pyrolysis, cracking or steam cracking of hydrocarbons, furnace heating / reheating for steel slabs or long products, annealing furnace for steel / glass / cement, heating a gas and circulating it in a radiant tube to heat a product, heating H2 or syngas and injecting it into a DRI or blast furnace, drying of raw materials / food industry and chemical reactors to produce syngas or hydrogen by dry reforming or steam reforming.

[0052] The induction gas heater can be used to heat a variety of gases, depending on the specific needs of industrial processes. A non-exhaustive list of gases that can be heated includes: hydrogen, nitrogen, oxygen, argon, carbon dioxide, carbon monoxide, methane, ethane, propane, butane, ammonia, natural gas, syngas, water vapor, and air.

[0053] According to other embodiments, which can be taken in isolation from each other or in combination with each other:

[0054] - the at least one conduit is electrically conductive or the at least one conduit is electrically insulating;

[0055] - the at least one insert (200B) may be electrically conductive or insulating. If conductive, it preferably comprises an electrically conductive and / or magnetic surface coating, such as for example of the type comprising an alloy ferromagnetic, a conductive ceramic, or a graphite-based composite material. This advantageous configuration makes it possible to locally increase the magnetic field and improve the efficiency of heat transfer to the gas flowing in the at least one conduit (100), in the immediate vicinity of the at least one insert (200B). In other words, such a surface coating makes it possible to interact more effectively with the magnetic field generated by the induction coils (50) of the induction heating unit, and to allow more efficient induction heating of the gas flow flowing in the at least one conduit (100). If the insert is insulating, a coating as described above is essential, particularly when the conduit itself has insulating characteristics.

[0056] - the surface coating extends over all or part of the at least one insert (200B). This advantageous configuration makes it possible to concentrate the magnetic field generated by the induction coils (50) of the induction heating unit in specific areas inside the at least one conduit (100), at the at least one insert (200B), thus optimizing the heating of the gas. In addition, the surface coating chosen for the at least one insert (200B) can be chosen to withstand high temperatures and corrosive environments, thus improving the service life of the at least one insert (200B) and reducing maintenance costs.

[0057] - according to a first embodiment variant, the at least one insert (200B) is mounted statically in the at least one conduit (100). In other words, the at least one insert (200B) is mounted immobile and fixed in the at least one corresponding conduit (100). This advantageous configuration is simpler and more economical to implement.

[0058] - according to a second embodiment, the at least one insert (200B) is mounted in a movable manner in the at least one conduit (100). In particular, according to a first example, the at least one insert (200B) is mounted in a rotatable manner in the at least one conduit (100). The rotation of the at least one insert (200B) makes it possible both to homogeneously heat the at least one insert (200B) and to create turbulence and swirling flows of the gas circulating in the at least one conduit (100), thus promoting heat exchanges with the at least one conduit (100). at least one insert (200B). According to a second example, complementary or alternative to the first example, the at least one insert (200B) is mounted so as to move in translation in the at least one conduit (100), and in particular driven by a back and forth movement in said at least one conduit (100). The back and forth movement of the at least one insert (200B) makes it possible to create uniform distribution of the heat in the at least one insert (200B) and in the gas circulating in the at least one conduit (100), avoiding stagnation of said gas. In a particularly advantageous manner, the at least one insert (200B) is mounted both rotatably and slidably in the at least one conduit (100). This advantageous configuration makes it possible to reduce cold spots in the at least one conduit (100), limits fouling of the surfaces and improves heat transfer.Indeed, in applications where the gas can deposit residues, such as, for example, during the pyrolysis of hydrocarbons, the movement of the at least one insert (200B) makes it possible to limit the accumulation of these deposits on the surface of the at least one conduit (100) and / or the at least one associated insert (200B).

[0059] - the device comprises a magnetic screen located around the induction coils, opposite the at least one conduit (100) in which the at least one insert (200B) is inserted. This advantageous configuration makes it possible in particular to prevent the dispersion of the magnetic field towards the outside, and to force the field lines to penetrate into the at least one conduit (100) in order to heat the at least one insert (200B). The material chosen to form such a screen is more particularly chosen from those of the type of a soft magnetic material with high magnetic permeability, such as pure iron, ductile cast iron, permalloy, silicon steel, soft magnetic ferrite.

[0060] - the device comprises an insulating conduit (100) housing the induction coils.

[0061] - by way of non-limiting example, the at least one insert (200B) is manufactured by 3D metal printing or by machining. The at least one insert (200B) has a geometry optimized to generate turbulence in the flow of gas circulating in the at least one conduit (100), and to maximize the heat transfer to said gas.

[0062] - the device may comprise one or more temperature and / or pressure and / or flow rate sensors associated with the at least one conduit (100), as well as a control module - for example controlled by an artificial intelligence module - the control module being connected and configured to dynamically adjust the intensity and / or the frequency of the induction current flowing in the induction coils. Alternatively or additionally, the control module is configured to adjust the gas flow rate and / or the speed of movement of the at least one insert (200B) as a function of the data measured by at least some of said sensors. Preferably, the control of the device is carried out according to a real-time process.

[0063] - the insert comprises at least one part - called magnetic portion - located in the magnetic field generated by the induction coils, and, preferably, the conduit does not comprise a magnetic portion.

[0064] FIG. 1 illustrates an induction heating unit (150) for heating gas. Said induction heating unit (150) comprises an induction coil (50) and a spiral conduit (100) in which an insert (200B) is housed. The conduit (100) and / or the insert (200B) may comprise at least one part - called magnetic portion - located in the magnetic field generated by the induction coils (50). More particularly, the spiral conduit (100) extends in a winding forming several turns around an axis of elongation (X). In the example illustrated in FIG. 1, the turns of the spiral conduit (100) are placed against each other, relative to the axis of elongation (X). Optionally, the turns may be spaced apart from each other, relative to the axis of elongation (X). The spiral duct (100) is configured to have a cold gas supply inlet (110) and a hot gas supply outlet (120).The induction coil (50) may be arranged around at least a portion of the spiral duct (100) - forming the magnetic portion - relative to the elongation axis (X), so as to heat said magnetic portion and then, by conduction and radiation, the gases circulating in the spiral duct (100) supplying for example an industrial furnace (10) / a radiant tube (20). The induction coil (50) is provided with an energy source or a power supply (not shown) for providing an electric current. alternative to the induction coil (50), necessary for the formation of the magnetic field and eddy currents in the magnetic portion of the spiral duct (100) and / or the insert (200B). The hot gas supply outlet (120) of the duct may be in fluid communication with an industrial furnace (10) / radiant tube (20) for heating the product therein. The industrial furnace (10) / radiant tube (20) may be a standard heating device / heating tube commonly used in industry. The cold gas supply inlet may be located at the magnetic portion of the spiral duct (110), or located beyond said magnetic portion, relative to the elongation axis (X). Similarly, the hot gas supply outlet (120) may be located at the magnetic portion of the spiral duct (100), or located beyond said magnetic portion, relative to the elongation axis (X).

[0065] FIGS. 2 and 3 illustrate the different possible embodiments of the spiral duct (100) of the first embodiment of the present invention. Said spiral duct (100) can have a circular, square, rectangular or other geometric cross-section. The characteristic dimension (diameter, edge, length, ...) and the number of turns of the spiral duct can be chosen according to the volume of the gas to be heated.

[0066] According to another embodiment of the invention, the spiral duct (100) in which an insert (200B) is housed, can heat several gases, said spiral duct (100) being able to be a combination of one or more spiral duct units (100), each being able to comprise an insert (200B), leaning against each other following or perpendicular to it (see figures 3a and 3b). Said spiral duct (100) can comprise several cold gas inlets and several hot gas outlets superimposed laterally or longitudinally.

[0067] FIG. 4 illustrates an induction heating unit (250) according to another embodiment of the invention. The induction heating unit (250) comprises a conduit (200A) and an insert (200B), preferably in the form of a twisted tape (known as "twisted tape"). The insert (200B) is placed inside the conduit (200A) and the induction coil (50) is arranged around and / or close to at least a portion of the length of the conduit (200A) - called magnetic portion - so as to heat the conduit (200A) and the gases flowing in said conduit (200A) before their introduction into the industrial furnace (10) and / or the radiant tube (20). The conduit (200A) and the insert (200B) may form a single integral unit by welding said conduits at their respective ends. The insert (200B) may be connected to the conduit (200A) by any known fastening method, namely connecting pins, threaded fittings, screws etc. within the scope of the invention, without this limiting the scope of the invention.

[0068] At least one insert (200B) may be in the form of twisted tape or twisted tape with alternate axis. At least one insert (200B) may be with a uniform or non-uniform pattern. Twisted tapes are flat pieces or strips that are twisted to obtain a regular or non-regular pattern providing improved heat transfer in the system for a relatively low increase in pressure drop in laminar, transient and turbulent flow regimes. Twisted tape geometries divide the flow within the duct, creating vortex flow paths and promote mixing. An increase in the surface area of ​​the insert leads to improved heat exchange efficiency and increased compactness of the system.

[0069] The compactness and dimensions of the heating unit are determined based on a dimensionless parameter "R". This represents the ratio between the internal surface area of ​​the duct (100 / 200A) and the sum of the areas of all the faces covering the insert (or inserts) (200B) in the magnetic portion. When calculating the dimensionless number (R), it is important to emphasize that the duct and the insert (or inserts) all have an equal length in this magnetic portion. R is preferably less than 20 for systems that produce high temperatures with a short magnetic portion length and for which pressure drop is not a problematic parameter. This R value range is preferably used when the space occupied by the induction heating unit is limited and / or preferably to place the installation close or very close to the furnace / radiant tube.R is preferably between 20 and 40 for systems that produce high temperatures with an average magnetic portion length or length (no space or space problem). occupied by the induction heating unit) and whose pressure drop can be a moderately or highly problematic parameter.

[0070] Accordingly, in some embodiments, the insert(s) (200B) is arranged according to a ratio R representing the ratio between the internal surface area of ​​the conduit in the magnetic portion (100 / 200A) and the sum of the areas of all the faces covering the insert(s) (200B) in this specific portion. When calculating R, the conduit(s) (100 / 200A) and the insert(s) (200B) have an equal length in the magnetic portion.

[0071] Preferably, the ratio is:

[0072] [Math 3] R < 40 And more preferably of:

[0073] [Math 4] R < 20

[0074] According to another embodiment, the insert is configured to have a plurality of blades mounted on a central axis or placed independently in the conduit (100 / 200A) joining them to the ends of the respective conduits.

[0075] The cold gas is supplied through a cold gas inlet (210) into the induction heating unit (250) and the hot gas exits through a hot gas outlet (220) of said induction heating unit (250). The cold gas then flows through the conduit (200A) and around said twisted ribbon (200B) which is adapted to increase the travel time of the gas through the magnetic portion to improve heat transfer with the conduit (200A) and more efficiently heat the gas.

[0076] When the conduit (200A) comprises one (or more) insert(s) (200B), said conduit (200A) and / or the insert (200B) may be formed from an electrically conductive material, at least a part of which - called the magnetic portion - is located in the magnetic field generated by the induction coils (50). in other words, either the conduit (200A) or the insert (200B), or both, may produce heat under the action of the magnetic field when the device is in operation.

[0077] There are therefore at least three different embodiments:

[0078] According to a first embodiment, when the conduit (200A) comprises one (or more) insert(s) (200B), the conduit (200A) comprises a magnetic portion but the insert does not.

[0079] According to a second embodiment, when the conduit (200A) comprises one (or more) insert(s) (200B), the conduit (200A) and the insert (200B) comprise a magnetic portion.

[0080] According to a third embodiment, when the conduit (200A) comprises one (or more) insert(s) (200B), the insert (200B) comprises a magnetic portion but the conduit (200A) does not. This embodiment is very energy efficient and is simple to produce.

[0081] Electrically conductive materials, such as for example a metallic material type, and in particular including high temperature magnetic steel and / or a suitable material with similar properties will be chosen according to the set temperature range. For temperatures below 1200°C, steels, in particular magnetic steels, will be considered. For temperatures above 1200°C, other materials, such as graphite or tungsten, may be used.

[0082] According to an embodiment of which at least one part - called magnetic portion - is located in the magnetic field generated by the induction coils (50), said magnetic portion being formed by an electrically conductive material,

[0083] FIG. 5 illustrates the induction heating device (500) for heating gases. The induction heating system (500) comprises an induction heating unit (150), an industrial furnace (10) and / or a radiant tube (20) and a heat recovery unit (300), for heating gases according to the first embodiment of the present invention. The hot gas supply outlet (120) of the spiral conduit (100) is in fluid communication with the industrial oven (10) and / or radiant tube (20) for heating the product therein. The industrial oven (10) and / or radiant tube (20) is a standard heating duct and / or heating device commonly used in industry.

[0084] FIG. 6 illustrates an induction heating device (1000) for heating gas is presented. The induction heating device (1000) comprises an induction heating unit (250), an industrial furnace (10) and / or a radiant tube (20) and a heat recovery unit (300), for heating gas according to the second embodiment of the present invention.

[0085] The hot gas outlet (220) of the induction heating unit (250) is in fluid communication with the industrial furnace (10) and / or radiant tube (20) for heating the product therein. The industrial furnace (10) and / or radiant tube (20) is a standard heating conduit and / or heating device commonly used in industry.

[0086] By way of non-limiting example, the induction heating device (500, 1000) is equipped with a closed-loop heat extraction system, allowing the reuse of heat from the hot gases emanating from the industrial furnace (10) and / or the radiant tube (20). A heat recovery unit (300) is connected between the industrial furnace (10) and / or the radiant tube (20) and the inlet of the induction heating unit (110, 210). This closed-loop system significantly contributes to the reduction of electricity consumption.

[0087] The role of the heat recovery unit (300) is to recover hot gases / fumes in a radiant furnace / tube and circulate them between the radiant furnace / tube and the inlet of the induction heating unit (110, 210). It is composed of at least:

[0088] - A hot gas / fume collection and circulation system: the radiant furnace / tube is connected to a hot gas / fume extraction system (e.g., extraction hoods, fan, compressor, etc.) to extract the hot gas / fume and circulate it to another component of the heat recovery unit (300) or to the inlet of the induction heating unit (110, 210). The collection systems are designed to maximize the capture rate while minimizing the entry of cold air into the system.

[0089] - Collection ducts: The captured hot gases / fumes are directed through ducts to another component of the heat recovery unit (300) or to the inlet of the induction heating unit (110, 210).

[0090] - Hot gas / flue gas treatment system: For furnaces, hot gas / flue gas may pass through scrubbers and filters to remove specific gas components and / or to remove solid particles, sulfur oxides (SOx), nitrogen oxides (NOx), and other pollutants. This device may not be of critical importance for radiant tubes, given the lack of direct interaction between the heated gas and the product.

[0091] - Heat exchangers: The hot gases / flue gases can pass through heat exchangers either to recover residual heat or to lower the temperature of the hot gases / flue gases, if necessary, to avoid damaging the equipment (extraction system, collection ducts, etc.) with excessively high temperatures. The recovered energy can be used to preheat the gas to be heated by the induction heating unit before injecting it into the inlet (110, 210). The recovered energy can also be used for other processes requiring heat.

[0092] - Gas control and analysis systems: Advanced control systems regulate the flow of flue gases and hot gases through the recovery process to optimize heat recovery efficiency and ensure compliance with environmental standards. Gas analyzers continuously measure gas composition to adjust the various processes.

[0093] - Gas mixing station: This type of system allows the composition of the gases to be heated to be adjusted if necessary.

[0094] - Ventilation system: A small portion of the gases may be vented through a chimney. Before release, it may be cooled if necessary to comply with discharge temperature regulations.

[0095] FIGS. 7a-7b illustrate a scenario of a possible application of the present invention in which hydrogen gas is extracted from hydrocarbons by pyrolysis of methane. During extraction, the hydrocarbon feedstock (e.g., methane) is introduced into the spiral conduit (100) by a inlet (110) of the induction heating unit (150). The hydrocarbon feedstock is then heated by the magnetic portion itself heated by induction by the induction coil (50) as well as by the insert (200B) present in the spiral conduit (100). If the spiral conduit (100) is insulating, the hydrocarbon feedstock will be heated only by the insert (200B). The heated hydrocarbon feedstock is then directed into the conduit (350) at point (A). When the hydrocarbon feedstock is directed through the spiral conduit (100) of the induction heating unit (150), at a temperature equal to or greater than the cracking temperature of the hydrocarbon feedstock (e.g., methane), the hydrocarbon feedstock at least partially pyrolyzes the feedstock to form hydrogen gas and carbon.The hydrogen gas is thus collected at point (B) of the conduit (350) and the granular carbon flows towards the end of the conduit (350), from where it can be recovered. The cracking reaction followed in the said system is described below.

[0096] CH4 -> C + 2H2

[0097] In the induction heating device according to the invention, the at least one insert, made of an electrically conductive material, such as for example magnetic steel or graphite, is advantageously coated with a surface treatment forming a catalytic layer, such as for example Ni / Al2O3 for the reforming of methane, Pt / C for the oxidation of CO. In this case, the at least one insert makes it possible to configure the device according to the invention as an integrated chemical reactor, combining both a heating function and a catalysis function for in situ reactions. More generally, in the device according to the invention, the at least one electrically conductive insert comprises a functionalized surface treatment making it possible to react with the gas circulating in the at least one conduit, according to a catalysis function predetermined by a chemical compound doping the surface treatment of the at least one insert.

[0098] In addition, such a device can be combined with different renewable energy sources or different heat recovery systems.

[0099] The present invention has the technical advantages mentioned below and further provides technical progress compared to the prior techniques mentioned above:

[0100] The temperature can be regulated by controlling one or more gas compositions entering the heating device (inductive).

[0101] This system offers the ability to achieve precise and uniform gas temperatures while completely eliminating combustion and its associated drawbacks. Most combustion heating systems have uneven hot gas (or flue) temperatures throughout the combustion zone. These can vary due to various factors, such as uneven fuel and oxygen distribution, flame turbulence, the presence of contaminants, pressure, etc. As a result, the generated gas / flue temperatures are heterogeneous and hot spots are created. Hot spots resulting from combustion lead to problems such as equipment degradation, premature wear, and even safety risks. All these problems will be avoided with this innovation.

[0102] The nature of the gas and its temperature, heated by the induction heating unit (150, 250) and injected into an industrial furnace, can be chosen in advance by the person skilled in the art and adapted according to the nature / composition of the product to be heated. This provides total and precise control of the environment in the furnace / radiant tube, thus improving the quality of the products, reducing material losses (e.g. by oxidation) caused by chemical reactions linked to combustion and the production of undesirable gases. In addition, this guarantees production stability and ensures process safety by avoiding the production of toxic and dangerous gases.

[0103] This system allows the reduction of CO2 emissions and pollutants such as nitrogen oxides NOx and sulfur oxides SOx.

[0104] This system facilitates the electrification of radiant furnaces / tubes to achieve carbon neutrality, without requiring major and costly modifications to existing installations. Current combustion burners can be substituted by the output of the induction heating unit (120, 220) without cause changes in the structure of the furnace, thus eliminating the need to use expensive combustion burners.

[0105] This system facilitates the electrification of radiant ovens / tubes without modifying the heating cycles of the radiant ovens / tubes and the products.

[0106] The outlet of the induction heating unit (120, 220) connected to the furnace can take several shapes (circular, square, rectangular, hood, ...) unlike the case with the burners. This allows to control the circulation and the hydrodynamics of the flows of the gas heated by the induction heating unit (150, 250) in the furnace and / or on the product. The homogeneous dispersion of the hot gas in the furnace helps to reduce the time required for thermal stabilization, thus leading to an increase in the production rate.

[0107] The gas heated by the induction heating unit (150, 250) can be produced in a constant and continuous manner.

[0108] The gas heated by the induction heating unit (150, 250) may be introduced into the furnace, the radiant tube and / or onto the product, all under controlled pressure and flow rate. This represents an additional contributor to the production capacity. For example, the gas heated by the induction heating unit (150, 250) may be projected onto a product with high pressure. This promotes an acceleration of the product heating process, thus reducing the time required to reach the desired temperature and increasing the production rate.

[0109] Closed loop to optimize energy consumption.

[0110] The induction heating unit (150, 250) is both compact and adaptable. A single unit can be used to power multiple zones of a furnace, and / or a radiant tube, and / or multiple radiant tubes. Similarly, each zone of a furnace and / or radiant tube has the ability to incorporate one or more induction heating units.

[0111] Efficient and controlled production of hydrogen and solid carbon.

[0112] The foregoing description of specific embodiments of the invention will so fully reveal the general nature of the embodiments herein that others, applying present knowledge, may readily modify and / or adapt for various applications these specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be understood within the meaning and scope of the equivalents of the disclosed embodiments.

[0113] The effectiveness of the present invention has been demonstrated by numerical simulations and validated by reference correlations (Manglik et al., 1993), by comparing the following three devices under identical gas flow conditions:

[0114] - case A: induction heating of the duct wall, without insert in the duct;

[0115] - case B: induction heating of the duct wall, with unheated insulating insert in the duct;

[0116] - case C: induction heating of the internal insert (twisted ribbon type) replacing heating of the duct wall.

[0117] The comparative results are shown in Figure 9, which represents the temperature of the gas heated by one and the other of the above devices, as a function of the length of the conduit considered.

[0118] More particularly, the results show that curve C exhibits a significantly higher temperature rise compared to curve A, demonstrating the effectiveness of the device according to the invention. Indeed, using the same electrical power and under identical conditions of use of the conduit (i.e. the same gas, the same flow rate and identical geometric configurations), the device according to the invention, incorporating a heated insert in the conduit, makes it possible to raise the temperature of the gas from 172°C to 687°C, i.e. an increase of more than 200%, compared to a similar device without an insert in the conduit. It should be noted that the exclusive heating of the external wall of a conduit, even associated with an unheated insert generating turbulence, as visible on curve B, proves insufficient to obtain a rapid temperature rise of the gas over a reasonable distance.By opting for an electrically conductive insert, the invention induces localized heating by the generation of currents. induction in the insert subjected to the magnetic field, thus promoting direct heat input to the gas circulating in the conduit.

[0119] Furthermore, assuming that the gas flow rate circulating in the duct is doubled, the device according to the invention maintains a significant advantage over a similar device not comprising a heated insert in the duct. These results demonstrate that the technical effect proposed by the invention, and observed by experimentation, does not result from a simple coincidence linked to a particular set of parameters, but rather from a robust and reproducible phenomenon, produced by the clever addition of an electrically conductive insert in the duct, making it possible both to disturb the gas flow to promote heat exchanges along the heating portion of the duct, but also to improve heat transfers to said gas by promoting internal heating in the duct by establishing eddy currents in the insert.

[0120] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Accordingly, although the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein may be practiced with modification within the spirit and scope of the embodiments as described herein. 11

Claims

Claims

1. An induction gas heating device (500), characterized in that the system comprises: - an induction heating unit (150) comprising a set of induction coils (50) configured to generate a magnetic field when an electric current passes through them, and - at least one conduit (100) of which at least one part - called magnetic portion - is located in the magnetic field generated by the induction coils (50), said magnetic portion being formed by an electrically conductive material, - Said conduit(s) (100) having a cold gas supply inlet (110) and a hot gas outlet (120), characterized in that the induction gas heating device (500) comprises at least one electrically conductive insert housed in the at least one conduit and configured to create a turbulent flow of gas in said at least one conduit.

2. Device according to claim 1, in which the at least one electrically conductive insert comprises an electrically conductive and / or magnetic surface coating, such as for example of the type comprising a ferromagnetic alloy, a conductive ceramic, or a graphite-based composite material.

3. Device according to the preceding claim, in which the surface coating extends over all or part of the at least one insert.

4. Device according to any one of claims 1 to 3, wherein the at least one insert is statically mounted in the at least one conduit.

5. A device according to any one of claims 1 to 3, wherein the at least one insert is rotatably mounted in the at least one conduit.

6. Device according to any one of claims 1 to 3, in which the at least one insert is mounted so as to be movable in translation. in the at least one conduit, and in particular animated by a back and forth movement in said at least one conduit.

7. A device according to any preceding claim, wherein the device comprises a magnetic shield located around the induction coils, opposite the at least one conduit into which the at least one insert is inserted.

8. A device according to any preceding claim, wherein the device comprises an insulating conduit housing the induction coils.

9. Device according to any one of the preceding claims, in which the at least one electrically conductive insert comprises a functionalized surface treatment making it possible to react with the gas circulating in the at least one conduit, according to a catalysis function predetermined by a chemical compound doping the surface treatment of the at least one insert.

10. Device according to any one of the preceding claims, in which the insert (200B) comprises at least one part - called magnetic portion - located in the magnetic field generated by the induction coils (50), and preferably the conduit (100 / 200A) does not comprise a magnetic portion.

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