Method and system for operating and / or decarbonising a more particularly industrial production process

Abstract

The present invention relates to a method for operating and / or decarbonising a more particularly industrial production process, preferably a coating process, such as a galvanising, in which a heated melt is provided and / or kept available, wherein the melt is heated selectively by means of at least one electric heating device and / or at least one non-electric heating device, and wherein if there is excess power in a power grid, at least some of it is taken from the power grid and used to operate the electric heating device.

Description

[0001] Method and system for operating and / or decarbonising a particularly industrial production process

[0002] The invention relates to a method and a system for operating and / or decarbonizing a particularly industrial production process, preferably a coating process such as galvanizing, in which a heated melt is provided and / or stored. Furthermore, the invention also relates to uses of the system in question in heat-consuming processes, preferably in coating processes such as galvanizing.

[0003] The present invention relates to the field of operating industrial processes in which the manufacturing, processing, and / or treatment of physical goods or products takes place on a commercial scale. An "industrial process" within the meaning of the present invention is therefore understood to mean the mass production and / or mass manufacture or commercial processing of physical goods or components, in particular for coating workpieces.

[0004] Industrial production processes inevitably require high process heat, especially during heat treatment or process steps intended to alter material properties and / or composition. Due to the commercial scale of the production processes in question, it is inherently necessary that the required heat or energy supply be ensured continuously and / or throughout the entire production process, and thus permanently.

[0005] In this context, the present invention specifically targets heat-consuming production processes that utilize a heated melt or in which a heated melt is provided and / or stored. Heated melts are preferably understood to mean liquid metal of any type and alloy, which is used in a variety of ways in industrial production processes, for example, in the casting or coating of workpieces. However, the primary starting point of the invention is coating processes in which a firmly adhering layer of amorphous material is applied to the surface of a workpiece. For this purpose, a heated melt acting as a coating compound is then stored or provided accordingly.

[0006] A coating process that is particularly frequently used in industry is galvanizing, especially hot-dip galvanizing, where a metallic, molten zinc coating is applied to protect against rust or corrosion by immersing the workpieces to be coated in the zinc-containing coating mass.

[0007] Especially in galvanizing, it is crucial that the zinc melt stored or provided for coating is maintained at a defined process temperature permanently or with a constant heat supply. This is the only way to ensure targeted process control, given the interdependence between the desired coating quality on the one hand and the temperature of the melt or coating mass on the other.

[0008] The process heat requirement in production processes of the type mentioned above, especially in coating processes or galvanizing, is in practice covered by the combustion of fossil fuels, mostly gas, such as natural gas. In practice, the heating of a galvanizing furnace with the coating or galvanizing mass inside is carried out using natural gas-fired gas burners.

[0009] However, the use of natural gas in industrial processes is problematic due to the associated emission of climate-damaging emissions, such as carbon dioxide. In addition to the associated lack of sustainability and climate impact, a number of geopolitical aspects also speak against the use of natural gas as an energy source, especially in industrial processes. The above disadvantages are particularly significant in the industrial processes in question that use a melt, since the continuous heating or heating of the melt to a comparatively high process temperature requires a particularly high energy demand and ultimately high consumption of the fossil fuels or natural gas required for this purpose.

[0010] Despite the disadvantages outlined above, the implementation of natural gas to generate process heat in industrial production processes essentially meets the complex requirements for continuous and defined heating of melts, as the combustion of natural gas, which usually occurs via a large number of gas burners, generally ensures sufficient heat input and thus reliable heating of the melt. For this reason, and in view of the high costs associated with any modifications to the plant technology, the practice has so far refrained from replacing natural gas as an energy source in coating processes, particularly in galvanizing.

[0011] The object of the present invention is to avoid the aforementioned disadvantages of the prior art or at least to substantially reduce them.

[0012] To achieve the aforementioned object, the invention proposes a method and a system for operating and / or decarbonizing an industrial production process, wherein the melt is heated optionally by means of at least one electric heating device and / or at least one non-electric heating device. This means that the heating can be operated solely electrically, solely non-electrically, or in a hybrid combination—both electrically and non-electrically.

[0013] In developing the present invention, it was recognized that there are a number of advantages associated with no longer heating the melt exclusively with a non-electrical or gas-based energy source, but rather with the optional use of an electric heating device. Heating the melt using the electric heat storage can supplement the non-electrical heating device or completely replace the non-electrical or gas-based heating device. In this respect, the term "optional" ultimately encompasses three different process configurations or modes to provide the entire required power for the industrial process or for heating the melt. Thus, according to the process, heating the melt can be carried out exclusively using the non-electrical heating device (first process mode).Furthermore, the process allows for heat input through a combined heat input using the non-electrical heating device and the electric heating device (second process mode). Finally, the process also allows for heating the melt exclusively using the electric heating device (third process mode).

[0014] Due to the optional use of the electric heating system, the disadvantages associated with non-electric or gas-based heating systems are avoided or mitigated, particularly with regard to the avoidance of climate-damaging emissions such as carbon dioxide. This creates the basis for the decarbonization envisaged by the process, since the replacement of an electric heating system according to the invention allows the heat input required for heating the melt to be achieved with a significant reduction, and in some cases, complete elimination, of climate-damaging emissions such as carbon dioxide.

[0015] In this respect, the term "decarbonization," as used in the context of the present invention, is to be understood as the avoidance or at least reduction of climate-damaging emissions such as those generated in conventional industrial processes, in particular during the combustion of fossil fuels such as natural gas. The term "climate-damaging emissions" is to be understood broadly and ultimately includes all gaseous emissions that have a negative impact on the climate. The present invention is primarily aimed at the avoidance or reduction of carbon dioxide (CO2), but is not limited to this. Thus, other gases, for example carbon monoxide, methane, nitrous oxide, or other climate-effective greenhouse gases (GHG), can also be climate-damaging emissions within the meaning of the teaching of the invention. In other words, the invention proposes a hybrid heating concept, wherein for the permanent heating of the melt, optionally oran electric heating system is used at least partially, in line with the desired decarbonisation of the industrial process to be operated.

[0016] A "permanent" provision or holding of the melt is preferably understood to mean a period of at least one hour, preferably at least five hours, in particular at least ten hours. Depending on the scope of the process, this may also include one day, 24 hours, or even several days. In this respect, the term "permanent" should preferably be understood broadly.

[0017] Particularly with reference to a coating process or galvanizing, the term “permanent” defines the period of use during which a melt collected in a vessel can be used in a stationary and / or functional manner to coat workpieces without draining or processing as part of a coating process.

[0018] In addition, the term "melt", as preferably used in the context of the present invention, is to be understood as a preferably non-ferrous, metallic coating mass provided and / or held in a vessel or other receiving means, which is used stationary or as an immersion bath with an at least essentially constant volume or mass over the entire process time, i.e. without draining from the vessel. In this respect, a melt in the sense of the present invention is preferably not to be understood as foundry melt for casting or primary shaping corresponding foundry products. Nevertheless, the use of the method according to the invention can also be expedient in foundry processes and is therefore expressly covered by the teaching of the invention.

[0019] In order to create the invention with the described hybrid heating strategy in an industrial process, a number of technical prejudices had to be overcome. For example, depending on the application or in a targeted manner, industrial processes have so far used either burners that are heated with natural gas or other fossil gaseous energy sources. Alternatively, heat-consuming processes that use electricity exclusively, either inductively or resistance-heated, are known. Due to the complex process control in heat-consuming processes, hybrid use using a combination of electrical and non-electrical energy sources has not yet been considered. In particular, it has also been considered disadvantageous and disproportionate to provide hybrid systems in other technical fields, since changing energy sources orThe associated energy input involves complex conversion and switching measures and a corresponding interruption of the heat supply. This interruption can last for several minutes to hours, accompanied by corresponding interruptions in production and technical precautions to prevent a drop in the process temperature. As a result, the use of hybrid systems or parallel operation of electrical and non-electrical heating in heat-consuming processes has not been considered in practice to date.

[0020] In contrast to this prevailing opinion, it has now been recognized within the scope of the inventive solution that a hybrid heating system consisting of an electrical heating device and a non-electrical heating device is very suitable for use in industrial production processes, specifically for heating a melt that is held or provided in particular for a coating process.

[0021] Within the scope of the inventive solution, it was determined that continuously heated melts, preferably metal melts and / or non-ferrous melts, in particular zinc-containing metal melts, are suitable for hybrid heat supply because they have a comparatively high thermal inertia and / or their temperature changes only relatively slowly upon heat supply and / or heat removal due to a relatively high mass and heat capacity. This results in a comparatively large time window and / or reduced sensitivity for implementing the process modes described above, the selection of a heating device, or the switching from one heating device to another, and the hybrid heating system.As a result, within the scope of the present invention, it is proposed for the first time and in the form of a self-contained concept to implement, in order to decarbonize a heat-consuming process, the heating of a melt used therein not exclusively by means of a gas-based or non-electrical heating, but at least partially or optionally also by means of an electrical heating device, whereby parallel or simultaneous heating can also be carried out by means of the non-electrical and electrical heating device.

[0022] Due to the inertia of the melt, the optional heating by means of the electric heating device and / or the non-electrical heating device provided for in the process ensures that, even in the event of a brief interruption of the heat input into the melt to be heated, there are no process-related losses to be feared compared to the non-electrical or gas-based heating known from the prior art.

[0023] In a targeted addition to the hybrid heating described above, the invention also provides that, in order to operate the electrical heating device, surplus electricity generated in a power grid, in particular in the public power grid, is at least partially extracted and used to operate the electrical heating device.

[0024] In this context, surplus electricity is electrical power that is only available at fluctuating output over time and can therefore lead to an oversupply of electricity or overcapacity in the power grid. As a result, situations are increasingly occurring in which electrical energy or electricity cannot be fully consumed due to the excess supply in the power grid.

[0025] Surplus electricity, i.e. electrical energy with temporally fluctuating output, is due in particular to the share of renewable energies, whose electricity share is increasingly and prioritized being fed into the power grid. Since the underlying energy sources, namely sun, wind, and water, are not constantly available over time and their availability is also difficult to predict, fluctuating output and overcapacities or periods of surplus electricity are ultimately unavoidable. For example, a short-term high wind speed can lead to an oversupply of electricity or power peaks in the power grid, with the associated problem that the resulting surplus electricity must be diverted or consumed to avoid overloading the power grid and the associated damage.

[0026] The term "power grid," as used in the context of the present invention, is preferably to be understood broadly and, in electrical power engineering, refers to a network for the transmission and distribution of electrical energy. It consists of electrical lines such as overhead lines and underground cables, as well as the associated facilities such as switching and transformer stations. Large, spatially adjacent, and electrically connected power grids are referred to as interconnected grids, while small, spatially separated power grids are referred to as isolated grids. The method according to the invention is particularly preferably applied in power grids that obtain their electrical energy at least partially from renewable energies.

[0027] In the near future, the feeding of the proportionally increasing renewable energies from sun, wind and water into the power grid will therefore increasingly lead to power peaks and / or surplus power, which can only be partially absorbed by electricity consumers and will therefore be offered as so-called surplus power on the electricity market well below its production costs or at prices which, in relation to its energy content, are lower than for a fossil fuel with the same calorific value, or for free, i.e. without any consideration, or even at negative prices.

[0028] To date, overload current has not been used to reduce power peaks in connection with metal smelting. Instead, attempts have been made to store surplus power or power peaks in storage systems such as batteries and pumped storage power plants and later feed it back into the grid. However, the use of battery systems is problematic in terms of costs and the associated resource requirements. Especially from an ecological point of view, the use of batteries that have a limited lifespan and decrease in performance over time or with increasing use is counterproductive and therefore not effective from a sustainability point of view. The recycling and disposal of batteries on the required scale is also known to be problematic. This also applies to the buffers and storage systems in question.Storage systems require a high level of effort to set up such systems, which, depending on the geographical conditions and the high losses associated with energy conversion, do not represent a practical solution.

[0029] In this respect, no satisfactory concept for the effective use of surplus electricity has yet been developed in practice. At the same time, however, the management of surplus electricity is an important aspect of the energy transition, as the surplus electricity in question is largely generated from renewable energies.

[0030] The invention now creates the possibility of using the electrical energy from surplus electricity specifically to operate an electrical heating device or to heat a melt.

[0031] This requirement is based on the above-mentioned finding that heating the melt using an electrical heating device on an industrial scale in combination with a non-electrical heating device is actually possible in a targeted manner.

[0032] Against this background, the solution according to the invention also makes a contribution to avoiding overloading of the power grid and to the efficient use of surplus electricity, which primarily comes from renewable energy sources, i.e. solar, wind and hydropower.

[0033] As a result, the solution according to the invention provides a specifically coordinated concept, purposefully combining two findings that are already advantageous in terms of decarbonization and / or the avoidance of climate-damaging emissions, such as carbon dioxide. Decarbonization is thus already achieved essentially through the use of the electric heating system. This basic idea is then completed or supplemented by the further requirement that surplus electricity is deliberately used to operate the electric heating system. This surplus electricity comes primarily from renewable energy sources, so that the surplus electricity itself also originates from an emission-free source. In this way, an emission-free process chain can be realized while completely avoiding the formation of climate-damaging emissions, such as carbon oxides.

[0034] In this respect, the solution according to the invention proposes a contribution to the decarbonization of an industrial production process using a melt, while at the same time providing for the integration of surplus electricity or electricity generated from renewable energies and thus also addressing aspects of grid serviceability or relieving the load on the electricity grid.

[0035] Having considered the above fundamental considerations of the inventive solution, advantageous procedural aspects of the present invention are discussed below.

[0036] The occurrence of excess current can be detected in the power grid via a detection device. This can preferably be done automatically, in particular frequency- and / or internet-controlled. A detection device is also understood to be a receiving device for a signal or the like that the grid operator issues manually or automatically and that is received by the receiving device. After the excess current is detected, the electrical heating device and the non-electrical heating device are controlled by a control and / or regulating device.Accordingly, within the scope of the method for operating the production process, a distinction is made between a time period before the occurrence of the excess current and a time period after the occurrence of the excess current, wherein after the occurrence of the excess current, the electrical and the non-electrical heating device are preferably regulated / controlled, wherein the excess current is used to operate the electrical heating device. The use of the excess current is preferably such that the heated melt is provided and / or maintained in a defined process temperature range, in particular permanently or over the entire production cycle. The use of the excess current to operate the electrical heating and the shutdown of the non-electrical heating as required is preferably such that the production process is carried out continuously while the electrical heating is used.Accordingly, the use of excess electricity to operate the electric heating device is not associated with any impairment compared to conventional non-electric or gas-based heating, so that the use of hybrid heating using the electric heating device does not lead to any restrictions on the production process, which continues continuously during the changeover from one process mode to another.

[0037] With regard to a specific process control, it can preferably be provided that upon occurrence and / or detection of the excess current, the heating power of the non-electrical heating device is reduced and the operation of the electric heating device is started, preferably wherein the operation of the non-electrical heating device is terminated and the heating of the melt is carried out exclusively by the electric heating device using excess current.

[0038] This type of process is particularly advantageous when surplus electricity is expected to be available for a longer period of time. For this purpose, the process can explicitly stipulate that the production process is carried out continuously using only electrical heating or, in this case, using the surplus electricity. The non-electrical heating system can then be permanently deactivated, which leads to maximum decarbonization and / or avoidance of the formation of climate-damaging emissions such as carbon oxides, since the use of fossil fuels is completely eliminated. Of course, it cannot be ruled out that, starting from purely electrical heating, the non-electrical heating system could be switched on again. A complete shutdown of the electrical heating system or, in this case, the surplus electricity could also be implemented.Exclusive heating of the non-electrical heating device is possible. This always occurs when and when it is foreseeable that the excess power will no longer be available. The reduction or shutdown of the non-electrical heating device and / or the startup or activation of the electric heating device can occur continuously or discontinuously. Preferably, the shutdown or startup is automatically coordinated such that the reduction of the non-electrical heating device is compensated by a corresponding startup of the electric heating device and the total heat energy introduced into the melt and / or the process temperature is maintained at least essentially constant throughout the entire production process. This avoids undesirable fluctuations in the processing temperature of the melt.This is ultimately made possible by controlling / regulating the temperature of the melt, which is measured continuously.

[0039] In this context, a transition period can be defined, the beginning of which is defined as the detection of excess current and / or the beginning of the shutdown of the non-electrical heating device and / or the beginning of the startup of the electric heating device. The end of the transition period is defined by the complete shutdown of the non-electrical heating device and / or the complete startup of the electric heating device.

[0040] The transition time in question is preferably freely selectable, although due to the comparatively high heat capacity of the melt, flexibly adjustable transition times are in principle possible. However, these also depend on the total volume of the melt bath.

[0041] For example, a transition time in the range of a few seconds, for example a maximum of 45 or a maximum of 30 seconds, up to several minutes, for example from 5 to 10 minutes, preferably 5 to 30 minutes, can be provided, during which the non-electrical heating device is completely shut down and the electric heating device is completely started up. However, shorter or longer transition times are also possible, particularly depending on the available excess current and the amount of melt bath. The heating of the melt before the occurrence and / or detection of the excess current can preferably take place exclusively by the non-electrical heating device, and the electric heating device can be switched on in addition to the non-electrical heating device when the excess current is occurred and / or detected. In this respect, it is preferably provided that the switching on or offThe activation of the electrical heating device is specifically linked to the occurrence of excess power, whereby during times when there is no excess power in the power grid, heating is provided exclusively by the non-electrical heating device. However, it is understood that the electrical heating device can also be operated without excess power, for example, by directly connecting it to any electrical power source that is preferably at least partially, in particular entirely, powered by renewable energy sources.

[0042] With regard to the operation of the non-electrical heating device, according to a preferred method, it is provided that the non-electrical heating device is operated with a CCh-free or at least natural gas and / or CO2-reduced fuel gas, in particular pure hydrogen or a hydrogen-containing fuel gas, for example a fuel gas in the form of a natural gas-hydrogen mixture.

[0043] According to this particularly preferred process, decarbonization is achieved not only through the use of an electric heating system, but also through a modification of the non-electric heating system, whereby hydrogen is used or mixed in instead of pure fossil fuel gas or natural gas. The combustion products of hydrogen are primarily water vapor, which is beneficial in preventing the formation of climate-damaging emissions, such as carbon oxides, which are produced during the combustion of natural gas.

[0044] Preferably, as long as pure hydrogen is not yet available on a large-scale, commercial scale, it is particularly expedient if the hydrogen is admixed with a carrier gas, preferably natural gas, to obtain the hydrogen-containing fuel gas. The carrier gas or natural gas in question is preferably at least partially a process gas arising in an industrial process, such as mine gas and / or coke oven gas. The hydrogen content in the mixed gas, in particular consisting of or containing natural gas and hydrogen, is preferably at least 20%, preferably at least 40%, particularly preferably at least 60%, most preferably at least 80% or 90%.

[0045] In particular, a hydrogen-containing fuel gas is used to operate the non-electrical heating devices, wherein the fuel gas contains at least 1 to 100 vol.%, preferably 25 to 100 vol.%, particularly preferably 50 to 100 vol.%, of hydrogen.

[0046] Particularly preferably, the non-electrical heating device is operated exclusively and / or 100% with hydrogen, preferably pure and / or green hydrogen.

[0047] In particular, so-called green hydrogen is used exclusively to operate the non-electrical heating system and / or as pure fuel gas or partially in a mixed gas, for example, with natural gas. Green hydrogen is produced by electrolysis of water, with the electricity required for this being generated from renewable energy sources.

[0048] This makes it possible according to the invention to also operate the non-electrical heating device at least partially from renewable energies, namely from hydrogen obtained from renewable energy sources.

[0049] The preferred process control described above with regard to the use of hydrogen, preferably green hydrogen, improves the decarbonization of the process according to the invention and further optimizes the sustainability of the process according to the invention, in particular in addition to the hybrid heating by means of electrical heating energy.

[0050] The heat input into the melt or the heating of the melt can preferably be carried out at least partially indirectly via a vessel containing the melt, preferably with a furnace chamber surrounding the vessel being heated by the electric and / or non-electric heating device. In particular, the furnace chamber is heated by the non-electric heating device, and the melt is additionally heated directly by an electric heating device, preferably arranged in the melt.

[0051] Accordingly, there is preferably a spatial separation of the non-electrical heating device on the one hand and the electric heating device on the other. In this case, the non-electrical heating device can preferably be used in the furnace chamber to heat the vessel wall, whereas the electric heating device can be accommodated in the vessel for direct contact with the melt. This prevents, in particular, the electric heating device from coming into contact with potentially harmful exhaust gases during the non-electrical heating device or the combustion of the fuel gas. However, it is also possible to arrange the non-electrical heating device and the electric heating device together in the furnace chamber. For this purpose, the preferably rod-shaped electric heating device can be provided with a protective layer in order to provide protection against the heat generated by the non-electrical orexhaust gases emitted by gas-based heating equipment.

[0052] The heating of the melt is preferably carried out in such a way that the melt is kept at a process temperature which is at least 10 °C, preferably at least 20 °C, in particular at least 30 °C, above a melting temperature of the melt.

[0053] It is preferably provided that the melt is kept at a process temperature in the range of 200 °C to 1200 °C, preferably in the range of 350 °C to 470 °C or preferably in the range of 510 °C to 610 °C.

[0054] Particularly preferably, the melt can be kept at a process temperature in the range from 400 °C to 600 °C, preferably in the range from 415 °C to 470 °C, or preferably in the range from 510 °C to 610 °C, in particular 520 °C to 600 °C. The temperature ranges in question are preferred for galvanizing processes, with the increased temperature range from 510 °C to 610 °C or 520 °C to 600 °C being provided for high-temperature galvanizing. In particular, the melt is provided and / or kept as an immersion bath, in particular a galvanizing bath, in a metallic coating or coating process, with at least one component to be coated or covered with the melt being immersed in the melt and removed from the melt.

[0055] Particularly preferably, the melt or immersion bath is provided as a molten metallic alloy. Preferably, a molten zinc alloy is provided or used as the melt.

[0056] The method according to the invention has proven to be particularly useful for hot-dip galvanizing or hot-dip galvanizing, in particular batch galvanizing, wherein a material to be coated or a component to be coated, preferably steel or a steel component, is immersed continuously (for example strip and wire) or piece by piece (for example components) at temperatures of approximately 400 °C to 600 °C in a heated vessel with liquid zinc alloy, so that it forms a resistant alloy layer of iron and zinc on the steel surface or material surface and above it a very firmly adhering zinc or zinc alloy layer.

[0057] The method according to the invention enables a continuous production process, in particular a hot-dip galvanizing process, whereby, compared to the prior art heating of the melt solely based on non-electrical or gas-based heating, no losses can be observed with regard to the temperature and / or quality of the melt to be maintained. Nevertheless, as described in detail above, the method according to the invention allows for significantly improved sustainability and grid service due to the associated decarbonization.

[0058] In connection with this, the process according to the invention makes it possible to provide and / or maintain the melt at the process temperature continuously and / or for a period of at least 1 hour, preferably at least 5 hours, particularly preferably at least 10 hours. Alternatively or additionally, the melt is also provided in a mass or dimension customary for hot-dip galvanizing or industrial galvanizing, preferably with a mass of 200 to 800 t (tons), preferably 250 to 750 t, in particular 300 to 700 t, in particular in a vessel intended for the industrial coating process or for industrial galvanizing.

[0059] It should be noted, however, that the method according to the invention is not limited to galvanizing or coating processes. Ultimately, the teaching of the invention can be applied to all coating processes known from the prior art, provided that a heated melt is used or maintained as the coating material.

[0060] In the following, according to a further aspect of the present invention, the system according to the invention for operating and / or decarbonizing an industrial process, preferably an industrial production process, is described.

[0061] Specifically, the present invention accordingly also relates to a system for operating and / or decarbonizing a preferably industrial production process using a melt, preferably a coating process such as galvanizing, wherein a vessel is provided for receiving and heating a melt. The system according to the invention comprises at least one electric heating device and at least one non-electrical heating device.

[0062] According to the invention, the system comprises at least one control and / or regulating device for selectively heating the melt by means of the electrical heating device and / or the non-electrical heating device, wherein the control and / or regulating device is additionally designed to at least partially extract excess power accumulating in a power grid and to operate the electrical heating device with the extracted excess power. In this way, the previously discussed advantages and special features of the present invention can be implemented accordingly in accordance with the device. Accordingly, the system according to the invention is designed and / or conceived in particular for the device-based implementation of the previously discussed method. The advantages previously mentioned for the method also apply equally to the system.

[0063] In a further preferred embodiment of the invention, the control and / or regulating device has a detection device for detecting the occurrence of excess current and a control and / or regulating device for operating the electrical heating device and the non-electrical heating device after the detection of the excess current. The detection device can also be designed as a receiving device for receiving signals or the like that are sent by the network operator or third parties when excess current occurs. The control and / or regulating device can comprise the detection device and the control and / or regulating device as a higher-level module. It is understood that it is fundamentally also possible to implement the detection device and the control and / or regulating device as separate modules or units.To form structural units that are interconnected by signaling. The control and / or regulating device is then to be understood abstractly or as a non-device-related, overarching designation of the structural units in question.

[0064] In a further preferred embodiment of the invention, a furnace chamber at least partially surrounding the boiler is provided, preferably wherein the electrical heating device and / or the non-electrical heating device is / are designed to heat the furnace chamber and / or is / are arranged on or in the furnace chamber, in particular wherein the non-electrical heating device is / are arranged on or in the furnace chamber and the electrical heating device for contacting the melt and / or for directly heating the melt is / are arranged in the interior of the boiler and / or the electrical heating device is / are arranged on or in the region of the outside or outer wall of the boiler.The spatial separation of the electric heating system from the non-electric heating system prevents contact with the electric heating system from combustion gases emitted by the non-electric heating system. This protects the electric heating system from harmful exhaust gases from the non-electric heating system, enabling long-term, reliable operation of the hybrid heating system.

[0065] In view of the above special features and advantages, the present invention also relates to the use of the system according to the invention for reducing and / or avoiding the formation of climate-damaging emissions, such as carbon oxides, in the generation of process heat during the operation of a heat-consuming process, preferably a coating process, such as galvanizing, in particular hot-dip galvanizing.

[0066] Accordingly, the present invention also relates to the use of the system according to the invention for removing excess current when current peaks occur and / or for increasing grid serviceability in a heat-consuming process, preferably a coating process, such as galvanizing, in particular hot-dip galvanizing.

[0067] It is understood that the system according to the invention can also be used both to reduce and / or prevent the formation of climate-damaging emissions, such as carbon dioxide, and to extract excess electricity during power peaks and / or to increase grid efficiency, i.e., a combination of the above-mentioned application aspects. As previously described, the applications in question relate to coordinated or mutually reinforcing aspects of decarbonization, since operating the electrical heating system using excess electricity initially reduces the proportion of the non-electrical heating system, while using the excess electricity, which originates primarily or exclusively from renewable energy sources, further increases decarbonization and sustainability.

[0068] Accordingly, the uses or aspects in question are preferably to be understood in their intended combination. Further features, advantages, and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings and the drawings themselves. All described and / or illustrated features, individually or in any combination, constitute the subject matter of the present invention, regardless of their summary in the claims or their reference back to them.

[0069] It shows:

[0070] Fig. 1 is a schematic representation of a system according to the invention and the sequence of the method according to the invention and

[0071] Fig. 2 is a perspective view of a melt held in a vessel to schematically illustrate the hybrid heating process in the sense of the method or system according to the invention.

[0072] Fig. 1 schematically shows a system 1 according to the invention for operating and / or decarbonizing an industrial production process using a melt 2.

[0073] In the following, the components or devices of the system 1 according to the invention are first described in order to subsequently discuss the sequence of the method according to the invention using the system 1 according to the invention.

[0074] In this context, it should be noted that the following statements with regard to the system 1 according to the invention do not represent the only possibility for implementing the method according to the invention. Rather, a basic concept or a possible implementation is described here in order to practically implement the method according to the invention for operating and / or decarbonizing an industrial production process using a heated melt 2. Based on this, a multitude of technical modifications and / or specifications compared to the described system 1 according to the invention are in principle possible. Since the system 1 according to the invention is designed for operating an industrial production process using the melt 2, the system 1 according to the invention has a vessel 3 in which the melt 2 to be heated can be received or is received.

[0075] The melt 2 is preferably designed as an immersion bath, in particular a galvanizing bath, or is used in a metallic coating process, such as galvanizing, in particular hot-dip galvanizing. Accordingly, the heated melt 2 is provided and / or stored as a coating compound.

[0076] To heat the melt 2, the system 1 comprises at least one non-electrical heating device 4; preferably, a plurality of non-electrical heating devices 4 are provided. The non-electrical heating device 4 is preferably designed to burn a fuel gas or as a gas burner to enable the heat input into the melt 2 to be heated.

[0077] Accordingly, the non-electrical heating device 4 is connected to an energy source 5, preferably a gas source. The energy source 5 can provide fuel gas, for example natural gas, in particular natural gas mixed with hydrogen or pure hydrogen, for operating the non-electrical heating device 4.

[0078] If a mixed gas is used, a further upstream hydrogen source can be provided to add hydrogen to the gas originating from energy source 5, preferably natural gas, as a further gaseous component, or vice versa. The hydrogen is preferably generated from renewable energy sources, produced by electrolysis of water, whereby the water is split into hydrogen and oxygen using renewable electricity. In this respect, it is preferably so-called "green hydrogen."

[0079] For additional or optional heating of the melt 2, the system 1 comprises at least one electrical heating device 6, preferably a plurality of electrical heating devices 6. The electrical heating device 6 can accordingly be connected to a power grid 7. The power grid 7 is preferably a public power grid. Preferably, the power grid 7 or the electrical energy source contains electricity generated at least partially from renewable energy sources, which is fed into the power grid 7 as needed.

[0080] The system 1 according to the invention has a control and / or regulating device 8 for selectively heating the melt 2 by means of the non-electrical heating device 4 and / or the electric heating device 6.

[0081] The control and / or regulating device 8 is designed to at least partially extract an excess current occurring in the power grid 7 and to operate the electrical heating device 6 with the extracted excess current.

[0082] For the preferably automatic and / or frequency- or internet-controlled detection of excess current, the control and / or regulating device 8 has a detection device 9 for detecting the occurrence of excess current and a control and / or regulating device 10 for operating the electrical heating device 6 and the non-electrical heating device 4 after the detection of excess current. A detection device 9 is also understood to be a device for receiving signals transmitted by the grid operator or a third party, whereby the transmission of a signal occurs automatically when current peaks or excess current are present in the grid or are imminent. Signals of this type are automatically generated and transmitted by the grid operator or third parties.

[0083] The detection device 9 and the control and / or regulating device 10 are preferably connected to each other by signaling.

[0084] This signaling connection is preferably implemented such that, upon the occurrence and / or detection of excess current by the detection device 9, the control and / or regulating device 10 is activated to draw excess current from the power grid 7. The control and / or regulating device 10 is designed to control and / or regulate the non-electrical heating device 4 and the electric heating device 6. For this purpose, the control and / or regulating device 10 is signal-connected to the non-electrical heating device 4 and the electric heating device 6.

[0085] The control and / or regulating device 10 is designed to regulate the heat energy introduced into the melt 2 by the non-electrical heating device 4 and the electric heating device 6, specifically as a function of the excess current occurring in the power grid 7 and / or the temperature of the melt 2. Preferably, the regulation or control is carried out in such a way that a constant heat input into the melt 2 occurs over the entire occurrence of the excess current and / or a constant, defined process temperature of the melt 2 is ensured.

[0086] For this purpose, the control and / or regulating device 10 is designed to increase the power of the electrical heating device 6 upon occurrence and / or detection of the excess current and, preferably simultaneously, to decrease the power of the non-electrical heating device 4, preferably in such a way that the total heat input coupled into the melt 2 by the combination of the non-electrical heating device 4 and the electrical heating device 6, or the associated process temperature, remains constant. In the event of fluctuating excess current, the control and / or regulating device 10 is also designed to adjust the heat input introduced into the melt 2 by the heating devices 4, 6 accordingly, in order to ensure a constant heat input or a constant process temperature even in the event of fluctuating excess current.

[0087] To control or regulate the heating devices 4, 6, a process temperature in the melt 2 is preferably continuously measured as a controlled variable and compared with a reference variable or the desired process temperature of the melt 2. Due to any control deviation that may occur, the power input of the heating devices 4, 6 is then adjusted by means of the control and / or regulating device 10. In principle, it is also possible to overheat the melt 2 using the electrical heating device 6 in a temperature range of up to 20 °C above the usual process temperature and then to stop the electrical heating for a time until the temperature of the melt 2 drops back to the usual process temperature. The control and / or regulating device 10 is also designed to completely shut down the non-electrical heating device 4 orto heat the melt 2 exclusively by means of the electrical heating device 6. The heating of the melt 2 is then preferably carried out exclusively by means of the electrical heating device 6 or by exclusively using excess electricity.

[0088] However, the heating of the melt 2 can also be carried out by exclusively operating the non-electrical heating device 4 by means of the control and / or regulating device 10, wherein the control and / or regulating device 10 is accordingly designed to completely shut down the electrical heating device 6.

[0089] It should be noted that the system 1 can also have a further or second (not shown) control and / or regulating device, which can be provided in addition to the described or shown control and / or regulating device 8. This further or second control and / or regulating device can be provided in particular for operating the process, provided there is no excess power and / or is designed to operate the process or the non-electrical heating device 4 and / or the electric heating device 6 independently of the power grid 7. Accordingly, the described or first control and / or regulating device 8 is only used when excess power is present or detected in the power grid 7.

[0090] Likewise, at least one switching device can be provided to effect switching between the non-electrical heating device 4 and the electric heating device 6. This switching device is preferably also signal-connected to the control and / or regulating device 8 or the control and / or regulating device 10.

[0091] The heating of the melt 2 is thus carried out optionally by means of the electrical heating device 6 and / or the non-electrical heating device 4. The term optionally ultimately defines three different process modes, according to which the heating is carried out exclusively by the non-electrical heating device 4 (first process mode), by both the non-electrical heating device 4 and the electrical heating device 6 (second process mode) or exclusively by the electrical heating device 4 (third process mode).

[0092] In order to control and / or regulate the heating devices 4, 6 and / or to change the process modes in question, the heating devices 4, 6 are signal-connected to the control and / or regulation device 8 of the system 1.

[0093] The control of the heating devices 4, 6 via the control and / or regulating device 8 is carried out in particular in such a way that a defined process temperature or a predetermined temperature interval of the melt 2 is specified as a target or controlled variable. For this purpose, the control and / or regulating device 8 is preferably supplied continuously or at intervals with actual temperatures of the melt 2, on the basis of which the heating devices 4, 6 are then selectively controlled in order to continuously provide the melt 2 at the defined process temperature.

[0094] It is understood that the system 1 according to the invention may have temperature sensors or thermocouples (not shown) in the region of the boiler 3 and / or the melt 2 in order to determine the actual temperature of the melt 2.

[0095] Due to the combined heating by means of the non-electrical heating device 4 and the electric heating device 6, decarbonization can take place compared to processes operated only with a non-electrical heating device 4.

[0096] Having said this, the method according to the invention is described below using the system 1 according to the invention.

[0097] According to the method, if excess power occurs in the power grid 7, it is at least partially withdrawn from the power grid 7 and used to operate the electric heating device 6. The presence of the excess power is detected, preferably automatically, by the detection device 9, with the result that the regulation or control of the heating devices 4, 6 takes into account the withdrawn excess power.

[0098] Specifically, it is provided that the control and / or regulating device 10 of the control and / or regulating apparatus 8 is initially designed to operate the electrical heating device 6 using the surplus power taken from the power grid 7.

[0099] At the same time or alternatively, the control and / or regulating device 10 is also designed to reduce or shut down the heating power of the non-electrical heating device 4 as a result of the excess current that occurs and the heating operation taken over by the electrical heating device 6.

[0100] The control of the heating devices 4, 6, in particular the starting up of the electrical heating device 6 and the shutting down of the non-electrical heating device 4, continues to be carried out under the condition of maintaining a defined process temperature of the melt 2, which continues to be processed as a reference variable or target variable in the control and / or regulating device 8 or the control and / or regulating device 10.

[0101] It has proven expedient that, before the excess current is detected, the melt 2 is initially heated exclusively by the non-electrical heating device 4, which is operated or fed by the energy source 6. Upon detection of the excess current from the power grid 7, the electric heating device 6 is then switched on, with the result that the heat input previously provided exclusively by the non-electrical heating device 4 is now initially partially or completely taken over by the electric heating device 6.

[0102] As a result, the exhaust emissions from the non-electrical heating system 4 are reduced, along with the decarbonization of the industrial production process achieved by the method. At the same time, the use of the surplus electricity is associated with an improvement in the grid serviceability of the power grid 7, since the overloading of the power grid 7 that would otherwise be expected if the surplus electricity were not consumed is avoided or compensated for.

[0103] Especially in the case of prolonged or excessive excess current, it has proven to be expedient to completely shut down the heating via the non-electrical heating device 4 and to heat the melt 2 exclusively via the electrical heating device 6.

[0104] A possible embodiment of arrangements and / or designs of the heating devices 4, 6 for heating the melt 2 held in the vessel 3 is described below with reference to Fig. 2.

[0105] In this context, it should be noted that the arrangement shown represents a possible technical variant for implementing the method according to the invention, but it is not to be understood as mandatory or the only technical possibility. Therefore, the teaching of the invention is not limited to the arrangement illustrated below, and a multitude of other embodiments are possible or conceivable.

[0106] The connection and / or design of the heating devices 4, 6 for heating the melt 2 is preferably carried out in such a way that the process can be carried out independently of one another over the entire process time or using exclusively the non-electrical heating devices 4 or the electric heating devices 6, wherein a combined use of the heating devices 4, 6 is also possible with any desired proportion of the heat input introduced by the heating devices 4, 6.

[0107] In particular, the electrical heating devices 6 are designed and / or arranged such that the heating of the melt 2 in the range of a defined process temperature is possible exclusively by electrical heating, preferably using only excess power from the power grid 7. In the embodiment shown in Fig. 2, a furnace chamber 11 is provided that at least partially surrounds the vessel 3, which is preferably designed as an annular chamber and / or surrounds the vessel 3 on all sides.

[0108] The furnace chamber 11 is delimited on the inside by the wall of the boiler 3 and on the outside by a furnace housing 12, wherein the boiler 3 is accommodated in the furnace housing 12.

[0109] In the illustrated and preferred embodiment, a plurality of rod-shaped electrical heating devices 6 are provided, which are introduced or immersed into the melt 2 for direct contact or heating. The electrical heating devices 6 can be arranged within the melt 2, preferably in pairs on opposite end faces of the vessel 3, in particular in a perpendicular or vertical orientation in the use state.

[0110] In addition, a plurality of non-electrical heating devices 4 are provided, which are designed as gas burners. The non-electrical heating devices 4 are designed to heat the furnace chamber 11 and / or are arranged on or in the furnace chamber 11, preferably in the region of at least one side wall, in particular a longitudinal side wall, of the boiler 3. However, non-electrical heating devices 4 and / or electrical heating devices 6 can also be arranged on opposite side walls, in particular a longitudinal side wall, of the boiler 3.

[0111] It can be provided that the non-electrical heating devices 4 are arranged and / or accommodated on or in the furnace housing 12, preferably in the region of at least one side wall, in particular the longitudinal side wall, of the furnace housing 12.

[0112] In addition to or as an alternative to the electrical heating devices 6 arranged in the melt 2, at least one electrical heating device 6 can also be arranged in the furnace chamber 11. The electrical heating device 6 can preferably be designed as an electrical and / or flexible heating conductor, wherein the length of the electrical conductor exceeds the length of the vessel 3 by several times. The electrical heating device 6 is preferably assigned to the same side wall, in particular the longitudinal side wall, of the vessel 3 as the non-electrical heating devices 4.

[0113] In the illustrated and preferred embodiment, the electrical heating device 6 is arranged in a loop-like or meander-like manner around the non-electrical heating devices 4, preferably in such a way that the non-electrical heating devices 4 are surrounded by the electrical heating device 6.

[0114] It is understood that other arrangements of the non-electrical heating devices 4 or the electric heating device 6 may also be provided.

[0115] According to an embodiment not shown, it can also be provided that all or at least some of the non-electrical heating devices 4 or heating burners are decoupled from the boiler 3 or furnace chamber 11 and / or arranged in a heating chamber upstream of the boiler 3. This heating chamber then functions as an upstream heating chamber in which preheated heating air or heated heating gas is provided. In contrast, the electrical heating devices 6 are decoupled from the non-electrical heating devices 4, are immersed directly in the melt 2 and / or are arranged in the furnace chamber 11.

[0116] Alternatively or additionally, it can also be provided that all or at least some of the electrical heating device(s) 6 are decoupled from the boiler 3 or furnace chamber 11 and / or are arranged in a further heating chamber or in the heating chamber upstream of the boiler 3. This one or more further heating chambers then functions as an upstream heating chamber in which already heated heating air or heated heating gas is provided. In contrast, the non-electrical heating devices 4 are designed and / or arranged decoupled from the electrical heating devices 6 for heating the furnace chamber 11. By providing heated heating air in the upstream heating chamber, this heated heating air can be introduced into the furnace chamber 11 with rapid reaction, provided that, preferably starting from the electrical heating of the melt 2, the system switches back to heating the melt 2 by means of the non-electrical heating device 4.For this purpose, the furnace chamber 11 can be flooded with preheated heating air to ensure that production operations or the defined process temperature of the melt 2 are maintained. For this purpose, the furnace housing 12 can have a corresponding inlet and / or outlet line 13 to introduce a heated heat flow or heated heating air into the furnace chamber 11 as needed and / or to discharge used process air from the furnace chamber 11.

[0117] The indirect heat coupling by means of the at least one electrical heating device 6 and / or the at least one non-electrical heating device 4 arranged in the furnace chamber 11 takes place in particular in such a way that the air in the furnace chamber 11 is heated via a side wall, in particular a longitudinal side wall, and the wall of the vessel 3 is heated therethrough. As a result, the melt 2 is initially heated on the wall side. Due to the associated heat convection, a flow or circulation of the melt 2 heated on the wall side occurs into the interior of the vessel 3, so that heated melt 2, starting from the wall sections, also reaches the interior of the vessel 3 and, in this way, a thorough mixing of the heated melt 2 takes place within the vessel 3.

[0118] The electrical heating devices 6 are preferably specially insulated or protected from the aggressive exhaust air of the non-electrical heating devices 4, in particular if the heating devices 4, 6 are arranged or accommodated together in the furnace chamber 11.

[0119] The supply and / or discharge line 13 is preferably closable as required and / or provided with a corresponding exhaust gas flap.

[0120] In addition, several thermocouples or sensors are provided on the vessel 3 in order to preferably continuously monitor and / or record the temperature of the melt 2 and / or the heating temperature in the furnace chamber 11. The temperature in the vessel 3 and / or in the furnace chamber 11 thus preferably functions as a controlled variable, which is fed accordingly to the control and / or regulating device 8 or the control and / or regulating device 10 for the purpose of controlling the non-electrical heating device 4 and the electric heating device 6. As a result, the heat input of the electric heating device 6 and / or the non-electrical heating device 4 is regulated or adjusted as needed to avoid system-critical temperatures and / or to permanently maintain the melt 2 at a defined process temperature.

[0121] The control and / or regulating device 8 can have a switching device to implement an on-demand switching of the heating operation between the electrical heating device 4 and the non-electrical heating device 6. The switching device can have corresponding switching and / or line components for this purpose.

[0122] The non-electrical heating devices 4 are preferably arranged as a matrix and / or in a fixed group pattern in the furnace chamber 11. The non-electrical heating devices 4 are preferably assigned to a side wall, in particular a longitudinal side wall, of the boiler 3.

[0123] Alternatively or additionally, the non-electrical heating devices 4 and / or the electrical heating devices 6 can be assigned to opposite side walls, in particular longitudinal side walls, of the boiler 3.

[0124] For defined heat input, the non-electrical heating devices 4 and / or the electrical heating devices 6 can be controlled or regulated individually or in defined zones or groups, in particular by means of the control and / or regulating device 8 and / or the control and / or regulating device 10.

[0125] If the control and / or regulating device 8, in particular the detection device 9, receives a signal from the power grid 7, in particular frequency- or internet-controlled, indicating that there is excess power in the power grid 7, the heat output or combustion output of the non-electrical heating devices 4 is reduced by switching off one or more non-electrical heating devices 4 and / or reducing the heat output or combustion output of one or more non-electrical heating devices 4. At the same time, the electric heating drive is taken up via the electric heating devices 6, using the excess power taken from the power grid 7 for this purpose.

[0126] For this purpose, after a possibly defined transition period, the non-electrical heating operation can be completely shut down so that no heat is coupled via the non-electrical heating devices 4. The melt 2 is then preferably heated exclusively via the electrical heating devices 6, which are incorporated in the melt 2. Through convection and mixing in the vessel 3, the entire melt 2 is then uniformly heated or heated by means of the electrical heating devices 6.

[0127] The heating of the melt 2 via the electrical heating devices 6 can be carried out in such a way that the melt 2 is heated above the process temperature or a defined process temperature interval, preferably by at least 20 °C, preferably at least 40 °C above the process temperature. After this overheating, the heating by means of the non-electrical heating devices 4 and / or the electrical heating devices 6 can then be reduced or completely stopped, such that the melt 2 cools again from the overheating above the process temperature.If the melt 2 reaches or falls below the process temperature again, the melt 2 can be heated again by means of the non-electrical heating devices 4 and / or the electric heating devices 6, preferably exclusively by means of the electric heating devices 6, preferably wherein the melt 2 is again heated above the process temperature in the above sense.

[0128] In this respect, heating intervals can be defined between which no heating of the melt 2 occurs. Within the heating intervals, the melt 2 is again heated, preferably exclusively by means of the electrical heating device 6.

[0129] The duration of the heating intervals is flexibly adjustable and is preferably carried out in such a way that continuous operation of the coating process is possible both within and between heating intervals. List of reference symbols:

[0130] system

[0131] melt

[0132] Boiler non-electric heating device

[0133] Energy source electric heating device

[0134] power grid

[0135] Control and / or regulating device

[0136] Detection device

[0137] Control and / or regulating device

[0138] furnace room

[0139] Furnace housing

[0140] Intake and / or discharge

Claims

Patent claims:

1. Method for operating and / or decarbonising a production process, in particular an industrial one, preferably a coating process, such as galvanising, in which a heated melt (2) is provided and / or kept in stock, wherein the heating of the melt (2) is carried out optionally by means of at least one electrical heating device (6) and / or at least one non-electrical heating device (4), and wherein, when an excess current occurs in the power grid (7), this excess current is at least partially taken from the power grid (7) and used to operate the electrical heating device (6).

2. Method according to claim 1, characterized in that the occurrence of the excess current is detected by a detection device (9) and the electrical heating device (6) and the non-electrical heating device (4) are operated after the detection of the excess current by means of a control and / or regulating device (10), preferably in such a way that the melt (2) is provided and / or maintained in a defined process temperature range using excess current.

3. Method according to claim 1 or 2, characterized in that the production process is carried out continuously during the electrical heating (6) and, in particular, in a defined temperature range.

4. Method according to one of the preceding claims, characterized in that upon occurrence and / or detection of the excess current, the heating power of the non-electrical heating device (4) is reduced and the operation of the electrical heating device (6) is started, preferably wherein the operation or the heating by means of the non-electrical heating device (4) is terminated and the heating of the melt (2) takes place exclusively by means of the electrical heating device (6) using excess current.

5. Method according to one of the preceding claims, characterized in that the heating of the melt (2) before occurrence and / or detection of the excess current is preferably carried out exclusively by the non-electrical heating device (4) and the electrical heating device (6) is connected to the non-electrical heating device (4) upon occurrence and / or detection of the excess current.

6. Method according to one of the preceding claims, characterized in that the non-electrical heating device (4), preferably exclusively, is operated with hydrogen as fuel gas or a hydrogen-containing fuel gas and / or mixed gas, in particular a hydrogen-natural gas mixed gas, preferably wherein the fuel gas and / or mixed gas contains at least 1 to 80 vol.%, preferably 25 to 90 vol.%, particularly preferably 50 to 100 vol.% hydrogen.

7. Method according to one of the preceding claims, characterized in that the heating of the melt (2) takes place at least partially indirectly via a vessel (3) receiving the melt (2), preferably wherein a furnace chamber (11) surrounding the vessel (3) is heated by means of the electrical and / or non-electrical heating device (4, 6), in particular wherein the furnace chamber (11) is heated by means of the non-electrical heating device (4) and the melt (2) is additionally heated directly and / or in a contact-bound manner by means of an electrical heating device (6) preferably arranged in the melt (2).

8. Method according to one of the preceding claims, characterized in that the melt (2) is kept at a process temperature which is at least 10 °C, preferably at least 20 °C, in particular at least 30 °C, above a melting temperature of the melt (2); and / or that the melt (2) is kept at a process temperature in the range of 200 °C to 1200 °C, preferably in the range of 350 °C to 470 °C or preferably in the range of 510 °C to 610 °C.

9. Method according to one of the preceding claims, characterized in that the production process is carried out as hot-dip galvanizing, in particular batch galvanizing, and / or that the melt (2) is provided and / or kept as a zinc alloy.

10. System (1) for operating and / or decarbonizing a preferably industrial production process using a melt (2), preferably a coating process, such as galvanizing, in particular for carrying out the method according to one of the preceding claims, with a boiler (3) for the melt (2) to be heated, with at least one electrical heating device (6) and at least one non-electrical heating device (4), and with at least one control and / or regulating device (8) for selectively heating the melt (2) by means of the electrical heating device (6) and / or the non-electrical heating device (4), wherein the control and / or regulating device (8) is additionally designed to at least partially withdraw an excess current occurring in a power grid (7) and to operate the electrical heating device (6) with the withdrawn excess current.

11. System according to claim 10, characterized in that the control and / or regulating device (8) has a detection device (9) for detecting the occurrence of the excess current and a control and / or regulating device (10) for operating the electrical heating device (6) and the non-electrical heating device (4) after the detection of the excess current, in particular such that the melt (2) is provided and / or held in a defined process temperature range after the detection.

12. System according to claim 10 or 11, characterized in that a furnace chamber (11) is provided which at least partially surrounds the boiler (3), preferably wherein the electrical heating device (6) and / or the non-electrical heating device (4) is / are arranged in the furnace chamber (11), in particular wherein the non-electrical heating device (4) is / are arranged in the furnace chamber (11) and the electrical heating device (6) is arranged in the interior of the boiler (3) for contacting the melt (2) and / or for directly heating the melt (2).

13. Use of a system according to one of the preceding claims for decarbonization, in particular for reducing and / or avoiding the formation of climate-damaging emissions, such as carbon oxides, when operating a heat-consuming process, preferably a coating process, such as galvanizing.

14. Use of a system according to one of the preceding claims, in particular use according to claim 12, for removing excess current when current peaks occur and / or for increasing grid serviceability in a heat-consuming process, preferably a coating process, such as galvanizing.

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