Methods and systems for the operation and / or decarbonization of industrial production processes in particular.

Abstract

The present invention relates particularly to a method for operating and / or decarbonizing industrial production processes, preferably coating processes such as zinc plating, wherein a heated molten material is provided and / or kept available, the molten material is selectively heated by at least one electric heating device and / or at least one non-electric heating device, and where there is surplus power in the power grid, at least a portion of it is taken from the power grid and used to operate the electric heating device.

Description

Technical Field

[0001] The present invention relates to a method and a system for the operation and / or decarbonization of a process in which a heated melt is provided and / or stored, particularly in an industrial production process, preferably a coating process such as zinc plating. Further, the present invention also relates to the use of such a system in a heat-consuming process, preferably a coating process such as zinc plating.

Background Art

[0002] The present invention relates to the field of operating industrial processes, in the context of which the manufacture, treatment, and / or processing of actual articles or products are carried out on a commercial scale. For the purposes of the present invention, "industrial process" is understood to particularly refer to the mass production and / or large-scale production of actual articles or members, or commercial processing, especially for the coating operation of workpieces.

[0003] Industrial production processes require a high level of process heat, particularly in process steps intended to change heat treatment or material properties and / or characteristics. Due to the industrial scale of the production process, it is natural that the heat or energy supply required for this must be ensured continuously and / or throughout the production process, and thus permanently.

[0004] In this context, the present invention is particularly directed to heat-consuming production processes that are carried out using a heated melt or in which a heated melt is provided and / or stored. The heated melt is preferably understood to be any type of liquid metal and alloy that is used in various ways in industrial production processes, for example in the casting or coating of workpieces.

[0005] However, the initial starting point of the present invention is a coating process in which a layer of amorphous material that adheres tightly to the surface of a workpiece is applied. For this purpose, a heated molten material that functions as the coating material is kept in reserve or provided as appropriate.

[0006] A coating process particularly frequently used in industry is zinc plating, especially hot-dip galvanizing, in which a metallic hot-dip galvanizing coating is applied to protect a workpiece from rust or corrosion by immersing it in a zinc-containing coating compound.

[0007] In particular, in zinc plating, it is extremely important that the molten zinc provided for coating is maintained at a predetermined process temperature, either permanently or with a constant heat supply. This is because there is a dependency between the coating quality to be achieved and the temperature of the molten material or coating material; only then can accurate process control be guaranteed.

[0008] In practice, the process heat required for the production processes described above, particularly the coating or galvanizing processes, is supplied by burning fossil fuels, usually gases such as natural gas. For example, in practice, galvanizing furnaces containing coating or galvanizing materials are heated using gas burners powered by natural gas. [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, the use of natural gas in industrial processes is problematic because it involves the emission of substances that have adverse climate effects, such as carbon dioxide. In addition to this lack of sustainability and climate impact, the use of natural gas as an energy source, particularly in industrial processes, also presents many geopolitical challenges.

[0010] The aforementioned drawbacks are particularly significant in industrial processes involving the use of molten materials. This is because the continuous heating of the molten material or heating to relatively high process temperatures requires very high energy inputs and ultimately high consumption of fossil fuels or natural gas required for this purpose.

[0011] Despite the aforementioned drawbacks, the implementation of natural gas for process heat generation in industrial production processes is typically carried out via numerous gas burners, essentially ensuring sufficient thermal coupling and thus reliable heating of the molten material, making it inherently suitable for complex process control for the continuous and predetermined heating of the molten material. In this regard, given the high costs associated with transforming plant technology, replacing natural gas fuel as an energy source with other means has been avoided, particularly in coating processes such as zinc plating.

[0012] The present invention aims to avoid, or at least substantially reduce, the aforementioned drawbacks of the prior art. [Means for solving the problem]

[0013] According to the present invention, in order to solve the above objectives, a method and system for operating and / or decarbonizing industrial production processes is proposed, wherein the heating of the molten material is carried out by at least one electric heating device and / or at least one non-electric heating device. This means that the heating can be operated by electric only, non-electric only, or a combination of electric and non-electric (hybrid).

[0014] In developing this invention, it was recognized that there are many advantages to using electric heating devices as an option, rather than heating the molten material using only non-electric or gas-based energy sources. The molten material can be heated by electric thermal storage, in addition to non-electric heating devices, or as a complete replacement for non-electric or gas-based heating devices.

[0015] In this regard, the terms “optionally” or “either” ultimately encompass three different process methods or modes for providing the total power required for heating an industrial process or molten material. Thus, depending on the process, the molten material may be heated by non-electric heating devices only (first process mode). Furthermore, it may be possible to combine heat input using both non-electric and electric heating devices (second process mode). Furthermore, it may be possible to heat the molten material using only electric heating devices (third process mode).

[0016] The optional use of electric heating devices avoids or mitigates the drawbacks associated with non-electric or gas-based heating devices, particularly those related to climate-detrimental emissions such as carbon dioxide. This lays the foundation for the decarbonization intended in this process, because the replacement with electric heating devices employed in this invention allows for the combination of the heat necessary to heat the molten material while significantly reducing, and in some cases completely avoiding, climate-detrimental emissions such as carbon dioxide.

[0017] In this regard, the term “decarbonization” as used in the context of this invention is understood to refer to the avoidance or at least reduction of climate-damaging emissions, such as those produced in conventional industrial processes, particularly in the combustion of fossil fuels like natural gas. The term “climate-damaging emissions” should be interpreted broadly and encompass all gaseous emissions that negatively impact the climate. This invention is primarily aimed at avoiding or reducing carbon dioxide (CO2), but is not limited to it. For example, carbon monoxide, methane, nitrous oxide, or other climate-damaging greenhouse gases (GHGs) can also be climate-damaging emissions in the sense taught by this invention.

[0018] In other words, the present invention proposes a hybrid heating concept in which an electric heating device is optionally or at least partially used for the continuous heating of a molten material, thereby achieving the desired decarbonization of the industrial process to be operated.

[0019] The term “permanent” provision or availability of the molten material preferably refers to a period of at least one hour, preferably at least five hours, and particularly at least ten hours, which may range from one day or 24 hours to several days, depending on the extent of process control. In this regard, the term “permanent” should preferably be understood in a broad sense.

[0020] In particular, with respect to coating processes or galvanizing, the term “permanent” defines the operating time during which the molten material held in the tank can be used steadily and / or functionally to coat a workpiece as part of the coating process without draining or preparation.

[0021] Furthermore, the term “melt,” as preferably used in the context of the present invention, should be understood to preferably refer to a non-ferrous metal coating material. This is supplied and / or held in a tank or other holding means and used as a steady method or immersion bath, maintaining at least a substantially constant volume or mass throughout the entire process time, i.e., without draining from the tank. In this respect, the melt in the sense of the present invention should preferably not be understood as a casting melt for casting or primary forming of the corresponding cast product. However, the use of the method according to the present invention may also be effective in casting processes, and is therefore expressly covered by the teachings of the present invention.

[0022] In developing the present invention, which incorporates the hybrid heating strategy described above for industrial processes, it was necessary to overcome several technical biases. Depending on the application or specific requirements, industrial processes have historically used burners heated by natural gas or other fossil gaseous energy sources. Alternatively, heat-consuming processes that use only electricity, either by induction heating or resistance heating, are known. Due to the complex process control associated with heat-consuming processes, hybrid use combining electric and non-electric energy sources has not been considered until now. In particular, since changing energy sources or associated energy inputs involves complex conversion and switching measures and the resulting interruption of heat supply, the provision of hybrid systems has been considered disadvantageous and unbalanced in other technical fields as well. This interruption can last from minutes to hours and involves technical precautions to prevent production interruptions and drops in process temperature. As a result, the use of hybrid systems or parallel operation of electric and non-electric heating in heat-consuming processes has not been practically considered until now.

[0023] Deviating from this common view, it has been newly recognized, in the context of the solutions according to the present invention, that a hybrid heating system comprising electric and non-electric heating devices is very suitable for heating molten materials held or supplied for industrial production processes, particularly coating processes.

[0024] In the context of the present invention, molten materials requiring continuous heating, preferably metal molten materials and / or non-ferrous molten materials, particularly zinc-containing metal molten materials, have been found to be suitable for hybrid heat supply because their temperature changes relatively slowly during heat supply and / or heat removal due to their relatively high thermal inertia, i.e., relatively high mass and heat capacity. This results in a relatively large time frame or reduced sensitivity with respect to the above process mode, selection of heating equipment, switching from one heating equipment to another, and implementation of the hybrid heating system.

[0025] As a result, the present invention for the first time proposes in the form of a complete concept that in order to decarbonize a heat-consuming process, the heating of the melt used in this process should not be carried out only by gas-based or non-electric heating, but should also be carried out at least partially or optionally by an electric heating device. This enables parallel or simultaneous heating by a non-electric heating device and an electric heating device. Simultaneous heating by a non-electric heating device and an electric heating device is also possible.

[0026] Due to the inertia of the melt, the optional heating by the electric heating device and / or non-electric heating device provided in this process ensures that even if there is a short interruption in the heat input to the melt to be heated, it does not lead to a decrease in process performance compared to non-electric or gas-based heating known in the prior art.

[0027] As a specific supplement to the above hybrid heating, the present invention also provides that in order to operate the electric heating device, at least part of the surplus current generated in the power grid, especially the public power grid, is extracted and used to operate the electric heating device.

[0028] In this context, surplus power is power that can only be utilized with an output that varies over time and thus may lead to an over-supply or excess capacity of power in the power grid. In this regard, due to the over-supply of surplus power in the power grid, situations where electrical energy or power cannot be fully consumed are occurring more and more frequently.

[0029] Surplus power, i.e., electrical energy whose output varies over time, is particularly due to the proportion of renewable energy. Its power share is on an increasing trend and is preferentially supplied to the power grid. The underlying energy sources, namely the sun, wind, and water, are not always available over time, and it is difficult to predict their availability. Therefore, fluctuations in output and excess capacity, or the period of surplus power, are ultimately inevitable. For example, strong winds in a short period may result in an excessive supply of power or a power peak to the power grid, and the resulting surplus power has the problem that it must be diverted or consumed to avoid overloading the power grid and the associated damage.

[0030] The term "power grid" used in the context of the present invention is preferably interpreted broadly and, in power engineering, refers to a network for the transmission and distribution of electrical energy. It consists of electric wires such as overhead lines and underground cables, and related facilities such as switchyards and substations. A large-scale, spatially adjacent, and electrically connected power grid is called an interconnected power grid system, and a small-scale, spatially separated power grid is called an independent power grid. The method according to the present invention is particularly preferably used in a power grid that obtains at least part of its electrical energy from renewable energy.

[0031] In the near future, the supply to the power grid associated with the increasing proportion of renewable energy from the sun, wind, and water will increasingly cause power peaks and / or surplus power. This surplus power can only be incompletely purchased by power consumers, and thus, as so-called surplus power, it is offered to the power market at a price significantly lower than the production cost, or at a price low relative to the energy content compared to fossil fuels of the same calorific value, or for free, i.e., without consideration, and even at a negative price.

[0032] To date, in relation to metal smelting, overload current has not been used to reduce power peaks. Instead, attempts have been made to store surplus power or power peaks in storage systems such as batteries or pumped-storage power plants and resupply them to the grid. However, the use of battery systems presents problems in terms of cost and associated resource requirements. Particularly from an environmental standpoint, the use of batteries, which have a limited lifespan and degrade in performance over time or with increasing usage, is counterproductive and therefore not effective from a sustainability perspective. Furthermore, the recycling and disposal of batteries on the required scale is also known to be problematic.

[0033] It should also be noted that such buffer and storage systems are not a feasible solution because their construction is extremely expensive and depends on geographical conditions and high losses associated with energy conversion.

[0034] In this regard, concepts for effectively utilizing surplus electricity have not been adequately developed in practice. However, since this surplus electricity is mainly generated from renewable energy sources, how to handle it is an important aspect of energy transition.

[0035] The present invention makes it possible to use electrical energy generated from surplus current specifically for operating an electric heating device or for heating a molten material.

[0036] This requirement is based on the above recognition that it is feasible to heat molten materials using electric heating devices on an industrial scale in combination with non-electric heating devices.

[0037] Against this backdrop, the solution according to the present invention not only prevents overloading of the power grid but also contributes to the efficient utilization of surplus electricity mainly supplied from renewable energy sources such as solar, wind, and hydroelectric power.

[0038] As a result, the solution according to the present invention provides a specifically tailored concept by combining two findings, each of which is beneficial individually, with respect to decarbonization and / or avoidance of climate-detrimental emissions such as carbon dioxide, for a particular purpose.

[0039] Therefore, decarbonization is already achieved through the use of electric heating systems. This basic idea is completed or complemented by the additional requirement of specifically using surplus electricity to operate the electric heating systems. Since this surplus electricity is supplied mainly from renewable energy sources, the surplus electricity itself also comes from an emission-free power source. This makes it possible to achieve an emission-free process chain while completely avoiding the formation of climate-detrimental emissions such as carbon oxides.

[0040] In this regard, the solution according to the present invention contributes to the decarbonization of industrial production processes that use molten materials, while also providing integration of electricity generated from surplus power or renewable energy, thereby addressing aspects of grid maintainability and grid load reduction.

[0041] Based on the above basic considerations of the solution according to the present invention, the advantageous process aspects of the present invention will be described below.

[0042] The generation of excess current in the power grid can be detected by detection devices. This can preferably be done automatically, particularly by frequency control and / or internet control. Detection devices are understood to also include receiving devices such as signals that are transmitted manually or automatically by the power grid operator and received by receiving devices. After the excess current is detected, electric heating devices and non-electric heating devices are controlled and / or regulated by control and / or regulating devices. Thus, in the method of operating the production process, a period before the generation of excess current and a period after the generation of excess current are distinguished, and after the generation of excess current, control / regulation of electric heating devices and non-electric heating devices is preferably performed, and the excess current is used to operate the electric heating devices. The excess current is preferably used so that the heated molten material is provided and / or maintained within a predetermined process temperature range, particularly permanently or throughout the entire production cycle.

[0043] The operation of using surplus power to operate the electric heating system and shutting down the non-electric heating system as needed is preferably carried out so that the production process continues continuously while the electric heating is in operation. Therefore, using surplus power to operate the electric heating system does not result in any disadvantage compared to conventional non-electric or gas-based heating, and the use of hybrid heating with an electric heating system does not impose any constraints on the production process. The production process continues continuously even during the transition from one process to another.

[0044] With respect to specific process control, it is preferable that when excess current is generated and / or detected, the heating power of the non-electric heating device is reduced and the operation of the electric heating device is started, and more preferably, the operation of the non-electric heating device is terminated and the heating of the molten material is performed solely by the electric heating device using the excess current.

[0045] This type of process is particularly advantageous when surplus electricity is expected to be available for a longer period. In this case, the production process can be explicitly designed to run continuously using only electric heating, or only surplus electricity for this purpose. The non-electric heating system can be permanently deactivated, resulting in the complete elimination of fossil fuel use, thus achieving maximum decarbonization and / or avoidance of climate-detrimental emissions such as carbon oxides. However, the possibility of the non-electric heating system being restarted, starting with pure electric heating, cannot be ruled out. It is also possible to completely shut down the electric heating system or to heat using only the non-electric heating system. This is always done when it is expected that surplus electricity will no longer be available thereafter.

[0046] The reduction or shutdown of non-electric heating devices, and / or the activation or operation of electric heating devices, may be performed continuously or discontinuously. Preferably, the reduction of non-electric heating devices is offset by the corresponding activation of electric heating devices, and the shutdown or activation is automatically adjusted so that the total thermal energy and / or process temperature introduced into the molten material remains at least substantially constant throughout the entire production process. This avoids undesirable fluctuations in the processing temperature of the molten material. This is ultimately made possible by the control / adjustment of the continuously measured temperature of the molten material.

[0047] In this context, a transition time can be defined, its start defined by the detection of excess current and / or the start of the shutdown of the non-electric heating device and / or the start of the startup of the electric heating device. The end of the transition time is defined by the complete shutdown of the non-electric heating device and / or the complete startup of the electric heating device.

[0048] The transition time is preferably freely selectable, and the relatively high heat capacity of the molten material allows for a flexible and adaptable transition time in principle. However, these also depend on the total volume of the molten bath.

[0049] The transition time can range from a few seconds, for example, up to 45 seconds or up to 30 seconds, to several minutes, for example, 5 to 10 minutes, preferably 5 to 30 minutes, during which the non-electric heating device is completely shut down and the electric heating device is fully started. However, shorter or longer transition times are also possible, depending particularly on the available surplus current and the amount of molten bath.

[0050] Preferably, the molten material is heated by non-electric heating devices only before the generation and / or detection of excess current, and electric heating devices may be added to the non-electric heating devices when excess current is generated and / or detected. In this regard, it is preferable that the starting or operation of the electric heating devices is particularly linked to the generation of excess current. This ensures that heating is provided by non-electric heating devices only during times when there is no excess current in the power grid. However, it is understood that it is also possible to operate the electric heating devices without excess current, for example, by directly connecting to any power source, which is preferably supplied at least partially, and especially entirely, from a renewable energy source.

[0051] With regard to the operation of non-electric heating devices, a preferred method is to specify that the non-electric heating device is operated with a CO2-free or at least natural gas and / or CO2-reduced fuel gas, particularly pure hydrogen or hydrogen-containing fuel gas, such as a natural gas-hydrogen mixture.

[0052] According to this particularly preferred method, decarbonization is achieved not only by the use of electric heating devices but also by the modification of non-electric heating devices, thereby using or mixing hydrogen instead of pure fossil fuel gas or natural gas. The combustion products of hydrogen are mainly water vapor, which is beneficial in that it avoids the formation of climate-detrimental emissions such as carbon oxides produced during the combustion of natural gas.

[0053] Preferably, unless pure hydrogen is not yet available on a large-scale industrial and economical basis, it is particularly effective to mix hydrogen with a carrier gas, preferably natural gas, to obtain a hydrogen-containing fuel gas. The carrier gas or natural gas is preferably, at least in part, a process gas produced in an industrial process, such as mine gas and / or coke oven gas.

[0054] The hydrogen content in the gas mixture, particularly consisting of or containing natural gas and hydrogen, is preferably at least 20%, preferably at least 40%, particularly preferably at least 60%, and very particularly preferably at least 80% or 90%.

[0055] In particular, hydrogen-containing fuel gas is used to operate non-electrically heated devices, and the fuel gas contains at least 1 to 100 volume% of hydrogen, preferably 25 to 100 volume%, and especially preferably 50 to 100 volume%.

[0056] Particularly preferably, the non-electric heating device is operated exclusively and / or with 100% hydrogen, preferably pure hydrogen and / or green hydrogen.

[0057] In particular, so-called green hydrogen is used only for operating non-electrically heated equipment and / or as part of a mixture of pure fuel gas or, for example, natural gas. Green hydrogen is produced by the electrolysis of water, and the electricity required for this process is obtained from renewable energy sources.

[0058] Therefore, according to the present invention, it is also possible to operate a non-electric heating device at least partially using renewable energy, i.e., hydrogen obtained from a renewable energy source.

[0059] The preferred process control relating to the use of hydrogen, preferably green hydrogen, as described above, improves the decarbonization of the process according to the present invention and further optimizes the sustainability of the process according to the present invention, in addition to hybrid heating with electric heating energy in particular.

[0060] Thermal bonding to or heating of the molten material can preferably be performed at least partially indirectly through a container containing the molten material, preferably by heating an electric heating device and / or a non-electric heating device in a furnace chamber surrounding the container. In particular, the furnace chamber is heated by a non-electric heating device, and the molten material is preferably retrogradely and directly heated by an electric heating device placed within the molten material.

[0061] Therefore, non-electric heating devices and electric heating devices are preferably spatially separated. Preferably, the non-electric heating devices can be used to heat the tank walls in the furnace chamber, while the electric heating devices can be housed in the tank for direct contact with the molten material. In particular, this prevents the electric heating devices from coming into contact with the non-electric heating devices or harmful exhaust gases that may be generated during the combustion of the fuel gas. However, it is also possible to place the non-electric heating devices and electric heating devices together in the furnace chamber. For this purpose, preferably, rod-shaped electric heating devices can be provided with a protective layer to provide protection from exhaust gases discharged from non-electric or gas-based heating devices.

[0062] The molten material is preferably heated to a process temperature at least 10°C, preferably at least 20°C, and especially at least 30°C higher than the melting point of the molten material.

[0063] The molten material is preferably maintained 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.

[0064] Particularly preferably, the molten material can be maintained at a process temperature in the range of 400°C to 600°C, preferably in the range of 415°C to 470°C, or preferably in the range of 510°C to 610°C, particularly in the range of 520°C to 600°C. This temperature range is preferred in the zinc plating process, and the elevated temperature range of 510°C to 610°C or 520°C to 600°C is provided for high-temperature zinc plating.

[0065] In particular, the molten material is provided and / or stored in a metal coating process as an immersion bath, especially a zinc plating bath, and at least one component to be coated with the molten material is immersed in the molten material and then withdrawn from the molten material.

[0066] Particularly preferably, the molten material or immersion bath is provided as a molten metal alloy. Preferably, a molten zinc alloy is provided or used as the molten material.

[0067] The process according to the present invention has been found to be particularly useful for hot-dip galvanizing, especially batch galvanizing. In this process, the material or component to be coated, preferably steel or a steel component, is immersed in a heated kettle containing a liquid zinc alloy at a temperature of about 400°C to 600°C, either continuously (e.g., strips and wires) or individually (e.g., components). As a result, a durable alloy layer of iron and zinc is formed on the steel surface or material surface, and a very strong zinc or zinc alloy layer is formed on top of it.

[0068] The method according to the present invention enables a continuous production process, particularly a hot-dip galvanizing process. This eliminates any loss in terms of the temperature and / or quality of the molten material compared to heating molten material based solely on non-electric or gas-based heating known in the prior art. At the same time, as detailed above, the process control according to the present invention makes it possible to achieve significantly improved sustainability or grid utility through associated decarbonization.

[0069] Subsequently, process control according to the present invention makes it possible to continuously supply and / or retain the molten material at the process temperature for a period of at least 1 hour, preferably at least 5 hours, and particularly preferably at least 10 hours.

[0070] Alternatively or additionally, the molten material may be supplied in masses or dimensions conventional for hot-dip galvanizing or industrial galvanizing, preferably in masses of 200 to 800 tons, preferably 250 to 750 tons, and especially 300 to 700 tons, to a tank specifically intended for industrial coating processes or industrial galvanizing.

[0071] However, it should be noted that the process according to the present invention is not limited to zinc plating or coating processes. Ultimately, the teachings of the present invention are applicable to all coating processes known in the prior art, insofar as the heated molten material is used or provided as the relevant coating composition.

[0072] The following describes, in accordance with further aspects of the present invention, a system according to the present invention for the operation and / or decarbonization of industrial processes, preferably industrial production processes.

[0073] More specifically, the present invention also relates to a system for operating and / or decarbonizing a preferred industrial production process using a molten material, preferably a coating process such as zinc plating, and is provided with a tank for the molten material to be contained and heated. The system according to the present invention has at least one electric heating device and at least one non-electric heating device.

[0074] According to the present invention, the system has at least one control and / or regulating device for selectively heating a molten material by an electric heating device and / or a non-electric heating device, the control and / or regulating device being additionally designed to extract at least partially surplus current generated in the power grid and to operate the electric heating device with the extracted surplus current. In this way, the above-mentioned advantages or special features of the present invention can be implemented by the device.

[0075] Therefore, the system according to the present invention is specifically designed or conceptualized for the implementation of the method described above. The advantages mentioned with respect to the method above also apply to the system.

[0076] In a further preferred embodiment of the present invention, the control and / or regulating device includes a detection device for detecting the occurrence of excess current and a control and / or regulating device for operating an electric heating device and a non-electric heating device after the excess current has been detected. The detection device may also be designed as a receiving device for receiving signals transmitted by a power grid operator or a third party when excess current occurs. The control and / or regulating device may include the detection device and the control and / or regulating device as a higher-level assembly. In principle, it is understood that the detection device and the control and / or regulating device can also be designed as modules or units separated from each other according to the device and connected to each other by signaling technology. In this case, the control and / or regulating device should be understood abstractly or as a higher-level designation for such structural unit unrelated to the device.

[0077] In a further preferred embodiment of the present invention, a furnace chamber is provided that at least partially encloses the tank, and preferably an electric heating device and / or a non-electric heating device are designed to heat the furnace chamber and / or are located on or inside the furnace chamber. In particular, the non-electric heating device is located on or inside the furnace chamber, the electric heating device is located in contact with the molten material or to directly heat the molten material inside the tank, or the electric heating device is located outside or in the outer wall area of ​​the tank. By physically separating the electric heating device from the non-electric heating device, it is possible to prevent the electric heating device from coming into contact with combustion gases emitted from the non-electric heating device. In this way, the electric heating device is protected from harmful exhaust gases from the non-electric heating device, thereby enabling reliable long-term operation of the hybrid heating system.

[0078] The present invention also relates, in consideration of the above-mentioned properties or advantages, to the use of the system according to the present invention to reduce and / or avoid the formation of climate-adverse emissions such as carbon oxides in process heat generation in the operation of heat-consuming processes, preferably coating processes such as zinc plating, and in particular hot-dip galvanizing.

[0079] Accordingly, the present invention also relates to the use of the system according to the present invention for extracting excess current when current peaks occur and / or for improving the usefulness of grids in heat consumption processes, preferably coating processes such as zinc plating, and especially hot-dip galvanizing.

[0080] It is understood that the system according to the present invention can also be used in combination with the above-mentioned utilization aspects to reduce and / or avoid the formation of climate-detrimental emissions such as carbon oxides, and to extract surplus power during current peaks and / or improve grid utility. As described above, these utilizations relate to the collaborative or synergistic aspects of decarbonization. This is because, by using surplus power to operate electric heating devices, the proportion of non-electric heating devices can be reduced first. Furthermore, by using surplus power supplied primarily or exclusively from renewable energy sources, further decarbonization or improved sustainability can be achieved.

[0081] Therefore, such uses or aspects should preferably be understood in combination that is in line with their purpose.

[0082] Further features, advantages, and possible applications of the present invention are evident from the following description of embodiments with reference to the drawings, and from the drawings themselves. All features described and / or illustrated, individually or in any combination, constitute the object of the present invention, whether in summary in the claims or in their interrelationships. [Brief explanation of the drawing]

[0083] [Figure 1]A schematic diagram shows the sequence of the system and method according to the present invention. [Figure 2] A perspective view of the molten material contained in the tank is shown to schematically illustrate the hybrid heating process in the sense of the method or system according to the present invention. [Modes for carrying out the invention]

[0084] Figure 1 schematically shows System 1 according to the present invention for the operation and / or decarbonization of an industrial production process using molten material 2.

[0085] The components or apparatus of System 1 according to the present invention will be described below, and then the flow of the method according to the present invention using System 1 according to the present invention will be described based on these components or apparatus.

[0086] In this context, it should be noted that the following description of System 1 according to the present invention does not represent the only possibility for carrying out the method according to the present invention. Rather, the basic concepts or possible implementations described here are for actually implementing the method according to the present invention for the operation and / or decarbonization of industrial production processes using heated molten material 2. Based on this, a number of technical modifications and / or specifications are possible in principle compared with System 1 according to the present invention as described.

[0087] Since the system 1 according to the present invention is designed to operate an industrial production process using a molten material 2, the system 1 according to the present invention has a tank 3 that can contain or will contain the molten material 2 to be heated.

[0088] The molten material 2 is preferably designed as an immersion bath, particularly a zinc plating bath, or used in a metal coating process such as zinc plating, especially hot-dip galvanizing. Thus, the heated molten material 2 is provided and / or stored as a coating material.

[0089] To heat the molten material 2, the system 1 has at least one non-electric heating device 4, and preferably a plurality of non-electric heating devices 4. The non-electric heating devices 4 are preferably designed to burn a fuel gas or as gas burners to enable the introduction of heat into the molten material 2 to be heated.

[0090] Therefore, the non-electric heating device 4 is connected to an energy source 5, preferably a gas source. The energy source 5 can make available a fuel gas, such as natural gas, particularly natural gas mixed with hydrogen or pure hydrogen, for the operation of the non-electric heating device 4.

[0091] When a mixed gas is used, a hydrogen source may be provided further upstream to mix the gas generated from energy source 5, preferably natural gas, with a further gaseous component, hydrogen, or vice versa, to mix hydrogen with the gas. The hydrogen is preferably generated from a renewable energy source and produced by the electrolysis of water, in which water is broken down into hydrogen and oxygen using renewable electricity. In this respect, it is preferably so-called "green hydrogen".

[0092] To additionally or optionally heat the molten material 2, the system 1 has at least one electric heating device 6, preferably multiple electric heating devices 6.

[0093] Therefore, the electric heating device 6 can be connected to the 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 that is produced at least in part from renewable energy and supplied to the power grid 7 as needed.

[0094] The system 1 according to the present invention has a control and / or adjustment device 8 for selectively heating the molten material 2 by a non-electric heating device 4 and / or an electric heating device 6.

[0095] The control and / or regulating device 8 is designed to extract at least a portion of the surplus current in the power grid 7 and to operate the electric heating device 6 with the extracted surplus current.

[0096] Preferably for automatic and / or frequency or internet-controlled detection of excess current, the control and / or regulating device 8 includes a detection device 9 for detecting the occurrence of excess current and a control and / or regulating device 10 for operating the electric heating device 6 and non-electric heating device 4 after excess current has been detected. The detection device 9 is also understood to be a device used to receive signals transmitted by the power grid operator or a third party, thereby automatically transmitting signals when there is a current peak or excess current in the grid, or when such is notified. This type of signal is automatically generated and transmitted by the power grid operator or a third party.

[0097] The detection device 9 and the control and / or adjustment device 10 are preferably connected to each other by signals.

[0098] Preferably, this signal connection is configured such that when an excess current is generated and / or detected by the detection device 9, the control and / or adjustment device 10 is activated to draw excess current from the power grid 7.

[0099] The control and / or adjustment device 10 is designed to control or adjust the non-electric heating device 4 and the electric heating device 6. For this purpose, the control and / or adjustment device 10 is connected to the non-electric heating device 4 and the electric heating device 6 by signals.

[0100] The control and / or regulating device 10 is designed to adjust the thermal energy introduced into the molten material 2 by the non-electric heating device 4 and the electric heating device 6 as a function of the surplus current generated in the power grid 7 and / or the temperature of the molten material 2. Preferably, the regulating or controlling is done so that a constant thermal input is generated into the molten material 2 throughout the generation of the surplus current and / or so that a constant, defined process temperature of the molten material 2 is ensured.

[0101] For this purpose, the control and / or adjustment device 10 is designed to increase the power of the electric heating device 6 when excess current is generated and / or detected, preferably at the same time decreasing the power of the non-electric heating device 4, so that the total heat input or associated process temperature combined with the molten material 2 by the combination of the non-electric heating device 4 and the electric heating device 6 is kept constant. If the excess current fluctuates, the control and / or adjustment device 10 is also designed to adjust the heat input introduced into the molten material 2 by the heating devices 4, 6 so that a constant heat input or a constant process temperature can be ensured even if the excess current fluctuates.

[0102] To control or adjust the heating devices 4 and 6, the process temperature in the molten material 2 is preferably continuously measured as a control variable and compared with a reference variable or a desired process temperature of the molten material 2. Based on any possible control deviations, the power input to the heating devices 4 and 6 is then adjusted by the control and / or adjustment device 10. In principle, it is also possible to overheat the molten material 2 with the electric heating device 6 to a temperature range up to 20°C higher than the normal process temperature, and then temporarily adjust the electric heating until the temperature of the molten material 2 returns to the normal process temperature. The control and / or adjustment device 10 is also designed to completely shut down the non-electric heating device 4 or to heat the molten material 2 by the electric heating device 6 alone. The molten material 2 is then preferably heated by the electric heating device 6 alone or using only excess current.

[0103] However, the molten material 2 can also be heated by operating only the non-electric heating device 4 via the control and / or adjustment device 10, in which case the control and / or adjustment device 10 is designed to completely shut down the electric heating device 6.

[0104] It should be noted that System 1 may have additional or second (not shown) control and / or regulating devices in addition to the control and / or regulating device 8 described or illustrated. These additional or second control and / or regulating devices may be provided, in particular, for operating the process when no surplus current is present and / or designed to operate the process or the non-electric heating device 4 and / or electric heating device 6 independently of the power grid 7. Therefore, the described or first control and / or regulating device 8 is used only when surplus current is present or detected in the power grid 7.

[0105] Similarly, at least one switching device may be provided for switching between the non-electric heating device 4 and the electric heating device 6. This switching device is preferably also connected by signal to a control and / or adjustment device 8 or control and / or adjustment device 10.

[0106] Therefore, the molten material 2 is optionally heated by the electric heating device 6 and / or the non-electric heating device 4.

[0107] The term "optional" ultimately defines three different process modes, in which heating is performed by the non-electric heating device 4 alone (first process mode), by both the non-electric heating device 4 and the electric heating device 6 (second process mode), or by the electric heating device 4 alone (third process mode).

[0108] To control and / or adjust the heating devices 4 and 6, and / or change the process mode, the heating devices 4 and 6 are connected by signals to the control and / or adjustment device 8 of System 1.

[0109] The heating devices 4 and 6 are controlled via a control and / or adjustment device 8, in particular, so that a predetermined process temperature or temperature interval of the molten material 2 is specified as a target or control variable. For this purpose, the control and / or adjustment device 8 is preferably supplied with the actual temperature of the molten material 2, either continuously or intermittently, and based on this, the heating devices 4 and 6 are selectively controlled to continuously supply the molten material 2 at the predetermined process temperature.

[0110] It is understood that System 1 according to the present invention may have a temperature sensor or thermocouple (not shown) in the tank 3 and / or in the area of ​​the molten material 2 in order to determine the actual temperature of the molten material 2.

[0111] By combining heating with the non-electric heating device 4 and the electric heating device 6, decarbonization can be achieved compared to a process operated with only the non-electric heating device 4.

[0112] With this in mind, the method according to the present invention using System 1 according to the present invention will be described below.

[0113] According to this method, if a surplus current is generated in the power grid 7, it is assumed that at least a portion of the surplus current will be taken from the power grid 7 and used to operate the electric heating device 6.

[0114] The presence of excess current is preferably automatically detected by the detection device 9, and as a result, the heating devices 4 and 6 are adjusted or controlled taking into account the extracted excess current.

[0115] Specifically, the control and / or adjustment device 8 and the control and / or adjustment device 10 are designed to first use surplus current drawn from the power grid 7 to operate the electric heating device 6.

[0116] Simultaneously, or alternatively, the control and / or adjustment device 10 is also designed to reduce or stop the heating output of the non-electric heating device 4 as a result of the surplus current generated and the heating operation taken over by the electric heating device 6.

[0117] The control of the heating devices 4 and 6, particularly the starting of the electric heating device 6 and the stopping of the non-electric heating device 4, continues under the condition that a predetermined process temperature of the molten material 2 is maintained, which continues to be processed as a reference variable or target variable in the control and / or adjustment device 8 or the control and / or adjustment device 10.

[0118] Before any excess current is detected, it is first confirmed that the molten material 2 is effectively heated only by the non-electric heating device 4, which is operated or supplied by the energy source 6. When an excess current is detected from the power supply 7, the electric heating device 6 is activated, and as a result, the heat input that was previously provided only by the non-electric heating device 4 is partially or completely taken over by the electric heating device 6.

[0119] As a result, exhaust gas pollution emitted from the non-electric heating device 4 is reduced, and the decarbonization of the industrial production process achieved by the process is promoted.

[0120] At the same time, the use of surplus power is related to improving the grid efficiency of the power grid 7. This is because it avoids or compensates for the overload of the power grid 7 that could occur if the surplus power were not used.

[0121] In particular, in cases of prolonged periods or excessive surplus current, it has been confirmed that completely stopping heating by the non-electric heating device 4 and heating the molten material 2 solely by the electric heating device 6 is effective.

[0122] Possible embodiments of the arrangement and / or design of heating devices 4 and 6 for heating the molten material 2 held in tank 3 will be described below with reference to Figure 2.

[0123] In this context, it should be noted that the illustrated arrangement is a possible technical modification of the present invention for carrying out the method according to the present invention, but should not be understood as necessarily or exclusively technical. In this regard, the teachings of the present invention are not limited to the arrangement shown below, and numerous other embodiments are possible or conceivable.

[0124] The connection and / or design of the heating devices 4 and 6 for heating the molten material 2 is preferably such that process control can be performed throughout the entire process time, or using the non-electric heating device 4 or the electric heating device 6 independently of each other, or using only one of them. This also makes it possible to use the heating devices 4 and 6 in combination so that the thermal coupling introduced by the heating devices 4 and 6 is in any ratio.

[0125] In particular, the electric heating device 6 is designed and / or configured to heat the molten material 2 to a predetermined process temperature range solely by electric heating, preferably using only surplus current from the power grid 7.

[0126] The embodiment shown in Figure 2 includes a furnace chamber 11 that at least partially encloses the tank 3, which is preferably designed as an annular chamber and / or encloses the tank 3 from all directions.

[0127] The furnace chamber 11 is separated on the inside by the wall of the tank 3 and on the outside by the furnace housing 12, with the tank 3 housed in the furnace housing 12.

[0128] In the illustrated preferred embodiment, a plurality of rod-shaped electric heating devices 6 are provided, which are inserted into or immersed in the molten material 2 for direct contact or heating. The electric heating devices 6 can be positioned inside the molten material 2, preferably in pairs with opposing end faces of the tank 3, and particularly perpendicular to the surface during use.

[0129] Furthermore, a plurality of non-electric heating devices 4 are provided, which are designed as gas burners. The non-electric heating devices 4 are designed to heat the furnace chamber 11 and / or are located on or within the furnace chamber 11, preferably in the area of ​​at least one side wall of the tank 3, particularly the longitudinal side wall. However, the non-electric heating devices 4 and / or electric heating devices 6 may be located on opposing side walls of the tank 3, particularly the longitudinal side walls.

[0130] The non-electric heating device 4 may be provided on or within the furnace housing 12, preferably positioned and / or housed in the region of at least one side wall of the furnace housing 12, particularly the longitudinal side wall.

[0131] In addition to, or as an alternative to, the electric heating device 6 placed in the molten material 2, at least one electric heating device 6 may be placed in the furnace chamber 11. The electric heating device 6 may preferably be designed as an electrical and / or flexible heating conductor, the length of which the electrical conductor is several times greater than the length of the tank 3.

[0132] The electric heating device 6 is preferably located on the same side wall of the tank 3 as the non-electric heating device 4, particularly on the longitudinal side wall.

[0133] In the illustrated preferred embodiment, the electric heating device 6 is arranged in a loop or meandering manner around the non-electric heating device 4, preferably so that the non-electric heating device 4 is surrounded by the electric heating device 6.

[0134] It is understood that other arrangements may be adopted for the non-electric heating device 4 or the electric heating device 6.

[0135] In embodiments not shown, all or at least some of the non-electric heating devices 4 or heating burners may be configured to be isolated from the tank 3 or furnace chamber 11 and / or located in an upstream heating chamber of the tank 3. This heating chamber functions as an upstream heating chamber to which heated heating air or heated heating gas is supplied. In contrast, the electric heating devices 6 are isolated from the non-electric heating devices 4 and are directly immersed in the molten material 2 and / or located within the furnace chamber 11.

[0136] Alternatively or additionally, all or at least some of the electric heating devices 6 may be arranged to be isolated from the tank 3 or furnace chamber 11 and / or located in an additional heating chamber or an upstream heating chamber of the tank 3. This one or more heating chamber functions as an upstream heating chamber to which heated heating air or heated heating gas is supplied. In contrast, the non-electric heating devices 4 are designed to heat the furnace chamber 11 and / or are located separately from the electric heating devices 6.

[0137] By storing heated air in the upstream heating chamber, preferably starting with the electric heating of the molten material 2, this heated air can be supplied to the furnace chamber 11 with a rapid response time when the heating of the molten material 2 is switched to a non-electric heating device 4. For this purpose, the furnace chamber 11 may be filled with heated air to ensure the continuation of production or the maintenance of a predetermined process temperature of the molten material 2. For this purpose, the furnace housing 12 may have corresponding inlet and / or outlet lines 13 for supplying heated heat flow or heated air to the furnace chamber 11 as needed and / or for discharging used process air from the furnace chamber 11.

[0138] At least one electric heating device 6 and / or at least one non-electric heating device 4 are placed in the furnace chamber 11, and the indirect thermal coupling by these is carried out such that the air in the furnace chamber 11 is heated in particular through the side walls, especially the longitudinal side walls, and the walls of the tank 3 located above it are heated. As a result, the molten material 2 is first heated on the wall side. Due to the resulting thermal convection, a flow or circulation of the molten material 2 heated on the wall side is created inside the tank 3, and the heated molten material 2 that started from the wall portion also reaches the inside of the tank 3, and thus the heated molten material 2 is mixed inside the tank 3.

[0139] It is preferable that the electric heating device 6 is specially isolated or protected from harsh exhaust gases from the non-electric heating device 4, especially when the heating devices 4 and 6 are arranged or housed together within the furnace chamber 11.

[0140] The inlet and / or outlet 13 may preferably be closed as needed, and / or a corresponding exhaust gas flap may be provided.

[0141] Furthermore, several thermocouples or sensors are preferably attached to the tank 3 to continuously monitor and / or record the temperature of the molten material 2 and / or the heating temperature inside the furnace chamber 11.

[0142] Therefore, the temperature in the tank 3 and / or furnace chamber 11 functions as a control variable and is supplied to the control and / or adjustment device 8, or control and / or adjustment device 10, for the purpose of adjusting the non-electric heating device 4 and the electric heating device 6 accordingly. As a result, the heat input to the electric heating device 6 and / or non-electric heating device 4 is adjusted or regulated as necessary to avoid the critical temperature of the system and / or to maintain the molten material 2 permanently at a predetermined process temperature.

[0143] The control and / or adjustment device 8 may have a switching device to switch heating modes between the electric heating device 4 and the non-electric heating device 6 as needed. The switching device may have corresponding switching and / or line components for this purpose.

[0144] The non-electric heating devices 4 are preferably arranged within the furnace chamber 11 as a matrix and / or in a fixed group pattern. Preferably, the non-electric heating devices 4 are associated with the side walls of the tank 3, particularly the longitudinal side walls.

[0145] Alternatively or additionally, non-electric heating devices 4 and / or electric heating devices 6 can be assigned to opposing side walls of the tank 3, particularly the longitudinal side walls.

[0146] For a predetermined thermal coupling, the non-electric heating device 4 and / or electric heating device 6 can be controlled or adjusted individually or in predetermined zones or groups, in particular by control and / or adjustment device 8 and / or control and / or adjustment device 10.

[0147] If the control and / or adjustment device 8, in particular the detection device 9, receives a pulse from the power grid 7, in particular by frequency or internet control, indicating that there is a surplus current in the power grid 7, the thermal or combustion output of the non-electric heating devices 4 is reduced by turning off one or more non-electric heating devices 4 and / or reducing the thermal or combustion output of one or more non-electric heating devices 4. At the same time, electric heating is started via the electric heating device 6 using the surplus current supplied from the power grid 7.

[0148] For this purpose, the non-electric heating mode can be completely shut off after a predetermined transition period as needed, thereby preventing heat from being combined through the non-electric heating device 4. The molten material 2 is then heated only through the electric heating device 6, which is preferably housed within the molten material 2. The entire molten material 2 is heated by convection and mixing within the tank 3, or uniformly heated by the electric heating device 6.

[0149] The molten material 2 can be heated via the electric heating device 6 to a temperature higher than the process temperature or a predetermined process temperature interval, preferably at least 20°C higher than the process temperature, and preferably at least 40°C higher. After this overheating, the heating can be reduced or stopped completely by the non-electric heating device 4 and / or the electric heating device 6, so that the molten material 2 cools again from a state where it has been overheated above the process temperature. If the molten material 2 has reached or fallen below the process temperature again, the molten material 2 can be reheated by the non-electric heating device 4 and / or the electric heating device 6, preferably by the electric heating device 6 alone, preferably so that the molten material 2 is again heated above the process temperature.

[0150] In this regard, a heating interval can be defined during which the molten material 2 is not heated. During this heating interval, the molten material 2 is preferably reheated only by the electric heating device 6.

[0151] The heating interval can be flexibly set, preferably so that the coating process can be operated continuously both within and between heating intervals. [Explanation of symbols]

[0152] 1 System 2. Molten material 3 tanks 4 Non-electric heating devices 5. Energy sources 6. Electric heating device 7 Power grid 8. Control and / or adjustment devices 9. Detection device 10 Control and / or adjustment device 11 Furnace room 12 Furnace Housing 13 Entrances and / or exits

Claims

1. In particular, a method for operating and / or decarbonizing industrial production processes, preferably coating processes such as zinc plating, wherein a heated molten material (2) is provided and / or maintained. The heating of the molten material (2) is performed by at least one electric heating device (6) and / or at least one non-electric heating device (4). A method wherein, when a surplus current is generated in the power grid (7), this surplus current is drawn out from the power grid (7) at least partially and used to operate the electric heating device (6).

2. The method according to claim 1, characterized in that the generation of the excess current is detected by a detection device (9), the electric heating device (6) and the non-electric heating device (4) are operated by a control and / or adjustment device (10) after the detection of the excess current, and preferably the molten material (2) is provided and / or maintained within a predetermined process temperature range using the excess current.

3. The method according to claim 1 or 2, characterized in that the production process is carried out continuously during electric heating (6), particularly within a predetermined temperature range.

4. The method according to any one of the preceding claims, characterized in that when the excess current is generated and / or detected, the heating power of the non-electric heating device (4) is reduced, the operation of the electric heating device (6) is started, preferably the operation or heating by the non-electric heating device (4) is terminated, and the heating of the molten material (2) is performed solely by the electric heating device (6) using the excess current.

5. The method according to any one of the preceding claims, characterized in that the heating of the molten material (2) before the generation and / or detection of the excess current is preferably performed by the non-electric heating device (4) alone, and when the excess current is generated and / or detected, the electric heating device (6) is activated in addition to the non-electric heating device (4).

6. The method according to any one of the preceding claims, wherein the non-electric heating device (4) is preferably operated exclusively with hydrogen, or a hydrogen-containing fuel gas and / or mixed gas, particularly a hydrogen-natural gas mixed gas, as a fuel gas, and preferably the fuel gas and / or mixed gas contains at least 1 to 80 volume%, preferably 25 to 90 volume%, and preferably 50 to 100 volume%, of hydrogen.

7. The method according to any one of the preceding claims, characterized in that the molten material (2) is heated at least partially indirectly through a tank (3) containing the molten material (2), preferably a furnace chamber (11) surrounding the tank (3) is heated by the electric heating device and / or the non-electric heating device (4, 6), in particular the furnace chamber (11) is heated by the non-electric heating device (4), and the molten material (2) is further heated, preferably by direct and / or contact bonding, by the electric heating device (6) positioned within the molten material (2).

8. The molten material (2) is maintained at a process temperature at least 10°C, preferably at least 20°C, and particularly at least 30°C higher than the melting point of the molten material (2); and / or The method according to any one of the preceding claims, characterized in that the molten material (2) is maintained 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. The method according to any one of the preceding claims, characterized in that the production process is carried out as hot-dip galvanizing, particularly as individual piece galvanizing, and / or the molten material (2) is provided and / or maintained as a zinc alloy.

10. A system (1) for operating and / or decarbonizing a preferably industrial production process, preferably a coating process such as zinc plating, using a molten material (2), and more particularly a system for carrying out the method according to any one of the preceding claims, A tank (3) for the molten material (2) to be heated, At least one electric heating device (6) and at least one non-electric heating device (4), A system comprising at least one control and / or adjustment device (8) for selectively heating the molten material (2) by the electric heating device (6) and / or the non-electric heating device (4), wherein the control and / or adjustment device (8) is additionally configured to draw at least a portion of the surplus current generated in the power grid (7) and to operate the electric heating device (6) with the drawn surplus current.

11. The system according to claim 10, wherein the control and / or adjustment device (8) includes a detection device (9) for detecting the generation of the excess current and a control and / or adjustment device (10) for operating the electric heating device (6) and the non-electric heating device (4) after the detection of the excess current, and in particular, after detection, the molten material (2) is provided and / or maintained within a predetermined process temperature range.

12. The system according to claim 10 or 11, wherein a furnace chamber (11) is provided that at least partially surrounds the tank (3), and preferably the electric heating device (6) and / or the non-electric heating device (4) are arranged in the furnace chamber (11), in particular the non-electric heating device (4) being arranged in the furnace chamber (11), and the electric heating device (6) being arranged to come into contact with the molten material (2) and / or to directly heat the molten material (2) inside the tank (3).

13. Use of the system according to any one of the preceding claims for decarbonization, in particular for reducing and / or avoiding the formation of climate-adverse emissions such as carbon oxides, in the operation of a heat consumption process, preferably a coating process such as zinc plating.

14. Use of the system according to any one of the preceding claims, particularly claim 12, to draw out excess current when a current peak occurs and / or to improve the maintainability of the grid in a heat dissipation process, preferably a coating process such as zinc plating.

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