Method for using excess current occurring in a power network and system for operating a preferably industrial process

Abstract

The present invention relates to a method for using excess current occurring in a power network (5), wherein at least some of the excess current is taken from the power network (5) and at least one melt (2), in particular a metal melt, is thermally charged and / or heated by the taken excess current, and wherein the heated melt (2) is kept and / or provided as an electrical heat store and for processing in an industrial production process, preferably a coating process, such as galvanisation, in particular hot-dip galvanisation.

Description

[0001] Method for using surplus electricity generated in a power grid and plant for operating a preferably industrial process

[0002] The invention relates to a method for utilizing surplus electricity generated in a power grid. Furthermore, the present invention also relates to a system for operating a preferably industrial process or production process using a melt and, preferably, a treatment bath upstream or downstream of the melt, preferably in a hot-dip galvanizing process for iron or steel components with upstream flux treatment. Finally, the present invention also relates to the use of a preferably metallic melt and / or a treatment bath, preferably a flux bath, as a heat and / or buffer storage device.

[0003] The present invention relates to the operation of industrial processes in which the production, 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 change the 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 is specifically aimed at heat-consuming industrial production or processing processes that take place with the provision and / or use of a heated melt or in which a heated melt is provided and / or kept in stock. Heated melts are preferably understood to mean liquid metal of any type and, if necessary, any alloy, which is used in a variety of ways in industrial production processes, for example in the casting or coating of workpieces. The primary starting point of the invention, however, are industrial 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 accordingly kept or made available.

[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] The high energy demand, especially in hot-dip galvanizing, is primarily due to the fact that the zinc melt stored or provided for coating must be maintained at a defined process temperature continuously 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] From the perspective of the transformation to a climate-neutral industry, this inevitably entails corresponding challenges, especially since the process heat requirement in production processes of the type mentioned above, particularly in galvanizing, is in practice met by the combustion of fossil fuels, mostly gas, such as natural gas.

[0009] These challenges are particularly significant in industrial production processes using melts, since the associated, comparatively complex process management and the requirement for continuous and defined heating of the melt, according to common opinion, require the combustion of fossil fuels, such as natural gas, to ensure sufficient heat input and thus reliable heating of the melt. In this respect, and also 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. The object of the present invention is to avoid the aforementioned disadvantages of the prior art or at least to substantially reduce them.

[0010] According to the invention, in order to achieve the above-mentioned object, a method for utilizing surplus electricity accumulating in a power grid is proposed, wherein the surplus electricity is at least partially withdrawn from the power grid and at least one melt, in particular a metal melt, is thermally charged and / or heated by the withdrawn surplus electricity, and wherein the heated melt is or are kept and / or made available both as an electrical heat storage device and for processing in an industrial production process, preferably a coating process, such as galvanizing, in particular hot-dip galvanizing.

[0011] The overload current is preferably drawn from the power grid for the duration of its occurrence to heat the melt and / or thermally charge the melt. If necessary, the overload current is also used, particularly after heating and / or thermally charging the melt, to maintain heat and / or temperature, in particular to maintain the temperature, of the melt, thereby increasing the time interval for using the overload current.

[0012] In developing the present invention, it was recognized that it is a practical measure to introduce surplus electricity accumulating in a power grid into a melt and use it to at least partially cover the process heat demand in an industrial production process in which the heated melt is processed. Particularly preferably, the process heat demand and / or the charging of the melt as a thermal heat storage device is completely covered by the surplus electricity drawn from the power grid. However, it is also possible for the surplus electricity to be used to partially cover the heat demand, and for the remaining heat demand to be covered by other energy sources, for example, process heat originating from the process itself or other energy sources. "Surplus electricity" in the context of the present invention refers to excess or unused electrical energy.Excess electricity occurs primarily as a result of feed-in from renewable energies, which are only available with 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 oversupply or surplus power in the power grid. Preferably, the grid operator specifies or indicates when surplus power is present in the power grid.

[0013] In practice, attempts have been made to store surplus electricity or power peaks in storage systems such as batteries and pumped-storage power plants and later feed it back into the power grid. However, the use of traditional battery systems is problematic in terms of costs and the associated resource requirements. 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 thus not effective, especially from a sustainability perspective. The recycling or disposal of batteries on the required scale is also known to be problematic. However, the invention does not rule out the possibility of using battery systems or other systems for storing surplus electricity in addition to heating the melt using the surplus electricity.If there is no excess power available, the melt can then be heated or thermally charged using the charged battery systems. A combined charging of the melt using excess power on the one hand and discharging of battery systems on the other is also possible according to the invention.

[0014] Addressing this problem, the surplus electricity generated in a power grid is now directed to a targeted or specific industrial use based on the inventive concept. A melt is heated using the surplus electricity and stored as an electrical heat storage device for, preferably subsequent, processing in an industrial production process. As an "electrical heat storage device" or "heat battery" or as an electrically operated heater, the melt, in particular the metal melt, absorbs electrical energy in the form of the surplus electricity and stores it in the form of thermal energy or heat.

[0015] Surplus electricity, i.e. electrical energy with temporally fluctuating output, is due in particular to the proportion of renewable energies, the electricity share of which is increasingly being fed into the electricity grid on a priority basis. As the underlying energy sources, namely sun, wind and water, are not available at constant speeds and their availability is also difficult to predict, fluctuating outputs and excess capacities or periods of surplus electricity are ultimately unavoidable. For example, a short period of high wind speeds can lead to an oversupply of electricity or to power peaks in the electricity grid. This brings with it the problem that the resulting surplus electricity has to be diverted or used to avoid overloading the electricity grid and the associated damage. Even a deviation from the required grid frequency, for example from 50 Hz, can lead to overloading or peaks in the grid.This can lead to a failure and / or disruption of the power grid. To avoid excess power and endanger the stability of the power grid, renewable energy (RE) plants may be temporarily throttled or even shut down. This leads to technically and economically inefficient use of these plants. It also slows down the goals of increasing the share of RE in the electricity mix.

[0016] The concept according to the invention now creates the possibility of feeding even surplus electricity that fluctuates greatly over time into process-related use by heating the melt, since melts of the type in question have a comparatively high thermal inertia and / or change their temperature only relatively slowly when heat is added and / or removed due to a relatively high mass or heat capacity. Accordingly, a high level of surplus electricity can be absorbed, especially since the process heat demand arising in the preferably downstream industrial process is correspondingly high and a correspondingly large amount of surplus electricity can be fed into the melt for subsequent use. Accordingly, renewable energy plants can be used more efficiently and the share of renewable energy in the electricity mix can be increased. The use of surplus electricity in the sense mentioned above is based on the fundamental insight that the heating of the melt is also electrically based and / orbased on electrical heating on an industrial scale is even possible.

[0017] In industrial processes using a melt, particularly in galvanizing, the heat required has so far been met exclusively by fossil fuels, such as natural gas or other fossil gaseous energy sources. In this respect, the use of an electrically heated melt for processing in an industrial production process, particularly in a coating process such as galvanizing, represents a departure from the prevailing opinion. In particular, especially in the context of galvanizing plants, it has been deemed disproportionate to consider an energy source other than fossil fuels, as this would entail laborious conversion and conversion measures for the plants in question, especially since the heat-consuming industrial processes in question, particularly galvanizing, are characterized by comparatively complex process management.

[0018] In accordance with the inventive solution, the problem in question is initially circumvented by the fact that thermal charging of the melt using excess electricity can ultimately be carried out decoupled from the industrial process itself. Within the scope of this charging or the charging period, a process control that is simplified compared to the manufacturing process or the industrial process can be implemented, so that a simple structural implementation for coupling the excess electricity into the melt can be implemented, for example by means of an electrical heating device. This utilizes the high suitability of the melt with regard to electrical heat storage. It should be noted, however, that thermal charging of the melt can also be implemented during the production process using excess electricity, for example by means of an appropriate electrical heating device.As a result, the present invention proposes, for the first time and in the form of a self-contained concept, the targeted use of excess electricity to heat a melt, so that the heated melt functions as an electrical heat storage device and can be made available, in particular, for subsequent processing in an industrial production process. The invention thus creates the possibility of using the electrical energy originating from excess electricity for targeted use in an industrial process environment, namely for heating a melt. At the same time, the invention also contributes to ensuring a stable power grid with a preferably constant grid frequency.

[0019] Against this background, the solution according to the invention thus makes a contribution to avoiding overloading of the power grid and to an efficient and targeted industrial use of surplus electricity, which in particular comes primarily from renewable energy sources, i.e. solar, wind and hydropower.

[0020] Furthermore, the solution according to the invention also makes a contribution to the decarbonization of industrial production processes, in particular galvanizing processes, since the heating by fossil fuels, which is provided for in practice, is at least partially replaced by electrical energy or by surplus electricity, accompanied by a reduction, in particular avoidance, of climate-damaging emissions, such as carbon dioxide.

[0021] In this respect, the solution according to the invention enables improved sustainability of industrial processes in several respects, which ultimately contributes to the transformation to a climate-neutral industry.

[0022] Having considered the above fundamental considerations of the inventive solution, advantageous procedural aspects of the present invention are discussed below.

[0023] According to a preferred process, the use of the excess flow extends beyond heating the melt to at least one treatment bath upstream or downstream of the melt, in particular a flux bath upstream of the melt. In this respect, in addition to the heated melt, the heated treatment bath can also be stored and / or made available both as an electrical heat storage device and for processing in the industrial production process.

[0024] The heated treatment bath can also preferably be kept thermally warm or at least substantially constant temperature after heating by at least partially using overload current.

[0025] Flux treatment using a flux bath, also known as fluxing, is used particularly in coating processes such as galvanizing, especially hot-dip galvanizing, to perform a final, intensive, ultra-fine cleaning of the component surface before the component or steel surface reacts with the molten coating, especially zinc, and / or to dissolve the oxide layer of the zinc surface and prevent re-oxidation of the component surface, especially the steel surface, until the coating or galvanizing process. Furthermore, the flux bath increases the wettability between the component surface and the coating bath or the molten zinc.

[0026] In this respect, the treatment bath represents a further heat-consuming process step within the meaning of the industrial production process in question. It is particularly expedient to use the surplus electricity in question to cover the heat energy required in this regard, so that the heated treatment bath is also kept and / or made available as an electrical heat storage device for processing in the industrial production process.

[0027] According to a particularly preferred method, thermal energy is at least partially extracted from the heated melt and / or the heated treatment bath and converted into electrical current by means of at least one conversion device, preferably with the converted electrical current being fed back into the power grid. Accordingly, a so-called "bidirectional" or opposite-direction energy conversion is provided, whereby, in addition to the extraction of excess current for heating the metallic melt or the treatment bath, excess heat from the melt or the treatment bath is also fed back into electrical energy.

[0028] The conversion of thermal energy into electrical power can be achieved in a variety of ways, for example, according to the principle of "thermo-photovoltaics," in which special thermo-photovoltaic cells act as absorbers and, with band gaps in the infrared range, can convert thermal radiation into electrical power. In principle, however, a variety of technical implementations are possible for converting thermal radiation or thermal energy into electrical energy.

[0029] By feeding back or converting thermal energy into electrical power, a further increase in the efficiency of the process according to the invention is achieved by preventing excess thermal energy from being released unused into the environment, but rather converting it back into electrical energy with comparatively little loss and feeding it back into the power grid for further use.

[0030] In particular, the invention provides that the heating of the melt and / or the treatment bath and / or the heat extraction from the melt and / or from the treatment bath is upstream or downstream of the production process and / or is decoupled from the production process.

[0031] The decoupling is expediently achieved by providing an upstream thermal "charging period" that is decoupled from the "production process," whereby an increased proportion of surplus electricity in the power grid is to be expected during the charging period. Particularly in the case of surplus electricity generated by solar energy, it may be expedient to carry out charging during the day when there is correspondingly high excess capacity, in order to initially thermally charge the melt and, preferably, the treatment bath upstream of production using particularly strong surplus electricity. If there is no surplus electricity in the power grid, charging can be stopped or suspended. Alternatively, however, a discharge of any battery systems or other storage systems provided can be provided in order to continue charging even when there is no surplus electricity. The industrial production process using the charged orThe heated melt or the charged and / or heated treatment bath can be charged when there is a reduced surplus power in the power grid compared to the charging period, for example with regard to surplus power caused by solar energy at night or when there is reduced solar radiation.

[0032] In particular, in this context, it can be provided that the heating of the melt and / or the treatment bath for charging with excess current takes place at least temporarily in a charging period between 10:00 a.m. and 4:00 p.m., preferably 9:00 a.m. to 5:00 p.m. and in particular between 6:00 a.m. to 6:00 p.m. and / or that the production process takes place outside the charging period.

[0033] However, it is understood that an overlap of the charging period and the production process is also possible, whereby the charging or heating of the melt and / or the treatment bath takes place using excess electricity during the operation of the industrial production process or the coating process, in particular galvanizing and / or hot-dip galvanizing. In this configuration, a combined method is thus implemented for utilizing excess electricity generated in a power grid and for operating an industrial process using a melt, preferably in a galvanizing process, such as galvanizing, preferably hot-dip galvanizing with upstream flux treatment.

[0034] In order to enable particularly efficient charging, it is preferably provided that the heating of the melt or the treatment bath and / or the heat extraction from the melt or the treatment bath takes place over a period of at least 1 hour per day, preferably 5 hours per day. In principle, however, the period for charging or discharging the melt and / or the treatment bath can be selected flexibly, since the melt or the treatment bath can be used in the long term as a buffer storage or electrical heat storage, in particular due to the comparatively low thermal inertia of the melt or the treatment bath, in particular the metallic melt. The occurrence of the excess current can be detected by a detection device and the melt and / or the treatment bath can be heated, preferably automatically, by means of at least one electrical heating device ora further electrical heating device, preferably such that the heated melt and / or the heated treatment bath is / are provided and / or maintained at a charging temperature using excess current, particularly preferably wherein the heating of the melt and / or the treatment bath takes place exclusively by the electrical heating device or the further electrical heating device using excess current. This enables simple and efficient process control, ensuring that any occurrence of excess current is reliably detected or recognized and used for thermally charging the melt and / or the treatment bath.

[0035] The detection device can be provided at a spatially decoupled location, for example assigned to a network operator.

[0036] The charging temperature at which the melt and / or the treatment bath is / are kept during the charging period exceeds the processing temperature or production temperature of the melt and / or the treatment bath present in the production process, preferably by at least 10 °C, preferably by at least 20 °C, particularly preferably by at least 50 °C.

[0037] While certain process temperature ranges must be maintained during production or the production process to ensure coating quality, the charging period, which is particularly decoupled from the production process, can be designed more flexibly in this regard. In particular, overheating of the melt and / or the treatment bath compared to the processing temperature is possible during the production process in order to utilize pronounced excess current or high current peaks for thermal charging. However, it is understood that the charging temperature can be adapted to the processing temperature of the melt or the treatment bath or can be considered technically equivalent in order to ensure charging of the melt and / or the treatment bath even during ongoing production and to avoid any loss of process or coating quality due to overheating of the melt or the treatment bath.In this constellation, the charging period and the production process run parallel to each other or overlap laterally, at least in part.

[0038] According to a particularly preferred embodiment, the charging temperature is at least 10 °C, preferably at least 20 °C, more preferably at least 30 °C, and most preferably at least 50 °C below the boiling point of the melt and / or the treatment bath. This ensures that the overheating preferably provided during the charging period will not impair the quality of the melt or the treatment bath in the subsequent process.

[0039] Specifically, it is preferably provided that the charging temperature of the melt is in the range from 390 °C to 900 °C, preferably in the range from 430 °C to 880 °C, particularly preferably in the range from 500 °C to 850 °C.

[0040] Particularly preferably, the charging temperature of the treatment bath is in the range from 60 °C to 200 °C, preferably in the range from 80 °C to 180 °C, particularly preferably in the range from 100 °C to 150 °C.

[0041] In the following, according to a further aspect of the present invention, the plant according to the invention for operating a preferably industrial process is described.

[0042] Specifically, the system comprises a vessel for the melt to be heated and, preferably, another vessel upstream or downstream of the melt for a treatment bath, in particular for a flux bath upstream of the melt. Furthermore, at least one immersion device is provided for immersing and / or removing at least one component into and / or from the melt. In particular, the immersion device is also additionally designed for immersing and / or removing the component into and / or from the treatment bath.

[0043] According to the invention, the system has at least one electrical heating device for thermally charging and / or heating the melt and, preferably, at least one further electrical heating device for thermally charging and / or heating the treatment bath, in particular wherein at least one control and / or regulating device is provided which is designed to at least partially withdraw an excess current occurring in a power grid and to operate the electrical heating device and, preferably, the further electrical heating device or to control and / or regulate them.

[0044] Accordingly, the system according to the invention is designed and constructed specifically for the device-based implementation of the previously discussed method. The advantages previously mentioned for the method also apply equally to the system.

[0045] The plant according to the invention is preferably based on a conventional coating plant or a plant known from practice, in particular a galvanizing plant, wherein, with regard to the method according to the invention, at least one electrical heating device for the melt and, preferably, at least one further electrical heating device for the treatment bath is or are provided.

[0046] With the control and / or regulation device also provided according to the invention, the excess power generated in the power grid can be extracted and the electric heating device and, preferably, the additional electric heating device can be operated. On this basis, both the charging period, which is preferably decoupled from the production process, and the production process itself can be implemented without the need for further structural adjustments or modifications to the system according to the invention during the transition from the charging period to the production process.In a further preferred embodiment of the invention, at least one conversion device is provided for at least partially converting the thermal energy of the heated melt and / or the heated treatment bath into electrical current, preferably wherein the conversion device is designed to feed the converted electrical current back into the power grid.

[0047] In view of the above special features and advantages, the present invention also relates to the use of a preferably metallic melt and / or a treatment bath, preferably a flux bath, as a heat and / or buffer storage device, wherein the melt and / or the treatment bath is / are thermally charged and / or heated by surplus electricity from a power grid and wherein the heated melt and / or the heated treatment bath is / are kept and / or made available in an industrial production process, preferably a coating process, such as galvanizing, preferably hot-dip galvanizing with upstream flux treatment.

[0048] This allows the advantages described above to be realized accordingly.

[0049] 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, form the subject matter of the present invention, regardless of their summary in the claims or their reference back to them.

[0050] It shows:

[0051] Fig. 1 is a schematic representation of a system according to the invention and the sequence of the method according to the invention during a charging period and

[0052] Fig. 2 is a schematic representation of a plant according to the invention and the sequence of the method according to the invention during a first method step in a production process,

[0053] Fig. 3 shows a further schematic representation of the system according to the invention and the sequence of the method according to the invention during a second method step in the production process and

[0054] Fig. 4 shows a further schematic representation of the system according to the invention and the sequence of the method according to the invention during a third method step in the production process.

[0055] Fig. 1 schematically shows a plant 1 according to the invention for operating an industrial production process using a melt 2.

[0056] In Fig. 1, the method according to the invention is shown during a charging period, whereas in Figs. 2 to 4 the sequence of the production process is shown, which preferably follows the charging period.

[0057] In the following, 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.

[0058] In this context, it should be noted that the processes shown and described represent a process possible according to the invention, but individual process steps can also be omitted or provided in a different order than shown and described below. Additional process steps can also be provided. Furthermore, not all process steps necessarily have to be provided in a spatially consolidated plant 1. The decentralized implementation of individual process stages is also possible. The plant 1 according to the invention has a boiler 3 for the melt 2 to be heated.

[0059] 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.

[0060] For heating the melt 2, the plant 1 has at least one electrical heating device 4, preferably a plurality of electrical heating devices 4.

[0061] The electric heating device 4 can accordingly be connected to a power grid 5. The power grid 5 is preferably a public power grid 5. Preferably, the power grid 5 or the electrical energy source provides electricity generated at least partially from renewable energy sources, which is fed into the power grid 5 as needed.

[0062] Not shown in detail is that the system 1 also has at least one non-electrical heating device, preferably for burning a fuel gas or by means of at least one gas burner, to heat the melt 2 in addition to the electrical heating device 4. The non-electrical heating device is also connected to an energy source, preferably a gas source. The energy source can provide fuel gas, for example natural gas, in particular natural gas mixed with hydrogen or pure hydrogen, to operate the non-electrical heating device.

[0063] The plant 1 according to the invention preferably has a control and / or regulating device 6 for heating the melt 2 by means of the electrical heating device 4.

[0064] The control and / or regulating device 6 is designed to at least partially extract excess power accumulating in a power grid 5 and to operate the electrical heating device 4 with the extracted excess power, particularly in combination with the non-electrical heating device. For the preferably automatic and / or frequency- or internet-controlled detection of the excess power, the control and / or regulating device 6 has a detection device 7 for detecting the occurrence of the excess power. A detection device 7 is also understood to be a device that is designed to receive signals transmitted by the grid operator or a third party, wherein the transmission of a signal occurs automatically, during power peaks or excess power is present in the grid, or when such a situation is imminent. Signals of this type are automatically generated and transmitted by the grid operator or third parties.

[0065] The detection device 7 and the control and / or regulating device 6 are preferably connected to each other by signaling.

[0066] However, a preferably signaling and / or functional decoupling of the detection device 7 from the control and / or regulating device 6 can also be provided. In particular, the detection device 7 is then assigned to a grid operator, whereby, in the event of excess power being available, the grid operator makes this available to the operator of the system 1 and feeds it to the control and / or regulating device 6 via the power grid 5.

[0067] The control and / or regulating device 6 is designed to control and / or regulate the thermal energy introduced into the melt 2 by the electrical heating device 4 and the optionally non-electrical heating device, specifically as a function of the excess current occurring in the power grid 5 and / or the temperature of the melt 2. Particularly preferably, the control or regulation is carried out in such a way that, in particular, a constant heat input into the melt 2 occurs over the entire occurrence of the excess current and / or a constant, defined charging temperature of the melt 2 is ensured. However, a variable charging temperature can also be implemented, in particular if temporally fluctuating excess current is provided by the power grid 5.For this purpose, the control and / or regulating device 6 is designed to increase the power of the electrical heating device 4 when the excess current occurs and / or is detected and, if necessary, to reduce the power of the non-electrical heating device, in particular depending on the degree of excess current occurring in the power grid 5.

[0068] This can lead to the melt 2 being overheated and / or being provided and / or maintained at a charging temperature that exceeds the processing temperature in the production process, in particular wherein the charging temperature exceeds the processing temperature by at least 10 °C.

[0069] In the preferred embodiment shown, the system 1 according to the invention has a treatment bath 8, which in this case is designed as a flux bath and is accommodated in a further vessel 9. The further vessel 9 with the treatment bath 8 is located upstream or downstream of the vessel 3 containing the melt 2 in terms of process technology.

[0070] Particularly preferably, at least one further heating device 10 is provided, which is intended for thermally charging and / or heating the treatment bath 8. The further electrical heating device 9 is preferably connected to the control and / or regulating device 6 via signaling, so that the excess current accumulating in the power grid 5 can be at least partially drawn and the electrical heating device 8 can be operated by the excess current.

[0071] Not shown is that at least one further non-electrical heating device can be provided, preferably for burning a fuel gas or designed as a gas burner, in order to implement a heat input into the treatment bath 8 to be heated, optionally in addition to the further electrical heating device 10. The further non-electrical heating device is connected to an energy source, preferably a gas source and / or to the control and / or regulating device 6, and can be operated with fuel gas, for example natural gas, in particular natural gas mixed with hydrogen or pure hydrogen.The control and / or regulation device 6 is designed to regulate and / or control the heat energy introduced into the treatment bath 8 by the further electrical heating device 10 and the optionally further non-electrical heating device, specifically as a function of the excess current occurring in the power grid 5 and / or the temperature of the treatment bath 8. Particularly preferably, the regulation or control is carried out in such a way that, in particular, a constant heat input into the treatment bath 8 occurs over the entire occurrence of the excess current and / or a constant, defined charging temperature of the treatment bath 8 is ensured. However, a variable charging temperature can also be implemented, in particular if excess current that fluctuates over time is provided by the power grid 5.

[0072] Particularly preferably, during the charging period, both the melt 2 and the treatment bath 8 are thermally charged in a temporally decoupled or overlapping manner, particularly depending on the excess current occurring in the power grid 5. Due to the comparatively high heat capacity of the melt 2 and the treatment bath 8, the process fluids in question function as efficient heat storage devices for storage in the preferably subsequent production process.

[0073] Particularly preferably, the plant 1 has at least one conversion device 11 for at least partially converting the thermal energy of the heated melt 2 into electrical current, preferably wherein the conversion device 11 is designed to feed the converted electrical current back into the power grid 5.

[0074] Thus, as illustrated in Fig. 4, the electrical current converted by the conversion device 11 can be used, at least in part, during production operation to operate the electrical heating device 4. It is also possible to fully utilize the electrical current converted by the conversion device 11 to operate the electrical heating device 4. In this case, no feed-back into the power grid occurs. However, a combined use of the electrical current converted by the conversion device 11 is also possible, namely to operate the electrical heating device 4 on the one hand and to feed back into the power grid 5 on the other.In the preferred embodiment shown, at least one further conversion device 12 is provided for at least partially converting the thermal energy of the heated treatment bath 8 into electrical current, preferably wherein the further conversion device 12 is designed to feed the converted electrical current back into the power grid 5.

[0075] The conversion or recycling of heat from the melt and / or from the treatment bath back into electrical energy by means of the conversion device 11 or 12 proves particularly useful when the overheated melt 2 or the overheated treatment bath 8 is cooled to the processing temperature, for example, prior to the immediately imminent production process. To prevent overheating of the melt 2 or the treatment bath 8, the thermal energy of the melt 2 and / or the treatment bath 8 can also be reconverted into electricity by means of the conversion device 11, 12. The unused release of thermal energy to the environment can thus be avoided.

[0076] With regard to the additional conversion device 12, it should also be noted that the electrical current converted by the additional conversion device 12 can be used at least partially to operate the additional electrical heating device 10. Complete or exclusive use of the electrical current converted by the additional conversion device 12 to operate the additional electrical heating device 10 is also possible. In this case, there is no need to feed the converted electrical current back into the power grid 5. However, a combination of feeding the converted electrical current back into the power grid 5 and operating the electrical heating device 10 using the electrical current converted by the additional conversion device 12 is also possible.

[0077] For control purposes, at least one conversion device 11, 12 can be connected to the control and / or regulating device 6. For example, the conversion can be initiated at a specific conversion temperature by means of the control and / or regulating device 6, which preferably defines a maximum temperature, so that before the melt 2 or the treatment bath 8 is heated above the respective boiling temperature or after reaching a predetermined maximum temperature value below the respective boiling temperature, the thermal charging is terminated and the reconversion to electricity is initiated using the conversion device 11, 12.

[0078] The system 1 according to the invention has at least one immersion device 13 for immersing and / or removing a component 14 into and / or from the melt 2. The immersion device 13 is also designed accordingly for immersing and / or removing the component 14 into and / or from the treatment bath 8.

[0079] In the illustrated and preferred embodiment, the immersion device

[0080] 13 for immersing and / or retrieving as well as for transporting at least one component

[0081] 14 or a group of components 14 along individual process areas. Accordingly, the immersion device 13 has a conveyor 5, preferably designed as a rail guide. A lifting and / or lowering means 17, for example a hoist rope, can be moved on the conveyor 15, for example via a trolley 16. A component 14 or a group of components 14 can be tied and / or suspended via the lifting and / or lowering means 17, for example via a hook, and can be fed in the process direction first to the treatment bath 8 and then to the melt. It is understood that a plurality of further treatment baths or treatment devices can be arranged upstream or downstream of the treatment bath 8 or the melt, wherein the immersion device 13 is also designed to feed the component 14 into these further treatment baths or treatment devices.

[0082] Having said this, the method according to the invention is described below using the system 1 according to the invention.

[0083] Fig. 1 shows the charging period for the thermal charging of the melt 2 and, preferably, the treatment bath 8. Fig. 2 schematically shows a production process upstream or downstream of the charging period, preferably downstream, using the heated melt 2 and, preferably, the heated treatment bath 8. However, it is understood that the charging period and the production process can also be implemented overlapping one another or simultaneously. According to the invention, during the charging period, if excess power occurs in the power grid 5, this power is at least partially withdrawn from the power grid 5 and used to operate the electrical heating device 4 and the further electrical heating device 10.

[0084] The presence of the excess current is detected by the detection device 7, with the result that the regulation or control of the heating devices 4, 10 preferably takes place exclusively by using the extracted excess current.

[0085] Specifically, it is provided that the control and / or regulating device 6 is designed to operate the electrical heating devices 4, 10 using the surplus power taken from the power grid 5.

[0086] This results in the melt 2 and the treatment bath 8 being heated or preheated, preferably exclusively by electricity or exclusively via the electrical heating devices 4, 10, using the excess electricity. This occurs during a charging period that preferably occurs during the day, i.e., between 6:00 a.m. and 6:00 p.m., and preferably outside of the production process.

[0087] The heating of the melt 2 or the treatment bath 8 can preferably be carried out continuously for a period of at least five hours per day. However, it is understood that, depending on the intensity of the excess current in the power grid 5, interruptions in the heating process may also occur.

[0088] The heating devices 4, 10 can in principle be controlled without requiring a defined target temperature and can be selected flexibly, in particular depending on the excess current occurring in the power grid 5. The heating of the melt 2 or the treatment bath 8 is preferably carried out in accordance with a defined charging temperature, which is processed as a reference variable or target variable in the control and / or regulating device 6. It is understood that in this regard, a temperature recording of the melt 2 and / or the treatment bath 8 is carried out, which is signal-linked to the control and / or regulating device 6. It has proven expedient to provide the melt 2 and / or the treatment bath 8 at a charging temperature.which exceeds a processing temperature of the melt 2 and / or the treatment bath 8 present in the production process, preferably by at least 10 °C, in particular by at least 20 °C, particularly preferably by at least 50 °C. In contrast to the production process, no exact specification with regard to the heating temperature of the melt 2 or the treatment bath 8 needs to be observed during the charging period, so that a corresponding overheating of the melt 3 and / or the treatment bath 8 can be implemented during the charging period and in this way even large amounts of excess current can be used for thermal charging.

[0089] The method according to the invention using the system 1 according to the invention during a production process is described below with reference to Fig. 2.

[0090] The component 14 to be coated or galvanized is connected to the dipping device 13 or to a product carrier of the dipping device 13. In this case, the product carrier is hook-shaped. It is also possible for the product carrier to have a basket, a rack, or the like into which the component 14 or a group of components 14 can be inserted.

[0091] As shown in Fig. 3, the component 14 is then fed to the treatment bath 8, in particular, the component 14 is subjected to a flux treatment in the treatment bath 8. The flux treatment takes place in an aqueous flux solution.

[0092] The treatment bath 8 has preferably been heated during the upstream charging period. However, it is understood that the treatment bath 8 can also be heated at least partially during the production process using excess power drawn from the power grid 5, preferably by means of the electrical heating device 10. The control and / or regulating device 6 ensures that the treatment bath 8 is regulated to a defined processing temperature with at least partial use of the excess power. It should be noted that further upstream process steps can also be carried out prior to the flux treatment, in particular a rinsing step and / or a pickling step. Preferably, degreasing of the components can also be implemented, for example using an alkaline or other degreasing agent, in order to remove residues of grease and oil on the component 14.

[0093] After a sufficient residence time in the treatment bath 8, the component 14 is conveyed to a drying furnace 18 by means of the conveying means 15 of the dipping device 13 to create a solid treatment film or flux film on the surface of the component 14 and to remove any adhering water. The drying prior to the melt treatment is important to ensure an efficient downstream coating process using the melt 2.

[0094] After drying in the drying oven 18, the component 14 is immersed in the melt 2 by means of the immersion device 13 or the conveying means 15 and is thereby subjected to a coating treatment, preferably hot-dip galvanizing.

[0095] It should be noted, and not shown in detail, that the drying oven 18 can also be operated using excess power drawn from the power grid 5. For this purpose, a heating device, preferably an electric heating device, can be provided, which in turn is connected to the control and / or regulating device 6 in order to electrically charge the drying oven 18 at least partially by utilizing excess power generated from the power grid 5.

[0096] The melt 2, as a heated heat storage device, has been charged during the charging period using the excess power drawn from the power grid 5. During the production process, the control and / or regulating device 6 ensures that the melt 2 is maintained at a defined processing temperature. During the production process, the melt 2 can also be heated, at least partially, using the electrical heating device 4 and excess power drawn from the power grid 5. After the coating treatment of the component 14 or the galvanizing, the component 14 can be quenched in a subsequent step. Quenching can also be followed by a post-treatment, which can be, for example, passivation, sealing, or an organic or inorganic coating of the coated or galvanized component 14.However, the post-treatment also includes any subsequent processing of component 14 that may be required.

[0097] The production process, in particular the galvanizing, is preferably carried out using the heated melt 2 and, in particular, the heated treatment bath 8, which have been charged accordingly during the upstream charging using the excess current.

[0098] It is understood, however, that the charging and the production by means of the system 1 according to the invention can be implemented at least temporarily in an overlapping or parallel manner, wherein the melt 2 and / or the treatment bath 8 are at least partially heated by means of excess current during or during the ongoing production process.

[0099] In this respect, the melt 2 and / or the treatment bath 8 can also function as heat and / or buffer storage during the ongoing production process, which are continuously and / or discontinuously charged accordingly by surplus power from the power grid 5 and regulated to a defined processing temperature during the ongoing production process.

[0100] List of reference symbols:

[0101] Attachment

[0102] melt

[0103] Boiler electric heating device

[0104] power grid

[0105] Control and / or regulation device

[0106] Detection device

[0107] Treatment bath additional boiler additional heating device

[0108] Conversion facility further conversion facility

[0109] Diving facility

[0110] component

[0111] Funding

[0112] trolley

[0113] Lifting and / or lowering equipment

[0114] drying oven

Claims

Patent claims:

1. Method for using energy generated in an electricity network (5) Surplus electricity, wherein the surplus electricity is at least partially taken from the power grid (5) and at least one melt (2), in particular a Metal melt is thermally charged and / or heated by the withdrawn excess current and wherein the heated melt (2) is kept and / or provided both as an electrical heat storage device and for processing in an industrial production process, preferably a coating process, such as galvanizing, in particular hot-dip galvanizing.

2. Method according to claim 1, characterized in that at least one treatment bath (8) upstream or downstream of the melt (2), in particular a flux bath upstream of the melt (2), is thermally charged and / or heated by the withdrawn excess current, in particular wherein the heated treatment bath (8) is kept and / or made available both as an electrical heat storage device and for processing in the industrial production process.

3. Method according to claim 1 or 2, characterized in that thermal energy of the heated melt (2) and / or the heated treatment bath (8) is at least partially extracted again and converted into electrical current by means of at least one conversion device (11, 12), preferably wherein the converted electrical current is fed back into the power grid (5).

4. Method according to one of the preceding claims, characterized in that the heating of the melt (2) and / or the treatment bath (8) and / or the heat extraction from the melt (2) and / or from the treatment bath (8) is carried out upstream or downstream of the production process and / or is decoupled from the production process.

5. Method according to one of the preceding claims, characterized in that the heating of the melt (2) and / or the treatment bath (8) for charging with excess current takes place at least temporarily in a charging period between 10:00 a.m. and 4:00 p.m., preferably 9:00 a.m. to 5:00 p.m. and in particular between 6:00 a.m. to 6:00 p.m., in particular wherein the production process takes place outside the charging period and / or decoupled from the charging period.

6. Method according to one of the preceding claims, characterized in that the heating of the melt (2) and / or the treatment bath (8) and / or the heat removal from the melt (2) and / or from the treatment bath (8) takes place over a period of at least 1 hour per day, preferably at least 5 hours per day.

7. Method according to one of the preceding claims, characterized in that the occurrence of the excess current is detected by a detection device (7) and the melt (2) and / or the treatment bath (8) is / are heated preferably automatically by means of at least one electrical heating device (4) and / or a further electrical heating device (10), preferably in such a way that the heated melt (2) and / or the heated treatment bath (8) is / are provided and / or maintained at a charging temperature using excess current, particularly preferably wherein the heating of the melt (2) and / or the treatment bath (8) takes place exclusively by the electrical heating device (4) and / or the further electrical heating device (10) using excess current.

8. Method according to one of the preceding claims, characterized in that the melt (2) and / or the treatment bath (8) is / are provided and / or kept at a charging temperature which exceeds a processing temperature of the melt (2) and / or the treatment bath (8) present in the production process, preferably by at least 10 °C, in particular by at least 20 °C, particularly preferably by at least 50 °C.

9. Method according to one of the preceding claims, characterized in that the processing temperature is at least 10 °C, preferably at least 20 °C, particularly preferably at least 30 °C, very particularly preferably 50 °C, above a melting temperature of the melt (2) and / or the treatment bath (8).

10. Method according to one of the preceding claims, characterized in that the charging temperature is at least 10 °C, preferably at least 20 °C, particularly preferably at least 30 °C, very particularly preferably at least 50 °C below a boiling temperature of the melt (2) and / or the treatment bath (8).

11. Method according to one of the preceding claims, characterized in that the charging temperature of the melt (2) is in the range from 390 °C to 900 °C, preferably in the range from 430 °C to 880 °C, particularly preferably in the range from 500 °C to 850 °C, and / or that the charging temperature of the treatment bath (8) is in the range from 60 °C to 200 °C, preferably in the range from 80 °C to 180 °C, particularly preferably in the range from 100 °C to 150 °C.

12. Plant (1) for operating a preferably industrial process using a melt (2), preferably in a hot-dip galvanizing plant for iron or steel components, 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 immersion device (13) for immersing and / or removing at least one component (14) into and / or from the melt (2), with at least one electrical heating device (4) for thermally charging and / or heating the melt (2) and with at least one control and / or regulating device (6) which is designed to at least partially withdraw an excess current occurring in a power grid (5) and to operate the electrical heating device (4).

13. Plant according to claim 12, characterized in that the plant (1) has at least one further boiler (5) upstream or downstream of the melt (2) for a treatment bath (8), in particular for a flux bath upstream of the melt (2), in particular wherein at least one further electrical heating device (10) is provided for thermally charging and / or heating the treatment bath (8), particularly preferably wherein the control and / or regulating device (6) is designed to at least partially withdraw the surplus current occurring in the power grid (5) and to operate the further electrical heating device (10).

14. Plant according to claim 12 or 13, characterized in that at least one conversion device (11, 12) is provided for at least partially converting the thermal energy of the heated melt (2) and / or the heated treatment bath (8) into electrical current, preferably wherein the conversion device (11, 12) is designed to feed the converted electrical current back into the power grid (5).

15. Use of a preferably metallic melt (2) and / or a treatment bath (8), preferably a flux bath, as a heat and / or buffer storage device, wherein the melt (2) and / or the treatment bath (8) is / are thermally charged and / or heated by surplus current from a power grid (5) and wherein the heated melt (2) and / or the heated treatment bath (8) is / are kept and / or made available in an industrial production process, preferably a coating process, such as galvanizing, preferably hot-dip galvanizing with prior flux treatment.

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