Computer implemented method of dynamically operating a methanation plant and a methanation plant control unit for dynamically operating a methanation plant

Abstract

The present disclosure relates to a computer implemented method and to a methanation plant control unit for dynamically operating a methanation plant (1) for producing methane and / or methanol. A digital plant twin (50) of the methanation plant (1), is provided or accessed, which comprises a plurality of digital components (51) each representing at least one methanation plant component, and respective operating boundary conditions (52) for the plurality of digital components (51). Estimated electric energy profile (44) are received indicative of the expected available electric energy to the methanation plant (1). Further, a required methane output profile (45) is received indicative of the required methane output of the methanation plant (1). The digital plant twin (50), is configured to determine the control commands (43) for operating the methanation plant (1) using the operating boundary conditions (52), the estimated electric energy profile (44) and the required methane output profile (45).

Description

[0001] P28763PC00

[0002] 1 / 35

[0003] COMPUTER IMPLEMENTED METHOD OF DYNAMICALLY OPERATING A METHANATION PLANT AND A METHANATION PLANT CONTROL UNIT FOR DYNAMICALLY OPERATING A METHANATION PLANT

[0004] FIELD OF THE DISCLOSURE

[0005] The present disclosure relates to a computer implemented method of dynamically operating a methanation plant for producing methane and I or methanol and to a control unit, in particular a methanation plant control unit, which is configured to dynamically operate a methanation plant for producing methane and I or methanol. The computer implemented method and I or the control unit use a digital plant twin as a digital image or reflection of a real methanation plant.

[0006] BACKGROUND OF THE DISCLOSURE

[0007] Methanation plants are designed to produce methane and I or methanol as an alternative source of these products with respect to natural occurrences. Natural occurrences include e.g. gas and oil fields, which are used to extract the above mentioned products. These products comprise carbon dioxide, which is released in the atmosphere when these products are used. E.g. the burning of methane (natural gas, natural gas liquids or liquefied petroleum gas) produces heat and carbon dioxide. This carbon dioxide gathers in the earth’s atmosphere and is as greenhouse gas jointly responsible for the man-made climate change.

[0008] Nevertheless, natural gas plays a huge role in the industrial energy demand. Many industries rely on natural gas, e.g. for heat production. Further, natural gas is also used as a heat source for individual homes. Reducing the consumption of natural gas is one of P28763PC00

[0009] 2 / 35 the world population targets to reduce or mitigate the negative impacts of the man-made climate change.

[0010] A part of the solution could be to reduce the natural gas consumption or to replace it with other gases like green hydrogen. Nevertheless, the handling of hydrogen is extremely challenging and it cannot be fed into the existing gas pipeline system of countries or regions. Hydrogen would require a completely new pipeline system, which is extremely expensive.

[0011] Another option could be to use green natural gas, in particular, green methane or green methanol. Green natural gas could be defined in that is has been synthesized, in particular via the sabatier-process, using renewable energy and I or renewable base products for the synthesis. The renewable energy may be provided via solar, nuclear or wind power plants etc. and the renewable base products are e.g. provided as waste or byproducts from other processes. E.g. water may be provided from a biogas plant, and carbon dioxide may be also provided from a biogas plant and I or is extracted from the air. Further, water may also be supplied from standard water grid.

[0012] The synthesis of methane is a complex procedure, which requires a plurality of components and input products. Further, the known methanation plants need preferably a constant energy supply and product inflow for an optimized output. The problem with renewable energy, e.g. from wind and solar power plants, is that the supply is not as constant as a conventional energy source like from a coal power plant. The production of green gas therefore requires new devices and methods of controlling the methanation plant in order to dynamically operate the methanation plant for the desired methane production. This requires a completely new control approach for such a methanation plant. P28763PC00

[0013] 3 / 35

[0014] SUMMARY OF THE DISCLOSURE

[0015] It is an object of the present disclosure to provide a computer-implemented method for dynamically operating a methanation plant for producing methane and I or methanol and / or a methanation plant control device, which is configured to determine control commands for dynamically operating a methanation plant, which address at least one of the disadvantages of the known operating methods and control devices. It is in particular an object of the present disclosure to provide a computer-implemented method and a methanation plant control device for dynamically operating the methanation plant in view of changing or varying input variables.

[0016] According to the present disclosure, these objects are addressed by the features of the independent claims. In addition, advantageous embodiments follow from the dependent claims, figures and the description.

[0017] According to the present disclosure, a computer implemented method for dynamically operating a methanation plant for producing methane and I or methanol is provided. The method comprises as a first step to provide or access a digital plant twin of the methanation plant. The digital plant twin is a virtual digital reproduction or digital plan / map of the methanation plant. The digital plant twin comprises a plurality of digital components each representing at least one methanation plant component of the methanation plant or a component assembly or group. The methanation plant comprises a plurality of different components, which form in combination the methanation plant and which are configured to fulfill different tasks for the production of the methane. Such components are e.g. pipes, heaters, reactors, valves, heat exchangers, electrolysers, filters etc. A plurality, preferably all of these components, are virtually represented in the digital plant twin. The digital plant twin further comprises operating boundary conditions for the plurality of components. The respective boundary conditions determine e.g. the temperature range or the pressure range within which the respective components are operational. In other P28763PC00

[0018] 4 / 35 words, the operating boundary conditions determine the required parameters for operating each component and / or a component group and I or the entire methanation plant.

[0019] The computer implemented method further comprises the step of receiving an estimated electric energy profile indicative of the expected available electric energy to the methanation plant. The expected available electric energy is an important information for the operation of the methanation plant. The methanation plant, in particular its different components, require electric energy for its operation. E.g. different heaters, pumps, valves etc. require electric energy for the desired operation. These components and the entire methanation plant are operable within a predetermined range of available electric energy, which produces the desired methane output. E.g. 100% of maximum available electric energy produces 100% of the maximum possible methane, within a given time period. Further, 80% of maximum available electric energy produces 75% of the maximum possible methane, within a given time period e.g. because some components may not be useable in this scenario.

[0020] The computer implemented method further comprises the step of receiving, a required methane output profile indicative of the required methane output of the methanation plant. The required methane output profile determines the amount of methane, which should be produced e.g. 100 cubic meters per hour. The target is to produce the methane and directly feed the methane into a natural gas grid or directly provide the methane to a respective industrial plant. Methane could be produced and stored, but storing further increases the costs. It is therefore the target to produce the methane on demand, which is why the required methane output profile may vary over time. In this case it is possible to reduce buffer capacity and to further reduce the production costs.

[0021] The computer implemented method further comprises the step of determining the control commands for operating the methanation plant using the digital plant twin, the estimated P28763PC00

[0022] 5 / 35 electric energy profile and the required methane output profile. The control commands are e.g. determined by the digital plant twin, which uses the different input variables, in particular the estimated electric energy profile and the required methane output profile, and calculates the required control commands as output variables. In other words, the digital plant twin preferably determines the control commands for the real methanation plant such that the desired methane output is realizable with the available input variables. For example, the estimated electric energy profile determines that for the next hour 50% of the maximum electric energy is available, at the same time the required methane output profile determines that 40% of the maximum possible methane needs to be produces. Based on these input variables and the operating boundary conditions of the different components the digital plant twin calculates and determines the respective control commands to run the methanation plant for the next hour such that the required methane is produced as efficient as possible.

[0023] The digital plant twin is preferably configured to determine based on respective input variables control commands for operating the methanation plant. In other words, the digital plant twin is not only the digital image of the real methanation plant, but is also configured to calculate control commands for the real methanation plant. The different input variables are used by the digital plant twin to calculate the control commands for the methanation plant, in particular for the different components. Input variables are information on external influencing factors of the methanation plant, in particular information on available base products for the methanation, information on the available energy supply, information on the methane demand, and I or information on environmental surrounding conditions.

[0024] According to the present disclosure the computer implemented method creates the possibility to dynamically control a methanation plant with varying input variables, in particular such that the different components, the different component assemblies and the P28763PC00

[0025] 6 / 35 entire methanation plant is operable as efficient as possible. In particular, it is possible to plan ramp up processes and shot down processes of components of the methanation plant due to changing input variables such that the components are not operated out of the preferred operating range and thereby negatively affected. The computer implemented method disclosed enables to produce green methane and I or methanol advantageously efficiently since it allows to operate a methanation plant with renewable input variables.

[0026] The digital plant twin may use an optimization algorithms for determining the control commands. Determining the control commands is e.g. an optimization problem, solved by the digital plant twin using the input variables and a respective calculating optimization algorithm. The calculating algorithm may use numerical methods, in particular for nonlinear optimization. The nonlinear optimization algorithm is e.g. an Interior Point Optimizer (IPOPT). The digital plan twin, in particular at least one processor used by the digital plant twin, uses the calculating algorithm to determine the respective control commands. The optimization algorithm may further or additionally use machine learning methods or algorithms for determining the control commands. In particular, the machine learning algorithms may use trained neural networks.

[0027] In an embodiment, the digital plant twin is further configured to receive at least one sensor signal, which is indicative of current operating conditions of at least one component of the methanation plant, wherein the control commands are determined further using the at least one sensor signal. The methanation plant comprises preferably a plurality of sensors, which are configured to measure parameters of the different components. E.g. temperature sensors, pressure sensors, flow sensors, gas sensors etc. are provided at the respective positions in the methanation plant. At least one of these sensors provide the respective sensor signal to the digital plant twin as input variable. E.g. the current temperature of a reactor or the current pressure in an electrolyser may require that the P28763PC00

[0028] 7 / 35 respective component is controlled deviating from the standard procedure. Further, such sensor signals may determine that one component is fully operable or not. Such information may influence the determination of the control commands by the digital twin, which further increase the efficiency of the operation of the methanation plant.

[0029] In an embodiment, the computer-implemented method further comprises the step of operating, the methanation plant using the determined control commands for producing the required methane. In this step, the determined control commands are transmitted to the methanation plant, in particular to its specific components, and the methanation plant, in particular the specific components, are controlled respectively, by the control commands.

[0030] In a further embodiment, the computer-implemented method further comprises the step of updating, in particular by the digital plant twin, the determined control commands, in case input variables change. Changing input variables comprise e.g. changing sensor signals, changing estimated electric energy profile and I or changing required methane output profile. Other changing input variables may also require to update the control commands. The control commands are e.g. constantly or after predetermined time intervals updated, in case at least one input variable changed, which requires to update the control commands. The periodical update is e.g. performed each week, preferably, each day, preferably each hour, even more preferably each minute. In case the input variables do not change the methanation plant can be operated as expected and as determined. This is for example the case, when the estimated electric energy profile and the required methane output profile do not change and no sensor signal requires any adaptation of the control commands. The operation of the methanation plant can executed, by the control commands, as determined at the beginning. It is of course also possible that the input variables change over time, e.g. the estimated electric energy profile available may increase or decrease, which determines that more or less electric energy is available. By periodically or constantly updating the control commands it is in particular possible to P28763PC00

[0031] 8 / 35 efficiently control the methanation plant in case of varying input variables, which further helps to reduce the buffer capacities.

[0032] In a further embodiment, the input variables are received for a predetermined timespan and the control commands are determined for the predetermined timespan. For example, the estimated electric energy profile and the required methane output profile is received for the predetermined timespan. The predetermined timespan is for example, a plurality of months, one month, a plurality of weeks, one week, a plurality of days, one day, a plurality of hours, one hour, a plurality of minutes or one minute. A combination of the aforementioned timespans is also conceivable. For example, the digital plant twin receives for a predetermined timespan e.g. of the next week the input variables and determines the control commands for the next week. The next day, new input variables for the next week are received e.g. the same or varying input variables, which may cause the digital plant twin to update the control commands. The control commands are e.g. updated every day until the respective day for operation is reached and the respective current control commands are used for controlling the methanation plant. This updating may be performed for each upcoming timespan until the respective timespan is reached, which triggers the operation of the methanation plant with the respective control commands. Further, the at least one sensor signal may additionally be used to determine and update the control commands for the methanation plant.

[0033] In an embodiment, the estimated electric energy profile comprises an estimated renewable electric energy profile, which determines the expected available renewable electric energy, in particular for the predetermined timespan. Renewable electric energy comprises e.g. solar electric energy or wind electric energy. Other renewable electric sources are of course also conceivable. Renewable electric energy often varies over time. In other words, renewable electric energy, in particular from one or small number of sources, is not as constant as e.g. from conventional power sources like a coal power P28763PC00

[0034] 9 / 35 plant. The renewable electric energy profile determines the expected available renewable electric energy to the methanation plant for the future, in particular for the predetermined timespan, e.g. for the next week. The renewable electric energy profile may be dependent on predicted weather conditions like wind velocity or a degree of cloudiness. These predicted weather conditions may be updated constantly or periodically, which requires that the estimated renewable electric energy profile is updated. The estimated renewable electric energy profile, preferably constantly updated, is used to determine the control commands, such that the control commands include the estimated renewable electric energy profile.

[0035] In a further embodiment, receiving the estimated electric energy profile comprises to receive a plurality of individual estimated electric energy profiles, which indicate the available electric energy from different power plants, wherein the plurality of individual estimated electric energy profiles are combined to the estimated electric energy profile. The estimated electric energy profile may therefore be a combination of the plurality of estimated electric energy profiles, which indicate the available electric energy from different power plants, in particular for the predetermined timespan. For example, different electric energy plants are located in the vicinity of the methanation plant and are configured to provide electric energy to the methanation plant. One of these plants is e.g. a solar power plant, another one a wind power plant and third one a hydrogen power plant. All of these power plant provide their estimated electric energy profile, which determines the expected available power over time. The digital plant twin is configured to combine all of the received estimated electric energy profiles together to the combined estimated electric energy profile, which determines the expected available electric energy for the methanation plant. In particular renewable power plants are strongly dependent on weather conditions, combining a plurality of estimated electric energy profiles from different plants helps to increase the reliability and the manageability of deviations from the expected. Further it advantageously helps to reduce buffer capacity. P28763PC00

[0036] 10 / 35

[0037] In an embodiment, receiving the required methane output profile comprises to receive a plurality of customer individual methane requests, wherein the plurality of customer individual methane requests are combined to the required methane output profile. In other words, the required methane output profile therefore is a combination of a plurality received methane requests, in particular for the predetermined timespan. The required methane output profile of the methanation plant is preferably determined not only in dependence of the available electric energy and the maximum possible methane output, by using the available electric energy. In this case, it could be required to store methane, exceeding the demand in a buffer. This should be reduced. By using the required methane output profile from a plurality methane requests it is possible to produce on demand such that storing methane is reduced as much as possible. A plurality of costumers, which order methane for specific timespans determine the required methane output profile in that these received orders or requests are combined to the required methane output profile. The produced methane is preferably supplied to the customers e.g. via a methane grid or methane container.

[0038] In an embodiment, the methanation plant components comprise a plurality of electrolys- ers, which are configured to produce hydrogen using electric energy and water, wherein each electrolyser provides as operating boundary condition an efficiency profile, which determines the efficiency at different operating conditions, and wherein the determined control commands comprise instructions to operate the plurality of electrolysers. Hydrogen is an important component to produce methane. Hydrogen may either be provided to the methanation plant or is produced by the methanation plant itself. In this embodiment, the methanation plant comprises a plurality of electrolysers, preferably six, which are configured to produce hydrogen using the provided electric energy. Further they use water, which is provided to the methanation plant. The electrolysers form components of the methanation plant and are represented in the digital plant twin accordingly. Also the operating boundary conditions of the electrolysers are represented in the digital plant P28763PC00

[0039] 11 / 35 twin. The efficiency profile determines e.g. the hydrogen output of one of the electrolys- ers in dependence of the available electric energy and water to the electrolysers. Other boundary conditions may include preferred temperature ranges and pressure ranges and I or ramp up or ramp down requirements. Respective input variables for the digital plant twin are e.g. water supply, the estimated electric energy profile, in particular available for the respective electrolysers, the required methane output profile, in particular the required hydrogen output profile required for producing the methane output profile. The digital plant twin determines the control commands using the input variables and the operating boundary conditions. The control commands may determine that all or only a plurality of electrolysers should be operated at the given time period, in particular at 100% capacity or lower. For example, the control commands for the predetermined timespan may determine that three of the available six electrolysers should be operated at 80% capacity due to the respective input variables.

[0040] It is further preferred that the control commands are determined using boundary conditions, which consider lifespan boundary conditions and I or efficiency profiles. Such boundary conditions may determine that it is more lifespan efficient to operate an elec- trolyser at 80% capacity. The lifespan boundary conditions are in particular no linear curve. Further, also the efficiency profile is not a linear curve but determines at least one or more most efficient operating points. The digital plan twin may be configured to determine the control commands such that as many electrolysers as possible are operated at or as close as possible to their at least one most efficient operating point. The control commands for the electrolysers may comprise a load profile for the next timespan with e.g. second based sampling.

[0041] The determination of the control commands of the plurality of electrolysers by the digital plant twin is a sub optimization problem, which is solved by the digital plant twin, in par- P28763PC00

[0042] 12 / 35 ticular using a calculation algorithm. The calculating algorithm may use numerical methods, in particular for nonlinear optimization. The nonlinear optimization algorithm is e.g. an Interior Point Optimizer (IPOPT). The digital plan twin, in particular at least one processor used by the digital plant twin, uses the calculating algorithm to determine the respective control commands for the plurality of electrolysers.

[0043] In an embodiment, the methanation plant components comprise at least one reactor, which is configured to produce methane using hydrogen and carbon dioxide, wherein the at least one reactor provides operating boundary conditions, which determine the operating efficiency at different operating conditions, and wherein the determined control commands comprise instructions to operate the at least one reactor. Hydrogen and carbon dioxide may either be provided to the methanation plant or is produced by the methanation plant itself as described above by the plurality of electrolysers. Further the reactor, e.g. its components require electric energy, which is provided to the methanation plant. The reactor forms a components of the methanation plant and is represented in the digital plant twin accordingly. Also the operating boundary conditions of the reactor and its components are represented in the digital plant twin. The efficiency profile of the reactor determines e.g. the methane output of one of the reactor in dependence of the available electric energy, carbon dioxide and hydrogen. Other boundary conditions may include preferred temperature ranges and pressure ranges and I or ramp up or ramp down requirements. Respective input variables for the digital plant twin are e.g. carbon dioxide supply, hydrogen supply, the estimated electric energy profile, in particular available for the respective electrolysers and I or the required methane output profile. The digital plant twin is configured to determine the control commands using the input variables and the operating boundary conditions. The control commands may determine that the reactor should be operated at the given time period, in particular at 100% capacity or lower. P28763PC00

[0044] 13 / 35

[0045] It is further preferred that the control commands are determined using boundary conditions, which consider lifespan boundary conditions of the reactor and I or an efficiency profile. Such boundary conditions may determine that it is more lifespan efficient to operate the reactor at 75% capacity at a given temperature. The lifespan boundary conditions are in particular no linear curve. Further, also the efficiency profile is not a linear curve but determines at least one or more most efficient operating points. The digital plan twin may be configured to determine the control commands such that the reactor is operated at or as close as possible to its at least one most efficient operating point. The control commands for the electrolysers may comprise a load profile for the next timespan with e.g. second based sampling.

[0046] The determination of the control commands of the at least one reactor by the digital plant twin is a sub optimization problem, which is solved by the digital plant twin, in particular using an calculation algorithm. The calculating algorithm may use numerical methods, in particular for nonlinear optimization. The nonlinear optimization algorithm is e.g. an Interior Point Optimizer (IPOPT). The digital plan twin, in particular at least one processor used by the digital plant twin, uses the calculating algorithm to determine the respective control commands for the at least one reactor.

[0047] In an embodiment, the methanation plant components comprise at least one auxiliary component, which is configured to support the operation of the methanation plant, wherein the at least one auxiliary component provides operating boundary conditions, which determine the operating at different operating conditions, and wherein the determined control commands comprise instructions to operate the at least one auxiliary component. The auxiliary components are e.g. components of the plurality of electrolysers, of the reactor of standalone components. All the components together form the methanation plant. Auxiliary components may include pipes, valves, tanks, compressors, fluid circuits, heaters, heat exchangers, mixers, separators etc. All of these components or at P28763PC00

[0048] 14 / 35 least some of them need to receive at least one control command such that the methana- tion plant is operable as desired in dependence of the input variables and their respective boundary conditions. The auxiliary components may need electric energy and I or other input for the desired operation. The auxiliary components form components of the methanation plant and are represented in the digital plant twin accordingly. Also the operating boundary conditions of the auxiliary components are represented in the digital plant twin. One boundary condition may be an efficiency profile, which determines e.g. the efficiency of the respective auxiliary component at given input variables. Other boundary conditions may include preferred temperature ranges and pressure ranges and I or ramp up or ramp down requirements. Respective input variables for the digital plant twin are e.g. the estimated electric energy profile, in particular available for the respective auxiliary components, etc. The digital plant twin is configured to determine the control commands for the auxiliary components using the input variables and the operating boundary conditions. The control commands may determine how the respective auxiliary components are operated.

[0049] It is further preferred that the control commands are determined using boundary conditions, which consider lifespan boundary conditions and I or efficiency profiles of the auxiliary components. Such boundary conditions may determine that it is more lifespan efficient to operate a specific component at 80% capacity or another one at 100 % capacity. The lifespan boundary conditions are in particular no linear curve. Further, also the efficiency profile may not be a linear curve but determines at least one or more most efficient operating points. The digital plan twin may be configured to determine the control commands such that as many auxiliary components as possible are operated at or as close as possible to their at least one most efficient operating point. The control commands for the auxiliary components may comprise a load profile for the next timespan with e.g. second based sampling. P28763PC00

[0050] 15 / 35

[0051] The determination of the control commands of the auxiliary components by the digital plant twin is a sub optimization problem, which is solved by the digital plant twin, in particular using a calculation algorithm. The calculating algorithm may use numerical methods, in particular for nonlinear optimization. The nonlinear optimization algorithm is e.g. an Interior Point Optimizer (IPOPT). The digital plan twin, in particular at least one processor used by the digital plant twin, uses the calculating algorithm to determine the respective control commands for the auxiliary components.

[0052] By solving all of the sub optimization of the different components of the methanation plant, it is possible to determine, by the digital twin, respective control commands for all components of the methanation plant, such that the methanation plant is as a whole operable as efficient as possible with the available input variables.

[0053] In a further embodiment, the plurality of electrolysers, the at least one reactor and I or the at least one auxiliary component comprise at least one sensor, which is configured to provide a sensor signal indicative of at least one current operating condition of the respective component of the methanation plant, wherein the determined control commands for the plurality of electrolysers, the at least one reactor and I or the at least one auxiliary component are determined by the digital plant twin further using the at least one sensor signal. The sensor signal may be indicative of a temperature, a pressure, a gas composition, a humidity, at the respective component, which determines the current state of the respective component. E.g. the temperature of the reactor is crucial for the production of methane, in case the temperature exceeds a predetermined threshold value, the production of methane is negatively affected. Information on the current state of the temperature in the reactor may lead to determine, by the digital twin, control commands, which are used to control the reactor such that the temperature is reduced. Such a control command may lead a cooling circuit of the reactor to pump more coolant through the P28763PC00

[0054] 16 / 35 reactor. Similarly, control commands for the other components of the methanation plant may be determined by additionally using the received sensor signals.

[0055] In an embodiment, the operating boundary conditions of the different components of the methanation plant comprise at least one of: a temperature range, within which the respective component is operable, a pressure range, within which the respective component is operable, a fluid composition range or an element concentration range, within which the respective component is operational. For example, each of the electrolysers are configured to be operated in a preferred temperature range and in a preferred pressure range etc. Below or above the respective ranges the operation of the electrolysers is not possible or not as efficient as possible. By considering these ranges it is possible to further optimize the operation of the different components and therefore of the methanation plant.

[0056] In a further embodiment, the operating boundary conditions further comprise at least one of: a ramp-up profile of at least one component of the methanation plant, ramp-down profile of at least one component of the methanation plant, or a lifetime profile of at least one component of the methanation plant, wherein the control commands are determined by the digital plant twin further using at least one of these operating boundary conditions. Many conventional components of a methanation plant are designed and developed for a steady state operation. The steady state operation is in view of varying input variables not applicable. It is therefore required to dynamically operate the methanation plant and in particular its components. Dynamically operating in particular includes to control the ramp up and the ramp down of different components e.g. the electrolysers and the reactor, more often compared to a steady state operation. Further, such a dynamic operation may lead to lower lifespans of the different components. This embodiment considers these boundary conditions in order to ensure that the different components and the entire P28763PC00

[0057] 17 / 35 methanation plant is operated as efficient as possible in view of varying input variables. In addition, the buffer can be advantageously reduced as much as possible.

[0058] According to a further aspect of the present disclosure, a methanation plant control device is specified. The methanation plant control device is configured to determine control commands for dynamically operating a methanation plant, wherein the methanation plant control device comprises a processor.

[0059] The methanation plant control unit or device, in particular its processor, is configured to access a digital plant twin of the methanation plant, which comprises a plurality of digital components each representing at least one methanation plant component of the methanation plant. The digital plant twin further comprises respective operating boundary conditions for the plurality of components, within which the respective methanation plant components are useable. The digital plant twin is preferably configured to determine based on respective input variables control commands for operating the methanation plant.

[0060] The methanation plant control unit, in particular its processor, is configured to receive, an estimated electric energy profile indicative of the expected available electric energy to the methanation plant.

[0061] The methanation plant control unit, in particular its processor, is configured to receive, a required methane output profile indicative of the required methane output of the methanation plant.

[0062] The methanation plant control unit, in particular its processor, is configured to determine, the control commands for operating the methanation plant using the operating boundary conditions, the estimated electric energy profile and the required methane output profile. P28763PC00

[0063] 18 / 35

[0064] The methanation plant control unit may be a single device or a plurality of physical devices arranged at the methanation plant. Further, the methanation plant control unit may additionally or alternatively also be arranged remotely or may be implemented as a server, in particular as a cloud server.

[0065] In an embodiment, the methanation plant control unit, in particular its processor, is further configured to determine the control commands for dynamically operating the methanation plant as described above and hereinafter. Each feature and any respective advantage disclosed and described with respect to the computer implemented method for dynamically operating the methanation plant is also applicable mutatis mutandis to the above disclosed aspect of the methanation plant control device. In particular each feature disclosed and described with respect to the computer implemented method may be used to limit the methanation plant control device and vice versa.

[0066] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

[0067] BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The present disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing: P28763PC00

[0069] 19 / 35

[0070] Fig. 1 a schematic view of a methanation of methane and I or methanol using a methanation plant;

[0071] Fig. 2 a schematic representation of the methanation plant of Figure 1 with a detailed representation of the different components;

[0072] Fig. 3 a schematic representations of a control unit of the methanation plant as shown in the Figures 1 and 2 including the different input variables for determining the control instructions for the methanation plant;

[0073] Fig. 4 a schematic illustration of a plurality of power plants, which are configured to provide their individual electric energy to the methanation plant;

[0074] Fig. 5 a schematic illustration of a plurality of methane customers, which are configured to provide their individual methane request to the methanation plant;

[0075] Fig. 6 shows a flow diagram illustrating schematically a plurality of steps performed by the control unit for dynamically operating the methanation plant 1 as e.g. illustrated with respect to Figure 3.

[0076] DESCRIPTION OF THE EMBODIMENTS

[0077] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts. P28763PC00

[0078] 20 / 35

[0079] Figure 1 shows a schematic view of a methanation of methane and I or methanol using a methanation plant 1. Figure 1 focuses on the fluid and energy input and output, which is required to produce the desired methane and I or methanol. The methanation plant 1 comprises at least one electrolyser 20 and a reactor 25. The electrolyser 10 is configured to produce hydrogen 11 and oxygen 10 using water 5 and electric energy 3, and the reactor 25 is configured to produce methane 8 and I or methanol using the produced hydrogen 6, carbon dioxide 4 and electric energy 3. The electric energy 3, the water 5 and the carbon dioxide 4 are the plant input variables 2. In another embodiment, the hydrogen 6 is not produced by the plant 1 itself, but may be supplied directly to the plant 1. In this case also the hydrogen 6 would be a plant input variable 2. The methanation plant 1 is configured to perform the electrolysis of water 5 using one or more electrolysers 20 to disperse water 5 into hydrogen 6 and oxygen 10. At least the hydrogen 6 is further used in the reactor 25 of the methanation plant 1. The reactor 25 is configured to produce methane 8 and I or methanol using the produced hydrogen 6, supplied carbon dioxide 4 and electric energy 3. A side product of the reactor 25 is waste water 9. The waste water 9 may be reused as input water 5 for the methanation plant 1. A further side product of the at least one electrolysers 20 is the oxygen 20. The methane 8 and I or methanol, the waste water 9 and the oxygen 10 are output variables 7 of the methanation plant 1.

[0080] Figure 1 shows the methanation plant 1 in a super simplified manner, nevertheless, the most relevant input variables 2 and the resulting output variables 7 are shown in Figure 1.

[0081] Figure 2 shows the methanation plant 1 schematically in a more detailed manner. The methanation plant 1 comprises six electrolysers 20, which are configured to produce the required hydrogen 6. Each of the electrolysers 20 is supplied with electric energy 3 and water 5. The water 5 may be waste water 9 from the plant 1 itself or fresh water or mixture thereof. The methanation plant 1 further comprises according to this embodiment a CO2 P28763PC00

[0082] 21 / 35 tank 21 , which is configured to provide carbon dioxide 4 to the methanation plant 1. In another embodiment the methanation plant 1 may have access to carbon dioxide 4 via respective carbon dioxide grid or a CO2 tank 21 outside of the methanation plant 1. The carbon dioxide 4 used is preferably biogenic carbon dioxide 4. In another embodiment, the methanation plant 1 may produce its own carbon dioxide 4. The methanation plant 1 further comprises a gas mixer 22, which is configured to collect and mix the hydrogen 6 produced from the electrolysers 20 and the carbon dioxide 4 from the CO2 tank 21. In other words, the gas mixer 22 forms the desired gas composition using at least the hydrogen 6 and the carbon dioxide 4. The methanation plant 1 further comprises a compressor 23, which is configured to set the gas pressure of the hydrogen and carbon dioxide mixture as desired. The compressor 23 is supplied with electric energy 3 for its operation. The methanation plant 1 further comprises a heater 24, which is configured to set the gas mixture temperature as desired e.g. by heating or by cooling of the gas mixture. The compressor 23 and the heater 24 are configured to set the properties of the gas mixture such as desired for the methanation. The methanation plant 1 further comprises two reactors 25 arranged in series, which are configured to receive the gas mixture and to synthesize methane 8 out of the supplied carbon dioxide 4 and hydrogen 6. In other variations, only one or a plurality of reactors 25 may be used, which are arranged parallel or in series with each other. Using a plurality of reactors 25 in series may increase the product yield.

[0083] The synthesis of methane 8 (methanation) from CO2 (as well as CO) is a strongly exothermic reaction that requires efficient heat removal from the reaction zone, particularly when carried out catalytically with short reaction times. Conventionally, random fixed- bed reactors are used. Catalyst pellets may be arranged randomly unstructured and may move freely. An alternative to the random fixed-bed reactors are structured fixed-bed reactors with a plurality of channels, which comprise a catalyst coating. These reactors comprise a solid body structure, which define the channels. The reactants stream P28763PC00

[0084] 22 / 35 through the channels and react in the channels with the catalyst coating. The reaction zone is therefore within the channels. For example, the document DE 10 2016 125 641 A1 discloses a process for production of a natural gas substitute from hydrogen-contain- ing gas mixtures using a reactor with channels.

[0085] Regardless of the reactor type employed, the strongly exothermic nature of methane synthesis requires careful control of the heat removal from the reaction zone for controlling the temperature inside the reactor zone. Heat removal of the reaction zone is particularly critical and challenging for structured fixed-bed catalysts. The methanation plant 1 comprises therefore a coolant circuit 26 for controlling of the temperature inside at least one of the reactors 25, in the embodiment of figure 2 of the upstream arranged reactor 25, which is important for ensuring a high quality and high purity product and for ensuring high yields of target product. In particular, the chemical equilibrium of the different chemical reactions taking place is temperature dependent. Typically, it is desirable to maintain the temperature within a narrow target temperature range, in which the balance between high product yield, high product purity and a fast reaction is advantageous. The coolant circuit 26 comprises a coolant heater 27 and a coolant pump 28. The coolant heater 27 is configured to set the temperature of the coolant and the coolant pump 28 is configured to set the flow rate of the coolant. The coolant used are e.g. coolant oils, water etc. The coolant circuit 26, in particular its components are supplied with electric energy 3 for the desired operation.

[0086] The methanation plant 1 further comprises a water separator 29 arranged downstream of the reactor 25 which is configured to separate the water 9 out of the product gas of the reactor 25. The separated waste water 9 may be reused by the methanation plant 1 itself. The water separator 29 may also be supplied with electric energy 3 for its operation. The methanation plant 1 further may comprise additional post processing components 30 like heaters filters etc. These components may also need electric energy 3 for P28763PC00

[0087] 23 / 35 their operation. The methanation plant 1 additionally comprises downstream of the separator 29 a compressor 31 , which is configured to set the pressure of the resulting methane 8 or green natural gas. The compressor 31 may additionally require for its operation electric energy 3. The resulting green natural gas 8 is supplied with the desired high purity quality and pressure to a gas grid 32, which is configured to transport the methane 8 to customers. In other embodiments, the produced methane 8 may be directly supplied to a customer.

[0088] Figure 2 further indicates a control unit 40, which is configured to control the methanation plant 1 , in particular all of the described components such that the components work together as desired for producing the methane 8 using the available input variables 2. Figure 2 further shows a sensor 33, which is configured to provide a sensor signal 34 to the control unit 40 indicative of a parameter of a component of the methanation plant 1. A plurality of sensors 33 are also conceivable.

[0089] Figure 3 shows a schematic representation of the control unit 40 of Figure 2, which uses a digital twin 50 of at least a portion of the methanation plant 1 for determining control instructions 42 for at least a portion of the methanation plant 1 for dynamically operating the methanation plant 1. The control unit 40 may comprise an electronic circuit or a processor 42 which is configured to process the input signals 42 into the desired control instructions 43 for the methanation plant 1. The control unit 40 may be a computer or a server at or remote from the methanation plant 1. The control unit 40 may also access a cloud server for determining the control instructions 43.

[0090] The digital plant twin 50 is a virtual representation of at least a portion of the methanation plant 1 , preferably of the entire methanation plant 1. The digital plant twin 50 comprises a plurality of digital components 51 each representing at least one real component of the methanation plant 1. The digital plant twin 50 further comprises for each representing P28763PC00

[0091] 24 / 35 digital component 51 operating boundary conditions 52, within which the respective methanation plant components of the methanation plant 1 are useable. The digital plant twin 51 is configured to virtually represent the methanation plant 1 and to determine based on respective input signals, which are indicative of the expected input variables, the control commands 43 for operating the methanation plant 1 as desired, in particular dynamically.

[0092] The control unit 40 is configured to receive an estimated electric energy profile 44, which is indicative of the expected available electric energy to the methanation plant 1 as an input signal.

[0093] The control unit 40 is further configured to receive a required methane output profile 45 which is indicative of the required methane output of the methanation plant 1 as an input signal.

[0094] The control unit 40 is further configured to receive additional input signals, which additionally may be used to determine the control commands 43.

[0095] The control unit 40 is configured to determine the control commands 43 for dynamically operating the methanation plant 1 by using the digital plant twin 50, and the input signals 42. The additional input signals 46 are e.g. a CO2 supply profile or a water supply profile.

[0096] Figure 3 indicates that the estimated electric energy profile 44 is received from a renewable power plant, in particular a wind power plant 62. The estimated electric energy profile 44 determines how much electric energy is to be expected at a given time from this wind power plant 62. As outlined above in detail, the different components of the methanation plant 1 require electric energy 3 for their operation. It is therefore crucial for the operation of the methanation plant 1 to know the available electric energy 3 to the P28763PC00

[0097] 25 / 35 plant 1. The estimated electric energy profile 44 is therefore an important information to determine the control commands 43.

[0098] Figure 3 further indicates a CH4 customer 64 which provides the required methane output profile 45 to the control unit 40. The required methane output profile 45 determines how much methane output the methanation plant 1 should produce, in particular within a given timeslot. The required methane output profile 45 may be determined from a single customer 64 or a plurality of customer 64. In order to reduce the storage requirements of the methanation plant 1 and to avoid penalty payments due to unexpected supply of methane 8 to the grid 32 etc. it is of high importance to produce as close as possible on demand. In other words, the methane 8 should be produced as required by the customers 64. It is therefore of high importance to receive the required methane output profile 45.

[0099] Figure 3 further indicates that the determined control commands 43 are provided to the methanation plant 1 , in particular to the respective components, such that the methanation plant 1 is controllable dynamically as desired. Figure 3 further indicates that at least one sensor signal 34 from a sensor 33 of the methanation plant 1 is provided to the control unit 40. The sensor signal 34 is in particular further used by the control unit 40 to determine the control commands 43 and I or to update the control commands 43. The sensor signals 34 provide a feedback loop to the control unit 40.

[0100] The control unit 40, in particular the processor 41 , is configured to access the digital twin 50 and I or to provide to the digital twin 50 all the input signals 42. The digital twin 50 performs the calculations, in particular optimization calculations, to determine the control commands 43. P28763PC00

[0101] 26 / 35

[0102] Figure 4 shows a plurality of power plants 60, 61 , 62, which are all configured to provide electric energy 3 to the methanation plant 1 . Figure 4 shows three power plants, namely a first solar power plant 60, a second solar power plant 61 and a wind power plant 62, which all provide electric energy 3 to the methanation plant 1. The different power plants are located at different geographical locations and are therefore subject to varying environmental conditions like wind or solar exposure. The wind and the solar exposure can be estimated such that each power plant may provide an individual estimated electric energy profile 44 to the control unit 40. The control unit 40 is configured to combine the received estimated electric energy profiles 44 to a combined estimated electric energy profile 44, which is the combination of the received electric energy profiles 44 for the given timespan t.

[0103] Figure 5 shows similarly a plurality of methane customers 64, which all provide to the control unit 40 their individual methane request 47 for the desired timespan t. The control unit 40 is configured to combine the plurality of individual methane requests 47 to the required methane output profile 45 for the predetermined timespan t. The required methane output profile 45 determines how much methane 8 has to be produced by the methanation plant 1 in the predetermined timespan t.

[0104] Figure 6 shows a flow diagram illustrating schematically a plurality of steps performed by the control unit for dynamically operating the methanation plant 1 as illustrated with respect to Figure 3. In the following paragraphs, described with reference to Figure 6 is a possible sequence of steps, performed by the control unit 40 for dynamically operating the methanation plant 1 .

[0105] In step SO, the control unit 40 accesses the digital plant twin 50 of the methanation plant 1. The digital plant twin 50 comprises the plurality of digital components 51 each representing at least one methanation plant component or an assembly or group of components of the real methanation plant 1. The digital plant twin 50 further comprises operating boundary conditions 52 of these components, which determine the operation of the P28763PC00

[0106] 27 / 35 respective components. The digital plant twin 50 is for example stored and maintained directly in the control device 40. In another embodiment, the digital plant twin 50 is stored and maintained on a server, preferably a cloud server, which is accessed by the control unit 40. In another embodiment, the control unit 40 may be implemented in a (cloud) server, which is accessed via a user interface. The digital plant twin 51 is configured to determine based on respective input variables 2 control commands 43 for operating the methanation plant 1.

[0107] In step S1 , the control unit 40, receives an electric energy profile 44 indicative of the expected available electric energy to the methanation plant 1 as one of the input variables 2.

[0108] In step S2, the control unit 40, receives a required methane output profile 45 indicative of the required methane output of the methanation plant 1 as another one of the input variables 2.

[0109] In step S3, the control unit 40, determines by using the digital plant twin 50, the control commands 43 for dynamically operating the methanation plant 1 using the operating boundary conditions 52, the estimated electric energy profile 44 and the required methane output profile 45. The digital plant twin 50 determines the control commands 43 for dynamically operating the methanation plant 1 in view of varying input variables 2.

[0110] In step S4, the control unit 40, operates the methanation plant 1 , in particular at least one component of the methanation plant 1 , using the determined control commands 43.

[0111] In step S5, the control unit 40, updates the control commands 43 in case at least one of the input variables 2 change. The expected electric energy profile 44 may chance due to changing weather conditions or the required methane output profile 45 may change because a customer 64 may increases or reduces its individual methane request 47. P28763PC00

[0112] 28 / 35

[0113] LIST OF DESIGNATIONS

[0114] 1 Methanation Plant 40 Control unit

[0115] 2 Plant Input variables 41 Processor

[0116] 3 Electric energy 42 Input signals

[0117] 4 Carbon dioxide 30 43 control commands

[0118] 5 Water 44 Estimated electric energy profile

[0119] 6 Hydrogen (H2) 45 Required methane output profile

[0120] 7 Plant output variables 46 Additional input signals

[0121] 8 Methane CH4 47 Individual methane request

[0122] 9 waste water 35 50 Digital twin

[0123] 10 Oxygen 51 Digital components

[0124] 20 Electrolyser 52 operating boundary conditions

[0125] 21 CO2 Tank 60 First solar power plant

[0126] 22 Gas mixer 61 Second solar power plant

[0127] 23 Compressor 40 62 Wind power plant

[0128] 24 Heater 63 Carbon dioxide supplier

[0129] 25 Reactor 64 CH4 Customer

[0130] 26 Coolant circuit

[0131] 27 Coolant heater t timespan

[0132] 28 Coolant pump 45 P electric energy

[0133] 29 H2O Separator 50 Providing / Accessing

[0134] 30 Post processing (heater etc.) 51 Receiving

[0135] 31 Compressor 52 Receiving

[0136] 32 Methane grid 53 Determining

[0137] 33 Sensor 50 S4 Operating

[0138] 34 Sensor signal S5 Updating

Claims

P28763PC0029 / 35PATENT CLAIMS1. A computer implemented method for dynamically operating a methanation plant(1) for producing methane (8) and / or methanol, the method comprising the steps of: a. Providing (SO) a digital plant twin (50) of the methanation plant (1), the digital plant twin (50) comprising: i. a plurality of digital components (51) each representing at least one methanation plant component of the methanation plant (1), and ii. respective operating boundary conditions (52) for the plurality of digital components (51), which determine the operation of the respective component of the methanation plant (1); b. Receiving (S1) an estimated electric energy profile (44) indicative of the expected available electric energy to the methanation plant (1); c. Receiving (S2) a required methane output profile (45) indicative of the required methane output of the methanation plant (1); d. Determining (S3) control commands (43) for operating the methanation plant (1) using the digital plant twin (50), the estimated electric energy profile (44) and the required methane output profile (45).P28763PC0030 / 352. The computer implemented method according to claim 1 , wherein the method further comprises the step of receiving at least one sensor signal (34), which is indicative of a current operating condition of at least one component of the methanation plant (1), wherein the control commands (43) are determined further using the at least one sensor signal (34).

3. The computer implemented method according to any one of the preceding claims, wherein the computer-implemented method further comprises the step of operating (S4), the methanation plant (1) using the determined control commands (43) for producing the required methane (8).

4. The computer implemented method according to any one of the preceding claims, wherein the computer-implemented method further comprises the step of updating (S5) the determined control commands (43), in case at least the digital plant twin (50), the estimated electric energy profile (44) and / or the required methane output profile (45) changes.

5. The computer implemented method according to any one of the preceding claims, wherein at least the estimated electric energy profile (44) and I or the required methane output profile (45) are received for a predetermined timespan (t) and the control commands (43) are preferably determined for the predetermined timespan (t) or for another predetermined timespan.

6. The computer implemented method according to any one of the preceding claims, wherein the estimated electric energy profile (44) comprises an estimated renewable electric energy profile, which determines the expected available renewable electric energy, in particular for the predetermined timespan (t).P28763PC0031 / 357. The computer implemented method according to any one of the preceding claims, wherein receiving (S1) the estimated electric energy profile (44) comprises to receive a plurality of individual estimated electric energy profiles (44), which indicate the available electric energy from different power plants (60, 60, 62), wherein the plurality of individual estimated electric energy profiles (44) are combined to the estimated electric energy profile (44).

8. The computer implemented method according to any one of the preceding claims, wherein receiving the required methane output profile (45) comprises to receive a plurality of customer individual methane requests (47), wherein the plurality of customer individual methane requests (47) are combined to the required methane output profile (45).

9. The computer implemented method according to any one of the preceding claims, wherein the methanation plant components comprise a plurality of electrolysers (10), which are configured to produce hydrogen (11) using electric energy (3) and water (5), wherein each electrolyser (10) provides to the digital plant twin (50) as operating boundary condition (52) an efficiency profile, which determines the efficiency at different operating conditions, and wherein the determined control commands (43) comprise instructions to operate the plurality of electrolysers (10).

10. The computer implemented method according to any one of the preceding claims, wherein the methanation plant components comprise at least one reactor (16), which is configured to produce methane (8) and I or methanol using hydrogen (11) and carbon dioxide (4), wherein the at least one reactor (16) provides to the digital plant twin (50) as operating boundary conditions (52) an efficiency profile, which determine the operating efficiency at different operating conditions, and whereinP28763PC0032 / 35 the determined control commands (43) comprise instructions to operate the at least one reactor (16).11 . The computer implemented method according to any one of the preceding claims, wherein the methanation plant components comprise at least one auxiliary component, which is configured to support the operation of the methanation plant (1), wherein the at least one auxiliary component provides to the digital plant twin (50) operating boundary conditions (52), which determine at least one operating parameter at different operating conditions, and wherein the determined control commands (43) comprise instructions to operate the at least one auxiliary component.

12. The computer implemented method according to any one of the claims 9 to 11 , wherein the plurality of electrolysers (10), the at least one reactor (16) and I or the at least one auxiliary component comprise at least one sensor (33), which is configured to provide a sensor signal (34) indicative of at least one current operating condition of the respective component of the methanation plant (1), wherein the determined control commands (43) for the plurality of electrolysers (10), the at least one reactor (16) and I or the at least one auxiliary component are determined by the digital plant twin (50) further using the at least one sensor signal (34).

13. The computer implemented method according to any one of the preceding claims, wherein the operating boundary conditions (52) of at least one of the components of the methanation plant (1) comprise at least one of: a temperature range, within which the respective component is operational, a pressure range, within which the respective component is operational, a fluid composition or an element concentration.P28763PC0033 / 3514. The computer implemented method according to any one of the preceding claims, wherein the operating boundary conditions (52) of at least one of the components of the methanation plant (1) comprise at least one of: a ramp-up profile of at least one component of the methanation plant (1), ramp-down profile of at least one component of the methanation plant (1), or a lifetime profile of at least one component of the methanation plant (1), wherein the control commands (43) are determined by the digital plant twin (50) further using at least one of these operating boundary conditions (52).

15. A methanation plant control unit (40), which is configured to determine control commands (43) for dynamically operating a methanation plant (1), wherein the methanation plant control unit (40) comprises a processor (41), which is configured to: a. Access (SO) a digital plant twin (50) of the methanation plant (1), which comprises: i. a plurality of digital components (51) each representing at least one methanation plant component of the methanation plant (1); and ii. respective operating boundary conditions (52) for the plurality of digital components (51), which determine the operation of the respective component of the methanation plant (1); b. Receive (S1) an estimated electric energy profile (44) indicative of the expected available electric energy to the methanation plant (1);P28763PC0034 / 35 c. Receive (S2) a required methane output profile (45) indicative of the required methane output of the methanation plant (1); d. Determine (S3) the control commands (43) for operating the methanation plant (1) using the digital plant twin (50), the estimated electric energy profile (44) and the required methane output profile (45).

16. The methanation plant control unit (40) according to claim 15, wherein the methanation plant control unit (40), in particular its processor (41), is further configured to determine the control commands (43) for dynamically operating the methanation plant (1) by performing the steps of the computer-implemented method of any one of the claims 1 to 14.

17. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to any one of claims 1 to 14.

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