Facility for producing fuel and process for producing fuel

Abstract

The present disclosure relates to a facility (1) for producing fuel (2). The facility (1) comprises a fuel production unit (3) comprising a fuel production reactor (31) configured to produce the fuel (2). The facility (1) further comprises a carbon dioxide source (4) configured to generate carbon dioxide and to supply at least some of the generated carbon dioxide (51) to the fuel production unit (3) for fuel production during operation of the fuel production unit (3). The carbon dioxide source (4) is further configured to supply, during a period of carbon dioxide underdemand from the fuel production unit (3), excess carbon dioxide (52) to a carbon dioxide storage unit of the facility (1). The carbon dioxide storage unit (6) comprises a liquefaction unit (61) for liquefying the excess carbon dioxide (52) and a storage tank (62) arranged downstream of the liquefaction unit (61) and configured to store the liquefied excess carbon dioxide.

Description

[0001] P29215PC00

[0002] 1 / 41

[0003] FACILITY FOR PRODUCING FUEL AND PROCESS FOR PRODUCING FUEL

[0004] FIELD OF THE DISCLOSURE

[0005] The present disclosure relates to a facility for producing fuel, in particular methane and / or methanol. The disclosure further relates to a process for producing fuel, which may be carried out using the facility disclosed herein.

[0006] BACKGROUND OF THE DISCLOSURE

[0007] Fuels such as methane or methanol are widely used sources of energy in different fields and applications, including for industrial and private use. For example, many industries rely on natural gas for heat production, and many homes use natural gas as a heat source.

[0008] To date, a large portion of these fuels derives from natural sources like oil fields. Relying on these natural sources is unsustainable and environmentally unfriendly for different reasons. For once, the natural sources of these fuels are limited, and their extraction is also increasingly challenging and costly. Furthermore, when burnt, the fuels generate carbon dioxide which accumulates in the atmosphere, thereby contributing to climate change. For these and many other reasons, alternatives to natural gases are needed.

[0009] Different energy sources and fuels are currently being explored in order to achieve a more sustainable energy supply. Each of the energy sources and fuels have their own advantages and limitations. For example, the handling of hydrogen is challenging, and hydrogen cannot be fed into the existing gas pipeline system of many countries. There-P29215PC00

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[0011] fore, the use of hydrogen would require a completely new pipeline system, which is expensive. Photovoltaic electricity generation by itself is appealing because it utilizes solar energy, but storage of photovoltaically generated electricity is challenging because it often requires expensive batteries. To overcome this problem, the generated electricity may be used to produce a chemical energy carrier such as methane or other hydrocarbons, methanol or hydrogen.

[0012] Out of the different fuel solutions available, renewable natural gas (RNG) has emerged as a particularly promising solution to achieving sustainable energy supply. RNG is a pipeline-quality gas that is fully interchangeable with conventional natural gas and can therefore make use of the expansive existing network and infrastructure for natural gas. Different sources of RNG have been identified to date, including the use of biowaste to fuel biogas fermentation plants to generate methane. A particularly appealing process to produce RNG is the Sabatier process in which hydrogen and carbon dioxide are used to produce methane. A significant advantage of this approach is that it concomitantly reduces the carbon dioxide footprint while generating fuel. Thus, the process allows to produce RNG with a particularly low product carbon footprint. In theory, even net negative carbon footprints can be achieved using this process. Consequently, RNG production has received much attention.

[0013] Despite the practical, economic and environmental appeals of RNG production from carbon dioxide, operating this process remains challenging for different reasons. The synthesis of methane, methanol or other fuels from carbon dioxide is a complex process which relies on a carefully controlled balance of various input parameters and sources. For example, a constant energy supply is typically required in order to reliably generate the fuel with a low carbon footprint. However, the need for a constant energy supply is incompatible with the use of sustainable energy sources such as photovoltaic electricity,P29215PC00

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[0015] which often suffers from intermittency issues. Furthermore, the fuel synthesis also requires a constant influx of carbon dioxide having certain parameters properties (e.g. a certain water content and pressure). Depending on the carbon dioxide source, it may be difficult to provide such a constant influx of carbon dioxide. Therefore, there is a need to improve control over the production of fuels from carbon dioxide. In particular, there is a need to dynamically and efficiently operate the fuel production facilities for the desired RNG production.

[0016] SUMMARY OF THE DISCLOSURE

[0017] It is an object of the present disclosure to provide a facility for producing fuel, particularly methane and / or methanol, and to provide a process for producing fuel, preferably methane and / or methanol, which address at least one of the disadvantages of the known facilities of the respective methods. It is a particular object of the present disclosure to provide a facility and a process for producing fuel with high efficiency and ideally with a lower product carbon footprint. In at least some embodiments, it is an object to provide a facility and a process for producing a fuel such as methane and / or methanol, which are able to operate with high efficiency despite intermittency issues or other irregularities or uncertainties in the supply of at least one input resource used, such as electricity supply and / or the supply of any raw materials used in the fuel production, such as carbon dioxide. In a preferred embodiment, a fuel production facility and a fuel production process would be provided which allow to efficiently produce fuels such as methane and / or methanol having a low product carbon footprint using carbon dioxide as raw material and photovoltaic electricity for energy supply. In at least some embodiments, the process would allow to produce the fuel (e.g. methane and / or methanol) with a low product carbon footprint both at day and at night.P29215PC00

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[0019] 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.

[0020] According to a first aspect of the present disclosure, a facility for producing fuel is provided. The facility comprises a fuel production unit comprising a fuel production reactor configured to produce the fuel. The facility further comprises a carbon dioxide source configured to generate carbon dioxide and to supply at least some of the generated carbon dioxide to the fuel production unit for fuel production during operation of the fuel production unit. The carbon dioxide source is further configured to supply, during a period of carbon dioxide underdemand from the fuel production unit, excess carbon dioxide to a carbon dioxide storage unit of the facility.

[0021] The facility further comprises the carbon dioxide storage unit. The carbon dioxide storage unit comprises a liquefaction unit for liquefying of the excess carbon dioxide. The carbon dioxide storage unit further comprises a storage tank arranged downstream of the liquefaction unit and configured to store the liquefied excess carbon dioxide. Depending on the application, the liquefied excess carbon dioxide may be stored at least temporarily, or even essentially permanently. Preferably, the excess carbon dioxide is stored temporarily, as described in further detail hereinafter.

[0022] By supplying excess carbon dioxide to the carbon dioxide storage unit during a period of carbon dioxide underdemand from the fuel production unit, the facility is able to accommodate intermittencies or other irregularities or uncertainties in the supply of the input resources used. For example, if the fuel production relies on an electricity source facing electricity supply intermittencies, as may e.g. be the case for photovoltaic electricity, the fuel production facility may accommodate these intermittencies by supplying the excess carbon dioxide to the storage unit for storage. A further use case may arise in instancesP29215PC00

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[0024] where the carbon dioxide source generates unexpectedly high amounts of carbon dioxide which cannot be processed in the fuel production. Once again, the excess carbon dioxide may be supplied to the storage unit for storage, allowing to accommodate the irregularities in the carbon dioxide supply. Ultimately, by accommodating the intermittency issues and the supply irregularities and uncertainties, the facility is able to operate with higher efficiency while still allowing to produce the fuel with a low product carbon footprint.

[0025] A further advantage is that the storage of the excess carbon dioxide is rendered particularly efficient because at least a portion of the excess carbon dioxide is stored in liquefied form.

[0026] An even further advantage is that the liquefaction of the excess carbon dioxide generated cold (i.e. negative heat), which may be used as a refrigeration source for other units or components of the facility, such as compressors, thereby obviating or at least reducing the need for external refrigeration.

[0027] The fuel production unit comprises the fuel production reactor configured to produce the fuel. To produce the fuel, the fuel production unit relies on several input resources, including raw material or reactant supply, and typically also energy supply. As an example, carbon dioxide is supplied to the fuel production unit as raw material. In a typical embodiment, hydrogen is also provided to the fuel production reactor as a further reactant. Thus, in a typical embodiment, the fuel (particularly methane) is produced from carbon dioxide and hydrogen, preferably using the Sabatier process. The hydrogen may e.g. be generated by one or more electrolysis units, which may also be comprised by the fuel production unit. Consequently, in this illustrated embodiment, the fuel production unit relies on carbon dioxide supply, hydrogen supply and energy supply. Since the methana-P29215PC00

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[0029] tion reaction and many other fuel-producing processes from carbon dioxide are exothermic, they further require maintaining a reaction temperature by cooling, thereby making the process further reliant on temperature control. Taken together, several input parameters (including reactant supply, energy supply, thermal management) need to be carefully balanced to operate a highly efficient process. Depending on the interplay of the various input parameters, the facility - and, more specifically, the carbon dioxide source - may be operated in different states.

[0030] For example, there may be a carbon dioxide underdemand from the fuel production unit, i.e. an underdemand for carbon dioxide from the fuel production unit. Generally speaking, a carbon dioxide underdemand may mean that, at a given point in time or in a given time interval (either a current time interval or a future time interval, e.g. based on expected or computed or extrapolated data), the supply of carbon dioxide from the carbon dioxide source exceeds the demand for carbon dioxide from the fuel production unit. There may be different reasons for such a demand-supply mismatch. For example, the carbon dioxide supply from the carbon dioxide source may be abnormally high and too high to be matched by an increase in carbon dioxide demand from the fuel production unit. It is also possible that the fuel production unit has a current (or expected future) supply shortage of another resource, e.g. a current (or expected future) shortage in hydrogen supply, which may cause the fuel production unit to correspondingly adapt the carbon dioxide demand in order to maintain a target stoichiometry between both reagents. The hydrogen supply may for example be caused by a current (or expected future) power shortage, potentially due to intermittency issues or other irregularities in the power supply (particularly the power supply to the one or more electrolysis units used for producing hydrogen). Further possible reasons for a mismatch between carbon dioxide supply from the carbon dioxide source and carbon dioxide demand from the fuel production unit include a potential current (or expected future) reduction in the capacity to cool (or heat, in the case of an endothermic process) the fuel production reactor efficiently. TheP29215PC00

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[0032] different exemplary factors outlined above may either occur individually or collectively or in any possible combination.

[0033] Thus, as outlined above, the term “carbon dioxide underdemand” primarily refers to a mismatch between (e.g. current and / or future) carbon dioxide supply from the carbon dioxide source and (e.g. current and / or future) carbon dioxide demand from the fuel production unit. It does not necessarily imply that the carbon dioxide demand is lower compared to a previous level, although this may be one possible scenario, as outlined above.

[0034] In the case of a carbon dioxide underdemand, the supply is greater than the demand, as explained above. However, a supply-demand mismatch may also occur in the opposite direction, i.e. where the (e.g. current and / or future) carbon dioxide demand from the carbon dioxide source exceeds the (e.g. current and / or future) carbon dioxide supply from the carbon dioxide source. Possible scenarios which may cause such a carbon dioxide overdemand include a (e.g. current and / or future) increase in the amount of hydrogen supplied to the fuel production reactor, which could e.g. be due to an increase in the power supply. Alternatively or in combination, it is also possible that the carbon dioxide supply from the carbon dioxide source has unexpectedly dropped below a previous level.

[0035] Generally speaking, supply-demand mismatches are undesirable in either direction. For example, a carbon dioxide underdemand from the fuel production unit would typically be reconciled either by temporarily stopping or reducing carbon dioxide supply from the carbon dioxide source or, if the carbon dioxide source cannot be easily reduced or stopped, releasing the excess carbon dioxide into the atmosphere. Both approaches lead either to inefficiencies or environmental pollution due to carbon dioxide release. Conversely, a carbon dioxide overdemand may lead to impure products and / or lower product yields because of the altered stoichiometric ratios of the reagents supplied to the reactor.P29215PC00

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[0037] The facility described herein offers a solution in that, during a period of carbon dioxide overdemand, excess carbon dioxide may be supplied to the carbon dioxide storage, as explained in further detail above. As used herein, it is understood that the term “excess carbon dioxide” in general refers to carbon dioxide generated by the carbon dioxide source which is supplied to the carbon dioxide storage unit, particularly during a period of carbon dioxide underdemand from the fuel production unit. Thus, the excess carbon dioxide may for example be the remaining portion of the carbon dioxide generated by the carbon dioxide source which is not directly supplied to the fuel production unit for direct use in fuel production. For example, the excess carbon dioxide may, at least in some embodiments, be defined as the portion of the carbon dioxide generated by carbon dioxide source which is not required by the fuel production unit for fuel production and which is therefore supplied to the carbon dioxide storage unit.

[0038] In at least some embodiments, the facility also offers a solution to the challenges of carbon dioxide overdemand. Preferably, the carbon dioxide storage unit is configured to supply, during a period of carbon dioxide overdemand from the fuel production unit, at least some of the stored excess carbon dioxide to the fuel production unit for fuel production during operation of the fuel production unit. By supplying at least some of the stored excess carbon dioxide from the carbon dioxide storage unit to the fuel production unit, the carbon dioxide overdemand from the fuel production unit can be met, thereby allowing an optimal stoichiometric ratio between the reagents to be maintained and the process to continue running efficiently. Furthermore, the resulting fuel maintains its (low) product carbon footprint.

[0039] Depending on the application, the stored excess carbon dioxide may be supplied from the carbon dioxide storage unit to the fuel production unit directly or indirectly, i.e. e.g. through intermediacy of one or more further units. Thus, in some embodiments, the carbon dioxide storage unit is configured to supply at least some of the stored excess carbonP29215PC00

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[0041] dioxide to the fuel production unit directly and / or through intermediacy of a carbon dioxide processing unit arranged in flow direction between the carbon dioxide storage unit and the fuel production unit.

[0042] Furthermore, depending on the application, the stored excess carbon dioxide may be supplied at different pressures and in different states. For example, in theory, because the excess carbon dioxide is preferably stored in liquid form, liquefied carbon dioxide may be supplied to the carbon dioxide processing unit (directly or indirectly). However, it is preferred to supply the stored excess carbon dioxide in gasified form. This is particularly preferably e.g. when operating Sabatier-type methanation processes at reagent processes of around 10 bar. Thus, in some embodiments, the carbon dioxide storage unit comprises an evaporation unit arranged downstream of the storage tank and upstream of the fuel production unit, wherein the evaporation unit is configured to evaporate the liquefied excess carbon dioxide and to supply the evaporated excess carbon dioxide to the fuel production unit, optionally through intermediacy of the carbon dioxide processing unit. By first evaporation the stored excess carbon dioxide before supplying it to the fuel production unit, the stored carbon dioxide can be incorporated into the process more easily.

[0043] In some embodiments, the pressure and temperature of the stored excess carbon dioxide may be adjusted such that it is compatible with the fuel production process. For example, if essentially no carbon dioxide is provided from the carbon dioxide source (e.g. due to a failure or maintenance down-time of the carbon dioxide source), it may be preferable for the evaporation unit to adjust the pressure and temperature of the stored excess carbon dioxide such that it essentially corresponds to the pressure and / or temperature of the carbon dioxide required by the fuel production unit. However, in cases where the stored excess carbon dioxide is provided to the fuel production unit along with carbonP29215PC00

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[0045] dioxide supplied to the fuel production unit from the carbon dioxide source, the temperature and pressure of both carbon dioxide input streams may be adjusted to be compatible with each other. For example, because the excess carbon dioxide is stored in liquefied form, it may be condensed to a relatively higher pressure and / or temperature than normally required by the fuel production unit, which would allow the carbon dioxide from the carbon dioxide source to be provided at a relatively lower pressure and / or temperature than normally required by the fuel production unit, wherein both pressure-temperature points would be chosen such that, after mixing both carbon dioxide input streams, a resulting mixed carbon dioxide input stream has the desired temperature and pressure as required by the fuel production reactor. Thus, in some embodiments, the evaporation unit is configured to adjust the temperature and / or pressure of the excess carbon dioxide such that it is complementary, with respect to a target carbon dioxide temperature and / or target carbon dioxide pressure, to the temperature and / or pressure of the generated carbon dioxide supplied from the carbon dioxide source to the fuel production unit.

[0046] In some embodiments, similar adjustments of the carbon dioxide input streams may be made with respect to other parameters of the input streams, such as water content. For example, because the excess carbon dioxide is stored in liquefied form, it is typically very dry. Thus, in period of carbon dioxide overdemand from the fuel production unit, mixing in very dry excess carbon dioxide (in liquid or gasified form) would allow the carbon dioxide from the carbon dioxide source to be supplied with higher water contents, which reduces the costs associated with a possible condensation pre-treatment. Thus, in some embodiments, the carbon dioxide processing unit is configured to adjust a water content of the carbon dioxide supplied directly from the carbon dioxide source to the fuel production unit through intermediacy of the carbon dioxide processing unit based on a water content input from the carbon dioxide storage unit, wherein the water content input from the carbon dioxide storage unit is indicative of a water content of the stored excess car-P29215PC00

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[0048] bon dioxide. Furthermore, the carbon dioxide processing unit may be configured to adjust the water content of the carbon dioxide supplied directly from the carbon dioxide source to the fuel production unit through intermediacy of the carbon dioxide processing unit such that an overall combined water content corresponds to a target water content of the fuel production unit.

[0049] It is understood that different adjustments may or may not be made independently of each other. For example, in some embodiments, only the water content is adjusted, while in further embodiments, the water content and also the temperature and pressure are adjusted.

[0050] The liquefaction unit of the carbon dioxide storage unit is configured to liquefy the excess carbon dioxide. Depending on the application, the liquefaction unit may be configured to liquefy at least some of the excess carbon dioxide, or essentially all of the excess carbon dioxide.

[0051] As outlined above, the carbon dioxide storage unit may e.g. be configured to supply at least some of the stored excess carbon dioxide to the fuel production unit for fuel production. More generally, depending on the application, the stored excess carbon dioxide can be used for many purposes or applications. For example, at least some of the stored excess carbon dioxide may be bottled and / or fed into a carbon dioxide grid and / or supplied to further units, e.g. co-located further units that also require carbon dioxide as input. A further possible use of the liquefied stored excess carbon dioxide is as refrigerant. Thus, in some embodiments, the carbon dioxide storage unit is configured to:

[0052] - supply at least some of the stored excess carbon dioxide to a further unit (e.g. a further co-located unit); and / orP29215PC00

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[0054] - to supply at least some of the stored excess carbon dioxide to a carbon dioxide grid; and / or

[0055] - to bottle at least some of the stored excess carbon dioxide; and / or

[0056] - to supply at least some of the liquefied stored excess carbon dioxide to a unit in need of refrigeration.

[0057] The unit in need of refrigeration may e.g. comprise one or more of the heat suppliers disclosed herein. It is understood that these further applications and uses can be chosen independently of (i.e. alternatively to or in addition to) whether at least some of the stored excess carbon dioxide is supplied to the fuel production unit for fuel production.

[0058] In some embodiments, the facility comprises a control unit. The control unit may e.g. be configured to:

[0059] - Compare a carbon dioxide supply level from the carbon dioxide source to a carbon dioxide demand level from the fuel production unit;

[0060] - Wherein if the carbon dioxide supply level exceeds the carbon dioxide demand level, the control unit is configured to instruct the carbon dioxide source to supply at least some of the excess carbon dioxide to the carbon dioxide storage unit for storage; and

[0061] - Wherein if the carbon dioxide demand level exceeds the carbon dioxide supply level, the control unit is configured to instruct the carbon dioxide storage unit to supply at least some of the stored excess carbon dioxide to the fuel production unit.P29215PC00

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[0063] In the case where the carbon dioxide supply level exceeds the carbon dioxide demand level, as explained above, this may be due to different reasons or a combination of different reasons, including e.g. carbon dioxide from the carbon dioxide source and / or electricity undersupply to the methane production unit. Irrespective of the specific reasons, in some embodiments, the carbon dioxide source is configured to supply excess carbon dioxide to the carbon dioxide storage unit during a period of carbon dioxide oversupply from the carbon dioxide source and / or during a period of electricity undersupply to the fuel production unit.

[0064] In the case where the carbon dioxide demand level exceeds the carbon dioxide supply level, once again, this may be due to different reasons, as explained above. Depending on the application, it could be advantageous that essentially all of the carbon dioxide generated from the carbon dioxide source is supplied to the fuel production unit in these cases. Thus, in some embodiments, the control unit is configured to instruct, if the carbon dioxide demand level exceeds the carbon dioxide supply level, the carbon dioxide source to supply essentially all of the generated carbon dioxide from the carbon dioxide source to the fuel production unit.

[0065] Depending on the application, supply and demand may be checked at - or with respect to - different time points or time periods. For example, real-time-control may be used to compare current supply and demand levels, but it is also possible to use the control unit to compare expected or projected future supply and demand levels. Thus, in some embodiments, the carbon dioxide supply level is a current carbon dioxide supply level, and the carbon dioxide demand level is a current carbon dioxide demand level. Alternatively or in combination, the carbon dioxide supply level may be a future carbon dioxide supply level, and the carbon dioxide demand level may be a future carbon dioxide demand level.P29215PC00

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[0067] Depending on the application, the control unit may compare the carbon dioxide supply level and the carbon dioxide demand level to each other in different ways and based on different information inputs. For example, in cases where the fuel production unit (and possibly also other units or components of the facility) are powered by an electricity power source, it is possible to determine the carbon dioxide demand level based on the electricity supply. This is e.g. advantageous in methanation applications in which the hydrogen for the methanation is obtained by electrolysis and where the electrolysis in turn is powered by electricity. Alternatively or in combination, the hydrogen supply may also be used as a possible input to infer the carbon dioxide demand. More generally, in some embodiments, the control unit is further configured to determine the carbon dioxide demand level from the fuel production unit based on an electricity supply level input from the power source and / or based on a hydrogen supply level input from a hydrogen source of the fuel production unit. The hydrogen supply level input may e.g. be indicative of a current and / or a future hydrogen supply from the hydrogen source.

[0068] Depending on the application, it could be advantageous to ensure throughout the process that the carbon dioxide storage unit never runs full but that it always retains some storage capacity in order to avoid potential scenarios where carbon dioxide can neither be consumed by the fuel production unit, nor temporarily be taken up by the carbon dioxide storage unit, which could jeopardize the product carbon footprint. Different approaches to achieve this may be envisioned. For example, one approach involves supplying at least some of the stored excess carbon dioxide to the fuel production unit if the carbon dioxide storage unit reaches a certain fill level. Thus, in some embodiments, the control unit is configured to:

[0069] determine a fill level of the storage tank; andP29215PC00

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[0071] - the control unit is further configured to supply, if the determined fill level exceeds a predetermined threshold, at least some of the stored excess carbon dioxide to the fuel production unit for fuel production, preferably until the determined fill level no longer exceeds the predetermined threshold.

[0072] In addition to that, it may be desirable, at least in some optional cases, to further control the facility such that the carbon dioxide demand from the fuel production unit is increased and / or the carbon dioxide supply from the carbon dioxide source is decreased in order to accommodate the additional carbon dioxide provided by the carbon dioxide storage unit. For example, the electricity supply (and, therefore, for example the hydrogen supply) may be increased in response in order to increase the carbon dioxide demand from the fuel production unit.

[0073] Thus, in some embodiments, the control unit is configured to instruct, if the determined fill level of the storage tank exceeds a predetermined threshold, the fuel production unit to increase carbon dioxide demand. This may e.g. involve instructing the power source to increase an electricity supply to the fuel production unit.

[0074] These embodiments are particularly advantageous because they allow to still consume all freshly generated carbon dioxide from the carbon dioxide source, as well as to consume the additional excess carbon dioxide supplied from the storage tank, thereby preventing the tank from exceeding the predetermined fill level or from even running full, which ultimately allows to maintain low carbon footprints of the fuel product.

[0075] Depending on the application, different predetermined thresholds may be used. For example, the predetermined threshold may e.g. correspond to a tank fill level of 75%, such as 85% or even 95% with respect to a total storage volume of the storage tank.P29215PC00

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[0077] In a further development, it has been recognized as part of the present disclosure that the cold (i.e. negative heat) that is generated during gasification of the stored excess carbon dioxide in the evaporation unit may be used as a valuable source of cold. For example, it may be used to neutralize the heat generated by different heat suppliers, such as the fuel production reactor (when operating an exothermic reaction such as the Sabatier process) or other heat suppliers. Thus, in some embodiments, the facility further comprises a heat exchanger thermally connecting the evaporation unit to one or more heat suppliers for cooling the one or more heat suppliers. These embodiments further increase the efficiency of the process by reducing the need for additional sources of cold or other refrigeration means. It is understood that because the heat exchanger thermally connects the evaporation unit to the one or more heat suppliers, the heat exchanger is typically arranged between the evaporation unit and the one or more heat suppliers (with respect to a thermal energy exchange system).

[0078] Depending on the application, different heat suppliers may benefit from the cold generated during carbon dioxide evaporation. For example, in some embodiments, the one or more heat suppliers comprise one or more of the following:

[0079] - The fuel production reactor;

[0080] - One or more carbon dioxide compressors of a / the carbon dioxide processing unit;

[0081] - A carbon dioxide pre-treatment unit of a / the carbon dioxide processing unit;

[0082] - The one or more electrolysis units;

[0083] - A hydrogen condensation unit for condensation of water out of a hydrogen stream generated by the one or more electrolysis units.P29215PC00

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[0085] For example, in the case of the electrolysis unit, ohmic heat may be generated during electrolysis, which may thus be neutralized. In the case of the hydrogen condensation unit, this hydrogen condensation unit may e.g. be used to ensure that the hydrogen stream is dried before being supplied to the fuel production reactor. Thus, the hydrogen condensation unit is typically arranged downstream of the one or more electrolysis units and upstream of the fuel production reactor.

[0086] Besides the evaporation unit, other units or components of the facility may also generate cold (i.e. negative heat) and may therefore optionally also be incorporated into the heat exchange system. For example, the biogas plant and / or a carbon dioxide capture plant and / or a preheating section of the methane production unit may also be used as heat consumers. In some embodiments, the heat exchanger thermally connects one or more heat consumers to the one or more heat suppliers, wherein the one or more heat consumers comprise the evaporation unit and further comprise:

[0087] - A biogas plant; and / or

[0088] - A carbon dioxide capture plant; and / or

[0089] - A pre-heating section of the fuel production unit, wherein the pre-heating section is configured for preheating input fluid streams of the fuel production unit, such as carbon dioxide and / or hydrogen.

[0090] Depending on the application and irrespective of the number of heat consumers and heat suppliers, the heat exchange may occur in different ways. For example, it would be conceivable that the heat exchanger comprises one or more thermal circuits using a single working fluid that thermally contacts the evaporation unit to one or more heat suppliers. However, to allow more control and to facilitate process management, it is preferable to use a plurality of working fluids which are thermally interconnected with each other in theP29215PC00

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[0092] heat exchanger. Thus, in some embodiments, the heat exchanger interconnects a plurality of at least two thermal circuits, wherein each thermal circuit has an individual working fluid.

[0093] Depending on the application, the facility described herein may be used for producing different fuels. It is understood that the fuel is produced at least in part from carbon dioxide. Typically, the fuel is produced from carbon dioxide and from hydrogen, which may e.g. be generated by electrolysis. In some embodiments, the fuel production reactor is configured to produce a hydrocarbon fuel and / or an alcohol, particularly a C(1-6) hydrocarbon and / or a C(1-6) alcohol. More specifically, in some embodiments, a linear C(1-6) hydrocarbon and / or a linear C(1-6) alcohol may be produced, such as a linear C(1-4) hydrocarbon and / or a linear C(1-4) alcohol. The C(1-6) alcohol (respectively C(1-4) alcohol) preferably has a single hydroxyl group, i.e. preferably has the chemical formula CnH2n+iOH, wherein n is an integer selected from 1 to 6 (respectively from 1 to 4). Typically, the hydroxyl group is positioned terminally. In some embodiments, the fuel production reactor is configured to produce a hydrocarbon fuel and / or methanol. In preferred embodiments, the fuel production reactor is configured to produce methane and / or methanol, preferably methane. Thus, in some embodiments, the fuel production reactor is a methanation reactor, and the fuel production unit may be labelled as methanation unit.

[0094] Depending on the fuel production used, the facility typically requires a power source, e.g. for electricity for one or more units or other components of the facility. For example, in some embodiments, the facility comprises a power source configured to provide electric energy to the fuel production unit during its operation (i.e. during operation of the fuel production unit). Optionally, the power source may also be configured to provide electric energy to other units, such as the carbon dioxide storage unit and / or the carbon dioxide source.P29215PC00

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[0096] Depending on the application, different power sources may be used. In some embodiments, it is conceivable to use electricity from an electricity grid. However, it some preferred embodiments, the power source is a power plant. The power plant may e.g. be configured to generate electric energy which is at least partially provided to the fuel production unit during its operation (i.e. during operation of the fuel production unit). In some embodiments, the power plant is a renewable energy power plant, in particular at least one of: a photovoltaic power plant, a wind power plant, a biogas power plant, a biomass power plant or a hydroelectric power plant. Preferably, the power plant is a photovoltaic power plant.

[0097] One advantage of the facility and the process described herein is that they are able to operate efficiently even if certain input supplies such as an electricity supply display intermittencies or other irregularities or uncertainties. This is typically the case for photovoltaic power plants, which are dependent on light and therefore produce essentially no electricity at night and reduced electricity during cloudy days or periods. Thus, in some embodiments, the power plant is configured to generate the electric energy intermittently.

[0098] Depending on the application, a large portion or even essentially all of the generated electric energy may be used directly by the fuel production unit and optionally any further electricity-consuming units. Indeed, because the facility and the process are able to accommodate intermittency issues or other supply irregularities, it is able to afford supplying a large fraction or even all of the generated electricity to the fuel production unit without the need to store some of the electric energy to bridge future electricity intermittencies (because such future intermittencies can e.g. be compensated by reducing the overall fuel production process by supplying less carbon dioxide as well). Consequently, the facility and process obviate the need for large energy storage capacities (e.g. in the form of batteries), which would be expensive.P29215PC00

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[0100] However, depending on the application, it may still be desirable to provide an energy storage unit in order to provide electricity for basic operations during electricity supply intermittencies. The capacity of these energy storage units can optionally be reduced compared to prior art facilities, thereby still allowing the benefits of the facility and process disclosed herein.

[0101] In some embodiments, the facility further comprises an electric energy storage unit, which is electrically connected to the power source and to the carbon dioxide storage unit, in particular to the liquefaction unit. The electric energy storage unit is configured to receive and store electrical energy from the power source and to provide the stored electric energy to the carbon dioxide storage unit, in particular to the liquefaction unit, during operation of the carbon dioxide storage unit. These embodiments allow electric energy to be supplied to the liquefaction unit even during electric energy supply intermittencies, which allows the liquefaction to continue running and thereby increases storage efficiency and minimizes carbon dioxide emission, ultimately contributing to a low product carbon footprint.

[0102] Optionally, the electric energy storage unit may further be electrically connected to the carbon dioxide source and / or to the fuel production unit. For example, the electric energy storage unit may also be used to power a biogas plant (or any other carbon dioxide source) during its operation. This allows e.g. carbon dioxide generate to continue running despite any possible intermittencies of the electric energy source.

[0103] Depending on the application, the facility may utilize different carbon dioxide sources. It is understood that the choice of carbon dioxide source may be made independent of whether or not the facility comprises an electric energy storage unit as described above.P29215PC00

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[0105] In a typical embodiment, the carbon dioxide source is configured to generate carbon dioxide essentially continuously. One advantage of continuous carbon dioxide generation is that many carbon dioxide sources that allow cheap carbon dioxide generation tend to operate continuously. For example, while a batch-wise supply from bottled carbon dioxide is conceivable, it tends to be more costly in overall operating expenditure than continuous carbon dioxide generation e.g. through a biogas plant. Furthermore, utilizing a biogas plant as carbon dioxide plant allows to realize the synergy of concomitant biogas generation.

[0106] Additionally, carbon dioxide capture plants may also be used as carbon dioxide source. For example, the carbon dioxide capture plant may be configured to capture carbon dioxide directly from air and / or from flue gas or other gas mixtures having a carbon dioxide content of at least 1%, preferably at least 5%. Thus, in some embodiments, the carbon dioxide source comprises one or more of the following:

[0107] - a biogas plant configured to produce and provide carbon dioxide as input for the fuel production reactor; and / or

[0108] - a carbon dioxide capture plant configured to produce and provide carbon dioxide as input for the fuel production reactor; and / or

[0109] - a biomass power plant; and / or

[0110] - a bioethanol plant.

[0111] In the case of the biomass plant, the biomass power plant is typically configured to burn biomass, thereby generating the carbon dioxide. It is understood that a biomass power plant may be used as part of the facility of the present disclosure as carbon dioxide source and / or as a power plant.P29215PC00

[0112] 22 / 41

[0113] In the case of the bioethanol plant, the bioethanol plant is typically configured to ferment biomass (e.g. wheat, corn, sugarcane, etc.), thereby generating ethanol and carbon dioxide.

[0114] In preferred embodiments, the carbon dioxide source comprises the biogas plant and / or the carbon dioxide capture plant.

[0115] It is understood that depending on the carbon dioxide source, the carbon dioxide generated by the carbon dioxide source may have different carbon dioxide concentrations or purities. For example, in some embodiments, the carbon dioxide generated by the carbon dioxide source consists of essentially pure carbon dioxide. However, it is also possible for the generated carbon dioxide to contain impurities and / or other gases (or liquids, depending on the pressure and temperature), particularly other gases that are inert in the subsequent fuel production. As an example, the carbon dioxide source may e.g. generate a mixture of carbon dioxide and nitrogen and / or methane. For example, e.g. when using a biogas plant as carbon dioxide source, the biogas plant may generate a mixture of carbon dioxide and methane. This mixture may then be supplied to the fuel production unit as a mixture, or the mixture may first be separated before supplying the separated carbon dioxide to the fuel production unit. These embodiments illustrate that in general, the carbon dioxide generated by the carbon dioxide source may be generated either as essentially pure carbon dioxide, or as a mixture comprising carbon dioxide. The carbon dioxide concentration in this mixture may vary, depending on the carbon dioxide source. In some embodiments, the mixture comprises at least 1 vol.-% carbon dioxide, preferably at least 10 vol.-% carbon dioxide, more preferably at least 30 vol.-% carbon dioxide. In some embodiments, the mixture comprises at least 50 vol.-%, such as at least 75 vol.-%, e.g. at least 90 vol.-% or even at least 95 vol.-% carbon dioxide.P29215PC00

[0116] 23 / 41

[0117] Depending on the application and on the carbon dioxide source utilized, the carbon dioxide generated from the carbon dioxide source may optionally be pre-treated before being supplied to the fuel production unit and / or to the carbon dioxide storage unit. For example, such a pre-treatment may involve purification steps such as desulfurization and / or removal of other impurities, including trace impurities, and / or physical pre-treat-ment such as compression and / or temperature adjustment.

[0118] Thus, in some embodiments, the facility further comprises a carbon dioxide processing unit arranged downstream of the carbon dioxide source and upstream of the fuel production unit. The carbon dioxide processing unit comprises:

[0119] - A / the carbon dioxide pre-treatment unit configured for purifying the generated carbon dioxide from the carbon dioxide source; and / or

[0120] - One or more carbon dioxide compressors configured for compressing the generated carbon dioxide from the carbon dioxide source, preferably to a pressure of at least 2 bar, more preferably to a pressure from 5 bar to 15 bar.

[0121] If both the carbon dioxide pre-treatment unit and the carbon dioxide compressor are provided, the carbon dioxide compressor is preferably arranged downstream of the carbon dioxide pre-treatment unit. Irrespective of its location, the carbon dioxide compressor may in some embodiments be configured for compressing the generated carbon dioxide from the carbon dioxide source together with excess carbon dioxide from the carbon dioxide storage unit and / or together with hydrogen from the hydrogen source. For example, the generated carbon dioxide from the carbon dioxide source (optionally together with the excess carbon dioxide and / or together with the hydrogen) may be compressed to a pressure of at least 2 bar, preferably from 5 bar to 20 bar, such as 10 bar.P29215PC00

[0122] 24 / 41

[0123] Furthermore, depending on the application, where excess carbon dioxide is supplied to the carbon dioxide storage unit, it may optionally be branched off at different locations. For example, in some embodiments, the excess carbon dioxide may be supplied from the carbon dioxide source to the carbon dioxide storage unit directly. However, in preferred embodiments, the excess carbon dioxide is supplied from the carbon dioxide source to the carbon dioxide storage unit through intermediacy of the carbon dioxide pretreatment unit. For example, the carbon dioxide pre-treatment unit may constitute a branch-off point where at least some of the pre-treated carbon dioxide is supplied to the fuel production unit for fuel production and excess carbon dioxide is supplied to the carbon dioxide storage unit for storage. It is understood that eventually, the stored excess carbon dioxide may be supplied to the fuel production unit. In some embodiments, essentially all of the carbon dioxide generated by the carbon dioxide source is supplied to the pre-treatment unit for pre-treatment.

[0124] Irrespective of the exact locations in flow direction, the carbon dioxide pre-treatment may optionally comprise water condensation (e.g. to remove at least some residual water in the generated carbon dioxide from the carbon dioxide source) and / or purification, such as desulfurization and / or NOXremoval and / or amine removal and / or ammonia removal. The carbon dioxide pre-treatment may also be chosen in accordance with the carbon dioxide source. For example, where a carbon dioxide capture plant is utilized which relies on amines to capture the carbon dioxide, the pre-treatment preferably involves amine removal.

[0125] Depending on the application and on the type of fuel to be produced, different raw materials may be used. In some embodiments, the fuel is produced at least from carbon dioxide and hydrogen. For example, carbon dioxide and hydrogen may be subjected to the Sabatier process to generate methane. The hydrogen may be provided from different sources, such as electrolysis. More generally, in some embodiments, the fuel productionP29215PC00

[0126] 25 / 41

[0127] unit further comprises a / the hydrogen source configured to generate hydrogen and to supply the generated hydrogen to the fuel production reactor for fuel production. Preferably, the hydrogen source comprises one or more electrolysis units. The hydrogen source may e.g. be powered by the power source. It is understood that the electrolysis units are typically configured to electrolyze water to generate hydrogen (and also oxygen).

[0128] According to a second aspect of the present disclosure, a process for producing fuel, preferably methane and / or methanol, is provided. The process comprises the steps of:

[0129] - Generating carbon dioxide in a carbon dioxide source;

[0130] - Supplying, during operation of a fuel production unit, at least some of the generated carbon dioxide from the carbon dioxide source to the fuel production unit;

[0131] - Producing the fuel in a fuel production reactor of the fuel production unit;

[0132] - Supplying, during a period of carbon dioxide underdemand from the fuel production unit, excess carbon dioxide from the carbon dioxide source to a carbon dioxide storage unit.

[0133] It is understood that the facility of the first aspect of the present disclosure and the process of the second aspect are inherently intertwined with each other. In particular, the process of the second aspect can be operated using the facility of any one of the embodiments of the first aspect described herein. Therefore, the embodiments described herein in the context of the facility of the first aspect are also embodiments of the process of the second aspect, unless specifically stated otherwise or unless the context clearlyP29215PC00

[0134] 26 / 41

[0135] dictates otherwise. This means that each feature and any respective advantage disclosed or described with respect to the facility is also applicable mutatis mutandis to the above disclosed aspect of the process.

[0136] In some embodiments, the process further comprises the step of liquefying, in a liquefying unit of the carbon dioxide storage unit, at least a portion of the excess carbon dioxide; and storing, in a storage tank of the carbon dioxide storage unit, at least a portion of the liquefied excess carbon dioxide.

[0137] In some embodiments, the process further comprises the step of supplying, during a period of carbon dioxide overdemand from the fuel production unit, at least some of the stored excess carbon dioxide from the carbon dioxide storage unit to the fuel production unit for fuel production during operation of the fuel production unit.

[0138] As explained in further detail above, the water content of carbon dioxide from the carbon dioxide source and from the carbon dioxide storage unit may differ. For example, in some embodiments, during the period of carbon dioxide overdemand from the fuel production unit, the stored excess carbon dioxide supplied to the fuel production unit from the carbon dioxide storage unit and the generated carbon dioxide supplied to the fuel production unit from the carbon dioxide source have different water contents.

[0139] Alternatively or in combination, in some embodiments, the generated carbon dioxide supplied to the fuel production unit from the carbon dioxide source has a lower water content during the period of carbon dioxide underdemand from the fuel production unit than during the period of carbon dioxide overdemand from the fuel production unit.

[0140] In some embodiments, the process is performed using the facility of any one of the embodiments described herein.P29215PC00

[0141] 27 / 41

[0142] Depending on the application, photovoltaic or other inherently intermittent power sources may be used. In some embodiments, the method comprises supplying, during a period of sunshine, carbon dioxide from the carbon dioxide source to the fuel production unit. Alternatively or in combination, in some embodiments, the method comprises supplying, during a period of limited or no sunshine, at least a portion of the carbon dioxide generated by the carbon dioxide source from the carbon dioxide source to the carbon dioxide storage unit.

[0143] 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.

[0144] BRIEF DESCRIPTION OF THE DRAWINGS

[0145] 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:

[0146] Fig. 1 a schematic view of a variant of a facility for producing fuel;

[0147] Fig. 2 a flow diagram illustrating schematically a plurality of steps of one embodiment of the fuel production process described herein.P29215PC00

[0148] 28 / 41

[0149] DESCRIPTION OF THE EMBODIMENTS

[0150] 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.

[0151] Figure 1 shows a schematic view of a variant of facility 1 for producing fuel 2. The illustrated variant is a methanation facility for producing methane from carbon dioxide and hydrogen. The facility 1 comprises a fuel production unit 3 which comprises a fuel production reactor 31. The fuel production reactor 31 may e.g. by a honeycomb reactor. The fuel production unit 3 further comprises a hydrolysis unit 11 acting as hydrogen source for generating hydrogen 111 and supplying hydrogen 111 to the methanation reactor 31 , either directly (as shown), or indirectly through a compressor (not shown but described below). The fuel production unit 3, and in particular the electrolysis unit 11 of the fuel production unit 3, is powered by a power source 9, such as a photovoltaic power plant or any other renewable power plant such as a wind power plant, a biogas power plant and / or a hydroelectric power plant.

[0152] The facility 1 also includes a biogas plant (i.e. a biogas fermentation plant) acting as carbon dioxide source 4, which continuously generates carbon dioxide 5. The generated carbon dioxide 5 typically contains residual water and impurities, such as sulfur or sulfides, and potentially also trace impurities such as mercury. Thus, the generated carbon dioxide 5 is first supplied from the biogas plant to a carbon dioxide processing unit 7, specifically to a carbon dioxide pre-treatment unit 72 of the carbon dioxide processing unit 7. In the carbon dioxide pre-treatment unit 72, the generated carbon dioxide 5 isP29215PC00

[0153] 29 / 41

[0154] purified by condensing the residual water and by desulfurization. After this pre-treatment, the further fate of the generated, pre-treated carbon dioxide depends on a range of different factors relating to the balance of input parameters and input resources used in the fuel production. For example, during operation of the fuel production unit 3, at least some of the generated, pre-treated carbon dioxide 51 is supplied from the carbon dioxide pretreatment unit to the fuel production unit 3 for fuel production. More specifically, the generated, pretreated carbon dioxide 51 is first supplied to a carbon dioxide compressor 71 of the carbon dioxide processing unit 7 in which the carbon dioxide is compressed, typically to a pressure of 10 bar, before the compressed carbon dioxide is supplied to the fuel production reactor. Optionally, the hydrogen 111 generated by the electrolysis unit 11 may also be sent to the compressor and be compressed together with the carbon dioxide (not shown).

[0155] Alternatively, if the carbon production unit 3 is not in operation, or if at least the methana-tion in the fuel production reactor 31 is not operated or only operated at reduced rates, the excess carbon dioxide 52 is supplied from the carbon dioxide pre-treatment unit 72 to a carbon dioxide storage unit 6 for (preferably temporary) storage. More specifically, the excess carbon dioxide 52 is initially supplied to a liquefaction unit 61 in which the excess carbon dioxide 52 is liquefied. Subsequently, the liquefied carbon dioxide is supplied to a storage tank 62 in which the liquefied carbon dioxide is (preferably temporarily) stored.

[0156] It would be conceivable to store the liquefied carbon dioxide permanently or to bottle the liquefied carbon dioxide and sell it in bottled form. However, in preferred variants, at least a portion of the liquefied excess carbon dioxide is supplied directly or indirectly to the fuel production unit, e.g. to overcome carbon dioxide overdemand periods in which the carbon dioxide demand from the fuel production unit 31 exceeds the supply of carbon dioxide generated by the carbon dioxide source 4. Such a situation may e.g. arise inP29215PC00

[0157] 30 / 41

[0158] cases of an unusually high workload of the fuel production unit 3 and / or in cases where the carbon dioxide source 4 produces less carbon dioxide than usual, e.g. due to a maintenance outage. The carbon dioxide supply from the carbon dioxide source 4 may also be deliberately reduced in order to allow the liquefied excess carbon dioxide to be fed back into the system, e.g. to generate new storage capacity in the carbon dioxide storage. Regardless of the reason for the mismatch between carbon dioxide demand from the fuel production unit 3 and carbon dioxide supply from the carbon dioxide source 4, when the liquefied excess carbon dioxide is supplied to the fuel production unit 3, it is preferably first supplied to an evaporation unit 63 in which it is evaporated, and the evaporated excess carbon dioxide is then supplied to the fuel production reactor 31. Alternatively or in combination, it is also possible to supply the evaporated excess carbon dioxide to the carbon dioxide compressor 71, where it may be mixed with carbon dioxide generated directly by the carbon dioxide source 51.

[0159] In figure 1, generally, material transport streams are indicated by dashed arrows with short dashes. By contrast, the dashed arrows with longer dashes indicate electricity transfer. The through-going lines interconnecting the control unit 10 with other units indicate the flow of information and operative instructions and lastly, the through-going, fat arrows indicate thermal heat transfers.

[0160] As an illustrative example of the process and facility described in figure 1, carbon dioxide supply-demand mismatches may occur where an energy source that suffers from energy intermittencies is used, such as a photovoltaic power plant. When the sun shines and electricity is available, electricity is provided to the fuel production unit 3 to power in particular the hydrogen production by the electrolysis unit 11. Consequently, the methana-tion reactor 31 is operated and in turn requires carbon dioxide as raw material, thereby defining a specific carbon dioxide demand. The carbon dioxide demand can be satisfiedP29215PC00

[0161] 31 / 41

[0162] by the carbon dioxide supply from the carbon dioxide source 4 in the form of the generated carbon dioxide. If this supply is insufficient, additional carbon dioxide can be supplied to the fuel production unit 3 by the carbon dioxide storage unit 6. By contrast, when the sun no longer shines, no electricity is available anymore and the fuel production unit 3 may operate at lower levels or even experience a downtime, resulting in diminished or even no carbon dioxide demand from the fuel production unit 3. However, if the carbon dioxide source 4 continues to produce carbon dioxide, excess carbon dioxide is generated, which may then be supplied to the carbon dioxide storage unit 6.

[0163] The process may be controlled by a control unit 10 which, in the illustrated variant, is operably connected to the fuel production unit 3, to the carbon dioxide processing unit 7, to the carbon dioxide source 4 and to the carbon dioxide storage unit 6.

[0164] Furthermore, the facility 1 may optionally further comprise a battery 13 electrically interconnected to the power source 9. The battery 13 may e.g. be loaded by the power source 9 (e.g., in the case of a photovoltaic power plant, when the sun shines), and may then be used to power the carbon dioxide storage unit 6, in particular the liquefaction unit 61 , especially in time periods in which the power source 9 does not generate any power or only insufficient amounts of power (e.g., in the case of a photovoltaic power plant, when the sun no longer shines).

[0165] Lastly, the illustrated facility 1 also comprises a heat exchanger 8, which makes the facility and the operation process particularly efficient. The heat exchanger 8 thermally interconnects the evaporation unit 63 (which generates cold, i.e. negative heat, upon evaporation of the liquefied excess carbon dioxide) with different cold consumers, i.e. heat generators. As illustrated, the heat generators may e.g. include the carbon dioxide pre-treatment unit 72, particularly the condensation unit of the pre-treatment unit 72, the carbon dioxide compressor 71 , and a fuel condensation unit 14 for condensation of waterP29215PC00

[0166] 32 / 41

[0167] out of the fuel 2 generated by the fuel production reactor 31 (to ensure that the methane does not exceed the water threshold levels required for feeding it to the methane grid 12).

[0168] Depending on the application, different methanation reactors may be used. For example, 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 through the channels and react in the channels with the catalyst coating. The reaction zone is therefore within the channels. For example, DE 10 2016 125 641 A1 discloses a process for production of a natural gas substitute from hydrogen-containing gas mixtures using a reactor with channels.

[0169] Figure 2 shows a flow diagram illustrating schematically a plurality of steps of one embodiment of the fuel production process described herein. The process may in particular be carried out using the facility described herein, e.g. the specific variant of the facility described in the context of figure 1.

[0170] In general, the process commences with generating carbon dioxide in a carbon dioxide source in step S1. Subsequently, at least some of the generated carbon dioxide is supplied to a fuel production unit in step S2 during operation of the fuel production unit. Subsequently, fuel is produced by a fuel production reactor of the fuel production unit in step S3.

[0171] As described above, there can be instances where the carbon dioxide supply from the carbon dioxide source exceeds the carbon dioxide demand from the fuel production unit.P29215PC00

[0172] 33 / 41

[0173] Thus, during a period of carbon dioxide underdemand from the fuel production unit, excess carbon dioxide is supplied from the carbon dioxide source to a carbon dioxide storage unit in step S4. After being supplied, the excess carbon dioxide is then liquefied in a liquefaction unit of the carbon dioxide storage unit in step S5. The liquefied excess car-bon dioxide is then stored in a storage tank of the carbon dioxide storage unit in step S6. The stored liquefied excess carbon dioxide may e.g. ultimately be used for fuel production. As described in further detail above, there can be instances where the carbon dioxide demand from the fuel production unit exceeds the carbon dioxide supply from the carbon dioxide source. Thus, during a period of carbon dioxide overdemand from the fuel production unit, at least some of the stored excess carbon dioxide is supplied to the fuel production unit for fuel production during operation of the fuel production unit in step S7.P29215PC00

[0174] 34 / 41

[0175] LIST OF DESIGNATIONS

[0176] 1 Facility for producing fuel 8 Heat exchanger

[0177] 2 Fuel 9 Power source

[0178] 3 Fuel production unit 10 Control unit

[0179] 31 Fuel production reactor 25 11 Electrolysis unit

[0180] 4 Carbon dioxide source 111 Hydrogen

[0181] 5 Carbon dioxide generated by 12 Methane grid

[0182] carbon dioxide source 13 Battery

[0183] 51 Portion of generated carbon di14 Fuel condensation unit oxide supplied to the fuel production unit 30 51 Generating

[0184] 52 Excess carbon dioxide supplied 52 Supplying generated carbon difrom the carbon dioxide source to the oxide to the fuel production unit carbon dioxide storage unit 53 Producing

[0185] 6 Carbon dioxide storage unit 54 Supplying excess carbon dioxide 61 Liquefaction unit 35 to the carbon dioxide storage unit 62 Storage tank 55 Liquefying

[0186] 63 Evaporation unit 56 Storing

[0187] 7 Carbon dioxide processing unit 57 Supplying stored excess carbon 71 Carbon dioxide compressor dioxide to the fuel production unit for fuel 72 Carbon dioxide pre-treatment 40 production

[0188] unit

Claims

P29215PC0035 / 41PATENT CLAIMS1. Facility (1) for producing fuel (2), the facility (1) comprising:- A fuel production unit (3) comprising a fuel production reactor (31) configured to produce the fuel (2);- A carbon dioxide source (4) configured to generate carbon dioxide and to supply at least some of the generated carbon dioxide (51) to the fuel production unit (3) for fuel production during operation of the fuel production unit (3), wherein the carbon dioxide source (4) is further configured to supply, during a period of carbon dioxide underdemand from the fuel production unit (3), excess carbon dioxide (52) to a carbon dioxide storage unit of the facility (1);- Wherein the carbon dioxide storage unit (6) comprises:i. A liquefaction unit (61) for liquefying at least some of the excess carbon dioxide (52); andii. A storage tank (62) arranged downstream of the liquefaction unit (61) and configured to store the liquefied excess carbon dioxide.

2. The facility (1) according to claim 1 , wherein the carbon dioxide storage unit (6) is configured to supply, during a period of carbon dioxide overdemand from the fuel production unit (3), at least some of the stored excess carbon dioxide to the fuel production unit (3) for fuel production during operation of the fuel production unit (3).P29215PC0036 / 413. The facility (1) according to claim 2, wherein the carbon dioxide storage unit (6) is configured to supply at least some of the stored excess carbon dioxide to the fuel production unit (3) directly and / or through intermediacy of a carbon dioxide processing unit (7) arranged in flow direction between the carbon dioxide storage unit (6) and the fuel production unit (3).

4. The facility (1) according to any one of claims 2 or 3, wherein the carbon dioxide storage unit (6) further comprises an evaporation unit (63) arranged downstream of the storage tank (62) and upstream of the fuel production unit (3), wherein the evaporation unit (63) is configured to evaporate the liquefied excess carbon dioxide and to supply the evaporated excess carbon dioxide to the fuel production unit (3), optionally through intermediacy of the carbon dioxide processing unit (7).

5. The facility (1) according to claim 4, further comprising a heat exchanger (8) thermally connecting the evaporation unit (63) to one or more heat suppliers for cooling the one or more heat suppliers.

6. The facility (1) according to claim 5, wherein the one or more heat suppliers comprise one or more of the following:- The fuel production reactor (31);- One or more carbon dioxide compressors (71) of a / the carbon dioxide processing unit (7);A carbon dioxide pre-treatment unit (72) of a / the carbon dioxide processing unit (7);A / the one or more electrolysis units;P29215PC0037 / 41- A hydrogen condensation unit for condensation of water out of a hydrogen stream generated by the one or more electrolysis units.

7. The facility (1) according to any one of the previous claims, wherein the fuel production reactor (31) is configured to produce a hydrocarbon fuel and / or methanol, preferably methane and / or methanol, more preferably methane.

8. The facility (1) according to any one of the previous claims, further comprising a power source (9) configured to provide electric energy to the fuel production unit (3) during its operation;9. The facility (1) according to claim 8, wherein the power source (9) is a power plant configured to generate electric energy which is at least partially provided to the fuel production unit (3) during its operation, wherein the power plant is preferably a renewable energy power plant, in particular at least one of: a photovoltaic power plant, a wind power plant, a biogas power plant, a biomass power plant or a hydroelectric power plant, preferably a photovoltaic power plant.

10. The facility (1) according to any one of the previous claims, further comprising a control unit (10) configured to:- Compare a carbon dioxide supply level from the carbon dioxide source (4) to a carbon dioxide demand level from the fuel production unit (3);- Wherein if the carbon dioxide supply level exceeds the carbon dioxide demand level, the control unit (10) is configured to instruct the carbon dioxide source (4) to supply at least some of the excess carbon dioxide to the carbon dioxide storage unit (6) for storage; andP29215PC0038 / 41- Wherein if the carbon dioxide demand level exceeds the carbon dioxide supply level, the control unit (10) is configured to instruct the carbon dioxide storage unit (6) to supply at least some of the stored excess carbon dioxide to the fuel production unit (3).

11. The facility (1) according to claim 10, wherein the control unit (10) is further configured to determine the carbon dioxide demand level from the fuel production unit (3) based on an electricity supply level input from the power source (9) and / or based on a hydrogen supply level input from a hydrogen source (11) of the fuel production unit (3).

12. The facility (1) according to any one of the previous claims, wherein the carbon dioxide source (4) comprises one or more of the following:- a biogas plant configured to produce and provide carbon dioxide as input for the fuel production reactor (31); and / or- a carbon dioxide capture plant configured to produce and provide carbon dioxide as input for the fuel production reactor (31).

13. The facility (1) according to any one of the previous claims, wherein the facility (1) further comprises a / the carbon dioxide processing unit (7) arranged downstream of the carbon dioxide source (4) and upstream of the fuel production unit (3), wherein the carbon dioxide processing unit (7) comprises:- A / the carbon dioxide pre-treatment unit (72) configured for purifying the generated carbon dioxide from the carbon dioxide source (4); and / orP29215PC0039 / 41- One or more carbon dioxide compressors (71) configured for compressing carbon dioxide from the carbon dioxide source (4), preferably to a pressure of at least 2 bar;14. A process for producing fuel, preferably methane and I or methanol, the method comprising the steps of:- Generating (S1) carbon dioxide in a carbon dioxide source (4);- Supplying (S2), during operation of a fuel production unit (3), at least some of the generated carbon dioxide from the carbon dioxide source (4) to the fuel production unit (3);- Producing (S3) the fuel in a fuel production reactor (31) of the fuel production unit (3); and- Supplying (S4), during a period of carbon dioxide underdemand from the fuel production unit (3), excess carbon dioxide from the carbon dioxide source (4) to a carbon dioxide storage unit (6);Wherein the method preferably further comprises the steps of:- Liquefying (S5), in a liquefying unit of the carbon dioxide storage unit (6), at least a portion of the excess carbon dioxide; and- Storing (S6), in a storage tank (62) of the carbon dioxide storage unit (6), at least a portion of the liquefied excess carbon dioxide.

15. The process according to claim 14, further comprising the step of:P29215PC0040 / 41- Supplying (S7), during a period of carbon dioxide overdemand from the fuel production unit (3), at least some of the stored excess carbon dioxide from the carbon dioxide storage unit (6) to the fuel production unit (3) for fuel production during operation of the fuel production unit (3).

16. The process according to any one of claims 14-15, wherein the process is performed using the facility (1) of any one of claims 1-13.

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