Method and system for preparation of fischer-tropsch based raw products for the production of preformulated or standard fuels

Abstract

The invention relates to methods and devices for producing fuels conforming to standards, preferably gasoline (according to EN 228), diesel (according to EN 590 or EN 15940) and kerosene (according to ASTM D7566 or ASTM D1566), proceeding from CO2 and H2 by means of an integrated preparation of Fischer-Tropsch raw products using different method steps, in which hydrogen or gases containing hydrogen, which remain after the preparation, are returned into RWGS before the Fischer-Tropsch synthesis.

Description

[0001] The present invention relates to processes and systems for the production of standard-compliant fuels, such as diesel or kerosene, by means of an integrated processing of the Fischer-Tropsch raw products (in particular oil and wax) through various process steps and corresponding systems. State of the art:

[0002] The Fischer-Tropsch synthesis (FTS) process, used to produce hydrocarbons, has been known for many decades. In this process, synthesis gas, consisting primarily of carbon monoxide (CO) and hydrogen (H₂), is converted to hydrocarbons through heterogeneous catalysis in a synthesis reactor. The output stream of Fischer-Tropsch synthesis units, in which synthesis gas is synthesized into hydrocarbons using the Fischer-Tropsch process, typically contains four fractions: A gas phase consisting of unreacted synthesis gas (mainly CO, H₂), short-chain hydrocarbons, and volatile components of the byproducts, as well as CO₂. A waxy phase of long-chain hydrocarbons that is solid at ambient temperature and pressure (wax phase). A hydrophobic phase of shorter-chain hydrocarbons that is liquid at ambient temperature and pressure (oil phase). An aqueous phase consisting of the water of reaction formed and dissolved organic compounds. Processes are known in which the wax and oil phases produced by the Fischer-Tropsch synthesis are refined into standardized fuel products such as gasoline, diesel, or kerosene by hydrogen treatment using so-called hydrotreatment in refineries.

[0003] WO 2007 / 031668 A1 describes the recirculation of gases from the upgrading unit into the Fischer-Tropsch reactor; the recycled gases are fed directly into the Fischer-Tropsch stage. US 6,306,917 B1 describes the recirculation of hydrotreatment gases into synthesis gas production, with gas purification being provided. US 8,106,102 B2 describes the recirculation of hydrogen from hydrotreatment into the Fischer-Tropsch stage. WO 2004 / 096952 A1 describes the recycling of gases from the processing stage using separation stages. DE 10 2019 200245 A1 discloses the separation of Fischer-Tropsch products and the recirculation of the gaseous components into a reformer.

[0004] One problem with the current state of the art is that decentralized, climate-neutral energy generation concepts often rely on the direct on-site conversion of renewable energy into liquid and / or solid energy carriers with high energy densities for loss-reducing transport or intermediate storage. Fuel-oriented use of these climate-neutral energy carriers subsequently requires processing into standard-compliant fuels, which usually takes place in refineries. However, conventional refinery processing relies on very high throughputs, which only allows for so-called co-processing of the throughput-limited, decentralized Fischer-Tropsch products. This only results in the possibility of a climate-neutral blending rate of the refinery product.To produce a completely climate-neutral fuel according to the current state of the art, either the construction of a refinery adapted to the production capacity of the Fischer-Tropsch synthesis is necessary, or a direct, decentralized processing of the Fischer-Tropsch raw products into standard-compliant fuels.

[0005] Furthermore, according to the current state of the art, it is problematic that conventional and already extensively researched processing methods such as hydrocracking, hydrogenation, and isomerization require a very high input of hydrogen. For economic reasons, these processes are therefore often coupled with hydrogen production processes in conventional oil refineries. The high hydrogen demand would make the construction of a standalone processing plant for Fischer-Tropsch products into standard-compliant fuels increasingly difficult to operate economically.

[0006] Therefore, based on the current state of the art, there is still considerable potential for improvement. Task:

[0007] The object of the present invention was therefore to provide methods and devices which no longer exhibit the problems of the prior art, or at least only to a greatly reduced extent, or which exhibit new advantageous effects.

[0008] Further tasks arise from the following description. Solution:

[0009] These and other problems are solved within the scope of the present invention by the subject matter of the independent claims.

[0010] Preferred configurations result from the dependent claims and the following description. Definitions of terms:

[0011] Within the scope of the present invention, all quantity specifications, unless otherwise stated, are to be understood as weight specifications.

[0012] Within the scope of the present invention, the term "ambient temperature" means a temperature of 20°C. Unless otherwise specified, temperature readings are in degrees Celsius (°C).

[0013] Unless otherwise stated, the reactions or process steps listed are carried out at ambient pressure (=normal pressure / atmospheric pressure), i.e. at 1013 mbar a .

[0014] Within the scope of the present invention, the term "long-chain hydrocarbons" refers to hydrocarbons with at least 25 carbon atoms (C₂₅). These long-chain hydrocarbons with at least 25 carbon atoms can be linear or branched. Typically, long-chain hydrocarbons reach chains of approximately 100 carbon atoms. Even longer chains can be formed under specific reaction conditions.

[0015] Within the scope of the present invention, the term "shorter-chain hydrocarbons" refers to hydrocarbons with 5 to 24 carbon atoms (C₅-C₂₄). These shorter-chain hydrocarbons with 5 to 24 carbon atoms can be linear or branched.

[0016] Within the scope of the present invention, the term "short-chain hydrocarbons" refers to hydrocarbons with 1 to 4 carbon atoms (C1-C4). The short-chain hydrocarbons with 4 carbon atoms can be linear or branched.

[0017] Within the scope of the present invention, the term "wax phase" refers to the product phase of the Fischer-Tropsch synthesis characterized by long-chain hydrocarbons. In some cases, it may contain minor amounts of other compounds in amounts of less than 10% by weight, and in particular less than 5% by weight. This is known to those skilled in the art and requires no further explanation.

[0018] Within the scope of the present invention, the term "oil phase" refers to the product phase of the Fischer-Tropsch synthesis characterized by shorter-chain hydrocarbons. In some cases, it may contain minor amounts of other compounds in amounts of less than 10% by weight, and in particular less than 5% by weight. This is known to those skilled in the art and requires no further explanation.

[0019] Within the scope of the present invention, "standard-compliant fuels" are understood to mean those fuels that can be used in compliance with the respective legal standards, i.e., that meet the parameters of the respective standards. This may vary depending on the currently applicable legal regulations. In particular, such standards are EN 228 for gasoline, EN 590 or EN 15940 for diesel, and ASTM D7566 or ASTM D1566 for kerosene.

[0020] For the sake of simplicity, "Fischer-Tropsch" is occasionally abbreviated to "FT" within the scope of the present invention.

[0021] Within the scope of the present invention, "ReverseWaterGasShift reaction" is occasionally abbreviated to "RWGS" for the sake of simplicity, and the device / unit in which the RWGS takes place is also occasionally referred to as "RWGS" for the sake of simplicity.

[0022] Within the scope of the present invention, "hydrotreatment unit" is occasionally abbreviated as "HTE" for the sake of simplicity.

[0023] Within the scope of the present invention, the terms "plant" and "device" are occasionally used synonymously.

[0024] Within the scope of the present invention, a power-to-liquid (PtL) plant or a power-to-liquid process in the narrower sense is understood to be a plant or a process in which CO2 is converted together with hydrogen, in particular electrolytically produced hydrogen, into the target products oil phase and wax phase, wherein, in addition to the target products, a gas fraction with light, short-chain hydrocarbons (C1-C4) and residual gases (CO, CO2, H2) as well as an aqueous phase with dissolved oxygen-containing hydrocarbons (by-products including alcohols, organic acids) may also be formed.

[0025] In a broader sense, this also includes the subsequent processing or reprocessing unit of the wax and / or oil phase into standard-compliant fuels.

[0026] Within the scope of the present invention, the term "consisting of" is to be interpreted as referring to essential parts of a device or essential steps of a method. It is understood that common parts such as screws, pipe connectors, couplings, and so on may (or must) be present, even if they are not explicitly mentioned. Detailed description:

[0027] The present invention relates to methods and devices for the production of standard-compliant fuels, preferably gasoline (according to EN 228), diesel (according to EN 590 or EN 15940) and kerosene (according to ASTM D7566 or ASTM D1566), particularly preferably diesel or kerosene, by an integrated processing of the Fischer-Tropsch raw products (oil and wax) via various process steps.

[0028] In some variants of the present invention, the synthesis gas as the starting point for the Fischer-Tropsch synthesis originates from the gasification of biomass, from synthesis gas production from fossil feedstocks (natural gas, petroleum, coal) or from electricity-based processes (conversion of electrolytically produced H2 and CO2 into storable products).

[0029] The FT synthesis unit to be used in the present invention is generally based on two successively arranged stages: in the first stage an RWGS (reverse water gas shift) reaction takes place and in the second the actual FT conversion.

[0030] In the RWGS process, carbon dioxide (CO₂) reacts with hydrogen (H₂) to form carbon monoxide (CO) and water (H₂O). In preferred embodiments of the present invention, the hydrogen is not completely converted in order to be used as a reactant in the subsequent FT unit. Therefore, H₂ is preferably introduced into the RWGS in excess.

[0031] The synthesis gas obtained in the RWGS can, within the scope of the present invention, comprise not only CO and H₂ or CO, H₂O and H₂, but also CO₂ and CH₄, and potentially further impurities. This is particularly true if the gas recycled from the work-up process contains C₁ to C₄ hydrocarbons in addition to hydrogen.

[0032] The mixture consisting of CO and H2 or CO, H2O and H2 produced during RWGS is then fed into the FT unit as a reactant stream.

[0033] By extending the Fischer-Tropsch synthesis unit with an additional, independent processing stage, which in some embodiments of the present invention includes conventional processing steps such as hydrocracking, hydrogenation, isomerization and fractionation, the FT product can be processed directly at the location of the FT synthesis unit into standard-compliant fuels, thus enabling direct use.

[0034] To minimize the high hydrogen demand in the processing stage, this unit is coupled to the Fischer-Tropsch synthesis unit within the scope of the present invention, and the processing exhaust gas is utilized in the RWGS (recycled gas return system) of the Fischer-Tropsch synthesis unit. This process reduces the hydrogen feed to the Fischer-Tropsch unit, as unreacted hydrogen from the processing plant is recycled via the RWGS to the inlet of the FT unit. This allows for the efficient generation of the necessary excess hydrogen for the processing reactions. Thus, the FT unit is partially supplied with feed gas via the coupled processing unit.

[0035] In the present invention, the exhaust gases from the processing unit are fed into the synthesis gas production process in this circuit. This addresses the problem that a high H₂ content is also necessary here to convert the supplied CO₂ into carbon monoxide.

[0036] In the present invention, this synthesis gas production is effected by a reverse water-gas shift (RWGS) reaction.

[0037] In contrast to the prior art, the present invention uses the hydrogen-containing exhaust gases from the HT unit to produce synthesis gas in an RWGS.

[0038] Accordingly, within the scope of the present invention, recycled gases are added to the synthesis gas production process.

[0039] Within the scope of the present invention, purification is not necessary when the hydrotreatment exhaust gases are recycled into synthesis gas production; in particular, no separation stages are necessary.

[0040] A special feature of the present invention is the direct introduction of the hydrogen-containing exhaust gases from the hydrotreatment into the RWGS.

[0041] By directly introducing the exhaust gases, various gas separation devices can be avoided within the scope of the present invention. At the same time, the use of (fresh) hydrogen in the RWGS can be significantly reduced, since the concentration of hydrogen in the hydrotreatment unit is very high and the conversion rate is relatively low.

[0042] Within the scope of the present invention, it has been shown that the circuitry and method according to the invention produce particularly advantageous results.

[0043] Within the scope of the present invention, the hydrotreatment unit comprises, in some embodiments, at least hydrocracking, hydrogenation, and isomerization as various processing steps. This enables the production of standard-compliant fuels such as diesel or kerosene from the products discharged from a Fischer-Tropsch plant.

[0044] A preferred embodiment of the present invention can be described as follows: The wax phase extracted from the FT synthesis is conveyed to a feed tank of the hydrotreatment unit (HTE) and from there, together with added hydrogen, is reacted in a hydrocracking reactor to form shorter-chain hydrocarbons. In a separator arrangement, which in preferred embodiments can be multi-stage, unreacted wax is separated in a first hot separator. In preferred embodiments, this can be recycled back into the feed tank, thereby enabling complete elimination of the wax fraction. In a cold separator, the produced shorter-chain hydrocarbons are separated from the remaining gas stream and conveyed to an oil feed tank of the HTE.The remaining gas stream, comprising unreacted hydrogen and byproducts of the cracking reaction, mainly short-chain hydrocarbons such as methane and ethane, is fed into the exhaust gas of the HTE.

[0045] The oil phase discharged from the FT synthesis unit is also conveyed to an oil storage tank of the HTE and mixed there with the shorter-chain products of the hydrocracking reaction. The mixed oil phase is then separated into the desired fractions in a separation unit. In one embodiment of the present invention, this separation is carried out by distillation. By means of internal recirculation to the wax storage tank of the HTE, the long-chain fraction of the oil phase resulting from the upper boiling end of the product fractions can be fed to the hydrocracker and thereby also eliminated.

[0046] The light oil fraction resulting from the separation unit, which preferably consists of C5 to C10 hydrocarbons, can be extracted from the HTE as naphtha (brine gasoline) or further processed within the HTE, preferably by additional processing steps such as isomerization, to produce higher-octane naphtha. A target fraction separated by the separation unit can also be processed into standard-compliant fuel in an isomerization and hydrogenation unit. For this purpose, a high hydrogen input is necessary due to the nature of the reaction.

[0047] In some variants, the fuel can be separated from the gas phase in at least one downstream separator, and the remaining gas stream, comprising unreacted hydrogen and by-products of the isomerization and hydrogenation unit, can be fed to the exhaust gas of the HTE.

[0048] The exhaust gas of the entire HTE, comprising unreacted hydrogen from the hydrocracking unit and the isomerization and hydrogenation unit, and short-chain hydrocarbons from side reactions of the aforementioned processing units, is added to the synthesis gas production in the form of a gas recirculation of the RWGS within the scope of the present invention.

[0049] In preferred embodiments of the present invention, the processes within the HTE include temperatures between 50 and 350°C, preferably between 100 and 300°C, pressures up to 70 bar, particularly up to 50 bar, and are carried out with precious metal, in particular platinum and / or palladium, supported on aluminum oxide, or zeolites. It is known to those skilled in the art that a wide range of temperatures and pressures is possible in the processes themselves, depending on the desired products.

[0050] In preferred embodiments, the process conditions for isomerization are: catalyst = Pt / gamma-Al 2 O 3 , ratio H 2 / CH 2 = 2 , isomerization temperature 240°C , pressure = 20 bar.

[0051] The present invention relates in particular to a device for the production of standard-compliant fuels. A) an optional unit for providing a CO₂ / H₂ mixture; B) a Fischer-Tropsch synthesis unit comprising or consisting of: at least one RWGS stage configured for the conversion of CO₂ and H₂ to synthesis gas, wherein the synthesis gas comprises CO and H₂ or CO and H₂ and H₂O, and optionally CO₂ and CH₄; at least one Fischer-Tropsch stage configured for the conversion of synthesis gas comprising CO and H₂ in a Fischer-Tropsch synthesis; C) optionally at least one discharge device for product streams originating from the Fischer-Tropsch synthesis; C) a work-up unit configured for receiving and processing Fischer-Tropsch products discharged from the synthesis unit, in particular the wax phase and the oil phase, comprising or consisting of at least one of the following three subunits: i) isomerization unit; ii) cracking unit, preferably a hydrocracking unit; iii) hydrogenation unit, optional but preferably.at least one separation unit, at least one hydrogen feed line, one or more discharge lines, each configured for discharge from a fraction containing a standard-compliant fuel, optionally a discharge line for an aqueous phase, preferably a discharge line for an aqueous phase, and at least one discharge line for gases produced, comprising hydrogen and C1 to C4 hydrocarbons, , characterized in that the discharge for the accumulating gases is designed as a return line for the gases to the RWGS, and that the device does not have a purification device for the gases accumulating in the processing unit, which are returned to the synthesis unit RWGS.

[0052] Essential to the present invention is that the synthesis unit and the processing unit are located in relatively close proximity to each other, so that the return of the hydrogen-containing gases generated in the processing unit to the synthesis unit can be accomplished by means of equipment.

[0053] While a pipeline would in principle also be suitable for this gas recirculation, this would not negatively affect the hydrogen saving effect of the present invention, but would negate the advantages due to increased energy expenditure.

[0054] Therefore, within the scope of the present invention, it is preferred if the synthesis unit and the processing unit are located on the same site, preferably such that the return line is less than 10 m long. It is particularly preferred if the synthesis unit and the processing unit are located directly next to each other with a distance of less than 1 m, or even in the same housing.

[0055] The discharge device for product streams (C0) originating from Fischer-Tropsch synthesis can be configured or designed in various ways. It can be designed to discharge all product streams, or it can be designed to discharge only specific product streams. It is also possible to discharge a portion of each product stream while the remainder is routed to the processing unit. In this respect, the discharge device can be configured, for example, as a flow diverter or as multiple flow diverters. The proportion of each FT product routed to the processing unit depends on the target fuel. It is quite possible, for instance, that the oil phase alone already meets the requirements of a fuel standard.

[0056] The exact configuration of the synthesis unit and the processing unit must be selected by a person skilled in the art based on the desired products. Since the units are known to the person skilled in the art, this is readily possible. In particular, the exact sequence of the processing subunits and their interconnection can vary. It is only necessary that the synthesis unit, the processing unit, and the subunits are connected to each other in appropriate functional configurations.

[0057] In preferred embodiments, the device of the present invention is accordingly arranged on a site, preferably in an apparatus complex, in particular in a housing.

[0058] In preferred embodiments, the reprocessing unit comprises at least two, preferably at least three, in particular all four of the aforementioned subunits.

[0059] In the present invention, the device does not include a purification device for the gases generated in the processing unit, which are returned to the RWGS of the synthesis unit.

[0060] In preferred embodiments of the present invention, the processing unit C) for the processing of wax phase and oil phase comprises the following plant components, wherein the respective plant components are interconnected, or consists of the following: CA) Feed lines for a wax phase, an oil phase, hydrogen; CB) a hydrocracking reactor unit, which may consist of one or more subunits, configured to react wax phase with hydrogen; CC) one or more separator units, configured to separate the product from unit CB) into C-Ca) a long-chain, waxy fraction C-3a), C-Cc) a short-chain, oily fraction C-3c), and C-Cd) hydrogen or hydrogen-containing gases C-3d);CD) a mixing unit configured for mixing the oil phase with the short-chain, oily fraction C-3c), CE) one or more separation units configured for separating the mixture obtained in the mixing unit CD) into 5a) a long-chain, waxy fraction, 5c) a short-chain fraction which can be discharged as product, in particular naphtha, 5d) a medium-chain fraction, comprising Ea) a return line for fraction C-5a) to the wax phase, Ec) a discharge line for C-5c), Ed) a discharge line for fraction C-5d);CF) an isomerization and hydrogenation unit configured for the reaction of fraction C-5d) with the addition of hydrogen, CG) one or more separator units configured for the separation of the mixture obtained in unit CF) into C-Ga) fuel and C-Gb) hydrogen or hydrogen-containing gases, wherein the plant is configured to return the hydrogen-containing gases obtained in CC) and CG) to the Fischer-Tropsch synthesis unit B).

[0061] It should be noted that the relative designations given in this variant of the present invention, such as "shorter-chain," etc., are related to each other within this embodiment. This means that their relationship to other embodiments is not necessarily the same; for example, a shorter-chain fraction of this embodiment could be short-chain or long-chain in relation to another embodiment.

[0062] The present invention further relates to a method for producing standard-compliant fuels, comprising A) Provision of a CO 2 / H 2 mixture B) Introduction of the CO 2 / H 2 mixture into a Fischer-Tropsch synthesis unit, conversion of CO 2 and H 2 to CO and H 2 in an RWGS reaction, whereby H 2 O and CO 2 may be present as byproducts.Reaction of CO and H₂ in a Fischer-Tropsch synthesis, C₀) optionally derivation of one or more product streams from the Fischer-Tropsch synthesis, and C) collection and work-up of Fischer-Tropsch products derived from the Fischer-Tropsch synthesis that were not derived in C₀), in particular the wax phase and the oil phase, with the addition of hydrogen by at least one of the following three reactions: i) isomerization, ii) cracking, preferably hydrocracking, iii) hydrogenation, optionally, but preferably, separation, derivation of at least one fraction containing a standard fuel, optionally derivation of aqueous phase, preferably derivation of aqueous phase, and derivation of gases obtained in the work-up, comprising hydrogen and C₁ to C₄ hydrocarbons. characterized in that the discharge of the gases produced is carried out as a return to the RWGS, and that the gases produced in the processing unit are returned to the synthesis unit without purification.

[0063] In preferred embodiments, the processing of the wax and oil phase derived from the Fischer-Tropsch synthesis as Fischer-Tropsch products in step C) comprises or consists of the following steps: Ia) Provision of the wax phase, optionally in a feed vessel; II) Introduction of the wax phase together with hydrogen into a hydrocracking reactor and conversion to shorter-chain hydrocarbons; III) Separation of the product obtained in step II) into 3a) long-chain, waxy fraction, which is recycled to Ia); 3c) short-chain, oily fraction; 3d) hydrogen or hydrogen-containing gases; IV) Provision of an oil phase, optionally in a feed vessel, and mixing of the oil phase with the short-chain, oily fraction from 3c), optionally with simultaneous, at least partial, degassing; V) Separation of the mixture from IV) into 5a) long-chain, waxy fraction, which is recycled to Ia); 5c) short-chain fraction, which can be discharged as product, in particular naphtha; 5d) medium-chain fraction; VI) Conversion of fraction 5d) with the addition of hydrogen in an isomerization and hydrogenation unit,VII) Separation of the product from VI) into 7a) fuel, in particular kerosene, 7b) hydrogen or hydrogen-containing gases, wherein the hydrogen-containing gases obtained in steps III) and VII) are recycled.

[0064] It should be noted that the relative designations given in this variant of the present invention, such as "shorter-chain," etc., are related to each other within this embodiment. This means that their relationship to other embodiments is not necessarily the same; for example, a shorter-chain fraction of this embodiment could be short-chain or long-chain in relation to another embodiment.

[0065] In one variant, the present invention relates to a process for producing standard-compliant fuels from a wax phase, an oil phase, which in this embodiment are preferably FT products but can also originate from other sources, and hydrogen, comprising the following steps or consisting of these: Ia) Providing a wax phase, optionally in a holding vessel, whereby this corresponds to a direct conversion from the product stream of a PtL or introduction into a holding tank; II) Introducing the wax phase together with hydrogen into a hydrocracking reactor and converting it to shorter-chain hydrocarbons; III) Separating the product obtained in step II) into 3a) long-chain, waxy fraction, which is recycled to Ia); 3c) short-chain, oily fraction; 3d) hydrogen or hydrogen-containing gases; IV) Providing an oil phase, optionally in a holding vessel, whereby this corresponds to a direct conversion from the product stream of a PtL or introduction into an oil holding tank and mixing the oil phase with the short-chain, oily fraction from 3c), optionally with simultaneous, at least partial, degassing; V) Separating the mixture from IV) into 5a) long-chain, waxy fraction, which is recycled to Ia); 5c) short-chain fractionwhich can be extracted as a product, in particular naphtha, 5d) medium-chain fraction, VI) reaction of fraction 5d) with the addition of hydrogen in an isomerization and hydrogenation unit, VII) separation of the product from VI) into 7a) fuel, in particular kerosene, 7b) hydrogen or hydrogen-containing gases, , wherein the hydrogen-containing gases produced in steps III) and VII) are recycled and added to the reactant hydrogen stream.

[0066] It should be noted that the relative designations given in this variant of the present invention, such as "shorter-chain," etc., are related to each other within this embodiment. This means that their relationship to other embodiments is not necessarily the same; for example, a shorter-chain fraction of this embodiment could be short-chain or long-chain in relation to another embodiment.

[0067] In this embodiment of the present invention, step III) may comprise the separation of the product obtained in step II) in a hot separator into a long-chain, waxy fraction 3a), which is returned to Ia), and a shorter-chain, oilier fraction 3b), and optionally a further separation of the shorter-chain fraction in a cold separator into a short-chain, oily fraction, and hydrogen or hydrogen-containing gas, which is recovered.

[0068] In this embodiment of the present invention, step V) can also comprise the separation of the product obtained in step IV) in a first separation unit into a long-chain, waxy fraction 5a), which is recycled to Ia), and a shorter-chain, oilier fraction 5b), and optionally a further separation of the shorter-chain fraction in a second separation unit into a short-chain, oily product fraction 5c), in particular naphtha, and a medium-chain fraction 5d).

[0069] In this variant of the present invention, the separation in step VII) can also take place in a cold separator.

[0070] Furthermore, in this embodiment of the present invention, the hydrogen or hydrogen-containing gases produced in steps III) and VII) are recycled without further processing, in particular without purification, and added to the reactant hydrogen stream. This means that the recycled gas stream can also include short-chain hydrocarbons, in particular C1 to C4 hydrocarbons.

[0071] Similarly, in this variant of the present invention, the oil phase and the wax phase can be products of a Fischer-Tropsch synthesis.

[0072] In this variant of the present invention, the wax phase and the oil phase can also be derived from a power-to-liquid process, preferably from a power-to-liquid process based on a Fischer-Tropsch synthesis.

[0073] In one embodiment of the present invention, the processing unit C) for receiving and processing the products coming from the Fischer-Tropsch synthesis unit can comprise or consist of the following plant components, wherein the respective plant components are interconnected: CA) Feed lines for C-Aa) a wax phase, C-Ab) an oil phase, C-Ac) hydrogen; CB) a hydrocracking reactor unit, which may consist of one or more subunits, configured to react wax phase with hydrogen; CC) one or more separator units, configured to separate the product from unit CB) into C-Ca) a long-chain, waxy fraction C-3a), C-Cc) a short-chain, oily fraction C-3c), and C-Cd) hydrogen or hydrogen-containing gases C-3d);CD) a mixing unit configured for mixing the oil phase with the short-chain, oily fraction C-3c), CE) one or more separation units configured for separating the mixture obtained in the mixing unit CD) into C-5a) a long-chain, waxy fraction, C-5c) a short-chain fraction that can be discharged as product, in particular naphtha, C-5d) a medium-chain fraction, comprising C-Ea) a return line for fraction C-5a) to the wax phase, C-Ec) a discharge line for C-5c), C-Ed) a discharge line for fraction C-5d); CF) an isomerization and hydrogenation unit configured for reacting fraction C-5d) with the addition of hydrogen, CG) one or more separator units configured for separating fraction C-5d) into C-Ga) fuel and C-Gb) hydrogen or hydrogen-containing gases; the plant is configured to return the hydrogen-containing gases generated in CC) and CG) and add them to the feed hydrogen stream or directly to the RWGS without further processing.

[0074] It should be noted that the relative designations given in this embodiment of the present invention, such as "shorter-chain," etc., are related to each other within this embodiment. This means that their relationship to other embodiments is not necessarily the same; for example, a shorter-chain fraction of this embodiment could be short-chain or long-chain in relation to another embodiment.

[0075] Furthermore, it should be taken into account that the reprocessing unit of this embodiment can replace that of the one described above with sub-features C1), C2), C3) and C4).

[0076] In this embodiment of the present invention, CC) can comprise or consist of two separator units, wherein the first separator unit, preferably a hot separator unit, is configured to separate the product from unit CB) into a long-chain, waxy fraction C-3a) and a shorter-chain, oilier fraction C-3b), and wherein the second separator unit, preferably a cold separator unit, is configured to separate the shorter-chain fraction from the first separator unit into a short-chain, oily fraction C-3c), and hydrogen or hydrogen-containing gas C-3d). The separator units are configured such that the long-chain, waxy fraction from the first separator unit is recycled into the wax phase.

[0077] In this embodiment of the present invention, CE) can also comprise or consist of two separation units, wherein a first separation unit is configured to separate the mixture obtained in mixing unit CD) into a long-chain, waxy fraction C-5a) and a shorter-chain, oilier fraction C-5b), and a second separation unit is configured to further separate fraction C-5b) into a short-chain, oily product fraction C-5c), in particular naphtha, and a medium-chain fraction C-5d). The separation units are configured such that the long-chain, waxy fraction from the first separation unit is recycled back into the wax phase.

[0078] In this and all other variations of the processing units according to the invention, CG) can be configured as a separator, preferably a cold separator.

[0079] Within the scope of the present invention, the processing units are configured such that the hydrogen or hydrogen-containing gases generated in CC) and CG) are recycled without further processing, in particular without purification, and added either to the feed hydrogen stream or to an RWGS plant without further processing.

[0080] In embodiments of the present invention, a hydrogen supply line can be arranged in the Fischer-Tropsch synthesis unit between the RWGS stage and the Fischer-Tropsch stage.

[0081] In embodiments of the present invention, a hydrogen supply can be provided in the process according to the invention between the conversion of CO 2 and H 2 to CO and H 2, which takes place in an RWGS reaction, and the conversion of CO and H 2 in a Fischer-Tropsch synthesis.

[0082] In particular, the processing unit according to the invention is coupled to a power-to-liquid plant, especially to a power-to-liquid plant based on a Fischer-Tropsch synthesis, in such a way that the wax phase and the oil phase originate from the products of the power-to-liquid plant.

[0083] An advantage of the present invention is that no purification of the gas is required in order to feed the gas mixture into the RWGS of synthesis gas production.

[0084] One advantage of the present invention is that the hydrogen requirement required for a PtL plant and the total hydrogen requirement required for both process steps, i.e., the PtL process and refining, are reduced.

[0085] It was surprisingly found that the recycling of hydrogen-containing gases from the hydrotreatment into the RWGS is possible without further processing, even though the high hydrogen content in these gases results in a high H2 / CO ratio.

[0086] A particular advantage of the present invention is that, by specifically adjusting the parameters in the individual process steps or in the individual device parts, it is possible to produce fuels that comply with standards.

[0087] The expert knows exactly how to set the parameters in each case based on their general expertise, and this is done using the desired target products as a guide.

[0088] It is particularly advantageous that, within the scope of the present invention, one is not bound by existing standards, for example, but not exclusively those mentioned above, but can react flexibly to changing standards and adapt the process and device parameters in order to also meet the changed standards and their requirements.

[0089] Where, in the description of the system according to the invention, parts or the entire system are characterized as "consisting of," this is to be understood as referring to the aforementioned essential components. Obvious or inherent parts such as pipes, valves, screws, housings, measuring devices, storage containers for reactants / products, etc., are not thereby excluded. Preferably, however, other essential components, such as additional reactors or similar items that would alter the process flow, are excluded.

[0090] The various embodiments of the present invention, e.g. - but not exclusively - those of the various dependent claims, can be combined with each other in any way, provided that such combinations do not contradict each other. Examples:

[0091] The invention will now be further explained with reference to the following non-limiting examples. Example 1:

[0092] When the production of liquid (FT oil) and solid hydrocarbons (FT wax) at room temperature is spatially separated, a demand for hydrogen arises both at the PtL site and in the downstream processing site (e.g. a refinery).

[0093] As an example, the requirement was normalized to an input flow of one ton of CO2 per hour.

[0094] The synthesis unit at the PtL site then requires an hourly hydrogen feed of 127 kg to produce the FT products. The refining process then requires a further 36.6 kg per hour, totaling 163.6 kg of hydrogen per hour.

[0095] With spatial separation of the PtL site and refinery as in the state of the art, these quantities of hydrogen are always required because hydrogen generated during processing on the refinery side is extracted and disposed of, at a rate of 27.3 kg per hour.

[0096] In contrast, the present invention does not involve spatial separation, and the hydrogen produced during the work-up process is recycled back into the synthesis unit. Therefore, the aforementioned 27.3 kg per hour from the work-up unit are not lost in the present invention, meaning that the continuous feed of fresh (new) hydrogen into the synthesis unit only needs to be 99.7 kg per hour.

[0097] With the same production output of the PtL plant, the present invention enables the integration of the processing steps at the PtL site, thereby reducing the overall demand for hydrogen and enabling direct production of standard-compliant fuels at the PtL site.

[0098] The H2 management underlying this invention can thus reduce the hydrogen demand required for the PtL plant and the overall hydrogen demand required for both process steps.

[0099] A comparison of these data shows that, of a total hydrogen requirement of 163.6 kg / h of hydrogen (127 + 36.6) per 1000 kg / h of CO₂, 27.3 kg / h must be extracted and disposed of unused in the prior art. This hydrogen is recycled and reused in the present invention. Therefore, the present invention achieves a hydrogen saving of approximately 17%. Example 2:

[0100] A method according to the invention was carried out, using the following characteristics: Temperature during RWGS: 740°C; Temperature during FT synthesis: 240°C; Temperature during separation: 190°C; Pressure: 20 bar; Proportion of recycled gases (in steady-state operation): 18 vol.%

[0101] Accordingly, a CO 2 / H 2 mixture was provided and introduced into a Fischer-Tropsch synthesis unit, in which first a conversion of CO 2 and H 2 to CO and H 2 took place in an RWGS reaction and subsequently a conversion of CO and H2 in a Fischer-Tropsch synthesis.

[0102] The gases, comprising C1 to C4 hydrocarbons, obtained after the processing of the products obtained from Fischer-Tropsch synthesis were returned directly to the RWGS as a recycling stream without purification (the exact method of processing the FT products is not specified, as it is not relevant for this example; in this example, only the gases obtained are important).

[0103] The hydrogen supply was controlled during operation depending on the proportion of recycled gas; that is, as the amount of recycled gas increased, correspondingly less hydrogen was added. The corresponding amounts are in Figure 4 shown, where the hydrogen supply is represented by a dashed line and the recycling stream by a dash-dot line (see also the legend of the Figure 4 ).

[0104] Since the recycled gas contains a proportion of C1 to C4 hydrocarbons, the carbon dioxide input was also adjusted accordingly, depending on the amount of recycled gas. The amount of carbon dioxide input is determined in Figure 4 represented by a dotted line.

[0105] The ratio of H₂ to CO was determined by gas chromatographic measurements of the RWGS product stream. The measured values ​​for the H₂ to CO ratio are shown in Figure 4 represented as points.

[0106] The result of this example was that an increasing proportion of recycled gas does not significantly change the H2 / CO ratio. Character description:

[0107] The present invention is explained in more detail below with reference to the drawings. The drawings are not to be interpreted as limiting and are not to scale. Furthermore, the drawings do not include all the features found in conventional systems, but are reduced to those essential for the present invention and its understanding.

[0108] Figure 1Figure 1 schematically illustrates the present invention. CO₂ and H₂ as feed gas A are converted into Fischer-Tropsch products in a synthesis unit 1. In the example shown, the synthesis unit 1 schematically consists of a RWGS 2 and the actual Fischer-Tropsch system 3. In the RWGS 2, CO₂ and H₂ are converted to synthesis gas, i.e., to CO and H₂, whereby the byproducts CO₂ and H₂O may also be present in the product gas.CO and H₂ are then reacted in the FT unit 3 to form a product mixture B consisting of a gas phase comprising unreacted synthesis gas (mainly CO, H₂), short-chain hydrocarbons, and volatile components of the byproducts, as well as CO₂; a waxy phase of long-chain hydrocarbons that is solid at ambient temperature and pressure (wax phase); a hydrophobic phase of shorter-chain hydrocarbons that is liquid at ambient temperature and pressure (oil phase); and an aqueous phase consisting of the water of reaction formed and dissolved organic compounds. This product mixture B (FT product) is then fed into the work-up unit 4. As indicated in the figure, it is possible to divert a portion of the FT product B. This diverted portion C can comprise whole or partial components of the four phases mentioned.For example, it is possible to divert part or all of the oil phase, provided this phase is intended for a specific use, and feed the remainder into processing unit 4. In processing unit 4, the FT product B can then be processed by isomerization, cracking, hydrogenation, and separation. For this purpose, hydrogen F is supplied to processing unit 4. At least one standard-compliant liquid fuel D is then discharged from processing unit 4. The hydrogen-containing gas stream E generated in processing unit 4, which may still contain C1 to C4 hydrocarbons, is recycled back into synthesis unit 1, specifically RWGS unit 2, without further purification. Recycling the hydrogen-containing stream E requires significantly less hydrogen than a prior art process.

[0109] Figure 2aThis shows the previous state of the art. In contrast to the present invention, the PtL site and the refinery are geographically separated (symbolized by two dashed boxes, the upper one representing the PtL site and the lower one the refinery). The upper box shows the PtL site, to which a synthesis unit 1 is connected. Figure 1 is located, and in the upper box is the refinery, where a processing unit 4 is located accordingly Figure 1 The synthesis unit is located there. Hydrogen A1 and carbon dioxide A2 are introduced into the synthesis unit, yielding (among other products) oil phase B1 and wax phase B2. These two phases B1 and B2 are processed in the processing unit 4, resulting in product D. According to the state of the art, as this Figure 2aAs illustrated, due to the spatial separation of the PtL site and the refinery, there is no equipmental connection between synthesis unit 1 and processing unit 4. Consequently, all the hydrogen A1 required for synthesis unit 1 must be supplied on-site at the PtL site, and the hydrogen A1-II required for processing must also be supplied entirely at the refinery. Furthermore, the hydrogen produced during processing must be discharged via a duct G at the refinery and disposed of (e.g., by incineration).

[0110] Figure 2b shows essentially the same structure as Figure 2aHowever, in the configuration according to the present invention, the fundamental reactions taking place in the units are essentially the same, as are the gas flows supplied to and discharged from the respective units. The difference from the prior art is that the PtL site includes not only the synthesis unit 1 but also the processing unit 4, which is not located elsewhere, namely in the refinery (symbolized by a large dashed box encompassing both units). This makes it possible to directly feed the hydrogen produced in processing unit 4 back into the synthesis unit as recycled stream E. This has two enormous advantages: firstly, it reduces the required amount of hydrogen, and secondly, the hydrogen produced during processing does not need to be disposed of. Thus, enormous ecological, economic, and technical advantages are achieved.

[0111] A comparison of Figures 2a and 2bThis shows that, of a total hydrogen requirement of 163.6 kg / h of hydrogen (127 + 36.6) per 1000 kg / h of CO₂, 27.3 kg / h must be extracted and disposed of unused in the prior art, whereas this amount is recovered and reused in the present invention. Therefore, the present invention achieves a hydrogen saving of approximately 17%.

[0112] Figure 3 shows one possible method for processing FT products.

[0113] In this example, both the wax phase B2 and the oil phase B1 are temporarily stored in storage tanks ST2 / ST1. The oil phase B1 can be degassed in storage tank ST1 at any time if necessary (not shown). The wax phase B2, or a certain portion thereof, is then fed into a hydrocracking reactor HC and reacted there with the addition of hydrogen from hydrogen supply A1-II. The product then enters a hot separator HT, where it is separated. One phase is returned to storage tank ST2, and the other is fed into a cold separator CT1. In the cold separator CT1, it is separated into a gas stream containing hydrogen, which is recycled as the recycling stream E, and a fraction that is fed into the aforementioned storage tank ST1 containing the oil phase B1. From this storage tank ST1, the mixture is fed into a separation unit S1.The bottom product obtained there is returned to the storage tank ST2 for the wax phase, and the overhead product is fed into another separation unit S2. In this example, the overhead product from this unit is discharged as naphtha, i.e., as product D1. The bottom product from the second separation unit S2 is then fed into an isomerization reactor I, where it reacts with the addition of hydrogen from the hydrogen supply A1-II. The resulting product is fed into a cold separator CT2, where it is separated into hydrogen-containing gas – which is recycled as stream E – and fuel, which is discharged as product D2.

[0114] It should be taken into account that the in Figure 3 The arrangement of the plant components shown is merely one possibility, but not the only one.

[0115] Figure 4 shows a graphical representation of the material flows according to Example 2. Reference symbol list:

[0116] 1 Synthesis unit 2 RWGS unit 3 FT plant 4 Reprocessing unit A Gas supply containing hydrogen and carbon dioxide gas A1 Hydrogen supply A2 Carbon dioxide supply A1-II Hydrogen supply for reprocessing B FT product B1 Oil phase B2 Wax phase C Finished FT product (directly from 1) D Product (standard fuel) D1 Naphtha D2 Jet fuel (fuel) E Recycling stream containing hydrogen and C1 to C4 hydrocarbons G Hydrogen discharge II Semimerization unit S1 Separation unit 1 S2 Separation unit 2 CT1 Cold separator 1 CT2 Cold separator 2 HC Hydrocracking reactor HT Hot separator ST1 Storage tank 1 ST2 Storage tank 2

Claims

1. Device for the production of standard-compliant fuels comprising A) an optional unit for providing a CO2 / H2 mixture B) a Fischer-Tropsch synthesis unit comprising or consisting of: - at least one RWGS stage configured for the conversion of CO2 and H2 to synthesis gas, - at least one Fischer-Tropsch stage configured for the conversion of CO and H2 in a Fischer-Tropsch synthesis, C0) optionally at least one discharge device for product streams originating from the Fischer-Tropsch synthesis, C) processing unit configured for receiving and processing Fischer-Tropsch products discharged from the synthesis unit, in particular the wax phase and the oil phase, comprising or consisting of - at least one of the three subunits: i) isomerisation unit, ii) cracking unit, preferably hydrocracking unit, iii) hydrogenation unit, - optionally at least one separation unit, - at least one feed line for hydrogen, - one or more discharge lines, each configured for the discharge of a fraction containing a standard-compliant fuel in each case, - optionally one discharge line for an aqueous phase, and - at least one discharge line for formed gases comprising hydrogen and C1- to C4-hydrocarbons, characterised in that the at least one discharge line for the formed gases is designed as a recycle line for the gases into the RWGS, and in that the device does not have a purification device for the gases formed in the processing unit which are recycled to the RWGS.

2. Device according to claim 1, characterized in that it is arranged in one plant complex, in particular in one housing.

3. Device according to any one of the preceding claims, characterized in that the processing unit comprises at least two, preferably all three sub-units i), ii) and iii).

4. Device according to any one of the preceding claims, configured to produce at least one of the fuels kerosene, diesel or petrol as a product.

5. Device according to any one of the preceding claims, characterized in that the processing unit C) for the processing of wax phase and oil phase, comprises or consists of the following plant parts, wherein the respective plant parts are in operative connection with each other: C-A) feed lines for C-Aa) a wax phase, C-Ab) an oil phase, C-Ac) hydrogen; C-B) a hydrocracking reactor unit, which may consist of one or more sub-units, configured for the conversion of wax phase with hydrogen; C-C) one or more separation units configured for the separation of from the product of unit C-B) into C-Ca) a long chain waxy fraction C-3a), C-Cc) a short-chain oily fraction C-3c), and C-Cd) hydrogen or hydrogen-containing gases C-3d); C-D) a mixing unit configured for the mixing of oil phase with the short-chain oily fraction C-3c), C-E) one or more separation units configured for the separation of the mixture obtained in the mixing unit C-D) into 5a) a long-chain, waxy fraction, 5c) a short-chain, fraction which can be discharged as a product, in particular naphtha, 5d) a medium-chain fraction, comprising Ea) a return line for the fraction C-5a) to the wax phase, Ec) a discharge line for C-5c) Ed) a discharge line for fraction C-5d); C-F) an isomerisation and hydrogenation unit configured for the conversion of fraction C-5d) with the addition of hydrogen, C-G) one or more separation units configured for the separation of the mixture obtained in unit C-F) into C-Ga) fuel and C-Gb) hydrogen or hydrogen-containing gases, wherein the device is configured to recycle the hydrogen-containing gases formed in C-C) and C-G) into the RWGS of the Fischer-Tropsch synthesis unit B).

6. Device according to any one of the preceding claims, characterized in that a hydrogen feed line is arranged in the Fischer-Tropsch synthesis unit B) between the RWGS stage and the Fischer-Tropsch stage.

7. Process for the production of standard-compliant fuels, comprising A) providing a CO2 / H2 mixture B) feeding the CO2 / H2 mixture into a Fischer-Tropsch synthesis unit, - conversion of CO2 and H2 to CO and H2 in a RWGS reaction, - conversion of CO and H2 in a Fischer-Tropsch synthesis, C0) optionally discharging one or more product streams from the Fischer-Tropsch synthesis, and C) receiving and processing Fischer-Tropsch products discharged from the Fischer-Tropsch synthesis which were not discharged in C0), in particular the wax phase and the oil phase, - with the addition of hydrogen by - at least one of the following three conversions: i) isomerisation, ii) cracking, preferably hydrocracking, iii) hydrogenation, - optionally separation, - discharging of at least one fraction containing a standard-compliant fuel, - optionally discharging of aqueous phase, and - discharging of gases formed in the processing, comprising hydrogen and C1- to C4-hydrocarbons, characterised in that the discharging of the formed gases is carried out as recycle into the RWGS, and in that the gases formed in the processing unit are recycled to the RWGS without purification.

8. Process according to claim 7, characterized in that the processing of the wax and oil phase discharged from the Fischer-Tropsch synthesis as Fischer-Tropsch products in step C) comprises or consists of the following steps: Ia) providing the wax phase, optionally in a feed vessel, II) introducing the wax phase together with hydrogen into a hydrocracking reactor and converting to shorter chain hydrocarbons III) separating the product obtained in step II) into 3a) long-chain waxy fraction, which is recycled to Ia), 3c) short-chain oily fraction, 3d) hydrogen or hydrogen-containing gases, IV) providing an oil phase, optionally in a feed vessel, and mixing the oil phase with the short-chain oily fraction from 3c), optionally with simultaneous, at least partial, degassing, V) separating the mixture from IV) into 5a) long-chain, waxy fraction, which is recycled to Ia), 5c) short-chain, fraction which can be discharged as a product, in particular naphtha, 5d) medium chain fraction, VI) conversion of fraction 5d) with the addition of hydrogen in an isomerisation and hydrogenation unit, VII) separation of the product from VI) into 7a) fuel, in particular kerosene, 7b) hydrogen or hydrogen-containing gases, wherein the hydrogen-containing gases formed in steps III) and VII) are recycled.

9. Process according to any one of claims 7 or 8, characterized in that all process steps are carried out in one plant complex, in particular in one housing.

10. Process according to any one of claims 7 to 9, characterized in that step C) comprises at least two, preferably all three conversions i), ii) and iii).

11. Process according to any one of claims 7 to 10, wherein the steps are carried out such that at least one of the fuels kerosene, diesel or petrol is obtained as a product.

12. Process according to any one of claims 7 to 11, characterized in that in step B) a hydrogen feed is performed between the conversion of CO2 and H2 to CO and H2, in a RWGS reaction, and the conversion of CO and H2 in a Fischer-Tropsch synthesis.

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