A process for producing sustainable aviation fuel

Abstract

A process for producing a sustainable aviation fuel component is described, wherein the process comprises two integrated sub-processes A and B. The sub-processes A comprises providing a renewable feedstock comprising triglycerides, hydrolyzing the triglycerides into free fatty acids which are subjected to a hydrocracking to produce a first hydrocarbon intermediate A. In the sub-processes B of the integrated process, any light hydrocarbons, oxygenates and glycerol released in the sub-processes A are refined into further hydrocarbons, hydrocarbon intermediate B, which together with hydrocarbon intermediate A are isomerized and a sustainable aviation fuel or sustainable aviation fuel component is provided.

Description

[0001] A PROCESS FOR PRODUCING SUSTAINABLE AVIATION FUEL

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to fuel production. The invention relates particularly, though not exclusively, to production of sustainable aviation fuel and components thereof from a renewable feedstock, wherein sub-processes are integrated together to maximize energy, as well as carbon and hydrogen efficiency of the overall process and to provide a sustainable aviation fuel component with beneficial properties.

[0004] BACKGROUND

[0005] This section illustrates useful background information without admission of any technique described herein representative of the state of the art.

[0006] Presently, there is an ongoing need to reduce greenhouse gas emissions and / or carbon footprint in transportation, especially in aviation. Accordingly, the interest towards sustainable aviation fuels and aviation fuel components is and has been growing. Moreover, there is also an increasing interest to obtain renewable light hydrocarbons as a base stock for the chemical industry.

[0007] Processes for producing aviation fuel components from renewable raw materials have been proposed. However, the carbon efficiency of aviation fuel components has been relatively low in said processes. Moreover, processes where oxygen containing raw materials are hydrodeoxygenated suffer from significant hydrogen consumption and costs thereof. Therefore, there is an ongoing need to improve the carbon and hydrogen efficiency of sustainable aviation fuel (SAF) components in the processes producing sustainable aviation fuel or components thereto that could be used in aviation fuels. There is also an ongoing need to improve the energy efficiency of the processes producing sustainable aviation fuel components.

[0008] Many of the renewable feedstocks of biological origin comprise C18+ fatty acids, which restricts their efficient use in sustainable aviation fuel production, due to the properties of formed n- paraffins and i-paraffins affecting, for example, the boiling point range, cold flow properties, density, and cold viscosity of the final aviation fuel component.

[0009] Therefore, there is an ongoing need to utilize renewable feedstocks comprising C18+ fatty acids in sustainable aviation fuel production without unnecessary yield losses in the obtained products or by-products from the process.

[0010] The availability of renewable feedstocks providing hydrocarbons with carbon numbers readily suitable for fuel applications are limited, whereas light hydrocarbons are produced and released excessively. Renewable fuel production involving synthesis from low carbon number components has been studied, but still fails to provide satisfying solutions.

[0011] There is a need to develop current processes and production facilities to improve overall energy and carbon efficiency and hydrocarbon yields starting from renewable feedstock comprising triglycerides.

[0012] SUMMARY

[0013] In view of the above, an object of the invention is to provide a process for producing a sustainable aviation fuel (SAF) component as a main product from a renewable feedstock. An aim is to increase carbon efficiency of the sustainable aviation fuel component production process. Thus, an aim is to improve utilization of all the carbon present in the feed, more specifically any gases in addition to the carboxylic acids and / or any esters thereof in the renewable feedstock with a carbon number C18 or longer, for production of the SAF component. Moreover, this aim can also be obtained by utilizing any additional products from the process. An aim is also to increase hydrogen efficiency of the sustainable aviation fuel component production process. An aim is to minimize hydrogen consumption in the process for producing a sustainable aviation fuel component. A further aim is to use the feedstock as efficiently as possible through process integration. Consequently, yet another aim is to minimize losses of any carbon present in the feed, and instead, direct any side streams to different unit operations within the overall process to eventually refine them to intermediates suitable to be converted to the aviation fuel component. Hence, the overall yield is further increased. Another aim is to decrease the need for impurity control. Another aim is to produce a SAF component having a hydrocarbon distribution which is especially beneficial for cold viscosity of the SAF component. In practice this means refining glycerol, oxygenates such as water (preferably in gas phase), light hydrocarbons optionally any heavy hydrocarbon fractions through a series of reactions in further reactors. The series of reactions in further reactors can be integrated through said streams of glycerol, oxygenates, light hydrocarbons, and optional heavy hydrocarbon fractions. Moreover, further refined hydrocarbon fractions from renewable sources may be recovered in addition to the sustainable aviation fuel component. Another aim is to make the best use of the renewable feedstock components when converting it into the SAF component.

[0014] According to a first example aspect there is provided a process for producing fuel components for sustainable aviation fuel (SAF) from a renewable feedstock comprising triglycerides, wherein the process comprises:

[0015] - a sub-process A for converting the renewable feedstock to a hydrocarbon intermediate A, comprising: h) subjecting the renewable feedstock to hydrolysis in the presence of water to produce glycerol, water and fatty acids, thereby obtaining an oil phase and an aqueous phase; he) subjecting the oil phase comprising fatty acids obtained in the hydrolysis at the step h) to hydrocracking, to obtain the hydrocarbon intermediate A suitable for isomerization, and hydrocracking by-products, such as light hydrocarbons and oxygenates;

[0016] - a sub-process B for converting products obtained from the sub-process A to a hydrocarbon intermediate B, comprising: r) reforming the glycerol obtained from the aqueous phase from the step h) and light hydrocarbons and oxygenates obtained from the step he), into a gas mixture comprising carbon oxide(s) and hydrogen; c) subjecting the gas mixture comprising carbon oxide(s) and hydrogen from step r) to carbon refining, to obtain a gas mixture comprising carbon monoxide and hydrogen gas; and s) subjecting the gas mixture comprising the carbon monoxide and hydrogen gas to hydrocarbon synthesis step selected from a Fischer-T ropsch process, isosynthesis process or methanol synthesis and upgrading process, and recovering the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from the hydrocarbon synthesis effluent; and

[0017] - step i) comprising isomerizing the hydrocarbon intermediate A from step he) and the hydrocarbon intermediate B from step s), to obtain at least a SAF component comprising C9 - C17 hydrocarbons.

[0018] In the above process disclosure, the steps are denoted by letters referring to the process initials instead of referring to the alphabetical order of letters. Considering each step individually is chosen to distance the sequence of steps from strict numerical order wherein one step would follow another but rather to emphasize the coexisting nature of sub-processes A and B and intermittent streams one and other ways therebetween. To help to comprehend the subprocesses and streams the steps are named in table 1 .

[0019] Table 1. The steps constituting the sub-processes A and B, which together with the shared isomerization step form the overall process of the present disclosure.

[0020] Surprisingly, the inventors have found that the process according to the first example aspect has a beneficial impact on the obtained SAF component properties, compared to prior art processes proceeding through hydrodeoxygenation of said renewable feedstock comprising triglycerides. The disclosed process also provides a SAF component with improved properties compared to prior art processes comprising hydrocracking reactions, or hydrocarbon synthesis selected from a Fischer-Tropsch process, an isosynthesis process, and a methanol synthesis and upgrading process alone (i.e., not integrated). The present process influences the SAF component properties at a plurality of process stages or steps.

[0021] More specifically, the SAF component properties are improved, as the SAF component obtained from the current process comprises cycloparaffins, which contribute to fuel properties such as improved cold viscosity of the obtained SAF component. In use as jet fuel, a SAF component low in aromatics benefits from cycloparaffins such as naphthenes acting similarly to aromatics on hot surfaces of the aviation engine and fuel system in general. Moreover, the SAF component properties are improved, as the SAF component obtained from the current process comprises broad carbon number distribution, contributing, for example, to good thermal properties of the SAF component. The broad distribution of carbon numbers further contributes to blending properties of the SAF component with possible other jet fuel components to provide the final SAF product. Without being bound to any theory, the breadth of the hydrocarbon distribution between carbon numbers C8 - C17 is believed to contribute to good blending. In other words, a composition containing several hydrocarbons of different chain lengths and substituents provides a better blend partner over e.g. an essentially pure compound, for example technical grade n-dodecane.

[0022] The SAF component has a broad distribution of the carbon numbers and carbon chain characteristics which contribute to good thermal properties, to a lower deposits formed (as combustion of all hydrocarbons of the product at aviation engine temperatures is efficient) in the aviation turbine engine fuel system on heating the fuel, and improved heat absorption and more effective heat transfer in the fuel system. Minimizing deposit formation during use is beneficial due to reduced maintenance needs, thus leading to prolonged service intervals.

[0023] Further, hydrogen consumption during the production process is decreased compared to processes refining renewable feedstocks comprising triglycerides through hydrodeoxygenation reaction.

[0024] Additionally, the process provides feasible routes for recycling compounds having carbon number from C1 to C4, which otherwise would not be efficiently used as commercial products without further processing.

[0025] In the schematic examples of the present disclosure, it is presented how the process for producing the SAF component is executed with enhanced carbon, hydrogen and energy efficiency, and minimal loss of energy as well as C1 to C4 compounds.

[0026] Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well.

[0027] BRIEF DESCRIPTION OF THE FIGURES

[0028] Some example embodiments will be described with reference to the accompanying figures, in which:

[0029] Fig. 1 schematically shows an embodiment of the current process for producing fuel components for SAF.

[0030] DETAILED DESCRIPTION

[0031] All standards and guidelines referred to herein are the latest revisions available at the filing date, unless otherwise mentioned.

[0032] By sustainable aviation fuel (SAF) is herein meant renewable aviation fuel which is produced sustainably and is able to reduce GHG emissions, preferably at least 70 percent, such as about 80 percent, compared to fossil jet fuel baseline, and helps the aviation industry to meet the ambitious CO2 reduction targets for the future. The SAF composition of the present disclosure contributes to reducing the GHG emissions at least 50 percent, such as at least 70 percent, or even such as at least 90 percent, by gCO2eq / MJ calculated according to the EU Renewable Energy Directive 2009 / 28 / EC. As used in the context of this disclosure, the properties of the sustainable aviation fuel component comply with the required product properties as set out in the ASTM D7566-22 Annex A2. It is understood that the chemical composition is dependent on the composition of the renewable feedstock comprising triglycerides. In an embodiment, the sustainable aviation fuel component obtained from the present process comprises mainly C9-C16 isoparaffins and napthenes (cycloalkanes), with minor amounts of C8 and C17 isoparaffins, aromatic compounds and some further C9 - C17 n-paraffins present. Preferably the sustainable aviation fuel or sustainable aviation fuel component obtained in the present process is of renewable origin.

[0033] Unless otherwise stated, regarding distillation characteristics and boiling ranges, reference is made to EN ISO 3405:2019. For boiling point distribution, reference may also be made to gas chromatography -based methods like ASTM D2887-19e1 . Fatty acid distribution for the feed may be determined according to ISO 12966-4:2015 or measured using known analysis methods based on e.g. GC-FID or GC-AED.

[0034] As used herein, with the term ’’feed” or “feedstock” is meant any feedstock which is fed into a particular reaction. The renewable feedstock comprising triglycerides is the starting material of the overall process and regarded as the primary origin for any streams containing carbon, for example when carbon efficiency is of interest. In view of the carbon efficiency, the present process is remarkable in a sense that through the present multistep process, even the carbon cleaved in the hydrocracking reactions as light hydrocarbons or oxygenates are refined into the desired end product components through reforming, carbon refining, hydrocarbon synthesis and isomerization steps (steps r), c), s) and i) respectively).

[0035] The renewable feedstock comprising triglycerides is renewable by origin, comprises triglycerides and is more specifically defined and exemplified in e.g. Fl 130345, FI20216369 or EP1741768. As used herein, the term ’’renewable” refers to compounds or compositions that are obtainable, derivable, or originating from plants and / or animals, including compounds or compositions obtainable, derivable, or originating from fungi and / or algae, in full or in part. As used herein, renewable compounds or compositions may comprise gene manipulated compounds or compositions. Renewable feeds, components, compounds or compositions may also be referred to as biological compounds or compositions, or as biogenic compounds or compositions.

[0036] As used herein, the term “fossil or mineral” refers to compounds or compositions that are obtainable, derivable, or originating from naturally occurring non-renewable compositions, such as crude oil, petroleum oil / gas, shale oil / gas, natural gas, or coal deposits, and the like, and combinations thereof, including any hydrocarbon-rich deposits that can be utilized from ground / underground sources. The term circular refers to recycled material typically originating from non-renewable sources, but which may also be of biogenic origin. For example, the term circular may refer to recycled material originating from waste plastics. Said renewable, circular, and fossil compositions are considered differing from one another based on their origin and impact on environmental issues. Therefore, they may be treated differently under legislation and regulatory framework. Typically, renewable, circular, and fossil compositions are differentiated based on their origin and information thereof provided by the producer.

[0037] Chemically the renewable or fossil origin of any organic compounds, including hydrocarbons, can be determined by a suitable method for analyzing the content of carbon from renewable sources e.g. DIN 51637 (2014), ASTM D6866 (2020), or EN 16640 (2017). Said methods are based on the fact that carbon atoms of renewable or biological origin comprise a higher number of unstable radiocarbon (14C) atoms compared to carbon atoms of fossil origin. Therefore, it is possible to distinguish between carbon compounds derived from renewable or biological sources or raw material and carbon compounds derived from non-renewable or fossil sources or raw material by analyzing the ratio of12C and14C isotopes. Thus, a particular ratio of said isotopes can be used as a “tag” to identify a renewable carbon compound and differentiate it from non-renewable carbon compounds. The isotope ratio does not change in the course of chemical reactions. Therefore, the isotope ratio can be used for identifying renewable compounds and compositions and distinguishing them from non-renewable, fossil materials in reactor feeds, reactor effluents, separated product fractions and various mixtures thereof.

[0038] Numerically, the biogenic carbon content can be expressed as the amount of biogenic carbon in the material as a weight percent of the total carbon (TC) in the material (in accordance with ASTM D6866 (2020) or EN 16640 (2017)). In the present context, the term renewable refers to a material having a high biogenic carbon content, typically more than 80 wt-%, preferably more than 85 wt- %, more preferably more than 90 wt-% or more than 95 wt-%, even more preferably about 100 wt-%, based on the total weight of carbon in the material (EN 16640 (2017)).

[0039] As used herein, “integrated process” refers to at least two processes, or sub-processes, which are integrated to each other through at least one process step. At least two processes can be further integrated through exchange of process stream(s) between said processes.

[0040] As used herein, a renewable feedstock comprising triglycerides is the starting material for the overall process.

[0041] With the term “carbon efficiency” is meant efficiency of the utilization of carbons present in the initial renewable feedstock, in the final products obtained from the overall process.

[0042] As used herein, the term ’’hydrotreatment (HT)” or “hydroprocessing”, means a catalytic process for treating organic material by means of molecular hydrogen. In the context of the present disclosure, hydrotreatment can comprise at least one or more of removal of oxygen from organic oxygen compounds as water i.e. hydrodeoxygenation (HDO), removal of sulfur from organic sulfur compounds as dihydrogen sulfide (H2S), i.e. hydrodesulfurization, (HDS), removal of nitrogen from organic nitrogen compounds as ammonia (NH3), i.e. hydrodenitrogenation (HDN), removal of halogens, for example chlorine from organic chloride compounds as hydrochloric acid (HCI), i.e. hydrodechlorination (HDCI), removal of metals by demetallization, removal of phosphorus through dephosphorization, hydroisomerization (HI) of the feed, hydrodearomatisation (HA) to saturate aromatic structures to cycloparaffins, and / or hydrogenation of olefinic bonds, if present in the feed.

[0043] As used herein, the term ’’hydroisomerization” refers to isomerization process in the presence of hydrogen, wherein the properties of the feedstock are improved by transforming normal / linear hydrocarbons to branched ones having essentially the same carbon number.

[0044] As used herein, the term ’’hydrocracking” refers to catalytic decomposition of organic hydrocarbon materials using molecular hydrogen at high pressure. In hydrocracking, the feedstock is catalytically converted to lower molecular weight compounds than in the compounds of the initial feedstock. The cracking conversion to lower molecular weight compounds is relatively unselective, and therefore carbon chains with various chain lengths are obtained through hydrocracking reactions.

[0045] As used herein, the term “oxygenate” refers to an oxygen containing compounds.

[0046] As used herein, “hydrocarbon synthesis” refers to Fischer-Tropsch process, isosynthesis process or methanol synthesis and upgrading.

[0047] As used herein, the “Fischer-Tropsch process” refers to catalytic FT-reaction from synthesis gas to a product mainly consisting of hydrocarbons, and necessary separations and possible further upgrading thereof to yield a hydrocarbon intermediate B. As such, the catalytic Fischer-Tropsch synthesis is well known in the art (see e.g. https: / / en.wikipedia.org / wiki / Fischer%E2%80%93Tropsch_process) and discussed in detail in e.g. Arno de Klerk, Fischer-Tropsch Refining, 2 / 2008, University of Pretoria, South-Africa, and further in view of upgrading in e.g. FI20236222, the contents of which are herein incorporated by reference.

[0048] As used herein, the term “isosynthesis process” refers to isosynthesis reaction and any necessary product separations / fractionation and possibly product refining thereof to yield the hydrocarbon intermediate B. Isosynthesis reaction as such refers to catalytic hydrogenation of carbon monoxide under suitable choice of isosynthesis reaction conditions, leading principally to production of a branched olefinic hydrocarbon isobutene, which is further oligomerized to trimers and tetramers. Additionally, some paraffinic hydrocarbons and higher alcohols can be produced in an isosynthesis reaction. As such, the catalytic isosynthesis is described in detail in e.g. FI20235260, the contents of which are herein incorporated by reference. As used herein, the “methanol synthesis and upgrading process” refers to reacting a gas comprising CO2 with H2 or CO with H2 to produce methanol, followed by conversion of methanol to olefins to obtain the desired carbon numbers for SAF components by oligomerization. The methanol synthesis and upgrading process further comprises necessary separations and possible further refining thereof to provide the hydrocarbon intermediate B. The methanol synthesis and upgrading processes are known to a man skilled in the art (see, e.g. https: / / en.wikipedia.org / wiki / Methanol or Gogate, M., Methanol-to-olefins process technology: current status and future prospects, Petroleum Sci and Tech., (37) 2019 559-565). Some processes are currently commercially available.

[0049] As used herein, “degassed” refers to an effluent that has been subjected to gas-liquid separation and from which at least species that are gaseous at NTP (normal temperature and pressure) have been separated or removed. For example, such degassed effluents include degassed hydrocracking effluent. Further, for the purpose of analyses, any stream, effluent, product or sample analyzed for any physico-chemical or a compositional characteristic, is in practice degassed prior to conducting any analysis. In practical language, they would be understood as a “liquid” stream, effluent, product or sample, respectively. The fraction separated from said degassed effluents, typically C1- C4 such as propane, may be referred to as “gaseous phase” or “gaseous fraction” of the respective effluent. Further, where any stream, effluent, product or sample is characterized by corresponding parameters, the numbers are given relative to the degassed weight or volume.

[0050] As used herein hydrocarbons refer to compounds consisting of carbon and hydrogen, and comprise e.g. paraffins, n-paraffins, isoparaffins (monobranched and / or multiple-branched isoparaffins), olefins, naphthenes, and aromatic hydrocarbons. Oxygenated hydrocarbons refer herein to hydrocarbons comprising covalently bound oxygen.

[0051] As used herein paraffins refer to non-cyclic alkanes, i.e. non-cyclic, open chain saturated hydrocarbons that are linear (normal paraffins, n-paraffins) or branched (isoparaffins, i-paraffins). In other words, paraffins refer herein to n-paraffins and / or isoparaffins.

[0052] In the context of the present disclosure, isoparaffins (or i-paraffins) refer to branched open chain alkanes, i.e. non-cyclic, open chain saturated hydrocarbons having one or more alkyl side chains. Herein, isoparaffins having one alkyl side chain or branch are referred to as monobranched isoparaffins and isoparaffins having two or more alkyl side chains or branches are herein referred to as multiple-branched isoparaffins. In other words, isoparaffins refer herein to monobranched isoparaffins and / or multiple-branched isoparaffins. The alkyl side chain(s) may for example be C1 - C9 alkyl side chain(s), preferably methyl side chain(s). The amounts of monobranched and multiple-branched isoparaffins may be given separately. The term “isoparaffins” refers to sum amount of any monobranched isoparaffins and multiple-branched isoparaffins, if present, indicating the total amount of any isoparaffins present regardless of the number of branches. Correspondingly, “paraffins” refers to sum amount of any n-paraffins, any monobranched isoparaffins, and any multiple-branched isoparaffins, if present.

[0053] In the context of the present disclosure, olefins refer to unsaturated, linear, branched, or cyclic hydrocarbons, excluding aromatic compounds. In other words, olefins refer to hydrocarbons having at least one unsaturated bond, excluding unsaturated bonds in aromatic rings.

[0054] As used herein, cyclic hydrocarbons refer to all hydrocarbons containing cyclic structure(s), including cyclic olefins, naphthenes, and aromatic hydrocarbons. Naphthenes refer herein to cycloalkanes (cycloparaffins) i.e. saturated hydrocarbons containing at least one cyclic structure, with or without side chains. As naphthenes are saturated compounds, they are compounds without aromatic ring structure(s) present. Aromatic hydrocarbons refer herein to hydrocarbons containing at least one aromatic ring structure, i.e. cyclic structure having delocalized, alternating IT bonds all the way around said cyclic structure.

[0055] In the context of this disclosure, CX+ carboxylic acids, CX+ fatty acids, CX+ hydrocarbons, CX+ paraffins, or CX+ isoparaffins refer to carboxylic acids, fatty acids, hydrocarbons, paraffins, or isoparaffins, respectively, having a carbon number of at least X, where X is any feasible integer. The same is meant when referring to corresponding compounds giving the lower limit, i.e. CX and higher carbon number compounds respectively.

[0056] As used herein, the term ’’free fatty acids (FFAs)” refers to an organic acid that contains a carboxyl group (-COOH) attached to an R alkyl group which has one or more carbons. Esters of fatty acids refer to fatty acid derivatives derivative of fatty acids in which the hydrogen atom of the hydroxyl group has been replaced with an alkyl group R’, the ester having the structure R-COO-R’, wherein the R’ is an alkyl chain comprising one or more carbons.

[0057] As used herein, fatty acids are produced from renewable feedstock comprising triglycerides by hydrolysis. Fatty acids are preferred over renewable feedstock comprising triglycerides as feed to hydrocracking process.

[0058] As used herein, the term ’’triglycerides” refers to an ester derived from glycerol and three fatty acids.

[0059] In the context of the present disclosure, the “overall process” refers to a combination of the subprocesses A and B, which are integrated to share at least an isomerization step. As used herein, streams from neighboring processes e.g. from the same refinery, preferably low-value streams, may be combined with those originating from different parts of the overall process and which chemically and reactively resemble one another. Such low-value streams from neighboring processes are referred to as “additional” feeds to unit processes, such as "additional” glycerol to reforming, such as steam reforming, refers to glycerol originating from another process which is combined with glycerol separated from a hydrolysis step h) of sub-process A.

[0060] The disclosure relates to a process for producing fuel components for sustainable aviation fuel (SAF) from a renewable feedstock comprising triglycerides.

[0061] The process for producing fuel components for SAF from a renewable feedstock comprising triglycerides comprises a sub-process A for converting the renewable feedstock to a hydrocarbon intermediate A. The process for producing fuel components for SAF from a renewable feedstock comprising triglycerides also comprises a sub-process B for converting products obtained from the sub-process A to a hydrocarbon intermediate B. The process for producing fuel components for SAF from a renewable feedstock comprising triglycerides also comprises the step i) comprising isomerizing the hydrocarbon intermediate A and the hydrocarbon intermediate B, to obtain at least a SAF component comprising C9-C17 hydrocarbons. The sub-processes A and B are thus integrated through at least the step i).

[0062] In an embodiment the overall process for producing fuel components for SAF from a renewable feedstock comprising triglycerides, comprises sub-processes A and B and an isomerization step, here referred to as the isomerization step i).

[0063] The sub-processes A and B are further integrated through exchange of process streams between the sub-processes A and B. The exchange of process streams between the sub-process A and B takes place as the sub-process B utilizes glycerol from the step h) of the sub-process A, to obtain a gas mixture to a carbon refining step c). The exchange of process streams between the sub-process A and B takes place also as the sub-process B utilizes light hydrocarbons and oxygenates obtained from a step he) of the sub-process A, to obtain a gas mixture to a carbon refining step c).

[0064] In an embodiment, the integration of the sub-process A and B takes place as the sub-process A utilizes heavy hydrocarbons obtained from the synthesis step s) of the sub-process B, to be further hydrocracked at the step he). Integrating the sub-processes A and B is beneficial, as it provides an opportunity to efficiently utilize all the products obtainable from the renewable feedstock, during different process steps. Integration is further beneficial, as the combination of the sub-process A and B products provide a SAF component with beneficial carbon distribution influencing, for example, the cold viscosity properties of the SAF component.

[0065] According to certain embodiments of the process, the sub-processes A and B may be further integrated through further unit operations, wherein streams originating from one sub-process are refined, utilized and / or upgraded in the other sub-process advantageously reducing loss of carbon and hydrogen, and at the same time increasing the yield of most valuable products obtainable from the process. The greatest interest is to utilize carbon streams as effectively as possible. Accordingly, at least one

[0066] - stream comprising light hydrocarbons (C1- C7) and oxygenates obtained from the step he);

[0067] - a glycerol stream obtained from the step h); and

[0068] - a heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons obtained from step s), are exchanged between sub-processes A and B. Said exchanges are discussed in detail in relation to an appended figure.

[0069] In an embodiment, the sub-processes A and B are integrated, as both processes comprise or share at least an isomerization step. In an embodiment, the sub-processes A and B are integrated, as both processes share the same unit for the isomerization step.

[0070] As used here, “the sub-process A” refers to a sequence of reactions converting the renewable feedstock comprising triglycerides to a “hydrocarbon intermediate A”, hence reacting the triglycerides through hydrolysis and thereafter through hydrocracking reactions to hydrocarbons. The sub-process A is considered to be the main route of the process disclosed herein, because it preferably produces the majority (by mass) of the sustainable aviation fuel or the SAF component obtainable from the overall process. Thus, with regard to mass flows, sub-process A is preferably the most significant route. In an embodiment, sustainable aviation fuel and / or sustainable aviation fuel component is obtained from the present process.

[0071] In an embodiment, the process comprises the sub-process A which comprises: h) subjecting the renewable feedstock to hydrolysis in the presence of water to produce glycerol, water and fatty acids, thereby obtaining an oil phase and an aqueous phase; he) subjecting the oil phase comprising fatty acids obtained in the hydrolysis at the step h) to hydrocracking, to obtain light hydrocarbons, oxygenates, and the hydrocarbon intermediate A suitable for isomerization.

[0072] In an embodiment, in addition to the hydrolysis step h) and the hydrocracking step he), subprocess A can contain further steps, such as product separations / fractionation.

[0073] The step h) of sub-process A comprises subjecting the renewable feedstock comprising triglycerides to hydrolysis. As to chemistry, hydrolysis of triglycerides (as well as diglycerides and monoglycerides) eventually releases free fatty acids and glycerol. Hydrolysis contributes to the hydrocracking step he), by providing fatty acids as the predominant feed instead of triglycerides. Hydrolysis takes place in the presence of water, typically excess water. From the hydrolysis reactor, the aqueous phase comprising glycerol and water, and the oil phase comprising fatty acids and possible further lipids and / or oily compounds are recovered. Thus, the aqueous phase comprises at least glycerol and water and the oil phase comprises at least fatty acids. The oil phase and the aqueous phase are separable by conventional means for liquid-liquid separation. In an embodiment, the step h) comprises also liquid-liquid separation of the oil phase and the aqueous phase. Means for said liquid-liquid separation are known in the art.

[0074] In an embodiment, the step h) comprises subjecting the renewable feedstock comprising triglycerides to hydrolysis in the presence of water to obtain the oil phase comprising fatty acids and the aqueous phase comprising glycerol and water. In an embodiment, the aqueous phase comprises water, glycerol and any water soluble or miscible impurities from the initial renewable feedstock. Hence, the hydrolysis step h) and the subsequent liquid-liquid separation contribute to the purification of the renewable feedstock comprising triglycerides. Pre-treatment needs of a renewable feedstock will be reduced since hydrolysis step of triglycerides will simultaneously purify renewable feedstock. Therefore, the hydrolysis step h) at the beginning of the disclosed process is beneficial at least because it purifies the oil phase comprising fatty acids, which are directed to the hydrocracking reaction of the step he). A further advantage of hydrolysis step h) is that separation of glycerol from the main route of the sub-process A enables it to be directed to the sub-process B, subjected to reforming and further steps, and eventually contributing to the yield of the overall process.

[0075] Fats and oils are made up of triglycerides (triacylglycerols). Triglycerides contain 3 ester functional groups. Hydrolysis is a reaction with water. Hydrolysis is an equilibrium reaction. Acid hydrolysis of a triglyceride produces glycerol and three fatty acids. The hydrolysis reaction is acid catalytic, but it can be done also with enzymes. If base is used as a catalyst in hydrolysis reaction, it results in soaps of fatty acids, which have to be acidulated with strong acid (such as sulfuric acid) afterwards back to free fatty acids. Typical hydrolysis reactions are depicted in the following scheme 1 .

[0076] Scheme 1 . Hydrolysis reactions. Preferably the hydrolysis is conducted following the Colgate-Emery process, in which typical temperature and pressure conditions are around 250 °C and 5 MPa. Using a two-hour reaction time, typical FFA yield is 97 %.

[0077] Hydrolysis as such is known as an exothermic process. Nevertheless, vaporizing the water for the hydrolysis process consumes energy, as does the oil / aqueous phase separation after hydrolysis. According to an embodiment, energy recovered from another part of the overall process, such as the synthesis step s), may be returned and utilized in the hydrolysis step h). In an embodiment, the energy recovered from another part of the overall process is used in the exothermic hydrolysis reaction. In an embodiment, the energy recovered from another part of the overall process is used in the liquid-liquid separation of the hydrolysis product into the oil and aqueous phase.

[0078] Several hydrolysis methods have been developed, including, but not being limited to, acidic / alkaline-catalyzed, lipase-catalyzed, and catalyst-free hydrolysis methods. Another hydrolysis option is a so-called subcritical water hydrolysis, as it carries out efficient hydrolysis of triglycerides, but also simultaneously purifies the treated oil, therefore helping further catalytic processing. The reaction conditions for hydrolysis can be selected from a temperature between 270 to 350 °C, a pressure from 10 to 20 MPa, and residence time from 5 min to 30 min. Additional benefit of this subcritical water hydrolysis is to achieve the hydrolysis of amides, which can be difficult to hydrotreat.

[0079] In an embodiment, the composition of the oil phase obtained from the hydrolysis reaction is characterized by comprising free fatty acids having the carbon number from C14 to C22 and / or other organic acids having carbon numbers from C14 to C22. Further organic acids are for example resin acids. Residues from incomplete hydrolysis can be seen in the oily phase as glycerides (mono, di and / or tri). However, said composition of the oil phase is dependent on the initial renewable feedstock comprising triglycerides, eventual further feedstocks or co-feeds and the hydrolysis reaction conditions. In an embodiment, the oil phase comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-% of organic acids, preferably free fatty acids (FFAs), of the total weight of the oil phase.

[0080] After the step h) the oil phase comprising fatty acids obtained therefrom, is subjected to hydrocracking reactions at the step he) to obtain light hydrocarbons, oxygenates, and the hydrocarbon intermediate A suitable for isomerization. In practice in terms of carbon numbers, the oil phase typically comprises a range of different fatty acids. Further, the fatty acids of the oil phase may be saturated or unsaturated. In an embodiment, the fatty acids entering the hydrocracking reaction of the step he) have carbon numbers typically from C14 to C22. As a minor amount, some triglycerides, diglycerides and / or monoglycerides may be present as well. Nevertheless, the carbon number distribution is dependent on the renewable feedstock comprising triglycerides and properties thereof. In an embodiment, the process comprises: step he) directly after the step h), without any intermediate processing steps, after said step h). In an embodiment, at least part of the oil phase obtained from the step h) is directed from the step h) directly into the hydrocracking of the step he).

[0081] Hydrocracking reactions of the step he) refer to catalyzed cracking reactions under hydrogen pressure. In hydrocracking, the fatty acid molecules will split to hydrocarbons having a lower carbon number compared to the fatty acids in the feed entering the reaction. Depending on the choice of the hydrocracking catalyst, the cracking reactions and thus the hydrocarbon distribution can be selectively adjusted. Besides hydrocarbons, at least oxygenates comprising H2O are formed in hydrocracking.

[0082] In an embodiment, the hydrocracking is carried out in the presence of a bifunctional hydrocracking catalyst comprising a metal site and an acid site. In an embodiment, the bifunctional hydrocracking catalyst is selected from one or more of: platinum, palladium, ruthenium, nickel, molybdenum, cobalt, tungsten, or any combination thereof. In an embodiment, the bifunctional hydrocracking catalyst comprises a noble metal or a group VIA metal, such as molybdenum or tungsten, together with a group VII IA metal, such as cobalt or nickel. In an embodiment, the hydrocracking catalyst is Ni / W, Ni / Mo, Co / Mo, Pt Ru or Pd.

[0083] In an embodiment, the hydrocracking is carried out in the presence of an acidic hydrocracking catalyst support. Acidity of the hydrocracking catalyst support is important for the function of the hydrocracking process. In an embodiment, the said acidic support is selected from one or more of alumina / chlorided alumina, amorphous silica alumina (ASA), zeolite and a binder. In an embodiment, the said acidic support is selected from one or more of SiC>2, AI2O3 and zeolites, such as beta-zeolites.

[0084] In an exemplary embodiment, the hydrocracking catalysts are sulphurized NiMo / NiW or noble metal on zeolite-based catalysts on acid support. In an embodiment, additional hydrogen gas is fed into the hydrocracking he) process. Said additional hydrogen may be produced e.g. by electrolysis.

[0085] The hydrocracking can also be carried out at mild hydrocracking reaction conditions, such as at a pressure of about 35 - 70 bar, a temperature of about 325 - 375 °C, a WHSV of about 0.5 - 3.0 h-1, and a H2 feed ratio of about 250-500 nl H2 / liter of the feed.

[0086] In an exemplary embodiment, the hydrocracking typically comprises hydrogen pressure above 5 MPa and reaction temperatures are above 350°C.

[0087] Hydrocracking conversion can be set to about 95 wt-% of the total weight of the feed to be hydrocracked. Hydrocracking selectivity to SAF component boiling range is set to at least 50 wt- % of the total weight of converted hydrocracked effluent. Moreover, in some embodiments, the converted hydrocracked effluent may comprise more than 50 wt-% of hydrocarbons suitable for the SAF component, from the total weight of the converted hydrocracked effluent.

[0088] Some renewable feedstocks may comprise a large relative portion of triglycerides with a carbon number > C17, such as rapeseed oil, Brassica Carinata, and some fish oils, which restricts their efficient use in a renewable aviation SAF production, due to the properties of formed n-paraffins and i-paraffins affecting, for example, the boiling point range, cold flow properties, density, and cold viscosity of the final SAF component. The portion of C18 hydrocarbons in the SAF component is limited by the boiling range set for the SAF components as set out in the product requirements in the ASTM D7566-22 Annex 2. Only a very limited amount of C18 hydrocarbons may be comprised in the SAF component, depending on its desired properties. Therefore, the carbon number of hydrocarbons obtained from such feedstocks must be reduced, the resulting SAF component to fulfill the product criteria set out in the ASTM D7566-22 Annex 2.

[0089] Therefore, the hydrocracking step he) is beneficial, as the carbon number of the > C17 fatty acids comprised in the hydrolyzed feedstock arriving from the step h) is reduced by hydrocracking, the carbon number distribution of the resulting hydrocarbon intermediate A thus being suitable for the SAF component. With the selection of reaction conditions and catalyst properties, hydrocracking reactions can be enhanced and the distribution of hydrocarbons to broaden the carbon number range of the hydrocracked product is achieved. Further, hydrocracking of fatty acids forms cyclic (naphthenic and aromatic) compounds that have beneficial impact to SAF properties, such as on cold viscosity. The hydrocarbon intermediate A obtained from the hydrocracking step he) has a broad hydrocarbon distribution and comprises cyclic hydrocarbons, which contribute to the beneficial properties of the SAF component. Said beneficial properties are discussed for example in FI20235691.

[0090] In some embodiments, the carbon number of also at least a portion of the C17 fatty acids comprised in the hydrolyzed feedstock arriving from the step h) is further reduced by hydrocracking. Also the portion of C17 hydrocarbons in the SAF component is limited by the boiling range set for the SAF components as set out for the product requirements in the ASTM D7566-22 Annex 2.

[0091] In hydrocracking process, light hydrocarbons and oxygenates are also obtained. In an embodiment, the light hydrocarbons obtained at the step he) comprise C1 - C7 hydrocarbons, and the oxygenates obtained at the step he) comprise one or more of water, light alcohols, ketones and aldehydes. These fractions are beneficial, as these provide feedstock to the subprocess B, and thus, contribute to the carbon and hydrogen efficiency of the final products obtained from the process. In an embodiment, the light hydrocarbons obtained at the step he) comprise C1 - C7 hydrocarbons, which are provided to the reforming step r). In an embodiment, the light hydrocarbons obtained at the step he) and provided to the reforming step r), comprise preferably mainly C1 - C4 hydrocarbons, more preferably C1 - C3 hydrocarbons, even more preferably mainly C1 - C2 hydrocarbons, most preferably mainly C1 hydrocarbons.

[0092] In an alternative embodiment, at least part of the light hydrocarbons comprising C2 - C7 hydrocarbons are utilized elsewhere than in the reforming step r). Therefore, in some embodiments, at least part of the light hydrocarbons comprising C2 - C7 hydrocarbons are recovered from the step he) to be utilized in the chemical industry. In other embodiments, at least part of the light hydrocarbons comprising C2 - C7 hydrocarbons are recovered from the step he) to be recycled elsewhere in the process.

[0093] The amount of gaseous light C5 - C7 hydrocarbons entered in the isomerization process is limited, and thus, majority of the light hydrocarbons C5 - C7 should be rather directed to the reforming process r) or removed from the process at the step he). In other embodiments, at least part of the light hydrocarbons C5- - C7, making up a naphtha fraction, are recovered from the step he) to be utilized elsewhere.

[0094] In an alternative embodiment, at least part of light C1 - C2 hydrocarbons are recovered from the step he) and directed to the carbon refining step c).

[0095] In an embodiment, the oxygenates obtained at the step he) comprise water, light alcohols, ketones and aldehydes. Preferably, the oxygenates obtained at the step he) comprise mainly water.

[0096] In an embodiment, also carbon oxides (CO and / or CO2) are obtained at the hydrocracking of the step he). Carbon oxides can be provided to the reforming step r). Thus, in some embodiments, the oxygenates obtained at the step he) comprise carbon oxides, such as CO and / or CO2. In an embodiment, the oxygenates obtained at the step he) and provided to the reforming step r), comprise at least one of H2O, CO2, CO, methanol, and acetone.

[0097] In an embodiment of the current process, hydrogenation of unsaturated hydrocarbons comprising olefin bonds which are present in the oil phase, takes place during the hydrocracking step he), or before or after said he) step, in a separate hydrogenation step. Thus, most of the olefins are hydrogenated, and at the same time most e.g. organo-nitrogen compounds are removed. This is advantageous for maintaining acid sites and increasing conversion of hydrocracking.

[0098] In an embodiment, hydrogenation of unsaturated hydrocarbons comprising olefin bonds which are present in the oil phase, takes place after the hydrolysis step h) and before the hydrocracking step he) in a separate hydrogenation step. In such an embodiment, the hydrogenation of olefins produces some of the thermal energy required for the hydrocracking reaction (an endothermic reaction). In an embodiment, the hydrocracking of the step he) hydrogenates at least part of the olefins and aromatics present in the feed entering the step he). In an embodiment, hydrogenation of unsaturated hydrocarbons comprising olefin bonds which are present in the hydrocarbon intermediate A, takes place after the hydrocracking step he) in a separate hydrogenation step. Minimizing the presence of unsaturated hydrocarbons contributes to avoidance of premature isosynthesis catalyst deactivation.

[0099] In one embodiment, in the current process hydrogenation of any unsaturated hydrocarbons comprising olefin bonds present in the oil phase is not necessary prior to the hydrocracking step he). In some embodiments, the hydrocarbon intermediate A entering the isomerization step i) comprises aromatic compounds, preferably monoaromatics. Aromatic compounds in the hydrocarbon intermediate A entering the isomerization step i) may be beneficial, as these are mostly hydrogenated into naphthenic compounds during the isomerization step i), which are beneficial for the final SAF component properties. This is advantageous also for the hydrogen efficiency of the overall process, as unnecessary hydrogenation steps(s) and thus, hydrogen consumption can be avoided.

[0100] In an embodiment, the hydrocarbon intermediate A comprises paraffins suitable for isomerization and / or cyclic hydrocarbons, such as naphthenic and aromatic hydrocarbons.

[0101] Correspondingly, in an embodiment, the hydrocarbon intermediate A obtainable from the hydrocracking step he) comprises mostly saturated hydrocarbons, said hydrocarbons comprising predominantly saturated linear C9 to C17 hydrocarbons. According to an embodiment, the hydrocarbon intermediate A comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-% of C9 to C17 hydrocarbons, of the total weight of the hydrocarbon intermediate A. According to an embodiment, the hydrocarbon intermediate A comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-% of C9 to C17 n-paraffins, of the total weight of the hydrocarbon intermediate A. Said hydrocarbons may also comprise n- olefins with carbon number from C9 to C17 as minor amounts.

[0102] When eventually isomerized, such hydrocarbon intermediate provides an advantageous sustainable aviation fuel component composition.

[0103] In an embodiment, the hydrocarbon intermediate A comprises at least 10 wt-% cyclic hydrocarbons, comprising naphthenes and aromatic compounds. In an embodiment, the hydrocarbon intermediate A comprises at least 5 wt-% naphthenic hydrocarbons. In an embodiment, the hydrocarbon intermediate A comprises at least 0.5 wt-% of cyclic hydrocarbons, such as aromates. Naphthenic and aromatic compounds have a beneficial impact on SAF properties. The quantity of naphthenic and / or aromatic compounds in the hydrocarbon intermediate A depends on the composition of the initial renewable feedstock provided, and / or on the used hydrocracking reaction conditions. In some embodiments, the cyclic hydrocarbons comprised by the hydrocarbon intermediate A, are mostly only naphthenes. When eventually further isomerized, the hydrocarbon intermediate A provides an advantageous sustainable aviation fuel component composition.

[0104] In an embodiment, the process comprises the sub-process B which comprises: r) reforming the glycerol obtained from the aqueous phase from step h) and light hydrocarbons and oxygenates obtained from the step he), into a gas mixture comprising carbon oxide(s) and hydrogen.

[0105] The sub-process B can be seen complementing the sub-process A and providing further appropriate-sized hydrocarbons as feed to isomerization process of the step i). The main purpose of the sub-process B is to convert at least the light hydrocarbons and oxygenates from the step he) to a hydrocarbon intermediate B. Its further purpose is to convert at least the glycerol from the step h) to a hydrocarbon intermediate B. However, compiling further streams, such as short chain hydrocarbons and oxygenates from other process steps is also possible. Compiling said further streams is beneficial, as it contributes to carbon efficiency of the process and thus to higher yield of the SAF component and thereby to the process synergy.

[0106] The sub-process B comprises at least the steps r) reforming, c) carbon refining, and step s) hydrocarbon synthesis, yielding a hydrocarbon intermediate B.

[0107] The step r) reforming precedes said step c) carbon refining. As a feed to said reforming, at least glycerol recovered from the hydrolysis step h) is used. Glycerol reacts to provide carbon oxides and hydrogen as products of the reforming. In an embodiment, the reforming at the step r) comprises reforming the glycerol obtained from the aqueous phase from the step h) and gaseous products obtained from the step he), into a gas mixture comprising carbon oxide(s) and hydrogen.

[0108] Reforming may include steam reforming (SR) or dry reforming (DR), and for example partial oxidation reforming (POR), autothermal reforming (ATR), aqueous phase reforming (APR), and supercritical water reforming (SCWR). Preferably, the reforming is steam reforming. Several alternatives for glycerol reforming are known in the art

[0109] SR is employed industrially for the production of hydrogen, but it also produces a synthesis gas mixture that is rich in hydrogen (CH4+ H2O «-> CO + 3H2). H2 production may be enhanced, when the resulting gas is separated, and CO is reacted further with H2O via water-gas shift reaction CO + H2O CO2+ H2.

[0110] DR i.e. carbon dioxide reforming, is an endothermic reaction (CH4+CO2 2CO+2H2) between hydrocarbons, such as methane, and carbon dioxide for the production of a mixture of CO and hydrogen, i.e. synthesis gas, with the aid of metal catalysts, such as Fe, Co, Ni, Pt, Pd, Ru, Rh and Ir. Typically, synthesis gas is produced by steam reforming reaction or coal gasification. However, present concerns on the contribution of greenhouse gases to global warming have increased interest in the replacement of steam as reactant with carbon dioxide. It is advantageous to add also the hydrocracking step he) process gases comprising the light hydrocarbons, oxygenates optionally comprising small amounts of carbon oxides to the reforming step r). The reforming, such as steam reforming, will have beneficial yield to the subsequent synthesis step s) gas, when the reforming feed comprises both, the glycerol from step h) and hydrocracking process gases from the step he), preferably comprising at least water and C1 hydrocarbons. Thereby, these at least two streams from the sub-process A are processed together to increase the overall synthesis gas yield.

[0111] A gas mixture comprising hydrogen and carbon oxide(s) is obtained from the reforming step r). In an embodiment, the sub-process B comprises step c) subjecting the gas mixture comprising carbon oxide(s) and hydrogen from step r) to carbon refining, to obtain a gas mixture comprising carbon monoxide and hydrogen gas.

[0112] The sub-process B comprises the step c), subjecting carbon oxide(s) obtained from the reforming step r) to carbon refining step c), to obtain a gas mixture. The aim of the carbon refining step is to adjust the composition of the gas to suit best the selected hydrocarbon synthesis in the following step s). Thus, at the carbon refining step c), the ratio of the carbon oxide(s) and hydrogen from step r) is adjusted. Effective use of the light hydrocarbons and oxygenates originating from the renewable feedstock comprising triglycerides contributes to the overall carbon efficiency of the present process. Dependent on the selected hydrocarbon synthesis at the step s) applied, the requirements for the adjusting of the carbon refining step c) vary, leading to hydrocarbon synthesis step s) -specific gas compositions.

[0113] A gas mixture comprising hydrogen and carbon monoxide is obtained from the carbon refining step c). In an embodiment, the carbon refining of the step c) comprises adjusting a hydrogen / carbon monoxide ratio of the gas mixture obtained from the step r), preferably said adjusting is carried out by water gas shift (WGS) reaction. In some embodiments, said adjusting is carried out by adding to the gas mixture sustainable hydrogen produced via water electrolysis.

[0114] In an embodiment, the adjusting of the hydrogen / carbon monoxide ratio of the gas mixture is conducted by a water gas shift reaction (CO + H2O «-> CO2 + H2) which is known in the art. In an embodiment, the carbon refining in the step c) comprises adjusting the hydrogen / carbon monoxide ratio of said gas mixture from step r) by adding hydrogen, such as sustainable hydrogen produced via water electrolysis. In an embodiment, additional synthesis gas may be added to the gas mixture, thereby adjusting the hydrogen / carbon monoxide ratio of the gas mixture obtained from the step r). Moreover, some formed water may need to be removed from the carbon refining step c) product. Furthermore, a combination of the described processes may be applied.

[0115] In an embodiment, step c) comprises feeding additional hydrogen to the adjusting of the hydrogen / carbon monoxide ratio. Said additional hydrogen may be produced e.g. by electrolysis. In some embodiments, also additional carbon oxide(s) are fed to the step c), for adjusting the hydrogen / carbon monoxide ratio.

[0116] Further, as the reforming and the water gas shift are equilibrium reactions, this means that gases from both sides of the reaction equation are present (in addition to the gas components most desirable as products).

[0117] In an embodiment, the step c) comprises adjusting the hydrogen / carbon monoxide ratio of the gas mixture comprising carbon oxide(s) and hydrogen to be suitable for a Fischer-Tropsch process. Where the hydrocarbon synthesis step s) is a Fischer-Tropsch process, the gas fed thereto from step c) should comprise hydrogen gas and carbon monoxide (CO) gas, preferably in such proportions that the hydrogen to carbon monoxide ratio is about 1 .7 or higher.

[0118] In embodiments, where the synthesis step s) is isosynthesis, process the gas fed thereto is also a mixture of carbon monoxide (CO) gas and hydrogen gas. More specifically, the synthesis gas (syngas) for isosynthesis process comprises primarily carbon monoxide and hydrogen but may further include carbon dioxide and / or minor amounts of other gases such as methane, as well. Preferably the synthesis gas comprises 20 mol-% - 60 mol-% of carbon monoxide and 40 mol-% - 70 mol-% of hydrogen.

[0119] In embodiments, where the synthesis at the step s) is conducted through a methanol synthesis and upgrading, the gas fed thereto comprises CO2 with H2 or CO with H2.

[0120] In the hydrocarbon synthesis step s) the gaseous compounds comprising carbon monoxide and hydrogen gas from carbon refining c) are subjected to hydrocarbon synthesis wherefrom C8 - C16 hydrocarbons may be recovered as hydrocarbon intermediate B. The side streams from the sub-process A, otherwise of low value, can thus be refined to contribute to the overall sustainable aviation fuel yield.

[0121] In embodiments, the gas fed from carbon refining step c) to the hydrocarbon synthesis step s) has adequate purity, and thus, no additional feed purification is thus necessary.

[0122] In an embodiment, the sub-process B comprises the hydrocarbon synthesis step s). The hydrocarbon synthesis step s) is herein defined as subjecting the gas mixture comprising the carbon monoxide and hydrogen gas to hydrocarbon synthesis step selected from a Fischer- Tropsch process, isosynthesis process or methanol synthesis and upgrading process, and recovering the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from the hydrocarbon synthesis effluent.

[0123] Fischer Tropsch (FT) process as the hydrocarbon synthesis step s) reaction converts synthesis gas to hydrocarbons and water. The reaction is exothermic. The technology is available commercially. Where the synthesis step s) is a Fischer-Tropsch process, the reaction conditions may be selected from typical reaction temperatures 200 - 300 °C and typical pressures below 100 bar. In an embodiment wherein the synthesis step is the FT process, the hydrocarbon synthesis effluent obtained from the FT process comprises n-paraffins within broad carbon number range. According to a preferred embodiment, the FT conditions are set to provide increased productivity within a JET selective product range. In an embodiment, a fraction comprising n-paraffins having carbon numbers from C8 - C16 is obtained from FT synthesis which can be readily fed to the isomerization as hydrocarbon intermediate B. Said hydrocarbons when obtained from FT process are predominantly n-paraffins.

[0124] In embodiments, where the hydrocarbon synthesis is isosynthesis process, the hydrocarbon synthesis step s) comprises reacting the gas mixture catalytically to produce an isosynthesis reaction product comprising isobutene monomers. The isosynthesis process is carried out in the presence of an isosynthesis catalyst and the reaction conditions may be selected from a temperature from 300 to 500 °C, and a pressure from 20 to 100 bar. Preferably the reaction is carried out as an isosynthesis single pass conversion within the range from 20 % to 80 %.

[0125] In the embodiment wherein the hydrocarbon synthesis s) is isosynthesis process, the obtained isobutene monomers from the isosynthesis reaction are further oligomerized in the step s) into an oligomerized product containing at least trimers of isobutene and tetramers of isobutene, to provide carbon numbers suitable for SAF components. For instance, FI20216108 or FI20235260 disclose in detail processes for manufacturing olefin trimers and tetramers by oligomerizing olefin monomers. The oligomerized product is further hydrogenated as part of the hydrocarbon synthesis step s), thereby obtaining the hydrocarbon intermediate B.

[0126] In the embodiment wherein the hydrocarbon synthesis step s) is isosynthesis process, hydrocarbon intermediate B comprises n-paraffins, predominantly within carbon number range from C12 to C16.

[0127] In an embodiment where the synthesis is conducted through a methanol synthesis and upgrading process, the reaction proceeds through ethene and / or propene and butenes formation which then are oligomerized to provide hydrocarbons with desired carbon numbers. Several methanol synthesis and upgrading processes are known to a man skilled in the art. See e.g. Shutao Xu, at al., Advances in Catalysis for Methanol-to-Olefins Conversion, in Advances in Catalysis, Vol. 61 , 2017, Pages 37-122, which is hereby incorporated by a reference. Processes are currently commercially available.

[0128] From the effluent of the hydrocarbon synthesis of the step s), a hydrocarbon intermediate B is recovered by conventional means. In embodiments where further fractions are recovered, they can be directed or recycled to appropriate steps.

[0129] In an embodiment, at least one further fraction is recovered from the step s), the at least one further fraction being selected from: • a naphtha fraction comprising C5 - C7 hydrocarbons,

[0130] • a heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons,

[0131] • a light fraction comprising C1 - C4 hydrocarbons,

[0132] • an oxygenate fraction comprising water, and

[0133] • combinations thereof.

[0134] In an embodiment, the at least one further fraction recovered from the step s) comprises naphtha fraction comprising C5 - C7 hydrocarbons, which can be utilized, for example in other processes. In a preferred embodiment, the naphtha fraction comprises mainly C5 - C6 hydrocarbons. In an embodiment, the at least one further fraction recovered from the step s) comprises a fuel gas product comprising C3-C4 hydrocarbons.

[0135] In an embodiment, the at least one further fraction recovered from step s) comprises the heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons. In an embodiment, at least part of the heavy hydrocarbon fraction recovered from the step s) is directed to hydrocracking of the step he). Hence, n-paraffins having carbon numbers C17+ can be recovered and fed to hydrocracking step he), to further contribute to the SAF component yield. This is beneficial, as this allows efficient utilization of also the C17+ n-paraffins in the SAF component.

[0136] According to an alternative embodiment, said heavy hydrocarbon fraction comprising C17+ hydrocarbons, obtained in step s) is fed to the isomerization step i). Feeding this stream to the step i) contributes to the overall sustainable aviation fuel yield. In the hydroisomerization reactions together with hydrocracking as a minor side reaction, the heavy end hydrocarbons, especially C17, and even C18, or even some C18+, are converted either to i-paraffins fitting into SAF component composition or if higher carbon numbers, to i-paraffins having added value as isomerized heavy hydrocarbons. In the hydroisomerization reactions comprising hydrocracking as a minor side reaction, the heavy end hydrocarbons can be converted suitable for the SAF boiling range through selective cracking, as longer hydrocarbon chains crack more easily than shorter ones.

[0137] In an embodiment, the at least one further fraction recovered from step s) is a light hydrocarbon fraction comprising C1 - C4 hydrocarbons, which can be directed to the reforming step r). This is beneficial for the hydrogen efficiency of the overall process, as when fed to reforming, such as steam reforming, unit the light hydrocarbon fraction will enhance the production of hydrogen and carbon oxide(s). Obtaining the light hydrocarbon fraction comprising C1 - C4 hydrocarbons from the step s) is also beneficial as the reforming gas composition can this way be adjusted, to shift the equilibrium of the composition towards beneficial H2 / CO ratio suited to the selected hydrocarbon synthesis s) process, such as Fischer Tropsch process. In a preferred embodiment, the light hydrocarbon fraction recovered from step s) and directed to the reforming step r) comprises mainly C1-C2 hydrocarbons, even more preferably only C1 hydrocarbons. In an embodiment, the at least one further fraction recovered from step s) is the oxygenate fraction comprising water. In an embodiment, at least part of the oxygenate fraction comprising water, recovered from the step s), is directed to reforming of the step r). In an embodiment, the oxygenate fraction comprising water further comprises other light oxygenates.

[0138] In embodiment of the process, several feeds or side streams obtained in the process are directed to other steps of the process, the steps of the process for producing fuel components for SAF thus being integrated, also within the sub-processes A and B. For example, the reforming step r) may be integrated to several of the other process steps.

[0139] In an embodiment, the step r) comprises feeding in the reforming one or more of:

[0140] • glycerol and water obtained at the step h),

[0141] • the light hydrocarbons obtained at the step he);

[0142] • the oxygenates obtained at the step he);

[0143] • the light fraction comprising C1 - C4 hydrocarbons obtained from the step s); and

[0144] • the oxygenate fraction comprising water obtained from the step s).

[0145] In an embodiment, all glycerol and water obtained at the step h), is directed to the step r).

[0146] In an embodiment, the light hydrocarbons obtained at the step he) and directed to the step r) comprise C1 - C7 hydrocarbons, preferably C1 - C4 hydrocarbons, more preferably C1 - C3 hydrocarbons, even more preferably C1 - C2 hydrocarbons, most preferably C1 hydrocarbons. According to an embodiment, further feed to the reforming step r) comprises oxygenates comprising mainly water, being obtained from step he). According to an embodiment, further feed to the reforming step r) comprises carbon oxide(s) obtained also from step he).

[0147] When fed to reforming r) unit, the FT-process light gases obtained from the step s) will enhance the production of hydrogen. In an embodiment, the light hydrocarbons obtained at the step s) and directed to the step r) comprise C1 - C4 hydrocarbons, preferably C1 - C2 hydrocarbons, most preferably C1 hydrocarbons.

[0148] In an embodiment, water and other oxygenates are formed as a side or co-product in the step s). For example, when the synthesis is conducted as a FT synthesis and light oxygenates may be recovered as a side or co-product and recycled to reforming in step r). In an embodiment, the oxygenates obtained at the step he), and directed to the step r), comprise mainly water. In an embodiment, the oxygenate fraction comprising water from the step s) is directed to reforming, such as steam reforming, step r), to be reformed into CO in the reforming unit. This is advantageous, as this will reduce the issues of wastewater treatment. In a further embodiment, carbon monoxide may be obtained from the synthesis step s) and directed to the reforming step r). In an embodiment, the process further comprises feeding additional synthesis gas mixture to the hydrocarbon synthesis at the step s). In an embodiment, the composition of the additional synthesis gas mixture fed into the hydrocarbon synthesis step s) is adjusted to the selected synthesis process.

[0149] The hydrocarbon intermediate B recovered from the hydrocarbon synthesis reaction effluent from the step s) comprises carbon numbers typically from C8 to C16. Said hydrocarbons of the hydrocarbon intermediate B comprise predominantly C8 to C16 n-paraffins. According to an embodiment, the hydrocarbon intermediate B comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-% of C8 to C16 n-paraffins, of the total weight of the hydrocarbon intermediate B. As minor components, the hydrocarbon intermediate B may contain some olefins, oxygenates and / or C17+ paraffins. The hydrocarbon intermediate B obtained from the hydrocarbon synthesis step s) comprises hydrocarbons suitable for SAF component, preferably the hydrocarbon intermediate B has a broad hydrocarbon distribution, which contributes to the beneficial properties of the SAF component. When eventually isomerized, such hydrocarbon intermediate provides an advantageous sustainable aviation fuel component composition.

[0150] In an embodiment, the step s) comprises Fischer-Tropsch process, and the light fraction comprising C1 - C4 hydrocarbons, naphtha fraction, heavy hydrocarbon fraction and the oxygenate fraction are recovered as further fractions in addition to the hydrocarbon intermediate B.

[0151] The process also comprises step i) comprising isomerizing the hydrocarbon intermediate A from step he) and the hydrocarbon intermediate B from step s), to obtain at least a SAF component comprising C9 - C17 hydrocarbons.

[0152] The obtained SAF component can be used as sustainable aviation fuel (SAF) alone or as its component.

[0153] In the overall process the sub-processes A and B have been integrated to share at least the isomerization step i). As used herein, isomerizing (I) refers to reactions where long chain n- paraffins are isomerized to long chain isoparaffins. In the paraffin (I) reaction, the number of carbon atoms does not change. Said step i) comprises isomerizing the hydrocarbon intermediate A from step he) and the hydrocarbon intermediate B from step s) to obtain a SAF component comprising C9 - C17 hydrocarbons. As minor components, the SAF component can contain also some C8 and C17 hydrocarbons. In an embodiment, the process comprises the step i) subjecting the hydrocarbon intermediate A from the step he) and the hydrocarbon intermediate B from the step s) to isomerization, to obtain at least a SAF component comprising C9 -C17 hydrocarbons. In an embodiment, the hydrocarbon intermediate A from the step he) and the hydrocarbon intermediate B from the step s) are isomerized directly, without any intermediate processing steps, after said steps he) and s).

[0154] In addition to the main product, the SAF component comprising C9 - C17 hydrocarbons, at least one further hydrocarbon fraction selected from naphtha fraction comprising isomerized C5 - C7 hydrocarbons and isomerized heavy hydrocarbon fraction comprising isomerized C18+ hydrocarbons, is recovered from step i). Both further products are of high value, the recovery of which improves the overall yield from the renewable feedstock and enables fractionation of the isomerization effluent with desired optimization.

[0155] In an embodiment, in the isomerization step i), the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from step s) and the hydrocarbon intermediate A from step he) are combined and isomerized together.

[0156] Combined isomerizing is especially favored when both the hydrocarbon intermediate A and hydrocarbon intermediate B are relatively similar to one another in their chemical composition. Advantages are then related to economics of scale.

[0157] In an embodiment, in the step i) the hydrocarbon intermediate A and the hydrocarbon intermediate B are combined in a ratio of 1-10:1. In an embodiment, the ratio of hydrocarbon intermediate A to hydrocarbon intermediate B, i.e. , the ratio A:B, when combined in the isomerization step i), is 1 - 10:1 , respectively.

[0158] In an embodiment, the ratio A:B at the isomerization step i) is 1 :1 , preferably 2:1 , more preferably 3:1 , more preferably 4:1 , more preferably 5:1 , more preferably 6:1 , more preferably 7:1 , more preferably 8:1 , even more preferably 9:1 , most preferably 10:1. Such combination ratios of hydrocarbon intermediate A and the hydrocarbon intermediate B are beneficial, as the obtained SAF component has a broad carbon number distribution, contributing, for example, to good thermal properties of the SAF component. Further, such combination ratios of hydrocarbon intermediate A and the hydrocarbon intermediate B are beneficial, as the amount of cyclic (naphthenic and aromatic) compounds which have beneficial impact to SAF component properties (e.g. cold viscosity), can be selectively adjusted in the SAF component.

[0159] According to an embodiment, in the isomerization step i), the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from the step s) and the hydrocarbon intermediate A from step he) are isomerized separately. Nevertheless, in the case of separate isomerization of the hydrocarbon intermediate A and B, the isomerization takes please in the same isomerization unit(s). Separate isomerization enables specific adjusting of the reaction conditions to provide best conversion and selectivity into the SAF component comprising C9 - C17 hydrocarbons. For example, if one of the intermediates comprises a significant amount of heavy hydrocarbons or in case heavy hydrocarbons recovered from other parts of the process or even recycled from the effluent of the isomerizing itself, are fed to step i), isomerizing reaction conditions allowing mild hydrocracking in addition to isomerization reactions serve the end purpose of good SAF component yield and quality. Further, in some embodiments, a separate isomerizing of hydrocarbon intermediate B and hydrocarbon intermediate A could be feasible timewise.

[0160] In an embodiment, the process comprises combining the isomerized hydrocarbon intermediate A and the isomerized hydrocarbon intermediate B, thereby obtaining the SAF component comprising C9 - C17 hydrocarbons. In an embodiment, both, the isomerized hydrocarbon intermediate A and the isomerized hydrocarbon intermediate B alone would fulfill the requirements set for the SAF component. In an embodiment, both, the combined isomerized hydrocarbon intermediate A and the isomerized hydrocarbon intermediate B fulfill the requirements set for the SAF component. In an embodiment, the process comprises step i) isomerizing the hydrocarbon intermediate A from step he) and the hydrocarbon intermediate B from step s), thereby obtaining the SAF component comprising C9 - C17 hydrocarbons.

[0161] The isomerization treatment of the hydrocarbon intermediate A or the hydrocarbon intermediate B converts at least part of n-paraffins to i-paraffins, especially to mono-branched i-paraffins. By (further) raising the isomerization degree, for example by increasing severity of the isomerization, more n-paraffins can be converted to i-paraffins, and mono-branched i-paraffins to multiple- branched i-paraffins, such as di-branched, tri-branched i-paraffins, even i-paraffins comprising more than three branches. A catalytic hydroisomerization is preferred.

[0162] In an embodiment, the present process further comprises feeding additional hydrogen to the isomerization at the step i). In an embodiment, the isomerization step i) comprises hydroisomerization. The hydroisomerization treatment is preferably conducted at a temperature within a range from 200 °C to 500 °C, preferably from 230 °C to 500 °C, more preferably from 250 °C to 450 °C, even more preferably from 280 °C to 370 °C, a pressure within a range from 1 MPa to 10 MPa , preferably from 2 MPa to 8 MPa or from 3 MPa to 10 MPa , a H2 partial pressure within a range from 1 MPa to 10 MPa , preferably from 2 MPa to 8 MPa, a weight hourly space velocity within a range from 0.1 to 10, preferably from 0.2 to 8, more preferably from 0.4 to 6 kg n-paraffinic hydrocarbon feed per kg catalyst per hour, and a H2 to n-paraffinic hydrocarbon feed ratio within a range from 10 to 2000, preferably from 50 to 1000 normal liters H2 per liter n- paraffinic hydrocarbon feed.

[0163] Severity of the isomerization may be increased by at least one or more of: decreasing WHSV, increasing temperature, and / or increasing pressure. The isomerization treatment may be performed in the presence of known isomerization catalysts, for example, catalysts containing a molecular sieve, and / or a metal selected from Group VIII of the Periodic Table, and a carrier. Preferably, the isomerization catalyst is a catalyst containing SAPO-11 or SAPO-41 or ZSM-22 or ZSM-23 or ferrierite, and Pt or Pd or Ni, and AI2O3 or SiO2. Typical isomerization catalysts are, for example, Pt / SAPO-11 / AI2O3, Pt / ZSM-22 / AI2O3, Pt / ZSM-23 / AI2O3, and / or Pt / SAPO-11 / SiO2. The isomerization may be conducted for example as described in prior art publications, such as FI100248B, EP1741768A1 , EP2155838B1 , FI129220B, FI130345B or FI130344B.

[0164] In some embodiments the isomerization step i) conditions are selected to allow mild hydrocracking. In hydrocracking, the fatty acid molecules will split to hydrocarbons that have lower carbon number compared to fatty acid in the presence of hydrogen and a catalyst. Depending on the choice of the catalyst, the hydrocarbon distribution can be adjusted. Besides hydrocarbons, water and carbon oxides are formed. Typical hydrocracking catalysts are sulfurized NiMo / NiW or noble metal on zeolite based catalysts on acid support. The hydrogen pressure is typically above 5 MPa and reaction temperatures are above 350 °C. With the selection of reaction conditions and catalyst properties, hydrocracking reactions can be enhanced and the distribution of hydrocarbons to broaden carbon number range is achieved. Further, hydrocracking of fatty acids forms cyclic (naphthenic and aromatic) compounds that have beneficial impact to SAF properties.

[0165] The main product recovered from the isomerization effluent is a sustainable aviation fuel or fuel component(s) for sustainable aviation fuel (SAF). The sustainable aviation fuel or fuel component(s) thereto may be separated from the isomerization effluent as a fraction. In an embodiment, the SAF component is the fraction comprising renewable C9-C17 hydrocarbons, such as branched C9-C17 hydrocarbons which are suitable for use in aviation fuel applications, such as jet fuel or components thereto. The aromatic compounds comprised in the hydrocarbon intermediate A are efficiently hydrogenated during the isomerization i) process into naphthenic compounds that have beneficial impact to SAF properties, although traces of aromatics may remain in the final SAF component. In an embodiment, the SAF component comprises 0.5 wt-% or less, 0.1 wt-% or less, or 0.01 wt-% or less of aromatic compounds. Hence, according to an embodiment, the amount of cycloparaffins in the SAF component varies from 1.0 to 5.0 wt-%, preferably from 1.8 to 3.1 wt-%.

[0166] The SAF component may be separated from the isomerization effluent as a fraction having a T5 temperature (5 vol-% recovered) within a range from 170 to 280 °C, preferably within a range from 220 to 260 °C, and a T95 temperature within a range from 250 to 340 °C, preferably within a range from 270 to 320 °C, according to EN ISO 3405-2019, and preferably a difference between T5 and T95 temperatures within a range from 40 to 100 °C. In an embodiment, the SAF component obtained with the present process fulfils the required product properties of ASTM D7566-2022 Annex A2.

[0167] The sustainable aviation fuel or fuel component(s) for sustainable aviation fuel may be defined as a fraction comprising renewable C9 - C17 hydrocarbons, preferably mainly C10-C16, hydrocarbons, such as branched C9 - C17 hydrocarbons which are suitable for use in aviation fuel applications, such as jet fuel or components thereto. The separated hydrocarbon fraction has preferably an initial boiling point at atmospheric pressure of at least 150 °C and a final boiling point of up to 290 °C.

[0168] As additional product(s), further fuel(s) or fuel components and / or renewable chemical(s) may be recovered from the present process, from the hydrocracking step he), from the isomerization step i), and / or from the synthesis step s).

[0169] From the hydrocarbon synthesis step s) different renewable chemicals may be recovered depending on the specific synthesis process selected. In case the synthesis is conducted as a FT-process, a fraction of C5 - C7 n-paraffins may be recovered as a product suitable as renewable naphtha from the step s).

[0170] Further products may be recovered from the step i) likewise. In an embodiment, at least one further hydrocarbon fraction selected from isomerized naphtha fraction comprising C5 - C7 hydrocarbons, and isomerized heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons, is recovered from the step i).

[0171] From the isomerization step i) and product separation thereof, in addition to the sustainable aviation fuel or fuel component(s) for SAF further products recovered may thus comprise renewable naphtha, renewable (winter) diesel and / or another product comprising isomerized heavy hydrocarbons, such as hydrocarbons having the carbon number above C18 (i.e. C18+ isomerized hydrocarbons). The heavy hydrocarbons can optionally be separately upgraded.

[0172] In an embodiment, at least three streams from the sub-process A and B are exchanged between said sub-processes. This contributes significantly to the integration of the sub-process A and B. In an embodiment, the processes A and B are integrated through at least three streams comprising hydrocarbons and / or oxygenates. In an embodiment, the at least three streams exchanged between processes A and B comprise: 1) the glycerol comprised by the aqueous phase obtained from the step h) and provided to the step r); 2) light hydrocarbons and oxygenates obtained from the step he) and provided to the step r); and 3) heavy hydrocarbons (comprising C17+ hydrocarbons) obtained from the step s) and provided to the hydrocracking of the step he).

[0173] In addition to the mass flow integration of different streams as defined herein, the overall process may further comprise energy integration wherein energy recovered from exothermic reactions is used for endothermic reactions. Requirement for external energy is thereby decreased. Accordingly, in an embodiment, thermal energy recovered from the step s) is utilized in at least one of the steps selected from hydrocracking in the step he), reforming in the step r), carbon refining in the step c), and isomerizing in the step i).

[0174] In the current process, water can be recovered and recycled in gaseous phase as steam between different process steps. In an embodiment, H2O obtained in at least one of the steps c) and s) is recycled to reforming in the step r) and / or to hydrolysis in the step h). In an embodiment, water obtained in at least one of the steps c) and s) is recycled to reforming in the step r) and / or to hydrolysis in the step h).

[0175] In an embodiment, with H2O is meant water.

[0176] The process steps c) and s) provide H2O in gaseous phase, as steam, which may be fed to processes where water is needed in the stoichiometry of the reaction and / or where the energy of the steam advances the reaction. Savings in H2O vaporization / steam production provide a considerable advantage. As used herein, water vapor and H2O vapor refer to water vapor in gaseous phase and in sufficient purity for the reactions where it is used. For example, the synthesis processes as discussed herein, the FT process, the isosynthesis process and the methanol synthesis and upgrading process, release H2O from reaction thereof as very pure water vapor, which is excellent for use in e.g. reforming in the sub-process B and / or hydrolysis in the sub-process A.

[0177] Example embodiments are next discussed with reference to appended figures presenting schematic outline of the overall process. In figure 1 , the unit operations and units therefore are referred to corresponding to the steps of the claim 1 . In said figure 1 , sub-process A runs from left to right through steps h) and he). Correspondingly, sub-process B runs from left to right through steps r), c) and s). The final step i), isomerization, integrates said sub-processes producing a SAF component comprising C9 - C17 hydrocarbons as the main product.

[0178] The compositions of streams corresponding to the numbers used in said figures are as defined in the following table 2.

[0179] Table 2. Stream compositions In the beginning of the sub-process A, a renewable feedstock 10 mainly comprising triglycerides is fed to the hydrolysis unit h) with water 110. The renewable feedstock 10 may also comprise some naphthenic acids as a minor component. From the hydrolysis unit h), the effluent comprising fatty acids, water and glycerol as the reaction products is subjected to liquid / liquid separation. Suitable separation methods are known in the art. After the separation, the oil phase 20 mainly comprising fatty acids, but optionally also some naphthenic acids as a minor component, is obtained. Furthermore, the aqueous stream, i.e. , the aqueous phase 30 comprising glycerol and water vapor is also obtained from the separation.

[0180] The oil phase 20 is then subjected to hydrocracking he) process of the sub-process A. Further to the oil phase 20, additional hydrogen 220 is also fed into the hydrocracking he) process. The main product (in terms of quantity) obtained from the hydrocracking he) process is a stream comprising linear and branched hydrocarbons, preferably comprising predominantly n-paraffins having carbon number from C8 to C16, isoparaffins, and cycloalkanes. Some C17 - C18 hydrocarbons can be obtained from the hydrocracking he) process as a minor component as well. Together said minor and main components make up the hydrocarbon intermediate A stream 40, which is directed to a hydroisomerization i) process unit.

[0181] Moreover, light C1 - C7 hydrocarbons and oxygenates are also obtained from the hydrocracking he) process. At this stage, at least part of the light hydrocarbons with carbon number C5 - C7 can be recovered from the step he) as a stream 55, to be utilized as a renewable naphtha component. Any remaining light hydrocarbons having carbon number C1 - C4 can be utilized in reforming, such as steam reforming, step r) of the sub-process B. Thus, a further stream comprising mainly H2O vapor and in minor quantities of C1 - C4 hydrocarbons, carbon oxides CO2 and CO, methanol and acetone, are obtained as a stream 50 from the hydrocracking he) process. The stream 50 is directed to the reforming step r), which is the first step of the sub-process B.

[0182] Furthermore, the aqueous phase 30 obtained from the liquid / liquid separation as part of the hydrolysis h), is subjected to the same reforming process r). The main feed to the reforming r) is the aqueous phase 30 comprising glycerol, obtained from hydrolysis unit h). A further feed entering the reforming step r) comprise a recycle stream 810 comprising light hydrocarbons, mainly C1 - C4 paraffinic hydrocarbons, from the synthesis unit s). Yet further, additional feed(s) to the reforming r) may be provided. Optionally additional glycerol and water may be provided in a stream 350 to the reforming r).

[0183] From the reforming unit r), a gaseous reforming effluent stream 60 comprising H2, CO, CO2, and H2O is fed to carbon refining c). The effluent stream 60 is subjected to carbon refining in unit c) in order to adjust H2 / CO ratio to be suitable for the hydrocarbon synthesis as the next step s). Depending on the choice of the carbon refining method and unit c) therefore, also further H2 may be fed thereto.

[0184] As the last step of the sub-process B, the gas stream 70, comprising mainly CO and H2, but also smaller quantities of CO2, is subjected to synthesis conditions in hydrocarbon synthesis unit s). Additional H2 and CO can be supplied to the hydrocarbon synthesis s) within the stream 75. The hydrocarbon end product from the synthesis s) is fractionated, and the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons is recovered as a major component from the fractionation.

[0185] Further fractions recovered from the hydrocarbon synthesis step s) may comprise C1 - C4 paraffinic hydrocarbons, which are directed to the reforming unit as part of a stream 810. Moreover, gaseous H2O removed from hydrocarbon synthesis s) unit via a stream 820 can be directed to the reforming unit r) or alternatively / in addition fed to hydrolysis unit h) where the gaseous H2O contributes to the energy efficiency.

[0186] Any heavy C17+ hydrocarbons resulting from the synthesis step s) are preferably directed to the hydrocracking unit he) of the sub-process A in a stream 85, to be converted into lower molecular weight compounds suitable for the SAF component. Depending on the specific hydrocarbon synthesis applied at the step s), C17+ hydrocarbons can alternatively or additionally be recovered as a minor component as part of the hydrocarbon intermediate B 80, to be directed to hydroisomerization i). For example, when the synthesis is a FT-process, C17+ hydrocarbons can be obtained and provided as part of the hydrocarbon intermediate B 80 to the hydroisomerization i).

[0187] According to an embodiment, a fraction comprising C5 - C7 hydrocarbons, preferably C5-C7 n- paraffins are also recovered as a side product from synthesis unit s) via a stream 830. Such fraction is usable as a renewable naphtha component.

[0188] The hydrocarbon intermediate A 40 stream and the hydrocarbon intermediate B 80 stream are both directed to a hydroisomerization i) unit, together with additional hydrogen stream 440. The hydroisomerization i) converts linear hydrocarbons to i-paraffins. From the effluent of the hydroisomerization, a SAF component 90 comprising isomerized C8-C16 isoparaffins is recovered as the main major component. The SAF component 90 further comprises as a minor component C8 - C16 cyclic hydrocarbons, contributing to the improved SAF component 90 qualities. Further possible products obtained from the hydroisomerization i) comprise naphtha fraction 910 comprising paraffins, predominantly i-paraffins within carbon number range from C5 to C7, and to lesser extent C5 - C7 cyclic hydrocarbons. Yet further possible product obtained from the hydroisomerization i), is an isomerized heavy hydrocarbon fraction (not shown) comprising paraffins, predominantly i-paraffins within carbon number range from C18 to C22. Such fraction is usable as a renewable diesel component. Various embodiments have been presented. It should be appreciated that in this document, words comprise, include, and contain are each used as open-ended expressions with no intended exclusivity.

[0189] The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention. Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Claims

CLAIMS1 . A process for producing fuel components for sustainable aviation fuel (SAF) from a renewable feedstock comprising triglycerides, wherein the process comprises:- a sub-process A for converting the renewable feedstock to a hydrocarbon intermediate A, comprising: h) subjecting the renewable feedstock to hydrolysis in the presence of water to produce glycerol, water and fatty acids, thereby obtaining an oil phase and an aqueous phase; he) subjecting the oil phase comprising fatty acids obtained in the hydrolysis at the step h) to hydrocracking, to obtain the hydrocarbon intermediate A suitable for isomerization, and hydrocracking by-products, such as light hydrocarbons and oxygenates;- a sub-process B for converting products obtained from the sub-process A to a hydrocarbon intermediate B, comprising: r) reforming the glycerol obtained from the aqueous phase from the step h) and light hydrocarbons and oxygenates obtained from the step he), into a gas mixture comprising carbon oxide(s) and hydrogen; c) subjecting the gas mixture comprising carbon oxide(s) and hydrogen from step r) to carbon refining, to obtain a gas mixture comprising carbon monoxide and hydrogen gas; and s) subjecting the gas mixture comprising the carbon monoxide and hydrogen gas to hydrocarbon synthesis step selected from a Fischer-Tropsch process, isosynthesis process or methanol synthesis and upgrading process, and recovering the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from the hydrocarbon synthesis effluent; and- step i) comprising isomerizing the hydrocarbon intermediate A from step he) and the hydrocarbon intermediate B from step s), to obtain at least a SAF component comprising C9 - C17 hydrocarbons.

2. The process according to claim 1 , wherein the light hydrocarbons obtained at the step he) comprise C1 - C7 hydrocarbons, and the oxygenates obtained at the step he) comprise one or more of water, light alcohols, ketones and aldehydes.

3. The process according to claim 1 or 2, wherein the hydrocarbon intermediate A comprises paraffins suitable for isomerization and / or cyclic hydrocarbons, such as naphthenic and aromatic hydrocarbons.

4. The process according to any of the preceding claims, wherein the carbon refining of the step c) comprises adjusting a hydrogen / carbon monoxide ratio of the gas mixture obtained from the step r), preferably said adjusting is carried out by water gas shift (WGS) reaction.

5. The process according to any of the preceding claims, wherein at least one further fraction is recovered from the step s), the at least one further fraction being selected from:• a naphtha fraction comprising C5 - C7 hydrocarbons,• a heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons,• a light fraction comprising C1 - C4 hydrocarbons,• an oxygenate fraction comprising water, and• combinations thereof.

6. The process according to claim 5, wherein at least part of the heavy hydrocarbon fraction recovered from the step s) is directed to hydrocracking of the step he).

7. The process according to claim 5 or 6, wherein at least part of the oxygenate fraction comprising water, recovered from the step s), is directed to reforming of the step r).

8. The process according to any of the preceding claims 5-7, wherein the step r) comprises feeding in the reforming one or more of:• glycerol and water obtained at the step h),• the light hydrocarbons obtained at the step he);• the oxygenates obtained at the step he);• the light fraction comprising C1 - C4 hydrocarbons obtained from the step s); and• the oxygenate fraction comprising water obtained from the step s).

9. The process according to any of the preceding claims, further comprising feeding additional synthesis gas mixture to the hydrocarbon synthesis at the step s).

10. The process according to any of the preceding claims, wherein in the isomerization step i), the hydrocarbon intermediate B comprising C8 - C16 hydrocarbons from the step s) and the hydrocarbon intermediate A from the step he) are combined and isomerized together.

11. The process according to any of the preceding claims, wherein the step i) the hydrocarbon intermediate A and the hydrocarbon intermediate B are combined in a ratio of 1-10:1.

12. The process according to any of the preceding claims, wherein at least one further hydrocarbon fraction selected from isomerized naphtha fraction comprising C5 - C7 hydrocarbons, and isomerized heavy hydrocarbon fraction comprising C17+ carbon number hydrocarbons, is recovered from step i).

13. The process according to any of the preceding claims, wherein at least three streams from the sub-process A and B are exchanged between said sub-processes.

14. The process according to any of preceding claims, wherein thermal energy recovered from the step s) is utilized in at least one of the steps selected from hydrocracking in the step he), reforming in the step r), carbon refining in the step c), and isomerizing in the step i).

15. The process according to any of preceding claims, wherein water obtained in at least one of the steps c) and s) is recycled to reforming in the step r) and / or to hydrolysis in the step h).

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