TECHNICAL FIELD

The present disclosure generally relates to a process for producing renewable fuel components. The disclosure relates particularly, though not exclusively, to a process for producing at least one or more liquid transportation fuel components, preferably at least an aviation fuel component.

BACKGROUND

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

There is an ongoing need to reduce greenhouse gas emissions and/or carbon footprint in transportation, especially aviation. Accordingly, interest towards renewable aviation fuels and aviation fuel components is and has been growing.

Processes for producing aviation fuel components from renewable raw materials have been proposed. However, the yield of aviation fuel components (compared to other fuel components) has been relatively low in said processes. Also, there is a need to improve quality of renewable aviation fuel components. Particularly, there is an interest towards producing aviation fuel components that could be used in aviation fuels in elevated amounts, or when suitably additized even as such as an aviation fuel.

SUMMARY

It is an aim to solve or alleviate at least some of the problems related to prior art. An aim is to improve quality of aviation fuel components obtainable from renewable sources. A further aim is to enable increasing the yield of an aviation fuel component. Another aim is to reduce formation of C1-C4 hydrocarbons, especially C1-C2 hydrocarbons, in a process for producing renewable liquid transportation fuel components. Yet further, an aim is to prolong hydroisomerisation catalyst lifetime in a process for producing renewable liquid transportation fuel components.

The appended claims define the scope of protection. Any examples and technical descriptions of apparatuses, systems, products and/or methods in the description and/or drawings not covered by the claims are presented as examples useful for understanding the invention. According to a first example aspect, there is provided a process for producing at least one liquid transportation fuel component, the process comprising: providing a paraffinic hydrocarbon feed comprising at least 60 wt-% paraffins of the total weight of the paraffinic hydrocarbon feed, of which paraffins at least 5 wt-% are isoparaffins; subjecting a first reaction section feed comprising the paraffinic hydrocarbon feed, and optionally a recycle stream and/or a side cut, to hydrocracking in a first reaction section in the presence of a hydrocracking catalyst to obtain a hydrocracking effluent; subjecting a second reaction section feed comprising the hydrocracking effluent to hydroisomerisation in a second reaction section in the presence of a hydroisomerisation catalyst to obtain a hydroisomerisation effluent; and feeding the hydroisomerisation effluent to a fractionation and recovering from the fractionation at least one or more liquid transportation fuel components, and optionally the recycle stream and/or the side cut.

The present process enables obtaining improved yield and/or quality of the recovered fuel component(s), and particularly of a preferably recovered aviation fuel component, while the amount of low-profit products (fuel gas) may be kept at a low level. In the present process, subjecting the first reaction section feed comprising the isoparaffin-containing paraffinic hydrocarbon feed to hydrocracking, and thereafter to hydroisomerisation (HI), followed by fractionation, has proven successful in converting the paraffinic hydrocarbon feed into high quality liquid fuel components having excellent cold properties, with very high combined yield of an aviation fuel component and a diesel fuel component. The ratio of these components may be easily adjusted in the present process for example by recovering from the fraction a recycle stream and/or a side cut, and incorporating the recycle stream and/or the side cut into the first reaction section feed to increase the content of heavier hydrocarbons and/or highly isomerised paraffins therein.

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.

BRIEF DESCRIPTION OF THE FIGURES

Some example embodiments will be described with reference to the accompanying figures, in which: Fig. 1 illustrates schematically an example embodiment of the present process involving hydrocracking, for producing at least one or more liquid transportation fuel components.

Fig. 2 illustrates schematically another example embodiment of the present process involving hydrocracking, for producing at least one or more liquid transportation fuel components.

Fig. 3 presents distillation curves for degassed effluents (liquid products) from one test run according to an example embodiment of the present process and from three comparative test runs, as presented in Example 1.

Fig. 4 illustrates schematically a process involving hydrocracking, for producing at least one or more liquid transportation fuel components.

Fig. 5 illustrates schematically another process involving hydrocracking, for producing at least one or more liquid transportation fuel components.

DETAILED DESCRIPTION

In the following description, like reference signs denote like elements or steps.

All standards referred to herein are the latest revisions available at the filing date, unless otherwise mentioned.

Unless otherwise stated, regarding distillation characteristics, such as initial boiling points (IBP), final boiling points (FBP), T5 temperature (5 vol-% recovered), T95 temperature (95 vol-% recovered), and boiling ranges, reference is made to EN ISO 3405-2019. IBP is the temperature at the instant the first drop of condensate falls from the lower end of the condenser tube, and FBP is the maximum thermometer reading obtained during the test, usually occurring after the evaporation of all liquid from the bottom of the flask. For boiling point distribution reference may also be made to GC-based method (simdis) ASTM D2887- 19e1 , or for gasoline range hydrocarbons to ASTM D7096-19.

As used in the context of this disclosure, aviation fuel composition refers to hydrocarbon components suitable for use in fuel compositions meeting standard specifications for aviation fuels, such as specifications laid down in ASTM D7566-21. Typically, such aviation fuel components boil, i.e. have IBP and FBP, within a range from about 100 °C to about 300 °C, such as within a range from about 150 °C to about 300 °C, as determined according to EN ISO 3405-2019.

As used in the context of this disclosure, diesel fuel component refers to hydrocarbon compositions suitable for use in fuel compositions meeting standard specifications for diesel fuels, such as specifications laid down in EN 590:2022 or in EN 15940:2016 + A1:2018 + AC:2019. Typically, such diesel fuel components boil, i.e. have IBP and EBP, within a range from about 160 °C to about 380 °C, as determined according to EN ISO 3405-2019.

As used in the context of this disclosure, gasoline fuel component or naphtha refers to hydrocarbon components suitable for use in fuel compositions meeting standard specifications for gasoline fuels, such as specifications laid down in EN 228-2012 + A1- 2017. Typically, such gasoline fuel components boil, i.e. have IBP and EBP, within a range from about 25 °C to about 210 °C, as determined according to EN ISO 3405-2019.

As used in the context of this disclosure, marine fuel component refers to hydrocarbon components suitable for use in fuel compositions meeting standard specifications for marine fuels, such as specifications laid down in ISO 8217-2017. Typically, such marine fuel components boil, i.e. have IBP and EBP, within a range from about 180 °C to about 600 °C, such as from about 180 °C to about 400 °C as determined according to EN ISO 3405-2019.

As used herein hydrocarbons refer to compounds consisting of carbon and hydrogen. Hydrocarbons of particular interest in the present context comprise paraffins, n-paraffins, i- paraffins, monobranched i-paraffins, multiple-branched i-paraffins, olefins, naphthenes, and aromatics. Oxygenated hydrocarbons refer herein to hydrocarbons comprising covalently bound oxygen.

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 i-paraffins.

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

As used herein, cyclic hydrocarbons refer to all hydrocarbons containing cyclic structure(s), including cyclic olefins, naphthenes, and aromatics. Naphthenes refer herein to cycloalkanes 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. Aromatics 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.

In the context of the present disclosure, for compositions boiling at 36 °C or higher (at standard atmospheric pressure), contents of n-paraffins, i-paraffins, monobranched i- paraffins, various multiple-branched isoparaffins, naphthenes, and aromatics, are expressed as weight % (wt-%) relative to the degassed weight of the feed, stream, effluent, product, component, or sample in question or, when so defined, as weight-% (wt-%) relative to the (total) weight of paraffins or (total) weight of i-paraffins of the feed, stream, effluent, product, component, or sample in question. Said contents may be determined by GCxGC- FID/GCxGC-MS method, preferably conducted as follows: GCxGC (2D GO) method was run as generally disclosed in UOP 990-2011 and by Nousiainen M. in the experimental section of his Master's Thesis Comprehensive two-dimensional gas chromatography with mass spectrometric and flame ionization detectors in petroleum chemistry, University of Helsinki, August 2017, with the following modifications. The GCxGC was run in reverse mode, using a semipolar column (Rxi17Sil) first and a non-polar column (RxiSSil) thereafter, followed by FID detector, using run parameters: carrier gas helium 31.7 cm/sec (column flow at 40 °C 1.60 ml/min); split ratio 1 :350; injector 280 °C; Column T program 40 °C (0 min) - 5 °C/min - 250 °C (0 min) - 10 °C/min - 300 °C (5 min), run time 52 min; modulation period 10 sec; detector 300 °C with H240 ml/min and air 400 ml/min; makeup flow helium 30 ml/min; sampling rate 250 Hz and injection size 0.2 microliters. Individual compounds were identified using GCxGC-MS, with MS-parameters: ion source 230 °C; interface 300 °C; scan range 25 - 500 amu; event time (sec) 0.05; scan speed 20000. Commercial tools (Shimadzu's LabSolutions, Zoex's GC Image) were used for data processing including identification of the detected compounds or hydrocarbon groups, and for determining their mass concentrations by application of response factors relative to n-heptane to the volumes of detected peaks followed by normalization to 100 wt-%. Olefins were lumped with naphthenes and heteroatomic species with aromatics, unless separately reported. The limit of quantitation for individual compounds of this method is 0.1 wt-%.

In the context of the present disdosure, various characteristics of the feeds, streams, effluents, products, components, or samples are determined according to the standard methods referred to or disclosed herein, as properly prepared. For example, cloud point is determined according to ASTM D 5771-17 from a degassed feed, stream, effluent, product, component, or sample.

Typically, the various paraffinic feeds, streams, effluents, and fuel components as recovered products or fractions thereof, referred to herein, may comprise in addition to hydrocarbons, also varying trace amounts of e.g. heteroatom-containing hydrocarbons and inorganic compounds as impurities, and the oxygenated hydrocarbon feed varying amounts of e.g. other heteroatom-containing hydrocarbons and inorganic compounds as impurities. Generally, the level of impurities in the main process streams is highest in the first parts of the process and decreases subsequently being negligible or even below detection limit in the recovered liquid transportation fuel component(s).

In the context of this disclosure, feed(s) to reaction sections, particularly to the first reaction section and/or the second reaction section, are defined so that H2 possibly fed to the respective reaction section, for example H2 fed to the hydrocracking and/or H2 fed to the hydroisomerisation, is excluded from the definition of the feed(s).

As used herein, hydrocracking (HC) effluent refers to total HC effluent or degassed HC effluent, as the case may be, and the term HC effluent may encompass both of these.

In the context of this disclosure, CX+ paraffins, CX+ n-paraffins, CX+ i-paraffins, CX+ monobranched i-paraffins, CX+ multiple-branched i-paraffins, CX+ hydrocarbons, or CX+ fatty adds refer to paraffins, n-paraffins, i-paraffins, mono-branched i-paraffins, multiple- branched i-paraffins, hydrocarbons, or fatty acids, respectively, having a carbon number of at least X, where X is any feasible integer. It is understood that every compound falling within the definition is not necessarily present.

In the context of this disclosure, CY- paraffins, CY- n-paraffins, CY- i-paraffins, CY- monobranched i-paraffins, CY- multiple-branched i-paraffins, CY- hydrocarbons, or CY- fatty adds refer to paraffins, n-paraffins, i-paraffins, mono-branched i-paraffins, multiple- branched i-paraffins, hydrocarbons, or fatty acids, respectively, having a carbon number of at most Y, wherein Y is any feasible integer. It is understood that every compound falling within the definition is not necessarily present. In the context of this disclosure, CXy-CXz (or from CXy to CXz) paraffins, CXy-CXz n- paraffins, CXy-CXz i-paraffins, CXy-CXz mono-branched i-paraffins, or CXy-CXz multiple- branched i-paraffins, CXy-CXz hydrocarbons, or CXy-CXz fatty adds refer to a range of paraffins, n-paraffins, i-paraffins, mono-branched i-paraffins, or multiple-branched i- paraffins, hydrocarbons, or fatty acids, respectively, where Xy and Xz are feasible end-value integers, wherein the carbon numbers within such range is as indicated by the end-value integers and any integers between said end-values, if present. However, paraffins, n- paraffins, i-paraffins, mono-branched i-paraffins, multiple-branched i-paraffins, hydrocarbons, or fatty acids, as the case may be, of all said carbon numbers within said range, particularly at or around the end points are not necessarily present, except when so expressly indicated. On the other hand, isomers, by definition, may comprise several hydrocarbons compounds having the same carbon number, such as C15 isomers may comprise methyltetradecanes (different position of the methyl-branch), dimethyltridecanes (different positions of the two methyl-branches), etc, wherein “C15 isomers" comprises the sum amount of all such variants.

Typically, a sum amount as of weight or volume of paraffins, n-paraffins, i-paraffins, monobranched i-paraffins, multiple-branched i-paraffins, hydrocarbons, or fatty acids, as defined each time, paraffins of all carbon numbers included is meant. For example, C15 to C22 n- paraffins refers to any n-paraffins within said range if present, such as C15, C16, C17, C18, C19, C20, C21, and C22 n-paraffins, even if the content of C15 n-paraffins was zero. In other words, a sum amount is obtainable by addition of 0 (referring to absent C15 n- paraffins) to the sum weight of all other C15 to C22 n-paraffins present.

Isomerisation converts at least a certain amount of n-paraffins to i-paraffins, especially to mono-branched i-paraffins. By (further) raising the isomerisation degree, for example by increasing severity of the hydroisomerisation as described hereinafter, more n-paraffins can be converted to i-paraffins, and mono-branched i-paraffins can be converted to multiple- branched i-paraffins, such as di-branched, tri-branched i-paraffins, even i-paraffins comprising more than three branches.

As used herein and in the context of the first reaction section, degree of effective cracking refers to cracking that yields non-gaseous (NTP) cracking products, and especially as expressed as the ratio of the C8-C14 hydrocarbon content in the hydrocracking effluent to the C8-C14 hydrocarbon content in the first reaction section feed.

As used herein, wherever the reaction steps are defined to take place in “reactors", said expression is used for illustrative purposes mainly. A person skilled in the art contemplates that any “reactor” is in practice implemented as a reactor system that may consist of one or more reactors. Whether the reactors are actually arranged in a single reactor or several reactors is a matter of engineering, and may be influenced by practical issues such as maximum height of the facility at the site, reactor diameter, regulatory and maintenance issues at the site, wind conditions at the site, and/or available equipment. Analogously, the “fractionation” may take place in a fractionation system, typically comprising e.g. separation and distillation units, which may be arranged according to conventional engineering practice in the field.

Catalyst characteristics, such as total number of acid sites, refers in the context of this disclosure to the catalyst characteristics in their ready-to-use state, in the beginning of the present process.

As used herein, the term catalyst deactivation refers to decreased activity of the catalyst (reflected by the amount of unconverted feed in the reaction section effluent) and/or decreased selectivity of the catalyst (reflected by decreased amount of desired reaction products in the reaction section effluent) at a given time point (t _n ), compared to the activity and/or selectivity of the catalyst in the beginning of the present process (to). As used herein, the term catalyst deactivation is not limited to any specific deactivation type or mechanism, although the catalyst deactivation observed in the present process is generally believed to be attributed to poisoning and fouling phenomena, and encompasses both reversible and irreversible deactivation.

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 feeds, components, compounds, or compositions, or as biogenic feeds, components, compounds, or compositions.

As used herein, the term fossil 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 utilised from ground/underground sources.

The term circular refers to recycled material typically originating from non-renewable sources. For example, the term circular may refer to recycled material originating from waste plastics. Said renewable and circular, and fossil compounds or 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 compounds or compositions are differentiated based on their origin and information thereof provided by the producer.

Chemically the renewable or fossil origin of any organic compounds, including hydrocarbons, can be determined by suitable method for analysing 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 ( ¹⁴ C) 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 analysing the ratio of ¹² C and ¹⁴ C 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, components, and compositions and distinguishing them from non-renewable, fossil materials in reaction section feeds, reaction section effluents, separated product fractions and various blends thereof. 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 preferably refers to a material having a biogenic carbon content of more than 50 wt-%, especially more than 60 wt-% or more than 70 wt-%, preferably more than 80 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)).

The present disclosure provides a process for producing at least one liquid transportation fuel component, the process comprising: providing a paraffinic hydrocarbon feed comprising at least 60 wt-% paraffins of the total weight of the paraffinic hydrocarbon feed, of which paraffins at least 5 wt-% are isoparaffins; subjecting a first reaction section feed comprising the paraffinic hydrocarbon feed and optionally a recycle stream and/or a side cut to hydrocracking (HC) in a first reaction section in the presence of a hydrocracking catalyst to obtain a hydrocracking effluent; subjecting a second reaction section feed comprising the hydrocracking effluent to hydroisomerisation (HI) in a second reaction section in the presence of a hydroisomerisation catalyst to obtain a hydroisomerisation effluent; and feeding the hydroisomerisation effluent to a fractionation and recovering from the fractionation at least one or more liquid transportation fuel components, and optionally the recycle stream and/or the side cut.

Preferably, the present process is a continuous process.

Typically, in the present process at least one or more of an aviation fuel component, a diesel fuel component, a gasoline fuel component, and/or a marine fuel component is recovered from the fractionation, preferably at least an aviation fuel component, more preferably at least an aviation fuel component and a diesel fuel component. With the present process it is possible to obtain higher yield of aviation fuel component, particularly higher combined yield of aviation and diesel fuel components, and/or to improve their quality, compared to conventional processes for producing fuel components by hydrodeoxygenation (HDO) and HI of renewable fats and oils. These benefits were shown in experiments comparing subjecting the paraffinic hydrocarbon feed to only HI, to only HC, or to HI followed by HC, before fractionation and product recovery.

With the present process it is possible to produce an aviation fuel component having excellent cold properties and hence usable in aviation fuels, even with high blending ratio. Also, the present process enables extending the HC and/or HI catalyst lifetime and enables utilisation of a broader range of feeds, including heavier and more impure feeds, compared to conventional processes for producing fuel components by HDO and HI of renewable fats and oils. Furthermore, the present process enables flexible adjustment of product selectivity towards the various liquid transportation fuel components, particularly to aviation fuel component and to diesel fuel component based on e.g. market dynamics, even towards the end of the lifetime of the HC catalyst and/or HI catalyst. The present process suggests subjecting an isoparaffin-containing paraffinic hydrocarbon feed to hydrocracking in a first reaction section, which hydrocracking cracks longer paraffin molecules for example to paraffins boiling in the aviation fuel range. Having at least some isoparaffins in the paraffinic hydrocarbon feed helps to reach desired degree of effective cracking in the first reaction section at milder operating conditions (compared to a paraffinic hydrocarbon feed containing no or just low amount of isoparaffins), thereby efficiently reducing formation of low-profit products, such as fuel gases. Subjecting the isoparaffin-containing paraffinic hydrocarbon feed to hydrocracking in the first reaction section may even isomerise n- paraffins in the feed as well as n-paraffins formed in the course of cracking reactions, and further isomerise isoparaffins by increasing the number of branches in isoparaffin molecules producing multiple-branched isoparaffins. Hence, by operating the process of the present disclosure, the isomerisation degree of the paraffinic hydrocarbon feed may be maintained, but preferably increased, in the first reaction section. This is beneficial for achieving high isoparaffin content in the HC effluent, even towards the end of the HC catalyst lifetime. Preferably, by operating the process of the present disclosure the content of multiple- branched isoparaffins in the HC effluent is efficiently elevated, compared to their content in the first reaction section feed. Enhanced degree of effective cracking without excess formation of gaseous hydrocarbons in the first reaction section, and an increased isoparaffin content of the HC effluent, are beneficial both for the yield and the quality of the transportation fuel component(s) recovered from the fractionation, especially for the yield and quality of the aviation fuel component. The hydrocracking in the first reaction section may increase the yield of aviation fuel component as well as improve its quality, for example its cold properties. The hydroisomerisation in the second reaction section (further) reduces content of n-paraffins and (further) increases content of isoparaffins, preferably content of multiple-branched isoparaffins, in the HI effluent and in the recovered fuel component(s).

During continued operation of the catalytic HC and HI, the catalysts deactivate gradually for example due to impurities in process streams and coking. The present process is highly flexible and involves various possibilities to adjust the yield and/or quality of the recovered liquid transportation fuel component(s), and to prolong the lifetime of the HI and HC catalysts. Convenient means for adjusting the yield and/or quality of the recovered liquid transportation fuel component(s) and/or to respond to the catalyst deactivation, or changing market needs, may include for example adjusting the amount of the recycle stream and/or the side cut optionally recovered and subjected to hydrocracking, splitting the paraffinic hydrocarbon feed between the first reaction section and the second reaction section in adjustable weight ratio, and/or in embodiments recovering the recycle stream adjusting the amount of heavies optionally removed from the process as diesel fuel component, as marine fuel component, or as some other heavy product component. The various possibilities to adjust the process enable the use of paraffinic hydrocarbon feeds that have higher impurity content compared to conventional processes for producing liquid fuel components by HDO and HI of renewable fats and oils. Also, the hydrocracking step enables use of feeds comprising heavier and longer chain molecules compared to said conventional processes for producing liquid fuel components, typically diesel components, while being able to produce lower-boiling liquid transportation fuel components, particularly aviation fuel component, with good yields and quality.

In certain preferred embodiments of the present process, the second reaction section feed further comprises a portion of the paraffinic hydrocarbon feed, and the paraffinic hydrocarbon feed is split between the first reaction section feed and the second reaction section feed. These embodiments provide further flexibility for operating the present process, and possibility to adjust the process e.g. according to fluctuations in the characteristics of the paraffinic hydrocarbon feed. Furthermore, the process may be operated even more precisely in order to meet targeted yields and qualities of more than one recovered component at a time. In this way it may be possible to avoid situations where targeted yield and quality of one recovered fuel component are met but at the expense of producing over-quality of another recovered fuel component (e.g. producing a diesel fuel component having unnecessarily low cloud point).

In certain preferred embodiments, the present process comprises recovering from the fractionation the recycle stream and feeding the recycle stream to the first reaction section as part of the first reaction section feed and/or recovering from the fractionation the side cut and feeding the side cut to the first reaction section as part of the first reaction section feed and/or feeding a portion of the paraffinic hydrocarbon feed to the second reaction section as part of the second reaction section feed, which portion of the paraffinic hydrocarbon feed is obtained by splitting the paraffinic hydrocarbon feed between the first reaction section and the second reaction section. These embodiments provide (further) enhanced flexibility for operating the process, including possibility to adjust the process e.g. according to fluctuations in the characteristics of the paraffinic hydrocarbon feed, according to the demand of the share and quality of the produced diesel and aviation fuel components, and/or according to the changing activity and/or selectivity of the HI and HC catalysts throughout their lifetimes. Additionally, the process may be operated even more precisely in order to meet targeted yields and qualities of more than one recovered component at a time, without a need to produce over-quality of some other recovered fuel component.

In the present process, the paraffinic hydrocarbon feed subjected to hydroisomerisation in the first reactor comprises at least 60 wt-% paraffins of the total weight of the paraffinic hydrocarbon feed, of which paraffins at least 5 wt-% are isoparaffins. This means that when the paraffinic hydrocarbon feed comprises 60 wt-% paraffins of the total weight of the paraffinic hydrocarbon feed, then at least 5 wt-% of the total weight of paraffins in the paraffinic feed, i.e. at least 3 wt-% of the total weight of the paraffinic hydrocarbon feed, are isoparaffins. Typically, the paraffinic hydrocarbon feed comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-%, even more preferably at least 95 wt-% paraffins of the total weight of the paraffinic hydrocarbon feed. The paraffinic hydrocarbon feed of the present disclosure may contain minor amounts of olefins, preferably less than 5 wt-%, more preferably less than 1 wt-%, based on the total weight of the paraffinic hydrocarbon feed, as well as minor amounts of aromatics and/or naphthenes. An advantage of using a highly paraffinic hydrocarbon feed in the present process is that paraffins crack relatively easily and at milder conditions when subjected to HC compared to e.g. cyclic hydrocarbons. Also, paraffins are isomerised relatively easily and at milder conditions when subjected to HI.

Of the paraffins in the paraffinic hydrocarbon feed of the present disclosure, typically at least 8 wt-%, or at least 10 wt-%, preferably at least 20 wt-%, further preferably at least 30 wt-%, more preferably at least 40 wt-%, further more preferably at least 50 wt-%, even more preferably at least 60 wt-%, most preferably at least 70 wt-%, or at least 80 wt-% are isoparaffins of the total weight of paraffins in the paraffinic hydrocarbon feed.

A high weight-ratio (wt-%:wt-%) of i-paraffins to n-paraffins in the paraffinic hydrocarbon feed may contribute to enhanced degree of effective cracking during HC in the first reaction section, as i-paraffins are believed to be more prone to crack compared to n-paraffins of same carbon number. Moreover, the presence of isoparaffins in the paraffinic hydrocarbon feed may yield a HC effluent with a higher content of multiple-branched isoparaffins. Similar considerations may apply to the content of the multiple-branched isoparaffins, as detailed later in connection with the compositions of the first reaction section feed. Hence, in certain preferred embodiments, the paraffinic hydrocarbon feed comprises at least 3 wt-%, preferably at least 5 wt-%, more preferably at least 10 wt-%, even more preferably at least 15 wt-% multiple-branched isoparaffins of the total weight of paraffins in the paraffinic hydrocarbon feed. Preferably, the first reaction section feed may comprise the largest portion of the paraffinic hydrocarbon feed compared to the other feed stream(s) of the process.

Preferably, the paraffinic hydrocarbon feed of the present disclosure comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-%, even more preferably at least 95 wt-% hydrocarbons having a carbon number within a range from C12 to C30, of the total weight of the paraffinic hydrocarbon feed. In certain particularly preferred embodiments, the paraffinic hydrocarbon feed comprises at least 70 wt-%, preferably at least 80 wt-%, more preferably at least 90 wt-%, even more preferably at least 95 wt-% hydrocarbons having a carbon number within a range from C14 to C22, of the total weight of the paraffinic hydrocarbon feed. Paraffinic hydrocarbon feeds having a high content of C12-C30 hydrocarbons are preferred as they allow good yields of two or more liquid transportation fuel components of different kinds. C14-C22 hydrocarbons are particularly preferred for the same reason, and also because they are readily available for example from conventional hydrodeoxygenation processes of vegetable oils, animal fats and/or microbial oils, comprising fatty acids. To increase the yield of aviation and/or diesel fuel component, it is particularly preferred that the paraffinic hydrocarbon feed comprises at least 50 wt-%, preferably at least 60 wt- %, more preferably at least 70 wt-%, even more preferably at least 80 wt-%, or at least 90 wt-% C16+ paraffins of the total weight of paraffins in the paraffinic hydrocarbon feed. In certain embodiments, the paraffinic hydrocarbon feed comprises at least 50 wt-%, preferably at least 60 wt-%, more preferably at least 70 wt-% C17+ paraffins of the total weight of paraffins in the paraffinic hydrocarbon feed. In certain embodiments the paraffinic hydrocarbon feed comprises at least 40 wt-%, preferably at least 50 wt-%, more preferably at least 60 wt-% C18+ paraffins of the total weight of paraffins in the paraffinic hydrocarbon feed. This kind of compositions are attainable by suitably selecting heavier paraffinic hydrocarbon feeds, particularly by suitably selecting feedstocks such as oxygenated hydrocarbons, for producing them. Examples of suitable heavier oxygenated hydrocarbon feeds include oil from energy crops such as Brassica species, algal oils, crude tall oil (CTO), tall oil fatty acids (TOFA), tall oil pitch (TOP), and/or lignocellulosics-originating feeds. C17+ paraffins are also obtainable by Fischer-Tropsch conversion of syngas. Subjecting C16+, or C17+, or C18+ paraffins to hydrocracking in the first reaction section is beneficial in that it may improve quality, but particularly increase the yield of the aviation and diesel fuel components. C16+ n -pa raffins have poor cold properties while C18+ n-paraffins and C19+ paraffins generally boil outside the aviation fuel boiling range. Furthermore, this kind of paraffinic hydrocarbon feed compositions are convenient for increasing the content of heavier paraffins in the first reaction section feed to provide further benefits, as explained hereinafter.

The paraffinic hydrocarbon feed may comprise any suitable paraffinic hydrocarbon compositions or combinations thereof. Preferably, in the present process the step of providing the paraffinic hydrocarbon feed comprises subjecting a hydrotreatment feed to a (catalytic) hydrotreatment, preferably subjecting an oxygenated hydrocarbon feed to (catalytic) hydrodeoxygenation, optionally followed by an initial (catalytic) hydroisomerisation to obtain a paraffinic hydrotreatment effluent, wherein the hydrotreatment feed preferably comprises at least one or more of vegetable oil(s), animal fat(s), microbial oil(s), thermally liquefied organic waste and residue(s), and/or enzymatically liquefied organic waste and residue(s), more preferably the oxygenated hydrocarbon feed comprises at least one or more of vegetable oil(s), animal fat(s), and/or microbial oil(s), and/or subjecting a syngas to a Fischer-Tropsch (FT) conversion, optionally followed by an initial dewaxing, to obtain a paraffinic FT effluent; subjecting the paraffinic hydrotreatment effluent and/or the paraffinic FT effluent to a gas-liquid separation, and optionally to a paraffinic feed fractionation to provide the paraffinic hydrocarbon feed. By gas-liquid separation is meant removing at least compounds that are gaseous at NTP.

While e.g. paraffinic FT effluents of fossil origin are readily available (in addition to FT effluents of renewable origin), preferably the paraffinic hydrocarbon feed of the present disclosure is at least partially renewable, i.e. comprises biogenic components. In certain preferred embodiments, the biogenic carbon content of the paraffinic hydrocarbon feed is at least 50 wt-%, preferably at least 70 wt-%, more preferably at least 90 wt-%, even more preferably at least 95 wt-%, or even about 100 wt-%, based on the total weight of carbon (TO) in the paraffinic hydrocarbon feed, preferably as determined according to EN 16640 (2017).

In certain embodiments, the paraffinic hydrocarbon feed comprises or consists essentially of a degassed paraffinic Fischer-Tropsch effluent, or a fraction thereof. Fischer-Tropsch process involves a catalytic conversion of syngas comprising carbon monoxide and hydrogen, typically to a substantially Gaussian distribution of hydrocarbon chains, mainly n- paraffins, having a wide carbon chain length distribution, such as from C2 to C100+, typically from about C5 to about C50. The syngas used in the FT process may be produced from renewable materials, natural gas, coal, or a combination thereof. FT effluents are typically highly paraffinic comprising mainly n-paraffins. The catalytic FT conversion of syngas may result in a minor degree of isomerisation, the FT effluent typically comprising about 10 wt-% or less isoparaffins of the total weight of the FT effluent. The isoparaffin content in the paraffinic FT effluent may be efficiently increased by subjecting the paraffinic FT effluent to an initial dewaxing using any dewaxing technology, such as isodewaxing based on bifunctional catalysts, for example Ni-W and zeolite or zeolite-type material, e.g. HZSM-5, ZSM-22, ZSM-23, and/or SAPO11, on amorphous aluminosilicate, preferably combined with hydrogen pretreating and hydrofinishing.

Preferably, the paraffinic hydrocarbon feed of the present disclosure comprises or consists essentially of a degassed paraffinic hydrotreatment effluent, or a fraction thereof, particularly as obtained by (catalytic) hydrotreatment of a hydrotreatment feed, comprising at least one or more of vegetable oil(s), animal fat(s), microbial oil(s), thermally liquefied organic waste and residue(s), and/or enzymatically liquefied organic waste and residue(s), more preferably at least one or more of vegetable oil(s), animal fat(s), and/or microbial oil(s), optionally followed by an initial (catalytic) hydroisomerisation, to obtain a paraffinic hydrotreatment effluent, followed by subjecting the paraffinic hydrotreatment effluent to a gas-liquid separation, and optionally to a paraffinic feed fractionation to provide the degassed hydrotreatment effluent, or a fraction thereof. By the term “hydrotreatment”, sometimes also referred to as hydroprocessing, is meant a catalytic process of treating organic material in the presence of molecular hydrogen. Preferably, hydrotreatment removes oxygen from organic oxygen compounds as water i.e. hydrodeoxygenation (HDO), sulphur from organic sulphur compounds as dihydrogen sulphide (H ₂ S), i.e. hydrodesulphurisation, (HDS), nitrogen from organic nitrogen compounds as ammonia (NH3), i.e. hydrodenitrogenation (HDN), halogens, for example chlorine from organic chloride compounds as hydrochloric acid (HCI), i.e. hydrodechlorination (HDCI), and metals by hydrodemetallization, and/or hydrogenates olefinic bonds if present in the hydrotreatment feed. In the present context, hydrotreatment may also cover the optional initial hydroisomerisation conducted in the presence of molecular hydrogen and preferably initial HI catalyst.

Preferably, the paraffinic hydrocarbon feed of the present disclosure comprises or consists essentially of a degassed hydrotreatment effluent, or a fraction thereof, particularly as obtained by hydrodeoxygenation (HDO) of at least one or more of vegetable oil(s), animal fat(s), and/or microbial oil(s), followed by an initial hydroisomerisation. The initial hydroisomerisation may be conducted e.g. by subjecting a HDO effluent to gas-liquid separation to remove water and at least compounds that are gaseous at NTP, and contacting the degassed HDO effluent with an initial HI catalyst, preferably as disclosed in connection with the HI catalyst used in the second reaction section, under HI operating conditions, preferably as disclosed in connection with the HI in the second reaction section.

In certain preferred embodiments, providing the paraffinic hydrocarbon feed comprises subjecting an oxygenated hydrocarbon feed, preferably in a hydrodeoxygenation (HDO) reactor, to hydrodeoxygenation in the presence of a hydrodeoxygenation catalyst to obtain a hydrodeoxygenation effluent, and subjecting the hydrodeoxygenation effluent to gasliquid separation and optionally to paraffinic feed fractionation to obtain as the paraffinic hydrocarbon feed the degassed hydrocarbon effluent or a fraction thereof, wherein the hydrodeoxygenation is preferably conducted at a temperature within a range from 200 °C to 500 °C, a pressure within a range from 1 MPa to 20 MPa, a H2 partial pressure at the inlet of the reactor within a range from 1 MPa to 20 MPa, a weight hourly space velocity within a range from 0.1 to 10 kg oxygenated hydrocarbon feed per kg catalyst per hour, and a H2 to oxygenated hydrocarbon feed ratio selected from a range from 50 to 2000 normal liters H2 per liter oxygenated hydrocarbon feed. Preferably, the oxygenated hydrocarbon feed comprises at least one or more of vegetable oils, animal fats, and/or microbial oils. Hydrodeoxygenation is preferably conducted as described in the prior art publications, such as FI100248B, EP1741768A1 , EP2155838B1 or Fl 129220 B1. Preferably, the HDO catalyst is a sulphided catalyst comprising at least one or more metals from Group VIII of the Periodic Table and/or from Group VIB of the Periodic Table, preferably at least one or more of Ni, Mo, W, and/or Co, even more preferably at least one or more of Ni and/or Co and Mo and/or W, such as NiMo, CoMo, NiCoMo, NiW, and/or NiMoW. These catalysts are efficient, readily available, and tolerate typical impurities of fatty feedstocks well. If using a catalyst having hydrodewaxing properties, such as a catalyst containing NiW, in the hydrodeoxygenation as the hydrodeoxygenation catalyst or as a cocatalyst, HDO effluent with somewhat elevated isoparaffin content may be attained.

The optional paraffinic feed fractionation is typically conducted in a fractionation unit different from the fractionation unit(s) used to recover the liquid transportation fuel component(s), and optionally the recycle stream and/or the side cut(s). The optional paraffinic feed fractionation may be regarded separate from the fractionation of the present process, which fractionation of the present process comprises fractionation to recover the liquid transportation fuel component(s) and optionally the recycle stream and/or side cut.

The present process comprises subjecting a first reaction section feed comprising the paraffinic hydrocarbon feed and optionally a recycle stream and/or a side cut, to hydrocracking in a first reaction section in the presence of a hydrocracking catalyst to obtain a hydrocracking effluent. Hydrocracking heavy paraffins in the first reaction section feed enables increasing yield of aviation fuel component. Additionally, hydrocracking provides flexibility to use of different kinds of paraffinic hydrocarbon feeds, in particular it allows use of a wide variety of oxygenated hydrocarbon feeds converted thereto. Generally, hydrocracking in the first reaction section is operated so that cracking reactions, especially those enhancing the degree of effective cracking, are more abundant than in the hydroisomerisation in the second reaction section. Preferably cracking reactions, especially those enhancing the degree of effective cracking, prevail in the hydrocracking in the first reaction section, yet generally without excessive cracking and excessive fuel gas formation.

Preferably, the first reaction section feed comprises elevated or even high level of isoparaffins, and preferably at least some multiple-branched isoparaffins. Presence of isoparaffins in the first reaction section feed may be considered beneficial as it is believed to ease cracking reactions in the first reaction section, and to contribute beneficially to the degree of effective cracking. When a desired degree of effective cracking, particularly to C8-C14 hydrocarbons but also to lighter non-gaseous hydrocarbons, is achieved in the first reaction section at milder operating conditions, excessive cracking may be avoided, and formation of gaseous hydrocarbons reduced. Hence, preferably the first reaction section feed comprises at least 30 wt-%, preferably at least 40 wt-%, further preferably at least 50 wt-%, more preferably at least 60 wt-%, further more preferably at least 70 wt-%, even more preferably at least 80 wt-% isoparaffins of the total weight of paraffins in the first reaction section feed. Also presence of multiple-branched i-paraffins in the first reaction section feed may contribute beneficially to the degree of effective cracking in the first reaction section. It was surprisingly found that when increasing the content of multiple-branched isoparaffins in the first reaction section feed also the weight ratio of the aviation fuel component to the diesel fuel component recovered from the fractionation increased, as shown by the Examples. Furthermore, without being bound to any theory, it is believed that a multiple- branched isoparaffin is more likely to form upon cracking in the first reaction section two branched paraffin molecules instead of one branched and one n-paraffin, which may increase the isoparaffin content of the HC effluent. Hence, an increased content of multiple- branched isoparaffins in the first reaction section feed may improve the cold properties of the recovered liquid transportation fuel component(s), especially the cold properties of aviation fuel component and/or diesel fuel component, and/or RON of gasoline fuel component. Elevated content of multiple-branched isoparaffins may be particularly beneficial towards the end of the HI catalyst lifetime, when the HI catalyst has already started to lose of its activity and/or selectivity. Hence, the first reaction section feed may comprise at least 3 wt-% or at least 5 wt-%, preferably at least 10 wt-%, more preferably at least 15 wt-%, even more preferably at least 20 wt-% multiple-branched isoparaffins of the total weight of paraffins in the first reaction section feed. It is generally beneficial to start operating the first reaction section in the beginning of the run at a low temperature, using for example lowest feasible temperature in the range specified later for hydrocracking, as that provides the widest window for increasing the temperature upon gradual catalyst deactivation. Elevated contents of isoparaffins, and preferably multiple-branched isoparaffins in the first reaction section feed are thus preferred also for prolonging the runtime and catalyst change/regeneration intervals.

In the present process, the first reaction section feed may comprise a recycle stream and/or a side cut recovered from the fractionation, in addition to the paraffinic hydrocarbon feed. The HI in the second reaction section efficiently increases the degree of isomerisation, including isomersation of n-paraffins and/or further isomerization of mono- and multiple- branched isoparaffins in the second reaction section feed. Hence, the HI effluent fed to the fractionation contains a high amount of isoparaffins, and at least some multiple-branched isoparaffins. Therefor also the recycle stream and/or the side cut optionally recovered from the fractionation fed with the HI effluent contain a high amount of isoparaffins, and typically at least some multiple-branched isoparaffins. As explained in the foregoing, elevated content of isoparaffins and optionally at least some multiple-branched isoparaffins in the first reaction section feed provides certain benefits. Hence, in certain preferred embodiments, the present process comprises recovering from the fractionation the recycle stream and/or the side cut, and feeding the recycle stream and/or the side cut to the first reaction section as part of the first reaction section feed. Preferably, the recycle stream and/or the side cut comprises at least 50 wt-%, preferably at least 60 wt-%, more preferably at least 70 wt-%, even more preferably at least 80 wt-% isoparaffins of the total weight of paraffins in the recycle stream or side cut, respectively; and/or at least at least 10 wt-%, preferably at least 15 wt-%, more preferably at least 20 wt-%, even more preferably at least 30 wt-% multiple-branched isoparaffins of the total weight of paraffins in the recycle stream or side cut, respectively. Such high isoparaffin and elevated multiple-branched isoparaffin contents are obtainable to the recycle stream and/or to the side cut because of the specified order of the HC and the HI steps. By incorporating the recycle stream and/or the side cut to the first reaction section feed, it is possible to increase the aviation fuel component yield, and also to improve the quality of the recovered transportation fuel component(s), especially of the diesel fuel component and/or the aviation fuel component.

The recycle stream and/or the side cut may be incorporated into the first reaction section feed within wide ratios. By adjusting the ratio(s) in which the recycle stream and/or the side cut are optionally incorporated into the first reaction section feed it is possible to adjust the weight-ratio of the aviation fuel component to the diesel fuel component recovered from the fractionation, as well as their quality, particularly cold properties. This is a valuable and simple means for adjusting the share(s) and quality of the produced diesel and aviation fuel components, for example to respond to fluctuations and/or seasonal variation in the market demand of these products or different grades thereof. Preferably, the first reaction section feed comprises the paraffinic hydrocarbon feed and the recycle stream and/or the side cut, and the weight ratio of the paraffinic hydrocarbon feed to a sum amount of the recycle stream and/or the side cut is within a range from 10:90 to 90:10, preferably from 20:80 to 80:20.

In certain preferred embodiments, the first reaction section feed consists essentially of the paraffinic hydrocarbon feed and optionally recycle stream and/or the side cut.

In certain preferred embodiments, a side cut is recovered from the fractionation and fed to the first reaction section as part of the first reaction section feed. HC in the first reaction section and HI in the second reaction section may have an impurity-removing effect on the treated stream, especially when accompanied by a gas-liquid separation. Incorporating even a small amount of a highly pure side cut to the first reaction section feed may reduce or dilute the impurity content of the first reaction section feed. This may slow down the catalyst deactivation. The side cut is typically a fraction rich in C14-18 hydrocarbons, more preferably rich in C15-C17 hydrocarbons. The side cut is preferably a relatively narrow fraction to allow precise modification of the boiling point distribution of the total feed to fractionation. Hence, in certain preferred embodiments the side cut has T5 and T95 temperatures, as determined according to EN ISO 3405-2019, within a range from 250 °C to 320 °C, preferably within a range from 260 °C to 310°C, more preferably within a range from 270 °C to 300°C; and/or difference between T95 and T5 temperatures (95 vol-% and 5 vol-% recovered, EN ISO 3405-2019) of 40 °C or less, preferably 30 °C or less, more preferably 20 °C or less.

In certain preferred embodiments, a recycle stream is recovered from the fractionation and fed to the first reaction section as part of the first reaction section feed. It has been found that when increasing the content of heavier paraffins in the first reaction section feed, also the weight ratio of the diesel fuel component to the aviation fuel component recovered from the fractionation may be increased, as shown by the Examples. By adjusting the ratio in which the recycle stream is incorporated into the first reaction section feed, it is possible to adjust the weight-ratio of the diesel fuel component to the aviation fuel component recovered from the fractionation. This is a valuable and simple means for adjusting the share(s) of produced diesel and aviation fuel components, for example to respond to fluctuations and/or seasonal variation in the market demand of these products or different grades thereof. In certain preferred embodiments, the recycle stream has a T5 temperature (5 vol-% recovered, EN ISO 3405-2019) of 270 °C or higher; and/or a T5 temperature within a range from 270 °C to less than 300 °C, preferably within a range from 270 °C to less than 295 °C, more preferably within a range from 270 °C to less than 290 °C; and/or an initial boiling point (IBP, EN ISO 3405-2019) less than 290 °C, preferably less than 288 °C, more preferably less than 285 °C. Preferably, the T5 temperature of the recycle stream is selected so that at least a portion of any C16 n-paraffins present in the total feed subjected to the fractionation, such as C16 n-paraffins present in the HI effluent, if any, are recovered in the recycle stream. Recovering C16 n-paraffins in the recycle stream may be attained by suitably selecting the IBP or T5 temperature of the recycle stream. C16 n-paraffins have a boiling point of 287 °C (at standard atmospheric pressure), but as fractionations, such as distillation separations, are not perfectly sharp, C16 n-paraffins may be recovered over a temperature range around that boiling point. Recycling at least some of C16 n-paraffins to the first reaction section to be subjected to hydrocracking is beneficial as C16 n-paraffins have a relatively high melting point. Hence, the presence of C16 n-paraffins in any significant amounts for example in the recovered aviation fuel component might even render it unusable in aviation fuel compositions, due to poor cold properties, especially poor freezing point. In any event, C16 n-paraffins in the preferably recovered aviation fuel component impairs its cold properties i.e. increases one or more of cloud point, freezing point, pour point, and cold filter plugging point, and subzero kinematic viscosity, compared to aviation fuel components with less or without C16 n-paraffin content. The amount of n- paraffins, including C16 n-paraffins, in the total feed subjected to the fractionation increases upon HI catalyst deactivation, and may also be formed by cracking in the first reaction section (and/or the second reaction section).

The recycle stream characteristics as described in the foregoing are particularly beneficial in view of degree of effective cracking in the hydrocracking, forming hydrocarbons boiling in the aviation fuel range, as generally paraffins are more prone to crack than cyclic hydrocarbons, longer paraffins are more prone to crack than shorter paraffins, and isoparaffins and especially multiple-branched isoparaffins are foreseen more prone to crack than n-paraffins. Additionally, these embodiments facilitate easy separation by mere splitting of e.g. diesel fuel component, marine fuel component, base oil component, and/or transformer oil component from the recycle stream, just to name a few examples of components that may be separated from such recycle streams.

In certain particularly preferred embodiments, the first reaction section feed comprises at least 85 wt-%, preferably at least 90 wt-%, more preferably at least 95 wt-% C16+ paraffins of the total weight of paraffins in the first reaction section feed, and/or at least 40 wt-%, preferably at least 50 wt-%, more preferably at least 60 wt-% C18+ paraffins of the total weight of paraffins in the first reaction section feed. This kind of compositions are attainable by suitably selecting heavier paraffinic hydrocarbon feeds, and/or by incorporating sufficient amount of the recycle stream into the first reaction section feed. Subjecting C16+ paraffins to hydrocracking in the first reaction section is beneficial in that it may increase yield and/or improve quality of aviation fuel component. C16+ n-paraffins have poor cold properties while C18+ n-paraffins and 019+ paraffins generally boil outside the aviation fuel boiling range. Furthermore, as explained in the foregoing, by increasing the content of heavier paraffins in the first reaction section feed, also the weight ratio of the diesel fuel component to the aviation fuel component recovered from the fractionation may be adjusted higher.

In the present process, the hydrocracking in the first reaction section may be conducted at a temperature within a range from 200 °C to 500 °C, preferably from 220 °C to 430 °C, more preferably from 280 °C to 400 °C, a pressure within a range from 0.5 MPa to 20 MPa, preferably from 1 MPa to 20 MPa, more preferably from 3 to 15 MPa, a H2 partial pressure at the inlet of the first reaction section within a range from 0.5 MPa to 20 MPa, preferably from 1 MPa to 20 MPa, more preferably from 3 MPa to 15 MPa, a weight hourly space velocity within a range from 0.1 to 10, preferably from 0.2 to 10, more preferably from 0.4 to 8, even more preferably from 0.5 to 5 kg first reaction section feed per kg catalyst per hour, and a Hz to first reaction section feed ratio within a range from 10 to 2000, preferably from 50 to 1000 normal liters Hz per liter first reaction section feed. Typically in the present process, the hydrocracking in the first reaction section is conducted at a temperature within a range from 200 °C to 500 °C, a pressure within a range from 0.5 MPa to 20 MPa, a Hz partial pressure at the inlet of the first reaction section within a range from 0.5 MPa to 20 MPa, a weight hourly space velocity within a range from 0.1 to 10 first reaction section feed per kg catalyst per hour, and a Hz to first reaction section feed ratio within a range from 10 to 2000 normal liters Hz per liter first reaction section feed.

According to certain preferred embodiments, the hydrocracking in the first reaction section is conducted at a temperature within a range from 220 °C to 430 °C, a pressure within a range from 1 MPa to 20 MPa, a Hz partial pressure at the inlet of the first reaction section within a range from 1 MPa to 20 MPa, a weight hourly space velocity within a range from 0.2 to 10 kg first reaction section feed per kg catalyst per hour, and a Hz to first reaction section feed ratio within a range from 50 to 1000 normal liters Hz per liter first reaction section feed. When operating the HC at lower temperatures and sufficiently high pressures, aromatizing side reactions may be better suppressed or even dearomatisation enhanced .The first reaction section and the second reaction section may be arranged in the same reactor or in separate reactors. Preferably, the first reaction section and the second reaction section are arranged in separate reactors.

When operating the first reaction section and the second reaction section in separate reactors, the HC effluent is preferably subjected to gas-liquid separation, i.e. removal of at least compounds that are gaseous at NTP. This can be done e.g. as an integral step within the first reaction section or reactor, or in a separate gas-liquid separator, before feeding the HC effluent to the second reaction section or reactor.

Preferably, hydrocracking in the first reaction section is operated so that the ratio of the wt- % amount of isoparaffins of the total weight of paraffins in the HC effluent to the wt-% amount of isoparaffins of the total weight of paraffins in the first reaction section feed is at least 0.5, or at least 0.7, or at least 0.8, or at least 0.9, or at least 1.0; and/or so that the ratio of the C8-C14 hydrocarbon content in the HC effluent to the C8-C14 hydrocarbon content in the first reaction section feed is at least 1.1 , preferably at least 1.3, more preferably at least 1.5, even more preferably at least 1.8 or at least 2.0.

In certain preferred embodiments, hydrocracking in the first reaction section is operated so that the ratio of content of C1-C4 hydrocarbons, formed during hydrocracking, in the (total) HC effluent to the content of C1-C4 hydrocarbons in the (total) first reaction section feed is within a range from 1.1 to 5.0, preferably from 1.1 to 4.0, more preferably from 1.2 to 3.0; and/or so that the (total) HC effluent comprises C1-C4 hydrocarbons less than 20 wt-%, or less than 10 wt-%, or less than 5 wt-% of the total weight of the HC effluent.

These may be achieved especially when using the first reaction section feed as specified in the foregoing and/or operating the first reaction section within the hydrocracking operating conditions specified in the foregoing and/or in the presence of a HC catalyst as defined hereinafter, particularly in the presence of a non-sulphided bifunctional HC catalyst, preferably a non-sulphided bifunctional HC catalyst comprising at least one or more Group VIII noble metals, more preferably Pt and/or Rd.

Typically, the HC effluent comprises at least 60 wt-%, preferably at least 70 wt-%, more preferably at least 80 wt-%, even more preferably at least 90 wt-% or at least 95 wt-% paraffins of the total weight of the HC effluent. The HC effluent may even consist essentially of paraffins.

According to a preferred embodiment, the HC effluent comprises at least 30 wt-%, preferably at least 40 wt-%, more preferably at least 50 wt-%, even more preferably at least 60 wt-%, or at least 70 wt-% isoparaffins of the total weight of paraffins in the HC effluent; and/or at least 3 wt-% or at least 5 wt-%, preferably at least 10 wt-%, more preferably at least 15 wt-%, even more preferably at least 20 wt-% multiple-branched isoparaffins of the total weight of paraffins in the HC effluent. In other words, the isomerisation degree of the HC effluent is not necessarily significantly lower than in the first reaction section feed, or may be the same or even higher. This may be attained particularly by using a bifunctional HC catalyst and/or a first reaction section feed having elevated content of isoparaffins and/or multiple-branched isoparaffins.

In the present process a second reaction section feed comprising the hydrocracking effluent, and optionally a portion of the paraffinic hydrocarbon feed, is subjected to hydroisomerisation in a second reaction section in the presence of a hydroisomerisation catalyst to obtain a hydroisomerisation effluent. Generally, in the context of the present disclosure, HI of the second reaction section feed in the second reaction section is operated so that isomerisation reactions prevail while cracking reactions are controlled or suppressed.

In certain preferred embodiments, the second reaction section feed consists essentially of the hydrocracking effluent, and optionally a portion of the paraffinic hydrocarbon feed. Preferably, the hydroisomerisation in the second reaction section is 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 400 °C, a pressure within a range from 1 MPa to 20 MPa, preferably from 2 MPa to 15 MPa, or from 3 MPa to 10 MPa, a H2 partial pressure at the inlet of the second reaction section within a range from 1 MPa to 20 MPa, preferably from 2 MPa to 15 MPa, or from 3 to 10 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 second reaction section feed per kg catalyst per hour, and a H2 to second reaction section feed ratio within a range from 10 to 2000, preferably from 50 to 1000 normal liters H2 per liter second reaction section feed.

According to certain embodiments, the hydroisomerisation in the second reaction section is conducted at a temperature within a range from 200 °C to 500 °C, a pressure within a range from 1 MPa to 20 MPa, a H2 partial pressure at the inlet of the second reaction section within a range from 1 MPa to 20 MPa, a weight hourly space velocity within a range from 0.1 to 10 kg second reaction section feed per kg catalyst per hour, and a H2 to second reaction section feed ratio within a range from 10 to 2000 normal liters H2 per liter second reaction section feed.

According to a particularly preferred embodiment, the hydroisomerisation in the second reaction section is conducted at a temperature within a range from 230 to 500 °C, a pressure within a range from 2 to 15 MPa, a H2 partial pressure at the inlet of the second reaction section within a range from 2 to 15 MPa, a weight hourly space velocity within a range from 0.2 to 8 kg second reaction section feed per kg catalyst per hour, and a H2 to second reaction section feed ratio within a range from 50 to 1000 normal liters H2 per liter second reaction section feed.

The HI effluent may be subjected to gas-liquid separation, i.e. removal of at least compounds that are gaseous at NTP, before directing the HI effluent to fractionation, e.g. as an integral step within the second reaction section or respective reactor. Separation of gases may also be conducted as part of the fractionation.

Degree of isomerisation of the HI effluent may be increased (improved) by increasing severity of the HI e.g. by at least one or more of: decreasing WHSV, increasing temperature, and/or increasing pressure. When using fresh HI catalyst, high severity HI conditions may be reached at lower temperature and/or pressure, and/or using higher WHSV, and towards the end of the HI catalyst lifetime higher temperature and/or pressure, and/or lower WHSV may be needed to reach even medium severity HI. In the present context, HI that yields, as wt-% of paraffins in the liquid effluent, liquid effluents having total i-paraffins content 50-85 wt-% and multiple-branched i-paraffins content at most 25 wt-%, or total i-paraffins content 85-95 wt-% and multiple-branched i-paraffins content 25-55 wt-%, or total i-paraffins content at least 95 wt-% and multiple-branched i-paraffins content more than 55 wt-%, is generally regarded as HI of low severity, or medium severity, or high severity, respectively, although these content ranges are merely for illustrating the order of magnitude, and may overlap to some extent, and vary from case to case.

In certain preferred embodiments of the present process, the second reaction section feed comprises, in addition to the hydrocracking effluent, a portion of the paraffinic hydrocarbon feed, and the paraffinic hydrocarbon feed is split between the first reaction section feed and the second reaction section feed in a weight ratio within a range from 1 :99 to 99: 1 , preferably from 10:90 to 95:5, more preferably from 20:80 to 90:10, even more preferably from 30:70 to 80:20 first reaction section feed to second reaction section feed. This may be conducted by simply splitting the paraffinic hydrocarbon feed between the first reaction section and the second reaction section, using e.g. a fixed or preferably gradually adjusted ratio. These embodiments provide benefits as explained in the foregoing, for example further flexibility for operating the process, and possibility to adjust the process e.g. according to fluctuations in the characteristics of the paraffinic hydrocarbon feed. Additionally, these embodiments allow operating the process even more precisely in order to meet targeted yields and qualities of more than one recovered component at a time. Furthermore, adjusting the split weight ratio helps to optimize the process according to activity/gradual deactivation of the HI catalyst, for example allowing to incorporate more of the paraffinic hydrocarbon feed in the second reaction section feed in the beginning of the run, and decreasing the paraffinic hydrocarbon feed amount in the second reaction section feed e.g. gradually upon deactivation of the HI catalyst.

Typically, the second reaction section feed comprises at least 30 wt-%, preferably at least 40 wt-%, further preferably at least 50 wt-%, more preferably at least 60 wt-%, further more preferably at least 70 wt-%, even more preferably at least 80 wt-% isoparaffins of the total weight of paraffins in the second reaction section feed; and/or at least 3 wt-% or at least 5 wt-%, preferably at least 10 wt-%, more preferably at least 15 wt-%, even more preferably at least 20 wt-% multiple-branched isoparaffins of the total weight of paraffins in the second reaction section feed.

The HC in the first reaction section efficiently modifies the carbon number distribution of the first reaction section feed, increasing content of hydrocarbons in the aviation fuel range. Hence, in certain preferred embodiments, the weight-ratio of C14-C18 (total) paraffins to C6-C13 (total) paraffins in the second reaction section feed is within a range from 0.6 to 10, preferably from 0.8 to 8.0, more preferably from 0.8 to 7.0, even more preferably from 1.0 to 7.0, further more preferably from 1.1 to 6.0. These ratios provide a good content of aviation fuel range paraffins that are long enough to allow efficient isomerisation, preferably formation of multiple-branched isoparaffins, and short enough so that by efficient isomerisation in the second reaction section they may be recovered from the fractionation as part of the aviation fuel component, improving yield and quality of the aviation fuel component particularly in terms of cold properties.

Preferably, the hydroisomerisation in the second reaction section is operated so that the ratio of the wt-% amount of isoparaffins of the total weight of paraffins in the HI effluent to the wt-% amount of isoparaffins of the total weight of paraffins in the second reaction section feed is at least 2, or at least 4, or at least 6, or at least 8, or at least 10, or at least 12, and/or so that the ratio of the wt-% amount of multiple-branched isoparaffins of the total weight of paraffins in the HI effluent to the wt-% amount of multiple-branched isoparaffins of the total weight of paraffins in the second reaction section feed is at least 2, or at least 4, or at least 6, or at least 8, or at least 10, or at least 12, and/or so that the (total) HI effluent comprises C1-C4 hydrocarbons less than 20 wt-% or less than 10 wt-%, preferably less than 5 wt-%, more preferably less than 3 wt-% of the total weight of the HI effluent. These may be achieved especially when operating the second reaction section within the HI operating conditions and/or using the HI catalyst(s) and/or the second reaction section feed as defined herein.

Typically, the HI effluent comprises at least 60 wt-%, preferably at least 70 wt-%, more preferably at least 80 wt-%, even more preferably at least 90 wt-% or at least 95 wt-% paraffins of the total weight of the HI effluent. In certain embodiment, the HI effluent may even consist essentially of paraffins.

Typically, the HI effluent comprises at least 50 wt-%, preferably at least 60 wt-%, more preferably at least 70 wt-%, even more preferably at least 80 wt-% isoparaffins of the total weight of paraffins in the HI effluent, and optionally multiple-branched isoparaffins at least 5 wt-%, more preferably at least 10 wt-%, even more preferably at least 15 wt-%, or at least 20 wt-% of the total weight of paraffins in the HI effluent.

In certain preferred embodiments, the HI effluent comprises from 50 wt-% to 100 wt-%, preferably from 60 wt-% to 100 wt-%, more preferably from 70 wt-% to 100 wt-%, even more preferably from 80 wt-% to 100 wt-% isoparaffins of the total weight of paraffins in the hydroisomerisation effluent; and/or from 5 wt-% to 75 wt-%, preferably from 10 wt-% to 70 wt-%, more preferably from 15 wt-% to 70 wt-%, even more preferably from 15 wt-% to 65 wt-% multiple-branched isoparaffins of the total weight of paraffins in the HI effluent. This kind of HI effluents are particularly preferred for recovering the liquid transportation fuel component(s) with good yields and/or with high quality, particularly with excellent cold properties, and optionally a recycle stream and/or side cut with high content of isoparaffins, particularly multiple-branched isoparaffins, as may be preferred when incorporating into the first reaction section feed.

Preferably, the first reaction section is operated at a lower temperature than the second reaction section. The temperatures are compared at the inlets of the reaction sections or reactors at a given time point, including short time intervals. In other words, the comparison is not made in this context between the highest temperatures during the whole run from starting the process to stopping it. Embodiments in which the the first reaction section is operated at a lower temperature than the second reaction section have been found particularly beneficial for suppressing aromatizing side reactions or even enhancing dearomatisation in the first reaction section, and for reducing carry-over of aromatics into the second reaction section. As coke-forming compounds, aromatics are foreseen to promote deactivation of the HI catalyst. Additionally, in these embodiments it is possible to start operating the first reaction section in the beginning of the run at a low temperature, using for example lowest feasible temperature in the range specified for hydrocracking, as that provides the widest window for increasing the temperature upon gradual catalyst deactivation, and prolongs the run-time and catalyst change/regeneration intervals.

By operating the first reaction section and the second reaction section within the operating condition ranges specified in the foregoing, and especially when operating the first reaction section at lower temperature than the second reaction section, thermal cracking is controlled, reduced, or minimized in the first reaction section, while a high degree of isomerisation may be reached in the second reaction section, and the content of multiple- branched isoparaffins increased in the HI effluent. At the same time desired degree of effective cracking may be achieved in the first reaction section at milder operating conditions, especially at lower temperature, which improves the yield of hydrocarbons in the aviation fuel boiling range, without excessive thermal cracking leading to gas formation.

The HC catalyst and the hydroisomerisation (HI) catalyst may be arranged in one or more catalyst beds within the first reaction section and second reaction section, respectively. The HC catalyst and the HI catalyst may be arranged in at least one or more fixed beds, respectively. Preferably, the hydrocracking catalyst is arranged in one or more catalyst beds in the first reaction section and the HI catalyst is arranged in one or more catalyst beds in the second reaction section, and the first reaction section and the second reaction section are arranged in the same reactor or in separate reactors, preferably in separate reactors. The HI catalyst may be any conventionally used HI catalyst and the HC catalyst may be any conventionally used HC catalyst. Preferably, the HI catalyst in the second reaction section is a bifunctional HI catalyst, more preferably non-sulphided bifunctional HI catalyst. More preferably, the HI catalyst in the second reaction section and the HC catalyst in the first reaction section are bifunctional HI and HC catalysts respectively, more preferably non- sulphided bifunctional HI and HC catalysts, respectively.

Bifunctional HI and HC catalysts comprise metal sites for catalysing (de)hydrogenation reactions and acid sites for catalysing isomerisation and cracking reactions. Bifunctional HI catalysts and bifunctional HC catalysts are well known in the field of oil refining and in the field of renewable fuel production. Bifunctional HI and HC catalysts are preferred because they have excellent catalytic performance providing synergistic effects between the metal sites and acid sites. Bifunctional HI and HC catalysts are also beneficial as access and diffusion of molecules to catalytic sites may be controlled by suitably selecting porosity characteristics of the catalyst, especially pore size, pore dimension and/or pore interconnectivity in the catalyst.

In certain particularly preferred embodiments, the HI catalyst is a non-sulphided bifunctional hydroisomerisation catalyst and the HC catalyst is a non-sulphided bifunctional hydrocracking catalyst, and said non-sulphided bifunctional catalysts comprise at least one or more metals selected from noble metals of Group VIII, more preferably from Pt and/or Pd, and at least one or more acidic porous materials, and wherein preferably each of the first reaction section feed and the second reaction section feed comprises less than 50 wt- ppm, preferably less than 30 wt-ppm, more preferably less than 10 wt-ppm sulphur (ppm by weight, calculated as elemental S), as determined according to ISO 20846-2019, of the total respective reaction section feed.

The sulphur content may be determined according to ISO 20846-2019 from liquids or according to ASTM-D6667 from gaseous fractions.

Non-sulphided bifunctional catalysts are preferred because they do not require sulphidation during operation for maintaining their activity, and hence the sulphur content of various process streams may be kept low and less efficient H ₂ S separation and recovery is needed from various process streams. Especially non-sulphided bifunctional catalysts comprising noble-metals may be active at lower temperatures and show higher selectivity for isomerisation reactions, compared to sulphided catalysts, but are sensitive to deactivation by H ₂ S. Preferably, the paraffinic hydrocarbon feed comprises sulphur less than 50 wt-ppm, preferably less than 30 wt-ppm, more preferably less than 10 wt-ppm (ppm by weight, calculated as elemental S), as determined according to ISO 20846-2019. A very low sulphur content of the stream entering the first reaction section is beneficial in that only very low amounts or essentially no H ₂ S is formed in the hydrocracking in the first reaction section and hence present in the HC effluent. In such embodiments, gas-liquid separation of the HC effluent before feeding it to the second reaction section is not necessary for protecting the HI catalyst in the second reaction section, but gas-liquid separation of the HC effluent may nevertheless optionally be performed. The overall process may thus be simpler, and liquid transportation fuel component(s) with ultra-low sulphur content are obtainable. Furthermore, since less H ₂ S is present, also less corrosion is foreseen in the long-run, and potentially even less stringent corrosion resistance requirements could be applicable for some of the equipment materials.

Various different kinds of bifunctional HI and HC catalysts are commercially available, for example with different metals or metal combinations, different metal loadings, different add strengths, and/or total acidities, and/or different porosities.

Bifunctional HC catalysts and bifunctional HI catalysts have similarities in the sense that both contain metal sites that are capable of catalysing (de)hydrogenation of n/i-paraffins to corresponding n/i-olefins, and acid sites that are capable of catalysing protonation of the n/i-olefins to n/i-carbocations, isomerisation of n-carbocations, or i-carbocations further, and/or cracking of n/i-carbocations into lighter n/i-olefin and lighter n/i-carbocation, and deprotonation of n/i-carbocations to n/i-olefins. Hydrogenation of the various n/i-olefins is catalysed again by the metal sites of these bifunctional catalysts to form n/i-paraffins. Whether isomerisation or cracking reactions prevail at given operating conditions and given feed composition, may be influenced especially by the characteristics of the bifunctional catalyst to be contacted with the feed. Such characteristics of the bifunctional catalyst include, for example, total acidity of the catalyst, number of Brensted acid sites, strength and/or density of the acid sites, and content of the metal(s) in the catalyst.

Preferably, the bifunctional HI and HC catalysts comprise, independently from each other, at least one or more metals selected from Group VIII of the Periodic Table, preferably from noble metals of Group VIII, more preferably from Pt and/or Pd. Noble metals, particularly in the bifunctional HI catalyst, are preferred as they may provide higher selectivity towards isomerisation reactions under conditions of the second reaction section, and are highly active at lower operating temperatures, compared to catalysts comprising only non-noble metals. High activity at lower temperatures provides a wider temperature range within which temperature may be adjusted, typically increased, during operation. Gradual catalyst deactivation occurring when the process is operated for longer time periods may be compensated to a certain extent by increasing temperature in the reaction section.

Preferably, the bifunctional HI and HC catalysts comprise, independently from each other, at least one or more porous acidic materials having microporous, mesoporous, or hierarchical (micro-mesoporous) structure. Various zeolite-type materials such as SAPOs and zeolites are available providing desired acidity and porosity characteristics.

According to certain embodiments, the hydroisomerisation catalyst is a bifunctional hydroisomerisation catalyst, preferably non-sulphided bifunctional hydroisomerisation catalyst, comprising at least one or more metals selected from Group VIII of the Periodic Table, preferably from noble metals of Group VIII, more preferably from Pt and/or Pd; and at least one or more acidic porous materials selected from zeolites and/or zeolite-type materials, wherein preferably at least one or more of the zeolites and/or zeolite-type materials has a framework type selected from AEL, ATO, AFO, MRE, MTT, MTW, TON, MRT, MOR, PER, and/or MWW, preferably at least one or more acidic porous materials selected from SAPO-11 , SAPO-31 , SAPO-41 , ZSM-22, ZSM-23, ZSM-48, NU-10, ZBM-30, IZM-2, EU-2, and/or mordenite, more preferably at least one or more acidic porous materials selected from SAPO-11 , SAPO-41 , ZSM-23, and/or ZSM-48; and optionally at least one or more of alumina, silica, amorphous silica-alumina, titanium alumina, titania, and/or zirconia.

This catalyst selection has been found to provide high isomerisation selectivity in the second reaction section, achieving even higher amounts of isoparaffins, particularly multiple- branched isoparaffins, in the HI effluent. As a result, n-paraffins present in the second reaction section feed or formed during hydrocracking are efficiently isomerised at least to mono-branched i-paraffins so that high quality liquid fuel components are obtainable with excellent yields. The mentioned SAPOs and zeolites are commercially available with acidity and porosity characteristics that allow isomerisation, including multiple-branching, of n- paraffins, even of long-chained n-paraffins, such as C16+ paraffins.

Particularly for the hydrocracking reactions in the first reaction section of the present process, bifunctional HC catalysts are beneficial because they have in addition to cracking activity also some isomerisation activity, and may be especially efficient in effective cracking. As further advantage, bifunctional HC catalysts comprising at least one or more metals selected from Group VIII noble metals, preferably from Pt and/or Pd have been found to provide at relatively low temperatures a high activity, compared to HC catalysts comprising non-noble metals, and thus even better control of thermal cracking. At low temperatures, the thermodynamic equilibrium tends to shift towards dearomatisation, thus reducing aromatics formation by side reactions. Providing the first reaction section with a bifunctional HC catalyst may achieve an isoparaffin content (wt-% isoparaffins of the total weight of paraffins) in the hydrocracking effluent that is not necessarily significantly lower than in the first reaction section feed, or may be the same, or even higher.

Hence, according to certain embodiments, the hydrocracking catalyst is a bifunctional hydrocracking catalyst, preferably a non-sulphided bifunctional hydrocracking catalyst, comprising at least one or more metals selected from Group VIII of the Periodic Table, Mo, Co and/or W, preferably from Ni, Mo, Co, W, Pt, and/or Pd, more preferably from Pt and/or Pd; and at least one or more acidic porous materials selected from zeolites, zeolite-type materials and/or amorphous silica-alumina, wherein preferably at least one or more of the zeolites or zeolite-type materials has a framework type selected from MFI, BEA, FAU, MOR, FER, AEL, AFI, ATO, AFO, MRE, MTT, MTW, TON, and/or MRT, preferably at least one or more acidic porous materials selected from SAPO-5, SAPO-11 , SAPO-31 , SAPO-41 , ZSM- 22, ZSM-23, ZSM-43, ZSM-48, IZM-2, mordenite, beta-zeolites, Y-type zeolites, and/or amorphous silica-alumina, more preferably at least one or more acidic porous material selected from SAPO-5, SAPO-11, ZSM-23, beta-zeolites, Y-type zeolites, and/or amorphous silica-alumina; and optionally at least one or more of alumina, silica, titanium alumina, titania, and/or zirconia.

In certain embodiments the HC catalyst in the first reaction section and the HI catalyst in the second reaction section have different acidity-related characteristics. The acidity-related characteristics of acidic porous materials, such as zeolite, may include nature, number, and distribution, according to relative strength, of acid sites, and may be determined by well- known methods, for example by adsorption-desorption methods where release of adsorbed base substance like ammonia or pyridine at higher temperature indicates presence of strong acid sites. As one example of usable adsorption-desorption methods, a temperature programmed desorption of ammonia can be mentioned, for examples as performed in accordance with the procedure described in Niwa et al (Niwa, M., Katada, N. Measurements of acidic property of zeolites by temperature programmed desorption of ammonia. Catalysis Surveys from Asia 1 , 215-226 (1997)). Yet another well-known method for determining the acidic property of zeolites, including strength of acidity, is ¹ H-NMR method, for examples as performed in accordance with the procedure described in Heeribout et al (Heeribout L., Semmer V., Batamack P., Dorémieux-Morin C., Fraissard J. Brensted acid strength of zeolites studied by ¹ H NMR: scaling, influence of defects. Microporous and Mesoporous Materials, Volume 21, Issues 4-6, May 1998, Pages 565-570). In certain preferred embodiments, the bifunctional HC catalyst in the first reaction section has a higher number of Brensted acid sites compared to the bifonctional HI catalyst in the second reaction section, as determined by NH ₃ -TPD. In certain preferred embodiments, the bifonctional HC catalyst in the first reaction section has a higher total number of acid sites compared to the bifonctional HI catalyst in the second reaction section, as determined by NH ₃ -TPD.

In certain preferred embodiments, the bifonctional HC catalyst of the first reaction section has a higher content (wt-%) of Group VIII noble metal(s) compared to the bifonctional HI catalyst of the second reaction section. In these embodiments as good or better yields of aviation fuel component can be achieved at lower temperature, compared to otherwise similar process but using bifonctional HC catalyst that does not have a higher content of said noble metal(s) compared to the bifonctional HI catalyst.

In the present process, a first reaction section feed comprising a paraffinic hydrocarbon feed is subjected to HC in the presence of a HC catalyst, and a HC effluent and optionally a portion of the paraffinic hydrocarbon feed are subjected to HI in the presence of a HI catalyst. The HI catalyst and the HC catalyst may have similar or same components. According to a preferred embodiment, the HI catalyst and the HC catalyst are different from each other. The HI catalyst and the HC catalysts may differ from each other for example by selection of at least one or more of catalyst components, acidity, and/or metal loading, just to name a few. However, when conducting the hydrocracking and the HI in separate reactors, it is also possible to use same catalyst as the HC catalyst in the first reaction section and as the HI catalyst in the second reaction section. Not only the catalyst but also the operating conditions and the composition of the reaction section feed contribute to which reactions prevail. For example, when contacting the first reaction section feed with the HC catalyst under the hydrocracking conditions, more cracking can be expected compared to contacting the second reaction section feed with the HI catalyst under the HI conditions, even if the catalysts were the same. Preferably, when contacting the second reaction section feed with the HI catalyst under the HI conditions, isomerisation of this feed prevails over cracking.

The HI catalyst and the HC catalyst may be in ready-to-use state as such or they may be as treated in any customary way to adjust their properties, such as selectivity and/or activity, before or during start-up by subjecting to reduction, sulphidation, and/or passivation for example with a nitrogen containing compound, such as an amine or ammonia, so as to obtain the ready-to-use fresh or regenerated HI catalyst and/or HC catalyst. As used herein, HI catalyst, HC catalyst, fresh catalyst, and regenerated catalyst generally refer to the catalyst in its ready-to-use state.

The HI catalyst in the optional initial hydroisomerisation, and the HI catalyst in the second reaction section may have different characteristics and/or composition, or may have same characteristics and compositions, i.e. they may be different catalysts or same catalysts. For process simplicity it is preferred that the HI catalyst in the optional initial hydroisomerisation is the same catalyst as the HI catalyst in the second reaction section, in which case the HC catalyst is preferably different from the HI catalyst in the initial HI and in the second reaction section.

In certain embodiments, a weight ratio of the hydrocracking catalyst in the first reaction section to the hydroisomerisation catalyst in the second reaction section is within a range from 5:95 to 70:30, preferably from 10:90 to 65:35, more preferably from 20:80 to 60:40. Such ratios are beneficial in that they enable a high isomerisation degree of the recovered liquid transportation fuel component(s), typically improving the cold properties of the recovered liquid transportation fuel component(s), especially the cold properties of aviation fuel component and/or diesel fuel component, and/or RON of gasoline fuel component. Also, said HC catalyst to HI catalyst ratios are beneficial in that they allow to more freely select the HC catalyst in the first reaction section.

It is well known to a skilled person how to select the HC and HI conditions, preferably within the HC and the HI condition ranges specified in the foregoing, taking into account the selected HC catalyst, composition of the first reaction section feed, and targeted degree of effective cracking, as well as targeted degree of isomerisation; and taking into account the selected HI catalyst, composition of the second reaction section feed, targeted degree of isomerisation, and targeted content of multiple-branched isoparaffins in the effluent of the second reaction section. To a certain extent, catalyst age or catalyst deactivation may also be taken into account when selecting or adjusting operating conditions of the first reaction section and/or the second reaction section. During continued operation, the HC catalyst and the HI catalyst deactivate gradually for example due to impurities in process streams and coking. As the catalyst(s) deactivate, catalyst activity is reduced and selectivity affected, and at some point desired properties of the HC effluent and/or the HI effluent are typically no longer reached. Also, changes in the paraffinic hydrocarbon feed composition during the run may lead to deviation from the desired properties and/or yields of the recovered liquid transportation fuel component(s). Additionally, the targeted product slate and qualities may vary depending on market demand and seasonal variation.

The present process involves various possibilities to tackle the above-mentioned challenges due to the set-up, i.e. conducting hydrocracking before hydroisomerisation followed by recovery of the liquid transportation fuel component(s) from the fractionation, with the possibility to split the paraffinic hydrocarbon feed between the first reaction section and the second reaction sections, and with the possibility to recover recycle stream and/or side cut from the fractionation and to feed them back to the hydrocracking. Preferably, the present process comprises monitoring at least one or more parameters, typically indicative of deactivation of the HC and/or HI catalyst, to receive at least one or more values, comparing the received value(s) with predetermined value(s) and based on the comparison utilising at least one of the various adjustment possibilities of the process.

Hence, according to certain preferred embodiments, the process further comprises monitoring to receive at least one or more values at least one or more of the following parameters:

- content of an impurity in the paraffinic hydrocarbon feed, preferably content of at least one or more of N, S, O, P, Si, Cl, Fe, alkali metals, alkaline earth metals, and/or cokeforming compounds in the paraffinic hydrocarbon feed; Said species or impurities are known catalyst deactivators, particularly deactivators of non-sulphided bifunctional catalysts comprising noble metal(s). Also, said species or impurities are commonly present in varying amounts in feeds derived from vegetable oils, animal fats, microbial oils, thermally and/or enzymatically liquefied organic waste and residues, as well as in feeds derived from Fischer-Tropsch process, and may hence in certain embodiments be carried-over in varying amounts to and be present in the paraffinic hydrocarbon feed. Typically, the elemental impurities are not present as such in the paraffinic hydrocarbon feed but contents thereof indicate presence of compounds comprising said impurities. Elemental impurities and cokeforming compounds are determined by standard laboratory analyses. Increased content of any of these impurities may lead to increased catalyst deactivation.

- content of NH ₃ and/or H ₂ S in the gaseous phase of the hydrocracking effluent and/or NH3 and/or H ₂ S in the gaseous phase of the HI effluent; In some cases, increased content of NH ₃ and/or H ₂ S in the gaseous phase of the HC effluent could indicate increased catalyst exposure to said impurities. Increased content of any of these impurities may lead to increased catalyst deactivation.

- physico-chemical characteristics of the paraffinic hydrocarbon feed, of the first reaction section feed, of the hydrocracking effluent, of the second reaction section feed, and/or of the hydroisomerisation effluent, preferably at least one or more of a cloud point, freezing point, pour point, cold filter plugging point, kinematic viscosity, density, and/or a distillation characteristic; Increase in any of cloud point, freezing point, pour point, cold filter plugging point, kinematic viscosity, and/or density, may indicate increased catalyst deactivation. Distillation characteristics, wherein an increase may be indicative of catalyst deactivation comprise T5, T50, EBP etc. As to further distillation characteristics, a shift of boiling point distribution to higher boiling compounds, may be indicative of catalyst deactivation. To some extent the physico-chemical characteristics may be indicative of or correlate with the content of isoparaffins or multiple-branched isoparaffins in the paraffinic hydrocarbon feed, the first reaction section feed, the hydrocracking effluent, the second reaction section feed, and/or the hydroisomerisation effluent.

- compositional characteristics of the paraffinic hydrocarbon feed, of the first reaction section feed, of the hydrocracking effluent, of the second reaction section feed, and/or of the hydroisomerisation effluent, preferably at least one or more of content of isoparaffins, content of C8-C14 hydrocarbons, content of multiple-branched isoparaffins, content of n- paraffins, and/or content of C1-C4 hydrocarbons in the hydrocracking effluent and/or in the hydroisomerisation effluent; Decrease in content of isoparaffins, multiple-branched isoparaffins, and C8-C14 hydrocarbons may indicate increased catalyst deactivation. To some extent the content of isoparaffins or multiple-branched isoparaffins may be indicative of or correlate with the physico-chemical characteristics of the paraffinic hydrocarbon feed, of the first reaction section feed, of the hydrocracking effluent, of the second reaction section feed, and/or of the hydroisomerisation effluent. Content of C1-C4 decreases along with increased catalyst deactivation. However, increasing operating temperature to compensate for catalyst deactivation may lead to increase in C1-C4 content in respective effluent.

- yield of at least one or more of the recovered liquid transportation fuel components, of the optionally recovered recycle stream, and/or of the optionally recovered side cut, preferably at least yield of recovered aviation fuel component(s); Increased yield of higher boiling hydrocarbons and increased volume of the optionally recovered recycle stream may indicate increased catalyst deactivation.

- physico-chemical characteristics of at least one or more of recovered liquid transportation fuel components, of the optionally recovered recycle stream, and/or of the optionally recovered side cut, preferably at least one or more of a cloud point, freezing point, pour point, cold filter plugging point, kinematic viscosity, density, research octane number (RON), cetane number, and/or a distillation characteristic; A decrease in cetane may indicate increased catalyst deactivation. Among distillation characteristics, an increase e.g. in T5, T50, T95 EBP or a shift of boiling point distribution to higher boiling compounds may be indicative of catalyst deactivation. To some extent the physico-chemical characteristics may be indicative of or correlate with the content of isoparaffins or multiple-branched isoparaffins in the recovered liquid transportation fuel component(s) and/or the optionally recovered recycle stream and/or side cut.

- compositional characteristics of at least one or more of the recovered liquid transportation fuel components, of the optionally recovered recycle stream, and/or of the optionally recovered side cut, preferably content of isoparaffins and/or content of multiple- branched isoparaffins and/or content of n-paraffins; Decrease in content of isoparaffins, multiple-branched isoparaffins, and/or C8-C14 hydrocarbons may indicate increased catalyst deactivation. To some extent the content of isoparaffins or multiple-branched isoparaffins may be indicative of or correlate with the physico-chemical characteristics of the recovered liquid transportation fuel component(s) and/or the optionally recovered recycle stream and/or side cut.

- and/or temperature difference over the first reaction section or a catalyst bed therein and/or over the second reaction section or a catalyst bed therein; Said temperature differences are relatively easy to monitor, and a decrease of the temperature difference may be a typical sign of catalyst deactivation. the process comprising comparing the received value(s) with predetermined value(s) and based on the comparison; adjusting the weight ratio of the paraffinic hydrocarbon feed to a sum amount of the recycle stream and/or the side cut in the first reaction section feed; adjusting the split weight ratio of the paraffinic hydrocarbon feed fed to the first reaction section as part of the first reaction section feed and to the second reaction section as part of the second reaction section feed; and/or adjusting at least one or more operating conditions in the first reaction section and/or in the second reaction section, preferably adjusting at least one or more of temperature, pressure, weight hourly space velocity (WHSV), H2 to first reaction section feed ratio, H2 to second reaction section feed ratio, and/or H2 partial pressure at the inlet of the first reaction section and/or the second reaction section, respectively, more preferably increasing the temperature and/or the pressure in the first reaction section and/or in the second reaction section and/or decreasing the WHSV in the first reaction section and/or in the second reaction section, respectively.

Different parameters may be monitored and/or different predetermined values selected during the process, for example depending on changes in the targeted product slate and qualities. In certain preferred embodiments, the process comprises monitoring at least two, or at least three of the above-mentioned parameters, typically indicative of deactivation of the HC catalyst and/or HI catalyst. For example, good cold properties (e.g. doud point, pour point, subzero viscosity) of the HI effluent may be achieved due to increased amount of shorter carbon chains caused by increased cracking taking place (caused e.g. by increased temperature), instead of sufficient degree of isomerisation. Thus, it may be beneficial to monitor at least two or three or even more parameters in order to obtain better understanding on the status of the catalyst deactivation. The monitoring may be performed continuously, repeatedly, continually, periodically, intermittently, discontinuously, as onetime monitoring, on-line, or off-line.

Once the operating conditions in the first and/or in the second reaction section have been adjusted to their feasible extremes, preferably within the hydrocracking or hydroisomerisation condition ranges, respectively, as specified in the foregoing, the catalyst(s) need to be changed to fresh one(s) or regenerated, in order to be able to reach the targeted product slate and quality of the recovered liquid transportation product(s) again. The present process facilitates prolonging the run-time and catalyst change/regeneration intervals.

The present process comprises fractionation in which at least one or more liquid transportation fuel components, and optionally a recycle stream and/or a side cut, are recovered. The amount of recycle stream and/or side cut separated and the amount of recycle stream and/or side cut fed to the first reaction section may vary within broad ranges, as discussed in connection with the recycle stream and the side cut, respectively. Further liquid streams or cuts, such as further side cut(s), may optionally be recovered from the fractionation and optionally recycled back to the process.

The fractionation of the present process may comprise any conventionally used fractionation technology. Preferably, the fractionation comprises distillation, such as atmospheric distillation or vacuum distillation, optionally preceded by a gas-liquid separation e.g. as described hereinafter. The fractionation may be carried out in a fractionation system comprising one or more fractionation units. For example, gases and light naphtha may be separated in a pre-fractionation unit, while the liquid transportation fuel component(s) and optionally the recycle stream and/or the side cut are recovered from a main distillation unit downstream of the pre-fractionation unit. In an alternative example, a single fractionation unit may be used.

The HI effluent may be subjected to gas-liquid separation for example as an integral step within the respective reactor, or within the fractionation system. Typically, the gas-liquid separation is conducted at a temperature within a range from 0 °C to 500 °C, such as from 15 °C to 300°C, or from 15 °C to 150 °C, preferably from 15 °C to 65 °C, such as from 20 °C to 60 °C, and preferably at the same pressure as that of the reactor wherefrom the effluent originates. Typically, the pressure during the gas-liquid separation(s) may be within a range from 0.1 MPa to 20 MPa, preferably from 1 MPa to 10 MPa, or from 3 MPa to 7 MPa. The conditions may apply to any gas-liquid separation conducted in the present process.

According to embodiments of the present process, different products as liquid transportation fuel components may be recovered from the fractionation depending e.g. on the operating conditions chosen, composition of the used paraffinic feed, and/or market demand at a given time.

As shown in the Examples, with the present process it is possible to produce at least an aviation fuel component and a diesel fuel component, both with as good as or improved cold properties, and with surprisingly high combined yield of the aviation and diesel fuel components, compared to a process using only HI, only HC, or HI followed by HC, before fractionation and product recovery.

Hence, in preferred embodiments of the present process, at least one of the liquid transportation fuel components recovered from the fractionation is an aviation fuel component having density at 15 °C within a range from 730 kg/m ³ to 772 kg/m ³ (EN ISO 12185-1996). T10 temperature at most 205 °C (EN ISO 3405-2019), final boiling point at most 300 °C (EN ISO 3405-2019), flash point at least 38 °C (IP 170-2013, Abel closed-cup method) and freezing point at most -40 °C (IP 529-2016). In these embodiments the recovered aviation fuel component is of high quality, and can be incorporated in aviation fuel compositions in elevated amounts. Typically, the aviation fuel component has T10 and T90 temperatures, as determined according to EN ISO 3405-2019, within a range from 120 °C to 295 °C, preferably within a range from 130 °C to 295°C.

The present process enables recovery of at least an aviation fuel component in surprisingly high yields, even towards the end of the HI catalyst lifecycle. In certain preferred embodiments of the present process, the aviation fuel component is recovered in a yield of at least 30 wt-%, preferably at least 40 wt-%, more preferably at least 50 wt-%, such as from 30 wt-% to 90 wt-% of the total weight of the paraffinic hydrocarbon feed. This is believed to be enabled by a high content of C8-C14 hydrocarbons and isoparaffins in the feed subjected to fractionation, of which a notable share is multiple-branched isoparaffins. Typically, in the present process at least one or more of an aviation fuel component, a diesel fuel component, a gasoline fuel component, and/or a marine fuel component is recovered from the fractionation, preferably at least an aviation fuel component, more preferably at least an aviation fuel component and a diesel fuel component, even more preferably at least an aviation fuel component, a diesel fuel component and a gasoline fuel component, are recovered from the fractionation. In embodiments involving recovering and hydrocracking of the recycle stream, it is generally preferred to recover from the fractionation at least periodically at least one heavy product such as a diesel fuel component, marine fuel component, transformer oil component, and/or a base oil component to avoid accumulation of the heaviest components in the recycle loop.

In preferred embodiments, the recovered liquid transportation fuel component(s) have a biogenic carbon content (EN 16640 (2017)) of at least 50 wt-%, preferably at least 70 wt- %, more preferably at least 90 wt-%, even more preferably at least 95 wt-%, or even about 100 wt-%, based on the total weight of carbon (TC) in the respective recovered liquid transportation fuel component. The biogenic carbon content in the recovered liquid transportation fuel component(s) is mainly influenced by the biogenic carbon content in the paraffinic hydrocarbon feed, in preferred embodiments by the oxygenated hydrocarbon feed subjected to HDO followed optionally by initial HI. There is a strong demand in the field for hydrocarbon components with increased bio-content for a wide variety of end-uses.

Schematic presentation of the process

Figures 1 and 2 schematically show processes according to example embodiments. In Figs. 1 and 2, oxygenated hydrocarbon feed 510 is fed to a HDO reactor 520 in which it is subjected to hydrodeoxygenation in the presence of a HDO catalyst 530 to obtain a hydrodeoxygenation effluent (HDO effluent) 540, and the obtained HDO effluent 540 is subjected to gas-liquid separation 550 to separate from the HDO effluent at least compounds that are gaseous at NTP 560 to obtain a degassed HDO effluent 570. The degassed HDO effluent 570 is in Figs. 1 and 2 then fed to an initial hydroisomerisation reactor 580 in which the degassed HDO effluent 570 is subjected to initial hydroisomerisation in the presence of an initial HI catalyst 590 to obtain a paraffinic hydrotreatment effluent 600, and the obtained paraffinic hydrotreatment effluent 600 is subjected to gas-liquid separation 610 to separate from the paraffinic hydrotreatment effluent 600 at least compounds that are gaseous at NTP 620 to obtain a degassed paraffinic hydrotreatment effluent 630, which is in these example embodiments the paraffinic hydrocarbon feed as herein defined. Figs. 1 and 2 show the possibility to split a portion 650 from the paraffinic hydrocarbon feed 630, and to feed the split portion 650 to the second reaction section 740 . In Figs. 1 and 2 a first reaction section feed 660 comprising the paraffinic hydrocarbon feed 630 (or 640 if the portion 650 was split therefrom) is then fed to a first reaction section 670 in which the first reaction section feed 660 is subjected to hydrocracking in the presence of a hydrocracking catalyst 680 to obtain a hydrocracking effluent (690 in Fig. 2). In Fig. 1 the first reaction section 670 comprising the HC catalyst 680 and the second reaction section 740 comprising the HI catalyst 750 are arranged in the same reactor, and in Fig 2 in separate reactors. Thus Fig. 2 shows the possibility to subject the hydrocracking effluent 690 to gas-liquid separation 700 to separate from the hydrocracking effluent 690 at least compounds that are gaseous at NTP 710 to obtain a degassed hydrocracking effluent 720. In Fig. 2, the hydrocracking effluent 690 or degassed HC effluent 720, optionally combined with the portion 650 split from the paraffinic hydrocarbon feed 630, as the second reaction section feed (730 in Fig 2) is then subjected in the second reaction section 740 to HI in the presence of a HI catalyst 750 to obtain a HI effluent 760, and the obtained HI effluent 760 is subjected to gas-liquid separation 770 to separate from the HI effluent 760 at least compounds that are gaseous at NTP 780 to obtain a degassed HI effluent 790. The degassed HI effluent 790 is then in Figs. 1 and 2 fed to a distillation unit 800, that may comprise a single column, or prefractionation and main distillation columns, from which several streams or cuts are obtained. In Figs. 1 and 2, from the distillation, a gasoline fuel component 810, an aviation fuel component 820, and/or a diesel fuel component 830, and optionally a recycle stream 840, are recovered. The optionally recovered recycle stream 840 may be fed to the first reaction section 670 as part of the first reaction section feed 660.

Fig. 3 presents distillation curves, i.e. temperature as a function of recovered distillate (weight-%), as determined according to ASTM D2887-19e1, for the degassed effluents (liquid products) from a test run according to an example embodiment of the present process, TR4b_INV, i.e. using a catalyst system HC-HI, and from three comparative test runs TR1b using only HI catalyst, TR2b using a catalyst system HI-HC, and TR3b using only HC catalyst. The test run conditions for obtaining the degassed test run effluents are disclosed and results discussed in Example 1.

Fig. 4 schematically shows an illustrative process involving hydrocracking. This process was used in Example 2, as HC process 1. In Fig.4, oxygenated hydrocarbon feed 110 is fed to a H DO reactor 120 in which it is subjected to hydrodeoxygenation in the presence of a HDO catalyst 130 to obtain a hydrodeoxygenation effluent (HDO effluent) 140, and the obtained HDO effluent 140 is subjected to gas-liquid separation 150 to separate from the HDO effluent at least compounds that are gaseous at NTP 160 to obtain a degassed HDO effluent 170. The degassed HDO effluent 170 is in Fig. 4 then fed to a first reactor 180 in which the degassed HDO effluent 170 is subjected to hydroisomerisation in the presence of a HI catalyst 190 to obtain a HI effluent 200, and the obtained HI effluent 200 is subjected to gas-liquid separation 210 to separate from the HI effluent 200 at least compounds that are gaseous at NTP 220 to obtain a degassed HI effluent 230. In Fig. 4, the degassed HI effluent 230 is fed to a distillation unit 240, that may comprise a single column, or prefractionation and main distillation columns, from which several streams or cuts are obtained. From the distillation in Fig. 4, a gasoline fuel component 250, an aviation fuel component 260, and/or a diesel fuel component 270 are recovered, and further, a recycle stream 280 having a T5 boiling point of 270 °C or higher is separated. The recycle stream 280 is in Fig. 4 fed to a second reactor 290 in which it is subjected to hydrocracking in the presence of a HC catalyst 300 to obtain a recycle effluent 310. In Fig. 4, the recycle effluent 310 is subjected to gas-liquid separation 320 to separate from the recycle effluent 310 at least compounds that are gaseous at NTP 330 to obtain a degassed recycle effluent 340, and the degassed recycle effluent 340 is then fed as a co-feed with the degassed HI effluent 230 to the distillation unit 240 for fractionation. In certain embodiments a portion of the HI effluent 200, 230 may be fed as a co-feed 500 with the recycle stream 280 to hydrocracking in the second reactor 290. Contrary to Fig 4, the HC process 1 in Example 2 did not feed a portion of the HI effluent 200, 230 as a co-feed 500 with the recycle stream 280 to the hydrocracking reactor 290.

Fig. 5 schematically shows another illustrative process involving hydrocracking. This process was used in Example 2, as HC process 2, without the recycle feed. In Fig. 5, the process proceeds as in Fig 4 to obtain a degassed HI effluent 230. In Fig. 5, the degassed HI effluent 230 is fed to a second reactor 290 in which it is subjected to hydrocracking in the presence of a HC catalyst 300 to obtain a hydrocracking effluent 350, and the hydrocracking effluent 350 is subjected to gas-liquid separation 360 to separate from the hydrocracking effluent 350 at least compounds that are gaseous at NTP 370 to obtain a degassed hydrocracking effluent 380. In Fig. 5, the degassed hydrocracking effluent 380 is fed to a distillation unit 240, that may comprise a single column, or prefractionation and main distillation columns, where it is fractionated into several streams or cuts. From the distillation in Fig. 5, a gasoline fuel component 390, an aviation feel component 400, and a diesel feel component 410 are recovered. Contrary to Fig 5, the HC process 2 in Example 2 did not separate and hydrocrack a recycle stream 420, nor feed a portion of the HI effluent 200 or 230 as a co-feed 500 with the hydrocracking effluent 350, 380 to the fractionation 240. EXAMPLES

Example 1 - Test runs

Two different test run feeds (Feed A and Feed E) were obtained by subjecting a fatty feedstock to hydrodeoxygenation (HDO) and gas-liquid separation to obtain paraffinic feed comprising >95 wt-% paraffins of the total weight of the paraffinic feed, and subjecting the paraffinic feed to an initial hydroisomerisation (HI) of low severity (Feed A) or medium severity (Feed E). Fractions of the effluents from the initial HI were obtained by recovering therefrom just a bottom fraction (Feed A), or by degassing and stabilising to remove gases and light naphtha (Feed E). Details of these feeds A and E are reported in Table 1.

Table 1. Details of the test run feeds. In the test runs the heavier Feed A and lighter Feed E were subjected according to the present process to hydrocracking (HC) using HC catalyst (1.7 g) followed by HI using HI catalyst (1.7 g), and for comparison just to hydroisomerisation using HI catalyst (3.4 g), just to hydrocracking using HC catalyst (3.4 g), and to HI using HI catalyst (1.7 g) followed by hydrocracking using HC catalyst (1.7 g). Whether the catalysts in the test runs were only HI, only HC, HI followed by HC, or HC followed by HI, the total/cumulative catalyst amount per test run was the same. One HI catalyst and one HC catalyst were used in the test runs, both were non-sulphided bifunctional catalysts. In Table 2 test run conditions and catalysts are reported, as well as cloud points measured for the degassed test run effluents (liquid products).

Table 2. Process details for test run conditions, catalysts, and time on stream. In each of the test runs the total amount of catalyst(s) was the same (3.4g), WHSV was 1.5 1/h, pressure 40 bar, H2 to liquid feed ratio 500 nL/L.

From Table 2 it can be seen that with each of the tested catalyst systems increasing the reaction temperature yielded liquid effluent with lower (better) cloud points. When comparing test runs TR3a-c using only HC catalyst and fed with feed A, to test runs TR1a- c using only HI catalyst and fed with feed A, it can be seen that with HC catalyst clearly lower operating temperatures sufficed to reach the same level of cloud point, representing cold properties of the test run effluents as degassed (i.e. liquid test run products).

An interesting comparison can be made between test runs TR1a using HI catalyst at 300 °C, TR2a using HI-HC catalysts at 300 °C/300 °C, TR3a using HC catalyst at 290 °C, and TR4a_INV according to the present process using HC-HI catalysts at 290 °C/290 °C, each of these test runs fed with the heavier feed A. Using the same total catalyst amount and very similar operating conditions, the present process provided lowest cloud point, -31.4 °C, which is about 8 °C lower than the cloud point provided by TR1a using HI catalyst, -23.2°C, and than the cloud point provided by TR2a using HI-HC catalysts, -23.8°C. The improvement in cloud point provided by the present process was about 6 °C, compared to TR3a using HC catalyst, -25.8°C, which provided the second lowest cloud point of these test runs.

Distillation temperatures as a function of recovered distillate (weight-%) are presented in Fig 3 for test runs TR1b (HI only), TR2b (HI-HC), TR3b (HC only) and TR4b_INV (HC-HI). Even though TR4b_INV had of these test runs the lowest cloud point (-34.8 °C), for example the temperature at which 10 weight-% had been recovered was the highest. TR1b (HI only) and TR3b (HC only) had quite similar distillation curves in the beginning, but at about 60 weight-% recovered, TR3b started to have higher temperatures than the other test runs, which might explain why TR3b’s cloud point was only -16.7°C. In the end TR1b (HI only) exhibited a noticeable heavy tail, possibly affecting the cloud point, which was only -23.8°C for TR1b. TR2b (HI-HC) on the other hand had lowest temperatures throughout the distillation. Based on the distillation curves alone one might have expected TR2b (HI-HC) to exhibit lowest cloud point of the test runs in Fig. 3, but surprisingly cloud point of TR2b was only second lowest, -28.5°C, while doud point of TR4b_INV was remarkably lower, - 34.8°C. These results illustrate the importance of HC catalyst being followed by HI catalyst, and not vice versa, in order to reach the enhanced cold properties.

Comparison of test runs TR5-TR8 fed with the lighter feed E is less straightforward due to differences in test run temperatures. Nevertheless, here the test runs TR8a_INV and TR8b_INV according to the present process provided approximately equally excellent cloud points with test runs TR5a and TR5b using only HI catalyst. With the lighter feed E, the least performing test runs in terms of achieved cloud points were TR3a and TR3b using only HC catalyst. When comparing TR1-TR4 test run results to TR5-TR8 test run results, obtained using the same catalyst set-ups at similar temperatures, different behaviour in terms of achieved cloud points can be seen. These are most likely due to the differences in the feed properties: Feed A is much heavier, having C17+ content of about 97 wt-% compared to C17+ about 60 wt-% of Feed E, but Feed A has also lower isomerisation degree particularly in terms of content of multiple-branched i-paraffins, this value being about 20 wt-% for Feed A and about 50 wt-% for Feed E.

Degassed test run effluents were fractionated to recover a gasoline fuel component, an aviation fuel component, and a diesel fuel component. Yields of these liquid fuel components, ratios of aviation fuel component yield to diesel fuel component yield and vice versa, as well as yields of the C1-C4 gaseous fraction are reported in Table 3. Also, some physico-chemical properties of the diesel and aviation fuel components were measured and are reported in Table 4.

Table 3. For selected test runs yields (as wt-% of hydrocarbons in the test run effluents) of C1-C4 gaseous fraction, gasoline fuel component (GFC), aviation fuel component (AFC), and diesel fuel component (DEC), as well as total yield of AFC and DEC are presented. Also, ratios of AFC to DEC, and of DEC to AFC are presented.

Table 4. For selected test runs cloud points of the diesel fuel components (DEC) and aviation fuel components (AFC), as well as flash point and density at 15 °C of the aviation fuel component.

From Table 3 it can be seen that the test runs according to the present process produced lowest amount of light gases, with both the heavier feed A and the lighter feed E, about half the amount compared to test runs with only HI. Also, the combined yield of the aviation fuel component and the diesel fuel component, that are in the present context considered the most valuable products from the process, was highest in the test runs according to the present process, and surprisingly lowest in the test runs using HI-HC, i.e. same catalysts as in the present process but in the opposite order. Interestingly the feed composition did not seem to have much influence on the yield of light gases and combined yield of diesel and aviation fuel components, but in test runs fed with the heavier feed A the share of produced diesel fuel component increased, although aviation fuel component still remained as the main product. In the test runs according to the present process, the heavier Feed A having lower content of multiple-branched i-paraffins provided the greatest share of the produced diesel fuel component. In other words, with the present process it seems possible to produce a higher share of diesel fuel component compared to the other test run set-ups, simply by increasing the heaviness and/or reducing the content of multiple-branched i- paraffins of the first reaction section feed. This could be achieved for example by incorporating to the first reaction section feed a recycle stream or side-cut from the fractionation. This provides a valuable and simple means for adjusting the shares of the produced diesel and aviation fuel components, for example responding to fluctuations in the market demand of these products.

From Table 4 it can be seen that the diesel fuel component obtained from the test runs according to the present process had best cold properties as evident from the lowest cloud points, and the doud points of the aviation fuel component were second lowest, only slightly higher compared to aviation fuel components from the test runs using only HI. However, producing the aviation fuel component by process using only HI has the drawback of highest light gas formation, as can be seen from Table 3. The densities of the aviation fuel components from the test runs according to the present process were above the upper limit 772 kg/m ³ set in ASTM D7566-21 Annex A2 for isoparaffinic kerosene obtained from hydroprocessed fatty feedstocks, but on the other hand the flash points were well above the minimum value 38 °C set in ASTM D7566-21 Annex A2, so the density could be easily adjusted to meet the requirement by optimizing or adjusting the distillation cut-offs and recovering more of the light end to the aviation fuel component. Example 2 - Simulations 1

Simulations were carried out using Aspen Plus V10.0 software for illustrating benefits of the present process compared to a conventional HVO process where fatty feedstock is subjected to a hydrodeoxygenation (HDO) step and subsequent HI step (herein referred to as initial HI), as disclosed e.g. in Fl 100248 and EP1396531, followed by fractionation to recover at least an aviation fuel component.

The oxygenated hydrocarbon feed fed to HDO comprised 100% animal fat, and the highly paraffinic feed (comprising about 98 wt-% paraffins) fed to the initial HI comprised about 59 wt-% C17-C18 n-paraffins, about 29 wt-% C15-C16 n-paraffins, about 4 wt-% C17-C18 isoparaffins and about 2 wt-% C15-C16 isoparaffins. About 97 wt-% of the paraffinic feed fed to the initial HI was C14-C22 hydrocarbons, and about 1 wt-% was cyclic hydrocarbons.

Reference 1 (Tables 5 and 6) shows a typical product distribution recovered from fractionation of a conventional HVO process run in winter grade renewable diesel production mode, i.e. involving a HDO step followed by a medium severity HI step. Reference 2 (Tables 5 and 6) shows a typical product distribution recovered from fractionation of a HVO process run with a similar HDO step than Reference 1 but followed by a high severity HI step using a fresh catalyst.

For the HC process 1 (Tables 5 and 6) the process presented in Fig. 4 was used, with HDO and initial HI steps run similarly as for Reference 1 , followed by fractionating the initial HI effluent and a hydrocracking effluent coming from hydrocracking reactor fed with a recycle stream (portion of the diesel component recovered from the fractionation). For the HC process 2 (Tables 5 and 6) the process presented in Fig. 5 was used (without a recycle stream), with HDO and initial HI steps run similarly as for Reference 1, followed by hydrocracking of the initial HI effluent, and fractionation.

Components shown in Table 5 were recovered from fractionation. Tables 5 and 6 show that compared to the process of Reference 2, the HC process 2 provided similar, very good sustainable/renewable aviation fuel (SAF) component and winter grade diesel component yields, with only low formation of light gaseous components. At the same time, the quality of the SAF and the winter grade diesel components were superior compared to those obtained using the process of Reference 2, as evident based on the very low freezing point of the SAF and cloud point of the winter diesel components. As a significant benefit over the process of Reference 2, the improvements were achieved while avoiding the limitations of the process of Reference 2, i.e. without the need to use high severity HI, typically involving inter alia elevated temperature and/or lower WHSV compared to medium-severity HI conditions, and/or use of a fresh HI catalyst. Compared to the process of the HC process 1 , HC process 2 provided higher combined yield of the products considered most valuable in the present context, i.e. SAP and winter grade diesel components, with less light gaseous components being formed. Also, the quality of the SAP and the winter grade diesel components were better compared to those obtained using the HC process 1 , based on the freezing point of the SAP and cloud point of the winter diesel component. While in this experiment HC process 2 was run without a recycle stream, HC process 1 makes it evident that the SAP component yield could be easily significantly increased, when needed, by recycling at least a portion of the diesel component to the hydrocracking.

Table 5. Results from the simulation tests, yields based on raw material feed (oxygenated hydrocarbons)

Table 6. Product properties. SAP denotes sustainable/renewable aviation fuel component.

While these simulations of HC process 1 and HC process 2 were conducted without subjecting the hydrocracking effluent to hydroisomerisation before recovering the components from fractionation, based on the test run results shown in Example 1 it is evident that by replacing the hydrocracking catalyst with a catalyst system containing same total amount of catalyst but arranged as HC catalyst followed by HI catalyst, improved cold properties, reduced amount of generated light gases, and increased combined yield of the diesel and the aviation fuel component could be attained similarly as demonstrated in Example 1. Additionally, as is evident based on comparison of HC process 1 and HC process 2, by recovering a recycle stream in the present process and subjecting it as a cofeed i.e. as a part of the first reaction section feed to the hydrocracking, the aviation fuel component yield could be adjusted or optimised.

Example 3 - Simulations 2

Further simulations were carried out using Aspen Plus V10.0 software for showing the effect of varying weight ratio of the hydrocracking catalyst in the first reaction section to the hydroisomerisation catalyst in the second reaction section.

In these simulations two different feeds were used: a highly isoparaffinic Feed E (as in Table 1), and highly n-paraffinic Feed N containing about 100 wt-% paraffins, whereof about 5 wt- % were isoparaffins. Highly n-paraffinic feeds with low isoparaffin contents may be prepared e.g. by conducting HDO of an oxygenated hydrocarbon feed such as animal fat/vegetable oil using suitable process conditions, co-catalyst and/or product recycle(s), i.e. a separate isomerization step may not be required to achieve low isoparaffin levels.

Hence, in case of Feed E, the overall process set-up for the test points was HDO followed by initial HI, then hydrocracking, hydroisomerising and fractionating, and in case of Feed N, HDO followed by hydrocracking, then hydroisomerising and fractionating. In these simulations there was no recycling from the fractionation to the hydrocracking. As Reference was selected a conventional HVO process run in winter grade renewable diesel production mode, i.e. involving a HDO step followed by a medium severity HI step, but without any hydrocracking step.

In the simulations, the yield of the aviation fuel component (SAF) was maximized against minimum flash point (38°C), minimum freezing point (-40.0°C) and maximum density (772.0 kg/m ³ ). For Reference, the hydroisomerisation was conducted at 330°C, 40 bar, and WHSV 1.7h ^-1 , and for the other test points the hydrocracking was conducted at 280°C, hydroisomerisation at 320°C, and both steps at about 40 bar and WHSV 1.5h ^-1 . Yields of diesel fuel component, SAP, gasoline fuel component and light gases are reported in Table 7, and certain properties of the fuel components recovered from the fractionation are reported in Table 8.

Table 7. Yields calculated based on liquid product from HDO. SAF denotes sustainable/renewable aviation fuel component.

Table 8. Product properties. SAP denotes sustainable/renewable aviation fuel component.

From the results presented in Table 7, it can be seen that already with a weight ratio of 5:95 of the hydrocracking catalyst in the first reaction section to the hydroisomerisation catalyst in the second reaction section it was possible to achieve, in case of highly isoparaffinic Feed

E, a significant increase in SAF yield with only modest decrease in combined yield of diesel and SAF, or in case of highly n-paraffinic Feed N, reduction in the formation of light gases while maintaining the combined yield of diesel and SAF. By further increasing the share of the HC catalyst the benefits were further enhanced, i.e. in case of highly isoparaffinic Feed

E a further increase in SAF yield with only slight decrease in combined yield of diesel and

SAF was achieved, and in case of highly n-paraffinic Feed N a further reduction in the formation of light gases with increased combined yield of diesel and SAF was achieved.

From Table 7 it can further be seen that when the weight ratio of the hydrocracking catalyst in the first reaction section to the hydroisomerisation catalyst in the second reaction section was controlled to be less than 80:20, it was possible to suppress the formation of light gases even in case of the highly isoparaffinic Feed E. At the same time higher combined yields of diesel and SAF were obtained both with the highly isoparaffinic Feed E and the highly n- paraffinic Feed N. Also the density of the SAF component remained higher, as can be seen from Table 8, which is beneficial for blending with fossil components to provide the final aviation fuel, otherwise it may not be possible to reach the required minimum density of the final aviation fuel (775 kg/m ³ ) with the usual fossil blending components, but special fossil components may be required. Table 8 also shows that, when the HC:HI catalyst weightratio was limited to less than 80:20, both feeds provided diesel component with better cloud point (less than -15°C).

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.

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.