Process for producing bioalkylate or bio-sourced gasoline

Abstract

A process for producing an alkylate from a hydrocarbon source of renewable origin, said process comprising a step of alkylation of a first olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins with a second feedstock comprising at least isobutane, said second feedstock being obtained by partial or total hydrogenation of at least a fraction of said first olefinic feedstock to obtain a first effluent comprising a bioalkylate, said alkylation step being carried out in the presence of an acid catalyst in liquid or solid form, at a temperature of between -3°C and 90°C, at a pressure of between 0.01 and 2.0 MPa relative, and an isobutane / C3 to C4 olefins ratio of between 8 / 1 and 20 / 1 by volume.

Description

Title of the invention: Process for the production of bioalkylate or bio-sourced gasoline Technical field

[0001] The present invention applies in the field of the production of bio-sourced gasoline or bio-sourced alkylate (also called "bioalkylate" or alkylate obtained from a hydrocarbon source of renewable origin) the use of which is expected to increase to fuel gasoline vehicles (but also lawnmowers, chainsaws, jet skis, boats, etc.). This bio-sourced gasoline can advantageously be used pure, without mixing with other fossil bases emitting greenhouse gases, or toxic or carcinogenic gases such as, for example, aromatic or olefinic compounds. State of the art

[0002] In the context of reducing greenhouse gases, the production of bio-sourced gasoline makes it possible to reduce the consumption of fossil-based gasoline.

[0003] Ethanol is already widely used as a biofuel in gasoline engines, although developments are underway to provide a process for producing middle distillate hydrocarbon bases (diesel and / or kerosene) and preferably kerosene bases that can be incorporated into the fuel pool and at high yields, from ethanol produced from a renewable source derived from biomass, also called bioethanol (see patent FR 2959752).

[0004] Indeed, ethanol has notable advantages for its integration into gasoline, namely a high octane rating, miscibility in all proportions in gasolines and a similar density. It is an energy vector derived from agriculture and belonging to the family of renewable energies. There are several types of fuels containing ethanol, most of which are mixtures of gasoline and ethanol in different proportions. They are designated by the letter E followed by the percentage of ethanol in the mixture: for example, E85 represents a fuel containing 85% by weight of ethanol and 15% by weight of gasoline. In this nomenclature, E100 designates pure ethanol. We thus find E5, E7, E10, E15, E20, E85, E95, E100 depending on the country in which we are located and the use we want to make of it.

[0005] In France, the marketing of E85 to individuals, legally called Superéthanol, has been official since January 1, 2007 but requires modification of the vehicle's injection computer.

[0006] Currently, the existing fleet of vehicles cannot be powered 100% by alcohol or an oxygenated product, with rare exceptions of specifically designed models.

[0007] Oxygenates and alcohols are therefore essentially additives, mixed with other “classic” components of fossil origin.

[0008] A challenge in the production of bio-sourced gasoline is to remove this obstacle, by producing in a bio-sourced manner a product that can exceed 10% by weight of ethanol if we take as an example the limit of ethanol in Europe, or 2.7% by weight / 3.7% by weight for other oxygenates. The bioalkylate has all the qualities necessary to fuel a gasoline vehicle. It can constitute 100% by weight of the fuel of a vehicle without making any modifications. Only the density can turn out to be slightly lower than the specification: approximately 700 kg / m3 while the specification is 720-775 kg / m3 for Europe.

[0009] The production of alkylate gasoline can be achieved by an alkylation process involving the reaction of a light olefin such as propylene and butylene with an isoparaffin such as isobutane in the presence of an acid catalyst, such as H2SO4, and HF to form highly branched isoparaffins called alkylate.

[0010] Typical sources of light olefins in fossil fuel hydrocarbon conversion processes are catalytic cracking, coking, or visbreaking units. US Patent 4,211,885 discloses a process for producing high octane gasolines including alkylation of a butene stream with isobutane.

[0011] Light olefin cuts of biosourced origin can be obtained by different routes, in particular by dehydration of alcohols resulting from the transformation of lignocellulosic biomass (wood, grass, straw and other agricultural waste) or after transformation of effluents from the Fischer-Tropsch process. Light olefin cuts obtained by processes capturing and then recycling the CO2 present in industrial effluents or in the air (“Direct Captur”) are also considered renewable.

[0012] According to the prior art, the processes for producing an alkylate from light olefins react them with an isobutane stream produced from a hydrocarbon source separate from the light olefin stream.

[0013] For example, US patent 6,768,035 discloses a process for converting olefins contained in the light fraction of Fischer-Tropsch effluent into alkylate comprising the following steps:

[0014] - a stream of C3-C4 olefins from a Fischer-Tropsch process is simultaneously dehydrated and isomerized to convert 1-butenes to 2-butenes and alcohols to olefins;

[0015] - another fraction from the Fischer-Tropsch process is hydrotreated and hydrocracked to provide liquid distillates and an isobutane stream;

[0016] - the C3-C4 olefin stream is contacted with the isobutane stream to provide a highly branched isoparaffinic alkylate with a high octane number.

[0017] US Patent 4,654,453 describes a process in which aliphatic oxygenated compounds, in particular methanol, are converted by a process integrating three reaction zones. In a first reaction zone called "MTG", the oxygenated compounds are directly converted into gasoline called "MTG" and into an isobutane by-product. In a second reaction zone called "MTO", the oxygenated compounds are dehydrated into an intermediate product comprising in particular C3-C4 olefins. In a third alkylation reaction zone, the C3-C4 olefins react with the isobutane from the "MTG" to give a gasoline alkylate.

[0018] In these two prior art patents (US 6,768,035 and US 4,654,453), it is necessary to add an additional stream of isobutane to the olefin stream at the inlet of the alkylation process. In addition, these processes are complex because they require several reaction sections and several separation steps to obtain the desired products.

[0019] The Applicant has developed a process for producing bioalkylate that is partly or totally biosourced from a single olefinic feedstock. The process according to the invention comprises a step of alkylation of an olefinic feedstock that is partly or totally of renewable origin mixed with a second feedstock rich in isobutane produced at least partially or totally by a step of hydrogenation of a portion of said olefinic feedstock. Said olefinic feedstock advantageously comprises isobutene and C3 to C4 monoolefins, in particular butenes, and propylene. Said process has a “gasoline” yield equivalent to or greater than existing processes for producing biosourced gasoline from a single source of biosourced olefins.

[0020] The process according to the invention makes it possible in particular to produce a bio-sourced gasoline or a bioalkylate having the following advantages:

[0021] - its composition is essentially paraffinic with a high octane number (with a RON for Research Octane Number according to Anglo-Saxon terminology between 90 and 98);

[0022] - this gasoline is free of olefins and aromatics (including benzene) whose content is limited in gasoline;

[0023] - this gasoline is sulfur-free and has a low vapor pressure. The properties of this fuel are therefore excellent compared to other gasoline blends available on the market, particularly those of fossil origin;

[0024] - this essence is free from toxic or carcinogenic compounds, when it is used pure, not mixed;

[0025] - this gasoline can power a gasoline vehicle (but also a lawnmower, chainsaw, jet ski, boat...) without having to modify the engine.

[0026] The use of pure fuel makes it possible not to mix it with one or more fossil gasoline bases emitting greenhouse gases, or toxic gases or comprising carcinogenic compounds such as, for example, aromatic or olefinic compounds.

[0027] The bio-sourced gasoline produced by the process according to the invention can however be mixed with fossil gasoline bases in the ecological transition phase (for example reformate, isomerate, naphtha). It will advantageously allow the concentrations of olefins, aromatics, sulfur or octane number to be adjusted.

[0028] The process according to the invention can be implemented without co-production of kerosene and therefore be oriented towards 100% gasoline production.

[0029] The method according to the invention can optionally be installed independently, without necessarily being built in an existing industrial site, typically independently of a petroleum products / petrochemical refinery. Objects of the invention

[0030] The subject of the present invention is a process for producing an alkylate comprising at least:

[0031] a) a step of hydrogenation of at least one mass fraction "1-X" of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVH of between 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1;

[0032] b) an alkylation step of at least:

[0033] - either said at least partially hydrogenated stream comprising isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is strictly greater than 0 and strictly less than 1;

[0034] - either said at least partially hydrogenated stream comprising isobutane when X = 0;

[0035] in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 MPa relative and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate.

[0036] According to one or more embodiments according to the invention, said first effluent comprising an alkylate is sent to at least one separation step c) to obtain at least one second effluent comprising said alkylate and at least one third effluent comprising isobutane, characterized in that said third effluent comprising isobutane is recycled upstream of the alkylation step b).

[0037] According to one or more embodiments according to the invention, said separation step c) is characterized by the following sequence:

[0038] - said first effluent comprising an alkylate is sent into a first column to be distilled allowing the recovery of isobutane at the top of said first column and a stream comprising at least the alkylate and n-butane at the bottom of said first column;

[0039] - said stream comprising at least the alkylate and n-butane at the bottom of said first column is sent to a second distillation column making it possible to recover a flow comprising at least n-butane at the top of said second column and the second effluent comprising said alkylate at the bottom of said second column.

[0040] According to one or more embodiments according to the invention, said olefinic feedstock comprises at least 90% by weight of C4 olefins relative to the total weight of said feedstock.

[0041] According to one or more embodiments according to the invention, said olefinic feedstock comprises at least 90% by weight of isobutene relative to the total weight of said olefinic feedstock.

[0042] According to one or more embodiments according to the invention, the hydrogenation of the mass fraction “1-X” of said olefinic feedstock is total, it being understood that X is strictly greater than 0 and strictly less than 1.

[0043] According to one or more embodiments according to the invention, a first additional stream, preferably of renewable origin, comprising isobutane is sent to the alkylation step b) and / or to the separation step c).

[0044] According to one or more embodiments according to the invention, a separation step a') of the C1 and C2 hydrocarbon compounds is carried out between the hydrogenation step a) and the alkylation step b).

[0045] According to one or more embodiments according to the invention, said olefinic feedstock is 100% derived from renewable sources.

[0046] According to one or more embodiments according to the invention, said olefinic feedstock comes from alcohols of renewable origin, or from biomass, or from a Fischer-Tropsch unit or from a mixture of several renewable sources.

[0047] According to one or more embodiments according to the invention, said olefinic feedstock is obtained by dehydration of C3 and / or C4 alcohols of renewable origin.

[0048] According to one or more embodiments according to the invention, said olefinic feedstock is obtained by dehydration of n-butanol and / or isobutanol.

[0049] According to one or more embodiments according to the invention, said olefinic feedstock is obtained from C2 alcohol of renewable origin obtained according to the following steps:

[0050] - a step of dehydration of alcohol of renewable origin in C2 to produce a C2 olefinic charge;

[0051] - a step of dimerization of said C2 olefinic charge to obtain a charge C4 olefinic.

[0052] According to one or more embodiments according to the invention, the n-butane separated at the top of said second distillation column is sent to an isomerization step d) to isomerize the n-butane and obtain a mixture of isobutane and n-butane which is returned to the separation step c).

[0053] According to one or more embodiments according to the invention, a second additional stream comprising n-butane is sent to an isomerization step d) to obtain a stream comprising a mixture of isobutane and n-butane which is then introduced into the separation step c).

[0054] Another subject of the invention relates to a process for producing an alkylate comprising at least:

[0055] a) a step of hydrogenation of at least one mass fraction "1-X" of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVH of between 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising n-paraffins and / or isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1;

[0056] b) an alkylation step of at least:

[0057] - either said at least partially hydrogenated stream comprising n-paraffins and / or isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is strictly greater than 0 and strictly less than 1;

[0058] - either said at least partially hydrogenated stream comprising n-paraffins and / or isobutane when X = 0;

[0059] in admixture with at least a portion of the isobutane formed by isomerization in step d) then separated in step c), in the presence of an acid catalyst in liquid form or solid, at a temperature between -3°C and 90°C, at a pressure between 0.01 and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate,

[0060] c) a separation step comprising at least the following steps:

[0061] - said first effluent comprising an alkylate is sent into a first column to be distilled allowing the recovery of isobutane at the top of said first column and a stream comprising at least the alkylate and n-butane at the bottom of said first column; said isobutane recovered at the top of said first column is recycled upstream of the alkylation step b)

[0062] - said stream comprising at least the alkylate and n-butane at the bottom of said first column is sent to a second distillation column making it possible to recover a flow comprising at least n-butane at the top of said second column and the second effluent comprising said alkylate at the bottom of said second column,

[0063] d) a step of isomerization of the n-butane obtained at the top of said second column at the end of step c) and / or of an additional flow of n-butane to obtain a mixture of isobutane and n-butane which is returned upstream of the first column of step c).

[0064] Another subject of the invention relates to an alkylate capable of being obtained by the process according to the invention, characterized in that its modern carbon content measured according to standard ASTM D 6866-21 is greater than 50, preferably greater than or equal to 100. Description of the figures

[0065] [Fig.l] [Fig.l] represents a process diagram for producing a bioalkylate from an olefinic feedstock at least partly of renewable origin comprising C3 - C4 olefins according to a particular embodiment of the invention.

[0066] [Fig.2a] [Fig.2a] represents a detailed diagram of the process for preparing said olefinic feedstock from renewable C3-C4 alcohols according to a particular embodiment of the invention.

[0067] [Fig.2b] [Fig.2b] represents a detailed diagram of the process for preparing said olefinic feedstock from bioethanol according to a particular embodiment according to the invention.

[0068] [Fig.3] [Fig.3] represents a detailed diagram of the step of separation and recovery of the bioalkylate according to a particular embodiment of the invention. Detailed description Definitions

[0069] In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the method. However, it will be apparent to those skilled in the art that the method may be implemented without necessarily all of these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0070] It is specified that, throughout this description, the expression “between ... and ...” must be understood as including the limits cited, unless otherwise specified.

[0071] In this description, the term "comprise" is synonymous with (means the same as) "comprise", "include" and "contain", and is inclusive or open and does not exclude other elements that are not mentioned. It is understood that the term "comprise" includes the exclusive and closed term "consist".

[0072] Furthermore, when used in the present description, the terms "essentially" or "substantially" or "approximately" in relation to a reference value correspond to an approximation of ± 10%, preferably ± 5%, very preferably ± 2%, or even more preferably ± 1% of this reference value, which may be a temperature, a pressure, a distance, a speed, a flow rate, a content of compound(s), etc.

[0073] Within the meaning of the present invention, the various embodiments presented may be implemented separately or in combination with each other, without limitation of combinations when this is technically feasible.

[0074] In the sense of the present invention, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​may be combined with a more preferred range of temperature values.

[0075] The term "bio-sourced" or "renewable" means that the material / product / compound it qualifies is an organic material / product / compound whose carbon comes from the CO2 present in the atmosphere fixed recently (on a human scale), in particular thanks to solar energy (photosynthesis). On land, this CO2 is captured or fixed by plant life (for example, agricultural crops or forestry materials). In the oceans, CO2 is captured or fixed by photosynthesizing bacteria or phytoplankton. For example, a bio-sourced material has a 14C / 12C isotopic ratio greater than 0. Conversely, a material of fossil origin has a 14C / 12C isotopic ratio of approximately 0. The terms "renewable" or "derived from renewable" can also be used. To determine whether a material / product / compound is bio-sourced or derived from renewable, its modern carbon content (or percent modern carbon, pMC, according to the Anglo-Saxon term) is measured according to ASTM D 6866-21 (“Determination of Bio-Based Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis”). The method of this standard measures the 14C / 12C isotope ratio in a sample and compares it to the 14C / 12C isotope ratio of a standard bio-based reference to obtain the percentage of bio-based content of the sample, the reference giving a radiocarbon content approximately equivalent to the atmospheric radiocarbon fraction in 1950. The pMC of the standard bio-based reference material is therefore equal to 100%. The pMC of a fossil-based material is approximately 0%. A current bio-based material may therefore also have a pMC greater than 100%.In the text, the prefix “Bio” can also be used in front of the type of compound to characterize its biosourced nature: for example, bioalkylate, biomethanol, bioethanol, bio-butanols, bio-isobutanol.

[0076] By extension, certain olefinic feedstocks of renewable origin according to the invention can be obtained from captured carbon dioxide, either in a flow emitted by an industrial process or in the air. In this case, the production of olefinic feedstock makes it possible to capture a flow of CO2 linked to human activities. The olefinic feedstock from the captured CO2 can for example be produced by the Fischer-Tropsch route. The alkylate produced is then a fuel based on recycled carbon ("Recycled Carbon Fuel" according to English terminology). This type of fuel belongs to renewable fuels according to the European Union classification. However, the pMC of the olefinic feedstocks obtained from CO2 will be lower or even zero if it comes from industrial effluent.

[0077] The English terms "Research Octane Number (RON)" and "Motor Octane Number (MON)" for the research or motor octane number respectively are measures of the performance of gasoline engines. RON is defined by ASTM methods D2699 and D2885, and MON is defined by ASTM methods D2700 and D2885.

[0078] The term "conventional feedstock" or "conventional product" means any feedstock or product respectively all of whose carbon originally comes from fossil sources, such as oil, gas and coal.

[0079] The term "gasoline" refers to a mixture generally comprising primarily hydrocarbon compounds that can be used to operate spark-ignition engines (e.g., automobile engines) and is more volatile than kerosene or diesel. Gasoline may also include additives such as alcohols and other oxygenated organic compounds. Concretely, the mixture of hydrocarbons and optional additives called gasoline must at least meet the ASTM D4814 standard.

[0080] According to the present invention, the term "olefin" refers to hydrocarbons comprising one double bond. The term "mono-olefin" refers to hydrocarbons comprising one double bond while the term di-olefin refers to hydrocarbons comprising two double bonds.

[0081] In the present description, the term “Cx hydrocarbons” (e.g. C4 olefins) designates hydrocarbon compounds comprising x carbon atoms. The term “Cx+ hydrocarbons” designates hydrocarbon compounds having at least x carbon atoms. The term “Cx to Cy hydrocarbons” designates hydrocarbon compounds having between x and y carbon atoms.

[0082] In the present description, the groups of chemical elements are given by default according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIIIB according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUP AC classification; group VIB according to the CAS classification corresponds to the metals of column 6 according to the new IUPAC classification.

[0083] By hourly volumetric flow rate “WH”, we mean the volumetric flow rate of the feed at the reactor inlet in m3 / h at 15°C, 0.1 MPa divided by the volume of catalyst in m3 contained in the reactor.

[0084] By hourly volumetric velocity “PPH”, we mean the mass flow rate of the feed at the reactor inlet in kg / h at 15°C, 0.1 MPa divided by the mass of catalyst in kg contained in the reactor.

[0085] In this description, pressures are expressed as relative values, unless otherwise specified.

[0086] According to the invention, the mass fraction “X” denotes the fraction of the mass flow rate of the olefinic feedstock which bypasses the hydrogenation step, and which will not be hydrogenated.

[0087] According to the invention, the mass fraction “1-X” denotes the fraction of the mass flow rate of the olefinic feedstock which is hydrogenated; with X being a number strictly greater than or equal to 0 and strictly less than 1.

[0088] According to the invention, the mass fraction “X” is equal to the ratio between the difference (total mass flow rate of the olefinic feedstock less mass flow rate of the olefinic feedstock sent to hydrogenation) divided by the total mass flow rate of the olefinic feedstock.

[0089] According to the invention, the mass fraction “1-X” is equal to the mass flow rate of the olefinic feed sent to the hydrogenation divided by the total mass flow rate of the olefinic feed.

[0090] According to the invention, the total mass flow rate of the olefinic feedstock is equal to the sum of the mass flow rate of the feedstock not sent to hydrogenation and the mass flow rate of the feedstock sent to hydrogenation.

[0091] For example, referring to [Fig.l] schematically illustrating an embodiment of the method according to the invention, we have:

[0092] X = mass flow rate of feed not sent to hydrogenation (103) / total mass flow rate of olefinic feed (101) = (total mass flow rate of olefinic feed (101) - mass flow rate of olefinic feed sent to hydrogenation (102)) / total mass flow rate of olefinic feed (101);

[0093] 1-X = mass flow rate of olefinic feed sent to hydrogenation (102) / flow rate total mass of the olefinic feedstock (101); and

[0094] Total mass flow rate of olefinic feed (101) = mass flow rate of feed not sent to hydrogenation (103) + mass flow rate of olefinic feed sent to hydrogenation (102).

[0095] According to the invention, the hydrogenation rate is defined as the ratio of the quantity of olefins having been converted into paraffins during the hydrogenation step to the quantity of olefins initially present in the charge of the hydrogenation unit according to the following equation:

[0096] [Math.l] Hydration rate (%) = 1ÜD X ::--------—:---------- ene / nœs between# — ; Detailed description

[0097] The subject of the present invention is a process for producing an alkylate comprising at least:

[0098] a) a step of hydrogenation of at least one mass fraction "1-X" of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVH of between 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1;

[0099] b) an alkylation step of at least:

[0100] - either said at least partially hydrogenated stream comprising isobutane, obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at less partly of renewable origin comprising C3 to C4 olefins, it being understood that X is strictly greater than 0 and strictly less than 1;

[0101] - either said at least partially hydrogenated stream comprising isobutane when X = 0;

[0102] in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate. The charges

[0103] The olefinic feedstock comprises C3 to C4 olefins at least partly of renewable origin. Preferably the C3 to C4 olefins are isobutene and C3 to C4 monoolefins, i.e. it comprises isobutene as well as, for example, butenes and / or propylene.

[0104] An olefinic feedstock particularly suitable for the process according to the invention is an olefinic feedstock essentially C3 (propylene) and / or C4 (n-butene, isobutene), i.e. at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight of C3 and / or C4 olefins relative to the total weight of olefins contained in the olefinic feedstock.

[0105] Advantageously, the olefinic feedstock comprises at least 90% of C4 olefins (n-butene, isobutene). The olefinic feedstock may in particular be chosen from a feedstock consisting essentially of isobutene (i.e. at least 90% by weight of isobutene) or a feedstock consisting essentially of n-butenes (but-1-ene and but-2-ene) (i.e. at least 90% by weight of but-1-ene and but-2-ene), or mixtures thereof.

[0106] In one embodiment according to the invention, the olefinic feedstock may be a C4 olefinic cut which comprises at least 98% by weight of n-butenes, 1-butene and 2-butene, preferably less than 2% of n-butane, and preferably less than 0.5% of n-butane, the percentages being given relative to the total weight of the olefinic feedstock. In this embodiment, an isobutane feedstock, preferably renewable, is necessary to start the process and constitute the excess isobutane in the reactor. In addition, the process according to the invention may comprise an isomerization unit making it possible to transform a portion of the butanes resulting from the hydrogenation step into isobutane. The isobutane is then sent to the alkylation step. Once the isomerization has started, the additional renewable isobutane feedstock is no longer necessary. This embodiment is detailed later.

[0107] In another embodiment according to the invention, the olefinic feedstock may be a C4 olefinic cut which comprises at least 90% by weight of isobutene, or even at least 92% by weight of isobutene, and in particular at least 97% by weight of isobutene, and optionally butane and / or isobutane and / or n-butenes, in particular between 3 and 10% by weight of butane and / or isobutane and / or n-butenes, the percentages being given in relation to the total weight of the olefinic charge.

[0108] Preferably, the olefinic feedstock is free of sulfur or sulfur compounds, i.e. it comprises a content of less than or equal to 1 ppm by weight of sulfur element relative to the weight of the olefinic feedstock, thus making it possible to limit the consumption of acid in the alkylation if the catalyst is acidic. If the olefinic feedstock contains sulfur, the process advantageously comprises a step of pretreatment of the olefinic feedstock preferably implementing an adsorption section and / or a water washing section and / or a dedicated hydrotreatment section to remove the sulfur.

[0109] The olefinic feedstock is at least partly obtained from a hydrocarbon source of renewable origin, including hydrocarbon sources produced from carbon dioxide recycling.

[0110] Advantageously, the olefinic feedstock is entirely biosourced, that is to say entirely obtained from a hydrocarbon source of renewable origin, in order to produce fully biosourced products that can be recovered.

[0111] Said olefinic feedstock may typically be derived either from a Fischer Tropsch unit or from a unit for producing olefins from methanol and / or from a unit for dehydrating alcohols, for example ethanol or butanol / isobutanol, in particular alcohols derived from biomass, for example from the fermentation of sugars. It may also be produced directly from biomass by bacteria. It may also be a mixture of different sources of renewable origin.

[0112] When the olefinic feedstock comes from an alcohol dehydration or dehydration / isomerization unit, the alcohols are preferably derived at least in part from the transformation of biomass such as, for example, cellulosic raw materials, i.e. consisting of more than 90% by weight of cellulose, and / or lignocellulosic raw materials, i.e. consisting of cellulose, hemicelluloses, which are polysaccharides essentially consisting of pentoses and hexoses, as well as lignin, which is a macromolecule of complex structure and high molecular weight, composed of aromatic alcohols linked by ether bonds.

[0113] Preferably, the olefinic feedstock can be obtained by dehydration or dehydration / isomerization of renewable 4-carbon alcohols, in particular isobutanol and / or butanols.

[0114] Advantageously, the olefinic feedstock is obtained by dehydration of isobutanol from the fermentation of carbohydrates (sugars) present in the biomass as disclosed in patent application WO2009 / 079213.

[0115] Butanols or isobutanol may be produced, for example, by microorganisms as described in patent application publications US2007 / 0092957, US2008 / 0138870, US2008 / 0182308, US2007 / 0259410, US2007 / 0292927, US2007 / 0259411, US2008 / 0124774, US2008 / 0261230, US2009 / 0226991, US2009 / 0226990, US2009 / 0171129, US2009 / 0215137, US2009 / 0155869, US2009 / 0155869 and US2008 / 02745425.

[0116] Preferably, the biosourced isobutanol is then dehydrated into isobutene according to the process described in patent EP 3162763 or patent US8975461.

[0117] In another variant, the olefinic feedstock can be obtained by dehydration or dehydration / isomerization of renewable 2-carbon alcohols, followed by an oligomerization step, preferably in homogeneous phase, and a separation step to form an olefinic cut rich in 4-carbon compounds as described in patent FR2959752.

[0118] In another variant, the olefinic feedstock of isobutene can be directly obtained from bioresources, in particular as described in patent EP2630236, for example from polysaccharides (sugars, starches, celluloses, etc.). In this case, the isobutene content is preferably greater than 90% by weight relative to the total weight of the olefinic feedstock.

[0119] The olefinic feedstock may also come at least in part from a conventional (i.e. fossil) source. In this case, it is preferably implemented with a conventional olefinic feedstock: biosourced olefinic feedstock ratio of between 90:10 and 10:90 by weight, preferably between 80:20 and 20:80, preferably between 60:40 and 40:60. A conventional olefinic feedstock may typically come from a steam cracking unit, an FCC (Fluid Catalytic Cracking) unit, a selective diolefin hydrogenation unit (known as a SHU unit), or a paraffin dehydrogenation unit, pure or as a mixture and / or any other unit leading to the production of light C3 to C4 olefins.

[0120] The olefinic feedstock corresponds in particular to the streams (101) in figures 1, 2a and 2b illustrating the invention.

[0121] The steps of the method according to the invention are described in detail below. a) Hydrogenation step

[0122] Said olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins is separated into two fractions “X” and “1-X” which will undergo different treatments:

[0123] - a mass fraction “1- X” (corresponding to the flow (102) in [Fig.l]);

[0124] - a mass fraction “X” (corresponding to the flow (103) in [Fig.l]);

[0125] it being understood that X is greater than or equal to 0 and strictly less than 1.

[0126] The mass fraction “X” does not undergo any treatment and avoids (bypass according to English terminology) the hydrogenation step. The composition of the mass fraction “X” is strictly identical to that of the olefinic feedstock. Only the mass flow rate between the olefinic feedstock and the fraction which does not undergo any treatment differs, the flow rate of the mass fraction “X” being lower than that of the olefinic feedstock. The mass fraction X is possibly non-existent if the entire olefinic feedstock is sent to the hydrogenation step a) (“X” is then equal to 0). The mass fraction “1-X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins is sent to a hydrogenation step a) to obtain an at least partially hydrogenated stream (corresponding to stream (104) of [Fig.l]) comprising isobutane.

[0127] The non-hydrogenated fraction “X” and the at least partially hydrogenated fraction “1-X” are then recombined to form a mixture comprising at least C3 to C4 olefins and isobutane (corresponding to stream (105) of [Fig.l]) which can be sent to the alkylation step b). The mixture can also be sent beforehand to a step a') of separation of the C1 and C2 hydrocarbon compounds which is described below.

[0128] When X is equal to zero, the fraction "X" of the non-hydrogenated feedstock is zero. The entire olefinic feedstock is then sent to hydrogenation step a) and is partially hydrogenated to obtain a mixture comprising C3 to C4 olefins and isobutane (corresponding to stream (105) of [Fig.l]).

[0129] The choice between the two variants is made by the person skilled in the art depending on the composition of the feedstock or depending on other parameters, such as, for example, the technical feasibility of being able to reuse existing units. If the olefin feedstock contains propylene, it may be considered to keep part of it or not, depending on the desired quality of alkylate.

[0130] The hydrogenation step a) makes it possible to hydrogenate the olefins contained in the “1-X” fraction of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins without selectively preserving the mono-olefins, unlike selective hydrogenation, a reaction in which only the di-olefins are hydrogenated so as to produce a cut no longer containing di-olefins, but having retained its mono-olefins. This hydrogenation can be total or partial.

[0131] The composition of the at least partially hydrogenated stream depends on the composition of the olefinic feedstock; paraffins corresponding to the olefins are produced. In particular, if the first olefinic feedstock contains isobutene, then the product resulting from the hydrogenation according to step a) comprises isobutane. The composition of the remainder of the cut produced depends on the composition of the first feedstock olefinic. This comprising isobutene and C3 to C4 monoolefins, in particular butenes, propylene, the corresponding paraffins are produced: C3 to C4 paraffins, in particular butanes and propane. In particular, when the first charge comprises isobutene and / or butenes, the cut produced comprises isobutane and / or butanes.

[0132] Preferably, said at least partially hydrogenated stream comprises isobutane, preferably at least 50% by weight of isobutane, preferably at least 70% by weight, preferably at least 90% by weight of isobutane relative to the total weight of said at least partially hydrogenated stream.

[0133] The hydrogenation step is typically carried out in the liquid phase, at a temperature between 50°C and 150°C, a WH between 0.5 h 1 and 4.0 h1, preferably between 1 h 1 and 3 h1, at a pressure between 1.8 MPa and 6.0 MPa, preferably between 2.0 MPa and 4.0 MPa, in the presence of hydrogen, preferably renewable. The hydrogen flow rate is adjusted in order to regulate the hydrogenation rate.

[0134] Preferably, the hydrogenation step is carried out in the presence of a catalyst preferably comprising at least one metal from group VIII, in particular nickel or palladium or platinum, deposited on an inert support, such as silica or alumina. Preferably, the hydrogenation step is carried out in the presence of a palladium or nickel-based catalyst on an alumina support. However, any other catalyst making it possible to hydrogenate the compounds of the first charge can be used.

[0135] When the group VIII metal is palladium, the palladium content is preferably between 0.01% and 2% by weight of palladium element relative to the total weight of the catalyst, preferably 0.03% and 0.8% by weight.

[0136] When the group VIII metal is nickel, the nickel content is preferably between 1% and 50% by weight of nickel element relative to the total weight of catalyst, preferably between 5% and 40% by weight and more preferably between 7% and 30% by weight.

[0137] To obtain good operation and yield of the process according to the invention, the alkylation step must be carried out at an isobutane / olefins ratio of between 8 / 1 and 20 / 1 by volume in the alkylation reactor. A person skilled in the art will thus be able to vary both the quantity of the olefinic feedstock to be sent to the hydrogenation step a), namely the mass fraction “1-X” and the hydrogenation rate of the “1-X” fraction of step a) to achieve this target ratio. This gives rise to different embodiments.

[0138] In a first variant, the mass fraction “1-X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins is completely hydrogenated to obtain a completely hydrogenated stream comprising isobutane. In this variant, the total hydrogenation produces a cut devoid of olefins. The non-hydrogenated mass fraction “X” and the fully hydrogenated mass fraction “1-X” are then recombined to form a mixture comprising at least olefins and paraffins, preferably comprising isobutane, which is sent to alkylation step b). In this variant, X is strictly greater than 0 and strictly less than 1. The non-hydrogenated mass fraction “X”, called the bypass fraction, will therefore be adjusted so as to respect the isobutane / olefins ratio in the alkylation reactor such that it is between 8 / 1 and 20 / 1 by volume. The hydrogenation rate of the mass fraction “1-X” is 100%.

[0139] In a second variant, the mass fraction "1-X" of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins is partially hydrogenated to obtain a partially hydrogenated stream comprising paraffins, isobutane. The non-hydrogenated mass fraction "X" and the partially hydrogenated mass fraction "1-X" are then recombined to form a mixture of olefins and isobutane which will be sent to the alkylation step b). In this second variant, X is strictly greater than 0 and strictly less than 1. The hydrogenation rate of the fraction "1-X" and the mass fraction "X" will consequently be adjusted so as to respect the isobutane / olefins ratio in the alkylation reactor such that it is between 8 / 1 and 20 / 1 by volume.

[0140] The non-hydrogenated mass fraction “X” (when X is strictly greater than zero) and the partially hydrogenated mass fraction “1-X” are then recombined to form a mixture comprising at least olefins and isobutane, which can be sent directly to the alkylation step b), or to an optional step of separation of the C1 and C2 hydrocarbon compounds (step a') before being sent to the alkylation step b).

[0141] In a third variant, the mass fraction "X" is zero. All of the olefinic feedstock, at least partly of renewable origin, is sent to the hydrogenation step a) to obtain a partially hydrogenated stream comprising C3 to C4 olefins and isobutane. The hydrogenation rate of the mass fraction "1-X" is adjusted so as to respect the isobutane / olefins ratio in the alkylation reactor such that it is between 8 / 1 and 20 / 1 by volume. A hydrogenation rate of at least 40%, preferably greater than or equal to 50%, is achieved.

[0142] a') Step of separation of hydrocarbon compounds into Cl and C2 (optional)

[0143] An optional stabilization step a') on the recombined stream comprising at least C3 to C4 olefins and isobutane makes it possible to eliminate the light compounds, essentially consisting of C1 to C2 hydrocarbon compounds, and form a mixture comprising at least C3 to C4 olefins and stabilized isobutane before the alkylation step b).

[0144] Typically, this step is carried out in one or more distillation columns, at a pressure typically between 1.3 MPa and 2.0 MPa relative.

[0145] This step is implemented in [Fig.l] by the separation unit (a') which separates the recombined stream (105) to form a stabilized olefin and isobutane mixture (111). Of course, if step a') is not carried out then the streams (105) and (111) as represented in [Fig.l] are identical. b) Alkylation step

[0146] According to the invention, the process comprises a step of alkylation of at least:

[0147] - either said at least partially hydrogenated stream comprising isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is strictly greater than 0 and strictly less than 1;

[0148] - either said at least partially hydrogenated stream comprising isobutane when X = 0;

[0149] in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 MPa relative and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate.

[0150] Alkylation is a reaction in which an alkyl group is added to an olefin. Thus, an isoparaffin can be reacted with an olefin to provide a higher molecular weight isoparaffin. Industrially, according to the invention, a C3 to C4 olefin reacts with isobutane in the presence of an acid catalyst to produce an alkylate. Linear paraffins (normal paraffins in English terminology), denoted "n-paraffins", are inert to alkylation.

[0151] When the nature of the catalyst and the reaction conditions are judiciously chosen (in particular the temperature), the process according to the invention allows the production of an alkylate having interesting properties with respect to the parameters sought for the specifications of fuels for engines and gasoline constituents, in particular as defined by the Euro-V standard. In order to limit side reactions, but also to shift the thermodynamic equilibria, a large excess of isobutane in the reactor is typically used. In addition, the alkylation reaction is characterized by a high exothermicity (approximately 83.6 kJ / mol of butene transformed if the olefin is butene and if the isoparaffin is isobutane). The large excess of isobutane then makes it possible to stabilize the temperature in the reactor.

[0152] The high excess of isobutane implies that the effluent from the alkylation reaction is rich in isobutane. After a separation step c) (described below), the isobutane is preferably recycled to the inlet of the alkylation reactor. This stream is for example represented by stream (212) in [Fig.l].

[0153] The mixture comprising at least olefins and stabilized isobutane (corresponding for example to the stream (111) of [Fig.l] when the mixture comprising olefins and isobutane (105) is sent beforehand to a step a') of separation of the hydrocarbon compounds C1 and C2) is sent to the alkylation step b) to produce a first effluent comprising a bioalkylate (corresponding for example to the stream (201) of [Fig.l]). It is understood that the mixture comprising at least olefins and isobutane (corresponding for example to the stream (105) in [Fig.l]) can be sent directly to the alkylation step b) without the latter being sent to the optional stabilization step a').

[0154] According to a variant of the process, when the olefinic feed sent to hydrogenation has a composition low in isobutene, therefore producing little isobutane during the hydrogenation step, an additional external stream rich in isobutane, preferably renewable, can be sent directly to the alkylation step. This additional stream is represented by the optional stream (112) in [Fig.l].

[0155] At the inlet of the alkylation stage, the isobutane / olefins volume ratio, in particular the isobutane / butenes volume ratio, and in particular the isobutane / isobutene volume ratio, in the alkylation reactor is between 8 / 1 and 20 / 1 by volume, preferably between 8 / 1 and 12 / 1 by volume. The adjustment of this isobutane / olefins ratio at the inlet of the alkylation stage depends on the nature of the olefinic feedstock. For a given load, the person skilled in the art has various levers for adjusting the isobutane / olefins ratio, such as: the mass fraction “X” of the bypass of the hydrogenation stage or the hydrogenation rate of the mass fraction “1-X”, the flow rate of the possible additional stream rich in preferably renewable isobutane as well as the flow rate of the possible isobutane stream coming from the optional isomerization unit.The excess isobutane present in the alkylation reactor is separated in separation step c) and preferably recycled to the reactor inlet.

[0156] The alkylation step is carried out in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 MPa relative and 2.0 MPa relative.

[0157] According to one embodiment, the alkylation process according to the invention is carried out with a liquid catalyst (typically sulfuric acid or an ionic liquid for existing commercial processes). Industrial alkylation processes have historically used catalysts based on hydrofluoric or sulfuric acid under relatively low temperature conditions. The sulfuric acid alkylation reaction is particularly sensitive to temperature, with low temperatures being preferred to minimize the secondary reaction of olefin polymerization. The acid concentration in these liquid acid-catalyzed alkylation processes is kept constant by the continuous addition of fresh acid and the continuous removal of spent acid.

[0158] For the case of the liquid catalyst, the reaction medium is two-phase. The continuous phase can be either the acid phase or the hydrocarbon phase. In general, the continuous phase is the acid phase; the acid catalyst constitutes a liquid phase which is brought into contact with the liquid isobutane-isobutene mixture to form an emulsion and the acid / hydrocarbon volume ratio is greater than 1. For example, in the case of the implementation of sulfuric acid by Stratco technology (LF Albright, Chem. Eng., August 15, 1966, p. 143 and LF Albright, Oil & Gas Journal, November 12, 1990), which is the most widespread, the emulsion is created, at one end of a horizontal reactor, by a turbine powered by the feedstock and the acid recycle. But an implementation where the continuous phase is the hydrocarbon phase is also conceivable (see for example PCT patent application W095 / 04019).

[0159] In the case where the catalyst is solid, the solid catalyst may be based on zeolite, the hourly space velocity, expressed in weight of olefin introduced per unit of weight of the catalyst and per hour (PPH) is typically between 0.001 h 1 and 10 h 1 and preferably between 0.002 h 1 and 2 h *.

[0160] The implementation of the catalyst used aims to obtain good homogeneity of temperature and reagent concentration. In particular, the implementation device comprises at least one reactor and at least one decanter (liquid catalysis) or a reactor and a separator drum (solid catalysis). A person skilled in the art will be able to use the teaching of patent US 5345027 for the implementation of the catalyst in its liquid form, which discloses a continuous alkylation process for the production of high octane gasoline comprising contacting a mixture of an isoparaffin and an olefin with a catalyst complex based on BF3:H3PO4 in a continuous downward flow reactor. c) Separation step (optional)

[0161] Said first effluent comprising an alkylate from the alkylation step b) (represented by the stream (201) of [Fig.l]) can be sent to at least one separation step c) to obtain at least one second effluent comprising said alkylate (represented by the stream (211) of [Fig.l]) and at least one third effluent comprising isobutane (represented by the stream (212) of [Fig.l]). Said third effluent comprising isobutane can be recycled upstream of the alkylation step b).

[0162] Preferably, a stream comprising linear paraffins, such as for example n-butane, is also separated from the effluent comprising an alkylate from the alkylation step b) (represented by the stream (302) in Figures 1 and 3). This stream is not negligible if the olefinic feedstock comprises butenes which are transformed into butane during the hydrogenation step. This stream can be recovered outside the process according to the invention. This stream can also be sent to an optional isomerization step d) (represented by the stream (302) in [Fig.l]).

[0163] Preferably, in the process according to the invention, the separation steps are shared between the different units. Preferably, the step of separating the effluent from the optional isomerization step d) is implemented in the same columns as the step of separating the effluent from the alkylation step b). For example, in the process implemented according to [Fig.l], the effluent from the isomerization (303) is sent to the separation section c). In addition, the separation step c) preferably produces a stream (302) rich in linear paraffins, in particular n-butane, which can be sent to the isomerization step.

[0164] Depending on the composition of the olefinic feedstock, the separation step is carried out in suitable columns, as known to those skilled in the art.

[0165] Preferably, the separation step comprises at least one first distillation column, called a deisobutanizer (or DIB). Said column advantageously treats part or all of the effluent from the alkylation step to separate isobutane, in particular excess isobutane, at the top of the column and a stream comprising at least the alkylate at the bottom of said deisobutanizer. The fraction separated at the bottom may also comprise n-butane and other inert compounds in the alkylation in the feed. This column may optionally be preceded by one or more separation columns to separate the lighter compounds such as propane for example.

[0166] Propane does not react in alkylation. It can typically be removed from the alkylation reaction section via the purge of a drum, in particular a drum from the unit's refrigeration loop, or if it is in larger quantities, a dedicated column can be installed. The depropanizer column in this case makes it possible to fractionate a propane cut which can then be recovered.

[0167] Preferably, the separation step also comprises at least one second distillation column, called a debutanizer, making it possible to recover a stream comprising at least n-butane and optionally other compounds at the top of said debutanizer and the second effluent comprising said alkylate. The stream separated at the bottom of this column constitutes the product of the unit and can be recovered. The separated n-butane stream can be sent to the optional isomerization step or recovered. This column can optionally be followed by one or more separation columns to separate compounds of interest from the alkylate.

[0168] Advantageously, the separation step c) can separate the effluent from the optional isomerization step d). The effluent from the optional isomerization step can be introduced in particular into the first deisobutanizer distillation column (or DIB) to separate the isobutane contained in this stream. The bottom of this column can then be fractionated directly or after other separation steps in the second debutanizer distillation column to separate the n-butane fraction, which is advantageously returned to the isomerization step d).

[0169] Advantageously, the separation step c) can separate an additional stream comprising isobutane or paraffins, preferably of renewable origin. This stream (represented for example by stream (112) of [Fig.3]) can be introduced upstream of the first column or the second column depending on its composition.

[0170] According to one embodiment of the invention, in particular when the olefinic feedstock is rich in butene and isobutene, the separation step c) is characterized by the following sequence, as described for example in [Fig.3]:

[0171] - said first effluent comprising an alkylate (represented by the flow (201) in the [Fig.3]) is sent to a first distillation column (Cl), called deisobutanizer (or DIB), making it possible to recover the isobutane at the top of the column (represented by the flow (212) of [Fig.3]) and a flow comprising at least the alkylate and n-butane at the bottom of said deisobutanizer (represented by the flow (211a) in [Fig.3]);

[0172] - said stream comprising at least the alkylate and n-butane, at the bottom of said deisobutanizer (21 la) is then sent to a second distillation column (C2), called debutanizer, making it possible to recover a stream comprising at least n-butane at the top of said debutanizer (represented by stream (302) in [Fig.3]) and the second effluent comprising said alkylate (represented by stream (211) in [Fig.3]).

[0173] The effluent from the optional isomerization step (represented by stream (303) in [Fig. 3]) can also be introduced upstream of column C1 to recover the isobutane formed during the isomerization step and recycle it upstream of the alkylation step. An additional stream comprising isobutane (represented for example by stream (112) in [Fig. 3]) can also be introduced upstream of column (C1) to recover the isobutane and recycle it upstream of the alkylation step.

[0174] Preferably, the deisobutanizer comprises a number of theoretical plates between 50 and 90 actual plates depending on the purity of the flow to be separated. The column is operated at a relative pressure typically greater than or equal to 0.4 MPa, preferably between 0.4 MPa and 0.8 MPa at the top of the column.

[0175] Preferably, the debutanizer comprises a number of theoretical plates greater than 15 theoretical plates, preferably between 20 and 40 theoretical plates. The column is typically operated at a relative pressure of between 0.4 MPa and 0.6 MPa at the column head. d) Isomerization step (optional)

[0176] In a variant of the process according to the invention, an isomerization step d) treats the stream comprising linear paraffins, such as for example n-butane, obtained in the separation step c). This stream is preferably sent to an isomerization step d).

[0177] In the isomerization step, a stream of n-paraffins, in particular a stream of n-butane, is isomerized in the presence of a catalyst to produce a mixture of isoparaffin and n-paraffin at thermodynamic equilibrium. If the isomerization feed is n-butane, a stream of isobutane and n-butane is produced, preferably at thermodynamic equilibrium, i.e. with a 60 / 40 mole ratio.

[0178] This isomerization step makes it possible to produce an effluent enriched in isobutane which can be returned to the alkylation step. Preferably, the effluent from isomerization step d) is first sent to separation step c).

[0179] In particular, if the initial olefinic feedstock comprises n-butene, the latter is partially or totally transformed into n-butane during the hydrogenation step a) which is inert in the alkylation step b).

[0180] The effluent from the isomerization step is enriched in isoparaffins which are capable of reacting in the alkylation step. The presence of the isomerization step therefore makes it possible to increase the yield of bioalkylate when the olefinic feedstock contains olefins which then give linear paraffins in the hydrogenation.

[0181] The effluent from the isomerization stage enriched in isoparaffins, in particular in isobutane, is fractionated to produce on the one hand a stream of isoparaffins, in particular isobutane and on the other hand a stream rich in linear paraffins which is advantageously recycled to the isomerization stage.

[0182] The fractionation is preferably carried out in separation step c), in particular upstream of the deisobutanizer CL

[0183] The isoparaffins, especially isobutane, produced in the isomerization are preferably sent to the alkylation (e.g., via stream (212), of [Fig.l]).

[0184] This isomerization step allows, optionally, in a variant of the process according to the invention to integrate one or more external paraffinic feeds, represented for example in [Fig. 1] by the optional flow (301). These feeds are, preferably, feeds of renewable origin. Said feeds are preferably rich in C4 paraffins, in particular in n-butane. For example, a cut of linear C4 paraffins, preferably at least partly renewable, can be sent to the isomerization step to produce an iso-paraffin / n-paraffin equilibrium mixture. Preferably, the isobutane thus produced is sent as a reactant to the alkylation and the linear paraffins (n-butane in particular) are recycled to the inlet of the isomerization.

[0185] The person skilled in the art will accordingly adjust the bypass fraction “X” of the hydrogenation step, the hydrogenation rate in step a), but also the flow rate of one or more external paraffinic or isoparaffinic feeds (represented by the flows (301) and (112) in [Fig.l], for example) in order to achieve an isobutane / olefins ratio in the alkylation reactor a) of between 8 / 1 and 20 / 1 by volume.

[0186] The conditions of the isomerization step are chosen so as to promote the transformation of n-paraffins (n-butane) into isoparaffins (isobutane).

[0187] The isomerization process is generally carried out in the presence of a catalyst chosen from three different known types of catalysts: Friedel and Crafts type catalysts, bifunctional zeolite catalysts comprising a group VIII metal deposited on a zeolite, and bifunctional metal / support catalysts based on group VIII metals, typically platinum deposited on alumina or based on sulfated zirconia, and generally containing a halogen, for example chlorine. The isomerization process according to the invention is preferably carried out in the presence of a catalyst based on chlorinated alumina and platinum.Typically, the isomerization process is carried out at low temperature, for example between 100°C and 300°C, preferably between 110°C and 240°C, and at high pressure, for example a pressure between 2.0 MPa relative and 3.5 MPa relative, and with a hydrogen / hydrocarbon molar ratio between 0.1:1 and 1:1, and with a WH between 0.5 h 1 and 10 h 1 , preferably between 1 h 1 and 4 h 1 .

[0188] Known catalysts used in isomerization processes generally comprise an alumina support, and from 2% to 10% by weight of chlorine relative to the total weight of the catalyst, and from 0.1% to 0.40% by weight of platinum, expressed as an element, relative to the total weight of the catalyst.

[0189] Maintaining the chlorination rate of the catalyst generally requires the continuous addition of a chlorinated compound, such as carbon tetrachloride, injected in a mixture with the charge of hydrocarbon compounds, typically at a concentration of between 50 and 600 parts per million by weight.

[0190] Dehydration of alcohols and purification (optional)

[0191] In one embodiment of the invention, said olefinic feedstock comes from a unit for dehydrating alcohols, for example ethanol or isobutanol, in particular alcohols from biomass, for example from the fermentation of sugars. This embodiment is illustrated, for example, by [Fig.2a] and [Fig.2b].

[0192] In a particular embodiment shown in [Fig.2a], the C3 and / or C4 alcohol of renewable origin (01) enters a dehydration step (step e) which allows the conversion of said C3 and / or C4 alcohol of renewable origin (01) to obtain a stream enriched in olefins (11) corresponding to, for example, the dehydration of isobutanol into isobutene (also called isobutylene). When a mixture of 4-carbon alcohols is dehydrated, for example a mixture of 1-butanol, 2-butanol and isobutanol, a mixture of four C4 olefins, 1-butene, cis-2-butene, trans-2-butene and isobutene can be formed. The exact concentration in the reaction effluent of each butene isomer is determined by the thermodynamics of the formation of each isomer. To implement the alcohol dehydration step, the reaction conditions and the catalysts used can be tailored to affect the distribution of butene isomers in the product. Thus, mixtures of butenes enriched in a particular isomer can be obtained.

[0193] Dehydration reactions can be carried out in both gas and liquid phase with heterogeneous and homogeneous catalyst systems in many different reactor configurations. Typically, the catalysts used are stable to the water that is generated by the reaction. The water is generally removed from the reaction zone with the product. The resulting olefins exit the reactor in the gas or liquid phase, depending on the reactor conditions, and can be separated and / or purified downstream. The water generated by the dehydration reaction can exit the reactor with unreacted alcohol product(s) and can be separated by distillation or separation.

[0194] Preferably, the olefinic feedstock can be obtained from the dehydration of a renewable isobutanol feedstock. The isobutanol can in particular come from “first generation” “IG” raw materials (cane juice, cane molasses, sugar syrup, etc.) and “second generation” 2G (cellulosic biomass such as straw, bagasse, etc.). Many processes for the dehydration or isomerizing dehydration of alcohols exist.

[0195] According to a variant, the isobutanol dehydration step is carried out as disclosed in patent US9233886 which describes, for example, the dehydration and simultaneous skeletal isomerization of isobutanol in the presence of crystalline silicate catalysts comprising at least 10MR channels, dealuminated or not, modified with phosphorus or not, of the group FER(8 and 10MR channels), MWW(10 and 10MR), EUO(IOMR), MFS(8 and 10MR), ZSM-48(10MR), MTT(IOMR), MFI(10 and 10MR), MEL(IOMR) or TON(IOMR) having a Si / AI ratio greater than 10, silicoaluminophosphate molecular sieves of the group AEL(IOMR), or silica-, zirconia-, titanium- or fluor-alumina on catalysts zeolites. It is known to define the pore size of zeolites by the number of oxygen atoms forming the annular section of the zeolite channels, called "member ring" or MR in English. The process operates with a PPH relative to alcohol of at least 1 h 1 and a temperature of 200 to 600°C.The example is carried out by passing an isobutanol / water charge (weight ratio 95:5) over a powdered FER zeolite of Si / AI 33 at 375°C, 2 bars and at . high PPH (12.6 h1). This variant therefore makes it possible to produce a charge comprising a mixture of n-butenes and isobutene.

[0196] According to another variant, the alcohol dehydration step is carried out as described in patent US8975461. Indeed, this patent describes the production of isobutanol by fermentation and its dehydration to isobutenes on a dehydration catalyst such as acid-treated and untreated alumina (for example, gamma alumina) and silica and clays, including zeolites (for example, beta-type, ZSM-5 or Y-type zeolites), etc. The dehydration reaction typically occurs on a heterogeneous catalyst such as gamma alumina at moderate temperatures (for example, about 250-350°C) and low pressures (for example, less than 1.0 MPa relative). This variant therefore makes it possible to produce a feedstock comprising a mixture of n-butenes and isobutene.

[0197] Step e) of dehydration of alcohols is typically followed by a purification step (step f) which makes it possible to eliminate the oxygenated species. This purification step may be a step of washing the oxygenated species, and / or one or more separation sections and / or one or more adsorption sections of polar species included in the effluent of the dehydration reaction enriched in olefins (represented by the stream (11) in [Fig.2a]) to produce the olefinic effluent (represented by the stream (101) in [Fig.2a]) which will constitute the olefinic feedstock according to the invention. Of course, if step f) is not carried out, then the streams (11) and (101) represented in [Fig.2a] are identical.

[0198] In another particular embodiment presented in [Fig.2b], the olefinic feedstock (101) can be obtained from the dehydration of a renewable ethanol feedstock (02) (step e') producing an ethylene-enriched stream (12).

[0199] The ethanol dehydration step (02) can be carried out in the presence of an amorphous acid catalyst or a zeolitic acid catalyst, as known to those skilled in the art.

[0200] In the case where the catalyst used in the dehydration is a zeolite catalyst, the latter comprises at least one zeolite chosen from zeolites having at least pore openings containing 10 or 12 oxygen atoms (10MR or 12 MR). Preferably, said zeolite catalyst comprises at least one zeolite having a structural type chosen from the structural types MFI, FAU, MOR, FER, and BEA. The zeolite can advantageously be modified by dealumination or desilication according to any dealumination or desilication method known to those skilled in the art. The dehydration of ethanol is advantageously carried out at a temperature between 250°C and 600°C, preferably between 300°C and 600°C and preferably between 300°C and 500°C, at a pressure between 0.1 MPa relative and 5 MPa relative, preferably between 0.1 MPa relative and 2.5 MPa relative and preferably between 0.1 MPa relative and 1 MPa relative and at a PPH of between 0.1 h 1 and 50 h 1 and preferably between 0.5 h 1 and 15 h 1.

[0201] The conversion of the bioethanol feedstock is advantageously greater than 90%, preferably 95% and more preferably greater than 98% by weight. Conversion of the bioethanol feedstock is understood to mean the ratio of the difference between the mass flow rate of the ethanol feedstock (C2H5OH) at the inlet and the mass flow rate of the ethanol feedstock at the outlet to the mass flow rate of the ethanol feedstock at the inlet. The transformation of the feedstock is accompanied by the deactivation of the catalyst by coking and / or by adsorption of inhibiting compounds. The catalyst must therefore periodically undergo a regeneration step.

[0202] Said ethylene-enriched stream (12) during step e') is then optionally purified in step f') to obtain a purified ethylene-enriched stream (22). Step f') makes it possible, for example, to reduce the water and by-product content. This purification step may be a step for washing oxygenated species, and / or one or more separation sections and / or one or more adsorption sections for polar species included in the effluent from the dehydration reaction (12) to produce a purified ethylene stream (22). Of course, if step f') is not carried out, then the streams (12) and (22) shown in [Fig.2b] are identical.

[0203] A dimerization step (step g) of the ethylene (12), optionally purified (22), is necessary before obtaining the olefinic feedstock (101) rich in C4 olefin. This dimerization can be carried out by any method known to those skilled in the art. Dimerization in the presence of a homogeneous or heterogeneous catalyst is possible and known to those skilled in the art.

[0204] As illustrated in [Fig.2b], said stream enriched with purified ethylene (22) is sent to a dimerization step (step g).

[0205] Typically, the olefinic hydrocarbon effluent from the dimerization step g) comprises at least 80% by weight relative to the total mass of olefins contained in said olefinic effluent, of olefins having a number of carbon atoms greater than or equal to 4, in particular, advantageously at least 80% by weight, preferably at least 90% by weight, of olefinic compounds having predominantly a number of carbon atoms between 4 and 8 and less than 20% by weight and preferably less than 10% by weight, of olefinic compounds having predominantly a number of carbon atoms greater than or equal to 9, the weight percentages being expressed relative to the total mass of olefins contained in said olefinic effluent produced.The olefinic effluent obtained is separated to obtain at least said olefinic feed (101) rich in C4 which is sent to the hydrogenation step a) as well as optionally a stream of C6 and C8 olefins (32) and / or optionally a stream of light C2 to C3 olefins (42). Said separation step can advantageously. be implemented by any method known to those skilled in the art such as for example the combination of one or more high and / or low pressure and high and / or low temperature separator flasks, and / or distillation steps comprising one or more distillation columns.

[0206] In a first embodiment, the dimerization is carried out in the presence of a heterogeneous catalyst comprising at least one element from group VIII preferably chosen from nickel, cobalt, iron, platinum and palladium and preferably, said element is nickel and at least one porous oxide refractory support preferably chosen from alumina, silica, silica-aluminas, zirconias, titanium oxide, magnesias, clays taken alone or in a mixture and preferably, said support is an alumina or silica alumina to obtain an olefinic hydrocarbon effluent rich in C4, as described for example in patent FR2959750B1.

[0207] Advantageously, said dimerization advantageously operates at a temperature between 30°C and 400°C, preferably between 50°C and 300°C and preferably between 50°C and 200°C at a relative pressure between 0.5 MPa and 10 MPa, preferably between 1 MPa and 10 MPa and preferably between 1 MPa and 8 MPa and at a VVH between 0.1 h 1 and 10 h 1 and preferably between 0.4 h 1 and 5 h 1.

[0208] In a second embodiment, the catalyst used in the dimerization step is a homogeneous catalyst, that is to say that the catalyst is soluble in the liquid phase composed of dissolved ethylene and its oligomerization products as for example, in the case of the process described in patent FR2959752 allowing the production of kerosene hydrocarbon base from a renewable ethanol feedstock. As regards an implementation by homogeneous catalysis, the person skilled in the art may usefully refer to the teaching of patents US7235703 and US4362650. The homogeneous catalyst advantageously comprises at least one divalent nickel compound, optionally at least one hydrocarbyl-aluminum halide and optionally at least one organic Brônsted acid. Preferably, the catalyst may also contain at least one carboxylic acid anhydride. The catalyst is in liquid form.

[0209] Advantageously, the operating conditions in the reactor(s) carrying out the dimerization step by homogeneous catalysis are such that the temperature is between -20°C and +80°C and the pressure is sufficient to allow the existence of a liquid phase in the reactor(s). Preferably, the absolute total pressure in the reactor(s) is between 2 MPa and 8 MPa.

[0210] Typically, said olefinic effluent produced during the dimerization step may undergo at least one step of treatment of the homogeneous catalytic system and / or at least one step of separation of said effluent.

[0211] By homogeneous catalytic system treatment step is meant a step in which said catalytic system is deactivated and separated from the homogeneous reaction medium and in particular from the olefinic effluent resulting from the oligomerization step. Said optional treatment step of the homogeneous catalytic system is advantageously implemented either:

[0212] - by the use of capture mass,

[0213] - either by treatment with a base and / or an acid,

[0214] - either by the separation of said olefinic effluent neutralized or not by a base, in a first effluent comprising the homogeneous catalytic system and at least a portion of the C9+ olefinic compounds and also a second olefinic effluent free from the catalytic system, said separation being followed by the treatment of the effluent comprising at least a portion of the C9+ compounds and the homogeneous catalytic system by acid and / or basic washing or by the use of capture mass.

[0215] Another subject of the invention relates to a process for producing an alkylate comprising at least:

[0216] a) a step of hydrogenation of at least one mass fraction "1-X" of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVH of between 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising n-paraffins and / or isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1;

[0217] b) an alkylation step of at least:

[0218] - either said at least partially hydrogenated stream comprising n-paraffins and / or isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is strictly greater than 0 and strictly less than 1;

[0219] - either said at least partially hydrogenated stream comprising n-paraffins and / or isobutane when X = 0;

[0220] in admixture with at least a portion of the isobutane formed by isomerization in step d) then separated in step c), in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate,

[0221] c) a separation step comprising at least the following steps:

[0222] - said first effluent comprising an alkylate is sent into a first column to be distilled allowing the recovery of isobutane at the top of said first column and a stream comprising at least the alkylate and n-butane at the bottom of said first column; said isobutane recovered at the top of said first column is recycled upstream of the alkylation step b)

[0223] - said stream comprising at least the alkylate and n-butane at the bottom of said first column is sent to a second distillation column making it possible to recover a flow comprising at least n-butane at the top of said second column and the second effluent comprising said alkylate at the bottom of said second column,

[0224] d) a step of isomerization of the n-butane obtained at the top of said second column at the end of step c) and / or of an additional flow of n-butane to obtain a mixture of isobutane and n-butane which is returned upstream of the first column of step c).

[0225] This particular embodiment is implemented when the olefinic feedstock sent to the hydrogenation has a composition low in isobutene, therefore producing little isobutane during the hydrogenation step. In particular, if the olefinic feedstock comprises n-butenes, these are partially or totally transformed into n-butane during the hydrogenation step a) which are inert in the alkylation step b). In this embodiment, an isobutane feedstock, preferably renewable, is necessary to start the process and constitute the excess isobutane in the reactor. In addition, the process according to the invention according to this embodiment comprises an isomerization unit making it possible to transform butanes resulting from the hydrogenation step into a mixture of isoparaffins and n-paraffins at thermodynamic equilibrium. This isomerization step produces an effluent enriched in isobutane which will be returned to the alkylation step.Preferably, the effluent from isomerization step d) is separated in step c) of separation from the alkylation effluent. Once the isomerization step is started and in production, the external isobutane feed is no longer necessary.

[0226] This isomerization step allows, optionally, in a variant of the process according to the invention to integrate one or more external paraffinic charges.

[0227] Steps a) of hydrogenation, a') of separation (optional), b) of alkylation, c) of separation and d) of isomerization take place under exactly the same operating conditions as described previously.

[0228] In addition, the olefinic feedstock may be produced according to steps e) and f) (optional), and / or e', f') (optional) and g). Product

[0229] The alkylate or bioalkylate obtained preferably comprises at least 60% of 8-carbon paraffins which have a very good octane number (RON Research Octane Number). Said C8 paraffins typically comprise from 70 to 98 mol% of trimethylpentanes (TMP).

[0230] The bioalkylate has a RON greater than 93 and a MON greater than 90. When the alkylation processes C4 feedstocks only, the alkylate or bioalkylate has a RON greater than 93 and a MON greater than 90. Depending on the feedstocks selected, the alkylate or bioalkylate obtained may have a RON greater than 97 and a MON greater than 93, in particular in the case of a feedstock composed solely of isobutane and n-butenes, which makes the alkylate or bioalkylate usable in a mixture with gasoline cuts, or pure for certain applications (old engines, chainsaw, lawnmower, jet ski, etc.). The alkylate obtained is at least partially biosourced with a pMC at least greater than 50%, preferably entirely biosourced with a pMC equal to or greater than 100%.

[0231] In the case where the olefinic feedstock is produced from captured CO2, the alkylate constitutes a recycled carbon fuel (RCF). The pMC can be greater than 0 if the captured CO2 comes from ambient air. However, the alkylate is considered a renewable fuel according to legislation, in particular that of the European Union.

[0232] The alkylate or bioalkylate obtained is free of olefins and aromatics (including benzene) whose content is limited in gasoline. It is free of sulfur and has a low vapor pressure. The properties of this fuel are therefore excellent compared to other gasoline cuts available on the market, in particular those of fossil origin.

[0233] This fuel is free from toxic or carcinogenic compounds when used pure, unmixed.

[0234] This fuel can thus power a gasoline vehicle (but also a lawnmower, chainsaw, jet ski, boat, etc.) without it being necessary to modify the engine.

[0235] The bio-sourced fuel produced by the process according to the invention can however be mixed with fossil gasoline bases in the ecological transition phase (for example reformate, isomerate, naphtha). It will advantageously allow the concentrations of olefins, aromatics or octane number to be adjusted. Examples

[0236] Both examples are implemented as in the process diagram of [Fig.l] and its various variants with regard to the hydrogenation step and alkylation of the olefinic feedstock. Only the nature and origin of the olefinic feedstock varies.

[0237] Example 1 (according to the invention): olefinic feedstock composed mainly of isobutene

[0238] The olefinic feedstock (101) of Example 1 is obtained from the dehydration of a feedstock composed essentially of renewable isobutanol (01) whose mass composition is given in Table 1 below.

[0239] [Tables 1] Renewable isobutanol charge % weight Isobutanol 96 Water 1 C3- alcohols (methanol, ethanol, propanol) 2 C5+ alcohols 1

[0240] The feedstock composed essentially of renewable isobutanol (01) is dehydrated at a relative pressure of 1.2 MPa, in the presence of a solid catalyst based on zeolite (in particular based on beta or Y zeolite or ZSM-5) at a temperature of 375°C, and at a VVH of 0.6 h1. The isobutene-rich effluent is purified to obtain an olefinic feedstock of renewable origin (101) composed of a mixture of isobutene, C3- olefins (ethylene, propylene) and C5+ olefins in proportions equivalent to those of the feedstock (each alcohol is transformed into the corresponding alkene). The olefinic feedstock is therefore composed essentially of isobutene (96% by weight) and butenes (3% by weight). In this example, X=0. The entire olefinic feedstock rich in isobutene (101) is sent to a partial hydrogenation step a) at a pressure of 2.8 MPa relative, in the presence of the solid catalyst LD485 marketed by Axens, at a temperature of 60°C, and at a VVH of 2 h '.The amount of hydrogen is adjusted to have a hydrogenation rate of 54% and obtain a partially hydrogenated stream (104). This said partially hydrogenated stream (104) is then sent to a separation step a') to remove the light compounds Cl and / or C2 and obtain a mixture rich in stabilized isobutane / isobutene (111).

[0241] The molar composition of the mixture rich in isobutane / stabilized isobutene (111) is presented in Table 2 below.

[0242] [Tables2] Compounds Molar composition (%) Propane 0.17% Isobutane 51.59% n-Butane 3.40% Isobutene 43.08% Isopentane 0.07% n-Pentane 0.00% C5 Olefins 1.69%

[0243] The mixture rich in isobutane / stabilized isobutene (111) is sent to the alkylation step b) in the presence of sulfuric acid at 94.5% by weight, at a temperature of 4.4°C, at a pressure of 0.05 MPa relative, and an isobutane / olefins ratio in the alkylation reactor of 10 / 1 by volume to obtain a first effluent comprising an alkylate (201).

[0244] The propane in the feedstock is inert in the alkylation reactor. It is purged into one of the drums in the alkylation reaction section at the refrigeration loop.

[0245] Referring to [Fig. 3], said first effluent comprising an alkylate (201) is sent to a deisobutanizer making it possible to recover the isobutane at the top of the column (212), which is recycled to the inlet of the alkylation step a). The stream comprising at least the alkylate and n-butane recovered at the bottom of the deisobutanizer is then sent to a debutanizer making it possible to recover the stream of n-butane at the top of said debutanizer (302), which can be recovered outside the unit and the alkylate at the bottom of the debutanizer (211).

[0246] The alkylate obtained was produced from 100% renewable source and has a pMC greater than 100%, a RON of 93.3, a MON of 91.9 and a density of 0.706 kg / m3. The alkylate obtained comprises 62.5 mol% of C8 isoparaffins, in particular 54 mol% of trimethylpentane “TMP” and 8.5 mol% of DimethylHexane “DMH”. The alkylate also comprises 18.3 mol% of C9+ isoparaffins and 19.1 mol% of lighter fractions (C5, C6 and C7 isoparaffins).

[0247] In the implementation of Example 1, with a renewable feedstock composed essentially of isobutene, the yield of the alkylation in alkylate is 95% by weight relative to the mixture rich in isobutane / stabilized isobutene entering into the alkylation. This yield is close to an alkylation on more conventional non-biosourced feedstocks or even much better, depending on the feedstocks. Indeed, in this example, there are no normal paraffins in the alkylation feedstock, unlike typical fossil feedstocks.

[0248] At the end of the alkylation step, from 1 kg of renewable isobutanol, approximately 695 g of renewable alkylate is produced.

[0249] At the end of the alkylation step, from 1 kg of renewable olefinic feedstock, approximately 950 g of renewable alkylate is produced.

[0250] Example 2 (according to the invention): olefinic feedstock composed of a butene / isobutene mixture

[0251] In example 2, the olefinic feedstock is composed essentially of a mixture of n-butene and isobutene (101) whose mass composition is that of table 3 below.

[0252] [Tables3] Compound Mass composition (%) Butane 0.4 Ethylene 0.6 Propylene 0.2 Isobutene 41.5 Nbutene 56.7 Olefins with at least 5 C atoms 0.6

[0253] The olefinic feedstock composed of a mixture of isobutene and butene of renewable origin (101) is sent entirely to a partial hydrogenation step a) at a pressure of 2.8 MPa relative, in the presence of an LD485 catalyst marketed by Axens, at a temperature of 60°C, and at a VVH of 2 h1. The quantity of hydrogen is adjusted to have a hydrogenation rate of 54% to obtain a partially hydrogenated effluent (104).

[0254] No fraction bypasses the hydrogenation step, i.e. X=0.

[0255] The partially hydrogenated effluent (104) is sent to a separation step a') to remove the light compounds of type Cl and / or C2 and obtain a stabilized paraffin / olefin mixture (111). The molar composition of the stabilized paraffin / olefin mixture (111) is presented in Table 4:

[0256] [Tables4] Composition % molar Propane 0.14% Isobutane 22.78% n-Butane 31.39% Isobutene 19.01% Butene-1 2.03% Trans-2-Butene 16.79% Cis-2-Butene 7.26% Isopentane 0.02% n-Pentane 0.00% C5 Olefins 0.57%

[0257] The stabilized paraffin / olefin mixture (111) is sent to the alkylation step b) in the presence of 94.5% by weight sulfuric acid, at a temperature of 4°C, at a pressure of 0.05 MPa relative, and an isobutane / olefin ratio at the inlet of the alkylation step of 10 / 1 by volume to obtain a first effluent comprising an alkylate (201).

[0258] This ratio was adjusted thanks to the composition of the stabilized paraffin / olefin mixture (111) via the hydrogenation rate but also with the flow rate of the recycled stream (212).

[0259] Indeed, said first effluent comprising an alkylate (201) is sent to a deisobutanizer making it possible to recover the isobutane at the top of the column (212), which is recycled to the inlet of the alkylation step a). The stream comprising at least the alkylate and n-butane recovered at the bottom of the deisobutanizer is then sent to a debutanizer making it possible to recover a stream comprising n-butane (inert to alkylation) at the top of said debutanizer (302) and the alkylate at the bottom of the debutanizer (211).

[0260] Indeed, the stabilized paraffin / olefin mixture (111) comprises 31% n-butane. An isomerization step (step c) therefore makes it possible to upgrade this cut in order to partially transform this cut into isobutane, thus increasing the yield of the process according to the invention.

[0261] The stream comprising n-butane at the top of said debutanizer (302) is sent to an isomerization step at a pressure of 3.0 MPa, a temperature of 160°C, a PPH of 1.4 h1, and in the presence of a platinum-on-chlorinated alumina catalyst ATIS1L marketed by Axens in order to obtain an effluent enriched in isobutane (303) at thermodynamic equilibrium (60% isobutane, 40% n-butane). The effluent from the isobutane-enriched isomerization step (303) is then returned to the fractionation section, in particular to the deisobutanizer to recover the isobutane at the top of column (212) and recycle it to the alkylation step b).

[0262] The alkylate obtained was produced from 100% renewable source and has a pMC greater than 100%, a RON of 96.1, a MON of 93.7 and a density of 0.706 kg / m3.

[0263] The alkylate obtained comprises 76 mol% of C8 isoparaffins, in particular 66% in mole of trimethylpentane “TMP” and 10 mole% of DimethylHexane “DMH”. The alkylate also includes 12.3 mole% of C9+ isoparaffins and 11.7 mole% of lighter fractions (C5, C6 and C7 isoparaffins).

[0264] In the implementation of Example 2, with a renewable feedstock composed of an n-butene / isobutene mixture, the alkylation yield is 96% by weight of alkylate relative to the stabilized paraffin / olefin mixture. However, this example required the addition of the optional isomerization step. This yield is close to alkylation on more conventional non-biosourced feedstocks, integrating an isomerization unit, or even much better, depending on the feedstocks.

[0265] The process according to the invention, illustrated by examples 1 and 2, makes it possible in particular to produce a bio-sourced gasoline or a bioalkylate having the following advantages: - its composition is essentially paraffinic with a high octane number with a RON greater than 93; and a MON greater than 90;

[0266] - this gasoline is free of olefins and aromatics (including benzene) whose content is limited in gasoline;

[0267] - this gasoline is sulfur-free and has a low vapor pressure. The properties of this fuel are therefore excellent compared to other gasoline blends available on the market, particularly those of fossil origin;

[0268] - this essence is free from toxic or carcinogenic compounds, when it is used pure, not mixed;

[0269] - this gasoline can power a gasoline vehicle (but also a lawnmower, chainsaw, jet ski, boat, etc.) without having to modify the engine;

[0270] - the use of pure fuel means that it does not need to be mixed with one or more fossil fuel bases emitting greenhouse gases, or toxic gases or including carcinogenic compounds such as, for example, aromatic or olefinic compounds.

Claims

Claims

1. Process for producing an alkylate comprising at least: a) a step of hydrogenation of at least one mass fraction “1-X” of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVHbetween 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1; b) an alkylation step of at least: - either said at least partially hydrogenated stream comprising isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is greater than strictly 0 and strictly less than 1; - or said at least partially hydrogenated stream comprising isobutane when X = 0; in the presence of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 MPa relative and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate.

2. A method according to claim 1, wherein said first effluent comprising an alkylate is sent to at least one separation step c) to obtain at least one second effluent comprising said alkylate and at least one third effluent comprising isobutane, characterized in that said third effluent comprising isobutane is recycled upstream of the alkylation step b).

3. Method according to claim 2, in which said separation step c) is characterized by the following sequence: - said first effluent comprising an alkylate is sent to a first distillation column making it possible to recover the isobutane at the top of said first column and a stream comprising at least the alkylate and n-butane at the bottom of said first column; - said stream comprising at least the alkylate and n-butane at the bottom of said first column is sent to a second distillation column making it possible to recover a stream comprising at least n-butane at the top of said second column and the second effluent comprising said alkylate at the bottom of said second column.

4. A process according to any preceding claim, wherein said olefinic feed comprises at least 90% by weight of C4 olefins relative to the total weight of said feed.

5. The process of claim 4, wherein said olefinic feedstock comprises at least 90% by weight of isobutene relative to the total weight of said olefinic feedstock.

6. Process according to any one of the preceding claims, in which the hydrogenation of the mass fraction “1-X” of said olefinic feedstock is total, it being understood that X is strictly greater than 0 and strictly less than 1.

7. A process according to any one of the preceding claims, wherein a first additional stream, preferably of renewable origin, comprising isobutane is sent to the alkylation step b) and / or to the separation step c).

8. Process according to any one of the preceding claims, in which a step a') of separation of the C1 and C2 hydrocarbon compounds is carried out between the step a) of hydrogenation and the step b) of alkylation.

9. A process according to any preceding claim, wherein said olefinic feedstock is derived 100% from renewable sources.

10. A process according to any preceding claim, wherein said olefinic feedstock is derived from alcohols of renewable origin, or from biomass, or from a Fischer-Tropsch unit or from a mixture of several renewable sources.

11. A process according to any one of the preceding claims, wherein said olefinic feedstock is obtained by dehydration of C3 and / or C4 alcohols of renewable origin.

12. A process according to claim 11, wherein said olefinic feedstock is obtained by dehydration of n-butanol and / or isobutanol.

13. Process according to any one of claims 1 to 10, wherein said olefinic feedstock is obtained from C2 alcohol of renewable origin obtained according to the following steps: - a step of dehydration of C2 alcohol of renewable origin to produce a C2 olefinic feedstock; - a step of dimerization of said C2 olefinic feedstock to obtain a C4 olefinic feedstock.

14. A process according to any one of claims 3 to 13, wherein the n-butane separated at the top of said second distillation column is sent to an isomerization step d) to isomerize the n-butane and obtain a mixture of isobutane and n-butane which is returned to the separation step c).

15. A process according to any preceding claim, wherein a second additional stream comprising n-butane is fed into an isomerization step d) to obtain a stream comprising a mixture of isobutane and n-butane which is then fed into separation step c).

16. Process for producing an alkylate comprising at least: a) a step of hydrogenation of at least one mass fraction “1-X” of an olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins at a pressure of between 1.8 MPa and 6.0 MPa relative, in the presence of hydrogen and a solid catalyst, at a temperature of between 50°C and 150°C, and at a VVHbetween 0.5 h 1 and 4.0 h 1 to obtain an at least partially hydrogenated stream comprising n-paraffins and / or isobutane; it being understood that X is greater than or equal to 0 and strictly less than 1; b) an alkylation step of at least: - either said at least partially hydrogenated stream comprising n-paraffins and / or isobutane obtained at the end of step a) and a mass fraction “X” of the olefinic feedstock at least partly of renewable origin comprising C3 to C4 olefins, it being understood that X is greater than strictly 0 and strictly less than 1; - or said at least partially hydrogenated stream comprising n-paraffins and / or isobutane when X = 0; in a mixture with at least a portion of the isobutane formed by isomerization in step d) and then separated in step c), in the presence.

17. of an acid catalyst in liquid or solid form, at a temperature between -3°C and 90°C, at a pressure between 0.01 and 2.0 MPa relative, and an isobutane / olefins ratio in the alkylation reactor between 8 / 1 and 20 / 1 by volume, to obtain a first effluent comprising an alkylate, c) a separation step comprising at least the following steps: - said first effluent comprising an alkylate is sent to a first distillation column making it possible to recover the isobutane at the top of said first column and a stream comprising at least the alkylate and n-butane at the bottom of said first column; said isobutane recovered at the top of said first column is recycled upstream of the alkylation step b) - said stream comprising at least the alkylate and n-butane at the bottom of said first column is sent to a second distillation column making it possible to recover a stream comprising at least n-butane at the top of said second column and the second effluent comprising said alkylate at the bottom of said second column, d) a step of isomerization of the n-butane obtained at the top of said second column at the end of step c) and / or of an additional stream of n-butane to obtain a mixture of isobutane and n-butane which is returned upstream of the first column of step c). Alkylate obtained by the process according to any one of claims 1 to 15, characterized in that its modern carbon content measured according to standard ASTM D 6866-21 is greater than 50, preferably greater than or equal to 100.

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