Method for hydrotreating and hydroisomerising vegetable oil in one step using at least one sulphide catalyst with a bea-structure zeolite alone or mixed with a fau-structure zeolite

Abstract

The present invention discloses a method for treating a feedstock originating from a renewable source, the method comprising: a) a step of hydrotreating the feedstock in the presence of at least one fixed-bed catalyst, the catalyst comprising a hydrogenating function and an oxide support; b) a step of hydroisomerising at least one portion, and preferably all, of the hydrocarbon liquid effluent resulting from step a) in the presence of a bifunctional fixed-bed hydroisomerisation catalyst, the catalyst comprising a sulphide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising a BEA-structure zeolite alone or mixed with a FAU-structure zeolite and at least one binder; and c) a step of fractionating the effluent resulting from step b) to obtain at least one gas oil fraction.

Description

[0001] PROCESS FOR THE HYDROTREATMENT AND HYDROISOMERIZATION OF VEGETABLE OIL IN A SINGLE STAGE USING AT LEAST ONE SULFIDE CATALYST WITH A ZEOLITE OF STRUCTURAL TYPE BEA ALONE OR IN MIXTURE WITH A ZEOLITE OF STRUCTURAL TYPE FAU

[0002] Field of invention

[0003] The search for new sources of renewable energy for fuel production is a major challenge in both meeting fuel demand and taking into account concerns related to the environment and the decarbonization of the road and air transport sectors.

[0004] In this respect, the recovery of feedstocks from renewable sources into fuels has seen a resurgence of interest in recent years. Examples of these feedstocks include vegetable oils such as rapeseed or soybean oil, animal fats, used cooking oils, and mixtures of such feedstocks. These feedstocks contain chemical structures such as triglycerides, esters, or fatty acids. The fatty chains consist of a hydrocarbon structure of variable chain length and generally and predominantly comprise 16 to 18 carbon atoms. Other types of feedstocks containing fatty acids, such as tall oil feedstocks from the paper industry, can also be mentioned.

[0005] One possible route is the catalytic transformation of these feedstocks from renewable sources by hydrotreatment (in the presence of hydrogen) into deoxygenated paraffinic fuel. Many metal or sulfide catalysts are known to be active for this type of reaction. Depending on the length of the hydrocarbon chains, the linear paraffins obtained are compatible in terms of boiling points with the hydrocarbons present in fossil diesel and kerosene fuel bases.

[0006] These processes for hydrotreating feedstock from renewable sources are already well known and are described in numerous patents. Examples include patents: US 4,992,605, US 5,705,722, EP 1,681,337 and EP 1,741,768. Transition metal sulfide catalysts enable the production of linear paraffins by transforming oxygenated compounds using two reaction pathways:

[0007] - hydrodeoxygenation (HDO) leading to the formation of water by consumption of hydrogen and to the formation of hydrocarbons with carbon number (C n ) equal to that of the initial fatty acid chains,

[0008] - decarboxylation / decarbonylation (DCO) leading to the formation of carbon oxides (carbon monoxide and dioxide: CO and CO2) and the formation of hydrocarbons with one less carbon (C n -i) compared to the initial fatty acid chains.

[0009] This transformation also leads to the formation of by-products such as propane (from the glyceric structure of fatty substances) and methane (by methanation reaction of carbon oxides under hydrotreatment conditions).

[0010] The liquid effluent from these hydrotreatment processes, after gas separation, consists essentially of n-paraffins and is substantially free of sulfur, nitrogen and oxygen impurities. This effluent has a sulfur content typically between 1 and 20 ppm by weight, a nitrogen content generally between 0.2 and 30 ppm by weight and an oxygen content generally less than 2000 ppm by weight. The paraffins have a carbon atom number typically between 9 and 25, which is mainly dependent on the composition of the fatty acid chain distribution of the renewable feedstock to be hydrotreated.

[0011] However, this liquid effluent cannot generally be incorporated as is into the kerosene or diesel pool because it does not directly meet all the fuel specifications, for example due to insufficient cold properties and / or boiling temperatures that are too high. Indeed, the linear paraffins present lead to high pour points and therefore to freezing phenomena for uses at low temperatures. For example, eicosane (linear paraffin with 20 carbon atoms, C20H42) has a boiling point of 340°C and a melting point of 37°C. The boiling point of eicosane is therefore compatible with incorporation into a diesel pool but its melting temperature can generate freezing problems and limit its use. As an illustration, the filterability limit temperature for winter diesel is a maximum of -15°C for regulations in France (standard EN590).Furthermore, the boiling temperature of eicosane makes it unincorporable into the kerosene pool, for which the final temperature of the D86 distillation curve must be less than 300°C (ASTM D1655 standard).

[0012] Depending on the type of fuel (kerosene or diesel) and the fuel specifications, it may be necessary to carry out an additional hydroconversion step (hydroisomerization and / or hydrocracking reactions) to transform the linear paraffins in the hydrotreated liquid effluent. Hydroisomerization converts a linear paraffin into a branched paraffin while preserving the number of carbon atoms in the molecule. This improves the cold properties of the effluent because branched paraffins have better cold properties and a lower boiling point than the corresponding linear paraffins with the same number of carbon atoms. For example, nonadecane has a melting point of 32°C, while one of its monobranched isomers, 7-methyl-octadecane, has a melting point of -16°C. Hydrocracking converts linear paraffin into lower molecular weight linear or branched paraffins.This allows the distillation curve of the effluent to be adjusted as needed to make it compatible with the kerosene pool, which has more stringent cold property and maximum boiling point specifications. For example, hydrocracking one eicosane molecule can produce two 2-methylnonane molecules. The boiling point of 2-methylnonane is 167°C, which is compatible with incorporation into the kerosene pool in terms of boiling point. The hydroconversion step is carried out on a bifunctional catalyst with both a hydro / dehydrogenating function and a Bronsted acid function. The operating conditions can be adapted to favor hydroisomerization or hydrocracking reactions as needed. In all cases, it is desirable to minimize the production of cracking products that are too light and cannot be incorporated into the kerosene and diesel cuts, in order to maximize their yield.

[0013] The appropriate choice of the acid phase promotes the isomerization of long linear paraffins and minimizes cracking. Thus, the shape selectivity of medium-pore (10 MR) or large-pore (12 MR) zeolites makes their use particularly suitable for obtaining catalysts selective for isomerization and hydroconversion. Other acid phases of the zeolitic or non-zeolitic type such as halogenated aluminas (chlorinated or fluorinated in particular), phosphorus-containing aluminas, silica-aluminas or silica-containing aluminas can also be used. However, it is well known that factors other than the acid phase have an impact on the activity and selectivity of a bifunctional catalyst. The hydroisomerization and hydrocracking of normal paraffins have thus been the subject of numerous academic studies since the original work of the sixties by Weisz (Weisz P, Adv catal 1962, 13, 137) or Coonradt and Garwood (HL Coonradt, W.E. Garwood Ind. Eng. Chem. Process Des. Dev., 3 (1 ) (1964), pp. 38-45).

[0014] The most commonly accepted mechanism involves first dehydrogenating the n-paraffin to an n-olefin at a hydrodehydrogenating site and then, after diffusion to a Bronsted acid site, protonating it to a carbenium ion. After structural rearrangement and / or p-scission, the carbenium ions desorb from the acid phase as olefins after deprotonation. Then, after diffusion to a hydrodehydrogenating site, the olefins are hydrogenated to form the final reaction products. It is then necessary to have a sufficiently active hydro / dehydrogenating function with respect to the acid function to, on the one hand, rapidly supply the acid phase with olefins and, on the other hand, to rapidly hydrogenate the olefinic intermediates after their reaction on the acid phase.This allows on the one hand to maximize the activity of the catalyst and on the other hand to maximize the production of isomerized paraffins by limiting overcracking towards light hydrocarbons. The use of a sufficiently active hydrogenating function is also desirable in order to limit the deactivation of the bifunctional catalyst by coking during the hydroconversion of n-paraffins (Alvarez et al., Journal of Catalysis, 162, 2, 179-189) for a range of fixed operating conditions.

[0015] Noble metals (Pt, Pd) or group VIB transition metals (Mo, W) combined with group VIII transition metals (Ni, Co) can act as hydro / dehydrogenating functions for the catalyst. Noble metals are used in their reduced form, while group VIB and VIII transition metals are used in a sulfurized form.

[0016] The choice of the nature of the hydro / dehydrogenating function, of the noble metal or transition metal sulfide type, depends on different criteria, of an economic nature (the price of noble metals is significantly higher than that of transition metals from groups VIB and VIII) or of the nature of the feedstock to be converted (impact of the presence of contaminants). Thus, the hydro / dehydrogenating activity of noble metals is higher than that of transition metal sulfides when the partial pressure of hydrogen sulfide (H2S) in the reaction medium is low or even zero. Patent application US8809610 claims a process for the production of paraffinic hydrocarbons from a feedstock containing triglycerides, diglycerides, monoglycerides and / or fatty acids.Said method comprises (a) a step of hydrodeoxygenation in the presence of hydrogen and a catalyst in order to obtain an effluent comprising water and paraffins, (b) a step of separation of the effluent resulting from (a) to obtain a liquid effluent rich in paraffins and (c) a step of hydroisomerization of said effluent rich in paraffins in the presence of hydrogen and a catalyst comprising nickel sulfide and tungsten and / or molybdenum sulfide as hydrogenating phases and a support comprising silica-alumina and / or a zeolite. It is taught that the use of sulfide phases instead of noble metals as hydrogenating phases makes it possible not to have to completely eliminate the impurities from the effluent resulting from step (a).

[0017] Patent US8039682 describes a process for producing kerosene from a renewable feedstock, comprising a step of hydrotreatment, isomerization and selective hydrocracking in the presence of a multifunctional catalyst or a series of catalysts, a step of gas / liquid separation of the effluent obtained followed by a fractionation step to produce a jet effluent, naphtha and a residual effluent heavier than the jet, then the recycling of this residual effluent in the reaction zone with a recycle rate relative to the fresh feedstock of between 0.1 and 8. The deoxygenation and hydrogenation function of the catalyst or series of catalysts that can be used in the process according to the invention can be provided by a noble metal such as platinum, palladium, rhodium and ruthenium or by sutured metals such as a sulfurized NiMo or sulfurized NiW active phase.The isomerization and selective hydrocracking function can be provided by a zeolite such as, for example, 10-12MR zeolites such as zeolites of structural type BEA, MOR, MFI or FAU or by an amorphous silica alumina. The patent cites numerous examples of catalysts that can be used in the process according to the invention: a Pt-based catalyst dispersed on a support comprising a Y zeolite, a catalyst comprising Pt and Pd on a support comprising a Y zeolite and amorphous silica alumina. In another embodiment, a catalyst comprising Pt and / or Pd on a Y zeolite, ZSM-5, an amorphous silica alumina, MOR, SAPO-11 and / or SM3 can be used to catalyze all types of reaction. In another embodiment, a catalyst comprising a sulfurized NiMo phase on a Y zeolite, ZSM-5, an amorphous silica alumina, MOR, SAPO-11 and / or SM3' may also be used.A catalyst series can also be a sequence of sulfurized NiMo supported on amorphous silica-alumina followed by a Pt-based catalyst supported on amorphous silica-alumina. Many other deoxygenation and selective isomerization and hydrocracking catalysts are also mentioned. For example, a long list of hydrocracking / isomerization catalysts is cited and includes a Group VIII metal such as Pt and / or Pd, and a support which may be amorphous or crystalline, said support may include aluminas, amorphous silica alumina, and ferrierite-type zeolites, ALPO-31, SAPO-11, SAPO-31, SAPO-37, SAPO-41, SM-3, MgAPSO-31, FU-9, NU-10, NU-23, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50, ZSM-57, MeAPO-11, MeAPO-31, MeAPO-41, MeAPSO-11, MeAPSO-31, MeAPSO-41, MeAPSO-46, ELAPO-II, ELAPO-31, ELAPO-41, ELAPSO-I I, ELAPSO-31, ELAPSO-41.This patent also teaches that it would be possible to carry out the hydroisomerization and hydrocracking step without prior elimination of the water and carbon oxides generated during the hydrotreatment step. The example of the patent actually reports the sequence of two catalysts without specifying their nature and the presence of zeolite.

[0018] This effect is confirmed by Brosius et al (R. Brosius, PJ Kooyman, JCQ Fletcher, ACS Catal. 2016, 6, 7710) who are interested in the hydrocracking reaction of n-hexadecane on a Pt catalyst supported on an MFI type zeolite, ZSM-5, in the presence of large quantities of water (generated in situ by dehydration of ethanol). It shows that the presence of water strongly reduces the activity of the catalyst, but underlines a beneficial effect on the selectivity: the secondary cracking observed on the catalyst using a ZSM-5 zeolite is suppressed, only the primary cracking takes place, moreover the isomerization is also reduced, thus favoring the production of linear alkanes. The mode of action invoked is an adsorption competition between hydrocarbons and water on the hydrophilic acid sites. Thus, this study shows a drastic modification of the activity and selectivity by adding water to the reaction system.

[0019] In attempting to develop a process for treating feedstocks from renewable sources to produce middle distillates, the applicant has demonstrated that a sequence of at least one hydrotreatment step of said feedstock followed by a hydroisomerization step in a single step (i.e. without any intermediate separation of the effluent from the hydrotreatment step) makes it possible to obtain an activity of said catalyst improved by the use of a specific hydroisomerization catalyst comprising a sulfide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising at least one zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one binder, while maintaining high yields of middle distillates and preferably of diesel cut,compared to the use of catalysts conventionally used in the prior art in a one-step process.,

[0020] Obtaining a high catalytic activity of the hydroisomerization catalyst makes it possible, for example, to increase the lifetime of the catalyst and to limit the frequency of replacement of the fresh catalyst.

[0021] Another advantage of the present invention is to provide a process operating in one stage comprising a single fractionation zone for the effluent from the hydroisomerization stage, more economical than a process operating in two stages, while allowing a high yield to be obtained in the middle distillate cut and preferably in the renewable diesel cut.

[0022] Another advantage of the process according to the invention is that it allows the use of existing hydrotreatment units without significant investment.

[0023] For the purposes of the present invention, the various embodiments presented can be used alone or in combination with each other, without limitation of combination.

[0024] For the purposes 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, for the purposes of the present invention, a preferred range of pressure values ​​may be combined with a more preferred range of temperature values.

[0025] In the following text, the groups of chemical elements are given 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 VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification, and group VIB to the metals of column 6.

[0026] In the remainder of the text, the expressions "between ... and ..." and "between .... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention. In the present description, the expression "greater than ..." is understood as strictly greater, and symbolized by the sign ">", and the expression "less than" as strictly less, and symbolized by the sign "<".

[0027] Subject of the invention

[0028] More specifically, the present invention relates to a process for treating a feedstock from a renewable source comprising at least: a) a step of hydrotreating said feedstock in the presence of at least one fixed-bed catalyst, said hydrotreatment catalyst comprising a hydrogenating function and an oxide support, at a temperature of between 200 and 450°C, at a pressure of between 1 MPa and 10 MPa, at an hourly space velocity of between 0.1 h -1 and 10 a.m. -1 and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 70 and 1700 Nm 3 hydrogen / m 3of charge, b) a step of hydroisomerization of the entire hydrocarbon liquid effluent from step a) in the presence of a bifunctional fixed-bed hydroisomerization catalyst, said catalyst comprising a sulfide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising a zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one binder, said hydroisomerization step being carried out at a temperature of between 250°C and 500°C, at a pressure of between 1 MPa and 10 MPa, at an hourly space velocity of between 0.1 and 10 h -1 and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 70 and 1500 Nm 3 / m 3 of charge, c) a step of fractionation of the effluent from step b) to obtain at least one diesel fraction.

[0029] In a preferred embodiment, the hydrotreatment step a) and hydroisomerization step b) are carried out in a single step, the process according to the invention not comprising an intermediate separation step between step a) and step b). Detailed description of the invention

[0030] Charges

[0031] The present invention is particularly dedicated to the preparation of diesel fuel bases and possibly kerosene fuel bases corresponding to new environmental standards, from charges from renewable sources.

[0032] The feedstocks from renewable sources used in the process according to the present invention are advantageously chosen from oils and fats of vegetable or animal origin, or mixtures of such feedstocks, containing triglycerides and / or free fatty acids and / or esters. The vegetable oils may advantageously be crude or refined, totally or partially, and derived from the following plants: rapeseed, sunflower, soybean, palm, palm kernel, olive, coconut, jatropha, this list not being exhaustive. Algae or fish oils are also relevant. The animal fats are advantageously chosen from lard or fats composed of residues from the food industry or from the catering industries.

[0033] These fillers essentially contain triglyceride-type chemical structures that the skilled person also knows as fatty acid triester as well as free fatty acids. A fatty acid triester is thus composed of three fatty acid chains. These fatty acid chains in the form of triester or in the form of free fatty acids, have a number of unsaturations per chain, also called the number of carbon-carbon double bonds per chain, generally between 0 and 3 but which can be higher, particularly for oils derived from algae which generally have a number of unsaturations per chain of 5 to 6.

[0034] The molecules present in the fillers from renewable sources used in the present invention therefore have a number of unsaturations, expressed per triglyceride molecule, advantageously between 0 and 18. In these fillers, the level of unsaturation, expressed as the number of unsaturations per hydrocarbon fatty chain, is advantageously between 0 and 6.

[0035] Renewable feedstocks generally also contain various impurities, including heteroatoms such as nitrogen. Nitrogen levels in vegetable oils or animal fats are generally between approximately 1 ppm and 100 ppm by weight, depending on their nature. Other types of feedstocks containing fatty acids, such as tall oil feedstocks from the paper industry, can also be mentioned.

[0036] Process and catalysts

[0037] Advantageously, the feedstock may undergo, prior to step a) of the process according to the invention, a pre-treatment or pre-refining step so as to eliminate, by appropriate treatment, contaminants such as metals, such as alkaline compounds, for example on ion exchange resins, alkaline earths and phosphorus. Suitable treatments may, for example, be thermal and / or chemical treatments well known to those skilled in the art.

[0038] In accordance with step a) of the process according to the invention, the feedstock, optionally pretreated, is brought into contact with at least one fixed-bed hydrotreatment catalyst at a temperature of between 200 and 450°C, preferably between 220 and 350°C, preferably between 220 and 320°C, and even more preferably between 220 and 310°C. The pressure is between 1 MPa and 10 MPa, preferably between 1 MPa and 6 MPa and even more preferably between 1 MPa and 4 MPa. The hourly space velocity, i.e. the volume of feedstock per volume of catalyst per hour, is between 0.1 h -1 and 10 a.m. 1 The charge is brought into contact with the catalyst in the presence of hydrogen. The total quantity of hydrogen mixed with the charge is such that the hydrogen / charge ratio is between 70 and 1700 Nm 3 hydrogen / m 3 load and preferably between 150 and 1500 Nm 3 hydrogen / m 3 dump.

[0039] In step a) of the process according to the invention, the fixed-bed hydrotreatment catalyst advantageously comprises at least one metal from group VIII and / or group VIB, taken alone or as a mixture, and a support chosen from the group formed by alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. This support may also advantageously contain other compounds and, for example, oxides chosen from the group formed by boron oxide, zirconia, titanium oxide and phosphoric anhydride. The preferred support is an alumina support, and very preferably alumina r], Ô OR y.

[0040] Said hydrotreatment catalyst is advantageously a catalyst comprising metals from group VIII preferably chosen from nickel and cobalt, taken alone or in a mixture, preferably in association with at least one metal from group VIB preferably chosen from molybdenum and tungsten, taken alone or in a mixture.

[0041] The content of metal oxides of groups VIII and preferably nickel oxide is advantageously between 0.5 and 10% by weight of nickel oxide (NiO) and preferably between 1 and 5% by weight of nickel oxide and the content of metal oxides of groups VIB and preferably molybdenum trioxide is advantageously between 1 and 35% by weight of molybdenum oxide (MOO3), preferably from 5 to 30% by weight, the percentages being expressed in % by weight relative to the total mass of the catalyst.

[0042] The total content of metal oxides from groups VIB and VIII in the catalyst used in step a) is advantageously between 5 and 45% by weight and preferably between 6 and 35% by weight relative to the total mass of the catalyst.

[0043] Said hydrotreatment catalyst used in step a) of the process according to the invention may be chosen so as to orient the selectivity of the reaction as much as possible towards a hydrogenation conserving the number of carbon atoms of the fatty chains, i.e. the hydrodeoxygenation (HDO) route, in order to maximize the recovery of the renewable feedstock in fuel cuts and the yield of hydrocarbons entering the distillation field of kerosenes and / or diesel fuels and thus limit the loss of carbon in the form of carbon oxides and methane. This is why, preferably, the operation is carried out at a relatively low temperature. Maximizing the hydrogenating function also makes it possible to limit the polymerization and / or condensation reactions leading to the formation of coke which would degrade the stability of the catalytic performances.

[0044] Said catalyst used in hydrotreatment step a) of the process according to the invention may also advantageously contain a doping element chosen from phosphorus and boron, taken alone or in a mixture and preferably phosphorus. Said doping element may be introduced into the matrix or preferably be deposited on the support. Silicon may also be deposited on the support, alone or with phosphorus and / or boron and / or fluorine.

[0045] The weight content of oxide of said doping element is advantageously less than 20% and preferably less than 10% and is advantageously at least 0.001%.

[0046] The metals of the catalysts used in hydrotreatment step a) of the process according to the invention are sulphide metals or metallic phases and preferably sulphide metals. It would not be outside the scope of the present invention to use in step a) of the process according to the invention, simultaneously or successively, a single catalyst or several identical or different catalysts. This step can be carried out industrially in one or more reactors with one or more catalytic beds.

[0047] Said hydrotreatment step a) allows the hydrodeoxygenation, hydrodenitrogenation and hydrodesulfurization of said feed.

[0048] In accordance with step b) of the process according to the invention, at least a portion and preferably all of the effluent from step a) of the process according to the invention is converted in the presence of a fixed-bed bifunctional hydroisomerization catalyst, said catalyst comprising a sulfide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising a zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one binder, said hydroisomerization step being carried out at a temperature of between 250 and 500°C, at a pressure of between 1 MPa and 10 MPa, at an hourly space velocity of between 0.1 and 10 h -1 and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 70 and 1500 Nm 3 / m 3 dump.

[0049] The operating conditions of the hydroisomerization step b) are adjusted to promote the hydroisomerization and / or hydrocracking reactions. Preferably, the hydroisomerization step b) of the process according to the invention operates at a temperature of between 250°C and 450°C, and very preferably, between 250 and 400°C, at a pressure of between 2 MPa and 10 MPa and very preferably, between 1 MPa and 9 MPa, at an hourly volumetric flow rate advantageously of between 0.2 and 7 h -1 and very preferably, between 0.5 and 5 h -1 , at a hydrogen flow rate such that the hydrogen / charge volume ratio is advantageously between 100 and 1000 normal m 3 of hydrogen per m 3 load and preferably between 150 and 1000 normal m 3 of hydrogen per m 3 dump.

[0050] According to the invention, the hydroisomerization catalyst is a bifunctional catalyst comprising a sulfide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising a zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one oxide binder. Said hydroisomerization catalyst is advantageously a catalyst comprising a sulfide phase of at least one metal from group VIII preferably chosen from nickel and cobalt, taken alone or in a mixture, in association with at least one metal from group VIB preferably chosen from molybdenum and tungsten, taken alone or in a mixture. Preferably, said hydroisomerization catalyst comprises a sulfide phase of nickel and molybdenum, a sulfide phase of nickel, molybdenum and tungsten or a sulfide phase of nickel and tungsten.Preferably, said hydroisomerization catalyst comprises a nickel and tungsten sulfide phase.

[0051] The content of group VIB metal and preferably tungsten and / or molybdenum is advantageously between 5 and 45% by weight in oxide equivalent relative to the finished catalyst, preferably between 10 and 40% by weight and very preferably between 15 and 35% by weight and the content of group VIII metal and preferably nickel and / or cobalt of said catalyst is advantageously between 0.5 and 10% by weight in oxide equivalent relative to the finished catalyst, preferably between 1 and 8% by weight and very preferably between 1.5 and 6% by weight. According to the invention, said catalyst is used in its sulfurized form.

[0052] Said catalyst used in hydroconversion step b) of the process according to the invention may also advantageously contain a doping element chosen from phosphorus and boron, taken alone or in a mixture and preferably phosphorus. Said doping element may be introduced into the matrix or preferably be deposited on the support. Silicon may also be deposited on the support, alone or with phosphorus and / or boron and / or fluorine.

[0053] The weight content of oxide of said doping element is advantageously less than 20% and preferably less than 10% and is advantageously at least 0.001%.

[0054] The metals are advantageously introduced into the catalyst by any method known to those skilled in the art, such as, for example, co-mixing, dry impregnation, excess impregnation or exchange impregnation.

[0055] According to the invention, the hydroisomerization catalyst further comprises, advantageously, a zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one oxide binder.

[0056] Preferably, the zeolite of structural type BEA is zeolite Beta and the zeolite of structural type FAU is zeolite Y. Preferably, the hydroisomerization catalyst comprises a zeolite Beta alone or in admixture with a zeolite Y.

[0057] In a preferred embodiment, the hydroisomerization catalyst comprises a Y zeolite and a Beta zeolite.

[0058] In another preferred embodiment, the hydroisomerization catalyst comprises only a Beta zeolite.

[0059] Said binder is advantageously chosen from silica (SiC^), alumina (AI2O3), clays, titanium oxide (TiC^), boron oxide (B2O3) and zirconia (ZrC^) taken alone or as a mixture. Preferably, said binder is chosen from silica, silica alumina and alumina and even more preferably, said binder is alumina in all its forms known to those skilled in the art, such as for example gamma alumina.

[0060] A preferred hydroisomerization catalyst comprises and preferably consists of a nickel and tungsten sulfide phase and a support comprising and preferably consisting of at least one Y zeolite and one Beta zeolite and at least one alumina binder.

[0061] Preferably, said support comprises from 5 to 50% by weight of zeolites, preferably from 7% to 45% by weight, and very preferably between 10% and 40% by weight, relative to the total weight of said support.

[0062] Step a) of hydrotreatment and step b) of hydroisomerization can advantageously be carried out in a single reactor or in different reactors and preferably in a single reactor.

[0063] In the case where step a) and step b) are carried out in a single reactor, one or more catalytic beds comprising at least one hydrotreatment catalyst may be used. Similarly, one or more catalytic beds comprising at least one hydroisomerization catalyst according to the invention may also be used.

[0064] The proportion of the hydrotreatment catalyst in hydrotreatment step a) advantageously represents between 50 and 90% and preferably between 55 and 85% of the total volume of catalyst. The proportion of the hydroisomerization catalyst in hydroisomerization step b) advantageously represents between 10 and 50% and preferably between 15 and 45% of the total volume of catalyst.

[0065] The total catalyst volume is understood to mean the sum of the volume of hydrotreatment catalyst and the volume of hydroisomerization catalyst contained respectively in steps a) and b), whether steps a) and b) are carried out in a single reactor or in several reactors.

[0066] In accordance with step c) of the process according to the invention, the effluent from step b) undergoes a fractionation step making it possible to recover at least one diesel fraction.

[0067] Preferably, said step c) comprises a gas-liquid separation step followed by a water removal step.

[0068] Said step c) may also advantageously comprise an atmospheric distillation step and possibly a vacuum distillation, to obtain at least one middle distillate fraction.

[0069] The purpose of said step c) is to separate the gases from the liquid, to eliminate the water and in particular, to recover the hydrogen-rich gases which may also contain light gases such as the C1 - C4 cut and at least one diesel cut, possibly at least one kerosene cut and possibly at least one naphtha cut.

[0070] In a preferred embodiment, the process according to the invention does not include a step of steam cracking at least one of the effluents from step c).

[0071] EXAMPLES

[0072] Examples 1 to 5 describe the preparation of catalysts C1 to C5.

[0073] Examples 6 to 9 describe the evaluation in hydrotreatment and hydroisomerization of a feedstock from a renewable source of the catalyst sequences with C1 with one of the catalysts C2 to C5.

[0074] Example 1: Preparation of a hydrotreatment catalyst (C1)

[0075] The catalyst is based on nickel, molybdenum and phosphorus on alumina with molybdenum oxide M0O3 contents of 22% by weight, nickel oxide NiO of 4% by weight and phosphorus oxide P2O5 of 5% by weight relative to the total weight of the finished catalyst supported on gamma alumina. The shaping is carried out through a die equipped with orifices of 1.85 mm in diameter. This catalyst is obtained by dry impregnation of an aqueous solution comprising the metal precursors (molybdenum trioxide and nickel hydroxycarbonate) and orthophosphoric acid. The catalyst then undergoes a calcination step.

[0076] Example 2: Preparation of a hydroconversion catalyst not in accordance with the invention (C2)

[0077] Preparation of a silica-alumina gel SA1

[0078] A boehmite G1 gel is prepared according to Example 1 of US4154812 and spray-dried, and has the following characteristics:

[0079] Table 1: Characteristics of boehmite gel G1 prepared according to patent US4154812

[0080] 126 g of this boehmite gel are dispersed in 1450 g of water acidified with 3.9 g of 68% nitric acid. The suspension obtained is stirred at room temperature using a mechanical stirrer. One liter of a silicic acid sol is prepared by passing through an ion exchange resin (previously acidified) a sodium silicate solution diluted to the concentration necessary to obtain a quantity equivalent to 60 g of SiO2 in the sol. The silica sol obtained is added to the boehmite suspension using a peristaltic pump at a flow rate of 22 mL / min. The mixture is then heated to 60°C and matured at this temperature with stirring for 1 hour. The suspension is then filtered on a sintered Büchner tool to obtain the SA1 silica-alumina gel.

[0081] X-ray fluorescence measurement on SA1 silica-alumina gel indicates a silica content of 32.2% by weight, expressed as % by weight of SiC>2 relative to the total oxide content (SiC>2 + AI2O3). This SA1 gel has a loss on ignition of 70.8%.

[0082] Loss on ignition corresponds to the water content of the material, it is measured by the loss of mass after heat treatment at 1000°C for 4 hours.

[0083] Zeolite Z1

[0084] A USY type Z1 zeolite is used (with a Si / AI ratio of 15 at / at and a lattice parameter of 24.28 A)

[0085] S1 support shaping

[0086] 218 g of silica-alumina gel SA1, 8 g of zeolite Z1 and 11.7 g of boehmite gel G1 are mixed and kneaded at 50 rpm in a Z-arm mixer, then the paste obtained is extruded through a trilobed die with a diameter of 2.5 mm. The quantity of zeolite Z1 added corresponds to a mass content of 10% by weight of Z1 relative to the total weight of the dry support.

[0087] Hydrothermal treatment of the S1 support

[0088] After drying for 20 hours at 80°C in a ventilated oven, the extrudates are hydrothermally treated at 450°C for 2 hours under an air flow containing less than 40 g of water per kilogram of dry air, then at 800°C for 2 hours in the presence of water vapor at 200 g of water per kilogram of dry air.

[0089] Preparation of catalyst C2 (not in accordance with the invention)

[0090] The support extrudates S1 are then subjected to a dry impregnation step with an aqueous solution of ammonium metatungstate and nickel nitrate left to mature in a water maturer for 24 hours at room temperature, dried at 120°C for 5 hours. The weight content of tungsten oxide WO3 of the final dry catalyst is 21%, the nickel oxide NiO content is 3.5%. Example 3: Preparation of a hydroconversion catalyst according to the invention (C3)

[0091] For the preparation of the catalyst support, a mixture of alumina gel and beta zeolite (with a Si / Al ratio of 13 at / at) is formed by kneading-extrusion through a die with 2 mm diameter trilobed orifices, dried at 80°C and then calcined at 550°C. The beta zeolite content in the support is 10% by weight.

[0092] The support extrudates are then subjected to a dry impregnation step with an aqueous solution of molybdenum trioxide, nickel hydroxycarbonate and phosphoric acid left to mature in a water maturer for 24 hours at room temperature and dried at 120°C for 5 hours. The weight content of molybdenum oxide M0O3 of the final dried catalyst is 19%, the nickel oxide NiO content is 3.8% and the phosphorus content P2O5 is 4.3%.

[0093] Example 4: Preparation of a hydroconversion catalyst in accordance with the invention (C4)

[0094] For the preparation of the catalyst support, a mixture of alumina gel and beta zeolites (with a Si / Al ratio of 13 at / at) and USY (with a Si / Al ratio of 15 at / at and a mesh parameter of 24.28 A) is formed by kneading-extrusion, through a die equipped with trilobed orifices of 2 mm diameter, dried at 80°C and then calcined at 550°C. The beta zeolite content in the support is 3% by weight. The USY zeolite content in the support is 10% by weight.

[0095] The support extrudates are then subjected to a dry impregnation step with an aqueous solution of ammonium metatungstate and nickel nitrate left to mature in a water maturer for 24 hours at room temperature, dried at 120°C for 5 hours. The weight content of tungsten oxide WO3 of the final dried catalyst is 28%, the nickel oxide NiO content is 3.6%.

[0096] Example 5: Preparation of a hydroconversion catalyst in accordance with the invention (C5)

[0097] For the preparation of the catalyst support, a mixture of alumina gel and beta zeolites (with a Si / Al ratio of 13 at / at) and USY (with a Si / Al ratio of 15 at / at and a mesh parameter of 24.28 A) is formed by kneading-extrusion, through a die equipped with trilobed orifices of 2 mm diameter, dried at 80°C and then calcined at 550°C. The beta zeolite content in the support is 5% by weight. The USY zeolite content in the support is 5% by weight. The support extrudates are then subjected to a dry impregnation step with an aqueous solution of molybdenum trioxide, nickel hydroxycarbonate and phosphoric acid, left to mature in a water maturer for 24 hours at room temperature and dried at 120°C for 5 hours. The weight content of molybdenum oxide M0O3 in the finished catalyst after drying is 19%, the content of nickel oxide NiO is 3.8% and the content of phosphorus P2O5 is 4.3%.

[0098] Example 6 to 9: Evaluation in Hydrotreatment and hydroconversion of a feedstock from a renewable source according to a process in accordance with the invention of the sequences of catalyst C1 with catalysts C2 to C5

[0099] In a reactor temperature-controlled to ensure isothermal operation and a fixed bed loaded with 60% by volume of hydrotreatment catalyst C1 and 40% by volume of hydroconversion catalyst. Catalyst C1 is placed at the reactor inlet and the hydroconversion catalyst in second position (at the reactor outlet). The catalysts being previously sulfurized, the hydrotreatment and hydroconversion of pre-refined rapeseed oil with a density of 920 kg / m is carried out. 3having an oxygen content of 11% by weight. The fatty acid distribution of rapeseed oil is detailed in Table 2. Prior to the hydrotreatment stage, said feedstock is added with dimethyl disulfide in order to adjust its sulfur content to 50 ppm by weight.

[0100] Table 2

[0101] Acid composition

[0102] (%) fat

[0103] 14:0 0.1

[0104] 16:0 5.0

[0105] 16:1 0.3

[0106] 17:0 0.1

[0107] 17:1 0.1

[0108] 18:0 1 ,5

[0109] 18:1 trans <0.1

[0110] 18:1 cis 60.1

[0111] 18:2 trans <0.1

[0112]

[0113] Table 2: Characteristics of rapeseed oil used as feedstock for hydrotreatment

[0114] Before the hydrotreatment of the feedstock, the catalysts are sulfided in situ in the unit, with isane added with 2% by weight of dimethyl disulfide, under a total pressure of 7 MPa, a hydrogen / diesel ratio added of 1000 Nm 3 by m 3 The volume of sulfurization charge per volume of catalyst per hour is set at 0.41. Sulfurization is carried out for 12 hours at 350°C, with a temperature increase ramp of 10°C per hour.

[0115] After sulfurization, the operating conditions of the unit are adjusted in order to carry out the hydrotreatment and hydroconversion of the feedstock:

[0116] - WH (charge volume / total catalyst volume / hour): 0.41 h -1 ,

[0117] - total working pressure: 7 MPa,

[0118] - hydrogen / charge ratio: 1000 Nm 3 hydrogen / m 3 dump,

[0119] The hydrogen used is supplied by Air Product and has a purity greater than 99.999% by volume.

[0120] Temperature steps at 330 to 360°C are carried out in order to vary the severity of the hydroconversion.

[0121] At the unit outlet, an online analysis by gas chromatography and a gas meter are used to calculate the mass of light hydrocarbons produced and present in the hydrogen stream. The liquid effluent is accumulated for 12 hours. Said liquid effluent is then weighed and analyzed by simulated distillation (ASTM D2887) to determine the yield of middle distillate (120°C cut) + , corresponding to the hydrocarbons present in the gas and liquid fraction whose boiling temperature is more than 120°C).

[0122] The middle distillate yield is calculated as follows:

[0123] Yield (average distillate) = [(liquid effluent mass* % cut 120°C + / 100+ mass [C8- C13]gas) / (liquid effluent mass + light hydrocarbon mass (gas) + water mass + COx mass)] * 100

[0124] The liquid effluent mass corresponds to the mass of the liquid recipe accumulated over 12 hours

[0125] The %cut 120°C+ is obtained by simulated distillation: mass fraction of the liquid effluent whose boiling point is higher than 120°C

[0126] The [C8-C13]gas mass is obtained by on-line gas chromatography analysis of the hydrogen flow leaving the unit. It corresponds to the mass of hydrocarbon compounds with a carbon atom count between 8 and 13.

[0127] The water mass is the sum of the mass of settled water present in the liquid effluent and the mass of water present in the gases and analyzed online by gas chromatography.

[0128] The mass of COx is the mass of carbon oxides (CO and CO2) present in the gas phase, it is determined by online analysis by gas chromatography.

[0129] Furthermore, the cloud point is determined by the ASTM D5773 method.

[0130] According to example 6 (not in accordance with the invention), the first zone is loaded with catalyst C1 (60% of the volume), then the second with catalyst C2 (40% of the volume).

[0131] According to example 7 (in accordance with the invention), the first zone is loaded with catalyst C1 (60% of the volume), then the second with catalyst C3 (40% of the volume).

[0132] According to example 8 (in accordance with the invention), the first zone is loaded with catalyst C1 (60% of the volume), then the second with catalyst C4 (40% of the volume).

[0133] According to Example 9 (in accordance with the invention), the first zone is loaded with catalyst C1 (60% of the volume), then the second with catalyst C5 (40% of the volume). Catalyst C2 is defined as the reference. The performance criteria are as follows:

[0134] - Converting activity expressed by the increase in temperature compared to the reference required to reach a cloud point of -7°C of the liquid effluent. A negative value indicates a gain in activity.

[0135] - Average distillate yields obtained for a liquid effluent cloud point of -7°C. It is expressed as a deviation from the reference. A negative value indicates a loss of yield.

[0136] The main characteristics of the effluents produced and the associated operating conditions are shown in Table 3.

[0137] Table 3

[0138] Table 3: Main characteristics of effluents produced by hydrotreatment and hydroisomerization

[0139] The compliant C3 catalyst allows the production of diesel cuts with a conversion activity gain of 21°C compared to the base case while limiting the drop in middle distillate yield. The compliant C4 catalyst allows the production of diesel cuts with a conversion activity gain of 19°C compared to the base case while allowing a gain in middle distillate yield of +3 compared to the base case.

[0140] The compliant C5 catalyst allows the production of diesel cut with a gain in conversion activity of 14°C compared to the base case while limiting the drop in middle distillate yield.

Claims

CLAIMS 1. Process for treating a feedstock from a renewable source comprising at least the following steps: a) a step of hydrotreating said feedstock in the presence of at least one fixed-bed catalyst, said hydrotreatment catalyst comprising a hydrogenating function and an oxide support, at a temperature of between 200 and 450°C, at a pressure of between 1 MPa and 10 MPa, at an hourly space velocity of between 0.1 h -1 and 10 a.m. -1 and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 70 and 1700 Nm 3 hydrogen / m 3of charge, b) a step of hydroisomerization of the entire hydrocarbon liquid effluent from step a) in the presence of a bifunctional fixed-bed hydroisomerization catalyst, said catalyst comprising a sulfide phase of at least one metal from group VIII in combination with at least one metal from group VIB of the periodic table and a support comprising a zeolite of structural type BEA alone or in a mixture with a zeolite of structural type FAU and at least one binder, said hydroisomerization step being carried out at a temperature of between 250°C and 500°C, at a pressure of between 1 MPa and 10 MPa, at an hourly space velocity of between 0.1 and 10 h -1 and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 70 and 1500 Nm 3 / m 3 of charge, c) a step of fractionation of the effluent from step b) to obtain at least one diesel fraction.

2. Method according to claim 1 in which the feedstock from renewable sources is chosen from oils and fats of vegetable or animal origin, or mixtures of such feedstocks, containing triglycerides and / or free fatty acids and / or esters.

3. Process according to one of claims 1 or 2 wherein in step a), the feed is brought into contact with a fixed-bed catalyst at a temperature of between 220 and 350°C, at a pressure of between 1 MPa and 6 MPa, at an hourly space velocity of between 0.1 h -1 and 10 a.m. 1 The charge is brought into contact with the catalyst in the presence of hydrogen and in the presence of a total quantity of hydrogen mixed with the charge such that the hydrogen / charge ratio is between 150 and 750 Nm 3 hydrogen / m 3 dump.

4. Process according to one of claims 1 to 3 in which the fixed bed hydrotreatment catalyst used in step a) advantageously comprises at least one metal from group VIII and / or group VIB, taken alone or as a mixture and a support chosen from the group formed by alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals.

5. Process according to one of claims 1 to 4 in which the hydroisomerization step b) operates at a temperature of between 250°C and 450°C, and very preferably, between 250 and 400°C, at a pressure of between 2 MPa and 10 MPa and very preferably, between 1 MPa and 9 MPa, at an hourly volumetric flow rate of between 0.2 and 7 h-1 and very preferably, between 0.5 and 5 h-1, at a hydrogen flow rate such that the hydrogen / feed volume ratio is between 100 and 1000 normal m3 of hydrogen per m3 of feed and preferably between 150 and 1000 normal m3 of hydrogen per m3 of feed.

6. Process according to one of claims 1 to 5 in which said hydroisomerization catalyst comprises a sulfide phase of at least one metal from group VIII, preferably chosen from nickel and cobalt, taken alone or as a mixture, in association with at least one metal from group VIB, preferably chosen from molybdenum and tungsten, taken alone or as a mixture.

7. The process of claim 6 wherein said hydroisomerization catalyst comprises a nickel and molybdenum sulfide phase, a nickel, molybdenum and tungsten sulfide phase or a nickel and tungsten sulfide phase and preferably a nickel and tungsten sulfide phase.

8. Process according to one of claims 1 to 7 in which the hydroisomerization catalyst comprises a Beta zeolite alone or in a mixture with a Y zeolite.

9. Process according to claim 8 in which the hydroisomerization catalyst comprises a Y zeolite and a Beta zeolite.

10. Process according to one of claims 1 to 9 in which step a) of hydrotreatment and step b) of hydroisomerization are carried out in a single reactor or in different reactors and preferably in a single reactor.

11. Method according to one of claims 1 to 10 in which the method according to the invention does not comprise an intermediate separation step between step a) and step b).

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