Method for the hydrogenation of olefins contained in a middle-distillate-type olefinic feedstock in the presence of a nickel-copper catalyst

Abstract

The invention relates to a method for the hydrogenation of olefins contained in a middle-distillate-type olefinic feedstock derived at least partly from a renewable source, in the presence of a catalyst comprising nickel and copper, in an amount of between 10% and 50% by weight of nickel, relative to the total weight of the catalyst, and between 0.15% and 1.3% by weight of copper, relative to the total weight of the catalyst, and a support comprising alumina.

Description

[0001] PROCESS FOR HYDROGENATING OLEFINS CONTAINED IN A MIDDLE DISTILLATE OLEFIN FEED IN THE PRESENCE OF A NICKEL-CORP CATALYST

[0002] Scope of the invention

[0003] The present invention relates to a process for the hydrogenation of olefins contained in an olefinic feedstock of the middle distillate type, in particular as a base fuel and / or kerosene, obtained from a hydrocarbon source of renewable origin, and more particularly obtained from the transformation of an alcoholic feedstock using a process comprising a dehydration step of the feedstock and at least one oligomerization step.

[0004] State of the art

[0005] Demand for the use of biomass as at least a partial replacement for petroleum resources in fuel synthesis is growing. Consequently, the use of bioethanol for the synthesis of fuel bases is receiving increasing interest.

[0006] Bioethanol is ethanol of agricultural origin, meaning that it is produced from renewable sources derived from biomass such as living plant matter.

[0007] Most bioethanol is produced today by fermenting the sugars contained in plant-based raw materials. From sugar crops, the first step in the transformation process is to obtain a sugary juice by hot water extraction for sugar beets or by crushing and pressing for sugarcane. After possible concentration, these juices or syrups are introduced into fermenters where the biological transformation of sugars into ethanol takes place, with the co-production of CO2 under the action of microorganisms (yeast). The resulting wines contain approximately 10% alcohol in water. A distillation step allows the azeotropic composition of the ethanol / water binary (8% water) to be achieved. To obtain complete dehydration, the mixture is then passed through a molecular sieve.In cereal plants (maize, wheat), fermentable sugars into ethanol are present in the form of a polymer called starch; to release them, a prior step of enzyme-catalyzed hydrolysis is necessary.

[0008] Technologies enabling the transformation of lignocellulosic biomass (wood, grass, straw, and other agricultural waste, etc.) into bioethanol have also recently become available. These technologies allow the use of resources that do not compete with human or animal food (in the sense of livestock farming).

[0009] There are also technologies that allow ethanol to be obtained from waste gas from steelmaking or household waste incineration, using gasification of this waste followed by microbial fermentation from CO and part of the CO2 from the gas, and nutrient inputs for microorganisms.

[0010] The use of ethanol is primarily intended for gasoline production, not for the production of diesel or kerosene. Another very promising avenue is the use of ethanol as a biofuel in diesel engines. E-Diesel biofuel is a blend consisting of 85% to 95% diesel, anhydrous (water-free) ethanol, and a specially formulated additive package designed to stabilize the blend and mitigate some of bioethanol's drawbacks, such as its low cetane number and poor lubricity.

[0011] Blending conventional diesel with ethanol and an additive improves combustion efficiency and slightly increases fuel volatility. The main result is a reduction in emissions of regulated pollutants such as particulate matter (PM10) and smoke. This reduction is due to the oxygen content of the biofuel, which limits particulate formation during fuel combustion.

[0012] Mixing conventional jet fuel (Jet A1 according to customs specifications) with ethanol is not accepted by equipment manufacturers in the current commercial specification (ASTM D7566), primarily due to issues with flammability (flash point), stability, water absorption, and energy content per liter. These drawbacks suggest that while it may be possible to run light aircraft on ethanol, its use in existing fleets would not be straightforward.

[0013] The transformation of ethanol into hydrocarbons is therefore an interesting way to valorize renewable resources towards fuels.

[0014] The literature is very rich on the transformation of alcohols, for example of the methanol type, into olefins or aromatics to produce a gasoline cut on acid catalysts, often zeolitic.

[0015] The production of ethylene from ethanol is a known process that has been developed on an industrial scale in a few units. For example, ethanol-to-ethylene dehydration units were built in Brazil during the 1970s, following the oil crisis. Ethanol is catalytically converted into ethylene at temperatures above 300°C. The catalysts used can be of various types: activated alumina, silica alumina, etc. Scientific Design developed its own technology for dehydrating ethanol into ethylene and, following the development of a new catalyst, introduced in an industrial unit, published an article ("Ethylene from Ethanol", NK Kochar, R. Merims, and AS Padia, CEP, June 1981). US patents 4,232,179, US 4,396,789, US 4,234,752, US 4,396,789, US 4,698,452 can also be cited.

[0016] Documents FR2959750 and FR2959752 disclose processes for producing middle distillate hydrocarbon bases from an ethanol feedstock, comprising ethanol dehydration steps followed by two oligomerization steps, one in homogeneous phase and the other in heterogeneous phase, and then a fractionation step to obtain a middle distillate base (diesel and / or kerosene). At least a portion, and preferably all, of the middle distillate base undergoes a hydrogenation step of the olefins produced to make them suitable for incorporation into the fuel pool. Preferably, at least a portion, and preferably all, of the middle distillate base is contacted with a hydrogen-rich gas in the presence of a catalyst comprising at least one Group VIII metal, nickel- or palladium-based, and a support selected from alumina, silica, or silica-alumina.The effluent from the hydrogenation stage contains essentially valuable hydrocarbons that can be incorporated into the kerosene and / or diesel pool, preferably into the kerosene pool.

[0017] Objects of the invention

[0018] Continuing its research into improving existing processes, the Applicant has surprisingly discovered that the implementation of a nickel and copper-based catalyst, with a specific copper content, makes it possible to obtain a significant improvement in terms of total hydrogenation activity of olefins contained in an olefinic feed of the middle distillate type, at least partly from a renewable source, and in particular from a C2 renewable alcohol feed.

[0019] The present invention relates to a process for hydrogenating olefins contained in a middle distillate olefin feedstock, at least partly from a renewable source, at a pressure between 0.1 MPa and 10 MPa, at a temperature between 25°C and 200°C, and at a VVH between 0.25 h' 1 and 8 p.m. 1 in the presence of a catalyst comprising nickel and copper, with nickel content at 10% and 50% by weight relative to the total weight of the catalyst, and copper content at 0.15% and 1.3% by weight relative to the total weight of the catalyst, and a support comprising alumina. According to one or more embodiments of the invention, said olefinic feed comprises at least 80% by weight of C5+ olefins relative to the total weight of olefins contained in said olefinic feed.

[0020] According to one or more embodiments of the invention, said olefinic charge comprises at most 50% by weight of C4 to C8 olefinic compounds, and at least 50% by weight of C10+ olefinic compounds relative to the total weight of said olefinic charge.

[0021] According to one or more embodiments of the invention, 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.

[0022] According to one or more embodiments of the invention, said olefinic charge is obtained from alcohol of renewable origin in C2.

[0023] According to one or more embodiments of the invention, said olefinic feedstock is obtained from C2 renewable alcohol obtained at least according to the following steps: i) a dehydration step of C2 renewable alcohol to produce a C2 olefinic feedstock; ii) a first oligomerization step of said C2 olefinic feedstock to obtain at least one olefinic effluent comprising at least 80% by weight of C4+ olefins relative to the total weight of olefins contained in said olefinic effluent; iii) a second oligomerization step of at least part of the olefinic effluent obtained at the end of step ii) to obtain said olefinic feed of the middle distillates type, iv) optionally, a fractionation step of said olefinic feed of the middle distillates type obtained at the end of step iii) to obtain at least one gasoline cut and at least one cut of middle distillates (diesel and / or kerosene).

[0024] According to one or more embodiments of the invention, said catalyst comprises a copper content of between 0.25 and 0.45% in elemental copper relative to the total weight of the catalyst.

[0025] According to one or more embodiments of the invention, said catalyst comprises a nickel content of between 13% and 27% in element nickel relative to the total weight of the catalyst.

[0026] According to one or more embodiments of the invention, the size of the nickel particles in said catalyst is less than 6 nm. According to one or more embodiments of the invention, said catalyst comprises a support having a specific surface area between 10 and 220 m². 2 / g.

[0027] According to one or more embodiments of the invention, said catalyst is obtained by a preparation process comprising at least the following steps: a) the following sub-steps are carried out in sequence: a1) a solution comprising at least one nickel precursor and at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function are brought into contact with the alumina support to obtain a catalyst precursor; a2) the catalyst precursor obtained at the end of step a1) is dried at a temperature below 250°C; a3) the dried catalyst precursor obtained at the end of step a2) is calcined at a temperature between 250°C and 600°C;b) the following sub-steps are carried out in sequence: b1) the alumina support is contacted with at least one solution containing at least one copper precursor and one nickel precursor; b2) the catalyst precursor obtained at the end of step b1 is dried at least once at a temperature below 250°C; b3) the dried catalyst precursor obtained at the end of step b2 is calcined at a temperature between 250°C and 600°C; steps a) and b) being carried out separately in any order.

[0028] According to one or more embodiments of the invention, said catalyst preparation process further comprises a reduction step c) in which the catalyst obtained at the end of the sequence of steps a) and b), or b) and a), is reduced by bringing said catalyst into contact with a reducing gas at a temperature greater than or equal to 250°C and less than or equal to 500°C for a period greater than or equal to 5 minutes and less than 3 hours.

[0029] According to one or more embodiments of the invention, the organic compound of substep a1) is selected from oxalic acid, malonic acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, levulinic acid, ethylene glycol, propane-1,3-diol, butane-1,4-diol, glycerol, xylitol, mannitol, sorbitol, diethylene glycol, triethylene glycol, glucose, gamma-valerolactone, dimethyl carbonate, diethyl carbonate, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylmethanamide, 2-pyrrolidone, γ-lactam, lactamide, urea, alanine, arginine, the lysine, proline, serine, EDTA.

[0030] According to one or more embodiments of the invention, the molar ratio between nickel and copper supplied in substep b1) is between 0.5 and 3 mol / mol.

[0031] Detailed description

[0032] 1. Definitions

[0033] In the following detailed description, many specific details are presented to provide a more thorough understanding of the process. However, it will be apparent to those skilled in the art that the process can be implemented without necessarily including all of these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0034] It is specified that, throughout this description, the expression "between ... and ..." should be understood as including the cited limits, unless otherwise specified.

[0035] In this description, the term "include" is synonymous with (means the same as) "comprise," "include," and "contain," and is inclusive or open-ended, not excluding other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist."

[0036] In addition, when used in this 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 that reference value, which may be a temperature, pressure, distance, speed, flow rate, content of compound(s), etc.

[0037] In the sense of the present invention, the different embodiments presented can be implemented separately or in combination with each other, without limitation of combinations when this is technically feasible.

[0038] In the context of the present invention, different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the context of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0039] In what follows, 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 (or VI II B) according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IIIPAC classification.

[0040] The specific surface area of ​​BET is measured by nitrogen physisorption. The specific surface area of ​​BET is measured by nitrogen physisorption according to ASTM D3663-03 as described in Rouquerol F.; Rouquerol J.; Singh K. "Adsorption by Powders & Porous Solids: Principle, methodology and applications", Academic Press, 1999.

[0041] The total pore volume is measured by mercury porosimetry according to ASTM D4284-92 with a wetting angle of 140°, for example using an Autopore® III model device from Microméritics®.

[0042] The levels of nickel, copper and alkali elements, such as potassium or sodium, are measured by X-ray fluorescence.

[0043] The term "nickel particle size" refers to the diameter of nickel crystallites in their oxide form. The diameter of nickel crystallites in their oxide form is determined by X-ray diffraction, from the width of the diffraction line located at the angle 2θ = 43° (i.e., along the crystallographic direction

[0200] ) using Scherrer's relation. This method, used in X-ray diffraction on powders or polycrystalline samples, relates the full width at half maximum (FWHM) of the diffraction peaks to the particle size and is described in detail in the reference: Appl. Cryst. (1978), 11, 102-113 "Scherrer after sixty years: A survey and some new results in the determination of crystallite size", J.I. Langford and A.J.C. Wilson.

[0044] 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.

[0045] By hydrocarbon Cn cut, we mean a cut comprising hydrocarbons with n carbon atoms.

[0046] A Cn+ cut is understood to be a cut comprising hydrocarbons with at least n carbon atoms.

[0047] By Cn- section we mean a section comprising hydrocarbons with at most n carbon atoms.

[0048] The hourly volumetric velocity "WH" refers to the volumetric flow rate of the feed at the reactor inlet in m³ 3 / h at 15°C, 0.1 MPa divided by the catalyst volume in m³ 3contained in the reactor. By hourly volumetric velocity “PPH”, we mean the mass flow rate of the feed at the reactor inlet in kg / h at 15°C, 0.1MPa divided by the mass of catalyst in kg contained in the reactor.

[0049] In this description, pressures are expressed as relative values ​​unless otherwise specified.

[0050] 2. Hydrogenation of olefins in a middle distillate-type olefinic feedstock

[0051] According to the invention, the hydrogenation process for olefins contained in a middle distillate olefin feedstock, at least partly from a renewable source, is carried out at a pressure between 0.1 MPa and 10 MPa, at a temperature between 25°C and 200°C, and at a VVH between 0.25 h⁻¹ and 20 h⁻¹. -1in the presence of a catalyst comprising nickel and copper, at a rate of 10% and 50% by weight of nickel element relative to the total weight of the catalyst, and at a rate of 0.15% and 1.3% by weight of copper element relative to the total weight of the catalyst, and a support and a support comprising alumina.

[0052] The said middle distillate olefinic feed advantageously comprises at least 80% by weight of olefins comprising more than 4 carbon atoms (or C5+) relative to the total weight of olefins contained in said feed, preferably at least 90% by weight, and comprises less than 20% by weight, preferably less than 10% by weight of C4 olefins.

[0053] Said middle distillate olefinic feed advantageously comprising at most 50% by weight, and preferably at most 40% by weight, of C4-C8 olefinic compounds, and at least 50% by weight and preferably at least 60% by weight of C10+ olefinic compounds (i.e. comprising 10 or more carbon atoms), the weight percentages being expressed in relation to the total weight of olefins contained in said feed.

[0054] Advantageously, said middle distillate olefinic feedstock is at least partly obtained from a renewable hydrocarbon source, including hydrocarbon sources produced from carbon dioxide recycling.

[0055] Advantageously, the said middle distillate olefinic feedstock is entirely bio-based, that is to say entirely obtained from a renewable hydrocarbon source, in order to produce valuable products of entirely bio-based origin.

[0056] The said middle distillate olefinic feed can be obtained from C2 renewable alcohol, or biomass, or a Fischer-Tropsch unit or a mixture of several renewable sources.Preferably, said middle distillate olefinic feedstock is obtained at least by the following steps: i) a dehydration step of C2 renewable alcohol to produce a C2 olefinic feedstock; ii) a first oligomerization step of said C2 olefinic feedstock to obtain at least an olefinic effluent comprising at least 80% by weight of C4+ olefins relative to the total weight of olefins contained in said olefinic effluent; iii) a second oligomerization step of at least part of the olefinic effluent obtained at the end of step ii) to obtain said olefinic feed of the middle distillate type, iv) optionally, a fractionation step of the middle distillate type feed obtained at the end of step iii) to obtain at least one gasoline cut comprising olefins and at least one middle distillate cut comprising olefins (diesel and / or kerosene).

[0057] When step iv) is carried out, then the olefin hydrogenation process according to the invention is carried out on the cut of middle distillates comprising olefins (diesel and / or kerosene).

[0058] Steps i) to iv) are described in detail below.

[0059] Step i) can be implemented in the presence of an amorphous acid catalyst or a zeolitic acid catalyst, as known to those skilled in the art.

[0060] If the catalyst used in the dehydration is a zeolite catalyst, it shall comprise at least one zeolite selected from among those having at least pore openings containing 10 or 12 oxygen atoms (10MR or 12MR). Preferably, said zeolite catalyst shall comprise at least one zeolite exhibiting a structural type selected from among the structural types MFI, FAU, MOR, FER, and BEA. The zeolite may advantageously be modified by desalumination or desilication using any desalumination 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 between 0.1 h'.1 and 50 hours 1 and preferably between 0.5 h' 1 and 3 p.m. 1 Step ii) 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.

[0061] In a first embodiment, the first oligomerization step 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 mixture and preferably said support is alumina or silica alumina to obtain a C4-rich olefinic hydrocarbon effluent, as described for example in patent FR2959750B1.

[0062] Advantageously, the first oligomerization step operates advantageously 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 a.m. -1 and preferably between 0.4 h -1 and 5 a.m. -1 .

[0063] In a second embodiment, the catalyst used in the first oligomerization step is a homogeneous catalyst, meaning that the catalyst is soluble in the liquid phase composed of dissolved ethylene and its oligomerization products, as, for example, in the process described in French patent FR2959752, which allows the production of hydrocarbon base kerosene from a renewable ethanol feedstock. Since this is a homogeneous catalysis implementation, those skilled in the art may find it helpful to refer to the teachings in US patents US7235703 and US4362650. The homogeneous catalyst advantageously comprises at least one divalent nickel compound, optionally at least one aluminum hydroxycarbyl halide, and optionally at least one Brønsted organic acid. Preferably, the catalyst may also contain at least one carboxylic acid anhydride. The catalyst is in liquid form.

[0064] Advantageously, the operating conditions in the reactor(s) carrying out the first step of oligomerization 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 total absolute pressure in the reactor(s) is between 2 MPa and 8 MPa.

[0065] Typically, the olefinic hydrocarbon effluent from the first oligomerization step 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 percentages by weight being expressed relative to the total mass of olefins contained in said olefinic effluent produced.

[0066] An example of a first step in oligomerization is the DimEne-B® process marketed by the company Axens.

[0067] Another example of a first oligomerization step is the Dimersol-E® process marketed by the company Axens.

[0068] Step iii)

[0069] Step iii) can be carried out by any method known to a person skilled in the art.

[0070] Preferably, at least part of the olefinic effluent obtained at the end of step iii) undergoes a second oligomerization step in the presence of an amorphous or zeolitic heterogeneous catalyst.

[0071] According to a preferred embodiment, the catalyst used in the second oligomerization step iii) is an amorphous heterogeneous catalyst comprising, and preferably made of, an amorphous mineral material selected from silica-aluminas and silicified aluminas.

[0072] According to another preferred embodiment, the second oligomerization step iii) is carried out in the presence of a heterogeneous zeolite catalyst, i.e. a heterogeneous catalyst comprising at least one zeolite, preferably having at least pore openings containing 10 or 12 oxygen atoms (10MR or 12MR), and advantageously chosen from aluminosilicate type zeolites having an overall Si / Al molar ratio greater than 10.

[0073] In one embodiment, said catalyst used in the second oligomerization step iii) comprises at least one zeolite selected from structural type zeolites MFI, MTW, MOR, TON, MEL, MFS, MTT, taken alone or in mixture.

[0074] In one embodiment, said catalyst used in the second oligomerization step iii) comprises at least one zeolite selected from the ZSM-5 zeolites,

[0075] ZSM-12, NU-86, Mordenite, ZSM-22, NU-10, ZBM-30, ZSM-48, ZSM-11, ZSM-57, IZM-2, ITQ-6 and IM-5, taken alone or in mixture, preferably from the zeolites ZSM-5, NU-10 and ZBM-30, taken alone or in mixture, most preferably the zeolite is ZBM-30 and even more preferably the zeolite is ZBM-30 synthesized in the presence of the structuring tri-ethyline etetramine.

[0076] The zeolite used in the catalyst in step iii) can advantageously undergo several post-treatments known to those skilled in the art, such as being modified by desalumination or desilication according to any desalumination method, external surface passivation or desilication known to those skilled in the art, in order to improve its activity and / or stability.

[0077] The catalyst used in the second oligomerization step iii) also advantageously comprises at least one oxide-type matrix, also called a binder. The term "matrix" according to the invention refers to an amorphous or poorly crystallized matrix.

[0078] The matrix is ​​advantageously chosen from among the elements of the group formed by clays (such as, for example, natural clays like kaolin or bentonite), magnesia, aluminas, silicas, silica-aluminas, aluminates, titanium oxide, boron oxide, zirconia, aluminum phosphates, titanium phosphates, zirconium phosphates, and coal. Preferably, the matrix is ​​chosen from among the elements of the group formed by aluminas, clays, and silicas; more preferably, the matrix is ​​chosen from among aluminas; and even more preferably, the matrix is ​​gamma alumina.

[0079] The catalyst used in the second oligomerization step (iii) is advantageously shaped into grains (or particles) of various shapes and sizes. These are advantageously used in the form of cylindrical or multilobed extrudates such as bilobed, trilobed, or multilobed, with straight or twisted shapes, but can also be manufactured and used in the form of crushed powder, tablets, rings, balls, wheels, or spheres. Preferably, these catalysts are in the form of extrudates with a size between 1 and 10 mm.

[0080] The second step iii) of oligomerization is advantageously implemented in at least one fixed-bed reactor.

[0081] The second oligomerization step iii) of the process advantageously operates at a temperature between 50 and 400°C, preferably between 100 and 350°C and preferably between 100 and 300°C, at an absolute pressure between 2 and 15 MPa, preferably between 2 and 8 MPa and preferably between 3 and 8 MPa and at an hourly weight rate between 0.1 and 10 h-1 and preferably between 0.4 and 5h-1.

[0082] The hourly weight rate is defined here as the ratio of the mass flow rate of the "fresh" feed entering step iii) to the mass of catalyst, excluding any recycles. The middle distillate-type olefinic feed produced by the second oligomerization step iii) is an olefinic effluent comprising at least 80% by weight and preferably at least 90% by weight of olefins with more than 4 carbon atoms, and less than 20%, preferably less than 10%, of unreacted C4 olefins (C4 meaning containing 4 carbon atoms), the weight percentages being expressed relative to the total weight of olefins contained in the middle distillate-type effluent produced.

[0083] The middle distillate effluent advantageously comprises at most 50% by weight and preferably at most 40% by weight of C4-C8 olefinic compounds, and at least 50% by weight and preferably at least 60% by weight of C10+ olefinic compounds (i.e. comprising 10 or more carbon atoms), the weight percentages being expressed in relation to the total mass of olefins present in said effluent.

[0084] The process is a flexible process in that the operating conditions and the choice of catalyst in the second step iii) of oligomerization allow the reaction to be directed towards one or the other of the target products, namely in one case towards the major production of a hydrocarbon base of the diesel type and in the other of a hydrocarbon base of the kerosene type.

[0085] In cases where the primary objective is the production of a basic hydrocarbon fuel of the diesel type, the second oligomerization step iii) operates advantageously in the presence of a catalyst comprising at least one zeolite selected from aluminosilicate zeolites having an overall Si / Al ratio greater than 10 and a pore structure of 10 or 12MR, at a temperature between 200 and 300°C, at a pressure between 3 and 7 MPa, and at a weight-per-hour rate between 0.1 and 5 h -1 .

[0086] In cases where the main production of kerosene-type hydrocarbon base is particularly desired, the second step iii) of oligomerization advantageously operates in the presence of an amorphous catalyst, preferably comprising and preferably composed of silica alumina, at a temperature between 100 and 300°C, at a pressure between 2 and 6 MPa and at an hourly weight rate between 0.1 and 5 h' 1 .

[0087] An example of a second oligomerization step iii) is the Polynaphta® process marketed by the company Axens.

[0088] The process may include a step (iv) of fractionating the middle distillate olefinic feed from step (iii). The fractionation step (iv) is advantageously carried out in at least one distillation column so as to separate said middle distillate effluent into at least two cuts:

[0089] - a gasoline blend containing olefins; and

[0090] - a middle distillate cut (diesel and / or kerosene) containing olefins. If step iv) is carried out, then the hydrogenation process according to the invention is carried out on the middle distillate cut containing olefins.

[0091] A light effluent containing C2-C4 compounds can also be separated for valorization either pure or in mixture.

[0092] A heavy fraction having an initial boiling point between 350°C and 370°C can also be advantageously separated.

[0093] The term "gasoline" cut refers to the cut comprising hydrocarbon compounds whose boiling point is between ambient temperature and 220°C.

[0094] The term "middle distillates" refers to the cut comprising hydrocarbon compounds with a boiling point between 140°C and 360°C.

[0095] At least a portion of the gasoline fraction from the fractionation step iv) can advantageously be recycled in the second oligomerization step iii) of the process as described above. The olefin hydrogenation step according to the invention is carried out following step iii) on the middle distillate olefin feedstock or following step iv) on the middle distillate fraction containing olefins (diesel fuel and / or kerosene). Preferably, the hydrogenation step according to the invention is carried out following step iv) on the middle distillate fraction containing olefins (diesel fuel and / or kerosene).

[0096] 3. Catalyst

[0097] The catalyst used in the process according to the invention comprises, preferably, nickel and copper, in amounts of 10% and 50% by weight of nickel relative to the total weight of the catalyst, and in amounts of 0.15% and 1.3% by weight of copper relative to the total weight of the catalyst, and a support comprising at least one refractory oxide selected from silica, alumina and silica alumina.

[0098] The nickel content in said catalyst according to the invention is advantageously between 10% and 50% by weight in nickel element relative to the total weight of the catalyst, more preferably between 11% and 30% by weight and even more preferably between 12% and 28% by weight, and even more preferably between 13% and 27% by weight relative to the total weight of the catalyst.

[0099] The size of nickel particles, measured in oxide form, in the catalyst is advantageously less than 6 nm, preferably less than 5 nm, more preferably less than 4 nm, and even more preferably less than 3 nm.

[0100] The copper content is advantageously between 0.15% and 1.3% by weight as elemental copper relative to the total weight of the catalyst, preferably between 0.20% and 1.25% by weight, preferably between 0.22% and 0.75% by weight, and even more preferably between 0.25% and 0.45% by weight.

[0101] The specific surface area of ​​the catalyst is generally between 10 m 2 / g and 220 m 2 / g, preferably between 25 m 2 / g and 180 m 2 / g, preferably between 40 m 2 / g and 160 m 2 / g.

[0102] The total porous volume of the catalyst is generally between 0.1 and 1 ml / g, preferably between 0.2 ml / g and 0.8 ml / g, and particularly preferably between 0.3 ml / g and 0.7 ml / g.

[0103] The catalyst (and the support used for its preparation) is in the form of grains advantageously having a diameter between 0.5 mm and 10 mm. The grains may have any shape known to those skilled in the art, for example, spheres (preferably having a diameter between 1 mm and 8 mm), extrudates, tablets, or hollow cylinders. Preferably, the catalyst (and the support used for its preparation) is in the form of extrudates with a diameter between 0.5 mm and 10 mm, preferably between 0.8 mm and 3.2 mm, and most preferably between 1.0 mm and 2.5 mm, and a length between 0.5 mm and 20 mm. The "diameter" of the extrudates is understood to mean the diameter of the circle circumscribed about the cross-section of these extrudates. The catalyst may advantageously be in the form of cylindrical, multilobed, trilobed, or quadrilobed extrudates. Preferably, its shape will be trilobed or quadrilobed.The shape of the lobes can be adjusted according to all methods known from the prior art.

[0104] 4. Support

[0105] The support comprises alumina. Preferably, the support is made of alumina. Alumina generally has a delta, gamma, or theta alumina crystallographic structure, either alone or in mixtures. The characteristics of the alumina mentioned in this section correspond to the characteristics of the alumina before the support is contacted with the precursors of the catalyst's active phase, namely nickel and copper.

[0106] In one embodiment according to the invention, the support is alumina, that is to say, the support comprises at least 95%, preferably at least 98%, and particularly preferably at least 99% by weight of alumina relative to the weight of the support. The alumina generally has a crystallographic structure of the delta, gamma, or theta type, alone or in mixtures.

[0107] In one embodiment according to the invention, the alumina support may include impurities such as metal oxides of groups HA, I II B, IVB, II B, II IA, IVA according to the CAS classification, preferably silica, titanium dioxide, zirconium dioxide, zinc oxide, magnesium oxide and calcium oxide, or alkali metals, preferably lithium, sodium or potassium, and / or alkaline earth metals, preferably magnesium, calcium, strontium or barium, or sulfur.

[0108] The specific surface area of ​​alumina is generally between 10 m 2 / g and 220 m 2 / g, preferably between 25 m 2 / g and 180 m 2 / g, preferably between 40 m 2 / g and 160 m 2 / g.

[0109] The pore volume of alumina is generally between 0.1 ml / g and 1 ml / g, preferably between 0.2 ml / g and 0.8 ml / g, and most preferably between 0.3 ml / g and 0.7 ml / g.

[0110] 5. Process for preparing the catalyst

[0111] An object according to the invention relates to a process for preparing the catalyst comprising at least the following steps: a) the following sub-steps are carried out in sequence: a1) the alumina support is contacted with a solution comprising at least one nickel precursor and at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function to obtain a catalyst precursor; a2) the catalyst precursor obtained at the end of step a1) is dried at a temperature below 250°C; a3) the dried catalyst precursor obtained at the end of step a2) is calcined at a temperature between 250°C and 600°C; b) the following sub-steps are carried out in sequence: b1) the alumina support is contacted with at least one solution containing at least one copper precursor and one nickel precursor;b2) at least one drying step of the catalyst precursor obtained at the end of step b1) is carried out at a temperature below 250°C; b3) the dried catalyst precursor obtained at the end of step b2) is calcined at a temperature between 250°C and 600°C; steps a) and b) being carried out separately in any order.

[0112] Steps a) and b) are described in detail below. Other optional steps are also described in the following section.

[0113] Sub-step a1)

[0114] The contacting of said support with at least one solution comprising at least one nickel precursor and at least one organic compound, as implemented in substep a1), can be carried out by impregnation, either dry or in excess, or by deposition-precipitation, according to methods well known to those skilled in the art. Indeed, it has been observed that catalysts according to the invention prepared in the presence of an organic compound (listed below) are more active than catalysts prepared in the absence of this type of organic compound. This effect is linked to the reduction in the size of the nickel particles.

[0115] Substep a1) is preferably carried out by impregnating the support, for example by contacting said support with at least one aqueous or organic solution (for example, methanol, ethanol, phenol, acetone, toluene, or dimethyl sulfoxide (DMSO)), or alternatively, a mixture of water and at least one organic solvent, containing at least one nickel precursor at least partially dissolved and at least one organic compound comprising at least one carboxylic acid, alcohol, ester, amide, or amine functional group. Preferably, the solution is aqueous. The pH of this solution may be modified by the optional addition of an acid or a base.

[0116] Preferably, said substep a1) is carried out by dry impregnation, which consists of bringing the catalyst support into contact with a solution, containing at least one nickel precursor and at least one organic compound, the volume of which is between 0.25 and 1.5 times the porous volume of the support to be impregnated.

[0117] When the nickel precursor is introduced in aqueous solution, advantageously a nickel precursor is used in the form of nitrate, carbonate, acetate, chloride, hydroxide, hydroxycarbonate, oxalate, sulfate, formate, complexes formed by a polyacid or an acid-alcohol and its salts, complexes formed with acetylacetonates, tetrammine or hexammine complexes, or any other inorganic derivative soluble in aqueous solution, which is brought into contact with said support.

[0118] Preferably, nickel nitrate, nickel hydroxide, nickel carbonate, nickel chloride, or nickel hydroxycarbonate are advantageously used as nickel precursors. Most preferably, the nickel precursor is nickel nitrate, nickel carbonate, or nickel hydroxide.

[0119] The quantities of nickel precursor(s) introduced into the solution are chosen in such a way that the total nickel content in the final catalyst (i.e. after the sequence of steps a) and b), or b) and a)) is between 10 and 50 wt%, preferably between 11 and 30 wt%, preferably between 12 and 27 wt% of said element relative to the total weight of the catalyst, and even more preferably between 13 and 25 wt%.

[0120] Said organic compound is preferably chosen from oxalic acid, malonic acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, levulinic acid, ethylene glycol, propane-1,3-diol, butane-1,4-diol, glycerol, xylitol, mannitol, sorbitol, diethylene glycol, triethylene glycol, glucose, gamma valerolactone, dimethyl carbonate, diethyl carbonate, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylmethanamide, 2-pyrrolidone, y-lactam, lactamide, urea, alanine, arginine, lysine, proline, serine, EDTA.

[0121] Advantageously, the molar ratio between said organic compound and the element nickel also introduced in the step is between 0.01 and 5.0 mol / mol, preferably between 0.05 and 2.0 mol / mol, more preferably between 0.1 and 1.5 mol / mol and even more preferably between 0.2 and 1.2 mol / mol.

[0122] Sub-step a2)

[0123] Substep a2) of drying is advantageously carried out at a temperature below 250°C, preferably between 15°C and 180°C, more preferably between 30°C and 160°C, even more preferably between 50°C and 150°C, and even more preferably between 70°C and 140°C, for a period typically between 0.5 hours and 12 hours, and even more preferably between 0.5 hours and 5 hours. Longer periods are not excluded, but do not necessarily provide any improvement. The drying step can be carried out by any technique known to those skilled in the art. It is advantageously carried out under an inert atmosphere or under an atmosphere containing oxygen or under a mixture of inert gases and oxygen. It is advantageously carried out at atmospheric pressure or at reduced pressure. Preferably, this step is carried out at atmospheric pressure and in the presence of air or nitrogen.

[0124] At the end of substep a2), the total, partial, or absence of the organic compound in the catalyst does not affect the activity and / or selectivity of the catalyst in the context of the hydrogenation of polyunsaturated compounds contained in reformates or in the hydrogenation of olefins in a middle distillate cut.

[0125] Sub-step a3)

[0126] Substep a3) of calcination can be carried out at a temperature between 250°C and 600°C, preferably between 350°C and 550°C, for a typical duration of 0.5 hours to 24 hours, preferably 0.5 hours to 12 hours, and even more preferably 0.5 hours to 10 hours, preferably under an inert atmosphere or an atmosphere containing oxygen. Longer durations are not excluded, but do not necessarily provide any improvement.

[0127] At the end of substep a3), the total, partial, or absence of organic compound in the catalyst does not affect the activity and / or selectivity of the catalyst in the context of the hydrogenation of polyunsaturated compounds contained in reformates or in the hydrogenation of olefins in a middle distillate cut.

[0128] Substep b1)

[0129] The contacting of said support with at least one solution comprising at least one nickel precursor and at least one copper precursor in accordance with the implementation of substep b1), may be carried out by impregnation, dry or in excess, or by deposition-precipitation, according to methods well known to those skilled in the art.

[0130] Substep b1) is preferably carried out by impregnating the catalyst precursor, for example by contacting the support with at least one aqueous or organic solution (e.g., methanol, ethanol, phenol, acetone, toluene, or dimethyl sulfoxide (DMSO)), or alternatively, a mixture of water and at least one organic solvent, comprising, preferably, at least one nickel precursor and at least one copper precursor, at least partially dissolved. Preferably, the solution is aqueous. The pH of this solution may be modified by the optional addition of an acid or a base.

[0131] Preferably, said substep b1) is carried out by dry impregnation, which consists of bringing the support of the catalyst precursor into contact with a solution, comprising, preferably made up of, at least one nickel precursor and at least one copper precursor, the volume of the solution of which is between 0.25 and 1.5 times the porous volume of the support to be impregnated.

[0132] When the nickel precursor is introduced into aqueous solution, advantageously a nickel precursor is used in the form of nitrate, carbonate, acetate, chloride, hydroxide, hydroxycarbonate, oxalate, sulfate, formate, complexes formed by a polyacid or an acid-alcohol and its salts, complexes formed with acetylacetonates, tetrammine or hexammine complexes, or any other inorganic derivative soluble in aqueous solution, which is brought into contact with said catalyst precursor. Preferably, nickel nitrate, nickel hydroxide, nickel carbonate, nickel chloride, or nickel hydroxycarbonate are advantageously used as nickel precursors. Most preferably, the nickel precursor is nickel nitrate, nickel carbonate, or nickel hydroxide.

[0133] When a copper precursor is introduced into aqueous solution, a copper precursor in mineral or organic form is advantageously used. In mineral form, the copper precursor can be chosen from copper acetate, copper acetylacetonate, copper nitrate, copper sulfate, copper chloride, copper bromide, copper iodide, or copper fluoride. Copper nitrate is the preferred precursor salt.

[0134] Advantageously, the molar ratio between nickel and copper supplied at substep b1) is between 0.5 and 3 mol / mol, preferably between 0.7 and 2 mol / mol, more preferably between 0.8 and 1.5 mol / mol, and even more preferably between 0.9 and 1.1 mol / mol.

[0135] The quantities of nickel precursor(s) introduced into the solution are chosen in such a way that the total nickel content in the final catalyst (i.e. after the sequence of steps a) and b), or b) and a)) is between 10% and 50% by weight of nickel element relative to the total weight of the catalyst, more preferably between 11% and 30% by weight and even more preferably between 12% and 28% by weight, and even more preferably between 13% and 27% by weight relative to the total weight of the catalyst.Preferably, in substep b1), the quantities of nickel precursor(s) introduced into the solution supplied in substep b1) are chosen in such a way that they allow the final catalyst to have a nickel content of between 0.05% and 1% by weight in nickel element relative to the total weight of the catalyst, more preferably between 0.07% and 0.75% by weight and even more preferably between 0.09% and 0.6% by weight, and even more preferably between 0.1% and 0.5% by weight.

[0136] The quantities of the copper precursor(s) introduced into the solution according to sub-step b1) are chosen so that the total copper content in the final catalyst (i.e. after the sequence of steps a) and b), or b) and a)) is between 0.15% and 1.3% by weight as elemental copper relative to the total weight of the catalyst, preferably between 0.20% and 1.25% by weight, preferably between 0.22% and 0.75% by weight, and even more preferably between 0.25% and 0.45% by weight.

[0137] Under

[0138] Substep b2) of drying is advantageously carried out at a temperature below 250°C, preferably between 15°C and 180°C, more preferably between 30°C and 160°C, even more preferably between 50°C and 150°C, and even more preferably between 70°C and 140°C, for a typical duration of between 0.5 hours and 12 hours, and even more preferably for a duration of between 0.5 hours and 5 hours. Longer durations are not excluded, but do not necessarily provide any improvement.

[0139] The drying stage can be carried out by any technique known to those skilled in the art. It is advantageously carried out under an inert atmosphere, an atmosphere containing oxygen, or a mixture of inert gases and oxygen. It is advantageously carried out at atmospheric pressure or reduced pressure. Preferably, this stage is carried out at atmospheric pressure and in the presence of air or nitrogen.

[0140] Under

[0141] Substep b3) of calcination can be carried out at a temperature between 250°C and 600°C, preferably between 350°C and 550°C, for a typical duration of 0.5 hours to 24 hours, preferably 0.5 hours to 12 hours, and even more preferably 0.5 hours to 10 hours, preferably under an inert atmosphere or an atmosphere containing oxygen. Longer durations are not excluded, but do not necessarily provide any improvement.

[0142] Implementation of steps a) and b) According to the invention, steps a) and b) and steps a) and c) are carried out separately in any order.

[0143] In a preferred embodiment, step a) is carried out before step b).

[0144] In an embodiment according to the invention, step a) is carried out twice successively, before or after the implementation of step b), preferably before step b). The sequence order of the steps is as follows: a), a), b) or b), a), a). Preferably, the sequence order is as follows: a), a), b). e

[0145] Prior to the use of the catalyst, advantageously at least one reduction treatment step c) is carried out in the presence of a reducing gas after the sequence of steps a) and b), or b) and a), so as to obtain a catalyst comprising nickel at least partially in metallic form.

[0146] This treatment activates the catalyst and forms metallic particles, particularly zero-valent nickel. This reduction treatment can be carried out in-situ or ex-situ, that is, after or before loading the catalyst into the hydrogenation reactor.

[0147] The reducing gas is preferably hydrogen. Hydrogen can be used pure or in a mixture (for example, a hydrogen / nitrogen, hydrogen / argon, or hydrogen / methane mixture). When hydrogen is used in a mixture, any proportion is possible.

[0148] The said reducing treatment is carried out at a temperature greater than or equal to 250°C and less than or equal to 500°C, preferably between 300°C and 500°C, and even more preferably between 350°C and 475°C.

[0149] The duration of the reduction treatment is generally between 5 minutes and 4 hours, preferably between 30 minutes and 2 hours, and even more preferably between 1 and 2 hours. The temperature increase to the desired reduction temperature is generally slow, for example, set between 0.1 and 20°C / min, preferably between 0.5 and 10°C / min.

[0150] The flow rate of pure hydrogen, expressed in L / hour / gram of catalyst, is between 0.01 and 100 L / hour / gram of catalyst, preferably between 0.05 and 10 L / hour / gram of catalyst, and even more preferably between 0.1 and 5 L / hour / gram of catalyst. The invention is illustrated by the following examples.

[0151] Examples

[0152] For all the catalysts mentioned in the examples below, the support is alumina A in the form of extrudates having a specific surface area of ​​80 m². 2 / g, a pore volume of 0.7 mL / g and a median pore diameter of 12 nm. of an aqueous solution of

[0153] The aqueous solution S1 used for the preparation of catalysts A to F is prepared by dissolving 58 g of nickel nitrate (NiNCh, supplier Strem Chemicals®) and 14.35 g of malonic acid (CAS 141-82-2; supplier Fluka®) in 42 mL of distilled water. The solution is heated to 60°C to facilitate the dissolution of the nickel nitrate and is impregnated very quickly to prevent nickel precipitation. The molar ratio of additive to Ni is set at 0.4. This yields solution S1.

[0154] Example 2: Preparation of an aqueous solution of Ni-Cu precursors

[0155] The aqueous solution of NiCu precursors (solution S2) used for preparing NiCu-containing catalysts is prepared by dissolving 14.5 g of nickel nitrate (NiNO₃, supplied by Strem Chemicals®) in 13 mL of distilled water. This yields a solution with a Ni concentration of 116.6 g per liter. The copper nitrate precursor is then added to achieve a Ni / Cu molar ratio of 1. This produces solution S2.

[0156] The solution S1 prepared in Example 1 is dry-impregnated onto 10 g of alumina A. The resulting solid is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. The solution S1 is impregnated a second time onto this solid, which is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. The resulting catalyst A contains 25% by weight of nickel relative to the total weight of the catalyst supported on alumina.

[0157] Example 4: Catalyst B - 25% by weight of Ni + Ni-Cu precursors with 0.3% by weight of Cu, and 0.32% by weight of Ni (Ni / Cu ratio = 1)

[0158] Solution S1 is dry-impregnated onto 10 g of alumina A. The resulting solid is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Solution S1 is impregnated a second time onto this solid, which is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. The two impregnation steps are carried out in such a way as to obtain 25% by weight of nickel relative to the total weight of the final catalyst. This yields the catalyst precursor B1.

[0159] Solution S2 is impregnated onto catalyst precursor B1 to obtain a final Ni / Cu ratio of 1 and 0.3 wt% Cu. The Ni content added at this stage is 0.32 wt% relative to the weight of the final catalyst. The Cu content is 0.3 wt% relative to the weight of the final catalyst. The resulting solid is then oven-dried overnight at 120°C and subsequently calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. This yields catalyst B.

[0160] 5: Catalyst C - 25% by weight of Ni + Ni-Cu with 0.5% by weight of Cu and 0.46% (compliant)

[0161] Solution S1 is dry-impregnated onto 10 g of alumina A. The resulting solid is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Solution S1 is impregnated a second time onto this solid, which is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Both impregnation steps are carried out in such a way as to obtain 25% by weight of nickel relative to the total weight of the final catalyst.

[0162] The catalyst precursor C1 is obtained. Solution S2 is impregnated onto the catalyst precursor C1 so as to obtain in the end a Ni / Cu ratio of 1 and 0.5% by weight of Cu.

[0163] The Ni content added at this stage is 0.46% by weight relative to the weight of the final catalyst. The Cu content is 0.5% by weight relative to the weight of the final catalyst. The resulting solid is then oven-dried overnight at 120°C and subsequently calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. This yields catalyst C.

[0164] Example 6: Catalyst D - 25% by weight of Ni + Ni-Cu with 0.1% by weight of Cu and 0.1% by weight of Ni (Ni / Cu ratio=1) in post-impregnation (non-compliant)

[0165] Solution S1 is dry-impregnated onto 10 g of alumina A. The resulting solid is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Solution S1 is impregnated a second time onto this solid, which is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Both impregnation steps are carried out in such a way as to obtain 25% by weight of nickel relative to the total weight of the final catalyst.

[0166] The catalyst precursor D1 is obtained. The solution S2 is impregnated onto the catalyst precursor D1 so as to obtain in the end a Ni / Cu ratio of 1 and 0.1% by weight of Cu.

[0167] The Ni content added at this stage is 0.1% by weight relative to the weight of the final catalyst. The Cu content is also 0.1% by weight relative to the weight of the final catalyst. The resulting solid is then oven-dried overnight at 120°C and subsequently calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. This yields catalyst D.

[0168] 7: Catalyst E - 25% by weight of Ni + Ni-Cu with 1.5% by weight of Cu and 1.38% (non-compliant)

[0169] Solution S1 is dry-impregnated onto 10 g of alumina A to obtain 25% by weight of nickel alone relative to the total weight of the final catalyst. The resulting solid is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Solution S1 is impregnated a second time onto this solid, which is then oven-dried overnight at 120°C and calcined under an airflow of 1 L / h / g of catalyst at 450°C for 2 hours. Both impregnation steps are carried out in such a way as to obtain 25% by weight of nickel relative to the total weight of the final catalyst.

[0170] The catalyst precursor E1 is obtained. Solution S2 is impregnated onto the catalyst precursor E1 so as to obtain in the end a Ni / Cu ratio of 1 and 1.5% by weight of Cu.

[0171] The Ni content added at this stage is 1.38% by weight relative to the weight of the final catalyst. The Cu content is 1.5% by weight relative to the weight of the final catalyst. The resulting solid is then oven-dried overnight at 120°C and subsequently calcined under an air flow of 1 L / h / g of catalyst at 450°C for 2 hours. This yields catalyst E.

[0172] 8: Characterization

[0173] All catalysts contain the targeted levels during impregnation, i.e. 25% of nickel (characterized by X-ray fluorescence) relative to the total weight of the catalyst, and the % of copper added (characterized by X-ray fluorescence).

[0174] The amount of nickel in metallic form obtained after the reduction step was determined by X-ray diffraction (XRD) analysis of catalyst samples in powder form. Between the reduction step and throughout the XRD characterization process, the catalysts were never exposed to air. Diffraction patterns were obtained by X-ray crystallography using a diffractometer and the classical powder method with copper Ka1 radiation (Å = 1.5406 Å).

[0175] The reduction rate was calculated by calculating the area of ​​the Ni line 0 located around 52°20, on all the diffractograms of each analyzed catalyst sample, then subtracting the signal present from room temperature below the 52° line which is due to alumina.

[0176] At room temperature on all catalysts, after calcination, containing copper and nickel, we detect alumina in delta and theta form, and large NiO and CuO lines.

[0177] In order to assess the reducibility rate and therefore the formation of Ni 0 , we measure the area of ​​the Ni line 0 located around 52°20, across all diffractograms, by subtracting the signal present even at room temperature below the 52° line, which is due to alumina. The relative percentage of Ni can thus be determined. 0 crystallized after reduction.

[0178] Table 1 below summarizes the reducibility rates, or Ni° content, for all catalysts characterized by XRD after reduction at 450°C for 90 minutes under a hydrogen flow. These values ​​were also compared with the reduction rate obtained for catalyst A (Ni alone) after a conventional reduction step (i.e., at a temperature of 400°C for 15 hours under a hydrogen flow).

[0179] Table 1 Tl

[0180] It was observed that adding a small amount of copper (0.1% by weight) did not significantly reduce the active nickel phase; only 60% by weight of nickel remained in metallic form after a reduction treatment at 450°C for 90 minutes (catalyst D). Furthermore, adding too much copper (1.5% by weight) resulted in an increase in the particle size of the active nickel phase (catalyst E).

[0181] Example 9: Reduction followed by comparative activity tests

[0182] Catalysts A to E are then tested in a batch reaction system representative of the hydrogenation of the final olefins in the alcohol-to-jet (ATJ) chain described previously. This is achieved using a feedstock consisting of 20% by weight of technical-grade diisobutene resold by Merck (97% purity), diluted in n-decane (Fisher, 99%). The catalysts are loaded into an autoclave via transfer under an inert atmosphere after the reduction step described in Example 8 for each catalyst A to E. Hydrogen is introduced at 3.5 MPa and 50°C with mechanical stirring, and the conversion rate of the olefins present in the diisobutene mixture is monitored over time by successive liquid samples analyzed by gas chromatography.A first-order model is fitted to the olefin conversion curve with respect to the feedstock olefins. Comparing the fitted kinetic constant for each test provides a ranking of the different catalysts in terms of activity. The results are presented in Table 2 below.

[0183] Table 2

[0184] In Table 2 above, the activity of catalyst A, reduced at 450°C for 15 hours, serves as a baseline for evaluating the activity of the other catalysts used in the hydrogenation reaction. An increase in activity is observed in the presence of catalysts B and C, even though the reduction time is considerably shorter (90 minutes instead of 15 hours). The use of catalyst E in the hydrogenation process does not yield better results in terms of activity because the excess copper reduces the surface area of ​​reduced nickel due to the formation of larger nickel nanoparticles during the preparation process. The use of catalyst D does not give good results because the low copper content is insufficient to reduce the nickel adequately.

Claims

DEMANDS 1. Process for hydrogenating olefins contained in a middle distillate olefin feedstock originating at least in part from a renewable source at a pressure between 0.1 MPa and 10 MPa, at a temperature between 25°C and 200°C, and at a VVH between 0.25 h' 1 and 8 p.m. 1 in the presence of a catalyst comprising nickel and copper, at a rate of 10% and 50% by weight of nickel element relative to the total weight of the catalyst, and at a rate of 0.15% and 1.3% by weight of copper element relative to the total weight of the catalyst, and a support comprising alumina.

2. A method according to claim 1, wherein said olefinic feed comprises at least 80% by weight of C5+ olefins relative to the total weight of olefins contained in said olefinic feed.

3. A method according to any one of claims 1 or 2, wherein said olefinic feed comprises at most 50% by weight of C4 to C8 olefinic compounds, and at least 50% by weight of C10+ olefinic compounds relative to the total weight of said olefinic feed.

4. A process according to any one of the preceding claims, 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.

5. A process according to any one of the preceding claims, wherein said olefinic charge is obtained from alcohol of renewable C2 origin.

6. A process according to the preceding claim, wherein said olefinic feedstock is obtained from C2 renewable alcohol obtained by at least the following steps: i) a dehydration step of C2 renewable alcohol to produce a C2 olefinic feedstock; ii) a first oligomerization step of said C2 olefinic feedstock to obtain at least one olefinic effluent comprising at least 80% by weight of C4+ olefins relative to the total weight of olefins contained in said olefinic effluent; iii) a second oligomerization step of at least part of the olefinic effluent obtained at the end of step ii) to obtain said olefinic feed of the middle distillates type, iv) optionally, a fractionation step of said olefinic feed of the middle distillates type obtained at the end of step iii) to obtain at least one gasoline cut and at least one cut of middle distillates (diesel and / or kerosene).

7. A method according to any one of the preceding claims, wherein said catalyst comprises a copper content of between 0.25 and 0.45% as elemental copper relative to the total weight of the catalyst.

8. A method according to any one of the preceding claims, wherein said catalyst comprises a nickel content of between 13% and 27% as elemental nickel relative to the total weight of the catalyst.

9. A method according to any one of the preceding claims, wherein the size of the nickel particles in said catalyst is less than 6 nm.

10. A method according to any one of the preceding claims, wherein said catalyst comprises a support having a specific surface area of ​​between 10 and 220 m² 2 / g.

11. A process according to any one of the preceding claims, wherein said catalyst is obtained by a preparation process comprising at least the following steps: a) the following sub-steps are carried out in sequence: a1) a solution comprising at least one nickel precursor and at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function are brought into contact with the alumina support to obtain a catalyst precursor; a2) the catalyst precursor obtained at the end of step a1) is dried at a temperature below 250°C; a3) the dried catalyst precursor obtained at the end of step a2) is calcined at a temperature between 250°C and 600°C;b) the following sub-steps are carried out in sequence: b1) the alumina support is contacted with at least one solution containing at least one copper precursor and one nickel precursor; b2) the catalyst precursor obtained at the end of step b1 is dried at least once at a temperature below 250°C; b3) the dried catalyst precursor obtained at the end of step b2 is calcined at a temperature between 250°C and 600°C; steps a) and b) being carried out separately in any order.

12. A process according to claim 11, further comprising a reduction step c) in which the catalyst obtained at the end of the sequence of steps a) and b), or b) and a), is reduced by bringing said catalyst into contact with a reducing gas at a temperature greater than or equal to 250°C and less than or equal to 500°C for a period greater than or equal to 5 minutes and less than 3 hours.

13. A process according to any one of claims 11 or 12, wherein the organic compound of substep a1) is selected from oxalic acid, malonic acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, levulinic acid, ethylene glycol, propane-1,3-diol, butane-1,4-diol, glycerol, xylitol, mannitol, sorbitol, diethylene glycol, triethylene glycol, glucose, gamma-valerolactone, dimethyl carbonate, diethyl carbonate, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylmethanamide, 2-pyrrolidone, γ-lactam, lactamide, urea, alanine, arginine, lysine, proline, serine, EDTA.

14. A process according to any one of claims 11 to 13, wherein the molar ratio between nickel and copper supplied in substep b1) is between 0.5 and 3 mol / mol.

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