A method for producing middle distillates, particularly kerosene, from alcohol-supplying raw materials.

Abstract

A method for producing a middle distillate type hydrocarbon base from an alcohol-based feedstock, comprising: a) the production of at least one dehydrated effluent containing at least 80% by weight of ethylene and a compound having at least three carbon atoms, relative to the total weight of the alcohol-based feedstock and considered dry, wherein the dehydration step is carried out in the presence of an acidic amorphous catalyst or an acidic zeolite catalyst; b) the separation of the dehydrated effluent obtained in step a), and the production of at least a fraction essentially containing ethylene and a fraction essentially containing a compound having at least three carbon atoms; and c) the first oligomerization of at least a portion of the fraction essentially containing ethylene resulting from step b), and at least olefin A method for producing an olefin-based effluent, comprising: step c) a first oligomerization step, wherein the olefin-based effluent contains at least 80% by weight of an olefin having 4 or more carbon atoms relative to the total weight of the olefin contained in the olefin-based effluent, wherein step c) is performed in the presence of a homogeneous catalyst; d) a second oligomerization step, wherein the effluent is produced from at least a portion of the effluent from step c) and a portion of the fraction from step b) that essentially contains a compound having at least 3 carbon atoms, wherein step d) is performed in the presence of an amorphous or zeolite heterogeneous catalyst; and e) a fractionation step of the middle distillate-type effluent produced from step d).

Description

[Technical Field]

[0001] The present invention relates to the conversion of an alcohol-based feedstock, more particularly an ethanol-based feedstock, preferably a middle distillate of bioethanol, to a diesel and / or kerosene fuel base, by a method comprising a dehydration step of the feedstock and two successive oligomerization steps. [Background technology]

[0002] The demand for the use of biomass as at least a partial replacement for petroleum resources in fuel synthesis is increasing. Therefore, the use of bioethanol for fuel base synthesis is attracting increasing attention.

[0003] Bioethanol is ethanol of agricultural origin, meaning it is produced from renewable sources such as biomass, including living plant materials.

[0004] Today, most bioethanol is produced by the fermentation of sugars contained in plant-derived starting materials. Starting with sugar-producing plants, the first step in the conversion is to obtain a sugar solution by extracting with hot water in the case of beets, or by crushing and pressurizing in the case of sugarcane. After concentration as needed, these sugar solutions or syrups are introduced into fermenters, where the biological conversion of sugars to ethanol takes place under the action of microorganisms (yeast) along with the simultaneous production of CO2. The resulting wine contains about 10% alcohol in water. The distillation step allows for the attainment of an azeotropic composition of ethanol / water (8% water). To obtain complete dehydration, it is necessary to pass through molecular sieves. In cereal plants (corn, wheat), the sugars that can be fermented to obtain ethanol exist in the form of a polymer called starch, and a preliminary step of enzyme-catalyzed hydrolysis is required to release them.

[0005] Technologies that enable the conversion of lignocellulosic biomass (such as wood, grass, straw, and other agricultural waste) into bioethanol have also recently become available. These technologies allow for the use of resources that do not compete with human or animal (in the sense of livestock farming) consumption.

[0006] There are also technologies that start with exhaust gases from the steel industry or the incineration of household waste, utilize the gasification of these wastes, and then use microbial fermentation, starting with the input of CO and some of the CO2 from the gas, as well as nutrients for microorganisms, to obtain ethanol.

[0007] The use of ethanol is inherently intended for the production of gasoline, not diesel or kerosene. Another very promising route is the use of ethanol as a biofuel in diesel engines. Biofuel E-Diesel is a mixture containing 85% to 95% diesel, anhydrous (water-free) ethanol, and a specially manufactured additive package for the stability of the mixture and to overcome some of the drawbacks of bioethanol, such as its low cetane number or low lubricity.

[0008] By mixing conventional diesel with ethanol and additives, combustion behavior is improved and the volatility of the fuel is slightly increased. The main result is a reduction in the emission of regulated pollutants such as particulate matter (PM10) and smoke. This reduction is due to the oxygen content of the biofuel, which limits the formation of particles during combustion. This is because these oxygen-containing molecules allow for a substantial improvement in the quality of combustion due to the presence of an oxidizer at the very site where the oxidation reaction occurs. Mixing bioethanol with diesel also has the main result and drawback of lowering the flash point.

[0009] Mixing conventional jet fuel (referred to as Jet A1 in customs declarations) with ethanol is not accepted by component manufacturers within 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 fly small aircraft on ethanol, its use in existing aircraft is simply not feasible.

[0010] Therefore, the conversion of ethanol to hydrocarbons is a favorable route for upgrading renewable resources toward fuel.

[0011] The literature is very rich in the conversion of methanol-type alcohols to olefins or aromatics, for example, using acidic catalysts, often zeolite catalysts, for the production of gasoline cuts.

[0012] The production of ethylene from ethanol is a known method and has been developed on an industrial scale across several units. Therefore, a unit for dehydrating ethanol to obtain ethylene was built in Brazil in the 1970s after the oil crisis. Ethanol is catalytically converted to ethylene from 300°C. The catalysts used can be catalysts of different properties, such as activated alumina or silica-alumina.

[0013] Scientific Design Inc. developed a unique technology for dehydrating ethanol to obtain ethylene and, following the development of a new catalyst introduced into industrial units, published the paper ("Ethylene from Ethanol", NK Kochar, R. Merims and ASPadia, CEP, June 1981). U.S. Patents 4,232,179, 4,396,789, 4,234,752, 4,396,789 and 4,698,452 may also be cited.

[0014] The documents, namely French Patent Nos. 2959750 and 2959752 in the name of IFPEN, disclose a process for producing middle distillate-type hydrocarbon bases starting from an ethanol feedstock, comprising a step of dehydrating ethanol, followed by two oligomerization steps in the homogeneous phase and the heterogeneous phase respectively. U.S. Patent No. 9840676 discloses a process for converting ethanol to diesel and / or kerosene by dehydration, conversion of the resulting ethylene to hexene, followed by dimerization or trimerization, to obtain a mixture containing C12 hydrocarbon compounds. None of these documents disclose a step of upgrading compounds having 3 or more carbon atoms (C3+ compounds) in the dehydration effluent, which are regarded as undesirable compounds.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Non-Patent Documents

[0016]

Non-Patent Document 1

[0017] Accordingly, an object of the present invention is to provide a process for producing middle distillate hydrocarbon bases (gas oil and / or kerosene), preferably kerosene bases, which can be incorporated into the fuel pool in a higher yield than prior art processes, starting from an alcohol-based feedstock, preferentially an ethanol feedstock produced from a renewable source obtained from biomass, also known as bioethanol.

[0018] The applicant's company has surprisingly demonstrated that by upgrading the C3+ compounds formed during the stage of dehydration of the alcohol-based feedstock, by sending them to a heterogeneous phase oligomerization stage, the yield of olefins advantageous for the production of middle distillates, more particularly kerosene, is increased (on the order of 0.5% to 10% of the carbon yield of the conversion). The above advantage is mainly an economic advantage by upgrading initially undesirable compounds after dehydration. MEANS FOR SOLVING THE PROBLEMS

[0019] The present invention is a process for producing a middle distillate type hydrocarbon base, preferably a kerosene hydrocarbon base, starting from an alcohol-based feedstock, comprising at least one monoalcohol, preferably comprising ethanol, a) dehydration of an alcohol-based feedstock comprising at least one monoalcohol, preferably comprising ethanol, and - at least 80% by weight, preferably at least 85% by weight, in a preferred manner at least 90% by weight of ethylene, relative to the total weight of the effluent considered to be dry, - A compound having at least 3 carbon atoms (C3+ compound), preferably a compound having 3 to 9 carbon atoms, and preferably a compound having 3 to 6 carbon atoms. a) a step in the production of at least a dehydrated effluent, Step a) is performed in the presence of an acidic amorphous catalyst or an acidic zeolite catalyst, b) Separation of the dewatered effluent obtained in step a), and at least - Fractions that essentially contain ethylene, - A fraction essentially comprising compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms. The manufacturing stage b) and c) A first oligomerization of at least a portion of the ethylene-containing fraction resulting from step b), and the production of at least an olefinic effluent, wherein the olefinic effluent contains at least 80% by weight of an olefin having 4 or more carbon atoms, relative to the total weight of the olefins contained in the olefinic effluent, and step c) wherein the first oligomerization step is carried out in the presence of a homogeneous catalyst, d) At least, - A portion of the spillage generated from stage c), - A fraction essentially comprising a compound having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, resulting from step b). The second oligomerization and the production of a middle distillate type effluent (d) Step d) is performed in the presence of an amorphous or zeolite heterogeneous catalyst, e) Fractionation of the middle distillate type effluent resulting from step d) and This includes methods.

[0020] "Considered dry" is understood to mean effluent that has been ideally separated from any solvents that may have been added prior to the dehydration step, in addition to the water and / or alcohol-based feedstock produced during the dehydration reaction. [Modes for carrying out the invention]

[0021] According to the present invention, the expressions "between... and..." and "between... and..." are equivalent and mean that the interval limit value falls within the range of values ​​stated. If this is not the case, and if the limit value does not fall within the range of values ​​stated, such details are provided by the present invention.

[0022] Within the scope of the present invention, various parameter ranges for a given stage, such as pressure ranges and temperature ranges, can be used individually or in combination. For example, within the scope of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0023] Next, specific embodiments of the present invention may be described. They may be implemented separately or in combination, without limiting the combination, where technically feasible.

[0024] feedstock According to the present invention, the feedstock processed by the method according to the present invention is an alcohol-based feedstock (or alcohol feedstock) containing at least one monoalcohol. Preferably, the monoalcohol is ethanol.

[0025] Advantageously, the alcohol feedstock of the method according to the present invention contains at least 35% by weight of monoalcohol, preferably 35% to 99.9% by weight of monoalcohol. The alcohol feedstock may also contain 0% to 65% water. The alcohol feedstock may also contain inorganic (Na, Ca, P, Al, Si, K, SO4, etc.) or organic impurities, such as monoalcohols other than the target monoalcohol, for example methanol or n-butanol in the ethanol feedstock, aldehydes, ketones and corresponding acids, such as furan acids, acetic acid or isobutyric acid. The alcohol feedstock may also contain, in particular, inorganic nitrogen-containing and / or sulfur-containing compounds, such as ammonia, or organic, preferably basic, nitrogen-containing and / or sulfur-containing compounds, such as amines, amides, imines and sulfur-containing compounds (thiols, thiophenes, mercaptans, thioethers, sulfides, disulfides, etc.). The organic and inorganic nitrogen and sulfur content in the alcohol-based feedstock is preferably 0.5% by weight or less, and more preferably 0.2% by weight or less, each expressed as a percentage of the total weight of the alcohol-based feedstock. According to the present invention, "nitrogen content" and "sulfur content" should be understood to mean the content of elemental nitrogen and elemental sulfur, respectively, contributed by nitrogen-containing impurities and sulfur-containing impurities present in the stream under consideration, particularly in the alcohol-based feedstock of the method of the present invention. Preferably, the elemental nitrogen content is advantageously determined by detection by combustion and chemiluminescence, and the elemental sulfur content is determined by detection by combustion and UV fluorescence.

[0026] Advantageously, the alcoholic feedstock may be derived from non-fossil resources. Preferably, the alcoholic feedstock processed by the method according to the present invention is produced from renewable resources obtained from biomass, preferably by fermentation of sugars obtained from sugar-producing plant crops such as sugarcane (sucrose, glucose, fructose) or beets, or similarly by fermentation of sugars obtained from starchy plants (starch) or lignocellulosic biomass or hydrolyzed cellulose (glucose dominant, and xylose, galactose), and contains a variable amount of water. For a more complete description of conventional fermentation methods, see "Les Biocarburants, Etat des lieux, perspectives et enjeux du developmentpement [Biofuels, Current State, Prospects and Developmental Challenges]", Daniel Ballerini, published by Technip.

[0027] Alcohol-based feedstocks can also be advantageously obtained from synthesis gas.

[0028] The alcohol-based feedstock processed by the method according to the present invention may also optionally be obtained by alcohol synthesis methods starting from fossil resources, such as coal, natural gas, or carbon waste.

[0029] The alcohol-based feedstocks of the method according to the present invention can also be obtained by the hydrogenation of the corresponding acid or ester. In this case, ethanol is preferably obtained by hydrogenating acetic acid or an acetic acid ester with hydrogen. Acetic acid can be obtained, for example, by carbonylation of methanol or fermentation of carbohydrates.

[0030] More preferably, the alcohol-based feedstock processed by the method according to the present invention is an alcohol-based feedstock produced from renewable resources obtained from biomass, more specifically from bioethanol.

[0031] In one embodiment, an alcohol-based feedstock can be subjected to a pretreatment step to produce a pretreated alcohol-based feedstock.

[0032] The pretreatment step is advantageously performed on at least one acidic solid. The acidic solid can be selected from all solids known to those skilled in the art. Thus, the acidic solid can be selected from the group consisting of acidic clay, zeolite, sulfated zirconia, acidic resin, and the like. For example, the acidic solid can be selected from commercially available acidic solids, such as clay treated with acid to make it acidic (e.g., montmorillonite) and preferably zeolite having a silica-to-alumina molar ratio of 2.5 to 100 in its crystal lattice.

[0033] Preferably, the acidic solid contains at least 0.1 mmol H + An acidic resin having an exchange capacity (or acid strength) of equivalents / gram, particularly an ion exchange resin, preferably a cation exchange resin, wherein the exchange capacity (or acid strength) is Na + H released by the acidic resin after exchange with ions + The acidity is determined by quantitative measurement of ions, preferably by conductivity measurement (see ASTM D4266 in particular). For example, the acidic solid is a commercially available acidic resin sold by Axens under the reference name TA801.

[0034] Advantageously, the pretreatment step allows for the capture and thus removal of cationic and optionally anionic impurities, basic, complexed or chelated impurities, inorganic or organic impurities, particularly metal salts (such as K, Na, Ca, Fe, Cu, P, or Cl salts), as well as nitrogen-containing and / or sulfur-containing impurities, such as ammonia, and / or basic organic entities, such as amines, amides, imines, or nitriles, that are present in the feedstock.

[0035] Advantageously, the alcohol-based feedstock is pretreated according to the teachings of French Patent Application Publication No. 3090393.

[0036] Operating conditions and catalyst Dehydration stage a) The method according to the present invention involves dehydrating an alcohol-based feedstock containing at least one monoalcohol, preferably ethanol, and - At least 80% by weight, preferably at least 85% by weight, and preferably at least 90% by weight of ethylene, based on the total weight of the spillage considered to be dry. - A compound having at least 3 carbon atoms (C3+ compound), preferably a compound having 3 to 9 carbon atoms, and preferably a compound having 3 to 6 carbon atoms. The process includes at least step a) of producing a dehydrated effluent, the dehydration step being carried out in the presence of an acidic amorphous catalyst or an acidic zeolite catalyst.

[0037] Non-limiting examples of compounds having three or more carbon atoms include olefins, such as propylene, linear butene, isobutene, methylbutene, and methylpentene; aromatics, such as toluene and xylene; and paraffins, such as propane, butane, pentane, and hexane.

[0038] Advantageously, the dehydrated effluent contains at least 1% by weight, preferably at least 5% by weight, and preferably at least 8% by weight, of compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, based on the total weight of the effluent considered to be dry. Very advantageously, the dehydrated effluent exhibits a content of compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, based on the total weight of the effluent considered to be dry, of less than 20% by weight, preferably less than 15% by weight, and preferably less than 10% by weight, of compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, based on the total weight of the effluent considered to be dry.

[0039] Advantageously, the compound having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, comprises an olefin, preferably at least 50% by weight, preferably at least 60% by weight, and more preferably at least 70% by weight, relative to the total weight of the compound having at least 3 carbon atoms.

[0040] In one embodiment, the dehydrated effluent contains, in addition to the olefin, 1% to 10% by weight of aromatic compounds, preferably compounds having at least three carbon atoms.

[0041] If the catalyst used in dehydration step a) is a zeolite catalyst, the catalyst comprises at least one zeolite selected from zeolites having pore openings (8MR, 10MR, or 12MR) containing 8, 10, or 12 oxygen atoms. This is because the size of the pores of a zeolite is known to be defined by the number of oxygen atoms that form the ring portion of the channel of the zeolite, called a "membered ring" or MR. Preferably, the zeolite dehydration catalyst comprises at least one zeolite exhibiting a structural type selected from MFI, FAU, MOR, FER, SAPO, TON, CHA, EUO, MEL, and BEA structural types. Preferably, the zeolite dehydration catalyst comprises a zeolite of the MFI structural type, preferably ZSM-5 zeolite.

[0042] Zeolites can be advantageously modified by dealuminization or desilicification according to any dealuminization or desilicification method known to those skilled in the art.

[0043] Zeolites can be modified with agents that can advantageously reduce their total acidity and improve their hydrothermal resistance properties. Preferably, the zeolite or catalyst is advantageously phosphorus-containing, preferably in the form of H3PO4, followed by steam treatment after neutralizing excess acid with a basic precursor, such as calcium Ca. Preferably, the zeolite contains 1% to 4.5% by weight, preferably 1.5% to 3.1% by weight, of phosphorus relative to the total weight of the catalyst.

[0044] If the catalyst used in dehydration step a) is an acidic amorphous catalyst, the catalyst comprises at least one porous refractory oxide selected from alumina, alumina activated by inorganic acid deposition, and silica-alumina.

[0045] The amorphous or zeolite dehydration catalyst used in step a) of the method according to the present invention may also advantageously include at least one oxide-type matrix, also called a binder. According to the present invention, the matrix is ​​understood to mean an amorphous or low-crystalline matrix.

[0046] The matrix is ​​advantageously selected from elements of the group formed by clay (e.g., from natural clays such as kaolin or bentonite), magnesia, alumina, silica, silica-alumina, aluminate, titanium oxide, boron oxide, zirconia, aluminum phosphate, titanium phosphate, zirconium phosphate, and charcoal. Preferably, the matrix is ​​selected from elements of the group formed by alumina, silica, and clay.

[0047] The dehydration catalyst used in step a) of the method according to the present invention is advantageously molded into the form of granules of various shapes and sizes. Advantageously, it is used in the form of linear or twisted cylindrical extrudes or multi-lobed extrudes, such as two-lobed, three-lobed, or multi-lobed extrudes, but optionally it may be manufactured and used in the form of crushed powder, rhomboids, rings, beads, wheels, spheres, or star shapes. Preferably, the catalyst is in the form of extruded or bead forms.

[0048] The dehydration step a) of the method according to the present invention is preferably performed at a temperature of 250°C to 600°C, preferably 300°C to 600°C, and preferably 300°C to 500°C, at an absolute pressure of 0.1 to 5 MPa, preferably 0.1 to 2.5 MPa, and preferably 0.1 to 1 MPa, for 0.1 to 50 hours. -1 , and preferably 0.5 to 15 hours -1 It operates at a weight-per-space velocity.

[0049] The space-time velocity per unit weight is defined as the ratio of the weight flow rate of the inflow feed material in step a) to the weight of the catalyst.

[0050] The conversion of the alcohol-based feedstock in step a) is advantageously over 90%, preferably over 95%, and preferably over 98%.

[0051] The conversion of the alcohol-based feedstock is understood to mean the ratio of the difference between the weight flow rate of the alcohol-based feedstock at the inlet in step a) and the weight flow rate of the alcohol-based feedstock at the outlet, with respect to the weight flow rate of the alcohol-based feedstock at the inlet, and the ratio is expressed as a percentage.

[0052] Advantageously, prior to separation step b), the water present in the dewatered effluent is separated by any method known to those skilled in the art.

[0053] The dehydration step a) can be advantageously carried out in accordance with the teachings in International Publication Nos. 2014083260 and International Publication Nos. 2014083261.

[0054] An example of a dehydration method for alcohol-based feedstocks is the Atol® method, which is commercially available from Axens.

[0055] Separation stage b) The method according to the present invention involves separating the dewatered effluent obtained in step a), and at least - Fractions that essentially contain ethylene, - A fraction essentially comprising compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms. This includes manufacturing step b).

[0056] "Essentially" is understood to mean that the fraction considered contains at least 95% by weight, preferably at least 97% by weight, and preferably at least 99% by weight of the desired compound, relative to the total weight of the fraction.

[0057] Advantageously, the compound having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, comprises an olefin, preferably at least 50% by weight, preferably at least 60% by weight, and more preferably at least 70% by weight, relative to the total weight of the compound having at least 3 carbon atoms.

[0058] In certain embodiments of the present invention, a fraction essentially comprising a compound having at least three carbon atoms is at least -Olefin fraction essentially containing olefins having 3 to 6 carbon atoms, -Preferably a heavy fraction containing aromatics having 6 to 9 carbon atoms. It is subjected to an additional separation step to obtain [the desired result].

[0059] In this particular embodiment, the fraction sent to the second oligomerization step d) is an olefin fraction essentially containing an olefin having 3 to 6 carbon atoms. The aromatic heavy fraction, preferably having 6 to 9 carbon atoms, may also contain unsaturated olefinic or diolefinic compounds, preferably having 6 to 9 carbon atoms. The heavy fraction is advantageously subjected to a step of selective hydrogenation of the unsaturated olefinic or diolefinic compounds contained in the fraction, and the resulting effluent is then sent to fractionation step e). The selective hydrogenation step of the heavy fraction allows for the purification of this fraction to improve its stability against oxidation. This is because the presence of heavy olefins makes the heavy fraction susceptible to peroxidation, ultimately resulting in the presence of gum in the final fuel.

[0060] The separation step b) can be carried out by any method known to those skilled in the art, for example, by distillation, particularly by continuous distillation, sequential distillation, or continuous or batch multicut distillation, with optional sidestream extraction to extract the intermediate boiling point cut. This separation can also be carried out using a column with an inner wall to reduce energy consumption. Molecular sieves or separation membranes can also be used to supplement or replace the distillation method.

[0061] Preferably, the dehydrated effluent resulting from step a) is subjected to at least one purification step of the effluent before the separation step b). This purification step allows for the removal of impurities harmful to the oligomerization catalyst used in the implementation of steps c) and d) located downstream, and in particular, allows for the removal of oxygen-containing compounds present in the dehydrated effluent.

[0062] An optional purification step can be advantageously carried out according to any method known to those skilled in the art, for example, a sequential combination of treatment in a water scrubbing column, followed by passage through an absorption column having MDEA (methyldiethylamine) or another amine, and passage through a scrubbing column having sodium hydroxide or any other means known to those skilled in the art. A dryer may be advantageously used to achieve a water content compatible with the oligomerization catalyst used downstream in oligomerization steps d) and e). The water content of the fraction sent to the first oligomerization step c) is advantageously 0 to 500 ppm, preferably less than 100 ppm, and very preferably less than 1 ppm.

[0063] First oligomerization stage c) The method according to the present invention comprises a first oligomerization of at least a portion of the ethylene-containing fraction resulting from step b), and a step c) of producing an olefinic effluent comprising at least 80% by weight, preferably 90% by weight, of olefins having 4 or more carbon atoms (C4+ compounds) relative to the total weight of the olefins contained in the olefinic effluent, wherein the first oligomerization step is carried out in the presence of a homogeneous catalyst.

[0064] Advantageously, at least a portion of the fraction essentially containing ethylene resulting from step b), i.e., at least 50% by weight, preferably at least 90% by weight, and preferably the entire fraction, is subjected to the first oligomerization step.

[0065] Advantageously, the olefinic effluent resulting from the first oligomerization step c) contains less than 20% by weight, preferably less than 10% by weight, of ethylene that was not converted during the first oligomerization step c), the percentage being expressed as a weight percentage of the total weight of olefins contained in the produced olefinic effluent.

[0066] In certain embodiments, the olefinic effluent is rich in olefinic hydrocarbons having 4 to 8 carbon atoms and also includes olefinic hydrocarbons (C10+ compounds) having at least 10 carbon atoms. More specifically, the olefinic effluent produced during the first oligomerization step c) preferably contains at least 80% by weight, preferably at least 90% by weight, of olefinic compounds mainly having 4 to 8 carbon atoms, and less than 20% by weight, preferably less than 10% by weight, of olefinic compounds mainly having 10 or more carbon atoms, the weight percentages being expressed relative to the total weight of olefins contained in the produced olefinic effluent.

[0067] According to step c) of the method according to the present invention, the catalyst used in the first oligomerization step c) is a homogeneous catalyst, that is, the catalyst is soluble in the liquid phase containing dissolved ethylene and its oligomerized product.

[0068] Advantageously, the homogeneous catalyst used in the oligomerization step c) of the method according to the present invention is -(+II) At least one precursor of nickel in the oxidized state, - and at least one activator selected from the group formed by chlorinated and brominated hydrocarbyl aluminum compounds, which is incorporated alone or in mixtures. Includes.

[0069] Optionally, the homogeneous catalyst used in oligomerization step c) of the method according to the present invention further comprises at least one organobrønsted acid, or at least one carboxylic acid anhydride, or at least one phosphine ligand of formula PR1R2R3, wherein the R1, R2, and R3 groups are identical or different from each other, linked or unlinked to each other.

[0070] The (+II) oxidized nickel compound is preferably a compound soluble in more than 1 gram / liter in a hydrocarbon medium, more specifically in the reactants and reaction medium, preferably nickel carboxylate of general formula (RCOO)2Ni, where R is a hydrocarbyl radical, for example, an alkyl, cycloalkyl, alkenyl, aryl, aralkyl or alkaryl radical containing up to 20 carbon atoms, preferably 5 to 20 carbon atoms in a hydrocarbyl residue. The R radical can be substituted with one or more halogen atoms, one or more hydroxyl, ketone, nitro or cyano groups, or other groups that do not interfere with the reaction. Two R radicals can also constitute an alkylene residue with 6 to 18 carbon atoms. The divalent nickel compound is advantageously selected from the following divalent nickel salts, namely octoate, 2-ethylhexanoate, decanoate, stearate, oleate, salicylate and hydroxydecanoate, taken individually or in mixtures, and preferably the divalent nickel compound is nickel 2-ethylhexanoate.

[0071] The activator is selected from the group formed by chlorinated and brominated hydrocarbyl aluminum compounds corresponding to formula AlRX2, where R is a hydrocarbyl radical and X is a halogen selected from chlorine and bromine, incorporated alone or in mixtures. The hydrocarbyl aluminum halides are advantageously selected from dichloroethylaluminum, dichloroisobutylaluminum, and dibromoethylaluminum. These hydrocarbyl aluminum dihalides can be advantageously concentrated with aluminum trihalides (AlX3), such as aluminum trichloride.

[0072] Brønsted organic acid compounds preferably correspond to formula HY, where Y is an organic anion, such as a carboxylic acid anion, a sulfonic acid anion, or a phenolic anion. The compounds preferably have a pKa of up to 3 at 20°C and are preferably selected from groups formed by halocarboxylic acids of formula RCOOH, where R is an alkyl halide radical, preferably an alkyl halide radical having at least one halogen atom at the α-position relative to the -COOH group and a total of 2 to 10 carbon atoms. Preferably, formula CX p H 3-p -COOH haloacetic acids are used, where X is fluorine, chlorine, bromine, or iodine, and p is an integer from 1 to 3. Examples include trifluoroacetic acid, difluoroacetic acid, fluoroacetic acid, trichloroacetic acid, dichloroacetic acid, or chloroacetic acid. These examples are not limiting, and aryl sulfonic acids, alkyl sulfonic acids, fluoroalkyl sulfonic acids, picric acid, or nitroacetic acid may also be used.

[0073] The catalyst used in the first oligomerization step c) may also contain at least one carboxylic acid anhydride of formula (RCO)2O, where R is a hydrocarbyl radical which may favorably contain one or more halogen atoms. The carboxylic acid anhydride is favorably selected from octanoic anhydride, 2-ethylhexanoic anhydride, decanoic anhydride, stearic acid anhydride, oleic acid anhydride, trifluoroacetic acid anhydride, monofluoroacetic acid anhydride, trichloroacetic acid anhydride, monochloroacetic acid anhydride, pentafluoropropionic acid anhydride, or heptafluorobutyric acid anhydride, which may be incorporated alone or in mixtures. Preferably, the carboxylic acid anhydride is trifluoroacetic acid anhydride.

[0074] Finally, the catalyst used in the first oligomerization step c) may also contain a phosphine ligand of formula PR1R2R3, where the R1, R2, and R3 groups are identical or different from each other, linked or unlinked. The hydrocarbyl groups R1, R2, and R3 of the phosphine ligand PR1R2R3 advantageously contain 1 to 20 carbon atoms, preferably 2 to 15 carbon atoms, and preferably 3 to 10 carbon atoms. Preferably, the hydrocarbyl groups R1, R2, and R3 of the phosphine ligand PR1R2R3 are selected from groups formed by methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, cyclopentyl, cyclohexyl, benzyl, and adamantyl groups.

[0075] Preconditioning of the catalyst can be performed before contacting the catalyst with ethylene. Preconditioning of the catalyst composition involves mixing the three components in a hydrocarbon solvent, such as an alkane or aromatic hydrocarbon, or a halogenated hydrocarbon, or preferably an olefin produced by an oligomerization reaction, under an inert atmosphere, such as under nitrogen or argon, at a controlled temperature of 0°C to 80°C, preferably 10°C to 60°C, for 1 minute to 5 hours, preferably 5 minutes to 1 hour, with stirring. Subsequently, the solution thus obtained is transferred to an oligomerization reactor under an inert atmosphere.

[0076] This preconditioning of the catalyst allows for increased catalytic activity in the oligomerization of ethylene.

[0077] The catalyst present in the unit performing oligomerization step c) is supplied in liquid form. Depending on the chemical composition of the catalyst, the weight proportion of each component of the catalyst should be controlled during the synthesis of the catalyst. The molar ratio of the hydrocarbyl aluminum halide to the nickel compound is expressed by the Al / Ni ratio, which is advantageously 2 / 1 to 50 / 1, preferably 2 / 1 to 20 / 1.

[0078] The molar ratio of Brønsted acid to the nickel compound is advantageously 0.25 / 1 to 10 / 1, preferably 0.25 / 1 to 5 / 1. If the catalyst contains a carboxylic acid anhydride, the molar ratio of the carboxylic acid anhydride to the nickel compound is advantageously 0.001 / 1 to 1 / 1, and very advantageously 0.01 / 1 to 0.5 / 1. If the catalyst contains a phosphine-type ligand, the molar ratio of the phosphine-type ligand to the nickel compound is advantageously 2 to 25, preferably 5 to 20, more preferably 5 to 15.

[0079] In one embodiment, the homogeneous catalyst is the catalyst described in International Publication No. 2017017087.

[0080] The first oligomerization step c), carried out by homogeneous catalytic action, is advantageously carried out continuously, i.e., a catalyst solution is injected into a unit carrying out the oligomerization step, and ethylene is continuously injected therein. The unit carrying out the step of oligomerization of ethylene by homogeneous catalytic action comprises one or more fully stirred reactors in series, and at least a portion of the effluent from the reactors is recycled back into the reactors, this recycling is advantageously cooled.

[0081] The first oligomerization step c) can be advantageously carried out in a reactor having one or more reaction steps in series, in which mainly ethylene-based feedstocks and / or a pre-conditioned catalyst composition are introduced sequentially into either the first step or the first step and any other one step.

[0082] The operating conditions in the reactor for step c) oligomerization by homogeneous catalytic action are such that the temperature is -20°C to +80°C and the pressure is sufficient to allow the presence of a liquid phase in the reactor. Preferably, the total absolute pressure in the reactor is 0.5 to 8 MPa.

[0083] At the exit of the first oligomerization step c), the homogeneous catalyst system is found as a mixture of the olefin effluent produced during step c) and unreacted ethylene.

[0084] Advantageously, the olefin effluent produced during the first oligomerization step c) is preferably subjected to at least step c') of treatment / separation of a homogeneous catalytic system from the effluent before being sent to the second oligomerization step d).

[0085] The treatment / separation step of the homogeneous catalytic system is understood to mean the step in which the catalytic system is deactivated and separated from the homogeneous reaction medium, particularly from the olefin effluent resulting from the first oligomerization step c). Step c' of the treatment / separation of the homogeneous catalytic system can be carried out using various methods known to those skilled in the art that are suitable for this treatment. Three non-limiting methods can be given below.

[0086] 1) Method using a trapping substance, 2) Or, a method of treating olefin effluents resulting from the first oligomerization step c) with a base and / or acid, which are either neutralized with a base or not neutralized with a base. 3) Alternatively, a method of separating the olefinic effluent generated from the first oligomerization step c), which is neutralized or not neutralized with a base, into a first effluent containing at least a portion of the C10+ olefinic compound and further a homogeneous catalyst system, and a second olefinic effluent not containing the catalyst system, and subsequently treating the effluent containing at least a portion of the C10+ compound and the homogeneous catalyst system by acidic and / or basic washing, or by using a capture substance.

[0087] Further details regarding this stage of processing / separation using a homogeneous catalytic system can be found in French Patent No. 2959752.

[0088] Advantageously, olefinic effluents optionally subjected to the treatment / separation step c') of a homogeneous catalytic system are sent to an optional separation step c), which enables the separation of the olefinic effluents resulting from the first oligomerization step c) or from the treatment / separation step c') of a homogeneous catalytic system into at least olefinic effluents containing compounds having four or more carbon atoms (C4+) and at least light C2 olefinic effluents.

[0089] The separation step c) can be advantageously carried out by any method known to those skilled in the art, such as a combination of distillation steps including, for example, one or more high-pressure and / or low-pressure and high-temperature and / or low-temperature knockout drums, and / or one or more distillation columns.

[0090] Light C2 olefin efflux is understood to mean efflux that favorably contains at least 50% by weight, preferably at least 65% by weight, of olefin compounds having fewer than 4 carbon atoms.

[0091] Advantageously, a portion, preferably all, of the light C2 olefin effluent is recycled to the first oligomerization step c).

[0092] Olefin leachates containing compounds with four or more carbon atoms (or C4+ olefin leachates) are understood to mean leachates favorably containing at least 80% by weight, preferably at least 90% by weight, of olefin compounds having four to eight carbon atoms (C4 to C8). C4+ olefin leachates may also contain olefin compounds having ten or more carbon atoms (C10+ compounds).

[0093] According to the first alternative form, if the olefinic effluent resulting from step c) or c') is subjected to an optional separation step c), then all of the C4+ olefinic effluent resulting from the optional separation step c), which includes C4-C8 olefinic compounds and optionally C10+ olefinic compounds, is advantageously sent to a second oligomerization step d).

[0094] According to the second alternative embodiment, even if the olefinic effluent resulting from step c) or c') is subjected to an optional separation step c), the C4+ olefinic effluent is advantageously separated in the second optional separation step c''') into at least an olefinic effluent containing compounds having 4-8 carbon atoms (C4-C8) and at least an olefinic effluent containing compounds having 10 or more carbon atoms (C10+ compounds). In this case, the C4-C8 olefinic effluent is advantageously sent to a second oligomerization step d), and the C10+ olefinic effluent is advantageously optionally hydrogenated and sent to fractionation step e). This embodiment makes it possible to limit the formation of heavy products (excluding kerosene cut) and thus increase the yield of kerosene cut. It also makes it possible to use a smaller reactor in the second oligomerization step d).

[0095] C4-C8 olefin leachates are defined as leachates containing olefin compounds distributed according to the following distribution, namely, at least 50% by weight, preferably at least 70% by weight, of olefin compounds having 4 to 8 carbon atoms, and less than 50% by weight, preferably less than 30% by weight, of other olefin compounds, where the weight percentage is expressed relative to the total weight of olefins present in the C4-C8 olefin leachates.

[0096] Similarly, a C10+ olefin leachate is defined as a leachate containing olefin compounds distributed according to the following distribution, namely, at least 50% by weight, preferably at least 70% by weight, of olefin compounds having 10 or more carbon atoms, and more favorably less than 50% by weight, preferably less than 30% by weight, of compounds having fewer than 10 carbon atoms, where the weight percentage is expressed relative to the total weight of olefins present in the C10+ olefin leachate.

[0097] Therefore, the raw materials supplied at the entrance to the second oligomerization step d) are advantageously, at least partially, - If the homogeneous catalytic treatment / separation step c') and / or the optional separation step c) are not performed between the first oligomerization step and the second oligomerization step, then all of the olefin effluent resulting from the first oligomerization step c) is, - If at least the treatment / separation step c') of a homogeneous catalytic system and the optional separation step c) are performed between the first oligomerization step and the second oligomerization step, then all or further of the C4+ olefin effluent (i.e., a portion of the olefin effluent resulting from the first oligomerization step c) separated from the light olefin effluent (C2-C4) may be removed. - If at least the treatment / separation step c') of a homogeneous catalytic system and two consecutive optional separation steps c) and c''') are performed between the first oligomerization step and the second oligomerization step, then all of the C4-C8 olefin effluents are removed. Includes.

[0098] An example of the first oligomerization step c) is the DimEne-B® method, which is commercially available from Axens.

[0099] Another example of the first oligomerization step c) is the Dimersol-E® method, which is commercially available from Axens.

[0100] Second oligomerization stage d) The method according to the present invention is at least - A portion of the olefin-based effluent generated from stage c), - A fraction essentially comprising a compound having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, resulting from step b). This includes the second oligomerization step d).

[0101] The second oligomerization step d) makes it possible to obtain a middle-distillate type effluent.

[0102] The second oligomerization step is carried out in the presence of an amorphous or zeolite heterogeneous catalyst.

[0103] According to a preferred embodiment, the catalyst used in the second oligomerization step d) comprises, preferably an amorphous heterogeneous catalyst, an amorphous inorganic material selected from silica-alumina and silica-containing alumina.

[0104] According to another preferred embodiment of the present invention, the second oligomerization step d) is carried out in the presence of a heterogeneous zeolite catalyst, i.e., a heterogeneous catalyst comprising at least one zeolite selected from aluminosilicate-type zeolites that preferably have at least pore openings (10MR or 12MR) containing 10 or 12 oxygen atoms and advantageously have an overall Si / Al molar ratio of 10 or more.

[0105] In one embodiment, the catalyst used in the second oligomerization step d) comprises at least one zeolite selected from MFI, MTW, MOR, TON, MEL, MFS, or MTT structural zeolites, which is incorporated either alone or in a mixture.

[0106] In a preferred embodiment, the catalyst used in the second oligomerization step d) comprises, either alone or in a mixture, at least one zeolite selected from ZSM-5, ZSM-12, NU-86, mordenite, ZSM-22, NU-10, ZBM-30, ZSM-48, ZSM-11, ZSM-57, IZM-2, ITQ-6, and IM-5 zeolites, preferably, at least one zeolite selected from ZSM-5, NU-10, and ZBM-30 zeolites, either alone or in a mixture, most preferably the zeolite being ZBM-30, and more preferably the zeolite being ZBM-30 synthesized in the presence of a triethylenetetramine structuring agent.

[0107] The zeolite used in the catalyst in step d) of the method according to the present invention may be advantageously subjected to several post-treatments known to those skilled in the art, such as being modified by dealuminulation or desilicification according to any dealuminulation, external passivation or desilicification method known to those skilled in the art, for the purpose of improving its activity and / or stability.

[0108] According to a very specific embodiment in which silica-alumina is used as a catalyst in the second oligomerization step d), silica-alumina enables the oligomerization of at least a portion of the effluent resulting from step c) and at least a portion of the fraction essentially containing a compound having at least three carbon atoms resulting from step b) with better control over the reactivity of the olefin, particularly enabling it to operate at a low conversion level per pass, and very advantageously, enables the optimization of selectivity for the desired olefin compared to oligomerization in the presence of other catalysts, e.g., zeolites. Furthermore, coke formation occurs in the presence of silica-alumina in smaller amounts and more slowly than in the presence of zeolites. Thus, silica-alumina requires regeneration less frequently than zeolites.

[0109] The catalyst used in step d) of the method according to the present invention also advantageously includes at least one oxide-type matrix, also called a binder. The matrix is ​​understood, according to the present invention, to mean an amorphous or low-crystalline matrix.

[0110] The matrix is ​​advantageously selected from elements of the group formed by clay (e.g., from natural clays such as kaolin or bentonite), magnesia, alumina, silica, silica-alumina, aluminate, titanium oxide, boron oxide, zirconia, aluminum phosphate, titanium phosphate, zirconium phosphate, and charcoal. Preferably, the matrix is ​​selected from elements of the group formed by alumina, clay, and silica; more preferably, the matrix is ​​selected from alumina; and even more preferably, the matrix is ​​γ-alumina.

[0111] The catalyst used in step d) of the process according to the invention is advantageously shaped into the form of granules (or particles) of various shapes and sizes. They are advantageously used in the form of linear or twisted cylindrical extrudates or multileaf extrudates, for example bilobal, trilobal or multileaf extrudates, but may optionally be produced and used in the form of crushed powder, rhomboids, rings, beads, wheels or spheres. Preferably, the catalyst is in the form of extrudates having a size of 1 to 10 mm.

[0112] The second oligomerization step d) is advantageously carried out in at least one fixed bed reactor.

[0113] In one embodiment, in the second oligomerization step d), at least a portion of the gasoline-type cut resulting from the fractionation step e) is also oligomerized.

[0114] The second oligomerization step d) of the process according to the invention is advantageously operated at a temperature of 50°C to 400°C, preferably 100°C to 350°C, and in a preferred manner 100°C to 300°C, at an absolute pressure of 2 to 15 MPa, preferably 2 to 8 MPa, and in a preferred manner 3 to 8 MPa, and at a weight hourly space velocity of 0.1 to 10 h -1 , and preferably 0.4 to 5 h -1 .

[0115] Here, the weight hourly space velocity is defined as the ratio of the weight flow rate of the "fresh" feedstock entering step d) to the weight of the catalyst, not including possible recycling.

[0116] The intermediate distillate effluent produced by the second oligomerization step d) is an olefinic effluent containing at least 80% by weight, preferably at least 90% by weight, of olefins, including less than 20%, preferably less than 10%, of C4 olefins (where C4 means containing 4 carbon atoms), particularly C4 olefins that were not converted during the second oligomerization step d), where the weight percentage is expressed relative to the total weight of olefins contained in the intermediate distillate effluent produced.

[0117] The middle distillate type effluent advantageously contains up to 50% by weight, preferably up to 40% by weight, of C4-C8 olefin compounds and at least 50% by weight, preferably at least 60% by weight, of C10+ olefin compounds (i.e., containing 10 or more carbon atoms), where the weight percentage is expressed relative to the total weight of olefins present in the effluent.

[0118] The method according to the present invention is flexible in that, by adjusting the operating conditions and the selection of a catalyst in the second oligomerization step d), the reaction can be directed towards one or the other of the target products, namely, in one case a diesel-type hydrocarbon base and in the other case a kerosene-type hydrocarbon base.

[0119] If it is more specifically required to produce a diesel-type hydrocarbon base, the second oligomerization step d) is performed in the presence of a catalyst containing at least one zeolite selected from aluminosilicate-type zeolites having an overall Si / Al ratio greater than 10 and a 10 or 12MR pore structure, at a temperature of 200°C to 300°C, a pressure of 3 to 7 MPa, and for 0.1 to 5 hours. -1 This is performed advantageously in terms of weight per spacetime velocity.

[0120] If it is more specifically required to produce a kerosene-type hydrocarbon base, the second oligomerization step d) preferably contains silica-alumina, and preferably in the presence of an amorphous catalyst consisting of silica-alumina, at a temperature of 100°C to 300°C, a pressure of 2 to 6 MPa, and for 0.1 to 5 hours.-1 This is performed advantageously in terms of weight per spacetime velocity.

[0121] An example of the second oligomerization step d) is the Polynaphta® method, which is commercially available from Axens.

[0122] Fractionation stage e) The method according to the present invention includes step e) fractionation of the middle distillate type effluent resulting from step d).

[0123] Fractionation step e) is advantageous in that the middle distillate effluent is cut at least twice. - Gasoline cut, - Middle distillate cut (diesel fuel and / or kerosene) The process is carried out in at least one distillation column to separate the components.

[0124] Light spills containing C2-C4 compounds can also be separated, either pure or as a mixture, for upgrading purposes.

[0125] Heavy fractions with initial boiling points of 350°C to 370°C can also be advantageously separated.

[0126] The term "gasoline cut" is understood to mean a cut that includes hydrocarbon compounds whose boiling point is between ambient temperature and 220°C.

[0127] The term "middle distillate cut" is understood to mean a cut that includes hydrocarbon compounds with boiling points between 140°C and 360°C.

[0128] At least a portion of the gasoline cut resulting from fractionation step e) can be advantageously recycled to the second oligomerization step d) of the method according to the present invention.

[0129] In one embodiment, C4 olefins that were not converted during the second oligomerization step d) are separated from the effluent resulting from step d) and then recycled to the inlet of the second oligomerization step d).

[0130] One of the objectives of the present invention is to maximize the yield of the middle distillate base, preferably the kerosene base, where undesirable light effluents (including C2-C4 compounds) and gasoline cuts (corresponding to C4-C8 compounds) are advantageously re-oligomerized in steps c) and d) of the method according to the present invention, respectively, enabling an increase in their molecular weight, and therefore an increase in boiling point and suitability for desired use.

[0131] At least a portion, preferably all, of the middle distillate cut (diesel and / or kerosene) resulting from fractionation step e) is subjected to an optional step f) of olefin hydrogenation to allow the middle distillate cut to be incorporated into the fuel pool. Preferably, at least a portion, preferably all, of the middle distillate cut (diesel and / or kerosene) resulting from fractionation step e) is brought into contact with a hydrogen-rich gas in the presence of a catalyst, taken alone or in a mixture, comprising at least one metal from Group VIII, preferably selected from palladium and nickel, and a support, preferably selected from alumina, silica, or silica-alumina.

[0132] The catalyst used in the optional hydrogenation step f) contains, favorably, 0.1% to 10% by weight of palladium and / or favorably, 1% to 60% by weight of nickel, relative to the total weight of the catalyst.

[0133] The optional hydrogenation step f) is advantageously performed at a temperature of 100°C to 250°C, a pressure of 2 to 5 MPa, and 0.05 to 8 hours at the reactor inlet. -1 It is executed at a mass per spacetime velocity.

[0134] The hydrogenation performance is confirmed by measuring the bromine number, which is advantageous when it is desirable to saturate all unsaturated compounds present in the cut being hydrogenated, with a maximum of 5 g Br / 100 g.

[0135] The spills resulting from the optional hydrogenation step f) mainly consist of hydrocarbons that can be upgraded and incorporated into a kerosene and / or diesel fuel pool, preferably a kerosene pool.

[0136] To enable fractionation of the effluent from step f) into kerosene cut and / or diesel cut and / or cuts having boiling points above 360°C, an optional final separation step g) may be advantageously performed after an optional hydrogenation step f).

[0137] The term "diesel fuel cut" is understood to mean the removal of hydrocarbon compounds whose boiling point is between 220°C and 360°C.

[0138] The term "kerosene cut" is understood to mean a cut that includes hydrocarbon compounds with a boiling point of 140°C to 300°C.

[0139] According to one embodiment, at least a portion of the effluent generated from an optional hydrogenation step f) constitutes a diluent of the feedstock for the first oligomerization step c) and can therefore be favorably recycled to the first oligomerization step c) in order to stabilize the catalyst.

[0140] If the desired fuel is kerosene, the olefin hydrogenation step is essential.

[0141] Examples Example: Method for producing intermediate distillates from ethanol supply raw materials: Stage a): Dehydration of the raw materials The supplied raw material is a bioethanol raw material with the following characteristics:

[0142] Sugarcane ethanol contains 92% by weight ethanol, 500 ppm by weight organic impurities (heavy alcohol, methanol, esters, acids), and the remainder is water.

[0143] This raw material is processed in the presence of zeolite catalyst PZSM-5 at a temperature of 400°C, a pressure of 0.6 MPa, and for 7 hours. -1 Dehydration occurs at a weight-per-time space velocity.

[0144] The composition of the dewatered effluent is shown in the table below:

[0145] [Table 1]

[0146] The composition of the C3+ compound is 74.3% by weight of olefins (20.1% propylene, 45.4% butene, 8.8% C5-C6 olefins), 19.9% ​​by weight of paraffins (13.5% C3-C4 paraffins, 6.4% C5-C6 paraffins), and 5.9% aromatics.

[0147] Separation stage b) The effluent is dried and compressed at 2.28 MPa, and CO, CO2, and acetaldehyde are removed by capture material and molecular sieves (Cu / Zn deoxygenating material, 3A and 13X sieves), before being introduced into a cryogenic distillation column. This column uses ordered packing to a height equivalent to 40 theoretical plates. At the top of the column, at -22°C, an ethylene-rich cut is produced, containing trace amounts of propylene. The bottom cut is separated in a second distillation column (20 theoretical plates) with a top pressure of 0.7 MPa and 30°C to produce a top fraction rich in C3-C5 compounds (ethylene-free) and an aromatic-rich bottom cut. The top cut from this second column is sent to oligomerization step d), and the bottom cut is used as fuel in the process furnace, in the inventors' case. The composition of the top cut is as follows:

[0148] [Table 2]

[0149] First oligomerization stage c) The ethylene-rich cut resulting from separation step b) is sent to the first oligomerization step c), which operates at a temperature of 50°C and a pressure of 1 MPa in the presence of a homogeneous catalyst containing a divalent nickel compound, together with a dichloroethylaluminum cocatalyst (EADC). The Al / Ni molar ratio is fixed at 15.

[0150] The composition of the C4+ compounds in the olefin effluent generated from step c) is shown in the table below:

[0151] [Table 3]

[0152] The different cut options are as follows: -41% by weight of C4 olefin, -35% by weight of C6 olefin, -14.5% by weight of C8 olefin, -9.5% by weight of C10+ olefin.

[0153] The outflow at the outlet of stage c) is cut into two sections: - The cut containing C4, C6 and C8 olefins is sent to step d). - A cut containing C10+ olefin is sent to step f). It separates into two parts.

[0154] Second oligomerization stage d) In Case 1 (a comparative example using the prior art), the cut containing C4, C6, and C8 olefins generated from the first oligomerization step c) is sent to step d).

[0155] In Case 2 (according to the present invention), the cut containing C4, C6, and C8 olefins obtained from the first oligomerization step c) is sent to step d) together with the fraction rich in C3-C5 compounds obtained from the separation step b).

[0156] The second oligomerization step d) is performed in the presence of an aluminosilicate heterogeneous catalyst, at a temperature of 110°C, an absolute pressure of 6.0 MPa, and for 0.2 hours. -1 It operates at a spatial velocity per hour.

[0157] The effluent from the second oligomerization is divided into two fractions in the first column: -C4 cuts that are recycled at the entrance of stage d) or come out of the process in the form of bleed, - C6+ cut sent to the second column It separates into two parts.

[0158] The C6+ cut resulting from this first column is divided into two fractions in the second column: - At the entrance of stage d), C6-C8 cuts are recycled or exit the process in the form of bleed. -Oligomerates sent to stage e) It separates into two parts.

[0159] The recycling rate of C6-C8 cuts originating from fractionation stage e) for the raw materials entering stage d) is 3.5.

[0160] The recycling rate of C4 compounds separated in step e) that are not converted in step d) for the raw materials entering step d) is 1.5.

[0161] The composition of the effluent resulting from the second oligomerization stage is shown in the table below:

[0162] [Table 4]

[0163] Hydrogenation and fractionation stage e): The oligomerate obtained in step d) is hydrogenated together with the C10+ olefin-containing cut produced from the first oligomerization step c) after separation. This step is carried out using a nickel-on-alumina catalyst at a temperature of 180°C, a pressure of 1.5 MPa, and for 0.5 hours. -1 It runs at a spatial velocity per hour.

[0164] The hydrogenated effluent is sent to a fractionation column where kerosene and diesel fuel are recovered.

[0165] The fuel yields of the effluents resulting from dehydrogenation and fractionation step e) are listed in the table below:

[0166] [Table 5]

[0167] The overall yield of the method is shown in the table below:

[0168] [Table 6]

[0169] It is observed that a +3.8% (54.3%-50.5%) relative to the weight of the feedstock, and to a lesser extent, a better yield of diesel fuel (+0.2% (2.6%-2.4%) relative to the weight of the feedstock entering the process, can be obtained.

Claims

1. A method for producing a middle distillate type hydrocarbon base, preferably a kerosene hydrocarbon base, starting from an alcohol-based feedstock, and containing at least one monoalcohol, preferably ethanol, wherein a) Dehydration of the alcohol-based feedstock containing at least one monoalcohol, preferably ethanol, and - At least 80% by weight, preferably at least 85% by weight, and preferably at least 90% by weight of ethylene, based on the total weight of the effluent considered to be dry. - Compounds having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms. Step a) of producing at least a dehydrated effluent, wherein the dehydration step is carried out in the presence of an acidic amorphous catalyst or an acidic zeolite catalyst, b) Separation of the dewatered effluent obtained in step a), and at least - Fractions that essentially contain ethylene, - A fraction essentially comprising a compound having at least three carbon atoms, preferably three to nine carbon atoms, and preferably three to six carbon atoms. The manufacturing stage b) and c) A first oligomerization of at least a portion of an ethylene-containing fraction resulting from step b), and the production of at least an olefinic effluent, wherein the olefinic effluent contains at least 80% by weight of an olefin having 4 or more carbon atoms, relative to the total weight of the olefins contained in the olefinic effluent, wherein the first oligomerization step is carried out in the presence of a homogeneous catalyst, d) At least, - A portion of the spillage generated from step c), - A fraction essentially comprising a compound having at least three carbon atoms, preferably three to nine carbon atoms, and preferably three to six carbon atoms, resulting from step b) Step d) of the second oligomerization and production of the middle distillate type effluent, Step d) wherein the second oligomerization step is carried out in the presence of an amorphous or zeolite heterogeneous catalyst, e) Fractionation stage of the middle distillate type effluent resulting from stage d) Methods that include...

2. The method according to claim 1, wherein the dewatered effluent contains, in a preferred manner, at least 1% by weight, preferably at least 5% by weight, and preferably at least 8% by weight, of a compound having at least 3 carbon atoms, preferably 3 to 9 carbon atoms, and preferably 3 to 6 carbon atoms, based on the total weight of the effluent deemed to be dry.

3. The method according to any one of the preceding claims, wherein the compound having at least three carbon atoms, preferably three to nine carbon atoms, and preferably three to six carbon atoms, comprises an olefin, preferably at least 50% by weight, preferably at least 60% by weight, and more preferably at least 70% by weight, of the total weight of the compound having at least three carbon atoms.

4. The fraction essentially comprising a compound having at least three carbon atoms resulting from step b) is at least -Olefin fraction essentially containing olefins having 3 to 6 carbon atoms, - Preferably a heavy fraction containing aromatics having 6 to 9 carbon atoms. The method according to any one of the prior claims, which is subjected to an additional separation step to obtain.

5. The method according to claim 4, wherein the heavy fraction is preferably subjected to a step of selective hydrogenation of an unsaturated olefin or diolefin compound contained in the fraction, and the resulting effluent is then sent to step e) fractionation.

6. The method according to any one of the preceding claims, wherein the olefin effluent produced from the first oligomerization step c) contains less than 20% by weight, preferably less than 10% by weight, of ethylene, the percentage being expressed as a weight percentage of the total weight of the olefin contained in the produced olefin effluent.

7. The homogeneous catalyst used in the oligomerization step c) is - (+II) oxidized nickel, at least one precursor - and at least one activator selected from the group formed by chlorinated and brominated hydrocarbyl aluminum compounds, which is incorporated alone or in mixtures. A method according to any one of the prior claims, including the method described in that claim.

8. The method according to any one of the preceding claims, wherein the olefin effluent generated from step c) is sent to a separation step c''), which enables the separation of the olefin effluent generated from the first oligomerization step c) into at least an olefin effluent containing a compound having four or more carbon atoms, and at least a light C2 olefin effluent.

9. The method according to claim 8, wherein a portion, preferably all, of the light C2 olefin-based effluent is recycled to the first oligomerization step c).

10. The method according to claim 8 or 9, wherein the olefin effluent containing a compound having four or more carbon atoms is separated in a second separation step c'') into at least an olefin effluent containing a compound having four to eight carbon atoms and at least an olefin effluent containing a compound having ten or more carbon atoms.

11. The method according to claim 10, wherein the olefin effluent containing a compound having 10 or more carbon atoms is hydrogenated and sent to the fractionation step e).

12. The method according to any one of the preceding claims, wherein the intermediate distillate effluent produced by the second oligomerization step d) is an olefinic effluent containing at least 80% by weight, preferably at least 90% by weight, of olefins, which include more than 4 carbon atoms and less than 20%, preferably less than 10%, of C4 olefins, the weight percentage being expressed with respect to the total weight of the olefins contained in the intermediate distillate effluent produced.

13. The fractionation step e) cuts the middle distillate-type effluent generated from step d) into at least two cuts. - Gasoline cut, - Middle distillate cut The method according to any one of the preceding claims, performed in at least one distillation column to separate into

14. The method according to claim 13, wherein at least a portion, preferably all, of the middle distillate cut resulting from the fractionation step e) is subjected to the hydrogenation step f) of the olefin.

15. The method according to any one of the preceding claims, wherein the C4 olefin that was not converted during the second oligomerization step d) is separated from the effluent resulting from step d) and then recycled to the inlet of the second oligomerization step d).

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