A method for producing aviation fuel from an olefin-containing feedstock, comprising an oligomerization step and a heterogeneous oligomerization step.
Patent Information
- Application Number
- JP2026518952
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-01-22
- Filing Date
- 2024-09-27
- Publication Date
- 2026-10-16
Smart Images
Figure 2026534489000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for producing aviation fuel, which includes converting light olefins into heavier olefins using oligomerization technology. [Background technology]
[0002] (Conventional technology) The demand for sustainable aviation fuel (SAF) is crucial to achieving the aviation industry's decarbonization targets. To meet the International Civil Aviation Organization's (ICAO) goal of limiting the net increase in carbon emissions from aviation after 2020, it is necessary to replace fossil fuel-derived kerosene with liquid fuels produced from bio-based carbon. By 2050, the global demand for SAF is estimated to reach approximately 500 million tons per year.
[0003] To achieve this goal, it is necessary to utilize various types of raw materials and, therefore, develop solutions for various technological transformations.
[0004] One known conversion route involves methanol, for example; several techniques exist for producing light olefins from methanol (the MTO (Methanol to Olefin) route).
[0005] More generally, there are numerous pathways for producing light olefins. The controlled oligomerization of these light olefins makes it possible to generate longer carbon chains, which can subsequently be involved in the composition of naphtha, gasoline, kerosene, or diesel fuel.
[0006] French Patent No. 2620724 describes a process for producing olefin oligomers that enables the production of premium grade gasoline, jet fuel, and automotive diesel fuel from C2-C8 light olefins using a heterogeneous oligomerization process. Any suitable source of olefins can be used as starting materials. They may be produced by catalytic decomposition of methanol. [Overview of the Initiative] [Problems that the invention aims to solve]
[0007] However, in the processes of prior art used to produce aviation fuel, oligomerizing ethylene with heavier olefins is difficult, and it is often proposed to recycle ethylene into upstream processes at the expense of carbon loss and additional operating costs.
[0008] The applicant has demonstrated that, remarkably, by separating the ethylene fraction from the feedstock and sending it to an oligomerization step, preferably an oligomerization step in a homogeneous phase, it is possible to convert it into a fluid of higher olefins (C4+) having four or more carbon atoms, which is then sent to a heterogeneous oligomerization step together with a fraction containing compounds (C3+) having three or more carbon atoms, thereby achieving very high selectivity for kerosene fractions that meet current standards, particularly ASTM D7566 or European Standard 15940, while simultaneously maintaining a satisfactory or high overall conversion rate of the olefinic feedstocks.
[0009] Therefore, by adding an oligomerization unit, preferably for oligomerizing ethylene in a homogeneous phase, to an aviation fuel production process that only has a heterogeneous oligomerization section, it becomes possible to upgrade the process by oligomerizing ethylene contained in olefin-based feedstocks, particularly that derived from methanol decomposition units (MTOs), independently of other olefins, and as a result convert it into more reactive olefins for the heterogeneous oligomerization process. [Means for solving the problem]
[0010] (Summary of the invention) The present invention relates to a method for producing aviation fuel from raw materials containing olefins, wherein the raw materials include the following components: -The olefin content is 50% by weight or more, preferably 65% by weight or more, preferably 80% by weight or more; - The ethylene content is less than 80% by weight, preferably less than 65% by weight, and preferably less than 50% by weight, relative to the total weight of the olefins in the raw material; The above manufacturing method includes the following steps: a) Fractionating the raw materials, at least -A first fraction containing at least 85% by weight, preferably at least 90% by weight, and preferably at least 95% by weight of the ethylene present in the raw material introduced in step a); - A second fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of compounds having at least three carbon atoms; The process of obtaining: b) A first oligomerization step, which oligomerizes at least a portion of the first fraction obtained in step a), to obtain a first effluent containing at least 60% by weight of olefins having 4 or more carbon atoms relative to the total weight of the olefins, and is carried out in the presence of an oligomerization catalyst; c) at least - A portion of the first outflow from process b), - Part of the second stroke from process a) A second oligomerization step, comprising oligomerizing the olefin, to obtain a second effluent containing at least 85% by weight, preferably at least 90% by weight, preferably at least 95% by weight, of olefins having 7 or more carbon atoms relative to the total weight of the olefin, the second oligomerization step being carried out in the presence of a heterogeneous amorphous catalyst or a heterogeneous zeolite catalyst; d) Hydrogenating the second effluent from step c) to obtain a third effluent containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight of paraffin; e) A step of fractionating the third effluent from step d) to obtain at least one aviation fuel fraction (cut). [Modes for carrying out the invention]
[0011] (Detailed description of the invention) According to the present invention, the expressions "between... and..." and "...~..." are synonymous, meaning that the limit value of the interval falls within the range of the stated values. If this is not the case, i.e., if the limit value does not fall within the range of the stated values, this is clarified by the present invention.
[0012] For the purposes of the present invention, various parameters in a given process, such as pressure ranges and temperature ranges, may be used individually or in combination. For example, for the purposes of the present invention, a preferred pressure range may be combined with a more preferred temperature range.
[0013] In this specification, the term "Cx" represents a hydrocarbon compound containing x carbon atoms. The term "Cx+" represents a hydrocarbon compound containing at least x carbon atoms. The term "Cx-" represents a hydrocarbon compound containing up to x carbon atoms. The term "Cx~Cy" represents a hydrocarbon compound having x to y carbon atoms.
[0014] Throughout this specification, groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, CRC Press, Editor-in-Chief DRLide, 81st edition, 2000-2001). For example, Group VIIIB according to the CAS classification corresponds to the metals in columns 8, 9, and 10 of the new IUPAC classification, and Group IB according to the CAS classification corresponds to the metals in column 11 of the new IUPAC classification. Hereinafter, specific embodiments of the present invention will be described. These embodiments may be implemented individually or in combination, and may be combined within the technically feasible range.
[0015] In this patent application, the term "to comprise" is synonymous with (means the same as) "to include" and "to contain", is inclusive or non-limiting, and does not exclude other elements that are not explicitly stated. The term "to comprise" is understood to encompass the exclusive and closed term "to consist of". [Feedstock] According to the present invention, the feedstock comprises olefins, and comprises the following components: - Olefins in an amount of 50% by weight or more, preferably 65% by weight or more, more preferably 80% by weight or more; - Ethylene in an amount of less than 80% by weight, preferably less than 65% by weight, more preferably less than 50% by weight, relative to the total weight of olefins in the feedstock.
[0016] The olefin-based feedstock of the present invention comprises ethylene, preferably at least 5% by weight of ethylene relative to the total weight of the feedstock.
[0017] Advantageously, the feedstock comprises ethylene in an amount of 2% to 30% by weight, preferably 5% to 25% by weight, more preferably 7% to 15% by weight, relative to the total weight of olefins contained in the feedstock.
[0018] Advantageously, the feedstock comprises propylene in an amount of more than 40% by weight, preferably more than 45% by weight, more preferably more than 50% by weight, relative to the total weight of olefins contained in the feedstock.
[0019] Advantageously, the feedstock comprises olefins having 2 to 6 carbon atoms in an amount of at least 50% by weight, preferably at least 65% by weight, more preferably at least 80% by weight, relative to the total weight of the feedstock.
[0020] Advantageously, the raw materials contain at least 80% by weight of a compound having 3 to 6 carbon atoms relative to the total weight of the raw materials.
[0021] Advantageously, the raw material contains olefins having 2 to 6 carbon atoms in an amount of at least 95% by weight, preferably at least 97% by weight, and preferably at least 98% by weight, relative to the total weight of olefins contained in the raw material.
[0022] Advantageously, the raw material contains olefins having 3 to 6 carbon atoms in an amount of at least 80% by weight relative to the total weight of olefins contained in the raw material.
[0023] Advantageously, the raw material is obtained from an alcohol catalytic decomposition unit, preferably a methanol or ethanol catalytic decomposition unit.
[0024] In one embodiment, the raw material further comprises dimethyl ether (DME).
[0025] In one embodiment, the raw material is obtained from an apparatus for decomposing and / or dehydrating heavy alcohols such as propanol or butanol, or from an FCC (fluid catalytic cracking) apparatus or a vapor cracking apparatus.
[0026] The raw materials are not supplied from the ethanol dehydration unit (ETE (ethanol to ethylene) pathway).
[0027] In one embodiment, the raw material may further include a compound having more than 6 carbon atoms, preferably a compound having 7 to 8 carbon atoms. [Operating conditions and catalyst] Fractionation process a) The method according to the present invention fractionates the raw material and at least -A first fraction containing at least 85%, preferably at least 90%, preferably at least 95% of the ethylene present in the raw material introduced in step a), - A second fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having at least 3 carbon atoms. This includes step a) obtaining
[0028] The fractionation step a) can be carried out by any method known to those skilled in the art, such as continuous distillation, continuous or batch distillation, and a method using lateral discharge for extracting the intermediate boiling fraction. This separation can also be performed with reduced energy consumption by using a column with an internal wall. In addition to, or instead of, the use of solutions using molecular sieves or separation membranes is also an option for separating the desired fraction.
[0029] In one embodiment, a heavy fraction is additionally obtained in step a), which contains at least 90% by weight, preferably at least 95% by weight, and preferably at least 98% by weight, of benzene and compounds heavier than benzene.
[0030] In one embodiment, all or part of the heavy fraction is sent to hydrogenation step d). The fractionation of the heavy fraction is performed with the aim of recovering the fraction containing compounds heavier than benzene, and at least a portion of the recovered fraction is sent to hydrogenation step d).
[0031] In one embodiment, a fraction containing at least 90%, preferably at least 95%, and preferably at least 98% of the dimethyl ether (DME) contained in the raw material introduced in step a) is additionally obtained in step a).
[0032] This fractionation step a) is advantageously designed to separate all compounds that may adversely affect the reaction and oligomerization catalyst, and is particularly intended to remove DME when the raw materials are fed from an MTO unit.
[0033] In one embodiment, the fraction containing DME is recycled to a unit for catalytic decomposition of alcohol located upstream of step a).
[0034] First oligomerization step b) The method of the present invention comprises a first step of oligomerizing at least a portion of the first fraction obtained in step a) to obtain at least one first effluent containing at least 60% by weight of an olefin having 4 or more carbon atoms relative to the total weight of the olefin, wherein the first oligomerization step is carried out in the presence of an oligomerization catalyst.
[0035] Advantageously, the first effluent obtained in the first oligomerization step b) contains, by weight, less than 20%, preferably less than 10%, and preferably less than 5%, of ethylene that was not converted during the first oligomerization step b) with respect to the total weight of the olefins contained in the first effluent.
[0036] Advantageously, at least a portion of the first fraction obtained in step a), i.e., at least 50% by weight, preferably at least 70% by weight, preferably 90% by weight, preferably the entire fraction, is subjected to the first oligomerization step.
[0037] Advantageously, the first oligomerization step b) produces a first effluent containing at least 80% by weight of olefins with 4 or more carbon atoms relative to the total weight of olefins contained in the olefin effluent. In particular, the effluent is rich in olefinic hydrocarbons with 4 to 8 carbon atoms, and also contains olefinic hydrocarbons with 9 or more carbon atoms (C9+). More specifically, the first effluent produced in the first oligomerization step b) preferably contains at least 80% by weight, preferably at least 90% by weight, of olefin compounds with 4 to 8 carbon atoms, and less than 20% by weight, preferably less than 10% by weight, of olefin compounds with 9 or more carbon atoms. Here, the weight percentage is expressed relative to the total weight of olefins contained in the first effluent.
[0038] The oligomerization catalyst used in step b) is any oligomerization catalyst known to those skilled in the art, which may be a homogeneous system, i.e., a catalyst that dissolves in a liquid phase composed of dissolved ethylene and its oligomerization product, or it may be an insoluble heterogeneous system.
[0039] In certain embodiments, the catalyst used in the first oligomerization step b) is a heterogeneous catalyst. The heterogeneous catalyst advantageously comprises at least one group VIII element and at least one porous refractory oxide support, preferably selected individually or as a mixture from alumina, silica, silica-alumina, zirconia, titanium oxide, magnesia, and clay. The group VIII element is preferably selected from nickel, cobalt, iron, platinum, and palladium, with nickel being particularly preferred. The heterogeneous catalyst may also include one or more additional elements selected from group VI, IA, and IIA elements. For example, the group VI element is selected from chromium, molybdenum, and tungsten. The group IA element is selected from lithium, sodium, or potassium, and the group IIA element includes magnesium, calcium, and strontium. Preferably, in this particular embodiment, the support is alumina or silica-alumina. The support may be amorphous silica-alumina, in particular, containing 70% to 99.5% by weight of SiO2 and 100% of the remainder being alumina.
[0040] When the first oligomerization step is carried out using a heterogeneous catalyst, this is performed at a temperature of 30°C to 400°C, preferably 50°C to 300°C, an absolute pressure of 0.5 to 10 MPa, preferably 1 to 10 MPa, preferably 1 to 8 MPa, and a weight-time-space velocity (WHSV) of 0.1 to 10 h, defined as the ratio of the total mass flow rate of the raw materials to the total mass of the catalyst. -1 Preferably 0.4 to 5 hours -1 Therefore, it is preferable that it be executed in this manner.
[0041] In one preferred embodiment, the catalyst used in the first oligomerization step b) is a homogeneous oligomerization catalyst.
[0042] Advantageously, the homogeneous catalyst used in the oligomerization step b) 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 individually or as a mixture from the group formed by chlorinated hydrocarbyl aluminum compounds and brominated hydrocarbyl aluminum compounds. Includes.
[0043] The homogeneous catalyst used in step b) of the oligomerization step of the method according to the present invention optionally includes at least one organobrønsted acid, or at least one carboxylic acid anhydride, or at least one phosphine ligand represented by the formula PR1R2R3 (wherein the formula, the R1, R2, and R3 groups are identical or different from each other and optionally bonded to each other).
[0044] The (+II) oxidized nickel compound is preferably a compound that dissolves in a hydrocarbon medium, more specifically in the reactants and reaction medium, in amounts greater than 1 gram per liter, and is preferably a nickel carboxylate represented by the general formula (RCOO)2Ni, where R is a hydrocarbyl group, such as an alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, or alkaryl group with 20 or fewer carbon atoms, preferably a hydrocarbyl residue with 5 to 20 carbon atoms. The R can be substituted with one or more halogen atoms, or one or more hydroxyl groups, ketone groups, nitro groups or cyano groups, or other groups that do not interfere with the reaction. These two types of R can also constitute alkylene residues with 6 to 18 carbon atoms. As the divalent nickel compound, it is advantageous to select from the following divalent nickel salts: octanoate, 2-ethylhexanoate, decanoate, stearate, oleate, salicylate, and hydroxydecanoate, each individually or in mixtures, but the preferred divalent nickel compound is nickel 2-ethylhexanoate.
[0045] The activator is selected individually or as a mixture from the group formed by chlorinated hydrocarbyl aluminum compounds and brominated hydrocarbyl aluminum compounds corresponding to the formula AlRX2 (wherein R is a hydrocarbyl group and X is a halogen selected from chlorine and bromine). The halides of chlorinated hydrocarbyl aluminum are preferably selected from dichloroethylaluminum, dichloroisobutylaluminum, and dibromoethylaluminum. These dihalides of chlorinated hydrocarbyl aluminum can be advantageously concentrated with aluminum trihalides (AlX3), such as aluminum trichloride.
[0046] The organic Brønsted acid compound preferably corresponds to the formula HY (wherein Y is an organic anion, such as a carboxylic acid anion, a sulfonic acid anion, or a phenolic anion). The compound is preferably selected from the group formed by a halocarboxylic acid of the formula RCOOH (wherein R is a halogenated alkyl group, preferably a halogenated alkyl group having a total of 2 to 10 carbon atoms and containing at least one halogen atom at the alpha position relative to the -COOH group). Preferably, the formula CX p H( 3-p Haloacetic acids of the form )-COOH (wherein X is fluorine, chlorine, bromine, or iodine, and p is an integer from 1 to 3) are used. 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.
[0047] The catalyst used in the first oligomerization step b) may also contain at least one carboxylic acid anhydride of formula (RCO)2O (wherein R is a hydrocarbyl group, which may preferably contain one or more halogen atoms). The carboxylic acid anhydride is advantageously 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, each individually or in mixtures. Preferably, the carboxylic acid anhydride is trifluoroacetic acid anhydride.
[0048] Finally, the catalyst used in the first oligomerization step b) may also contain a phosphine ligand represented by the formula PR1R2R3 (wherein the formula, the R1, R2, and R3 groups are identical or different from each other and optionally bonded to each other). The hydrocarbyl groups R1, R2, and R3 of the phosphine ligand PR1R2R3 preferably 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 the group formed by methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, cyclopentyl, cyclohexyl, benzyl, and adamantyl groups.
[0049] The catalyst can be pretreated before contacting it with ethylene. The catalyst composition is pretreated by 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, with stirring under an inert atmosphere such as 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. The resulting solution is then transferred to an oligomerization reactor under an inert atmosphere.
[0050] This catalyst pretreatment allows for increased catalytic activity in the oligomerization of ethylene.
[0051] The catalyst present in the unit performing oligomerization step b) is in liquid form. Depending on the chemical composition of the catalyst, it is necessary to control the weight ratio of each component during catalyst synthesis. The molar ratio of the hydrocarbyl aluminum halide to the nickel compound, expressed as an Al / Ni ratio, is 2 / 1 to 50 / 1, preferably 2 / 1 to 20 / 1.
[0052] The molar ratio of Brønsted acid to the nickel compound is 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 preferably 0.001 / 1 to 1 / 1, more preferably 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.
[0053] In one embodiment, the homogeneous catalyst is the catalyst described in International Publication No. 2017017087.
[0054] The first oligomerization step b), carried out by a homogeneous catalyst, is advantageously carried out continuously. That is, the catalyst solution is injected into the unit carrying out the oligomerization step, and ethylene is continuously injected therein. The apparatus carrying out the oligomerization step of ethylene by a homogeneous catalyst comprises one or more fully agitated reactors connected in series, and at least a portion of the effluent from the reactors is recycled into the reactors. This recycled liquid is preferably cooled.
[0055] The first oligomerization step b) is advantageously carried out in a reactor having one or more reaction stages in series, wherein the ethylene-based raw materials and / or pre-treated catalyst composition are introduced continuously into the first stage, or into the first stage and any one of the other stages.
[0056] The operating conditions for the reactor carrying out the oligomerization process using a homogeneous catalyst 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.
[0057] At the outlet of the first oligomerization step b), the homogeneous catalyst system is found as a mixture of the effluent produced during step b) and unreacted ethylene.
[0058] Advantageously, the olefin effluent produced during the first oligomerization step b) is subjected to at least one step of processing / separating the homogeneous catalytic system of the effluent before being sent to the second oligomerization step c).
[0059] The process of processing / separating a homogeneous catalyst system is understood to mean the process of deactivating the catalyst system and separating it from the homogeneous reaction medium, particularly from the olefin effluent resulting from the first oligomerization process b).
[0060] In one embodiment, the first effluent from the first oligomerization step b) is subjected to a fractionation step to obtain at least one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 4 to 8 carbon atoms, which is sent to the second oligomerization step c), and a fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 9 or more carbon atoms (C9+), which is sent to the hydrogenation step d). This embodiment makes it possible to limit the generation of heavy products (excluding the kerosene fraction) and thus increase the yield of the kerosene fraction. This also makes it possible to use a small reactor in the second oligomerization step c).
[0061] In one embodiment, the first effluent obtained in the first oligomerization step b) is subjected to a fractionation step to obtain a fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a processed product having 2 or fewer carbon atoms, and the fraction is preferably removed.
[0062] An example of the first oligomerization step b) is the DimEne-B® process sold by Axens.
[0063] Another example of the first oligomerization step b) is the Dimersol-E® process sold by Axens.
[0064] Second oligomerization step c) The method according to the present invention includes at least, - A portion of the first outflow from process b), - Part of the second stroke from process a) The second step c) comprises oligomerizing the olefin to obtain a second effluent containing at least 85% by weight, preferably at least 90% by weight, preferably at least 95% by weight, of olefins having 7 or more carbon atoms relative to the total weight of the olefin, wherein the second oligomerization step is carried out in the presence of an amorphous or zeolite-based heterogeneous catalyst.
[0065] According to one embodiment, the catalyst used in the second oligomerization step c) is an amorphous catalyst, preferably comprising an amorphous inorganic material selected from silica-alumina and siliceous alumina.
[0066] In a particularly specific embodiment in which silica-alumina is used as a catalyst in the second oligomerization step c), oligomerization with silica-alumina, especially oligomerization of at least a portion of the first effluent from step b) and a portion of the second fraction from step a), can be carried out with better control over the reactivity of the olefin. In particular, it is possible to keep the conversion rate per pass low and optimize the selectivity for desired olefins with 7 or more carbon atoms, especially 10 to 12, very favorably compared to oligomerization using other catalysts such as zeolites. In addition, it was found that in the presence of silica-alumina, the amount of coke produced was less and the production rate was slower compared to the presence of zeolites. Therefore, silica-alumina requires less frequent regeneration than zeolites.
[0067] According to one embodiment, the catalyst used in the second oligomerization step c) is preferably a zeolite-based catalyst comprising a zeolite having pore openings containing at least 10 or 12 oxygen atoms (10MR or 12MR), and is preferably selected from aluminosilicate-type zeolites having an overall Si / Al ratio greater than 10.
[0068] According to one embodiment, the zeolite catalyst comprises zeolites selected individually or as a mixture from among zeolites having the structural types MFI, MTW, MOR, TON, MEL, MFS, or MTT.
[0069] According to another embodiment, the zeolite catalyst used in the second oligomerization step c) comprises zeolites selected individually or as mixtures from each of the zeolites 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, preferably zeolites selected individually or as mixtures from each of the zeolites ZSM-5, NU-10, and ZBM-30, most preferably the zeolite being ZBM-30, and even more preferably the zeolite being ZBM-30 synthesized in the presence of a triethylenetetramine structuring agent.
[0070] The zeolite used as a catalyst in step c) of the method according to the present invention is advantageous to be subjected to several post-treatments known to those skilled in the art, such as modification by dealuminulation or desilicaration according to any dealuminulation method, external surface deactivation method or desilicaration method known to those skilled in the art, in order to improve its activity and / or stability.
[0071] The catalyst used in step c) of the method according to the present invention preferably also includes at least one oxide matrix, also called a binder. According to the present invention, the matrix means an amorphous matrix or a matrix with low crystallinity.
[0072] The matrix is preferably selected from elements of the group formed by clay (e.g., natural clay such as kaolin or bentonite), magnesia, alumina, silica, silica-alumina, aluminate (aluminate salt), 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.
[0073] The catalyst used in step c) of the method according to the present invention is preferably molded into the form of particles having various external shapes and sizes. They are preferably used in the form of cylindrical or multi-lobed extruded articles (e.g., bi-lobed, tri-lobed, multi-lobed extruded articles, etc.) and in a linear or twisted shape, but can also be manufactured and used in the form of crushed powder, tablets, rings, beads, wheels, or spherical shapes. Preferably, the catalyst is in the form of extruded products having a size of 1 to 10 mm.
[0074] The second oligomerization step c) is advantageously carried out in at least one fixed-bed reactor.
[0075] The second oligomerization step c) of the method according to the present invention is performed at a temperature of 20°C to 500°C, preferably 100°C to 350°C, preferably 100°C to 300°C, at a pressure of 0.1 to 10 MPa, preferably 2 to 8 MPa, preferably 3 to 7 MPa, and preferably for 0.1 to 0.5 hours. -1 Preferably 0.2 to 0.3 hours -1 It will be implemented favorably under the HSV.
[0076] According to the present invention, HSV (i.e., space velocity per hour) is defined in particular by the ratio of the volumetric flow rate of fresh olefin-based raw materials at 15°C and 1 atmosphere to the volume of the oligomerization catalyst during operation (also known as use).
[0077] The second effluent generated during the second oligomerization step c) is advantageously a effluent containing less than 20% by weight, preferably less than 10% by weight, of C4 olefins that were not converted during the second oligomerization step c), where the weight percentage is expressed relative to the total weight of the olefins contained in the second effluent.
[0078] The second effluent produced during the second oligomerization step c) is advantageous to contain less than 20% by weight, preferably less than 10% by weight, of C4-C8 olefin compounds, where the weight percentage is expressed relative to the total weight of the olefins contained in the second effluent.
[0079] An example of the second oligomerization step c) is the Polynaphtha® process sold by Axens.
[0080] The second effluent obtained in heterogeneous oligomerization step c) is then sent to hydrogenation step d). Preferably, this second effluent can be fractionated into at least one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of compounds with 3 to 4 carbon atoms, which is advantageously purged, and a fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of compounds with 5 or more carbon atoms (C5+), which is sent to hydrogenation step d).
[0081] In one embodiment, the second outflow from step c) is at least - One fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 3 to 8 carbon atoms. - One fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of an olefin having 9 or more carbon atoms (C9+). To obtain the desired result, it is subjected to a fractionation process.
[0082] Advantageously, one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of an olefin having 9 or more carbon atoms (C9+) is sent to hydrogenation step d).
[0083] Advantageously, at least a portion of one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 3 to 8 carbon atoms is recycled to the inlet of the second oligomerization step c).
[0084] Advantageously, a first portion of the fraction containing a compound having 3 to 8 carbon atoms in an amount of at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, is recycled to the inlet of a second oligomerization step c) (referred to as c1 in this embodiment), and the second portion is sent to another heterogeneous oligomerization step c2) to obtain effluent from the other heterogeneous oligomerization step.
[0085] Another heterogeneous oligomerization step c2) is advantageously performed using the same catalyst as step c1), at a temperature of 50°C to 500°C, preferably 100°C to 350°C, preferably 130°C to 300°C, at a pressure of 2.0 to 12 MPa, preferably 2 to 10 MPa, preferably 4 to 7 MPa, and preferably for 0.1 to 1.0 hours. -1 Preferably 0.3 to 0.6 hours -1 It will be implemented in HSV.
[0086] In one embodiment, a first portion of the effluent from another heterogeneous oligomerization step c2) is recirculated to the inlet of the latter, and a second portion is sent to the hydrogenation step d).
[0087] Hydrogenation process d) The method according to the present invention includes step d) hydrogenating the second effluent from step c) to obtain a third effluent containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight of paraffin.
[0088] In one embodiment, the hydrogenation step d) is also supplied with the C9+ cut (fraction) obtained by fractional distillation downstream of the first oligomerization step b).
[0089] Advantageously, the hydrogenation step d) is carried out by contacting a hydrogen-rich gas with at least one group VIII metal, preferably selected individually or as a mixture from palladium and nickel, and a support, preferably selected from alumina, silica, or silica-alumina.
[0090] The catalyst used in the hydrogenation step preferably comprises 0.1 wt% to 10 wt% of palladium, and / or preferably 1 wt% to 60 wt% of nickel, relative to the total weight of the catalyst.
[0091] The hydrogenation step is advantageously carried out at a temperature of 100°C to 250°C, a pressure of 2 to 5 MPa, and a weight hourly space velocity of 0.05 to 8 h -1 at the inlet of the reactor. The hydrogenation performance is confirmed by measuring the bromine number, and when it is desired to saturate all unsaturated compounds present in the fraction to be hydrogenated, the bromine number is preferably at most 5 gBr / 100g.
[0092] Fractionation step e) The process according to the present invention comprises step e) of fractionating the third effluent from step d) to obtain at least one aviation fuel fraction.
[0093] The fractionation step e) is advantageously carried out in at least one distillation column such that the effluent is separated into at least the following three fractions: - naphtha fraction, - aviation fuel fraction, - gas oil fraction. In one embodiment, a gas fraction is also obtained, which is preferably purged.
[0094] The "naphtha" fraction means a fraction comprising hydrocarbon compounds having a boiling point between normal temperature and 220°C.
[0095] The "aviation fuel" fraction means a fraction comprising hydrocarbon compounds having a boiling point of 130°C to 300°C. This fraction may also be referred to as a "kerosene" fraction.
[0096] The "gas oil" fraction means a fraction comprising hydrocarbon compounds having a boiling point of 220°C to 360°C.
[0097] (List of drawings) Figure 1 The raw material 10 is sent to fractionation step a) to produce a first fraction 11 containing at least 85% of the ethylene contained in the raw material 10, a second fraction 12 containing at least 90% by weight of compounds with three or more carbon atoms, a heavy fraction 13 containing at least 90% by weight of benzene and compounds heavier than benzene, and a fraction 18 containing at least 90% by weight of the DME present in the raw material 10. Fraction 11 is sent to the first oligomerization step b) to produce an effluent containing at least 60% by weight of olefins with four or more carbon atoms relative to the total weight of olefins contained in the effluent, and the effluent is fractionally distilled to obtain a fraction 14 containing at least 90% by weight of compounds with 4 to 8 carbon atoms, a fraction 15 containing at least 90% by weight of compounds with two or fewer carbon atoms, and a fraction 16 containing at least 90% by weight of compounds with nine or more carbon atoms. Fractions 14 and 12 are mixed to form stream 20, which is sent to the second heterogeneous oligomerization step c) to produce effluent 21 containing at least 85% by weight of olefins with 7 or more carbon atoms relative to the total weight of olefins contained in the effluent. Effluent 21 and fraction 16 are mixed to form stream 22, which is sent to the olefin hydrogenation step d) to produce effluent 24 containing at least 90% by weight of paraffin and purge 23 containing unreacted hydrogen and the lightest gas. Effluent 24 is sent to the fractionation step e) to produce gas purge 25, naphtha fraction 26, aviation fuel fraction 27, and diesel fraction 28.
[0098] Figure 2 The raw material 10 is sent to fractionation step a) to produce a first fraction 11 containing at least 85% of the ethylene contained in the raw material 10, a second fraction 12 containing at least 90% by weight of compounds with three or more carbon atoms, a heavy fraction 13 containing at least 90% by weight of benzene and compounds heavier than benzene, and a fraction 18 containing at least 90% by weight of the DME present in the raw material 10. Fraction 11 is sent to the first oligomerization step b) to produce an effluent containing at least 60% by weight of olefins with four or more carbon atoms relative to the total weight of olefins contained in the effluent, and the effluent is fractionated to obtain a fraction 14 containing at least 90% by weight of compounds with 4 to 8 carbon atoms, a fraction 15 containing at least 90% by weight of compounds with two or fewer carbon atoms, and a fraction 16 containing at least 90% by weight of compounds with nine or more carbon atoms. Fractions 14 and 12 are mixed to form stream 20, which is sent to the first step c1) of the second heterogeneous oligomerization. This stream 20 is then produced in which at least 90% by weight of olefins with 7 or more carbon atoms is generated relative to the total weight of olefins contained in the effluent. This is then fractionated to obtain fraction 30 containing at least 90% by weight of compounds with 3 to 8 carbon atoms and fraction 31 containing at least 90% by weight of olefins with 9 or more carbon atoms. The first portion of fraction 30 is recirculated to the inlet of step c1), the second portion 32 is sent to another step c2) of heterogeneous oligomerization to produce an effluent, the first portion of which is recirculated to the inlet of step c2), and the other portion 33 is mixed with fraction 31 to form stream 21 containing at least 85% by weight of olefins with 7 or more carbon atoms relative to the total weight of olefins contained in the stream. This stream 21 is then mixed with fraction 16 to form stream 22, which is sent together with fraction 13 to olefin hydrogenation step d) to produce an effluent 24 containing at least 90% by weight of paraffin and a purge 23 containing unreacted hydrogen and the lightest gas. The effluent 24 is sent to fractionation step e) to produce a gas purge 25, naphtha fraction 26, aviation fuel fraction 27 and diesel fraction 28.
[0099] Examples Example 1: Method for producing aviation fuel according to one embodiment of the present invention: Due to the partial overlap in boiling points of compounds present in the kerosene fraction and the diesel fuel fraction, and for the sake of simplification, 290°C is selected as the boundary point between kerosene and diesel fuel in this embodiment.
[0100] Therefore, in this embodiment, "fraction 130-290" refers to all hydrocarbon compounds with boiling points between 130°C and 290°C, and this fraction is the kerosene fraction. "Fraction 290-360" refers to all hydrocarbon compounds with boiling points between 290°C and 360°C, and this fraction is the diesel fraction.
[0101] The stream numbers are shown in Figures 1 and 2.
[0102] The raw material 10 under consideration is an olefinic fraction obtained from the decomposition of methanol and having the following composition (values are weight percentages):
[0103] [Table 1]
[0104] Fractionation process a) This consists of a series of distillation columns.
[0105] The first column, operated at 2.0 MPa, will be able to recover most of the compounds containing three or fewer carbon atoms at the top of the column, and most of the compounds containing four or more carbon atoms, as well as dimethyl ether, at the bottom of the column.
[0106] A second column, operated at 3.0 MPa, fractionates the bottom products from the first column, enabling the recovery of most compounds containing two or fewer carbon atoms at the top and most compounds containing three or more carbon atoms at the bottom.
[0107] A third column, operated at 1.2 MPa, fractionates the bottom products from the first column, allowing for the recovery of most of the dimethyl ether at the top and most of the compounds containing four or more carbon atoms at the bottom.
[0108] The top product 11 from the second tower is sent to the first oligomerization step b).
[0109] The bottom product from the second column is mixed with the bottom product from the third column (stream 12) and sent to the second heterogeneous oligomerization step c).
[0110] [Table 2]
[0111] Step b) - First oligomerization step The reactor in step b) is operated at 4.5 MPa and 50°C. The catalyst is a homogeneous nickel-based catalyst sold by Axens under the name LC1251. The co-catalyst is dichloroethylaluminum (EADC), which is used as an n-hexane solution. The molar ratio of the catalyst to the co-catalyst is adjusted so that the Al / Ni molar ratio is 15.
[0112] The catalyst concentration is adjusted so that a 97.5% ethylene conversion rate is obtained in the reactor.
[0113] The effluent from the oligomerization reactor is fractionated by the following two series of distillation columns: The first column, operated at -2.8 MPa, allows for the recovery of most compounds containing two or fewer carbon atoms at the top of the column and most compounds containing three or more carbon atoms at the bottom of the column. A second column, operated at -0.8 MPa, fractionally distills the bottom products from the first column, allowing for the recovery of most compounds containing 3 to 8 carbon atoms at the top and most compounds containing 9 or more carbon atoms at the bottom.
[0114] The top product 14 from this second column constitutes the effluent from step b) and is sent to the second heterogeneous oligomerization step c). The bottom product 16 from the second column is itself sent to the hydrogenation step d).
[0115] [Table 3]
[0116] Second heterogeneous oligomerization step c) The raw material 20 for the heterogeneous oligomerization unit is a mixture of the effluent 12 from fractionation step a) and the effluent 14 from the first oligomerization step b).
[0117] [Table 4]
[0118] Heterogeneous oligomerization is carried out in two steps c1) and c2).
[0119] Process c1) The first step of heterogeneous oligomerization is carried out in three reactors connected in series, with an intermediate heat exchanger between each reactor to cool the waste before it enters the next reactor.
[0120] The first step of heterogeneous oligomerization is carried out in the presence of the silica-alumina catalyst IP811, sold by Axens. The operating conditions for step c1) are a temperature of 110°C, a reactor inlet pressure of 4.5 MPa, and a total space velocity of 0.2 h in the reactor. -1 (Excluding recirculation)
[0121] The reaction effluent obtained as a result of the first step of this heterogeneous oligomerization is separated into the following two fractions by distillation.
[0122] - A fraction 30 consisting mainly of olefins containing 3 to 8 carbon atoms, 95% of which is recycled to the first step c1) of heterogeneous oligomerization (this corresponds to the weight ratio of fractions containing 8 or fewer carbon atoms (C8-) to olefin hydrocarbon feedstock being 2.4 at the inlet of the first step c1)). The fraction 31, which is -C9+, is sent to the hydrogenation step d).
[0123] Of the fraction 30, which mainly consists of olefins having 3 to 8 carbon atoms, 5% by weight is not recycled to the first step c1) of heterogeneous oligomerization, and 32 is sent to the second step c2) of heterogeneous oligomerization.
[0124] [Table 5]
[0125] Process c2) The second step of heterogeneous oligomerization is carried out in two reactors connected in series, with an intermediate heat exchanger between each reactor to cool the effluent before it enters the next reactor.
[0126] The second step of heterogeneous oligomerization is carried out in the presence of the silica-alumina catalyst IP811, sold by Axens. The operating conditions for step c2 are a temperature of 150°C, a reactor inlet pressure of 7.0 MPa, and a total space velocity of 0.5 h in the reactor. -1 (Excluding recirculation)
[0127] Fifty percent by weight of the reaction effluent obtained at the end of the second step of heterogeneous oligomerization is recycled to the inlet of this step. The remaining 50% 33 of the reaction distillate is mixed with a fraction 31 of C9+ obtained by distillation of the effluent from the first step c1) of heterogeneous oligomerization. The resulting mixture 21 is sent to the olefin hydrogenation step d).
[0128] [Table 6]
[0129] Olefin hydrogenation process d) The raw material 22 that enters the olefin hydrogenation process is -The bottom product 16 of the second column downstream of the first oligomerization step b), -The fraction 31 of C9+ obtained by distillation downstream of the first step c1) of heterogeneous oligomerization, - Non-recirculating portion 33 of the effluent from the second step c2) of heterogeneous oligomerization It consists of.
[0130] [Table 7]
[0131] The olefin hydrogenation step d) is carried out using the nickel-based catalyst LD746 sold by Axens, in which the majority of the olefin is hydrogenated to produce paraffin while minimizing the production of light hydrocarbon molecules. This step is carried out at a temperature of 160°C and a pressure of 2.5 MPa at the reactor inlet. The space rate per hour in the reaction compartment is 3h -1 Therefore, the H2 / HC (hydrocarbon) ratio is equal to 100.
[0132] The olefin content of the effluent 24 from this hydrogenation process is 1% by weight.
[0133] Fractionation process e) The effluent 24 discharged from hydrogenation step d) is sent to fractionation step e) which is carried out in a series of three fractionation columns: The first column, operated at -0.7 MPa, has a top product 25 that mainly consists of compounds containing five or fewer carbon atoms. -The second column, fed from the bottom of the first column and operated at 0.15 MPa, has top products 26 mainly consisting of compounds containing 5 to 8 carbon atoms. -The third column is fed from the bottom of the second column and operated at 0.05 MPa. The top product 27 of this column is 130-290 fractions, and the bottom product 28 is 290-360 fractions.
[0134] [Table 8]
[0135] According to this embodiment, the production yield of 130-290 fractions (kerosene fraction) per ton / hour of raw material is 900 kg / h. The combined production yield of 130-290 fractions and 290-360 fractions (kerosene fraction + diesel fraction) is 925 kg / h. The present invention makes it possible to maximize the production yield of the kerosene fraction compared to processes in which ethylene is not converted or is hardly converted. In fact, such production of the kerosene fraction is impossible without the conversion of ethylene, which alone accounts for more than 10% of the raw material.
Claims
1. A method for producing aviation fuel from raw materials containing olefins, wherein the raw materials contain the following components: - The olefin content is 50% by weight or more, preferably 65% by weight or more, preferably 80% by weight or more. - The ethylene content is less than 80% by weight, preferably less than 65% by weight, and preferably less than 50% by weight, relative to the total weight of the olefin contained in the raw material. The above method includes the following steps: a) The raw materials are fractionated, at least - A first fraction containing at least 85% by weight, preferably at least 90% by weight, preferably at least 95% by weight of the ethylene present in the raw material introduced in step a), - A second fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having at least three carbon atoms. The process of obtaining b) A first step of oligomerizing at least a portion of the first fraction obtained in step a), the first step of obtaining a first effluent containing an olefin having four or more carbon atoms relative to the total weight of the olefin contained therein, The first oligomerization step is carried out in the presence of an oligomerization catalyst. c) At least, - A portion of the first outflow from process b), - A portion of the second stroke from step a) A second oligomerization step, wherein the second oligomerization step is performed in the presence of a heterogeneous amorphous catalyst or a heterogeneous zeolite catalyst, and the second oligomerization step is performed in the presence of a heterogeneous amorphous catalyst or a heterogeneous zeolite catalyst. d) A step of hydrogenating the second effluent from step c) to obtain a third effluent containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight of paraffin. e) A step of fractionally distilling the third spillage from step d) to obtain at least one aviation fuel fraction.
2. The method according to claim 1, wherein the raw material contains at least 50% by weight, preferably at least 65% by weight, and preferably at least 80% by weight, of an olefin having 2 to 6 carbon atoms, relative to the total weight of the raw material.
3. The method according to any one of the preceding claims, wherein the raw material is derived from a unit for catalytic decomposition of alcohol.
4. The method according to any one of the preceding claims, wherein a heavy fraction is additionally obtained in step a), and this heavy fraction contains at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of benzene and compounds heavier than benzene.
5. The method according to claim 4, wherein all or part of the heavy fraction is sent to the hydrogenation step d).
6. The method according to any one of the preceding claims, wherein the oligomerization catalyst used in the first oligomerization step b) is a homogeneous catalyst.
7. The homogeneous catalyst is - (+II) oxidation state of at least one precursor of nickel, - and at least one activator selected individually or as a mixture from the group formed by chlorinated hydrocarbyl aluminum compounds and brominated hydrocarbyl aluminum compounds. The method according to claim 6, including the method described in claim 6.
8. The method according to any one of the preceding claims, wherein the first effluent from the first oligomerization step b) contains ethylene in an amount of less than 20% by weight, preferably less than 10% by weight, and preferably less than 5% by weight, relative to the total weight of the olefin contained in the first effluent.
9. The method according to any one of the preceding claims, wherein the first effluent from the first oligomerization step b) is subjected to a fractionation step to obtain at least one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 4 to 8 carbon atoms, which is sent to the second oligomerization step c), and one fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 9 or more carbon atoms, which is sent to the hydrogenation step d).
10. The method according to any one of the preceding claims, wherein the second oligomerization step c) is carried out in the presence of an amorphous heterogeneous catalyst, or a heterogeneous catalyst comprising at least one zeolite having pore openings containing at least 10 or 12 oxygen atoms.
11. The second outflow from step c) is at least - A fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 3 to 8 carbon atoms. - One fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, an olefin having 9 or more carbon atoms. The method according to any one of the preceding claims, which is subjected to a fractional distillation step in order to obtain.
12. The method according to claim 11, wherein the fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having nine or more carbon atoms is sent to the hydrogenation step d).
13. The method according to either claim 11 or claim 12, wherein at least a portion of the fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 3 to 8 carbon atoms is recycled to the inlet of the second oligomerization step c).
14. The method according to any one of claims 11 and 12, wherein a first portion of the fraction containing at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, of a compound having 3 to 8 carbon atoms is recycled to the inlet of the second oligomerization step c), and the second portion is sent to another heterogeneous oligomerization step c2) to obtain effluent from the other heterogeneous oligomerization step.
15. The method according to claim 14, wherein the first portion of the effluent from the other heterogeneous oligomerization step c2) is recirculated to the inlet of the latter (the other heterogeneous oligomerization step), and the second portion is sent to the hydrogenation step d).