Method for producing middle distillates by co-processing mineral feedstocks with renewable feedstocks, comprising series of catalysts, including beta zeolite-based catalysts

Abstract

The invention relates to a process for producing a middle distillate from at least one fossil hydrocarbon feedstock mixed with at least one renewable feedstock, said process comprising a step of hydrotreating said feedstock in the presence of hydrogen and at least one hydrotreating catalyst and a step of hydrocracking the hydrotreated feedstock, the hydrocracking step comprises at least one step of contacting the hydrotreated feedstock in a first catalytic zone with at least one first catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprises at least one zeolite having at least one series of channels whose openings are defined by a ring of 12 oxygen atoms (12MR) and at least one binder, all the effluent from step a) is then brought into contact with a second catalyst in a second catalytic zone without an intermediate separation step between the first catalytic zone and the second catalytic zone, the second catalyst comprises at least one metal from group VIB of the periodic table and / or at least one metal from group VIII of the periodic table and a support comprising at least one zeolite of the BEA framework type and at least one binder.

Description

Field of the Invention

[0001] The present invention relates to a process for producing middle distillates, which comprises a hydrotreating step and a hydrocracking step, the hydrocracking step being characterized in that it uses two catalysts in two separate hydrocracking zones operating in series.

[0002] The process converts a set of hydrocarbon feedstocks into target products (products of interest) (naphtha, jet fuel, diesel). These hydrocarbon feedstocks contain, for example, aromatic and / or olefinic and / or naphthenic and / or paraffinic compounds, including "fossil" feedstocks such as straight run distillates from crude oil or vacuum distillate (VD) fractions or vacuum gas oil (VGO) fractions from conversion units such as FCC, coking, H - oil or visbreaking units, feedstocks from the Fischer - Tropsch process, feedstocks resulting from the conversion of tar sands and shale oil, which are mixed with at least one renewable feedstock selected from vegetable oils, algal oils, edible oils and animal fats, which may be fresh or used, either alone or as a mixture, and feedstocks obtained from the reprocessing of biomass / plastic / tyre / and household waste, either alone or as mixtures. These feedstocks may contain metals and / or nitrogen and / or oxygen and / or sulfur.

[0003] The aim of the process according to the invention is essentially to produce middle distillate fractions which comprise a kerosene fraction having an initial boiling point and a final boiling point in the range extending from 130 °C to 300 °C and a gas oil fraction having an initial boiling point and a final boiling point in the range extending from 220 °C to 390 °C.

[0004] In particular, the present invention relates to a process for producing middle distillates from hydrocarbon feedstocks of preferably vacuum distillate type, said hydrocarbon feedstocks being mixed with at least one renewable feedstock selected from vegetable oils, algal oils, edible oils and animal fats, which may be fresh or used, either alone or as a mixture, and feedstocks obtained from the reprocessing of biomass / plastic / tyre / and household waste, either alone or as mixtures, said process comprising a hydrotreating step and a hydrocracking step. The hydrocracking step is carried out in the presence of a sequence of two specific catalysts used in two separate catalytic zones, all the effluents from the first catalytic zone being sent directly into the second catalytic zone to contact the second catalyst, without intermediate separation of the gas phase between the two catalytic zones of the second hydrocracking step.

[0005] In particular, the first catalyst used in the first catalytic zone of the hydrocracking step comprises at least one metal from Group VI of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support comprising at least one large pore zeolite (12MR), such that the hydrocarbon feedstock can be converted quite considerably upstream of the second catalyst.

[0006] According to the present invention, the second catalyst used in the second catalytic zone of the hydrocracking step comprises at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support comprising at least one zeolite of the BEA structure type. Prior art

[0007] A process for producing middle distillates comprising a hydrocracking step of a heavy petroleum fraction is an inescapable process in refining at present, and said process makes it possible to produce lighter fractions, such as gasoline, jet engine fuel and gas oil, from residual and hardly upgradable heavy feedstocks. Refiners seek such a process to adapt their production to demand conditions. Certain hydrocracking processes also make it possible to obtain highly purified residues, which can provide an excellent basis for the production of oils. Compared with fluid catalytic cracking (FCC), the advantage of catalytic hydrocracking lies in providing middle distillate oils of very good quality. On the contrary, the gasoline produced has a much lower octane number than the gasoline obtained by catalytic cracking.

[0008] The flexibility of the process stems from three main elements, which are: the operating conditions used, the type of catalyst used and the fact that the hydrocracking of the hydrocarbon feedstock can be carried out in one step or in two steps. It is thus suitable for treating and converting any type of hydrocarbon feedstock, provided that the latter is compatible with being injected in liquid form into the catalytic reactor. In particular, it is capable of using alone or in admixture feedstocks from crude oil distillation, but can also use, for example, vegetable oils, animal fats.

[0009] It can be carried out in one step in the presence of a single catalyst in one or more reactors in series, said single catalyst not only hydrocracking the hydrocarbon feedstock into products with lower boiling points, but also converting the residual organic compounds containing sulfur and nitrogen into hydrogen sulfide and ammonia, respectively.

[0010] The hydrocracking catalyst used in the process for producing middle distillate oils is called bifunctional, i.e., combining an acid function with a hydrogenation-dehydrogenation function. The acid function is provided by an oxide having a surface area generally in the range of 150 to 1000 m 2 ·g -1 such as halogenated (especially chlorinated or fluorinated) alumina, a combination of boron oxide and alumina, amorphous silica-alumina and zeolites. The hydrogenation-dehydrogenation function is provided by one or more metals from Group VIB of the Periodic Table, or by a combination of at least one metal from Group VIB of the Periodic Table and at least one metal from Group VIII.

[0011] The balance between these two functionalities is one of the parameters controlling the activity and selectivity of said catalyst. Weak acid functionalities and strong hydrodehydrogenation functionalities provide a catalyst with not very high activity, which usually operates at elevated temperatures (greater than or equal to 390 - 400 °C) and at low feed space velocity (HSV expressed as the volume of feedstock to be treated per unit volume of catalyst and per hour is usually less than or equal to 2 h -1 ), but which has very good selectivity for middle distillates (jet engine fuel and gas oil). On the contrary, strong acid functionalities and weak hydrodehydrogenation functionalities provide a catalyst with high activity, but with poor selectivity for middle distillates.

[0012] One type of conventional hydrocracking catalyst is based on medium - acidic amorphous oxides, such as silica - alumina for example. These systems are used to produce good - quality middle distillates, as well as possibly oil bases. The drawback of these catalysts based on amorphous supports is their low activity.

[0013] Catalysts containing, for example, Y zeolite or catalysts containing, for example, β zeolite themselves exhibit higher catalytic activity than silica - alumina, but generally exhibit lower selectivity for middle distillates (jet engine fuel and gas oil).

[0014] Generally, hydrocracking catalysts containing only Y zeolite do not allow good cold properties (in terms of the cloud point, pour point, cold filter plugging point of said fraction) of the gas oil fraction to be obtained, but also do not allow good cold properties (in terms of the crystal appearance point) of the kerosene fraction to be obtained. These values are highly correlated with the straight - chain paraffins with higher boiling points present in these fractions. To meet the fuel specifications in terms of cold properties, this may require the refinery to lower the final boiling point of the fraction (to reduce the content of high - boiling paraffins), the direct effect of which is to reduce their yield, in favor of heavy fractions that are not upgradeable or more difficult to upgrade.

[0015] The prior art mentions numerous studies on improving the selectivity of zeolite catalysts for middle distillates in hydrocracking processes. The latter consist of a hydrodehydrogenation phase based on transition metals, which is usually deposited on a support containing zeolite (usually USY zeolite). The hydrodehydrogenation phase is usually in the form of transition metal sulfides.

[0016] For example, studies involving the use of catalysts comprising Y zeolites modified, for example, by dealumination with steam or acid attack, the use of composite catalysts, or the use of small crystal Y zeolites can be mentioned. Other patent applications, such as patent US7585405, describe the use of catalysts comprising mixtures of zeolites such as beta zeolite and USY zeolite for improving the performance of hydrocracking catalysts. In order to maximize the yield of middle distillates, it is necessary to finely adjust the USY / beta mass ratio, and here it is also necessary to precisely select USY zeolites having lattice parameters specifically of 24.37 to No mention is made of the variation in the relative yields of the gas oil and kerosene fractions.

[0017] In contrast, patent application WO08085517 provides for the use of a single zeolite source for formulating catalysts. The introduced beta zeolite has an SAR of less than 30 and teaches that it is preferably not subjected to much post-treatment after removing the structuring agent used in the manufacture. Compared with other catalytic formulations of beta zeolites that undergo various heat treatments (steam treatment) in the presence of steam, a gain in the middle distillate yield of about 2 to 3 points is shown, without indicating the corresponding yields of the gas oil or kerosene fractions.

[0018] Generally, when changing the catalyst or operating conditions of a hydrocracking process, various technical solutions have been proposed, which cause an improvement in the yield of middle distillates, but this increase is usually borne by an increase in the gas oil fraction yield, and the gain in the kerosene fraction remains low or even zero.

[0019] As described in patent US7749373, an alternative can include using a first hydrocracking catalyst containing acid functionality, followed by a second catalyst containing beta zeolite, without any intermediate separation of the gas or liquid products between the two catalytic zones. Preferably, in this case, the second catalyst comprises beta zeolite having an SAR greater than 25 and very preferably greater than 250. The examples confirm that after prior hydrotreating of a feedstock of the vacuum gas oil type, compared with a charge using only a catalyst supported on Y zeolite, first 75% by volume of which contains 10% by weight in its support having an SAR equal to 30 and having an equal The sequence of the catalyst of Y zeolite with its unit cell parameters and subsequently the catalyst containing 3% beta zeolite (the beta zeolite having a SAR of 300) in its support allows the operating temperature to be reduced by 4 °C to achieve a target conversion rate of 87%. Subsequently, a gain of 3.5 wt% was also observed in the yield of middle distillates, which was entirely borne by the increase in the yield of the gasoil fraction, while the yield of kerosene remained unchanged (and its low-temperature properties also remained unchanged). In other words, the method using the said catalyst sequence allows the yield of the gasoil fraction to be improved and the low-temperature properties of the said gasoil fraction in terms of pour point to be improved, but the method cannot bring any improvement to the yield of the obtained kerosene fraction. This also applies to the low-temperature properties of the kerosene fraction, which are the same as those obtained by the method using only the catalyst containing Y zeolite with the same amount of the catalyst used.

[0020] In order to particularly maximize the production of middle distillates and reduce the carbon footprint of the refining process, in addition to fossil raw materials, it can also be shown that it is advantageous to use renewable raw materials, which can lead to a reduction in the carbon footprint. Among renewable raw materials, for example, vegetable oils, animal fats or used cooking oils can be mentioned, which generally produce long straight-chain alkanes after hydrotreating, which mainly contain nC 15 to nC 18 hydrocarbons. However, these straight-chain alkanes impart poor low-temperature properties to the gasoil, which means that these compounds need to be isomerized to achieve the required fuel specifications. Another advantageous solution is also to convert these straight-chain alkanes by selective hydrocracking in order to directly incorporate them into the kerosene fraction. This also allows renewable carbon to be introduced into this fossil fraction. In particular, the production of bio-kerosene, also known as "SAF" ("sustainable aviation fuel"), is sought to decarbonize the aviation sector (civil and military).

[0021] Thus, in the context of reducing greenhouse gas emissions, refineries must increase the proportion of components of biological origin in fuels. The objective of public authorities is to promote the use of biofuels in transport, not only in road transport (diesel and gasoline engines), but also in air transport. For example, the Roadmap of Ancre (the French National Alliance for the Coordination of Energy Research), published in June 2018, evaluated the potential of the French aviation biofuel production sector, taking into account the maturity and development time of these industrial sectors. Thus, the subsequent deployment trajectory reflects France's ambition to incorporate 5% of aviation biofuels into France by 2030. In addition, the French National Low Carbon Strategy (SNBC), revised in 2018, defines the long-term guidance for air transport until 2050, with the objective of replacing 50% of the fuels of traditional fossil origin with biofuels. Thus, the production of biofuels has been promoted in recent years and will continue to be strongly enhanced in the coming years.

[0022] Numerous patent applications describe the co-processing of renewable raw materials with fossil raw materials in order to produce gasoil fractions or kerosene fractions, or both, which incorporate a portion of biogenic carbon.

[0023] For example, in documents FR 2 949 475, EP 1 693 432 and EP 2 046 917 B1, the incorporation of renewable lipid raw materials containing triglycerides with a gasoil fraction (which is a petroleum fossil raw material) into a hydrotreating process using co-processing has been described. This incorporation makes it possible to produce renewable gasoil fractions and integrate them directly into the diesel pool obtained from fossil resources without investing in a dedicated hydrotreating unit. The advantages of co-processing raw materials containing triglycerides with fossil petroleum fractions compared to processing pure lipid raw materials are described in great detail in document FR 2 949 475 A1, such as, for example:

[0024] - Limiting polymerization related to the thermal instability of renewable raw materials,

[0025] - Reducing the content of sulfur, nitrogen and aromatics by dilution,

[0026] - Limiting the exotherm related to the hydrotreating of biological raw materials,

[0027] - Reducing the content of CO and CO2 in the gaseous effluent: limiting the inhibitory effect of CO on catalytic activity and limiting the corrosion risk in the presence of water and CO2,

[0028] - Increasing the solubility of hydrogen in the mixture to be treated.

[0029] According to the incorporation rate at the inlet of the process, this hydrotreating process makes it possible to essentially produce a renewable gasoil fraction, i.e., a fraction having an initial boiling point of 250 °C or 280 °C and a final boiling point ranging up to 340 °C or 370 °C.

[0030] In addition to renewable gasoil, the hydrocracking process also makes it possible to produce lighter biogenic products such as bio-kerosene and bio-naphtha.

[0031] In the context of the energy transition, the production of bio-kerosene (or SAF) has attracted increasing attention compared to the production of renewable diesel. On the other hand, the upgrading of bioresources into bio-naphtha for the petrochemical industry (aimed at producing olefins, BTX aromatics, polymers, cosmetics, etc.) has also become increasingly prominent. Refineries are therefore increasingly interested in technical solutions that make it possible to incorporate bio-kerosene into fossil kerosene and produce bio-naphtha for the petrochemical industry.

[0032] It is described in invention WO 2009 / 148909 A2 that pure raw materials containing triglycerides such as palm oil and animal fats can be converted in a sequence of steps of hydrotreating (on a sulfided NiMo catalyst supported on alumina) and hydrocracking (on a Pt-Pd catalyst supported on amorphous silica-alumina) in order to produce bio-naphtha with a yield of up to 28 wt%.

[0033] Patent application WO 2011 / 012439 A1 describes that lipid raw materials can be converted into n-alkanes and propane by hydrodeoxygenation and decarbonylation on a conventional hydrotreating catalyst. These n-alkanes are then mixed with fossil naphtha and injected into a steam cracking unit for the production of olefins, dienes, and aromatics.

[0034] Document EP 2 143 777 A1 describes a process for hydrocracking a feedstock consisting of a mixture of vacuum gasoil and a vegetable or animal fat feedstock, using a sequence of a hydrotreating catalyst (of the NiMo / Al2O3 type), followed by a hydrocracking catalyst (of the NiMo / zeolite type) and then a post-treatment catalyst (of the hydrodesulfurization type), making it possible to obtain a gasoil with a very low sulfur content. According to the invention, the incorporation of a bio-feedstock into the vacuum gasoil makes it possible to significantly increase the yield of the gasoil fraction, but this unfortunately results in a decrease in the kerosene yield. For example, this document states that in the case of incorporating 10 wt% of soybean oil into the vacuum gasoil, the yield of the gasoil fraction increases by 6%, but the yield of the kerosene fraction decreases by more than 3%. On the other hand, the obtained gasoil fraction has deteriorated low-temperature properties: the cloud point is 3 °C higher than that of the fossil gasoil obtained without incorporating soybean oil.

[0035] It is well known that under hydrotreating operating conditions, the n-alkanes from lipid feedstocks are hardly converted. At the end of the process, it is found that the main products are thus n-alkanes with the same number of carbon atoms or only one unit lower compared to the starting carboxylic acid chains present in the triglycerides. Currently, the most abundant lipid feedstocks for biofuel production are rapeseed oil, soybean oil, palm oil and their derivatives, and to a lesser extent used cooking oil and animal fats. These renewable feedstocks mainly contain triglycerides with fatty acid chains containing 16 and 18 carbon atoms. Thus, the main products obtained after hydrotreating will be n-alkanes mainly containing 15 to 18 carbon atoms. Therefore, the products of these biological feedstocks will be found mainly in the gas oil fraction, i.e., the fraction with an initial boiling point and a final boiling point in the range extending from 220 to 390 °C.

[0036] In this case, an additional selective hydrocracking step is required to obtain a bio-kerosene fraction.

[0037] Patent US8039682 describes a process for producing kerosene from renewable feedstocks, optionally co-processed with fossil feedstocks, which includes steps of hydrotreating, hydrodeoxygenation, isomerization and selective hydrocracking in the presence of a multifunctional catalyst or a series of catalysts, a gas / liquid separation step of the obtained effluent, followed by a step of separating the alkane effluent to produce a jet engine fuel effluent and a light naphtha effluent and an effluent heavier than the jet engine fuel, and subsequently recycling the effluent heavier than the jet engine fuel to the reaction zone, wherein the recycle / feed volume ratio is from 0.1 to 8.

[0038] Finally, if a catalytic system capable of hydroisomerizing and / or selectively hydrocracking the compounds of the gas oil hydrocarbon fraction into a light kerosene fraction can be obtained, then at this time it will be possible to produce large amounts of (bio)kerosene from a very wide range of feedstocks without modifying the existing process. However, to the knowledge of the applicant, and as emphasized by all the previously reported examples, the existing knowledge does not allow for this type of conversion.

[0039] The applicant has found that using a process for producing middle distillates (the process includes a hydrocracking step using a pre-hydrotreated fossil hydrocarbon feedstock mixed with a renewable feedstock) and a specific catalyst sequence, without changing the hydrocracking process of the fossil feedstock, enables the production of kerosene and gas oil fractions with a high yield including a high degree of biogenic carbon incorporation.

[0040] In particular, the following sequence is used: a first hydrocracking catalyst is used in a first catalytic zone, the first hydrocracking catalyst comprising a macroporous zeolite, preferably having at least one opening of at least 12MR, and metals from Groups VIB and VIII of the Periodic Table, and subsequently, without any separation between the first catalytic zone and the second catalytic zone, a second catalyst is used in the second catalytic zone, the second catalyst comprising at least one Group VIB metal of the Periodic Table and / or at least one Group VIII metal of the Periodic Table and a support comprising at least one zeolite having a BEA structure code, such that it is possible to:

[0041] - Improve the selectivity to the kerosene fraction compared to that obtained in a hydrocracking process using only said first catalyst (if the first catalyst is used for the entire hydrocracking step, i.e., 100% by volume dedicated to the hydrocracking step), while at the same time improving the low-temperature properties of the gas oil and kerosene fractions compared to using any other catalyst or catalyst sequence known to those skilled in the art. Summary of the Invention

[0043] The subject of the present invention is a method for producing middle distillates from at least one fossil hydrocarbon feedstock, at least 50% by weight of the compounds of which have an initial boiling point greater than 250 °C and a final boiling point less than 800 °C, the fossil hydrocarbon feedstock being co-processed with at least one renewable feedstock selected from vegetable oils, algal oils, edible oils, and animal fats, which may be fresh or used, alone or in admixture, and feedstocks obtained from the reprocessing of biomass / plastics / tyres / and household waste, alone or in admixture, the method comprising a step of hydrotreating the feedstock mixture in the presence of hydrogen and at least one hydrotreating catalyst and a step of hydrocracking at least a part and preferably all of the hydrotreated feedstock, the hydrocracking step being carried out at a temperature of 200 °C to 480 °C, at a total pressure of 1 MPa to 25 MPa, at a hydrogen volume to hydrocarbon feedstock volume ratio of 80 to 5000 litres / litre and at a space velocity (HSV) defined by the ratio of the volume flow rate of the liquid hydrocarbon feedstock to the volume of catalyst charged to the reactor of 0.1 to 50 h -1 and the step of hydrocracking the hydrotreated feedstock comprises at least:

[0044] a) a step of contacting at least a part and preferably all of the hydrotreated feedstock with at least one first catalyst in a first catalytic zone, the first catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support comprising at least one zeolite having at least a series of channels the openings of which are defined by a ring of 12 oxygen atoms (12MR) and at least one binder,

[0045] b) Then, in a second catalytic zone, all the effluents from step a) are contacted with a second catalyst without an intermediate separation step between the first catalytic zone and the second catalytic zone, the second catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprising at least one zeolite having a BEA structure code and at least one binder.

[0046] An advantage of the present invention is to provide a method for producing middle distillates using a specific sequence of catalysts in a hydrocracking step, which method enables a high kerosene yield to be obtained and improved low-temperature properties of the kerosene and gas oil distillates compared to those obtained in the prior art.

[0047] In particular, an advantage of the present invention is to provide a hydrocracking method which enables the selectivity for the kerosene fraction to be mainly improved and at the same time enables improved low-temperature properties of the kerosene and gas oil distillates compared to using catalysts or catalyst sequences of the prior art.

[0048] For the purposes of the present invention, the different embodiments shown can be used alone or in combination with each other without any limitation on the combination.

[0049] For the purposes of the present invention, different parameter ranges of a given step, such as a pressure range and a temperature range, can be used alone or in combination. For example, for the purposes of the present invention, a preferred range of pressure values can be combined with a more preferred range of temperature values.

[0050] Hereinafter, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by D.R. Lide, 81st edition, 2000 - 2001). For example, Group VIII according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification, and Group VIB corresponds to the metals in column 6.

[0051] Hereinafter, the expressions “... to... (of between... and...)” and “... between... and...” are equivalent and mean that the limiting values of the interval are included in the range of the values. If this is not the case and the limiting values are not included in the described range, such an explicit statement will be provided by the present invention.

[0052] In the present specification, the expression "greater than..." is understood as strictly greater than and is represented by the symbol ">", and the expression "less than..." is understood as strictly less than and is represented by the symbol "<".

[0053] In the present specification, the total SiO2 / Al2O3 molar ratio of the zeolite is also referred to as SAR or the silica-alumina ratio. The SiO2 / Al2O3 molar ratio is measured by X-ray fluorescence.

[0054] Description of the Embodiments

[0055] The present invention relates to a process for producing middle distillates from at least one fossil hydrocarbon feedstock, at least 50% by weight of the compounds of which have an initial boiling point greater than 250 °C and a final boiling point less than 800 °C, the fossil hydrocarbon feedstock being mixed with at least one renewable feedstock selected from vegetable oils, algal oils and animal fats, which may be fresh or used, alone or in admixture, and a feedstock obtained from the reprocessing of plastics / tyres / and domestic waste, alone or in admixture.

[0056] Feedstock

[0057] A very diverse range of hydrocarbon feedstocks can be processed by the hydrocracking process according to the invention. The fossil hydrocarbon feedstock used in the hydrocracking process according to the invention is a hydrocarbon feedstock at least 50% by weight of the compounds of which have an initial boiling point greater than 250 °C and a final boiling point less than 800 °C, preferably at least 60% by weight, preferably at least 75% by weight and more preferably at least 80% by weight of the compounds having an initial boiling point greater than 250 °C and a final boiling point less than 800 °C.

[0058] The fossil hydrocarbon feedstock is advantageously selected from gas oils or LCO (light cycle oil) from a catalytic cracking unit, atmospheric distillates, vacuum distillates from the direct distillation of crude oil or from conversion units such as FCC, coking, H-oil or visbreaking units, feedstocks from units for extracting aromatics from lubricating oil base stocks or from solvent dewaxing of lubricating oil base stocks, distillates from fixed bed or fluidized bed desulphurization or hydroconversion processes of ATR (atmospheric residue) and / or VR (vacuum residue) and / or deasphalted oil. The above list is not restrictive. The feedstock preferably has a boiling point T5 greater than 200 °C, preferably greater than 340 °C, i.e. 95% by weight of the compounds present in the feedstock have a boiling point greater than 250 °C, and preferably greater than 340 °C.

[0059] According to the invention, a fossil hydrocarbon feedstock is processed in the process according to the invention, the fossil hydrocarbon feedstock being mixed with at least one renewable feedstock selected from vegetable oils, edible oils, algal oils and animal fats, which may be fresh or used, alone or in admixture, and a feedstock obtained from the reprocessing of biomass / plastics / tyres / and domestic waste, alone or in admixture.

[0060] The vegetable oil can advantageously be crude or fully or partially refined and be obtained from the following plants: rapeseed, sunflower, soybean, palm, palm kernel, olive, coconut, Jatropha, the list not being limiting. Algal oil or fish oil is also relevant. The animal fat is advantageously selected from lard or fats from residues from the food industry or from the catering industry.

[0061] These raw materials basically contain a chemical structure of the triglyceride type, which those skilled in the art also refer to as fatty acid triesters and free fatty acids. The fatty acid triesters thus consist of three fatty acid chains. These fatty acid chains in the triester form or the free fatty acid form have an unsaturation number per chain that is generally from 0 to 3, also known as the number of carbon-carbon double bonds per chain, but it can be higher, especially for oils derived from algae, which generally have 5 to 6 unsaturation numbers per chain.

[0062] More generally, the method according to the invention is capable of processing the above-mentioned raw materials alone or in admixture, regardless of the proportions.

[0063] Preferably, relative to the total mass of the raw materials processed in the method according to the invention, the content of renewable raw materials in the raw material mixture is from 0.5% by weight to 40% by weight, and preferably from 1% by weight to 35% by weight, preferably from 2% by weight to 30% by weight and more preferably from 5% by weight to 25% by weight.

[0064] These raw materials may contain metals and / or nitrogen and / or oxygen and / or sulfur. If appropriate, the method according to the invention may optionally advantageously include a liquid / gas separation step between the hydrotreating step and the hydrocracking step of the raw materials.

[0065] The nitrogen content of the raw materials processed in the method according to the invention is generally greater than 500 ppm by weight, preferably from 500 to 10,000 ppm by weight, more preferably from 700 to 4,000 ppm by weight and still more preferably from 1,000 to 4,000 ppm by weight. The sulfur content of the raw materials processed in the method according to the invention is advantageously from 0.01% by weight to 5% by weight, preferably from 0.2% by weight to 4% by weight and still more preferably from 0.5% by weight to 3% by weight.

[0066] The raw material may optionally contain metals. The combined nickel and vanadium content of the raw materials processed in the method according to the invention is preferably less than 5 ppm by weight, preferably less than 3 ppm by weight and still more preferably less than 1 ppm by weight.

[0067] The raw material may optionally contain asphaltenes. The asphaltene content is generally less than 3,000 ppm by weight, preferably less than 1,000 ppm by weight and still more preferably less than 300 ppm by weight.

[0068] Due to the presence of renewable raw materials derived from biomass, the raw materials processed in the process according to the invention may also contain oxygenates. Their content varies highly depending on the raw materials to be converted in the process according to the invention. It is generally less than 50% by weight, and preferably less than 15% by weight, very preferably less than 5% by weight, still more preferably less than 2% by weight.

[0069] Embodiment

[0070] According to the invention, the process comprises a step of hydrotreating the raw materials in the presence of hydrogen and at least one hydrotreating catalyst. The hydrotreating step is preferably carried out at a temperature of 200 °C to 450 °C, at a pressure of 2 to 25 MPa, at a space velocity of 0.1 to 6 h -1 and with an amount of hydrogen introduced such that the hydrogen liters / hydrocarbon liters volume ratio is from 100 to 5000 Nl / l.

[0071] The operating conditions such as temperature, pressure, hydrogen recycle ratio and space-time velocity will vary highly depending on the nature of the raw materials, the quality of the desired products and the facilities available in the refinery.

[0072] Preferably, the hydrotreating step according to the invention is carried out at a temperature of 250 to 450 °C, very preferably 300 to 430 °C, at a pressure of 5 to 20 MPa, at a space velocity of 0.2 to 5 h -1 and with an amount of hydrogen introduced such that the hydrogen liters / hydrocarbon liters volume ratio is from 300 to 3000 Nl / l.

[0073] Conventional hydrotreating catalysts can advantageously be used in supported or unsupported form, preferably containing at least one amorphous support and at least one hydrodehydrogenation element selected from at least one non-noble metal element from Group VIB and Group VIII, and generally being at least one element from Group VIB (from molybdenum or tungsten alone or in admixture) and at least one non-noble metal element from Group VIII (from nickel or cobalt alone or in admixture).

[0074] Preferably, the amorphous support is alumina or silica-alumina.

[0075] Preferred catalysts are NiMo, NiW, NiMoW or CoMo catalysts supported on alumina and NiMo, NiW or NiMoW catalysts supported on silica-alumina.

[0076] The effluent from the hydrotreating step, a part and preferably all of which enters the hydrocracking step a), generally contains a nitrogen content of preferably less than 300 ppm by weight, less than 200 ppm by weight, preferably less than 100 ppm by weight and preferably less than 50 ppm by weight.

[0077] The method according to the invention may advantageously include a separation step between the hydrotreating step and the hydrocracking step.

[0078] In one embodiment, the method according to the invention does not include a separation step between the hydrotreating step and the hydrocracking step.

[0079] According to the invention, the method includes a step of hydrocracking at least a part and preferably all of the hydrotreated feedstock, the hydrocracking step being carried out at a temperature of 200°C to 480°C, at a total pressure of 1 MPa to 25 MPa, at a ratio of hydrogen gas volume / hydrocarbon feedstock volume of 80 to 5000 liters / liter and at a space velocity (HSV) defined by the ratio of the volume flow rate of the liquid hydrocarbon feedstock / the volume of the catalyst charged to the reactor of 0.1 to 50 h -1 .

[0080] Preferably, the hydrocracking step of the method according to the invention is carried out in the presence of hydrogen at a temperature of 250°C to 480°C, preferably 320°C to 450°C, very preferably 330°C to 435°C, at a pressure of 2 to 25 MPa, preferably 3 to 20 MPa, at a space velocity of 0.1 to 20 h -1 , preferably 0.1 to 6 h -1 and preferably 0.2 to 3 h -1 and with an amount of hydrogen introduced such that the volume ratio of hydrogen liters / hydrocarbon liters is 100 to 3000 l / l.

[0081] These operating conditions for the method according to the invention generally make it possible to obtain a single-pass conversion to products having a boiling point of less than 340°C and still better less than 370°C of greater than 15% by weight and still more preferably 20% to 95% by weight.

[0082] In addition, the kerosene fraction produced by the method according to the invention has a crystal disappearance point of less than -20°C, preferably less than -30°C and still more preferably less than -47°C. The gas oil fraction produced by this method has a cloud point of less than 15°C, preferably less than 5°C and very preferably less than -5°C.

[0083] According to the invention, the step of hydrocracking at least a part and preferably all of the hydrotreated feedstock at least comprises:

[0084] a) a step of bringing the hydrotreated feedstock into contact with at least one first catalyst in a first catalytic zone, the first catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprising at least one zeolite having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR) and at least one binder,

[0085] b) Then, in the second catalytic zone, all the effluents from step a) are contacted with a second catalyst without an intermediate separation step between the first and second catalytic zones. The second catalyst comprises at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, and the support comprises at least one zeolite with a BEA structure code and at least one binder.

[0086] Preferably, the first catalyst used in the first catalytic zone of the hydrocracking step a), which comprises at least one metal from Group VIB of the Periodic Table and at least one metal from Group VIII of the Periodic Table, either alone or in combination, is preferably a sulfide phase catalyst.

[0087] Preferably, the metal from Group VIB of the Periodic Table is selected from tungsten and molybdenum, either alone or in combination. According to a preferred embodiment, the metal from Group VIB is molybdenum. According to another preferred embodiment, the metal from Group VIB is tungsten.

[0088] Preferably, the non-noble metals from Group VIII of the Periodic Table are selected from cobalt and nickel, either alone or in combination. According to a preferred embodiment, the non-noble metal from Group VIII is cobalt. According to another preferred embodiment, the non-noble metal from Group VIII is nickel.

[0089] Preferably, the catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII, the non-noble metal from Group VIII being selected from cobalt and nickel, either alone or in combination, and the metal from Group VIB being selected from tungsten and molybdenum, either alone or in combination.

[0090] In one embodiment, the following metal combinations are used: nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, cobalt-tungsten, and still more preferably nickel-molybdenum and nickel-tungsten.

[0091] In the case where the catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII, the content of the metal from Group VIB, calculated as the oxide equivalent, is advantageously 5 wt% to 40 wt%, preferably 10 wt% to 35 wt%, and very preferably 15 wt% to 30 wt% relative to the total mass of the catalyst, and the content of the non-noble metal from Group VIII, calculated as the oxide equivalent, is advantageously 0.5 wt% to 10 wt%, preferably 1 wt% to 8 wt%, and very preferably 1.5 wt% to 6 wt% relative to the total mass of the catalyst.

[0092] When the catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII, the catalyst is a sulfided catalyst.

[0093] Combinations of three metals can also be used, such as nickel-cobalt-molybdenum, nickel-molybdenum-tungsten, nickel-cobalt-tungsten.

[0094] In one embodiment, the following metal combinations are used: nickel-niobium-molybdenum, cobalt-niobium-molybdenum, nickel-niobium-tungsten, cobalt-niobium-tungsten, and the preferred combinations are: nickel-niobium-molybdenum, cobalt-niobium-molybdenum. Combinations of four metals can also be used, such as nickel-cobalt-niobium-molybdenum.

[0095] The catalyst may also advantageously contain at least one doping element selected from boron and phosphorus, and preferably phosphorus.

[0096] The first catalyst may also advantageously contain:

[0097] - Oxides of at least one doping element selected from boron and phosphorus, and preferably phosphorus, in an amount of 0.1% to 15% by weight, preferably 0.1% to 10% by weight, relative to the total mass of the catalyst.

[0098] - Oxides of at least one element selected from Group VB elements, and preferably niobium, in an amount of 0% to 60% by weight, preferably 0.1% to 50% by weight, and still more preferably 0.1% to 40% by weight, relative to the total mass of the catalyst.

[0099] - Oxides of at least one element selected from Group VIIA elements, and preferably fluorine, in an amount of 0% to 20% by weight, preferably 0.1% to 15% by weight, and still more preferably 0.1% to 10% by weight, relative to the total mass of the catalyst.

[0100] According to the invention, the support of the first catalyst used in the first catalytic zone of the hydrocracking step a) according to the invention comprises at least one zeolite and at least one binder, and the zeolite has at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR).

[0101] The binder (also called a porous mineral matrix) used in the support of the first catalyst advantageously consists of at least one refractory oxide, and the refractory oxide is preferably selected from alumina, silica-alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or in admixture. Preferably, the binder is selected from alumina and silica-alumina, either alone or in admixture. More preferably, the binder is alumina. The alumina can advantageously be in any form known to those skilled in the art. Very preferably, the alumina is γ-alumina, such as boehmite.

[0102] Preferably, the carrier of the first catalyst contains 20% to 99% by weight, preferably 30% to 99% by weight, and very preferably 50% to 95% by weight, and very preferably 60% to 95% by weight of a binder relative to the total weight of the carrier.

[0103] The zeolite used in the carrier of the first catalyst is advantageously selected from zeolites of the FAU, BEA, ISV, IWR, IWW, MEI, and UWY structure types, either alone or in admixture, and is preferably selected from zeolites of the FAU and BEA structure types, either alone or in admixture.

[0104] In a preferred embodiment, the zeolite is selected from Y zeolite and β zeolite, either alone or in admixture, and preferably the zeolite is Y zeolite, and very preferably dealuminated USY zeolite.

[0105] Preferably, the carrier of the first catalyst contains 1% to 80% by weight, preferably 1% to 70% by weight, still more preferably 5% to 50% by weight, and very preferably 5% to 40% by weight of at least one zeolite relative to the total mass of the carrier.

[0106] Preferably, the carrier of the first catalyst comprises the following components and preferably consists of:

[0107] - at least one zeolite in an amount of 1% to 80% by weight, preferably 1% to 70% by weight, still more preferably 5% to 50% by weight, and very preferably 5% to 40% by weight relative to the total mass of the carrier,

[0108] - at least the binder in an amount of 20% to 99% by weight, preferably 30% to 99% by weight, preferably 50% to 95% by weight, and very preferably 60% to 95% by weight relative to the total mass of the carrier.

[0109] In a preferred embodiment, the first catalyst contains only Y zeolite.

[0110] In another preferred embodiment, the first catalyst contains USY zeolite and β zeolite.

[0111] The zeolite is advantageously defined in the classification "Atlas of Zeolite Framework Types, 6th Revised Edition", Ch. Baerlocher, L. B. McCusker, D. H. Olson, 6th Edition, Elsevier, 2007, Elsevier.

[0112] The Y zeolite used in the carrier of the first catalyst advantageously has less than Preferably less than and preferably less than and still more preferably less than of the initial lattice parameter a0 of the unit cell. Preferably, the initial lattice parameter a0 of the unit cell is greater than and preferably greater than

[0113] The Y zeolite used in the support of the first catalyst advantageously has a specific surface area measured by physical adsorption of nitrogen according to the BET method of 550 to 1200 m 2 / g, preferably 600 to 1100 m 2 / g, and preferably 650 to 1050 m 2 / g.

[0114] According to a preferred embodiment of the present invention, the Y zeolite for the support of the catalyst a) used in the process according to the present invention is advantageously prepared from a Y zeolite of the FAU structure type which preferably has a total Si / Al atomic ratio of 2.3 to 2.8 after synthesis and is advantageously in the NaY form after synthesis. The Y zeolite of the FAU structure type advantageously undergoes one or more ion exchange steps before undergoing a dealumination step. The ion exchange makes it possible to partially or completely replace the alkali metal cations belonging to Group IA and Group IIA of the periodic table at the cation positions present in the as-synthesized Y zeolite of the FAU structure type with NH4 + cations, and preferably replace the Na + cation with an NH4 + cation.

[0115] The partial or complete exchange of alkali metal cations with NH4 + cations is understood to mean the exchange of 80% to 100%, preferably 85% to 99.5% and more preferably 88% to 99% of the said alkali metal cations with NH4 + cations. At the end of the ion exchange step, the remaining amount of alkali metal cations in the Y zeolite, and preferably the remaining amount of Na + cations, relative to the amount of alkali metal cations initially present in the Y zeolite, preferably the amount of Na + cations, is advantageously 0% to 20%, preferably 0.5% to 15%, and preferably 1.0% to 12%.

[0116] Preferably, this step is carried out using a solution containing at least one ammonium salt selected from ammonium chlorate, sulfate, nitrate, phosphate or acetate to carry out multiple ion exchanges, thereby at least partially removing the alkali metal cations present in the zeolite, and preferably the Na + cation. Preferably, the ammonium salt is ammonium nitrate NH4NO3.

[0117] Thus, at the end of the ion exchange step, the remaining content of the alkali metal cations and preferably Na + cations in the Y zeolite is preferably such that the molar ratio of alkali metal cations to aluminum and preferably the molar ratio of Na to Al is from 0:1 to 0.005:1, and more preferably from 0:1 to 0.008:1.

[0118] The desired molar ratio of alkali metal cations to aluminum, preferably the Na / Al ratio, is obtained by adjusting the NH4 + concentration of the ion exchange solution, the ion exchange temperature, and the number of ion exchange times. The NH4 + concentration of the ion exchange solution advantageously varies between 0.01 and 12 mol·l -1 and preferably between 1.00 and 10 mol·l -1 . The temperature of the ion exchange step advantageously ranges from 20 to 100 °C, preferably from 60 to 95 °C, preferably from 60 to 90 °C, more preferably from 60 to 85 °C, and still more preferably from 60 to 80 °C. The number of ion exchange times advantageously varies between 1 and 10 and preferably between 1 and 4.

[0119] Optionally, the obtained Y zeolite of the preferred FAU structure type can subsequently undergo a dealumination treatment step. The dealumination step can advantageously be carried out by any method known to those skilled in the art. Preferably, dealumination is carried out by heat treatment (referred to as "steam treatment") optionally in the presence of water vapor and / or by one or more acid attacks, which are advantageously carried out by treating with an aqueous solution of an inorganic or organic acid.

[0120] Preferably, the dealumination step is carried out by heat treatment followed by one or more acid attacks, or only one or more acid attacks are carried out.

[0121] Preferably, the optional heat treatment of the Y zeolite in the presence of water vapor is carried out at a temperature of 200 °C to 900 °C, preferably 300 °C to 900 °C, and still more preferably 400 °C to 750 °C. The duration of the heat treatment advantageously is greater than or equal to 0.5 hour, preferably 0.5 hour to 24 hours, and very preferably 1 hour to 12 hours. In the case of carrying out the heat treatment in the presence of water, the volume percentage of water vapor during the heat treatment advantageously is 5% to 100%, preferably 20% to 100%, and very preferably 40% to 100%. The volume fraction optionally present that is not constituted by water vapor is formed by air. The flow rate of the gas formed by water vapor and possibly air advantageously is from 0.2 l·h -1 ·g -1 to 10 l·h -1 ·g -1 .

[0122] The heat treatment enables the extraction of aluminum atoms from the structure of the Y zeolite while maintaining the total Si / Al atomic ratio of the treated zeolite constant.

[0123] The heat treatment step in the presence of water vapor can advantageously be repeated as many times as necessary to obtain a zeolite suitable for use as a catalyst support in the process according to the invention and having a lattice parameter a0 of the unit cell less than preferably less than and preferably less than and still more preferably less than of the zeolite.

[0124] The heat treatment step optionally in the presence of water vapor is advantageously followed by an acid etching step. The acid etching makes it possible to partially or completely remove the aluminic debris from the heat treatment step in the presence of water vapor, which may partially block the pores of the dealuminated zeolite; the acid etching thus makes it possible to unclog the pores of the dealuminated zeolite.

[0125] The acid etching can advantageously be carried out by suspending the Y zeolite, optionally pre-treated by heat treatment, in an aqueous solution containing an inorganic acid or an organic acid. The inorganic acid can be nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid or boric acid. The organic acid can be formic acid, acetic acid, oxalic acid, tartaric acid, maleic acid, malonic acid, malic acid, lactic acid or any other water-soluble organic acid. The concentration of the inorganic acid or organic acid in the solution is advantageously between 0.01 and 2.0 mol·l -1 and preferably between 0.5 and 1.0 mol·l -1 varying. The temperature of the acid etching step is advantageously from 20 to 100 °C, preferably from 60 to 95 °C, preferably from 60 to 90 °C and more preferably from 60 to 80 °C. The duration of the acid etching is advantageously from 5 minutes to 8 hours, preferably from 30 minutes to 4 hours, and preferably from 1 hour to 2 hours.

[0126] At the end of the heat treatment step optionally in the presence of water vapor and the optional acid etching step, the method of modifying the Y zeolite advantageously includes at least one step of partially or completely exchanging the alkali metal cations and preferably Na + cations still present at the cationic sites in the Y zeolite. The ion exchange step is carried out in a manner similar to the above ion exchange step.

[0127] At the end of the heat treatment step optionally in the presence of water vapor and the optional acid etching step and the optional alkali metal cations and preferably Na +At the end of the partial or total exchange step of the cations, the method for modifying the Y zeolite may include a calcination step. This calcination makes it possible to remove the organic substances present within the pores of the zeolite, such as those provided by the acid etching step or by the step of partial or total exchange of alkali metal cations. In addition, this calcination step makes it possible to produce the protonated form of the Y zeolite and to confer acidity thereto for its applications.

[0128] The calcination can advantageously be carried out in a muffle furnace or a tube furnace, under dry air or in an inert atmosphere, in a swept bed or a traversed bed. The calcination temperature is advantageously from 200 to 800 °C, preferably from 450 to 600 °C, and preferably from 500 to 550 °C. The duration of the calcination hold is advantageously from 1 to 20 hours, preferably from 6 to 15 hours, and preferably from 8 to 12 hours.

[0129] Thus, the zeolite obtained has an initial lattice parameter a0 of the unit cell less than preferably less than and preferably less than and still more preferably less than , and a specific surface area measured by physical adsorption of nitrogen according to the BET method of 550 to 1200 m 2 / g, preferably 600 to 1100 m 2 / g, and preferably 650 to 1050 m 2 / g.

[0130] In a preferred embodiment in which the support of the first catalyst contains, in addition to the USY zeolite, a β zeolite, the β zeolite preferably has a total SiO2 / Al2O3 molar ratio or SAR of 10 to 100, preferably 20 to 50, and preferably 20 to 30. The β zeolite used in the support of the first catalyst according to the invention advantageously has a specific surface area measured by physical adsorption of nitrogen according to the BET method of 400 to 800 m 2 / g, preferably 500 to 750 m 2 / g, and preferably 550 to 700 m 2 / g.

[0131] The β zeolite is generally synthesized from a reaction mixture containing a structuring agent. The use of structuring agents is well known to those skilled in the art: for example, patent US 3,308,069 describes the use of tetraethylammonium hydroxide, and patent US 5,139,759 describes the use of tetraethylammonium cations derived from tetraethylammonium halide compounds. Another standard method for preparing β zeolite is given in the book "Verified Synthesis of Zeolitic Materials".

[0132] In the preferred embodiment in which the support of the first catalyst comprises USY zeolite and beta zeolite, the first catalyst comprises the following components and preferably consists of:

[0133] - From 0.9 wt% to 79.9 wt%, preferably from 1 wt% to 70 wt%, and preferably from 5 wt% to 50 wt%, and very preferably from 5 wt% to 40 wt% based on the total weight of the support, of Y zeolite having an initial lattice parameter a0 of the unit cell smaller than ;

[0134] - From 0.1 wt% to 6 wt%, preferably from 0.2 wt% to 5 wt%, and preferably from 0.5 wt% to 5 wt% based on the total weight of the support, of beta zeolite; and

[0135] - From 20 wt% to 99 wt%, preferably from 30 wt% to 99 wt%, and very preferably from 50 wt% to 95 wt%, and still more preferably from 60 wt% to 95 wt% based on the total weight of the support, of at least one binder.

[0136] According to step b) of the process according to the invention, all the effluents from step a) are contacted with a second catalyst in a second catalytic zone, without an intermediate separation step between the first catalytic zone and the second catalytic zone, wherein the second catalyst comprises at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprising at least one zeolite with BEA structure code and at least one binder.

[0137] Preferably, the effluent from step a) is fed to the second catalytic zone without an intermediate gas / liquid separation step.

[0138] Preferably, the second catalyst used in the second catalytic zone of the hydrocracking step b), which comprises at least one metal from Group VIB of the Periodic Table and at least one metal from Group VIII of the Periodic Table, alone or in admixture, is preferably a catalyst in sulfide form.

[0139] Preferably, the metal from Group VIB of the Periodic Table is selected from tungsten and molybdenum, alone or in admixture. According to one preferred embodiment, the metal from Group VIB is molybdenum. According to another preferred embodiment, the metal from Group VIB is tungsten.

[0140] Preferably, the non-noble metal from Group VIII of the Periodic Table is selected from cobalt and nickel, alone or in admixture. According to one preferred embodiment, the non-noble metal from Group VIII is cobalt. According to another preferred embodiment, the non-noble metal from Group VIII is nickel.

[0141] Preferably, the second catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII. The non-noble metal from Group VIII is selected from cobalt and nickel, either alone or in combination, and the metal from Group VIB is selected from tungsten and molybdenum, either alone or in combination.

[0142] In one embodiment, the following metal combinations are used: nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, cobalt-tungsten; preferred combinations are: nickel-molybdenum and nickel-tungsten.

[0143] When the second catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII, the content of the metal from Group VIB, in terms of oxide equivalent, is advantageously 5 wt% to 40 wt%, preferably 10 wt% to 35 wt%, and very preferably 15 wt% to 30 wt% relative to the total mass of the catalyst, and the content of the non-noble metal from Group VIII, in terms of oxide equivalent, is advantageously 0.5 wt% to 10 wt%, preferably 1 wt% to 8 wt%, and very preferably 1.5 wt% to 6 wt% relative to the total mass of the catalyst.

[0144] When the second catalyst comprises a combination of at least one metal from Group VIB and at least one non-noble metal from Group VIII, the catalyst is a sulfided catalyst.

[0145] Combinations of three metals can also be used, such as nickel-cobalt-molybdenum, nickel-molybdenum-tungsten, nickel-cobalt-tungsten.

[0146] In one embodiment, the following metal combinations are used: nickel-niobium-molybdenum, cobalt-niobium-molybdenum, nickel-niobium-tungsten, cobalt-niobium-tungsten; preferred combinations are: nickel-niobium-molybdenum, cobalt-niobium-molybdenum. Combinations of four metals can also be used, such as nickel-cobalt-niobium-molybdenum.

[0147] The catalyst may also advantageously contain at least one doping element selected from boron and phosphorus, and preferably phosphorus.

[0148] The second catalyst may also advantageously contain:

[0149] - at least one doping element selected from boron and phosphorus, and preferably phosphorus, in an amount of 0.1 wt% to 15 wt%, preferably 0.1 wt% to 10 wt%, by weight of oxide relative to the total mass of the catalyst,

[0150] - at least one element selected from Group VB, and preferably niobium, in an amount of 0 wt% to 60 wt%, preferably 0.1 wt% to 50 wt%, and still more preferably 0.1 wt% to 40 wt%, by weight of oxide relative to the total mass of the catalyst,

[0151] - From 0% to 20% by weight, preferably from 0.1% to 15% by weight, and still more preferably from 0.1% to 10% by weight, based on the total mass of the catalyst, of at least one element selected from Group VIIA, and preferably fluorine, calculated as the oxide weight.

[0152] According to the present invention, the support of the second catalyst used in the second catalytic zone of the hydrocracking step b) according to the present invention comprises at least one zeolite with a BEA structure code and at least one binder.

[0153] Preferably, the zeolite with a BEA structure code is beta zeolite, and preferably beta zeolite having a total silica / alumina molar ratio SAR of 10 to 300, preferably 10 to 100, preferably 10 to 50, preferably 10 to 30, more preferably 10 to 25, still more preferably 12 to 24, and still more preferably 15 to 24.

[0154] The beta zeolite is generally synthesized from a reaction mixture containing a structuring agent. The use of structuring agents is well known to those skilled in the art: for example, Patent US 3,308,069 describes the use of tetraethylammonium hydroxide, and Patent US 5,139,759 describes the use of tetraethylammonium cations derived from tetraethylammonium halide compounds. Another standard method for preparing beta zeolite is given in the book "Verified Synthesis of Zeolitic Materials" (Elsevier, 2001).

[0155] The beta zeolite used in the support of the second catalyst according to the present invention advantageously has an average crystal size of less than 500 nm, preferably less than 350 nm. Advantageously, these crystals can be in the form of aggregates with a size of up to 50 μm, preferably less than 25 μm. In addition, the beta zeolite used in the support of catalyst b) according to the present invention has a BET surface area measured by nitrogen physisorption of 500 to 800 m 2 / g, preferably 500 to 750 m 2 / g, and preferably 550 to 720 m 2 / g, a mesopore volume greater than 0.2 ml / g, preferably greater than 0.40 ml / g, measured by BJH, and an external surface area of at least 120 m 2 / g, preferably at least 140 m 2 / g, very preferably at least 150 m 2 / g, and still more preferably 150 to 300 m 2 / g. Finally, preferably, the proportion of the external surface area relative to the total BET surface area of the beta zeolite contained in the support of catalyst b) is 15% to 50%, very preferably 18% to 40%, and still more preferably 21% to 37%.

[0156] The binder (also known as the porous mineral matrix) used in the support of the second catalyst advantageously consists of at least one refractory oxide, which is preferably selected from alumina, silica-alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or in admixture. Preferably, the binder is selected from alumina and silica-alumina, either alone or in admixture. More preferably, the binder is alumina. The alumina can advantageously be in any form known to those skilled in the art. Very preferably, the alumina is γ-alumina, such as boehmite.

[0157] Preferably, the support of the second catalyst contains 20 wt% to 99 wt%, preferably 30 wt% to 99 wt%, and very preferably 50 wt% to 95 wt%, and very preferably 60 wt% to 95 wt% of the binder, based on the total weight of the support.

[0158] Preferably, the support of the second catalyst contains the following components and preferably consists of:

[0159] - 1 wt% to 70 wt%, preferably 1 wt% to 50 wt%, preferably 1.5 wt% to 40 wt%, and still more preferably 2 wt% to 30 wt% of the β-zeolite, based on the total mass of the support,

[0160] - at least the binder in an amount of 30 wt% to 99 wt%, preferably 50 wt% to 99 wt%, preferably 60 wt% to 98 wt%, and very preferably 70 wt% to 98 wt%, based on the total mass of the support.

[0161] The second catalyst used in step b) of the process according to the invention can advantageously contain at least one other zeolite in the support of the second catalyst. If appropriate, the other zeolite is advantageously selected from zeolites having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR), particularly selected from zeolites of the FAU, BEA, ISV, IWR, IWW, MEI, UWY, MFI, MTW structure types or IZM-2 zeolite, either alone or in admixture, and preferably selected from zeolites of the FAU and BEA structure types, either alone or in admixture. Preferably, the second catalyst can contain another zeolite of the FAU structure code in addition to the zeolite of the BEA structure code, and preferably Y-zeolite.

[0162] Preferably, the Y-zeolite that can be used for the second catalyst has an initial lattice parameter a0 of the unit cell less than Preferably less than and preferably less than and still more preferably less than and 550 to 1200 m 2 / g, preferably 600 to 1100 m 2 / g, and preferably 650 to 1050 m 2 / g of specific surface area measured by nitrogen physical adsorption according to the BET method.

[0163] Preferably, the Y zeolite can be prepared according to the same method as the Y zeolite used in step a) of the method according to the present invention.

[0164] In this case, the support of the second catalyst used in the method according to the present invention comprises at least one zeolite of BEA structure code and at least one Y zeolite, and at least one binder, and the support comprises the following components and is preferably composed of, preferably:

[0165] - with respect to the total mass of the support, 1 wt% to 50 wt%, preferably 1 wt% to 30 wt%, preferably 1.5 wt% to 20 wt%, and still more preferably 2 wt% to 30 wt% of the β zeolite,

[0166] - with respect to the total mass of the support, 0.5 wt% to 50 wt%, preferably 1 wt% to 30 wt%, preferably 1.5 wt% to 10 wt%, and still more preferably 2 wt% to 5 wt% of the Y zeolite,

[0167] - with respect to the total mass of the support, 30 wt% to 98.5 wt%, preferably 40 wt% to 98 wt%, preferably 70 wt% to 97 wt%, and very preferably 65 wt% to 96 wt% of at least the binder.

[0168] In this case, the second catalyst used in step b) of the method according to the present invention is preferably different from the first catalyst used in step a) of the method.

[0169] In the hydrocracking step, the volume fraction of the first catalyst used in step a) with respect to the total of the two catalysts used in steps a) and b) is preferably 50 vol% to 95 vol%, and preferably 60 vol% to 95 vol%, very preferably 65 vol% to 90 vol%, and still more preferably 65 vol% to 85 vol%.

[0170] Preferably, the volume fraction of the second catalyst used in step b) with respect to the total of the two catalysts used in steps a) and b) is 5 vol% to 50 vol%, and preferably 5 vol% to 40 vol%, very preferably 10 vol% to 35 vol%, and still more preferably 15 vol% to 35 vol%.

[0171] The method according to the present invention for producing middle distillates can advantageously be carried out according to any embodiment known in the prior art.

[0172] The method can advantageously be carried out in one or more steps, in one or more reactors, in a fixed bed or in a fluidized bed. It can be carried out with or without recycle after the hydrotreating step aimed at removing any sulfur, nitrogen or oxygen compounds that may be present in the feedstock. In the case where recycle is carried out, this can be carried out at any position in the method, in the hydrotreating step or in the first catalytic zone of the hydrocracking step a).

[0173] In one embodiment of the "two-step" hydrocracking step, the effluent from step b) of the hydrocracking step is sent to a fractionation column to recover at least one middle distillate fraction and at least one heavy fraction containing unconverted compounds, and advantageously the heavy fraction is sent to a second hydrocracking step in the presence of hydrogen and a hydrocracking catalyst or to the hydrotreating step a).

[0174] Preparation of the first and second catalysts according to the present invention

[0175] The first and second catalysts used respectively in steps a) and b) of the hydrocracking step of the process according to the invention are advantageously prepared according to conventional methods used in the prior art.

[0176] In particular, the catalyst is prepared according to a preparation method comprising the following steps:

[0177] - A step of preparing a support, comprising:

[0178] - Mixing at least one porous mineral matrix with:

[0179] In the case of the first catalyst, at least one zeolite having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR),

[0180] In the case of the second catalyst, at least one zeolite with a BEA structure code having an SAR of less than 25,

[0181] and

[0182] - Shaping the mixture;

[0183] - Introducing at least one hydrodehydrogenation element selected from the elements of group VIB of the periodic table, preferably molybdenum and tungsten, non-noble metal elements of group VIII of the periodic table, preferably cobalt and nickel, and mixtures thereof, preferably nickel and cobalt, and mixtures thereof, onto the support by the following method:

[0184] - Adding at least one precursor of the element during shaping, thereby introducing at least a portion of the element, and / or

[0185] - Impregnating the support with at least one precursor of the element

[0186] - Optionally, a drying and / or calcination step at the end of the step of preparing the support and / or introducing at least one hydrogenation-dehydrogenation element.

[0187] More particularly, the first catalyst is prepared according to a preparation method comprising the following steps:

[0188] - Preparing a zeolite having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR) according to a method known in the prior art, preferably Y zeolite,

[0189] - Mixing with a porous mineral matrix and shaping to obtain the support,

[0190] - Introducing at least one hydrogenation-dehydrogenation element onto the support by at least one of the following methods: (i) adding at least one precursor of the element during shaping to introduce at least a part of the element, (ii) impregnating the support with at least one precursor of the hydrogenation-dehydrogenation element,

[0191] - Optionally, drying and / or calcining the product obtained at the end of each of the above preparation steps.

[0192] Similarly, more particularly, the second catalyst is prepared according to a preparation method comprising the following steps:

[0193] - Preparing a zeolite with a BEA structure code having a SAR of less than 25 according to a method known in the prior art,

[0194] - Mixing with a porous mineral matrix and shaping to obtain a support,

[0195] - Introducing at least one hydrogenation-dehydrogenation element onto the support by at least one of the following methods: (i) adding at least one precursor of the element during shaping to introduce at least a part of the element, (ii) impregnating the support with at least one precursor of the hydrogenation-dehydrogenation element,

[0196] - Optionally, drying and / or calcining the product obtained at the end of each of the above preparation steps.

[0197] Preferably, the porous mineral matrix is derived from an alumina gel having a crystallite size of 2 to 35 nm.

[0198] Preferably, the alumina gel used contains a sulfur content of 0.001% to 1% by weight, preferably 0.001% to 0.40% by weight, very preferably 0.003% to 0.33% by weight, and more preferably 0.005% to 0.25% by weight.

[0199] Preferably, the alumina gel used contains from 0.001% to 1% by weight, preferably from 0.001% to 0.15% by weight, very preferably from 0.0015% to 0.10% by weight, and from 0.002% to 0.040% by weight of sodium content.

[0200] The alumina gel used advantageously has a high degree of dispersion, which makes it possible to facilitate the step of shaping the gel according to any method known to those skilled in the art, and in particular by kneading and extrusion, by granulation, and by a technique known as the oil-drop technique.

[0201] The alumina has a specific surface area and pore distribution that are calibrated and suitable for its use in the process of hydrocracking the hydrocarbon feedstock.

[0202] Preferably, the alumina is purely mesoporous and does not contain micropores.

[0203] Preferably, the support advantageously has a specific surface area greater than 100 m 2 / g, and a mesopore volume greater than or equal to 0.5 ml / g, preferably greater than or equal to 0.6 ml / g.

[0204] The mesopore volume of the support is defined as the volume contained in voids with an average diameter of 2 to 50 nm, and is measured using the mercury intrusion method.

[0205] Preferably, the alumina prepared and used in the present invention is non-mesoporous structured alumina.

[0206] The support can be advantageously shaped by any technique known to those skilled in the art. The shaping can be carried out, for example, by extrusion, by granulation, by the oil-drop condensation method, by rotary granulation, or by any other method known to those skilled in the art.

[0207] The support is preferably shaped into particles of various shapes and sizes. They are usually used in the form of cylindrical extrudates or multi-lobed extrudates, such as three-lobed, four-lobed or multi-lobed extrudates in straight or twisted form, but can optionally be manufactured and used in the form of crushed powder, tablets, rings, beads or wheels. However, the catalyst is advantageously in the form of an extrudate having a diameter of 0.5 to 5 mm, and more particularly 0.7 to 3 mm, and still more particularly 1.0 to 2.5 mm. The shape is cylindrical (which can be or not be hollow), twisted cylindrical, multi-lobed (e.g. 2, 3, 4 or 5 lobes) or ring. Any other shape can be used.

[0208] One of the preferred shaping methods comprises co-kneading the zeolite with a binder in the form of a wet gel, preferably alumina, for several tens of minutes, preferably 10 to 40 minutes, and subsequently passing the paste thus obtained through a die to form an extrudate preferably having a diameter of 0.5 to 5 mm.

[0209] According to another preferred shaping method, the zeolite can be introduced during the synthesis of the porous mineral matrix. For example, according to this preferred embodiment of the invention, the zeolite, preferably zeolite Y and optionally zeolite β, is added during the synthesis of the porous mineral matrix, such as a silica-alumina matrix: in this case, the zeolite can advantageously be added to a mixture consisting of an alumina compound and a completely soluble silica compound in an acidic medium.

[0210] According to the invention, the starting material obtained at the end of the shaping step is subsequently subjected to a calcination step at a temperature of 500 °C to 1000 °C for 2 to 10 hours in the presence or absence of an air stream containing up to 60% by volume of water.

[0211] Preferably, the calcination step is carried out at a temperature of 540 °C to 850 °C.

[0212] Preferably, the calcination step is carried out for a duration of 2 hours to 10 hours.

[0213] When the binder is alumina gel, also known as boehmite, the calcination step allows the conversion of boehmite into the final alumina.

[0214] Elements from Group VIB and / or Group VIII can optionally be introduced during the shaping step by adding at least one compound of the element to introduce at least a portion of the element.

[0215] The introduction of at least one hydrodehydrogenation element can advantageously be accompanied by the introduction of at least one promoter element selected from phosphorus, boron, silicon and preferably phosphorus, and optionally by the introduction of elements from Group VIIA and / or Group VB. The shaped solid is optionally dried at a temperature of 60 °C to 250 °C and optionally calcined at a temperature of 250 °C to 800 °C for a duration of 30 minutes to 6 hours.

[0216] The step of introducing at least one hydrodehydrogenation element is advantageously carried out by methods known to those skilled in the art, in particular by one or more operations of impregnating the shaped and calcined or dried, and preferably calcined, support with a solution containing a precursor of an element from Group VIB and / or Group VIII, optionally a precursor of at least one promoter element and optionally a precursor of at least one element from Group VIIA and / or Group VB.

[0217] Preferably, the introduction is carried out by the method of dry impregnation with a solution containing a precursor with hydrogenation / dehydrogenation functionality (i.e., an element from Group VIB and / or Group VIII), optionally followed by a drying step and preferably without a calcination step.

[0218] In the case where the catalyst of the present invention contains a non-noble metal from Group VIII, the metal from Group VIII is preferably introduced after or simultaneously with the Group VIB metal by one or more operations of impregnating the shaped and calcined support.

[0219] The introduction of at least one hydrogenation-dehydrogenation element can optionally be followed by drying at a temperature of 60°C to 250°C and optionally followed by calcination at a temperature of 250°C to 800°C.

[0220] The molybdenum source and tungsten source are advantageously selected from oxides and hydroxides, molybdic acid and tungstic acid and their salts, especially ammonium salts such as ammonium molybdate, ammonium heptamolybdate and ammonium tungstate, phosphomolybdic acid, phosphotungstic acid and their salts, silicomolybdic acid, silicotungstic acid and their salts. Oxides and ammonium salts such as ammonium molybdate, ammonium heptamolybdate and ammonium tungstate are preferably used.

[0221] The sources of non-noble metal elements from Group VIII that can be used are well known to those skilled in the art. For example, for non-noble metals, nitrates, sulfates, hydroxides, phosphates, halides (such as chlorides, bromides and fluorides), carboxylates (such as acetates and carbonates) will be used.

[0222] The preferred phosphorus source is orthophosphoric acid H3PO4, but its salts and esters such as ammonium phosphate are also suitable. Phosphorus can be introduced, for example, in the form of a mixture of phosphoric acid and a basic organic compound containing nitrogen such as ammonia water, primary and secondary amines, cyclic amines, compounds of the pyridine and quinoline families, and compounds of the pyrrole family. Phosphotungstic acid or tungstomolybdic acid can be used.

[0223] Without limiting the scope of the present invention, the phosphorus content is adjusted to form a dissolved and / or mixed compound on the support, such as tungsten-phosphorus or molybdenum-tungsten-phosphorus. These mixed compounds can be heteropoly anions. These compounds can be, for example, Anderson heteropoly anions.

[0224] The boron source can be boric acid, preferably orthoboric acid H3BO3, ammonium diborate or ammonium pentaborate, boron oxide or borate ester. Boron can be introduced, for example, in the form of a mixture of boric acid, an aqueous hydrogen peroxide solution and a basic organic compound containing nitrogen such as ammonia water, primary and secondary amines, cyclic amines, compounds of the pyridine and quinoline families, and compounds of the pyrrole family. Boron can be introduced, for example, through a solution of boric acid in a water / alcohol mixture.

[0225] Sources of elements from Group VB that can be used are well known to those skilled in the art. For example, in the case of niobium sources, oxides such as niobium pentoxide Nb2O5, niobic acid Nb2O5·H2O, niobium hydroxide, and polynioxy salts, niobium alkoxides of the formula Nb(OR1)3 (where R1 is an alkyl group), niobium oxalate NbO(HC2O4)5, or ammonium niobate can be used. Niobium oxalate or ammonium niobate is preferably used.

[0226] Sources of elements from Group VIIA that can be used are well known to those skilled in the art. For example, fluoride anions can be introduced in the form of hydrofluoric acid or its salts. These salts are formed with alkali metals, ammonium, or organic compounds. In the latter case, the salts are advantageously formed in the reaction mixture by reaction between the organic compound and hydrofluoric acid. Hydrolyzable compounds that can release fluoride anions into water, such as ammonium fluorosilicate (NH4)2SiF6, silicon tetrafluoride SiF4, or sodium fluorosilicate Na2SiF6, can also be used. Fluorine can be introduced, for example, by impregnation with an aqueous solution of hydrofluoric acid or ammonium fluoride.

[0227] Organic additives can be optionally added to any step of preparing the catalyst, and are preferably added to the impregnation solution alone or together with various metal precursors.

[0228] Before injecting the feedstock, the catalyst used in the process according to the invention is subjected to a sulfidation treatment before contacting with the feedstock to be treated so as to convert at least part of the metal species into sulfides. This activation treatment by sulfidation is well known to those skilled in the art and can be carried out in situ (i.e., in the reactor) or ex situ by any method already described in the literature. For the two catalysts used in this process, this treatment can be carried out simultaneously or successively.

[0229] Conventional sulfidation methods well known to those skilled in the art include heating the catalyst at a temperature of 150 to 800 °C, preferably 250 to 600 °C, in the presence of hydrogen sulfide (pure or in a stream of, for example, a hydrogen / hydrogen sulfide mixture), usually in a flow-through bed reaction zone.

[0230] The present invention is illustrated by the following examples, which are not limiting in any way. Examples:

[0231] Example 1: Preparation of support S1 containing Y zeolite and β zeolite

[0232] Support S1 was prepared by kneading-extruding 15 wt% of a zeolite having with a lattice parameter, a SiO2 / Al2O3 molar ratio (SAR) of 30, and 890 m 2Commercially available USY zeolite with a specific surface area measured by nitrogen physical adsorption according to the BET method of 670 m² / g and 5 wt% of β zeolite having a SiO₂ / Al₂O₃ molar ratio of 24 are used for preparation. The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 15 wt% of USY zeolite, 5 wt% of β zeolite and 80 wt% of alumina on a dry basis. 2 Commercially available β zeolite with a specific surface area measured by nitrogen physical adsorption according to the BET method of 670 m² / g and 5 wt% of β zeolite having a SiO₂ / Al₂O₃ molar ratio of 24 are used for preparation. The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 15 wt% of USY zeolite, 5 wt% of β zeolite and 80 wt% of alumina on a dry basis.

[0233] Example 2: Preparation of support S2 containing β zeolite with SAR < 25

[0234] Support S2 is prepared by kneading and extruding 5 wt% of commercially available β zeolite having a SiO₂ / Al₂O₃ molar ratio of 24 and a specific surface area of 670 m² / g measured by nitrogen physical adsorption according to the BET method in the presence of commercially available boehmite (Pural SB3 from Sasol). The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 5 wt% of β zeolite and 95 wt% of alumina on a dry basis. 2 Support S2 is prepared by kneading and extruding 5 wt% of commercially available β zeolite having a SiO₂ / Al₂O₃ molar ratio of 24 and a specific surface area of 670 m² / g measured by nitrogen physical adsorption according to the BET method in the presence of commercially available boehmite (Pural SB3 from Sasol). The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 5 wt% of β zeolite and 95 wt% of alumina on a dry basis.

[0235] Example 3: Preparation of support S3 containing Y zeolite

[0236] Support S3 is prepared by kneading and extruding 20 wt% of commercially available USY zeolite having lattice parameters, a SiO₂ / Al₂O₃ molar ratio of 30 and a specific surface area of 890 m² / g measured by nitrogen physical adsorption according to the BET method in the presence of commercially available boehmite (Pural SB3 from Sasol). The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 20 wt% of USY zeolite and 80 wt% of alumina on a dry basis. 2 Support S3 is prepared by kneading and extruding 20 wt% of commercially available USY zeolite having lattice parameters, a SiO₂ / Al₂O₃ molar ratio of 30 and a specific surface area of 890 m² / g measured by nitrogen physical adsorption according to the BET method in the presence of commercially available boehmite (Pural SB3 from Sasol). The obtained extrudates are dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contains 20 wt% of USY zeolite and 80 wt% of alumina on a dry basis.

[0237] Example 4: Preparation of support S4 (according to the present invention) containing β zeolite with SAR > 200

[0238] Support S2 is prepared by kneading and extruding 5 wt% of β zeolite having a SiO₂ / Al₂O₃ molar ratio of 250 and a specific surface area of 580 m² / g measured by nitrogen physical adsorption according to the BET method in the presence of commercially available boehmite (Pural SB3 from Sasol). 2Commercial β-zeolite with a specific surface area measured by nitrogen physical adsorption according to the BET method of / g was used for preparation. The obtained extrudates were dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support contained 5 wt% of β-zeolite and 95 wt% of alumina on a dry basis.

[0239] Example 5: Preparation of alumina support S5

[0240] Support S2 was prepared by kneading-extruding commercial boehmite (Pural SB3 from Sasol). The obtained extrudates were dried at 80 °C and then calcined at 600 °C in humid air (5 wt% water / kg dry air). The calcined support thus did not contain zeolite.

[0241] Example 6: Preparation of catalysts:

[0242] - C1: NiMoP supported on S1 (USY + β),

[0243] - C2: NiMoP supported on S2 (β alone, with SAR = 24),

[0244] - C3: NiMoP supported on S3 (USY),

[0245] - C4: NiMoP supported on S4 (β alone, with SAR = 250),

[0246] - C5: NiMoP supported on zeolite-free S5.

[0247] Catalysts C1, C2, C3, and C4 were prepared in the same way by dry impregnation of supports S1, S2, S3, and S4 with aqueous solutions containing elements Ni and Mo, respectively. The solution was obtained by dissolving the following precursors in water: nickel nitrate and ammonium heptamolybdate. The amount of dissolved precursors was adjusted according to the target concentration on the final catalyst. After dry impregnation, the catalysts were dried in air at 120 °C.

[0248] Catalyst C5 was prepared in two stages. Catalyst C5_int was first prepared from support S5 similar to catalysts C1 to C4, but with different target contents and similar drying. Subsequently, this catalyst C5_Int was dry impregnated with a triethylene glycol solution such that the TEG / Mo molar ratio was 0.5 mol / mol, and the volume balance consisting of the solvent was composed of 50% v / v water and 50% v / v ethanol. The final catalyst C5 was obtained after the final drying step at 100 °C.

[0249] The mass percentages in the catalysts are shown in the following table:

[0250] Table 1

[0251]

[0252] Example 7 (comparative): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst followed by a hydrocracking catalyst based on USY zeolite and beta zeolite.

[0253] Example 8 (comparative): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst followed by a hydrocracking catalyst based on USY zeolite alone.

[0254] Example 9 (according to the invention): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst, followed by a first hydrocracking catalyst based on USY zeolite and beta zeolite, and then a second hydrocracking catalyst based on beta zeolite having a SAR of 250. The volume ratio of the first hydrocracking catalyst to the second hydrocracking catalyst is 75 vol% and 25 vol%, respectively.

[0255] Example 10 (according to the invention): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst, followed by a first hydrocracking catalyst based on USY zeolite alone, and then a second hydrocracking catalyst based on beta zeolite having a SAR of 250. The volume ratio of the first hydrocracking catalyst to the second hydrocracking catalyst is 75 vol% to 25 vol%.

[0256] Example 11 (according to the invention): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst, followed by a first hydrocracking catalyst based on USY zeolite and beta zeolite, and then a second hydrocracking catalyst based on beta zeolite having a SAR of 24. The volume ratio of the first hydrocracking catalyst to the second hydrocracking catalyst is 75 vol% to 25 vol%.

[0257] Example 12 (according to the invention): Hydrocrack a mixture comprising 83 wt% vacuum gas oil and 17 wt% animal fat in a sequence of a hydrotreating catalyst, followed by a first hydrocracking catalyst based on USY zeolite alone, and then a second hydrocracking catalyst based on beta zeolite having a SAR of 24. The volume ratio of the first hydrocracking catalyst to the second hydrocracking catalyst is 75 vol% to 25 vol%.

[0258] For Examples 7 to 12, the characteristics of the feedstock, which is a mixture containing 83 wt% of vacuum gas oil and 17 wt% of animal fat, are given in Table 2.

[0259] Before injection into the hydrocracking step, the feedstock is pretreated with a hydrotreating catalyst at a total pressure of 14 MPa and at a temperature and HSV such that an organic nitrogen content of 10 ppm is obtained in the hydrotreated feedstock, i.e., at the inlet of the hydrocracking catalyst bed.

[0260] All the hydrotreated effluents from the hydrotreating section are sent directly to the hydrocracking section without an intermediate separation step. The temperature of the hydrocracking catalyst is controlled to obtain a total conversion of 86 wt% of the 370 °C+ fraction.

[0261] In Examples 9 to 12, the volume ratio of the first hydrocracking catalyst to the second hydrocracking catalyst is set to 75 / 25 vol%. There is no intermediate separation of the effluent between these two hydrocracking catalysts.

[0262] All the examples are compared at the same total pressure of 14 MPa, with the same total catalyst volume, and with the same feedstock flow rate.

[0263] The performance of the method is evaluated in the following aspects:

[0264] - Conversion activity, via the weighted average temperature, or WABT (weighted average bed temperature) (Table 3), of the combined hydrocracking sections 1 and 2 required to achieve a total conversion of 86% of the 370 °C+ fraction,

[0265] - Yield of kerosene 150 - 280 °C (Table 2).

[0266] - And cold flow properties (via the crystal disappearance point of kerosene and the cloud point of gas oil) (Table 2).

[0267] The yields of the main products given in Table 2 are calculated relative to the liquid feedstock, i.e., the mixture containing 83 wt% of vacuum gas oil and 17 wt% of animal fat before the hydrotreating step. It should be noted that the sum of the yields given in Table 3 is less than 100% (but 98.7%) because the yields of by-products (H2S, NH3, CO, CO2, and water) and hydrogen consumption are not reported in Table 3 as they are produced during the hydrotreating step, which is the same for all the compared systems, and thus there is no difference between the systems.

[0268] Characteristics of the mixture of vacuum gas oil and animal fat

[0269] Table 2

[0270]

[0271] "SD" is simulated distillation.

[0272] Operating conditions and performance of the methods of Examples 7 - 12

[0273] Table 3

[0274] Table 3

[0275]

[0276] In Example 9 according to the present invention, the use of a sequence of a catalyst comprising USY zeolite and β - zeolite, followed by a catalyst comprising β - zeolite with SAR = 250, compared with Example 7 where only one hydrocracking catalyst comprising USY zeolite and β - zeolite is used throughout the catalytic zone, enables an improvement in the low - temperature properties of the kerosene and diesel fractions (the crystal disappearance point of the kerosene fraction and the cloud point of the gas oil fraction are reduced by 5 °C and 9 °C respectively) and an improvement in the kerosene yield (+0.1%).

[0277] In Example 10 according to the present invention, the use of a sequence of a catalyst comprising a single USY zeolite, followed by a catalyst comprising β - zeolite with SAR = 250, compared with Example 8 where only one hydrocracking catalyst USY is used throughout the catalytic zone, enables an improvement in the low - temperature properties of the kerosene and diesel fractions (the crystal disappearance point of the kerosene fraction and the cloud point of the gas oil fraction are reduced by 7 °C and 10 °C respectively) and an improvement in the kerosene yield (+0.2%).

[0278] In Example 11 (according to the present invention), the sequence of a supported hydrocracking catalyst comprising a mixture of USY zeolite and β - zeolite, followed by a supported catalyst comprising β - zeolite with SAR equal to 24 (according to the present invention) enables simultaneous improvement in the low - temperature properties of diesel and kerosene (in Example 11 according to the present invention, the crystal disappearance point of the kerosene fraction and the cloud point of the gas oil fraction are reduced by 4 °C and 8 °C respectively), and maximizes the kerosene yield compared with Example 7 (+1.3%).

[0279] In Example 12 (according to the present invention), the sequence of a supported hydrocracking catalyst comprising a single USY zeolite, followed by a catalyst supported on β - zeolite with an Si / Al ratio of 24 enables an increase in the kerosene yield compared with Example 8 (+0.6%). Similarly, compared with Example 8, the low - temperature properties of kerosene and diesel are also improved (the crystal disappearance point of the kerosene fraction and the cloud point of the gas oil fraction are reduced by 4 °C and 8 °C respectively), showing that the present invention also works with a first catalyst consisting only of USY without β.

Claims

1. A process for producing middle distillates from at least one fossil hydrocarbon feedstock, at least 50% by weight of the compounds of which have an initial boiling point greater than 250 °C and a final boiling point less than 800 °C, said fossil hydrocarbon feedstock being co-processed with at least one renewable feedstock selected from vegetable oils, algal oils, edible oils and animal fats, which may be fresh or used, alone or in admixture, and feedstocks obtained from the reprocessing of biomass / plastics / tyres / and domestic waste, alone or in admixture, said process comprising the step of hydrotreating the feedstock mixture in the presence of hydrogen and at least one hydrotreating catalyst and the step of hydrocracking at least a part and preferably all of the hydrotreated feedstock, said hydrocracking step being carried out at a temperature of 200 °C to 480 °C, at a total pressure of 1 MPa to 25 MPa at a hydrogen gas volume to hydrocarbon feedstock volume ratio of 80 to 5000 litres / litre and at a space velocity (HSV) defined by the ratio of the volume flow rate of the liquid hydrocarbon feedstock to the volume of catalyst charged to the reactor of 0.1 to 50 h -1 and the step of hydrocracking the hydrotreated feedstock comprises at least: a) a step of contacting at least a part, and preferably all, of the hydrotreated feedstock with at least one first catalyst in a first catalytic zone, the first catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprising at least one zeolite having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR) and at least one binder, b) then contacting all the effluents from step a) with a second catalyst in a second catalytic zone without an intermediate separation step between the first catalytic zone and the second catalytic zone, the second catalyst comprising at least one metal from Group VIB of the Periodic Table and / or at least one metal from Group VIII of the Periodic Table and a support, the support comprising at least one zeolite with a BEA structure code and at least one binder.

2. The method according to claim 1, wherein the hydrocarbon feedstock is selected from light gas oil from a fluid catalytic cracking unit, atmospheric distillate, vacuum distillate from direct distillation of crude oil or from a conversion unit such as an FCC, coking, H - oil or visbreaking unit, feedstock from a unit for extracting aromatics from a lubricating oil base stock or solvent dewaxing of a lubricating oil base stock, distillate oil from a fixed - bed or fluid - bed desulfurization or hydroconversion process of ATR (atmospheric residue) and / or VR (vacuum residue) and / or deasphalted oil.

3. The method according to any one of claims 1 and 2, wherein the vegetable oil is crude or fully or partially refined and is obtained from the following plants: rapeseed, sunflower, soybean, palm, palm kernel, olive, coconut, jatropha, and the animal fat is selected from the residues from the food industry or lard or fat from the catering industry.

4. The method according to any one of the preceding claims, wherein the zeolite used in the support of the first catalyst is selected from zeolites of the FAU, BEA, ISV, IWR, IWW, MEI and UWY structure types, either alone or in admixture, and is preferably selected from zeolites of the FAU and BEA structure types, either alone or in admixture.

5. The method according to claim 4, wherein the zeolite used in the support of the first catalyst is selected from Y zeolite and β zeolite, either alone or in admixture, and preferably the zeolite is Y zeolite, and very preferably is dealuminated USY zeolite.

6. The method as claimed in claim 5, wherein the Y zeolite used in the support of the first catalyst has an initial lattice parameter a0 of the unit cell that is less than preferably less than and preferably less than and still more preferably less than .

7. The method according to any one of the preceding claims, wherein the zeolite with a BEA structure code used in the support of the second catalyst is preferably a β zeolite having an SiO2 / Al2O3 molar ratio or SAR of 10 to 300, preferably 10 to 100, preferably 10 to 50, preferably 10 to 30, more preferably 10 to 25, still more preferably 12 to 24 and still more preferably 15 to 24.

8. The process as claimed in claim 7, wherein the second catalyst used in step b) may contain at least one other zeolite selected from zeolites having at least a series of channels whose openings are defined by rings of 12 oxygen atoms (12MR), preferably selected from zeolites of the FAU, BEA, ISV, IWR, IWW, MEI, UWY, MFI and MTW structure types alone or in admixture or zeolite IZM-2, and preferably selected from zeolites of the FAU and BEA structure types alone or in admixture.

9. The process as claimed in any one of the preceding claims, wherein the volume fraction of the first catalyst used in step a) of the hydrocracking step, relative to the total of the two catalysts used in steps a) and b), is preferably from 50% to 95% by volume, and preferably from 60% to 95% by volume, very preferably from 65% to 90% by volume, and still more preferably from 65% to 85% by volume.

10. The process as claimed in any one of the preceding claims, wherein the volume fraction of the second catalyst used in step b) relative to the total of the two catalysts used in steps a) and b) is from 5% to 50% by volume, and preferably from 5% to 40% by volume, very preferably from 10% to 35% by volume, and still more preferably from 15% to 35% by volume.

11. The process as claimed in any one of the preceding claims, wherein the effluent from step b) of the hydrocracking step is sent to a fractionation column to recover at least one middle distillate fraction and at least one heavy fraction containing unconverted compounds, and the said heavy fraction is sent to a second hydrocracking step in the presence of hydrogen and a hydrocracking catalyst or to a hydrotreating step a).

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