Process for processing feedstocks from renewable sources to produce bio-based olefins

Abstract

The present invention relates to a process for treating a feedstock comprising triglycerides and / or fatty acids and / or esters from renewable sources, said process comprising the following steps: a) a step of hydrotreating said feedstock in the presence of hydrogen and at least one fixed bed hydrotreating catalyst, the invention relates to a method for hydroprocessing a hydroprocessing effluent, which is carried out at a temperature of between 280 DEG C and 410 DEG C, and at a relative pressure of between 2.0 and 13.0 MPa, and at an hourly space velocity of between 0.3 and 5 h <-1 >, and which obtains a hydroprocessing effluent; b) a step of hydrocracking the hydrotreated effluent obtained in step a) at a temperature of between 280 DEG C and 410 DEG C in the presence of hydrogen and at least one fixed bed hydrocracking catalyst, carried out at a pressure of between 2.0 MPa and 13.0 MPa and at an hourly space velocity of between 0.5 and 10 h <-1 >, and obtaining a hydrocracked effluent; c) a step of separating the hydrocracking effluent obtained in step b) and obtaining at least one gaseous effluent comprising hydrogen and a hydrocarbon-based liquid effluent; d) a step of stripping the hydrocarbon-based liquid effluent obtained in step c) and obtaining at least one exhaust gas fraction and a stripped liquid effluent; e) a step of fractionating the stripped liquid effluent obtained in step d) and obtaining at least one paraffin-rich naphtha fraction; f) a step of steam cracking at least part, preferably all, of the naphtha fraction obtained in step e) and obtaining at least one bio-based gaseous effluent comprising ethylene and propylene.

Description

TECHNICAL FIELD

[0001] The present invention relates to a process for treating a feedstock containing triglycerides and / or fatty acids and / or esters from renewable sources to selectively produce naphtha, which is capable of producing olefins such as ethylene, propylene and biopolymers for the chemical industry. PRIOR ART

[0002] Many processes have been developed for hydrotreating feedstocks containing triglycerides and / or fatty acids and / or esters from renewable sources to increase the proportion of renewable fuels in fossil fuels.

[0003] For example, FR2917424 discloses a process for treating a feedstock from renewable sources, which comprises a hydrotreating step in the presence of at least one fixed bed catalyst, said catalyst comprising a hydrodehydrogenation functionality and an amorphous support, then separating hydrogen, gases and at least one hydrocarbonaceous liquid effluent consisting of at least 50% linear n-alkanes from the hydrotreating effluent from step a), and steam cracking at least a portion of the hydrocarbonaceous liquid effluent from the separation step b).

[0004] FR3104603 discloses a process for isomerizing an alkane feedstock, said alkane feedstock preferably from hydrotreated vegetable and / or animal oils or from low-temperature Fischer-Tropsch synthesis, said process using a bifunctional catalyst comprising at least one metal of Group VIII of the Periodic Table, at least one matrix and at least one zeolite IZM-2. This process is capable of improving the selectivity for the production of middle distillate bases by limiting the production of light cracking products that cannot be incorporated into the gas oil and / or kerosene pool.

[0005] However, it is also necessary to increase the production of bio-based olefins obtained by steam cracking of feedstocks containing triglycerides and / or fatty acids and / or esters from renewable sources in order to increase the amount of sustainable polymers produced to replace polymers from fossil sources.

[0006] US2014350314 specifically discloses a process which comprises a step of hydrotreating a renewable feedstock to produce a hydrocarbonaceous effluent, a step of hydrocracking said hydrocarbonaceous effluent to produce a certain distribution of cracked hydrocarbons, a step of separating a heavy fraction and a bio-based naphtha fraction, and a step of obtaining a middle distillate fraction derived from the heavy fraction.

[0007] Surprisingly, the applicant has developed an improved process for enabling the production of a naphtha fraction from a bio-based feedstock, which can be co-processed in most liquid steam crackers with a minimum number of steps. SUMMARY OF THE INVENTION The present invention relates to a method for treating a feedstock containing triglycerides and / or fatty acids and / or esters from renewable sources, the method comprising the following steps: a) a step of hydrotreating the feedstock in the presence of hydrogen and at least one fixed-bed hydrotreating catalyst, which is carried out at a temperature between 280 °C and 410 °C, and at a relative pressure between 2.0 and 13.0 MPa, and at a space velocity between 0.3 and 5 h -1 and obtaining a hydrotreated effluent; b) a step of hydrocracking the hydrotreated effluent obtained in step a) in the presence of hydrogen and at least one fixed-bed hydrocracking catalyst at a temperature between 280 °C and 410 °C, which is carried out at a pressure between 2.0 MPa and 13.0 MPa and at a space velocity between 0.5 and 10 h -1 and obtaining a hydrocracked effluent; c) a step of separating the hydrocracked effluent obtained in step b) and obtaining at least one gaseous effluent containing hydrogen and a hydrocarbon-based liquid effluent; d) a step of stripping the hydrocarbon-based liquid effluent obtained in step c) and obtaining at least one exhaust fraction and a stripped liquid effluent; e) a step of fractionating the stripped liquid effluent obtained in step d) and obtaining at least one paraffin-rich naphtha fraction; f) a step of steam cracking at least a part, preferably all, of the naphtha fraction obtained in step e) and obtaining at least one bio-based gaseous effluent containing ethylene and propylene.

[0009] The method according to the invention enables the production of ethylene, propylene and polymerized bio-based polymers.

[0010] Advantageously, this solution enables the production of only upgradable fractions in a liquid steam cracker receiving the naphtha fraction and possibly the LPG fraction.

[0011] Thus, the method according to the invention preferably does not produce any distillate fraction.

[0012] Furthermore, the method is efficient because it does not require any strict separation of the hydrotreated effluent between step a) and step b), and only requires a container to generate the liquid effluent of the hydrotreating to be partially sent to step a) to control the exothermicity of the reaction.

[0013] In one embodiment, the hydrotreating step a) is carried out at a hydrogen-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 between.

[0014] In one embodiment, the at least one hydrotreating catalyst comprises a support and an active phase, the active phase comprising at least one Group 6 metal and optionally one or more Group 9 or 10 metals, and the active phase preferably contains only molybdenum (Mo), or nickel and molybdenum (NiMo), or cobalt and molybdenum (CoMo), or cobalt, nickel and molybdenum (CoNiMo).

[0015] In one embodiment, after the hydrotreating step a), there is a step of separating the hydrotreating effluent at a high temperature between 150 °C and 410 °C and at a high pressure between 2.0 and 13.0 MPa to obtain at least one gaseous effluent and one liquid effluent.

[0016] In one embodiment, a portion of the liquid effluent obtained in the high-temperature separation step is recycled to the hydrotreating step a).

[0017] In one embodiment, the hydrocracking step b) is carried out at a hydrogen-to-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 therebetween.

[0018] In one embodiment, the hydrocracking step b) is carried out at a minimum hydrogen partial pressure of 2.5 MPa.

[0019] In one embodiment, the at least one hydrocracking catalyst comprises a hydrogenation functionality and an acid functionality provided by a support having a large surface area with surface acidity, such as halogenated alumina, a combination of boron and aluminum oxides, amorphous silica-alumina, and zeolites Y, β, and ZSM-5.

[0020] In one embodiment, in step b), the single-pass conversion of the converted hydrocarbon-based compounds is between 20 wt% and 100 wt%.

[0021] In one embodiment, after the separation step c), there is a step of purifying and / or washing the gaseous effluent containing hydrogen obtained in step c) to remove contaminants, especially H2S, CO, and CO2, and then recycling the washed gaseous effluent to at least the hydrotreating step a) and / or the hydrocracking step b).

[0022] In one embodiment, a portion of the liquid effluent obtained in step c) is recycled to step a) and / or step b), preferably to step a).

[0023] In one embodiment, the off-gas fraction obtained in step d) is sent to a separation step to recover a depropanized gaseous off-gas fraction and an LPG fraction with low propane and butane contents.

[0024] In one embodiment, the LPG fraction is sent, either alone or as a mixture with the naphtha fraction obtained in step e), to the steam cracking step f) and into one or more furnaces of the steam cracking step f).

[0025] In one embodiment, in step e) of fractionating the stripped liquid effluent obtained in step d), a heavy fraction is also obtained which contains hydrocarbon compounds having a boiling point above 150°C, preferably above 175°C.

[0026] In one embodiment, all or part of the heavy fraction obtained in step e) is recycled to the hydrotreating step a) and / or the hydrocracking step b), preferably at a recycle feedstock / fresh feedstock ratio between 0 and 4. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 Illustrates the implementation of the method according to the first embodiment of the present invention.

[0028] Figure 2 Illustrates the implementation of the method according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the expressions "of between... and..." and "between... and..." are equivalent and mean that the limit values of the interval are included within the described numerical range. If this is not the case and if the limit values are not included within the described range, the present invention will give such an indication.

[0030] Within the meaning of the present invention, the various parameter ranges of a given step, such as a pressure range and a temperature range, can be used alone or in combination. For example, within the meaning of the present invention, a range of preferred pressure values can be combined with a range of more preferred temperature values.

[0031] In the following, specific embodiments of the present invention may be described. When technically feasible, they can be implemented alone or together without limitation on the combination.

[0032] In the present specification, the term "Cx hydrocarbon" means a hydrocarbon compound containing x carbon atoms. The term "Cx+ hydrocarbon" means a hydrocarbon compound having at least x carbon atoms. The term "Cx to Cy hydrocarbon" means a hydrocarbon compound having x to y carbon atoms.

[0033] Throughout the text, the groups of chemical elements are described according to the new IUPAC classification. For example, Group 9 or 10 corresponds to the metals in columns 9 and 10 according to the IUPAC classification or to the last two columns of Group VIIIB according to the CAS classification (CRC Handbook of Chemistry and Physics, CRC editor press, chief editor D.R. Lide, 81st edition, 2000 - 2001). Similarly, Group 6 corresponds to the metals in column 6 according to the IUPAC classification or to the metals in column VIB according to the CAS classification.

[0034] "Fresh feedstock" is understood to mean the feedstock to be treated that enters the process in the hydrotreating step a).

[0035] "Naphtha fraction" is understood to mean the fraction with a boiling point between the boiling point of hydrocarbon compounds having 5 carbon atoms per molecule and 215 °C.

[0036] "Purge" is understood to mean the fraction containing unreacted compounds that is produced continuously or discontinuously to avoid the accumulation of unwanted and non-crackable heavy molecules.

[0037] "Exhaust fraction" is understood to mean the vapor fraction from the stripping step.

[0038] "Depropanized exhaust fraction" is understood to mean the vapor fraction with a low propane and butane content. "Low content" is understood here to mean: containing less than 2 vol%, preferably less than 1 vol% of propane and butane compounds.

[0039] "LPG fraction" is understood to mean the vapor fraction rich in propane and butane, similar to the fossil liquefied petroleum gas LPG fraction containing these compounds. "Rich" is understood here to mean: containing more than 95 vol% of propane and butane compounds.

[0040] "Light naphtha" is understood to mean the fraction with a boiling point between the boiling point of hydrocarbon compounds having 5 carbon atoms per molecule and 110 °C.

[0041] For the naphtha in step e), "alkane-rich" is understood to mean: containing more than 90 wt% of the required compounds.

[0042] "Distillate" is understood to mean the fraction characterized by a distillation range and having a boiling point greater than 150 °C to 560 °C.

[0043] "Pyrolysis oil" is understood to mean the fraction recovered at the bottom of the primary fractionation column in the steam cracking step.

[0044] In the present text, hydrotreating includes the hydrotreating reaction of impurities using at least one catalyst in the presence of hydrogen, in particular hydrodeoxygenation, hydrodesulfurization, hydrodenitrogenation, olefin hydrogenation, etc., to produce an impurity-depleted effluent.

[0045] In the present text, "hydrocracking" includes a process aimed at reducing the carbon number of molecules and producing a product with a distillation point lower than that of the feedstock using at least one catalyst in the presence of hydrogen.

[0046] In the present text, "stripping" includes a physical separation method in which one or more components are removed from a liquid stream by a vapor stream or heat supply. The "stripped" effluent is thus the liquid effluent leaving the stripping step.

[0047] Feedstock The method according to the invention consists in converting a wide range of feedstocks of renewable origin, essentially composed of triglycerides and fatty acids, into alkanes.

[0048] "Essentially composed of triglycerides and fatty acids" is understood to mean a feedstock containing at least 70% by weight, preferably at least 80% by weight, of triglycerides and fatty acids. Other specific elements may be present, but only those that do not substantially affect the basic characteristics of the composition.

[0049] These feedstocks are generally characterized by a high molar mass (most commonly greater than 800 g / mol), and the fatty acid chains constituting them advantageously have a carbon atom number between 4 and 24 and usually an unsaturation number per chain between 0 and 3, where higher values can be reached for certain specific feedstocks. Among the feedstocks that can be converted by the method according to the invention, mention may be made (this list is not exhaustive): vegetable oils such as rapeseed oil, jatropha oil, soybean oil, palm oil, sunflower oil, olive oil, coconut oil, camelina oil, fish oil or heterotrophic or autotrophic algal oils, or animal fats such as tallow, or residues from the paper industry (such as tall oil), or mixtures of these various feedstocks.

[0050] Preferably, the feedstock of renewable origin is selected from oils and fats of plant or animal origin containing triglycerides and / or free fatty acids and / or esters, or mixtures of such feedstocks.

[0051] All these feedstocks contain a high oxygen content, i.e., generally greater than 5% by weight, preferably greater than 8% by weight, and significant amounts of impurities that may contain at least one heteroatom other than oxygen and organic impurities substantially containing nitrogen at very variable contents depending on the feedstock source. The feedstocks may generally contain compounds having heteroatoms other than oxygen in amounts between 0.1 and 2500 ppm. The contents of nitrogen and sulfur are generally less than 100 ppm by weight; for certain feedstocks, they may reach 1% by weight.

[0052] The feedstocks generally have an oxygen content of at most 20% by weight, preferably at most 15% by weight, preferably between 5% and 15% by weight, especially between 8% and 15% by weight. The feedstocks are different from immiscible bio-oil type feedstocks.

[0053] The feedstock from renewable sources used in the process according to the invention can advantageously be unrefined or can have undergone at least one step known to those skilled in the art for refining edible oils, such as a degumming or dephosphatation step. The feedstock that has undergone at least said refining step is called semi-refined and still contains at most 20 ppm of phosphorus, calcium, magnesium, iron, and / or zinc in the form of phospholipids at the end of such treatment.

[0054] In one embodiment, the presence of feedstocks of fossil origin is excluded to produce only fractions of renewable origin for the steam cracking step.

[0055] Advantageously, the fresh feedstock is selected from vegetable oils such as rapeseed oil, jatropha oil, soybean oil, palm oil, sunflower oil, olive oil, coconut oil, camelina oil, fish oil or heterotrophic or autotrophic algal oils, or animal fats such as tallow, or residues from the paper industry (such as tall oil), or mixtures of these various feedstocks.

[0056] Operating conditions and catalysts Hydrotreating step a) The process according to the invention comprises a step a) of hydrotreating the feedstock in the presence of hydrogen and at least one fixed bed hydrotreating catalyst, which is carried out at a temperature between 280 °C and 410 °C, preferably between 290 °C and 320 °C, and at a relative pressure between 2.0 and 13.0 MPa, preferably between 2.5 and 9.0 MPa, and at a space velocity (HSV) between 0.3 and 5 h -1 between, preferably between 0.7 and 3 h -1 between, and a hydrotreated effluent is obtained.

[0057] In one embodiment, the hydrotreating catalyst contains conventional hydrogenation functionalities.

[0058] Advantageously, the hydrotreating catalyst comprises a support and an active phase, the active phase comprising at least one Group 6 metal and optionally one or more Group 9 or 10 metals, and the active phase preferably contains only molybdenum (Mo), or nickel and molybdenum (NiMo), or cobalt and molybdenum (CoMo), or nickel, cobalt and molybdenum (CoNiMo).

[0059] Advantageously, catalysts can be used, for example, which comprise 0.5% to 10% by weight of nickel (expressed as nickel oxide NiO) or 1% to 30% by weight of molybdenum, preferably 5% to 25% by weight of molybdenum (expressed as molybdenum trioxide MoO3), on an alumina support. The total content of oxides of Group 6 and Group 9 or 10 metals in the catalyst is generally between 5% and 40% by weight, and preferably between 7% and 35% by weight. Where appropriate, the weight ratio of (one or more) Group 6 metals to (one or more) Group 9 or 10 metals (expressed on the basis of the metal oxides) is generally from about 20 to about 1, and most commonly from about 10 to about 2.

[0060] Advantageously, the various catalysts mentioned above can also be stacked in successive layers. The stack can be, for example, a sequence of a layer containing nickel, cobalt and molybdenum (CoNiMo), then a layer containing nickel and molybdenum (NiMo), or vice versa. Another stack can be, for example, a sequence of a layer containing cobalt and molybdenum (CoMo), then a layer containing nickel and molybdenum (NiMo), or vice versa.

[0061] Advantageously, the hydrotreating catalyst is at least partially or even completely supported on an alumina support.

[0062] In one embodiment, the hydrotreating step a) is carried out at a hydrogen-to-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 and preferably between 150 and 1000 Nm 3 / Sm 3 .

[0063] The hydrogen-to-hydrocarbon ratio is herein defined as the ratio of the volume flow rate of hydrogen measured under normal temperature and pressure conditions to the volume flow rate of the feedstock introduced into step a) (in standard m 3 (denoted as Nm 3 ) of H2 / standard m 3 (denoted as Sm 3 ) of the feedstock introduced into step a)).

[0064] In one embodiment, the hydrotreating step a) is carried out at a minimum hydrogen partial pressure of 2.0 MPa, preferably at least 4.0 MPa.

[0065] This hydrotreating step a) advantageously enables the production of a hydrocarbon fraction having a reduced content of oxygen and nitrogen compounds.

[0066] In one embodiment, an optional step of separating the hydrotreating effluent is carried out at a high temperature between 280 °C and 410 °C, preferably between 290 °C and 320 °C, after the hydrotreating step a), and at least one gaseous effluent rich in hydrogen, oxygenates and light hydrocarbons and a liquid effluent are obtained. "Rich in hydrogen" is understood herein to mean a hydrogen content of greater than 65% by volume.

[0067] In one embodiment, a portion of the liquid effluent obtained in the optional high-temperature separation step is recycled to the hydrotreating step a). This recycling advantageously enables the control of the temperature increase caused by the hydrotreating reaction.

[0068] The non-recycled portion of the liquid effluent from step a) and the gaseous effluent rich in hydrogen are fed to the next hydrocracking step b).

[0069] In one embodiment, a portion of the liquid effluent obtained in the optional high-temperature separation step is recycled to the hydrotreating step a) such that the mass ratio of the recycled portion of the effluent to the fresh feedstock introduced into the hydrotreating step a) is less than 3, preferably less than 1.

[0070] Advantageously, the configuration of the reactor capable of carrying out the reaction according to the invention consists of a plurality of suitable catalyst beds. Generally, this configuration has at least 2 catalyst beds, and preferably more than 3, and in particular more than 4 beds, but less than 20 beds, and preferably less than 15 beds, and in particular less than 10 catalyst beds. The preferred configuration includes 3 to 19 beds, and particularly includes 4 to 9 catalyst beds.

[0071] The liquid effluent of step a) consists essentially of straight-chain alkanes, i.e., the product has a composition of at least 90% by weight of straight-chain alkanes.

[0072] Hydrocracking step b) The process according to the invention comprises a step b) of hydrocracking the hydrotreating effluent obtained in step a) in the presence of hydrogen and at least one fixed-bed hydrocracking catalyst at a temperature between 280 °C and 410 °C, preferably between 290 °C and 320 °C, at a pressure between 2.0 MPa and 13.0 MPa, preferably between 2.5 and 9.0 MPa, and at a HSV between 0.5 and 10 h -1 between, preferably between 1 and 4 h -1 between, and a hydrocracked effluent is obtained.

[0073] In the process according to the invention, the hydrocracking step is carried out immediately after the hydrotreating step, optionally with an intermediate separation step at high temperature and high pressure, in order to minimize pressure and temperature losses with the minimum number of equipment items. "High temperature" is understood to mean a temperature between 150 °C and 410 °C, preferably between 200 °C and 320 °C. "High pressure" is understood to mean a relative pressure between 2.0 and 13.0 MPa, preferably between 2.5 and 9.0 MPa, especially at a pressure slightly lower than the pressure of step a) and slightly higher than the pressure of step b), taking into account the pressure losses associated with the continuous equipment items.

[0074] In an embodiment where a high-temperature separation step is carried out after the hydrotreating step a), the non-recycled part of the liquid effluent and the hydrogen-rich gaseous effluent are hydrocracked in step b).

[0075] In one embodiment, the hydrocracking step b) is carried out at a hydrogen-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 preferably between 200 and 2000 Nm 3 / Sm 3 between.

[0076] Advantageously, in step b), the single-pass conversion to hydrocarbonaceous compounds is between 20 wt% and 100 wt%, preferably between 45 wt% and 80 wt%, preferably between 50 wt% and 70 wt%. The single-pass conversion is calculated using the following operation relative to the feedstock entering step b): (weight flow rate of the effluent entering step b minus the weight flow rate of the optional bottom fraction from the fractionation in step e)) divided by the weight flow rate of the effluent entering step b). Thus, the hydrocracking step b) enables the advantageous production of naphtha and the amount of LPG produced is minimized.

[0077] Advantageously, the total conversion of fresh feedstock to naphtha is between 80% and 100%, preferably between 95% and 100%, more preferably between 99% and 100%, especially 100%. The total conversion is calculated using the following operation relative to the feedstock entering step a): (weight flow rate of the fresh feedstock entering step a minus the weight flow rate of the purge fraction of the heavy distillate in step e below) divided by the weight flow rate of the fresh feedstock entering step a).

[0078] In one embodiment, the hydrocracking step b) is carried out at a minimum hydrogen partial pressure of 2.5 MPa.

[0079] The operating conditions of the hydrocracking step b) are advantageously adjusted to maximize the production of naphtha while ensuring good operability of the hydrocracking unit. The operating conditions used in the (one or more) reaction zones are generally expressed using the weighted average bed temperature (WABT). The hydrocracking temperature is advantageously determined according to the catalytic system, the equipment used and its configuration. For example, the weighted average bed temperature (or WABT) is calculated as follows: where T inlet : the temperature at the inlet of the catalyst bed in the hydrocracking reaction section, and T outlet : the effluent temperature at the outlet of the catalyst bed in the hydrocracking reaction section.

[0080] The hourly space velocity (HSV) is hereby defined as the ratio of the hourly volume flow rate of the hydrocarbon fraction fed to step b) to the volume of the (one or more) catalysts.

[0081] Advantageously, the hydrogen used in the hydrocracking step b) can be sourced from a hydrogen supply and / or from recycled hydrogen, particularly from the separation step c), preferably after purification, and / or from the hydrogen-rich gaseous effluent resulting from step a).

[0082] The at least one hydrocracking catalyst should advantageously be a bifunctional catalyst, which has a hydrogenation phase to be able to hydrogenate impurities and achieve an equilibrium between saturated compounds and the corresponding olefins, and an acidic phase to be able to promote hydroisomerization and hydrocracking reactions. The acidic functionality is provided by a support with a large surface area having surface acidity (generally 100 to 800 m 2 .g -1 ), such as halogenated (especially chlorinated or fluorinated) alumina, a combination of boron and aluminum oxides, amorphous silica-alumina and zeolites Y, β and ZSM-5. The hydrogenation functionality is provided by one or more metals from columns 9 and 10 of the periodic table such as cobalt, nickel, rhodium, palladium, iridium and platinum, or by a combination of at least one metal from column 6 of the periodic table such as molybdenum and tungsten and at least one metal from columns 9 and 10. The applicant has also developed a series of catalysts that can be used in the hydrocracking step b); these catalysts are particularly described in the documents FR2819430, FR2846574, FR2875417, FR2863913, FR2795341, FR2795342 and FR2984760.

[0083] Advantageously, a catalyst can be used which, for example, contains from 0.5% to 10% by weight of nickel (expressed as nickel oxide NiO) or from 1% to 30% by weight of molybdenum, preferably from 5% to 25% by weight of molybdenum (expressed as molybdenum trioxide MoO3) or from 1% to 40% by weight of tungsten (expressed as tungsten trioxide WO3) on the support concerned. The total content of oxides of Group 6 and Group 9 or Group 10 metals in the catalyst is generally between 5% and 40% by weight, and preferably between 7% and 35% by weight. Where appropriate, the weight ratio of (one or more) Group 6 metals to (one or more) Group 9 or Group 10 metals (expressed on the basis of the metal oxides) is generally from about 20 to about 1, and most commonly from about 10 to about 2.

[0084] In one embodiment, commercial catalysts can be used, in addition and depending on the characteristics of the feedstock and the desired performance qualities, such as, for example, HDK776, HDK766, HYK732, HYK752, HYK762, HYK742, HYK 743 sold by AXENS.

[0085] In the case where the catalyst contains zeolite, the zeolite content in the (one or more) hydrocracking catalysts is advantageously between 0.1% and 80% by weight, preferably between 3% and 70% by weight, the percentages being expressed as the zeolite relative to the total weight of the catalyst.

[0086] Preferred catalysts comprise at least one metal of Column 6 and optionally at least one non-noble metal of Columns 9 and 10, at least one promoter element, preferably phosphorus, at least one zeolite Y and at least one alumina binder, and preferably consist of these.

[0087] Even more preferred catalysts comprise nickel, molybdenum, phosphorus, zeolite USY and optionally zeolite β and alumina, and preferably consist of these.

[0088] Another preferred catalyst comprises nickel, tungsten, alumina and silica-alumina, and preferably consists of these.

[0089] Another preferred catalyst comprises nickel, tungsten, zeolite USY, alumina and silica-alumina, and preferably consists of these.

[0090] In a particular embodiment, the hydrocracking catalyst is in extruded form.

[0091] According to another aspect of the present invention, the hydrocracking catalyst as described above further comprises one or more oxygen- and / or nitrogen- and / or sulfur-containing organic compounds. Such catalysts are generally denoted by the term "additivated catalyst". Generally, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, and amide functional groups, or compounds including a furan ring or sugars.

[0092] According to one embodiment, this hydrocracking step b) enables the production of a naphtha-type fraction that advantageously has a very high paraffin content, with a paraffin content generally greater than 90% by weight, preferably greater than 95% by weight.

[0093] Preferably, the naphtha produced in step b) consists of paraffin compounds contained in the feedstock and any other non-paraffin compounds.

[0094] Advantageously, the configuration of the reactor capable of carrying out the reaction according to the present invention consists of a plurality of suitable catalyst beds. Generally, this configuration includes at least 2 catalyst beds, and preferably more than 3, and especially more than 5 beds, but less than 20 beds, and preferably less than 15 beds, and especially less than 10 catalyst beds. A preferred configuration includes 2 to 19 beds, and especially 3 to 9 catalyst beds.

[0095] Separation step c) The method according to the present invention includes a step c) of separating the hydrocracking effluent obtained in step b) and obtaining at least one gaseous effluent containing hydrogen and a hydrocarbon-based liquid effluent.

[0096] In one embodiment, in step c) of separating the hydrocracking effluent obtained in step b), pollutants, any light hydrocarbons, and an aqueous liquid effluent are also obtained.

[0097] The separation section of step c) is advantageously carried out in separation equipment known to those skilled in the art (separation vessels, pumps, heat exchangers, etc. that can operate at various pressures and temperatures).

[0098] In one embodiment, after the separation step c), the gaseous effluent containing hydrogen obtained in step c) is purified and / or washed to remove pollutants, especially H2S, CO, and CO2, and then the washed gaseous effluent is recycled to at least the hydrotreating step a) and / or the hydrocracking step b). The objective of this step is to ensure hydrogen coverage and exothermicity control in step a) and / or step b).

[0099] Typically, a small portion of the gaseous effluent can be optionally purged to avoid the accumulation of oxygenates and light compounds in the fuel gas network or hydrogen recovery unit.

[0100] In one embodiment, a portion of the liquid effluent obtained in step c) is recycled to step a) and / or step b), preferably to step a). In embodiments where step a) is followed by a high-temperature separation step and then a portion of the liquid effluent from this separation is recycled, recycling to step a) enables the management of exothermicity and a reduction in the flow rate of the first recycle. Recycling to step b) enables the control of the conversion in step b) and the total conversion of the fresh feedstock.

[0101] Stripping step d) The method according to the invention comprises a step d) of stripping the hydrocarbonaceous liquid effluent obtained in step c) and obtaining at least one off-gas fraction and a stripped liquid effluent.

[0102] Step d) particularly enables the removal of gases dissolved in the hydrocarbonaceous liquid effluent, such as ammonia, hydrogen sulfide, CO2, CO, and light hydrocarbons having 1 to 4 carbon atoms - by generating an off-gas fraction containing these compounds.

[0103] In one embodiment, the off-gas fraction, after an optional washing step, is sent, either alone or as a mixture with the naphtha fraction obtained in step e), in whole or in part, to a steam cracking step f), into one or more furnaces of the steam cracking step f), so as to enable the upgrading of this fraction into bio-based olefins.

[0104] In one embodiment, the off-gas fraction obtained in step d) is sent to a separation step to recover at least one depropanized gaseous off-gas fraction low in propane and butane and an LPG fraction. This separation step can advantageously be carried out in a separation column.

[0105] In one embodiment, the LPG fraction is sent, either alone or as a mixture with the naphtha fraction obtained in step e), to a steam cracking step f), into one or more furnaces of the steam cracking step f), so as to enable the upgrading of this fraction into bio-based olefins.

[0106] In one embodiment, the depropanized gaseous off-gas fraction low in propane and butane, after an optional washing step, is sent, either alone or as a mixture with the naphtha fraction obtained in step e), to a steam cracking step f), into one or more furnaces of the steam cracking step f), so as to enable the upgrading of this fraction into bio-based olefins.

[0107] In another embodiment, the depropanized gaseous off - gas fraction and / or LPG fraction with low propane and butane content are sent to a steam reforming step to obtain bio - based hydrogen.

[0108] According to one embodiment, step d) can be carried out in a section advantageously comprising at least one stripping column equipped with a reflux circuit including a reflux drum. Advantageously, the liquid effluent from step c) and a water vapor stream are supplied to the stripping column. The column can also be re - boiled by a furnace or an exchanger. The liquid effluent from step c) can optionally be heated before entering the stripping column.

[0109] Thus, the lightest compounds are entrained at the top of the column and enter the reflux circuit including the reflux drum, where gas / liquid separation takes place. The gas phase containing light hydrocarbons is taken out of the reflux drum as a gaseous stream. The stripped hydrocarbon - based liquid effluent is advantageously stabilized and taken out at the bottom of the stripping column.

[0110] According to one embodiment, the LPG liquid fraction can be recovered at the reflux drum and then stabilized in a stabilization column. The stabilized LPG liquid fraction is fed into the LPG fraction obtained in the step of separating the off - gas fraction.

[0111] According to one embodiment, the light naphtha fraction can be recovered at the reflux drum and then stabilized in a stabilization column. The stabilized light naphtha fraction is fed into the naphtha fraction obtained in fractionation step f).

[0112] According to one embodiment, a part of the hydrocarbon - based liquid effluent obtained in step c) is subjected to stripping step d), and another part is directly supplied to fractionation step d) so as to be able to obtain at least one off - gas fraction and the stripped liquid effluent sent to the fractionation step. In this embodiment, a part of the stripping step d) is carried out in the fractionation step.

[0113] According to another embodiment, the stripping step d) is integrated into fractionation step e), and a person skilled in the art can obtain the various streams described in these two steps using the same fractionation section including one or more columns.

[0114] Fractionation step e) The method according to the invention includes step e) of fractionating the stripped liquid effluent obtained in step d) and obtaining at least one paraffin - rich naphtha fraction.

[0115] In one embodiment, in step e) of fractionating the stripped liquid effluent obtained in step d), a heavy fraction containing hydrocarbon - based compounds with a boiling point higher than 150 °C, preferably higher than 175 °C, is also obtained.

[0116] In a particular embodiment, the resulting heavy fraction comprises compounds having a boiling point above 215 °C, preferably above 200 °C. This enables the production of a heavy naphtha fraction having a boiling point up to 215 °C.

[0117] In one embodiment, all or part of the heavy fraction is recycled to the hydrotreating step a) and / or the hydrocracking step b), preferably at a recycle feedstock / fresh feedstock ratio between 0 and 4. This enables the conversion in the hydrocracking reactor to be controlled and the overall conversion under optimal conditions to be achieved in terms of investment and utility consumption.

[0118] Advantageously, a small portion of the heavy fraction is bled continuously or intermittently before the heavy fraction is sent to steps a) and / or b). A person skilled in the art will adjust the bleed amount to remove compounds that cannot be cracked and have accumulated in the reaction circuit.

[0119] Advantageously, the amount of the recycled heavy fraction is adjusted such that the weight ratio of the recycle stream to the fresh feedstock fed into the overall process is less than or equal to 10, preferably less than or equal to 5, and preferably greater than or equal to 0.001, preferably greater than or equal to 0.01, and preferably greater than or equal to 0.1. Very preferably, the amount of the recycle stream is adjusted such that the weight ratio of the recycle stream to the fresh feedstock is between 0.2 and 5, preferably between 0.3 and 2.0, and even more preferably between 0.5 and 1.5.

[0120] Depending on the feedstock being processed, this recycling advantageously enables on the one hand the dilution of impurities and on the other hand the control of the temperature in the reaction steps a) and / or b), where the reactions involved may be highly exothermic.

[0121] The fractionation step advantageously includes at least one main fractionation column to enable the separation of the top fraction and the heavy fraction, which fractions contain the various products of these units.

[0122] The fractionation step e) is advantageously carried out at a pressure less than or equal to 1.0 MPa abs., preferably between 0.05 and 1.0 MPa abs.

[0123] In one embodiment, all fractions from the process are upgraded to renewable products.

[0124] The naphtha fraction is sent at least in part, preferably entirely, to the steam cracking unit f) to enable the upgrading of this fraction to bio-based olefins.

[0125] Advantageously, the naphtha yield in the process according to the invention is greater than 50% by weight, in particular greater than 60% by weight, preferably greater than 70% by weight, preferably between 50% by weight and 85% by weight. The naphtha yield is calculated relative to the fresh feed entering step a) using the following operation: (weight flow rate of the naphtha produced in step e) divided by the weight flow rate of the effluent entering step a)).

[0126] Steam cracking step f) The process according to the invention comprises a step f) of steam cracking at least a part, preferably all, of the naphtha fraction obtained in step e) and obtaining at least one bio-based gaseous effluent comprising ethylene and propylene.

[0127] In one embodiment, the off-gas fraction obtained in step d) is also treated in the steam cracking step f) - separately or jointly with the naphtha fraction.

[0128] In one embodiment, the LPG fraction obtained after an optional step of separating the off-gas fraction obtained in step d) is also treated in the steam cracking step f) - separately or jointly with the naphtha fraction.

[0129] In one embodiment, the depropanized gaseous off-gas fraction with a low propane and butane content obtained after an optional step of separating the off-gas fraction obtained in step d) is also treated in the steam cracking step f) - separately or jointly with the naphtha fraction.

[0130] The steam cracking step f) advantageously comprises the non-catalytic decomposition of saturated hydrocarbons from natural gas or naphtha in the presence of steam under the combined action of high temperature and low pressure in the presence of steam to produce unsaturated aliphatic or aromatic hydrocarbon fractions. These fractions are then used for the synthesis of a large number of products, such as polyethylene or propylene. In the case of the process according to the invention, the steam cracking step f) makes it possible to produce renewable (bio-derived) aliphatic unsaturated hydrocarbons.

[0131] Advantageously, the steam cracking step f) treats the naphtha fraction and / or the LPG fraction in suitable schemes and operating conditions known to those skilled in the art.

[0132] Advantageously, the steam cracking unit treats the naphtha fraction and / or the LPG fraction in the optional presence of an external naphtha and / or LPG feedstock.

[0133] Advantageously, the residence time in the steam cracking furnace is limited to limit the formation of heavy products. In addition, the effluent is quenched to fix the composition of the effluent at the outlet of the furnace.

[0134] Advantageously, the operating temperature of the steam cracking furnace depends on the nature of the feedstock. Preferably, the steam cracking furnace is suitable for processing feedstocks of the naphtha type.

[0135] In various variants of the process according to the invention, the feedstock in the steam cracking step may include an external feedstock, which corresponds to a dedicated furnace or a furnace common to the treatment of the feedstock produced by the steps of the process according to the invention. The said external feedstock can be quite diverse and ranges from light saturated hydrocarbons such as ethane, propane or ethane - propane mixtures to more or less heavy petroleum fractions such as petrochemical naphtha. The nature of the feedstock to be treated depends on the type of furnace installed.

[0136] Advantageously, the steam cracking step is carried out in a unit consisting of a certain number of furnaces, quench boilers and fractionation systems. The hydrocarbon - based feedstock enters the hot section of the unit via the convection zone A of the furnace (where it is preheated), and then it is mixed with steam also preheated in this same zone; the hydrocarbon and water then pass through the actual radiation zone of the furnace, where rapid heating and pyrolysis reactions occur. At the outlet of the furnace, in order to avoid any subsequent reaction, the kinetic evolution possibility of the effluent is fixed by quenching, which is usually carried out in two stages: a first indirect quench with water, followed by a direct quench using the by - products of the heavy residue pyrolysis. The effluent is then transferred to a primary fractionation column, which separates out at the bottom a heavy residue called "pyrolysis oil" and separates out the steam - cracked gasoline fraction and water by withdrawal, while the light pyrolysis products leave in gaseous form at the top.

[0137] After compression, washing with sodium hydroxide (aimed at removing H2S and acidic gases) and drying, these light effluents then enter the cold section of the unit, which can be designed in several ways but ensures the separation of hydrogen, 99.9% (by mass) of ethylene, 95% (by mass) of propylene (which can reach 99.5% (by mass) in whole or in part), the C4 fraction and the complementary fraction of steam - cracked gasoline rich in aromatics (more than 50 wt% of aromatic compounds).

[0138] Description of the Drawings Figure 1: Supply a vegetable oil feedstock 111 to a hydrotreating step a) in the presence of hydrogen 112 and at least one fixed bed catalyst, said catalyst comprising conventional NiMo hydrogenation functionality to obtain a hydrotreated vegetable oil effluent 113, which is then sent to a hydrocracking step b) in the presence of hydrogen 114 and in the presence of a zeolite USY NiMo type catalyst to obtain a hydrocracked effluent 115. Send the hydrocracked effluent 115 to a separation step c) to obtain a gaseous effluent 116 containing hydrogen and a liquid effluent 117. Send the liquid effluent 117 to a stripping step to recover an off-gas fraction 118 and a stripped liquid effluent 119. Then send the stripped liquid effluent 119 to a fractionation step e) to recover at least one paraffin-rich naphtha fraction 121. Send the naphtha fraction 121 to a steam cracking step f) to produce an effluent 122 rich in ethylene, propylene, and biobased light olefins. In this embodiment, the process does not produce any heavy fractions containing compounds with a boiling point higher than 150 °C.

[0139] Figure 2: Supply the vegetable oil feedstock 211 to a hydrotreating step a) in the presence of hydrogen 212 and at least one fixed bed catalyst, the catalyst comprising conventional NiMo hydrogenation functionality to obtain a hydrotreated vegetable oil effluent, and then immediately proceed to a high temperature separation step to recover a liquid effluent and a gaseous effluent 223 rich in hydrogen, oxygenates and light hydrocarbons. Recycle a portion of the liquid effluent 224 to the hydrotreating step a) to control and reduce the exotherm in the reactor during this step. Mix the non-recycled portion 213 of the liquid effluent with the gaseous effluent 223 and then send it to a hydrocracking step b) in the presence of the hydrogen contained in the gaseous effluent 223 and in the presence of a hydrogen-rich stream 214 and in the presence of a zeolite USY type hydrocracking catalyst to obtain a hydrocracked effluent 215. Send the hydrocracked effluent 215 to a separation step c) to obtain at least one gaseous effluent 216 containing hydrogen and a liquid effluent. Optionally send the gaseous effluent 216 to a washing step to remove contaminants and recycle it to the hydrotreating step a) and / or the hydrocracking step b). Optionally recycle a portion 225 of the liquid effluent to the hydrotreating step a) and / or the hydrocracking step b) to control and reduce the exotherm in the reactors of these steps. Send the non-recycled portion 217 of the liquid effluent to a stripping step to recover an off-gas fraction 218 and a stripped liquid effluent 219. Separate the LPG fraction 226 from the gaseous effluent 218 and optionally send it to a steam cracking step f). Send the stripped liquid effluent 219 to a fractionation step e) to recover at least two liquid effluents, including a paraffin-rich naphtha fraction 221 and a heavy fraction 220 with a boiling point above 150 °C, which are recycled to the hydrotreating step a) and / or the hydrocracking step b) for further conversion. Send the naphtha fraction 221 to a steam cracking step f) to produce an effluent 222 rich in ethylene, propylene and bio-based light olefins. Example

[0140] Example 1: Process for treating a feedstock from renewable sources according to the invention The characteristics of the rapeseed oil feedstock used are shown in the following table: Table 1 <![CDATA[Density at 15 °C (kg / m 3 )]]> 923.5 Oxygen (wt%) 11 Hydrogen (wt%) 11.4 Sulfur (wt ppm) 3 Nitrogen (wt ppm) 13 Phosphorus (wt ppm) <1 Magnesium (wt ppm) <1 Calcium (wt ppm) <1 Sodium (wt ppm) <1

[0141] The operating conditions in the hydrotreating section are shown in the following table: Table 2

[0142] The operating conditions in the hydrocracking (HCK) step are shown in the following table: Table 3 Pressure 6.0 MPa HSV <![CDATA[4 h -1 > Catalyst NiMo USY WABT 300℃ Hydrogen / hydrocarbon ratio <![CDATA[1000 Nm 3 / Sm 3 > Single-pass conversion 50 wt% Overall conversion (HCK reactor inlet - purge) / (HCK reactor inlet) 99.9 wt% Recycle heavy fraction flow rate / fresh feedstock flow rate (by weight) 1.1

[0143] The overall results of the method are shown in the following table: Table 4

[0144] The properties of naphtha with a C5-175 °C fractionation point are as follows: - Paraffinic feedstock: paraffin content greater than 99 wt% - Density 677 kg / m 3 - Sulfur < 1 wt ppm - Nitrogen < 1 wt ppm - Oxygen content < 0.1 wt% These properties make it a feedstock selected for the production of ethylene and propylene because it is very rich in paraffins.

[0145] The resulting biobased naphtha feedstock is sent to the steam cracker at a flow rate of 76 t / h. This paraffin-rich feedstock produces a high yield of biobased ethylene and propylene, with at least 65% of the feedstock entering the steam cracker.

[0146] The LPG fraction and / or the off-gas fraction can also be sent to the steam cracker.

[0147] Thus, different from the methods according to the prior art, the method according to the present invention enables the production of naphtha and LPG fractions almost completely. In addition, the method is carried out in a minimized number of equipment items because the hydrotreating and hydrocracking steps are combined without a separation step.

Claims

1. A method for treating a feedstock comprising triglycerides and / or fatty acids and / or esters from renewable sources, said method comprising the following steps: a) A step of hydrotreating the feedstock in the presence of hydrogen and at least one fixed-bed hydrotreating catalyst, which is carried out at a temperature between 280 °C and 410 °C, and at a relative pressure between 2.0 and 13.0 MPa, and at a space velocity between 0.3 and 5 h -1 -1, and a hydrotreated effluent is obtained; b) A step of hydrocracking the hydrotreated effluent obtained in step a) in the presence of hydrogen and at least one fixed-bed hydrocracking catalyst at a temperature between 280 °C and 410 °C, which is carried out at a pressure between 2.0 MPa and 13.0 MPa and at a space velocity between 0.5 and 10 h -1 -1, and obtaining a hydrocracked effluent; c) Separating the hydrocracked effluent obtained in step b) and obtaining at least one gaseous effluent containing hydrogen and a hydrocarbon-based liquid effluent; d) Stripping the hydrocarbon-based liquid effluent obtained in step c) and obtaining at least one off-gas fraction and a stripped liquid effluent; e) Fractionating the stripped liquid effluent obtained in step d) and obtaining at least one paraffin-rich naphtha fraction; f) Steam cracking at least a portion, preferably all, of the naphtha fraction obtained in step e) and obtaining at least one bio-based gaseous effluent containing ethylene and propylene.

2. The method according to claim 1, wherein the hydrotreating step a) is carried out at a hydrogen-to-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 .

3. The method according to any one of the preceding claims, wherein the at least one hydrotreating catalyst comprises a support and an active phase, the active phase comprising at least one Group 6 metal and optionally one or more Group 9 or 10 metals, and the active phase preferably contains only molybdenum (Mo), or nickel and molybdenum (NiMo), or cobalt and molybdenum (CoMo), or cobalt, nickel and molybdenum (CoNiMo).

4. The method according to any one of the preceding claims, wherein after the hydrotreating step a), a step of separating the hydrotreating effluent at a high temperature between 280 °C and 410 °C and a high pressure between 2.0 and 13.0 MPa and obtaining at least one gaseous effluent and a liquid effluent is carried out.

5. The method according to claim 4, wherein a portion of the liquid effluent obtained in the high temperature separation step is recycled to the hydrotreating step a).

6. The method according to any one of the preceding claims, wherein the hydrocracking step b) is carried out at a hydrogen-to-hydrocarbon ratio between 100 and 5000 Nm 3 / Sm 3 .

7. The method according to any one of the preceding claims, wherein the hydrocracking step b) is carried out at a minimum hydrogen partial pressure of 2.5 MPa.

8. The method according to any one of the preceding claims, wherein the at least one hydrocracking catalyst comprises a hydrogenation function and an acid function provided by a support having a large surface area with surface acidity, such as halogenated alumina, a combination of boron and aluminum oxides, amorphous silica-alumina, and zeolites Y, β, and ZSM.

9. The method according to any one of the preceding claims, wherein in step b), the single-pass conversion to hydrocarbon-based compounds is between 20 wt% and 100 wt%.

10. The method according to any one of the preceding claims, wherein after the separation step c), the gaseous effluent containing hydrogen obtained in step c) is purified and / or washed to remove contaminants, especially H2S, CO, and CO2, and then the washed gaseous effluent is recycled to at least the hydrotreating step a) and / or the hydrocracking step b).

11. The method according to any one of the preceding claims, wherein a portion of the liquid effluent obtained in step c) is recycled to step a) and / or step b), preferably recycled to step a).

12. The method according to any one of the preceding claims, wherein the off-gas fraction obtained in step d) is sent to a separation step to recover a depropanized gaseous off-gas fraction with low propane and butane content and an LPG fraction.

13. The method according to claim 12, wherein the LPG fraction is sent, either alone or as a mixture with the naphtha fraction obtained in step e), to the steam cracking step f) and fed into one or more furnaces of the steam cracking step f).

14. The method according to any one of the preceding claims, wherein in step e) of fractionating the stripped liquid effluent obtained in step d), a heavy fraction containing hydrocarbon compounds with a boiling point higher than 150 °C, preferably higher than 175 °C, is also obtained.

15. The method according to claim 14, wherein all or part of the heavy fraction obtained in step e) is recycled to the hydrotreating step a) and / or the hydrocracking step b), preferably at a recycle feedstock / fresh feedstock ratio between 0 and 4.

16. The method according to any one of the preceding claims, wherein the feedstock is selected from vegetable oils such as rapeseed oil, jatropha oil, soybean oil, palm oil, sunflower oil, olive oil, coconut oil, camelina oil, fish oil or heterotrophic or autotrophic algal oils, animal fats, residues from the paper industry or mixtures of these various feedstocks.

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