Method for the treatment of plastic and / or tire pyrolysis oils, including removal of halides by washing prior to a hydrotreatment step

Abstract

The present invention relates to a method for treating a plastic and / or tire pyrolysis oil, comprising: a) hydrogenating the feedstock in the presence of hydrogen and a catalyst to obtain a hydrogenated effluent, b) separating the hydrogenated effluent at a temperature higher than the precipitation temperature of the ammonium halides formed in step a) and at a high pressure to obtain a gaseous effluent and a liquid effluent, c) separating at a temperature lower than the precipitation temperature and at a high pressure and fed by the gaseous effluent and at least some of the liquid effluent from step b) and an aqueous solution, to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent, d) hydrotreating said hydrocarbon effluent in the presence of hydrogen and a catalyst to obtain a hydrotreated effluent.

Description

[0001] PROCESS FOR TREATING PYROLYSIS OILS FROM PLASTICS AND / OR TIRE INCLUDING THE REMOVAL OF HALIDES BY WASHING BEFORE A

[0002] HYDROTREATMENT STAGE

[0003] Technical field

[0004] The present invention relates to a method for treating a plastic and / or tire pyrolysis oil in order to obtain a hydrocarbon effluent which can be recovered in a gasoline, jet or diesel fuel storage unit or as a feedstock for a steam cracking unit. More particularly, the present invention relates to a method for treating a feedstock resulting from the pyrolysis of plastic or tire waste in order to at least partially eliminate impurities, and in particular halides, between two catalytic stages using hydrogen.

[0005] Prior art

[0006] Plastic waste is generally a mixture of several polymers, for example, mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, and polystyrene. In addition, depending on the uses, plastics may contain, in addition to polymers, other compounds, such as plasticizers, pigments, dyes, or even residues from polymerization catalysts. Plastic waste may also contain, to a minor extent, biomass from, for example, household waste.

[0007] As for tires, they are mainly made of rubber for their elastic property (mixture of elastomers of the crosslinked natural and synthetic rubber type, added with additives of the silica, resin, sulfur, zinc oxide, carbon black, etc. type) and textile and metallic fibers for their reinforcing property.

[0008] Plastics from collection and sorting channels or recycled tires can undergo a pyrolysis step to obtain, among other things, pyrolysis oils. These oils generally contain many impurities, in particular halogenated compounds, including chlorine-based compounds, but also diolefins, olefins, metals, including iron, silicon, or heteroelements such as sulfur, oxygen and nitrogen, and insolubles.

[0009] These plastic and / or tire pyrolysis oils are generally burned to generate electricity and / or used as fuel in industrial or district heating boilers. Another way of valorizing plastic and / or tire pyrolysis oils is to use these pyrolysis oils as feedstock for a steam cracking unit in order to (re)create olefins, the latter being monomers constituting certain polymers.

[0010] Pyrolysis oils from plastics and / or tires can also be recovered as gasoline, jet or diesel fuels.

[0011] However, plastic and / or tire pyrolysis oils often contain impurities at high levels that are incompatible with direct storage in a fuel storage unit or with steam cracking units or units located downstream of steam cracking units, including polymerization processes and selective hydrogenation processes. These impurities can generate operability problems, including corrosion problems (particularly due to the presence of chlorine), coking or catalytic deactivation, or even incompatibility problems in the uses of the target polymers. The presence of diolefins can also lead to problems of instability of the pyrolysis oil characterized by the formation of gums. Gums and insolubles possibly present in the pyrolysis oil can generate clogging problems in the processes.

[0012] One way to remove these impurities from plastic and / or tire pyrolysis oils is to carry out hydrotreatment (H DT) in the presence of catalysts.

[0013] The most problematic impurities contained in plastic and / or tire oils are often halides, and more specifically chlorine. Indeed, chlorine is generally the limiting contaminant for treating pyrolysis oils in existing refinery units. Chlorine, even at low levels (e.g. <5 ppm by weight), is responsible for corrosion (in the form of HCl) which can occur in existing units whose metallurgy is generally not designed to withstand even low chlorine levels. Another problem related to the presence of halides in pyrolysis oils, and particularly chlorine, is the formation of ammonium chloride salts which are formed by reaction between chloride ions, released by hydrodechlorination in the form of HCl, and ammonium ions, generated by the hydrogenation of nitrogen compounds (hydrodenitrogenation) in the form of NH3 during a hydrogenation and / or hydrotreatment step.It is known that these ammonium chloride salts precipitate at a relatively low temperature (e.g. below 280°C) which creates clogging problems particularly in transfer lines and / or in sections of a process downstream of hydrogenation / hydrotreatment. Methods for removing chlorine by hydrotreatment in pyrolysis oil are for example known from documents: W020020769, W020016400, WO20239729, WO2 1105326 or WO16142809.

[0014] Document WO16142809 describes in particular a process including a pyrolysis step, a hydrotreatment step, a step of separation of the gases (C1 to C4 containing H2S and HCl) and a C5+ liquid, a step of dechlorination of the C5+ liquid by adsorption or a second hydrotreatment step, possibly another step of separation of the gases containing HCl, then a steam cracking step.

[0015] It is also known to remove the HCI formed during hydrotreatment by washing with water after a hydrotreatment step. Such washes are described in WO17083018, WO20254634 or WO22101333. In none of these documents is a washing before a hydrotreatment step described, nor is the problem of deactivating the hydrotreatment catalyst of a second hydrotreatment step downstream of a first hydrotreatment step by a deposit of chlorinated compounds described.

[0016] Unpublished patent application FR 21 / 12.908 describes a process for treating a plastic pyrolysis oil, comprising: a) a step of hydrogenation of the feedstock in a mixture with at least a portion of a liquid effluent from separation step c) and hydrogen, b) a step of hydrotreatment of the effluent from step a) in the presence of hydrogen, c) a separation step, fed with the effluent from step b), said step being carried out at a temperature of between 200 and 450°C and at a pressure substantially identical to the pressure of step b) to obtain at least a first gaseous effluent, and a liquid effluent, a portion of which is recycled upstream of step a), d) a separation step, fed with the first gaseous effluent and another portion of the liquid effluent from step c) and an aqueous solution, said step being carried out at a temperature of between 20 and below at 200°C,and at a pressure substantially identical to or lower than the pressure of step c), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent.,

[0017] One of the objectives of application FR 21 / 12.908 is to eliminate, by the combination of hot separation step c) followed by cold separation / washing step d), chlorine in the form of ammonium chloride salts. The chloride ions, released by the hydrogenation of chlorinated compounds in HCl form during steps a) and b) (hydrodechlorination) and the ammonia generated by the hydrogenation of nitrogen compounds in the form of NH3 during step b) in particular (hydrodenitrogenation), are largely released into the gaseous effluent thanks to the hot separation of step c). Indeed, the high temperature of this separation step c) prevents the precipitation of ammonium chloride salts which are formed by reaction between chloride ions and ammonium ions. Separation at a lower temperature in step d) of the gaseous effluent and part of the liquid effluent causes these ammonium chloride salts to precipitate.The water washing in this step d) allows these salts to be dissolved in the aqueous effluent. This produces a hydrocarbon effluent free of chlorine.

[0018] This same principle of chlorine removal by hot stripping in order to keep the ammonia and halides in the gas phase until a quantity of water is available to collect the ammonium halides in solution is also described in WO22101333. In this document, this separation occurs, as in application FR 21 / 12.908, after two HDT stages with a view to sending the purified oil to a steam cracking stage, the objective being to avoid the precipitation of solid ammonium halides on the internal surfaces of the equipment and corrosion.

[0019] The present invention provides an improvement to the process according to FR 21 / 12.908 by proposing the elimination of chlorine not after the hydrotreatment step, but between the hydrogenation step and the hydrotreatment step.

[0020] The applicant has noticed that the chlorine contained in the feedstock is almost completely converted in the hydrogenation step. It has also observed that by sending the effluent from the hydrogenation step directly into the hydrotreatment step, the chlorine (in the form of HCl) contained in the effluent from the hydrogenation step is deposited on the hydrotreatment catalyst, thus leading to a decrease in activity and a reduction in the duration of the catalytic cycle. In order to avoid clogging of the hydrotreatment catalyst and a decrease in activity, the present invention proposes to remove the chlorine before the hydrotreatment step.

[0021] Objectives and Summary of the Invention

[0022] More specifically, the invention relates to a method for treating a feedstock comprising a plastic and / or tire pyrolysis oil comprising halogenated compounds, said method comprising: a) a hydrogenation step carried out in a hydrogenation reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrogenation catalyst, said hydrogenation reaction section being supplied at least with said feedstock optionally mixed with at least a portion of a liquid effluent from a separation step b) and a first gaseous stream comprising hydrogen, said hydrogenation reaction section being carried out at an average temperature between 140 and 400°C, a hydrogen partial pressure between 1.0 and 10.0 MPa abs. and an hourly volumetric flow rate between 0.1 and 10.0 h -1, to obtain a hydrogenated effluent, b) a separation step, fed with the hydrogenated effluent from step a), said step being carried out at a temperature higher than the precipitation temperature of the ammonium halides and at a pressure substantially identical to the pressure of step a) to obtain at least a first gaseous effluent and a liquid effluent, part of which is optionally recycled upstream of step a), c) a separation step, fed with the first gaseous effluent and optionally at least part of the liquid effluent from step b), and an aqueous solution, said step being carried out at a temperature lower than the precipitation temperature of the ammonium halides and at a pressure substantially identical or lower than the pressure of step b), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent,d) a hydrotreatment step carried out in a hydrotreatment reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrotreatment catalyst, said hydrotreatment reaction section being fed at least by said hydrocarbon effluent from step c), optionally by at least a portion of the liquid effluent from step b), and a second gas stream comprising hydrogen, said hydrotreatment reaction section being carried out at an average temperature between 250 and 430°C, a partial pressure of hydrogen between 1.0 and 10.0 MPa abs. and an hourly volumetric flow rate between 0.1 and 10.0 h, -1, to obtain a hydrotreated effluent, e) optionally a step of fractionating all or part of the hydrotreated effluent from step d), to obtain at least a third gaseous effluent, a naphtha cut and at least one middle distillate cut, f) optionally a hydrocracking step carried out in a hydrocracking reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a part of said hydrotreated effluent from step d) and / or with at least a part of the middle distillate cut from step e) and a third gaseous stream comprising hydrogen, said hydrocracking reaction section being carried out at an average temperature between 250 and 450°C, a partial pressure of hydrogen between 1.5 and 20.0 MPa abs.and an hourly volumetric velocity between 0.1 and 10.0 h. -1 to obtain a first hydrocracked effluent.

[0023] The major advantage of the present invention is to carry out the elimination of halogenated compounds before the hydrotreatment step, thus making it possible to protect the hydrotreatment catalyst while avoiding the precipitation of solid ammonium halides on the internal surfaces of the equipment and corrosion. The elimination of halogenated compounds before the hydrotreatment step thus makes it possible to avoid a loss of catalyst activity in the hydrotreatment step and limits a reduction in the duration of the catalytic cycle.

[0024] The halogenated compounds contained in the feed are almost completely converted in hydrogenation step a) into hydrogen halides (HCl for example), as well as a portion of the nitrogen compounds into gaseous ammonia NH3. Hot separation (step b), i.e. at a temperature higher than the precipitation temperature of the ammonium halides, allows the ammonia and halides to be kept essentially in the gaseous phase and a liquid effluent to be obtained that is essentially free of these contaminants. Cold separation (step c), i.e. at a temperature lower than the precipitation temperature of the ammonium halides and in the presence of an aqueous solution, causes these ammonium halide salts to precipitate while dissolving them in water.This produces a hydrocarbon effluent freed from halogenated compounds which is introduced into hydrotreatment step d) in order to eliminate the remaining impurities without observing the deposition of halogenated compounds on the catalyst.

[0025] Removing halogenated compounds before the hydrotreatment step allows hydrotreatment step c) to be carried out at a lower average temperature than without prior removal of halogenated compounds, which saves energy.

[0026] In addition, an increase in the cycle time of the hydrotreatment section is observed. Cycle time is defined as the duration of catalyst use without the need for catalyst replacement.

[0027] Cold separation step c) can be carried out on the gaseous effluent (alone) or on the gaseous effluent and liquid effluent mixture. Carrying out cold separation step c) on the gaseous effluent and liquid effluent mixture has the advantage of extracting not only the contaminants from the gaseous effluent, but also the hydrogen halides (HCl) dissolved in the liquid effluent. Another advantage of the process according to the invention is to purify an oil resulting from the pyrolysis of plastic waste from at least some of its impurities, which makes it possible to hydrogenate it and thus to be able to recover it, in particular by incorporating it directly into the fuel storage unit or by making it compatible with treatment in a steam cracking unit in order to be able to obtain, in particular, light olefins with increased yields which can be used as monomers in the manufacture of polymers.

[0028] Another advantage of the invention is to prevent risks of blockage and / or corrosion of the treatment unit in which the process of the invention is implemented, the risks being exacerbated by the presence, often in significant quantities, of diolefins, metals and halogenated compounds in the pyrolysis oil.

[0029] The process of the invention thus makes it possible to obtain a hydrotreated effluent from a pyrolysis oil freed at least in part from the impurities of the starting pyrolysis oil, thus limiting the operability problems, such as corrosion, coking or catalytic deactivation problems, which these impurities can cause, in particular in the steam cracking units and / or in the units located downstream of the steam cracking units, in particular the polymerization and hydrogenation units. The elimination of at least part of the impurities from the oils resulting from the pyrolysis of plastic waste also makes it possible to increase the range of applications of the target polymers, the incompatibilities of use being reduced.

[0030] According to a variant, step b) is carried out at a temperature between 200 and 450°C and step c) is carried out at a temperature greater than or equal to 20°C and less than 200°C.

[0031] According to a variant, step c) is supplied with the first gaseous effluent and at least part of the liquid effluent from step b) and an aqueous solution.

[0032] According to one variant, at least part of the liquid effluent obtained in step b) is recycled upstream of step a).

[0033] According to one variant, the method comprises the fractionation step e).

[0034] According to one variant, the process comprises the hydrocracking step f).

[0035] According to a variant, in step a) the hydrogen coverage is between 250 and 800 Nm 3 of hydrogen per m 3 load (Nm 3 / m 3 ).

[0036] According to one variant, the method comprises a step aO) of pretreatment of the pyrolysis oil fraction of plastics and / or tires, said pretreatment step being carried out upstream of step a) and comprises an adsorption step and / or a filtration step and / or a centrifugation step and / or a decantation step and / or an electrostatic separation step and / or a washing step using an aqueous solution and / or a gas stripping step.

[0037] According to a variant, the hydrotreated effluent from hydrotreatment step d), or at least one of the two liquid hydrocarbon cuts from step e), is sent in whole or in part to a steam cracking step g) carried out in at least one pyrolysis furnace at a temperature between 700 and 900°C and at a pressure between 0.05 and 0.3 MPa relative.

[0038] According to a variant, the reaction section of step a) uses at least two reactors operating in switchable mode.

[0039] According to one variant, a stream containing an amine and / or a sulfur compound is injected upstream of step a).

[0040] According to one variant, said hydrogenation catalyst comprises a support chosen from alumina, silica, silica-aluminas, magnesia, clays and their mixtures and a hydro-dehydrogenating function comprising either at least one element from group VIII and at least one element from group VIB, or at least one element from group VIII.

[0041] According to one variant, said hydrotreatment catalyst comprises a support chosen from the group consisting of alumina, silica, silica-aluminas, magnesia, clays and their mixtures, and a hydro-dehydrogenating function comprising at least one element from group VIII and / or at least one element from group VIB.

[0042] According to a variant, the method further comprises a second hydrocracking step f') carried out in a hydrocracking reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a first hydrocracking effluent from the first hydrocracking step f) and a gas stream comprising hydrogen, said hydrocracking reaction section being carried out at a temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 MPa abs. and an hourly volumetric flow rate between 0.1 and 10.0 h' 1 , to obtain a second hydrocracked effluent.

[0043] According to one variant, said hydrocracking catalyst comprises a support chosen from halogenated aluminas, combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites and a hydro-dehydrogenating function comprising at least one metal from group VI B chosen from chromium, molybdenum and tungsten, alone or as a mixture, and / or at least one metal from group VIII chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0044] The invention also relates to the product capable of being obtained, and preferably obtained by the process according to the invention.

[0045] According to this variant, the product comprises, in relation to the total weight of the product:

[0046] - a total content of metallic elements less than or equal to 10.0 ppm by weight,

[0047] - with an iron element content of less than or equal to 200 ppb by weight,

[0048] - a silicon element content less than or equal to 5.0 ppm by weight,

[0049] - a sulfur content less than or equal to 500 ppm by weight,

[0050] - a nitrogen content less than or equal to 100 ppm by weight,

[0051] - a chlorine element content less than or equal to 10 ppm by weight

[0052] - a mercury content less than or equal to 5 ppb by weight.

[0053] According to the present invention, the pressures are absolute pressures, also noted abs., and are given in absolute MPa (or MPa abs.), unless otherwise indicated.

[0054] In this description, the term "include" is synonymous with (means the same as) "include" and "contain", and is inclusive or open and does not exclude other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist".

[0055] In this description, the expression "between ... and ..." means that the limiting values ​​of the interval are included in the range of values ​​described, unless otherwise specified.

[0056] For the purposes of the present invention, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, for the purposes of the present invention, a range of preferred pressure values ​​may be combined with a range of more preferred temperature values.

[0057] In the following, particular and / or preferred embodiments of the invention may be described. They may be implemented separately or combined with each other, without limitation of combination when technically feasible. In the following text, the term "pyrolysis oil" means an oil resulting from the pyrolysis of plastics and / or tires, unless otherwise indicated.

[0058] In the following, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, 81 ème edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IIIPAC classification.

[0059] The metal content is measured by X-ray fluorescence.

[0060] Detailed description

[0061] The charge

[0062] According to the invention, a “plastic pyrolysis oil” or “tire pyrolysis oil” is an oil, advantageously in liquid form at room temperature, resulting from the pyrolysis of plastics, preferably plastic waste originating in particular from collection and sorting channels, or resulting from the pyrolysis of used tires.

[0063] It comprises in particular a mixture of hydrocarbon compounds, in particular paraffins, mono- and / or di-olefins, naphthenes and aromatics. At least 80% by weight of these hydrocarbon compounds preferably have a boiling point below 700°C, and preferably below 550°C. In particular, depending on the origin of the pyrolysis oil, it may comprise up to 70% by weight of paraffins, up to 90% by weight of naphthenes, up to 90% by weight of olefins and up to 90% by weight of aromatics, it being understood that the sum of the paraffins, naphthenes, olefins and aromatics is 100% by weight of the hydrocarbon compounds.

[0064] The oil may contain diolefins. The diolefin content is commonly determined indirectly as the maleic anhydride value (MAV). The method is based on the Diels-Alder addition reaction between conjugated diolefins and maleic anhydride. The method for determining MAV is described in C. Lôpez-Garcia et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil & Gas Science and Technology - Rev. IFP, Vol. 62 (2007), No. 1, pp. 57-68. MAV is expressed as mg of maleic anhydride reacted with 1 g of sample (mg / g). MAV ranges between 5 and 100 mg / g in pyrolysis oils.

[0065] The density of pyrolysis oil, measured at 15°C according to ASTM D4052, is generally between 0.75 and 0.99 g / cm 3 , preferably between 0.75 and 0.95 g / cm 3. Pyrolysis oil may include, and most often does include, additional impurities such as metals, in particular iron, silicon, halogenated compounds, in particular chlorinated compounds. These impurities may be present in the pyrolysis oil at high levels, for example up to 600 ppm by weight or 700 ppm by weight or even 1000 ppm by weight and even 5000 ppm by weight of halogenated elements (in particular chlorine but also bromine, fluorine, iodine) provided by halogenated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or between 1 and 600 ppm by weight of halogenated elements. Pyrolysis oil can contain up to 600 ppm by weight or 700 ppm by weight or even 1000 ppm by weight or even 5000 ppm by weight of chlorine element provided by chlorinated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or even between 1 and 600 ppm by weight of chlorine elements.

[0066] The oil may contain up to 200 ppm by weight, or even 1500 ppm by weight of metallic or semi-metallic elements, and generally between 1 and 200 ppm by weight or between 1 and 1500 ppm by weight of metallic or semi-metallic elements. Alkali metals, alkaline earth metals, transition metals, poor metals and metalloids may be considered as contaminants of a metallic nature, called metals or metallic or semi-metallic elements. In particular, metals or metallic or semi-metallic elements include silicon, iron or both of these elements. Pyrolysis oil may contain, in particular, up to 200 ppm by weight or even 1000 ppm by weight of silicon, and generally between 1 and 200 ppm by weight or between 1 and 1000 ppm by weight or even between 1 and 500 ppm by weight of silicon. Pyrolysis oil can contain up to 50 ppm by weight or 100 ppm by weight of iron, and generally between 1 and 50 ppm by weight or between 1 and 100 ppm by weight of iron.Pyrolysis oil may also include phosphorus, sodium, calcium, potassium, and magnesium.

[0067] The pyrolysis oil may also comprise other impurities such as heteroelements provided in particular by sulfur compounds, oxygenated compounds and / or nitrogen compounds, at contents generally less than 40,000 ppm by weight of heteroelements and preferably less than 15,500 ppm by weight of heteroelements, and generally between 1 and 40,000 ppm by weight or between 1 and 15,500 ppm by weight of heteroelements. The sulfur compounds are generally present in a content of less than 15,000 ppm by weight and preferably less than 10,000 ppm by weight, and generally between 1 and 15,000 ppm by weight or between 1 and 10,000 ppm by weight of sulfur compounds.

[0068] The oxygenated compounds are generally present in a content of less than 15,000 ppm by weight and preferably less than 10,000 ppm by weight, and generally between 1 and 15,000 ppm by weight or between 1 and 10,000 ppm by weight of oxygenated compounds. The nitrogenous compounds are generally present in a content of less than 10,000 ppm by weight and preferably less than 5,000 ppm by weight, and generally between 1 and 10,000 ppm by weight or between 1 and 5,000 ppm by weight of nitrogenous compounds.

[0069] Pyrolysis oil may also include other impurities such as heavy metals such as mercury, arsenic, zinc and lead, for example up to 100 ppb by weight or 200 ppb by weight of mercury or arsenic, and generally between 1 and 200 ppb by weight or between 1 and 100 ppb by weight of heavy metals.

[0070] The feedstock of the process according to the invention comprises at least one pyrolysis oil. Said feedstock may consist solely of pyrolysis oil(s). Preferably, said feedstock comprises at least 50% by weight, preferably between 70 and 100% by weight, of pyrolysis oil relative to the total weight of the feedstock, i.e. preferably between 50 and 100% by weight, preferably between 70% and 100% by weight of pyrolysis oil.

[0071] The feedstock of the process according to the invention may comprise, in addition to the oil or oils, a conventional petroleum feedstock or a feedstock resulting from the conversion of biomass which is then co-treated with the pyrolysis oil of the feedstock.

[0072] The conventional petroleum feedstock can advantageously be a cut or a mixture of cuts of the naphtha, diesel or vacuum diesel type.

[0073] The feedstock resulting from biomass conversion may advantageously be selected from vegetable oils, algae or algal oils, fish oils, used edible oils, and fats of vegetable or animal origin; or mixtures of such feedstocks. The oils / fats of vegetable and / or animal origin contain triglycerides and / or free fatty acids and / or esters. Said vegetable oils may advantageously be crude or refined, totally or partially, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, jatropha (purjore), copra, castor oil, cottonseed, peanut, linseed and crambe oils and all oils derived for example from sunflower or rapeseed by genetic modification or hybridization, this list not being exhaustive. Algal or fish oils are also relevant.Animal fats are advantageously chosen from lard and fats composed of residues from the food industry or from the catering industry. Frying oils, various animal oils such as fish oils, tallow, and lard can also be used.

[0074] The feedstock from biomass conversion may also be selected from feedstocks from thermal or catalytic biomass conversion processes, such as oils that are produced from biomass, particularly lignocellulosic biomass, with various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, which includes plants, animals and their by-products. The term "lignocellulosic biomass" refers to biomass derived from plants or their by-products. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and an aromatic polymer (lignin).

[0075] The feedstock from biomass conversion can also advantageously be chosen from feedstocks from the paper industry.

[0076] Pyrolysis oil can be produced by thermal or catalytic pyrolysis treatment or can be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0077] (aO) Pre-processing step (optional)

[0078] Said feedstock comprising a pyrolysis oil may advantageously be pretreated in an optional pretreatment step aO), prior to step a) of hydrogenation, to obtain a pretreated feedstock which feeds step a).

[0079] This optional pretreatment step aO) makes it possible to reduce the quantity of contaminants and solid particles, in particular the quantity of iron and / or silicon and / or chlorine, possibly present in the feed comprising a pyrolysis oil. Thus, an optional step aO) of pretreatment of the feed comprising a pyrolysis oil is advantageously carried out in particular when said feed comprises more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of metallic elements and / or solid particles, and in particular when said feed comprises more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, or even more than 20 ppm by weight of silicon.Likewise, an optional step aO) of pretreatment of the feed comprising a pyrolysis oil is advantageously carried out in particular when said feed comprises more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of chlorine.

[0080] Said optional pretreatment step aO) may be implemented by any method known to those skilled in the art for reducing the quantity of contaminants. It may in particular comprise an adsorption step and / or a filtration step and / or a centrifugation step and / or a decantation step and / or an electrostatic separation step and / or a step of washing using an aqueous solution and / or a gas stripping step. The optional pretreatment step aO) is advantageously implemented at a temperature of between 20 and 400°C, preferably between 40 and 350°C, and at a pressure of between 0.15 and 10.0 MPa abs, preferably between 0.2 and 7.0 MPa abs.

[0081] According to a variant, said optional pretreatment step aO) is implemented in an adsorption section operated in the presence of at least one adsorbent. The adsorbent may be chosen from a zeolite, activated carbon, a clay, a silica or an alumina.

[0082] Advantageously, said adsorbent comprises less than 1% by weight of metallic elements, preferably is free of metallic elements. By metallic elements of the adsorbent are meant the elements of groups 6 to 10 of the periodic table of elements (new IIIPAC classification). The residence time of the load in the adsorption section is generally between 1 and 180 minutes.

[0083] Said adsorption section of the optional step aO) comprises at least one adsorption column, preferably comprises at least two adsorption columns, preferably between two and four adsorption columns, containing said adsorbent. When the adsorption section comprises two adsorption columns, an operating mode may be a so-called "swing" operation, according to the established English term, in which one of the columns is online, i.e. in operation, while the other column is in reserve. When the absorbent of the online column is used up, this column is isolated while the column in reserve is put online, i.e. in operation. The used absorbent can then be regenerated in situ and / or replaced with fresh absorbent so that the column containing it can be put back online once the other column has been isolated.

[0084] Another operating mode is to have at least two columns operating in series. When the absorbent in the column placed at the head is worn out, this first column is isolated and the worn absorbent is either regenerated in situ or replaced with fresh absorbent. The column is then put back online in the last position and so on. This operation is called permutable mode, or according to the English term "PRS" for Permutable Reactor System or "lead and lag" according to the English term "lead and lag". The association of at least two adsorption columns makes it possible to overcome the possible and possibly rapid poisoning and / or clogging of the adsorbent under the combined action of metallic contaminants, diolefins, gums from diolefins and insolubles possibly present in the pyrolysis oil to be treated.The presence of at least two adsorption columns facilitates the replacement and / or regeneration of the adsorbent, advantageously without stopping the pretreatment unit, or even the process, thus reducing the risk of clogging and therefore avoiding stopping the unit due to clogging, controlling costs and limiting adsorbent consumption.

[0085] According to another variant, said optional pretreatment step aO) is implemented in a washing section with an aqueous solution, for example water or an acidic or basic solution. This washing section may comprise equipment for bringing the feedstock into contact with the aqueous solution and separating the phases so as to obtain the pretreated feedstock on the one hand and the aqueous solution comprising impurities on the other hand. Among this equipment, there may be for example a stirred reactor, a decanter, a mixer-decanter and / or a co- or counter-current washing column.

[0086] According to another variant, said optional pretreatment step aO) is implemented by filtration. The filtration step makes it possible to remove inorganic solids, sediments and / or fines contained in the oil, in particular metals, metal oxides and metal chlorides. A filter is generally used whose pore size (for example the diameter or equivalent diameter) is less than 25 μm, preferably less than or equal to 10 μm, even more preferably less than or equal to 5 μm. According to another variant, a filter may be used whose pore size is less than 25 μm but greater than 5 μm. A series of filters with different pore sizes may also be used, in particular a series of filters having decreasing pore sizes in the direction of oil circulation. These filter media are well known for industrial uses.Cartridge filters and self-cleaning filters are suitable, for example. The solids content can be measured, for example, using the Heptane Insolubles test, ASTM Method D-3279. The heptane insolubles content should be reduced to less than 0.5% by weight, preferably less than 0.1%.

[0087] According to a particular embodiment, the pretreatment step aO) by filtration comprises at least one filter whose pore size is less than 10 microns, and preferably greater than 5 pm, optionally followed by a filtration system whose pore size is less than 2 pm and preferably less than 1 pm.

[0088] According to another particular embodiment, the pretreatment step aO) by filtration comprises at least one filter whose pore size is less than 10 pm, and preferably greater than 5 pm, followed by an electrostatic precipitation system.

[0089] According to another particular embodiment, the pretreatment step aO) by filtration comprises at least one filter whose pore size is less than 10 μm, and preferably greater than 5 μm, followed by a system of filter(s) using filtration aids such as sand or diatomaceous earth. According to another variant, said optional pretreatment step aO) is implemented by centrifugation. According to another variant, the pretreatment step aO) comprises centrifugation and filtration.

[0090] According to another variant, said optional pretreatment step aO) is implemented by decantation. According to another variant, the pretreatment step aO) comprises decantation and filtration.

[0091] According to another variant, said optional pretreatment step aO) is carried out by gas stripping, thereby reducing the oxygen content in the oil. The gas stripping may remove oxygen (O2) that may be dissolved in the feedstock thereby reducing the likelihood of free radical formation leading to polymerization in downstream steps. The method generally involves contacting the oil with a stripping gas (e.g. H2, N2 or a mixture thereof), thereby transferring at least some of the dissolved oxygen from the oil to the stripping gas, followed by separating the stripping gas from the oil. The volume of stripping gas relative to the volume of oil (both volumes measured under gas stripping conditions) is generally greater than 1, and preferably at least 3. In particular embodiments, the stripping gas may contain at least 60% (molar percentage) H2.Any dissolved H2 remaining in the feedstock after the gas stripping step is not a problem, given the downstream hydrodemetallization / hydrotreatment. Preferably, the gas stripping step is completed before any (pre)heating of the feedstock, to minimize potential fouling.

[0092] Said optional pretreatment step aO) generally comprises one or more, preferably several treatments described above. It may in particular comprise a sequence of a washing step using an aqueous solution and / or an adsorption step, followed by a gas stripping step, followed by a filtration step and / or a centrifugation step. All these steps are preferably carried out before any (pre)heating of the load.

[0093] Said optional pretreatment step aO) may also optionally be supplied with at least a portion of the liquid effluent from step b) of the process and / or a portion of at least one of the cuts from step e), in a mixture or separately from the feedstock comprising a pyrolysis oil. The recycling of at least a portion of the liquid effluent from step b) makes it possible in particular to increase sedimentation and therefore, after possible filtration, to improve the pretreatment of the feedstock.

[0094] Said optional pretreatment step aO) thus makes it possible to obtain a pretreated feedstock which then feeds the hydrogenation step a). (a) Hydrogenation step

[0095] According to the invention, the process comprises a hydrogenation step a) implemented in a hydrogenation reaction section, implementing at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrogenation catalyst, said hydrogenation reaction section being supplied at least with said feedstock, optionally pretreated, optionally mixed with at least a portion of liquid effluent from step b) and a first gaseous stream comprising hydrogen, said hydrogenation reaction section being implemented at an average temperature between 140 and 400°C, a partial pressure of hydrogen between 1.0 and 10.0 MPa abs. and an hourly volumetric velocity between 0.1 and 10.0 h' 1 , to obtain a hydrogenated effluent.

[0096] Step a) is carried out in particular under hydrogen pressure and temperature conditions enabling the hydrogenation of the diolefins and olefins to be carried out at the start of the hydrogenation reaction section while enabling, by means of a rising temperature profile, the hydrodemetallation and hydrodechlorination to be carried out, in particular at the end of the hydrogenation reaction section. A necessary quantity of hydrogen is injected so as to enable the hydrogenation of at least a portion of the diolefins and olefins present in the plastic pyrolysis oil, the hydrodemetallation of at least a portion of the metals, in particular the retention of silicon, and also the conversion of at least a portion of the chlorine (into HCl).The hydrogenation of diolefins and olefins thus makes it possible to avoid or at least limit the formation of "gums", i.e. the polymerization of diolefins and olefins and therefore the formation of oligomers and polymers, which can block the reaction section of hydrotreatment step d). In parallel with the hydrogenation, hydrodemetallation, and in particular the retention of silicon during step a), makes it possible to limit the catalytic deactivation of the reaction section of hydrotreatment step d). In addition, the conditions of step a) make it possible to convert at least part of the chlorine, and preferably all of the chlorine.

[0097] The person skilled in the art easily understands that, in hydrogenation step a), hydrogenation reactions are carried out as described above but also in parallel some of the other hydrotreatment reactions, and in particular hydrodesulfurization and hydrodenitrogenation, even if these reactions are rather favored in hydrotreatment step d), which is generally carried out at a higher temperature.

[0098] The temperature in step a), whether the average temperature (WABT), the temperature at the inlet of the reaction section or the rise in temperature in step a) between the inlet and outlet of the reaction section, can in particular be controlled by injecting a diluent into step a), preferably a recycle of a portion of the liquid effluent from step b) and / or at least a portion of one or more cuts from step e), in particular by the recycle rate and / or by the temperature of the recycled effluent.

[0099] The temperature difference between the inlet and the outlet of the reaction section of step a) is understood to mean injection of a gaseous (hydrogen) or liquid cooling flow, in particular preferably a portion of the liquid effluent from step b).

[0100] The temperature difference between the inlet and the outlet of the reaction section of step a) is exclusively due to the exothermicity of the chemical reactions carried out in the reaction section and therefore does not include the use of a heating means (furnace, heat exchanger, etc.).

[0101] Said reaction section carries out hydrogenation in the presence of at least one hydrogenation catalyst, advantageously at an average temperature (or WABT as defined below) between 140 and 400°C, preferably between 240 and 350°C, and particularly preferably between 260 and 330°C, a hydrogen partial pressure between 1.0 and 10.0 MPa abs, preferably between 1.5 and 8.0 MPa abs. and at an hourly volumetric flow rate (WH) between 0.1 and 10.0 h' 1 , preferably between 0.2 and 5.0 h' 1 , and very preferably between 0.3 and 3.0 h' 1 .

[0102] According to the invention, the "average temperature" of a reaction section corresponds to the Weight Average Bed Temperature (WABT) according to the established Anglo-Saxon term, well known to those skilled in the art. The average temperature is advantageously determined according to the catalytic systems, the equipment, and the configuration thereof, used. The average temperature (or WABT) is calculated as follows:

[0103] WABT = (Tætgg + T SfiJ flg) 2 with Tinput: the temperature of the flow entering the reaction section and Toutput: the temperature of the effluent leaving the reaction section. Unless otherwise indicated, the “average temperature” of a reaction section is given at start-of-cycle conditions.

[0104] The hourly volumetric flow rate (WH) is defined here as the ratio between the hourly volumetric flow rate of the feedstock comprising the pyrolysis oil, possibly pretreated, by the volume of catalyst(s). The hydrogen coverage is defined as the ratio of the volumetric flow rate of hydrogen taken under normal temperature and pressure conditions compared to the volumetric flow rate of the “fresh” feedstock, i.e. the feedstock to be treated, possibly pretreated, without taking into account a recycled fraction, and in particular without taking into account the liquid effluent from step b) recycled, at 15°C (in normal m 3 , noted Nm 3 , of H2 by m 3 dump).

[0105] The quantity of the gas flow comprising hydrogen (H2), feeding said reaction section of step a), is advantageously such that the hydrogen coverage is between 100 and 1500 Nm 3 of hydrogen per m 3 load (Nm 3 / m 3), preferably between 200 and 1000 Nm 3 of hydrogen per m 3 load (Nm 3 / m 3 ), preferably between 250 and 800 Nm 3 of hydrogen per m 3 load (Nm 3 / m 3 ).

[0106] Advantageously, the reaction section of said step a) comprises between 1 and 5 reactors, preferably between 2 and 5 reactors, and particularly preferably it comprises two reactors. The advantage of a hydrogenation reaction section comprising several reactors lies in an optimized treatment of the feedstock, while making it possible to reduce the risks of clogging of the catalytic bed(s) and therefore to avoid stopping the unit due to clogging.

[0107] According to a preferred variant, these reactors operate in permutable mode, called "PRS" for Permutable Reactor System or "lead and lag". The association of at least two reactors in PRS mode makes it possible to isolate a reactor, unload the spent catalyst, reload the reactor with fresh catalyst and put said reactor back into service without stopping the process. The PRS technology is described, in particular, in patent FR2681871.

[0108] According to a particularly preferred variant, the hydrogenation reaction section of step a) comprises two reactors operating in switchable mode.

[0109] Advantageously, reactor internals, for example of the filter tray type, can be used to prevent clogging of the reactor(s). An example of a filter tray is described in patent FR3051375.

[0110] Advantageously, said hydrogenation catalyst comprises a support, preferably mineral, and a hydro-dehydrogenating function.

[0111] According to one variant, the hydro-dehydrogenating function comprises in particular at least one element from group VIII, preferably chosen from nickel and cobalt, and at least one element from group VI B, preferably chosen from molybdenum and tungsten. According to this variant, the total content expressed as oxides of the metal elements from groups VI B and VIII is preferably between 1% and 40% by weight, preferably from 5% to 30% by weight relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MoOa and WO3 respectively.

[0112] The weight ratio expressed in metal oxide between the metal (or metals) of group VI B relative to the metal (or metals) of group VIII is preferably between 1 and 20, and preferably between 2 and 10.

[0113] According to this variant, the reaction section of said step a) comprises for example a hydrogenation catalyst comprising between 0.5% and 12% by weight of nickel, preferably between 0.9% and 10% by weight of nickel (expressed as nickel oxide NiO relative to the weight of said catalyst), and between 1% and 30% by weight of molybdenum, preferably between 3% and 20% by weight of molybdenum (expressed as molybdenum oxide MoOa relative to the weight of said catalyst) on a preferably mineral support, preferably on an alumina support.

[0114] According to another variant, the hydro-dehydrogenating function comprises, and is preferably made up of, at least one element from group VIII, preferably nickel. According to this variant, the content of nickel oxides is preferably between 1 and 50% by weight, preferably between 10% and 30% by weight relative to the weight of said catalyst. This type of catalyst is preferably used in its reduced form, on a preferably mineral support, preferably on an alumina support.

[0115] The support of said hydrogenation catalyst is preferably chosen from alumina, silica, silica-aluminas, magnesia, clays and mixtures thereof. Said support may contain doping compounds, in particular oxides chosen from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphoric anhydride and a mixture of these oxides. Preferably, said hydrogenation catalyst comprises an alumina support, optionally doped with phosphorus and optionally boron. When phosphoric anhydride P2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina. When boron trioxide B2O3 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% relative to the total weight of the alumina.The alumina used can be, for example, a y (gamma) or q (eta) alumina.

[0116] Said hydrogenation catalyst is for example in the form of extrudates. Very preferably, step a) may use, in addition to the hydrogenation catalyst(s) described above, also at least one hydrogenation catalyst used in step a) comprising less than 1% by weight of nickel and at least 0.1% by weight of nickel, preferably 0.5% by weight of nickel, expressed as nickel oxide NiO relative to the weight of said catalyst, and less than 5% by weight of molybdenum and at least 0.1% by weight of molybdenum, preferably 0.5% by weight of molybdenum, expressed as molybdenum oxide MoOa relative to the weight of said catalyst, on an alumina support. This catalyst, which is lightly loaded with metals, may preferably be placed upstream or downstream of the hydrogenation catalyst(s) described above, preferably upstream.

[0117] Preferably, step a) may use, upstream of the hydrogenation catalyst(s), at least one guard bed containing adsorbents of the alumina, silica-alumina, zeolite and / or activated carbon type, possibly containing metals from group VI B and / or VIII. It is also possible to use a series of guard beds with particles of different diameters, in particular a series of guard beds having decreasing diameters in the direction of circulation of the feedstock (also called "grading" according to English terminology).

[0118] According to a variant, the feedstock, before being preferably mixed with at least a portion of the effluent from step b), may be preheated by direct heating to a temperature of up to 200°C, preferably up to 180°C, and particularly preferably up to 150°C. Above this temperature, contact with a wall during direct heating may induce the formation of gums and / or coke, which may cause fouling and an increase in the pressure drop of the feedstock heating system and of the catalyst bed(s). Heating the feedstock to a temperature above 150°C, preferably above 180°C, and particularly preferably above 200°C is preferably carried out by indirect heating with a hot diluent, preferably with at least a portion of the effluent from step b).Thus, the temperature rise above 150°C, preferably above 180°C and particularly preferably above 200°C of the feedstock is caused by mixing with a hotter liquid, and not by contact with a heated wall. This makes it possible to locally limit high temperatures. This type of heating by mixing with an inert hot liquid therefore makes it possible to limit undesirable reactions such as the polymerization of diolefins (formation of gum) and / or the formation of coke, and to adjust the inlet temperature of the stream in step a) so as to initiate the hydrogenation reaction of the unsaturations, preferably at the lowest possible temperature, while controlling the exothermicity of these reactions by a dilution effect of the reactive species. According to another variant, the feedstock is entirely heated by indirect heating by at least part of the effluent from step b).In this case, the feedstock is not preheated before being mixed with at least part of the effluent from step b).

[0119] The energy required for the reaction and more precisely, the adjustment of the minimum temperature required for the activation of the saturation reactions of the double bonds is therefore advantageously achieved by mixing, upstream of step a), said feedstock comprising a pyrolysis oil and a hydrogen-rich gas, with a diluent and preferably a portion of the liquid effluent from separation step b), having optionally undergone a temperature adjustment and preferably having been either preheated or cooled and particularly preferably having been preheated.

[0120] Another heating stream advantageously consists of a hydrogen-rich gaseous effluent originating from the hydrogen make-up and / or the gaseous effluent from separation step c). At least a portion of this hydrogen-rich gaseous effluent originating from the hydrogen make-up and / or the gaseous effluent from separation step c) is advantageously injected, optionally in a mixture with at least a portion of the liquid effluent from step b) or separately, upstream of step a).

[0121] Said hydrogenation step a) makes it possible to obtain a hydrogenated effluent, i.e. an effluent with a reduced content of olefins, in particular diolefins, and metals, in particular silicon, and halogens, in particular chlorine. Hydrogenation step a) generally makes it possible to convert at least 40%, and preferably at least 60% of the diolefins as well as at least 40%, and preferably at least 60% of the olefins contained in the initial feedstock. The heat released by the saturation of the double bonds makes it possible to raise the temperature of the reaction medium and to initiate the hydrotreatment reactions, in particular the elimination, at least in part, of other contaminants, such as for example silicon and chlorine or nitrogen. Preferably, at least 50%, and more preferably at least 75% of the chlorine and silicon of the initial feedstock are respectively eliminated during step a). Generally, the silicon content is less than 10 ppm by weight.The effluent obtained at the end of hydrogenation step a) is sent, preferably directly, to hot separation step b).

[0122] (b) Hot separation step

[0123] According to the invention, the treatment method comprises a separation step b), fed with the effluent from step a), said step being carried out at a temperature higher than the precipitation temperature of the ammonium halides and at a pressure substantially identical to the pressure of step a) to obtain at least a first gaseous effluent, and a liquid effluent, a portion of which is preferably recycled upstream of step a). The high temperature of this separation step b) prevents the precipitation of ammonium halide salts which are formed by reaction between the halide ions and the ammonium ions in order to recover a gaseous effluent containing the majority of the halides in the form of hydrogen halides (HCl) and gaseous ammonia, and a liquid effluent containing very little halides and ammonia.

[0124] The precipitation temperature of ammonium halides is understood to mean the temperature (under given conditions, such as concentration and pressure) at which gaseous ammonia and hydrogen halides precipitate, either by reacting to form solid crystals of ammonium halides or by dissolving in water. The precipitation temperature depends on the halide concentrations and the pressure according to thermodynamic principles. The precipitation temperature of ammonium halides is generally between 150 and 300°C, often between 180 and 295°C, and particularly between 200° and 290°C, under the conditions of use of the present process.

[0125] The temperature at which the separation of step b) is carried out must be higher than the precipitation temperature of the ammonium halides in order to recover a gaseous effluent containing the majority of the halides in the form of hydrogen halides (HCl) and gaseous ammonia, and a liquid effluent containing very little halides and ammonia. The temperature at which the separation of step b) is carried out is generally between 200 and 450°C, preferably between 220 and 330°C, and particularly preferably between 240 and 300°C.

[0126] The term "pressure substantially equal to the pressure of step a)" means the pressure of step a) with a pressure difference of between 0 and 1 MPa, preferably of between 0.005 and 0.3 Mpa, and particularly preferably of between 0.01 and 0.3 Mpa relative to the pressure of step a). Preferably, the pressure of step b) is the pressure of step a) less the pressure losses.

[0127] Separation step b) can advantageously be implemented by any method known to those skilled in the art such as, for example, the combination of one or more separator(s) (balloon(s)), and / or one or more stripping column(s), this or these separator(s) (balloon(s)) and / or columns optionally being able to be supplied with a stripping gas, for example a hydrogen-rich gas stream. Preferably, step b) is implemented with a single separator (balloon).

[0128] Separation step b) is a so-called high pressure or medium pressure high temperature separation step, also known to those skilled in the art as HHPS (for “Hot High Pressure Separator” in English terminology). Thus, this step b) preferably uses a so-called “hot high pressure” separator, the pressure being substantially equal to the operating pressure of step a).

[0129] The gas / liquid separation has an efficiency corresponding to the solubility and Henry's law. This means that an equilibrium quantity of halides in the form of hydrogen halides will remain in the liquid effluent obtained in step b). These halides will be released into the gaseous effluent during step c) of cold separation and then evacuated by dissolution in the aqueous effluent.

[0130] Advantageously, part of the liquid effluent from step b) is recycled upstream of step a).

[0131] Mixing the feedstock and part of the liquid effluent (hot recycle) upstream of step a) allows, on the one hand, to dilute the impurities in the feedstock and, on the other hand, to control the temperature in step a) in which highly exothermic reactions (in particular the hydrogenation reactions of olefins and diolefins) occur. Mixing the feedstock and part of the liquid effluent (hot recycle) upstream of step a) also allows indirect heating of the feedstock, by simply mixing the "cold" feedstock with the hot recycle.

[0132] The quantity of liquid effluent from step b) recycled is adjusted so that the weight ratio between the recycle stream from step b) and the feed comprising a pyrolysis oil, i.e. the feed to be treated feeding the overall process, is less than or equal to 10, preferably less than or equal to 7, and preferably greater than or equal to 0.001, preferably greater than or equal to 0.01, and more preferably greater than or equal to 0.1. Preferably, the quantity of liquid effluent from step b) recycled is adjusted so that the weight ratio between the recycle stream and the feed comprising a pyrolysis oil is between 0.01 and 10, preferably between 0.1 and 7, and more preferably between 0.2 and 5. This recycle rate makes it possible to control the rise in temperature in step a).Indeed, when the recycle rate is high, the dilution rate of the feedstock is high, and the temperature rise at the start of the reaction section of step a), in particular due to the hydrogenation reactions of the diolefins, is thus controllable by the dilution effect.

[0133] According to a preferred variant, at least a portion of the liquid effluent from step b) can advantageously be either cooled, or preheated, if necessary, or kept at the same temperature as at the outlet of separation step b), before being preferably recycled upstream of hydrogenation step a), depending on the temperature and the flow rate of feedstock and hydrogen, so that the temperature of the incoming stream, comprising said feedstock preferably in a mixture with at least a portion of said liquid effluent from step b) and a hydrogen-rich gas, is between 140 and 400°C, preferably between 220 and 350°C, and particularly preferably between 260 and 330°C.

[0134] The high pressure and high temperature separation makes it possible on the one hand to maximize energy recovery by hot recycling of part of the liquid effluent. Indeed, the energy to reach the necessary inlet temperature in step a) is at least partly provided by the heat of part of the liquid effluent from step b) and also makes it possible to reduce or even eliminate any preheating by direct heating of the feedstock beyond a temperature above 200°C to avoid the formation of gums. In addition, the fact of preferably recycling at least part of the liquid effluent at high pressure makes it possible to save energy for its pressurization in step a).

[0135] High pressure and high temperature separation also makes it possible to minimize the quantity of light fraction (naphtha cut) contained in the liquid effluent. At this temperature, almost all of the light fraction of the effluent (naphtha) goes as gaseous effluent to the cold separation / washing step c) while in the liquid phase we have mainly the heavy fraction of the feed (middle distillate cut). When recycling part of the liquid effluent to step a), ppH2 is favored in step a) because the light fraction (naphtha) could partially vaporize and lower the ppH2 if it were not at least partially eliminated during the high pressure and high temperature separation. The elimination of the light fraction comprising the naphtha can optionally be increased by a slight expansion upstream of at least one separator implemented in step b), even if this implementation is not preferred due to the energy loss linked to the expansion.Another option to increase the removal of the light fraction including naphtha may be to perform stripping, for example by injecting a hydrogen-rich gas into step b).

[0136] (c) Cold separation and washing step

[0137] According to the invention, the treatment method comprises a separation step c), supplied with the first gaseous effluent and optionally at least part of the liquid effluent from step b) and an aqueous solution, said step being carried out at a temperature lower than the precipitation temperature of the ammonium halides, and at a pressure substantially identical to or lower than the pressure of step b), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent.

[0138] The separation of step c) at a temperature lower than the precipitation temperature of the ammonium halides from the gaseous effluent mixture and possibly at least part of the liquid effluent from step b) causes the ammonium halide salts to precipitate, which are formed by reaction between the halide ions and the ammonium ions contained in particular in the gaseous effluent.

[0139] Cold separation step c) is fed with the gaseous effluent alone from step b) or with the gaseous effluent mixture and at least part of the liquid effluent from step b). Preferably, cold separation step c) is fed with the gaseous effluent mixture and at least part of the liquid effluent. According to a particularly preferred variant, cold separation step c) is fed with the gaseous effluent mixture and all of the liquid effluent. Carrying out cold separation step c) on the gaseous effluent and liquid effluent mixture has the advantage of extracting not only the contaminants from the gaseous effluent, but also the hydrogen halides (HCl) dissolved in the liquid effluent. Indeed, the hydrogen halides dissolved in the liquid effluent from step b) are released and also form ammonium halides with the ammonia present in the gaseous effluent.

[0140] Washing with an aqueous solution in this step c) allows these salts to be dissolved in the aqueous effluent. This produces a hydrocarbon effluent freed from halides, a gaseous effluent freed from halides and an aqueous effluent in which the ammonium halide salts are dissolved.

[0141] The temperature at which the separation of step c) is carried out must be lower than the precipitation temperature of the ammonium halides in order to precipitate the ammonium halide salts. The temperature at which the separation of step c) is carried out is greater than or equal to 20°C and less than 200°C, preferably between 25 and 120°C, and particularly preferably between 30 and 70°C.

[0142] The term "pressure substantially equal to the pressure of step b)" means the pressure of step b) with a pressure difference of between 0 and 1 MPa, preferably of between 0.005 and 0.3 Mpa, and particularly preferably of between 0.01 and 0.3 Mpa relative to the pressure of step b). Preferably, the pressure of step c) is the pressure of step b) less the pressure losses. The fact of operating at least part of the separation step c) at a pressure substantially identical to the operating pressure of step b) also facilitates the recycling of hydrogen contained in the gaseous effluent.

[0143] Separation step c) may also be carried out at a pressure lower than the pressure of step b). Separation step c) may also comprise a (first) separation step at a pressure substantially equal to the operating pressure of step b), followed by at least one further separation step carried out at the same or lower temperature and at a lower pressure than each separation step of the preceding step c).

[0144] Separation step c) can advantageously be implemented by any method known to those skilled in the art such as, for example, the combination of one or more separator(s) (balloon(s)), and / or one or more stripping column(s), this or these separator(s) (balloon(s)) and / or columns optionally being able to be supplied with a stripping gas, for example a hydrogen-rich gas stream. Preferably, step c) is implemented with a single separator (balloon).

[0145] Separation step c) is preferably carried out in at least one so-called high pressure or medium pressure low temperature separator tank, also known to those skilled in the art as CHPS (for “Cold High Pressure Separator” in English terminology). Thus, this step c) preferably uses a so-called “cold high pressure” separator, the pressure being substantially equal to the operating pressure of step b).

[0146] The washing / separation section of step c) may at least partly be carried out in common or separate washing and separation equipment, this equipment being well known (separator drums which can operate at different pressures and temperatures, pumps, heat exchangers, washing columns, etc.). The separation step c) may for example comprise a column for stripping acid water (also called a "sour water stripper" according to English terminology) from the withdrawn aqueous effluent, an acid gas washing column to purify the hydrogen-rich gas before recycling, a column for stabilizing the washed liquid effluent to remove the dissolved gases.

[0147] The gaseous effluent obtained at the end of step c) advantageously comprises hydrogen, preferably comprises at least 80% by volume, preferably at least 85% by volume, of hydrogen. Advantageously, said gaseous effluent can at least partly be recycled to steps a) of hydrogenation and / or d) of hydrotreatment and / or to one or more steps f) of hydrocracking when they are present, the recycling system being able to comprise a purification section.

[0148] The gaseous effluent may also be subject to additional separation(s) in order to recover at least one hydrogen-rich gas and / or light hydrocarbons, in particular ethane, propane and butane, which may advantageously be sent separately or as a mixture to one or more furnaces of steam cracking step g) so as to increase the overall yield of olefins. The aqueous effluent obtained at the end of step c) advantageously comprises dissolved ammonium salts and / or hydrogen halides (for example hydrochloric acid).

[0149] Depending on the content of halogenated compounds in the initial feedstock to be treated, a stream containing an amine such as, for example, monoethanolamine, diethanolamine and / or monodiethanolamine may be injected upstream of hydrogenation step a) in order to ensure a sufficient quantity of ammonium ions to combine the halide ions formed during the hydrogenation step, thus limiting the formation of hydrochloric acid and thus limiting corrosion downstream of the separation section. This injection may be necessary in particular when the feedstock contains a lot of halogenated compounds or few nitrogen compounds, or when the HDN of the nitrogen compounds is not sufficiently advanced during step a) in order to form enough gaseous ammonia or ammonium ions.

[0150] In a possible embodiment of the invention, separation step c) comprises the injection of an aqueous solution into the mixture of the gaseous effluent and another part of the liquid effluent from step b), followed by the washing / separation section advantageously comprising a separation phase making it possible to obtain at least one aqueous effluent loaded with dissolved ammonium halide salts, a washed liquid hydrocarbon effluent and a partially washed gaseous effluent. The aqueous effluent loaded with dissolved ammonium halide salts and the washed liquid hydrocarbon effluent can then be separated in a settling tank in order to obtain said hydrocarbon effluent and said aqueous effluent.Said partially washed gaseous effluent may in parallel be introduced into a washing column where it circulates countercurrently to an aqueous stream, preferably of the same nature as the aqueous solution injected into the hydrocarbon effluent, which makes it possible to eliminate at least in part, preferably in full, hydrogen halides (of the HCl type) contained in the partially washed gaseous effluent and thus to obtain said gaseous effluent, preferably essentially comprising hydrogen, and an acidic aqueous stream. Said aqueous effluent from the settling tank may optionally be mixed with said acidic aqueous stream, and be used, optionally in a mixture with said acidic aqueous stream in a water recycling circuit to supply step c) of separation into said aqueous solution upstream of the washing / separation section and / or into said aqueous stream in the washing column.Said water recycling circuit may include a water top-up and / or a basic solution and / or a purge to remove dissolved salts.

[0151] The hydrocarbon effluent from separation step c) is sent, in part or in full, to hydrotreatment step d). (d) Hydrotreatment step

[0152] According to the invention, the treatment method comprises a hydrotreatment step d) implemented in a hydrotreatment reaction section, implementing at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrotreatment catalyst, said hydrotreatment reaction section being fed at least by said hydrocarbon effluent from step c), optionally by at least a portion of the liquid effluent from step b), and a second gas stream comprising hydrogen, said hydrotreatment reaction section being implemented at an average temperature between 250 and 430°C, a partial pressure of hydrogen between 1.0 and 10.0 MPa abs. and an hourly volumetric velocity between 0.1 and 10.0 h' 1 , to obtain a hydrotreated effluent.

[0153] Advantageously, step d) implements hydrotreatment reactions well known to those skilled in the art, and more particularly hydrotreatment reactions such as the hydrogenation of aromatics, hydrodesulfurization and hydrodenitrogenation. In addition, the hydrogenation of the remaining olefins and halogenated compounds as well as the hydrodemetalation can continue even if the majority and preferably all of these impurities have been removed during step a).

[0154] Said hydrotreatment reaction section is advantageously carried out at a pressure equivalent to that used in the reaction section of hydrogenation step a), and generally at a higher average temperature than that of the reaction section of hydrogenation step a). Thus, said hydrotreatment reaction section is advantageously carried out at an average hydrotreatment temperature between 250 and 430°C, preferably between 280 and 380°C, at a hydrogen partial pressure between 1.0 and 10.0 MPa abs. and at an hourly volumetric flow rate (WH) between 0.1 and 10.0 h' 1 , preferably between 0.1 and 5.0 h' 1 , preferably between 0.2 and 2.0 h' 1 , preferably between 0.2 and 1h' 1 The hydrogen coverage in step d) is advantageously between 100 and 1500 Nm 3 of hydrogen per m 3of fresh charge which feeds step a), and preferably between 200 and 1000 Nm 3 of hydrogen per m 3 of fresh charge which feeds step a), preferably between 250 and 800 Nm 3 of hydrogen per m 3 of fresh feedstock which feeds step a). The definitions of the average temperature (WABT), the WH and the hydrogen coverage correspond to those described above. Said hydrotreatment reaction section is fed at least by said hydrocarbon effluent from step c) and a second gaseous stream comprising hydrogen, advantageously at the level of the first catalytic bed of the first reactor in operation.

[0155] Optionally, the reaction section of said step d) may also be additionally supplied with at least part of the liquid effluent from step b). This has the advantage of saving energy because the liquid effluent from step b) is hot and does not need to be reheated before its introduction into step d).

[0156] According to another (preferred) variant and when the cold separation step c) is fed with the gaseous effluent mixture and at least part, and preferably all, of the liquid effluent from step b), the reaction section of said step d) is fed only with said hydrocarbon effluent from step c).

[0157] Advantageously, said step d) is carried out in a hydrotreatment reaction section comprising at least one, preferably between one and five, fixed-bed reactor(s) having n catalytic beds, n being an integer greater than or equal to one, preferably between one and ten, preferably between two and five, said bed(s) each comprising at least one, and preferably not more than ten, hydrotreatment catalyst(s). When a reactor comprises several catalytic beds, i.e. at least two, preferably between two and ten, preferably between two and five catalytic beds, said catalytic beds are preferably arranged in series in said reactor.

[0158] When step d) is implemented in a hydrotreatment reaction section comprising several, preferably two, reactors, these reactors can operate in series and / or in parallel and / or in permutable mode (or PRS) and / or in “swing” mode. The various possible operating modes, PRS mode (or lead and lag) and swing mode, are well known to those skilled in the art and are advantageously defined above.

[0159] In another embodiment of the invention, said hydrotreatment reaction section comprises a single fixed bed reactor containing n catalytic beds, n being an integer greater than or equal to one, preferably between one and ten, more preferably between two and five.

[0160] In a particularly preferred embodiment, the hydrogenation reaction section of step a) comprises two reactors operating in permutable mode followed by the hydrotreatment reaction section of step d) which comprises a single fixed-bed reactor. Advantageously, said hydrotreatment catalyst used in said step d) may be chosen from known hydrodemetallization, hydrotreatment, silicon capture catalysts, used in particular for the treatment of petroleum fractions, and combinations thereof. Known hydrodemetallization catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 5221656, US 5827421, US 7119045, US 5622616 and US 5089463. Known hydrotreatment catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 6589908, US 4818743 or US 6332976.Known silicon capture catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0161] In particular, said hydrotreatment catalyst comprises a support, preferably mineral, and at least one metallic element having a hydro-dehydrogenating function. Said metallic element having a hydro-dehydrogenating function advantageously comprises at least one element from group VIII, preferably chosen from the group consisting of nickel and cobalt, and / or at least one element from group VI B, preferably chosen from the group consisting of molybdenum and tungsten. The total content expressed as oxides of the metallic elements from groups VI B and VIII is preferably between 0.1% and 40% by weight, preferably from 5% to 35% by weight, relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MoOa and WO3 respectively.The weight ratio expressed as metal oxide between the metal (or metals) of group VIB relative to the metal (or metals) of group VIII is preferably between 1.0 and 20, preferably between 2.0 and 10. For example, the hydrotreatment reaction section of step d) of the process comprises a hydrotreatment catalyst comprising between 0.5% and 10% by weight of nickel, preferably between 1% and 8% by weight of nickel, expressed as nickel oxide NiO relative to the total weight of the hydrotreatment catalyst, and between 1.0% and 30% by weight of molybdenum, preferably between 3.0% and 29% by weight of molybdenum, expressed as molybdenum oxide MoOs relative to the total weight of the hydrotreatment catalyst, on a mineral support, preferably on an alumina support.

[0162] The support of said hydrotreatment catalyst is advantageously chosen from alumina, silica, silica-aluminas, magnesia, clays and mixtures thereof. Said support may also contain doping compounds, in particular oxides chosen from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphoric anhydride and a mixture of these oxides. Preferably, said hydrotreatment catalyst comprises an alumina support, preferably an alumina support doped with phosphorus and optionally boron. When phosphoric anhydride P2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina.When boron trioxide B2O3 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% relative to the total weight of the alumina. The alumina used may be, for example, a γ (gamma) or (eta) alumina.

[0163] Said hydrotreatment catalyst is for example in the form of extrudates.

[0164] Advantageously, said hydrotreatment catalyst of the process has a specific surface area greater than or equal to 250 m 2 / g, preferably greater than or equal to 300 m 2 / g. The specific surface area of ​​said hydrotreatment catalyst is advantageously less than or equal to 800 m 2 / g, preferably less than or equal to 600 m 2 / g, in particular less than or equal to 400 m 2 / g. The specific surface area of ​​the hydrotreatment catalyst is measured by the BET method, i.e. the specific surface area determined by nitrogen adsorption in accordance with ASTM D 3663-78 based on the BRUNAUER-EMMETT-TELLER method described in the periodical 'The Journal of the American Chemical Society", 6Q, 309 (1938). Such a specific surface area allows for further improvement in the removal of contaminants, particularly metals such as silicon.

[0165] According to another aspect of the invention, the hydrotreatment catalyst as described above further comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such a catalyst is often referred to as an "additive catalyst". Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide or compounds including a furan cycle or sugars.

[0166] Preferably, step d) can implement upstream of the hydrogenation catalyst(s) at least one guard bed or a series of guard beds of the “grading” type as described above for step a).

[0167] Advantageously, hydrotreatment step d) allows the hydrogenation of at least 80%, and preferably of all of the olefins and halogenated compounds remaining after hydrogenation step a), but also the conversion at least in part of other impurities present in the feedstock, such as aromatic compounds, metallic compounds, sulfur compounds, nitrogen compounds, oxygenated compounds. Preferably, the nitrogen content at the outlet of step d) is less than 100 ppm by weight, and preferably less than 10 ppm by weight. Preferably, the sulfur content at the outlet of step d) is less than 100 ppm by weight, and preferably less than 10 ppm by weight. Step d) can also make it possible to further reduce the contaminant content, such as that of metals, in particular the silicon content.Preferably, the metal content at the outlet of step d) is less than 10 ppm by weight, and preferably less than 2 ppm by weight, and the silicon content is less than 5 ppm by weight. Preferably, the halogen element content at the outlet of step d) is less than 5 ppm by weight.

[0168] Depending on the content of sulfur compounds in the initial feedstock to be treated, a stream containing a sulfurizing agent may be injected upstream of hydrogenation step a) and / or hydrotreatment step d) and / or upstream of one of the hydrocracking steps when they are present, preferably upstream of hydrogenation step a) and / or hydrotreatment step d) in order to ensure a sufficient quantity of sulfur to form or maintain the active species of the catalyst (in sulfur form). This activation or sulfurization step is carried out by methods well known to those skilled in the art, and advantageously under a sulfide-reducing atmosphere in the presence of hydrogen and hydrogen sulfide.The sulfurizing agents are preferably H2S gas, elemental sulfur, CS2, mercaptans, sulfides and / or polysulfides, hydrocarbon fractions with a boiling point below 400°C containing sulfur compounds or any other compound containing sulfur used for the activation of hydrocarbon feedstocks in order to sulfurize the catalyst. Said sulfur-containing compounds are advantageously chosen from alkyl disulfides such as, for example, dimethyl disulfide (DMDS), alkyl sulfides, such as, for example, dimethyl sulfide, thiols such as, for example, n-butyl mercaptan (or 1-butanethiol) and polysulfide compounds of the tert-onylpolysulfide type. The catalyst may also be sulfurized by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfurized in situ in the presence of a sulfurizing agent and a hydrocarbon feedstock.Very preferably, the catalyst is sulfurized in situ in the presence of the additive charge of dimethyl disulfide.

[0169] The hydrotreated effluent from hydrotreatment step d) may be sent, in part or in full, either to a fractionation step e), or directly to a hydrocracking step f), or directly to a steam cracking step g), or directly to a fuel storage unit.

[0170] Sending the hydrotreated effluent from hydrotreatment step d) directly to a hydrocracking step has the advantage of not having to repressurize it. According to another variant, the hydrotreated effluent can undergo a hot separation step followed by a cold separation step with washing in the same way as steps b) and c) described above. This variant is advantageous for feeds heavily loaded with halogenated compounds, and in particular chlorinated compounds. The hydrocarbon effluent leaving the cold separation with washing can then be sent, in part or in full, either to a fractionation step e), or directly to a hydrocracking step f), or directly to a steam cracking step g), or directly to a fuel storage unit.

[0171] Advantageously, a pump can be used between separation step c) and hydrotreatment step d) so as to raise the total pressure at the inlet of d).

[0172] Advantageously, an additional hydrogen flow can be injected at the inlet of hydrotreatment step d) so as to adjust the hydrogen partial pressure.

[0173] (e) Splitting step (optional)

[0174] The process according to the invention may comprise a step of fractionating all or part, preferably all, of the hydrotreated effluent from step d), to obtain at least a third gas stream, a naphtha cut and at least one middle distillate cut.

[0175] The term "naphtha cut" means a hydrocarbon cut comprising compounds having a boiling point generally less than or equal to 175°C, in particular between 80 and 175°C.

[0176] The term "middle distillate cut" refers to a hydrocarbon cut comprising compounds with a boiling point generally above 175°C. The heavy cut may include middle distillates such as a diesel cut and / or a kerosene cut. It may also include heavier compounds.

[0177] Depending on the destination or use of the cuts from fractionation step e), the person skilled in the art will adjust the cut points in the stripping and / or distillation operations. For example, it may be necessary to adjust the end point of the naphtha cut to 150, 175 or 200°C.

[0178] Step e) makes it possible in particular to eliminate gases dissolved in the hydrotreated liquid effluent, such as for example ammonia, hydrogen sulfide and light hydrocarbons having 1 to 4 carbon atoms.

[0179] The optional fractionation step e) is advantageously carried out at a pressure less than or equal to 1.0 MPa abs., preferably between 0.1 and 1.0 MPa abs. According to one embodiment, step e) can be carried out in a section advantageously comprising at least one stripping column equipped with a reflux circuit comprising a reflux drum. Said stripping column is fed with the hydrotreated liquid effluent from step d) and with a stream of water vapor. The hydrotreated liquid effluent from step d) can optionally be reheated before entering the stripping column. Thus, the lightest compounds are entrained at the top of the column and into the reflux circuit comprising a reflux drum in which a gas / liquid separation takes place. The gaseous phase which comprises the light hydrocarbons is withdrawn from the reflux drum, in a gaseous stream. The naphtha cut is advantageously withdrawn from the reflux drum, in liquid flow.The middle distillate cut is advantageously withdrawn at the bottom of the stripping column.

[0180] According to another embodiment, step e) can be carried out in a section comprising one or more separator tank(s). Advantageously, at least one so-called low-pressure, low-temperature separator tank will be used in order to eliminate the gases dissolved in the hydrotreated liquid effluent.

[0181] According to other embodiments, fractionation step e) may implement a stripping column or a balloon separator followed by a distillation column or only a distillation column.

[0182] The naphtha cut and the middle distillate cut, optionally mixed, may be sent, in whole or in part, to a steam cracking unit, at the end of which olefins may be (re)formed to participate in the formation of polymers. Preferably, only a portion of said cuts is sent to a steam cracking unit; at least a fraction of the remaining portion is optionally recycled in at least one of the steps of the process and / or sent to a fuel storage unit, for example a naphtha storage unit, a diesel storage unit or a kerosene storage unit, derived from conventional petroleum feedstocks.

[0183] According to a preferred embodiment, the naphtha cut, all or part, is sent to a steam cracking unit, while the middle distillate cut is sent to a hydrocracking step f) and / or sent to a fuel storage unit.

[0184] In a particular embodiment, the optional fractionation step e) can make it possible to obtain, in addition to a gas stream, a naphtha cut (generally comprising compounds having a boiling point less than or equal to 175°C, preferably between 80 and 175°C), and a middle distillate cut (generally comprising compounds having a boiling point greater than 175°C and less than 385°C), and a heavy hydrocarbon cut (generally comprising compounds having a boiling point greater than or equal to 385°C).The naphtha cut may be sent, in whole or in part, to a steam cracking unit and / or to the naphtha storage unit from conventional petroleum feedstocks, it may still be recycled; the middle distillate cut may also be, in whole or in part, either sent to a steam cracking unit, or to a diesel storage unit from conventional petroleum feedstocks, or to the hydrocracking stage f) when it is present, or still be recycled; the heavy cut may, for its part, be sent, at least in part, to a steam cracking unit, or be sent to the hydrocracking stage when it is present.

[0185] In another particular embodiment, the optional fractionation step e) can make it possible to obtain, in addition to a gas stream, a naphtha cut (generally comprising compounds having a boiling point less than or equal to 175°C, preferably between 80 and 175°C), and a kerosene cut (generally comprising compounds having a boiling point greater than 175°C and less than or equal to 280°C), a diesel cut (generally comprising compounds having a boiling point greater than 280°C and less than 385°C) and a heavy hydrocarbon cut (generally comprising compounds having a boiling point greater than or equal to 385°C). The naphtha cut, the kerosene cut and / or the diesel cut may be, in whole or in part, either sent to a steam cracking unit, or respectively to a naphtha, kerosene or diesel pool from conventional petroleum feedstocks, or recycled.Diesel and / or kerosene cuts can also be sent to hydrocracking step f) when present. The heavy cut can be sent, at least in part, to a steam cracking unit, or be sent to hydrocracking step f) when present.

[0186] In another particular embodiment, the naphtha cut from step e) is split into a heavy naphtha cut (generally comprising compounds having a boiling point between 80 and 175°C) and a light naphtha cut (generally comprising compounds having a boiling point below 80°C), at least a portion of said heavy naphtha cut being sent to an aromatic complex comprising at least one naphtha reforming step in order to produce aromatic compounds. According to this embodiment, at least a portion of the light naphtha cut is sent to the steam cracking step g) described below.

[0187] The gaseous effluent(s) from fractionation step e) may be subject to additional purification(s) and separation(s) in order to recover at least light hydrocarbons, in particular ethane, propane and butane, which may advantageously be sent separately or as a mixture to one or more furnaces of steam cracking step g) so as to increase the overall yield of olefins.

[0188] (f) Hydrocracking step (optional)

[0189] According to a variant, the process of the invention may comprise a hydrocracking step f) carried out after the hydrotreatment step d) with at least a portion of said hydrotreated effluent from step d) or carried out after the fractionation step e) with at least a portion of the middle distillate cut.

[0190] Advantageously, step f) implements the hydrocracking reactions well known to those skilled in the art, and more particularly makes it possible to convert heavy compounds, for example compounds having a boiling point above 175°C into compounds having a boiling point less than or equal to 175°C. Other reactions, such as the hydrogenation of olefins, aromatics, hydrodemetallation, hydrodesulfurization, hydrodenitrogenation, etc. can continue.

[0191] Compounds with a boiling point above 175°C contain more naphthenic, naphtheno-aromatic, and aromatic compounds than lighter compounds, leading to a higher C / H ratio. This high ratio causes coking in the steam cracker, requiring steam cracking furnaces dedicated to this cut. When the yield of these heavy compounds (middle distillate cut) is minimized and the yield of light compounds (naphtha cut) is maximized, these compounds can be converted at least partially into light compounds by hydrocracking, a cut generally favored for a steam cracking unit.

[0192] Thus, the process of the invention may comprise a hydrocracking step f) implemented in a hydrocracking reaction section, implementing at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of said hydrotreated effluent from step d) and / or with at least a portion of the middle distillate cut from step e) and a third gas stream comprising hydrogen, said hydrocracking reaction section being implemented at an average temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 MPa abs. and an hourly volumetric velocity between 0.1 and 10.0 h -1 to obtain a first hydrocracked effluent.

[0193] Thus, said hydrocracking reaction section is advantageously carried out at an average temperature between 250 and 480°C, preferably between 320 and 450°C, at a hydrogen partial pressure between 1.5 and 20.0 Mpa abs., preferably between 3 and 18.0 Mpa abs., and at an hourly volumetric flow rate (WH) between 0.1 and 10.0 h -1 , preferably between 0.1 and 5.0 h' 1 , preferably between 0.2 and 4 h -1 The hydrogen coverage in step f) is advantageously between 80 and 2000 Nm 3 of hydrogen per m 3 of fresh charge which feeds step f), and preferably between 200 and 1800 Nm 3 of hydrogen per m 3 of fresh charge that feeds stage f). The definitions of average temperature (WABT), WH and hydrogen coverage correspond to those described above.

[0194] Advantageously, said hydrocracking reaction section is implemented at a pressure equivalent to that used in the reaction section of hydrogenation step a) or hydrotreatment step d).

[0195] Advantageously, said step f) is carried out in a hydrocracking reaction section comprising at least one, preferably between one and five, fixed bed reactor(s) having n catalytic beds, n being an integer greater than or equal to one, preferably between one and ten, preferably between two and five, said bed(s) each comprising at least one, and preferably not more than ten, hydrocracking catalyst(s). When a reactor comprises several catalytic beds, i.e. at least two, preferably between two and ten, preferably between two and five catalytic beds, said catalytic beds are preferably arranged in series in said reactor.

[0196] The hydrocracked effluent can at least partly be recycled into step a) of hydrogenation and / or into step b) of hot separation and / or into step c) of hot separation and / or into step d) of hydrotreatment and / or into step e) of fractionation.

[0197] The hydrocracking step can be carried out in one (step f) or two steps (step f) and f')). When it is carried out in two steps, a separation of the effluent from the first hydrocracking step f) is carried out, making it possible to obtain a hydrocarbon cut comprising compounds having a boiling point above 175°C (middle distillate cut), which is introduced into the second hydrocracking step f') comprising a second dedicated hydrocracking reaction section, different from the first hydrocracking reaction section f). This configuration is particularly suitable when it is desired to produce only a naphtha cut.

[0198] The second hydrocracking step f') implemented in a hydrocracking reaction section, implementing at least one fixed bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of the first hydrocracking effluent from the first hydrocracking step f) and a gas stream comprising hydrogen, said hydrocracking reaction section being implemented at an average temperature between 250 and 450°C, a partial pressure of hydrogen between 1.5 and 20.0 Mpa abs. and an hourly volumetric velocity between 0.1 and 10.0 IT 1, to obtain a second hydrocracked effluent. The preferred operating conditions and catalysts used in the second hydrocracking stage are those described for the first hydrocracking stage. The operating conditions and catalysts used in the two hydrocracking stages may be the same or different.

[0199] Said second hydrocracking step is preferably carried out in a hydrocracking reaction section comprising at least one, preferably between one and five, fixed bed reactor(s) having n catalytic beds, n being an integer greater than or equal to one, preferably between one and ten, more preferably between two and five, said bed(s) each comprising at least one, and preferably not more than ten, hydrocracking catalyst(s).

[0200] These operating conditions used in the hydrocracking step(s) generally make it possible to achieve conversions per pass, into products having at least 80% by volume of compounds having boiling points less than or equal to 175°C, preferably less than 160°C and more preferably less than 150°C, and greater than 15% by weight and even more preferably between 20 and 95% by weight. When the process is carried out in two hydrocracking stages, the conversion per pass in the second stage is kept moderate in order to maximize the selectivity into compounds of the naphtha cut (having a boiling point less than or equal to 175°C, in particular between 80 and less than or equal to 175°C). The conversion per pass is limited by the use of a high recycle rate on the loop of the second hydrocracking stage.This rate is defined as the ratio between the feed flow rate of step f') and the flow rate of the feed of step a), preferably this ratio is between 0.2 and 4, preferably between 0.5 and 2.5.

[0201] The hydrocracked effluent from the second hydrocracking stage f') can at least partly be recycled into the hydrogenation stage a) and / or into the hot separation stage b) and / or into the hot separation stage c) and / or into the hydrotreatment stage d) and / or into the fractionation stage e).

[0202] The hydrocracking step(s) thus do not necessarily allow all the hydrocarbon compounds of the middle distillate cut to be transformed into hydrocarbon compounds having a boiling point less than or equal to 175°C (naphtha cut). After the fractionation step e), there may therefore remain a more or less significant proportion of compounds having a boiling point above 175°C. At least a portion of this unconverted cut may be introduced into a second hydrocracking step f'). Another portion may be purged. Depending on the operating conditions of the process, said purge may be between 0 and 10% by weight of the cut comprising compounds having a boiling point above 175°C relative to the incoming feed, and preferably between 0.5% and 5% by weight.

[0203] According to the invention, the hydrocracking step(s) operate in the presence of at least one hydrocracking catalyst.

[0204] The hydrocracking catalyst(s) used in the hydrocracking step(s) are conventional hydrocracking catalysts known to those skilled in the art, of the bifunctional type combining an acid function with a hydro-dehydrogenating function and optionally at least one binding matrix. The acid function is provided by supports with a large surface area (150 to 800 m 2 / g generally) with surface acidity, such as halogenated aluminas (chlorinated or fluorinated in particular), combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites. The hydro-dehydrogenating function is provided by at least one metal from group VI B of the periodic table and / or at least one metal from group VIII.

[0205] Preferably, the hydrocracking catalyst(s) comprise a hydro-dehydrogenating function comprising at least one metal from group VIII chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, and preferably from cobalt and nickel. Preferably, said catalyst(s) also comprise at least one metal from group VI B chosen from chromium, molybdenum and tungsten, alone or as a mixture, and preferably from molybdenum and tungsten. Hydro-dehydrogenating functions of the NiMo, NiMoW, NiW type are preferred.

[0206] Preferably, the content of group VIII metal in the hydrocracking catalyst(s) is advantageously between 0.5 and 15% by weight and preferably between 1 and 10% by weight, the percentages being expressed as a percentage by weight of oxides relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO respectively.

[0207] Preferably, the content of group VI B metal in the hydrocracking catalyst(s) is advantageously between 5 and 35% by weight, and preferably between 10 and 30% by weight, the percentages being expressed as a percentage by weight of oxides relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is expressed as MoOa and WO3 respectively.

[0208] The hydrocracking catalyst(s) may also optionally comprise at least one promoter element deposited on the catalyst and selected from the group formed by phosphorus, boron and silicon, optionally at least one element from group VI IA (chlorine, fluorine preferred), optionally at least one element from group VI IB (manganese preferred), and optionally at least one element from group VB (niobium preferred).

[0209] Preferably, the hydrocracking catalyst(s) comprise at least one amorphous or poorly crystallized porous mineral matrix of oxide type chosen from aluminas, silicas, silica-aluminas, aluminates, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide, clay, alone or as a mixture, and preferably aluminas or silica-aluminas, alone or as a mixture.

[0210] Preferably, the silica-alumina contains more than 50% by weight of alumina, preferably more than 60% by weight of alumina.

[0211] Preferably, the hydrocracking catalyst(s) also optionally comprise a zeolite chosen from Y zeolites, preferably from USY zeolites, alone or in combination, with other zeolites from beta zeolites, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48, ZBM-30, alone or as a mixture. Preferably, the zeolite is USY zeolite alone.

[0212] In the case where said catalyst comprises a zeolite, the zeolite content in the hydrocracking catalyst(s) is advantageously between 0.1 and 80% by weight, preferably between 3 and 70% by weight, the percentages being expressed as a percentage of zeolite relative to the total weight of the catalyst.

[0213] A preferred catalyst comprises, and preferably consists of, at least one Group VI B metal and optionally at least one non-noble Group VIII metal, at least one promoter element, and preferably phosphorus, at least one Y zeolite and at least one alumina binder.

[0214] An even more preferred catalyst comprises, and preferably consists of, nickel, molybdenum, phosphorus, a USY zeolite, and optionally also a beta zeolite, and alumina.

[0215] Another preferred catalyst comprises, and preferably consists of, nickel, tungsten, alumina and silica-alumina.

[0216] Another preferred catalyst comprises, and preferably consists of, nickel, tungsten, USY zeolite, alumina and silica-alumina.

[0217] Said hydrocracking catalyst is for example in the form of extrudates. In a variant, the hydrocracking catalyst used in the second hydrocracking step comprises a hydro-dehydrogenating function comprising at least one noble metal from group VIII chosen from palladium and platinum, alone or as a mixture. The content of noble metal from group VIII is advantageously between 0.01 and 5% by weight and preferably between 0.05 and 3% by weight, the percentages being expressed as a percentage by weight of oxides (PtO or PdO) relative to the total weight of the catalyst.

[0218] According to another aspect of the invention, the hydrocracking catalyst further comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such a catalyst is often referred to as an "additive catalyst". Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide or compounds including a furan cycle or sugars.

[0219] The preparation of catalysts for the hydrogenation, hydrotreatment and hydrocracking stages is known and generally comprises a step of impregnation of the metals of group VIII and group VI B when present, and possibly phosphorus and / or boron on the support, followed by drying, then possibly calcination. In the case of an additive catalyst, the preparation is generally carried out by simple drying without calcination after introduction of the organic compound. Calcination here means a heat treatment under a gas containing air or oxygen at a temperature greater than or equal to 200°C. Before their use in a stage of the process, the catalysts are generally subjected to sulfurization in order to form the active species. The catalyst of stage a) can also be a catalyst used in its reduced form, thus involving a reduction stage in its preparation.

[0220] The gas stream comprising hydrogen, which feeds the hydrogenation, hydrotreatment and optionally hydrocracking reaction section, may consist of a hydrogen make-up and / or recycled hydrogen originating in particular from separation step c) or from fractionation step e) if this step is implemented. Preferably, an additional gas stream comprising hydrogen is advantageously introduced at the inlet of each reactor, in particular operating in series, and / or at the inlet of each catalytic bed from the second catalytic bed of the reaction section. These additional gas streams are also called cooling streams. They make it possible to control the temperature in the reactor in which the reactions carried out are generally very exothermic.Said hydrotreated effluent or said hydrocarbon fraction(s) thus obtained by treatment according to the process of the invention of a pyrolysis oil, has(have) a composition compatible with the specifications of an input feedstock of a steam cracking unit. In particular, the composition of the hydrotreated effluent or said hydrocarbon fraction(s) is preferably such that:.

[0221] - the total content of metallic elements is less than or equal to 10.0 ppm by weight, preferably less than or equal to 2.0 ppm by weight, preferentially less than or equal to 1.0 ppm by weight and preferably less than or equal to 0.8 ppm by weight, with: a content of silicon element (Si) less than or equal to 5.0 ppm by weight, preferably less than or equal to 1 ppm by weight, and preferably less than or equal to 0.6 ppm by weight and a content of iron element (Fe) less than or equal to 200 ppb by weight,

[0222] - the sulfur content is less than or equal to 500 ppm by weight, preferably less than or equal to 200 ppm by weight,

[0223] - the nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight and more preferably less than or equal to 5 ppm by weight

[0224] - the total chlorine element content is less than or equal to 5.0 ppm by weight, preferably less than 1.0 ppm by weight,

[0225] - the content of olefinic compounds (mono- and di-olefins) is less than or equal to 5.0% by weight, preferably less than or equal to 2.0% by weight, more preferably less than or equal to 0.1% by weight.

[0226] - the mercury content is less than or equal to 5 ppb by weight, preferably less than 3 ppb by weight.

[0227] The contents are given in relative weight concentrations, percentage (%) by weight, part(s) per million (ppm) by weight or part(s) per billion (ppb) by weight, relative to the total weight of the stream considered.

[0228] The process according to the invention therefore makes it possible to treat pyrolysis oils to obtain at least one effluent which can be injected, in whole or in part, into at least one steam cracking unit.

[0229] Heavy metal adsorption step (optional)

[0230] Any gaseous effluent and / or any liquid effluent from at least one of the separation steps b) and c) or from the fractionation step e) may be subjected to an optional heavy metal adsorption step. The gaseous effluents are in particular the first gaseous effluent from step b) and / or the second gaseous effluent from step c) and / or the third gaseous effluent from step e).

[0231] The liquid effluents are in particular the liquid effluent from step b) and / or the hydrocarbon effluent from step c) and / or at least one of the cuts from step e).

[0232] The optional adsorption step makes it possible to eliminate or reduce the quantity of metallic impurities, in particular the quantity of heavy metals such as arsenic, zinc, lead, and in particular mercury, possibly present in said gaseous and liquid effluents. The metallic impurities may be present in the feedstock and / or form during the process steps. Their elimination or reduction may in particular be necessary when at least part of said gaseous and liquid effluents is intended to be sent to a steam cracking step, either directly or after having undergone one or more optional additional steps such as the fractionation step e). The specifications for metallic impurities at the inlet of the steam cracking step, in particular mercury, may require such a step.

[0233] Thus, an optional step of adsorption of a gaseous effluent from steps b), c) and / or e) and / or the liquid effluent from step b) and / or the hydrocarbon effluent from step c) and / or at least one of the cuts from step e) is advantageously carried out in particular when at least one of these effluents or the feed respectively comprises more than 20 ppb by weight, in particular more than 15 ppm by weight of heavy metal elements (As, Zn, Pb, Hg, etc.), and in particular when at least one of these effluents or the feed respectively comprises more than 10 ppm by weight of mercury, more particularly more than 15 ppm by weight of mercury.

[0234] Said optional adsorption step is advantageously carried out at a temperature between 20 and 150°C, preferably between 40 and 100°C, and at a pressure between 0.15 and 10.0 Mpa abs, preferably between 0.2 and 1.0 Mpa abs.

[0235] Said optional adsorption step can be implemented by any adsorbent known to those skilled in the art making it possible to reduce the quantity of such contaminants.

[0236] According to a variant, said optional adsorption step is implemented in an adsorption section operated in the presence of at least one adsorbent comprising a porous support and at least one active phase based on sulfur in the elemental form or in the form of metal sulfide. The porous support can be chosen indifferently from the families of aluminas, silica-aluminas, silicas, zeolites, activated carbons. Advantageously, the porous support is based on alumina. The specific surface area of ​​the support is generally between 150 and 600 m 2 / g, preferably between 200 and 400 m 2 / g, even more preferably between 150 and 320 m 2 / g. The specific surface area of ​​the adsorbent is a surface area measured by the BET method as described above.

[0237] The active phase is based on sulfur in elemental form or in the form of a metal sulfide, in particular a sulfide of a metal from the group chosen from copper, molybdenum, tungsten, iron, nickel or cobalt.

[0238] Advantageously, the active phase of the adsorbent comprises between 1 and 70% by weight of sulfur relative to the total weight of the adsorbent, preferably between 2 and 25% and very preferably between 3 and 20%. The proportion by weight of metal relative to the total weight of the adsorbent is generally between 1 and 60%, preferably between 2 and 40%, preferably between 5 and 30%, very preferably between 5 and 20%.

[0239] The residence time in the adsorption section is generally between 1 and 180 minutes.

[0240] Said adsorption section comprises at least one adsorption column, preferably comprises at least two adsorption columns, preferably between two and four adsorption columns, containing said adsorbent. When the adsorption section comprises two adsorption columns, one operating mode may be a so-called "swing" operation, in which one of the columns is online, i.e. in operation, while the other column is in reserve. Another operating mode is to have at least two columns operating in series in a switchable mode.

[0241] (g) Steam cracking step (optional)

[0242] The hydrotreated effluent from hydrotreatment step d), or at least one of the liquid hydrocarbon cuts from the optional step e), may be sent in whole or in part to a steam cracking step g).

[0243] Advantageously, the gaseous effluent(s) from separation step c) and / or fractionation step e) and containing ethane, propane and butane, may also be sent in whole or in part to steam cracking step g).

[0244] Said steam cracking step g) is advantageously carried out in at least one pyrolysis furnace at a temperature between 700 and 900°C, preferably between 750 and 850°C, and at a pressure between 0.05 and 0.3 MPa relative. The residence time of the hydrocarbon compounds is generally less than or equal to 1.0 seconds (denoted s), preferably between 0.1 and 0.5 s. Advantageously, water vapor is introduced upstream of the optional steam cracking step g) and after the separation (or fractionation). The quantity of water introduced, advantageously in the form of water vapor, is advantageously between 0.3 and 3.0 kg of water per kg of hydrocarbon compounds at the inlet of step g). Preferably, the optional step g) is carried out in several pyrolysis furnaces in parallel so as to adapt the operating conditions to the different flows feeding step g), in particular from step e), and also to manage the decoking times of the tubes.A furnace consists of one or more tubes arranged in parallel. A furnace can also refer to a group of furnaces operating in parallel. For example, one furnace may be dedicated to cracking the middle distillate cut.

[0245] The effluents from the various steam cracking furnaces are generally recombined before separation in order to constitute an effluent. It is understood that the steam cracking step g) comprises the steam cracking furnaces but also the sub-steps associated with steam cracking well known to those skilled in the art. These sub-steps may include in particular heat exchangers, columns and catalytic reactors and recycles to the furnaces. A column generally makes it possible to fractionate the effluent in order to recover at least a light fraction comprising hydrogen and compounds having 2 to 5 carbon atoms, and a fraction comprising pyrolysis gasoline, and possibly a heavier fraction. Columns make it possible to separate the different constituents of the light fractionation fraction in order to recover at least one cut rich in ethylene (C2 cut) and a cut rich in propylene (C3 cut) and possibly a cut rich in butenes (C4 cut).Catalytic reactors are used in particular to carry out hydrogenation of C2, C3 and even C4 cuts and pyrolysis gasoline. Saturated compounds, particularly saturated compounds with 2 to 4 carbon atoms, are advantageously recycled to steam cracking furnaces in order to increase overall olefin yields.

[0246] This steam cracking step g) makes it possible to obtain at least one effluent containing olefins comprising 2, 3 and / or 4 carbon atoms (i.e. C2, C3 and / or C4 olefins), at satisfactory contents, in particular greater than or equal to 30% by weight, in particular greater than or equal to 40% by weight, or even greater than or equal to 50% by weight of total olefins comprising 2, 3 and 4 carbon atoms relative to the weight of the steam cracking effluent in question. Said C2, C3 and C4 olefins can then be advantageously used as polyolefin monomers. Analysis methods used

[0247] The analysis methods and / or standards used to determine the characteristics of the various flows, in particular the load to be treated and the effluents, are known to those skilled in the art. They are listed below for information purposes. Other methods deemed equivalent may also be used, in particular equivalent IP, EN or ISO methods:

[0248] Table 1

[0249] (1) MAV method described in the article: C. Lôpez-Garcia et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil &

[0250] Gas Science and Technology - Rev. IFP, Vol. 62 (2007), No. 1, pp. 57-68. List of figures

[0251] The mention of the elements referenced in Figures 1 to 2 allows a better understanding of the invention, without it being limited to the particular embodiments illustrated in Figures 1 to 2. The different embodiments presented can be used alone or in combination with each other, without limitation of combination. In the figures, the same references designate identical or similar elements.

[0252] Figure 1 represents the diagram of a particular embodiment of the method of the present invention, comprising:

[0253] - a step a) of hydrogenation of a hydrocarbon feedstock resulting from the pyrolysis of plastics 1, preferably mixed with at least a portion of the recycled liquid effluent 7a resulting from step b) and in the presence of a hydrogen-rich gas 2 and optionally an amine supplied by the stream 3 and optionally a sulfur compound supplied by the stream 4, carried out in at least one fixed-bed reactor comprising at least one hydrogenation catalyst, to obtain a hydrogenated effluent 5;

[0254] - a step b) of separation of the hydrogenated effluent 5 carried out at high pressure and high temperature (HH PS) to obtain at least a first gaseous effluent 6, and a liquid effluent 7 of which a part 7a can be recycled upstream of step a),

[0255] - a separation step c) carried out at high pressure and low temperature (CH PS) and supplied with the first gaseous effluent 6 and the liquid effluent 7b from step b) and an aqueous solution 8 and making it possible to obtain at least a second gaseous effluent 9 comprising hydrogen, an aqueous effluent 10 containing dissolved salts, and a hydrocarbon effluent 11;

[0256] - a step d) of hydrotreatment of the hydrocarbon effluent 11 from step c), in the presence of hydrogen 12 carried out in at least one fixed-bed reactor comprising at least one hydrotreatment catalyst, to obtain a hydrotreated effluent 13;

[0257] - optionally a step e) of fractionation of the hydrotreated effluent 13 making it possible to obtain at least a third gaseous effluent 14, a naphtha cut 15 (generally comprising compounds having a boiling point less than or equal to 175°C) and a middle distillate cut 16 (generally comprising compounds having a boiling point greater than 175°C).

[0258] At the end of step e), a portion of the naphtha cut 15 may be sent to a steam cracking process (not shown). Another portion of the naphtha cut 15 may feed the hydrogenation step a) and / or the hydrotreatment step d) (not shown). Figure 2 represents the diagram of another particular embodiment of the process of the present invention which is based on the diagram of Figure 1. This diagram notably comprises a hydrocracking step f) in which at least a portion of the middle distillate cut 16 from step e) feeds this hydrocracking step f) which is carried out in at least one fixed-bed reactor comprising at least one hydrocracking catalyst and is supplied with hydrogen 17. The hydrocracked effluent 18 is recycled upstream of the separation step b).

[0259] Instead of injecting the amine stream 3 at the inlet of hydrogenation step a), it is possible to inject it at the inlet of hydrotreatment step d), at the inlet of separation step c), at the inlet of hydrocracking step f) when it is present, or even not to inject it, depending on the characteristics of the feedstock.

[0260] Only the main steps, with the main flows, are shown in Figures 1 and 2, in order to allow a better understanding of the invention. It is understood that all the equipment necessary for operation is present (tanks, pumps, exchangers, furnaces, columns, etc.), even if not shown. It is also understood that hydrogen-rich gas flows (make-up or recycle), as described above, can be injected at the inlet of each reactor or catalytic bed or between two reactors or two catalytic beds. Means well known to those skilled in the art for purifying and recycling hydrogen can also be implemented.

[0261] Examples

[0262] Example 1 is an example not in accordance with the invention without separation of the halogenated compounds between step a) of hydrogenation and step d) of hydrotreatment.

[0263] Example 2 is an example in accordance with the invention with separation of the halogenated compounds by the hot separation steps b) and cold separation steps c) between the hydrogenation step a) and the hydrotreatment step d).

[0264] Feed 1 treated in the process is a plastic pyrolysis oil (i.e. comprising 100% by weight of said plastic pyrolysis oil) having the characteristics indicated in Table 2. Table 2: Feed characteristics

[0265] Charge 1 is subjected to a hydrogenation step a) carried out in a fixed bed reactor and in the presence of hydrogen 2 and a NiMo on alumina type hydrogenation catalyst under the operating conditions indicated in table 4 making it possible to obtain a hydrogenated effluent 5.

[0266] At the end of hydrogenation step a), the conversion rates (= (initial concentration - final concentration) / initial concentration) observed are indicated in table 3. Table 3: conversions of species during hydrogenation step a) According to example 1 (non-compliant), the hydrogenated effluent 5 from hydrogenation step a) is subjected directly, without separation, to a hydrotreatment step d) carried out in a fixed bed and in the presence of hydrogen 12, and a NiMo-on-alumina hydrotreatment catalyst under the conditions presented in table 4. The hydrotreated effluent is then introduced into a so-called low-pressure separator drum at low temperature in order to remove the dissolved gases. The properties of the hydrotreated effluent, freed from dissolved gases, are presented in table 4 and comply with the specifications of a feedstock for a steam cracker.

[0267] According to example 2 (compliant), the hydrogenated effluent 5 from hydrogenation step a) is subjected to a separation step b) (hot) at a pressure substantially identical to that of step a) and the temperature of which is controlled at 300°C, making it possible to obtain a gaseous effluent 6 and a liquid effluent 7.

[0268] The gaseous effluent 6 and all of the liquid effluent 7 are mixed and then subjected to a cold separation step c): a water stream 8 is injected into the mixture, the final mixture reaches a temperature of 40°C in a cold HP drum operating at a pressure substantially identical to that of step b), at the outlet of which a hydrogen-rich gas fraction 9, an aqueous fraction 10 and the washed hydrocarbon effluent 11 are obtained. The hydrocarbon effluent 11 is then introduced by means of a pump so as to adjust the total pressure in the hydrotreatment step d) carried out in a fixed bed and in the presence of hydrogen 12 so as to adjust the partial pressure of hydrogen, and a NiMo-on-alumina hydrotreatment catalyst under the conditions presented in Table 4.

[0269] The hydrotreated effluent is then introduced into a low-pressure, low-temperature separator drum to remove dissolved gases. The properties of the hydrotreated effluent, freed from dissolved gases, are presented in Table 4 and comply with the specifications for a feedstock for a steam cracker. All or part of the hydrotreated effluent obtained can then be used in a steam cracking stage to form olefins that can be polymerized to form recycled plastics. Table 4: Operating conditions for stages a), b), c) and d) and properties of the hydrotreated effluent. It is observed that to obtain a hydrotreated effluent meeting the specifications of a feedstock for a steam cracker, the average temperature of hydrotreatment step d) according to example 2 is 10°C lower than that according to example 1. When the catalyst deactivates during its catalytic cycle, the average temperature can be increased in order to compensate for the catalytic deactivation. The temperature increase is possible up to a temperature at which catalyst replacement becomes necessary (end-of-cycle temperature). When a temperature difference between the start of the cycle and the end of the catalytic cycle of 60°C is set, a catalyst deactivation rate and the duration of the catalytic cycle can be deduced.

[0270] Table 5 shows the effect on the cycle time of hydrotreatment step d) with or without separation steps b) and c). It is observed that the cycle time according to Example 1 is 12 months, while the cycle time according to Example 2 is 30 months.

[0271] Table 5: Catalytic cycle time of the hydrotreatment stage with AT (SOR*-EOR**) = 60 °C (*) SOR (start of cycle or start of run according to Anglo-Saxon terminology)

[0272] (*) EOR (end of cycle or end of run according to Anglo-Saxon terminology)

Claims

CLAIMS 1. A method for treating a feedstock comprising a plastic and / or tire pyrolysis oil comprising halogenated compounds, said method comprising: a) a hydrogenation step carried out in a hydrogenation reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrogenation catalyst, said hydrogenation reaction section being fed at least with said feedstock, optionally in a mixture with at least a portion of a liquid effluent from a separation step b), and a first gas stream comprising hydrogen, said hydrogenation reaction section being carried out at an average temperature between 140 and 400°C, a hydrogen partial pressure between 1.0 and 10.0 MPa abs. and an hourly volumetric flow rate between 0.1 and 10.0 h -1, to obtain a hydrogenated effluent, b) a separation step, fed with the effluent from step a), said step being carried out at a temperature higher than the precipitation temperature of the ammonium halides and at a pressure substantially identical to the pressure of step a) to obtain at least a first gaseous effluent and a liquid effluent, part of which is optionally recycled upstream of step a), c) a separation step, fed with the first gaseous effluent and optionally at least part of the liquid effluent from step b), and an aqueous solution, said step being carried out at a temperature lower than the precipitation temperature of the ammonium halides and at a pressure substantially identical or lower than the pressure of step b), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent,d) a hydrotreatment step carried out in a hydrotreatment reaction section, using at least one fixed-bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrotreatment catalyst, said hydrotreatment reaction section being fed at least by said hydrocarbon effluent from step c), optionally by at least a portion of the liquid effluent from step b), and a second gaseous stream comprising hydrogen, said hydrotreatment reaction section being carried out at an average temperature between 250 and 430°C, a partial pressure of hydrogen between 1.0 and 10.0 MPa abs. and an hourly volumetric flow rate between 0.1 and 10.0 h', 1, to obtain a hydrotreated effluent, e) optionally a step of fractionation of all or part of the hydrotreated effluent from step d), to obtain at least a third gaseous effluent, a naphtha cut and at least one middle distillate cut, f) optionally a hydrocracking step implemented in a hydrocracking reaction section, implementing at least one fixed bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of said hydrotreated effluent from step d) and / or with at least a portion of the middle distillates cut from step e) and a third gas stream comprising hydrogen, said hydrocracking reaction section being implemented at an average temperature between 250 and 450°C, a partial pressure of hydrogen between 1.5 and 20.0 MPa abs. and an hourly volumetric velocity between 0.1 and 10.0 h -1 to obtain a first hydrocracked effluent.

2. Method according to the preceding claim, in which step b) is carried out at a temperature between 200 and 450°C and step c) is carried out at a temperature greater than or equal to 20°C and less than 200°C.

3. Method according to one of the preceding claims, in which step c) is supplied with the first gaseous effluent and at least part of the liquid effluent from step b) and an aqueous solution.

4. Method according to one of the preceding claims, in which at least part of the liquid effluent obtained in step b) is recycled upstream of step a).

5. Method according to one of the preceding claims comprising the fractionation step e).

6. Process according to one of the preceding claims comprising the hydrocracking step f).

7. Method according to one of the preceding claims, in which in step a) the hydrogen coverage is between 250 and 800 Nm 3of hydrogen per m 3 load (Nm 3 / m 3 ).

8. Method according to one of the preceding claims, comprising at least one step aO) of pretreatment of the pyrolysis oil fraction of plastics and / or tires, said pretreatment step being carried out upstream of step a) and comprises an adsorption step and / or a filtration step and / or a centrifugation step and / or a decantation step and / or an electrostatic separation step and / or a step of washing using an aqueous solution and / or a gas stripping step.

9. Process according to one of the preceding claims, in which the hydrotreated effluent from hydrotreatment step d), or at least one of the cuts from step e), is sent in whole or in part to a steam cracking step g) carried out in at least one pyrolysis furnace at a temperature between 700 and 900°C and at a pressure between 0.05 and 0.3 MPa relative.

10. Method according to one of the preceding claims in which the reaction section of step a) uses at least two reactors operating in switchable mode.

11. Method according to one of the preceding claims in which a stream containing an amine and / or a sulfur compound is injected upstream of step a).

12. Process according to one of the preceding claims in which said hydrogenation catalyst comprises a support chosen from alumina, silica, silica-aluminas, magnesia, clays and their mixtures and a hydro-dehydrogenating function comprising either at least one element from group VIII and at least one element from group VIB, or at least one element from group VIII.

13. Method according to one of the preceding claims in which said hydrotreatment catalyst comprises a support chosen from the group consisting of alumina, silica, silica-aluminas, magnesia, clays and their mixtures, and a hydro-dehydrogenating function comprising at least one element from group VIII and / or at least one element from group VIB.

14. Process according to one of the preceding claims, which further comprises a second hydrocracking step f') carried out in a hydrocracking reaction section, using at least one fixed bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of the first hydrocracking effluent from the first hydrocracking step f) and a gas stream comprising hydrogen, said hydrocracking reaction section being carried out at a temperature between 250 and 450°C, a partial pressure of hydrogen between 1.5 and 20.0 MPa abs. and an hourly volumetric velocity between 0.1 and 10.0 tr 1 , to obtain a second hydrocracked effluent.

15. Process according to one of the preceding claims, in which said hydrocracking catalyst comprises a support chosen from halogenated aluminas, combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites and a hydro-dehydrogenating function comprising at least one metal from group VI B chosen from chromium, molybdenum and tungsten, alone or in a mixture, and / or at least one metal from group VIII chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

16. Product obtained by the process according to one of claims 1 to 15.

17. Product according to claim 16, which comprises, relative to the total weight of the product: - a total content of metallic elements less than or equal to 10.0 ppm by weight, - with an iron element content of less than or equal to 200 ppb by weight, - a silicon element content less than or equal to 5.0 ppm by weight, - a sulfur content less than or equal to 500 ppm by weight, - a nitrogen content less than or equal to 100 ppm by weight, - a chlorine element content less than or equal to 10 ppm by weight, - a mercury content less than or equal to 5 ppb by weight.

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