Integrated process for treating pyrolysis oil laden with plastic and / or solid recovered fuel impurities - Patents.com

Abstract

The present invention relates to a method for treating plastic pyrolysis oil and / or solid recovered fuel, comprising: a) an optional step of selective hydrogenation of the feedstock; b) hydroconversion in an ebullated, entrained and / or moving bed; obtaining a hydroconverted effluent; c) hydrotreating said hydroconverted effluent obtained from step b); obtaining a hydrotreated effluent; without an intermediate separation step between steps b) and c); c') optionally hydrocracking said effluent from step c), c) separating the effluents from steps c) or c') in the presence of an aqueous stream; obtaining a gaseous effluent, an aqueous liquid effluent and a hydrocarbonaceous liquid effluent; d) optional fractionation; obtaining at least one gaseous stream, a fraction with a boiling point below 175°C and a fraction with a boiling point above 175°C.

Description

[Technical field]

[0001] The present invention relates to an integrated method for treating pyrolysis oils loaded with impurities of plastics and / or solid recovery fuels (SRF), obtaining a hydrocarbon effluent which can be upgraded by at least partial incorporation in naphtha or diesel pools, either directly or as a feedstock for a steam cracking unit. More particularly, the present invention relates to a method for treating a feedstock obtained from the pyrolysis of plastic waste and / or SRF, removing at least a portion of the impurities which said feedstock may contain in large amounts, and hydrogenating the feedstock to allow it to be upgraded. [Background technology]

[0002] The plastics obtained from the collection and sorting channels can undergo a process of pyrolysis to obtain, among other things, pyrolysis oils, which are generally incinerated to generate electricity and / or used as fuel in industrial or municipal heating boilers.

[0003] Solid recovered fuel (SRF), also known as "refuse-derived fuel" or RDF, is solid, non-hazardous waste material, whether generated from household and similar waste, waste from economic activity or construction and demolition waste, that is prepared for energy recovery. SRF is generally a mixture of all combustible waste, such as used tyres, food by-products (fats, animal meals etc.), viscose and wood waste, light debris from shredders (e.g. used vehicles, electrical and electronic equipment (WEEE), household and commercial waste, residues from recycling of different types of waste, including designated municipal waste, plastic waste, textiles and wood etc. SRF generally contains plastic waste. Currently, SRF are mainly recovered for energy. They can be used directly as a replacement for fossil fuels in co-combustion plants (coal and lignite power plants, cement plants, lime kilns) or household waste incineration units, or indirectly in pyrolysis units dedicated to energy recovery: thus, SRF pyrolysis oil is generally combusted to generate electricity or used as fuel in industrial or municipal heating boilers.

[0004] Another route for upgrading the pyrolysis oils of plastics and / or SRF consists in using these pyrolysis oils as feedstock for steam cracking units to (re)produce olefins, which are the constituent monomers of a given polymer. However, plastic waste or SRF is generally a mixture of several polymers, for example a mixture of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride and polystyrene. Furthermore, depending on the application, the plastics may contain, in addition to the polymers, other compounds, for example plasticizers, pigments, dyes or polymerization catalyst residues, as well as a great variety of other organic and inorganic impurities resulting from the separation operations in the sorting centers (the selectivity of which may not be complete). The oils obtained from the pyrolysis of plastics or SRF therefore contain many impurities, in particular diolefins, metals, silicon or halogenated compounds, in particular chlorine-based compounds, heteroelements, for example sulfur, oxygen and nitrogen, as well as insolubles, often in high contents that are incompatible with the steam cracking units or with units located downstream of the steam cracking units, in particular the polymerization and selective hydrogenation processes. These impurities can cause problems of operability, especially corrosion, coking or catalyst deactivation, or also problems of incompatibility in the use of the target polymer. The presence of diolefins very often causes problems of instability of the pyrolysis oil, characterized by the formation of gums. Gums and insoluble materials that may be present in the pyrolysis oil can cause clogging problems in the process.

[0005] Moreover, during the steam cracking process, the yield of light olefins, especially ethylene and propylene, desired for petrochemicals, is highly dependent on the quality of the feedstock sent to the steam cracking. The BMCI (Bureau of Mines Correlation Index) is often used to characterize the hydrocarbon fractions. This index was developed for the hydrocarbon products obtained from crude oil and is calculated from measurements of density and average boiling point: it is equal to 0 for normal paraffins and 100 for benzene. Its value therefore increases proportionately the more naphthenes, condensed aromatic structures with an intermediate BMCI between paraffins and aromatics, that the analyzed product has. Overall, a higher yield of light olefins occurs when the content of paraffins increases, and therefore the BMCI decreases. Conversely, a higher yield of unwanted heavy compounds and / or coke occurs when the BMCI increases.

[0006] In document WO 2005 / 023331 A very general and relatively complex overall process for recycling plastic waste is proposed, which starts right from the step of pyrolysis of plastic waste to a steam cracking step, which comprises, inter alia, a step of hydrotreating the liquid phase obtained directly from the pyrolysis, preferably under very strict conditions, in particular with regard to temperature, for example at a temperature of 260-300°C, a step of separation of the hydrotreating effluent and then a step of hydrodealkylation of the separated heavy effluent, preferably at high temperature, for example at 260-400°C.

[0007] Unpublished patent application FR 20 / 01758 describes a method for treating plastic pyrolysis oil, comprising the steps of: a) selective hydrogenation of said feedstock in the presence of hydrogen and a selective hydrogenation catalyst; obtaining a hydrogenated effluent; b) fixed bed hydrotreating of said hydrogenated effluent in the presence of hydrogen and a hydrotreating catalyst; obtaining a hydrotreated effluent; c) separation step in the presence of an aqueous stream of hydrotreating effluent at a temperature of 50-370°C to obtain a gaseous effluent, an aqueous liquid effluent and a liquid hydrocarbon effluent; d) optionally a step of fractionation of all or part of the hydrocarbon effluent obtained from step c) to obtain a gas stream and at least two hydrocarbon streams, which may be a naphtha fraction and a heavier fraction; e) a recycling step comprising the step of recovering a portion of the hydrocarbon effluent obtained from the separation step c) or a portion of the hydrocarbon stream obtained from the fractionation step d) and / or at least one of said hydrocarbon streams for recycling to the selective hydrogenation step a) and / or to the hydrotreating step b).

[0008] According to patent application FR 20 / 01758, the naphtha fraction obtained from the fractionation step may be sent, in whole or in part, either to a steam cracking unit or to a naphtha pool obtained from conventional petroleum-based feedstocks, or may be recycled to step e).

[0009] The heavier cuts obtained from the fractionation step may be sent, in whole or in part, either to a steam cracking unit or to a diesel or kerosene pool obtained from conventional petroleum-based feedstocks, or may be recycled to step e).

[0010] Unpublished patent applications FR 20 / 08108 and FR 20 / 08106 are based on the process of FR 20 / 01758 and describe a process for treating plastic pyrolysis oil, incorporating one or two steps of hydrocracking in a fixed bed after the hydrotreating step. These processes make it possible to minimize the yield of heavy fractions and maximize the yield of naphtha fractions by converting the latter at least partially by hydrocracking into naphtha fractions, which are generally the fractions preferred for steam cracking units. Heavier fractions can be sent to steam cracking units, but most refiners do not support this option. The reason for this is that heavier fractions have a high BMCI and contain more naphthenic, naphthenoaromatics and aromatic compounds relative to the naphtha fraction, resulting in a higher C / H ratio. This high ratio causes coking in the steam cracker, so a steam cracking furnace dedicated to this fraction is required. Moreover, steam cracking of such heavy fractions produces less of the desired products, particularly ethylene and propylene, while producing more pyrolysis gasoline.

[0011] Due to the content of impurities in pyrolysis oil, deactivation of the catalyst of hydrotreating units operated in fixed beds may be observed, especially when the pyrolysis oil is loaded with a large amount of impurities, which shortens the cycle time.In fact, the main limitation of fixed bed units is the fact that the unit must be shut down to replace the catalyst.Furthermore, pyrolysis oil, especially pyrolysis oil loaded with a large amount of impurities, may cause clogging problems, especially in the preheater, the feed / effluent exchanger or on the top of the bed of the catalytic reactor.

[0012] It would therefore be advantageous to propose a method for processing pyrolysis oil that has a long-lasting catalytic cycle by allowing catalyst replacement without shutting down the unit, while at the same time producing an alkane-rich fraction that can be easily upgraded in a steam cracking unit.

[0013] Hydroconversion units operated with ebullated, entrained or even moving beds are able to process this type of feedstock thanks to systems for adding fresh catalyst and withdrawing spent catalyst without shutting down the unit, which are generally performed continuously, semi-continuously or periodically. These systems compensate for catalyst deactivation due to impurities in the pyrolysis product and solve the problem of plugging of the catalyst bed in reactors operated with fixed beds, allowing the hydroconversion units to have long cycle times without the need for shut downs to replace the catalyst.

[0014] Furthermore, when such a hydroconversion unit is located upstream of a hydroprocessing unit, the cycle time of the hydroprocessing unit is increased by virtue of the hydroprocessing reactions being partially pre-performed in the hydroconversion unit.

[0015] Likewise, the hydrocracking reactions carried out in the hydroconversion unit make it possible to convert at least a portion of the heavy compounds into lighter compounds, which makes it possible, firstly, to feed a fraction which is generally easier to process to the hydrotreating unit, and secondly, to obtain a fraction which has a lower BMCI and is therefore particularly suitable for a steam cracking unit.

[0016] The unpublished patent application FR 20 / 09.750 describes such a method for treating pyrolysis oils of plastics and / or SRF, which method comprises, inter alia, the following steps: a) optionally, a step of selective hydrogenation of said feedstock in the presence of hydrogen and a selective hydrogenation catalyst; obtaining a hydrogenated effluent; b) a hydroconversion step using at least one ebullated bed reactor, entrained bed reactor and / or moving bed reactor, which reactor contains at least one hydroconversion catalyst, said hydroconversion reaction section being fed at least with said feedstock or said hydrogenated effluent obtained from step a) and with a gas stream containing hydrogen, to obtain a hydroconverted effluent; c) a separation step, feeding the hydroconverted effluent from step b) and an aqueous solution, said step being carried out at a temperature between 50 and 450°C; obtaining at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent; d) a step of fractionation of all or part of the hydrocarbon effluent obtained from step c) to obtain at least one gas stream and a hydrocarbon fraction comprising compounds having a boiling point less than or equal to 385° C. and a hydrocarbon fraction comprising compounds having a boiling point greater than 385° C.; e) a hydrotreating step, using at least one fixed bed reactor, which reactor contains at least one hydrotreating catalyst, said hydrotreating reaction section being fed with at least a portion of said hydrocarbon fraction containing compounds having a boiling point less than or equal to 385° C. from step d) and with a gas stream containing hydrogen; obtaining a hydrotreated effluent; f) a separation step; feeding the hydrotreated effluent obtained from step e) to obtain at least a gaseous effluent and a hydrotreated liquid hydrocarbon effluent.

[0017] Research activities have led the Applicant to surprisingly discover that an improvement of the existing process is possible by the combination of various steps linked together in a specific manner. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] International Publication No. 2018 / 055555 Summary of the Invention [Means for solving the problem]

[0019] (Summary of the invention) The present invention relates to a method for processing a feedstock containing pyrolysis oil of plastics and / or solid recycled fuels, the method comprising the steps of: a) an optional step of selective hydrogenation, in which the feedstock and a gas stream containing hydrogen are fed to a reaction section at least in the presence of at least one selective hydrogenation catalyst at a temperature of 100-280° C., a hydrogen partial pressure of 1.0-20.0 MPa (absolute), and an hourly space velocity of 0.3-10.0 h -1 obtaining a hydrogenated effluent; b) a hydroconversion step, carried out in a hydroconversion reaction section using at least one ebullated bed reactor, entrained bed reactor and / or moving bed reactor, which reactor contains at least one hydroconversion catalyst, to which the feedstock or the hydrogenated effluent from step a) and a gas stream containing hydrogen are fed at least, the hydroconversion reaction section being operated at a temperature between 250 and 450° C., the partial pressure of hydrogen being between 1.0 and 20.0 MPa (absolute) and the hourly space velocity being between 0.05 and 10.0 h -1 obtaining a hydroconverted effluent; c) a hydrotreating step, carried out in a hydrotreating reaction section, in at least one fixed bed reactor having n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed with at least a portion of said hydroconverted effluent from step b) and a gas stream comprising hydrogen, said hydrotreating reaction section being carried out at a temperature between 250 and 430° C., with a partial pressure of hydrogen between 1.0 and 20.0 MPa (absolute) and with a volumetric hourly rate between 0.1 and 10.0 h -1 obtaining a hydrotreated effluent; said hydrotreating step c) being carried out after the hydroconversion step b) without an intermediate separation step between the hydroconversion step b) and the hydrotreating step c); c') an optional hydrocracking step, carried out in a hydrocracking reaction section using at least one fixed bed, which comprises n catalyst beds, n being an integer equal to or greater than 1, each of which comprises at least one hydrocracking catalyst, to which at least the hydrotreated effluent from step c) and / or the fraction from step e) comprising compounds having a boiling point above 175°C and a gas stream comprising hydrogen are fed, the average temperature during which the hydrocracking reaction section is between 250 and 450°C, the partial pressure of hydrogen is between 1.5 and 20.0 MPa (absolute) and the hourly space velocity is between 0.1 and 10.0 h -1 obtaining a hydrocracked effluent; sending the hydrocracked effluent to a separation step d); d) a separation step, feeding the hydrotreated effluent from step c) or the hydrocracked effluent from step c') and an aqueous solution, said steps being carried out at a temperature between 50 and 450°C; obtaining at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent; e) optionally fractionating all or part of the hydrocarbon effluent obtained from step d); obtaining at least one gaseous effluent, at least one fraction comprising compounds having a boiling point less than or equal to 175° C. and at least one hydrocarbon fraction comprising compounds having a boiling point greater than 175° C.

[0020] In the following text, the term "pyrolysis oil" means, unless otherwise indicated, oil obtained from the pyrolysis of plastics and / or SRF.

[0021] One advantage of the process according to the invention is that by purifying the pyrolysis oil of at least a portion of its impurities it is possible to hydrogenate it and therefore upgrade it, in particular by incorporating it directly in the fuel pool and / or by adapting it to a process in a steam cracking unit, in order to obtain in particular light olefins which can function as monomers in the manufacture of polymers.

[0022] Another advantage of the present invention is that it prevents the risk of clogging and / or corrosion of the processing units in which the process of the present invention is carried out, which risk is exacerbated by the presence of diolefins, metals and halogenated compounds in pyrolysis oils, often in large quantities.

[0023] The process of the invention thus makes it possible to obtain a hydrocarbon effluent obtained from pyrolysis oil from which the impurities of the starting pyrolysis oil have been at least partially removed, thereby limiting operability problems, such as corrosion, coking or catalyst deactivation problems, which these impurities may cause, in particular in the steam cracking unit and / or in units located downstream of the steam cracking unit, in particular in the polymerization and selective hydrogenation units. The removal of at least a portion of the impurities from the pyrolysis oil also makes it possible to broaden the scope of applications of the target polymer, reducing its incompatibility with the applications.

[0024] By carrying out the hydroconversion step using a system for adding fresh catalyst and withdrawing used catalyst without shutting down the unit upstream of the fixed-bed hydrotreating step, it is particularly possible to process pyrolysis oils carrying large amounts of impurities.

[0025] By carrying out the hydroconversion step with a system for adding fresh catalyst and withdrawing spent catalyst without shutting down the unit upstream of the fixed bed hydrotreating step, not only is it possible to obtain long cycle times for the hydroconversion, but it is also possible to extend the cycle times for the hydrotreating step, and furthermore, the risk of plugging the catalyst bed(s) of the hydrotreating step is reduced.

[0026] By carrying out the hydroconversion step with a system for adding fresh catalyst and withdrawing used catalyst without shutting down the unit upstream of the fixed bed hydrotreating step, it is also possible to convert at least a portion of the heavy compounds into lighter compounds, which makes it possible to obtain an improved yield of a fraction suitable for a steam cracking unit and, if this fraction is sent to steam cracking, to obtain an improved yield of light olefins, while at the same time reducing the risk of significant coke formation and / or corrosion encountered during the subsequent step(s), for example during the step of steam cracking of pyrolysis oil.

[0027] Furthermore, the process according to the invention is characterized in that it does not include an intermediate separation step between the hydroconversion step b) and the hydrotreating step c). Sending the effluent from the hydroconversion step b) directly to the hydrotreating step c) without a separation step has several advantages, among them: - the process has better heat integration since the temperature of the effluent at the outlet of the hydroconversion step b) is maintained, which does not exclude the fact that the temperature of the effluent from the hydroconversion step b) can be controlled and regulated before the hydrotreatment step c); - the process has better energy efficiency since there is no significant pressure drop between the outlet of the hydroconversion section b) and the inlet of the hydrotreatment section c); - the devices making it possible to implement the process, and more particularly the elements necessary for the recycling of hydrogen in this process, can be simplified. In fact, in the absence of intermediate separation, a single hydrogen recirculation loop common to the hydroconversion and hydrotreatment sections is necessary, since there is no exit of a hydrogen-rich gas at the end of the hydroconversion step. A single compressor is therefore sufficient, and the size of this compressor can be reduced if the flow rate of the recycle gas is also lower.

[0028] According to one variant, the process according to the invention comprises a fractionation step e).

[0029] According to one variant, the process according to the invention comprises a hydrocracking step c').

[0030] According to one variant, the process according to the invention comprises said selective hydrogenation step a).

[0031] According to one variant, at least a portion of the hydrocarbon effluent obtained from the separation step d) or at least a portion of the naphtha cut comprising compounds with a boiling point below 175° C. obtained from the fractionation step e) is sent to a selective hydrogenation step a) and / or to a hydrotreating step c).

[0032] According to one variant, at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from the fractionation step e) is sent to a hydroconversion step b) and / or a hydrocracking step c').

[0033] According to one variant, the process according to the invention comprises a step a0) of pretreating the feedstock, said pretreatment step being carried out upstream of the hydrogenation step a) and comprising a filtration step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or an adsorption step.

[0034] According to one variant, the hydrocarbon effluent obtained from the separation step d) or at least one of the two liquid hydrocarbon streams obtained from step e) is sent totally or partly to a steam cracking step f), which is 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).

[0035] According to one variant, the separation step e) also comprises the fractionation of the naphtha fraction containing compounds having a boiling point below 175° C. into a light naphtha fraction containing compounds having a boiling point below 80° C. and a heavy naphtha fraction containing compounds having a boiling point between 80 and 175° C.

[0036] According to one variant, at least a portion of the heavy naphtha fraction is sent to an aromatics complex comprising at least one naphtha reforming step and / or at least a portion of the light naphtha fraction is sent to a steam cracking step f).

[0037] According to one variant, the selective hydrogenation catalyst comprises a support chosen from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group 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.

[0038] According to one variant, when step b) is carried out in an ebullated or moving bed, said hydroconversion catalyst of step b) comprises a supported catalyst comprising a group VIII metal selected from the group formed by Ni, Pd, Pt, Co, Rh and / or Ru, and optionally a group VIB metal selected from the group Mo and / or W, on an amorphous mineral support selected from the group formed by alumina, silica, silica-alumina, magnesia, clay and mixtures of at least two of these minerals; when step b) is carried out in an entrained bed, said hydroconversion catalyst of step b) comprises a dispersed catalyst containing at least one element selected from the group formed by Mo, Fe, Ni, W, Co, V and Ru.

[0039] According to one variant, the hydrotreating catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group comprising at least one element from group VIII and / or at least one element from group VIB.

[0040] According to one variant, the process according to the invention also comprises a second step c''), which is carried out in a hydrocracking reaction section using at least one fixed bed, which comprises n catalyst beds, n being an integer greater than or equal to 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed at least with the fraction comprising compounds having a boiling point above 175°C obtained from step e) and with a gas stream comprising hydrogen, said hydrocracking reaction section being used at a temperature between 250 and 450°C, with a partial pressure of hydrogen between 1.5 and 20.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to the separation step d).

[0041] According to one variant, the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminum, amorphous silica-aluminas and zeolites, and a hydrodehydrogenation functional group comprising at least one metal from group VIB selected, alone or in mixtures, from chromium, molybdenum and tungsten, and / or at least one metal from group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0042] According to one variant, the feedstock has the following characteristics: - the content of aromatic compounds is 0 to 90% by weight; - the content of halogenated compounds is 2 to 5000 ppm by weight; - The content of metal elements is 10 to 10,000 ppm by weight; - containing iron element, the content of which is 0 to 100 ppm by weight; The content of silicon element is 0 to 1000 ppm by weight.

[0043] The present invention also relates to products which may be obtained via the process according to the invention.

[0044] According to one variant, the product comprises, relative to the total weight of the product: - metallic elements with a total content of 5.0 ppm by weight or less, - Contains iron element, the content of which is 100 ppb by weight or less; - elemental silicon with a content not exceeding 1.0 ppm by weight, - sulfur with a content not exceeding 500 ppm by weight, - nitrogen with a content not exceeding 100 ppm by weight, - Elemental chlorine with a content not exceeding 10 ppm by weight.

[0045] According to the invention, pressure is absolute pressure, also expressed as abs. (absolute) and is indicated in MPa (absolute pressure) (or MPa (absolute)), unless otherwise indicated.

[0046] According to the present invention, the expressions "of between ... and ..." and "between ... and ..." are equivalent and mean that both limits of the interval are included within the stated range of values. If this is not the case and if both limits are not included within the stated range, such a clarification is introduced by the present invention.

[0047] For purposes of the present invention, various ranges of parameters for a given process, such as pressure ranges and temperature ranges, may be used alone or in combination, for example, a range of preferred pressure values ​​may be combined with a more preferred range of temperature values ​​within the spirit of the present invention.

[0048] In the following text, specific and / or preferred embodiments of the present invention may be described, which may be implemented separately or in combination together, without any limitation to the combination, provided that the combination is technically feasible.

[0049] The groups of chemical elements are then given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification.

[0050] The metal content is measured by X-ray fluorescence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] (Detailed Description) (Feed material) According to the invention, "plastic pyrolysis oil or SRF pyrolysis oil" is an oil, advantageously in liquid form at ambient temperature, obtained from the pyrolysis of plastics, preferably plastic waste, especially plastic waste originating from collection and sorting channels or from the pyrolysis of SRF. It especially comprises a mixture of hydrocarbon compounds, especially paraffins, olefins, naphthenes and aromatic compounds. A minimum of 80% by weight of these hydrocarbon compounds preferably has a boiling point below 700°C, preferably below 550°C. In particular, depending on the origin of the pyrolysis oil, it can comprise up to 70% by weight of paraffins, up to 90% by weight of olefins and up to 90% by weight of aromatic compounds, the sum of paraffins, olefins and aromatic compounds being understood to be 100% by weight of the hydrocarbon compounds.

[0052] The density of pyrolysis oil is generally between 0.75 and 0.99 g / cm, measured at 15°C according to ASTM D4052 method. 3 , preferably 0.75 to 0.95 g / cm 3 It is.

[0053] Pyrolysis oils may also, and usually do, contain impurities, such as metals, especially iron, silicon, or halogenated compounds, especially chlorinated compounds. These impurities may be present in high concentrations in pyrolysis oils, for example up to 500 ppm by weight, or even up to 1000 ppm by weight, or even up to 5000 ppm by weight of halogen elements provided by halogenated compounds, up to 2500 ppm by weight, or even up to 10000 ppm by weight of metallic or semimetallic elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals and metalloids may be classified in the same category as contaminants of metallic nature, called metals or metallic or semimetallic elements. Pyrolysis oils may contain up to 200 ppm by weight, or even up to 1000 ppm by weight of silicon, and up to 15 ppm by weight, or even up to 100 ppm by weight of iron. The pyrolysis oil may also contain other impurities, such as heteroelements, in particular those provided by sulfur compounds, oxygen compounds and / or nitrogen compounds, generally in a content of less than 20,000 ppm by weight of heteroelements, preferably less than 10,000 ppm by weight of heteroelements.

[0054] The method according to the invention is particularly suitable for treating impure pyrolysis oils, which means a feedstock having the following characteristics: the aromatics content is between 0 and 90% by weight, often between 20 and 90% by weight; it may be between 50% and 90% by weight; the halogen content is between 2 and 5000 ppm by weight, often between 200 and 5000 ppm by weight, it may be between 500 and 5000 ppm by weight; the content of metallic elements is between 10 and 10 000 ppm by weight, often between 2 000 and 10 000 ppm by weight, it may be between 2 250 and 5 000 ppm by weight; - containing elemental iron, the content of which is between 0 and 100 ppm by weight, often between 10 and 100 ppm by weight, it may be between 15 and 100 ppm by weight; The silicon element content is between 0 and 1000 ppm by weight, often between 100 and 1000 ppm by weight, it may be between 200 and 1000 ppm by weight.

[0055] The process according to the invention is particularly suitable for treating pyrolysis oils carrying large amounts of impurities, which means a feedstock having the following characteristics: - the content of aromatic compounds is between 30% and 70% by weight; - the content of halogenated compounds is from 500 to 5000 ppm by weight; - the content of metallic elements is 300-10,000 ppm by weight; - contains iron element, the content of which is 15-100 ppm by weight; The silicon content is 200 to 1000 ppm by weight.

[0056] The feedstock for the process according to the invention comprises at least one plastic and / or SRF pyrolysis oil. The feedstock may consist exclusively of plastic pyrolysis oil(s) or exclusively of SRF pyrolysis oil(s) or exclusively of a mixture of plastic and SRF pyrolysis oil(s). Preferably, the feedstock comprises at least 50% by weight, preferably 50% to 100% by weight, particularly preferably 75% to 100% by weight, of plastic and / or SRF pyrolysis oil.

[0057] The pyrolysis oil of plastics and / or SRF may be obtained from a thermal catalytic pyrolysis process or alternatively may be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0058] The feedstock for the process according to the invention may also comprise a conventional petroleum-based feedstock and / or a feedstock obtained from the conversion of biomass, which is then co-processed with plastics and / or SRF pyrolysis oil.

[0059] The conventional petroleum-based feedstock may advantageously be a fraction or a mixture of fractions of the following types: naphtha, vacuum gas oil, atmospheric resid or vacuum resid.

[0060] The feedstock obtained from the conversion of biomass may advantageously be selected from vegetable oils, algae-derived oils or algae oils, fish oils, waste cooking oils, and fats of vegetable or animal origin, or a mixture of such feedstocks. The vegetable oils may advantageously be crude oils or fully or partially refined oils, and may originate from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor oil plants, cotton plants, peanut oil, linseed oil and cranberry oil, and all oils obtained, for example, from sunflower or rapeseed by genetic modification or breeding, without being limited to this list. The animal fats are advantageously selected from fats composed of blubber and residues from the food industry or from the catering industry. Frying oils, various animal oils, such as fish oil, tallow, or lard, may also be used.

[0061] The feedstock obtained from the conversion of biomass can also be selected from biomass and / or organic waste, for example feedstocks derived from various liquefaction processes, for example thermal or catalytic conversion of oils produced by hydrothermal liquefaction or pyrolysis, from biomass, especially lignocellulosic biomass. The term "biomass" refers to materials derived from recently living organisms, including 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 aromatic polymers (lignin).

[0062] The feedstock obtained from the conversion of biomass may advantageously also be chosen from feedstocks obtained from the paper industry.

[0063] (Preprocessing (optional)) Said feedstock comprising pyrolysis oil may advantageously be pretreated in an optional pretreatment step a0) before the optional selective hydrogenation step a) or, if step a) is not present, before the hydroconversion step b), to obtain a pretreated feedstock, which is fed to step a) or to step b).

[0064] This optional pretreatment step a0) makes it possible to reduce the amount of contaminants, in particular the amount of silicon and metals, that may be present in the feedstock comprising pyrolysis oil.For this reason, the optional step a0) of pretreatment of the feedstock comprising pyrolysis oil may in particular be carried out when said feedstock comprises more than 50 ppm by weight, in particular more than 100 ppm by weight and more particularly more than 200 ppm by weight of metallic elements.

[0065] Said optional pretreatment step a0) may be carried out by any method known to the person skilled in the art making it possible to reduce the amount of contaminants. It may in particular comprise a filtration step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or an adsorption step.

[0066] The optional pretreatment step a0) is advantageously carried out at a temperature of 0 to 150° C., preferably 5 to 100° C., and at a pressure of 0.15 to 10.0 MPa (absolute), preferably 0.2 to 1.0 MPa (absolute).

[0067] According to one variant, the optional pretreatment step a0) is carried out in an adsorption section operated in the presence of at least one adsorbent, preferably of the alumina type, which has a specific surface area of ​​at least 100 m 2 / g or more, preferably 200m 2 The specific surface area of ​​said at least one adsorbent is advantageously 600 m 2 / g or less, especially 400m 2The specific surface area of ​​the adsorbent is the surface area measured by the BET method, i.e. the specific surface area determined by nitrogen adsorption according to standard ASTM D 3663-78, which is derived from the Brunauer-Emmett-Teller method described in the journal The Journal of the American Chemical Society, 6Q, 309 (1938).

[0068] Advantageously, said adsorbent contains less than 1% by weight of metal elements, preferably no metal elements. Metal elements of the adsorbent should be understood to mean elements of groups 6 to 10 of the Periodic Table of Elements (new IUPAC classification). The residence time of the feedstock in the adsorbent section is generally between 1 and 180 minutes.

[0069] The adsorption section of optional step a0) comprises at least one adsorption tower, preferably at least two adsorption towers, preferentially 2 to 4 adsorption towers, which contain the adsorbent. If the adsorption section comprises two adsorption towers, one operation mode can be a "swing" operation, where one of the towers is on-line, i.e. in operation, while the other tower is in reserve. When the adsorbent of the on-line tower is exhausted, this tower is isolated, while the in-reserve tower is placed on-line, i.e. in operation. The used adsorbent is subsequently regenerated in situ and / or replaced with fresh adsorbent, so that the tower containing it can again be placed on-line where the other tower is isolated.

[0070] Another mode of operation is to have at least two towers operated in series. When the adsorbent of the first tower is exhausted, this first tower is isolated and the spent adsorbent is either regenerated in situ or replaced with fresh adsorbent. The tower is then brought back online in the last position, and so on. This operation is known as permutable mode, or PRS for Permutable Reactor System, or by other terms "lead and lag". The combination of at least two adsorption towers makes it possible to overcome possible and potentially rapid poisoning and / or clogging of the adsorbent due to the combined action of metallic contaminants, diolefins, gums derived from diolefins, and insolubles that may be present in the pyrolysis oil to be treated. The reason for this is that the presence of at least two adsorption columns allows easy replacement and / or regeneration of the adsorbent, advantageously without shutting down the pretreatment unit or even the process, thus reducing the risk of clogging and thus making it possible to avoid shutting down the unit due to clogging, control costs and limit adsorbent consumption.

[0071] According to another variant, said optional pretreatment step a0) is carried out in a section for washing with an aqueous solution, for example water or an acidic or basic solution. This washing section can include equipment making it possible to contact the feedstock with the aqueous solution and separate the phases in order to obtain, on the one hand, a pretreated feedstock and, on the other hand, an aqueous solution containing impurities. These equipment can include, for example, stirred reactors, decanters, mixer-decanters and / or cocurrent or countercurrent scrub washing columns.

[0072] Said optional pretreatment step a0) may optionally be fed at least a portion of a recycle stream, advantageously obtained from step d) or from optional step e) of the process, either in a mixture with the feedstock comprising pyrolysis oil or separately thereto.

[0073] Said optional pretreatment step a0) thus makes it possible to obtain a pretreated feedstock which is then fed to the selective hydrogenation step a), if present, or to the hydroconversion step b).

[0074] (Selective hydrogenation step a) (optional) According to the invention, the process may comprise a step a) of selective hydrogenation of a feedstock comprising pyrolysis oil, which step a) is carried out in the presence of hydrogen, under conditions of hydrogen pressure and temperature making it possible to maintain said feedstock in the liquid phase, and with an amount of soluble hydrogen just required for the selective hydrogenation of the diolefins present in the pyrolysis oil. The selective hydrogenation of diolefins in the liquid phase thus makes it possible to avoid or at least limit the formation of "gums", i.e. the polymerization of diolefins and thus the formation of oligomers and polymers, which may clog the reaction section of the hydrotreating step c). Styrenic compounds, especially styrene, which may be present in the feedstock, may also behave similarly to diolefins with respect to the formation of gums, due to the fact that the double bond of the vinyl group is conjugated with the aromatic nucleus. The selective hydrogenation step a) makes it possible to obtain a selectively hydrogenated effluent, i.e. an effluent with a reduced content of olefins, especially diolefins, and possibly styrene compounds.

[0075] According to the invention, the selective hydrogenation step a) is carried out by reacting the feedstock containing pyrolysis oil or the pretreated feedstock obtained from the optional pretreatment step a0) with hydrogen (H 2 ) is fed to a reaction section at least containing a gas stream.

[0076] Optionally, the reaction section of said step a) may likewise be fed with a recycle stream, advantageously at least a portion of a recycle stream obtained from step d) or from optional step e).

[0077] The reaction section is preferably carried out in the presence of at least one selective hydrogenation catalyst, preferably in a fixed bed, at an average temperature (or WABT as defined below) advantageously between 100 and 280°C, preferably between 120 and 260°C, preferably between 130 and 250°C, at a partial pressure of hydrogen between 1.0 and 20.0 MPa (absolute), preferably between 5.0 and 15.0 MPa (absolute) and at a rate of 0.3 to 10.0 h -1 , preferably 0.5 to 5.0 h -1 This includes selective hydrogenation at an hourly space velocity (HSV) of 1000 MPa.

[0078] According to the invention, the "average temperature" of a reaction section containing at least one fixed bed reactor corresponds to the weight-average bed temperature (WABT), which is well known to those skilled in the art. The average temperature is advantageously determined depending on the catalyst system used, the equipment and their configuration. The average temperature (i.e. WABT) is calculated as follows:

[0079]

number

[0080] In the formula, T inlet : temperature of the effluent at the inlet of the reaction section, T outlet is the temperature of the effluent at the outlet of the reaction section.

[0081] Hourly space velocity (HSV) is defined herein as the ratio of the hourly volumetric flow rate of the pyrolysis oil-containing feedstock, optionally pretreated, to the volume of the catalyst(s).

[0082] Hydrogen (H 2 ) is advantageously determined by the hydrogen coverage of the feedstock volume (m 3 ) Hydrogen 1-200Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3) Hydrogen 1~50Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 5~20Sm 3 (Sm 3 / m 3 ) is the amount.

[0083] The hydrogen coverage is defined as the ratio of the volumetric flow rate of hydrogen measured under standard conditions of temperature and pressure (per volume of feed (m )) relative to the volumetric flow rate of the “fresh” feed at 15° C., i.e. the feed to be treated, possibly pretreated (not taking into account possible recycle fractions). 3 ) H per 2 Standard m 3 (Sm 3 is shown).

[0084] The hydrogen-containing gas stream feeding the reaction section of step a) may consist of a hydrogen feed and / or recycled hydrogen advantageously obtained from step d) or optional step e).

[0085] The selective hydrogenation step a) is preferably carried out in a fixed bed. It can also be carried out in an ebullated or moving bed.

[0086] Advantageously, the reaction section of step a) comprises from 1 to 5 reactors. According to a particular embodiment of the invention, the reaction section comprises from 2 to 5 reactors, which are operated in a sequence-variable mode, referred to as PRS for Permutable Reactor System or alternatively as "lead and lag". The combination of at least two reactors in PRS mode makes it possible to isolate a reactor, drain the spent catalyst, recharge the reactor with fresh catalyst and put said reactor back into operation without stopping the process. The PRS technology is particularly described in patent FR 2 681 871.

[0087] According to a particularly preferred variant, the selective hydrogenation reaction section of step a) comprises two reactors operated in variable sequence mode.

[0088] Advantageously, reactor internals, for example of the filter plate type, can be used to prevent clogging of the reactor(s). Examples of filter plates are described in patent FR 3 051 375.

[0089] Advantageously, said selective hydrogenation catalyst comprises a support, preferably a mineral support, and a hydrodehydrogenation functional group.

[0090] According to one variant, the hydrodehydrogenation functional group comprises in particular at least one element from group VIII and at least one element from group VIB, the at least one element from group VIII being preferably chosen from nickel and cobalt and the at least one element from group VIB being preferably chosen from molybdenum and tungsten. According to this variant, the total content of metal elements from groups VIB and VIII, expressed as oxide, is preferably between 1% and 40% by weight, preferentially between 5% and 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 MoO, respectively. 3 and W.O. 3 It is expressed as:

[0091] The weight ratio, expressed as metal oxide, of the metal(s) from group VIB relative to the metal(s) from group VIII is preferably from 1 to 20, suitably from 2 to 10.

[0092] According to this variant, the reaction section of step a) for example comprises a hydrogenation catalyst containing between 0.5% and 12% by weight of nickel, preferably between 1% and 10% by weight of nickel (expressed as nickel oxide NiO relative to the weight of the catalyst) and between 1% and 30% by weight of molybdenum, preferably between 3% and 20% by weight of molybdenum (expressed as molybdenum oxide MoO relative to the weight of the catalyst). 3 (represented as:) on a preferably inorganic support, preferably an alumina support.

[0093] According to another variant, the hydrodehydrogenation functional group comprises, and preferably consists of, at least one element from group VIII, preferably nickel. According to this variant, the nickel content, expressed as NiO, 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 used in its reduced form, preferably on an inorganic support, preferably on an alumina support.

[0094] The support of said at least one selective hydrogenation catalyst is preferably selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may contain a dopant compound, in particular an oxide selected from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and mixtures of these oxides. Preferably, said at least one selective hydrogenation catalyst comprises an alumina support, optionally doped with phosphorus and optionally with boron. Phosphorus pentoxide P 2 O 5 If present, its concentration is less than 10% by weight relative to the weight of the alumina, and advantageously is at least 0.001% by weight relative to the total weight of the alumina. 2 O 3 If 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. The alumina used can be, for example, γ (gamma) or η (eta) alumina.

[0095] The selective hydrogenation catalyst is, for example, in the form of extrudates.

[0096] Highly preferably, in order to hydrogenate diolefins as selectively as possible, step a) comprises, in addition to the selective hydrogenation catalyst described above, 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 the catalyst, and molybdenum oxide MoO relative to the weight of the catalyst. 3 At least one selective hydrogenation catalyst used in step a) may be used which contains less than 5 wt.-% molybdenum, expressed as molybdenum per mol of 100% by weight, and a minimum of 0.1 wt.-% molybdenum, preferably 0.5 wt.-% molybdenum, on an alumina support. This catalyst with a modest metal loading is preferably placed upstream of the selective hydrogenation catalyst described above.

[0097] The hydrogenated effluent obtained at the end of step a) has a reduced content of impurities, especially diolefins, relative to the content of the same impurities, especially diolefins, contained in the feedstock of the process.The selective hydrogenation step a) generally allows for a conversion of at least 90%, preferably at least 99%, of the diolefins contained in the initial feedstock.The step a) also allows for at least partial removal of other contaminants, such as silicon.The hydrogenated effluent obtained at the end of the selective hydrogenation step a) is preferably sent directly to the hydroconversion step b).

[0098] (Hydroconversion step b) According to the invention, the process comprises a hydroconversion step b), which is carried out in a hydroconversion reaction section comprising at least one ebullated bed reactor, entrained bed reactor and / or moving bed reactor, which reactor comprises at least one hydroconversion catalyst, said hydroconversion reaction section being fed at least with said feedstock or said hydrogenated effluent obtained from step a) to obtain a hydroconverted effluent.

[0099] Advantageously, step b) comprises hydroconversion reactions well known to those skilled in the art, more particularly hydrotreating reactions, such as hydrogenation of olefins, aromatics, halogenated compounds, hydrodemetallization, hydrodesulfurization, hydrodenitrification, as well as hydrocracking reactions (HCK) which lead to the opening of naphthenic rings or the fractionation of paraffins into several fragments of lower molecular weight, thermal cracking and, undesirably, polycondensation reactions (formation of coke).

[0100] Advantageously, the hydroconversion reaction section is operated at a pressure equivalent to that used in the reaction section of selective hydrogenation step a), if present, but at a temperature higher than that of the reaction section of selective hydrogenation step a). Thus, irrespective of whether ebullated, entrained and / or moving bed reaction sections are used, the hydroconversion reaction section is advantageously operated at a temperature between 250 and 450° C., preferably between 350 and 420° C., with a hydrogen partial pressure between 1.0 and 20.0 MPa (absolute), more preferentially between 3.0 and 15.0 MPa (absolute), with an hourly space velocity (HSV) between 0.05 and 10.0 h -1 , preferably 0.1 to 5.0 h -1 It is.

[0101] According to the invention, the "hydroconversion temperature" corresponds to the average temperature in the hydroconversion reaction section of step b). The hydroconversion temperature is advantageously determined by the skilled person depending on the catalyst system, the equipment and their configuration. For example, the ebullated bed hydroconversion temperature is determined by taking the arithmetic mean of the temperature measurements in the catalyst bed. The hourly space velocity (HSV) is defined here as the ratio of the hourly volumetric flow rate by the volume of hydrogenated effluent obtained from step a) per volume of catalyst(s). The hydrogen coverage in step b) is advantageously determined by the volume of fresh feedstock (m 3 ) Hydrogen 50~1000Sm 3 , preferably the volume of fresh feedstock (m 3 ) Hydrogen 60~500Sm 3, preferably the volume of fresh feedstock (m 3 ) Hydrogen 100~300Sm 3 The hydrogen coverage is defined as the ratio of the volumetric flow rate of hydrogen measured under standard conditions of temperature and pressure to the volumetric flow rate of the "fresh" feed, i.e. the feed to be treated, possibly pretreated, not taking into account possible recycle fractions, at 15°C (volume (m ) of the feed). 3 ) H per 2 Standard m 3 (Sm 3 The hydrogen-containing gas stream fed to the reaction section of step b) may consist of a hydrogen feed and / or recycled hydrogen advantageously obtained from step d) or optional step e).

[0102] An important feature of the process according to the invention is the fact that the hydroconversion step is carried out in a reaction section which allows the addition of fresh catalyst and the withdrawal of spent catalyst without shutting down the unit. Such systems are hydroconversion units operated in ebullated bed, entrained bed and / or even moving bed. The addition of fresh catalyst and the withdrawal of spent catalyst can thus be carried out continuously, semi-continuously or periodically.

[0103] (Ebullated bed hydroconversion process b) Therefore, according to a first variant, the hydroconversion step b) is carried out in a hydroconversion reaction section comprising at least one ebullated bed reactor.

[0104] The functioning of ebullated bed reactors is generally known, including recycling the reactor liquid upwards through a stirred bed of catalyst. A mixture of feedstock and hydrogen passes from bottom up over a bed of catalyst particles at a flow rate such that the particles are forced to undergo random motion while liquid and gas pass from bottom up through the bed. The movement of the catalyst bed is controlled by the flow of recycled liquid so that, in steady state, the mass of catalyst does not rise above a predeterminable level in the reactor. The vapors and liquids to be hydrogenated pass through the upper level of the bed of catalyst particles and reach a zone substantially free of catalyst before they are discharged from the top of the reactor. A portion of the reactor liquid is continuously recycled to the reactor. The ebullated bed technology uses supported catalysts, generally in the form of extrudates or beads, the diameter of which is generally around or less than 1 mm. The catalyst remains inside the reactor and is not discharged with the product. The catalyst activity can be kept constant by online replacement of the catalyst. It is therefore not necessary to shut down the unit to replace the spent catalyst or to increase the reaction temperature along the cycle to compensate for deactivation. Furthermore, working under constant operating conditions makes it possible to obtain constant product yields and qualities along the cycle. Also, because the catalyst is kept stirred by a large liquid recycle, the pressure drop in the reactor remains low and constant, and the reaction heat release is rapidly averaged over the catalyst bed.

[0105] The spent catalyst is partially exchanged for fresh catalyst by withdrawing it from the bottom of the reactor and introducing fresh or new catalyst at regular time intervals, i.e., for example, in bursts or almost continuously, either at the top of the reactor or at the bottom of the reactor. Fresh catalyst can be introduced, for example, daily. The exchange rate of spent catalyst with fresh catalyst can be, for example, from about 0.01 to about 10 kilograms per cubic meter of feedstock volume. This withdrawal and this exchange are carried out with devices that allow the continuous functioning of this hydroconversion step. This unit is usually equipped with an internal recycle pump to keep the catalyst in a boiling bed, which is done by continuously recycling at least a portion of the liquid withdrawn at the top of the reactor and reinjected at the bottom of the reactor. It is also possible to send the spent catalyst withdrawn from the reactor to a regeneration zone, where the carbon and sulfur it contains are removed and then this regenerated catalyst is returned to the hydroconversion step. The regenerated catalyst may be sent to a rejuvenation zone where treatments aimed at improving the activity of the catalyst (presulfiding, additivation, etc.) are carried out, and then the reactivated catalyst is returned to the hydroconversion process.

[0106] The catalysts used in ebullated beds are widely available commercially. They are granular catalysts whose size never reaches that of the catalysts used in entrained beds. The catalysts are usually in the form of extrudates or beads. Typically, they contain at least one hydrodehydrogenation element deposited on an amorphous support. In general, supported catalysts contain a group VIII metal selected from the group formed by Ni, Pd, Pt, Co, Rh and / or Ru, and optionally a group VIB metal selected from the group formed by Mo and / or W, on an amorphous mineral support selected from the group formed by alumina, silica, silica-alumina, magnesia, clay and mixtures of at least two of these minerals. CoMo / alumina and NiMo / alumina catalysts are the most common.

[0107] The total content of oxides of metallic elements from groups VIB and VIII is preferably between 0.1% and 40% by weight, preferentially between 5% and 35% by weight, relative to the total weight of the catalyst. The weight ratio, expressed as metal oxide, of the metal (or metals) from group VIB relative to the metal (or metals) from group VIII is preferably between 1.0 and 20, suitably between 2.0 and 10. For example, the hydroconversion reaction section of step b) of the method may contain 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 hydroconversion catalyst, and between 1.0% and 30% by weight of molybdenum, preferably between 3.0% and 29% by weight of molybdenum (molybdenum oxide MoO 3 and on a mineral support, preferably an alumina support.

[0108] The support for the hydroconversion catalyst is advantageously selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may further comprise a dopant compound, in particular an oxide selected from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and mixtures of these oxides. Preferably, the hydroconversion catalyst comprises an alumina support, preferably an alumina support doped with phosphorus and optionally boron. Phosphorus pentoxide P 2 O 5 If present, its concentration is less than 10% by weight relative to the weight of the alumina, and advantageously is at least 0.001% by weight relative to the total weight of the alumina. 2 O 3 If present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously is at least 0.001% by weight relative to the total weight of the alumina. The alumina used can be, for example, γ (gamma) or η (eta) alumina.

[0109] The hydroconversion catalyst may be in the form of, for example, extrudates or beads.

[0110] Advantageously, the hydroconversion catalyst used in step b) of the process has a specific surface area of ​​250 m 2 / g or more, preferably 300m 2 The specific surface area of ​​the hydroconversion catalyst is advantageously 800 m 2 / g or less, preferably 600m 2 / g or less, especially 400m 2 / g or less. The specific surface area of ​​the hydroconversion catalyst is measured by the BET method, i.e., the specific surface area is determined by nitrogen adsorption according to the standard ASTM D 3663, which is derived from the Brunauer-Emmett-Teller method described in the journal The Journal of the American Chemical Society, 6Q, 309 (1938). Such a specific surface area allows for a further improvement in the removal of contaminants, in particular metals, such as silicon.

[0111] Hydroconversion catalysts are distinguished from hydrotreating catalysts notably by a porosity adapted to the treatment of impurities, especially metallic impurities, and in particular by the presence of macroporosity.

[0112] According to another aspect of the invention, the hydroconversion catalyst also comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to by the term "additivated catalyst". In general, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide groups, or also compounds containing a furan ring or sugars.

[0113] (Entrained bed hydroconversion process b) According to a second variant, the hydroconversion step b) is carried out in a hydroconversion reaction section comprising at least one entrained bed reactor. An entrained bed reactor is also called a slurry reactor. The feedstock, hydrogen and catalyst are injected from below and flow upwards. The hydroconverted effluent and unconsumed hydrogen and catalyst are withdrawn at the top. In the slurry hydroconversion technique, a catalyst is used that is dispersed in the form of very small particles, the size of which is less than a few tens of microns (typically between 0.001 and 100 μm). The catalyst, or its precursor, is injected at the inlet of the reactor together with the feedstock to be converted. The catalyst passes through the reactor together with the feedstock and the products undergoing conversion and leaves the reactor together with the reaction products. They are found in the heaviest fraction after separation.

[0114] The slurry catalysts are catalysts which preferably contain at least one element selected from the group formed by Mo, Fe, Ni, W, Co, V and Ru. These catalysts are generally monometallic or bimetallic catalysts (for example by combining non-noble metal group VIIIB elements (Co, Ni, Fe) with group VIB elements (Mo, W)).

[0115] The catalysts used may be heterogeneous solid powders (e.g. (natural ores, iron sulfate, etc.), dispersed catalysts obtained from water-soluble precursors ("water-soluble dispersed catalysts"), such as phosphomolybdic acid, ammonium molybdate, or mixtures of Mo or Ni oxides with aqueous ammonia.

[0116] Preferably, the catalyst used is derived from a precursor that is soluble in the organic phase ("oil-soluble dispersed catalyst"). The precursor is an organometallic compound, such as naphthenates of Mo, Co, Fe, or Ni, or a multicarbonyl compound of these metals, such as 2-ethylhexanoate of Mo or Ni, acetylacetonate of Mo or Ni, C of Mo or W, etc. 7 ~C 12Salts of fatty acids, etc. They can be used in the presence of surfactants to improve dispersion of the metals when the catalyst is bimetallic.

[0117] The catalyst is in the form of dispersed particles, which may be colloidal or non-colloidal depending on the nature of the catalyst. Such precursors and catalysts which may be used in the process according to the invention are widely described in the literature.

[0118] The catalyst concentration, expressed as elemental metal, is generally between 1 and 10,000 ppm relative to the feed.

[0119] Generally, the catalyst is prepared before being injected into the feedstock. The preparation method is adapted depending on the state and nature of the precursor. In all cases, the precursor is sulfided (ex-situ or in-situ) to form the catalyst dispersed in the feedstock.

[0120] In the preferred case of an "oil-soluble" catalyst in a typical process, the precursor is mixed with a carbon-based feedstock (which may be a part of the feedstock to be treated, an external feedstock, a recycle fraction, etc.), and this mixture is optionally at least partially dried, followed or simultaneously by addition of a sulfur compound (H 2 The catalyst is sulfurized by adding 0.1 to 1.5 S (preferably S) and heated. The preparation of these catalysts is described in the prior art.

[0121] The additives may be added during the preparation of the catalyst or to the slurried catalyst before it is injected into the reactor. These additives are described in the literature.

[0122] Suitable solid additives are mineral oxides, such as alumina, silica, Al / Si mixed oxides, spent supported catalysts (for example on alumina and / or on silica) containing at least one group VIII element (for example Ni, Co) and / or at least one element of group VIB (for example Mo, W). Mention will be made, for example, of the catalysts described in patent application US 2008 / 177124. Carbon-based solids with a low hydrogen content (for example 4% hydrogen), such as coke, possibly pretreated coke, may also be used. Mixtures of such additives may also be used. Their particle size is preferably less than 1 mm. The content of any solid additive present at the inlet of the entrained bed hydroconversion reaction zone is between 0 and 10% by weight, preferentially between 1% and 3% by weight, relative to the weight of the injected feedstock, and the content of the catalyst solution is between 0 and 10% by weight, preferably between 0 and 1% by weight.

[0123] If the hydroconversion step b) is carried out in an entrained bed reactor, a filtration step to recover the catalyst is necessary before passing the hydroconverted effluent to step c).

[0124] (Moving bed hydroconversion process b)) According to a third variant, the hydroconversion step b) is carried out in a hydroconversion reaction section comprising at least one moving bed reactor.

[0125] The feedstock and hydrogen can flow upwards (countercurrent method) or downwards (cocurrent method) in the moving bed reactor. The catalyst flows gradually from top to bottom by gravity and flows in plug flow through the catalytic zone. It is withdrawn from below by any suitable means, for example an elevator (called a "lift"). An in-line device ensures semi-continuous renewal of the catalyst in the moving bed reactor: a part of the used catalyst is removed at the bottom of the reactor, while fresh catalyst is introduced at the top of the reactor. The temperature is controlled there by quench cooling between or within the reactors.

[0126] Preferably, spherical catalysts with a diameter of 0.5-6 mm, preferably 1-3 mm, are used rather than extruded catalysts to obtain better flow. When the spent catalyst is withdrawn from the bottom of the reactor, the entire catalyst bed moving in plug flow moves downwards by a height corresponding to the volume of the withdrawn catalyst. The swelling degree of the catalyst bed operated as a moving bed is advantageously less than 15%, preferably less than 10%, preferably less than 5%, more preferably less than 2%. The swelling degree is measured according to methods known to those skilled in the art.

[0127] The hydroconversion catalyst used in the moving bed of step b) of the process according to the invention is advantageously a catalyst comprising a support, preferably an amorphous support, highly preferably alumina, and at least one group VIII metal selected from nickel and cobalt, preferably nickel, said group VIII element being preferably used in combination with at least one group VIB metal selected from molybdenum and tungsten, preferably the group VIB metal being molybdenum. Preferably, the hydroconversion catalyst comprises nickel as group VIII element and molybdenum as group VIB element. The nickel content is advantageously between 0.5% and 10% by weight, preferably between 1% and 6% by weight, expressed in terms of the weight of nickel oxide (NiO), and the molybdenum content is preferably between 0.5% and 10% by weight, preferably between 1% and 6% by weight, expressed in terms of the weight of molybdenum trioxide (MoO 3 ) and advantageously between 1% and 30% by weight, preferably between 4% and 20% by weight, the percentages being expressed as percentages by weight relative to the total weight of the catalyst. The catalyst is advantageously in the form of extrudates or beads. The catalyst may advantageously contain phosphorus, preferably phosphorus pentoxide P 2 O 5 is less than 20% by weight, preferably less than 10% by weight, the percentages being expressed as percentages by weight relative to the total weight of the catalyst. This catalyst may be a catalyst supplemented with the above organic compounds.

[0128] According to yet another variant, the hydroconversion step b) may be carried out in a hydroconversion reaction section comprising a combination, in any order, of at least one ebullated bed reactor, at least one entrained bed reactor and / or at least one moving bed reactor.

[0129] Preferably, step b) is carried out in a hydroconversion reaction section comprising at least one ebullated bed reactor.

[0130] (Hydrotreatment step c)) According to the invention, the process comprises a hydrotreating step c), which is carried out in a hydrotreating reaction section and which is carried out in at least one fixed bed reactor having n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed with at least a portion of said hydroconverted effluent from step b) and with a gas stream comprising hydrogen to obtain a hydrotreated effluent, said hydrotreating step c) being carried out after hydroconversion step b) and without an intermediate separation step between hydroconversion step b) and hydrotreating step c).

[0131] According to the invention, the effluent from the hydroconversion step b) does not undergo any step of intermediate separation of the gas stream between the hydroconversion step b) and the hydrotreatment step c), this configuration can be described as an integrated scheme.

[0132] In the present invention, the expression "without any intermediate separation step" is understood to mean the fact that at least a part of the effluent from the hydroconversion step b) is introduced into a section that allows the implementation of the hydrotreatment step c) without changing its chemical composition and without significant pressure losses. The term "separation" is understood to mean one or more separation drums and / or one or more stripping or distillation columns, these pieces of equipment being capable of operating at different temperatures or pressures. The expression "significant pressure losses" is understood to mean pressure losses caused by expansion turbines or expansion valves, which may be estimated at more than 10% of the total pressure. Those skilled in the art generally use these pressure losses or expansions during the separation steps.

[0133] In one embodiment of the process according to the invention, the entire effluent from the hydroconversion step b) is introduced into a section making it possible to carry out a hydrotreatment step c).

[0134] In another embodiment, only a part of the effluent from the hydroconversion step b) is introduced into the section allowing the implementation of a hydrotreating step c). However, this embodiment does not contradict the fact that the method does not include any intermediate separation steps. This embodiment may consist in splitting the effluent from the hydroconversion step b) into two streams having the same composition and directing one of the streams to a hydrotreating step c) located downstream of said hydroconversion step. This embodiment can therefore be likened to a partial bypass of the hydrotreating section c), but without separation, modification of chemical composition or significant pressure loss in the part of the effluent of the hydroconversion section b) directed to the hydrotreating section c). Another variant of this bypass embodiment may consist in splitting the effluent from the hydroconversion step b) into several streams having the same composition and sending one or more of these streams to the inlet of the first hydrotreating reactor c) and one or more other of these streams downstream of the downstream hydrotreating reactor(s) c).

[0135] Advantageously, step c) employs hydrotreating reactions well known to those skilled in the art, more particularly hydrotreating reactions such as hydrogenation, hydrodesulfurization and hydrodenitrification of aromatic compounds, furthermore hydrodemetallization is continued with hydrogenation of the remaining halogenated compounds and olefins.

[0136] The average hydrotreating temperature when the hydrotreating reaction section is advantageously operated is 250 to 430°C, preferably 300 to 400°C, the hydrogen partial pressure is 1.0 to 20.0 MPa (absolute), preferably 3.0 to 15.0 MPa (absolute), and the hourly space velocity (HSV) is 0.1 to 10.0 h -1 , preferably 0.1 to 5.0 h -1 , preferentially 0.2~2.0h -1 , preferably 0.2 to 1.0 h -1 The hydrogen coverage in step c) is advantageously determined by the volume (m ) of the feedstock fed to step c). 3 ) Hydrogen 50~2000Nm 3 , preferably the volume (m 3 ) Hydrogen 100-1000Nm 3 , preferably the volume (m 3 ) Hydrogen 120~800Nm 3 It is.

[0137] The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those given above for the selective hydrogenation step a).

[0138] The hydrogen-containing gas stream feeding the reaction section of step c) may consist of a hydrogen feed and / or recycled hydrogen advantageously obtained from step d) or optional step e).

[0139] Advantageously, said step c) is carried out in a hydrotreatment reaction section comprising at least one, preferably from 1 to 5, fixed bed reactors having n catalyst beds, n being an integer greater than or equal to 1, preferably from 1 to 10, suitably from 2 to 5, said bed(s) each comprising at least one and preferably not more than 10 catalysts. When the reactor comprises several catalyst beds, i.e. at least 2, preferably from 2 to 10, suitably from 2 to 5, said catalyst beds are preferably arranged in series within said reactor.

[0140] If step c) is carried out in a hydrotreating reaction section comprising several reactors, preferably two reactors, these reactors can be operated in series and / or in parallel and / or in variable sequence (i.e. PRS) mode and / or in swing mode. The various optional operating modes, PRS mode (or lead and lag) and swing mode, are well known to the person skilled in the art and are advantageously as defined above.

[0141] In another embodiment of the invention, the hydrotreating reaction section comprises a single fixed bed reactor containing n catalyst beds, n being an integer equal to or greater than 1, preferably between 1 and 10, suitably between 2 and 5.

[0142] In order to avoid carrying catalyst fines and / or catalyst from the hydroconversion step b) into said hydrotreating reaction section b), recovery means can be arranged upstream of said hydrotreating reaction section b) or at its inlet, for example one or more filters or even reactor internals, for example of the filter plate type, can be used. Examples of filter plates are described in patent FR 3 051 375.

[0143] Advantageously, the hydrotreating catalyst used in step c) can be selected from known hydrodemetallization catalysts, hydrotreating catalysts or silicon trapping catalysts, and combinations thereof, which are particularly used for the treatment of petroleum-based fractions. Known hydrodemetallization catalysts are, for example, those described in patents EP 0 113 297, EP 0 113 284, US 5 221 656, US 5 827 421, US 7 119 045, US 5 622 616 and US 5 089 463. Known hydrotreating catalysts are, for example, those described in patents EP 0 113 297, EP 0 113 284, US 6 589 908, US 4 818 743 or US 6 332 976. Known silicon capture catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0144] In particular, said hydrotreating catalyst comprises a support, preferably an inorganic support, and at least one metallic element having hydrodehydrogenation function. Said metallic element having hydrodehydrogenation function advantageously comprises at least one element from group VIII and / or at least one element from group VIB, the at least one element from group VIII being preferably selected from the group consisting of nickel and cobalt, and the at least one element from group VIB being preferably selected from the group consisting of molybdenum and tungsten. The total content of oxides of metallic elements from groups VIB and VIII is preferably between 0.1% and 40% by weight, preferentially between 5% and 35% by weight, relative to the total weight of the catalyst. The weight ratio, expressed as metal oxide, of the metal (or metals) of group VIB relative to the metal (or metals) from group VIII is preferably between 1.0 and 20, advantageously between 2.0 and 10. For example, the hydrotreating reaction section of step c) of the method may comprise a hydrotreating catalyst containing 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO, relative to the total weight of the hydrotreating catalyst, preferably 1% to 8% by weight of nickel, and molybdenum oxide MoO 3 or tungsten oxide WO 3and comprises on the mineral support a total weight of 1.0% to 30% by weight, preferably 3.0% to 29% by weight, of molybdenum and / or tungsten relative to the total weight of the hydrotreating catalyst.

[0145] The support of the hydrotreating catalyst is advantageously selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may advantageously contain a dopant compound, in particular an oxide selected from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and mixtures of these oxides. Preferably, the hydrotreating catalyst comprises an alumina support, preferably an alumina support doped with phosphorus and optionally boron. Phosphorus pentoxide P 2 O 5 If present, its concentration is less than 10% by weight relative to the weight of the alumina, and advantageously is at least 0.001% by weight relative to the total weight of the alumina. 2 O 5 If 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. The alumina used can be, for example, γ (gamma) or η (eta) alumina.

[0146] The hydrotreating catalyst may, for example, be in the form of extrudates.

[0147] Advantageously, the hydrotreating catalyst used in step c) of the process has a specific surface area of ​​250 m 2 / g or more, preferably 300m 2 The specific surface area of ​​the hydrotreating catalyst is advantageously 800 m 2 / g or less, preferably 600m 2 / g or less, especially 400m 2 / g or less. The specific surface area of ​​the hydrotreating catalyst is measured by the BET method, i.e. the specific surface area is determined by nitrogen adsorption according to the standard ASTM D 3663, which is derived from the Brunauer-Emmett-Teller method described in the journal The Journal of the American Chemical Society, 6Q, 309 (1938). Such a specific surface area makes it possible to further improve the removal of pollutants, in particular metals, such as silicon.

[0148] According to another aspect of the present invention, the hydrotreating catalyst further comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to by the term "additive catalyst". In general, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide groups, or other compounds containing a furan ring, or other sugars.

[0149] Advantageously, the hydrotreating step c) not only allows for at least 80% and preferably all hydrogenation of the residual olefins, but also allows for at least partial conversion of other impurities present in the feedstock, such as aromatic compounds, metal compounds, sulfur compounds, nitrogen compounds, halogenated compounds (especially chlorinated compounds), oxygenated compounds.Preferably, the nitrogen content at the outlet of step c) is less than 10 ppm by weight.Step c) may also allow for further reduction of the contaminant content, such as the metal content, in particular the silicon content.Preferably, the metal content at the outlet of step c) is less than 10 ppm by weight, preferably less than 2 ppm by weight, and the silicon content is less than 5 ppm by weight.

[0150] (Hydrocracking step c') (optional) According to one variant, the process of the invention may comprise a hydrocracking step c') carried out on the hydrocarbon fraction comprising compounds with a boiling point above 175°C, either immediately after the hydrotreating step c) or after the fractionation step e).

[0151] Advantageously, step c') carries out a hydrocracking reaction well known to the person skilled in the art, making it possible, more particularly, to convert heavy compounds, such as compounds with a boiling point above 175° C., into compounds with a boiling point below 175° C., contained in the hydrotreated effluent obtained from step c) or separated during the optional fractionation step e). Other reactions can be followed, such as hydrogenation of olefins or aromatics, hydrodemetallization, hydrodesulfurization, hydrodenitrification, etc.

[0152] Compounds with boiling points above 175° C. have a high BMCI and contain more naphthenic, naphthenic and aromatic compounds relative to the lighter compounds, resulting in a higher C / H ratio. This high ratio causes coking in the steam cracker, necessitating a dedicated steam cracking furnace for this fraction. If it is desired to minimize the yield of these heavy compounds (diesel fraction) and maximize the yield of light compounds (naphtha fraction), these compounds can be at least partially converted by hydrocracking to light compounds, which are generally the favored fractions for the steam cracking unit.

[0153] The process of the invention may therefore comprise a hydrocracking step c'), which is carried out in a hydrocracking reaction section using at least one fixed bed, which comprises n catalyst beds, n being an integer equal to or greater than 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with said hydrotreated effluent from step c) and / or the fraction from step e) comprising compounds with a boiling point above 175°C, and a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, with a partial pressure of hydrogen between 1.5 and 20.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to the separation step d).

[0154] Therefore, the average temperature when the hydrocracking reaction section is advantageously used is 250 to 450°C, preferably 320 to 440°C, the hydrogen partial pressure is 1.5 to 20.0 MPa (absolute), preferably 2 to 18.0 MPa (absolute), and the hourly space velocity (HSV) is 0.1 to 10.0 h -1 , preferably 0.1 to 5.0 h -1 , preferentially 0.2~4h -1 The hydrogen coverage in step c) is advantageously determined by the volume (m ) of fresh feedstock fed to step a). 3 ) Hydrogen 80~2000Sm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 200~1800Sm 3 The definitions of the average temperature (WABT), HSV and hydrogen coverage correspond to those described in the selective hydrogenation step a).

[0155] Advantageously, said hydrocracking reaction section is carried out at a pressure which is equivalent to the pressure used in the reaction section of hydrotreating step c).

[0156] Advantageously, said step c') is carried out in a hydrocracking reaction section comprising at least one, preferably between 1 and 5, fixed bed reactors having n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, suitably between 2 and 5, said bed(s) each comprising at least one and preferably not more than 10 hydrocracking catalysts. When the reactor comprises several catalyst beds, i.e. at least 2, preferably between 2 and 10, suitably between 2 and 5, said catalyst beds are preferably arranged in series within said reactor.

[0157] The hydrotreating step c) and the hydrocracking step c') may advantageously be carried out in one and the same reactor or in different reactors, which, if they are carried out in the same reactor, comprise several catalyst beds, the first of which comprises the hydrotreating catalyst(s) and the subsequent catalyst beds comprising the hydrocracking catalyst(s).

[0158] The hydrocracking step can be carried out in one step (step c') or in two steps (steps c') and c''). When it is carried out in two steps, a fractionation of the effluent obtained from the first hydrocracking step c') is carried out, which makes it possible to obtain during steps d) and e) a fraction comprising compounds with a boiling point above 175° C. (diesel fraction), which fraction is introduced into a second hydrocracking step c''), which comprises a dedicated second hydrocracking reaction section different from the first hydrocracking reaction section c'). This configuration is particularly suitable when it is desired to produce only a naphtha fraction.

[0159] The second hydrocracking step c'') is carried out in a hydrocracking reaction section using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, said hydrocracking reaction section being fed at least with the fraction containing compounds having a boiling point above 175°C obtained from step e) and with a gas stream containing hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, with a partial pressure of hydrogen between 1.5 and 20.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to a separation step d). Suitable operating conditions and catalysts used in the second hydrocracking step are those described for the first hydrocracking step. The operating conditions and catalysts used in the two hydrocracking steps can be the same or different.

[0160] The second hydrocracking step is preferably carried out in a hydrocracking reaction section comprising at least one, preferably from 1 to 5, fixed bed reactors having n catalyst beds, n being an integer equal to or greater than 1, preferably from 1 to 10, suitably from 2 to 5, and each of said bed(s) comprising at least one, and preferably not more than 10, hydrocracking catalysts.

[0161] These operating conditions used in the hydrocracking step(s) generally make it possible to obtain a conversion per pass of more than 15% by weight, even more preferably between 20% and 95% by weight, to a product having a minimum of 80% by volume of compounds with a boiling point of less than or equal to 175° C., preferably less than 160° C., and suitably less than 150° C. If the process is carried out in two hydrocracking steps, the conversion per pass in the second step is kept moderate so as to maximize the selectivity for compounds of the naphtha fraction (with a boiling point of less than or equal to 175° C., in particular between 80° C. and less than or equal to 175° C.). The conversion per pass is limited by the use of a high recycle rate throughout the loop of the second hydrocracking step. This rate is defined as the ratio of the feed flow rate of step c″) to the flow rate of the feedstock of step a); preferentially, this ratio is between 0.2 and 4, preferably between 0.5 and 2.5.

[0162] The hydrocracking step(s) thus does not necessarily make it possible to convert all compounds with a boiling point above 175° C. (diesel fraction) into compounds with a boiling point below 175° C. (naphtha fraction). Thus, after fractionation step e), a more or less significant proportion of compounds with a boiling point above 175° C. may remain. To increase the conversion, at least a part of this unconverted fraction can be recycled to step c') as described below or else sent to a second hydrocracking step c''). Another part can be withdrawn. Depending on the operating conditions of the process, said withdrawal can be between 0% and 10% by weight, preferably between 0.5% and 5% by weight, of the fraction comprising compounds with a boiling point above 175° C., relative to the incoming feedstock.

[0163] According to the present invention, the hydrocracking step(s) proceeds in the presence of at least one hydrocracking catalyst.

[0164] The hydrocracking catalyst(s) used in the hydrocracking step(s) are conventional hydrocracking catalysts known to those skilled in the art of bifunctional type combining acid functions, hydrodehydrogenation functions and, optionally, at least one binding matrix. The acid functions are those with a high surface area (typically 150-800 m2) that exhibit surface acidity. 2 / g) of the support, such as halogenated (especially chlorinated or fluorinated) alumina, combinations of oxides of aluminium and boron, amorphous silica-alumina, and zeolites. The hydrodehydrogenation functional groups are provided by at least one metal from group VIB and / or at least one metal from group VIII of the periodic table.

[0165] Preferably, the hydrocracking catalyst(s) contain at least one metal from group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, preferably from cobalt and nickel. Preferably, said catalyst(s) also contain at least one metal from group VIB selected from chromium, molybdenum and tungsten, either alone or in a mixture, preferably from molybdenum and tungsten. Hydrodehydrogenation functions of the NiMo, NiMoW or NiW type are suitable.

[0166] Preferably, the content of metal from group VIII in the hydrocracking catalyst(s) is advantageously between 0.5% and 15% by weight, preferably between 1% and 10% by weight, the percentages being expressed as percentages by weight of the oxide 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.

[0167] Preferably, the content of metal from group VIB in the hydrocracking catalyst(s) is advantageously between 5% and 35% by weight, preferably between 10% and 30% by weight, the percentages being expressed as percentages by weight of the oxide relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is MoO 3 and W.O. 3 It is expressed as:

[0168] The hydrocracking catalyst(s) may also optionally comprise at least one promoter element deposited on the catalyst, the promoter element being selected from the group formed by phosphorus, boron and silicon, optionally from at least one element from group VIIa (chlorine, fluorine are preferred), optionally from at least one element from group VIIB (manganese is preferred), and optionally from at least one element from group VB (niobium is preferred).

[0169] Preferably, the hydrocracking catalyst(s) comprises at least one amorphous or low crystallinity porous inorganic matrix of the oxide type chosen from alumina, silica, silica-alumina, aluminates, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide or clay, alone or as a mixture, preferably alumina or silica-alumina, alone or as a mixture.

[0170] Preferably, the silica-alumina contains more than 50% by weight of alumina, preferably more than 60% by weight of alumina.

[0171] Preferably, the hydrocracking catalyst(s) also optionally comprises a zeolite, which is selected from Y zeolites, preferably USY zeolites, alone or in combination with other zeolites, alone or in mixtures, from Beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48, or ZBM-30 zeolites. Preferably, the zeolite is USY zeolite alone.

[0172] When said catalyst comprises a zeolite, the content of zeolite 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 the percentage of zeolite relative to the total weight of the catalyst.

[0173] Suitable catalysts comprise, and preferably consist of, at least one metal from Group VIB, optionally at least one non-noble metal from Group VIII, at least one promoter element, preferably phosphorus, at least one Y zeolite, and at least one alumina binder.

[0174] An even more preferred catalyst comprises, preferably consists of, nickel, molybdenum, phosphorus, USY zeolite, optionally further beta zeolite, and alumina.

[0175] Another suitable catalyst comprises, and preferably consists of, nickel, tungsten, alumina, and silica-alumina.

[0176] Another suitable catalyst comprises, and preferably consists of, nickel, tungsten, USY zeolite, alumina, and silica-alumina.

[0177] The hydrocracking catalyst may, for example, be in the form of extrudates.

[0178] In one variant, the hydrocracking catalyst used in step c'') comprises a hydrodehydrogenation functional group which comprises, alone or as a mixture, at least one noble metal from group VIII chosen from palladium and platinum. The content of noble metal from group VIII is advantageously between 0.01% and 5% by weight, preferably between 0.05% and 3% by weight, the percentages being expressed as percentages by weight of oxide (PtO or PdO) relative to the total weight of the catalyst.

[0179] According to another aspect of the invention, said hydrogenolysis catalyst also comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to by the term "additive catalyst". In general, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide groups, or also compounds containing a furan ring or sugars.

[0180] The preparation of the catalysts for steps a), b), c), c') or c'') is known and generally comprises a step of impregnation on the support of the metals of group VIII and group VIB, if present, and optionally phosphorus and / or boron, followed by drying and then optionally calcination. In the case of additive-loaded catalysts, the preparation is generally carried out by simply drying, without calcination, after the introduction of the organic compound. The term "calcination" is understood here to mean a heat treatment at a temperature of 200° C. or higher under air or a gas containing oxygen. Before their use in the steps of the method, the catalysts are generally subjected to a sulphurization to form the active entity. The catalysts of step a) can also be catalysts used in their reduced form, and therefore a reduction step is included in their preparation.

[0181] The hydrogen-containing gas stream is fed to the reaction section of a), b), c), c') or c'') and may consist of the hydrogen feed and / or of the recycled hydrogen from step d) and / or from recycled hydrogen, advantageously from step d) or optionally from step e). An additional gas stream, preferably containing hydrogen, is advantageously introduced at the inlet of each reactor, in particular those operating in series, and / or at the inlet of each catalyst bed, starting from the second catalyst bed of the reaction section. These additional gas streams are also called cooling streams. They make it possible to control the temperature in the reactors where the reactions involved are generally highly exothermic.

[0182] Optionally, each of steps a), b), c), c') or c'') may employ a heating section located upstream of the reaction section, in which the incoming effluent is heated to reach an appropriate temperature. Said optional heating section may therefore comprise one or more exchangers (preferably allowing heat exchange between the hydrotreated effluent and the hydrocracked effluent), and / or a preheat oven.

[0183] (Separation step d)) According to the invention, the treatment process comprises a separation step d), advantageously carried out in at least one washing / separation section, to which is fed at least the hydrotreated effluent obtained from step c) or the hydrocracked effluent obtained from optional steps c') and c'') and an aqueous solution, to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent.

[0184] The gaseous effluent obtained on the conclusion of step d) advantageously comprises hydrogen, preferably at least 80% by volume, preferably at least 85% by volume of hydrogen. Advantageously, said gaseous effluent can be at least partially recycled to the selective hydrogenation step a) and / or the hydroconversion step b) and / or the hydrotreating step c) and / or the hydrocracking step c') and / or the hydrocracking step c''), the recycle system may comprise a purification section.

[0185] The aqueous effluent obtained at the end of step d) advantageously contains ammonium salts and / or hydrochloric acid.

[0186] This separation step d) makes it possible in particular to remove ammonium chloride salts, which are formed by reaction between chloride ions and ammonium ions, the chloride ions being in particular released in the form of HCl by hydrogenation of the chlorinated compounds during steps a), b) and c) and subsequently dissolved in water, and the ammonium ions being released in the form of NH by hydrogenation of the nitrogen-containing compounds. 3 in the form of ammonium chloride salts, especially occurring during step c) and / or introduced by injection of the amine and subsequently dissolved in water, thus limiting the risk of plugging flows due to precipitation of ammonium chloride salts, in particular in the transfer lines and / or in the sections of the method of the invention and / or in the lines for transfer to the steam cracker. It also makes it possible to remove the hydrochloric acid formed by reaction of hydrogen ions with chloride ions.

[0187] Depending on the content of chlorinated compounds in the initial feedstock to be treated, a flux containing amines, such as monoethanolamine, diethanolamine and / or monodiethanolamine, can be injected upstream of the selective hydrogenation step a) and / or between the hydroconversion step b) and the hydrotreating step c) and / or between the hydrocracking step c') and the separation step d), preferably upstream of the selective hydrogenation step a), if present, in order to ensure a sufficient amount of ammonium ions to combine with the chloride ions formed during the hydrotreating step, thus limiting the formation of hydrochloric acid and therefore the corrosion downstream of the separation section.

[0188] Advantageously, separation step d) comprises the injection of an aqueous solution, preferably water, into the hydrotreated effluent obtained from step c) or into the hydrocracked effluent obtained from optional steps c') and c''), upstream of the washing / separation section, to at least partially dissolve the ammonium chloride salts and / or hydrochloric acid, thus improving the removal of chlorinated impurities and reducing the risk of clogging caused by the accumulation of ammonium chloride salts.

[0189] The temperature at which separation step d) is advantageously carried out is between 50 and 450° C., preferentially between 100 and 440° C., preferably between 200 and 420° C. It is important to carry out said step in this temperature range (and therefore not to cool the hydroconverted effluent too much), knowing that there may be clogging in the lines due to precipitation of ammonium chloride salts. Advantageously, separation step d) is carried out at a pressure close to that used in steps a) and / or c), preferably between 1.0 and 20.0 MPa, to facilitate the recycling of hydrogen.

[0190] The washing / separation section of step d) can be carried out at least in part in common or separate washing and separation equipment, which are well known (separation drums, pumps, heat exchangers, washing columns, etc. which can be operated at various pressures and temperatures).

[0191] In one optional embodiment of the invention, the separation step d) comprises the injection of an aqueous solution into the hydrotreated effluent obtained from step c), followed by a washing / separation section, advantageously comprising separate phases for obtaining at least one aqueous effluent loaded with ammonium salts, a washed liquid hydrocarbon effluent and a partially washed gaseous effluent. The aqueous effluent loaded with ammonium salts and the washed liquid hydrocarbon effluent are then separated in a knock-out drum to obtain said hydrocarbon effluent and said aqueous effluent. The partially washed gaseous effluent is introduced in parallel into a washing column, where it flows countercurrently against an aqueous stream, preferably of the same nature as the aqueous solution injected into the hydrotreated effluent, which makes it possible to at least partially, preferably completely, remove the hydrochloric acid contained in the partially washed gaseous effluent and thus obtain said gaseous effluent, preferably essentially comprising hydrogen, and an acidic aqueous stream. The aqueous effluent obtained from the knock-out drum may optionally be mixed with the acid aqueous stream and may optionally be used as a mixture with the acid aqueous stream in a water recycle circuit to feed the aqueous solution and / or the aqueous stream in a wash tower upstream of the washing / separation section to separation step d), The water recycle circuit may include a feed of water and / or a basic solution and / or a draw-off allowing the discharge of dissolved salts.

[0192] In another optional embodiment of the invention, separation step d) may advantageously comprise a "high pressure" washing / separation section, which operates at a pressure close to that of the hydrotreating step c) and / or the optional hydrocracking step c'), preferably at a pressure between 1.0 and 20.0 MPa, to facilitate the recycling of hydrogen. This optional "high pressure" section of step d) may be completed with a "low pressure" section to obtain a hydrocarbon liquid fraction free of the part of the gas dissolved at high pressure and intended to be directly processed in the steam cracking process or possibly sent to fractionation step e).

[0193] The gas fraction(s) obtained from the separation step d) may undergo additional purification(s) and separation(s) with the aim of recovering at least one hydrogen-rich gas and / or liquid hydrocarbons. The hydrogen-rich gas may be recycled upstream of steps a) and / or b) and / or c) and / or c') and / or c''), and the liquid hydrocarbons, notably ethane, propane and butane, may advantageously be sent, separately or as a mixture, to one or more furnaces of a steam cracking step f) in order to increase the overall yield of olefins.

[0194] The hydrocarbon effluent obtained from the separation step d) is sent either partially or completely directly to the inlet of the steam cracking unit or to the optional fractionation step e). Preferably, the liquid hydrocarbon effluent is sent partially or completely, preferably completely, to the fractionation step e).

[0195] (Fractionation step e) The process according to the invention may comprise a step of fractionating all or part, preferably all, of the hydrocarbon effluent obtained from step d) to obtain at least one gas stream and at least two liquid hydrocarbon streams, said two fluid hydrocarbon streams being at least one naphtha fraction comprising compounds having a boiling point below 175°C, in particular between 80 and 175°C, and at least one hydrocarbon fraction comprising compounds having a boiling point above 175°C.

[0196] Step e) makes it possible in particular to remove gases dissolved in the liquid hydrocarbon effluent, such as ammonia, hydrogen sulfide and light hydrocarbons having 1 to 4 carbon atoms.

[0197] The optional fractionation step e) is advantageously carried out at a pressure of up to 1.0 MPa (absolute), preferably between 0.1 and 1.0 MPa (absolute).

[0198] According to one embodiment, step e) may be carried out in a section advantageously comprising at least one stripping tower, the stripping tower being equipped with a reflux circuit, the reflux circuit comprising a reflux drum. Said stripping tower is fed with the liquid hydrocarbon effluent obtained from step d) and with a stream of steam. The liquid hydrocarbon effluent obtained from step d) may optionally be heated before entering the stripping tower. The lightest compounds are therefore entrained at the top of the tower and conveyed to a reflux circuit comprising a reflux drum, where a gas / liquid separation is carried out. The gas phase comprising the light hydrocarbons is withdrawn as a gas stream from the reflux drum. The naphtha fraction comprising compounds with a boiling point below 175° C. is advantageously withdrawn from the reflux drum. The hydrocarbon fraction comprising compounds with a boiling point above 175° C. is advantageously withdrawn at the bottom of the stripping tower.

[0199] According to other embodiments, the fractionation step e) can use a stripping column followed by a distillation column or only a distillation column.

[0200] The naphtha fraction containing compounds with a boiling point below 175° C. and the fraction containing compounds with a boiling point above 175° C. may optionally be mixed and sent in whole or in part to a steam cracking unit, at the outlet of which olefins may be (re)formed and participate in the formation of polymers. Preferably, only a portion of said fractions is sent to the steam cracking unit; at least a portion of the remaining portion is optionally recycled to at least one of the steps of the method and / or sent to a storage unit for fuels derived from conventional petroleum-based feedstocks, such as a unit for storage of naphtha, a unit for storage of diesel or a unit for storage of kerosene.

[0201] According to a preferred embodiment, the naphtha fraction containing compounds with a boiling point below 175° C. is sent in whole or in part to a steam cracking unit, whereas the fraction containing compounds with a boiling point above 175° C. is recycled to steps a) and / or b) and / or c) and / or c') and / or sent to a fuel storage unit.

[0202] In a particular embodiment, the optional fractionation step e) may make it possible to obtain, in addition to the gas stream, a naphtha fraction comprising compounds with a boiling point below 175° C., preferably between 80 and 175° C., a diesel fraction comprising compounds with a boiling point above 175° C. and below 385° C., and a hydrocarbon fraction comprising compounds with a boiling point above 385° C., known as the heavy hydrocarbon fraction. The naphtha fraction may be sent in whole or in part to a steam cracking unit and / or a storage unit for naphthas obtained from conventional petroleum-based feedstocks; it may be recycled; the diesel fraction may be sent in whole or in part to a steam cracking unit or a storage unit for diesel obtained from conventional petroleum-based feedstocks or may be recycled; the heavy fraction may be sent, for its part, at least in part to a steam cracking unit or recycled, in particular to the hydroconversion step b).

[0203] In another particular embodiment, the naphtha fraction containing compounds with a boiling point of 175° C. or less obtained from step e) is fractionated to give a heavy naphtha fraction containing compounds with a boiling point of 80-175° C. and a light naphtha fraction containing compounds with a boiling point of less than 80° C., at least a portion of said heavy naphtha fraction being sent to an aromatics complex comprising at least one step of reforming naphtha to give aromatics. According to this embodiment, at least a portion of the light naphtha fraction is sent to a steam cracking step f) described below.

[0204] The gas fraction(s) obtained from the fractionation step e) may form the subject of further purification(s) and separation(s) with the aim of recovering at least the light hydrocarbons, in particular ethane, propane and butanes, which may advantageously be sent separately or as a mixture to one or more furnaces of a steam cracking step f) in order to increase the overall yield of olefins.

[0205] (Recycling of fractions containing compounds with boiling points above 175°C) At least a portion of the fraction comprising compounds with a boiling point above 175° C. obtained from fractionation step e) can be recovered and constitute a recycle stream, which is sent upstream or directly to at least one of the reaction steps of the process according to the invention, in particular to the selective hydrogenation step a) and / or the hydroconversion step b) and / or the hydrotreating step c) and / or the hydrocracking step c′) and / or the hydrocracking step c″). Optionally, a portion of the recycle stream can be sent to optional step a0).

[0206] The recycle stream may be fed to said reaction steps a) and / or b) and / or c) and / or c') and / or c'') in a single injection or may be split into several portions and fed to the reaction section in several injections, i.e. to different catalyst beds.

[0207] Advantageously, the amount of the recycle stream of the fraction containing compounds with a boiling point above 175° C. is adjusted so that the weight ratio between the recycle stream and the feedstock containing pyrolysis oil, i.e. the feedstock to be treated and fed to the entire process, is less than or equal to 10, preferably less than or equal to 5, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, preferably greater than or equal to 0.1. Highly preferably, the amount of the recycle stream is adjusted so that the weight ratio between the recycle stream and the feedstock containing pyrolysis oil is between 0.2 and 5.

[0208] According to one preferred variant, at least a portion of the fraction comprising compounds with a boiling point above 175° C. obtained from the fractionation step e) is sent to the hydroconversion step b).

[0209] According to another preferred variant, at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from fractionation step e) is sent to a hydrocracking step c'), if present.

[0210] According to another preferred variant, at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from fractionation step e) is sent to a second hydrocracking step c″), if present.

[0211] Recycling of part of the cut comprising compounds with a boiling point above 175° C. to at least one of the reaction steps of the process according to the invention or upstream thereof, in particular to the hydroconversion step b) and / or the hydrocracking steps c′) and / or c″), advantageously makes it possible to increase the yield of naphtha cuts with a boiling point below 175° C. Recycling makes it possible to dilute the impurities and also to control the temperature in the reaction step(s) in which the reactions involved may be highly exothermic.

[0212] A purge may be provided for the recycle of the fraction containing compounds with a boiling point above 175° C. Depending on the operating conditions of the process, said purge may be 0-10% by weight, preferably 0.5% to 5% by weight, of the fraction containing compounds with a boiling point above 175° C. relative to the incoming feedstock.

[0213] (Recycling of the hydrocarbon effluent obtained from step d) and / or the naphtha fraction obtained from step e) having a boiling point of 175° C. or less) A part of the hydrocarbon effluent obtained from the separation step d) or a part of the cut having a boiling point below 175° C. obtained from the optional fractionation step e) may be recovered and constitute a recycle stream, which is sent upstream or directly to at least one of the reaction steps of the process according to the invention, in particular to the selective hydrogenation step a) and / or to the hydrotreatment step c). Optionally, a part of the recycle stream may be sent to the optional pretreatment step a0).

[0214] Preferably, at least a portion of the hydrocarbon effluent obtained from the separation step d) or at least a portion of the naphtha cut having a boiling point below 175° C. obtained from the optional fractionation step e) is fed to a hydrotreatment step c).

[0215] Advantageously, the amount of the recycle stream, i.e. the recycled portion of the product obtained, is adjusted so that the weight ratio of the recycle stream to the feedstock comprising pyrolysis oil, i.e. the feedstock to be treated and fed to the overall process, is less than or equal to 10, preferably less than or equal to 5, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, suitably greater than or equal to 0.1. Highly preferably, the amount of the recycle stream is adjusted so that the weight ratio between the recycle stream and the feedstock comprising pyrolysis oil is between 0.2 and 5.

[0216] Advantageously, at the start of the process, a hydrocarbon cut external to the process can be used as a recycle stream. The person skilled in the art will know how to choose said hydrocarbon cut.

[0217] Recycling of part of the product obtained into at least one of the reaction steps of the process according to the invention or upstream thereof advantageously makes it possible, on the one hand, to dilute impurities and, on the other hand, to control the temperature in the reaction step(s) involved, in which the reactions can be highly exothermic.

[0218] The hydrocarbon effluent or the hydrocarbon stream(s) thus obtained by the treatment of plastic pyrolysis oil by the method of the invention exhibits a composition at the inlet of the steam cracking unit that meets the feedstock specifications. In particular, the composition of the hydrocarbon effluent or the hydrocarbon stream(s) is preferably such that: the total content of metallic elements is less than or equal to 5.0 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 suitably less than or equal to 0.5 ppm by weight, The content of silicon (Si) element is 1.0 ppm by weight or less, preferably 0.6 ppm by weight or less, and The iron (Fe) element content is 100 ppb by weight or less, the sulfur content is less than or equal to 500 ppm by weight, preferably less than or equal to 200 ppm by weight; the nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, preferably less than or equal to 5 ppm by weight; - the asphaltene content is 5.0 ppm by weight or less; the total content of elemental chlorine is less than or equal to 10 ppm by weight, preferably less than or equal to 1.0 ppm by weight; The content of olefinic compounds (monoolefins and diolefins) is less than or equal to 5.0% by weight, preferably less than or equal to 2.0% by weight, and suitably less than or equal to 0.1% by weight.

[0219] The content is given as weight percentage (%), parts per million (ppm), or parts per billion (ppb), which is the relative weight concentration relative to the total weight of the stream considered.

[0220] The method according to the invention thus makes it possible to treat plastic pyrolysis oil to obtain an effluent which can be injected in whole or in part into a steam cracking unit.

[0221] (Steam cracking step f) (optional) The hydrocarbon effluent obtained from the separation step d) or at least one of the two liquid hydrocarbon streams obtained from the optional step e) may be sent in whole or in part to a steam cracking step f).

[0222] Advantageously, the gas fraction(s) obtained from the separation step d) and / or the fractionation step e) and containing ethane, propane and butanes may also be sent in whole or in part to a steam cracking step f).

[0223] Said steam cracking step f) is advantageously carried out in at least one pyrolysis furnace, the temperature being between 700 and 900°C, preferably between 750 and 850°C, the pressure being between 0.05 and 0.3 MPa (relative). The residence time of the hydrocarbon compounds is generally less than or equal to 1.0 second (denoted as s), preferably between 0.1 and 0.5 s. Steam is advantageously introduced upstream of the optional steam cracking step e) and after separation (or fractionation). The amount of water advantageously introduced in the form of steam is advantageously between 0.3 and 3.0 kg of water per kg of hydrocarbon compounds by weight at the inlet of step e). Optional step f) is preferably carried out in parallel in several pyrolysis furnaces, in order to adapt the operating conditions to the various streams, in particular those obtained from step e), feeding step f) and to manage the decoking times of the tubes. The furnace comprises one or several tubes arranged in parallel. A furnace may also refer to a group of furnaces operating in parallel. For example, a furnace may be dedicated to the cracking of naphtha fractions containing compounds with boiling points below 175° C.

[0224] The effluents from the various steam cracking furnaces are generally recombined before separation for the purpose of constituting the effluent. It is understood that the steam cracking step f) does not only include the steam cracking furnace, but also sub-steps related to steam cracking that are well known to those skilled in the art. These sub-steps may include, inter alia, heat exchangers, columns and catalytic reactors, as well as a recycle to the furnace. The columns generally make it possible to fractionate the effluent for the purpose of recovering at least one light fraction comprising hydrogen and compounds having 2 to 5 carbon atoms, a fraction comprising pyrolysis gasoline and possibly a fraction comprising pyrolysis oil. The columns allow the separation of the various components of the fractionated light fraction to obtain an ethylene-rich fraction (C 2 fraction) and a propylene-rich fraction (C 3 fraction) and optionally a butene-rich fraction (C 4 The catalytic reactor allows the recovery of at least C 2 Distillate, C 3 Distillate, in fact even C 4 It is particularly possible to carry out hydrogenation of the fractions and of the pyrolysis gasoline. The saturated compounds, in particular those having 2 to 4 carbon atoms, are advantageously recycled to the steam cracker in order to increase the overall yield of olefins.

[0225] This steam cracking step f) makes it possible to obtain at least one effluent containing olefins containing 2, 3 and / or 4 carbon atoms (i.e. C2, C3 and / or C4 olefins) in a satisfactory content, in particular at least 30% by weight, in particular at least 40% by weight and even at least 50% by weight of total olefins containing 2, 3 and 4 carbon atoms, relative to the weight of the steam cracking effluent under consideration. 2 , C 3 and C 4 The olefins may then be advantageously used as polyolefin monomers.

[0226] According to a preferred embodiment of the present invention, a method for processing a feedstock containing pyrolysis oil comprises the following sequence of steps: b) hydroconversion; c) hydrotreating; d) separation; or b) hydroconversion; c) hydrotreating; d) separation; e) fractionation; or b) hydroconversion, c) hydrotreating, d) separation, e) fractionation and recycling of the fraction containing compounds with a boiling point above 175° C. to hydroconversion step b) and / or recycling of the fraction containing compounds with a boiling point below 175° C. to hydrotreating step c). in the given order, producing an effluent at least in part suitable for treatment in a steam cracking unit.

[0227] According to another preferred embodiment of the present invention, a method for processing a feedstock comprising pyrolysis oil comprises the following sequence of steps: b) hydroconversion; c) hydrotreating; c') hydrocracking; d) separation; or b) hydroconversion, c) hydrotreating, c') hydrocracking, d) separation, e) fractionation or b) hydroconversion, c) hydrotreating, c') hydrocracking, d) separation, e) fractionation and recycling of the fraction containing compounds with a boiling point above 175° C. to hydroconversion step b) and / or hydrocracking step c') and / or recycling of the fraction containing compounds with a boiling point below 175° C. to hydrotreating step c). in the given order, producing an effluent at least in part suitable for treatment in a steam cracking unit.

[0228] All embodiments can further comprise, and preferably consist of, a pretreatment step a0).

[0229] All embodiments may further comprise, and preferably consist of, a selective hydrogenation step a).

[0230] All embodiments may further comprise, and preferably consist of, a steam cracking step f).

[0231] (Analysis methods used) The analytical methods and / or standards used to determine the characteristics of the various streams, in particular the feedstocks and effluents to be treated, are known to the person skilled in the art and are specifically listed below for information purposes. Other methods considered equivalent may also be used, in particular equivalent IP, EN or ISO methods.

[0232] [Table 1] (1) MAV method: described in the paper C. Lopez-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.

[0233] (List of Drawings) The information regarding the elements referenced in Fig. 1 allows for a better understanding of the invention, which is not limited to the specific embodiment illustrated in Fig. 1. The various embodiments presented may be used alone or in combination with each other, without any limitations on the combinations.

[0234] FIG. 1 represents a diagram of a specific embodiment of the method of the present invention, which includes: - an optional step a) of selective hydrogenation of a hydrocarbon feedstock (1) obtained by thermal cracking in the presence of a hydrogen-rich gas (2) and, optionally, an amine provided by stream (3); carried out in at least one fixed-bed reactor containing at least one selective hydrogenation catalyst; obtaining an effluent (4); - step b of hydroconversion of the effluent (4) obtained from step a) in the presence of hydrogen (5); carried out in at least one ebullated bed, entrained bed and / or moving bed reactor, the reactor comprising at least one hydroconversion catalyst; obtaining a hydroconverted effluent (6); - a step c of hydrotreating at least a portion of the effluent from step b) in the presence of hydrogen (7); carried out in at least one fixed bed reactor, which reactor contains at least one hydrotreating catalyst, to obtain a hydrotreated effluent (8); said hydrotreating step c) is carried out after the hydroconversion step b), without any step of intermediate separation of the gas stream between the hydroconversion step b) and the hydrotreating step c); - optionally a step c' of hydrocracking at least a part of the effluent obtained from step c) in the presence of hydrogen (9); carried out in at least one fixed bed reactor containing at least one hydrocracking catalyst to obtain a hydrocracked effluent (10); - a step d of separation of the effluent (10); carrying out the separation of the effluent (10) in the presence of an aqueous wash solution (11) making it possible to obtain at least a portion (12) containing hydrogen, an aqueous fraction (13) containing dissolved salts and a hydrocarbon liquid fraction (14), - an optional step e of fractionation of the hydrocarbon liquid fraction (14); making it possible to obtain at least one gas fraction (15), a hydrocarbon fraction (16) comprising compounds having a boiling point below 175°C and a hydrocarbon fraction (17) comprising compounds having a boiling point above 175°C.

[0235] At the end of step d) or step e), at least a portion of the hydrotreated hydrocarbon liquid effluent (16) is sent to a steam cracking process (not shown).

[0236] Optionally, a portion of said hydrocarbon fraction (16) comprising compounds having a boiling point below 175° C. constitutes the recycle streams (16a) and / or (16b) fed to steps a) and / or b), respectively.

[0237] Optionally, a portion of said hydrocarbon fraction (17) comprising compounds with a boiling point above 175° C. constitutes the recycle streams (17a) and / or (17b) fed to steps b) and / or c′), respectively.

[0238] Only the main steps are shown in Figure 1 together with the main flows to allow a better understanding of the invention. It is clearly understood that all equipment required for the operation (drums, pumps, exchangers, ovens / furnaces, columns, etc.) is present even if not shown. It is also understood that, as mentioned above, a hydrogen-rich gas stream (feed or recycle) can be injected at the inlet of each reactor or catalyst bed or between two reactors or two catalyst beds. Means for hydrogen purification and recycling well known to those skilled in the art can also be used.

[0239] (Example) The feedstock (1) treated in this process is a plastic pyrolysis oil having the characteristics shown in Table 2.

[0240] [Table 2]

[0241] The feedstock (1) is subjected to a selective hydrogenation step a) which is carried out in a fixed bed reactor in the presence of hydrogen (2) and a selective hydrogenation catalyst of the NiMo type supported on alumina under the conditions shown in Table 3.

[0242] [Table 3]

[0243] Upon completion of the selective hydrogenation step a), the diolefin content in the feedstock was significantly reduced.

[0244] The effluent (4) obtained from the selective hydrogenation step a) is subjected directly, without separation, to the hydroconversion step b), which is carried out in a boiling bed in the presence of hydrogen (5) and a hydrotreating catalyst of the NiMo type supported on alumina, under the conditions shown in Table 4.

[0245] [Table 4]

[0246] The effluent (6) from the hydroconversion step b) is then sent to a hydrotreatment step c) which is carried out in the presence of hydrogen and a hydrotreatment catalyst of the NiMo type supported on alumina under the conditions shown in Table 5.

[0247] [Table 5]

[0248] The effluent (8) from the hydrotreatment step c) is subjected to a separation step d) and a fractionation step e) comprising a stripping column and a distillation column.

[0249] Table 6 shows the overall yields of the various fractions obtained at the outlet of fractionation step e) relative to the feedstock (1) at the inlet of the process chain.

[0250] [Table 6]

[0251] Compound H 2 S and NH 3 is mainly eliminated in the aqueous phase which is removed in separation step d) in the form of salts.

[0252] The characteristics of the PI-175°C liquid fraction and the 175°C+ liquid fraction obtained after fractionation step e) are shown in Table 7.

[0253] [Table 7]

[0254] Both the PI-175°C liquid fraction and the 175°C+ liquid fraction have compositions compatible with a steam cracking unit for the following reasons: - they do not contain olefins (mono- and di-olefins); - they have very low contents of elemental chlorine (not detectable and 25 ppb by weight, respectively), below the limit required for steam cracking feedstocks; - the metals content, especially iron (Fe), is itself very low (no detectable metals in the PI-175°C fraction and less than 1 ppm by weight in the 175°C+ fraction, no detectable Fe content in the PI-175°C fraction and less than 50 ppb by weight in the 175°C+ fraction) and is below the limits required for steam cracker feed (less than 5.0 ppm by weight for metals, highly preferably less than 1 ppm by weight and less than 100 ppb by weight for Fe); - Finally, they contain sulfur (less than 2 ppm by weight in the PI-175°C fraction and less than 2 ppm by weight in the 175°C+ fraction) and nitrogen (less than 5 ppm by weight in the PI-175°C fraction and less than 10 ppm by weight in the 175°C+ fraction), contents that are much lower than the limits required for steam cracking feedstocks (less than 500 ppm by weight, preferably less than 200 ppm by weight for S and N).

[0255] The resulting PI-175°C liquid fraction and the 175°C+ liquid fraction are then advantageously sent to a steam cracking step f).

Claims

1. 1. A method for processing a feedstock containing pyrolysis oil of plastics and / or solid recycled fuels, comprising the steps of: a) an optional step of selective hydrogenation, in which the feedstock and a gas stream containing hydrogen are fed to a reaction section at least in the presence of at least one selective hydrogenation catalyst at a temperature of 100 to 280° C., a partial pressure of hydrogen of 1.0 to 20.0 MPa (absolute) and an hourly space velocity of 0.3 to 10.0 h －１ obtaining a hydrogenated effluent; b) a step of hydroconversion carried out in a hydroconversion reaction section using at least one ebullated bed reactor, entrained bed reactor and / or moving bed reactor containing at least one hydroconversion catalyst, said hydroconversion reaction section being fed at least with said feedstock or said hydrogenated effluent obtained from step a) and a gas stream containing hydrogen, said hydroconversion reaction section being operated at a temperature of 250-450° C., with a partial pressure of hydrogen of 1.0-20.0 MPa (absolute) and with an hourly space velocity of 0.05-10.0 h －１ obtaining a hydroconverted effluent; c) a hydrotreating step carried out in a hydrotreating reaction section, carried out in at least one fixed bed reactor having n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed with at least a portion of said hydroconverted effluent from step b) and a gas stream comprising hydrogen, said hydrotreating reaction section being carried out at a temperature between 250 and 430° C., with a hydrogen partial pressure between 1.0 and 20.0 MPa (absolute) and with an hourly volumetric rate between 0.1 and 10.0 h －１ obtaining a hydrotreated effluent; said hydrotreating step c) being carried out after the hydroconversion step b) without an intermediate separation step between the hydroconversion step b) and the hydrotreating step c); c') an optional hydrocracking step; The hydrocracking reaction section is carried out using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, and the hydrocracking reaction section is fed with at least the hydrotreated effluent from step c) and / or the fraction from step e) containing compounds having a boiling point above 175° C. and a gas stream containing hydrogen, the average temperature during the hydrocracking reaction section being between 250 and 450° C., the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute), and the hourly space velocity being between 0.1 and 10.0 h －１ obtaining a hydrocracked effluent and sending said hydrocracked effluent to a separation step d); d) separation step; feeding the hydrotreated effluent from step c) or the hydrocracked effluent from step c') and an aqueous solution, said steps being carried out at a temperature between 50 and 450°C; obtaining at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent; e) optionally fractionating all or part of the hydrocarbon effluent obtained from step d) to obtain at least one gaseous effluent, at least one fraction comprising compounds having a boiling point less than or equal to 175° C. and at least one hydrocarbon fraction comprising compounds having a boiling point greater than 175° C.

2. The method of claim 1, comprising a fractionation step e).

3. 2. The process according to claim 1, further comprising a hydrocracking step c').

4. 2. The process of claim 1, comprising the selective hydrogenation step a).

5. 2. The process according to claim 1, wherein at least a portion of the hydrocarbon effluent obtained from the separation step d) or at least a portion of the naphtha cut comprising compounds having a boiling point below 175° C. obtained from the fractionation step e) is sent to the selective hydrogenation step a) and / or to the hydrotreating step c).

6. 2. The process according to claim 1, wherein at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from fractionation step e) is sent to a hydroconversion step b) and / or a hydrocracking step c').

7. 2. The process according to claim 1, comprising a step a0) of pretreatment of the feedstock, said pretreatment step being carried out upstream of the hydrogenation step a), said pretreatment step comprising a filtration step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or an adsorption step.

8. 2. The process according to claim 1, wherein the hydrocarbon effluent obtained from the separation step d) or at least one of the two liquid hydrocarbon streams obtained from step e) is fed, in whole or in part, to a steam cracking step f), which is carried out in at least one pyrolysis furnace, the temperature being between 700 and 900° C. and the pressure being between 0.05 and 0.3 MPa (relative).

9. 2. The process of claim 1, wherein the separation step e) also comprises fractionating the naphtha fraction containing compounds having a boiling point of 175° C. or less into a light naphtha fraction containing compounds having a boiling point of less than 80° C. and a heavy naphtha fraction containing compounds having a boiling point of 80-175° C.

10. 10. The process according to claim 9, wherein at least a portion of the heavy naphtha fraction is sent to an aromatics complex comprising at least one naphtha reforming step and / or at least a portion of the light naphtha fraction is sent to a steam cracking step f).

11. 2. The method of claim 1, wherein the selective hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional element 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.

12. 2. The process according to claim 1, wherein, when step b) is carried out in an ebullated or moving bed, the hydroconversion catalyst of step b) comprises a supported catalyst comprising a Group VIII metal selected from the group formed by Ni, Pd, Pt, Co, Rh and / or Ru, and optionally a Group VIB metal selected from the group formed by Mo and / or W, on an amorphous mineral support selected from the group formed by alumina, silica, silica-alumina, magnesia, clay and mixtures of at least two of these minerals, and, when step b) is carried out in an entrained bed, the hydroconversion catalyst of step b) comprises a dispersed catalyst containing at least one element selected from the group formed by Mo, Fe, Ni, W, Co, V and Ru.

13. 2. The method of claim 1, wherein the hydrotreating catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional element comprising at least one element from Group VIII and / or at least one element from Group VIB.

14. The process also includes a second hydrocracking step c''), which is carried out in a hydrocracking reaction section using at least one fixed bed, which comprises n catalyst beds, n being an integer equal to or greater than 1, each of which comprises at least one hydrocracking catalyst, and which is fed at least with the fraction comprising compounds having a boiling point above 175°C from step e) and a gas stream comprising hydrogen, the temperature of which is between 250 and 450°C, the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute), and the hourly space velocity being between 0.1 and 10.0 h －１ and a hydrocracked effluent is obtained, which is sent to separation step d).

15. 2. The method of claim 1, wherein the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminum, amorphous silica-aluminas and zeolites, and a hydrodehydrogenation functional metal comprising at least one metal from Group VIB selected from chromium, molybdenum and tungsten, either alone or in admixture, and / or at least one metal from Group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

16. 2. The method of claim 1, wherein the feedstock has the following characteristics: the content of aromatic compounds is between 0 and 90% by weight, the content of halogenated compounds is between 2 and 5000 ppm by weight; the content of metallic elements is between 10 and 10,000 ppm by weight; - containing iron element, the content of which is 0 to 100 ppm by weight; The content of elemental silicon is between 0 and 1000 ppm by weight.

17. A product obtainable via the process of claim 1.

18. 18. A product according to claim 17, comprising, relative to the total weight of the product: - metallic elements with a total content of less than or equal to 5.0 ppm by weight, - containing iron element, the content of which is less than or equal to 100 ppb by weight; - elemental silicon with a content of less than or equal to 1.0 ppm by weight, - a content of sulfur not exceeding 500 ppm by weight, - nitrogen with a content of less than or equal to 100 ppm by weight, - elemental chlorine with a content of less than or equal to 10 ppm by weight.

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