Method for treating plastic pyrolysis oil including a hydrogenation step and high-temperature separation

Abstract

The present invention relates to a method for treating plastic pyrolysis oil, comprising: a) hydrogenating said feedstock in a mixture with at least a portion of the liquid effluent obtained from step c) in the presence of hydrogen and a catalyst at a temperature of 140-340° C.; b) hydrotreating said hydrogenated effluent in the presence of hydrogen and a catalyst; c) separating the hydrotreated effluent, said separation being carried out at high temperature and under high pressure to obtain a gaseous effluent and a liquid effluent, and recycling a portion of the liquid effluent upstream of step a); d) feeding at low temperature and under high pressure the other portion of the gaseous and liquid effluents obtained from step c) and an aqueous solution to carry out the separation and obtain a hydrocarbon-based effluent.

Description

[Technical field]

[0001] The present invention relates to a method for treating plastic pyrolysis oil to obtain a hydrocarbon effluent that can be upgraded in a unit for the storage of gasoline, jet or gas oil fuels or as a feedstock for a steam cracking unit. More particularly, the present invention relates to a method for treating a feedstock resulting from the pyrolysis of plastic waste to at least partially remove impurities that said feedstock may contain in relatively large amounts. [Background technology]

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

[0003] Another route for upgrading plastic pyrolysis oils consists in using these pyrolysis oils as feedstock for steam cracking units to (re)produce olefins, which are the constituent monomers of certain polymers. However, plastic wastes are generally mixtures of several polymers, for example mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride or polystyrene. Furthermore, depending on the application, plastics may contain other compounds in addition to the polymers, for example plasticizers, pigments, dyes or even polymerization catalyst residues. Plastic wastes may also contain small amounts of biomass, for example from household waste. The treatment of the wastes, in particular storage, mechanical treatment, sorting and pyrolysis on the one hand, and the storage and transport of pyrolysis oils on the other hand, can cause corrosion. As a result, the oil obtained from the pyrolysis of plastic waste contains many impurities, especially diolefins, metals, especially iron, silicon, as well as halogenated compounds, especially chlorine-based compounds, heteroelements, such as sulfur, oxygen and nitrogen, and insolubles, often at high and incompatible contents with the steam cracking unit or units downstream of the steam cracking unit, especially polymerization and selective hydrogenation processes. These impurities can cause problems of operability, especially corrosion, coking or catalyst deactivation, or also incompatibility in the use of the target polymer. The presence of diolefins can cause problems of instability of the pyrolysis oil, characterized by the formation of gums. The gums and insoluble materials that may be present in the pyrolysis oil can cause clogging problems in processing.

[0004] Moreover, during the steam cracking stage, the yield of light olefins required by the petrochemical industry, especially ethylene and propylene, strongly depends 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 in proportion to the condensed aromatic structure of the analyzed product, naphthenes having an intermediate BMCI between paraffins and aromatics. Overall, a higher yield of light olefins occurs when the paraffin content increases and therefore the BMCI decreases. Conversely, a higher yield of undesirable heavy compounds and / or coke occurs when the BMCI increases.

[0005] In WO 2005 / 023363 a total process for recycling plastic waste is proposed, which is very general and relatively complex, ranging from the very stage of pyrolysis of plastic waste to a steam cracking stage. The process of WO 2005 / 023363 comprises, inter alia, a stage of hydrotreating the liquid phase obtained directly from the pyrolysis, preferably under fairly stringent conditions, in particular stringent in terms of temperature, for example at a temperature of 260-300° C., a stage of separation of the hydrotreating effluent and a subsequent stage of hydrodealkylation of the separated heavy effluent, preferably at high temperature, for example at 260-400° C.

[0006] The unpublished patent application FR 21 / 00.026 describes a method for the treatment of plastic pyrolysis oil, which comprises: a) hydrogenating said feedstock in the presence of at least hydrogen and at least one hydrogenation catalyst at an average temperature between 140 and 340° C.; the outlet temperature of step a) is at least 15° C. higher than the inlet temperature of step a); obtaining a hydrogenated effluent; b) hydrotreating said hydrotreated effluent in the presence of at least hydrogen and at least one hydrotreating catalyst; obtaining a hydrotreated effluent; the average temperature of step b) is higher than the average temperature of step a); c) separation of the hydrotreated effluent in the presence of an aqueous stream at a temperature between 50 and 370° C.; obtaining at least one gaseous effluent, an aqueous liquid effluent and a hydrocarbon liquid effluent.

[0007] In this application FR 21 / 00.026, the hydrogenation of the diolefins and part of the hydrotreating reactions, in particular the hydrogenation of the olefins and part of the hydrodemetallization reactions, in particular the retention of silicon, are carried out in one and the same stage (stage a) at a temperature sufficient to limit the deactivation of the catalyst. This same stage makes it possible to utilize the heat from the hydrogenation reactions, in particular the reactions for the hydrogenation of part of the diolefins, to increase the temperature profile in this stage, thus making it possible to dispense with heating devices between the catalytic hydrogenation section and the catalytic hydrotreating section.

[0008] Temperature control is important in step a) and must satisfy conflicting constraints: on the one hand, the inlet temperature and the temperature throughout the hydrogenation reaction section must be low enough to allow the hydrogenation of diolefins and olefins at the beginning of the hydrogenation reaction section. On the other hand, the inlet temperature of the hydrogenation reaction section must be high enough to prevent catalyst deactivation. Since the hydrogenation reactions, especially the hydrogenation of some of the olefins and diolefins, are highly exothermic, an increasing temperature profile is observed in the hydrogenation reaction section. Thus, a higher temperature at the end of the hydrogenation reaction section allows the hydrodemetallation and hydrodechlorination reactions to take place.

[0009] Therefore, due to the highly exothermic nature of all the reactions carried out in this step a), control of the temperature of the reaction medium has been found to be very important, since an excessively high level of temperature promotes: - Self-sustaining or even runaway reactions due to the effect of thermal acceleration of kinetics, and Undesirable side reactions, such as polymerization, coking of the catalyst and even cracking reactions.

[0010] It is known that recycling a part of the product obtained in at least one of the reaction stages or upstream thereof advantageously makes it possible, on the one hand, to dilute impurities and, on the other hand, to control the temperature of one or more reaction stages, the reactions involved being highly exothermic. Application FR 21 / 00.026 thus describes the possibility of recycling a part of the product obtained after step c) of separation and washing with water (recycle under cold conditions).

[0011] The present invention provides an improvement to this principle of control of exothermicity by recycle, by providing a method scheme for the processing of a feedstock containing plastic pyrolysis oils, the use of a recycle of hot liquid at the inlet of the hydrogenation stage a) allowing precise control of the temperature, improved management of the exothermicity and management of the different reactions taking place in the different catalytic zones. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] International Publication No. 2018 / 055555 Summary of the Invention [Means for solving the problem]

[0013] (Summary of the invention) More specifically, the present invention relates to a method for the treatment of a feedstock containing plastic pyrolysis oil, the method comprising: a) a hydrogenation step carried out in a hydrogenation reaction section, using 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 hydrogenation catalyst, said hydrogenation reaction section being fed at least as a mixture of at least a part of the liquid effluent obtained from separation step c) and a first gas stream containing hydrogen, said hydrogenation reaction section being used at an average temperature of 140-400° C., a hydrogen partial pressure of 1.0-10.0 MPa (abs) and an hourly space velocity of 0.1-10.0 h -1 obtaining a hydrogenated effluent; b) a hydrotreating step carried out in a hydrotreating reaction section, using at least one fixed bed reactor having n catalyst beds, n being an integer equal to or greater than 1, each of which contains at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the hydrotreated effluent from step a) and with a second gas stream containing hydrogen, said hydrotreating reaction section being used at an average temperature between 250 and 430° C. and with a hydrogen partial pressure between 1.0 and 10.0 MPa (abs); obtaining a hydrotreated effluent, c) a separation step, which is fed with the hydrotreated effluent from step b), and which is carried out at a temperature between 200 and 450° C. and at a pressure substantially the same as that of step b); obtaining at least a first gaseous effluent and a liquid effluent; part of the liquid effluent is recycled upstream of step a), d) a separation step, which is fed with the first gaseous effluent, another part of the liquid effluent obtained from step c) and an aqueous solution, said step being carried out at a temperature between 20° C. and less than 200° C. and at a pressure substantially equal to or lower than that of step c); obtaining at least a second gaseous effluent, a liquid effluent and a hydrocarbon effluent, e) optionally a step of fractionation of all or part of the hydrocarbon effluent obtained from step d) to obtain at least a third gaseous effluent and a first hydrocarbon fraction comprising compounds having a boiling point less than or equal to 175° C. and a second hydrocarbon fraction comprising compounds having a boiling point greater than 175° C., f) an optional hydrocracking step carried out in a hydrocracking reaction section; using 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 hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of said hydrocarbon effluent obtained from step d) and / or at least a portion of a second hydrocarbon fraction obtained from step e) comprising compounds having a boiling point above 175° C. and a third gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450° C., with a hydrogen partial pressure between 1.5 and 20.0 MPa (abs) and an hourly space velocity between 0.1 and 10.0 h -1 a first hydrocracked effluent is obtained.

[0014] One of the objectives of the present invention is to control the progress and exothermicity of the reactions in the hydrogenation step a) while ensuring the supply of heat necessary for the initiation and control of the various reactions, in particular the hydrogenation in step a), which requires specific operating conditions in terms of temperature.

[0015] Another object of the invention is to maximize the recovery of energy by recycling at high temperature and pressure a portion of the liquid effluent obtained from step c), since the energy to reach the required inlet temperature in step a) is at least partially contributed by the heat of a portion of the liquid effluent resulting from step c), which not only allows to achieve cost savings but also to reduce CO2 emissions.

[0016] Mixing the feedstock with a portion of the liquid effluent upstream of step a) makes it possible to dilute impurities in the feedstock, but also to indirectly heat the feedstock. Contact with the walls causes hot spots in the feedstock, which leads to the formation of gums and / or coke that cause fouling and an increase in the pressure drop of the system for heating the feedstock and also of the catalyst bed or beds. Indirect heating of the feedstock makes it possible to avoid direct heating of the feedstock on contact with the walls, which would exceed temperatures of 200° C.

[0017] The present invention therefore relates to a hydroprocessing process scheme which simultaneously allows precise control of the reaction temperature used in the hydrogenation stage a) and additionally preferably heating of the system in an indirect manner by the use of a hot liquid recycle upstream of the hydrogenation stage a).

[0018] Another advantage of the process according to the invention is the removal of chlorine in the form of ammonium chloride salts by the combination of a high-temperature separation step c) followed by a low-temperature separation / washing step d). The chloride ions released in the form of HCl by the hydrogenation of chlorinated compounds (hydrodechlorination) during steps a) and b), and the ammonia produced in the form of NH3 by the hydrogenation of nitrogen compounds (hydrodenitrification) during step b), in particular, remain to a large extent in the gas effluent by the high-temperature separation of step c). This is because the high temperature of this separation step c) prevents the precipitation of ammonium chloride salts formed by the reaction between chloride ions and ammonium ions. The separation of the gaseous and liquid effluents at a lower temperature in step d) of a portion thereof leads to the precipitation of these ammonium chloride salts. The washing with water of this step d) makes it possible to dissolve these salts in the aqueous effluent. A hydrocarbon effluent freed from chlorine is thus obtained.

[0019] One advantage of the process according to the invention is that the oil obtained from the pyrolysis of plastic waste is purified from at least a part of its impurities, which makes it possible to hydrogenate it and thus upgrade it, in particular by directly incorporating it in a fuel storage unit or the like, or else by making it suitable for treatment in a steam cracking unit so as to in particular obtain light olefins in good yield, which may act as monomers in the manufacture of polymers.

[0020] Another advantage of the present invention is that it prevents the risk of clogging and / or corrosion of the processing units in which the inventive process is carried out, which risk is exacerbated by the presence of diolefins, metal and halogen compounds, often in large amounts, in the plastic pyrolysis oil.

[0021] The method of the invention thus makes it possible to obtain a hydrocarbon effluent resulting from plastic pyrolysis oil at least partially freed from the impurities of the starting plastic pyrolysis oil, thus limiting operability problems, such as corrosion, coking or catalyst deactivation problems that these impurities may cause, in particular in the steam cracking unit and / or in the units located downstream of the steam cracking unit, in particular the polymerization and hydrogenation units. The removal of at least a portion of the impurities from the oil obtained from the pyrolysis of plastic waste will also make it possible to increase the scope of application of the target polymer and reduce the incompatibility of the application.

[0022] According to an alternative embodiment, the method comprises a fractionation step e).

[0023] According to an alternative embodiment, the process comprises a hydrocracking step f).

[0024] According to an alternative embodiment, in step a), the hydrogen coverage is determined by the volume (m 3 ) Hydrogen 250~800Sm 3 (Sm 3 / m 3 ).

[0025] According to an alternative embodiment, at least a portion of the liquid effluent obtained from the separation stage c) is preheated before being recycled upstream of the hydrogenation stage a).

[0026] According to an alternative embodiment, the weight ratio of the liquid effluent from step c) recycled in step a) to the feedstock comprising plastic pyrolysis oil is between 0.01 and 10.

[0027] According to an alternative embodiment, the method comprises a stage a0) of pretreatment of a feedstock comprising plastic pyrolysis oil, said pretreatment stage being carried out upstream of the hydrogenation stage a) and comprising a filtration stage and / or an electrostatic separation stage and / or a washing stage with an aqueous solution and / or an adsorption stage.

[0028] According to an alternative embodiment, the hydrocarbon effluent obtained from the separation stage d) or at least one of the two liquid hydrocarbon fractions obtained from stage e) is fed in whole or in part to a steam cracking stage g), which is carried out in at least one pyrolysis furnace at a temperature of 700-900° C. and a relative pressure of 0.05-0.3 MPa.

[0029] According to an alternative embodiment, the reaction section of step a) employs at least two reactors operated in a variable sequence mode.

[0030] According to one alternative, a stream containing the amine and / or sulfur compound is injected upstream of step a).

[0031] According to an alternative embodiment, the gaseous effluent obtained from steps c), d) and / or e) and / or the liquid effluent from step c) and / or the hydrocarbon effluent obtained from step d) and / or the first and / or second hydrocarbon fraction obtained from step e) are subjected to a step of adsorption of heavy metals.

[0032] According to an alternative form, said hydrogenation catalyst comprises a support chosen from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group comprising either, on the one hand, at least one element from group VIII and at least one element from group VIB, or, on the other hand, at least one element from group VIII.

[0033] According to an alternative embodiment, 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.

[0034] According to an alternative embodiment, the method further comprises a second hydrocracking stage f'), which is carried out in a hydrocracking reaction section using 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 hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of the first hydrocracked effluent obtained from the first hydrocracking stage f) and with a gas stream comprising hydrogen, said hydrocracking reaction section being used at a temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 MPa (abs) and an hourly space velocity between 0.1 and 10.0 h -1 and obtaining a second hydrocracking effluent.

[0035] According to an alternative form, the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminium, amorphous silica-alumina and zeolites, and a hydrodehydrogenation functional group 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.

[0036] The present invention also relates to the products obtainable, and preferably obtained, by the process of the invention.

[0037] According to this alternative form, the product comprises, based on the total weight of the product: - Metallic elements: total content less than 10.0 ppm by weight, - Contains iron element: content not exceeding 200 ppb by weight, and / or - Silicon element; content not exceeding 5.0 ppm by weight; and / or - Sulphur; not exceeding 500 ppm by weight; and / or - Nitrogen; content not exceeding 100 ppm by weight; and / or - Elemental chlorine; content not exceeding 10 ppm by weight; and / or - Mercury; content less than 5 ppb by weight.

[0038] According to the invention, pressure is absolute pressure, also written abs., and is given in MPa absolute (or MPa(abs)), unless otherwise indicated.

[0039] According to the present invention, the expressions "of between A and B" and "between A and B" are equivalent and mean that both limits of the interval (A, B) are included in the stated range of values. If this is not the case and if both limits are not included in the stated range, such an explanation will be introduced by the present invention.

[0040] Within the meaning of the present invention, the ranges of various parameters for a given stage, such as pressure ranges and temperature ranges, may be used alone or in combination, for example, within the meaning of the present invention, a preferred pressure value range may be combined with a more preferred temperature value range.

[0041] In the following, specific and / or preferred embodiments of the present invention may be described, which may be implemented separately or in combination together, without any limitation on the combination, where this is technically feasible.

[0042] In the following, the groups of chemical elements are 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.

[0043] The metal content is measured by X-ray fluorescence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] (Detailed Description) (Feed material) According to the invention, "plastic pyrolysis oil" is an oil obtained from the pyrolysis of plastics, preferably plastic waste, in particular plastic waste originating from collection and sorting channels, advantageously in liquid form at ambient temperature. It can also be obtained from the pyrolysis of worn tires.

[0045] It especially comprises a mixture of hydrocarbon compounds, in particular paraffins, mono- and / or di-olefins, naphthenes and aromatics. The boiling point of at least 80% by weight of these hydrocarbon compounds is preferably below 700° C., preferably below 550° C. In particular, depending on the origin of the pyrolysis oil, it may comprise up to 70% by weight of paraffins, up to 90% by weight of olefins and up to 90% by weight of aromatics, the sum of paraffins, olefins and aromatics being understood to be 100% by weight of hydrocarbon compounds.

[0046] 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 / cm3 It is.

[0047] Plastic pyrolysis oil can further contain, and generally contains, impurities such as metals, especially iron, silicon or halogenated compounds, especially chlorinated compounds. These impurities can be present in plastic pyrolysis oil in high content, for example, halogen elements (especially chlorine) provided by halogenated compounds up to 350 ppm by weight, even up to 700 ppm by weight, and even up to 1000 ppm by weight, and metals or metalloids up to 100 ppm by weight, and even up to 200 ppm by weight. Alkali metals, alkaline earth metals, transition metals, p-block metals and metalloids can be compared to metallic contaminants and are called metals or metal or metalloid elements. In particular, metals or metal or metalloid elements that may be contained in oil obtained from the pyrolysis of plastic waste include silicon, iron or both elements. The plastic pyrolysis oil may also contain other impurities, such as heteroelements, which are particularly contributed by sulfur compounds, oxygen compounds and / or nitrogen compounds, and the content is generally less than 10,000 ppm by weight of heteroelements, preferably less than 4000 ppm by weight of heteroelements.The plastic pyrolysis oil may also contain other impurities, such as heavy metals, such as mercury, arsenic, zinc and lead, for example up to 100 ppb by weight, even up to 200 ppb by weight of mercury.

[0048] The feedstock for the process according to the invention comprises at least one plastic pyrolysis oil. The feedstock may consist of one or more plastic pyrolysis oils. Preferably, the feedstock comprises at least 50% by weight, preferably 70% to 100% by weight of plastic pyrolysis oil, based on the total weight of the feedstock, i.e. preferably 50% to 100% by weight, preferably 70% to 100% by weight of plastic pyrolysis oil.

[0049] The feedstock for the process according to the invention can include, in addition to one or more plastic pyrolysis oils, conventional petroleum feedstocks or feedstocks obtained from the conversion of biomass, which are then co-processed with the feedstock plastic pyrolysis oil.

[0050] The conventional petroleum feedstock may advantageously be a fraction or mixture of fractions of naphtha, gas oil or vacuum gas oil type.

[0051] The feedstock obtained from the conversion of biomass may advantageously be chosen from vegetable oils, oils from algae or algae oils, fish oils, waste cooking oils and fats of vegetable or animal origin, or mixtures of such feedstocks. The vegetable oils may advantageously be totally or partially unrefined or refined, and may come from plants chosen from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor oil plants, cotton plants, peanut oil, linseed oil and sea kale oil, and all oils derived from sunflower or rapeseed, for example by genetic modification or breeding, although this list is not limiting. The animal fats are advantageously chosen from fats and oils consisting of residues from the food industry or from the catering industry. Frying oils, various animal oils, for example fish oil, tallow or lard, may also be used.

[0052] The feedstock obtained from the conversion of biomass can also be selected from feedstock originating from a process for thermal or catalytic conversion of biomass, for example oils produced from biomass, in particular lignocellulosic biomass, by various liquefaction processes, for example hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material 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).

[0053] The feedstock obtained from the conversion of biomass can also advantageously be chosen from feedstocks obtained from the paper industry.

[0054] Plastic pyrolysis oils can be obtained from thermal or catalytic pyrolysis processes or can also be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0055] (Pre-processing: optional) The feedstock comprising plastic pyrolysis oil can advantageously be pretreated in an optional pretreatment step a0) before the hydrogenation step a) to obtain a pretreated feedstock, which is fed to step a).

[0056] This optional pretreatment step a0) makes it possible to reduce the amount of contaminants and solid particles, in particular the amount of iron and / or silicon and / or chlorine, that may be present in the feedstock containing plastic pyrolysis oil.The optional pretreatment step a0) of the feedstock containing plastic pyrolysis oil is therefore advantageously carried out in particular when the feedstock contains more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of metallic elements and / or solid particles, in particular when the feedstock contains more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, in fact even more than 20 ppm by weight of silicon.Similarly, the optional pretreatment step a0) of the feedstock containing plastic pyrolysis oil is advantageously carried out in particular when the feedstock contains more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of chlorine.

[0057] 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.

[0058] The optional pretreatment stage a0) is advantageously carried out at a temperature between 0 and 150° C., preferably between 5 and 100° C., and at a pressure between 0.15 and 10.0 MPa (abs), preferably between 0.2 and 1.0 MPa (abs).

[0059] According to an alternative embodiment, said optional pretreatment stage a0) is carried out in an adsorption section operated in the presence of at least one adsorbent, preferably of the alumina type, having 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 greater than or equal to 600 m 2 / g or less, especially 400m 2 The 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 periodical The Journal of the American Chemical Society, 6Q, 309 (1938).

[0060] Advantageously, said adsorbent contains less than 1% by weight of metallic elements, preferably it is devoid of metallic elements. Metallic elements of the adsorbent should be understood as meaning elements from groups 6 to 10 of the Periodic Table of the Elements (new IUPAC classification). The residence time of the feedstock in the adsorption section is generally between 1 and 180 minutes.

[0061] The adsorption section of optional step a0) comprises at least one adsorption column, preferably at least two adsorption columns, preferentially 2 to 4 adsorption columns, containing the adsorbent. If the adsorption section comprises two adsorption columns, one operation mode can be a "swing" operation, where one of the columns is on-line, i.e. in operation, while the other column is in reserve. When the adsorbent in the on-line column is used up, this column is isolated, while the in-reserve column is placed on-line, i.e. in operation. The used adsorbent can then be regenerated in situ and / or replaced with fresh adsorbent, and the column containing it can again be placed back on-line where the other column was isolated.

[0062] Another mode of operation is to have at least two columns operating in series. When the adsorbent of the first column is worn out, this first column is isolated and the spent adsorbent is either regenerated in situ or replaced with fresh adsorbent. The column is then put back online in the last position, and so on. This operation is known as the sequence variable mode, or by the term "PRS" for Permutable Reactor System, or alternatively "lead and lag". The combination of at least two adsorption columns makes it possible to overcome possible rapid poisoning and / or clogging of the adsorbent due to the combined action of metal contaminants, diolefins, gums derived from diolefins and insolubles that may be present in the plastic pyrolysis oil to be treated. This is because the presence of at least two adsorption columns advantageously facilitates replacement and / or regeneration of the adsorbent without shutdown of the pretreatment unit, indeed of the process, which thus makes it possible to reduce the risk of clogging and therefore to avoid shutdowns of the unit due to clogging, to control costs and to limit the consumption of adsorbent.

[0063] According to another alternative form, said optional pretreatment stage 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 to separate the phases in order to obtain, on the one hand, a pretreated feedstock and, on the other hand, an aqueous solution containing impurities. Among these equipment there can be, for example, stirred reactors, decanters, mixer-decanters and / or cocurrent or countercurrent washing columns.

[0064] Said optional pretreatment stage a0) can optionally also be fed by at least a portion of the liquid effluent obtained from stage c) of the process and / or a portion of the first hydrocarbon fraction obtained from stage e) comprising compounds with a boiling point below 175° C. and / or a portion of the second hydrocarbon fraction obtained from stage e) comprising compounds with a boiling point above 175° C., either in a mixture with the feedstock comprising plastic pyrolysis oil or separately therefrom. Recycling of at least a portion of the liquid effluent obtained from stage c) makes it possible in particular to increase the settling and thus, after optional filtration, to improve the pretreatment of the feedstock.

[0065] Said optional pretreatment stage a0) thus makes it possible to obtain a pretreated feedstock, which is then fed to the hydrogenation stage a).

[0066] (Hydrogenation step a) (optional) According to the invention, the process comprises a step a) of hydrogenation carried out in a hydrogenation reaction section, using 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 hydrogenation catalyst, said hydrogenation reaction section being fed at least the optionally pretreated feedstock as a mixture with at least a portion of the liquid effluent obtained from step c) and with a first gas stream containing hydrogen, said hydrogenation reaction section being used at an average temperature between 140 and 400° C., with a hydrogen partial pressure between 1.0 and 10.0 MPa (abs) and with an hourly space velocity between 0.1 and 10.0 h -1 and obtaining a hydrogenated effluent.

[0067] Stage a) is in particular carried out under conditions of temperature and hydrogen pressure that allow the hydrogenation of diolefins and olefins to take place at the beginning of the hydrogenation reaction section, while the increasing temperature profile allows hydrodemetallization and hydrodechlorination to take place, in particular at the end of the hydrogenation reaction section. The necessary amount of hydrogen is injected to allow at least a partial hydrogenation of the diolefins and olefins present in the plastic pyrolysis oil, at least a partial hydrodemetallization of the metals, in particular the retention of silicon, and also at least a partial conversion of chlorine (to give HCl). The hydrogenation of diolefins and olefins thus makes it possible to avoid or at least limit the formation of "gums", i.e. the polymerization of diolefins and olefins, and thus the formation of oligomers and polymers that can clog the reaction section of the hydrotreating stage b). During stage a), in parallel with the hydrogenation, the hydrodemetallization, in particular the retention of silicon, makes it possible to limit the deactivation of the catalyst in the reaction section of the hydrotreating stage b). Furthermore, the conditions of stage a) make it possible to convert at least a portion of the chlorine.

[0068] Temperature control is important in this stage and must satisfy conflicting constraints. On the one hand, the inlet temperature and the temperature throughout the hydrogenation reaction section must be sufficiently low to allow hydrogenation of diolefins and olefins at the beginning of the hydrogenation reaction section. On the other hand, the inlet temperature of the hydrogenation reaction section must be sufficiently high to prevent deactivation of the catalyst. Since the hydrogenation reactions, in particular the hydrogenation of some of the olefins and diolefins, are highly exothermic, an increasing temperature profile is observed in the hydrogenation reaction section. This higher temperature at the end of said section makes it possible to carry out the reactions of hydrodemetallization and hydrodechlorination. Therefore, the outlet temperature of the reaction section of stage a) is generally at least 3° C., preferably at least 5° C., higher than the inlet temperature of the reaction section of stage a).

[0069] The temperature in step a), whether this is the average temperature (WABT), the inlet temperature of the reaction section or also the temperature increase in step a) between the inlet and the outlet of the reaction section, can in particular be controlled by the rate of recycling of a part of the liquid effluent resulting from step c) and / or the temperature of the recycled effluent.

[0070] The temperature difference between the inlet and the outlet of the reaction section of stage a) is adapted to the injection of a gaseous (hydrogen) or liquid cooling stream, in particular a portion of the liquid effluent obtained from stage c).

[0071] The temperature difference between the inlet and the outlet of the reaction section of step a) is due exclusively to the exothermic nature of the chemical reaction taking place in the reaction section and therefore corresponds to the non-use of heating means (oven, heat exchanger, etc.).

[0072] The inlet temperature of the reaction section in step a) is between 135 and 397°C, preferably between 240 and 347°C.

[0073] The outlet temperature of the reaction section of step a) is between 138 and 400°C, preferably between 243 and 350°C.

[0074] According to the invention, it is advantageous to carry out the hydrogenation of the diolefins and part of the hydrodemetallation reaction in one and the same stage at a temperature sufficient to limit the deactivation of the catalyst of stage a), which is itself manifested by a decrease in the conversion of the diolefins. This same stage also makes it possible to utilize the heat from the hydrogenation reaction, in particular the reaction for the hydrogenation of part of the olefins and diolefins, in order to have an increasing temperature profile in this stage and to eliminate the need for a heating device between the catalytic hydrogenation section and the catalytic hydrotreating section.

[0075] The reaction section carries out hydrogenation in the presence of at least one hydrogenation catalyst, advantageously at an average temperature (or WABT as defined below) of 140-400°C, preferably 240-350°C, particularly preferably 260-330°C, at a hydrogen partial pressure of 1.0-10.0 MPa (abs), preferably 1.5-8.0 MPa (abs), and at an hourly space velocity (HSV) of 0.1-10.0 h -1 , preferably 0.2 to 5.0 h -1 , highly preferably 0.3~3.0h -1 It is.

[0076] According to the invention, the "average temperature" of the reaction section corresponds to the weight-average bed temperature (WABT), which is well known to the person skilled in the art. The average temperature is advantageously determined depending on the catalyst system used, the equipment and their configuration. The average temperature (or WABT) is calculated in the following way:

[0077]

number

[0078] In the formula, T inlet : temperature of the effluent at the inlet of the reaction section, T outlet: temperature of the effluent at the outlet of the reaction section. Unless otherwise stated, the "average temperature" of the reaction section is given at the conditions at the start of the cycle.

[0079] Hourly space velocity (HSV) is defined herein as the ratio of the hourly volumetric flow rate of the feedstock, optionally including pretreated plastic pyrolysis oil, to the volume of the catalyst(s).

[0080] The hydrogen coverage is defined as the ratio at 15° C. of the volumetric flow rate of hydrogen obtained under standard temperature and pressure conditions to the volumetric flow rate of the “fresh” feedstock, i.e. the feedstock to be treated, optionally pretreated, not taking into account the recycled fraction, in particular the recycled liquid effluent obtained from step c), (volume (m 2 ) of the feedstock). 3 ) per m of H2 standard 3 (Sm 3 (Indicated by).

[0081] The amount of gas stream containing hydrogen (H2) fed to said reaction section of step a) is advantageously determined so that the hydrogen coverage is equal to or greater than the volume (m 3 ) Hydrogen 100~1500Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 200~1000Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 250~800Sm 3 (Sm 3 / m 3 ) is set to be.

[0082] Advantageously, the reaction section of step a) comprises from 1 to 5 reactors, preferably from 2 to 5 reactors, particularly preferably it comprises 2 reactors. The advantage of a hydrogenation reaction section comprising several reactors consists in an optimized treatment of the feedstock and at the same time in reducing the risk of clogging of one or more catalyst beds, thus making it possible to avoid unit shutdowns due to clogging.

[0083] According to a preferred alternative, these reactors are operated in a permutable arrangement, also known as PRS (Permutable Reactor System) or otherwise as "lead-lag". The combination of at least two reactors in a PRS arrangement makes it possible to isolate the reactors, to discharge the spent catalyst, to recharge the reactors with fresh catalyst and to put said reactors back into operation without shutting down the process. The PRS technology is particularly described in patent FR 2 681 871.

[0084] According to a particularly preferred alternative, the hydrogenation reaction section of step a) comprises two reactors operated in variable sequence mode.

[0085] Advantageously, reactor internals can be used to prevent clogging of the reactor or reactors, for example internals of the filter plate type. Examples of filter plates are described in patent FR 3 051 375.

[0086] Advantageously, said hydrogenation catalyst comprises a support, preferably an inorganic support, and a hydrodehydrogenation functional group.

[0087] According to an alternative embodiment, 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 selected from nickel and cobalt, and the at least one element from group VIB being preferably selected from molybdenum and tungsten. According to this alternative embodiment, the total content of metal elements from groups VIB and VIII, expressed as oxides, 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 MoO3 and WO3, respectively.

[0088] The weight ratio of the metal(s) from group VIB to the metal(s) from group VIII, expressed as metal oxides, is preferably 1-20, suitably 2-10.

[0089] According to this alternative form, the reaction section of step a) for example comprises a hydrogenation catalyst comprising 0.5% to 12% by weight of nickel (expressed as nickel oxide NiO relative to the weight of the catalyst), preferably 0.9% to 10% by weight of nickel, and 1% to 30% by weight of molybdenum (expressed as molybdenum oxide MoO3 relative to the weight of the catalyst), preferably 3% to 20% by weight of molybdenum, preferably on an inorganic support, preferably an alumina support.

[0090] According to another alternative form, the hydrodehydrogenation functional group comprises, preferably consists of, at least one element from group VIII, preferably nickel. According to this alternative form, the content of nickel oxide is preferably between 1% and 50% by weight, preferably between 10% and 30% by weight, relative to the weight of the catalyst. This type of catalyst is preferably used in its reduced form, preferably on an inorganic support, preferably on an alumina support.

[0091] The support of the 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 thereof. Preferably, the hydrogenation catalyst comprises an alumina support, possibly doped with phosphorus and optionally boron. If phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight, relative to the weight of the alumina, and advantageously at least 0.001% by weight, relative to the total weight of the alumina. If boron trioxide B2O5 is present, its concentration is less than 10% by weight, relative to the weight of the alumina, and advantageously at least 0.001% by weight, relative to the total weight of the alumina. The alumina used may be, for example, γ (gamma) or η (eta) alumina.

[0092] The hydrogenation catalyst is, for example, in the form of an extrudate.

[0093] Highly preferably, step a) can use at least one hydrogenation catalyst used in step a) which, in addition to the one or more hydrogenation catalysts described above, comprises on an alumina support 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 less than 5% by weight of molybdenum and at least 0.1% by weight of molybdenum, preferably 0.5% by weight of molybdenum, expressed as molybdenum oxide MoO3 relative to the weight of the catalyst. This catalyst is not highly loaded with metals and can preferably be placed upstream or downstream of the one or more hydrogenation catalysts described above.

[0094] Said hydrogenation step a) makes it possible to obtain a hydrogenated effluent, i.e. an effluent with a reduced content of olefins, in particular diolefins, and metals, in particular silicon. The content of impurities, in particular diolefins, of the hydrogenated effluent obtained at the end of step a) is reduced relative to the content of the same impurities, in particular diolefins, contained in the feedstock of the process. Hydrogenation step a) generally makes it possible to convert at least 40%, preferably at least 60%, of the diolefins and also at least 40%, preferably at least 60%, of the olefins contained in the initial feedstock. The heat released by the saturation of the double bonds makes it possible to increase the temperature of the reaction medium and to initiate the hydrotreating reaction, in particular the at least partial removal of other pollutants, such as silicon and chlorine. Preferably, at least 50%, more preferentially at least 75%, of the chlorine and silicon of the initial feedstock are removed during step a). The hydrogenated effluent obtained at the end of hydrogenation step a) is preferably sent directly to hydrotreating step b).

[0095] (hydrotreatment stage b)) According to the invention, the process comprises a hydrotreating step b) carried out in a hydrotreating reaction section, using at least one fixed bed reactor with 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 at least with said hydrogenated effluent from step a) and with a second gas stream containing hydrogen, said hydrotreating reaction section being used at an average temperature between 250 and 430° C., a hydrogen partial pressure between 1.0 and 10.0 MPa (abs) and an hourly space velocity between 0.1 and 10.0 h -1 and obtaining a hydrotreated effluent.

[0096] Advantageously, step b) 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, hydrogenation of the remaining halogenated compounds and olefins, and also hydrodemetallization, are continued.

[0097] The hydrotreating reaction section is advantageously used at a pressure equivalent to that used in the reaction section of the hydrotreating stage a) and generally at an average temperature higher than that of the reaction section of the hydrotreating stage a). The average hydrotreating temperature when the hydrotreating reaction section is advantageously used is therefore 250-430°C, preferably 280-380°C, with a hydrogen partial pressure of 1.0-10.0 MPa (abs) and an hourly space velocity (HSV) of 0.1-10.0 h -1 , preferably 0.1 to 5.0 h -1 , preferentially 0.2~2.0h -1 , preferably 0.2 to 1 hour -1 The hydrogen coverage in step b) is advantageously determined by the volume (m ) of fresh feedstock fed to step a). 3 ) Hydrogen 100~1500Sm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 200~1000Sm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 250~800Sm 3 The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those given above.

[0098] The hydrotreating reaction section is fed at least with the hydrogenated effluent from step a) and with a second gas stream containing hydrogen, advantageously at the level of the first catalyst bed of the first operating reactor. Optionally, the reaction section of step b) can also be fed with at least a portion of the liquid effluent from step c).

[0099] Advantageously, said step b) is carried out in a hydrotreating reaction section comprising at least one, preferably 1 to 5, fixed bed reactors with n catalyst beds, n being an integer greater than or equal to 1, preferably 1 to 10, suitably 2 to 5, said catalyst bed or beds each comprising at least one and preferably not more than 10 hydrotreating catalysts. When a reactor comprises several catalyst beds, i.e. at least 2, preferably 2 to 10, suitably 2 to 5 catalyst beds, said catalyst beds are preferably arranged in series in said reactor.

[0100] If step b) 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 (or 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.

[0101] 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.

[0102] In a particularly preferred variant, the hydrogenation reaction section of stage a) comprises two reactors operated in variable sequence mode and is followed by a hydrotreating reaction section of stage b), which comprises a single fixed bed reactor.

[0103] Advantageously, the hydrotreating catalyst used in step b) can be selected from known hydrodemetallization, hydrotreating or silicon capture catalysts, and combinations thereof, which are used in particular for the treatment of petroleum 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.

[0104] In particular, said hydrotreating catalyst comprises a support, preferably an inorganic support, and at least one metal element having hydrodehydrogenation function. Said metal element having hydrodehydrogenation function advantageously comprises at least one element from group VIII and / or at least one element from group VIB, the element from group VIII being preferably selected from the group consisting of nickel and cobalt, and the element from group VIB being preferably selected from the group consisting of molybdenum and tungsten. The total content, expressed as oxides, of metal 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. When the metal is cobalt or nickel, the metal content is expressed as CоO and NiO, respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MоO3 and WO3, respectively. The weight ratio of the metal or metals from group VIB to the metal or metals from group VIII, expressed as metal oxides, is preferably 1.0 to 20, suitably 2.0 to 10. For example, the hydrotreating reaction section of step b) of the method comprises a hydrotreating catalyst comprising 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 1.0% to 30% by weight of molybdenum, preferably 3.0% to 29% by weight of molybdenum, expressed as molybdenum oxide MoO3 or tungsten oxide WO3 relative to the total weight of the hydrotreating catalyst, on an inorganic support, preferably an alumina support.

[0105] The support of the hydrotreating 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 hydrotreating catalyst comprises an alumina support, preferably an alumina support doped with phosphorus and optionally boron. If phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight, relative to the weight of the alumina, and advantageously at least 0.001% by weight, relative to the total weight of the alumina. If boron trioxide B2O5 is present, its concentration is less than 10% by weight, relative to the weight of the alumina, and advantageously at least 0.001% by weight, relative to the total weight of the alumina. The alumina used may be, for example, γ (gamma) or η (eta) alumina.

[0106] The hydrotreating catalyst may, for example, be in the form of an extrudate.

[0107] Advantageously, the hydrotreating 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 hydrotreating catalyst is advantageously greater than or equal to 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., it is determined by nitrogen adsorption according to the standard ASTM D 3663-78, which is derived from the Brunauer-Emmett-Teller method described in the periodical 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.

[0108] According to another aspect of the invention, the hydrotreating catalyst as described above further 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 carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide groups, or from compounds containing a furan ring, or from sugars.

[0109] Advantageously, the hydrotreating stage b) allows for a minimum of 80%, preferably total, hydrogenation of the residual olefins after the hydrogenation stage a), 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, halogen compounds (especially chlorine compounds) and oxygen compounds.Preferably, the nitrogen content at the outlet of stage b) is less than 10 ppm by weight.Stage b) can also allow for a further reduction in the content of contaminants, such as the content of metals, in particular the silicon content.Preferably, the metal content at the outlet of stage b) 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.

[0110] Depending on the content of sulfur compounds in the initial feedstock to be treated, a stream containing a sulfiding agent can be injected upstream of the hydrogenation step a) and / or the hydrotreating step b) and / or upstream of one of the hydrocracking steps, if present, preferably upstream of the hydrogenation step a) and / or the hydrotreating step b), to ensure a sufficient amount of sulfur to form or maintain the active species (sulfided form) of the catalyst. This activation or sulfiding step is carried out by methods well known to those skilled in the art, advantageously under a sulfo-reducing atmosphere in the presence of hydrogen and hydrogen sulfide. The sulfiding agent is preferably H2S gas, elemental sulfur, CS2, thiols, sulfides and / or polysulfides, hydrocarbon cuts containing sulfur compounds and having a boiling point below 400° C. or any other sulfur-containing compound used for the activation of hydrocarbon feedstocks with the purpose of sulfiding the catalyst. The sulfur-containing compound is advantageously selected from alkyl disulfides, such as dimethyl disulfide (DMDS), alkyl sulfides, such as dimethyl sulfide, thiols, such as n-butylthiol (or 1-butanethiol), and polysulfide compounds of the tert-nonyl polysulfide type. The catalyst can also be sulfurized by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfurized in situ in the presence of a sulfurizing agent and a hydrocarbon feedstock. Highly preferably, the catalyst is sulfurized in situ in the presence of a feedstock doped with dimethyl disulfide.

[0111] (separation step c)) According to the invention, the process comprises a separation stage c) to which the hydrotreated effluent obtained from stage b) is fed, said stage being carried out at a temperature between 200 and 450° C. and at a pressure substantially the same as that of stage b), obtaining at least a first gaseous effluent, a liquid effluent and an aqueous effluent, part of the liquid effluent being recycled upstream of stage a).

[0112] The separation stage c) is a separation stage referred to as high-pressure or medium-pressure high-temperature separation stage, also known to the skilled person under the name HHPS (Hot High Pressure Separator). This stage c) therefore preferably uses a "high-temperature high-pressure" separator, the pressure of which is substantially equal to the operating pressure of stage b). The term "pressure substantially equal to the pressure of stage b)" is understood to mean a pressure of stage b) which has a pressure difference of 0 to 1 MPa, preferably 0.005 to 0.3 MPa, particularly preferably 0.01 to 0.2 MPa relative to the pressure of stage b). Preferably, the pressure of stage c) is the pressure of stage b) reduced by pressure drop.

[0113] The temperature at which the separation is carried out is between 200 and 450° C., preferably between 220 and 330° C., particularly preferably between 240 and 300° C. According to a preferred alternative, with a view to recovering the greatest amount of heat, the separation is carried out at the highest possible temperature, but below the outlet temperature of stage b), which makes it possible to avoid or limit the reheating (and therefore the need for heating) of the effluent from stage b). According to another alternative, the effluent from stage b) can be reheated or cooled before the separation.

[0114] Advantageously, the amount of recycled effluent obtained from step c), i.e. the recycled proportion of the product obtained, is adjusted so that the weight ratio of the recycled stream from step c) to the feedstock containing plastic 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 7, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, in a preferred embodiment greater than or equal to 0.1. Preferably, the amount of recycled liquid effluent obtained from step c) is adjusted so that the weight ratio of the recycled stream to the feedstock containing plastic pyrolysis oil is between 0.01 and 10, preferably between 0.1 and 7, particularly preferably between 0.2 and 5. This recycling rate makes it possible to control the temperature rise in step a), since at a high recycling rate the dilution rate of the feedstock is high and the temperature rise at the beginning of the reaction section of step a) can be controlled as a result by the dilution effect, in particular due to the hydrogenation reaction of the diolefins.

[0115] The separation step can advantageously be carried out in any manner known to the person skilled in the art, for example by a combination of one or more separators (drums) and / or one or more stripping columns, which separators (drums) and / or columns can optionally be fed with a stripping gas, for example a hydrogen-rich gas stream. Preferably, step c) is carried out in a single separator (drum).

[0116] High pressure, high temperature separation makes it possible, on the one hand, to maximize the recovery of energy by high temperature recycling of a part of the liquid effluent, since the energy for reaching the required inlet temperature in stage a) is at least partially provided by the heat of a part of the liquid effluent obtained from stage c), and also makes it possible to reduce, and in fact even to eliminate, the optional preheating by direct heating of the feedstock to temperatures above 200° C., preventing the formation of gums. Furthermore, the fact of recycling at least a part of the liquid effluent at high pressure makes it possible to save energy for the pressurization in stage a).

[0117] The high-pressure, high-temperature separation, on the other hand, makes it possible to minimize the amount of light fractions (hydrocarbon fractions or naphtha containing compounds with a boiling point below 175° C.) contained in the liquid effluent recycled in step a). At this temperature, substantially all of the light fractions (naphtha) of the effluent flow out as gaseous effluent to the separation / washing step d), whereas as liquid phase, the heavy fractions of the feedstock (hydrocarbon fractions or middle distillates containing compounds with a boiling point above 175° C.) are mainly present. Thus, pH2p is advantageous in step a), since the light fractions (naphtha) could partially evaporate and lower the pH2p if they were not at least partially removed during the high-pressure, high-temperature separation. The removal of the light fractions, including naphtha, can possibly be increased by a slight pressure reduction upstream of at least one separator used in step c), even if this use is not preferred as a result of the energy losses associated with the pressure reduction. Another option to increase the removal of the light fractions containing naphtha may consist in carrying out a stripping, for example by injecting a hydrogen-rich gas in step c).

[0118] According to a preferred alternative, at least a portion of the hydrotreated liquid effluent obtained from step c) can be recycled upstream of the hydrogenation step a), advantageously after being either cooled or, if necessary, preheated or kept at the same temperature as the outlet of the separation step c), such that the temperature and flow rate of the feedstock and of the hydrogen are such that the temperature of the inlet stream containing said feedstock as a mixture of at least a portion of said liquid effluent obtained from step c) and the hydrogen-rich gas is between 140 and 400°C, preferably between 220 and 350°C, particularly preferably between 260 and 330°C.

[0119] In the case where at least a portion of the liquid effluent obtained from the separation stage c) is preheated before being recycled upstream of the hydrogenation stage a), said effluent optionally passes through at least one exchanger and / or at least one oven so as to adjust the temperature of said recycled liquid effluent before being recycled upstream of the hydrogenation stage a).

[0120] In the case where at least a part of the liquid effluent obtained from the separation stage c) is cooled before being recycled upstream of the hydrogenation stage a), said effluent optionally passes through at least one exchanger and / or at least one cooling tower so as to adjust the temperature of said recycled liquid effluent before being recycled upstream of the hydrogenation stage a).

[0121] The liquid effluent obtained from step c) can be either cooled or preheated as required or maintained at the same temperature as at the outlet of the separation step c), the use of a recycle of at least a part of such liquid effluent upstream of the hydrogenation step a) thus making it possible to adjust the temperature of the stream entering step a) as required.

[0122] According to an alternative embodiment, the feedstock can be preheated by direct heating to a temperature ranging up to 200° C., preferably up to 180° C., particularly preferably up to 150° C., before being mixed with at least a portion of the effluent resulting from step c). Above this temperature, contact with the walls during direct heating can result in the formation of gums and / or coke, which can cause fouling of the system for heating the feedstock and also of the catalyst bed or beds and an increase in pressure loss. Heating of the feedstock to a temperature above 150° C., preferably above 180° C., particularly preferably above 200° C., is preferably carried out by indirect heating with at least a portion of the effluent resulting from step c).

[0123] Thus, the temperature rise of the feedstock above 150°C, preferably above 180°C, particularly preferably above 200°C, is not brought about by contact with a heated wall but by mixing with a hotter liquid. This makes it possible to limit high temperatures locally, since during heating in a heat exchanger or oven, in order to economically transfer heat, the temperature on the hot side must necessarily be higher than T to reach a given set temperature T. It is well known to those skilled in the art that the heat flux through a wall depends primarily on the temperature difference on both sides of said wall and on the exchange surface area. The smaller the temperature difference between the cold and hot sides, the larger the exchange surface area is for a given amount of exchanged heat. This results in the temperature of the wall in contact with the cold fluid being higher than the desired temperature, commonly known as the skin temperature. Heating by mixing with a hot fluid thus makes it possible to prevent the skin temperature effect and therefore to limit the high temperature zones. This type of heating, by mixing with an inert hot liquid, thus makes it possible to limit undesirable reactions, such as diolefin polymerization (gum formation) and / or coke formation, and to adjust the inlet temperature of the stream in step a), so that the reactions of unsaturation hydrogenation are initiated preferably at the lowest possible temperature, while controlling the exothermicity of these reactions by the effect of dilution of the reactants.

[0124] According to another alternative form, the feedstock is heated entirely by indirect heating with at least a portion of the effluent obtained from step c), in which case the feedstock is not preheated before being mixed with at least a portion of the effluent obtained from step c).

[0125] The regulation of the energy required for the reaction, more particularly the minimum temperature necessary for the activation of the reaction for saturation of the double bonds, is thus mainly achieved by mixing, upstream of step a), said feedstock comprising plastic pyrolysis oil and hydrogen-rich gas with a recycling of a portion of the liquid effluent obtained from the separation step c), which is optionally temperature-regulated, preferably either preheated or cooled, particularly preferably preheated.

[0126] The other heated stream advantageously consists of a hydrogen-rich gaseous effluent derived from the hydrogen feed and / or a gaseous effluent derived from separation stage d). At least a portion of this hydrogen-rich gaseous effluent derived from the hydrogen feed and / or the gaseous effluent obtained from separation stage d) is advantageously injected upstream of stage a), either in a mixture with at least a portion of the liquid effluent obtained from stage c) or separately. The hydrogen-rich gas stream is therefore advantageously either preheated in a mixture with at least a portion of the liquid effluent or preferably preheated separately before mixing, optionally by passing it through at least one exchanger and / or at least one oven or any other heating means known to the skilled person.

[0127] (separation step d)) According to the invention, the treatment method comprises a separation stage d), which is advantageously carried out in at least one washing / separation section, fed with the first gaseous effluent, another part of the liquid effluent obtained from stage c) and an aqueous solution, said stage being carried out at a temperature between 20° C. and less than 200° C. and at a pressure substantially equal to or lower than that of stage c), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent.

[0128] The separation stage d) is carried out in at least one knock-out drum. The knock-out drum is said to be a high or medium pressure low temperature knock-out drum and is also known to the skilled person under the name CHPS (Cold High Pressure Separator). This stage d) therefore preferably uses a "cold high pressure" separator, the pressure of which is substantially equal to the operating pressure of stage c). The term "pressure substantially equal to the pressure of stage c)" is understood to mean a pressure of stage c) having a pressure difference of 0 to 1 MPa, preferably 0.005 to 0.3 MPa, particularly preferably 0.01 to 0.2 MPa, relative to the pressure of stage c). Preferably, the pressure of stage d) is the pressure of stage c) reduced by a pressure drop. The fact that at least part of the separation stage d) is operated at a pressure substantially identical to the operating pressure of stage c), further facilitates the recycling of hydrogen.

[0129] The separation step d) can also be carried out at a pressure lower than the pressure of step c).

[0130] Separation step d) may also comprise a (first) step of separation at a pressure substantially equal to the operating pressure of step c), followed by at least one other separation step, carried out at the same or lower temperature and at a lower pressure than each preceding separation step of step d).

[0131] The temperature at which the separation in step d) is carried out is between 20°C and less than 200°C, preferably between 25 and 120°C, particularly preferably between 30 and 70°C.

[0132] It is important to operate in this temperature range (and therefore not to overcool the hydroconverted effluent) due to the risk of plugging in the lines due to precipitation of ammonium chloride salts.

[0133] The washing / separation section of stage d) can be carried out at least in part in common or separate washing and separation equipment, which are well known (knock-out drums, pumps, heat exchangers, washing columns, etc., which can be operated at various pressures and temperatures). The separation stage d) can comprise, for example, a column for stripping sour water from the withdrawn aqueous fraction (also known as sour water stripper), a column for sour gas washing to purify the hydrogen-rich gas before recycling, a column for stabilization of the washed liquid effluent to remove dissolved gases.

[0134] If one (or two) hydrocracking stages are present (see below), this stage d) can furthermore be fed with at least a portion of the hydrocracked effluent obtained from the optional hydrocracking stage.

[0135] The gaseous effluent obtained on the conclusion of step d) advantageously comprises hydrogen, preferably at least 80% by volume, more preferably at least 85% by volume of hydrogen. Advantageously, said gaseous effluent can be at least partially recycled to the hydrogenation step a) and / or the hydrotreating step b) and / or the hydrocracking step f), if present, the recycle system possibly comprising a purification section.

[0136] The gaseous effluent may also be subjected to one or more additional separations with the aim of recovering at least one hydrogen-rich gas and / or light hydrocarbons, in particular ethane, propane and butane, which may advantageously be sent separately or as a mixture to one or more furnaces of steam cracking stage g) in order to increase the overall yield of olefins.

[0137] The aqueous effluent obtained at the end of step d) advantageously contains ammonium salts and / or hydrochloric acid.

[0138] This separation step d) in particular makes it possible to remove ammonium chloride salts, thus limiting the risk of clogging 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. Ammonium chloride salts are formed by reaction between chloride ions and ammonium ions, the chloride ions being released in the form of HCl by hydrogenation of chlorinated compounds in particular during steps a) and b) and subsequently dissolved in water, and the ammonium ions being generated in the form of NH3 by hydrogenation of nitrogenous compounds in particular during step b) and / or introduced by injection of an amine and subsequently dissolved in water. It also makes it possible to remove the hydrochloric acid formed by reaction of the hydrogen ions with the chloride ions.

[0139] Depending on the content of chlorinated compounds in the initial feedstock to be treated, a stream containing amines, for example monoethanolamine, diethanolamine and / or monodiethanolamine, can be injected upstream of each catalytic stage, preferably upstream of the hydrogenation stage a) and / or hydrotreating stage b), preferably upstream of the hydrogenation stage a), to ensure a sufficient amount of ammonium ions to bind the chloride ions formed during the hydroconversion stages, thus making it possible to limit the formation of hydrochloric acid and therefore the corrosion downstream of the separation section.

[0140] Advantageously, separation stage d) comprises the injection of an aqueous solution, preferably water, into the mixture of the gaseous effluent and another part of the liquid effluent obtained from stage c), upstream of the washing / separation section, so as 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 due to the accumulation of ammonium chloride salts.

[0141] In an optional embodiment of the invention, the separation stage d) comprises the injection of an aqueous solution into the mixture of the gaseous effluent and another part of the liquid effluent obtained from stage c), which is then followed by a washing / separation section, which advantageously comprises a phase of separation making it possible to obtain at least one aqueous effluent to which ammonium salt has been added, a washed liquid hydrocarbon effluent and a partially washed gaseous effluent. The aqueous effluent charged with ammonium salt and the washed liquid hydrocarbon effluent can then be separated in a knock-out drum to obtain said hydrocarbon effluent and said aqueous effluent. The partially washed gaseous effluent can be introduced in parallel into a washing column, where it can flow 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 to obtain said gaseous effluent, preferably said gaseous effluent essentially comprising hydrogen, and an acidic aqueous stream. The aqueous effluent obtained from the knock-out drum can optionally be mixed with the acid aqueous stream and optionally used in a water recycle circuit for feeding the aqueous solution upstream of the washing / separation section and / or the aqueous stream in the washing column to separation stage d), as a mixture with the acid aqueous stream. The water recycle circuit can include a water supply and / or a bleed making it possible to drain the basic solution and / or the dissolved salts.

[0142] The hydrocarbon effluent resulting from the separation stage d) is sent either directly, partially or completely, to the inlet of the steam cracking unit or to the optional fractionation stage e), preferably the liquid hydrocarbon effluent is sent partially or completely, preferably completely, to the fractionation stage e).

[0143] (Fractionation Step e) (Optional) The process according to the invention may comprise a stage of fractionation of all or part, preferably all, of the hydrocarbon effluent obtained from stage d) to obtain at least a third gas stream and at least two liquid hydrocarbon streams, said two liquid hydrocarbon streams being at least a first hydrocarbon fraction comprising compounds having a boiling point below 175° C. (naphtha fraction), in particular between 80 and 175° C., and a second hydrocarbon fraction comprising compounds having a boiling point above 175° C. (middle distillate fraction).

[0144] 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.

[0145] The pressure at which the optional fractionation step e) is advantageously carried out is up to 1.0 MPa (abs), preferably between 0.1 and 1.0 MPa (abs).

[0146] According to one embodiment, step e) may be carried out in a section advantageously comprising at least one stripping tower, the latter being equipped with a 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 water vapor. The liquid hydrocarbon effluent resulting from step d) may optionally be heated before entering the stripping tower. The lightest compounds are therefore entrained in the top of the tower and enter a reflux circuit comprising a reflux drum, where gas / liquid separation takes place. The gas phase comprising the light hydrocarbons is withdrawn as a gas stream from the reflux drum. The hydrocarbon 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.

[0147] According to another embodiment, the fractionation step e) can use a stripping column followed by a distillation column or a distillation column only.

[0148] The first hydrocarbon fraction comprising compounds with a boiling point below 175° C. and the second hydrocarbon fraction comprising compounds with a boiling point above 175° C. can be optionally mixed and sent completely or partially to a steam cracking unit, at the outlet of which olefins can be (re)formed and precipitated in the form 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 into at least one of the stages of the method and / or sent to a fuel storage unit derived from conventional petroleum-based feedstocks, such as a unit for the storage of naphtha, a unit for the storage of diesel or a unit for the storage of kerosene.

[0149] According to a preferred embodiment, the first hydrocarbon fraction comprising compounds with a boiling point below 175° C. is sent completely or partly to a steam cracking unit, while the second hydrocarbon fraction comprising compounds with a boiling point above 175° C. is sent to a hydrocracking stage and / or to a fuel storage unit.

[0150] In a particular embodiment, the optional fractionation step e) may make it possible to obtain, besides the gas stream, a naphtha fraction comprising compounds with a boiling point below 175° C., preferably between 80 and 175° C., a middle distillate 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, completely or partially, to a steam cracking unit and / or to a unit for the storage of naphtha obtained from conventional petroleum feedstocks: it may also be recycled; the middle distillate fraction may be sent, completely or partially, either to a steam cracking unit or to a unit for the storage of diesel obtained from conventional petroleum feedstocks or may also be recycled; the heavy fraction may, for its part, at least partially, be sent to a steam cracking unit or, if a hydrocracking stage is present, to it.

[0151] In another 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 kerosene fraction comprising compounds with a boiling point above 175° C. and below 280° C., a diesel fraction comprising compounds with a boiling point above 280° C. and below 385° C. and a hydrocarbon fraction comprising compounds with a boiling point above 385° C., referred to as the heavy hydrocarbon fraction. The naphtha, kerosene and / or diesel fractions may be sent, completely or partially, either to a steam cracking unit or to the naphtha, kerosene or diesel pools, respectively, obtained from conventional petroleum feedstocks, or may be recycled. The heavy fraction may, for its part, at least partially, be sent to a steam cracking unit or to a hydrocracking stage, if present.

[0152] In another particular embodiment, the naphtha fraction resulting from step e) containing compounds with a boiling point less than or equal to 175° C. is fractionated to give a heavy naphtha fraction containing compounds with a boiling point between 80 and 175° C. and a light naphtha fraction containing compounds with a boiling point less than 80° C., at least a portion of said heavy naphtha fraction being sent to an aromatics complex comprising at least one stage of naphtha reforming with the purpose of obtaining aromatics. According to this embodiment, at least a portion of the light naphtha fraction is sent to the steam cracking step g) described below.

[0153] The gas fraction or fractions obtained from the fractionation stage d) may form the subject of one or more further purification steps and one or more separation steps with the aim at least of recovering 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 stage g) in order to increase the overall yield of olefins.

[0154] (Hydrocracking step f) (optional) According to an alternative embodiment, the process of the invention may comprise a hydrocracking step f), which is carried out after the separation step d) with at least a portion of said hydrocarbon effluent obtained from step d) or with at least a portion of the second hydrocarbon cut comprising compounds having a boiling point above 175° C. after the fractionation step e).

[0155] Advantageously, step f) makes use of hydrocracking reactions well known to those skilled in the art and more particularly makes it possible to convert the heavy compounds contained in the hydrocarbon effluent obtained from fractionation step e), such as compounds having a boiling point above 175° C., into compounds having a boiling point below 175° C. Other reactions can be carried out, such as hydrogenation of olefins or aromatics, hydrodemetallization, hydrodesulfurization, hydrodenitrification, etc.

[0156] Compounds with boiling points above 175° C. have a high BMCI and are rich in naphthenic compounds, naphthenic aromatic compounds and aromatic compounds relative to the lighter compounds, leading to a higher C / H ratio. This high C / H ratio is the cause of coking in the steam cracker, which necessitates a dedicated steam cracking furnace for this fraction. If it is desired to minimize the yield of these heavy compounds (middle distillate fractions) and maximize the yield of light compounds (naphtha fractions), these compounds can be at least partially converted by hydrocracking to light compounds, fractions generally favored by steam cracking units.

[0157] The process of the invention may therefore comprise a hydrocracking step f), which is carried out in a hydrocracking reaction section, using at least one fixed bed reactor with 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 with at least a portion of said hydrocarbon effluent obtained from step d) and / or at least a portion of a second hydrocarbon fraction obtained from step e) comprising compounds having a boiling point above 175° C. and a third gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450° C., with a hydrogen partial pressure between 1.5 and 20.0 MPa (abs) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a first hydrocracked effluent.

[0158] Therefore, the average temperature when the hydrocracking reaction section is advantageously used is 250 to 480°C, preferably 320 to 450°C, the hydrogen partial pressure is 1.5 to 20.0 MPa (abs), preferably 3 to 18.0 MPa (abs), 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 average temperature (WABT), HSV and hydrogen coverage correspond to those given above.

[0159] Advantageously, the pressure under which said hydrocracking reaction section is used is comparable to the pressure used in the reaction section of the hydrogenation stage a) or of the hydrotreatment stage b).

[0160] Advantageously, said step f) is carried out in a hydrocracking reaction section comprising at least one, preferably 1 to 5, fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10 and in a preferred embodiment between 2 and 5, said catalyst bed or beds 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 and in a preferred embodiment between 2 and 5 catalyst beds, said catalyst beds are preferably arranged in series in said reactor.

[0161] The hydrocracked effluent can be at least partially recycled into the hydrotreatment stage a) and / or the hydrotreating stage b) and / or the separation stage d). Preferably, it is recycled into the separation stage d).

[0162] The hydrocracking stage can be carried out in one stage (stage f)) or in two stages (stages f) and f')). When it is carried out in two stages, a separation of the effluent obtained from the first hydrocracking stage f) is carried out making it possible to obtain a hydrocarbon fraction comprising compounds with a boiling point above 175° C. (middle distillate fraction), which is introduced into a second hydrocracking stage f') comprising a dedicated second hydrocracking reaction section different from the first hydrocracking reaction section f). This configuration is particularly suitable when it is desired to produce only a naphtha fraction.

[0163] The second hydrocracking stage f') is carried out in a hydrocracking reaction section using 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 hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of the first hydrocracked effluent obtained from the first hydrocracking stage f) and with a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 MPa (abs) and an hourly space velocity between 0.1 and 10.0 h -1to obtain a second hydrocracking effluent. Suitable operating conditions and catalysts used in the second hydrocracking stage are those described for the first hydrocracking stage. The operating conditions and catalysts used in the two hydrocracking stages can be the same or different.

[0164] The second hydrocracking stage is preferably carried out in a hydrocracking reaction section comprising at least one, preferably 1 to 5, fixed bed reactors having n catalyst beds, n being an integer equal to or greater than 1, preferably 1 to 10, and in a preferred embodiment 2 to 5, and wherein said one or more beds each comprise at least one, and preferably not more than 10, hydrocracking catalysts.

[0165] These operating conditions used in the hydrocracking stage or stages generally make it possible to obtain a conversion per pass of more than 15% by weight, and even more preferably between 20% and 95% by weight, to products having a minimum of 80% by weight of compounds with a boiling point below 175° C., preferably below 160° C., in a preferred embodiment below 150° C. If the process is carried out in two hydrocracking stages, the conversion per pass in the second stage is kept moderate so as to maximize the selectivity for compounds of the naphtha cut (having a boiling point below 175° C., in particular between 80° C. and 175° C.). The conversion per pass is limited by the use of a high recycle rate over the loop of the second hydrocracking stage. This rate is defined as the ratio of the feed flow rate of stage f′) to the flow rate of the feedstock of stage a); preferentially, this ratio is between 0.2 and 4, preferably between 0.5 and 2.5.

[0166] The hydrocracked effluent of the second hydrocracking stage f') can be at least partially recycled to the hydrotreatment stage a) and / or the hydrotreating stage b) and / or the separation stage d). Preferably, it is recycled to the separation stage d).

[0167] The hydrocracking stage or stages therefore do not necessarily make it possible to convert all the hydrocarbon compounds with a boiling point above 175 ° C (middle distillate fraction) into hydrocarbon compounds with a boiling point below 175 ° C (naphtha fraction). After the fractionation stage 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 introduced into a second hydrocracking stage f'). Another part can be bled off. Depending on the operating conditions of the process, said bleed can be between 0% and 10% by weight, preferably between 0.5% and 5% by weight, of the fraction containing compounds with a boiling point above 175 ° C, relative to the incoming feedstock.

[0168] According to the present invention, the hydrocracking step or steps proceed in the presence of at least one hydrocracking catalyst.

[0169] The hydrocracking catalyst or catalysts used in the hydrocracking step or steps are conventional hydrocracking catalysts known to those skilled in the art and are of the bifunctional type combining an acid function with a hydrodehydrogenation function and optionally at least one binding matrix. The acid function is a catalyst having a high specific surface area (typically 150-800 m2) which exhibits surface acidity. 2 / g), such as halogenated (especially chlorinated or fluorinated) aluminas, combinations of oxides of aluminium and boron, amorphous silica-alumina and zeolites. The hydrodehydrogenation function is provided by at least one metal from group VIB and / or at least one metal from group VIII of the periodic table.

[0170] Preferably, the hydrocracking catalyst or catalysts contain a hydrodehydrogenation functional group which comprises at least one metal from group VIII, said metal being selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, preferably from cobalt and nickel. Preferably, said catalyst or catalysts also contain at least one metal from group VIB, said metal being selected, either alone or in mixtures, from chromium, molybdenum and tungsten, preferably from molybdenum and tungsten. Hydrodehydrogenation functional groups of the NiMo, NiMoW or NiW type are suitable.

[0171] Preferably, the content of metal from group VIII in the hydrocracking catalyst or catalysts 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 oxide relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as C0O and Ni0O, respectively.

[0172] Preferably, the content of metal from group VIB in the hydrocracking catalyst or catalysts is advantageously between 5% and 35% by weight, preferably between 10% and 30% by weight, the percentages being expressed as percentages by weight of oxide relative to the total weight of the catalyst. If the metal is molybdenum or tungsten, the metal content is expressed as MoO3, WO3, respectively.

[0173] The one or more hydrocracking catalysts may optionally also comprise, deposited on the catalyst, at least one promoter element selected from the group formed by phosphorus, boron and silicon, optionally at least one element from group VIIa (chlorine, fluorine are preferred), optionally at least one element from group VIIB (manganese is preferred), and optionally at least one element from group VB (niobium is preferred).

[0174] Preferably, the hydrocracking catalyst or catalysts comprise at least one amorphous or poorly crystalline 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 in mixtures, and preferably chosen from alumina or silica-alumina, alone or in mixtures.

[0175] Preferably, the silica-alumina contains more than 50% by weight alumina, more preferably more than 60% by weight alumina.

[0176] Preferably, the hydrocracking catalyst or catalysts optionally also comprise a zeolite, which is selected from Y zeolites, preferably USY zeolites, alone or in combination with other zeolites selected from Beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 or ZBM-30 zeolites, alone or in mixtures, and preferably the zeolite is exclusively USY zeolite.

[0177] In the case where the catalyst comprises a zeolite, the content of zeolite in the hydrocracking catalyst or catalysts 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.

[0178] Suitable catalysts comprise, and preferably consist of, at least one metal from Group VIB, and 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.

[0179] An even more preferred catalyst comprises, and preferably consists of, nickel, molybdenum, phosphorus, USY zeolite, and optionally beta zeolite, and alumina.

[0180] Other suitable catalysts include, and preferably consist of, nickel, tungsten, alumina and silica-alumina.

[0181] Other suitable catalysts include, and preferably consist of, nickel, tungsten, USY zeolite, alumina and silica-alumina.

[0182] The hydrocracking catalyst is, for example, in the form of an extrudate.

[0183] In an alternative embodiment, the hydrodehydrogenation functional group of the hydrocracking catalyst used in the second hydrocracking stage comprises at least one noble metal from group VIII, said metal being chosen from palladium and platinum, either alone or in a mixture, the content of noble metal from group VIII being 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.

[0184] According to another aspect of the invention, the hydrogenolysis 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 "additivated catalyst". Typically, the organic compounds are compounds containing one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide groups, or compounds containing a furan ring, or sugars.

[0185] The preparation of catalysts for the hydrogenation, hydrotreating and hydrocracking stages 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 type catalysts, the preparation is generally carried out by simple 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 stages of the process, the catalysts are generally subjected to a sulfurization to form the active body. The catalysts of stage a) can also be catalysts used in their reduced form, and therefore comprise a reduction step during their preparation.

[0186] The hydrogen-containing gas streams feeding the hydrogenation, hydrotreating and hydrocracking reaction sections can consist of hydrogen feed and / or can consist of recycled hydrogen, in particular obtained from separation stage d). Preferably, additional hydrogen-containing gas streams are advantageously introduced at the inlet of each reactor, in particular reactors 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 fluids. They make it possible to control the temperature in the reactors, where the reactions taking place are generally highly exothermic.

[0187] The hydrocarbon effluent or one or more of said hydrocarbon streams thus obtained by the treatment of plastic pyrolysis oil by the method of the invention exhibits a composition that meets the feedstock specifications at the inlet of the steam cracking unit. In particular, the composition of the hydrocarbon effluent or one or more of said hydrocarbon streams is preferably as follows: the total content of metallic elements is less than or equal to 10.0 ppm by weight, preferably less than or equal to 2.0 ppm by weight, preferentially less than or equal to 1.0 ppm by weight and in a preferred embodiment less than or equal to 0.5 ppm by weight, whereby: The content of silicon (Si) element is 5.0 ppm by weight or less, preferably 1 ppm by weight or less, and in a preferred embodiment, 0.6 ppm by weight or less, and / or the content of iron (Fe) element is 200 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, and / or the nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, and in a preferred embodiment less than or equal to 5 ppm by weight; and / or - the asphaltene content is less than or equal to 5.0 ppm by weight; and / or the total content of elemental chlorine is equal to or less than 10 ppm by weight, preferably less than 1.0 ppm by weight; and / or - the mercury content is less than or equal to 5 ppb by weight, preferably less than or equal to 3 ppb by weight; and / or 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 in a preferred embodiment less than or equal to 0.1% by weight.

[0188] Content is given as the relative concentration by weight, percentage (%) by weight, part(s) per million (ppm) by weight or part(s) per billion (ppb) by weight, relative to the total weight of the stream under consideration.

[0189] The method according to the invention thus makes it possible to treat the plastic pyrolysis oil so as to obtain an effluent which can be injected completely or partially into a steam cracking unit.

[0190] (Heavy metal adsorption step (optional)) Any gaseous effluent and / or any liquid effluent obtained from at least one of the separation steps c) and d) or from the fractionation step e) can be subjected to an optional step of adsorption of heavy metals.

[0191] The gaseous effluent may in particular be a first gaseous effluent obtained from step c) and / or a second gaseous effluent obtained from step d) and / or a third gaseous effluent obtained from step e).

[0192] The liquid effluent may in particular be the liquid effluent obtained from step c) and / or the hydrocarbon effluent obtained from step d) and / or the first and / or second hydrocarbon fraction obtained from step e).

[0193] The optional adsorption step makes it possible to remove or reduce the amount of metal impurities, in particular heavy metals, such as arsenic, zinc, lead, and especially mercury, that may be present in the gaseous and liquid effluents. Metal impurities, in particular heavy metals, are present in the feedstock. Some impurities, in particular mercury-based impurities, can be transformed in one of the steps of the method according to the invention. Their transformed form is susceptible to capture. Their removal or reduction may be particularly necessary when at least a portion of the gaseous and liquid effluents is intended to be sent to a step with strict specifications for metal impurities, for example a steam cracking step, either directly or after being subjected to one or more optional additional steps, for example a fractionation step e).

[0194] The optional step of adsorption of the gaseous effluent obtained from steps c), d) and / or e) and / or the liquid effluent obtained from step c) and / or the hydrocarbon effluent obtained from step d) and / or the first and / or second hydrocarbon fraction obtained from step e) is therefore advantageously carried out, in particular when at least one of these effluents or feedstocks contains more than 20 ppb by weight, in particular more than 15 ppb by weight, of heavy metal elements (As, Zn, Pb, Hg, etc.), in particular when at least one of these effluents or feedstocks contains more than 10 ppb by weight, more particularly more than 15 ppb by weight, of mercury, in particular when at least one of these effluents or feedstocks contains more than 10 ppb by weight, in particular more than 15 ppb by weight, of mercury, in particular when at least one of these effluents or feedstocks contains more than 20 ppb by weight, in particular more than 15 ppb by weight, of heavy metal elements (As, Zn, Pb, Hg, etc.), in particular when at least one of these effluents or feedstocks contains more than 10 ppb by weight, in particular more than 15 ppb by weight, of mercury, in particular more than 15 ppb by weight.

[0195] The optional adsorption step is advantageously carried out at a temperature of 20-150° C., preferably 40-100° C., and at a pressure of 0.15-10.0 MPa (abs), preferably 0.2-1.0 MPa (abs).

[0196] Said optional adsorption step can be carried out by means of any adsorbent known to the person skilled in the art making it possible to reduce the amount of such pollutants.

[0197] According to an alternative form, said optional adsorption step is carried out in an adsorption section operated in the presence of at least one adsorbent comprising a porous support and at least one active phase, said active agent being based on sulfur in elemental form or in the form of a metal sulfide or metal oxide or else of a metal in elemental form.

[0198] The porous support can be chosen without distinction from the series of alumina, silica-alumina, silica, zeolites or activated carbon. Advantageously, the porous support is based on alumina. The specific surface area of ​​the support is generally between 150 and 600 m 2 / g, preferably 200 to 400m 2 / g, more preferably 150 to 350 m 2 The specific surface area of ​​the adsorbent is the surface measured by the BET method as described above.

[0199] The active phase is based on sulfur in elemental form or in the form of metal sulfides or metal oxides or also in elemental form of metals. Preferably, the active phase is in the form of metal sulfides, in particular sulfides of metals from the group selected from copper, molybdenum, tungsten, iron, nickel or cobalt.

[0200] Advantageously, the active phase of the sorbent comprises between 1% and 70% by weight of sulphur, preferably between 2% and 25% by weight and highly preferably between 3% and 20% by weight relative to the total weight of the sorbent.

[0201] Advantageously, the proportion by weight of metal relative to the total weight of the adsorbent is generally between 1% and 60%, preferably between 2% and 40%, in a preferred embodiment between 5% and 30% and highly preferably between 5% and 20%.

[0202] The residence time in the adsorption section is generally from 1 to 180 minutes.

[0203] The adsorption section can include one or more adsorption columns. When the adsorption section includes two adsorption columns, one mode of operation can be "swing" operation, in which one of the columns is on-line, i.e., in operation, while the other column is in reserve. Another mode of operation is to have at least two columns operating in series in a variable sequence mode.

[0204] Preferably, the adsorption section comprises one or more adsorption columns for the gaseous effluents and one or more adsorption columns for the liquid effluents.

[0205] (Steam Cracking Step g) (Optional) The hydrocarbon effluent obtained from the separation stage d) or at least one of the two liquid hydrocarbon streams obtained from the optional stage e) may be sent completely or partly to a steam cracking stage g).

[0206] Advantageously, the ethane, propane and butane-containing gas fraction(s) obtained from the separation stage d) and / or the fractionation stage e) can also be sent completely or partly to a steam cracking stage g).

[0207] Said steam cracking stage g) 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 s), preferably between 0.1 and 0.5 s. Advantageously, steam is introduced upstream of the optional steam cracking stage g), after separation (or fractionation). The water introduced is advantageously in the form of steam, the amount of water being advantageously between 0.3 and 3.0 kg of water per kg of weight of hydrocarbon compounds at the inlet of stage e). Preferably, the optional stage g) is carried out in several pyrolysis furnaces in parallel, the operating conditions being adapted to the various streams feeding stage g), in particular those obtained from stage e), and also to manage the decoking times of the tubes. The furnace comprises one or several tubes arranged in parallel. A furnace may also represent a group of furnaces operating in parallel. For example, a furnace may be dedicated to the cracking of a hydrocarbon fraction containing compounds with a boiling point below 175° C.

[0208] 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 stage g) includes not only the steam cracking furnaces but also sub-stages related to steam cracking that are well known to those skilled in the art. These sub-stages can in particular include heat exchangers, columns and catalytic reactors and recycle to the furnaces. 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 optionally a fraction comprising pyrolysis oil. The columns make it possible to separate the various components of the fractionated light fraction in order to recover at least one fraction rich in ethylene (C2 fraction) and at least one fraction rich in propylene (C3 fraction) and optionally a fraction rich in butenes (C4 fraction). The catalytic reactors in particular make it possible to carry out hydrogenation of the C2, C3 and indeed even C4 fractions and pyrolysis gasoline. Saturated compounds, especially those having from 2 to 4 carbon atoms, are advantageously recycled to the steam cracking furnace to increase the overall yield of olefins.

[0209] This steam cracking stage g) 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 of 30% by weight or more, in particular 40% by weight or more, indeed even 50% by weight or more of the total olefins containing 2, 3 and 4 carbon atoms relative to the weight of the steam cracking effluent under consideration. Said C2, C3 and C4 olefins can then advantageously be used as polyolefin monomers.

[0210] According to a preferred embodiment of the present invention, the method for the treatment of a feedstock containing plastic pyrolysis oil comprises, and preferably consists of, the following steps, preferably linked together in the given order: a) a hydrogenation stage, b) a hydrotreating stage, c) a separation stage and d) a separation / washing stage, - a hydrogenation step a), a hydrotreating step b), a separation step c) and a separation / washing step d) and a fractionation step e), - a hydrogenation step a), a hydrotreating step b), a separation step c) and a separation / washing step d), a fractionation step e) and a step of introducing a hydrocarbon fraction comprising compounds having a boiling point above 175°C into a hydrocracking step f), the hydrocracked effluent being recycled to step d).

[0211] All embodiments may further comprise, and preferably comprise, a pretreatment step a0).

[0212] All embodiments may, and preferably do, further comprise a steam cracking step g).

[0213] All embodiments comprise in step a) the recycling in particular in step a) of at least a part of the liquid effluent obtained from the separation step c).

[0214] (Analysis methods used) The analytical methods and / or standards used to determine the characteristics of the various streams, in particular the feedstocks to be treated and the effluents, are known to the person skilled in the art. They are in particular listed below for information. Other methods that are considered equivalent may also be used, in particular the equivalent IP, EN or ISO methods.

[0215] [Table 1]

[0216] (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.

[0217] (List of Drawings) Identification of the elements referenced in Figures 1-2 allows for a better understanding of the invention, but the invention is not limited to the specific embodiments illustrated in Figures 1-2. The various embodiments presented can be used alone or in combination with each other, and there are no limitations on the combinations.

[0218] FIG. 1 shows a diagram of a particular embodiment of the method of the present invention, which includes: - step a): hydrogenation of a hydrocarbon feedstock (1) obtained from the pyrolysis of plastics, in a mixture with at least a portion (9a) of the recycled liquid effluent obtained from step c), carried out in at least one fixed bed reactor containing at least one hydrogenation catalyst in the presence of a hydrogen-rich gas (2), optionally in the presence of amines provided by stream (3) and optionally in the presence of sulfur compounds provided by stream (4): a hydrogenated effluent (5) is obtained; - step b): hydrotreating the hydrogenated effluent (5) obtained from step a) in the presence of hydrogen (6); this is carried out in at least one fixed bed reactor containing at least one hydrotreating catalyst; a hydrotreated effluent (7) is obtained; - a step c of separation of the hydrotreated effluent (7); carried out at high temperature and pressure (HHPS); obtaining at least a first gaseous effluent (8) and a liquid effluent (9); a part (9a) of the liquid effluent (9) is recycled upstream of step a); - a fractionation step e); carried out in a high pressure, low temperature (CHPS) and fed with the first gaseous effluent (8), with another part (9b) of the liquid effluent obtained from step c) and with an aqueous solution (10), making it possible to obtain at least a second gaseous effluent (11) containing hydrogen, an aqueous effluent (12) containing dissolved salts and a hydrocarbon effluent (13); - an optional step e of fractionation of the hydrocarbon effluent (13); making it possible to obtain at least a third gaseous effluent (14) and at least a first hydrocarbon fraction (15) (naphtha fraction) comprising compounds having a boiling point below 175° C. and a second hydrocarbon fraction (16) (middle distillation fraction) comprising compounds having a boiling point above 175° C.

[0219] At the end of step e), a part of the first hydrocarbon fraction (15) comprising compounds with a boiling point below 175° C. can be sent to a steam cracking process (not shown). Another part of the first hydrocarbon fraction (15) can be fed to the hydrotreating step a) and / or the hydrotreating step b) (not shown).

[0220] Figure 2 shows a diagram of another particular embodiment of the process of the invention, based on the diagram of Figure 1. It comprises in particular a hydrocracking stage f) in which at least a portion of the second hydrocarbon fraction (16) comprising compounds with a boiling point above 175°C obtained from stage e) is fed to this hydrocracking stage f), which is carried out in at least one fixed bed reactor comprising at least one hydrocracking catalyst and fed with hydrogen (17). The hydrocracked effluent (18) is recycled upstream of the separation stage d).

[0221] Instead of injecting the amine stream (3) at the inlet of the hydrogenation stage a), it is possible to inject it at the inlet of the hydrotreating stage b), at the inlet of the separation stage c), at the inlet of the hydrocracking stage f), if present, or else not to inject it, depending on the nature of the feedstock.

[0222] To make the invention easier to understand, only the main stages are represented in Figures 1 and 2 together with the main flows to allow the invention to be better understood. It is clearly understood that all the equipment necessary for the operation (drums, pumps, exchangers, ovens, columns, etc.) is present, even if not represented. It is also understood that 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, as described above. Means well known to those skilled in the art for hydrogen purification and recycling can also be used.

[0223] (Example) (Example 1 (according to the present invention)) The feedstock (1) treated in this process is a plastic pyrolysis oil exhibiting the characteristics indicated in Table 2 (i.e., it contains 100% by weight of said plastic pyrolysis oil).

[0224] [Table 2]

[0225] (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.

[0226] The feedstock (1) and the hydrogen-rich gas (2) are preheated in advance to 100° C. by means of an oven. A part of the liquid effluent obtained from the separation stage c), carried out at 300° C., is preheated to 382° C. and constitutes the hot liquid recycle (9a). The feedstock (1), the hydrogen-rich gas and the hot liquid recycle are mixed and subjected to the hydrogenation stage a). The hydrogenation stage a) is carried out in a fixed bed reactor using a hydrogenation catalyst of the NiMo type supported on alumina under the conditions indicated in Table 3.

[0227] For a flow rate of 6.25 T / h of feed (1) and 18.75 T / h of hot recycle, the amount of heat saved by the hot liquid recycle at 382° C., taking into account the excess heating from 300° C. to 382° C. and compared to the liquid recycle cooled to 40° C., is about 3.6 MW. This saved heat reduces the operational and capital costs required for the process. For this reason, the product obtained from the process is obtained with a lower carbon footprint, i.e. the gas emissions and the greenhouse effect, especially carbon dioxide emissions, are reduced. The heat contribution of the hot liquid recycle also makes it possible not to overheat the feed, since it is heated indirectly by mixing; this makes it possible to limit the formation of gums and / or coke at the inlet of the reactor, which would, in the long term, result in an increase in pressure drop.

[0228] [Table 3]

[0229] The conditions indicated in Table 3 correspond to those at the beginning of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0230] At the end of the hydrogenation step a), the observed degree of conversion (=(initial concentration-final concentration) / initial concentration) is indicated in Table 4.

[0231] [Table 4]

[0232] The hydrogenated effluent (5) obtained from the hydrogenation stage a) is subjected directly, without separation, to a hydrotreating stage b), which is carried out in a fixed bed, in the presence of hydrogen (6) and a hydrotreating catalyst of the NiMo type supported on alumina, under the conditions given in Table 5.

[0233] [Table 5]

[0234] The conditions indicated in Table 5 correspond to those at the beginning of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0235] The hydrotreated effluent (7) obtained from the hydrotreatment stage b) is subjected to a separation stage c), at a pressure substantially identical to that of stage b), the temperature being controlled at 300°C, making it possible to obtain a gaseous effluent and a liquid effluent, a part of the liquid effluent being heated to 382°C and then recycled to the hydrotreatment stage a), this recycled liquid part constituting the hot recycle (9a).

[0236] The first gaseous effluent (8) obtained from c) and the portion (9b) of the liquid effluent obtained from c) that was not recycled to stage a) are mixed and then subjected to a separation stage d): a water stream (10) is injected into the mixture of the gaseous effluent obtained from c) and the portion (9b) of the liquid effluent obtained from c) that was not recycled to stage a); the final mixture reaches a temperature of 40° C. in the HP cold drum, operating at substantially the same pressure as that of stage c), at the outlet of which a hydrogen-rich gas fraction, an aqueous fraction and a washed liquid effluent are obtained. The hydrogen-rich fraction is recycled upstream of the reaction section. The aqueous fraction obtained from the HP cold drum is sent to a stripping column operating at about 0.4 MPa (abs), which gives a stripped aqueous fraction and a sour gas fraction. The washed liquid effluent is treated in a stabilization column operating at about 0.8 MPa (abs), making it possible to obtain light gases and a stabilized liquid hydrocarbon effluent (13). The light gas fraction and the sour gas constitute the second gaseous effluent (11). The yields of the various fractions obtained after separation are given in Table 6 (the yields are expressed as percentages, denoted % w / w, corresponding to the ratio of the amounts by weight of the various products obtained to the weight of the feedstock upstream of stage a).

[0237] [Table 6]

[0238] All or a portion of the resulting liquid fraction can then be upgraded in a steam cracking step to form olefins which can be polymerized to form recycled plastics.

[0239] The process carried out according to the invention results in reduced catalyst deactivation during the hydrogenation step a) and during the hydrotreatment step b) relative to the catalyst deactivation observed according to the prior art. [Brief description of the drawings]

[0240] [Figure 1] 1 shows a diagram of a particular embodiment of the method of the present invention. [Diagram 2] FIG. 2 shows a diagram of another particular embodiment of the method of the invention, based on the diagram of FIG.

Claims

1. 1. A method for the treatment of a feedstock containing plastic pyrolysis oil, the method comprising: a) a hydrogenation step carried out in a hydrogenation reaction section using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, each containing at least one hydrogenation catalyst, to which the feedstock is fed at least as a mixture of at least a portion of the liquid effluent obtained from separation step c) and a first gas stream containing hydrogen, the average temperature during which the hydrogenation reaction section is used being between 140 and 400°C, the hydrogen partial pressure being between 1.0 and 10.0 MPa (abs), and the hourly space velocity being between 0.1 and 10.0 h －１ obtaining a hydrogenated effluent; b) a hydrotreating step carried out in a hydrotreating reaction section using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1 and each containing at least one hydrotreating catalyst, to which the hydrotreating reaction section is fed at least the hydrogenated effluent from step a) and a second gas stream containing hydrogen, the hydrotreating reaction section being used at an average temperature of 250 to 430°C, a hydrogen partial pressure of 1.0 to 10.0 MPa (abs), and an hourly space velocity of 0.1 to 10.0 h －１ obtaining a hydrotreated effluent. c) a separation step, feeding the hydrotreated effluent obtained from step b), said step being carried out at a temperature of 200 to 450°C and at a pressure substantially the same as that of step b); obtaining at least a first gaseous effluent and a liquid effluent; recycling part of the liquid effluent upstream of step a), d) a separation step, feeding the first gaseous effluent, another portion of the liquid effluent obtained from step c) and an aqueous solution, said step being carried out at a temperature between 20°C and less than 200°C and at a pressure substantially equal to or lower than that of step c), to obtain at least a second gaseous effluent, an aqueous effluent and a hydrocarbon effluent; e) optionally a step of fractionation of all or part of the hydrocarbon effluent obtained from step d) to obtain at least a third gaseous effluent and at least a first hydrocarbon fraction comprising compounds having a boiling point of less than or equal to 175° C. and a second hydrocarbon fraction comprising compounds having a boiling point of more than 175° C., f) an optional hydrocracking step carried out in a hydrocracking reaction section using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, each containing at least one hydrocracking catalyst, to which at least a portion of the hydrocarbon effluent obtained from step d) and / or at least a portion of the second hydrocarbon fraction obtained from step e) comprising compounds having a boiling point above 175°C and a third gas stream comprising hydrogen are fed, the average temperature during which the hydrocracking reaction section is between 250 and 450°C, the hydrogen partial pressure is between 1.5 and 20.0 MPa (abs), and the hourly space velocity is between 0.1 and 10.0 h －１ obtaining a first hydrocracked effluent.

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

3. 10. The process of claim 1, comprising a hydrocracking step f).

4. In step a), the hydrogen coverage is determined by the volume (m ３ ) hydrogen 250-800 Sm ３ (Sm ３ / m ３ 2. The method of claim 1 , wherein

5. 2. The process according to claim 1, wherein at least a portion of the liquid effluent obtained from the separation step c) is preheated before being recycled upstream of the hydrogenation step a).

6. 2. The method of claim 1, wherein the weight ratio of the liquid effluent obtained from step c) recycled to step a) to the feedstock comprising plastic pyrolysis oil is 0.01 to 10.

7. 2. The method according to claim 1, comprising a step a0) of pretreatment of a feedstock comprising plastic pyrolysis oil, the 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 washing step with an aqueous solution and / or an adsorption step.

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

9. 10. The process of claim 1, wherein the reaction section of step a) employs at least two reactors operated in a variable sequence mode.

10. 10. The process of claim 1, wherein a stream containing an amine and / or a sulfur compound is injected upstream of step a).

11. 2. The process according to claim 1, wherein the gaseous effluent obtained from steps c), d) and / or e), and / or the liquid effluent from step c) and / or the hydrocarbon effluent obtained from step d) and / or the first and / or second hydrocarbon fraction obtained from step e) is subjected to a step of adsorption of heavy metals.

12. 2. The method of claim 1, wherein the 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.

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. a second hydrocracking step f') carried out in a hydrocracking reaction section using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, each containing at least one hydrocracking catalyst, to which at least a portion of the first hydrocracked effluent from the first hydrocracking step f) and a gas stream comprising hydrogen are fed, the hydrocracking reaction section being used at a temperature of 250 to 450°C, a hydrogen partial pressure of 1.5 to 20.0 MPa (abs), and an hourly space velocity of 0.1 to 10.0 h －１ and obtaining a second hydrocracked effluent.

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

16. A product obtained by the method according to any one of claims 1 to 15.

17. The product of claim 16, comprising, by total weight of the product: Metal elements: the total content is less than or equal to 10.0 ppm by weight; - containing the element iron, the content of which is less than or equal to 200 ppb by weight, and / or silicon element: the content is equal to or less than 5.0 ppm by weight, and / or sulfur: the content is less than or equal to 500 ppm by weight, and / or Nitrogen: the content is less than or equal to 100 ppm by weight, and / or elemental chlorine: the content is less than or equal to 10 ppm by weight, and / or - Mercury: The content is not more than 5 ppb by weight.

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