Method for treating plastic pyrolysis oil, including a one-step hydrocracking process.

Abstract

The present invention relates to a method for processing plastic pyrolysis oil, the method comprising: (a) selectively hydrogenating the feedstock in the presence of at least hydrogen and at least one selective hydrogenation catalyst; (b) hydrotreating the hydrotreated effluent in the presence of at least hydrogen and at least one hydrotreating catalyst to obtain a hydrotreated effluent; (c) hydrocracking the hydrotreated effluent in the presence of at least hydrogen and at least one hydrocracking catalyst to obtain a hydrocracked effluent; and (d) separating the hydrocracked effluent in the presence of an aqueous stream at a temperature between 50 and 370°C to obtain at least one gaseous effluent, a liquid aqueous effluent, and a liquid hydrocarbon effluent.

Description

[Technical Field]

[0001] The present invention relates to a method for processing plastic pyrolysis oil to obtain a hydrocarbon-based effluent that can be upgraded, for example, by being directly incorporated into naphtha or diesel pools, or by being upgraded as feedstock for steam cracking units. More specifically, the present invention relates to a method for processing feedstock obtained from the pyrolysis of plastic waste to at least partially remove impurities that may be present in relatively large amounts in the feedstock, particularly olefins (monoolefins and diolefins), metals, especially silicon, and halogens, especially chlorine, and to enable the feedstock to be hydrogenated and upgraded.

[0002] The method according to the present invention makes it possible to treat plastic pyrolysis oil to obtain an effluent that can be injected whole or partially into a steam cracking unit. The method according to the present invention makes it possible to upgrade plastic pyrolysis oil while simultaneously reducing coke formation, and therefore reducing the risk of clogging and / or premature loss of activity of the catalyst(s) used in the steam cracking unit, and reducing the risk of corrosion. [Background technology]

[0003] Plastics obtained from collection and sorting channels may be subjected to a pyrolysis process, which yields, in particular, pyrolysis oil. These plastic pyrolysis oils are commonly burned for power generation and / or used as fuel for industrial boilers or urban heating.

[0004] Another route to upgrading plastic pyrolysis oils is to use them as feedstock for steam decomposition units to (re)generate olefins, which are constituent monomers of certain polymers. However, plastic waste is generally a mixture of several polymers, such as polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, and polystyrene. Furthermore, depending on its application, plastics may contain other compounds in addition to polymers, such as plasticizers, pigments, colorants, or polymerization catalyst residues. Plastic waste may also contain small amounts of biomass, such as biomass derived from household waste. As a result, the oil obtained from the pyrolysis of plastic waste contains a large amount of impurities, particularly diolefins, metals, especially silicon, or halogenated compounds, especially chlorine-based compounds, heteroatoms, such as sulfur, oxygen, and nitrogen, as well as insoluble substances. The content of these impurities is often high and unsuitable for steam decomposition units or units located downstream of steam decomposition units, particularly polymerization methods and selective hydrogenation methods. These impurities can lead to handling problems, and in particular, problems of corrosion, coking, or catalyst deactivation, or problems of unsuitability for the target polymer's application. The presence of diolefins can also lead to instability of the pyrolysis oil, which is characterized by the formation of gummy substances. Gummy substances and insoluble materials that may be present in the pyrolysis oil can cause clogging problems in this method.

[0005] Furthermore, the yields of light olefins, particularly ethylene and propylene, required for petrochemicals during the steam cracking process, depend heavily on the quality of the feedstock delivered for steam cracking. The Bureau of Mines Correlation Index (BMCI) is often used to characterize hydrocarbon fractions. Generally, the yield of light olefins increases when the paraffin content improves and / or when the BMCI decreases. Conversely, the yield of undesirable heavy compounds and / or coke increases when the BMCI increases.

[0006] Patent Document 1 proposes a very general and relatively complex overall method for recycling plastic waste, ranging from a thermal decomposition step to a steam decomposition step. The method of Patent Document 1 includes, in particular, a step of hydrogenating the liquid phase obtained directly from the thermal decomposition, preferably under fairly strict conditions, particularly with respect to temperature, for example, at a temperature of 260-300°C; a step of separating the hydrogenation effluent; and a subsequent step of hydrogen dealkylation of the separated heavy effluent, preferably at a high temperature, for example, 260-400°C.

[0007] An unpublished patent application FR 20 / 01758 describes a method for treating plastic pyrolysis oil, which includes the following: a) A step of selectively hydrogenating the feed material in the presence of hydrogen and a selective hydrogenation catalyst to obtain a hydrogenated effluent; b) A step of hydrogenating the hydrogenated effluent in the presence of hydrogen and a hydrogenation catalyst to obtain a hydrogenated effluent; c) A process of separating hydrogenated effluent at a temperature of 50-370°C in the presence of an aqueous flow to obtain gaseous effluent, aqueous liquid effluent, and hydrocarbon-based liquid effluent; d) Optionally, fractionating all or part of the hydrocarbon-based effluent obtained from step c) to obtain one gas stream and at least two hydrocarbon-based streams, wherein the two hydrocarbon-based streams may be a naphtha fraction and a heavier fraction; e) A recycling step comprising recovering at least one fraction of the hydrocarbon-based effluent obtained from the separation step c) or a fraction of the hydrocarbon-based stream obtained from the fractionation step d) and / or a hydrocarbon-based stream obtained from the fractionation step d) and sending it to the selective hydrogenation step a) and / or the hydrotreating step b).

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

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

[0010] The heavier fraction can be sent to the steam cracking unit, but few refineries prefer this option. The reason is that the heavier fraction has a high BMCI and contains more naphthenic, naphthene-aromatic and aromatic compounds relative to the naphtha fraction, resulting in a higher C / H ratio. A high ratio causes coking in the steam cracker, thus requiring a dedicated steam cracker for this fraction. Furthermore, steam cracking of such heavy fractions produces less of the desired products, especially ethylene and propylene, but more pyrolysis gasoline.

[0011] Therefore, it would be advantageous to minimize the yield of the heavy fraction and maximize the yield of the naphtha fraction by converting the heavy fraction to the naphtha fraction, at least partially, through hydrocracking. This allows for obtaining more naphtha, which is preferably sent to steam cracking to produce more olefins, while simultaneously reducing the risk of clogging during the processing of plastic pyrolysis oil, as described in the prior art, and the risk of large amounts of coke formation and / or corrosion encountered in subsequent processes (one or more), such as the steam cracking of plastic pyrolysis oil. The heavy fraction that is not converted by hydrocracking is preferably upgraded by recycling it back into the hydrocracking process for re-cracking. Furthermore, the C2-C4 compounds produced during hydrocracking may be sent to steam cracking, which makes it possible to improve the yield of light olefins (ethylene and propylene). Overall, the olefin yield is at least maintained or even improved, while at the same time the need for a steam cracking furnace dedicated to the heavy fraction is diminishing. [Prior art documents] [Patent Documents]

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

[0013] (Summary of the invention) The present invention relates to a method for processing a feedstock containing plastic pyrolysis oil, the method comprising: a) Selective hydrogenation process; carried out in the presence of at least one selective hydrogenation catalyst in a reaction section that feeds the feed material and a hydrogen-containing gas stream, the temperature of which is 100 to 280°C, the hydrogen partial pressure is 1.0 to 10.0 absolute MPa, and the space velocity per hour is 0.3 to 10.0 h -1 This yields hydrogenated effluent; b) Hydrogenation process; carried out in a hydrogenation reaction section, the hydrogenation reaction section using at least one fixed-bed reactor, the fixed-bed reactor containing n catalyst beds, where n is an integer of 1 or more, and each catalyst bed containing at least one type of hydrogenation catalyst, at least the hydrogenated effluent obtained from step a) and a hydrogen-containing gas stream are supplied to the hydrogenation reaction section, the temperature when using the hydrogenation reaction section is 250 to 430°C, the partial pressure of hydrogen is 1.0 to 10.0 absolute MPa, and the space velocity per hour is 0.1 to 10.0 h -1 This yields hydrogenation treatment effluent; c) Hydrocracking step; carried out in a hydrocracking reaction section, the hydrocracking reaction section using at least one fixed-bed reactor, the fixed-bed reactor containing n catalyst beds, where n is an integer of 1 or more, and each catalyst bed containing at least one type of hydrocracking catalyst, at least the hydrogenation effluent obtained from step b) and a hydrogen-containing gas stream being supplied to the hydrocracking reaction section, the temperature when using the hydrocracking reaction section being 250 to 480°C, the partial pressure of hydrogen being 1.5 to 25.0 absolute MPa, and the space velocity per hour being 0.1 to 10.0 h -1 This yields hydrocracking-treated effluent; d) Separation step; the hydrocracking effluent obtained from step c) and an aqueous solution are fed, and the temperature during this step is 50 to 370°C, and at least one type of gaseous effluent, an aqueous effluent, and a hydrocarbon-based effluent are obtained.

[0014] One advantage of the method according to the present invention is that the oil obtained from the thermal decomposition of plastic waste is purified from at least some of its impurities, thereby making it possible to hydrogenate it and thus upgrade it, in particular by directly incorporating it into a fuel pool, or by making it suitable for processing in a steam decomposition unit, so that light olefins, which can function as monomers in the production of polymers, can be obtained in high yield.

[0015] Another advantage of the present invention is that it avoids the risk of clogging and / or corrosion of the processing unit in which the method of the present invention is carried out. This risk is exacerbated by the presence of often large amounts of diolefins, metals, and halogenated compounds in the plastic pyrolysis oil.

[0016] The method of the present invention makes it possible to obtain hydrocarbon-based effluent from plastic pyrolysis oil. The obtained effluent is at least partially free of impurities from the starting plastic pyrolysis oil, thereby limiting operability issues, such as corrosion, coking, or catalyst deactivation. These impurities can be particularly problematic in the steam decomposition unit and / or units located downstream of the steam decomposition unit, especially the polymerization unit and selective hydrogenation unit. By removing at least some of the impurities from the oil obtained from the pyrolysis of plastic waste, it is also possible to broaden the range of applications of the target polymer and reduce application incompatibility.

[0017] The present invention participates in plastic recycling by proposing a method for processing and refining oil obtained from the pyrolysis of plastics, hydrotreating and hydrocracking it to obtain a hydrocarbon-based effluent with reduced impurity content, which is therefore directly upgradeable in the form of naphtha and / or diesel fractions, or has a composition compatible with the feedstock of a steam cracking unit. Hydrocracking makes it possible to convert at least a portion of the heavy fraction (diesel) into compounds of the naphtha fraction, thereby making it possible to obtain an improved yield of the naphtha fraction, which, when sent to steam cracking, makes it possible to obtain an improved yield of light olefins, while at the same time reducing the risk of clogging during the processing steps of plastic pyrolysis oil, e.g., as described in the prior art, and the risk of large amounts of coke formation and / or corrosion encountered in subsequent steps (one or more), e.g., during the steam cracking of the plastic pyrolysis oil.

[0018] According to one variation, the method also includes step e) fractionating all or part of the hydrocarbon-based effluent obtained from step d) to obtain at least one gas stream and at least two liquid hydrocarbon-based streams, wherein the two liquid hydrocarbon-based streams are at least one naphtha fraction containing a compound with a boiling point of 175°C or less, and one hydrocarbon fraction containing a compound with a boiling point greater than 175°C.

[0019] According to one variation, the method also includes a recycling step f), in which at least a portion of the fraction obtained from the fractionation step e) containing compounds with a boiling point greater than 175°C is sent to a hydrocracking step c).

[0020] According to one variation, the method also includes a recycling step g), in which a portion of the hydrocarbon-based effluent obtained from the separation step d) or a portion of the naphtha fraction obtained from the fractionation step e) containing compounds with a boiling point of 175°C or less is sent to a selective hydrogenation step a) and / or a hydrogenation treatment step b).

[0021] According to one variation, the amount of recycled flow from process f) and / or g) is adjusted so that the weight ratio between the recycled flow and the feedstock containing plastic pyrolysis oil is 10 or less.

[0022] According to one variation, a stream containing an amine is injected upstream of step a).

[0023] According to one variation, the method includes a0) a step of pre-treating a feedstock containing plastic pyrolysis oil, the pre-treatment step being performed upstream of the selective hydrogenation step a), and including a filtration step and / or a washing step with water and / or an adsorption step.

[0024] According to one variation, the reaction section of step a) or b) uses at least two reactors that function in a variable-arrangement manner.

[0025] According to one variation, the selective hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional group comprising at least one group VIII element and at least one group VIB element, or at least one group VIII element.

[0026] According to one variation, the at least one hydrogenation catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional group comprising at least one group VIII element and / or at least one group VIB element.

[0027] According to one variation, the hydrocracking catalyst comprises a support selected from alumina halides, a combination of boron and aluminum oxides, amorphous silica-alumina and zeolites, and a hydrodehydrogenating functional group comprising at least one group VIB metal selected individually or as a mixture from chromium, molybdenum and tungsten, and / or at least one group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0028] According to this modification, the zeolite is selected from Y zeolite alone, or in combination with other zeolites from among beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48, and ZBM-30, either alone or in a mixture.

[0029] According to one variation, the hydrocarbon-based effluent obtained from separation step d), or at least one of the two liquid hydrocarbon-based flows obtained from any step e), is sent whole or partially to steam decomposition step h), which is carried out in at least one pyrolysis furnace at a temperature of 700-900°C and a pressure of 0.05-0.3 MPa (relative pressure).

[0030] According to one variation, the naphtha fraction obtained from step e) containing compounds with a boiling point of 175°C or less is fractionated into a heavy naphtha fraction containing compounds with a boiling point of 80 to 175°C and a light naphtha fraction containing compounds with a boiling point of less than 80°C, and at least a portion of the heavy fraction is sent to an aromatic complex including at least one naphtha reforming step.

[0031] According to this modification, at least a portion of the light naphtha fraction is sent to the steam cracking step h).

[0032] The present invention also relates to products that can be obtained through the processing method according to the present invention.

[0033] According to the present invention, pressure is absolute pressure (sometimes referred to as "abs.") and is expressed in units of MPa (absolute pressure) (or MPa abs.) unless otherwise specified.

[0034] According to the present invention, the expressions "comprised between ... and ..." and "between ... and ..." are equivalent, meaning that both limit values ​​of the interval are included within the range of values ​​stated. If this is not the case, and if both limit values ​​are not included within the range stated, this fact will be explicitly stated by the present invention.

[0035] For the purposes of the present invention, various ranges of parameters for a given process, such as pressure ranges and temperature ranges, may be used individually or in combination. For example, for the purposes of the present invention, a range of suitable pressure values ​​may be combined with a range of more suitable temperature values.

[0036] Specific and / or preferred embodiments of the present invention may be described below. They may be carried out separately or in combination, and there are no restrictions on the combination, as long as it is technically feasible.

[0037] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, Editor-in-Chief DR. Lide, 81st edition, 2000-2001). For example, Group VIII according to the CAS classification corresponds to the metals from columns 8, 9, and 10 of the new IUPAC classification.

[0038] The metal content is measured by X-ray fluorescence. [Modes for carrying out the invention]

[0039] (Detailed explanation) (Feed material) According to the present invention, “plastic pyrolysis oil” is an oil obtained from the pyrolysis of plastics, preferably plastic waste, particularly plastic waste resulting from collection and sorting channels, and advantageously, an oil in liquid form at room temperature. It particularly comprises hydrocarbon-based compounds, among others, paraffins, monoolefins and / or diolefins, naphthenes and aromatic compounds, these hydrocarbon-based compounds preferably have a boiling point of less than 700°C, preferably less than 550°C. The plastic pyrolysis oil may contain, and usually contains, impurities, such as metals, particularly silicon and iron, and halogenated compounds, particularly chlorinated compounds. These impurities may be present in the plastic pyrolysis oil at high concentrations, for example, up to 350 ppm by weight, even more than 700 ppm by weight, even more than 1000 ppm by weight, in terms of halogen elements provided by halogenated compounds, and up to 100 ppm by weight, even more than 200 ppm by weight, in terms of metallic or semimetallic elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals, and metalloids may be likened to metallic contaminants called metals or metallic or semimetallic elements. In particular, metals or metallic or semimetallic elements that may be contained in oils obtained from the pyrolysis of plastic waste include silicon, iron, or both of these elements. Plastic pyrolysis oil may also contain other impurities, such as heteroatoms, particularly provided by sulfur compounds, oxygen compounds, and / or nitrogen compounds, in concentrations generally less than 10,000 ppm by weight, preferably less than 4,000 ppm by weight, of heteroatoms.

[0040] The feedstock of the method according to the present invention comprises at least one type of plastic pyrolysis oil. The feedstock may consist only of one or more types of plastic pyrolysis oil. Preferably, the feedstock comprises at least 50% by weight, preferably 75% to 100% by weight of plastic pyrolysis oil, i.e., preferably 50% to 100% by weight, preferably 70% to 100% by weight of plastic pyrolysis oil. The feedstock of the method according to the present invention may, in particular, include one or more types of plastic pyrolysis oil, conventional petroleum-based feedstocks, or feedstocks obtained from biomass conversion, which are then co-treated with the plastic pyrolysis oil of the feedstock.

[0041] Plastic pyrolysis oils can be obtained from thermal catalytic pyrolysis treatment or, alternatively, prepared by hydrothermal decomposition (thermal decomposition in the presence of a catalyst and hydrogen).

[0042] (Pre-processing (optional)) The feed material containing plastic pyrolysis oil may, advantageously, be pretreated in an optional pretreatment step a0) prior to the selective hydrogenation step a) to obtain a pretreated feed material, which is then supplied to step a).

[0043] This optional pretreatment step a0) makes it possible to reduce the amount of contaminants, particularly silicon, that may be present in the feedstock containing plastic pyrolysis oil. Therefore, the optional pretreatment step a0) of the feedstock containing plastic pyrolysis oil is advantageous if the feedstock contains more than 50 ppm by weight of metallic elements, particularly more than 20 ppm by weight, more specifically more than 10 ppm by weight, and even more specifically more than 5 ppm by weight, in particular if the feedstock contains more than 20 ppm by weight of silicon, more specifically more than 10 ppm by weight, even more specifically more than 5 ppm by weight, and even more specifically more than 1.0 ppm of silicon.

[0044] The aforementioned optional pretreatment step a0) may be carried out by any method known to those skilled in the art for reducing the amount of contaminants. It may include, in particular, a filtration step and / or a washing step with water and / or an adsorption step.

[0045] According to one variation, the arbitrary pretreatment step a0) is carried out in the adsorption section in the presence of at least one adsorbent. The temperature during the arbitrary pretreatment step a0) is 0 to 150°C, preferably 5 to 100°C, and the pressure is 0.15 to 10.0 absolute MPa, preferably 0.2 to 1.0 absolute MPa. The adsorption section is advantageously operated in the presence of at least one adsorbent, preferably an alumina-type adsorbent, the specific surface area of ​​which is 100 m². 2 / g or more, preferably 200m 2 The specific surface area of ​​the at least one adsorbent is preferably 600 m². 2 / g or less, especially 400m 2 It is less than / g. 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 the standard ASTM D 3663-78, which was established from the Brunauer-Emmett-Teller method described in the periodical The Journal of the American Chemical Society, 60, 309 (1938).

[0046] Advantageously, the adsorbent contains less than 1% by weight of metallic elements, and preferably does not contain metallic elements. The term "metallic elements of the adsorbent" should be understood to refer to elements from groups 6-10 of the periodic table (new IUPAC classification).

[0047] The adsorption section of any step a0) includes at least one adsorption column, preferably at least two, and more preferably two to four, adsorption columns, which contain the adsorbent. If the adsorption section includes two adsorption columns, one mode of operation may be called a “swing” operation according to technical terms, in which one column is online, i.e., in service, while the other column is in reserve. When the adsorbent in the online column is used up, this column is separated, while the in-reserve column is brought online, i.e., in service. The used adsorbent can then be regenerated in situ and / or replaced with fresh adsorbent, and the column containing it can be brought online again where the other column has been separated.

[0048] Another operating configuration involves operating at least two columns in series. When the adsorbent in the column positioned at the head becomes depleted, this first column is separated, and the depleted adsorbent is either regenerated on-site or replaced with fresh adsorbent. The columns are then brought back online at their final position. This operating configuration is known as a variable-arrange configuration, or as a permutable reactor system (PRS), or in specialized terminology, "lead and lag." The combination of at least two adsorption columns makes it possible to overcome the potential for rapid poisoning and / or clogging of the adsorbent due to the combined action of metallic contaminants, diolefins, gum-like substances derived from diolefins, and insoluble substances that may be present in the pyrolysis oil of the plastic being treated. The reason for this is that the presence of at least two adsorption columns facilitates the replacement and / or regeneration of the adsorbent, advantageously without stopping the pretreatment unit, or even the method itself, thus reducing the risk of clogging, thus avoiding unit shutdowns due to clogging, controlling costs, and limiting adsorbent consumption.

[0049] The optional pretreatment step a0) may optionally involve feeding, advantageously, at least a portion of the recycled flow obtained from step h) of the Method, either as a mixture with the feedstock containing plastic pyrolysis oil or separately.

[0050] Therefore, the aforementioned optional pretreatment step a0) makes it possible to obtain pretreated feedstock, which is then supplied to the selective hydrogenation step a).

[0051] (Selective hydrogenation process a)) According to the present invention, the method comprises a step a) of selective hydrogenation of a feedstock containing plastic pyrolysis oil, which is carried out in an amount of soluble hydrogen just necessary for the selective hydrogenation of diolefins present in the plastic pyrolysis oil, under hydrogen pressure and temperature conditions that allow the feedstock to remain in the liquid phase in the presence of hydrogen. Selective hydrogenation of diolefins in the liquid phase makes it possible to avoid or at least limit the formation of a “gummy substance” that could clog the reaction section of hydrogenation step b), i.e., polymerization of diolefins, and therefore the formation of oligomers and polymers. The selective hydrogenation step a) makes it possible to obtain a hydrogenated effluent, i.e., an effluent with a reduced olefin, particularly diolefin, content, preferably a diolefin-free effluent.

[0052] According to the present invention, the selective hydrogenation step a) is carried out in a reaction section, which is fed at least with the feedstock containing plastic pyrolysis oil or the pretreated feedstock obtained from any pretreatment step a0), and a gas stream containing hydrogen (H2). In some cases, the reaction section of step a) may advantageously be fed directly to at least one inlet of the reactor in the reaction section of step a) with at least a part of the recycle stream, preferably the recycle stream obtained from step d) or any step h), as a mixture with the feedstock, optionally the pretreated feedstock, or separately from the feedstock, optionally the pretreated feedstock. By introducing at least a part of the recycle stream into the reaction section of the selective hydrogenation step a), it is possible to advantageously dilute the impurities in the feedstock, optionally the pretreated feedstock, and control the temperature, particularly the temperature in the reaction section.

[0053] The reaction section includes selective hydrogenation, preferably in a fixed bed, in the presence of at least one selective hydrogenation catalyst, the temperature at that time is advantageously 100 to 280 °C, preferably 120 to 260 °C, preferably 130 to 250 °C, the partial pressure of hydrogen is 1.0 to 10.0 absolute MPa, preferably 1.5 to 8.0 absolute MPa, and the hourly space velocity (HSV) at that time is 0.3 to 10.0 h -1 , preferably 0.5 to 5.0 h -1 . The hourly space velocity (HSV) is here defined as the ratio of the hourly volume flow rate of the feedstock containing plastic pyrolysis oil, optionally the pretreated feedstock, to the volume of the catalyst (one or more). The amount of the gas stream containing hydrogen (H2) fed to the reaction section of step a) is advantageously such that the hydrogen coverage is 1 to 200 Nm of hydrogen per cubic meter of the feedstock volume (m 3 ), preferably 1 to 50 Nm of hydrogen per cubic meter of the feedstock volume (m 3 (Nm 3 / m 3 ), preferably per cubic meter of the feedstock volume (m 3 ) 1 to 50 Nm of hydrogen 3 (Nm3 / m 3 ), preferably the volume of the supplied raw material (m³ 3 ) Hydrogen per unit: 5-20 Nm 3 (Nm 3 / m 3 The hydrogen coating rate is defined as the ratio at 15°C of the volumetric flow rate of hydrogen taken in under standard temperature and pressure conditions to the volumetric flow rate of the “fresh” feedstock, i.e., the volumetric flow rate of the feedstock to be processed without taking into account any portion to be recycled, and in some cases the volumetric flow rate of the feedstock that has been pre-treated (volume of feedstock (m³) 3 ) Nm of H2 per unit 3 Standard m described as 3 The hydrogen-containing gas stream supplied to the reaction section of step a) may consist of feed hydrogen and / or recycled hydrogen specifically obtained from separation step d).

[0054] Advantageously, the reaction section of step a) comprises 1 to 5 reactors. According to certain embodiments of the present invention, the reaction section comprises 2 to 5 reactors, which operate in a permutable reactor system as referred to by the term PRS or the term "read-and-drag". Combining at least two reactors in a PRS configuration makes it possible to separate one reactor, discharge the spent catalyst, refill the reactor with fresh catalyst, and return the reactor to an operational state without stopping the method. PRS technology is described in particular in patent FR2681871.

[0055] Advantageously, reactor inserts, such as filter plate types, may be used to prevent clogging of the reactor(s). An example of a filter plate is described in Patent FR3051375.

[0056] Advantageously, the at least one selective hydrogenation catalyst comprises a support, preferably a mineral support, and a hydrogenation dehydrogenation functional group.

[0057] According to one variation, the hydrogenation-dehydrogenation functional group comprises, in particular, at least one group VIII element and at least one group VIB element, wherein the group VIII element is preferably selected from nickel and cobalt, and the group VIB element is preferably selected from molybdenum and tungsten. According to this variation, the total content of metallic element oxides from group VIB and group VIII is preferably 1% to 40% by weight, and preferably 5% to 30% by weight, relative to the total weight of the catalyst. The weight ratio expressed as metal oxides between the group VIB metals (one or more) and the group VIII metals (one or more) is preferably 1 to 20, and preferably 2 to 10.

[0058] According to this modification, the reaction section of step a) includes, for example, a selective hydrogenation catalyst, which comprises 0.5% to 12% by weight of nickel, preferably 1% to 10% by weight of nickel (expressed as nickel oxide NiO relative to the weight of the catalyst), and 1% to 30% by weight of molybdenum, preferably 3% to 20% by weight of molybdenum (expressed as molybdenum oxide MoO3 relative to the weight of the catalyst), on a support, preferably a mineral support, preferably an alumina support.

[0059] According to another modification, the hydrogenation-dehydrogenation functional group comprises, and preferably consists of, at least one group VIII element, preferably nickel. According to this modification, the nickel oxide content is preferably 1% to 50% by weight, and preferably 10% to 30% by weight, relative to the weight of the catalyst. This type of catalyst is preferably used in its reduced form on a support, preferably a mineral support, and preferably an alumina support.

[0060] The support for the at least one selective hydrogenation catalyst is preferably selected from alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof. The support may contain other dopant compounds, in particular boron oxides, especially oxides selected from boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide, and mixtures thereof. Preferably, the at least one selective hydrogenation catalyst comprises an alumina support and is optionally 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 alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. If boron trioxide (B2O5) is present, its concentration is less than 10% by weight relative to the weight of alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. The alumina used may be, for example, gamma (γ) or eta (η) alumina.

[0061] The selective hydrogenation catalyst is, for example, in the form of an extruded product.

[0062] Much more preferably, in order to hydrogenate the diolefin as selectively as possible, step a) may use, in addition to the selective hydrogenation catalyst described above, at least one selective hydrogenation catalyst used in step a), which contains 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, on an alumina support. This catalyst packed with a small amount of metal is preferably placed upstream of the selective hydrogenation catalyst described above.

[0063] In some cases, the feedstock containing plastic pyrolysis oil may be optionally pre-treated and / or optionally pre-mixed with a recycled flow, preferably at least a portion of the recycled flow obtained from step d) or any step g), which may be mixed with a gas flow containing hydrogen before its introduction into the reaction section.

[0064] The feed material is optionally pre-treated and / or optionally mixed with at least a portion of a recycled flow, preferably from process d) or any process g), and / or, optionally, as a mixture with a gas flow, and before being introduced into the reaction section of process a), this feed material may be heated, for example, by heat exchange, in particular with the hydrogenation effluent from process b), to reach a temperature close to the operating temperature in the reaction section to which it is supplied.

[0065] The content of impurities, particularly diolefins, in the hydrogenated effluent obtained at the end of step a) is reduced relative to the content of the same impurities, particularly diolefins, contained in the feedstock for this method. The selective hydrogenation step a) generally makes it possible to convert at least 90%, preferably at least 99%, of the diolefins contained in the initial feedstock. Step a) also makes it possible to remove other contaminants, such as silicon, at least partially. The hydrogenated effluent obtained as a result of the selective hydrogenation step a) is preferably sent directly to the hydrogenation step b). If at least a portion of the recycled flow obtained from any step g) is introduced, the hydrogenated effluent obtained as a result of the selective hydrogenation step a) therefore includes the converted feedstock plus the portion(s) of the recycled flow.

[0066] (Hydrogenation process b)) According to the present invention, the treatment method includes step b) to hydrogenate the hydrogenated effluent obtained from step a) as a mixture with a recycled flow, preferably at least a portion of a recycled flow obtained from step d) or any step f) and / or g) in the presence of hydrogen and at least one hydrogenation catalyst, preferably in a fixed bed, to obtain a hydrogenated effluent.

[0067] Advantageously, step b) includes hydrogenation reactions well known to those skilled in the art, particularly hydrogenation reactions of olefins or aromatic compounds, such as hydrogenation, demetallation, hydrogenation, desulfurization, and denitrification.

[0068] Advantageously, step b) is carried out in a hydrogenation reaction section, which includes at least one, preferably 1 to 5, fixed-bed reactors. Each fixed-bed reactor contains n catalyst beds, where n is an integer of 1 or more, preferably 1 to 10, and preferably 2 to 5. Each of the beds(s) contains at least one, and preferably 10 or fewer, hydrogenation catalysts. If the reactor contains several catalyst beds, i.e., at least two, preferably 2 to 10, and preferably 2 to 5 catalyst beds, the catalyst beds are arranged in series within the reactor.

[0069] The hydrogenation reaction section is advantageous in that it supplies the hydrogenated effluent obtained from step a) and the hydrogen-containing gas stream to at least the first catalyst bed of the first functioning reactor.

[0070] The hydrogenation reaction section of step b) may be fed with a recycle flow, preferably at least a portion of the recycle flow obtained from step d) or any steps f) and / or g). The portion(s) or the entirety of the recycle flow may be introduced into the hydrogenation reaction section as a mixture with the hydrogenated effluent obtained from step a) or separately. The portion(s) or the entirety of the recycle flow may be introduced into the hydrogenation reaction section into one or more catalyst beds of the hydrogenation reaction section of step b). The introduction of at least a portion of the recycle flow may, advantageously, dilute impurities still present in the hydrogenated effluent and control the temperature in the catalyst bed(s) of the hydrogenation reaction section, which involves a highly exothermic reaction, in particular limiting the temperature rise.

[0071] Advantageously, the hydrogenation reaction section is carried out at a pressure equivalent to that used in the reaction section of selective hydrogenation step a), but at a higher temperature than the reaction section of selective hydrogenation step a). Therefore, the hydrogenation temperature when the hydrogenation reaction section is advantageously carried out is 250 to 430°C, preferably 280 to 380°C, the partial pressure of hydrogen at which point is 1.0 to 10.0 absolute MPa, and the space velocity per hour (HSV) at which point is 0.1 to 10.0 h. -1 Preferably 0.1 to 5.0 hours -1 Prioritizing 0.2-2.0h -1 Preferably 0.2 to 0.8 hours -1 Therefore, according to the present invention, the "hydrogenation temperature" corresponds to the average temperature in the hydrogenation reaction section of step b). In particular, it corresponds to the weight-average bed temperature (WABT) according to the terminology well known to those skilled in the art. The hydrogenation temperature is advantageously determined according to the catalyst system, equipment and its configuration used. For example, the hydrogenation temperature (i.e., WABT) is calculated by the following method:

[0072]

number

[0073] In the formula, T inlet : Temperature of the hydrogenated effluent at the entrance of the hydrogenation reaction section, T outlet This is the temperature of the effluent at the outlet of the hydrogenation reaction section.

[0074] The space velocity per hour (HSV) is defined here as the ratio of the hourly volumetric flow rate of the hydrogenated effluent obtained from step a) to the volume of catalyst(s)(1 or more). The hydrogen coating in step b) is advantageously determined by the volume (m³) of the fresh feed material supplied to step a). 3 ) Hydrogen content: 50-1000 Nm 3 Preferably, the volume (m³) of fresh raw material to be supplied to step a) 3 ) Hydrogen 50-500 Nm 3 Preferably, the volume (m³) of fresh raw material to be supplied to step a) 3 ) Hydrogen per unit: 100-300 Nm 3 The hydrogen coverage is defined here as the ratio of the volumetric flow rate of hydrogen taken under standard temperature and pressure conditions to the volumetric flow rate of fresh feed material supplied to process a), i.e., feed material containing plastic pyrolysis oil, or optionally pre-treated feed material supplied to process a), to the volumetric flow rate of hydrogen (volume of fresh feed material (m³). 3 ) Nm of H2 per unit 3 Standard m 3 ). The hydrogen may consist of recycled hydrogen specifically obtained from the supply and / or separation step d).

[0075] Preferably, an additional gas flow containing hydrogen is advantageously introduced to the inlet of each reactor, particularly reactors operating in series, and / or to the inlet of each catalyst bed from the second catalyst bed of the hydrogenation reaction section. These additional gas flows are also called cooling flows. They allow for temperature control in the hydrogenation reactor, where the reactions involved are generally highly exothermic.

[0076] Advantageously, the hydrogenation catalyst used in step b) may be selected from known demetallation, hydrogenation, or silicon capture catalysts, particularly those used for the treatment of petroleum fractions, and combinations thereof. Known demetallation catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 5221656, US 5827421, US 7119045, US 5622616, and US 5089463. Known hydrogenation catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 6589908, US 4818743, or US 6332976. Known silicon capture catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0077] In particular, the hydrogenation catalyst comprises a support, preferably a mineral support, and at least one metal element having a hydrogenation-dehydrogenation function. The metal element having a hydrogenation-dehydrogenation function preferably comprises at least one group VIII element (preferably selected from the group consisting of nickel and cobalt), and / or at least one group VIB element (preferably selected from the group consisting of molybdenum and tungsten). The total content of oxides of metal elements from group VIB and group VIII is preferably 0.1% to 40% by weight, and preferably 5% to 35% by weight, relative to the total weight of the catalyst. The weight ratio of group VIB metals (single or multiple) to group VIII metals (single or multiple), expressed as metal oxides, is preferably 1.0 to 20, and preferably 2.0 to 10. For example, the hydrogenation reaction section of step b) of the method includes a hydrogenation catalyst comprising 0.5% to 10% by weight of nickel, preferably 1% to 8% by weight of nickel (expressed as nickel oxide NiO relative to the total weight of the hydrogenation catalyst) and 1.0% to 30% by weight of molybdenum, preferably 3.0% to 29% by weight of molybdenum (expressed as molybdenum oxide MoO3 relative to the total weight of the hydrogenation catalyst), on a mineral support.

[0078] In particular, the hydrogenation catalyst comprises a support, preferably a mineral support, and at least one metallic element having a hydrogenation-dehydrogenation function. The metallic element having a hydrogenation-dehydrogenation function preferably comprises at least one group VIII element, preferably a group VIII element selected from the group consisting of nickel and cobalt, and / or at least one group VIB element, preferably a group VIB element selected from the group consisting of molybdenum and tungsten. The total content of oxides of metallic elements from group VIB and group VIII is preferably 0.1% to 40% by weight, and preferably 5% to 35% by weight, relative to the total weight of the catalyst. The weight ratio expressed as metal oxides between group VIB metals (one or more) and group VIII metals (one or more) is preferably 1.0 to 20, and preferably 2.0 to 10. For example, the hydrogenation catalyst included in the hydrogenation reaction section of step b) of this method contains, on a mineral support, 0.5% to 10% by weight of nickel, preferably 1% to 8% by weight, expressed as nickel oxide NiO relative to the total weight of the hydrogenation catalyst, and 1.0% to 30% by weight of molybdenum, preferably 3.0% to 29% by weight, expressed as molybdenum oxide MoO3 relative to the total weight of the hydrogenation catalyst.

[0079] The support for the hydrogenation catalyst is preferably selected from alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof. The support may also contain other dopant compounds, particularly boron oxides, especially boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide, and mixtures thereof. Preferably, the hydrogenation 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 alumina, and preferably at least 0.001% by weight relative to the total weight of alumina. If boron trioxide (B2O5) is present, its concentration is less than 10% by weight relative to the weight of alumina, and preferably at least 0.001% by weight relative to the total weight of alumina. The alumina used may be, for example, γ (gamma) or η (eta) alumina.

[0080] The hydrogenation catalyst is, for example, in the form of an extruded product.

[0081] Advantageously, the specific surface area of ​​the hydrogenation catalyst used in step b) of this method is 250 m². 2 / g or more, preferably 300m 2 It is 1 / g or more. The specific surface area of ​​the hydrogenation treatment catalyst is preferably 800 m². 2 Less than or equal to / g, preferably 600m 2 / g or less, especially 400m 2 The specific surface area of ​​the hydrogenation catalyst is measured by the BET method. That is, the specific surface area is determined by nitrogen adsorption according to the standard ASTM D 3663-78, which was established from the Brunauer-Emmett-Teller method described in the periodical The Journal of the American Chemical Society, 60, 309 (1938). Such a specific surface area makes it possible to further improve the removal of contaminants, especially metals, such as silicon.

[0082] According to another aspect of the present invention, the hydrogenation catalyst also includes one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to as “additivated catalysts.” Generally, the organic compounds are selected from compounds containing one or more chemical functional groups selected from functional groups of carboxylic acids, alcohols, thiols, thioethers, sulfones, sulfoxides, ethers, aldehydes, ketones, esters, carbonates, amines, nitriles, imides, oximes, ureas, and amides, or compounds containing furan rings, or sugars.

[0083] Hydrogenation step b) advantageously allows for optimized treatment of the hydrogenated effluent obtained from step a). This makes it possible to maximize the hydrogenation of unsaturated bonds of olefinic compounds present in the hydrogenated effluent obtained from step a), the demetallation of the hydrogenated effluent, and the capture of metals still present in the hydrogenated effluent, particularly silicon. Hydrogenation step b) also enables hydrodenitrification (HDN) of the hydrogenated effluent, i.e., the conversion of nitrogen species still present in the hydrogenated effluent. Preferably, the nitrogen content of the hydrogenated effluent obtained from step b) is 10 ppm by weight or less.

[0084] In a preferred embodiment of the present invention, the hydrogenation reaction section comprises several fixed-bed reactors, preferably 2 to 5, more preferably 2 to 4, each containing n catalyst beds, where n is an integer of 1 or more, preferably 1 to 10, preferably 2 to 5, and advantageously operated in series and / or parallel and / or variable array (or PRS) mode and / or "swing" mode. Various arbitrary operating modes, PRS (or read-and-drag) mode and swing mode are well known to those skilled in the art and are advantageously as defined below. The advantage of a hydrogenation reaction section comprising several reactors lies in the optimized treatment of the hydrogenated effluent while simultaneously reducing the risk of clogging of one or more catalyst beds, and thus making it possible to avoid unit shutdowns due to clogging.

[0085] According to a highly preferred embodiment of the present invention, the hydrogenation reaction section includes, preferably, the following: -(b1) Two fixed-bed reactors operating in a swing or array-variable manner, preferably in a PRS manner; each of the two reactors preferably has a catalyst bed, which advantageously contains a hydrogenation catalyst, which is preferably selected from known hydrogenation demetallation or silicon capture catalysts and combinations thereof; and -(b2) At least one fixed-bed reactor, preferably one reactor; located downstream of reactor (b1), and advantageously operating in series with reactor (b1), the fixed-bed reactor (b2) contains 1 to 5 catalyst beds arranged in series, each containing 1 to 10 hydrogenation catalysts, at least one of the hydrogenation catalysts advantageously containing a support and at least one metallic element, the metallic element preferably containing at least one group VIII element and / or at least one group VIB element, the group VIII element preferably selected from nickel and cobalt, and the group VIB element preferably selected from molybdenum and tungsten.

[0086] In some cases, step b) may include a heating section. This heating section is located downstream of the hydrogenation reaction section, and in this heating section, the hydrogenated effluent obtained from step a) is heated to a temperature suitable for hydrogenation, i.e., 250-430°C. The optional heating section may therefore include one or more exchangers, preferably exchangers that allow heat exchange between the hydrogenated effluent and the hydrogenated effluent, and / or a preheating furnace.

[0087] Advantageously, the hydrogenation process b) allows for the complete hydrogenation of olefins present in the initial feedstock and those that may be obtained after the selective hydrogenation process a), while also allowing for at least partial conversion of other impurities present in the feedstock, such as aromatic compounds, metallic compounds, sulfur compounds, nitrogen compounds, halogen compounds (especially chlorine compounds), and oxygen compounds. Process b) also allows for a further reduction in the content of contaminants, such as the content of metals, particularly silicon.

[0088] (Hydrocrack process c)) According to the present invention, the treatment method includes a first step c) in which the hydrocracking effluent obtained from step b) is optionally mixed with a recycling flow, preferably a portion of the recycling flow obtained from step d) or any step f) and / or g), and hydrocracking it in the presence of hydrogen and at least one hydrocracking catalyst, preferably in a fixed bed, to obtain a hydrocracking effluent.

[0089] Advantageously, step c) includes a hydrocracking reaction well known to those skilled in the art, which in particular enables the conversion of heavy compounds contained in the hydrogenated effluent obtained from step b), such as compounds with boiling points greater than 175°C, to compounds with boiling points 175°C or less. Other reactions, such as hydrogenation, hydrodemetallation, hydrodesulfurization, and hydrodenitrification of olefins or aromatic compounds, may follow.

[0090] Advantageously, step c) is carried out in a hydrocracking section, which includes at least one, preferably 1 to 5, fixed-bed reactors. Each fixed-bed reactor contains n catalyst beds, where n is 1 or more, preferably 1 to 10, and preferably an integer from 2 to 5. Each of the beds(s) contains at least one, and preferably 10 or fewer, hydrocracking catalysts. If the reactor contains several catalyst beds, i.e., at least two, preferably 2 to 10, and preferably 2 to 5 catalyst beds, the catalyst beds are arranged in series within the reactor.

[0091] The hydrogenation process b) and the hydrocracking process c) may, advantageously, be carried out in the same reactor or in different reactors. If they are carried out in the same reactor, the reactor includes several catalyst beds, the first catalyst bed containing one or more hydrogenation catalysts, and the subsequent catalyst beds containing one or more hydrocracking catalysts.

[0092] The hydrocracking reaction section is advantageous in that it supplies the hydrogenated effluent obtained from step b) and the hydrogen-containing gas stream to at least the first catalyst bed of the first functioning reactor.

[0093] The hydrocracking reaction section of step c) may be fed with a recycle flow, preferably at least a portion of the recycle flow obtained from step d) or any step f) and / or g). The portion(s) or the entirety of the recycle flow may be introduced into the hydrocracking reaction section as a mixture with the hydrogenated effluent obtained from step b), or separately. The portion(s) or the entirety of the recycle flow may be introduced into the hydrocracking reaction section, into one or more catalyst beds of the hydrocracking reaction section of step c). Introducing at least a portion of the recycle flow may, advantageously, dilute impurities still present in the hydrogenated effluent and allow for temperature control, in particular, limiting the temperature rise, in the catalyst bed(s) of the hydrocracking reaction section, which involves a highly exothermic reaction.

[0094] Advantageously, the hydrocracking reaction section is carried out at a pressure equivalent to that used in the reaction section of the selective hydrogenation step a) or the hydrogenation treatment step b).

[0095] Therefore, the hydrogenation temperature when the hydrogenocrack reaction section is carried out is advantageously 250 to 480°C, preferably 320 to 450°C, the partial pressure of hydrogen at that time is 1.5 to 25.0 absolute MPa, preferably 2 to 20 absolute MPa, and the space velocity per hour (HSV) at that time is 0.1 to 10.0 h -1 Preferably 0.1 to 5.0 hours -1 Prioritizing 0.2-4 hours -1 Therefore, according to the present invention, the "hydrocracking temperature" corresponds to the average temperature in the hydrocracking reaction section of step c). In particular, it corresponds to the weight-average bed temperature (WABT) according to the terminology well known to those skilled in the art. The hydrocracking temperature is advantageously determined according to the catalyst system, equipment and configuration used. For example, the hydrocracking temperature (or WABT) is calculated by the following method:

[0096]

number

[0097] In the formula, T inlet : Temperature of the hydrogenated effluent at the entrance of the hydrogenocrack reaction section, T outlet : The temperature of the effluent at the outlet of the hydrogenocrack reaction section.

[0098] Space velocity per hour (HSV) is defined here as the ratio of the hourly volume flow rate of the hydrogenated effluent obtained from step a) per volume of catalyst(s)(one or more). The hydrogen coating in step c) is advantageously determined by the volume (m³) of the fresh feed material supplied to step a). 3 ) Hydrogen content: 80-2000 Nm 3 Preferably, the volume (m³) of fresh raw material to be supplied to step a) 3 ) Hydrogen content: 200-1800 Nm 3 The hydrogen coverage is defined here as the ratio of the volumetric flow rate of hydrogen utilized under standard temperature and pressure conditions to the volumetric flow rate of the fresh feed material supplied to process a), i.e., the feed material containing plastic pyrolysis oil, or optionally pre-treated feed material supplied to process a), (volume of fresh feed material (m³) 3 ) Nm of H2 per unit 3 Standard m, which is expressed as 3 ). The hydrogen may consist of supply hydrogen and / or recycled hydrogen specifically obtained from separation step d).

[0099] Preferably, an additional gas flow containing hydrogen is advantageously introduced to the inlet of each reactor, particularly to reactors operating in series, and / or to the inlet of each catalyst bed from the second catalyst bed in the hydrocracking reaction section. These additional gas flows are also called cooling flows. They also allow for temperature control in the hydrocracking reactor, where the reactions involved are generally highly exothermic.

[0100] In an embodiment that enables the maximization of the production of a naphtha fraction containing compounds with a boiling point of 175°C or lower, the operating conditions used in the hydrocracking step c) generally allow for a conversion rate of more than 15% by weight, more preferably 20% to 95% by weight, per pass of feed material entering the hydrocracking step c), to a product having a volume of at least 80% of the product having a boiling point of 175°C or lower, preferably less than 160°C, and preferably less than 150°C.

[0101] Hydrocracking step c) does not necessarily enable the conversion of all compounds with boiling points above 175°C to compounds with boiling points below 175°C. After fractionation step e), a greater or lesser proportion of compounds with boiling points above 175°C may remain. To increase the conversion rate, at least a portion of this unconverted fraction may be recycled to step f) as described below. Another portion may be purged as described below.

[0102] According to the present invention, step c) is carried out in the presence of at least one hydrocracking catalyst.

[0103] The hydrocracking catalyst (one or more types) used in step c) is a conventional hydrocracking catalyst known to those skilled in the art, and is a dual-function type combining an acidic functional group with a hydrogenation-dehydrogenating functional group and, optionally, at least one binder matrix. The acidic function has a high surface acidity (generally 150-800 m). 2 The hydrogenation and dehydrogenation function is provided by a carrier having a surface area ( / g), such as halogenated (especially chlorinated or fluorinated) alumina, a combination of boron and aluminum oxides, amorphous silica-alumina, and zeolites.

[0104] Preferably, the hydrocracking catalyst(s) used in step c) include a hydrodehydrogenating functional group. The hydrodehydrogenating functional group includes at least one metal from Group VIII, and the at least one metal from Group VIII is selected from iron, cobalt, nickel, ruthenium, rhodium, palladium, and platinum, preferably from cobalt and nickel. Preferably, the catalyst(s) also include at least one metal from Group VIB. The at least one metal from Group VIB is selected from chromium, molybdenum, and tungsten, either alone or in a mixture, preferably from molybdenum and tungsten. NiMo, NiMoW, or NiW type hydrodehydrogenating functional groups are preferred.

[0105] Preferably, the content of metals from Group VIII in the hydrocracking catalyst (one or more types) is advantageously 0.5% to 15% by weight, preferably 1% to 10% by weight, and the percentage is expressed as the weight percentage of oxides relative to the total weight of the catalyst.

[0106] Preferably, the content of metals from Group VIB in the hydrocracking catalyst (one or more types) is advantageously 5% to 35% by weight, preferably 10% to 30% by weight, and the percentage is expressed as the weight percentage of oxides relative to the total weight of the catalyst.

[0107] The hydrocracking catalyst (one or more types) used in step c) may optionally contain at least one promoter element, which is deposited on the catalyst and selected from the group formed by phosphorus, boron, and silicon, and may optionally contain at least one element from group VIIA (preferably chlorine and fluorine), may optionally contain at least one element from group VIIB (preferably manganese), and may optionally contain at least one element from group VB (preferably niobium).

[0108] Preferably, the hydrocracking catalyst(s) used in step c) comprises at least one amorphous or poorly crystallized porous mineral matrix of oxide type, selected individually or in mixtures from alumina, silica, silica-alumina, aluminate, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide, or clay, and preferably selected individually or in mixtures from alumina or silica-alumina.

[0109] Preferably, the silica-alumina contains more than 50% by weight of alumina, preferably more than 60% by weight of alumina.

[0110] Preferably, the hydrocracking catalyst(s) used in step c) may also include a zeolite, which is selected from Y zeolite, preferably USY zeolite, either alone or in combination with other zeolites from among beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48, or ZBM-30, either alone or in a mixture. Preferably, the zeolite is a single USY zeolite.

[0111] When the catalyst contains zeolite, the zeolite content in the hydrocracking catalyst (one or more types) is advantageously 0.1% to 80% by weight, preferably 3% to 70% by weight, and the percentage is expressed as the percentage of zeolite relative to the total weight of the catalyst.

[0112] A suitable catalyst comprises, and preferably consists of, at least one metal from Group VIB and optionally at least one non-precious metal from Group VIII, at least one promoter element, preferably phosphorus, at least one Y zeolite, and at least one alumina binder.

[0113] Even more preferred catalysts include, and preferably consist of, nickel, molybdenum, phosphorus, USY zeolite, and optionally beta-olite, and alumina.

[0114] Other preferred catalysts include, and preferably consist of, nickel, tungsten, alumina, and silica-alumina.

[0115] Other suitable catalysts include, and preferably consist of, nickel, tungsten, USY zeolite, alumina, and silica-alumina.

[0116] The hydrogenocrack catalyst is, for example, in the form of an extruded product.

[0117] According to another aspect of the present invention, the above-described hydrocracking catalyst also includes one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to as “additive catalysts.” Generally, the organic compounds are selected from compounds containing one or more chemical functional groups selected from functional groups of carboxylic acids, alcohols, thiols, thioethers, sulfones, sulfoxides, ethers, aldehydes, ketones, esters, carbonates, amines, nitriles, imides, oximes, ureas, and amides, or compounds containing furan rings, or sugars.

[0118] The preparation of catalysts for steps a), b), or c) is known and generally involves impregnation onto a support with a group VIII metal and, if present, a group VIB metal, and optionally phosphorus and / or boron, followed by drying, and optionally calcination. In the case of additive catalysts, the preparation is generally carried out by simple drying without calcination after the introduction of the organic compound. The term “calcination” here means a heat treatment at a temperature of 200°C or higher under air or an oxygen-containing gas. Prior to their use in the process, the catalysts are generally subjected to sulfidation to form active species. The catalyst for step a) may be a catalyst used in its reduced form, and therefore its preparation includes a reduction step.

[0119] In some cases, step c) may include a heating section. This heating section is located downstream of the hydrocracking reaction section and heats the hydrogenated effluent obtained from step b) to a temperature suitable for hydrocracking, i.e., 250–480°C. The optional heating section may therefore include one or more exchangers, preferably exchangers that allow heat exchange between the hydrogenated effluent and the hydrocracking effluent, and / or a preheating furnace.

[0120] (Separation step d)) According to the present invention, the processing method includes a separation step d), which is advantageously carried out in at least one washing / separation section, which is fed at least one aqueous solution with the hydrocracking effluent obtained from step c), to obtain at least one gaseous effluent, an aqueous effluent, and a hydrocarbon-based effluent.

[0121] The gaseous effluent obtained as a result of step d) preferably contains hydrogen, preferably at least 90% by volume, and more preferably at least 95% by volume. Advantageously, the gaseous effluent may be recycled, at least in part, to selective hydrogenation steps a) and / or hydrogenation steps b) and / or hydrocracking steps c) and f), the recycling system optionally including a purification section.

[0122] The aqueous effluent obtained as a result of step d) preferably contains an ammonium salt and / or hydrochloric acid.

[0123] The hydrocarbon-based effluent obtained from step d) contains hydrocarbon-based compounds and, advantageously, corresponds to plastic pyrolysis oil of the feedstock, or conventional biomass co-treated with plastic pyrolysis oil and a fraction or pyrolysis oil of a conventional petroleum-based feedstock, in which at least a portion of the heavy compounds are converted to lighter compounds, maximizing the naphtha fraction. The hydrocarbon-based effluent is also, at least in part, free of impurities, particularly its olefinic (diolefinic and monoolefinic) impurities, metallic impurities, and halogenated impurities.

[0124] This separation step d) makes it possible to remove, in particular, chloride ions released by the hydrogenation of chlorinated compounds, especially those in the form of HCl formed during dissolution in water following step b), and ammonium chloride salts formed by the reaction between ammonium ions dissolved in water on top of those produced during step b) and / or provided by the injection of amines, thus limiting the risk of clogging due to the precipitation of ammonium chloride salts, in particular in the transfer line and / or the section of the method of the present invention and / or the transfer line to the steam cracker. This also makes it possible to remove hydrochloric acid formed by the reaction of hydrogen ions and chloride ions.

[0125] Depending on the content of chlorinated compounds in the initial feedstock to be processed, a stream containing amines, such as monoethanolamine, diethanolamine, and / or monodiethanolamine, may be injected upstream of selective hydrogenation step a), between selective hydrogenation step a) and hydrogenation step b), and / or between hydrocracking step c) and separation step d), preferably upstream of selective hydrogenation step a), to ensure a sufficient amount of ammonium ions to bind with the chloride ions formed during the hydrogenation step, thus limiting the formation of hydrochloric acid and thus limiting corrosion downstream of the separation section.

[0126] Advantageously, separation step d) includes the injection of an aqueous solution, preferably water, into the hydrocracking effluent obtained from step c) upstream of the washing / separation section to at least partially dissolve the ammonium chloride salt and / or hydrochloric acid, thus improving the removal of chlorinated impurities and reducing the risk of clogging caused by the accumulation of ammonium chloride salt.

[0127] The temperature during separation step d) is advantageously 50 to 370°C, preferredly 100 to 340°C, and preferably 200 to 300°C. Advantageously, separation step d) is carried out at a pressure close to that used in steps a) and / or b) and / or c), preferably 1.0 to 10.0 MPa, to facilitate hydrogen recycling.

[0128] The washing / separation section of step d) may be carried out in at least part in common or separate washing and separation equipment, which is well known (separation vessels, pumps, heat exchangers, washing columns, etc., which may be operated at various pressures and temperatures).

[0129] In any embodiment of the present invention, in addition to or apart from other embodiments described of the present invention, separation step d) comprises injecting an aqueous solution into the hydrocracking effluent obtained from step c), followed by a washing / separation section, which advantageously includes a separation phase for obtaining at least one aqueous effluent packed with ammonium salts, a washed liquid hydrocarbon-based effluent, and a partially washed gaseous effluent. The aqueous effluent packed with ammonium salts and the washed liquid hydrocarbon-based effluent may subsequently be separated in a decantation vessel to obtain the hydrocarbon-based effluent and the aqueous effluent. The partially washed gaseous effluent may, in parallel, be introduced into a washing column, where it flows countercurrently against an aqueous flow, preferably an aqueous flow of the same nature as the aqueous solution injected into the hydrocracking effluent, which removes at least partially, preferably completely, the hydrochloric acid contained in the partially washed gaseous effluent, thus enabling the obtaining the gaseous effluent, preferably the gaseous effluent essentially containing hydrogen, and an acidic aqueous flow. The aqueous effluent obtained from the decanting container may optionally be mixed with the acidic water stream, and may optionally be used as a mixture with the acidic water stream in the water recycling circuit and fed to step d) separation to the aqueous solution and / or the water stream in the washing column upstream of the washing / separation section. The water recycling circuit may include supplying water and / or a basic solution and / or purging to remove dissolved salts.

[0130] In another optional embodiment of the present invention, either separately from or in combination with other embodiments described therein, separation step d) may advantageously include a “high pressure” washing / separation section, which operates at a pressure close to that of selective hydrogenation step a) and / or hydrogenation treatment step b) and / or hydrocracking step c) to facilitate hydrogen recycling. This optional “high pressure” section of step d) may be completed in a “low pressure” section to obtain a hydrocarbon-based liquid fraction that does not contain a gaseous portion dissolved at high pressure and is intended to be treated directly in a steam cracking method or optionally sent to fractionation step e).

[0131] The gas fraction(s) obtained from separation step d) may undergo additional purification(one or more) and separation(one or more) for the purpose of recovering at least one hydrogen-rich gas and / or light hydrocarbons, particularly ethane, propane, and butane; the hydrogen-rich gas may be recycled upstream to steps a) and / or b) and / or c); and the light hydrocarbons may be sent, advantageously, separately or in mixture, to one or more furnaces of steam cracking step h) to increase the overall yield of olefins.

[0132] The hydrocarbon-based effluent obtained from separation step d) is sent, partially or entirely, directly to the inlet of the steam cracking unit or to any of the fractionation steps e). Preferably, the hydrocarbon-based liquid effluent is sent, partially or entirely, preferably entirely, to fractionation step e).

[0133] (Fractional step e) (Optional) The method according to the present invention may include a step of fractionating all or part, preferably all, of the hydrocarbon-based effluent obtained from step d) to obtain at least one gas stream and at least two liquid hydrocarbon-based streams, the two liquid hydrocarbon-based streams comprising at least one naphtha fraction containing a compound having a boiling point of 175°C or less, particularly 80 to 175°C, and at least one hydrocarbon fraction containing a compound having a boiling point greater than 175°C.

[0134] Step e) makes it particularly possible to remove gases dissolved in the hydrocarbon-based liquid spill, such as ammonia, hydrogen sulfide, and light hydrocarbons containing 1 to 4 carbon atoms.

[0135] The pressure during any fractionation step e) is advantageously 1.0 absolute MPa or less, preferably 0.1 to 1.0 absolute MPa.

[0136] According to one embodiment, step e) may be carried out in a section that advantageously includes at least one stripping column having a reflux circuit including a reflux vessel. The stripping column is fed with the hydrocarbon-based liquid effluent obtained from step d) and a water vapor stream. The hydrocarbon-based liquid effluent obtained from step d) may optionally be heated before entering the stripping column. Thus, the lightest compounds are encombined at the top of the column and carried to a reflux circuit containing a reflux vessel where gas / liquid separation takes place. The gas phase containing the light hydrocarbons is withdrawn from the reflux vessel as a gas stream. The naphtha fraction containing compounds with boiling points below 175°C is advantageously withdrawn from the reflux vessel. The hydrocarbon fraction containing compounds with boiling points above 175°C is advantageously withdrawn at the bottom of the stripping column.

[0137] In other embodiments, fractionation step e) may include only a stripping column and the subsequent distillation column or distillation column.

[0138] Naphtha fractions containing compounds with a boiling point of 175°C or less and fractions containing compounds with a boiling point greater than 175°C may, optionally, be mixed and sent whole or partially to a steam cracking unit at the outlet of the steam cracking unit. The olefins may be (re)formed to participate in polymer formation. Preferably, only a portion of the fraction is sent to the steam cracking unit; at least a portion of the remainder may, optionally, be sent to a fuel pool, e.g., a naphtha pool, a diesel pool, or a kerosene pool, obtained from a recycling process f) or g) and / or from conventional petroleum-based feedstock.

[0139] According to a preferred embodiment, the naphtha fraction containing compounds with a boiling point of 175°C or less is sent whole or partially to a steam decomposition unit, and the fraction containing compounds with a boiling point greater than 175°C is sent to a recycling process f) and / or a fuel pool.

[0140] In certain embodiments, optional fractionation step e) may allow obtaining, in addition to the gas stream, a naphtha fraction containing compounds with a boiling point of 175°C or less, preferably 80 to 175°C; an intermediate distillate fraction containing compounds with a boiling point greater than 175°C and less than 385°C; and a hydrocarbon fraction known as a heavy hydrocarbon fraction, containing compounds with a boiling point of 385°C or more. The naphtha fraction may be sent, in whole or in part, to a steam cracking unit and / or a naphtha pool obtained from a conventional petroleum-based feedstock; it may be sent to a recycling step g); the diesel fraction may be sent, in whole or in part, to either a steam cracking unit or a diesel pool obtained from a conventional petroleum-based feedstock, or to a recycling step f); the heavy fraction may, in part, be sent to a steam cracking unit or to a recycling step f).

[0141] In another specific embodiment, optional fractionation step e) may allow obtaining, in addition to the gas stream, a naphtha fraction containing compounds with a boiling point of 175°C or less, preferably 80 to 175°C; a kerosene fraction containing compounds with a boiling point greater than 175°C and less than 280°C; a diesel fraction containing compounds with a boiling point greater than 280°C and less than 385°C; and a hydrocarbon fraction known as a heavy hydrocarbon fraction, containing compounds with a boiling point of 385°C or more. The naphtha fraction may be sent, in whole or in part, to a steam cracking unit and / or a naphtha pool obtained from a conventional petroleum-based feedstock; it may be sent to recycling step g); the kerosene or diesel fraction may be sent, in whole or in part, to either a steam cracking unit or a kerosene or diesel pool obtained from a conventional petroleum-based feedstock, respectively, or to recycling step f); the heavy fraction may, in part, be sent to a hydrocracking unit or to recycling step f).

[0142] In another specific embodiment, the naphtha fraction obtained from step e) containing compounds with a boiling point of 175°C or less is fractionated into a heavy naphtha fraction containing compounds with a boiling point of 80 to 175°C and a light naphtha fraction containing compounds with a boiling point of less than 80°C, and at least a portion of the heavy naphtha fraction is sent to an aromatic complex which includes at least one naphtha reforming step aimed at producing aromatic compounds. According to this embodiment, at least a portion of the light naphtha fraction is sent to the steam cracking step h) described below.

[0143] The gas fractions(s) obtained from fractionation step e) may be subjected to additional purification(s) and separation(s)(s)(s) for the purpose of recovering at least light hydrocarbons, particularly ethane, propane, and butane, and the light hydrocarbons may be advantageously sent separately or in mixture to one of the furnaces of steam cracking step h) to increase the overall yield of olefins.

[0144] (Recycling process f for fractions containing compounds with a boiling point above 175°C) (Optional) The method according to the present invention may include a recycling step f), in which at least a portion of the fraction obtained from the fractionation step e) containing compounds with a boiling point greater than 175°C is recovered to form a recycling stream, which is sent upstream to, or directly to, at least one of the reaction steps of the method according to the present invention, in particular, a selective hydrogenation step a) and / or a hydrogenation treatment step b) and / or a hydrocracking step c). In some cases, a portion of the recycling stream may be sent to any step a0).

[0145] The recycled flow may be supplied to reaction steps a) and / or b) and / or c) in a single injection, or it may be divided into several parts and supplied to reaction steps a) and / or b) and / or c) in multiple injections, i.e., it may be supplied in separate portions to different catalyst beds.

[0146] Advantageously, the amount of the recycled flow of fractions containing compounds with a boiling point above 75°C is adjusted such that the weight ratio of the recycled flow to the feedstock containing plastic pyrolysis oil, i.e., the feedstock to be processed and fed to the whole method, is 10 or less, preferably 5 or less, and more preferably 0.001 or more, preferably 0.01 or more, and preferably 0.1 or more. Much more preferably, the amount of the recycled flow is adjusted such that the weight ratio of the recycled flow to the feedstock containing plastic pyrolysis oil is 0.2 to 5.

[0147] Preferably, the method according to the present invention includes a recycling step f). More preferably, at least a portion of the fraction containing compounds with a boiling point greater than 175°C obtained from the fractionation step e) is sent to a hydrocracking step c). By recycling a portion of the fraction containing compounds with a boiling point greater than 175°C to at least one of the reaction steps of the method according to the present invention, particularly the hydrocracking step c), or upstream thereof, it is advantageously possible to increase the yield of the naphtha fraction with a boiling point less than 175°C. Recycling also makes it possible to dilute impurities and to control the temperature in the reaction step(s) involved, which may be highly exothermic.

[0148] A purge may be provided when recycling the fraction containing compounds with a boiling point above 175°C. Depending on the operating conditions of the method, the purge may be 0 to 10% by weight, preferably 0.5% to 5% by weight, of the fraction containing compounds with a boiling point above 175°C relative to the incoming feedstock.

[0149] (Step g) (optional) Recycling of hydrocarbon-based effluent obtained from (step d) and / or naphtha fraction with a boiling point of 175°C or less obtained from step e). The method according to the present invention may include a recycling step g), in which a portion of the hydrocarbon-based effluent obtained from the separation step d) or a portion of the naphtha fraction with a boiling point of 175°C or less obtained from an optional fractionation step e) is recovered to form a recycling flow. The recycling flow is sent upstream of or directly to at least one of the reaction steps of the method according to the present invention, in particular to a selective hydrogenation step a) and / or a hydrogenation treatment step b). In some cases, a portion of the recycling flow may be sent to an optional pretreatment step a0). Preferably, the method according to the present invention includes a recycling step g).

[0150] Preferably, at least a portion of the hydrocarbon-based effluent obtained from separation step d) or the naphtha fraction with a boiling point of 175°C or less obtained from any fractionation step e) is fed to hydrogenation step b).

[0151] Advantageously, the amount of recycled flow, i.e., the proportion of recycled obtained products, is adjusted so that the weight ratio of the recycled flow to the feedstock containing plastic pyrolysis oil, i.e., the feedstock to be processed and fed to the whole method, is 10 or less, preferably 5 or less, and more preferably 0.001 or more, preferably 0.01 or more, and preferably 0.1 or more. Much more preferably, the amount of recycled flow is adjusted so that the weight ratio of the recycled flow to the feedstock containing plastic pyrolysis oil is 0.2 to 5.

[0152] Advantageously, in the initial stages of this method, an external hydrocarbon fraction may be used as the recycling flow. Those skilled in the art will know how to select such hydrocarbon fraction.

[0153] By recycling a portion of the obtained product to at least one of the reaction steps of the method according to the present invention, it is advantageous to first dilute impurities and second to control the temperature during the reaction step(s) in which the reactions involved may be highly exothermic.

[0154] According to a preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps: a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, and e) fractionation, which produce an effluent, at least a portion of which is suitable for processing in a steam cracking unit.

[0155] According to another preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps including, preferably consisting of, a0) pretreatment, a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, and e) to produce an effluent, at least a portion of which can be processed in a steam decomposition unit.

[0156] According to a third preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps: a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, e) fractionation, and f) recycling a fraction containing compounds having a boiling point greater than 175°C during steps a) and / or b), which produce effluent, or at least a portion thereof, which can be processed in a steam decomposition unit.

[0157] According to a fourth preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps: a0) pretreatment, a) selective hydrogenation, b) hydrotreatment, c) hydrocracking, d) separation, e) fractionation, and f) recycling of a fraction containing compounds having a boiling point greater than 175°C, which produce effluent, at least a portion of which can be processed in a steam decomposition unit.

[0158] According to a fifth preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps: a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, e) fractionation, f) recycling fractions containing compounds with a boiling point greater than 175°C, and g) recycling fractions containing compounds with a boiling point less than or equal to 175°C, which produce effluent, at least a portion of which can be processed in a steam decomposition unit.

[0159] According to a sixth preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, a series of steps: a0) pretreatment, a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, e) fractionation, f) recycling fractions containing compounds with a boiling point greater than 175°C, and g) recycling fractions containing compounds with a boiling point less than or equal to 175°C, which produce effluent, at least a portion of which can be processed in a steam decomposition unit.

[0160] According to a seventh very preferred embodiment of the present invention, a method for processing a feedstock containing plastic pyrolysis oil is a series of steps, preferably comprising, and preferably comprising, in a given order: a0) pretreatment, a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, e) fractionation, f) recycling a fraction containing compounds with a boiling point greater than 175°C back to step c), and g) recycling a fraction containing compounds with a boiling point 175°C or less back to steps a) and / or b), which produce effluent, at least a portion of which can be processed in a steam decomposition unit.

[0161] The hydrocarbon-based effluent or hydrocarbon-based stream(s) thus obtained by processing plastic pyrolysis oil according to the method of the present invention has a composition that can conform to the specifications of the feedstock entering the steam decomposition unit. In particular, the composition of the hydrocarbon-based effluent or hydrocarbon-based stream(s) is preferably as follows: - The total content of metallic elements is 5.0 ppm by weight or less, preferably 2.0 ppm by weight or less, more preferably 1.0 ppm by weight or less, and more preferably 0.5 ppm by weight or less, and accordingly: - The silicon (Si) content is 1.0 ppm by weight or less, preferably 0.6 ppm by weight or less. - The iron (Fe) content is 100 ppb by weight or less. - The sulfur content is 500 ppm by weight or less, preferably 200 ppm by weight or less. - The nitrogen content is 100 ppm by weight or less, preferably 50 ppm by weight or less, preferably 5 ppm by weight or less. - The asphaltene content is less than 5.0 ppm by weight. - The total content of chlorine element is 10 ppm by weight or less, preferably 1.0 ppm by weight or less. - The content of olefin compounds (monoolefins and diolefins) is 5.0% by weight or less, preferably 2.0% by weight or less, and preferably 0.1% by weight or less.

[0162] The content is given as relative weight concentration relative to the total weight of the flow under consideration, as a percentage by weight (%), parts per million by weight (ppm), or parts per ten billion by weight (ppb).

[0163] The method according to the present invention therefore makes it possible to treat plastic pyrolysis oil to obtain an effluent that can be injected whole or partially into a steam decomposition unit.

[0164] (Steam decomposition process h) (Optional) The hydrocarbon-based effluent obtained from separation step d), or at least one of the two liquid hydrocarbon-based flows obtained from any step e), may be sent whole or partially to steam crackling step h).

[0165] Advantageously, the gas fractions(s) obtained from separation step d) and / or fractionation step e) containing ethane, propane, and butane may be sent whole or partially to steam cracking step h).

[0166] The steam decomposition step h) is preferably carried out in at least one pyrolysis furnace at a temperature of 700 to 900°C, preferably 750 to 850°C, and under a pressure of 0.05 to 0.3 relative MPa. The residence time of the hydrocarbon-based compound is generally 1.0 second (denoted as s) or less, preferably 0.1 to 0.5 s. Steam is preferably introduced upstream of any steam decomposition step h) after separation (or fractionation). The amount of water introduced, preferably in the form of steam, is preferably 0.3 to 3.0 kg of water per kg of the weight (kg) of the hydrocarbon-based compound entering step h). Any step h) is preferably carried out in a plurality of parallel pyrolysis furnaces, with operating conditions adapted to various flows supplied to step h), in particular the flow obtained from step e), and further controlling the decoking time of the tubes. The furnaces include one or a plurality of tubes arranged in parallel. The furnaces may also represent a group of furnaces operating in parallel. For example, the furnace may be dedicated to the decomposition of naphtha fractions containing compounds with a boiling point of 175°C or lower.

[0167] Fluids from various steam cracking furnaces are generally recombined before separation to form a single flue. It is understood that the steam cracking step (h) includes not only the steam cracking furnace but also sub-steps related to steam cracking that are well known to those skilled in the art. These sub-steps may include, among other things, heat exchangers, columns and catalytic reactors and recycling to the furnace. Columns generally allow for the fractionation of the flue for the purpose of recovering at least one light fraction containing hydrogen and compounds containing 2 to 5 carbon atoms, a fraction containing pyrolysis gasoline, and optionally a fraction containing pyrolysis oil. Columns also allow for the separation of various components of the fractionated light fraction to recover at least one ethylene-rich fraction (C2 fraction), a propylene-rich fraction (C3 fraction), and optionally a butene-rich fraction (C4 fraction). Catalytic reactors particularly allow for the selective hydrogenation of the C2, C3, and even C4 fractions and pyrolysis gasoline. Saturated compounds, particularly those containing 2 to 4 carbon atoms, are advantageously recycled into steam cracking furnaces, improving the overall yield of olefins.

[0168] This steam decomposition step h) 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, particularly 30% by weight or more, especially 40% by weight or more, and even 50% by weight or more, of the total weight of olefins containing 2, 3, and 4 carbon atoms relative to the weight of the steam decomposition effluent under consideration. The C2, C3, and C4 olefins may, advantageously, be used as polyolefin monomers.

[0169] According to one or more preferred embodiments of the present invention, a method for processing a feedstock containing plastic pyrolysis oil, individually or in combination, comprises, and preferably comprises, the above-described series of steps, namely: a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, and h) steam cracking, preferably in a given order.

[0170] According to a preferred embodiment, a method for processing a feedstock containing plastic pyrolysis oil comprises, preferably in a given order, the above-described series of steps: a0) pretreatment, a) selective hydrogenation, b) hydrogenation treatment, c) hydrocracking, d) separation, e) fractionation, f) recycling a fraction containing compounds with a boiling point greater than 175°C back to step c), g) recycling a naphtha fraction containing compounds with a boiling point 175°C or less back to steps a) and / or b), and h) steam cracking.

[0171] The method according to the present invention, if it includes this steam decomposition step h), therefore makes it possible to obtain olefins from plastic pyrolysis oil, for example plastic waste, which can function as monomers for the synthesis of new polymers contained in plastics, in a relatively satisfactory yield, without clogging or corrosion of the unit.

[0172] (Analysis methods used) Analytical methods and / or standards used to determine the characteristics of various flows, particularly the characteristics of the feedstock and effluent to be processed, are known to those skilled in the art. These are listed below in particular.

[0173] [Table 1]

[0174] (List of drawings) Information regarding the elements referenced in Figures 1-4 will allow for a better understanding of the present invention, but the invention is not limited to the specific embodiments shown in Figures 1-4. The various embodiments presented may be used individually or in combination with each other, and there are no restrictions on the combinations.

[0175] Figure 1 shows a scheme of a specific embodiment of the method of the present invention, and includes the following: - Step a) of selective hydrogenation of a hydrocarbon-based feedstock obtained from the thermal decomposition of plastic (1): carried out in at least one fixed-bed reactor containing at least one selective hydrogenation catalyst in the presence of a hydrogen-rich gas (2) and any amine supplied by a flow (3) to obtain effluent (4); - Step b) Hydrogenation treatment of the effluent (4) obtained from step a); carried out in at least one fixed-bed reactor containing at least one hydrogenation catalyst in the presence of hydrogen (5) to obtain hydrogenated effluent (6); - The first step c) of hydrocracking the effluent (6) obtained from step c) is carried out in the presence of hydrogen (7) in at least one fixed-bed reactor containing at least one hydrocracking catalyst to obtain the first hydrocracking effluent (8); - Step d of separating the spill (8) is carried out in the presence of an aqueous washing solution (9) to obtain at least one fraction (10) containing hydrogen, an aqueous fraction (11) containing a dissolved salt, and a hydrocarbon-based liquid fraction (12).

[0176] Instead of injecting the amine stream (3) into the inlet of selective hydrogenation step a), it is possible to inject it into the inlet of hydrogenation step b), the inlet of hydrocracking step c), the inlet of separation step d), or not to inject it at all, depending on the characteristics of the feedstock.

[0177] Figure 2 shows another specific embodiment of the method according to the present invention. In the embodiment shown in Figure 2, the hydrocarbon-based liquid fraction (12) obtained at the end of step d) is sent to fractionation step e) which makes it possible to obtain at least one gas fraction (13), a naphtha fraction (14) containing a compound with a boiling point of 175°C or less, and a fraction (15) containing a compound with a boiling point greater than 175°C. At the end of step e), the naphtha fraction (14) containing the compound with a boiling point of 175°C or less is sent to a steam crackling method (not shown).

[0178] Figure 3 shows another specific embodiment of the method according to the present invention. In the embodiment shown in Figure 3, a portion (15a) of the fraction (15) obtained from step e) containing compounds with a boiling point of 175°C or higher constitutes a recycle flow and is fed to step c). Another portion (15b) constitutes a purge.

[0179] Figure 4 shows another specific embodiment of the method according to the present invention. In the embodiment shown in Figure 4, a portion of the naphtha fraction (14) obtained from step e) containing a compound with a boiling point of 175°C or less constitutes a recycled flow (fraction 14a)) fed to the selective hydrogenation step a) and a recycled flow (fraction 14b)) fed to the hydrogenation treatment step b).

[0180] To better understand the present invention, only the main steps are shown in Figures 1-4 along with the main flow. It is clearly understood that all equipment necessary for the function (vessels, pumps, exchangers, furnaces, columns, etc.) is present, even if not shown. It is also understood that the hydrogen-rich gas flow (supply or recycle) may be injected into 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 purifying and recycling hydrogen may be used.

[0181] (Examples) (Example 1: Conforms to the present invention) The raw material (1) processed in this method is plastic pyrolysis oil (i.e., containing 100% by weight of the aforementioned plastic pyrolysis oil) and has the characteristics shown in Table 2.

[0182] [Table 2]

[0183] (1) The MAV method is described in the following article: 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, pages 57-68 The raw material (1) is subjected to a selective hydrogenation process. This process is carried out in a fixed-bed reactor under the conditions shown in Table 3, in the presence of hydrogen (2) and an alumina-supported NiMo type selective hydrogenation catalyst.

[0184] [Table 3]

[0185] At the end of selective hydrogenation step a), all of the diolefins initially present in the feedstock were converted.

[0186] The effluent (4) obtained from the selective hydrogenation step a) is directly subjected to the hydrogenation step b) without separation. This step is carried out in a fixed bed under the conditions shown in Table 4, in the presence of hydrogen (5) and an alumina-supported NiMo type hydrogenation catalyst.

[0187] [Table 4]

[0188] The effluent (6) obtained from hydrogenation step b) is directly subjected to hydrocracking step c) without separation. This step is carried out in a fixed bed under the conditions shown in Table 5, in the presence of a zeolite hydrocracking catalyst containing hydrogen (7) and NiMo.

[0189] [Table 5]

[0190] The effluent (8) obtained from hydrocracking step c) is subjected to separation step d) according to the present invention, in which a stream of water (9) is injected into the effluent obtained from hydrocracking step c); the mixture is then sent to separation step d) and treated in a column for washing the acidic gas. A gas fraction (10) is obtained at the top of the acidic gas washing column, and at the bottom, the aqueous phase and liquid phase can be separated by a two-phase separation vessel. The gas washing column and the two-phase separator are operated under high pressure. The liquid phase is then sent to a low-pressure vessel to recover a second gas fraction and liquid effluent. This second gas fraction is purged. The yields for the various products and fractions obtained at the outlet of hydrocracking step c) are shown in Table 6 (the yield corresponds to the ratio of the mass of the various products obtained to the mass of the feed material upstream of step a), expressed as a percentage, and written as %m / m).

[0191] [Table 6]

[0192] Table 7 shows the characteristics of the PI+ fraction obtained after separation step d) (which corresponds to the liquid effluent (12)).

[0193] [Table 7]

[0194] Liquid fraction PI+ has a composition that makes it compatible with the water vapor decomposition unit for the following reasons: - Contains no olefins (monoolefins and diolefins) whatsoever; - Contains no chlorine whatsoever (the chlorine content was undetectable and below the limit required for steam decomposition feedstock); - Contains no iron (Fe) or metals whatsoever (metal content was undetectable and below the limit required for steam decomposition feedstock, i.e., ≤5.0 ppm by weight for metals, very preferably ≤1 ppm by weight; ≤100 ppb by weight for Fe); - Finally, it contains only small amounts of sulfur (<2 ppm by weight) and nitrogen (<0.8 ppm by weight), and these concentrations are significantly lower than the limits required for steam decomposition feedstocks (≤500 ppm by weight, preferably ≤200 ppm by weight, for S and N).

[0195] The PI+ fraction obtained through a series of steps, particularly step c) hydrocracking, consists of approximately 86% naphtha-type compounds with a boiling point of 175°C or lower. This high yield of naphtha-type compounds with a boiling point of 175°C or lower is achieved under hydrocracking conditions.

[0196] The liquid effluent PI+ is sent directly to the steam decomposition process h) under the conditions described in Table 8.

[0197] [Table 8]

[0198] The effluent from the steam cracking furnace is subjected to a separation process. This process allows for the recycling of saturated compounds back into the steam cracking furnace and produces the yields shown in Table 9 (yield = mass % of the product relative to the mass of PI + fraction upstream of the steam cracking process, expressed as %m / m).

[0199] [Table 9]

[0200] Considering the yield obtained for the PI+ fraction in the pyrolysis oil treatment method (see Table 6), it is possible to determine the total yield of the product obtained from the steam decomposition process relative to the initial feed material of the plastic pyrolysis oil type introduced in step a).

[0201] [Table 10]

[0202] When liquid fraction PI+ is subjected to a steam decomposition process, the method according to the present invention makes it possible to achieve total mass yields of ethylene and propylene of 31.6% and 17.2%, respectively, relative to the mass of the initial feedstock of the plastic pyrolysis oil type.

[0203] Furthermore, a specific series of steps upstream of the steam decomposition process makes it possible to limit coke formation and avoid corrosion problems that would arise if chlorine were not removed.

[0204] (Example 2 (Conforms to the present invention)) In this embodiment, the raw material to be processed is the same as that described in Example 1 (see Table 2).

[0205] The process involves steps a) of selective hydrogenation, b) of hydrogenation treatment, c) of hydrocracking, and d) of separation. These steps are carried out under the same conditions as described in Example 1. The liquid effluent obtained at the end of separation step d) is sent to fractionation step e), which includes a stripping column and a distillation column. The purpose of this is to obtain a fraction with a boiling point of 175°C or less (PI-175°C fraction) and a fraction with a boiling point greater than 175°C (175°C+ fraction).

[0206] Table 11 shows the total yields for the various fractions obtained at the end of separation step d) and fractionation step e) (this step includes stripping and distillation columns).

[0207] [Table 11]

[0208] The process of the present invention, particularly the treatment of the feedstock by step c) hydrocracking, makes it possible to obtain a very high yield of naphtha-type PI-175°C fraction.

[0209] Table 12 shows the characteristics of the liquid fractions PI-175°C and 175°C+ obtained after separation step d) and fractionation step e).

[0210] [Table 12]

[0211] Both liquid fractions PI-175℃ and 175℃+ have compositions that are compatible with the steam decomposition unit for the following reasons: - They contain no olefins (monoolefins and diolefins) whatsoever; - They have very low concentrations of elemental chlorine (undetectable and 25 wt ppb, respectively), which is below the limit required for steam cracking feedstock; - The metal content, particularly iron (Fe), is also very low (metal content is undetectable for the PI-175°C fraction and <1 ppm by weight for the 175°C+ fraction; Fe content is undetectable for the PI-175°C fraction and 25 ppb by weight for the 175°C+ fraction), and these are below the limits required for steam decomposition feedstock (≤5.0 ppm by weight for metal, very preferably ≤1 ppm by weight; ≤100 ppb by weight for Fe). - Finally, they contain sulfur (<2 ppm by weight for the PI-175°C fraction and <2 ppm by weight for the 175°C+ fraction) and nitrogen (<0.5 ppm by weight for the PI-175°C fraction and <3 ppm by weight for the 175°C+ fraction), with concentrations far lower than the limits required for steam decomposition feedstocks (≤500 ppm by weight for S and N, preferably ≤200 ppm by weight).

[0212] The liquid fractions PI-175°C and 175°C+ obtained in this manner are then sent to a steam decomposition step h), where the liquid fractions are decomposed under various conditions (see Table 13).

[0213] [Table 13]

[0214] The effluents from various steam cracking furnaces are subjected to a separation process. This separation process enables the recycling of saturated compounds back into the steam cracking furnaces and the generation of yields shown in Table 14 (yield = mass % of the product relative to the mass of each upstream fraction in the steam cracking process, expressed as %m / m).

[0215] [Table 14]

[0216] Considering the yields obtained at various liquid fractions PI-175°C and 175°C+ at the outlet of hydrocracking step c) in the pyrocracking oil treatment method (see Table 11), it is possible to determine the overall yield of the product obtained from the steam cracking step relative to the initial feedstock of the plastic pyrocracking oil type introduced into step a).

[0217] [Table 15]

[0218] When the PI-175°C and 175°C+ fractions are supplied separately to the steam decomposition unit, the method according to the present invention makes it possible to achieve overall mass yields of ethylene and propylene of 31.7% (=28.9 + 2.8) and 17.2% (=15.7 + 1.5), respectively, relative to the mass of the initial feedstock of the plastic pyrolysis oil type.

[0219] Furthermore, a specific arrangement of the upstream processes of the steam decomposition process makes it possible to limit coke formation and avoid corrosion problems that would arise if chlorine were not removed.

[0220] (Example 3 (Conforms to the present invention)) In this embodiment, the raw material to be processed is the same as that described in Example 1 (see Table 2).

[0221] It involves the steps of selective hydrogenation a), hydrogenation treatment b), hydrocracking c), and separation d). These steps are carried out under the same conditions as described in Example 1. The liquid effluent obtained at the end of separation step d) is sent to fractionation step e), which includes a stripping column and a distillation column. The purpose is to obtain the PI-175°C fraction and the 175°C+ fraction. The 175°C+ fraction is partially recycled upstream of hydrocracking step c) to improve the conversion rate of compounds with boiling points above 175°C. A small portion of the 175°C fraction is not recycled upstream of hydrocracking step c) (purged) to avoid the accumulation of polyaromatic compounds (which may be coke precursors).

[0222] The volumetric flow rate of the 175°C+ fraction obtained from fractionation step e) and recycled upstream of hydrocracking step c) is equal to half the volumetric flow rate of the liquid effluent obtained from hydrotreatment step b).

[0223] Table 16 shows the total yields for the various fractions obtained at the end of separation step c) and fractionation step d) (this step includes stripping and distillation columns).

[0224] [Table 16]

[0225] The process of the present invention, particularly the treatment of the feedstock by step c) hydrocracking, makes it possible to obtain a very high yield of naphtha-type PI-175°C fraction. This yield was even higher than that of Example 1. This is due to the recycling of the 175°C+ fraction, partially but substantially entirely, to the inlet of step c).

[0226] Table 17 shows the characteristics of the liquid fractions PI-175°C and 175°C+ obtained after separation step d) and fractionation step e).

[0227] [Table 17]

[0228] Both liquid fractions PI-175℃ and 175℃+ have compositions that are compatible with the steam decomposition unit for the following reasons: - They contain no olefins (monoolefins and diolefins) whatsoever; - They have very low concentrations of elemental chlorine (undetectable and 25 wt ppb, respectively), which is below the limit required for steam cracking feedstock; - The metal content, particularly iron (Fe), is also very low (metal content is undetectable for the PI-175°C fraction and <1 ppm by weight for the 175°C+ fraction; Fe content is undetectable for the PI-175°C fraction and 25 ppb by weight for the 175°C+ fraction), and these are below the limits required for steam decomposition feedstock (≤5.0 ppm by weight for metal, very preferably ≤1 ppm by weight; ≤100 ppb by weight for Fe). - Finally, they contain sulfur (<2 ppm by weight for the PI-175°C fraction and <2 ppm by weight for the 175°C+ fraction) and nitrogen (<0.5 ppm by weight for the PI-175°C fraction and <3 ppm by weight for the 175°C+ fraction), with concentrations far lower than the limits required for steam decomposition feedstocks (≤500 ppm by weight for S and N, preferably ≤200 ppm by weight).

[0229] In this Example 2, the 175°C+ fraction is purged from the unit and not sent to the steam decomposition process.

[0230] The resulting liquid fraction PI-175°C is then sent to the steam decomposition step h) (see Table 18).

[0231] [Table 18]

[0232] The effluents from various pyrolysis furnaces are subjected to a separation step. This step makes it possible to recycle the saturated compounds to the pyrolysis furnace and to achieve the yields shown in Table 19 (yield = mass % of the product relative to the mass of each of the fractions upstream of the pyrolysis step, denoted % m / m).

[0233] [Table 19]

[0234] In the hydrocracking process, considering the yields obtained for the liquid fraction at 175 °C+ at the outlet of the hydrocracking step (see Table 16), it is possible to determine the overall yield for the products obtained from the pyrolysis step i) relative to the initial feedstock of the plastic pyrolysis oil type introduced in step a).

[0235] [Table 20]

[0236] When the PI - 175 °C fraction is sent separately to the pyrolysis unit, the method according to the invention makes it possible to achieve overall mass yields of ethylene and propylene of 30.7% and 16.7% respectively relative to the mass of the initial feedstock of the plastic pyrolysis oil type.

[0237] Furthermore, a specific arrangement of the steps upstream of the pyrolysis step makes it possible to limit coke formation and to avoid corrosion problems that would occur if chlorine were not removed.

[0238] (Example 4 (not in accordance with the invention)) In this example, the feedstock to be treated is the same as that described in Example 1 (see Table 2).

[0239] This involves steps a) of selective hydrogenation, b) of hydrogenation treatment, and d) of separation, carried out under the same conditions as described in Example 1. In this example, which does not conform to the present invention, the effluent obtained from the hydrogenation treatment step is not subjected to the hydrocracking step. The liquid effluent obtained at the end of the separation step d) constitutes the PI+ fraction.

[0240] Table 21 shows the yields for the various products and fractions obtained at the outlet of hydrogenation process b) (the yields are expressed as a percentage, denoted as %m / m, corresponding to the ratio of the mass of the obtained products to the mass of the feedstock upstream of process a)).

[0241] [Table 21]

[0242] Table 22 shows the characteristics of the PI+ fraction (corresponding to the liquid effluent) obtained after separation step d).

[0243] [Table 22]

[0244] The PI+ fraction obtained through a series of steps a), b), and d) consists of approximately 35% naphtha-type compounds with a boiling point of 175°C or lower. This low yield of naphtha-type compounds with a boiling point of 175°C or lower is due to the absence of a hydrocracking step in this embodiment, which is not consistent with the present invention.

[0245] The liquid effluent fraction PI+ is directly sent to the steam decomposition step h) under the conditions described in Table 23.

[0246] [Table 23]

[0247] The effluent from the steam cracking furnace is subjected to a separation step, which makes it possible to recycle the saturated compounds to the steam cracking furnace and to achieve the yields shown in Table 24 (yield = mass % of the product relative to the mass of PI + fraction upstream of the steam cracking step, denoted as %m / m).

[0248]

Table 24

[0249] During the pyrolysis oil treatment process, considering the yields obtained for the PI + fraction at the outlet of the hydrotreatment step b) (see Table 21), it is possible to determine the total yield for the products obtained from the steam cracking step relative to the initial feedstock of the plastic pyrolysis oil type introduced in step a).

[0250]

Table 25

[0251] When the liquid fraction PI + is fed to the steam cracking step, by the method according to the invention, it is possible to achieve total mass yields of ethylene and propylene of 34.6% and 18.9% respectively relative to the mass of the initial feedstock of the plastic pyrolysis oil type.

[0252] When the liquid fraction PI + is fed to the steam cracking step, by the method according to the invention, it is possible to achieve total mass yields of ethylene and propylene of 34.6% and 18.9% respectively relative to the mass of the initial feedstock of the plastic pyrolysis oil type.

Brief Description of the Drawings

[0253] [Figure 1] Represents the scheme of a specific embodiment of the method of the present invention. [Figure 2] Represents another specific embodiment of the method according to the present invention. [Figure 3]Another specific embodiment of the method according to the present invention is shown. [Figure 4] Another specific embodiment of the method according to the present invention is shown.

Claims

1. A method for processing a feedstock containing plastic pyrolysis oil, comprising: a) A selective hydrogenation step for diolefins present in the plastic pyrolysis oil; carried out in the presence of at least one selective hydrogenation catalyst in a reaction section that supplies the feed material and a hydrogen-containing gas stream, the temperature being 100 to 280°C, the hydrogen partial pressure being 1.0 to 10.0 absolute MPa, and the space velocity being 0.3 to 10.0 h / hour. －１ This yields selectively hydrogenated effluent; b) Hydrogenation process; carried out in a hydrogenation reaction section, the hydrogenation reaction section using at least one fixed-bed reactor, the fixed-bed reactor containing n catalyst beds, where n is an integer of 1 or more, and each catalyst bed containing at least one type of hydrogenation catalyst, at least the selectively hydrogenated effluent obtained from step a) and a hydrogen-containing gas stream are supplied to the hydrogenation reaction section, the temperature when using the hydrogenation reaction section is 250 to 430°C, the partial pressure of hydrogen is 1.0 to 10.0 absolute MPa, and the space velocity per hour is 0.1 to 10.0 h －１ This yields hydrogenated effluent; c) Hydrocracking step; carried out in a hydrocracking reaction section, the hydrocracking reaction section using at least one fixed-bed reactor, the fixed-bed reactor containing n catalyst beds, where n is an integer of 1 or more, and each catalyst bed containing at least one type of hydrocracking catalyst, at least the hydrogenated effluent obtained from step b) and a hydrogen-containing gas stream being supplied to the hydrocracking reaction section, the temperature when using the hydrocracking reaction section being 250 to 480°C, the partial pressure of hydrogen being 1.5 to 25.0 absolute MPa, and the space velocity per hour being 0.1 to 10.0 h －１ This yields hydrocracking-treated effluent; d) Separation step; the hydrocracking effluent obtained from step c) and an aqueous solution are fed, the temperature during the step being 50 to 370°C; at least one gaseous effluent, an aqueous effluent, and a hydrocarbon-based effluent are obtained; step d) includes the injection of an aqueous solution into the hydrocracking effluent obtained from step c) upstream of the wash / separation section.

2. The method according to claim 1, further comprising step e) fractionating all or part of the hydrocarbon-based effluent obtained from step d) to obtain at least one gas stream and at least two liquid hydrocarbon-based streams, wherein the two liquid hydrocarbon-based streams are at least one naphtha fraction containing a compound having a boiling point of 175°C or less, and one hydrocarbon fraction containing a compound having a boiling point greater than 175°C.

3. The method according to claim 2, further comprising a recycling step f), wherein in step f), at least a portion of the fraction obtained from the fractionation step e) containing a compound with a boiling point greater than 175°C is sent to a hydrocracking step c).

4. The method according to any one of claims 1 to 3, further comprising a recycling step g), wherein in step g), a portion of the hydrocarbon-based effluent obtained from the separation step d) or a portion of the naphtha fraction containing a compound with a boiling point of 175°C or less obtained from the fractionation step e) is sent to a selective hydrogenation step a) and / or a hydrogenation treatment step b).

5. The method according to claim 3 or 4, wherein the amount of recycled flow from step f) and / or g) is adjusted such that the weight ratio between the recycled flow and the supply raw material containing plastic pyrolysis oil is 10 or less.

6. The method according to any one of claims 1 to 5, comprising a step a0) of pre-treating a supply material containing plastic pyrolysis oil, wherein the pre-treatment step is performed upstream of a) selective hydrogenation step, and further comprising a filtration step and / or a washing step with water and / or an adsorption step.

7. The method according to any one of claims 1 to 6, wherein the reaction section of step a) or b) uses at least two reactors that function in a variable arrangement.

8. The method according to any one of claims 1 to 7, wherein a stream containing an amine is injected upstream of step a).

9. The method according to any one of claims 1 to 8, wherein the selective hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional group comprising at least one group VIII element and at least one group VIB element, or at least one group VIII element.

10. The method according to any one of claims 1 to 9, wherein the at least one hydrogenation catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional group comprising at least one group VIII element and / or at least one group VIB element.

11. The method according to any one of claims 1 to 10, wherein the hydrocracking catalyst comprises a support selected from a combination of alumina halides, boron and aluminum oxides, amorphous silica-alumina and zeolites, and a hydrodehydrogenating functional group comprising at least one group VIB metal selected individually or as a mixture from chromium, molybdenum and tungsten, and / or at least one group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

12. The method according to claim 11, wherein the zeolite is selected from Y zeolite alone, or in combination with other zeolites from among beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 and ZBM-30, either alone or in a mixture.

13. The method according to any one of claims 1 to 12, wherein the hydrocarbon-based effluent obtained from separation step d), or at least one of two liquid hydrocarbon-based flows obtained from any step e), is sent whole or partially to a steam decomposition step h), and the steam decomposition step h) is carried out in at least one pyrolysis furnace, the temperature being 700 to 900°C and the pressure being 0.05 to 0.3 relative MPa.

14. The method according to claim 2 or 3, wherein the naphtha fraction obtained from step e) containing a compound with a boiling point of 175°C or less is fractionated into a heavy naphtha fraction containing a compound with a boiling point of 80 to 175°C and a light naphtha fraction containing a compound with a boiling point of less than 80°C, and at least a portion of the heavy naphtha fraction is sent to an aromatic complex including at least one naphtha reforming step.

15. The method according to claim 14, wherein at least a portion of the light naphtha fraction is sent to a steam cracking step h).

Images