Method for the purification of a plastic liquefaction oil composition in a turbulent flow, and use thereof

Abstract

Disclosed is a method for purifying a composition comprising a plastic liquefaction oil, the method comprising: a) providing a composition comprising a plastic liquefaction oil containing at least 20 ppm by weight of heteroatoms, b) bringing said composition in contact with an aqueous medium at a pH greater than 7, the contacting being carried out in a turbulent flow having a Reynolds number greater than 2000 and at a maximum temperature of 250° C to obtain an effluent containing the modified composition, c) subjecting the effluent of step (b) to (c1) washing in the presence of water or a solvent immiscible with the modified composition, (c2) separation, or to the succession of steps (c2) and (c1), and obtaining a purified composition having a reduced heteroatom content, and a phase containing the basic compound containing the basic compound and heteroatoms initially contained in the modified composition.

Description

[0001] TITLE: PROCESS FOR PURIFYING A PLASTIC LIQUEFACTION OIL COMPOSITION IN TURBULENT CONDITIONS AND USE

[0002] Field of invention

[0003] The present invention relates to a process for the turbulent purification of a composition comprising a plastic liquefaction oil and its subsequent use in refining and petrochemical processes. The process according to the invention makes it possible in particular to reduce the heteroatom concentration of feedstocks originating from plastic waste, in particular with a view to their use in a steam cracking process.

[0004] State of the art

[0005] Plastic waste is most often sent to landfills or incinerated, with a smaller portion directed toward recycling. However, there is a significant need, encouraged by regulations, to limit plastic waste in landfills. On the other hand, disposing of plastic waste in landfills is becoming increasingly difficult. Therefore, it is necessary to recycle plastic waste.

[0006] One possible way to recycle plastic is to liquefy the plastic through pyrolysis or hydrothermal liquefaction. However, the resulting plastic oil typically contains large amounts of dienes and heteroatoms, including metals. These numerous heteroatoms and metals are contaminants for the catalysts in the hydrotreatment processes commonly used to recycle plastics. Furthermore, dienes readily react to form gums. Dienes are also coke precursors in a steam cracker. Therefore, plastic liquefaction oils must be treated for recycling. There are many treatment processes available to reduce the heteroatom content of plastic liquefaction oils.

[0007] Patent application WO2020 / 020769 claims a series of processes for purifying a composition comprising at least 20 ppm of chlorine. Many recyclable liquid wastes can be treated, including plastic pyrolysis oils. The process sequence comprises a thermal treatment of the feedstock in the presence of an alkali metal hydroxide in order to obtain a reduction of at least 50% of the chlorine content relative to the feedstock, followed by hydrotreatment in order to obtain a further reduction of at least 50% of the chlorine content.

[0008] Patent application WO2021 / 105326 claims a method for the recovery of liquefied plastic waste comprising a step of pretreating the liquefied plastic waste by contacting it with an aqueous medium having a pH of at least 7 at a temperature of 200°C or higher, followed by a liquid-liquid separation in which the aqueous phase is separated from the organic phase, to produce a pretreated liquefied waste plastic material. The proposed solution comprises the use of a solution of NaOH in water. The separation of the aqueous and organic phases is carried out by physical (centrifugation) or chemical methods (addition of separation aid additives, for example non-aqueous solvents, addition of additional quantity of the aqueous medium used for contacting or of an aqueous medium having a different alkaline substance concentration), or by gravity.

[0009] Patent application US2014 / 0109465 claims a process for upgrading a hydrocarbon feedstock such as oil sand, crude oil, refinery hydrocarbon effluents, synthetic hydrocarbons, pyrolysis oils, renewable oils, etc., into upgraded hydrocarbon products having lower viscosity, lower density, lower sulfur content, and lower mineral / metal content. After being mixed with water, the feedstock is introduced into a high-rate reactor having a Reynolds number between 200 and 100,000, and subjected to high pressure (1500 and 6000 psig), and high temperature (400 and 700°C) with a residence time of less than 3 minutes to be converted by cracking, isomerization, cyclization, reforming, decarboxylation, and dehydration into a value-added hydrocarbon product. This document does not describe purification of the treated loads.

[0010] Patent application US10071322 claims a hydrothermal cleaning process and system for the rapid hydrolysis of renewable oils and the reduction of inorganic and organic contaminants. The process describes contacting the renewable oils with an aqueous medium and then introducing this mixture into a hydrothermal reactor in which the mixture is subjected to elevated temperatures between 300 and 500°C, high pressures between 34 and 414 bar and turbulent flow conditions that do not cause conversion of the feedstock. The turbulent flow in the hydrothermal reactor corresponds to a Reynolds number (Re) of at least 2000. The treatment described in this document requires elevated temperatures.

[0011] Most existing purification treatments are carried out at relatively high temperatures. Furthermore, these treatments do not provide means to reduce the silicon or alkali / alkaline earth metal content present in a plastic liquefaction oil after pretreatment with a base. However, it is known that the presence of alkali / alkaline earth metals can lead to the deactivation of catalysts used in catalytic processes for recycling purified plastic liquefaction oil.

[0012] There is therefore a need to improve existing purification processes.

[0013] Summary of the invention The invention aims to propose a method for purifying plastic liquefaction oil making it easier to purify it, in particular by limiting the operating temperature while maintaining high reduction performance in heteroatoms, and in particular in silicon, including for reducing the content of alkali and / or alkaline-earth metals resulting from the treatment of the plastic liquefaction oil with a basic compound containing, for example, an alkali or alkaline-earth metal.

[0014] For this purpose, the invention relates to a method for purifying the heteroatom concentration of a composition comprising a plastic liquefaction oil, comprising the following steps: a) providing a composition comprising a plastic liquefaction oil containing at least 20 ppm by mass of heteroatoms, b) bringing said composition into contact with an aqueous medium at a pH greater than 7, the contacting being carried out in a turbulent regime having a Reynolds number greater than 2000 and at a temperature less than or equal to 250°C to obtain an effluent containing the modified composition, c) subjecting the effluent from step (b) to (c1) washing in the presence of water or a solvent immiscible with the purified composition, (c2) separation, or to the succession of steps (c2) and (c1), and obtaining a purified composition having a reduced heteroatom content,and a phase containing the basic compound and heteroatoms initially contained in the modified composition.,

[0015] Step (b) of the present invention is a treatment carried out in turbulent mode, in particular in co-current and continuous mode, in the presence of an aqueous medium with a pH greater than 7, to allow the elimination of impurities containing heteroatoms, in particular alkali metals, alkaline earth metals, silicon, chlorine, bromine, iron, aluminum and others, likely to damage the catalyst of a subsequent hydrotreatment step.

[0016] The treatment in a turbulent regime makes it possible: to transfer the impurities present in the composition to be treated to an aqueous phase immiscible with the composition, the aqueous phase concentrated in impurities then being able to be separated, and / or to promote the reactions between the basic aqueous medium and the composition containing heteroatoms thanks to better contact between the oil to be treated and the basic aqueous solution. The impurities can then be removed by washing with a solvent immiscible with the composition and / or by separation of a phase immiscible with the composition containing the impurities. Step (b) according to the invention can be carried out by circulating said composition and the aqueous medium inside at least one tube equipped with at least one internal element capable of generating a turbulent regime.

[0017] Prior to step b) or during step (b), a basic compound may be added to an aqueous medium in an amount sufficient for the aqueous medium to have a pH greater than 7. Preferably, an aqueous compound may be added in an amount sufficient for the aqueous medium to have a pH greater than 10 or greater than 12, more preferably a pH of at least 12.5.

[0018] Advantageously, the basic compound may be added in an amount sufficient to saturate the aqueous medium.

[0019] The basic compound of step (b) may comprise an oxide, hydroxide, bicarbonate, or alkoxide of an alkali metal cation or an alkaline earth metal cation, or a hydroxide or bicarbonate of a quaternary ammonium cation, alone or in admixture.

[0020] Advantageously, the basic compound of step (b) may be chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2O, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, EtONa, MeONa, TEAOH, TBuOH, TMAOH, and mixtures thereof.

[0021] Step (c) according to the invention may comprise one or more of the following features: step (c) is preceded by a step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, or (iv) a combination of two or three of these steps. step c1) is carried out in the presence of water at neutral or acidic pH or in the presence of an organic solvent immiscible with the composition, preferably in the presence of water. step c2) is carried out by (i) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or three of these steps. step (c) comprises at least the separation step (c2) for separating the phase containing the basic compound and heteroatoms, and the purified composition, and the phase containing the basic compound and heteroatoms is returned in whole or in part to step (b).

[0022] Advantageously, prior to the treatment of step (b), said composition may be subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). Advantageously, (d) the purified composition of step (c) may undergo catalytic hydrotreatment, namely catalytic treatment under hydrogen, in one or two stages to provide a purified hydrotreated composition.

[0023] The hydrotreatment of step (d): can be carried out in a single step in which the purified composition of step (c) is hydrotreated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a hydrotreatment catalyst, or can be carried out in a first step (d-1) in which the purified composition of step (c) is hydrotreated, preferably selectively hydrogenated, at a temperature of 80 to 250°C, preferably 130 to 250°C in the presence of hydrogen at an absolute pressure of 5 to 60 bars, preferably 20 to 45 bars and in the presence of a first hydrotreatment catalyst, and in a second step (d-2) in which the effluent from from step (d-1) is hydrotreated at a temperature of 200 to 450°C, preferably 250 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars,preferably from 30 to 100 bars and in the presence of a second hydrotreatment catalyst.,

[0024] Advantageously, the purified and hydrotreated composition leaving step (d) can further be washed with water to remove inorganic compounds such as hydrosulfide, hydrogen chloride, ammonia.

[0025] Advantageously, the purified composition of step (c) or the hydrotreated purified composition of step (d) may be:

[0026] (f) used as such or separated into usable streams for the preparation of fuels and combustibles such as LPG, gasoline, diesel, heavy fuel oil, kerosene and / or for the preparation of lubricants and / or base oils, and / or treated, pure or diluted, optionally separated into usable streams, in:

[0027] (g) a steam cracker for producing olefins, and / or

[0028] (h) a fluidized bed catalytic cracker, and / or

[0029] (i) a hydrocracker, then optionally in a steam cracker, and / or

[0030] (i) a hydrotreatment reactor, in particular a catalytic hydrogenation reactor.

[0031] Preferably, the purified composition of step (c) or the hydrotreated purified composition of step (d) may be subjected, neat or diluted, optionally after separation into usable streams, to a steam cracking step (e) to produce olefins such as ethylene and propylene, which may then be used to manufacture new polymers by polymerization.

[0032] Advantageously, the product resulting from the effluent from step (c), in particular from the washing step (c1), or the hydrotreated effluent from step (d) can be purified by passing it over a solid adsorbent in order to reduce the content of at least one element among F, Cl, Br, I, O, N, S, Se, Si, P, As, Fe, Ca, Na, K, Mg and Hg and / or the water content.

[0033] The previously described steps of the method according to the invention can be implemented one after the other without an intermediate step except for the optional additional steps described.

[0034] The invention also relates to an installation, in particular adapted to the implementation of the method according to the invention, comprising an optional pretreatment section (A), a turbulent treatment section (B), in particular adapted for the implementation of step b), an optional solids separation section (C), a separation section (D), in particular adapted for the implementation of step c), an optional hydrotreatment section (E) and / or an optional treatment section in a steam cracker (F) and / or an optional treatment section in a hydrocracker (G) and / or an optional treatment section in a fluidized bed catalytic cracker (H) and / or an optional treatment section in a hydrotreatment reactor (I) and / or an optional section for preparing a fuel, a lubricant or base oil (J),in which the different sections are fluidically connected to implement the method according to the invention.,

[0035] Definitions

[0036] Hourly Volume Velocity (WH) is defined as the hourly volume of charge flow per unit of catalytic volume and is expressed here in h' 1 .

[0037] The terms "comprising" and "comprises" as used herein are synonymous with "including," "includes," or "contains," "containing," and are inclusive or unbounded and do not exclude additional features, elements, or method steps not specified.

[0038] The specification of a numeric domain without decimals includes all whole numbers and, where appropriate, fractions thereof (e.g., 1 to 5 may include 1, 2, 3, 4, and 5 when referring to a number of items, and may also include 1.5, 2, 2.75, and 3.80 when referring to, for example, a measure).

[0039] The specification of a decimal place also includes the decimal place itself (e.g., "from 1.0 to 5.0" includes 1.0 and 5.0). Any range of numerical values ​​recited herein also includes any subrange of numerical values ​​mentioned above. The expressions % by weight and % by mass have an equivalent meaning and refer to the proportion of the mass of a product relative to 100g of a composition comprising it.

[0040] Unless otherwise stated, measurements given in parts per million (ppm) are expressed by weight.

[0041] By "heteroatom" we mean any element of an organic compound other than carbon and hydrogen.

[0042] The expression "polar solvent" within the meaning of this patent application covers all chemical species, alone or in a mixture, comprising at least one carbon-hydrogen, carbon-halogen, carbon-chalcogen or carbon-nitrogen covalent bond and having a non-zero dipole moment. It is understood that the term "polar solvent" within the meaning of this definition specifically excludes water.

[0043] The term "solvent" includes the aforementioned "polar solvents" and non-polar solvents, which include, for example, any type of linear, branched, cyclic and / or aromatic saturated or unsaturated hydrocarbon such as pentane, cyclohexane, olefins, toluene or xylene or certain other solvents with zero or almost zero dipole moment such as tetrachloromethane or carbon disulfide.

[0044] The term "naphtha" refers to the general definition used in the oil and gas industry. Specifically, it is a hydrocarbon derived from the distillation of crude oil and has a boiling point between 15 and 250°C, according to ASTM D2887. Naphtha contains virtually no olefins because the hydrocarbons are derived from crude oil. It is generally considered that a naphtha has a carbon number between C5 and C11, although the carbon number can reach C15 in some cases. It is also generally accepted that the density of naphtha is between 0.65 and 0.77 g / mL.

[0045] “Liquefaction oil” means an oil resulting from a pyrolysis process and / or a hydrothermal liquefaction process of a hydrocarbon feedstock. This hydrocarbon feedstock may comprise plastics, biomass and / or elastomers, preferably plastics and / or biomass, alone or in a mixture, in particular in the form of waste. A liquefaction oil may be formed from a mixture of two or more liquefaction oils resulting from the liquefaction of different hydrocarbon feedstocks.

[0046] The pyrolysis process should be understood as a thermal cracking process, typically carried out at a temperature of 300 to 1000°C or 400 to 700°C, carried out in the presence or absence of a catalyst and / or a gas (fast pyrolysis, flash pyrolysis, catalytic pyrolysis, hydropyrolysis, steam pyrolysis, etc.). The hydrothermal liquefaction process (or HTL for "Hydrothermal Liquefaction" in English) is a thermochemical conversion process using water as a solvent, reactant and catalyst for the degradation reactions of a hydrocarbon feedstock, the water typically being in a subcritical or supercritical state. The hydrothermal liquefaction process is typically carried out at a temperature of 250 to 500°C and at pressures of 10 to 25-40 MPa in the presence of water.

[0047] The expression "plastic liquefaction oil" or "oil resulting from the liquefaction of plastic" or "plastic waste liquefaction oil" or "liquefaction oil resulting from the liquefaction of waste containing plastics" refers to the liquid hydrocarbon products obtained following pyrolysis or hydrothermal liquefaction of thermoplastic and / or thermosetting polymers, alone or in a mixture, and generally in the form of waste, optionally in a mixture with at least one other feedstock, in particular in the form of waste, such as biomass, for example chosen from lignocellulosic biomass, paper and cardboard, and / or an elastomer, for example possibly vulcanized latex or tires.In a particular embodiment, the thermoplastic and / or thermosetting polymers, alone or as a mixture, and generally in the form of waste, may be subjected to pyrolysis or hydrothermal liquefaction in a mixture with at least one other filler, in particular in the form of waste, such as biomass, for example chosen from lignocellulosic biomass, paper and / or cardboard. Preferably, this filler does not contain elastomers or contains less than 15% by mass, preferably less than 10% by mass or less than 5% by mass.

[0048] Plastic can be of any type, including any type of new or used plastic, included in household (post-consumer) or industrial waste. Plastics are understood to mean materials made of polymers and optionally auxiliary components such as plasticizers, fillers, colorants, catalysts, flame retardants, stabilizers, etc. For example, these polymers can be polyethylene, halogenated polyethylene (Cl, F), polypropylene, polystyrene, polybutadiene, polyisoprene, poly(ethylene terephthalate) (PET), acrylonitrile-butadiene-styrene (ABS), polybutylene, poly(butylene terephthalate) (PBT), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, polyamide, polycarbonate, polyether, epoxy polymer, polyacetal, polyimide, polyesteramide, silicone, etc.In general, any polymer or mixture of polymers capable of producing hydrocarbons by liquefaction, i.e. by pyrolysis and / or hydrothermal liquefaction, can be used.

[0049] Biomass can be defined as an organic plant or animal product. Biomass thus includes (i) biomass produced from surplus agricultural land not used for human or animal food: dedicated crops, called energy crops; (ii) biomass produced by deforestation (forest maintenance) or the clearing of agricultural land; (iii) agricultural residues from cereal crops, vines, orchards, olive trees, fruits and vegetables, agri-food residues, etc.; (iv) forest residues from forestry and wood processing; (v) agricultural residues from livestock farming (manure, slurry, bedding, droppings, etc.); (vi) household organic waste (paper, cardboard, green waste, etc.); (vii) ordinary industrial organic waste (paper, cardboard, wood, putrescible waste, etc.).The plastic liquefaction oil treated by the invention may originate from the liquefaction of waste containing at least 1% m / m, optionally from 1 to 50% m / m, from 2 to 30% m / m or in a range defined by any two of these limits, of one or more of the aforementioned biomasses, residues and organic waste, and the remainder consisting of plastic waste, optionally in a mixture with elastomers, in particular in the form of waste. In one embodiment, the waste does not contain elastomers or contains less than 15% by mass, preferably less than 10% by mass or less than 5% by mass.

[0050] Elastomers are linear or branched polymers transformed by vulcanization into a weakly crosslinked, infusible and insoluble three-dimensional network. They include natural or synthetic rubbers. They can be part of tire-type waste or any other household or industrial waste containing elastomers, natural and / or synthetic rubber, mixed or not with other components, such as plastics, plasticizers, fillers, vulcanizing agents, vulcanization accelerators, additives, etc. Examples of elastomeric polymers include ethylene-propylene copolymers, ethylene-propylene-diene terpolymer (EPDM), polyisoprene (natural or synthetic), polybutadiene, styrene-butadiene copolymers, isobutene-based polymers, isobutylene-isoprene copolymers, chlorinated or brominated, butadiene-acrylonitrile copolymers (NBR), and polychloroprenes (CR), polyurethanes, silicone elastomers, etc.The plastic liquefaction oil treated by the invention may come from the liquefaction of waste containing at least 1% m / m, optionally from 1 to 50% m / m, from 2 to 30% m / m or in a range defined by any two of these limits, of one or more of the aforementioned elastomers, in particular in the form of waste, the remainder being made up of plastic waste, optionally mixed with biomass, residues and organic waste.

[0051] The term "MAV" (acronym for "Maleic Anhydric Value") refers to the UOP326-82 method which is expressed in mg of maleic anhydride which react with 1 g of sample to be measured.

[0052] The term "Bromine Number" is the amount of bromine in grams reacted in 100 g of sample and can be measured according to ASTM D1159-07.

[0053] The term "Bromine Number" is the number of milligrams of bromine that react with 100 g of sample and can be measured according to ASTM D2710 or ASTM D5776. Boiling points as mentioned here are measured at atmospheric pressure unless otherwise stated. An initial boiling point is defined as the temperature value at which a first vapor bubble is formed. A final boiling point is the highest temperature attainable during distillation. At this temperature, no more vapor can be transported to a condenser.The determination of the initial and final points uses techniques known in the trade and several methods adapted according to the distillation temperature range are applicable, for example NF EN 15199-1 (2020 version) or ASTM D2887 for the measurement of boiling points of petroleum fractions by gas chromatography, ASTM D7169 for heavy hydrocarbons, ASTM D7500, D86 or D1160 for distillates.

[0054] Metal concentrations in hydrocarbon matrices can be determined by any known method. Acceptable methods include X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma atomic emission spectrometry (ICP-AES). Analytical scientists can identify the most suitable method for measuring each metal and, in general, each heteroelement, depending on the hydrocarbon matrix under consideration. Oxygen content can be measured according to the standard: ASTM D5622-17 / D2504-88(2015). Nitrogen content can be measured according to the standard: ASTM D4629-17. Sulfur content can be measured according to ISO 20846:2011. Halogen content, including chlorine, bromine, and fluorine, can be measured according to the standard: ASTM D7359-18.

[0055] "Hydrotreatment" means any process in which hydrocarbons react with dihydrogen, typically under pressure, in the presence of a catalyst or not. Hydrotreatment may thus comprise one or more reactions chosen from hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeoxygenation (HDO), hydrodemetalation (HCM), hydrocracking, hydroisomerization and hydrogenation (hydrogenation of unsaturated compounds into saturated compounds).

[0056] A "hydroprocessing catalyst" means a catalyst that promotes the incorporation of hydrogen into the products. This type of catalyst is typically a metal catalyst comprising one or more metals from groups 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14 of the periodic table.

[0057] The particular features, structures, properties, embodiments of the invention may be freely combined into one or more embodiments not specifically described herein, as may be apparent to those skilled in the art in the processing of plastic liquefaction oils using their general knowledge.

[0058] Detailed Description of the Invention Description of the composition comprising a plastic liquefaction oil

[0059] The composition provided in step (a) comprises a plastic liquefaction oil.

[0060] In a preferred embodiment, the composition may comprise only a plastic liquefaction oil.

[0061] Alternatively, the composition may comprise at least 1% by weight of plastic liquefaction oil. The remainder may then be composed of at most 99% by weight of a diluent or solvent such as a hydrocarbon and / or one or more of the components listed below, preferably a component derived from biomass, biomass waste and / or elastomeric waste. Preferably, the composition does not comprise a component derived from elastomeric waste or at a content of less than 15% by weight or 10% by weight or 5% by weight.

[0062] In one embodiment, the composition may comprise at least 5% by weight, preferably 10% by weight, more preferably at least 25% by weight, even more preferably at least 50% by weight, more preferably 75% by weight, even more preferably at least 90% by weight of plastic liquefaction oil. The composition may comprise at most 80% by weight or 90% by weight or 95% by weight or 100% by weight of plastic liquefaction oil. The mass content of plastic liquefaction oil(s) in the composition may be within any range defined by two of the limits previously set.

[0063] The composition may further comprise a component derived from biomass, biomass waste and / or elastomeric waste, such as tall oil, used edible oil, animal fat, vegetable oil such as rapeseed, canola, castor, palm, soybean oil, oil extracted from algae, oil extracted from fermentation of oleaginous microorganisms such as oleaginous yeasts, biomass liquefaction oil, in particular biomass liquefaction oil such as Panicum virgatum or lignocellulosic biomass liquefaction oil, for example wood, paper and / or cardboard liquefaction oil, oil obtained by liquefaction of crushed used furniture, elastomer liquefaction oil for example optionally vulcanized latex or tires, and mixtures thereof.

[0064] The composition may further comprise a component which is a diluent miscible with the plastic liquefaction oil. This diluent preferably has a diene number of at most 0.5 g 12 / 100 g, measured according to UOP 326-17, a bromine number of at most 5 g Br2 / 100 g, measured according to ASTM D1159. The diluent is preferably selected from a naphtha and / or a paraffinic solvent and / or a straight run diesel or gas oil, containing at most 1% by weight of sulfur, preferably at most 0.1% by weight of sulfur, and / or a hydrocarbon stream having a boiling range between 50°C and 150°C or a boiling range between 150°C and 250°C or a boiling range between 200°C and 350°C, preferably having a bromine number of at most 5 gBr2 / 100g, and / or a diene number of at most 0.5 gBr2 / 100g or any combination thereof.

[0065] The composition may have a bromine index of not more than 150 g Br2Z 100g, preferably not more than 100 g Br2 / 100g, even more preferably not more than 80 g Br2 / 100g, most preferably not more than 50 g Br2 / 100g, as measured according to ASTM D1159.

[0066] The composition may have a heteroatom content of at least 20 ppm.

[0067] Step (a) of providing the composition may comprise:

[0068] (a1) a step of liquefying waste containing plastics and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase,

[0069] (a2) a step of separating the liquid phase of said product, said liquid phase forming a plastic liquefaction oil,

[0070] (a3) an optional step of mixing the plastic liquefaction oil with a diluent or solvent.

[0071] The liquefaction step (a1) may comprise a pyrolysis step, typically carried out at a temperature of 300 to 1000°C or 400 to 700°C, this pyrolysis being for example a rapid pyrolysis or a flash pyrolysis or a catalytic pyrolysis or a hydropyrolysis.

[0072] Alternatively or in combination, the liquefaction step (a1) may comprise a hydrothermal liquefaction step, typically carried out at a temperature of 250 to 500°C and at pressures of 10 to 25-40 MPa.

[0073] The waste treated in step (a1) may be plastic waste optionally mixed with biomass and / or elastomers, as previously described, preferably mixed only with biomass (or biomass waste), or containing at most 15%m of elastomer waste, preferably at most 10%m or at most 5%m.

[0074] Separation step (a2) eliminates the gaseous phase, essentially C1-C4 hydrocarbons, and the solid phase (typically char) to recover only the liquid organic phase forming a liquefaction oil.

[0075] Plastic liquefaction oils contain, among other things, paraffins, i-paraffins (isoparaffins), dienes, alkynes, olefins, naphthenes and aromatics. Plastic liquefaction oils also contain impurities containing heteroatoms, such as chlorinated, oxygenated, sulfurous, nitrogenous and / or silylated organic compounds, metals, salts, phosphorus compounds. The composition of plastic liquefaction oil depends on the nature of the liquefied plastic, and optionally on any other waste liquefied with the plastic, and is essentially (in particular at more than 80% m / m, most often at more than 90% m / m) made up of hydrocarbons having from 1 to 150 carbon atoms and impurities.

[0076] A plastic liquefaction oil typically comprises 5 to 80% m / m of paraffins (including cycloparaffins), 10 to 95% m / m of unsaturated compounds (including olefins, dienes and acetylenes), 5 to 70% m / m of aromatics. These contents can be determined by gas chromatography.

[0077] In particular, a plastic liquefaction oil may comprise a Bromine number of 10 to 130 g Br / 100 g, as measured according to ASTM D1159, and / or a Maleic Anhydride Number (UOP326-82) of 1 to 55 mg maleic anhydride / 1 g.

[0078] In a preferred embodiment, said plastic liquefaction oil has an initial boiling point of at least 15°C, and a final boiling point of at most 800°C, preferably at most 600°C, even more preferably at most 560°C, more preferably at most 450°C, even more preferably at most 350°C, preferably 250°C (measured according to standard NF EN 15199-1 / 2).

[0079] A plastic liquefaction oil typically contains at least 20 ppm of heteroatoms, or even at least 30 ppm of heteroatoms.

[0080] A plastic liquefaction oil may include, but is not limited to, one or more of the following heteroatom contents: 0 to 8% w / w oxygen (measured according to ASTM D5622), 1 to 13000 ppm nitrogen (measured according to ASTM D4629), 2 to 10000 ppm sulfur (measured according to ISO 20846), 1 to 10000 ppm metals (measured by ICP), 50 to 6000 ppm chlorine (measured according to ASTM D7359-18), 0 to 200 ppm bromine (measured according to ASTM D7359-18), 1 to 40 ppm fluorine (measured according to ASTM D7359-18), 1 to 2000 ppm silicon (measured by XRF).

[0081] Detailed description of the optional composition pre-processing step

[0082] Between step (a) and (b), the invention may also comprise an optional pretreatment step, in which said composition is subjected, in particular immediately before step (b) or (c2), to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). This additional step may make it possible to reduce some of the impurities contained in the composition such as oxygen, nitrogen, chlorine, sulfur or other heteroatoms. In particular, the reduction in the amount of oxygen may make it possible to avoid the formation of solids and / or gels during step (c1). In the additional washing step (ii), the polar solvent or water / composition volume ratio may be from 1 / 99 to 90 / 10, from 10 / 90 to 90 / 10, from 20 / 80 to 80 / 20, from 30 / 70 to 70 / 30, from 35 / 65 to 65 / 35, from 35 / 65 to 60 / 40, or from 40 / 60 to 60 / 40.

[0083] When water is used for washing (ii), it may have an acidic, basic or neutral pH. An acidic pH may be obtained by the addition of one or more organic or inorganic acids. Examples of suitable organic acids include citric acid (CeHsO?), formic acid (CH2O2), acetic acid (CH3COOH). Examples of inorganic acids are sulfamic acid (H3NSO3), hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4). A basic pH may be obtained by the addition of alkali and alkaline earth metal oxides, alkali and alkaline earth metal hydroxides (e.g. NaOH, KOH, Ca(OH)2), alkali and alkaline earth metal bicarbonates and amines (e.g. triethylamine, ethylenediamine, ammonia).

[0084] The polar solvent may have a density greater or less than the density of the composition comprising a plastic liquefaction oil.

[0085] In particular, the density of the polar solvent may be 3 to 50% higher or lower than that of the composition.

[0086] The polar solvent is a solvent immiscible with the composition comprising a plastic liquefaction oil to be purified.

[0087] For example, the polar solvent (or a mixture of polar solvents where appropriate) may be considered immiscible when its recovery rate is greater than or equal to 0.95. This recovery rate is defined as the ratio of the volume of extract to the volume of initial solvent, this extract being a phase containing the solvent, immiscible with the composition containing a liquefaction oil, recovered after stirring and then decanting a mixture of one part by volume of solvent with twenty-five parts by volume of the composition containing a liquefaction oil to be purified, at atmospheric pressure and at a temperature of 20°C.

[0088] This recovery rate can be determined in particular by following the following procedure:

[0089] Introduction of 50 mL of composition containing a liquefaction oil into a flat-bottomed flask with a volume of 100 mL, using a precision pipette of + / -0.5 mL,

[0090] Introduce 2 mL of solvent into the flask, using a precision pipette + / -0.1 mL,

[0091] Insert a magnetic bar, close the balloon with a polypropylene stopper,

[0092] Stir the mixture on a mechanical stirrer plate at a speed of 500 rpm for 5 minutes. At the end of the 5 minutes, stop stirring and remove the magnetic bar using a magnetic rod.

[0093] Transfer the contents of the flask into a graduated tube with an accuracy of + / -0.05 mL for a volume less than or equal to 2 mL and an accuracy of + / -0.1 mL for a volume greater than 2 mL. Wait for complete demixing by decantation and measure the volume of the 2 phases using the graduations. Complete demixing is considered to be achieved when the volumes of the two phases no longer vary.

[0094] Acceptable immiscible polar solvents include (i) sulfur compounds, for example dimethyl sulfoxide, (ii) nitrogen compounds, for example N,N-dimethylformamide, (iii) halogenated compounds, for example dichloromethane or chloroform, (iv) ethylene glycol, or: glycol ethers, including in particular polyethylene glycol of chemical formula HO-(CH2-CH2-O)nH with a mass average molar mass of 90 to 800g / mol, for example diethylene glycol and tetraethylene glycol, polypropylene glycol of chemical formula H[OCH(CH3)CH2]nOH with a mass average molar mass of 130 to 800g / mol, for example dipropylene glycol and tetrapropylene glycol, dialkyl formamides, in which the alkyl group may comprise from 1 to 8 or from 1 to 3 carbon atoms, in particular dimethyl formamide (DMF), dialkyl sulfoxides, in which the alkyl group may comprise from 1 to 8 or from 1 to 3 carbon atoms,in particular dimethyl sulfoxide (DMSO) and sulfolane, compounds comprising a furan ring, cyclic carbonate esters, in particular comprising from 3 to 8 or from 3 to 4 carbon atoms, in particular propylene carbonate and ethylene carbonate.,

[0095] One or more of the above-mentioned solvents may be used. However, advantageously, only one of the above-mentioned solvents may be used provided that it is immiscible with the composition containing a liquefaction oil to be purified.

[0096] Preferably, the polar solvent may be ethylene glycol or a glycol ether, in particular polyethylene glycol of chemical formula HO-(CH2-CH2-O)nH with a mass average molar mass of 90 to 800g / mol or polypropylene glycol of chemical formula H[OCH(CH3)CH2]nOH with a mass average molar mass of 130 to 800g / mol, or a compound comprising a furan ring, or a cyclic carbonate ester, in particular propylene or ethylene carbonate, alone or as a mixture, preferably alone. In a preferred embodiment, the polar solvent is chosen from propylene carbonate, ethylene carbonate, ethylene glycol and polyethylene glycol of chemical formula HO-(CH2-CH2-O)nH with a mass average molar mass of 90 to 800g / mol, alone or as a mixture, preferably alone.

[0097] Description of the basic compound used in step (b)

[0098] Step (b) is carried out in the presence of an aqueous medium with a pH greater than 7, for example from 7.1 up to a pH going to saturation of the compound in water, preferably from 8 to 14, more preferably from 9 to 14, or in any interval defined by two of these limits. Preferably, a pH greater than 10, for example at least 10.5, or greater than 12, more preferably a pH of at least 12.5, will be chosen.

[0099] This basic aqueous medium is typically obtained by adding a basic compound to water, preferably a nucleophilic basic compound.

[0100] Advantageously, the amount of basic compound used is from 0.1 to 50% by weight, preferably at least 1% by weight, more preferably at least 3% by weight, even more preferably at least 5% by weight or even at least 10% by weight, relative to the total mass of the treated composition (composition provided by step (a)). For example, the amount of basic compound used may be from 0.1 to 15% by weight, more preferably with 1 to 15% by weight, even more preferably from 1 to 10% by weight, in particular from 1 to 5% by weight, relative to the total mass of the treated composition (composition provided by step (a)).

[0101] The basic compound in solution may be added to the composition provided in step (a) either before step (b) or during step (b). This addition of the basic compound to the composition may optionally be followed by a mixing step before carrying out step (b).

[0102] The basic compound is thus added to the composition in solubilized form in an aqueous medium, preferably in water.

[0103] Advantageously, the basic compound added in solubilized form may be in solution in an aqueous medium, preferably water, and the content of basic compound in the aqueous medium may be from 0.1 to 50% by mass, preferably from 15 to 50% by mass, more preferably from 25% to 50% by mass, more preferably from 40 to 50% by mass, even more preferably the aqueous medium is saturated with basic compound, in particular the aqueous medium contains just enough basic compound to obtain a saturated solution. Such a saturated solution may advantageously have a pH greater than 10 or greater than 12, more preferably a pH of at least 12.5.In one embodiment, the basic compound may comprise an oxide, hydroxide, bicarbonate, or alkoxide of an alkali metal cation or an alkaline earth metal cation, or a hydroxide or bicarbonate of a quaternary ammonium cation, for example, a tetramethylammonium (TMA+), tetraethylammonium (TEA+), tetrapropylammonium (TPA+), or tetrabutylammonium (TBA+) cation, alone or in a mixture. Preferably, the basic compound may comprise an oxide or hydroxide of the above, alone or in a mixture.

[0104] In a preferred embodiment, the basic compound may be selected from LiOH, NaOH, CsOH, Ba(OH)2, Na2O, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, EtONa, MeONa, TEAOH, TBuOH, TMAOH, and mixtures thereof. A preferred basic compound may be selected from NaOH, KOH and mixtures thereof, preferably in solution in water.

[0105] Detailed description of step b) of turbulent treatment

[0106] In step (b), the composition is treated under conditions effective to generate a turbulent regime, which enhance the transfer of impurities contained in the composition to an aqueous phase or an organic phase immiscible with the composition or which modify the impurities sufficiently to allow their separation with the composition. In particular, step (b) is carried out under conditions which do not cause conversion of the composition to be treated.

[0107] Advantageously, the basic compound added in step (b) is in solution in water, and the content of basic compound in the water may be from 0.1 to 50% by mass, preferably from 25% to 50% by mass, more preferably from 40 to 50% by mass, even more preferably the water is saturated with basic compound, in particular the water contains just enough basic compound to obtain a saturated solution.

[0108] In step (b), the volume ratio of the basic compound in solution in water / composition, i.e. the volume ratio of the mixture (basic compound + water) / composition, may be from 0.1 / 99.9 to 80 / 20, from 1 / 99 to 80 / 20, from 1 / 99 to 70 / 30, from 1 / 99 to 65 / 35, from 1 / 99 to 60 / 40, from 1 / 99 to 50 / 50, or in any interval defined by any two of the aforementioned limits.

[0109] The turbulent regime is obtained when the flow has a Reynolds number of at least 2000, preferably at least 3000, more preferably at least 4000, or even at least 10000.

[0110] The turbulent regime can advantageously be achieved by using at least one static mixer. That is, the composition and the aqueous medium are introduced into at least one tube equipped with at least one internal element capable of generating the turbulent regime having a Reynolds number of at least 2000. A static mixer is a device for continuous mixing of fluids in co-current mode, it allows mixing of fluids without the use of moving parts. The static mixer relies on a tubular body to produce the desired mixing and dispersion effects as the fluid flows through the fixed components of the mixer. The fluid is then divided, separated and pushed onto the internal element of the static mixer causing the fluid to move radially outwards leading to a difference in speed between the molecules of the fluid causing the fluid to mix.In general, the direction of rotation of the fluid changes in each internal element, thus receiving a rapid reversal of the inertial force, which also agitates the fluid. These two principles make it possible to reach the turbulent regime whose Reynolds number is at least 2000. The internal element can be helical, twisted, perforated ribbons with spikes or even fins or wire windings.

[0111] Step (b) may be carried out at a temperature of at most 250°C. In a preferred embodiment, step (b) may be carried out at a temperature of 80 to 250°C, preferably 90 to 230°C, more preferably 100 to 230°C, or in any interval defined by any two of these limits. These temperature ranges may advantageously be combined with the aforementioned pH ranges and / or basic compound contents of the aqueous medium in order to improve the purification of the oil.

[0112] Advantageously, during step (b), the composition provided in step (a) can be preheated, preferably in the presence of the aqueous medium comprising the basic compound, to the temperature for implementing step (b) before being subjected to the turbulent regime.

[0113] Step b) of treatment in turbulent regime can in particular be carried out for a duration of 1 minute to 2 hours, preferably 1 minute to 1 hour, more preferably 1 minute to 20 minutes or 1 minute to 16 minutes.

[0114] The turbulent treatment of step (b) may be carried out at a pressure of 1 to 100 bar, 5 to 80 bar, preferably 10 to 60 bar. It is recommended that the composition comprising the liquefaction oil and the basic compound are essentially in the liquid phase during the turbulent treatment.

[0115] The turbulent treatment of step (b) can be carried out in one, two or more steps, for example by passing the composition to be treated through one or more static mixers, for example placed in series and / or in parallel, capable of generating a turbulent regime.

[0116] The turbulent treatment of step (b) can be carried out in a shell-and-tube heat exchanger in which the at least one static mixer is located in at least one tube or in the bundle of tubes arranged inside a casing called a shell.

[0117] Step (b) may therefore comprise: pumping the composition to be treated and the basic compound through at least one static mixer. Alternatively, the composition to be treated and the basic compound may be pumped separately and mixed at the inlet of the static mixer, generating turbulent regime characteristics to remove impurities.

[0118] Step (b) (including for example the pumping and turbulent regime generation steps) may be repeated one or more times before performing step (c), either by returning the composition leaving the reactor to the inlet of the static mixer, or by using several static mixers in series.

[0119] Alternatively, step (b) (comprising for example the pumping and turbulent regime generation steps) and step (c) may be repeated one or more times, for example by returning the purified composition from step (c) to the input of step (b) or by using several units in series capable of implementing steps (b) and (c) successively.

[0120] At the end of step (b), the composition is thus modified because the impurities (the compounds containing heteroatoms) have been modified by the treatment of step (b). The modified composition obtained at the end of step (b) makes it possible to subsequently obtain a purified composition comprising a reduced heteroatom content, as explained below.

[0121] Detailed description of the optional additional solids separation step

[0122] Step (c), and in particular one or more of steps (c1) and (c2), may be preceded or followed by a step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps. This step of separating the solids is particularly advantageous before step (c2) because it can facilitate the separation of the phases by eliminating all or part of the solids present in the effluent from step (b).

[0123] During step (c), the effluent from step (b) may be subjected to (c1) washing with water or a solvent immiscible with the modified composition, (c2) separation, or to the succession of steps (c2) and (c1). This step (c) makes it possible to recover a purified composition having a reduced heteroatom content, and a phase containing the basic compound and heteroatoms initially contained in the modified composition. This step thus makes it possible to separate the impurities from the composition. It may make it possible to obtain a purified composition having in particular an alkali or alkaline-earth metal content of less than or equal to 2 ppm (by mass). The choice of steps (c1), (c2) or (c2) + (c1) may in particular be chosen according to the desired purification objective.

[0124] When step (c) implements separation (c2), it will be advantageous to recover the phase containing the basic compound recovered at the outlet of the separation step (c2) and return it in whole or in part to step (b) of treatment by hydrodynamic cavitation. This makes it possible to reduce the quantities of basic compound to be used and thus reduce the associated costs.

[0125] The washing step (c1) is carried out with water at neutral, basic or acidic pH or with a solvent immiscible with the purified composition. The washing step (c1) makes it possible to recover a phase containing the purified composition and a phase containing the water or the immiscible solvent used for washing, the basic compound and the impurities. In other words, at the outlet of the washing step, these phases are recovered separately, for example following a liquid / liquid separation (centrifugation and / or decantation and / or other) carried out at the end of the washing step.

[0126] This step (c1) makes it possible to eliminate the impurities containing heteroatoms present in the effluent containing the modified composition leaving step (b) by solubilizing them in a solvent (water or an organic solvent). It can make it possible to obtain a purified composition having in particular an alkali or alkaline-earth metal content of less than or equal to 2 ppm (by mass).

[0127] This washing step (c1) can also make it possible to separate the basic compound from the purified composition.

[0128] The basic compound used in step (b) being solubilized in an aqueous medium, immiscible with the composition, this washing step (c1) can be omitted.

[0129] The water used in step (c1) can have an acidic pH (pH<7), basic (pH >7) or neutral (PH=7).

[0130] In one embodiment, the water used has an acidic or neutral pH. In particular, the water used then does not contain a basic compound and in particular does not contain a basic compound comprising an alkali or alkaline-earth metal cation.

[0131] An acidic pH may be obtained by the addition of one or more organic or inorganic acids. Examples are cited with reference to wash (ii) of the optional pre-treatment step. Preferably, the water may have a pH of 0.1 to 6.9. A basic pH may be obtained by the addition of a basic compound, for example those cited above with reference to wash (ii) of the optional pre-treatment step or those used in step b). Preferably, the water may have a pH of 7.1 to 14.

[0132] The immiscible solvent may be any organic solvent immiscible with the composition, in particular in which the impurities containing heteroatoms are soluble. A usable immiscible solvent is, for example, a polar solvent, in particular those described in the optional pre-treatment step.

[0133] Step (c1) may be carried out at a temperature of 10°C to 120°C, preferably 15°C to 95°C, more preferably 15°C to 80°C, or in any range defined by any two of these limits, advantageously without external heating. Step (c1) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step (b) is carried out.

[0134] Step (c1) can be carried out on the effluent directly from step (b), without an intermediate step, or on the effluent containing the purified composition leaving step (c2). When it follows step (c2), the washing step (c1) then makes it possible to eliminate any residue of the basic compound and / or impurities containing heteroatoms, still present in the purified composition leaving step (c2), which can make it possible to obtain a purified composition having in particular an alkali or alkaline-earth metal content of less than or equal to 2 ppm (by mass).

[0135] During step (c1), the volume ratio of solvent or water / effluent containing the purified composition may be from 1 / 99 to 90 / 10, from 20 / 80 to 80 / 20, from 30 / 70 to 70 / 30, from 35 / 65 to 65 / 35, from 35 / 65 to 60 / 40, from 40 / 60 to 60 / 40, or in any interval defined by any two of the aforementioned limits.

[0136] Step (c1) may comprise, or consist of, bringing the effluent from step (b) or (c2) into contact with water or an immiscible solvent by any means known in the prior art.

[0137] For example, the effluent from step (b) or (c2) and the solvent or water may be introduced into tanks, reactors or mixers commonly used in the profession and the two components may be mixed. The contacting may comprise vigorous agitation of the two components by a mixing device. For example, the two components may be mixed together by stirring or shaking. Alternatively, the contacting may be carried out in an enclosure in which the two components circulate in countercurrent, for example in contact columns with suitable packing in order to increase the contact between the phase of the composition being treated and the water or an immiscible solvent. Alternatively, the contacting may be carried out in another static mixer in co-current mode or in a cavitation enclosure. This contacting may occur more than once, in particular under the conditions presented above.

[0138] The washing step (c1) can be carried out continuously or in batch.

[0139] The separation step (c2) also makes it possible to separate the purified composition to obtain a phase containing the purified composition having a reduced heteroatom content, and a phase containing the basic compound and the impurities. This is typically a liquid / liquid separation. It can advantageously be carried out by (i) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or two or three of these steps. It can make it possible to obtain a purified composition having in particular an alkali or alkaline-earth metal content of less than or equal to 2 ppm (by mass).

[0140] Step (c2) can be carried out directly on the effluent containing the modified composition from step (b). In this case, it makes it possible to separate the purified composition from the basic compound. This step (c2) then separates a phase containing the purified composition and a phase containing the aqueous medium (immiscible with the composition), the basic compound and the impurities. This phase containing the basic compound can then be returned to step (b) to reuse the basic compound. This makes it possible to reduce the total quantity of basic compound consumed in step (b).

[0141] Step (c2) can also be carried out on the effluent containing the purified composition obtained at the outlet of step (c1).

[0142] Prior to step (c2), the effluent containing the modified composition leaving step (b) or the effluent containing the purified composition leaving step (c1) may be treated in at least one mechanical or electrostatic coalescer in order to break any emulsion and concentrate the basic compound in the solvent or water.

[0143] Step (c2) may be carried out at a temperature of 10°C to 120°C, preferably 15°C to 95°C, more preferably 15°C to 80°C, or in any range defined by any two of these limits, advantageously without external heating. Step (c2) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step (b) is carried out.

[0144] The hydrotreatment of step (d) can be carried out in a single step or in two steps. When carried out in a single step, the effluent from step (c) is typically hydrotreated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a hydrotreatment catalyst, for example a catalyst of the NiMo (0.1-60% by mass) and / or CoMo (0.1-60% by mass) type generally on a support.

[0145] Alternatively, the hydrotreatment of step (d) can be carried out in a first step (d-1) in which the effluent from step (c) is hydrotreated, preferably selectively hydrogenated, at a temperature of 80 to 250°C, preferably 130 to 250°C in the presence of hydrogen at an absolute pressure of 5 to 60 bars, preferably 20 to 45 bars, and in the presence of a first hydrotreatment catalyst, preferably a hydrogenation catalyst, for example a hydrogenation catalyst comprising Pd (0.1-10% by weight) and / or Ni (0.1-60% by weight) and / or NiMo (0.1-60% by weight), and in a second step (d-2) in which the effluent from step (d-1) is hydrotreated at a temperature of 200 to 450°C, preferably from 250 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably from 30 to 100 bars and in the presence of a second hydrotreatment catalyst, for example a catalyst of the NiMo (0.1-60% by weight) and / or CoMo (0.1-60% by weight). The first step can then allow the hydrogenation of dienes initially present in the composition.

[0146] This step (d) can be carried out in a single reactor with several catalytic beds placed in series with possible hydrogen additions between the beds or in several reactors in series depending on the desired objective.

[0147] This hydrotreatment step can also have a demetallation, cracking, dearomatization function depending on the characteristics of the catalyst and the hydrotreatment conditions.

[0148] Preferably, the purified composition obtained after step (c) is sent to the hydrotreatment step without being cooled and / or depressurized to the temperature and pressure at the outlet of step (c). The feed for the hydrotreatment, containing at least a portion of the purified composition, may advantageously be heated by a heat exchanger which is supplied with the effluent from the hydrotreatment (given that the hydrotreatment is exothermic, the effluent from the hydrotreatment will have a higher temperature than the feed entering the hydrotreatment).

[0149] Preferably, the feedstock for the hydrotreatment, containing at least a portion of the purified composition, can be diluted with a portion of the hydrotreatment effluent, still having a higher temperature than the desired temperature at the inlet of the hydrotreatment. This at least partial recycling of the hydrotreatment effluent makes it possible to dilute the unsaturates present in the purified composition and to preheat the feedstock. Preferably, the portion of the hydrotreatment effluent which is not recycled but still at a high temperature, can exchange its sensible heat with the composition comprising a plastic liquefaction oil and thus ensure the preheating of this composition entering step (b).

[0150] The effluent from step (c) or the effluent from step (d) may be purified by passing it over a solid adsorbent in order to reduce the content of at least one element among F, Cl, Br, I, O, N, S, Se, Si, P, As, Fe, Ca, Na, K, Mg and Hg and / or the water content.

[0151] The adsorbent may be operated in regenerative or non-regenerative mode, at a temperature below 400°C, preferably below 100°C, more preferably below 60°C, chosen from: (i) a silica gel, (ii) a clay, (iii) a crushed clay, (iv) apatite, (v) hydroxyapatite and combinations thereof, (vi) an alumina, for example an alumina obtained by boehmite precipitation, a calcined alumina such as Ceralox ® from Sasol, (vii) boehmite, (viii) bayerite, (ix) hydrotalcite, (x) a spinel such as Pural ® or Puralox from Sasol, (xi) a promoted alumina, for example Selexsorb ® from BASF, an acid promoted alumina, an alumina promoted by a zeolite and / or by a metal such as Ni, Co, Mo or a combination of at least two of them, (xii) an acid-treated clay such as Tonsil ® from Clariant, (xiii) a molecular sieve in the form of an aluminosilicate containing an alkali or alkaline earth cation for example sieves 3A, 4A, 5A,13X, for example marketed under the brand Siliporite ® from Ceca, (xiv) a zeolite, (xv) an activated carbon, or the combination of at least two adsorbents, the adsorbent or the at least two adsorbents retaining at least 20% by weight, preferably at least 50% by weight of at least one element among F, Cl, Br, I, O, N, S, Se, Si, P, As, Fe, Ca, Na, K, Mg and Hg and / or water.,

[0152] According to a preferred embodiment, the adsorbent is regenerable, has a specific surface area of ​​at least 200 m 2 / g and is operated in a fixed bed reactor at less than 100°C with a WH of 0.1 at 10 h' 1 .

[0153] The effluent leaving the hydrotreatment step (d), namely the purified and hydrotreated composition, optionally purified by passing over a solid adsorbent, can be washed with water to remove inorganic compounds such as hydrosulfide, hydrogen chloride and ammonia before being subjected to subsequent treatments.

[0154] The purified composition leaving step (c) or the effluent leaving step (d) of hydrotreatment, optionally washed with water, can be fractionated into usable streams whose cut points are typically chosen according to the subsequent treatment. This fractionation is carried out according to distillation temperature ranges, for example to separate streams of the LPG, gasoline, diesel, heavy fuel oil, kerosene type, which can then be treated in a steam cracker and / or in a catalytic cracker and / or in a hydrocracker (then possibly in a steam cracker) and / or in a hydrotreatment reactor and / or used as such for the preparation of fuels, combustibles, lubricants or base oils. A person skilled in the art knows how to select the most suitable cuts for the subsequent treatment units according to the desired objective.

[0155] The purified composition of step (c) or the purified and hydrotreated composition of step (d) may also be used diluted, for example mixed with naphtha, gas oil or crude oil in order to obtain a concentration of purified plastic liquefaction oil ranging from 0.01% by weight to 50% by weight at the maximum; preferably from 0.1% by weight to 25% by weight, even more preferably from 1% by weight to 20% by weight at the inlet of the following treatment.

[0156] Detailed description of the optional steam cracking step (e)

[0157] Steam cracking step (e) can be carried out on the purified composition from step (c) with or without dilution with a conventional steam cracking feedstock, or on the hydrotreated purified composition from step (d) with or without dilution. Prior to this step (e), a distillation separation step can be carried out depending on the technology of the steam cracking furnaces.

[0158] This step (e) produces olefins such as ethylene and propylene and aromatics. Ethylene and propylene can then advantageously be converted into polyethylene and polypropylene respectively in a polymerization section.

[0159] Steam cracking step (e) consists of thermally cracking in one or more furnaces a mixture of the purified composition and / or the purified and hydrotreated composition and water vapor at high temperatures of the order of 650 to 1000°C, preferably 700 to 900°C, typically 750 to 850°C, under low pressures (1 to 3 bars). The cracking reaction is carried out in the absence of oxygen. The reaction time is usually very short, of the order of a few hundred milliseconds. These conditions make it possible to break the carbon-carbon bonds and to produce unsaturated hydrocarbons with molecules smaller than the feedstock introduced into the reactor(s). The effluents leaving the reactor(s) are then rapidly cooled to temperatures of 400 to 550°C in order to limit secondary reactions such as the polymerization of olefins, dienes and acetylenes.The cooled effluents are finally fractionated to recover light C2-C5 olefins, such as ethylene, propylene, butadiene, isobutene, n-butene and isoprene.

[0160] The purified composition of step (c) or the purified and hydrotreated composition of step (d) may be sent to the steam cracker without dilution. The purified composition of step (c) or the purified and hydrotreated composition of step (d) may also be blended with naphtha, gas oil or another crude oil cut to obtain a concentration of purified plastic liquefaction oil ranging from 0.01% by weight to a maximum of 50% by weight; preferably from 0.1% by weight to 25% by weight, even more preferably from 1% by weight to 20% by weight at the inlet of the steam cracker. The purified composition is then converted to olefins, such as ethylene and propylene, as well as aromatics.

[0161] In a preferred embodiment, the purified, or purified and hydrotreated, composition may be sent at least partially directly to a steam cracker without further dilution than the steam used for steam cracking, and preferably as the only stream sent at least partially to the steam cracker, to produce olefins, such as ethylene and propylene, and aromatics.

[0162] The steam cracker is known per se in the art. The feedstock to the steam cracker, in addition to the stream obtained by the inventive process, may be ethane, liquefied petroleum gas, naphtha, or gas oils. Liquefied petroleum gas (LPG) consists essentially of propane and butanes. Gas oils have a boiling range of about 200 to 350°C, and consist of C10 to C22 hydrocarbons, including essentially linear and branched paraffins, cyclic paraffins, and aromatics (including mono-, naphtho-, and polyaromatics).

[0163] In particular, the cracking products obtained at the outlet of the steam cracker may include ethylene, propylene and benzene, and possibly hydrogen, toluene, xylenes and 1,3-butadiene.

[0164] In a preferred embodiment, the outlet temperature of the steam cracker may be between 800 and 1200°C, preferably between 820 and 1100°C, more preferably between 830 and 950°C, more preferably between 840 and 920°C. The outlet temperature may influence the content of high-value chemicals in the cracking products obtained by the present process.

[0165] In a preferred embodiment, the residence time in the steam cracker, through the radiation section of the reactor where the temperature is between 650 and 1200°C, may be between 0.005 and 0.5 seconds, preferably between 0.01 and 0.4 seconds.

[0166] In a preferred embodiment, the steam cracking is carried out in the presence of water vapor in a ratio of 0.1 to 1.0 kg of steam per kg of hydrocarbon feedstock, preferably 0.25 to 0.7 kg of steam per kg of hydrocarbon feedstock in the steam cracker, preferably in a ratio of 0.35 kg of steam per kg of feedstock mixture, to obtain cracking products as defined above.

[0167] In a preferred embodiment, the reactor outlet pressure may be between 500 and 1500 mbar, preferably between 700 and 1000 mbar, more preferably may be about 850 mbar. The residence time of the feedstock in the reactor and the temperature must be considered together. A lower operating pressure makes it possible to facilitate the formation of light olefins and to reduce coke formation. The lowest possible pressure is obtained (i) by keeping the reactor outlet pressure as close as possible to atmospheric pressure at the cracking gas compressor suction (ii) by reducing the hydrocarbon pressure by dilution with steam (which has a substantial influence on slowing down coke formation). The steam / feedstock ratio can be maintained at a level sufficient to limit coke formation.

[0168] To the extent that the purified and / or purified and hydrotreated composition has a broad distribution in terms of carbon numbers (or boiling points) the vaporization of such a feedstock may be incomplete at the inlet of the reactors at the temperature where certain hydrocarbon molecules begin to decompose, the purified and / or purified and hydrotreated composition may then be preheated to a temperature at least 10°C below the decomposition temperature, then subjected to separation of the produced hydrocarbon vapors and the residual hydrocarbon liquid in a flash vessel. In this flash vessel the liquid exits from the bottom by gravity and the hydrocarbon vapors from the top. Optionally, the hydrocarbon liquid may be returned to the plastics liquefaction unit or to the optional hydrocracking step.

[0169] Detailed description of the optional hydrocracking step

[0170] Prior to steam cracking step (e), the hydrotreated effluent from step (d) may be subjected to a cracking reaction in order to reduce the length of the carbon chains of the paraffins present in the hydrotreated effluent.

[0171] Typically, this cracking reaction is a hydrocracking reaction carried out at a temperature of 250 to 480°C, a hydrogen partial pressure of 1.5 to 25 MPa abs. and an hourly volumetric flow rate of 0.1 to 10 h. -1 .

[0172] A usable hydrocracking catalyst comprises, for example, a support chosen from halogenated aluminas, combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites and a hydro-dehydrogenating function comprising at least one metal from group VIB chosen from chromium, molybdenum and tungsten, alone or as a mixture, and / or at least one metal from group VIII chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0173] In one embodiment, the hydrocracking step may be performed by adding a bed of hydrocracking catalyst downstream of the last hydroprocessing catalyst bed of the hydroprocessing section.

[0174] Description of the figures Figure 1 describes a possible embodiment of the invention. In this possible embodiment, the plastic liquefaction oil (1) is first optionally pretreated in the pretreatment section (A) to be subjected to an optional pretreatment (PTT) by (i) filtration, (ii) washing with water or a polar solvent, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). The pretreated oil (2) is then sent to a section (B) for treatment in a turbulent regime in the presence of a basic compound solubilized in water (3) implementing step (b) of the invention. The effluent (4) of step (b) can then be sent to an optional solids separation section (C). The effluent (5) leaving section (C) or the effluent (4) leaving section (B) is then sent to a separation section (D) implementing step (c) of the present invention.When this section implements step (c2), the phase (9) containing the basic compound can be returned to the turbulent treatment section (B). The effluent (6) leaving the section (D) can be sent to one or more of the following optional sections: an optional hydrotreatment section (HDT) (E), an optional treatment section (SC) in a steam cracker (F), an optional treatment section (HC) in a hydrocracker (G), an optional treatment section (FCC) in a fluidized catalytic cracker (H), an optional treatment section (HDT) in a hydrotreatment reactor (I), an optional preparation section (POOL) of a fuel, or a fuel or a lubricant or a base oil (J). The hydrotreatment section can comprise one or more hydrotreatment and / or selective hydrogenation units.Preferably, the effluent (7) leaving the hydrotreatment section (E) is then steam cracked to obtain olefins which can then be polymerized. Preferably, the effluent (7) leaving the hydrocracking section (E) is then steam cracked to obtain olefins which can then be polymerized.

[0175] Examples

[0176] Embodiments of the present invention are illustrated by the following non-limiting examples.

[0177] Example 1: Two-stage hydrotreatment and steam cracking of a plastic liquefaction oil

[0178] A purified plastic liquefaction oil leaving step (c) of the process according to the invention can be hydrotreated in two stages according to the following procedure:

[0179] The purified and washed liquefaction oil may be introduced into a first hydrotreatment section (HDT1) primarily to hydrogenate diolefins and acetylenes. This step may include a plurality of reactors in series and / or parallel if guard reactors are used upstream or downstream of the first hydrogenation reactor. These guard reactors may reduce the concentration of certain undesirable chemical species and / or elements such as chlorine, silicon, and metals. Particularly undesirable metals include Na, Ca, Mg, Fe, As, and Hg.

[0180] A second hydrotreatment section (HDT2) is dedicated to olefin hydrogenation and demetallation (HDM), desulfurization (HDS), denitrogenation (HDN) and deoxygenation (HDO). These two sections consist of one or more reactors operated in series, or in parallel, or both. Isolated, lead-lag, series and / or parallel guard reactors can be considered depending on the nature and quantity of the contaminant in the stream to be treated.

[0181] In the event that the treatment according to the invention does not allow sufficient reduction of impurities to be obtained, guard reactors to remove chlorine, metals and silicon can be added. Silicon can also be trapped on the upper bed of a reactor in section HDT2 or separately, upstream.

[0182] Chlorine and mercury can be separated by liquid or gas phase guard reactors.

[0183] Since the hydrotreating reactions in sections HDT1 and HDT2 are exothermic, quenching with cold hydrogen or dilution with an inert feedstock can be used to moderate the temperature increase and control the reaction. Dilution with an inert feedstock can be achieved by recycling the liquid fraction leaving the reactors.

[0184] There may be intermediate quenches between the beds or between the HDT1 and HDT2 reactors or no quenching. In the latter case, recycling of part of the flow leaving HDT1 or HDT2 must be carried out to control the temperature. Strict temperature control in HDT1 must be carried out to avoid clogging of the reactor and degradation of the catalytic hydrogenation conditions.

[0185] The operating pressure in each of the HDT1 and HDT2 hydrotreatments is 5-140 bars, preferably 20-45 bars for HDT1 and 20-140 bars, preferably 30-100 bars for HDT2, typically 30-45 bars for HDT2.

[0186] Typical temperature range at the inlet of HDT1 at the start of run (SOR): 150- 250°C. The catalyst for HDT 1 usually comprises Pd (0.1-10% by weight) and / or Ni (0.1 - 60% by weight) and / or NiMo (0.1-60% by weight).

[0187] Typical HDT2 inlet temperature range at start of run (SOR): 200-340°C. Typical HDT2 outlet temperature range (SOR): 300-380°C, up to 450°C. The catalyst for HDT 2 usually comprises a NiMo (any type of commercial catalyst for refining or petrochemical applications), potentially a CoMo in the very last beds at the bottom of the reactor (any type of commercial catalyst for refining or petrochemical applications).

[0188] The upper bed of the HDT2 should preferably be operated with a NiMo having hydrogenating capacity as well as silicon trapping capacity. Such an upper bed can be considered as a metal trap having also HDN activity and hydrogenating capacity. It is possible to have two separate beds in an HDT2 reactor, with quenching between the two beds or between the two reactors, if the two beds are in two separate reactors, or no quenching at all. Ideally, the intermediate quench is carried out using cold HDT2 effluent or by supplying cold hydrogen, i.e. at a temperature generally ranging from 15 to 30°C, in order to control the exotherm of the HDT2. Depending on the metals present in the liquefaction oil to be hydrotreated, a hydrodemetallization catalyst, for example a commercial one, can be added to the upper bed of the HDT2 section in order to protect the lower catalyst beds from deactivation.

[0189] The hydrotreated liquefaction oil leaving the HDT2 section, optionally after a water wash to remove inorganic compounds (hydrosulfide, hydrogen chloride, ammonia), can be used as is or fractionated according to distillation temperature ranges, to feed a steam cracker, an FCC, a hydrocracker, a catalytic reformer or a fuel pool such as LPG, gasoline, jet, diesel, fuel oil or a base oil pool.

[0190] In one embodiment, the hydrotreated liquefaction oil is sent to a hydrocracker. This hydrocracking comprises, for example, contacting the hydrotreated effluent with a hydrocracking catalyst, in the presence of H2 to produce an effluent meeting the specifications of a steam cracker in terms of final boiling point (<370°C).

Claims

Claims 1. A method for purifying a composition comprising a plastic liquefaction oil, comprising the following steps: a) providing a composition comprising a plastic liquefaction oil containing at least 20 ppm by mass of heteroatoms, b) contacting said composition with an aqueous medium at a pH greater than 7, the contacting being carried out in a turbulent regime having a Reynolds number greater than 2000 and at a temperature less than or equal to 250°C to obtain an effluent containing the modified composition, c) subjecting the effluent from step (b) to (c1) washing in the presence of water at neutral or acid pH or a solvent immiscible with the modified composition, or to the succession of a separation step (c2) and a step (c1), and obtaining a purified composition having a reduced heteroatom content, and a phase containing the basic compound and heteroatoms initially contained in the modified composition.

2. Method according to claim 1, characterized in that step (b) is carried out by circulating said composition and the aqueous medium inside at least one tube equipped with at least one internal element capable of generating a turbulent regime.

3. Method according to claim 1 or 2, characterized in that prior to step b) or during step (b), a basic compound is added to an aqueous medium in a quantity sufficient for the aqueous medium to have a pH greater than 7.

4. Method according to claim 3, in which step b) is characterized in that the basic compound comprises an oxide, a hydroxide, a bicarbonate, or an alcoholate of an alkali metal cation or an alkaline earth metal cation or a hydroxide or a bicarbonate of a quaternary ammonium cation, alone or as a mixture.

5. Method according to any one of claims 3 or 4, in which step b) is characterized in that the basic compound is chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2O, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, EtONa, MeONa, TEAOH, TBuOH, TMAOH, and mixtures thereof.

6. Method according to any one of claims 1 to 5, characterized in that step (c) comprises at least the separation step (c2) for separating the phase containing the basic compound and heteroatoms, and the purified composition, and in that the phase containing the basic compound and heteroatoms is returned in whole or in part to step (b). Method according to any one of claims 1 to 6, characterized in that the step (c) is preceded by a step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps. Process according to any one of claims 1 to 7, characterized in that step c2) is carried out by (i) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or three of these steps. Process according to any one of claims 1 to 8, in which, prior to the treatment of step (b), said composition is subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). Process according to any one of claims 1 to 9, in which: (d) the purified composition of step (c) undergoes a one- or two-step catalytic hydrotreatment to provide a hydrotreated purified composition. A process according to claim 10, characterized in that the hydrotreatment of step (d): - is carried out in a single step in which the purified composition of step (c) is hydrotreated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a hydrotreatment catalyst, or - is carried out in a first step (d-1) in which the purified composition of step (c) is hydrotreated at a temperature of 80 to 250°C, preferably 130 to 250°C in the presence of hydrogen at an absolute pressure of 5 to 60 bars, preferably 20 to 45 bars and in the presence of a first hydrotreatment catalyst, and in a second step (d-2) in which the effluent from step (d-1) is hydrotreated at a temperature of 200 to 450°C, preferably 250 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a second hydrotreatment catalyst. A process according to any one of claims 10 or 11, wherein the purified and hydrotreated composition leaving step (d) is further washed with water to remove inorganic compounds such as hydrosulfide, hydrogen chloride, ammonia.A process according to any one of claims 1 to 12, wherein the purified composition of step (c) or the hydrotreated purified composition of step (d) is. (f) used as such or separated into streams suitable for the preparation of fuels and combustibles such as LPG, gasoline, diesel, heavy fuel oil, kerosene and / or for the preparation of lubricants and / or base oils, and / or treated, pure or diluted, optionally separated into usable streams, in: (g) a steam cracker for producing olefins, and / or (h) a fluidized bed catalytic cracker, and / or (i) a hydrocracker, then optionally in a steam cracker, and / or (i) a hydrotreatment reactor, in particular a catalytic hydrogenation reactor. Plant comprising an optional pretreatment section (A), a turbulent treatment section (B), an optional solids separation section (C), a separation section (D), an optional hydrotreatment section (E) and / or an optional treatment section in a steam cracker (F) and / or an optional treatment section in a hydrocracker (G) and / or an optional treatment section in a fluidized bed catalytic cracker (H) and / or an optional treatment section in a hydrotreatment reactor (I) and / or an optional section for preparing a fuel or a combustible, a lubricant or a base oil (J), in which the different sections are fluidically connected to carry out the method according to any one of the preceding claims.

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