Method for the purification of a plastic liquefaction oil composition

Abstract

The invention relates to a method for purifying a composition comprising a plastic liquefaction oil, wherein: (a) a plastic liquefaction oil composition is provided, then (b) washed with a first aqueous solution to obtain an organic phase containing the washed composition and a first aqueous effluent, then (c) the organic phase from step (b) is treated in the presence of a basic compound at a temperature of at most 450°C to obtain an organic effluent comprising a treated composition, and (d) the organic effluent from step (c) is washed with a second aqueous solution to obtain a purified composition having a reduced heteroatom content, and a second aqueous effluent. In addition, during step (b), the first aqueous effluent is entirely or partially returned to step (d), and / or during step (d), the second aqueous effluent is entirely or partially returned to step (b).

Description

[0001] TITLE: PROCESS FOR PURIFYING A PLASTIC LIQUEFACTION OIL COMPOSITION

[0002] Technical field of the invention

[0003] The present invention relates to a method for purifying a composition comprising a plastic liquefaction oil and its subsequent use in refining and petrochemical processes. The method 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] Technological background

[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 heteroatoms, including metals and dienes. Many heteroatoms, including metals, are contaminants for the catalysts in hydrotreatment processes commonly used to recycle plastics. In addition, dienes readily react to form gums. Dienes are also coke precursors in a steam cracker. Therefore, pretreatment of plastic liquefaction oils is necessary for recycling.

[0007] There are many treatment processes to reduce the heteroatom content of plastic liquefaction oils.

[0008] Patent JP3776335 discloses a process for the dechlorination and denitrogenation of an oil from the catalytic or thermal cracking of plastic waste which is treated at different temperatures up to 425°C for 30 minutes in the presence of an aqueous solution of an alkaline compound of an alkali or alkaline earth metal at a pH greater than or equal to 7. The reaction product is then separated from the alkaline aqueous solution by liquid-liquid separation with ethyl ether.

[0009] Patent application WO2012 / 069467 claims a process for removing siloxanes from plastic pyrolysis oil by heat treatment between 200 and 350°C in the presence of an alkali metal hydroxide in solid or dissolved form. The use of 5% by weight calcium hydroxide at 225°C does not result in a reduction in the siloxane content (Table 5, p. 12 and lines 9 to 11, p. 13). At the end of the reaction, the pyrolysis oil is separated by distillation under reduced pressure.

[0010] Patent Fl 128848 describes a process sequence comprising a heat treatment of a plastic pyrolysis oil at at least 200°C in the presence of an aqueous alkaline solution. At the end of the reaction, the pyrolysis oil is separated from the alkaline aqueous phase. A final hydrotreatment makes it possible to obtain a steam cracker feed which is optionally washed with an acid solution before introduction into the steam cracker.

[0011] Patent application WO2020 / 020769 claims a process sequence 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.

[0012] 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, e.g. 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.

[0013] Most existing purification treatments are carried out at relatively high temperatures. Furthermore, these treatments do not provide means to reduce the silicon content, or alkali / alkaline earth metals present in plastic pyrolysis 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. In addition, known purification processes use high quantities of reagents and / or water.

[0014] There is therefore a need to improve existing purification processes.

[0015] Document WO2022 / 079053A1 describes a process for recovering hydrocarbons from a hydrocarbon liquid comprising aliphatic hydrocarbons, organic compounds containing heteroatoms, and optionally aliphatic hydrocarbons. In one embodiment, the feedstock is subjected to a first washing at a temperature of 4 to 300°C with a solvent which may be basic water. Then, after separation of the solvent, the feedstock thus washed is sent to an extraction column to be treated with a solvent which may be water at a pH of 6 to 8. The feedstock (separated from the water) leaving this extraction column is then sent to a second extraction column into which an extraction solvent and optionally water are introduced.At the outlet of this second extraction column, the feedstock is recovered on the one hand, and the extraction solvent, possibly mixed with water, on the other hand. This is then mixed with a demixing solvent (which can be water) and then sent to a decanter and a distillation column which separates the extraction solvent and the demixing solvent. The latter can then be reused for the first wash. However, this process is complex and requires the demixing solvent to be purified for reuse.

[0016] Summary of the invention

[0017] The invention aims to propose a method for purifying plastic liquefaction oil making it possible to facilitate its purification and to reduce the quantities of reagents and water used, while maintaining high heteroatom reduction performance, in particular silicon, including for the reduction of the alkali and / or alkaline-earth metal content resulting from the treatment of the plastic liquefaction oil with a basic compound containing, for example, an alkali or alkaline-earth metal.

[0018] For this purpose, the invention relates to a method for purifying a composition comprising a plastic liquefaction oil comprising the following steps:

[0019] (a) providing a composition comprising a plastic liquefaction oil, said composition containing at least 20 ppm by mass of heteroatoms,

[0020] (b) washing the composition provided in step (a) with a first aqueous solution to obtain an organic phase containing the washed composition and a first aqueous effluent containing the first aqueous solution and at least a portion of the heteroatoms initially contained in the composition,

[0021] (c) treating the organic phase of step (b) in the presence of a basic compound at a temperature of at most 450°C to obtain an organic effluent comprising a treated composition,

[0022] (d) washing the organic effluent from step (c) with a second aqueous solution and obtaining a purified composition having a reduced heteroatom content, and a second aqueous effluent containing the second aqueous solution, the basic compound and at least a portion of the heteroatoms initially contained in the treated composition, the method further comprising at least one of the following characteristics:

[0023] - during step (b), the first aqueous effluent is returned in whole or in part to step (d) and added to the second aqueous solution, - during step (d), the second aqueous effluent is returned in whole or in part to step (b) and added to the first aqueous solution, or constitutes the first aqueous solution.

[0024] The first washing step (b) makes it possible in particular to reduce the content of oxygenated compounds in the composition and also to limit the quantity of solids formed during step (c), while the second washing step (d) will make it possible to eliminate impurities containing heteroatoms, in particular alkali metals, alkaline earth metals, silicon, chlorine, bromine, iron, aluminium and others, as well as the basic compound used during the treatment step (c).

[0025] Surprisingly, the use of the first aqueous effluent and / or the second aqueous effluent in steps (d) and (b) respectively makes it possible to improve the treatment of the composition while limiting both the quantity of water used and the quantity of basic compound used. In particular, the method according to the invention makes it possible to reduce from 65 to 98% of one or more heteroatoms present in the composition. In particular, the method according to the invention makes it possible to obtain a purified composition having a silicon content of less than 2 ppm, and / or a metal content, in particular alkaline earth metals, of less than 2 ppm.

[0026] This advantage is more particularly observed when the first aqueous effluent is returned in whole or in part to step (d) and the second aqueous effluent is returned in whole or in part to step (b). The first and second aqueous effluents can then circulate in a circuit connecting the two washing sections implementing the two washing steps, optionally with the possibility of injecting fresh water into this circuit and / or of extracting a part of the aqueous phase circulating in the circuit.

[0027] Thus, in one embodiment, the first aqueous effluent and the second aqueous effluent circulate in a circuit connecting a first washing section implementing washing step (b) to a second washing section implementing washing step (d). This circuit thus forms a fluid circulation loop connecting, in particular directly, the first washing section and the second washing section, this loop bringing on the one hand the first aqueous solution from the first washing section to the second washing section, and on the other hand the second aqueous solution from the second washing section to the first washing section. Advantageously, this circuit is devoid of treatment sections except, optionally, one or more sections for separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of these techniques, to remove the solids.The circuit is therefore devoid of an extraction, distillation or similar column.

[0028] In order to maintain a constant water flow in this circuit, water can be topped up by regularly injecting water into the circuit, advantageously upstream of the second washing section. It is also possible to withdraw part of the fluid circulating in the circuit, preferably part of the first aqueous effluent, upstream of the water injection.

[0029] Thus, advantageously, water is injected into the circuit, optionally upstream of the second washing section, and optionally part of the fluid circulating in the circuit is withdrawn.

[0030] Advantageously, before entering step (c), the organic phase of step (b) can be preheated in a heat exchanger by the second effluent from step (c).

[0031] Step (c) according to the invention may comprise one or more of the following characteristics: step (c) is carried out in the presence of 0.1 to 50% by weight of basic compound relative to the total mass of the treated organic phase, prior to step c) or during step c), there is added to the organic phase of step b) (i) a solid basic compound, (ii) a basic compound previously solubilized in an aqueous medium, preferably water, or (iii) a basic compound previously solubilized in a solvent, the basic compound comprises an oxide, a hydroxide, a bicarbonate or an alcoholate of an alkali metal cation or of an alkaline-earth metal cation, or a hydroxide or a bicarbonate of a quaternary ammonium cation, alone or as a mixture, the basic compound may be chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2 <D, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, TBuOH, TEAOH, TMAOH, EtONa, MeONaet leurs mélanges,step c) is carried out at a temperature of 50 to 450°C, preferably 50 to 350°C, more preferably 50 to 250°C, more preferably still 50 to 225°C or 50 to 200°C, or even 90°C to 200°C or 150 to 200°C or in any interval defined by any two of these limits, step c) is carried out for a period of 0.1 seconds to 3 hours, preferably 0.1 seconds to 2 hours, more preferably 1 minute to 1 hour, even more preferably 1 minute to 20 minutes or 1 minute to 16 minutes.,

[0032] Step (c) according to the invention may be followed by a separation step during which the basic compound is separated from the effluent and returned in whole or in part upstream of step (c), advantageously at the inlet of step (c), the separation step being carried out by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation, or (v) a combination of two or more of these steps. Step (d) according to the invention may be followed by a step of separation of the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or more of these steps,

[0033] Advantageously, prior to the treatment of step (b), said composition may be subjected to (i) filtration, (ii) distillation, (iii) decantation, or (iv) the combination of two or three of steps (i) to (iii).

[0034] Advantageously, (e) the purified composition of step (d), pure or diluted, can undergo a catalytic hydrotreatment, namely a catalytic treatment under hydrogen, in one or two stages to provide a hydrotreated purified composition.

[0035] Hydrotreatment of step (e):

[0036] - can be carried out in a single step in which the purified composition of step (d) is hydrotreated at a temperature of 200 to 450°C, preferably 200 to 380°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

[0037] - can be carried out in a first step (e-1) in which the purified composition of step (d) 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 150 bars, preferably 20 to 100 bars and in the presence of a first hydrotreatment catalyst, and in a second step (e-2) in which the effluent from step (e-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 150 bars, preferably 30 to 100 bars and in the presence of a second hydrotreatment catalyst.

[0038] Advantageously, the purified and hydrotreated composition leaving step (e) can further be washed with water to remove inorganic compounds such as hydrosulfide, hydrogen chloride, ammonia.

[0039] Advantageously, the purified composition of step (d) or the hydrotreated purified composition of step (e) may be:

[0040] (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:

[0041] (g) a steam cracker for producing olefins, and / or

[0042] (h) a fluidized bed catalytic cracker, and / or

[0043] (i) a hydrocracker, then optionally in a steam cracker.

[0044] Preferably, the purified composition of step (d) or the hydrotreated purified composition of step (e) may be subjected, neat or diluted, optionally after separation into usable streams, to a steam cracking step (g) to produce olefins such as ethylene and propylene as well as aromatics such as toluene, xylene and benzene, which may then be used to manufacture new polymers by polymerization.

[0045] 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.

[0046] In particular, in a particularly preferred embodiment, the method may comprise one or more of the following features: in step (b), the first aqueous effluent is returned in whole or in part to step (d) and added to the second aqueous solution without an intermediate treatment step other than an optional step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps, in step (d), the second aqueous effluent is returned in whole or in part to step (b) and added to the first aqueous solution, or constitutes this first aqueous solution, without an intermediate treatment step other than an optional step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps.

[0047] The invention also relates to an installation comprising an optional pretreatment section (A), a first washing section (B), a treatment section (C), an optional separation section (S), a second washing section (D), an optional hydrotreatment section (E) and / or an optional section for preparing a fuel or a combustible or a lubricant or a base oil (F) and / or an optional treatment section in a steam cracker (G) and / or an optional treatment section in a fluidized bed catalytic cracker (H) and / or an optional treatment section in a hydrocracker (I) in which the different sections are fluidically connected to implement the method according to the invention.

[0048] Advantageously, the first washing section (B) and the second washing section (D) can be connected directly to each other without passing through another treatment section except for an optional solids separation section.

[0049] Definitions

[0050] 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 .

[0051] 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.

[0052] 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).

[0053] The specification of a decimal also includes the decimal itself (e.g., "from 1.0 to 5.0" includes 1.0 and 5.0). Any range of numeric values ​​recited here also includes any subrange of numeric values ​​mentioned above.

[0054] The expressions % by weight and % by mass have an equivalent meaning and refer to the proportion of the mass in grams of a product relative to 100g of a composition comprising it.

[0055] Unless otherwise stated, measurements given in parts per million (ppm) are expressed by weight.

[0056] By "heteroatom" we mean any element of an organic compound other than carbon and hydrogen.

[0057] 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. A naphtha is generally considered to have 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.

[0058] “Liquefaction oil” means an oil resulting from a pyrolysis process and / or a hydrothermal liquefaction process of a hydrocarbon feedstock. This hydrocarbon feedstock may include plastics, biomass and / or elastomers, 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.

[0059] 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, steampyrolysis, etc.).

[0060] Hydrothermal liquefaction (HTL) 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.

[0061] 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.

[0062] 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 consisting 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), polylactic acid (PLA), acrylonitrile-butadiene-styrene (ABS), polybutylene, poly(butylene terephthalate) (PBT), polyvinyl chloride (PVC), polyvinylidene chloride, a polyester, a polyamide, a polycarbonate, a polyether, an epoxy polymer, a polyacetal, a polyimide, a polyesteramide, silicone, etc.Generally speaking, any polymer or mixture of polymers capable of producing hydrocarbons by liquefaction can be used.

[0063] 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 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 biomasses, residues and organic waste, and the remainder consisting of plastic waste, optionally mixed with elastomers, in particular in the form of waste.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The term "Bromine Index" 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.

[0068] Boiling points as mentioned here are measured at atmospheric pressure, unless otherwise stated. An initial boiling point is defined as the temperature value from which a first vapor bubble is formed. A final boiling point is the highest temperature achievable 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 art 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.

[0069] 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 appropriate method for measuring each metal, and generally 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.

[0070] "Hydrotreatment" means any process in which hydrocarbons react with dihydrogen, typically under pressure, in the presence of a catalyst or not. Hydrotreatment may thus include 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).

[0071] A "hydrotreating 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.

[0072] 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.

[0073] Detailed description of the invention

[0074] Description of the composition comprising a plastic liquefaction oil

[0075] The composition provided in step (a) comprises a plastic liquefaction oil. This plastic liquefaction oil may be a plastic pyrolysis oil, a plastic hydrothermal liquefaction oil, or a mixture of both.

[0076] In a preferred embodiment, the composition may comprise only a plastic liquefaction oil. Alternatively, the composition treated by the method according to the invention may comprise at least 1% by mass, or even at least 2% by mass of plastic liquefaction oil(s). The remainder may then be composed of at most 99% by mass, respectively at most 98% by mass, of a diluent or solvent such as a hydrocarbon and / or one or more components listed below.

[0077] 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.

[0078] The composition may comprise one or more of the following components: a tall oil, a used edible oil, an animal fat, a vegetable oil such as rapeseed, canola, castor, palm, soybean oil, an oil extracted from an algae, an oil extracted from a fermentation of oleaginous microorganisms such as oleaginous yeasts, a biomass liquefaction oil, in particular a biomass liquefaction oil such as Panicum virgatum or a lignocellulosic biomass liquefaction oil, for example a wood, paper and / or cardboard liquefaction oil, an oil obtained by liquefaction of crushed used furniture, an elastomer liquefaction oil for example optionally vulcanized latex or tires, as well as mixtures thereof.

[0079] The composition may have a bromine count of at most 150 g Br2 / 100 g, preferably at most 100 g Br2 / 100 g, even more preferably at most 80 g Br2 / 100 g, most preferably at most 50 g Br2 / 100 g, as measured according to ASTM D1159.

[0080] The composition may have a heteroatom content of at least 20 ppm.

[0081] The other component may comprise any diluent miscible with the plastic liquefaction oil. This diluent preferably has a diene number of not more than 0.5 g I2 / 100 g, measured according to UOP 326-17, a bromine number of not more than 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.

[0082] Step (a) of providing the composition may comprise: (a1) a step of liquefying waste containing plastics and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase, (a2) a step of separating the liquid phase from said product, said liquid phase forming a plastic liquefaction oil,

[0083] (a3) an optional step of mixing the plastic liquefaction oil with a diluent or solvent.

[0084] 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 fast pyrolysis or a flash pyrolysis or a catalytic pyrolysis or a hydropyrolysis.

[0085] 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.

[0086] The waste treated in step (a1) may be plastic waste possibly mixed with biomass, as previously described.

[0087] 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.

[0088] A plastic liquefaction oil typically comprises 30 to 80% w / w of paraffins (including cycloparaffins), 10 to 95% w / w of unsaturated compounds (including olefins, dienes and acetylenes), 5 to 70% w / w of aromatics. These contents can be determined by gas chromatography.

[0089] In particular, a plastic liquefaction oil may comprise a Bromine number of 10 to 130 g Br / 100g, as measured according to ASTM D1159, and / or a Maleic Anhydride Number (UOP326-82) of 1 to 55 mg maleic anhydride / 1g.

[0090] A plastic liquefaction oil typically contains at least 20 ppm of heteroatoms, or even at least 30 ppm of heteroatoms,

[0091] 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).

[0092] Detailed description of the optional composition pre-processing step

[0093] Prior to the washing of step (b), generally 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), to (i) filtration, (ii) distillation, (iii) decantation, or (iv) the combination of two or three of steps (i) to (iii). 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 quantity of oxygen may make it possible to avoid the formation of solids and / or gels during step (d).

[0094] During this first washing step (b), the composition provided in step (a), optionally pretreated as previously described, is washed with a first aqueous solution to obtain an organic phase containing the washed composition and a first aqueous effluent containing the first aqueous solution and at least a portion of the heteroatoms initially contained in the composition. In other words, at the outlet of this first washing step, the organic phase and the first aqueous effluent are recovered separately, for example following a liquid / liquid separation (centrifugation and / or decantation and / or other such as by hydrocyclone or filtration) carried out at the end of the washing step. The washing step thus integrates a liquid / liquid separation.

[0095] This first aqueous solution can have a neutral pH (pH=7), basic (pH>7) or acid (pH<7).

[0096] This first aqueous solution may comprise water, and optionally some or all of the second aqueous effluent from the second washing step (d). In a particularly preferred embodiment, the second aqueous effluent may be returned in whole or in part to step (b) and added to the first aqueous solution, or constitute this first aqueous solution, without an intermediate treatment step other than an optional step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps.

[0097] In one embodiment, the first aqueous solution may comprise only the second aqueous effluent. In other words, the first aqueous solution then consists of the second aqueous effluent.

[0098] In a particularly preferred embodiment, the first aqueous solution may consist of water (acidic, basic or neutral) and / or the second aqueous effluent. The volume of the second aqueous effluent may be insufficient to carry out the first washing step. In this case, it may be necessary to add water to obtain the desired volume of first aqueous solution. However, most often, the volume of second aqueous effluent is sufficient to obtain the desired volume of first aqueous solution and constitute it entirely. When the second aqueous effluent from the second washing step (d) is used in whole or in part as the first aqueous solution in this step, the pH of the second aqueous solution will then generally be basic, which promotes the reduction of oxygenated compounds.

[0099] The first aqueous solution used may nevertheless have an acidic, basic or neutral pH, preferably a basic pH (pH>7). An acidic pH may be obtained by adding one or more organic or inorganic acids. Examples of organic acids that can be used 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 can be achieved 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).

[0100] However, preferably, no basic compound other than that present in the second aqueous effluent is added to the first aqueous solution.

[0101] This first step typically allows the elimination of all or part of the oxygenated compounds (carboxylic acids, esters, carbonyls, alcohols) initially contained in the composition.

[0102] Part, or even all, of the basic compound originating from the second aqueous solution and present in the first aqueous solution may be neutralized during this first washing step so that the first aqueous effluent may have a neutral, or even acidic, pH, promoting the separation of the basic compound during the implementation of the second washing step.

[0103] During this washing step (b), the volume ratio of first aqueous solution / composition 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.

[0104] Step (b) 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 (b) is typically carried out at atmospheric pressure.

[0105] Step (b) may comprise, or consist of, contacting the composition provided by step (a) with water and / or the second aqueous effluent in a washing section by any means known in the prior art.

[0106] For example, the composition provided by step (a) and the first aqueous solution 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 adequate packing in order to increase the contact between the phase of the composition being treated and water or an immiscible solvent. Alternatively, the contacting may be carried out in a static mixer in co-current mode or in a cavitation enclosure.

[0107] Contact may occur more than once, particularly under the conditions presented above.

[0108] The washing step (b) can be implemented continuously or in batch.

[0109] Detailed description of step (c)

[0110] Step (c) is a step of treating the organic phase of step (b) in the presence of a basic compound at a temperature of at most 450°C to obtain an organic effluent comprising a treated composition.

[0111] This treatment makes it possible in particular to modify compounds containing heteroatoms and to promote their subsequent elimination.

[0112] Generally speaking, it will be noted that, as a portion, or even the majority, of the oxygenated compounds initially present in the composition have been eliminated during the first washing step, the quantity of basic compound required in this treatment step can be reduced compared to a process not including this first washing step. The invention thus makes it possible to save up to 40%, or even more, of the quantity of basic compound used during step (c), but also to limit the corrosion problems linked to the presence of acidic oxygenated compounds and to limit the formation of solids during the washing step (d), facilitating the implementation of the latter. The invention can also make it possible to reduce the quantity of impurities to be eliminated remaining in the organic effluent comprising the treated composition leaving step (c), which can make it possible to reduce the quantity of water required during step (d).

[0113] Step (c) is carried out in the presence of a basic compound, preferably a nucleophilic basic compound.

[0114] Advantageously, the basic compound may have a pKa in water of at least 7.5.

[0115] Advantageously, the amount of basic compound used is from 0.1 to 50% by weight, preferably from 0.1 to 40% by weight, more preferably from 0.1 to 30% by weight, more preferably from 0.1 to 20% by weight, even more preferably from 0.1 to 15% by weight relative to the total mass of the treated composition (organic phase provided by step (b)). Preferably, the amount of basic compound used is at least 0.5% by weight, more preferably at least 1% by weight, even more preferably at least 3% by weight, even more preferably at least 5% by weight or even at least 10% by weight, and at most 50% by weight, 40% by weight, 30% by weight, 20% by weight or 15% by weight, relative to the total mass of the treated composition (organic phase provided by step (b)).

[0116] In one embodiment, during step (c), the organic phase may be brought into contact with 0.1 to 15% by mass of a basic compound, preferably in the presence of water, more preferably with 0.5 to 15% by mass of a basic compound, even more preferably with 1 to 15% by mass of a basic compound, in particular 3 to 15% by mass, or even 5 to 15% by mass or 10 to 15% by mass relative to the total mass of the composition treated, or in any interval defined by two of the preceding limits.

[0117] The basic compound may be added to the organic phase provided by step (b) either before step (c) or during step (c). This addition of the basic compound to the organic phase may optionally be followed by a mixing step before carrying out step (c).

[0118] The basic compound may be added to the organic phase in solid form or dissolved in an aqueous medium, preferably water. In particular, step (c) may be carried out without adding any solvent other than water or a solvent possibly already present in the composition.

[0119] Advantageously, the basic compound added in step (c) is in solution in water. Thus, during step (c), the organic phase may be brought into contact with an aqueous solution of a basic compound, preferably a basic compound comprising an alkali or alkaline-earth metal cation. A person skilled in the art will then choose a quantity of water sufficient to dissolve / solubilize the basic compound, preferably the smallest possible quantity of water, or just sufficient to saturate the water with the basic compound.

[0120] Alternatively, the basic compound can be added to the organic phase solubilized in a solvent, miscible or immiscible with said organic phase.

[0121] When the basic compound is solubilized in a solvent or in water, the person skilled in the art will then choose a quantity of solvent / water sufficient to dissolve / solubilize it, preferably the smallest possible quantity of solvent / water. The volume ratio of the solvent / water containing the basic compound / organic phase, i.e. the volume ratio of the mixture (basic compound + solvent or water) / organic phase, 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.

[0122] A solution, in particular an aqueous solution, saturated with basic compound may advantageously be used. Advantageously, the basic compound added in step (c) is in solution in water or in a solvent, and the content of basic compound in the water or solvent is 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 water (or the solvent) is saturated with basic compound, in particular the water (or the solvent) contains just enough basic compound to obtain a saturated solution. A miscible solvent that can be used may be a polar solvent comprising an alcohol function and / or an ether function, ideally chosen from C1 to C4 alcohols, preferably from methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, 2-methylpropan-1-ol, propylene glycol.

[0123] A usable immiscible solvent may be an immiscible polar solvent.

[0124] 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.

[0125] This recovery rate can be determined in particular by following the following procedure:

[0126] ■ 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,

[0127] ■ Introduce 2 mL of solvent into the flask, using a precision pipette + / -0.1 mL,

[0128] ■ Insert a magnetic bar, close the balloon with a polypropylene stopper,

[0129] ■ Stir the mixture on a mechanical stirrer plate at a speed of 500 rpm for 5 min,

[0130] ■ At the end of 5 minutes, stop stirring, remove the magnetic bar using a magnetic rod,

[0131] ■ 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.

[0132] 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) n-H with a mass average molar mass of 90 to 800g / mol, for example diethylene glycol and tetraethylene glycol, polypropylene glycol with the chemical formula H[OCH(CH3)CH2] n OH of 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.

[0133] 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.

[0134] Preferably, the polar solvent may be ethylene glycol or a glycol ether, in particular polyethylene glycol of chemical formula HO-(CH2-CH2-O) n -H with a mass average molar mass of 90 to 800g / mol or polypropylene glycol with the 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.

[0135] In a preferred embodiment, the polar solvent is selected from propylene carbonate, ethylene carbonate, ethylene glycol and polyethylene glycol of chemical formula HO-(CH2-CH2-O) n -H with a mass average molar mass of 90 to 800g / mol, alone or in a mixture, preferably alone.

[0136] 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, e.g., a tetramethylammonium (TMA) cation. + ), tetraethylammonium (TEA + ), tetrapropylammonium (TPA + ), tetrabutylammonium (TBA + ). Preferably, the basic compound may comprise a aforementioned oxide or hydroxide, alone or in a mixture.

[0137] 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, TMAOH, TEAOH, TBuOH, EtONa, MeONa, and mixtures thereof. A preferred basic compound may be selected from NaOH, KOH and mixtures thereof, preferably in solution in water.

[0138] The solvent used to solubilize the basic compound may be water, an alcohol, for example methanol or ethanol, or any other organic solvent capable of solubilizing the chosen basic compound, preferably water or an alcohol.

[0139] Step (c) may be carried out at a temperature of at most 450°C. In one embodiment, step (c) may be carried out at a temperature of 50 to 450°C, preferably 50 to 350°C, more preferably 50 to 250°C, more preferably still 50 to 225°C or 50 to 200°C, or even 90°C to 200°C or 150 to 200°C or in any range defined by any two of these limits.

[0140] Treatment step c) can be carried out at an absolute pressure of 0.1 to 100 bars, preferably 1 to 50 bars.

[0141] In a particularly preferred embodiment, step (c) is carried out for a period of 1 minute to 3 hours, preferably 1 minute to 1 or 2 hours, more preferably 1 minute to 20 minutes, preferably 1 minute to 16 minutes, at a temperature of at most 250°C, more preferably at most 225°C, even more preferably at most 200°C. In this particularly preferred embodiment, step (c) can be carried out at a temperature of at least 50°C, preferably at least 90°C, more preferably at least 150°C. In this particularly preferred embodiment, step (c) can be carried out at an absolute pressure of 0.1 to 100 bar, preferably 1 to 50 bar.

[0142] In this particularly preferred embodiment, the organic phase can advantageously be brought into contact with:

[0143] - 0.1 to 15% by mass of a basic compound, advantageously comprising an alkali or alkaline-earth metal cation, and preferably in the presence of water or an alcohol, preferably with 0.5 to 15% by mass of a basic compound, more preferably with 1 to 10% by mass of a basic compound (mass percentages of basic compound relative to the organic phase), and / or

[0144] - with water or an alcohol containing from 15 to 50% by mass of basic compound, preferably from 25% to 50% by mass, more preferably from 40 to 50% by mass (mass percentages of basic compound relative to water or alcohol), even more preferably with water saturated with basic compound.

[0145] A preferred strong base may be selected from LiOH, NaOH, CsOH, Ba(OH)2, Na2O, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, TMAOH, TEAOH, TBuOH, EtONa, MeONa and mixtures thereof. A more preferred strong base may be selected from NaOH, KOH and mixtures thereof, in particular for the implementation of the particularly preferred embodiment.

[0146] Detailed description of the optional additional separation step

[0147] Step (c) may be followed by a separation step during which the basic compound is separated from the organic effluent and returned in whole or in part upstream of step (c), advantageously at the inlet of step (c), the separation step being carried out by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation or (v) a combination of two or more of these steps. This makes it possible in particular to reduce the quantity of basic compound used during step (c).

[0148] This optional step allows the basic compound to be recovered in aqueous solution or in a solvent, or in solid form depending on the nature of the basic compound added in step (c). It could therefore be a liquid-liquid or liquid-solid separation depending on the case.

[0149] Detailed description of the optional additional solids separation step

[0150] Step (d) may be followed by a step of separating the solids from the effluent of step (c) or from the organic effluent of the optional separation step by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps. This optional step may facilitate the implementation of the subsequent treatment step (steps (e), (f), (g), (h)), in particular when the previously described optional separation step is not carried out.

[0151] Alternatively or in combination, this optional step can be implemented on the first aqueous effluent and / or on the second aqueous effluent.

[0152] Detailed description of the second washing step (d)

[0153] In step (d), the organic effluent from step (c) is subjected to washing with a second aqueous solution. This step (d) makes it possible to recover an organic phase which forms the purified composition having a reduced heteroatom content and a second aqueous effluent containing the second aqueous solution, the basic compound and at least some, or even all, of the heteroatoms initially contained in the treated composition. In other words, at the outlet of this second washing step, the organic phase and the second aqueous effluent are recovered separately, for example following a liquid / liquid separation (centrifugation and / or decantation and / or other such as by hydrocyclone or filtration) carried out at the end of the washing step. The washing step thus integrates a liquid / liquid separation.

[0154] This washing step (d) makes it possible to remove the impurities containing heteroatoms present in the organic effluent containing the treated composition leaving step (c) by solubilizing them in water. This washing step also makes it possible to separate the basic compound from the purified composition.

[0155] The second aqueous solution may comprise water, and optionally some or all of the first aqueous effluent from the first washing step (b). In a particularly preferred embodiment, the first aqueous effluent may be returned in whole or in part to step (d) and added to the second aqueous solution without an intermediate treatment step other than an optional step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps.

[0156] In one embodiment, the second aqueous solution may comprise only the first aqueous effluent.

[0157] In a particularly preferred embodiment, the second aqueous solution may consist of water (acidic, basic or neutral) and / or the first aqueous effluent. The volume of the first aqueous effluent may be insufficient to carry out the second washing step. In this case, it may be necessary to add water to obtain the desired volume of second aqueous solution.

[0158] In one embodiment, the second aqueous solution may comprise the first aqueous effluent to which water has been added, in particular water at neutral or acidic pH.

[0159] The second aqueous solution used in step (d) may have a basic pH, an acidic pH (PH<7) or neutral pH (pH=7). In particular, when the first aqueous solution is returned in whole or in part to the second washing step and in particular when the second aqueous solution is itself returned in whole or in part to the first washing step, the second aqueous solution used may contain the basic compound used in step (c) and may thus have a basic pH, generally weakly basic. An acidic pH may be obtained by adding one or more organic or inorganic acids. Examples of organic acids that can be used include citric acid (CeHsO?), formic acid (CH2O2), acetic acid (CH3COOH)'. Examples of inorganic acids are hydrochloric acid (HCl), sulfamic acid (H3NSO3), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4).Preferably, the water may have a pH of 0.1 to 6.9.

[0160] In a particularly preferred embodiment, during step (b), the first aqueous effluent is returned in whole or in part to step (d) and added to the second aqueous solution, and during step (d), the second aqueous effluent is returned in whole or in part to step (b) and added to the first aqueous solution. The first aqueous effluent and the second aqueous effluent can then circulate in a circuit forming a loop connecting a first washing section implementing washing step (b) to a second washing section implementing washing step (d). Such a circuit typically comprises a fluid circulation device (pump or other) and forms a circulation loop for the aqueous washing media used in steps (b) and (d).Advantageously, this circuit may comprise a water injection device for injecting water into the circuit and a withdrawal device, for extracting a portion of the fluid circulating in the circuit, so as to maintain a substantially constant flow rate of fluid between the two washing sections and / or to adjust the volume of liquid entering each washing section. Preferably, the withdrawal and / or the injection are carried out upstream of the second washing section, which may promote the control of the pH of the second aqueous solution, the injected water being able to advantageously have a neutral or acidic pH. Preferably, this circuit does not comprise a treatment section other than an optional solids separation section.

[0161] Step (d) 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 (d) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step (c) is carried out.

[0162] Step (d) can be implemented on the effluent directly from step (c), without an intermediate step.

[0163] In step (d), the volume ratio of second aqueous solution / effluent containing the treated 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.

[0164] Step (d) may comprise, or consist of, contacting the effluent from step (c) with water and / or the first aqueous effluent in a washing section by any means known in the prior art. Devices similar to those described with reference to step (b) may be used.

[0165] Contact may occur more than once, particularly under the conditions presented above.

[0166] The washing step (d) can be implemented continuously or in batch.

[0167] Detailed description of the optional catalytic hydrotreatment step (e)

[0168] The hydrotreatment of step (e) can be carried out in a single step or in two steps. When carried out in a single step, the purified composition from step (d) with or without dilution is hydrotreated at a temperature of 200 to 450°C, preferably 200 to 380°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.

[0169] Alternatively, the hydrotreatment of step (e) can be carried out in a first step (e-1) in which the purified composition from step (d) with or without dilution 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 150 bars, preferably 20 to 100 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 (e-2) in which the effluent from step (e-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 150 bars, preferably from 30 to 100 bars and in the presence of a second hydrotreatment catalyst, for example a NiMo type catalyst (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.

[0170] The purified composition from step (d) may be hydrotreated neat or diluted, for example with a hydrocarbon of fossil origin, such as naphtha, diesel or crude oil or another hydrocarbon of fossil origin. For example, a concentration of purified plastic liquefaction oil ranging from 0.01% by weight to a maximum of 50% by weight may be obtained; preferably from 0.1% by weight to 25% by weight, even more preferably from 1% by weight to 20% by weight at the inlet to the hydrotreatment.

[0171] This step (e) 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.

[0172] This hydrotreatment step can also have a demetallation, cracking, dearomatization function depending on the characteristics of the catalyst and the hydrotreatment conditions.

[0173] Preferably, the purified composition obtained after step (d) is sent to the hydrotreatment step without being cooled and / or depressurized to the temperature and pressure at the outlet of step (d). 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).

[0174] Preferably, the feedstock for the hydrotreatment, containing at least a portion of the purified composition, may be diluted with a portion of the hydrotreatment effluent, still having a higher temperature than the desired temperature at the inlet to 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.

[0175] Preferably, the part of the hydrotreatment effluent which is not recycled but still at a high temperature can exchange its sensible heat with the organic phase entering step (c) and thus ensure the preheating of the latter.

[0176] The purified composition from step (d) or the hydrotreated purified composition from step (e) may be purified by passing 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.

[0177] 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.,

[0178] 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 .

[0179] The effluent leaving hydrotreatment step (e), namely the purified and hydrotreated composition, optionally further purified by passing over a solid adsorbent, may be washed with water to remove inorganic compounds such as hydrosulfide, hydrogen chloride and ammonia before being subjected to further treatments.

[0180] The purified composition leaving step (d) or the effluent leaving step (e) 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.

[0181] The purified composition of step (d) or the purified and hydrotreated composition of step (e) may also be used diluted, for example mixed with naphtha, gas oil or crude oil in order to obtain, for example, 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 following treatment.

[0182] Detailed description of the optional steam cracking step (q)

[0183] Steam cracking step (g) can be carried out on the purified composition from step (d) with or without dilution, or on the hydrotreated purified composition from step (e) with or without dilution. Prior to this step (g), a separation step by distillation can be carried out depending on the technology of the steam cracking furnaces.

[0184] This step (g) allows the production of olefins such as ethylene and propylene and aromatics. Ethylene and propylene can then advantageously be converted respectively into polyethylene and polypropylene in a polymerization section.

[0185] Steam cracking step (g) 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.

[0186] The purified composition of step (d) or the purified and hydrotreated composition of step (e) may be sent to the steam cracker without dilution. The purified composition of step (d) or the purified and hydrotreated composition of step (e) may also be blended with naphtha, gas oil or crude oil 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.

[0187] 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.

[0188] 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).

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] To the extent that the purified and / or purified and hydrotreated composition has a broad carbon number (or boiling point) distribution, vaporization of such a feedstock may be incomplete at the reactor inlet at the temperature where some 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 and 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.

[0195] Detailed description of the optional hydrocracking step

[0196] Prior to steam cracking step (g), the purified effluent from step (d) or the purified and hydrotreated effluent from step (e) 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.

[0197] 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 .

[0198] 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 VI B chosen from chromium, molybdenum and tungsten, alone or as a mixture, and / or at least one metal from group VIII chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0199] 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.

[0200] Description of figures

[0201] [Fig. 1] Figure 1 depicts one possible embodiment of the invention. [Fig. 2] Figure 2 depicts another possible embodiment of the invention.

[0202] In the figures, the same sections are designated by the same references.

[0203] In the embodiment of Figure 1, the plastic liquefaction oil (1) is first optionally pretreated in the pretreatment section (A) to be subjected therein to a pretreatment (PTT) by (i) filtration (ii) distillation, (iii) decantation, or (iv) the combination of two or three of steps (i) to (iii). The pretreated oil (2) is then sent to a first washing section (B) implementing the first washing step (b) of the process to carry out a first washing W1 and obtain a first organic phase (3) and a first aqueous effluent (4). The organic phase (3) is then subjected to a treatment (TT) implementing step (c) in a treatment section (C) in the presence of a basic compound (5) to produce the effluent (6) containing the treated composition. The effluent (6) of step (c) can then be sent to one or more optional separation sections (S).This may be an optional section for separating the basic compound (7') contained in the effluent carried out by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation or (v) a combination of two or more of these steps, this basic compound (7') being able to be recycled at least in part in step (c) or upstream of it. Alternatively, it may be an optional section for separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps (in this case the recycle (7') is omitted). This optional section for separating the solids could be provided downstream of section (D). Both separation sections may also be provided.The second effluent (6) leaving the section (C) or the effluent (7) leaving the section (S) is then sent to a second washing section (D) implementing the second washing step (d) of the method to carry out a second washing W2 and obtain a second organic phase (8) and a second aqueous effluent (9). In the embodiment shown, the first aqueous effluent (4) leaving the first washing section (B) is sent to the second washing section (D) and the second aqueous effluent (9) leaving the second washing section (D) is sent to the first washing section (B).The second organic phase (8) leaving section (D), optionally after fractionation and / or dilution, may be sent to one or more of the following optional sections: an optional hydrotreatment section (H DT) (E) for implementing step (e), an optional preparation section (Pool) of a fuel or a combustible or a lubricant or a base oil (F), an optional treatment section (SC) in a steam cracker (G), an optional treatment section (FCC) in a fluidized bed catalytic cracker (H), an optional treatment section (HCK) in a hydrocracker (I). The hydrotreatment section may comprise one or more hydrotreatment and / or selective hydrogenation units. Preferably, the effluent (10) leaving the hydrotreatment section (E) is then steam cracked to obtain olefins which can then be polymerized.Preferably, the effluent (11) leaving the hydrocracking section (I) is then steam cracked to obtain olefins which can then be polymerized. In the example shown, the second organic phase (8) is sent directly to sections F, H, I, in which it can be treated, typically in a mixture with a hydrocarbon feedstock typical of these sections. Alternatively, the effluent (10) leaving section (E) could be sent directly to sections F, H, I, in which it can advantageously be treated without mixing with another feedstock.

[0204] In the embodiment of Figure 2, the plastic liquefaction oil (100) is introduced into a first washing section (B) to be subjected to the first washing W1. A first organic phase (101) and a first aqueous effluent (102) exit the first washing section (B). The first organic phase (101) is sent to the treatment section (C). Upstream of the treatment section (C), a basic compound (103) is added to the first organic phase (101), via a pipe and one or more valves. The mixture (104) of the organic phase (101) and the basic compound (103) then passes through two heat exchangers (105), (106) to be heated before entering the treatment section (C). The effluent (107) leaving the treatment section (C) is used in particular to heat the mixture (104) via the first heat exchanger (105).It can then be cooled in a third heat exchanger (108) before entering the second washing section (D) to be subjected to the second washing W2. A second organic phase (109) and a second aqueous effluent (110) exit the second washing section (D). The organic phase (109) forms the purified composition which can then be treated for example as described with reference to Figure 1.

[0205] In this embodiment, a circuit (111) connects the first and second washing sections (B) and (D) via a first line (112) running from the second washing section to the first and a second line (113) running from the first washing section to the second. This circuit (111) comprises a pump (114), a water injection line (115) and a withdrawal line (116), here located on the second line (113). Valves (117), (118) make it possible to close the withdrawal line (116) and the water injection line (115). The second aqueous effluent (110) can be sent entirely to the first washing section (B) as washing solution, as shown. As described with reference to Figure 1, optional pretreatment and separation sections could be provided.

[0206] In the embodiments shown in Figures 1 and 2, the first aqueous effluent and the second aqueous effluent do not undergo an intermediate treatment step between the washing sections. In an embodiment not shown, one and / or the other of the aqueous effluents could optionally be subjected to a solids separation step. Whatever the embodiment, it is not necessary to subject these aqueous effluents to additional treatment steps of the distillation and / or liquid-liquid extraction type.

[0207] Examples

[0208] Embodiments of the present invention are illustrated by the following non-limiting examples. of a liquefaction oil of

[0209] A purified plastic liquefaction oil leaving step d) of the process according to the invention can be hydrotreated in two stages according to the following procedure:

[0210] 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.

[0211] 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.

[0212] 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.

[0213] Chlorine and mercury can be separated by liquid or gas phase guard reactors.

[0214] 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.

[0215] 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 HDT 1 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.

[0216] The operating pressure in each of the HDT1 and HDT2 hydrotreatments is 5-150 bars, preferably 20-100 bars for HDT1 and 20-150 bars, preferably 30-100 bars for HDT2, typically 30-45 bars for HDT2.

[0217] 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).

[0218] 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).

[0219] 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 H DM 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.

[0220] Depending on the metals present in the liquefaction oil to be hydrotreated, a hydrodemetallization catalyst, for example commercial, can be added to the upper bed of the HDT2 section in order to protect the lower catalyst beds from deactivation.

[0221] 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.

[0222] 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).

[0223] 2: Material used:

[0224] A 1.5 L AISI-316L grade stainless steel autoclave equipped with mechanical agitation is charged with pyrolysis oil, a strong base in the form of NaOH and water.

[0225] The sum of the volume of pyrolysis oil and the volume of solvent or water introduced is close to 600 mL at room temperature, without taking into account the possible effects of volume variation during their mixing. The autoclave is closed and the gaseous headspace in the autoclave is swept with nitrogen for 30 minutes. The autoclave is then heated under autogenous pressure with stirring at a speed of 400 to 1500 rpm to a temperature of 225 °C for a period of 30 minutes, once the target temperature has been reached. The temperature rise rate is set at 30 °C / 10 minutes. At the end of the reaction, the autoclave is cooled to room temperature and then the mixture is discharged. Prior to the reaction, the oil can be pre-washed with a clean or recycled aqueous effluent with a mass ratio of 1:1.

[0226] At the end of the reaction, the cooled mixture removed from the autoclave is washed three times with clean or partially recycled water with, for each wash, a water / load volume ratio = 40 / 60.

[0227] Test 1: basic treatment without pre-wash

[0228] A HPP1 pyrolysis oil is subjected to the treatment in the presence of sodium hydroxide at 225°C previously described according to the conditions listed in Table 1. The pyrolysis oil was not subjected to pre-washing.

[0229] Table 1

[0230] Upon leaving the autoclave, the oil is washed 3 times as previously described. The 3 wash waters are collected and mixed. These wash waters are noted EA1, their pH and COD (Chemical Oxygen Demand) were measured, the values ​​are gathered in Table 5.

[0231] The oil recovered after washing in 3 times, noted HPP1-T1 was analyzed (contents of O, N, Cl, Si before and after treatment, and reduction), the results are gathered in table 4.

[0232] Test 2: pre-wash with dirty water followed by basic treatment A sample of HPP1 oil is pre-washed using the EA1 wash water generated during test 1, the HPP1:EA1 mass ratio is 1:1. The water recovered at the outlet of the pre-wash, noted EA2, was analyzed (see table 5).

[0233] Then the pre-washed HPP1 oil is subjected to the basic treatment previously described according to the conditions listed in Table 2.

[0234] Table 2

[0235] At the outlet of the autoclave, the oil is washed 3 times with clean water as previously described. The water from these 3 washes is recovered and analyzed (water EA3 in Table 5). The oil recovered after this wash, noted HPP1-T2, was analyzed (contents of O, N, Cl, Si before and after treatment and reduction), the results are gathered in Table 4.

[0236] Test 3: Pre-wash with clean water and basic treatment, final wash with recovery of pre-wash water

[0237] A sample of HPP1 oil is pre-washed using clean water, the HPP1:clean water mass ratio is 1:1. The pre-wash water, denoted EA4, is collected and analyzed. Then, the pre-washed oil is subjected to the basic treatment previously described in the conditions of Table 3. At the outlet of the autoclave, the oil is washed in 3 times as previously described with a mixture of EA4 pre-wash water and clean water (mass ratio 1:1). The water from these 3 washes is recovered and analyzed (EA5 water in Table 5).

[0238] The oil recovered after washing, noted HPP1-T3, was analyzed (O, N, Cl, Si contents before and after treatment and reduction), the results are gathered in table 4.

[0239] Table 3

[0240] Results

[0241] The analyses in Table 4 demonstrate the effectiveness of pre-washing, whether carried out with recycled water or not (tests 2 and 3), particularly in improving silicon reduction compared to test 1 carried out without pre-washing. Tests 2 and 3 also demonstrate that it is possible to reuse the wash and pre-wash water for the process, in one direction or the other without affecting efficiency.

[0242] The analyses in Table 5 show that the pH of the water resulting from the pre-wash is acidic, whereas the wash water after treatment with soda is basic. It should be noted that despite an initially high COD (Chemical Oxygen Demand), the recycled water used for the pre-wash or for the wash after basic treatment sees its COD increase, which highlights the capture of impurities.

[0243] Table 4

[0244] Table 5

[0245] (*) the analyses were carried out after filtration on pleated paper

Claims

Claims 1. A method of purifying a composition comprising a plastic liquefaction oil comprising the following steps (a) providing a composition comprising a plastic liquefaction oil, said composition containing at least 20 ppm by mass of heteroatoms, (b) washing the composition provided in step (a) with a first aqueous solution to obtain an organic phase containing the washed composition and a first aqueous effluent containing the first aqueous solution and at least a portion of the heteroatoms initially contained in the composition, (c) treating the organic phase of step (b) in the presence of a basic compound at a temperature of at most 450°C to obtain an organic effluent comprising a treated composition, (d) washing the organic effluent from step (c) with a second aqueous solution and obtaining a purified composition having a reduced heteroatom content, and a second aqueous effluent containing the second aqueous solution, the basic compound and at least a portion of the heteroatoms initially contained in the treated composition, the method further comprising at least one of the following characteristics: - during step (b), the first aqueous effluent is returned in whole or in part to step (d) and added to the second aqueous solution, - during step (d), the second aqueous effluent is returned in whole or in part to step (b) and added to the first aqueous solution, or constitutes this first aqueous solution.

2. Method according to claim 1, characterized in that the first aqueous effluent and the second aqueous effluent circulate in a circuit connecting a first washing section implementing washing step (b) to a second washing section implementing washing step (d).

3. Method according to claim 2, characterized in that water is injected into the circuit, optionally upstream of the second washing section, and optionally a portion of the fluid circulating in the circuit is withdrawn.

4. Method according to any one of claims 1 to 3, characterized in that it comprises at least one of the following characteristics: during step (b), the first aqueous effluent is returned in whole or in part to step (d) and added to the second aqueous solution without an intermediate treatment step other than an optional step of separation of the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps, in step (d), the second aqueous effluent is returned in whole or in part to step (b) and added to the first aqueous solution, or constitutes this first aqueous solution, without an intermediate treatment step other than an optional step of separation of 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 4, characterized in that prior to step (c) or during step (c), there is added to the organic phase of step b) (i) a solid basic compound, (ii) a basic compound previously solubilized in an aqueous medium, preferably water, or (iii) a basic compound previously solubilized in a solvent. Process according to any one of claims 1 to 5, in which step (c) comprises one or more of the following characteristics: - step c) is carried out in the presence of 0.1 to 50% m of basic compound relative to the total mass of the treated organic phase, - step (c) is carried out at a temperature of 50 to 450°C, preferably 50 to 350°C, more preferably from 50 to 250°C, more preferably still from 50 to 225°C or from 50 to 200°C, - step (c) is carried out for a period of 0.1 seconds to 3 hours, preferably 0.1 seconds to 2 hours, more preferably 1 minute to 1 hour, even more preferably 1 minute to 20 minutes or 1 minute to 16 minutes, - 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 in mixture, - the basic compound is chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2 <D, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, TMAOH, TEAOH, TBuOH, EtONa, MeONa et leurs mélanges. Procédé selon l’une quelconque des revendications 1 à 6, caractérisé en ce que l’étape (c) is followed by a separation step during which the basic compound is separated from the effluent and returned in whole or in part upstream of step (c), advantageously at the inlet of step (c), the separation step being carried out by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation or (v) a combination of two or more of these steps. Process according to any one of claims 1 to 7, characterized in that step (d) is 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. 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) a distillation, (iii) decantation, or (iv) the combination of two or three of steps (i) to (iii). A process according to any one of claims 1 to 9, wherein: (e) the purified composition of step (d), pure or diluted, undergoes a catalytic hydrotreatment in one or two stages to provide a hydrotreated purified composition. A process according to claim 10, characterized in that the hydrotreatment of step (e): - is carried out in a single step in which the purified composition of step (d) is hydrotreated at a temperature of 200 to 450°C, preferably 200 to 380°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 (e-1) in which the purified composition of step (d) 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 150 bars, preferably 20 to 100 bars and in the presence of a first hydrotreatment catalyst, and in a second step (e-2) in which the effluent from step (e-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 150 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 (e) 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 (d) or the hydrotreated purified composition of step (e) is (f) used as such or separated into streams usable 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 streams usable, 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. Plant comprising an optional pretreatment section (A), a first washing section (B), a treatment section (C), an optional separation section (S), a second washing section (D), an optional hydrotreatment section (E) and / or an optional section for preparing a fuel or a combustible or a lubricant or base oil (F) and / or an optional treatment section in a steam cracker (G) and / or an optional treatment section in a fluidized bed catalytic cracker (H) and / or an optional treatment section in a hydrocracker (I), wherein the different sections are fluidically connected to implement the method according to any one of the preceding claims.

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