WO2024126961A1

WO2024126961A1 - Method for treating a plastic liquefaction oil composition by gasification

Info

Publication number: WO2024126961A1
Application number: PCT/FR2023/052019
Authority: WO
Inventors: Anne Vilbé; Thomas COUSTHAM; Paola GAUTHIER-MARADEI; Hélène COULOMBEAU-LEROY; Michael Hecquet; Katell Le Lannic
Original assignee: Totalenergies Onetech
Priority date: 2022-12-16
Filing date: 2023-12-15
Publication date: 2024-06-20
Also published as: FR3143623A1

Abstract

A method of purifying a composition comprising a plastic liquefaction oil, comprising treating the composition to reduce the content of heteroatoms by treatment with a basic compound followed by washing, separation or separation followed by washing. The composition thus treated is then subjected to a gasification process to produce syngas comprising at least dihydrogen, carbon monoxide and carbon dioxide.

Description

METHOD FOR TREATING A PLASTIC LIQUEFACTION OIL COMPOSITION BY GASIFICATION

Field of the invention

The present invention relates to a process for valorizing a composition comprising a plastic liquefaction oil by gasification. The process according to the invention makes it possible in particular to reduce the concentration of heteroatoms in the fillers coming from plastic waste, with a view to their use in a gasification process.

State of the art

Plastic waste is most often directed to landfills or incinerated, and a smaller portion is directed to recycling. However, there is a significant need, encouraged by regulations, to limit plastic waste in landfills. On the other hand, the disposal of plastic waste in landfills is becoming increasingly difficult. It is therefore necessary to recycle plastic waste.

A possible route to recycling plastic is the liquefaction of plastic by pyrolysis or hydrothermal liquefaction. The liquid thus obtained can then be introduced into a gasification process to complete the plastic recycling process. However, the resulting plastic oil generally contains large quantities of dienes and heteroatoms, including chlorine. These numerous heteroatoms, and in particular chlorine, are contaminants for gasification processes. In addition, dienes react easily by forming gums and chlorine causes corrosion problems. It is therefore necessary to treat plastic liquefaction oils to be able to recycle them. There are many treatment methods to reduce the heteroatom content of plastic liquefaction oils.

Patent application W02020/020769 claims a sequence of processes for purifying a composition comprising at least 20 ppm of chlorine. Many recyclable liquid wastes can be treated, including plastic pyrolysis oils. The process sequence includes a heat treatment of the charge in the presence of an alkali metal hydroxide in order to obtain a reduction of at least 50% in the chlorine content relative to the charge, followed by a hydrotreatment in order to obtain a new reduction of at least 50% in chlorine content.

Patent application WO2021/105326 claims a process for recovering liquefied plastic waste comprising a step of pre-treating the liquefied plastic waste by bringing it into contact with an aqueous medium having a pH of at least 7 at a temperature of 200°C or more , followed by liquid-liquid separation in which the aqueous phase is separated from the organic phase, to produce pretreated liquefied waste plastic. The proposed solution includes the use of a solution of NaOH in water. There separation of the aqueous and organic phases is carried out by physical methods (centrifugation) or chemical methods (addition of separation aid additives, for example non-aqueous solvents, addition of additional quantity of the aqueous medium used for the implementation contact or an aqueous medium having a different alkaline substance concentration), or by gravity.

Most existing purification treatments are carried out at relatively high temperatures. Due to the very high levels of contaminants in plastic liquefaction oils, these treatments are not economically viable. Furthermore, gasification processes require a charge with a very low heteroatom content, and in particular chlorine, to be able to function correctly and limit the risk of corrosion.

There is therefore a need for a process for treating plastic liquefaction oils before injection into a gasification process which is less expensive.

Summary of the invention

The invention aims to provide a process for treating plastic liquefaction oil by gasification including a purification treatment. In particular, this purification treatment can be carried out at relatively low temperature while maintaining high reduction performance, in heteroatoms, and in particular in chlorine. The purification treatment also makes it possible to reduce the content of the liquefaction oil in alkali and/or alkaline earth metals already present and/or which were introduced during the treatment of the plastic liquefaction oil with a basic compound containing , for example, an alkali or alkaline earth metal.

To this end, the invention relates to a process for treating by gasification a composition comprising a plastic liquefaction oil, comprising the following steps: a) providing a composition comprising a plastic liquefaction oil containing at least 20 ppm by mass of heteroatoms, in particular at least 20 ppm by mass of chlorine, b) bringing the composition provided in step a) into contact with a basic compound at a temperature of at most 450 ° C to obtain a first effluent containing a composition modified, c) subjecting the first effluent from step b) to (c1) washing with water or a solvent immiscible with the modified composition, (c2) separation, or to the succession of steps (c2) and (c1), and obtain a second effluent containing a purified composition having a reduced heteroatom content, and a phase containing the basic compound and heteroatoms initially contained in the modified composition, d) optionally, the second effluent from step c ) is separated by distillation into at least two distinct fractions, e) subjecting the second effluent from step c) or one of the fractions from step d), alone or mixed with another hydrocarbon feedstock, to a gasification process to produce synthesis gas comprising at least hydrogen, carbon monoxide and carbon dioxide.

Advantageously, prior to the treatment of step b), said composition can be subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv).

Step b) according to the invention may comprise one or more of the following characteristics: step b) is carried out in the presence of 0.1 to 50% m of basic compound relative to the total mass of the composition treated , prior to step b) or during step b), (i) a solid basic compound is added to the composition of step a), (ii) a basic compound previously dissolved in an aqueous medium, preferably water, or (iii) a basic compound previously dissolved in a solvent, preferably a polar solvent immiscible with said composition, the basic compound comprises an oxide, a hydroxide, a bicarbonate or an alcoholate of a cation of an alkali metal or an alkaline earth metal cation, or a hydroxide or a bicarbonate of a quaternary ammonium cation, alone or in a mixture, preferably the basic compound comprises an oxide, a hydroxide, a bicarbonate 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 a mixture, the basic compound can be chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2Û, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , NH4OH, TMAOH, TEAOH, TBuOH, MeONa, EtONa and mixtures thereof, preferably the basic compound can be chosen from LiOH, NaOH, CsOH, Ba(OH) ₂ , Na ₂ O, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , NH4OH, TMAOH, TEAOH, TBuOH, and their mixtures, step b) is carried out at a temperature of 50 to 450 °C, preferably 50 to 350 °C, more preferably 50 to 250 °C, even more preferably 50 to 225 °C. C, from 50 to 200 °C, from 70 to 190 °C or from 80 to 185 °C, or in any interval defined by any two of these limits, step b) of contacting is carried out for a duration from 0.1 second to 3 hours, preferably from 0.1 second to 2 hours, more preferably from 1 minute to 1 hour, even more preferably from 1 minute to 20 minutes or from 1 minute to 16 minutes.

Step c) according to the invention may comprise one or more of the following characteristics: step c1) is carried out in the presence of water at neutral, basic or acidic pH, or in the presence of an organic solvent immiscible with the composition, preferably in the presence of water, step c2) is carried out by (i) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or three of these steps, step c) comprises at least the separation step (c2) to separate the phase containing the basic compound and heteroatoms, and the purified composition, and the phase containing the basic compound and heteroatoms is returned in whole or in part to step b), step c) is preceded or followed, in particular immediately preceded or followed by a step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or more of these steps, step c) is followed by a purification 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, optionally implemented before the optional separation step d), step c) is followed by a catalytic hydrotreatment, namely a catalytic treatment under hydrogen, in one or two steps to provide a purified hydro-treated composition, optionally used before optional separation step d). The purified and hydrotreated composition thus obtained can also be washed with water to eliminate inorganic compounds such as hydrosulfide, hydrogen chloride, ammonia, before being sent to step d) or e ).

The synthesis gas produced during step e) can be (i) treated in a purification unit, (ii) treated in a Fischer-Tropsch process (in particular to produce paraffins), (iii) used as fuel ( energy recovery, in particular by cogeneration), and/or (iv) used in an alcohol production unit by fermentation or catalytic route. These different units are well known. In particular, the purification units can be chosen in the usual way depending on the objective and the gasification process used, in particular to remove any tar possibly present.

The previously described steps of the process according to the invention can be implemented one after the other without any intermediate step apart from the optional additional steps described.

The invention also relates to an installation, in particular adapted to the implementation of the method according to the invention, comprising an optional pretreatment section (A), a treatment section (B), at least one optional section (S1, S2) solids separation, a separation section (C), an optional hydrotreatment section (HDT), an optional distillation section (D) and a gasification section (E), in which the different sections are fluidly connected to put implement the process according to the invention. Definitions

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

The terms "comprising" and "includes" as used herein are synonymous with "including", "includes" or "contains", "containing", and are inclusive or unlimited and do not exclude additional features, unspecified elements or method steps.

The specification of a number domain without decimal places includes all whole numbers and, where appropriate, fractions thereof (for example, 1 to 5 may include 1, 2, 3, 4 and 5 when reference is made to a number of elements, and may also include 1.5, 2, 2.75 and 3.80, when reference is made to, for example, a measurement.).

Specifying a decimal also includes the decimal itself (for example, "from 1.0 to 5.0" includes 1.0 and 5.0). Any range of numerical values recited herein also includes any subrange of numerical values mentioned above.

The expressions % by weight and % by mass (denoted %m) have an equivalent meaning and refer to the proportion of the mass in grams of a product compared to 100 g of a composition comprising it.

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

By “heteroatom”, we mean any elements of an organic compound other than carbon and hydrogen.

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

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

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

By “liquefaction oil”, we mean an oil resulting from a pyrolysis process and/or a hydrothermal liquefaction process of a hydrocarbon feedstock. This hydrocarbon filler may include plastics, biomass and/or elastomers, alone or in a mixture, particularly in the form of waste. A liquefaction oil can be formed from a mixture of two or more liquefaction oils originating from the liquefaction of different hydrocarbon feedstocks.

The pyrolysis process must 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.).

The hydrothermal liquefaction process (or HTL for “Hydrothermal Liquefaction” in English) is a thermochemical conversion process using water as a solvent, reagent and catalyst for degradation reactions of a hydrocarbon feedstock, 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.

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” or even “plastic oil » refers to liquid hydrocarbon products obtained following pyrolysis or hydrothermal liquefaction of thermoplastic and/or thermosetting polymers, alone or in mixture, and generally in the form of waste, optionally in mixture with at least one other load, in particular in the form of waste, such as biomass, for example, chosen from lignocellulosic biomass, herbaceous biomass (biomass of plants having a non-woody stem and which die at the end of the growing season) and /or aquifer biomass (plants growing in water or underwater such as algae), paper and cardboard, and/or an elastomer, for example possibly vulcanized latex or tires.

Plastic can be of any type, including any type of new or used plastic, included in household (post-consumer) or industrial waste. By plastics we mean materials made up of polymers and optionally auxiliary components such as plasticizers, fillers, dyes, catalysts, flame retardants, stabilizers, etc. For example, these polymers can be polyethylene, halogenated polyethylene (Cl, F ), polypropylene, polystyrene, polybutadiene, polyisoprene, poly (terephthalate ethylene) (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. In general, any polymer or mixture of polymers capable of producing hydrocarbons by liquefaction can be used.

Biomass can be defined as an organic plant or animal product, namely a product composed of agricultural or forestry plant material or composed of animal material, including vegetable or animal oils or fats. Biomass thus includes (i) biomass produced by surplus agricultural land, not used for human or animal food: dedicated crops, called energy crops; (ii) biomass produced by deforestation (forest maintenance) or cleaning of agricultural land; (iii) agricultural residues from cereal crops, vines, orchards, olive trees, fruits and vegetables, agri-food residues, etc.; (iv) forest residues from silviculture and wood processing; (v) agricultural residues from livestock (manure, slurry, litter, droppings, etc.); (vi) organic household waste (paper, cardboard, green waste, etc.); (vii) ordinary industrial organic waste (paper, cardboard, wood, putrescible waste, etc.); (viii) algal biomass, namely biomass formed from algae, for example micro-algae (the algal biomass can be a suspension of algae obtained by harvesting algae coming for example from a bioreactor, or an algae residue obtained by dehydration of a suspension of algae) or macro-algae; (ix) herbaceous biomass. The plastic liquefaction oil treated by the invention can come from the liquefaction of waste containing at least 1%m, optionally from 1 to 50%m, from 2 to 30%m or in an interval 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.

Elastomers are linear or branched polymers transformed by vulcanization into an infusible and insoluble, weakly crosslinked three-dimensional network. They include natural or synthetic rubbers. They may 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 agent, 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, copolymers isobutylene isoprene, chlorinated or brominated, acrylonitrile butadiene copolymers (NBR), and polychloroprenes (CR), polyurethanes, silicone elastomers, etc. The plastic liquefaction oil treated by the invention can come from the liquefaction of waste containing at least 1%m/m, optionally from 1 to 50%m, from 2 to 30%m or in an interval defined by any two of these limits, of one or more aforementioned elastomers, in particular in the form of waste, the remainder consisting of plastic waste, optionally mixed with biomass, residues and organic waste.

The expression “MAV” (acronym for “Maleic Anhydric Value” for “maleic anhydride index”) refers to the UOP326-82 method which is expressed in mg of maleic anhydride which reacts with 1 g of sample to be measured .

The expression “Bromine number” corresponds to the quantity of bromine in grams reacted on 100 g of sample and can be measured according to the ASTM D1159-07 method.

The term “Bromine Index” is the number of milligrams of bromine that react with 100 g of sample and can be measured according to the ASTM D2710 or ASTM D5776 methods.

Boiling points as mentioned here are measured at atmospheric pressure unless otherwise noted. An initial boiling point is defined as the temperature value at which a first vapor bubble is formed. A final boiling point is the highest temperature 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 trade and several methods adapted depending on the range of distillation temperatures are applicable, for example NF EN 15199-1 (version 2020) or ASTM D2887 for measuring the points d boiling of petroleum fractions by gas chromatography, ASTM D7169 for heavy hydrocarbons, ASTM D7500, D86 or D1160 for distillates.

The concentration of metals 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). Specialists in analytical sciences know how to identify the most suitable method for measuring each metal and generally each heteroelement depending on the hydrocarbon matrix considered. The oxygen content can be measured according to the standard: ASTM D5622-17 / D2504-88 (2015). The nitrogen content can be measured according to the standard: ASTM D4629-17. The sulfur content can be measured according to the ISO 20846:2011 standard. The halogen content, in particular chlorine, bromine, fluorine, can be measured according to the standard: ASTM D7359-18.

By “hydrotreatment” we mean any process during which hydrocarbons react with dihydrogen, typically under pressure, in the presence of a catalyst or not. The hydrotreatment can thus comprise one or more reactions chosen from hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeoxygenation (HDO), hydro-demetallation (HCM), hydrocracking, hydroisomerization and hydrogenation (hydrogenation of unsaturated compounds to saturated compounds) .

By “hydrotreatment catalyst”, we mean a catalyst promoting the incorporation of hydrogen into 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.

The particular characteristics, 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 processing of plastic liquefaction oils using their general knowledge.

Detailed description of the invention

In the description which follows, the different embodiments described, and in particular the preferred embodiments of each step, can be combined according to the desired objective.

Description of the composition comprising a plastic liquefaction oil

The composition provided in step a) comprises a plastic liquefaction oil. This plastic liquefaction oil may be a plastic pyrolysis oil, a hydrothermal plastic liquefaction oil or a mixture of the two.

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

Alternatively, the composition provided in step a) may comprise at least 1%m, or even at least 2%m of plastic liquefaction oil(s). The remainder can then be composed of at most 99%m, respectively at most 98%m, of a diluent or solvent such as a hydrocarbon and/or one or more components listed below.

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

The composition may further comprise one or more of the components originating from biomass, biomass waste or elastomeric waste, such as the following components: a tall oil, a used edible oil, an animal fat, a vegetable oil such as 'a rapeseed, canola, castor, palm, soybean oil, an oil extracted from a 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 or herbaceous or aquiferous biomass liquefaction oil, for example an oil from liquefaction of wood, herbs, algae, paper and/or cardboard, an oil obtained by liquefaction of crushed used furniture, an oil from liquefaction of elastomers for example possibly vulcanized latex or tires, as well as their mixtures.

The composition may further include a component that is a diluent miscible with the plastic liquefaction oil. This diluent preferably has a diene number of at most 0.5 g I2/I OO g, measured according to UOP 326-17, a bromine number of at most 5 g Br2/100 g, measured according to ASTM D1159. The diluent is preferably chosen from a naphtha and/or a paraffinic solvent and/or a diesel or a straight-run 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 not more than 5 g Br2/100 g, and/or a diene number of not more than 0.5 g I2/100g or any combination thereof.

The composition may have a bromine number 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, the most preferred being not more than 50 g Br2/100 g, as measured according to ASTM D1159.

Step (a) of providing the composition may include:

(a1) a step of liquefying waste containing plastics and obtaining a hydrocarbon product comprising a gas phase, a liquid phase and a solid phase, (a2) a step of separating the liquid phase of said product, said liquid phase forming a plastic liquefaction oil,

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

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 hydropyrolysis.

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.

The waste treated in step (a1) can be plastic waste possibly mixed with biomass or other types of waste, as previously described. The separation step (a2) makes it possible to eliminate the gas phase, essentially the C1-C4 hydrocarbons and the solid phase (typically char) to recover only the liquid organic phase forming a liquefaction oil.

Plastic liquefaction oils contain paraffins, i-paraffins (isoparaffins), dienes, alkynes, olefins, naphthenes and aromatics. Plastic liquefaction oils also contain impurities containing heteroatoms, such as chlorinated, oxygenated, sulfurous, nitrogenous and/or silylated organic compounds, metals, salts, phosphorus compounds.

The composition of the plastic liquefaction oil depends on the nature of the liquefied plastic, and optionally on any other waste liquefied with the plastic, and is essentially (in particular more than 80% m, most often more than 90% m) consisting of hydrocarbons having 1 to 150 carbon atoms and impurities.

A plastic liquefaction oil typically comprises 5 to 80 wt% paraffins (including cyclo-paraffins), 10 to 95 wt% unsaturated compounds (including olefins, dienes and acetylenes), 5 to 70 wt% %m aromatics. These contents can be determined by gas chromatography.

In particular, a plastic liquefaction oil may include a Bromine number of 10 to 130 g Br2/100 g, as measured according to standard ASTM D1159, and/or a maleic anhydride index (UOP326-82) of 1 to 55 mg of maleic anhydride/1 g.

In a preferred embodiment, said plastic liquefaction oil has an initial boiling point of at least 15°C, and a final boiling point of not more than 800°C, preferably not more than 600°C. °C, even more preferably at most 560 °C, more preferably at most 450 °C, even more preferably at most 350 °C, preferably 250 °C (measured according to standard NF EN 15199- 1/2).

A plastic liquefaction oil typically comprises at least 20 ppm of heteroatoms, or even at least 30 ppm of heteroatoms. Its maximum heteroatom content can be 15% by mass.

A plastic liquefaction oil may in particular comprise one or more of the following heteroatom contents: from 0 to 8% m of oxygen (measured according to the ASTM D5622 standard), from 1 to 13,000 ppm of nitrogen (measured according to the ASTM standard D4629), from 2 to 10,000 ppm of sulfur (measured according to ISO 20846), from 1 to 10,000 ppm of metals (measured by ICP), from 50 to 6,000 ppm of 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).

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) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). This additional step can make it possible to remove some of the impurities contained in the composition such as oxygen, nitrogen, chlorine, sulfur or other heteroatoms. In particular, reducing the quantity of oxygen can make it possible to avoid the formation of solids and/or gels during step (c1).

During the additional washing step (ii), the polar solvent or water/composition volume ratio can 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.

When water is used for washing (ii), it can have an acidic, basic or neutral pH. An acidic pH can be obtained by adding one or more organic or inorganic acids. Examples of usable organic acids include citric acid (CeHsO?), formic acid (CH ₂ O ₂ ), acetic acid (CH ₃ COOH). 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 obtained by the addition of alkali and alkaline earth metal oxides, alkali and alkaline earth metal hydroxides (e.g., NaOH, KOH, Ca(OH)2), alkali metal bicarbonates and alkaline earth and amines (e.g. triethylamine, ethylenediamine, ammonia).

When water is used for washing, provision may be made to return all or part of the water recovered at the end of washing to step (c1). And optionally, when step c1) is carried out with water, the water recovered at the end of the washing of step c1) can be returned in whole or in part to this washing step (ii) .

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

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

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

As an example, we could consider that the polar solvent (or a mixture of polar solvents where appropriate) is 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 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 a temperature of 20°C.

In particular, this recovery rate can be determined by following the following procedure:

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,

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

Insert a magnetic bar, close the balloon with a polypropylene cap,

Stir the mixture on a mechanical stirring plate at a speed of 500 rpm for 5 min,

At the end of 5 minutes, stop stirring, remove the magnetic bar using a magnetic rod,

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. We consider that complete demixing is reached when the volumes of the two phases no longer vary.

Acceptable immiscible polar solvents include (i) sulfur compounds, e.g. dimethyl sulfoxide, (ii) nitrogen compounds, e.g. N,N-dimethylformamide, (iii) halogenated compounds, e.g. dichloromethane or chloroform, (iv) ethylene glycol, or alternatively: glycol ethers, including in particular polyethylene glycol of chemical formula HO-(CH2-CH2-O)nH with a mass average molar mass of 90 to 800g/mol, for example example diethylene glycol and tetraethylene glycol, polypropylene glycol of chemical formula H[OCH(CH3)CH2]nOH with a mass average molar mass of 130 to 800g/mol, for example dipropylene glycol and tetrapropylene glycol, dialkyl formamides , in which the alkyl group may comprise from 1 to 8 or from 1 to 3 carbon atoms, in particular dimethyl formamide (DMF), dialkyl sulfoxides, in which the alkyl group may comprise from 1 to 8 or from 1 to 3 atoms of carbons, in particular dimethyl sulfoxide (DMSO) and sulfolane, compounds comprising a furan ring, cyclic carbonate esters, comprising in particular from 3 to 8 or from 3 to 4 carbon atoms, in particular propylene carbonate and carbon dioxide ethylene. One or more of the aforementioned solvents may be used. However, advantageously, only one of the aforementioned solvents can be used provided that it is immiscible with the composition containing a liquefaction oil to be purified.

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 800 g/mol or polypropylene glycol of chemical formula H[OCH(CH3)CH2]nOH with a mass-average molar mass of 130 to 800g/mol, or a compound comprising a furan ring, or a cyclic carbonate ester, in particular propylene carbonate or ethylene, alone or in a mixture, preferably alone.

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

Detailed description of step b)

Step b) is a step of treating the composition provided in step a) in the presence of a basic compound at a temperature of at most 450°C to obtain an effluent comprising a treated composition.

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

Step b) is carried out in the presence of a basic compound, preferably a basic nucleophilic compound.

Advantageously, the quantity of basic compound used is 0.1 to 50% m, preferably at least 0.5% m, more preferably at least 1% m, preferably at least 3%. m, even more preferably at least 5% m or even at least 10% m relative to the total mass of the treated composition (composition provided by step (a)).

Advantageously, the quantity of basic compound used can be from 0.1 to 15% m, more preferably from 0.5 to 15% m, more preferably from 1 to 15% m, in particular from 3 to 15% m, or even 5 to 15% m or 10 to 15% m relative to the total mass of the treated composition (composition provided by step a)), or in any interval defined by two of the previous limits.

The basic compound can be added to the composition provided by step a) either before step b) or during step b). This addition of the basic compound to the composition can optionally be followed by a mixing step before carrying out step b). The basic compound can be added to the composition in solid form or dissolved in an aqueous medium, preferably water, or in a solvent, miscible or immiscible with said composition, preferably immiscible.

When the basic compound is dissolved in a solvent or in water, those skilled in the art will then choose a quantity of solvent or water sufficient to dissolve/solubilize it, preferably a quantity of solvent or water as low possible, or just sufficient to saturate the solvent or water with the basic compound.

The ratio by volume of solvent/water containing the basic compound/organic phase, i.e. the ratio by volume of the mixture (basic compound + solvent or water)/organic phase, could 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.

Advantageously, the basic compound added in step b) is in solution in water or in a solvent, and the basic compound content of the water or the solvent is from 0.1 to 50% m, preferably from 15 to 50% m, more preferably 25% to 50% m, preferably 40 to 50% m, even more preferably the water or the solvent is saturated with basic compound, in particular water or Solvent contains just enough basic compound to obtain a saturated solution.

Advantageously, the basic compound added in step b) is in solution in water. Thus, during step b), the organic phase can 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 solution, in particular an aqueous solution, saturated with basic compound could advantageously be used. In particular, step b) can be carried out without adding any solvent other than water or a solvent possibly already present in the composition.

A usable miscible solvent 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.

A usable immiscible solvent may be an immiscible polar solvent, for example those cited for the optional pre-treatment step.

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 an quaternary ammonium cation, for example a cation of tetramethylammonium (TMA+), tetraethylammonium (TEA+), tetrapropylammonium (TPA+), tetrabutylammonium (TBA+). Preferably, the basic compound can comprise an oxide, hydroxide or bicarbonate of an alkali metal cation or an alkaline earth metal cation, or a hydroxide or bicarbonate of a quaternary ammonium cation. More preferably, the basic compound may comprise a aforementioned oxide or hydroxide, alone or in a mixture.

In a preferred embodiment, the basic compound can be chosen from LiOH, NaOH, CsOH, Ba(OH) ₂ , Na ₂ O, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , EtONa, MeONa, NH ₄ OH, TEAOH, TBuOH, TMAOH, and their mixtures or from LiOH, NaOH, CsOH, Ba(OH) ₂ , Na ₂ O, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , NH ₄ OH, TEAOH, TBuOH, TMAOH, and mixtures thereof. A preferred basic compound can be chosen from NaOH, KOH and mixtures thereof, preferably in solution in water or in a solvent, in particular a solvent immiscible with the composition.

The solvent used to solubilize the basic compound may be water, an alcohol, for example methanol or ethanol, or any other organic solvent making it possible to solubilize the chosen basic compound, preferably water or a solvent immiscible with the composition.

In a preferred embodiment, prior to step b) or during step b), it is possible to add to the composition of step a) (i) a solid basic compound, (ii) a basic compound previously dissolved in an aqueous medium, preferably water, or (iii) a basic compound previously dissolved in a solvent, preferably a polar solvent immiscible with said composition, the basic compound content of the water or the solvent being from 15 to 50% by mass, preferably from 25% to 50%m, preferably from 40 to 50%m. This embodiment can in particular be combined with the temperature conditions and other operating conditions described below. This embodiment can also be combined with the particularly preferred embodiment described below.

Step b) can be carried out at a temperature of at most 450°C. In one embodiment, step b) can be carried out at a temperature of 50 to 450 °C, preferably 50 to 350 °C, more preferably 50 to 250 °C, even more preferably 50 at 225°C, 50 to 200°C, 70 to 190°C or 80 to 185°C, or in any range defined by any two of these limits.

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

In a particularly preferred embodiment, step b) is carried out for a duration 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 20 minutes. 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, 190°C or 185°C. In this particularly preferred embodiment, step b) 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 particular embodiment preferred, step b) can be carried out at an absolute pressure of 0.1 to 100 bars, preferably of 1 to 50 bars.

In this particularly preferred embodiment, the composition provided by step a) can advantageously be brought into contact with:

- 0.1 to 15% m of a basic compound, advantageously comprising an alkali or alkaline earth metal cation, and preferably in the presence of water, preferably with 0.5 to 15% m of a basic compound , more preferably with 1 to 10% m of a basic compound (weight percentages of basic compound relative to the composition), and/or

- with water containing 15 to 50% m of basic compound, preferably 25% to 50% m, more preferably 40 to 50% m (mass percentages of basic compound relative to water), even more preferably with water saturated with basic compound.

A preferred strong base can be chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2Û, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , TMAOH, TEAOH, TBuOH, EtONa, MeONa and their mixtures. A more preferred strong base may be chosen from LiOH, NaOH, CsOH, Ba(OH) ₂ , Na ₂ O, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , TMAOH, TEAOH , TBuOH, and their mixtures, and in particular among NaOH, KOH and their mixtures, in particular for the implementation of the particularly preferred embodiment.

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

Detailed description of the optional additional solids separation step

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

During step c), the effluent from step b) can be subjected to (c1) washing with water or a solvent immiscible with the modified composition, (c2) separation, or to succession of steps (c2) and (c1). This step c) makes it possible to recover a purified composition having a reduced heteroatom content and a phase (solid or liquid) containing the compound. basic and heteroatoms initially contained in the modified composition. This step thus makes it possible to separate the impurities from the composition.

The choice of steps (c1), (c2) or (c2) + (c1) depends in particular on the nature of the basic compound and the desired purification objective. For example, we can distinguish cases (A), (B) and (C) below:

(A) the basic compound is added to the composition of step a) in the form of a solid basic compound, step c) can then comprise:

(A1) the washing step (c1) which makes it possible to recover a phase containing the purified composition and a phase containing the basic compound, the impurities, and the water or the solvent used for washing, or

(A2) the separation step (c2), typically a solid-liquid extraction, which makes it possible to separate a solid phase comprising the basic compound and the impurities having precipitated and a liquid phase containing the purified composition, or

(A3) the separation step (c2) described above followed by a washing step (c1) of the liquid phase containing the purified composition recovered at the outlet of step (c2),

(B) the basic compound is added to the composition of step a) dissolved in a solvent miscible with the composition, step c) can then comprise the washing step (c1) which makes it possible to recover a phase containing the purified composition and a phase containing the miscible solvent, the solubilized basic compound, the impurities, and the water or the immiscible solvent used for washing;

(C) the basic compound is added to the composition of step a) dissolved in an aqueous medium or in a solvent immiscible with the composition, step c) can then comprise:

(C1) the washing step (c1) which makes it possible to recover a phase containing the purified composition and a phase containing the basic compound, the impurities, the water or the solvent used for washing and the aqueous medium or the solvent not miscible used to add the basic compound, or

(C2) the separation step (c2), typically a liquid-liquid separation, which makes it possible to separate the phase containing the purified composition and a phase containing the water or the immiscible solvent, the basic compound and the impurities, or

(C3) the separation step (c2) described above followed by a washing step (c1) of the phase containing the purified composition recovered at the outlet of step (c2).

When step c) implements the separation (c2), namely in the cases (A2), (A3), (C2) and (C3), we can advantageously recover the phase containing the basic compound recovered at the outlet of the separation step (c2) and return it in whole or in part to the step b) treatment. This makes it possible to reduce the quantities of basic compound to be used and thus reduce the associated costs.

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

This step (c1) makes it possible to eliminate the impurities containing heteroatoms present in the first effluent containing the modified composition leaving step b) by solubilizing them in a solvent (water or an organic solvent).

This washing step (c1) can also make it possible to separate the basic compound from the purified composition. The washing step (c1) is thus particularly advantageous when the basic compound used during step b) is added to the composition in solid form or dissolved in a solvent miscible with the composition to be treated, but can also be put into work when the basic compound is in solution in a solvent (water or organic solvent) immiscible with the composition to be treated.

When the basic compound used in step b) is solid or solubilized in water or a solvent immiscible with the composition, this washing step (c1) can be omitted or carried out after the separation step (c2 ), as explained below.

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

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

An acidic pH can be obtained by adding one or more organic or inorganic acids. Examples are cited with reference to washing (ii) of the optional pre-treatment step. Preferably, the water can have a pH of 0.1 to 6.9.

A basic pH can be obtained by adding a basic compound, for example those mentioned above with reference to washing (ii) of the optional pre-treatment step or those used in step b). Preferably, the water can have a pH of 7.1 to 14.

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

Step (c1) can 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 even in any interval defined by any two of these limits, advantageously without external heating. Step (c1) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step b) is carried out.

Step (c1) can be implemented on the first effluent directly from step b), without an intermediate step, or on the effluent containing the purified composition leaving step (c2). When it follows step (c2), washing step (c1) then makes it possible to eliminate any residue of the basic compound and/or impurities containing heteroatoms, still present in the purified composition leaving the step (c2), which can make it possible to obtain a purified composition having in particular a chlorine content less than or equal to 30 ppm (by mass) and a sodium content less than or equal to 2 ppm (by mass).

During step (c1), the solvent or water/effluent volume ratio containing the purified composition can 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.

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

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

The washing step (c1) can be carried out continuously or in batches.

Detailed description of the separation step (c2)

The separation step (c2) also makes it possible to separate the purified composition to obtain a phase containing the purified composition having a reduced heteroatom content, and a phase containing the basic compound and the impurities. It could be a separation liquid/liquid or a solid/liquid separation. It can advantageously be carried out by (I) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or three of these steps.

Step (c2) can be carried out directly on the effluent containing the modified composition of step b). In this case, it makes it possible to separate the purified composition from the basic compound, in particular when the latter has been added in solid form or in a solvent immiscible with the composition (water or immiscible organic solvent). This step (c2) then separates a phase containing the purified composition and a phase containing the basic compound and the impurities, and, where appropriate, the water or the solvent immiscible with the composition. This phase containing the basic compound can then be returned to step b) to reuse the basic compound. This makes it possible to reduce the quantity of total basic compound consumed in step b).

Prior to step (c2), the effluent containing the modified composition leaving step b) can be treated in at least one mechanical or electrostatic coalescer in order to break the possible emulsion and concentrate the basic compound in the solvent or water.

Step (c2) can 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 even in any interval defined by any two of these limits, advantageously without external heating. Step (c2) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step b) is carried out.

Detailed description of the optional catalytic hydrotreatment step

Upstream of gasification step e), advantageously upstream of optional distillation step d), preferably downstream of the optional solids separation step when present, the effluent containing the purified composition can be subjected to single-step or two-step hydrotreatment.

When this hydrotreatment is carried out in a single step, the effluent 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 from 30 to 100 bars and in the presence of a hydrotreatment catalyst, for example a NiMo (0.1-60% by mass) and/or CoMo (0.1-60% by mass) type catalyst generally on a support.

Alternatively, the hydrotreatment can be carried out in a first step (1) in which the effluent 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 wt%) and/or Ni (0.1-60 wt%) and/or NiMo (0.1-60% by weight), and in a second step (d-2) in which the effluent from step (d-1) is hydrotreated at a temperature of 200 to 450 ° C, preferably from 250 to 340 °C in the presence of hydrogen at an absolute pressure of 20 to 150 bars, preferably from 30 to 100 bars and in the presence of a second hydrotreatment catalyst, for example a catalyst of the type NiMo (0.1-60 wt%) and/or CoMo (0.1-60 wt%). The first step can then make it possible to hydrogenate dienes initially present in the composition.

This hydrotreatment step can be carried out in a single reactor with several catalytic beds placed in series with possibly additional hydrogen between the beds or in several reactors in series depending on the desired objective.

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

Preferably, the feed for the hydrotreatment, containing at least part of the purified composition, can be diluted with part of the hydrotreatment effluent, still having a temperature higher than the desired temperature at the inlet of the hydrotreatment. 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 charge.

Preferably, the part of the hydrotreatment effluent which is not recycled but still at a high temperature, can exchange its sensible heat with the composition comprising a plastic liquefaction oil and thus ensure the preheating of this composition entering into step b).

The effluent leaving the hydrotreatment step, namely the purified and hydrotreated composition, optionally purified by passing over a solid adsorbent, can be washed with water to eliminate inorganic compounds such as hydrosulfide, hydrochloride. hydrogen and ammonia before being subjected to subsequent treatments.

The second effluent from step c) or the effluent from the hydrotreatment step can 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 water content.

The adsorbent can 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 their combinations, (vi) an alumina for example an alumina obtained by precipitation of boehmite, 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 example Selexsorb ® from BASF, a promoted alumina acid, 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) a clay treated with an acid such as Tonsil ® from Clariant, (xiii) a molecular sieve in the form of an aluminosilicate containing an alkaline 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.

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 to 10 ^h'1 .

Detailed description of the optional separation step by distillation

The second effluent produced during step c), optionally hydrotreated, purified on an adsorbent and/or washed with water, can be separated d) by distillation into at least two distinct fractions, typically a heavy fraction and a light fraction.

It is then possible to send one of these fractions to gasification step e); advantageously, a heavy fraction or the heaviest fraction is sent to gasification step e).

This separation can in particular be carried out by distillation, in particular by atmospheric distillation or by distillation under reduced pressure.

This can make it possible to separate the second effluent into two or more fractions, the lighter fraction(s) being able for example to be sent to refining units of the steam cracking or other type, and the heavy fraction(s) being sent to step e) .

The second effluent produced during step c), optionally hydrotreated, purified on an adsorbent and/or washed with water, can in particular be split into usable flows whose cutting points are typically chosen according to the treatment ulterior. This fractionation can be carried out according to distillation temperature ranges, for example to separate flows such as LPG, gasoline, diesel, heavy fuel oil, kerosene, which can then be treated in a gasifier and/or 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. Those skilled in the art know how to select the cuts most suited to subsequent processing units depending on the desired objective.

In particular, fractions 350 ⁺ °C or 375 ⁺ °C will advantageously be sent to gasification step e). The fractions 350 ⁺ °C, respectively 375+ °C correspond to fractions whose initial boiling point is greater than or equal to 350 °C, respectively 375 °C.

The second effluent from step c), optionally after solid/liquid separation and/or hydrotreatment, or one of the fractions from step d), can be submitted, alone or mixed with another hydrocarbon feedstock, to a gasification process for producing synthesis gas comprising at least dihydrogen, carbon monoxide and carbon dioxide.

The other hydrocarbon load comes from the processing of crude oil. This hydrocarbon load generally corresponds to a cut of 350 ⁺ °C or 375 ⁺ °C. It is typically a visbroken residue, a VGO (vacuum gas oil), a residue from an atmospheric distillation, a residue from a vacuum distillation, a residue from a distillation under visco-reduced vacuum, alone or in a mixture.

Depending on the initial heteroatom contents of the plastic liquefaction oil, the second effluent from step c), optionally after solid/liquid separation and/or hydrotreatment, or one of the fractions from step d) , can be subjected to the gasification step mixed with other conventional charges of petroleum origin, in particular depending on the volumes available and/or so that the heteroatom content of the charge entering the gasification step has a content in heteroatoms conforming to the required requirements. The charge for the gasification stage may in particular contain up to 100% by mass, 90% by mass, 80% by mass, 70% by mass, 60% by mass, 50% by mass, 40% by mass, 30 % by mass, 20% by mass, 15% by mass, 10% by mass or 5% by mass of the second effluent from step c), optionally after solid/liquid separation and/or hydrotreatment, or one of the fractions of step d), or in any interval defined by two of these limits.

This gasification step may be a partial oxidation gasification step implemented in a partial oxidation gasification unit to produce a synthesis gas comprising at least dihydrogen, carbon monoxide and carbon dioxide.

The second effluent from step c) or one of the fractions from step d) can, before step e), be mixed with another hydrocarbon feedstock such as naphtha, diesel or any refining product of the crude oil to have a concentration of purified composition ranging from 0.01%m to at most 90%m, preferably from 0.1%m to 75%m, even more preferably from 1%m to 50%m or in any of these limits.

In this document, the term "partial oxidation gasification (PCX) unit or installation" or "PCX gasification plant" means a facility that includes all equipment, lines and controls necessary to carry out PCX gasification of waste liquefied plastics. For example, the gasification plant can include a gasifier, a feed injector, a gasifier ball mill, a feed pulverization unit and/or a solidification tank.

As used herein, the term "partial oxidation" refers to the high temperature conversion of a carbon-containing feedstock to syngas (carbon monoxide, hydrogen, and carbon dioxide), where the conversion is carried out with an amount of oxygen that is less than the stoichiometric amount of oxygen necessary for the complete oxidation of carbon to CO2. Reactions that occur in a partial oxidation (POX) gasifier include the conversion of a carbon-containing feedstock to syngas, and specific examples of reactions include, but are not limited to, partial oxidation, displacement from gas to water (Water Gas shift) - primary reactions, the Boudouard oxidation reaction, methanation, hydrogen reforming, steam reforming and carbon dioxide reforming.

The present technology is generally directed towards a process for producing synthesis gas (syngas) from a plastic liquefaction oil composition. The process generally includes introducing the plastic liquefaction oil composition and an oxidizing agent comprising molecular oxygen (O2) into a POX gasifier and performing a partial oxidation reaction in the gasifier by reacting at least part of the plastic liquefaction oil and at least part of the molecular oxygen. The plastic liquefaction oil composition may be in a solid or liquid form before being introduced into the POX gasifier.

The POX gasification installation comprises at least one POX gasification reactor or gasifier. In one embodiment or in combination with any of the mentioned embodiments, the POX gasification unit may comprise a liquid-fed gasifier or a solid-fed gasifier. More particularly, in various embodiments, the POX gasification unit may perform liquid-fed POX gasification. As used herein, the term "liquid-fed POX gasification" means a POX gasification process in which the process feed comprises primarily liquid components at 25°C and 1 atm. Additionally, or alternatively, in various embodiments, the POX gasification unit may perform solid-state POX gasification. The term "solid-state POX gasification" means a POX gasification process in which the process feed primarily comprises components that are solid at 25°C and 1 atm. Liquid- and solid-fed POX gasification processes can be co-fed with lesser amounts of other components having a different phase at 25 °C and 1 atm. Thus, solid-fed POX gasifiers can be co-fed with liquids, but only in quantities (by mass) less than the amount of solids fed into the solid-fed POX gasifier. In one embodiment or in combination with any of the mentioned embodiments, the total feed to a liquid-fed POX gasifier may include at least 60, or at least 70, or at least 80, or at least 90, or at least 95% by mass of components that are liquid at 25°C and 1 atm; and the total feed to a solids-fed POX gasifier may include at least 60, or at least 70, or at least 80, or at least 90, or at least 95% by mass of components that are solid at 25°C and 1 atm.

In one embodiment or in combination with any embodiment mentioned herein, the oxidizing agent comprises an oxidizing gas which may include air, oxygen-enriched air, or molecular oxygen (O2), or steam.

Gasification by partial oxidation can be carried out in the presence or absence of a catalyst. Suitable catalysts include one or more metallic components of groups 8 to 10 of the periodic table, such as platinum, palladium, rhodium, iridium, osmium, ruthenium, and optionally, one or more elements of groups 5 to 7, 11, such as iron, cobalt, nickel, copper, vanadium and chromium, these elements typically being supported on a support such as zirconia, alumina, CeC>2, Y2O3 or TiG>2-

In one embodiment or in combination with any embodiment mentioned herein, the gasification zone, and optionally all reaction zones in the gasifier/gasification reactor, may operate at a temperature of at least 1000°C , at least 1100 °C, at least 1200 °C, at least 1250 °C, or at least 1300 °C and/or not more than 2500 °C, not more than 2000 °C, not more than 1800 °C, or not more than 1600°C. The reaction temperature can be autogenous. Advantageously, the gasifier operating in steady state can be at an autogenous temperature and does not require the application of external energy sources to heat the gasification zone.

In one embodiment or in combination with any embodiment mentioned herein, the gasifier can operate at a pressure inside the gasification zone (or combustion chamber) of at least 1.3 MPa to 9 MPa, examples of suitable pressure ranges include 2 to 7 MPa, 2 to 6 MPa, 2.5 to 7 MPa, 2 to 5.5 MPa, 3 to 5 MPa or any range defined by one of the limits of these beaches.

In general, the average residence time of gases in the gasification reactor can be very short to increase the throughput. Because the gasifier can operate at high temperature and pressure, virtually complete conversion of the feedstock to gas can occur in a very short time. In one embodiment or in combination with any embodiment mentioned herein, the average residence time of the gases in the gasifier may be not more than 30, not more than 25, not more than 20, not more than 15, not more than 10, or not more than 7 seconds.

Generally, the raw syngas stream discharged from the gasification reactor includes gases such as hydrogen, carbon monoxide and carbon dioxide and may include other gases such as methane, hydrogen sulfide and nitrogen depending on the fuel source and gasification conditions. Description of figures

Figure 1 describes a possible embodiment of the invention. In this possible embodiment, the composition comprising a plastic liquefaction oil (1) is first optionally pretreated in the pretreatment section (A) to be subjected to pretreatment (PTT) by (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv). The composition (1) or the pretreated composition

(2) is then sent to a treatment section (B) in the presence of a basic compound

(3) implementing step b) of the invention. The first effluent (4) leaving step b) and containing the modified composition can then be sent to an optional solids separation section (S1). The effluent (5) leaving the section (S1) or the first effluent (4) leaving the section (B) is then sent to a separation section (C) implementing step c) of the present invention , consisting of the washing step (c1), the separation step (c2) or the succession of steps (c2) and (c1). When this section (C) implements step (c2), the separated phase (7) containing the basic compound can be returned to the treatment section (B). The second effluent (6) leaving the section (C) and containing the purified composition having a reduced heteroatom content, can then be sent to an optional solid separation section (S2) or to an optional hydrotreatment section (HDT) or to an optional distillation section (D). Thus, the effluent (7) from the optional solid separation section (S2) or the effluent (8) from the optional hydrotreatment section (HDT) can be sent to the optional distillation section (D) to put into process carries out step d) and be separated into at least two fractions (9a) and (9b). One of the two fractions, preferably the heaviest fraction (9b), is then sent to the gasification unit (E) to carry out step e) and obtain a synthesis gas (10). Alternatively or in combination, the effluent (6) from section (C), the effluent (7) from the optional solid separation section (S2) or the effluent (8) from section (HDT) can be sent directly to the gasification section (E).

In a particularly advantageous embodiment, the installation comprises sections (B), (S1), (C), (D) and (E).

Examples

The embodiments of the present invention are illustrated by the following non-limiting examples.

Example 1: Purification of a plastic pyrolysis oil in the presence of a strong base and water followed by washing with water

The physicochemical characteristics of the plastic pyrolysis oil used are described in Table 1, below. This product is a good representation of the general quality of plastic pyrolysis oils, although the chlorine content is not very high. Table 1

Test protocol:

A 1.5 L AISI-316L grade stainless steel autoclave equipped with mechanical stirring is loaded with HPP4 pyrolysis oil, a strong base in the form of NaOH and water, the strong base being solubilized in water before its introduction into the autoclave (table 2). The sum of the volume of pyrolysis oil and the volume of water introduced is approximately 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 sky in the autoclave is flushed with nitrogen for 30 minutes. The autoclave is then heated under autogenous pressure with stirring at a speed of 400 to 1500 rpm at a temperature of 225°C for a period of 30 minutes, once the target temperature has been reached. The temperature rise speed is set at 30°C/10 minutes.

Table 2

At the end of the reaction, the autoclave is cooled to room temperature then the mixture is unloaded and washed three times with water with, at each wash, a water/charge volume ratio = 40/60, for remove strong base residue and water-soluble impurities. The resulting purified and washed pyrolysis oil is analyzed to measure the content of residual impurities (Table 3).

Table 3

The data in Table 3 show that the use of soda in the presence of water followed by washing makes it possible to significantly reduce the impurities initially contained in the pyrolysis oil as well as the sodium introduced by the soda treatment. The pyrolysis oil can then either be used as is, or optionally be dried on an adsorbent such as a molecular sieve or an anhydrous salt, for example Na2SO4, then is distilled under reduced pressure in order to eliminate any possible trace of solid, for example strong base, adsorbent residue, anhydrous/hydrated salt or gums.

Example 2: Mixture of the product from Example 1 with a petroleum product We consider a WR (Visbroken Vacuum Residue) type petroleum product having the following characteristics (table 4):

Table 4

We consider the mixtures below of said WR with the product of example 1 (treated HPP4) or with the initial untreated HPP4 (HPP4), depending on their silicon and chlorine levels (table 5). The mixtures are expressed as a mass percentage of HPP4, treated or not. The “Gasifier specification and downstream units” column corresponds to the maximum admissible values of silicon and chlorine levels in a product, before injection into a gasifier.

Table 5

In this example, the treatment process according to the invention of the HPP4 oil thus makes it possible to introduce it at a level of 10% by mass into a mixture with the WR, while satisfying the requirements required for the gasification stage and its downstream units. Depending on the heteroatom contents of the plastic liquefaction oil treated or depending on the volumes obtained, we could consider treating it in a gasification stage alone or in mixture with other conventional fillers of petroleum origin.

Claims

1. Process for treating by gasification a composition comprising a plastic liquefaction oil, comprising the following steps: a) providing a composition comprising a plastic liquefaction oil containing at least 20 ppm by weight of heteroatoms, b) bringing into contact the composition supplied in step a) with a basic compound at a temperature of at most 450 °C to obtain a first effluent containing a modified composition, c) subjecting the first effluent from step b) to (c1) a washing with water or a solvent immiscible with the modified composition, (c2) separation, or in succession of steps (c2) and (c1), and obtaining a second effluent containing a purified composition having a reduced content of heteroatoms, and a phase containing the basic compound and heteroatoms initially contained in the modified composition, d) optionally, the second effluent from step c) is separated by distillation into at least two distinct fractions, e) subjecting the second effluent to step c) or one of the fractions of step d), alone or mixed with another hydrocarbon feed, to a gasification process to produce synthesis gas comprising at least dihydrogen, carbon monoxide and carbon dioxide, and in which

- prior to step b) or during step b), (i) a solid basic compound is added to the composition of step a), (ii) a basic compound previously dissolved in an aqueous medium, preferably water, or (iii) a basic compound previously dissolved in a polar solvent immiscible with said composition, the basic compound content of the water or the solvent being 15 to 50% by mass.

2. Method according to claim 1, in which step b) is carried out in the presence of 0.1 to 50% m of basic compound relative to the total mass of the treated composition.

3. Method according to any one of claims 1 or 2, in which step b) is characterized in that the basic compound comprises an oxide, a hydroxide, a bicarbonate or an alkoxide of an alkali metal cation or d an alkaline earth metal cation, or a hydroxide or bicarbonate of a quaternary ammonium cation, alone or in a mixture.

4. Method according to any one of claims 1 to 3, in which step b) is characterized in that the basic compound is chosen from LiOH, NaOH, CsOH, Ba(OH) ₂ , Na ₂ O, KOH, K ₂ O, CaO, Ca(OH) ₂ , MgO, Mg(OH) ₂ , NH ₄ OH, TMAOH, TEAOH, TBuOH, MeONA, EtONa and their mixtures.

5. Method according to any one of claims 1 to 4, characterized in that step b) comprises one or more of the following characteristics:

- step b) is carried out at a temperature of 50 to 450 °C, preferably 50 to 350 °C, more preferably 50 to 250 °C, more preferably 50 to

225°C, 50 to 200°C, 70 to 190°C or 80 to 185°C,

- step b) is carried out for a duration of 0.1 second to 3 hours, preferably 0.1 second to 2 hours, more preferably 1 minute to 1 hour, 1 minute to 20 minutes or 1 minute to 16 minutes.

6. Method according to any one of claims 1 to 5, in which, prior to the treatment of step b), said composition provided by step a) is subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv).

7. Method according to any one of claims 1 to 6, characterized in that step c) is preceded or followed by a step of separating the solids by (i) filtration, (ii) centrifugation, (iii) hydrocyclone or (iv) a combination of two or three of these steps.

8. Method according to any one of claims 1 to 7, characterized in that step c) is followed, optionally before optional step d) of separation, by one or more of the following treatments (i) a treatment purification 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 water content, (ii) one- or two-step catalytic hydrotreatment to provide a purified hydrotreated composition.

9. Method according to any one of claims 1 to 8, characterized in that step c) comprises at least the separation step (c2) to separate the phase containing the basic compound and heteroatoms, and the purified composition , and in that the phase containing the basic compound and heteroatoms is returned in whole or in part to step b).

10. Method according to any one of claims 1 to 9, characterized in that step c1) is carried out in the presence of water at neutral, basic or acidic pH. Process according to any one of claims 1 to 10, characterized in that step c2) is carried out by (i) centrifugation, (ii) decantation, (iii) hydrocyclone or (iv) by the combination of two or three of these steps. Process according to any one of claims 1 to 11, in which the synthesis gas produced in step e) is (i) treated in a purification unit, (ii) treated in a Fischer-Tropsch process, (iii) ) used as fuel, and/or (iv) used in an alcohol production unit by fermentation or catalytic process.