Method for purifying a plastic liquefaction oil composition by hydrotreating and basic treatment

Abstract

The invention relates to a method for purifying a composition (1) comprising a plastic liquefaction oil comprising a first step of mild hydrotreating (HDT1), followed by a treatment step (TTbase) in the presence of a basic compound at a temperature of at most 350°C. This effluent (5) is then subjected to at least one step chosen from (c1) a washing with water or a solvent immiscible with the effluent and (c2) a separation. The effluent (6) thus purified can optionally be sent to a second hydrotreating step at higher temperature (HDT2), used as is or sent to another subsequent treatment.

Description

[0001] TITLE: Process for purifying a plastic liquefaction oil composition by hydrotreatment and basic treatment

[0002] Technical field of the invention

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

[0004] 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 it through pyrolysis or hydrothermal liquefaction. However, the resulting plastic oil typically contains large amounts of dienes and heteroatoms, including metals. These numerous heteroatoms, including metals, are contaminants for the catalysts in the hydrotreatment processes typically used to recycle plastics. Furthermore, dienes readily react to form gums. Dienes are also precursors to coke in a steam cracker. Therefore, plastic liquefaction oils must be treated for recycling.

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

[0008] Some of these involve heating the plastic oil in the presence of a basic compound, usually in aqueous solution.

[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 feedstock which is optionally washed with an acid solution before introduction into the steam cracker. 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 includes a heat treatment of the feed 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 feed, followed by hydrotreatment in order to obtain a further reduction of at least 50% of the chlorine content.

[0011] Patent application WO2021 / 105326 claims a method for recovering 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.

[0012] Most existing purification treatments are carried out at relatively high temperatures and cause the formation of gums which can clog the installations used.

[0013] There is therefore a need to improve existing purification processes.

[0014] Summary of the invention

[0015] The invention aims to propose a process for purifying plastic liquefaction oil making it possible to limit the formation of gums and the clogging of installations.

[0016] For this purpose, the invention provides a method for purifying a composition comprising a plastic liquefaction oil comprising the following steps:

[0017] (a) providing a composition comprising a plastic liquefaction oil, said composition containing at least 20 ppm by mass of heteroatoms, a diene number of at least 0.5 g I2 / 100 g measured according to UOP 326 and a bromine number of at least 5 g Br2 / 100 g measured according to ASTM D1159,

[0018] (b) subjecting the composition of step (a) to a first hydrotreatment step to obtain a hydrotreated composition forming a first effluent having a reduced diene index, the first hydrotreatment step being carried out at a temperature of at most 250°C in the presence of dihydrogen and at least one hydrotreatment catalyst,

[0019] (c) contacting the first effluent with a basic compound at a temperature of at most 350°C to obtain a modified hydrotreated composition forming a second effluent,

[0020] (d) subjecting the second effluent to at least one step selected from (d1) washing with water or a solvent immiscible with the second effluent, and (d2) separation by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation, (v) distillation or (vi) a combination of two or more of these steps, and separately recovering a purified composition forming a third effluent having a reduced heteroatom content, and a phase containing the basic compound and heteroatoms initially contained in the second effluent,

[0021] (f) optionally subjecting the third effluent to a second hydrotreatment step to obtain a fourth effluent, the second hydrotreatment step being carried out at a temperature of at least 200°C in the presence of dihydrogen and at least one hydrotreatment catalyst.

[0022] The sequence of steps of the process according to the invention makes it possible to purify the composition to be treated, and in particular to eliminate heteroatoms and in particular silicon, while avoiding the formation of gums. In particular, the first hydrotreatment step, carried out in particular without prior purification of the composition or without any treatment other than separation of the solids, in particular fines, can be carried out without deactivation of the catalyst and allows the basic treatment to be carried out at a high temperature, in particular at least 180°C or 200°C, without the formation of gums.

[0023] Said composition provided in step (a) of the method according to the invention may comprise at least one of the following characteristics: said composition contains at least 10% by weight of plastic liquefaction oil, the other part of said composition being a diluent or said composition contains only plastic liquefaction oil, said plastic liquefaction oil in said composition has an initial boiling point of at least 15°C and a final boiling point of at most 700°C, preferably at most 600°C, more preferably 560°C, preferably 450°C, more preferably 350°C, preferably 250°C, said plastic liquefaction oil has a diene number of at most 50 gl2 / 100 g, preferably at most 25 gl2 / 100 g, more preferably at most 10 gl2 / 100 g, measured according to UOP 326, said plastic liquefaction oil contains more than 2 ppm by weight of metals,said plastic liquefaction oil contains at least 5 ppm by weight of Si, preferably at most 5000 ppm by weight of Si, and / or at least 1 ppm by weight of Si, preferably at most 5000 ppm by weight of Si, and / or at least 1 ppm by weight of Si, preferably at most 1000 ppm by weight of Si, and / or at least 1 ppm by weight of Cl, preferably at most 5000 ppm by weight, and / or at least 1 ppm by weight of P, preferably at most 5000 ppm by weight relative to the total weight of said plastic liquefaction oil.,

[0024] Step (b) according to the invention may comprise one or more of the following features: prior to step (b), the composition provided in step (a) is subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, (v) a hydrocyclone or (vi) the combination of at least two steps (i) to (iv), the inlet temperature is 25 to 250°C, preferably 130 to 250°C, the absolute pressure is 5 to 90 bar, preferably 10-50, more preferably 25-50 bar, in the presence of H2 and / or the molar ratio of H2 to the total molar sum of alkynes and dienes in said composition is at least 1.5, preferably at least 2, preferably at least 3, at least plus 15, said first hydrotreatment step comprises one or more catalytic beds with, preferably, an overall temperature increase of at most 150°C, preferably at most 100°C,and / or an increase in temperature of at most 100°C, preferably at most 50°C for each catalytic bed, preferably with an intermediate quench between said catalytic beds, said quenching preferably being carried out with H2 or with the fourth effluent recovered in step (f); this first step is carried out in a fixed bed reactor, preferably in the presence of at least one catalyst comprising at least one metal from groups 8-10, preferably chosen from the group Pt, Pd, Ni and / or their mixture on a support such as alumina, titanium, silica, zirconia, magnesia, carbon and / or their mixtures; preferably, this catalyst is a Ni-based catalyst passivated after its reduction preferably using a di-alkyl-sulfide such as DiMethylSulfide (DMS) or DiMethylDiSulfide (DMDS) or DiEthylSulfide (DES), or thiophenic compounds; this first step is carried out in a fixed bed reactor,preferably in the presence of at least one catalyst comprising at least one metal from group 6, such as for example Mo, W, in combination or not with a promoter chosen from at least one metal from groups 8-10, such as for example Ni and / or Co, and / or a mixture thereof, these metals being used in sulphurized form and preferably supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof; the first effluent has a diene index of at most 1.5 g 12 / 100 g, preferably at most 1.0 g 12 / 100 g, more preferably at most 0.5 g 12 / 100 g, in said composition, at least 10% by weight, preferably at least 15% by weight, preferably at least 25% by weight, more preferably at least 50% by weight of said composition has a boiling point of at least 150°C relative to the total weight of said composition.,

[0025] Step (c) according to the invention may comprise one or more of the following characteristics: prior to step (c), the first effluent is subjected to flash distillation in order to remove at least part of the gaseous phase that it contains, prior to step c) or during step c), there is added to the first effluent (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, step (c) is carried out in the presence of 0.1 to 50% by weight of basic compound relative to the total mass of said first effluent, 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 is chosen from LiOH, NaOH, CsOH, Ba(OH)2, Na2Û, KOH, K2O, CaO, Ca(OH)2,MgO, Mg(OH)2, NH4OH, TMAOH, TEAOH, TBuOH, MeONa, EtONa and mixtures thereof, step c) is carried out at a temperature of 100 to 350°C, preferably 180 to 300°C, step c) is carried out for a period of 0.1 seconds to 3 hours, preferably 1 minute to 1 hour, more preferably 1 minute to 30 minutes.,

[0026] Step (d) according to the invention may comprise one or more of the following characteristics: step d1) 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 second effluent, preferably in the presence of water, step (d) comprises at least the separation step (d2) to separate the phase containing the basic compound and the third effluent, and optionally the phase containing the basic compound is returned in whole or in part to step (c).

[0027] Advantageously, whatever the embodiment, steps c) and d) can be implemented under conditions in which the treated composition is solely, and entirely, in the liquid phase, throughout the implementation of these steps. In other words, steps c) and d) are then implemented under conditions in which the treated composition does not undergo vaporization. The person skilled in the art will know for this purpose how to choose a suitable temperature depending on the treated composition.

[0028] Advantageously, after step (d), optionally prior to step (f), the third effluent can be (e) 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.

[0029] Step (f) according to the invention may comprise one or more of the following characteristics:

[0030] - After this second hydrotreatment step, the olefin concentration, measured by the bromine index in the fourth effluent, is at most 5.0 gBr2 / 100g, preferably at most 2.0 gBr2 / 100g, preferably at most 1.5 gBr2 / 100g, more preferably at most 0.5 gBr2 / 100g, as measured according to ASTM D1159,

[0031] This second hydrotreatment step comprises one or more catalytic beds with, preferably, an overall increase in temperature of at most 100°C, and / or an increase in temperature of at most 50°C on each catalytic bed, with, preferably, an intermediate quench between said catalytic beds, said quenching preferably being carried out with H2 or with said stream of purified hydrocarbons recovered in step f);

[0032] The inlet temperature is at least 200°C, preferably 230°C, more preferably 250°C and at most 500°C;

[0033] The WH is from 1 to 10h-1, preferably from 2 to 4h-1; the absolute pressure is from 10 to 160 bar in the presence of H2; Said second hydrotreatment step is carried out in the presence of at least one catalyst which comprises at least one metal from group 6 such as for example Mo, W in combination or not with a promoter chosen from at least one metal from groups 8-10 such as for example Ni and / or Co, and / or a mixture thereof, these metals preferably being used in sulphide form and supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof; the H2 / hydrocarbon ratio is from 200 NL / L to 900 NL / L, preferably in the presence of at least 0.005% by weight, preferably 0.05% by weight, more preferably 0.5% by weight of sulfur, preferably H2S or organic sulfur compounds, in the stream;at the top of the second hydrotreatment stage, a silicon trap is present, working at a temperature of at least 200°C, and / or at a WH of 1 to 10h-1, and / or at an absolute pressure of 10 to 160 bar in the presence of H2; optionally with a metal trap working at a temperature of at least 200°C, at a WH of 1 to 10h-1, at an absolute pressure of 10 to 160 bar in the presence of H2.;

[0034] Advantageously, before carrying out the first and / or second hydrotreatment, a dilution may be carried out using a diluent, said diluent preferably being a hydrocarbon stream having a boiling range of 50°C to 150°C or a boiling range of 150°C to 250°C or a boiling range of 200°C to 350°C, or the effluent of said first and / or said second hydrotreatment or any mixture thereof. Preferably, said diluent is added at a concentration of at most 80% by weight, in particular 5 to 80% by weight, preferably at most 50% by weight and, optionally, said diluent is separated at the outlet of said first and / or said second hydrotreatment by distillation, for example by flash distillation, and, preferably, recycled to the inlet of said first and / or said second hydrotreatment.Advantageously, said diluent preferably has a bromine index of at most 5 gBr2 / 100g, in particular from 0.1 to 5 gBr2 / 100g, and / or a diene index of at most 0.5 gBr2 / 100g, in particular from 0.01 to 0.5 gBr2 / 100g, and / or a sulfur content of at most 1000 ppm by weight, in particular from 2 to 1000 ppm.

[0035] Advantageously, the fourth effluent leaving step (f) can further be washed to remove inorganic compounds such as sulfur, chlorine or nitrogen compounds.

[0036] Advantageously, the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, can be used as is 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,

[0037] Advantageously, the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, can be treated, pure or diluted, optionally after separation into usable streams, in a steam cracker to produce olefins, and / or a fluidized bed catalytic cracker, and / or a hydrocracker, then optionally in a steam cracker, and / or a hydrotreatment reactor, in particular a catalytic hydrogenation reactor. Preferably, the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, can be subjected, pure or diluted, optionally after separation into usable streams, to a steam cracking step to produce olefins such as ethylene and propylene, which can then be used to manufacture new polymers by polymerization.

[0038] Advantageously, step a) may comprise: a1) a step of providing a stream of plastic or plastic-containing waste; a2) a step of liquefying this waste at a temperature of at least 200°C, in particular by pyrolysis or hydrothermal liquefaction, and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase; a3) a step of recovering said hydrocarbon product and separating the liquid phase from said product, said liquid phase forming a plastic liquefaction oil; a4) an optional step of mixing the plastic liquefaction oil with a diluent or a solvent.

[0039] Step a3) may in particular make it possible to recover a liquefaction effluent and separate said liquefaction effluent into a fraction of C1 to C4 hydrocarbons, a fraction having a boiling range greater than 350°C and a fraction being said plastic liquefaction oil.

[0040] Preferably, the plastic liquefaction oil from step a3 or a4 may be sent directly (i.e. without an intermediate treatment step) to the first hydrotreatment step, or may be subjected only to a solids separation step (by filtration, decantation, hydrocyclone, etc.) before being sent to the first hydrotreatment step.

[0041] 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.

[0042] Definitions

[0043] For the purposes of description, the following definitions are given:

[0044] 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.

[0045] 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 measurement.). 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.

[0046] The expressions % by weight and % by mass (denoted indifferently %m or %m / m) have an equivalent meaning and refer to the proportion of the mass of a product relative to 100g of a composition comprising it.

[0047] Unless otherwise stated, measurements given in parts per million (ppm) are expressed by weight.

[0048] The terms "alkane" or "alkanes" as used herein describe branched or unbranched acyclic hydrocarbons having the general formula C n H2n+2, and therefore consisting entirely of hydrogen atoms and saturated carbon atoms; see, for example, IUPAC. Compendium of Chemical Terminology, 2nd edition (1997). The term "alkanes" therefore refers to unbranched alkanes ("normal paraffins" or "n-paraffins" or "n-alkanes" or "paraffins") and branched alkanes ("iso-paraffins" or "iso-alkanes"), but excludes naphthenes (cycloalkanes). They are sometimes designated by the symbol "HC-".

[0049] The terms "olefin" or "alkene" as used herein refer to an unsaturated hydrocarbon compound containing at least one carbon-carbon double bond. They are sometimes denoted by the symbol "HC=".

[0050] The term "alkyne" as used herein refers to an unsaturated hydrocarbon compound containing at least one carbon-carbon triple bond.

[0051] The term "hydrocarbon" refers to alkanes (saturated hydrocarbons), cycloalkanes, aromatics and unsaturated hydrocarbons.

[0052] The Hourly Volume Velocity noted WH is defined as the hourly volume of charge flow per unit of catalytic volume and is expressed here in h' 1 .

[0053] By "heteroatom" we mean any element of an organic compound other than carbon and hydrogen.

[0054] Surface area and pore volume are measured by N2 adsorption using usual surface area measurements. In particular, surface area measurements such as "BET" measurements can be used (i.e., ASTM D3663 for surface area and D4365 for pore volume). Other techniques well known in the art may also be considered, such as mercury adsorption techniques (ASTM D4284). All measurements and data plots used herein were performed with a Micromeritics® Tristar 3000® analyzer. Surface area: Total surface area was determined by N2 sorption analysis in accordance with ASTM D 4365 - 95 (reapproved in 2008). Pore diameter and volume were determined in accordance with D4641 -94 (reapproved in 2006).

[0055] The concentration of metals in the hydrocarbon matrix can be determined by any method known in the art. In particular, relevant characterization methods include X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Analytical scientists know how to identify the most suitable method for measuring each metal and generally each hetero-element 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 standard ISO 20846:2011. The halogen content, including chlorine, bromine, fluorine, can be measured according to the standard: ASTM D7359-18.

[0056] The diene value (DV) or maleic anhydride value (MAV) is the amount of maleic anhydride (expressed as iodine equivalents) that reacts with 100 parts of oil under specific conditions. It is a measure of the conjugated double bonds in the oil. One mole of maleic anhydride corresponds to one conjugated double bond. A known method for quantifying diene is UOP 326-17: Diene Value by Maleic Anhydride Addition Reaction. The term "diene value" (DV) refers to the analytical titration method expressed as g of iodine per 100 g of sample. The term maleic anhydride value (MAV) refers to the analytical titration method expressed as mg of maleic acid per g of sample. There is a correlation between MAV = DV *3.863 since 2 moles of iodine correspond to 1 mole of maleic anhydride.

[0057] The term "Brmine Number" refers to the amount of bromine in grams reacted per 100 g of sample. This number indicates the amount of olefins in a sample. It is determined as grams of Br2 per 100 grams of solution (gBr2 / 100g) and can be measured according to ASTM D1159-07, reapproved in 2017.

[0058] The term "Bromine Index" is the number of milligrams of bromine that react with 100 g of sample. It is determined as milligrams of Br2 per 100 g of solution (mg Br2 / 100 g) and can be measured according to ASTM D2710 or ASTM D5776.

[0059] 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.

[0060] The expression "polar solvent" within the meaning of this patent application covers all chemical species, alone or in mixture, comprising at least one carbon-hydrogen, carbon-halogen, carbon-chalcogen or carbon-nitrogen covalent bond and having a non-zero dipole moment. It is understood that the term "polar solvent" within the meaning of this definition specifically excludes water.

[0061] The term "solvent" includes the aforementioned "polar solvents" and non-polar solvents, which include, for example, any type of linear, branched, cyclic and / or aromatic saturated or unsaturated hydrocarbon such as pentane, cyclohexane, olefins, toluene or xylene or certain other solvents with zero or almost zero dipole moment such as tetrachloromethane or carbon disulfide.

[0062] The term "naphtha" refers to the general definition used in the oil and gas industry. Specifically, it is a hydrocarbon derived from the distillation of crude oil and has a boiling point between 15 and 250°C, according to ASTM D2887. Naphtha contains virtually no olefins because the hydrocarbons are derived from crude oil. It is generally considered that a naphtha has a carbon number between C5 and C11, although the carbon number can reach C15 in some cases. It is also generally accepted that the density of naphtha is between 0.65 and 0.77 g / mL.

[0063] “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.

[0064] The pyrolysis process should be understood as a thermal cracking process, typically carried out at a temperature of 300 to 1000°C or 400 to 700°C, carried out in the presence or absence of a catalyst and / or a gas (fast pyrolysis, flash pyrolysis, catalytic pyrolysis, hydropyrolysis, steam pyrolysis, etc.).

[0065] 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.

[0066] The expression "plastic liquefaction oil" or "oil resulting from the liquefaction of plastic" or "plastic waste liquefaction oil" or "plastic oil" refers to the liquid hydrocarbon products obtained following pyrolysis or hydrothermal liquefaction of plastics, namely 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 filler, 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.

[0067] Plastic can be of any type, including any type of new or used plastic, included in household (post-consumer) or industrial waste. Plastics are understood to mean materials made of polymers and optionally auxiliary components such as plasticizers, fillers, colorants, catalysts, flame retardants, stabilizers, etc. For example, these polymers can be polyethylene, halogenated polyethylene (Cl, F), polypropylene, polystyrene, polybutadiene, polyisoprene, poly(ethylene terephthalate) (PET), acrylonitrile-butadiene-styrene (ABS), polybutylene, poly(butylene terephthalate) (PBT), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, polyamide, polycarbonate, polyether, epoxy polymer, polyacetal, polyimide, polyesteramide, silicone, etc.Generally speaking, any polymer or mixture of polymers capable of producing hydrocarbons by liquefaction can be used.

[0068] 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.

[0069] 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.

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

[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] The different steps described below can be combined depending on the desired purification objective.

[0075] Description of the composition comprising a plastic liquefaction oil

[0076] The composition provided in step (a) comprises a plastic liquefaction oil, said composition containing at least 20 ppm by mass of heteroatoms, in particular from 20 ppm to 30% by mass, a diene number of at least 0.5 g l2 / 100g, in particular from 0.5 to 50 g l2 / 100g, measured according to UOP326 and a bromine number of at least 5 g Br2 / 100g, in particular from 5 to 150 g Br2 / 100g, measured according to ASTM D1159.

[0077] In one embodiment, the composition may comprise only a plastic liquefaction oil, including only a plastic pyrolysis oil or only a plastic hydrothermal liquefaction oil.

[0078] Alternatively, the composition may comprise at least 1 wt% of plastic liquefaction oil. The remainder may then be composed of at most 99 wt% of a diluent or solvent such as a hydrocarbon, and / or one or more of the components listed below, preferably a component derived from biomass, biomass waste or elastomeric waste.

[0079] In one embodiment, the composition may comprise at least 5 wt%, preferably 10 wt%, more preferably at least 25 wt%, even more preferably at least 50 wt%, more preferably 75 wt%, even more preferably at least 90 wt% of plastic liquefaction oil. The composition may comprise at most 80 wt% or 90 wt% or 95 wt% or 100 wt% 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 previously set limits.

[0080] The composition may further comprise a component derived from biomass, biomass waste or elastomeric waste, such as tall oil, used edible oil, animal fat, vegetable oil such as rapeseed, canola, castor, palm, soybean oil, oil extracted from algae, oil extracted from fermentation of oleaginous microorganisms such as oleaginous yeasts, biomass liquefaction oil, in particular biomass liquefaction oil such as Panicum virgatum or lignocellulosic biomass liquefaction oil, for example wood, paper and / or cardboard liquefaction oil, oil obtained by liquefaction of crushed used furniture, elastomer liquefaction oil for example optionally vulcanized latex or tires, and mixtures thereof.

[0081] The composition may further comprise a diluent miscible with the plastic liquefaction oil. This diluent preferably has a diene index of at most 0.5 g I2 / 100 g, in particular from 0 to 0.5 g I2 / 100 g, measured according to UOP 326, a bromine index of at most 5 g Br2 / 100 g, in particular from 0 to 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, in particular from 0 to 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, in particular from 0 to 5 g Br2 / 100 g, and / or a diene number of at most 0.5 gI2 / 100g, in particular from 0 to 0.5 gI2 / 100 g, and / or the effluent from said first and / or second hydrotreatment of the method according to the invention, or any combination thereof.

[0082] The diluent may be added at a concentration of at most 80% by weight, in particular 5 to 80% m, preferably at most 50% by weight. Optionally, the diluent may be separated at the outlet of the first and / or second hydrotreatment by flash distillation or by distillation and, preferably, recycled to the inlet of the first and / or second hydrotreatment.

[0083] The composition provided in step (a) may comprise one or more of the following features, in combination or not with one or more of the preceding features.

[0084] The composition provided in step (a) may have a bromine index of at most 150 g Br2 / 100g, preferably at most 100 g Br2 / 100g, even more preferably at most 80 g Br2 / 100g, most preferably at most 50 g Br2 / 100g, as measured according to ASTM D1159. The composition may further have a heteroatom content of at least 20 ppm and at most 30% wt. In particular, the composition may comprise silicon, chlorine, oxygen and nitrogen, and / or other heteroatoms from the plastic liquefaction oil.

[0085] In the composition provided in step (a), at least 10% by weight, in particular from 10 to 90 or 100%m, preferably at least 15% by weight, preferably at least 25% by weight, more preferably at least 50% by weight of said composition may have a boiling point of at least 150°C relative to the total weight of said composition, in particular a boiling point of 150°C to 700°C, advantageously from 150 to 600°C, more preferably from 150 to 560°C, even more preferably from 150 to 450 or 350°C.

[0086] Step (a) of providing the composition may comprise:

[0087] (a1) a step of supplying a waste stream of plastics or containing plastics,

[0088] (a2) a step of liquefying the waste containing plastics at a temperature of at least 200°C, in particular from 200 to 1000°C, and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase, (a3) ​​a step of recovering said hydrocarbon product (i.e. the liquefaction effluent) and separating the liquid phase from said product, said liquid phase forming a plastic liquefaction oil,

[0089] (a4) an optional step of mixing the plastic liquefaction oil with a diluent or solvent.

[0090] The liquefaction step (a2) 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.

[0091] Alternatively or in combination, the liquefaction step (a2) 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.

[0092] The waste supplied in step (a1) may be plastic waste possibly mixed with biomass and / or elastomers, as previously described.

[0093] The recovery and separation step (a3) ​​makes it possible to eliminate the gaseous phase, essentially the C1-C4 hydrocarbons, and the solid phase (typically char), and optionally an aqueous fraction, to recover only the liquid organic phase forming a liquefaction oil. In particular, a fraction having a boiling range greater than 350°C, in particular from 350 to 700°C, and a fraction being said plastic liquefaction oil can be separated.

[0094] Plastic liquefaction oils contain, among other things, paraffins, i-paraffins (isoparaffins), dienes, alkynes, olefins, naphthenes, and aromatics. Plastic liquefaction oils also contain impurities containing heteroatoms, such as chlorinated, oxygenated, sulfurous, nitrogenous, and / or silylated organic compounds, metals, salts, and phosphorus compounds.

[0095] The composition of plastic liquefaction oil depends on the nature of the liquefied plastic, and optionally on any other waste (biomass and / or elastomers) liquefied with the plastic, and is essentially (in particular at more than 80% m / m, most often at more than 90% m / m) made up of hydrocarbons having from 1 to 150 carbon atoms and impurities.

[0096] A plastic liquefaction oil typically comprises 5 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.

[0097] A plastic liquefaction oil may include one or more of the features described below or previously described in this application.

[0098] In particular, a plastic liquefaction oil may comprise a Bromine number of 10 to 130 g Br / 100 g, as measured according to ASTM D1159, and / or a maleic anhydride number (UOP 326) of 1 to 55 mg maleic anhydride / 1 g and / or a diene number of at most 50 gl2 / 100 g, preferably at most 25 gh / 100 g, more preferably at most 10 gh / 100 g, measured according to UOP 326. In a preferred embodiment, said plastic liquefaction oil has an initial boiling point of at least 15°C, and a final boiling point of at most 700°C, preferably at most 600°C, even more preferably at most 560°C, more preferably of at most 450°C, even more preferably of at most 350°C, preferably of at most 250°C (measured according to standard NF EN 15199-1 / 2).

[0099] A plastic liquefaction oil typically comprises at least 20 ppm heteroatoms, possibly at least 30 ppm heteroatoms, and possibly up to 30 wt% heteroatoms.

[0100] A plastic liquefaction oil may in particular comprise one or more of the following heteroatom contents: from 0 to 8% w / w oxygen (e.g. measured according to ASTM D5622), from 1 to 20000 ppm or from 1 to 13000 ppm nitrogen (e.g. measured according to ASTM D4629), from 2 to 20000 ppm or 2 to 10000 ppm sulfur (e.g. measured according to ISO 20846), from 1 to 10000 ppm metals, in particular more than 2 ppm (e.g. measured by ICP), from 50 to 6000 ppm chlorine, preferably at most 5000 ppm (e.g. measured according to ASTM D7359-18), from 0 to 200 ppm bromine (e.g. measured according to ASTM D7359-18), from 1 at 40 ppm fluorine (e.g. measured according to ASTM D7359-18), 1 to 5000 ppm silicon, preferably at most 1000 ppm (e.g. measured by XRF), at least 1 ppm P, preferably at most 5000 ppm P.

[0101] Detailed description of the optional composition processing step provided in step

[0102] Between step (a) and (b), the invention may also comprise an optional pretreatment step, in which the 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, (v) a hydrocyclone or (vi) the combination of at least two of steps (i) to (iv). This additional step may make it possible to remove some of the impurities contained in the composition such as oxygen, nitrogen, chlorine, sulfur or other heteroatoms. In particular, the reduction in the amount of oxygen may make it possible to avoid the formation of solids and / or gels during step (d), in particular when the latter comprises a washing step (d1).

[0103] In the additional washing step (ii), the polar solvent or water / composition volume ratio may be from 1 / 99 to 90 / 10, from 10 / 90 to 90 / 10, from 20 / 80 to 80 / 20, from 30 / 70 to 70 / 30, from 35 / 65 to 65 / 35, from 35 / 65 to 60 / 40, or from 40 / 60 to 60 / 40.

[0104] When water is used for washing (ii), it may have an acidic, basic or neutral pH. An acidic pH may be obtained by the addition of one or more organic or inorganic acids. Examples of suitable organic acids include citric acid (CeHsO?), formic acid (CH2O2), acetic acid (CH3COOH). Examples of inorganic acids are sulfamic acid (H3NSO3), hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4). A basic pH may be obtained by the addition of alkali and alkaline earth metal oxides, alkali and alkaline earth metal hydroxides (e.g. NaOH, KOH, Ca(OH)2), alkali and alkaline earth metal bicarbonates and amines (e.g. triethylamine, ethylenediamine, ammonia).

[0105] The polar solvent may have a density greater or less than the density of the composition comprising a plastic liquefaction oil.

[0106] In particular, the density of the polar solvent may be 3 to 50% higher or lower than that of the composition.

[0107] The polar solvent is a solvent immiscible with the composition comprising a plastic liquefaction oil to be purified.

[0108] 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.

[0109] This recovery rate can be determined in particular by following the following procedure:

[0110] 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,

[0111] Introduce 2 mL of solvent into the flask, using a precision pipette + / -0.1 mL,

[0112] Insert a magnetic bar, close the balloon with a polypropylene stopper,

[0113] Stir the mixture on a mechanical stirrer plate at a speed of 500 rpm for 5 min,

[0114] At the end of the 5 minutes, stop stirring, remove the magnetic bar using a magnetic rod,

[0115] 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.

[0116] 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 (DM F), 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Description of the first hydrotreatment stage

[0121] This first step consists mainly of a hydrogenation phase aimed at saturating the conjugated dienes and alkynes into olefins. Depending on the composition treated, the first hydrotreatment step is carried out either in the liquid phase or in a fluidized bed. This first hydrotreatment step hydrogenates the dienes, and in particular the conjugated dienes, and the acetylenic bonds. The first hydrotreatment step thus results in a reduction in the diene index. The reduction in the diene index observed between the inlet and the outlet of the first hydrotreatment step is typically at least 10%, preferably at least 25%, measured according to the UOP 326 standard. This reduction can be at least 70%, 80%, or even at least 90% and up to 99%.

[0122] This step thus makes it possible to obtain a hydrotreated composition forming the first effluent, notably having a reduced diene content (and therefore a reduced diene index) and / or a reduced alkyne content.

[0123] During this first step, the composition provided in step (a), optionally pretreated, is hydrotreated, preferably selectively hydrogenated, at a temperature of 80 to 250°C, preferably 130 to 250°C, more preferably 200 to 250°C, in the presence of dihydrogen and in the presence of a first hydrotreatment catalyst.

[0124] Typically, the inlet temperature may be from 25 to 250°C, preferably from 130 to 250°C. During this first step, the composition may pass through one or more catalytic beds, preferably with an overall increase in temperature of at most 150°C, in particular from 5 to 150°C, preferably of at most 100°C, and / or an increase in temperature of at most 100°C, in particular from 5 to 100°C, preferably of at most 50°C for each catalytic bed. Advantageously, an intermediate quench may be provided between the catalytic beds, preferably carried out with H2 or with the purified composition recovered in step (f).

[0125] This first step can be carried out in a fixed bed reactor, preferably in the presence of at least one catalyst, typically a hydrogenation catalyst.

[0126] It may be a catalyst comprising at least one metal from groups 8-10, most often one, two or three of these metals, preferably chosen from the group Pt, Pd, Ni and / or their mixture on a support such as alumina, titanium, silica, zirconia, magnesia, carbon and / or their mixtures. For example, a Ni-based catalyst passivated after its reduction will be used, preferably using a di-alkyl sulfide such as Dimethylsulfide (DMS) or DiMethylDiSulfide (DMDS) or DiEthylSulfide (DES), or thiophene compounds.

[0127] It may also be a catalyst comprising at least one metal from group 6, most often one or two of these metals, such as for example Mo, W, in combination or not with a promoter chosen from at least one metal from groups 8-10, most often one or two of these metals, such as for example Ni and / or Co, and / or a mixture thereof, these metals being used in sulphide form and preferably supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof.

[0128] 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) may be used.

[0129] The first step is typically carried out at an absolute pressure of 5 to 90 bar, preferably 10-50, more preferably 25-50 bar in the presence of H2. Alternatively or in combination, the molar ratio of H2 to the total molar sum of alkynes and dienes present in said composition is at least 1.5, preferably at least 2, preferably at least 3, to at most 15.

[0130] This step (b) can be carried out in a single reactor with several catalytic beds placed in series with possible hydrogen make-up between the beds or in several reactors in series and / or parallel depending on the desired objective. Guard reactors can be used upstream or downstream of the first hydrogenation reactor. These guard reactors can 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.

[0131] This hydrotreatment step can also have a demetallation, cracking, dearomatization function depending on the characteristics of the catalyst and the hydrotreatment conditions.

[0132] The feedstock for the hydrotreatment may advantageously be heated by a heat exchanger which is supplied with the hydrotreatment effluent. Preferably, the feedstock for the hydrotreatment may be diluted with a portion of the hydrotreatment effluent, still having a higher temperature than the desired temperature at the hydrotreatment inlet. 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.

[0133] Preferably, the part of the hydrotreatment effluent which is not recycled but still at a high temperature can exchange its sensible heat with the effluent before the hydrotreatment of the latter and thus ensure its preheating.

[0134] At the outlet of the first hydrotreatment stage, the first effluent may have a diene index of at most 1.5 g I2 / 100 g, in particular from 0.01 to 1.5 g / 100 g, preferably at most 1.0 g I2 / 100 g, more preferably at most 0.5 g I2 / 100 g.

[0135] At the outlet of the first hydrotreatment stage, the first effluent can optionally be subjected to flash distillation in order to eliminate all or part of the gas phase it contains. This can in particular make it possible to recover the dihydrogen present in the gas phase which has not reacted.

[0136] Description of basic processing step (c)

[0137] Step (c) is a step of treating the first effluent leaving step (b) (optionally after having been subjected to flash distillation) in the presence of a basic compound, preferably a nucleophilic basic compound, at a temperature of at most 350°C to obtain a second effluent.

[0138] This treatment makes it possible in particular to modify compounds containing heteroatoms and to promote their subsequent elimination. The reduced diene and / or alkyne content of the first effluent leaving the first hydrogenation stage makes it possible to carry out stage (c) at a high temperature without the risk of clogging the installation and thus improve the efficiency of the basic treatment.

[0139] Step (c) may be carried out at a temperature of at most 350°C. In one embodiment, step (c) may be carried out at a temperature of 100 to 350°C, more preferably 180 to 300°C, more preferably still 200 to 300°C or 180 to 250°C or 180 to 280°C, or in any range defined by any two of these limits.

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

[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 30 minutes, at a temperature of at most 250°C, more preferably at most 225°C. In this particularly preferred embodiment, step (c) can be carried out at a temperature of at least 100°C, preferably at least 150°C, more preferably at least 180°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] Advantageously, whatever the embodiment, the quantity of basic compound used is from 0.1 to 50% m, preferably from 0.1 to 40% m, more preferably from 0.1 to 30% m, preferably from 0.1 to 20% m, even more preferably from 0.1 to 15% m relative to the total mass of the treated effluent (first effluent produced by step (b)).

[0143] Preferably, optionally in combination with the particularly preferred embodiment, the amount of basic compound used is at least 0.5%m, more preferably at least 1%m, even more preferably at least 3%m, even more preferably at least 5%m or even at least 10%m, and at most 50%m, 40%m, 30%m, 20%m or 15%m, relative to the total mass of the treated effluent (first effluent produced by step (b)).

[0144] In one embodiment, optionally in combination with the particularly preferred embodiment, during step (c), the first effluent 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, more preferably with 1 to 15% by mass of a basic compound, more preferably from 1 to 10% by mass, in particular from 1 to 5% by mass relative to the total mass of the treated effluent (first effluent produced by step (b)), or in any interval defined by two of the preceding limits.

[0145] The basic compound may be added to the first effluent either before step (c) or during step (c). This addition of the basic compound to the first effluent may optionally be followed by a mixing step.

[0146] The basic compound may be added to the first effluent in solid form or solubilized in an aqueous medium, preferably water, or in a solvent, miscible or immiscible with the second effluent.

[0147] 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.

[0148] A usable immiscible solvent may be an immiscible polar solvent, for example those cited for the optional pre-treatment step.

[0149] 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.

[0150] 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, EtONa, MeONa, NH4OH, TEAOH, TBuOH, TMAOH, and mixtures thereof. A preferred basic compound may be selected from NaOH, KOH, and mixtures thereof, preferably in solution in water. The solvent used to solubilize the basic compound may be water, an alcohol, for example methanol or ethanol, or any other organic solvent that can solubilize the selected basic compound, preferably water.

[0151] When the basic compound is solubilized in a solvent, the person skilled in the art will then choose a quantity of solvent sufficient to dissolve / solubilize it, preferably the smallest possible quantity of solvent.

[0152] Advantageously, optionally in combination with the particularly preferred embodiment, 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 25% to 50% by mass, more preferably from 40 to 50% by mass, even more preferably the water or solvent is saturated with basic compound.

[0153] Whatever the embodiment, the volume ratio of the solvent containing the basic compound / first effluent, i.e. the volume ratio of the mixture (basic compound + solvent) / first effluent, 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. A solution, in particular an aqueous solution, saturated with basic compound may be used.

[0154] In a particularly preferred embodiment, optionally in combination with the aforementioned particularly preferred embodiment, the first effluent may advantageously be brought into contact with:

[0155] 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, 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 with water 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), even more preferably with water saturated with basic compound.

[0156] 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.

[0157] The basic treatment of step (c) can be carried out in any device allowing contact between the basic compound and the effluent. This can be a reactor, preferably equipped with a mixing device.

[0158] Step (c) may further be carried out under turbulent regime conditions or under cavitation conditions, in particular hydrodynamic cavitation, in order to improve the mixing while reducing the contact time. The turbulent regime is obtained when the flow has a Reynolds number of at least 2000, preferably at least 3000, more preferably at least 4000, or even at least 10000. The turbulent regime may advantageously be achieved by using at least one static mixer. That is to say, the composition and the aqueous medium are introduced into at least one tube equipped with at least one internal element capable of generating the turbulent regime having a Reynolds number of at least 2000.

[0159] Hydrodynamic cavitation occurs in all hydraulic systems in which considerable pressure differences occur, such as turbines, pumps, and high-pressure nozzles. The effective conditions for generating cavitation characteristics depend on the properties of the fluid flow, the design of the cavitation device, the flow velocity, for example achieved by a pump, and the temperature of the fluid flow and can be readily determined by those skilled in the art. A suitable hydrodynamic cavitation device may have a throttling (constriction) section formed by a plate having one or more orifices, a venturi tube, a rotor-stator system, or a liquid whistle. Instead of a constriction section, a vortex diode having a tangential inlet and an axial outlet may also be used to generate the cavitation bubbles.Examples of usable technologies include vortex-type hydrodynamic cavitation generators, such as the VoDca® generator from Water Knight in the Netherlands, a high-pressure homogenizer, e.g., the Sonolator® high-pressure homogenizers, and rotor-stator rotating equipment, e.g., the Rotocav® from Cavimax in the UK.

[0160] At the outlet of step (c), the hydrotreated composition contained in the second effluent, in particular forming the second effluent, is thus modified because the impurities (the compounds containing heteroatoms, and in particular silicon, chlorine, oxygen and nitrogen) have been modified by the basic treatment, facilitating their subsequent elimination by washing and / or separation.

[0161] In step (d), the second effluent leaving step (c) may be subjected to at least one step chosen from (d1) washing with water or a solvent immiscible with the second effluent, and in particular with the modified composition, (d2) separation by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation, (v) distillation or (iv) a combination of two or more of these steps. This step (d) makes it possible to recover a third purified effluent having a reduced content of heteroatoms, in particular chlorine and silicon but also nitrogen and oxygen, and a phase (solid or liquid) containing the basic compound, and typically heteroatoms initially contained in the second effluent. This step thus makes it possible to eliminate the impurities present in the second effluent.In other words, during this step, the modified hydrotreated composition from step (c) is purified and a purified composition is recovered separately having a reduced content of heteroatoms (in particular silicon, and possibly also oxygen, chlorine, nitrogen) forming the third effluent, and a phase (solid or liquid) containing the basic compound, and typically heteroatoms initially contained in the second effluent. In particular, at the outlet of step (d), the content of nitrogen, oxygen, chlorine and silicon can be reduced by at least 50%, or even at least 60%, most often at least 70% or 80%. It is in particular possible to reduce up to 98% of the silicon, up to 97% of the chlorine, up to 95% of the oxygen and up to 70% of the nitrogen, or even up to 99% of each of these elements. The overall heteroatom content can be reduced by at least 30% or even at least 40% and up to 99%.

[0162] The choice of steps (d1) and (d2) depends in particular on the nature of the basic compound and the desired purification objective.

[0163] A solids separation step (d2) can thus be particularly advantageous before another liquid-solid separation step (d2) because it can facilitate phase separation by eliminating all or part of the solids present in the effluent from step (c).

[0164] For example, we can distinguish cases (A), (B) and (C) below, although other combinations are nevertheless possible depending on the objective sought:

[0165] (A) during step (c) the basic compound is added to the first effluent in the form of a solid basic compound, step (d) can then comprise:

[0166] (A1) the washing step (d1) which makes it possible to recover a liquid phase forming the third effluent and a phase containing the basic compound, the impurities, and the water or the solvent used for washing, or

[0167] (A2) the separation step (d2), 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 forming the third effluent, or

[0168] (A3) the separation step (d2) can be followed by a washing step (d 1 ) of the liquid phase recovered at the outlet of step (d2),

[0169] (B) during step (c) the basic compound is added to the first effluent solubilized in a solvent miscible with the first effluent, step (d) can then comprise the washing step (d1) which makes it possible to recover a phase forming the third effluent and a phase containing the miscible solvent, the solubilized basic compound, the impurities, and the water or the immiscible solvent used for washing;

[0170] (C) during step (c) the basic compound is added to the first effluent solubilized in an aqueous medium or in a solvent immiscible with the first effluent, step (d) can then comprise:

[0171] (C1) the washing step (d1) which makes it possible to recover a phase forming the third effluent and a phase containing the basic compound, the impurities, the water or the solvent used for washing and the aqueous medium or the immiscible solvent used to add the basic compound, or

[0172] (C2) the separation step (d2), typically a liquid-liquid separation, which makes it possible to separate the phase forming the third effluent and a phase containing the water or the immiscible solvent, the basic compound and the impurities, or (C3) the separation step (d2) described above followed by a washing step (d1) of the phase forming the third effluent, recovered at the outlet of step (d2).

[0173] In cases (A2), (A3), (C2) and (C3), it is advantageous to recover the phase containing the basic compound recovered at the outlet of the separation step (d2) and return it in whole or in part to the basic treatment step (c). This makes it possible to reduce the quantities of basic compound to be used and thus reduce the associated costs.

[0174] Depending on its olefin and / or heteroatom content, the third effluent leaving step (d) may form a purified composition which can then be sent to other subsequent treatments or used as is. This is particularly the case when the olefin and / or heteroatom contents of the third effluent are lower than target values, corresponding for example to maximum values ​​required for subsequent treatments or uses.

[0175] Thus, at the outlet of step (d), the olefin concentration, measured by the bromine index in the third effluent, may be at most 5.0 gBr2 / 100g, for example from 0.01 to 5.0 gBr2 / 100g, preferably at most 2.0 gBr2 / 100g, preferably at most 1.5 gBr2 / 100g, more preferably at most 0.5 gBr2 / 100g, measured according to standard ASTM D1159.

[0176] In combination or alternatively, at the outlet of step (d), the heteroatom content in the third effluent may be less than 5 ppm or even less than 3 ppm or zero.

[0177] Detailed description of washing step (d1)

[0178] The washing step (d1) is carried out with water at neutral, basic or acidic pH or with a solvent immiscible with the effluent. The washing step (d1) makes it possible to recover a phase containing the second purified effluent and forming the third effluent, and a phase containing the water or the immiscible solvent used for washing, the basic compound and the impurities. In other words, at the outlet of the washing step, these phases are recovered separately, for example following a liquid / liquid separation (centrifugation and / or decantation and / or other) carried out at the end of the washing step.

[0179] This step (d1) makes it possible to eliminate the impurities containing heteroatoms present in the second effluent leaving step (c) by solubilizing them in a solvent (water or an organic solvent).

[0180] This washing step (d1) can also make it possible to separate the basic compound from the second purified effluent. The washing step (d1) is thus particularly advantageous when the basic compound used during step (c) is added to the first effluent in solid form or dissolved in a solvent miscible with the effluent to be treated, but can also be implemented when the basic compound is solid or in solution in a solvent (water or organic solvent) immiscible with the effluent to be treated.

[0181] When the basic compound used in step (c) is solid or solubilized in water or a solvent immiscible with the effluent to be treated, this washing step (d1) can be omitted or carried out after the separation step (d2), as explained below.

[0182] Depending on the desired objective, step (d1) may be preceded and / or followed by one or more separation steps (d2). The water used in step (d1) may have an acidic pH (pH<7), basic (pH>7) or neutral (PH=7).

[0183] 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 metal or alkaline earth metal cation.

[0184] An acidic pH may be obtained by the addition of one or more organic or inorganic acids. Examples are given with reference to washing (ii) of the optional pre-treatment step. Preferably, the water may have a pH of 0.1 to 6.9.

[0185] A basic pH may be obtained by adding one or more basic compounds, for example those mentioned above with reference to washing (ii) or those used in step c). Preferably, the water may have a pH of 7.1 to 14.

[0186] The immiscible solvent may be any organic solvent immiscible with the effluent to be treated, in particular in which the impurities containing heteroatoms are soluble. A usable immiscible solvent is, for example, a polar solvent, in particular those described in the optional pre-treatment step.

[0187] In one embodiment, step (d1) 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 (d1) may however advantageously be carried out at a higher temperature, for example at the temperature of the effluent leaving step (c) or the step preceding step (d1).

[0188] Step (d1) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step (c) or the step preceding step (d1) is carried out.

[0189] Step (d1) can be carried out on the effluent directly from step (c), without an intermediate step, or on the effluent leaving step (d2). When it follows step (d2), the washing step (d1) then makes it possible to eliminate any residue of the basic compound and / or impurities containing heteroatoms, still present in the effluent leaving step (d2), which can make it possible to obtain a purified composition having in particular an alkali or alkaline-earth metal content of less than or equal to 2 ppm (by mass), or even zero.

[0190] In step (d1), the solvent or water / effluent volume ratio 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.

[0191] Step (d1) may comprise, or consist of, bringing the effluent from step (c) or (d2) into contact with water or an immiscible solvent by any means known in the prior art.

[0192] For example, the effluent from step (c) or (d2) and the solvent or water may be introduced into tanks, reactors or mixers commonly used in the profession and the two components may be mixed. The contacting may comprise vigorous agitation of the two components by a mixing device. For example, the two components may be mixed together by stirring or shaking. Alternatively, the contacting may be carried out in an enclosure in which the two components circulate countercurrently, for example in contact columns with suitable packing in order to increase the contact between the phase of the composition being treated and the water or an immiscible solvent. Alternatively, the contacting may be carried out in a static mixer in co-current mode or in a cavitation section. This contacting may occur more than once, in particular under the conditions presented above.

[0193] The washing step (d1) can be implemented continuously or in batch.

[0194] Detailed description of separation step (d2)

[0195] The separation step (d2) also makes it possible to separate the second purified effluent to obtain a phase forming the third effluent having a reduced heteroatom content, and a phase containing the basic compound and the impurities. This may be a liquid / liquid separation or a solid / liquid separation. It may advantageously be carried out by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation, (v) distillation, in particular atmospheric or pressurized distillation, or (iv) by the combination of at least two of these steps.

[0196] Step (d2) can be carried out directly on the effluent from step (c). In this case, it makes it possible to separate the effluent from the basic compound, in particular when the latter has been added in solid form or in a solvent immiscible with the effluent (water or immiscible organic solvent). This step (d2) then separates a phase forming the third effluent and a phase containing the basic compound and the impurities, and, where appropriate, the water or the solvent immiscible with the effluent. This phase containing the basic compound can then be returned to step (c) to reuse the basic compound. This makes it possible to reduce the total quantity of basic compound consumed in step (c).

[0197] Prior to step (d2), the effluent containing the modified composition leaving step (c) may be treated in at least one mechanical or electrostatic coalescer in order to break any emulsion and concentrate the basic compound in the solvent or water.

[0198] In one embodiment, step (d2) 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 (d2) may however advantageously be carried out at a higher temperature, for example at the temperature of the effluent leaving step (c) or the step preceding step (d2).

[0199] Step (d2) is typically carried out at atmospheric pressure or at a pressure close to the pressure at which step (c) or the step preceding step (d2) is carried out.

[0200] Optional trapping step (e)

[0201] The effluent from step (d) 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. Typically, the third effluent may be brought into contact with silica gel, clays, alkali or alkaline earth metal oxide, iron oxide, ion exchange resins, activated carbon, active aluminum oxide, molecular sieves, alkali oxide and / or porous supports containing modified or unmodified lamellar double hydroxide and silica gel, or any mixture thereof to trap silicon and / or metals and / or phosphorus and / or halogenates.

[0202] The adsorbent may be operated in regenerative or non-regenerative mode, at a temperature below 400°C, in particular from 20 to 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.,

[0203] According to a preferred embodiment, the adsorbent is regenerable, has a specific surface area of ​​at least 200 m 2 / g and is operated, for example in a fixed bed reactor, at a temperature below 100°C and / or a WH of 0.1 to 10 h -1 and / or at a pressure of 1 to 90 bar in the presence of H2 or in the absence of H2.

[0204] Optional second hydrotreatment stage

[0205] This second optional hydrotreatment step is typically implemented when the olefin and / or heteroatom contents of the third effluent are higher than target values, corresponding for example to maximum values ​​required for subsequent treatments or uses. During this step, a more purified composition forming the fourth effluent is thus obtained and having a reduced olefin and / or heteroatom content compared to the contents of the third effluent.

[0206] This second hydrotreatment step (f) consists of a step at a temperature of at least 200°C, in the presence of dihydrogen and at least one hydrotreatment catalyst. Typically, a known catalyst will be used to hydrogenate olefins and convert the sulfur and nitrogen components into H2S and NH3 respectively. Depending on the composition of the third effluent entering this second hydrotreatment step, it can be carried out in the gas phase where the reactor operates in "trickle bed" mode.

[0207] This step can also have a metal trap function, a cracking function, a dearomatization function depending on the characteristics of the catalyst and the operating conditions used. This step can be carried out in a single reactor with different layers of catalysts or in several reactors in series depending on the desired function.

[0208] Optionally, the third effluent may be diluted before being sent to this second hydrotreatment stage. The nature and / or proportions of diluent that can be envisaged are, for example, as described above with reference to the composition. The diluent may optionally be separated at the outlet of the second hydrotreatment stage.

[0209] During this second stage, the third effluent is hydrotreated, at a temperature of 200 to 500°C, preferably 200 to 450°C, more preferably 250 to 340°C.

[0210] Typically, the inlet temperature may be at least 200°C, preferably at least 230°C, more preferably at least 250°C and at most 500°C.

[0211] This step is typically carried out at an absolute pressure of 10 to 160 bar, preferably 10 to 100 bar and / or an H2 / hydrocarbon ratio of 200 NL / L to 900 NL / L.

[0212] Preferred operating conditions are advantageously as follows: the preferred inlet temperature is at least 200°C and at most 500°C; a preferred WH is 1 to 10 h -1 , preferably 2 to 4 tr 1 ; the preferred pressure is from 10 to 90 bar absolute in the presence of H2; the hL / hydrocarbons ratio is from 200 NL / L to 900 NL / L, preferably in the presence of at least 0.005% by weight, in particular from 0.005 to 1% by weight, preferably 0.05% by weight, more preferably 0.5% by weight of sulfur, preferably H2S or organic sulfur compounds, in the stream.

[0213] During this second step, the third effluent may pass through one or more catalytic beds, preferably with an overall increase in temperature of at most 100°C, in particular from 5 to 100°C, and / or an increase in temperature of at most 50°C on each catalytic bed, in particular from 5 to 100°C. Advantageously, an intermediate quench may be provided between the catalytic beds, this quenching preferably being carried out with H2 or with the purified composition recovered in step f).

[0214] This second step can be carried out in a fixed bed reactor, preferably in the presence of at least one catalyst, typically a hydrogenation catalyst.

[0215] It may be a catalyst comprising a hydrogenating function, namely at least one metal from group 6, most often one or two of these metals, such as for example Mo, W, in combination or not with a promoter chosen from at least one metal from groups 8-10, most often one or two of these metals, such as for example Ni and / or Co, and / or a mixture thereof, these metals preferably being used in sulphurized form and supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof.

[0216] The catalyst can also have a trap function and for this purpose have a BET surface area of ​​150 m 2 / g at 400 m 2 / g.

[0217] For example, a NiMo (0.1-60% by weight) and / or C0M0 (0.1-60% by weight) type catalyst can be used. Guard reactors can also be provided to eliminate any chlorine, metals and silicon that may still be present.

[0218] Thus, a silicon trap may be provided at the inlet of the second hydrotreatment stage, which may be in a separate reactor or form the upper bed of a reactor. This trap may operate at a temperature of at least 200°C, in particular from 200 to 500°C, and / or at a WH of 1 to 10h-1, and / or at an absolute pressure of 10 to 160 bar in the presence of H2; possibly with a metal trap operating at a temperature of at least 200°C, in particular from 200 to 500°C, at a WH of between 1 and 10h-1, at an absolute pressure of 10 to 90 bar in the presence of H2. The basic treatment of stage (c) makes it possible in particular to reduce the size of the silicon trap when it is present.

[0219] Depending on the metals present in the liquefaction oil to be hydrotreated, a hydrodemetallization catalyst, for example a commercial one, can be added to the upper bed of the hydrotreatment section in order to protect the lower catalyst beds from deactivation.

[0220] The feed for hydrotreatment can be advantageously heated by a heat exchanger which is fed by the effluent from the hydrotreatment.

[0221] Preferably, the feedstock for the hydrotreatment may be diluted with a portion of the hydrotreatment effluent, still having a higher temperature than the desired temperature at the hydrotreatment inlet. 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.

[0222] Preferably, the part of the hydrotreatment effluent which is not recycled but still at a high temperature can exchange its sensible heat with the effluent before the hydrotreatment of the latter and thus ensure its preheating.

[0223] At the outlet of this second hydrotreatment stage, the olefin concentration, measured by the bromine index in the fourth effluent, may be at most 5.0 gBr2 / 100g, in particular from 0.01 to 5.0 gBr2 / 100g, preferably at most 2.0 gBr2 / 100g, preferably at most 1.5 gBr2 / 100g, more preferably at most 0.5 gBr2 / 100g, measured according to standard ASTM D1159.

[0224] In combination or alternatively, at the outlet of the second hydrotreatment stage, the heteroatom content in the fourth effluent may be less than 5 ppm or even less than 3 ppm or even zero.

[0225] Optional washing step

[0226] The effluent from the second hydrotreatment stage, namely the fourth effluent, may be washed to remove inorganic compounds such as sulfur, chlorine and nitrogen compounds before being subjected to further treatments.

[0227] In particular, the removal of inorganic compounds can be carried out by washing with water at the outlet of the hydrotreatment reactor and / or further downstream by washing with amines. Typically, at the outlet of the second hydrotreatment stage, the effluent, generally recovered by condensation, can be washed with water to remove salts from the liquid phase (such as NH4HS, NH4Cl, etc.), then subjected to flash distillation in order to separate a liquid phase and a lighter gaseous phase (containing for example fuel gas, LPG, etc. as well as H2S, NH3 and HCL). Washing the gaseous phase with amines makes it possible to remove H2S from the other gases. The liquid phase from the flash distillation and the gaseous phase after washing with amines can then be used as a purified composition and be separated into usable streams and / or treated as described below.

[0228] Use of the

[0229] The purified composition leaving step (d), optionally further purified by passing over a solid adsorbent, or the purified composition leaving step (f) optionally washed, 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.

[0230] The purified composition leaving step (d) optionally further purified by passing over a solid adsorbent, or the purified composition leaving step (f) optionally washed can also be used diluted, for example mixed with naphtha, gas oil or crude oil in order to obtain a concentration of purified plastic liquefaction oil ranging from 0.01% by weight to 50% by weight at the most; 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.

[0231] Detailed description of the optional steam cracking step

[0232] The steam cracking step can be carried out on the purified composition leaving step (d), optionally purified by passing over a solid adsorbent, or on the purified composition leaving step (f), optionally washed, with or without dilution with a conventional steam cracking feedstock. Prior to this steam cracking step, a separation step by distillation can be carried out depending on the technology of the steam cracking furnaces.

[0233] This steam cracking step produces olefins such as ethylene and propylene and aromatics. Ethylene and propylene can then be advantageously converted into polyethylene and polypropylene respectively in a polymerization section.

[0234] The steam cracking step consists of thermally cracking in one or more furnaces a mixture of the purified 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 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 side 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.

[0235] The purified composition exiting step (d), optionally further purified by passing over a solid adsorbent, or the purified composition exiting stage (f), optionally washed, may be sent to the steam cracker without dilution or may be mixed 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 into olefins, such as ethylene and propylene, as well as aromatics.

[0236] In a preferred embodiment, the purified 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.

[0237] 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).

[0238] 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.

[0239] 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.

[0240] 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.

[0241] In a preferred embodiment, the steam cracking is carried out in the presence of steam 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. 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 achieved (i) by maintaining 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.

[0242] Since the purified 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 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 at the bottom by gravity and the hydrocarbon vapors at the top. Optionally, the hydrocarbon liquid may be returned to the plastics liquefaction unit or to the optional hydrocracking step.

[0243] Detailed description of the optional hydrocracking step

[0244] Prior to the steam cracking step, the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the hydrotreated effluent from step (f), optionally washed, 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.

[0245] 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 .

[0246] 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 6 chosen from chromium, molybdenum and tungsten, alone or as a mixture, and / or at least one metal from groups 8-10 chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0247] 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.

[0248] Description of figures

[0249] Figure 1 describes a possible embodiment of the invention. In this possible embodiment, the plastic liquefaction oil composition (1) is first optionally pretreated in a pretreatment section (P) to be subjected therein to a pretreatment (PTT) by (i) filtration, (ii) washing with water or a polar solvent, (iii) distillation, (iv) decantation, or (v) the combination of two, three or four of steps (i) to (iv), preferably a pretreatment consisting only of removing solids. The pretreated composition (2) is then sent to a hydrotreatment section (B) for the implementation of a first hydrotreatment step HDT1 corresponding to step (b) of the invention.The first effluent (3) which leaves this first hydrotreatment section, namely the hydrotreated composition, can then be subjected to flash distillation in order to separate at least part of the gases in a flash distillation section (DF), or else be sent directly to a treatment section (C) to implement the basic treatment step TTbase according to step (c) of the invention. The effluent (5) from the TTbase step, namely the modified hydrotreated composition, is then sent to a separation section (D) for the implementation of step (d). This section (D) can thus comprise a washing section and / or a separation section. When this section implements step (d2), the phase (7) containing the basic compound can optionally be returned to the section (C) of the basic treatment TTbase.The effluent (6) leaving the separation section (D), namely the modified composition, can then be sent to an optional purification section (E) by treatment on a TTads adsorbent implementing step (e) of the present invention to be further purified therein. The effluent (8) leaving the separation section (D) or the effluent (9) leaving the purification section (E) is then sent to a second optional hydrotreatment section (F) for the implementation of a second hydrotreatment step HDT2 corresponding to step (f) of the invention.

[0250] The effluent (9), namely a more purified composition (compared to the previous step), leaving the second hydrotreatment section (F), optionally after fractionation and / or dilution, can be used as is or sent to one or more of the following optional sections: an optional hydrotreatment section (S-HDT), an optional treatment section (S-VAPO) in a steam cracker, an optional treatment section (S-HC) in a hydrocracker, an optional treatment section (S-FCC) in a fluidized catalytic cracker, an optional preparation section (S-Pool) of a fuel or a combustible or a lubricant or a base oil. Preferably, the effluent (9) leaving the hydrotreatment section (F) is then steam cracked to obtain olefins which can then be polymerized.Preferably, the effluent (9) leaving the hydrocracking section (S-HC) is then steam cracked to obtain olefins which can then be polymerized.

[0251] Alternatively or in combination, the effluent (8) leaving the purification section (E), possibly after fractionation and / or dilution, could be used as is or sent to one or more of the optional sections S-Pool, S-HDT, S-HC, S-Vapo, S-FCC, as shown in Figure 1.

[0252] Alternatively or in combination, the effluent (6) leaving the separation section (D), possibly after fractionation and / or dilution, could be used as is or sent to one or more of the optional sections S-Pool, S-HDT, S-HC, S-Vapo, S-FCC, as shown in Figure 1. Examples

[0253] Example 1

[0254] A HPP1 plastic oil was subjected to hydrotreatment followed by basic treatment.

[0255] Table 1 lists the hydrotreatment conditions. The final temperature is around 120°C.

[0256] Table 1

[0257] Hydrotreatment was carried out on 50 mL of catalyst (Ni on extruded alumina) diluted with 100 mL of SiC (0.21 mm). Activation of the catalyst consisted of reduction under dihydrogen followed by inerting under N2. The catalyst was then stabilized (passage under inert load without sulfur with dihydrogen in the operating conditions of the test (P, T, LHSV, H2 / HC).

[0258] The load to be tested was then introduced under the start of test conditions (SOR), then the temperature was increased first in steps of 20 °C at a rate of 2 °C / h, then in steps of 10 °C at a rate of 2 °C / h when approaching the target temperature, until the highest conversion of the double bonds was obtained (i.e. the lowest Diene value DV, or a DV < 1 gl2 / 100g, ideally 0.5 gl2 / 100g). This "diene value" is measured by FTIR spectrometer with a calibration point made on the load by determination of the diene value by titration.

[0259] The hydrotreatment was carried out for 7 days. Each day, a sample was taken and the diene value (DV) and bromine number were measured. The results are summarized in Table 2.

[0260] Table 2

[0261] At the end of the hydrotreatment, the samples and the remaining reaction medium were combined to recover the hydrotreated oil (denoted hydrotreated HPP1) which was then treated with soda under the conditions shown in Table 3, then washed according to the procedure described below.

[0262] The hydrotreated effluent is introduced into a 1.5 L AISI-316L grade stainless steel autoclave equipped with mechanical stirring. The sum of the volume of hydrotreated effluent and 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 under N2 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 and maintained at the target temperature for a period of 30 minutes. The temperature rise rate is set at 30 °C / 10 minutes.

[0263] At the end of the reaction, the autoclave was cooled to room temperature and then the mixture was discharged and washed three times with water, each time using a water / feed volume ratio of 40 / 60, to remove strong base residues and water-soluble impurities. The resulting purified and washed hydrotreated effluent was analyzed to measure the residual impurity content. These results are presented in Table 4, which shows the results of the comparative analyses of the hydrotreated effluent before and after soda treatment and washing.

[0264] Table 3

[0265] Table 4 Furthermore, a simulated distillation test showed that the oil distillation curve is almost not affected by the treatment.

[0266] Example 2

[0267] An HPP2 plastic oil was subjected to hydrotreatment followed by basic treatment. The hydrotreatment conditions are listed in Table 5. In this test, 20 ml of NiMo catalyst on alumina in extruded form with 0.1 mm SiC in a mixture of 1 to 2% vol. were used. The catalyst was then sulfurized using a sulfurized charge, then stabilized by passing under an inert charge under the operating conditions of the test (P, T, LHSV, H2 / HC). The test was then carried out according to the same procedure as Example 1 but over 10 days with one sample per day.

[0268] Table 5

[0269] The results of diene monitoring during hydrotreatment are presented in Table 6.

[0270] Table 6: At the end of the hydrotreatment, the samples and the remaining reaction medium were combined to form the hydrotreated oil (denoted hydrotreated HPP2). The diene index measured for this hydrotreated oil is 0.3 gl2 / 100 g.

[0271] The hydrotreated oil was then treated with soda under the conditions given in Table 7, then washed, using the same procedure as that described in Example 1.

[0272] Table 7

[0273] The results of comparative analyses of HPP2 oil before and after soda treatment and washing are presented in Table 8

[0274] Table 8

[0275] As in Example 1, a simulated distillation test showed that the distillation curve of the oil is almost not affected by the treatment. Examples 1 and 2 thus show that the sequence of steps b) to d) of the invention makes it possible to eliminate the dienes while obtaining good reductions in oxygen, nitrogen, silicon and chlorine, while preserving the distillation curve of the initial product.

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, a diene number of at least 0.5 g l2 / 100g measured according to LIOP326 and a bromine number of at least 5 g Br2 / 100g measured according to ASTM D1159, (b) subjecting the composition of step (a) to a first hydrotreatment step to obtain a hydrotreated composition forming a first effluent having a reduced diene index, the first hydrotreatment step being carried out at a temperature of at most 250°C in the presence of dihydrogen and at least one hydrotreatment catalyst, (c) contacting the first effluent with a basic compound at a temperature of 100 to 350°C to obtain a modified hydrotreated composition forming a second effluent, (d) subjecting the second effluent to at least one step chosen from (d1) washing with water or a solvent immiscible with the second effluent, (d2) separation by (i) filtration, (ii) centrifugation, (iii) hydrocyclone, (iv) decantation, (v) distillation or (vi) a combination of two or more of these steps, and separately recovering a purified composition forming a third effluent having a reduced heteroatom content and a phase containing the basic compound and heteroatoms initially contained in the second effluent, (f) optionally subjecting the third effluent to a second hydrotreatment step to obtain a fourth effluent, the second hydrotreatment step being carried out at a temperature of at least 200°C in the presence of dihydrogen and at least one hydrotreatment catalyst.

2. Method according to claim 1, characterized in that said composition provided in step (a) comprises at least one of the following characteristics: - said composition contains at least 10% by weight of plastic liquefaction oil, the other part of said composition being a diluent or said composition contains only plastic liquefaction oil, - said plastic liquefaction oil in said composition has an initial boiling point of at least 15°C and a final boiling point of at most 700°C, preferably at most 600°C, more preferably 560°C, preferably 450°C, more preferably 350°C, preferably 250°C, - said plastic liquefaction oil has a diene index of at most 50 gl2 / 100 g, preferably at most 25 gh / 100 g, more preferably at most 10 gh / 100 g, measured according to standard UOP 326, - said plastic liquefaction oil contains more than 2 ppm by weight of metals, - said plastic liquefaction oil contains at least 5 ppm by weight of Si, preferably at most 5000 ppm by weight of Si, and / or at least 1 ppm by weight of Si, preferably at most 5000 ppm by weight of Si, and / or at least 1 ppm by weight of Si, preferably at most 1000 ppm by weight of Si, and / or at least 1 ppm by weight of Cl, preferably at most 5000 ppm by weight, and / or at least 1 ppm by weight of P, preferably at most 5000 ppm by weight relative to the total weight of said plastic liquefaction oil.

3. Method according to claim 1 or 2, characterized in that step (b) comprises one or more of the following characteristics: - prior to step (b), the composition provided in step (a) is subjected to (i) filtration, (ii) washing with water or a polar solvent immiscible with the composition, (iii) distillation, (iv) decantation, (v) a hydrocyclone or (vi) the combination of at least two steps (i) to (iv), - the inlet temperature is 25 to 250°C, preferably 130 to 250°C, - the absolute pressure is from 5 to 90 bar, preferably from 10-50, more preferably from 25-50 bar in the presence of H2 and / or the molar ratio of H2 to the total molar sum of alkynes and dienes in said composition is from at least 1.5, preferably from at least 2, preferably from at least 3, to at most 15, - said first hydrotreatment step comprises one or more catalytic beds with, preferably, an overall increase in temperature of at most 150°C, preferably at most 100°C, and / or an increase in temperature of at most 100°C, preferably at most 50°C for each catalytic bed, with, preferably, an intermediate quench between said catalytic beds, said quenching preferably being carried out with H 2 or with the fourth effluent recovered in step (f); - this first step is carried out in a fixed bed reactor, preferably in the presence of at least one catalyst comprising at least one metal from groups 8-10, preferably chosen from the group Pt, Pd, Ni and / or their mixture on a support such as alumina, titanium, silica, zirconia, magnesia, carbon and / or their mixtures; preferably, this catalyst is a Ni-based catalyst passivated after its reduction preferably using a di-alkyl-sulfide such as DiMethylSulfide (DMS) or DiMethylDiSulfide (DMDS) or DiEthylSulfide (DES), or thiophenic compounds; - this first step is carried out in a fixed bed reactor, preferably in the presence of at least one catalyst comprising at least one metal from group 6, such as for example Mo, W, in combination or not with a promoter chosen from at least one metal from groups 8-10, such as for example Ni and / or Co, and / or a mixture thereof, these metals being used in sulphide form and preferably supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof; - the first effluent has a diene index of at most 1.5 g / 100 g, preferably at most 1.0 g I2 / 100 g, more preferably at most 0.5 g I2 / 100 g - in said composition, at least 10% by weight, preferably at least 15% by weight, preferably at least 25% by weight, more preferably at least 50% by weight of said composition has a boiling point of at least 150°C relative to the total weight of said composition.

4. A method according to any one of claims 1 to 3, wherein step (c) comprises one or more of the following features: - prior to step (c), the first effluent is subjected to flash distillation in order to eliminate at least part of the gaseous phase which it contains, - prior to step (c) or during step (c), the following is added to the first effluent: (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, - step c) is carried out in the presence of 0.1 to 50% m of basic compound relative to the total mass of said first effluent, - 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, Na2O, KOH, K2O, CaO, Ca(OH)2, MgO, Mg(OH)2, NH4OH, TMAOH, TEAOH, TBuOH, MeONa, EtONa and their mixtures, - step c) is carried out at a temperature of 180 to 300°C, - step c) is carried out for a period of 0.1 seconds to 3 hours, preferably 1 minute to 1 hour, more preferably 1 minute to 30 minutes.

5. Method according to any one of claims 1 to 4, characterized in that step (d) comprises at least one of the following characteristics: - step d1) 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 second effluent, preferably in the presence of water, - step (d) comprises at least the separation step (d2) for separating the phase containing the basic compound and the third effluent, and optionally the phase containing the basic compound is returned in whole or in part to step (c).

6. Method according to any one of claims 1 to 5, characterized in that, after step (d), optionally prior to step (f), the third effluent is (e) 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.

7. Method according to any one of claims 1 to 6, characterized in that step (f) comprises at least one of the following characteristics: - after this second hydrotreatment step, the olefin concentration, measured by the bromine index in the fourth effluent, is at most 5.0 gBr2 / 100g, preferably at most 2.0 gBr2 / 100g, preferably at most 1.5 gBr2 / 100g, more preferably at most 0.5 gBr2 / 100g, as measured according to ASTM D1159, - this second hydrotreatment stage comprises one or more catalytic beds with, preferably, an overall increase in temperature of at most 100°C, and / or an increase in temperature of at most 50°C on each catalytic bed, with, preferably, an intermediate quench between said catalytic beds, said quenching preferably being carried out with H2 or with said stream of purified hydrocarbons recovered in step f); - the inlet temperature is at least 200°C, preferably 230°C, more preferably 250°C and at most 500°C; the WH is 1 to 10h' 1 , preferably 2 to 4 hours1 ; - the absolute pressure is 10 to 160 bar in the presence of H2; - said second hydrotreatment step is carried out in the presence of at least one catalyst which comprises at least one metal from group 6 such as for example Mo, W in combination or not with a promoter chosen from at least one metal from groups 8-10 such as for example Ni and / or Co, and / or a mixture thereof, these metals preferably being used in sulphurized form and supported on alumina, titanium, zirconia, silica, carbon and / or mixtures thereof; - the ^ / hydrocarbons ratio is from 200 NL / L to 900 NL / L, preferably in the presence of at least 0.005% by weight, preferably 0.05% by weight, more preferably 0.5% by weight of sulfur, preferably H2S or organic sulfur compounds, in the stream; - at the top of the second hydrotreatment stage, a silicon trap is present, working at a temperature of at least 200°C, and / or at a WH of 1 to 10h-1 , and / or at an absolute pressure of 10 to 160 bar in the presence of H2; possibly with a metal trap working at a temperature of at least 200°C, at a WH of 1 to 10h' 1 , at an absolute pressure of 10 to 160 bar in the presence of H2.

8. A process according to any one of claims 1 to 7, wherein, before carrying out the first and / or second hydrotreatment, a dilution is carried out using a diluent, said diluent preferably being a hydrocarbon stream having a boiling range of 50°C to 150°C or a boiling range of 150°C to 250°C or a boiling range of 200°C to 350°C, or the effluent of said first and / or said second hydrotreatment or any mixture thereof;preferably, said diluent is added at a concentration of at most 80% by weight, preferably at most 50% by weight and, optionally, said diluent is separated at the outlet of said first and / or said second hydrotreatment by distillation, for example by flash distillation, and, preferably, recycled to the inlet of said first and / or said second hydrotreatment and / or said diluent preferably has a bromine index of at most 5 gBr2 / 100g, and / or a diene index of at most 0.5 gl2 / 100g and / or a sulfur content of at most 1000 ppm by weight.; 9. A process according to any one of claims 1 to 8, wherein the fourth effluent leaving step (f) is washed to remove inorganic compounds.

10. Process according to any one of claims 1 to 9, in which the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, is used as is 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.

11. Process according to any one of claims 1 to 9, in which the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, is subjected, pure or diluted, optionally after separation into usable streams, to a steam cracking step to produce olefins such as ethylene and propylene, which can then be used to manufacture new polymers by polymerization.

12. Process according to any one of claims 1 to 9, in which the third effluent leaving step (d), optionally purified by passing over a solid adsorbent, or the fourth effluent leaving step (f), optionally washed, is treated, pure or diluted, optionally after separation into usable streams, in a steam cracker to produce olefins, and / or a fluidized bed catalytic cracker, and / or a hydrocracker, then optionally in a steam cracker, and / or a hydrotreatment reactor, in particular a catalytic hydrogenation reactor.

13. A method according to any one of the preceding claims wherein step a) comprises: a1) a step of providing a stream of plastic or plastic-containing waste; a2) a step of liquefying this waste at a temperature of at least 200°C, and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase; a3) a step of recovering said hydrocarbon product and separating the liquid phase from said product, said liquid phase forming a plastic liquefaction oil; a4) an optional step of mixing the plastic liquefaction oil with a diluent or a solvent.

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