Process for the production of paraffins by hydrotreatment of feedstocks from plastic waste

Abstract

The present invention relates to a process for the production of paraffins by hydrotreatment, in particular from a composition comprising a plastic liquefaction oil, said composition comprising paraffins, olefins, aromatics and heteroatoms. The process comprises: (a) a step of separating a portion of the paraffins and olefins contained in said composition, comprising at least one step of crystallizing (i) the composition by lowering the temperature by 10°C to 60°C from an initial temperature at which the composition is entirely liquid, and obtaining a mixture comprising a paraffin-enriched solid product depleted of olefins, aromatics and heteroatoms and a paraffin-depleted effluent enriched in olefins, aromatics and heteroatoms, followed by at least one step of separating (ii) said solid product and said effluent, (b) a step of hydrotreating the solid product of step (a), during which hydrotreatment step the olefins contained in the solid product are hydrogenated and an effluent containing paraffins and a maximum of 2% w / w of olefins is produced.

Description

[0001] TITLE: PROCESS FOR THE PRODUCTION OF PARAFFINS BY HYDROTREATMENT OF FEEDSTOCKS FROM PLASTIC WASTE

[0002] Technical field

[0003] The present invention relates to a process for producing paraffins, and in particular waxes, by hydrotreatment, in particular from feedstocks originating from plastic waste.

[0004] Background to the invention

[0005] Paraffins, especially waxes, are most often obtained by refining fossil hydrocarbons.

[0006] Waxes are primarily mixtures of linear or branched paraffins (n- and iso-alkanes) whose carbon chain generally contains more than 18 carbon atoms, and potentially up to more than 100 carbon atoms. The melting points of paraffins increase with the carbon number. For C18+ paraffins, this melting point (measured according to ASTM D87:2009) is generally above 25°C, and is typically above 70°C for paraffins used as waxes.

[0007] Waxes are mainly used, pure or in mixtures with additives, for coating paper, cardboard, containers, metals, etc. (waterproofing or protection), for thermal insulation, for the manufacture of candles (flash point between 200°C and 250°C), in mixtures with chemical products, for the manufacture of chlorinated paraffins, for the waterproofing of fabrics, for the waterproofing of particle boards, etc.

[0008] With the scarcity of fossil resources and growing environmental constraints, manufacturers are looking for other hydrocarbon feedstocks to produce paraffins and particularly waxes.

[0009] Furthermore, the significant quantities of plastic waste produced and the environmental problems they generate have led manufacturers to seek ways to recycle this waste, in particular those allowing the production of new monomers and then polymers and thus closing the life cycle of plastic. This recycling route is a chemical route consisting of liquefying plastic waste, in particular by thermal means (typically by pyrolysis or hydrothermal liquefaction), then reintroducing the effluent produced into a conventional refining circuit. This liquefaction is however energy-intensive and is therefore only considered for treating contaminated plastic waste, which cannot be treated in another way (by mechanical recycling or depolymerization for example).

[0010] The significant amount of impurities present in plastic waste liquefaction oils requires pretreatment before injection into a conventional refining circuit. Thus, pyrolysis or hydrothermal liquefaction of plastic waste is typically followed by purification including hydrotreatment and removal of contaminants using various purification processes such as distillation.

[0011] There are many pretreatment processes focused on removing chlorinated compounds. However, other impurities present in plastic liquefaction oil simply prohibit their direct use in other refining processes. In particular, oxygenated compounds present in plastic liquefaction oil can be converted to peroxides and thus promote the formation of polymers and gums from the olefins present in the plastic liquefaction oil. In particular, the presence of olefins and oxygenated compounds can lead to undesirable polymerization during storage, transport from the production site to the further processing site, as well as during purification and further processing. Since purification operations are often carried out at elevated temperatures, an increase in the undesirable polymerization rate can thus be observed.

[0012] WO2021 / 115982 describes a process for the dewaxing recovery of aliphatic hydrocarbons from a hydrocarbon feedstock comprising aliphatic hydrocarbons and polar compounds containing a heteroatom. This feedstock includes liquid products from the pyrolysis of plastic waste. The process described involves mixing the feedstock to be treated with a solvent, cooling the mixture in a temperature range of 5°C to -30°C to obtain wax crystals, and separating them to produce aliphatic hydrocarbons comprising wax and a dewaxed liquid comprising the solvent, polar compounds, and optionally aromatics. This document provides for steam cracking of the aliphatic hydrocarbons comprising wax directly, without intermediate hydrotreatment. These aliphatic hydrocarbons are defined as non-olefinic (paraffinic) aliphatic compounds and olefinic aliphatic compounds.The production of paraffins is not described.

[0013] Furthermore, the behavior of plastic waste liquefaction oils is difficult to predict due to the complexity of these oils. For example, gas chromatographic analysis of plastic waste pyrolysis oil can only identify 25 to 45% by weight of compounds containing oxygen and nitrogen. In addition, the composition of these oils varies greatly depending on the nature of the plastic waste being treated.

[0014] There is therefore a continuing need to develop methods to produce high-value chemicals from plastic waste, regardless of its origin, particularly by using existing conventional refining units.

[0015] Summary of the invention

[0016] The invention aims to provide a process for producing paraffins, and in particular waxes, by hydrotreatment from a composition comprising a plastic liquefaction oil, said composition comprising paraffins, olefins, aromatics and heteroatoms, the process comprising:

[0017] (a) a step of separating a portion of the paraffins and olefins contained in said composition comprising at least one step of crystallization (i) of said composition by lowering the temperature from 10°C to 60°C from an initial temperature at which said composition is entirely liquid and obtaining a mixture comprising a solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms, and an effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms, followed by at least one step of separation (ii) of said solid product and said effluent,

[0018] (b) a step of hydrotreating the solid product of step (a) during which the olefins contained in said solid product are hydrogenated and an effluent is produced containing paraffins and at most 2% m / m of olefins. This particular sequence of steps makes it possible to treat in a hydrotreatment reactor a solid resulting from a composition comprising a plastic liquefaction oil but having olefin, aromatic and heteroatom contents conforming to those required at the inlet of a hydrotreatment reactor process, regardless of the contaminant content of the composition.

[0019] The process according to the invention makes it possible in particular to produce paraffins, and in particular waxes, from compositions containing C5-C150 hydrocarbons, most often C5-C100. In particular, the separation step (a) can be implemented to separate the paraffins from the olefins present in compositions containing hydrocarbons without limitation as to the number of carbon atoms constituting them.

[0020] The composition treated by the process according to the invention may comprise at least 2% by mass of plastic liquefaction oil(s). The remainder may then be composed of at most 98% by mass of a diluent or solvent such as a hydrocarbon and / or one or more components such as: a biomass liquefaction oil such as Panicum virgatum, a tall oil, a used edible oil, an animal fat, a vegetable oil such as rapeseed, canola, castor, palm, soybean oil, an oil extracted from an algae, an oil extracted from a fermentation of oleaginous microorganisms such as oleaginous yeasts, a biomass liquefaction oil such as a lignocellulosic biomass such as a wood, paper and / or cardboard liquefaction oil, an oil obtained by pyrolysis of crushed used furniture, an elastomer liquefaction oil for example possibly vulcanized latex or tires, as well as mixtures thereof.

[0021] In one embodiment, the composition may comprise at least 5% by mass, at least 10% by mass, at least 25% by mass, at least 50% by mass, at least 75% by mass, at least 90% by mass or 100% by mass of plastic liquefaction oil(s). The mass content of plastic liquefaction oil(s) in the composition may be within any range defined by two of the previously set limits.

[0022] The heteroatoms contained in the composition treated in the present invention may be oxygen, nitrogen, sulfur, silicon, a metal and / or a halogen, in particular chlorine. The solid product resulting from step (a) may contain from 45% m / m to 90% m / m of paraffins, preferably from 50% m / m to 90% m / m of paraffins, from 10 to 50% m / m of olefins, preferably from 10 to 40% m / m of olefins, from 0 to 2% m / m of aromatics, from 2 to 15% m / m of naphthenes, and optionally at most 2% m / m of heteroatoms.

[0023] In particular, step (a) can make it possible to eliminate at least 80% m / m of chlorine and / or at least 85% m / m of nitrogen and / or at least 50% m / m of sulfur and / or at least 60% m / m of silicon relative to the respective quantities of chlorine, nitrogen, sodium and silicon initially present in the composition entering into the process according to the invention.

[0024] The paraffins produced in step (b), more precisely the effluent from step (b) containing the paraffins, may contain from 0 to 2% m / m of olefins, preferably from 0 to 1% m / m. The total heteroatom content may be from 0 to 1% m / m. Thus, the effluent produced in step (b) may contain 70% m / m or more of paraffins, preferably 80% m / m or more of paraffins, more preferably 90% m / m or more of paraffins, in particular 97% m / m or more of paraffins, preferably 98% m / m or more of paraffins.

[0025] The effluent from step (b) may advantageously contain C18+ paraffins, for example C18-C100 paraffins, namely waxes.

[0026] Advantageously, the paraffins produced in step (b), more precisely the effluent from step (b) containing the paraffins, may also contain:

[0027] - at most 100 ppm of oxygen (measured according to ASTM D5622 / D2504),

[0028] - not more than 20 ppm of nitrogen (measured according to ASTM D4629),

[0029] - at most 500 ppm of sulfur (measured according to ISO 20846),

[0030] - not more than 120 ppm of chlorine (measured according to ASTM D7359-18),

[0031] - optionally at most 15 ppm of silicon (measured by XRF).

[0032] In one embodiment, during separation step (a), said composition may be mixed with at least one solvent prior to at least one crystallization step (i). It will then be possible to advantageously provide a step of separating the at least one solvent from the effluent resulting from separation step (iii) and returning the at least one solvent separated in step (i). The solvent may advantageously be an organic solvent, for example chosen from an aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone, an alcohol or their mixtures, preferably a ketone or an alcohol. Examples of solvents that can be used include acetone, methyl ethyl ketone, isopropanol.

[0033] In particular, a solvent or a mixture of solvents may be chosen which does not crystallize at the crystallization temperature of the paraffins to be separated, preferably a solvent or a mixture of solvents in the liquid state and miscible with the composition at the temperatures for implementing step (a) of the process of the present invention and in particular of the at least one crystallization step (i). A person skilled in the art will be able to determine the most appropriate solvent or mixture of solvents depending on the temperatures used during step (a) by tests and / or simulations. In particular, when the feedstock to be treated is solid and / or very viscous, it may be necessary to heat the feedstock to reach the initial temperature before lowering the temperature from 10 to 60°C: a solvent or mixture of solvents will then be chosen which remains liquid at these temperatures.

[0034] The volume ratio of said composition to the solvent may be from 10 / 90v / v to 90 / 10v / v, or from 20 / 80v / v to 80 / 20v / v, preferably from 40 / 60v / v to 60 / 40v / v or from 45 / 55v / v to 55 / 45v / v, for example 50 / 50v / v, or in any interval defined by two of these ratios.

[0035] Separation step (a) can be carried out in a single step or in two steps to improve the separation and recovery of paraffins. Separation step (a) can then comprise:

[0036] (i-1) a first crystallization step by lowering the temperature of said composition from 10°C to 60°C from a first initial temperature at which said composition is entirely liquid and obtaining a first mixture comprising a first solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms, and a first effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms,

[0037] (ii-1) a first step of separating said first solid product and said first effluent, (i-2) a second step of crystallization by lowering the temperature of said first effluent from 10°C to 60°C from a second initial temperature at which said first effluent is entirely liquid and obtaining a second mixture comprising a second solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms, and a second effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms.

[0038] (ii-2) a second step of separating said second solid product and said second effluent, and the first solid product and the second solid product are subjected to step (b) of hydrotreatment.

[0039] When a solvent or mixture of solvents is added to the composition, it is then added before the first crystallization step (i-1). Preferably, no solvent is added before the second crystallization step (i-2).

[0040] Crystallization step (i) or each of crystallization steps (i-1) and (i-2) is carried out from an initial temperature at which the composition (alone or in a mixture with a solvent), or the first effluent, is entirely liquid, up to a final temperature, 10 to 60°C lower than the initial temperature.

[0041] The initial temperature of step (i) or of each of steps (i-1) and (i-2) can be easily determined by a person skilled in the art using standard measuring methods. The initial temperature is typically higher (for example by 5 to 10°C) than the crystallization temperature of the paraffins to be separated from the composition. This crystallization temperature can be determined by differential scanning calorimetry measurements (P. CIaudy et al, Diesel fuels: determination of onset crystallization temperature, pour point and filter plugging point by differential scanning calorimetry. Correlation with standard test methods. Fuel, 1986, vol 65, pp 861-4).

[0042] Step (a) can advantageously be carried out under conditions suitable for separating C18+ paraffins, for example C18-C100 paraffins, namely waxes. These conditions include the final temperature of step (i) or of each of steps (i-1) and (i-2) mentioned above, typically lower than the melting temperature of the paraffins of interest, and optionally the cooling rate and / or the quantity of solvent used. The conditions for separating the paraffins of interest can be easily determined by a person skilled in the art by tests and / or simulations.

[0043] During separation step (a), separation step (ii), (ii-1) or (ii-2) may be carried out by at least one step chosen from filtration, decantation, centrifugation. This separation step (ii), (ii-1) or (ii-2) is typically carried out at a temperature lower than or equal to the final temperature of step (i), (i-1) or (i-2) in order to recover the solid product.

[0044] In one embodiment, the solid product from step (a), before being hydrotreated in step (b), may be washed, in one or more times, typically three times, with at least one solvent, preferably at a temperature lower than or equal to the final temperature. This solvent is as defined above. When at least one solvent is used during the crystallization step (i), (i-1) or (i-2), the same solvent or mixture of solvents may advantageously be used for this washing step. This washing step may advantageously be followed by a step of drying or evaporation of the washed solid product, making it possible to remove the residual solvent(s) before the hydrotreatment (b).

[0045] During the hydrotreatment of step (b), 98% m / m or more of the olefins can be hydrogenated, in particular by choosing suitable operating conditions.

[0046] The effluent from step (b) may advantageously contain 70% m / m or more of C18+ paraffins, for example C18-C100 paraffins, namely waxes, preferably 80% m / m or more of these paraffins, more preferably 90% m / m or more of these paraffins, in particular 97% m / m or more of these paraffins, preferably 98% m / m or more of these paraffins.

[0047] The hydrotreatment of step (b) can be carried out in a single step or in two steps. When carried out in a single step, the solid product(s) from step (a) are hydrogenated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bar, preferably 30 to 100 bar and in the presence of a hydrotreatment catalyst, for example a hydrogenation catalyst comprising NiMo (0.1-60% by mass) and / or CoMo (0.1-60% by mass). Alternatively, the hydrotreatment of step (b) can be carried out in a first step (b-1) in which the solid product(s) from step (a) are hydrogenated at a temperature of 80 to 250°C, preferably 130 to 190°C in the presence of hydrogen at an absolute pressure of 5 to 60 bars, preferably 20 to 30 bars and in the presence of a first hydrotreatment catalyst, for example a hydrogenation catalyst comprising Pd (0.1 -10% by weight) and / or Ni (0.1 -60% by weight) and / or NiMo (0.1 -60% by weight), and in a second step (b-2) in which the effluent from step (b-1) is hydrogenated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a second hydrotreatment catalyst, for example a hydrogenation catalyst comprising NiMo (0.1 -60% by weight) and / or CoMo (0.1-60% by weight). The first step can then make it possible to hydrogenate dienes initially present in the composition and which have been crystallized with the paraffins in the solid product(s).

[0048] The invention also relates to a process for recovering plastic waste comprising the following steps:

[0049] (A) a step of liquefying waste containing plastics and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase,

[0050] (B) a step of separating the liquid phase from said product, said liquid phase forming a plastic liquefaction oil,

[0051] (C) a step of treating at least part of the liquid phase by a process for producing paraffins according to the invention.

[0052] The liquefaction step (A) may comprise a pyrolysis step typically carried out at a temperature of 300 to 1000°C or 400 to 700°C, this pyrolysis being for example a rapid pyrolysis, a flash pyrolysis, or a catalytic pyrolysis or a hydropyrolysis.

[0053] Alternatively or in combination, the liquefaction step (A) 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.

[0054] The waste treated in step (A) may be plastic waste possibly mixed with biomass, as previously described. The separation step (B) eliminates the gaseous phase, essentially C1-C4 hydrocarbons and the solid phase (typically char) to recover only the liquid organic phase forming a liquefaction oil.

[0055] This plastic liquefaction oil typically comprises 30 to 55% by mass of paraffins, 10 to 50% m / m of olefins, 5 to 12% m / m of aromatics. These contents can be determined by gas chromatography.

[0056] In particular, a plastic liquefaction oil may include a Bromine index of 20 to 60 g Br / 100 g and / or a maleic anhydride index (UOP326-82) of 1 to 20 mg maleic anhydride / 1 g.

[0057] A plastic liquefaction oil may include, but is not limited to, one or more of the following heteroatom contents: 0 to 8% w / w oxygen (measured according to ASTM D5622), 1 to 13000 ppm nitrogen (measured according to ASTM D4629), 2 to 10000 ppm sulfur (measured according to ISO 20846), 1 to 10000 ppm metals (measured by ICP), 50 to 6000 ppm chlorine (measured according to ASTM D7359-18), 0 to 200 ppm bromine (measured according to ASTM D7359-18), 1 to 40 ppm fluorine (measured according to ASTM D7359-18), 1 to 2000 ppm silicon (measured by XRF).

[0058] A plastic liquefaction oil may in particular comprise one or more of the following heteroatom contents: from 0 to 8% m / m of oxygen, from 250 to 3800 ppm of nitrogen, from 35 to 850 ppm of sulfur, from 34 to 900 ppm of metals, from 50 to 6000 ppm of chlorine, from 0 to 10 ppm of bromine, from 1.5 to 10 ppm of fluorine.

[0059] This liquid phase can then be subjected, in part (in particular a fraction of it) or in its entirety, to the paraffin production process of the invention, alone or in a mixture with other components as previously described to produce the paraffins of interest by hydrotreatment.

[0060] In particular, a fraction of this liquid phase, corresponding for example to a naphtha or diesel cut, alone or in a mixture with other components as previously described, may be subjected to the paraffin production process according to the invention.

[0061] Advantageously, the composition treated in the present invention may have at least 50% m / m of paraffins and olefins, in particular C5-C150 paraffins and olefins, most often C5-C100, preferably at least 55% m / m, 60% m / m or 65% m / m of paraffins and olefins, and / or at most 95% m / m, 90% m / m, 85% m / m or 80% m / m of paraffins and olefins. The content of paraffins and olefins, in particular C5-C150 paraffins and olefins, most often C5-C100, of the treated composition may be included in any range defined by two of these limits.

[0062] Definitions

[0063] 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.

[0064] The expressions % by weight and % by mass have an equivalent meaning and refer to the proportion of the mass of a product relative to 100g of a composition comprising it.

[0065] The expression "plastic liquefaction oil" or "oil resulting from the liquefaction of plastic" or "plastic waste liquefaction oil" or "liquefaction oil resulting from the liquefaction of waste containing plastics" refers to the liquid products obtained following pyrolysis or hydrothermal liquefaction of thermoplastic, thermosetting or elastomeric polymers, alone or in a mixture and generally in the form of waste, optionally in a mixture with at least one other waste such as biomass, for example chosen from lignocellulosic biomass, paper and cardboard.

[0066] The pyrolysis process should be understood as a thermal cracking process, carried out in the presence or absence of a catalyst (for example, catalytic or non-catalytic fast pyrolysis, etc.). The hydrothermal liquefaction process (or HTL for "Hydrothermal Liquefaction" in English) is a thermochemical conversion process using water as a solvent, reactant and catalyst for the degradation reactions of plastics or biomass, the water typically being in a subcritical or supercritical state.

[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 halogenated polyethylene (Cl, F) or not, polypropylene, polystyrene, polybutadiene, polyisoprene, poly(ethylene terephthalate) (PET), acrylonitrile-butadiene-styrene (ABS), polybutylene, poly(butylene terephthalate) (PBT), polyvinyl chloride (PVC), polyvinylidene chloride, a polyester, a polyamide, a polycarbonate, a polyether, an epoxy polymer, a polyacetal, a polyimide, a polyesteramide, silicone etc. In general, any polymer or mixture of polymers capable of producing paraffins by liquefaction can be used.

[0068] These plastic liquefaction oils contain paraffins, i-paraffins (isoparaffins), dienes, alkynes, olefins, naphthenes, and aromatics. Plastic liquefaction oils also contain heteroatom-containing impurities, such as chlorinated, oxygenated, and / or silylated organic compounds, metals, salts, phosphorus, sulfur, and nitrogen compounds.

[0069] The composition of plastic liquefaction oil depends on the nature of the liquefied plastic and is essentially (notably more than 80% m / m, most often more than 90% m / m) made up of hydrocarbons having 1 to 150 carbon atoms and impurities.

[0070] 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 liquefaction oil treated by the invention may originate from the liquefaction of waste containing at least 1% m / m, optionally from 1 to 50% m / m, from 2 to 30% m / m or in a range defined by any two of these limits, of one or more of the aforementioned biomasses, residues and organic waste, and the remainder consisting of plastic waste.

[0071] The composition of plastic liquefaction oil depends on the nature of the liquefied plastic and is essentially (notably more than 80% m / m, most often more than 90% m / m) made up of hydrocarbons having 1 to 150 carbon atoms and impurities.

[0072] The term "MAV" (acronym for "Maleic Anhydric Value") refers to the UOP326-82 method which is expressed in mg of maleic anhydride which react with 1 g of sample to be measured.

[0073] The term "Bromine Index" is the number of milligrams of bromine that react with 100 g of sample and can be measured according to ASTM D1159-07 (2017).

[0074] Metal concentrations in hydrocarbon matrices can be determined by any known method. Acceptable methods include X-ray fluorescence (XRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Analytical scientists know how to identify the most appropriate method for measuring each metal and heteroelement based on the hydrocarbon matrix under consideration.

[0075] The content of paraffins, olefins, naphthenes and aromatic hydrocarbons can be determined by multidimensional gas chromatography, for example according to the method described in Duhamel, Journal of Chromatography A, 1387 (2015) 95-103, Comparison of cryogenic and differential flow modulator.

[0076] The melting point of paraffins can be measured according to ASTM D87:2009.

[0077] Oxygen content can be measured according to the standard: ASTM D5622-17 / D2504-88(2015). Nitrogen content can be measured according to the standard: ASTM D4629-17. Sulfur content can be measured according to ISO 20846:2011. Halogen content, including chlorine, bromine, fluorine, can be measured according to the standard: ASTM D7359-18. Silicon content can be measured by XRF.

[0078] 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.

[0079] 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.

[0080] Description of the invention

[0081] Figure 1 shows the GC-MS spectra of the products of Example 3.

[0082] Examples

[0083] Embodiments of the present invention are illustrated by the following non-limiting examples.

[0084] Example 1: Separation of paraffins by crystallization in acetone or in an acetone-isopropanol mixture

[0085] A plastic pyrolysis oil HPP1 was mixed at room temperature (i.e. approximately 10°C above the crystallization temperature of the paraffins to be separated) (T° = 25°C, P = 1 atm) with a crystallization solvent (acetone or a 50 / 50 (v / v) mixture of acetone and isopropanol) to produce a clear, homogeneous solution. The temperature of the mixture was then lowered from this initial temperature of 25°C to a final temperature of -20°C. The formation of a solid product (called cake) was observed. The cake was separated by filtration, washed with the crystallization solvent, then dried and analyzed.

[0086] Table 1 lists the compositions of the pyrolysis oil and the cakes from the two filtrations. It can be seen that the recovered solid product contains mainly paraffins, with a significant amount of olefins and a very small amount of aromatics.

[0087] In addition, a reduction of more than 80% m / m of Cl, more than 85% m / m of nitrogen, more than 50% m / m of sulfur and more than 60% m / m of Si initially present in the HPPI could be determined. Table 1

[0088] (*): includes linear and branched olefins, linear and branched diolefins, saturated naphthenes.

[0089] Example 2: separation of paraffins by crystallization in acetone or in an acetone-isopropanol mixture

[0090] A HPPT plastic pyrolysis oil was subjected to the same treatment as described in Example 1 and a cake (denoted T cake) was recovered.

[0091] Tables 2 and 3 give the compositions of HPPT oil and T-cake, respectively. HPPT oil and T-cake were analyzed by GCxGC-FID using a two-dimensional GCxGC chromatograph equipped with a non-polar capillary column in the first dimension (1 D) and a capillary column of intermediate polarity in the second dimension (2 D). Detection is performed by a flame ionization detector (FID).

[0092] A first separation on the 1D column separates the compounds according to their boiling points. They are periodically trapped in the modulation loop and injected into a second column which separates the compounds according to their polarities. The chromatogram obtained is demodulated in the form of a two-dimensional retention plane and exploited via dedicated software (e.g. GC Image). Quantification of the compounds is carried out by normalizing to 100% the compounds detected by the FID. In Tables 2 and 3, the n-olefin contents include the contents of n-olefins and n-diolefins.

[0093] Table 2 Table 3 Example 3: Separation of paraffins by crystallization in acetone

[0094] A diesel fraction of plastic pyrolysis oil was dewaxed by crystallization. This diesel fraction, denoted "diesel ex HPP", consists of C10-C30 hydrocarbons and contains 49.55% m / m of paraffins and 41.30% m / m of olefins.

[0095] The diesel fraction was mixed at room temperature (i.e. approximately 10°C above the crystallization temperature of the paraffins to be separated) (T° = 25°C, P = 1 atm) with acetone (volume ratio diesel ex HPP / acetone of 50:50) to produce a clear homogeneous solution. Then the temperature of the mixture was lowered from this initial temperature of 25°C to a final temperature of -20°C. The formation of a solid product (called cake) was observed. The cake containing the crystallized paraffins was separated by filtration, washed with acetone, then dried and analyzed. The paraffins contained in the cake were extracted by dissolution in n-heptane heated to 90°C and then evaporation of the n-heptane under nitrogen flow.

[0096] The dewaxed oil (called filtrate) separated from the cake is recovered. The acetone contained in the filtrate was evaporated using a rotary evaporator at 70°C under vacuum at a rotation speed of 60 rpm, then the vacuum is broken to send a stream of nitrogen into the flask in order to have a total evaporation of the acetone.

[0097] The compositions of the extracted paraffins and the filtrate were analyzed as described with reference to Example 2. The results are summarized in Table 4. The heteroatom contents of the ex HPP diesel, the extracted paraffins and the filtrate are summarized in Table 5.

[0098] Table 4

[0099] Table 5

[0100] The ex-HPP diesel cut, extracted paraffins and dewaxed oil were analyzed by GC-MS under the following conditions:

[0101] Sample preparation:

[0102] • All samples were diluted in CS2 and analyzed by GCMS under the same conditions.

[0103] • Approximately 0.1 g of product in 6 g of CS2 Analytical conditions:

[0104] Injection on a GC-MS (GC-QTOF from Agilent) under the same conditions (slow programming to spread the detected molecules):

[0105] Split Mode Injector: 250°C - split ratio 100 - injected volume 1 pL

[0106] Column flow rate (He): 1 mL / min Oven: 35°C for 10 min, then 4°C / min up to 325°C for 10 min

[0107] Non-polar column: Thermo TG-5HT brand 30 m * 0.25 mm * 0.25 pm

[0108] Source Temperature: 200°C Quad Temperature: 150°C

[0109] 70eV electron impact source.

[0110] The GC-MS analysis spectra obtained are gathered in Figure 1. In the spectrum of ex-HPP diesel, if we take for example the nCis, the peak with high intensity is the paraffin, the neighboring peak with lower intensity is the corresponding linear olefin. In this example, the ex-HPP diesel cut contains linear paraffins and linear olefins in C10-C30. The extracted paraffins are mainly in nC15-nC30, with a small proportion of linear olefins. On the other hand, the filtrate contains mainly lighter fractions in C10-C19, with a higher proportion of olefins compared to the extracted paraffins.

[0111] Example 4: Hydrotreatment of the solid product of Example 1, 2 or 3

[0112] The solid from example 1, 2 or 3 can be hydrotreated according to the following procedure:

[0113] The solid may be introduced into an optional first hydrotreatment section (HDT1), primarily for hydrogenating diolefins, which is operated in the liquid phase. This step may comprise a plurality of reactors in series and / or parallel if guard reactors are used upstream or downstream of the first hydrogenation reactor. These guard reactors may be used to reduce the concentration of certain undesirable chemical species and / or elements such as chlorine, silicon and metals. Particularly undesirable metals include Si, Na, Ca, Mg, Fe and Hg.

[0114] A second hydrotreatment section (HDT2) is dedicated to olefin hydrogenation and demetallation (HDM), desulfurization (HDS), denitrogenation (HDN) and deoxygenation (HDO). HDT2 is operated in the gas phase. This section consists of one or more reactors operated in series, lead-lag or in parallel.

[0115] Since the hydrotreating reactions in sections HDT1 and HDT2 are exothermic, a cold hydrogen quench can be used to moderate the temperature increase and control the reaction.

[0116] Isolated, lead-lag, series and / or parallel guard reactors can be considered depending on the nature and quantity of the contaminant in the flow to be treated. In the event that the treatments of examples 1, 2 or 3 do not allow sufficient reduction of impurities to be obtained, guard reactors to remove chlorine and silicon can be operated in the gas phase. Silicon can also be trapped on the upper bed of a reactor in the HDT2 section or separately, upstream or downstream by the treatment of hot gases leaving the HDT2 section.

[0117] Chlorine and mercury can be separated by liquid or gas phase guard reactors.

[0118] There may be intermediate quenches between the beds or between the HDT1 and HDT2 reactors or no quenching. In the latter case, recycling of part of the flow leaving HDT1 or HDT2 must be carried out to control the temperature. Strict temperature control in HDT1 must be carried out when this step is implemented, in order to avoid clogging of the reactor and degradation of the catalytic hydrogenation conditions.

[0119] The operating pressure in each of the hydrotreatments HDT1 and HDT2 is 5-140 bars, preferably 20-30 bars for HDT1 and 20-140 bars, preferably 30-100 bars for HDT2, typically 30-40 bars for HDT2.

[0120] Typical temperature range at the inlet of HDT1 at the start of run (SOR): 150-200°C. The catalyst for HDT 1 usually comprises Pd (0.1-10% by weight) and / or Ni (0.1-60% by weight) and / or NiMo (0.1-60% by weight).

[0121] Typical HDT2 inlet temperature range at start of run (SOR): 200-340°C. Typical HDT2 outlet temperature range (SOR): 300-380°C, up to 450°C. The catalyst for HDT 2 usually comprises a NiMo (any type of commercial catalyst for refining or petrochemical applications), potentially a CoMo in the very last beds at the bottom of the reactor (any type of commercial catalyst for refining or petrochemical applications).

[0122] The HDT2 upper bed should preferably be operated with a NiMo having hydrogenating capacity as well as silicon trapping capacity. Such an upper bed can be considered as an adsorbent as well as a metal trap having also HDN activity and hydrogenating capacity. An example of an acceptable upper bed for this function includes commercially available NiMo catalyst adsorbents such as ACT971, ACT981 from Axens or equivalents from Haldor Topsoe, Axens, Criterion, etc. It is possible to have two separate beds in an HDT2 reactor, with quenching between the two beds or between the two reactors, if the two beds are in two separate reactors, or no quenching at all. Ideally, the intermediate quench is carried out using cold HDT2 effluent or by supplying cold hydrogen, i.e. at a temperature typically ranging from 15 to 30°C, in order to control the HDT2 exotherm.Dilution by recycle of the hydrocarbon stream to the HDT2 upper bed is not recommended due to the increased risk of bed fouling. The feedstock arriving at the HDT2 catalyst should be completely vaporized at all times, including in variable regime conditions such as during start-ups. Sending liquid hydrocarbons to the upper bed of an HDT2 reactor can generate fouling and an increase in the pressure difference between the inlet and outlet of the HDT2 reactor and lead to premature shutdown.

[0123] Depending on the metals possibly present in the solid to be hydrotreated, a hydrodemetallization catalyst, for example commercial, can be added to the upper bed of the HDT2 section in order to protect the lower catalytic beds from deactivation.

[0124] The effluent leaving the HDT2 section may comprise 97%m / m or 98%m / m or more of paraffins, not more than 2%m / m of olefins and may be used as such or fractionated according to distillation temperature ranges to obtain paraffins having a specific melting point meeting the specifications of a particular application, for example 70°C or more.

Claims

CLAIMS A process for producing paraffins by hydrotreating a composition comprising a plastic liquefaction oil, said composition comprising paraffins, olefins, aromatics and heteroatoms, the process comprising: (a) a step of separating a portion of the paraffins and olefins contained in said composition comprising at least one step of crystallizing (i) said composition by lowering the temperature from 10°C to 60°C from an initial temperature at which said composition is entirely liquid and obtaining a mixture comprising a solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms and an effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms, followed by at least one step of separating (ii) said solid product and said effluent, (b) a hydrotreating step of the solid product of step (a) in which the olefins contained in said solid product are hydrogenated and an effluent containing paraffins and at most 2 w / w olefins is produced. A process according to claim 1, characterized in that, during the separation step (a), said composition is mixed with at least one solvent prior to at least one crystallization step (i), the at least one solvent being in the liquid state and miscible with the composition at the temperatures at which step (a) is carried out. A process according to claim 2, further comprising a step of separating the at least one solvent from the effluent from the separation step (iii) and returning the separated at least one solvent to step (i). A process according to claim 2 or 3, characterized in that the at least one solvent is an organic solvent.A process according to claim 4, characterized in that the organic solvent is selected from an aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone, an alcohol, or mixtures thereof. A process according to claim 5, characterized in that the organic solvent is selected from a ketone and an alcohol.

7. A process according to any one of claims 2 to 6, characterized in that the volume ratio of said composition to solvent is 10 / 90 v / v to 90 / 10 v / v, preferably 20 / 80 v / v to 80 / 20 v / v, more preferably 40 / 60 v / v to 60 / 40 v / v or 45 / 55 v / v to 55 / 45 v / v.

8. A method according to any one of claims 1 to 7, characterized in that: the separation step (a) comprises: (i-1) a first crystallization step by lowering the temperature of said composition from 10°C to 60°C from a first initial temperature at which said composition is entirely liquid and obtaining a first mixture comprising a first solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms, and a first effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms, (ii-1) a first step of separating said first solid product and said first effluent, (i-2) a second crystallization step by lowering the temperature of said first effluent from 10°C to 60°C from a second initial temperature at which said first effluent is entirely liquid and obtaining a second mixture comprising a second solid product enriched in paraffins and depleted in olefins, aromatics and heteroatoms, and a second effluent depleted in paraffins and enriched in olefins, aromatics and heteroatoms, (ii-2) a second step of separating said second solid product and said second effluent, and the first solid product and the second solid product are subjected to step (b) of hydrotreatment.

9. A method according to any one of claims 1 to 8, characterized in that the separation step (ii), (ii-1) or (ii-2) is carried out by at least one step selected from filtration, decantation, centrifugation.

10. A process according to any one of claims 1 to 9, characterized in that the hydrotreating of step (b) is carried out in a single step in which the solid product(s) from step (a) are hydrogenated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence hydrogen at an absolute pressure of 20 to 140 bars, preferably 30 to 100 bars and in the presence of a hydrotreating catalyst. A process according to any one of claims 1 to 9, characterized in that the hydrotreating of step (b) is carried out in a first step (b-1) in which the solid product(s) from step (a) are hydrogenated at a temperature of 80 to 250°C, preferably 130 to 190°C in the presence of hydrogen at an absolute pressure of 5 to 60 bar, preferably 20 to 30 bar and in the presence of a first hydrotreating catalyst, and in a second step (b-2) in which the effluent from step (b-1) is hydrogenated at a temperature of 200 to 450°C, preferably 200 to 340°C in the presence of hydrogen at an absolute pressure of 20 to 140 bar, preferably 30 to 100 bar and in the presence of a second hydrotreating catalyst. Plastic waste recovery process comprising the following steps: (A) a step of liquefying waste containing plastics and obtaining a hydrocarbon product comprising a gaseous phase, a liquid phase and a solid phase, (B) a step of separating the liquid phase of said product, said liquid phase forming a plastic liquefaction oil, (C) a step of treating at least a part of the liquid phase by a process for producing paraffins according to any one of claims 1 to 11.

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