Method for treating plastic pyrolysis oil, comprising a hydrogenation step

Abstract

The present invention relates to a method for treating plastic pyrolysis oil, the method comprising the steps of: (a) selectively hydrogenating said feedstock in the presence of at least hydrogen and at least one hydrogenation catalyst at an average temperature of 140-340°C; the temperature on the outlet from step (a) is at least 15°C higher than the temperature on the inlet to step (a); obtaining a hydrogenated effluent; (b) hydrotreating said hydrogenated effluent in the presence of at least hydrogen and at least one hydrotreating catalyst; obtaining a hydrotreated effluent; the average temperature of step (b) is higher than the average temperature of step (a); (c) separating said hydrotreated effluent in the presence of an aqueous stream at a temperature of 50-370°C; obtaining at least one gaseous effluent, a liquid aqueous effluent and a liquid hydrocarbon effluent.

Description

[Technical field]

[0001] The present invention relates to a method for treating plastic pyrolysis oil to obtain a hydrocarbon-based effluent that can be directly incorporated into naphtha or diesel storage units or upgraded as a feedstock for steam cracking units. More particularly, the present invention relates to a method for treating a feedstock obtained from the pyrolysis of plastic waste to at least partially remove impurities that said feedstock may contain in relatively large amounts. [Background technology]

[0002] The plastics obtained from the collection and sorting channels may undergo a process of pyrolysis to obtain, in particular, pyrolysis oils. These plastic pyrolysis oils are generally combusted to generate electricity and / or used as fuel in industrial boilers or city heating.

[0003] Another route for upgrading plastic pyrolysis oils is the use of these plastic pyrolysis oils as feedstock for steam cracking units to (re)produce olefins, said olefins being the constituent monomers of certain polymers. However, plastic wastes are generally mixtures of several polymers, for example mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride and polystyrene. Furthermore, depending on the application, plastics may contain other compounds in addition to polymers, for example plasticizers, pigments, dyes or residues of polymerization catalysts. Plastic wastes may also contain small amounts of biomass, for example originating from household waste. The treatment of the wastes, especially storage, mechanical treatment, sorting, pyrolysis on the one hand, and also the storage and transport of the pyrolysis oil on the other hand, can also cause corrosion. As a result, the oil obtained from the pyrolysis of plastic waste contains many impurities, especially diolefins, metals, especially iron, silicon, or halogenated compounds, especially chlorine-based compounds, heteroelements, such as sulfur, oxygen and nitrogen, and insoluble materials, often in high and incompatible contents with the steam cracking unit or units downstream of the steam cracking unit, especially polymerization and selective hydrogenation processes. These impurities can cause problems of operability, especially corrosion, coking or catalyst deactivation, or incompatibility in the application of the target polymer. The presence of diolefins can also lead to problems of instability of the pyrolysis oil, which is characterized by the formation of gums. The gums and insoluble materials that may be present in the pyrolysis oil can cause clogging problems in this process.

[0004] Furthermore, during the steam cracking process, the yield of light olefins desired for petrochemistry, especially ethylene and propylene, is highly dependent on the quality of the feedstock sent for steam cracking. The Bureau of Mines Correlation Index (BMCI) is often used to characterize the hydrocarbon fractions. This index was developed for hydrocarbon-based products obtained from crude oil and is calculated from measurements of density and average boiling point: it is equal to 0 for linear paraffins and 100 for benzene. Its value is therefore higher if all the analyzed products have aromatic condensation structures, naphthenes having an intermediate BMCI between paraffins and aromatics. Overall, a higher yield of light olefins is obtained with a higher paraffin content and therefore a lower BMCI. Conversely, a higher yield of unwanted heavy compounds and / or coke is obtained with a higher BMCI.

[0005] In patent application WO 2005 / 023631 A an overall method for recycling plastic waste is proposed, which is very general and relatively complex, starting from the very step of pyrolysis of the plastic waste to a steam cracking step. The method of patent application WO 2005 / 023631 A comprises, inter alia, a step of hydrotreating the liquid phase obtained directly from the pyrolysis, preferably under very severe conditions, in particular with respect to temperature, for example at a temperature between 260 and 300° C., a step of separation of the hydrotreating effluent, and then a step of hydrodealkylation of the heavy effluents taken off in the separation, preferably at high temperatures, for example between 260 and 400° C.

[0006] Unpublished patent application FR20 / 01758 describes a method for treating plastic pyrolysis oil, which comprises the following steps: a) selective hydrogenation of olefins contained in said feedstock in the presence of hydrogen and a selective hydrogenation catalyst; obtaining a hydrogenated effluent; b) hydrotreating said hydrogenated effluent in the presence of hydrogen and a hydrotreating catalyst; obtaining a hydrotreated effluent; c) separation of the hydroprocessing effluent in the presence of an aqueous stream at a temperature between 50 and 370°C to obtain a gaseous effluent, an aqueous liquid effluent and a hydrocarbon-based liquid effluent; d) optionally a step of fractionation of all or part of the hydrocarbon-based effluent obtained from step c) to obtain a gas stream and at least two hydrocarbon-based streams, which may be a naphtha fraction and a heavier fraction; e) a recycle step comprising a portion of the hydrocarbon-based effluent obtained from separation step c) or a portion of the hydrocarbon-based stream obtained from fractionation step d) and / or at least one of the recovery phases to the selective hydrogenation step a) and / or to the hydrotreating step b).

[0007] According to application FR20 / 01.758, the selective hydrogenation step a) and the hydrotreating step b) are separate steps and are carried out in different reactors under different conditions. Moreover, according to application FR20 / 01.758, the selective hydrogenation step a) is carried out under mild conditions, in particular at temperatures between 100 and 250° C., which may lead to premature deactivation of the catalyst. Finally, according to application FR20 / 01.758, the hydrotreating step b) is generally carried out at significantly higher temperatures than the selective hydrogenation step a), in particular at temperatures between 250 and 430° C., requiring a device for heating between these two steps.

[0008] It would therefore be advantageous to carry out part of the diolefin hydrogenation reaction and part of the hydrotreating reaction, particularly the olefin hydrogenation reaction and part of the hydrodemetallation reaction, especially the silicon retention, in one and the same step at a temperature sufficient to limit catalyst deactivation.

[0009] This same process also makes it possible to benefit from the heat from the hydrogenation reactions, in particular the hydrogenation of some of the diolefins, and to have an increasing temperature profile in this process, thus making it possible to eliminate the need for a heating device between the catalytic section for hydrogenation and the catalytic section for hydrotreating. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2018 / 055555 Summary of the Invention [Means for solving the problem]

[0011] (Summary of the invention) The present invention relates to a method for processing a feedstock containing plastic pyrolysis oil, the method comprising the steps of: a) Hydrogenation step; carried out in a hydrogenation reaction section, using at least one fixed bed reactor, the fixed bed reactor containing n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrogenation catalyst, the hydrogenation reaction section being fed with at least the feedstock and a gas stream containing hydrogen, the average temperature during use of the hydrogenation reaction section being 140-400°C, the partial pressure of hydrogen being 1.0-10.0 MPa (absolute), and the hourly space velocity being 0.1-10.0 h -1 and the outlet temperature of the reaction section of step a) is at least 15° C. higher than the inlet temperature of the reaction section of step a); obtaining a hydrogenated effluent. b) a hydrotreating step, carried out in a hydrotreating reaction section, using at least one fixed bed reactor, containing n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the hydrogenated effluent from step a) and a gas stream containing hydrogen, said hydrotreating reaction section being used at an average temperature of 250-430° C., a partial pressure of hydrogen of 1.0-10.0 MPa (absolute), and an hourly space velocity of 0.1-10.0 h -1 and the average temperature of the reaction section of step b) is higher than the average temperature of the hydrotreating reaction section of step a); obtaining a hydrotreated effluent. b') an optional hydrocracking step, carried out in a hydrocracking reaction section using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, said hydrocracking reaction section being fed at least with the hydrotreated effluent from step b) and / or the fraction from step d) containing compounds with a boiling point above 175°C, and a gas stream containing hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute), and the hourly space velocity being between 0.1 and 10.0 h -1 obtaining a hydrocracked effluent which is sent to a separation step c); c) a separation step, feeding the hydrotreated effluent from step b) or the hydrocracked effluent from step b') and an aqueous solution, said steps being carried out at a temperature between 50 and 370°C, obtaining at least one gaseous effluent, an aqueous effluent and a hydrocarbon-based effluent, d) optionally fractionating all or part of the hydrocarbon-based effluent obtained from step c); obtaining at least one gaseous effluent, at least one fraction comprising compounds having a boiling point less than or equal to 175° C., and at least one hydrocarbon-based fraction comprising compounds having a boiling point greater than 175° C.

[0012] One advantage of the process according to the invention is that the oil obtained from the pyrolysis of plastic waste is purified from at least a part of its impurities, which makes it possible to hydrogenate it and therefore upgrade it, in particular by incorporating it directly in a fuel storage unit or else adapting it to a treatment in a steam cracking unit in order to be able to obtain in particular improved yields of light olefins, which may also serve as monomers in the manufacture of polymers.

[0013] Another advantage of the present invention is that it prevents the risk of clogging and / or corrosion of the processing units in which the inventive process is carried out, a risk that is exacerbated by the often large amounts of diolefins, metals and halogenated compounds present in plastic pyrolysis oils.

[0014] The process of the invention therefore makes it possible to obtain a hydrocarbon-based effluent obtained from plastic pyrolysis oil at least partially free of the impurities of the starting plastic pyrolysis oil, thus limiting the operational problems that these impurities may cause, such as corrosion, coking or catalyst deactivation problems, in particular in the steam cracking unit and / or in the units located downstream of the steam cracking unit, especially in the polymerization and hydrogenation units. The removal of at least a portion of the impurities from the oil obtained from the pyrolysis of plastic waste also makes it possible to expand the applications of the target polymers, reducing their incompatibility with the applications.

[0015] According to one variant, the method comprises a step d).

[0016] According to one variant, the method comprises a step b').

[0017] According to one variant, the amount of hydrogen-containing gas stream fed to the reaction section of step a) is such that the hydrogen coverage is equal to the volume of the feedstock (m 3 ) Hydrogen 50~1000Nm 3 (Nm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 200-300Nm 3 (Nm 3 / m 3 ) is set to be.

[0018] According to one variant, the outlet temperature of step a) is at least 30° C. higher than the inlet temperature of step a).

[0019] According to one variant, at least a portion of the hydrocarbon-based effluent obtained from the separation step c) or at least a portion of the naphtha cut comprising compounds with a boiling point below 175° C. obtained from the fractionation step d) is sent to a hydrogenation step a) and / or a hydrotreating step b).

[0020] According to one variant, at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from fractionation step d) is sent to a hydrogenation step a) and / or a hydrotreating step b) and / or a hydrocracking step b').

[0021] According to one variant, the method comprises a step a0) of pretreating the feedstock comprising plastic pyrolysis oil, said pretreatment step being carried out upstream of the hydrogenation step a) and comprising a filtration step and / or an electrostatic separation step and / or a washing step with an aqueous solution and / or an adsorption step.

[0022] According to one variant, the hydrocarbon-based effluent obtained from the separation step c) or at least one of the two liquid hydrocarbon-based streams obtained from step d) is sent, in whole or in part, to a steam cracking step e), which is carried out in at least one pyrolysis furnace at a temperature of 700-900° C. and a pressure of 0.05-0.3 MPa (relative).

[0023] According to one variant, the reaction section of step a) employs at least two reactors operating in a sequence-variable mode.

[0024] According to one variant, a stream containing the amine is injected upstream of step a).

[0025] According to one variant, the hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group comprising either at least one group VIII element and at least one group VIB element, or at least one group VIII element.

[0026] According to one variant, the hydrotreating catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group comprising at least one group VIII element and / or at least one group VIB element.

[0027] According to one variant, the process also comprises a second hydrocracking step b''), which is carried out in a hydrocracking reaction section using at least one fixed bed, which comprises n catalyst beds, n being an integer equal to or greater than 1, each of which comprises at least one hydrocracking catalyst, said hydrocracking reaction section being fed with the fraction from step d) comprising compounds having a boiling point above 175°C and a gas stream comprising hydrogen, the temperature at which the hydrocracking reaction section is used being between 250 and 450°C, the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute) and the hourly space velocity being between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to the separation step c).

[0028] According to one variant, the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminum, amorphous silica-alumina and zeolites, and a hydrodehydrogenation functional group comprising at least one Group VIB metal selected, alone or in mixtures, from chromium, molybdenum and tungsten, and / or at least one Group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0029] The present invention also relates to a product which may be obtained, preferably is obtained, via the process according to the invention.

[0030] According to this variant, the product comprises, relative to the total weight of the product: - Total content of metallic elements: not more than 5.0 ppm by weight; - Iron content: 100 ppb or less by weight; - Silicon content: 1.0 ppm by weight or less; - Sulfur content: less than 500 ppm by weight, - Nitrogen content: less than 100 ppm by weight, - Chlorine content: 10 ppm by weight or less.

[0031] According to the invention, pressures are absolute pressures, also written abs., and are given in MPa (absolute) (or MPa abs.), unless otherwise stated.

[0032] According to the present invention, the expressions "comprised between ... and ..." and "between A and B or A to B (between ... and ...)" are equivalent and mean that both limits of the interval are included in the stated range of values. If this is not the case and if the limit is not included in the stated range, a clarification therefor is provided by the present invention.

[0033] For purposes of the present invention, the various ranges of parameters for a given process, such as pressure ranges and temperature ranges, may be used alone or in combination, e.g., for purposes of the present invention, a range of preferred pressure values ​​may be combined with a range of more preferred temperature values.

[0034] In the following specification, specific and / or preferred embodiments of the present invention may be described, which may be implemented separately or in combination together, without any limitation thereto, where the combination is technically feasible.

[0035] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to metals from columns 8, 9 and 10 according to the new IUPAC classification.

[0036] The metal content is measured by X-ray fluorescence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] (Detailed Description) (Feed material) According to the invention, "plastic pyrolysis oil" is an oil obtained from the pyrolysis of plastics, preferably plastic waste, especially plastic waste arising from collection and sorting channels, advantageously in liquid form at room temperature. It can also be obtained from the pyrolysis of worn tires.

[0038] It especially comprises a mixture of hydrocarbon-based compounds, in particular paraffins, mono- and / or diolefins, naphthenes and aromatic compounds, with a minimum of 80% by weight of these hydrocarbon-based compounds preferably having a boiling point below 700° C., preferably below 550° C. In particular, depending on the origin of the pyrolysis oil, said oil comprises up to 70% by weight of paraffins, up to 90% by weight of olefins and up to 90% by weight of aromatic compounds, the sum of paraffins, olefins and aromatic compounds being understood to amount to 100% by weight of hydrocarbon-based compounds.

[0039] The density of pyrolysis oil is generally between 0.75 and 0.99 g / cm, measured at 15 °C according to ASTM D4052 method. 3 , preferably 0.75 to 0.95 g / cm 3 It is.

[0040] Plastic pyrolysis oil can further contain, and usually does contain, impurities, such as metals, especially iron, silicon, or halogenated compounds, especially chlorinated compounds. These impurities may be present in high contents in plastic pyrolysis oil, for example, up to 350 ppm by weight, even 700 ppm by weight, or even up to 1000 ppm by weight of halogen elements (especially chlorine) provided by halogenated compounds, and up to 100 ppm by weight, or even up to 200 ppm by weight of metal or metalloid elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals and metalloids may be likened to contaminants of metallic nature and are called metals or metallic or metalloid elements. In particular, metals or metallic or metalloid elements that may be contained in oil obtained from the pyrolysis of plastic waste include silicon, iron or both of these elements. The plastic pyrolysis oil may also contain other impurities, such as heteroelements, provided inter alia by sulfur, oxygen and / or nitrogen compounds, the content of which is generally less than 10,000 ppm by weight of heteroelements, preferably less than 4,000 ppm by weight of heteroelements.

[0041] The feedstock for the process according to the invention comprises at least one plastic pyrolysis oil. The feedstock may consist exclusively of plastic pyrolysis oil(s). Preferably, the feedstock comprises at least 50% by weight, preferably 70% to 100% by weight of plastic pyrolysis oil, i.e. preferably 50% to 100% by weight, preferably 70% to 100% by weight of plastic pyrolysis oil, relative to the total weight of the feedstock.

[0042] The feedstock for the process according to the invention may include, in addition to the plastic pyrolysis oil(s), traditional petroleum-based feedstocks, or feedstocks obtained from the conversion of biomass, which are co-processed with the feedstock plastic pyrolysis oil.

[0043] The conventional petroleum-based feedstock may advantageously be a fraction or mixture of fractions of the naphtha, gas oil or gas oil under vacuum type.

[0044] The feedstock obtained from the conversion of biomass can advantageously be chosen from vegetable oils, oils from algae, i.e. algal oils, fish oils, used food oils, and fats of vegetable or animal origin, or mixtures of such feedstocks. The vegetable oils are advantageously derived from plants, totally or partially unrefined or refined, chosen from rapeseed, sunflower, soybean, palm, olive, coconut, coconut kernel, castor oil plant, cotton, peanut oil, linseed oil and sea kale oil, and all oils derived, for example, from sunflower or rapeseed by genetic modification or hybridization, this list being non-limiting. The animal fats are advantageously chosen from blubber and fats consisting of residues from the food industry, or fats obtained from the catering industry. Frying oils, various animal oils, for example fish oil, tallow or lard, can also be used.

[0045] The feedstock obtained from the conversion of biomass can be selected from feedstock originating from thermal or catalytic conversion processes of biomass, for example from biomass, in particular from lignocellulosic biomass, but also from oils resulting from liquefaction processes, for example hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, including plants, animals and their by-products. The term "lignocellulosic biomass" refers to biomass derived from plants and their by-products. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and aromatic polymers (lignin).

[0046] The feedstock obtained from the conversion of biomass may advantageously also be chosen from feedstocks obtained from the paper industry.

[0047] Plastic pyrolysis oil may be obtained from thermal, catalytic pyrolysis processes or alternatively may be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0048] (Preprocessing (optional)) Said feedstock comprising plastic pyrolysis oil may advantageously be pretreated in an optional pretreatment step a0) before the hydrogenation step a) to obtain a pretreated feedstock, which is fed to step a).

[0049] This optional pretreatment step a0) makes it possible to reduce the amount of contaminants, in particular the amount of iron and / or silicon and / or chlorine, that may be present in the feedstock containing plastic pyrolysis oil.The optional pretreatment step a0) of the feedstock containing plastic pyrolysis oil is therefore advantageously carried out in particular when the feedstock contains more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of metal elements, in particular when the feedstock contains more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, even more particularly more than 20 ppm by weight of silicon.Similarly, the optional pretreatment step a0) of the feedstock containing plastic pyrolysis oil is advantageously carried out in particular when the feedstock contains more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight of chlorine.

[0050] Said optional pretreatment step a0) may be carried out via any method known to the person skilled in the art for reducing the amount of contaminants, which may include, inter alia, a filtration step and / or an electrostatic separation step and / or a washing step with an aqueous solution and / or an adsorption step.

[0051] The optional pretreatment step a0) is advantageously carried out at a temperature of 0 to 150° C., preferably 5 to 100° C., and at a pressure of 0.15 to 10.0 MPa (absolute), preferably 0.2 to 1.0 MPa (absolute).

[0052] According to one variant, said optional pretreatment step a0) is carried out in an adsorption section operated in the presence of at least one adsorbent. The adsorbent is preferably of the alumina type and has a concentration of 100 ml 2 / g or more, preferably 200m 2 The specific surface area of ​​the at least one adsorbent is advantageously greater than 600 m 2 / g or less, especially 400m 2 The specific surface area of ​​the adsorbent is the surface area measured by the BET method, i.e. the specific surface area determined by nitrogen adsorption according to standard ASTM D 3663-78, established from the Brunauer-Emmett-Teller method described in the periodical The Journal of the American Chemical Society, 60, 309 (1938).

[0053] Advantageously, said adsorbent contains less than 1% by weight of metallic elements, preferably no metallic elements. The term "metallic elements of the adsorbent" should be understood to refer to elements from groups 6 to 10 of the Periodic Table of the Elements (new IUPAC classification). The residence time of the feedstock in the adsorbent section is generally between 1 and 180 minutes.

[0054] The adsorption section of optional step a0) comprises at least one adsorption column, preferably at least two adsorption columns, preferentially 2 to 4 adsorption columns, which contain the adsorbent. When the adsorption section comprises two adsorption columns, one mode of operation may be what is called according to the technical term "swing" operation, where one of the columns is online, i.e. in service, while the other column is in reserve. When the adsorbent of the online column becomes worn out, this column is isolated, while the in-reserve column is placed online, i.e. in service. The used adsorbent may then be regenerated in situ and / or replaced with fresh adsorbent, and the column containing it may be placed online again, where the other column is isolated.

[0055] Another mode of operation is to have at least two columns operated in series. When the adsorbent of the column placed at the top is worn out, this first column is isolated and the used adsorbent is either regenerated in situ or replaced with fresh adsorbent. The column is then brought back online at the last position and so on. This mode of operation is known as permutable mode or PRS (permutable reactor system) or also the specialized term "lead and lag". The combination of at least two adsorption columns makes it possible to overcome the possible and potentially rapid poisoning and / or clogging of the adsorbent by the combined action of metal contaminants, diolefins, gums derived from diolefins and insolubles that may be present in the plastic pyrolysis oil to be treated. The reason for this is that the presence of at least two adsorption columns allows easy replacement and / or regeneration of the adsorbent, advantageously without shutting down the pretreatment unit and even the process, thus reducing the risk of clogging and therefore making it possible to avoid shutting down the unit due to clogging, controlling costs and limiting adsorbent consumption.

[0056] According to another variant, said optional pretreatment step a0) is carried out in a section for washing with an aqueous solution, for example water or an acidic or basic solution. This washing section can comprise a device for contacting the feedstock with an aqueous solution and a device for phase separation so as to obtain, on the one hand, a pretreated feedstock and, on the other hand, an aqueous solution containing impurities. Among these devices, for example, stirred reactors, decanters, mixer-decanters and / or cocurrent or countercurrent washing columns may be mentioned.

[0057] Said optional pretreatment step a0) may optionally be fed with a recycle stream, advantageously at least a part of the recycle stream obtained from step h) of the present process, either in a mixture with the feedstock comprising plastic pyrolysis oil or separately thereto.

[0058] Said optional pretreatment step a0) therefore makes it possible to obtain a pretreated feedstock which is then fed to the hydrogenation step a).

[0059] (Hydrogenation step a) According to the invention, the process comprises a hydrogenation step a), which is carried out in a hydrogenation reaction section, using at least one fixed bed reactor, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrogenation catalyst, said hydrogenation reaction section being fed at least with said feedstock and a gas stream comprising hydrogen, said hydrogenation reaction section being used at an average temperature between 140 and 400° C., a partial pressure of hydrogen between 1.0 and 10.0 MPa (absolute) and an hourly space velocity between 0.1 and 10.0 h -1 and the outlet temperature of the reaction section of step a) is at least 15° C. higher than the inlet temperature of the reaction section of step a) to obtain a hydrogenated effluent.

[0060] Step a) is carried out under conditions of hydrogen pressure and pressure that allow, inter alia, the hydrogenation of diolefins and olefins at the beginning of the hydrogenation reaction section while at the same time allowing an increasing temperature profile such that the outlet temperature of the reaction section of step a) is at least 15° C. higher than the inlet temperature of the reaction section of step a). In fact, the amount of hydrogen required to allow at least partial hydrogenation of the diolefins and olefins present in the plastic pyrolysis oil, at least partial hydrodemetallization of metals, inter alia the retention of silicon, and also at least partial conversion of chlorine (to HCl) is injected. The hydrogenation of diolefins and olefins therefore makes it possible to avoid or at least limit the formation of “gums”, i.e. the polymerization of diolefins and olefins, and therefore the formation of oligomers and polymers, which can clog the reaction section of the hydrotreating step b). In parallel with the hydrogenation, the hydrodemetallization, inter alia the retention of silicon during step a), makes it possible to limit the deactivation of the catalyst in the hydrotreating reaction section of step b). Furthermore, the conditions of step a), in particular the temperature and its increase profile, make it possible to convert at least a portion of the chlorine.

[0061] The control of temperature is therefore important in this step and must satisfy competing constraints. On the one hand, the temperature at the inlet of the hydrogenation reaction section and throughout the hydrogenation reaction section must be sufficiently low to allow the hydrogenation of diolefins and olefins at the start of the hydrogenation reaction section. On the other hand, the inlet temperature of the hydrogenation reaction section must be sufficiently high to avoid catalyst deactivation. Since the hydrogenation reactions, in particular the hydrogenation reactions of some of the olefins and diolefins, are highly exothermic, an increasing temperature profile is therefore observed in the hydrogenation reaction section. This higher temperature at the end of said section makes it possible to carry out the reactions of hydrodemetallation and hydrodechlorination. The outlet temperature of the reaction section of step a) is therefore at least 15° C., preferably at least 25° C., particularly preferably at least 30° C. higher than the inlet temperature of the reaction section of step a).

[0062] The temperature difference between the inlet and the outlet of the reaction section of step a) is adapted for the optional injection of any gas (hydrogen) or liquid quench stream (e.g. recycle of the streams resulting from steps c) and / or d)).

[0063] The temperature difference between the inlet and the outlet of the reaction section of step a) is due exclusively to the exothermic nature of the chemical reaction taking place in the reaction section and can therefore be accommodated without the use of heating means (oven, heat exchanger, etc.).

[0064] The inlet temperature of the reaction section in step a) is 135 to 385°C, preferably 210 to 335°C.

[0065] The outlet temperature of the reaction section in step a) is 150-400°C, preferably 225-350°C.

[0066] According to the invention, it is advantageous to carry out the hydrogenation reaction of diolefins and part of the hydrotreating reaction in one and the same step, at a temperature sufficient to limit the deactivation of the catalyst of step a), which is manifested by a drop in the diolefin conversion. This same step also makes it possible to benefit from the heat from the hydrogenation reaction, in particular the hydrogenation of part of the olefins and diolefins, and to increase the temperature profile in this step, thus eliminating the need for devices between the catalytic section for hydrogenation and the catalytic section for hydrotreating.

[0067] The reaction section advantageously carries out hydrogenation in the presence of at least one hydrogenation catalyst, with an average temperature (or WABT as defined below) of 140-400°C, preferably 220-350°C, particularly preferably 260-330°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute), preferably 1.5-8.0 MPa (absolute), and an hourly space velocity (HSV) of 0.1-10.0 h -1 , preferably 0.2 to 5.0 h -1 , highly preferably 0.3~3.0h -1 It is.

[0068] According to the invention, the weight-average bed temperature (WABT) of the reaction section corresponds to a terminology well known to the skilled person. The average temperature is advantageously determined depending on the catalyst system used, the device and its configuration. The average temperature (i.e. WABT) is calculated in the following way:

[0069]

number

[0070] In the formula, T inlet : temperature of the effluent at the inlet of the reaction section, T outlet : The temperature of the effluent at the outlet of the reaction section.

[0071] Hourly space velocity (HSV) is defined herein as the ratio of the hourly volumetric flow rate of the feedstock containing plastic pyrolysis oil (optionally pretreated) to the volume of the catalyst(s).

[0072] The hydrogen coverage is defined as the ratio at 15°C of the hydrogen volumetric flow rate taken under standard temperature and pressure conditions relative to the volumetric flow rate of the "fresh" feedstock, i.e. the feedstock to be treated (possibly pretreated, without taking into account any recycled fractions) (per volume of feedstock (m 3 ) per m of H2 standard 3 (Nm 3 )).

[0073] The amount of gas stream containing hydrogen (H2) fed to said reaction section of step a) is advantageously determined so that the hydrogen coverage is equal to or greater than the volume (m 3 ) Hydrogen 50~1000Nm 3 (Nm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 50-500Nm 3 (Nm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 200-300Nm 3 (Nm 3 / m 3 In fact, the amount of hydrogen required to enable at least partial hydrogenation of diolefins and olefins and at least partial dehydrogenation of metals, in particular retention of silicon, and also at least partial conversion of chlorine (to HCl) is greater than the amount of hydrogen required to enable only the hydrogenation of diolefins as described in FR 20 / 01.758.

[0074] The hydrogenation reaction section of step a) is fed at least with said feedstock comprising plastic pyrolysis oil or with a pretreated feedstock obtained from the optional pretreatment step a0) and with a gas stream comprising hydrogen (H2). Optionally, said reaction section of step a) may also be fed with at least a portion of a recycle stream advantageously obtained from step c) or step d).

[0075] Advantageously, the reaction section of step a) comprises from 1 to 5 reactors, preferably from 2 to 5 reactors, particularly preferably it comprises 2 reactors. The advantage of a hydrogenation reaction section comprising several reactors consists in an optimized treatment of the feedstock while at the same time reducing the risk of clogging of the catalyst bed(s) and therefore making it possible to avoid unit shutdowns due to clogging.

[0076] According to one variant, these reactors are operated in permutable mode, also known as PRS (Permutable Reactor System) or otherwise as "Lead and Drag". The combination of at least two reactors in PRS mode makes it possible to isolate one reactor, drain the spent catalyst, recharge the reactor with fresh catalyst and return said reactor to service without stopping the process. The PRS technology is described in particular in patent FR2681871.

[0077] According to one particularly preferred variant, the hydrogenation reaction section of step a) comprises two reactors operated in a sequence-variable mode.

[0078] Advantageously, reactor inserts, for example of the filter plate type, may be used to prevent clogging of the reactor(s). Examples of filter plates are described in patent FR3051375.

[0079] Advantageously, said hydrogenation catalyst comprises a support, preferably a mineral support, and a hydrodehydrogenation functional group.

[0080] According to one variant, the hydrodehydrogenation functional group comprises in particular at least one group VIII element and at least one group VIB element, the group VIII element being preferably selected from nickel and cobalt and the group VIB element being preferably selected from molybdenum and tungsten. According to this variant, the total content, expressed as oxides, of metallic elements from groups VIB and VIII is preferably between 1% and 40% by weight, preferentially between 5% and 30% by weight, relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO, respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3 and WO3, respectively.

[0081] The weight ratio of the Group VIB metal(s) relative to the Group VIII metal(s), expressed as metal oxide, is preferably 1-20, preferably 2-10.

[0082] According to this variant, the reaction section of step a) comprises, for example, a hydrogenation catalyst comprising 0.5% to 12% by weight of nickel, preferably 1% to 10% by weight of nickel (expressed as nickel oxide NiO relative to the weight of the catalyst), and 1% to 30% by weight of molybdenum, preferably 3% to 20% by weight of molybdenum (expressed as molybdenum oxide MoO3 relative to the weight of the catalyst), on a support, preferably a mineral support, preferably an alumina support.

[0083] According to another variant, the hydrodehydrogenation functional group comprises, and preferably consists of, at least one group VIII element, preferably nickel. According to this variant, the content of nickel oxide is preferably between 1% and 50% by weight, preferably between 10% and 30% by weight, relative to the weight of said catalyst. This type of catalyst is preferably used in its reduced form on a support, preferably on a mineral support, preferably on an alumina support.

[0084] The support for the hydrogenation catalyst is preferably selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may contain a dopant compound, in particular an oxide selected from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and mixtures of these oxides. Preferably, the hydrogenation catalyst comprises an alumina support, optionally doped with phosphorus and optionally with boron. If phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina. If boron trioxide B2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina. The alumina used may be, for example, γ (gamma) or η (eta) alumina.

[0085] The hydrogenation catalyst is, for example, in the form of extrudates.

[0086] Highly preferably, step a) may use, in addition to the hydrogenation catalyst(s) described above, at least one hydrogenation catalyst used in step a) containing less than 1% by weight nickel and at least 0.1% by weight nickel, preferably 0.5% by weight nickel, expressed as nickel oxide NiO relative to the weight of the catalyst, and less than 5% by weight molybdenum, expressed as molybdenum oxide MoO3 relative to the weight of the catalyst, and at least 0.1% by weight molybdenum, preferably 0.5% by weight molybdenum, on an alumina support. This catalyst is not highly metal loaded and may preferably be placed upstream or downstream of the hydrogenation catalyst(s).

[0087] Said hydrogenation step a) makes it possible to obtain a hydrogenated effluent, i.e. an effluent with a reduced content of olefins, especially diolefins, and metals, especially silicon. The content of impurities, especially diolefins, of the hydrogenated effluent obtained at the end of step a) is reduced relative to the content of the same impurities, especially diolefins, contained in the feedstock for the process. Hydrogenation step a) generally makes it possible to convert at least 40%, preferably at least 60%, of the diolefins contained in the initial feedstock, and also at least 40%, preferably at least 60%, of the olefins. Step a) also makes it possible to at least partially remove other contaminants, such as silicon and chlorine. Preferably, at least 50%, more preferably at least 75%, of the chlorine and silicon of the initial feedstock are removed during step a). The hydrogenated effluent obtained at the end of hydrogenation step a) is preferably sent directly to hydrotreating step b).

[0088] (Hydrotreatment step b)) According to the invention, the process comprises a hydrogenation step b), which is carried out in a hydrotreating reaction section, using at least one fixed bed reactor, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the hydrogenated effluent from step a) and with a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature between 250 and 430° C., with a partial pressure of hydrogen between 1.0 and 10.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 and the average temperature of the reaction section of step b) is higher than the average temperature of the hydrotreating reaction section of step a) to obtain a hydrotreated effluent.

[0089] Advantageously, step b) carries out hydrotreating reactions well known to those skilled in the art, more particularly hydrotreating reactions such as hydrogenation, hydrodesulfurization and hydrodenitrification of aromatic compounds, followed by hydrogenation and then hydrodemetallization of olefins and residual halogenated compounds.

[0090] The hydrotreating reaction section is advantageously carried out at a pressure equivalent to that used in the reaction section of the hydrogenation step a), but at an average temperature higher than the average temperature in the reaction section of the hydrogenation step a). The hydrotreating reaction section is therefore advantageously carried out at an average temperature of 250-430°C, preferably 280-380°C, with a hydrogen partial pressure of 1.0-10.0 MPa (absolute) and an hourly space velocity (HSV) of 0.1-10.0 h -1 , preferably 0.1 to 5.0 h -1 , preferentially 0.2~2.0h -1 , preferably 0.2 to 1 h -1 The hydrogen coverage in step b) is advantageously determined by the volume (m ) of fresh feedstock fed to step a). 3 ) Hydrogen 50~1000Nm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 50-500Nm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 100~300Nm 3 The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those given above.

[0091] The hydrotreating reaction section is advantageously fed with at least the hydrogenated effluent from step a) and a hydrogen-containing gas stream to a first catalyst bed of a first functioning reactor. Optionally, the reaction section of step b) may also be fed with a recycle stream, advantageously at least a part of a recycle stream obtained from step c) or from optional step d).

[0092] Advantageously, said step b) is carried out in a hydrotreating reaction section, which comprises at least one, preferably from 1 to 5, fixed bed reactors. The fixed bed reactors contain n catalyst beds, n being an integer greater than or equal to 1, preferably from 1 to 10, preferably from 2 to 5. Said bed(s) each contain at least one, and preferably not more than 10, hydrotreating catalysts. When the reactor comprises several catalyst beds, i.e. at least 2, preferably from 2 to 10, preferably from 2 to 5, said catalyst beds are preferably arranged in series in said reactor.

[0093] If step b) is carried out in a hydrotreating reaction section comprising several reactors, preferably two reactors, these reactors can be operated in series and / or in parallel and / or in variable sequence (or PRS) mode and / or in swing mode. The various optional operating modes, PRS (or lead and drag) mode and swing mode, are well known to the person skilled in the art and are advantageously defined above.

[0094] In another embodiment of the invention, the hydrotreating reaction section comprises a single fixed bed reactor containing n catalyst beds, where n is an integer equal to or greater than 1, preferably between 1 and 10, preferably between 2 and 5.

[0095] In one particularly preferred embodiment, the hydrogenation reaction section of step a) comprises two reactors operated in a sequencially variable mode, followed by the hydrotreating reaction section of step b), which comprises a single fixed bed reactor.

[0096] Advantageously, the hydrotreating catalyst used in step b) may be selected from known hydrodemetallization, hydrotreating or silicon trapping catalysts, which are particularly used for the treatment of petroleum fractions, and combinations thereof.Known hydrodemetallization catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 5221656, US 5827421, US 7119045, US 5622616 and US 5089463.Known hydrotreating catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 6589908, US 4818743 or US 6332976.Known silicon trapping catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0097] In particular, said hydrotreating catalyst comprises a support, preferably a mineral support, and at least one metallic element having hydrodehydrogenation function. Said metallic element having hydrodehydrogenation function advantageously comprises at least one group VIII element and / or at least one group VIB element, the group VIII element being preferably selected from the group consisting of nickel and cobalt, and the group VIB element being preferably selected from the group consisting of molybdenum and tungsten. The total content, expressed as oxides, of metallic elements from groups VIB and VIII is preferably between 0.1% and 40% by weight, preferentially between 5% and 35% by weight, relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO, respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3, WO3, respectively. The weight ratio, expressed as metal oxide, between the group VIB metal(s) relative to the group VIII metal(s) is preferably 1.0 to 20, preferably 2.0 to 10. For example, the hydrotreating reaction section of step b) of the method comprises a hydrotreating catalyst comprising 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO relative to the total weight of the hydrotreating catalyst, preferably 1% to 8% by weight of nickel, and 1.0% to 30% by weight of molybdenum, preferably 3.0% to 29% by weight of molybdenum, expressed as molybdenum oxide MoO3 relative to the total weight of the hydrotreating catalyst, on a mineral support, preferably an alumina support.

[0098] The support for the hydrotreating catalyst is advantageously selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may contain a dopant compound, in particular an oxide selected from boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and mixtures of these oxides. Preferably, the hydrotreating catalyst comprises an alumina support, preferably the alumina support is doped with phosphorus and optionally doped with boron. If phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina. If boron trioxide B2O5 is present, its concentration is less than 10% by weight relative to the weight of the alumina and advantageously at least 0.001% by weight relative to the total weight of the alumina. The alumina used may be, for example, γ (gamma) or η (eta) alumina.

[0099] The hydrotreating catalyst is, for example, in the form of extrudates.

[0100] Advantageously, the hydrotreating catalyst used in step b) of the process has a specific surface area of ​​250 m 2 / g or more, preferably 300m 2 The specific surface area of ​​the hydrotreating catalyst is advantageously 800 m 2 / g or less, preferably 600m 2 / g or less, especially 400m 2 / g or less. The specific surface area of ​​the hydrotreating catalyst is measured by the BET method, i.e., the specific surface area is determined by nitrogen adsorption according to the standard ASTM D 3663-78, established from the Brunauer-Emmett-Teller method described in the periodical The Journal of the American Chemical Society, 60, 309 (1938). Such a specific surface area allows for a further improvement in the removal of pollutants, in particular metals, such as silicon.

[0101] According to another aspect of the present invention, the hydrotreating catalyst also comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to by the term "additivated catalyst". In general, the organic compounds are compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide functional groups or else compounds containing a furan ring or else sugars.

[0102] Advantageously, the hydrotreating step b) allows hydrogenation of at least 80%, preferably all, of the olefins remaining after the hydrotreating step a), but also allows at least a partial conversion of other impurities present in the feedstock, such as aromatic compounds, metal compounds, sulfur compounds, nitrogen compounds, halogen compounds (especially chlorine compounds) and oxygen compounds.Preferably, the nitrogen content at the end of step b) is less than 10 ppm by weight.Step b) may also allow further reduction of the contaminant content, such as the metal content, in particular the silicon content.Preferably, the metal content at the end of step b) is less than 10 ppm by weight, preferably less than 2 ppm by weight, and the silicon content is less than 5 ppm by weight.

[0103] (Hydrocracking step (optional) b') According to one variant, the process of the invention may comprise a hydrocracking step b'), which is carried out on the hydrocarbon-based fraction comprising compounds with a boiling point above 175° C. (diesel fraction), either immediately after the hydrotreating step b) or after the fractionation step d).

[0104] Advantageously, step b') carries out a hydrocracking reaction well known to the person skilled in the art, more particularly making it possible to convert the heavy compounds contained in the hydrotreated effluent obtained from step b) or separated during the fractionation step d), such as compounds having a boiling point above 175° C., into compounds having a boiling point below 175° C. Other reactions may follow, such as hydrogenation of olefins or aromatics, hydrodemetallization, hydrodesulfurization, hydrodenitrification, etc.

[0105] Compounds with boiling points above 175°C have a high BMCI and contain more naphthenic, naphthenoaromatic and aromatic compounds relative to the lighter compounds, leading to higher C / H ratios. This high ratio causes coking in the steam cracker, necessitating a dedicated steam cracking furnace for this fraction. If it is desired to minimize the yield of these heavy compounds (diesel fraction) and maximize the yield of light compounds (naphtha fraction), these compounds can be at least partially converted to light compounds (the fraction generally preferred for steam cracking units) by hydrocracking.

[0106] The process of the invention may therefore comprise a hydrocracking step b'), which is carried out in a hydrocracking reaction section using at least one fixed bed comprising n catalyst beds, n being an integer equal to or greater than 1, each comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with said hydrotreated effluent from step b) and / or the fraction comprising compounds having a boiling point above 175°C from step d) and a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, with a partial pressure of hydrogen between 1.5 and 20.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to fractionation step d).

[0107] Therefore, the hydrocracking reaction section is advantageously carried out at an average temperature of 250 to 480° C., preferably 320 to 450° C., at a hydrogen partial pressure of 1.5 to 20.0 MPa (absolute), preferably 2 to 18.0 MPa (absolute), and at an hourly space velocity (HSV) of 0.1 to 10.0 h -1 , preferably 0.1 to 5.0 h -1 , preferentially 0.2~4h -1 The hydrogen coverage in step c) is advantageously determined by the volume (m ) of fresh feedstock fed to step a). 3 ) Hydrogen 80~2000Nm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 200~1800Nm 3 The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those given above.

[0108] Advantageously, said hydrocracking reaction section is carried out at a pressure which is equivalent to the pressure used in the reaction section of the hydrogenation step a) or of the hydrotreating step b).

[0109] Advantageously, said step b') is carried out in a hydrocracking reaction section, which comprises at least one, preferably between 1 and 5, fixed bed reactors. This fixed bed reactor contains n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, preferably between 2 and 5. Said bed(s) each comprises at least one and preferably not more than 10 hydrocracking catalysts. When the reactor comprises several catalyst beds, i.e. at least 2, preferably between 2 and 10, preferably between 2 and 5, said catalyst beds are preferably arranged in series in said reactor.

[0110] The hydrotreating step b) and the hydrocracking step b') may advantageously be carried out in the same or in different reactors, in which case the reactor comprises several catalyst beds, the first of which comprises the hydrotreating catalyst(s) and the following catalyst beds comprising the hydrocracking catalyst(s).

[0111] The hydrocracking step can be carried out in one step (step b')) or in two steps (steps b') and b''). When it is carried out in two steps, a separation of the effluent obtained from the first hydrocracking step b') is carried out, which makes it possible to obtain, during steps c) and d), a fraction comprising compounds with a boiling point above 175° C. (diesel fraction), which is introduced into a second hydrocracking step b''). The second hydrocracking step b'') comprises a dedicated second hydrocracking reaction section different from the first hydrocracking reaction section b'). This configuration is particularly suitable when it is desired to produce only a naphtha fraction.

[0112] The second hydrocracking step b″) is carried out in a hydrocracking reaction section using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, said hydrocracking reaction section being fed at least with the fraction containing compounds having a boiling point above 175° C. obtained from step d) and with a gas stream containing hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450° C., with a partial pressure of hydrogen between 1.5 and 20.0 MPa (absolute) and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrocracked effluent, which is sent to a separation step c). Suitable operating conditions and catalysts used in the second hydrocracking step are those described for the first hydrocracking step. The operating conditions and catalysts used in the two hydrocracking steps may be the same or different.

[0113] The second hydrocracking step is preferably carried out in a hydrocracking reaction section comprising at least one, preferably 1 to 5, fixed bed reactors comprising n catalyst beds, n being an integer equal to or greater than 1, preferably between 1 and 10, preferably between 2 and 5, and each of said bed(s) comprising at least one, and preferably not more than 10, types of hydrocracking catalyst.

[0114] These operating conditions used in the hydrocracking step(s) generally make it possible to obtain a conversion per pass of more than 15% by weight, even more preferably between 20 and 95% by weight, to a product having a minimum of 80% by volume of compounds with a boiling point below 175° C., preferably below 160° C., preferably below 150° C. If the process is carried out in two hydrocracking steps, the conversion per pass in the second step is kept moderate, maximizing the selectivity for compounds of the naphtha fraction (boiling point below 175° C., in particular between 80° C. and 175° C.). The conversion per pass is limited by the use of a high recycle ratio over the second hydrocracking step loop. This ratio is defined as the feed flow rate of step b″) to the flow rate of the feedstock of step a); preferentially, this ratio is between 0.2 and 4, preferably between 0.5 and 2.5.

[0115] By means of the hydrocracking step(s), it is therefore not always possible to convert all of the compounds with a boiling point above 175° C. (diesel fraction) into compounds with a boiling point below 175° C. (naphtha fraction). After the fractionation step d), a more or less significant proportion of compounds with a boiling point above 175° C. may therefore remain. To increase the conversion, at least a part of this unconverted fraction can be recycled to step b') as described below or else sent to a second hydrocracking step b''). Another part can be purged. Depending on the operating conditions of the process, said purging can be between 0 and 10% by weight, preferably between 0.5 and 5% by weight, of the fraction containing compounds with a boiling point above 175° C. relative to the incoming feedstock.

[0116] According to the invention, the hydrocracking step(s) is / are operated in the presence of at least one hydrocracking catalyst.

[0117] The hydrocracking catalyst(s) used in the hydrocracking step(s) are conventional hydrocracking catalysts known to those skilled in the art and are of the bifunctional type combining acid functional groups with hydrodehydrogenation functional groups and optionally at least one binder matrix. The acid functional groups are provided with a large surface area (typically 150-800 m2) with surface acidity. 2 / g), such as halogenated (especially chlorinated or fluorinated) aluminas, combinations of oxides of boron and aluminum, amorphous silica-alumina and zeolites. The hydrodehydrogenation functional groups are provided by at least one metal from group VIB and / or at least one metal from group VIII of the periodic table.

[0118] Preferably, the hydrocracking catalyst(s) comprises a hydrodehydrogenation functional group, which comprises at least one metal from group VIII, which is selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, preferably from cobalt and nickel. Preferably, the catalyst(s) also comprises at least one metal from group VIB, which is selected from chromium, molybdenum and tungsten, either alone or in a mixture, preferably from molybdenum and tungsten. Hydrodehydrogenation functional groups of the NiMo, NiMoW or NiW type are suitable.

[0119] Preferably, the content of metal from group VIII in the hydrocracking catalyst(s) is advantageously between 0.5% and 15% by weight, preferably between 1% and 10% by weight, the percentages being expressed as percentages by weight of the oxide relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO, respectively.

[0120] Preferably, the content of metal from group VIB in the hydrocracking catalyst(s) is advantageously between 5% and 35% by weight, preferably between 10% and 30% by weight, the percentages being expressed as percentages by weight of the oxide relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3, WO3, respectively.

[0121] The hydrocracking catalyst(s) may optionally comprise at least one promoter element, deposited on the catalyst and selected from the group formed by phosphorus, boron and silicon, optionally comprising at least one element from group VIIA (preferably chlorine and fluorine), optionally at least one element from group VIIB (preferably manganese) and optionally at least one element from group VB (preferably niobium).

[0122] Preferably, the hydrocracking catalyst(s) comprises at least one amorphous or poorly crystallized porous mineral matrix of the oxide type, chosen from alumina, silica, silica-alumina, aluminates, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide or clays, alone or as a mixture, and preferably chosen from alumina or silica-alumina, alone or as a mixture.

[0123] Preferably, the silica-alumina contains more than 50% by weight of alumina, preferably more than 60% by weight of alumina.

[0124] Preferably, the hydrocracking catalyst(s) also optionally comprises a zeolite, which is selected from Y zeolites, preferably from USY zeolites, alone or in combination with other zeolites, the other zeolites being selected from among Beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 or ZBM-30 zeolites, alone or as a mixture. Preferably, the zeolite is USY zeolite alone.

[0125] When said catalyst comprises a zeolite, the content of zeolite in the hydrocracking catalyst(s) is advantageously between 0.1% and 80% by weight, preferably between 3% and 70% by weight, the percentages being expressed as the percentage of zeolite relative to the total weight of the catalyst.

[0126] Suitable catalysts comprise, preferably consist of, at least one metal from Group VIB and optionally at least one non-noble metal from Group VIII, at least one promoter element, preferably phosphorus, at least one Y zeolite and at least one alumina binder.

[0127] Even more preferred catalysts comprise, and preferably consist of, nickel, molybdenum, phosphorus, USY zeolite, and optionally betaolite, and alumina.

[0128] Other suitable catalysts include, and preferably consist of, nickel, tungsten, alumina and silica-alumina.

[0129] Other suitable catalysts include, and preferably consist of, nickel, tungsten, USY zeolite, alumina and silica-alumina.

[0130] The hydrocracking catalyst is, for example, in the form of extrudates.

[0131] In one variant, the hydrocracking catalyst used in step b'') comprises a hydrodehydrogenation functional group containing at least one noble metal from group VIII chosen from palladium and platinum, either alone or in a mixture. The content of noble metal from group VIII is advantageously between 0.01% and 5% by weight, preferably between 0.05% and 3% by weight, the percentages being expressed as percentages by weight of oxide (PtO or PdO) relative to the total weight of the catalyst.

[0132] According to another aspect of the present invention, the above-mentioned hydrogenolysis catalyst also contains one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are often referred to by the term "additive catalyst". In general, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide functional groups, or from compounds containing a furan ring, or from sugars.

[0133] The preparation of the catalysts for steps a), b), b') or b'') is known and generally comprises a step of impregnation on the support of the group VIII metal and the group VIB metal, if present, and optionally phosphorus and / or boron, followed by drying and then optionally calcination. In the case of additive type catalysts, the preparation is generally carried out by simple drying without calcination after the introduction of the organic compound. The term "calcination" here means a heat treatment at a temperature of 200° C. or higher under air or a gas containing oxygen. Before their use in the process steps, the catalysts are generally subjected to sulfurization to form the active species. The catalysts of step a) may also be catalysts used in their reduced form, thus comprising a reduction step during their preparation.

[0134] The hydrogen-containing gas streams fed to the reaction section of step a), b), b') or b'') may consist of hydrogen feed and / or recycled hydrogen, in particular obtained from the separation step c). Preferably, additional gas streams containing hydrogen are advantageously introduced at the inlet of each reactor, in particular of reactors operated in series, and / or at the inlet of each catalyst bed from the second catalyst bed of the reaction section. These additional gas streams are also called cooling streams. They make it possible to control the temperature in the reactors, where the reactions involved are generally highly exothermic.

[0135] Optionally, each of steps a), b), b') or b'') may employ a heating section located upstream of the reaction section, in which the incoming effluent is heated to reach an appropriate temperature. Said optional heating section may therefore preferably comprise one or more exchangers, preferably those allowing heat exchange between the hydrotreated effluent and the hydrocracked effluent, and / or a preheating oven.

[0136] However, by carrying out step a) at a relatively high average temperature with an increasing temperature profile, it is possible in some cases to eliminate the need for a heating device or at least reduce the heat requirement between the hydrotreating catalyst section of step a) and the hydrotreating catalyst section of step b).

[0137] (Separation step c)) According to the invention, the treatment process comprises a separation step c), which is advantageously carried out in at least one washing / separation section to which is fed at least the hydrotreated effluent obtained from step b) or the hydrocracked effluent obtained from the optional steps b') and b'') and an aqueous solution, in order to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon-based effluent.

[0138] The gaseous effluent obtained on the conclusion of step c) advantageously comprises hydrogen, preferably at least 80% by volume, preferably at least 85% by volume of hydrogen. Advantageously, said gaseous effluent may be at least partially recycled to the hydrogenation step a) and / or the hydrotreating step b) and / or the hydrocracking step b') and / or the hydrocracking step b''), the recycle system optionally comprising a purification section.

[0139] The aqueous effluent obtained at the end of step c) advantageously contains ammonium salts and / or hydrochloric acid.

[0140] Ammonium chloride salts are generated by reaction of the chloride ions, particularly in the form of HCl, released by hydrogenation of the chlorinated compounds during steps a) and b) and subsequently dissolved in water, with the ammonium ions, which arise during step b) by hydrogenation of the nitrogen compounds, particularly in the form of NH3, and / or are provided by injection of the amine and its subsequent dissolution in water. This separation step d) makes it possible in particular to remove this ammonium chloride salt and therefore to limit the risk of clogging due to its precipitation, in particular in the transfer lines and / or in the sections of the method according to the invention and / or in the transfer lines to the steam cracker. It also makes it possible to remove the hydrochloric acid formed by the reaction of the hydrogen ions with the chloride ions.

[0141] Depending on the content of chlorinated compounds in the initial feedstock to be treated, a stream containing amines, for example monoethanolamine, diethanolamine and / or monodiethanolamine, may be injected upstream of the hydrogenation step a) and / or between the hydrogenation step a) and the hydrotreating step b) and / or between the hydrocracking step b') and the separation step c), preferably upstream of the hydrogenation step a), to ensure a sufficient amount of ammonium ions to combine with the chloride ions formed during the hydrotreating step, thus making it possible to limit the formation of hydrochloric acid and therefore the corrosion downstream of the separation section.

[0142] Advantageously, separation step c) comprises the injection of an aqueous solution, preferably water, into the hydrotreated effluent obtained from step b) or into the hydrocracked effluent obtained from optional steps b') and b''), upstream of the washing / separation section, to at least partially dissolve the ammonium chloride salts and / or hydrochloric acid, thus improving the removal of chlorinated impurities and therefore reducing the risk of clogging caused by the accumulation of ammonium chloride salts.

[0143] The temperature at which separation step c) is advantageously carried out is between 50 and 450° C., preferentially between 100 and 440° C., preferably between 200 and 420° C. It is important to carry out said step in this temperature range (and therefore not to cool the hydroconverted effluent too much) due to the risk of blockages in the lines due to deposition of ammonium chloride salts. Advantageously, separation step c) is carried out at a pressure close to that used in steps a) and / or b), preferably between 1.0 and 20.0 MPa, to facilitate the recycling of hydrogen.

[0144] The washing / separation section of step c) may be at least partially carried out in common or separate washing and separation equipment, which are well known (separation vessels, pumps, heat exchangers, washing columns, etc. which may be operated at various pressures and temperatures).

[0145] In one optional embodiment of the invention, separation step c) comprises the injection of an aqueous solution into the hydrotreated effluent obtained from step b), followed by a washing / separation section, advantageously comprising separate phases to obtain at least one aqueous effluent containing ammonium salts, a washed liquid hydrocarbon-based effluent and a partially washed gaseous effluent. The aqueous effluent containing ammonium salts and the washed liquid hydrocarbon-based effluent may then be separated in a decanting vessel to obtain said hydrocarbon-based effluent and said aqueous effluent. The partially washed gaseous effluent may be introduced in parallel into a washing column, where it flows countercurrently relative to an aqueous stream, preferably of the same nature as the aqueous solution injected into the hydrotreated effluent, thereby making it possible to at least partially, preferably completely, remove the hydrochloric acid contained in the partially washed gaseous effluent and thus obtain said gaseous effluent, preferably said gaseous effluent essentially containing hydrogen, and an acidic aqueous stream. The aqueous effluent obtained from the decanting vessel may optionally be mixed with the acidic aqueous stream and optionally used, as a mixture with the acidic aqueous stream, in a water recycle circuit and fed to the aqueous solution upstream of the washing / separation section and / or to the aqueous stream in a washing column, step c) of separation. The water recycle circuit may include a supply of water and / or a basic solution and / or a purge to remove dissolved salts.

[0146] In another optional embodiment of the invention, separation step c) may advantageously comprise a "high pressure" washing / separation section, which operates at a pressure close to that of the hydrogenation step a) and / or the hydrotreating step b) and / or the optional hydrocracking step b'), preferably between 1.0 and 20.0 MPa, to facilitate the recycling of hydrogen. This optional "high pressure" section of step c) may be completed with a "low pressure" section to obtain a hydrocarbon-based liquid fraction free of the portion of gas dissolved at high pressure and intended to be directly processed in a steam cracking process or optionally sent to fractionation step d).

[0147] The gas fraction(s) obtained from separation step c) may undergo further purification(s) and separation(s) with the aim of recovering at least one hydrogen-rich gas and / or liquid hydrocarbons, in particular ethane, propane and butanes, the hydrogen-rich gases may be recycled upstream of steps a) and / or b) and / or b') and / or b''), and the liquid hydrocarbons may advantageously be sent, separately or as a mixture, to one or more furnaces of a steam cracking step e) in order to increase the overall yield of olefins.

[0148] The hydrocarbon-based effluent obtained from the separation step c) is either partially or totally sent directly to the inlet of the steam cracking unit or sent to an optional fractionation step d). Preferably, the hydrocarbon-based liquid effluent is partially or totally, preferably totally, sent to fractionation step d).

[0149] (Fractionation step d) (optional) The process according to the invention may comprise a step of fractionating all or part, preferably all, of the hydrocarbon-based effluent obtained from step c) to obtain at least one gas stream and at least two liquid hydrocarbon-based streams, said two liquid hydrocarbon-based streams being at least one naphtha fraction comprising compounds having a boiling point below 175°C, in particular between 80 and 175°C, and at least one hydrocarbon fraction comprising compounds having a boiling point above 175°C.

[0150] Step d) makes it possible in particular to remove gases dissolved in the hydrocarbon-based liquid effluent, such as ammonia, hydrogen sulfide and light hydrocarbons containing 1 to 4 carbon atoms.

[0151] The optional fractionation step d) is advantageously carried out at a pressure below 1.0 MPa (absolute), preferably between 0.1 and 1.0 MPa (absolute).

[0152] According to one embodiment, step d) may be carried out in a section advantageously comprising at least one stripping tower equipped with a reflux circuit comprising a reflux vessel. Said stripping tower is fed with the hydrocarbon-based liquid effluent obtained from step c) and with a steam stream. The hydrocarbon-based liquid effluent obtained from step c) may optionally be heated before entering the stripping tower. The lightest compounds are therefore entrained at the top of the tower and conveyed to a reflux circuit comprising a reflux vessel where gas / liquid separation takes place. The gas phase comprising the light hydrocarbons is withdrawn as a gas stream from the reflux vessel. The naphtha fraction comprising compounds with a boiling point below 175° C. is advantageously withdrawn from the reflux vessel. The hydrocarbon fraction comprising compounds with a boiling point above 175° C. is advantageously withdrawn at the bottom of the stripping tower.

[0153] According to another embodiment, the fractionation step d) may comprise a stripping column followed by a distillation column or a distillation column only.

[0154] The naphtha fraction containing compounds with a boiling point of 175° C. or less and the fraction containing compounds with a boiling point of more than 175° C. may optionally be mixed and sent in whole or in part to a steam cracking unit, at the outlet of which olefins may be (re)formed and participate in the formation of polymers. Preferably, only a portion of said fraction(s) is sent to the steam cracking unit; at least a portion of the remaining portion is optionally recycled to at least one of the steps of the method and / or sent to a fuel storage unit, such as a naphtha storage unit, a diesel storage unit or a kerosene storage unit, obtained from conventional petroleum-based feedstocks.

[0155] According to a preferred embodiment, the naphtha fraction comprising compounds with a boiling point below 175° C. is sent, in whole or in part, to a steam cracking unit, while the fraction comprising compounds with a boiling point above 175° C. is recycled to steps a) and / or b) and / or b') and / or sent to a fuel storage unit.

[0156] In one particular embodiment, the optional fractionation step d) may make it possible to obtain, besides the gas stream, a naphtha fraction comprising compounds with a boiling point below 175° C., preferably between 80 and 175° C., a middle distillate fraction comprising compounds with a boiling point above 175° C. and below 385° C., and a hydrocarbon fraction comprising compounds with a boiling point above 385° C., known as the heavy hydrocarbon fraction. The naphtha fraction may be sent, in whole or in part, to a steam cracking unit and / or to a storage unit for naphtha obtained from conventional petroleum-based feedstocks; it may be recycled; the middle distillate may be sent, in whole or in part, to either a steam cracking unit or to a storage unit for diesel obtained from conventional petroleum-based feedstocks or may be recycled; the heavy fraction may be sent, for its part, at least in part, to the hydrocracking step f) or may be recycled.

[0157] In another particular embodiment, the optional fractionation step e) may make it possible to obtain, in addition to the gas stream, a naphtha fraction comprising compounds having a boiling point less than or equal to 175° C., preferably between 80 and 175° C., a kerosene fraction comprising compounds having a boiling point greater than 175° C. and less than or equal to 280° C., a diesel fraction comprising compounds having a boiling point greater than 280° C. and less than 385° C., and a hydrocarbon fraction comprising compounds having a boiling point greater than or equal to 385° C., known as the heavy hydrocarbon fraction. The naphtha fraction may be sent, in whole or in part, to a steam cracking unit and / or to a naphtha pool obtained from conventional petroleum-based feedstocks; it may be sent to a recycling step g); the kerosene fraction and / or diesel fraction may be sent, in whole or in part, either to a steam cracking unit or to a pool of kerosene or diesel obtained, respectively, from conventional petroleum-based feedstocks or may be sent to a recycling step f); the heavy fraction may, for its part, at least in part, be sent to a steam cracking unit or may be sent to a recycling step f).

[0158] In another particular embodiment, the naphtha fraction containing compounds having a boiling point of 175° C. or less obtained from step d) is fractionated into a heavy naphtha fraction containing compounds having a boiling point of 80-175° C. and a light naphtha fraction containing compounds having a boiling point of less than 80° C., and at least a portion of the heavy naphtha fraction is sent to an aromatic complex including at least one naphtha reforming step for producing aromatic compounds. According to this embodiment, at least a portion of the light naphtha fraction is sent to the steam cracking step e) described below.

[0159] The gas fraction(s) obtained from the fractionation step d) may undergo additional purification(s) and separation(s) with the aim of recovering at least the light hydrocarbons, in particular ethane, propane and butanes, which may advantageously be sent, separately or as a mixture, to one of the furnaces of the steam cracking step e) in order to increase the overall yield of olefins.

[0160] (Recycling of fractions containing compounds with boiling points above 175°C) At least a portion of the fraction comprising compounds with a boiling point above 175° C. obtained from fractionation step d) can be recovered and constitute a recycle stream which is sent upstream of at least one of the reaction steps of the process according to the invention or directly, in particular to the hydrogenation step a) and / or the hydrotreating step b) and / or the hydrocracking step b'). Optionally, part of the recycle stream may be sent to the optional step a0).

[0161] The recycle stream may be fed to said reaction steps a) and / or b) and / or b') in one injection or may be split into several fractions and fed to reaction steps a) and / or b) and / or b') in multiple injections, i.e. to different catalyst beds.

[0162] Advantageously, the amount of the recycle stream of the fraction containing compounds with a boiling point above 175° C. is adjusted so that the weight ratio between the recycle stream and the feedstock containing plastic pyrolysis oil, i.e. the feedstock to be treated and fed to the overall process, is less than or equal to 10, preferably less than or equal to 5, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, preferably greater than or equal to 0.1. Highly preferably, the amount of the recycle stream is adjusted so that the weight ratio between the recycle stream and the feedstock containing plastic pyrolysis oil is between 0.2 and 5.

[0163] According to one preferred variant, at least a portion of the fraction comprising compounds with a boiling point above 175° C. obtained from fractionation step d), if any, is sent to hydrocracking step b'). Recycling a portion of the fraction comprising compounds with a boiling point above 175° C. to at least one of the reaction steps of the process according to the invention or upstream thereof, in particular to hydrocracking step b'), advantageously makes it possible to increase the yield of naphtha fractions with a boiling point below 175° C. Recycling also makes it possible to dilute impurities and to control the temperature in the reaction step(s) in which the reactions involved may be highly exothermic.

[0164] According to another preferred variant, at least a portion of the fraction comprising compounds with a boiling point above 175° C. obtained from fractionation step d) is sent to a second hydrocracking step b″), if present.

[0165] A purge may be provided for recycling the fraction containing compounds with a boiling point above 175° C. Depending on the operating conditions of the process, said purge may be 0-10% by weight, preferably 0.5-5% by weight, of the fraction containing compounds with a boiling point above 175° C. relative to the incoming feedstock.

[0166] (Recycling of the hydrocarbon-based effluent obtained from step c) and / or the naphtha fraction having a boiling point of 175° C. or less obtained from step d)) A portion of the hydrocarbon-based effluent obtained from the separation step c) or a portion of the naphtha fraction with a boiling point below 175° C. obtained from the optional fractionation step d) may be recovered and constitute a recycle stream. The recycle stream is sent upstream of or directly to at least one of the reaction steps of the process according to the invention, in particular to the hydrogenation step a) and / or the hydrotreatment step b). Optionally, a fraction of the recycle stream may be sent to the optional pretreatment step a0).

[0167] Preferably, at least a portion of the hydrocarbon-based effluent obtained from the separation step c) or the naphtha cut having a boiling point below 175° C. obtained from the optional fractionation step d) is fed to the hydrotreatment step b).

[0168] Advantageously, the amount of the recycle stream, i.e. the fraction of the recycle product obtained, is adjusted so that the weight ratio between the recycle stream and the feedstock comprising plastic pyrolysis oil, i.e. the feedstock to be treated and fed to the overall process, is less than or equal to 10, preferably less than or equal to 5, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, preferably greater than or equal to 0.1. Highly preferably, the amount of the recycle stream is adjusted so that the weight ratio between the recycle stream and the feedstock comprising plastic pyrolysis oil is between 0.2 and 5.

[0169] Advantageously, at the start of the process, a hydrocarbon fraction external to the process may be used as a recycle stream. The person skilled in the art will know how to choose said hydrocarbon fraction.

[0170] Recycling a portion of the product obtained to or upstream of at least one of the reaction steps of the process according to the invention advantageously makes it possible, firstly, to dilute impurities and, secondly, to control the temperature during the reaction step(s) involved, in which the reactions may be highly exothermic.

[0171] The hydrocarbon-based effluent or the hydrocarbon-based stream(s) thus obtained by the treatment of plastic pyrolysis oil by the method of the present invention has a composition that is capable of meeting the specifications for the feedstock entering the steam cracking unit. In particular, the composition of the hydrocarbon-based effluent or the hydrocarbon-based stream(s) is preferably such that: the total content of metallic elements is less than or equal to 5.0 ppm by weight, preferably less than or equal to 2.0 ppm by weight, preferentially less than or equal to 1.0 ppm by weight, preferably less than or equal to 0.5 ppm by weight, with The content of silicon element (Si) is 1.0 ppm by weight or less, preferably 0.6 ppm by weight or less; The content of iron element (Fe) is 100 ppb by weight or less, the sulfur content is less than or equal to 500 ppm by weight, preferably less than or equal to 200 ppm by weight; the nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, preferably less than or equal to 5 ppm by weight; - the asphaltene content is less than 5.0 ppm by weight; the total content of elemental chlorine is less than or equal to 10 ppm by weight, preferably less than 1.0 ppm by weight; the content of olefinic compounds (mono- and diolefins) is less than or equal to 5.0% by weight, preferably less than or equal to 2.0% by weight, preferably less than or equal to 0.1% by weight;

[0172] The content is given as the relative weight concentration relative to the total weight of the stream under consideration, weight percentage (%), parts per million (ppm) or parts per billion (ppb).

[0173] The method according to the invention thus makes it possible to treat plastic pyrolysis oil so as to obtain an effluent which can be injected totally or partly into a steam cracking unit.

[0174] (Step e) of steam cracking (optional) The hydrocarbon-based effluent obtained from the separation step c) or at least one of the two liquid hydrocarbon-based streams obtained from the optional step d) may be sent in whole or in part to a steam cracking step e).

[0175] Advantageously, the gas fraction(s) obtained from the separation step c) and / or the fractionation step d) containing ethane, propane and butane may be sent, in whole or in part, to a steam cracking step e).

[0176] Said steam cracking step e) is advantageously carried out in at least one pyrolysis furnace at temperatures between 700 and 900°C, preferably between 750 and 850°C, and at pressures between 0.05 and 0.3 MPa (relative). The residence time of the hydrocarbon-based compounds is generally less than or equal to 1.0 second (denoted s), preferably between 0.1 and 0.5 s. Steam is advantageously introduced upstream of the optional steam cracking step e), after separation (or fractionation). The amount of water introduced, advantageously in the form of steam, is advantageously between 0.3 and 3.0 kg of water per kg of weight of hydrocarbon-based compounds entering step e). The optional step e) is preferably carried out in several pyrolysis furnaces in parallel, adapting the operating conditions to the various streams feeding step e), in particular the streams obtained from step d), and managing the decoking times of the tubes. The furnace comprises one or several tubes arranged in parallel. The furnace may also represent a group of furnaces operating in parallel. For example, a furnace may be dedicated to cracking a naphtha fraction containing compounds with boiling points below 175°C.

[0177] The effluents from the various steam cracking furnaces are generally recombined before separation to constitute the effluent. It is understood that the steam cracking step e) includes not only the steam cracking furnace but also sub-steps related to steam cracking that are well known to the person skilled in the art. These sub-steps may include, inter alia, heat exchangers, columns and catalytic reactors and recycle to the furnaces. The columns make it possible to fractionate the effluent with the aim of recovering at least one light fraction, which generally comprises hydrogen and compounds containing 2 to 5 carbon atoms, a fraction comprising pyrolysis gasoline and possibly a fraction comprising pyrolysis oil. The columns make it possible to separate the various components of the fractionated light fraction in order to recover at least one fraction rich in ethylene (C2 fraction), a fraction rich in propylene (C3 fraction) and possibly a fraction rich in butenes (C4 fraction). The catalytic reactors make it possible, inter alia, to carry out the hydrogenation of the C2, C3 and also C4 fractions and pyrolysis gasoline. Saturated compounds, especially those containing from 2 to 4 carbon atoms, are advantageously recycled to the steam cracker to increase the overall yield of olefins.

[0178] This steam cracking step e) makes it possible to obtain at least one effluent containing a satisfactory content of olefins containing 2, 3 and / or 4 carbon atoms (i.e. C2, C3 and / or C4 olefins), in particular a content of 30% by weight or more, in particular 40% by weight or more, or even 50% by weight or more, of all olefins containing 2, 3 and 4 carbon atoms relative to the weight of the steam cracking effluent under consideration. Said C2, C3 and C4 olefins may advantageously be used as polyolefin monomers.

[0179] According to one preferred embodiment of the present invention, the method for processing a feedstock containing plastic pyrolysis oil comprises, and preferably consists of, a sequence of steps as follows, preferably in the given order: a) a hydrogenation step, b) a hydrotreating step, c) a separation step, or a hydrogenation step a), a hydrotreating step b), a separation step c) and a fractionation step d), or - a hydrogenation step a), a hydrotreating step b), a separation step c), a fractionation step d) and recycling the fraction comprising compounds having a boiling point below 175° C. to steps a) and / or b), a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), or a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c) and a fractionation step d), or - a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), a fractionation step d) and recycling the fraction comprising compounds having a boiling point above 175° C. to the hydrocracking step b'), or - a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), a fractionation step d) and recycling the fraction comprising compounds having a boiling point below 175° C. to step a) or b), or - a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), a fractionation step d), a step of recycling the fraction comprising compounds having a boiling point above 175° C. to the hydrocracking step b') and a step of recycling the fraction comprising compounds having a boiling point below 175° C. to step a) or b), or a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), a fractionation step d), recycling the fraction comprising compounds having a boiling point above 175° C. to the hydrocracking step b'), or a hydrogenation step a), a hydrotreating step b), a hydrocracking step b'), a separation step c), a fractionation step d), a step of recycling the fraction comprising compounds having a boiling point above 175° C. to the hydrocracking step b') and a step of recycling the fraction comprising compounds having a boiling point below 175° C. to step a) or b), or a hydrogenation step a), a hydrotreating step b), a separation step c), a fractionation step d) and a hydrocracking step b'), or a hydrogenation step a), a hydrotreating step b), a separation step c), a fractionation step d) and a hydrocracking step b'), with the effluent from step b') being recycled to step c), or - the hydrogenation step a), the hydrotreating step b), the separation step c), the fractionation step d) and the hydrocracking step b') and recycling the effluents from step b') to step c) and recycling the fractions comprising compounds having a boiling point below 175°C to step a) or b).

[0180] All embodiments may further comprise, and preferably consist of, a pretreatment step a0).

[0181] All embodiments may further comprise, and preferably consist of, a steam cracking step g).

[0182] (Analysis methods used) The analytical methods and / or standards used to determine the characteristics of the various streams, in particular the characteristics of the feedstock to be treated and the effluent, are known to the person skilled in the art. They are listed below, in particular for information. Other reputable equivalent methods may also be used, in particular equivalent IP, EN or ISO methods.

[0183] [Table 1]

[0184] (1) MAV method; described in the following literature: C. Lopez-Garcia et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil & Gas Science and Technology - Rev. IFP, volume 62 (2007), No. 1, 57-68 (List of Drawings) The information regarding the elements referenced in Figures 1-2 allows a better understanding of the present invention, but the invention is not limited to the specific embodiments shown in Figures 1-2. The various embodiments presented may be used alone or in combination with each other, and there is no limitation on the combinations.

[0185] FIG. 1 represents a scheme of a particular embodiment of the method of the invention, comprising the following steps: - a step a of hydrogenation of a hydrocarbon-based feedstock (1) obtained from the pyrolysis of plastics; carried out in at least one fixed-bed reactor comprising at least one hydrogenation catalyst, in the presence of a hydrogen-rich gas (2) and, optionally, in the presence of an amine provided by stream (3); obtaining an effluent (4); - a step b of hydrotreating the effluent (4) obtained from step a), carried out in the presence of hydrogen (5) in at least one fixed bed reactor comprising at least one hydrotreating catalyst; obtaining a hydrotreated effluent (6); - an optional step b' of hydrocracking the effluent (6) obtained from step b), carried out in at least one fixed-bed reactor comprising at least one hydrocracking catalyst in the presence of hydrogen (7); obtaining a hydrocracked effluent (8); - a step c of separation of the effluent (8); carried out in the presence of an aqueous wash solution (9); making it possible to obtain at least one fraction (10) containing hydrogen, an aqueous fraction (11) containing dissolved salts and a hydrocarbon-based liquid fraction (12); - an optional step d of fractionation of the hydrocarbon-based liquid fraction (12); making it possible to obtain at least one gas fraction (13) and a fraction comprising compounds with a boiling point below 175° C. (naphtha fraction) (14) and a fraction comprising compounds with a boiling point above 175° C. (diesel fraction) (15).

[0186] At the end of step d), at least a portion of the fraction (14) comprising compounds with a boiling point below 175° C. is sent to a steam cracking process (not shown). Another part of fraction (14) is fed to the hydrogenation step a) (fraction (14a)) and to the hydrotreating step b) (fraction (14b)). A part of the fraction (15) comprising compounds with a boiling point above 175° C. obtained from step d) is fed to the hydrocracking step b') (fraction (15a)), while another part (15b) constitutes the purge.

[0187] Figure 2 represents the scheme of another particular embodiment of the process of the invention, which is based on the scheme of figure 1. This scheme comprises, inter alia, a second hydrocracking step b'') in which the fraction (15) containing compounds with a boiling point above 175°C obtained from step d) is fed (fraction (15a)) to this second hydrocracking step b'', which is carried out in at least one fixed bed reactor containing at least one hydrocracking catalyst and fed with hydrogen (16). The second hydrocracked effluent (17) is recycled to the separation step c). The other part of fraction (15) constitutes the purge (15b).

[0188] Instead of injecting the amine stream (3) at the inlet of the hydrogenation step a), it is possible, depending on the characteristics of the feedstock, to inject it at the inlet of the hydrotreating step b), at the inlet of the hydrocracking step b'), at the inlet of the separation step c) or also not to inject it.

[0189] Only the main steps are shown in Figures 1 and 2 together with the main flows in order to allow a better understanding of the invention. It is clearly understood that all the equipment required for the functioning (vessels, pumps, exchangers, furnaces, columns, etc.) is present, even if not shown. It is also understood that a hydrogen-rich gas stream (feed or recycle) may be injected at the inlet of each reactor or catalyst bed, or between two reactors or two catalyst beds, as described above. Means for purifying and recycling hydrogen that are well known to those skilled in the art may be used.

[0190] Example 1 (Example 1 (according to the present invention)) The feedstock (1) treated in the present process is plastic pyrolysis oil (i.e., containing 100% by weight of said plastic pyrolysis oil) and has the characteristics shown in Table 2.

[0191] [Table 2]

[0192] (1) The MAV method is described in the following article: C. Lopez-Garcia et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil & Gas Science and Technology - Rev. IFP, Vol. 62 (2007), No. 1, pages 57-68

[0193] The feedstock (1) is subjected to a hydrogenation step a) which is carried out in a fixed bed reactor in the presence of hydrogen (2) and a hydrogenation catalyst of the NiMo type supported on alumina under the conditions shown in Table 3.

[0194] [Table 3]

[0195] The conditions shown in Table 3 correspond to those at the start of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0196] At the end of the hydrogenation step a), the observed conversions (=(initial concentration-final concentration) / initial concentration) are given in Table 4.

[0197] [Table 4]

[0198] The effluent (4) obtained from the hydrogenation step a) is subjected directly, without separation, to a hydrotreating step b), which is carried out in a fixed bed, in the presence of hydrogen (5) and a hydrotreating catalyst of the NiMo type supported on alumina, under the conditions shown in Table 5.

[0199] [Table 5]

[0200] The conditions shown in Table 5 correspond to those at the start of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0201] The effluent (6) obtained from the hydrotreating step b) is subjected to a separation step c); a stream of water is injected into the effluent obtained from the hydrotreating step b); the mixture is then treated in an acid gas washing column and a separation vessel so as to obtain a gas fraction and a liquid effluent. The yields for the various fractions obtained after separation are indicated in Table 6 (the yields correspond to the ratio of the mass of the various products relative to the mass of the feedstock upstream of step a), expressed as a percentage and denoted as %m / m).

[0202] [Table 6]

[0203] All or a portion of the resulting liquid fraction may then be upgraded in a steam cracking process to form olefins which may then be polymerized to form recycled plastics.

[0204] The process carried out according to the invention results in reduced catalyst deactivation during the hydrogenation step a) and during the hydrotreating step b) relative to the catalyst deactivation observed with the prior art.

[0205] (Example 2 (not in accordance with the present invention)) In this example, which is consistent with the prior art but not with the present invention, the feedstock to be treated is the same as that described in Example 1 (see Table 2).

[0206] The feedstock is subjected to a selective hydrogenation step a), which is carried out in a fixed bed reactor in the presence of hydrogen and a selective hydrogenation catalyst of the NiMo type supported on alumina under the conditions shown in Table 7.

[0207] [Table 7]

[0208] The conditions indicated in Table 7 correspond to the conditions at the start of the cycle, with the average temperature (WABT) increased by 4° C. per month to compensate for catalyst deactivation.

[0209] At the end of the selective hydrogenation step a), the observed conversions (=(initial concentration-final concentration) / initial concentration) are indicated in Table 8.

[0210] [Table 8]

[0211] The effluent obtained from the selective hydrogenation step a) is subjected directly, without separation, to a hydrotreating step b), which is carried out in a fixed bed in the presence of hydrogen, a hydrocarbon-based recycle stream and an alumina-supported NiMo type hydrotreating catalyst under the conditions presented in Table 9.

[0212] [Table 9]

[0213] The conditions indicated in Table 9 correspond to the conditions at the start of the cycle, with the average temperature (WABT) increased by 2° C. per month to compensate for catalyst deactivation.

[0214] The effluent obtained from the hydrotreating step b) is subjected to a separation step c): a water stream is injected into the effluent obtained from the hydrotreating step b); the mixture is then treated in an acid gas washing column and a separation vessel so as to obtain a gas fraction and a liquid effluent. The yields for the various fractions obtained after separation are indicated in Table 10 (the yields correspond to the ratio of the amount of the mass of the various obtained products relative to the mass of the feedstock upstream of step a), expressed as a percentage and denoted as %m / m).

[0215] [Table 10]

[0216] Processes carried out according to the prior art and not according to the invention result in a greater catalyst deactivation during the selective hydrogenation step a) and during the hydrotreating step b) than is observed in processes carried out according to the invention during the hydrogenation step a) and during the hydrotreating step b). [Brief description of the drawings]

[0217] [Figure 1] 1 represents a scheme of a particular embodiment of the method of the present invention. [Diagram 2] 1 represents a scheme of another particular embodiment of the method of the invention, based on the scheme of FIG. 1.

Claims

1. 1. A method for treating a feedstock containing plastic pyrolysis oil, comprising the steps of: a) a hydrogenation step carried out in a hydrogenation reaction section, using at least one fixed bed reactor, the fixed bed reactor containing n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrogenation catalyst, the hydrogenation reaction section being fed with at least the feedstock and a gas stream containing hydrogen, the hydrogenation reaction section being used at an average temperature of 140-400° C., the partial pressure of hydrogen being 1.0-10.0 MPa (absolute), and the hourly space velocity being 0.1-10.0 h －１ and the outlet temperature of the reaction section of step a) is at least 15° C. higher than the inlet temperature of the reaction section of step a); obtaining a hydrogenated effluent. b) a hydrotreating step carried out in a hydrotreating reaction section, using at least one fixed bed reactor containing n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst, to which at least the hydrogenated effluent from step a) and a gas stream containing hydrogen are fed, the average temperature during which the hydrotreating reaction section is between 250 and 430° C., the partial pressure of hydrogen is between 1.0 and 10.0 MPa (absolute), and the hourly space velocity is between 0.1 and 10.0 h －１ and the average temperature of the reaction section of step b) is higher than the average temperature of the hydrotreating reaction section of step a); obtaining a hydrotreated effluent. b') an optional hydrocracking step, carried out in a hydrocracking reaction section, using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, to which the hydrotreated effluent from step b) and / or the fraction from step d) containing compounds with a boiling point above 175°C and a gas stream containing hydrogen are fed, the average temperature in the hydrocracking reaction section being between 250 and 450°C, the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute), and the hourly space velocity being between 0.1 and 10.0 h －１ obtaining a hydrocracked effluent which is sent to a separation step c); c) a separation step, feeding the hydrotreated effluent from step b) or the hydrocracked effluent from step b') and an aqueous solution, said step being carried out at a temperature between 50 and 370°C; obtaining at least one gaseous effluent, an aqueous effluent and a hydrocarbon-based effluent, d) optionally fractionating all or part of the hydrocarbon-based effluent obtained from step c) to obtain at least one gaseous effluent, at least one fraction comprising compounds having a boiling point less than or equal to 175° C., and at least one hydrocarbon-based fraction comprising compounds having a boiling point greater than 175° C.

2. The method of claim 1 , further comprising step d).

3. The method according to claim 1 or 2, comprising step b').

4. The amount of hydrogen-containing gas stream fed to the reaction section of step a) is determined by the hydrogen coverage of the feedstock volume (m ３ ) Hydrogen 50-1000Nm ３ The method according to any one of claims 1 to 3, wherein

5. The amount of hydrogen-containing gas stream fed to the reaction section of step a) is determined by the hydrogen coverage of the feedstock volume (m ３ ) Hydrogen 200-300Nm ３ The method of claim 4, wherein

6. The process according to any one of claims 1 to 5, wherein the outlet temperature of step a) is at least 30°C higher than the inlet temperature of step a).

7. 7. The process according to claim 1, wherein at least a portion of the hydrocarbon-based effluent obtained from the separation step c) or at least a portion of the naphtha cut comprising compounds having a boiling point below 175° C. obtained from the fractionation step d) is sent to the hydrotreating step a) and / or to the hydrotreating step b).

8. 8. The process according to claim 1 , wherein at least a portion of the fraction comprising compounds having a boiling point above 175° C. obtained from fractionation step d) is sent to a hydrogenation step a) and / or a hydrotreating step b) and / or a hydrocracking step b').

9. 9. The method according to any one of claims 1 to 8, comprising a pretreatment step a0) of a feedstock comprising plastic pyrolysis oil, said pretreatment step a0) being carried out upstream of said hydrogenation step a) and comprising a filtration step and / or an electrostatic separation step and / or a washing step with an aqueous solution and / or an adsorption step.

10. 10. The process according to any one of the preceding claims, wherein the hydrocarbon-based effluent obtained from the separation step c) or at least one of the two liquid hydrocarbon-based streams obtained from step d) is fed, in whole or in part, to a steam cracking step e), which is carried out in at least one pyrolysis furnace at a temperature of between 700 and 900°C and at a pressure of between 0.05 and 0.3 MPa (relative).

11. The process according to any one of claims 1 to 10, wherein the reaction section of step a) employs at least two reactors operating in a sequence-variable mode.

12. The process according to any one of claims 1 to 11, wherein the stream containing the amine is injected upstream of step a).

13. 13. The method according to any one of claims 1 to 12, wherein the hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group containing either at least one Group VIII element and at least one Group VIB element, or at least one Group VIII element.

14. 14. The process according to any one of claims 1 to 13, wherein the hydrotreating catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay and mixtures thereof, and a hydrodehydrogenation functional group comprising at least one Group VIII element and / or at least one Group VIB element.

15. The process also includes a second hydrocracking step b''), which is carried out in a hydrocracking reaction section using at least one fixed bed, which contains n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrocracking catalyst, to which the fraction containing compounds having a boiling point above 175°C from step d) and a gas stream containing hydrogen are fed, the temperature in the hydrocracking reaction section being between 250 and 450°C, the partial pressure of hydrogen being between 1.5 and 20.0 MPa (absolute) and the hourly space velocity being between 0.1 and 10.0 h －１ and a hydrocracked effluent is obtained, which is sent to separation step c).

16. 16. The process according to any one of claims 1 to 15, wherein the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminum, amorphous silica-alumina and zeolites, and a hydrodehydrogenation functional group comprising at least one Group VIB metal selected from chromium, molybdenum and tungsten, either alone or in admixture, and / or at least one Group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

17. A product obtainable via the method according to any one of claims 1 to 16.

18. 18. A product according to claim 17, comprising, relative to the total weight of the product: - total content of metallic elements: less than or equal to 5.0 ppm by weight; - Content of iron element: 100 ppb by weight or less, - Silicon element content: 1.0 ppm by weight or less; - Sulfur content: 500 weight ppm or less, - Nitrogen content: 100 weight ppm or less, Chlorine content: 10 ppm by weight or less.

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