Method for treating plastic pyrolysis oil including H2S recycling process

Abstract

The present invention relates to a method for treating plastic pyrolysis oil, comprising the steps of: hydrotreating a feedstock in the presence of hydrogen and a catalyst; separating / washing the hydrotreated effluent in the presence of an aqueous solution; obtaining a first aqueous effluent and a hydrotreated hydrocarbon effluent; separating H2S contained in the first aqueous effluent; obtaining a gas phase containing H2S and a second aqueous effluent; the gas phase containing H2S can be at least partially recycled upstream of step b); separating NH3 contained in the second aqueous effluent; obtaining a gas phase containing NH3 and a third aqueous effluent. The present invention makes it possible to reduce the consumption of sulfurizing agents to maintain the catalyst in sulfide form in a low sulfur content feedstock by recycling the H2S resulting from the method.

Description

[Technical field]

[0001] The present invention relates to a method for treating plastic pyrolysis oil to obtain a hydrocarbon effluent that can be upgraded in a unit for storing fuels of petroleum, jet or gas oil or as a feedstock for a steam cracking unit. More particularly, the present invention relates to a method for the treatment of a feedstock resulting from the pyrolysis of plastic waste, which makes it possible to recycle the gas phase containing H2S resulting from the method, and which keeps the catalyst in the sulfide form in the catalytic stage of the method, thus reducing the consumption of added sulfiding agents. [Background technology]

[0002] The plastics obtained from the recovery and sorting channels can undergo a pyrolysis stage to obtain, among other things, pyrolysis oils. These plastic pyrolysis oils are generally incinerated to generate electricity and / or used as fuel for industrial or municipal heating boilers.

[0003] Another route for upgrading plastic pyrolysis oils is to use them as feedstock for steam cracking units to (re)create olefins, which are the constituent monomers of certain polymers. However, plastic waste is generally a mixture of several polymers, for example mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride or polystyrene. Furthermore, depending on the application, plastics may contain other compounds in addition to polymers, for example plasticizers, pigments, dyes or also residues of polymerization catalysts. Plastic waste may also contain small amounts of biomass, for example coming from household waste. The treatment of waste, especially storage, mechanical treatment, sorting or pyrolysis on the one hand, and also the storage and transport of pyrolysis oil on the other hand, can also cause corrosion. As a result, the oil resulting from the pyrolysis of plastic waste often contains a high content of many impurities, especially diolefins, metals, especially iron, silicon, or halogen compounds, especially chlorine-based compounds, heteroelements, such as sulfur, oxygen and nitrogen, and insoluble materials, which are not compatible with the steam cracking unit or units located downstream of the steam cracking unit, especially polymerization and selective hydrogenation processes. These impurities can cause problems of operability, especially problems of 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, characterized by the formation of gums. The gums and insoluble materials that may be present in the pyrolysis oil can cause clogging problems during processing.

[0004] Moreover, during the steam cracking stage, the yield of light olefins, especially ethylene and propylene, required by the petrochemical industry, strongly depends on the quality of the feedstock sent to the steam cracking. To characterize the hydrocarbon fractions, the BMCI (Bureau of Mines Correlation Index) is often used. This index was developed for the hydrocarbon products resulting from crude oil and is calculated from measurements of density and average boiling point: it is equal to 0 for normal paraffins and 100 for benzene. Its value therefore increases proportionately as the analyzed product has condensed aromatic structures, naphthenes having an intermediate BMCI value between paraffins and aromatics. Overall, a higher yield of light olefins occurs when the paraffin content increases and therefore the BMCI decreases. Conversely, a higher yield of undesirable heavy compounds and / or coke occurs when the BMCI increases.

[0005] In WO 2005 / 023363 a whole process for recycling plastic waste is provided, which is very general and relatively complex, and extends from the very stage of pyrolysis of plastic waste to a steam cracking stage. The process of WO 2005 / 023363 comprises, inter alia, a stage of hydrotreating the liquid phase resulting directly from the pyrolysis, preferably under very stringent conditions, in particular stringent with respect to temperature, for example at temperatures between 260°C and 300°C, a stage of separation of the hydrotreating effluent, and then a stage of hydrodealkylation of the separated heavy effluent, preferably at high temperatures, for example between 260°C and 400°C.

[0006] The unpublished patent application FR 21 / 00.026 describes a method for treating plastic pyrolysis oil with the aim of reducing and / or removing the impurities contained in the pyrolysis oil to obtain an effluent suitable for a steam cracker. The method comprises the following steps: a) hydrogenation of said feedstock in the presence of at least hydrogen and at least one hydrogenation catalyst at an average temperature between 140 and 340° C.; the outlet temperature of step a) is at least 15° C. higher than the inlet temperature of step a): obtaining a hydrogenated effluent; b) hydrotreating said hydrotreated 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 greater than the average temperature of step a); c) separation of the hydrotreated effluent in the presence of an aqueous stream at a temperature between 50 and 370° C.; obtaining at least a gaseous effluent, an aqueous liquid effluent and a hydrocarbon liquid effluent.

[0007] One route to remove the impurities contained in ex-plastics pyrolysis oils is therefore to carry out hydrotreating in the presence of a catalyst active in the form of sulfides.

[0008] In the context of feedstocks containing plastic pyrolysis oil, the available feedstocks are generally quite low in sulfur. In fact, a minimum pH2Sp is required in the hydroprocessing reactor in order to keep the catalysts in the sulfide form and therefore not reduce them. Taking into account the fact that the feedstock does not contain enough sulfur to maintain a sufficient pH2Sp in the reactor, a sulfiding agent, typically DMDS (dimethyl disulfide), is generally, and indeed necessarily, continuously added to the feedstock. The sulfiding agent decomposes very rapidly to H2S under the action of the temperature and hydrogen at the reactor inlet, thus providing the amount of H2S required to ensure a minimum and sufficient pH2Sp.

[0009] After hydrotreating, at least a part of the H2S contained in the effluent forms ammonium sulfide salts ((NH4)2S) with NH3 produced by hydrogenation of nitrogen compounds during hydrotreating. Unlike conventional feedstocks of fossil type, non-plastic pyrolysis oils generally contain a content of nitrogen greater than that of sulfur. These salts are generally removed by scrubbing with water followed by a (single) stage steam stripping of the aqueous effluent, which makes it possible to obtain a purified aqueous effluent and a gas phase containing H2S and NH3, which are generally discharged together at the top of a stripping tower. The gas phase containing H2S and NH3 is then generally incinerated to remove SO x (sulfur oxides) and N2 or NO x (nitrogen oxides) are formed.

[0010] The gas phase containing H2S and NH3 may be recovered and returned to the inlet of the hydrotreating unit to maintain the pH2Sp in the reactor without adding sulfiding agents. However, the NH3 contained in this gas phase prevents this from being done, since there is an enrichment of NH3 in the recycle loop which prevents the operation of the unit. Furthermore, the presence of NH3 reduces the pH2p. The gas phase containing H2S and NH3 therefore cannot be directly reused as a source of H2S to keep the catalyst in the sulfided form.

[0011] The present invention provides a process for the treatment of a feedstock containing plastic pyrolysis oil, which makes it possible to separate H2S and NH3, generally by stripping, in two stages, allowing the recycling of the phase containing only H2S to be used as a source of H2S at the inlet of the catalytic unit of the process, since the use of two stripping columns operating under different operating conditions makes it possible to separate H2S from NH3 and thus recover: a gas phase containing H2S, which can be recycled at the inlet of the hydroprocessing unit; and - A gas phase containing NH3; it can be incinerated or recycled to the inlet of the hydroprocessing unit.

[0012] The two-stage stripping, which makes it possible to separate H2S from NH3, therefore exhibits the following advantages: - removal of NH3 from the phase containing only H2S allows recycling of H2S at the inlet of the catalytic unit of the process; - High minimization of sulfurizing agent consumption; - Elimination of NH3 by incineration of the gas phase containing it results in the production of SO x It is easier because it no longer contains H2S, which forms a type of pollutant; - the gas phase containing NH3 can also be recycled at the inlet of the catalytic unit, advantageously in a stoichiometric amount suitable for the formation of salts during the separation / scrubbing stage c); -SO x better observation of environmental constraints; since most of the H2S is not incinerated (but, on the contrary, recycled in the loop); - Lower hydrogen consumption in the hydrotreating unit, as the sulfiding agent (DMDS) consumes hydrogen and decomposes; - Complete removal of NH3 in the gaseous effluent containing hydrogen and / or light hydrocarbons from the top of the separation / scrubbing section (step c) below), since NH3 was captured in the aqueous effluent in the form of ammonium sulfide by the recycled excess H2S. The gaseous effluent is thus free from NH3 and can therefore be sent to a steam cracker to increase the overall yield of olefins. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] International Publication No. 2018 / 055555 Summary of the Invention [Means for solving the problem]

[0014] (Summary of the invention) More specifically, the present invention relates to a method for the treatment of a feedstock containing plastic pyrolysis oil, comprising the steps of: a) an optional hydrogenation step carried out in a hydrogenation reaction section, using at least one fixed bed reactor having 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 containing hydrogen, said hydrogenation reaction section being used at an average temperature of 140-400° C., a hydrogen partial pressure of 1.0-10.0 MPa absolute, and an hourly space velocity of 0.1-10.0 h -1 obtaining a hydrogenated effluent; b) a hydrotreating step carried out in a hydrotreating reaction section containing at least one hydrotreating catalyst; said hydrotreating reaction section is fed at least with the feedstock or the hydrogenated effluent resulting from step a) and with a gas stream containing hydrogen, said hydrotreating reaction section being used at an average temperature of 250-430° C., a hydrogen partial pressure of 1.0-10.0 MPa absolute and an hourly space velocity of 0.1-10.0 h -1 obtaining a hydrotreated effluent; c) a separation step, which receives the hydrotreated effluent from step b) and, optionally, the hydrocracked effluent from step g) and an aqueous solution; obtaining at least a gaseous effluent, a first aqueous effluent and a hydrocarbon effluent, d) a step of separation of the H2S contained in the first aqueous effluent; obtaining a gas phase containing H2S and a second aqueous effluent; said gas phase containing H2S is optionally at least partially recycled upstream of step a) and / or step b) and / or step g), e) a step of separation of the NH3 contained in the second aqueous effluent; obtaining a gas phase containing NH3 and a third aqueous effluent; said gas phase containing NH3 is optionally at least partially recycled upstream of step a) and / or step b) and / or step g), f) optionally a step of fractionation of all or part of the hydrocarbon effluent resulting from step c) to obtain at least a gaseous effluent and at least a first hydrocarbon fraction comprising compounds having a boiling point less than or equal to 175° C. and a second hydrocarbon fraction comprising compounds having a boiling point greater than 175° C., g) an optional hydrocracking step carried out in a hydrocracking reaction section; using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, each containing at least one hydrocracking catalyst, said hydrocracking reaction section being fed with at least a portion of said hydrocarbon effluent resulting from step c) and / or at least a portion of the second hydrocarbon fraction resulting from step f) comprising compounds having a boiling point above 175° C., and a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450° C., with a hydrogen partial pressure between 1.5 and 20.0 absolute MPa, and with an hourly space velocity between 0.1 and 10.0 h . -1 a first hydrocracked effluent is obtained.

[0015] The invention therefore relates to a method that makes it possible to purify at least a portion of the impurities from the oil resulting from the pyrolysis of plastic waste, by hydrogenating it and therefore making it possible to upgrade it, in particular by incorporating it directly in a fuel storage unit or by adapting it to a treatment in a steam cracking unit, while the H2S resulting from the method can be recycled continuously to minimize the consumption of sulfurizing agents. The injection of sulfurizing agents remains necessary in particular at the beginning of the catalytic cycle, at the time when H2S is formed and separated in stage d) and recycled upstream of stages a) and / or b) and / or g) and / or upstream of the selective hydrogenation stage a0). Additional injections throughout the catalytic cycle may be necessary to compensate for natural losses. However, the fact that the invention allows the recycling of the gas phase containing H2S without NH3 makes it possible to significantly reduce the consumption of sulfurizing agents.

[0016] Another advantage consists in the removal of NH3 in the gaseous effluent containing hydrogen and / or light hydrocarbons from the top of the separation / scrubbing section (stage c)) by reaction with the recycled excess H2S in the form of ammonium sulfide in the aqueous effluent, in other words, NH3 remains in the aqueous effluent in the form of a salt.

[0017] 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 method is carried out, which risk is exacerbated by the often large amounts of diolefins, metals and halogen compounds present in plastic pyrolysis oils.

[0018] The method of the invention thus makes it possible to obtain a hydrocarbon effluent, which originates from the plastic pyrolysis oil and is at least partially free from the impurities of the starting plastic pyrolysis oil, thus limiting the operability problems, such as corrosion, coking or catalyst deactivation, that may be caused by these impurities, in particular in the steam cracking unit and / or in the units located downstream of the steam cracking unit, in particular in the polymerization and hydrogenation units. The removal of at least a portion of the impurities of the oil resulting from the pyrolysis of plastic waste also makes it possible to increase the scope of application of the target polymer, reducing its incompatibility of use.

[0019] According to an alternative embodiment, said gas phase containing H2S resulting from step d) is at least partially recycled upstream of step a) and / or step b) and / or step g).

[0020] According to an alternative embodiment, the process comprises a hydrogenation step a).

[0021] According to an alternative embodiment, the method comprises a fractionation step f).

[0022] According to an alternative embodiment, the process comprises a hydrocracking step g).

[0023] According to an alternative embodiment, stage d) of separation of the H2S contained in the first aqueous effluent is carried out by stripping said effluent with a stream containing water vapor, the pressure being between 0.5 and 1 MPa and the temperature being between 80 and 150°C.

[0024] According to an alternative embodiment, step e) of separation of the NH3 contained in the second aqueous effluent is carried out by stripping said effluent with a stream containing water vapor at a pressure of 0.1-0.5 MPa and a temperature of 80-150°C.

[0025] According to an alternative embodiment, the separation step c) comprises the following steps: c1) a separation step, to which the hydrotreated effluent resulting from step b) is fed; said step is carried out at a temperature between 200 and 450° C. and at a pressure substantially the same as that of step b); at least a gaseous effluent and a liquid effluent are obtained; optionally part of the liquid effluent is recycled upstream of step a) and / or step b), c2) a separation step, to which is fed the gaseous effluent resulting from step c1) and another part of the liquid effluent and the aqueous solution resulting from step c1), said step being carried out at a temperature between 20° C. and less than 200° C. and at a pressure substantially equal to or less than the pressure of step b), obtaining at least a gaseous effluent, a first aqueous effluent and a hydrocarbon effluent.

[0026] According to an alternative embodiment, the method comprises at least one stage a0) of pretreatment of a feedstock comprising plastic pyrolysis oil, optionally in admixture with a hydrocarbon effluent resulting from stage c), said pretreatment stage being carried out upstream of stage a) and / or upstream of stage b) and comprising a filtration stage and / or a centrifugation stage and / or an electrostatic separation stage and / or a stage of scrubbing with an aqueous solution and / or an adsorption stage and / or a selective hydrogenation stage.

[0027] According to an alternative embodiment, the hydrocarbon effluent resulting from the separation stage c) or at least one of the two liquid hydrocarbon fractions resulting from stage f) is fed completely or partly to a steam cracking stage h), which stage h) is carried out in at least one pyrolysis furnace, the temperature being between 700 and 900° C. and the pressure being between 0.05 and 0.3 relative MPa.

[0028] According to an alternative embodiment, said gas phase containing NH3 resulting from step e) is at least partially recycled upstream of step a) and / or step b) and / or step g).

[0029] According to an alternative embodiment, a stream containing nitrogen and / or sulfur compounds is injected upstream of stage a) and / or upstream of stage b).

[0030] According to an alternative form, 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 element from group VIII and at least one element from group VIB, or at least one element from group VIII.

[0031] According to an alternative embodiment, 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 element from group VIII and / or at least one element from group VIB.

[0032] According to an alternative embodiment, the method further comprises a second hydrocracking stage g'), which stage g') is carried out in a hydrocracking reaction section using at least one fixed bed reactor having 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 with at least a portion of the first hydrocracked effluent from the first hydrocracking stage g) and with a gas stream comprising hydrogen, said hydrocracking reaction section being used at a temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 MPa absolute and an hourly space velocity between 0.1 and 10.0 h -1 to obtain a second hydrocracked effluent.

[0033] According to an alternative form, the hydrocracking catalyst comprises a support selected from halogenated aluminas, combinations of oxides of boron and aluminium, amorphous silica-alumina and zeolites, and a hydrodehydrogenation functional group comprising at least one metal from group VIB selected from chromium, molybdenum and tungsten, either alone or in admixture, and / or at least one metal from group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0034] The present invention also relates to the products obtainable, preferably obtained, by the process according to the invention.

[0035] According to this alternative form, the product comprises, by total weight of the product: - Metal elements; the total content is less than or equal to 10.0 ppm by weight; - contains elemental iron: the content is less than or equal to 200 ppb by weight, and / or - elemental silicon; the content is less than or equal to 5.0 ppm by weight; and / or - sulfur; the content is less than or equal to 100 ppm by weight; and / or - nitrogen; the content is less than or equal to 100 ppm by weight; and / or - elemental chlorine; the content is less than or equal to 10 ppm by weight; and / or - Mercury; content is less than 5 ppb by weight.

[0036] According to the invention, pressure is absolute pressure, also indicated as abs (absolute) and is given in MPa (absolute) (MPa absolute) or MPa absolute (MPa abs.), unless stated otherwise.

[0037] According to the present invention, the expressions "of between A and B" and "between A and B" are synonymous and mean that both limits of the interval (A, B) are included in the stated range of values. If this is not the case and if both limits are not included in the stated range, such information will be made clear by the present invention.

[0038] Within the meaning of the present invention, ranges of various parameters for a given stage, such as pressure ranges and temperature ranges, can be used alone or in combination, for example, within the meaning of the present invention, a preferred pressure value range can be combined with a more preferred temperature value range.

[0039] Subsequently, specific and / or preferred embodiments of the present invention are described, which can be used separately or in combination together, without limitation, where the combination is technically feasible.

[0040] The groups of chemical elements are then 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 (or group VIIIB) according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification.

[0041] The metal content is measured by X-ray fluorescence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] (Detailed Description) (Feed material) According to the invention, "plastic pyrolysis oil" is an oil, advantageously in liquid form at ambient temperature, resulting from the pyrolysis of plastics, preferably plastic waste, especially originating from collection and sorting channels. It can also result from the pyrolysis of worn tires.

[0043] It especially comprises a mixture of hydrocarbon compounds, in particular paraffins, mono- and / or di-olefins, naphthenes and aromatic compounds. The boiling point of at least 80% by weight of these hydrocarbon compounds is preferably below 700° C., preferably below 550° C. In particular, depending on the origin of the pyrolysis oil, it may comprise 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 be 100% by weight of the hydrocarbon compounds.

[0044] 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.

[0045] The plastic pyrolysis oil may further contain, and usually does contain, impurities such as metals, especially iron, silicon or halogen compounds, especially chlorine compounds. These impurities may be present in the plastic pyrolysis oil in high contents, for example, up to 350 ppm by weight, or also up to 700 ppm by weight, actually even up to 1000 ppm by weight of halogen elements (especially chlorine) provided by halogen compounds, and up to 100 ppm by weight, actually even up to 200 ppm by weight of metal or metalloid elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals and metalloids can be placed in the same category as metallic contaminants, called metals or metal or metalloid elements. In particular, metals or metal or metalloid elements that may be contained in the oil resulting from the pyrolysis of plastic waste include silicon, iron or both. The plastic pyrolysis oil may also contain other impurities, such as heteroelements, particularly contributed by sulfur compounds, oxygen compounds and / or nitrogen compounds, generally in a content of less than 27,000 ppm by weight of heteroelements, preferably less than 15,500 ppm by weight of heteroelements. The sulfur compounds are generally present in a content of less than 2000 ppm by weight, preferably less than 500 ppm by weight. The oxygen compounds are generally present in a content of less than 15,000 ppm by weight, preferably less than 10,000 ppm by weight. The nitrogen compounds are generally present in a content of less than 10,000 ppm by weight, preferably less than 5000 ppm by weight. The plastic pyrolysis oil may also contain other impurities, such as heavy metals, such as mercury, arsenic, zinc and lead, such as mercury up to 100 ppb by weight or up to 200 ppb by weight.

[0046] The feedstock for the process according to the invention comprises at least one plastic pyrolysis oil. The feedstock may consist of one or more plastic pyrolysis oils. 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, suitably 70% to 100% by weight of plastic pyrolysis oil, based on the total weight of the feedstock.

[0047] The feedstock for the process according to the invention can include, in addition to one or more plastic pyrolysis oils, conventional petroleum feedstocks or feedstocks resulting from the conversion of biomass, which are then co-processed with the feedstock plastic pyrolysis oil.

[0048] The conventional petroleum feedstock may advantageously be a fraction or a mixture of fractions of the naphtha, gas oil or vacuum gas oil type.

[0049] The feedstock resulting from the conversion of biomass can advantageously be chosen from vegetable oils, oils from algae or algae oils, fish oils, waste edible oils, and fats of vegetable or animal origin, or mixtures of such feedstocks. The vegetable oils can advantageously be completely or partially crude or refined, and can be obtained from plants chosen from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor oil plants, cotton plants, peanut oil, linseed oil and sea kale oil, as well as all oils obtained, for example, from sunflower or rapeseed by genetic modification or hybridization, although this list is not limiting. The animal fats are advantageously chosen from blubber and fats, and consist of residues from the food industry or originate from the catering industry. Frying oils, various animal oils, such as fish oil, tallow or lard, can also be used. The feedstock resulting from the conversion of biomass can also advantageously be chosen from methyl esters of fatty acids of vegetable and / or animal origin, or from methyl esters of fatty acids of waste edible vegetable oils.

[0050] The feedstock resulting from the conversion of biomass can also be selected from feedstocks originating from processes for thermal or catalytic conversion of biomass, such as oils originating from biomass, especially lignocellulosic biomass, by various liquefaction processes, such as 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 or their by-products. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and aromatic polymers (lignin).

[0051] The feedstock resulting from the conversion of biomass can also advantageously be chosen from feedstocks resulting from the paper industry.

[0052] Plastic pyrolysis oils result from thermal or catalytic pyrolysis processes or can also be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0053] (Preprocessing (optional)) Said feedstock comprising plastic pyrolysis oil can advantageously be pretreated in at least one optional pretreatment stage a0) before the hydrogenation stage a) and / or the hydrotreating stage b), possibly in admixture with the hydrocarbon effluent from stage c), to obtain a pretreated feedstock, which is fed to stage a) and / or stage b).

[0054] According to an alternative embodiment, this optional pretreatment step a0) makes it possible to reduce the amount of contaminants and solid particles that may be present in the feedstock containing plastic pyrolysis oil, in particular the amount of iron and / or silicon and / or chlorine. This optional step a0) in particular makes it possible to remove sediments that may be formed as a result of the unstable nature of the pyrolysis oil and / or compatibility problems between two different feedstocks. Therefore, the optional step a0) of pretreatment of the feedstock containing plastic pyrolysis oil is advantageously carried out in particular when said 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 and / or solid particles, and in particular when said feedstock contains more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, in fact even more than 20 ppm by weight of silicon. Likewise, the optional pretreatment step a0) of the feedstock comprising plastic pyrolysis oil is advantageously carried out, in particular when said feedstock comprises more than 10 ppm by weight, in particular more than 20 ppm by weight and more particularly more than 50 ppm by weight of chlorine.

[0055] Said optional pretreatment step a0) can be carried out by any method known to the person skilled in the art making it possible to reduce the amount of contaminants, which may in particular comprise a filtration step and / or a centrifugation step and / or an electrostatic separation step and / or a step of scrubbing with an aqueous solution and / or an adsorption step and / or a selective hydrogenation step.

[0056] If the optional pretreatment stage a0) comprises a filtration stage and / or a centrifugation stage and / or an electrostatic separation stage and / or an aqueous scrubbing stage and / or an adsorption stage, it is advantageously carried out at a temperature between 20 and 400° C., preferably between 40 and 350° C., and at a pressure between 0.15 and 10.0 MPa absolute, preferably between 0.2 and 7.0 MPa absolute.

[0057] According to an alternative embodiment, the optional pretreatment stage a0) is carried out in an adsorption section operated in the presence of at least one adsorbent, preferably of the alumina type, the specific surface area of ​​which is less than 100 m 2 / g or more, preferably 200m 2 The specific surface area of ​​said at least one adsorbent is advantageously 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).

[0058] Advantageously, said adsorbent contains less than 1% by weight of metal elements, preferably no metal elements. The term "metal elements of the adsorbent" should be understood to mean elements of columns 6 to 10 of the Periodic Table of the Elements (new IUPAC classification). The residence time of the feedstock in the adsorption section is generally between 1 and 180 minutes.

[0059] 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, containing the adsorbent. If the adsorption section comprises two adsorption columns, one operation mode can be a "swing" operation, where one of the columns is on-line, i.e. in operation, while the other column is in reserve. When the adsorbent of the on-line column is consumed, this column is isolated, while the in-reserve column is placed on-line, i.e. in operation. The used adsorbent can then be regenerated in situ and / or replaced with fresh adsorbent, so that the column containing it can be brought back on-line again, where the other column is isolated.

[0060] Another mode of operation is to have at least two columns operated in series. When the adsorbent of the first column is consumed, this first column is isolated and the spent adsorbent is either regenerated in situ or replaced with fresh adsorbent. The column is then brought back online in the last position, and so on. This operation is also known as the permutable mode, or according to the term PRS for Permutable Reactor System, or "lead-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 and insoluble materials resulting from diolefins 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 advantageously facilitates replacement and / or regeneration of the adsorbent without shutting down the pretreatment unit, and indeed even without shutting down the process, thus reducing the risk of clogging and thus making it possible to avoid shutting down the unit due to clogging, control costs and limit adsorbent consumption.

[0061] According to another alternative form, said optional pretreatment stage a0) is carried out in a section for scrubbing with an aqueous solution, for example water or an acidic or basic solution. This scrubbing section can contain equipment that allows the feedstock to be contacted with an aqueous solution and for the phase separation to obtain, on the one hand, the pretreated feedstock and, on the other hand, an aqueous solution containing impurities. These equipment can for example comprise stirred reactors, decanters, mixer-decanters and / or cocurrent or countercurrent scrubbing columns.

[0062] According to another alternative, the optional pretreatment step a0) is carried out by filtration. The filtration step makes it possible to remove inorganic solids, sediments and / or fines contained in the feedstock, in particular metals, metal oxides and metal chlorides. Use is generally made of filters whose pores have a size (for example diameter or equivalent diameter) of less than 25 μm, preferably less than or equal to 10 μm and even more preferably less than or equal to 5 μm. According to another alternative, use may be made of filters whose pores have a size of less than 25 μm but more than 5 μm. Use may be made of a series of filters with different pore sizes, in particular with a series of filters with a pore size that decreases in the direction of flow of the feedstock. These filtration media are well known for industrial applications. For example, cartridge filters or self-cleaning filters are suitable. The solids content can be measured, for example, by the heptane insolubles test, ASTM D-3279 method. The content of insolubles in heptane must be reduced to less than 0.5% by weight, preferably less than 0.1% by weight.

[0063] According to a particular embodiment, stage a0) of pretreatment by filtration comprises at least one filter, the pore size of which is less than 10 μm and preferably greater than 5 μm, followed by a filtration system, the pore size of which is less than 2 μm, preferably less than 1 μm.

[0064] According to another particular embodiment, the stage a0) of pretreatment by filtration comprises at least one filter, the pore size of which is less than 10 μm and preferably greater than 5 μm, followed by an electrostatic precipitation system.

[0065] According to another particular embodiment, stage a0) of pretreatment by filtration comprises at least one filter, the pore size of which is less than 10 μm and preferably greater than 5 μm, followed by a system of one or more filters using a filter aid, for example sand or diatomaceous earth.

[0066] According to another alternative embodiment, said optional pretreatment step a0) is carried out by centrifugation. According to another alternative embodiment, the pretreatment step a0) comprises centrifugation and filtration.

[0067] According to another alternative form, said optional pretreatment stage a0) comprises a selective hydrogenation stage, which is advantageously carried out in a reaction section fed with said feedstock, optionally pretreated by one or more of the above-mentioned pretreatments, and with a gas stream containing hydrogen, in the presence of at least one selective hydrogenation catalyst, at a temperature between 100 and 280° C., a hydrogen partial pressure between 1.0 and 10.0 MPa absolute and an hourly space velocity between 0.3 and 10.0 h . -1 and obtaining a hydrogenated effluent.

[0068] This selective hydrogenation step is carried out with just the amount of soluble hydrogen necessary for the selective hydrogenation of the diolefins present in the pyrolysis oil, under conditions of hydrogen pressure and temperature that allow the feedstock to be maintained in the liquid phase. It is advantageously carried out under milder conditions than the hydrogenation step a). The selective hydrogenation of diolefins in the liquid phase thus makes it possible to avoid or at least limit the formation of "gums", i.e. the polymerization of diolefins and therefore the formation of oligomers and polymers that may clog one or more downstream reaction sections. Styrene compounds, especially styrene, which may be present in the feedstock, can also behave similarly to diolefins with respect to the formation of gums, due to the fact that the double bond of the vinyl group is conjugated with the aromatic nucleus. The selective hydrogenation step makes it possible to obtain a selectively hydrogenated effluent, i.e. an effluent with a reduced content of olefins, especially diolefins and possibly styrene compounds.

[0069] The reaction section employs selective hydrogenation, preferably in a fixed bed, in the presence of at least one selective hydrogenation catalyst, in which the average temperature (or WABT as defined below for hydrogenation stage a) is advantageously between 100 and 280°C, preferably between 120 and 260°C, suitably between 130 and 250°C, the hydrogen partial pressure is between 1.0 and 10.0 MPa absolute, preferably between 2.0 and 8.0 MPa absolute, and the hourly space velocity (HSV) is between 0.3 and 10.0 h -1 , preferably 0.5 to 5.0 h -1 It is.

[0070] The amount of gas stream containing hydrogen (H2) fed to said reaction section of the selective hydrogenation stage is advantageously determined by the hydrogen coverage of the volume (m 3 ) Hydrogen 1-200Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 1~50Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 5~20Sm 3 (Sm 3 / m 3 ) is ensured.

[0071] The hourly space velocity (HSV) and hydrogen coverage are as defined below for the hydrogenation stage a).

[0072] The selective hydrogenation step is preferably carried out in a fixed bed. It can also be carried out in an ebullated or moving bed.

[0073] Advantageously, the reaction section of the selective hydrogenation stage comprises from 1 to 5 reactors. According to a particular embodiment of the invention, the reaction section comprises from 2 to 5 reactors, which are operated in a variable-sequence mode, also known as PRS or "lead-lag" for Permutable Reactor System as described in hydrogenation stage a). According to a particularly preferred alternative, the selective hydrogenation reaction section comprises 2 reactors operated in a variable-sequence mode.

[0074] Said selective hydrogenation catalyst is generally a catalyst as described in hydrogenation step a). It can be the same as or different from the catalyst of hydrogenation step a).

[0075] The content of impurities, particularly diolefins, of the hydrogenated effluent obtained on conclusion of the selective hydrogenation step is reduced with respect to the content of the same impurities, particularly diolefins, contained in the feed of the process. The selective hydrogenation step generally makes it possible to convert at least 20%, preferably at least 30%, of the diolefins contained in the initial feed.

[0076] Advantageously, said optional pretreatment step a0) comprises a filtration step and / or a centrifugation step and / or an electrostatic separation step and / or a step of scrubbing with an aqueous solution and / or an adsorption step, followed by a selective hydrogenation step.

[0077] Said optional pretreatment step a0) can optionally also be fed with at least a portion of the hydrocarbon effluent resulting from step c) of the process and / or a portion of the first hydrocarbon fraction resulting from step f) comprising compounds with a boiling point below 175° C. and / or a portion of the second hydrocarbon fraction resulting from step f) comprising compounds with a boiling point above 175° C., either in a mixture with the feedstock comprising plastic pyrolysis oil or separately. Recycling at least a portion of the liquid effluent resulting from step c) and / or at least a portion of the one or more hydrocarbon effluents resulting from step f) makes it possible in particular to increase the settling and therefore improve the pretreatment of the feedstock, after optional filtration.

[0078] Said optional pretreatment stage a0) therefore makes it possible to obtain a pretreated feedstock which is then fed to stage b) and / or to the hydrogenation stage a), if present.

[0079] (Hydrogenation step a) (optional) According to the invention, the process optionally comprises a hydrogenation step a) carried out in a hydrogenation reaction section, using at least one fixed bed reactor having n catalyst beds, n being an integer greater than or equal to 1, each containing at least one hydrogenation catalyst, said hydrogenation reaction section being fed at least with said feedstock, optionally pretreated said feedstock, and a gas stream comprising hydrogen, said hydrogenation reaction section being used at an average temperature of 140-400° C., a hydrogen partial pressure of 1.0-10.0 MPa absolute, and an hourly space velocity of 0.1-10.0 h -1 and obtaining a hydrogenated effluent.

[0080] Stage a) is carried out under conditions of temperature and hydrogen pressure that allow in particular the hydrogenation of diolefins that may remain after the optional selective hydrogenation stage, and of olefins at the beginning of the hydrogenation reaction section, while increasing the temperature profile allows hydrodemetallization and hydrodechlorination to be carried out, in particular at the end of the hydrogenation reaction section. The necessary amount of hydrogen is injected to allow at least partial hydrogenation of the diolefins and olefins present in the plastic pyrolysis oil, at least partial hydrodemetallization of the metals, in particular the retention of silicon, and at least partial conversion of chlorine (to give HCl). The hydrogenation of the diolefins and olefins therefore makes it possible to avoid or at least limit the formation of "gums", i.e. the polymerization of the diolefins and olefins, and therefore the formation of oligomers and polymers that may clog the reaction section of the hydrotreating stage b). In parallel with the hydrogenation, the hydrodemetallization, in particular the retention of silicon during stage a), makes it possible to limit the catalyst deactivation in the reaction section of the hydrotreating stage b). Furthermore, the conditions of step a) make it possible to convert at least a portion of the chlorine.

[0081] The control of temperature is important in this stage and must satisfy competing constraints. On the one hand, the inlet temperature and the temperature throughout the hydrogenation reaction section must be high enough to allow the hydrogenation of diolefins and olefins at the beginning of the hydrogenation reaction section. On the other hand, the inlet temperature of the hydrogenation reaction section must be low enough to avoid deactivation of the catalyst. Since the hydrogenation reactions, especially for the hydrogenation 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. Therefore, the outlet temperature of the reaction section of stage a) is generally at least 3° C., preferably at least 5° C., higher than the inlet temperature of the reaction section of stage a).

[0082] The temperature in step a), whether this is the average temperature (WABT), the inlet temperature of the reaction section or the increase in temperature in step a) between the inlet and the outlet of the reaction section, can in particular be controlled by the injection of a diluent in step a), preferably by recycling a portion of the liquid effluent resulting from step c) and / or by recycling at least a portion of one or more hydrocarbon effluents resulting from step f), in particular by the recycle ratio and / or the temperature of the recycled effluent.

[0083] The temperature difference between the inlet and the outlet of the reaction section of stage a) is adapted to the injection of a gaseous (hydrogen) or liquid cooling stream, in particular a portion of the liquid hydrocarbon effluent resulting from stage c).

[0084] The temperature difference between the inlet and the outlet of the reaction section in step a) is solely due to the exothermic nature of the chemical reaction taking place in the reaction section and therefore does not involve the use of heating means (oven, heat exchanger, etc.).

[0085] The inlet temperature of the reaction section in step a) is between 135 and 397°C, preferably between 240 and 347°C.

[0086] The outlet temperature of the reaction section of step a) is between 138 and 400°C, preferably between 243 and 350°C.

[0087] According to the invention, it is advantageous to carry out the hydrogenation of the diolefins and part of the hydrodemetallization reaction in one and the same stage, at a temperature sufficient to limit the deactivation of the catalyst in stage a), which is manifested by a decrease in the conversion of the diolefins. This same stage also makes it possible to benefit from the heat from the hydrogenation reactions, in particular the reactions for the hydrogenation of part of the olefins and diolefins, and to increase the temperature profile in this stage, thus eliminating the need for a heating device between the catalytic hydrogenation section and the catalytic hydrotreating section.

[0088] The reaction section carries out hydrogenation in the presence of at least one hydrogenation catalyst, the average temperature (or WABT as defined below) being advantageously between 140 and 400°C, preferably between 240 and 350°C, particularly preferably between 260 and 330°C, the hydrogen partial pressure being between 1.0 and 10.0 MPa absolute, preferably between 1.5 and 8.0 MPa absolute, and the hourly space velocity (HSV) being between 0.1 and 10.0 h -1 , preferably 0.2 to 5.0 h -1 , highly preferably 0.3~3.0h -1 It is.

[0089] According to the invention, the "average temperature" of the reaction section corresponds to the weight-average bed temperature (WABT), which is well known to the person skilled in the art. The average temperature is advantageously determined depending on the catalyst system used, the equipment and their configuration. The average temperature (or WABT) is calculated in the following way:

[0090]

number

[0091] Hourly space velocity (HSV) is defined herein as the ratio of the hourly volumetric flow rate of the feedstock, optionally including pretreated plastic pyrolysis oil, to the volume of the catalyst.

[0092] The hydrogen coverage is the volumetric flow rate of hydrogen obtained under standard temperature and pressure conditions, calculated at 15°C (volume (m 2 ) of the feedstock) without taking into account the "fresh" feedstock, i.e. without taking into account the recycled fraction, in particular the recycled liquid effluent resulting from step c) and / or the liquid effluent resulting from step f). 3 ) per m of H2 standard 3 (Sm 3is defined as the ratio of the volumetric flow rate of the feedstock to be treated, possibly pretreated, to the volumetric flow rate of the feedstock to be treated.

[0093] The amount of gas stream containing hydrogen (H2) fed to said reaction section in step a) is advantageously determined by the hydrogen coverage of the volume (m 3 ) Hydrogen 100~1500Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 200~1000Sm 3 (Sm 3 / m 3 ), preferably the volume of the feedstock (m 3 ) Hydrogen 250~800Sm 3 (Sm 3 / m 3 ) is set to be.

[0094] Hydrogen can be obtained from fossil sources or from renewable sources, for example from the gasification of plastic waste, or can be produced by electrolysis.

[0095] 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 lies in an optimized processing of the feedstock while reducing the risk of clogging of one or more catalyst beds and thus making it possible to avoid unit shutdowns due to clogging.

[0096] According to a preferred alternative, these reactors are operated in a permutable mode, known as PRS (Permutable Reactor System), or "lead-lag". The combination of at least two reactors in PRS mode makes it possible to isolate the reactor, drain the spent catalyst, recharge the reactor with fresh catalyst and put said reactor back into operation without shutting down the process. The PRS technology is particularly described in patent FR 2 681 871.

[0097] According to a particularly preferred alternative, the hydrogenation reaction section of step a) comprises two reactors operated in a sequence-variable mode.

[0098] Advantageously, reactor internals, for example of the filter plate type, can be used to prevent clogging of the reactor or reactors. Examples of filter plates are described in patent FR 3 051 375.

[0099] Advantageously, said hydrogenation catalyst comprises a support, preferably an inorganic support, and a hydrodehydrogenation functional group.

[0100] According to an alternative form, the hydrodehydrogenation functional group especially comprises at least one element from group VIII and at least one element from group VIB. The at least one element from group VIII is preferably selected from nickel and cobalt, and the at least one element from group VIB is preferably selected from molybdenum and tungsten. According to this alternative form, the total content of metal elements from groups VIB and VIII, expressed as oxide, 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.

[0101] The weight ratio of the metal(s) from group VIB to the metal(s) from group VIII, expressed as metal oxides, is preferably 1-20, suitably 2-10.

[0102] According to this alternative form, the reaction section of step a) for example comprises a hydrogenation catalyst comprising 0.5% to 12% by weight of nickel, preferably 0.9% 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), preferably on an inorganic support, preferably an alumina support.

[0103] According to another alternative form, the hydrodehydrogenation functional group comprises, preferably consists of, at least one element from group VIII, preferably nickel. According to this alternative form, 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 reduced form, preferably on an inorganic support, preferably on an alumina support.

[0104] The support of 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, possibly 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 B2O3 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.

[0105] The hydrogenation catalyst is, for example, in the form of an extrudate.

[0106] Highly preferably, step a) can use, in addition to the one or more hydrogenation catalysts described above, at least one hydrogenation catalyst used in step a) containing less than 1% by weight of nickel, expressed as nickel oxide NiO, and at least 0.1% by weight of nickel, preferably 0.5% by weight of nickel, expressed as molybdenum oxide MoO3, and at least 0.1% by weight of molybdenum, preferably 0.5% by weight of molybdenum, on an alumina support. This catalyst is not highly metal-free and can preferably be placed upstream or downstream, preferably upstream, of the one or more hydrogenation catalysts described above.

[0107] Preferably, step a) can use at least one guard bed upstream of the hydrogenation catalyst or catalysts, containing an adsorbent of the alumina, silica-alumina, zeolite and / or activated carbon type, optionally containing a metal from group VIB and / or group VIII. Use may also be made of a series of guard beds with particles of different sizes, in particular with sizes decreasing (also called "grading") in the direction of flow of the feedstock.

[0108] Said hydrogenation step a) makes it possible to obtain a hydrogenated effluent, i.e. an effluent with a reduced content of olefins, in particular diolefins, and metals, in particular silicon. The content of impurities, in particular diolefins, of the hydrogenated effluent obtained at the end of step a) is reduced relative to the content of the same impurities, in particular diolefins, contained in the feed of the process. Hydrogenation step a) generally makes it possible to convert at least 40%, preferably at least 60%, of the diolefins and also at least 40%, preferably at least 60%, of the olefins contained in the initial feed. The heat released by the saturation of the double bonds makes it possible to increase the temperature of the reaction medium and to initiate the hydrotreating reaction, in particular the at least partial removal of other pollutants, such as silicon and chlorine. Preferably, at least 50%, more preferentially at least 75%, of the chlorine and silicon of the initial feed are removed during step a). The hydrogenated effluent obtained at the end of hydrogenation step a) is preferably sent directly to hydrotreating step b).

[0109] (hydrotreatment stage b)) According to the invention, the process comprises a hydrotreating step b), which is carried out in a hydrotreating reaction section containing at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with a feedstock, optionally pretreated in step a0), or with the hydrotreated effluent resulting from step a), and with a gas stream containing hydrogen, said hydrotreating reaction section being used at an average temperature between 250 and 430° C., with a hydrogen partial pressure between 1.0 and 10.0 MPa absolute, and with an hourly space velocity between 0.1 and 10.0 h -1 to obtain a hydrotreated effluent.

[0110] Advantageously, step b) carries out hydrotreating reactions well known to those skilled in the art, more particularly hydrotreating reactions such as the hydrogenation of aromatic compounds, hydrodesulfurization and hydrodenitrification, followed by the hydrogenation of olefins and residual halogen compounds, and hydrodemetallization.

[0111] The hydrotreating reaction section is advantageously operated at a pressure equivalent to that used in the reaction section of the hydrotreating stage a) and at an average temperature generally higher than the average temperature of the reaction section of the hydrotreating stage a). The hydrotreating reaction section is therefore advantageously operated at an average hydrotreating temperature of 250-430° C., preferably 280-380° C., with a hydrogen partial pressure of 1.0-10.0 MPa absolute and with 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 hour -1 The hydrogen coverage in step b) is advantageously determined by the volume (m ) of fresh feedstock. 3 ) Hydrogen 100~1500Sm 3 , preferably fresh feedstock volume (m 3 ) Hydrogen 200~1000Sm 3 , preferably fresh feedstock volume (m 3 ) Hydrogen 250~800Sm 3 The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those given above.

[0112] The hydrotreating step is preferably carried out in a fixed bed. It can also be carried out in an ebullated, entrained or moving bed. If the hydrotreating step is carried out in an ebullated, entrained or moving bed, an additional step of hydrotreating in a fixed bed can be carried out under the same range of operating conditions after the hydrotreating in the ebullated, entrained or moving bed, with or without intermediate separation of the gas stream.

[0113] Preferably, the process comprises a hydrotreating step b) which is carried out in a hydrotreating reaction section using at least one fixed bed reactor having n catalyst beds, n being an integer equal to or greater than 1, each containing at least one hydrotreating catalyst.

[0114] Said hydrotreating reaction section is advantageously fed with the feedstock or said hydrogenated effluent from step a) and a gas stream containing hydrogen at least at the first catalyst bed of the first reactor in operation. Injection of at least a portion of the feedstock or the hydrogenated effluent from step a) and / or at least a portion of the hydrogen between the different catalyst beds is also possible. Optionally, said reaction section of step b) can also be fed with at least a portion of the liquid effluent from step c) and / or at least a portion of one of the effluents from step f).

[0115] Advantageously, said step b) is carried out in a hydrotreating reaction section comprising at least one, preferably 1 to 5, fixed bed reactors having n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, suitably between 2 and 5, said bed or beds each comprising at least one and preferably not more than 10 hydrotreating catalysts. When a reactor comprises several catalyst beds, i.e. at least 2, preferably between 2 and 10, suitably between 2 and 5, said catalyst beds are preferably arranged in series within said reactor.

[0116] If step b) is carried out in a hydrotreating reaction section containing 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-lag) mode and swing mode, are well known to the person skilled in the art and are advantageously defined above.

[0117] In another embodiment of the invention, the hydrotreating reaction section comprises a single fixed bed reactor containing n catalyst beds, n being an integer equal to or greater than 1, preferably between 1 and 10, preferably between 2 and 5.

[0118] In a particularly preferred embodiment, the hydrogenation reaction section of stage a) comprises two reactors operating in variable sequence mode and is followed by a hydrotreating reaction section of stage b), which comprises a single fixed bed reactor.

[0119] Advantageously, the hydrotreating catalyst used in step b) can be selected from known hydrodemetallization, hydrotreating or silicon Scabbins catalysts, and combinations thereof, which are in particular used for the treatment of petroleum fractions. Known hydrodemetallization catalysts are, for example, those described in patents EP 0 113 297, EP 0 113 284, US 5 221 656, US 5 827 421, US 7 119 045, US 5 622 616 and US 5 089 463. Known hydrotreating catalysts are, for example, those described in patents EP 0 113 297, EP 0 113 284, US 6 589 908, US 4 818 743 or US 6 332 976. Known silicon scavenging catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0120] In particular, said hydrotreating catalyst comprises a support, preferably an inorganic support, and at least one metal element carrying hydrodehydrogenation functional groups. Said metal element carrying hydrodehydrogenation functional groups advantageously comprises at least one element from group VIII and / or at least one element from group VIB, the at least one element from group VIII being preferably selected from the group consisting of nickel and cobalt, and the at least one element from group VIB being preferably selected from the group consisting of molybdenum and tungsten. The total content of metal elements from groups VIB and VIII, expressed as oxide, 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 and WO3, respectively. The weight ratio of the metal or metals from group VIB to the metal or metals from group VIII, expressed as metal oxides, is preferably between 1.0 and 20, suitably between 2.0 and 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, preferably 1% to 8% by weight of nickel (expressed as nickel oxide NiO), relative to the total weight of the hydrotreating catalyst, 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 an inorganic support, preferably an alumina support.

[0121] The support of the hydrotreating catalyst is advantageously chosen from alumina, silica, silica-alumina, magnesia, clay and mixtures thereof. The support may further comprise a dopant compound, in particular boron oxide, in particular boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and an oxide chosen from mixtures of these oxides. Preferably, the hydrotreating catalyst comprises an alumina support, preferably an alumina support 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 B2O3 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.

[0122] The hydrotreating catalyst may, for example, be in the form of an extrudate.

[0123] 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 makes it possible to further improve the removal of pollutants, in particular metals, such as silicon.

[0124] According to another aspect of the invention, the hydrotreating catalyst further 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 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 compounds containing a furan ring or sugars.

[0125] Suitably, step b) may employ at least one guard bed or a series of guard beds of the "staged" type, as described above for step a), upstream of the hydrogenation catalyst or catalysts.

[0126] Advantageously, the hydrotreating step b) allows the hydrogenation of at least 80%, preferably all, of the olefins remaining after the hydrotreating step a), but also allows at least 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 outlet of step b) is less than 100 ppm by weight.Preferably, the sulfur content at the outlet of step b) is less than 100 ppm by weight.Step b) can also allow the content of contaminants, such as the content of metals, in particular the silicon content, to be further reduced.Preferably, the content of metals at the outlet 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.

[0127] Depending on the content of sulfur compounds in the initial feedstock to be treated, a stream containing a sulfiding agent can be injected in the optional pretreatment stage a0), upstream of the optional hydrogenation stage a) and / or hydrotreating stage b) and / or upstream of one of the optional hydrocracking stages g) (if they are present), preferably upstream of the hydrogenation stage a) and / or hydrotreating stage b), to ensure a sufficient amount of sulfur to form the active entities of the catalyst (in the form of sulfides).

[0128] This activation or sulfurization step is carried out by methods well known to those skilled in the art, advantageously under a sulfo-reducing atmosphere in the presence of hydrogen and hydrogen sulfide. The sulfurization agent is preferably a hydrocarbon fraction with a boiling point below 400° C. containing H2S gas, elemental sulfur, CS2, thiols, sulfides and / or polysulfides, sulfur compounds used for the activation of the hydrocarbon feedstock with a view to sulfurizing the catalyst or any other sulfur-containing compound. Said sulfur-containing compound is advantageously selected from alkyl disulfides, such as dimethyl disulfide (DMDS), alkyl sulfides, such as dimethyl sulfide, thiols, such as n-butyl thiol (or 1-butane thiol), and polysulfide compounds of the tert-nonyl polysulfide type. The catalyst can also be sulfurized by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfurized in situ in the presence of the sulfurization agent and the hydrocarbon feedstock. Highly preferably, the catalyst is sulfided in situ in the presence of a feedstock doped with dimethyl disulfide.

[0129] The injection of the sulfurizing agent is particularly necessary at the beginning of the catalytic cycle, when H2S is formed and separated in step d) and recycled upstream of steps a) and / or b) and / or g) or upstream of the selective hydrogenation step of the pretreatment a0). Additional injections throughout the catalytic cycle may be necessary to compensate for natural losses. However, the fact that the invention allows the recycling of the gas phase containing H2S without NH3 makes it possible to significantly reduce the consumption of sulfurizing agent.

[0130] (separation step c)) According to the invention, the treatment method comprises a separation step c), advantageously carried out in at least one scrubbing / separation section, fed with at least the hydrotreated effluent resulting from step b), the hydrocracked effluent resulting from optional steps g) and g') and an aqueous solution, to obtain at least a gaseous effluent, a first aqueous effluent and a hydrocarbon effluent.

[0131] 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 can be at least partially recycled to the hydrogenation step a) and / or to the hydrotreating step b) and / or to the hydrocracking step g), the recycling system being capable of comprising a purification section.

[0132] The gaseous effluent may also form the subject of one or more additional separations for the purpose of recovering at least one hydrogen-rich gas and / or light hydrocarbons, in particular ethane, propane and butane, which may advantageously be sent separately or as a mixture to one or more furnaces of steam cracking stage h) in order to increase the overall yield of olefins.

[0133] The hydrocarbon effluent resulting from the separation stage c) is sent, partially or completely, either directly to the inlet of the steam cracking unit or to an optional fractionation stage f). Preferably, the liquid hydrocarbon effluent is sent, partially or completely, to the fractionation stage f).

[0134] The first aqueous effluent obtained at the end of step c) advantageously contains ammonium salts and / or hydrochloric acid, and also dissolved H2S and NH3.

[0135] This separation step c) in particular makes it possible to remove ammonium chloride salts, thus limiting the risk of clogging, in particular in the transfer lines and / or in the sections of the method of the invention and / or in the transfer lines to the steam cracker, by precipitation of ammonium chloride salts. The ammonium chloride salts are formed by reaction between chloride ions and ammonium ions. The chloride ions are released in the form of HCl by hydrogenation of the chlorine compounds, in particular during steps a) and b), and subsequently dissolve in water. The ammonium ions are generated in the form of NH3 by hydrogenation of the nitrogen compounds, in particular during step b), and / or are provided by injection of amines, and subsequently dissolve in water. It also makes it possible to remove hydrochloric acid formed by reaction of hydrogen ions with chloride ions. This step c) also makes it possible to remove ammonium sulfide salts ((NH4)2S), formed by reaction between H2S and NH3 resulting from hydrodesulfurization of the sulfur compounds.

[0136] Depending on the content of chlorine compounds in the initial feedstock to be treated, a stream containing nitrogen compounds, for example amines, such as monoethanolamine, diethanolamine and / or monodiethanolamine, can be injected upstream of the pretreatment selective hydrogenation stage a0) and / or upstream of the hydrogenation stage a) and / or between the hydrogenation stage a) and the hydrotreating stage b) and / or between the hydrocracking stage g) and the separation stage c), preferably upstream of the hydrogenation stage a), to ensure a sufficient amount of ammonium ions to combine with the chloride ions formed during the hydrotreating stage, thus making it possible to limit the formation of hydrochloric acid and therefore the corrosion downstream of the separation section.

[0137] According to an alternative embodiment, the gas phase containing NH3 resulting from step e) can also be used as nitrogen compound.

[0138] Advantageously, separation step c) comprises the injection of an aqueous solution, preferably water, into the hydrotreated effluent resulting from step b) or the hydrocracked effluent resulting from optional step g), upstream of the scrubbing / separation section, to at least partially dissolve the ammonium chloride salts and / or hydrochloric acid, thus improving the removal of chlorinated impurities and reducing the risk of clogging due to accumulation of ammonium chloride salts.

[0139] The temperature at which separation step c) is advantageously carried out is between 20 and 450° C., preferentially between 100 and 440° C., preferably between 200 and 420° C. It is important to operate in this temperature range (and therefore not to cool the hydrotreated effluent too much) at the risk of line clogging due to precipitation of ammonium chloride salts. Advantageously, the pressure at which separation step c) is carried out is close to the pressure used in steps a) and / or b), preferably between 1.0 and 10.0 MPa, facilitating the recycling of hydrogen.

[0140] The separation step can advantageously be carried out by any method known to the person skilled in the art, such as, for example, a combination of one or more separators (drums) and / or one or more stripping columns, which or these separators (drums) and / or columns can optionally be fed with a stripping gas, for example a hydrogen-rich gas stream. The scrubbing / separation section of step c) can be made up, at least in part, of common or separate scrubbing and separation equipment.

[0141] In an optional embodiment of the invention, separation stage c) comprises the injection of an aqueous solution into the hydrotreated effluent resulting from stage b), followed by a scrubbing / separation section which advantageously comprises a separation phase making it possible to obtain at least one first aqueous effluent loaded with ammonium salts, a scrubbed liquid hydrocarbon effluent and a partially scrubbed gaseous effluent. Said first aqueous effluent loaded with ammonium salts and the scrubbed liquid hydrocarbon effluent are then separated in a knock-out drum to obtain said hydrocarbon effluent and said first aqueous effluent. The partially scrubbed gaseous effluent can be introduced in parallel into a scrub wash column, where it flows countercurrently against 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 scrubbed gaseous effluent and thus obtain the gaseous effluent, preferably essentially containing hydrogen, and an acid aqueous stream. The first aqueous effluent coming from the knock-out drum can optionally be mixed with the acid aqueous stream and optionally be used in a water recycle circuit for feeding the aqueous solution upstream of the scrub wash / separation section and / or the aqueous stream in the scrub wash column to separation stage c), in a mixture with the acid aqueous stream. The water recycle circuit can include the supply of water and / or a basic solution and / or a bleed that allows the dissolved salts to be discharged.

[0142] In another optional embodiment of the invention, separation stage c) may advantageously comprise a "high pressure" scrubbing / separation section, the pressure during operation of which is close to that of the hydrotreating stage a) and / or the hydrotreating stage b) and / or the optional hydrocracking stage g), preferably between 1.0 and 10.0 MPa, facilitating the recycling of hydrogen. This optional "high pressure" section of stage c) may be supplemented by a "low pressure" section, obtaining a hydrocarbon effluent devoid 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 stage f).

[0143] (2-step separation of transformation steps c)) In an optional embodiment of the invention, the separation step c) comprises the following substeps: c1) a separation step, to which the hydrotreated effluent resulting from step b) is fed; said step is carried out at a temperature between 200 and 450° C. and at a pressure substantially the same as that of step b); at least a gaseous effluent and a liquid effluent are obtained; part of the liquid effluent can be recycled upstream of steps a) and / or b), c2) a separation step, to which is fed the gaseous effluent resulting from step c1), another part of the liquid effluent resulting from step c1) and an aqueous solution; said step is carried out at a temperature between 20° C. and less than 200° C. and at a pressure substantially equal to or less than the pressure of step b); and at least a gaseous effluent, a first aqueous effluent and a hydrocarbon effluent are obtained.

[0144] (Step c1) According to the invention, the process can also include a separation stage c1), which is fed with the hydrotreated effluent resulting from stage b), said stage being carried out at a temperature between 200 and 450° C. and at a pressure substantially the same as that of stage b), and which obtains at least a gaseous effluent and a liquid effluent, part of which can be recycled upstream of stage a) and / or stage b).

[0145] The separation stage c1) is a separation stage called high- or medium-pressure high-temperature separation stage, also known to the skilled person under the name HHPS (Hot High Pressure Separator). This stage c1) therefore preferably uses a "high-temperature high-pressure" separator, the pressure being substantially equal to the operating pressure of stage b). The term "pressure substantially equal to the pressure of stage b)" is understood to mean a pressure of stage b) having a pressure difference of 0 to 1 MPa, preferably 0.005 to 0.3 MPa, particularly preferably 0.01 to 0.2 MPa with respect to the pressure of stage b). Preferably, the pressure of stage c1) is the pressure of stage b) reduced by pressure drop.

[0146] The temperature at which the separation is carried out is between 200 and 450° C., preferably between 220 and 330° C., particularly preferably between 240 and 300° C. According to a preferred alternative, with a view to recovering the greatest amount of heat, the separation is carried out at a temperature which is the highest possible but which is below the outlet temperature of stage b), which makes it possible to avoid or limit the reheating (and therefore the need for heating) of the effluent from stage b). According to another alternative, the effluent from stage b) can be reheated or cooled before the separation.

[0147] This separation step c1) can advantageously be carried out in any manner known to the person skilled in the art, such as, for example, a combination of one or more separators (drums) and / or one or more stripping columns, which or these separators (drums) and / or columns can optionally be fed with a stripping gas, for example a hydrogen-rich gas stream. Preferably, step c) is carried out by means of a single separator (drum).

[0148] Part of the liquid effluent can be recycled upstream of step a) and / or step b) and / or upstream of the pretreatment selective hydrogenation step a0). Recycling of part of the product obtained to at least one of the reaction steps or upstream thereof advantageously makes it possible, on the one hand, to dilute impurities and, on the other hand, to control the temperature in one or more reaction steps in which the reactions involved may be highly exothermic.

[0149] Advantageously, the amount of recycled liquid effluent resulting from step c), i.e. the recycled fraction of the product obtained, is adjusted so that the weight ratio of the recycle stream from step c) to the feedstock comprising plastic pyrolysis oil, i.e. the feedstock to be treated and fed to the entire process, is less than or equal to 10, preferably less than or equal to 7, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01, suitably greater than or equal to 0.1. Preferably, the amount of recycled liquid effluent resulting from step c) is adjusted so that the weight ratio of the recycle stream to the feedstock comprising plastic pyrolysis oil is between 0.01 and 10, preferably between 0.1 and 7, particularly preferably between 0.2 and 5. This recycle ratio makes it particularly possible to control the temperature rise in step a), since at a high recycle ratio the dilution rate of the feedstock is high, so that the temperature rise at the start of the reaction section of step a), particularly due to the dilution effect from the hydrogenation reaction of the diolefins, can thus be controlled by the dilution rate.

[0150] High pressure, high temperature separation makes it possible on the one hand to maximize the recovery of energy by hot recycling of a part of the liquid effluent, since the energy for achieving the required inlet temperature in stage a) and / or stage b) can be provided at least in part by the heat of a part of the liquid effluent resulting from stage c), making it possible to reduce, and even to eliminate, the optional preheating by direct heating of the feedstock above a temperature of more than 200° C., thus preventing the formation of gums. Furthermore, the fact of recycling at least a part of the liquid effluent at high pressure makes it possible to use the energy for pressurization in stage a) and / or stage b) economically.

[0151] The high-pressure, high-temperature separation, on the other hand, makes it possible to minimize the amount of light fractions (hydrocarbon fractions containing compounds with a boiling point below 175° C. or naphtha) contained in the liquid effluent recycled in step a) and / or step b). At this temperature, practically all of the light fractions of the effluent (naphtha) leave as gaseous effluent in the separation / scrubbing step c2), whereas as liquid phase, mainly the heavy fractions of the feedstock (hydrocarbon fractions containing compounds with a boiling point above 175° C. or middle distillates) are present. Thus, pH2p is advantageous in step a) and / or step b), since the light fractions (naphtha) could partially evaporate and lower pH2p if they were not at least partially removed during the high-pressure, high-temperature separation. The removal of the light fractions containing naphtha can optionally be increased by a slight pressure drop upstream of at least one separator used in step c1), even if this use is not preferred as a result of the energy losses associated with the pressure drop. Another option to increase the removal of the light fractions, including naphtha, may consist in carrying out a stripping, for example by injecting a hydrogen-rich gas in stage c1).

[0152] According to a preferred alternative, at least a portion of the hydrotreated liquid effluent resulting from step c) can advantageously either be cooled, preheated or maintained at the same temperature as at the outlet of the separation step c) and then advantageously recycled upstream of the hydrotreatment step a) and / or the hydrotreatment step b), depending on the temperature and the flow rate of the feedstock and of the hydrogen, the temperature of the incoming stream comprising said feedstock as a mixture of at least a portion of said liquid effluent resulting from step c) and hydrogen-rich gas being between 140 and 430°C, preferably between 220 and 350°C, particularly preferably between 260 and 330°C.

[0153] In the case where at least a part of the liquid effluent resulting from separation step c) is preheated before being recycled upstream of step a) and / or step b), said effluent optionally passes through at least one exchanger and / or at least one oven to adjust the temperature of said recycled liquid effluent before being recycled upstream of step a) and / or step b).

[0154] In the case where at least a part of the liquid effluent resulting from separation step c) is cooled before being recycled upstream of step a) and / or step b), said effluent optionally passes through at least one exchanger and / or at least one cooling tower to adjust the temperature of said recycled liquid effluent before being recycled upstream of step a) and / or step b).

[0155] The use of a recycle of at least a part of the liquid effluent resulting from step c), which can optionally either be cooled or preheated or maintained at the same temperature as at the outlet of separation step c), upstream of hydrogenation step a) and / or upstream of hydrotreatment step b), thus makes it possible to adjust, as required, the temperature of the streams entering step a) and / or step b), as required.

[0156] According to an alternative embodiment, the feedstock can be preheated by direct heating to a temperature ranging up to 200° C., preferably up to 180° C., particularly preferably up to 150° C., before being mixed with at least a portion of the effluent resulting from step c). Above this temperature, contact with the walls during direct heating can cause the formation of gums and / or coke, which can cause fouling of the system for heating the feedstock and the bed or beds of the catalyst and an increase in the pressure drop. Heating of the feedstock to a temperature above 150° C., preferably above 180° C., particularly preferably above 200° C., is preferably carried out by indirect heating with at least a portion of the effluent resulting from step c). The temperature increase of the feedstock above 150° C., preferably above 180° C., particularly preferably above 200° C. is therefore not brought about by contact with a heated wall but by mixing with a hotter liquid. According to another alternative form, heating of the feedstock to a temperature above 150°C, preferably above 180°C, particularly preferably above 200°C, is carried out by means of an oven or exchanger, e.g. an electric oven, proportioned to have a very low wall temperature compared to the temperature of the feedstock.

[0157] According to another alternative form, the feedstock is heated entirely by indirect heating with at least a portion of the effluent resulting from step c), in which case the feedstock is not preheated before being mixed with at least a portion of the effluent resulting from step c).

[0158] According to another alternative form, the feedstock is not heated by indirect heating with at least a portion of the effluent resulting from step c), in which case the feedstock and a portion of the recycled effluent resulting from step c) are mixed, the latter having substantially the same temperature as the feedstock or a lower temperature than the feedstock.

[0159] The other heated stream advantageously consists of a hydrogen-rich gaseous effluent originating from the hydrogen feed and / or a gaseous effluent resulting from separation stage c). At least a portion of this hydrogen-rich gaseous effluent originating from the hydrogen feed and / or of the gaseous effluent resulting from separation stage c) is advantageously injected upstream of stage a) and / or stage b), either in a mixture with at least a portion of the liquid effluent resulting from stage c) or separately. The hydrogen-rich gaseous stream can therefore advantageously be preheated either in a mixture with at least a portion of the liquid effluent or separately before mixing, preferably by passing through at least one exchanger and / or at least one oven or optionally through any other heating means known to the skilled person.

[0160] (Step c2) According to the invention, the treatment method comprises a separation step c2), advantageously carried out in at least one scrubbing / separation section, to which the first gaseous effluent, another part of the liquid effluent resulting from step c1) and an aqueous solution are fed, said step being carried out at a temperature between 20° C. and less than 200° C. and at a pressure substantially equal to or less than that of step b), to obtain at least a gaseous effluent, a first aqueous effluent and a hydrocarbon effluent.

[0161] The separation stage c2) is carried out in at least one knock-out drum, said to be a high or medium pressure cold knock-out drum, also known to the skilled person under the name CHPS (Cold High Pressure Separator). This stage c2) therefore preferably uses a "cold high pressure" separator, the pressure being substantially equal to the operating pressure of stage b). The term "pressure substantially equal to the pressure of stage b)" is understood to mean a pressure of stage b) having a pressure difference of 0 to 1 MPa, preferably 0.005 to 0.3 MPa, particularly preferably 0.01 to 0.2 MPa with respect to the pressure of stage b). Preferably, the pressure of stage c2) is the pressure of stage b) reduced by a pressure drop. Due to the fact that at least part of the separation stage c2) is operated at a pressure substantially identical to the operating pressure of stage b), the recycling of hydrogen is further facilitated.

[0162] The separation step c2) can also be carried out at a pressure lower than the pressure of step b).

[0163] Separation step c2) may also comprise a (first) step of separation at a pressure substantially equal to the operating pressure of step b), followed by at least one other separation step, carried out at the same or lower temperature and at a lower pressure as each preceding separation step of step c2).

[0164] The temperature at which the separation in step c2) is carried out is between 20°C and less than 200°C, preferably between 25 and 120°C, particularly preferably between 30 and 70°C.

[0165] It is important to operate in this temperature range (and therefore not overcool the hydrotreated effluent) at risk of plugging the lines due to precipitation of ammonium chloride salts.

[0166] The scrubbing / separation section of step c2) can be at least partially made up of common or separate scrubbing and separation equipment, which are well known (knockout drums, pumps, heat exchangers, scrubbing columns, etc., which can be operated at various pressures and temperatures). Separation step c2) can in particular be carried out in the same way as step c) above.

[0167] If one (or two) hydrocracking stages are present (see below), this stage c2) can furthermore be fed at least a portion of the hydrocracked effluent resulting from the optional hydrocracking stage g).

[0168] At least a part of the hydrocarbon effluent resulting from step c2) can be recycled as liquid quench upstream of step a) and / or step b) and / or step g). The injection of the hydrocarbon effluent resulting from step c2) can take place in the first catalyst bed of the reaction section of step a) and / or step b) and / or step g) or between the different catalyst beds of each section. If the hydrogenation reaction section of step a) comprises two reactors operating in a variable sequence mode, at least a part of the hydrocarbon effluent resulting from step c2) can be recycled between the two reactors.

[0169] (Step d) Separation of H2S contained in the first aqueous effluent) According to the invention, the treatment method comprises a step d) of separation of the H2S contained in the first aqueous effluent to obtain a gas phase containing H2S and the second aqueous effluent, said gas phase containing H2S being preferably at least partially recycled upstream of step a) and / or step b) and / or step g).

[0170] Step d) of the separation of the H2S contained in the first aqueous effluent is advantageously carried out by stripping with a gas stream, preferably an inert gas stream, in a stripping column. The stripping column is a distillation column into which a gas stream, preferably an inert gas stream, is injected at the bottom of the column. The gas phase containing the H2S is recovered at the top of the column and the second aqueous effluent is recovered at the bottom of the column. The inert gas stream can be hydrogen, nitrogen or steam. Preferably, step d) is carried out by steam stripping.

[0171] Stripping with a gas stream, preferably an inert gas stream, makes it possible to obtain a very low content of dissolved H2S in the second aqueous effluent at the bottom of the stripping column.

[0172] The pressure at which stage d) of the separation of H2S is carried out is generally between 0.5 and 1.5 MPa, preferably between 0.5 and 1 MPa, particularly preferably between 0.6 and 0.9 MPa.

[0173] The temperature at which stripping is carried out is generally between 80 and 150°C, preferably between 120 and 145°C (at the top and bottom of the column, respectively).

[0174] The flow rate of the inert gas stream is generally expressed as the flow rate of the inert gas stream (standard m 3 / hour(Sm 3 / h) versus the flow rate of the first aqueous effluent to be treated (volume (m) per hour at standard conditions (15°C, 0.1 MPa) 3 ) is 50 to 600Sm 3 / m 3 , preferably 200 to 400 Sm 3 / m 3 The standard m 3 is 1m at 0℃ and 0.1MPa 3 is understood to mean an amount of gas of a volume.

[0175] Stripping carried out under these operating conditions makes it particularly possible to separate H2S from said first aqueous effluent without entraining NH3 (NH3 remains mainly in the aqueous phase).

[0176] According to an alternative embodiment, in step d), part of the gas phase comprising H2S and the inert gas stream (water vapor) at the top of the stripping column is condensed and preferably at least partially reinjected as liquid reflux into the upper part of the stripping column. The condensation is generally carried out by cooling, for example with cold water, to a temperature of 30 to 65°C.

[0177] Liquid reflux allows the temperature at the top of the stripping column to be controlled / reduced.

[0178] The gas phase containing H2S withdrawn at the top of the stripping column is at least partially recycled upstream of step a) and / or step b) and / or upstream of the hydrocracking step g) and / or upstream of the pretreatment selective hydrogenation step a0) (if they are present) to act as a sulfiding agent for the catalyst(s). Before its recycling, it can be subjected to at least one further purification step, for example contact with a liquid or scrubbing with an amine.

[0179] According to another alternative, step d) of separation of the H2S contained in the first aqueous effluent can also be carried out by liquid / liquid extraction, in which an inert solvent or reactant is brought into contact with the aqueous effluent.

[0180] (Step e) Separation of the NH3 contained in the second aqueous effluent) According to the invention, the treatment process comprises a step e) of separation of the NH3 contained in the second aqueous effluent resulting from step d) to obtain a gas phase containing NH3 and the third aqueous effluent, said gas phase containing NH3 being preferably at least partially recycled upstream of step a) and / or step b) and / or step g).

[0181] Step e) of separation of NH3 contained in the second aqueous effluent is advantageously carried out by stripping with an inert gas stream in a stripping column. The gas phase containing NH3 is recovered at the top of the column and the third aqueous effluent is recovered at the bottom of the column. The inert gas stream can be hydrogen, nitrogen or steam. Preferably, step e) is carried out by steam stripping.

[0182] Stripping with an inert gas stream makes it possible to obtain a very low content of dissolved NH3 at the bottom of the stripping column and to recover a third aqueous effluent, which can be introduced into conventional wastewater treatment.

[0183] The pressure at which stage e) of separation of NH3 is carried out is generally between 0.1 and less than 0.5 MPa, preferably between 0.05 and 0.2 MPa.

[0184] The temperature at which stripping is carried out is generally from 80 to 150°C, preferably from 120 to 145°C (at the top and bottom of the column, respectively).

[0185] The flow rate of the inert gas stream is generally expressed as the flow rate of the inert gas stream (standard m 3 / hour(Sm 3 The flow rate of the feedstock to be treated (expressed as volume (m3) per hour at standard conditions (15°C, 0.1 MPa)) 3 ) is 50 to 600 Sm 3 / m 3 , preferably 200 to 400 Sm 3 / m 3 The standard m 3 is 1m at 0℃ and 0.1MPa 3 is understood to mean an amount of gas of a volume.

[0186] According to an alternative embodiment, in step e), part of the gas phase at the top of the stripping column containing NH3 and an inert gas stream (water vapor) is condensed and preferably at least partially reinjected into the upper part of the stripping column as liquid reflux. Condensation is generally carried out by cooling, for example with cold water, to a temperature of 30 to 65 ° C.

[0187] Liquid reflux allows the temperature at the top of the stripping column to be controlled / reduced.

[0188] According to an alternative embodiment, said gas phase containing NH3 can be at least partially recycled upstream of step a) and / or step b) and / or step g) and / or upstream of the selective hydrogenation step a0), advantageously in a stoichiometric amount suitable for the formation of salts during the separation / scrubbing step c).

[0189] (Fractionation Step f) (Optional) The process according to the invention may comprise a step of total or partial, preferably total, fractionation of the hydrocarbon effluent resulting from step c) to obtain at least a gas stream and at least two liquid hydrocarbon streams, said two liquid hydrocarbon streams being at least a first hydrocarbon fraction (naphtha fraction) comprising compounds having a boiling point below 175°C (naphtha fraction), in particular between 80 and 175°C, and a second hydrocarbon fraction (middle distillate fraction) comprising compounds having a boiling point above 175°C.

[0190] Stage f) makes it possible in particular to remove gases dissolved in the liquid hydrocarbon effluent, such as ammonia, hydrogen sulfide and light hydrocarbons having 1 to 4 carbon atoms.

[0191] The pressure at which the optional fractionation step f) is carried out is advantageously less than or equal to 3.0 MPa absolute, preferably between 0.5 and 2.5 MPa absolute.

[0192] According to one embodiment, step f) can be carried out in a section advantageously comprising at least one stripping tower, which is equipped with a reflux circuit comprising a reflux drum. Said stripping tower is fed with the liquid hydrocarbon effluent resulting from step c) and with a steam stream. The liquid hydrocarbon effluent resulting from step c) can optionally be heated before entering the stripping tower. The lightest compounds are then entrained at the top of the tower and in a reflux circuit comprising a reflux drum, where gas / liquid separation takes place. The gas phase comprising the light hydrocarbons is withdrawn as a gas stream from the reflux drum. The hydrocarbon fraction comprising compounds with a boiling point below 175° C. is advantageously withdrawn from the reflux drum. The hydrocarbon fraction comprising compounds with a boiling point above 175° C. is advantageously withdrawn at the bottom of the stripping tower.

[0193] According to another embodiment, the fractionation step f) can use a stripping column followed by a distillation column or a distillation column only.

[0194] Depending on the destination or use of the fraction resulting from fractionation step f), the skilled person will adjust the cut points in the stripping and / or distillation operations. For example, it may be necessary to adjust the end point of the naphtha fraction to 150, 175 or 200° C.

[0195] The first hydrocarbon fraction comprising compounds with a boiling point below 175° C. and the second hydrocarbon fraction comprising compounds with a boiling point above 175° C. can optionally be mixed and sent completely or partially to a steam cracking unit, at the end of which olefins can be (re)formed and participate in the formation of polymers. Preferably, only a portion of said fractions is sent to the steam cracking unit; at least a portion of the remaining portion is optionally recycled in at least one of the stages of the process and / or sent to a fuel storage unit derived from conventional petroleum feedstocks, such as a unit for the storage of naphtha, a unit for the storage of diesel or a unit for the storage of kerosene.

[0196] According to a preferred embodiment, the first hydrocarbon fraction comprising compounds having a boiling point below 175° C. is sent completely or partly to a steam cracking unit, while the second hydrocarbon fraction comprising compounds having a boiling point above 175° C. is sent to a hydrocracking stage g) and / or to a fuel storage unit.

[0197] In a particular embodiment, the optional fractionation step f) can make it possible to obtain, in addition to 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 can be sent completely or partially to a steam cracking unit and / or a unit for the storage of naphtha derived from conventional petroleum feedstocks; it can also be recycled; the middle distillate fraction can be sent completely or partially to a steam cracking unit or a unit for the storage of diesel derived from conventional petroleum feedstocks or can be recycled; the heavy fraction, if present, can be sent, for its part, at least partially to a steam cracking unit or sent to the hydrocracking step g).

[0198] In another particular embodiment, the optional fractionation step f) may make it possible to obtain, in addition to the gas stream, a naphtha fraction comprising compounds with a boiling point below 175° C., preferably between 80 and 175° C., a kerosene fraction comprising compounds with a boiling point above 175° C. and below 280° C., a diesel fraction comprising compounds with a boiling point above 280° C. and below 385° C. and a hydrocarbon fraction comprising compounds with a boiling point above 385° C., called the heavy hydrocarbon fraction. The naphtha, kerosene and / or diesel fractions may either be sent, completely or partially, to a steam cracking unit or to the naphtha, kerosene or diesel pools, respectively, originating from conventional petroleum feedstocks, or may be recycled. The heavy fraction, if present, may for its part be sent at least partially to a steam cracking unit or to the hydrocracking step g), if present.

[0199] In another particular embodiment, the naphtha fraction resulting from step f) containing compounds with a boiling point less than or equal to 175° C. is fractionated to give a heavy naphtha fraction containing compounds with a boiling point between 80 and 175° C. and a light naphtha fraction containing compounds with a boiling point less than 80° C., at least a portion of said heavy naphtha fraction being sent to an aromatics complex comprising at least one stage of naphtha reforming for the purpose of obtaining aromatics. According to this embodiment, at least a portion of the light naphtha fraction is sent to a steam cracking step h), described below.

[0200] The gaseous effluent(s) resulting from the fractionation stage f) may form the subject of one or more additional purification steps and one or more separation steps with the aim at least of recovering the light hydrocarbons, in particular ethane, propane and butanes, which may advantageously be sent separately or as a mixture to one or more furnaces of a steam cracking stage h) in order to increase the overall yield of olefins.

[0201] (Hydrocracking step g) (optional) According to an alternative embodiment, the process of the invention may comprise a hydrocracking step g) carried out after the separation step c) with at least a portion of said hydrocarbon effluent resulting from step c) or after the fractionation step f) with at least a portion of the second hydrocarbon cut comprising compounds with a boiling point above 175° C.

[0202] Advantageously, stage g) makes use of hydrocracking reactions well known to those skilled in the art, and more particularly makes it possible to convert heavy compounds, such as compounds with a boiling point above 175° C., into compounds with a boiling point below 175° C., contained in the hydrocarbon effluent resulting from fractionation stage f). Other reactions can be pursued, such as hydrogenation of olefins or aromatics, hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, etc.

[0203] Compounds with boiling points above 175°C have a high BMCI and contain more naphthenic, naphthenic aromatic and aromatic compounds relative to the lighter compounds, thus resulting in a higher C / H ratio. This high ratio causes coking in the steam cracker, therefore requiring a dedicated steam cracking furnace for this fraction. If it is desired to minimize the yield of these heavy compounds (middle distillate fractions) and maximize the yield of light compounds (naphtha fractions), these compounds can be at least partially converted by hydrocracking to light compounds, which are generally the preferred fractions for steam cracking units.

[0204] The process of the invention may therefore comprise a hydrocracking step g) carried out in a hydrocracking reaction section, using at least one fixed bed reactor having 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 with at least a portion of said hydrocarbon effluent resulting from step c) and / or at least a portion of a second hydrocarbon fraction resulting from step f) comprising compounds having a boiling point above 175° C., and a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450° C., with a hydrogen partial pressure between 1.5 and 20.0 MPa absolute and an hourly space velocity between 0.1 and 10.0 h . -1 to obtain a first hydrocracked effluent.

[0205] Therefore, the average temperature when the hydrocracking reaction section is advantageously used is 250 to 450°C, preferably 320 to 430°C, the hydrogen partial pressure is 1.5 to 20.0 absolute MPa, preferably 3 to 18.0 absolute MPa, and the hourly space velocity (HSV) is 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 g) is advantageously determined by the volume (m ) of fresh feedstock fed to step a). 3 ) Hydrogen 80~2000Sm 3 , preferably the volume (m ) of fresh feedstock fed to step a) 3 ) Hydrogen 200~1800Sm 3 The definitions of average temperature (WABT), HSV and hydrogen coverage correspond to those above.

[0206] Advantageously, the pressure under which said hydrocracking reaction section is carried out is comparable to the pressure used in the reaction section of the hydrogenation stage a) or of the hydrotreatment stage b).

[0207] Advantageously, said step g) is carried out in a hydrocracking reaction section comprising at least one, preferably 1 to 5, fixed bed reactors having n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, suitably between 2 and 5, said bed or beds each comprising 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, suitably between 2 and 5, said catalyst beds are preferably arranged in series within said reactor.

[0208] The hydrocracked effluent can be at least partially recycled into the hydrotreatment stage a) and / or the hydrotreating stage b) and / or the separation stage c). Preferably, it is recycled into the separation stage c).

[0209] The hydrocracking stage can be carried out in one stage (stage g)) or in two stages (stages g) and g'). When it is carried out in two stages, a separation of the effluent resulting from the first hydrocracking stage g) is carried out, making it possible to obtain a hydrocarbon fraction comprising compounds with a boiling point above 175° C. (middle distillate fraction), which is introduced into a second hydrocracking stage g') comprising a dedicated second hydrocracking reaction section different from the first hydrocracking reaction section g). This configuration is particularly suitable when it is desired to produce only a naphtha fraction.

[0210] The second hydrocracking stage g') is carried out in a hydrocracking reaction section using at least one fixed bed reactor having 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 with at least a portion of the first hydrocracked effluent from the first hydrocracking stage g) and a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature between 250 and 450°C, a hydrogen partial pressure between 1.5 and 20.0 absolute MPa and an hourly space velocity between 0.1 and 10.0 h -1to obtain a second hydrocracking effluent. Suitable operating conditions and catalysts used in the second hydrocracking stage are those described for the first hydrocracking stage. The operating conditions and catalysts used in the two hydrocracking stages may be the same or different.

[0211] The second hydrocracking stage is preferably carried out in a hydrocracking reaction section comprising at least one, preferably from 1 to 5, fixed bed reactors having n catalyst beds, n being an integer equal to or greater than 1, preferably from 1 to 10, suitably from 2 to 5, and wherein each of said beds comprises at least one, and preferably not more than 10, hydrocracking catalysts.

[0212] These operating conditions used in the hydrocracking stage or stages 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 products with a minimum of 80% by volume of compounds with a boiling point of less than or equal to 175° C., preferably less than 160° C., and advantageously less than 150° C. If the process is carried out in two hydrocracking stages, the conversion per pass in the second stage is kept moderate, maximizing the selectivity for compounds of the naphtha cut (with a boiling point of less than or equal to 175° C., in particular between 80° C. and less than or equal to 175° C.). The conversion per pass is limited by the use of a high recycle ratio over the loop of the second hydrocracking stage. This ratio is defined as the ratio of the feed flow rate of stage g') to the flow rate of the feedstock of stage a) or stage b); preferentially, this ratio is between 0.2 and 4, advantageously between 0.5 and 2.5.

[0213] The hydrocracked effluent from the second hydrocracking stage g') can be at least partially recycled into the hydrotreatment stage a) and / or into the hydrotreating stage b) and / or into the separation stage c). Preferably, it is recycled into the separation stage c).

[0214] The hydrocracking step or steps therefore do not necessarily make it possible to convert all the hydrocarbon compounds with a boiling point above 175° C. (middle distillate fraction) into hydrocarbon compounds with a boiling point below 175° C. (naphtha fraction). After the fractionation step f), a more or less significant proportion of compounds with a boiling point above 175° C. may thus remain. To increase the conversion, at least a part of this unconverted fraction can be introduced into a second hydrocracking step g'). Another part can be withdrawn. Depending on the operating conditions of the process, said withdrawal 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.

[0215] According to the invention, the hydrocracking stage or stages operate in the presence of at least one hydrocracking catalyst.

[0216] The hydrocracking catalyst or catalysts used in the hydrocracking step or steps are conventional hydrocracking catalysts known to those skilled in the art, of the bifunctional type combining acid functional groups with hydrodehydrogenation functional groups and optionally at least one binding matrix. The acid functional groups are those having a high specific surface area (typically 150-800 m2) which exhibits 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.

[0217] Preferably, the hydrodehydrogenation functional group of the hydrocracking catalyst or catalysts comprises at least one metal from group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, preferably from cobalt and nickel. Preferably, said catalyst or catalysts also comprise at least one metal from group VIB selected from chromium, molybdenum and tungsten, either alone or as a mixture, preferably from molybdenum and tungsten. Hydrodehydrogenation functional groups of the NiMo, NiMoW or NiW type are preferred.

[0218] Preferably, the content of metal from group VIII in the hydrocracking catalyst or catalysts 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 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.

[0219] Preferably, the content of metal from group VIB in the hydrocracking catalyst or catalysts is advantageously between 5% and 35% by weight, preferably between 10% and 30% by weight, the percentages being expressed as percentages by weight of oxide relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3 and WO3, respectively.

[0220] The one or more hydrocracking catalysts may optionally comprise at least one promoter element deposited on the catalyst, the promoter element being selected from the group formed by phosphorus, boron and silicon, and may optionally comprise at least one element from Group VIIA (chlorine and fluorine are preferred), and may optionally comprise at least one element from Group VIIB (manganese is preferred), and may optionally comprise at least one element from Group VB (niobium is preferred).

[0221] Preferably, the hydrocracking catalyst or catalysts comprise at least one amorphous or low-crystalline porous inorganic matrix of the oxide type chosen from alumina, silica, silica-alumina, aluminates, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide or clay, alone or as a mixture, preferably alumina or silica-alumina, alone or as a mixture.

[0222] Preferably, the silica-alumina contains more than 50% by weight alumina, preferably more than 60% by weight alumina.

[0223] Preferably, the hydrocracking catalyst or catalysts optionally also comprise a zeolite selected from Y zeolites, preferably USY zeolites alone or in combination with other zeolites as mixtures from Beta, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 or ZBM-30 zeolites, preferably USY zeolites alone or in combination with other zeolites as mixtures. Preferably, the zeolite is USY zeolite alone.

[0224] In the case where the catalyst comprises a zeolite, the content of zeolite in the hydrocracking catalyst or catalysts 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.

[0225] Suitable catalysts comprise, and preferably consist of, at least one metal from Group VIB, 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.

[0226] An even more suitable catalyst comprises, and preferably consists of, nickel, molybdenum, phosphorus, USY zeolite, and optionally beta zeolite, and alumina.

[0227] Other suitable catalysts include, and preferably consist of, nickel, tungsten, alumina and silica-alumina.

[0228] Other suitable catalysts include, and preferably consist of, nickel, tungsten, USY zeolite, alumina and silica-alumina.

[0229] The hydrocracking catalyst is, for example, in the form of an extrudate.

[0230] In an alternative embodiment, the hydrodehydrogenation functional group of the hydrocracking catalyst used in the second hydrocracking stage comprises at least one noble metal from group VIII, chosen alone or in a mixture from palladium and platinum, the content of noble metal from group VIII being 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.

[0231] According to another aspect of the invention, the hydrogenolysis catalyst further comprises 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 groups, or compounds containing a furan ring or sugars.

[0232] The preparation of catalysts for the hydrogenation, hydrotreating and hydrocracking stages is known and generally comprises a step of impregnation on the support of the metal from group VIII and of group VIB, if present, and optionally phosphorus and / or boron, followed by drying and then optionally calcination. In the case of additive catalysts, the preparation is generally carried out by simple drying without calcination after the introduction of the organic compound. The term "calcination" is understood here to mean a heat treatment under air or a gas containing oxygen at a temperature of 200° C. or higher. Before their use in the stages of the process, the catalysts are generally subjected to sulfurization to form the active body. The catalysts of stage a) can also be catalysts used in their reduced form, which therefore comprise a reduction step during their preparation.

[0233] The hydrogen-containing gas stream is fed to the selective hydrogenation, hydrogenation, hydrotreating and hydrocracking reaction sections and can consist of hydrogen feed and / or can consist of recycled hydrogen, especially resulting from separation step c). Preferably, an additional hydrogen-containing gas stream is advantageously introduced at the inlet of each reactor, especially at the inlet of each reactor operating in series and / or at the inlet of each catalyst bed starting 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 in which the reactions taking place are generally highly exothermic.

[0234] The hydrocarbon effluent or the one or more hydrocarbon streams thus obtained by the treatment of plastic pyrolysis oil by the method of the invention exhibit a composition that meets the specifications for the feedstock at the inlet of the steam cracking unit. In particular, the composition of the hydrocarbon effluent or the one or more hydrocarbon streams is preferably such that: the total content of metallic elements is less than or equal to 10.0 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 and suitably less than or equal to 0.5 ppm by weight, with the following corresponding: The content of silicon (Si) element is 5.0 ppm by weight or less, preferably 1 ppm by weight or less, suitably 0.6 ppm by weight or less, and / or the content of iron (Fe) element is 200 ppb by weight or less; the sulfur content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, and / or the nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, and suitably less than or equal to 5 ppm by weight; and / or - the asphaltene content is less than or equal to 5.0 ppm by weight; and / or the total content of elemental chlorine is equal to or less than 10 ppm by weight, preferably less than 1.0 ppm by weight; and / or - the mercury content is less than or equal to 5 ppb by weight, preferably less than 3 ppb by weight; and / or 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, and advantageously less than or equal to 0.1% by weight;

[0235] The content is given as the relative concentration by weight, percentage by weight (%), parts by million by weight (ppm) or parts by billion by weight (ppb) relative to the total weight of the stream of interest.

[0236] The method according to the invention therefore makes it possible to process plastic pyrolysis oils, obtaining an effluent which can be fully or partially injected into a steam cracking unit.

[0237] (Heavy metal adsorption step (optional)) Any gaseous effluent and / or any liquid effluent resulting from at least one of the separation steps c), d) or e) or from the fractionation step f) can be subjected to an optional step of adsorption of heavy metals.

[0238] The gaseous effluent may in particular be the gaseous effluent resulting from step c) and / or the H2S-containing gas phase resulting from step d) and / or the NH3-containing gas phase resulting from step e) and / or the gaseous effluent resulting from the fractionation step f).

[0239] The liquid effluent may in particular be the hydrocarbon effluent resulting from step c) and / or the first and / or second hydrocarbon fraction resulting from step f).

[0240] The optional adsorption step makes it possible to eliminate or reduce the amount of metal impurities, in particular heavy metals, such as arsenic, zinc, lead, and especially mercury, that may be present in the gaseous and liquid effluents. Metal impurities, in particular heavy metals, are present in the feedstock. Some impurities, in particular those based on mercury, can be converted in one of the steps of the method according to the invention. Their converted form is easier to capture. Their elimination or reduction may be particularly necessary when at least a portion of the gaseous and liquid effluents is intended to be sent to a step with strict specifications for metal impurities, for example a steam cracking step, either directly or after being subjected to one or more optional additional steps, for example a fractionation step f).

[0241] The optional step of adsorption of the gaseous effluent and / or hydrocarbon effluent resulting from the process according to the invention is therefore advantageously carried out, in particular when at least one of these effluents or feedstocks contains, respectively, more than 20 ppb by weight, in particular more than 15 ppb by weight, of heavy metal elements (As, Zn, Pb, Hg, etc.), and in particular when at least one of these effluents or feedstocks contains, respectively, more than 10 ppb by weight, more particularly more than 15 ppb by weight, of mercury.

[0242] The optional adsorption step is advantageously carried out at a temperature between 20 and 250° C., preferably between 40 and 200° C., and at a pressure between 0.15 and 10.0 MPa absolute, preferably between 0.2 and 1.0 MPa absolute.

[0243] Said optional adsorption step can be carried out by means of any adsorbent known to the person skilled in the art making it possible to reduce the amount of such pollutants.

[0244] According to an alternative form, said optional adsorption step is carried out in an adsorption section operated in the presence of at least one adsorbent comprising a porous support and at least one active phase which may be based on sulfur in elemental form, or in the form of a metal sulfide or metal oxide, or in elemental form.

[0245] The porous support can be chosen without distinction from the family of alumina, silica-alumina, silica, zeolites and / or activated carbon. Advantageously, the porous support is based on alumina. The specific surface area of ​​the support is generally between 150 and 600 m 2 / g, preferably 200 to 400m 2 / g, more preferably 150 to 320 m 2 The specific surface area of ​​the adsorbent is the area measured by the BET method as described above.

[0246] The active phase is based on sulfur in elemental form or in the form of metal sulfides or metal oxides or in the form of metals in elemental form. Preferably, the active phase is in the form of metal sulfides, in particular sulfides of metals from the group selected from copper, molybdenum, tungsten, iron, nickel or cobalt.

[0247] Advantageously, the active phase of the sorbent comprises sulphur in an amount ranging from 1% to 70% by weight, preferably from 2% to 25% by weight and highly preferably from 3% to 20% by weight, relative to the total weight of the sorbent.

[0248] Advantageously, the proportion by weight of metal relative to the total weight of the adsorbent is generally between 1% and 60%, preferably between 2% and 40%, better still between 5% and 30% and highly preferably between 5% and 20%.

[0249] The residence time in the adsorption section is generally from 1 to 180 minutes.

[0250] The adsorption section can include one or more adsorption columns. When the adsorption section includes two adsorption columns, one mode of operation can be "swing" operation, where one of the columns is on-line, i.e., in operation, while the other column is in reserve. Another mode of operation is to have at least two columns operated in series in a variable sequence mode.

[0251] Preferably, the adsorption section comprises one or more adsorption columns for the gaseous effluents and one or more adsorption columns for the liquid effluents.

[0252] (Steam Cracking Stage h) (Optional) The hydrocarbon effluent resulting from the separation stage c) or at least one of the two liquid hydrocarbon streams resulting from the optional stage f) can be sent completely or partly to a steam cracking stage h).

[0253] Advantageously, the gaseous effluent(s) resulting from the separation stage c) and / or the fractionation stage f) and containing ethane, propane and butanes can also be sent completely or partly to a steam cracking stage h).

[0254] Said steam cracking stage h) is advantageously carried out in at least one pyrolysis furnace, the temperature being between 700 and 900°C, preferably between 750 and 850°C, the pressure being between 0.05 and 0.3 relative MPa. The residence time of the hydrocarbon compounds is generally less than or equal to 1.0 second (denoted s), preferably between 0.1 and 0.5 s. Advantageously, steam is introduced upstream of the optional steam cracking stage h), after the separation stage c) (or fractionation stage f)). 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 compounds at the inlet of stage h). Optional stage h) is preferably carried out in several pyrolysis furnaces in parallel, adapting the operating conditions to the various streams, especially resulting from stage f), feeding stage h), and also managing the decoking times of the tubes. The furnace comprises one or several tubes arranged in parallel. A furnace may also refer to a group of furnaces operating in parallel. For example, a furnace may be dedicated to the cracking of a hydrocarbon fraction containing compounds with a boiling point below 175° C.

[0255] The effluents from the various steam cracking furnaces are generally recombined before separation with the aim of constituting the effluent. It is understood that the steam cracking stage h) includes not only the steam cracking furnaces, but also sub-stages related to steam cracking that are well known to those skilled in the art. These sub-stages can include, in particular, heat exchangers, columns and catalytic reactors as well as recycle to the furnaces. The columns generally make it possible to fractionate the effluent with the aim of recovering at least a light fraction comprising hydrogen and compounds having 2 to 5 carbon atoms, as well as a fraction comprising pyrolysis gasoline and possibly a fraction comprising pyrolysis oil. The columns make it possible to separate the various components of the light fraction of the fractionation, recovering at least a fraction rich in ethylene (C2 fraction) and a fraction rich in propylene (C3 fraction) and possibly a fraction rich in butenes (C4 fraction). The catalytic reactors make it possible in particular to carry out hydrogenation of the C2, C3 and indeed even C4 fractions and pyrolysis gasoline. Saturated compounds, especially those having 2 to 4 carbon atoms, are advantageously recycled to the steam cracker to increase the overall yield of olefins.

[0256] This steam cracking step h) makes it possible to obtain from at least one effluent containing olefins containing 2, 3 and / or 4 carbon atoms (i.e. C2, C3 and / or C4 olefins) a satisfactory content, in particular 30% by weight or more, in particular 40% by weight or more, indeed even 50% by weight or more, of total olefins containing 2, 3 and 4 carbon atoms, relative to the weight of the steam cracking effluent in question. Said C2, C3 and C4 olefins can then advantageously be used as polyolefin monomers.

[0257] According to a preferred embodiment of the present invention, the method for the treatment of a feedstock containing plastic pyrolysis oil preferably comprises linking together, preferably in the given order, the following steps: - a hydrotreating step b), a separation / scrubbing step c), a step d) of separation of H2S with recycle of H2S within step b), and a step e) of separation of NH3. - a hydrogenation step a), a hydrotreating step b), a separation / scrubbing step c), a step d) of separation of H2S with recycling of H2S in steps a) and / or b) and a step e) of separation of NH3. - a hydrogenation step a), a hydrotreating step b), a separation / scrubbing step c), a step d) of separation of H2S with recycling of H2S in steps a) and / or b), a step e) of separation of NH3 and a fractionation step f). - hydrogenation step a), hydrotreating step b), separation / scrubbing step c), step d) of separation of H2S with recycling of H2S in steps a) and / or b), step e) of separation of NH3, as well as fractionation step f) and introduction of a hydrocarbon fraction comprising compounds with a boiling point above 175°C in hydrocracking step g), the hydrocracked effluent being recycled into step c).

[0258] All embodiments may further comprise, and preferably consist of, a pretreatment step a0).

[0259] All embodiments may further comprise, and preferably consist of, a steam cracking step h).

[0260] (Analysis methods used) The analytical methods and / or standards used to determine the characteristics of the various streams, in particular the feedstocks to be treated and the effluents, are known to the person skilled in the art. They are specifically listed below for information. Other methods that are referred to as equivalent, in particular equivalent IP, EN or ISO methods, can also be used.

[0261] [Table 1]

[0262] (1)The MAV method is described in the paper 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, pp. 57-68.

[0263] (List of Drawings) The details of the elements referenced in Figures 1 and 2 allow for a better understanding of the invention, but the invention is not limited to the specific embodiments shown in Figures 1 and 2. The various embodiments presented can be used alone or in combination with each other, and there are no combination limitations.

[0264] FIG. 1 represents a diagram of a particular embodiment of the method of the present invention, which includes: - step a) (optional): hydrogenation of a hydrocarbon feedstock (1) resulting from the pyrolysis of plastics in the presence of a hydrogen-rich gas (2) and optionally amines provided by stream (3) and optionally a sulfiding agent provided (especially at the beginning of the cycle) by stream (4); - a hydrotreating stage b): to which is fed a hydrocarbon effluent (5) resulting from the hydrotreating stage a), if present, and a hydrogen-rich gas stream (6); - a separation step c) in which the effluent (7) resulting from the hydrotreatment step b) is fed in the presence of an aqueous solution (10) to obtain at least a gaseous effluent (11), a first aqueous effluent (12) containing H2S, HCl and NH3, and a hydrocarbon effluent (13); - a separation stage d); separation of the H2S contained in the first aqueous effluent (12) is preferably carried out by stripping with a stream (19) containing water vapor; it is possible to obtain a gas phase (20) containing H2S and a second aqueous effluent (21). Said gas phase containing H2S is at least partially recycled upstream of stage a) (if it is present) and / or stage b), preferably upstream of stage a); this recycling of the H2S-containing phase (20) makes it possible to maintain the catalyst of stages a) and / or b) in the sulfidic form and therefore to reduce the contribution of the sulfiding agent (4), - a separation stage e); separation of the NH3 contained in the second aqueous effluent (21) is preferably carried out by stripping with a stream containing stream (19); it is possible to obtain a gas phase (22) containing NH3 and a third aqueous effluent (23).

[0265] Figure 2 represents a diagram of another particular embodiment of the process of the invention, based on the diagram of Figure 1. This diagram further comprises step c), which is carried out in two stages, followed by a fractionation step f) and a hydrocracking step g).

[0266] The hydrogenation step a) and the hydrotreatment step b) are carried out as described in Figure 1. The separation step c), which is carried out in two stages, comprises in particular: - a step c1 of separation of the hydrotreated effluent (7) carried out at high pressure and high temperature (HHPS); obtaining at least a gaseous effluent (8) and a liquid effluent (9); a part (9a) of the liquid effluent (9) can be recycled (not shown) upstream of step a) or upstream of step b), - a separation stage c2 carried out in a high pressure, low temperature (CHPS) reactor; fed with the gaseous effluent (8), the other part (9b) of the liquid effluent resulting from stage c1) and an aqueous solution (10), making it possible to obtain at least a gaseous effluent (11) containing hydrogen, an aqueous effluent (12) containing dissolved salts and dissolved H2S and NH3, and a hydrocarbon effluent (13).

[0267] The steps d) of separation of H2S and e) of separation of NH3 are carried out as described in Figure 1. The recycling of the H2S-containing phase (20) is carried out as well. It can also be recycled, at least in part, into the hydrocracking step g).

[0268] Optionally, a step f) of fractionation of the hydrocarbon effluent (13) is carried out, making it possible to obtain at least a gaseous effluent (14) and a first hydrocarbon fraction (15) (naphtha fraction) comprising compounds having a boiling point below 175° C. and a second hydrocarbon fraction (16) (middle distillate fraction) comprising compounds having a boiling point above 175° C.

[0269] At the end of step f), a part of the first hydrocarbon fraction (15) comprising compounds with a boiling point below 175° C. can be sent to a steam cracking process (not shown). Another part of the first hydrocarbon fraction (15) can be fed to the hydrogenation step a) and / or to the hydrotreating step b) (recycle not shown).

[0270] In FIG. 2, at least a portion of the second hydrocarbon fraction (16) resulting from step f) and comprising compounds with a boiling point above 175° C. is fed to a hydrocracking step g), which is carried out by at least one hydrocracking reactor comprising at least one hydrocracking catalyst. and fed with hydrogen (17). The hydrocracked effluent (18) can be recycled between separation stages c1) and c2) or upstream of separation stage c) (not shown).

[0271] Instead of injecting the amine stream (3) at the inlet of the hydrogenation stage a), it is possible, depending on the characteristics of the feedstock, to inject it at the inlet of the hydrotreatment stage b), at the inlet of the separation stage c), at the inlet of the hydrocracking stage g), if present, or not to inject it at all.

[0272] Only the main stages, together with the main flows, are shown in Figures 1 and 2, which allows the invention to be better understood. It is clearly understood that all the equipment necessary for the operation (drums, pumps, exchangers, ovens / furnaces, columns, etc.) is present, even if not shown. It is also understood that a hydrogen-rich gas stream (feed or recycle), as described above, can be injected at the inlet of each reactor or catalyst bed, or between two reactors or two catalyst beds. Means for hydrogen purification and recycling well known to those skilled in the art can also be used.

[0273] (Example) (Example 1 (according to the present invention)) The flow rate of the feedstock (1) treated in this process is 10,000 kg / h (10 T / h), which is a plastic pyrolysis oil (i.e. comprising 100% by weight of said plastic pyrolysis oil) exhibiting the characteristics indicated in Table 2.

[0274] [Table 2]

[0275] (1) The MAV method is described in the paper 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, pp. 57-68.

[0276] 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 an alumina-supported NiMo-type hydrogenation catalyst under the conditions shown in Table 3.

[0277] [Table 3]

[0278] The conditions shown in Table 3 correspond to the conditions at the start of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0279] At the end of the hydrogenation step a), the observed conversions (=(initial concentration-final concentration) / initial concentration) are given in Table 4.

[0280] [Table 4]

[0281] The effluent (5) coming from the hydrogenation stage a) is subjected directly, without separation, to a hydrotreating stage b), which is carried out in a fixed bed, in the presence of hydrogen and a hydrotreating catalyst of the NiMo type supported on alumina, under the conditions shown in Table 5.

[0282] [Table 5]

[0283] The conditions shown in Table 5 correspond to the conditions at the start of the cycle, with the average temperature (WABT) increased by 1° C. per month to compensate for catalyst deactivation.

[0284] The effluent (7) resulting from the hydrotreatment stage b) is subjected to a separation stage c): a water stream (10) is injected into the effluent resulting from the hydrotreatment stage b): the mixture is then treated in a column for scrubbing sour gas and in a knock-out drum to obtain a gas fraction and a liquid effluent. The yields of the various fractions obtained after separation are given in Table 6 (the yields correspond to the ratio of the weight of the various products obtained to the weight of the feedstock upstream of stage a), expressed as a percentage and indicated in % w / w).

[0285] [Table 6]

[0286] All or a portion of the resulting liquid fraction can then be upgraded in a steam cracking step to form olefins which can be polymerized to form recycled plastics.

[0287] The pyrolysis oil feedstock contains only a small amount of sulfur (170 ppm by weight). This sulfur is present in the form of sulfur-containing molecules and is hydrogenated and converted to H2S in the reaction section. This H2S contributes in the form of H2S partial pressure (pH2Sp) in the reactor to the maintenance of the sulfide phase of the alumina-supported NiMo catalyst. Nevertheless, the pH2Sp obtained with this content of sulfur-containing compounds in the feedstock (170 ppm by weight) is insufficient to keep the catalyst in the sulfide phase throughout the cycle. This will result in a rapid deactivation of the catalyst's activity if nothing is done. It is therefore recommended to add H2S to the reaction system to achieve a sufficient pH2Sp. This addition of H2S can be done in the form of injection of dimethyl disulfide (DMDS) into the pyrolysis oil feedstock at the inlet of the unit. DMDS decomposes easily to give CH4 and H2S as soon as it comes into contact with the catalyst, thus generating sufficient pH2Sp to keep the catalyst in the sulfide form. This method of operation causes a large consumption of DMDS which is detrimental to the economics of the process.

[0288] Another method forming the subject of the present invention is to recover the H2S discharged in the aqueous effluent by means of a double stripping of the aqueous effluent and to reinject this H2S at the inlet of the unit by dissolution in the pyrolysis oil feedstock.

[0289] Injection of DMDS and / or recycling of H2S at the inlet of the unit can both help to maintain a sufficient pH2Sp in the reaction system, as well as to neutralize any NH3 resulting from the hydrogenation of nitrogen-containing molecules, since H2S reacts with NH3 to form ammonium sulfide, which is virtually completely scrubbed and transferred into the aqueous effluent (stream (12)), making it possible to free the gas stream from the presence of ammonia at the top outlet of the stabilization column (stream (11)). This gas stream, freed from the presence of ammonia, can therefore be sent directly to the steam cracker to maximize the production of olefins.

[0290] The advantage of recycling the H2S stream compared to injecting DMDS, whether in the situation of maintaining sufficient pH2Sp or in the case of delivering a gas stream liberated from that ammonia, is therefore to conserve the amount of DMDS throughout the cycle.

[0291] The four operation cases are shown in Table 7.

[0292] (Case 1): Simple sour water stripping and DMDS injection are performed to maintain a pH2Sp sufficient to keep the catalyst in the sulfide phase.

[0293] (Case 2): Strip twice as much sour water and recycle at the inlet of the unit a H2S dominated stream from the top of the first stripping tower, only maintaining a pH2Sp sufficient to keep the catalyst in the sulfide phase. This case is consistent with the present invention.

[0294] (Case 3): Simple stripping of sour water and injection of DMDS to maintain a pH2Sp sufficient to keep the catalyst in the sulfide phase, and also neutralize all NH3 and deliver an NH3-free gas stream.

[0295] (Case 4): Stripping twice as much sour water, recycling to the inlet of the unit a stream predominantly H2S from the top of the first stripping tower to maintain a pH2Sp sufficient to keep the catalyst in the sulfide phase, and also neutralizing all NH3 and delivering a NH3-free gas stream. This case is consistent with the present invention.

[0296] It may be observed that the invention makes it possible to save 19 kg / h of DMDS when it is a question of maintaining a minimum pH2Sp in order to keep the catalyst in the sulphide form.

[0297] It may be observed that the present invention allows even greater savings, namely a saving of 65 kg / h of DMDS (75-10=65 kg / h) to deliver an ammonia-free gas phase. Table 7: Operation cases

[0298] [Table 7A]

[0299] [Table 7B]

[0300] [Brief description of the drawings]

[0301] [Figure 1] 1 depicts a diagram of a particular embodiment of the method of the present invention. [Diagram 2] 2 represents a diagram of another particular embodiment of the method of the invention based on the diagram of FIG. 1.

Claims

1. A method for processing a feedstock containing plastic pyrolysis oil, comprising the following steps: a) A hydrogenation step carried out in a hydrogenation reaction section, depending on the circumstances; using at least one fixed-bed reactor having n catalyst beds, where n is an integer of 1 or more, each containing at least one type of hydrogenation catalyst, supplying at least the feed material and a hydrogen-containing gas stream to the hydrogenation reaction section, the average temperature when using the hydrogenation reaction section being 140 to 400°C, the hydrogen partial pressure being 1.0 to 10.0 absolute MPa, and the spatiotemporal velocity being 0.1 to 10.0 h －１ It is; obtain hydrogenated effluent, b) A hydrogenation step carried out in a hydrogenation reaction section containing at least one hydrogenation catalyst; at least the feedstock or the hydrogenated effluent generated from step a) and a hydrogen-containing gas stream are supplied to the hydrogenation reaction section, the average temperature when using the hydrogenation reaction section is 250 to 430°C, the hydrogen partial pressure is 1.0 to 10.0 absolute MPa, and the spatiotemporal velocity is 0.1 to 10.0 h －１ It is; to obtain hydrogenated effluent, c) Separation stage; the hydrogenated effluent produced from stage b), and optionally the hydrocracking effluent produced from stage g), and an aqueous solution are fed; at least a gaseous effluent, a first aqueous effluent, and a hydrocarbon effluent are obtained. d) H contained in the first aqueous effluent ２ Stage of separation of S; H ２ A gas phase containing S and a second aqueous effluent are obtained; H ２ The gas phase containing S is optionally recycled, at least partially, upstream of step a) and / or step b) and / or step g). e) NH contained in the second aqueous effluent ３ The stage of separation; NH ３ A gas phase containing and a third aqueous effluent are obtained; NH ３ The gas phase containing the gas is, in some cases, recycled, at least in part, upstream of step a) and / or step b) and / or step g). f) Depending on the case, a fractionation step of all or part of the hydrocarbon effluent produced in step c); obtaining at least a gaseous effluent, at least a first hydrocarbon fraction containing compounds with a boiling point of 175°C or less, and a second hydrocarbon fraction containing compounds with a boiling point greater than 175°C. g) A hydrocracking stage, optionally carried out in the hydrocracking reaction section; using at least one fixed bed reactor having n catalyst beds, where n is an integer of 1 or more, each containing at least one hydrocracking catalyst, and feeding into the hydrocracking reaction section at least a part of the hydrocarbon effluent resulting from step c) and / or at least a part of a second hydrocarbon fraction containing compounds having a boiling point above 175 °C resulting from step f), and a gas stream containing hydrogen, the average temperature when using the hydrocracking reaction section being 250 to 450 °C, the hydrogen partial pressure being 1.5 to 20.0 absolute MPa, and the space velocity being 0.1 to 10.0 h －１ ; to obtain a first hydrocracked effluent.

2. H generated from step d) ２ The method according to claim 1, wherein the gas phase containing S is recycled at least partially upstream of step a) and / or step b) and / or step g).

3. The method according to claim 1, comprising hydrogenation step a).

4. The method according to claim 1, including fractionation step f).

5. The method according to claim 1, comprising step g) hydrocracking.

6. H contained in the first aqueous effluent ２ The method according to claim 1, wherein the separation step d) of S is performed by stripping the effluent with a flow containing water vapor, the pressure at which is 0.5 to 1 MPa and the temperature at which is 80 to 150°C.

7. NH contained in the second aqueous effluent ３ The method according to claim 1, wherein the separation step e) is performed by stripping the effluent with a flow containing water vapor, the pressure at which is 0.1 to 0.5 MPa and the temperature at which is 80 to 150°C.

8. The separation step c) is the method according to claim 1, comprising the following steps: c1) Separation stage; supplying the hydrogenated effluent produced in stage b); the temperature during this stage is 200-450°C and the pressure is substantially the same as that in stage b); obtaining at least gaseous effluent and liquid effluent; optionally recycling a portion of the liquid effluent upstream of stage a) and / or stage b). c2) Separation step; feeding the gaseous effluent produced in step c1), another portion of the liquid effluent produced in step c1), and an aqueous solution; the temperature during this step is between 20°C and less than 200°C, and the pressure is substantially the same as or less than the pressure in step b); at least gaseous effluent, a first aqueous effluent, and hydrocarbon effluent are obtained.

9. The method according to claim 1, comprising at least one step a0) of pretreatment of a feedstock containing plastic pyrolysis oil, optionally as a mixture with hydrocarbon effluent resulting from step c), wherein the pretreatment step is performed upstream of step a) and / or upstream of step b), and comprising a filtration step and / or a centrifugation step and / or an electrostatic separation step and / or an aqueous scrubbing step and / or an adsorption step and / or a selective hydrogenation step.

10. The method according to claim 1, wherein the hydrocarbon effluent produced from separation step c), or at least one of the two liquid hydrocarbon fractions produced from step f), is sent entirely or partially to steam decomposition step h), and step h) is carried out in at least one pyrolysis furnace, the temperature being 700 to 900°C, and the pressure being 0.05 to 0.3 relative MPa.

11. NH generated from step e) ３ The method according to claim 1, wherein the gas phase containing is recycled at least partially upstream of step a) and / or step b) and / or step g).

12. The method according to claim 1, wherein a flow containing a nitrogen compound and / or a sulfur compound is injected upstream of step a) and / or upstream of step b).

13. The method according to claim 1, wherein the hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional element comprising at least one element from Group VIII and at least one element from Group VIB, or at least one element from Group VIII.

14. The method according to claim 1, wherein the hydrogenation catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional element containing at least one element from Group VIII and / or at least one element from Group VIB.

15. The process further includes a second hydrocracking step g') carried out in a hydrocracking reaction section, and uses at least one fixed-bed reactor having n catalyst beds, where n is an integer of 1 or more, each containing at least one type of hydrocracking catalyst, and supplies to the hydrocracking reaction section at least a portion of the first hydrocracking effluent produced from the first hydrocracking step g) and a gas stream containing hydrogen, and the temperature when using the hydrocracking reaction section is 250 to 450°C, the hydrogen partial pressure is 1.5 to 20.0 absolute MPa, and the spatiotemporal velocity is 0.1 to 10.0 h －１ The method according to claim 1, wherein a second hydrocracking effluent is obtained.

16. The method according to claim 1, wherein the hydrocracking catalyst comprises a support selected from a combination of alumina halides, boron and aluminum oxides, amorphous silica-alumina and zeolites, and a hydrodehydrogenating functional metal comprising at least one metal from Group VIB selected individually or as a mixture from chromium, molybdenum and tungsten, and / or at least one metal from Group VIII selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

17. A product obtained by the method according to any one of claims 1 to 16.

18. The product according to claim 17, wherein the product comprises the following in relation to the total weight of the product: - Metallic elements; total content is 10.0 ppm by weight or less. - Contains iron: the content is 200 ppb by weight or less, and / or - Silicon element; content is 5.0 ppm by weight or less, and / or - Sulfur; the content is 100 ppm by weight or less, and / or - Nitrogen; content is 100 ppm by weight or less, and / or - Chlorine element; the content is 10 ppm by weight or less, and / or - Mercury; the content is 5 ppb by weight or less.

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