Methods for treating plastic pyrolysis oil, including hydrogenation steps

Abstract

This invention relates to a method for treating plastic pyrolysis oil, comprising: a) hydrogenating the feedstock in the presence of at least hydrogen and at least one hydrogenation catalyst at an average temperature of 140-340°C to obtain a hydrogenated effluent, wherein the outlet temperature of step a) is at least 15°C higher than the inlet temperature of step a); b) hydrogenating the hydrogenated effluent in the presence of at least hydrogen and at least one hydrogenation treatment catalyst to obtain a hydrogenated treated effluent, wherein the average temperature of step b) is higher than the average temperature of step a); c) separating the hydrogenated treated effluent in the presence of an aqueous stream at a temperature of 50-370°C to obtain at least one gaseous effluent, an aqueous liquid effluent, and a hydrocarbon liquid effluent.

Description

Technical Field

[0001] This invention relates to a method for treating plastic pyrolysis oil to obtain a hydrocarbon effluent, which can be upgraded by direct incorporation into a naphtha or diesel storage unit or as feedstock for a steam cracking unit. More specifically, this invention relates to a method for treating feedstock derived from the pyrolysis of plastic waste to at least partially remove relatively large amounts of impurities that may be present in the feedstock. Existing technology

[0002] Plastics obtained from collection and sorting channels can undergo a pyrolysis step to obtain pyrolysis oil in particular. These plastic pyrolysis oils are typically burned to generate electricity and / or used as fuel in industrial boilers or urban heating.

[0003] Another approach to modifying plastic pyrolysis oil is to use it as feedstock in steam cracking units to (re)generate olefins, which are constituent monomers of certain polymers. However, plastic waste is typically a mixture of several polymers, such as polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, and polystyrene. Furthermore, depending on the application, plastics may contain other compounds besides polymers, such as plasticizers, pigments, dyes, or polymerization catalyst residues. Plastic waste may also contain small amounts of biomass, for example, from household waste. On the one hand, the treatment of waste, especially storage, mechanical processing, sorting, and pyrolysis, and on the other hand, the storage and transportation of pyrolysis oil, can cause corrosion. As a result, the oil obtained from the pyrolysis of plastic waste contains many impurities, particularly dienes, metals, especially iron and silicon, or halogenated compounds, especially chlorinated compounds, heteroelements such as sulfur, oxygen, and nitrogen, and insoluble substances, often in high concentrations and incompatible with steam cracking units or units downstream of steam cracking units, particularly polymerization and selective hydrogenation methods. These impurities can cause operational problems, particularly corrosion, coking, or catalytic deactivation, or incompatibility issues in the application of the target polymer. The presence of dienes can also lead to instability in pyrolysis oils, characterized by the formation of gums. Gum and insoluble substances that may be present in pyrolysis oils can cause clogging problems in the process.

[0004] Furthermore, during the steam cracking step, the yields of light olefins, particularly ethylene and propylene, sought by petrochemicals, are highly dependent on the quality of the feedstock sent to the steam cracker. The BMCI (Mining Bureau Relevant Index) is commonly used to characterize hydrocarbon fractions. This index, developed for hydrocarbon products derived from crude oil, is calculated from measurements of density and average boiling point: it equals 0 for straight-chain alkanes and 100 for benzene. Therefore, its value is always higher if the analyzed product has an aromatic fused structure; cycloalkanes have an intermediate BMCI between alkanes and aromatic compounds. Generally, the yield of light olefins increases with increasing alkane content and therefore with decreasing BMCI. Conversely, an increase in BMCI leads to an increase in the undesirable yields of heavy compounds and / or coke.

[0005] WO 2018 / 055555 presents a general method for recycling plastic waste, which is very broad and relatively complex, ranging from various steps of pyrolysis to steam cracking. The method in patent application WO 2018 / 055555 specifically includes a step of hydrotreating the liquid phase obtained directly from pyrolysis, preferably under very stringent conditions, particularly in terms of temperature, for example at 260-300°C; a step of separating the hydrotreated effluent; and a step of subsequently hydrodealkylating the separated heavy effluent, preferably at high temperatures, for example at 260-400°C.

[0006] Unpublished patent application FR 20 / 01758 describes a method for processing plastic pyrolysis oil, which includes:

[0007] a) Selectively hydrogenating olefins contained in the feedstock in the presence of hydrogen and a selective hydrogenation catalyst to obtain a hydrogenated effluent;

[0008] b) Hydrotreating the hydrotreated effluent in the presence of hydrogen and a hydrotreatment catalyst to obtain a hydrotreated effluent;

[0009] c) At a temperature of 50-370°C, in the presence of an aqueous stream, the hydrogenation treatment effluent is separated to obtain a gaseous effluent, an aqueous liquid effluent, and a hydrocarbon liquid effluent;

[0010] d) Optionally, the step of fractionating all or part of the hydrocarbon effluent obtained from step c) to obtain a gaseous stream and at least two hydrocarbon streams, said at least two hydrocarbon streams may be a naphtha fraction and a heavier fraction;

[0011] e) A recycling step, which includes a stage in which a portion of the hydrocarbon effluent obtained from separation step c) or a portion of the hydrocarbon stream obtained from fractionation step d) and / or at least one is recovered to the selective hydrogenation step a) and / or the hydrotreatment step b).

[0012] According to application FR 20 / 01758, the selective hydrogenation step a) and the hydrotreating step b) are independent steps, carried out under different conditions and in different reactors. Furthermore, according to application FR20 / 01758, the selective hydrogenation step a) is carried out under mild conditions, particularly at temperatures of 100-250°C, which leads to premature deactivation of the catalyst. Finally, according to application FR20 / 01758, the hydrotreating step b) is typically carried out at significantly higher temperatures than the selective hydrogenation step a), particularly at temperatures of 250-430°C, requiring heating equipment between the two steps.

[0013] Therefore, it would be advantageous to carry out the hydrogenation of dienes and a portion of the hydrogenation treatment reaction, especially a portion of the hydrogenation of olefins and a portion of the hydrogenation demetallization reaction (especially the retention of silicon), in the same step and at a temperature sufficient to limit catalyst deactivation.

[0014] This same step can also benefit from the heat of the hydrogenation reaction, especially the heat of hydrogenation of a portion of the dienes, resulting in a rising temperature profile in this step and thus eliminating the need for heating equipment between the hydrogenation catalytic section and the hydrogenation treatment catalytic section. Invention Overview

[0016] This invention relates to a method for processing raw materials containing plastic pyrolysis oil, comprising:

[0017] a) A hydrogenation step performed in a hydrogenation reaction section using at least one fixed-bed reactor comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrogenation catalyst, the hydrogenation reaction section being fed at least the feedstock and a gaseous stream containing hydrogen, the hydrogenation reaction section being maintained at an average temperature of 140-400°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 When used at a space velocity of , the outlet temperature of the reaction section in step a) is at least 15°C higher than the inlet temperature of the reaction section in step a) to obtain hydrogenated effluent.

[0018] b) A hydrotreating step using at least one fixed-bed reactor comprising n catalyst beds in a hydrotreating reaction section, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrotreating catalyst, the hydrotreating reaction section being fed at least the hydrotreating effluent obtained from step a) and a gaseous stream containing hydrogen, the hydrotreating reaction section being maintained at an average temperature of 250-430°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1When used at a space velocity of , the average temperature of the reaction section in step b) is higher than the average temperature of the hydrogenation reaction section in step a) in order to obtain the hydrogenation treatment effluent.

[0019] b′) Optionally, a hydrocracking step is performed in the hydrocracking reaction section using at least one fixed-bed hydrocracking step comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrocracking catalyst, the hydrocracking reaction section being fed at least the hydrotreated effluent obtained from step b) and / or a fraction containing compounds with a boiling point greater than 175°C obtained from step d) and a gaseous stream containing hydrogen, the hydrocracking reaction section being maintained at an average temperature of 250-450°C, a hydrogen partial pressure of 1.5-20.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 The space velocity is used to obtain hydrocracking effluent, which is then sent to separation step c);

[0020] c) A separation step, the feed of which is either the hydrotreated effluent obtained from step b) or the hydrocracking effluent obtained from step b') and an aqueous solution, the step being carried out at a temperature of 50-370°C to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent.

[0021] d) Optionally, a fractionation step of all or part of the hydrocarbon effluent obtained from step c) to obtain at least one gaseous effluent and at least one fraction containing a compound with a boiling point less than or equal to 175°C and at least one hydrocarbon fraction containing a compound with a boiling point greater than 175°C.

[0022] One advantage of the method according to the invention is the purification of at least a portion of the impurities in the oil obtained from the pyrolysis of plastic waste, which makes it possible to hydrogenate the oil and thus to modify it, particularly by incorporating it directly into a fuel storage unit or by making it compatible with processing in a steam cracking unit, thereby enabling the production of light olefins in particularly increased yields, which can be used as monomers in polymer manufacturing.

[0023] Another advantage of the present invention is that it prevents the risk of clogging and / or corrosion in the processing unit in which the method of the present invention is carried out, a risk exacerbated by the presence of dienes, metals and halogenated compounds in plastic pyrolysis oils.

[0024] Therefore, the method of the present invention enables the production of hydrocarbon effluents from plastic pyrolysis oil that are at least partially free of the impurities of the starting plastic pyrolysis oil, thus limiting operability issues such as corrosion, coking, or catalytic deactivation problems that these impurities can cause, particularly in steam cracking units and / or in units located downstream of the steam cracking unit, especially polymerization and hydrogenation units. Removing at least some of the impurities from the oil obtained from the pyrolysis of plastic waste also allows for an increased range of applications for the target polymers and reduced application incompatibilities.

[0025] According to one variation, the method includes step d).

[0026] According to one variation, the method includes step b′).

[0027] According to a variation, the amount of hydrogen-containing gaseous stream fed into the reaction section of step a) is such that the hydrogen coverage is 50-1000 Nm. 3 hydrogen / m 3 raw materials (Nm 3 / m 3 The preferred value is 200-300 Nm. 3 hydrogen / m 3 raw materials (Nm 3 / m 3 ).

[0028] According to a variation, the outlet temperature of step a) is at least 30°C higher than the inlet temperature of step a).

[0029] According to one variation, at least a portion of the hydrocarbon effluent obtained from separation step c) or at least a portion of the naphtha fraction containing compounds with a boiling point less than or equal to 175°C obtained from fractionation step d) is fed into hydrotreating step a) and / or hydrotreating step b).

[0030] According to one variation, at least a portion of the fraction obtained from fractionation step d) containing compounds with boiling points greater than 175°C is sent to hydrogenation step a) and / or hydrogenation treatment step b) and / or hydrocracking step b′).

[0031] According to one variant, the method includes a pretreatment step a0) of the feedstock containing plastic pyrolysis oil, the pretreatment step being carried out upstream of the hydrogenation step a) and including a filtration step and / or an electrostatic separation step and / or a washing step and / or an adsorption step using an aqueous solution.

[0032] According to one variation, all or part of the hydrocarbon effluent obtained from separation step c), or at least one of the two liquid hydrocarbon streams obtained from step d), is sent to steam cracking step e), which is carried out in at least one pyrolysis furnace at a temperature of 700-900°C and a relative pressure of 0.05-0.3 MPa.

[0033] According to one variation, the reaction section of step a) uses at least two reactors operating in a displaceable mode.

[0034] According to a variation, an amine-containing stream is injected upstream of step a).

[0035] According to one variant, the hydrogenation catalyst comprises a support selected from alumina, silica, silica-alumina, magnesium oxide, clay, and mixtures thereof, and a hydrogenation-dehydrogenation functional containing at least one Group VIII element and at least one Group VIB element, or containing at least one Group VIII element.

[0036] According to one variant, the hydrotreating catalyst comprises a support selected from alumina, silica, silica-alumina, magnesium oxide, clay, and mixtures thereof, and a hydrotreating-dehydrogenating functional compound containing at least one Group VIII element and / or at least one Group VIB element.

[0037] According to a variant, the method further includes a second hydrocracking step b″) in a hydrocracking reaction section using at least one fixed bed comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrocracking catalyst, the hydrocracking reaction section being fed with a fraction containing compounds with boiling points greater than 175°C obtained from step d) and a gaseous stream containing hydrogen, the hydrocracking reaction section being operated at a temperature of 250-450°C, a hydrogen partial pressure of 1.5-20.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 The process is carried out at a space-time velocity to obtain hydrocracking effluent, which is then sent to separation step c).

[0038] According to one variant, the hydrocracking catalyst comprises a combination of oxides of alumina halide, boron and aluminum, a support of amorphous silica-alumina and zeolite, and a hydro-dehydrogenation functional compound containing at least one Group VIB metal (alone or as a mixture) selected from chromium, molybdenum and tungsten and / or at least one Group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum.

[0039] The present invention also relates to products that can be obtained, preferably by means of the method according to the invention.

[0040] According to this variant, the product comprises, relative to the total weight of the product:

[0041] - Metallic elements with a total content of less than or equal to 5.0 ppm by weight;

[0042] -Iron with a content of less than or equal to 100 ppb by weight;

[0043] - Silicon element with a content of less than or equal to 1.0 ppm by weight;

[0044] - Sulfur content less than or equal to 500 ppm by weight;

[0045] - Nitrogen content less than or equal to 100 ppm by weight;

[0046] - Chlorine element with a content of less than or equal to 10 ppm by weight.

[0047] According to the present invention, unless otherwise stated, pressure is absolute pressure, also written as abs., and given in MPa absolute pressure (or MPaabs.).

[0048] According to the present invention, the expressions "included between..." and "...to..." are equivalent and mean that the limit of the interval is included within the range of said values. This description is given if this is not the case, and if the limit is not included within the range.

[0049] For the purposes of this invention, various ranges of parameters for a given step, such as pressure ranges and temperature ranges, can be used individually or in combination. For example, for the purposes of this invention, it is preferable that a range of pressure values ​​can be combined with a more preferred range of temperature values.

[0050] Specific and / or preferred embodiments of the invention may be described below. They may be implemented individually or in combination, where technically feasible, without limitation on the combination.

[0051] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by DRLide, 81st edition, 2000-2001). For example, Group VIII according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUPAC classification.

[0052] Metal content was measured by X-ray fluorescence method.

[0053] Detailed description

[0054] raw material

[0055] According to the invention, "plastic pyrolysis oil" is an oil that is advantageously liquid at ambient temperature, obtained from the pyrolysis of plastics, preferably plastic waste, particularly plastic waste from collection and sorting channels. It can also be obtained from the pyrolysis of worn-out tires.

[0056] It specifically comprises hydrocarbons, particularly alkanes, mono- and / or dienes, cycloalkanes, and aromatic compounds. At least 80% by weight of these hydrocarbons preferably have a boiling point below 700°C, more preferably below 550°C. Specifically, depending on the source of the pyrolysis oil, the oil contains up to 70% by weight of alkanes, up to 90% by weight of olefins, and up to 90% by weight of aromatic compounds; it should be understood that the sum of alkanes, olefins, and aromatic compounds equals 100% by weight of hydrocarbons.

[0057] The density of pyrolysis oil, measured at 15°C according to ASTM D4052 method, is typically 0.75-0.99 g / cm³. 3 The preferred value is 0.75-0.95 g / cm³. 3 .

[0058] Plastic pyrolysis oil may additionally contain, and typically does contain, impurities such as metals, particularly iron, silicon, or halogenated compounds, especially chlorinated compounds. These impurities can be present in high concentrations in plastic pyrolysis oil, for example, up to 350 ppm by weight or even 700 ppm by weight or even 1000 ppm by weight of halogenated elements (especially chlorine), and up to 100 ppm by weight or even 200 ppm by weight of metallic or semi-metallic elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals, and metalloids can be considered as metallic contaminants and are referred to as metals or metallic or semi-metallic elements. In particular, metals or metallic or semi-metallic elements that may be contained in oil obtained from the pyrolysis of plastic waste include silicon, iron, or both. Plastic pyrolysis oil may also contain other impurities, such as impurities particularly provided by sulfur compounds, oxygen compounds, and / or nitrogen compounds, typically in concentrations less than 10,000 ppm by weight, preferably less than 4,000 ppm by weight.

[0059] The raw materials for the method according to the invention comprise at least one type of plastic pyrolysis oil. The raw materials may consist solely of one or more types of plastic pyrolysis oil. Preferably, the raw materials comprise at least 50% by weight, preferably 70-100% by weight, of plastic pyrolysis oil relative to the total weight of the raw materials.

[0060] In addition to one or more plastic pyrolysis oils, the raw materials for the method according to the invention may include conventional petroleum-based raw materials or raw materials obtained from biomass conversion, which are then co-treated with the plastic pyrolysis oil of the raw materials.

[0061] Conventional petroleum-based feedstocks can advantageously be fractions of naphtha, gas oil, or vacuum gas oil types, or mixtures of these fractions.

[0062] The feedstock obtained from biomass conversion can advantageously be selected from vegetable oils, oils derived from algae or seaweed, fish oils, waste cooking oils, and fats of plant or animal origin, or mixtures of these feedstocks. The vegetable oils can advantageously be wholly or partially unprocessed or refined, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, coconut kernel, castor oil plant, cotton, peanut oil, flaxseed oil, and sea cabbage oil, as well as all oils derived through genetic modification or hybridization, such as from sunflower or rapeseed; this list is not limiting. The animal fats are advantageously selected from whale blubber and fats composed of residues from the food industry or fats derived from the catering industry. Frying oils and various animal fats, such as fish oil, tallow, or lard, can also be used.

[0063] Feedstocks obtained from biomass conversion can also be selected from feedstocks derived from biomass thermal or catalytic conversion methods, such as oils produced from biomass, particularly lignocellulosic biomass, using various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, including plants, animals, and their byproducts. The term "lignocellulosic biomass" refers to biomass derived from plants and their byproducts. Lignocellulosic biomass consists of carbohydrate polymers (cellulose, hemicellulose) and aromatic polymers (lignin).

[0064] The raw materials obtained from biomass conversion can also be advantageously selected from raw materials obtained from the paper industry.

[0065] Plastic pyrolysis oil can be obtained by thermocatalytic pyrolysis or by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0066] Preprocessing (optional)

[0067] The feedstock containing plastic pyrolysis oil can advantageously be pretreated in an optional pretreatment step a0) prior to the hydrogenation step a) to obtain a pretreated feedstock for feeding into step a).

[0068] The optional pretreatment step a0) allows for the reduction of the amount of contaminants that may be present in the raw material containing plastic pyrolysis oil, particularly the amount of iron and / or silicon and / or chlorine. Therefore, the optional pretreatment step a0) of the raw material containing plastic pyrolysis oil is advantageously carried out, particularly when the raw material contains more than 10 ppm by weight, particularly more than 20 ppm by weight, and more particularly more than 50 ppm by weight of metallic elements, and particularly when the raw material contains more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, or even more than 20 ppm by weight of silicon. Similarly, the optional pretreatment step a0) of the raw material containing plastic pyrolysis oil is advantageously carried out, particularly when the raw material contains more than 10 ppm by weight, particularly more than 20 ppm by weight, and more particularly more than 50 ppm by weight of chlorine.

[0069] The optional pretreatment step (a0) can be carried out by any method known to those skilled in the art for reducing the amount of contaminants. It may in particular include filtration and / or electrostatic separation and / or washing and / or adsorption steps using aqueous solutions.

[0070] The optional pretreatment step a0) is advantageously carried out at a temperature of 0-150°C, preferably 5-100°C, and a pressure of 0.15-10.0 MPa (absolute pressure), preferably 0.2-1.0 MPa (absolute pressure).

[0071] According to one variation, the optional pretreatment step a0) is carried out in an adsorption section having at least one specific surface area greater than or equal to 100 m². 2 / g, preferably greater than or equal to 200mg 2 The operation is carried out in the presence of an adsorbent of / g, preferably an alumina-type adsorbent. The specific surface area of ​​the at least one adsorbent is advantageously less than or equal to 600 m². 2 / g, especially less than or equal to 400mg 2 / g. 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 the standard ASTM D 3663-78 established by the Brunauer-Emmett-Teller method described in The Journal of the American Chemical Society, 60, 309 (1938).

[0072] Advantageously, the adsorbent contains less than 1% by weight of a metal element, and preferably contains no metal element. The term "metal element in the adsorbent" should be understood to refer to elements in groups 6-10 of the periodic table (new IUPAC classification). The residence time of the feedstock in the adsorption section is typically 1-180 minutes.

[0073] The adsorption section of optional step a0) comprises at least one adsorption tower containing the adsorbent, preferably at least two adsorption towers, and more preferably two to four adsorption towers. When the adsorption section comprises two adsorption towers, one operating mode can be a mode known in technical terms as “swing” operation, where one tower is online (i.e., in use) while the other tower is on standby. When the adsorbent in the online tower fails, that tower is isolated, while the standby tower is brought online (i.e., in use). The failed adsorbent can then be regenerated in situ and / or replaced with fresh adsorbent so that once the other tower is isolated, the tower containing it can be brought back online.

[0074] Another operating mode involves at least two towers operating in series. When the adsorbent in the top tower becomes ineffective, the first tower is isolated, and the ineffective adsorbent is regenerated in situ or replaced with fresh adsorbent. The tower is then returned to its last online position, and so on. This operating mode is called a displaceable mode, or PRS for displaceable reactor systems, or, according to specialized terminology, "lead and lag." The combination of at least two adsorption towers allows for overcoming the potential and possible rapid poisoning and / or clogging of the adsorbent due to the combined effects of metallic contaminants, dienes, gums derived from dienes, and insoluble substances that may be present in the pyrolysis oil of the plastics being treated. This is because the presence of at least two adsorption towers facilitates adsorbent replacement and / or regeneration, advantageously without stopping the pretreatment unit or even the method itself, thus reducing the risk of clogging and thereby avoiding unit downtime due to clogging, controlling costs, and limiting adsorbent consumption.

[0075] According to another variation, the optional pretreatment step a0) is carried out in a washing section using an aqueous solution, such as water or an acidic or alkaline solution. This washing section may include equipment for contacting the feedstock with the aqueous solution and equipment for separating the phases, so as to obtain a pretreated feedstock on the one hand and an aqueous solution containing impurities on the other. Such equipment may include, for example, stirred reactors, decanters, mixer-decanters, and / or co-current or counter-current washing towers.

[0076] The optional pretreatment step a0) may also optionally include a feed containing at least a portion of the recycled stream, which is advantageously obtained from step d) of the method, either as a mixture with or separately from the feed containing the plastic pyrolysis oil.

[0077] The optional pretreatment step a0) thus makes it possible to obtain a pretreated feedstock, which can then be fed into the hydrogenation step a).

[0078] Hydrogenation step a)

[0079] According to the present invention, the method includes a hydrogenation step a) in a hydrogenation reaction section using at least one fixed-bed reactor comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrogenation catalyst, the hydrogenation reaction section being fed at least the feedstock and a gaseous stream containing hydrogen, the hydrogenation reaction section being maintained at an average temperature of 140-400°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 When used at a space velocity of , the outlet temperature of the reaction section in step a) is at least 15°C higher than the inlet temperature of the reaction section in step a) to obtain hydrogenated effluent.

[0080] Step a) is carried out under hydrogen pressure and temperature conditions that allow for the hydrogenation of dienes and olefins at the start of the hydrogenation reaction section, while also allowing for a rising temperature profile, so that the outlet temperature of the reaction section in step a) is at least 15°C higher than the inlet temperature of the reaction section in step a). In fact, the required amount of hydrogen is injected to hydrogenate at least a portion of the dienes and olefins present in the plastic pyrolysis oil, to hydrogenate and demetallize at least a portion of the metals, especially the retention of silicon, and to achieve at least a portion of the chlorine conversion (to HCl). Therefore, the hydrogenation of dienes and olefins can avoid or at least limit the formation of “colloids,” i.e., the polymerization of dienes and olefins and the resulting formation of oligomers and polymers, which would clog the reaction section of the hydrogenation process in step b). Hydrometallization during hydrogenation, especially the retention of silicon during step a), can limit the catalytic deactivation of the hydrogenation reaction section in step b). Furthermore, the conditions of step a), especially the temperature and its rising profile, can convert at least a portion of the chlorine.

[0081] Therefore, temperature control is crucial in this step and must meet antagonistic constraints. On one hand, the temperature at the inlet and throughout the hydrogenation reaction section must be sufficiently low to allow hydrogenation of dienes and olefins at the start of the hydrogenation reaction section. On the other hand, the inlet temperature of the hydrogenation reaction section must be sufficiently high to avoid catalyst deactivation. Since the hydrogenation reaction, especially the hydrogenation of some olefins and dienes, is highly exothermic, a rising temperature profile is observed in the hydrogenation reaction section. The higher temperature at the end of this section allows for hydrodemetallization and hydrodechlorination reactions. Therefore, the outlet temperature of the reaction section in step a) is at least 15°C higher than the inlet temperature of the reaction section in step a), preferably at least 25°C higher, and particularly preferably at least 30°C higher.

[0082] The temperature difference between the inlet and outlet of the reaction section in step a) is compatible with the optional injection of any gaseous (hydrogen) cooling stream or liquid cooling stream (e.g., the recirculation of the stream generated from step c) and / or step d).

[0083] The temperature difference between the inlet and outlet of the reaction section in step a) is entirely due to the exothermic nature of the chemical reaction taking place in the reaction section, so there is no need to use heating means (oven, heat exchanger, etc.).

[0084] The inlet temperature of the reaction section in step a) is 135-385℃, preferably 210-335℃.

[0085] The outlet temperature of the reaction section in step a) is 150-400℃, preferably 225-350℃.

[0086] According to the invention, the hydrogenation of the diene and a portion of the hydrotreating reaction are advantageously carried out in the same step at a temperature sufficient to limit catalyst deactivation in step a), the deactivation manifested as a decrease in diene conversion. This same step can also benefit from the heat of the hydrogenation reaction, especially the heat of the hydrogenation reaction of the olefins and dienes, thus having an increasing temperature profile in this step, and therefore eliminating the need for heating equipment between the hydrogenation catalytic section and the hydrotreating catalytic section.

[0087] The reaction section, in the presence of at least one hydrogenation catalyst, is advantageously maintained at an average temperature (or WABT as defined below) of 140-400°C, preferably 220-350°C, particularly preferably 260-330°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), preferably 1.5-8.0 MPa (absolute pressure), and a duration of 0.1-10.0 h. -1 , preferably 0.2-5.0h -1 0.3-3.0h is the optimal value. -1 Hydrogenation is carried out at a space velocity (HSV).

[0088] According to the present invention, the “average temperature” of the reaction section corresponds to the weight-average bed temperature (WABT) according to specific terminology, which is well known to those skilled in the art. The average temperature is advantageously determined based on the catalytic system used, the equipment, and its configuration. The average temperature (or WABT) is calculated as follows:

[0089] WABT=(T 入口 +T 出口 ) / 2

[0090] Among them, T 入口 : The effluent temperature at the inlet of the reaction section, T 出口 Temperature of the effluent at the outlet of the reaction section.

[0091] Hourly space velocity (HSV) is defined herein as the ratio of the hourly volumetric flow rate of the feedstock (optionally pretreated) containing plastic pyrolysis oil to the volume of one or more catalysts.

[0092] Hydrogen coverage is defined as the ratio of the volumetric flow rate of hydrogen obtained under standard temperature and pressure conditions to the volumetric flow rate of "fresh" feedstock at 15°C (optionally pretreated) without considering any recirculation portion (in standard m³ / s). 3 (written as Nm) 3 H2 / m 3 (Unit: raw materials).

[0093] The amount of hydrogen (H2) gaseous stream fed into the reaction section of step a) is advantageously such that the hydrogen coverage is 50-1000 Nm. 3 hydrogen / m 3 raw materials (Nm 3 / m 3 The preferred value is 50-500 Nm. 3 hydrogen / m 3 raw materials (Nm 3 / m 3 The preferred value is 200-300 Nm. 3 hydrogen / m 3 raw materials (Nm 3 / m 3 In fact, the amount of hydrogen required to achieve at least a portion of the hydrogenation of dienes and olefins and at least a portion of the dehydrogenation and demetallization of metals (especially the retention of silicon) and also to achieve at least a portion of the conversion of chlorine (to HCl) is greater than the amount of hydrogen required to perform only the hydrogenation of dienes as described in FR20 / 01758.

[0094] The hydrogenation reaction section of step a) is fed at least with the feedstock comprising plastic pyrolysis oil, or feedstock obtained from the pretreatment of optional pretreatment step a0), and a gaseous stream comprising hydrogen (H2). Optionally, the reaction section of step a) may also be fed with at least a portion of the recycled stream advantageously obtained from step c) or optional step d).

[0095] Advantageously, the reaction section of step a) comprises 1-5 reactors, preferably 2-5 reactors, and particularly preferably two reactors. The advantage of a hydrogenation reaction section comprising several reactors is that it optimizes feedstock handling and reduces the risk of blockage of one or more catalyst beds, thereby preventing unit downtime due to blockage.

[0096] According to one variant, these reactors operate in a displaceable mode, also known as a displaceable reactor system (PRS), or "lead and lag." A combination of at least two reactors operating in PRS mode can isolate one reactor to drain the spent catalyst, refill the reactor with fresh catalyst, and reactivate the reactor without stopping the process. PRS technology is specifically described in patent FR2681871.

[0097] According to a particularly preferred variant, the hydrogenation reaction section of step a) comprises two reactors operating in a displaceable mode.

[0098] Advantageously, reactor inserts, such as filter plate type inserts, can be used to prevent clogging of one or more reactors. Examples of filter plates are described in patent FR3051375.

[0099] Advantageously, the hydrogenation catalyst includes a support, preferably a mineral support, and a hydrogenation-dehydrogenation functional compound.

[0100] According to one variant, the hydrotreating-dehydrogenating functional compound particularly comprises at least one Group VIII element, preferably selected from nickel and cobalt, and at least one Group VIB element, preferably selected from molybdenum and tungsten. According to this variant, the total content of oxides of metal elements from Group VIB and Group VIII, relative to the total weight of the catalyst, is preferably 1%-40% by weight, more preferably 5%-30% by weight. 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 one or more Group VIB metals (represented as metal oxides) to one or more Group VIII metals is preferably 1-20, more preferably 2-10.

[0102] According to this variant, the reaction section of step a) comprises, for example, a hydrogenation catalyst, which is contained in 0.5-12 wt% nickel, preferably 1-10 wt% nickel (expressed as nickel oxide NiO relative to the weight of the catalyst), and 1-30 wt% molybdenum, preferably 3-20 wt% molybdenum (expressed as molybdenum oxide MoO3 relative to the weight of the catalyst), on a support, preferably a mineral support, preferably an alumina support, and 1-30 wt% molybdenum.

[0103] According to another variant, the hydrodehydrogenation functional compound comprises at least one Group VIII element, preferably nickel, and is preferably composed of it. According to this variant, the nickel oxide content is preferably 1-50% by weight, more preferably 10-30% by weight, relative to the weight of the catalyst. Such catalysts are preferably used in their reduced form on a support, preferably a mineral support, and more preferably on an alumina support.

[0104] The support for the hydrogenation catalyst is preferably selected from alumina, silica, silica-alumina, magnesium oxide, clay, and mixtures thereof. The support may contain dopant compounds, particularly selected from boron oxide, especially boron trioxide, zirconium oxide, cerium dioxide, titanium oxide, oxides of phosphorus pentoxide, and mixtures of these oxides. Preferably, the hydrogenation catalyst comprises an alumina support, optionally doped with phosphorus and optionally doped with boron. When phosphorus pentoxide (P₂O₅) is present, its concentration is less than 10% by weight relative to the weight of alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. When boron trioxide (B₂O₃) is present, its concentration is less than 10% by weight relative to the weight of alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. The alumina used may be, for example, γ- or η-alumina.

[0105] The hydrogenation catalyst is, for example, in extrusion form.

[0106] Very preferably, in addition to the one or more hydrogenation catalysts described above, step a) may also use at least one hydrogenation catalyst for step a), which comprises less than 1 wt% nickel and at least 0.1 wt% nickel, preferably 0.5 wt%, in terms of nickel oxide (NiO) relative to the weight of the catalyst, on an alumina support, and less than 5 wt% molybdenum and at least 0.1 wt% molybdenum, preferably 0.5 wt%, in terms of molybdenum oxide (MoO3) relative to the weight of the catalyst. This catalyst with a small amount of metal supported may preferably be placed upstream or downstream of the one or more hydrogenation catalysts described above.

[0107] The hydrogenation step a) yields a hydrogenated effluent, i.e., an effluent with reduced content of olefins (especially dienes) and metals (especially silicon). The content of impurities (especially dienes) in the hydrogenated effluent obtained at the end of step a) is reduced relative to the content of the same impurities (especially dienes) contained in the feedstock of the method. The hydrogenation step a) typically converts at least 40%, preferably at least 60%, of the dienes and at least 40%, preferably at least 60%, of the olefins contained in the initial feedstock. Step a) can also at least partially remove other contaminants, such as silicon and chlorine. Preferably, during step a), at least 50%, more preferably at least 75%, of the chlorine and silicon in the initial feedstock is removed. The hydrogenated effluent obtained at the end of the hydrogenation step a) is sent, preferably directly, to the hydrogenation treatment step b).

[0108] Hydrogenation treatment step b)

[0109] According to the present invention, the processing method includes a hydrotreating step b) in a hydrotreating reaction section using at least one fixed-bed reactor comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrotreating catalyst, the hydrotreating reaction section being fed at least the hydrotreating effluent obtained from step a) and a gaseous stream containing hydrogen, the hydrotreating reaction section being maintained at an average temperature of 250-430°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 When used at a space velocity of , the average temperature of the reaction section in step b) is higher than the average temperature of the hydrogenation reaction section in step a) to obtain the hydrogenation treatment effluent.

[0110] Advantageously, step b) carries out hydrogenation treatment reactions known to those skilled in the art, particularly hydrogenation treatment reactions such as hydrogenation of aromatic compounds, hydrodesulfurization, and hydrodenitrogenation. Furthermore, hydrogenation of olefins and hydrogenation of the remaining halogenated compounds, as well as hydrodemetallization, continue.

[0111] The hydrogenation treatment reaction section is advantageously carried out at a pressure equal to that used in the reaction section of hydrogenation step a), but at a higher average temperature than that used in the reaction section of hydrogenation step a). Therefore, the hydrogenation treatment reaction section is advantageously carried out at an average hydrogenation treatment temperature of 250-430°C, preferably 280-380°C, a hydrogen partial pressure of 1.0-10.0 MPa (absolute pressure), and a hydrogen per hour (Hb) of 0.1-10.0 h. -1 0.1-5.0h is preferred. -1 0.2-2.0h is preferred. -1 , preferably 0.2-1h -1 The procedure is carried out at a spacetime velocity (HSV). The hydrogen coverage in step b) is advantageously 50-1000 Nm. 3 hydrogen / m 3 The feed to the fresh raw material in step a) is preferably 50-500 Nm 3 hydrogen / m 3 The feed to the fresh raw material in step a) is preferably 100-300 Nm 3 hydrogen / m 3 The feed is added to the fresh feedstock in step a). The definitions of average temperature (WABT), HSV, and hydrogen coverage are consistent with those above.

[0112] The hydrotreating reaction section is fed at least with the hydrotreating effluent obtained from step a) and a gaseous stream containing hydrogen, which advantageously enters the first catalytic bed of the first functional reactor. Optionally, the reaction section of step b) may also be fed with at least a portion of the recycled stream advantageously obtained from step c) or optionally step d).

[0113] Advantageously, step b) is carried out in a hydrotreatment reaction section comprising at least one, preferably one to five, fixed-bed reactors comprising n catalyst beds, where n is an integer greater than or equal to one, preferably one to ten, preferably two to five, and each of the one or more beds contains at least one, preferably no more than ten, hydrotreatment catalysts. When the reactor comprises several catalyst beds, i.e., at least two, preferably two to ten, preferably two to five catalyst beds, the catalyst beds are preferably arranged in series in the reactor.

[0114] When step b) is carried out in a hydrotreating reaction section comprising several reactors, preferably two reactors, these reactors may be operated in series and / or in parallel and / or in a displaceable (or PRS) mode and / or a switching mode. Various optional operating modes, PRS (or lead and lag) modes, and switching modes are well known to those skilled in the art and are advantageously defined above.

[0115] In another embodiment of the invention, the hydrogenation treatment reaction section comprises a single fixed-bed reactor comprising n catalyst beds, where n is an integer greater than or equal to 1, preferably 1-10, and more preferably 2-5.

[0116] In a particularly preferred embodiment, the hydrogenation reaction section of step a) comprises two reactors operating in a displaceable mode, followed by the hydrogenation treatment reaction section of step b) comprising a single fixed-bed reactor.

[0117] Advantageously, the hydrotreating catalyst used in step b) can be selected from known hydrodemetallization, hydrotreating, or silicon removal catalysts, particularly catalysts for treating petroleum fractions, and combinations thereof. Known hydrodemetallization catalysts are, for example, those described in patents EP 0113297, EP 0113284, US 5221656, US 5827421, US7119045, US 5622616, and US 5089463. Known hydrotreating catalysts are, for example, those described in patents EP0113297, EP 0113284, US 6589908, US 4818743, or US 6332976. Known silicon removal catalysts are, for example, those described in patent applications CN 102051202 and US 2007 / 080099.

[0118] Specifically, the hydrotreating catalyst comprises a support, preferably a mineral support, and at least one metallic element with hydrodehydrogenation function. The metallic element with hydrodehydrogenation function advantageously comprises at least one Group VIII element, preferably selected from nickel and cobalt, and / or at least one Group VIB element, preferably selected from molybdenum and tungsten. The total content of oxides of Group VIB and Group VIII metallic elements relative to the total weight of the catalyst is preferably from 0.1% to 40% by weight, more preferably from 5% to 35% by weight. 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 one or more Group VIB metals, expressed as metal oxides, to one or more Group VIII metals is preferably from 1.0 to 20, more preferably from 2.0 to 10. For example, the hydrotreating reaction section of step b) of the method comprises a hydrotreating catalyst, which is contained on a mineral support, preferably on an alumina support, of 0.5% to 10% by weight of nickel (NiO) relative to the total weight of the hydrotreating catalyst, preferably 1% to 8% by weight of nickel, and of 1.0% to 30% by weight of molybdenum (MoO3) relative to the total weight of the hydrotreating catalyst, preferably 3.0% to 29% by weight of molybdenum.

[0119] The support for the hydrotreating catalyst is advantageously selected from alumina, silica, silica-alumina, magnesium oxide, clay, and mixtures thereof. The support may also contain dopant compounds, particularly selected from boron oxide, especially boron trioxide, zirconium oxide, cerium dioxide, titanium oxide, oxides of phosphorus pentoxide, and mixtures of these oxides. Preferably, the hydrotreating catalyst comprises an alumina support, preferably an alumina support doped with phosphorus and optionally boron. When phosphorus pentoxide (P₂O₅) is present, its concentration is less than 10% by weight relative to the weight of alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. When boron trioxide (B₂O₃) is present, its concentration is less than 10% by weight relative to the weight of alumina, and advantageously at least 0.001% by weight relative to the total weight of alumina. The alumina used may be, for example, γ- or η-alumina.

[0120] The hydrogenation catalyst is, for example, in extrusion form.

[0121] Advantageously, the hydrotreating catalyst used in step b) of the method has a concentration greater than or equal to 250 m 2 / g, preferably greater than or equal to 300mg 2 The specific surface area of ​​the hydrotreating catalyst is advantageously less than or equal to 800 m² / g. 2 / g, preferably less than or equal to 600m 2 / g, especially less than or equal to 400mg2 / g. The specific surface area of ​​the hydrotreating catalyst was measured by the BET method, i.e., the specific surface area determined by nitrogen adsorption according to the standard ASTM D 3663-78 established by the Brunauer-Emmett-Teller method described in The Journal of the American Chemical Society, 60, 309 (1938). This specific surface area allows for further improvement in the removal of contaminants, particularly metals such as silicon.

[0122] According to another aspect of the invention, the hydrogenation catalyst described above further comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are generally referred to by the term "catalyst with additives." Typically, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxyl, 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.

[0123] Advantageously, the hydrotreating step b) can hydrogenate at least 80%, preferably all, of the olefins remaining after the hydrotreating step a), and can also at least partially convert 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 10 ppm by weight. Step b) can further reduce the content of contaminants, such as metals, especially silicon. Preferably, the metal content 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.

[0124] Hydrocracking step b′ (optional)

[0125] According to one variation, the method of the present invention may include a hydrocracking step b'), which is performed directly after the hydrotreating step b) or after the fractionation step d) on a hydrocarbon fraction (diesel fraction) containing compounds with a boiling point greater than 175°C.

[0126] Advantageously, step b') performs a hydrocracking reaction known to those skilled in the art, particularly converting heavy compounds, such as those with boiling points greater than 175°C, into compounds with boiling points less than or equal to 175°C, said heavy compounds being contained in the hydrotreatment effluent obtained from step b) or separated during fractionation step d). Other reactions may then be carried out, such as hydrogenation of olefins or aromatic compounds, hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, etc.

[0127] Compounds with boiling points above 175°C have high BMCI and contain more cycloalkanes, cycloalkanes-aromatics, and aromatics compared to lighter compounds, resulting in a higher C / H ratio. This high ratio is a cause of coking in steam crackers, thus requiring steam crackers specifically designed for this fraction. When it is desirable to minimize the yield of these heavy compounds (diesel fractions) and maximize the yield of light compounds (naphtha fractions), these compounds can be at least partially converted to light compounds via hydrocracking, which are typically favorable fractions for steam cracking units.

[0128] Therefore, the method of the present invention may include a hydrocracking step b') in a hydrocracking reaction section using at least one fixed bed comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrocracking catalyst, the hydrocracking reaction section being fed with the hydrotreated effluent obtained from step b) and / or a fraction containing compounds with boiling points greater than 175°C obtained from step d) and a gaseous stream containing hydrogen, the hydrocracking reaction section being used at an average temperature of 250-450°C, a hydrogen partial pressure of 1.5-20.0 MPa (absolute pressure), and a space velocity of 0.1-10.0 h⁻¹ to obtain a hydrocracking effluent, which is then sent to the fractionation step d).

[0129] Therefore, the hydrocracking reaction section is advantageously characterized by an average temperature of 250-480°C, preferably 320-450°C, a hydrogen partial pressure of 1.5-20.0 MPa (absolute pressure), preferably 2-18.0 MPa (absolute pressure), and a hydrogen per hour concentration of 0.1-10.0 h. -1 0.1-5.0h is preferred. -1 , preferably 0.2-4h -1 The procedure is carried out at a spacetime velocity (HSV). The hydrogen coverage in step c) is advantageously 80-2000 Nm. 3 hydrogen / m 3 The feed to the fresh raw material in step a) is preferably 200-1800 Nm. 3 hydrogen / m 3 The feed is added to the fresh feedstock in step a). The definitions of average temperature (WABT), HSV, and hydrogen coverage are consistent with those above.

[0130] Advantageously, the hydrocracking reaction section is carried out at a pressure equal to that used in the reaction section of the hydrocracking step a) or the hydrotreatment step b).

[0131] Advantageously, step b') is carried out in a hydrocracking reaction section comprising at least one, preferably one to five, fixed-bed reactors comprising n catalyst beds, where n is an integer greater than or equal to one, preferably one to ten, preferably two to five, and each of the one or more beds contains at least one, preferably no more than ten, hydrocracking catalysts. When the reactor comprises several catalyst beds, i.e., at least two, preferably two to ten, preferably two to five catalyst beds, the catalyst beds are preferably arranged in series in the reactor.

[0132] The hydrotreatment step b) and the hydrocracking step b') can advantageously be carried out in the same reactor or in different reactors. When they are carried out in the same reactor, the reactor comprises several catalyst beds, the first catalyst bed containing one or more hydrotreatment catalysts, and subsequent catalyst beds containing one or more hydrocracking catalysts.

[0133] The hydrocracking step can be carried out in one step (step b′) or two steps (step b′ and step b″). When carried out in two steps, the effluent obtained from the first hydrocracking step b′) is separated to obtain a fraction (diesel fraction) containing compounds with a boiling point greater than 175°C during steps c) and d). This fraction is introduced into the second hydrocracking step b″), which includes a dedicated second hydrocracking reaction section different from the first hydrocracking reaction section b′). This configuration is particularly suitable when it is desired to produce only naphtha fractions.

[0134] The second hydrocracking step b″) is carried out in a hydrocracking reaction section using at least one fixed bed comprising n catalyst beds, where n is an integer greater than or equal to 1. Each catalyst bed contains at least one hydrocracking catalyst. The hydrocracking reaction section is fed at least a fraction containing compounds with a boiling point greater than 175°C obtained from step d) and a gaseous stream containing hydrogen. The hydrocracking reaction section is maintained at an average temperature of 250-450°C, a hydrogen partial pressure of 1.5-20.0 MPa (absolute pressure), and a h⁻¹ of 0.1-10.0 h⁻¹. -1 The hydrocracking process is carried out at a specific space velocity to obtain the hydrocracking effluent, which is then sent to separation step c). The preferred operating conditions and catalyst used in the second hydrocracking step are those described for the first hydrocracking step. The operating conditions and catalysts used in the two hydrocracking steps may be the same or different.

[0135] The second hydrocracking step is preferably carried out in a hydrocracking reaction section comprising at least one, preferably one to five, fixed-bed reactors comprising n catalyst beds, where n is an integer greater than or equal to 1, preferably 1-10, and more preferably 2-5, and each of the one or more beds comprises at least one, preferably no more than ten, hydrocracking catalysts.

[0136] These operating conditions used in one or more hydrocracking steps typically yield a single-pass conversion of greater than 15 wt% and even more preferably 20 wt% to 95 wt% to a product having a boiling point less than or equal to 175 °C, preferably less than 160 °C, and more preferably less than 150 °C. When the method is carried out in two hydrocracking steps, the single-pass conversion of the second step is kept moderate to maximize selectivity for naphtha fraction compounds (boiling point less than or equal to 175 °C, particularly 80 °C to less than or equal to 175 °C). The single-pass conversion is limited by using a high recycling ratio throughout the second hydrocracking step loop. This ratio is defined as the ratio of the feed flow rate of step b″) to the feed flow rate of step a); preferably, this ratio is 0.2-4, more preferably 0.5-2.5.

[0137] Therefore, one or more hydrocracking steps may not necessarily convert all compounds with boiling points greater than 175°C (diesel fraction) into compounds with boiling points less than or equal to 175°C (naphtha fraction). Thus, after fractionation step d), there may still be a more or less significant proportion of compounds with boiling points greater than 175°C. To improve conversion, at least a portion of this unconverted fraction can be recycled to step b′), as described below, or it can be fed into a second hydrocracking step b″). Another portion can be purged. Depending on the operating conditions of the method, the purged fraction may be 0-10 wt%, preferably 0.5 wt%-5 wt%, of a fraction containing compounds with boiling points greater than 175°C relative to the incoming feedstock.

[0138] According to the present invention, one or more hydrocracking steps are carried out in the presence of at least one hydrocracking catalyst.

[0139] One or more hydrocracking catalysts used in one or more hydrocracking steps are conventional hydrocracking catalysts known to those skilled in the art, and are bifunctional types combining acid functionality and hydrocracking-dehydrogenation functionality with optionally at least one binder matrix. The acid functionality is characterized by a large surface area (typically 150-800 m²) exhibiting surface acidity. 2 The support is provided (e.g., / g), such as halogenated (especially chlorinated or fluorinated) alumina, combinations of boron and aluminum oxides, amorphous silica-alumina, and zeolites. The hydrogenation-dehydrogenation function is provided by at least one metal of Group VIB and / or at least one metal of Group VIII of the periodic table.

[0140] Preferably, one or more hydrocracking catalysts comprise a hydro-dehydrogenation functionalist containing at least one Group VIII metal selected from iron, cobalt, nickel, ruthenium, rhodium, palladium, and platinum, preferably cobalt and nickel. Preferably, the one or more catalysts further comprise at least one Group VIB metal selected from chromium, molybdenum, and tungsten, alone or in a mixture, and preferably molybdenum and tungsten. Hydro-dehydrogenation functionalists of the NiMo, NiMoW, or NiW type are preferred.

[0141] Preferably, the content of a Group VIII metal in one or more hydrocracking catalysts is advantageously 0.5-15% by weight, more preferably 1-10% by weight, said percentage being expressed as a weight percentage of oxides 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.

[0142] Preferably, the content of a Group VIB metal in one or more hydrocracking catalysts is advantageously 5-35% by weight, more preferably 10-30% by weight, said percentage being expressed as a weight percentage of oxides 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.

[0143] One or more hydrocracking catalysts may also optionally contain at least one co-catalyst element deposited on the catalyst, selected from phosphorus, boron and silicon, optionally at least one Group VIIA element (preferably chlorine and fluorine), optionally at least one Group VIIB element (preferably manganese), and optionally at least one Group VB element (preferably niobium).

[0144] Preferably, one or more hydrocracking catalysts comprise at least one oxide-type amorphous or poorly crystalline porous mineral matrix selected from alumina, silica, silica-alumina, aluminates, alumina-boron oxide, magnesium oxide, silica-magnesium oxide, zirconium oxide, titanium oxide, or clay, alone or in mixtures, and preferably alumina or silica-alumina, alone or in mixtures.

[0145] Preferably, the silica-alumina contains more than 50% by weight of alumina, and more preferably more than 60% by weight of alumina.

[0146] Preferably, one or more hydrocracking catalysts also optionally comprise a zeolite selected from Y zeolite, preferably USY zeolite, alone or in combination with other zeolites selected from β, ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 or ZBM-30 zeolites (alone or in mixtures). Preferably, the zeolite is USY zeolite alone.

[0147] When the catalyst contains zeolite, the zeolite content in one or more hydrocracking catalysts is advantageously 0.1-80% by weight, preferably 3-70% by weight, and the percentage is expressed as a percentage of zeolite relative to the total weight of the catalyst.

[0148] The preferred catalyst comprises at least one Group VIB metal and optionally at least one Group VIII non-precious metal, at least one co-catalyst element, preferably phosphorus, at least one Y zeolite and at least one alumina binder, and is preferably composed thereof.

[0149] Even more preferred catalysts include, and preferably consist of, nickel, molybdenum, phosphorus, USY zeolite and optional β zeolite and alumina.

[0150] Another preferred catalyst comprises, and preferably consists of, nickel, tungsten, alumina and silica-alumina.

[0151] Another preferred catalyst comprises, and preferably consists of, nickel, tungsten, USY zeolite, alumina and silica-alumina.

[0152] The hydrocracking catalyst is, for example, in extrusion form.

[0153] In one variant, the hydrocracking catalyst used in step b″) comprises a hydrodehydrogenation functionalist containing at least one noble metal from Group VIII, selected from palladium and platinum, either alone or as a mixture. The content of the noble metal from Group VIII is advantageously 0.01% to 5% by weight, preferably 0.05% to 3% by weight, expressed as a weight percentage of oxides (PtO or PdO) relative to the total weight of the catalyst.

[0154] According to another aspect of the invention, the hydrocracking catalyst described above further comprises one or more organic compounds containing oxygen and / or nitrogen and / or sulfur. Such catalysts are generally referred to by the term "catalyst with additives." Typically, the organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxyl, 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.

[0155] The preparation of catalysts in steps a), b), b′), or b″) is known and typically involves impregnating a Group VIII and Group VIB metal (if present) and optionally phosphorus and / or boron onto a support, followed by drying and then optionally calcination. In the case of catalysts with additives, preparation is usually carried out by simple drying without calcination after the introduction of the organic compound. The term "calcination" herein refers to heat treatment in a gas containing air or oxygen at a temperature greater than or equal to 200°C. The catalyst is typically sulfided to form the active material before being used in the process steps. The catalyst in step a) can also be a catalyst used in its reduced form, thus involving a reduction step in its preparation.

[0156] The hydrogen-containing gaseous stream fed into the reaction section of steps a), b), b′), or b″) can consist of a hydrogen supply and / or specifically obtained from the recycled hydrogen from the separation step c). Preferably, additional hydrogen-containing gaseous streams are advantageously introduced into the inlet of each reactor, particularly each reactor operating in series, and / or from the inlet of each catalyst bed in the second catalyst bed of the reaction section. These additional gaseous streams are also referred to as cooling streams. They can control the temperature in the reactors where the reactions involved are typically highly exothermic.

[0157] Optionally, each of steps a), b), b′), or b″) may use a heating section located upstream of the reaction section, in which the incoming effluent is heated to a suitable temperature. Thus, the optional heating section may include one or more heat exchangers, preferably capable of facilitating heat exchange between the hydrotreatment effluent and the hydrocracking effluent, and / or a preheating furnace.

[0158] However, implementing step a) at a relatively high average temperature with an upward curve can optionally eliminate the need for heating equipment, or at least reduce the heat requirements between the hydrogenation catalytic section of step a) and the hydrogenation treatment catalytic section of step b).

[0159] Separation step c)

[0160] According to the invention, the processing method includes a separation step c), which is advantageously carried out in at least one washing / separation section fed with at least the hydrotreated effluent obtained from step b), or the hydrocracking effluent obtained from optional steps b′) and b″), and an aqueous solution, to obtain at least one gaseous effluent, an aqueous effluent, and a hydrocarbon effluent.

[0161] The gaseous effluent obtained at the end of step c) advantageously contains hydrogen, preferably at least 80% by volume, more preferably at least 85% by volume. Advantageously, the gaseous effluent can be recycled at least partially to hydrogenation step a) and / or hydrotreatment step b) and / or hydrocracking step b') and / or hydrocracking step b''), and the recycling system may include a purification section.

[0162] The aqueous effluent obtained at the end of step c) advantageously contains ammonium salts and / or hydrochloric acid.

[0163] This separation step c) specifically allows for the removal of ammonium chloride salts formed through a reaction between chloride ions released during steps a) and b) by hydrogenation of a chlorinating compound, particularly in the form of HCl, followed by dissolution in water, and ammonium ions generated during step b) by hydrogenation of a nitrogen-containing compound, particularly in the form of NH3, and / or by injection of an amine, followed by dissolution in water. This limits the risk of blockage due to ammonium chloride precipitation, particularly in the delivery lines and / or in sections of the method of the invention and / or in the delivery lines of the steam cracker. It also allows for the removal of hydrochloric acid formed by the reaction of hydrogen and chloride ions.

[0164] Depending on the content of chloride compounds in the initial feedstock to be treated, a stream containing amines, such as monoethanolamine, diethanolamine, and / or monodiethanolamine, may be injected upstream of hydrogenation step a) and / or between hydrogenation step a) and hydrotreatment step b) and / or between hydrocracking step b') and separation step c), preferably upstream of hydrogenation step a). This ensures that a sufficient amount of ammonium ions combine with chloride ions formed during the hydrotreatment step, thereby limiting the formation of hydrochloric acid and thus limiting corrosion downstream of the separation section.

[0165] Advantageously, separation step c) includes injecting an aqueous solution, preferably water, upstream of the washing / separation section into the hydrotreated effluent obtained from step b) or the hydrocracking effluent obtained from optional steps b′) and b″) to at least partially dissolve ammonium chloride salts and / or hydrochloric acid, thereby improving the removal of chlorinated impurities and reducing the risk of blockage caused by the accumulation of ammonium chloride salts.

[0166] Separation step c) is advantageously carried out at a temperature of 50-450°C, preferably 100-440°C, and more preferably 200-420°C. It is important to conduct the step within this temperature range (therefore, the hydroconversion effluent is not excessively cooled), which carries the risk of clogging the pipeline due to the precipitation of ammonium chloride. Advantageously, separation step c) is carried out at a pressure close to that used in steps a) and / or b), preferably 1.0-20.0 MPa, to facilitate hydrogen recirculation.

[0167] The washing / separation section of step c) can be carried out at least in part in a common or separate washing and separation unit, which is known (separation vessel, pump, heat exchanger, washing tower, etc. that can operate at various pressures and temperatures).

[0168] In an optional embodiment of the invention, separation step c) comprises injecting an aqueous solution into the hydrotreated effluent obtained from step b), followed by a washing / separation section that advantageously includes a separation stage for obtaining at least one aqueous effluent carrying an ammonium salt, a washed hydrocarbon liquid effluent, and a partially washed gaseous effluent. The aqueous effluent carrying the ammonium salt and the washed hydrocarbon liquid effluent can then be separated in a decanting vessel to obtain the hydrocarbon effluent and the aqueous effluent. The partially washed gaseous effluent can be introduced in parallel into a washing tower, in which it circulates countercurrently relative to the aqueous stream, which preferably has the same properties as the aqueous solution injected into the hydrotreated effluent. This allows for at least partial, preferably complete, removal of hydrochloric acid contained in the partially washed gaseous effluent, thus obtaining the gaseous effluent preferably substantially containing hydrogen and the acidic aqueous stream. The aqueous effluent obtained from the decanting vessel may optionally be mixed with the acidic aqueous stream and optionally used as a mixture with the acidic aqueous stream in a water recirculation loop to feed the aqueous stream into the aqueous solution and / or washing tower upstream of the washing / separation section at separation step c). The water recirculation loop may include the supply of water and / or alkaline solution and / or the discharge for the removal of dissolved salts.

[0169] In another optional embodiment of the invention, separation step c) may advantageously include a “high-pressure” washing / separation section, which operates at pressures close to those of hydrogenation step a) and / or hydrogenation treatment step b) and / or optional hydrocracking step b′), preferably at 1.0-20.0 MPa, to facilitate hydrogen recycling. This optional “high-pressure” section of step c) may include a “low-pressure” section to obtain a hydrocarbon liquid fraction free of some of the gas dissolved at high pressure, and this hydrocarbon liquid fraction is intended to be processed directly in a steam cracking process or optionally fed to fractionation step d).

[0170] One or more gas fractions obtained from separation step c) may be subjected to one or more additional purifications and one or more separations to recover at least one hydrogen-rich gas (which may be recycled upstream of steps a) and / or b) and / or b′) and / or b″) and / or light hydrocarbons (particularly ethane, propane and butane), which may be advantageously fed alone or as a mixture to one or more furnaces in steam cracking step e) to increase the overall yield of olefins.

[0171] The hydrocarbon effluent obtained from separation step c) is partially or entirely fed directly to the inlet of the steam cracking unit, or to an optional fractionation step d). Preferably, the hydrocarbon liquid effluent is partially or entirely, preferably entirely, fed to fractionation step d).

[0172] Fractionation step d) (optional)

[0173] The method according to the invention may include the step of fractionating all or part, preferably all, of the hydrocarbon effluent obtained from step c) to obtain at least one gaseous stream and at least two hydrocarbon liquid streams, wherein the two hydrocarbon liquid streams are at least one naphtha fraction containing a compound with a boiling point less than or equal to 175°C, particularly 80-175°C, and one hydrocarbon fraction containing a compound with a boiling point greater than 175°C.

[0174] Step d) can in particular remove gases dissolved in hydrocarbon liquid effluents, such as ammonia, hydrogen sulfide and light hydrocarbons containing 1-4 carbon atoms.

[0175] The optional fractionation step d) is advantageously carried out at a pressure less than or equal to 1.0 MPa absolute pressure, preferably 0.1-1.0 MPa absolute pressure.

[0176] According to one embodiment, step d) can be carried out in a section that advantageously includes at least one stripping tower equipped with a reflux loop including a reflux container. The stripping tower is fed with a hydrocarbon liquid effluent and a vapor stream obtained from step c). The hydrocarbon liquid effluent obtained from step c) may optionally be heated before entering the stripping tower. Thus, the lightest compounds are entrained to the top of the tower and enter the reflux loop including the reflux container, where gas / liquid separation occurs. The gas phase containing light hydrocarbons is withdrawn from the reflux container as a gaseous stream. Advantageously, a naphtha fraction containing compounds with a boiling point less than or equal to 175°C is withdrawn from the reflux container. Advantageously, a hydrocarbon fraction containing compounds with a boiling point greater than 175°C is withdrawn from the bottom of the stripping tower.

[0177] According to other implementations, fractionation step d) may include a stripping column, followed by a distillation column, or may only include a distillation column.

[0178] Optionally mixed naphtha fractions containing compounds with boiling points less than or equal to 175°C and fractions containing compounds with boiling points greater than 175°C can be sent, in whole or in part, to a steam cracking unit, where olefins can be (re)formed at the unit's outlet to participate in polymer formation. Preferably, only a portion of the fractions is sent to the steam cracking unit; at least a portion of the remaining fraction is optionally recycled to at least one step of the method and / or sent to a fuel storage unit, such as a naphtha storage unit, diesel storage unit, or kerosene storage unit, which is derived from conventional petroleum-based feedstocks.

[0179] According to a preferred embodiment, all or part of the naphtha fraction containing compounds with a boiling point less than or equal to 175°C is sent to a steam cracking unit, while the fraction containing compounds with a boiling point greater than 175°C is recycled to steps a) and / or b) and / or b′), and / or sent to a fuel storage unit.

[0180] In one specific embodiment, optional fractionation step d) may result in, in addition to the gas stream, a naphtha fraction containing compounds with a boiling point less than or equal to 175°C, preferably 80-175°C, an intermediate distillate fraction containing compounds with a boiling point greater than 175°C and less than 385°C, and a hydrocarbon fraction (referred to as the heavy hydrocarbon fraction) containing compounds with a boiling point greater than or equal to 385°C. The naphtha fraction may be fed, in whole or in part, into a steam cracking unit and / or a naphtha storage unit obtained from conventional petroleum-based feedstocks, or may be recycled; the intermediate distillate fraction may be fed, in whole or in part, into a steam cracking unit or a diesel storage unit obtained from conventional petroleum-based feedstocks, or may be recycled; the heavy fraction itself may be fed, in at least part, into a steam cracking unit, or may be recycled.

[0181] In another specific embodiment, the optional fractionation step e) may, in addition to the gas stream, yield a naphtha fraction containing compounds with a boiling point less than or equal to 175°C, preferably 80-175°C; a kerosene fraction containing compounds with a boiling point greater than 175°C and less than or equal to 280°C; a diesel fraction containing compounds with a boiling point greater than 280°C and less than 385°C; and a hydrocarbon fraction containing compounds with a boiling point greater than or equal to 385°C (referred to as the heavy hydrocarbon fraction). The naphtha fraction may be fed, in whole or in part, to a steam cracking unit and / or a naphtha pool obtained from conventional petroleum-based feedstock, or to a recycling step g); the kerosene fraction and / or diesel fraction may be fed, in whole or in part, to a steam cracking unit or a kerosene or diesel pool obtained from conventional petroleum-based feedstock, or to a recycling step f); the heavy fraction itself may be fed, at least in part, to a steam cracking unit, or may be fed to a recycling step f).

[0182] In another specific embodiment, the naphtha fraction obtained from step d) containing compounds with a boiling point less than or equal to 175°C is fractionated into a heavy naphtha fraction containing compounds with a boiling point of 80-175°C and a light naphtha fraction containing compounds with a boiling point less than 80°C. At least a portion of the heavy naphtha fraction is fed into an aromatic complex including at least one naphtha reforming step to produce aromatic compounds. According to this embodiment, at least a portion of the light naphtha fraction is fed into the steam cracking step e) described below.

[0183] One or more gas fractions obtained from fractionation step d) may undergo additional purification and separation to recover at least light hydrocarbons, particularly ethane, propane and butane, which may be advantageously fed, alone or as a mixture, into a furnace of steam cracking step e) to increase the overall yield of olefins.

[0184] Recycling of fractions containing compounds with boiling points greater than 175°C

[0185] At least a portion of the fraction obtained from fractionation step d) containing compounds with boiling points greater than 175°C can be recycled to form a recycle stream, which can be fed upstream of at least one reaction step of the method according to the invention or directly into at least one reaction step of the method according to the invention, particularly into hydrogenation step a) and / or hydrotreatment step b) and / or hydrocracking step b'). Optionally, a portion of the recycle stream can be fed into optional step a0).

[0186] The recycle stream can be fed into reaction steps a) and / or b) and / or b′) in a single injection, or it can be divided into several parts and fed into reaction steps a) and / or b) and / or b′ in several injections, i.e., fed into different catalyst beds.

[0187] Advantageously, the amount of the recirculated stream containing the fraction of compounds with a boiling point greater than 175°C is adjusted such that the weight ratio of the recirculated stream to the feedstock containing the plastic pyrolysis oil, i.e., the feedstock to be processed throughout the process, is less than or equal to 10, preferably less than or equal to 5, and preferably greater than or equal to 0.001, more preferably greater than or equal to 0.01, and more preferably greater than or equal to 0.1. Very preferably, the amount of the recirculated stream is adjusted such that the weight ratio of the recirculated stream to the feedstock containing the plastic pyrolysis oil is 0.2-5.

[0188] According to a preferred variant, at least a portion of the fraction obtained from fractionation step d) containing compounds with boiling points greater than 175°C is fed to hydrocracking step b' (when present). Recycling a portion of the fraction containing compounds with boiling points greater than 175°C to at least one reaction step or upstream of the method according to the invention, particularly to hydrocracking step b'), advantageously allows for an increase in the yield of naphtha fractions with boiling points less than 175°C. Recycling also allows for the dilution of impurities and, moreover, allows for control of the temperature in one or more highly exothermic reaction steps.

[0189] According to another preferred variation, at least a portion of the fraction obtained from fractionation step d) containing compounds with boiling points greater than 175°C is fed into a second hydrocracking step b″ (when present).

[0190] Discharges can be installed in the recycling of fractions containing compounds with boiling points greater than 175°C. Depending on the operating conditions of the method, the discharge can be 0-10% by weight, preferably 0.5%-5% by weight, of the fraction containing compounds with boiling points greater than 175°C relative to the incoming feedstock.

[0191] Recycling of hydrocarbon effluents obtained from step c) and / or naphtha fractions with a boiling point less than or equal to 175°C obtained from step d).

[0192] A portion of the hydrocarbon effluent obtained from separation step c) or a portion of the naphtha fraction with a boiling point less than or equal to 175°C obtained from optional fractionation step d) can be recycled to form a recycle stream, which can be fed upstream of at least one of the reaction steps according to the method of the invention or directly to at least one of the reaction steps according to the method of the invention, particularly to hydrotreating step a) and / or hydrotreating step b). Optionally, a portion of the recycle stream can be fed to optional pretreatment step a0).

[0193] Preferably, at least a portion of the hydrocarbon effluent obtained from separation step c) or at least a portion of the naphtha fraction with a boiling point less than or equal to 175°C obtained from optional fractionation step d) is fed into hydrotreating step b).

[0194] Advantageously, the amount of the recycled stream, i.e., the fraction of recycled product obtained, is adjusted such that the weight ratio of the recycled stream to the feedstock containing the plastic pyrolysis oil, i.e., the feedstock to be processed throughout the process, is less than or equal to 10, preferably less than or equal to 5, and preferably greater than or equal to 0.001, more preferably greater than or equal to 0.01, and more preferably greater than or equal to 0.1. Very preferably, the amount of the recycled stream is adjusted such that the weight ratio of the recycled stream to the feedstock containing the plastic pyrolysis oil is 0.2-5.

[0195] Advantageously, for the initial stage of this method, the hydrocarbon fraction outside the method can be used as a recycle stream. Those skilled in the art know how to select the hydrocarbon fraction.

[0196] Recycling a portion of the resulting product into at least one reaction step of the method according to the invention or upstream thereof is advantageously possible by first diluting impurities and secondly by controlling the temperature in one or more highly exothermic reaction steps.

[0197] The hydrocarbon effluent or one or more hydrocarbon streams obtained by processing plastic pyrolysis oil according to the method of the invention have a composition compatible with the specifications of the feedstock entering the steam cracking unit. In particular, the composition of the hydrocarbon effluent or one or more hydrocarbon streams is preferably such that:

[0198] - The total content of metallic elements is less than or equal to 5.0 ppm by weight, preferably less than or equal to 2.0 ppm by weight, more preferably less than or equal to 1.0 ppm by weight, and even more preferably less than or equal to 0.5 ppm by weight, wherein:

[0199] The silicon (Si) content is less than or equal to 1.0 ppm by weight, preferably less than or equal to 0.6 ppm by weight, and

[0200] The iron (Fe) content is less than or equal to 100 ppb by weight.

[0201] - Sulfur content less than or equal to 500 ppm by weight, preferably less than or equal to 200 ppm by weight.

[0202] - The nitrogen content is less than or equal to 100 ppm by weight, preferably less than or equal to 50 ppm by weight, and more preferably less than or equal to 5 ppm by weight.

[0203] - The asphaltene content is less than or equal to 5.0 ppm by weight.

[0204] The total content of chlorine is less than or equal to 10 ppm by weight, preferably less than 1.0 ppm by weight.

[0205] The content of olefin compounds (monoolefins and dienes) is less than or equal to 5.0% by weight, preferably less than or equal to 2.0% by weight, and preferably less than or equal to 0.1% by weight.

[0206] The content is given as a relative weight concentration, weight percentage (%), parts per million (ppm) or parts per billion (ppb) relative to the total weight of the stream under consideration.

[0207] Therefore, the method according to the invention can process plastic pyrolysis oil to obtain an effluent that can be injected wholly or partially into a steam cracking unit.

[0208] Steam cracking step e) (optional)

[0209] At least one of the hydrocarbon effluent obtained from separation step c) or from the two hydrocarbon liquid streams obtained from optional step d) may be sent, in whole or in part, to steam cracking step e).

[0210] Advantageously, one or more gas fractions containing ethane, propane, and butane obtained from separation step c) and / or fractionation step d) may also be sent, in whole or in part, to steam cracking step e).

[0211] The steam cracking step e) is advantageously carried out in at least one pyrolysis furnace at a temperature of 700-900°C, preferably 750-850°C, and a relative pressure of 0.05-0.3 MPa. The residence time of hydrocarbon compounds is typically less than or equal to 1.0 second (s), preferably 0.1-0.5 s. Advantageously, steam is introduced upstream of the optional steam cracking step e) and after separation (or fractionation). The amount of water introduced (advantageously in steam form) is advantageously 0.3-3.0 kg water / kg of hydrocarbon compounds entering step e). Optional step e) is preferably carried out in parallel in multiple pyrolysis furnaces to adapt the operating conditions to the various feed streams to step e), and especially to the stream obtained from step d), and also to manage the decoking time in the pipelines. The furnace comprises one or more parallel pipelines. The furnace can also refer to a group of furnaces operating in parallel. For example, a furnace can be dedicated to cracking naphtha fractions containing compounds with a boiling point less than or equal to 175°C.

[0212] The effluents from various steam cracking furnaces are typically recombined to form the effluents prior to separation. It should be understood that the steam cracking step e) includes the steam cracking furnace, but also includes sub-steps related to steam cracking known to those skilled in the art. These sub-steps may specifically include heat exchangers, columns, and catalytic reactors, as well as recirculation back into the furnace. Columns typically allow for fractionation of the effluent to recover at least one light fraction containing hydrogen and compounds containing 2-5 carbon atoms, a fraction containing pyrolysis gasoline, and optionally a fraction containing pyrolysis oil. Columns also allow for the separation and fractionation of various components of the light fraction to recover at least one ethylene-rich fraction (C2 fraction), a propylene-rich fraction (C3 fraction), and optionally a butene-rich fraction (C4 fraction). Catalytic reactors, in particular, allow for the hydrogenation of the C2, C3, or even C4 fractions and pyrolysis gasoline. It is advantageous to recirculate saturated compounds, especially those containing 2-4 carbon atoms, back into the steam cracking furnace to increase the overall yield of olefins.

[0213] The steam cracking step e) yields an effluent containing at least one olefin (i.e., C2, C3, and / or C4 olefin) with 2, 3, and / or 4 carbon atoms, in a satisfactory amount, particularly greater than or equal to 30% by weight, especially greater than or equal to 40% by weight, or even greater than or equal to 50% by weight, of total olefins containing 2, 3, and 4 carbon atoms relative to the weight of the steam cracking effluent under consideration. The C2, C3, and C4 olefins can then be advantageously used as polyolefin monomers.

[0214] According to a preferred embodiment of the present invention, a method for processing a raw material containing plastic pyrolysis oil comprises, preferably, a series of steps, and preferably performed in a given order:

[0215] - Hydrogenation step a), hydrogenation treatment step b), separation step c), or

[0216] - Hydrogenation step a), hydrotreatment step b), separation step c), and fractionation step d), or

[0217] - Hydrogenation step a), hydrogenation treatment step b), separation step c), fractionation step d), and recycling of the fraction containing compounds with a boiling point less than or equal to 175°C to steps a) and / or b).

[0218] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), or

[0219] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), and fractionation step d), or

[0220] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), fractionation step d), and recycling of the fraction containing compounds with boiling points greater than 175°C to hydrocracking step b'), or

[0221] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), fractionation step d), and recycling of the fraction containing compounds with a boiling point less than or equal to 175°C to step a) or step b), or

[0222] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), fractionation step d), recycling the fraction containing compounds with boiling points greater than 175°C to hydrocracking step b'), and recycling the fraction containing compounds with boiling points less than or equal to 175°C to step a) or step b), or

[0223] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), fractionation step d), and recycling of the fraction containing compounds with boiling points greater than 175°C to hydrocracking step b''), or

[0224] - Hydrogenation step a), hydrotreatment step b), hydrocracking step b'), separation step c), fractionation step d), recycling the fraction containing compounds with boiling points greater than 175°C to hydrocracking step b''), and recycling the fraction containing compounds with boiling points less than or equal to 175°C to step a) or step b), or

[0225] - Hydrogenation step a), hydrotreatment step b), separation step c), fractionation step d), and hydrocracking step b′), or

[0226] - Hydrogenation step a), hydrotreatment step b), separation step c), fractionation step d), and hydrocracking step b'), and recycling the effluent from step b') to step c), or

[0227] - Hydrogenation step a), hydrotreatment step b), separation step c), fractionation step d), and hydrocracking step b'), and recycling the effluent from step b') to step c), and recycling the fraction containing compounds with a boiling point less than or equal to 175°C to step a) or step b).

[0228] All implementation schemes may additionally include a pretreatment step (a0), preferably consisting of it.

[0229] All implementation schemes may additionally include a steam cracking step (g), preferably consisting of it.

[0230] Analysis methods used

[0231] Analytical methods and / or standards for determining the characteristics of various streams, particularly raw materials and effluents to be processed, are known to those skilled in the art. These are specifically listed below in an informative manner. Other well-known equivalent methods, particularly equivalent IP methods, EN methods, or ISO methods, may also be used.

[0232] Table 1

[0233]

[0234]

[0235] (1) MAV method described in the literature: C. López-García 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. Attached Figure Description

[0236] about Figures 1 to 2 The information mentioned herein enables a better understanding of the invention, but the invention is not limited to... Figures 1 to 2 The specific implementations described herein. The various implementations presented may be used alone or in combination with each other, without any limitation on the combinations.

[0237] Figure 1 A flowchart illustrating a specific embodiment of the method of the present invention includes:

[0238] - In the presence of hydrogen-rich gas 2 and optionally amine supplied by stream 3, a step a) is performed to hydrogenate hydrocarbon feedstock 1 obtained from the pyrolysis of plastic in at least one fixed-bed reactor containing at least one hydrogenation catalyst to obtain effluent 4.

[0239] - In the presence of hydrogen 5, in at least one fixed-bed reactor containing at least one hydrotreating catalyst, step b) is performed on the effluent 4 obtained from step a) to hydrotreat the effluent 6 obtained from step a).

[0240] - Optionally, in the presence of hydrogen 7, in at least one fixed-bed reactor containing at least one hydrocracking catalyst, the effluent 6 obtained from step b) is subjected to hydrocracking step b') to obtain hydrocracking effluent 8.

[0241] - Separation step c) of effluent 8 in the presence of aqueous washing solution 9, such that at least one fraction 10 containing hydrogen, an aqueous fraction 11 containing dissolved salts and a hydrocarbon liquid fraction 12 can be obtained.

[0242] - Optionally, the fractionation step d) of the hydrocarbon liquid fraction 12 can be performed to obtain at least one gas fraction 13, a fraction 14 (naphtha fraction) containing compounds with a boiling point less than or equal to 175°C, and a fraction 15 (diesel fraction) containing compounds with a boiling point greater than 175°C.

[0243] At the outlet of step d), a portion of fraction 14, containing compounds with a boiling point less than or equal to 175°C, is fed to a steam cracking process (not shown). Another portion of fraction 14 is fed to hydrotreating step a) (fraction 14a) and hydrotreating step b) (fraction 14b). A portion of fraction 15, containing compounds with a boiling point greater than 175°C obtained from step d), is fed to hydrocracking step b') (fraction 15a), and another portion 15b constitutes the emissions.

[0244] Figure 2 A flowchart illustrating another specific embodiment of the method of the present invention, which is based on Figure 1 The flowchart specifically includes a second hydrocracking step b″), in which fraction 15, containing compounds with boiling points greater than 175°C, obtained from step d), is fed into the second hydrocracking step b″ (fraction 15a), which is carried out in at least one fixed-bed reactor containing at least one hydrocracking catalyst and fed with hydrogen (16). The second hydrocracking effluent (17) is recycled to separation step c). Another portion of fraction 15 constitutes emission 15b.

[0245] Instead of injecting amine stream 3 into the inlet of hydrogenation step a), it can be injected into the inlet of hydrotreatment step b), the inlet of hydrocracking step b′), the inlet of separation step c), or not injected at all, depending on the characteristics of the feedstock.

[0246] Figure 1 and Figure 2 Only the main steps and main streams are shown to provide a better understanding of the invention. It will be clearly understood that all the necessary equipment (containers, pumps, exchangers, furnaces, towers, etc.) is present, even if not shown. It should also be understood that, as described above, the hydrogen-rich gas stream (supply or recirculation) can be injected into the inlet of each reactor or catalyst bed, or between two reactors or two catalyst beds. Methods known to those skilled in the art for purifying and recirculating hydrogen may also be used. Example

[0247] Example 1 (according to the present invention)

[0248] The raw material 1 processed in this method is a plastic pyrolysis oil having the characteristics shown in Table 2 (i.e., containing 100% by weight of the plastic pyrolysis oil).

[0249] Table 2: Raw Material Characteristics

[0250]

[0251]

[0252] (1) MAV method described in the literature: C. López-García 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.

[0253] Feed 1 undergoes hydrogenation step a) in a fixed-bed reactor in the presence of hydrogen 2 and a NiMo-type hydrogenation catalyst supported on alumina, under the conditions shown in Table 3.

[0254] Table 3: Conditions for hydrogenation step a)

[0255] Reactor inlet temperature ℃ 280 Reactor outlet temperature ℃ 310 Average Temperature (WABT) ℃ 295 hydrogen partial pressure MPa (absolute pressure) 6.4 <![CDATA[H2 / HC (Volume coverage rate of hydrogen relative to the volume of the raw material)]]> <![CDATA[Nm 3 / m 3 ]]> 300 HSV (feed volumetric flow rate / catalyst volume) <![CDATA[h -1 ]]> 1.0

[0256] The conditions shown in Table 3 correspond to the conditions at the start of the cycle, and the average temperature (WABT) is increased by 1°C per month to compensate for catalytic deactivation.

[0257] At the outlet of hydrogenation step a), the observed conversion (=(initial concentration - final concentration) / initial concentration) is listed in Table 4.

[0258] Table 4: Conversion rate of the entity during hydrogenation step a).

[0259] Diene conversion rate ％ ＞60 Olefin conversion ％ ＞60 Silicon retention rate ％ ＞75

[0260] The effluent 4 obtained from the hydrogenation step a) is fed directly into the hydrogenation treatment step b) without separation. This step is carried out in a fixed bed, in the presence of hydrogen 5 and a NiMo type hydrogenation treatment catalyst supported on alumina, under the conditions shown in Table 5.

[0261] Table 5: Conditions for hydrotreating step b)

[0262] Average temperature of hydrotreating (WABT) ℃ 355 hydrogen partial pressure MPa (absolute pressure) 6.2 <![CDATA[H2 / HC (Volume coverage rate of hydrogen relative to the volume of the raw material)]]> <![CDATA[Nm 3 / m 3 ]]> 300 HSV (feed volumetric flow rate / catalyst volume) <![CDATA[h -1 ]]> 0.5

[0263] The conditions shown in Table 5 correspond to the conditions at the start of the cycle, and the average temperature (WABT) is increased by 1°C per month to compensate for catalytic deactivation.

[0264] The effluent 6 obtained from hydrotreating step b) is subjected to separation step c): an aqueous stream is injected into the effluent obtained from hydrotreating step b); the mixture is then treated in an acid scrubbing tower and a separation vessel to obtain gaseous fractions and liquid effluents. The yields of the various fractions obtained after separation are listed in Table 6 (yields are expressed as percentages, denoted as %m / m), representing the ratio of the mass of the various products obtained to the mass of the upstream feedstock in step a).

[0265] Table 6: Yields of various products obtained after separation

[0266] <![CDATA[Gas fraction (NH3 + H2S + C1-C4)]]> %m / m 0.94 Liquid fraction %m / m 99.41

[0267] Then, all or part of the obtained liquid fraction can be modified in the steam cracking step to form olefins, which can be polymerized to form recycled plastics.

[0268] Compared to catalytic deactivation observed according to the prior art, the method according to the present invention reduces catalytic deactivation during hydrogenation step a) and hydrogenation treatment step b).

[0269] Example 2 (not based on the present invention)

[0270] In this embodiment, which is based on the prior art and not according to the invention, the raw materials to be processed are the same as those described in Example 1 (see Table 2).

[0271] The feedstock was selectively hydrogenated in a fixed-bed reactor in the presence of hydrogen and a NiMo-type selective hydrogenation catalyst supported on alumina, under the conditions listed in Table 7 (step a).

[0272] Table 7: Conditions for selective hydrogenation step a)

[0273] Reactor inlet temperature ℃ 130 Reactor outlet temperature ℃ 138 Average Temperature (WABT) ℃ 134 hydrogen partial pressure MPa (absolute pressure) 6.4 H2 / HC (volume coverage ratio of hydrogen relative to feedstock volume) <![CDATA[Nm 3 / m 3 ]]> 10 HSV (feed volumetric flow rate / catalyst volume) <![CDATA[h -1 ]]> 6

[0274] The conditions shown in Table 7 correspond to the conditions at the start of the cycle, and the average temperature (WABT) increases by 4°C per month to compensate for catalytic deactivation.

[0275] At the outlet of the selective hydrogenation step a), the observed conversion (=(initial concentration - final concentration) / initial concentration) is listed in Table 8.

[0276] Table 8: Conversion rate of the entity during selective hydrogenation step a)

[0277] Diene conversion rate ％ 35 Olefin conversion ％ 6 Silicon retention rate ％ ＜1

[0278] The effluent from the selective hydrogenation step a) is sent directly to the hydrotreatment step b) without separation. This step is carried out in a fixed bed, in the presence of hydrogen, hydrocarbon recycle streams and a NiMo-type hydrotreatment catalyst supported on alumina, under the conditions listed in Table 9.

[0279] Table 9: Conditions for hydrotreating step b)

[0280] Average temperature of hydrotreating (WABT) ℃ 355 hydrogen partial pressure MPa (absolute pressure) 6.2 <![CDATA[H2 / HC (Volume coverage rate of hydrogen relative to the volume of the raw material)]]> <![CDATA[Nm 3 / m 3 ]]> 300 HSV (feed volumetric flow rate / catalyst volume) <![CDATA[h -1 ]]> 0.5

[0281] The conditions shown in Table 9 correspond to the conditions at the start of the cycle, and the average temperature (WABT) increases by 2°C per month to compensate for catalytic deactivation.

[0282] Separation step c) involves injecting an aqueous stream into the effluent from hydrotreating step b); then treating the mixture in an acid scrubbing tower and a separation vessel to obtain gaseous fractions and liquid effluents. The yields of the various fractions obtained after separation are listed in Table 10 (yields are expressed as percentages, denoted as %m / m), representing the ratio of the mass of the various products obtained to the mass of the upstream feedstock from step a).

[0283] Table 10: Yields of various products obtained after separation

[0284] <![CDATA[Gas fraction (NH3 + H2S + C1 - C4)]]> %m / m 0.85 Liquid distillate %m / m 99.50

[0285] The method performed according to the prior art and not according to the invention produces catalytic deactivation during the selective hydrogenation step a) and the hydrogenation treatment step b), said catalytic deactivation being greater than the catalytic deactivation observed during the hydrogenation step a) and the hydrogenation treatment step b) in the method performed according to the invention.

Claims

1. Process for treating a feedstock comprising plastic pyrolysis oil, said plastic pyrolysis oil comprising chlorinated compounds, comprising: a) a hydrogenation step a) fed with the feedstock comprising plastic pyrolysis oil, said step a) being carried out at a temperature of 50-370°C to obtain a hydrogenated effluent, b) a separation step b) fed with the hydrogenated effluent obtained from step a) and an aqueous solution, said step b) being carried out at a temperature of 50-370°C to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent, the separation step b) comprising injection of the aqueous solution into the hydrogenated effluent obtained from step a) upstream of a washing / separation section, c) a separation step c) fed with the hydrogenated effluent obtained from step b) and an aqueous solution, said step c) being carried out at a temperature of 50-370°C to obtain at least one gaseous effluent, an aqueous effluent and a hydrocarbon effluent, the separation step c) comprising injection of the aqueous solution into the hydrogenated effluent obtained from step b) upstream of a washing / separation section, the space time velocity being defined as the ratio between the hourly flow rate by volume of the feedstock comprising plastic pyrolysis oil and the volume of the catalyst(s). a) a hydrogenation step carried out in a hydrogenation reaction section using at least one fixed bed reactor comprising n catalytic beds, n being an integer greater than or equal to 1, each catalytic bed comprising at least one hydrogenation catalyst, said hydrogenation reaction section being fed at least with said feedstock and a gaseous 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 abs and a space time velocity of 0.1-10.0 h"1, the outlet temperature of the reaction section of step a) being at least 15°C higher than the inlet temperature of the reaction section of step a) to obtain a hydrogenated effluent; -1 b) a hydrocracking step carried out in a hydrocracking reaction section using at least one fixed bed reactor comprising n catalytic beds, n being an integer greater than or equal to 1, each catalytic bed comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed at least with said hydrogenated effluent and a gaseous stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature of 140-400°C, a hydrogen partial pressure of 1.0-10.0 MPa abs and a space time velocity of 0.1-10.0 h"1, the outlet temperature of the reaction section of step b) being at least 15°C higher than the inlet temperature of the reaction section of step b) to obtain a hydrocracked effluent; b) a hydrotreating step carried out in a hydrotreating reaction section using at least one fixed bed reactor comprising n catalytic beds, n being an integer greater than or equal to 1, each catalytic bed comprising at least one hydrotreating catalyst, said hydrotreating reaction section being at least fed with said hydrogenated effluent obtained from step a) and a gaseous stream comprising 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 abs and a space velocity of 0.1 -10.0 h -1 The average temperature of the reaction section of step b) is higher than the average temperature of the hydrogenation reaction section of step a) to obtain a hydrotreated effluent.

2. Process according to claim 1, comprising a step d) of fractionation of all or part of the hydrocarbon effluent obtained from step c) to obtain at least one gaseous effluent and at least one fraction comprising compounds having a boiling point lower than or equal to 175°C and at least one hydrocarbon fraction comprising compounds having a boiling point greater than 175°C.

4. Process according to claim 3, wherein step c) is fed with the hydrocracking effluent obtained from step b') and an aqueous solution, the separation step c) comprising injection of the aqueous solution into the hydrocracking effluent obtained from step b') upstream of a washing / separation section.

7. Process according to claim 1 or 2, wherein the outlet temperature of step a) is at least 30°C higher than the inlet temperature of step a).

3. The method according to claim 1 or 2, comprising a hydrocracking step b') in a hydrocracking reaction section using at least one fixed bed comprising n catalyst beds, where n is an integer greater than or equal to 1, each catalyst bed containing at least one hydrocracking catalyst, the hydrocracking reaction section being fed at least the hydrotreated effluent obtained from step b') and / or a fraction containing compounds with a boiling point greater than 175°C and a gaseous stream containing hydrogen obtained from step d'), the hydrocracking reaction section being maintained at an average temperature of 250-450°C, a hydrogen partial pressure of 1.5-20.0 MPa absolute, and a h⁻¹ of 0.1-10.0 h⁻¹. -1 The process is carried out at a space-time velocity to obtain hydrocracking effluent, which is then sent to separation step c).

8. Process according to claim 2, wherein at least part of the hydrocarbon effluent obtained from separation step c) or at least part of the naphtha fraction comprising compounds having a boiling point lower than or equal to 175°C obtained from fractionation step d) is sent to hydrogenation step a) and / or to hydroprocessing step b).

5. The process according to claim 1 or 2, wherein the amount of the gas stream comprising hydrogen fed to the reaction section of step a) is such that the hydrogen coverage is from 50 to 1000 Nm 3 of hydrogen per m 3 of feedstock.

6. The process according to claim 5, wherein the amount of the gas stream comprising hydrogen fed to the reaction section of step a) is such that the hydrogen coverage is from 200 to 300 Nm 3 of hydrogen per m 3 of feedstock.

9. Process according to claim 3, wherein at least part of the fraction comprising compounds having a boiling point greater than 175°C obtained from fractionation step d) is sent to hydrogenation step a) and / or to hydroprocessing step b) and / or to hydrocracking step b').

10. Process according to claim 1 or 2, comprising a pre-treatment step a0) of the feedstock comprising plastic pyrolysis oil, said pre-treatment step being carried out upstream of hydrogenation step a) and comprising a filtration step and / or an electrostatic separation step and / or a washing step with an aqueous solution and / or an adsorption step.

11. Process according to claim 2, wherein at least one of the two hydrocarbon liquid streams obtained from separation step c) or from step d) is sent in whole or in part to a steam cracking step e) carried out in at least one pyrolysis furnace at a temperature of 700-900°C and at a relative pressure of 0.05-0.3 MPa.

12. Process according to claim 1 or 2, wherein the reaction section of step a) uses at least two reactors operating in a replaceable mode.

13. Process according to claim 1 or 2, wherein an amine-containing stream is injected upstream of step a). ​ ​ 14. The process according to claim 1 or 2, wherein the hydrogenation catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clays and mixtures thereof and a hydrogen-dehydrogenation function comprising at least one Group VIII element and at least one Group VIB element, or at least one Group VIII element.

15. The process according to claim 1 or 2, wherein the hydroprocessing catalyst comprises a support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clays and mixtures thereof and a hydrogen-dehydrogenation function comprising at least one Group VIII element and / or at least one Group VIB element.

16. The process according to claim 3, said process further comprising a second hydrocracking step b'') carried out in a hydrocracking reaction section using at least one fixed bed comprising n catalytic beds, n being an integer greater than or equal to 1, each catalytic bed comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with the fraction comprising compounds having a boiling point greater than 175°C obtained from step d) and a gaseous stream comprising hydrogen, said hydrocracking reaction section being used at a temperature comprised between 250 and 450°C, a hydrogen partial pressure comprised between 1.5 and 20.0 MPa abs and a space time velocity comprised between 0.1 and 10.0 h"1 to obtain a hydrocracking effluent which is sent to the separation step c). -1 8 17. The process according to claim 3, wherein the hydrocracking catalyst comprises a support selected from the group consisting of halogenated alumina, combinations of boron and aluminum oxides, amorphous silica-alumina and zeolites and a hydrogen-dehydrogenation function comprising at least one Group VIB metal selected from the group consisting of chromium, molybdenum and tungsten and / or at least one Group VIII metal selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, alone or as a mixture.

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