Method for treating pyrolysis oils for recycling in a catalytic cracking unit of hydrorefining units

Abstract

Process for treating a feedstock comprising a plastic and / or tyre and / or solid recovered fuel pyrolysis oil comprising halogenated compounds, comprising:a) a hydrotreating step in order to obtain a partially hydrotreated effluent having a reduced content of halogenated compounds,b) a separation step, fed with the partially hydrotreated effluent from step a) and an aqueous solution in order to obtain a gaseous effluent, an aqueous effluent and a partially hydrotreated hydrocarbon effluent,c) a step of fluid catalytic cracking or hydrorefining of a petroleum feedstock and / or a feedstock resulting from biomass conversion in which the partially hydrotreated hydrocarbon effluent is introduced as co-feedstock without undergoing another hydrotreating step carried out at higher temperature and / or pressure beforehand, the mixture of petroleum feedstock and / or biomass feedstock and the partially hydrotreated hydrocarbon effluent having a content of halogen compounds of less than or equal to 10 ppm by weight.

Description

TECHNICAL FIELDThe present invention relates to a process for treating a plastic and / or tyre and / or solid recovered fuel (SRF) pyrolysis oil in order to obtain a partially hydrotreated pyrolysis oil which can be upgraded as co-feedstock with petroleum feedstocks and / or feedstocks resulting from biomass conversion in a unit of a refinery such as a fluid catalytic cracking unit or hydrorefining units using hydrogen, such as a hydrotreating, hydrocracking or hydroconversion unit. More particularly, the present invention relates to a process for treating a pyrolysis oil with a view to eliminating the halogenated compounds thereof in order to be able to easily upgrade this oil in the existing units of a refinery.PRIOR ARTPlastic waste is generally a mixture of several polymers, for example mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride or polystyrene. Furthermore, depending on the uses, the plastics may contain, in addition to the polymers, other compounds, such as plasticizers, pigments, dyes or else polymerization catalyst residues. Plastic waste may additionally contain, in a minor amount, biomass originating, for example, from household waste. The treatment of the waste, on the one hand, in particular the storage, the mechanical treatments, the sorting, the pyrolysis, and also the storage and the transportation of pyrolysis oil, on the other hand, can also cause corrosion.With regard to tyres, they are mainly constituted of rubbers, for their elastic property (mixture of elastomers of the type of crosslinked synthetic and natural rubbers, with the addition of adjuvants of the type of silica, resin, sulfur, zinc oxide, carbon black, and the like), and of textile and metal fibres, for their reinforcing property.

[0004] Solid recovered fuels (SRFs), also called refuse derived fuel (RDF), are solid non-hazardous wastes prepared with a view to energy upgrading, whether they originate from household and similar waste, from waste from economic activities or from waste from construction and demolition. SRFs are generally a mixture of any combustible waste, such as used tyres, food by-products (fats, animal meal, and the like), viscose and wood waste, light fractions resulting from shredders (for example from used vehicles, electrical and electronic equipment (WEEE)), household and commercial waste, residues from the recycling of various types of waste, including certain municipal wastes, plastic waste, textiles or wood, inter alia. SRFs generally contain plastic waste.

[0005] Plastics resulting from collection and sorting channels or recycled tyres or else SRFs can undergo a step of pyrolysis in order to obtain, inter alia, pyrolysis oils. These oils generally comprise a lot of impurities, in particular halogenated compounds, notably chlorine-based compounds, but also diolefins, olefins, metals, in particular iron, silicon, or else heteroelements such as sulfur, oxygen and nitrogen, and insoluble materials.

[0006] These plastic and / or tyre and / or SRF pyrolysis oils are generally incinerated in order to generate electricity and / or used as fuel in industrial or district heating boilers.

[0007] Another route for upgrading pyrolysis oils is the use of these pyrolysis oils as feedstock of a steam cracking unit in order to (re) create olefins, the latter being constituent monomers of certain polymers. However, plastic and / or tyre pyrolysis oils have impurities at often high contents that are incompatible with steam cracking units or units located downstream of steam cracking units, in particular polymerization processes and selective hydrogenation processes.

[0008] One way of removing these impurities contained in the pyrolysis oils is to carry out a hydrotreating in the presence of catalysts. Steam cracking units require very high feedstock purities, notably low contents of chlorine, diolefins, olefins, metals and sulfur. Hydrotreatment upstream of steam cracking is then often carried out in several steps and under quite stringent conditions, in particular in terms of temperature and pressure, in order to achieve the required specifications. Such methods are for example described in WO2016 / 142808, WO2016 / 142809, WO2018 / 055555, WO2021 / 110395 or WO2021 / 165178.

[0009] Another way of upgrading plastic and / or tyre pyrolysis oils is the use of these pyrolysis oils as a feedstock in fluid catalytic cracking (FCC) units in order to produce mainly gasoline. Such processes are for example described in U.S. Pat. No. 10,442,997, WO2021 / 133893, WO2021 / 133889, WO2021 / 133895 and WO2021 / 201932.

[0010] Although the requirements in terms of specifications are different and often lower in terms of purity for an FCC feedstock, the hydrotreatments carried out upstream to remove the impurities described in the prior art are generally also carried out under quite stringent conditions. Document WO2021 / 201932 describes for example an FCC pretreatment by hydrotreating at a temperature of between 349-415° C. (660-780° F.) and a pressure of between 6.8 and 13.8 MPa (68-138 bar, 1000-2000 psi).

[0011] The present invention proposes a process for mild hydrotreatment of a plastic and / or tyre and / or SRF pyrolysis oil making it possible in particular to reduce its content of halogenated compounds, and in particular of chlorine, in order to obtain a pyrolysis oil stripped of most of the halogenated compounds and which can then be sent as co-feedstock with petroleum feedstocks and / or feedstocks resulting from biomass conversion to a refinery unit such as an FCC unit or a hydrorefining unit using hydrogen such as a hydrocracking, hydrotreating or hydroconversion unit.

[0012] Chlorine is generally the limiting contaminant for treating pyrolysis oils in the existing units of a refinery. Indeed, chlorine, even at a low content (<10 ppm by weight, or even <5 ppm by weight), is responsible for corrosion (in the form of HCl) which can occur in existing units, the metallurgy of which is generally not designed to withstand chlorine levels of greater than 10 ppm by weight, or even 5 ppm by weight in the feedstock.

[0013] Unlike the hydrotreating processes described in the prior art, the process according to the invention is directed toward a mild hydrotreatment, in particular at low pressure and moderate temperatures. The mild operating conditions in the hydrotreatment, combined with a separation step with washing make it possible to largely remove the halogenated compounds while retaining as much as possible the diolefins and olefins which can for example be upgraded in the FCC (for the production of propylene).

[0014] The process according to the invention is mainly focused on the removal of halogenated compounds in order to make the pyrolysis oil compatible as a feedstock in the downstream units. The process according to the invention is not necessarily directed toward complete hydrotreatment of the oil. The other impurities contained in the pyrolysis oils (metals, silicon, nitrogen, etc.) are not necessarily completely removed during the process according to the invention, although the operating conditions make it possible to remove at least a portion thereof. These impurities will possibly be converted or removed in downstream units, the residual contents of impurities being compatible with these units.

[0015] The “mild” hydrotreatment of the present invention is a hydrotreatment carried out under carefully chosen pressure, temperature and hourly space velocity conditions that are generally more moderate compared to conventional hydrotreatments known from the prior art aimed at removing all the impurities. The hydrotreatment of the present invention makes it possible in particular to largely remove the halogenated compounds while retaining as much as possible the diolefins and olefins.

[0016] The objective of the present invention is then to propose a process for treating plastic and / or tyre pyrolysis oils that is inexpensive, easy to carry out and can easily be integrated into existing refinery units. The fact of using mild operating conditions makes it possible to minimize the hydrogen consumption, thus minimizing the cost of this purification and also the operating and investment costs while removing the chlorine content as much as possible.

[0017] In addition, the process according to the invention can be carried out in a unit dedicated to pyrolysis oils, and therefore in a low-capacity unit making it possible to obtain a partially hydrotreated pyrolysis oil with a low enough content of halogenated compounds to be sent directly to co-processing in an existing refinery unit. Existing units do not need to be modified.

[0018] The unit of the process according to the invention can be easily integrated into refining units and can also use, owing to the low pressure required, hydrogen supply units that are already present in the refinery.SUMMARY OF THE INVENTION

[0019] More specifically, the invention relates to a process for treating a pyrolysis feedstock, comprising a plastic and / or tyre and / or solid recovered fuel pyrolysis oil comprising halogenated compounds, said process comprising:

[0020] a) a hydrotreating step carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the pyrolysis feedstock and a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 100° C. and 220° C., a partial pressure of hydrogen of between 1.0 and 3.0 MPa abs, and an hourly space velocity of between 0.05 and 5 h−1, the hydrogen coverage being between 5 and 50 Nm3 of hydrogen per m3 of pyrolysis feedstock, in order to obtain a partially hydrotreated effluent having hydrocarbon compounds with a reduced halogen content,

[0021] b) a separation step, fed with the partially hydrotreated effluent from step a) and an aqueous solution in order to obtain at least a gaseous effluent, an aqueous effluent and a partially hydrotreated hydrocarbon effluent,

[0022] c) a step of fluid catalytic cracking or hydrorefining of a petroleum feedstock and / or a feedstock resulting from biomass conversion in which at least one portion of the partially hydrotreated hydrocarbon effluent from step b) is introduced as a co-feedstock, said partially hydrotreated hydrocarbon effluent from step b) being introduced without first undergoing another hydrotreating step carried out at higher temperature and / or pressure than the temperature and / or pressure of step a), said mixture of said petroleum feedstock and / or said feedstock resulting from biomass conversion and the partially hydrotreated hydrocarbon effluent from step b) having a halogen content of less than or equal to 10 ppm by weight.

[0023] According to a variant, the weight ratio of the flow of the partially hydrotreated hydrocarbon effluent from step b) to the flow of petroleum feedstock and / or feedstock resulting from biomass conversion introduced in step c) is less than 1.

[0024] According to a variant, the pyrolysis feedstock consists of a plastic and / or tyre and / or solid recovered fuel pyrolysis oil.

[0025] According to a variant, the content of halogenated compounds in said pyrolysis feedstock is between 1 and 5000 ppm by weight.

[0026] According to one variant, said hydrotreating catalyst of step a) comprises a support chosen from alumina, silica, silica-aluminas, magnesia, clays and mixtures thereof and a hydrogenating-dehydrogenating function comprising either at least one group VIII element and at least one group VIB element, or at least one group VIII element.

[0027] According to a variant, said process comprises at least one step a0) of pretreating the pyrolysis feedstock comprising a plastic and / or tyre and / or SRF pyrolysis oil, said pretreatment step being carried out upstream of step a), and comprises an adsorption step and / or a filtration step and / or a centrifugation step and / or a settling step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or a gas stripping step.

[0028] According to a variant, the petroleum feedstock is chosen from gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, waste oils, deasphalted residues or crudes, petroleum feedstocks originating from thermal or catalytic conversion processes, or mixtures of such feedstocks.

[0029] According to a variant, the feedstock derived from biomass is chosen from vegetable oils, oils from algae or algal oils, fish oils, waste edible oils, and fats of vegetable or animal origin; fatty acid methyl esters of plant and / or animal origin, fatty acid methyl esters from waste edible vegetable oils, feedstocks originating from thermal or catalytic biomass conversion processes, or mixtures of such feedstocks.

[0030] According to an alternative form, the reaction section of step a) employs at least two reactors operating in permutable mode.

[0031] According to a variant, the fluid catalytic cracking step c) is carried out in a fluid catalytic cracking reaction section in a substantially vertical reactor either in upflow mode or in downflow mode in the presence of a zeolite catalyst at a reactor temperature of between 450° C. and 600° C. with a contact time in the reactor of less than 1 minute.

[0032] According to a variant, the hydrorefining step c) is a hydrotreating step carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 180° C. and 480° C., a partial pressure of hydrogen of between 0.5 and 25 MPa abs., an hourly space velocity of between 0.1 and 20 h−1 and a hydrogen coverage of between 50 and 5000 Nm3 of hydrogen per m3 of feedstock.

[0033] According to a variant, the hydrorefining step c) is a hydrocracking step carried out in a hydrocracking reaction section comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature of between 250° C. and 480° C., a partial pressure of hydrogen of between 2 and 25 MPa abs., an hourly space velocity of between 0.5 and 40 h−1, and a hydrogen coverage of between 80 and 5000 Nm3 of hydrogen per m3 of feedstock.

[0034] According to a variant, the hydrorefining step c) is a hydroconversion step carried out in a hydroconversion reaction section comprising at least one hydroconversion catalyst, said hydroconversion reaction section being fed with a gas stream comprising hydrogen, said hydroconversion reaction section being used at an average temperature of between 340° C. and 550° C., a partial pressure of hydrogen of between 2 and 38 MPa abs., an hourly space velocity of between 0.05 and 10 h−1, and a hydrogen coverage of between 50 and 5000 Nm3 of hydrogen per m3 of feedstock.

[0035] In the continuation of the text, the term “pyrolysis oil” is understood to mean an oil resulting from the pyrolysis of plastics and / or of tyres and / or of SRFs, unless otherwise indicated.

[0036] According to the present invention, the pressures are absolute pressures, also denoted abs., and are given in MPa absolute (or MPa abs.), unless otherwise indicated.

[0037] According to the present invention, the expressions “of between . . . and . . . ” and “between . . . and . . . ” are equivalent and mean that the limit values of the interval are included in the described range of values. If such were not the case and if the limiting values were not included in the range described, such a clarification will be introduced by the present invention.

[0038] Within the meaning of the present invention, the various parameter ranges for a given step, such as the pressure ranges and the temperature ranges, can be used alone or in combination. For example, for the purposes of the present invention, a range of preferred pressure values can be combined with a range of more preferred temperature values.

[0039] In the text hereinbelow, specific and / or preferred embodiments of the invention may be described. They can be implemented separately or combined together, without limitation of combination when this is technically feasible.

[0040] Subsequently, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor-in-chief D. R. Lide, 81st edition, 2000-2001). For example, group VIII (or VIIIB) according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification.

[0041] The content of metals is measured by X-ray fluorescence.DETAILED DESCRIPTIONThe Pyrolysis Feedstock

[0042] According to the invention, a “plastic pyrolysis oil or tyre pyrolysis oil or SRF pyrolysis oil” is an oil, advantageously in liquid form at ambient temperature, resulting from the pyrolysis of plastics, preferably of plastic waste originating in particular from collection and sorting channels, or resulting from the pyrolysis of used tyres or else from the pyrolysis of SRFs. It comprises in particular a mixture of hydrocarbon compounds, especially paraffins, olefins (mono- and / or diolefins), naphthenes and aromatics. At least 80% by weight of these hydrocarbon compounds preferably have a boiling point of less than 700° C. and preferably of less than 550° C. In particular, depending on the origin of the pyrolysis oil, the latter can comprise up to 70% by weight of paraffins, up to 90% by weight of naphthenes, up to 90% by weight of olefins and up to 90% by weight of aromatics, it being understood that the sum of the paraffins, of the naphthenes, of the olefins and of the aromatics is equal to 100% by weight of the hydrocarbon compounds.

[0043] The pyrolysis oil can comprise diolefins. The content of diolefins is commonly determined indirectly as the maleic anhydride value (MAV). The method is based on the Diels-Alder addition reaction between the conjugated diolefins and the maleic anhydride. The method for the determination of the MAV is described in 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. The MAV is expressed in mg of maleic anhydride having reacted with 1 g of sample (mg / g). The MAV varies between 5 and 100 mg / g in the pyrolysis oils.

[0044] The density of the pyrolysis oil, measured at 15° C. according to the ASTM D4052 method, is generally of between 0.75 g / cm3 and 0.99 g / cm3, preferably of between 0.75 g / cm3 and 0.95 g / cm3.

[0045] The pyrolysis oil may also comprise, and usually does comprise, impurities, such as metals, notably iron, silicon or halogenated compounds, notably chlorinated compounds. These impurities can be present in the pyrolysis oil at high contents, for example up to 500 ppm by weight or else 700 ppm by weight, or 1000 ppm by weight, and even 5000 ppm by weight, of halogen elements (in particular chlorine but also bromine, fluorine, iodine or astatine) contributed by halogenated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or else between 1 and 500 ppm by weight of halogen elements. The pyrolysis oil can contain up to 500 ppm by weight or else 700 ppm by weight, or 1000 ppm by weight and even 5000 ppm by weight of chlorine element contributed by chlorinated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or else between 1 and 500 ppm by weight of chlorine element.

[0046] The oil can comprise up to 200 ppm by weight, or 1500 ppm by weight, of metal or semi-metal elements, and generally between 1 and 200 ppm by weight or between 1 and 1500 ppm by weight of metal or semi-metal elements. Alkali metals, alkaline-earth metals, transition metals, post-transition metals and metalloids can be put into the same category as contaminants of metal nature, referred to as metals or metal or semi-metal elements. In particular, the metals or metal or semi-metal elements comprise silicon, iron or both of these elements. The pyrolysis oil can in particular comprise up to 200 ppm by weight or else 1000 ppm by weight of silicon, and generally between 1 and 200 ppm by weight or between 1 and 1000 ppm by weight or else between 1 and 500 ppm by weight of silicon. The pyrolysis oil can in particular comprise up to 50 ppm by weight or else 100 ppm by weight of iron, and generally between 1 and 50 ppm by weight or between 1 and 100 ppm by weight of iron. The pyrolysis oil can also comprise phosphorus, sodium, calcium, potassium and magnesium.

[0047] The pyrolysis oil can also comprise other impurities, such as heteroelements contributed in particular by sulfur compounds, oxygen compounds and / or nitrogen compounds, at contents generally of less than 40 000 ppm by weight of heteroelements and preferably of less than 15 500 ppm by weight of heteroelements, and generally between 1 and 40 000 ppm by weight or between 1 and 15 500 ppm by weight of heteroelements.

[0048] The sulfur compounds are generally present in a content of less than 15 000 ppm by weight and preferably of less than 10 000 ppm by weight, and generally between 1 and 15 000 ppm by weight or between 1 and 10 000 ppm by weight of sulfur compounds.

[0049] The oxygen compounds are generally present in a content of less than 15 000 ppm by weight and preferably of less than 10 000 ppm by weight, and generally between 1 and 15 000 ppm by weight or between 1 and 10 000 ppm by weight of oxygen compounds.

[0050] The nitrogen compounds are generally present in a content of less than 10 000 ppm by weight and preferably of less than 5000 ppm by weight, and generally between 1 and 10 000 ppm by weight or between 1 and 5000 ppm by weight of nitrogen compounds.

[0051] The contents of sulfur, oxygen and / or nitrogen compounds often depend on the origin of the oil. Thus, tyre pyrolysis oils generally contain more heteroelements than plastic pyrolysis oils, in particular sulfur compounds.

[0052] The pyrolysis oil can also comprise other impurities, such as heavy metals, for example mercury, arsenic, zinc and lead, for example up to 100 ppb by weight or else 200 ppb by weight of mercury or of arsenic, and generally between 1 and 200 ppb by weight or between 1 and 100 ppb by weight of heavy metals.

[0053] The pyrolysis feedstock of the process according to the invention comprises at least one plastic and / or tyre and / or SRF pyrolysis oil. Said feedstock can consist solely of pyrolysis oil(s). Preferably, said feedstock comprises at least 50% by weight, in a preferred way between 70% and 100% by weight, of pyrolysis oil, relative to the total weight of the feedstock, that is to say preferably between 50% and 100% by weight and in a preferred way between 70% and 100% by weight of plastic pyrolysis oil.

[0054] Particularly preferably, the pyrolysis feedstock of the process according to the invention consists solely of plastic and / or tyre and / or SRF pyrolysis oil(s).

[0055] In the case of a mixture of a plastic pyrolysis oil, a tyre pyrolysis oil and / or an SRF pyrolysis oil, this mixture can be produced in any proportion.

[0056] According to another variant, the pyrolysis feedstock of the process according to the invention introduced in step a) can comprise, in addition to the pyrolysis oil(s), a conventional petroleum feedstock or a feedstock resulting from biomass conversion which is then co-treated with the pyrolysis oil of the feedstock.

[0057] The conventional petroleum feedstock introduced in step a) can advantageously be a cut or a mixture of cuts of naphtha or gas oil type.

[0058] The feedstock resulting from biomass conversion introduced in step a) can advantageously be chosen from vegetable oils, oils from algae or algal oils, fish oils, waste edible oils, and fats of vegetable or animal origin, or mixtures of such feedstocks. Said vegetable oils can advantageously be crude or refined, completely or partly, and result from plants chosen from rape, sunflower, soybean, palm, olive, coconut, copra, castor oil plant, cotton plant, peanut oil, linseed oil and sea kale oil, and all the oils resulting, for example, from sunflower or rape by genetic modification or hybridization, this list not being limiting. Said animal fats are advantageously chosen from blubber and fats composed of residues from the food industry or resulting from the catering industries. Frying oils, various animal oils, such as fish oils, tallow or lard, can also be used. The feedstock resulting from biomass conversion can also advantageously be chosen from fatty acid methyl esters of vegetable and / or animal origin or else fatty acid methyl esters from waste edible vegetable oils.

[0059] The feedstock resulting from biomass conversion can also be chosen from feedstocks originating from thermal or catalytic biomass conversion processes, such as oils which are produced from biomass, in particular from lignocellulosic biomass, with various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term “biomass” refers to a material derived from recently living organisms, which includes plants, animals and by-products thereof. The term “lignocellulosic biomass” denotes biomass derived from plants or from by-products thereof. The lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and of an aromatic polymer (lignin).

[0060] The feedstock resulting from biomass conversion can also advantageously be chosen from feedstocks resulting from the papermaking industry.

[0061] The plastic and / or tyre and / or SRF pyrolysis oil can result from a thermal or catalytic pyrolysis treatment or else be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and of hydrogen).Pretreatment (Optional)

[0062] Said feedstock comprising a plastic and / or tyre and / or SRF pyrolysis oil can advantageously be pretreated in at least one optional pretreatment step a0), prior to the hydrotreating step a), in order to obtain a pretreated feedstock which feeds step a).

[0063] According to a variant, this optional pretreatment step a0) makes it possible to reduce the amount of contaminants and of solid particles, in particular the amount of iron and / or of silicon and / or of chlorine, possibly present in the feedstock comprising a pyrolysis oil. This optional step a0) makes possible in particular the removal of sediments which can be formed as a result of the unstable nature of the pyrolysis oils and / or of a problem of compatibility between two different feedstocks. Thus, an optional step a0) of pretreatment of the feedstock comprising a pyrolysis oil is advantageously carried out, in particular when said feedstock comprises more than 10 ppm by weight, notably more than 20 ppm by weight, more particularly more than 50 ppm by weight, of metal elements and / or of solid particles, and in particular when said feedstock comprises more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, indeed even more than 20 ppm by weight, of silicon. Likewise, an optional step a0) of pretreatment of the feedstock comprising a pyrolysis oil is advantageously carried out in particular when said feedstock comprises more than 10 ppm by weight, notably more than 20 ppm by weight, more particularly more than 50 ppm by weight, of chlorine.

[0064] Said optional pretreatment step a0) can be carried out by any method known to those skilled in the art which makes it possible to reduce the amount of contaminants. It can in particular comprise an adsorption step and / or a filtration step and / or a centrifugation step and / or a settling step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or a gas stripping step.

[0065] The optional pretreatment step a0) is advantageously carried out at a temperature of between 20° C. and 400° C., preferably between 40° C. and 350° C., and at a pressure between 0.15 and 10.0 MPa abs., preferably between 0.2 and 7.0 MPa abs.

[0066] According to a variant, said optional pretreatment step a0) is carried out in an adsorption section operated in the presence of at least one adsorbent. The adsorbent can be chosen from a zeolite, activated carbon, a clay, a silica or an alumina. Preferably, the adsorbent is an alumina, having a specific surface area greater than or equal to 100 m2 / g, preferably greater than or equal to 200 m2 / g. The specific surface area of said at least one adsorbent is advantageously less than or equal to 600 m2 / g, in particular less than or equal to 400 m2 / g. The specific surface area of the adsorbent is a surface area measured by the BET method, that is to say the specific surface area determined by nitrogen adsorption in accordance with standard ASTM D 3663-78 drawn up from the Brunauer-Emmett-Teller method described in the periodical The Journal of the American Chemical Society, 6Q, 309 (1938).

[0067] Advantageously, said adsorbent comprises less than 1% by weight of metal elements and preferably is devoid of metal elements. Metal elements of the adsorbent should be understood as meaning the elements from groups 6 to 10 of the Periodic Table of the Elements (new IUPAC classification). The residence time of the feedstock in the adsorption section is generally of between 1 and 180 minutes.

[0068] Said adsorption section of the optional step a0) comprises at least one adsorption column, preferably comprises at least two adsorption columns, preferentially between two and four adsorption columns, containing said adsorbent. When the adsorption section comprises two adsorption columns, one operating mode can be a “swing” operation, wherein one of the columns is on-line, that is to say in operation, while the other column is in reserve. When the adsorbent of the on-line column is spent, this column is isolated, while the column in reserve is placed on-line, that is to say in operation. The spent adsorbent can subsequently be regenerated in situ and / or replaced with fresh adsorbent in order for the column containing it to be again able to be placed back on-line once the other column has been isolated.

[0069] Another operating mode is to have at least two columns operating in series. When the adsorbent of the column placed at the head is spent, this first column is isolated and the spent adsorbent is either regenerated in situ or replaced with fresh adsorbent. The column is subsequently brought back on-line in the last position, and so on. This operation is referred to as permutable mode, or as PRS for permutable reactor system or else as “lead and lag”.

[0070] The combination of at least two adsorption columns makes it possible to overcome the possible and potentially rapid poisoning and / or clogging of the adsorbent due to the combined action of the metallic contaminants, of the diolefins, of the gums obtained from the diolefins and of the insoluble matter that may be present in the pyrolysis oil to be treated. This is because the presence of at least two adsorption columns facilitates the replacement and / or the regeneration of the adsorbent, advantageously without shutdown of the pretreatment unit, indeed even of the process, thus making it possible to reduce the risks of clogging and thus to avoid shutdown of the unit due to clogging, to control the costs and to limit the consumption of adsorbent.

[0071] According to another variant, said optional pretreatment step a0) is carried out in a section for washing with an aqueous solution, for example water, or an acidic or basic solution. This washing section can comprise items of equipment which make it possible to bring the feedstock into contact with the aqueous solution and to separate the phases so as to obtain, on the one hand, the pretreated feedstock and, on the other hand, the aqueous solution comprising impurities. These items of equipment can include, for example, a stirred reactor, a settler, a mixer-settler and / or a cocurrentwise or countercurrentwise washing column.

[0072] According to another variant, said optional pretreatment step a0) is carried out by filtration. The filtration step makes it possible to remove the inorganic solids, sediments and / or fines contained in the feedstock, in particular the metals, metal oxides and metal chlorides. Use is generally made of a filter, the size (for example the diameter or equivalent diameter) of the pores of which is less than 25 μm, preferably less than or equal to 10 μm, even more preferably less than or equal to 5 μm. According to another variant, use may be made of a filter, the size of the pores of which is less than 25 μm but greater than 5 μm. Use may also be made of a series of filters with different pore sizes, in particular a series of filters having pore sizes decreasing in the direction of the circulation of the feedstock. These filtering media are well known for industrial uses. Cartridge filters or self-cleaning filters are suitable, for example. The solids content can be measured, for example, by the Heptane Insolubles test, ASTM D-3279 method. The content of insolubles in heptane has to be reduced to less than 0.5% by weight, preferably to less than 0.1%.

[0073] According to a specific embodiment, the step of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, optionally followed by a filtration system, the size of the pores of which is less than 2 μm and preferably less than 1 μm.

[0074] According to another specific embodiment, the step of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, followed by an electrostatic precipitation system.

[0075] According to another specific embodiment, the step of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, followed by a system of filter(s) using filtration adjuvants, such as sand or diatomaceous earths.

[0076] According to another variant, said optional pretreatment step a0) is carried out by centrifugation. According to another variant, the pretreatment step a0) comprises a centrifugation and a filtration.

[0077] According to another variant, said optional pretreatment step a0) is carried out by settling. According to another variant, the pretreatment step a0) comprises a settling and a filtration.

[0078] According to another variant, said optional pretreatment step a0) is carried out by gas stripping, thus reducing the content of oxygen in the feedstock. The gas extraction can remove the oxygen (O2) which may be dissolved in the feedstock, thus reducing the probability of formation of free radicals resulting in polymerization in the downstream steps. The process generally involves bringing the feedstock into contact with an extraction gas (for example H2, N2 or a mixture thereof), thus transferring at least one portion of the dissolved oxygen of the feedstock to the extraction gas, followed by the separation of the extraction gas from the feedstock. The volume of extraction gas with respect to the volume of feedstock (the two volumes measured under gas extraction conditions) is generally greater than 1 and preferably at least 3. In specific embodiments, the extraction gas can contain at least 60% (molar percentage) of H2. Any dissolved H2 remaining in the feedstock after the gas extraction step is not a problem, due to the downstream hydrotreating. Preferably, the gas extraction step is finished before any (pre) heating of the feedstock, in order to minimize the potential fouling.

[0079] Said optional pretreatment step a0) generally comprises one or more, preferably several, treatments described above. It can in particular comprise a series of a step of washing with an aqueous solution and / or an adsorption step, followed by a gas stripping step, followed by a filtration step and / or by a centrifugation step. All these steps are preferably carried out before any (pre) heating of the feedstock.

[0080] Said optional pretreatment step a0) thus makes it possible to obtain a pretreated feedstock which subsequently feeds the hydrotreating step a).Hydrotreating Step a)

[0081] According to the invention, the method comprises a step a) carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the pyrolysis feedstock and a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 100° C. and 220° C., a partial pressure of hydrogen of between 1.0 and 3.0 MPa abs. and an hourly space velocity of between 0.05 and 5 h−1, the hydrogen coverage being between 5 and 50 Nm3 of hydrogen per m3 of pyrolysis feedstock, in order to obtain a partially hydrotreated effluent having hydrocarbon compounds with a reduced halogen content.

[0082] Step a) is in particular carried out under mild hydrogen pressure and temperature conditions enabling allowing in particular the removal of the halogens, and in particular of chlorine, in order to make the pyrolysis oil compatible as co-feedstock in the downstream units while retaining as much as possible the diolefins and olefins which can be upgraded in FCC (for the production of propylene).

[0083] The other impurities contained in the pyrolysis oils (metals, silicon, nitrogen, etc.) are not necessarily completely removed during the process according to the invention, although the operating conditions make it possible to remove at least a portion thereof. Step a) thus mainly involves hydrogenation reactions of the halogenated compounds, and to a lesser extent also other hydrotreating reactions well known to those skilled in the art, particularly hydrotreating reactions such as hydrogenation of aromatics, hydrodesulfurization and hydrodenitrogenation, and also the hydrogenation of olefins and diolefins (although it is sought to keep them in the oil).

[0084] Said hydrotreating reaction section is advantageously used at an average hydrotreating temperature (or WABT as defined below) of between 100° C. and 220° C., preferably between 120° C. and 200° C., at a partial pressure of hydrogen of between 1.0 and 3.0 MPa abs., preferably between 1.0 and 2.4 MPa abs., preferably between 1.2 and 2.2 MPa abs., and at an hourly space velocity (HSV) of between 0.1 and 5 h−1, preferably between 0.1 and 2 h−1, preferentially of between 0.1 and 1.0 h−1. The hydrogen coverage in step a) is advantageously of between 5 and 50 Nm3 of hydrogen per m3 of fresh feedstock, and preferably between 10 and 40 Nm3 of hydrogen per m3 of fresh feedstock and in a preferred way between 15 and 30 Nm3 of hydrogen per m3 of fresh feedstock.

[0085] According to the invention, the “average temperature” of a reaction section corresponds to the weight average bed temperature (WABT), which is well known to a person skilled in the art. The average temperature is advantageously determined as a function of the catalytic systems, of the items of equipment, of the configuration of these, which are used. The average temperature (or WABT) is calculated in the following way:WABT=(Tinlet+Toutlet) / 2

[0086] with Tinlet: the temperature of the flow at the inlet of the reaction section and Toutlet: the temperature of the effluent at the outlet of the reaction section. Unless otherwise indicated, the “average temperature” of a reaction section is given at cycle beginning conditions.

[0087] The hourly space velocity (HSV) is defined here as the ratio of the hourly volume flow rate of the feedstock comprising the pyrolysis oil, which has optionally been pretreated, to the volume of catalyst(s).

[0088] The hydrogen coverage is defined as the ratio of the volume flow rate of hydrogen, taken under normal temperature and pressure conditions, relative to the volume flow rate of “fresh” feedstock, that is to say of the feedstock to be treated, which has optionally been pretreated, without taking into account a recycled fraction, at 15° C. (in normal m3, denoted Nm3, of H2 per m3 of feedstock).

[0089] The gas stream comprising hydrogen, which feeds the hydrotreating reaction section, can consist of a supply of hydrogen and / or of recycled hydrogen. Preferably, an additional gas stream comprising hydrogen is advantageously introduced at the inlet of each reactor, in particular operating in series, and / or at the inlet of each catalytic bed starting from the second catalytic bed of the reaction section. These additional gas streams are also referred to as cooling streams. They make it possible to control the temperature in the reactor in which the reactions carried out are generally highly exothermic.

[0090] The gas stream comprising hydrogen may be derived from a fossil source or from a renewable source, for example derived from the gasification of plastic waste, or produced by electrolysis.

[0091] Advantageously, the gas stream comprising hydrogen originates from a compressor used in the refinery to supply another hydrorefining unit using hydrogen, such as a hydrocracking, hydrotreating or hydroconversion unit. The gas stream comprising hydrogen can for example originate from a compressor used to supply the vacuum gas oil (VGO) hydrotreating unit. This has the advantage of dispensing with a dedicated compressor for recycling the hydrogen from step b) and therefore saving on investment costs.

[0092] Optionally, the reaction section of said step a) can also be additionally supplied with a portion of the partially hydrotreated hydrocarbon (recycle) effluent from step b) as described below.

[0093] Preferably, the process according to the invention comprises a hydrotreating step a) carried out in a hydrotreating reaction section, using at least one fixed-bed reactor having n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, preferably between 2 and 5, each comprising at least one hydrotreating catalyst.

[0094] Said hydrotreating reaction section is fed at least with the optionally pretreated pyrolysis feedstock, and a gas stream comprising hydrogen, advantageously at the first catalyst bed of the first reactor in operation. An injection of at least one portion of the pyrolysis feedstock and / or at least one portion of hydrogen between the various catalyst beds is also possible.

[0095] The hydrotreating reaction section using at least one fixed-bed reactor can operate with gas and liquid downflow or upflow.

[0096] Advantageously, the reaction section of said step a) comprises between 1 and 5 reactors, preferably between 2 and 5 reactors, and particularly preferably it comprises 2 reactors. The advantage of a hydrotreating reaction section comprising several reactors lies in an optimized treatment of the feedstock, while making it possible to reduce the risks of clogging of the catalyst bed(s) and thus to avoid shutdown of the unit due to clogging.

[0097] According to this embodiment, the hydrotreating reaction section of step a) comprises two reactors operating in permutable mode, known as PRS for permutable reactor system or else as “lead and lag”. The combination of at least two reactors in PRS mode makes it possible to isolate a reactor, to discharge the spent catalyst, to recharge the reactor with fresh catalyst and to bring said reactor back into service without shutting down the process. The PRS technology is described in particular in patent FR 2 681 871.

[0098] According to another embodiment, said hydrotreating reaction section comprises a single fixed-bed reactor containing n catalyst beds, n being an integer greater than or equal to 1, preferably between 1 and 10, in a preferred way between 2 and 5.

[0099] Advantageously, reactor internals, for example of filter plate type, can be used to prevent the plugging of the reactor(s). An example of a filter plate is described in patent FR 3 051 375.

[0100] Preferably, step a) can employ, upstream of the hydrotreating catalyst(s), at least one guard bed containing adsorbents of alumina, silica, silica-alumina, zeolite and / or active carbon type optionally containing metals from group VIB and / or VIII. Use may also be made of a series of guard beds with particles of different diameters, in particular a series of guard beds having decreasing diameters in the direction of the circulation of the feedstock (also referred to as “grading”).

[0101] Advantageously, said hydrotreating catalyst comprises a support, preferably a mineral support, and a hydrogenating-dehydrogenating function.

[0102] According to a variant, the hydrogenating-dehydrogenating function comprises in particular at least one group VIII element, preferably chosen from nickel and cobalt, and at least one group VIB element, preferably chosen from molybdenum and tungsten. According to this variant, the total content, expressed as oxides, of the metal elements from groups VIB and VIII is preferably between 1% and 40% by weight, preferentially from 5% to 30% by weight, relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO respectively. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3 and WO3 respectively.

[0103] The weight ratio, expressed as metal oxide, of the group VIB metal (or metals) relative to the group VIII metal (or metals) is preferably between 1 and 20 and in a preferred way between 2 and 10.

[0104] According to this variant, the reaction section of said step a) comprises, for example, a hydrotreating catalyst comprising between 0.5% and 12% by weight of nickel, preferably between 0.9% and 10% by weight of nickel (expressed as nickel oxide NiO relative to the weight of said catalyst), and between 1% and 30% by weight of molybdenum, preferably between 3% and 20% by weight of molybdenum (expressed as molybdenum oxide MoO3 relative to the weight of said catalyst), on a preferably mineral support, preferably on an alumina support.

[0105] According to another variant, the hydrogenating-dehydrogenating function comprises, and preferably consists of, at least one group VIII element, preferably nickel. According to this variant, the content of nickel oxides is preferably between 1% and 50% by weight, preferably between 10% and 30% by weight, relative to the weight of said catalyst. This type of catalyst is preferably used in its reduced form, on a preferably mineral support, preferably on an alumina support.

[0106] The support for said hydrotreating catalyst is preferably chosen from alumina, silica, silica-aluminas, magnesia, clays and mixtures thereof. Said support can include dopant compounds, in particular oxides chosen from boron oxide, especially boron trioxide, zirconia, ceria, titanium oxide, phosphorus pentoxide and a mixture of these oxides. Preferably, said hydrotreating catalyst comprises an alumina support, optionally 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 the alumina, and advantageously at least 0.001% by weight, to the total weight of the alumina. When boron trioxide B2O3 is present, its concentration is less than 10% by weight, relative to the weight of the alumina, and advantageously at least 0.001%, relative to the total weight of the alumina. The alumina used can, for example, be a γ (gamma) or η (eta) alumina.

[0107] Said hydrotreating catalyst is for example in the form of extrudates or in the form of beads.

[0108] Very preferably, step a) may also use, in addition to the hydrotreating catalyst(s) described above, at least one hydrotreating catalyst used in step a) comprising less than 1% by weight of nickel and at least 0.1% by weight of nickel, preferably 0.5% by weight of nickel, expressed as nickel oxide NiO relative to the weight of said catalyst, and less than 5% by weight of molybdenum and at least 0.1% by weight of molybdenum, preferably 0.5% by weight of molybdenum, expressed as molybdenum oxide MoO3 relative to the weight of said catalyst, on an alumina support. This catalyst, not highly loaded with metals, can be preferably placed upstream or downstream of the hydrogenation catalyst(s) described above, preferably upstream.

[0109] The preparation of the catalyst for the hydrotreating step a) is known and generally comprises a step of impregnation of the group VIII metals and of the group VIB metals when present, and optionally of the phosphorus and / or boron on the support, followed by drying, and then optionally calcining. The catalyst of step a) can also be a catalyst used in its reduced form, thus involving a reduction step in its preparation.

[0110] Before being used in a step of the process, the catalysts are generally subjected to sulfidation in order to form the active species. Depending on the content of sulfur compounds in the initial feedstock to be treated, a stream containing a sulfiding agent can be injected upstream of the optional pretreatment step a0) or of the hydrotreating step a), preferably upstream of the hydrotreating step a), in order to ensure a sufficient amount of sulfur to form the active species of the catalyst (in sulfide form). This activation or sulfidation step is carried out by methods well known to a person skilled in the art, and advantageously under a sulfo-reductive atmosphere in the presence of hydrogen and hydrogen sulfide. The sulfiding agents are preferably H2S gas, elemental sulfur, CS2, mercaptans, sulfides and / or polysulfides, hydrocarbon cuts having a boiling point of less than 400° C. containing sulfur compounds or any other sulfur-containing compound used for the activation of hydrocarbon feedstocks with a view to sulfiding the catalyst. Said sulfur-containing compounds are advantageously chosen from alkyl disulfides, such as, for example, dimethyl disulfide (DMDS), alkyl sulfides, such as, for example, dimethyl sulfide, thiols, such as, for example, n-butyl mercaptan (or 1-butanethiol), and polysulfide compounds of tert-nonyl polysulfide type. The catalyst can also be sulfided by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfided in situ in the presence of a sulfiding agent and of a hydrocarbon feedstock. Very preferably, the catalyst is sulfided in situ in the presence of the feedstock additivated with dimethyl disulfide. The sulfiding agent can be injected continuously.

[0111] The partially hydrotreated effluent obtained at the end of the hydrogenation step a) is sent, preferably directly, to the washing / separation step b).Separation Step b)

[0112] According to the invention, the treatment process comprises a separation step b), advantageously performed in at least one washing / separation section, fed at least with the partially hydrotreated effluent from step a) and an aqueous solution, to obtain at least a gaseous effluent, an aqueous effluent and a partially hydrotreated hydrocarbon effluent.

[0113] This separation step b) makes it possible in particular to remove the halogens (chlorine) in the form of hydrogen halides (HCl in particular) formed by the reaction of hydrogen ions and halide ions released by the hydrogenation of the halogenated compounds during step a) which dissolve in the aqueous solution.

[0114] The separation step b) is advantageously carried out at a temperature of between 20° C. and 200° C., preferentially between 50° C. and 180° C., in a preferred way between 80° C. and 150° C. Advantageously, the separation step b) is carried out at a pressure close to that used in step a), preferably between 1.0 and 2.0 MPa, so as to facilitate the recycling of hydrogen if need be.

[0115] The separation step can advantageously be carried out by any method known to a person skilled in the art, such as, for example, the combination of one or more separators (drums) and / or one or more stripping columns, it being possible for this or these separator(s) (drum(s)) and / or column(s) to be optionally fed with a stripping gas, for example a hydrogen-rich gas stream. The washing / separation section of step c) can, at least partly, be produced from common or separate items of washing and separating equipment.

[0116] Advantageously, the separation step b) comprises an injection of an aqueous solution, preferably an injection of water, into the partially hydrotreated effluent from step a), upstream of the washing / separation section, so as to dissolve some and preferably all of of the hydrogen halides (HCl in particular) and any salts present.

[0117] The aqueous solution may be water. It can also be a basic aqueous solution (by adding NaOH for example). The use of a basic solution makes it possible to neutralize the hydrogen halides and any dissolved salts.

[0118] In one optional embodiment of the invention, the separation step b) comprises the injection of an aqueous solution into the partially hydrotreated effluent from step a), followed by the washing / separation section advantageously comprising a separation phase for obtaining at least one aqueous effluent loaded with hydrogen halides (HCl in particular) and any dissolved salts present, a washed partially hydrotreated effluent and a partially washed gaseous effluent. Said aqueous effluent and the washed partially hydrotreated effluent can then be separated in a knockout drum in order to obtain said washed partially hydrotreated effluent and said aqueous effluent. Said partially washed gaseous effluent can simultaneously be introduced into a washing column where it circulates countercurrent to an aqueous stream, preferably of the same nature as the aqueous solution injected into the partially hydrotreated effluent, which makes it possible to remove, at least some, preferably all, of the hydrochloric acid contained in the partially washed gaseous effluent and to thus obtain said gaseous effluent, preferably essentially comprising hydrogen, and an acidic aqueous stream. Said aqueous effluent resulting from the knockout drum can optionally be mixed with said acidic aqueous stream, and be used, optionally as a mixture with said acidic aqueous stream, in a water recycling circuit for feeding separation step b) with said aqueous solution upstream of the washing / separation section and / or with said aqueous stream in the washing column. Said water recycling circuit can comprise a supply of water and / or of a basic solution and / or a bleed making it possible to discharge the impurities.

[0119] The hydrotreating step a) mainly involves hydrogenation reactions of the halogenated compounds, and to a lesser extent also other hydrotreating reactions such as hydrodenitrogenation, which generates NH3 by hydrogenation of nitrogen compounds, and hydrodesulfurization, which generates H2S by hydrogenation of sulfur compounds.

[0120] When NH3 is present in the partially hydrotreated effluent from step a), the separation step b) also makes it possible to remove ammonium chloride salts, which are formed by reaction between the chloride ions, released by the hydrogenation of the chlorinated compounds in the form of HCl notably during step a), and the ammonium ions, generated by the hydrogenation of the nitrogen compounds in the form of NH3 during step a) by dissolving them in the aqueous solution.

[0121] When H2S is present in the partially hydrotreated effluent from step a), the separation step b) also makes it possible to remove ammonium sulfide ((NH4)2S) salts which are formed by reaction between H2S resulting from the hydrodesulfurization of the sulfur compounds and NH3, by dissolving them in the aqueous solution.

[0122] According to one embodiment, and as a function of the content of chlorine compounds in the initial or pretreated feedstock, a stream containing a nitrogen compound such as ammonia or an amine, for example monoethanolamine, diethanolamine and / or monodiethanolamine can be injected upstream of the hydrotreating step a) so as to ensure a sufficient amount of ammonium ions for combining the chloride ions formed during the hydrotreating step in the form of ammonium chloride salts, thus making it possible to limit the formation of hydrochloric acid and thus to limit the corrosion downstream of the separation section.

[0123] The gaseous effluent obtained on conclusion of step b) advantageously comprises hydrogen, preferably comprises at least 80 vol %, preferably at least 85 vol %, of hydrogen. The gaseous effluent obtained on conclusion of step b) contains very little chlorine, generally at a content of less than 5 ppm by weight of chlorine, which enables it to be sent into a refining unit requiring hydrogen.

[0124] According to one embodiment, said gaseous effluent can at least partly be recycled to the hydrotreating step a), it being possible for the recycling system to comprise a purification section (for example for adsorption of heavy metals such as mercury).

[0125] According to another preferred embodiment, said gaseous effluent can at least partly be recycled upstream of a hydrogen compressor used to supply a hydrorefining unit using hydrogen such as a hydrocracking, hydrotreating or hydroconversion unit of the refinery. Said gaseous effluent can in particular be recycled upstream of a compressor used to supply a vacuum gas oil hydrotreating unit. This has the advantage of being able to dispense with a dedicated compressor for recycling the hydrogen from step b) and therefore saving on investment costs.

[0126] As for the partially hydrotreated hydrocarbon liquid effluent from step b) and according to one variant, a portion of the partially hydrotreated hydrocarbon effluent from step b) can be recycled upstream of step a). The recycling of a portion of the partially hydrotreated hydrocarbon effluent from step b) to or upstream of step a) advantageously makes it possible, on the one hand, to dilute the impurities and, on the other hand, to control the temperature in step a) in which the reactions involved can be highly exothermic. Diluting the impurities makes it possible to limit undesirable reactions such as the polymerization of diolefins (formation of gum) and / or the formation of coke.

[0127] Advantageously, the amount of the partially hydrotreated hydrocarbon effluent from step b) that is recycled, i.e. the fraction of product obtained that is recycled, is adjusted so that the weight ratio of the recycle stream from step b) to the feedstock comprising a pyrolysis oil, i.e. the feedstock to be treated feeding the overall process, is less than or equal to 10, preferably less than or equal to 7, and preferentially greater than or equal to 0.001, preferably greater than or equal to 0.01 and in a preferred way greater than or equal to 0.1. Preferably, the amount of the partially hydrotreated hydrocarbon effluent from step b) that is recycled is adjusted so that the weight ratio of the recycle stream to the feedstock comprising a pyrolysis oil is between 0.01 and 10, preferably between 0.1 and 7 and particularly preferably between 0.2 and 5. This recycle ratio makes it possible in particular to control the rise in the temperature in step a). This is because, when the recycle ratio is high, the rate of dilution of the feedstock is high, and the rise in temperature at the beginning of the reaction section of step a) is thus controllable by the dilution effect. The injection of the partially hydrotreated hydrocarbon effluent from step b) can be carried out at the first catalyst bed of the reaction section of step a) or between the various catalyst beds. When the hydrotreating reaction section of step a) comprises two reactors operating in permutable mode, at least one portion of the partially hydrotreated hydrocarbon effluent from step b) can be recycled between the two reactors.

[0128] According to another preferred embodiment, the partially hydrotreated hydrocarbon effluent from step b) is sent in part and preferably completely, directly to the inlet of a refinery unit such as an FCC unit or units using hydrogen such as a hydrocracking, hydrotreating or hydroconversion unit as a co-feedstock. This has the advantage of not needing a recycle compressor.

[0129] Said partially hydrotreated hydrocarbon effluent from step b) thus obtained by treatment according to steps a) and b) of the process of the invention has a composition compatible with being introduced as co-feedstock into an FCC unit or a hydrorefining unit, with a petroleum feedstock and / or a feedstock derived from biomass.

[0130] The partially hydrotreated hydrocarbon effluent from step b) is in particular an effluent with a reduced content of halogenated compounds, and in particular of chlorine.

[0131] Preferably, at least 50%, and more preferably at least 75% of the halogenated compounds of the initial feedstock are removed during steps a) and b).

[0132] Preferably, at least 80%, and more preferentially at least 90%, of the olefins are retained during step a).

[0133] Preferably, at least 25%, and more preferentially at least 40% of the diolefins are retained during step a).

[0134] The other impurities contained in the pyrolysis oils (metals, silicon, nitrogen, etc.) are not necessarily completely removed during steps a) and b) of the process according to the invention, although the operating conditions make it possible to remove at least a portion thereof. Specifically, the pyrolysis oil, which is the partially hydrotreated hydrocarbon effluent, does not need to be fully hydrotreated to be able to be introduced into the FCC refining or hydrorefining units downstream, it does not in particular need to undergo further hydrotreatment carried out at higher temperature and / or pressure prior to being introduced into a downstream unit. The remaining impurities will possibly be converted or removed in downstream units, the residual contents of impurities being compatible with these units.

[0135] Preferably, at least 50% and more preferentially at least 75% of the metal elements of the initial feedstock are removed during steps a) and b).

[0136] Generally, at most 50%, and more preferentially at most 25%, of the sulfur compounds in the initial feedstock are removed during steps a) and b).

[0137] Preferably, at least 25%, and more preferentially at least 50% of the oxygen compounds of the initial feedstock are removed during steps a) and b).

[0138] Generally, at most 30%, and more preferentially at most 15%, of the nitrogen compounds of the initial feedstock are removed during steps a) and b).

[0139] The content of heavy metals such as mercury, arsenic, zinc and lead remains essentially unchanged.

[0140] The contents are given as relative concentrations by weight, percentages (%) by weight, part(s) per million (ppm) by weight or part(s) per billion (ppb) by weight, relative to the total weight of the stream under consideration.Step c) of FCC or Hydrorefining

[0141] According to the invention, the process comprises a step c) of fluid catalytic cracking or hydrorefining of a petroleum feedstock and / or a feedstock resulting from biomass conversion in which at least one portion of the partially hydrotreated hydrocarbon effluent from step b) is introduced as co-feedstock, said partially hydrotreated hydrocarbon effluent from step b) being introduced without first undergoing another hydrotreating step carried out at higher temperature and / or pressure than the temperature and / or pressure of step a), said mixture of said petroleum feedstock and / or said feedstock resulting from biomass conversion and the partially hydrotreated hydrocarbon effluent from step b) having a halogen content of less than or equal to 10 ppm by weight.

[0142] Owing to the hydrotreating step a) making it possible to release the halogenated compounds (for example chlorine) mainly in gaseous form (hydrogen halides of HCl type in particular), followed by the washing / separation step b) making it possible to dissolve and remove the hydrogen halides, the partially hydrotreated hydrocarbon effluent from step b) has a content of halogenated compounds that is reduced enough to be able to inject it as co-feedstock into a unit for fluidized-bed cracking, hydrocracking, hydrotreating or hydroconversion of petroleum feedstocks and / or feedstocks resulting from biomass conversion.

[0143] It is in fact chlorine which is generally the limiting contaminant for treating pyrolysis oils in existing units. Chlorine, even at a low content (<10 ppm, or even <5 ppm by weight), is responsible for corrosion (in the form of HCl) which can occur in existing units, the metallurgy of which is generally not designed to withstand chlorine levels of greater than 10 ppm, or even 5 ppm by weight in the feedstock.

[0144] The partially hydrotreated hydrocarbon effluent from step b) is introduced into the unit for fluid catalytic cracking or hydrorefining of a petroleum feedstock and / or a feedstock resulting from biomass conversion in an amount such that the content of chlorine in the mixture of petroleum feedstock and / or feedstock resulting from biomass conversion and the partially hydrotreated hydrocarbon effluent from step b) is less than or equal to 10 ppm by weight, preferably less or equal to 5 ppm weight.

[0145] Generally, the weight ratio of the flow rate of the partially hydrotreated hydrocarbon effluent from step b) (pyrolysis oil) to the flow rate of petroleum feedstock and / or feedstock resulting from biomass conversion introduced into the unit of step c) in the process according to the invention is generally less than 1, and preferably between 0.01 and 0.9, and preferably between 0.02 and 0.5.

[0146] When the content of halogenated compounds is greater than 10, or even 5 ppm by weight in the partially hydrotreated hydrocarbon effluent from step b), the content of 10, or even 5 ppm of chlorine can be achieved by dilution at the inlet of the unit with the petroleum feedstock and / or feedstock resulting from biomass conversion.

[0147] During step c), the partially hydrotreated effluent from step b) is introduced as co-feedstock into a fluid catalytic cracking unit or into a hydrorefining unit using hydrogen, such as a hydrotreating, hydrocracking or hydroconversion unit, with a petroleum feedstock and / or a feedstock resulting from biomass conversion. Preferably, the partially hydrotreated effluent from step b) is injected as co-feedstock into a fluid catalytic cracking unit.

[0148] The petroleum feedstock used in the fluid catalytic cracking unit or in the hydrorefining unit can be chosen from gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, waste oils, deasphalted residues or crudes, petroleum feedstocks originating from thermal or catalytic conversion processes, or mixtures of such feedstocks.

[0149] The feedstock derived from biomass used in the fluid catalytic cracking unit or in the hydrorefining unit can be chosen from vegetable oils, oils from algae or algal oils, fish oils, waste edible oils, and fats of vegetable or animal origin; fatty acid methyl esters of vegetable and / or animal origin, fatty acid methyl esters from waste edible vegetable oils, feedstocks originating from thermal or catalytic biomass conversion processes, or mixtures of such feedstocks. It may in particular be a feedstock as described in the pyrolysis oil feedstock section above.FCC

[0150] The fluid catalytic cracking (FCC) process is widely used in the refining industry for converting atmospheric gas oil, vacuum gas oil and atmospheric residues, a lignocellulosic feedstock or more generally a feedstock resulting from biomass, taken alone or as a mixture, into high-octane gasoline, light fuel oil, heavy fuel oil, light gas rich in olefins (propylene, butylene) and coke. The FCC unit uses a high-activity zeolite catalyst to crack heavy hydrocarbon molecules. A conventional FCC unit is used. For example, a summary description of catalytic cracking (the first industrial use of which goes back to 1936 (Houdry process) or to 1942 for the use of a fluidized bed catalyst) will be found in Ullmann's Encyclopedia of Industrial Chemistry, Volume A 18, 1991, pages 61 to 64. The choice of the catalyst and of the operating conditions depends on the products desired as a function of the feedstock treated, as is, for example, described in the paper by M. Marcilly, pages 990-991, published in the revue de l'institut français du pétrole [Review of the French Institute of Petroleum], November-December 1975, pages 969-1006.

[0151] The fluid catalytic cracking step c) is generally carried out in a fluid catalytic cracking reaction section in a substantially vertical reactor either in upflow (riser) mode or in downflow (downer) mode in the presence of a feedstock chosen from an atmospheric gas oil, a vacuum gas oil, an atmospheric residue and a feedstock derived from biomass and a zeolite catalyst at a reactor temperature between 450° C. and 600° C. with a contact time in the reactor of less than 1 minute, often of 0.1 to 50 seconds.

[0152] A conventional zeolite catalyst comprising a matrix, optionally an additive and at least one zeolite is typically used in the FCC process. The amount of zeolite is variable but is usually from 3% to 60% by weight, often from 6% to 50% by weight, and most often from 10% to 45% by weight, relative to the weight of the catalyst. The zeolite is usually dispersed in the matrix. The amount of additive is usually from 0% to 30% by weight and often from 0% to 20% by weight, relative to the weight of the catalyst. The amount of matrix represents the balance to 100% by weight. The additive is generally chosen from the group formed by the oxides of metals from Group IIa of the Periodic Table of the Elements, such as, for example, magnesium oxide or calcium oxide, rare-earth metal oxides and titanates of metals from Group IIa. The matrix is generally a silica, an alumina, a silica-alumina, a silica-magnesia, a clay or a mixture of two or more of these products. The most commonly used zeolite is zeolite Y.Hydrorefining

[0153] Hydrorefining processes using hydrogen for hydrorefining petroleum feedstocks and / or feedstocks resulting from biomass conversion are known to those skilled in the art and include processes such as hydrotreating, hydrocracking or hydroconversion.Hydrotreatment

[0154] The term “hydrotreating”, commonly referred to as “HDT”, refers to an operation, the main aim of which is to remove impurities, such as sulfur, nitrogen, oxygen, halides and traces of metals, from the feedstock and to saturate olefins and / or to stabilize free radicals of hydrocarbons by reacting them with hydrogen rather than by leaving them to react with themselves. The main aim is not to change the boiling point range of the feedstock. Thus, the hydrotreating comprises in particular hydrodesulfurization (commonly known as “HDS”) reactions, hydrodenitrogenation (commonly known as “HDN”) reactions and hydrodemetallization (commonly known as “HDM”) reactions, accompanied by hydrogenation, hydrodeoxygenation (commonly known as “HDO”), hydrodearomatization, hydroisomerization and hydrodealkylation reactions. Hydrotreating is usually performed using a fixed-bed reactor, although other reactors can also be used for hydrotreating, for example an ebullated-bed hydrotreating reactor.

[0155] The feedstocks employed in the hydrotreating process are, for example, gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, waste oils, deasphalted residues or crudes, feedstocks originating from thermal or catalytic conversion processes, lignocellulosic feedstocks or, more generally, feedstocks derived from biomass, taken alone or as a mixture. The feedstocks which are treated, and in particular those mentioned above, generally contain heteroatoms, such as sulfur, oxygen and nitrogen, and, for the heavy feedstocks, they usually also contain metals.

[0156] A hydrotreating process particularly suitable for introducing the partially hydrotreated pyrolysis oil according to the process according to the invention is a process for hydrotreating a vacuum gas oil, diesel, kerosene or gasoline feedstock and / or a feedstock derived from biomass chosen from vegetable oils, oils from algae or algal oils, fish oils, waste edible oils, and fats of vegetable or animal origin.

[0157] The operating conditions used in the processes implementing the reactions for hydrotreating feedstocks described above are generally as follows: the average temperature is advantageously between 180° C. and 450° C. and preferably between 250° C. and 440° C., the pressure is advantageously between 0.5 and 30 MPa and preferably between 1 and 18 MPa, the hourly space velocity is advantageously between 0.1 and 20 h−1 and preferably between 0.2 and 5 h−1, and a hydrogen coverage of between 50 and 5000 Nm3, preferably between 80 and 2000 Nm3, of hydrogen per m3 of feedstock. The definitions of the average temperature (WABT), of the HSV and of the hydrogen coverage correspond to those described above.

[0158] Conventional hydrotreating catalysts generally comprise an oxide support and an active phase based on metals from groups VIB and VIII in their oxide forms and also phosphorus. The group VIB metal present in the active phase of the catalyst is preferentially chosen from molybdenum and tungsten. The group VIII metal present in the active phase of the catalyst is preferentially chosen from cobalt, nickel and the mixture of these two elements. The active phase of the catalyst is preferably chosen from the group formed by the combination of the elements nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten and nickel-cobalt-molybdenum, and very preferably the active phase consists of cobalt and molybdenum, of nickel and molybdenum, of nickel and tungsten or of a nickel-molybdenum-tungsten combination.

[0159] The content of group VIII metal is between 1% and 10% by weight, preferably between 1.5% and 9% by weight and more preferably between 2% and 8% by weight, expressed as group VIII metal oxide, relative to the total weight of the catalyst. The content of group VIB metal is between 1% and 40% by weight, preferably between 1% and 35% by weight and more preferably between 2% and 30% by weight, expressed as group VIB metal oxide, relative to the total weight of the catalyst. The group VIII metal to group VIB metal molar ratio of the fresh catalyst is generally between 0.1 and 0.8, preferably between 0.15 and 0.6.

[0160] Optionally, the hydrotreating catalyst can additionally exhibit a phosphorus content generally of between 0.1% and 20% by weight of P2O5, relative to the total weight of fresh catalyst, preferably of between 0.2% and 15% by weight of P2O5, very preferably of between 0.3% and 11% by weight of P2O5. Furthermore, the phosphorus / (group VIB metal) molar ratio is generally between 0.08 and 1, preferably between 0.1 and 0.9 and very preferably between 0.15 and 0.8.

[0161] The oxide support of the hydrotreating catalyst is usually a porous solid chosen from the group consisting of: aluminas, silica, silica-aluminas or else titanium or magnesium oxides, used alone or as a mixture with alumina or silica-alumina. According to a particularly preferred alternative form, the oxide support consists of alumina, silica or silica-alumina.

[0162] The catalyst can also additionally comprise at least one organic compound containing oxygen and / or nitrogen and / or sulfur before sulfidation. Such additives are known. Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide function or else compounds including a furan ring or else sugars. The content of organic compound(s) containing oxygen and / or nitrogen and / or sulfur on the catalyst is between 1% and 30% by weight, preferably between 1.5% and 25% by weight and more preferably between 2% and 20% by weight, relative to the total weight of the catalyst.Hydrocracking

[0163] A hydrocracking process makes it possible to convert petroleum fractions, in particular vacuum distillates (VDs), into lighter and more upgradable products (gasoline, middle distillates). Other reactions, such as the hydrogenation of olefins or aromatics, hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, and the like, are also performed.

[0164] The hydrocracking is usually carried out using a fixed-bed reactor.

[0165] The feedstock used in a hydrocracking process is generally a hydrocarbon feedstock in which at least 50% by weight of the compounds have an initial boiling point above 300° C. and a final boiling point below 650° C. It can be chosen from HCOs (Heavy Cycle Oils (heavy gas oils resulting from a catalytic cracking unit)), vacuum distillates, for example gas oils resulting from the direct distillation of crude oil or from conversion units, such as catalytic cracking units, cokers or visbreaking units, feedstocks originating from units for the extraction of aromatics, lubricating oil bases or resulting from the solvent dewaxing of lubricating oil bases, distillates originating from processes for the fixed-bed or ebullated-bed desulfurization or hydroconversion of atmospheric residues and / or vacuum residues and / or deasphalted oils, or else the feedstock can be a deasphalted oil or comprise vegetable oils or else originate from the conversion of feedstocks resulting from biomass. It can also be paraffins from the Fischer-Tropsch process. Said hydrocarbon feedstock treated according to the hydrocracking process of the invention can also be a mixture of said abovementioned feedstocks. Preferably, the feedstock is a vacuum distillate.

[0166] A hydrocracking process particularly suitable for introducing the partially hydrotreated pyrolysis oil according to the process according to the invention is a process for hydrotreating a vacuum gas oil feedstock.

[0167] The hydrocracking processes are generally carried out at an average temperature of between 250° C. and 480° C., advantageously between 320° C. and 450° C., preferably between 330° C. and 435° C., under a pressure of between 2 and 25 MPa, preferably between 3 and 20 MPa, the hourly space velocity of the feedstock relative to the volume of each catalyst (HSV) is advantageously between 0.1 and 40 h−1, preferably between 0.2 and 12 h−1, very preferably between 0.4 and 6 h−1, and a hydrogen coverage of between 50 and 5000 Nm3, preferably between 100 and 2000 Nm3, of hydrogen per m3 of feedstock. The definitions of the average temperature (WABT), of the HSV and of the hydrogen coverage correspond to those described above.

[0168] The processes for the hydrocracking of vacuum distillates cover the pressure and conversion ranges extending from mild hydrocracking to high-pressure hydrocracking. Mild hydrocracking is understood to mean a hydrocracking which results in moderate conversions, generally of less than 40%, and which operates at low pressure, generally between 2 MPa and 6 MPa.

[0169] The hydrocracking process may be a “one-step” hydrocracking process or a “two-step” hydrocracking process. A “one-step” hydrocracking process comprises, firstly and generally, an exhaustive hydrotreating, the aim of which is to carry out an exhaustive HDN, exhaustive HDS and exhaustive HDA of the feedstock before the latter is sent over the hydrocracking catalyst(s). A “two-step” hydrocracking process comprises a first step, the objective of which is, as in the “one-step” process, to carry out the hydrotreating of the feedstock but also to achieve a conversion of the latter of the order generally of 40% to 60%. The effluent resulting from the first step is subsequently subjected to a separation, generally by distillation, most often referred to as intermediate separation, the objective of which is to separate the conversion products from the unconverted fraction. In the second step of the two-step hydrocracking process according to the invention, only the fraction of the feedstock not converted during the first step is treated.

[0170] The hydrocracking catalysts are of the bifunctional type: they combine an acid function with a hydrogenating / dehydrogenating function. The acid function is provided by porous supports, the surfaces of which generally vary from 150 to 800 m2·g−1 and which exhibit a surface acidity, such as halogenated (in particular chlorinated or fluorinated) aluminas, combinations of boron and aluminum oxides, amorphous or crystalline mesoporous aluminosilicates and zeolites dispersed in an oxide binder. The hydrogenating / dehydrogenating function is provided by the presence of an active phase based on at least one metal from Group VIB and optionally at least one metal from Group VIII of the Periodic Table of the Elements. The commonest formulations are of nickel-molybdenum (NiMo) and nickel-tungsten (NiW) type and more rarely of cobalt-molybdenum (CoMo) type.

[0171] The contents of metals are generally as described for the hydrotreating catalysts.

[0172] The hydrocracking catalysts may also contain phosphorus and / or an organic compound containing oxygen and / or nitrogen and / or sulfur in contents as described for the hydrotreating catalysts.Hydroconversion

[0173] The term “hydroconversion” refers to a process, the main aim of which is to reduce the boiling point range of a feedstock comprising at least 50% of a heavy hydrocarbon fraction having a boiling point of at least 300° C., or of at least 450° C., and in which a substantial portion of the feedstock is converted into products having lower boiling point ranges than those of the starting feedstock. Hydroconversion generally involves the fragmentation of larger hydrocarbon molecules to give smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen to carbon ratio.

[0174] The feedstock used in a hydroconversion process is generally a heavy hydrocarbon fraction containing a portion of at least 50% by weight having a boiling temperature of at least 300° C., preferably at least 350° C., and even more preferably of at least 375° C. Advantageously, the heavy hydrocarbon fraction of the feedstock consists of one or more vacuum residues. The vacuum residues can come directly from crude oil, or from other refining units, such as, among others, the hydrotreating of residues, the hydrocracking of residues or the visbreaking of residues. Preferably, the vacuum residues are vacuum residues resulting from the vacuum distillation column of the primary (straight-run (SR)) fractionation of the crude oil.

[0175] The heavy hydrocarbon fraction of the feedstock can also consist of aromatic cuts extracted from a unit for the production of lubricants, of deasphalted oils resulting from a deasphalting unit (raffinates of the deasphalting unit) or of asphalts resulting from a deasphalting unit (residues of the deasphalting unit).

[0176] The heavy hydrocarbon fraction of the feedstock may also consist of a settling oil or a recycle oil (which typically has a boiling range from 360° C. to 550° C.), for example an FCC fluid catalytic cracking effluent such as a heavy cycle oil (HCO) or a slurry oil (SLO).

[0177] The heavy hydrocarbon fraction comprises, and may consist of, at least one of the following feedstocks, alone or in a mixture: a crude oil, a topped crude oil, an atmospheric residue or a vacuum residue from atmospheric or vacuum distillation of a crude oil (preferably from the primary fractionation of the crude oil), an atmospheric residue or a vacuum residue from atmospheric or vacuum distillation obtained during a direct coal liquefaction process, and preferably is a vacuum residue resulting from the vacuum distillation of a crude oil (preferably resulting from the primary fractionation of the crude oil).

[0178] A hydroconversion process particularly suitable for introducing the partially hydrotreated pyrolysis oil according to the process according to the invention is a process for hydroconversion of a vacuum residue feedstock.

[0179] The hydroconversion processes are generally carried out at an average temperature of between 340° C. and 550° C., more preferentially between 350° C. and 500° C., preferably between 360° C. and 450° C., under a pressure of between 2 and 38 MPa, more preferentially between 5 and 25 MPa, more preferably still between 6 and 20 MPa, the hourly space velocity of the feedstock relative to the volume of each catalyst (HSV) is advantageously between 0.05 and 10 h−1, preferably between 0.1 and 5 h−1, more preferably still between 0.15 and 2 h−1, and more preferably still between 0.15 and 1 h−1, a hydrogen coverage of between 50 and 5000 Nm3, preferably between 100 and 2000 Nm3, and very preferably between 200 and 1000 Nm3, of hydrogen per m3 of feedstock. The definitions of the average temperature (WABT), of the HSV and of the hydrogen coverage correspond to those described above.

[0180] The hydroconversion section may comprise one or more ebullated-bed or hybrid-bed (ebullated bed and entrained bed) reactors, containing at least one supported hydroconversion catalyst, it being possible for the reactors to be arranged in series and / or in parallel, as used for the H-Oil® process, as described, for example, in patents U.S. Pat. No. 4,521,295 or U.S. Pat. No. 4,495,060 or U.S. Pat. No. 4,457,831 or U.S. Pat. No. 4,354,852, in the AlChE paper, Mar. 19-23, 1995, Houston, Texas, paper number 46d, “Second generation ebullated bed technology”, or in chapter 3.5, “Hydroprocessing and Hydroconversion of Residue Fractions”, of the work “Catalysis by Transition Metal Sulphides”, published by Editions Technip in 2013.

[0181] The hydroconversion section may also comprise one or more entrained-bed reactors, also referred to as “slurry” reactors (reactors having three phases—liquid, gas, solid—in which the solid and liquid phases can behave as a homogeneous phase) or moving-bed reactors (reactors having three phases with downward movement of the solid catalyst and upward or downward flow of liquid and of gas) or else fixed-bed reactors (reactors having three phases with downward runoff of liquid feedstock onto a fixed bed of supported catalyst with hydrogen flowing typically simultaneously with the liquid, but possibly countercurrent in some cases).

[0182] The hydroconversion catalyst generally comprises an alumina support and at least one group VIII metal chosen from nickel and cobalt, preferably nickel, and at least one group VIB metal chosen from molybdenum and tungsten, preferably molybdenum. Preferably, the hydroconversion catalyst comprises nickel as group VIII element and molybdenum as group VIB element.

[0183] The contents of metals are generally as described for the hydrotreating catalysts.

[0184] The hydroconversion catalysts may also contain phosphorus and / or an organic compound containing oxygen and / or nitrogen and / or sulfur in contents as described for the hydrotreating catalysts.Analysis Methods Used

[0185] The analysis methods and / or standards used to determine the characteristics of the various streams, in particular of the feedstock to be treated and of the effluents, are known to those skilled in the art. They are in particular listed below in table 1 by way of information. Other methods reputed to be equivalent can also be used, in particular equivalent IP, EN or ISO methods:TABLE 1DescriptionMethodsDensity @ 15° C.ASTM D4052Sulfur ContentISO 20846Nitrogen ContentASTM D4629Acid numberASTM D664Bromine NumberASTM D1159Maleic anhydride value (MAV)MAV method (1)Content of Oxygen-Containing MoleculesCombustion + InfraredContent of ParaffinsUOP990-11Content of Naphthenes and OlefinsUOP990-11Content of AromaticsUOP990-11Content of HalogensASTM D7359Chlorine contentASTM D7536Content of Metals:ASTM D5185PFeSiNaBSimulated distillationASTM D2887(1) MAV method described in the paper: 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. 57-68LIST OF FIGURES

[0186] The particulars of the elements referenced in FIGS. 1 to 2 makes possible a better understanding of the invention, without the latter being limited to the specific embodiments illustrated in FIGS. 1 to 2. The various embodiments presented can be used alone or in combination with one another, without limitation of combination.

[0187] FIG. 1 represents the diagram of a general embodiment of the process of the present invention, comprising:

[0188] a step a) of hydrotreating a pyrolysis oil 1 in the presence of a hydrogen-rich gas 2 and optionally an amine provided by stream 3 and optionally a sulfiding agent provided by stream 4;

[0189] a separation / washing step b) supplied with the partially hydrotreated effluent 5 from the hydrotreating step a) and in the presence of an aqueous solution 6 to obtain at least a gaseous effluent 7, an aqueous effluent 8 and a partially hydrotreated hydrocarbon effluent 9, of which a portion 9a can be recycled to step a);

[0190] a step c) of fluid catalytic cracking or hydrorefining a petroleum feedstock and / or a feedstock resulting from biomass conversion 10 in which at least one portion, and preferably all, of the partially hydrotreated hydrocarbon effluent from step b) 9 is introduced as co-feedstock, said partially hydrotreated hydrocarbon effluent from step b) 9 being introduced without undergoing another hydrotreating step carried out at higher temperature and / or pressure beforehand, so as to increase the yield of the product(s) 11 (notably propylene in the case of FCC) resulting from step c).

[0191] FIG. 2 represents the diagram of a specific embodiment of the process of the present invention which is based on the diagram of FIG. 1. This diagram shows the integration of the process according to the invention in an existing refinery comprising a hydrotreatment of a vacuum gas oil, followed by a separation of the hydrotreated vacuum gas oil then the introduction thereof into an FCC in order to produce, inter alia, gasoline and olefins.

[0192] The hydrotreating step a) and the separation / washing step b) are carried out as described in FIG. 1.

[0193] A vacuum gas oil 12 is introduced into a hydrotreating unit 13 in the presence of fresh hydrogen 14 pressurized by a compressor 15 in order to reach the required pressure. The compressor 15 is also supplied, optionally after a purification step (not shown), with the gaseous effluent 7 resulting from the separation step b) of the process according to the invention which essentially contains hydrogen.

[0194] The hydrogen-comprising stream 2 supplying step a) of hydrotreating the pyrolysis oil of the process according to the invention can come from the compressor 15. This makes it possible to use a single hydrogen compressor.

[0195] The hydrotreated effluent 16 is then subjected to a separation 17 making it possible to recover at least a light cut 18 (gas and naphtha), a middle cut 19 (gas oil) and a hydrotreated vacuum gas oil cut 10.

[0196] The hydrotreated vacuum gas oil cut 10 is then introduced into the catalytic cracking unit of step c), as a mixture with the partially hydrotreated hydrocarbon effluent 9 from step b).

[0197] Only the main steps, with the main streams, are shown in FIGS. 1 and 2, so as to allow a better understanding of the invention. It is clearly understood that all the items of equipment required for the operation are present (drums, pumps, exchangers, furnaces, columns, and the like), even if they are not represented. It is also understood that hydrogen-rich gas streams (supply or recycle streams), as described above, can be injected at the inlet of each reactor or catalyst bed or between two reactors or two catalyst beds.EXAMPLES

[0198] The pyrolysis feedstock treated in the process is a plastic pyrolysis oil (i.e. comprising 100% by weight of said plastic pyrolysis oil) having the characteristics indicated in table 2.TABLE 2Characteristics of the pyrolysis feedstockFeed-DescriptionMethodsUnitstockDensity @ 15° C.ASTM D4052g / cm30.820Sulfur ContentISO 20846ppm by weight320Nitrogen ContentASTM D4629ppm by weight730Acid numberASTM D664mg KOH / g1.5Bromine NumberASTM D1159g / 100 g80Maleic anhydride valueMAV methodmg / 100 g10Content of Oxygen-Combustion +% by weight1.0Containing MoleculesInfraredContent of ParaffinsUOP990-11% by weight45Content of NaphthenesUOP990-11% by weight20Content of OlefinsUOP990-11% by weight25Content of AromaticsUOP990-11% by weight10Content of HalogensASTM D7359ppm by weight97Chlorine contentASTM D7536ppm by weight95Content of Metals:ASTM D5185Pppm by weight10Feppm by weight25Sippm by weight45Nappm by weight2Bppm by weight2Simulated distillationASTM D2887 0%° C.4010%° C.9830%° C.16150%° C.23270%° C.30990%° C.394100% ° C.432

[0199] The pyrolysis feedstock is subjected to a hydrotreating step a) carried out in a fixed-bed reactor and in the presence of hydrogen and an NiMo-on-alumina hydrotreating catalyst under different operating conditions indicated in table 3.TABLE 3Conditions of the hydrotreating step a)Example 1Example 2Example 3(not in(in(inaccor-accor-accor-dance)dance)dance)Average temperature° C.230140140Partial pressure ofMPa332hydrogenabs.H2 / HCNm3 / m3555(Hydrogen coverage byvolume, relative to thevolume of feedstock)HSVh−10.50.50.35(volume flow rate offeedstock / volume ofcatalysts)

[0200] On conclusion of the hydrogenation step a), the degrees of conversion (=(initial concentration−final concentration) / initial concentration) observed for chlorine, diolefins and olefins are indicated in table 4.TABLE 4Conversions of the entities during the hydrotreating step a)Example 1Example 2Example 3(not in(in(inaccor-accor-accor-dance)dance)dance)Degree of conversion%908275of the chlorineDegree of conversion%602112of the diolefinsDegree of conversion%1800of the olefinsH2 consumption% by weight0.180.010.01relative tothe weightof the freshfeedstock

[0201] The effluent from the hydrotreating step a) is subjected to a separation step b): a stream of water is injected into the effluent from the hydrotreating step a); the mixture is then treated in an acid gas washing column and knockout drums.

[0202] The yields of the various fractions obtained after separation are shown in table 5 (the yields correspond to the ratios of the amounts by weight of the various products obtained, relative to the weight of feedstock upstream of the step a), expressed as a percentage and denoted % w / w).TABLE 5Yields of the various products obtained after separationGas fraction (NH3 + H2S + H2O + C1-C4)% w / w2.42Liquid fraction% w / w99.31

[0203] The characteristics of the liquid fraction obtained after the separation step b) are presented in table 6:TABLE 6characteristics of the liquid fractionExample 1Example 2Example 3(not in(in(inaccor-accor-accor-DescriptionMethodsUnitdance)dance)dance)SulfurISO 20846ppm by250279286ContentweightNitrogenASTMppm by725730730ContentD4629weightBromineASTMg / 100 g76.18080NumberD1159MaleicMAVmg / 100 g47.98.8anhydridemethodvalue(1)ChlorineASTMppm by101724contentD7536weightSimulatedASTMdistillationD2887 0%° C.60656310%° C.98999830%° C.16116216050%° C.23223123170%° C.30930830990%° C.394393394100% ° C.432434433

[0204] The effluent from step b) is then mixed with a petroleum feedstock for FCC having a chlorine content of 1 ppm by weight in a weight proportion of 10% oil / 90% petroleum feedstock. A mixture is obtained which contains less than 5 ppm by weight of chlorine (for all examples) which is introduced into a fluid catalytic cracking unit without fear of corrosion problems linked to the chlorine content.

[0205] However, in the cases of examples 2 and 3 according to the invention, the olefins and diolefins are retained, which is advantageous because they are compounds that can be upgraded in FCC for the production of propylene. In addition, less energy (temperatures of step a)) and less hydrogen (H2 consumption) are used according to the process according to the invention.

[0206] Example 3, carried out under very mild temperature and pressure conditions, shows that it is possible to obtain an oil sufficiently stripped of chlorine while retaining the olefins and diolefins as much as possible and while using less pressure (and therefore less energy) than in example 2.

Claims

1. A process for treating a pyrolysis feedstock, comprising a plastic and / or tire and / or solid recovered fuel pyrolysis oil comprising halogenated compounds, said process comprising:a) a hydrotreating step carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the pyrolysis feedstock and a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 100° C. and 220° C., a partial pressure of hydrogen of between 1.0 and 3.0 MPa abs., and an hourly space velocity of between 0.05 and 5 h−1, the hydrogen coverage being between 5 and 50 Nm3 of hydrogen per m3 of pyrolysis feedstock, in order to obtain a partially hydrotreated effluent having hydrocarbon compounds with a reduced halogen content,b) a separation step, fed with the partially hydrotreated effluent from step a) and an aqueous solution in order to obtain at least a gaseous effluent, an aqueous effluent and a partially hydrotreated hydrocarbon effluent, andc) a step of fluid catalytic cracking or hydrorefining of a petroleum feedstock and / or a feedstock resulting from biomass conversion in which at least one portion of the partially hydrotreated hydrocarbon effluent from step b) is introduced as a co-feedstock, said partially hydrotreated hydrocarbon effluent from step b) being introduced without first undergoing another hydrotreating step carried out at higher temperature and / or pressure than the temperature and / or pressure of step a), the mixture of said petroleum feedstock and / or said feedstock resulting from biomass conversion and the partially hydrotreated hydrocarbon effluent from step b) having a halogen content of less than or equal to 10 ppm by weight.

2. The process according to claim 1, in which the weight ratio of the flow of the partially hydrotreated hydrocarbon effluent from step b) to the flow of petroleum feedstock and / or feedstock resulting from biomass conversion introduced in step c) is less than 1.

3. The process according to claim 1, in which the pyrolysis feedstock consists of a plastic and / or tire and / or solid recovered fuel pyrolysis oil.

4. The process according to claim 1, in which the content of halogenated compounds in said pyrolysis feedstock is between 1 and 5000 ppm by weight.

5. The process according to claim 1, in which a stream containing a nitrogen compound and / or a sulfur compound is injected upstream of step a).

6. The process according to claim 1, in which said hydrotreating catalyst of step a) comprises a support chosen from alumina, silica, silica-aluminas, magnesia, clays, and mixtures thereof and a hydrogenating-dehydrogenating function comprising either at least one group VIII element and at least one group VIB element, or at least one group VIII element.

7. The process according to claim 1, further comprising at least one step a0) of pretreating the feedstock comprising a plastic and / or tire and / or SRF pyrolysis oil, the pretreatment step being carried out upstream of step a), and comprises an adsorption step and / or a filtration step and / or a centrifugation step and / or a settling step and / or an electrostatic separation step and / or a step of washing with an aqueous solution and / or a gas stripping step.

8. The process according to claim 1, in which the petroleum feedstock is chosen from gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes, and paraffins, waste oils, deasphalted residues or crudes, petroleum feedstocks originating from thermal or catalytic conversion processes, or mixtures of such feedstocks.

9. The process according to claim 1, in which the feedstock derived from biomass is chosen from vegetable oils, oils from algae or algal oils, fish oils, waste edible oils, fats of vegetable or animal origin, fatty acid methyl esters of vegetable and / or animal origin, fatty acid methyl esters from waste edible vegetable oils, feedstocks originating from thermal or catalytic biomass conversion processes, or mixtures of such feedstocks.

10. The process according to claim 1, in which the reaction section of step a) uses at least two reactors operating in permutable mode.

11. The process according to claim 1, in which the fluid catalytic cracking step c) is carried out in a fluid catalytic cracking reaction section in a substantially vertical reactor either in upflow mode or in downflow mode in the presence of a zeolite catalyst at a reactor temperature of between 450° C. and 600° C. with a contact time in the reactor of less than 1 minute.

12. The process according to claim 1, in which the hydrorefining step c) is a hydrotreating step carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 180° C. and 480° C., a partial pressure of hydrogen of between 0.5 and 25 MPa abs., an hourly space velocity of between 0.1 and 20 h−1, and a hydrogen coverage of between 50 and 5000 Nm3 of hydrogen per m3 of feedstock.

13. The process according to claim 1, in which the hydrorefining step c) is a hydrocracking step carried out in a hydrocracking reaction section comprising at least one hydrocracking catalyst, said hydrocracking reaction section being fed with a gas stream comprising hydrogen, said hydrocracking reaction section being used at an average temperature of between 250° C. and 480° C., a partial pressure of hydrogen of between 2 and 25 MPa abs., an hourly space velocity of between 0.5 and 40 h−1, and a hydrogen coverage of between 80 and 5000 Nm3 of hydrogen per m3 of feedstock.

14. The process according to claim 1, in which the hydrorefining step c) is a hydroconversion step carried out in a hydroconversion reaction section comprising at least one hydroconversion catalyst, said hydroconversion reaction section being fed with a gas stream comprising hydrogen, said hydroconversion reaction section being used at an average temperature of between 340° C. and 550° C., a partial pressure of hydrogen of between 2 and 38 MPa abs., an hourly space velocity of between 0.05 and 10 h−1, and a hydrogen coverage of between 50 and 5000 Nm3 of hydrogen per m3 of feedstock.

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