Production of aromatics by conversion of syngas to methanol and aromatization

Abstract

A process for converting hydrocarbon feedstocks is disclosed in which a first hydrocarbon feedstock (2) is treated in particular by means of a fractionation chain (4-7), a xylene separation unit (10) and an isomerization unit (11), and in which: a pyrolysis unit (13) or an oxycombustion or gasification unit (14) treats a second hydrocarbon feedstock (30) to produce a synthesis gas (32) comprising CO and CO2; a methanol synthesis reaction section (50) treating the synthesis gas to produce methanol (51); and an aromatization reaction section (56) at least partially treating the methanol to produce a hydrocarbon effluent (57) comprising aromatics and feeding the hydrocarbon feedstock with the hydrocarbon effluent.

Description

TECHNICAL FIELD

[0001] The present invention relates to the production of aromatics (benzene, toluene and xylenes, i.e. BTX) for the petrochemical industry. More particularly, the subject matter of the present invention relates to the production of aromatics (e.g. para-xylene) by converting a hydrocarbon compound (e.g. biomass) into a synthesis gas comprising CO and CO2.

[0002] An aromatics complex (or a plant for converting aromatics) is a plant that is fed with a feedstock consisting mainly of 6 to 10 or more carbon atoms, referred to as C6 to C10+ feedstock. Various sources of aromatics can be introduced into the aromatics complex, the most widespread being obtained from catalytic reforming processes of naphtha.

[0003] Within the aromatics complex, benzene and alkylaromatics (e.g. toluene, para-xylene, ortho-xylene) are extracted from whatever source of aromatics, and then converted into desired intermediates. The products of interest are aromatic compounds having 0 (benzene), 1 (toluene) or 2 (xylene) methyl groups, and in particular, among xylenes, para-xylene has the greatest market value.

[0004] Pyrolysis, oxy-combustion and gasification processes of hydrocarbon compounds produce large amounts of upgradable carbon monoxide (CO) and carbon dioxide (CO2). Pyrolysis processes also produce aromatics. When pyrolysis is catalytic, the combustion of coke present on the catalyst used in the pyrolysis reactor also produces a significant amount of CO2. PRIOR ART

[0005] Hitherto, aromatics complexes made it possible to produce benzene, optionally toluene and xylenes (generally para-xylene, sometimes ortho-xylene). An aromatics complex generally has at least one catalytic unit having at least one of the following functions: - isomerization of aromatic compounds containing 8 carbon atoms, represented as A8 compounds, which makes it possible to convert ortho-xylene, meta-xylene and ethylbenzene into para-xylene; - transalkylation, which makes it possible to produce xylenes from toluene (and optionally benzene) and A9+ compounds, such as a mixture of trimethylbenzenes and tetramethylbenzenes; and - disproportionation of toluene, which makes it possible to produce benzene and xylenes.

[0006] The aromatic loop makes it possible to produce high purity para-xylene by adsorptive separation or by crystallization separation, which are operations well known in the prior art. This "C8 aromatic loop" comprises a step of removal of heavy compounds, i.e. C9+ compounds, in a distillation column called "xylene column". The overhead stream from this column, which contains C8 aromatic isomers, i.e. A8 isomers, is then sent to a para-xylene separation process, which is very often a process of separation by simulated moving bed (SMB) adsorption to produce an extract and a raffinate, or a crystallization process in which the para-xylene fraction is separated in crystalline form from the rest of the constituents of the mixture.

[0007] The extract containing para-xylene is then distilled to obtain high purity para-xylene. The raffinate, which is rich in meta-xylene, ortho-xylene and ethylbenzene, is treated in a catalytic isomerization unit which restores a mixture of C8 aromatic compounds in which the proportions of xylenes (ortho-xylene, meta-xylene, para-xylene) are almost at thermodynamic equilibrium and the amount of ethylbenzene is reduced. This mixture is sent again to the "xylene column" together with the fresh feedstock.

[0008] Aromatic complexes producing benzene and para-xylene are very predominantly fed with a feedstock derived from oil or natural gas. These complexes do not make it possible to produce biobased aromatic compounds. Another challenge is to upgrade carbon, and in particular biobased carbon, in the form of CO and CO2 into high added value compounds. It is an object of the present invention to overcome these drawbacks. SUMMARY In the above context, a first object of the present specification is to overcome the problems of the prior art and to provide a process and a plant for producing aromatic compounds for the petrochemical industry which make it possible to convert (e.g. all) CO and CO2 resulting from pyrolysis, oxycombustion or gasification into additional aromatic compounds. CO2 resulting from the combustion of coke present on the catalyst of a pyrolysis process can also be advantageously converted into aromatic compounds.

[0010] The present invention is based on the conversion of carbon monoxide, i.e. CO, and carbon dioxide, i.e. CO2, into aromatic compounds which are introduced into an aromatic complex, and in particular on the provision of a plurality of units to convert CO and CO2 into aromatic compounds in two steps: in a methanol synthesis reactor, and then in a methanol aromatization reactor. The aromatic compounds resulting from the conversion of CO2 are treated within the aromatic loop.

[0011] In particular, the subject of the present invention relates to a process and a plant which respectively use and comprise a unit for converting a mixture of CO and CO2 into methanol, followed by a methanol aromatization unit. Advantageously, the aromatic compounds obtained from the methanol aromatization are introduced into an aromatic complex to be converted into benzene and para-xylene therein.

[0012] According to a first aspect, the above mentioned objects, as well as others, are achieved by a method of converting a first hydrocarbon feedstock comprising aromatic compounds, said method comprising the steps of: - fractionating said first hydrocarbon feedstock in a fractionation train to extract at least one fraction comprising benzene, one fraction comprising toluene and one fraction comprising xylenes and ethylbenzene; - separating said fraction comprising xylenes and ethylbenzene in a xylene separation unit and producing an extract comprising para-xylene and a raffinate comprising ortho-xylene, meta-xylene and ethylbenzene; - isomerizing said raffinate in an isomerization unit and producing an isomerate enriched in para-xylene; - feeding said isomerate enriched in para-xylene to said fractionation train; - processing a second hydrocarbon feedstock in a synthesis gas production unit, such as for example a pyrolysis, oxygen enriched combustion or gasification unit, to produce a synthesis gas comprising at least carbon monoxide (CO) and carbon dioxide (CO2); - processing said synthesis gas in a methanol synthesis reaction section to produce methanol; - processing at least part of the methanol in an aromatization reaction section to produce a hydrocarbon effluent comprising aromatic compounds; and - feeding at least part of said hydrocarbon effluent to said first hydrocarbon feedstock.

[0013] One of the advantages of the present invention is in particular the possibility to convert methanol into aromatic compounds in a single step starting from synthesis gas.

[0014] According to one or more embodiments, the method comprises processing the methanol in a purification section to separate water and produce purified methanol.

[0015] According to one or more embodiments, the purification section is suitable for separating a recycle gas comprising unconverted CO and / or unconverted CO2 and recycling said recycle gas to the inlet of said methanol synthesis reaction section.

[0016] One of the advantages of the present invention is in particular the possibility to convert all synthesis gas by recycling.

[0017] According to one or more embodiments, the synthesis gas production unit comprises a pyrolysis unit suitable for producing at least one pyrolysis effluent comprising hydrocarbon compounds having 6 to 10 carbon atoms, which is at least partially fed to said first hydrocarbon feedstock.

[0018] According to one or more embodiments, the process comprises providing a hydrogen (H2) supply to the synthesis gas by means of a make-up line arranged, e.g. directly, upstream of the methanol synthesis reaction section.

[0019] According to one or more embodiments, the process comprises treating the hydrocarbon effluent in a separation section to separate water and a light gas purge comprising hydrogen and C1-C2 hydrocarbon compounds, and to produce an effluent enriched in aromatic compounds to be fed to the first hydrocarbon feedstock.

[0020] According to one or more embodiments, the separation section is suitable for: - separating a recycle effluent comprising at least one of the following compounds: C3-C4 hydrocarbon compounds, C5-C10 non-aromatic hydrocarbon compounds, benzene, toluene; and - recycling the recycle effluent to the inlet of the aromatization reaction section.

[0021] One of the advantages of the present invention is in particular the conversion of non-aromatic hydrocarbon compounds into aromatic compounds by recycling. One of the advantages of the present invention is in particular the alkylation of benzene and toluene into xylene by recycling.

[0022] According to one or more embodiments, the synthesis gas preparation unit comprises: a pyrolysis unit comprising at least one reactor used at least one of the following operating conditions: - an absolute pressure between 0.1 MPa and 0.5 MPa and an HSV between 0.01 h -1 to 10 h -1 , preferably between 0.01 h -1 to 5 h -1 , and very preferably between 0.1 h -1 to 3 h -1 ; the HSV is the ratio of the volumetric flow of the feedstock to the volume of the catalyst used; - a temperature between 400°C and 1000°C, preferably between 400°C and 650°C, preferably between 450°C and 600°C, and preferably between 450°C and 590°C; - a zeolite catalyst comprising and preferably consisting of at least one zeolite selected from the group consisting of ZSM-5, ferrierite, zeolite beta, zeolite Y, mordenite, ZSM-23, ZSM-57, EU-1 and ZSM-11, and preferably the catalyst is a catalyst comprising only ZSM-5; or an oxycombustion unit comprising at least one reactor used at least one of the following operating conditions: - the reactor is operated as a fluidized bed; - a temperature between 500°C and 1000°C; - a pressure between 0.1 MPa and 3 MPa, preferably between 0.1 MPa and 1 MPa; or a gasification unit comprising at least one gasifier used under at least one of the following operating conditions: - a temperature between 700°C and 1400°C.

[0023] According to one or more embodiments, the methanol synthesis reaction section comprises at least one reactor used under at least one of the following operating conditions: - a temperature between 200°C and 450°C, preferably between 220°C and 400°C, and again more preferably between 250°C and 350°C; - a pressure between 1 MPa and 12 MPa, preferably between 2 MPa and 10 MPa, and more preferably between 5 MPa and 10 MPa; - a hydrogen to CO molar ratio between 3 and 10, preferably between 3 and 7, very preferably between 3 and 5; X wherein CO X represents CO and CO2; - a gas hourly space velocity at the inlet of the reactor between 0.2 g / g cata / h and 1 g / g cata / h.

[0024] According to one or more embodiments, the aromatization reaction section comprises at least one reactor used under at least one of the following operating conditions: - a temperature between 250°C and 500°C, preferably between 300°C and 450°C, and again more preferably between 350°C and 420°C; - a pressure between 0.1 MPa and 1 MPa, preferably between 0.2 MPa and 0.8 MPa, and more preferably between 0.4 MPa and 0.5 MPa; - a gas hourly space velocity at the inlet of the reactor between 0.2 g / g cata / h and 1 g / g cata / h.

[0025] According to a second aspect, the above mentioned objects, as well as others, are achieved by a plant for converting a first hydrocarbon feedstock comprising aromatic compounds, said plant comprising: - a fractionation train suitable for extracting at least one fraction comprising benzene, one fraction comprising toluene and one fraction comprising xylene and ethylbenzene from said first hydrocarbon feedstock; - a xylene separation unit suitable for processing said fraction comprising xylene and ethylbenzene and producing an extract comprising para-xylene and a raffinate comprising ortho-xylene, meta-xylene and ethylbenzene; - an isomerization unit suitable for processing said raffinate and producing an isomerization product enriched in para-xylene, which is sent to said fractionation train; - a synthesis gas production unit, such as for example a pyrolysis unit or an oxygen-rich combustion or gasification unit, suitable for processing a second hydrocarbon feedstock and producing a synthesis gas comprising at least carbon monoxide (CO) and carbon dioxide (CO2); - a methanol synthesis reaction section suitable for converting CO and CO2 of said synthesis gas into methanol; and - an aromatization reaction section suitable for converting methanol at least partially into aromatic compounds and producing a hydrocarbon effluent comprising aromatic compounds, and at least partially feeding said hydrocarbon effluent to said first hydrocarbon feedstock.

[0026] According to one or more embodiments, the apparatus comprises a purification section suitable for processing methanol to separate water and produce purified methanol.

[0027] According to one or more embodiments, the purification section is suitable for separating a recycle gas comprising unconverted CO and / or unconverted CO2 and recycling said recycle gas to the inlet of said methanol synthesis reaction section.

[0028] According to one or more embodiments, the synthesis gas production unit comprises a pyrolysis unit suitable for producing at least one pyrolysis effluent comprising hydrocarbon compounds having from 6 to 10 carbon atoms, which is at least partially fed to said first hydrocarbon feedstock.

[0029] According to one or more embodiments, the apparatus comprises a make-up line for providing a hydrogen supply to said synthesis gas.

[0030] According to one or more embodiments, the apparatus comprises a separation section suitable for processing said hydrocarbon effluent to separate water and a light gas purge comprising hydrogen and C1-C2 hydrocarbon compounds, and to produce an effluent enriched in aromatic compounds to be fed to said first hydrocarbon feedstock.

[0031] According to one or more embodiments, the separation section is suitable for: - separating a recycle effluent comprising at least one of the following compounds: C3-C4 hydrocarbon compounds, C5-C10 non-aromatic hydrocarbon compounds, benzene, toluene; and - recycling said recycle effluent to the inlet of said aromatization reaction section.

[0032] Further features and advantages of embodiments according to the first and second aspects and of the apparatuses and methods according to the above aspects will become apparent on reading the following description, which is given solely by way of example and is not limitative, and on examining the following drawings.

[0033] List of drawings Figure 1 schematic representation of the process according to the application which makes it possible to increase the production of aromatic compounds.

[0034] Description of embodiments Embodiments of the process according to the first aspect and of the apparatus according to the second aspect will now be described in detail. In the following detailed description, numerous specific details are disclosed in order to provide a more thorough understanding of the process. It will be apparent, however, to one skilled in the art, that the process can be practiced without these specific details. In other instances, well-known features are not described in detail in order to avoid unnecessarily complicating the description.

[0035] In the present patent application, the term "comprising" is synonymous with "including" and "containing" and is inclusive or open-ended and does not exclude additional, unrecited elements. It is to be understood that the term "comprising" encompasses the exclusive and closed-ended term "consisting of". Furthermore, in the present specification, a stream comprising essentially or consisting only of compound A corresponds to a stream comprising at least 80% or 90% by weight, preferably at least 95% by weight, very preferably at least 99% by weight of compound A.

[0036] The present application can be defined such that it makes it possible to produce an apparatus and a process for para-xylene and benzene, which comprises a series of unit operations.

[0037] The process and the apparatus according to the present application are characterized in that they comprise and use catalytic units and separation units for producing benzene and para-xylene, which are common in aromatics complexes, known to the person skilled in the art.

[0038] One of the features of the present application can be summarized in the use of carbon monoxide (CO) and carbon dioxide (CO2), i.e. products of pyrolysis, oxycombustion or gasification units of hydrocarbon compounds, to increase the production of aromatic compounds.

[0039] In particular, the combination of a unit for converting a mixture comprising CO and CO2 into methanol and a subsequent unit for the aromatization of methanol and for introducing the aromatic compounds obtained from the aromatization section into an aromatics complex makes it possible to significantly increase the amount of aromatic compounds produced by pyrolysis, oxycombustion or gasification of hydrocarbon compounds and to possibly upgrade all the CO and CO2 produced.

[0040] Reference Figure 1According to one or more embodiments, the process for the conversion of aromatic compounds comprises: - an optional feedstock separation unit 1 for separating a first hydrocarbon feedstock 2 of the aromatics complex into a hydrocarbon fraction having 7 carbon atoms or less (C7-) and an aromatic fraction having 8 carbon atoms or more (A8+); - an optional aromatics extraction unit 3 between the feedstock separation unit 1 and the fractionation train 4-7 for separating aliphatic compounds from the benzene and toluene of the C7- fraction of the feedstock of the complex; - a fractionation train 4-7 downstream of the optional aromatics extraction unit 3 which makes it possible to extract benzene, toluene and xylenes from other aromatic compounds; - an optional transalkylation unit 8 which converts toluene (and optionally benzene) and methylalkylbenzenes, such as trimethylbenzene, into xylenes - advantageously, this unit can also process tetramethylbenzene; - an optional selective hydrogenolysis unit 9 which is suitable for processing a fraction comprising aromatic compounds having 9 and 10 carbon atoms and which produces a hydrogenolysis effluent which is enriched in methyl-substituted aromatic compounds; - an optional separation unit (not shown) for separating the hydrogenolysis effluent and which is arranged (for example directly) downstream of the selective hydrogenolysis unit 9 to produce a plurality of liquid effluent fractions; - a xylene separation unit 10 (for example of the crystallization type or of the SMB type, using molecular sieves and a desorbent, such as toluene) which makes it possible to separate para-xylene from the xylenes and ethylbenzene; - an isomerization unit 11 of the raffinate obtained as effluent of the xylene separation unit 10 to convert, in particular, ortho-xylene, meta-xylene and ethylbenzene into para-xylene; - an optional stabilization column 12 which makes it possible, in particular, to remove more volatile species (for example C5- species) from the aromatics complex, in particular from the effluent of the transalkylation unit 8 and / or from the effluent of the isomerization unit 11; - a synthesis gas production unit, such as a preferably catalytic pyrolysis unit 13, or an oxygen-enriched combustion or gasification unit 14, for processing a second hydrocarbon feedstock 30 to make it possible to produce a synthesis gas 32 comprising CO, CO2 and optionally hydrogen and / or water; - a methanol synthesis reaction section 50 for processing the synthesis gas 32 originating from the pyrolysis unit 13 or from the oxygen-enriched combustion or gasification unit 14 and producing methanol 51; - a first optional make-up line for supplying a hydrogen supply 34 to the synthesis gas 32; - an optional purification section 52 for treating the methanol, separating a water purge 53 and a recycle gas 54 comprising unconverted CO and / or unconverted CO2, and producing purified methanol 55; - an aromatization reaction section 56 for treating the methanol 51 or the purified methanol 55 and producing a hydrocarbon effluent 57 comprising aromatic compounds; - an optional separation section 58 for: treating the hydrocarbon effluent 57; separating water 61; separating a light gas purge 60 comprising hydrogen and C1-C2 hydrocarbon compounds; separating an optional recycle effluent 59 comprising C3-C4 hydrocarbon compounds and / or C5-C10 non-aromatic hydrocarbon compounds and optionally benzene and / or toluene; and producing an aromatic-rich effluent 62.

[0041] According to one or more embodiments, the purification section 52 is adapted for recycling the recycle gas 54 to the inlet of the methanol synthesis reaction section 50.

[0042] According to one or more embodiments, the separation section 58 is adapted for recycling the recycle effluent 59 at least partially to the inlet of the aromatization reaction section 56.

[0043] Advantageously, the hydrocarbon effluent 57 or the aromatic-rich effluent 62 is fed to the first hydrocarbon feedstock 2.

[0044] Reference is made to Figure 1 , the feedstock separation unit 1 treats a first hydrocarbon feedstock 2 of an aromatics complex to separate (e.g. substantially) a compound 16 comprising molecules having 7 carbon atoms or less (C7-), in particular a top fraction containing benzene and toluene, and (e.g. substantially) a bottom fraction comprising aromatic compounds 17 having 8 carbon atoms or more (A8+), which is sent to a xylene column 6. According to one or more embodiments, the feedstock separation unit 1 also separates a first toluene fraction 18 comprising at least 90 wt%, preferably at least 95 wt%, very preferably at least 99 wt% of toluene relative to the total weight of the first toluene fraction 18. According to one or more embodiments, the first toluene fraction 18 is sent to a first column 4 for distilling aromatic compounds, also called benzene column, and / or to a second column 5 for distilling aromatic compounds, also called toluene column.

[0045] According to one or more embodiments, the first hydrocarbon feedstock 2 is a hydrocarbon fraction mainly (i.e. > 50 wt%) containing molecules having a carbon number of 6 to 10 carbon atoms. Such a feedstock can also contain molecules having more than 10 carbon atoms and / or molecules having 5 carbon atoms.

[0046] The first hydrocarbon feedstock 2 to the aromatics complex is rich in aromatic compounds (e.g. > 50 wt%), and contains preferably at least 20 wt% of benzene, preferably at least 30 wt%, very preferably at least 40 wt% of benzene relative to the total weight of the first hydrocarbon feedstock 2. The first hydrocarbon feedstock 2 can result from catalytic reforming of naphtha, or can be the product of a cracking (e.g. steam cracking, catalytic cracking) unit or any other means for producing alkylaromatics.

[0047] According to one or more embodiments, the first hydrocarbon feedstock 2 is at least partially or even entirely biobased. According to one or more embodiments, the first hydrocarbon feedstock 2 is (substantially) derived from a lignocellulosic biomass conversion process. For example, the effluent resulting from the conversion of lignocellulosic biomass can be treated to meet the required specifications of the first hydrocarbon feedstock 2 to exhibit a content of sulfur-based elements, nitrogen-based elements and oxygen-based elements compatible with the aromatics complex.

[0048] According to one or more embodiments, the first hydrocarbon feedstock 2 to the aromatics complex comprises at least 25 wt%, preferably at least 30 wt%, very preferably at least 35 wt% of the hydrocarbon effluent 57 (or the aromatic-enriched effluent 62) and optionally the pyrolysis effluent 31 relative to the total weight of the first hydrocarbon feedstock 2. According to one or more embodiments, the first hydrocarbon feedstock 2 to the aromatics complex consists essentially of the hydrocarbon effluent 57 (or the aromatic-enriched effluent 62) and optionally the pyrolysis effluent 31. According to one or more embodiments, the first hydrocarbon feedstock 2 can comprise a biobased mixture of aromatic and paraffinic compounds and a non-biobased mixture of aromatic and paraffinic compounds (e.g. derived from a catalytic reforming unit).

[0049] According to one or more embodiments, the first hydrocarbon feedstock 2 comprises less than 10 ppm by weight, preferably less than 5 ppm by weight, very preferably less than 1 ppm by weight of elemental nitrogen, and / or less than 10 ppm by weight, preferably less than 5 ppm by weight, very preferably less than 1 ppm by weight of elemental sulfur, and / or less than 100 ppm by weight, preferably less than 50 ppm by weight, very preferably less than 10 ppm by weight of elemental oxygen.

[0050] According to one or more embodiments, the overheads 16 from the feedstock separation unit 1 (optionally mixed with the heavies 21 from the transalkylation unit 8 defined below) are sent directly to the fractionation train, preferably to the benzene column 4 (without treatment by the aromatic extraction unit 3).

[0051] According to one or more embodiments, the overheads 16 from the feedstock separation unit 1 (optionally mixed with the heavies 21 from the transalkylation unit 8 defined below) are sent directly to the fractionation train, preferably to the benzene column 4 (without treatment by the aromatic extraction unit 3).

[0052] According to one or more embodiments, the fractionation train comprises columns 4, 5, 6 and 7 for distilling aromatic compounds, so that the following 5 fractions can be isolated: - a fraction 22 comprising (e.g., essentially) benzene; - a fraction 23 comprising (e.g., essentially) toluene; - a fraction 24 comprising (e.g., essentially) xylenes and ethylbenzene; - a fraction 25 comprising (e.g., essentially) aromatic compounds containing 9 and 10 carbon atoms; - a fraction 26 comprising (e.g., essentially) aromatic compounds, wherein the most volatile species are aromatic compounds containing 10 carbon atoms.

[0053] The benzene column 4 is adapted to: process the aromatic fraction 20, which is (e.g., essentially) a C6-C10 aromatic feedstock (A6+); produce at the top a fraction 22 comprising benzene, which can be one of the desired products at the outlet of the aromatics complex; and produce at the bottom a (e.g., essentially) C7-C10 aromatic outflow 27 (A7+).

[0054] The toluene column 5 is adapted to: process the C7-C10 aromatic outflow 27 (A7+), which is the bottom product from the benzene column 4; produce at the top a fraction 23 comprising toluene, which is directed to the transalkylation unit 8; and produce at the bottom a (e.g., essentially) C8-C10 aromatic outflow 28 (A8+).

[0055] A third column 6 for distilling aromatic compounds, also called xylene column, is suitable for: processing the aromatic fraction 17 of the first hydrocarbon feedstock 2 containing 8 carbon atoms or more (A8+) and optionally the bottom effluent 28 from the toluene column; producing at the top a fraction 24 comprising xylenes and ethylbenzene, which is directed to the xylene separation unit 10; and producing at the bottom an effluent 29 comprising (for example substantially) C9-C10 aromatic compounds (A9+).

[0056] A fourth column 7 for distilling aromatic compounds, also called heavy aromatics column, is optional and is suitable for: processing the bottom effluent 29 from the xylene column; producing at the top a fraction 25 comprising C9-C10 monoaromatics; and producing at the bottom a fraction comprising (for example substantially) aromatic compounds, wherein the most volatile species are aromatic compounds containing 10 carbon atoms 26 (A10+). Preferably, the bottom fraction 26 comprises C11+ compounds.

[0057] In the transalkylation unit 8, the fraction 25 comprising C9-C10 monoaromatics (and / or the hydrogenolysis effluent described below, which is enriched in methyl-substituted aromatic compounds) is mixed with the fraction 23 comprising toluene from the top of the toluene column 5 and is fed to the reaction section of the transalkylation unit 8 to produce xylenes by transalkylation of methyl-deficient aromatic compounds (toluene) and aromatic compounds having an excess of methyl groups (for example trimethylbenzenes and tetramethylbenzenes). According to one or more embodiments, for the production of para-xylene, for example when an excess of methyl groups is observed, benzene is fed to the transalkylation unit 8 (not shown in the figure) in addition to the fraction 25 comprising C9-C10 monoaromatics. Figure 1 According to one or more embodiments, the transalkylation unit 8 directly processes the bottom effluent 29 from the xylene column.

[0058] According to one or more embodiments, the transalkylation unit 8 comprises at least one first transalkylation reactor suitable for being used under at least one of the following operating conditions: - a temperature between 200°C and 600°C, preferably between 350°C and 550°C, and again more preferably between 380°C and 500°C; - a pressure between 2 MPa and 10 MPa, preferably between 2 MPa and 6 MPa, and more preferably between 2 MPa and 4 MPa; - a residence time between 0.5 h -1 and 5 h -1 , preferably between 1 h -1 and 4 h- 1 , and more preferably between 2 h -1 and 3 h -1WHSV between the reactors.

[0059] According to one or more embodiments, the first transalkylation reactor is operated in the presence of a catalyst comprising a zeolite, such as ZSM-5. According to one or more embodiments, the second transalkylation reactor is of the fixed bed type.

[0060] According to one or more embodiments, the effluent from the reaction section of the transalkylation unit 8 is separated in a first separation column (not shown) downstream of said reaction section of the transalkylation unit 8. A fraction 38 comprising at least a part of the benzene and the more volatile species (C6-species) is withdrawn at the top of the first separation column and sent to the optional stabilization column 12, which in particular makes it possible to remove the more volatile species (e.g. C5-species) from the aromatics complex. A heavy fraction 21 from the effluent of the first separation column, which comprises (e.g. essentially) aromatic compounds containing at least 7 carbon atoms (A7+), is optionally recycled to the fractionation train 4-7, for example to the benzene column 4.

[0061] The fraction 24 comprising xylenes and ethylbenzene is treated in a xylene separation unit 10 to produce a fraction or extract 39 comprising para-xylene and a raffinate 40. The extract 39 can be subsequently distilled (e.g. in the case of separation by SMB adsorption), for example by means of an extract column, and then by means of a further toluene column (not shown) in the case where toluene is used as desorbent, to obtain high-purity para-xylene as main product output. The raffinate 40 from the xylene separation unit 10 comprises (e.g. essentially) ortho-xylene, meta-xylene and ethylbenzene, and is fed to the isomerization unit 11.

[0062] According to one or more embodiments, the xylene separation unit 10 also separates a second toluene fraction 41 comprising at least 90 wt%, preferably at least 95 wt%, very preferably at least 99 wt% of toluene relative to the total weight of the second toluene fraction 41. When the xylene separation unit 10 comprises an SMB adsorption unit, the toluene fraction 41 can for example be part of the toluene used as desorbent. According to one or more embodiments, the second toluene fraction 41 is sent to the transalkylation unit 8.

[0063] In the isomerization reaction section of the isomerization unit 11, the isomers of paraxylene are isomerized, while ethylbenzene can be: isomerized to produce a mixture of C8 aromatics, for example if it is desired to produce mainly paraxylene; and / or dealkylated to produce benzene, for example if it is desired to produce both paraxylene and benzene. According to one or more embodiments, the effluent from the isomerization reaction section is sent to a second separation column (not shown) to produce at the bottom an isomerization product 42 enriched in paraxylene, which is preferably recycled to the xylene column 6; and at the top a hydrocarbon fraction 43 containing compounds containing 7 carbon atoms or less (C7-), which is sent to the optional stabilization column 12, for example together with the fraction 38 containing at least part of the benzene and the more volatile species.

[0064] According to one or more embodiments, the isomerization unit 11 comprises a first isomerization zone operating in liquid phase and / or a second isomerization zone operating in gas phase. According to one or more embodiments, the isomerization unit 11 comprises a first isomerization zone operating in liquid phase and a second isomerization zone operating in gas phase. According to one or more embodiments, a first portion of the raffinate 40 is sent to the liquid phase isomerization unit to obtain a first isomerization product, which is directly and at least partially fed to the separation unit 10, and a second portion of the raffinate 40 is sent to the gas phase isomerization unit to obtain an isomerization product, which is sent to the xylene column 6.

[0065] According to one or more embodiments, the gas phase isomerization zone is suitable for use at least one of the following operating conditions: - a temperature greater than 300°C, preferably between 350°C and 480°C; - a pressure less than 4.0 MPa, and preferably between 0.5 MPa and 2.0 MPa; - a space time yield less than 10 h -1 (10 liters / liter / hour), preferably between 0.5 h -1 and 6 h -1 ; - a hydrogen to hydrocarbon molar ratio less than 10, and preferably between 3 and 6; - the presence of a catalyst comprising at least one zeolite having channels whose openings are defined by rings containing 10 or 12 oxygen atoms (10 MR or 12 MR), and a content between 0.1% and 0.3% by weight (in reduced form) of at least one metal from Group VIIIB, with respect to the total weight of the catalyst, including the limits (limits).

[0066] According to one or more embodiments, the liquid phase isomerization zone is suitable for use at least one of the following operating conditions: - a temperature lower than 300°C, preferably between 200°C and 260°C; - a pressure lower than 4 MPa, preferably between 2 MPa and 3 MPa; - a space time yield (STY) lower than 10 h -1 (10 liters / liter / hour), preferably between 2 h -1 and 4 h -1 ; - the presence of a catalyst comprising at least one zeolite having channels whose openings are defined by rings containing 10 or 12 oxygen atoms (10 MR or 12 MR), preferably a catalyst comprising at least one zeolite having channels whose openings are defined by rings containing 10 oxygen atoms (10 MR), and even more preferably a catalyst comprising a ZSM-5 type zeolite.

[0067] The term HSV corresponds to the volume of hydrocarbon feed injected per hour relative to the volume of catalyst loaded.

[0068] According to one or more embodiments, the optional stabilization column 12 produces, at the bottom, a stabilized fraction 44 comprising (e.g. essentially) benzene and toluene, which is optionally recycled to the inlet of the feed separation unit 1 and / or of the aromatic extraction unit 3, and, at the top, a fraction 45 of more volatile species (e.g. C5-), which is withdrawn from the aromatics complex.

[0069] According to one or more embodiments, the selective hydrogenolysis unit 9 is suitable for: - treating mono-aromatic compounds 25 having 9 to 10 carbon atoms; and - producing a hydrogenolysis effluent 46 enriched in methyl-substituted aromatic compounds.

[0070] In particular, the selective hydrogenolysis unit 9 can be suitable for treating aromatic compounds 25 having 9 to 10 carbon atoms by converting one or more alkyl groups (ethyl, propyl, butyl, isopropyl, etc. groups) having at least two carbon atoms attached to the benzene ring into one or more methyl groups (i.e. groups formed by a single CH3 group). The main advantage of the selective hydrogenolysis unit 9 is to increase the content of CH3 groups in the feedstock of the isomerization unit 11 and to reduce the content of ethyl, propyl, butyl, isopropyl, etc. groups, in order to increase the production rate of xylene, and in particular of para-xylene, in said isomerization unit 11.

[0071] According to one or more embodiments, the selective hydrogenolysis unit 9 comprises at least one hydrogenolysis reactor suitable for being used under at least one of the following operating conditions: - a temperature between 300°C and 550°C, preferably between 350°C and 500°C, and even more preferably between 370°C and 450°C; - The pressure is between 0.1 MPa and 3 MPa, preferably between 0.2 MPa and 2 MPa, and more preferably between 0.2 MPa and 1 MPa; - The H2 / HC (hydrocarbon feedstock) molar ratio is between 1 and 10, and preferably between 1.5 and 6; - in 0.1 h -1 Up to 50 h -1 (e.g., 0.5-50 h) -1 Between 0.5 h, preferably 0.5 h -1 Up to 30 h -1 (e.g., 1-30 h) -1 Between 1 h and 1 h, and more preferably between 1 h and 1 h. 1 Up to 20 h -1 (e.g., 2-20 h) -1 5-20 h -1 WHSV between ).

[0072] According to one or more embodiments, the hydrogenolysis reactor operates in the presence of a catalyst comprising at least one metal from Group VIIIB of the periodic table, preferably nickel and / or cobalt, deposited on a porous support comprising at least one crystalline or amorphous refractory oxide having structured or unstructured porosity. According to one or more embodiments, the Group VIIIB metal is nickel. A promoter (Groups VIB, VIIB, VIIIB, IB, IIB) may also be present. This catalyst is supported on a refractory oxide (e.g., alumina or silica) optionally treated with an alkali to neutralize it.

[0073] According to one or more embodiments, the hydrogenolysis reactor is a fixed-bed type, and the catalyst support is in the form of an extrusion. According to one or more embodiments, the hydrogenolysis reactor is a moving-bed type, and the catalyst support is in the form of approximately spherical beads. A moving bed can be defined as a gravity-flow bed, such as those encountered in the catalytic reforming of gasoline.

[0074] According to one or more embodiments, the second hydrocarbon feedstock 30 is a mixture of hydrocarbon compounds having an elemental oxygen content of greater than 1% by weight, preferably greater than 3% by weight, and very preferably greater than 5% by weight relative to the total weight of the second hydrocarbon feedstock 30. According to one or more embodiments, the second hydrocarbon feedstock 30 comprises, or is composed of, one or more components of lignocellulosic biomass or lignocellulosic biomass selected from cellulose, hemicellulose, and lignin.

[0075] The lignocellulosic biomass can consist of wood, agricultural waste or plant waste. Other non-limiting examples of lignocellulosic biomass materials are agricultural residues (straw, corn stover, etc.), forestry residues (products of the first thinning), forestry products, dedicated energy crops (short-rotation coppice), residues from the food processing industry, household organic waste, waste from wood processing plants, waste wood from the construction industry, recycled or non-recycled paper.

[0076] The lignocellulosic biomass can also come from by-products of the paper industry, such as kraft lignin, or from black liquor from pulp manufacturing.

[0077] The lignocellulosic biomass can advantageously be subjected to at least one pre-treatment step before its introduction into the process according to the application. Preferably, the biomass is ground and dried until the desired particle size is obtained. It can be advantageous to obtain a feedstock having a particle size between 0.3 and 0.5 mm. Generally, the particle size of the lignocellulosic biomass is a particle size sufficient to pass through a 1 mm sieve up to a particle size sufficient to pass through a 30 mm sieve.

[0078] According to one or more embodiments, when the second hydrocarbon feedstock 30 is a solid (e.g. a biomass-type feedstock), the second hydrocarbon feedstock 30 is advantageously loaded into a pneumatic entrainment or transport compartment to be entrained by an entrainment fluid into the pyrolysis or oxy-combustion or gasification furnace reactor. Preferably, the entrainment fluid used is gaseous nitrogen. However, it is also envisaged that other non-oxidizing entrainment fluids can be used. Preferably, the synthesis gas produced during the process can be recycled and used as an entrainment fluid. Said synthesis gas consists mainly of non-condensable gaseous effluents comprising at least carbon monoxide (CO) and carbon dioxide (C02), and also advantageously light olefins containing from 2 to 4 carbon atoms. In this way, the cost of carrying out the pyrolysis or oxy-combustion or gasification can be considerably reduced. The second hydrocarbon feedstock 30 can be loaded into a hopper or another device which makes it possible to deliver said feedstock into the entrainment compartment in the appropriate quantity. In this way, a constant quantity of feedstock is delivered into the entrainment compartment.

[0079] The entrainment fluid advantageously delivers the second hydrocarbon feedstock 30 from the entrainment compartment via a feed pipe to the pyrolysis or oxy-combustion reactor or gasifier.

[0080] Generally, the feed pipe is cooled to maintain the temperature of the second hydrocarbon feedstock 30 at the required level before it enters the pyrolysis or oxy-combustion reactor or gasifier. The feed pipe can be cooled by means of a jacket of the pipe, generally an air-cooled or liquid-cooled jacket. However, it is also envisaged that the feed pipe is not cooled.

[0081] According to one or more embodiments, the pyrolysis unit 13 comprises at least one pyrolysis reactor (e.g. a fluidized bed pyrolysis reactor) suitable for use at least at one of the following operating conditions.

[0082] According to one or more embodiments, the pyrolysis step is carried out at a temperature between 400°C and 1000°C, preferably between 400°C and 650°C, preferably between 450°C and 600°C, and preferably between 450°C and 590°C. In particular, the use of a hot regenerated catalyst derived from a catalyst regeneration step can make it possible to provide a temperature range of the reactor.

[0083] The pyrolysis step is also advantageously carried out at an absolute pressure between 0.1 MPa and 0.5 MPa and at an HSV between 0.01 h -1 and 10 h -1 , preferably between 0.01 h -1 and 5 h -1 , and very preferably between 0.1 h -1 and 3 h -1 . The HSV is the ratio of the volumetric flow rate of the feedstock to the volume of catalyst used.

[0084] According to one or more embodiments, the pyrolysis step is catalytic and is carried out in the presence of a catalyst. Preferably, said step is carried out in the presence of a zeolite catalyst comprising and preferably consisting of at least one zeolite selected from the group consisting of ZSM-5, ferrierite, zeolite beta, zeolite Y, mordenite, ZSM-23, ZSM-57, EU-1 and ZSM-11, and preferably said catalyst is a catalyst comprising ZSM-5 only. The zeolite used in the catalyst employed in the catalytic pyrolysis step can advantageously be doped, preferably with a metal selected from the group consisting of iron, gallium, zinc and lanthanum.

[0085] Under these conditions, the second hydrocarbon feedstock 30 will first undergo a rapid pyrolysis in the reactor upon contact with the hot catalyst derived from the regenerator, which acts as a hot carrier in this step. The gases resulting from this pyrolysis will subsequently react on the catalyst, which at this point plays its role as a catalyst to catalyze the reactions leading to the desired chemical intermediates.

[0086] In the pyrolysis unit 13, the second hydrocarbon feedstock 30 is in particular at least partially converted into a pyrolysis effluent 31 comprising hydrocarbon compounds having a carbon number extending from 6 to 10 carbon atoms. The pyrolysis effluent 31 is preferably fed to the first hydrocarbon feedstock 2 of the aromatics complex. The pyrolysis unit 13 also produces a synthesis gas 32 comprising CO, CO2 and optionally hydrogen and by-products 33.

[0087] The product obtained at the end of the pyrolysis step is advantageously recovered in the form of a gaseous effluent comprising the BTX.

[0088] The gaseous effluent comprising the product obtained at the end of the pyrolysis step is then advantageously sent to a fractionation section in order to separate at least the following fractions: - a gaseous fraction of non-condensable gases comprising at least CO and CO2, - a liquid fraction comprising hydrocarbon compounds having a carbon number of between 6 and 10 carbons, referred to as BTX, - a liquid fraction comprising mainly compounds having a number of carbon atoms greater than 9, i.e. at least 50% by weight of C9+ compounds, and - water.

[0089] The gaseous fraction of non-condensable gases can also advantageously comprise light olefins having between 2 and 4 carbon atoms.

[0090] The coked catalyst and the unconverted second hydrocarbon feedstock, commonly referred to as "char", are advantageously withdrawn from the reactor and preferably sent to a stripper in order to remove the possibly adsorbed hydrocarbons by contact with at least one gas selected from steam, an inert gas such as nitrogen and a portion of the gaseous fraction of non-condensable gases produced by the fractionation of the gaseous effluent obtained from the pyrolysis step, and thus prevent their combustion in the regenerator.

[0091] The optionally stripped coked catalyst and unconverted second hydrocarbon feedstock are advantageously sent to a regenerator where the coke and char are combusted by addition of air or oxygen, thus producing a regenerated catalyst and a combustion gas rich in CO2.

[0092] According to one or more embodiments, the regenerated catalyst is advantageously recirculated to the reactor of the pyrolysis step in order to undergo another cycle.

[0093] Advantageously, the pyrolysis step of the process according to the application makes it possible to produce at least 10% by weight, and preferably at least 15% by weight of aromatic compounds relative to the total mass of the reaction product obtained, with a selectivity to BTX of at least 65%, and preferably at least 70%.

[0094] The pyrolysis step also produces at least one BTX fraction (pyrolysis effluent 31) and one gaseous fraction of non-condensable gases (synthesis gas 32) comprising at least CO and CO2.

[0095] In addition to the BTX fraction, the process also makes it possible to obtain a heavier liquid fraction, referred to as "C9+ fraction", which is mainly aromatic, which can advantageously be upgraded in a process external to the process according to the application.

[0096] Preferably, at least part of the gaseous fraction of non-condensable gases is recycled, preferably via a compressor, to the reactor of the pyrolysis step. This gaseous stream then acts as a fluid for entraining the feedstock into said reactor. In this case, a purge of said gaseous recycle effluent is preferably performed, preferably upstream or downstream of said compressor.

[0097] According to one or more embodiments, the pyrolysis effluent 31 is a hydrocarbon fraction containing mainly (i.e. > 50 wt%) molecules having a carbon number of 6 to 10 carbon atoms. The pyrolysis effluent 31 can also contain molecules having more than 10 carbon atoms and / or molecules having 5 carbon atoms. The pyrolysis effluent 31 is rich in aromatic compounds (e.g. > 50 wt%) and contains preferably at least 20 wt% of benzene, preferably at least 30 wt%, very preferably at least 40 wt% of benzene, relative to the total weight of the pyrolysis effluent 31. According to one or more embodiments, the pyrolysis effluent 31 is treated to meet the required specifications of the first hydrocarbon feedstock 2 as described above, to exhibit a content of sulfur-based elements, nitrogen-based elements and oxygen-based elements compatible with an aromatics complex.

[0098] According to one or more embodiments, the synthesis gas 32 (leaving the pyrolysis unit 13) comprises at least part of the gaseous fraction of non-condensable gases and preferably at least partly comprises a combustion gas rich in CO2. According to one or more embodiments, the synthesis gas 32 produced by the pyrolysis unit 13 comprises a mixture containing mainly (e.g. containing at least 50 wt%) CO and CO2. According to one or more embodiments, the synthesis gas 32 comprises at least 20 wt% of CO, preferably at least 30 wt% of CO, very preferably at least 40 wt% of CO (e.g. at least 50 wt% of CO), relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 comprises at least 0.2 wt% of hydrogen, preferably at least 0.5 wt% of hydrogen, very preferably at least 0.8 wt% of hydrogen, relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 at the outlet of the pyrolysis unit 13 contains at least 20 wt% of CO2, relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 at the outlet of the pyrolysis unit 13 contains about 30 wt% (e.g. ± 10 wt%) of CO2, relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 contains methane, ethylene and propylene (e.g. less than 10 wt%) and ethane, propane and water (e.g. less than 3 wt%).

[0099] According to one or more embodiments, the by-product 33 comprises a C9+ fraction consisting mainly of more or less alkylated diaromatic and triaromatic hydrocarbons. This fraction can be upgraded directly into for example marine fuel, or can be subjected to hydrotreatment and / or hydrocracking to improve its properties and to be upgraded into jet fuel or diesel fuel.

[0100] In the oxygen-enriched combustion or gasification unit 14, the second feedstock 30 is converted into a synthesis gas comprising CO, CO2 and optionally water.

[0101] According to one or more embodiments, the oxygen-enriched combustion unit 14 comprises at least one reactor used at least one of the following operating conditions: - the reactor is operated as a fluidized bed; - at a temperature between 500°C and 1000°C; - at a pressure between 0.1 MPa and 3 MPa, preferably between 0.1 MPa and 1 MPa.

[0102] According to one or more embodiments, the oxygen-enriched combustion step is carried out in the presence of / by injection of a gas source comprising at least 80% by weight of oxygen, preferably at least 90% by weight of oxygen, very preferably at least 95% by weight of oxygen, relative to the total weight of the gas source. According to one or more embodiments, the gas source is a pure oxygen source, such as a gas comprising at least 99% by weight of oxygen, preferably at least 99.5% by weight of oxygen, relative to the total weight of the gas source. The temperature of the combustion chamber can be controlled by adjusting the O2 concentration at the inlet of the reactor. This adjustment of the O2 concentration can be carried out by recirculation of the flue gas.

[0103] According to one or more embodiments, the gasification unit 14 comprises at least one gasification furnace used at least one of the following operating conditions: - at a temperature between 700°C and 1400°C.

[0104] According to one or more embodiments, the synthesis gas (leaving the oxygen-enriched combustion or gasification unit 14) 32 comprises a mixture containing mainly (for example at least 50% by weight) CO and CO2. According to one or more embodiments, the synthesis gas 32 comprises at least 70% by weight of CO2, preferably at least 75% by weight of CO2, relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 comprises less than 4% by weight of CO, preferably less than 2% by weight of CO, relative to the total weight of the synthesis gas 32. According to one or more embodiments, the synthesis gas 32 comprises water, for example at least 18% by weight of water, preferably at least 20% by weight of water, relative to the total weight of the synthesis gas 32.

[0105] According to one or more embodiments, hydrogen gas supply 34 fed by a make-up line is added to synthesis gas 32 so that the H2 / (CO+CO2) molar ratio of synthesis gas 32 at the inlet of methanol synthesis reaction section 50 is between 3 and 10, preferably between 3 and 8, preferably between 3 and 7, preferably between 3 and 6, very preferably between 3 and 5. The make-up hydrogen gas can advantageously come from any process producing hydrogen gas, such as a steam reforming process or a catalytic reforming process, water electrolysis, alkane dehydrogenation, and its hydrogen gas purity is typically between 75 vol% and 99.9 vol%. It should be understood that hydrogen gas supply 34 can be provided directly to methanol synthesis reaction section 50 and then mixed with synthesis gas 32.

[0106] In methanol synthesis reaction section 50, synthesis gas 32, preferably enriched with hydrogen gas supply 34, is at least partially converted into methanol and water. The reaction of synthesis of methanol from CO2 and CO is well known to the person skilled in the art (see for example: US5631302, US4238403, EP 3 402 773 and Renewable Energy, 146 (2020), 1192-1203).

[0107] According to one or more embodiments, methanol synthesis reaction section 50 comprises at least one reactor used under at least one of the following operating conditions: - a temperature between 200°C and 450°C, preferably between 220°C and 400°C, and again more preferably between 250°C and 350°C; - a pressure between 1 MPa and 12 MPa, preferably between 2 MPa and 10 MPa, and more preferably between 5 MPa and 10 MPa; - a H2 / CO (CO and CO2) molar ratio between 3 and 10, preferably between 3 and 7, very preferably between 3 and 5; X - a gas hourly space velocity at the inlet of the reactor between 0.2 g / gcata / h and 1 g / gcata / h.

[0108] According to one or more embodiments, the reactors of methanol synthesis reaction section 50 are adapted to operate as a fluidized bed or as a fixed bed, preferably as a fixed bed.

[0109] ​According to one or more embodiments, the methanol synthesis reaction is carried out in the presence of a hydrogenation catalyst. According to one or more embodiments, the catalyst is a catalyst for CO2 hydrogenation. According to one or more embodiments, the catalyst for CO2 hydrogenation comprises copper (for example in the form of an oxide) and optionally at least one promoter selected from the group consisting of Zn, Zr, Si, a1, Ti, Cr, Ga, Ce (for example in the form of an oxide), and optionally a support (for example a refractory oxide such as alumina). According to one or more embodiments, the catalyst for CO2 hydrogenation is of the CuO / ZnO / Al2O3 type. According to one or more embodiments, the catalyst for CO2 hydrogenation comprises 50-75 wt% of CuO, 15-35 wt% of ZnO and 5-20 wt% of Al2O3, relative to the total weight of the catalyst.

[0110] According to one or more embodiments, the synthesis gas 32 can be purified before being introduced into the methanol synthesis reaction section 50. The purification of the synthesis gas aims at removing sulfur and nitrogen containing compounds, halogens, heavy metals and transition metals. The main synthesis gas purification techniques are: adsorption, absorption, catalytic reaction.

[0111] Various purification methods are known to the person skilled in the art; reference can be made, for example, to Oil & Gas Science and Technology - Rev. IFP Energies Nouvelles, 68 (2013), No. 4; and to Applied Energy, 237 (2019), 227-240.

[0112] In the optional purification section 52, the methanol 51 is treated to separate water 53 and a recycle gas 54 comprising unconverted CO and / or unconverted CO2, and to produce purified methanol 55. The recycle gas 54 is preferably recycled to the inlet of the methanol synthesis reaction section 50. The water-methanol separation can be carried out by distillation. According to one or more embodiments, the purified methanol 55 comprises at least 99.1 wt% of methanol. According to one or more embodiments, the water 53 comprises at least 99.99 wt% of water. The water 53 (by-product of the methanol synthesis reaction) is purged and discharged from the process, or sent to an electrolysis cell to produce hydrogen, or used for a biomass pre-treatment operation upstream of the pyrolysis unit 13 or the oxycombustion or gasification unit 14.

[0113] According to the application, the methanol 51 or the purified methanol 55 is sent to an aromatization reaction section 56 to treat the methanol and produce aromatic compounds. According to one or more embodiments, the aromatization reaction section 56 comprises at least one reactor used under at least one of the following operating conditions: - a temperature between 250°C and 500°C, preferably between 300°C and 450°C, and again more preferably between 350°C and 420°C; - a pressure between 0.1 MPa and 1 MPa, preferably between 0.2 MPa and 0.8 MPa, and more preferably between 0.4 MPa and 0.5 MPa; - a gas space velocity at the inlet of the reactor between 0.2 and 1 g / g cata / h.

[0114] According to one or more embodiments, the reactors of the aromatization reaction section 56 are suitable to operate as fluidized beds.

[0115] According to one or more embodiments, the aromatization reaction is carried out in the presence of an aromatization catalyst. According to one or more embodiments, the catalyst is a catalyst for methanol aromatization. According to one or more embodiments, the catalyst for methanol aromatization comprises zinc optionally impregnated on a zeolite (e.g. ZSM-5), optionally arranged on a support (e.g. a refractory oxide, such as alumina). According to one or more embodiments, the catalyst for methanol aromatization is of the Zn-ZSM-5 / AI2O3 type and preferably comprises from 0.1 wt% to 10 wt%, such as from 1 wt% to 5 wt% of Zn, with respect to the total weight of the catalyst. Examples of such catalysts are described in Journal of Catalysis, 394 (2021), 416-428 and Catalysis Today, 233 (2014), 8-13.

[0116] At the outlet of the aromatization reaction section 56, four streams can be separated: - an aromatic compounds-enriched effluent 62, which is mixed with the first hydrocarbon feedstock 2 and sent to the feedstock separation unit 1 ; - a recycle effluent 59 comprising C3-C4 hydrocarbon compounds and / or non-aromatic C5-C10 hydrocarbon compounds, which is recycled to the inlet of the aromatization reaction section 56; - a water stream 61 discharged at the outlet of the aromatization reaction section 58, which can be sent to an electrolytic cell to produce hydrogen, or used for a biomass pre-treatment operation upstream of the pyrolysis unit 13 or of the oxygen-enriched combustion or gasification unit 14; and - a hydrogen and C1-C2 light gas purge 60.

[0117] According to one or more embodiments, the recycle effluent 59 comprises benzene and / or toluene.

[0118] Advantageously, the combination of the methanol synthesis reaction section 50 and the subsequent aromatization section 56 makes it possible to produce additional aromatic compounds from CO and CO2 (products of the pyrolysis unit 13 or of the oxygen-rich combustion or gasification unit 14).

[0119] Thus, the process and the plant according to the present application make it possible to obtain a gain of up to 350% by weight of aromatic compounds, in particular when the CO2 formed by the combustion of the coke present on the pyrolysis catalyst is also treated.

[0120] In the present patent application, the groups of chemical elements are given by default according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor D.R. Lide, 81st edition, 2000-2001). For example, the group VIIIB according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification; the group VIB according to the CAS classification corresponds to the metals of column 6 according to the new IUPAC classification.

[0121] Example Reference method example 1 Reference method example 1 was used to transform a feedstock comprising aromatic compounds obtained from a lignocellulosic biomass conversion process based on catalytic pyrolysis conversion.

[0122] Reference method example 1 was similar to the method shown in Figure 1 except that the transalkylation unit 8 was replaced by a disproportionation unit. In addition, reference method example 1 did not use the following units: - the heavy aromatics column 7; - the selective hydrogenolysis unit 9; - the stabilization column 12; - the methanol synthesis reaction section 50; - the purification section 52; - the separation section 58; and - the aromatization reaction section 56.

[0123] At the inlet of the reference method, the flow rate of the aromatic compounds of the feedstock to be treated was as follows: - benzene: 2.63 t / h; - toluene: 5.64 t / h; - ethylbenzene: 0.15 t / h; and - xylene: 3.56 t / h. That is, a total of 11.98 t / h of aromatic compounds.

[0124] In addition, the pyrolysis reaction section produces CO and CO2 which are not converted into other chemical compounds. The flow rate of CO produced is 22.25 t / h and the flow rate of CO2 is 15.99 t / h. The combustion of the coke present on the pyrolysis catalyst produces 67 t / h of CO2. That is, the total flow rate of un-upgraded CO2 is equal to 82.99 t / h.

[0125] In the reference process, all the toluene is converted into benzene and xylenes by the disproportionation unit. The xylenes of the feedstock and the xylenes produced by disproportionation are isomerized to obtain para-xylene which is separated from the mixture of xylenes at thermodynamic equilibrium at the outlet of the isomerization unit by means of the SMB adsorption unit. This set of unit operations allows, in the best case (at 100% of the theoretical selectivity of each unit operation), the production of the following compounds: - benzene: 5.02 t / h; - para-xylene: 6.96 t / h - total aromatics: 11.98 t / h.

[0126] Example 2 of the process according to the application Example 2 of the process according to the application makes it possible to increase the total amount of aromatics produced, and in particular the amount of para-xylene produced, at the same flow rate of biomass feedstock entering the pyrolysis unit 13 as in the reference process.

[0127] A methanol synthesis reaction section 50 and a purification section 52 have been added compared to the scheme of the reference process, in which the recycled gas 54 (unconverted CO2 + CO) is recycled from the purification section 52 to the inlet of the methanol synthesis reaction section 50. In this example 2, a hydrogen supply 34 is added at the inlet of the methanol synthesis reaction section 50. The water withdrawal 53 also makes it possible to remove the by-product water of methanol synthesis.

[0128] An aromatization reaction section 56, a separation section 58, two withdrawal lines for water 61 and light gas purge gas 60 and a recycling line for sending the recycled effluent 59 to the inlet of the aromatization reaction section 56 have also been added.

[0129] The synthesis gas 32 containing CO and CO2 produced by the pyrolysis unit 13, and the CO2 produced by the combustion of the coke present on the pyrolysis catalyst, are introduced into the methanol synthesis reaction section 50, together with the hydrogen supply 34. At the outlet of the purification section 52, the purified methanol 55 is introduced into the aromatization reaction section 56. At the outlet of the separation section 58: the recycled effluent 59 is recycled to the inlet of the aromatization reaction section 56, the water 61 is withdrawn, the light gas 60 is withdrawn and the effluent enriched in aromatics is sent to the inlet of the aromatics complex.

[0130] The conversion of CO and CO2 by means of this process can be complete. The water formed can advantageously be used in the electrolysis cell upstream of the pyrolysis unit 13 for the biomass pre-treatment operation.

[0131] The overall material balances of the reference process and the process according to the application are compared in Table 1.

[0132] Table 1 .

[0133] Table 1 shows that the implementation according to the application makes it possible to produce significantly more aromatic compounds (44.66 t / h instead of 11.98 t / h). This increase in aromatic compounds essentially involves para-xylene, which increases from 6.96 t / h to 42.55 t / h.

[0134] An amount of water equal to 82.2 t / h is also produced and can be used for the biomass pre-treatment step upstream of the pyrolysis unit.

Claims

1. A method for converting a first hydrocarbon feedstock containing aromatic compounds, comprising the following steps: - Fractionate the first hydrocarbon feedstock (2) in the fractionation chain (4-7) to extract at least one fraction (22) containing benzene, one fraction (23) containing toluene, and one fraction (24) containing xylene and ethylbenzene; - The fraction (24) containing xylene and ethylbenzene is separated in the xylene separation unit (10) to produce an extract (39) containing p-xylene and a raffinate (40) containing o-xylene, m-xylene and ethylbenzene. - The raffinate (40) is isomerized in the isomerization unit (11) to produce an isomerized product (42) enriched with p-xylene; - The isomerized product (42) enriched with p-xylene is fed into the fractionation chain system (4-7); - The second hydrocarbon feedstock (30) is processed in the syngas preparation unit (13; 14) to produce syngas (32) containing at least CO and CO2; - The synthesis gas (32) is processed in the methanol synthesis reaction section (50) to produce methanol (51); - The methanol (51) is at least partially treated in the aromatization reaction section (56) to produce a hydrocarbon effluent (57) containing aromatic compounds; and - The hydrocarbon effluent (57) is fed at least partially into the first hydrocarbon feedstock (2).

2. The conversion method claimed in claim 1, comprising treating the methanol (51) in a purification stage (52) to separate water (53) and produce purified methanol (55).

3. The conversion method claimed in claim 2, wherein the purification section (52) is adapted to separate a recycle gas (54) containing unconverted CO and / or unconverted CO2, and to recycle the recycle gas (54) to the inlet of the methanol synthesis reaction section (50).

4. The conversion method claimed in any of the preceding claims, wherein the syngas preparation unit (13; 14) comprises a pyrolysis unit (13) adapted to produce at least one pyrolysis effluent (31) comprising a hydrocarbon compound having 6 to 10 carbon atoms, the pyrolysis effluent (31) being at least partially fed to the first hydrocarbon feedstock (2).

5. The conversion method claimed in any of the preceding claims, comprising treating the hydrocarbon effluent (57) in a separation section (58) to separate water (61) and a light gas purge gas (60) containing hydrogen and C1-C2 hydrocarbon compounds, and producing an effluent (62) enriched with aromatic compounds to be fed to the first hydrocarbon feedstock (2).

6. The conversion method as claimed in claim 5, wherein the separation segment (58) is suitable for: - Separate recycle effluents (59) containing at least one of the following compounds: C3-C4 hydrocarbons, C5-C10 non-aromatic hydrocarbons, benzene, toluene; and - The recycled effluent (59) is recycled to the inlet of the aromatization reaction section (56).

7. The conversion method as claimed in any of the preceding claims, wherein the syngas preparation unit (13; 14) comprises: The pyrolysis unit (13) includes at least one reactor used under at least one of the following operating conditions: - Absolute pressure between 0.1 MPa and 0.5 MPa and at 0.01 h -1 Up to 10 h -1 Between, preferably within 0.01 h -1 Up to 5 hours -1 Between, and very preferably within 0.1 h -1 Up to 3 hours -1 The HSV is the ratio of the volumetric flow rate of the feedstock to the volume of the catalyst used. - A temperature between 400°C and 1000°C, preferably between 400°C and 650°C, more preferably between 450°C and 600°C, and more preferably between 450°C and 590°C; - A zeolite catalyst comprising at least one zeolite selected from the group consisting of, and preferably composed of, at least one zeolite selected from the group consisting of: ZSM-5, magnesium alkali zeolite, zeolite β, zeolite Y, mordenite, ZSM-23, ZSM-57, EU-1 and ZSM-11, and preferably, the catalyst is a catalyst containing only ZSM-5; or An oxygen-enriched combustion unit (14) comprising at least one reactor used under at least one of the following operating conditions: - The reactor operates as a fluidized bed; - Temperatures between 500℃ and 1000℃; - A pressure between 0.1 MPa and 3 MPa, preferably between 0.1 MPa and 1 MPa; or A gasification unit comprising at least one gasifier used under at least one of the following operating conditions: - Temperatures between 700°C and 1400°C.

8. The conversion method claimed in any of the preceding claims, wherein the methanol synthesis reaction section (50) comprises at least one reactor used under at least one of the following operating conditions: - The temperature is between 200°C and 450°C, preferably between 220°C and 400°C, and even more preferably between 250°C and 350°C; - The pressure is between 1 MPa and 12 MPa, preferably between 2 MPa and 10 MPa, and more preferably between 5 MPa and 10 MPa; - The ratio of hydrogen to CO is between 3 and 10, preferably between 3 and 7, and very preferably between 3 and 5. X molar ratio, where CO X Indicates CO and CO2; - at 0.2 g / g cata / h to 1 g / g cata The gas space velocity at the reactor inlet is between / h.

9. The conversion method claimed in any of the preceding claims, wherein the aromatization reaction section (56) comprises at least one reactor used under at least one of the following operating conditions: - The temperature is between 250°C and 500°C, preferably between 300°C and 450°C, and even more preferably between 350°C and 420°C; - The pressure is between 0.1 MPa and 1 MPa, preferably between 0.2 MPa and 0.8 MPa, and more preferably between 0.4 MPa and 0.5 MPa; - at 0.2 g / g cata / h to 1 g / g cata The gas space velocity at the reactor inlet is between / h.

10. An apparatus for converting a first hydrocarbon feedstock comprising aromatic compounds, comprising: - Fractionation chain (4-7) suitable for extracting at least one fraction (22) containing benzene, one fraction (23) containing toluene and one fraction (24) containing xylene and ethylbenzene from the first hydrocarbon feedstock (2); - Xylene separation unit (10), which is adapted to process the fraction (24) containing xylene and ethylbenzene and produce an extract (39) containing p-xylene and a raffinate (40) containing o-xylene, m-xylene and ethylbenzene. - An isomerization unit (11) adapted to process the raffinate (40) and produce an isomerized product (42) enriched with p-xylene, which is then fed to the fractionation chain (4-7). - Syngas preparation unit (13; 14), which is adapted to process a second hydrocarbon feedstock (30) and produce syngas (32) containing at least CO and CO2; - Methanol synthesis reaction section (50), which is suitable for converting CO and CO2 of the synthesis gas (32) into methanol (51); and - An aromatization reaction section (56) adapted to at least partially convert the methanol (51) into an aromatic compound and produce a hydrocarbon effluent (57) containing the aromatic compound, and to feed at least partially the hydrocarbon effluent (57) into the first hydrocarbon feedstock (2).

11. The conversion apparatus claimed in claim 10, comprising a purification section (52) adapted to process the methanol (51) to separate water (53) and produce purified methanol (55).

12. The conversion apparatus claimed in claim 11, wherein the purification section (52) is adapted to separate a recycle gas (54) containing unconverted CO and / or unconverted CO2, and to recycle the recycle gas (54) to the inlet of the methanol synthesis reaction section (50).

13. The conversion apparatus claimed in any one of claims 10 to 12, wherein the syngas preparation unit (13; 14) comprises a pyrolysis unit (13) adapted to produce at least one pyrolysis effluent (31) comprising a hydrocarbon compound having 6 to 10 carbon atoms, the pyrolysis effluent (31) being at least partially fed to the first hydrocarbon feedstock (2).

14. The conversion apparatus claimed in any one of claims 10 to 13, comprising a separation section (58) adapted to process the hydrocarbon effluent (57) to separate water (61) and a light gas purge gas (60) containing hydrogen and C1-C2 hydrocarbon compounds, and to produce an effluent (62) enriched with aromatic compounds to be fed to the first hydrocarbon feedstock (2).

15. The conversion device as claimed in claim 14, wherein the separation section (58) is adapted to: - Separate recycle effluents (59) containing at least one of the following compounds: C3-C4 hydrocarbons, C5-C10 non-aromatic hydrocarbons, benzene, toluene; and - The recycled effluent (59) is recycled to the inlet of the aromatization reaction section (56).

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