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EP-4735405-A1 - PRODUCTION OF AROMATICS BY CONVERSION OF SYNGAS TO METHANOL AND AROMATIZATION

EP4735405A1EP 4735405 A1EP4735405 A1EP 4735405A1EP-4735405-A1

Abstract

Disclosed is a process for converting a hydrocarbon feedstock, in which a first hydrocarbon feedstock (2) is treated in particular by means of a fractionation train (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 syngas (32) comprising CO and CO 2 ; a methanol synthesis reaction section (50) treats the syngas to produce methanol (51); and an aromatization reaction section (56) at least partially treats the methanol to produce a hydrocarbon effluent (57) comprising aromatic compounds, and to feed the hydrocarbon feedstock with the hydrocarbon effluent.

Inventors

  • JOLY, JEAN-FRANCOIS
  • LAROCHE, CATHERINE
  • CHAHEN, LUDOVIC
  • FRECON, JACINTHE

Assignees

  • IFP Energies nouvelles

Dates

Publication Date
20260506
Application Date
20240613

Claims (15)

  1. 1. A method for converting a first hydrocarbon feedstock comprising aromatic compounds, comprising the following steps: fractionating the first hydrocarbon feedstock (2) in a fractionation train (4-7) to extract at least one cut comprising benzene (22), one cut comprising toluene (23) and one cut comprising xylenes and ethylbenzene (24); separating the cut comprising xylenes and ethylbenzene (24) in a xylene separation unit (10) and producing an extract (39) comprising paraxylene and a raffinate (40) comprising orthoxylene, metaxylene and ethylbenzene; isomerizing the raffinate (40) in an isomerization unit (11) and producing an isomerate (42) enriched in paraxylene; sending the paraxylene-enriched isomerate (42) to the fractionation train (4-7); treating a second hydrocarbon feedstock (30) in a synthesis gas production unit (13; 14) to produce a synthesis gas (32) comprising at least CO and CO2; treating the synthesis gas (32) in a methanol synthesis reaction section (50) to produce methanol (51); treating at least in part the methanol (51) in an aromatization reaction section (56) to produce a hydrocarbon effluent (57) comprising aromatic compounds; and feeding the first hydrocarbon feedstock (2) at least in part with the hydrocarbon effluent (57).
  2. 2. A conversion process according to claim 1, comprising treating methanol (51) in a purification section (52) to separate water (53) and produce purified methanol (55).
  3. 3. Conversion method according to claim 2, in which the purification section (52) is adapted to separate a recycle gas (54) comprising unconverted CO and/or unconverted CO2, and recycle the recycle gas (54) to the inlet of the methanol synthesis reaction section (50).
  4. 4. Conversion method according to any one of the preceding claims, in which the synthesis gas production unit (13; 14) comprises a pyrolysis unit (13) adapted to produce at least one pyrolysis effluent (31) comprising hydrocarbon compounds of 6 to 10 carbon atoms at least partially feeding the first hydrocarbon feedstock (2).
  5. 5. A conversion process according to any preceding claim, comprising treating the hydrocarbon effluent (57) in a separation section (58) to separate water (61) and a light gas purge (60) comprising hydrogen and C1-C2 hydrocarbon compounds, and producing an effluent enriched in aromatic compounds (62) to feed the first hydrocarbon feedstock (2).
  6. 6. Conversion method according to claim 5, in which the separation section (58) is adapted to: separate a recycle effluent (59) comprising at least one of the following compounds: C3-C4 hydrocarbon compounds, C5-C10 non-aromatic hydrocarbon compounds, benzene, toluene; and recycle the recycle effluent (59) to the inlet of the aromatization reaction section (56).
  7. 7. Conversion method according to any one of the preceding claims, in which the synthesis gas production unit (13; 14) comprises: a pyrolysis unit (13) comprising 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 WH 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 WH being the ratio of the volume flow rate of feedstock to the volume of catalyst used; 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; zeolite catalyst comprising and preferably consisting of at least one zeolite selected from ZSM-5, ferrierite, zeolite Beta, zeolite Y, mordenite, ZSM-23, ZSM-57, EU-1, ZSM-11 and preferably the catalyst is a catalyst comprising only ZSM-5; or an oxycombustion unit (14) comprising at least one reactor used in at least one of the following operating conditions: a reactor operating in a fluidized bed; temperature between 500°C and 1000°C; pressure between 0.1 MPa and 3 MPa, preferably between 0.1 MPa and 1 MPa; or a gasification unit comprising at least one gasification furnace used in at least one of the following operating conditions: temperature between 700°C and 1400°C.
  8. 8. Conversion method according to any one of the preceding claims, in which the methanol synthesis reaction section (50) comprises at least one reactor used under at least one of the following operating conditions: temperature between 200°C and 450°C, preferably between 220°C and 400°C, and more preferably still between 250°C and 350°C; pressure between 1 MPa and 12 MPa, preferably between 2 MPa and 10 MPa, and more preferably between 5 MPa and 10 MPa; hydrogen to COx molar ratio in which COx represents CO and CO2, between 3 and 10, preferably between 3 and 7, very preferably between 3 and 5; space velocity of the gas at the reactor inlet between 0.2 g/g ca ta/h and 1 g/g ca ta/h.
  9. 9. Conversion process according to any one of the preceding claims, in which the aromatization reaction section (56) comprises at least one reactor used under at least one of the following operating conditions: temperature between 250°C and 500°C, preferably between 300°C and 450°C, and more preferably still between 350°C and 420°C; 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; space velocity of the gas at the reactor inlet between 0.2 g/g ca ta/h and 1 g/g ca ta/h.
  10. 10. A device for converting a first hydrocarbon feedstock comprising aromatic compounds, comprising: a fractionation train (4-7) adapted to extract at least one cut comprising benzene (22), a cut comprising toluene (23) and a cut comprising xylenes and ethylbenzene (24) from the first hydrocarbon feedstock (2); a xylene separation unit (10) adapted to treat the cut comprising xylenes and ethylbenzene (24) and produce an extract (39) comprising paraxylene and a raffinate (40) comprising orthoxylene, metaxylene and ethylbenzene; an isomerization unit (11) adapted to treat the raffinate (40) and produce an isomerate (42) enriched in paraxylene sent to the fractionation train (4-7); a synthesis gas production unit (13; 14) adapted to process a second hydrocarbon feedstock (30) and produce a synthesis gas (32) comprising at least CO and CO2; a methanol synthesis reaction section (50) adapted to convert CO and CO2 of the synthesis gas (32) into methanol (51); an aromatization reaction section (56) adapted to convert at least in part the methanol (51) into aromatic compounds and produce a hydrocarbon effluent (57) comprising aromatic compounds, and feed the first hydrocarbon feedstock (2) at least in part with the hydrocarbon effluent (57).
  11. 11. A conversion device according to claim 10, comprising a purification section (52) adapted to treat the methanol (51) to separate water (53) and produce purified methanol (55).
  12. 12. Conversion device according to claim 11, wherein the purification section (52) is adapted to separate a recycle gas (54) comprising unconverted CO and/or unconverted CO2, and recycle the recycle gas (54) to the inlet of the methanol synthesis reaction section (50).
  13. 13. Conversion device according to any one of claims 10 to 12, in which the synthesis gas production unit (13; 14) comprises a pyrolysis unit (13) adapted to produce at least one pyrolysis effluent (31) comprising hydrocarbon compounds of 6 to 10 carbon atoms at least partially feeding the first hydrocarbon feedstock (2).
  14. 14. Conversion device according to any one of claims 10 to 13, comprising a separation section (58) adapted to treat the hydrocarbon effluent (57) to separate water (61) and a light gas purge (60) comprising hydrogen and C1-C2 hydrocarbon compounds, and to produce an effluent enriched in aromatic compounds (62) to feed the first hydrocarbon feedstock (2).
  15. 15. Conversion device according to claim 14, in which the separation section (58) is adapted to: separate a recycle effluent (59) comprising at least one of the following compounds: C3-C4 hydrocarbon compounds, non-aromatic C5-C10 hydrocarbon compounds, benzene, toluene, and recycle the recycle effluent (59) to the inlet of the aromatization reaction section (56).

Description

Production of aromatics by conversion of synthesis gas into methanol and aromatization Technical field The invention relates to the production of aromatics for petrochemistry (benzene, toluene, xylenes, i.e., BTX). More particularly, the subject of the invention relates to the production of aromatics (e.g. paraxylene) from the conversion of hydrocarbon compounds (e.g. biomass) into synthesis gas comprising CO and CO2. An aromatic complex (or aromatic compound conversion device) is a device fed with feedstocks predominantly composed of six to ten or more carbon atoms, denoted C6 to C10+ feedstocks. Different sources of aromatic compounds can be introduced into an aromatic complex, the most common being from a catalytic reforming process of naphthas. Within an aromatic complex, regardless of the source of aromatics, benzene and aromatic alkyls (e.g. toluene, paraxylene, orthoxylene) are extracted and then converted into desired intermediates. The products of interest are aromatics with 0 (benzene), 1 (toluene) or 2 (xylenes) methyl groups, and in particular, within xylenes, paraxylene, having the highest market value. The processes of oxycombustion pyrolysis and gasification of hydrocarbon compounds produce a lot of recoverable carbon monoxide (CO) and carbon dioxide (CO2). Pyrolysis processes also produce aromatic compounds. When pyrolysis is catalytic, the combustion of the coke present on the catalyst used in the pyrolysis reactor also produces a significant amount of CO2. Previous technique To date, aromatic complexes can produce benzene, possibly toluene, and xylenes (often paraxylene, sometimes orthoxylene). An aromatic complex generally has at least one catalytic unit exhibiting at least one of the following functions: the isomerization of aromatic compounds with 8 carbon atoms, denoted A8 compounds, to convert orthoxylene, metaxylene, and ethylbenzene into paraxylene; transalkylation to produce xylenes from a mixture of toluene (and optionally benzene) and A9+ compounds such as trimethylbenzenes and tetramethylbenzenes; and the disproportionation of toluene, which produces benzene and xylenes. The aromatic loop makes it possible to produce high-purity paraxylene by adsorption separation or by crystallization, an operation well known in the prior art. This "C8-aromatic loop" includes a step of removing heavy compounds (i.e., C9+) in a distillation column called a "xylene column". The overhead stream from this column, which contains the C8-aromatic isomers (i.e., A8), is then sent to the paraxylene separation process, which is very generally a simulated moving bed adsorption separation (SMB) process to produce an extract and a raffinate, or a crystallization process in which a paraxylene fraction is isolated from the rest of the constituents of the mixture in the form of crystals. The extract, which contains paraxylene, is then distilled to obtain high-purity paraxylene. The raffinate, rich in metaxylene, orthoxylene and ethylbenzene, is treated in a catalytic isomerization unit which gives back a mixture of C8 aromatics, in which the proportion of xylenes (ortho-, meta-, para-xylenes) is practically at thermodynamic equilibrium and the amount of ethylbenzene is reduced. This mixture is again sent to the “xylene column” with the fresh feed. The aromatic complexes producing benzene and paraxylene are overwhelmingly supplied by feedstocks from oil or natural gas. These complexes do not allow the production of bio-sourced aromatics. Another challenge is to valorize carbon in the form of CO and CO2, and in particular bio-sourced carbon, into high added-value compounds. An object of the present invention is to overcome these drawbacks. Summary of the invention In the context described above, a first object of the present description is to overcome the problems of the prior art and to provide a method and a device for producing aromatics for petrochemistry allowing to convert (for example all) of the CO and CO2 produced by pyrolysis, oxycombustion or gasification, into additional aromatic compounds. The CO2 originating from the combustion of the coke present on the catalyst of the pyrolysis process can also be advantageously converted into aromatic compounds. The 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 the aromatic complex, and in particular on the arrangement of several units for converting CO and CO2 into aromatic compounds in two stages: 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. Specifically, the subject matter of the present invention relates to a method and a device using and comprising a unit for converting the mixture of CO and CO2 into methanol followed by a unit for aromatizing the methanol, respectively. Advantageously, the aromatic compounds from the aromatiz