Production of aromatics by conversion of synthesis gas to methanol and aromatization

Abstract

A process for converting a hydrocarbon feedstock, wherein a first hydrocarbon feedstock (2) is processed, in particular, by means of a fractionation train (4-7), a xylene separation unit (10), and an isomerization unit (11), and wherein: a pyrolysis unit (13) or an oxy-combustion or gasification unit (14) processes a second hydrocarbon feedstock (30) to produce a synthesis gas (32) comprising CO and CO2; a methanol synthesis reaction section (50) processes the synthesis gas to produce methanol (51); and an aromatization reaction section (56) processes at least part of the methanol to produce a hydrocarbon effluent (57) comprising aromatic compounds, and to feed the hydrocarbon feedstock with the hydrocarbon effluent. Figure 1 to be published

Claims

Claims

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 isomerate (42) enriched in paraxylene 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. 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. A conversion method according to claim 2, 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).

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. 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 aromatics-enriched effluent (62) for feeding the first hydrocarbon feedstock (2).

6. Conversion method according to claim 5, wherein 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. Conversion process according to any one of the preceding claims, wherein 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 *, preferably between 0.01 h 1 and 5 h *, and very preferably between 0.1 h 1 and 3 h1, the WH is 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;- zeolitic catalyst comprising and preferably consisting of at least one zeolite chosen from ZSM-5, ferrierite, Beta zeolite, Y zeolite, 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 under at least one of the following operating conditions: - temperature between 700°C and 1400°C.

8. Conversion process according to any one 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: - 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 / gcata / h and 1 g / gcata / h.

9. Conversion process according to any one 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: - 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 inlet of the reactor between 0.2 g / gcata / h and 1 g / gcata / h.

10. 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 treat 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 from 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. A conversion device according to claim 10, comprising a purification section (52) adapted to treat the methanol (51) to separate from water (53) and produce purified methanol (55).

12. A 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. 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 charge (2).

14. A 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 produce an effluent enriched in aromatic compounds (62) to feed the first hydrocarbon feedstock (2).

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, C5-C10 non-aromatic hydrocarbon compounds, benzene, toluene, and - recycle the recycle effluent (59) to the inlet of the aromatization reaction section (56).

Images