Gas to olefins processes with coproduction of hydrogen

Patent metadata

Field	Value
Publication number	US-11739035-B2
Application number	US-202117915945-A
Country	US
Kind code	B2
Filing date	Mar 29, 2021
Priority date	Mar 30, 2020
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

The present disclosure relates in its first aspect to a process of converting a stream comprising methane into chemicals, said process being remarkable in that it comprises the steps of providing a first stream ( 1, 5, 11 ) comprising methane, providing a second stream ( 79 ) which is a bromine-rich stream, putting into contact said first stream ( 15 ) with said second stream ( 79 ) to obtain a third stream ( 21 ) comprising at least unreacted methane, methyl bromide, dibromomethane, and hydrogen bromide and removing said dibromomethane from said third stream ( 21 ), to produce a dibromomethane stream ( 103 ) and a fourth stream ( 27 ) comprising unreacted methane, methyl bromide and hydrogen bromide; wherein the fourth stream ( 27 ) is converted into chemicals. In its second aspect, the present disclosure concerns an installation for carrying out the process of the first aspect.

First claim

The invention claimed is:

1. A process for converting a stream comprising methane into chemicals, said process being characterized in that it comprises the following steps:
a) providing a first stream comprising methane;
b) providing a second stream which is a bromine-rich stream;
c) putting into contact said first stream with said second stream under bromination reaction conditions to obtain a third stream comprising at least unreacted methane, methyl bromide, dibromomethane, and hydrogen bromide;
d) removing said dibromomethane from said third stream under separation conditions, to produce a dibromomethane stream and a fourth stream comprising unreacted methane, methyl bromide and hydrogen bromide;
e) converting the fourth stream into chemicals;
f) separating hydrogen bromide from said third stream and/or said fourth stream, to provide a hydrogen bromide-rich stream; wherein the step of separating hydrogen bromide is performed by non-aqueous extraction;
g) subjecting the hydrogen bromide-rich stream of step (f) to an electrolysis step (g) to produce a hydrogen stream and/or a bromine stream, said bromine stream being optionally reused in step (c).

2. The process according to claim 1 , characterized in that the separation conditions of step (d) comprise temperature conditions of at most 150° C. and/or pressure conditions ranging between 0.1 MPa and 1.0 MPa.

3. The process according to claim 1 , characterized in that said electrolysis step (g) is carried out under gaseous phase or liquid phase.

4. The process according to claim 1 , characterized in that said electrolysis is performed under water-free conditions.

5. The process according to claim 1 , characterized in that the dibromomethane stream of step (d) is further converted into carbon by performing carbonization of said dibromomethane stream, said carbonization is carried out:
using electrical energy input; and/or
at a temperature ranging between 600° C. and 3000° C.

6. The process according to claim 1 , characterized in step (e) of conversion of the fourth stream into chemicals comprises the following sub-steps:
i. providing a first catalytical composition comprising at least one homologation catalyst,
ii. putting into contact said fourth stream with the first catalytical composition under first reaction conditions to provide a first product stream comprising C1-C7 hydrocarbons and hydrogen bromide;
iii. optionally, providing a second catalytical composition comprising at least one cracking catalyst and putting into contact said first product stream with the second catalytical composition under second reaction conditions, to provide a second product stream comprising C1-C8 hydrocarbons and HBr;
iv. separating C2-C4 hydrocarbons from said first product stream and/or from said second product stream when sub-step (iii) is carried out, to form a C2-C4 stream.

7. The process according to claim 6 , characterized in that said C2-C4 stream is further separated into an ethylene stream and/or into a propylene stream.

8. The process according to claim 6 , characterized in that the first catalytical composition is steamed before sub-step (ii) and the one or more homologation catalysts of the first catalytical composition comprise one or more zeolites and a binder, wherein said one or more zeolites comprise at least one 10-membered ring channel.

9. The process according to claim 6 , characterized in that the first reaction conditions comprise one or more of a temperature ranging between 250° C. and 460° C., a pressure ranging between 0.5 MPa and 1.0 MPa, and a weight hourly space velocity comprised between 0.1 h −1 and 100 h −1 .

10. The process according to claim 6 , wherein sub-step (iii) is carried out, said process being characterized in that said at least one cracking catalyst comprises one or more zeolites and/or one or more clays.

11. The process according to claim 10 , characterized in that said at least one cracking catalyst comprises one or more zeolites selected from silicalites from the MFI family, crystalline silicate from the MFI family with a Si/Al atomic ratio of at least 180, crystalline silicate from the MEL family with a Si/Al atomic ratio ranging between 150 and 800, and/or phosphorous-modified zeolite from the MFI, MEL, FER, or MOR family.

12. The process according to claim 6 , wherein sub-step (iii) is carried out, characterized in that the second reaction conditions comprise one or more of a reaction temperature ranging from 400° C. to 600° C., a pressure ranging between 0.4 MPa and 1.0 MPa, and a weight hourly space velocity comprised between 0.1 h −1 and 100 h −1 .

13. The process according to claim 6 , characterized in that the step (e) of conversion of the fourth stream into chemicals further comprises the sub-step (v) of separating an unreacted methane stream from said first product stream and/or from said second product stream when sub-step (iii) is carried out, to form a methane stream.

14. The process according to claim 13 , characterized in that said methane stream is recycled in the first stream of step (a).

15. The process according to claim 13 , characterized in that said methane stream is purged to form a fuel gas stream.

16. The process according to claim 1 , characterized in that the bromination reaction conditions of step (c) include one or more of a temperature ranging from 300° C. to 500° C. in the absence of a catalyst, a pressure ranging from 0.1 MPa to 2.0 MPa, and a molar ratio methane to bromine of at least 2.5:1.

17. The process according to claim 1 , characterized in that the step (a) of providing a first stream comprising methane comprises providing a natural gas comprising methane at a content of at least 75 mol. % of the total molar content of said natural gas.

18. The process according to claim 1 , characterized in that the step (a) of providing a first stream comprising methane comprises providing a natural gas and purifying the natural gas to remove one or more selected from sulphur, nitrogen, water, oxygen and carbon dioxide.

Assignees

• Totalenergies Onetech
• Sulzer Management Ag

Inventors

• Coupan Romuald
• Nesterenko Nikolai
• Veryasov Gleb

Classifications

• C07C17/10 Primary

  of hydrogen atoms (combined with addition of halogens to unsaturated hydrocarbons C07C17/06) · CPC title

• C01B7/093

  Hydrogen bromide · CPC title

• C01B32/05 Primary

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title

• C07C4/06

  Catalytic processes {(C07C4/025 takes precedence)} · CPC title

• C25B1/02

  Hydrogen or oxygen · CPC title