Reactors and systems for oxidative coupling of methane

Patent metadata

Field	Value
Publication number	US-10377682-B2
Application number	US-201816021441-A
Country	US
Kind code	B2
Filing date	Jun 28, 2018
Priority date	Jan 9, 2014
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

In an aspect, the present disclosure provides a method for the oxidative coupling of methane to generate hydrocarbon compounds containing at least two carbon atoms (C2+ compounds). The method can include mixing a first gas stream comprising methane with a second gas stream comprising oxygen to form a third gas stream comprising methane and oxygen and performing an oxidative coupling of methane (OCM) reaction using the third gas stream to produce a product stream comprising one or more C2+ compounds.

First claim

What is claimed is:

1. A process for production of hydrocarbons, the process comprising the steps of:
converting at least a feed stream comprising methane (CH 4 ) and oxygen (O 2 ) feed into a conversion effluent by oxidative coupling of methane (OCM);
directing said conversion effluent to at least one product retrieval stage to produce one or more product streams and a remaining conversion effluent;
directing at least a portion of said remaining conversion effluent to a hydrogenation stage to produce a hydrogenation effluent, and directing said hydrogenation effluent to a methanation stage to produce a recycle stream; and
adding at least part of said recycle stream to said feed stream.

2. The method of claim 1 , wherein said hydrogenation stage and methanation stage are comprised in a recycle loop.

3. The process according to claim 2 , wherein said recycle loop further comprises a CO 2 addition stage.

4. The process according to claim 1 , wherein CO 2 is added upstream said methanation step at said CO 2 addition stage and/or directly into said methanation stage.

5. The process according to claim 1 , wherein H 2 O is at least partially removed upstream and/or downstream one or more of said product retrieval steps.

6. The process according to claim 2 , wherein said recycle loop comprises a pre-methanation step.

7. The process according to claim 6 , wherein CO, CO 2 is pre-methanated and/or higher alkanes are reformed in said pre-methanation step.

8. The process according to claim 6 , wherein said pre-methanation step is carried out at T<400° C. or >400° C.

9. The process according to claim 6 , wherein at least part of effluent from said pre-methanation is recycled to upstream said pre-methanation step.

10. The process according to claim 1 , wherein said one or more product streams obtained at said one or more product retrieval stages comprise ethylene, CO 2 , aromatics and/or raw gasoline.

11. The process according to claim 1 , wherein said recycle stream comprises 90-99% CH 4 .

12. The process according to claim 1 , wherein said recycle stream comprises H 2 and/or CO at a concentration below 5%, below 1%, below 0.5%, such as below 10 ppm when added to said feed stream.

13. The process according to claim 1 , wherein said one or more product streams is obtained by separation from said conversion effluent through pressure swing adsorption, condensation, N 2 wash and/or distillation or other separation technologies.

14. The process according to claim 6 , wherein said pre-methanation step is carried out over a nickel-based catalyst at a pressure between 0.1 and 80 bars.

15. The process according to claim 1 , wherein said methanation stage is carried out over a nickel-based catalyst at a pressure between 0.1 and 80 bars.

16. The process according to claim 1 , wherein said methanation stage is carried out at T<400° C. or T>400° C., depending on if said unsaturated hydrogenation is desired or not.

17. The process according to claim 6 , wherein said hydrogenation, pre-methanation and/or methanation is carried out in a boiling water reactor preferably in a single boiling water reactor.

18. A method for producing hydrocarbon compounds, comprising:
(a) directing a feed stream comprising methane (CH 4 ) and an oxidizing agent into an oxidative coupling of methane (OCM) unit to generate from at least a portion of said CH 4 and said oxidizing agent an OCM effluent comprising said hydrocarbon compounds;
(b) recovering a portion of said OCM effluent in one or more product streams;
(c) directing an additional portion of said OCM effluent into a recycle loop that comprises (i) a hydrogenation unit that hydrogenates at least a portion of unsaturated hydrocarbons from said additional portion of said OCM effluent, and (ii) a methanation unit that reacts hydrogen (H 2 ) with carbon monoxide (CO) or carbon dioxide (CO 2 ) from said additional portion of said OCM effluent in a methanation reaction to form CH 4 , wherein said recycle loop outputs a recycle stream comprising said CH 4 generated by said methanation unit; and
(d) directing at least a portion of said recycle stream into said OCM unit.

19. The method of claim 18 , wherein said one or more product streams comprise ethylene (C 2 H 4 ), CO 2 , and/or hydrocarbon compounds having three or more carbon atoms (C 3+ compounds).

20. The method of claim 18 , further comprising directing a CO 2 stream into said methanation unit.

21. The method of claim 18 , further comprising removing water from said OCM effluent.

22. The method of claim 18 , further comprising reducing a concentration of hydrocarbon compounds having carbon-carbon double bonds or triple bonds in said OCM effluent prior to said methanation reaction.

23. The method of claim 18 , wherein said recycle stream comprises at least about 90% CH 4 .

24. The method of claim 18 , wherein said one or more product streams are recovered using pressure swing adsorption (PSA), condensation, and/or membrane separation.

25. The method of claim 18 , further comprising removing water from said recycle stream prior to (d).

26. The method of claim 25 , wherein at least about 70% of said water is removed from said recycle stream.

27. The method of claim 18 , wherein said additional portion of said OCM effluent is a part of said portion of said OCM effluent.

28. The method of claim 18 , wherein said methanation unit comprises a catalyst comprising one or more of ruthenium, cobalt, nickel and iron.

29. The method of claim 18 , wherein said methanation unit operates at a pressure between about 2 bar (absolute) and 60 bar, and a temperature between about 150° C. and about 400° C.

30. The method of claim 18 , wherein said carbon efficiency is at least about 50%.

Assignees

• Siluria Technologies Inc

Inventors

• Rafique Humera A
• Vuddagiri Srinivas
• Radaelli Guido
• Mccormick Jarod
• Duggal Suchia
• Cizeron Joel

Classifications

• F25J2270/06

  with multiple gas expansion loops · CPC title

• F25J2240/02

  Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream · CPC title

• F25J2230/08

  Cold compressor, i.e. suction of the gas at cryogenic temperature and generally without afterstage-cooler · CPC title

• F25J2270/04

  Internal refrigeration with work-producing gas expansion loop · CPC title

• F25J2200/76

  Refluxing the column with condensed overhead gas being cycled in a quasi-closed loop refrigeration cycle · CPC title