Reactors and systems for oxidative coupling of methane
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 (C 2+ 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 C 2+ compounds.
1. A method for producing hydrocarbon compounds including two or more carbon atoms (C 2+ compounds), the method comprising:
(a) performing an oxidative coupling of methane (OCM) reaction in an OCM reactor to produce an OCM effluent comprising carbon dioxide (CO 2 ), hydrogen (H 2 ), one or more C 2+ compounds, and methane (CH 4 );
(b) separating the OCM effluent into (i) a first stream comprising at least some of the one or more C 2+ compounds and (ii) a second stream comprising carbon monoxide (CO), CO 2 , H 2 , and CH 4 ;
(c) methanating the second stream to produce a first OCM reactor feed comprising CH 4 formed from the H 2 and CO and/or CO 2 in the second stream;
(d) methanating a third stream comprising CH 4 and H 2 to produce a second OCM reactor feed comprising CH 4 , which third stream is from an ethylene cracker; and
(e) directing the first and second OCM reactor feeds to the OCM reactor.
2. The method of claim 1 , wherein the second stream and the third stream are methanated in a single methanation reactor.
3. The method of claim 1 , further comprising providing at least a portion of the first stream to the ethylene cracker.
4. The method of claim 3 , wherein the at least the portion of the first stream is provided to a gas compressor or a fractionation unit of the ethylene cracker.
5. The method of claim 1 , wherein the third stream is the overhead stream of a demethanizer unit of the ethylene cracker.
6. The method of claim 1 , wherein the separating in (b) is performed at least in part in a pressure swing adsorption (PSA) unit.
7. The method of claim 1 , wherein the separating in (b) is performed at least in part with a CO 2 removal system or a process gas dryer.
8. The method of claim 1 , wherein the OCM effluent is compressed prior to (b).
9. The method of claim 1 , further comprising feeding oxygen (O 2 ) as an oxidizing agent to the OCM reactor, which O 2 takes part in the OCM reaction.
10. The method of claim 1 , wherein the OCM effluent comprises carbon monoxide (CO) that is converted into CH 4 in (c).
11. The method of claim 1 , wherein the OCM reaction further reacts CH 4 from natural gas to achieve additional ethylene production.
12. An oxidative coupling of methane (OCM) system for production of hydrocarbon compounds including two or more carbon atoms (C 2+ compounds), comprising:
(a) an OCM subsystem that (i) takes as input a feed stream comprising methane (CH 4 ) and an oxidizing agent, and (ii) generates a product stream comprising C 2+ compounds from the CH 4 and the oxidizing agent;
(b) a separation subsystem fluidically coupled to the OCM subsystem that separates the product stream into (i) a first stream comprising C 2+ compounds and (ii) a second stream comprising hydrogen (H 2 ) and carbon dioxide (CO 2 ) and/or carbon monoxide (CO);
(c) a methanation subsystem fluidically coupled to the second stream and to the OCM subsystem, wherein the methanation subsystem converts H 2 and CO 2 and/or CO into CH 4 ; and
(d) an ethylene cracker subsystem fluidically coupled to the methanation subsystem that provides CH 4 , H 2 , CO 2 , and/or CO to the methanation subsystem.
13. The system of claim 12 , wherein the methanation subsystem provides CH 4 to the OCM subsystem.
14. The system of claim 12 , wherein the ethylene cracker subsystem comprises a demathanizer that provides CH 4 , H 2 , CO 2 , and/or CO to the methanation subsystem.
15. The system of claim 12 , wherein the first stream is fluidically coupled to the ethylene cracker subsystem, and the ethylene cracker subsystem is configured to fractionate the first stream.
16. The system of claim 12 , wherein the separation subsystem comprises a pressure swing adsorption (PSA) unit.
17. The system of claim 12 , wherein the OCM subsystem reacts CH 4 from natural gas with the oxidizing agent in an OCM reaction.
18. The system of claim 12 , wherein the oxidizing agent comprises O 2 .
19. The system of claim 18 , wherein the O 2 is generated from air.
20. The system of claim 12 , wherein the OCM subsystem comprises at least one OCM reactor.
21. The system of claim 20 , wherein the OCM subsystem comprises at least one post-bed cracking unit within the at least one OCM reactor or downstream of the at least one OCM reactor, which post-bed cracking unit is configured to convert at least a portion of alkanes in the product stream to alkenes.