Separation methods and systems for oxidative coupling of methane

Abstract

The present disclosure provides a method for generating higher hydrocarbon(s) from a stream comprising compounds with two or more carbon atoms (C 2+ ), comprising introducing methane and an oxidant (e.g., O 2 ) into an oxidative coupling of methane (OCM) reactor. The OCM reactor reacts the methane with the oxidant to generate a first product stream comprising the C 2+ compounds. The first product stream can then be directed to a separations unit that recovers at least a portion of the C 2+ compounds from the first product stream to yield a second product stream comprising the at least the portion of the C 2+ compounds.

1 . A method for generating compounds with two or more carbon atoms (C 2+  compounds), comprising:
 (a) directing oxygen (O 2 ) and methane (CH 4 ) into an oxidative coupling of methane (OCM) reactor that reacts said O 2  and CH 4  in an OCM process to yield a product stream comprising (i) C 2+  compounds including ethylene (C 2 H 4 ) and (ii) carbon dioxide (CO 2 ); and 
 (b) directing said product stream from said OCM reactor into a separations unit that employs a CO 2  separation unit to separate said CO 2  from said product stream and enrich said C 2+  compounds in said product stream, which CO 2  separation unit employs (i) sorbent or solvent separation of CO 2 , (ii) membrane separation of CO 2 , (iii) cryogenic or low temperature separation of CO 2  having an operating temperature greater than a boiling point of methane and less than a boiling point of CO 2 , (iv) metal-organic framework-based separation, or (v) antisublimation separation of CO 2 . 
 
     
     
         2 . (canceled) 
     
     
         3 . The method of  claim 1 , wherein said sorbent or solvent separation of CO 2  employs an amine based absorption unit. 
     
     
         4 .- 19 . (canceled) 
     
     
         20 . The method of  claim 1 , further comprising directing said CO 2  from said product stream to a methanation reactor that reacts said CO 2  to yield a methanation product stream comprising methane. 
     
     
         21 . (canceled) 
     
     
         22 . The method of  claim 1 , further comprising separating said product stream into (i) an ethylene product stream comprising ethylene and (ii) a C 3+  product stream comprising compounds with three or more carbon atoms (C 3+  compounds). 
     
     
         23 .- 56 . (canceled) 
     
     
         57 . A method for generating compounds with two or more carbon atoms (C 2+  compounds), comprising:
 (a) directing oxygen (O 2 ) and methane (CH 4 ) into an oxidative coupling of methane (OCM) reactor that reacts said O 2  and CH 4  in an OCM process to yield a product stream comprising (i) C 2+  compounds including ethylene (C 2 H 4 ) and (ii) C 1  compounds including un-reacted CH 4 ; and 
 (b) directing said product stream into a separations unit containing a metal organic framework (MOF) that produces (i) a bottoms stream comprising said C 2+  compounds and (ii) an overhead stream comprising said C 1  compounds. 
 
     
     
         58 . The method of  claim 57 , further comprising:
 (c) directing said overhead stream to a methanation unit for converting carbon dioxide (CO 2 ) and/or carbon monoxide (CO) into methane (CH 4 ); and   (d) directing said CH 4  into said OCM reactor.   
     
     
         59 . The method of  claim 57 , further comprising:
 (e) directing said bottoms stream to a second separations unit containing a metal organic framework (MOF) that separates olefins from paraffins.   
     
     
         60 . The method of  claim 57 , wherein the separations unit comprises a pressure swing absorber (PSA) that contains the MOF. 
     
     
         61 . The method of  claim 57 , wherein the separations unit comprises a temperature swing absorber (TSA) that contains the MOF. 
     
     
         62 . The method of  claim 57 , wherein the C 1  compounds include hydrogen (H 2 ). 
     
     
         63 . A method for generating compounds with two or more carbon atoms (C 2+  compounds), comprising:
 (a) directing oxygen (O 2 ) and methane (CH 4 ) into an oxidative coupling of methane (OCM) reactor having a catalytic section and a cracking section to produce an OCM product stream, which catalytic section reacts said O 2  and CH 4  to yield ethylene (C 2 H 4 ), ethane (C 2 H 6 ) and heat, which cracking section uses said heat to convert C 2 H 6  into C 2 H 4 , and which product stream comprises (i) C 2+  compounds including ethylene (C 2 H 4 ) and ethane (C 2 H 6 ) and (ii) C 1  compounds including un-reacted CH 4 ; 
 (b) directing said product stream into a separations unit containing a metal organic framework (MOF) that produces (i) a first stream comprising said C 2 H 4 , (ii) a second stream comprising said C 2 H 6  and (iii) a third stream comprising said C 1  compounds; 
 (c) directing said second stream into said cracking section; and 
 (d) directing said third stream into said catalytic section. 
 
     
     
         64 . The method of  claim 63 , wherein said third stream is directed to a methanation unit prior to directing to said catalytic section, which methanation unit converts carbon dioxide (CO 2 ) and/or carbon monoxide (CO) into methane (CH 4 ). 
     
     
         65 . The method of  claim 63 , wherein the separations unit comprises a pressure swing absorber (PSA) that contains the MOF. 
     
     
         66 . The method of  claim 63 , wherein the separations unit comprises a temperature swing absorber (TSA) that contains the MOF. 
     
     
         67 . The method of  claim 63 , wherein the C 1  compounds include hydrogen (H 2 ). 
     
     
         68 .- 129 . (canceled) 
     
     
         130 . A system for generating compounds with two or more carbon atoms (C 2+  compounds), comprising:
 an oxidative coupling of methane (OCM) reactor configured to receive oxygen (O 2 ) and methane (CH 4 ) and react said O 2  and CH 4  to produce an OCM product stream, said OCM reactor having a catalytic section and a cracking section, which catalytic section reacts said O 2  and CH 4  to yield ethylene (C 2 H 4 ), ethane (C 2 H 6 ) and heat, which cracking section uses said heat to convert C 2 H 6  into C 2 H 4 , and which product stream comprises (i) C 2+  compounds including ethylene (C 2 H 4 ) and ethane (C 2 H 6 ) and (ii) C 1  compounds including un-reacted CH 4 ; and 
 a separations unit fluidically coupled to said OCM reactor and configured to receive said product stream from said OCM reactor, wherein said separations unit contains a metal organic framework (MOF) that produces (i) a first stream comprising said C 2 H 4 , (ii) a second stream comprising said C 2 H 6  and (iii) a third stream comprising said C 1  compounds, and wherein said second stream and said third stream are directed into said cracking section and said catalytic section respectively. 
 
     
     
         131 . The system of  claim 130 , wherein said third stream is directed to a methanation unit prior to directing to said catalytic section, which methanation unit converts carbon dioxide (CO 2 ) and/or carbon monoxide (CO) into methane (CH 4 ). 
     
     
         132 . The system of  claim 130 , wherein the separations unit comprises a pressure swing absorber (PSA) that contains the MOF. 
     
     
         133 . The system of  claim 130 , wherein the separations unit comprises a temperature swing absorber (TSA) that contains the MOF. 
     
     
         134 . The system of  claim 130 , wherein the C 1  compounds include hydrogen (H 2 ).