Process for separating hydrocarbon compounds

Abstract

Disclosed herein are processes for producing and separating ethane and ethylene. In some embodiments, an oxidative coupling of methane (OCM) product gas comprising ethane and ethylene is introduced to a separation unit comprising two separators. Within the separation unit, the OCM product gas is separated to provide a C 2 -rich effluent, a methane-rich effluent, and a nitrogen-rich effluent. Advantageously, in some embodiments the separation is achieved with little or no external refrigeration requirement.

1 .- 55 . (canceled) 
     
     
         56 . A process for producing hydrocarbon compounds via oxidative coupling methane (OCM), comprising:
 (a) directing a feed stream comprising methane and oxygen into an OCM reactor to generate an OCM product gas comprising hydrocarbon compounds with two or more carbon atoms (C 2+  compounds);   (b) separating at least a portion of said OCM product gas into a first stream and a second stream;   (c) expanding at least a portion of said first stream substantially isentropically to produce an expanded first stream; and   (d) directing said at least a portion of said first stream expanded in (c) and said second stream into a separations unit to generate a C 2 -rich effluent comprising at least a portion of said C 2+  compounds and an effluent comprising methane.   
     
     
         57 . The process of  claim 56 , further comprising, between (a) and (b), condensing at least a portion of said C 2+  compounds in said OCM product gas by reducing a temperature of said OCM product gas using one or more heat exchangers. 
     
     
         58 . The process of  claim 57 , wherein (b) further comprises, directing said at least a portion of said OCM product gas into one or more liquid-gas separators to separate said at least a portion of said OCM product gas into said first stream and said second stream. 
     
     
         59 . The process of  claim 58 , wherein said first stream comprises at least a portion of said methane, and wherein said second stream comprises at least a portion of condensed C 2+  compounds. 
     
     
         60 . The process of  claim 58 , wherein (b) further comprises, expanding said at least a portion of said OCM product gas substantially adiabatically in said one or more liquid-gas separators. 
     
     
         61 . The process of  claim 56 , further comprising, between (a) and (b), directing said OCM product gas into a carbon dioxide removal treatment unit to reduce a carbon dioxide content of said OCM product gas. 
     
     
         62 . The method of  claim 61 , wherein said carbon dioxide content of said OCM product gas is reduced to about 20 ppm or less. 
     
     
         63 . The process of  claim 56 , further comprising, between (a) and (b), directing said OCM product gas into a treatment unit to reduce a water vapor content of said OCM product gas. 
     
     
         64 . The process of  claim 63 , wherein said treatment unit comprises a thermal swing adsorption (TSA) process. 
     
     
         65 . The process of  claim 63 , wherein said water vapor content of said OCM product gas is reduced to about 0.01 mole percent or less. 
     
     
         66 . The process of  claim 56 , further comprising, directing an additional portion of said first stream and at least a portion of said effluent into an additional separations unit to generate a methane-rich effluent. 
     
     
         67 . The process of  claim 66 , wherein said methane-rich effluent has a methane content of at least about 90 mole percent. 
     
     
         68 . The process of  claim 66 , further comprising, directing at least a portion of said methane-rich effluent into said OCM reactor. 
     
     
         69 . The process of  claim 66 , further comprising, adjusting a pressure of said methane-rich effluent to produce one or more methane-rich streams at different pressures. 
     
     
         70 . The process of  claim 69 , wherein said one or more methane-rich streams comprise at least (i) a first methane-rich stream at a first pressure between about 5 pounds per square inch gauge (psig) and 30 psig, and (ii) a second methane-rich stream at a second pressure between about 30 psig and about 100 psig. 
     
     
         71 . The process of  claim 66 , wherein said separations unit is operated at a first temperature and a first pressure, and wherein said additional separations unit is operated at a second temperature lower than said first temperature and a second pressure lower than said first pressure. 
     
     
         72 . The process of  claim 56 , further comprising, (e) directing at least a portion of said C 2 -rich effluent into an acetylene reactor that converts at least a portion of acetylene in said at least a portion of said C 2 -rich effluent to ethylene. 
     
     
         73 . The process of  claim 56 , further comprising, (e) separating at least a portion of said C 2 -rich effluent into an ethylene-rich effluent and an ethane-rich effluent. 
     
     
         74 . The Process of  claim 56 , wherein said C 2 -rich effluent has an ethylene content of at least about 60 mole percent. 
     
     
         75 . The Process of  claim 56 , wherein said C 2 -rich effluent has an ethane content of at least about 60 mole percent.