Oxidative coupling of methane implementations for olefin production

A method for performing oxidative coupling of methane (OCM), comprising:

• (a) in a substantially adiabatic OCM reactor comprising a fixed catalyst bed, reacting oxygen (O2) with methane (CH4) in an OCM process to yield a product stream comprising (i) compounds with two or more carbon atoms (C2+compounds), including ethylene (C2H4), ethane (C2H6), and propylene (C3H6), (ii) hydrogen (H2), and (iii) carbon monoxide (CO) or carbon dioxide (CO2), wherein said OCM process liberates heat, and wherein an inlet temperature of said OCM reactor is at most about 600° C.;
• (b) directing said product stream from said OCM reactor and C2H6 from an ethane stream external to said OCM reactor into a cracking unit that cracks C2H6 using energy derived from said heat liberated in said OCM process, thereby increasing a concentration of C2H4 and H2 in said product stream;
• (c) directing said product stream from said cracking unit into a compressor that increases a pressure of said product stream using energy derived from said heat liberated in said OCM process;
• (d) directing said product stream from said compressor into a separations unit that enriches said C2H4 from said product stream using energy derived from said heat liberated in said OCM process;
• and
• (e) directing H2 and CO or CO2 from said product stream from said separations unit into a methanation reactor that reacts said H2 with said CO or CO2 from said product stream to form CH4.