Efficient oxidative coupling of methane processes and systems

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

• an OCM unit comprising a single OCM reactor having two reaction zones within the single OCM reactor, the reaction zones comprising:
• (i) a methane conversion zone comprising a fixed OCM catalyst bed configured to receive methane (CH4) and an oxidizing agent in an OCM process over the fixed OCM catalyst bed to yield an OCM product stream comprising compounds with two or more carbon atoms;
• and
• (ii) an ethane conversion zone comprising a post-bed cracking (PBC) unit disposed immediately downstream and physically separated from the fixed OCM catalyst bed, the PBC unit configured to receive the OCM product stream and react alkanes from the OCM product stream to yield an OCM effluent stream comprising one or more alkenes, including ethylene, and compounds with two or more carbon atoms;
• a methanation unit in fluid communication with the OCM unit and configured to receive CO and/or CO2 contained in the OCM effluent stream and to react at least portion of the CO and/or CO2 in a methanation process to form CH4 and to direct at least a portion of the formed CH4 to the OCM unit;
• a heat exchanger in fluid communication with the OCM unit and the methanation unit, wherein the heat exchanger is configured to transfer heat from the OCM effluent stream to an effluent stream comprising CH4 from the methanation unit;
• and
• a computer subsystem comprising one or more computer processors programmed to select a plurality of operating conditions sufficient to perform a process that comprises (i) use of the OCM unit to conduct the OCM process to yield the OCM product stream, (ii) use of the PBC unit to react the alkanes to yield the OCM effluent stream, and (iii) use of the methanation unit to react the CO and/or CO2 to form CH4, wherein the plurality of operating conditions is selected such that the system operates at a carbon efficiency of at least about 50%.

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

• an OCM unit comprising a single OCM reactor having two reaction zones within the single OCM reactor, the reaction zones comprising:
• (i) a methane conversion zone comprising a fixed OCM catalyst bed configured to receive methane (CH4) and an oxidizing agent in an OCM process over the fixed OCM catalyst bed to yield an OCM product stream comprising compounds with two or more carbon atoms;
• and
• (ii) an ethane conversion zone comprising a post-bed cracking (PBC) unit disposed immediately downstream and physically separated from the fixed OCM catalyst bed, the PBC unit configured to receive the OCM product stream and react alkanes from the OCM product stream to yield an OCM effluent stream comprising one or more alkenes, including ethylene, and compounds with two or more carbon atoms;
• a methanation unit in fluid communication with the OCM unit and configured to receive CO and/or CO2 contained in the OCM effluent stream and to react at least portion of the CO and/or CO2 in a methanation process to form CH4 and to direct at least a portion of the formed CH4 to the OCM unit;
• a heat exchanger in fluid communication with the OCM unit and the methanation unit, wherein the heat exchanger is configured to transfer heat from the OCM effluent stream to an effluent stream comprising CH4 from the methanation unit;
• and
• a computer subsystem comprising one or more computer processors programmed to select a plurality of operating conditions sufficient to perform a process that comprises (i) use of the OCM unit to conduct the OCM process to yield the OCM product stream, (ii) use of the PBC unit to react the alkanes to yield the OCM effluent stream, and (iii) use of the methanation unit to react the CO and/or CO2 to form CH4, wherein the plurality of operating conditions is selected such that the system consumes less than 120 MMBtu of energy per ton of ethylene (C2H4) or C3+ compounds enriched.