Oxygen-enriched combustion for natural gas combined cycle operation

A method for operating a power generation process, comprising:

• separating air using a pressure swing adsorption process to form a nitrogen-containing stream comprising 95 vol % or more of N2 and an oxygen-containing stream comprising 25 vol % to 48 vol % of O2;
• combusting a fuel with O2 from at least a portion of the oxygen-containing stream in the presence of a recycle stream in a combustion chamber of a turbine to form a flue gas, the O2 from the at least a portion of the oxygen-containing stream comprising 16 vol % to 35 vol % of a combined volume of i) the fuel, ii) the at least a portion of the oxygen-containing stream, and iii) the recycle stream, the flue gas comprising 12 vol % or more of CO2;
• forming the recycle stream from one or more first portions of the flue gas;
• and
• performing post-combustion capture on at least a second portion of the flue gas to form a CO2-containing product stream and one or more CO2-depleted flue gas streams, the one or more CO2-depleted flue gas streams comprising 30 vol % or less of the CO2 from the at least a second portion of the flue gas,
• wherein the pressure swing adsorption process comprises:
• exposing air to a sorbent having kinetic selectivity for O2 relative to N2 in a sorbent environment at a pressure of 200 kPa-a to 800 kPa-a to form an adsorption effluent comprising the nitrogen-containing stream;
• exhausting a blowdown effluent from the sorbent environment;
• purging the sorbent environment with at least a portion of the blowdown effluent to form the oxygen-containing stream;
• and
• purging the sorbent environment with a portion of the adsorption effluent.