Power plant and method of operation

A power plant comprises at least one main air compressor (12) and at least one gas turbine assembly. Each gas turbine assembly comprises a turbine combustor (32) for mixing a compressed ambient gas (26) with a recirculated low oxygen content gas flow (50) and a fuel stream (28) to form a combustible mixture for burning to form the recirculated low oxygen content gas flow (50). A turbine (34) is driven by the recirculated low oxygen content gas flow (50). A recirculation loop (52) allows for recirculation of the recirculated low oxygen content gas flow (50) from the turbine (34) to a turbine compressor (30). A gas flow extraction stream (31) extracts a portion of the recirculated low oxygen content gas flow (50) for delivery to a carbon monoxide catalyst unit (102). A portion of the compressed ambient gas (25) is directed to the carbon monoxide catalyst unit (102).