Patent ID: 8448418

Claim:
A method of controlling an exhaust stream, wherein the exhaust stream is generated by a turbomachine, the method comprising: operating a gas turbine that comprises an inlet system; wherein the gas turbine operatively generates the exhaust stream; operating a heat recovery steam generator (HRSG) installed downstream of the gas turbine, wherein the exhaust stream flows from the gas turbine to an inlet portion of the HRSG; operating at least one exhaust gas recirculation (EGR) system comprising: at least one EGR flow conditioning device and at least one flow control device; wherein the EGR system reduces the concentration of at least one constituent within the exhaust stream; and operating an EGR control system for controlling a composition of the exhaust stream flowing through the EGR system, wherein steps performed by the EGR control system comprise: receiving an EGR control reference; and determining a target EGR rate, wherein the target EGR rate of the exhaust stream controls at least one component of the EGR system and configured to operatively receive information for at least one of: an EGR mass fraction; and a concentration of the at least one constituent; wherein the EGR control system operatively determines a composition of the exhaust stream.