Abstract: A gas turbine (10) includes a compressor (12) receiving inlet air (18) and producing compressed air, a combustor (14) receiving a combustion portion (30) of the compressed air and producing a hot combustion gas (32), and a turbine (16) receiving the hot combustion gas and producing an exhaust gas (28). The gas turbine also includes a bypass flow path (34) receiving a bypass portion (e.g. 36) of the compressed air and conducting the bypass portion into the exhaust gas to produce a cooled exhaust gas (44). In addition, the gas turbine includes a recirculation flow path (64) receiving a recirculation portion (e.g. 62) of the compressed air and conducting the recirculation portion into the inlet air upstream of the compressor to heat the inlet air.

Abstract: A catalytic gas turbine includes a compressor, a catalytic combustor, a turbine, and a flow path conducting a bypass portion of the compressed air around the combustor and turbine. A method of operating the catalytic gas turbine to activate a catalyst in the catalytic combustor includes opening an inlet guide vane upstream of the compressor to a position to produce an increased volume of compressed air. The increased volume exceeds a volume of compressed air needed to support combustion. A bypass portion of the compressed air is extracted and directed around the combustor and turbine. The method may also include extracting a recirculation portion of the compressed air and directing the recirculation portion into the inlet of the compressor.

Abstract: A gas turbine includes a compressor, a combustor, a turbine, and a flow path diverting an excess portion of the compressed air produced by the compressor around the turbine. The flow path conducts the excess portion into a turbine exhaust gas flow producing a cooled exhaust gas. A method of operating the gas turbine includes opening an inlet guide vane of the compressor to allow the compressor to produce an increased volume of compressed air. The increased volume exceeds a volume of compressed air needed to support combustion. An excess portion of the compressed air is directed into the exhaust gas to produce a cooled exhaust. In a combined cycle power plant, the cooled exhaust from the gas turbine may be used to warm a steam turbine portion to a desired temperature while allowing operation of the gas turbine at a power level that produces exhaust gas at a temperature higher than the desired temperature.