Patent ID: 9091182
Filing Date: 2015-07-28
Classification: F01K,F22D,F22G

Abstract:
1. A steam cycle system comprising: a boiler comprising a superheat section, a reheat section, and an economizer section, wherein the boiler is configured to receive a feedwater stream; a steam turbine system comprising a high pressure turbine and a lower pressure turbine, wherein the steam turbine system is configured to receive steam generated by the boiler; a condenser configured to receive at least a portion of the outlet steam from the steam turbine system; a high pressure feedwater heat exchanger configured to receive at least a portion of the feedwater stream, allow for an energy exchange between the portion of the feedwater stream and a steam stream, and output the portion of the feedwater stream to the boiler; a steam extraction line configured to provide a steam flow from an outlet of the high pressure turbine to the high pressure feedwater heat exchanger; a superheated steam temperature sensor; and a feedwater temperature control device comprising an isolation valve disposed in the steam extraction line, and a control valve disposed in a bypass line around the isolation valve, wherein the feedwater temperature control device is configured to control the temperature of the feedwater stream in response to the superheated steam temperature sensor sensing a decrease in the sensed superheated steam temperature below a superheated steam stream temperature set point by modulating the steam flow provided through the steam extraction line by passing the steam through the control valve and indirectly contacting the steam flow with the portion of the feedwater received by the high pressure feedwater heat exchanger when the isolation valve is in a closed position to reduce the steam production rate of the boiler per unit of fuel input, and sustain the reduced steam production rate of the boiler to raise the superheated steam temperature.