Performance entitlement of supercritical steam bottoming cycle
27 December 2013
A supercritical steam bottoming cycle has been proposed as a performance enhancement option for gas turbine combined cycle power plants. The technology has been widely used in coal-fired steam turbine power plants since the 1950s and can be considered a mature technology.
Its application to the gas-fired combined cycle systems presents unique design challenges due to the much lower gas temperatures (i.e., 1,202°F [650°C] at the gas turbine exhaust vis-à-vis 3,632°F [2,000°C] in fossil fuel-fired steam boilers). Thus, the potential impact of the supercritical steam conditions is hampered to the point of economic infeasibility.
This technical brief draws upon the second-law based exergy concept to rigorously quantify the performance entitlement of a supercritical high-pressure boiler section in a heat recovery steam generator utilizing the exhaust of a gas turbine to generate steam for power generation in a steam turbine.