Performance Entitlement of Supercritical Steam Bottoming Cycle

Abstract

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 coalfired steam turbine power plants since the 1950s and can be considered a mature technology. Its application to the gasfired combined cycle systems presents unique design challenges due to the much lower gas temperatures (i.e., 650 آ°C at the gas turbine exhaust visأ vis 2000 آ°C in fossil fuelfired 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 secondlaw based exergy concept to rigorously quantify the performance entitlement of a supercritical highpressure 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.