OPTIMIZATION OF ADVANCED STEAM CONDITION POWER-PLANTS

The modern pulverized-coal power plant is the product of continuous design experience and component improvement in the 20th century. In recent years, studies of the effect of high temperatures on turbine materials have led to major worldwide research and development programs on improving the thermal cycle by raising turbine-inlet pressure and temperature. This paper reviews the importance of various parameters in trying to optimize a turbine cycle designed for advanced steam conditions. Combinations of throttle pressure (between 3500 psi [24.1 MPa] and 10,000 psi [70 MPa]), throttle and reheat temperature (1000-degrees-F[538-degrees-C] to 1400-degrees-F [760-degrees-C]), and number of reheats are explored to establish a realistic turbine cycle design. Assessments and trade-offs are discussed, as applicable. Critical cycle components, feedwater cycle arrangements, and reheat pressure selections are analyzed in establishing an optimized steam turbine-boiler cycle for a 1000 MW turbine-generator. Applicability of results to smaller advanced steam turbines is given. A brief update on the high-temperature Wakamatsu turbine project in Japan is also given.