Performance analysis of 1000 MW ultra-supercritical double reheat unit with back-pressure extraction steam turbine

The ultra-supercritical double reheat thermal system, featuring the back-pressure extraction steam turbine (BEST) system, effectively addresses the challenge of excessive extraction steam superheat. This solution significantly enhances power generation efficiency, contributing to practical advancements in energy conservation, emission reduction, and sustainable development. Focused on a 1000 MW ultra-supercritical double reheat unit with the BEST reheating system, this study examined thermal system performance and equipment energy consumption. Computational analyses under variable conditions explored the impact of reheat steam temperature and main steam pressure on unit thermal economy. Results revealed that higher steam temperatures increased main steam turbine power output while reducing the BEST output. The feedwater pump motor exhibited the highest energy consumption, consistently exceeding 50%. Additionally, increasing reheat steam temperature initially improved thermal system efficiency, but diminishing returns were observed at higher temperatures. Furthermore, maintaining reheat steam temperature and increasing main steam pressure further enhanced the thermal economy of the ultra-supercritical double reheat unit.