Enhancement of thermal power plant performance through solar-assisted feed water heaters: An innovative repowering approach

Abstract

Increasing the efficiency of a power plant by optimization or repowering has always been a crucial challenge for energy analysts. At the same time as natural energy resources are limited, the integration of renewable energy sources such as solar energy has been prioritized for the past few decades. This study presents a way of enhancing a thermal power plant with a regenerative reheating Rankine cycle, evaluating the impact of solar-powered heat exchangers on feed water heating at 200 MW single unit of the Shahid Montazeri Power Plant operating at 13 MPa and 540 °C. Increases in energy-exergy efficiencies, power output and fuel save due to this modification have been studied in 14 different cases which have been analyzed in Engineering Equation Solver (EES). The case studies cover replacing single, double, and triple Feed Water Heaters (FWH). Parametric analysis of the four most promising cases has been performed in varying operating conditions such as main steam and reheat steam temperature and pressure and condensation pressure. In the most favorable configuration (case 12), the net thermal power output increases to 225 MW while energy and exergy efficiency increases to 39.73 % and 43.99 % respectively. Exergy and energy loss across different major components have been presented as well which indicates room for further improvement and contributes valuable insights to thermal power plant optimization for sustainable and efficient energy solutions in the future.