Evaluating the Technical and Economic Feasibility of Adding a Power Recovery System to the Steam Condenser of a Lignite Coal-Fired Power Plant

Steam is the typical working fluid to drive turbo-generators in coal-fired power plants. It an effective fluid, but some of its energy extracted unusable form when condensed. A Power Recovery Cycle (PRC) using a more volatile Secondary Working Fluid (SWF) added steam cycle could improve efficiency. PRCs have been applied flue gas and for combined systems not traditional plant cycles. This paper details analysis adding PRC 500 MW lignite plant. validated model was developed three most attractive SWFs, benzene, methanol hydrazine, were then model. Adding methanol, or hydrazine will produce additional 59, 34, 49 MW, respectively. An AACE Class 4 factored broad capital cost estimate comparable operating costs revenue estimates evaluate feasibility. The processes had 2019 Net Present Values (NPVs) @12% -$32, -$59, +$35 million ± 40%, Thus, may be profitable at current modest increases U.S. Upper Midwest electricity prices around $0.0667/kWh.