An improved coal-fired power plant integrated with carbon capture process incorporating Carnot battery and solvent storage for waste heat upgrading and flexible operation

Carbon dioxide capture and peak-shaving are two major challenges for conventional coal-fired power plants (CFPPs). Integrating energy storage systems can significantly enhance the peak-shaving capacity of CFPPs and mitigate the operational penalties associated with the carbon capture process. This study proposes a novel peak-shaving scheme that couples a Carnot battery (CB) system and a solvent storage system into a coal-fired power plant equipped with post-combustion carbon capture (CFPP-PCC). A comprehensive thermoeconomic model is developed to evaluate the proposed system. Results indicate that, by recovering and upgrading waste heat from reboiler steam extraction, the CB achieves a high equivalent round-trip efficiency of 82.47%. With a fixed 90% CO2 capture rate, the adjustable load range expands from 301.7-563.5 MW to 96.8-623.4 MW, which is 2.01 times wider than that of a conventional CFPP-PCC system. Economic analysis shows that the net present value and the dynamic payback period are 226.17 M$ and 1.72 years, respectively. This study provides valuable insights for enhancing the operational flexibility of CFPP-PCC units.