Evaluation and modeling of part-load performance of coal-fired power plant with postcombustion CO₂ capture

The share of the fossil-fuel power systems in the European Union energy portfolio has recently increased, even with new environmental incentives aimed at the reduction of CO₂ emissions from the power sector. Implementation of carbon capture technologies has been identified as a critical step toward reduction of CO₂ emissions. As the power plants usually operate with changing loads to meet the electricity demand, it is important to evaluate the process performance under different operating loads. Therefore, this study provides a methodology for modeling of part-load operation of coal-fired power plants in a process simulator, such as Aspen Plus. The part-load power plant model is validated using data from the literature, and it was demonstrated that a maximum discrepancy of 5% was obtained for the live steam pressure prediction at 40% load, while the discrepancy for all other compared parameters at other loads did not exceed 3%. Furthermore, the part-load model is used to evaluate the performance of the retrofitted power plant with the CO₂ capture plant at different loads, with monoethanolamine as a solvent, revealing that the net efficiency varied between 28.2%_HHV and 21.1%_HHV. Moreover, the analysis showed that neglecting the off-design conditions due to steam extraction would result in overestimating the net thermal efficiency by up to 1.3%_HHV points at 100% load operation and steam extracted at 11.9 bar.