Dynamic performance and load response rate control optimization of a thermal power plant coupled with adsorption-based compressed CO₂ energy storage system

To address the urgent need for enhanced flexibility in power systems due to the large-scale grid integration of renewable energy, this paper proposes coupling thermal power units with an adsorption-based compressed CO₂ energy storage (AB-CCES) system. By leveraging its “heat and electricity co-storage/co-utilization” characteristics, this approach improves the load regulation flexibility of thermal power units. In this paper, the nonlinear dynamic model is constructed based on measured data from a 300 MW thermal power unit. By integrating the dynamic models of various components within AB-CCES system, a comparative analysis is conducted on the thermodynamic and dynamic performance under four operating modes, including constant pressure and sliding pressure. The results indicate that under the SP-SP mode, throttling and flow-matching losses are reduced most effectively, yielding the round-trip efficiency and energy storage density of 75.77%, 3.93 kWh/m3. Compared to thermal power units, thermal efficiency of the integrated system increases to 41.30%, and heat consumption rate decreases to 8020.08 kJ/kWh. Based on this, the study proposes a coordinated control architecture for the integrated system and introduces an adaptive fuzzy PI controller for optimization within the AB-CCES loop. Simulation results show that adaptive fuzzy control significantly enhances the load response rate of the integrated system compared to a standalone thermal power unit: load-down rate reaches 7.84% Pe (vs. 1.29% Pe for the thermal unit), and load-up rate reaches 4.15% Pe (vs. 1.36% Pe for the thermal unit). Simultaneously, the control quality of main steam pressure and intermediate point specific enthalpy was effectively improved.