Thermodynamic analysis and operation strategy optimization of a coal-fired power plant incorporating the CO2 capture process

As the share of renewable energy sources in the grid continues to rise, the flexible, low-carbon and grid-friendly coal-fired power generation is becoming crucial for the counties rich in coal. However, the investigation related to the operational load range of coal-fired power plants equipped with the CO2 capture system is still limited. This study analyzed the effect of a full flue gas carbon capture system on the operational load range of a large-scale coal-fired power plant and conducted a sensitivity analysis of critical parameters (CO2 capture amount, CO2 capture ratio, regeneration energy consumption, and the capacities of power plants) on the peak shaving performance. A new operational strategy that combines low-pressure cylinder near-zero output technology (LP-ZO) and lean-rich solvent storage was proposed to enhance the plant's operational load range. Finally, an economic analysis considering electricity and carbon markets to assess the profitability of different operational strategies was performed. Results indicated that full flue gas carbon capture decreased the referenced power plant's operational load range by 46.1 % compared to the power plant without CO2 capture. Reducing the capture ratio, developing the new solvent with less regeneration energy and adopting the power plants with small capacity would help to alleviate the impact of the operational load range. Moreover, adopting the proposed operational strategy effectively increased the power plant's operational load range by 41.7 %, increased annual net profit by approximately $3.91 million, and resulted in a payback period of about 2.66 years.