耦合熔盐储热的超临界二氧化碳循环系统变负荷发电效率提升方法

To address the significant reduction in power generation efficiency and operational economy of supercritical carbon dioxide (SCO₂) power cycle systems under off-design conditions, a method for enhancing the load-following power generation efficiency of SCO₂cycle systems is proposed. In the design scheme, multiple small-capacity units are employed instead of a single large-capacity unit. In the operational mode, a combination of series and parallel operation among multiple units is utilized. By establishing a real-time dynamic model of an SCO₂cycle system coupled with molten salt thermal energy storage, a comparison is made between the multi-unit scheme and the traditional single-unit scheme in terms of load-following efficiency, peak shaving range, and operational economy. The results indicate that for a single-unit system with a rated power of 300 MW, when the output power is reduced from the rated power to 20% of the rated power, the efficiency decreases from 55. 01 % to 21. 97%. The multi-unit system operating in a series-parallel combination mode can increase efficiency by an average of 7. 92% and expand the peak shaving range from 100% to 20% of the rated power to 100% to 3. 33 % of the rated power. Furthermore, when applied to peak shaving, the multi-unit system can save 12% of molten salt consumption compared to the traditional single-unit system. The proposed method for enhancing load-following efficiency of SCO₂cycle systems provides valuable insights for improving the generation efficiency and operational economy of power plants.