由超临界CO2布雷顿循环和跨临界CO2循环组成的超临界CO2余热利用系统作为燃气轮机底循环,因其具有循环效率高、负荷调节速率快的特点,被认为是大规模消纳可再生能源的重要技术路线之一。为解决其在新能源大规模并网所造成的电网负荷波动情况下,系统快速变负荷中循环动态特性及负荷控制策略尚未明晰的问题,该文建立超临界CO2余热利用系统动态特性模型,获得燃气轮机排气温度和流量扰动下系统热力学参数响应特征,对比不同负荷跟随控制策略,确定超临界CO2余热利用系统变负荷过程中最优负荷控制策略。结果表明:在燃气轮机排气温度和流量扰动时,超临界CO2余热利用系统对于燃气轮机排气温度变化更为敏感,其超临界CO2余热利用系统总效率提升是燃气轮机排气流量扰动下的2.64倍。在超临界CO2余热利用系统总负荷由100%降至95%过程中,与超临界负荷跟随及按比例分配策略相比,采用超临界负荷跟随策略具有很好的负荷跟随能力并具有最高的超临界CO2余热利用系统总效率,为超临界CO2余热利用系统参与灵活调峰提供参考。

The supercritical CO2 waste heat utilisation system, which consists of supercritical CO2 Brayton cycle and transcritical CO2 cycle, as the bottom cycle of gas turbine, is regarded as one of the important technical routes for large-scale consumption of renewable energy due to its features of high cycle efficiency and fast load regulation rate. In order to solve the problem that the dynamic characteristics of the cycle and the load control strategy of the system in the rapid load change caused by the large-scale grid load fluctuation of new energy sources, the paper establishes a dynamic characteristic model of the supercritical CO2 waste heat utilisation system, obtains the response characteristics of the system"s thermodynamic parameters under the perturbation of the exhaust temperature and flow rate of the gas turbine, compares the different load-following control strategies, and determines the optimum load in the variable load process of the supercritical CO2 waste heat utilisation system. The optimal load control strategy is determined in the variable load process of the utilisation system. The results show that the supercritical CO2 waste heat utilisation system is more sensitive to the gas turbine exhaust temperature change under gas turbine exhaust temperature and flow rate perturbation, and the total efficiency of the supercritical CO2 waste heat utilisation system is 2.64 times higher than that under gas turbine exhaust flow rate perturbation. When the total load of the supercritical CO2 waste heat utilization system is reduced from 100% to 95%, compared with the supercritical load following and proportional allocation strategies, the supercritical load following strategy has a very good load following ability and the highest total efficiency of the supercritical CO2 waste heat utilization system, which provides a reference for the supercritical CO2 waste heat utilization system to participate in flexible peak shifting.

国家自然科学基金项目（面上项目，重点项目，重大项目）(52206006)；江苏省基础研究计划（自然科学基金）青年基金项目 (BK20210240)