为了进一步降低燃煤发电机组在最低锅炉稳燃负荷下的电负荷率,采用Ebsilon软件建立了集成烟气及主蒸汽多热源熔盐储热的燃煤发电系统模型,并结合660MW超临界机组的案例对集成系统的热力学性能进行分析。计算结果表明：在储热过程中,主蒸汽最大分流流量为88.40 kg/s,燃煤机组的最低电负荷率可由30%降低至11.75%；而在释热过程中,燃煤发电系统的输出功率增加了88.50 MW,占额定负荷的13.40%；在30%THA储热并在75%THA释热时,集成系统的最高等效循环效率为85.89%。此外,还分析了集成系统在不同释热基准工况下的系统性能：在储热过程的附加?损为负,而在放热过程附加?损为正；集成系统在100% THA工况下放热的附加?损最大,最大附加?损为41.96 MW,而集成系统在50% THA工况下放热的附加?损最小,其最大附加?损为12.40 MW。总体而言,集成系统在30% THA储热并且在50% THA工况下释热时系统性能最好,系统等效循环效率最高可达94.35%。

To further reduce the electricity load rate of coal-fired power plants (CFPPs) under the minimum stable combustion load of the boiler, the molten salt heat storage system with multi-heat sources of flue gas and live steam was integrated into a CFPP. The simulation models were developed by Ebsilon software. The thermodynamic performance of the integrated system was analyzed through a case of a 660MW supercritical CFPP. Results show that during the charging process, the minimum electrical load rate of CFPP can be reduced from 30% to 11.75% due to the maximum split mass flow rate of the live steam at 88.40 kg/s. During the discharging process, the output power of CFPP increased by 88.50 MW, accounting for 13.40% of the rated load. The maximum equivalent round trip efficiency of the integrated system at the condition of 30%THA for charging and 75%THA for discharging is up to 85.89%. In addition, the system performance of the integrated system under different discharging conditions was analyzed. The additional exergy loss was negative during the charging process while was positive during the discharging process. The integrated system has the largest additional exergy loss at 41.96 MW under 100% THA for discharging and the lowest exergy loss at 12.40 MW under 50% THA for discharging. Overall, the integrated system shows great performance under the condition of 30%THA for charging and 50%THA for discharging with the maximum equivalent round trip efficiency at 94.35%.

TK219

国网陕西省电力有限公司科技项目(5226KY230004)