基于容积法的超临界二氧化碳循环发电系统负荷调控策略研究

Study on Load Control Strategy of a S-CO_(2) Cycle Power Generation System Based on Volumetric Method

以再压缩超临界二氧化碳(S-CO_(2))循环系统为研究对象,开展了基于容积法的系统降负荷调控策略研究,着重分析了系统对充放工质的动态响应并据此优化了调控策略。结果表明:采用常规容积法(直接排放工质)降负荷时,系统会因S-CO_(2)的真实气体效应产生运行不稳定性问题,通过先提升主压缩机入口温度再进行工质排放,则可避免这一问题,并可有效降低由于降负荷带来的系统循环热效率损失;最终的超临界升温-等温-降温容积法优化调控方案在50%负荷时循环热效率最高可达到额定工况的90%。

Taking a recompression supercritical carbon dioxide(S-CO_(2)) cycle system as the research object, the control strategy of the system in the load reduction process was studied by volumetric method. The dynamic response of the system to the charging and discharging working fluid was emphatically analyzed and the control strategy was optimized accordingly. Results show that the system will have operational instability problems due to the real gas effect of S-CO_(2)when conventional volumetric method is used to reduce the load(discharge working fluid directly). By increasing the inlet temperature of the main compressor and then discharging the working fluid, the problems can be avoided, and the cycle efficiency loss caused by load reduction can be effectively reduced. The maximum cycle efficiency of the optimized control strategy using supercritical volumetric method can reach 90% of the rated condition at 50% load.