压缩空气储能与燃气-蒸汽联合循环机组最佳耦合方案研究

Research on the Optimal Coupling Scheme of Compressed Air Energy Storage and Natural Gas Combined Cycle Units

为满足电网深度调峰要求,对燃气-蒸汽联合循环(NGCC)机组进行灵活性改造,将压缩空气储能(CAES)系统与NGCC机组耦合。利用Ebsilon软件进行模拟计算,寻找最佳耦合方案。计算分析了膨胀机入口空气参数变化对其输出功率的影响,并得到了CAES系统各部件的[火用]分布。结果表明,最佳耦合方案为——在储能阶段,抽取凝结水泵出口凝结水来吸收压缩热,再返回除氧器出口;在释能阶段,抽取少量中压缸抽汽加热膨胀机入口空气,再返回除氧器出口。通过提高膨胀机入口空气温度和流量,可使输出功率均线性增大;而且,提高流量对功率提升效果更为显著。对CAES系统进行[火用]分析时发现,换热器2、3和5的[火用]效率最低,节能潜力较大。

In order to meet the requirements of deep peak shaving of the power grid,the natural gas combined cycle(NGCC)units were flexibly modified,and the compressed air energy storage(CAES)system was coupled with the NGCC units.The Ebsilon software is used for simulation and calculation to find the best coupling scheme.The influence of the inlet air parameters of the expander on its output power is calculated and analyzed,and the exergy distribution of each component of the CAES system is obtained.The results show that the optimal coupling scheme is as follows:in the energy storage stage,the condensate water at the outlet of the condensate pump is pumped to absorb the compression heat,and then returns to the outlet of the deaerator;in the energy release stage,a small amount of steam is extracted from the intermediate pressure cylinder to heat the air at the expander inlet,and then return to the deaerator outlet.By increasing the inlet air temperature and flow rate of the expander,the output power uniformity can be increased.Moreover,increasing the flow has a more significant effect on the power increase.When analyzing the CAES system,it is found that the efficiency of heat exchangers 2,3 and 5 is the lowest and the energy saving potential is great.