核-气联合循环发电系统性能仿真分析

Simulation Analysis of Performance of Nuclear-Gas Combined Cycle Power Generation Systems

针对压水堆核电机组循环热效率较低及电网对核电调峰能力的需求,基于Ebsilon软件,在大亚湾核电站二回路热力系统模型基础上,建立核-气联合循环发电热力系统。以燃气轮机循环效率、联合循环效率作为热经济性指标,评价联合循环系统的性能,并分析环境温度、压力及燃气轮机负荷变化对系统性能的影响。结果表明:核-气联合循环系统热效率相比原核电机组提高13.15%,汽轮机输出功率增加75.49%,工作环境得到明显改善;环境温度降低或压力升高会提高燃气轮机效率及联合循环功率;燃气轮机降负荷时,通过补燃天然气可维持核蒸汽发生器进口温度不变,汽轮机仍有较高的输出功率,负荷可调节范围为56.57%~100%。

For the low cycle thermal efficiency of Pressurized Water Reactor(PWR)nuclear power units and the growing demand on the nuclear power peaking capacity of the power grid,using Ebsilon software,based on the thermodynamic system model of the secondary loop of Daya Bay Nuclear Power Station,the nuclear-gas combined cycle power generation thermodynamic system is established.Taking the gas turbine cycle efficiency and the combined cycle efficiency as the index of the heat economy,the performance of the combined cycle system is evaluated.At the same time,the effect of ambient temperature,pressure and gas turbine load on the system performance is analyzed.The results show that,the thermal efficiency of the nuclear-gas combined cycle system increased by 13.15%compared with the original nuclear power unit,the output power of the steam turbine increased by 75.49%,and the working environment of the steam turbine is improved obviously;The fall of ambient temperature will increase the efficiency and the power of the gas turbine,and the drop in ambient pressure will decrease the efficiency of the gas turbine and the combined cycle efficiency.When reducing the load of the gas turbine,the inlet temperature of nuclear reactor remains unchanged by afterburning the natural gas,and the steam turbine can still have high output power.The adjustable range of the load is from 56.57%to 100%.