增设烟气-水换热器提升火电机组灵活性研究

Research on Increasing Flexibility of Thermal Power Units by Flue Gas⁃water Heat Exchanger

山东电网电源结构中可再生能源占比日益增多,火电机组不可避免地面临深度调峰、频繁调峰,热电机组冬季供暖时热电矛盾问题突出,对电网安全稳定和可再生能源消纳带来负面影响。传统热电解耦技术存在负荷调整区间窄、能源整体利用效率不佳等情况,提出一种增设烟气-水换热器方案,与传统中压缸抽汽技术互补供暖,可提升整体负荷调度范围,同时提升整体能源利用效率。经测算,烟气供热模式在小供热需求下最低电功率显著低于传统供热模式,相同供热需求下混合供热模式最大电功率、最小电功率均优于传统供热模式,且混合供热模式下最大供热量显著增多,可提升机组运行灵活性,增强机组热电解耦能力。

The proportion of renewable energy in the power supply structure of Shandong power grid is increasing day by day.Thermal power units have to participate in deep⁃peak shaving and frequent⁃peak shaving inevitably.The problem of thermal power contradiction is prominent when facing high thermal power demand in winter,which has a negative impact on the security and stability of power grid and the renewable energy acceptance.Traditional thermo⁃electric decoupling technology has problems such as narrow load adjustment range and poor overall energy utilization efficiency.A scheme of adding flue gas⁃water heat exchanger is proposed to supplement the traditional medium pressure cylinder extraction technology for heating.According to the calculation,the minimum electric power of flue gas heating mode is significantly lower than that of traditional heating mode under small heat demand.The maximum and minimum electric power of hybrid heating mode are better than that of traditional heating mode under the same heat demand.The maximum heating capacity under the mixed heating mode is significantly increased,which can improve the operation flexibility of the unit and enhance the thermo⁃electric decoupling ability of the unit.