燃汽-蒸汽联合循环灵活性分析

Flexibility analysis of combined cycle of combustion-steam

新能源的快速发展冲击了电网的稳定性,也对火力发电机组的调峰调频能力提出了更高的要求。考虑到燃气-蒸汽联合循环机组具有热效率高、启停快、易于调峰等特性,使用燃气-蒸汽联合循环进行调峰调频是理想的选择。介绍燃气-蒸汽联合循环的工作方式和结构特性,比较不同的联合循环的优缺点,讨论联合循环机组在变工况运行时影响其效率的因素,并对某燃气热力电厂的不同运行工况进行了热力性质计算,对循环机组的变工况特性进行直观分析。分析得出,低负荷运行工况下,燃气-蒸汽联合循环的热效率随着负荷下降而呈现加快升高趋势,经济性很低,不宜长期运行。

The rapid development of new energy has impacted the stability of power grid and put forward higher requirements for the peak-frequency regulation ability of thermal power generation units. Considering the characteristics of gas-steam combined cycle unit, such as high thermal efficiency, quick start and stop, easy peak regula-tion, etc., it is a good choice to use gas-steam combined cycle for peak regulation and frequency regulation.Gas-steam combined cycle are introduced in this way of working and structure characteristics. Comparing the advantages and disadvantages of different combined cycle, combined cycle unit are discussed when operating variable condition, the factors which influence the efficiency of the different operating conditions of a gas of thermal power plant thermodynamic properties calculation, intuitive analysis of the characteristics of variable condition of cycle unit. It is concluded that under low load operation condition, the heat efficiency of gas-steam combined cycle increases rapidly with the decrease of load, and the economy is very low, so it is not suitable for long-term operation.