1000MW二次再热机组抽汽参数确定与小汽机汽源研究

The Bleed Parameters Determination And Resource of Auxiliary Turbine Research of 1 000MW Double Steam Reheat Unit

以二次再热机组为模型,蒸汽焓为变量建立回热系统效率与蒸汽抽汽焓值的关系方程,以回热系统效率最大为目标函数推导出相邻两级加热器抽汽焓值的递推关系,确定1 000MW主蒸汽参数为35MPa/700℃/720℃/720℃二次再热机组再热前后各级最佳的抽汽焓值,结果表明:比采用给水等焓升方法确定机组效率高0.1%,加热器损总值减少1.37k J/kg。改变小汽机汽源抽汽口位置,进汽参数越高,机组效率越大。采用一次再热热段抽汽作为汽源时机组效率最大为55.52%,回热系统损最小为82.76k J/kg。

With secondary reheat unit, bleed enthalpy as variate for regenerative system analysis model, it develops the relationship equation between regenerative system efficiency and the bleed enthalpy, and derives the recursive relations between the adjacent bleed enthalpy for the maximal regenerative efficiency, then determines the optimal bleed enthalpy of the 1000MW unit whose main steam parameters is 35MPa/700℃/720℃/720℃. With the recursive equation, determines the rational bleed enthalpy of the double reheat unit,whose main steam parameters are 35MPa/700℃/720℃/720℃ ,The results show： the regenerative system efficiency is 0.1% higher than feed water equivalent heat rise method and the reheater exergy loss is 1.37kJ/kg lower. With the bleed location changes, the higher of the inlet steam parameters of the auxiliary turbine, the higher of the unit efficiency. When the steam source is the bleed steam after the first reheat, the unit efficiency is the highest which is 55.52% and the regenerative system exergy loss is the least which is 82.76kJ/kg.