600MW等级亚临界机组超超临界改造的热力系统设计分析

摘要

Taking a 660MW subcritical unit as a research model,build two thermal systems corresponding to two plans for parameter transformation of 600MW level units from subcritical to ultra supercritical.Calculation and analysis have been made according to two different ways to drive boiler feed pump,which are the conventional way or the spindle driving way. The influence on main steam flow and heat absorption,turbine exhaust flow and heat consumption rate has been quantitative analyzed.Results show that, with the transformation this article put forward, steam turbine heat consumption rate could decrease about 500kJ/(kW· h);gross plant efficiency increases nearly 4%,in spindle driving feed water pump plan,the heat consumption rate is about 20kJ/(kW· h)lower than conventional plan.Under partial load,conclusion looks almost the same as the rated load.%以某660MW亚临界机组为研究模型,构建了600MW等级亚临界机组超超临界改造的两种方案所对应的热力系统.根据锅炉给水泵驱动方式不同,提出了常规方式驱动给水泵与主轴驱动给水泵两种方案.定量分析了两种方案下主蒸汽流量、低压缸排汽流量和汽轮机组热耗率等参数的区别.结果表明:亚临界机组通过提出的方案进行超超临界改造,可以使汽轮机热耗率下降约500kJ/(kW· h),全厂毛效率提高近4%,主轴驱动给水泵的方案比常规方案热耗率降低约20kJ/(kW· h).部分负荷下,改造仍表现出良好的节能潜力,主轴驱动给水泵的改造方案热耗率仍低于常规方案.