具备FCB功能电站汽轮机旁路容量的计算分析

Calculation and Analysis of the Steam Turbine Bypass Capacity for Power Station Possessing FCB Function

介绍了外高桥2×900 MW超临界机组低旁容量偏小,FCB过程中工质循环不平衡的问题。为了实现FCB功能,同时兼顾考虑设备投资的影响,合理地选择汽轮机旁路容量,以实际工程为例,针对中压缸启动的汽轮机,对机组典型启动工况和FCB瞬态、稳态工况进行了分析,确定了各工况旁路计算的边界条件。通过对各种可能出现的工况进行旁路计算,认为FCB稳态运行工况旁路入口蒸汽压力低、温度高、比容大,决定了旁路容量的选择。根据计算分析,认为通过设置60%BMCR高压旁路、85%BMCR低压旁路及40%BMCR容量PCV阀,为机组能顺利投产并具备FCB功能奠定了基础。

This paper introduces the existing problems of LP bypass insufficient capacity of WGQ 2 × 900 MW supercritical units which cause unbalanced working medium during FCB. In order to implement FCB, designers should appropriately choose the steam turbine bypass capacity, meanwhile take into account the influence of equipment investment, Taking an actual project as the example, this paper analyzes the typical mode of starting for the units and FCB transient and steady conditions, determines the boundary conditions of bypass calculation under various working mode. The power station is equipped with FCB function and intermediate pressure cylinder start up mode. Through the calculation of steam turbine bypass under possible conditions, this paper thinks FCB steady operating conditions determine the selection of bypass capacity because of low steam pressure, high temperature and large volume. According to the calculation analysis, this paper thinks it lays the foundation for the unit smoothly putting into production and possessing FCB function by means of setting 60% BMCR HP bypass, 85% BMCR LP bypass and 40% BMCR superheater outlet PCV .