1000MW超超临界汽轮机蒸汽参数的优化及讨论

Discussion and Optimization of Steam Parameters of 1000MW Ultra-supercritical Steam Turbines

探讨了1000 MW超超临界汽轮机组的参数及运行方式。外高桥三期2×1000 MW汽轮机为上汽(SIEMENS)机型,采用补汽阀调频及过负荷调节。以压力条件作为划分定压和滑压的判据,最高冷却水温条件下,功率≤1000 MW时不开补汽阀;其它水温下能在功率>1000 MW且p<27MPa时尽可能进行滑压运行;它采用≥3D弯管等,降低造价,降低再热系统压降时,降低冷却水温度,单独设汽动给水泵汽轮机的凝汽器,降低进入主凝汽器的蒸汽流量及热负荷,以降低机组平均背压和端差等,机组运行性能因而提高。

Parameters and the operation mode of 1000MW ultra-supercritical steam turbines is being discussed. Two such units, manufactured by Shanghai Turbine Works according to Siemens＇technology, are to be installed in the course of Waigaoqiao Power Plant＇s third stage of construction. These units are provided with an overload valve for grid frequency adjustment and overload control purposes, according to steam pressure used as the dividing criterion. The unit operates either on constant or sliding pessure; the overload valve remains closed under highest cooling water temperature, as long as the power output does not exceed 1000MW; under other cooling water temperature conditions and for p 〈 27 MPa, the unit should ron whenever possible on gliding pressure. By using pipe-bends of ≥3D and after measures, the construction cost is being reduced, as well as the pressure drop of the reheating system; by lowering the cooling water＇ s design temperature, providing the feed water pump driving turbine with a separate condenser, and by reducing the exhaust steam flow into the main condenser and the latter＇ s heat load to diminish the unit＇ s back pressure and terminal temperature difference etc. ,the unit＇s operational properties are raised