1000MW二次再热BEST机组给水泵布置优化研究

Optimization of Pump Formation of 1000 MW Secondary Reheat BEST Units

针对1000 MW二次再热背压抽汽汽轮机(BEST)机组回热系统存在高压加热器汽水两侧压差较大的问题,提出了6种给水泵布置方案。考虑到给水泵位置改变的可靠性问题,计算了6种方案的有效汽蚀余量,确保BEST机组给水泵能够长期安全运行。利用EBSILON仿真软件搭建模型,在100%THA、75%THA、50%THA、40%THA、30%THA工况下分别对模拟仿真运行,比较和分析了6种方案的热经济性。研究结果表明,给水泵最佳布置位置在1#高压加热器的出口。该方案在100%THA工况下发电热耗率比原系统降低了16.5 kJ/kWh。

Aiming at the regenerative system of the 1000 MW secondary reheat backpressure extraction steam turbine(BEST)unit,the pressure difference between the steam and water sides of the high-pressure heater is large,and six feedwater pump layout schemes are proposed.Taking into account the reliability of the feedwater pump position change,the effective NPSH of the six schemes is calculated and compared to ensure the long-term safe operation of the BEST unit feedwater pump.Using EBSILON simulation software to build a model,the simulation operation is conducted under 100%THA,75%THA,50%THA,40%THA,and 30%THA respectively,the thermal economics of the six schemes are compared and analyzed,and it is considered that the feed pump is the best.It is resulted that the best location is at the exit of No.1 high pressure heater.This scheme reduces the heat consumption rate of power generation by 16.5 kJ/kWh under 100%THA conditions.