适应低负荷运行需求的600MW机组增效扩容改造技术分析与实践

Study and practise to adapt the part load property for 600 MW unit efficiency & capacity improvement modification

通过对汽轮机通流改造技术在低负荷运行工况的适应性研究,提出了依据试验结果比对来合理确定改造范围、考虑主辅机设备适配性合理设置增容目标、增加低负荷工况考核权重系数等应对策略以及汽轮机进汽方式调整、低压缸末级叶片优化选型等具体的改进措施。这些优化策略与措施在两台600 MW试点改造机组上得到了实际应用,显著提高了机组的低负荷运行性能,而对试点机组增效扩容收益的计算结果表明,机组年利用小时下降会对改造收益产生正比例的负面影响。

The steam turbine adaptability in the part load operation condition was studied and some assessment strategieswere proposed, for example the modification range should be determined in accordance to the results of performancetests, the capacity increasing goal should be considered with the main ＆ auxiliary equipment fitment, and the weightcoefficient should be set in the heat rate guarantee for part load conditions. These strategies and several improvementmeasures such as the steam inlet way adjustment and the last stage blade selection in low pressure cylinder have beenapplied on two 600 MW pilot retrofit steam turbine units, and improved the part load performance signally. But the cal-culation results also showed that the retrofit economic earnings would decrease in direct proportion with the runninghours fall down.