600 MW亚临界机组再热汽温低原因分析及对策

Study on the Causes and Countermeasures for Low Reheat Steam Temperature of 600 MW Sub-critical Unit

本文分析了某电厂600 MW亚临界机组实施综合提效改造效果,发现改造后锅炉再热蒸汽系统由537℃提温至573℃,在机组启动后低负荷运行阶段中,存在锅炉侧再热汽温长时间欠温且无法有效提升的情况。通过统计分析锅炉尾部烟道调节挡板开度、锅炉运行总风量、机组冷再抽汽供热量等实验数据,考察了对机组再热温度的影响范围,在调整多种运行方式的基础上,发现减小左右侧再热器出口汽温偏差,可以提高再热汽温平均温度,从而可以有效提高机组运行效率。

The comprehensive efficiency improvement transformation effect of a 600 MW sub-critical unit in a power plant is analyzed,and It is found that the temperature of boiler reheat steam system is increased from 537℃to 573℃after the improvement.In the low load operation stage after the start-up of the unit,the boiler reheat steam temperature is under-temperature for a long time and cannot be raised effectively.Through statistical analysis of the experimental data such as the flue regulating baffle opening of the boiler tail,the total air volume of the boiler operation,and the heat supply of the unit’s cold and re-extraction steam,the influence range on the reheat temperature was investigated.On the basis of adjusting various operation modes,it is found that reducing the steam temperature deviation at the the left and right side of the re-heater's outlet can increase the average temperature of the reheated steam temperature,thereby effectively enhancing the operating efficiency of the unit.