300MW锅炉再热汽温低的原因分析及改造

某电厂300 MW亚临界锅炉在汽轮机经过通流改造后,出现了低负荷时再热蒸汽温度偏低的现象,通过对再热蒸汽温度调整试验数据的分析,得到再热蒸汽入口温度与其设计值偏差较大是导致再热蒸汽温度偏低的主要原因。根据锅炉热平衡计算的结果,提出了再热器增容改造的3种方案,通过分析对比,选出了最优方案并进行改造。由锅炉改造后的性能试验看出改造效果良好,再热蒸汽温度有了明显的升高,达到了再热汽温541 ℃的要求。与此同时,电厂的经济效益也得到了显著提高。

Cause Analysis for Low Reheat Steam Temperature and Transformations of 300-MW Boilers

For the 300-MW subcritical boiler in a power plant, the steam temperature at the outlet of the reheater has always been lower than the designed value after the turbine through-flow transformation. Through the analysis on the data from the reheat steam temperature adjustment test, it is observed that the steam temperature at the inlet of the reheater is much lower than the designed value. Based on the thermal balance calculation, three schemes for increasing the capacity of the reheater are proposed. After comparison, the most reasonable one is selected and put into practice. The performance test after the transformation indicates that the reheat steam temperature at the outlet of the reheater is improved significantly, reaching the designed value of 541 ℃ with the economic efficiency of the plant also improved greatly.