300MW机组锅炉中速磨煤机改造后出力不足问题的解决

Solution on insufficient output after retrofit of medium speed pulverizer in 300 MW unit

针对张家口发电厂8号锅炉4号磨煤机静风环改为活动风环后出现出力不足、电耗明显偏高,对应燃烧器结渣较为严重的问题,经分析认为磨煤机出力不足的主要原因是磨煤机分离器挡板关得过小,回粉量太大,磨煤机循环碾磨所致;燃烧器附近结渣主要由于该磨煤机4根粉管的一次风速偏差太大,造成火焰扫墙贴壁,炉内气流组织不佳所致。通过全面的优化调整试验,解决了磨煤机出力不足问题,锅炉结渣现象明显减轻,电耗也恢复到原水平。

After throat ring was replaced by rotating throat ring at the No.4 mill of No.8 coal-fired boiler in Zhangjiakou power plant, mill output became insufficient, electricity consumption became obviously high and serious slagging problem came on corresponding burners. Analysis showed that insufficient mill output was caused by too fine pulverized coal, which was due to too small separator baffle opening, making much part of pulverized coal sent back to mill. While slagging around the burner area was due to high primary air speed deviation among the four coal pipes of the mill and terrible airflow state in boiler, which resulted in slag bonding around burners. By means of all-around adjustment and optimization tests, the problem of insufficient mill output was solved, slag bonding in boiler has been alleviated, and the pulverizer performance was brought back to the original level.