汽轮机积盐不开缸清洗的研究及应用

凝汽器海水泄漏处置不及时会引起汽轮机积盐,严重时影响机组正常运行。某电厂330 MW机组出现了此类问题,海水进入凝结水系统后,汽水品质恶化,各取样点钠离子质量浓度大于1 000 μg/L,最终因机组负荷受限被迫停机。分析认为其为汽轮机积盐所致,所积盐分主要为可溶性氯化钠,决定采用过饱和蒸汽清洗法对汽轮机进行不开缸清洗,清洗后汽轮机各部件NaCl残留量低于0.07 g/m²。机组启动14 h后,各项水汽指标均达到GB/T 12145—2016《火力发电机组及蒸汽动力设备水汽质量》要求;机组并网发电后,可满负荷运行。实践表明,因凝汽器海水泄漏所致的汽轮机积盐可采用过饱和蒸汽清洗,方法简单,经济有效。

Application Study on the Treatment of Steam Turbine Salt Deposit in Case Closing Condition

The sea water leakage in condenser will cause salt deposition on the steam turbine unless it is well handled in time. The consequence may become even worse such that the normal operation of the unit will be affected. This kind of problem occurred in a 330 MW power plant before. The steam-water quality deteriorated with the Na⁺ mass concentration of every sampling points exceeding 1 000 μg/L after the sea water leaked into the condensate system. Thus the generation unit had to be shut down due to the load limit. In this paper, the analysis concludes that the problem is caused by the salt deposition on the steam turbine, with soluble NaCl as the major ingredient. Then it is decided to clean the turbine with supersaturated steam without opening the cylinder case. After such cleaning procedures, the content of NaCl on all parts of the turbine is reduced to less than 0.07 g/m². In addition, after startup of the unit for 14 hours, the steam-water quality meets all the requirements of GB/T 12145—2016 Quality criterion of water and steam for generating unit and steam power equipment, and the unit can operate at full load when it is connected to the power grid. The practice shows that the salt deposition on turbines induced by sea water leakage into the condenser can be cleaned by using supersaturated steam, which is proved to be economical, effective and easy to implement.