Abstract: 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.

Key words: thermal power generation, condenser, sea water leakage, steam turbine, salt deposition, cylinder-closed cleaning, supersaturated steam, cleaning