Management of Cooling Water Chemistry of Wet Cooled Power Plants in South Africa

Abstract

Scaling, fouling and corrosion are known to have a substantial effect on the performance of coal fired power plant condensers. There are different treatment processes employed in combination with the in-service mechanical cleaning, however, the treatment processes have some limitations when looking at the cooling water chemistry control and condenser efficiency.The main purpose and focus of the study will be to understand the different treatment process limitations, constrains and optimization parameters. Conditions under which scaling, fouling and corrosion occur will be predicted using the Calcium Carbonate Precipitation Potential (CCPP) index to effectively treat, mitigate and minimise the challenges. CCPP is the calculated mass of calcium carbonate expected to precipitate or be dissolved by water.Coal fired power plants with the desalination process implemented will have better cooling water chemistry control compared to those using a cooling water treatment approach based on neutralisation, clarification through flocculation and coagulation, cold lime softening, ion exchange and blowdown method. With the exception of the cold lime soda treatment, some of the treatment processes are costly and generate concentrated effluents that must be disposed.It is predicted that, cold lime treatment when operated optimally may yield positive results and can therefore be considered as treatment of choice for the control of the cooling water chemistry.