Implementation of water chemistry in fossil power plants with drum boilers and in combined cycle/HRSG plants

Current water chemistry practice at fossil power plants with drum-type boilers and heat recovery steam generators includes ammonia dosing into the feedwater train and sodium phosphate or sodium hydroxide into the boiler water. The issues and impact on equipment with the use of phosphate or sodium hydroxide boiler water treatment, as well as optimum conditions for the use of these chemicals are discussed. Another operational issue of boiler unit is associated with flow-accelerated corrosion (FAC) of material, especially in the low-pressure circuit. The major reasons for boiler failures are outlined, with the data on FAC failure locations. An effect of oxygen and ammonia on boiler corrosion processes is discussed.