Secondary system chemistry control commonly employs which set of processes?

• A. Ion exchange; Filtration; Steam Generator Blowdown
• B. Distillation; Crystallization; Electrolysis
• C. Sedimentation; Filtration; Adsorption
• D. Chlorination; UV; Ozonation

Answer: (A)

Maintaining the chemistry of the secondary system relies on controlling dissolved ions, removing particulates, and diluting or removing concentrated impurities. Ion exchange precisely removes unwanted dissolved ions that raise conductivity and promote corrosion, making the water inside the loop more protective for metal surfaces. Filtration physically removes particulates that can foul heat-transfer surfaces or act as sites for corrosion. Steam generator blowdown periodically removes a portion of concentrated boiler water to keep dissolved solids from building up, which helps prevent scale, corrosion, and drift in the downstream steam and condensate system. Other options mix processes that aren’t typically used together for secondary-loop conditioning or rely on disinfection methods that aren’t standard in this closed, continuous system.