In open cooling towers, what is the purpose of corrosion inhibitors?

• A. They sterilize water completely
• B. They increase mineral content
• C. They control water chemistry, reduce corrosion, and limit biological growth by forming protective films and scavenging corrosive species
• D. They color the water

Answer: (C)

Corrosion inhibitors in open cooling towers are used to manage the water chemistry and protect the metal surfaces from corrosion, while also helping control biological growth. They form protective films on metals, which slows down the electrochemical reactions that cause corrosion (a passivation effect). They also scavenge or neutralize reactive species in the water, such as oxygen or other oxidants, which further reduces corrosion potential. By maintaining appropriate chemistry and surface protection, they help keep equipment from corroding and also help limit biofouling.

The other ideas miss the main purpose: sterilizing water completely isn’t what inhibitors do, they don’t increase mineral content, and they don’t color the water.