VpCI - What are Vapor Phase Corrosion Inhibitors

Cooling Towers

Steam Boiler Systems

Winter shutdown presents a significant corrosion risk for cooling tower systems. Without active circulation, water and moisture can stagnate, leading to accelerated rust formation on metal surfaces. Recirculating vapor phase corrosion inhibitors (VpCIs) is an effective method to protect these systems prior to an off-line period.

💧How Vapor Phase Corrosion Inhibitors Work

VpCIs are a type of chemical that volatilizes and travels through the air to form a thin, protective molecular layer on metal surfaces. In a cooling tower system, this means the VpCI vapor can reach hard-to-access areas like the inside of pipes, pumps, and heat exchangers that would be difficult to treat with traditional liquid-only inhibitors. This vapor barrier effectively isolates the metal from moisture and oxygen, preventing the electrochemical reactions that cause corrosion.

💧Key Benefits

• Comprehensive Protection: The vapor phase action ensures protection of both wetted and unwetted metal surfaces, including areas that are difficult to reach physically.

• Ease of Use: The method is a simple addition to the standard shutdown procedure, requiring minimal extra time or labor.

• Long-Term Effectiveness: The VpCI layer provides durable protection for extended shutdown periods.

• Environmentally Friendly: Many VpCI products are water-based and designed to be non-toxic and biodegradable, simplifying disposal and handling.

By using recirculating VpCIs, operators can ensure their cooling tower systems are shielded from corrosive damage during the winter months, leading to extended equipment life and reduced maintenance costs.

Vapor phase corrosion inhibitors (VpCIs), such as the Boiler Lizard, are used for off-line boiler layup to protect the internal metal surfaces from corrosion. This method is considered a "dry" layup process and is an alternative to traditional "wet" layup methods that involve filling the boiler with a treated solution.

💧How It Works

The Boiler Lizard is a water-soluble corrosion inhibitor that is placed in the empty drum of the boiler. The inhibitor then evaporates and forms a protective molecular layer on all metal surfaces, including those in hard-to-reach areas. This layer prevents oxygen and moisture from reaching the metal, thus stopping the corrosion process. For Feed Water tank protection, a liquid VpCI is added to the tank and the tank is flooded with water for the lay-up.

💧Benefits of VpCI Layup

• Ease of Use: It's a simple, single-step application that requires less labor and time compared to wet layup.

• Complete Protection: The vapor phase inhibitor reaches all parts of the boiler, including tubes, headers, and drums, providing comprehensive protection.

• No Draining Required: The boiler does not need to be drained of a protective solution before startup, saving time and water. The Boiler Lizard's protective layer is volatile and is removed during the initial startup process.

• Environmentally Friendly: Many VpCIs are biodegradable and non-toxic, making them a safer option for both personnel and the environment.

This method is particularly effective for extended layup periods and for boilers that are difficult to dry completely. It ensures the boiler remains in a ready-to-use condition without the risk of corrosion.