Corrosion control technology company Cortec has developed an alternative to nitrogen blanketing for easy, effective corrosion protection of void spaces, VpCI-337.
Nitrogen purge or blanketing protects metal void spaces from corrosion. However, nitrogen gas is expensive, the technique requires a constant pressure of nitrogen with an airtight seal, with a need for continual monitoring, and leaks pose a suffocation hazard to staff.
VpCI-337 is a waterborne, vapour-phase corrosion inhibitor that is applied by fogging into metal void spaces. The inhibitors diffuse throughout the void and condense on metal surfaces to form a protective molecular layer. This layer inhibits the corrosion reaction on the metal surfaces even in the presence of oxygen and residual moisture. The space must be completely closed for the corrosion inhibitors to be effective, but an air-tight seal is not required as for nitrogen purge.
The system can be used for large items such as heat recovery steam generators all the way to small crates of metal parts. It has been used for the one-year protection of aboveground storage tank (AST) internals at a sulphur recovery plant, the temporary protection of fuel tanks in retired aircraft stored outdoors during museum renovation, and the internal preservation of pig receivers enroute from construction yard to offshore installation site, amongst other things.
