Flange Corrosion… Eating Away at Profits
In California, one client reported that a third of all flanges opened in their HF Alky turnaround had to be replaced due to advanced flange corrosion.
In Texas, a major refinery replaced 400 flanges in a single turnaround due to flange corrosion and leaks.
Flange corrosion occurs when anhydrous hydrogen fluorine combines with water to form aggressive hydrofluoric acid. Since aqueous solutions are used for purging, pressure testing and neutralizing HF Alky units, any residual water that may have seeped past the gasket and remains trapped against the flange faces is a potential source of corrosive activity. The only effective way to battle this problem is to make sure it can’t get started in the first place.
Traditional spiralwound gaskets with inner rings have difficulty sealing the inside of the flange from this kind of intrusion. (CLICK HERE to see how a spiralwound gasket registers in a standard flange.) The lack of gasket compression on the inner throat of the gasket limits the deformation that is essential to sealing off the flange faces.
The Barrier Pillow is permanently joined to the gasket via the Attachment Ring, so it cannot accidentally be dislodged.