November 2016 – Storage tanks used for product storage in industrial facilities are subject to soil-side corrosion during operation, especially when installed in severe environments. Soil-side corrosion is perceived to be a principal cause of storage tank failure and imposes a major environmental and operational challenge worldwide.
Soil-side corrosion is perceived to be a principal cause of storage tank failure and imposes a major environmental and operational challenge worldwide. With thousands of Aboveground Storage Tanks (ASTs), several techniques have been adopted to mitigate soil-side corrosion of AST floors, such as bituminous/oily sand, Cathodic Protection (CP) systems, and coatings. However, total effectiveness of these techniques, standalone or combined, has been questionable in providing the required protection. The bituminous layer hardens and cracks as it ages, creating a corrosive environment that traps moisture and corrosive species between the underside of the tank floor and construction pad. It has also been shown that this layer when combined with CP shields the cathodic current and renders the CP system ineffective, at least partially.
There is a growing industrial awareness about the advantage of introducing amine carboxylate Vaporphase Corrosion Inhibitors (VpCIs) into the tank pad, which makes Cortec’s CorroLogic a logical answer to the aforementioned challenges. The unique ability of CorroLogic VpCIs to protect areas that cannot be reached by traditional Cathodic Protection makes it an ideal treatment to be used in conjunction with CP or by itself when CP is deficient or absent.
CorroLogic can be added to an AST in several different forms, enabling application during construction of new tanks or while existing tanks are in-service or out-of-service. During construction, CorroLogic pouches can be placed on an AST’s high density polyethylene (HDPE) liner and left to emit VpCIs below the tank surface. If an AST is already in service and needs protection, a CorroLogic Slurry is injected beneath the tank floor through the existing monitoring or leakage detection pipes or through injection pipes post-installed through the concrete ring beam. When a tank is out of service for T&I, CorroLogic Powder is fogged through the tank floor into the under-tank area and allowed to diffuse.