Corrosion Control on Tank Bottoms Within Spill-Containment Systems

摘要

Throughout industry today, modern vertical aboveground storage tanks (ASTs) are being situated over spill-containment barriers that isolate the undertank environment from all external effects (Figure 1). Until recently this undertank area was open to the natural soil environment. With the introduction of leak control plastic liners, however, the undertank environment now is a container in its own right. The undertank design primarily is based on structural support of the tank-including a concrete ring support with a liner encompassing the sand, cathodic protection (CP) system, and the tank bottom (Figure 2). The closed nature of this system causes the application of CP in this environment to differ from that on pipelines because the chemistry generated by the CP within the liner is contained. In contrast, the piping typically is exposed to the essentially endless natural soil environment that allows physical chemical effects to diffuse and dissipate.