Analyzing and design of mesh ribbon cathodic protection for aboveground storage tanks

Abstract

Aboveground storage tanks are widely used for storage of liquids. The bottom of these tanks rest on the soil and is prone to the corrosion. Due to the use of geo-membrane liner in some cases, the bottoms of these tanks can only be protected from corrosion by using distributed mesh ribbon anodes. Up to now, there is no an accurate and comprehensive calculation for current distribution in such configurations. For this reason, the spans of the ribbon anodes and conductor bars are mostly chose based on simple and handy formulas, which may not be correct and optimum enough. Therefore, in this paper, the current distribution is calculated based on a 2D model and considering coating and polarization effect and then applied for determining the anodes span. Furthermore, the current attenuation in the ribbons and conductor bars are calculated for determining the spans between the conductor bars. Finally, based on the achieved formulas, two designs are presented and compared and the results of them are validated by Finite element method simulations. The results of this paper could be used for optimum design of cathodic protection systems for bottom of the above ground storage tanks.

Keywords

• Ribbon anodes
• Storage tanks
• Polarization
• Finite element method