Effects of flexible anodes on the potential distribution of the exterior of adjacent tank bottoms

Abstract

A mathematical model for the potential distribution of adjacent tank bottoms under cathodic protection was established as a function of factors that affected the potential distribution. Laboratory experiments were conducted to determine the boundary conditions at the cathode to be used in the mathematical model. A finite element model was solved by means of the commercial software COMSOL. Five parameters have been considered: the distance to the adjacent tank, tank diameter, resistivity of the medium, surface condition of the tank bottom, and anode characteristics. The results showed that the potential of the tank bottom protected by flexible anodes was only slightly affected by the adjacent distance. Furthermore, flexible anodes could effectively decrease the interaction between tanks. With the increase of the burial depth of the anodes, the potential distribution of the adjacent tank bottom reached a steady state. The maximum relative error of the model was 5% and the model was validated by means of field tests.