Mitigating cathodic shielding effect on plant corridor pipelines CP system using computer simulation

In petrochemical plants, feed pipelines are located in the utility area that is called corridor pipelines. Usually these pipelines are buried underground and cathodically protected. An existing cathodic protection (CP) system of 12 parallel pipelines comprising shallow distributed anodes was simulated using commercial software based on the boundary element method. The simulated readings were compared to the field measurements. The purpose of this paper is to verify the hypothesis of uniform potential and current distribution on the pipelines which are electrically bonded and protected by distributed shallow anodes through simulation approach. Then provide the best anodes distribution layout that would provide uniform protection for all 12 parallel pipelines of different diameters. The computer software simulation results show that distributed anode system will offer different protection potentials on each pipeline depending on the distance from the anode, diameter of the pipe and shielding of other pipelines. The results indicated that deep well anode impressed current cathodic protection (ICCP) system would provide more uniform protection to pipelines than distributed shallow anodes layout.