Corrosion Assessment in a Hybrid Cathodic Protection System

Abstract

This paper presents the diagnostic corrosion study in a pipeline system that begins in a superficial installation and is destined for the beach area of ​​the Gulf of Mexico, the pipeline system consists of 4 pipelines: D-1, D- 2, D-3 and D-4. The methodology used in this work was based on indirect studies, applying the CIS technique and physical inspection of cathodic protection facilities, with the purpose of knowing their current situation. The section evaluated in this study includes 5 kilometers for each pipeline, considering the potential measuring post 00 + 000 where there are insulating joints in the pipelines until arriving at a beach arrival where the monoblock joints that delimit the cathodic protection system are located. The NRF-047-PEMEX-2007 standard is used, based on compliance with the -0.850 volts criteria in the right of way under study. Galvanic anodes in some lines are operating which show landings in the printed current and minimize the difference between ON and OFF, however, in some cases they are already out of operation which is reinforced by the printed current, achieving the cathodic protection by printed current. The results showed that the pH of the kilometer 0 + 000 to 5 + 000 in the path of the pipelines is in the range of 4 and 8, so in this case the corrosion rate is relatively independent of the pH and does not accelerate the corrosion process in the electrolyte.