Petrobras Transporte S.A. – Transpetro Solution for the Minimization of External Corrosion of Thermal Insulated Pipelines for Underground Heated Oil Transportation in Brazil

Abstract

Underground heated oil transportation within the processes of Petrobras/Transpetro is a critical issue because of the need to maintain the temperature of the oil in the pipeline network from the point of origin to destination with as little heat loss as possible. Insulated pipelines using polyurethane rigid foams as insulation have been used for many years for this transportation process. However, instrumentation inspections have shown a severe external corrosion process in some insulated pipelines after a number of years in operation. Due to the extent of the insulated pipeline network in Brazil, this kind of problem was possible to identify only after some leakage emergencies. After a deeper investigation in the field it was verified that the pipe protection and insulation system was not adequate for avoiding the corrosion process. In order to prevent and avoid any greater damage to the environment and mainly to the communities living around these underground pipeline zones, a quick review of the entire methodology was necessary. The focus of this article is to describe the identification of this corrosion problem by field experiences and the solution found by adapting the EN 253 norm for pre-insulated bonded pipe systems for underground hot water networks.