Corrosion of Steel Pipelines Transporting Hydrocarbon Condensed Products, Obtained from a High Pressure Separator System: A Failure Analysis Study

Abstract

In this paper, the corrosion of steel pipelines transporting hydrocarbon condensed products was studied. Different activities of sampling and analysis were carried out to diagnose the failure causes and to establish a control system for the corrosion problem. The combination of three types of corrosion, including erosion corrosion, galvanic corrosion and microbiologically induced corrosion, was synthetically considered. A serial of experiments were designed to research those types of corrosion. This type of failure was observed in characteristics sites of the pipeline, mainly in direction changes and welding joints. Additionally, localized corrosion was observed in the inner steel wall and distributed along the pipeline, although a tendency was not detected.

Water-Induced Corrosion Damage of Carbon Steel in Sulfolane

“…- Corrosion of carbon steel used in the petroleum industry for pipelines or tanks is mainly caused by the presence of water, corrosive gases (H 2 S, CO 2 and O 2 ), chlorides and microorganisms. The most common form of corrosion occurs when carbon steel comes in contact with an aqueous solution, for instance, when CO 2 is dissolved in water, corrosive carbonic acid is formed [43][44][45][46][47][48][49]. Sulfolane in the presence of water and air also forms an aqueous solution of sulphurous acid [24][25][26].…”

“…For example, an iron carbonate protective layer can be formed on the surface of carbon steel and low-alloy steels (to 9 wt.% Cr) used in the petroleum industry. However, note that fluid movement or the temperature often break down the FeCO 3 layer accelerating corrosion process [46][47][48][49]. It was found that for the water concentration in the range from 1 to 4 vol.%, a protective layer stabilizes the corrosion rate of AISI 1010 steel in sulfolane at a certain level.…”