Naphthenic acid corrosion of API 5L X70 steel in aqueous/oil environment using electrochemical surface-resolved and analytical techniques

Author(s)

Silva, Rejane M. P. ; Suffredini, Hugo B. ; Bastos, Ivan N. ; Santos, Luis F. ; Simoes, Alda M. P.

• Document type: Journal article
• Source: Electrochimica Acta; v. 407, p. 12-pg., 2022-03-01.

Abstract

Naphthenic acid corrosion of steel is studied in crude oil/aqueous phase system at ambient temperature, using a biphasic stagnant liquid without emulsification, by means of electrochemical measurements and surface analysis. The in-situ electrochemical impedance is assigned to the processes occurring at the aqueous phase. Corrosion occurred only in the region of the aqueous phase, as crater-shaped pits that eventually coalesced, generating a nearly uniform attack in the vicinity of the oil phase. The impedance values, normalized to the aqueous region only, reveal corrosion rate increasing with the ratio of crude oil/water. Despite the localized character of the anodic oxidation, the iron naphthenate corrosion products became partitioned between the two phases. Surface-resolved electrochemical techniques in aqueous solution revealed enhanced activity of the regions pre-exposed to oil. (c) 2022 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 13/19903-0 - Kinetical and thermodynamical processes in water/oil interfaces: a fundamental study
• Grantee: Rejane Maria Pereira da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/10526-0 - Fundamental Electrochemical Studies in Oil / Water Interfacial Systems Applied to Corrosion Studies
• Grantee: Rejane Maria Pereira da Silva
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate