LAUSR

Abstract Naphthenic acids corrosion is generally considered to leave no corrosion product on steel surface. However, our prior research demonstrates that a protective oxide scale is formed in corrosion with model acids under stagnant conditions. In present study, the corrosion by model acids and a reactive sulfur compound has been investigated alone and in combination in a flow through system. None of the model acids alone forms an oxide scale. However, mixtures of the acid and sulfur compound form a protective scale consisting of an oxygen-containing layer underneath a sulfide layer. A mechanistic model of corrosion and scale formation is proposed.