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Theoretical Study of Corrosion of Corrosion-Resistant Alloys in Chemical Processes Environments including Mixed Acids and Salts using a Mechanistic Model

Product Number: 51321-16479-SG
Author: Ali Eslamimanesh/ Andre Anderko/ Malgorzata M. Lencka
Publication Date: 2021
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Corrosion-resistant alloys (CRAs) are often employed in aggressive environments including pure acids as well as their mixtures with or without salts to mitigate corrosion risks. However, corrosion behavior of such alloys in wide ranges of process conditions needs to be reliably predicted. In this work, a previously developed model database is extended and refined to study the corrosion behavior of a group of nickelbase alloys (22, 28, 276, 625, 825, and 2550) and a martensitic stainless steel (S13Cr) in systems relevant to chemical processes, particularly in acids and their mixtures. The computational framework comprises a thermodynamic model for predicting speciation and an electrochemical model for predicting alloy dissolution due to anodic and cathodic processes. The framework also includes a repassivation potential model for localized corrosion. A comprehensive database of relevant experimental data from the literature has been collected in order to refine the parametrization of the model. The same modeling framework has been used to evaluate localized corrosion of the alloys in systems relevant to oil and gas production by calculating corrosion rate, corrosion potential, and repassivation potential as a function of environment speciation, temperature, pH, and partial pressure of gases including CO2 and H2S. The results show acceptable accuracy of the model in representing the literature data.

Key words: Corrosion resistant alloys, acid corrosion, salts, nickel-base alloys, electrochemical modeling, chemical processes environments, localized corrosion

Corrosion-resistant alloys (CRAs) are often employed in aggressive environments including pure acids as well as their mixtures with or without salts to mitigate corrosion risks. However, corrosion behavior of such alloys in wide ranges of process conditions needs to be reliably predicted. In this work, a previously developed model database is extended and refined to study the corrosion behavior of a group of nickelbase alloys (22, 28, 276, 625, 825, and 2550) and a martensitic stainless steel (S13Cr) in systems relevant to chemical processes, particularly in acids and their mixtures. The computational framework comprises a thermodynamic model for predicting speciation and an electrochemical model for predicting alloy dissolution due to anodic and cathodic processes. The framework also includes a repassivation potential model for localized corrosion. A comprehensive database of relevant experimental data from the literature has been collected in order to refine the parametrization of the model. The same modeling framework has been used to evaluate localized corrosion of the alloys in systems relevant to oil and gas production by calculating corrosion rate, corrosion potential, and repassivation potential as a function of environment speciation, temperature, pH, and partial pressure of gases including CO2 and H2S. The results show acceptable accuracy of the model in representing the literature data.

Key words: Corrosion resistant alloys, acid corrosion, salts, nickel-base alloys, electrochemical modeling, chemical processes environments, localized corrosion