Modeling pitting corrosion in a CO <inf>2</inf> system containing bacteria

Modeling pitting corrosion in a CO 2 system containing bacteria Conference

Garber, JD, Knierim, K, Acuna, J et al. (2008). Modeling pitting corrosion in a CO 2 system containing bacteria . 085451-0854524.

A mathematical approach was taken in order to describe the pitting process in CO 2 corrosion. The hypothesis established was based on a unidirectional pit model which involved nineteen species, one of them (Fe 2+) being diffused from the bottom of the pit. Using numerical methods, a prediction of corrosion rates in the pit, concentrations of the species in the pit and pH profile were determined. The average corrosion pitting rate from CO 2 was found by calculating the corrosion rate at various pit depths. Sulfate reducing bacteria (SRB) on carbon steel has been studied by determining the role of bacteria in conjunction with localized CO 2 corrosion. The influence of temperature, pH, sodium chloride, acetates and sulfates has been analyzed and modeled in a program that calculates CO 2 pitting corrosion rates including the reduction from sulfate to sulfide due to SRB. This bacteria metabolism produces acetate and hydrogen ions which increases the CO 2 pitting corrosion rates. The increased corrosion rate from the bacteria is expressed as a percent enhancement above the CO 2 corrosion model value. © 2008 by NACE International.