Effect of Introduction of CO2 on the Formation of Biofilms/Biocorrosion in Aisi 1018 Carbon Steel Surfaces Exposed in a Dynamic System

Biofilms are typically composed of water, microorganisms, EPS, retained particles, and dissolved or adsorbed substances. The corrosion process of metals exposed to seawater is characterized by different factors such as temperature, salinity, oxygen concentration, CO₂, H₂S and microorganisms. The oil and gas industries studies the operation of oil well pressurization through CO₂ injection while corrosion by this compound has being studied by various authors. The aim of this work was to evaluate the effect of the introduction of CO₂ on the formation of biofilm/biocorrosion in AISI 1018 carbon steel exposed in a dynamic system. The results showed an increase in the number of sessile microorganisms (cells/cm²) as a function of the increase of CO₂ in the system: aerobic bacteria 9.5 x 10³, 4.5 x 10⁴, 7.5 x 10⁴; anaerobic bacteria 7.5 x 10⁴, 4.5 x 10⁴, 4.5 x 10⁴; SRB 0.9 x 10, 4.5 x 10², 4.5 x 10³, respectively, in the systems without CO₂ addition, with the introduction of 2L of CO₂/min and 4L CO₂/min. The corrosion rates without the introduction of CO₂ was significantly lower in relation to the systems with the CO₂ addition. The corrosion rates increased as a function of the CO₂ increase in the systems.