Effect of oil and seawater content in the biocorrosion process of API 5LX60 steel

摘要

This study aimed to evaluate the process of microbiological corrosion and biofilm formation in plates of steel API 5L X60 continuously immersed in static systems containing oil and seawater in different proportions over a period of 90 days. To perform the experiment, systems containing oil and seawater, with levels of water in the proportions of 10%, 20% and 30% were mounted. Coupons from API 5L X60 steel of dimensions 32×10×5 mm were used, which were fixed by the static system of nylon and completely immersed in the fluid. The quantify the sessile microorganisms present in biofilms over time, for the three different concentrations was analyzed. The microorganisms quantified in this study were: sulfate-reducing bacteria, acid producing anaerobic bacteria, total anaerobic bacteria, iron-precipitating bacteria, aerobic acid-producing bacteria, total aerobic bacteria and fungi. To assess the corrosion rate of API 5L X60 steel was used to weight loss technique. The results revealed a strong influence of the amount of seawater in the processes of microbial growth and biocorrosion. The corrosion rate observed was low for the three investigated systems.