A Study of Microbiologically Induced Corrosion by Sulfate-Reducing Bacteria on Carbon Steel Using Hydrogen Permeation

Abstract

The mechanism of microbiologically infl uenced corrosion (MIC) on carbon steel (CS) by the bacteria Desulfovibrio desulfuricans subs. desulfuricans was studied using hydrogen permeation, open-circuit potential, and cathodic polarization techniques, in a concentrated culture medium containing bacteria cells (10 7 cell/mL) and ferrous ions (300 mg/L) designed to simulate a condition common in systems for the secondary recovery of crude oil, characterized by highly contaminated microenvironments that severely corrode iron alloys in a short time period. This research project was carried out using several 24-h experiments to defi ne initial stages of the corrosive process under the conditions indicated. The results evidenced a hydrogen permeation current peak of about 12 µA correlated with a minimum open-circuit potential of -780 mV vs saturated calomel electrode (SCE), 400 min after inoculation. Next, the permeation current decreased abruptly to its base line and the potential increased, stabilizing at -585 mV SCE at 24 h, a condition that is associated with high, similar bacterial activity both with and without cathodic polarization (10 8 CFU/mL and 10 9 CFU/mL), typical hydrogen sulfi de (H 2 S) attack morphology, and a weak iron sulfi de fi lm. These results using CS as the corrodible material, together with those obtained using a palladium strip as previously reported, show defi nitely that the cathodic depolarization theory does not represent the chief mechanism used by D. desulfuricans in the MIC process, whereas sulfi de corrosion together with iron sulfi de products seem to better explain the mechanism of this severe bacterial corrosion problem.KEY WORDS: biofi lms, carbon steel, cathodic depolarization, Desulfovibrio desulfuricans, hydrogen permeation, microbiologically infl uenced corrosion, sulfate-reducing bacteria, sulfi de corrosion

Review on the microbiologically influenced corrosion and the function of biofilms

“…Romero in 2005 [114] worked out the mechanism of sulfate reducing bacteria in MIC of iron. According to his theory the first is the bacterial adsorption and iron sulfide production and then a micro-galvanic cell formation through the metallic surface and the iron sulfide.…”

Corrosion and sulfur-related bacteria

“…Stress corrosion cracking and hydrogen embrittlement are two types of damage often reported (De Romero et al, 2005;Koh et al, 2004). Localized corrosion pits on the metal surfaces can be induced by SRB via the CMIC and/or EMIC mechanisms.…”

A Review of Characterization and Quantification Tools for Microbiologically Influenced Corrosion in the Oil and Gas Industry: Current and Future Trends

“…135 Microbiological degradation of stone was found to be enhanced by the rapid growth of algae, cyanobacteria, and fungi which bore into it by releasing extracellular enzymes and metabolites. 136 Romero et al studied MIC by SRB on carbon steel by using hydrogen permeation, 137 and they observed that the sulfate reducing bacteria Desulfovibrio sulfuricans induces carbon steel corrosion due to the biogenic hydrogen sulfide released as the result of its metabolic processes.…”