Effects of Mass Transfer and Flow Conditions on SRB Corrosion of Mild Steel

Microbiologically Influenced Corrosion (MIC) is a growing problem in the oil and gas industry resulting in huge financial losses. Sulfate Reducing Bacteria (SRB) are often the culprits although many other microorganisms can also be directly or indirectly involved. From the bioprocess engineering angle, mass transfer and flow conditions are very important in SRB biofilm formation and MIC corrosion rates. Experiments were carried out in a 2-liter electrochemical glass cell bioreactor with a carbon steel rotating cylinder coupon. ATCC 7757 strain of Desulfovibrio desulfuricans was used in this work with the ATCC 1249 medium. Experimental data indicated that mild agitations with a low linear velocity at increased cell growth and MIC corrosion compared to stagnant conditions, because mass transfer was facilitated. However, a high linear velocity exhibited inhibition of cell growth and MIC corrosion. The results have implications in predicting and controlling MIC in pipeline flow systems.