Microbiological and Electrochemical Evaluation of Corrosion and Microbiologically Influenced Corrosion of Steel in Ethanol Fuel Environments

An investigation of microbiologically influenced corrosion (MIC) of steels used for the storage and transportation of ethanol fuels is underway.  MIC could occur in local areas of these systems when conditions suitable for life are present, such as during periods of stagnation or during system upsets.  The current study is aimed at evaluating the propensity for MIC under these non-ideal conditions. Efforts to date have included field sampling of ethanol fuel storage and transportation infrastructure for chemical and biological evaluation, microbiological viability and corrosion studies, and electrochemical evaluation of corrosion parameters for simulated fuel grade ethanol (SFGE).  Field sampling has provided insight on the microbial diversity in existing ethanol conveyance systems.  Laboratory investigations have evaluated microbiological viability in high ethanol environments as well as the influence of microbiological activity on corrosion of steel in these environments.  Electrochemical analysis and assessment has characterized the behavior of ethanol, water, and oxygen on corrosion of steel. Results suggest further evaluation of the propensity for MIC in under these situations is required.