Compatibility of Carbon Steel with Isobutanol

As an advanced biofuel, butanol has some benefits over the first generation biofuels (e.g. corn based ethanol) such as higher energy density and lower hygroscopicity. Although it is well known that carbon steel is susceptible to stress corrosion cracking (SCC) in fuel grade ethanol (FGE), there is a lack of information regarding the susceptibility of carbon steel to SCC in isobutanol and its blends with gasoline. This work investigated the susceptibility of a line pipe steel to SCC in 12.5% isobutanol-gasoline blends with three contaminants (1% water, 50 ppm chloride and 75 ppm isobutyric acid). The effect of each contaminant and their possible synergistic effects were investigated. Additionally, electrochemical tests were conducted to investigate the corrosion behavior of carbon steel 1018 in the 12.5% isobutanol-gasoline blends in the presence of all three contaminants.