Chloride effects on the electrochemical degradation of micro-alloyed steel in E20 simulated fuel ethanol blend

Abstract

Biofuels play a major role as a renewable energy source in mitigating global warming. The presence of impurities in fuel ethanol has resulted into certain downsides regarding material compatibility. This work is focused on an investigation of the influence of sodium chloride (NaCl) as an impurity in the electrochemical degradation of micro-alloyed steel (MAS) when exposed to E20 simulated fuel grade ethanol (SFGE) environment. Immersion and electrochemical tests were carried out using NaCl concentrations ranging from 0 to 64 mg/L. Highest corrosion rates were obtained with 64 mg/L NaCl and lowest rates were observed in the zero chloride tests. Chloride was also seen to cause pitting corrosion on MAS. The results of potentiodynamic polarization tests on MAS compared well with mass loss corrosion rates. Analysis of variance (ANOVA) test confirms the significance of the results at 99% confidence, and further showed that there is significant difference between the chloride concentrations. However, from the perspective of corrosion in fuel ethanol, micro-alloyed steel is thought to be compatible with E20 since the determined corrosion rates were very low. Keywords: Fuel ethanol, Corrosion, Micro-alloyed steel, Chloride, Pitting