Bioethanol is a promising biofuel. But what about the corrosion effects?

Researchers from the University of Chemistry and Technology in Prague researched the corrosion behavior of mild steel in the environment of E85 fuel.

The use of biofuels produced from renewable energy sources can help save the remaining fossil fuels and reduce greenhouse gas emissions. Currently, bioethanol is the most common biofuel applicable for petrol engines. Bioethanol can be produced by fermentation technology from different sugar- or starch-containing feedstocks such as sugar beets, sugar cane, wheat, maize and potatoes.

"The further use of the first-generation biofuels is, however, neither sustainable nor acceptable in the future, especially as a further increase in their production would require more and more agricultural areas applicable for food and/or feed production. Thus, much attention is paid to higher generation biofuels being produced from non-food biomass such as different kinds of agricultural or other waste." says researcher Martin Staš.

The combustion of bioethanol in petrol engines is associated with several problems, with bioethanol corrosion effects on metallic construction engine parts being one of the most serious ones. Electrochemical methods, such as electrochemical impedance spectroscopy, measurement of polarization characteristics have been found to be efficient in studying corrosion effects in metal-EGB systems. However, a fuel environment with a low ethanol content has low conductivity, which can be a limiting factor for electrochemical corrosion studies. Supporting electrolytes can be used to increase the conductivity of such environments. These supporting electrolytes must be inert against the occurring corrosion reactions in order not to negatively affect the obtained corrosion data.

In this study, the results of the testing of the influence of four supporting electrolytes on the distortion of the measured data have been presented. The testing was performed using electrochemical methods in a three-electrode arrangement applied on mild steel-E85 fuel systems.

"In our study, we demonstrated that tetrabutylammonium tetrafluoroborate can successfully be used for short-term corrosion studies. The use of this supporting electrolyte can substantially facilitate electrochemical corrosion studies in less conductive media," researchers conclude.

See more in an original research article published in Science Direct. Text is based on the research text.

More information:
Lukáš Matějovský et al, Electrochemical corrosion tests in an environment of low-conductive ethanol-gasoline blends: Part 1 – Testing of supporting electrolytes, Journal of Electroanalytical Chemistry (2020). DOI: 10.1016/j.jelechem.2020.114879

Provided by University of Chemistry and Technology Prague