Corrosivity of anhydrous ethanol, hydrated ethanol and fuel E25 (25% ethanol/75% gasoline)

The objective of the work was to study the corrosion of API 5LX 46 and API 5LX 65 alloys, used for pipelines, in anhydrous ethanol, hydrated ethanol and brazilian fuel (E25) through laboratory immersion tests, NACE TM-0172 tests and dynamic tests (corrosion loops). Based on the results of this study, it was concluded that it is advisable that the internal surface of hydrated ethanol storage tanks be painted in order to avoid the corrosion of the internal walls which, despite being incipient, determines color changes which is unacceptable in the market. Furthermore, in pipelines used only for ethanol transportation, the painting of the internal walls of the tubes is not necessary because both the anhydrous ethanol and the hydrated ethanol are not aggressive to the steel, as long as the relative movement of the liquid is guaranteed. Finally, in pipelines used for ethanol and for petroleum derivative transportation, it is advisable that the internal surfaces of pipes be painted in order to avoid the contamination of the ethanol (anhydrous and hydrated) which makes the ethanol aggressive to the steel and changes its color (unacceptable in the market).