EFFECT OF DIESEL-BIODIESEL-ETHANOL MIXTURES ON CORROSION RATE OF VARIOUS METALS IN THE PRESENCE OF TERT-BUTYLHYDROQUINONE (TBHQ)

For many years, the goal of transitioning from conventional to renewable fuels (bioethanol and biodiesel) has been encouraged by government entities. However, due to the hygroscopicity of ethanol, ethanol/biodiesel blends can accelerate corrosion in metallurgy. Therefore, inhibitors can be added to mitigate corrosion. This research studied the effect of adding ethanol to diesel/biodiesel blends and measured the rate of corrosion on various metals (aluminum, copper, and 304 stainless steel) by the electrochemical impedance spectroscopy (EIS) method. The results indicated the corrosion rate increased with increasing the percentage of ethanol in the blends, and the corrosion inhibition efficiency of tert-butylhydroquinone (TBHQ) decreased upon the addition of ethanol. TBHQ was most effective as a corrosion inhibitor in the B15E5 blend. The inhibition efficiency of TBHQ decrease with the increase of the temperature. The adsorption process and the electrochemical parameters were calculated and discussed.