Integration of deasphalting and oxidative desulfurization processes for heavy fuel oil desulfurization

In this study, a combined process consisting of solvent de-asphalting followed by continuous ultrasound-assisted oxidative desulfurization (UAOD) was applied for the treatment of heavy fuel oil (HFO). Acetic acid (99 wt.%) and hydrogen peroxide (35 vol.%) were employed as the catalyst and oxidant, respectively. n-Heptane and n-hexane were tested as de-asphalting solvents, while methanol and acetonitrile were used as extraction solvents in the liquid–liquid separation stage. The integrated process exhibited high efficiency in sulfur removal, reducing the sulfur content of HFO to below 5000 ppm. The most effective performance was obtained when n-heptane was used for de-asphalting, combined with ultrasonic desulfurization and subsequent extraction with methanol, which lowered the sulfur content to approximately 5292 ppm.