Improvement of extractive desulfurization for Iraqi refinery atmospheric residual

Abstract

Extractive desulfurization (EDS) process of petroleum fuels via effective solvents has been widely investigated in recent decades and has an excellent future as an alternative technique to HDS process. This study was focused on removal of sulfur compounds from heavy Iraqi atmospheric residual oil (IARO) via EDS process without affecting its other properties. Different hydrocarbon solvents (light naphtha, n-heptane and n-hexane), solvent to oil ratios (4/1, 8/1, and 12/1), extraction times (30, 60, and 120 min), and extraction temperatures (30 °C, 60 °C and 90 °C) were investigated on the precipitation of sulfur in Iraqi atmospheric oil residue. The results were showed that increasing of solvent to oil ratio, extraction times, and extraction temperatures enhanced the performance of EDS process. The experimental results proved that 96% of sulfur compounds were eliminated from heavy residual oil using effective n-hexane as solvent under moderate operating conditions as follow: extraction temperature of 90 °C, extraction time of 60 min, and solvent to oil ratio of 12/1. This study prove that extractive desulfurization via hexane-like solvents at the best experimental conditions can achieve satisfactory sulfur removal efficiency of heavy oil via safe, fast, economically and effective process.