Extraction combined catalytic oxidation desulfurization of petcoke in ionic liquid under mild conditions

Abstract

The desulfurization of high-sulfur petcoke under mild condition is a great challenge due to the structurally stable aromatic ring skeleton with a large steric hindrance of sulfur compounds. Herein, by using polyoxometalate ionic liquid [Bmim]3PW12O40 and H2O2 as catalyst and oxidant, respectively, the sulfur content in the petcoke was reduced from 4.46 wt% to 2.85 wt% in green solvent [Bmim]BF4. Moreover, the reaction performed at a mild temperature (80 °C), significantly lower than that in the industrial methods (≥1700 °C). It realized the conversion of high-sulfur petcoke from waste to resources. The experimental results indicated that sulfides in petcoke were oxidized to sulfate, sulfone and sulfoxide, while SO2 was not produced in the process of desulfurization. The possible oxidative desulfurization mechanism was proposed based on the series of characterizations.