Desulfurization of Lakhra coal by combined leaching and catalytic oxidation techniques

Abstract

ABSTRACT Desulfurization of the Lakrah coal was investigated by combined leaching and catalytic oxidation. For leaching various concentrations of different acidic and base solutions including H2SO4, HCl, HNO3, KOH, NaOH, and Na2CO3 were used. Among acids, 0.4 N HNO3 at room temperature and 30 min stirring time, provided about 19.3% of sulfur removal, whereas the base solution of 0.4 N KOH was most effective, decreasing the total sulfur by 29%. The leached coal was subjected to oxidative desulfurization using H2O2 as oxidant. The optimum conditions were found to be 70°C temperature, 60 min reaction time and using toluene as a solvent, which led to decrease in the total sulfur upto 50%. The oxidative desulfurization was further investigated in the presence of Fe loaded on bentonite catalyst. The oxidative desulfurization of the Lakhra coal in the presence of 3% Fe loaded on bentonite clay was enhanced to about 83%.