Desulfurization of coal using formic acid

Desulfurization of preoxidized Illinois Basin coal, IBC-108, with formic acid has been studied using a factorial design with four process variables: temperature, reaction time, amount of formic acid and amount of hydrogen peroxide used in the preoxidation step. Maximum total removal of 74% sulfur was achieved by pre-treatment of 5 g coal with 10 ml hydrogen peroxide followed by reaction with 7.5 ml formic acid at 500 C, in a 300 ml batch reactor. The results show that oxidation with hydrogen peroxide significantly enhances the level of desulfurization that may be obtained with subsequent chemical or thermal treatments.