Experimental investigation of the desulfurization of a high sulfur coal with multi-ring sulfurous

Coal desulfurization is imperative to produce clean coal and reduce the emission of harmful gas during combustion. However, organic multi-ring sulfurous in coal is more difficult to remove than inorganic sulfur. Therefore, in this paper, two desulfurization methods, traditional oxidation desulfurization method nitric acid leaching (NAL) and novel reduction potassium tert-butoxide and hydrogen silane desulfurization system (KOSi), were compared to remove the organic multi-ring sulfurous in raw coal sample. The results showed that the total sulfur content reductions of NAL and KOSi were 45.21% and 31.51%, corresponding to the loss rates of calorific value were 10.32% and 5.45%, respectively. The critical factors for the higher desulfurization rate of NAL than KOSi were the decreased particle size, the generation of cracks on the coal sample and the effective removal of sulfones (SN) from thiophene (TP) oxidation. In addition, the carbon macromolecular framework of coal particles could be destroyed in NAL system, resulting in a decrease in C-C and C-H content. This was the main reason that the calorific value loss of NAL was greater than that of KOSi. The consequence of this paper would provide data support for the selection of the desulfurization method for high sulfur coal, especially consisting of multi-ring sulfurous, in terms of indicators and mechanisms.