Sulfur removal from coal by oxydesulfurization using alkaline solution from wood ash

Abstract

Some high sulfur coals were extracted with an aqueous alkaline solution obtained from the water soluble fraction of different wood ashes. By this method, high sulfur removal from lignites was possible. The effects of temperature, amount of wood ash used, partial pressure of oxygen, extraction time and stirring speed were studied in the ranges 350–525 K, 10–35 g, 0.0–1.7 MPa, 10–60 min and 200–600 min −1, respectively. The extents of pyritic and organic sulfur removal were investigated. By using oxygen, desulfurization increased rapidly from 20.9, 26.2, and 9.8% to 73.2, 88.9 and 25.2% under 1.7 MPa partial pressure of oxygen at 477 K at 500 min −1 stirring speed for 30 min stirring time for the total sulfur content, pyritic sulfur content and organic sulfur content removals, respectively.