Organo-Refining To Produce Near Zero Ash Coals: Determination of Elemental Concentration in Clean Coals

摘要

Coal ash still hinders boilers and equipment during coal combustion and its utilization. The different elements depending upon their characteristic nature affect coal utilization. However, solvent extraction is able to remove the organic coaly matter leaving behind most to almost all of the deleterious elements. In the present paper, five Indian coals were extracted with two different solvent systems. The two systems are N-methyl pyrrolidone (NMP) containing a small amount of ethylenediammine (termed e,N solvent system) and NMP containing a small amount of diethylenetriammine (DETA) (termed NMP DETA solvent system). The clean coal samples showed more than 95% ash reduction. The elements present in raw and clean coals obtained after extraction were determined by means of X-ray diffraction spectroscopy, X-ray fluorescence spectroscopy, and inductively coupled plasma mass spectroscopy. NMP containing a small amount of DETA was found to be a more effective solvent system in comparison to the e,N system both in extraction yield and reduction in major and deleterious elemental concentration. A total of 85-100% of Mg, Al, and Ca could be effectively removed using DETA as the cosolvent with NMP from these coals.