Studies on the Early Stage of Carbonization of Argonne Premium Coals by Means of High-Temperature ¹³C-NMR

Abstract

Four pristine and two oxidized Argonne Premium Coals have been investigated by in-situ high-temperature ¹³C-NMR. In-situ monitoring for changes of mobility and chemical structure for coals has been successfully accomplished. Characteristic temperatures for coals during the early stage of carbonization were determined from the series of spectra of in-situ high-temperature ¹³C-NMR. It was found that the temperature of minimum of half-width, Tm, and the temperature interval from softening to minimum of half-width, Tsm, correlate to the coal rank for the three lower rank coals tested. It was suggested that aliphatic carbons in coal have a large role for depolymerization and/or polymerization of coals oxidized during heating.