Volume 38, Issue 4 (July 2010)
Coal and Coke Volatile Matter Determination and Reconciliation of Differences in Yields Determined by Two ASTM Methods
For over 2 decades, fuel scientists have tried to reconcile the differences between the coal and coke volatile matter yields obtained using either a pre-heated (950°C) minimum volume vertical furnace (ASTM Method D3175) or a macro thermogravimetric analyzer (TGA) system heated to a final temperature of 950°C (macro TGA systems are those using 1 g or larger samples). This paper will describe experiments designed to help explain the differences in volatile matter yields. Parameters studied include sample heating rates, final temperatures, and pre-drying samples. Factors contributing to the differences between the two methods, such as observed differences between plastic and non-plastic coals and fixation of sulfur as sulfate in the pyrolysis residues, will be explained. Results from two interlaboratory studies, each involving over 10 laboratories, and other research projects were used to derive predictive equations to reconcile results from the two methods for determining volatile matter yields in coals.