Effects of organic liquids on coking properties of a high-inert Western Canadian coal
The effects of organic liquids (perchloroethylene, bromoform) typically used in float/sink gravity separations (specific gravity 1.4-1.8) on the fundamental properties of a high-inert Western Canadian metallurgical coal and its resultant coking propensity were examined. Over a 6-month period, untreated (control) and treated coal was characterized using a wide range of analyses including elemental chemistry, FTIR spectroscopy and thermal rheology. The coking ability of the coal was assessed through carbonization trials in both a small-scale sole-heated oven (12.5 kg capacity) and in a pilot-scale movable wall oven (350 kg capacity) with measurements of coke ASG, CSR/CRI and textures. Coal treated in organic liquids was found to exhibit more change in terms of its elemental chemistry (van Krevelen H/C-O/C plot), surface chemistry (FTIR) and rheology (Fluidity and Dilatation) when compared to untreated coal. After a storage time of 1 month, coals were carbonized. The coke resulting from treated coal showed a dramatic degradation in coke quality, as evidenced from decrease in coke CSR, ambient strength, yield and effective coking rank assessed via coke petrography. Further storage time (1-6 months) resulted in minor changes in coke quality showing that the greatest changes occurred within the first month.