Fuel Science & Technology International, Vol.12, No.2, 191-210, 1994
SOLVENT DEASHING OF COAL TO GET AN ENVIRONMENTALLY CLEAN AND HIGH CALORIFIC VALUE FUEL BY BATCH EXTRACTIVE REFINING TECHNIQUE UNDER AMBIENT CONDITIONS
Extraction of Samla, Assam and Godavari coal (bituminous coals) and Neyveli lignite in anthracene oil has been studied. About 4 to 36% coal was rendered extractable; the residual coals showed further extractability in quinoline indicating some depolymerization of coal caused by the anthracene oil extraction. The mechanism of the extraction of coal by anthracene oil has been studied by using Phenanthrene and carbazole separately as solvents for extraction. Phenanthrene was found to be a better solvent for extraction and depolymerization. Cetene was also found to be a good solvent for extraction of coal. The residual coals obtained after cetene extraction showed enhanced extraction in quinoline, indicating that coal becomes labile and is depolymerized. The extraction of coal in anthracene oil is due to co-solvency effect of phenanthrene and carbazole and other aromatic and heteroatomic solvents in anthracene oil. Cetene extraction appeared to be controlled by mass transfer effects. Cetene and anthracene oil were found to be good solvents for solvent deashing of coal and offer a means of producing environmentally clean and high calorific value fuels.
Keywords:PRESSURE