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Hot-water drying of a lignite slurry in water. [M. Sc. Thesis]

Technical Report ·
OSTI ID:6294716
Removal of moisture from lignite was studied by heating North Dakota lignite in water slurry 200/sup 0/ to 285/sup 0/C using -100 to +140 US mesh particles in three different slurry concentrations (weight solid-to-liquid ratios) of 1/1, 2/1, and 3/1. The lignite containing 33% inherent moisture, was heated in an autoclave, held at the drying temperature for 15 minutes, and then cooled to room temperature. Residual gas obtained was collected and analyzed. The slurry was then removed and filtered to determine final moisture content of the coal. The content of various metals was determined. Selected lignite samples were analyzed for total acidic groups, gross heating value, and ash content. Ultimate analysis was conducted on five of the product lignite samples. The slurry concentration was shown to not significantly affect moisture reduction. Moisture reduction, which ranged from 25 to 75%, varied linearly with drying temperature according to the empirical equation given in the temperature range studied. An empirical equation was also determined for calculating the final moisture content of a coal after hot water drying. Ash content did not change significantly but sodium content of the lignite was reduced during hot water drying. As the drying temperature increased carbon dioxide formation, gross heating value, and acid group decomposition increased. The equilibrium moisture content of a hot water dried lignite decreased as the drying temperature increased. Hot water dried lignite showed a 6 wt % increase in moisture content in moisture reabsorption tests.
Research Organization:
North Dakota Univ., Grand Forks (USA)
OSTI ID:
6294716
Report Number(s):
DOE/FC-TH-1; ON: DE83010811
Country of Publication:
United States
Language:
English