THERMAL UPGRADING EFFECT ON OXYGEN DISTRIBUTION IN LIGNITE

The results of a study aimed at evaluating the effect of an evaporativ e thermal treatment on the distribution of the oxygen-bearing function al groups in a lignite are discussed in this paper. The lignite was th ermally treated at varying temperature (200-500-degrees-C) in three di fferent process media (nitrogen, steam, and products of combustion at 15% excess air (POC-15)). The effect of the treatment on the oxygen fu nctional groups was evaluated by wet chemical techniques. A steady dec rease in -OH and -COOH groups with increases in treatment temperature, with a relatively small change in the > C = O group were observed. Th e effect of using different process media was not significant, even in the case of excess air. The phenolic -OH group was found to correlate best with the equilibrium moisture content of the coal.