FURTHER-STUDIES OF GIESELER FLUIDITY DEVELOPMENT IN NEW-ZEALAND COALS

The hydrogen donor ability of fresh samples of a Webb coal with high Gieseler fluidity is shown to be greater than that of samples of the same coal after oxidation has caused a significant decline in fluidity. Model compounds containing hydrogen donor sites similar to those in coal are found to donate hydrogen when heated through a Gieseler temperature profile and to undergo oxidation at these sites under the conditions used to destroy fluidity in coals. The addition of sulphided metal catalysts is found to destroy Gieseler fluidity. The results support the theory that a major factor in fluidity development is a supply donor hydrogens involved in the generation of low molecular weight 'solvating' species.