International Committee for coal petrology (1978/79) assessment of ring analysis II exercise data on coal hydrogenation samples

Data assessed indicates a wide variation in results reported for maceral, microlithotype and reflectance determinations for both Australian high vitrinite and high inertinite coals. Petrographic examination of their hydrogenation insoluble char residues indicates that three groups of entities can be identified: undissolved coal and minerals, partially dissolved coal and heat affected liquefaction products. Comparative average reflectance measurements conducted on these entities suggests that for the high vitrinite coal, virtually all of the exinite and intertinite were converted, leaving about 10% partially dissolved vitrinite. In the case of the high inertinite coal, about 50% of the inertinite, 90% vitrinite and 95% exinite were converted. Indications are that inertinite with an average reflectance of less than about 1.4% is converted under the hydrogenation conditions used.