The potential exists for predicting organic sulfur (S_o) contents of specific macerals within a coal based on total S_o content of the coal, rank of the coal, and maximum reflectivity in oil (R_o) of the macerals in question. In the past, determination of S_o content of specific macerals necessitated either a microanalysis technique, such as electron probe microanalysis (EPM), or analysis of maceral separates. Ten coal samples ranging in rank from low volatile to lignite and total S_o content from 0.47 to 4.51 wt. % were studied. Within each of the 10 coals, approximately 100 macerals ranging from the lowest reflecting exinites to the highest reflecting inertinites were analyzed for S_o content (using EPM techniq es) and R_o (using petrographic techniques). For each coal, log of maceral S_o content was plotted versus log of maceral R_o, and a linear regression of the data points was performed. On a three-dimensional plot, slopes of the 10 linear regressions were plotted versus the respective coal ranks versus the respective coal total S_o contents. Results indicate that relationships between S_o content and R_o of macerals within a coal are dependent on both the rank and total S_o content of the coal. As total S_o content of a coal equals S_o content of the vitrinite in that coal, the results suggest that predictive relationships exist between maceral S_o content, maceral R_o, coal total _o content, and coal rank that may allow determination of maceral S_o contents without the need for microanalysis.

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