A COMPARISON BY STABLE-ISOTOPE MASS-SPECTROMETRY OF COAL OIL COPROCESSING UNDER SEVERE-HYDROTREATMENT AND THERMAL CONDITIONS

The C-13/C-12 ratios of saturated, aromatic, polar and asphaltene frac tions produced by coprocessing of Point of Ayr coal with heavy petrole um residues under severe hydrotreatment conditions were measured by is otope ratio mass spectrometry. The incorporation of coal carbon into t he different fractions was assessed after corrections for catalytic hy drocracking of the end members and for retrogressive reactions. For ar omatic, polar and asphaltene products, incorporation of coal carbon wa s similar to that previously observed for thermal coprocessing and was independent of the oil used. An increase in the saturated fraction du ring severe hydrotreatment is attributed to hydrothermolysis of bound long alkyl chains, and is consistent with gas chromatographic analysis .