A comparison by stable isotope mass spectrometry of coal-oil coprocessing under severe-hydrotreatment and thermal conditions

The ¹³C ¹²C ratios of saturated, aromatic, polar and asphaltene fractions produced by coprocessing of Point of Ayr coal with heavy petroleum residues under severe hydrotreatment conditions were measured by isotope ratio mass spectrometry. The incorporation of coal carbon into the different fractions was assessed after corrections for catalytic hydrocracking of the end members and for retrogressive reactions. For aromatic, polar and asphaltene products, incorporation of coal carbon was similar to that previously observed for thermal coprocessing and was independent of the oil used. An increase in the saturated fraction during severe hydrotreatment is attributed to hydrothermolysis of bound long alkyl chains, and is consistent with gas chromatographic analysis. © 1993.