DETERMINATION OF COAL REACTIVITY DURING COPROCESSING USING STABLE ISOTOPE MASS-SPECTROMETRY

Abstract The 13 C 12 C ratios of fractions with different functionality (saturates, aromatics, polar aromatics and asphaltenes) separated during mild coal-oil coprocessing runs have been determined by stable isotope ratio mass spectrometry on the CO 2 produced by quantitative combustion. The proportions of coal-derived carbon in the different fractions can be determined from the difference in natural abundance of 13 C between the coal and oil starting materials. The correction of the data for isotope-selective effects between different fractions (based on data from oil-only runs) is discussed. The corrected data support a complex model for the mechanism of coal dissolution, with interactions between the coal reactant and all of the fractions of the soluble run product, together with retrograde reactions incorporating oil-derived carbon into the insoluble coke product.