ANALYSIS OF FOSSIL FUELS BY FAST NEUTRON ACTIVATION FOR OXYGEN, NITROGEN, SILICON, AND OTHER ELEMENTS

An analytical procedure for analysis of fossil fuels utilizing the fast 14-MeV neutron activation analysis (FNAA) technique is described, and its applicability to some problems associated with classical coal analysis is demonstrated. A detailed description of the FNAA system is given.; A method for direct determination of oxygen in coal is described and applied to re-examine the "standard method" of measuring moisture in coal. A method for calculating "moisture" content in coal based on accurate determination of oxygen is proposed utilizing a unified sample preparation procedure. Analysis results for several coals show that not all of the "moisture" expelled in air at 105(DEGREES)C is due to water. Oxidation during drying also may be detected.; Oxygen is determined in 33 coals ranging from lignite to low-volatile bituminous coal, and the results compared with "oxygen by difference." Discrepancies are observed. Coals with high sulfur content can be detected and the sulfur estimated. Better material balances are obtained if oxygen in coal ash, in wet coal, and dried coal is determined, permitting a better use of data of the ultimate and proximate coal analyses.; Other elements in coal amenable to FNAA are evaluated. A scheme for analyzing coal for nitrogen, silicon, aluminum, and iron following a single short irradiation is described. Interfering reactions are evaluated and measured. Accuracy and precision is assessed, and the reliability of the measured corrections checked by analyzing NBS standard coals. A procedure is developed to analyze coal for these elements by FNAA using a single packaging step and to assess interferences by instrumental neutron activation analysis (INAA) with thermal neutrons on the very same sample. Several selected coals are analyzed and the FNAA results compared with reported values and INAA results.; The results of this study demonstrate that the FNAA scheme developed for determination of five elements provides reasonable accuracy and precision for coals of different compositions. A brief review of the nature of coal and general problems associated with coal analysis is given.