Publication Date

12-1993

Advisor(s) - Committee Chair

John Riley, Lowell Shank, Wei-ping Pan

Degree Program

Department of Chemistry

Degree Type

Master of Science

Abstract

By optimizing parameters including temperature, reaction time, reagent concentration and pressure, the optimum conditions for the mild oxydesulfurization of coals were determined to be 150°C-200"C and 10 atmospheres oxygen in aqueous slurries of coal reacted with 1 M NH4OH for 1.5-2 hours. The total amount of sulfur removed from -60 mesh coals ranges from 51% to 78% with a mean of 64%, while the amount of inorganic sulfur removed from the coals ranged from 66% to 91% with a mean of 77%. The amount of organic sulfur removed from the samples ranged from 36% to 50% with a mean of 43%.

Thermal analysis of raw and cleaned coals was carried out. By using a heated gas line to connect the thermal gravimetric analysis to the Fourier transform infrared instrument (TG/FTIR), the main products from the combustion of raw and cleaned coals were found to be CO2, H20, and SO2. The IR spectral data for SO2 were collected at 1375 cm' throughout the combustion process for raw and cleaned coals. The temperatures for aliphatic, pyritic and aromatic sulfur oxidation were determined to be 320°C, 420°C, and 470°C, respectively. Based on the thermal analysis experiments, an instrumental analysis method for the determination of pyritic sulfur was designed. The amount of pyritic sulfur determined the TG/FTIR method compared favorably to data obtained using the ASTM D 2492 method.

X-ray absorption fine structure (XAFS) spectra of selected samples were obtained by Dr. Frank Huggins at the University of Kentucky. These spectra supported the results obtained in the oxydesulfurization and TG/FTIR experiments.

Disciplines

Chemistry | Physical Sciences and Mathematics

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