Date of Award
Master of Science
AN ABSTRACT OF THE THESIS OF Amberly Hope Tobin, for the Master of Science degree in Organic Geochemistry, presented on August 4th 2016, at Southern Illinois University Carbondale. TITLE: OHD PROCESSING OF COAL WASTE MATERIALS MAJOR PROFESSOR: Dr. Susan M. Rimmer This research addresses coal-waste utilization via the OHD process and the implications for both economic and environmental impacts. The goal of this project is to determine if coal-waste products can be processed by the OHD technique. Furthermore, this project will determine what types of products are produced from the coal-waste materials and will compare these to those produced by the OHD processing of raw coal. This research has the potential to be beneficial to the coal industry as OHD would allow production of high-value products from what is currently viewed as a waste material; additionally, this research will provide a way to recycle what is considered a hazardous waste product and provide an incentive to reclaim coal slurry ponds that are an environmental concern. A preliminary suite of grab samples from an active coal slurry pond along with a stream reject sample were obtained in order to determine if these types of materials could be processed via OHD. After these samples were deemed viable in the OHD process, core samples were taken from a large slurry pond. These cores were then ii sampled at 2 ft (0.61 m) intervals. The key analyses performed were geochemical, petrographic, OHD, and GC-MS. Geochemical analysis included carbon, sulfur, moisture, volatile matter, ash, and fixed carbon content of the coal-waste samples before OHD, and provided a basis for comparison with raw coal samples. Petrographic analysis was performed to determine the maceral composition before the OHD processing. The OHD process is the core technique of this research project. The preliminary slurry pond samples were processed in a small semi-continuous OHD reactor. While the stream reject and slurry pond core samples were processed using a continuous OHD reactor, as this type of reactor is best suited for fine-grained slurries. GC-MS was used to examine the OHD liquid products analysis in order to determine the types of compounds present in the final liquefied product; these products were then compared to raw coal OHD products in order to determine their economic potential. Petrography of the coal-waste materials showed that these samples did contain a notable amount of coal; predominantly vitrinites and inertinites were observed in the samples. Geochemical analysis proved that there were significant amounts of organic carbon in these materials, ranging between 25 and 37%. OHD processing was successful on all coal-waste materials, although the continuous OHD reactor tended to work better with the fine-grained slurries than the semi-continuous OHD reactor. The GC-MS analysis of the coal-waste OHD product showed very similar suites of compounds to that of a bulk coal OHD product; in general, almost all major compounds that are found in a typical coal OHD product were also found in the coal-waste OHD products. This suggests that these slurry ponds, which are typically regarded as waste products, could be viable feedstocks for OHD processing.
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