Date of Award

Spring 1991

Document Type

Thesis

Degree Name

Master of Science in Environmental Science - (M.S.)

Department

Chemical Engineering, Chemistry and Environmental Science

First Advisor

Henry Shaw

Second Advisor

David Kafkewitz

Third Advisor

Richard B. Trattner

Abstract

Sulfur removal from coal before combustion is of considerable interest to avoid emission of oxides of sulfur(SOx). Chemical and physical methods have been developed for removing the inorganic sulfur component in coal. This component is generally associated with pyrites(FeS2). However, no commerical methods have been developed for the removal of the organic sulfur conponent. This study describes microbial methods for removing organically bound sulfur from coal. The specific goals of this study were to ascertain whether a robust biologically active population such as activated sludge biomass can remove organic sulfur from coal and to devise sulfur analytical methods that are less cumbersome than the accepted standards for screening research results. Dibenzothiophene is used in isolating microorganisms that use sulfur as the sole source for growth. It was found that about 55% sulfur can be removed by activated sludge in shaker flasks from a coal which was previously treated to remove inorganic sulfur(IBC-108). A no cycling leaching reactor with activated sludge removed 50% sulfur from the same type of coal. Almost 72% sulfur is removed by A-i, S-Dl, T3-2 and Ar-i mixed cultures. It was also found that about 25 to 29% sulfur can be removed by different cultures from a commercially prepared washed coal in which the pyritic and organic sulfur have not been altered. The application of ion-chromatography and atomic spectrometry in analyzing sulfate, pyritic sulfur, organic sulfur and total sulfur following ASTM extraction can achieve easier and quicker sulfur determinations without sacrificing accuracy and reproducibility.

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