Investigations in coal chemistry: Advancements of analytical techniques and reactive oxidative desulfurization

Coal is this country's most abundant natural resource. In the future we will need to use it as an economical form of energy and as a chemical feedstock. Unfortunately, a high fraction of our coal is high in sulfur content. Therefore, to effectively use coal without detrimental environmental results, inexpensive coal desulfurization techniques will be required. The removal of sulfur from coal provides a challenging problem, not only in the chemistry, but also in the analysis of the reaction byproducts. Therefore, this research addressed both the development of an analytical technique for the analysis of high molecular weight organosulfur species (possible products of coal desulfurization reactions) and the advancement of coal chemistry based on oxidative desulfurization.; Sulfur is exceedingly difficult to remove from the coal matrix. Chemical methods such as reactions with molten sodium hydroxide, potassium hydroxide/sodium hydroxide mixtures are being seriously evaluated. These techniques are not cheap, easily applied, necessarily safe, or well understood. We are studying the removal of organic sulfur from coal by reactive oxidation. This poster demonstrates the use of capillary GC/IR/MS for the analysis and characterization of the desulfurization process.; The particular scheme studied is desulfurizing coal through the oxidative reaction of the organosulfur compounds present in the coal matrix with copper chloride. This reaction was first demonstrated in acidified water. Unfortunately, the initial studies in this reaction were inconclusive. In addition, the proposed desulfurization pathway was unclear. We have further studied the mechanism of this redox reaction. The reaction process has been characterized with respect to activation energy, reaction rate, and overall completeness of reaction. With this knowledge, the reaction will be transferred from the aqueous phase to the supercritical phase. We expect to gain the advantage of increased reaction rate and potentially a reduction in the activation energy due to the increased diffusivity and selective solvation capabilities of supercritical fluids.; The ability to elucidate both qualitative and quantitative information on the products of the reactive desulfurization of coal and model organosulfur compounds has proven to be a considerable challenge. The analytes of interest are often present in a large range of concentrations as well as being entangled in a matrix composed of an exceedingly wide assortment of organic compounds. The complex nature of this problem has required the use of a highly efficient separation system coupled with a serial detection scheme in which complementary information is attained from each detector. The techniques chosen for this investigation was the method of capillary GC/IR/MS, SFC/SCD, and SFC/MS. These complimentary detection schemes provided a large database of information on which both the composition and structure of the products could be easily determined.