Kathy L. Fullerton

PROCESS ENGINEERING STUDIES OF THE PERCHLOROETHYLENE COAL CLEANING PROCESS

ABSTRACT The perchloroethylene coal cleaning process has proven to be very effective in removing both organic and pyritic sulfur from high-sulfur coals. The process removes 30%- 70% of the organic sulfur and 90%- 99% of the pyritic sulfur with very little loss (<1.0 wt%) of hydrocarbons and their heating value. The process has been investigated on a bench- scale and a fully continuous, mini-pilot scale (5 kg/hr). This paper discusses scientific and technological issues related to the process engineering and the reaction chemistry of the process. The objective of this paper is to report the status of the process development and to address the important issues of the process commercializability.

Selective precombustion desulphurization of Ohio coals using supercritical fluids

Abstract Desulphurization of coal involves the removal of both the inorganic and organic forms of sulphur. Several physical and a few chemical methods are available for the removal of inorganic sulphur. Removal of organic sulphur requires the use of chemical cleaning methods. This paper presents the results of a sulphur removal technique that employs supercritical fluids. The results obtained from the use of methanol-water mixtures as solvents are examined. The solvent composition in this desulphurization technique can be tailored to selectively reject sulphur without significantly reducing the calorific value of the treated coal. The sulphur-containing organic species in the liquid product from the desulphurization experiments have been characterized using wet chemical methods and g.c.-m.s. analysis.

Characterization of Desulfurization Extracts from Midwestern U.S. Coals

ABSTRACT Coals from Midwestern States were extracted using two different processes, viz., a supercritical extraction process and a perchloroethylene coal refining process. The objectives of these processes are the selective removal of sulfur and nitrogen compounds from high-sulfur coals. The solvent extracts were analyzed using gas chromatography/mass spectrometry as well as wet chemical analysis. The extracted organosulfur compounds varied, depending upon the extraction process, extraction conditions, type of solvent, type of coal, and degree of weathering. The experimental results are compared among the types of coal as well as among the different processes, from viewpoints of chemical and molecular interaction.

Study of the biological destructive separation of hazardous contaminants from town gas soils

Abstract Soil contamination from hazardous materials has existed since the beginning of the industrial age. At that time, unwanted liquid products were disposed of by dumping into unlined pits. Today, the chemical industry is faced with cleaning up these old hazardous waste sites as well as any new site. The hardest part associated with successful soil remediation is the separation of the adsorbed contaminant from the soil. Current research has demonstrated promising results for the destructive separation of hazardous contaminants using bioremediation. This paper addresses the process and results for biological destruction of contaminants from a town gas soil using Mycobacterium sp.

Supercritical extraction of organosulfur from coal using acetone-water mixtures

Abstract Binary mixtures of acetone and water at their supercritical conditions have been investigated for their ability to remove organic sulfur from high sulfur Midwestern coals. The reduction of organic sulfur from Ohio 5/6 and Indiana 5 coals has been as high as 61% (based on a BTU basis) The experiments have been carried out following a statistical experimental design and the optimal process conditions and discerning characteristics of the process have been identified. The solvent composition and the extraction conditions can be tailored in such a way as to selectively remove sulfur and further increase the calorific value of the treated coal.

CHEMICAL COMPOSITION OF OIL SHALE II. DEPENDENCE ON THE EXTRACTION PROCESS

ABSTRACT Eastern and Western U.S. and Australian oil shales were retorted in a fixed-bed, bench-scale retorter, using nitrogen and carbon dioxide as sweep gases. The resulting shale oils were chemically characterized by GC/MS techniques. Shale oils extracted by nitrogen and carbon dioxide retorting processes were found to have different chemical compositions, even when applied to the same oil shale samples. The extraction process dependent nature of shale oils is fully assessed in this paper and the information may be used for comparison among various extraction processes as well as for choosing appropriate upgrading processes for the crude shale oils.

Ligand assisted desulfurization of lignite using the perchloroethylene coal refining process

The perchloroethylene coal refining process was used on North Dakota lignite coal. Effects of extraction time, perchloroethylene :coal ratio and artificial weathering were studied to determine their effects on the removal of organic sulfur. The artificial weathering conditions used were found to be too harsh and caused a decrease in the amount of organic sulfur removed, unlike normal weathering conditions. Additional studies were done involving various ligands, and showed that the addition of certain ligands during the process aided in the extraction of organic sulfur from the coal.

STATISTICAL ANALYSIS OF ORGANOSULFUR EXTRACTION DATA OF OHIO 5/6 COAL USING THE PERCHLOROETHYLENE COAL CLEANING PROCESS

ABSTRACT The perchloroethylene coal cleaning process removes both organic and pyritic forms of sulfur using perchloroethylene as the solvent medium. The effect of process variables including temperature, extraction time, solvent to coal ratio and particle size of coal has been studied by a systematic 24 full factorial experimental design with a single replicate. The process was found to be strongly dependent on the type of coal. Hence, this variable was controlled by choosing one single type of coal, i.e., Ohio 5/6 (1:1 mixture of Ohio 5 and Ohio 6 coals) throughout this entire investigation. The significant effects and interactions have been quantified by F-tests. The estimates of significant effects have been obtained by Yates algorithm. Residual probability and normal probability plots have been obtained to test model adequacy. Finally, a computational model has been developed to predict the organosulfur extraction efficiency of this coal at various values of process variables. The parity plots conclud...

Friction and Wear Testing for Coal Slurry Fuel Development

ABSTRACT Friction and wear characteristics of coal slurries in transportation and atomization/firing systems are areas of concern in considering their use as substitutes for neat liquid fuels. The main wear phenomena encountered in slurry fuel usage are erosive and sliding wear of metal surfaces in contact with the coal slurry. Laboratory experiments have been devised and carried out to characterize and better understand these slurry wear mechanisms. The dependence of wear on the characteristics of the coal slurry and the properties of the wear surfaces have been studied. Coal slurries prepared from an Ohio coal desulfurized using a novel perchloroethylene extraction process have been studied. A Cameron-Flint reciprocating slider tribometer has been used to study sliding wear phenomena. Erosive wear has been investigated using an impingement type wear tester. The importance of impingement angle of coal slurry on platelet formation during erosion has been determined. Results of This angle corresponding to ...