The economy and population of McDowell County, West Virginia, drastically decreased between 1950 and 1970. The increased reliance of the coal industry, McDowell County's primary industry, on labor saving machinery resulted in a loss of employment opportunities. This study seeks to investigate the reasons for the reliance on coal and the results of the mechanization movement in the coal industry on McDowell County. Using production and employment data of two representative McDowell County coal companies, it is clear that the introduction of continuous mining machines, which combined the cutting and loading of coal into one step, allowed companies to mine more coal with fewer workers. Because the economy of McDowell County was so coal-intensive, the increased unemployment caused by mechanization forced many miners to migrate to such midwestern industrial centers as Cleveland or Columbus.

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005

The thermodynamic behaviours in a PFBC combustor were simulated for the ash from all of the six coals with sand and limestone as bed material. Ash components determined the ash thermodynamic behaviour at high temperature, and each component had different effects. For assessment of the potential for bed material agglomeration, the temperature at which 15% of the ash would become liquid (T15) was calculated with the coal ash, the cyclone ash and the cyclone ash mixed with varying amounts of limestone. Both the bed ash and fly ash, collected from an industrial PFBC plant, consisted of limestone/lime particles with different extent of sulphation, and coal ash particles. The calcium aluminosilicate material formed on the coal ash particles but not on the limestone particles. The aluminosilicate materials appeared to be formed from fine ash and lime particles at some local hot zones in the boiler. The melted materials may glue ash and bed material particle into large particles leading to bed agglomeration and defluidization. Four mechanisms were proposed for the formation of bed material agglomeration in PFBC, which may occur under different conditions. One mechanism explains the bed material agglomeration with the high localized high temperature zone due to the improper design or operation, while the bed agglomeration through the other three mechanisms results from the unsuitable coals burnt in the PFBC combustor. The maximum char temperature and the minimum T15 were used simultaneously to predict the tendency towards bed material agglomeration in PFBC burning different coals. Both char properties and ash properties should be considered during coal selection process for PFBC, to ameliorate the potential problem of bed agglomeration.

The power generation industry in the state of Victoria, Australia stands to gain significantly from process improvements and optimization which can potentially lead to cleaner production of cost effective electricity. The efficient operation of lignite based tangentially-fired combustion systems depends on critical issues such as ignition and combustion of the fuel, which are largely controlled by burner aerodynamics. The geometry of the burner and the ratio of velocities between the primary and secondary jets play an important role in achieving stable combustion, high burnout of fuel, low production of pollutants and control of fouling. Slot-burners are a vertically aligned stack of rectangular nozzles delivering primary fuel and secondary air jets, and are commonly used in tangentially-fired boilers. To obtain a better understanding of the overall combustion process, it is important to understand the aerodynamics of jet development from these burners. The starting point of this research was a CFD investigation of aerodynamics in the near-burner region of isolated rectangular slot-burners, using isothermal conditions, for various secondary to primary jet velocity ratios (φ). Cross-flow was then added to replicate a near-burner flow field similar to that found in a tangentially-fired furnace and the effect of changing φ in the near-burner region of the developing jets was again investigated. Experiments were carried out on an isothermal physical-burner model to obtain mean velocity and turbulent statistics for different nozzle geometries and a range of φ. A computational fluid dynamics investigation of these same jets was also performed to gain further insights into the complexities of flow field with experimental results used to validate CFD predictions. The primary jet substantially deviated from the geometric axis of the burner towards the furnace wall and became very unstable for higher φ. The causes of unfavourable aerodynamics were discussed and suggestions were made on possible remedies for such behaviour. Conventional lignite combustion in a full-scale tangentially-fired furnace was modelled. The model was used to assess the possibility of utilizing a new type of mechanically thermally dewatered (MTE) coal in existing furnaces.

Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2009.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 119-120).

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 170 p. : ill. Includes abstract. Includes bibliographical references (p. 119-137).

Biomass co-firing with coal exhibits great potential for large scale utilization of biomass energy in the near future. In the present work, energy and exergy analyses are carried out for a co-firing based power generation system to investigate the impacts of biomass cofiring on system performance and gaseous emissions of CO2, NOx, and SOx. The power generation system considered is a typical pulverized coal-fired steam cycle system, while four biomass fuels (rice husk, pine sawdust, chicken litter, and refuse derived fuel) and two coals (bituminous coal and lignite) are chosen for the analysis. System performance is evaluated in terms of important performance parameters for different combinations of fuel at different co-firing conditions and for the two cases considered. The results indicate that plant energy and exergy efficiencies decrease with increase of biomass proportion in the fuel mixture. The extent of decrease in energy and exergy efficiencies depends on specific properties of the chosen biomass types. The results also show that the increased fraction of biomass significantly reduces the net CO2 emissions for all types of selected biomass. However, gross CO2 emissions increase for all blends except bituminous coal/refuse derived fuel blend, lignite/chicken litter blend and lignite/refuse derived fuel blend. The reduction in NOx emissions depends on the nitrogen content of the biomass fuel. Likewise, the decrease in SOx emissions depends on the sulphur content of the biomass fuel. The most appropriate biomass in terms of NOx and SOx reduction is sawdust because of its negligible nitrogen and sulphur contents. / UOIT

Hydrogen sulphide is an environmentally hazardous gas which is present in many gas streams associated with oil and gas industry. Oxidation of H2S to sulphur in air produces no bulky or waste material and requires no further purification. Activated carbon is known as a catalyst for this reaction.<p> In this research, a coal-based precursor (luscar char) and a biomass-based precursor (biochar) were used for production of activated carbons by two common methods of activation: physical and chemical activation in which steam and potassium hydroxide (KOH), respectively, were used. Experiments were designed by the statistical central composite design method. Two models were developed for the BET surface area and reaction yield of each activation process. These models showed the effects of operating conditions, such as activation temperature, mass ratio of activating agent to precursor, activation time, and nitrogen flowrate on the BET surface area and reaction yield for each activation method for each precursor. The optimum operating conditions were calculated using these models to produce activated carbons with relatively large BET surface area (> 500 m2/g) and high reaction yield (> 50 wt %). The BET surface area and reaction yield for activated carbons produced at optimum operating conditions showed maximum 7 and 7.4 % difference, respectively, comparing to the values predicted by models.<p> The activated carbons produced at optimum operating conditions were used as the base catalysts for the direct oxidation of 1 mol % hydrogen sulphide in nitrogen to sulphur at the temperature range of 160-205 oC and pressure of 700 kPa. Originally activated carbons showed a good potential for oxidation of hydrogen sulphide by their selectivity for sulphur product and low amount of sulphur dioxide production. To improve the performance of steam-activated carbons, the catalysts were modified by acid-treatment followed by thermal desorption. This method increased the break-through times for coal-based and biomass-based catalysts to 115 and 141 minutes, respectively. The average amounts of sulphur dioxide produced during the reaction time were 0.14 and 0.03 % (as % of hydrogen sulphide fed to the reactor) for modified activated carbons prepared from biochar and luscar char, respectively. The effects of porous structure, surface chemistry, and ash content on the performances of these activated carbon catalysts were investigated for the direct oxidation reaction of hydrogen sulphide.<p> The acid-treatment followed by thermal desorption of activated carbons developed the porosity which produced more surface area for active sites and in addition, provided more space for sulphur product storage resulting in higher life time for catalyst. Boehm titration and temperature program desorption showed that the modification method increased basic character of carbon surface after thermal desorption in comparison to acid-treated sample. In addition, the effects of impregnating agents (potassium iodide and manganese nitrate) and two solvents for impregnation process were studied on the performance of the activated carbon catalysts for the direct oxidation of H2S to sulphur.<p> Sulphur L-edge X-ray near edge structure (XANES) showed that the elemental sulphur was the dominant sulphur species in the product. The kinetic study for oxidation reaction of H2S over LusAC-O-D(650) was performed for temperature range of 160-190 oC, oxygen to hydrogen sulphide molar ratio of 1-3, and H2S concentration of 6000-10000 ppm at 200 kPa. The values of activation energy were 26.6 and 29.3 kJ.gmol-1 for Eley-Rideal and Langmuir-Hinshelwood mechanisms, respectively.

Coal tar, coal tar creosote and oily wastes are often present as subsurface contaminants that may migrate below the water table, leaving a widely distributed residual source of contaminants leaching to the ground water. <i>In situ</i> chemical oxidation is a potentially viable technology for the remediation of aquifers contaminated with creosote and coal tars. The oxidant of choice would be flushed through the contaminated area to oxidize aqueous contaminants and enhance the mass transfer of contaminants from the oil phase. A series of batch and column experiments were performed to assess the ability of a chemical oxidizing reagent to oxidize creosote compounds and to increase mass transfer rates. Results from the column experiments were then simulated using a reactive transport model that considered 12 different creosote compounds undergoing dissolution, oxidation and advective-dispersive transport. Three strong chemical oxidizing reagents, Fenton's Reagent, potassium persulfate with ferrous ions, and potassium permanganate were tested with batch experiments to determine their reactivity towards creosote compounds. All three reagents successfully decomposed aqueous creosote compounds and were able to reduce the mass of the monitored creosote compounds within the oil phase. However, both the Fenton's and persulfate reagents required large molar ratios of iron and peroxide because the precipitation of iron continually removed the iron catalyst from the aqueous phase. Fenton's and persulfate reagents could be used in systems that are allowed to become acidic to solubilize the iron, but the cost of adjusting the pH, potential impact on aquifer geochemistry and the short lived free radical reaction make these reagents less practical than KMnO4. KMnO4 oxidizes a wide variety of creosote compound, can be used at very high concentrations, and its concentration will not be reduced significantly as it moves through the zone of contamination. The feasibility of using potassium permanganate as an oxidizing reagent for <i>in situ</i> treatment of creosote residuals was investigated using batch column experiments. Column experiments were conducted at a neutral pH in a carbonate rich sand matrix with creosote at 8 % saturation. The columns were treated intermittently with simulated ground water or KMnO4 dissolved in simulated ground water (8 g/L) for 172 days. Under these experimental conditions the KMnO4 decreased the initial mass of the monitored creosote compounds by 36. 5%, whereas in the control column (no oxidizer) only 3. 9% was removed. To remove all of the monitored creosote compounds from the columns it was calculated that the volume needed would be 40 times less for the KMnO4 solution, compared to flushing alone with simulated ground water. To evaluate the potential effectiveness of <i>in situ</i> chemical oxidation at field sites, numerical model simulations need to incorporate relevant chemical oxidation rates to assess system performance and to provide design guidance. In-depth kinetic studies were performed to determine rate constants and to gain insight into the oxidation of creosote compounds with KMnO4. The study examined the kinetics of the oxidative treatment of a selected group of creosote/coal tar compounds in water using excess potassium permanganate and investigated the correlation between reactivity and physical/chemical properties of the organic pollutants. The oxidation of naphthalene, phenanthrene, chrysene, pyrene, 1-methylnapthalene, 2-methylnaphthalene, acenaphthene, fluorene, carbazole, isopropylbenzene, ethylbenzene and methylbenzene closely followed first-order reaction kinetics, enabling calculation of second-order rate constants. Fluoranthene was only partially oxidized by permanganate and the oxidation of anthracene was too fast to be measured. Biphenyl, dibenzofuran, benzene and tert-butylbenzene failed to react in this study. Comprehensive column experiments complemented by numerical modeling revealed an unequal enhancement of the removal of creosote compounds from the oil phase. For the more readily oxidizable compounds such as pyrene and naphthalene, a significant increase in the mass transfer rates was observed in the oxidation columns, compared to the oxidant free column. For non-oxidizable compounds such as biphenyl and dibenzofuran, an increase in the rate of mass removal was also observed in the oxidation columns, even though their aqueous concentrations were not reduced in the column. This was due to the rapid removal of the more readily oxidizable compounds from the oil, which increases the mole fraction of the non-oxidizable compounds. Thus according to Raoult's Law, the concentration in the aqueous phase becomes closer to its pure phase liquid solubility and its aqueous concentration increases. The most significant result of the experiments is the observed increase in the rate of removal of those compounds that have low aqueous solubilities and are readily oxidized, such as pyrene and fluorene. Compounds that have low aqueous solubilities and are not readily oxidizable, such as chrysene, may still take a long period of time to be removed, but the removal time is greatly reduced with oxidation compared to flushing the area with water alone.