M.Sc. / Worldwide, coal is one of the major sources of energy. In 1999 it was estimated that the global electricity generation from coal was about 36% of the total world electricity production (Knapp, 1999:11). With the combustion of coal for electricity generation however, negative environmental impacts occur. These are mainly caused by carbon dioxide, nitrous oxides, sulphur dioxide and particulate matter emissions. With an ever-growing global population, the need and demand for electricity is increasing. These needs and demands need to be addressed in an economically, socially and environmentally acceptable manner. In this study the author examines, analyses and compares the emissions from coalfired power stations in South Africa, Australia, Canada, Germany, India and the United States of America over a chosen period of time (1995-2001). The results of the study indicate, that, within the comparative group, South Africa is not the greatest producer of emissions from coal-fired power stations. It is the fourth biggest emitter of CO2. It has the highest SO2 emissions, because of the low-grade coal burned in the power stations that have been specifically designed to burn this type of coal. It is the second biggest emitter of NOx, and the third biggest emitter of particulates. Germany is the country that has shown the greatest progress in emissions reductions. This has been the result of restructuring and economic incentives. Overall, South Africa can be ranked third, on par with Australia.

Analysis of future alternatives for US utilities is needed as a part of evaluating the impact of combined cycle and phased-construction of integrated coal gasifier power plants on generation expansion. The study encompassed both large and small electric utilities and long-run, least-cost expansion plan for the generating system and studies of the short-run production cost of electrical generation for selected years. The long-run studies were carried out using the Wien Automatic System Planning Package (WASP-II). The optimal combined cycle penetration level was determined for a set of assumptions that involve economics, new technology trends, and feasibility as well as the utility's existing capacity and load forecast. Additional cases were run to account for phased construction and coal gasification. Two electric utilities were selected in this study. These are a U.S. southeastern utility the Bangladesh Electric Utility. The former was chosen as the large utility. The latter was considered a small size utility. WASP-II enhancements enabled us to run cases using IBM-RT and to account for phased construction. The sensitivity studies involved the penetration levels, the fuel supply (oil and natural gas), and economic dispatch of coal gasifiers in particular, and combined cycle power plants in general. Load forecast, and availability of hydroelectric energy were kept uniform. However, adding new power plants and retiring old ones were considered to achieve a more economical and reliable planning strategy while considering issues of technical feasibility. / M.S.

Lichens have been used extensively and with considerable success as bioindicators of atmospheric pollution in North America and Europe for more than thirty years. Little research has followed in tropical and subtropical regions where population growth is rapid and environmental pressures unprecedented. However, taxa used as bioindicators in other studies and/or taxa having this potential, occur naturally in Central Florida. A new potential major source of pollution, the coal-fired Curtis H. Stanton Energy Center, is about to begin operation providing the opportunity to determine the extent of impact. Therefore, lichen monitoring sites have been established and the collection of baseline data reflecting species diversity, frequency, overall cover and vitality has been accomplished. These locations will be preserved for future monitoring activities. Voucher specimens and photographic documentation of sample populations have been deposited in the herbarium of the University of Central Florida.

Energy developments in the Southwest have established a basis for the examination of complexities involved in environmental decision making. The coalfired generation facilities exhibit an impact potential on the social, physical, and economic surroundings of both local and distant communities. A recent seventeen-volume report directed by the U.S. Department of Interior, The Southwest Energy Study, is an indicator of the magnitude of the situation. The Four Corners Program is a team research project with emphasis placed upon technology transfer. Simulation models are used to estimate the physical, economic, and social effects of a range of decisions concerning alternate power schedules. The research results are communicated to interest groups in other than the usual report form. A workshop environment allows the participants to interact with the decisions, the models, the results, and one another. One of the simulation models is the groundwater model. The groundwater model is used to estimate head declines in the confined and unconfined portions of the Navajo Sandstone and the Mesaverde Formation on Black Mesa. The Mesaverde Formation is found to be isolated from the Navajo Sandstone by the Mancos Shale and other intervening layers. A simulation routine developed by the Illinois State Water Survey is modified and adapted to the problem. As a result of the small amount of published aquifer data, minimum or below minimum values of aquifer properties and a sensitivity analysis were incorporated into model considerations. Pumping rates and pumping durations of groundwater for slurry transfer of coal define the decision space. The mining pumpage will have a negligible effect upon the Indian wells located in recharge areas of the Navajo Sandstone. The effects of mining pumpage upon potentiometric surfaces in the artesian portion of the Navajo Sandstone will range from zero to twenty percent of the artesian head, depending upon location and aquifer properties. Theoretical effects of groundwater pumpage on four monitor locations are quantified in terms of ranges of variation. These results can help to evaluate development plans for decision makers and other interest groups. With the future acquisition of measured drawdowns, consideration of theoretical and actual results can provide additional precision to aquifer parameter estimates. The Four Corners Program has a two year duration. The goal of the first year effort was the completion of simulation modeling. Beyond technical or prejudicial hurdles, the workshop encounters will require a public relations and communications posture which is conducive to group participation. The effectiveness of simulation as a means of technology transfer to a variety of users is yet to be evaluated.

Run-of-mine (ROM) coal sampling is one of the most important factors in determining the disposition of ROM coal for an overall emission control strategy. Determination of the amount of sample, or still better, the frequency of ROM coal sampling is thus essential to the analysis of overall emission control strategies. A simulation model of a portion of the Upper Freeport coal seam in western Pennsylvania was developed employing conditional simulation. On the simulated deposit, different mining methods were simulated to generate ROM coal data. ROM coal data was statistically analyzed to determine the sampling frequency. Two schemes were suggested: (1) the use of geostatistical techniques if there is spatial correlation in ROM coal quality, and (2) the use of classical statistics if the spatial correlation in ROM coal quality is not present. Conditions under which spatial correlation in ROM coal quality can be expected are also examined. To link the ROM coal and coals from other sources to coal stockpiles and subsequently to solve coal blending problems, where varying qualities of stockpiled coals are normally used, an interactive computer program was developed. Simple file-handling, for stockpiling problems, and multi-objective goal programming technique, for blending problems, provided their solutions. The computer program was made suitable for use on both minicomputer and microcomputer. Menu-driven and interactive capabilities give this program a high level of flexibility that is needed to analyze and solve stockpiling and blending problems at the power plant.

No description available.

A dissertation submitted to the faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science in Engineering. 21 November 2016 / In this work a comprehensive exergy analysis and heat integration study was carried out on a coal based oxy-combustion power plant simulated using ASPEN plus. This is an extension on the work of Fu and Gundersen (2013). Several of the assumptions made in their work have been relaxed here. Their impact was found to be negligible with the results here matching closely with those in the original work. The thermal efficiency penalty was found to be 9.24% whilst that in the original work was 9.4%. The theoretical minimum efficiency penalty was determined to be 3% whilst that in the original work was 3.4%. Integrating the compression processes and the steam cycle was determined to have the potential to increase net thermal efficiency by 0.679%. This was close to the 0.72% potential reported in the original work for the same action. / MT2017

Geological carbon sequestration, as a method of atmospheric greenhouse gas reduction, is at the technological forefront of the climate change movement. During sequestration, carbon dioxide (CO���) gas effluent is captured from coal fired power plants and is injected into a storage saline aquifer or depleted oil reservoir. In an effort to fully understand and optimize CO��� trapping efficiency, the capillary trapping mechanisms that immobilize subsurface CO��� were analyzed at the pore-scale. Pairs of proxy fluids representing the range of in situ supercritical CO��� and brine conditions were used during experimentation. The two fluids (identified as wetting and non-wetting) were imbibed and drained from a flow cell apparatus containing a sintered glass bead column. Experimental and fluid parameters, such as interfacial tension, fluid viscosities and flow rate, were altered to characterize their relative impact on capillary trapping. Computed x-ray microtomography (CMT) was used to identify immobilized CO��� (non-wetting fluid) volumes after imbibition and drainage events. CMT analyzed data suggests that capillary behavior in glass bead systems do not follow the same trends as in consolidated natural material systems. An analysis of the disconnected phases in both the initial and final flood events indicate that the final (residual) amount of trapped non-wetting phase has a strong linear dependence on the original amount of non-wetting phase (after primary imbibition), which corresponds to the amount of gas or oil present in the formation prior to CO��� injection. More importantly, the residual trapped gas was also observed to increase with increasing non-wetting fluid phase viscosity. This suggests that CO��� sequestration can be optimized in two ways: through characterization of the trapped fluid present in the formation prior to injection and through alterations to the viscosity of supercritical CO2. / Graduation date: 2013

Originally presented as the author's Thesis--Technische Hochschule Aachen, 2008. / Includes bibliographical references.

Thesis (M.S. in E.A.S.)--School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 2004. Directed by Philip N. Froelich. / Includes bibliographical references (leaves 131-133).