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.

No / To obtain accurate results in the RHX dating of ceramics, it is essential that the RHX measurements are continued until the rate of mass gain is constant with (time)1/4. In this paper, we discuss how the initial stages of mass gain are affected by the specific surface area (SSA) of the ceramic material. The paper provides guidance on experimental protocols to avoid dating results being distorted by relatively early-time mass gain data.

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.

Eighteen stands of bur oak (Quercus macrocarpa Michx.) and trembling aspen (Populus tremuloides Michx.) were sampled and analyzed using dendrochronological methods to study the potential effects on tree growth of emissions from a 132 MW coal-fired generating station. Sixteen stands were sampled within a 16-km radius of the station, and two control stands were sampled outside of the range of influence, at distances . 40 km. All stands showed similar radial growth patterns from 1960-2001, regardless of distance from or direction relative to the generating station, and a number of stands, including the controls, had below average growth after 1970. Both species were significantly affected by climatic factors, showing decreased radial growth with increasing June temperature. The species differed in their growth responses to spring precipitation and temperature in the previous October. One bur oak site displayed marked radial growth decline beginning in the mid-1970s, strongly pronounced following 1977. This decline does not appear to be related to emissions from the station, but is suspected to be a result of poor site conditions (shallow soil developed over calcareous till), confounded by a change in drainage (a road was built adjacent to the stand in 1977, perpendicular to the direction of drainage). The below average growth seen in 1970-2001 across most stands is likely attributable to stand dynamics and age effects.

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The first detailed systematic investigation of a cement plant with various carbon capture technologies has been performed. The calcium looping (Ca-looping) process has emerged as a leading option for this purpose, since this process applied to a cement plant provides an opportunity to use the CaO purge for clinker production. The Ca-looping process is comprised of two interconnected reactors where the carbonator captures CO2 from flue gases and the calciner regenerates the CaCO3 into CaO by oxy-combustion. Fully integrated process flowsheets have been developed and simulated in UniSim Design Suite from Honeywell. The detailed carbonator model has been implemented using Matlab and incorporated into UniSim to provide a full flowsheet simulation for an exemplary dry-feed cement plant as a user-defined operation. The base cement plant simulation was also modified to integrate three different carbon capture processes: membrane; indirect calcination; and amine-scrubbing. Furthermore, an advanced configuration of Ca-looping process has been investigated where the energy intensive air separation unit was replaced with a chemical looping combustion (CLC) cycle. Each case has been optimised to minimise its energy consumption and compared in terms of levelised cost of cement and its resulting cost of CO2 avoided at the same CO2 avoidance rate. The proposed integration of the Ca-looping process is capable of achieving over 90% CO2 avoidance with additional fuel consumption of 2.5 to 3.0 GJth/ton CO2 avoided. By using an advanced configuration of the Ca-looping process with a CLC cycle, the additional fuel consumption can be reduced to 1.7 GJth/ton CO2 avoided, but the cost of the oxygen carrier is the major concern for this system. Among the other CO2 capture options, the membrane process is a promising alternative for the Ca-looping process since it has a potential of achieving the target CO2 avoidance rate and purity requiring lower energy consumption. The indirect calcination process provides moderate levels of CO2 avoidance (up to 56%) without a need of an external capture process whereas the integration of the amine process in a cement plant is challenging as a result of the requirement of steam for solvent regeneration. Furthermore, considering zero net CO2 emissions associated with biomass combustion systems, a novel concept has been analysed to capture of CO2 in-situ with the Ca-looping process while operating the combustor of a dedicated biomass power plant at sufficiently low temperature. This process is capable of achieving 84% overall CO2 capture rate with an energy penalty of 5.2% when a proper heat exchanger network is designed with the support of a pinch analysis. The techno-economic performance of the biomass power plant with in-situ Ca-looping CO2 capture process was compared with that of the alternative biomass-air-fired and biomass-oxy-fired power plants.