Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 288-293).

Thesis (M.E.)--University of Wisconsin--Madison, 1914. / Typescript. Includes index. eContent provider-neutral record in process. Description based on print version record.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains v, 46 p. : col. ill. Includes abstract. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:35:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-10-29Bitstream added on 2014-06-13T20:46:42Z : No. of bitstreams: 1 batista_jc_dr_guara.pdf: 2889755 bytes, checksum: 2777cd1f4225a0232c6281a5ca3d1e00 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho desenvolve um sistema para gerar energia elétrica com caldeira e turbina, para ocupar um nicho de mercado em que os sistemas a vapor existentes não são economicamente viáveis. O sistema utiliza a turbina Tesla que é compatível para essa faixa e não possui pás, podendo operar com vapor saturado fornecido por uma pequena caldeira consumindo lenha. A micro-geração proposta pode levar energia a milhões de brasileiros no campo, onde se dispõe de algum tipo de biomassa. Apesar do baixo custo da turbina Tesla, por ser de simples construção e compacta, e de suas incontáveis possibilidades de aplicação, se desconhece, até então, aplicações comerciais massivas devido ao baixo torque obtido nos protótipos feitos desde 1910 e por essa razão foi modificada. Este trabalho inova ao desenvolver um protótipo da turbina Tesla modificado para fornecer maior torque e ao comparar à turbina Tesla original. Devido à inexistência de equações que descrevem a turbina Tesla, um modelo matemático que permite projetar a turbina Tesla foi desenvolvido e validado por resultados experimentais e de simulação. Testes comparativos com duas turbinas com as mesmas dimensões mostraram que a turbina Tesla modificada apresentou eficiência superior à turbina Tesla original. Desenvolveu-se, também, um protótipo do sistema para micro-geração utilizando a turbina Tesla modificada, caldeira e gerador elétrico. Os custos do sistema e da energia gerada foram comparados com os de outros meios de geração mostrando serem competitivos economicamente para essa faixa de operação. / This work develops a system to generate electric power with boiler and turbine that aims to occupy the niche of the market for which steam systems are not economically viable. The system uses a Tesla turbine, which is compatible to the range of power. Also, it does not have blades, being able to operate with steam delivered by a small boiler fed with wood. The proposed micro-generation system can take energy to millions of Brazilians living in the country, where some type of biomass is available. In despite of the low cost of the Tesla turbine, because it is compact and simple to build, and despite of its uncountable possibilities of applications, massive commercial applications of the technology are not found due to the low torque of the prototypes built since 1910. For this reason, the Tesla turbine was modified. This work is original since it develops a modified Tesla turbine prototype to furnish a higher torque when compared to an original Tesla turbine. Due to the lack of equations that model a Tesla turbine, a mathematical model was developed to allow the design of the Tesla turbine; it was validated by means of experimental and simulating results. The comparative tests with two turbines, with same dimensions, showed that the modified Tesla turbine presents a higher efficiency than the original Tesla turbine. A micro-generation system, using the modified Tesla turbine, boiler and electric generator, was also developed. The costs of the system and of the generated energy were compared with other means of generation and showed to be commercially competitive for that range.

M.Ing. / In the highly competitive environment in which all companies have to operate, it is becoming more and more important to optimise the amount of time a piece of equipment is down for scheduled repairs and the scheduling of these repairs. In this dissertation the equipment that is considered are the seventeen Babcock Borsig designed boilers situated on the Sasol Secunda site. A schematic drawing of these boilers is shown in figure 1. This drawing does not include the Electrostatic Precipitator that is located at the outlet of the boiler. The main function of the seventeen boilers on the Secunda site is to supply process steam to the rest of the factory. With each of the plants that are supplied with process steam having its own needs at any point in time, ensuring that enough steam is available in the system becomes an extremely important issue. The reason for this is that the plants that are supplied with process steam form a train and if one of the plants can not produce to full capacity, the down stream plants are also affected. The secondary function of the boilers is to supply steam to ten turbines for the generation of electricity. This means that any steam that the factory is not using is used for the generation of electricity. The ten generators can not supply the full need of the factory and the rest is drawn in from the national electricity supplier. It is thus best to generate as much electricity as possible. With the price of electricity varying during the year, winter being more expensive, the time when a boiler is off becomes critical. To ensure that the necessary process steam is available the long term plan of the factory is used to calculate the year budget for steam required by the factory. But as with everything plans do change and a short term plan is used to ensure that enough process steam is available for the factory.

M.Tech. (Mechanical Engineering Technology) / This project researched the feasibility of using an existing mitre bend on the main condenser crossover ducting as an on-line flow measuring system. This flow measurement is based on the principle of an elbow type of flow meter. There are no detailed published standards or specifications available for Elbow flow meters. The knowledge of the cooling water flow rate through the individual condensers would allow turbine heat rate calculations to be performed. In addition condenser, cooling tower and cooling water pump performance can be evaluated. An on-line system would also highlight potential problems sooner, thus eliminating costly unplanned shutdowns. The majority of the straight length of condenser cooling water piping is under concrete, thus making access very difficult. The exposed condenser piping geometry is not ideal, with very distorted flow profiles expected, due to bends, valves, reducers, etc. Conventional flow measuring systems can therefore not be used, as ideal flow conditions (profiles) before and after the measuring instrument are required to er.sure the specified accuracy. The mitre bend being part of the piping geometry does not introduce additional head loss to the system and coupled to the low cost factor of an elbow type meter was the principal reason for the choice of this type of measuring system. Part of the innovative aspect of this research is that a conventional elbow is not used but an existing mitre bend is utilised as the fundamental flow measuring device. The Elbow/Bend differential pressure method to measure the condenser cooling water flow rate was investigated in the Flow laboratory at Eskom (Technology Research and Investigations). A geometrically similar mitre bend was purchased and installed onto the 700 mm NB pipeline at the laboratory. The diametrical differential pressure was measured at the 22.5° and 45°axes of the 0.8 D mitre bend. The differential pressure was related to the fluid flow rate, and a calibration constant C was determined. The velocity profiles under the test conditions were verified. A Computational Fluid Dynamics model of the laboratory mitre bend was also produced. The model provided a clearer understanding of the internal flow patterns and the exact pressures on the inside and outside of the bend. The tests that were conducted in the laboratory confirmed the suitability of converting the main condenser crossover ducting mitre bends into an on-line cooling water flow measuring systems.

Heat transfer characteristics associated with steam/air mixtures were studied in two pilot scale batch type steam/air retorts: a vertical positive flow retort and a horizontal forced circulation Lagarde retort. A method employing transient heat conduction into rectangular bricks of aluminum and stainless steel was developed to evaluate the surface heat transfer coefficient (h) of steam/air mixtures. A system was designed to facilitate an instantaneous drop of the test brick, from an insulated box inside the retort, into a specified steam/air medium after the come-up period. The influences of steam content, temperature, flow rate and flow direction of the heating medium and orientation of test bricks on the associated h values, temperature distribution and pressure stability in the retorts were studied. In addition, thermal processing efficacy was evaluated by measuring the rate of heat penetration into bricks of silicone rubber and rigid nylon which have thermal diffusivities in the range common for foods. In both retorts, steam content (S) of the mixture was found to be the major factor influencing h (p<0.05); however, temperature had no significant effect (p>0.05). Further, the flow direction and flow rate of the heating media in the positive flow retort, and brick orientation in the Lagarde retort also influenced h (p<0.05). The general relationship between h and S was exponential: h = a exp(bS). In the positive flow retort with the test brick in the vertical orientation, the values of a and b were 153 W/m²C and 0.0421 respectively, for steam/air media flowing in an upward direction, and were 337 W/m²C and 0.0355 respectively, for the media flowing downward. The surface heat transfer coefficient was also found to increase linearly with the medium flow rate. With the Lagarde retort, steam/air flow was always horizontal and flow rate was not adjustable. In this case, h was influenced by the test brick orientation. For bricks in the vertical orientation, the exponential parameters, a and b, were 1011 W/m²c and 0.0226 respectively, whereas in the horizontal orientation, these were 1669 W/m²C and 0.0132 Temperature distribution studies in the positive flow retort indicated that the overall standard deviation of the medium temperature at several locations during the cook period (excluding come-up) increased (p<0.05) with a decrease in the steam content and flow rate of the heating media. The effects of temperature and flow direction were nonsignificant (p>0.05). In the Lagarde retort, the temperature distribution was not influenced either by steam content or temperature of the steam/air medium. Pressure stability studies indicated that the air content and temperature of the medium increased (p<0.05) the standard deviations of retort pressure during the cook period. Based on the temperature and pressure deviations in the two retorts, steam/air mixtures with 86-90% steam contents were considered to provide satisfactory overriding air pressures for processing of retort pouches at 105-120°C. Heat penetration studies in the positive flow retort using nonpackaged test bricks of silicone rubber and nylon revealed an increase of up to 11% (p<0.05) in the heating rate index (f) of test bricks when the steam content of the media decreased from 100% to 50%. Heating of bricks at 120°C resulted in f values that were 5.5% larger (p<0.05) than those for bricks heated at 105°C. In the Lagarde retort, the effects of temperature and steam content of the media on f values were not significant. Heating bricks in the vertical orientation resulted in higher f values than in horizontal orientation in some tests, while a reverse trend was observed in others. The influence of entrapped air (15-30 mL per pouch) in retort pouches containing the bricks on f values was small when using a vertical rack that tightly constrained the bricks, whereas up to 260% higher values of f resulted when using an unconstraining horizontal rack while processing at 105-120°C in media of steam contents above 65%. These increases in f value could be prevented by using overriding air pressures of 70-100 kPa during the retort operation. The lag factor, j, was generally in the range of 0.5-1.0 for test bricks, with or without packaging, in the positive flow retort, and 0.8-1.1 in the Lagarde retort, when evaluated at 42% effectiveness for the come-up time. It was observed that in order for the j values to match the theoretical value of 1.27 for an infinite plate, the effectiveness was in the range of 60-90%. / Land and Food Systems, Faculty of / Graduate

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The demand for energy to sustain the economies of industrialized and developing nations has led to the search for alternatives to the use of imported petroleum fuels. Instability in the Middle Eastern countries, the major exporting sources for these petroleum feedstocks, has led to questions of availability in addition to the economic issues. While coal and nuclear technologies are currently the leading sources for reduction of petroleum imports, wood and other biomass feedstocks have garnered attention as to their potential as additional alternatives. Studies have shown that the amount of biomass waste resources in the United States, if converted effectively, could significantly reduce the need for petroleum imports. The focus of this research is to examine a patented, entrained flow, steam gasification process for the ability to produce gaseous components suitable for use as a fuel or in subsequent conversion processes, such as production of alcohol or diesel. The primary gases which are examined are hydrogen, carbon monoxide, carbon dioxide, and methane. The process is characterized using a nominal 3 ton (wood) per day “pre-pilot” facility and a nominal 30 ton (wood) per day “pilot” unit. Each of these gasification systems are characterized for production of primary gases using wood as the feedstock. As part of these characterizations, “equivalent” temperatures and residence times were developed that better described the process operations. An important consideration in the development of any industrial process is the ability to scale-up from a conceptual, or preliminary, scale to a size capable of commercial operation. As such, the characterizations of the two gasification systems were compared and relationships were developed to allow predictions of product gas compositions based on gasifier size as well as operating parameters.