abstract: This study is a cultural history of danger, disaster, and steam-powered transportation in nineteenth-century America. The application of steam power to transportation, a globally transformative innovation, had particular influence in the early United States. A vast American continent with difficult terrain and poor infrastructure posed significant challenges, both to individual mobility and to a nation eager to build an integrated economy, a unified culture, and a functional republican government. Steamboats and locomotives offered an apparent solution, their speed and power seemingly shrinking distances between places and expanding mobility and access across space, a process contemporaries and scholars have described as a sort of space-time compression. However, these machines that overcame space also blew up, caught fire, wrecked, collided, derailed, and broke down, killing tens, and often hundreds, of Americans at a time. This dissertation analyzes the ways Americans encountered, interpreted, and adapted to these new dangers, all the while making the technology that created them an ever more essential aspect of their lives. I argue that Americans’ responses to disasters, filtered through the transportation and communication networks created by steam power, constituted a deep, shared reflection about the nature of expanded mobility in a fast-evolving modern America. Though few suffered disaster directly, Americans collectively framed the danger of steam as both a profound national problem and an evocative symbol of modernity. Through public conversations mediated by print, Americans identified susceptibility to danger as inherent to high-speed travel, and, alongside practical safety measures, developed distinctly modern cultural adaptations to understand and manage that danger. By century's end, Americans had cultivated a modern mentality on mobility, technology, and danger: though most Americans never experienced disaster they were intimately aware of it, and though familiar with catastrophe they understood it as unlikely and accepted it as a feature of their modern technological lives. / Dissertation/Thesis / Doctoral Dissertation History 2016

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Este trabalho apresenta o estudo da dinâmica de uma instalação propulsora a vapor através da técnica da modelagem e simulação. O modelo matemático é obtido das Leis da Termodinâmica e dos conceitos básicos da mecânica dos fluídos e transferência de calor, e a simulação é efetuada em um computador digital. Inicialmente cada componente do ciclo é modelado individualmente, determinando-se as suas variáveis de estado, de entrada e de saída. A seguir o modelo é simulado para analisar a influência dos diversos parâmetros nas respostas do elemento. O modelo matemático da instalação propulsora a vapor é obtido agrupando-se convenientemente os modelos dos vários componentes do ciclo. Com isso obtêm-se um sistema de 47ª ordem que pode simular diversos casos de interesse real. Neste trabalho são analisadas as respostas do ciclo para dois casos. A primeira corresponde ao fechamento parcial da válvula de controle da turbina e a segunda ao corte na vazão de óleo combustível. / This paper presents a study of the dynamics of a steam power plant using techniques of modelling and simulation. The mathematical model derives form the laws of Thermodynamics and basic concepts of fluid mechanics and heat transfer; the simulation is carried out in a digital computer. Each component is first modelled individually, and its state, input and output variables are determined. The model is then simulated for the analysis of the influence of the various parameters in the responses of the component. The mathematical model of the complete power plant is constructed by the convenient grouping of the various component models of the cycle. Thereby a 47th order system is obtained, which can simulate various cases of interest. The cycle\'s response for two cases are analysed. The first case correspond to the partial closing of the turbine control valve and the second to the fuel flow interruption .

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No presente trabalho foi estudado o efeito da adição de cálcio, bário e estrôncio (0%-5% em massa) em catalisadores Ni/Al2O3, contendo 5% de níquel em massa, frente à reação de reforma a vapor do etanol com o objetivo de inibir a reação de desidratação do etanol, precursor do carbono. Os catalisadores foram preparados por dois métodos: impregnação (I) e co-precipitação (C). Inicialmente todos os catalisadores obtidos foram submetidos a analise de espectroscopia dispersiva em emissão de raios X (EDX), para confirmação de suas composições químicas, em seguida foram aplicados na reação de reforma a vapor do etanol, dentre os catalisadores estudados os que apresentaram a menor formação de eteno foram, 5%Ca-5%Ni/Al (I) e 5%Ca-5%Ni/Al (C) dentre os que continham cálcio; 0,5%Ba-5%Ni/Al (I) e 5%Ba-5%Ni/Al (C) dentre os que continham bário e 5%Sr-5%Ni/Al (I) e 5%Sr-5%Ni/Al (C) dentre os que continham estrôncio, sendo então submetidos as etapas de caracterização, difração de raios X (DRX), redução a temperatura programada (RTP), área superficial específica pelo método BET e reação de decomposição do isopropanol. O desempenho destes catalisadores foi comparado com o obtido para os catalisadores sem aditivos 5Ni/Al(I) e 5Ni/Al(C). O método da impregnação demonstrou ser mais eficiente do que o método da co-precipitação para o alcance dos objetivos do trabalho e o catalisador 5Ca-5Ni/Al (I) foi o mais efetivo na redução da acidez da alumina e consequentemente mostrou menor deposição de carbono. / Catalysts of Ni/Al2O3 containing 5wt% of nickel and modified by calcium, barium and strontium addition (0wt% - 5wt%) were tested in the ethanol steam reforming with the goal of reduce the reaction of dehydratation of ethanol, a carbon precursor. The catalysts were prepared by two methods: impregnation (I) and co-precipitation (C). Initially, all catalysts were subjected to analysis by Energy-dispersive X-ray spectroscopy (EDX), to confirm their chemical compositions, then they were applied in the steam reforming of ethanol, Among the catalysts studied those with lower ethene production were: 5%Ca-5%Ni/Al (I), 5%Ca-5%Ni/Al (C) among those containing calcium; 0,5%Ba-5%Ni/Al (I), 5%Ba-5%Ni/Al (C) among those containing barium and 5%Sr-5%Ni/Al (I), 5%Sr-5%Ni/Al (C) among those containing strontium, being submitted to the characterization by X-ray diffraction (XRD), temperature programmed reduction (TPR), specific surface area by BET method and reaction of isopropanol decomposition. The performance of these catalysts was compared to with the catalysts without additives 5(wt%)Ni/Al(I) and 5(wt%)Ni/Al(C). The impregnation method was more effective than the method co-precipitation for achieving the objectives of this work and the catalyst 5Ni-5Ca/Al (I) was the more effective in the reduction of alumina acidity and also showed the lower carbon deposition.

Catalisadores de Ni suportado em La2O3, SiO2 e La2O3-SiO2 (com teores mássicos de La2O30 de 10%, 30% e 50%) tiveram seu desempenho avaliado frente a reação de reforma a vapor de glicerol. O efeito do suporte sobre a atividade, estabilidade e seletividade do catalisador foi avaliado, assim como diferentes métodos de preparo, teores de Ni e temperaturas de reação. Os catalisadores foram preparados pelos métodos da impregnação úmida seqüencial, impregnação úmida simultânea, impregnação sobre o suporte precipitado e co-precipitação, utilizando teores mássicos de 5%, 10% e 15% de Ni. Foram utilizadas as seguintes técnicas de caracterização: espectroscopia de energia dispersiva de raios X, fisissorção de nitrogênio, difratometria de raios X, redução a temperatura programada e difração de raios X in situ. Os catalisadores foram testados por um período de 5h, a fim de verificar a atividade e seletividade para a reação de reforma a vapor de glicerol a 500°C, 600°C e 700°C, e as propriedades dos catalisadores foram correlacionadas com os resultados obtidos dos ensaios catalíticos. Após as reações, os catalisadores foram submetidos as seguintes análises: análise elementar, difratometria de raios X e microscopia eletrônica de varredura. Foi observado que o Ni interage de forma variada com os diferentes suportes, que o método de preparação utilizado influencia propriedades dos catalisadores e que, dependendo do teor mássico de Ni suportado, o catalisador pode ser mais ou menos ativo para a reação de reforma a vapor de glicerol. Observou-se também que a temperatura influencia no desempenho da reação, sendo que os melhores resultados foram obtidos a 600°C com o catalisador 15Ni30LaSi preparado por impregnação úmida simultânea, que foi testado também por 20h para que fosse analisada sua estabilidade em um maior intervalo de tempo. / Ni catalysts supported on La2O3, SiO2 and La2O3-SiO2 (with 10%, 30% and 50%wt.La2O3) were evaluated in the glycerol steam reforming reaction. The effect of the supports was analyzed on the catalysts activity; stability and selectivity as well as different methods of preparation, Ni contents and reaction temperatures. Catalysts were prepared by the sequential wet impregnation, simultaneous wet impregnation, impregnation of Ni on support precipitate and co-precipitation methods using 5%, 10% and 15%wt.Ni. The catalysts were characterized by energy dispersive X-ray spectroscopy, nitrogen physisorption, X-ray diffraction, temperature programmed reduction and X-ray diffraction in situ. The catalytic tests were performed during 5 hours in order to verify the activity and selectivity for the glycerol steam reforming at 500°C, 600°C and 700°C, and identify the relationship between the catalysts properties and the results obtained with the catalytic tests. After the reactions, the catalysts were characterized by elemental analysis, X-ray diffraction and scanning electron microscopy. It was observed that the Ni interacted variously with different supports; the preparation method used influenced on the catalysts properties and, depending on the Ni content, the catalyst was more or less active for the glycerol steam reforming. It was also observed that the temperature of reaction influenced on the reaction performance, and the best results were obtained at 600°C with the 15Ni30LaSi catalyst, prepared by simultaneous wet impregnation, which was also tested for 20 hours to analyze its stability in a longer period.

A high demand of both electricity and heat exists in Arizona Chemical (a chemical plant dedicated to the distillation of Crude Tall Oil) for production processes. Due to the rising cost of resources and electricity, more and more companies are trying to decrease the energy expenses to increase their competitiveness in a global market, thus increasing their profit. Some companies look at their energy consumption in order to diminish it or to explore the opportunity to generate their own and cheaper energy. In companies where the production of steam already takes place, cogeneration can be a good solution to palliate the cost of the energy used. This study addresses this issue through three actions such as the characterization of the boiler, a better steam flow measurement grid and the generation of electricity. The first one addresses the state of one of the key parts of steam production, the boiler, through the calculation of its efficiency with two different methods (direct and indirect calculation). These methods require some measurements which were provided afterwards by the company supervisor. This will allow the company to identify the weaknesses of the boiler to be able to improve it in the future. The second one aims to improve the knowledge about the steam system. New flow measurement points were suggested after doing an analysis of the current controlled flows to have a better overview outline of the steam use.The third one studies the generation of electricity with a Rankine cycle. The limitations in the characteristics of the steam were identified and different configurations are proposed in accordance to the restrictions identified. An efficiency of 93% is obtained for the boiler with the direct method and 82.3 % for the indirect one. The difference between them can be explained by the use of datafrom different time frames for both methods. The main contributors to the losses are the ones related to the dry flue gas and the hydrogen in the fuel. In the current status only 40% of the steam flows are identified, a number which is expected to raise with the new measurement points. It was not possible to estimate the effect of the new points due to the desire of the company to not disturb the current production. Due to the fuel price the production of steam for only electricity was not profitable and instead the generation of both electricity and heat from the same steam is proposed. This integrated system is now possible to implement due to its low payback time (2.3 years). This solution can generate 758 kW of electricity and provide the company with 6437 MWh of electricity each year. Then, the effect of the variation of different variables over the performance of the cycle were studied: different electricity prices, steam rate production, fuel cost and the state of the condensate recovery were discussed. The variation of both the condensate recovery and fuel cost did not affect the payback time due to their costs being neutralised by the revenues obtained from them. The variation of the electricity prices and steam production affects the payback but due to the high revenue that is expected it does not hamper the good nature of the investment. The generation of electricity is recommended due to the low payback time obtained. The different variations studied in the system did not change the payback time notably and showed that the investment is highly profitable in all the scenarios considered. The use of two smaller turbines instead of the one chosen (with a maximum rated power of 6 MW while only 758 kW is generated with the proposed solution) should be studied since the turbines would work closer to their maximum efficiency.

M.Tech. (Mechanical Engineering) / Eskom fossil fuel power stations operate under various conditions and the ageing fleet of fossil fuel power stations are under strain due to the rising demand in electricity. The quest for cheaper electricity in growing businesses and bringing foreign investment into South Africa is significant for economic growth. Therefore, minimizing operation costs and improving availability, reliability and thermal heat rate are key objectives for the operation of the business. Thermal heat rate calculation is a method used to assess the performance of fossil fuel power stations. It provides an indication of the thermal performance which reflects the condition and operation of the plant. This dissertation refers to the tools used to measure the condenser performance and to identify the reason for unhealthy condenser performance and an increase in thermal heat rate. Problem: Poor condenser performance causes significant losses in generation and thermal heat rate in fossil fuel plants. Loss in generation and thermal heat rate is caused by condenser backpressure. This has an adverse effect on turbine thermal heat rate and henceturbine efficiency. The performance of the condenser affects the turbine performance to a large extent. Decreased condenser performance will increase the turbine thermal heat rate, i.e. kJ/kWh, because of the increased steam consumption per kWh of energy generated and therefore lowering the overall turbine efficiency. This will result in poor thermal heat rate efficiency resulting in an increased coal burn rate, i.e. kg/kWh, and an increased fuel bill and carbon foot print for the fossil fuel power station. The aim of this dissertation is to determine the effects of condenser performance on thermal heat rate and to provide the engineering and operating personnel with a guide for monitoring condenser back pressure in order to improve turbine thermal heat rate and turbine efficiency. Method and Procedure: Chapter 4 describes the method and procedure used for the pre and post outage evaluation to cost-effectively determine the current condition of the condenser and to quantify the increase in thermal heat rate due to condenser degradation. The pre and post outage evaluation offered an opportunity to evaluate and quantify the effectiveness of the maintenance program and the value of the capital layout undertaken during the scheduled Unit outage. Findings: Chapter 5 discusses the findings of the pre and post outage data analysis of the condenser using the EtaPRO system as the tool. Re-tubing 50% of the condenser inner loop tubes and cleaning the other 50% of the outer loop tubes demonstrated a decrease in condenser backpressure and therefore an improvement in thermal heat rate. This will also result in an improvement in turbine cycle efficiency and reduce coal cost.

Please read the abstract in the section front of this document / Dissertation (MEng(Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / unrestricted

Production in Canada’s oil sands has been increasing, with a projected rate of 4.5 million barrels per day by 2025. Two production techniques are currently used, mining and in-situ, with the latter projected to constitute ~57% of all production by that time. Although in-situ extraction methods such as Steam Assisted Gravity Drainage (SAGD) are less invasive than mining, they result in more greenhouse gas (GHG) emissions per barrel and require large amounts of water that must be treated and recycled with a make-up water requirement of about 10%. CanmetENERGY is developing a steam generation technology called the High Pressure Oxy-fired Direct Contact Steam Generator (HiPrOx/DCSG, or DCSG for short) that will reduce these water requirements and sequester GHGs. This study evaluates the technical feasibility of this technology using process simulations, bench-scale testing, and pilot-scale testing. At first, a method in which to integrate the DCSG into the SAGD process was presented and process modeling of expected system performance was undertaken. The process simulations indicated that DCSG decreased the energy intensity of SAGD by up to 7.6% compared to the base SAGD case without carbon capture and storage (CCS), and up to 12.0% compared to the base SAGD case with CCS. Bench-scale testing was then performed using a pressurized thermogravimetric analyzer (PTGA) in order to investigate the effects of increased pressure and high moisture environments on a Canadian lignite coal char’s reactivity. It was found that under reaction kinetic-controlled conditions at atmospheric pressure, the increased addition of steam led to a reduction in burning time. The findings may have resulted from the lower heat capacity and higher thermal conductivity of steam compared to CO2. At increased pressures, CO2 inhibited burnout due to its higher heat capacity, lower thermal conductivity, and its effect on C(O) concentrations on the particle surface. When steam was added, the inhibiting effects of CO2 were counteracted, resulting in burnout rates similar to pressurized O2/N2 environments. These preliminary results suggested that the technology was feasible at a bench-scale level. Conflicting literature between bench-scale and pilot-scale studies indicated that pilot-scale testing would be advantageous as a next step. At the pilot-scale, testing was performed using n-butanol, graphite slurry, and n-butanol/graphite slurry mixtures covering lower and upper ends in fuel reactivity. It was found that stable combustion was attainable, with high conversion efficiencies in all cases. With the n-butanol, it was possible to achieve low excess oxygen requirements, which minimizes corrosion issues and reduce energy requirements associated with oxygen generation. With graphite slurry, it was found that it was possible to sustain combustion in these high moisture environments and that high conversion was achieved as indicated by the undetectable levels of carbonaceous materials observed in downstream equipment. Overall, these studies indicate that DCSG is technically feasible from the perspectives of energy and combustion efficiencies as well as from a steam generation point of view. Future work includes the investigation of possible corrosion associated with the product gas, the effect of CO2 on bitumen production, the nature of the mineral melt formed by the deposition of the dissolved and suspended solids from the water in the combustor, and possible scaling issues in the steam generator and piping associated with mineral deposits from the dissolved and suspended solids in the produced water is recommended.