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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comparative study of various technologies used for electricity generation

Ncwane, Mlungisi Vincent 25 March 2015 (has links)
M.Ing. (Mechanical Engineering) / Fossil fuels have been the backbone for the world in terms of fulfilling energy requirements. One of the best used types of fuel is the coal due to its availability throughout the globe. However, the coal resources cannot be reproduced hence the future generation may be negatively affected by the present method of generating energy. Unfortunately, these resources have undesirable effects to the environment which may lead to global warming. Other various sources may include oil and gas, nuclear, and the renewables. Oil and gas have diverse use currently especially in the transportation of goods and people across the continents. Nuclear energy is a mature technology but recent disasters have led to the public to be anti-nuclear. This perception is also fuelled by the in NGOs who are staunch supporters of renewable power. In addition, the issue about nuclear energy revolves around the undesirable side effect like the production of atomic bombs which are dangerous weapons ever. To produce nuclear energy, usually uranium is used which is also not available in abundance. Therefore, limiting their use will ensure that our future generations enjoy these benefits. Renewable sources like wind, wave, and solar, hydro, geothermal and tidal energies needs to be explored further for the sake of our future generations. The challenges which are faced by policy makers regarding the fossil fuels include catastrophic disasters which require billions of dollars in the form reconstruction after heavy drought and floods which damage the infrastructure and the economy at large. These disasters can be prevented if all governments are working together to eliminate or reduce the causes of climate change due to global warming. Unfortunately climate change must be addressed by all nations as it is no use for say one country to reduce emissions while others are not doing enough as we share the same atmosphere. The cost of renewable energy has been on the decline as the technology becomes more mature and the installed capacity across the globe increases. Thus more data is available to obtain understanding about the operations and maintenance of these systems. The other advantages of renewable sources are input costs are minimal for example wind energy comes from wind which is free. Same applies to solar energy which uses radiant energy from the sun which is also freely available. The coal and nuclear fuel power stations are currently in the forefront due to the fact that both stations may be used as based load to maintain grid stability in terms of power frequency. The renewable energy sources are very unreliable as they heavily dependent on weather. Unfortunately weather cannot be controlled.The renewable power is derived from biomass, geothermal, hydroelectric, solar, wave and wind. The renewable power tends to be the most expensive option in comparison to the traditional sources (coal, oil and gas, and nuclear). Technology for electricity generation from these renewable sources is now becoming mature and both maintenance and operating cost are decreasing. However, the costs of electricity from the traditional sources may further be increased by the cost of modifying the existing plants in order to comply with the new regulations which will then give renewable power a breakthrough. The renewable technologies appears to be winning the hearts and minds of those who care about environment and the future of the world at large as all sources of renewable are 100% recyclable.
2

Global and local controls upon the deposition of organic-rich Cretaceous sequences of western Venezuela : a geochemical study

Perez-Infante, Julio Vicente January 1996 (has links)
No description available.
3

Palynology and palynofacies of the Palaeocene of the Forties-Montrose Ridge Area, Central North Sea

Wood, Susan Elizabeth January 1992 (has links)
No description available.
4

A quantitative and kinetic study of hydrocarbon evolution during kerogen microscale pyrolysis

Scott, Andrew W. January 1994 (has links)
No description available.
5

The analysis of high molecular mass nitrogen compounds in fossil fuels

Wallace, S. January 1986 (has links)
No description available.
6

A PREFEASIBILITY STUDY OF INTEGRATING WOODROLL GASIFICATION TECHNOLOGY INTO OVAKO STEEL AND HEAB REPLACING FOSSIL FUELS IN HOFORS

Moner Lasheras, Alodia Baldesca January 2012 (has links)
Biomass gasification is considered a key technology in reaching targets for renewable energy and CO2 emissions reduction. This thesis studies the feasibility of a new technology of biomass gasification called WoodRoll for the production of Syngas with the aim to replace fossil fuels in the furnaces of the steel company OVAKO in Hofors.  This research attempts to study the techno-economic viability of WoodRoll technology integration with the district heating company HEAB, creating a synergy between the companies and WoodRoll technology. Moreover, a theoretically study of the environmental impact, concerning greenhouse effect and pollutants it is also carried out.   In the future scenario HEAB, as an energy supplier will be the gasification plant owner supplying with Syngas 5% cheaper than the fuels that they use today to Ovako.  Three different scenarios have been studied varying the capacity of the gasification plant. The scenarios are 5MW, 10MW and 15MW capacity.   The study show that the system is technically viable being possible to create a synergy  between the three process improving efficiency and decreasing cost and CO2 emissions.   The results from the economic study show that biomass gasification using WoodRoll technology is a highly interesting investment option for HEAB. From Ovako side, the project is very interesting too since the company can have a combustible 5% cheaper than the fuels used today without doing any investment. In 5MW scenario, 40GWh per year are converted in Ovako from oil to Syngas. With an investment for HEAB of 9.8 mSEK, profits were a Net Present Value of 6.3mSEK with 7.8 years of payback period. In 10MW scenario 80GWh were replaced. In this scenario, required investment was 146 mSEK with a NPV of 32.5 mSEK . Payback in this case was 6.3 years. The most profitable scenario was the case of 15M. With an investment of 188 mSEK the profits of the project were 60mSEK with a payback period of 5.8 years. In the three cases, especially in 15MW case, sensitivity study of the system show that it is very robust to changes in biomass cost and Syngas price. This parameters have a big impact on the profits but a big margin until becomes unfeasible.   From Ovako side, savings for the fuel conversion were 1.2; 2.4 and 3.6mSEK for the 5, 10 and 15MW respectively. Reduction of CO2 emissions was 11, 20 and 30 thousands of CO2 tons for the three scenarios allowing  the company to sell CO2 allowances and having an extra profit of 3, 6 and 8mSEK per year in the 5, 10 and 15MW scenario respectively.
7

The hydrodesulfurization of thiophene by Mo/Co treated oxyaluminum pillared montimorillonites /

Howard, Bret Harmon, January 1990 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 256-266). Also available via the Internet.
8

Urban air quality management and planning in South Africa

Scorgie, Yvonne 05 November 2012 (has links)
Ph.D. / Fossil fuel burning within residential, industrial and power generation sectors represents a persistent source of air pollution within many parts of South Africa, with the contribution of road transport emissions becoming increasingly important. Additionally, biomass burning, including agricultural burning and wild fires, represents an intermittent but seasonally significant source of atmospheric emissions. Effective air pollution control was historically hindered by the absence of enabling legislation and cooperative governance. The promulgation of the National Environmental Management: Air Quality Act, Act 39 of 2004 represented a major step forward in the evolution of air quality management within South Africa. The historical debate regarding the practicability of effective air quality management is however ongoing. South Africa‟s continued dependence on coal to support its energy-intensive industrial and mining sectors, continued household fuel burning for space heating and cooking purposes within a number of areas, and the dire need for employment creation and focus on rapid development continue to challenge the realisation of air quality improvements. This study investigates the multiple factors contributing to the degradation of air quality in South Africa, and the consequent human health, environmental and economic effects of this pollution. The study critically examines legal, technical and social measures implementable within a tailored system of air quality management which is compatible with socio-economic growth. This thesis integrates and expands on pertinent components of several individual research projects completed by the author during her tenure as a doctoral candidate. The research projects were completed during the period (2002 – 2009) on behalf of various parties including national and local government, standards setting bodies and private organisations. Quantification of health risks associated with significant anthropogenic sources within several South African conurbations, covering 40% of the national population, and the establishment of cost-optimised air pollution interventions, forms a key component of the thesis. In this externalities study, emissions were estimated and effects and associated costs quantified for household fuel burning, power generation, industrial and commercial fuel burning and road transport. Total direct health costs related to inhalation exposures to fuel burning emissions were estimated to be of the order of 3.5 billion 2002 Rands per annum across health effects, conurbations and source groupings assessed. Household fuel burning was estimated to be responsible for about 68% of the total health costs estimated across all conurbations, vehicle emissions for 13%, industrial and commercial fuel burning for 13%, and power generation for about 6%. Emission reduction opportunities were identified and assessed for residential fuel burning, coalfired power generation, road transport, coal-fired industrial boilers and specific individual industries. It was concluded that significant health effect reductions could cost-effectively be achieved through addressing residential fuel burning as a priority. Lower benefit-cost ratios associated with industrial and vehicular interventions are due, in part, to these fuel burning sources having been more effectively regulated historically. The need for effective management of industrial and vehicle emissions is however supported. Based on international experience and local trends in vehicle activity, the contribution of transport emissions will become increasingly ix significant if not adequately addressed. Industrial process emissions unrelated to fuel burning may include significant emissions of criteria pollutants, in addition to trace releases of a wide range of hazardous air pollutants. Internationally, actions taken to address air pollution problems have met with mixed results. Failure to integrate economic considerations into air quality management planning, and to integrate air quality considerations into development planning represent key weaknesses in the strategies implemented. A contribution is made in this thesis by highlighting such lessons and proposing legal, technical and social measures which, when implemented within a rational system of air quality management, are suited to addressing complex air pollution sources without negatively affecting socio-economic prosperity and equity. Components of an effective, affordable and equitable emissions control policy proposed for adoption within South Africa include phased national standards setting, compliance promotion and self-monitoring, market-based instruments, and the implementation of risk-based enforcement and compliance monitoring strategies.
9

Fossil fuel taxation for climate sustainability perspectives of mainstream and ecological economics applied to the case of South Korea /

Lee, Joon-Hee. January 2007 (has links)
Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Young-Doo Wang, School of Urban Affairs & Public Policy. Includes bibliographical references.
10

The effects of CO2 abatement policies on power system expansion

Fox, Conrad 31 August 2011 (has links)
Human development owes a great debt to cheap plentiful energy. Historically, abundant and energy dense materials such as coal, oil and more recently natural gas, have played an important role in powering our economies. To this day, any study analysing the short-term costs and benefits of energy system expansion, will continue to favour fossil fuels. At the same time, there is increasing concern about the levels of human made greenhouse gasses such as CO2 (the major by product of burning fossil fuels) and their forecasted effects on the global climate. This thesis investigates the consequences of using political intervention to internalize the cost of future negative effects of anthropogenic CO2 emissions. More specifically, this thesis investigates the effects of regulatory and market based instruments for curbing CO2 emissions from electric power systems in terms of both cost and efficacy. A model is developed to approximate the yearly changes in generation capacity and electricity supply mixture of a power system subject to the constraints of carbon abatement policies. The model proposes a novel approach for incorporating investment in non-dispatchable, intermittent wind generation capacity as a decision variable in the planning process. The model also investigates the effects of the stochastic nature of input parameters through the use of Monte Carlo simulation. To explore many features of this model, the Ontario power system is chosen for a case study because of its diverse portfolio of both generation technologies and political objectives. Five policies are simulated and compared with a ‘business-as-usual’ base case in which no carbon abatement policy is imposed. No single policy can meet all of the political objectives being investigated; however, some policies are clear winners in terms of specific objectives. Due to the broad scope of this work, the study finds many conclusions, such as: - Aggressive policies do not always promote heavy investment in intermittent wind generation sources. - On a $/tCO2 avoided basis, aggressive policies are expensive. Modest policies (very small penalties for CO2 emissions) are very sensitive to the uncertainties in future fuel prices and load profiles. - Investment in nuclear capacity is very responsive to the severity of CO2 penalty. The study also concludes that the most aggressive policies produce the greatest overall reductions in CO2 emissions. / Graduate

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