Made available in DSpace on 2014-06-11T19:35:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T20:26:38Z : No. of bitstreams: 1 holanda_mr_dr_guara.pdf: 2661170 bytes, checksum: db439d75620f679e10a9258dd795b0ad (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A cogeração tem sido proposta em diferentes oportunidades para a solução de problemas de atendimento das necessidades energéticas de empresas (ou grupos de empresas em pólos industriais) a partir de combustíveis fósseis e biomassas vegetais, de forma preponderante. Há, contudo, uma forte demanda mundial para que sejam desenvolvidas novas alternativas de geração, bem como fontes energéticas, dentre as quais se destaca o lixo urbano, na medida em que esse colabora fortemente com a ocupação de áreas economicamente rentáveis, bem como com problemas de ordem social e ambiental quando não devidamente gerenciado. Esta Tese tem por objetivo analisar as perspectivas da geração combinada de eletricidade e vapor em pólos industriais a partir da destruição de resíduos sólidos municipais; para tanto, desenvolve-se uma avaliação das principais formas de deposição do lixo urbano, bem como da cogeração em termos dos sistemas empregados. Foi analisada a legislação ambiental de diversos países, com especial destaque para a política ambiental brasileira, de modo a que fossem observadas as diretrizes de emissões preconizadas em nível mundial e de forma comparativa. Neste item, concluiu-se pela adequada formulação apresentada pela legislação brasileira, que contempla os principais limites de qualidade do ar e de emissão em níveis compatíveis com os que vêm sendo praticados internacionalmente. De modo a subsidiar a modelagem apresentada no corpo da Tese, foi desenvolvido um levantamento acerca das características operacionais e de investimento das principais tecnologias de remoção de poluentes atmosféricos, bem como formas alternativas para “produção limpa” de energia. Para que pudesse ser desenvolvida uma formulação de base exergoeconômica e ambiental para o presente estudo, foi realizada uma revisão bibliografia acerca... . / working out problems concerning energetic needs of enterprises (or groups of enterprises in industrial stocks) preponderantly from fossil fuels and vegetable biomasses. There is, however, a strong world demand for new generating alternatives, as well as energetic sources, be developed: among them it can be pointed out urban waste, while it contributes strongly for the occupation of economically profitable areas and environmental and with not properly managed social problems. This Thesis aims to analyse the perspectives of electricity and steam combined generation industrial stocks from municipal solid waste destruction; therefore, an evaluation of the main forms of urban waste deposition, as well as the cogeneration in terms of the system used is developed. The environmental legislation for a number of countries, with special emphasis for the Brazilian environmental policy, was analysed , so that the emission guidances preconized at a world summit level and at a comparative level could be observed. In this item, the decision was made for the Brazilian legislation, that contemplates the principal air and emission quality limits at levels consistent with the ones worldwide used. In order to subsidize the modeling presented in this Thesis, a gathering of facts on the operational and investment characteristics of the chief technologies for removing atmospheric pollutants, as well as alternate forms for “clean production” of energy was developed. It was performed a bibliographic revision on the principal models used for the calculation of environmental costs, to allow the development of a formulation on environmental and exergoeconomic basis for the present study, as well as alternative models which, yet not showing environmental utilization, could, that way, be considered with small modifications. For the analysis of cogeneration with municipal solid... (Complete abstract, click electronic address below).

This thesis encompasses CO2 mitigation using three different processes: i) natural gas-fired combined cycle with chemical looping combustion (CLC), ii) trigeneration of electrical power, hydrogen and district heating with extended CLC, iii) steam-based gasification of biomass integrated in an advanced power cycle. In CLC, a solid oxygen carrier circulates between two fluidised-bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In this thesis, CLC has been studied as an alternative process for CO2 capture in a natural gas-fired combined cycle (NGCC). The potential efficiency of such a process using a turbine inlet temperature of 1200 °C and a pressure ratio of 13 is between 52 and 53 % when including the penalty for CO2 compression to 110 bar. It is shown that this efficiency cannot be further improved by including an additional CO2 turbine. Two conceivable reactor designs for CLC in an NGCC are presented. Top-firing has been studied as an option to overcome a temperature limitation in the CLC reactor system. The degree of CO2 capture is shown versus the temperature in the CLC reactor and its combustion efficiency. CLC has the potential to reach both a higher efficiency and a higher degree of CO2 capture than conventional post combustion CO2 capture technique. However, further research is needed to solve technical problems as, for example, temperature limitations in the reactor to reach this potential. Extended CLC (exCLC) is introduced, in which hydrogen is not only produced but also inherently purified. The potential efficiency of a novel tri-generation process for hydrogen, electricity and district heating using exCLC for CO2 capture is investigated. The results show that a thermal efficiency of about 54% might be achieved. A novel power process named evaporative biomass air turbine (EvGT-BAT) for biomass feedstock is presented. This process contains a steam-based gasification of biomass, which is integrated in an externally fired gas turbine cycle with top-firing. In the EvGT-BAT process, the steam-based gasification is conducted in an entrained-flow tubular reactor that is installed in the SFC as a heat exchanger. The EvGT-BAT process has the potential to generate electrical power from biomass with an efficiency of 41 %.

Industrial dynamical, Networked Control Systems (NCSs) are controlled over a communication network. We study a continuous-time CANada Deuterium Uranium-Super Critical Water Reactor (CANDU-SCWR) hydrogen plant and a discrete-time controller, sensor and actuator block, that are connected via a communication network, such as e.g. controller area network (CAN), Ethernet or wireless networks. Issues associated with NCSs are time-varying delays, timevarying sampling intervals and loss of data due to packet drop outs. Delays are also associated with software chosen, control system architecture and computation load. CANDU-SCWR hydrogen co-generation model reliability can be analyzed by dynamic flow graph methodology. We have analyzed the CANDU-SCWR feed water integration with the oxygen unit of copper chloride cycle and also conducted an analytical review of the current networked control system delays. / UOIT

<p>This thesis encompasses CO₂ mitigation using three different processes: i) natural gas-fired combined cycle with chemical looping combustion (CLC), ii) trigeneration of electrical power, hydrogen and district heating with extended CLC, iii) steam-based gasification of biomass integrated in an advanced power cycle. </p><p>In CLC, a solid oxygen carrier circulates between two fluidised-bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO₂ separation occurs. In this thesis, CLC has been studied as an alternative process for CO₂ capture in a natural gas-fired combined cycle (NGCC). The potential efficiency of such a process using a turbine inlet temperature of 1200 °C and a pressure ratio of 13 is between 52 and 53 % when including the penalty for CO₂compression to 110 bar. It is shown that this efficiency cannot be further improved by including an additional CO₂ turbine. Two conceivable reactor designs for CLC in an NGCC are presented. Top-firing has been studied as an option to overcome a temperature limitation in the CLC reactor system. The degree of CO₂ capture is shown versus the temperature in the CLC reactor and its combustion efficiency. CLC has the potential to reach both a higher efficiency and a higher degree of CO₂capture than conventional post combustion CO₂ capture technique. However, further research is needed to solve technical problems as, for example, temperature limitations in the reactor to reach this potential. </p><p>Extended CLC (exCLC) is introduced, in which hydrogen is not only produced but also inherently purified. The potential efficiency of a novel tri-generation process for hydrogen, electricity and district heating using exCLC for CO₂capture is investigated. The results show that a thermal efficiency of about 54% might be achieved. </p><p>A novel power process named evaporative biomass air turbine (EvGT-BAT) for biomass feedstock is presented. This process contains a steam-based gasification of biomass, which is integrated in an externally fired gas turbine cycle with top-firing. In the EvGT-BAT process, the steam-based gasification is conducted in an entrained-flow tubular reactor that is installed in the SFC as a heat exchanger. The EvGT-BAT process has the potential to generate electrical power from biomass with an efficiency of 41 %.</p>

L’objectiu d’aquesta tesi és estudiar la viabilitat de la integració de la tecnologia dels cicles de refrigeració per absorció ja existent comercialment, en plantes d’energia industrials, comparant els resultants amb l’alternativa convencional formada per cicles de compressió. La metodologia proposada en aquesta tesi es basa en cinc grans apartats: recopilació de dades de la planta d’energia i de la demanda de fred que es pretén cobir, seleccionar els cicles de refrigeració candidats que podrien satisfer l’esmentada demanda de fred, és a dir, establir les alternatives de disseny existents per a subministrar el fred necessari a la planta de procés utilitzant el programa XV, el qual permet la simulació i optimització de plantes d’energia. El tercer pas de la metodologia, es construir un fitxer de dades estàndard on s’introdueixen la topologia de la planta d’energia i les seves característiques específiques, incloent els paràmetres d’operació dels cicles de refrigeració. Al quart pas, es realitza l’optimització de la planta global d’energia utilitzant com a funció objectiu els costos d’operació i les prestacions de la planta i finalment es calculen els costos d’operació i els indicadors econòmics adients per a la selecció de la millor configuració. En aquesta tesi es presenten dues aplicacions pràctiques en una indústria pretroquímica de Tarragona per tal d’avaluar la metodologia proposada utilitzant equips d’amoníac/aigua i d’aigua/LiBr.

With the rising electricity, raw material and fossil fuel prices, as well as the relatively low selling price of steel, the steel industry has been put under strain to produce steel as cost–effectively as possible. Ideally the industry requires a cost–effective, stable source of energy to cater for its electricity and energy needs. Modern High Temperature Reactors are in a position to provide industries with not only electricity, but also process heat. Therefore, a study was conducted into the economic viability of centering the steel industry on nuclear power. This study considered 3 technology options: a nuclear facility to cater for solely the electricity needs of the steel industry; a nuclear facility producing hydrogen for the process needs of the steel industry; and a nuclear facility co–generating electricity and process heat for the steel industry. An economic model for each of the 3 scenarios was developed that factored in the various cost considerations for each of the 3 options. In general, this included the construction costs, operational and maintenance cost, build time and interest rate of the financed amount. For each option, the model calculated the cost of production per unit output. The outputs were electricity for option 1, hydrogen for option 2, and both electricity and process heat for option 3. Each model was optimised based on a realistic best case scenario for the capital and operational costs and respective best case cost per unit outputs for each of the options were calculated. Using the optimised cost model, it was shown that electricity produced from nuclear power was more cost effective than current electricity prices in South Africa. Similarly, it was shown that a nuclear facility could produce heat at a more cost–effective means than by the combustion of natural gas. Hydrogen proved to be not cost effective compared to reformed natural gas as a reducing agent for iron ore. Based on the cost savings, a cash–flow analysis showed that the payback period for a nuclear power plant that produced electricity for the steel industry would be around 12 years at 0% interest and 15 years at 5% interest. Due to the long payback period and lack of certainty in the steel industry, any steel manufacturer would opt for purchasing electricity from a nuclear based electricity utility rather than building a facility themselves. Savings of over $70 million/year were achievable for a 2 million tonne/year electric arc furnace. Overall this analysis showed that electricity generation is the only viable means for nuclear power to be integrated with the steel manufacturing industry. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012.

With the rising electricity, raw material and fossil fuel prices, as well as the relatively low selling price of steel, the steel industry has been put under strain to produce steel as cost–effectively as possible. Ideally the industry requires a cost–effective, stable source of energy to cater for its electricity and energy needs. Modern High Temperature Reactors are in a position to provide industries with not only electricity, but also process heat. Therefore, a study was conducted into the economic viability of centering the steel industry on nuclear power. This study considered 3 technology options: a nuclear facility to cater for solely the electricity needs of the steel industry; a nuclear facility producing hydrogen for the process needs of the steel industry; and a nuclear facility co–generating electricity and process heat for the steel industry. An economic model for each of the 3 scenarios was developed that factored in the various cost considerations for each of the 3 options. In general, this included the construction costs, operational and maintenance cost, build time and interest rate of the financed amount. For each option, the model calculated the cost of production per unit output. The outputs were electricity for option 1, hydrogen for option 2, and both electricity and process heat for option 3. Each model was optimised based on a realistic best case scenario for the capital and operational costs and respective best case cost per unit outputs for each of the options were calculated. Using the optimised cost model, it was shown that electricity produced from nuclear power was more cost effective than current electricity prices in South Africa. Similarly, it was shown that a nuclear facility could produce heat at a more cost–effective means than by the combustion of natural gas. Hydrogen proved to be not cost effective compared to reformed natural gas as a reducing agent for iron ore. Based on the cost savings, a cash–flow analysis showed that the payback period for a nuclear power plant that produced electricity for the steel industry would be around 12 years at 0% interest and 15 years at 5% interest. Due to the long payback period and lack of certainty in the steel industry, any steel manufacturer would opt for purchasing electricity from a nuclear based electricity utility rather than building a facility themselves. Savings of over $70 million/year were achievable for a 2 million tonne/year electric arc furnace. Overall this analysis showed that electricity generation is the only viable means for nuclear power to be integrated with the steel manufacturing industry. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012.

Orientador: José Antônio Perrella Balestieri / Resumo: A cogeração tem sido proposta em diferentes oportunidades para a solução de problemas de atendimento das necessidades energéticas de empresas (ou grupos de empresas em pólos industriais) a partir de combustíveis fósseis e biomassas vegetais, de forma preponderante. Há, contudo, uma forte demanda mundial para que sejam desenvolvidas novas alternativas de geração, bem como fontes energéticas, dentre as quais se destaca o lixo urbano, na medida em que esse colabora fortemente com a ocupação de áreas economicamente rentáveis, bem como com problemas de ordem social e ambiental quando não devidamente gerenciado. Esta Tese tem por objetivo analisar as perspectivas da geração combinada de eletricidade e vapor em pólos industriais a partir da destruição de resíduos sólidos municipais; para tanto, desenvolve-se uma avaliação das principais formas de deposição do lixo urbano, bem como da cogeração em termos dos sistemas empregados. Foi analisada a legislação ambiental de diversos países, com especial destaque para a política ambiental brasileira, de modo a que fossem observadas as diretrizes de emissões preconizadas em nível mundial e de forma comparativa. Neste item, concluiu-se pela adequada formulação apresentada pela legislação brasileira, que contempla os principais limites de qualidade do ar e de emissão em níveis compatíveis com os que vêm sendo praticados internacionalmente. De modo a subsidiar a modelagem apresentada no corpo da Tese, foi desenvolvido um levantamento acerca das características operacionais e de investimento das principais tecnologias de remoção de poluentes atmosféricos, bem como formas alternativas para "produção limpa" de energia. Para que pudesse ser desenvolvida uma formulação de base exergoeconômica e ambiental para o presente estudo, foi realizada uma revisão bibliografia acerca... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: working out problems concerning energetic needs of enterprises (or groups of enterprises in industrial stocks) preponderantly from fossil fuels and vegetable biomasses. There is, however, a strong world demand for new generating alternatives, as well as energetic sources, be developed: among them it can be pointed out urban waste, while it contributes strongly for the occupation of economically profitable areas and environmental and with not properly managed social problems. This Thesis aims to analyse the perspectives of electricity and steam combined generation industrial stocks from municipal solid waste destruction; therefore, an evaluation of the main forms of urban waste deposition, as well as the cogeneration in terms of the system used is developed. The environmental legislation for a number of countries, with special emphasis for the Brazilian environmental policy, was analysed , so that the emission guidances preconized at a world summit level and at a comparative level could be observed. In this item, the decision was made for the Brazilian legislation, that contemplates the principal air and emission quality limits at levels consistent with the ones worldwide used. In order to subsidize the modeling presented in this Thesis, a gathering of facts on the operational and investment characteristics of the chief technologies for removing atmospheric pollutants, as well as alternate forms for "clean production" of energy was developed. It was performed a bibliographic revision on the principal models used for the calculation of environmental costs, to allow the development of a formulation on environmental and exergoeconomic basis for the present study, as well as alternative models which, yet not showing environmental utilization, could, that way, be considered with small modifications. For the analysis of cogeneration with municipal solid... (Complete abstract, click electronic address below). / Doutor

With limited indigenous conventional energy resources, Mauritius imports over 80% of its energy supply from foreign countries, mostly from the Middle East. Developing independent renewable energy resources is thus of priority concern for the Mauritian government. A tropical island surrounded by the Indian Ocean, Mauritius has enormous potential to develop various renewable energies, such as solar energy, biomass energy, wind power, geothermal energy, hydropower, etc. However, owing to the importance of conventional fossil energy in generating remarkably cheap electricity, renewable energy has not yet fully developed in Mauritius, resulting from a lack of market competition. So, in order to reduce the external dependency of fuel, and also to cut down the expenses involved in the imported fuels, the Mauritius Government introduced attractive policies and invited investors of the homeland and abroad to invest in renewable energy technologies. Consequently, numerous promotional and subsidy programs have recently been proclaimed by the Mauritian government, focused on the development of various renewable energies. Thus, the Government of Mauritius has a long-term vision of transforming Mauritius into a sustainable Island. One important element towards the achievement of this vision is to increase the country’s renewable energy usage and thereby reducing dependence on fossil fuels. Democratisation of energy production is determined to be the way forward. A step in this direction is to transfer citizens the ability and motivation to produce electricity via small-scale distributed generation (SSDG), i.e. wind, photovoltaic, Hydropower. As a stepping stone the Government and the Central Electricity Board, with the help of the UNDP, established a grid code in May 2009 which encompasses tariffs and incentive schemes that have in many countries proved essential in order to achieve any substantial development in renewable electricity production based on SSDG.   In line with the government’s vision on renewable energy, the University of Mauritius is working as a partner with DIREKT team to promote renewable energy infrastructure locally. The DIREKT (Small Developing Island Renewable Energy Knowledge and Technology Transfer Network) is a teamwork scheme that involves the participation and collaboration of various universities from Germany, Fiji, Mauritius, Barbados and Trinidad &amp; Tobago.  The aim of the DIREKT project is to reinforce the science and technology competency in the domain of renewable energy through technology transfer, information exchange and networking, targeting ACP (Africa, Caribbean, Pacific) Small Island developing states. This study was therefore initiated to investigate the main renewable energy technologies that stakeholders, institutions as well as businesses and organizations would like to invest in Mauritius based in the attracting incentive schemes provided by the Government.   From the study it was found that the majority of the Organizations, Institutions, Businesses and stakeholders are ready to accept and invest in the solar photovoltaic technology. Moreover, the economic evaluation for the implementation of the photovoltaic technology revealed that within a period of 4.3 years (payback period), the total capital invested can be recovered and after that, the capital generated from the excess electricity produced will contribute to the profit of the organization, Business or Institution.

With limited indigenous conventional energy resources, Mauritius imports over 80% of its energy supply from foreign countries, mostly from the Middle East. Developing independent renewable energy resources is thus of priority concern for the Mauritian government. A tropical island surrounded by the Indian Ocean, Mauritius has enormous potential to develop various renewable energies, such as solar energy, biomass energy, wind power, geothermal energy, hydropower, etc. However, owing to the importance of conventional fossil energy in generating remarkably cheap electricity, renewable energy has not yet fully developed in Mauritius, resulting from a lack of market competition. So, in order to reduce the external dependency of fuel, and also to cut down the expenses involved in the imported fuels, the Mauritius Government introduced attractive policies and invited investors of the homeland and abroad to invest in renewable energy technologies. Consequently, numerous promotional and subsidy programs have recently been proclaimed by the Mauritian government, focused on the development of various renewable energies. Thus, the Government of Mauritius has a long-term vision of transforming Mauritius into a sustainable Island. One important element towards the achievement of this vision is to increase the country’s renewable energy usage and thereby reducing dependence on fossil fuels. Democratisation of energy production is determined to be the way forward. A step in this direction is to transfer citizens the ability and motivation to produce electricity via small-scale distributed generation (SSDG), i.e. wind, photovoltaic, Hydropower. As a stepping stone the Government and the Central Electricity Board, with the help of the UNDP, established a grid code in May 2009 which encompasses tariffs and incentive schemes that have in many countries proved essential in order to achieve any substantial development in renewable electricity production based on SSDG.   In line with the government’s vision on renewable energy, the University of Mauritius is working as a partner with DIREKT team to promote renewable energy infrastructure locally. The DIREKT (Small Developing Island Renewable Energy Knowledge and Technology Transfer Network) is a teamwork scheme that involves the participation and collaboration of various universities from Germany, Fiji, Mauritius, Barbados and Trinidad &amp; Tobago.  The aim of the DIREKT project is to reinforce the science and technology competency in the domain of renewable energy through technology transfer, information exchange and networking, targeting ACP (Africa, Caribbean, Pacific) Small Island developing states. This study was therefore initiated to investigate the main renewable energy technologies that stakeholders, institutions as well as businesses and organizations would like to invest in Mauritius based in the attracting incentive schemes provided by the Government.   From the study it was found that the majority of the Organizations, Institutions, Businesses and stakeholders are ready to accept and invest in the solar photovoltaic technology. Moreover, the economic evaluation for the implementation of the photovoltaic technology revealed that within a period of 4.3 years (payback period), the total capital invested can be recovered and after that, the capital generated from the excess electricity produced will contribute to the profit of the organization, Business or Institution.