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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.
41

Análise energética do processo experimental de produção de biodiesel a partir de óleo de frango

Bonometo, Ricardo Pacheco [UNESP] 01 September 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-01Bitstream added on 2014-06-13T19:52:22Z : No. of bitstreams: 1 bonometo_rp_me_botfca.pdf: 282254 bytes, checksum: a2dad01e970c5bd5c29c202bdf98cbdf (MD5) / Atualmente há uma grande preocupação mundial com o esgotamento e o alto custo de exploração das reservas de combustíveis fósseis e, portanto, mais do que nunca, é necessário o aprofundamento do estudo e aproveitamento de fontes alternativas que possam ser utilizadas com eficiência energética, preços adequados e com baixo impacto ambiental. De acordo com estas premissas, o biodiesel é um combustível com boas perspectivas de atender uma demanda crescente, pois além de substituir o óleo diesel, pode ser obtido a partir de várias fontes primárias de origem animal e vegetal. O Brasil se destaca na utilização das fontes alternativas de energia com o uso do etanol e, nos últimos anos vem incentivando a ampliação de sua matriz energética a partir das fontes alternativas, na qual o biodiesel passa a ter uma importância estratégica dentro da área de agronegócios. O biodiesel é um combustível que pode substituir o diesel, que é um derivado do petróleo; é um éster produzido na reação de transesterificação de óleos vegetais, goduras animais que, na presença de um álcool, metanol ou etanol, e um catalisador, são convertidos em ácidos graxos e, resultam, em ésteres com glicerol como subproduto. Com o avanço da utilização destes biocombustíveis são necessárias pesquisas que visam melhorar a qualidade e viabilidade técnica dos mesmos, sendo que, o balanço energético é um dos parâmetros mais adequado para definir a viabilidade técnica, pois estabelece a relação entre o total de energia contida no combustível e aquela investida em todo o processo de produção. O objetivo deste trabalho foi analisar energeticamente o processo de produção de biodiesel a partir do óleo dos resíduos descartados na produção de frango. Para a estimativa deste balanço de energia quantificou-se o poder calorífico de alguns... / Nowadays there is a great global concern with the depletion and the high cost of fossil fuel reserves exploitation, more than ever, it is necessary to make a profound study and take advantage of alternative sources that can be used with energy efficiency with an appropriate pricing and with low environmental impact. Under these assumptions, biodiesel is a fuel with good prospects of meeting a growing demand, as well as being a replacement of diesel oil, can be obtained from several primary sources of animal and plant origin. Brazil, which has highlighted in use of alternative energy sources with the use of ethanol and, in recent years, has been encouraging the expansion of its energy matrix in which the biodiesel will have a strategic importance within the agrobusiness area. Biodiesel is a fuel that can replace the diesel,that is a petroleum derivative. It is an ester, produced in the transesterification reaction of vegetable oils and animal greases, that in the presence of an alcohol like methanol or ethanol with an additional catalyst, are converted into fatty acids and result in esters with glycerol as subproducts. The advancement in use of biofuels, some researchs needed improve the quality and feasibility and that energetic balance is one of the most appropriate parameters to define the technical feasibility, since settle the same relationship between of total energy in the biofuel and the total energy invested in the whole production process. The objective of this study was to estimate the final energy balance for the process biodiesel production from oil chicken waste. The energy balance estimation was quantified in calorific value according the energy expenditure by calorimetric bomb method. The study was conducted in CEDETEC - Center for Development and Dissemination of Technology, Department of Agronomy... (Complete abstract click electronic access below)
42

Análise energética do processo experimental de produção de biodiesel a partir de óleo de frango /

Bonometo, Ricardo Pacheco. January 2009 (has links)
Orientador: José Roberto Corrêa Saglietti / Banca: Osmar de Carvalho Bueno / Banca: Reginaldo F. dos Santos / Resumo: Atualmente há uma grande preocupação mundial com o esgotamento e o alto custo de exploração das reservas de combustíveis fósseis e, portanto, mais do que nunca, é necessário o aprofundamento do estudo e aproveitamento de fontes alternativas que possam ser utilizadas com eficiência energética, preços adequados e com baixo impacto ambiental. De acordo com estas premissas, o biodiesel é um combustível com boas perspectivas de atender uma demanda crescente, pois além de substituir o óleo diesel, pode ser obtido a partir de várias fontes primárias de origem animal e vegetal. O Brasil se destaca na utilização das fontes alternativas de energia com o uso do etanol e, nos últimos anos vem incentivando a ampliação de sua matriz energética a partir das fontes alternativas, na qual o biodiesel passa a ter uma importância estratégica dentro da área de agronegócios. O biodiesel é um combustível que pode substituir o diesel, que é um derivado do petróleo; é um éster produzido na reação de transesterificação de óleos vegetais, goduras animais que, na presença de um álcool, metanol ou etanol, e um catalisador, são convertidos em ácidos graxos e, resultam, em ésteres com glicerol como subproduto. Com o avanço da utilização destes biocombustíveis são necessárias pesquisas que visam melhorar a qualidade e viabilidade técnica dos mesmos, sendo que, o balanço energético é um dos parâmetros mais adequado para definir a viabilidade técnica, pois estabelece a relação entre o total de energia contida no combustível e aquela investida em todo o processo de produção. O objetivo deste trabalho foi analisar energeticamente o processo de produção de biodiesel a partir do óleo dos resíduos descartados na produção de frango. Para a estimativa deste balanço de energia quantificou-se o poder calorífico de alguns... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nowadays there is a great global concern with the depletion and the high cost of fossil fuel reserves exploitation, more than ever, it is necessary to make a profound study and take advantage of alternative sources that can be used with energy efficiency with an appropriate pricing and with low environmental impact. Under these assumptions, biodiesel is a fuel with good prospects of meeting a growing demand, as well as being a replacement of diesel oil, can be obtained from several primary sources of animal and plant origin. Brazil, which has highlighted in use of alternative energy sources with the use of ethanol and, in recent years, has been encouraging the expansion of its energy matrix in which the biodiesel will have a strategic importance within the agrobusiness area. Biodiesel is a fuel that can replace the diesel,that is a petroleum derivative. It is an ester, produced in the transesterification reaction of vegetable oils and animal greases, that in the presence of an alcohol like methanol or ethanol with an additional catalyst, are converted into fatty acids and result in esters with glycerol as subproducts. The advancement in use of biofuels, some researchs needed improve the quality and feasibility and that energetic balance is one of the most appropriate parameters to define the technical feasibility, since settle the same relationship between of total energy in the biofuel and the total energy invested in the whole production process. The objective of this study was to estimate the final energy balance for the process biodiesel production from oil chicken waste. The energy balance estimation was quantified in calorific value according the energy expenditure by calorimetric bomb method. The study was conducted in CEDETEC - Center for Development and Dissemination of Technology, Department of Agronomy... (Complete abstract click electronic access below) / Mestre
43

Sécurité des machines : méthodologie d’identification systématique des phénomènes dangereux en conception / Machine safety : method for systematic hazard identification during design

De galvez, Nicholas 12 December 2016 (has links)
Les concepteurs de machines de production doivent prendre en consideration les differents aspects des produits tels que la technologie, la legislation et la securite professionnelle. la directive europeenne 2006/42/ce definie les principes de prevention des risques professionnels. destinee aux concepteurs de machines, son objectif est d’imposer la necessite d’obtenir le niveau de risque le plus faible possible selon l’etat de l’art. bien que les concepteurs de machines catalogues ont acces a des normes specifiques pour realiser les analyses a priori, ce n’est pas le cas pour les concepteurs de machines speciales. une approche originale appelee ezid est presentee dans ce papier pour aider tous les concepteurs de machine pour l’identification des phenomenes dangereux.basee sur le fait que les phenomenes dangereux sont lies a la presence d’energie, ezid les identifie au travers de la detection des parametres de conception lies aux sources et flux d’energie. elle renvoie ensuite de maniere organisee les informations relatives a tous les echanges d’energie potentiels entre les operateurs et la machine aux concepteurs, mettant en lumiere le besoin d’ajouter des solutions pour la prevention des risques. / Machine designers must take into account different aspects of products such as technology, legislation and occupational safety. european directive 2006/42/ce promulgates machine safety design principles to prevent occupational risks. aimed at machine designers, its objective is to set out the need to obtain the lowest possible risk level according to the state of the art. although the designers of catalog machines have access to specific standards to perform a priori risk analyses, this is not the case for special machine designers. an original approach called ezid is presented in this report to help all machine designers in the task of hazard identification.based on the fact that hazards are linked to the presence of energies, ezid identifies hazards through the detection of design parameters linked to energy sources and flows. it then feeds back organized information to designers on every potential exchange of energy between the machine and its operators, bringing to light the need to add risk prevention solutions.
44

An exergy based method for resource accounting in factories

Khattak, Sanober Hassan January 2016 (has links)
In the current global climate of declining fossil fuel reserves and due to the impact of industry on the natural environment, industrial sustainability is becoming ever more important. However, sustainability is quite a vague concept for many, and there are a range of interpretations of the word. If the resource efficiency of a factory is taken as a measure of its sustainability, then the concept becomes better defined and quantifiable. In order to analyse the resource efficiency of a factory and suggest improvements, all flows through the manufacturing system need to be modelled. However the factory is a complex environment, there is a wide variation in the quality levels of energy as well as the composition of material flows in the system. The research presented in this thesis shows how the thermodynamics-based concept of ‘exergy’ can be used to quantify the resource efficiency of a factory. The factory is considered an ‘integrated system’, meaning it is composed of the building and the production processes, both interacting with each other. This is supported by three case studies in different industries that demonstrate the practical application of the approach. A review of literature identified that it was appropriate to develop a novel approach that combined exergy analysis with the integrated view of the factory. Such an approach would allow a ‘holistic’ assessment of resource efficiency for different technology options possibly employable. The development of the approach and its illustration through practical case studies is the main contribution of the work presented. Three case studies, when viewed together, illustrate all aspects of the novel exergy based resource accounting approach. The first case study is that of an engine production line, in which the resource efficiency of this part of the factory is analysed for different energy system options relating to heating ventilation and air conditioning. Firstly, the baseline is compared with the use of a solar photovoltaic array to generate electricity, and then a heat recovery unit is considered. Finally, both of these options were used together, and here it is found that the non-renewable exergy supply and exergy destruction are reduced by 51.6% and 49.2% respectively. The second case study is that of a jaggery (a sugar substitute) production line. The exergy efficiency of the process is calculated based on varying the operating temperature of the jaggery furnace. The case study describes the modelling of al flows through the jaggery process in terms of exergy. Since this is the first example of an exergy analysis of a jaggery process, it can be considered a minor contribution of the work. An imaginary secondary process that could utilize the waste heat from the jaggery process is considered in order to illustrate the application of the approach to industrial symbiosis. The non-renewable exergy supply and exergy destruction are determined for the baseline and the alternative option. The goal of this case study is not to present a thermally optimized design; rather it illustrates how the exergy concept can be used to assess the impact of changes to individual process operations on the overall efficiency in industrial symbiosis. When considering natural resource consumption in manufacturing, accounting for clean water consumption is increasingly important. Therefore, a holistic methodology for resource accounting in factories must be able to account for water efficiency as well. The third case study is that of a food production facility where the water supply and effluent are modelled in terms of exergy. A review of relevant literature shows that previously, the exergy content of only natural water bodies and urban wastewater had been quantified. To the author’s knowledge, this is the first example of applying this methodology of modelling water flows in a manufacturing context. The results show that due to a high amount of organic content in food process effluent, there is significant recoverable exergy in it. Therefore, a hypothetical water treatment process was assumed to estimate the possible savings in exergy consumption. The results show that at least a net 4.1% savings in terms of exergy could be possible if anaerobic digestion water treatment was employed. This result can be significant for the UK since the food sector forms a significant portion of the industry in the country. Towards the end of the thesis, a qualitative study is also presented that aims to evaluate the practical utility of the approach for the industry. A mixed method approach was used to acquire data from experts in the field and analyse their responses. The exergy based resource accounting method developed in this thesis was first presented to them before acquiring the responses. A unanimous view emerged that the developed exergy based factory resource accounting methodology has good potential to benefit industrial sustainability. However, they also agreed that exergy was too complex a concept to be currently widely applied in practice. To this effect, measures that could help overcome this barrier to its practical application were presented which form part of future work.
45

Projeto conceitual simulação e análise de plantas de produção de etanol a partir do gás de síntese / Conceptual projetct, simulation and analysis of ethanol production plants from syngas

Miranda, Júlio César de Carvalho, 1983- 28 August 2018 (has links)
Orientadores: Maria Regina Wolf Maciel, Rubens Maciel Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-28T02:11:55Z (GMT). No. of bitstreams: 1 Miranda_JulioCesardeCarvalho_D.pdf: 11420052 bytes, checksum: 1d66d50744b41020ecf572a3b96b2561 (MD5) Previous issue date: 2015 / Resumo: O gás de síntese (syngas) é conhecido principalmente pelo seu uso na produção de amônia (Processo Harber-Bosch) e hidrocarbonetos (Processo Fischer-Tropsch). No entano, uma rota menos explorada para a produção de produtos químicos, entre eles alcoóis e outros oxigenados, a partir do gás de síntese, vem ganhando atenção nos últimos anos. Nessa rota, a matéria-prima inicial, como a biomassa é inicialmente gaseificada ao syngas, o qual é reformado, limpo, comprimido e finalmente convertido cataliticamente em uma mistura de alcoóis e produtos oxigenados que, após os passos de separação, atingem a pureza necessária para sua comercialização. Nesse trabalho, a rota termoquímica, como é conhecida, é utilizada com o objetivo de se produzir etanol a partir do syngas. Utilizando o simulador comercial ASPEN Plus v7.3, foram propostos 9 casos de estudo utilizando 3 categorias diferentes de catalisador em 4 diferentes layouts de processo. Todos os casos de estudo foram avaliados quanto à sua produtividade, ao seu consumo de energia e aspectos de importância econômica. Foi possível concluir a partir das análises feitas que cada uma das categorias de catalisador possui vantagens e desvantagens dependendo do contexto econômico, podendo-se citar a diferenciada produção de hidrocarbonetos e outros oxigenados além do etanol, a geração de água, o número de unidades de separação e o consumo de energia / Abstract: Synthesis gas (syngas) is mostly known by its use on ammonia (Harber-Bosch process) and hydrocarbons (Fischer-Tropsch process) production processes. However, a less explored route to produce chemical products, among them alcohols and other oxygenates, from syngas is gaining attention over the last few years. In this route, an initial feedstock as biomass is firstly gasified to synthesis gas, which is reformed, cleaned, compressed and finally catalytically converted in a mixture of alcohols and oxygenated products that after separation steps attain sufficient purity to be sold. In this work, the thermochemical route, as it is known, is used aiming ethanol production from syngas. Using the commercial simulator ASPEN Plus v7.3, 9 case studies were proposed using 3 different categories of catalysts in 4 different process layouts. All the cases were evaluated regarding their productivity, their energy consumption, and aspects of economic importance. It was possible to conclude from the analysis that each of the catalyst categories has advantages and disadvantages depending on the economic context, among them the different proportion of hydrocarbons and other oxygenated products besides ethanol, water generation, number of separation unities and energy consumption / Doutorado / Engenharia Química / Doutor em Engenharia Química
46

A Framework for Better Understanding and Enhancing Direct Contact Membrane Distillation (DCMD) in Terms of Module Design, Cost Analysis and Energy Required

AbuHannoud, Ali 07 1900 (has links)
Water is becoming scarcer and several authors have highlighted the upcoming problem of higher water salinity and the difficulty of treating and discharging water. Moreover, current discoveries of problems with chemicals that have been used for pretreating or post-treating water alerted scientists to research better solutions to treat water. Membrane distillation (MD) is a promising technology that might replace current processes as it has lower pretreatment requirements combined with a tremendous ability to treat a wide range of feed sources while producing very high product quality. If it enters the market, it will have a big influence on all products, from food industry to spaceflight. However, there are several problems which make MD a hot topic for research. One of them is the question about the real cost of MD in terms of heating feed and cooling distillate over time with respect to product quantity and quality. In this work, extensive heating and cooling analyses are covered to answer this question in order to enhance the MD process. Results show energy cost to produce water and the main source of energy loss for direct contact membrane distillation (DCMD), and several suggestions are made in order to better understand and hence enhance the process.
47

Analyzing the Effects of Autonomous Navigation on Row Crop Farming

Eric Kong (11150976) 03 August 2021 (has links)
As the global population rises, so does the demand for food, feed, fiber, and fuel. Meeting this demand has become increasingly difficult due to the decline in farm labor and challenges associated with the economic viability of agricultural systems. Autonomous agricultural machinery has the potential to mitigate some of major challenges that crop production systems will face. Widespread adoption of autonomous machinery is dependent on two key factors, the cost and environmental impact. The development and adoption of autonomous vehicles will only occur if it is profitable for equipment manufacturers and farmers. As distillate fuel use for crop production increases, fuel efficient operations that minimize greenhouse gas emissions will mitigate the environmental impact of farming.<br><div><br></div><div>The objective of this research was to develop a model to quantify the cost, energy use, and emissions associated with the use of agricultural machinery used for row crop farming. The model calculates the cost of different sized machinery fleets for planting and harvest. Autonomy facilitates swarm farming, and the model can quantify and compare these to human-operated machinery systems.<br></div><div><br></div><div>For an 800-hectare case study farm in the Midwest, with the acreage split evenly between corn and soybeans, the most cost-effective planting machinery fleet was comprised of two autonomous, 56-kW JD 5075E tractors pulling 4-row planters ($40/ha/yr). The most cost-effective fleet used the most fuel (4,327 liters) and produced the most emissions (219,735 grams). For a similar conventional system to complete planting during the same working window, it would require 4 tractors and cost $75/ha/yr. The $35/ha/yr difference between the similar fleets was the value added by autonomy. Current row crop farming trends have shifted towards fewer operators with larger machines and implements. The most cost-effective, single operator machinery set from the database (Case Magnum 200 with a 16-row planter) costs $43/ha/yr more than overall most cost-effective fleet. Total fuel used to complete the planting operation was minimized by using a single John Deere 8320R pulling a 36-row planter. To plant all 800-hectares, the 8320R used 2,528 liters of diesel fuel and produced a combined 44,002 grams of emissions. The JD 5075E was able to minimize cost, but it used the most fuel and produced the most greenhouse gas.<br></div><div><b><br></b></div>
48

Trimming of a ground source heat pump system in Saltsjöbaden

Garnier, Michel January 2014 (has links)
The real performance of ground source heat pumps systems are not precisely highlighted in most cases, especially when it comes to installations older than the contractors guarantee period of 5 years. This project analyses measured data, constructs durability diagrams and establishes an energy balance of a whole heating system located in Saltsjöbaden. The system, composed of 3 heat pumps with a total heating power of 270kW and an oil burner, is used to deliver comfort heat through radiators and ventilation as well as tap warm water production. The installation was originally designed with two oil burners now used as an auxiliary heat supplier. Two heat pumps were installed in 1999 and a third unit was added in 2009. However, the oil consumption has been higher than expected. An experiment with controlled oil burner operation confirmed the need of implementing a control strategy. Some weaknesses in the system are pointed out.
49

A Comparative Analysis of Energy ModelingMethods for Commercial Buildings

Salmon, Spencer Mark 11 July 2013 (has links) (PDF)
This thesis researched the accuracy of measured energy data in comparison to estimated hand calculation data and estimated building energy performance simulation data. In the facility management industry, there is minimal evidence that building energy performance software is being used as a benchmark against measured energy usage within a building. Research was conducted to find examples of measured energy data compared to simulated data. The study examined the accuracy of a simulation software and hand calculations to measured energy data. Data suggests that comparisons may be made between building energy performance simulated data and measured data, though comparisons are solely based on each individual case. Data suggests that heating load simulation data is more accurate for benchmarks than cooling load simulation data. Importing models into Autodesk Green Building Studio (GBS) was not as successful as was expected. When only four of the initial ten building models chosen imported successfully, the remaining twenty-five other building models were imported. Only two of the twenty-five models successfully imported into GBS. The sample size of this research changed from ten to six. The results of this study show that GBS simulated data was close to actual data for the heating loads. For the cooling loads, however, GBS simulated data was consistently low in comparison to the actual data. The results of this study show that hand calculations were consistently low and not as close as GBS simulated data when compared to the actual data for the heating loads. The opposite was true with the cooling loads as hand calculations were consistently high in comparison to actual data.
50

Energy, exergy and environmental analyses of conventional, steam and CO2-enhanced rice straw gasification

Parvez, A.M., Mujtaba, Iqbal M., Wu, T. 08 November 2015 (has links)
Yes / In this study, air, steam and CO2-enhanced gasification of rice straw was simulated using Aspen PlusTM simulator and compared in terms of their energy, exergy and environmental impacts. It was found that the addition of CO2 had less impact on syngas yield compared with gasification temperature. At lower CO2/Biomass ratios (below 0.25), gasification system efficiency (GSE) for both conventional and CO2-enhanced gasification was below 22.1%, and CO2-enhanced gasification showed a lower GSE than conventional gasification. However at higher CO2/Biomass ratios, CO2-enhanced gasification demonstrated higher GSE than conventional gasification. For CO2-enhanced gasification, GSE continued to increase to 58.8% when CO2/Biomass was raised to 0.87. In addition, it was found that syngas exergy increases with CO2 addition, which was mainly due to the increase in physical exergy. Chemical exergy was 2.05 to 4.85 times higher than physical exergy. The maximum exergy efficiency occurred within the temperature range of 800 oC to 900 oC because syngas exergy peaked in this range. For CO2-enhanced gasification, exergy efficiency was found to be more sensitive to temperature than CO2/Biomass ratios. In addition, the preliminary environmental analysis showed that CO2-enhanced gasification resulted in significant environmental benefits compared with stream gasification. However improved assessment methodologies are still needed to better evaluate the advantages of CO2 utilization.

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