176 resultados para fuel ethanol analysis


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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With the large penetration of the natural gas into the Brazilian energy structure, industries such as paper mills and chemical plants are analyzing the feasibility of implementing cogeneration schemes appropriate to this fuel. The analysis of the energy demand patterns of a chemical company from the photographic sector revealed the possibility of using combined cycles or diesel engine cogeneration schemes keeping the existing compression refrigeration units and steam or gas cycle cogeneration systems with absorption refrigeration units. In terms of economic attractiveness, an analysis based on the method of the internal rate of return was performed. The results indicated that the schemes composed by reciprocating engines and combined cycle with compression chillers, as well as the gas cycle scheme with absorption chiller, present return periods of up to 3 years, showing that the investment in cogeneration could be of interest for this plant. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

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Pós-graduação em Biotecnologia - IQ

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Sugarcane (Saccharum sp.) is an important grass cultivated in tropical and subtropical regions of the world, such as in Br, Ind, and Ch, and has its biomass being raw material for production of sugar, fuel ethanol, and some other derivatives. Fungal diseases infect sugarcane fields worldwide, damaging crops and thus, causing great economic losses. Fungal specialized structures act during all Pathogen-Host Relationship Cycle (PHRC) (survival, dissemination, infection, colonization, and reproduction of pathogen), maintaining fungal populations in cultivation soil, infecting plants in following crops and vegetative propagation of sugarcane by infected seeds may allow fungal transportation into regions where diseases haven’t occured before. Biotechnological methods and approaches have significantly contributed to understanding of the relationship among parasite and host, as to diseases management (control, detection, and prevention). Some techniques have daily applications in Agriculture, while others are only used in research and to breeding of host resistant varieties. Among notable diseases, smut (Sporisorium scitamineum) and pineapple disease (Ceratocystis paradoxa) are important because they cause damage and losses in sugarcane regions, although there are different periods for each one to occur. This work aims to review the PHRC for each patosystem, the biotechnological methods and approaches and its perspectives in the study and management of these diseases. As environment is an important factor to the effectiveness of PHRC, one chapter is dedicated to Global Climate Change (GCC) and its possible influences over these diseases in a longterm period

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Mecânica - FEB

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Fuel cell as molten carbonate fuel cell (MCFC) operates at high temperatures. Thus, cogeneration processes may be performed, generating heat for its own process or for other purposes of steam generation in the industry. The use of ethanol is one of the best options because this is a renewable and less environmentally offensive fuel, and is cheaper than oil-derived hydrocarbons, as in the case of Brazil. In that country, because of technical, environmental, and economic advantages, the use of ethanol by steam reforming process has been the most investigated process. The objective of this study is to show a thermodynamic analysis of steam reforming of ethanol, to determine the best thermodynamic conditions where the highest volumes of products are produced, making possible a higher production of energy, that is, a more efficient use of resources. To attain this objective, mass and energy balances were performed. Equilibrium constants and advance degrees were calculated to get the best thermodynamic conditions to attain higher reforming efficiency and, hence, higher electric efficiency, using the Nernst equation. The advance degree (according to Castellan 1986, Fundamentos da Fisica/Quimica, Editora LTC, Rio de Janeiro, p. 529, in Portuguese) is a coefficient that indicates the evolution of a reaction, achieving a maximum value when all the reactants' content is used of reforming increases when the operation temperature also increases and when the operation pressure decreases. However, at atmospheric pressure (1 atm), the advance degree tends to stabilize in temperatures above 700 degrees C; that is, the volume of supplemental production of reforming products is very small with respect to high use of energy resources necessary. The use of unused ethanol is also suggested for heating of reactants before reforming. The results show the behavior of MCFC. The current density, at the same tension, is higher at 700 degrees C than other studied temperatures such as 600 and 650 degrees C. This fact occurs due to smaller use of hydrogen at lower temperatures that varies between 46.8% and 58.9% in temperatures between 600 and 700 degrees C. The higher calculated current density is 280 mA/cm(2). The power density increases when the volume of ethanol to be used also increases due to higher production of hydrogen. The highest produced powers at 190 mA/cm(2) are 99.8, 109.8, and 113.7 mW/cm(2) for 873, 923, and 973 K, respectively. The thermodynamic efficiency has the objective to show the connection among operational conditions and energetic factors, which are some parameters that describe a process of internal steam reforming of ethanol.