923 resultados para acetone reforming


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One of the biggest challenges today is to develop clean fuels, which do not emit pollutant and with viable implementation. One of the options currently under study is the hydrogen production process. In this context, this work aims to study the technical and economical aspects of the incorporation process of hydrogen producing by ethanol steam reforming in the sugar cane industry and MCFC (molten carbonate fuel cell) application on it to generate electric power. Therefore, it has been proposed a modification in the traditional process of sugar cane industry, in order to incorporate hydrogen production, besides the traditional products (sugar, ethylic, hydrated and anhydric alcohol). For this purpose, a detailed theoretical study of the ethanol production process, describing the considerations to incorporate the hydrogen production will be performed. After that, there will be a thermodynamic study for analysing the innovation of this production chain, as well as a study of economic engineering to allocate the costs of products of the new process, optimising it and considering the thermoeconomics as being as an analysis tool. This proposal aims to improve Brazil's position in the ranking of international biofuels, corroborating the nation to be a power in the hydrogen era. (C) 2013 Elsevier Ltd. All rights reserved.

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Pós-graduação em Educação Escolar - FCLAR

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Pós-graduação em Engenharia Mecânica - FEG

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As características estruturais de sonogéis obtidos a partir da hidrólise ácida do TEOS estimulada por ultrasom foram estudadas por espalhamento de raios-x a baixo ângulo (SAXS). O estudo inclui: i) o processo de agregação em diferentes temperaturas; ii) o envelhecimento dos géis úmidos na fase líquida de preparação e depois da troca da fase líquida por álcool e acetona; iii) a secagem dos géis; iv) a estrutural evolução de xerogéis e aerogéis com o tratamento térmico até 1100 oC; e v) um estudo comparativo usando SAXS e adsorção de nitrogênio na caracterização de aerogéis e xerogéis... (Resumo completo, clicar acesso eletrônico abaixo)

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The bee Apis mellifera has a great importance because it is the most economically valuable pollinator for crops worldwide, ensuring cross-pollination and increasing fruit yield. Moreover, agriculture increasingly develops chemicals to control weeds, fungi and insect pests to ensure productivity. Insecticides are used on a large scale in the state of São Paulo, in cultures of citrus for control of greening. Applications are usually made by aircraft and as a result of the effect derives a significant mortality is observed in apiaries near the plantations. Honey bees can get in contact with such chemical agent through their activities of water harvesting, plant resins, pollen and nectar. Intoxication resulting from this exposure can be lethal, which is easily detectable, or cause effects on the physiology and behavior of the insect. These, in turn are hardly detectable, such as paralysis, disorientation, behavioral changes, but can compromise the entire social structure of the colony, therefore aimed to study the effects of the insecticide Thiamethoxam behavior of honeybees A. mellifera. Newly emerged individuals and with 10 days of age were tested. Applications of 1 μL de Thiamethoxam, diluted in acetone, were made on the dorsal thorax with a microapplicator. Preliminarily, it was observed LD50 twenty four hours after topical treatment of Thiamethoxam. It was found that the LD50 for newly emerged honeybees is 8 ng/bee and for honeybees with 10 days of age is 18 ng/bee. The behaviors were analyzed 1 hour after application of insecticide at doses corresponding to LD50/100, LD50/50, LD50/10 and LD50, besides the control group. In the test reflex proboscis extension, there was impairment of behavior at doses of 8 and 18 ng/bee workers in newly emerged workers and 10 days of age, respectively. And in locomotor behavior was no change only at a dose of 18 ng/bee workers at 10 days of age... (Complete abstract click electronic access below)

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Considering that persistent organic pollutants (POPs) including synthetic substances belonging to differents organic functions, including organochlorine pesticides (OCPs), which are the most persistent and bioaccumulative, with high toxicity to humans and animals. Accordingly environmental and biological monitoring is necessary, in order to have greater control regarding the irresponsible use of these products. Though there are several analytical methodology reported in the literature to make determinations of this pesticide, they present some difficulties, requiring several steps to make the clean up of the sample. The proposed project aims to optimize a new analytical method that allows to perform the extraction of organochlorine pesticides in fish tissues, employing acetone as solvent assisted by ultrasound bath, making the method more quickly and not requiringfurther steps to purify the sample. Were analyzed the recoveries of pesticides in study in samples of tilapia average values: Heptachlor=84,7±9,8%; Aldrin=87,3±3,5%; Endosulfan=101,4±18,6%; DDE= 90,5± 3,3%, Endrin=102,2±13,8%., DDD=92,1±19,9%; DDT=90,8±6,8%. The real samples showed values granted for our legislation and low values of error

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A new approach to generating clean energy has been studied by several researchers, among which one can highlight the steam reforming of biogas. The Biogas is result of decomposition of organic matter and it hasn’t been availed in the global level, instead, the biogas has been burned in flare or discarded into the atmosphere providing damage to the environment. The generation of vector biogas energy can be realized through its steam reforming and this work examines briefly the types of digesters used for biogas generation, studying the process of steam reforming to generate hydrogen as energy vector, analyzing each step in detail, seeking to adapt its main features an ethanol reformer for a biogas reformer. Besides this it is estimated the yield of the reform process and the boiler efficiency for efficiency of the process

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The purpose of this work is to study the incorporation of hydrogen production (Case A) and the process of gasification of sugarcane bagasse associated with combined cycle gas turbine and steam turbine (Case B) for Distillery Pioneers process. These technologies can be used to improve the energy supply in the sugarcane mill. Initially the processes for obtaining sugar and ethanol from sugarcane is discussed, with a theoretical introduction to hydrogen, the process of steam reforming and gasification of biomass (bagasse) by inserting a turbine associated with the recovery boiler gas. Subsequently makes up the energy and exergy analysis of the incorporation of the above technologies. In end stage makes it an ecological analysis considering or not the carbon cycle (photosynthesis), to determine the levels of emissions of pollutants, carbon dioxide equivalent, indicators of pollution and ecological efficiencies associated with technological developments proposed. It is concluded that hydrogen production by steam reforming of ethanol and gasification of bagasse are viable alternatives from the point of view of technical and environmental applications in the biofuels industry, contributing to the development of the sector in the country

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This work studies the incorporation of new technologies in the sugarcane sector. Are considered the ethanol steam reforming and the gasification of sugarcane bagasse(by-product) processes associated with combined cycle systems (Gas Turbine + Steam Turbine), aggregating hydrogen production and increased electricity supply in the sector, respectively. To verify the technical feasibility of the incorporation processes was performed a thermodynamic analysis, considering data from a typical Brazilian Sugar Cane Industry. In another step the economic viability study of the hydrogen production process was made, with consideration on hydrated and anhydrous ethanol steam reform, comparing the cost of hydrogen production. Also considered studies of economic engineering of the gasification process and the generation of electricity associated. As conclusions, it follows that the ethanol steam reforming is a great alternative for hydrogen production, presenting production cost relatively low, especially when is considered the steam reforming of hydrated ethanol. For the gasification process associated with combined cycle, can be observed an increase of 8.56 times of the electricity production in the sugar cane industry, indicating a positive annual saving when the sales price of the supply electricity is greater than 0.070 US$/kWh. Finally it can be concluded that the incorporation of these new processes allow greater profitability and operational flexibility of Brazilian sugarcane mills

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Hydrogen is known as a clean energy resource. The biological production of hydrogen has been attracting attention as an environmentally friendly processs that does not consume fossil fuels. Cellulosic plant and waste materials are potential resources for fermentative hydrogen production. Cellulose is a linear biopolymer of glucose molecules, connected by β-1,4-glycosidic bonds. Enzymatic hydrolysis of cellulose requires the presence of cellulase. The present study aimed to investigate the efficiency of acid pretreatment on ruminal fluid in order to enrich H2 producing bacteria consortia to enhance biohydrogen rate and substrate removal efficiency. In this study, fermentative hydrogen producers were enriched on cellulose (2g/L) in a modificated Del Nery medium (DNM) at 37ºC and initial pH 7.0 using rumen fluid (10% v/v) as inoculum. To increase the hydrogen production it was added cellulose (10mL) to the medium. The gas products (mainly H2 and CO2) was analyzed by gas chromatography (Shimadzu GC 2010) using a thermal conductivity detector. The volatile fatty acids and ethanol were also detected by GC using a flame ionization detector. Cellulose degradation was quantified by using the phenolsulfuric acid method. Analysis showed that the biogas produced from the anaerobic fermentation contained only hydrogen and carbon dioxide, without detectable methane after acid pretreatment test. On DNM the hydrogen production started with 4 h (5,3 x 105 mmol H2/L) of incubation, and the maximum H2 concentration was observed with 34 h (7,1 x 106 mmol H2/L) of incubation. During the process, it was observed a predominance of acetic acid and butyric acid as well as a low production of acetone, ethanol and nbutanol in all experimental phases. Butyrate accounted for more than 77% of total. As a result of the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system was reduced to 4,0. On microscopy analyses there were observed rods with endospores. The batch anaerobic fermentation assays performed on anaerobic mixed inoculum from rumen fluid demonstrated the feasibility of H2 generation utilizing cellulose as substrate. Based on the results, it can be concluded that the acid treatment was efficient to inhibit the methanogenic archaea cells present in rumen fluid. The rumen fluid cells present a potential route in converting renewable biomass such as cellulose into hydrogen energy.