Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2309
O Mestrado Acadêmico iniciou-se em 1992 e pertence ao Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Navegando Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC por Orientadores "FRANÇA, Luiz Ferreira de"
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Item Acesso aberto (Open Access) Avaliação da influência da natureza da matriz sólida sobre a extração supercrítica de óleos vegetais(Universidade Federal do Pará, 2013-05-10) COSTA, João Fernando Alves; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172The extraction of substances from solid substrates both low and high pressures involves at least two phases, a solid and another fluid. The content of the solute in each phase is expressed in terms of the volume of phase and / or volume of solvent. Then, by modeling the interfacial mass transfer it requires a partition coefficient. In general, the simplest way to address this problem is to model the phases separately. The mechanism predominant mass transfer can vary from system to system. For some substrates higher resistance may be in the solid phase and for others it is in the fluid phase. As the interface concentrations for each phase are represented by different variable, phases have to be modeled separately. However, depending on the system, there may be a transfer mechanism predominated over the other, and many effects can be discarded for simplification of the model. The utilization of simpler mathematical models requires a combination of variables for definition of parameters that can represent the phenomenon. In this work the extraction curves were fitted to a model which describes the interfacial mass transfer like a first order kinetics, since the constant of the extraction rate is the unique adjustment parameter. It has been proposed that the adjustment parameter depends on the solubility of solute in the supercritical solvent and on the solid substratum characteristics. To avail that, extraction experiments with babaçu, powder açaí and pupunha pulp using super-critic carbon dioxide at 20, 25 and 30 MPa and temperature of 50°C have been carried out. The results showed that the experimental data fit well to a model with a constant characteristic of each material, with values 4.1983 x 10-5 m/kg∙s to babaçu, 4.2258 x 10-5 m/kg∙s to pupunha pulp, to 10-5 m/kg∙s to powder açaí.Item Acesso aberto (Open Access) Avaliação do processo de produção de etanol pela fermentação do caldo de mandiocaba (Manihot esculenta Crantz)(Universidade Federal do Pará, 2013-02-28) SOUZA, Leiliane do Socorro Sodré de; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172The physico-chemical characteristics identified at sweet cassava root, was: moistures (%), fiber (%), protein (%), ash (%), total lipids (%), reducing sugars and total reducing sugars (%); the sap extract from sweet cassava root was characterized by pH, soluble solids (%), glucose and titratable acidity. This study used the yeast Saccharomyces cerevisiae PE-2. Was realized 15 tests that followed the conditions determined by the experimental design of Box- Behnken, with 3 independent variables: temperature (oC) (X1), pH (X2) and concentration of inoculum (g/L) (X3). The statistical analysis was performed with p>0,05. Through the analysis of variance (ANOVA) was proposed a second order polynomial model to the alcohol content (ºGl), and by analysis of response surfaces it was determined the optimum condition to the fermentation of sap extract from sweet cassava root without addition of nutrients, on original substrate concentration of it (6,46 g/L): 28ºC (temperature), 4,88 (pH) and 10 g/L (inoculum concentration). Under these conditions a test was conducted, which aimed to raise the curves of cell growth (yeast), CO2 production, consumption of sugars and ethanol production, to better understand the process of fermentation broth of sweet cassava. Through the cellular growth curve was determined the duration of the exponential phase, using the method of linear regression; this step in this study occurred at different time intervals. The value found to μm was 0,05 h-1.Item Acesso aberto (Open Access) Decomposição catalítica do glicerol em fase vapor usando a perovskita cecuxni1-xo3 (x=0;0.25) como precursor catalítico(Universidade Federal do Pará, 2017-03-09) ESTRADA, Marcial Antonio Fuentes; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172; RIBEIRO, Nielson Fernando da Paixão; http://lattes.cnpq.br/0755443458423442The utilization of the fuels fossils like main source of energy has carried to the generation of countless environmental and economic problems, creating the need of diversification of the energetic matrix. In Brazil, country with vast territorial extension and agroindustry very established stands out the production of biofuels, such as: ethanol and biodiesel. Particularly, the production of biodiesel with the increasing governmental incentives exponentially has its production increased to each year placing Brazil in prominence in the worldwide scene of biofuels. In the process of transesterification of vegetal oils with a primary alcohol, beyond biodiesel, the rude glycerin in a ratio of 10% is generated 11% in volume. The bio refining of the deriving glycerin of the manufacture of biodiesel, becomes the production of biodiesel economically more viable, leading to the formation of products with raised aggregate values. For this reason, the present work has as main objective the valuation of the chain of production of biodiesel for the transformation of glycerol to the products of bigger value added through reaction catalytic decomposition of glycerol using perovskitas of the CeNi1-xCuxO3 type (x=0 and 0,25) as you will catalyze. The gotten results had shown that the use of high temperature (500 °C) favors the gas production of synthesis with approach relation H2/CO of 1, this occur for the strong craqueamento of the molecule of glycerol, At 410 ° C and inert reaction atmosphere, hydroxyacetone (acetol) was the major product exhibiting selectivity in the range of 22-28% depending on the catalyst used. The effect of the addition of hydrogen on the reaction load was investigated and its insertion promoted the hydrogenation of the hydroxyacetone, leading to an increase in selectivity for 1,2-propanediol whose selectivity varied in the range of 4-9% depending on the catalyst.Item Acesso aberto (Open Access) Processo de Transformação termoquímica dos cachos sem frutos de dendê (Elaeis guineensis, Jacq)(Universidade Federal do Pará, 2016-05-12) RABELO, Rafael Farias; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172The biomass thermal processing is an important operation to add value to the generated waste by palm oil industries. The objective of this work was to monitor the temperature influence (400, 500, 600 and 700°C) and the particle size in the thermal processing of palm fruit bunches without (PFB). It was used an apparatus for thermal processing containing a 4,4x10-4 m3 reactor, with possible recovery of solid and liquid products. The raw materials used were composed with PFB fractions of different particle size (entire sample (without screening), coarse fraction (retained on a 28 mesh sieve), mean fraction (retained on 60 mesh sieve) and fine fraction (retained in the sieve bottom)), which were properly characterized by immediate analysis, lignocellulosic composition, thermogravimetric and higher calorific power. In the solid products, it was made immediate analysis and higher calorific power value, on the other hand, in the liquid products, it was measured the higher calorific power, the density, the kinetic viscosity and the pH values. The solid maximum efficiency occurred at 400°C temperature, the gaseous product at 700°C temperature and the liquid had equivalent values at temperatures of 400, 500 and 600°C. The experiments raw materials showed lignocellulosic values between 45 to 53% of cellulose, 17 to 23% of hemicellulose and 30 to 40% of lignin in their composition. The thermogravimetric analysis showed higher degradation percentages at 300°C temperature, indicating a higher weight loss relative to the cellulose. The solid product showed higher percentages of fixed carbon and lower volatile percentages at 600 and 700 °C temperatures, also showed significant gains on the calorific power value, the results varied from 40.57 to 55.04% for the entire sample, from 56.74 to 70.12 % for coarse fraction, from 44.22 to 54.25% for mean fraction and 32.77 to 45.52% for fine fraction. The liquid product also showed significant gains in the calorific power value, the results varied from 56.48 to 68.59% for the entire sample, from 71.69 to 85.00% for coarse fraction, from 54.76 to 66.28% for mean fraction and 46.42 to 63.31% for fine fraction. Density values, kinematic viscosity and pH decreased with particle size reduction of PFB.Item Acesso aberto (Open Access) Produção de biodiesel através da hidroesterificação do óleo de andiroba (Carapa guianensis, Aubl.) via Catalise Heterogenea Acida(Universidade Federal do Pará, 2011-06-30) TEIXEIRA, Evilácio Luz; SOUZA, Mariana de Mattos Vieira Mello; http://lattes.cnpq.br/8882084525542926; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172The process of hidroesterification (hydrolysis followed by esterification) is constituted as an alternative to the conventional process for producing biodiesel, because it allows the use of raw materials of any content of fatty acids and moisture. Biodiesel is derived from the esterification of Andiroba oil with high content of fatty acids being used niobium oxide powder (HY-340) from Brazilian Company of Metallurgy and Mining - CBMM – as a catalyst. For the execution of experiments was used an autoclave reactor (batch). The hydrolysis reaction was conducted at 300oC, 1200 psi and molar ratio water/oil equal 20. In the esterification reactions were observed the effects of molar ratio methanol/fatty acid (1,2; 2,1 an 3,0), temperature (150, 175 and 200oC) and the concentration of catalyst (0, 10 and 20%) on conversion and initial rate of reaction. The data were conducted according to experimental design (factorial with 23 and adding 3 plants points) analyzed by the program Statistica. The conversion of esterification reaction was monitored from measurements of titrimetric acidity of aliquots removed at times of 5, 10, 15, 20, 25, 30, 45 and 60 minutes. In the experiments of esterification the highest conversion obtained was 96.1% with temperature of 200 o C, 20% m / m of catalyst and molar ratio methanol / acid equal to 3.0. Eliminating the catalyst and recital the same levels for the other two analyzed variables (temperature and molar ratio), was obtained a conversion of 95.3%, however was observed a conversion rate child, taking-if an increase of 35 minutes in the time of compared with the reaction catalyzed reaction.Item Acesso aberto (Open Access) Produção de biodiesel da gordura de murumuru (Astrocaryum murumuru) via catálise heterogênea(Universidade Federal do Pará, 2010-09-24) TEIXEIRA, Louise Carolina Gonçalves; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172; CORRÊA, Nádia Cristina Fernandes; http://lattes.cnpq.br/5763999772352165This work investigated the feasibility of Murumuru oilseed (Astrocaryum murumuru) as raw material for biodiesel production through the use of heterogeneous catalysis in the basic transesterification. Murumuru is a fruit composed of pulp and kernel, producing about 50% of white fat, odorless, with the advantage of not be tasteless easily because it is rich in saturated fatty acids of short-chain such as for lauric and myristic. The biodiesel is conventionally production through the basic homogeneous catalysis. However this catalysis presents a few inconvenients, such as saponification of esters and the difficulty of removing the catalyst. On the otter hand, the heterogeneous catalytic route avoids the drawbacks of homogeneous catalysis, reducing the amount of aqueous effluent generated during the process and reuse of catalysts. The heterogeneous catalyst hydrotalcite, was synthesized and evidenced by analysis of X-ray fluorescence, X – ray diffraction, thermal analysis, textural analysis (BET method) and electronic scanning microscopy. A complete factorial planning was conducted using methanol as reacting product. Independent variables were temperature, molar ratio and catalyst concentration and the response variable was the conversion, measured through spectrophotometric method. These reactions were conducted in to a pressurized batch reactor. The best conversion found through factorial planning was 88,97% for molar ratio of methanol/oil worth 12, temperature of 200ºC and catalyst concentration equaling 6% in 1 hour of reaction. For this condition, kinetic studies were performed and tested the use of ethanol; through the kinetic study a good correlation can be achieved between the kinetic constants and conversion when using the model that considers reversible reaction, chemical reaction as controlling stage following the Eley Rideal mechanism.