Mestrado em Engenharia Química (IQ)

URI Permanente para esta coleçãohttp://200.137.215.59/tede/handle/tde/267

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Análise da dinâmica de partículas em um leito de jorro pseudo bidimensional por meio de experimentos e simulações Euler-Lagrange usando código open-source
(Universidade Federal de Goiás, 2024-07-29) Antunes, Gabriella Gonçalves Borges; Santos, Dyrney Araújo dos; http://lattes.cnpq.br/8987869956010169; Santos, Dyrney Araújo dos; Duarte, Cláudio Roberto; Mariano, Felipe Pamplona
The spouted bed equipment is characterized by effective solid-fluid mixing, promoting intense contact between the involved phases. For this reason, it is a fundamentally important piece of equipment for the industry, as some industrial processes require an adequate rate of mass, energy, and momentum transfer. Among the operational difficulties in using a spouted bed are systems involving particles with different physical characteristics, such as diameter, shape, and density, resulting in non-uniform products and the emergence of operational instabilities during the scale-up process. Therefore, a systematic study of particle dynamics within the bed is of fundamental importance for optimizing industrial processes and improving the quality of final products. Considering the above, the general objective of this work was to study the crucial aspects of particle behavior in a pseudo-2D spouted bed through experiments and CFD-DEM (Euler-Lagrange approach) numerical simulations, using both a monoparticle system and a binary particle mixture system. To obtain a robust CFD-DEM model, the proposed methodology included the measurement of DEM parameters through experimental data, a rigorous assessment of the independence of computational mesh size concerning particle size, and a detailed analysis of turbulence models and wall boundary conditions for the fluid phase. The CFD-DEM simulations, incorporating the k-ω SST turbulence model and full-slip wall boundary conditions for the fluid phase, satisfactorily represented the experimental behavior of particle dynamics over time. It was possible to observe phenomena such as internal spout formation, main spout channel characteristics, the development of cavities and bubbles, and particle recirculation. The application of the Fast Fourier Transform (FFT) to the simulated temporal distribution of average volumetric particle velocities allowed the identification of both the pulsating regime of particles and the occurrence of multiple fountain regions within a pseudo-2D spouted bed. The number of collisions and collision force between particles were highly dependent on the initial particle load and the air velocity at the bed entrance. The study of binary particle mixtures, both experimentally and through simulations, allowed for a better understanding of particle behavior in a pseudo-2D spouted bed. The assessment of the segregation index, conducted experimentally and through simulations, showed typical mixing equipment behavior: as mixing progresses, the segregation index gradually decreases until reaching a pseudo-steady state. The higher the fluid velocity at the bed entrance, the shorter the time required to reach a final mixing condition. By analyzing particle trajectories, it was possible to identify percolation and fluidization mechanisms and analyze the effect of air velocity at the bed entrance on the mixing process. It was observed that the behavior of particles near the equipment wall is highly influenced by the probability of colliding with the nearest wall and being thrown in the opposite direction, as well as their trajectory being influenced by the material of the equipment wall. The analysis of contacts between particles of different diameters showed that, at higher velocities, particles tend to move faster and remain in contact for shorter periods. Thus, although there are more collisions, each collision is brief, and the number of simultaneous contacts may decrease.
Reforma eletroquímica de glicerol em sistema ácido-alcalino com catalisadores de paládio
(Universidade Federal de Goiás, 2023-09-20) Lino, Fernando Miguel de Amorim; Gambetta, Rossano; http://lattes.cnpq.br/4274171691391935; Leon, José Joaquín Linares; http://lattes.cnpq.br/5126547270872842; Leon, José Joaquín Linares; Colmati Júnior, Flávio; Silva, Fábio Moreira da
In the incessant search for change in the energy model by reducing the dependence on fossil fuels, hydrogen is gaining importance as an energy vector and lever to replace combustion engines with fuel cells. Nevertheless, producing hydrogen from non-fossil fuel sources is still a challenge, with an emphasis on electrolytic hydrogen. To close the green cycle, it is possible to connect hydrogen production to renewable sources to supply the required energy. A shortcoming of this process is the high price of the electrolytic hydrogen, between 3.4 and 12 USD per kg, according to the International Energy Agency in its 2023 annual report about the global status of hydrogen technologies (INTERNATIONAL ENERGY AGENCY, 2023), three times higher than “fossil” H2. To boost green hydrogen development, alternatives are mandatory to reduce the cost of electrolytic hydrogen. This dissertation presents an alternative by developing and optimizing an acid-alkaline glycerol electrochemical reformed to cogenerate hydrogen and electricity by applying a transmembrane pH gradient through a Cation Exchange Membrane. Moreover, this work proposes valorizing the endocarp and shell of the macauba wastes to obtain carbon support by hydrothermal treatment. The prepared materials were characterized by measuring the surface area, pore size distribution, functional groups, and the degree of defects and crystallinity. All the used supports were chemically functionalized by treating them with sulfuric, nitric, chlorohydric acid, and hydrogen peroxide to add oxygenated surface groups. With these supports, Pd/C electrocatalysts were prepared by chemical reduction with sodium formate in alkaline medium. The Pd/C electrocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Transmission Electron Microscopy, and quantifying the electrochemically active surface area by CO stripping. Vulcan XC-72 carbon black was used as a reference support, following the same protocol as the macauba carbon supports. The preliminary electrochemical results evidenced the potential of the alternative carbon supports, stimulating their ulterior application in the acid-alkaline electrochemical reformer. The temperature and the flow rate were optimized, taking the hydrogen produced as the output variable. Preliminary electroreforming experiments under the optimum conditions were galvanostatically carried out, evaluating the amount of hydrogen, electricity, and glycerol oxidation products obtained. With the best Pd/C material (Vulcan XC-72 treated with hydrogen peroxide), it was possible to produce 0.528 Nm3 m-2 h -1 of H2 with a concomitant energy of 0.725 kWh m-2 . In addition, it was possible to obtain high-added-value products such as glyceric, tartronic, and oxalic acid as the most abundant glycerol electro-oxidation products. The system demonstrated to be an alternative for glycerine valorization, the main by-product of biodiesel synthesis, capable of diversifying the portfolio (hydrogen and fine chemicals) of this industry with direct implications on the cash flow and the process sustainability. Finally, xi this work also evidences the feasibility of using activated carbon from the thermochemical valorization of lignocellulosic wastes from the macauba processing (endocarp and shell).
Avaliação dos parâmetros fermentativos relacionados ao perfil de aminoácidos e vitaminas em diferentes variedades de cana-de-açúcar utilizando Saccharomyces cerevisiae PE-2
(Universidade Federal de Goiás, 2024-03-22) Santos, Tatiane Oliveira dos; Vendruscolo, Francielo; http://lattes.cnpq.br/7105461627589188; Castiglioni, Gabriel Luis; http://lattes.cnpq.br/6050198962131737; Castiglioni, Gabriel Luis; Faria, Fabrícia Paula de; Montano, Inti Doraci Cavalcanti
The sugarcane culture is one of Brazil's main economic activities, being the predominant raw material in bioethanol production, an alternative to fossil fuels for decarbonizing the transportation sector. Although the production process is well elucidated, there are numerous possibilities for optimizing ethanol production. Since almost all ethanol production is done through the fermentation of sugarcane, and yeast have specific nutritional requirements, knowledge of the chemical composition of sugarcane juice is of great importance for achieving the highest efficiency in converting sugars into ethanol. Therefore, this study aimed to characterize the wort obtained from five sugarcane cultivars in terms of sugars, free amino acids, and vitamins. Fermentation assays were performed with the worts of each cultivar separately. Fermentation started with 130 g.L- 1 of total sugars (sucrose, glucose, and fructose) and lasted 72 hours, using the Saccharomyces cerevisiae PE-2 strain. The chemical composition of the worts was determined for sugars, amino acids, and vitamins, before and after fermentation by HPLC. Fermentative parameters such as substrate to biomass conversion factor (Yx/s), substrate to product conversion factor (Yp/s), productivity (ϕ), and fermentation efficiency (η) were calculated and subjected to one-way analysis of variance (ANOVA) and Tukey test, both at a statistical significance level of 5%. All cultivars showed good efficiency in alcoholic fermentation: 86.6% (RB867515), 88.2% (RB044108), 92.6% (RB988082), 93.5% (RB034045), and 97.4% (RB074067). Statistical differences were observed among most fermentative parameters, with emphasis on cultivar RB074067 with higher ethanol production and lower production of secondary metabolites. The quantified amino acids (Ala, Arg, Gli, Glu, Met, Tre, and Val) showed concentration variations among cultivars, as did B-complex vitamins (B1, B3, B5, B6, B7, and PABA). Total consumption of most amino acids and vitamin biosynthesis by yeast during fermentation were observed. The fermentation results highlight cultivar RB074067 as a promising variety for achieving increased industrial alcoholic fermentation efficiency with S. cerevisiae PE-2 without additional costs for nutrient supplementation to correct the wort's chemical composition.
Tratamento de águas contaminadas com glifosato mediante adsorção e eletrólise acopladas
(Universidade Federal de Goiás, 2023-06-23) Pereira, Érica de Mendonça; Léon, José Joaquín Linares; http://lattes.cnpq.br/5126547270872842; Léon, José Joaquín Linares; Souza, Fernanda de Lourdes; Silva, Fabricio Machado
Glyphosate is a wide-spectrum herbicide extensively used in Brazil and worldwide. Its presence in surface and ground water has alerted to the need for alternative removal treatments, since it is a refractory pollutant to conventional water and wastewater treatments. Among the alternative treatments, electrochemical advanced oxidation processes emerge as an option. Nevertheless, these processes are often limited by mass transportation, owing to the low concentration of the target molecules found in hydric bodies. This makes necessary the addition of pre-concentration stages for the ulterior electrochemical treatment. The present work brings a possible alternative by the combination of a previous pollutant accumulation process by active carbon adsorption, followed by the electrochemical regeneration of the pollutant adsorbed to, again, reinitiate a new cycle. In the study of glyphosate adsorption onto activated carbon, the effects of pH and ionic strength were investigated. In the electrochemical regeneration, the effect of current density and the reuse of the adsorbent for multiple treatment cycles were evaluated. Results indicated satisfactory pollutant retention capacity by the adsorbent, especially under acid pH and absence of electrolytes (36 mg g-1). Furthermore, the electrochemical regeneration demonstrated the ability to achieve total mineralization of the pollutant in anodic oxidation on boron-doped diamond electrode and maintenance of 89%, on average, of the specific surface area of the adsorbent after five adsorption/regeneration cycles.
Avaliação da atividade hemaglutinante e antibacteriana dos extratos proteicos intracelulares e extracelulares de bactérias isoladas a partir de corais marinhos
(Universidade Federal de Goiás, 2023-03-30) Pereira, Thairyne Naruan Alves; Castiglioni, Gabriel Luis; http://lattes.cnpq.br/6050198962131737; Castiglioni, Gabriel Luis; Vendruscolo, Francielo; Guillo, Lidia Andreu
For decades, the terrestrial environment was the center of studies, however, research was extended from the terrestrial to the marine scope, in order to discover new molecules. Corals are marine animals that are present in seas, oceans and marine nurseries. These animals can live in symbiosis with several organisms, including bacteria that produce molecules of high biotechnological interest. From the collection, isolation and cultivation of these organisms, it is possible to obtain molecules of biotechnological interest. In this context, this study aims to isolate bacterial colonies from marine corals, evaluate the hemagglutinating activity and antibacterial activity of intracellular and extracellular protein extracts from bacterial colonies isolated from Green Star Polyps and Xenia Pompom corals, and obtain the protein profile of the extracts from SDS-PAGE electrophoresis. Eighteen colonies of bacteria were isolated, 9 colonies from each coral. Crude extracts were obtained from the cultivation of isolated bacteria in two different culture media, which were subsequently subjected to 60% saturation with ammonium sulfate. For the hemagglutinating activity, only the extracellular extracts showed activity, which allows inferring that they may contain proteins that have different biological activities, such as antibacterial and antiviral. Therefore, carbohydrate inhibition was performed, however, there was no inhibition of hemagglutinating activity for the following sugars tested, galactose, fructose, maltose, glucose, xylose, rhaminose and sucrose. Therefore, these extracellular extracts were subjected to antibacterial activity, which was determined by the Minimum Inhibitory Concentration (MIC) method, by the broth microdilution technique, against the microorganisms Escherichia coli, Staphylococcus aureus, Bacillus cereus, Salmonella typhimurium, and Enterococcus faecalis. There was antibacterial activity of three (E1 G13, E2 G13 and E2 P2) of the four protein extracts against Enterococcus faecalis. Protein extracts E1 G13, E2 G13 and E1 P2 showed inhibition of microbial growth against another strain tested, obtaining a concentration of 1000 µg.mL-1 for Escherichia coli. The four extracellular protein extracts obtained hemagglutination for the three blood types tested and are promising antibacterial agents, which can contribute to the expansion of natural products of marine origin.
Avaliação da composição mineral do mosto de cana de açúcar no desempenho fermentativo com cultura mista de leveduras Saccharomyces cerevisiae diagnóstico e solução de problemas relacionados a produção industrial de etanol
(Universidade Federal de Goiás, 2022-12-16) Silveira, Larissa Gabriele Silva; Freitas, Fernanda Ferreira; http://lattes.cnpq.br/0883086742146577; Castiglioni, Gabriel Luis; http://lattes.cnpq.br/6050198962131737; Castiglioni, Gabriel Luis; Vendruscolo, Francielo; Ribeiro, Eloizio Júlio
The International Energy Agency estimates that ethanol from sugar cane reduces the emission of greenhouse gases by 89%. Brazil ranks second in world production of ethanol but still needs to improve in the coming years to reach the decarbonization targets proposed by the National Biofuel Policy. However, the process is consolidated the ethanol production improvement depends on the role performed by several factors as fermentation. Industrial yeasts are inoculated in the fermentation owing to their great fermentation characteristics but it may happen the entrance or appearance of contaminating microorganisms which are called wild yeasts. The process requires a wide range of minerals to reach adequate efficiency and a correct range of macro and micronutrients in the fermentation may improve the functioning of cellular metabolism and prevent the development of wild yeasts. This study aims to analyze the effects of mineral nutrients on ethanol production from synthetic sugarcane juice and a mixed culture of industrial and wild yeast. The industrial yeasts BG-1, CAT-1, FT-858L and PE-2 of the species Saccharomyces cerevisiae were used and the wild yeast was isolated from an Alcohol Power Plant in Goiás and called LFS. The yeasts were identified according to their macromorphological characteristics in the growth of colonies on plates. To assure the experimental reproducibility the synthetic sugarcane juice was used with 16% of sugars (m/v). The fermentation essays were evaluated by high performance liquid chromatography and residual sugars, glycerol, ethanol and acetic acid quantified. Minerals were quantified by atomic absorption spectrometry. The tests were carried out in the proportion of 30% of the wild yeast and 17.5% of each industrial yeast for 72 hours at 30ºC with 2.5 mL of the synthetic sugarcane juice. The inoculum was prepared from the scraping of the yeast present in the sterile plates and the solution mineral was added for the supplementation. The influence of Ca, Fe, Cu, K, P, N, S and Mg ions was evaluated at the end of fermentation through colony population dynamics, sugar residual and ethanol production. The tests showed that nitrogen, magnesium, sulfur and copper favor fermentation while calcium, phosphorus and iron are more prejudicial to the process. To evaluate the relationship between the prejudicial minerals was carried out a simplex-lattice mixture design with 3 components and results showed that excess calcium is prejudicial to ethanol production. Another simplexcentroid mixture design was carried out with the 4 elements identified as favorable in synthetic sugarcane juice with calcium excess and the contamination decreased by 67% with supplementation of nitrogen, magnesium and sulfur. Tests in natural sugarcane juice showed that reduction of contaminating was by 48% and confirmed that nitrogen, magnesium and sulfur are favorable to inhibit wild yeast growth. In conclusion, the tests demonstrated that supplementation of nitrogen, magnesium and sulfur reduces the contamination and increases ethanol production. As a suggestion, the addition of fertilizers with these minerals during the cultivation of sugarcane or in start fermentation may help to improve the industrial process.
Análise termodinâmica do processo de pirólise de microalga a partir do cálculo de equilíbrio químico e de fases simultâneo
(Universidade Federal de Goiás, 2021-05-13) Viegas, Júnnio de Sousa; Souza, Thiago Leandro de; http://lattes.cnpq.br/7431199944070783; Souza, Thiago Leandro de; Silva, Simone Monteiro e; Corazza, Marcos Lúcio
In a scenario where population growth is exponential, the supply of the energy matrix is finite, the processing and use of current sources are extremely harmful to the environment, a new name is pointed out as a sustainable energy source to supply all these issues: microalgae biomass. This is particularly interesting due to its high growth rate, high productivity, adaptability to different habitats, non-competitiveness with agriculture and the results of its processing can be used to produce biofuels, products of high added value of industrial interest, treatment and soil recovery. In addition, we may subject it to a decomposition process to obtain your products (bio-oil, gas and charcoal). In addition, it can be subjected to a decomposition process to obtain its products (bio-oil, gas and charcoal). In this study, a thermodynamic analysis of the pyrolysis of microalgae biomass was carried out, which consists of processing the biomass at high temperatures in the absence or low presence of oxygen. From this work, data were obtained that represent the behavior of the reaction system in chemical and phase equilibrium for different operating conditions, varying temperature and humidity, in which the conditions in which the required products are found in greater and/or less quantities. The method for calculating the chemical and phase simultaneous equilibrium explored was Gibbs minimization, under constant temperature and pressure conditions, by a non-stoichiometric approach. A mixture-model composed of palmitic acid, glucose and glutamic acid was considered to represent the biomass of microalgae. The possibility of forming a liquid phase, simulated by the UNIFAC thermodynamic model, was investigated, using the stochastic particle swarm optimization method, in which the possibility of forming 3 distinct phases was considered, one phase behaving as a mixture of ideal gases, a liquid phase and another solid phase modeled as pure solid carbon. The minimization model was also implemented in the GAMS® software, General Algebraic Modeling System, using the CONOPT non-linear programming solver, in which only formation of solid and gaseous products was considered. The studied pyrolysis reaction was predominantly exothermic, with heat of reaction varying from approximately -32 to -16 kJ/mol. For the studied conditions, there was no prediction of liquid phase in the reaction system. Gaseous products such as H2 and CO2 showed maximum yield, 0.246 and 0.415 mol per mol of carbon fed respectively, both under maximum operating conditions for humidity and temperature, under the same conditions there was a greater potential for thermal energy generation, evaluated by the total heating value.
Produção de hidrogênio a partir de efluente do processo de fabricação de biodiesel
(Universidade Federal de Goiás, 2022-12-21) Teixeira, Isabela Rodrigues; Andrade, Laiane Alves de; http://lattes.cnpq.br/6777831109573242; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Alonso, Christian Gonçalves; Andrade, Laiane Alves de; Souza, Thiago Leandro de; Oliveira, Sérgio Botelho de; Souza, Guilherme Botelho Meireles de
The growing energy demand witnessed stems from the way industrial production processes developed from 1970 onwards with the so-called new industrial revolution. This high demand provoked an escalation in the production of fuels, having been supplied, since then, mainly by fossil fuels. The use of this type of energy source results in the emission of compounds into the atmosphere such as Carbon Dioxide (CO2) and other gases that, if released in large quantities, cause environmental imbalances such as the global warming. Such a scenario reveals the need for an energy transition. The gradual transition from carbon-based fuels to low or no-emissions would contain a likely energy crisis. Recent studies indicate that hydrogen (H2) has great potential as one of the sources capable of complementing the high demand, being a source of clean and sustainable energy. As a result, the treatment of industrial waste aimed at transforming it into clean energy has been quite attractive, since in addition to generating a by-product of great economic value, it also reduces the problem of final disposal. Thus, the present work aims to evaluate the production of H2 from the effluent of the biodiesel industry in a medium containing water under supercritical conditions in a continuous flow reactor, verifying the effect of temperature and feed flow variation on the production of hydrogen and/or synthesis gas generated by the process, performing statistical planning in order to optimize the production of H2 through the Central Composite Design (CCD). The independent variables analyzed were the Feed Flow (Qa) and the Temperature (T) with the temperature varying between 500 and 700 °C and the feed flow between 10 and 25 mL/min. Hydrogen represented the highest percentage among the gases generated in the process, the best condition indicated a percentagem (molar fraction) for H2 of 73.86%, for a temperature of 700°C. Proportionally, the second highest generation gas was CO2, with the highest percentage of 22.39% for a temperature of 529°C. The highest value for gas flow was 5540.80 mL/min (T of 700ºC and Qa of 17.55 mL/min). The response variable studied statistically was the average gas flow (mL/min) compared to the H2 flow (mL/min). The analyses indicated a significant increase in the generation of H2 and gasification of the sample with the increase in temperature, while the feed flow did expressed less influence in relation to the analyzed ranges, but showed a tendency to increase the production of H2 for higher feed flow values. To verify the efficiency of the treatment of the effluent in the supercritical environment, the load of Total Organic Carbon (TOC) and other parameters of the raw effluent were compared with the reduction of these after-treatment. The raw effluent sample that initially had a TOC load of 48250.0 mgC/L, after being subjected to treatment via the supercritical process, showed a greater TOC reduction of 82.62% for test 2, with a Qa of 12. 25 mL/min and temperature of 671°C, in addition to significant reductions in the analyzed parameters, in compliance with national environmental legislation, showing that the process using biodiesel industrial effluent as raw material is efficient for the production of hydrogen and also for its treatment. The use of a homogeneous catalyst based on hydrogen peroxide (H2O2) in order to intensify treatment for removal of TOC showed an improvement in the removal of the organic load of 4.13%.
Análise termodinâmica da gaseificação do licor negro em água supercrítica
(Universidade Federal de Goiás, 2022-01-28) Araújo, Beatriz Mendes Mazon de; Souza, Thiago Leandro de; http://lattes.cnpq.br/7431199944070783; Alonso, Christian Gonçalves; Machado, Guilherme Duenhas; Souza, Thiago Leandro de
Black liquor (BL) is a by-product of the pulp and paper industry process. Its composition is full of organic and inorganic matter and products of lignin’s solubilisation. Nowadays, black liquor has been used as a burning source for the boilers and generates the biggest part of the electricity in the industry where it’s produced. However, the actual process has low efficiency, reduced flexibility, besides promoting the emission of harmful gases and corrosion in boilers. The supercritical water gasification (SCWG) introduces many advantages when compared to current recovery process of black liquor, making possible the generation of high added value gases such as hydrogen and methane and contributing to energetic efficiency of the plants. In this work, a thermodynamic analysis of supercritical water gasification was conducted in a black liquor representative compound, from the Kraft process and eucalyptus wood. The chemical-and-phase equilibrium calculations were performed using Gibbs minimization method, with a non-stoichiometric approach, that is, the direct Gibbs minimization. To simulate the gas phase behaviour, two different models were compared: the ideal gas mixture model and the Peng Robinson state equation with the van der Waals mixing rule. The solid phase was considered as pure graphite carbon. From the simulations performed, a sensitivity analysis of of pressure and temperature influence on the balance composition of the reactive system was conducted, what makes possible to predict behaviors and so, makes easier decision making, saving time and resources. The Results indicate that besides generate value added gases, BLSCWG could also produce more thermal energy when compared to conventional BL recovery process.
Otimização dos processos de adsorção e dessorção da octaetilporfirina de níquel em adsorventes à base de carbono
(Universidade Federal de Goiás, 2021-06-10) Caetano, Gabriela Costa; Ostroski, Indianara Conceição; http://lattes.cnpq.br/9689394915288313; Andrade, Laiane Alves de; Barros, Maria Angélica Simões Dornellas de; Ostroski, Indianara Conceição
Petroporphyrins are aromatic and nitrogenous macrocycles, of organic origin, which occur naturally in oil and also in sedimentary rocks. In addition to being important biomarker parameters, they have several applications, such as in catalysis and photodynamic therapy. However, they cause damage to the catalytic stages in oil refining. Therefore, due to the importance of removing these compounds from their original fraction, adsorption has been proposed as an alternative process to the commonly used extractive and chromatographic methods. Considering the adsorption and desorption processes of nickel octaethylporphyrin (Ni-OEP), the selection of adsorbents (activated carbon, graphite and partially oxidized graphite) and the optimization of the process operating conditions (solvent, temperature and solid/liquid ratio) were performed. In response, the variables for evaluating the adsorption, adsorption capacity (qe), and desorption, desorption percentage (%desorption) processes were maximized through qualitative and quantitative experimental designs. The kinetics, equilibrium and adsorption thermodynamics studies were carried out; and the adsorbent regeneration cycles were evaluated. As validation of the optimized conditions, qe and %desorption were obtained close to 7.12 mg.g-1 and 37.68%, respectively. As for the adsorption kinetics, the model that best fitted the experimental data was the Elovich equation, in which the equilibrium was reached between 540 and 600 min, with qe = 6.83 mg.g-1; while the equilibrium data were better adjusted by the Freundlich model. The obtained thermodynamic parameters suggest that, under the considered conditions, the adsorption process is spontaneous (ΔG0ads < 0) and exothermic (ΔH0ads < 0). An extraction process was also carried out on the bituminous shales, taken from the Irati Formation, and the presence of nickel octaethylporphyrin was found in the extract. The adsorption and desorption processes of Ni-OEP in the real system had behavior similar to those developed in the model system, with approximately 50% efficiency in petroporphyrin separation. The results obtained allowed to infer that the adsorptive mechanism can be based on the formation of acid-base and π-π interactions between the Ni-OEP molecules and the heterogeneous surface of the coconut shell activated charcoal (CAD), with characteristics of chemical and physical adsorption, respectively.
Diagnóstico e avaliação da influência de contaminantes selvagens durante etapas do processo produtivo do etanol
(Universidade Federal de Goiás, 2021-01-20) Santos, Camila Oliveira dos; Castiglioni, Gabriel Luis; http://lattes.cnpq.br/6050198962131737; Castiglioni, Gabriel Luis; Vendruscolo, Francielo; Rodriguez, Armando Garcia
Ethanol production represents an important share in the national economy. With the use of sugarcane as a raw material, Brazil is positioned as the second largest producer in the world. Although the ethanol production process is well established, many factors contribute to its efficiency, such as the quality of the raw material, process conditions and microbial contaminants. Sugarcane juice must is a very complex substrate and allows the development of other yeasts of the genus Saccharomyces and non-Saccharomyces, so the microbial population during industrial fermentations can be quite dynamic, and the yeast can be completely replaced in wild yeast process. In view of this, this study proposes to study the fermentative characteristics of contaminating yeast strains isolated from six stages of the production process of an ethanol producing plant in the state of Goiás and the implications that these yeasts could have on the final ethanol yield. The samples were collected from the final melasse, must, concentrated broth, decanted broth, yeast from the vat and fermented wine. From the colonies isolated from the fermented wine, a wild yeast strain with rough appearance and irregular edges was found at a contamination level of 77.4 % of the sample. Thus, fermentative tests were carried out in triplicates with synthetic must of sugar cane with 120 g.L-1 of sugars with a period of 72 hours of fermentation. Firstly, the performance of fermented wine isolated yeast (LFS) was evaluated in comparison with the industrial strains Saccharomyces cerevisiae BG-1, CAT-1, FT-858L and PE-2. LFS obtained lower values in final ethanol concentration, productivity and fermentative efficiency compared to industrial strains. However, in LFS mixed culture fermentative tests at contamination levels of 2, 10, 20 and 30 % with strains BG-1, CAT-1, FT-858L and PE-2, the LFS showed higher levels of final contamination than the initial, thus showing the competence of industrial yeasts over wild yeast, in these same conditions with reuse of the inoculum, the LFS was reduced from 30 % to 0.2 % at the end of 10 consecutive fermentations. In this study, the isolated LFS yeast became more dominant in mixed culture fermentations with the PE-2 strain and in must with calcium oxide additions, between concentrations of 0.05 g.L-1 and 0.30 gL-1 of CaO the results showed a significant drop in fermentation efficiency. The wort of the plant presented an additional calcium concentration of 0.09 g.L-1 after the liming treatment, this concentration is worrying considering that in the tests with the concentration of 0.10 gL-1 of CaO, it was observed that the speed growth rate of LFS was greater than that of the PE-2 strain, possibly this was the condition that favored the critical contamination situation observed in the plant samples, and may mention the possibility of replacing calcium oxide in liming treatment or alternatives that minimize the presence of Ca2+ ions in the must so that it does not favor the development of flocculating yeasts.
Investigação da dinâmica de formação de gotas no interior de microcanais via técnicas de CFD
(Universidade Federal de Goiás, 2020-02-18) Chaves, Igor Lima; Santos, Dyrney Araújo dos; http://lattes.cnpq.br/8987869956010169; Santos, Dyrney Araújo dos; Coltro, Wendell Karlos Tomazelli; Souza, Thiago Leandro de
Microfluidics has a recent origin and its development is based on microanalytical methods. Defined as the science and technology that addresses the manipulation of small amounts of fluids flowing into channels of tens to hundreds of micrometers, microfluidics today has a diversity of applications due to their characteristics of control efficiency. In this work, the microfluidics applications are briefly addressed, the physical characteristics phenomena that govern it are elucidated by identifying the general flow characteristics, the relevant phenomena and dimensionless studies of flow in channels on the micro-scale, as well as the interfacial properties, which appear in multiphase systems. The mathematical basis used to study the flow phenomena is still addressed. Computational fluid dynamics (CFD) techniques are used as a methodology for development, to overcome the limits of laboratory experimentation (observed here the numerical control of the value for interfacial properties). For the study of multiphase microfluidic flows, the Multiphase Fluid Volume Model (VOF) is used, which allows the flow to be solved numerically and to observe its behavior through the interfaces between immiscible fluids. Given this, in this work, the VOF model was validated with experimental results, both quantitatively and qualitatively, to predict the entire process of generating drops within microchannels. Additionally, the Adaptive Mesh Refining (AMR) technique was used to better track the interface between the fluid phases. The effects of the microchannel geometry, the physical properties of the fluids and the operating conditions, on the size and rate of droplet generation were evaluated using the multiple regression techniques. A dimensionless correlation was also proposed for the prediction of droplet length in which the relative error was 8.2%.
Avaliação do uso de carvão ativado na remoção de compostos nitrogenados básicos em diferentes derivados do petróleo
(Universidade Federal de Goiás, 2020-02-28) Carvalho, Matheus Antoniel Félix de; Ostroski, Indianara Conceição; http://lattes.cnpq.br/9689394915288313; Oliveira, Sérgio Botelho de; Andrade, Laiane Alves de; Ostroski, Indianara Conceição
In the reserves of heavier oils, high concentrations of nitrogenous compounds found, which, in general, cause problems for the refining process and for the environment. The removal of these compounds through an adsorptive process, later associated with the traditional hydrodesnitrogenation process, is a promising and favorable technique, especially from an economic and operational point of view. In this context, this research sought to study the denitrogenation of oil samples, through an adsorptive process in a batch system, using chemically treated acid activated carbon. Initially, the solution of indoline in toluene was used as a synthetic filler and different activated carbons were evaluated for the ability to remove the compound. From the preliminary test, the use of activated carbon from coconut shell treated with sulfuric acid (CDAS), resulted in the removal of 97.95% of the indoline present in the solution, and was selected for kinetic and equilibrium study. The adsorption kinetics revealed a relatively fast process for the different concentrations studied. The kinetic data were better adjusted to the pseudo-second order model and the balance data were better adjusted to the Freundlich model. Competitive adsorption tests were also carried out between two nitrogenous, quinoline and indoline, with greater removal amounts being observed in solutions with a higher proportion of indoline. Subsequently, the study of adsorption of basic nitrogenous compounds in a crude oil sample was carried out using the central composite planning technique and response surface methodology. The analysis of the main effects showed that the most significant in the adsorption process was the mass of adsorbent. With the optimized variables (54oC, 150 rpm and 1.104g), a removal of 30.77% of basic nitrogenous compounds in oil was obtained. With the optimal conditions, adsorption tests were performed using vacuum residue, diesel S-10 and diesel S-500, in which the removals obtained were 21.56%, 44.44% and 62.09% respectively. Finally, the analysis of mass spectrometry and thermogravimetry proved qualitatively that the adsorption of nitrogen compounds present in the samples occurred.
Proposta de uma nova metodologia para a determinação da transição catarateamento-centrifugação utilizando partículas esféricas e não-esféricas em um tambor rotatório via técnicas de CFD
(Universidade Federal de Goiás, 2020-02-18) Benedito, Wanessa Mendonça; Santos, Dyrney Araújo dos; http://lattes.cnpq.br/8987869956010169; Santos, Dyrney Araújo dos; Souza, Thiago Leandro de; Petri Júnior, Irineu
Rotary drums are widely utilized in several industrial processes, such as drying, mixing, milling, granulation, among others. The widespread frequent use of rotary drums is due to their simple design and their capability to handle materials characterized by broad size distributions with significant differences in their physical properties. The granular flow inside rotary drums can be classified in different forms: sliding, slumping, rolling, cascading, cataracting, and centrifuging regimes. This classification depends on the drum operating conditions and the physical properties of the particulate material envolved in the granular flow. There are have been no reposts in the literature that presents a precise methodology for cataracting-centrifuging transition identification in rotary drums. This identification is carried out exclusively by visual and subjective way. In this context, the present work aims the proposition of a methodology for the cataracting-centrifuging transition identification, for different particle shapes, using the Multiphase Granular Eulerian Model (MGEM), implemented by CFD simulations. When compared to the Lagrangian model (DEM), the mainly difficult associated with Eulerian model is the particle shape representation, since the solid phase is treated as continuous in CFD simulations. The particle shape for non-spherical particles was indirectly represented in the MGEM using the critical solid fraction (αsc), a parameter associated with the Schaeffer’s frictional model. The present work is also dedicated to overcoming this difficulty. The drum length effect on the cataracting-centrifuging transition was also analyzed. Using the methodology herein proposed was verified that the particle shape and the drum length influence the cataracting-centrifuging transition behavior. For nonspherical particles was required lower values of rotation speed to reach the centrifuging regime condition when compared with spherical particles. It was verified that the lower the drum length, the higher the facility associated with the transition for centrifuging regime for both particle shapes.
Utilização de resíduos de grãos de cervejaria na absorção do corante reativo azul 5G em soluções aquosas: sistemas batelada e leito fixo
(Universidade Federal de Goiás, 2020-02-06) Costa, Fabíola Melazo Amorim Silva; Seolatto, Araceli Aparecida; http://lattes.cnpq.br/1495882445078650; Freitas, Fernanda Ferreira; http://lattes.cnpq.br/0883086742146577; Freitas, Fernanda Ferreira; http://lattes.cnpq.br/0883086742146577; Seolatto, Araceli Aparecida; http://lattes.cnpq.br/1495882445078650; Ostroski, Indianara Conceição; Oliveira, Sérgio Botelho de
The textile sector is a major consumer of freshwater and its growing development results in the generation of large quantities of potentially toxic waste in watercourses, representing a serious threat to man and the environment. Biological treatment does not always present an effective solution for this type of effluent, leading to the need to use alternative treatment processes. Adsorption is an option that stands out due to its high efficiency and versatility, provided that a viable adsorbent is used for industrial application. This work aimed to study the adsorption of Reactive Blue 5G dye (RB5G), in a batch and fixed-bed system, using brewer spent grains (BSG) as an adsorbent. The adsorbent was characterized by particle size analysis, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and point of zero charge. A rotational central composite design (RCCD) was carried out in the study of batch adsorption and a complete factorial planning for the fixed bed, seeking to find conditions that could favor the dye adsorption process. The characterizations showed that BSG is a heterogeneous material, with an irregular surface and with the presence of pores, in addition to having functional groups on its surface that may be involved in the adsorption process. The adsorption kinetics was obtained, presenting an adsorption equilibrium time of approximately 24 h and a dye removal of 91.5%. Batch adsorption kinetics data were fitted to the pseudo- first-order and pseudo-second-order models, and the pseudo-second-order model was the one that best fitted the experimental data. The result of the statistical design performed for the batch system indicated that the dye adsorption capacity by the BSG was favored when the highest temperature values and lowest values of pH and mean particle diameter (MPD) were used. The adsorption isotherm was obtained under conditions capable of maximizing the result of adsorption capacity, and its data were adjusted to the Langmuir and Freundlich models. The Langmuir model was the one that best adjusted the isotherm data, reaching a maximum adsorption capacity of 83.42 mg g-1 . Considering fixed-bed adsorption, the statistical planning used showed that lower flow rates, associated with higher temperatures and adsorbent masses, resulted in a better performance of the adsorption column. The equilibrium data for the fixed bed were found and presented a good fit for both the Langmuir model and the Freundlich model, which may suggest the coexistence of chemical and physical adsorption. In general, the BSG showed good results for the adsorption of the dye RB5G, thus being an alternative for the removal of this dye.
Análise da segregação axial e radial em um leito de jorro cônico
(Universidade Federal de Goiás, 2020-02-17) Morais, Jéssika Nayara Santos; Santos, Dyrney Araújo dos; http://lattes.cnpq.br/8987869956010169; Duarte, Claudio Roberto; Freitas, Fernanda Ferreira
The particle cyclic and orderly movement inside a spouted bed has as main advantages of this technique, thus enabling an effective particle-particle and fluid-particle contact, which results in high transfer rates of heat, mass and movement. Due to their intrinsic characteristics, spouted beds have been widely used in industrial processes, however, there are some disadvantages operation inherent, the most complex of which are related to the segregation phenomenon, which occurs due to the multicomponent mixtures use in production lines, causing a non-uniform product formation, which compromises the equipment performance. In this way, a better understanding of the segregation phenomenon inside a spouted bed, is of fundamental importance for its design, operation and optimization. In the present work, a non-intrusive methodology using a solidification-slicing approach was used for the investigation of radial and axial segregation behavior in a spouted bed. The effects of diameter, density, and shape of the particles, as well as the initial particle loading, and the inlet air velocity, on segregation were qualitatively and quantitatively assessed. Regarding the results, binary mixtures with aspect, diameter and density ratios, equals a 2.0, 2.0, and 1.9, respectively, show a random mixture condition. Binary mixtures with diameter ratio of 4.5 and density ratio of 5.8, show radial and axial segregation. As regards to radial segregation, the higher or denser particles, tended to form a central core at the spout region, and the smaller or lighter particles, flowed to the annular region near the spouted bed wall. The particle dynamics seemed not to be significantly affected by changing the particle initial loadings in systems with aspect ratio of 2.0 and density ratio of 5.8, however, affected systems with diameter ratio of 4.5. As expected, the increase in diameter and density ratios caused an increase in radial and axial segregation. The segregation phenomenon for binary mixtures with high density ratio, were shown to be dependent of the initial particle loading configuration, but independent of the superficial gas velocity.
Estudo da capacidade de adsorção do carvão ativado de osso bovino para remoção de ácidos naftênicos em mistura modelo e real de querosene de aviação
(Universidade Federal de Goiás, 2020-02-07) Santos, Débora Federici dos; Ostroski, Indianara Conceição; http://lattes.cnpq.br/9689394915288313; Alonso, Christian Gonçalves; Pereira de Sá, Fernando
Aviation kerosene is one of the petroleum derivatives obtained by the distillation of crude oil at temperatures ranging from 150 to 300 oC. The presence of naphthenic acids in this fuel provides thermal instability and increased acidity, which consequently increases the corrosion effect on aircraft engines. Naphthenic acid removal can be obtained by adsorption employing porous materials. Thus, the main objective of this work was to evaluate bovine bone activated charcoal (CAB) for its ability to remove n-dodecanoic acid (AD) in model and real mixture of aviation kerosene through data experimental obtained in kinetics and adsorption isotherm. In the kinetic assay, the equilibrium was reached at 180 min for model mixture and 180 min for real mixture, and the theoretical models that best fits the experimental data were pseudo-first and pseudo- second order, respectively. The results indicated a relatively fast adsorption when compared to the use of other adsorbents presented in literature, such as mesoporous sieves and modified perovskites. In the adsorption isotherm, it was found that the amount adsorbed in the equilibrium in model and real mixture was 600 and 780 mg g -1 , respectively. The model with the best fit was that of Freundlich. It was possible to recover the CAB after the adsorptive process by thermal regeneration. Finally, a comparative study was carried out, regarding the efficiency of AD removal, between the CAB and the polymer filtration system used by the fuel distribution company. CAB was the most efficient and could become a viable, inexpensive and regenerative option for use as a filter material.
Investigação do processo oxidativo avançado (UV/H2O2/carvão ativado) no tratamento de efluentes industriais: eliminação de fenol
(Universidade Federal de Goiás, 2017-06-30) Martins, Michelly Freitas de Moraes; Oliveira, Tatianne Ferreira de; http://lattes.cnpq.br/2017895913160804; Castiglioni, Gabriel Luis; http://lattes.cnpq.br/6050198962131737; Castiglioni, Gabriel Luis; Oliveira, Tatianne Ferreira de O; Ostroski, Indianara Conceição; Sá, Fernando Pereira de
Due to the need for more efficient technologies for the phenol elimination in effluents, the objective of this study was to evaluate the efficiency of the UV/H2O2/AC process and the adsobent behavior in the coupling to eliminate phenol. For a determination of the physical characteristics of the activated carbon, a textural analysis was carried out for isotherms of adsorption and desorption of N2 at 77 K, scanning electron microscopy, thermogravimetric analysis and differential thermal analysis. Regarding the chemical nature of the coal were carried out as techniques of infrared spectroscopy, elemental analysis, Boehm method and zero load point. Adsorption kinetics were used to determine the adsorption capacity, for each of the 11 tests, according to the experimental design 23 + 3 central points, where the pH, temperature and the quantity of carbon activated varied. The experimental data obtained in adsorption kinetics were adjusted to the kinetic models of pseudo-first order, pseudo-second order and intraparticle diffusion, with pseudo-second order being the best represent the adsorption process of all the tests. Adsorption isotherms (15, 30 and 45°C) were then adjusted, adjusting the values to the Langmuir and Freundlich models. All feared a better fit of the data to the Freundlich model. For the treatments H2O2/UV and H2O2/UV/AC a factorial design 22 + 3 central points was used, varying pH and H2O2 concentration and quantified response by rate of phenol removal. For both treatments the pH showed a negative release on elimination rate and a concentration of H2O2 showed positive effect. The best tests for H2O2/UV and H2O2/UV/AC processes were the central points (pH 7 and 20 mmol H2O2), with phenol elimination rates of 89% and 94.16%, respectively. With the presence of a free radical inhibitor (tert-butanol) the kinetic contribution of the hydroxyl radicals was calculated, showing that 77.64% of the phenol elimination in the H2O2/UV/AC treatment was caused by their action. The H2O2/UV/AC coupling process is acceptable, presenting a higher removal rate than the adsorption process with much shorter removal time.
Políticas ótimas de alimentação de substrato e enzima em reator de hidrólise operado em batelada alimentada: uma abordagem de controle ótimo com validação automatizada
(Universidade Federal de Goiás, 2019-08-29) Borges, Alex de Souza; Montaño, Inti Doraci Cavalcanti; http://lattes.cnpq.br/8547423775951223; Suarez, Carlos Alberto Galeano; http://lattes.cnpq.br/5911055089145779; Suarez, Carlos Alberto Galeano; Nucci, Edson Romano; Castiglioni, Gabriel Luis
The use of fossil fuels contributes to the increase in the amount of free carbon in the atmosphere, because most of the released carbon does not return to the Earth's surface, boosting the global temperature increase. Biofuels are a renewable and environmentally safe alternative, inasmuch as in its production depends that the carbon present in the atmosphere be captured through photosynthesis forming a cycle of production and consumption of carbon. The use of cellulosic leavings is a Muito promising alternative for the production of biofuels as 2G ethanol. The main reason is the fact that these leavings do not enter the competition "food vs fuels " what happens with 1G ethanol. For the consolidation of the industrial production of 2G bioethanol, the economic improvement of the process is necessary. For this reason, there are several researches that seek to make feasible the technique, in this project, a way is presented to improve the feeding of bioreactors, in order to increase the efficiency of cellulose hydrolysis by releasing reducing sugars, which could be converted into second generation alcohol. The use of fed-batch reactors reduces production costs and increases yields, enjoying of rational feed policies of substrates and biocatalysts. Then, this project intends to determine by means of a computational study, the optimized feeding profiles of cellulosic substrate and fed batch enzyme. For this, a semi- mechanistic model is developed, and the optimal control theory for the development of feed profiles is used. For the application of the feed profiles, a system was designed and built, able to automate the feed for both bioreactors and reactors, which alBaixo s to operate with different feeding profiles. The prototype used 3D printing technology to manufacture the mechanical devices, the entire control is done by two microcontrollers in half duplex network, in charge of acting on a helical conveyor. Due to the ability to work with nonlinear systems, the fuzzy nebulous logic was established as the base of the system, being responsible for carrying out the operations necessary to keep the feeder fully operational.
Sistemas catalíticos heterogêneos para reações de acoplamento Stille-Migita
(Universidade Federal de Goiás, 2019-08-27) Godoy, Pedro Henrique Machado; Oliveira, Guilherme Roberto de; http://lattes.cnpq.br/8239498431579015; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Alonso, Christian Gonçalves; Ostroski, Indianara Conceição; Chagas, Rafael Pavão das
Carbon-carbon coupling reactions are of fundamental importance in the synthesis of organic compounds. The Stille-Migita reaction is a cross-coupling reaction and occurs when an organotin compound and an organic halide hybridized to sp3 react under the presence of a metal-based catalyst, generally palladium. The reaction has the advantage of being compatible with virtually any functional group and for forming products with complex chains, such as pharmaceuticals and agrochemicals. However, Stille synthesis is usually performed by homogeneous catalysis, which enhances the need for costly purification processes necessary to remove metal debris from the reaction products. Thus, this work synthesized and verified the use of heterogeneous catalysts for Stille coupling reactions, using the efficient and economical method of wet impregnation in its preparation by producing monometallic catalysts with different oxides as support. The catalysts were characterized before and after calcination by thermogravimetry and differential thermal analysis (TG / DTA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), textural analysis by adsorption/desorption isotherms of N2 and X-ray fluorescence (XRF). The reaction parameters were optimized: time, temperature, type of solvent and catalyst composition. The materials La2O3/Pd and TiO2/Pd showed no catalytic activity, whereas the catalysts Nb2O5/Pd and SiO2/Pd showed good conversions, above 80%. The recycling tests showed considerable loss of activity, which could be associated with filtration and leaching of the active phase between cycles. Nb2O5/Pd showed higher efficiency in the presence of non-toxic solvents (water/ethanol), unusual in Stille reactions. It is expected that this work will contribute to the development of heterogeneous catalysis, particularly in the coupling reactions, since economical methods of synthesis have produced catalytically active materials.

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