Mestrado em Engenharia Mecânica
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- ItemUma proposta para medição in-line da distribuição do tamanho de gotas em escoamentos de emulsões e seu desempenho(Universidade Federal do Espírito Santo, 2024-12-03) Pimentel, Cláudio Benincá; Loureiro, Bruno Venturini; Ramos, Rogério; https://orcid.org/0000-0003-4493-2435; Siqueira, Renato do Nascimento; Silva, Fabricio Soares daOil production is generally associated with the co-production of water, and its proportion increases as wells mature. Flow disturbances such as bends, valves, and equipment, which are crucial for controlling production in a safe and sustainable manner, increase shear stresses during flow, leading to the formation of stable emulsions due to the breakage of water droplets dispersed in the oil. Stable emulsions are unfavorable for the oil and gas industry as they hinder the phase separation process (oil/gas/water), resulting in higher consumption of chemical inputs and increased maintenance costs. The efficiency of the separation process is associated with the Droplet Size Distribution (DSD). However, most DSD measurement instruments currently operate through sampling, which exposes the emulsion to the risk of altered characteristics during sample handling. In this study, a device is proposed for measuring DSD using in-line optical microscopy, obtaining DSD through a computer vision-based algorithm from micrographs of droplets dispersed in the emulsion. Experimental procedures for commissioning and performance evaluation of the device, comparing it with conventional DSD measurement techniques, are carried out in a laboratory-scale emulsion experimental circuit available at the Center for Studies in Oil&Gas Flow and Measurement- Núcleo de Estudos em Escoamento e Medição de Óleo e Gás (NEMOG/UFES). The results obtained with the device demonstrate its ability to provide accurate in-line DSD information for water-in-oil emulsions, though with a more limited measurement range compared to the laser diffraction technique. The results are assessed using dimensionless numbers such as Reynolds and Weber, allowing for extrapolation across different scales. The developed device stands out for its simplicity, speed of measurement, and capability for in-line monitoring of emulsions.
- ItemSimulação e avaliação termodinâmica de configurações de sistemas de cogeração a vapor para recuperação energética dos gases exaustos dos fornos de uma carboquímica(Universidade Federal do Espírito Santo, 2024-08-30) Quintão, Alexsander Luíz; Faria, Pedro Rosseto de; Santos, José Joaquim Conceição Soares; https://orcid.org/0000-0003-3695-2014; Donatelli, João Luiz Marcon; Silva, Júlio Augusto Mendes daEnergy efficiency plays a crucial role in the transition to more sustainable energy sources and in the decarbonization of industries. Within this context, the recovery of residual energy from processes stands out as a strategy, as is the case of the carbochemical plant, which is the subject of this study, where the calcination furnaces release exhaust gases containing thermal and chemical energy. These gases, originating from six furnaces, have a total flow rate of 1.36 kg/s at 800°C, with a volumetric composition of 26% H2, 4.2% CH4, and 5% CO, among other gases, resulting in a total energy potential of 8.30 MW. of which 1.63 MW is thermal and 6.67 MW is chemical. This study aims to analyze cogeneration system configurations based on steam cycles for this energy recovery, aiming to heat the thermal oil of the process, in addition to generating electricity. To this end, four configurations were simulated based on an example from Norway, using the IPSEpro software, followed by evaluation based on the first and second laws of thermodynamics to assess their performance and identify opportunities for future optimizations. The results indicated that, in addition to providing useful heat of 70 kW for heating the oil, it is possi-ble to obtain an electrical power of up to 2.654 MW. The energy and exergy efficiencies of the steam cycles reach up to 43.35% and 80.45%, respectively, while the system as a whole achieves up to 32.8% and 32.03% energy and exergy efficiencies, respectively. The exergy analysis revealed opportunities to improve various processes, with the greatest exergy des tructions occurring in the combustion chambers and boilers, in addition to the recoverable heat in the exhaust gases from the boilers. Although the environmental assessment was not the main objective of the study, qualitatively, it was observed that there is a drastic reduction in the temperature of the gases currently released into the atmosphere, as well as the combustion of combustible elements present, mainly methane, drastically reducing thermal and chemical pollution. Furthermore, quantitatively, by generating electricity and thus reducing the demand on the power grid, more than 3,234 tons/year of CO₂ emissions can be avoided. These indicators, as well as the thermodynamic evaluation of these four simulated configurations, demonstrate the significant theoretical potential for recovering this residual energy, which brings substantial benefits in terms of both effici-ency and reduction of environmental impacts. This potential also suggests the need for further studies for other assessments, particularly regarding economic viability, especially if the project is to be enabled for integration into a carbon market.
- ItemParametrização e quantificação do grau de cobertura de pelotas de minério de ferro: aplicação de solução de glicerina como supressor(Universidade Federal do Espírito Santo, 2024-10-23) Cordeiro, Afonso de Jesus; Martins, Márcio Ferreira; https://orcid.org/0000-0002-3023-222X; Mesquita, André Luiz Amarante; Oliveira, Arthur Vieira da SilvaAir pollution generated by dust suspension during the handling of bulk solids, such as ore pellets, poses significant challenges to the mining industry, including Vale S.A. Dust suppression technologies, such as glycerin and water-based solutions, are applied through large nozzles to minimize dust emissions from iron ore. Although the current system has proven effective, the issue of glycerin waste has prompted the evaluation of alternative methods using spray nozzles at strategic points.To optimize the coverage of iron ore pellets with a solution containing 2% glycerin, this study developed methodologies to quantify the wetted area on the pellet surfaces and analyze the wetting mechanisms resulting from the interactions of accumulated droplets. Pellet properties, such as diameter, porosity and roughness, as well as suppressant characteristics, including viscosity and density, were characterized by means of image analysis, optical profilometry, density measurements, droplet penetration tests, empirical equation analysis, data analysis and mathematical evaluations of non-linear curve fitting. A dimensionless number was formulated to predict the degree of saturation in the pellets, by suppressant solution, in order to estimate better spraying conditions.
- ItemAvaliação da usinabilidade de aços de livre corte com adições de chumbo e/ou bismuto(Universidade Federal do Espírito Santo, 2024-10-14) Alves, João Paulo Luiz Grisotto; Barbosa, Patrícia Alves; https://orcid.org/; https://orcid.org/0009-0009-3872-2301; Orlando, Marcos Tadeu D'Azeredo; Machado, Álisson Rocha; Salustre, Mariane Gonçalves de MirandaFree-cutting steels are developed using metallurgical techniques to achieve high machinability through the addition of alloying elements that disrupt the material matrix, enhancing productivity and reducing manufacturing costs. This study aimed to evaluate the machinability of the three free-cutting steels, coded as Steel A (MnS+Pb), Steel B (MnS+PbBi), and Steel C (MnS+Bi). For this purpose, microstructural characterization, hardness tests, and machining tests were conducted, including constant pressure drilling tests (evaluating drilled length, cutting temperature, and chip characteristics) and turning tests (measuring machining force, specific cutting pressure, surface roughness parameters, chip characteristics, and tool wear). In the drilling tests, spindle speed, applied load, and material were varied. In the turning tests feed rate and material were varied. The results indicated that Steel A exhibited a predominantly pearlitic microstructure, while Steels B and C showed ferritic microstructures. These microstructural differences were reflected in the Vickers hardness values, with Steel A showing a hardness 78% and 84% higher than that of steels B and C, respectively. In drilling process, Steel A presented greater machining difficulty, with Steels B and C being the materials with the best machinability responses. Increasing spindle speed or applied load resulted in a higher material removal rate. Lower spindle speed combined with greater applied load resulted in higher temperatures during drilling of free-cutting steels. Increasing applied load contributed to the breakage of the chip, forming shorter chips. Lead and bismuth additions contributed to chip embrittlement, however, only bismuth addition showed tendency to longer and snarled chips formation. In turning process, different microstructures, free cutting elements and hardness promoted changes in the material machinability. At lowest feed rate, FU for Steel C was 105% higher than the others. For f=0.2 mm/rev, FU for Steel A became the superior. And for the greatest feed rate, Steel A showed the better machinability result, presenting a FU value 15.2% lower than Steels B and C. The specific cutting pressure (Ks) showed significant variations depending on the feed rate and materials. Free cutting elements contributed to Ks reduction. The free cutting steels showed similar behavior, increasing roughness with feed rate. Material and feed rate influenced the chip shape during the turning process. In general, chip breaking was facilitated by feed rate increasing. Bi addition contributed to chip embrittlement, making it shorter. Cutting tool used for turning Steel A showed the greatest wear (VBBmáx = 844.523 µm, and crater), the largest build up layer, and evidence of wear mechanisms by diffusion and attrition
- ItemAvaliação da performance de medição de gás úmido pela tecnologia de cone invertido por ciência de dados(Universidade Federal do Espírito Santo, 2024-10-30) Lima, Phelipe Augusto Santos Oliveira; Ramos, Rogério; https://orcid.org/0000-0003-4493-2435; Martins, Marcio Ferreira; Tsuzuki, Marcos de Sales GuerraA particular case of multiphase Cows is that of wet gas, which is present in various industrial sectors such as power generation, the food industry, chemicals, and primarily in the oil and gas industry. Monitoring this Ćow is of utmost importance to meet not only legal requirements but also production outlook and the design and development of new techniques to enhance well efficiency. It is known that the presence of water at high Gas Volume Fractions, in other words, in wet gas conditions, leads to an overreading tendency in measurements by differential pressure meters. Therefore, being a low-cost technology with a well-known physical principle, the use of these meters for wet gas applications is gaining prominence in the industry. Inverted cone meters are the most recent technology in differential pressure Ćow measurement, standing out for their low pressure drop and the requirement for shorter straight pipe lengths when compared to oriĄce plates. Therefore, considering the applicability of statistical inference techniques and the data processing capabilities of data science for multidimensional data, the implementation of various techniques becomes one of the possible tools for assessing the performance of two-phase Ćows. The experimental results obtained indicate a linear relationship between overreading, pressure, and the dimensionless Lockhart-Martinelli parameter. The methodology of this work aims to contribute to the implementation of new techniques for correcting overreading in two phase Ćows.