Mestrado em Energia

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Análise da aplicação de ferrita de cobalto em processo de eletrocoagulação para tratar emulsões oleosas residuais
(Universidade Federal do Espírito Santo, 2022-10-27) Vieira, Damaris; Porto, Paulo Sergio da Silva; https://orcid.org/0000000264867813; http://lattes.cnpq.br/7140925853660088; Borges, Raquel Machado; https://orcid.org/0000-0001-8119-7092; http://lattes.cnpq.br/6650916642132386; Bacelos, Marcelo Silveira; https://orcid.org/0000000208386839; http://lattes.cnpq.br/3741207242086712
Fossil fuels account for more than 80% of the world's total energy supply. Produced water (AP) corresponds to 98% of all effluents generated in exploration, drilling and production activities. Due to the potential for pollution of the emulsified oil, disposal in water bodies must comply with the required release standards. Among the emerging treatment technologies, this work investigated the application of cobalt ferrites in the electrocoagulation process, in a batch regime, regarding the potential for removal of synthetic emulsified oil. The effect of the factors: distance between electrodes, polarity inversion and ferrite mass were investigated on the removal efficiency. The distance between the electrodes (DE) and the polarity inversion time (TIn) were the significant parameters in the EC process. The presence of the cobalt ferrite factor in the system promoted an increase in the mass gain of the electrode for Tin in 30s. The magnetic separation of the decanted ferrite-oil and supernatant ferrite-sludge set was effective. The percentage of turbidity removal was greater than 96% in all tests. For operating conditions: DE in 1 cm; Tin of 10 s and 0 g of ferrite mass, the TOG removal percentage was 94%.
Análise da co-pirólise do pseudocaule de bananeira e resíduos plásticos por termogravimetria: caracterização cinética e modelagem por redes neurais artificiais
(Universidade Federal do Espírito Santo, 2023-09-27) Nepomucena, Thâmara Vieira; Lira, Taisa Shimosakai de; https://orcid.org/000000022690242X; http://lattes.cnpq.br/8699243861996813; https://orcid.org/0000-0001-5721-1528; http://lattes.cnpq.br/0749470696531423; Arrieche, Leonardo da Silva; Bacelos, Marcelo Silveira; https://orcid.org/0000000208386839; http://lattes.cnpq.br/3741207242086712; Nariyoshi, Yuri Nascimento
The high oxygen content in bio-oil obtained from the pyrolysis of lignocellulosic biomass may make its use as a fuel unviable. One strategy to mitigate this issue is deoxygenation through co-pyrolysis of biomass with plastic waste. Thus, the general objective of this work was to analyze the co-pyrolysis of banana pseudostem and plastic waste by thermogravimetry. Initially, the results of the chemical characterization indicated polypropylene as the most suitable plastic exhaust for bio-oil improvement, compared to polyethylene, as it contains greater amounts of hydrogen and the absence of oxygen. Subsequently, all parameters used to characterize co-pyrolysis, through thermogravimetric analysis, increased as the proportion of plastics in the mixture increased. This suggests that the initial temperature, maximum mass loss rate, peak temperature, final residual mass, and pyrolysis performance are specific primarily to plastics. Even so, artificial neural networks showed excellent prediction capacity for thermogravimetry data, with brightness coefficients greater than 0.999. The activation energies estimated with the data predicted by the neural networks were very close to those discovered experimentally. Finally, as the main contribution made to the topic of this research and future application of this process, the best conditions presented for the reports: a mixture containing 25% polyethylene mass and 75% banana pseudostem mass, using a heating rate of 30 K/min, and another mixture with 50% polypropylene mass and 50% banana pseudostem mass, using a heating rate of 10 K/min.
Análise do leito de jorro como sistema de contato para pirólise de compósito PEBD/AL
(Universidade Federal do Espírito Santo, 2014-09-11) Melo, Jardel Leno Zancanella; Bacelos, Marcelo Silveira; Ferreira, Maria do Carmo; Arrieche, Leonardo da Silva; Lira, Taisa Shimosakai de; Pereira, Fábio de Assis Ressel
In the last decade, several routes of waste cartons reusing have been proposed in the literature. Among other recovery processes, pyrolysis of carton residues has been highlighted due to make possible the manufacture of products with high added value, such as paraffin oils and aluminum bars. Recently, the spouted bed has been investigated as a promising reactor for pyrolysis of solids, due to its high rate of thermal exchange. However, in order to occur the pyrolysis appropriately is essential the study about the dynamics of air flow between solid residues in conical spouted bed. Thus, this research aims to analyze the flow of the LDPE/Al composite (in the form of pellets, ds = 2,58 mm) and mixtures of LDPE/Al composite and sand (ds = 2.58 mm) in a conical spouted bed. The experimental data of pressure drop are measured by a differential pressure transducer. These are assigned to an A/D interface, National Instruments. and processed on a computer by data acquisition program developed with Labview 10.0. The data of velocity of air are obtained by frequency inverter, which accompanies the experimental apparatus. The Eulerian model is used to describe the flow of air-solid in conical spouted bed. The equations of the model are addressed using the technique of computational fluid dynamics with the finite volume method, using a structured two-dimensional mesh. Among the tested turbulence models, the k-ɛ model dispersed seems to be appropriate to predict characteristic fluid dynamic behavior of the bed. The CFD simulations are adequate in this case study, underestimating the experimental values, where data for the minimum spouting velocity (Vmj), pressure drop of minimum spouting (ΔPmj) and maximum pressure drop in the bed (ΔPmax) have a maximum deviation of -13.5; -9.5 and -23, respectively. Analyzing the stability of the bed, to use mixtures with LDPE/Al composite mass fraction between 20 and 40% is recommended.
Análise do uso de um reator de eletrofloculação cilíndrico contínuo no tratamento de água oleosa
(Universidade Federal do Espírito Santo, 2017-05-16) Andreatta, Domênico; Dalmaschio, Cleocir José; Porto, Paulo Sérgio da Silva; Silva, César Augusto Sodré da; Muniz, Eduardo Perini; Siqueira, Renato do Nascimento; Bacelos, Marcelo Silveira
Análise experimental e numérica do escoamento ar-areia-compósito PEBD/Al em leito fluidizado
(Universidade Federal do Espírito Santo, 2015-12-15) Freitas, Thaís Magnago; Ribeiro, Daniel da Cunha; Bacelos, Marcelo Silveira; Siqueira, Renato do Nascimento; Arrieche, Leonardo da Silva
In the current context in which is endorsed the maximum energy use on recovery routes of solid waste, pyrolysis is a promising technique. In the context of carton packaging waste, this technology is the only one that allows aluminum recovery. In large-scale production, the fluidized bed reactor becomes a promising technique of gas-solid contact system for pyrolysis of polyethylene-aluminum composite (LDPE/Al). However, it still needs a better understanding of polyethylene-aluminum particles fluid dynamics in fluidized bed. In this sense, this study aims to analyze the fluid dynamics behavior of composite (ρs = 1039 kg/m³, ds = 550 µm) and sand (ρs = 2567 kg/m³, ds = 550 µm) particles in fluidized bed in order to contribute to the application of this reactor in pyrolysis of carton packaging waste. To achieve that goal, fluid dynamics tests are carried out to obtain experimental data of pressure drop and bed height as functions of air velocity. A multifluid Eulerian model with granular flow extension is used to simulate the multiphase flow using computational fluid dynamic. The minimum fluidization velocity is obtained through experimental characteristic curve and equations from literature. Its values decrease as the mass fraction of composite in mixture increase, with experimental values of 0,32; 0,30; 0,28; 0,24; 0,22 and 0,13 m/s for systems operating with sand, mixture 1 (95% sand), mixture 2 (90% sand), mixture 3 (80% sand ), mixture 4 (70% sand) and composite, respectively. Restricted to the conditions studied, the flow patterns present in polyethylene-aluminum and sand fluidization are: fixed bed, bubbling fluidized bed and slugging fluidized bed. For the fluidized bed operating with mixtures of composite and sand the segregation phenomena is undesirable and only occurs for low air velocities. The Syamlal-O’Brien (1989) parametric momentum exchange coefficient was appropriate to perform the polyethylene-aluminum flow in fluidized bed. The fluid dynamic behavior investigation of these mixtures in fluidized bed is a fundamental step to determine the ratio of sand and composite and optimal operating conditions to be used in the pyrolysis of these waste.
Avaliação do efeito de variáveis de processo na lixiviação das cinzas de caldeira de recuperação em indústria de papel e celulose
(Universidade Federal do Espírito Santo, 2018-03-22) Barros, Eduardo Lopes de; Nariyoshi, Yuri Nascimento; Bacelos, Marcelo Silveira; Silva, César Augusto Sodré da; Lira, Taisa Shimosakai de
The non-process-elements (NPE’s) in the pulp and paper industry, in particular chloride (Cl- ) and potassium (K+ ), eventually accumulate in the chemical recovering cycle. This accumulation often leads to fouling and corrosion inside the recovery boiler. To overcome such problems, an ash leaching system is typically employed in order to remove Cl- /K+ and recover Na+ /(SO4) -2 from the recovery boiler ashes. In this context, this research proposes to evaluate the effects of temperature, slurry concentration and pH on the separation efficiency of a laboratorial ash leaching system fed with recovery boiler ashes from a pulp and paper mill. As expected from the literature, the result reveals that concentration has the most significant effect on the response variables, whereas pH – not mentioned in the literature – also has a significant effect. The optimum operating conditions (84% sulfate recovery efficiency and 97 % chloride removal efficiency) can be achieved at 60ºC, 50% slurry concentration and pH 9.0.
Co-pirólise de casca de café e polietileno de baixa densidade
(Universidade Federal do Espírito Santo, 2019-02-27) Pimentel, Felipe Santos; Xavier, Thiago Padovani; Lira, Taisa Shimosakai de; Bacelos, Marcelo Silveira; Borel, Lidja Dahiane Menezes Santos
Biomass pyrolysis represents a thermal treatment option aimed at the transformation of wastes into products with high added value, in particular bio-oil. When obtained from the pyrolysis of lignocellulosic biomass, it has a high content of structural oxygen, which becomes an obstacle for use as fuel. An alternative for improving the bio-oil is through the co-pyrolysis of biomass and plastic waste. Thus, the objective of this work is to evaluate the synergy of the co-pyrolysis of coffee husk and low density polyethylene (LDPE) and to analyze the effects of operational variables on the process. The behavior of thermal degradation of coffee husk and LDPE blends containing 0, 25, 50, 75 and 100% LDPE, by mass, was evaluated by means of thermogravimetric analysis, in addition kinetic and thermodynamic parameters were estimated. The mixtures showed synergy, exhibiting high reactivity and the need for smaller amounts of heat supplied for reaction occurrence, mainly the 75% LDPE composition. The following ranges of activation energy values were found: (13.55 - 177.01) kJ/mol, enthalpy: (8.48 - 170.81) kJ/mol and entropy: (-291.8 - -62.95) J/mol. The effects of the variables: final reaction temperature, heating rate and spatial time on the yield of the liquid product were investigated. Based on the statistical analysis, it was verified that the greatest effect on product yield comes from the interaction between temperature and spatial time. In addition, through the desirability function, the values corresponding to the final reaction temperature, heating rate and spatial time to maximize bio-oil production were found to be 873.15 K, 10 K/min and 1.42 min, respectively. And finally, the major compounds in the composition of the bio-oil which are paraffins, followed by olefins, have been identified.
Compósito de Luffa cylindrica e óxido de cobre para a dessalinização da água do mar
(Universidade Federal do Espírito Santo, 2024-09-25) Flores Vasquez, Katherine Jisselle; Bacelos, Marcelo Silveira ; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; Andrade, George Ricardo Santana ; https://orcid.org/0000-0002-1772-9477; http://lattes.cnpq.br/1419428893704446; https://orcid.org/0009-0002-3589-5118; http://lattes.cnpq.br/8713161231510324; Meireles, Carla da Silva ; https://orcid.org/0000-0003-4450-5708; http://lattes.cnpq.br/9685470701740945; Barbosa, Cintya D' Angeles do Espirito Santo ; https://orcid.org/0000-0003-2620-8240; http://lattes.cnpq.br/1197509333716425
The increasing demand for water requires more efficient, economical and sustainable desalination processes. Solar desalination is a promising solution, but its low energy efficiency limits large-scale production. Research indicates that the addition of photothermal absorbing materials (PTMs) can improve this technology. This study aims to develop PTMs by combining loofah (Luffa cylindrica) and Cu2O, to increase the efficiency of conventional solar desalination. Thus, the composites were prepared by adsorbing copper ions on loofah (in natura or after alkaline treatment) followed by a heat treatment at 220ºC. Characterization was performed using OM, XRD, UV-Vis, SEM, ZPC, and thermographic imaging techniques. The XRD results revealed the presence of peaks related to the graphitic phases and Cu2O with cubic structure. OM and SEM/EDS data showed that the loofah structure remained unchanged after heat treatment and that Cu2O particles were uniformly distributed on the surface of the loofah fibers. The composites presented high light absorption in the UV-vis region and, consequently, higher surface temperature after exposure to sunlight. Solar evaporation tests using the composite without alkaline treatment, chosen because it presented the highest surface temperature when exposed to direct solar radiation, resulted in conversion efficiencies between 76.9% and 98.6% for distilled water and 88.1% for seawater. These results indicate the direct influence of the amount and exposed surface of the composite on efficiency. In addition, a distiller with a glass body was designed and built, which, when incorporating the absorbing material, increased the average desalination efficiency by 94%. Physicochemical analyses of the water obtained, such as pH, chloride quantification and electrical conductivity, confirmed the desalination of seawater. The composite showed better conversion efficiency and a significant increase in the productivity of solar distillation than other similar materials in the literature. Therefore, this work innovates by developing a material with high potential for solar desalination, contributing to mitigate the effects of water scarcity
Eletrofloculador contínuo e monitorado para tratar emulsão oleosa sintética: análise da eficiência de separação e do consumo de energia elétrica
(Universidade Federal do Espírito Santo, 2020-03-25) Nascimento, Bárbara Zon; Porto, Paulo Sergio da Silva; https://orcid.org/0000000264867813; http://lattes.cnpq.br/7140925853660088; https://orcid.org/0000-0001-8768-078X; http://lattes.cnpq.br/1507503376593169; Bacelos, Marcelo Silveira; https://orcid.org/0000000208386839; http://lattes.cnpq.br/3741207242086712; Asano, Patricia Teixeira Leite; https://orcid.org/0000-0003-2410-3621; http://lattes.cnpq.br/5742286307682505; Castro, Eustaquio Vinicius Ribeiro de; https://orcid.org/0000-0002-7888-8076; http://lattes.cnpq.br/1055263403980509
Oily effluents are generated in many industrial processes, such as metallurgy, oil refining, petrochemicals, food industries, paint, leather and metal finishing. The improper disposal of these effluents compromises water resources due to the low degradability of the oil. In this context, there is a search for more efficient and economically viable treatment methods. In this research, it was investigated the use of electrofloculation in the treatment of a synthetic oily emulsion with an initial concentration of 200 mg/L in a monitored bench. An experiment design of 32 was implemented with the distance between electrodes fixed at 2 cm to analyze the effects of the factors. The effects of retention time (24, 30 and 36 min) and polarity inversion time (10, 20 and 30 s) were evaluated in relation to electricity consumption and the percentage of removal of oil and grease content, chemical oxygen demand and turbidity. From the experimental conditions, %TOG was achieved between 69.17 and 91.46 %, %COD between 92.80 and 96.25 %, %Turb between 99.23 and 99.79 % and Cen between 4.193 and 7.210 kW.h/m3 . The highest oil removal efficiency was 91.46 % in the retention time of 36 min and in the polarity inversion time of 30 s. In this condition, the energy consumption was approximately 6 kW.h/m3 . The statistical models were satisfactory to predict test results with experimental conditions in the investigated range. The pH and temperature of the final effluent attended to the current environmental legislation. The aluminum concentration in the effluent was higher than is allowed by legislation, varying between 28.2 and 66 mg/L at pH 2 and between 2.6 and 8.8 mg/L at pH 7. The results obtained allowed conclude that the electroflocculation technique was efficient for the treatment of oily effluents.
Estudo da aeração e agitação na produção de celulases por Trichoderma Koningii
(Universidade Federal do Espírito Santo, 2023-12-06) Santos, Patricia Alves dos; Pinheiro, Iara Rebouças; https://orcid.org/0000-0002-3816-2940; Pinotti, Laura Marina; https://orcid.org/0000000250126811; http://lattes.cnpq.br/5616576281329159; https://orcid.org/0000-0002-5885-6843; Bacelos, Marcelo Silveira ; Jesus, Helenice Silva de
Cellulases are enzymes capable of hydrolyzing cellulose, the most abundant biopolymer in nature. Currently, the alcohol industry has been paying special attention to cellulases, as the hydrolysis of cellulose results in sugars that can be fermented into second-generation ethanol. However, the cost of cellulase production in the bioethanol production process can represent around 40% of the total cost. Therefore, it becomes imperative to seek alternatives to make the cost of cellulase production more viable.In enzymatic production, it is possible to investigate different substrates as well as operational conditions that maximize enzymatic production. The objective of this work was to select a substrate (sugarcane bagasse, wheat bran, coconut fiber, coffee powder, sugarcane bagasse + wheat bran) in a shaker that maximizes cellulase production from the fungus Trichoderma koningii. After optimizing this medium in a bioreactor by changing different agitation conditions (200 and 400 rpm) and aeration rates (0.5 and 1.5 vvm), and consequently finding the volumetric oxygen transfer coefficient (KLa), as oxygen is important in the cellulase production process. Subsequently, partial purification/concentration was carried out by fractionated precipitation with ammonium sulfate and organic solvent.The results show that coffee powder is the substrate that presented the maximum enzymatic activity (0.182 ± 0.034 UI/mL) in 72 hours of submerged cultivation in a shaker. In the bioreactor using coffee powder, the maximum enzymatic production was obtained under the conditions of 200 rpm and 1.5 vvm (0.392±0.004 UI/mL). The KLa values increase with the increase in agitation and aeration, reaching the maximum KLa value of 350.26 h-1. However, this increase did not interfere with cellulase production. In the partial purification process by fractionated precipitation with ammonium sulfate, a maximum yield of 10.69% and a purification factor of 1.78 were obtained. Regarding the purification step with organic solvent, the maximum yield achieved was 35.68% with a purification factor of 2.34
Investigação do leito de jorro como reator em potencial de pirólise de partículas cartonadas
(Universidade Federal do Espírito Santo, 2013-08-16) Marques, Ícaro Ibrahim Dias de Rodrigues; Bacelos, Marcelo Silveira; Arrieche, Leonardo da Silva; Lira, Taisa Shimosakai de; Neves, Fernando Luiz
Currently, pyrolysis has received special attention because of its potential application in areas that constitute challenges of the contemporary world, among which stand out the need for renewable energy production and the issue of solid waste management. Among the modern solid wastes, the post-consumer carton packaging highlights due to the high value-added of the primary products (aluminum and paraffin, obtained from its pyrolysis), and coal presenting high calorific value that can be used as fuel to increase the energy efficiency of the process. For presenting good gas-solid contact, high rates of heat and mass transfer and low particle segregation, the conical spouted bed arises as an efficient alternative for the pyrolysis of carton packaging. In this context, in an attempt to use conical spouted beds (CSBs) as a pyrolysis reactor, this present research aims at analyzing the carton particles fluid dynamics in CSBs. To achieve this goal, the fluid dynamics behavior of carton disks mixtures with particles of different specific masses, namely, polyethylene and sand, was investigated. Experimental data of bed pressure drop as a function of air velocity were obtained and analyzed. The operating conditions employed in the conical spouted bed were simulated by CFD technique. For beds composed of polyethylene and carton disks in a range of mass proportion of 20 and 50% carton disk, the analyses established in this research show that the spouting regime is established. For beds comprise mixtures with 5 and 10% carton disk (in mass) stable spouting regime was achieved. At the set of operating conditions, the Eulerian Granular Multiphase Model applied with Syamlal-O‟Brien drag model can qualitatively predict the typical fluid dynamics behavior of a conical spouted bed operating with mixtures of non-spherical particles. An analysis of reuse of the carton packaging via pyrolysis, from the energy and environmental points of view, shows that a large amount of bauxite and energy can be saved due to aluminum which is recovered in the process.
Modelagem da zona de cremagem de uma mistura óleo/água via CFD
(Universidade Federal do Espírito Santo, 2018-08-23) Deoclecio, Lucas Henrique Pagoto; Ribeiro, Daniel da Cunha; Meneguelo, Ana Paula; Ropelato, Karolline; Bacelos, Marcelo Silveira
Gravitational separators of dispersed mixtures of two liquids are present in many industry areas. However, the separation dynamics prediction of these equipment is complex, since it involves the concomitant and of mutual influence (by means of the droplet size distribution (DSD)) mechanisms of creaming (or sedimentation) and coalescence. Therefore, it is important to know the phenomena and the models available for their representation before the model implementation. The objective of this dissertation is to model, through Computational Fluid Dynamics (CFD), the laminar creaming zone of a batch gravitational separation in the Stokes regime. For this, the numerical results (using Ansys Fluent® 15.0 and 18.2) were compared with the experimental results of Jeelani, Hosig and Windhab (2005). To model the influence of the dispersed phase volume fraction on the creaming rate, the Schiller and Naumann drag model (1935) was used with the Richardson and Zaki (1954) drag modifier. The initial DSD was discretized with the Gauss-Legendre Quadrature and the new droplets size born from the coalescence process was estimated using the Wang and Davis (1996) model. Both the DSD representation and the drag models were suitable to model the separation process; however, the determination of the creaming zone limits was shown to be a relevant factor, especially in relation to the determination of the coalescence interface, which seems to be a function of the droplets packaging factor. The coalescence models evaluated were constant coalescing efficiency, critical approach velocity and film drainage time of a deformable drop with partially mobile interface. The three models presented similar results in the modeled flow regime; however, the film drainage model was used with its standard coefficient and did not need to be calibrated. This is because this model is more complete because, besides the relative velocity between the droplets it takes into account the phases viscosities and the surface tension, and the droplets diameter. The coalescence models were calibrated for an experimental condition and then employed with the same fitting parameter for other experiments with different DSD and volume fraction, suggesting the models fitting parameters are function of the liquids properties only. The maximum error between the experimental and numerical creaming and coalescence positions was 5.03%. In addition, the phases volume fraction profile was also estimated with reasonable accuracy by the numerical models.
Otimização estrutural para o processamento de gás natural empregando diferentes técnicas de condensação
(Universidade Federal do Espírito Santo, 2018-03-26) Amaral Junior, Samuel Mathias do; Meneguelo, Ana Paula; Bacelos, Marcelo Silveira; Soares, Vinicius Barroso; Arrieche, Leonardo da Silva
Condensation mechanisms involving gas expansion or heat removal through mechanical refrigeration circuit can be combined to increase the recovery efficiency of natural gas liquid fractions (NGL). To evaluate the flexibilization strategies of flowcharts involving natural gas processing, different process arrangements simulations are performed: Turbo-Expander (TE), self-cooling (Joule-Thomson - JT) and propane refrigerant circuit (RM). Simulations are performed in Aspen Hysys © in steady state, utilizing Peng-Robinson package to predict state variables and phase envelopes. Gas compositions feeds in a range of 5.5 to 11.2% C3 + are applied. For feed mixtures with medium composition and rich in C3 + , the TERM process presents the best economic performance, while for feed mixtures with poor composition in C3 + , the TERM, TE and JTRM processes present similar profitability, except JT. Strategically, for higher LPG production, TERM should be chosen. If the main demand is dry gas (use in thermoelectric plants), the most suitable process is the JT. Following the methane, ethane, propane and butane specification limits on gas products, for all mixtures the TERM and TE processes meet the regulatory standard required by the Brazilian regulatory agency (ANP), except for JT and JTMR.
POTENCIAL ENERGÉTICO DE RECUPERAÇÃO DE ALUMÍNIO DO COMPÓSITO PEBD/Al VIA PIRÓLISE: SEGREGAÇÃO EM LEITO DE JORRO
(Universidade Federal do Espírito Santo, 2020-03-26) Mantegazini, Diunay Zuliani; Bacelos, Marcelo Silveira; https://orcid.org/0000000208386839; http://lattes.cnpq.br/3741207242086712; https://orcid.org/0000000306065991; http://lattes.cnpq.br/; Lira, Taisa Shimosakai de; https://orcid.org/000000022690242X; http://lattes.cnpq.br/8699243861996813; Santos, Kassia Graciele dos; https://orcid.org/; http://lattes.cnpq.br/
Among the carton packages waste recovery processes, pyrolysis is reported as a sustainable, clean and innovative technology. Its use makes it possible to obtain products with high added value, such as paraffinic oils and aluminum ingots, in addition to co
Produção de bio-óleo a partir da pirólise de casca de coco em leito fixo
(Universidade Federal do Espírito Santo, 2018-03-23) Agrizzi, Tiago; Xavier, Thiago Padovani; Lira, Taisa Shimosakai de; Santos, Kássia Graciele dos; Bacelos, Marcelo Silveira
The exploitation of energy resources is fundamental for the economic development of the countries, as the diversified energy matrix guarantees internal supply and mitigates the dependence on energy imports. About 81% of the world's energy demand comes from fossil fuels, which will be a scarce source in the future, and its exploitation will lead to several environmental problems. In view of this, the exploitation of biomass as a renewable energy source is highlighted. In this context, pyrolysis presents like a technology with potential for the conversion of biomass into energy products. Thus, a study of the behavior of the yield of the products formed in the conventional pyrolysis of the green coconut shell in a fixed-bed reactor was carried out from a factorial design 32. In the first stage, the biomass was characterized by the lignocellulosic composition, of the immediate analysis, elemental analysis, X-ray fluorescence and infrared vibrational spectroscopy. In the second stage, the thermal degradation kinetics of the coconut shell were evaluated from the thermogravimetric analyzes, the kinetic models available in the literature and the conventional pyrolysis was performed in a fixed bed reactor. Finally, the identification of the compounds in the bio-oil from pyrolysis was done by gas chromatography coupled to mass spectrometry detector. The calorific value of coconut husk, of 18.01 MJ/kg, 17.3 MJ/kg and 17.93 MJ/kg, was similar using different methodologies. The coconut shell has exploration potential in the generation of thermal energy. The isoconversion kinetic models of Ozawa, Starink and K-A-S were representative for the process. The activation energy found for coconut shell through kinetic models was between 75.95 and 84.51 kJ/mol. The temperature and particle diameter influenced the yield of conventional pyrolysis products in a fixed bed reactor. The maximization of the yield of the bio-oil, 49.45%, was obtained in run 7 with a temperature of 773.15K and an equivalent particle diameter of 2.394 mm. The characterization of the organic fraction of the bio-oil presented the class of the phenols mainly, that can be explored in the chemical and pharmaceutical industry. Coconut shell pyrolysis is an alternative for the exploitation of this agricultural residue.
Rota de conversão de resíduos poliolefínicos em combustíveis : simulação e previsão do índice de mistura em reatores de leito de jorro
(Universidade Federal do Espírito Santo, 2025-02-24) Louvem, Renata Falqueto; Ribeiro, Daniel da Cunha ; https://orcid.org/0000-0003-3690-1938; http://lattes.cnpq.br/8563308324482367; Bacelos, Marcelo Silveira ; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; https://orcid.org/0009-0009-9292-7586; https://orcid.org/0009-0009-9292-7586; Santos, Kassia Graciele dos ; https://orcid.org/0000-0001-7452-6900; http://lattes.cnpq.br/9680475824447820; Siqueira, Renato do Nascimento ; https://orcid.org/0000-0002-8397-8180; http://lattes.cnpq.br/9791817633014124
Pyrolysis in spouted bed reactors with mixtures of polyethylene/aluminum composite particles (LDPE/Al) and sand promotes the waste valorization route for fuel production. However, unstable regimes caused by mixtures of particles with different sizes and specific masses can compromise thermal conversion in the reactor. To contribute to the carton waste management route, this work aims to validate gas-solid flow model in beds composed of sand and composite mixtures through experimental data from the literature. The 2D Euler-Euler granular model is tested with particle mixtures at 30% and 50% composite concentrations and diameter ratios of 1.39 and 2.54. The simulation can predict stable conditions and segregation levels of Mantegazini et al. (2021) and is consistent with experimental data on glass spheres reported by San José et al. (1994). The model can determine the mixing index (Im) of the bed in spouting and collapse regimes with an error of less than 10%. The results indicated that decreasing the diameter ratio and composite concentration in the bed promotes more homogeneous mixtures with Im values close to 1. This research contributes to the fuel production route, in addition to enhancing the valorization and management of solid carton-based waste
Rotas de aproveitamento tecnológico de resíduo orgânico agrícola : casca de coco, casca de cacau e casca de café : destinadas à geração de energia
(Universidade Federal do Espírito Santo, 2014-03-06) Batista, Renato Rocha; Chaves, Gisele de Lorena Diniz; Arrieche, Leonardo da Silva; Bacelos, Marcelo Silveira; Lira, Taisa Shimosakai de; Sartori, Dermeval José Mazzini
The availability of agricultural waste for bioenergy generation come to propose the recent interest by agroenergy sector. For this goal, this dissertation show a bibliografic study for waste characterization of cocoa bark, coconut bark and coffee bark in according to bioenergy technologies: anaerobic digestion, pyrolisys and direct combustion. Its made analysis of technology route possibilities for transform the energy potencial from fruit waste composition in electric energy. The objective its towards the structural synthesis of chemical process by problem representation with process state trees. From the combination of elements of study: fruit waste, biomass processing technology and chemical conversion technologies; its proposed the possibilities of technology routes for elaborate the branches of state trees. The step of structural optimization its based in applied the heuristics method towards the syntesys problem. Thus, its selected the most promised technology route of energetic use of each waste. As a result, the anaerobic digestion in batch reactor was the better option for cocoa bark. For a coconut bark, the chemistry route more adequated was the direct combustion, realized in boiled fixed grid; and for a coffee bark, the thermochemical pyrolysis conversion preceded by pelletization compactation showed more promised. As contribution from this work of dissertation stands out the possibility of energetic valorization of fruit waste untill then considered useless for energetic sector. The problem representation by systematic of state trees and after applied solution by heuristics rules show the originality from this proposed work.
Segregação de misturas binárias de areia e compósito PEBD/Al em leito fluidizado para pirólise rápida de resíduos cartonados
(Universidade Federal do Espírito Santo, 2020-03-23) Santos, Antonio Carlos Oliveira; Bacelos, Marcelo Silveira; https://orcid.org/0000000208386839; http://lattes.cnpq.br/3741207242086712; https://orcid.org/0000-0002-3585-4984; http://lattes.cnpq.br/7348798164399035; Porto, Paulo Sérgio da Silva; https://orcid.org/0000000264867813; http://lattes.cnpq.br/7140925853660088; Arrieche, Leonardo da Silva; https://orcid.org/0000-0002-4606-6019; http://lattes.cnpq.br/7737476090013576
With the accelerated population growth experienced today, solid waste generation is increasing. Aiming at a better energy use, thermo-chemical routes for waste treatment are being sought. In the carton packaging waste sector, pyrolysis is the only route that allows the recovery of aluminum on an industrial scale - due to the devolatization of polyethylene. The fluidized bed reactor is an alternative for rapid pyrolysis of the polyethylene and aluminum composite (LDPE/Al). However, the use of a bed composed of binary mixture of sand and composite polyethylene and aluminum, can generate segregation of particles. Particulate segregation can cause defluidization of the bed and reduce the heat transfer rate and compromise the recovery of aluminum via LDPE/Al pyrolysis. To evaluate the segregation of binary mixtures of sand and LDPE/Al, experiments were conducted in a cylindrical column of 10 cm in diameter and 17 cm in height. The bed was composed of mixtures of sand particles with a diameter of 0.45 mm and LDPE/AL with a range of 0.3 to 2.85 mm. Thus, the objective of this study was to perform a planning of factor 33 experiments, with three central points, to evaluate the effect of the mixing mass fraction factors (XC% w/w), air velocity (V/Vmf) and sand particle diameter ratio and LDPE/AL (dC/dS) on the mixing index (IM). The composite ratios in the mixture were 10 to 30% w/w. Under the investigated conditions, air velocity in a range of 10 to 40% above the minimum fluidization was employed. The use of the planning of experiments made it possible to adjust a statistical model to predict the mixing index. The statistical analysis of the data revealed that only the factors dC/dS and V/Vmf had an effect on IM. The optimal operational conditions (with IM 1) were achieved with values of 0.667 of composite and sand diameter ratio, 10% of air velocity and 15% w/w of composite mass fraction. The statistical model obtained was adequate to predict the values of the mixture index with an error lower than 15%. With the low levels of segregation achieved by the bed in the optimal operational conditions, this contact system can be indicated for the pyrolysis of LDPE/Al, thus allowing the recovery of aluminum.
Simulação computacional do efeito da turbulência na hidrodinâmica de misturadores estáticos Kenics® aplicados à fotocatálise
(Universidade Federal do Espírito Santo, 2024-11-13) Schneider, Bruno de Oliveira; Xavier, Thiago Padovani; https://orcid.org/0000-0001-7148-9921; http://lattes.cnpq.br/8669754182140698; Lira, Taisa Shimosakai de ; https://orcid.org/0000-0002-2690-242X; http://lattes.cnpq.br/8699243861996813; https://orcid.org/0009-0005-2273-2266; http://lattes.cnpq.br/7397231442316912; Bacelos, Marcelo Silveira; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; Santos, Kassia Graciele dos ; https://orcid.org/ 0000-0001-7452-6900; http://lattes.cnpq.br/9680475824447820
The treatment of industrial effluents can be considered an essential factor for sustainable development. Among the advanced oxidative processes (AOPs) applied, heterogeneous photocatalysis stands out due to the possibility of using solar energy and because it occurs at ambient pressure and temperature. Its large-scale application depends on improving the performance of photocatalytic reactors, with the compound parabolic collector reactor being one of the most promising. In this context, the use of static mixers has emerged as an alternative to improve mixing parameters and increase the rate of pollutant degradation. Although there are studies evaluating the main commercial mixers or geometries developed by the author, there is a lack of analysis of the hydrodynamic effect of using mixers in heterogeneous photocatalysis processes. The aim of this work was to numerically evaluate the effect of static mixers on the hydrodynamics of the photocatalytic process in a compound parabolic trough reactor. To do this, the flow inside the reactor was numerically simulated using Ansys Fluent® software for Reynolds numbers of 4,500 and 30,000. The contour plots and current lines of the normalized axial velocity along the tube and in different sections of the mixer were analyzed. The pressure drop resulting from the use of mixers was also evaluated. The results showed that the static mixer promoted the formation of vortices in different regions of the tube, an increase in the velocity gradient and turbulence in the flow. In addition, the geometry of the mixer favored the direction of the fluid towards the edge of the tube, a region that is most affected by radiation. These phenomena contribute to a better dispersion of the catalyst and the effluent in this region, which favors the heterogeneous photocatalytic reaction. Increasing the Reynolds number from 4500 to 30000 contributed to the formation of well-defined vortices, a reduction of the vortices, a reduction in backflow and an increase in higher velocity zones. Therefore, there was a positive effect on the hydrodynamic performance of the reactor
Síntese e análise do processo de secagem artificial de amêndoas de cacau
(Universidade Federal do Espírito Santo, 2015-09-23) Jesus, Patrick Araujo de; Bacelos, Marcelo Silveira; Arrieche, Leonardo da Silva; Ferreira, Margarete Martins Pereira; Lira, Taisa Shimosakai de
The thermal drying is present in the processing of raw materials for various industries such as petrochemical, pulp, agricultural, pharmaceutical and food stage. Often is conducted at low energy efficiency. However, studies for the classification of convective dryers through the heuristic method has been frequently discussed. In this sense, we propose to study the drying of Cocoa beans to be a very important regional product to northern Espírito Santo state, using a fixed bed dryer, typically used for drying raw materials of regional interest sensitive to breakage and excessive temperature. The work steps involve the establishment of the synthesis problem, determination of viable structure for the drying process, recognition and use of experimental unit, sample preparation, driving tests, determination of properties, analysis of the drying experiments, analysis of the experimental data and process performance. Hopefully, with this study, the classification of the best dryer for the product to be dried in the process of convective drying, so that we can analyze not only the kinetics of drying, moisture profiles, speed, temperature, shrinkage material, analysis of energy efficiency, but also predict the evolution of form and the consequent degradation of his physical integrity, thereby contributing to the scientific evolution of drying processes, through convection, based on fundamental knowledge of transport phenomena, and process control.

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