Mestrado em Energia
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- ItemAvaliação da eficácia de um reator retangular, contínuo, com eletrodos em formato de chicanas no tratamento de efluentes oleosos por eletrocoagulação(Universidade Federal do Espírito Santo, 2024-10-29) Leite, Daniela Luz; Andrade, George Ricardo Santana; https://orcid.org/0000-0002-1772-9477; Porto, Paulo Sérgio da Silva; https://orcid.org/0000-0002-6486-7813; Faria, Rochkhudson Batista de; Pinto, Luiz Antônio de AlmeidaOily waters from various industrial sectors are effluents containing millions of liters of oil-in-water (O/W) emulsions, requiring prior treatment before disposal. Research on electrocoagulation (EC) to recover oily effluents has been highlighted. Electrolysis, a non-spontaneous reaction that releases metal into the medium, decomposes the synthetic emulsion, resulting in the formation of flakes in the medium. The flakes integrated with the gas bubbles culminate in the separation of the oil and the obtaining of the treated effluent. This research explored the rectangular geometry, applied to an EC reactor, in the search for an efficient and rapid recovery of emulsified oil in water. The influence of the volumetric flow rate and the polarity inversion time in this process were evaluated. The dependent variables include turbidity, pH, aluminum (Al) concentration, residual oil content and zeta potential. The rectangular reactor was equipped with Al electrodes arranged in the form of baffles, connected by a polarity inverter, operating in continuous mode. The best results were obtained using 2.58 mL/s in the inlet flow rate and 20 s of polarity inversion time, achieving 95.62% oil removal and 97.87% turbidity removal. The highest energy efficiency was obtained using 4 mL/s and 20 s of the parameters recently mentioned, obtaining 89.86% oil removal and 95.70% turbidity removal. The zeta potential analysis showed that the EC alters the stability of the emulsion. The pH remained within the legal requirements throughout all experiments. The wear of the plates was minimal, stipulating that their reuse can be implemented. Complementary tests indicated that the use of perforated electrodes increases the efficiency of contaminant removal, as well as indicating that the reuse of electrodes for twice the time reduced the aluminum concentration at the reactor outlet. Despite this, in all experiments the amount of aluminum obtained was higher than the current standard, indicating the need to add another step in this process, in order to retain Al3+ ions.
- ItemValorização dos resíduos de café para obtenção do biogás(Universidade Federal do Espírito Santo, 2024-09-17) Reis, Thiago Medeiros dos; Lira, Taisa Shimosakai de ; https://orcid.org/0000-0002-2690-242X; http://lattes.cnpq.br/8699243861996813; Pinotti, Laura Marina ; https://orcid.org/0000-0002-5012-6811; http://lattes.cnpq.br/5616576281329159; https://orcid.org/0009-0009-3594-2309; http://lattes.cnpq.br/2591297358528145; Xavier, Thiago Padovani ; https://orcid.org/0000-0001-7148-9921; http://lattes.cnpq.br/8669754182140698; Vieira, Marcelo Fernandes ; https://orcid.org/0000-0001-7290-8569; http://lattes.cnpq.br/5654735215017528Coffee The coffee production in Espírito Santo plays a crucial role in the local economy, being fundamental for the agricultural and financial development of the region. As Brazil's second-largest coffee producer, the state contributes over 30% of the national production, with significant outputs of both Arabica and Conilon. The by products generated, such as coffee grounds and husks, represent a valuable opportunity for energy production. However, the challenge lies in maximizing the utilization of these by-products, which are notable not only for their quantity but also for their rich composition of organic matter and lipids, essential elements for methane production. The valorization of these residues through anaerobic digestion is promising, offering a sustainable disposal method and generating useful by-products, such as biogas for electricity production and organic fertilizer. However, anaerobic digestion faces challenges related to nutrient balance, composition, and complexity of high molecular weight organic molecules. One way to address these issues is by pre treating the organic matter to increase biodegradability and bioavailability of the molecules and performing codigestion to balance nutrients. In this context, this study assessed the biochemical potential of methane (BMP) from domestic coffee grounds (both treated and untreated) and industrial coffee husks (both treated and untreated) in combination with food waste (codigestion). Sludge from a wastewater treatment plant (WWTP) was used as the inoculum. Duplicate batch anaerobic reactors (250 mL) were fed with substrates in different proportions, using a substrate/inoculum ratio of 1. BMP tests were conducted on average for 20 days at mesophilic temperature (35±2 °C). The highest BMP levels were detected with 50% treated coffee grounds (400 NmL/gSV), 50% treated coffee husks (344 NmL/gSV), and 100% food waste (600 NmL/gSV). On the other hand, 100% coffee grounds or coffee husks showed low BMP percentages (88 NmL/gSV) and (186 NmL/gSV) respectively, due to low carbon/nitrogen ratios and pH outside the ideal range. These results indicate that coffee residues have potential for energy recovery through anaerobic digestion (AD), highlighting AD as a promising alternative for the valorization of these residues
- ItemInfluência do potencial da Estruvita (MgNH4PO4.6H2O) sintetizada em reator air-lift no cultivo de microalga Nannochloropsis Oculata(Universidade Federal do Espírito Santo, 2023-12-14) Bento, Nícholas Alexandre Berger; Cotta, Aloísio José Bueno; https://orcid.org/0000-0002-7084-0705; http://lattes.cnpq.br/3298545143757892; Porto, Paulo Sérgio da Silva; https://orcid.org/0000-0002-6486-7813; http://lattes.cnpq.br/7140925853660088; https://orcid.org/0009-0004-4082-2751; http://lattes.cnpq.br/9647502968528308; Pinotti, Laura Marina; https://orcid.org/0000-0002-5012-6811; http://lattes.cnpq.br/5616576281329159; Duarte Filho, Paulo Fernando Marques; https://orcid.org/0000-0003-1423-672X; http://lattes.cnpq.br/2725334713449327This study investigated the nutritional potential of struvite (MgNH4PO4·6H2O), a fertilizer composed of magnesium, ammonium, and phosphate, obtained synthetically and from an industrial effluent. In addition to contributing to the recovery of water bodies by reducing concentrations of ammonium and phosphate, and preventing eutrophication, this precipitation technique results in a commercially valuable product due to the growing demand for fertilizers. The objective of the study was to evaluate the nutritional potential of struvite synthesized in an air-lift reactor in the cultivation of microalgae, based on determining the most efficient and economically viable struvite precipitation condition using synthetic effluent. Variations in molar ratios (without excess Mg; 25% and 50% excess Mg) and air agitation velocities (3, 4.5, and 6 L.min1 ) in the fluidized bed, as well as reaction supersaturation based on ammonium concentration (125, 250, and 375 mg.mL -1 ), were analyzed. The evaluated responses included the removal of ammonium, phosphate, and magnesium, as well as struvite precipitation and the content of precipitate formation. He results indicate a 95% precipitate yield, highlighting the influence of ammonium concentration on the removals of Mg2+, NH4 + , and PO4 3- . In Nannochloropsis oculata cultures, conducted with 'Guillard medium,' 'Guillard enriched with synthetic struvite,' 'Guillard enriched with industrial struvite,' and 'only struvite,' cultivation with only struvite demonstrated potential as a nutritional source, achieving a cell density of 2.57x107 cells.mL-1 . The comparison between synthetically produced struvite and struvite from an industrial effluent revealed similar cellular growth behavior, suggesting equivalence in nutritional potential. It is concluded that, under the studied experimental conditions, the results are satisfactory, allowing to production of a fertilizer by the used air-lift reactor and effective application of struvite as a nutritional source in the cultivation of the microalga Nannochloropsis oculata.
- ItemO gás natural como fonte geradora na diversificação da matriz elétrica brasileira(Universidade Federal do Espírito Santo, 2023-04-05) Barcelos, Mariana Vieira; Meneguelo, Ana Paula; https://orcid.org/0000000262241139; http://lattes.cnpq.br/1800610548349937; https://orcid.org/0000-0002-6315-861X; http://lattes.cnpq.br/5714462051131187; Santos Junior, Jorge Luiz dos; https://orcid.org/0000-0001-8297-0112; http://lattes.cnpq.br/9167714430259668; Furtado, Andreia Cristina; https://orcid.org/0000-0003-1407-5989; http://lattes.cnpq.br/0969254728157087Energy consumption in the world has been growing annually, which requires an increase in the standard of production and distribution of available energy sources. One of the main energy consumption is linked to the electricity sector, based mainly on fossil fuels such as oil and coal. In Brazil, more than 60% of electricity consumption comes from hydroelectric plants. The little variability of energy sources in the Brazilian electrical matrix can cause an overload in the use of the source, or even generate shortages, which makes it necessary to diversify alternative sources to supply the demand. This occurs in periods of low rainfall, when hydroelectric plants operate with lower capacity than expected and the system becomes unstable. In this sense, it is necessary to use an alternative source of electricity that can work together with the hydroelectric plant and guarantee the stability of electricity generation. In view of this, natural gas presents itself as a good alternative for this replacement, as it is a safe source and less aggressive to the environment than other non-renewable sources. Some countries are already in the process of transitioning from electricity to natural gas, as is the case with China, one of the largest consumers of this source in the world. Thus, this work aims to list the incentives observed in these countries that lead to better development of natural gas in the electricity matrix. For this, the parameters of reserves, production and incentives of natural gas in the Brazilian and world electric matrix were used. Thus, it was possible to observe that Brazil needs to face the challenges of fees and taxes on the use of natural gas in the electricity matrix, in order to generate incentives for greater investments in the sector. In addition, it is observed that the country has great potential for greater production of natural gas, however, it is still necessary to make improvements in infrastructure to support greater volumes of gas produced.
- ItemSÍNTESE E CARACTERIZAÇÃO DE EMULSÕES ÓLEO EM ÁGUA PARA INJEÇÃO EM MEIOS POROSOS(Universidade Federal do Espírito Santo, 2022-12-23) Dias, Leticia Silveira; Guzman, Oldrich Joel Romero; https://orcid.org/0000000157746987; http://lattes.cnpq.br/3981995002595753; https://orcid.org/0000000243255148; http://lattes.cnpq.br/; Meneguelo, Ana Paula; https://orcid.org/0000000262241139; http://lattes.cnpq.br/1800610548349937; Quinones, Danmer Paulino Maza; https://orcid.org/; http://lattes.cnpq.br/abstract