Navegando por Palavras-chave "Gasoline"
Agora exibindo 1 - 4 de 4
Resultados por página
Opções de Ordenação
- ItemAcesso aberto (Open Access)Avaliação de parâmetros de combustíveis automotivos(Universidade Federal de São Paulo, 2022-12-16) Jordan, Vitor Junqueira de Souza [UNIFESP]; Barbosa, Lúcio Leonel [UNIFESP]; http://lattes.cnpq.br/4184066856833642; Universidade Federal de São Paulo (UNIFESP)Os combustíveis derivados do petróleo como a gasolina e o diesel são parte integrante do dia a dia da população brasileira e mundial, principalmente para o uso em automóveis. Este atual cenário evidencia a necessidade da realização de fiscalizações e análises físico químicas sobre a procedência e o índice de qualidade desses combustíveis, verificando assim se estão em conformidades da ANP, pois a adulteração dos mesmos pode causar sérios riscos aos motores dos automóveis devido a queima do combustível de forma incorreta, além dos prejuízos ambientais com as emissões de monóxido de carbono que é um composto prejudicial a saúde. Neste trabalho, foram feitas análises com as caracterizações da massa específica, viscosidade cinemática, cor e aspecto em amostras do diesel S10 de dois postos de abastecimento do município de Santos/SP, além de duas amostras gasolina que tiveram suas massas específicas analisadas. Ademais a variação da viscosidade cinemática foi analisada por meio da adulteração de Diesel com diferentes percentuais volumétricos de óleo de soja e querosene, além da própria gasolina ser testada como adulterante do diesel em temperatura de 40°C graus. Com relação aos resultados das quatro amostras um e dois de diesel S10 e gasolina comum, duas das delas estavam dentro das conformidades exigidas pela ANP, a amostra dois de diesel apresentou não conformidade, e a amostra dois de gasolina também não apresentou conformidade. Pode-se concluir que em relação à viscosidade cinemática a mesma apresentou valores dentro das conformidades, além disso, foi possível observar uma taxa de variação que estabeleceu uma relação inversa entre temperatura e viscosidade pois no procedimento experimental notou-se que quando a temperatura do fluido aumentava, a sua viscosidade tendia a diminuir, notou-se também que mesmos com altos percentuais de adulteração de querosene, o óleo diesel ainda se mantinha dentro das conformidades da ANP. Quanto à adulteração do diesel S10 com querosene, a viscosidade cinemática variou de 3,6 mm²/s /s até 1,84 mm²/s e em relação à adulteração do diesel S10 com óleo de soja, a viscosidade cinemática das misturas variaram entre 3,05 mm²/s e 29,14 mm²/s , estabelecendo assim uma variação de 1,52 mm²/s para o querosene e 26,09 mm²/s para óleo de soja.
- ItemSomente MetadadadosDenatured ethanol release into gasoline residuals, Part 2: Fate and transport(Elsevier B.V., 2013-05-01) Freitas, Juliana G. [UNIFESP]; Barker, James F.; Universidade Federal de São Paulo (UNIFESP); Univ WaterlooWhen denatured ethanol (E95) is spilled in a site with previous gasoline contamination, it modifies the source distribution (Part 1). But it can also impact the transport and fate of hydrocarbons in the groundwater. Ethanol could cause an increase in dissolved concentrations and more persistent plumes due to cosolvency and decreased hydrocarbon biodegradation rates. To investigate these possibilities, two controlled releases were performed: first of E10 (gasoline with 10% ethanol) and one year later of E95 on top of the gasoline. Groundwater concentrations were monitored above and below the water table in multilevel wells. Soil cores and vapor samples were also collected over a period of approximately 400 days. Surprisingly, ethanol transport was very limited; at wells located 23 m downgradient from the mid-point of the release trench, the maximum concentration measured was around 2400 mg/L. After 392 days, only 3% of the ethanol released migrated past 23 m, and no ethanol remained in the source. the processes that caused ethanol loss were likely volatilization, aerobic biodegradation in the unsaturated zone, and anaerobic biodegradation. Evidence that biodegradation was significant in the source zone includes increased CO2 concentrations in the vapor and the presence of biodegradation products (acetate concentrations up to 2300 mg/L). the position of the dissolved hydrocarbon plumes was slightly shifted, but the concentrations and mass flux remained within the same range as before the spill, indicating that cosolvency was not significant. Hydrocarbons in the groundwater were significantly biodegraded, with more than 63% of the mass being removed in 7.5 m, even when ethanol was present in the groundwater. the impacts of ethanol on the hydrocarbon transport and fate were minimal, largely due to the separation of ethanol and hydrocarbons in the source (Part 1). (C) 2013 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosDenatured ethanol, release into gasoline residuals, Part 1: Source behaviour(Elsevier B.V., 2013-05-01) Freitas, Juliana G. [UNIFESP]; Barker, James F.; Universidade Federal de São Paulo (UNIFESP); Univ WaterlooWith the increasing use of ethanol in fuels, it is important to evaluate its fate when released into the environment. While ethanol is less toxic than other organic compounds present in fuels, one of the concerns is the impact ethanol might have on the fate of gasoline hydrocarbons in groundwater. One possible concern is the spill of denatured ethanol (E95: ethanol containing 5% denaturants, usually hydrocarbons) in sites with pre-existing gasoline contamination. in that scenario, ethanol is expected to increase the mobility of the NAPL phase by acting as a cosolvent and decreasing interfacial tension. To evaluate the E95 behaviour and its impacts on pre-existing gasoline, a field test was performed at the CFB-Borden aquifer. Initially gasoline contamination was created releasing 200 L of E10 (gasoline with 10% ethanol) into the unsaturated zone. One year later, 184 L of E95 was released on top of the gasoline contamination. the site was monitored using soil cores, multilevel wells and one glass access tube. At the end of the test, the source zone was excavated and the compounds remaining were quantified. E95 ethanol accumulated and remained within the capillary fringe and unsaturated zone for more than 200 days, despite similar to 1 m oscillations in the water table. the gasoline mobility increased and it was redistributed in the source zone. Gasoline NAPL saturations in the soil increased two fold in the source zone. However, water table oscillations caused a separation between the NAPL and ethanol: NAPL was smeared and remained in deeper positions while ethanol moved upwards following the water table rise. Similarly, the E95 denaturants that initially were within the ethanol-rich phase became separated from ethanol after the water table oscillation, remaining below the ethanol rich zone. the separation between ethanol and hydrocarbons in the source after water table oscillation indicates that ethanol's impact on hydrocarbon residuals is likely limited to early times. (C) 2013 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosReid vapor pressure prediction of automotive gasoline using distillation curves and multivariate calibration(Elsevier Sci Ltd, 2017) Mendes, Gisele; Aleme, Helga Gabriela [UNIFESP]; Barbeira, Paulo J. S.Partial least squares regression (PLS) in conjunction with distillation curves (ASTM D86) were used successfully to predict the vapor pressure of automotive gasoline. The errors obtained in the calibration and validation models (0.71 and 0.69 kPa) were lower than those reported in the literature. In addition, the proposed method is inexpensive, reduces test time and is easy to implement, making it an alternative method for gasoline quality control. It does be possible because the distillation tests are already routinely performed by ANP as one of the evaluation parameter of the automotive gasoline quality. (C) 2016 Elsevier Ltd. All rights reserved.