Thermal behavior and kinetics assessment of ethanol/gasoline blends during combustion by thermogravimetric analysis

Quiroga, Luís Carlos Ríos; Balestieri, José Antônio Perrella; Ávila, Ivonete

doi:10.1016/j.applthermaleng.2016.12.051

Cited by 16 publications

(4 citation statements)

References 32 publications

(54 reference statements)

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“…The activation energy for the oxidation of soot is calculated by the differential method. First, the conversion rate (α) of the sample is defined as , where m 0 , m ∞ , m , T , and t represent the mass of sample at the beginning of the reaction, the mass at the end of the reaction, the sample mass at T ( t ), the reaction temperature, and time, respectively.…”

Section: Discussionmentioning

confidence: 99%

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Effect of Different Aging Conditions on the Soot Oxidation by Thermogravimetric Analysis

et al. 2020

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Diesel particulate filter is an effective device to reduce diesel particulate emission. The particles in diesel particulate filter are usually affected by the aging of high-temperature exhaust gas before the regeneration process. In order to investigate the effect of aging conditions on the soot oxidation process, the effect of aging temperature and aging time on the oxidation process of carbon black (Printex-U, PU) and the PU/catalyst/ash mixture are studied by thermogravimetric analysis. The aging PU particles have lower starting temperature, peaking temperature, ending temperature, and activation energy. Compared with the particles without aging, the PU particles with a 400 °C aging temperature and 20 h aging time are able to reduce the activation energy from 191.2 to 158 kJ/mol. Low aging temperatures (200–300 °C) and the catalyst have a certain synergistic effect on the improvement of PU oxidation activity. The PU/CeO2 mixture with a 300 °C aging temperature and 20 h aging time decreases the activation energy from 178.4 to the lowest 113.6 kJ/mol. The addition of CaSO4 in PU particles cannot stop the improvement of its oxidation activity by aging, but it reduces the effect of aging. This work is helpful to reveal the mechanism of aging on PU and the PU/catalyst/ash mixture in air environment.

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Section: Discussionmentioning

confidence: 99%

“…The activation energy for the oxidation of soot is calculated by the differential method. First, the conversion rate (α) of the sample is defined as 38,39 m m m m…”

Section: Experimental Methodmentioning

confidence: 99%

Effect of Different Aging Conditions on the Soot Oxidation by Thermogravimetric Analysis

et al. 2020

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“…In recent years, ethanol has been considered a promising alternative fuel to Brazil, the second-largest producer of this biofuel in the world [1]. The growing commercialization of flex-fuel vehicles, which can operate with any proportion ratio of ethanol and gasoline [2], combined with the favorable climate for the cultivation of sugar cane, the main source of the biofuel extraction in the country, and the mandatory 27% blend in gasoline are the major reasons for the ethanol success in Brazil [3][4][5]. Besides, the country's already existing experience with the fuel production and distribution is notable, once the Brazilian sugar ethanol industry dates back to 1970 due to the pro-alcohol initiative, which was an ethanol incentive program in the market that emerged after the 1970s oil crisis [1,6].…”

Section: Introductionmentioning

confidence: 99%

An evaluation of combustion aspects with different compression ratios, fuel types and injection systems in a single-cylinder research engine

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et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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The growing commercialization of flex-fuel vehicles in Brazil demands the optimization of internal combustion engines for the operation with ethanol (E100) and gasohol (E22), in an attempt to reduce the fuel consumption and minimize the pollutant emissions into the atmosphere. In this sense, this work proposes the study of different volumetric compression ratios in a single-cylinder research engine in order to conclude about its fuel conversion efficiency and, in particular, a more detailed combustion investigation for two of the most common Brazilian fuels. Dynamometric bench tests were performed for distinct compression ratios, injection systems and fuel types, which demanded a specific piston design to meet the requirements for each combustion chamber configuration. The use of ethanol was the most suitable when compared to gasohol, especially at high load conditions, in which was observed a knock tendency for E22 but not for E100, due to its improved physicochemical properties, resulting in enhanced combustion aspects. The proposed methodology proved effective in allowing fuel conversion efficiency gains for the tested fuels, injection systems and piston designs when compared to the engine baseline operation, with up to 6.1% improvement when using the most appropriate compression ratio. Finally, the ethanol direct injection confirmed the potential of this Brazilian biofuel as one of the most promising renewable options for internal combustion engines in current and future sustainable energy directives. Keywords Compression ratio • Internal combustion engine • Fuel conversion efficiency • Ethanol • Flex-fuel Abbreviations ABDC After bottom dead center APMAX Angle of maximum pressure (°) ATDC After top dead center BBDC Before bottom dead center BMEP Brake mean effective pressure (bar) BTDC Before top dead center CA Crank angle CO 2 Carbon dioxide COV Covariance (%) CR Compression ratio DI Direct injection E100

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“…Ethanol is considered a promising alternative fuel because it is derived from biomass via established and new processes, as proved by the evolution from first to third-generation biofuels; it seems to be easy merging its production and use with the existing infrastructure; and it has advantages when compared with conventional fuels. If compared with gasoline, to illustrate, ethanol has a significantly higher octane number and latent heat of evaporation, which improves thermal and volumetric efficiencies and may reduce emissions of pollutants, such as carbon monoxide, exhaust hydrocarbons and fine particulates (AGARWAL, 2007;WESTBROOK, 2013;QUIROGA; BALESTIERI;ÁVILA, 2017).…”

Section: Alternative Fuelsmentioning

confidence: 99%

Lagrangian modeling of droplet evaporation

Pinheiro¹

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Evaporation of liquid droplets in high temperature gas environment is of great importance in many engineering applications. Accurate droplet evaporation predictions are crucial in modeling spray combustion, since it is considered a rate limiting process. For this reason, the present dissertation aims are, first, to implement and validate Lagrangian droplet evaporation models that are usually used in spray calculations, including equilibrium and non-equilibrium formulations, and, second, to use these models to pursue a deeper insight on the physical phenomena that may be involved in droplet evaporation processes. In order to validate and assess these theoretical model predictions, an in-house code was developed and diameter evolution results from the numerical simulations are compared to experimental data. First, the model performance is evaluated for water in a case of low evaporation rate and, then, it is evaluated for n-heptane in moderate and high evaporation rates using recent experimental data acquired with a new technique. The Abramzon-Sirignano model is the only one which does not overestimate the evaporation rate for any ambient condition tested, when compared with experimental rate. From the results, it is also revealed that, when a correction factor for energy transfer reduction due to evaporation is incorporated in the classical evaporation model, the predictions from this model and the nonequilibrium one cannot be differentiated, even if the initial droplet diameter is small. Furthermore, the incorporation of natural and forced convection effects on the droplet evaporation rate, by using an empirical correlation, is investigated, showing that including the Grashof number into the Ranz-Marshall correlation actually overestimates the evaporation rate for atmospheric pressure. Finally, the effects of ambient conditions on ethanol evaporation are investigated. Under ambient temperatures higher than the threshold temperature, the evaporation rate is enhanced with the increase of ambient pressure, contrary to what happens for cases when the ambient temperature is lower than the threshold temperature.

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Thermal behavior and kinetics assessment of ethanol/gasoline blends during combustion by thermogravimetric analysis

Cited by 16 publications

References 32 publications

Effect of Different Aging Conditions on the Soot Oxidation by Thermogravimetric Analysis

Effect of Different Aging Conditions on the Soot Oxidation by Thermogravimetric Analysis

An evaluation of combustion aspects with different compression ratios, fuel types and injection systems in a single-cylinder research engine

Lagrangian modeling of droplet evaporation

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