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Semih Eser - One of the best experts on this subject based on the ideXlab platform.
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Thermal Decomposition of Jet Fuel Model Compounds under Near-Critical and Supercritical Conditions. 1. n-Butylbenzene and n-Butylcyclohexane
Industrial & Engineering Chemistry Research, 1998Co-Authors: Jian Yu, Semih EserAbstract:Thermal decomposition of n-butylbenzene and n-butylcyclohexane was studied under near-critical and supercritical conditions in relation to future jet Fuel thermal stability problems. The reactions of n-butylbenzene and n-butylcyclohexane can be explained by free-radical mechanisms, dominated by side-chain cracking. The major liquid products from n-butylbenzene were styrene and toluene. Toluene was the major product in the far supercritical region while styrene was the dominant product in the low-pressure subcritical region. The main liquid products from n-butylcyclohexane were 1-methylcyclohexene and cyclohexane. The 1-methylcyclohexene was a secondary product which was derived from methylenecyclohexane. This conversion was favored at high pressures. High pressures under supercritical conditions promoted radical addition reactions, leading to the formation of some high-molecular-weight compounds which were not observed under low-pressure conditions. The kinetic data obtained for the thermal decomposition ...
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thermal decomposition of jet Fuel Model compounds under near critical and supercritical conditions 2 decalin and tetralin
Industrial & Engineering Chemistry Research, 1998Co-Authors: Semih EserAbstract:Thermal decomposition of two jet Fuel Model compounds, Decalin and Tetralin, was studied under near-critical and supercritical conditions. Under high-pressure supercritical conditions, the thermal decomposition of both compounds was dominated by isomerization reactions. This is different from the results obtained under low-pressure and high-temperature conditions where cracking reactions (for Decalin) or dehydrogenation reactions (for Tetralin) dominate. The major liquid products from Decalin were spiro[4,5]decane, 1-butylcyclohexene, 1-methylcyclohexene, 1-methylhydrindan, two octalins, and toluene. The cis-decalin was converted to trans-decalin as the reaction proceeded. The main liquid products from Tetralin were 1-methylindan and naphthalene with the former being the dominant product that was favored at high pressures.
Rolf D Reitz - One of the best experts on this subject based on the ideXlab platform.
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development of a skeletal mechanism for diesel surrogate Fuel by using a decoupling methodology
Combustion and Flame, 2015Co-Authors: Yachao Chang, Ming Jia, Yaodong Liu, Maozhao Xie, Hu Wang, Rolf D ReitzAbstract:Abstract A diesel surrogate Fuel Model was developed by including n -decane, iso -octane, methylcyclohexane (MCH), and toluene, which represents the n -paraffins, iso -paraffins, cycloalkanes, and aromatic hydrocarbons in diesel Fuel, respectively. The proportions of the components in the surrogate Model were determined with special focus on reproducing the chemical characteristics of diesel Fuel and less emphasis on its physical characteristics. Then, a decoupling methodology was employed to construct a skeletal oxidation mechanism for the diesel surrogate Model, in which the oxidation of small molecules is described in detail, while extremely simplified mechanisms are used for the oxidation of large molecules. The final skeletal mechanism for the diesel surrogate Fuel consists of 70 species and 220 reactions without considering cross reactions of the Fuel components. The mechanism was extensively validated based on various fundamental experiments for the single components and their mixtures, as well as for practical diesel Fuel under wide operating conditions. The predicted ignition delay in shock tubes and the primary species concentrations in jet stirred reactors, flow reactors, and premixed laminar flames agree with the measurements reasonably well, which confirms that the assumption of neglecting the co-oxidation reactions is reasonable. The flame propagation and extinction characteristics are also well reproduced by the mechanism due to the employment of the detailed mechanism for the low-carbon-number molecules.
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a combustion Model for multi component Fuels using a physical surrogate group chemistry representation psgcr
Combustion and Flame, 2015Co-Authors: Rolf D ReitzAbstract:Abstract A combustion Model to simulate the oxidation of multi-component Fuels has been developed and applied to Model autoignition combustion processes. The Model is called the Physical Surrogate Group Chemistry Representation (PSGCR) method, which combines a multi-component Fuel Model to describe the physical properties of the Fuel with reduced reaction mechanisms to represent the chemistry of the Fuel components. A group of physical surrogate (PS) components are used to describe the Fuel’s physical properties, such as the distillation profile, specific gravity, lower heating value and hydrogen-to-carbon (H/C) ratio. The oxidation processes of the Fuel are Modeled using skeletal reaction mechanisms for a group of chemical surrogate (CS) components that employ generic reactions as well as detailed reaction kinetics. The generic reactions were built to Model unavailable reaction pathways from physical surrogates to the base CS components or their intermediate species. The Model includes the 6 major chemical classes of typical hydrocarbon Fuels, i.e., n-paraffins, iso-paraffins, olefins, naphthenes, aromatics and oxygenates, and 65 representative hydrocarbon components are included in a data base for the physical surrogate components and 43 chemical surrogate components are considered for the group chemistry representation. Six types of generic reaction sets are proposed to Model the oxidation of 15 physical surrogate components that are called extended-CS (chemical surrogate) components. The present generic reactions are Modeled such that the major characteristics of the oxidation process of the Fuel components are included in a consistent manner. The final version of the PSGCR reaction mechanism consists of 264 species and 1292 reactions. Validation of the reaction mechanisms was performed by comparing predicted ignition delay times with experimental measurements and/or predictions from comprehensive mechanisms available in the literature. The Model was also validated against HCCI experimental data of the FACE Fuels. Then the Model was applied to simulate practical diesel Fuel (F76) spray combustion in a constant volume chamber, and the predicted ignition delay times of the surrogate Model Fuel were compared with measured values. The results show that the present PSGCR method captures the combustion characteristics of complex multi-component Fuels, giving reliable performance for combustion predictions, as well as computational efficiency improvements for multi-dimensional CFD simulations through the use of reduced mechanisms.
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surrogate Model development for Fuels for advanced combustion engines
Energy & Fuels, 2011Co-Authors: K Anand, Rolf D Reitz, Bruce G BuntingAbstract:The Fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real Fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate Model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the target Fuel. The present study proposes surrogate Models for the nine Fuels for advanced combustion engines (FACE) that have been developed for studying low-emission, high-efficiency advanced diesel engine concepts. The surrogate compositions for the Fuels are arrived at by simulating their distillation profiles to within a maximum absolute error of ∼4% using a discrete multi-component (DMC) Fuel Model that has been incorporated in the multi-dimensional computational fluid dynamics (CFD) code, KIVA-ERC-CHEMKIN. The simulated surrogate compositions cover the range and measured concen...
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numerical study of Fuel composition effects on low temperature diesel combustion with a discrete multi component vaporization Model
ASME 2009 Internal Combustion Engine Division Spring Technical Conference, 2009Co-Authors: Rolf D ReitzAbstract:A numerical investigation of Fuel composition effects on diesel engine combustion is presented. A new discrete multi-component (DMC) Fuel Model was used to represent the properties and composition of multi-component diesel Fuels. A multi-dimensional CFD code, KIVA-ERC-Chemkin, that is coupled with improved sub-Models and the Chemkin library, was employed for the simulations. A small-bore, high-speed DI diesel engine operating in a low temperature combustion (LTC) regime was simulated with four different diesel Fuels using a 6-component Fuel Model. The oxidation chemistry was calculated using a reduced mechanism for primary reference Fuel, with the reaction rate coefficients adjusted to account for the Cetane number (CN) variation of the Fuels of interest. The major property differences of the Fuels include volatility, viscosity, and autoignitability. The predicted pressure, heat release rate, and emissions are compared with experimental data available in the literature. The results show that the present multi-component Fuel Model performs reliably, and captures the effects of Fuel composition differences on combustion. The emissions trends for the different Fuels were also in good agreement with the corresponding experimental measurements. The results also indicate that, in addition to more realistic predictions of the Fuel physical properties, further improvements of the chemical characteristics of the Fuel components is desirable.Copyright © 2009 by ASME
Ana R Ferreira - One of the best experts on this subject based on the ideXlab platform.
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thiols extraction from jet Fuel assisted by ionic liquids in hollow fibre membrane contactors
Journal of Membrane Science, 2015Co-Authors: Ana R Ferreira, Luisa A Neves, Jorge C Ribeiro, Fernando M Lopes, Joao A P Coutinho, Isabel M Coelhoso, Joao G CrespoAbstract:Abstract This work proposes an alternative technique for the selective extraction of thiols from a “jet-Fuel” Model stream, using the 1-ethyl-3-methylimidazolium triflate ([C 2 mim][CF 3 SO 3 ]) ionic liquid as extractant, in a hollow fibre membrane contactor. Due to the low distribution ratio of the thiol towards the ionic liquid, observed in single extraction, a regeneration step (stripping with vacuum or a sweep gas) was added to the extraction process, in order to maximize the concentration gradient overcoming thermodynamic constraints. The stripping with a sweep gas allowed for a complete regeneration of the ionic liquid producing a jet-Fuel with sulphur content lower than 2 ppm. Since the controlling step of the process is the extraction of thiol from the feed phase to the ionic liquid phase, the increase of the ionic liquid velocity and operating temperature may further enhance the process performance. The results obtained along with the ultra-low sulphur jet-Fuel Model produced prove the high potential of this integrated process as an alternative method for replacing the current expensive desulphurization process.
Joao G Crespo - One of the best experts on this subject based on the ideXlab platform.
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thiols extraction from jet Fuel assisted by ionic liquids in hollow fibre membrane contactors
Journal of Membrane Science, 2015Co-Authors: Ana R Ferreira, Luisa A Neves, Jorge C Ribeiro, Fernando M Lopes, Joao A P Coutinho, Isabel M Coelhoso, Joao G CrespoAbstract:Abstract This work proposes an alternative technique for the selective extraction of thiols from a “jet-Fuel” Model stream, using the 1-ethyl-3-methylimidazolium triflate ([C 2 mim][CF 3 SO 3 ]) ionic liquid as extractant, in a hollow fibre membrane contactor. Due to the low distribution ratio of the thiol towards the ionic liquid, observed in single extraction, a regeneration step (stripping with vacuum or a sweep gas) was added to the extraction process, in order to maximize the concentration gradient overcoming thermodynamic constraints. The stripping with a sweep gas allowed for a complete regeneration of the ionic liquid producing a jet-Fuel with sulphur content lower than 2 ppm. Since the controlling step of the process is the extraction of thiol from the feed phase to the ionic liquid phase, the increase of the ionic liquid velocity and operating temperature may further enhance the process performance. The results obtained along with the ultra-low sulphur jet-Fuel Model produced prove the high potential of this integrated process as an alternative method for replacing the current expensive desulphurization process.
Jian Yu - One of the best experts on this subject based on the ideXlab platform.
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Thermal Decomposition of Jet Fuel Model Compounds under Near-Critical and Supercritical Conditions. 1. n-Butylbenzene and n-Butylcyclohexane
Industrial & Engineering Chemistry Research, 1998Co-Authors: Jian Yu, Semih EserAbstract:Thermal decomposition of n-butylbenzene and n-butylcyclohexane was studied under near-critical and supercritical conditions in relation to future jet Fuel thermal stability problems. The reactions of n-butylbenzene and n-butylcyclohexane can be explained by free-radical mechanisms, dominated by side-chain cracking. The major liquid products from n-butylbenzene were styrene and toluene. Toluene was the major product in the far supercritical region while styrene was the dominant product in the low-pressure subcritical region. The main liquid products from n-butylcyclohexane were 1-methylcyclohexene and cyclohexane. The 1-methylcyclohexene was a secondary product which was derived from methylenecyclohexane. This conversion was favored at high pressures. High pressures under supercritical conditions promoted radical addition reactions, leading to the formation of some high-molecular-weight compounds which were not observed under low-pressure conditions. The kinetic data obtained for the thermal decomposition ...
