The Experts below are selected from a list of 14454 Experts worldwide ranked by ideXlab platform
Faisal S. Alhumaidan - One of the best experts on this subject based on the ideXlab platform.
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changes in asphaltenes during Thermal Cracking of residual oils
Fuel, 2014Co-Authors: Haitham M.s. Lababidi, Hawraa M Sabti, Faisal S. AlhumaidanAbstract:Abstract This study attempts to understand how asphaltene molecules change under Thermal stress. Asphaltene samples were precipitated from three crude oils and their atmospheric residues, vacuum residues, and pitch, using n -heptane. The pitch samples were obtained from the Thermal Cracking of vacuum residues at three operating temperatures (400, 415, and 430 °C) and three reaction times (30, 50, and 60 min). Asphaltene samples were characterized using gel permeation chromatography (GPC), ultraviolet spectroscopy (UV), metal content (Ni and V) analyses, and elemental analysis of C, H, N, and S. The experimental observations suggest that Thermal Cracking conditions influence the structure and the properties of asphaltene. An increase in Cracking severity resulted in a notable decrease in the molecular size of asphaltene; a significant increase in aromaticity; a reduction in the H/S ratio, which indicates the presence of sulfur as a disulfide (–C–S–C–) and not as thiophenol or HS groups; and the concentration of metals in the core of smaller polyaromatic asphaltene molecules.
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Thermal Cracking kinetics of Kuwaiti vacuum residues in Eureka process
Fuel, 2013Co-Authors: Faisal S. Alhumaidan, Haitham M.s. Lababidi, Hassan Al-rabiahAbstract:Abstract This work presents the development of a kinetic model for the Thermal Cracking of vacuum residues in a pilot-scale semi-batch reactor, which simulates the Cracking operation performed in the Eureka process. The vacuum residues were derived from three Kuwaiti crude oils, both conventional and heavy. Experimental data was obtained at three Cracking temperatures (400, 415, and 430 °C) and three reaction times (30, 50, and 60 min). The proposed Thermal Cracking kinetic model is based on the discrete lumping approach. The reaction scheme consisted of five lumps: the four cracked products and residual unconverted oil. The cracked products represent the product slates obtained from the commercial Eureka process, namely, the off-gases ( 538 °C). The analysis of the results revealed that the Thermal Cracking of vacuum residue follows first order kinetics. The proposed model predicted the kinetic parameters for the Thermal Cracking of different residual feedstock and provided a good fit to the experimental data.
Junichi Kubo - One of the best experts on this subject based on the ideXlab platform.
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Radiation effect on the Thermal Cracking of n-hexadecane. 1: Products from radiation-Thermal Cracking
Industrial & Engineering Chemistry Research, 1997Co-Authors: Yosuke Katsumura, Chihiro Matsuura, Kenkichi Ishigure, Junichi KuboAbstract:In order to examine the applicability of radiation technology to hydrocarbon processing, radiation-Thermal Cracking of n-hexadecane was carried out in the liquid and gas phases by introducing cobalt-60 {gamma}-radiation in the temperature range of 300--400 C. The Cracking process was observed to be significantly enhanced in both phases. For example, it was about 100 times faster under a dose rate of around 500 Gy/h at 330 C in the gas phase. The observed product pattern for radiation-Thermal Cracking was the same as that for pure Thermal Cracking, only dependent on the phase. Similar to pure Thermal Cracking, addition products and larger yields of alkanes were observed in the liquid phase, whereas no addition products but larger yields of alkenes were observed in the gas phase. In addition, a large evolution of H{sub 2} due to C-H dissociation by radiation was observed.
Haitham M.s. Lababidi - One of the best experts on this subject based on the ideXlab platform.
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changes in asphaltenes during Thermal Cracking of residual oils
Fuel, 2014Co-Authors: Haitham M.s. Lababidi, Hawraa M Sabti, Faisal S. AlhumaidanAbstract:Abstract This study attempts to understand how asphaltene molecules change under Thermal stress. Asphaltene samples were precipitated from three crude oils and their atmospheric residues, vacuum residues, and pitch, using n -heptane. The pitch samples were obtained from the Thermal Cracking of vacuum residues at three operating temperatures (400, 415, and 430 °C) and three reaction times (30, 50, and 60 min). Asphaltene samples were characterized using gel permeation chromatography (GPC), ultraviolet spectroscopy (UV), metal content (Ni and V) analyses, and elemental analysis of C, H, N, and S. The experimental observations suggest that Thermal Cracking conditions influence the structure and the properties of asphaltene. An increase in Cracking severity resulted in a notable decrease in the molecular size of asphaltene; a significant increase in aromaticity; a reduction in the H/S ratio, which indicates the presence of sulfur as a disulfide (–C–S–C–) and not as thiophenol or HS groups; and the concentration of metals in the core of smaller polyaromatic asphaltene molecules.
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Thermal Cracking kinetics of Kuwaiti vacuum residues in Eureka process
Fuel, 2013Co-Authors: Faisal S. Alhumaidan, Haitham M.s. Lababidi, Hassan Al-rabiahAbstract:Abstract This work presents the development of a kinetic model for the Thermal Cracking of vacuum residues in a pilot-scale semi-batch reactor, which simulates the Cracking operation performed in the Eureka process. The vacuum residues were derived from three Kuwaiti crude oils, both conventional and heavy. Experimental data was obtained at three Cracking temperatures (400, 415, and 430 °C) and three reaction times (30, 50, and 60 min). The proposed Thermal Cracking kinetic model is based on the discrete lumping approach. The reaction scheme consisted of five lumps: the four cracked products and residual unconverted oil. The cracked products represent the product slates obtained from the commercial Eureka process, namely, the off-gases ( 538 °C). The analysis of the results revealed that the Thermal Cracking of vacuum residue follows first order kinetics. The proposed model predicted the kinetic parameters for the Thermal Cracking of different residual feedstock and provided a good fit to the experimental data.
Thomas Kaminski - One of the best experts on this subject based on the ideXlab platform.
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kinetic modelling of Thermal Cracking of arabian atmospheric and vacuum residue
Fuel Processing Technology, 2019Co-Authors: Thomas Kaminski, Mae M HuseiAbstract:Abstract Kinetic modelling of Arabian atmospheric residue (AR) and vacuum residue (VR) undergoing Thermal Cracking at 400 °C to 420 °C in an autoclave is detailed in this study. A five-lump model based on the gas, coke, asphaltene, maltene and distillate fractions is developed. Three reaction schemes encompassing 6, 10 or 13 reaction pathways, with the corresponding fitted parameters, are compared. Additionally, coke induction is captured using a step function. Fitting AR experimental results revealed that the root mean squared deviations (RMSE) for the 6-reaction scheme almost equalled the 10- and the 13-reaction schemes and the fit showed the same accuracy. The 6-reaction scheme model was then fitted to slurry catalytic Thermal Cracking of AR mediated by drill cuttings. A comparison between the kinetic parameters confirmed the catalytic role of the drill cuttings, despite their non-porous morphology, and lower activation energy for distillate formation was observed. Lastly, the 6-reaction, AR-fitted model was employed to predict experimental data from non-catalytic and catalytic Thermal Cracking of VR. The model could predict the non-catalytic runs to a better extent. Failure to predict the catalytic Cracking of VR is attributed to rapid deactivation of the drill cuttings arising from the difference in the nature and concentration of asphaltenes and the hydrogen donors in the VR relative to the AR feedstock.
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Thermal Cracking of atmospheric residue versus vacuum residue
Fuel Processing Technology, 2018Co-Authors: Thomas Kaminski, Maen M. HuseinAbstract:Abstract Current practice subjects atmospheric residue (AR) to vacuum distillation, while feeding the vacuum residue (VR) for upgrading. This study explores the direct upgrading of AR and gauges the potential for eliminating the vacuum distillation unit, while recycling the upgraded oil to the atmospheric distillation column. Thermal Cracking of Arabian AR and VR was carried out in an autoclave for 1 h at 400 °C. AR provided much higher liquid yield and quality with limited coke yield (
Xiaoxiong Zhang - One of the best experts on this subject based on the ideXlab platform.
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experiment and modeling on Thermal Cracking of n dodecane at supercritical pressure
Energy & Fuels, 2018Co-Authors: Dingrui Zhang, Xiaoxiong ZhangAbstract:A comprehensive understanding of the Thermal Cracking behavior of hydrocarbon fuels is important for Thermal protection applications and investigations into the combustion of Thermally cracked fuels. In the present study, n-dodecane is selected as a surrogate for aviation kerosene and it is subjected to a series of Thermal Cracking experiments at supercritical pressure. According to variations in chemical heat sink, fuel-conversion rate, and gas-production rate, the Thermal Cracking of n-dodecane is divided into three regions: primary, secondary, and severe. In the primary Cracking region, the fuel-conversion rate is lower than 13%, and the liquid products contain only chain alkanes and alkenes. Owing to the mass fraction of main products being proportional to the fuel-conversion rate, a one-step global reaction kinetics is constructed. The secondary Cracking region is characterized by rapidly increasing chemical heat sink, fuel-conversion rates, and gas-production rates with increasing fuel temperature, ...
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interaction between Thermal Cracking and steam reforming reactions of aviation kerosene
Fuel Processing Technology, 2017Co-Authors: Dingrui Zhang, Xiaoxiong ZhangAbstract:Abstract Heat transfer and reaction behavior of aviation kerosene were investigated numerically and experimentally at a supercritical pressure. A global Thermal Cracking and catalytic reforming reaction model were modified and developed based on the experimental data. A set of surrogate components for aviation kerosene was built and its thermodynamic properties were predicted. Interactions among heat transfer, Cracking and catalytic steam reforming reactions were simulated in a micro-channel reactor. Comparison between calculation and experiment showed that the numerical model can predict the wall and outlet fuel temperatures with an error not exceeding 5%. The conversion rate of kerosene and water were also in good agreement with experimental data. Heat transfer deterioration phenomenon can be observed when fuel contains water. Fuel with catalytic steam reforming reactions had the advantage of weakening the heat transfer deterioration and obvious promotion in heat sink. Heat transfer process can be divided into four sub-regions: entrance, gasification, transition and interactive reaction regions. The two kinds of reactions occurring in the reaction region significantly improve the heat sink of hydrocarbon fuel. Interactions between Cracking and reforming reactions illustrated that the reaction region were considerably moved ahead due to the existing of steam reforming reactions, resulting in lower fuel temperature which led to a lower rate of Thermal Cracking and conversion. Thermal Cracking reaction was inhibited by catalytic steam reforming reactions.
