The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
William L Roberts - One of the best experts on this subject based on the ideXlab platform.
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Cenosphere Formation during Single-Droplet Combustion of Heavy Fuel Oil
Energy & Fuels, 2019Co-Authors: Long Jiang, Paolo Guida, Ayman El-baz, Saeed M. Al-noman, Ibrahim A. Alghamdi, Saumitra Saxena, William L RobertsAbstract:The current study aims to investigate cenosphere formation during single-droplet combustion of heavy Fuel Oil (HFO). A droplet generator was developed to produce freely falling monodisperse droplets uniformly. With the aid of high-speed imaging, droplet diameter was verified to be well controlled within the range of 390–698 μm, and droplets spacing distance was sufficient to avoid droplet–droplet interactions. Impacts of operation conditions (initial HFO droplet size, temperature, and air co-flow rate) and asphaltene content on cenosphere formation in a drop tube furnace were then investigated. Three types of cenosphere morphology were observed by field emission scanning electron microscopy (SEM), namely, larger hollow globules, medium porous cenospheres, and smaller cenospheres with a perfectly spherical and smooth structure. The SEM results show that the mean diameter of collected cenospheres increased as initial droplet size and asphaltene content increased, while it decreased as temperature and air co...
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Cenosphere Formation during Single-Droplet Combustion of Heavy Fuel Oil
2019Co-Authors: Long Jiang, Paolo Guida, Saeed M. Al-noman, Ibrahim A. Alghamdi, Saumitra Saxena, Ayman M. Elbaz, William L RobertsAbstract:The current study aims to investigate cenosphere formation during single-droplet combustion of heavy Fuel Oil (HFO). A droplet generator was developed to produce freely falling monodisperse droplets uniformly. With the aid of high-speed imaging, droplet diameter was verified to be well controlled within the range of 390–698 μm, and droplets spacing distance was sufficient to avoid droplet–droplet interactions. Impacts of operation conditions (initial HFO droplet size, temperature, and air co-flow rate) and asphaltene content on cenosphere formation in a drop tube furnace were then investigated. Three types of cenosphere morphology were observed by field emission scanning electron microscopy (SEM), namely, larger hollow globules, medium porous cenospheres, and smaller cenospheres with a perfectly spherical and smooth structure. The SEM results show that the mean diameter of collected cenospheres increased as initial droplet size and asphaltene content increased, while it decreased as temperature and air co-flow rate increased. Energy-dispersive X-ray spectroscopy results show that these parameters also significantly influenced the evolution of cenosphere surface elemental composition. All parameters show linear effects on the surface content of C, O, and S, excluding air co-flow rate. The increase of air co-flow temperature enhanced droplet combustion; conversely, larger initial droplet size and asphaltene content inhibited droplet combustion. The nonlinear effect of air co-flow rate indicates that it has an optimum rate for falling droplet combustion, as 90 slpm based on the current experimental setup. Eventually, our study proposed the pathway of cenosphere formation during the HFO droplet combustion
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Influence of Asphaltene Concentration on the Combustion of a Heavy Fuel Oil Droplet
Energy & Fuels, 2018Co-Authors: Abdulrahman A. Khateeb, Paolo Guida, William L RobertsAbstract:Heavy Fuel Oils consist of a blend of middle distillates, mainly diesel Fuel, and heavy Oil residuals. Varying the fraction of the mixture changes the weight percentage of the asphaltene in the heavy Fuel Oil (HFO) sample. Asphaltene is a very high molecular weight complex component in the Fuel that increases the Fuel viscosity, surface tension, and chemical reaction rate. Here, we investigate the influence of high asphaltene concentration on the combustion of a single HFO droplet. In this experimental work, we used the thermogravimetric analysis (TGA) and the suspended droplet techniques. We tested HFO samples containing asphaltene at 8, 16, 24 wt % (HFO8, HFO16, and HFO24). The TGA result shows a residual amount of approximately 2.4 wt % of HFO24 compared to no residuals for HFO8 at the end of the process. The suspended droplet technique results reveal the following seven consecutive burning stages for the entire burning process of the liquid and solid phases: (1) preheating, (2) flame startup, (3) inne...
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tg dtg ft icr mass spectrometry and nmr spectroscopy study of heavy Fuel Oil
Energy & Fuels, 2015Co-Authors: Ayman Elbaz, Abdul Gani, Nadim Hourani, Abdulhamid Emwas, Mani S Sarathy, William L RobertsAbstract:There is an increasing interest in the comprehensive study of heavy Fuel Oil (HFO) due to its growing use in furnaces, bOilers, marines, and recently in gas turbines. In this work, the thermal combustion characteristics and chemical composition of HFO were investigated using a range of techniques. Thermogravimetric analysis (TGA) was conducted to study the nonisothermal HFO combustion behavior. Chemical characterization of HFO was accomplished using various standard methods in addition to direct infusion atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (APCI-FTICR MS), high resolution 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional heteronuclear multiple bond correlation (HMBC) spectroscopy. By analyzing thermogravimetry and differential thermogravimetry (TG/DTG) results, three different reaction regions were identified in the combustion of HFO with air, specifically, low temperature oxidation region (LTO), Fuel deposition (FD), and hig...
Jean Koulidiati - One of the best experts on this subject based on the ideXlab platform.
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study of droplet vaporization of various vegetable Oils and blends of domestic Fuel Oil cottonseed Oil under different ambient temperature conditions
Biomass & Bioenergy, 2012Co-Authors: T. Daho, O Sanogo, G. Vaitilingom, Salifou K. Ouiminga, B.g. Segda, Pascal Higelin, Jérémy Valette, Jean KoulidiatiAbstract:In this work, the evaporation characteristics of different pure vegetable Oils (cottonseed Oil, jatropha Oil, and rapeseed Oil), domestic Fuel Oil (DFO) and blends of domestic Fuel Oil and cottonseed Oil have been studied using the fibre-suspended droplet evaporation technique. The constants of evaporation of pure products were determined as well as the influence of the proportion of DFO fraction on the mechanisms of vaporization process of cottonseed Oil in the temperature range of 578 K-917 K under atmospheric pressure. The results show that the DFO evaporates completely in the range of temperatures considered in contrast to vegetable Oils that vaporize completely only for temperatures higher than or equal to 773 K. Above 873 K, the behaviour of vegetable Oils becomes similar to a single component product and the d(2) law is respected. At a given temperatures range, constants of evaporation of the three vegetable Oils are of the same order of magnitude. The results also show that blends of cottonseed Oil and DFO vaporize following a sequential distillation mechanism: DFO is evaporating first, followed by a transient phase, and then cottonseed Oil vaporizes following the same trends than observed for pure vegetable Oils. For low percentages of cottonseed Oil (<= 40%) in the mixture, formation of bubbles can be observed at the end of the process at 684 K. When the concentration of vegetable Oil in the droplet increases, the mechanism of pure diffusion becomes predominant. (C) 2012 Elsevier Ltd. All rights reserved.
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study of droplet vaporization of various vegetable Oils and blends of domestic Fuel Oil cottonseed Oil under different ambient temperature conditions
Biomass & Bioenergy, 2012Co-Authors: T. Daho, O Sanogo, G. Vaitilingom, Salifou K. Ouiminga, B.g. Segda, Pascal Higelin, Jérémy Valette, Jean KoulidiatiAbstract:In this work, the evaporation characteristics of different pure vegetable Oils (cottonseed Oil, jatropha Oil, and rapeseed Oil), domestic Fuel Oil (DFO) and blends of domestic Fuel Oil and cottonseed Oil have been studied using the fibre-suspended droplet evaporation technique. The constants of evaporation of pure products were determined as well as the influence of the proportion of DFO fraction on the mechanisms of vaporization process of cottonseed Oil in the temperature range of 578 K-917 K under atmospheric pressure. The results show that the DFO evaporates completely in the range of temperatures considered in contrast to vegetable Oils that vaporize completely only for temperatures higher than or equal to 773 K. Above 873 K, the behaviour of vegetable Oils becomes similar to a single component product and the d(2) law is respected. At a given temperatures range, constants of evaporation of the three vegetable Oils are of the same order of magnitude. The results also show that blends of cottonseed Oil and DFO vaporize following a sequential distillation mechanism: DFO is evaporating first, followed by a transient phase, and then cottonseed Oil vaporizes following the same trends than observed for pure vegetable Oils. For low percentages of cottonseed Oil (<= 40%) in the mixture, formation of bubbles can be observed at the end of the process at 684 K. When the concentration of vegetable Oil in the droplet increases, the mechanism of pure diffusion becomes predominant. (C) 2012 Elsevier Ltd. All rights reserved.
Antonio Diegomarin - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of the effect of water content on combustion of heavy Fuel Oil water emulsion droplets
Combustion and Flame, 2001Co-Authors: Rene Ocampobarrera, Rafael Villasenor, Antonio DiegomarinAbstract:Experiments of isolated high asphaltene droplets of heavy Fuel Oil/water emulsion were performed to investigate the non-steady behavior of the burning droplets. High-resolution video methods allowed monitoring of the various combustion stages. A highly radiant (1000 °C/s) oxidizing environment was necessary to enhance the volatility differential of the high asphaltene Fuel, thus reducing uncertainties because of the presence of the fiber. Data on size and temperature histories were obtained and coke residues were analyzed by a Scanning Electron Microscope. A lower and upper bound for ignition time delay was established. The error defined as the time lag between these two limits never exceeded 10 ms, which is the maximum time for soot to form in the flame after actual ignition. The ignition time delay of emulsions was longer than for an ordinary heavy Fuel Oil (HFO) droplets of the same size. The peak temperature of emulsions occurred much earlier in time. The steeper temperature rise seen in the emulsions for portions of their combustion history is evidence of both soot reduction and the extent of burnout of the cenospheres, which is an important aspect in the reduction of pollutant emissions. The occurrence of swelling, disruptive bOiling, splashing and the formation of coke were clearly identified by three characteristic combustion times. The emulsion droplets showed swellings of considerable magnitude relative to that of HFO. Coking of the solid phase took place by a dramatic eruption during the last moments of the droplet lifetime when the molecular structure of the cenosphere appeared to be molded. Coke particles formed from emulsions were more void with thinner and fragile shells suggesting that an amorphous-like molecular structure could have developed as opposed to the more compact shell structure observed for HFO residues, which were harder and more reticent to burning. Excess burnout time or the ratio of burnout time of the emulsions was dependent on the water concentration, indicating that less oxidation time was required for coke particles from emulsions than from heavy Fuel Oil.
T. Daho - One of the best experts on this subject based on the ideXlab platform.
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study of droplet vaporization of various vegetable Oils and blends of domestic Fuel Oil cottonseed Oil under different ambient temperature conditions
Biomass & Bioenergy, 2012Co-Authors: T. Daho, O Sanogo, G. Vaitilingom, Salifou K. Ouiminga, B.g. Segda, Pascal Higelin, Jérémy Valette, Jean KoulidiatiAbstract:In this work, the evaporation characteristics of different pure vegetable Oils (cottonseed Oil, jatropha Oil, and rapeseed Oil), domestic Fuel Oil (DFO) and blends of domestic Fuel Oil and cottonseed Oil have been studied using the fibre-suspended droplet evaporation technique. The constants of evaporation of pure products were determined as well as the influence of the proportion of DFO fraction on the mechanisms of vaporization process of cottonseed Oil in the temperature range of 578 K-917 K under atmospheric pressure. The results show that the DFO evaporates completely in the range of temperatures considered in contrast to vegetable Oils that vaporize completely only for temperatures higher than or equal to 773 K. Above 873 K, the behaviour of vegetable Oils becomes similar to a single component product and the d(2) law is respected. At a given temperatures range, constants of evaporation of the three vegetable Oils are of the same order of magnitude. The results also show that blends of cottonseed Oil and DFO vaporize following a sequential distillation mechanism: DFO is evaporating first, followed by a transient phase, and then cottonseed Oil vaporizes following the same trends than observed for pure vegetable Oils. For low percentages of cottonseed Oil (<= 40%) in the mixture, formation of bubbles can be observed at the end of the process at 684 K. When the concentration of vegetable Oil in the droplet increases, the mechanism of pure diffusion becomes predominant. (C) 2012 Elsevier Ltd. All rights reserved.
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study of droplet vaporization of various vegetable Oils and blends of domestic Fuel Oil cottonseed Oil under different ambient temperature conditions
Biomass & Bioenergy, 2012Co-Authors: T. Daho, O Sanogo, G. Vaitilingom, Salifou K. Ouiminga, B.g. Segda, Pascal Higelin, Jérémy Valette, Jean KoulidiatiAbstract:In this work, the evaporation characteristics of different pure vegetable Oils (cottonseed Oil, jatropha Oil, and rapeseed Oil), domestic Fuel Oil (DFO) and blends of domestic Fuel Oil and cottonseed Oil have been studied using the fibre-suspended droplet evaporation technique. The constants of evaporation of pure products were determined as well as the influence of the proportion of DFO fraction on the mechanisms of vaporization process of cottonseed Oil in the temperature range of 578 K-917 K under atmospheric pressure. The results show that the DFO evaporates completely in the range of temperatures considered in contrast to vegetable Oils that vaporize completely only for temperatures higher than or equal to 773 K. Above 873 K, the behaviour of vegetable Oils becomes similar to a single component product and the d(2) law is respected. At a given temperatures range, constants of evaporation of the three vegetable Oils are of the same order of magnitude. The results also show that blends of cottonseed Oil and DFO vaporize following a sequential distillation mechanism: DFO is evaporating first, followed by a transient phase, and then cottonseed Oil vaporizes following the same trends than observed for pure vegetable Oils. For low percentages of cottonseed Oil (<= 40%) in the mixture, formation of bubbles can be observed at the end of the process at 684 K. When the concentration of vegetable Oil in the droplet increases, the mechanism of pure diffusion becomes predominant. (C) 2012 Elsevier Ltd. All rights reserved.
Yusaku Sakata - One of the best experts on this subject based on the ideXlab platform.
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recycling of waste lubricant Oil into chemical feedstock or Fuel Oil over supported iron oxide catalysts
Fuel, 2004Co-Authors: Thallada Bhaskar, Akinori Muto, Azhar Uddin, Yusaku Sakata, Yoji Omura, Kenji Kimura, Yasuhisa KawakamiAbstract:The recycling of waste lubricant Oil from automobile industry was found to be best alternative to incineration. Silica (SiO2), alumina (Al2O3), silica–alumina (SiO2–Al2O3) supported iron oxide (10 wt% Fe) catalysts were prepared by wet impregnation method and used for the desulphurisation of waste lubricant Oil into Fuel Oil. The extent of sulphur removal increases in the sequence of Fe/SiO2–Al2O3
thermal conductivity detector analysis confirms the presence of H2S in gaseous products. In addition, Fe/SiO2 catalyst facilitated the formation of lower hydrocarbons by cracking higher hydrocarbons (≈C40) present in waste lubricant Oil. -
catalytic dehydrochlorination of chloro organic compounds from pvc containing waste plastics derived Fuel Oil over fecl2 sio2 catalyst
Green Chemistry, 2001Co-Authors: N. Lingaiah, Akinori Muto, Md. Azhar Uddin, K Morikawa, Katsuhide Murata, Yusaku SakataAbstract:A highly selective and stable FeCl2/SiO2 catalyst system was studied for the dehydrochlorination of various chloro-organic compounds from the Fuel Oil derived from polyvinyl chloride (PVC) containing waste plastics.
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thermal and catalytic degradation of structurally different types of polyethylene into Fuel Oil
Polymer Degradation and Stability, 1997Co-Authors: Azhar Uddin, Kazuo Koizumi, Katsuhide Murata, Yusaku SakataAbstract:The degradation of four different types of polyethylene (PE) namely high density PE (HDPE), low density PE (LDPE), linear low density PE (LLDPE), and cross-linked PE (XLPE) was carried out at 430 °C by batch operation using silica-alumina as a solid acid catalyst and thermally without any catalyst. For thermal degradation, both HDPE and XLPE produced a significant amount of wax-like compounds and the yields of liquid products (58–63 wt%) were lower than that of LDPE and LLDPE (76–77 wt%). LDPE and LLDPE produced a very small amount of wax-like compounds. Thus the structure of the degrading polymers influenced the product yields. The liquid products from thermal degradation were broadly distributed in the carbon fraction of n-C5 to n-C25 (bOiling point range, 36–405 °C). With silica-alumina, all of the polyethylenes were converted to liquid products with high yields (77–83 wt%) and without any wax production. The liquid products were distributed in the range of n-C5 to n-C20 (mostly C5–C12). A solid acid catalyst indiscriminately degraded the various types of polyethylene into light Fuel Oil with an improved rate.
