The Experts below are selected from a list of 3510 Experts worldwide ranked by ideXlab platform
Edward Chan - One of the best experts on this subject based on the ideXlab platform.
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effect of injection nozzle operating parameters on the interaction between a gas liquid jet and a gas solid fluidized bed
2008Co-Authors: Federica Portoghese, L Ferrante, Franco Berruti, Cedric Briens, Edward ChanAbstract:Abstract The objective of the present study was to provide insight into the effect of operating conditions on the performance of gas-assisted nozzles injecting liquid into gas–solid fluidized beds. Acquisition of such knowledge is relevant to many industrial applications where liquid injections into fluidized beds of solid particles are performed via spray nozzles. In the fluid Coking Process, for example, product yields and reactor operability strongly benefit from a rapid and uniform distribution of the liquid feed on fluidized solid particles, which, in turn, is greatly affected by the performance of the liquid-injection system used. A novel experimental technique was employed to investigate the effect of varying the air-to-liquid ratio (ALR), the liquid mass flow rate, and the nozzle size on the contact efficiency of injected liquid on fluidized bed particles. Increasing the ALR or the liquid flow rate increased the nozzle spraying efficiency. On the contrary, increasing the nozzle size while keeping the gas and the liquid flow rates constant, and hence decreasing the pressure at the nozzle tip, lowered the liquid–solid contact efficiency. The effect of increasing the ALR on the liquid–solid contact resulting from nozzle-injections into the fluid bed, was correlated to both the nozzle atomization performance, as determined by open-air tests using a laser-photocell equipment, and the solids entrainment into the gas–liquid jet, as predicted by a model.
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solids entrainment into gas liquid and gas liquid spray jets in fluidized beds
2008Co-Authors: Cedric Briens, Franco Berruti, Vittorio Felli, Edward ChanAbstract:Abstract The injection of liquid into a fluidized bed is a crucial step in many Processes such as fluid Coking, fluid catalytic cracking, or gas-phase polymerization, whose performance greatly depends on good and rapid contact between the injected liquid and the fluidized particles. The liquid spray, created by two-phase (gas–liquid) nozzles, forms a jet, i.e. a gas-rich cavity within the fluidized bed. Past studies have shown that good liquid–solid contact requires a large entrainment rate of particles into the jet, followed by intensive mixing of liquid droplets and entrained particles within the jet. The objective of this study is the experimental measurement of solids entrainment into spray jets. The specific application of interest is the enhancement of solids entrainment under conditions relevant to the fluid Coking Process. A novel and accurate experimental technique has been developed to measure the solids entrainment from a fluidized bed into two-phase gas–liquid jets, gas jets and liquid jets. The effects of operating conditions of the nozzle (sonic versus subsonic) and of the fluidized bed on the solids entrainment have been investigated. The differences between the mechanisms of solids entrainment for two-phase gas–liquid, gas and liquid jets have been analyzed. This experimental tool has been applied to the design and testing of a mixing chamber consisting of a cylindrical tube placed at a certain distance downstream of the nozzle tip, resulting in a confined, turbulent jet with enhanced liquid–solid mixing properties.
Zhirong Yang - One of the best experts on this subject based on the ideXlab platform.
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distribution characteristics of Coking products and mechanism of tar lightening in preparation of high strength gasification coke with low rank coal blending
2019Co-Authors: Zhirong Yang, Jiejie Huang, Xuezhi Duan, Jing Zhang, Xinggui ZhouAbstract:During the preparation of high-strength gasification-coke with low-rank coal blending, evolution of pyrolysis tar and gas is still unclear for situations where large amounts of low-rank coal are blended. Herein, the effect of low-rank coal blending on the distribution of Coking products was thoroughly investigated and the mechanism of tar lightening was studied by simulating the Coking Process with 1 kg laboratory-scale coke oven. The results showed that more liquids but less gases were formed compared to the theoretically calculated values due to a stronger cohesive interaction in the coal blending system. Moreover, the gas yield and volatile matters in dry ash-free basis (Vdaf) showed an opposite linear correlation for single coal and blended coal, probably due to this strong cohesive interaction. The facileness of long-chain aliphatic hydrocarbons to crack into low-molecular-weight hydrocarbons is attributed to their weaker interactions with more low-rank coal blends. The low-rank coal blending signifi...
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insight into the effects of additive water on caking and Coking behaviors of coal blends with low rank coal
2019Co-Authors: Zhirong Yang, Jiejie Huang, Shuangshuang Song, Zhiqing Wang, Yitian FangAbstract:Abstract Additive water is usually needed to preserve 9–11% moisture content of blended coal in the stamp-charging Coking Process, which in fact is unfavorable for Coking property. An insight into the improvement of Coking property of coal blends with much low-rank coal (long flame coal SFC, lignite HLH) by regulating additive water was proposed in terms of its effects on the metaplast fluidity and the particle agglomeration behavior. The results indicate that the cohesiveness of gas coals (GC) can be properly enhanced by adding water. The restrictions on the condensation of aromatic structures and the break-up of –CH2– structure and the development of the polyhydroxy groups in aromatic structures are favorable to increase the fluidity of metaplast after adding water, as demonstrated by the optical texture and FTIR analysis of the semicoke (450 °C). The great difference in the hydrophilic properties for various rank coals leads to the particle agglomeration of gas coal and fat coal (GC and FC), which makes them difficult to mix uniformly with SFC after adding water, thus reduces the Coking property. A reasonable approach of adding water suggests that H2O and SFC should be well mixed prior to blending with caking coals, which can lead to a uniform particle distribution and a better Coking property. This approach promotes the direct and efficient utilization of low-rank coal (especially lignite) by the blending Coking with no or less drying and dewatering Processes.
Jocelyn E Zuliani - One of the best experts on this subject based on the ideXlab platform.
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characterization of vanadium in oil sands fluid petroleum coke using electron microscopy
2016Co-Authors: Jocelyn E Zuliani, Tomohiro Miyata, Teruyasu Mizoguchi, Jing Feng, Donald W Kirk, Charles Q JiaAbstract:Abstract Naturally occurring vanadium is found in many heavy oils and bitumen, which are upgraded to synthetic crude oil via the Coking Process. During Coking the vanadium concentrates in the solid heavy oil product, petroleum coke. However, potential releases of this toxic vanadium, either due to long term natural leaching from stockpiles or during combustion, presents environmental and health concerns. In this study, the vanadium present in petroleum coke was characterized using high resolution transmission electron microscope imaging with energy-dispersive X-ray spectroscopy. Vanadium was observed in nanocrystalline mineral clusters, and is consistently associated with silicon, oxygen, sulfur, and iron. A distinct lattice structure is observed in these nanocrystals. This result is different from previous theories, which predicted that the Coking Process did not decompose the vanadyl porphyrins present in bitumen. By identifying the vanadium nanocrystals in petroleum coke, the long term fate of vanadium in petroleum coke stockpiles in reclaimed land may be predicted.
Merrick R Mahoney - One of the best experts on this subject based on the ideXlab platform.
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a review of the state of the art research on carbon structure evolution during the Coking Process from plastic layer chemistry to 3d carbon structure establishment
2020Co-Authors: Yixin Chen, Soonho Lee, Arash Tahmasebi, Jin Bai, Merrick R MahoneyAbstract:Abstract This paper provides a review of the state-of-the-art research in the open literature on the carbon structure evolution in the semi-coke region following the last stage of the plastic layer transformation. Coking coals exhibit thermoplastic fluid-like behavior due to the change of chemical structures in plastic layers when heated in the coke ovens. Once the temperature of the coal charge exceeds the thermoplastic range, condensation, cross-linking, and repolymerization reactions take place. This results in the formation of a more ordered structure, referred to as semi-coke, with the final release of light gases. A further temperature increase leads to the release of hydrogen from the aromatic hydrocarbon structures with the formation of C–C bonds and, consequently, the carbon structure, which corresponds to the gradual transformation from the semi-coke to high-temperature coke. A variety of advanced analytical techniques have been employed, including infrared spectroscopy (IR), solid-state carbon-13 nuclear magnetic resonance (13C NMR) and X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. The carbon structure in coke generally is generally in the form of non-graphitic turbostratic structure, which exhibits isotropic property. There is a lack of information in terms of the 3D carbon structure model of coke/semi-coke and how these structures evolve from hydrocarbon sheets to more stable structures above 500 °C in the coke oven. This review also concludes future research scopes and the limitations of current knowledge.
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study of chemical structure transition in the plastic layers sampled from a pilot scale coke oven using a thermogravimetric analyzer coupled with fourier transform infrared spectrometer
2019Co-Authors: Soonho Lee, Merrick R Mahoney, Priscilla Tremain, Behdad Moghtaderi, Arash Tahmasebi, Rohan Stanger, T F Wall, John LucasAbstract:Abstract The aim of this study was to characterize the pyrolysis behavior of the plastic layer formed during the Coking Process in a 4 kg laboratory-scale coke oven facility. The 4 kg coke oven rig was used to produce semi-coke samples that included the plastic layer. The semi-coke samples were analyzed by using the Synchrotron Micro-CT to characterize their physical structures and identify the plastic layer features. Sectioned plastic layer samples corresponding to softening, maximum fluidity, and resolidification of coal were obtained for five Coking coals of varying thermoplastic properties. Pyrolysis behavior and structural changes of the plastic layer samples were analyzed by a thermogravimetric analyzer coupled with a Fourier transform infrared spectroscopy (TG-FTIR) and an attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The TG-FTIR analysis allowed the characterization of the changes in pyrolysis behavior including volatile matter yields, the changes in aliphatic and aromatic C–H structures in the sectioned plastic layer samples. These structure changes agreed well with the ATR-FTIR analysis which also showed chemical structure changes across the plastic layer. The results suggest that the aliphatic C–H bonds of the five coals underwent the greatest reduction with the progression of the Coking Process in the coal charge. It was observed that the aliphatic C–H across the thermoplastic layer region varied with the thermoplastic properties of the parent coal. This implies that the aliphatic structures in coal may have played a significant role in the development of thermoplastic properties during the formation of the plastic layer.
Charles Q Jia - One of the best experts on this subject based on the ideXlab platform.
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characterization of vanadium in oil sands fluid petroleum coke using electron microscopy
2016Co-Authors: Jocelyn E Zuliani, Tomohiro Miyata, Teruyasu Mizoguchi, Jing Feng, Donald W Kirk, Charles Q JiaAbstract:Abstract Naturally occurring vanadium is found in many heavy oils and bitumen, which are upgraded to synthetic crude oil via the Coking Process. During Coking the vanadium concentrates in the solid heavy oil product, petroleum coke. However, potential releases of this toxic vanadium, either due to long term natural leaching from stockpiles or during combustion, presents environmental and health concerns. In this study, the vanadium present in petroleum coke was characterized using high resolution transmission electron microscope imaging with energy-dispersive X-ray spectroscopy. Vanadium was observed in nanocrystalline mineral clusters, and is consistently associated with silicon, oxygen, sulfur, and iron. A distinct lattice structure is observed in these nanocrystals. This result is different from previous theories, which predicted that the Coking Process did not decompose the vanadyl porphyrins present in bitumen. By identifying the vanadium nanocrystals in petroleum coke, the long term fate of vanadium in petroleum coke stockpiles in reclaimed land may be predicted.