Dalia S. Makki, Hasan Sh. Majdi, Amer A. Abdulrahman, Abbas J. Sultan, Bashar J. Kadhim, Zahraa W. Hasan
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引用次数: 0
Abstract
To improve the design and scale-up processes of bubble column reactors (BCRs), it is necessary to characterize the hydrodynamics by means of flow regime behavior. This study examines the impact of industrial heat exchangers and superficial gas velocities on flow regimes, pressure drop, and gas holdup in BC and SBC. A simulated Fischer–Tropsch bubble column is constructed. The experimental study utilized a Perspex column with a diameter of 0.14 m. Moreover, 18 copper tubes with a 0.16 m diameter are fitted into the bubble column. The selection of tubes in SBC was carried out in accordance with TEMA recommendations to ensure optimal heat dissipation. These tubes were made to resemble the industrial Fischer–Tropsch reactor by covering 25% of the bubble column’s cross-sectional area. In order to enhance the measurement and comprehension of the hydrodynamics within the reactor, this study employs a method measured the total gas hold-up and detected pressure fluctuations using three differential pressure transducers (Keller type PA 21Y/4). The column was equipped with a perforated plate air distributor, and glass beads were used as the solid phase. The gas distributor is constructed of porous polyethylene with pore sizes of 0.5 mm and plate thicknesses of 3 mm. To comprehend and assess the impact of tube configuration on the pressure drop; gas holdup; and regime transition velocities, the experimental data were recorded across a broad range of superficial gas velocities (i.e., 0.036–0.27 m/s). The findings suggest that higher superficial gas velocities result in amplified pressure fluctuations, with a recorded increase of 0.108 to 0.15 bar in pressure drop at a gas velocity of 0.27 m/s in the air-water system. Equipping the bubble/slurry bubble column with an industrial heat exchanger to the bubble/slurry bubble column resulted in a modest increase in pressure drop of around 0.042 bar, which disrupted the uniform flow and delayed regime transitions. Furthermore, the inclusion of solids leads to a 10% decrease in gas holdup, while the heat exchanger only slightly improves it by 5%. Drift flux analysis is a helpful tool for determining transition points. In the case of U-shaped heat exchanger tubes, the transition velocities can be altered by 1.7 m/s in BC. The results of this investigation will offer an exhaustive understanding of fluid dynamics as well as guidance in the design of reactors for extremely exothermic processes.
期刊介绍:
Petroleum Chemistry (Neftekhimiya), founded in 1961, offers original papers on and reviews of theoretical and experimental studies concerned with current problems of petroleum chemistry and processing such as chemical composition of crude oils and natural gas liquids; petroleum refining (cracking, hydrocracking, and catalytic reforming); catalysts for petrochemical processes (hydrogenation, isomerization, oxidation, hydroformylation, etc.); activation and catalytic transformation of hydrocarbons and other components of petroleum, natural gas, and other complex organic mixtures; new petrochemicals including lubricants and additives; environmental problems; and information on scientific meetings relevant to these areas.
Petroleum Chemistry publishes articles on these topics from members of the scientific community of the former Soviet Union.