Interfacial area for concurrent gas–liquid upflow through packed bed

Rao, A. V. Raghavendra; Kumar, Ramesh; Sankarshana, T.; Khan, Ahamed

doi:10.1002/cjce.20354

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…Figure shows variation of the interfacial area with the size of the packing. It is observed that the bed with smaller packing has a higher interfacial area, which is in agreement with work by Mashelkar and Sharma and Rao et al In general, the bed packed with smaller packing has a higher pressure drop and therefore a higher shearing force on the bubbles, which consequently reduces the bubble size and leads to a larger gas–liquid interfacial area.…”

Section: Resultssupporting

confidence: 90%

“…In the bubble-flow regime, the interfacial area is substantially related to the number and size of the bubbles, which are probably little affected by the liquid flow rate. However, in the pulsing-flow regime, it is mainly due to the formation of liquid droplets . Therefore, we can see from Figure that the interfacial area is substantially retained with the liquid flow rate at low gas flow rates, but it has a slight increase with the liquid flow rate when it turns into the pulsing-flow regime.…”

Section: Resultsmentioning

confidence: 86%

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Packing Size Effect on the Mean Bubble Diameter in a Fixed Bed under Gas–Liquid Concurrent Upflow

Chen

Jian-hui

Ling

et al. 2017

Ind. Eng. Chem. Res.

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The influence of the packing size on the mean bubble diameter in a flooded bed reactor packed with glass spheres of three different diameters (1.9, 4.0, and 9.3 mm) was investigated. The gas saturation and interfacial area were respectively measured by electrical capacitance tomography and chemical absorption of oxygen. It is observed that the presence of packing has greatly reduced the bubble diameter and increased the gas saturation compared with a bubble column. To explore the underlying relationship between the bubble diameter and packing size, the packing size featured by the pore diameter was utilized as a reference. It shows that the bubble diameter is 2–3 times the pore for the 1.9 and 4.0 mm packings, while they are approached for the packing of 9.3 mm. An empirical correlation was proposed for the mean bubble diameter prediction with a discrepancy of less than 25% from the measurements.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 86%

Packing Size Effect on the Mean Bubble Diameter in a Fixed Bed under Gas–Liquid Concurrent Upflow

Chen

Jian-hui

Ling

et al. 2017

Ind. Eng. Chem. Res.

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Hydrodynamics and mass transfer enhancement of gas–liquid flow in micropacked bed reactors: Effect of contact angle

et al. 2022

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Pressure drop, residence time distribution, dispersive behavior, liquid holdup, and mass transfer performance of gas–liquid flow in micropacked bed reactors (μPBRs) with different contact angles (CA) of particles are studied. The value of pressure drop for three types of beads can be obtained: copper beads (CA = 88.1°) > stainless steel beads (CA = 70.2°) > glass beads (CA = 47.1°). The liquid axial dispersion coefficient is 1.58 × 10−6 to 1.07 × 10−5 m2/s for glass beads and copper beads, which is smaller than those of trickle bed reactors. The liquid holdup of 400 μm copper beads is larger than that of 400 μm glass beads. The ratio of effective interfacial area enhancement is evaluated up to 55% for big contact angle beads compared with the hydrophilic glass beads. In addition, correlations of pressure drop, liquid holdup, and effective interfacial area in μPBRs with different wettability beads are developed and predicted values are in agreement with the experimental data.

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Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

Collins

Sederman

Gladden

et al. 2017

Chemical Engineering Science

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Magnetic resonance (MR) imaging techniques have been used to study gas phase dynamics during co-current up-flow in a column of inner diameter 43 mm, packed with spherical nonporous elements of diameters of 1.8, 3 and 5 mm. MR measurements of gas holdup , bubblesize distribution, and bubble-rise velocities were made as a function of flow rate and packing size. Gas and liquid flow rates were studied in the range of 20-250 cm 3 s-1 and 0-200 cm 3 min-1 , respectively. The gas holdup within the beds was found to increase with gas flow rate, while decreasing with increasing packing size and to a lesser extent with increasing liquid flow rate. The gas holdup can be separated into a dynamic gas holdup , only weakly dependent on packing size and associated with bubbles rising up the bed, and a 'static' holdup which refers to locations within the bed associated with temporally-invariant gas holdup , over the measurement times of 512 s, associated either with gas trapped within the void structure of the bed or with gas channels within the bed. This 'static' gas holdup is strongly dependent on packing size, showing an increase with decreasing packing size. The dynamic gas holdup is comprised of small bubbles-of order of the packing size-which have rise velocities of 10-40 mm s-1 and which move between the packing elements within the bed, along with much larger bubbles, or agglomerates of bubbles, which move with higher rise velocities (100-300 mm s-1). These 'larger' bubbles, which may exist as streams of smaller bubbles or 'amoeboid' bubbles, behave as a single large bubble in terms of the observed high rise velocity. Elongation of the bubbles in the direction of flow was observed for all packings.

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Interfacial area for concurrent gas–liquid upflow through packed bed

Cited by 4 publications

References 15 publications

Packing Size Effect on the Mean Bubble Diameter in a Fixed Bed under Gas–Liquid Concurrent Upflow

Packing Size Effect on the Mean Bubble Diameter in a Fixed Bed under Gas–Liquid Concurrent Upflow

Hydrodynamics and mass transfer enhancement of gas–liquid flow in micropacked bed reactors: Effect of contact angle

Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

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