Efficient Control of Microbubble Properties by Alcohol Shear Flows in Ceramic Membrane Channels

Liu, Yefei; Han, Yang; Li, Xiaoli; Jiang, Hong; Chen, Rizhi

doi:10.1002/ceat.201700226

Cited by 20 publications

(20 citation statements)

References 28 publications

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“…5(a), it is clear that the majority of the bubbles generated by the CMM were spherical owing to the surface tension. 26,62 As the cross liquid velocity increased, shear stress increased; thus the bubbles became smaller and more uniform. As indicated in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…For example, by adding internals [18][19][20][21] or changing operation conditions, [22][23][24] the bubble diameter can be effectively decreased, and thus the interfacial area increased. Alcohols, 25,26 surfactants 8,[27][28][29] and electrolytes [30][31][32] are typically added in coalescence systems to inhibit bubble coalescence 33 and increase bubble rigidity, 34 by which bubbles become smaller and a larger interfacial area is obtained. When the bubble size decreases to several micrometers (i.e., microbubbles [35][36][37] ), they exhibit unique properties, 38 e.g.…”

Section: Introductionmentioning

confidence: 99%

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Effects of bubble size on the gas–liquid mass transfer of bubble swarms with Sauter mean diameters of 0.38–4.88 mm in a co‐current upflow bubble column

Wang

Guo

Liu

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND: Bubble columns have found a wide range of application in biochemical industry. Mass transfer in the bubble column can be manipulated by adjusting the bubble size. Thus, for the design of bubble columns, it is necessary to investigate the behaviors of different-sized bubbles. This work attempts to study the global hydrodynamic and mass transfer characteristics of bubble swarms with Sauter mean diameters (d 32) of 0.38-4.88 mm, from microbubbles to millimeter-sized bubbles, in a co-current bubble column. RESULTS: The specific interfacial areas of the bubble swarms with d 32 of 0.38-1.47 (generated by ceramic membrane module) and 1.05-4.88 mm (generated by plate gas distributor) are 250-1100 and 7-270 m −1 , respectively. The liquid-side mass transfer coefficient (k L) of those two kinds of bubbles are (0.45-1.16) × 10 −4 and (0.58-7.65) × 10 −4 m s −1 , respectively. CONCLUSION: Decreasing the bubble size can effectively increase the volumetric mass transfer coefficient (k L a), especially when the bubble size decreases to several micrometers. The major contribution to the mass transfer enhancement results from the increase of the specific interfacial area. Conversely, the k L decreases clearly. It is demonstrated that Higbieʼs and Frosslingʼs equations can approximate the k L of the bubble swarms with d 32 > 2 mm and d 32 < 2 mm in the bubble column, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of bubble size on the gas–liquid mass transfer of bubble swarms with Sauter mean diameters of 0.38–4.88 mm in a co‐current upflow bubble column

Wang

Guo

Liu

et al. 2020

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

show abstract

“…The size of the macrobubble generated from the pipeline is nearly 1 cm. The macrobubble shows a fast rising velocity with a continually deformed shape due to its strong sensitivity to the surrounding flow field . However, the microbubble, generated by the gas distributor, moves sluggishly and shows a stable morphology due to the conspicuous interfacial tension …”

Section: Results and Discussionmentioning

confidence: 99%

“…The macrobubble shows a fast rising velocity with a continually deformed shape due to its strong sensitivity to the surrounding flow field. 29 However, the microbubble, generated by the gas distributor, moves sluggishly and shows a stable morphology due to the conspicuous interfacial tension. 29 The dependences of the mean bubble size on the nitrogen flow rate and the pore size of the distributor (PSD) are shown in Figure 1a.…”

Section: Methodsmentioning

confidence: 99%

Tailoring the Chain Entanglement by Nitrogen Bubble-Assisted Polymerization

Dai

et al. 2021

Ind. Eng. Chem. Res.

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The reduction in the entangled state of the nascent ultrahigh-molecular-weight polyethylene (UHMWPE) is of fundamental importance to enhance its processability and mechanical properties. However, it remains a challenge to retard the formation of entanglements during polymerization above 60 °C because the chain propagation rate is notably higher than the chain crystallization rate. Herein, we present a feasible method for synthesizing the weakly entangled polyethylene via nitrogen microbubble-assisted polymerization. The mass transfer of ethylene inside the growing polyethylene particles is found to dominate the chain propagation process, which is influenced by the nitrogen bubble size. The contact/interval time (10–3 s) between the microbubbles and the particles, observed by a high-speed camera, appears several orders less than the chain propagation time. Consequently, such frequent contact/separation instantly blocks/recovers the reactant transfer on the solvent–particle interphase, causing an intermittent “dormancy effect” to retard the chain propagation and facilitate the chain crystallization. Therefore, the less entangled polyethylene is synthesized at a relatively high activity.

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“…The average diameter of microbubbles was found to significantly decrease with the increase of liquid flow velocity and the decrease of liquid surface tension. 19−21 Liu et al 22 found that liquid viscosity had a dual effect on the size of microbubbles obtained by a multichannel ceramic membrane. With increasing liquid viscosity, the Sauter diameter of microbubbles decreased first (μ < 2 mPa•s) and then increased slowly (2.0 < μ < 20 mPa•s).…”

Section: Introductionmentioning

confidence: 99%

Microbubble Generation in Organic Solvents by Porous Membranes with Different Membrane Wettabilities

Xie

Zhou

Huang

et al. 2021

Ind. Eng. Chem. Res.

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Microbubbles have gained universal interest due to their wide applications in water treatment, cosmetics, and pharmaceutical industry and potential applications in gas–liquid reactions such as hydrogenation and oxidation. However, microbubble formation in organic solvents has been seldom investigated. A controllable and efficient platform is built to investigate microbubble formation in organic solvents using a hydrophilic ceramic membrane and a hydrophobic polytetrafluoroethylene (PTFE) membrane. The effect of membrane wettability on the size of microbubbles is studied with the change of the liquid property and membrane type. Experimental results show that the sizes of microbubbles are in ranges of 130–453 μm and 59–387 μm using the hydrophilic ceramic membrane and the hydrophobic PTFE membrane, respectively. Microbubbles generated in organic solvents using the hydrophilic ceramic membrane are much larger than those in water, and the size of microbubbles formed using the hydrophobic PTFE membrane shows an opposite trend. Furthermore, an equivalent pore is introduced to develop mathematical model to predict the microbubble size, which agrees well with the experimental data.

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Efficient Control of Microbubble Properties by Alcohol Shear Flows in Ceramic Membrane Channels

Cited by 20 publications

References 28 publications

Effects of bubble size on the gas–liquid mass transfer of bubble swarms with Sauter mean diameters of 0.38–4.88 mm in a co‐current upflow bubble column

Effects of bubble size on the gas–liquid mass transfer of bubble swarms with Sauter mean diameters of 0.38–4.88 mm in a co‐current upflow bubble column

Tailoring the Chain Entanglement by Nitrogen Bubble-Assisted Polymerization

Microbubble Generation in Organic Solvents by Porous Membranes with Different Membrane Wettabilities

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