Enhanced mass transfer from the installation of a sieve tray subject to the variation of liquid heights and flow regimes in a bubble column

Im, Hanjin; Lee, Shinbeom; Lee, Jae Woo

doi:10.1016/j.cherd.2018.05.045

Cited by 10 publications

(9 citation statements)

References 32 publications

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“…A big difference between gas holdup and liquid-side mass transfer coefficient is present with the bubble diameter. If a gas slug or gas cap is created in a bubble column, liquid-side mass transfer is significantly reduced, although gas holdup is not affected a lot . Because the gas slug or gas cap cannot be created in this work, the transitional superficial gas velocity was similar with the four different analysis methods.…”

Section: Resultsmentioning

confidence: 89%

“…After the complete replacement of the system gas by oxygen, the object gas was distributed, and the variation of DO in the system liquid was measured using a polarographic DO meter (Hanna Instruments, HI98193). The collected DO data were transferred to the PC, and the experimental k l a was calculated by the following equation 36,46,47 Bubble velocity was measured by a stopwatch. Once a bubble was released above the sparger, exact time measurement began.…”

Section: Methodsmentioning

confidence: 99%

“…If a gas slug or gas cap is created in a bubble column, liquid-side mass transfer is significantly reduced, although gas holdup is not affected a lot. 36 Because the gas slug or gas cap cannot be created in this work, the transitional superficial gas velocity was similar with the four different analysis methods. Thus, the average of the transition regime velocities was employed to propose a correlation of the transitional superficial gas velocity in the following section.…”

Section: Volumetric Mass Transfer Coefficient (K L A)mentioning

confidence: 99%

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Prediction of Main Regime Transition with Variations of Gas and Liquid Phases in a Bubble Column

Park

Lee

2019

ACS Omega

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Industrial bubble columns mainly operate in a heterogeneous flow regime and identifying transition from homogeneous to heterogeneous flow is important. This work addresses the determination of flow regimes with gas–liquid systems in a bubble column. Various parameters of gas holdup, volumetric mass transfer coefficient, drift flux, and pressure standard deviations were investigated to precisely determine the superficial gas velocity at the transition regime. For a column aspect ratio ( H / D : static liquid height to column diameter ratio) of 2.5 to 5, the transitional superficial gas velocity generally became higher with lower liquid height. However, the reverse trend was observed with a low density gas system due to the difference in force balance acting around the bubble. The weak body force and drag force in a lower axial position interrupted the mass transfer process. The experimental results showed similar ranges of the transitional superficial gas velocity regardless of the choice of parameter for detecting it. Because there is no precise correlation about transition regime properties, we proposed new correlations to predict both transition regime superficial gas velocity and gas holdup by taking the intersection of the two regimes. The correlations precisely captured the transition regime properties within 15% deviations even in gas–liquid systems that are not tested in this work.

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Section: Resultsmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Volumetric Mass Transfer Coefficient (K L A)mentioning

confidence: 99%

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Prediction of Main Regime Transition with Variations of Gas and Liquid Phases in a Bubble Column

Park

Lee

2019

ACS Omega

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“…A mass transfer enhancement can be safely realized by increasing the gas-liquid interfacial area. 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.…”

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

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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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“…Figure 4A shows the η SO2 at different pore diameters (d h = 5, 10, and 15 mm) with a nearly constant porosity (φ 0 ≈ 0.3). According to the curve, the η SO2 values at d h = 5 mm were much higher than those at other d h values because pores with smaller diameters can disperse the continuous flow of gas into smaller bubbles (Im et al, 2018), which can enlarge the contact area of the gas and liquid. Furthermore, the changes in η SO2 at d h = 15 and 25 mm were not obvious, which illustrates that the bubbles may be too large to impact the mass transfer of the sieve tray.…”

Section: Impact Of Gas Flow Ratesmentioning

confidence: 96%

Enhanced Efficiency of the Sieve Tray in a Desulfurization Spray Scrubber

Mengli

et al. 2022

Front. Energy Res.

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The wet flue gas desulfurization (WFGD) system is widely used in coal-fired power plants worldwide. Improving its efficiency is very important for economical running. In this study, SO2 removal by the spray scrubber by adding a new sieve tray was studied and compared to that by the traditional spray scrubber without a sieve tray (the WFGD system). The effects of gas flow rate, liquid flow rate, inlet SO2 concentration, and pH value on both types of scrubbers were evaluated. Pore diameter and porosity of the sieve tray in the sieve-tray spray scrubber were determined, and its enhanced efficiency under different experimental conditions was calculated. The results showed that the enhanced efficiency increased with the increasing liquid flow rate, gas flow rate under the same liquid/gas ratio (L/G), and pH value. Compared to the spray scrubber without a sieve tray, the sieve-tray spray scrubber had significantly higher efficiency. The enhanced efficiencies were mostly between 20% and 60% in the experimental range.

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Enhanced mass transfer from the installation of a sieve tray subject to the variation of liquid heights and flow regimes in a bubble column

Cited by 10 publications

References 32 publications

Prediction of Main Regime Transition with Variations of Gas and Liquid Phases in a Bubble Column

Prediction of Main Regime Transition with Variations of Gas and Liquid Phases in a 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

Enhanced Efficiency of the Sieve Tray in a Desulfurization Spray Scrubber

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