Gas hold-up and bubble diameters in a gassed oscillatory baffled column

Oliveira, Mónica; Ni, Xiongwei

doi:10.1016/s0009-2509(01)00257-3

Cited by 43 publications

(70 citation statements)

References 10 publications

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“…Furthermore, it is seen that the influence of gas holdup on k L a is stronger than that of bubble size. This is in qualitative agreement with our previous study [25], although the values of the exponents are slightly different. The discrepancy can be attributed to the fact that the previous analysis was performed using empirical correlations based on experimental data obtained in different geometrical and operating conditions.…”

Section: Resultssupporting

confidence: 93%

Effect of hydrodynamics on mass transfer in a gas–liquid oscillatory baffled column

Oliveira

2004

Chemical Engineering Journal

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In this paper, we present an experimental study on mass transfer of oxygen into water in an oscillatory baffled column (OBC). The objective of this work is to establish the contribution of individual parameters, such as the size of bubbles and the gas holdup, to the overall volumetric mass transfer coefficient (k L a). Our results show that the gas holdup is the most important factor. The liquid-side mass transfer coefficient (k L ) is calculated directly from the experimental measurements of gas holdup, Sauter mean diameter and k L a, and an increase of k L with D 32 is observed. The results also show that, above a critical level of fluid oscillation, the mass transfer coefficients are mainly governed by the oscillatory operating conditions, while independent of the type of gas sparger.

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Section: Resultssupporting

confidence: 93%

Effect of hydrodynamics on mass transfer in a gas–liquid oscillatory baffled column

Oliveira

2004

Chemical Engineering Journal

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“…At a power density of 100 W m 23 , intense mixing conditions are produced in both reactor types. However, the k L a value produced in the OBR is approximately 75 per cent higher than the STR: predominantly a result of enhanced gas hold-up time but also reduced bubble diameter [52]. The unique fluid mechanics in OBRs produce a longer path length for individual gas bubbles, thereby increasing gas hold-up, by increasing each bubble's residence time.…”

Section: Enhanced Mass Transfermentioning

confidence: 92%

Biological processing in oscillatory baffled reactors: operation, advantages and potential

Harvey

et al. 2013

Interface Focus.

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The development of efficient and commercially viable bioprocesses is essential for reducing the need for fossil-derived products. Increasingly, pharmaceuticals, fuel, health products and precursor compounds for plastics are being synthesized using bioprocessing routes as opposed to more traditional chemical technologies. Production vessels or reactors are required for synthesis of crude product before downstream processing for extraction and purification. Reactors are operated either in discrete batches or, preferably, continuously in order to reduce waste, cost and energy. This review describes the oscillatory baffled reactor (OBR), which, generally, has a niche application in performing ‘long’ processes in plug flow conditions, and so should be suitable for various bioprocesses. We report findings to suggest that OBRs could increase reaction rates for specific bioprocesses owing to low shear, good global mixing and enhanced mass transfer compared with conventional reactors. By maintaining geometrical and dynamic conditions, the technology has been proved to be easily scaled up and operated continuously, allowing laboratory-scale results to be easily transferred to industrial-sized processes. This is the first comprehensive review of bioprocessing using OBRs. The barriers facing industrial adoption of the technology are discussed alongside some suggested strategies to overcome these barriers. OBR technology could prove to be a major aid in the development of commercially viable and sustainable bioprocesses, essential for moving towards a greener future.

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“…Many researchers implicitly make this assumption without examining the higher order statistics, primarily due to the challenge of generating a sufficiently large sample size to accurately estimate the higher order statistics. Sauter mean diameter (d 32 ) is the most widely used characteristic length in bubble column studies (e.g., [2][3][4][5]). Sauter mean diameter,…”

Section: Introductionmentioning

confidence: 99%

Characterization of Bubble Size Distributions within a Bubble Column

Mohagheghian

Elbing

2018

Fluids

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Abstract:The current study experimentally examines bubble size distribution (BSD) within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63-102 mm), injection tube diameter (0.8-1.6 mm) and superficial gas velocity (1.4-55 mm/s) were varied. Large samples (up to 54,000 bubbles) of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs). The PDFs were used to identify an alternative length scale termed the most frequent bubble size (d mf ) and defined as the peak in the PDF. This length scale as well as the traditional Sauter mean diameter were used to assess the sensitivity of the BSD to gas injection rate, injector tube diameter, injection tube angle and column diameter. The d mf was relatively insensitive to most variation, which indicates these bubbles are produced by the turbulent wakes. In addition, the current work examines higher order statistics (standard deviation, skewness and kurtosis) and notes that there is evidence in support of using these statistics to quantify the influence of specific parameters on the flow-field as well as a potential indicator of regime transitions.

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Gas hold-up and bubble diameters in a gassed oscillatory baffled column

Cited by 43 publications

References 10 publications

Effect of hydrodynamics on mass transfer in a gas–liquid oscillatory baffled column

Effect of hydrodynamics on mass transfer in a gas–liquid oscillatory baffled column

Biological processing in oscillatory baffled reactors: operation, advantages and potential

Characterization of Bubble Size Distributions within a Bubble Column

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