Energy efficiency and performance of bubble generating systems

Ansari, Manizheh; Bokhari, Hussain Haider; Turney, Damon E.

doi:10.1016/j.cep.2017.12.019

Cited by 23 publications

(12 citation statements)

References 83 publications

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“…Regarding the question of why the micro‐jet array reactor outperforms an impinging‐jet or ejector reactor, the evidence leads us to consider the length‐scale of decay of turbulence near a jet. Our measurements of the spatial decay of turbulence in the region downstream of the micro‐jet array agree with previous classical fluid dynamics studies of jets insofar as the decay length of a jet scales with the jet diameter . As the bubble breakup mechanism requires only a very small distance to operate, a micro‐jet can perform the same tasks as a macroscopic jet and also avoid unnecessary downstream shear that a macroscopic jet would create downstream.…”

Section: Resultssupporting

confidence: 85%

“…Our measurements of the spatial decay of turbulence in the region downstream of the micro-jet array 8 agree with previous classical fluid dynamics studies of jets insofar as the decay length of a jet scales with the jet diameter. 63,64 As the bubble breakup mechanism requires only a very small distance to operate, a micro-jet can perform the same tasks as a macroscopic jet and also avoid unnecessary downstream shear that a macroscopic jet would create downstream. In other words, the large jet diameter of impinging-jet reactors causes long length scales of turbulence which waste energy and do not contribute to making the bubbles smaller, which explains the lower energy efficiency of impinging-jet reactors and ejectors compared to our new micro-jet array reactor.…”

Section: Spatial Distributions Of Gas Fraction and Bubble Diametermentioning

confidence: 99%

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A micro‐jet array for economic intensification of gas transfer in bioreactors

Turney

Ansari

Kalaga

et al. 2018

Biotechnology Progress

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Bioreactors are of interest for gas‐to‐liquid conversion of stranded or waste industrial gases, such as CO, CH4, or syngas. Process economics requires reduction of bioreactor cost and size while maintaining intense production via rapid delivery of gases to the liquid phase (i.e., high kLa). Here, we show a novel bioreactor design that outperforms all known technology in terms of gas transfer energy efficiency (kLa per power density) while operating at high kLa (i.e., near 0.8 s−1). The reactor design uses a micro‐jet array to break feedstock gas into a downward microbubble flow. Hydrodynamic and surfactant measurements show the reactor's advanced performance arises from its bubble breakage mechanism, which limits fluid shear to a thin plane located at an optimal location for bubble breakage. Power dissipation and kL are shown to scale with micro‐jet diameter rather than reactor diameter, and the micro‐jet array achieves improved performance compared to classical impinging‐jets, ejector, or U‐loop reactors. The hydrodynamic mechanism by which the micro‐jets break bubbles apart is shown to be shearing the bubbles into filaments then fragmentation by surface tension rather than “cutting in half” of bubbles. Guided by these hydrodynamic insights, strategies for industrial design are given. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2710, 2019

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Section: Resultssupporting

confidence: 85%

Section: Spatial Distributions Of Gas Fraction and Bubble Diametermentioning

confidence: 99%

A micro‐jet array for economic intensification of gas transfer in bioreactors

Turney

Ansari

Kalaga

et al. 2018

Biotechnology Progress

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“…24 Several key metrics were proposed to analyze the energy efficiency of bubble generating systems of gas−liquid contacting reactors quantitatively, such as interfacial area density of the output dispersion and the energy necessary to create interfacial area. 25 A micro-jet array bioreactor for gas transfer intensification outperformed all published technologies in relation to energy efficiency while operating at high k L a (near 0.8 s −1 ). 26 Fluidic oscillator-mediated microbubble generation was applied to wastewater treatment plants.…”

Section: ■ Introductionmentioning

confidence: 94%

“…Two-phase pressure drop could be calculated by a newly developed two-phase friction multiplier correlation with the Lockhart–Martinelli method adopted . Several key metrics were proposed to analyze the energy efficiency of bubble generating systems of gas–liquid contacting reactors quantitatively, such as interfacial area density of the output dispersion and the energy necessary to create interfacial area . A micro-jet array bioreactor for gas transfer intensification outperformed all published technologies in relation to energy efficiency while operating at high k L a (near 0.8 s –1 ) .…”

Section: Introductionmentioning

confidence: 99%

“…A microporous diaphragm aerator was developed to decrease the bubble generation diameter and improve microalgal growth in a raceway reactor . The gas required a specific pressure to open the diaphragm, so the energy necessary to create interfacial area and maintain specific k L a value increased, leading to a lower energy efficiency as k L a per power density ( P / V ) . A CO 2 microbubble dissolver was applied in a horizontal tubular photo-bioreactor system .…”

Section: Introductionmentioning

confidence: 99%

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Three-Stage Shear-Serrated Aerator Broke CO₂ Bubbles To Promote Mass Transfer and Microalgal Growth

Cheng

Song

Miao

et al. 2019

ACS Sustainable Chem. Eng.

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A three-stage shear-serrated aerator (TSA) was proposed to break CO2 gas into smaller bubbles through the first-stage shear with horizontal sawteeth, second-stage shear with vertical sawteeth, and third-stage shear with oblique sawteeth on the serrated cylinder and conical head without additional power. The inlet gas flowed through the square throat to generate initial bubbles and then passed through gaps between triangular cones and broke into smaller bubbles at three-stage alternatively permutated sawteeth. The diameter of sheared bubbles at the TSA outlet reduced when side length of square throat decreased and numbers and height of three-stage sawteeth increased. When inclination angle of the aeration head increased from 20 to 60°, the diameter of sheared bubbles first decreased to a valley (inclination angle = 50°) and then increased. Accordingly, the diameter of sheared bubbles at the TSA outlet reduced by 62% to 2.4 mm, which resulted in an increased mass transfer coefficient (by 25.5%) and microalgal biomass yield (by 46.8%) in a raceway reactor.

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Flow behaviors of multiscale bubbles with porous ceramic membrane distributors: Visualization and modeling

et al. 2023

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The distribution of gas‐liquid two‐phase flow is one of the significant effects on heterogeneous catalytic reactions. Ceramic membrane gas distributors (CMGD) were applied in improving gas‐liquid distribution, and flow behavior of gas as dispersed phase in liquid phase was visualized via high‐speed photograph. The average diameters of multiscale bubbles were measured and modeled ranging from 10−5 to 10−2 m. The coalescence and trajectory of bubbles during rising process were observed, and two typical trajectories straight and spiral types were tracked. To inhibit coalescence of bubbles during rising process, internals manufactured by 3D printing were installed in the channel of ceramic membrane. The average bubble size of CMGD decreases 12% from 392 to 345 μm compared with that of the original CMGD. The CMGD with internals enhances the heterogeneous catalytic reaction performance via providing large quantity of stabile multiscale bubbles which could match the porous structure of catalyst.

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Energy efficiency and performance of bubble generating systems

Cited by 23 publications

References 83 publications

A micro‐jet array for economic intensification of gas transfer in bioreactors

A micro‐jet array for economic intensification of gas transfer in bioreactors

Three-Stage Shear-Serrated Aerator Broke CO₂ Bubbles To Promote Mass Transfer and Microalgal Growth

Flow behaviors of multiscale bubbles with porous ceramic membrane distributors: Visualization and modeling

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Energy efficiency and performance of bubble generating systems

Cited by 23 publications

References 83 publications

A micro‐jet array for economic intensification of gas transfer in bioreactors

A micro‐jet array for economic intensification of gas transfer in bioreactors

Three-Stage Shear-Serrated Aerator Broke CO2 Bubbles To Promote Mass Transfer and Microalgal Growth

Flow behaviors of multiscale bubbles with porous ceramic membrane distributors: Visualization and modeling

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Three-Stage Shear-Serrated Aerator Broke CO₂ Bubbles To Promote Mass Transfer and Microalgal Growth