Sparger Type Influence on the Volumetric Mass Transfer Coefficient in the Draft Tube Airlift Reactor with Diluted Alcohol Solutions

Šijački, Ivana M.; Tokic, Milenko; Kojić, Predrag; Petrović, Dragan Lj.; Tekić, Miodrag N.; Lukić, Nataša

doi:10.1021/ie303211u

Cited by 11 publications

(8 citation statements)

References 32 publications

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“…The results are commented with respect to the external loop airlift reactor of the same geometry, but without membrane in the downcomer. Furthermore, this study tends to broaden the previous investigations on mutual influence of added alcohol and the gas sparging effectiveness on the hydrodynamics and the mass transfer in the airlift reactors [26,27].…”

mentioning

confidence: 91%

Volumetric gas-liquid mass transfer coefficient in an external-loop airlift reactor with inserted membrane

Kojić

Šijački

Lukić

et al. 2016

CI&CEQ

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The effects of the inserted membrane in the downcomer of an external-loop airlift reactor, the gas sparger type (single orifice and sinter plate) and added alcohol (ethanol, n-butanol, or n-hexanol) on the volumetric gas-liquid mass transfer coefficient (kLa) were studied. Due to the presence of the membrane in the downcomer, kLa did not change significantly; the differences were smaller than 10%. The highest values of the kLa were obtained using the sinter plate. It was found that the addition of small amounts of alcohol increased the mass transfer. Using our experimental results and the data of other authors, the feed-forward back propagation neural network for prediction of kLa in external-loop airlift reactors with alcohol solutions was proposed. [Projekat Ministarstva nauke Republike Srbije, br. 172025]

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mentioning

confidence: 91%

Volumetric gas-liquid mass transfer coefficient in an external-loop airlift reactor with inserted membrane

Kojić

Šijački

Lukić

et al. 2016

CI&CEQ

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“…A minimum ethanol concentration of 0.46% was employed here. In a previous study, this concentration was found to be the minimal amount required to noticeably influence bubble size [60]. In some experiments, large mass fractions of ethanol were used, and therefore fluid mixture properties were affected as shown in Table 1.…”

Section: Modulation Of Interfacial Surface Tensionmentioning

confidence: 93%

Experimental investigation of the effect of ethyl alcohol surfactant on oxygen mass transfer and bubble size distribution in an air-water multiphase Taylor-Couette vortex bioreactor

Ramezani

Legg

Haghighat

et al. 2017

Chemical Engineering Journal

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Volumetric liquid side mass transfer, bubble size distribution, and bubble shape was measured in a vertically oriented semi-batch gas-liquid Taylor-Couette vortex reactor with an aspect ratio of Γ=h/(r o -r i )=40 and radius ratio of η=r i /r o =0.75. Azimuthal Reynolds number, Axial Reynolds number and Capillary number were varied between 0 to 3.8×10 4 , 7 to 99, and 6.1×10 -6 to 76.0×10 -6 , respectively. Power-law correlations based on these data were presented for dimensionless Sauter mean diameter and Sherwood number in terms of the dimensionless parameters. Presence of ethanol as surfactant in the liquid was shown to inhibit bubble coalescence, which in addition to lowering interfacial surface tension causes a generally smaller bubble size at higher concentrations of surfactant. It was also shown that the mass transfer coefficient generally increases with higher concentrations of surfactant. Both the bubble diameter and mass transfer are influenced more at lower concentrations of surfactant, and the introduction of higher amount of ethanol causes a decrease in both parameters. Keywords Gas-liquid mass transfer, Surfactant, Sherwood number, Taylor-Couette vortex bioreactor.  The addition of surfactant decreases bubble size Nomenclature Roman a Specific gas-liquid interfacial surface area [m 2 /m 3 ] C Concentration [mg/L] d Bubble diameter [mm] D Diffusion coefficient [m 2 /s] E Ellipticity of spheroid g Gravitational acceleration [m/s 2 ] h Axial distance from the bottom of reactor [m] k Volumetric mass transfer coefficient [m/s] l Spheroid major diameter [m] m Spheroid minor diameter [m] N Impeller (inner cylinder) rotational speed [rev/s] Q Volumetric flow rate [L/min] r i Outer radius of the inner cylinder [m] r o Inner radius of the outer cylinder [m] u Superficial velocity [m/s] Greek Γ Reactor aspect ratio (Γ=h/(r o -r i )) ε G Gas holdup η Reactor radius ratio (η=r i /r o ) ω Rotational speed of the inner cylinder [rad/s]

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“…To apply the model that covers the whole range of ELAR sizes (see Tab. 2), the geometrical parameter A d /A r must be included. In previous investigations, we successfully fitted experimental values with these parameters by using correlations [4,12,13,37]. The general form of the applied power law correlations was:…”

Section: Correlationmentioning

confidence: 99%

“…Freitas and Teixeira [10] and Miyahara and Nagatani [5] found that the only property of alcohol solutions that differed considerably from water was their surface tension. Also, it was observed that the gas holdup, and therefore the mass transfer coefficient, increased with increasing number of carbons in the alcohols and the concentration of the alcohols [11][12][13]. Further, alcohol solutions have been used to simulate the liquid phase in coal liquefaction and in bioreactors due to the presence of non-coalescing organic mixtures [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Sparger Type and Added Alcohol on the Gas Holdup of an External‐Loop Airlift Reactor

et al. 2015

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The influences of alcohol adding and three different gas spargers (single orifice, perforated plate, and sinter plate) on the gas holdup in an external-loop airlift reactor were studied. The experimental results show that the gas holdup can be increased by mutual influence of both the alcohol adding and the sparger type. The presence of small amounts of normal aliphatic alcohols caused an increase of the gas holdup compared to the air-water system, due to their coalescence-inhibiting nature. The sinter plate was the most efficient sparger, followed by the perforated plate and the single orifice. A proposed artificial neural network (ANN) has the potential to predict gas holdup values in airlift reactors for various alcohols and types of gas spargers.

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Sparger Type Influence on the Volumetric Mass Transfer Coefficient in the Draft Tube Airlift Reactor with Diluted Alcohol Solutions

Cited by 11 publications

References 32 publications

Volumetric gas-liquid mass transfer coefficient in an external-loop airlift reactor with inserted membrane

Volumetric gas-liquid mass transfer coefficient in an external-loop airlift reactor with inserted membrane

Experimental investigation of the effect of ethyl alcohol surfactant on oxygen mass transfer and bubble size distribution in an air-water multiphase Taylor-Couette vortex bioreactor

Influence of the Sparger Type and Added Alcohol on the Gas Holdup of an External‐Loop Airlift Reactor

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