Mass transfer and hydrodynamic characteristics of loop reactors with downflow liquid jet ejector

Dutta, Narendra Nath; Raghavan, K. V.

doi:10.1016/0300-9467(87)80049-7

Cited by 73 publications

(50 citation statements)

References 11 publications

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“…The powers of P/V and U G were found to be different compared with those proposed for mechanically stirred vessels 12 and bubble columns. 17,22 These differences may be attributed to the contactor type, contact mode and operating conditions. In addition, since gas utilization and new bubble formation is fairly high in our study, the proportionality constants and exponents in the equations are very different from other contactors.…”

Section: Resultsmentioning

confidence: 97%

Gas–liquid interfacial area and mass transfer coefficient in a co‐current down flow contacting column

Dursun

Akosman

2006

J of Chemical Tech & Biotech

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The gas-liquid interfacial area and mass transfer coefficient for absorption of oxygen from air into water, aqueous glycerol solutions up to 1.5% (w/w) and fermentation medium containing glucose up to a 3% concentration were determined in a co-current down flow contacting column (CDCC; 0.05 m i.d. and 0.8 m length). Experimental studies were conducted using various nozzle diameters at different gas and re-circulation liquid rates. Specific interfacial area (a) is determined from the fractional gas hold-up (ε G ) and the average bubble diameter (d b ). Once the interfacial area is determined, the volumetric mass transfer coefficient (k L a) is then used to evaluate the film mass transfer coefficient in the CDCC. The effects of operating conditions and liquid properties on the specific interfacial area were investigated. The values of interfacial area in air-aqueous glycerol solutions and fermentation media were found to be lower than those in the air-water system. As far as experimental conditions were concerned, the values of interfacial area obtained from this study were found to be considerably higher than those of the literature values of conventional bubble columns. The penetration theory is used to interpret the film mass transfer coefficient and results match the experimental k L data reasonably well.  2006 Society of Chemical IndustryKeywords: co-current down flow contacting column (CDCC); interfacial area; mass transfer; mass transfer coefficient; fermentation medium

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Section: Resultsmentioning

confidence: 97%

Gas–liquid interfacial area and mass transfer coefficient in a co‐current down flow contacting column

Dursun

Akosman

2006

J of Chemical Tech & Biotech

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“…At higher gas flow rates a transition from bubble flow to jet flow took place and the transition occurred at a volumetric ratio of gas to liquid flow of approximately 1.3. Dutta and Raghavan (1987) reported the transition in down-flow ejectors occurred at 0.65. Actually, in our previous work (Yao et al, 2008), it was found that the different flow regimes coexisted for the gas-liquid two phase in the up-flow ejector.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of Gas-Liquid Flow Field in Up-Flow Ejectors with and without Swirl

Yao

Guo

Zhou

2009

J. Chem. Eng. Japan

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“…The gas-liquid contacting devices with an ejector-type of gas distribution, utilizing the kinetic energy of a high velocity liquid jet in order to entrain and disperse the gas phase, have become of interest in recent years. 1 Most of the studies concerning continuous systems have gas dispersed from the bottom with liquid flowing either counter-currently or co-currently to the gas phase. One of the major disadvantages of such systems is the limitation of the gas phase residence time, which arises due to the rise velocity of the bubbles.…”

Section: Introductionmentioning

confidence: 99%

“…2 The co-current downflow bubble column is a novel gas-liquid contactor developed initially by Boyes and Ellis 3 and it has been proved to offer better mass transfer performance than that of not only conventional bubble columns but also of stirred reactors for multiphase absorption systems. [4][5][6] The advantages of the co-current downflow bubble column include: (1) little maintenance due to their simple construction, (2) small operating volume, (3) simplicity in operation due to no moving parts, (4) low gas feed rate, (5) effective gas utilization (ie 100% total absorption of gas) and (6) efficient inter-phase mass transfer rate at low energy input.…”

Section: Introductionmentioning

confidence: 99%

Mass transfer and hydrodynamic characteristics in a co‐current downflow contacting column

Dursun

Orhan

Akosman

2003

J of Chemical Tech & Biotech

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Hydrodynamic and mass transfer characteristics of water-air system in a co-current downflow contacting column (CDCC) were studied for various nozzle diameters at different superficial gas velocities and liquid re-circulation rates. Gas hold-up and liquid-side mass transfer coefficient increased with increasing superficial gas velocity and liquid flow rate but decreased with increasing nozzle diameter. It is shown that correlations developed, which are based on liquid kinetic power per liquid volume present in the column, and superficial gas velocity explains gas hold-up and the mass transfer coefficient within an error 20% for all gas and liquid flow rates and nozzle diameters used. The constants of correlations for gas hold-up and mass transfer coefficient were found to be considerably different from other gas-liquid contacting systems. # 2003 Society of Chemical Industry Keywords: gas hold-up; mass transfer; k L a; co-current downflow contacting column (CDCC); correlation

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Mass transfer and hydrodynamic characteristics of loop reactors with downflow liquid jet ejector

Cited by 73 publications

References 11 publications

Gas–liquid interfacial area and mass transfer coefficient in a co‐current down flow contacting column

Gas–liquid interfacial area and mass transfer coefficient in a co‐current down flow contacting column

Experimental Measurement of Gas-Liquid Flow Field in Up-Flow Ejectors with and without Swirl

Mass transfer and hydrodynamic characteristics in a co‐current downflow contacting column

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