Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator

The impact of contaminants on the gas holdup and mixing characteristics encountered in internal airlift reactors was investigated using a 200 L pilot scale unit equipped with a two-phase transonic sparger capable of generating microbubbles. Small dosages of a cationic surfactant (0–50 ppm of sodium...

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Main Authors: Surya K. Pallapothu, Adel M. Al Taweel
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:International Journal of Chemical Engineering
Online Access:http://dx.doi.org/10.1155/2012/569463
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author Surya K. Pallapothu
Adel M. Al Taweel
author_facet Surya K. Pallapothu
Adel M. Al Taweel
author_sort Surya K. Pallapothu
collection DOAJ
description The impact of contaminants on the gas holdup and mixing characteristics encountered in internal airlift reactors was investigated using a 200 L pilot scale unit equipped with a two-phase transonic sparger capable of generating microbubbles. Small dosages of a cationic surfactant (0–50 ppm of sodium dodecyl sulfonate (SDS)) were used to simulate the coalescence-retarding effect encountered in most industrial streams and resulted in the formation of bubbles that varied in size between 280 and 1,900 μm. Gas holdups as high as 0.14 were achieved in the riser under homogeneous flow regime when slowly coalescent systems were aerated at the relatively low superficial velocity of 0.02 ms−1, whereas liquid circulation velocities as high as 1.3 ms−1 were achieved in conjunction with rapidly coalescent systems at the same superficial velocity. This excellent hydrodynamic performance represents a 5-fold improvement in the riser gas holdup and up to 8-fold enhancement in the liquid circulation velocity and is expected to yield good mixing and mass transfer performance at low energy dissipation rates.
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publishDate 2012-01-01
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spelling doaj-art-d0e090e482084d418cdca32b7e3b5c222025-08-20T02:19:57ZengWileyInternational Journal of Chemical Engineering1687-806X1687-80782012-01-01201210.1155/2012/569463569463Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble GeneratorSurya K. Pallapothu0Adel M. Al Taweel1Multiphase Mixing and Separations Research Laboratory, Department of Process Engineering and Applied Sciences, Dalhousie University, Halifax, NS, B3J 2X4, CanadaMultiphase Mixing and Separations Research Laboratory, Department of Process Engineering and Applied Sciences, Dalhousie University, Halifax, NS, B3J 2X4, CanadaThe impact of contaminants on the gas holdup and mixing characteristics encountered in internal airlift reactors was investigated using a 200 L pilot scale unit equipped with a two-phase transonic sparger capable of generating microbubbles. Small dosages of a cationic surfactant (0–50 ppm of sodium dodecyl sulfonate (SDS)) were used to simulate the coalescence-retarding effect encountered in most industrial streams and resulted in the formation of bubbles that varied in size between 280 and 1,900 μm. Gas holdups as high as 0.14 were achieved in the riser under homogeneous flow regime when slowly coalescent systems were aerated at the relatively low superficial velocity of 0.02 ms−1, whereas liquid circulation velocities as high as 1.3 ms−1 were achieved in conjunction with rapidly coalescent systems at the same superficial velocity. This excellent hydrodynamic performance represents a 5-fold improvement in the riser gas holdup and up to 8-fold enhancement in the liquid circulation velocity and is expected to yield good mixing and mass transfer performance at low energy dissipation rates.http://dx.doi.org/10.1155/2012/569463
spellingShingle Surya K. Pallapothu
Adel M. Al Taweel
Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
International Journal of Chemical Engineering
title Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
title_full Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
title_fullStr Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
title_full_unstemmed Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
title_short Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator
title_sort effect of contaminants on the gas holdup and mixing in internal airlift reactors equipped with microbubble generator
url http://dx.doi.org/10.1155/2012/569463
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AT adelmaltaweel effectofcontaminantsonthegasholdupandmixingininternalairliftreactorsequippedwithmicrobubblegenerator