Effects of surfactants on hydrodynamics and mass transfer in a split‐cylinder airlift reactor |
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Authors: | Mostafa Keshavarz Moraveji Mohamad Morovati Pasand Reza Davarnejad Yusuf Chisti |
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Affiliation: | 1. Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak 38156‐8‐8349, Iran;2. School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand |
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Abstract: | Effects of various concentrations (0–5 ppm) of anionic (sodium dodecyl sulfate, SDS) and non‐ionic (Tween‐80 and Triton X‐405) surfactants on gas hold‐up and gas–liquid mass transfer in a split‐cylinder airlift reactor are reported for air–water. Surfactants were found to strongly enhance gas hold‐up. Non‐ionic surfactants were more effective in enhancing gas hold‐up compared to the anionic surfactant SDS. An enhanced gas hold‐up and a visually reduced bubble size in the presence of surfactants implied an enhanced gas–liquid interfacial area for mass transfer. Nevertheless, the overall gas–liquid volumetric mass transfer coefficient was reduced in the presence of surfactants, suggesting that surfactants greatly reduced the true liquid film mass transfer coefficient and this reduction outweighed the interfacial area enhancing effect. Presence of surfactants did not substantially affect the induced liquid circulation rate in the airlift vessel. |
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Keywords: | airlift reactor surfactants gas– liquid mass transfer gas hold‐up liquid circulation |
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