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International Journal of Chemical Engineering
Volume 2012 (2012), Article ID 265603, 7 pages
http://dx.doi.org/10.1155/2012/265603
Research Article

Oxygen Absorption into Stirred Emulsions of n-Alkanes

Institut für Technische Chemie, Technische Universität Braunschweig, Hans-Sommer-Straße 10, 38106 Braunschweig, Germany

Received 21 March 2012; Revised 5 June 2012; Accepted 5 June 2012

Academic Editor: Jose Teixeira

Copyright © 2012 Thanh Hai Ngo and Adrian Schumpe. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Absorption of pure oxygen into aqueous emulsions of n-heptane, n-dodecane, and n-hexadecane, respectively, has been studied at 0 to 100% oil volume fraction in a stirred tank at the stirring speed of 1000 min−1. The volumetric mass transfer coefficient, π‘˜ 𝐿 π‘Ž , was evaluated from the pressure decrease under isochoric and isothermal (298.2 K) conditions. The O/W emulsions of both n-dodecane and n-hexadecane show a π‘˜ 𝐿 π‘Ž maximum at 1-2% oil fraction as reported in several previous studies. Much stronger effects never reported before were observed at high oil fractions. Particularly, all n-heptane emulsions showed higher mass-transfer coefficients than both of the pure phases. The increase is by upto a factor of 38 as compared to pure water at 50% n-heptane. The effect is tentatively interpreted by oil spreading on the bubble surface enabled by a high spreading coefficient. In W/O emulsions of n-heptane and n-dodecane π‘˜ 𝐿 π‘Ž increases with the dispersed water volume fraction; the reason for this surprising trend is not clear.