Oxygen transfer in hydrocarbon–aqueous dispersions and its applicability to alkane bioprocesses: A review

Volumetric mass transfer coefficients characterising VOC absorption in water/silicone oil mixtures

“…To date, although the results reported in the literature were not able to lead to an accurate conclusion about the influence of this coefficient on the mass transfer pathway [5], it is assumed that the most probable mass transfer pathway should be in series for beading oils. Hence, in our opinion the results presented in this study give a valuable contribution to the mass transfer mechanisms which remains still disputed [13]. To summarise this interpretation of toluene absorption, it can be said that the time needed to reach equilibrium increases with φ because, on the one hand, the absorption capacity of the mixture increases with φ and, on the other hand, while water remains the continuous liquid phase, its presence is a barrier to the mass transfer.…”

“…The mass transfer mechanism depends upon the dynamics of the system in which it occurs [12] but, in the case of TPPBs, the K L a change due to the addition of a nonaqueous phase (NAP) to the aqueous phase seems difficult to predict. By so doing, an extensive review devoted to oxygen transfer in hydrocarbon-aqueous dispersions [13] has highlighted the need to address the complexities of the volumetric mass transfer coefficient in TPPBs. Moreover, methods for mass transfer measurement must be carefully considered.…”

Methane degradation in two-phase partition bioreactors

“…With respect to the mass transfer increase, no consistent relation has been found between the volumetric mass transfer (k L a) and organic phase addition as reported by Clarke and Correia [22]. For silicone oil, Morao et al [23] reported that there is a "critical fraction" from which an improvement in k L a may be obtained.…”

Ionic liquids: Applications and future trends in bioreactor technology

“…Nonetheless, despite the reduction of viscosity in the presence of water, ILs are still more viscous than other organic solvents used up to now in multiphase reactors. For instance, [BMIM] [PF 6 ] is 20, 12 and 3 times more viscous than n-hexadecane, Flutec P66 (perfluorocarbon) and silicone oil 20 cSt, respectively (Clarke and Correia, 2008;Quijano et al, 2009b). Additionally, IL viscosity is affected by the alkyl chain length, an increase in the viscosity being observed with an increase in the chain length.…”

“…It is well known that the addition of highlyviscous liquids to bioreactors can lead to mass transfer limitations and high power input requirements (Clarke and Correia, 2008;Galaction et al, 2004). Therefore, a decrease in the alkyl chain length may improve the IL performance in terms of biocompatibility, mass transfer and energy requirements.…”