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This paper takes a look on the effects of mass transport limitation occurring in hydrolysis of rape seed oil by means of an interfacial activated lipase from Thermomyces lanuginosus. In order to carry out investigations for process optimization, the slug flow reactor was chosen in which a large interfacial area can be generated and the mass transport can be investigated individually for each phase. The choice of the capillary material determines the dispersed and the continuous phase. As shown by computational fluid dynamics simulation, the continuous phase is well mixed due to wall effects. The mixing patterns in the dispersed phase differ due to viscous forces between the phases. It was found that, at the same fluid velocities, the conversion in the glass capillary is higher than in the PTFE capillary. The surface-specific hydrolysis rate is used for comparison purposes, since the properties of the capillary are different. Increasing the velocity, the hydrolysis rate can be considerably increased in comparison to stagnant conditions. Already at a fluid velocity of 1 mm s−1, the hydrolysis rates increased to 2.3-fold in the glass capillary and moreover by a factor of 4 in the PTFE capillary. [ABSTRACT FROM AUTHOR]

Abstract: A new discrete model was developed for the design and analysis of catalytic trickle bed reactors operating in the low interaction regime based on the local structure of packed beds. By detailed comparisons of model predictions to experimental data the performance of the new model is demonstrated. By means of this model the steady-state behavior of trickle bed reactors can be studied in terms of operating conditions, physical properties of all three phases, transport parameters and isothermal reaction kinetics on a particle as well as on a reactor scale. [Copyright &y& Elsevier]

Abstract: A discrete 3D model has been developed for the prediction of static liquid holdup in cylindrical packed beds of spheres incorporating the local structural properties of the packing. The model predictions have been compared to experimental data covering a wide range of relevant physical properties of liquid–solid systems for aspect ratios between 3.5 and 25. A notably good agreement between prediction and experiments is observed. [ABSTRACT FROM AUTHOR]

In order to represent radial dispersion phenomena in packed beds a three-dimensional network model is proposed based on characteristic structural properties of the packing. As shown by a detailed sequential experimental study, the model is able to predict radial Peclet numbers for the turbulent regime in good agreement with experimental data without adjusting any model parameter. [Copyright &y& Elsevier]

Abstract: A new pseudo-continuous model, describing the fluid flow through packed bed reactors, is developed by formulating the Navier–Stokes equations for a statistically described domain geometry. A coupling term, occurring in the momentum equation, represents the fluid–solid interaction and is modelled by comparison with the exact Navier–Stokes equations. Static and dynamic, inviscid and viscous contributions are separated, and stringent requirements for the dependence on the local voidage are found which are met by a simple model. Good agreement with correlations and experiments is found for the predictions of the pressure drop and the radial distribution of the axial velocity. [Copyright &y& Elsevier]