Numerical study on Taylor flow in monolithic reactors
Tutor / director / evaluatorLange, Rüdiger
Document typeMaster thesis (pre-Bologna period)
Rights accessRestricted access - confidentiality agreement
Monolithic reactors are promising catalyst designs to intensify multiphase (gas-liquid-solid) reaction processes and several investigations have validated its potential concerning space-time yield and selectivity, especially if fast reactions are employed which are controlled by mass transfer. Monoliths are single structures composed of a large number of parallel straight flow channels, often in a honeycomb arrangement. The essential advantage of such a structure is an excellent mass transfer between the heterogeneous phases, due to an intense gas-liquid-solid contact and short diffusion distances. In theoretical investigations several models, which are based on correlations to describe mass transfer and reaction kinetics and differ in their complexity, have been developed to predict the reactor performance. However, further research is needed to reduce the discrepancy between the predicted and experimental results by model modifications which are based on physics. In this work a one-dimensional model that describes the conversion and the selectivity in the hydrogenation of cinnamaldehyde in a single channel of a monolithic reactor has been developed. In contrast to published models in the literature, effects of reduced bubble size due to chemical reactions are included. This leads to a local dependence of all hydrodynamic parameters such as bubble length, unit cell velocity, hold-up and film thickness and all mass transfer parameters such as coefficients and specific interfaces. Investigations of the influence of both the material properties such as dynamic viscosity, density, surface tension, diffusion coefficient and saturation concentration of H2, and the design parameters such as hydraulic diameter, catalyst loading and reactor length, on the reactor performance are discussed in detail. Moreover, the influence of system conditions such as unit cell length, superficial velocities, hold-ups, pressure and temperature, are also discussed. To enhance the developed model, improved correlations that describe mass transfer processes in such structures needs to be developed and crucial material properties, such as diffusion coefficients have to be determined with higher accuracy, since both aspects have a strong influence on the conversion and selectivity of the reaction.
SubjectsHydrogenation, Organic compounds, Catalysts, Chemical reactions, Hidrogenació, Compostos orgànics, Catalitzadors, Reaccions químiques
ProvenanceAquest document conté originàriament altre material i/o programari no inclòs en aquest lloc web
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