Mathematische Modellierung von Wirbelschichtreaktoren

Mathematical modelling of fluidized bed reactors . Among the many fluidized bed models to be found in the literature, the two‐phase model originally proposed by May has proved most suitable for accommodation of recent advances in flow mechanics: this model resolves the gas/solids fluidized bed into a bubble phase and a suspension phase surrounding the bubbles. Its limitation to slow reactions is a disadvantage. On the basis of the analogy between fluidized beds and gas/liquid systems, a general two‐phase model that is valid for fast reactions has therefore been developed and its validity is confirmed by comparison with the experimental results obtained by other authors. The model describes mass transfer across the phase interface with the aid of the film theory known from gas/liquid reactor technology, and the reaction occurring in the suspension phase as a pseudo‐homogeneous reaction. Since the dependence of the performance of fluidized bed reactors upon geometry is accounted for, the model can also be used for scale‐up calculations. Its use is illustrated with the aid of design diagrams.