Prediction of the zeolite crystal size distribution in batchwise hydrothermal synthesis

Abstract

Several ways of characterizing the crystal size distribution during batchwise hydrothermal synthesis of molecular sieve zeolites are shown. In particular, we show how the crystal size distribution function can be predicted once the transient birth rate and growth rate functions have been determined, and how average size, standard deviation, and skewness can be used to characterize the size distribution. Simulation results are presented which show the effect of manipulating several key parameters in the synthesis system (e.g. initial reagent concentration and nucleation rate). It is shown how one might change the operating policy of the batch crystallizer to obtain larger particle sizes and/or narrower crystal size distribution.