Modeling Growth Rates in Static Layer Melt Crystallization

Abstract

The prediction of growth rates as functions of process conditions can reduce experimental efforts to develop crystallization processes. There is a lack of reliable models of static layer melt crystallization in the literature. In this study, a model for the prediction of growth rates for static layer melt crystallization was developed. The essence of this model is the description of heat transport during crystal growth in a naturally convected static melt where, in contrast to other models, the implicit relation between the growth rate and the natural convection is considered. Predicting crystal growth rates requires knowledge of the crystal thermal conductivity, a sensitive physical property that is often estimated or fit to experimental data. In this study, an approach for measuring the crystal thermal conductivity was developed and successfully validated with literature data. The crystal thermal conductivities of p-xylene, n-hexadecane, n-dodecanal, and n-tridecanal were measured. With the use of these measurements, the crystal growth rates of the binary systems n-dodecanal/iso-dodecanal, n-tridecanal/iso-tridecanal, and p-xylene/m-xylene from static layer crystallization were predicted as functions of the process conditions. Good agreement with experimental data was achieved without the use of a fitted parameter.