Abstract— In this work the crystallisation of palm oil (a typical melt) is used as a model process and kinetic parameters at different end temperatures and cooling rates were evaluated using three model approaches: two from the traditional melt fractionation, one from the classic solution crystallisation. The objective was to establish critical understanding on the various model approaches and their applications. Differential Scanning Calorimetry (DSC) was used to obtain the melting temperatures, isothermal induction times and enthalpy of the crystallisation for the Fisher-Turnbull and Avrami model evaluations, while turbidity and temperature probes were utilized to generate metastable zone width as a function of cooling rates for the classical Nyvlt model analysis. Our results show that the Fisher-Turnbull and the Nyvlt models are useful in estimating the nucleation rate constants (kn) with reasonable agreement: this unites the model approaches and allows comparison between fat fractionation and solution crystallisation of organics. While the Avrami model is capable of evaluating the growth mechanism of the formed crystals (n) and the overall crystallisation rate constant (k), none of the parameters can be compared with other models because of the different definitions of the growth mechanism as well as the dependence of k value on the growth mechanism when dealing different fats of varying compositions. This is the first contribution of this work. In addition, our results indicate that the growth of nuclei to a stable size was generally slower in melt crystallisation compared to a typical organic solution system due to the relatively lower rate constant (kn) and the high viscosity and multicomponent properties of the melt system used in this study. This is the second contribution of this work. Keywords— Avrami model, Crystallisation, Fisher-Turnbull model, nucleation rate constant, Nyvlt model, palm oil fractionation.
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