Harrison et al (2016) Image Analysis of Palm Oil - Journal of Crystal Growth.pdf (2.08 MB)

Image analysis of palm oil crystallisation as observed by hot stage microscopy

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journal contribution
posted on 14.06.2016, 11:06 by Peter D. Harrison, Kevin W. Smith, Krishnadath Bhaggan, Andy Stapley
An image processing algorithm previously used to analyse the crystallisation of a pure fat (tripalmitin) has been applied to the crystallisation of a multicomponent natural fat (palm oil). In contrast to tripalmitin, which produced circular crystals with a constant growth rate, palm oil produced speckled crystals caused by the inclusion of entrapped liquid, and growth rates gradually decreased with time. This can be explained by the depletion of crystallisable material in the liquid phase, whereas direct impingement of crystals (the basis of the Avrami equation) was less common. A theoretical analysis combining this depletion with assuming that the growth rate is proportional to the supersaturation of a crystallisable pseudo-component predicted a tanh function variation of radius with time. This was generally able to provide good fits to the growth curves. It was found that growth rate was a relatively mild function of temperature but also varied from crystal to crystal and even between different sides of the same crystal, which may be due to variations in composition within the liquid phase. Nucleation rates were confirmed to vary approximately exponentially with decreasing temperature, resulting in much greater numbers of crystals and a smaller final average crystal size at lower temperatures.



  • Aeronautical, Automotive, Chemical and Materials Engineering


  • Chemical Engineering

Published in

Journal of Crystal Growth




28 - 38


HARRISON, P. ... et al., 2016. Image analysis of palm oil crystallisation as observed by hot stage microscopy. Journal of Crystal Growth, 444, pp. 28-38.


© Elsevier


AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date



This paper was accepted for publication in the journal Journal of Crystal Growth and the definitive published version is available at http://dx.doi.org/10.1016/j.jcrysgro.2016.03.026.