Steady-state and stability analysis of a population balance based nonlinear ice cream crystallization model

The process of crystallization can be modelled by a population balance equation coupled with an energy balance equation. Such models are highly complex to study due to the infinite dimensional and nonlinear characteristics, especially when all the phenomena of nucleation, growth and breakage are considered. In the present paper, we have performed the stability analysis on a reduced order model obtained by the method of moments, which remains still highly complex. The considered model has been developed by the Cemagref and validated on experimental data. After computation, we get a scalar equation whose solutions correspond to the equilibrium points of the system. This equation is finally solved numerically for a concrete physical configuration of the crystallizer. We show that in most instances, there is only one steady state. The possibility of multiple steady-states is discussed

MODELLING OF WAX CRYSTALLIZATION IN SOLVENT DEW AXING SCRAPED SURF ACE EXCHANGERS AND CHILLERS

The wax removal process using scraped surface exchangers and chillers in a solvent dewaxing unit is the most common industrial technology for the production of lubricant oils. The proper thennal design and control of the dewaxing process in these chilling machines is essential for a high quality product. The quality of the desired product is based on the control of the cooling rate and the wax crystallization process. Therefore, an appropriate mathematical model is required to simulate the dewaxing process for such complex wax-oil-solvent mixtures. A successful mathematical model requires a good estimation of the waxy oil-solvent properties, heat transfer characteristics, and wax crystal formation processes. To the best knowledge of the researchers, such coupling model for real solvent dewmdng unit does not presented in the literatures so far. In the present work, a reliable estimation model which comprised experimental and theoretical tools was developed