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Separation of fatty acids by extractive crystallization
Abstract
The main objectives of this work were to provide a technical basis for recovery of selected, high purity fatty acids using fractional crystallization and to provide a solvent selection technique for extractive crystallization. Extractive crystallization utilizes subtle differences in size and shape and it is very well suited for the separation of saturated fatty acids from unsaturated fatty acids. The selection of the solvent for extractive crystallization is a very crucial step. The use of several single and binary solvent systems was theoretically as well as experimentally investigated. Wilson's equation was used to describe solid-liquid equilibrium. Two solvent selection criteria were developed. The first was based on solvent power and the second one was based on the trends in infinite dilution activity coefficients. High melting point solvents (such as t-butanol) offer attractive properties for crystallization. The mixed crystal area of a fatty acid in a solvent refers to the temperature and composition region in which co-crystallization of the fatty acid and the solvent takes place. By using a high melting point solvent, the mixed crystal area with the solvent can be increased, and the crystallization can be carried out at a higher temperature. Finally, a heuristic based separation synthesis strategy is proposed for fatty acids. A methodology to analyze multicomponent separation by crystallization is developed and is validated. The key heuristics and main design variables are identified. These are further illustrated through the analysis of soybean and crambe oil separation.
Subject Area
Chemical engineering|Food science|Organic chemistry
Recommended Citation
Wale, Sanjay N, "Separation of fatty acids by extractive crystallization" (1995). ETD collection for University of Nebraska-Lincoln. AAI9615004.
https://digitalcommons.unl.edu/dissertations/AAI9615004