6.10 Recovery of valuable, heat sensitive products and concentrates by Eutectic Freeze Crystallization

Eutectic Freeze Crystallization (EFC) is a newly developed crystallization process that operates at subzero temperatures. At the eutectic point both the solvent and the solute crystallize from solution. Density differences cause pure ice to float to the top and the solute to sink to the bottom, making separation by gravity possible. Because the process operates at low temperature there is no thermal degradation of heat sensitive compounds. The aim of this research is to develop the EFC technology for products and concentrates from temperature sensitive streams in the agro and food industry. As an example, the recovery of lactose from delactosed whey permeate (DLP) is chosen.

Research aim
The phase and crystallization behaviour of pure lactose solutions in water will be studied. Parameters of interest are the crystal growth rate of ice and lactose as function of temperature; the quality of the ice and lactose crystals with respect to size, shape and purity; the impact of impurities like citric acid and calcium phosphate on the crystallization process. Following this initial stage the process can be scaled up to a semi-continuous process at 10 litre reactor size scale. At this scale also typical parameters for a semi-continuous process like residence time will be studied. An energy and mass balance and a conceptual process design of the process will have to be made to assess the economic relevance. The obtained knowledge will be used directly by the industry partners involved in the research and close collaboration with the partners is encouraged.

The project entails aspects from chemical engineering (understanding of the EFC process) and mechanical engineering (design, building and improving a lab-scale EFC reactor). The ideal candidate thus has a solid knowledge of the physics and thermodynamics of the EFC process as well as practical issues involved in the lab-scale EFC experiments. You will be working in a multidisciplinary environment , so a good team spirit is regarded valuable.

The research project is part of the Wetsus research theme Dehydration, where Avebe (, Feyecon ( and EFC Separations ( are involved as company members.

Promotor: Albert van der Padt, Wageningen University

For more information contact Dr. Jaap van Spronsen, TU Eindhoven/EFC Separations ( or Doekle Yntema, Wetsus (

Wetsus, Leeuwarden, The Netherlands 


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