Wageningen University & Research: Electric technology to save energy in drying processes

Scientists of five Dutch universities join forces in the ELECTRIFIED project. There they use the power of electricity and electrical fields to develop breakthrough technologies for large energy savings in industrial drying processes. Current drying processes to make, for example, powdered milk or paper are based on air or steam and are energy-intensive.

Maarten Schutyser, project leader and scientist at the Laboratory of Food Process Engineering of Wageningen University & Research, is convinced that the power of electric forces can significantly accelerate water removal processes with much less energy. With the new term ELECfficiency, we refer to a next – much more energy efficient – generation of electrified processes.

We focus on the unique properties of electricity in fundamentally changing the water removal technologies, so that they become more energy efficient
Maarten Schutyser, Associate Professor at the Laboratory of Food Process Engineering
Drying is central to the manufacturing of a large number of products, such as paper, seasoning and plant-based proteins. “You can use renewable electricity as a one-to-one replacement to power these processes, but this does not improve energy efficiency”, Schutyser states. “That is why we focus on the unique properties of electricity in fundamentally changing the water removal technologies, so that they become more energy efficient.”

Collaboration
ELECTRIFIED is a collaborative NWO project between five universities: Eindhoven University of Technology, Delft University of Technology, University of Twente, University of Groningen and Wageningen University & Research, and eight companies: Avebe, ANDRITZ, Cosun, Corbion, DSM, MEAM, The Protein Brewery and VNP. The project is funded by the NWO Key Technologies programme. Within this programme, the NWO (the Dutch Research Council) has honoured several projects that accelerate sustainable societal transitions through innovations. The ELECTRIFIED project studies three different methods for drying processes.

Absorbing gels
“The first method is electrodialysis, that can for example recover proteins from the juice residue in the potato processing industry”, says Schutyser. “To this end, electro-responsive hydrogels are used. These gels absorb water, which they release when electrified. With a special membrane it concentrates the fruit water. This is a much milder process than the existing approaches and less likely to damage the product.”

Charged particles
For drying products that contain less water, such as pasta or paper, electro-osmosis is a viable method. The pores of pasta and paper contain water, but also charged particles, which form a charged layer near the pore surfaces. The latter will prompt the particles to move, if an external electrical field is put in place. The particles subsequently drag the water out of the product with them. “For water that cannot be efficiently removed mechanically, electro-osmosis enables a reduction in the use of heat”, Schutyser explains.

Flow of ions
“To make powders, the industry currently uses spray dryers. The fluid product is sprayed into a tower and dried into a powder using hot air”, Schutyser clarifies. ELECTRIFIED aims to accelerate drying processes with electrohydrodynamics. This method uses an airflow of ions generated by a strong electric field. Thus, the process requires significantly less hot air and, therefore, energy.

These principles have never before been studied on this scale
Maarten Schutyser, Associate Professor at the Laboratory of Food Process Engineering
New generation of efficient processes
“We are working on the development of scalable machinery, based on these electrically driven processes”, Schutyser continues. To this end, scientists collaborate with equipment suppliers and for example with the Wageningen Technical Development Studio, who can construct the new equipment. “These principles have never before been studied on this scale. With this consortium, we develop a new generation of highly efficient electricity driven drying processes that allows a more sustainable industry.”