Spray drying is a processing technique commonly used in the food and pharmaceutical industry to produce powders. The benefit of spray drying is that it gives control over the produced particles' shape and allows for agglomeration, with which one can control bulk properties such as dispersibility and flowability. The downside is that spray drying setups tend to be inflexible in operation and are designed with a large error margin, which reduces the spray dryer's cost efficiency.

A more cost-efficient design of spray dryers is complex due to a lack of insight into the rapid evaporation process and the collisions between partially-dried droplets and particles in the spray dryer. This project explores the relation of the degree of drying to the collision outcome when a partially-dried droplet has a collision in the spray dryer. Two aspects are crucial to this aim. Firstly, understanding how the degree and rate of drying influence the droplet's properties, which is necessary due to the formation of sharp concentration gradients in partially-dried droplets. Secondly, one must understand which collision outcomes are experienced by colliding droplets and how they change with the degree of drying. By combining both of these aspects, it is possible to find relations for the properties of the droplet and the collision outcome, which, ideally, can be used for a priori prediction of collision outcome in spray dryers.

About me

I was born in Gelderland, the Netherlands. I have a background in food science with a BSc. and MSc. in Food Technology from Wageningen University & Research and a Sustainable Food Process Engineering specialization. For my theses and internship, for which I spent half a year in the USA at UC Davis, I delved deeper into topics such as droplet drying and digestion of protein-rich food. As I enjoyed the engineering focus, I applied for a Ph.D. position at the Delft University of Technology in the van Steijn group, where I now investigate the influence of drying on the collision outcome of partially-dried droplets in spray drying.

E.J.G. Sewalt MSc

PhD candidate