Download Electrohydrodynamic atomization of fat milk.

Electrohydrodynamic atomization of fat milk. G.J. Luttikhof1, V.A. Ganesan2,3, S. Porada3, J.C.M. Marijnissen2,4 and L.L.F. Agostinho2 1
Centre of Expertise Water Technology, Leeuwarden, 8934CJ, The Netherlands 2Faculty of Applied Sciences, Delft University of Technology, Delft, 2628CJ, The Netherlands 3High Voltage Water bv, Badhoevedorp, 1171PK, The Netherlands 4Institute of Nuclear Science & Technology, University of Nairobi, Nairobi, Kenya Abstract Electrohydrodynamic atomization (EHDA) is the process in which a strong electric field is used to influence the break-­‐up of a liquid dispersed through a capillary nozzle. Using this technique it is possible to decrease the droplet size and to improve the size distribution . The EHDA process has several modes depending mostly, on the electric field and the flow rate through the nozzle e.g. the cone-­‐jet mode, the simple-­‐jet mode and the intermittent cone-­‐jet mode. In one of the most explored modes, the cone-­‐jet mode, the flow rate is in the range of mL/h and the electric field is in the range of few kV/cm. This mode is largely used because it can produce droplets much smaller than the nozzle diameter with a relative standard deviation (RSD) of around 0,20. Some recent papers also describe the simple-­‐jet mode with much higher flow rates (hundreds of mL/hr, Agostinho e.a. 2012). In the Dutch dairy industry 2 – 3 % of the total dairy products is powdered milk. The most used technique for the production of this item is spray drying. The process is highly depending on the droplet size because it dictates the evaporation level and consequently the quality of the powdered milk. The use of EHDA can improve the efficiency of such system because it can provide smaller droplets (higher area), it creates bigger droplet to droplet distance (better spray dispersion) with relatively low energy input. In our experiment we have used a nozzle to plate configuration to investigate the production of fat milk droplets with EHDA. Results have shown that with flow rate of 350-­‐600mL/h/nozzle (simple-­‐jet mode) with a potential of 7kV, for a nozzle to plate distance of 2 cm, droplet size is decreased around 20% when compared to a no electric field atomization (0kV). Additionally the RSD proves to be smaller. If considered that droplet size and size distribution are critical parameters of the evaporation process, it is expected that EHDA can be used as a tool to improve powder milk production processes efficiency. References: 1
Prunet-­‐Foch, M. C. (1990). Electrostatic spraying of liquids: Main functioning modes. Journal of electrostatics 2
Boland, S. T. (2014). Milk proteins. nieuw zeeland.