Utilization of corona discharge for contactless emulsion formation

Commercially available methods of emulsion formation are mostly either high power consuming or they are not yielding much of product as the emulsions are made in batches. This study considers a contactless method of emulsification via corona discharge. Using a pin-to-plate electrode configuration, corona discharge forms by creating a non-uniform electric field. Applying the corona discharge to the humidity source causes the tiny water droplets get ionized and with their charges they get shot toward the ground electrode, submerged in the oil medium. Considering the different processing parameters, it is possible to tune the rate of emulsification and the size of the dispersed droplets. It is observed that using corona discharge, it is possible to achieve fairly uniform emulsions with the droplet size distributions in the range of 8 – 200 μm. The considered processing parameters were the input high voltage, the horizontal and vertical distances between the needle and the ground electrode, and the depth of the silicone oil. The best results were achieved for the voltage of 10 kV, horizontal distance of 20 mm, vertical distance of 15 mm, and oil thickness of 8 mm on silicone oil 100 cSt where the size of water droplets were measured to be 8 – 12 μm.