Contactless Method for Electrocoalescence of Water in Oil

This paper discusses
an experimental approach to study the effects
of a contactless method on electrocoalescence of water-in-oil mixture/emulsion.
A positive corona discharge is utilized using a sharp conductive needle
without direct contact with the mixture/solution to avoid potential
corrosion of the electrode. This creates a nonuniform electric field,
which is further used for the coalescence of water droplets in the
range of micro to macro in oil. Two approaches are employed in this
study: qualitative analysis conducted by visually studying coalescence
patterns in videos captured with a high-speed camera and a quantitative
analysis based on calculations obtained from dynamic light scattering
measurements. From the behavior of the water droplets under the electric
field, it is observed that dipole–dipole interaction, migratory
coalescence/electrophoresis, and dielectrophoresis have major roles
in promoting the coalescence events. The effects of oil viscosity
and power consumption on the coalescence rate are also investigated,
suggesting an optimal oil–water separation process. The results
of this study pave a path for developing a safe, contactless, rapid,
and low-power-consuming separation process, potentially suitable for
an offsite application.