Comparative study of the electrostatic charging tendency between synthetic ester and mineral oil

The growing demands for improved fire safety, source material sustainability, environment friendliness, and asset life extension have driven the research and development efforts of synthetic esters, less-flammable fluids. However the relatively limited number of work on these esters and their cost still limit their uses to specific applications. This contribution reports some investigations onto the Electrostatic Charging Tendency (ECT) of a commercially available ester fluid. Comparison is made with mineral oil, as this is a fluid we are familiar with. Fresh (unaged) and aged fluid samples were investigated in a spinning disk system under laboratory controlled conditions. Changes in static electrification were compared to some aging indexes (interfacial tension, turbidity, relative dissolved decay products). This contribution is not only intended to provide a fresh review in this domain of research, but also contains a substantial amount of new material with a view of closing some gaps in the present state of knowledge of oil streaming electrification. The obtained results show that static electrification currents are affected by fluid motion velocity, type of paper, moisture content and the aging byproducts. It was also found that the removal of dissolved oxygen by nitrogen blanketing contributed to the reduction in static electrification.