Method for protecting coalescer elements of an electrostatic coalescer device against electrically induced erosion and/or partial discharges

A method for protecting coalescer elements of an electrostatic coalescer device against at least one of electrically induced erosion and partial discharges during operation of the electrostatic coalescer device, the method comprising:

• providing the electrostatic coalescer device comprising a vessel which contains at least two coalescer elements, each coalescer element comprising an electrode enclosed by an electrical insulation,
• feeding a first mixture of water and oil or a second mixture of gas, water and oil into the vessel,
• supplying AC voltage to the electrodes of the at least two coalescer elements, thereby separating the first mixture into a first oil phase and a first water phase or separating the second mixture into a gas phase, a second oil phase and a second water phase,
• time-resolved determining an electrical impedance of at least one of the electrodes of the at least two coalescer elements and determining whether the electrical impedance of the at least one of the electrodes has been changed within a predetermined time period by more than a predetermined threshold and, if so, quenching or reducing a voltage supplied to the at least one of the electrodes to at most 70% of the AC voltage supplied to the electrode at a time of determining a change of the electrical impedance of the at least one of the electrodes until at least one of:
• the change of the electrical impedance of the at least one of the electrodes lies within a first predetermined range and the electrical impedance of the at least one of the electrodes lies within a second predetermined range,
• wherein the length of the predetermined time period is at most 1 second, and
• wherein the predetermined threshold for the change of the electrical impedance in the predetermined time period is at least 0.25%.