Electrostatic coalescers enhance the performance of liquid/liquid separators by increasing the dispersed phase drop size. The increased droplet size results in an improved settling rate, allowing the dispersed phase to be separated in shorter time.
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Coalescers are normally equipped with an internal grid of high voltage electrodes suspended in water containing an oil layer to induce an electric field. This causes the water droplets to attach to one another and then to coalesce, to form larger droplets. These in turn promote their gravity settlement into water phase below the oil layer.
In addition to supplying conventional electrostatic coalescers Aker Solutions also supplies compact electrostatic coalescers (CEC™), which are ideal for high water cut and FPSO applications, as well as high performance coalescer plate packs for retrofit into existing vessels.
- Droplets become polarized and are attracted to each other
- In AC fields small droplets vibrate and move, causing collisions
- Emulsifying films are distorted and weaken
- Smaller water droplets coalesce into large droplets
- Promotes faster settling or separation of water from oil
- Coalescence rate is dependent on flow conditions (turbulence)
For each application, coalescing media is specially designed to take into account the nature of the process fluid, any contaminants, maintenance and special installation requirements.