Novel Coalescer Technology in First-Stage Separator Enables Single-Stage Separation and Heavy-Oil Separation

Abstract

Summary Aibel (former ABB Offshore Systems) has for a long while carried out fundamental research on compact separation. A significant part of the development has been to incorporate robust electrostatic coalescers into three phase separators. The current technology enables single-stage separation and accelerates separation of oil and water. The most recent product developed to enable single-stage separation is the Low Water Content Coalescer (LOWACC). The LOWACC is an electrostatic coalescer element, enhancing and accelerating the separation in an oil/water/gas separator. It is designed to operate as a polishing element for removal of the remaining droplets of water and is designed to be located downstream the Vessel Internal Electrostatic Coalescer (VIEC), which is a bulk separation device. A prototype polishing element, together with the bulk separation device, has been tested on several different real crude oils ranging from API 17 to API 29. For the API 29 crude, the water in oil (WiO) content was successfully reduced below 0.5% without the use of chemicals. For the challenging API 17 oil, the oil in water (OiW) was reduced to below 2–5%. All the test results verified good separation even with tough separation conditions that created stable emulsions and small droplets. The produced water leaving the separator contained 2 to 200 ppm oil in water.