High-Performance Electrostatic Coalescer – A Novel Technology for Improving the Economics of Oil-Water Separation

Abstract Crude oil dehydration is one of the first, most important and challenging steps in oil production and processing. To achieve rapid and energy-optimized demulsification of water-in-oil emulsions, Saudi Aramco and TechnipFMC have jointly developed a high performance electrostatic coalescence technology. This paper discusses the performance test results of this technology. Physical separation of emulsified water from produced crude oil is challenging due to the small water droplets, presence of surfactants covering the water droplets that inhibit the otherwise natural coalescence process, as well as the high viscosity of the continuous phase and the narrow density difference between oil and water in the mixture. Conventional mechanical and thermal methods are proven for viscosity reduction and efficient separation, but they also require high capital expenditure and large footprint. Deploying conventional electrostatic coalescers for demulsification proves to be uneconomic at remote locations. Chemical methods, namely the injection of chemical demulsifiers to dissolve the above mentioned surfactants, is expensive and makes the production process highly dependent on the supply of such chemicals, which can be affected by geo-economical as well as environmental circumstances. In this paper the performance results from tests conducted jointly between TechnipFMC and Saudi Aramco using the compact high performance electrostatic coalescer (HPEC) technology are presented. The HPEC was tested successfully on an Arab Medium crude oil under different process conditions, including different temperatures, electric field strengths, and two geometrical configurations of the electrostatic cell internal features. The study results demonstrate the rapidity and effectiveness of the HPEC in destabilizing Arab Medium crude oil emulsions.