How the technology works
Within the NATCO DUAL FREQUENCY treater, bulk water and larger water drops are coalesced and separated by gravity in the weaker AC field that exists between the grounded water phase and the electrodes. The stronger DC field between the electrodes causes rapid movement of the remaining small water droplets through electrophoretic attraction, causing them to collide, coalesce, grow, and separate by gravity. The modulated voltage waveform ensures coalescence without fragmenting (which would arrest water droplet growth), enabling droplets to descend to the bottom of the vessel via gravity. This electrostatic separation process has a higher flux per square foot, which reduces vessel size requirements, while the advanced power unit decreases electric power demand.
In desalter applications, washwater is injected through a proprietary injection quill upstream of the mixing valve in the inlet piping. Together with the electrophoretic movement of the water droplets, this provides a very high degree of mixing. Superior mixing and improved dehydration make the NATCO DUAL FREQUENCY treater much more effective than conventional AC desalters of similar size.
Use of a high base frequency for the electrostatic field provides stronger electrostatic forces even in high-conductivity crudes and crude blends. Low-frequency amplitude modulation of the field improves conditions for water droplet coalescence, further enhancing dehydration and desalting efficiency.
We also retrofit existing AC treaters to improve their capacity.