The NATCO DUAL FREQUENCY electrostatic treater uses both AC and DC power to provide significant process improvement, often more than 100%, over conventional AC electrostatic technologies. It uses our proprietary load-responsive controller—the NATCO LRC-II smart interface—and a three-phase high-frequency power unit to generate a customized electrostatic field that can be optimized for any crude oil.
The treater can be delivered as a heater treater, providing heating and dehydration in a single vessel and eliminating the need for an externally heated heat transfer fluid. It can also be provided as a degassing treater, eliminating the need for a separate degasser.
The NATCO DUAL FREQUENCY treater reduces capex and opex through its higher treatment capacity, higher tolerance to wet crudes, and increased dehydration performance. Moreover, it allows reduced demulsifier dosage, less washwater usage, and a lower operating temperature.
The LRC-II interface improves emulsion resolution via voltage modulation, enabling operation at the optimal voltage for multiple crude feedstocks, while managing upsets more rapidly and effectively. Parameter setup in the treater power unit can be updated from the LRC-II interface in real time while the unit is operating.
The HiFlo spreader improves vessel hydraulics and enhances performance to support higher process capacity.
The NATCO DUAL FREQUENCY treater uses the extremely efficient HiFlo spreader to evenly distribute the incoming wet crude and create a uniform vertical flow upward through the treater. This method eliminates grid bypass and local recirculation areas.
The 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 the water droplets to collide, coalesce, grow, and separate by gravity.
In desalter applications, washwater is added upstream of the mixing valve in the treater's inlet piping. Together with the electrophoretic movement of the water droplets, this provides a very high degree of mixing with the brine. 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. 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 and enable lower operating temperatures and emulsifier dosages.