Free Water Knockouts

ETI provides systems to process and remove oil from principally produced water streams. Treating elements include wave-baffles, enhanced coalescing devices, degassing, and settling time. ETI offers FWKOs for a variety of applications for three-phase operation in vertical and horizontal configurations, as well as with incorporation of splitter boxes for flow averaging crude oil to multiple treating vessels.


144″ X 50′-0″ Heated Free Water Knockout with stainless internals, 69,000 B/D water removal.


Reasons for FWKOs
During crude oil production, some oil wells begin to increase the water content in the produced fluids. As the stream concentration approaches 70% water, water becomes the continuous phase. The FWKO has retention times that exceed conventional gas/liquid separators and can process the larger volumes of water. The quantity of gas normally is reduced at this stage of production, and a higher quality of oil and water is required.

The Process
Gases, water, and oil can be processed through a FWKO to skim off the oil, clean up the water, and degas the fluids. After this stage of separation, the water is routed to final coalescers, hydro-cyclones, or flotation equipment, while the crude oil is delivered to heater treaters for further processing and the gas is recovered/used as fuel. The purpose of the FWKO is to generate a relatively low water-cut oil phase, a relatively clean water phase, and a clean gas phase. The design of FWKOs is generally 150 microns oil-in-water for gutless vessels to 60 microns oil-in-water for enhanced coalescing devices. The practical limit of enhanced settling devices is 50 microns oil-in-water (also referred to as a Skimmer vessel). Sizing is often referred to in terms of 50-100 BPD/ft2. For heavy oils, FWKOs are designed around the quality of the oil emulsion rather than water quality.


Options and Features

  • Enhanced Coalescing Devices
  • Internal Coating
  • Alloy Materials
  • Piping to Skid Edge
  • Factory Insulation
  • Firetubes
  • Vortex Tubes
  • Demisting Vane or Mesh Pad
  • Skid-Mounted Modules
  • Ladders and Platforms
  • Heating Elements