In a typical heater treater application, liquid flows through a downcomer to the base of the treater, serving as a free-water knockout section. If the treater is located downstream of a free-water knockout, the bottom section can be reduced in size. If the total well stream is to be treated solely through this heater treater, then this section should be sized for a 3 to 5 minutes retention time. This time allows for both the oil and the water to settle out and will minimize the amount of fuel gas needed to heat the liquid stream rising through the heating section. The end of the downcomer in the Tri-Point design is slightly below the oil water interface to "water wash" the oil being treated. This will assist in the coalescence of water droplets in the oil.
The oil and emulsion rises over the heater fire-tubes to a coalescing section where sufficient retention time is provided to allow the small water particles in the oil continuous phase to coalesce and settle to the bottom.
Treated oil flows out the oil outlet. Any gas, flashed from the oil due to heating, flows through the equalizing line to the gas space above. The oil level is maintained by pneumatic or lever operated dump valves. Oil water interface is controlled by an interface controller, or an adjustable external water leg.
Tri-Point offers both vertical and horizontal treaters.