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Vessel Retention
Horizontal Vessel · NFC Services
Vessel Dimensions
Diameter
in
Length
ft
Cu Inches
Gallons
Barrels
Vessel
Flow Rates
Hourly Base
Input Rate
bbl/hr
Bbl/day bpd
Bbl/min bpm
Retention min
Time to Fill min
Daily Base
Input Rate
bbl/day
Bbl/hour bph
Bbl/min bpm
Retention min
Time to Fill min
* Retention time based on 60% operating fill level  ·  Time to Fill assumes vessel empty to full at constant rate
Gravity Separation Estimate
API Gravity of Oil
10° Heavy 30° Medium 55° Light
30
° API
Oil Spec. Gravity
Δ Density (kg/m³)
Fluid Height @ 60%
Water Column
Hourly Base
Retention
Sep. Needed
Daily Base
Retention
Sep. Needed

Separation time uses Stokes' Law — 200-micron average droplet, 100°F water viscosity (0.68 cP). Settling distance is the water column at 60% fill: bottom 90% of fluid depth. Hotter fluid separates faster. Colder fluid separates slower.

Assumes discrete droplets in a 50/50 oil-water mixture. Emulsified or chemically stabilized fluids will not separate gravitationally regardless of vessel size. Use with caution below 20° API — density contrast with water becomes minimal.

Ballpark estimates only. Not a substitute for engineering design or lab characterization.