Per API 12J with Souders-Brown Methodology
Learn settling velocity, retention time, L/D ratios, and design per API 12J standards
Souders-Brown Equation (API 12J):
Maximum allowable gas velocity for droplet separation
Stokes Law (Droplet Settling):
Liquid Retention Volume:
Shell Thickness (ASME VIII UG-27):
K-factor Selection:
K-factors vary by vessel orientation, mist eliminator type, and operating pressure. Values are automatically selected per GPSA and API 12J.
Typical Retention Times:
• Oil phase: 1-3 min (2-phase), 3-5 min (3-phase)
• Water phase: 3-5 min minimum
Separator Selection:
• Horizontal: High liquid rates, foam control, L/D = 3-5
• Vertical: High GOR (>10,000 scf/bbl), small footprint, L/D = 2-4
Mist Eliminator Selection:
• Wire Mesh: 10-100 μm removal, ΔP = 0.5-1 psi
• Vane Pack: 5-50 μm removal, ΔP = 1-2 psi, compact
• None: Design for 500+ μm droplet, conservative
Standard Diameters (API 12J):
12", 16", 20", 24", 30", 36", 42", 48", 60", 72", 84", 96"...
Oil gas separator sizing uses the Souders-Brown equation for diameter (based on droplet settling velocity) and retention time requirements for length. Per API 12J: diameter controls gas-liquid separation, length controls liquid residence time.
Separator sizing calculators determine vessel dimensions (diameter and length) for 2-phase and 3-phase oil-gas-water separators using API 12J standards, Souders-Brown methodology, and retention time analysis.
Per API 12J: oil gravities above 35°API need 1 minute; 20-30°API need 1-2 minutes; 10-20°API need 2-4 minutes. Three-phase oil-water separation typically requires 3-30 minutes depending on fluid properties.
Horizontal separators provide longer residence time for better liquid separation and handle higher liquid rates. Vertical separators require less plot space and handle higher gas-to-liquid ratios more efficiently.
Souders-Brown equation: Vg = K√[(ρL-ρG)/ρG], where Vg is gas velocity, K is design factor (0.1-0.35), ρL and ρG are liquid and gas densities. Diameter = √(4Q/(π×Vg)) where Q is gas flow rate.