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Separator Sizing Calculator

Per API 12J with Souders-Brown Methodology

Gas-Liquid Separator Sizing Calculator
Size 2-phase and 3-phase production separators using Souders-Brown equation for gas capacity and retention time for liquid capacity per API 12J and GPSA. Includes pressure-corrected K-factors, Stokes law droplet settling, vessel thickness per ASME VIII, and nozzle sizing per API RP 14E.

Flow Rates & Conditions

Gas flow at standard conditions (60°F, 14.7 psia)
Oil/condensate flow rate
same
Produced water (same units as oil)
psig
°F

Fluid Properties

lb/ft³
At operating conditions
cP
At operating temperature
lb/ft³
At operating conditions
cP
At operating temperature
lb/ft³
Typically 62.4 lb/ft³
μm
100-200 microns typical

Design Parameters

Affects K-factor for gas capacity
-
3-5 typical for horizontal
min
API 12J: 1-3 min for oil
-
1.15-1.25 for flow variations
in
4-6" for mesh pads

Calculated Sizing Outputs

Vessel Dimensions:
Diameter (ID), Seam-to-Seam Length (L_ss), Effective Length (L_eff), L/D Ratio.
Gas Capacity:
Gas Velocity (Vg), Terminal Velocity (Vt), K-Factor, Souders-Brown Limit.
Liquid Capacity:
Retention Time, Liquid Level Height, Surge Volume, Slenderness Ratio.

Design Formulas

Souders-Brown Equation (API 12J):

Vmax = K × √[(ρL - ρG) / ρG]

Maximum allowable gas velocity for droplet separation

Stokes Law (Droplet Settling):

Vd = g × dp² × (ρL - ρG) / (18 × μG)

Liquid Retention Volume:

Vreq = QL × tr × Fs

Shell Thickness (ASME VIII UG-27):

t = P×R / (S×E - 0.6×P) + CA

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

Design Guidelines

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"...