Two-Phase Separator Sizing Calculator

Sizing Basis: This calculator uses the Souders–Brown equation (K-factor) and heuristics from Svrcek & Monnery style guidelines for sizing vertical and horizontal two-phase separators. It is intended as a preliminary design / check tool and does not replace detailed mechanical design to ASME/API codes.

Process Conditions

Separator Configuration

Holdup & Surge Time Basis

Actions

Vertical Separator Sizing Results

Key Design Parameters

Vapor Flow (Qv): -
Liquid Flow (Ql): -
K-Factor: -
Terminal Velocity (Ut): -
Allowable Vapor Velocity (Uv): -

Liquid Holdup & Surge

Holdup Time: -
Holdup Volume (Vh): -
Surge Time: -
Surge Volume (Vs): -

Calculated Dimensions

Required Diameter (Dv): -
Total Height (Ht, T-T): -
Resulting L/D Ratio: -

Height Breakdown (ft)

H_LLL: -
H_Holdup: -
H_Surge: -
H_Inlet: -
H_Disengage: -
H_MistElim: -

Design Basis & Heuristics Used

    Technical Notes

    Variable Definitions

    • Wv: vapor mass flow (lb/hr).
    • Wl: liquid mass flow (lb/hr).
    • ρv, ρl: vapor and liquid density at operating conditions (lb/ftΒ³).
    • Qv: vapor volumetric flow (ftΒ³/s) = Wv / (3600·ρv).
    • Ql: liquid volumetric flow (ftΒ³/min) = Wl / (60·ρl).
    • K: Souders–Brown K-factor (ft/s·√(lb/ftΒ³)), selected by pressure and mist eliminator presence (heuristic).
    • Ut: terminal (allowable) droplet settling velocity, Ut = K·√((ρlβˆ’Οv)/ρv).
    • Uv: design vapor velocity (ft/s). Vertical uses a margin (e.g., 0.75Β·Ut).
    • th, ts: holdup and surge times (min).
    • Vh, Vs: holdup and surge volumes (ftΒ³) = tΒ·Ql.
    • D, L: vessel diameter and length between tangents (ft).

    Formulas / Logic

    • Souders–Brown vapor capacity: Ut = K·√((ρlβˆ’Οv)/ρv).
    • Vertical sizing (screening): compute Qv, choose Uv, then area A = Qv/Uv and D = √(4A/Ο€), rounded to practical increments.
    • Holdup/surge: Vh=thΒ·Ql, Vs=tsΒ·Ql.
    • Vertical height build-up: total height (T–T) is the sum of heuristic bands for LLL, holdup, surge, inlet clearance, disengagement, and mist eliminator allowance.
    • Horizontal sizing (screening/optimization): searches D and L to satisfy (i) required liquid cross-sectional area for Vh+Vs and (ii) gas disengagement constraint based on Ut and horizontal gas velocity, within L/D limits.
    • Area fraction: horizontal liquid area uses circular-segment area fraction vs h/D (existing approximation retained for continuity).
    This is a preliminary sizing/check tool. Final dimensions must consider internals, nozzle arrangement, foam, slugging, controllability, and vendor guarantees.

    Assumptions / Notes

    • K-factor values are heuristic and depend on service, droplet size, internals, foaming tendency, and inlet device performance.
    • Valid only when ρl > ρv. If not, separation is non-physical.
    • Holdup/surge times are typical guidelines; apply your project/company design basis.
    • Horizontal β€œminimum weight” is a screening approximation; mechanical weight depends on actual thickness, corrosion allowance, material, and code requirements.
    • Pressure input is used for K-factor banding only; it does not calculate densities. Always use correct densities at operating conditions.

    Standards / References

    • API 12J (Oil & Gas Separators) and common separator sizing practices.
    • GPSA Engineering Data Book β€” separator sizing and Souders–Brown K-factor guidance.
    • Svrcek & Monnery style heuristics for preliminary separator sizing (holdup times, proportions).
    • ASME BPVC Section VIII for mechanical design (not covered by this calculator).
    πŸͺ We use cookies to improve your experience. Learn more