Gas processing · Distillation shortcut (FUG) · GPSA §16
Condensate Stabilizer — Fenske-Underwood-Gilliland
Distillation shortcut: minimum stages (Fenske), minimum reflux (rigorous multi-root Underwood), actual stages (Gilliland), feed stage (Kirkbride) and reboiler/condenser duties. Enter components with relative volatility α (referenced to the heavy key), and pick the light/heavy keys.
Feed Components
Name
z mol%
α
Keys & Specs
Duty Inputs
kmol/h
kJ/kmol
Engineering Basis
Fenske: Nmin = ln[(dLK/bLK)(bHK/dHK)]/ln(αLK).
Underwood: solve ALL common roots θ of Σαizi/(αi−θ)=1−q in the key span, then Vmin=Σαidi/(αi−θ) simultaneously (rigorous multi-root Underwood; handles distributing between-key components).
Gilliland (Molokanov) → N at R = factor × Rmin; Kirkbride feed stage.
Duties: Qc = (R+1)·D·λ; Qr ≈ Qc (near-neutral feed).