🗼 Multicomponent Distillation (FUG)

Shortcut sizing of multicomponent distillation columns using Fenske minimum stages, Underwood minimum reflux root-finding, Gilliland actual stages, and Kirkbride feed stage location.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

Mass Transfer

📊 Solver Telemetry ● ACTIVE

👁️ Views 16

⚡ Solves 16

💾 Downloads 395 📦 Fortran Code 6.4 KB

📅 Released Jun 2026

⏱️ Latency < 1 ms

🧪 Industrial Distillation Column Internal Reflux & Reboiler Simulation

Real-time visual simulation of vapor boilup, liquid reflux trays, feed injection & product split

📝 Configuration & Presets

🛢️ Benzene-Toluene (α=2.45) 🔥 Depropanizer LPG (α=2.10) 🍷 Bio-Ethanol Column ⚡ NGL Debutanizer (α=2.80)

📊 Key Components & Volatility

Relative Volatility α_LK/HK: Light Key wrt Heavy Key

Feed Flow Rate F [kmol/h]:

Feed LK Fraction z_F,LK [mol/mol]:

Feed HK Fraction z_F,HK [mol/mol]:

🎯 Product Purities & Reflux Factor

Distillate LK Target x_D,LK [mol/mol]:

Bottoms LK Residual x_B,LK [mol/mol]:

Feed Thermal Condition (q): 1.0 = Saturated Liquid, 0.0 = Saturated Vapor

Operating Reflux Ratio Multiplier (R / R_min): Industrial optimum: 1.20 to 1.40

FUG Short-Cut Formulations:
• Fenske: N_min = ln[ (x_D,LK/x_D,HK) / (x_B,LK/x_B,HK) ] / ln α
• Underwood: Σ [ (α_i z_F,i) / (α_i − θ) ] = 1 − q
• Gilliland: Y = (N − N_min) / (N + 1) vs X = (R − R_min) / (R + 1)
• Kirkbride: log(N_rect / N_strip) = 0.206 log [ (z_HK/z_LK) (x_B,LK/x_D,HK)² (B/D) ]

📊 Column Sizing Results

📊 Output Summary
💾 Fortran Source

Required Theoretical Stages (N)

N = 19.6 stages (≈ 20 trays)

Optimal Feed Tray: Stage 11.1 from top (Kirkbride)

R_op = 3.14

Minimum Stages (N_min, Total Reflux) 9.22 Fenske Equation

Minimum Reflux Ratio (R_min) 2.513 Underwood θ = 1.538

Distillate Flow Rate (D) 86.90 kmol/h 34.8 % of feed

Bottoms Flow Rate (B) 163.10 kmol/h 65.2 % of feed

📈 Gilliland Trade-Off: Actual Stages N vs Operating Reflux R

📉 Distillate Product Flow (D) vs Feed LK Composition (zF)

=================================================================
 THERMOFLUIDCALC — MULTICOMPONENT DISTILLATION (FUG) REPORT
=================================================================
Case Title                 : Refinery LPG Depropanizer Column
Total Feed Flow Rate (F)   : 250.00 kmol/h
Relative Volatility alpha  : 2.100
Feed LK / HK Composition   : 0.350 / 0.650 mol/mol
Distillate / Bottoms LK    : 0.960 / 0.025 mol/mol
Feed Thermal State (q)     : 0.90
Reflux Multiplier R/Rmin   : 1.25
-----------------------------------------------------------------
MINIMUM STAGES (Nmin)      : 9.22 theoretical stages (Fenske)
Underwood Root (theta)     : 1.5381
MINIMUM REFLUX RATIO (Rmin): 2.513 (Underwood)
Operating Reflux Ratio (R) : 3.142
ACTUAL THEORETICAL STAGES  : 19.59 stages (Gilliland/Molokanov)
Optimal Feed Tray Location : Stage 11.1 from top (Kirkbride)
Distillate Product Flow (D): 86.90 kmol/h
Bottoms Residue Flow (B)   : 163.10 kmol/h
=================================================================

📘 Calculation Methodology & FUG Standards

Fenske-Underwood-Gilliland Sequence

The classic short-cut distillation method provides rapid, high-accuracy preliminary column sizing prior to rigorous tray-by-tray equilibrium simulation.

Reflux Optimization Trade-Off

As operating reflux $R$ approaches $R_{min}$, required stages $N \to \infty$. As $R \to \infty$, $N \to N_{min}$ but reboiler energy explodes. The economic optimum lies between $1.15 R_{min}$ and $1.40 R_{min}$.

Key Engineering Assumptions

Constant molar overflow (CMO) along rectifying and stripping sections.
Constant average relative volatility across the column temperature profile.
Kirkbride equation for optimum feed stage entry.

ThermoFluidCalc Engineering Report