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Calcimator

Distillation Column Calculator

Estimate minimum and actual theoretical stages, minimum reflux ratio, and feed stage location using the McCabe-Thiele simplified approach.

Inputs

mole fraction
mole fraction
mole fraction

Results

Minimum Stages (Fenske)

6.43 stages

Actual Theoretical Stages

10 stages

Minimum Reflux Ratio1.1
Feed Stage Location5 (from top)
How to Use This Calculator
  1. Enter the Feed Composition (z) as the light component mole fraction (e.g., 0.50 for 50 mol% light component in feed).
  2. Enter the Distillate Composition (xD) and Bottoms Composition (xB) as light component mole fractions defining the required separation.
  3. Enter the operating Reflux Ratio — typically 1.2–1.5× the minimum reflux ratio as a starting design point.
  4. Enter the Relative Volatility (α) — ratio of vapor pressures of the light to heavy key component at average column temperature.
  5. Read Minimum Stages (Fenske equation) and Actual Theoretical Stages needed at the chosen reflux ratio.
  6. Use the Feed Stage Location (from top) and Minimum Reflux Ratio as design targets for detailed column simulation or vendor specification.

How the result changes with Relative Volatility

Relative VolatilityMinimum Stages (Fenske)Actual Theoretical Stages
2.915.51 stages8 stages
7.662.89 stages4 stages
132.3 stages4 stages
182.04 stages4 stages

What each input means

Feed Composition
Mole fraction of the light key component in the feed stream.
Distillate Composition
Desired mole fraction of the light key in the distillate product.
Bottoms Composition
Desired mole fraction of the light key in the bottoms product.
Reflux Ratio
Ratio of liquid returned to the column to distillate withdrawn (L/D).
Relative Volatility
Ratio of vapor pressures of the light key to the heavy key component (α).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Feed Composition = 0.5, Distillate Composition = 0.95, Bottoms Composition = 0.05, Reflux Ratio = 2.5 = 5 input(s) provided
  2. Calculate Minimum Stages
    Minimum Stages
    6.43 = 6.43
  3. Calculate Actual Theoretical Stages
    Actual Theoretical Stages = max(actualStages
    10 = 10
  4. Calculate Minimum Reflux Ratio
    Minimum Reflux Ratio = Math
    1.1 = 1.1
  5. Calculate Feed Stage Location
    Feed Stage Location = max(feedStageLocation
    5 = 5

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