Calculator Inputs
Use the form below to estimate ethanol recovery, cut volumes, stillage strength, stage count, approximate boiling points, and collection time.
Formula Used
1. Ethanol in feed
Ethanol in feed = Feed volume × Feed ABV fraction
2. Recoverable ethanol
Recoverable ethanol = Ethanol in feed × Recovery fraction
3. Distillate volume
Distillate volume = Recoverable ethanol ÷ Target distillate fraction
4. Cut volumes
Heads = Distillate × Heads fraction
Tails = Distillate × Tails fraction
Hearts = Distillate − Heads − Tails
5. Bottoms strength
Bottoms ABV = Ethanol remaining in bottoms ÷ Bottoms volume
6. Minimum stages
Fenske equation: Nmin = ln[(xD/(1−xD)) × ((1−xB)/xB)] ÷ ln(α)
7. Actual stages
Actual stages = Nmin ÷ Column efficiency fraction
8. Collection time
Collection time = Distillate volume ÷ Collection rate
How to Use This Calculator
- Enter the total feed volume loaded into the still.
- Enter the feed strength as % ABV.
- Set the target average distillate strength.
- Choose an expected recovery percentage for ethanol.
- Enter heads and tails percentages for your cut plan.
- Provide a relative volatility value and column efficiency estimate.
- Set reflux ratio, pressure, and expected collection rate.
- Press Calculate Distillation to view results, steps, graph, and exports.
Example Data Table
| Example Input or Output | Value | Unit |
|---|---|---|
| Feed volume | 25.00 | L |
| Feed strength | 12.00 | % ABV |
| Target distillate strength | 88.00 | % ABV |
| Ethanol recovery | 85.00 | % |
| Heads cut | 5.00 | % |
| Tails cut | 10.00 | % |
| Estimated distillate volume | 2.90 | L |
| Estimated hearts volume | 2.46 | L |
| Estimated bottoms volume | 22.10 | L |
FAQs
1. What does this calculator estimate?
It estimates recoverable ethanol, collected distillate volume, heads, hearts, tails, bottoms strength, approximate boiling points, theoretical stages, actual stages, and collection time for a batch ethanol distillation run.
2. Why must target strength exceed feed strength?
This page models enrichment by distillation. If the target strength is not higher than the feed, the separation goal does not represent concentration through the column.
3. What is relative volatility?
Relative volatility compares how easily ethanol vaporizes versus water. Higher values indicate easier separation and usually reduce the number of theoretical stages required.
4. Why is column efficiency needed?
Real trays and packing never perform perfectly. Efficiency converts the ideal stage count into a more practical estimate for actual hardware performance.
5. Are the boiling points exact?
No. They are planning estimates based on typical ethanol-water data and a simple pressure correction. Detailed phase-equilibrium work needs more rigorous models and validated lab data.
6. Why are cut percentages important?
Cut percentages split the collected distillate into heads, hearts, and tails. They help plan how much product may be discarded, kept, or redistilled.
7. Does reflux ratio change product purity?
Yes, higher reflux usually improves separation quality. This calculator reports internal reflux load, while the chosen target strength and stage calculations summarize the expected separation goal.
8. Can I use this for final process design?
Use it for screening, teaching, and early planning. Final design should include validated vapor-liquid equilibrium data, energy balances, equipment limits, and safety review.