Enter tower design inputs
The form stays in a single content column, while the input controls shift from three columns to two and one on smaller screens.
Example data table
These sample values show how a preliminary packed tower screen can be reviewed before pilot testing.
| Water Flow | Air Flow | Influent | Target | Henry Constant | HETP | Available Height | Stripping Factor | Required Height | Predicted Outlet |
|---|---|---|---|---|---|---|---|---|---|
| 15 m³/h | 15,000 m³/h | 35 mg/L | 2 mg/L | 3.00 | 0.70 m/stage | 9.0 m | 2.209 | 2.44 m | 0.00 mg/L |
Formula used
1. Air and water molar flow
Liquid molar flow: L = Qw × 1000 / 18.01528. Gas molar flow: G = P × Qa / (0.082057 × T).
2. Stripping factor
The screening stripping factor is S = H × G / L, where H is the dimensionless Henry constant. Higher values support stronger transfer to air.
3. Required theoretical stages
For a target ratio r = Cout / Cin, the Kremser screening form is N = ln[1 + (S - 1)/r] / ln(S) - 1. When S = 1, the limit becomes N = 1/r - 1.
4. Packing height and predicted outlet
Required packing height is Z = N × Safety Factor × HETP. For available stages, the estimated outlet ratio is r = (S - 1) / (SN+1 - 1).
How to use this calculator
- Enter water flow and available air flow for the tower.
- Provide influent and target effluent contaminant concentrations.
- Use a dimensionless Henry constant suited to operating conditions.
- Enter tower diameter, HETP, packing height, and a safety factor.
- Submit the form to review stripping factor, stage demand, and predicted outlet concentration.
- Export the calculated result table as CSV or PDF for design notes.
Design interpretation notes
An air stripping tower moves volatile contaminants from water into an air stream. This calculator focuses on screening-level mass transfer behavior using Henry-driven equilibrium and a Kremser stage estimate. It helps compare airflow, tower size, and available packing before detailed pilot work.
The most important outcome is the stripping factor. If it stays below the target threshold, added packing height alone may not deliver the desired outlet concentration. In that case, the usual corrective actions are higher airflow, temperature review, pressure review, or selecting another treatment train.
The available packing height check is useful during retrofit studies. A plant may already have a fixed tower shell, yet still need to understand if present packing can reach new discharge limits. The predicted outlet line shows what the existing tower may deliver under the chosen assumptions.
Use the minimum air flow result as a thermodynamic screening value, not a final blower specification. Real projects also require contaminant loading checks, off-gas handling, packing selection, pressure drop, and safety review for emissions and worker exposure.
FAQs
1. What does the stripping factor tell me?
It compares volatilization strength against water loading. Higher values generally mean easier removal and fewer theoretical stages for the same outlet target.
2. Why can a target become unreachable?
If the stripping factor is too low, even very tall packing may not push the outlet below a certain limit. More airflow or a more favorable Henry constant is needed.
3. What is HETP in this calculator?
HETP means height equivalent to a theoretical plate. It converts the stage estimate into a physical packing height for preliminary tower sizing.
4. Can I use this for any contaminant?
It is best for volatile contaminants that respond well to air stripping. Low-volatility compounds often need adsorption, oxidation, membranes, or another treatment method.
5. Why is Henry constant entered directly?
Many design references publish contaminant-specific Henry data. Entering it directly keeps the tool flexible for different chemicals, temperatures, and engineering assumptions.
6. Does this include fouling or pressure drop?
No. The calculator screens mass transfer performance only. Final design still needs hydraulic checks, pressure drop review, packing selection, and maintenance allowances.
7. Why does the predicted outlet sometimes look much lower than the target?
That means the current airflow and available height provide more transfer capacity than the selected target requires under the simplified assumptions.
8. Should I trust the minimum air flow as a final blower size?
Use it only as an initial benchmark. Final blower sizing also depends on pressure losses, operating flexibility, startup margins, and off-gas treatment requirements.