Calculator Inputs
Example Data Table
Illustrative examples for continuous reactor sizing. Replace these values with plant or laboratory data.
| Case | Reactors | Gross Volume per Reactor | Usable Factor | Void Fraction | Feed Rate | Estimated Space Time |
|---|---|---|---|---|---|---|
| Bench slurry loop | 1 | 12 L | 0.95 | Not applied | 4.5 L/min | 2.53 min |
| Packed-bed pilot | 2 | 0.75 m³ | 0.90 | 0.42 | 0.22 m³/h | 5.15 h |
| Neutralization train | 3 | 1.2 m³ | 0.88 | Not applied | 1.6 m³/h | 1.98 h |
| Fixed-bed polishing unit | 2 | 45 ft³ | 0.93 | 0.37 | 6.0 gpm | 2.92 h |
| Continuous esterification | 1 | 600 gal | 0.91 | Not applied | 3.2 gpm | 2.84 h |
Formula Used
The core calculation uses the reactor volume available to moving fluid at inlet conditions.
Where:
- τ = space time
- Veff = effective reactor volume after usable-factor and optional void-fraction adjustments
- Qin = inlet volumetric flow rate
In hourly form, the calculator reports:
For selected basis options, effective volume is:
Set fvoid = 1 when void volume is not part of your design basis.
How to Use This Calculator
- Select the calculation mode that matches your design task.
- Enter per-reactor volume and the number of identical reactors.
- Choose whether you want gross volume or packed-bed void volume.
- Apply a usable volume factor to account for internals, headspace, or non-active zones.
- Enter feed rate for analysis, or enter a target space time or space velocity for sizing tasks.
- Pick display units for time, volume, and flow so the output matches your report format.
- Submit the form to show the result above the calculator.
- Export the result card as CSV or PDF for documentation.
FAQs
1. What does space time mean in reactor work?
It is the time needed to process one reactor volume of feed at inlet conditions. It helps compare equipment size, throughput, and expected contacting time under steady operation.
2. Is space time the same as residence time?
Not always. For ideal steady systems with constant density, they can align closely. In nonideal flow, mixing, channeling, or density changes can make actual residence time distributions differ.
3. When should I use packed-bed void volume?
Use it when only interstitial fluid space is intended to represent the flowing volume. This is common in packed columns, catalytic beds, and adsorption units.
4. Why include a usable volume factor?
It lets you reduce nominal vessel volume for baffles, disengagement space, nonwetted regions, or conservative design margins. That creates a more realistic operating estimate.
5. What is space velocity?
Space velocity is the reciprocal of space time. Higher values mean faster throughput relative to available reactor volume, while lower values indicate longer contact time.
6. Can I use this for gases and liquids?
Yes, but use the inlet volumetric flow basis consistently. For compressible gas systems, verify whether standard or actual inlet conditions are required by your design method.
7. Why can two parallel reactors change total space time?
Adding identical parallel reactors increases total available volume. If the total feed stays fixed, overall space time rises because more reactor volume is available per unit flow.
8. Does this calculator predict conversion?
No. It estimates hydrodynamic sizing metrics only. Conversion also depends on kinetics, stoichiometry, temperature, pressure, catalyst behavior, and reactor model assumptions.