Plug Flow Reactor Calculator

Calculator inputs

Use one stacked page layout. The calculator fields switch to 3, 2, and 1 columns across screen sizes.

Reference rate constant, k_ref

Use units consistent with your chosen reaction order.

Reaction order, n

Inlet concentration, C_A0 (mol/L)

Volumetric flow rate, Q (L/s)

Reactor volume, V (L)

Target conversion (%)

Operating temperature (K)

Reference temperature (K)

Activation energy (kJ/mol)

Reactor diameter (m)

Optional. This estimates reactor length from volume.

Plotly graph

The graph tracks conversion and outlet concentration across the reactor volume.

Example data table

Sample case: first-order kinetics, k = 0.08 s^-1, C_A0 = 2.0 mol/L, and Q = 5.0 L/s.

Volume (L)	Residence Time (s)	Conversion (%)	Outlet Concentration (mol/L)
15.00	3.00	21.337	1.573256
30.00	6.00	38.122	1.237567
45.00	9.00	51.325	0.973505
60.00	12.00	61.711	0.765786

Formula used

Design equation

V = F_A0 ∫₀^X dX / (−r_A)

Rate model

−r_A = k C_Aⁿ, with C_A = C_A0(1 − X) for constant-density flow.

Integrated liquid-phase result

For n = 1:

X = 1 − exp(−kV / Q)

For n ≠ 1:

V = [Q / (k C_A0ⁿ⁻¹)] × [1 − (1 − X)¹⁻ⁿ] / (1 − n)

Temperature correction

k = k_ref exp[(E_a / R)(1/T_ref − 1/T)]

This calculator assumes a single irreversible reaction, constant density, no axial mixing, and user-supplied consistent units for the selected kinetic order.

How to use this calculator

Enter the reference rate constant and reaction order.
Provide inlet concentration, flow rate, and reactor volume.
Add operating temperature, reference temperature, and activation energy when temperature correction is needed.
Optionally enter a target conversion to estimate required reactor volume.
Optionally enter reactor diameter to estimate physical length.
Press Calculate Reactor Performance to display results above the form.
Review the graph, export the summary, and compare your case with the example table.
Keep volume and flow units compatible so residence time remains correct.

FAQs

1. What does this plug flow reactor calculator estimate?

It estimates conversion, outlet concentration, residence time, outlet molar flow, target reactor volume, and optional reactor length for a constant-density tubular reactor.

2. Which kinetics can I use here?

You can use zero-order, first-order, second-order, fractional-order, or any other real reaction order, as long as your rate constant units match that order.

3. Does the calculator handle temperature effects?

Yes. When you enter activation energy, operating temperature, and reference temperature, the page adjusts the rate constant with an Arrhenius relation before calculating performance.

4. What assumptions are built into the model?

The model assumes steady flow, no axial mixing, one irreversible reaction, constant density, and negligible pressure drop. Gas expansion and multiphase effects are not included.

5. Why is consistent unit selection important?

Residence time depends on volume divided by flow rate. The kinetic constant also changes units with reaction order, so mixed units can distort the final answer.

6. What does the graph show?

The graph shows how conversion rises and concentration falls as fluid moves through reactor volume. This makes performance trends easier to inspect.

7. When should I use the target conversion field?

Use it when you know the required conversion and want the reactor volume needed to achieve that target under the selected kinetic conditions.

8. Can I export my results?

Yes. The results panel includes CSV export for spreadsheet work and PDF export for reports, quick sharing, or design documentation.