ost important characteristics of commercial-scale reactor that it can be scientifically mimicked in both lab and pilot scales. It scientifically relates to back-mixing (axial dispersion) and bypass effects.

Value of catalyst-bed length over particle diameter of catalyst (L/dp) is frequently used for determining plug-flow behavior. Main parameters influencing plug-flow behavior include:

1. Flow behavior
2. Order of the main reaction
3. Conversion and selectivity

From the above figure, lab-scale reactor frequently suffers with the actual L/dp value. Lab-scale tests usually carried out in laminar-flow regime causes high requirement of L/dp.

Recommendations

1. Appropriately select and design lab-scale reactor in order to allow reconfiguration
2. Use inert bed dilution to ensure minimum required L/dp (see in https://www.linkedin.com/pulse/how-properly-apply-bed-diluent-during-catalyst-testing-sungnoen/)
3. Minimizing the influence of reactor wall on flow pattern called bypass or wall effect.

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