My question is related to indications of channeling or bypassing in a catalyst bed.
An indication of bypassing or channeling is the Radial Spread (T.peak - T.min) of the multi-point thermocouples provided at the outlet of the bed i.e. difference between peak temp and min temp.
However, it is measured as Radial Spread divided by the Temperature difference across the catalyst bed:
RS/dT = (Tpeak-Tmin) / (Tpeak-Tinlet)
Where Tinlet is the average inlet temperature to the catalyst bed and the value of the ratio RS/dT should be below 0.5. Any value greater than this indicates channeling in the catalyst bed.
How is RS/dT an indication of Channeling?
Why is its limit 0.5?