Theory 118/Catalyst cycle/Onset phase
Deactivation Starts on a Coke Threshold
The claim
Catalyst deactivation begins when the ratio of coke deposition to burn-off exceeds one, so a low-severity operation never fouls.
01Mechanism
Active sites are covered by carbon; the ratio sets coverage.
02Prediction
Deactivation should track the ratio.
03Refutation
Deactivation tracking run time would remove deposition.