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If exothermic reaction temperature exceed beyond 30 degree C at the outlet of hydro-treating reactor bed then what will be the consequence? Whether the result of that coking or sintering of catalyst might take place for Co-Mo Catalyst? If feed cut and temperature rise above 300 degree C then what will happen to catalyst?

Additional:
If exothermic reaction temperature exceed beyond 30 degree C at the outlet of hydro-treating reactor bed (Normally maintain at 280 C) then what will be the consequence? Whether the result of that coking or sintering of catalyst might take place for Co-Mo Catalyst? If feed cut and temperature rise above 300 degree C then what will happen to catalyst? FYI, when NHT was restarted with HN feed, pressure drop was increased from 0.67 to 0.79. So what could be the cause of this pressure drop?
Ravinder Chib said nothing will happen to catalyst but is there any chance of coking as feed suddenly cut for 30 minutes long and temperature of reactor bed was increased for 30 minutes?
 
Answers
11/10/2017 A: Steve Mayo, Eurecat, smayo@eurecat.com
Coking in a hydrotreater requires conditions which favor dehydrogenation over hydrogenation -- high temperatures (in excess of 350C) combined with low hydrogen partial pressure. Hydrogen deficient components in the feedstock, especially (di)olefins, multi-ring aromatics and other coke-precursors are also more likely to lead to coke formation. The conditions described in the question are very unlikely to result in heavy coke formation.
There are many possible causes of increased pressure drop after restart, but coking is an unlikely cause in a NHT. Top bed fouling is far more likely from the introduction of particulates, iron or trash following the upset. If the feedstock contains olefins, gum formation at the top of the catalyst bed is another potential cause of pressure drop.
09/10/2017 A: ravinder chib, ***, rschib@rediff.com
Nothing happens to catalyst. Better look out temp vs steel tensile strength graph. If you passed mechanics in your engineering degree.