Catalyst sintering is a phenomenon that leads to agglomeration, a reduction in the surface to volume ratio of catalyst, upon exposure to very high temperatures. It results in the loss of active sites due to alteration of the catalyst’s structure, agglomeration of dispersed metal and corresponding loss of surface area.
As a result of sintering, catalyst support and active metal sites can be sintered upon exposure to high temperatures. High water partial pressures can increase the severity of sintering. It can result in loss of active surface, reduction in catalyst activity, and degradation of catalyst performance. In most cases, it can result in permanent activity loss of catalyst.
High temperature situations might arise during regeneration and in temperature away or temperature excursion.
To avoid, this develop and strictly follow the procedures to control the uncontrolled temperature rise.
More about how to avoid from high temperature problems “Troubleshooting of Hydrotreating Reactor”