What is the difference between thermal deactivation of catalysts and hydrothermal deactivation?

Thermal deactivation is mainly due to the sintering and melting of the catalyst, while hydrothermal deactivation is primarily caused by the action of water vapor at high temperatures, leading to the breakdown of the catalyst. During operation, it is necessary to avoid excessively high regeneration temperatures, reduce the amount of water vapor that enters the regenerator, and prevent the steam at the nozzles from damaging the catalyst; efforts should also be made to ensure that the steam contains as little water as possible.

Thermal deactivation refers to the decrease in catalyst activity caused by high temperatures, whereas hydrothermal deactivation refers to the decrease in catalyst activity that occurs in the presence of high temperatures and water vapor. At high temperatures, the low-melting-point metals in the catalyst can cause sintering of the catalyst, leading to a decrease in specific surface area and pore volume, and thus deactivating the catalyst ； If water vapor is present at the same time, it will also cause dealumination of the molecular sieve, thereby reducing the catalyst’s activity.

Thermal deactivation: refers to the decrease in catalyst activity caused by high temperatures; at such high temperatures, the low-melting-point metals present in the catalyst can lead to its sintering, resulting in a reduction in specific surface area and pore volume, and thus deactivating the catalyst； Hydrothermal deactivation: refers to the decrease in catalyst activity that occurs in the presence of high temperatures and water vapor; this is because the combined effect of high temperatures and water vapor leads to the loss of aluminum from the molecular sieve, thereby reducing the catalyst’s activity. The hydrothermal stability of a catalyst is determined under laboratory simulation conditions. Thermal collapse: It occurs when water (in liquid form) comes into contact with a high-temperature catalyst and vaporizes rapidly, causing the catalyst particles to break apart. As the physical structure of the catalyst is damaged, its activity drops significantly.

Thermal deactivation: refers to the decline in catalyst activity at high temperatures; the low-melting-point metals present in the catalyst can cause sintering of the catalyst, leading to a reduction in specific surface area and pore volume, and thus deactivating the catalyst； Hydrothermal deactivation: refers to the decrease in catalyst activity that occurs under the presence of high temperature and water vapor, as these conditions cause the removal of aluminum from the molecular sieve, thereby reducing the catalyst’s activity.

Thermal deactivation: refers to the decline in catalyst activity at high temperatures; the low-melting-point metals present in the catalyst can cause sintering of the catalyst, leading to a reduction in specific surface area and pore volume, and thus deactivating the catalyst； Hydrothermal deactivation: refers to the decrease in catalyst activity that occurs under the presence of high temperature and water vapor, as these conditions cause the removal of aluminum from the molecular sieve, thereby reducing the catalyst’s activity.