Cause of catalyst deactivation

The catalyst will lose its activity rapidly or slowly under the influence of various factors during use. The reasons for catalyst deactivation are complex. It can be classified into the following categories:

1. Permanent inactivation

The active component of the catalyst is deactivated by the action (poisoning) of some foreign ingredients, often permanently. Most of these foreign components are chemically reacted or ion exchanged with the active components of the catalyst, resulting in changes in the active components. For example, acidic catalysts are neutralized by alkalis, and noble metal catalysts are poisoned by sulfides or nitrides. Deactivation of catalyst poisoning often manifests itself as a rapid decrease in activity. Loss of active components due to wear or sublimation during use also leads to permanent inactivation, which is often difficult to restore simply

2. The active components are covered and gradually inactivated, which is non-permanent inactivation. For example, the carbon deposition generated in the reaction process covers the active components or blocks the pores of the catalyst, so that the reactants cannot be contacted with the active components. These coverings can be removed by certain methods, such as being deactivated by carbon deposition, and can be revived by burning charcoal for regeneration.

3. Wrong operation leads to deactivation of the catalyst, such as excessive reaction temperature, violent fluctuation of pressure leading to confusion or crushing of the catalyst bed, etc. Such deactivation cannot be recovered.