Poison and life of catalyst

Unfortunately, all catalysts will deactivate under the same reaction conditions, but at different rates of deactivation. Catalyst designers need to continue to find ways that could render the catalyst being used most economically for a longer fife. Deactivation can be divided into two types reversible and irreversible. Both types of deactivation are not desirable. Even for the former case, the deactivated catalyst has to be taken out of the production line for reduction. 

Like living things, a catalyst goes through a life-death process, thus deactivation is inescapable. A good environment is needed to keep a catalyst active. Even in the worst environment, attempts are needed to overcome the adverse effects of the environment on the catalyst as far as possible. The catalyst will deteriorate and die without such efforts to maintain its activity. 

It can be seen that the key for correct use of a catalyst rests with knowing how to use the catalyst more efficiently and attaining a longer catalyst life. The first requirement is to investigate the reason why deactivation happens. 

There are seven reasons that would cause the loss of catalytic activity. Most of the time, two or more of these cases can happen at the same time, thus accelerating the deactivation process. 

22 Typical deactivation curve of ammonia synthesis catalysts  

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