1. Context

The rate at which industrial catalysts, whether soluble or solid, lose their activity depends very much on the characteristics of the process: nature and purity of the reactant(s), operating conditions, catalyst and reactor chosen. Fluid Catalytic Cracking (FCC) catalysts, for example, can be deactivated in a matter of seconds, an essential refinery process for converting heavy feedstocks into gasoline. This very rapid deactivation is explained by the heaviness and complexity of the feedstocks processed (comprising numerous and varied reagents and various impurities) and the severity of the operating conditions. By contrast, in processes using one or two simple, pure reagents and operating under mild conditions, such as ammonia synthesis or the liquid-phase alkylation of benzene by ethylene, the catalyst can work for several years without being regenerated or replaced.

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