14-09-2017, 01:12 PM
The activity of the catalysts usually decreases with time. The life of any catalyst depends generally on the type of reactions and the reaction conditions. For example, catalysts for catalytic cracking lose much of their activity in a matter of seconds due to carbon deposition at the surface, while the promoted iron catalysts used in the synthesis of ammonia have a useful life of years. For any catalytic process, the life of the catalyst is an important economic factor. To regenerate or replace deactivated catalysts, the process needs to be shut down and therefore production is interrupted. The subsequent separation and regeneration of catalysts also involves time and cost. Therefore, the deactivation of catalysts significantly increases the cost of production. Therefore, any catalytic process will be economically viable only if regenerations are required infrequently and can be done at low cost.