Here, in Part 2 of this series, we consider fluidized beds and slurry reactors with a continuous catalyst make-up and purge rate. From the perspective of an economic evaluation, the make-up catalyst is treated as an ongoing variable cost, rather than an initial investment that pays back over time. The principles outlined here can also apply to homogeneous catalyst systems with a large system inventory and continuous make-up and purge.
Reactor performance in terms of conversion of raw materials or selectivity to desired products can deteriorate as the catalyst ages. Rather than periodic changes of the entire catalyst charge, continuous or frequent additions and removals are common. This make-up rate affects the age distribution of catalyst particles in the fluidized bed and thus the reactor performance.
This article will show how to optimize the catalyst make-up rate for maximum process profitability.