Stabilization of continuous fluidized bed spray granulation with external product classification

This paper is concerned with stabilizing open loop unstable fluidized bed spray granulation with external product classification by means of feedback control. Using the linearization of the discretized population balance model of the process a transfer function is derived and reduced by its normalized coprime factor representation. For the simplified model a PI controller is developed and validated by simulating with the nonlinear plant model using an appropriate start-up strategy. As this controller does not achieve stability over the full range of operating conditions a robust control law is designed by H∞H∞ loop shaping.

► Stabilization of continuous fluidized bed spray granulation by means of feedback control is studied.
► A linear controller design model is derived by model reduction.
► Robust control is used to stabilize the plant over a wide range of operation conditions.