On-line model based control of a safety constrained batch reactor subject to recipe uncertainties

This contribution presents the on-line model based level control of a batch reactor with reaction rate uncertainties. The analyzed chemical batch process is catalyzed by a catalyst which decomposes in the reactor; therefore it is fed several times during the batch. Although the optimal reactor temperature profile, using a fixed catalyst dosing policy, is optimized off-line an on-line control solution is needed in order to accommodate the reaction rate and level disturbances which arise due to catalyst dosing uncertainty (feeding time, mass and purity). The chemical reaction produces a vapour phase by product which causes the level change of the reaction mixture. The on-line control method is based on the shrinking horizon optimal control methodology and it uses a reaction and hydrodynamic model. It is concluded that the on-line level control strategy delivers good level control results despite the disturbances and an output feedback controller is needed to control the level on a discretization interval.