Modeling and Model Predictive Control of Composition and Conversion in an ETBE Reactive Distillation Column

Reactive distillation is a novel technology that has been successfully used in the production of ether fuel additives. This process integrates reaction and separation in a single unit-operation. The interaction of reaction and separation makes the process exhibit complex behavior such as process gain nonlinearity, significant interactions, process gain bidirectionality (i.e., process gain sign change), and steady-state multiplicity. These complex dynamics make process control of the reactive distillation column very difficult. In this work, the nonlinearity of an ETBE reactive distillation column was investigated, and a 2 × 2 unconstrained model predictive control scheme was developed for the product purity and reactant conversion control. The process dynamics were approximated by a first-order plus dead time model to estimate the process model for the model predictive controller. The model predictive controller was able to handle the process interactions well and was found to be very efficient for distur...