Operability analysis of an exothermic semi-batch reactor

Operability characteristics for a semi-batch reactor with a single exothermic reaction are presented. We focus on how the desired reactor temperature profile determines the required jacket temperature and feed flowrate profiles. For example, a constant feed flowrate profile can be selected to meet jacket temperature constraints. We also show how the feed conditions and flowrate affect dynamic characteristics, including open-loop stability and nonminimun phase (''inverse response'' or ''wrong way'') behavior, which has a direct effect on the controllability of the process. The example system studied involves the production of a pharmaceutical intermediate with a large heat of reaction. Due to heat transfer limitations in large-scale manufacturing equipment, this reactor must be operated in semi-batch mode. We show how to select the operating strategy to ensure good operability when scaled-up to the manufacturing level.