Stability and Controllability of Batch Processes

Im proving the perform ance ofbatch processes requires tools that are tailored to the specificities of batch operations.These include a m athem atical representation thatexplicitly showsthe two independenttim e variables(the run tim e t and therun index k)aswellasthetwo typesofoutputs(therun-tim eand run-end outputs).Furtherm ore,corrective action can be taken via both on-line and run-to-run control.Thispaperinvestigatesthe im portantnotionsofstability and controllability forbatch processes,whereitisshown thata valueratherthan a yes-no answer needs to be considered.The tools required for evaluating these properties are readily adapted from the literature.Finally,the various control strategiesareillustrated via thesim ulation ofa sem i-batch reactor,and references arem ade to the appropriatetoolsforevaluating stability and controllability. K eywords:Batch Processes,Repetitive Processes,O n-lineControl,Run-to-run Control,Stability,Controllability.