MODELING AND OPTIMIZATION OF AN INDUSTRIAL BATCH PROCESS FOR THE PRODUCTION OF DIOCTYL PHTHALATE

Dioctyl phthalate (DOP) is used in substantial quantities in industry, primarily as a plasticiser for PVC and other polymers. One route to i ts production is via the esterification of 2-ethylhexanol (2EH) with p hthalic anhydride (PA) using a homogeneous catalyst. The process can b e carried out in batch reactors. A detailed dynamic model describing b oth the physics and chemistry of the plant, and its operating procedur es has been constructed using the gPROMS process modelling system. It is shown that, by incorporating a sufficient degree of detail and elim inating unnecessary assumptions, the model is able to predict accurate ly the observed dynamic behaviour of an existing industrial plant. Fol lowing validation, the model has been used to derive optimal operating policies for the plant. This corresponds to a dynamic optimisation pr oblem incorporating an economic objective function, several time-depen dent decision variables (''controls''), the equipment design character istics and other time-invariant parameters, and all important constrai nts. This is then solved using the dynamic optimisation facilities in gPROMS.