Batchsize and topological criteria: a combined approach to safely optimize hazardous polymerization processes

Small and medium chemical enterprises are widely diffused in Italy. Particularly, they operate batch and semi-batch processes working on job orders and making a massive use of multipurpose reactors having an Emergency Relief System (ERS) already installed. A batchsize approach is a method focused on finding the reactor fill level that can lead to a single phase vapor flow whether an external fire occurs, so that the installed ERS can protect the reactor from overpressures. In this work, such an approach has been revised, by choosing a runaway reaction as design incidental scenario, and integrated with a suitable optimization procedure based on topological criteria. The new batchsize approach allows for computing a reactor fill level which is much more reasonable for industrial applications with respect to that one predicted by the older method, while the topological approach permits to identify the minimum dosing time capable of guaranteeing both reactor safety and high productivity. Theoretical results have been experimentally validated using data obtained by reaction calorimetry experiments, carried out in an isoperibolic RC1 equipment (1 L, Mettler Toledo), implementing the relevant case study of the solution homopolymerization of butyl acrylate.