Thermal behavior of a semibatch reactor during upset conditions as a function of dosing and temperature controller type

In fine chemical industries, potentially runaway reactions are often carried out in semibatch reactors to better control the heat evolution. For such processes, an uncontrolled temperature increase can trigger secondary undesired reactions or, worse, decompositions of the reacting mixture with consequent reactor pressurization and, eventually, physical explosion. For this reason, during years, it has been tried to simulate how a runaway phenomenon evolves as a consequence of a number of upset operating conditions: e.g. dosing errors, cooling system failure or external fire. In this work, a dedicated software has been developed and used to simulate a dosing error occurring during an industrial synthesis. Particularly,it has been analyzed the effect of the different industrial temperature control modes (isoperibolic and isothermal) and their related controller parameters onto the time evolution of the main process variables. Theoretical simulations have shown that different scenarios can arise as a function of these control features.