In-silico vinyl chloride suspension polymerization: Kinetic modelling, thermal runaway prediction, and prevention

In the present study, a combined kinetic and heat transfer model was developed to study the kinetics and predict thermal runaway of vinyl chloride (VC) suspension polymerization. Reactor temperature, monomer conversion, mole of initiator, radical concentrations in the two phases (i.e., VC-rich phase and PVC-rich phase), and average molecular properties were mapped during non-isothermal processes. Meanwhile, the risk of thermal runaway was evaluated using S-Z (divergence) and H-J criteria. Simulation results show that a lower jacket temperature T-j and a larger heat transfer coefficient U are able to postpone or even avoid the risk of thermal runaway. Both of the criteria serve well for the prediction of thermal runaway during non-isothermal processes. To prevent the occurrence of thermal runaway to the greatest extent, model-based design of strategies for an isothermal polymerization process was done. Specifically, either jacket temperature T-j or heat transfer coefficient U can be fine-tuned to maintain a 50 & DEG;C isothermal process.