Development of compartment model for inhibition of thermal runaway in free-radical polymerization

Abstract

Shortstopping reactions via injection of chemical inhibitors is a promising technique of emergency response to prevent thermal runaway, with unique advantages of cost effectiveness and process sustainability over current evacuation practices. However, computational modeling of the inhibition process for ensuring successful designs remains challenging. In this paper, a compartment model is developed to investigate the design of the inhibition system with detailed characterization in both complex kinetic mechanism and nonideal mixing effect. The reactor volume is divided into a network-of-zones (NoZ), with each zone modeled as a well-mixed reactor. The free-radical solution polymerization of methyl methacrylate (MMA) in a stirred batch reactor is used as a demonstrative example. The flow parameters and network structure of compartment models are validated with the CFD simulation. The developed compartment models are employed to investigate interactions of poor mixing and exothermic chemistry that lead to thermal runaway and key design factors including injection location, quantity, kinetic requirement, and timing on the effectiveness of quenching thermal runaway.