Numerical simulation on runaway reaction and inhibition of styrene thermal polymerization

In order to achieve online monitoring and shortstopping of runaway reactions during styrene thermal polymerization, a Computational Fluid Dynamics (CFD) method concerning thermokinetic equations was used to establish a three-dimensional model of a stirred reactor. The distribution, development and elimination of hotspots in the system were studied considering the inhibition effect of different cold diluent injection locations. The results show that viscosity increase reduces heat convection in locations away from the impeller,which leads to uneven temperature distribution in the reactor. Cooling diluents can effectively control hotspot formation and reduce runaway reaction rate when the diluent is added to the hotspot region. Meanwhile, the volume average temperature is the lowest when the diluent is added to the impeller region. By considering temperature distribution within the reactor and using the divergence criterion method,this research provides theoretical support for optimal placement of reactor sensors, and prevention and control of thermal runaway reactions.