The use of distributed parameter model is becoming a common approach for simulating liquidsolid flow in loop polymerization reactors. However, there are still several issues with it. One of them is the absence of modeling of distributed pressure, as no thermodynamic state-equation is incorporated into the model. In this work, inner pressure of the reactor was associated with temperature using a thermodynamic state-equation for high-pressure liquid. The thermodynamic state-equation was solved together with a dynamically distributed reactor model based on the mass, energy, and momentum conservation as well as polymerization kinetics to predict the dynamic trajectories of component concentration, temperature, pressure, and bulk mass velocity in the reactor. Industrial steady-state data were used for model validation. The application of the model was demonstrated by simulating the effect of recycle ratio on the above distributed reactor parameters. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013