A dynamically distributed reactor model for identifying the flow fields in industrial loop propylene polymerization reactors

Abstract

The use of distributed parameter model is becoming a common approach for simulating liquid-solid 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.

Temperature Dependence of the Kinetic Parameters of the Titanium–Magnesium Catalyzed Propylene Polymerization

“…The same activation energy was used for the temperature dependence of all the kinetic coefficients of the model that is used for the analysis of the polyolefin production process using the Spheripol technology in [ 7 ]. In [ 6 ], for the temperature dependence of the kinetic coefficients , , , , a single activation energy E = 217,46 cal/mol (E/R ≈ 6245) was used, as well as in the articles [ 8 , 9 ]. Yang et al [ 6 ] concluded that the ideal mixing model (CSTR) could be used to describe the flow structure in a loop reactor of propylene polymerization at a recirculation coefficient above 50.…”

“…In [ 6 ], for the temperature dependence of the kinetic coefficients , , , , a single activation energy E = 217,46 cal/mol (E/R ≈ 6245) was used, as well as in the articles [ 8 , 9 ]. Yang et al [ 6 ] concluded that the ideal mixing model (CSTR) could be used to describe the flow structure in a loop reactor of propylene polymerization at a recirculation coefficient above 50. The reactor model presented in [ 10 ] includes kinetic coefficients with activation energies of = = 12,000, = 10,000, and = = 14,000 cal/mol.…”

“…The literature review has shown that the process rate is determined by the kinetics of propylene polymerization on the TMC during the PP synthesis, which ensures intensive mixing in the polymerization equipment and the efficient reaction of the heat removal [ 6 ]. Single-center kinetic models approximate the experimental values of the PP yield (Yp,e) and its number average molecular weight (Mn,e) properly, but the mass average molecular weight (Mw,e) and the polydispersity index (Kwn,e) cannot be approximated.…”

Hydrogen effect modeling on Ziegler-Natta catalyst and final product properties in propylene polymerization

“…In 2013, Luo et al modeled loop propylene polymerization reactors in bulk media. The model targeted on commercial reactor variables without paying attention to kinetics study and final product properties [21].…”