Simulation of Molecular and Particle Properties of Polypropylene Produced in Multizone Circulating Reactors

Multizone circulating reactor (MZCR) technology is an emerging and advanced olefin polymerization process, which allows the production of intimate mixtures of polyolefins with widely varying properties. In this study, a multimodel coupling method is proposed to understand the characteristics of gas-phase propylene polymerization in a multizone circulating reactor. The developed model which couples the kinetic-based moment method, the chain length distribution model, and the steady-state population balance model can be used to simultaneously account for the molecular and particle properties of polypropylene within the whole MZCR. Three key operating variables linked to product properties involving gas barrier conditions, catalyst conditions, and gas velocities are examined. The simulation results demonstrate that a wide range of polymer properties can be obtained by varying the reactor operating conditions. The MZCR technology offers tremendous advantages in flexibly tuning the molecular and particle properties of products as compared to the conventional fluidized beds, loop reactors, and stirred bed reactors. In contrast to previous work, the current study presents a comprehensive modeling effort in terms of both the molecular and particle properties of polymers in the novel MZCR technology.

Automated summary

Multizone circulating reactor (MZCR) technology is an advanced olefin polymerization process that enables the production of polyolefins with varying properties. This study proposes a multimodel coupling method to understand the gas-phase propylene polymerization in a MZCR. The developed model considers the molecular and particle properties of polypropylene and examines key operating variables related to product properties. The simulation results show that the MZCR technology allows for a wide range of polymer properties.