Hydrodynamic and heat transfer modeling of polydisperse fluidized bed olefin polymerization reactors

Abstract

A computational fluid dynamics model was coupled with population balance model (CFD-PBM) to investigate hydrodynamic and heat transfer phenomena in an ethylene polymerization reactor. A gas-solid multiphase flow was developed based on the Eulerian-Eulerian approach. The polymer particle size distribution (PSD) is represented by four node using the quadrature method of moment (QMOM). The model was used to study segregation& mixing, pressure drop, bed height and that to compute particles temperature and hot spots in the gas phase reactor. Results of simulation were validated with real industrial ethylene polymerization plant data. Result showed that not much segregation was observed and the particle size diameter remains constant in the bed. However, the fine polymer particles tend to move toward the top of the reactor. The small particles were likely to have high temperature, due to the high activity, and thus hot spots observed in the top the bed.