An Insight into the Temperature Field and Particle Flow Patterns in a Fluidized Bed Reactor for Nonpelletizing Polyethylene Process Using a 3D CFD-PBM Model

Abstract

This work aims at exploring the temperature and polyethylene (PE) particle flow patterns in a pilot-plant fluidized bed reactor via 3D CFD modeling approach. A Eulerian–Eulerian model involving ethylene polymerization kinetics is integrated with population balance model to investigate the issues for both traditional pelletizing PE process (TPPP) and nonpelletizing PE process (NPPP). The results show that the regions with large temperature gradients have been observed in top area. The revealed particle flow patterns in two cases are analyzed using four typical flow patterns (patterns a–d) reported in literature. PE particles are vigorously contacted and mixed along the lateral and vertical planes of the reactor in TPPP (patterns b–d). Solid dispersion is intensely enhanced in the bed vertical direction (pattern d), and the flow patterns show larger circular flow (pattern a) in the radial direction under NPPP due to the larger particle size and gas velocity.