Computational fluid dynamics simulation of gas–liquid–solid polyethylene fluidized bed reactors incorporating with a dynamic polymerization kinetic model

Abstract

A comprehensive polymerization kinetics model that includes site formation, chain initiation, chain propagation, chain transfer and chain deactivation elementary reactions was incorporated into the three‐fluid computational fluid dynamics (CFD) model to describe the polymer properties in the gas–liquid–solid three‐phase polyethylene fluidized bed reactor. The effect of operating conditions on polyethylene properties was firstly discussed. Furthermore, due to the importance and complexity of scaling up three‐phase reactors, the incorporated CFD model was then employed to investigate the scale‐up influence, which indicates that the difference of flow hydrodynamics in the reactor due to scale‐up effect will result in the difference of polymerization reaction rate.

Gas‐Phase Polyethylene Reactors—A Critical Review of Modeling Approaches

“…The authors subsequently employed such three‐phase model, along with the droplet vaporization model [ 159,160 ] and a comprehensive kinetic scheme, to evaluate the impact of the amount of isopentane on reactor behavior. Although the dynamic variation of the gas heat capacity due to droplet evaporation and the increased monomer solubility in the polymer were not accounted for, CFD simulation outcomes showed a decrease in bed mean temperature as a function of the inlet concentration of isopentane, as depicted in Figure 13 .…”

Optimization of a 3D-printed tubular reactor for free radical polymerization by CFD

“…The boundary condition for wall and outlet are mathematically identical for the species transport and are given by Eq. (12). The difference between outlet and wall is captured due to the fact that the outlet possesses convective flow, while the wall does not (see Eq.…”

“…Recent research aimed at overcoming the inherent loss of information that comes along with using the method of moments, trying to establish a full molar mass distribution through iterative surrogate model methods. Also fluidized bed reactors and suspension polymerizations have been modelled [11][12][13].…”

A fast modeling of chemical reactions in industrial‐scale olefin polymerization fluidized beds using recurrence CFD

“…Polyolefins (POs), including polyethylene (PE), polypropylene (PP), ethylene–propylene elastomer (EPR), and so forth, are found widely‐used in many modern human‐life applications due to their remarkable physical, chemical, and mechanical properties, their ability to be recyclable and its relatively low cost. They can commonly be produced by employing the gas‐phase fluidized bed reactors (FBR), which are recognized as economically appealing with favorable good mixing and excellent heat‐transfer characteristics 1‐5 . In those catalytic fluidized bed reactors, the gas formed by unreact monomer(s) of ethylene fluidizes the granular bed and reacts with the catalyst or prepolymerized particles to produce a polymer particle growth 6 from Geldart size groups A/C upon groups B/D 7 .…”

“…They can commonly be produced by employing the gas-phase fluidized bed reactors (FBR), which are recognized as economically appealing with favorable good mixing and excellent heat-transfer characteristics. [1][2][3][4][5] In those catalytic fluidized bed reactors, the gas formed by unreact monomer(s) of ethylene fluidizes the granular bed and reacts with the catalyst or prepolymerized particles to produce a polymer particle growth 6 from Geldart size groups A/C upon groups B/D. 7 At the end of operation, the full-size polymer particles are withdrawn from the bottom in a dry granular shape.…”