Numerical Investigation on the Effect of Pressure on Fluidization in a 3D Fluidized Bed

Verma, Vikrant; Padding, JT Johan; Deen, NG Niels; Kuipers, J.A.M.

doi:10.1021/ie502474k

Cited by 22 publications

(3 citation statements)

References 28 publications

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“…Traditionally, for CFD-based modelling of large-scale gas-phase polymerization reactors, full Eulerian (twofluid or multi-fluid) models based on the Kinetic Theory of Granular Flows have been used to study (all assuming uniform particle size): gas bubbles' behaviour and solids mixing, [136] pressure effects, [137] bed size effects, [138] and heat production in the solid phase. [139] In addition, mixing and segregation of particles [140][141][142] have been studied using multi-fluid models allowing the incorporation of multiple solid phases.…”

Section: Reactor Fluid Dynamicsmentioning

confidence: 99%

A conceptual multilevel approach to polyolefin reaction engineering

Soares

McKenna

2022

Can J Chem Eng

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This article gives a wide overview of different types of mathematical models that can be used to describe the polymerization of linear olefins with coordination catalysts. We expanded the conventional classification of mathematical models into micro-, meso-, and macroscale, to include seven modelling levels: catalysis, polymerization kinetics, thermodynamic equilibrium, particle transport phenomena, particle interactions, reactor fluid dynamics, and reactor residence time distribution. Some of these levels may coexist at the same scale, but they are better treated separately because they make use of distinct modelling approaches. How complex the models in each level need to be, as well as how many modelling levels should be implicitly included, depends on the type of application intended for the simulations. In this paper, we will argue that the proposed levels of mathematical modelling not only bring to our attention the complexity behind the simulation of laboratory-and industrial-scale olefin polymerization reactors but are also useful conceptual tools to assist us to decide which levels to include and which ones to exclude when we develop simulation packages to describe olefin polymerization processes.

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Section: Reactor Fluid Dynamicsmentioning

confidence: 99%

A conceptual multilevel approach to polyolefin reaction engineering

Soares

McKenna

2022

Can J Chem Eng

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“…In the past few decades, many researchers have studied the hydrodynamics of fluidized-bed reactors (Zenit, Hunt & Brennen 1997;Di Felice 1999;Duru et al 2002;Derksen & Sundaresan 2007;Verma et al 2014Verma et al , 2015Yang et al 2017;Lu, Peters & Kuipers 2020;Shajahan & Breugem 2020). In general, fluidized beds are classified into two different categories as either aggregative or particulate (Geldart 1973).…”

Section: Introductionmentioning

confidence: 99%

Competing flow and collision effects in a monodispersed liquid–solid fluidized bed at a moderate Archimedes number

2021

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We study the effects of fluid–particle and particle–particle interactions in a three-dimensional monodispersed reactor with unstable fluidization. Simulations were conducted using the immersed boundary method for particle Reynolds numbers of 20–70 with an Archimedes number of 23 600. Two different flow regimes were identified as a function of the particle Reynolds number. For low particle Reynolds numbers ( $20 < Re_p < 40$ ), the porosity is relatively low and the particle dynamics are dominated by interparticle collisions that produce anisotropic particle velocity fluctuations. The relative importance of hydrodynamic effects increases with increasing particle Reynolds number, leading to a minimized anisotropy in the particle velocity fluctuations at an intermediate particle Reynolds number. For high particle Reynolds numbers ( $Re_p > 40$ ), the particle dynamics are dominated by hydrodynamic effects, leading to decreasing and more anisotropic particle velocity fluctuations. A sharp increase in the anisotropy occurs when the particle Reynolds number increases from 40 to 50, corresponding to a transition from a regime in which collision and hydrodynamic effects are equally important (regime 1) to a hydrodynamic-dominated regime (regime 2). The results imply an optimum particle Reynolds number of roughly 40 for the investigated Archimedes number of 23 600 at which mixing in the reactor is expected to peak, which is consistent with reactor studies showing peak performance at a similar particle Reynolds number and with a similar Archimedes number. Results also show that maximum effective collisions are attained at intermediate particle Reynolds number. Future work is required to relate optimum particle Reynolds number to Archimedes number.

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“…Brouwer et al [7] also measured experimentally, using X−ray tomography, that bubble size was significantly reduced at higher pressures for similar gas flows at ambient pressure. Verma et al [8] employed two−fluid model numerical simulations to analyse the effect of pressure on fluidization in a 3D fluidized bed. They also found a slight decrease of bubble diameter and a change in the solids circulation vortex when pressure was increased.…”

Section: Introductionmentioning

confidence: 99%