Modeling of solid-particle effects on bubble breakage and coalescence in slurry bubble columns
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Experimental and Computational Multiphase Flow
Modeling of solid-particle effects on bubble breakage and coalescence in slurry bubble columns Adam Mühlbauer, Mark W. Hlawitschka (), Hans-Jörg Bart Lehrstuhl für Thermische Verfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 44, 67663 Kaiserslautern, Germany
Abstract
Keywords
Solid particles heavily affect the hydrodynamics in slurry bubble columns. The effects arise
breakup and coalescence
through varying breakup and coalescence behavior of the bubbles with the presence of solid particles where particles in the micrometer range lead to a promotion of coalescence in particular. To simulate the gas–liquid–solid flow in a slurry bubble column, the Eulerian multifluid
CFD simulation
approach can be employed to couple computational fluid dynamics (CFD) with the population balance equation (PBE) and thus to account for breakup and coalescence of bubbles.
solid-particle effect
In this work, three approaches are presented to modify the breakup and coalescence models
Article History
population balance equation slurry bubble column
to account for enhanced coalescence in the coupled CFD–PBE framework. The approaches are applied to a reference simulation case with available experimental data. In addition, the impacts
Received: 27 February 2020
of the modifications on the simulated bubble size distribution (BSD) and the applicability of the
Accepted: 14 May 2020
approaches are evaluated. The capabilities as well as the differences and limits of the approaches are demonstrated and explained.
Research Article
Revised: 4 May 2020
© The Author(s) 2020
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Introduction
A variety of chemical, petrochemical, biochemical, and metallurgical processes are carried out in slurry bubble columns on the industrial scale (Shah et al., 1982; Deckwer and Schumpe, 1985; Fan, 1989). Well-known examples can be found in the hydrogenation of carbon monoxide for the production processes of hydrocarbons (e.g., Fischer–Tropsch or methanol synthesis). The description of the complex hydrodynamics in gas–liquid-solid multiphase systems became of special research interest in recent years (Ojima et al., 2014; Sarhan et al., 2018). In particular, the determination of the BSD and the estimation of the volume-specific interfacial area are of major importance to model chemical processes with mass transfer. The solid-particle phase affects the hydrodynamics in the column drastically, and especially the effect on the total gas holdup in the apparatus has been stated repeatedly (Krishna et al., 1997; Luo et al., 1999; Li and Prakash, 2000; Vandu and Krishna, 2004). Empirical correlations for the gas holdup can be found collated in the work of Behkish et al. (2006). Depending on the particle size, adverse effects of [email protected]
the solid-particle phase occur. Particles with diameters in the sub-millimeter range (i.e., microparticles) lead to a decrease, whereas larger particles may increase the gas holdup (Sarhan et al., 2018). Microparticles chan
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