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[Display omitted] • Multiphase flow simulation in Trickle-Bed Reactors (TBR) using the Volume-Of-Fluid approach (VOF) • Pressure drop, liquid saturation and wetting efficiency prediction are investigated. • Three different catalyst shape particle loadings: spheres, trilobes and quadrilobes are studied. • Satisfactory predictions of hydrodynamic parameters: two-phase pressure drop, liquid saturation and wetting efficiency. • New wetting efficiency correlation accounting for gas velocity and particle shape effects. The characterization of hydrodynamics in Trickle-Bed-Reactors is a complex task due to the opacity of the medium. In particular, the determination of pressure drop, liquid saturation , wetting of the catalyst surface and catalyst shape effect on these parameters is very important for optimal catalyst use and reactor operation. Measurements under industrial conditions are limited to indirect estimations, and direct measurement methods are limited to near-ambient conditions. In this context, the objective of the present article is to use Computational-Fluid-Dynamics to investigate pressure drop, liquid saturation and wetting efficiency in Trickle-Bed-Reactors and to improve existing correlations, with a special focus on the catalyst shape effect and wetting prediction. The Volume-Of-Fluid approach was used to simulate two-phase flow through particle loadings of spherical, trilobe and quadrilobe-shaped particles. The numerical model was validated against literature correlations in terms of pressure drop, liquid holdup and wetting efficiency. The CFD model was then employed to explore two effects that does not reach out a consensus in existing literature, i.e effects of particle shape and gas-phase velocity on wetting efficiency. As a result, it was shown that CFD provides good predictions of pressure drop and liquid saturation for different catalyst particle shapes, the achieved deviations between CFD results and correlation estimations are below 20%. A new wetting efficiency correlation is also proposed. This new correlation is able to predict wetting efficiency with a precision of 6.99% for a wide range of liquid velocities (from 0.2 to 0.8 cm/s) and gas velocities (from 5 to 20 cm/s) and three particle shapes. [ABSTRACT FROM AUTHOR]

• This work investigate mass transfer in a heterogeneous catalytic hydrogenation for gas–liquid-solid reactors, by using CFD. • CFD is used for predicting hydrodynamic and catalyst geometry effect on mass transfer for three different reactors geometry. • CFD-VOF model has been validated with analytical solutions and experimental data. • This work shows that the film model is applicable in pure diffusion regimes and the resistances-in-series model is not applicable when the mass transfer occurs without bulk. • Predictive model is proposed for mass transfer in a micro-structured reactor and vertical spherical beads string. This work investigates Gas-Liquid-Solid mass transfer coupled to heterogeneous catalytic reaction using Computational Fluid Dynamics (CFD). The numerical model is based on the Volume-of-Fluid (VOF) approach, coupled with a convection–diffusion equation for mass transfer resolution. First, the numerical method is validated on a falling liquid film over a semi-infinite planar surface. Then, a micro-structured reactor with α-methylstyrene hydrogenation is studied. A good agreement is found between experimental data of Tourvieille et al. (2013) and simulation results. Afterwards, a vertical spherical beads string is investigated. Convective transport by transversal velocities is identified as an important contributor to the overall Gas-Liquid-Solid mass transfer. While the film model is applicable in pure diffusion regimes, the resistances-in-series model is not relevant and over-estimates the real mass transfer by nearly 30% when mass transfer occurs in liquid film flow without bulk. The present work shows how CFD can be an effective tool for predicting hydrodynamic and catalyst geometry effect on mass transfer in Gas-Liquid-Solid reactors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Characterization of ceramic open cell foams via X-ray computed micro-tomography. • Foams materials: zirconia, silicon carbide and alumina of 30–45 ppi. • Lean combustion of methane (concentration 0.5 and 1 vol%) over PdO/Co 3 O 4 at 3 wt.% • Mass transfer coefficients measured under diffusional control conditions. • Dimensionless correlation Sh = A∙Rem∙Sc1/3 for a wide range of geometrical properties. In this work, we characterized ceramic open cell foams made of zirconia, silicon carbide and alumina of different nominal pore densities (30–45 ppi) using X-ray computed microtomography. This technique allowed the comprehensive and quantitative extraction of morphological and geometrical characteristics of the structures (pore size, strut diameter and length, node diameter, open porosity and specific geometrical surface area). An empirical model was proposed to determine the specific surface area from parameters easily accessible with standard laboratory equipment. Moreover, lean CH 4 combustion tests were performed on ceramic foams coated with PdO/Co 3 O 4 at 3 wt%. Mass transfer coefficients of the foams were measured by monitoring the oxidation reaction under diffusional control conditions. We derived a dimensionless correlation of the type Sh = A∙Rem∙Sc1/3. Finally, the pressure drop across the foams as a function of surface velocity was evaluated and compared with various experimental data and models available in the literature. [ABSTRACT FROM AUTHOR]