Computational study of flow and heat transfer in fixed beds with cylindrical particles for low tube to particle diameter ratios

Zhang, Minhua; Dong, He; Geng, Zhongfeng

doi:10.1016/j.cherd.2018.01.006

Cited by 54 publications

(12 citation statements)

References 50 publications

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“…Moving toward the center, the ring distributions become more scattered, and the annular shape is less distinctive. A similar pattern of ring distribution was earlier observed in different columns 27,52 . The Pro‐Pak column is denser as compared to the Raschig ring column due to its semi‐cylindrical shape design.…”

Section: Resultssupporting

confidence: 81%

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The influence of random packed column parameters on the liquid holdup and interfacial area

Bao

Singh

et al. 2022

AIChE Journal

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Carbon dioxide capture via solvent absorption in packed columns has emerged as a potential technology to mitigate coal‐fired power plant CO2 emissions. Parameters, including packing types, solvent properties, and operating conditions, could potentially affect the packed column CO2 capture efficiency. To understand the importance of those parameters and help packed column optimization, a design of experiments (DoEs) method was proposed to generate input parameter matrix. Combined with multiphase computational fluid dynamics (CFD), the random packed column parameter influence on the liquid holdup and interfacial area can be efficiently investigated. Surrogate‐based sensitivity analysis shows that the solvent flow rate and contact angle are key factors dictating liquid holdup and interfacial area. On the other hand, solvent viscosity has a marginal impact on the interfacial area. The sensitivity scores were calculated for each input parameter to guide the selection of dimensionless numbers for the liquid holdup and interfacial area correlation development.

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Section: Resultssupporting

confidence: 81%

“…A similar pattern of ring distribution was earlier observed in different columns. 27,52 The Pro-Pak column is denser as compared to the Raschig ring column due to its semi-cylindrical shape design. With the hollow semi-cylindrical shape, the Pro-Pak ring can be aligned with the column wall as well as the inter-ring arrangement.…”

Section: Design Of Experimentsmentioning

confidence: 99%

The influence of random packed column parameters on the liquid holdup and interfacial area

Bao

Singh

et al. 2022

AIChE Journal

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“…[296,297] A good comparison of some methods with regard to packing generation was presented by Fernengel et al [298] for spheres, Caulkin et al [291] for cylinders, and Flaischlen and Wehinger, [299] who investigated packings of cylinders, hollow cylinders, and some more complex shapes. These numerical packing algorithms are frequently used to generate packings for subsequent fluid dynamics, [139,287,[300][301][302][303][304][305][306][307][308][309][310][311] heat, [288,296,[312][313][314][315][316][317][318][319][320] or mass transfer simulations. [321][322][323][324][325][326][327][328][329][330][331] The numerical procedures are well capable of geometric packing analysis, allowing separate material property variation, packing procedure evaluation, and shape factor analysis on a large scale and in a fast and cost-efficient manner.…”

Section: Source Shapementioning

confidence: 99%

Review on the structure of random packed‐beds

Seckendorff

Hinrichsen

2021

Can J Chem Eng

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Independent from their intended purpose, the understanding of structural characteristics of random packings of particles having defined shapes is important to understand and optimize fluid dynamic behaviour, heat, and mass transfer. The packing structure can be described by the coordination number, local porosity profiles, the average porosity, and pore characteristics, which are influenced by the wall and thickness effect; the material, shape, and size distribution of the packing particles; the packing and compaction mode; and the shape and material of the packing's containing walls. Therefore, existing knowledge on the structure of randomly packed mono-sized particles is reviewed to provide an updated selection of relevant parameters and their derived correlations obtained by experimental, numerical, and analytical means.packed-bed reactor, porosity, random particle packings, review, structure | INTRODUCTIONRandom packings of particles having defined shapes are deployed in all kinds of industrial applications and come in all orders of magnitude. The most prominent examples comprise micro-sized particle beds as commonly used in chromatography packed columns, [1][2][3] packed-bed reactors filled with catalytic shaped bodies having millimetre size, [4,5] packed columns used in separation processes such as distillation incorporating particles in the lower centimetre range, [6,7] and the pebble-bed reactor, which is a gas-cooled nuclear reactor, moderated by a packing of graphite spheres. [8][9][10] In addition to those, numerous less-known applications of packed-beds exist, ranging from powder-bed 3D printers, [11] solar-energy storage systems, [12] earth science, [13] civil engineering, [14,15] and pharmaceutical processing, [16] to the pyrolysis of pelletized wood fuels, [17] to name but a few.Irrespective of its intended purpose, the extent of a packed-bed is limited by a confining wall of commonly cylindrical shape, though flat plates and other container geometries are possible. Despite its generally random nature, close to this confinement the particles' placement is naturally forced to align with the wall's geometry. This imposed order reaches a couple of particle diameters into the packing and is usually named the wall effect. Its influence on the overall packed-bed characteristics decreases with increasing tube-to-particle diameter ratio λ = D d p . While most applications operate in an only sparsely affected λ-range, this effect becomes dominant, for instance, in catalytic multitubular reactors, typically performing at λ = 4-7 [18] or a single-pellet-string reactor with a λ < 2. [19] Moreover, some packed-bed utilizations, especially chromatography columns, have very delicate requirements regarding bed homogeneity and its derived characteristics.Abbreviations: DEM, discrete element method; Erfc, error function; J 0 , Bessel function of first kind and zero order; MRJ, maximally random jammed; RCP, random close packing; RLP, random loose packing.

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“…Wehinger et al combined particle packing structure with detailed reaction mechanisms of catalytic dry reforming of methane over rhodium and studied the interaction between chemical kinetics and transport of momentum, heat, and mass [25]. Zhang et al studied the flow and heat transfer in fixed beds considering the packing structures of cylindrical particles and low tube to particle diameter ratios [26].…”

Section: Dem Modelmentioning

confidence: 99%

“…Two parts of simulations were performed in this research. To verify the accuracy of the simulation framework, a simulation of a droplet falling on a sphere particle was carried out according to Du et al's research [26], and the outcome was compared with their results of both experimental and numerical simulation. Then, a packed bed structure was generated by DEM method and factors affecting the liquid distribution were investigated in the complex region.…”

Section: Numerical Setupmentioning

confidence: 99%

Computational Investigation of Liquid Holdup and Wetting Efficiency Inside Trickle Bed Reactors with Different Catalyst Particle Shapes

et al. 2020

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Liquid holdup and wetting efficiency are essential parameters for design of trickle bed reactors. Both parameters play an important role in reactor performance including pressure drop, conversion, and heat transfer. Empirical formulas are usually employed to calculate liquid holdup and wetting efficiency. However, factors such as particle shape and the wetting ability of liquid on the particle surface are not described clearly in traditional formulas. In this paper, actual random packing was built by DEM and CFD simulations were performed to investigate the factors affecting liquid holdup and wetting efficiency in trickle bed reactors, including particle shape, surface tension, contact angle, liquid viscosity, liquid density, liquid, and gas superficial velocity. Detailed fluid flow and liquid-solid interaction were described by VOF model. Four different particle shapes were investigated. It showed the particle shape has great effect and the 4-hole cylinder packing gained both highest liquid holdup and wetting efficiency. The overall simulations gave a detailed description of phase interactions and fluid flow in the voids between catalyst particles and these results could give further guidance for the design and operation of trickle bed reactors.

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Computational study of flow and heat transfer in fixed beds with cylindrical particles for low tube to particle diameter ratios

Cited by 54 publications

References 50 publications

The influence of random packed column parameters on the liquid holdup and interfacial area

The influence of random packed column parameters on the liquid holdup and interfacial area

Review on the structure of random packed‐beds

Computational Investigation of Liquid Holdup and Wetting Efficiency Inside Trickle Bed Reactors with Different Catalyst Particle Shapes

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