Equivalent annular model of a multitubular shell‐side (MSS) fixed‐bed reactor

Li, Haoming; Hudgins, R. R.; Chang, Kun Soo

doi:10.1002/aic.690370803

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…In relatively recent years, research on beds of cylindrical packings and reactors with embedded tubes has increased (Schneider et al, 1990;Li et al, 1991;Nolan and Kavanagh, 1995;Zou and Yu, 1996;Dixon et al, 2006;Zhang et al, 2006).…”

Section: Results and Analysismentioning

confidence: 99%

Digital predictions of complex cylinder packed columns

Caulkin

Ahmad

Fairweather

et al. 2009

Computers & Chemical Engineering

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A digital computational approach has been developed to simulate realistic structures of packed beds. The underlying principle of the method is digitisation of the particles and packing space, enabling the generation of realistic structures. Previous publications (Caulkin et al., 2006(Caulkin et al., , 2007 have demonstrated the ability of the code in predicting the packing of spheres. For cylindrical particles, however, the original, random walk-based code proved less effective at predicting bed structure. In response to this, the algorithm has been modified to make use of collisions to guide particle movement in a way which does not sacrifice the advantage of simulation speed. Results of both the original and modified code are presented, with bulk and local voidage values compared with data derived by experimental methods. The results demonstrate that collisions and their impact on packing structure cannot be disregarded if realistic packing structures are to be obtained.

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Section: Results and Analysismentioning

confidence: 99%

Digital predictions of complex cylinder packed columns

Caulkin

Ahmad

Fairweather

et al. 2009

Computers & Chemical Engineering

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“…The ammonia synthesis was selected as a case study. The Equivalent Annular Model proposed by Li et al (1991) was adopted to represent the shell-side catalyst bed. According to this model, the cross-sectional area of the catalyst bed is considered to be subdivided into identical annular areas centered around each cooling tube.…”

Section: Mathematical Modelmentioning

confidence: 99%

Steady‐state multiplicity in cocurrently cooled autothermal reactors

1997

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“…Therefore, the radial void fraction profiles cannot strictly be mirrored, as proposed elsewhere . Nonetheless, additional wall channeling occurs at the outer wall of the thermocouple well and, hence, influences fluid flow, lateral mixing, heat and mass transfer, as well as chemical reactions. − In addition, the insertion of a thermowell changes the pressure drop over, or, if the head pressure remains constant, the flow rate through the reactor. Pseudo-homogeneous continuum models were developed taking into account the effect of thermowells, mainly by additional heat transfer resistances at the thermowell wall. − Finally, an empirical correlation based on such a two-dimensional (2D) model was developed to relate the temperature measured in tubes containing concentric axial thermowells to tubes without thermowells .…”

Section: Introductionmentioning

confidence: 99%

How Temperature Measurement Impacts Pressure Drop and Heat Transport in Slender Fixed Beds of Raschig Rings

et al. 2022

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The axial temperature profile of a packed bed is often measured by thermocouples placed either directly in the bed or inside a thermowell centered in the reactor tube. Quantifying the impact of the thermocouple well on fluid flow, heat transport, and consequently on the measured temperatures is still an unresolved challenge for lab-scale reactors but especially, and even more so for multitubular reactors in industry. Particle-resolved computational fluid dynamics (PRCFD) simulations are a suitable approach to investigate the changes in transport phenomena exerted by inserting thermocouple wells into packed beds because they take into account the local packed bed structures. In this study, PRCFD simulations are performed based on design of simulation experiments (DoSE). The effect of the thermowell diameter and its thermal conductivity on the deviations between packed beds with and without thermowells is statistically quantified for characteristic integral quantities like pressure drop and tube wall-bed Nusselt number. The axial temperature profiles inside the thermowells can be computed efficiently with reasonably accuracy applying the Nusselt number correction as derived in this study from the DoSE in a one-dimensional pseudo-homogeneous energy balance.

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Equivalent annular model of a multitubular shell‐side (MSS) fixed‐bed reactor

Cited by 6 publications

References 10 publications

Digital predictions of complex cylinder packed columns

Digital predictions of complex cylinder packed columns

Steady‐state multiplicity in cocurrently cooled autothermal reactors

How Temperature Measurement Impacts Pressure Drop and Heat Transport in Slender Fixed Beds of Raschig Rings

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