CFD Prediction of Hydrodynamics in High-Pressure Trickle Bed Reactor

Abstract

Most commercial trickle-bed reactors (TBRs) normally operate at high pressures. This study presents the initial development of a comprehensive CFD based model to predict pressure drop and liquid saturation in TBRs under high pressure. A two-phase Eulerian CFD model envisaging the flow domain as porous region for evaluating these hydrodynamic parameters even for high pressure operations, has been proposed. Evaluation of model predictions have been carried out with reported experimental data, collected under varied set of operating conditions. All the comparisons lead to the favorable implementation this less computationally intensive, yet first-principle based CFD model to forecast the two-phase pressure drop and liquid saturation for TBRs operating at high pressures.

CFD Analysis of BED Textural Characteristics on TBR Behavior: Hydrodynamics and Scaling-up

“…Models S1, S2 and S3 give excellent predictions for pressure drop, with MARE below 3.1 %; In fact, the conventional model (S1) leads to excellent predictions with a MARE of 1.9 % when the holdups are equalized, and of 1.95 % when mass velocities are equalized. This implies 25 % better accuracy in predicting dimensionless pressure drops in operation at low pressure and an improvement of five times at high pressures operation, in comparison with literature works (Al-Dahhan and Dudukovic 1994;Atta, Shantanu, and Nigam 2009;Holub, Dudukovic, and Ramachandran 1992;Iliuta and Larachi 1999;Mitra 2011;Solomenko et al 2015). While when the Reynolds number and hourly space velocities are used to compare both reactors with S1 IMEM model, the MARE´s obtained are 62 % and 90.2 % respectively.…”

Bed structure and its impact on liquid distribution in a trickle bed reactor

“…As the commercial reactors are generally operated in trickle flow (continuous phase: gas, semi‐continuous phase: liquid), there exist various bed scale and particle scale phenomenon, which needs to be addressed 1,2,8 . For such operating conditions, gravitational, inertial, viscous, and capillary forces, all play an important role and cannot be neglected while performing a theoretical analysis 9 . In this particular regime, the catalyst bed may be completely or partially wetted at the bed scale or the particle scale 7–9 .…”

“…1,2,8 For such operating conditions, gravitational, inertial, viscous, and capillary forces, all play an important role and cannot be neglected while performing a theoretical analysis. 9 In this particular regime, the catalyst bed may be completely or partially wetted at the bed scale or the particle scale. [7][8][9] Flow is characterized as film or filament flow based on operating conditions, packing configuration, and fluid flow properties; liquid may traverse the bed in the form of rivulets or may get stuck in the form of pendular structures, pockets or bridges as shown in Figure 1.…”

“…9 In this particular regime, the catalyst bed may be completely or partially wetted at the bed scale or the particle scale. [7][8][9] Flow is characterized as film or filament flow based on operating conditions, packing configuration, and fluid flow properties; liquid may traverse the bed in the form of rivulets or may get stuck in the form of pendular structures, pockets or bridges as shown in Figure 1. 1 These structures may be beneficial or detrimental based on the reaction type, whether it is liquid or gas limited.…”