Integration of phase distribution from gamma-ray tomography technique with monolith reactor scale modeling

Roy, Shaibal; Kamalanathan, Premkumar; Al‐Dahhan, Muthanna H.

doi:10.1016/j.ces.2018.12.053

Cited by 7 publications

(8 citation statements)

References 29 publications

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“…where ω is the weight vector, 1 /2 ω 2 is the model complexity, and C is the penalty factor, ε is insensitive loss, ξ i , ξ * i is the relaxation variable. The Lagrange equation is used to solve this quadratic programming problem, and it is converted into the dual optimization corresponding to Equations ( 5) and (6).…”

Section: Support Vector Regression and Particle Swarm Optimizationmentioning

confidence: 99%

“…However, there is a possibility of flow redistribution at the exit of the bed [2][3][4]. To overcome this disadvantage, several groups have focuses on the use of tomographic measurements using photon attenuation (x-ray and γ-ray tomography), magnetic resonance imagining, and electric tomographic techniques, which provide more quantitative flow distribution information [5][6][7][8][9]. With the drawback of a high cost and unsafety, the performance of these techniques depends on the complexity of the reconstruction algorithms.…”

Section: Introductionmentioning

confidence: 99%

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A Closed-Loop Optimized System with CFD Data for Liquid Maldistribution Model

Zhang

et al. 2020

Processes

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For the simulation of a trickle-bed reactor (TBR) in coal and oil refining, modeling the liquid maldistribution of the gas-liquid distributor incurs enormous pre-processing work and bears a huge computational cost. A closed-loop optimized system with computational fluid dynamic (CFD) data is therefore proposed for the first time in this paper. A fast prediction model based on support vector regression (SVR) is developed to simplify the modeling of the liquid flow rate in TBRs. The model uses CFD simulation results to determine an optimized set of structural parameters for the gas-liquid distributor in TBRs. In order to obtain an accurate SVR model quickly, the particle swarm optimization (PSO) algorithm is employed to optimize the SVR parameters. Then, the structural parameters corresponding to the minimum liquid maldistribution factor are calculated using the response surface methodology (RSM) based on the hybrid PSO-SVR model. The CFD validation results show a good agreement with the values predicted by RSM, with liquid maldistribution factors of 0.159 and 0.162, respectively.

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Section: Support Vector Regression and Particle Swarm Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Closed-Loop Optimized System with CFD Data for Liquid Maldistribution Model

Zhang

et al. 2020

Processes

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“…Coarse open-cell foams were diagnosed with an anomalous spreading behavior which was insufficient to counterbalance liquid maldistribution. Roy et al 13 used γ-ray computed tomography to investigate the relationship of the phasic cross-section distribution with operating conditions, liquid surface tension, and gas density for monolith packings. Large superficial liquid velocities and elevated gas densities favored approaching phase uniformity with a minor effect of liquid surface tension.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Resilience against Liquid Maldistribution of Monolith Packings under Offshore Floating Conditions

Zhang

Dashliborun

Taghavi

et al. 2019

Ind. Eng. Chem. Res.

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The study provides insights for adapting commercially available packings to work on floating vessels in the marine context aiming at preserving performances similar to land-based packed-bed reactors. Specifically, liquid distribution for cocurrent gas–liquid downflow (U g = 0.0065–0.131 m/s and U l = 0.001–0.0078 m/s) inside monolith packings embarked on a hexapod emulator was compared against glass-bead containing trickle bed and open-cell foam packings using wire-mesh sensors under vertical, inclined, and rolling column conditions. Sensitivity of the tested internals with regard to liquid maldistribution was diagnosed and analyzed in terms of a maldistribution factor for the vertical/inclined and rolling columns. Liquid maldistribution was found to prevail at high gas and low liquid superficial velocities for the tested three packings regardless of column conditions. Monolith packed beds demonstrated superior robustness to counteract liquid maldistribution induced by bed static inclinations and roll motions. The glass-bead packed bed was susceptive to column inclination and rolling and suffered appreciable gas/liquid stratified flow leading to a loss of transverse liquid uniformity. Open-cell coarse foams equally failed as they were unable to preserve a homogeneous liquid distribution due to their poor radial spreading.

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“…It should be noted that Roy and Al‐Dahhan reported that uniform phase distribution was achieved within the limited range of operating conditions within the Taylor flow regime. Using actual phase distribution data from experiments, Schubert et al and Roy et al reported that the performance of the monolith has a strong dependence on the phase distribution using modelling studies. However, there is no experimental study available that confirms and quantifies the effect of the degree of maldistribution on the performance of the monolith reactor.…”

Section: Introductionmentioning

confidence: 99%

“…However, there is no quantitative information available in the literature on the effect of maldistribution on catalyst utilization. Further, Roy et al reported that with an increase in the pressure, the uniformity increases and the liquid fraction decreases across the channels. However, the effect of pressure at maldistributed and uniform flow conditions is not available in the literature, which is of interest for the intensification/improvement of the performance of monolith reactors.…”

Section: Introductionmentioning

confidence: 99%

Effect of phase maldistribution on performance of two‐phase catalytic monolith reactor and its comparison with trickle bed reactor

et al. 2019

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Monolith reactors are widely considered as an alternative to the conventional trickle bed reactor. For the commercial deployment of monolith reactors, comparative performance studies are required. Reliable comparative and performance studies require a detailed understanding of the effect of phase distribution/maldistribution on the performance studies. In this work, performance and comparative studies were carried out in a relatively large column that was 4.8 cm in diameter. Experiments were performed in the same conditions that were used in studies for which phase distribution data were available. Since the properties of the catalyst used were different in both the reactors, the apparent kinetics were studied to facilitate the comparison. The hydrogenation of alpha‐methyl styrene (AMS) was used as a test reaction. From the performance studies, it was found that the effect of maldistribution on the performance was stronger than the catalyst availability. From the comparative studies, it was found that the monolith reactor with maldistributed flow conditions provides higher productivity than the trickle bed reactor.

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Integration of phase distribution from gamma-ray tomography technique with monolith reactor scale modeling

Cited by 7 publications

References 29 publications

A Closed-Loop Optimized System with CFD Data for Liquid Maldistribution Model

A Closed-Loop Optimized System with CFD Data for Liquid Maldistribution Model

Assessment of the Resilience against Liquid Maldistribution of Monolith Packings under Offshore Floating Conditions

Effect of phase maldistribution on performance of two‐phase catalytic monolith reactor and its comparison with trickle bed reactor

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