Liquid flow pattern transition, droplet diameter and size distribution in the cavity zone of a rotating packed bed: A visual study

Sang, Le; Luo, Yong; Chu, Guang‐Wen; Zhang, Jingpeng; Xiang, Yang; Chen, Jianfeng

doi:10.1016/j.ces.2016.10.044

Cited by 119 publications

(81 citation statements)

References 23 publications

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“…Further, there will also be an acceleration of coalescence–dispersion frequency among liquid elements, thus intensifying molecular collisions. Moreover, high rotational speed generates huge centrifugal force, which reduces the droplets and liquid film inside the packing to small sizes, resulting in a large surface area and enhanced micromixing process . Furthermore, as the rotational speed increases, liquid is sucked in and poured out of the packing bed at a higher speed, which leads to more cycles in RPB packing and further improves micromixing efficiency.…”

Section: Resultsmentioning

confidence: 99%

HiGee Strategy toward Rapid Mass Production of Porous Covalent Organic Polymers with Superior Methane Deliverable Capacity

Zhang

Liu

Luo

et al. 2020

Adv Funct Materials

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High porosity with well‐defined molecular reticulation along with strong stability is desired for natural gas delivery. The catalyzed Yamamoto‐type Ullmann cross‐coupling route with efficient terminal halogen removal capability is currently used to prepare porous organic materials with high specific surface area as well as ultrahigh hydrothermal stability. As a typical fast coupling reaction, the traditional stirred solvothermal approach shows the limitation of macroscopic reaction kinetics due to the increasing viscosity of the reaction mixture with the molecular network growth until it turns to a jelly‐like consistency. Herein, a high‐gravity chemical synthetic strategy to achieve rapid and economical preparation of a class of, but not limited to, covalent organic polymers (COPs) with high hydrothermal stability using the Ullman cross‐coupling route is described. The viscous fluid is vigorously split into homogeneous microdroplets through the rotating packed bed (RPB) under the HiGee environment. The HiGee approach shortens the traditional reaction time from 600 to 15 min as well as reduces the usage of high‐cost nickel (0) catalyst by 40 wt%. Specially, the COP‐10 obtained with the HiGee approach displays an excellent deliverable methane capacity of 415 cm3 STP g−1 at 298 K with working pressures 5–65 bar, which is higher than that of most reported porous organic materials.

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Section: Resultsmentioning

confidence: 99%

HiGee Strategy toward Rapid Mass Production of Porous Covalent Organic Polymers with Superior Methane Deliverable Capacity

Zhang

Liu

Luo

et al. 2020

Adv Funct Materials

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“…Moreover, Li [5] investigated the effect of a various operating conditions especially for the layer numbers on the liquid patterns and drew a conclusion that the droplet was the main pattern in packing. As for recent research, Sang [6] indicated a criterion to distinguish two typical liquid patterns: Ligament flow and droplet flow. The Computational fluid dynamics is called CFD for short, which is a combination of computer and numerical techniques.…”

Section: Introductionmentioning

confidence: 91%

Droplet Characteristics of Rotating Packed Bed in H2S Absorption: A Computational Fluid Dynamics Analysis

Wang

Yang

et al. 2019

Processes

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Rotating packed bed (RPB) has been demonstrated as a significant and emerging technology to be applied in natural gas desulfurization. However, droplet characteristics and principle in H2S selective absorption with N-methyldiethanolamine (MDEA) solution have seldom been fully investigated by experimental method. Therefore, a 3D Eulerian–Lagrangian approach has been established to investigate the droplet characteristics. The discrete phase model (DPM) is implemented to track the behavior of droplets, meanwhile the collision model and breakup model are employed to describe the coalescence and breakup of droplets. The simulation results indicate that rotating speed and radial position have a dominant impact on droplet velocity, average residence time and average diameter rather than initial droplet velocity. A short residence time of 0.039–0.085 s is credited in this study for faster mass transfer and reaction rate in RPB. The average droplet diameter decreases when the initial droplet velocity and rotating speed enhances. Restriction of minimum droplet diameter for it to be broken and an appropriate rotating speed have also been elaborated. Additional correlations on droplet velocity and diameter have been obtained mainly considering the rotating speed and radial position in RPB. This proposed formula leads to a much better understanding of droplet characteristics in RPB.

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“…In order to assess the configuration of the liquid inlet on the liquid distribution in the REU, different numbers of evenly distributed nozzles with the same total liquid flow rate and the same diameter are investigated. The diameter of the nozzle is set as 1 mm, which is close to the diameter of the droplets in the RPB as observed in the experiments (Sang et al, 2017) and the number of nozzles tested ranges from 5 to 14. The calculation domain is divided evenly into 6 regions along the radial direction from the liquid inlet boundary to the outlet boundary.…”

Section: Effect Of the Liquid Inlet Configurationmentioning

confidence: 99%

“…At present, different measuring techniques have been used to measure the fluid dynamics in RPBs. These include (i) noninvasive measuring techniques, such as the high-speed photography (Burns and Ramshaw, 1996;Guo et al, 2000;Sang et al, 2017), particle image velocimetry (PIV) (Yang et al, 2011), X-ray computed tomography (Yang et al, 2015a), and (ii) invasive measuring techniques, such as tracking the liquid trajectories in the RPB by inserting papers (Yan et al, 2012) or wrapping paper tapes (Guo et al, 2014).…”

Section: Introduction Of the Rpb And Its Investigationmentioning

confidence: 99%

A mesoscale 3D CFD analysis of the liquid flow in a rotating packed bed

Xie

Ding

et al. 2019

Chemical Engineering Science

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Rotating packed beds (RPBs), as a type of process intensification technology, are promising to be employed as high-efficiency CO 2 absorbers. However, the detailed understanding of the liquid flow in the RPB is still very limited. The complex and dense packing of the bed and the multiscale of the RPB make it very difficult to perform numerical simulations in detail, in particular for full 3D simulations. In this paper, a mesoscale 3D CFD modelling approach is proposed which can be used to investigate the liquid flow in both laboratory-and large-scale RPBs in detail and accuracy. A 3D representative elementary unit of the RPB has been built and validated with experimental observations, and then it is employed to investigate the gas-liquid flows at different locations, across a typical RPB, so that the overall characteristics of the liquid flow in the RPB can be assembled. The proposed approach enables the detailed prediction of the liquid holdup, droplets formation, effective interfacial area, wetted packing area and specific surface area of the liquid within real 3D packing structures throughout the bed. New correlations to predict the liquid holdup, effective interfacial area, and specific surface area of the liquid are proposed, and the sensitivities of these quantities to the rotational speed, liquid flow rate, viscosity and contact angle have been investigated. The results have been compared with experimental data, previous correlations and theoretical values and it shows that the new correlations have a good accuracy in predicting these critical quantities. Further, recommendations for scale-up and operation of an RPB for CO 2 capture are provided. This proposed model leads to a much better understanding of the liquid flow behaviours and can assist in the RPB optimisation design and scaling up.

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Liquid flow pattern transition, droplet diameter and size distribution in the cavity zone of a rotating packed bed: A visual study

Cited by 119 publications

References 23 publications

HiGee Strategy toward Rapid Mass Production of Porous Covalent Organic Polymers with Superior Methane Deliverable Capacity

HiGee Strategy toward Rapid Mass Production of Porous Covalent Organic Polymers with Superior Methane Deliverable Capacity

Droplet Characteristics of Rotating Packed Bed in H2S Absorption: A Computational Fluid Dynamics Analysis

A mesoscale 3D CFD analysis of the liquid flow in a rotating packed bed

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