Modeling transport phenomena and reactions in a pilot slurry airlift loop reactor for direct coal liquefaction

Huang, Qingshan; Zhang, Weipeng; Yang, Chao

doi:10.1016/j.ces.2015.01.003

Cited by 32 publications

(11 citation statements)

References 42 publications

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“…Airlift Reactors (ALR) attract more and more interests in many process applications, such as syngas fermentation [1], direct coal liquefaction [2] and waste water/gas treatment [3]. The advantages of ALR over bubble columns include enhanced mixing efficiency and good suspension of particles due to improved liquid circulation.…”

Section: Introductionmentioning

confidence: 99%

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Han

Sha

Лаари

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-Hydrodynamics of an AirLift Reactor (ALR) with tap water and non-Newtonian fluid was studied experimentally and by numerical simulations. The Population Balance Model (PBM) with multiple breakup and coalescence mechanisms was used to describe bubble size characteristics in the ALR. The interphase forces for closing the two-fluid model were formulated by considering the effect of Bubble Size Distribution (BSD). The BSD in the ALR obtained from the coupled Computational Fluid Dynamics (CFD)-PBM model was validated against results from digital imaging measurements. The simulated velocity fields of both the gas and liquid phases were compared to measured fields obtained with Particle Image Velocimetry (PIV). The simulated results show different velocity field profile features at the top of the ALR between tap water and nonNewtonian fluid, which are in agreement with experiments. In addition, good agreement between simulations and experiments was obtained in terms of overall gas holdup and bubble Sauter mean diameter. NOMENCLATURE SymbolsVolume fraction of gas/liquid phase, 1 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Section: Introductionmentioning

confidence: 99%

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Han

Sha

Лаари

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…Lift force has been proven to be an important force for the simulation of the bubbly flow in bubble columns, airlift loop reactors, and some other gas–liquid systems . It can be calculated by where C l is the lift coefficient, and it can be approximated by different models.…”

Section: Simulation Methodologymentioning

confidence: 99%

“…Lift Force Models. Lift force has been proven to be an important force for the simulation of the bubbly flow in bubble columns, 37 airlift loop reactors, 38 and some other gas−liquid systems. 39 It can be calculated by…”

Section: Methodsmentioning

confidence: 99%

Modeling of Microbubble Flow and Coalescence Behavior in the Contact Zone of a Dissolved Air Flotation Tank Using a Computational Fluid Dynamics–Population Balance Model

Chen

Yang

Geng

et al. 2019

Ind. Eng. Chem. Res.

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Computational fluid dynamics coupled with a population balance model was implemented to resolve microbubble flow and coalescence behavior in the contact zone of a dissolved air flotation tank. Influences of two important interphase forces and coalescence models were examined. The results indicated that the lift force has negligible influence on gas holdup, while incorporating appropriate turbulent dispersion force model can substantially improve the predicted gas holdup and make it consistent with experimental data. The population balance model considering both the eddy-capture and velocity gradient mechanisms could accurately predict the bubble diameter and its size distribution. The relative difference between the simulated and the measured mean bubble diameter is lower than 10.2%. It was also found that bubble coalescence mainly happens below the nozzle inlet and around the nozzle inlet pipe, and the bubble coalescence was enhanced by the flow direction transition and nonuniform gas holdup distribution in these two regions, respectively.

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“… 10 − 13 The hydrodynamics of the ILALRs have been studied mainly via experiment 12 , 14 − 19 and computational fluid dynamics (CFD) simulation. 20 − 27 In the experimental studies, gas holdup, mixing time, bubble size, residence time distribution, and liquid circulating velocity can be measured by invasive 7 or non-invasive methods. 17 , 18 In recent times, because of the development of computing techniques, CFD is extensively used to provide the details of the hydrodynamics inside the ILALR.…”

Section: Introductionmentioning

confidence: 99%

“…A high gas holdup indicates a superior mixing capacity and high gas–liquid mass transfer rate in ILALRs. Therefore, various high-efficient ILALRs were developed from the perspective of increasing the gas holdup. − The hydrodynamics of the ILALRs have been studied mainly via experiment ,− and computational fluid dynamics (CFD) simulation. − In the experimental studies, gas holdup, mixing time, bubble size, residence time distribution, and liquid circulating velocity can be measured by invasive or non-invasive methods. , In recent times, because of the development of computing techniques, CFD is extensively used to provide the details of the hydrodynamics inside the ILALR.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulation of Hydrodynamics in a Two-Stage Internal Loop Airlift Reactor with Contraction-Expansion Guide Vane

et al. 2021

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Global circulation and liquid back mixing adversely affect the continuous production of a multistage internal airlift loop reactor. A contraction-expansion guide vane (CEGV) is proposed and combined with a two-stage internal loop airlift reactor (TSILALR) to suppress the liquid back mixing between stages. A computational fluid dynamics (CFD) simulation is conducted to evaluate the performance of the CEGV in the TSILALR. The bubble size distribution and turbulent flow properties in the TSILALR are considered in the CFD simulation by using the population balance model and RNG k - ε turbulence model. The CFD model is validated against the experimental results. The deviations in the gas holdup and mean bubble diameter between the simulation and experimental results are less than 8% and 6%, respectively. The streamlines, flow pattern, bubble size distribution, and axial liquid velocity in the TSILALRs with and without the CEGV at superficial velocities of 0.04 and 0.08 m/s are obtained by CFD simulation. It has been shown that the CEGV generated local circulation flows at each stage instead of a global circulation flow in the TSILALR. The average global gas holdup in the TSILALR with a CEGV increased up to 1.98 times. The global gas holdup increased from 0.045 to 0.101 and the average axial velocity in the riser decreased from 0.314 to 0.241 m/s when the width of the CEGV increased from 50 to 75 mm at the superficial gas velocity of 0.08 m/s.

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Modeling transport phenomena and reactions in a pilot slurry airlift loop reactor for direct coal liquefaction

Cited by 32 publications

References 42 publications

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Modeling of Microbubble Flow and Coalescence Behavior in the Contact Zone of a Dissolved Air Flotation Tank Using a Computational Fluid Dynamics–Population Balance Model

Computational Fluid Dynamics Simulation of Hydrodynamics in a Two-Stage Internal Loop Airlift Reactor with Contraction-Expansion Guide Vane

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