Investigation of the liquid mixing characteristic of an external-loop hybrid fluidized-bed airlift reactor

Prończuk, Mateusz; Bizon, Katarzyna

doi:10.1016/j.ces.2019.115231

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…[13] Therefore, the Peclet number (Pe), describing the ratio between convection and diffusion, could be employed in the design of the HSCs. The Pe is expressed as follows [86][87][88][89]…”

Section: Ideal Channelsmentioning

confidence: 99%

Hierarchically Structured Components: Design, Additive Manufacture, and Their Energy Applications

Wang

Xuan

Zhang

et al. 2021

Adv Materials Technologies

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term solutions are urgently needed before adequate supply of the renewable energy. [1,2] Improvement of efficiency in the energy production and consumption processes is a key factor to address these problems. Meanwhile, the large reaction rate is a key factor to meet the industrial energy requirements. [1][2][3][4][5] Mass transport intensification is an effective method to improve the efficiency and reaction rate in the adsorptions, chemical reactions, and electrochemical reactions, which plays crucial roles in the gas (H 2 , CH 4 , CO 2 , etc.) storage, [6,7] energy conversion, [8] and energy storage. [3,9,10] Recently, novel batteries [2,3,[11][12][13] and microreactors [8,[14][15][16][17][18] for the gas (H 2 , CH 4 , CO 2 , etc.) storage [6,7] and energy conversion [8] have been developed to meet the requirements of high efficiency and rates. In these devices, the mass transport intensification is particularly important to acquire the high selectivity, large reaction rate, great conversion efficiency. [2,8,19,20] The mass transfer steps in the monolithic adsorbents, structured catalysts, and shaped electrodes are similar. Therefore, it is possible to use an identical term to describe the monolithic adsorbents, structured catalysts, and shaped electrodes for convenience to discuss the mass transfer processes. Herein, we use the hierarchically structured components (HSCs) to describe the structures which are comprised of designed channels and matrix between channels, where the matrix is made from functional materials (ceramics, carbon, metals, etc.) with pores in the size from nanometer to sub-millimeters, as illustrated in Figure 1a. In the flow batteries and fuel cells, the assembly of bipolar plate and electrode is regarded as HSC.Generally, the reactants undergo four steps (distribution, adsorption, acceleration, and reaction) in the HSC, as shown in Figure 1b-e. The distribution starts as soon as the reactant flows into the inlet. In this step, the reactant is distributed across the HSC through the designed channels, as shown in Figure 1b. [21,22] Subsequently the fluid is adsorbed by the macropores (>50 nm) which act as buffers for the reactants in the matrix, shown in Figure 1c. [23] As shown in Figure 1d,e, the reactants are accelerated by the mesopores (2-50 nm) and transferred to the micropores (<2 nm) which provide high surface area for the active sites. [23][24][25] After reaction at the active sites, the products are transferred by the mesopores and macropores to the outlet, successively. [26,27] Therefore, the Pursuing high energy efficiency and reaction rate is an effective direction in mitigating the energy and climate crisis. Mass transfer intensification is a powerful approach to enhance the energy efficiency and reaction rate in the energy conversion and storage processes. The nature-inspired channels are outstanding tools to uniformly distribute the reactants, fast remove products, and reduce the diffusion distance for mass transfer intensification in monolithic adsorbents, structured catal...

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“…[13] Therefore, the Peclet number (Pe), describing the ratio between convection and diffusion, could be employed in the design of the HSCs. The Pe is expressed as follows [86][87][88][89]…”

Section: Ideal Channelsmentioning

confidence: 99%

Hierarchically Structured Components: Design, Additive Manufacture, and Their Energy Applications

Wang

Xuan

Zhang

et al. 2021

Adv Materials Technologies

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“…The influence of the gas distributor on the local hydrodynamic behaviour of an external loop airlift reactor was investigated in the study of Lin et al [16]. Experimental study of the liquid mixing characteristic of an external-loop airlift reactor with a fluidized-bed was performed in the study of Pronczuk and Bizon [17].…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the hydrodynamics and mass transfer in the external loop airlift reactor

Kojić

Krulj

et al. 2022

CI&CEQ

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The objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift reactor (ELAR). The ELAR was operated in three cases: different inlet velocities of fluids, different alcohols solutions (water, 0.5% methanol, 0.5% ethanol, 0.5% propanol and 0.5% butanol) and different concentration of methanol in solutions (0%, 0.5%, 1%, 2% and 5%). The influence of superficial gas velocity and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAR was studied. Experimentally, the gas hold-up, liquid velocities and volumetric mass transfer coefficient values in the riser and the downcomer were obtained from the literature source. A computational fluid dynamics (CFD) model was developed, based on two-phase flow, investigating different liquids regarding surface tension, assuming the ideal gas flow, applying the finite volume method and Eulerian-Eulerian model. The volumetric mass transfer coefficient was determined using CFD model, as well as artificial neural network model. The effects of liquid parameters and gas velocity on the characteristics of the gas-liquid mass transfer were simulated. These models were compared with appropriate experimental results. CFD model successfully succeed to simulate the influence of different alcohols regarding the number of C-atoms on hydrodynamics and mass transfer.

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“… 1 − 5 The advantages of the ILALR are its large capacity, simple structure without moving parts, easy operation, efficient mixing, and long residence time. 6 − 8 Hydrodynamic properties such as gas holdup, liquid circulating velocity, and bubble size distribution (BSD) are necessary for the design and scale-up of the ILALRs. 6 , 9 For example, gas holdup is a key factor affecting the mass transfer performance of ILALRs.…”

Section: Introductionmentioning

confidence: 99%

“… 6 − 8 Hydrodynamic properties such as gas holdup, liquid circulating velocity, and bubble size distribution (BSD) are necessary for the design and scale-up of the ILALRs. 6 , 9 For example, gas holdup is a key factor affecting the mass transfer performance of ILALRs. A high gas holdup indicates a superior mixing capacity and high gas–liquid mass transfer rate in ILALRs.…”

Section: Introductionmentioning

confidence: 99%

“…An internal loop airlift reactor (ILALR) is a type of pneumatically agitated vessel that is widely used in several applications such as chemical, petrochemical, bioprocessing, and water treatment processes. − The advantages of the ILALR are its large capacity, simple structure without moving parts, easy operation, efficient mixing, and long residence time. − Hydrodynamic properties such as gas holdup, liquid circulating velocity, and bubble size distribution (BSD) are necessary for the design and scale-up of the ILALRs. , For example, gas holdup is a key factor affecting the mass transfer performance of ILALRs. A high gas holdup indicates a superior mixing capacity and high gas–liquid mass transfer rate in ILALRs.…”

Section: Introductionmentioning

confidence: 99%

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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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Investigation of the liquid mixing characteristic of an external-loop hybrid fluidized-bed airlift reactor

Cited by 9 publications

References 24 publications

Hierarchically Structured Components: Design, Additive Manufacture, and Their Energy Applications

Hierarchically Structured Components: Design, Additive Manufacture, and Their Energy Applications

Numerical study of the hydrodynamics and mass transfer in the external loop airlift reactor

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

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