Mixing Time, Homogenization Energy and Residence Time Distribution in a Gas-Induced Contactor

Jafari, M.; Soltan, Jafar

doi:10.1205/cherd.04207

Cited by 24 publications

(16 citation statements)

References 19 publications

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“…In some cases this can be difficult to find directly from a plot of E versus t because of the fine scale around the endpoint. Brown et al [6][7][8] had proposed that mixing time is the time after the injection of tracer, when tracer concentration of normalized curve is within ± 5 % of the final equilibrium value. In order to obtain accurate value of mixing time from the measured curves, variance with respect to C(f) is plotted as a function of time and mixing time corresponding to 0.05 of variance is obtained.…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Goswami

Biswal

Samantray

et al. 2014

J Radioanal Nucl Chem

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Mixing times and holdup of solids were measured in a gas-solid fluidized bed using radiotracer technique. Sand and air were used as solid and gas phase, respectively in the fluidized bed. Gold-198 labeled sand particles were used as radiotracer for mixing time measurement at different operating conditions and 137 Cs sealed source was used for holdup measurement at different axial and radial positions. The experiments were conducted at different operating conditions. The measured mixing times ranged from 1.4 to 21 s at different conditions. It was observed that at a particular bed height, the mixing time initially decreases with increasing gas velocity and tend to become constant at higher gas velocities. However, mixing time increases with increasing bed height. The holdup fraction of solid was found to be more towards the wall compared to the centre of the column. The study provided inputs to improve the existing design, design of a new system and scale-up of the process.

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Section: Data Analysis and Resultsmentioning

confidence: 99%

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Goswami

Biswal

Samantray

et al. 2014

J Radioanal Nucl Chem

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“…Moreover, Bouaifi and Roustan [16] discussed the experimental results on the power consumption, mixing time, and mixing energy in a non-standard vessel equipped with various axial and mixed dual-impeller configurations. The mixing characteristics (e.g., mixing time, homogenization energy, and residence time distribution) of a gas-induced reactor with two 45 • -pitched downward blade turbines were analyzed by Jafari and Mohammadzadeh [17]. In addition, oxygen mass transfer characteristics for various twin-and single-impeller systems (e.g., Rushton turbine, pitched 4-, and 2-blade impellers) were studied by Karimi et al [18], while the power consumption and the mixing time for the non-baffled agitated vessel with a double impeller were measured by Hiraoka et al [19], who later discussed the best set-up position and the combination of impellers.…”

Section: Feature Descriptionmentioning

confidence: 99%

Hydrodynamics and Mass Transfer Analysis in BioFlow® Bioreactor Systems

et al. 2020

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Biotechnological processes involving the presence of microorganisms are realized by using various types of stirred tanks or laboratory-scale dual-impeller commercial bioreactor. Hydrodynamics and mass transfer rate are crucial parameters describing the functionality and efficiency of bioreactors. Both parameters strictly depend on mixing applied during bioprocesses conducted in bioreactors. Establishing optimum hydrodynamics conditions for the realized process with microorganisms maximizes the yield of desired products. Therefore, our main objective was to analyze and define the main operational hydrodynamic parameters (including flow field, power consumption, mixing time, and mixing energy) and mass transfer process (in this case, gas–liquid transfer) of two different commercial bioreactors (BioFlo® 115 and BioFlo® 415). The obtained results are allowed using mathematical relationships to describe the analyzed processes that can be used to predict the mixing process and mass transfer ratio in BioFlo® bioreactors. The proposed correlations may be applied for the design of a scaled-up or scaled-down bioreactors.

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“…Mixing time (tm) is the characteristic parameter used to investigate the performance of stirred tank reactors. Mixing time is defined as the period of time necessary to achieve the desired level of homogeneity in a given vessel (Jafari et al, 2005)…”

Section: The Mixing Timementioning

confidence: 99%

Enzymatic hydrolysis at high dry matter content: The influence of the substrates’ physical properties and of loading strategies on mixing and energetic consumption

Battısta

Almendros

Rousset

et al. 2018

Bioresource Technology

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The present work investigates the impact of the physical properties and loading strategies of wheat straw and miscanthus on enzymatic hydrolysis at high DM concentration. Three parameters have been chosen to evaluate the enzymatic hydrolysis performance: (i) the mixing time, (ii) the energetic mixing consumption and (iii) the glucose concentration. It was demonstrated that the hydrolysis of miscanthus is easy to perform and has low viscosity. On the contrary, the higher porosity grade of wheat straw than miscanthus (73% against 52%) contributed to have a very high viscosity at 20% w/w DM. The development of a fed-batch strategy allowed the reduction of viscosity inducing the energetic consumption lowering from 30 kJ to 10 kJ. It has been also proven that the miscanthus addition in wheat straw achieved to decrease mixing energy consumption at 5-8 kJ, when it represented more than 30% of the total mass of the reaction medium.

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Mixing Time, Homogenization Energy and Residence Time Distribution in a Gas-Induced Contactor

Cited by 24 publications

References 19 publications

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Hydrodynamics and Mass Transfer Analysis in BioFlow® Bioreactor Systems

Enzymatic hydrolysis at high dry matter content: The influence of the substrates’ physical properties and of loading strategies on mixing and energetic consumption

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