Tracer experiments in fixed beds: effects of flow maldistribution on the estimation of transport kinetic parameters

Leitão, Anabela; Carlos, Philomene; Santos, Sandra; Rodrigues, Alírio E.

doi:10.1016/0923-0467(93)02800-c

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…Then, it is possible that, in this work, the expression of Chung and Wen provides an underestimation of the real effect of longitudinal dispersion. Unfortunately, also the applications of other expressions such as the one of Leitão et al [ 38 ] led to similar results (data not shown). According to such consideration, a linear regression starting from the axis origin was used to correlate the estimated data obtaining the relation reported in Equation (10), which showed an

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Section: Resultssupporting

confidence: 55%

Removal of Methylene Blue from Wastewater by Waste Roots from the Arsenic-Hyperaccumulator Pteris vittata: Fixed Bed Adsorption Kinetics

et al. 2023

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Phytoremediation of arsenic-contaminated water was successfully conducted by means of the perennial fern Pteris vittate, which is an arsenic-hyperaccumulator plant able to grow in hydroponic cultures. In order to avoid the costs linked to the disposal of As-contaminated biomass, in this work, Pteris vittata waste roots were tested as a low-cost bio-adsorbent for the removal of methylene blue (MB) from water in a fixed-bed adsorption configuration. As a matter of fact, methylene blue can negatively impact the growth and health of algae and plants by blocking light from reaching them in water, which can alter their normal biological processes. Previous works have already shown the potentiality of such material toward the uptake of methylene blue; however, all the studies conducted were just focused on batch-mode experiments. In this work, column runs were carried out at 20 °C, evaluating the bed void fraction for each test and hence estimating the apparent density of the material (300 g/L). The breakthrough curves collected were fitted by means of a mathematical model based on the linear driving force (LDF) approximation to obtain information on the mass transfer mechanism occurring in the system. A relation for the product between the LDF mass transfer coefficient and the solid specific surface (kLDFas) with respect to the Reynolds (Re) dimensionless number was obtained (kLDFas=0.45Re). The range of validity of such expression was Re<0.025. Its applicability was deeply discussed: in such conditions, the technology is ready to be tested at larger scales.

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.…”

Section: Resultssupporting

confidence: 55%

Removal of Methylene Blue from Wastewater by Waste Roots from the Arsenic-Hyperaccumulator Pteris vittata: Fixed Bed Adsorption Kinetics

et al. 2023

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“…In a first approach, the flow is assumed to be essentially one-dimensional and the dispersion generated by the flow along the wall is considered to be an increase of the overall axial dispersion. In this case, correlations are suggested to predict the overall axial dispersion [5][6][7][8]. In the second approach, the flow is considered to be two-dimensional.…”

Section: Introductionmentioning

confidence: 99%

Application of computational fluid dynamics to fixed bed adsorption calculations: Effect of hydrodynamics at laboratory and industrial scale

Augier

Laroche

Brehon

2008

Separation and Purification Technology

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“…The modeling of the adsorption process is complicated, as the flow and concentration distribution of the adsorbate is nonideal. Most of the research has been based on a one-dimensional − or two-dimensional dispersion model, , in which the adsorbate flow is either simplified or computed by using computational fluid dynamics (CFD), and the effect of uneven adsorbate concentration is represented by adding axial and radial dispersion terms with undetermined turbulent mass-transfer diffusivities D t,a and D t,r . The usual way to find the unknown diffusivity is either by employing empirical correlation obtained from inert tracer experiment or by guessing a Schmidt number applied to the whole process.…”

Section: Introductionmentioning

confidence: 99%

Rigorous Model for the Simulation of Gas Adsorption and Its Verification

Liu

et al. 2011

Ind. Eng. Chem. Res.

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A rigorous model containing conservation equations of momentum, energy, and mass, with their kÀε, t 2 Àε t , and newly developed c 2 Àε c closing formulations was proposed for simulating the gasÀsolid adsorption process. The feature of the proposed model is that the unknown turbulent mass-transfer diffusivity D t need not be estimated in advance. With this model, the breakthrough, regeneration, and temperature curves, as well as the D t , were simulated for the methylene chloride adsorption and regeneration processes. The simulated results were closely checked by the published data. It was found that the D t was unevenly distributed in the axial and radial directions, which means that the Schmidt number or Peclet number is varying throughout the adsorption column and cannot be simply represented by a constant or a simple formula. The simulated results on axial and radial concentration distributions along the column at different time are helpful to understand the process dynamics. The proposed model is especially useful for simulating the adsorption process where the turbulent mass-transfer diffusivity is unavailable.

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Tracer experiments in fixed beds: effects of flow maldistribution on the estimation of transport kinetic parameters

Cited by 5 publications

References 20 publications

Removal of Methylene Blue from Wastewater by Waste Roots from the Arsenic-Hyperaccumulator Pteris vittata: Fixed Bed Adsorption Kinetics

Removal of Methylene Blue from Wastewater by Waste Roots from the Arsenic-Hyperaccumulator Pteris vittata: Fixed Bed Adsorption Kinetics

Application of computational fluid dynamics to fixed bed adsorption calculations: Effect of hydrodynamics at laboratory and industrial scale

Rigorous Model for the Simulation of Gas Adsorption and Its Verification

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