scholarly journals Effect of channel size on mass transfer during liquid–liquid plug flow in small scale extractors

2015 ◽  
Vol 262 ◽  
pp. 785-793 ◽  
Author(s):  
Dimitrios Tsaoulidis ◽  
Panagiota Angeli
Keyword(s):  
Mass Transfer ◽  
Plug Flow ◽  
Small Scale ◽  
Channel Size ◽  
Liquid Plug

scholarly journals Simulation and Analysis of Plug Flow Fluidized Bed Dryer

2020 ◽  
Vol 9 (7) ◽  
pp. 805-811
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Plug Flow ◽  
Small Scale ◽  
Outlet Temperature ◽  
Drying Process ◽  
Fluidized Bed Dryer ◽  
Hot Air

Today many industries now use the dryer as a part of grain-drying process even during wet and dry seasons. This helps in reducing spoilage and wastage of paddy. Mostly the available industrial dryers are expensive to purchase and to maintain its smooth functioning. This study therefore is a step to design a simple Plug flow fluidized dryer that can lead to introduce small scale dryers to paddy process industry. The Plug flow fluidized bed dryers are designed and fabricated in this study consists of the drying chamber, hot air distributer plate, hot air inlet and exit system, paddy entry and exit system, fluidization chamber unit with temperature control unit and the centrifugal fan. The evaluation of dryer is based on drying time and reduction in moisture content and outlet temperature of paddy on quality parameters. Dryer dimensions are very important to analyze heat and mass transfer analysis of the Plug flow fluidized bed drying process of paddy grains. It was found d that heat and mass transfer properties of paddy grains in fluidized bed dryer was decreases as the time of drying passes and very rapid at the start of drying. The model present here predicts about dryer dimensions along safe zone of rough rice moisture content with other parameters. Simulation results show a good agreement between the simulation model and the existing simulation models

Extraction of {UO2}2+ in Intensified Separators of Different Sizes Using Ionic Liquids

2016 ◽  
Author(s):  
Dimitrios Tsaoulidis ◽  
Eduardo Garciadiego Ortega ◽  
Panagiota Angeli
Keyword(s):  
Mass Transfer ◽  
High Speed ◽  
Extraction Efficiency ◽  
Liquid Mixtures ◽  
Small Scale ◽  
Acid Solutions ◽  
Transfer Coefficients ◽  
High Speed Imaging ◽  
Channel Size ◽  
Aqueous Nitric Acid

In this work the extraction of dioxouranium(VI) from aqueous nitric acid solutions (3M) into TBP/ionic liquid mixtures (30% v/v), is studied in intensified small scale separator channels of different sizes. High speed imaging is used to obtain the important hydrodynamic features of the flow (i.e. plug velocity and plug length) which are related to mass transfer and extraction efficiency. It was found that the overall mass transfer coefficients varied between 0.07 and 0.24 s−1 and increase by decreasing the channel size. The extraction efficiency was also affected by the channel size. A decrease in channel size leads to higher extraction efficiencies, while for a certain channel size the extraction efficiency decreases by increasing the mixture velocity.

scholarly journals Effect of channel size on liquid-liquid plug flow in small channels

AIChE Journal ◽  
2015 ◽  
Vol 62 (1) ◽  
pp. 315-324 ◽  
Author(s):  
Dimitrios Tsaoulidis ◽  
Panagiota Angeli
Keyword(s):  
Plug Flow ◽  
Channel Size ◽  
Liquid Plug ◽  
Small Channels

scholarly journals Scale-Up Studies for Co/Ni Separations in Intensified Reactors

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1106
Author(s):  
Dimitrios Tsaoulidis ◽  
Milan Mamtora ◽  
Marta Mayals Gañet ◽  
Eduardo Garciadiego-Ortega ◽  
Panagiota Angeli
Keyword(s):  
Mass Transfer ◽  
Scale Up ◽  
Plug Flow ◽  
Impinging Jets ◽  
Small Scale ◽  
Residence Times ◽  
Transfer Coefficients ◽  
Channel Diameter ◽  
Mass Transfer Coefficients ◽  
Cyanex 272

In this paper, the effect of the scalability of small-scale devices on the separation of Co(II) from a binary Co(II)/Ni(II) mixture in a nitric acid solution by an organic Cyanex 272/TBP/kerosene (Exxsol D80) phase is studied. In particular, circular channels with diameters of 1, 2, and 3.2 mm are considered. The results were compared against those from a confined impinging-jets (CIJ) cell with a main channel diameter of 3.2 mm. The effects of total flowrate, residence time, Cyanex 272 concentration, and flowrate ratio on the mass transfer performance were investigated. It was found that at increased channel size, the throughputs were also increased but the extraction percentages remained the same. Higher extraction percentages were obtained by using the CIJ configuration at short residence times. However, for longer residence times, the mass transfer coefficients were similar and capillary channels should be preferred over the CIJ because of the ease of separation of the two phases at the end of the unit. The overall mass transfer coefficients ranged between 0.02 and 0.14 s−1 for the capillary channels during plug flow and between 0.05 and 0.45 s−1 for the CIJ cells during dispersed flow.

Kinetics, mass transfer, and mass re-equilibrium for arsenate adsorption on iron oxide-based carbons

2018 ◽  
Author(s):  
◽  
Zhengyang Wang
Keyword(s):  
Mass Transfer ◽  
Water Treatment ◽  
Large Scale ◽  
Freundlich Isotherm ◽  
Small Scale ◽  
Crossover Point ◽  
Hydraulic Residence Time ◽  
In Situ Extraction ◽  
Small Water ◽  
Batch Tests

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Removal of arsenic (As) from drinking water sources is much needed worldwide, and small water treatment systems, such as point-of-use (POU) treatment, could be an effective solution for residential applications. Adopting existing removal technologies that are successful in large-scale treatment to small-scale units, however, is rather ineffective due to the short hydraulic residence time in small water treatment systems. … The Freundlich isotherm can fit experimental data well: a crossover point for the two fitted Freundlich isotherms was observed and nano-FeAC had higher adsorption plateau. Furthermore, we demonstrated that due to the MRE process, a pseudo-equilibrium of FeMC was altered to another steady state by an in situ extraction with nano-FeAC in both batch and column systems. The overall inter-medium mass transfer resulted in both improved adsorption densities obtained by batch tests and a large bed volume prior to the 10 [mu]g As/L breakthrough at a short empty bed contact time (0.85 min).

Multiscale Issues in DNS of Multiphase Flows

2011 ◽  
Author(s):  
Bahman Aboulhasanzadeh ◽  
Siju Thomas ◽  
Jiacai Lu ◽  
Gretar Tryggvason
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Multiphase Flows ◽  
Analytical Models ◽  
Small Scale ◽  
Layer Model ◽  
Inertia Effects ◽  
Thin Film Model ◽  
Simple Boundary ◽  
Separation Of Scales

In direct numerical simulations (DNS) of multiphase flows it is frequently found that features much smaller than the “dominant” flow scales emerge. Those features consist of thin films, filaments, drops, and boundary layers, and usually surface tension is strong so the geometry is simple. Inertia effects are also small so the flow is simple and often there is a clear separation of scales between those features and the rest of the flow. Thus it is often possible to describe the evolution of this flow by analytical models. Here we discuss two examples of the use of analytical models to account for small-scale features in DNS of multiphase flows. For the flow in the film beneath a drop sliding down a sloping wall we capture the evolution of films that are too thin to be accurately resolved using a grid that is sufficient for the rest of the flow by a thin film model. The other example is the mass transfer from a gas bubbly rising in a liquid. Since diffusion of mass is much slower than the diffusion of momentum, the mass transfer boundary layer is very thin and can be captured by a simple boundary layer model.

Recycling and Extraction of Zinc Ions in Disc-Donut Column Considering Forward Mixing Mass Transfer, Chemical Reaction and Effects of Pulsed and non-Pulsed Condition

2021 ◽  
Author(s):  
Mehdi Asadollahzadeh ◽  
Rezvan Torkaman ◽  
Meisam Torab-Mostaedi ◽  
Mojtaba Saremi
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Flow Rate ◽  
Positive Impact ◽  
Plug Flow ◽  
Model Parameters ◽  
Zinc Ions ◽  
Zinc Extraction ◽  
Balance Equations ◽  
Transfer Rates

Abstract The current study focuses on the recovery of zinc ions by solvent extraction in the pulsed contactor. The Zn(II) ions from chloride solution were extracted into the organic phase containing D2EHPA extractant. The resulting data were characterized for the relative amount of (a) pulsed and no-pulsed condition; and (b) flow rate of both phases. Based on the mass balance equations for the column performance description, numerical computations of mass transfer in a disc-donut column were conducted and validated the experimental data for zinc extraction. Four different models, such as plug flow, backflow, axial dispersion, and forward mixing were evaluated in this study. The results showed that the intensification of the process with the pulsed condition increased and achieved higher mass transfer rates. The forward mixing model findings based on the curve fitting approach validated well with the experimental data. The results showed that an increase in pulsation intensity, as well as the phase flow rates, have a positive impact on the performance of the extractor, whereas the enhancement of flow rate led to the reduction of the described model parameters for adverse phase.

scholarly journals Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

2020 ◽  
Vol 10 (23) ◽  
pp. 7842-7856 ◽  
Author(s):  
B. Venezia ◽  
E. Cao ◽  
S. K. Matam ◽  
C. Waldron ◽  
G. Cibin ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Plug Flow ◽  
Catalytic Reactions ◽  
Dead Volume ◽  
Heterogeneous Catalytic ◽  
Spatially Resolved ◽  
Operando Xas

A novel microreactor for operando XAS and DRIFTS studies of catalytic reactions is reported, exhibiting plug-flow, isothermal behaviour and absence of mass transfer resistances and dead volume, enabling time- and spatially-resolved experiments.

scholarly journals Using modeling to select catalyst dilution methods for mass transfer intensification in lab gas–liquid fixed-bed reactors

2020 ◽  
Vol 75 ◽  
pp. 74
Author(s):  
Alberto Servia
Keyword(s):  
Mass Transfer ◽  
Heterogeneous Catalyst ◽  
Fixed Bed ◽  
Small Scale ◽  
Inert Material ◽  
Benzene Hydrogenation ◽  
Liquid Mass ◽  
Fixed Bed Reactors ◽  
Heat Effects ◽  
Liquid Mass Transfer

Heterogeneous catalyst testing methodology at the lab scale must provide intrinsic kinetics data for reactor design purposes as well as the intrinsic activity ranking during catalyst screening in the field of refining and petrochemistry. The significant downscaling of the past century coupled with the increasingly active catalytic formulations may introduce considerable momentum, mass and heat effects in experiments at small scale. Catalyst dilution has emerged as one versatile and robust way to reduce the impact of momentum and heat effects on heterogeneous catalyst testing. This paper presents a methodology based on global phenomena and catalyst dilution modeling to assess and optimize reactor loading techniques for specific problems. More particularly, the aim is to provide catalysts developers and kinetics experts with concrete guidelines for intensifying gas-liquid mass transfer in lab gas–liquid fixed-bed reactors through catalyst dilution. The methodology is applied to the kinetics determination of the oil residue Hydrodemetallation (HDM) and to the screening of catalysts for benzene hydrogenation. Layered dilution, consisting on the split of the catalyst in two beds separated by an intermediate bed containing an inert material of the same size as the catalyst, poorly improves gas–liquid mass transfer. Uniform dilution, based on the direct mixture of catalyst and inert material of the same size, significantly enhances gas–liquid mass transfer as the reactant local consumption per reactor unit volume is strongly reduced. Combinations of both abovementioned dilution techniques can be used with fast and/or high stoichiometric factor chemical systems operated at conversions higher than 70%. A new criterion is proposed to calculate the minimum dilution factor to guarantee negligible gas–liquid mass transfer limitations as a function of conversion, external mass transfer and global pseudo second-order kinetics.

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