Loading...
Search for:
hold-up
0.005 seconds
Slip velocity in pulsed disc and doughnut extraction columns
, Article Chemical Industry and Chemical Engineering Quarterly ; Volume 17, Issue 3 , 2011 , Pages 333-339 ; 14519372 (ISSN) ; Jalilvand, H ; Outokesh, M ; Sharif University of Technology
2011
Abstract
In the present work, slip velocity has been measured in a 76 mm diameter pulsed disc and doughnut extraction column for four different liquid-liquid systems. The effects of operating variables including pulsation intensity and dispersed and continuous phase flow rates on slip velocity have been investigated. The existence of three different operational regimes, namely mixersettler, transition, and emulsion regimes, was observed when the energy input was changed. Empirical correlations are derived for prediction of the slip velocity in terms of operating variables, physical properties of the liquid systems, and column geometry for different regimes. Good agreement between prediction and...
The influence of nanoparticles on hydrodynamic characteristics and mass transfer performance in a pulsed liquid-liquid extraction column
, Article Chemical Engineering and Processing: Process Intensification ; Volume 50, Issue 11-12 , 2011 , Pages 1198-1206 ; 02552701 (ISSN) ; Khoobi, N ; Mozdianfard, M. R ; Bahmanyar, H ; Sharif University of Technology
Abstract
With respect to the influence of nanoparticles on mass transfer characteristics, limited number of studies available in the literature, deal primarily with gas-liquid systems. In this work, mass transfer performance and hydrodynamic characteristics including static and dynamic dispersed phase hold-ups of nanofluids have been investigated for pulsed liquid-liquid extraction column (PLLEC). The nanofluids used were prepared by dispersing SiO2 nanoparticles of 0.01, 0.05 and 0.1 volume percent with two different hydrophobicities in kerosene as base fluid using ultrasonication. UV-vis spectrophotometer was also used for evaluation of the nanofluids stability. The results were compared with...
Simulation of Gas-Liquid Flow Patterns in Vertical, Horizontal and Inclined Pipes and Assessment of Empirical Models
, M.Sc. Thesis Sharif University of Technology ; Fatemi, Mobeen (Supervisor)
Abstract
Multiphase flows are commonly encountered in oil and gas industries. Flow fields in production operations are often complex and include multiphase flows of gas and liquid. The prediction of pressure gradients, liquid holdup and flow patterns occurring during the simultaneous flow of gas and liquid in pipes and wellbores is necessary in designing production facilities. Previously, due to their complex nature, these flow patterns have been mostly investigated only experimentally and empirical correlations based on the experimental data. From another point of view, it is almost impossible to experimentally realize all the flowing conditions for each of the flowing patterns. Nowadays, computer...
Dispersed phase holdup in a pulsed disc and doughnut extraction column
, Article Brazilian Journal of Chemical Engineering ; Volume 28, Issue 2 , June , 2011 , Pages 313-323 ; 01046632 (ISSN) ; Jalilvand, H ; Outokesh, M ; Sharif University of Technology
2011
Abstract
Dispersed phase holdup has been measured in a 76 mm diameter pulsed disc and doughnut extraction column for three different liquid-liquid systems. The effects of operational variables such as pulsation intensity and dispersed and continuous phase flow rates on holdup have been investigated and found to be significant. The existence of three different operational regimes, namely mixer-settler, dispersion, and emulsion regimes, was observed when the energy input was changed. The results indicated that the characteristic velocity approach is applicable to this type of extraction column for analysis of holdup in the transition and emulsion regions. Empirical correlations are derived for...
Investigation of the impact of synthesized hydrophobic magnetite nanoparticles on mass transfer and hydrodynamics of stagnant and stirred liquid–liquid extraction systems
, Article Chemical Engineering Research and Design ; Volume 147 , 2019 , Pages 305-318 ; 02638762 (ISSN) ; Azizi, Z ; Bastani, D ; Sharif University of Technology
Institution of Chemical Engineers
2019
Abstract
The impact of modified magnetite nanoparticles (MMNPs)on hydrodynamics and mass transfer in liquid–liquid extraction process was assessed using a ternary chemical system of toluene-acetic acid–water. The organic phase which contained toluene and acetic acid was dispersed through water, and the mass transfer of acetic acid between two phases was investigated. The hydrophobic modified magnetite nanoparticles (MMNPs)prepared through an optimized in-situ method were added to the dispersed phase at different concentrations (0.001−0.005 wt%). Two separate conditions were provided in the experiments, i.e. stagnant and stirred continuous phase. The latter case was provided by a rotor at two...
Experimental modeling and uncertainty analysis of dispersed phase holdup at flooding in a pulsed disc-doughnut column, case study: Response surface methodology and Monte-Carlo simulation
, Article Progress in Nuclear Energy ; Volume 141 , 2021 ; 01491970 (ISSN) ; Ghaemi, A ; Hemmati, A ; Asadollahzadeh, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study aims to investigate, optimize, and simulate the dispersed phase holdup at flooding conditions for the standard physical systems in a pulsed extraction column with the disc-doughnut configuration. The interaction impacts for operational parameters (pulse intensity and organic and aqueous phase velocities) and interfacial tension (systems type) were examined using the response surface approach. A novel correlation for the dependent parameter, namely holdup at flooding based on the quadratic model, was developed with the central composition design methodology. A desirable agreement between actual data and calculated data from the proposed model was observed because of the high...
The performance of pulsed scale-up column for permeable of selenium and tellurium ions to organic phase, case study: Disc and doughnut structure
, Article Chemical Engineering and Processing - Process Intensification ; Volume 157 , 2020 ; Torkaman, R ; Torab Mostaedi, M ; Asadollahzadeh, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
A research investigation of the overall mass transfer coefficients, holdup and mean drops of dispersed phase as well as slip and characteristic velocities were carried out in the pulsed scale-up column with disc and doughnut structure for extraction of tellurium and selenium from a hydrochloric acid medium with TBP extractant. The impact of operating conditions containing the pulse intensity, inlet aqueous and solvent phase velocities have been studied on the mass transfer rates, and the special column characteristic. By considering the reactive extraction situations, modified models were derived for predicting of holdup, d32, and slip velocity in this extractor. The axial diffusion model...
Exact hydrodynamic description of pilot plant Oldshue-Rushton contactor: a case study with the introduction of selenium and tellurium into reaction system
, Article International Journal of Environmental Analytical Chemistry ; 2020 ; Torkaman, R ; Torab Mostaedi, M ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
In this paper, the hydrodynamic behaviour of the chemical reaction system (selenium, tellurium, and TBP) was interpreted in the Oldshue-Rushton extraction column. The optimum operating parameters for extracting the selenium and tellurium from chloride medium were carried out by using the batch experiments. The feed acidity of 5 molar and solvent phase with 20% (v/v) TBP in kerosene were optimised to examine the hydrodynamic parameters of the mentioned column. The impacts of operating variables such as rotor speed, inlet aqueous phase velocity, and inlet solvent phase velocity on the dispersed phase hold-up, mean drop size, slip velocity, drop size distribution, and extraction rate were...