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mass-transfer-coefficients
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Solid-Liquid Mass Transfer in the Annular Region of a Taylor-Couette Contacting Device
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Vortex flow reactor (VFR) is used for biochemical reactions and separation applications. By using the second flow regime, called Taylor-Couette flow, VFR provides high amounts of mass transfer and mixing for biological components sensitive to shear stress. Mass transfer in a bench-scale Taylor-Couette contactor with a radius ratio, equal to 0.77 and an aspect ratio, equal to 30.7 was studied for solid particles dissolution. The working fluid was water and the suspended particles were benzoic acid. In this project the concentration of fluid phase was measured by injection of definite amount of the solid particles in to the contactor and sampling in different time intervals and the effects of...
Estimation of mass transfer during drop formation: New flow expansion model
, Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; 2004 , Pages 27-34 ; 0791847179 (ISBN); 9780791847176 (ISBN) ; Bastani, D ; Sharif University of Technology
American Society of Mechanical Engineers
2004
Abstract
Although there is extensive experimental, theoretical and numerical research on dynamics of drop formation in liquid-liquid systems, the evaluation of mass transfer during drop formation is rather complex and there has been little research on that. The various mathematical models developed for this problem are generally based on a solution of the diffusion equation without any allowance for circulation within the drop. This is the main reason for the poor prediction of these models in many cases for which internal convection has an important effect on mass transfer rate. In this paper an attempt was made to define a parameter related to the extent of the convective mixing within the growing...
Experimental study and correlation for mass transfer coefficient in the pilot plant multistage column with the presence of molybdenum
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 41, Issue 2 , 2022 , Pages 544-554 ; 10219986 (ISSN) ; Torab Mostaedi, M ; Outokesh, M ; Torkaman, R ; Asadollahzadeh, M ; Sharif University of Technology
Iranian Institute of Research and Development in Chemical Industries
2022
Abstract
In the present work, multistage extraction column performance for reactive separation of molybdenum from the leach aqueous phase by using D2EHPA and TBP in kerosene was investigated by using the axial diffusion model. The variation of volumetric overall mass transfer coefficients based on continuous phases at various operating conditions was obtained. By considering the chemical reaction conditions, the experimental data indicate that the volumetric overall mass transfer coefficients increase with an enhancement in rotor speed and continuous and dispersed phase flow rates. According to the sensitivity analysis, the rotor speed and flow rate of the dispersed phase have more influence on...
Prediction of the Contribution of Mass Transfer During Jet Formation in Liquid-Liquid Extraction Columns
, M.Sc. Thesis Sharif University of Technology ; Sayf Kordi, Ali Akbar (Supervisor)
Abstract
There are many different opinions about the mass transfer contribution during jet formation in liquid - liquid extraction columns, and this could impact on their design. In this work, using experimental data obtained in two RDC columns and unpublished data of the jet mass transfer coefficients, mass transfer can be predicted during jet formation. The jet length and diameter were anticipated by using existing relations, and then the jet mass transfer coefficient was predicted, jet mass transfer rate and total column mass transfer rate were calculated and finally the contribution of mass transfer during jet formation in the column was predicted. Mass transfer contribution in the jet in various...
Investigation of mass transfer coefficient under jetting conditions in a liquid-liquid extraction system
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 1 , 2010 , Pages 1-12 ; 10219986 (ISSN) ; Omidkhah, M. R ; Bastani, D ; Saifkordi, A. A ; Sharif University of Technology
Abstract
In this research mass transfer coefficient under jetting regime in different directions (from dispersed to continuous and continuous to dispersed phase) has been studied using an experimental setup. n-Butanol-succinic acid-water with low interfacial tension has been selected as experimental chemical system. The effects of various parameters such as jet velocity, nozzle diameter and the height of the continuous phase above the nozzle, on mass transfer coefficient have been investigated. A correlation has also been derived in order to predict the mass transfer coefficient as a function of physical properties of both phases and aforementioned parameters. Based on the experimental results, mass...
Study of the effect of fluid flow on corrosion rate for simple carbon steel in aqueous solution using rotating disk electrode
, Article 18th International Congress of Chemical and Process Engineering, CHISA 2008, Prague, 24 August 2008 through 28 August 2008 ; 2008 ; Mohagheghi, A ; Sharif University of Technology
2008
Abstract
The influence of fluid flow on the corrosion of simple carbon steel ST37 (AISI 1020) in aqueous solution of Bandar-Abbas gas well was studied at 25°C under air-saturated condition. The mechanism and kinetic of corrosion in different hydrodynamic conditions were determined using a rotating disk electrode. Increasing the velocity of rotating disk ≤ 1000 rpm caused an augmentation in corrosion rate from 9.89 to 18.95 mill in./yr. Increasing the velocity beyond 1000 rpm changed the corrosion mechanism so that the activation polarization will control the corrosion process, and the variation in corrosion rates was due to various corrosion mechanisms rather than mass transfer of reactant component....
Investigation on reactive flow through porous media by quadtree Lattice Boltzmann
, Article Journal of Natural Gas Science and Engineering ; Volume 104 , 2022 ; 18755100 (ISSN) ; Ayatollahi, S ; Jamshidi, S ; Raoof, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this study, in order to investigate the effect of the underlying pore-scale processes on continuum scale simulations of porous media dissolution, we improve the standard Lattice Boltzmann method using Quadtree grid refinement approach to simulate fluid flow and reactive transport through large domain sizes. Our results have shown considerable computational improvements up to 80% in simulation time together with increased numerical accuracy. The results and the added value of the new approach are discussed using comparison of our model with the conventional LBM. Moreover, we have applied a systematic analysis by increasing complexity levels and starting from fluid flow and continuing with...
Mass Transfer Modeling while Formation of Liquid Jet to another Liquid
, M.Sc. Thesis Sharif University of Technology ; Bastani, Darioush (Supervisor)
Abstract
Liquid-liquid extraction is one of most important processes in chemical industries. So determination of operating condition effects is very critical. In this thesis we modeled concentration profile in the jet via mathematical equations and compare with experimental data. The major problem in concentration profile and solving equations is lack of knowledge in velocity profile within the jet was formed. Therefore, different flow models such as piston flow model, parabolic flow model, vortex flow model and a cone flow model was used and terminal concentrations inside the jet compared with laboratory values. Results shows the most accurate model to predict the flow concentration along the...
Experimental and CFD Study of Physical Properties Effect on Hydrodynamic and Mass Transfer Coefficient of Single Drops
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor)
Abstract
In present study, it is tried to investigate the effect of physical properties on hydrodynamic and overall mass transfer coefficient of single drops using different experiments and then simulation of drop motion with OpenFOAM software version 1.7.1. the systems were choosen are toluene/acetone/water and n-butanol/succinic acid/water which their interfacial tensions are 36 and 1.6 mN/m respectively. Various type of nozzles have been used for produce of 1.5, 2, 3 and 4 millimeter drops. The results show that in absence of solute component, the rising velocity of toluene drops in each size is higher than rising velocity of butanol drops inside the water between 25 to 75 percent. But with...
Multi-Scale Lattice Boltzmann Simulation of Carbonate Rock Dissolution in Acidizing Process
, Ph.D. Dissertation Sharif University of Technology ; Ayatollahi, Shahabodin (Supervisor) ; Jamshidi, Saeed (Supervisor) ; Raoof, Amir (Co-Supervisor)
Abstract
During the Acidizing process in oil and gas reservoirs, the injected acid reacts with the rock grains, changes the rock pore structure and affects the flow conditions. Due to the presence of a large concentration gradient at the vicinity of the rock grains and the continuous changes in rock-fluid interfaces of the porous medium, the continuum assumption has been remained debatable for the effective local mass transport and effective molecular diffusion coefficients and the porosity-permeability relation in the continuum scale modeling of this process. Therefore, the need for pore scale modelling is evident. The novelty of this study relies in adapting the grid refinement method on the...
A new method to calculate efficiency of randomly-packed distillation columns and its comparison with the methods utilized in ASPEN Plus
, Article Fuel Processing Technology ; Volume 96 , 2012 , Pages 65-73 ; 03783820 (ISSN) ; Sadeghifar, A ; Sharif University of Technology
2012
Abstract
In this paper, a unique and applicable method was developed for calculation of efficiency (and mass and heat transfer coefficients) of randomly-packed distillation columns. This method has potential advantages; e.g., unlike all the available methods, it can calculate efficiency without using any empirical mass transfer and hydraulic correlations, and without the need to estimate the operational and hydraulic parameters of an operating column. It, therefore, will be free of errors and limitations of such empirical items and can be used for efficiency calculation of any random packing including new ones. Along with an analysis of the proposed method, the paper also presents a thorough analysis...
Model for excess mass-transfer resistance of contaminated liquid-liquid systems
, Article Industrial and Engineering Chemistry Research ; Volume 46, Issue 5 , 2007 , Pages 1563-1571 ; 08885885 (ISSN) ; Ghasemian, S ; Bastani, D ; Ahmadpour, N ; Sharif University of Technology
2007
Abstract
The prediction of mass-transfer rates into and from moving drops in the liquid-liquid systems has usually used the well-known Whitman two-film theory approach. According to the latter, the total resistance to mass transfer resides on each side of the interface and is described by the individual film mass-transfer coefficients for the continuous and dispersed phases in the absence of surface-active agents (contaminants). In the present work, the same approach has been used to model the excess mass-transfer resistance exerted by surface-active agents in the continuous phase. To achieve this goal, an experimental investigation has been conducted on the mass transfer into and from single drops...
Mass-transfer enhancement in single drop extraction in the presence of magnetic nanoparticles and magnetic field
, Article AIChE Journal ; Volume 62, Issue 12 , 2016 , Pages 4466-4479 ; 00011541 (ISSN) ; Molaei Dehkordi, A ; Fadaei, F ; Sharif University of Technology
John Wiley and Sons Inc
2016
Abstract
Magnetite nanoparticles with an average particle size of 28.8 nm were synthesized, coated with oleic acid, and characterized using various techniques such as DLS, FT-IR, SEM, XRD, VSM, and UV-Vis analysis. A nanofluid consisting of synthesized nanoparticles and 5 wt % acetic acid in toluene as the dispersed phase was prepared and used in the chemical test system, Toluene-Acetic Acid-Water, for the single drop extraction in the presence and absence of an external oscillating magnetic field. Influences of various operating and design parameters such as nanoparticle concentration, drop diameter, and the applied current and frequency on the overall mass-transfer coefficients for the...
Infrared thin layer drying of saffron (Crocus sativus L.) stigmas: Mass transfer parameters and quality assessment
, Article Chinese Journal of Chemical Engineering ; 2016 ; 10049541 (ISSN) ; Ghanbarian, D ; Maghsoodi, V ; Moheb, A ; Sharif University of Technology
Chemical Industry Press
Abstract
Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures (60, 70, ..., 110°C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were...
Infrared thin layer drying of saffron (Crocus sativus L.) stigmas: Mass transfer parameters and quality assessment
, Article Chinese Journal of Chemical Engineering ; Volume 25, Issue 4 , 2017 , Pages 426-432 ; 10049541 (ISSN) ; Ghanbarian, D ; Maghsoodi, V ; Moheb, A ; Sharif University of Technology
Chemical Industry Press
2017
Abstract
Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures (60, 70, …, 110 °C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were...
Reactive absorption in packed bed columns in the presence of magnetic nanoparticles and magnetic field: Modeling and simulation
, Article Journal of Industrial and Engineering Chemistry ; Volume 45 , 2017 , Pages 131-144 ; 1226086X (ISSN) ; Molaei Dehkordi, A ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry
2017
Abstract
In this article, the influences of ferrofluid and magnetic field on the reactive absorption in packed-bed contactors have been investigated. Because of importance of carbon dioxide emission as a global concern, absorption of carbon dioxide was chosen to investigate these effects. In this regard, multitube approach was applied to model the contactor. The simulation results were validated against experimental data reported in the literature in the absence of nanoparticles and magnetic field and good agreement was obtained. Moreover, influences of various operating conditions on the contactor performance were investigated. It was found that for 3.4 vol.% of magnetic nanoparticles (MNPs), the...
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...
Investigation of Drop Phase Mass Transfer Coefficient During Rising Drops in a Pulse Sieved Plate Column in Presence of Nano Particles
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor) ; Bahmanyar, Hossein (Supervisor)
Abstract
Nanofluids are new engineering materials with great potential for application in process industries. Their enhanced heat-transfer properties are reported in recent literatures. However, 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 droplet behavior along a pulsed liquid-liquid extraction column, is studied where SiO2 nanoparticles with concentrations of 0.01, 0.05 and 0.1 vol% and different hydrophobicities are applied to the dispersed phase. Using ultrasonication, nanoparticles were dispersed in kerosene as the base...
Experimental Investigation of Mass Transfer Coefficient and Specific Interfacial Area in a New TIJR in the Presence of Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
The theory of mass transfer accompanied by chemical reaction for gas-liquid systems was used to measure the specific interfacial area and mass transfer coefficient in a two impinging jets reactor (TIJR) in the presence of γ-Al_2 O_3 nanoparticles.The absorption of oxygen in sulfite solutions used for the determination of mass transfer characteristics. First 3 liters of nanofluids were prepared at concentration of 1 w% then diluted To produce 10 Liters of nanofluids containing 0.3 w%. The stability of this nanofluid was determined using uv-vis to be less more than 95% in the first 3 hours. The influence of weight percent of nanoparticles (0, 0.05, 0.1, 0.15, 0.2, 0.3) on the specific...
Optimization of Aeration & Dissolved Oxygen Concentration in Moving Bed Bio Reactors
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
In this research the performance of the Moving Bed Biofilm Rector (MBBR) in different amounts of dissolved oxygen (DO) was investigated. Reactor with a useful volume of 15 liters was used in this study. In order to obtain optimum oxygen concentration, stayed at 6, 10 and 15 hours, and at different levels of dissolved oxygen in the range 0.5 -6 mg/lit, the amount of organic material was removed respectively. Also, in two different aeration intensity of 3.5 and 5.5 liters per minute at different values of e% (percentage of filling of media) the mass transfer coefficient values were obtained. When the aeration intensity increases from 3.5 to 5.5 liters per minute, and the percentage of 40%...