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membrane-contactor
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Gas-liquid membrane contactors: Modeling study of non-uniform membrane wetting
, Article Journal of Membrane Science ; Volume 555 , 2018 , Pages 463-472 ; 03767388 (ISSN) ; Mousavi, S. A ; Bozarjomehri, R. B ; Bakhtiari, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Current available models for simulation of the separation process in gas-liquid membrane contactor (MC) systems consider a uniform partial membrane wetting along the membrane length (Lmem). However, transmembrane pressure changes along the Lmem. Additionally, the available models usually consider a simplified uniform pore size to represent the micro-porous MC. Additionally, not all pores in a MC have the same size. In this study, a pore-scale network model is developed to simulate the physical separation of H2S using MCs by taking to account for (i) transmembrane pressure variation and (ii) pore size distribution of MC. The model results are compared with the experimental results of H2S...
Modeling and Simulation of Hollow Fiber Membrane Contactor in Presence of Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor) ; Safekordi, Ali Akbar (Supervisor)
Abstract
In this study, a comprehensive 2D mathematical model has been developed for the simulation of physical and chemical absorption of carbon dioxide in hollow fiber membrane contactors in the presence of nanoparticles. The model were developed by considering molecular diffusion in radial and axial directions as well as non-wetting conditions. Carbon dioxide absorption was simulated from a gas mixture containing carbon dioxide and air, that flows in the shell. Also, absorbent containing nanoparticles flows in tube side and counter currently. Effects of presence of nanoparticles were modeled by taking into account two prominent mechanisms proposed in the literature for mass transfer enhancement in...
Preparation of Membrane Contactor for H2S, CO2 and CH4 Separation
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Moosavi, Abbas (Supervisor)
Abstract
Recently separation technology has been developed and engineers are trying to find more rapid and more economic ways in order to reach pure materials. One of the most important needs of human being is natural gas which has some impurities. Acid gases such as carbon dioxide and hydrogen sulfide must be separated from methane. This operation is called gas sweetening. Membrane contactors are equipments recently developed and may be used instead of packed towers for gas sweetening in the future. In this project we designed and made a membrane contacting unit to separate carbon dioxide and hydrogen sulfide from methane. This unit lets you to study the effect of many parameters such as gas and...
, M.Sc. Thesis Sharif University of Technology ; Mosavi, Abbas (Supervisor) ; Shojaei, Akbar (Co-Advisor)
Abstract
In this work nanocomposite CNT/polysulfone and CNT/polyethersulfone membranes for membrane contactor application in gas separation were fabricated. The two types of CNTs used for chemical and physical separation of H2S from a mixture of CH4 an H2S, had the outer diameter of 20-30nm and 50-100nm. One of the greatest concerns about using membrane contactors for gas separation applications is the wetting of membranes which consequently leads to decrease in separation performance. The aim of this study is to enhance the hydrophobicity of membranes by mixing hydrophobic carbon nanotubes in the polymeric matrix. The effect of factors like type of the polymer, diameter of the carbon nanotube and...
Gas absorption enhancement in hollow fiber membrane contactors using nanofluids: Modeling and simulation
, Article Chemical Engineering and Processing: Process Intensification ; Volume 119 , 2017 , Pages 7-15 ; 02552701 (ISSN) ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this article, a comprehensive 2D mathematical model has been developed to simulate process intensification of carbon dioxide absorption in the presence of nanoparticles in hollow fiber membrane contactors (HFMCs). The influences of nanoparticle were taken into account considering Brownian motion and Grazing effect as dominant phenomena of mass-transfer enhancement in nanofluids. The obtained simulation results were validated against experimental data reported in the literature and excellent agreement was obtained. It was found that by adding 0.05 wt % silica nanoparticles, the absorption rate could be enhanced by 16%, while the corresponding value is 32% for CNT nanoparticles. High...
Pore-scale Network Modeling of Gas-Liquid Membrane Contactors for CO2 and H2S Separation
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Abbas (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
Abstract
In this study, a tree-dimensional random pore-scale network model is used to simulate the membrane contactor porous medium. Drainage and imbibition phenomena is simulated to have a better knowledge of liquid and/gas intrusion trough the membrane porous structure. A genetic algorithm is used as an optimization tool. Several variables such as the number, radius and location of pores, the coordination number, as well as the radius and length of the throats are used herein as the optimization parameters. The difference between the binary SEM images and virtual sections on the generated network in conjunction with the permeability and mean pore size data were selected as the objective function....
Modeling and Simulation of Gas Absorption in Hollow Fiber Membrane Contactors Using Nanofluids
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Today, the usage of hollow membrane contactors is considered by the researchers as a novel solution in the separation and purification industry, including the sweetening of gas. Improving the performance of these devices requires a more detailed study of the process factors and changes in its chemistry. Hence, providing a suitable mathematical model by examining the details of the flow pattern within the contactor is based on the computational fluid dynamics technique in the agenda. Also, improving the absorption of components such as carbon dioxide and hydrogen sulfide from the gas mixture using chemical absorbents such as monoethanolamine will be investigated. The change in the mass...
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Seifkordi, Ali Akbar (Supervisor)
Abstract
Using membrane contactors for acid gas removal, combines the advantages of membrane based separation processes and traditional ones. In this project we aim to study the use of a membrane absorption system for sweetening gas streams containing mixed acid gases with composition similar to raw natural gas. H2S and CO2 exist in the gas stream simultaneously which can be removed by mixture of alkanolamine solvents, including MDEA, DEA and MEA, are used for treating. A lab-scale membrane absorption setup with feed capacity of 2 lit/min, was designed, constructed and commissioned. Several hollow fiber modules equipped with PSf and PVDF membranes were fabricated. Our results revealed that reaching...
Simultaneous separation of H2S and CO2 from natural gas by hollow fiber membrane contactor using mixture of alkanolamines
, Article Journal of Membrane Science ; Volume 377, Issue 1-2 , July , 2011 , Pages 191-197 ; 03767388 (ISSN) ; Soltanieh, M ; Mousavi, S. A ; Sharif University of Technology
2011
Abstract
In the present work we studied the use of a membrane contactor system for simultaneous absorption of H2S and CO2 from a gas mixture similar to natural gas. MDEA solution and mixtures of MDEA/DEA and MDEA/MEA were used as absorbent liquid. PVDF and PSf hollow fiber membranes were used in the membrane contactor modules. Design of experiments were carried out by Taguchi method in a manner that a systematical investigation of the effect of operational parameters (temperature, pressure, gas and liquid flow rates, absorbent concentration and acid gas content of the feed), in addition to the effect of membrane material and absorbent liquid, was implemented on process performance parameters...
Gas-liquid membrane contactors: effects of polymer concentration and solvent type on pore size distribution
, Article Journal of Membrane Science ; Volume 563 , 2018 , Pages 813-819 ; 03767388 (ISSN) ; Mousavi, S. A ; Bozorgmehri Bozarjomehri, R ; Bakhtiari, F ; Sharif University of Technology
Abstract
This study investigates the effects of polymer concentration and solvent type on the pore size distribution (PSD) of the fabricated gas-liquid membrane contactors (MCs). Eighteen flat-sheet MCs are fabricated using polysulfone (PSf) and polyethersulfone (PES) polymers, with polymer concentration of 10%, 15%, and 20%. Dimethylformamide (DMF) and n-methyl-2-pyrrolidone (NMP) solvents are used to prepare the polymeric solutions. The role of polyvinylpyrrolidone (PVP) on the mean pore size of MCs is also studied. Scanning electron microscope (SEM) analysis is applied to visualize the pore system of the fabricated MCs. Image processing technique is used to obtain the PSD of the fabricated MCs...
Modeling of Membrane Contactors For Separation of Multi-Component Gases by Mixtures of Solvents
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
In the present work a comprehensive mathematical model has been developed for CFD simulation of transport phenomena in the hollow fiber membrane contactors. The system which has been studied was a gas sweetening including methane, carbon dioxide, and hydrogen sulfide in the gas phase and MEA aqueous solution as the solvent. Effects of temperature distribution on the contactor efficiency predicted taking into account the heat of solution, the heat of reaction, and the viscous dissipation. Major focus of the present study was on dynamic behavior of the contactor considering the entrance regions of momentum, energy, and mass transfers. CFD methods have been developed to solve the nonlinear...
CFD modeling of CO2 absorption in membrane contactors using aqueous solutions of monoethanolamine-ionic liquids
, Article Industrial and Engineering Chemistry Research ; Volume 59, Issue 41 , 2020 , Pages 18629-18639 ; Darabi, M ; Ghaleh, V. R ; Bakhtiari, O ; Sharif University of Technology
American Chemical Society
2020
Abstract
The effects of addition of an ionic liquid to pure water as a physical absorbent and monoethanolamine (MEA) solutions as a chemical absorbent on carbon dioxide (CO2) absorption through hollow fiber membrane contactors were investigated using a 2D axisymmetric model. A numerical simulation was developed based on finite element method using computational fluid dynamics techniques. Liquid phase flowed in the tube side and gas mixture containing CO2 passed in the shell side of the membrane contactor in co-current and countercurrent modes. The simulation results are consistent with experimental data, and the root-mean-square error was calculated as 9 and 13% for pure water and 25 wt % for ionic...