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Membrane Distillation (membrane + distillation)
Selected AbstractsL -Lysine Monohydrochloride Syrup Concentration using a Membrane Hybrid Process of Ultrafiltration and Vacuum Membrane DistillationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2008O. Bakhtiari Abstract The development of energy saving membrane separation processes is finding a unique position in process industries. One of the important areas where they are employed is the biotechnology industry. This industry has its own specifications and requirements, e.g., levels of diluteness, thermal, chemical and shear fragility. Membrane separation processes have the characteristics necessary to match these specifications and needs. In this research, the determination of the experimental concentration of L -Lysine monohydrochloride (L -lysine-HCl) syrup was investigated using ultrafiltration (UF) and vacuum membrane distillation (VMD) hybrid membrane processes. Four parameters that are known to have significant influence on the UF process were examined, i.e., pressure difference across the membrane, feed concentration of L -lysine-HCl, feed velocity on the membrane surface, and pH. For the VMD unit, pressure difference and pH were replaced with feed temperature and vacuum pressure on the permeate side of membrane. Each process was carried out separately and the results were used to design a bench-scale process. In order to save time and money, the Taguchi method of experimental design was employed. The effects of feed concentration, pressure difference across the membrane, feed velocity on the membrane surface, and pH on the target variable, i.e., the membrane flux, in the UF process were 39.93, 38.65, 9.36, and 9.59,%, respectively. For the VMD process, these values were 64.79, 22.16, 6.21, and 2.14,% for feed temperature, feed concentration, vacuum pressure on the permeate side, and feed velocity on the membrane surface, respectively. [source] A study on membrane distillation by a solar thermal-driven systemHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2007Tsung-Ching Chen Abstract Membrane distillation (MD) is a membrane separation process that has long been investigated in small scale laboratory studies and has the potential to become a viable tool for water desalination. MD is a separation process that combines simultaneous mass and heat transfer through a hydrophobic microporous membrane. A solar collector is used in direct contact membrane distillation (DCMD) to heat seawater as a temperature driving force in heat transfer to establish seawater desalting systems. The effect of the temperature difference makes the brine vaporize in the hot fluid side and condense in the cold fluid side. The optimal operating parameters on the pure water production rate will also be examined in this study. The purposes of this study are to develop the theoretical heat and mass transfer formulations, simulate heat transfer rate of solar collector with internal fins in membrane distillation, and investigate the mass-transfer efficiency improvement in membrane distillation with the brine flow rate, solar collector efficiency, and temperature difference between both sides of membrane as parameters. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(7): 417,428, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20172 [source] Effect of surface modifying macromolecules stoichiometric ratio on composite hydrophobic/hydrophilic membranes characteristics and performance in direct contact membrane distillationAICHE JOURNAL, Issue 12 2009M. Qtaishat Abstract The stoichiometric ratio for the synthesis components of hydrophobic new surface modifying macromolecules (nSMM) was altered systematically to produce three different types of nSMMs, which are called hereafter nSMM1, nSMM2, and nSMM3. The newly synthesized SMMs were characterized for fluorine content, average molecular weight, and glass transition temperature. The results showed that fluorine content decreased with increasing the ratio of ,,,-aminopropyl poly(dimethyl siloxane) to 4,4,-methylene bis(phenyl isocyanate). The synthesized nSMMs were blended into hydrophilic polyetherimide (PEI) host polymer to form porous hydrophobic/hydrophilic composite membranes by the phase inversion method. The prepared membranes were characterized by the contact angle measurement, X-ray photoelectron spectroscopy, gas permeation test, measurement of liquid entry pressure of water, and scanning electron microscopy. Finally, these membranes were tested for desalination by direct contact membrane distillation and the results were compared with those of commercial polytetraflouroethylene membrane. The effects of the nSMM type on the membrane morphology were identified, which enabled us to link the membrane morphology to the membrane performance. It was found that the nSMM2/PEI membrane yielded the best performance among the tested membranes. In particular, it should be emphasized that the above membrane was superior to the commercial one. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] A novel approach to fabricate macrovoid-free and highly permeable PVDF hollow fiber membranes for membrane distillationAICHE JOURNAL, Issue 3 2009Sina Bonyadi First page of article [source] Experimental Study and Design of a Submerged Membrane Distillation BioreactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2009J. Phattaranawik Abstract A hybrid process incorporating membrane distillation in a submerged membrane bioreactor operated at elevated temperature is developed and experimentally demonstrated in this article. Since organic particles are rejected by an ,evaporation' mechanism, the retention time of non-volatile soluble and small organics in the submerged membrane distillation bioreactor (MDBR) is independent of the hydraulic retention time (mainly water and volatiles). A high permeate quality can be obtained in the one-step compact process. The submerged MD modules were designed for both flat-sheet membranes and tubular membrane configurations. The process performance was preliminarily evaluated by the permeate flux stabilities. The module configuration design and air sparging used in the MDBR process were tested. Flux declines were observed for the thin flat-sheet hydrophobic membranes. Tubular membrane modules provided more stable permeate fluxes probably due to the turbulent condition generated from air sparging injected inside the tubular membrane bundles. The experiments with the submerged tubular MD module gave stable fluxes of approximately 5,L/m2 h over 2,weeks at a bioreactor temperature of 56,°C. The total organic carbon in the permeate was consistently lower than 0.7,mg/L for all experiments. [source] L -Lysine Monohydrochloride Syrup Concentration using a Membrane Hybrid Process of Ultrafiltration and Vacuum Membrane DistillationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2008O. Bakhtiari Abstract The development of energy saving membrane separation processes is finding a unique position in process industries. One of the important areas where they are employed is the biotechnology industry. This industry has its own specifications and requirements, e.g., levels of diluteness, thermal, chemical and shear fragility. Membrane separation processes have the characteristics necessary to match these specifications and needs. In this research, the determination of the experimental concentration of L -Lysine monohydrochloride (L -lysine-HCl) syrup was investigated using ultrafiltration (UF) and vacuum membrane distillation (VMD) hybrid membrane processes. Four parameters that are known to have significant influence on the UF process were examined, i.e., pressure difference across the membrane, feed concentration of L -lysine-HCl, feed velocity on the membrane surface, and pH. For the VMD unit, pressure difference and pH were replaced with feed temperature and vacuum pressure on the permeate side of membrane. Each process was carried out separately and the results were used to design a bench-scale process. In order to save time and money, the Taguchi method of experimental design was employed. The effects of feed concentration, pressure difference across the membrane, feed velocity on the membrane surface, and pH on the target variable, i.e., the membrane flux, in the UF process were 39.93, 38.65, 9.36, and 9.59,%, respectively. For the VMD process, these values were 64.79, 22.16, 6.21, and 2.14,% for feed temperature, feed concentration, vacuum pressure on the permeate side, and feed velocity on the membrane surface, respectively. [source] | ||||||||||