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Start Over Descriptor "AGMD" Topic reverse osmosis
3 results on '"AGMD"'

1. Effects of membrane properties on water production cost in small scale membrane distillation systems

Author

Ali, Mohamed I., Summers, Edward K., Arafat, Hassan A., and V, John H. Lienhard

Subjects
*MEMBRANE distillation, *INDUSTRIAL costs, *SALINE water conversion, *REVERSE osmosis, *MASS transfer, *HEAT transfer, *POROSITY, *SALINITY, *THERMAL conductivity
Abstract

Abstract: Membrane distillation (MD) has shown potential as a desalination process. As a thermally driven membrane technology which runs at relatively low pressure and can tolerate high salinity feed, MD may be useful for desalination under condition for which reverse osmosis is not a good option. However, improved energy utilization and reduced water production cost in MD systems remains an important technical challenge. In this paper, we examine how optimization of the heat and mass transfer properties of the MD membrane can raise water flux and reduce unit energy consumption. Numerical modeling tools and factorial analysis are used to examine the effect of five MD membrane characteristics: porosity, tortuosity, thermal conductivity, pore diameter, and thickness. The water production cost (in USD/m3 of purified water) is calculated as a function of these parameters for a small-scale, single-stage MD process driven by waste heat. Two MD configurations were considered: Direct Contact MD (DCMD) and Air Gap MD (AGMD). All five membrane properties examined were found to have a significant effect on water production cost, although the magnitude of this effect was greatly dependent on the MD configuration. [Copyright &y& Elsevier]

Published
2012
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2. Membrane Distillation for the Production of Pharmaceutical-Grade Water—Investigation into the Application of AGMD and VMD

Author

Thomas Klein, F. Rögener, Hans-Jürgen Rapp, and Cornelius Nellessen

Subjects
020209 energy, Health, Toxicology and Mutagenesis, membrane distillation, 02 engineering and technology, Alternative process, Membrane distillation, Article, Water Purification, law.invention, 020401 chemical engineering, Tap water, law, 0202 electrical engineering, electronic engineering, information engineering, media_common.cataloged_instance, Wasser, 0204 chemical engineering, European union, Reverse osmosis, Process engineering, Distillation, media_common, VMD, business.industry, Public Health, Environmental and Occupational Health, Water, Membranes, Artificial, pure water, pharmaceutical-grade water, Pharmaceutical Preparations, Scientific method, AGMD, Medicine, Environmental science, ddc:500, Water quality, business
Abstract

The production of pharmaceutical ingredients, intermediates and final products strongly depends on the utilization of water. Water is also required for the purification and preparation of reagents. Each specific application determines the respective water quality. In the European Union, the European Pharmacopeia (Ph. Eur.) contains the official standards that assure quality control of pharmaceutical products during their life cycle. According to this, the production of water for pharmaceutical use is mainly based on multi-stage distillation and membrane processes, especially, reverse osmosis. Membrane distillation (MD) could be an alternative process to these classical methods. It offers advantages in terms of energy demand and a compact apparatus design. In the following study, the preparation of pharmaceutical-grade water from tap water in a one-step process using MD is presented. Special emphasis is placed on the performance of two different module designs and on the selection of optimum process parameters.

Published
2021
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3. Power effect of ultrasonically vibrated spacers in air gap membrane distillation: Theoretical and experimental investigations

Author

Les Bowtell, Osamah Naji, Raed A. Al-Juboori, Sofiane Soukane, Alla Alpatova, Norreddine Ghaffour, Department of Built Environment, University of Southern Queensland, King Abdullah University of Science and Technology, Aalto-yliopisto, and Aalto University

Subjects
Materials science, Membrane permeability, Filtration and Separation, 02 engineering and technology, Membrane distillation, Analytical Chemistry, law.invention, 020401 chemical engineering, law, RO reject, Ultrasonically vibrated spacers, 0204 chemical engineering, Reverse osmosis, Groundwater, Filtration, Concentration polarization, Fouling, Membrane fouling, Chemical Engineering, 021001 nanoscience & nanotechnology, Membrane, Chemical engineering, AGMD, 0210 nano-technology, 0301 Analytical Chemistry, 0904 Chemical Engineering
Abstract

This study investigates the efficiency of low-power ultrasound in the range of 3.5–30.0 W to improve permeate flux and alleviate membrane fouling in an air–gap membrane distillation (AGMD) system. Natural groundwater and reverse osmosis (RO) reject water were fed into the AGMD system on which fouling experiments were conducted with hydrophobic polyvinylidene fluoride (PVDF) membrane. After 35 h of AGMD system operation with groundwater and RO reject water, fouling caused the permeate flux to decrease by 30% and 40% respectively. Concentration polarization, intermediate pore blocking, and cake filtration appear to be the main reasons for flux decline with both feedwater types. Ultrasound application for a short period of 15 min resulted in flux improvement by as high as 400% and 250% for RO reject and groundwater, respectively. Modelling of the heat and mass transfers showed that the flux increase was mainly due to membrane permeability improvements under ultrasonic vibration. Fouling visualisation using Scanning Electron Microscopy revealed that ultrasound effectively removed membrane fouling without compromising the membrane's structure. Importantly, permeate flux improvements with targeted low-power ultrasound appears to be proportionally higher than those of high-power ultrasound applied to the whole system, on a flux improvement per ultrasound W/m2 basis.

Published
2021
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