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Abstract : Filtering Brackish Water by Photovoltaic-Powered Membrane
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Abstract: Photovoltaic-powered membrane was taken to filter brackish water. Effect of ammonia concentration, pressure and salinity on ammonia and total dissolved solids (TDS) removal, water recovery and energy consumption had been investigated. Results show that ammonia concentration did not influence ammonia and TDS removal, water recovery, and energy consumption obviously. Results of ammonia concentration of 10, 20 and 35 mg/l were similar to that of 5 mg/l. For salinity, the better filtration was achieved when the concentration of salinity was lower. With increment of pressure, ammonia and TDS removal increased simultaneously. The ammonia and TDS removal of more than 98% attained with the water recovery of 40.6% at the energy consumption of 2.0 kWh/m3. It illustrates that salinity and pressure were definitely crucial to brackish water filtration with photovoltaic-powered membrane. Keywords: Photovoltaic-powered membrane, Reverse osmosis, Brackish water, Salinity, Total dissolved solids (TDS), Energy consumption. Download Full Article |
Abstract : The Economics of Reverse Osmosis Desalination Projects
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Abstract: Desalination applications based on reverse osmosis (RO) technology today comprise over 50% of the capacity of all desalination systems worldwide and represent 75-85% of new desalination projects being implemented. The major reason for the shift in desalination projects to RO technology is the high energy efficiency of the RO process. There are three major application categories of large capacity, RO-based desalination projects: brackish RO; advanced municipal wastewater reclamation; and seawater RO. In the two first categories (brackish RO and wastewater reclamation), the systems’ configuration and equipment components are well defined. Therefore, project costs and operating expenses are fairly predictable. In seawater RO desalination systems, the RO process configuration is also very similar; however, some variability exists regarding the configuration of seawater water delivery and feed water pretreatment. The rest of the system’s components and system operation methods are very uniform. However, an evaluation of published cost data of medium- to large-scale water RO desalination projects illustrates significant variability in costs of desalination systems. This paper will analyze current economic conditions of seawater desalination, and highlight the limitations and possibilities of additional improvements of the economics of the SWRO desalination process. Keywords: Desalination, Reverse osmosis, energy, investment, cost. Download Full Article |
Abstract : EDITORIAL: Special Issue on the Membranes for Carbon Dioxide Separation / Capture Applications
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Editorial Download Full Article |
Abstract : CO2 Permeation Behavior through Carbon Membranes: A Short Review of the Progress during the Last Decade
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Abstract: Although carbon dioxide is not classified as a toxic or harmful gas the necessity for its capture is enforced not only by scientists but also by governments worldwide. In this attempt the technologies which are proposed to attend this role are various. Contrary to the traditional thermal methods (distillation, adsorption, cryogenic), which require high energy sources, the membrane technology seems to be the prevalent solution mainly thanks to its low operation cost. To this aim, both polymeric and inorganic membranes are reported as good candidates for CO2 separation–capture. The main advantages of the inorganic membranes, in terms of the polymeric, are their higher selectivity factors and the better stability at both high temperatures and chemical environments. The preparation of the carbon membranes takes place mainly by the controlled pyrolysis of different thermosetting polymeric materials and the final configuration can be divided into the following configurations: i) flat sheet membranes, ii) supported on tube membranes, iii) capillary membranes and iv) hollow fiber membranes. During the last fifty years, more attention has been devoted, not only for the simultaneous increase of both permeability and selectivity factors but also for the large–scale production of crack free carbon membranes. The reproductivity is also one critical point which has to be achieved if we really aim for the industrial application of the carbon gas selective membranes. Therefore, carbon membranes have the potential to be the materials of the future for many gas separation processes including the one of carbon dioxide separation–capture. This paper is reviewing the development and the achievements of the carbon membranes in the direction of the CO2 separation giving emphasis on the last 10 years. Keywords: CO2 permeation, CO2 selectivity, inorganic membranes, carbon membranes, gas separation.v. Download Full Article |
Abstract : Combination of Adsorption-Diffusion Model with Computational Fluid Dynamics for Simulation of a Tubular Membrane Made from SAPO-34 Thin Layer Supported by Stainless Steel for Separation of CO2 from CH4
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Abstract: Modeling of CO2/CH4 separation using SAPO-34 tubular membrane was performed by computational fluid dynamics. The Maxwell-Stefan equations and Langmuir isotherms were used to describe the permeate flux through the membrane and the adsorption-diffusion, respectively. Three-dimensional Navier-Stokes momentum balances in feed and permeate side coupled with adsorption-diffusion equations from the membrane were simultaneously solved by ANSYS FLUENT software. The velocity and concentration profiles were determined in both feed and permeate sides. There was a good agreement between simulation and experimental results and root mean square deviation for CH4 and CO2 are 0.13 and 0.1 (mmol m-2 s-1), respectively. The concentration polarization effect was observed in the results. The effect of the process variables were investigated to find out the most influential parameters in permeation and purity. The impact of operating conditions on separation were studied and showed that for enhancement of separation efficiency of CO2 from CH4, feed pressure, feed flow rate and tube radius and number of membrane modules in series should be increased, whereas flow configuration has less significant effect. Keywords: Computational fluid dynamic, tubular zeolite membrane, CO2/CH4 separation, SAPO-34, Adsorption-diffusion mechanismv. |