scholarly journals Energy evaluation and treatment efficiency of vacuum membrane distillation for brackish water desalination

2014 ◽  
Vol 5 (2) ◽  
pp. 119-131
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar
Keyword(s):  
Brackish Water ◽  
Potable Water ◽  
Membrane Separation ◽  
Rapid Development ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Treated Wastewater ◽  
Permeate Flux ◽  
Effective Parameters ◽  
Vacuum Membrane Distillation

Strict environmental regulations have led to the rapid development of membrane separation technologies for the production of potable water, for industrial water supply, and for the reuse and discharge of treated wastewater. Promotion of water recycling and the provision of potable water from brackish water prevent significant negative effects on the environment and drinking water supplies. This study is intended to describe and compare a sustainable technology for brackish water treatment. Among the four configurations of the membrane distillation process, vacuum membrane distillation (VMD) produces higher flux and results in a low fouling rate. It comprises evaporation and condensation that mimics what occurs in nature. Mathematical models proposed for the VMD transport mechanisms are incorporated to predict the actual experimental flux. The response of the flux rate to various process operating parameters is demonstrated. Variation of effective parameters is investigated in terms of energy consumption. The data indicate that the permeate flux is highly responsive to the variation of pressure and temperature. VMD enables the removal of 99.9% of total dissolved solids from natural and contaminated water sources. The findings are that the quality of the permeate water from all sources was at acceptable standards for potable use.

scholarly journals Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Adnan Alhathal Alanezi ◽  
H. Abdallah ◽  
E. El-Zanati ◽  
Adnan Ahmad ◽  
Adel O. Sharif
Keyword(s):  
Flow Rate ◽  
Membrane Distillation ◽  
Membrane Module ◽  
Water Desalination ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Vacuum Degree ◽  
Flat Sheet ◽  
Vacuum Membrane Distillation ◽  
Feed Temperature

A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes.

A review on membrane applications and transport mechanisms in vacuum membrane distillation

2017 ◽  
Vol 34 (1) ◽  
Author(s):  
Rakesh Baghel ◽  
Sushant Upadhyaya ◽  
Kailash Singh ◽  
Satyendra P. Chaurasia ◽  
Akhilendra B. Gupta ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Critical Evaluation ◽  
Experimental Studies ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Separation Processes ◽  
Vacuum Membrane Distillation ◽  
Polarization Coefficient ◽  
The Impact

AbstractThe main aim of this article is to provide a state-of-the-art review of the experimental studies on vacuum membrane distillation (VMD) process. An introduction to the history of VMD is carried out along with the other membrane distillation configurations. Recent developments in process, characterization of membrane, module design, transport phenomena, and effect of operating parameters on permeate flux are discussed for VMD in detail. Several heat and mass transfer correlations obtained by various researchers for different VMD modules have been discussed. The impact of membrane fouling with its control in VMD is discussed in detail. In this paper, temperature polarization coefficient and concentration polarization coefficient are elaborated in detail. Integration of VMD with other membrane separation processes/industrial processes have been explained to improve the performance of the system and make it more energy efficient. A critical evaluation of the VMD literature is incorporated throughout this review.

Brackish Water Desalination by Air-Sweep Vacuum Membrane Distillation

2013 ◽  
Vol 781-784 ◽  
pp. 2084-2086
Author(s):  
Guo Fu Sun ◽  
Jing Li Xu ◽  
Chun Hua Sui ◽  
Hong Yan Si
Keyword(s):  
Flow Rate ◽  
Brackish Water ◽  
Produced Water ◽  
Air Flow ◽  
Operating Parameter ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Air Flow Rate ◽  
Vacuum Membrane Distillation ◽  
Condensed Water

An air sweep vacuum membrane distillation process was used to treat brackish water desalination. The only operating parameter of the apparatus is the sweeping air flow rate. The effect of sweeping air flow rate on desalination was observed. The produced/condensed water rate was about 2.5 g/h for the PP module. The conductivity of produced water was about 92 μs·cm-1, the salt rejection was above 95%.

scholarly journals Capillary Polypropylene Membranes for Membrane Distillation

Fibers ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Continuous Process ◽  
Negative Influence ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Porous Membranes ◽  
Surface Porosity ◽  
Permeate Flux ◽  
Thermally Induced

Only nonwetted porous membranes can be used in membrane distillation. The possibility of application in this process the capillary polypropylene membranes manufactured by thermally-induced phase separation was studied. The performance of a few types of membranes available commercially was presented. The resistance of the membranes to wetting was tested in the continuous process of water desalination. These studies were carried out for 1000 h without module cleaning. The presence of scaling layer on the membranes surface was confirmed by Scanning Electron Microscope observations. Both the permeate flux and distillate conductivity were almost not varied after the studied period of time, what indicates that the used membranes maintained their nonwettability, and the negative influence of scaling was limited. The role of surface porosity on the pore wetting and influence of membrane wettability on the quality of the distillate obtained were discussed.

scholarly journals An Experimental and Theoretical Study on Separations by Vacuum Membrane Distillation Employing Hollow-Fiber Modules

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 947 ◽  
Author(s):  
Anthoula Karanasiou ◽  
Margaritis Kostoglou ◽  
Anastasios Karabelas
Keyword(s):  
Process Model ◽  
Flow Direction ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Solution Temperature ◽  
Feed Water ◽  
System Productivity ◽  
Capillary Membrane ◽  
Vacuum Membrane Distillation ◽  
By Products

Vacuum membrane distillation (VMD) is an attractive variant of the novel membrane distillation process, which is promising for various separations, including water desalination and bioethanol recovery through fermentation of agro-industrial by-products. This publication is part of an effort to develop a capillary membrane module for various applications, as well as a model that would facilitate VMD process design. Experiments were conducted in a laboratory pilot VMD unit, comprising polypropylene capillary-membrane modules. Performance data, collected at modest temperatures (37 °C to 65 °C) with deionized and brackish water, confirmed the improved system productivity with increasing feed-water temperature; excellent salt rejection was obtained. The recovery of ethanol from ethanol-water mixtures and from fermented winery by-products was also studied, in continuous, semi-continuous, and batch operating modes. At low-feed-solution temperature (27–47 °C), ethanol-solution was concentrated 4 to 6.5 times in continuous operation and 2 to 3 times in the semi-continuous mode. Taking advantage of the small property variation in the module axial-flow direction, a simple VMD process model was developed, satisfactorily describing the experimental data. This VMD model appears to be promising for practical applications, and warrants further R&D work.

scholarly journals Large-scale brackish water desalination plants in Gaza Strip: assessments and improvements

2013 ◽  
Vol 3 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Yunes Mogheir ◽  
Ahmad A. Foul ◽  
A. A. Abuhabib ◽  
A. W. Mohammad
Keyword(s):  
Brackish Water ◽  
Large Scale ◽  
Potable Water ◽  
Gaza Strip ◽  
Water Desalination ◽  
Saline Groundwater ◽  
Operational Conditions ◽  
The Gaza Strip ◽  
Desalination Plants

Water scarcity is a serious challenge in the Gaza Strip, a region that is mostly considered to be semi-arid. In this region, the population's options for provision of potable water are limited to desalination of saline groundwater. Six large brackish water desalination plants (BWDPs) and one seawater desalination plant are operating and providing drinking water along with small private plants. The BWDPs were assessed in terms of operational conditions and quality of their feed and permeate with the aim of estimating essential improvements required as well as performance significance. All these plants are reverse osmosis plants and their operational conditions are similar in terms of production, recovery rate, and energy consumption. The quality of the plants’ feed was found not to comply with WHO and Palestinian Standards in most cases, unlike the permeate from all plants. The assessment made through this study assists in better understanding of the current situation of the large-scale desalination plants in Gaza and recommending essential improvements needed to increase water production of these plants without increasing abstraction and feed quantities. In addition, multi-criteria analysis used to evaluate BWDPs performance may assist in prioritizing improvements application.

scholarly journals Enhancement of brackish water desalination using hybrid membrane distillation and reverse osmosis systems

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0205012 ◽  
Author(s):  
Emad Ali ◽  
Jamel Orfi ◽  
Abdullah Najib ◽  
Jehad Saleh
Keyword(s):  
Reverse Osmosis ◽  
Brackish Water ◽  
Membrane Distillation ◽  
Hybrid Membrane ◽  
Water Desalination

Characteristic and Performance of Polyvinylidene Fluoride Membranes Blended with Lithium Chloride in Direct Contact Membrane Distillation

2014 ◽  
Vol 69 (9) ◽  
Author(s):  
S. O. Lai ◽  
K. C. Chong ◽  
K. M. Lee ◽  
W. J. Lau ◽  
B. S. Ooi
Keyword(s):  
Lithium Chloride ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Membrane Separation ◽  
Polymeric Materials ◽  
Membrane Distillation ◽  
Inversion Method ◽  
Permeate Flux ◽  
Separation Processes ◽  
Direct Contact Membrane Distillation

Membrane distillation (MD) is one of the recent rising membrane separation techniques adopted in the desalination and wastewater treatment. Unlike other pressure-driven separation processes such as reverse osmosis and nanofiltration, MD is a thermal-driven process which involves vapor pressure difference across the feed and permeates solutions. As such, MD requires low energy consumption. Hydrophobic polymeric materials such as polyvinylidene fluoride (PVDF) are frequently used in direct contact membrane distillation (DCMD) due to low surface energy and promising thermal resistance. In this study, the DCMD hollow fiber membranes were separately prepared with PVDF and PVDF blended with lithium chloride (LiCl) through dry/wet phase inversion method. Subsequently, the membranes were used in a DCMD process to remove sodium chloride (NaCl) under different feed inlet temperatures to examine the effect of LiCl additives on the neat membrane. The result showed that by adding LiCl into the neat membrane solution, the finger-like structure was change to a sponge-like structure with microvoids. Furthermore, the performance of the LiCl additive membrane in term of permeate flux was found to be 20% higher compared to that of the neat membrane. Other results of the membrane characteristics were also discussed.      

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