Vacuum membrane distillation for seawater desalination: could it compete with reverse osmosis?

2003 ◽  
Vol 3 (5-6) ◽  
pp. 57-66 ◽  
Author(s):  
D. Wirth ◽  
C. Cabassud
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Membrane Distillation ◽  
Hollow Fibre ◽  
Permeate Flux ◽  
Seawater Desalination ◽  
Industrial Plants ◽  
Low Energy Consumption ◽  
In Series ◽  
Vacuum Membrane Distillation

This work addresses the potentialities of vacuum membrane distillation (VMD) using hollow fibre membranes for seawater desalination. Experiments were carried out with a synthetic salty water containing a concentration of NaCl from 0 up to 300 g/L. A Microza (Pall) hollow fibre module was used. Experimental results show that, for this module, concentration polarisation and heat transfer limitations are not significant and do not modify the permeate flux. This is a great advantage over reverse osmosis (RO). Energy consumption was then studied using computations based on modelling. Two different industrial plants were considered: the first one consisted of hollow fibre modules arranged in series and operated in a single-pass. The second one was designed for a discontinuous operation using a circulation loop. Computations clearly show the interest (low energy consumption) of VMD for seawater desalination in comparison with RO.

Sintering process investigation during polytetrafluoroethylene hollow fibre membrane fabrication by extrusion method

2017 ◽  
Vol 29 (9) ◽  
pp. 1069-1082 ◽  
Author(s):  
Jingxuan Jia ◽  
Guodong Kang ◽  
Tong Zou ◽  
Meng Li ◽  
Meiqing Zhou ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Hollow Fibre ◽  
Test Results ◽  
Sintering Process ◽  
Permeate Flux ◽  
Hollow Fibre Membrane ◽  
Membrane Fabrication ◽  
Fibre Membrane ◽  
Vacuum Membrane Distillation ◽  
Extrusion Method

In this study, the effect of sintering conditions including manner, temperature and duration on properties of polytetrafluoroethylene (PTFE) hollow fibre membrane fabricated by extrusion method was intensively investigated. Different from un-sintered and relaxed sintered, the fixed sintered PTFE hollow fibre membrane was observed to generate a uniform ‘fibril–node’ porous structure and a main crystal transformation to folded chain crystal with smaller size. Consequently, it was found that for fixed setting sintering, both temperature increase from 340°C to 400°C and duration prolongation obviously improved pore size, ethanol permeation performance and mechanical strength. Additionally, the test results revealed that the membrane sintered below virgin melting point (350°C) had a noticeable higher porosity but poorer ethanol permeation performance that could be primarily attributed to increased ratio of closed pore. The sintering condition exhibited evident influence on PTFE hollow fibre membrane thermal stability, though it showed no alteration to the thermal decomposition of PTFE. The obtained PTFE hollow fibre membrane was tested to evaluate their vacuum membrane distillation (VMD) performances. It was found that PTFE membrane from lower sintering temperature delivered a better salt rejection; on the other hand, the permeate flux was improved by increased vacuum pressure during VMD operation.

scholarly journals Electrospun Nanostructured Membrane Engineering Using Reverse Osmosis Recycled Modules: Membrane Distillation Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1601
Author(s):  
Jorge Contreras-Martínez ◽  
Carmen García-Payo ◽  
Mohamed Khayet
Keyword(s):  
Reverse Osmosis ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Electrospinning Technique ◽  
Salt Rejection ◽  
Rejection Factor ◽  
Nanofibrous Membranes ◽  
Membrane Engineering ◽  
Desalination Plants

As a consequence of the increase in reverse osmosis (RO) desalination plants, the number of discarded RO modules for 2020 was estimated to be 14.8 million annually. Currently, these discarded modules are disposed of in nearby landfills generating high volumes of waste. In order to extend their useful life, in this research study, we propose recycling and reusing the internal components of the discarded RO modules, membranes and spacers, in membrane engineering for membrane distillation (MD) technology. After passive cleaning with a sodium hypochlorite aqueous solution, these recycled components were reused as support for polyvinylidene fluoride nanofibrous membranes prepared by electrospinning technique. The prepared membranes were characterized by different techniques and, finally, tested in desalination of high saline solutions (brines) by direct contact membrane distillation (DCMD). The effect of the electrospinning time, which is the same as the thickness of the nanofibrous layer, was studied in order to optimize the permeate flux together with the salt rejection factor and to obtain robust membranes with stable DCMD desalination performance. When the recycled RO membrane or the permeate spacer were used as supports with 60 min electrospinning time, good permeate fluxes were achieved, 43.2 and 18.1 kg m−2 h−1, respectively; with very high salt rejection factors, greater than 99.99%. These results are reasonably competitive compared to other supported and unsupported MD nanofibrous membranes. In contrast, when using the feed spacer as support, inhomogeneous structures were observed on the electrospun nanofibrous layer due to the special characteristics of this spacer resulting in low salt rejection factors and mechanical properties of the electrospun nanofibrous membrane.

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.

scholarly journals Optimization of Energy Efficiency, Operation Costs, Carbon Footprint and Ecological Footprint with Reverse Osmosis Membranes in Seawater Desalination Plants

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 781
Author(s):  
Federico Leon ◽  
Alejandro Ramos ◽  
S. Ovidio Perez-Baez
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Reverse Osmosis ◽  
Ecological Footprint ◽  
Energy Savings ◽  
Seawater Desalination ◽  
Operation Costs ◽  
Private And Public ◽  
Desalination Plants ◽  
Reverse Osmosis Membranes

This article shows the optimization of the reverse osmosis process in seawater desalination plants, taking the example of the Canary Islands, where there are more than 320 units of different sizes, both private and public. The objective is to improve the energy efficiency of the system in order to save on operation costs as well as reduce the carbon and ecological footprints. Reverse osmosis membranes with higher surface area have lower energy consumption, as well as energy recovery systems to recover the brine pressure and introduce it in the system. Accounting for the operation, maintenance and handling of the membranes is also important in energy savings, in order to improve the energy efficiency. The energy consumption depends on the permeate water quality required and the model of the reverse osmosis membrane installed in the seawater desalination plant, as it is shown in this study.

scholarly journals A small shipborne desalination plant based on the principle of loop heat pipe

2020 ◽  
Vol 165 ◽  
pp. 01003
Author(s):  
Tongyao Miao ◽  
Zheng Fang ◽  
Lingzhi Feng ◽  
Yunhui Peng
Keyword(s):  
Energy Consumption ◽  
Heat Pipe ◽  
Fresh Water ◽  
High Energy ◽  
Loop Heat Pipe ◽  
Seawater Desalination ◽  
Low Energy Consumption ◽  
New Type ◽  
Emergency Equipment ◽  
High Energy Consumption

As is well-known, the problem of fresh water has always been a major problem for ocean navigation. The existing marine seawater desalination equipment generally has the disadvantages of large volume, high energy consumption and easy to pollute the environment. Based on this, we proposed a small seawater desalination system based on phase change to enhance heat transfer, which realized low temperature and low energy consumption by using the loop heat pipe technology, a new type of heat sink type spoiler evaporator and an integrated equal-heat plate fin condenser. The device is suitable for islands, fishing boats and other complicated areas where power is scarce and fresh water resources are scarce. It can also be used as fresh water emergency equipment for large ships, saving energy and being portable.

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.

scholarly journals Analyzing the Energy Consumption, GHG Emission, and Cost of Seawater Desalination in China

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 463 ◽  
Author(s):  
Xuexiu Jia ◽  
Jiří Klemeš ◽  
Petar Varbanov ◽  
Sharifah Wan Alwi
Keyword(s):  
Energy Consumption ◽  
Water Supply ◽  
Reverse Osmosis ◽  
Process Integration ◽  
Ghg Emissions ◽  
Water Desalination ◽  
Heat Integration ◽  
Seawater Desalination ◽  
Ghg Emission ◽  
Product Cost

Seawater desalination is considered a technique with high water supply potential and has become an emerging alternative for freshwater supply in China. The increase of the capacity also increases energy consumption and greenhouse gases (GHG) emissions, which has not been well investigated in studies. This study has analyzed the current development of seawater desalination in China, including the capacity, distribution, processes, as well as the desalted water use. Energy consumption and GHG emissions of overall desalination in China, as well as for the provinces, are calculated covering the period of 2006–2016. The unit product cost of seawater desalination plants specifying processes is also estimated. The results showed that 1) The installed capacity maintained increased from 2006 to 2016, and reverse osmosis is the major process used for seawater desalination in China. 2) The energy consumption increased from 81 MWh/y to 1,561 MWh/y during the 11 years. The overall GHG emission increase from 85 Mt CO2eq/y to 1,628 Mt CO2eq/y. Tianjin had the largest GHG emissions, following are Hebei and Shandong, with emissions of 4.1 Mt CO2eq/y, 2.2 Mt CO2eq/y. and 1.0 Mt CO2eq/y. 3) The unit product cost of seawater desalination is higher than other water supply alternatives, and it differentiates the desalination processes. The average unit product cost of the reverse osmosis process is 0.96 USD and 2.5 USD for the multiple-effect distillation process. The potential for future works should specify different energy forms, e.g. heat and power. Alternatives of process integration should be investigated—e.g. efficiency of using the energy, heat integration, and renewables in water desalination, as well as the utilization of total site heat integration.

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