Techno-Economic Analysis of Vacuum Membrane Distillation for Seawater Desalination

Abstract

Seawater desalination is an affordable and viable solution to the growing freshwater scarcity problem in water scarce regions. The current study focuses on cost analysis of Vacuum Membrane Distillation (VMD) setup for removing salts from water. The membrane used in the flat sheet VMD module was Polytetrafluoroethylene (PTFE) with 250 mm × 200 mm dimensions and 165 µm thickness. The experiments were carried out with variations in parameters such as velocity, pressure, concentration, and temperature. For the cost analysis, the operational, maintenance, instrumentation, and capital cost of the lab model was considered and then upscaled. A range of experiments was performed for NaCl and KCl under variations of operating parameters. It was noted that, for the NaCl solution, the increase in temperature from 50 °C to 70 °C doubled the permeate flux. However, for the conditions tested, the concentration shift from 0.25 M to 0.75 M decreased the permeate flux by 1.4% because the increase in ion concentrations along the membrane lowers the vapor pressure, restricting the permeate flux. The results trend for the KCl solution was similar to the NaCl; at temperature T1, it was noted that increased concentration from 0.25 M to 0.75 M significantly reduces the permeate flow. The reduction in permeate flow was nonlinear for a given pressure 30 kPa and velocity 5.22 m/s, but linear for all other variables. It was also observed that with an increase in temperature from 60 °C to 70 °C, the permeate flux for concentration 0.25 M was 49% for all the combinations of pressure and velocity. In addition, permeate flow increased 53% from temperature 50 °C to 60 °C and 49% from temperature 60 °C to 70 °C for both the solutions at a concentration of 0.25 M. This shows that the temperature also had a profound impact on the permeate flux. The economic analysis and market survey shows that the cost of clean water at the lab level was high which can be significantly reduced using a large-scale setup providing 1,000,000 L/H of distilled water.

Recent Advances in Dopamine-Based Membrane Surface Modification and Its Membrane Distillation Applications

“…Theoretically, only water vapor can pass through the membrane pore, and it can achieve 100% interception of ions, macromolecules, colloids, cells and other non-volatile substances [1][2][3]. Moreover, it can collect renewable energy, including solar energy, geothermal energy and low-grade waste heat, as a heat source to provide heat for the feed side, which means that the process has higher energy efficiency and lower operating costs [4][5][6]. Due to these advantages of membrane distillation, the process has great application potential in the fields of seawater desalination, wastewater treatment, ultrapure water production, the food industry and the medical industry [7,8].…”

Experimental Investigation of a Plate–Frame Water Gap Membrane Distillation System for Seawater Desalination

“…Depending on the approach for vapor condensation, MD can be classified into four major configurations [ 13 ], including air gap membrane distillation (AGMD) [ 14 , 15 , 16 , 17 ], sweeping-gas membrane distillation (SGMD) [ 12 , 18 , 19 , 20 , 21 , 22 ], direct contact membrane distillation (DCMD) [ 12 , 23 , 24 , 25 , 26 , 27 ], and vacuum membrane distillation (VMD) [ 12 , 28 , 29 , 30 , 31 , 32 ]. Recently, a new MD configuration that combined the features of AGMD and DCMD processes was introduced and named water gap membrane distillation (WGMD) [ 33 , 34 , 35 ] or permeate gap membrane distillation (PGMD) [ 36 , 37 , 38 , 39 ], or liquid gap membrane distillation (LGMD) [ 40 , 41 , 42 , 43 ].…”

Recent Studies of Membranes for Liquids Separation and Water Treatment

“…Among various desalination technologies, vacuum membrane distillation is a relatively cost-effective method that can enable a high water vapor flux under sufficiently high vacuum levels [ 14 , 15 ]. In a study by Idrees et al, techno-economic analyses were conducted on vacuum membrane distillation for removing NaCl and KCl salts from seawater [ 16 ]. The lab-scale experiments were conducted utilizing a polytetrafluoroethylene (PTFE) membrane under a variation of different parameters, including temperature, concentration, pressure, and velocity [ 16 ].…”

“…In a study by Idrees et al, techno-economic analyses were conducted on vacuum membrane distillation for removing NaCl and KCl salts from seawater [ 16 ]. The lab-scale experiments were conducted utilizing a polytetrafluoroethylene (PTFE) membrane under a variation of different parameters, including temperature, concentration, pressure, and velocity [ 16 ]. Subsequently, economic investigations were performed based on the experimental results in combination with a market survey to estimate the costs of an up-scale vacuum membrane distillation plant.…”

“…Subsequently, economic investigations were performed based on the experimental results in combination with a market survey to estimate the costs of an up-scale vacuum membrane distillation plant. The results indicated that the costs associated with obtaining clean water using lab-scale vacuum membrane distillation can be reduced by utilizing a large-scale setup [ 16 ].…”