Performance modeling of direct contact membrane distillation (DCMD) seawater desalination process using a commercial composite membrane

Abstract

This paper presents the development of a rigorous theoretical model to predict the transmembrane flux of a flat sheet hydrophobic composite membrane, comprising both an active layer of polytetrafluoroethylene and a scrim-backing support layer of polypropylene, in the direct contact membrane distillation (DCMD) process. An integrated model includes the mass, momentum, species and energy balances for both retentate and permeate flows, coupled with the mass transfer of water vapor through the composite membrane and the heat transfer across the membrane and through the boundary layers adjacent to the membrane surfaces. Experimental results and model predictions for permeate flux and performance ratio are compared and shown to be in good agreement. The permeate flux through the composite layer can be ignored in the consideration of mass transfer pathways at the composite membrane. The effect of the surface porosity and the thickness of active and support layers on the process performance of composite membrane has also been studied. Among these parameters, surface porosity is identified to be the main factor significantly influencing the permeate flux and performance ratio, while the relative influence of the surface porosity on the performance ratio is less than that on flux.

Ultrasonic-assisted removal of inorganic scales in high-salinity wastewater treatment using membrane distillation

“…Membrane distillation (MD) has become an important emerging water treatment technology and has the potential to replace conventional desalination techniques such as conventional desalination (MED, MSF) and reverse osmosis (RO) [1][2][3]. The MD has several advantages over conventional desalination technologies such as reverse osmosis (RO), multi-stage flash (MSF), multi effect distillation (MED), including low operating temperature and low hydraulic pressure, high salt rejection, and performance independent of high osmotic pressure for the feed water [1,[3][4][5][6][7][8][9][10][11][12][13][14]. For these reasons, MD is considered for various applications including sweater desalination to produce freshwater [1,3,[5][6][7][8]13,14].…”

“…The MD has several advantages over conventional desalination technologies such as reverse osmosis (RO), multi-stage flash (MSF), multi effect distillation (MED), including low operating temperature and low hydraulic pressure, high salt rejection, and performance independent of high osmotic pressure for the feed water [1,[3][4][5][6][7][8][9][10][11][12][13][14]. For these reasons, MD is considered for various applications including sweater desalination to produce freshwater [1,3,[5][6][7][8]13,14]. MD can also be used to treat the concentrated brine by RO because of its ability to treat high-salinity feed water.…”

Exploring the potential of commercial polyethylene membranes for desalination by membrane distillation

“…Other than the development of lab scale membranes, the investigation of potential commercial membranes may offer another perspective [21,22]. Therefore, in this study, several commercial polyethylene (PE) membranes have been employed to explore their prospect in DCMD for clean water production.…”

Experimental and Theoretical Investigations of a Novel Multi-Stage Direct Contact Membrane Distillation Module

“…In this study, therefore, an innovative MDCMD module under countercurrent-flow operation has been first designed and both theoretically and experimentally examined to demonstrate the feasibility and operability of module design for the desalination. A rigorous numerical model, which was developed in our previous work [11], has been modified to incorporate a thermal entrance effect near the inlet flow region of each stage for the performance prediction of MDCMD process. Further investigations have been conducted to identify the effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system.…”