Ahmad Alsaadi

• Assistant Professor
• Assistant Professor at Jeddah University

The concept and analysis of integrating membrane distillations (MD) with reversal once-through Multistage Flash (RV-MSF) desalination is presented. The analysis is based on numerical simulation. The MD vessels are integrated into the terminal ends of the RV-MSF system to leverage the thermal energy associated with these terminal streams. Hybridisat...

In this study, we propose a novel module design to integrate forward osmosis (FO) and membrane distillation (MD). The two processes are sealed in one module and operated simultaneously, making the system compact and suitable for a wide range of applications. To evaluate the system under large-scale module operating conditions, FO and MD experiments...

A novel air gap membrane distillation (AGMD) module in which non-porous polymeric hollow fiber condensers (i.e., heat exchangers) were inserted inside the porous hollow fiber membranes was developed. In this module the hot feed was circulated on the outer side of the membrane's lumen and the coolant was circulated counter-currently inside the conde...

The major challenge of membrane distillation (MD) is the low gain output ratio (GOR) resulting from the high thermal energy requirement and the low water production. Here, the use of hot streams such as geothermal groundwater or produced water that are suitable to be treated by MD without the need for thermal energy input is discussed. Hot groundwa...

The coupling of heat and mass transfer in membrane distillation (MD) process makes enhancing water vapor flux and determining MD membrane mass transfer coefficient (MTC) fairly challenging due to the development of temperature gradient near the membrane surface, referred to as temperature polarization (TP). As a result, the change in feed temperatu...

The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concen...

In order to improve water production of membrane distillation (MD), the development of high performance membrane having better mass transfer and enhancement of convection heat transfer in MD module have been continuously investigated. This paper presents the relationship between the heat and mass transfer resistance across the membrane and the perf...

The low thermal efficiency and low water production are among the major challenges that prevent membrane distillation (MD) process from being commercialized. In an effort to design an efficient multi-stage direct contact MD (DCMD) unit through mathematical simulation, a new phenomenon that we refer to as total water production capacity inversion (W...

The current study aims to highlight the effect of flow pattern on the variations of permeate fluxes over the membrane surface during desalination in a direct contact membrane distillation (DCMD) flat module. To do so, a three dimensional (3D) Computational Fluid Dynamics (CFD) model with embedded pore scale calculations is implemented to predict fl...

Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-para...

This work proposes a mathematical dynamic model for the direct contact membrane distillation (DCMD) process. The model is based on a 2D Advection–Diffusion Equation (ADE), which describes the heat and mass transfer mechanisms that take place inside the DCMD module. The model studies the behavior of the process in the time varying and the steady sta...

Provisional US Patent, Serial No: 62/152,061; April 15, 2015.

Provisional US Patent, Serial N: 62/121

Provisional US Patent, Serial No: 62/095, 136; Dec 22, 2014

A submerged membrane distillation (SMD) process for fresh water production from Red Sea water using commercially available hollow fiber membranes has been successfully employed and compared with the conventional direct contact membrane distillation (DCMD) process. The hollow fiber membranes have been characterized for its morphology using field eff...

Membrane distillation requires a highly porous hydrophobic membrane with low surface energy. In this paper, we compare the direct contact membrane distillation (DCMD) performances of four different types of in-house fabricated hollow fiber membranes and two different commercially available hollow fiber membranes. Hollow fiber membranes are fabricat...

Theoretical and experimental validation of a water gap membrane distillation (WGMD) process has been proposed and successfully tested for seawater desalination. It has been observed that, employing water in the air gap between the membrane and condensation plate of an air gap membrane distillation (AGMD) module, there is a significant enhancement o...

The flux performance of different hydrophobic microporous flat sheet commercial membranes made of poly tetrafluoroethylene (PTFE) and poly propylene (PP) was tested for Red Sea water desalination using the direct contact membrane distillation (DCMD) process, under bench scale (high ΔT) and large scale module (low ΔT) operating conditions. Membranes...

Polyvinylidene fluoride hollow fiber and nanofibrous membranes are engineered and successfully fabricated using dry-jet wet spinning and electrospinning techniques, respectively. Fabricated membranes are characterized for their morphology, average pore size, pore size distribution, nanofiber diameter distribution, thickness, and water contact angle...

embrane distillation (MD) is considered as an attractive new desalination technology, which combines the advantages of conventional distillation and membrane based technologies. However, despite the MD process have been under investigation for several decades, it has still not been commercialized, even at small scale applications. So far, only a fe...

Hydrophobic membranes based on fluorinated polyoxadiazole and polytriazole were manufactured as flat-sheet and hollow fibers as well as electrospun membranes. Electrospun membranes had the highest water fluxes when tested for direct contact membrane distillation with Red Sea water. The values were as high as 80 L m-2 h-1 . Salt selectivity as high...

A new type of membrane distillation (MD) module, namely material gap membrane distillation (MGMD), has been proposed and successfully tested for seawater desalination application. It has been observed that by employing appropriate materials in the air gap between the membrane and condensing plate of an air gap membrane distillation (AGMD) module, t...

Abstract A one dimensional (1-D) air gap membrane distillation (AGMD) model for flat sheet type modules has been developed. This model is based on mathematical equations that describe the heat and mass transfer mechanisms of a single-stage AGMD process. It can simulate AGMD modules in both co-current and counter-current flow regimes. The theoretica...

A new module design for membrane distillation, namely material gap membrane distillation (MGMD), for seawater desalination has been proposed and successfully tested. It has been observed that employing appropriate materials between the membrane and the condensation plate in an air gap membrane distillation (AGMD) module enhanced the water vapor flu...

Porous hollow fiber membranes were fabricated from fluorinated polyoxadiazole and polytriazole by a dry–wet spinning method for application in desalination of Red Sea water by direct contact membrane distillation (DCMD). The data were compared with commercially available hollow fiber MD membranes prepared from poly(vinylidene fluoride). The membran...

Hydrophobic microporous flat sheet membranes made of poly tetrafluoroethylene (PTFE) and poly propylene (PP) were explored for desalting real Red Sea water using direct contact membrane distillation (DCMD) process. This paper describes the highest ever reported flux performance while using real seawater as a feed solution and deionized water as a p...

A one dimensional (1-D) air gap membrane distillation (AGMD) model for flat sheet type modules was developed. This model is based on mathematical equations that describe the heat and mass transfer mechanisms of a single pass AGMD process. The validity of the model was tested against several experimental measurements made at different operating cond...

Aromatic fluorinated polyoxadiazoles (F-POD) and polytriazoles (F-PT) were synthesized and for the first time manufactured into porous membranes by phase inversion and by electrospinning. The phase inversion F-POD membranes had a mean flow pore size (MFP) of 51 nm, while for F-PT it was around 74 nm. The electrospun membranes had a much larger pore...

Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of e...