scholarly journals Numerical Simulation of Low Energy Direct Contact Membrane Distillation

2014 ◽  
Vol 07 (2) ◽  
Keyword(s):  
Direct Contact ◽  
Membrane Distillation ◽  
Low Energy ◽  
Model Parameters ◽  
Inlet Temperature ◽  
Vapor Flow ◽  
Two Dimensional ◽  
Counter Flow ◽  
Permeable Membrane ◽  
Direct Contact Membrane Distillation

Computational Fluid Dynamics (CFD) is used to study the steady state performance of Low Energy Direct Contact Membrane Distillation (DCMD). Two-dimensional numerical model with parallel and counter flow is developed. A case of fully developed pressure driven parabolic flow is considered entering the domain at the feed and the permeate sides at 40 C and 25 C, respectively. The model parameters were measured in the consideration of two dimensional fluid flow governed by the complete Navier-Stokes coupled with the energy equation for non-isothermal laminar flow. The feed stream is water at water 4% salinity, whereas the permeate stream is comprised of pure water. Across the membrane the temperature difference creates a pressure gradient responsible for the transport of vapor mass through the pours of the permeable membrane. The vapor flow is driven by two mechanisms, Knudson and Poiseuille flow. The membrane’s coefficients of DCMD membrane is evaluated along with the mass flux, heat flux, and temperature polarization factor and results showed a good agreement with the published theoretical work. In view of these plausible results, parametrical study is carried out accounting for parallel and counter flow, different flow rates and inlet temperature in an attempt to achieve optimal or better yield to the Multi stage flashing method.

The Effect of Net-Type Spacer on the Performance of Direct Contact Membrane Distillation System for Seawater Desalination: Heat and Mass Transfer Analysis

2019 ◽  
Author(s):  
Anas M. Alwatban ◽  
Ahmed M. Alshwairekh ◽  
Umar F. Alqsair ◽  
Abdullah A. Alghafis ◽  
Alparslan Oztekin
Keyword(s):  
Reynolds Number ◽  
Direct Contact ◽  
Concentration Polarization ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Membrane Distillation ◽  
Inlet Temperature ◽  
Vapor Permeation ◽  
Direct Contact Membrane Distillation ◽  
Distillation System

Abstract This work aims to study the effects of the net-type spacer on the performance of direct contact membrane distillation (DCMD) modules. Laminar and k-ω SST turbulence models are used to conduct simulations in three-dimensional modules with and without spacers. The spacers are placed in the middle of the feed and permeate channel. The net type spacers of diameter 0.25h and 0.5h were considered, where h is the height of each channel. The inlet temperature of the feed and the permeate channel set to 353 K and 293 K. The feed Reynolds number is varied (500, 1500) while the permeate Reynolds number is fixed at 330. We revealed that the presence of spacer in the flow channels mitigates both the temperature and the concentration polarization and yields higher vapor permeation. We also showed that the module containing larger size spacers yields better flux performance and lower level of temperature and concentration polarization. Moreover, the modules containing spacers become more efficient as the feed flow rate is increased.

Effect of Adding Functionalized Graphene on the Performance of PVDF Membrane in Direct Contact Membrane Distillation

2019 ◽  
Vol 801 ◽  
pp. 337-342 ◽  
Author(s):  
Mohamed Sameh Abdalghany Salem ◽  
Ahmed H. El-Shazly ◽  
Mohamed R. El-Marghany ◽  
Mohamed Nabil Sabry ◽  
Norhan Nady
Keyword(s):  
Contact Angle ◽  
Direct Contact ◽  
Fiber Diameter ◽  
Membrane Distillation ◽  
Inlet Temperature ◽  
Membrane Pore ◽  
Pvdf Membrane ◽  
Direct Contact Membrane Distillation ◽  
Pure Pvdf ◽  
Feed Inlet

In this paper, the effect of adding modified graphene nanoplatelets (MGNPs) as a filler on the characteristics and performance of Polyvinylidene fluoride (PVDF) membrane in a direct contact membrane distillation (DCMD) configuration was investigated. Both pure PVDF and PVDF/MGNPs composite (2%) membranes were fabricated by using electrospinning technique. The fabricated membranes were characterized using different analyses techniques such as SEM imaging, XRD analysis, static water contact angle as well as membrane porosity and liquid enter pressure measurements. Also, the average fiber diameter and the average membrane pore diameter were estimated using ImageJ software. The prepared PVDF/MGNPs composite membrane exhibited lower fiber diameter by about 5.7%, whereas the contact angle increased by 10 and liquid entry pressure increased by 11.7%. The membrane also showed an enhanced flux that reached about 19.8 kg/m2∙h at feed inlet temperature of 65°C, feed flow rate of 30 l/h. and feed inlet concentration of 10000 ppm. This represents about 13.46% improvement over the pure PVDF membrane at the same conditions. The produced membrane presents a viable alternative to commercial MD membranes.

Omniphobic palygorskite coated Janus membrane with enhanced fouling and wetting resistance for direct contact membrane distillation

Desalination ◽  
2021 ◽  
Vol 505 ◽  
pp. 114986
Author(s):  
Jiahui Zhang ◽  
Nan Li ◽  
Dong Wang ◽  
Jinmei Li ◽  
Yue Chen ◽  
...  
Keyword(s):  
Direct Contact ◽  
Membrane Distillation ◽  
Direct Contact Membrane Distillation

scholarly journals Concentration of Bioactive Phenolic Compounds in Olive Mill Wastewater by Direct Contact Membrane Distillation

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1808
Author(s):  
Rosa Tundis ◽  
Carmela Conidi ◽  
Monica R. Loizzo ◽  
Vincenzo Sicari ◽  
Rosa Romeo ◽  
...  
Keyword(s):  
Direct Contact ◽  
High Performance ◽  
Biological Properties ◽  
Membrane Distillation ◽  
Olive Mill Wastewater ◽  
High Concentration ◽  
Direct Contact Membrane Distillation ◽  
Reducing Activity ◽  
Β Carotene ◽  
Olive Mill

Olive mill wastewater (OMW), generated as a by-product of olive oil production, is considered one of the most polluting effluents produced by the agro-food industry, due to its high concentration of organic matter and nutrients. However, OMW is rich in several polyphenols, representing compounds with remarkable biological properties. This study aimed to analyze the chemical profile as well as the antioxidant and anti-obesity properties of concentrated fractions obtained from microfiltered OMW treated by direct contact membrane distillation (DCMD). Ultra-high performance liquid chromatography (UHPLC) analyses were applied to quantify some phenols selected as phytochemical markers. Moreover, α-Amylase, α-glucosidase, and lipase inhibitory activity were investigated together with the antioxidant activity by means of assays, namely β-carotene bleaching, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) diammonium salts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and Ferric Reducing Activity Power (FRAP) tests. MD retentate—which has content of about five times greater of hydroxytyrosol and verbascoside and about 7 times greater of oleuropein than the feed—was more active as an antioxidant in all applied assays. Of interest is the result obtained in the DPPH test (an inhibitory concentration 50% (IC50) of 9.8 μg/mL in comparison to the feed (IC50 of 97.2 μg/mL)) and in the ABTS assay (an IC50 of 0.4 μg/mL in comparison to the feed (IC50 of 1.2 μg/mL)).

Exploring the potential usage of 3D printed membranes combined with PVDF coating in direct contact membrane distillation

Desalination ◽  
2021 ◽  
pp. 115134
Author(s):  
Miaomiao Tian ◽  
Hellen De Coninck ◽  
Junyong Zhu ◽  
Yatao Zhang ◽  
Shushan Yuan ◽  
...  
Keyword(s):  
Direct Contact ◽  
Membrane Distillation ◽  
Direct Contact Membrane Distillation ◽  
3D Printed
Sign in / Sign up

Export Citation Format

Share Document