Experimental and Numerical Study of Water Distillation Performance of Small-Scale Direct Contact Membrane Distillation System

2017 ◽  
Author(s):  
Danielle Park ◽  
Elnaz Norouzi ◽  
Chanwoo Park
Keyword(s):  
Water Temperature ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Small Scale ◽  
Feed Water ◽  
Water Production ◽  
Water Distillation ◽  
Direct Contact Membrane Distillation ◽  
Feed Temperature ◽  
Feed Water Temperature

A small-scale Direct Contact Membrane Distillation (DCMD) system was built to investigate its water distillation performance for varying inlet temperatures and flow rates of feed and permeate streams, and salinity. A counterflow configuration between the feed and permeate streams was used to achieve an efficient heat exchange. A two-dimensional Computational Fluid Dynamics (CFD) model was developed and validated using the experimental results. The numerical results were compared with the experiments and found to be in good agreement. From this study, the most desirable conditions for distilled water production were found to be a higher feed water temperature, lower permeate temperature, higher flow rate and less salinity. The feed water temperature had a greater impact on the water production than the permeate water temperature. The numerical simulation showed that the water mass flux was maximum at the inlet of the feed stream where the feed temperature was the highest and rapidly decreased as the feed temperature decreased.

scholarly journals Direct Contact Membrane Distillation for Desalination Brine Solution

2018 ◽  
Vol 24 (11) ◽  
pp. 18
Author(s):  
Asrar Abdullah Hassan ◽  
Ahmed Khalid Mohammed Reda
Keyword(s):  
Direct Contact ◽  
High Salinity ◽  
Membrane Distillation ◽  
Feed Concentration ◽  
Modus Operandi ◽  
Brine Solution ◽  
Direct Contact Membrane Distillation ◽  
Flat Sheet ◽  
Plate Cell ◽  
Feed Temperature

Desalination is a process where fresh water produces from high salinity solutions, many ways used for this purpose and one of the most important processes is membrane distillation (MD). Direct contact membrane distillation (DCMD) can be considered as the most prominent type from MD types according to ease of design and modus operandi. This work studies the efficiency of using DCMD operation for desalination brine with different concentration (1.75, 3.5, 5 wt. % NaCl). Frame and plate cell was used with flat sheet PTFE hydrophobic type membrane. The study proves that MD is an effective process for desalination brines with feed temperature less than 60˚C especially for feed with low TDS. 37˚C, 47˚C, and 57˚C was feed temperature and 17, 22, 27˚C as permeate temperatures used in study, temperature in both sides of membrane are recorded and TDS for permeate collected to assure that there is no penetration of brine to permeate side, the results took every 30 min for time experiment of 180 min. From results, the flux increases with increasing feed temperature and flow rate, and decreasing with increasing feed concentration, experiment time, and permeate temperature.     

scholarly journals Seawater Desalination Based on a Bubbling and Vacuum-Enhanced Direct Contact Membrane Distillation

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guangfu Cao ◽  
Qingfen Ma ◽  
Jingru Li ◽  
Shenghui Wang ◽  
Chengpeng Wang ◽  
...  
Keyword(s):  
Production Rate ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Published Data ◽  
Water Production ◽  
Permeate Flux ◽  
Seawater Desalination ◽  
Noncondensable Gas ◽  
Direct Contact Membrane Distillation ◽  
Water Production Rate

A Bubbling and Vacuum-enhanced direct contact membrane distillation (BVDCMD) is proposed to improve the water production rate of the direct contact membrane distillation (DCMD-)based seawater desalination process. Its heat and mass transfer mechanism are theoretically analyzed, and a CFD model is established, which is verified by the published data. Four types of the noncondensable gas, “O2,” “air,” “N2,” and “H2,” are adopted as the bubbling gas, and their process enhancements under different pressure of permeate side, temperature, and NaCl concentration of feed side and flow velocities are investigated. The results show that the permeate flux increased remarkably with the decrease in the viscosity of the bubbling gas, and hence, “H2” is the best option for the bubbling gas, with the permeate flux being enhanced by 144.11% and the effective heat consumption being increased by 20.81% on average. The effective water production rate of BVDCMD is predicted to be 42.38% more than that of DCMD, proving its feasibility in the seawater desalination.

Innovative Diffusion Driven Desalination Process

2004 ◽  
Vol 126 (3) ◽  
pp. 219-225 ◽  
Author(s):  
James F. Klausner ◽  
Yi Li ◽  
Mohamed Darwish ◽  
Renwei Mei
Keyword(s):  
Fresh Water ◽  
Direct Contact ◽  
Production Efficiency ◽  
Waste Heat ◽  
Feed Water ◽  
Water Production ◽  
Vapor Mixture ◽  
Steam Power ◽  
Low Humidity ◽  
Feed Water Temperature

An innovative diffusion driven desalination (DDD) process is presented, and its performance based on thermodynamic considerations is thoroughly explored. The desalination is driven by water vapor saturating low humidity air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. The desalination process is suitable for operation at low temperatures and may be driven by waste heat with low exergy. It is demonstrated that the DDD process can yield a fresh water production efficiency of 4.5% with thermal energy consumption of 0.56 kWh per kilogram of fresh water production based on a feed water temperature of only 50°C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day.

Reverse osmosis brine treatment using direct contact membrane distillation: Effects of feed temperature and velocity

Desalination ◽  
2017 ◽  
Vol 423 ◽  
pp. 149-156 ◽  
Author(s):  
Zhongsen Yan ◽  
Haiyang Yang ◽  
Fangshu Qu ◽  
Huarong Yu ◽  
Heng Liang ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Direct Contact Membrane Distillation ◽  
Brine Treatment ◽  
Feed Temperature

Concentrating primary reverse osmosis concentrate by direct contact membrane distillation

2010 ◽  
Vol 10 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Dan Qu ◽  
Jun Wang ◽  
Deyin Hou ◽  
Zhaokun Luan ◽  
Baoqiang Wang
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Direct Contact ◽  
Tap Water ◽  
Membrane Distillation ◽  
Feed Water ◽  
Membrane Process ◽  
Direct Contact Membrane Distillation ◽  
Thermally Driven ◽  
Module Efficiency

In the present work, a thermally driven membrane process-direct contact membrane distillation was investigated for concentrating the primary reverse osmosis concentrate to minimize the water loss. The primary reverse osmosis concentrate used in the work was obtained from the RO process of the direct drinking water preparation system designed for the 29th Olympic Games with 50% recovery. The feed water was Beijing tap water. Membrane fouling during the DCMD process was discussed, and acidification and accelerated precipitation softening was used as the pretreatment method to control the calcium scaling. Experimental results showed that acidification can alleviate and even eliminate CaCO3 scaling, but CaSO4 crystallization still occurred and led to a sharp decline of module efficiency. Accelerated precipitation softening enabled a high removal efficiency of Ca2 + , so both the CaCO3 and CaSO4 scaling was efficiently controlled. After proper pretreatment to control calcium scaling, the primary reverse osmosis concentrate could be concentrated 40 times and then the whole recovery was enhanced to 98.8%.

The Effect of the Embedded Spacers on the Performance of Direct Contact Membrane Distillation System Operating With Different Inlet Feed Temperature

2019 ◽  
Author(s):  
Anas M. Alwatban ◽  
Ahmed M. Alshwairekh ◽  
Umar F. Alqsair ◽  
Robert Krysko ◽  
Abdullah A. Alghafis ◽  
...  
Keyword(s):  
Direct Contact ◽  
Membrane Distillation ◽  
Membrane Properties ◽  
Functional Surface ◽  
Feed Concentration ◽  
Turbulent Structures ◽  
Vapor Flux ◽  
Direct Contact Membrane Distillation ◽  
Dynamics Simulations ◽  
Feed Temperature

Abstract Computational fluid dynamics simulations are used to model the effect of the inlet feed temperature in direct contact membrane distillation modules. Embedded spacers are used as a local mixing promoter tool. Net-type spacers of angle 45° are used as spacers. The presence of the spacers will mitigate the temperature and concentration polarization effects. The calculation of the vapor flux through the membrane is based on the Dusty-Gas model. The membrane is considered as a functional surface, and the embedded spacers are treated as impermeable surfaces. The vapor flux equation couples the variation of the vapor flux in the feed and the permeate channel with the variation of the feed concentration along the membrane. The flow is considered turbulent in channels containing embedded spacers. The k–ω SST turbulent model is used to characterize the steady-state turbulent structures inside the flow channels. The flow rate in the feed and the permeate channels is fixed. The membrane properties are also fixed. The inlet feed temperature is varying while fixing the inlet permeate temperature. The results indicate that the embedded spacers increase the vapor flux permeation while the temperature and concentration polarizations are mitigated. As the inlet feed temperature is increased, the effect of the embedded spacers becomes more significant.

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