Flux enhancement in membrane distillation by fabrication of dual layer hydrophilic–hydrophobic hollow fiber membranes

Bonyadi, Sina; Chung, Tai‐Shung

doi:10.1016/j.memsci.2007.08.034

Cited by 330 publications

(186 citation statements)

References 37 publications

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“…Thus, DCMD performance relies on the complex relationships between simultaneous heat and mass transfers, which are in the same direction from the feed side to the permeate side. Assuming no heat loss through module walls, the total heat flux can be expressed as [15,16]:…”

Section: Heat Transfermentioning

confidence: 99%

“…(1), λ(T 1 -T 2 ) is the sensible heat transfer across the membrane and H latent N is the latent heat transfer. The heat conduction coefficient λ can be calculated as [15,16] (1 ) solid air λ ε λ ελ…”

Section: Heat Transfermentioning

confidence: 99%

“…The flux should change with temperature exponentially, because vapour pressure is an exponential function of temperature [18]. According to [9,15], it can be estimated as…”

Section: Mass Transfermentioning

confidence: 99%

See 2 more Smart Citations

Identification of material and physical features of membrane distillation membranes for high performance desalination

Zhang

Dow

Duke

et al. 2010

Journal of Membrane Science

254

156

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In this paper, the performance of various membranes were assessed in direct contact membrane distillation (DCMD) under different feed velocities and inlet temperatures. The membranes studied included a polyvinylidenefluoride (PVDF) microfiltration membrane with a non-woven support layer, a polytetrafluoroethylene (PTFE) microfiltration membrane with a non-woven support layer, and three MD membranes made from PTFE of different pore size and all with a structured scrim support layer. The results showed that distillation using PTFE membranes produced much higher flux than that of the PVDF microfiltration membrane at the same operational conditions, and the support layer affected not only the flux, but also the energy efficiency (0.51 -0.24). The results also show that increasing the velocity of the feed and its inlet temperature increased the flux, but the rate of flux increase diminishes at high velocities. The mass transfer coefficient improved for thinner support and active layer membranes, leading to fluxes as high as 46 L.m -2 h -1 at 80˚C. The heat transfer characteristics were found to be superior for the open scrim backed membranes compared to the non-woven support membranes, resulting in significantly greater thermal efficiency for the scrim backed membranes.

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Section: Heat Transfermentioning

confidence: 99%

Section: Heat Transfermentioning

confidence: 99%

See 1 more Smart Citation

Identification of material and physical features of membrane distillation membranes for high performance desalination

Zhang

Dow

Duke

et al. 2010

Journal of Membrane Science

254

156

View full text Add to dashboard Cite

show abstract

“…Assuming no heat loss through module walls, the total heat flux can be expressed as [4,10,11]: In this paper, a high-flux asymmetrically-structured hollow fibre module was tested and its structure used to explain flux variations resulting from changes in MD configuration. Table 2 lists the characteristics of the membranes as specified by the supplier and the dimension of the module used in the experiments.…”

Section: Heat Transfermentioning

confidence: 99%

“…From Figure 1, we observe that it is easier to put more effective area into the hollow fibre module with less restriction than that of the flat sheet module, however, turbulence promoters are likely to be required to reduce temperature polarisation. One of the main impediments of the hollow fibre module is its typically low flux, which is generally 1-4 L.m -2 h -1 at 40-60°C [4][5][6]. This is much lower than that of the flat sheet membranes with fluxes of 20-30 L.m -2 h -1 [7].…”

Section: Introductionmentioning

confidence: 99%

Performance of asymmetric hollow fibre membranes in membrane distillation under various configurations and vacuum enhancement

Zhang

Duke

et al. 2010

Journal of Membrane Science

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Hollow fibre membrane distillation (MD) modules have a more compact structure than flat sheet membrane modules, providing potentially greater advantage in commercial applications. In this paper, a high-flux asymmetrically-structured hollow fibre MD module was tested under various conditions. The results show that increasing velocity and temperature are positive for flux, and salt rejection was more than 99% over the entire experimental range. The hollow fibre module also showed great variation in flux when altering the hot feed flow from the lumen side to the shell side of the fibre, and this phenomenon was analysed based on the characterisation of the asymmetric structure of the hollow fibre. The largest mass transfer resistance was determined to be in the small pore size skin layer on the outer surface of the membrane, and having the hot feed closest to this surface provided the greatest vapour pressure difference across this high resistance mass transfer layer. The results also show that placing the suction pump on the permeate outlet increased the flux by lowering the pressure within the pore and hence increased the rate of vapour mass diffusion. A maximum flux of 19 Lm -2 h -1 was obtained at 85˚C when hot feed was entering the shell side, and the mass transfer coefficient was relatively constant across the entire temperature range when operated at high velocities. These outcomes suggest that asymmetric hollow fibre MD modules should be operated with hot brine feed closest to the high resistant skin layer, and that vacuum enhanced MD further increases vapour transport and flux.

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Membrane Distillation

Baghbanzadeh

Lan

Rana

et al. 2016

Nanostructured Polymer Membranes

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Flux enhancement in membrane distillation by fabrication of dual layer hydrophilic–hydrophobic hollow fiber membranes

Cited by 330 publications

References 37 publications

Identification of material and physical features of membrane distillation membranes for high performance desalination

Identification of material and physical features of membrane distillation membranes for high performance desalination

Performance of asymmetric hollow fibre membranes in membrane distillation under various configurations and vacuum enhancement

Membrane Distillation

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