Study of mass transfer coefficient in membrane desalination

Cai, Jingcheng; Guo, Fei

doi:10.1016/j.desal.2016.12.013

Cited by 46 publications

(25 citation statements)

References 29 publications

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“…The pressure increased until it exceeded the critical pressure that prevents the liquid from wetting the membrane pores. The detailed LEP tests were described in previous studies [ 22 , 35 ]. As shown in Figure 1 b, the LEP value of the PTFE membrane used in this work is ~ 650 kPa, which meets the requirements of MD experiments conducted here.…”

Section: Methodsmentioning

confidence: 99%

Mass Transfer Analysis of Air-Cooled Membrane Distillation Configuration for Desalination

2021

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It has been proposed that the air-cooled configuration for air gap membrane distillation is an effective way to simplify the system design and energy source requirement. This offers potential for the practical applications of membrane distillation on an industrial scale. In this work, membrane distillation tests were performed using a typical water-cooled membrane distillation (WCMD) configuration and an air-cooled membrane distillation (ACMD) configuration with various condensing plates and operating conditions. To increase the permeate flux of an ACMD system, the condensing plate in the permeate side should transfer heat to the atmosphere more effectively, such as using a more thermally conductive plate, adding fins, or introducing forced convection air flow. Importantly, a practical mass transfer model was proposed to describe the ACMD performance in terms of permeate flux. This model can be simplified by introducing specific correction values to the mass transfer coefficient of a WCMD process under the same conditions. The two factors relate to the capacity (B) and the efficiency (σ), which can be considered as the characteristic factors of a membrane distillation (MD) system. The experimental results are consistent with the theoretical estimations based on this model, which can be used to describe the performance of an MD process.

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Section: Methodsmentioning

confidence: 99%

Mass Transfer Analysis of Air-Cooled Membrane Distillation Configuration for Desalination

2021

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“…The MD tests were conducted based on an air-gap membrane distillation (AGMD) system described in detail in the previous studies [ 17 , 47 ]. CuSO 4 solution (3.5 wt.%, blue color) was used as the feed.…”

Section: Methodsmentioning

confidence: 99%

“…The contact angle tests were repeated 10 times. The LEP tests were carried out with an upgraded unit (see Figure 2) from references [18,47]. The membrane was placed in a stainless steel holder with an effective diameter of 9 mm.…”

Section: Membrane Characterizationmentioning

confidence: 99%

Transport Analysis of Anti-Wetting Composite Fibrous Membranes for Membrane Distillation

2020

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Composite electrospun fibrous membranes are widely studied for the application of membrane distillation. It is an effective approach to enhance the membrane distillation performance in terms of anti-wetting surface and permeate flux by fabricating composite fibrous membranes (CFMs) with a thin skin layer on a thick supporting layer. In this work, various membranes prepared with different pore sizes and porosities by polyacrylonitrile and polyvinylpyrrolidone were prepared. The membrane characteristics and membrane distillation performance were tested. The mass transfer across the membranes was analyzed experimentally and theoretically in detail. It is shown that the skin layer significantly increases liquid entry pressure of the CFM by 5 times. All the membranes have a similar permeate flux. The permeate flux of membranes is stable at 19.2 ± 1.2 kg/m2/h, and the salt rejection ratios remain above 99.98% at 78 ± 1 °C for 11 h. The pore size and porosity of membranes have an insignificant effect on the temperature distribution of membrane. The porosity and pore size of the skin layer have an insignificant effect on the mass transfer process of the CFM. The mass transfer process of the CFM is governed by the supporting layer.

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“…Mass transfer in the AGMD process has been described mainly by two mathematical models: the Fickian model based on binary diffusion 8,10,[34][35][36][37][38][39] and the Stefan-Maxwell model based on multicomponent diffusion. [23][24][25]37 The Stefan-Maxwell model has two types of solution method: exact matrix 40 and approximate solutions.…”

Section: Mathematical Modelling Of Agmdmentioning

confidence: 99%

Experimental and mathematical study of air gap membrane distillation for aqueous HCl azeotropic separation

Kalla

Upadhyaya

Singh

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND In the present study, the feasibility of air gap membrane distillation (AGMD) process is investigated for breaking an azeotropic mixture. A test cell AGMD module with hydrophobic PTFE membrane was fabricated and HCl/H2O azeotrope (20.2 wt% HCl) was taken as feed. A mathematical model based on Stefan diffusion multicomponent molecular‐Knudsen mass transfer approach has been developed and validated with experimental data. The effects of different process parameters on total permeate flux, on selectivity and on breaking an HCl/H2O azeotrope mixture also have been studied. The feed side membrane surface temperature and membrane side condensing surface temperature were estimated by CFD modelling. RESULTS The HCl selectivity obtained in the permeate was <1, which indicates that permeate flux is leveraged with water and a higher HCl concentration in the retentate was achieved relative to the permeate. The permeate flux decreased from 36 to 17 kg m−2 h−1 upon increasing the air gap from 3 mm to 11 mm at 50 °C feed temperature. The permeate flux increased from 4 to 28.5 kg m−2 h−1 upon increasing the feed temperature from 30 to 50 °C at 5 mm air gap. CONCLUSION With azeotropic feed, the maximum concentration of HCl achieved in the retentate was 30.8 wt% HCl (i.e. a hyperazeotropic solution) and in permeate was found to be 15.29 wt% HCl (i.e. hypoazeotropic solution). This indicates a strong possibility of using AGMD for azeotropic mixture separation. It also was observed that the permeate flux is affected mainly by feed temperature and air gap width. © 2018 Society of Chemical Industry

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Study of mass transfer coefficient in membrane desalination

Cited by 46 publications

References 29 publications

Mass Transfer Analysis of Air-Cooled Membrane Distillation Configuration for Desalination

Mass Transfer Analysis of Air-Cooled Membrane Distillation Configuration for Desalination

Transport Analysis of Anti-Wetting Composite Fibrous Membranes for Membrane Distillation

Experimental and mathematical study of air gap membrane distillation for aqueous HCl azeotropic separation

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