Afsari Morteza, Ghorbani Amir Hossein, Asghari Morteza, Shon Ho Kyong, Tijing Leonard D
Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, PO Box 123, 15 Broadway, Ultimo, New South Wales, 2007, Australia.
Chemical Engineering Department, Tarbiat Modarres University, Tehran, P.O. Box 14115-143, Tehran, Iran.
Chemosphere. 2022 Oct;305:135294. doi: 10.1016/j.chemosphere.2022.135294. Epub 2022 Jun 10.
In this study, a comprehensive model was developed using Computational Fluid Dynamics (CFD), and the behaviour of a direct contact membrane distillation (DCMD) system was investigated at hypersaline feedwater conditions. The effects of various operating parameters including feed and permeate velocities, temperatures and salinities, as well as different membrane characteristics like thickness, porosity, and thermal conductivity were studied. The developed simulation model was also validated using experimental data. The results showed that the membrane conductivity and thickness had a significant impact on the DCMD performance, and the optimum operational condition was necessary to be determined. The results showed that increasing the feedwater salinity from 50 to 200 g/l decreased the membrane flux by up to 33%, while a four times decrease in thermal conductivity of the membrane could lead to an increase in the membrane flux from 11.2 to 32.4 l/m·h (LMH). In addition, the optimal membrane thickness was found to increase with salinity, reaching >120 μm for treatment of 22 wt% NaCl feedwater solution. However, the flux declined from >32 LMH to <13 LMH upon the increase in feedwater salinity (up to 22 wt% NaCl solution). It is also shown that a thinner membrane performed better for desalination of low salinity feedwater, while the thicker one produces higher separation performance and thermal efficiency for hypersaline brine desalination.
在本研究中，利用计算流体动力学（CFD）开发了一个综合模型，并研究了在高盐度进水条件下直接接触膜蒸馏（DCMD）系统的行为。研究了各种操作参数的影响，包括进料和渗透速度、温度和盐度，以及不同的膜特性，如厚度、孔隙率和热导率。所开发的模拟模型也通过实验数据进行了验证。结果表明，膜的电导率和厚度对DCMD性能有显著影响，需要确定最佳操作条件。结果表明，将进水盐度从50 g/l提高到200 g/l可使膜通量降低高达33%，而膜的热导率降低四倍可导致膜通量从11.2 l/m·h（LMH）增加到32.4 l/m·h（LMH）。此外，发现最佳膜厚度随盐度增加，对于22 wt% NaCl进水溶液的处理，膜厚度达到>120μm。然而，随着进水盐度增加（高达22 wt% NaCl溶液），通量从>32 LMH下降到<13 LMH。研究还表明，较薄的膜对低盐度进水的脱盐效果更好，而较厚的膜对高盐度盐水脱盐具有更高的分离性能和热效率。
