Showerhead feed distribution for optimized performance of large scale membrane distillation modules

Soukane, Sofiane; Ghaffour, NorEddine

Showerhead feed distribution for optimized performance of large scale membrane distillation modules

Files

SS_Showerhead JMD online version.pdf (2.56 MB)

Embargo End Date

2022-08-28

Type

Article

Authors

Soukane, Sofiane

Ghaffour, NorEddine

KAUST Department

King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological & Environmental Science & Engineering (BESE), 23955-6900, Thuwal, Saudi Arabia.
Environmental Science and Engineering Program
Biological and Environmental Sciences and Engineering (BESE) Division

Online Publication Date

2020-08-28

Print Publication Date

2021-01

Date

2020-08-28

Submitted Date

2020-05-16

Abstract

The outstanding capabilities of membrane distillation (MD) process to handle highly saline solutions are still driving research efforts to take this process to the industrial level. MD scale-up remains a challenge as the objective of increasing performance faces several design issues imposed by intrinsic physical constraints. Among the major hurdles encountered with an increase in membrane active area stands temperature polarization, a phenomenon that drastically penalizes MD efficiency. It is shown that in a typical permeate flux distribution over the membrane of an MD module, the highest local permeate flux values contribute to less than 1% of the total module production, while average values add up to half the production, suggesting a dramatic underuse of the membrane active area. Therefore, this investigation explores design opportunities to enhance module performance by reducing polarization for large-scale modules. Using state of the art CFD calculations, it is shown that combined lateral flow and progressive feeding from perforated top wall of the feed channel, and eventually the permeate channel in case of direct contact membrane distillation (DCMD) variant, can considerably increase the productivity of the module. Results further confirm the critical importance of flow distribution at the vicinity of the membrane and its effect on permeate flux. Careful analysis reveals that there is an optimum flow rate ratio between the two feed paths and that the design of the holes of the perforated plate plays a critical role to ensure flow smoothness and reduce temperature polarization. Simulations show that the productivity of a 1 m2 flat sheet module can be enhanced by more than 50% under the same operating conditions, which opens up new opportunities for MD scale up.

Citation

Soukane, S., & Ghaffour, N. (2020). Showerhead feed distribution for optimized performance of large scale membrane distillation modules. Journal of Membrane Science, 118664. doi:10.1016/j.memsci.2020.118664

Acknowledgements

The research reported in this paper was supported by King Abdullah University of Science and Technology (KAUST), Saudi Arabia. The authors acknowledge help, assistance and support from the Water Desalination and Reuse Center (WDRC). Fig. 5 (also used as Graphical Abstract) was produced by Xavier Pita, scientific illustrator at KAUST.