Development of mass and heat transfer coupled model of hollow fiber membrane for salt recovery from brine via osmotic membrane distillation

Sher Ahmad,Sarah Farrukh,Gabriela Vollet Marson,Mohammad Younas,Mashallah Rezakazemi,Waheed Ur Rehman

doi:10.1186/s12302-021-00520-z

Abstract

BackgroundIn this research work, a coupled heat and mass transfer model was developed for salt recovery from concentrated brine water through an osmotic membrane distillation (OMD) process in a hollow fiber membrane contactor (HFMC).The model was built based on the resistance-in-series concept for water transport across the hydrophobic membrane. The model was adopted to incorporate the effects of polarization layers such as temperature and concentration polarization, as well as viscosity changes during concentration.ResultsThe modeling equations were numerically simulated in MATLAB® and were successfully validated with experimental data from literature with a deviation within the range of 1–5%. The model was then applied to study the effects of key process parameters like feed concentrations, osmotic solution concentration, feed, and osmotic solution flow rates and feed temperature on the overall heat and mass transfer coefficient as well as on water transport flux to improve the process efficiency. The mass balance modeling was applied to calculate the membrane area based on the simulated mass transfer coefficient. Finally, a scale-up for the MD process for salt recovery on an industrial scale was proposed.ConclusionsThis study highlights the effect of key parameters for salt recovery from wastewater using the membrane distillation process. Further, the applicability of the OMD process for salt recovery on large scale was investigated. Sensitivity analysis was performed to identify the key parameters. From the results of this study, it is concluded that the OMD process can be promising in salt recovery from wastewater.

Highlights

Industrial wastewater effluents contain a large variety of useful chemical compounds
The model was applied to study the effect of main parameters like feed and osmotic solution flow rates, feed temperature, the effect of the hydrodynamic boundary layer as well as temperature and concentration polarization on transmembrane water transport flux
In this research work, the osmotic membrane distillation (OMD) process was studied through modeling and simulation to recover concentrated Na2CO3 from wastewater using an aqueous solution of NaCl as the osmotic solution

Summary

Conclusions

The OMD process was studied through modeling and simulation to recover concentrated Na2CO3 from wastewater using an aqueous solution of NaCl as the osmotic solution. The model was validated with experimental results from the literature [25] and was applied to study the effect of different parameters on water flux. For both cases (feed and osmotic solution concentration runs), simulation results were in good agreement with the experimental results with a maximum deviation of 7%. The water transport flux was enhanced when the feed flow rate was increased from 1.2 to 3 L h −1 and the temperature was increased from 293 to 313 K. The scaling up of the OMD for salt concentration was proposed, and the required area was estimated for industrial flow rates. For continuous operation, a reservoir is required for the removal of salt

Introduction

Results and discussion