Produced Water Desalination via Pervaporative Distillation

Jingbo Wang,Subir Bhattacharjee,David Jassby,Arian Edalat,Dian Tanuwidjaja,Eric M V Hoek

doi:10.3390/w12123560

Abstract

Herein, we report on the performance of a hybrid organic-ceramic hydrophilic pervaporation membrane applied in a vacuum membrane distillation operating mode to desalinate laboratory prepared saline waters and a hypersaline water modeled after a real oil and gas produced water. The rational for performing “pervaporative distillation” is that highly contaminated waters like produced water, reverse osmosis concentrates and industrial have high potential to foul and scale membranes, and for traditional porous membrane distillation membranes they can suffer pore-wetting and complete salt passage. In most of these processes, the hard to treat feed water is commonly softened and filtered prior to a desalination process. This study evaluates pervaporative distillation performance treating: (1) NaCl solutions from 10 to 240 g/L at crossflow Reynolds numbers from 300 to 4800 and feed-temperatures from 60 to 85 °C and (2) a real produced water composition chemically softened to reduce its high-scale forming mineral content. The pervaporative distillation process proved highly-effective at desalting all feed streams, consistently delivering <10 mg/L of dissolved solids in product water under all operating condition tested with reasonably high permeate fluxes (up to 23 LMH) at optimized operating conditions.

Highlights

Pervaporation (PV) is a hybrid distillation process whereby separation performance is a function of the relative solubilities of the constituents in the feed as well as their relative boiling points
A higher water flux was expected at a higher temperature, because the partial vapor momentary free volumes are created by the thermal motion of polymer chains in an amorphous pressure difference between the feed and permeate side, which is the driving force of a pervaporative desalination (PVD) process, is region; as the temperature increased, the free volume of the membranes could increase the strongly affected by temperature
99.86% 2400 under all the tested operating conditions, which is similar to the typical rejections in conventional vacuum MD (VMD) processes [28

Summary

Introduction

Pervaporation (PV) is a hybrid distillation process whereby separation performance is a function of the relative solubilities (in the membrane) of the constituents in the feed as well as their relative boiling points. While PV has found limited practical application in water desalination to date, pervaporative desalination (PVD) has been studied for over 25 years [7,8]. Other studies explored different types of polymeric and mixed matrix membranes applied to PVD [15,16,17,18,19,20]. Several earlier studies have explored the PVD process and even solar powered PVD [21,22,23].

Methods

Results

Conclusion