HOLLOW-FIBRE MEMBRANE DISTILLATION & MEMBRANE STRIPPING

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2 DEPARTMENT GREEN CHEMISTRY RESEARCH GROUP PAINT (PARTICLE AND INTERFACIAL TECHNOLOGY) HOLLOW-FIBRE MEMBRANE DISTILLATION & MEMBRANE STRIPPING Membranes & modules with improved efficiency, integrity and fouling-resistance

3 INTRODUCTION & APPLICATIONS 3

4 PARTICLE & INTERFACIAL TECHNOLOGY GROUP ~ 25 people 4 post-docs, 17 PhD-students Chair Industrial & Circular Water Treatment CAPTURE 4

5 MEMBRANE DISTILLATION Hydrophobic membranes Different configurations Mostly flat sheet membranes Mainly for water transfer 5

6 MEMBRANE STRIPPING T T ph Hydrophobic membranes p NH3 is governed by: - Henry coefficient - NH 3 /NH 4 + equilibrium ph & T control is vital Transfer driven by ph (and/or T, typically without gradient) Transfer of volatile species (e.g., NH 3 ) 6

7 APPLICATIONS Membrane distillation: (T-gradient, up to C) Desalination (high recoveries, pure permeate) Dewatering (e.g., of highly concentrated brines) Applications ranging from food to petrochem Aquastill Membrane stripping: Extraction and recovery of ammonia Extraction of bio-based products (e.g., low-molecular weight aroma s, organic acids,...) Aquaver 7 Bluetec

8 CURRENT HURDLES FOR MD AND MS 8

9 CURRENT DRAWBACKS Membrane distillation: Modules still expensive, high capital cost Module integrity questionable under thermal stress Module water recovery typically low (<5%) -> staging & CAPEX Module thermal efficiency rather low Hydrophobic membranes susceptible to fouling & wetting Membrane stripping: Hydrophobic membranes susceptible to fouling & wetting Mass transfer in commercial modules can be improved Structural integrity of commercial modules should be improved Up-scaling challenging (insufficient knowledge on stacking and staging) -> Need for improved module design (and potting/glueing) 9

10 PROJECT GOALS 10

11 PROJECT GOALS 1) Upscaling of current hollow fibre/tubular MS for NH 3 recovery: Concept feasible on m³/h scale Up-scaling to 20 m³/h via improved staging & module design 2) Development of novel tubular/hollow fibre membranes and modules for MD and MS: Improved process performance Use of novel design and hollow fibre membranes Advantages of hollow fibre membranes: potting) - one design for all MD/MS configurations - structural performance improves module intregrity (less glue lines/better 11

12 APPROACH 12

13 TWO-STAGED APPROACH PART 1: upscaling of current hollow-fibre/tubular MS modules PART 2: development of novel, robust hollow fibre modules with hydrophilic/omniphobic membranes for improved efficiency, integrity and fouling resistance 13

14 PART 1: UPSCALING OF NH 3 STRIPPING Pilot trials have been run up to 2 m³/h Large potential for NH 3 stripping on digesters & chemical waste streams (Bluetec) Use of commercial membranes Questions for scale-up: Optimal fibre diameter to improve mass transfer and avoid pressure build-up Fouling/wetting on the long term? Module stacking/installation design (via modelling) 14

15 PART 2: NOVEL MEMBRANE & MODULE DEVELOPMENT Hydrophilic & omniphobic top layers on hydrophobic support: Plasma treatment vs coating (VITO & UGent developments) Improved potting/glueing Improved fouling resistance & higher fluxes Different hollow fibre module types: Different inner & outer diameters Outside-in vs inside out mode Improved mass & heat transfer through modelling Lower module complexity & opportunities for patenting 15

16 PART 2: NOVEL MEMBRANE & MODULE DEVELOPMENT Increased dewatering factors via MD+: Lower energy consumption & increased dewater (TNO development) At least two-fold energy consumption compared to current MD Water recoveries of 20-50% in single membrane module Improved module ingtergrity Applications: NH 3 stripping in challenging applications (e.g., petrochem) Challenging streams for dewatering 16

17 INDUSTRIAL CONSORTIUM 17

18 PARTIES THAT HAVE SHOWN INTEREST: Industrial: balance between MS and MD applications: Yara OCI nitrogen Akzo-Nobel DOW Evides... Implementation: Bluetec (Lex van Dijk) Research: VITO TNO Ghent University 18

19 Arne Verliefde Professor, Ghent Universty PARTICLE AND INTERFACIAL TECHNOLOGY GROUP (PAINT) E arne.verliefde@ugent.be T Ghent Ghent University