These slides use concepts (e.g., scaling) from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze how membranes have and are becoming more economically feasible for one application, pervaporation. The economic feasibility of pervaporation is improved as temperatures and pressures of the systems are increased, which are facilitated by larger scale, and as the membranes are improved. Membranes become cheaper as they are made thinner (example of scaling) and they become better as the pore size is made both smaller and is designed for allowing specific molecules to pass through the pores.

1. PERVAPORATION
MT5009 Analyzing Hi-Tech Opportunities
Semester 2, 2011/2012
See Siew Hui A0077625X
Too Kim Hui A0077025J
Hubert Giam A0082070R
Chua Wei Sun A0082022X
Damien Poh Weiye A0076856M
Linda Wibisono A0077098N

2. Overview
1) Intro
 Distillation and its disadvantage
 What is pervaporation?
 Applications of pervaporation
2) Pervaporation Performance Parameters
 Selectivity
 Flux
 Membrane Thickness
 Temperature
 Kinetic diameter
3) Improvements
4) Hybrid Process (Distillation and Pervaporation)
5) Potential Business Opportunities

3. Drawbacks of the Existing Method (Distillation)
 Distillation is a conventional liquid mixture separation technology
based on their boiling points.
 Disadvantages of distillation
 Difficult to separate liquids mixtures which the components have similar boiling
point (azeotropes).
 Advance in technology - Pervaporation can be used for breaking
azeotropes.

4. Pervaporation
 Pervaporation is the separation of liquid mixtures by partial
vaporization through a membrane.
Key component in
Pervaporation
Feed
membrane

5. Major Advantage of Pervaporation
Distillation has major disadvantage compared to the new method of Pervaporation.
Distillation is a very energy consuming process (heating process).
Source: Trends in Research and Development of Nanoporous Ceramic Separation Membranes, 2009

6. Applications of Pervaporation
 Applications include:
 Environmental application: Removing organic solvents from industrial
waste waters.
 Pollution control: Removal of small quantities of VOCs (Volatile organic
compounds) from contaminated water
 Chemical Industry: removal of water from organic solvents and solvents
mixtures – to obtain pure organic solvents
 Pervaporation is a very mild process and hence very effective for separation
of those mixtures which can not survive the harsh conditions of distillation.

7. Overview
1) Intro
 Distillation and its disadvantage
 What is pervaporation?
 Applications of pervaporation
2) Pervaporation Performance Parameters
 Selectivity
 Flux
 Membrane Thickness
 Temperature
 Kinetic diameter
3) Improvements
4) Hybrid Process (Distillation and Pervaporation)
5) Potential Business Opportunities

8. Measured Performance Parameters
Some of the most important parameters used to assess the pervaporation process are:
1. Membrane selectivity : what goes through and what gets rejected
2. Flux: Denote the amount of output (measured in relation to membrane area , thickness and
time).
What will influence the performance?
1. Feed temperature: Refers to temperature of the feed stock or any other representative between
feed and retentate streams.
2. Membrane thickness: Refers to dry thickness.
3. Kinetic diameter: diameter of pore needed to let a specific molecule pass

9. Performance Parameters - Selectivity
 Membrane selectivity allows us to choose certain
molecules to pass through the membrane
 Improved membrane selectivity will increase absorption
rates
 more efficient and possible cost reduction
 This can be achieved by better understanding of the
material selected for the membrane

10. Impact of Feed Temperature on Flux
 Feed Temperature
 Molecules movement increases exponentially with temperature
 improve flux rate

11. Impact of Membrane Thickness on Flux
The thinner the
membrane, the faster
the flux

12. Influencing Parameters – Kinetic Diameter (1)
Kinetic diameter can be understood as the diameter of a pore needed to let that
specific molecule pass
Source: Fundamentals and applications of pervaporation through Zeolite membranes, 2004

13. Influencing Parameters – Kinetic Diameter (2)
Source: Fundamentals and applications of pervaporation through Zeolite membranes, 2004

14. Overview
1) Intro
 Distillation and its disadvantage
 What is pervaporation?
 Applications of pervaporation
2) Pervaporation Performance Parameters
 Selectivity
 Flux
 Membrane Thickness
 Temperature
 Kinetic diameter
3) Improvements
4) Hybrid Process (Distillation and Pervaporation)
5) Potential Business Opportunities

15. Key Cost Components For Pervaporation
• The operating cost of pervaporation is heavily reliant on the cost of
generating heat and the cost of the membrane used
• Current trend: decreasing heating cost and decreasing membrane cost
Source: http://www.scielo.org.ar/scielo.php?pid=S0327-07932003000200018&script=sci_arttext&tlng=en

16. Decreasing Trend in Membrane Cost from 1989 to 2000
Reasons of decreasing membrane cost:
1. Membrane surface area per module increase  lesser membrane modules to produce the same
amount of output
2. Membrane mass production  production cost decrease
3. More compact module  cost savings in civil works
Source: J.-M. Laine, D. Vial, Pierre Moulart, Status after 10 years of operation – overview of UF technology today, Desalination
131 (2000) 17-25

17. Similar Decreasing Trend in Membrane Cost from 1970 to 2010
Source: American Membrane Technology Association (AMTA), www.amtaorg.com

18. Improvement in cost of heat generation
-Cost of Conserved Energy (CCE) summarizes annual costs associated
with saving a GJ (approximately 0.95 MBtu) of energy with a particular
measure.
-Table shows that energy efficient measures lead to energy savings that
have short payback periods from immediate to 2.7 years.
-Industry is looking towards reducing cost of heat generation

19. Improvements in membrane
1) Membrane preparation methods  more methods are developed to
prepare membranes with different structures for different application
 Phase separation method developed in 1960
 Scanning Electron Microscope became available in 1960  helped in
the detailed study of the membrane structure
2) Membrane selective layer is getting thinner over 30 years
0.2 – 0.4 µm  <0.1 µm  0.05 µm (only in lab)
3) In 30 years membrane flux and selectivity improved by 10 times, e.g.
selectivity factor from 8 to 80.

20. How to control pore size?
 Methods used to create pores on membrane surface:
 Sintering
 Stretching
 Casting
 Leaching
 Nucleation-track
 Gelation by water vapor
 Variables that affect pore size:
 Membrane materials
 Different solvents used and concentration in the casting
solution
 Temperature of the casting solution

21. Overview
1) Intro
 Distillation and its disadvantage
 What is pervaporation?
 Applications of pervaporation
2) Pervaporation Performance Parameters
 Selectivity
 Flux
 Membrane Thickness
 Temperature
 Kinetic diameter
3) Improvements
4) Hybrid Process (Distillation and Pervaporation)
5) Potential Business Opportunities

22. Conventional Process – Distillation
Eliminate:
i) heating process
ii) use of benzene
Heater

23. Hybrid Process
(Distillation & Pervaporation)
Distillation Pervaporation

24. Lower Cost of Hybrid Process
140
€130 / ton
120
- 45%
100
Total Cost (€/ton product)
80
€72 / ton
60
40
20
0
Distillation Distillation - Pervaporation
Maintenance Cost 15.11 12.45
Investment Cost 78.28 42.16
Operation Cost 36.65 17.25
Source: Economic comparison between azeotropic distillation and different hybrid systems combining distillation with pervaporation
for the dehydration of isopropanol, Elsevier, 2004

25. Overview
1) Intro
 Distillation and its disadvantage
 What is pervaporation?
 Applications of pervaporation
2) Pervaporation Performance Parameters
 Selectivity
 Flux
 Membrane Thickness
 Temperature
 Kinetic diameter
3) Improvements
4) Hybrid Process (Distillation and Pervaporation)
5) Potential Business Opportunities

26. Opportunity for Material Supplier
1) Chitosan membranes
 “Natural membrane”, i.e. without chemical /toxic cross-linkers
 Used in biotechnology applications, e.g. entrap drugs, bioactive
ingredients, enzyme immobilization
2) Zeolite membranes
 Higher flux
 Higher output

27. Improvement with Zeolite membrane
Higher flux with
Zeolite Membrane
Conventional
Polymer Membrane
Higher output with
Membrane Type Feed Output Zeolite Membrane
Polymer 99.59% IPA
83% IPA 0.41% Water
Zeolite 17% Water 99.68% IPA
0.32% Water
Source: Economic comparison between azeotropic distillation and different hybrid systems combining distillation with pervaporation
for the dehydration of isopropanol, Elsevier, 2004

28. Opportunities for IT
Diffusion of computer programs for selection of Zeolite
membrane composition from databases

29. Opportunities for Pervaporation System
Suppliers
Huge market of the separation in the future
Huge business opportunity to introduce pervaporation to these plants

30. Others Opportunities
1) For companies dealing with green energy (can recover biofuels from
fermentation broths)
2) For companies dealing with other membrane-property separations
 Gas separation

31. THANK YOU!

32. Appendix

33. Pervaporation
Advantages Drawbacks
• Low energy consumption. • Scarce membrane market.
• Low investment cost. • Lack of information.
• Better selectivity without thermodynamic • Low permeate flows.
limitations. • Better selectivity without thermodynamic
• Clean and close operation. limitations.
• No process wastes. • Limited applications:
• Compact and scalable units. • Organic substances dehydration.
• Recovery of volatile compounds at low
concentrations.
• Separation of azeotropic mixtures.
23

34. Summary (2)
Membranes: Composite membranes with an
elastomeric or glassy polymeric top layer.
Thickness:  0.1 to few m (for top layer)
Pore size: Non-porous
Driven force: Partial vapor pressure or activity
difference.
Separation principle: Solution/Diffusion
Membrane material: Elastomeric and glassy.
Applications:  Dehydration of organic solvents.
 Removal of organic compounds from
water.
 Polar/non-polar.
 Saturated/unsaturated.
 Separation of isomers.
24

35. Zeolite Synthesis – A Summary
Synthesis by Hydrothermal process involving
1) crystallization of a zeolite layer onto a
porous support
2) from a gel that is usually composed of
water, amorphous silica, a source for
tetrahedral framework atoms other than
Si, a structure directing organic template,
and sometimes a mineralizing agent
3) Difference in synthesis time, temperature,
gel composition for crystallization results
in different types of Zeolite formation