PERVAPORATION

See Siew Hui A0077625X

Too Kim Hui A0077025J

Hubert Giam A0082070R

Chua Wei Sun A0082022X

Damien Poh Weiye A0076856M

Linda Wibisono A0077098N

MT5009 Analyzing Hi-Tech OpportunitiesSemester 2, 2011/2012

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

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.

Pervaporation

Pervaporation is the separation of liquid mixtures by partial

vaporization through a membrane.

membrane

Key component in

Pervaporation Feed

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

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.

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

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

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

Performance Parameters - Selectivity

Feed Temperature

Molecules movement increases exponentially with temperature

improve flux rate

Impact of Feed Temperature on Flux

Impact of Membrane Thickness on Flux

The thinner the

membrane, the faster

the flux

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

Influencing Parameters – Kinetic Diameter (2)

Source: Fundamentals and applications of pervaporation through Zeolite membranes, 2004

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

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

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

Source: American Membrane Technology Association (AMTA), www.amtaorg.com

Similar Decreasing Trend in Membrane Cost from 1970 to 2010

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

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.

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

How to control pore size?

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

Conventional Process – Distillation

Eliminate:

i) heating process

ii) use of benzene

Heater

Distillation Pervaporation

Hybrid Process

(Distillation & Pervaporation)

Lower Cost of Hybrid Process

Distillation Distillation - Pervaporation

Maintenance Cost 15.11 12.45

Investment Cost 78.28 42.16

Operation Cost 36.65 17.25

0

20

40

60

80

100

120

140

To

tal C

ost

(€/t

on

pro

du

ct)

- 45%

€130 / ton

€72 / ton

Source: Economic comparison between azeotropic distillation and different hybrid systems combining distillation with pervaporation

for the dehydration of isopropanol, Elsevier, 2004

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

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

Opportunity for Material Supplier

Improvement with Zeolite membrane

Higher flux with

Zeolite Membrane

Membrane Type Feed Output

Polymer

83% IPA

17% Water

99.59% IPA

0.41% Water

Zeolite 99.68% IPA

0.32% Water

Higher output with

Zeolite Membrane

Conventional

Polymer Membrane

Source: Economic comparison between azeotropic distillation and different hybrid systems combining distillation with pervaporation

for the dehydration of isopropanol, Elsevier, 2004

Opportunities for IT

Diffusion of computer programs for selection of Zeolitemembrane composition from databases

Opportunities for Pervaporation System

Suppliers

Huge market of the separation in the future

Huge business opportunity to introduce pervaporation to these plants

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

THANK YOU!

Appendix

Pervaporation

23

Advantages

• Low energy consumption.

• Low investment cost.

• Better selectivity without thermodynamic

limitations.

• Clean and close operation.

• No process wastes.

• Compact and scalable units.

Drawbacks

• Scarce membrane market.

• Lack of information.

• Low permeate flows.

• Better selectivity without thermodynamic

limitations.

• Limited applications:

• Organic substances dehydration.

• Recovery of volatile compounds at low

concentrations.

• Separation of azeotropic mixtures.

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

Summary (2)

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