16/09/2014

Salinity Gradient Energy by Reversed Electrodialysis - REAPower

International Symposium Innovative Desalination Technologies, Seoul

INES session, 03 September 2014

Inge Genné, Joost Helsen, VITO, Belgium

Andrea Cippolina, Univ. of Palermo, Italy

16/09/2014 2 © 2014, VITO NV

VITO, VISION ON TECHNOLOGY

WHO IS VITO ?

» A LEADING EUROPEAN INDEPENDENT RESEARCH CENTRE, LOCATED IN FLANDERS/BELGIUM;

» 750 PEOPLE, ACTIVE IN THE AREAS OF CLEANTECH AND SUSTAINABLE DEVELOPMENT;

» ELABORATING SOLUTIONS FOR THE LARGE SOCIETAL CHALLENGES OF TODAY.

More sustainable industry Reorganisation of the environment

Reduce dependence on

fossil fuels

16/09/2014 3 © 2014, VITO NV

New value chains • Algae to products

• Bio-aromatics

• CO2 to chemicals

Separation and Conversion technologies (~100 people)

SEPARATION TECHNOLOGY

CONVERSION TECHNOLOGY

Our Technologies/ Expertise

Enabling competences

Markets

MEMBRANES

ELECTRODES

Society

Industry

Spin-offs

Open innovation

Contract research

Our Stakeholders

Chemical processing / PI

Biobased economy

Resource recovery

16/09/2014 4 © 2014, VITO NV

VITO as Product developer…

» Membrane development (20 patents)

Reinforced polymeric membranes (flat sheet-IPC, tubular, capillary)

Membrane contactors

Functionalised ceramic membranes

» Electrodes and stacks (carbon based)

16/09/2014 5 © 2014, VITO NV

VITO as Technology integrator…

» Membrane technology for water processing and resource recovery

» Equipment: MF/UF, NF, RO, MBR, ED, RED, MD, CDI

» Integrating separation processes with conversion processes

» Setting-up demonstrators from lab to pilot scale

» Integrated approach: engineering, analysis, TEA…

16/09/2014 6 © 2014, VITO NV

The REAPower Project

» Project title: Reverse Electrodialysis Alternative Power Production

» Call identifier: FP7-ENERGY-2010-FET (Future Emerging Technologies for Energy Applications)

» Starting date: 1 October 2010

» Closing date: 30 September 2014

Main facts:

The objective of REAPower is to prove the concept of electricity production

through SGP-RE using brine and sea (/brackish) water and to develop the

necessary materials, components and processes.

16/09/2014 7 © 2014, VITO NV

CATHODE

ANODE

e-

e-

ELECTRODE RINSE

C D C

+ + - -

I, J+

The Reverse Electrodialysis technology

16/09/2014 8 © 2014, VITO NV

SGP-RE applications

Concentrate

=

Brine

Diluate

=

Brackish or

sea water

Blue Energy

Concentrate

=

Sea water

Diluate

=

river water

16/09/2014 9 © 2014, VITO NV

16/09/2014 10 © 2014, VITO NV

The REAPower Project

R&D strategy

Development of new Ion Exchange Membranes for highly

concentrated solutions

Selection of best conditions for redox couple/spacers/stack design

Wide experimental investigation on lab-scale stack

Development/validation of a predictive modelling tool

Economic analysis and process sustainability on large scale (ongoing)

The idea

to produce energy from salinity gradients generated by

sea/brackish water and ultra-concentrated brines

16/09/2014 11 © 2014, VITO NV

Increased permselectivity

Reduced membrane resistance

Permselectivity has achieved

values of 65% for AEM and up to

90% for CEM when in contact

with almost saturated brine

Membrane specific resistance

reduced to 1.5-2.5 Ω∙cm2 (possibly

lower in the near future – thinner

membranes)

Improvements in membranes development

16/09/2014 12 © 2014, VITO NV

Redox couples selection

New stack design Two optimized stack geometries

designed, constructed and tested

Currently available for pilot testing

Investigated redox couples under

different conditions:

FeCl3/FeCl2

K3Fe(CN)6/K4Fe(CN)6

Fe(III)-EDTA/Fe(II)-EDTA

Electrochemical aspects and stack design

16/09/2014 13 © 2014, VITO NV

Experimental conditions investigated:

fluid velocity (0.1 – 4 cm/s) feed temperature (20 – 40 °C) number of cell pairs (5 – 50) concentration of redox couple (0.1 – 0.3 M of K3Fe(CN)6/K4Fe(CN)6) salt concentration of both solutions. Membrane thickness

Experimental investigation at lab-scale

Brine IN

CELLS

STACK

Potentiostat/

Galvanostat

Brine IN

tank

Seawater IN

tank

Seawater OUT

tank

Brine OUT

tank

Electrode Rinse

Solution

tank

Seawater IN

ERS IN ERS OUT

Seawater OUT

Brine OUT

16/09/2014 14 © 2014, VITO NV

Showing that the SGP-RE installation works…

16/09/2014 15 © 2014, VITO NV

Max power density (net): Power density – Hydraulic losses

-5,0

-4,0

-3,0

-2,0

-1,0

0,0

1,0

2,0

3,0

0 1 2 3 4 5

Max

Pd [

W/m

2 c

ell

pai

r]

fluid velocity [cm/s]

Experimental investigation on a lab-scale unit

e.g. Effect of fluid velocity on power output

Stack equipped with 50 cell pairs, Fujifilm membranes, Deukum 270 µm spacers .Brine solution: 5 M NaCl, seawater: 0.5 M NaCl. T=20°C. Electrode rinse solution: 0.1 M K3Fe(CN)6 / K4Fe(CN)6 ·3H2O + 2.5 M NaCl.

Max power density (gross)

16/09/2014 16 © 2014, VITO NV

Experimental investigation on a lab-scale unit e.g. Effect of the conc. of the concentrated solution (1 - 5 M)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 40 80 120

Po

we

r d

en

sity

[W

/m2

cell

pai

r]

current density [A/m2]

5 M

4 M

2,86 M

1,96 M

1 Mincreasing

Cconcentrate

Cdil=0.55 M

Power density vs. current density

-1,0

0,0

1,0

2,0

3,0

4,0

5,0

0 1 2 3 4 5

Max

Pd

[W

/m2 c

ell

pai

r]

Concentration of the conc. solution [M]

Maximum power density vs. Cconc

increasing

Cconcentrate Gross Pd

Stack equipped with 50 cell pairs, Fujifilm membranes, Deukum 270 µm spacers . Seawater: 0.55 M NaCl. T=20°C. Fluid velocity: 1 cm/s. Electrode rinse solution: 0.1 M K3Fe(CN)6 / K4Fe(CN)6 ·3H2O + 2.5 M NaCl.

16/09/2014 17 © 2014, VITO NV

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

0 0,2 0,4 0,6 0,8 1

Max

Pd

[W

/m2 c

ell

pai

r]

Concentration of the diluted solution [M]

Experimental investigation on a lab-scale unit e.g. Effect of the concentration of the diluted solution (0.1 - 1 M)

Cconc=5 M decreasing

Cdilute

Power density vs. current density

Max Pd= 4.5 W/m2

decreasing

Cdilute

Maximum power density vs. Cdilute

Gross Pd

Stack equipped with 50 cell pairs, Fujifilm membranes, Deukum 270 µm spacers . Brine: 5 M NaCl. T=20°C. Fluid velocity: 1 cm/s. Electrode rinse solution: 0.1 M K3Fe(CN)6 / K4Fe(CN)6 ·3H2O + 2.5 M NaCl.

16/09/2014 18 © 2014, VITO NV

50 cell pairs; Deukum spacers [thickness 270 µm] - Brine 5 M; Electrode rinse solution [( K3Fe(CN)6 0,1 M, K4Fe(CN)6 ·3H2O 0,3M; NaCl 2,5M), flow rate 30l/h].

Experimental investigation on a lab-scale unit

MAX power output conditions: T = 40°C & 0.1M (d) and 5M (c) Membrane thickness

0

2

4

6

8

10

12

0 50 100 150

Pd

en

sity

[W

/m2]

i [A/m2]

0

2

4

6

8

10

12

0 50 100 150P

den

sity

[W

/m2]

i [A/m2]

Thick membranes (provided by Fujifilm)

Power density between 15 and 20 W/m2 can be expected with larger number of cell pairs, i.e. reducing the effect of blank resistance (with model solutes!)

Thin membranes (provided by Fumatech)

16/09/2014 19 © 2014, VITO NV

Computational Fluid Dynamics of SGP-RE stack

Lower scale info

Process model implementation

Multi scale model implementation

Experimental tests on SGP-RE stacks

validation Multi scale model validation

Model predictions on process performances & optimisation

CFD modelling and process simulation

Multi-Scale Modelling approach:

16/09/2014 20 © 2014, VITO NV

Model used to predict parameter dependences

e.g. Influence of inlet concentrations 0.5

0.5

1

1

1

1.5

1.5

1.5

2

2

2

2

2

2.52.5

2.5

2.5

2.5

2.5

33

3

3

3

3.53.5

3.5

3.5

4

44.03

Max Power density (W/m2 cell pair)

HIGH concentration (mol/l)

LO

W c

oncentr

ation (

mol/l)

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

50 cell pairs

v = 1 cm/s

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0.0 0.1 0.2 0.3 0.4 0.5

Max

Po

wer

den

sity

, Pd

,max

(W/m

2ce

ll p

air)

diluate concentration, CLOW (mol/l)

T=20°CT=30°CT=40°C

N = 50 cellsCHIGH = 4.8 Mv = 1 cm/s

T

BEST conditions: brackish water (0.05 – 0.1 M) + brine (4.5 – 5 M)

Simulations of a 50-cells stack equipped with Fujifilm membranes, Deukum spacers; fluid velocity inside channels: 1 cm/s; T=20°C. Blank resistance: 0.4 Ω.

seawater brine

rive

r w

ater

se

awat

er

Max Pd= 5.3 W/m2 (+31%)

Influence of T

16/09/2014 21 © 2014, VITO NV

The REAPower prototype installation site

The singular framework of Trapani saltworks

Prototype installation site

16/09/2014 22 © 2014, VITO NV

Direct access to both saturated brine and seawater from open channels

Installation place within an old, restructured WINDMILL

The REAPower prototype installation site

The “Ettore-Infersa” saltworks

16/09/2014 23 © 2014, VITO NV

Site features

• Seawater availability: unlimited;

• Brine availability: 10-15 m3/h (much larger with feed-recycle);

• Brine concentration: variable between 250 and 320 gr/lt.

Prototype features

• RED stack dimensions: 44x44 cm

• 500 cell pairs;

Expected power density: > 5 W/m2

Prototype installation: plant specifications

16/09/2014 24 © 2014, VITO NV

Instruments Tanks

T-1

Open sea/channel SEAWATER

Discharge channel

BRINEbasins

wellBRACKISH WATER

SGP-REUNIT

P-2

T-3

T-2

Self-cleaningfilter - 1

V-48

V-2

17

P-1

Self-cleaningfilter - 2

V-3

brine

V-1

16

18

V-5

Brackish water

11

12

P-5

13

14

3

V-11

4

V-12

To channel

brine

seawater

2

7

Backwashing water

FI-4

FI-10

HCl

P-6

15

FI-13

To channel

REMARKS:

· Two feed tanks

· Electrode solution: FeCl2/FeCl3

· Recycle of both solutions

P-3

P-4

V-8PR-1

9

V-10

V-9

To channel

To channel

Diluted recycle

V-6

V-14

V-136

V-7

10

V-15 V-16

waste

P T C

C T

P

pH

P

T

C

T

C

P

T

C

Layout 4

Brine recycle

Centrifugal pump

Rotary pump

Proportioning pump

Check valve

Membrane valve

Ball valve

Float valve

Flowmeter

PH

P

C

T

Conductivity indicator

pH indicator

Temperature indicator

Pressure indicator

Pressure reducer

T-1 for brackishwater/seawater

T-2 for brine

T-3 for electrode solution

Backwashing water

Process Flow Diagram & recycle option

16/09/2014 25 © 2014, VITO NV

Status: - Optimisation of pilot on-going - Technico-economical evaluation for different applications on-going

More information: www.reapower.eu (Movie shortly available)