Anode performance based on high temperature proton conducting - - PowerPoint PPT Presentation

Anode performance based on high temperature proton conducting electrolysers and a multitube module construction

• N. Bausá, M. Tarach and J.M. Serra

International discussion on hydrogen energy and applications November 2-4, 2016 Nantes (France)

Outline

2

 Introduction  Installation of the high pressure set-up  Compatibility and stability tests of the selected anode material

• Under 3 bars air + H2O (75% steam) at 700 °C for 72 h

 Symmetrical cells EIS:

• LSM/BCZY27 (50/50 and 60/40 vol.%)
• Study by changing pH2O, pO2 and pT
• Infiltrations (Pr-Ce, Pr, Ce, Zr)

 Multitube module design  Conclusions

3

Introduction

4

• The ELECTRA project:
• Scalable fabrication of tubular HTE cells with proton conducting

electrolytes for production of H2 from steam and renewable sources (solar, wind, geothermal, etc.)

Introduction

5

Introduction

• Utilise steam and heat procedures
• Produce wet H2
• Delamination of anode
• High operation temperatures ( >800 °C)
• Technology more investigated
• Utilise steam and heat procedures
• Produce dry H2 directly
• No anode delamination
• Low operation temperatures ( <700 °C)
• Technology less investigated
• Materials still in development

SOECs PCECs

2e- 2e- Hydrogen electrode Oxygen-ion conducting electrolyte Air electrode H2O+2e- H2+O2- O2-  O+2e- O+O O2 O2 H2 H2O

O2- O2- O2- O2- O2- O O O O O2- O2-

H H H H H H H H H H H H+ H+ H+ H+ H+ H+ H+ H+ H H H H H H H H

Hydrogen electrode Proton conducting electrolyte Air electrode 2H++2e- H2 H2O  2H+ + O2+2e- O2 2e- H2 2e-

O2-

H2O

H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H H

O O O O O2-

6

Installation of the high pressure set up

Installation of the high pressure set up

7

Reactor Steam Evaporator Saturator Manometers

Conditions:

• High pressure (20 bar)
• High temperature (500-800 °C)
• Utilises steam and different gases
• Pellets or tubes
• Dual atmosphere

BPR

8

Compatibility and stability tests

• f the selected anode material

Compatibility tests with BCZY27

9

LSM: La0.8Sr0.2MnO3 BCZY27: BaCe0.2Zr0.7Y0.1O3

Electrolyte material Possible Steam Electrode material Testing T, t (dry)

1100 °C/5 h

20 30 40 50 60 70 * BCZY27+LSM *

Stainless steal holder LSM BaZrO3 CeO2

I (a.u.) (log scale)

LSM BCZY27

2θ (º)

LSM: La0.8Sr0.2MnO3

CeO2 segregation also observed in BCZY27 after long times or higher sintering T

Stability tests under operating conditions

20 30 40 50 60 70 LSM as sintered LSM after 72h at 700؛C 2 bar (75% H2O)

2θ (؛) I (a.u.) (log scale)

LSM

LSM: La0.8Sr0.2MnO3

20 30 40 50 60 70 80 90 BCZY as sintered BCZY after 72h at 700ºC 2 bar (75% H2O)

2θ (º) I (a.u.) (log scale)

BaZrO3

BCZY: BaCe0.2Zr0.7Y0.1O3

3 bar air + H2O (75% steam) at 700 °C for 72 h

10

1µm LSM 1µm BCZY27

11

Symmetrical cells EIS

12

• LSM/BCZY27

 Infiltrations:

1. Pr – Ce (50 % vol.) [2M] 850 °C/2h 2. Pr [2M] 850 °C/2h 3. Ce[2M] 850 °C/2h 4. Zr [2M] 850 °C/2h

Symmetrical cells EIS

Øelectrolyte = 14 mm Øelectrode= 9 mm Thickness = 1.6 mm Electrolyte: BCZY27 Electrode: LSM/BCZY27 50 vol. % Current collector: Au

Symmetrical cells EIS

13

LSM/BCZY composite Conditions: Total P= 3 bar Steam 75% 3 days

0,9 1,0 1,1 1,2 1,3 1 10 100 1000

LSM/BCZY27 50 vol.% LSM/BCZY27 60/40 vol.%

Rp (Ω·cm

2)

1000/T (K

• 1)

800 750 700 650 600 550 500

T (ºC)

40 45 50

R at 700 ºC (Ω·cm

2)

Rp HF LF LF

% of BCZY in LSM

0,1 1 10 100

14

LSM/BCZY study by changing steam pressure, pO2 and pT

a) pH2O → pO2 ↗ pt ↗

0,0 0,3 0,6 0,9 0,01 R∝1/σ∝pO

• 0.25

2

700 ؛C

Rp HF (14-23 kHz) LF (0.9-1 Hz) LF (0.3-0.2 Hz)

Rp (Ω·cm

2)

pO2 (bar) pH2O=1.15 bar

0,01 0,1 1 5,5E-03 6E-03 6,5E-03 7E-03 7,5E-03 8E-03

700 ºC

BCZY27

σ

Electrolyte (S/cm)

pO2 (bar) pH2O=1.15 bar σ∝pO

0.019 2

b) pH2O ↗ pO2 → pt ↗

1 2 3 4 5 0,01 1 100

Rp HF (8-46 kHz) LF (0.9-2 Hz) LF (0.2-0.3 Hz)

R∝1/σ∝pH2O

0.046

700 ؛C Rp (Ω·cm

2)

pH2O (bar) pO2=0.1575 bar

1 10 4E-03 5E-03 6E-03 7E-03 8E-03

700 ºC

BCZY27

σ

Electrolyte (S/cm)

pH2O (bar) pO2=0.1575 bar σ∝pH2O

0.12

15

Infiltrations in LSM/BCZY

Symmetrical cells LSM/BCZY - Infiltrations

16

Conditions: Total P= 3 bar Steam 75% T = 700 °C

Infiltration Pr-Ce Rp = 0.64 Ω·cm2 at 700 °C Infiltration Zr Rp = 7.88 Ω·cm2 at 700 °C Infiltration Pr Rp = 0.33 Ω·cm2 at 700 °C

LSM/BCZY 50 vol. % LSM/BCZY 60/40 vol. %

Infiltration Pr Rp = 0.27 Ω·cm2 at 700 °C Infiltration Ce Rp = 1.04 Ω·cm2 at 700 °C

1,0 1,2 10

• 1

10 10

1

10

2

10

3

LSM/BCZY27 50 vol.% LSM/BCZY27 50 vol.% Infilt. Pr

Rp (Ω·cm

2)

1000/T (K

• 1)

750 700 650 600

T (ºC)

0,9 1 1,1 1,2 10

• 1

10 10

1

10

2

10

3

LSM/BCZY27 60/40 vol.% LSM/BCZY27 60/40 vol% Infilt. Pr-Ce LSM/BCZY27 60/40 vol% Infilt.Pr LSM/BCZY27 60/40 vol% Infilt. Zr LSM/BCZY27 60/40 vol% Infilt. Ce

Rp (Ω·cm

2)

1000/T (K

• 1)

800 750 700 650 600

T (ºC)

Bias – Infiltrations in LSM/BCZY 60/40 vol. %

17

Conditions: Total P= 3 bar Steam 75% T = 700 °C Infiltration Pr-Ce 850 °C in LSM/BCZY 60/40 vol. % Bias Infilt. Pr-Ce: i = 0.63 mA/cm2  Rp = 0.17 Ω·cm2 i = 5.7 mA/cm2  Rp = 0.087 Ω·cm2

1 2 3 4 5 6 0,1 1

LSM/BCZY 60/40 Infilt. Pr-Ce_3w_Current (3bar)

Rp (Ω·cm2) i (mA·cm

2)

0,0 0,5 1,0 1,5 2,0 0,0 0,5 1,0 1,5 2,0 LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Pr-Ce LSM/BCZY 60/40 vol.% Infilt. Pr-Ce_bias_1mA

• Z'' (Ω·cm2)

Z' (Ω·cm

2)

0,0 0,1 0,2 0,00 0,02 0,04 0,06 0,08

10

• 3

10

• 2

10

• 1

10 10

10

10

10

10

0,00 0,02 0,04 0,06 0,08

• Z'' (Ω·cm

2)

Z' (Ω·cm

2)

1mA 3mA 5mA 7mA 9mA

• Z'' (Ω·cm

2)

Frequency (Hz)

MF HF

18

Conditions: Total P= 3 bar Steam 75% T = 700 °C Infiltration Pr 850 °C in LSM/BCZY

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

LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Pr LSM/BCZY 60/40 vol.% Infilt. Pr_bias_1mA

• Z'' (Ω·cm

2)

Z' (Ω·cm

2)

Bias Infilt. Pr: i = 0.63 mA/cm2  Rp = 0.27 Ω·cm2 i = 3.2 mA/cm2  Rp = 0.18 Ω·cm2 Infiltration Zr 850 °C in LSM/BCZY Bias Infilt. Zr: i = 0.63 mA/cm2  Rp = 2.53 Ω·cm2 i = 6.99 mA/cm2  Rp = 1.01 Ω·cm2

2 4 6 2 4 6

LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Zr 850 ºC LSM/BCZY 60/40 vol.% Infilt. Zr 850C_bias_1mA

• Z'' (Ω·cm

2)

Z' (Ω·cm

2)

Bias – Infiltrations in LSM/BCZY 60/40 vol. %

19

Conditions: Total P= 3 bar Steam 75% T = 700 °C Infiltration Ce 850 °C in LSM/BCZY Bias Infilt. Ce: i = 0.63 mA/cm2  Rp = 0.54 Ω·cm2 i = 5.72 mA/cm2  Rp = 0.05 Ω·cm2

Bias – Infiltrations in LSM/BCZY 60/40 vol. %

1 2 3 1 2 3

LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Ce 850 ºC LSM/BCZY 60/40 vol.% Infilt. Ce 850C_bias_1mA

• Z'' (Ω·cm

2)

Z' (Ω·cm

2)

5 10 15 20 25 2 4 6 8 10

Rp (Ω·cm

2)

t (h) LSM/BCZY 60/40 vol.% Infilt. Pr-Ce 50% LSM/BCZY 60/40 vol.% Infilt. Pr LSM/BCZY 60/40 vol.% Infilt. Zr LSM/BCZY 60/40 vol.% Infilt. Ce

Good stability!

Comparative infiltrations

20

Conditions: Total P= 3 bar Steam 75% T = 700 °C Infiltrations in LSM/BCZY 60/40 vol. %

1 2 3 4 5 6 0,01 0,1 1 10

LSM/BCZY 60/40 Infilt. Pr-Ce LSM/BCZY 60/40 Infilt. Pr LSM/BCZY 60/40 Infilt. Zr LSM/BCZY 60/40 Infilt. Ce

Rp (Ω·cm

2)

i (mA·cm

2)

SEM micrographs of LSM/BCZY 60/40 % vol. infiltrated with Pr-Ce 50% (850 °C)

21

Powder 850 °C

Fresh sample as a layer

Electrode after operating conditions 200 nm 200 nm 200 nm

• Ce
• Pr

Electrode Electrolyte 40 µm

Good infiltration

10 µm

Electrode

22

Multitube module

Multitube module

23

Working conditions:

• Temperature: 700 °C
• Pressure:

 Total: 50 bar  Steam: 10 bar

• Steam temperature: 250-300°C

Temperature management system:

• Cooling system allows applying low temperature gaskets
• Heat recovery from cooling system
• External heating system for startup

Multitube module achieves stable operation for H2O electrolysis with H2 production of 250 Ln/h using 1kW of power

Cooling system Evaporator Controller Pump Water Container Power source Gas analyser

H2 Electrolysis Co-electrolysis

24 24

Electrical energy management system:

• Positive (+) current contact shared by all tubes
• Negative (-) current contacts independent for each tube
• One tube consists of 5 segments connected in series

Tube materials

• Anode: LSM/BCZY or BGLC/BCZY (UiO)
• Cathode: Ni-BCZY cermet
• Electrolyte: BCZY

Multitube module

25

Geometry optimisation:

• Mechanical analysis (strength, thermal resistance)
• Fluid dynamics simulation (temperature profile and speed flow)

Speed profile

Multitube module

26

Geometry optimisation:

• Mechanical analysis (strength, thermal resistance)
• Fluid dynamics simulation (temperature profile and speed flow)

Temperature Profile

Multitube module

27

Stress Displacement Geometry optimisation:

• Mechanical analysis (strength, thermal resistance)
• Fluid dynamics simulation (temperature profile and speed flow)

Multitube module

28

Conclusions

• A thorough study by changing the measurement conditions (steam, pO2 and total

pressures)

• LSM/BCZY27 50/50 vol. % infiltrated with Pr shows the lower electrode Rp (700 °C)
• LSM/BCZY27 60/40 vol. % infiltrated with Pr-Ce and Ce show the lower electrode

Rp when a current is applied (700 °C)

• Construction of a multitube module which allows efficient electrolysis of water

and co-electrolysis of steam and CO2 mixtures to obtain hydrocarbons

Financial support by the Spanish Government (Grants SEV-2012-0267 and MAT2011-29020-C02-01) and by the EU through FP7 Electra Project (Grant Agreement 621244)

Acknowledgements My colleagues at ITQ/ELECTRA:

Thank you for your attention