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  Introduction  Installation of the high pressure set-up  Compatibility and stability tests of the selected anode material • Under 3 bars air + H 2 O (75% steam) at 700 °C for 72 h  Symmetrical cells EIS: • LSM/BCZY27 (50/50 and 60/40 vol.%)  Study by changing pH 2 O, p O 2 and p T  Infiltrations (Pr-Ce, Pr, Ce, Zr)  Multitube module design  Conclusions 2

Introduction 3

Introduction  The ELECTRA project: • Scalable fabrication of tubular HTE cells with proton conducting electrolytes for production of H 2 from steam and renewable sources (solar, wind, geothermal, etc.) 4

Introduction SOECs H H 2 H 2 O H O 2- H H O 2- H H 2e - H H H  Utilise steam and heat procedures H 2 O+2e -  H 2 +O 2- Hydrogen electrode  Produce wet H 2 O 2- Oxygen-ion conducting O 2- O 2-  Delamination of anode electrolyte O 2- O 2-  High operation temperatures ( >800 ° C) O 2-  O+2e - Air electrode  Technology more investigated O+O  O 2 O O 2e - O O H O 2 H H H 2 H H H H H 2e - H H PCECs H 2H + +2e -  H 2 Hydrogen electrode  Utilise steam and heat procedures H + H +  Produce dry H 2 directly H + H + H + Proton conducting H + H + electrolyte H + H +  No anode delamination H + H + H + H + H + H + H + H + H + H +  Low operation temperatures ( <700 ° C) Air electrode H2O  2H + + O 2 +2e -  Technology less investigated O H 2e - H 2 O H O 2- O  Materials still in development H O 2- H O O 2 H O 5

Installation of the high pressure set up 6

Installation of the high pressure set up Steam Evaporator Conditions: - High pressure (20 bar) - High temperature (500-800 °C) BPR - Utilises steam and different gases - Pellets or tubes - Dual atmosphere Manometers Reactor Saturator 7

Compatibility and stability tests of the selected anode material 8

Compatibility tests with BCZY27 Possible Steam Electrode material Electrolyte material Testing T, t (dry) BCZY27: BaCe 0.2 Zr 0.7 Y 0.1 O 3 1100 °C/5 h LSM: La 0.8 Sr 0.2 MnO 3 LSM: La 0.8 Sr 0.2 MnO 3 BaZrO 3 CeO 2 Stainless steal holder BCZY27+LSM * LSM I (a.u.) (log scale) * CeO 2 segregation also observed in BCZY27 after long times or higher sintering T LSM BCZY27 20 30 40 50 60 70 2 θ (º) 9

Stability tests under operating conditions BCZY: BaCe 0.2 Zr 0.7 Y 0.1 O 3 BCZY after 72h at 700ºC 2 bar (75% H 2 O) I (a.u.) (log scale) BCZY27 BCZY as sintered BaZrO 3 1µm 20 30 40 50 60 70 80 90 2 θ (º) LSM: La 0.8 Sr 0.2 MnO 3 LSM LSM after 72h at 700؛C 2 bar (75% H 2 O) I (a.u.) (log scale) LSM as sintered LSM 1µm 20 30 40 50 60 70 2 θ (؛) 3 bar air + H 2 O (75% steam) at 700 °C for 72 h 10

Symmetrical cells EIS 11

Symmetrical cells EIS Electrolyte: BCZY27  LSM/BCZY27 Electrode : LSM/BCZY27 50 vol. % Current collector : Au  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 Ø electrolyte = 14 mm Ø electrode = 9 mm Thickness = 1.6 mm 12

Symmetrical cells EIS LSM/BCZY composite T (ºC) 800 750 700 650 600 550 500 100 LSM/BCZY27 50 vol.% 1000 LSM/BCZY27 60/40 vol.% 2 ) 10 R at 700 ºC ( Ω ·cm 2 ) 100 R p ( Ω ·cm 1 10 R p HF LF LF 0,1 1 40 45 50 0,9 1,0 1,1 1,2 1,3 % of BCZY in LSM -1 ) 1000/T (K Conditions: Total P= 3 bar Steam 75% 3 days 13

LSM/BCZY study by changing steam pressure, p O 2 and p T 8E-03 pH 2 O → a) pH 2 O=1.15 bar pH 2 O=1.15 bar R ∝1/σ∝ pO -0.25 7,5E-03 pO 2 ↗ 2 Electrolyte (S/cm) p t ↗ 7E-03 σ∝ pO 2 ) 0.019 R p ( Ω ·cm 2 6,5E-03 σ R p 6E-03 HF (14-23 kHz) LF (0.9-1 Hz) 700 ؛C LF (0.3-0.2 Hz) 700 ºC BCZY27 0,01 5,5E-03 0,0 0,3 0,6 0,9 0,01 0,1 1 pO2 (bar) b) pH 2 O ↗ pO2 (bar) 8E-03 100 pO 2 → pO 2 =0.1575 bar pO 2 =0.1575 bar R ∝ 1/ σ∝ pH 2 O 0.046 7E-03 p t ↗ Electrolyte (S/cm) 6E-03 2 ) R p ( Ω ·cm 1 σ∝ pH 2 O 0.12 σ 5E-03 R p HF (8-46 kHz) LF (0.9-2 Hz) 700 ؛C 700 ºC LF (0.2-0.3 Hz) BCZY27 0,01 4E-03 0 1 2 3 4 5 1 10 pH 2 O (bar) pH 2 O (bar) 14

Infiltrations in LSM/BCZY 15

Symmetrical cells LSM/BCZY - Infiltrations LSM/BCZY 60/40 vol. % LSM/BCZY 50 vol. % T (ºC) T (ºC) 800 750 700 650 600 750 700 650 600 3 10 3 10 LSM/BCZY27 60/40 vol.% LSM/BCZY27 50 vol.% LSM/BCZY27 60/40 vol% Infilt. Pr-Ce LSM/BCZY27 60/40 vol% Infilt.Pr LSM/BCZY27 50 vol.% Infilt. Pr LSM/BCZY27 60/40 vol% Infilt. Zr 2 10 2 10 LSM/BCZY27 60/40 vol% Infilt. Ce 2 ) 2 ) R p ( Ω ·cm R p ( Ω ·cm 1 10 1 10 0 10 0 10 -1 10 -1 10 0,9 1 1,1 1,2 1,0 1,2 -1 ) 1000/T (K -1 ) 1000/T (K Infiltration Pr Infiltration Pr-Ce Infiltration Pr Rp = 0.33 Ω ·cm 2 at 700 °C Rp = 0.64 Ω ·cm 2 at 700 °C Rp = 0.27 Ω ·cm 2 at 700 °C Infiltration Zr Infiltration Ce Rp = 7.88 Ω ·cm 2 at 700 °C Rp = 1.04 Ω ·cm 2 at 700 °C Conditions: Total P= 3 bar Steam 75% T = 700 °C 16

Bias – Infiltrations in LSM/BCZY 60/40 vol. % Infiltration Pr-Ce 850 °C in LSM/BCZY 60/40 vol. % 0,08 0,08 1mA Conditions: 0,06 0,06 MF 3mA 2 ) Total P= 3 bar 5mA 2 ) -Z'' ( Ω ·cm -Z'' ( Ω ·cm 0,04 0,04 7mA Steam 75% 9mA 0,02 0,02 HF T = 700 °C 0,00 0,00 0,0 0,1 0,2 -3 -2 -1 0 1 2 3 4 5 10 10 10 10 10 10 10 10 10 Z' ( Ω ·cm 2 ) Frequency (Hz) 1 2,0 LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 Infilt. Pr-Ce_3w_Current (3bar) LSM/BCZY 60/40 vol.% Infilt. Pr-Ce LSM/BCZY 60/40 vol.% Infilt. Pr-Ce_bias_1mA 1,5 R p ( Ω ·cm 2 ) -Z'' ( Ω ·cm 2 ) 1,0 0,5 0,1 0,0 0 1 2 3 4 5 6 0,0 0,5 1,0 1,5 2,0 2 ) Z' ( Ω ·cm 2 ) i (mA·cm Bias Infilt. Pr-Ce: i = 0.63 mA/cm 2  Rp = 0.17 Ω ·cm 2 i = 5.7 mA/cm 2  Rp = 0.087 Ω ·cm 2 17

Bias – Infiltrations in LSM/BCZY 60/40 vol. % Infiltration Pr 850 °C in LSM/BCZY Infiltration Zr 850 °C in LSM/BCZY 0,8 LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Pr LSM/BCZY 60/40 vol.% Infilt. Zr 850 ºC 6 LSM/BCZY 60/40 vol.% Infilt. Pr_bias_1mA LSM/BCZY 60/40 vol.% Infilt. Zr 850C_bias_1mA 0,6 2 ) -Z'' ( Ω ·cm 4 2 ) -Z'' ( Ω ·cm 0,4 2 0,2 0,0 0 0,0 0,2 0,4 0,6 0,8 0 2 4 6 Z' ( Ω ·cm 2 ) Z' ( Ω ·cm 2 ) Bias Infilt. Pr: Bias Infilt. Zr: i = 0.63 mA/cm 2  Rp = 0.27 Ω ·cm 2 i = 0.63 mA/cm 2  Rp = 2.53 Ω ·cm 2 i = 3.2 mA/cm 2  Rp = 0.18 Ω ·cm 2 i = 6.99 mA/cm 2  Rp = 1.01 Ω ·cm 2 Conditions: Total P= 3 bar Steam 75% T = 700 °C 18

Bias – Infiltrations in LSM/BCZY 60/40 vol. % Infiltration Ce 850 °C in LSM/BCZY 3 10 LSM/BCZY 60/40 vol.% LSM/BCZY 60/40 vol.% Infilt. Ce 850 ºC LSM/BCZY 60/40 vol.% Infilt. Ce 850C_bias_1mA 8 2 LSM/BCZY 60/40 vol.% Infilt. Pr-Ce 50% 2 ) 2 ) 6 -Z'' ( Ω ·cm Rp ( Ω ·cm LSM/BCZY 60/40 vol.% Infilt. Pr LSM/BCZY 60/40 vol.% Infilt. Zr LSM/BCZY 60/40 vol.% Infilt. Ce 4 1 2 0 0 0 5 10 15 20 25 0 1 2 3 t (h) Z' ( Ω ·cm 2 ) Bias Infilt. Ce: Good stability! i = 0.63 mA/cm 2  Rp = 0.54 Ω ·cm 2 Conditions: i = 5.72 mA/cm 2  Rp = 0.05 Ω ·cm 2 Total P= 3 bar Steam 75% T = 700 °C 19

Comparative infiltrations Infiltrations in LSM/BCZY 60/40 vol. % Conditions: 10 LSM/BCZY 60/40 Infilt. Pr-Ce Total P= 3 bar LSM/BCZY 60/40 Infilt. Pr Steam 75% LSM/BCZY 60/40 Infilt. Zr T = 700 °C LSM/BCZY 60/40 Infilt. Ce 1 2 ) R p ( Ω ·cm 0,1 0,01 0 1 2 3 4 5 6 2 ) i (mA·cm 20

SEM micrographs of LSM/BCZY 60/40 % vol. infiltrated with Pr-Ce 50% (850 °C) Powder 850 °C Fresh sample as a layer Electrode 200 nm 10 µm 200 nm Electrode after operating conditions Electrode • Ce • Pr Electrolyte 200 nm 40 µm Good infiltration 21

Multitube module 22

Multitube module Multitube module achieves stable operation for H 2 O electrolysis with H 2 production of 250 L n /h using 1kW of power 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 Power source Electrolysis Controller Co-electrolysis H 2 Pump Evaporator Gas analyser Water Container Cooling system 23

Multitube module Tube materials  Anode: LSM/BCZY or BGLC/BCZY (UiO)  Cathode: Ni-BCZY cermet  Electrolyte: BCZY 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 24 24

Multitube module Geometry optimisation:  Mechanical analysis (strength, thermal resistance)  Fluid dynamics simulation (temperature profile and speed flow) Speed profile 25

Multitube module Geometry optimisation:  Mechanical analysis (strength, thermal resistance)  Fluid dynamics simulation (temperature profile and speed flow) Temperature Profile 26

Multitube module Geometry optimisation:  Mechanical analysis (strength, thermal resistance)  Fluid dynamics simulation (temperature profile and speed flow) Displacement Stress 27