Técnicas de Procesamiento, Análisis de Datos y Presentación de

Current collectors for both fuel electrode and air electrode were applied before electrochemical measurements. The selections for current collector for different electrode materials will be discussed in following chapters (chapter 4-5).

Chapter

Fig. 2.6

Fig. 2.6 is the schematic picture of the home to-test single cell was amounted

tube on the cathode side us was placed into a temperature

cathode part at bottom. Pt probes were used to connect the cell to electrochemical instruments. An R-type thermocouple was placed close to

monitor the sample temperature operating temperature, the test ch

(0.5oC/min), to properly cure the ceramic cement. Subsequently, the test chamber was heated directly to the operating temperature

Chapter 2: Methods and techniques

Schematic graph of sing cell testing set-up

Fig. 2.6 is the schematic picture of the home-built single cell testing set

amounted to an alumina tube, and it was sealed to the alumina tube on the cathode side using ceramic cement (Aremco 552). Then the whole assembly

temperature-controlled furnace, with the anode part sitting on top Pt probes were used to connect the cell to electrochemical type thermocouple was placed close to the sample, in order to monitor the sample temperature during operation. Before heating the furnace up to operating temperature, the test chamber was heated to 300oC at a very low ramp rate , to properly cure the ceramic cement. Subsequently, the test chamber was heated directly to the operating temperature at a ramp rate of 3oC/min.

built single cell testing set-up. The ready- was sealed to the alumina hen the whole assembly controlled furnace, with the anode part sitting on top and Pt probes were used to connect the cell to electrochemical sample, in order to . Before heating the furnace up to at a very low ramp rate , to properly cure the ceramic cement. Subsequently, the test chamber was

Chapter

2.3.2 Gas supply

During electrochemical measurement, different fuel gas was fed into cathode chamber at a certain flow rate controlled by mass flow controllers (MFC

AALBORG and CO2 MFC from

the downstream of the cathode to check se

respect to the anode side, air was flushed through at a constant flow rate, during the whole test.

Fig. 2.7Gas lines for fuel gas supply with the incorporation of for steam electrolysis/steam

wrapped with heating tapes when steam generator was on)

Fig. 2.7 exhibits the cathode gas lines for fuel gas

fuel and air electrode were exposed to ambient air except the Ni/YSZ cathode SOEC for which N2 rather air was flowed through fuel electrode.

humidified 5% H2/Argon was circuit voltage (OCV) to ch fuel gas. Humidified 5% H

cermet cathode SOEC. Reduction was performed in the experimental setup in s OCV value of the cell stayed constant.

5%H2/Ar was run for a certain time to get a steady state before providing fuel gas. Chapter 2: Methods and techniques

a

measurement, different fuel gas was fed into cathode chamber at a certain flow rate controlled by mass flow controllers (MFC,

MFC from Cole-Parmer), and bubble leak test was conducted on the downstream of the cathode to check seals and leakage across electrolyte. respect to the anode side, air was flushed through at a constant flow rate,

Gas lines for fuel gas supply with the incorporation of steam generation system for steam electrolysis/steam-carbon dioxide co-electrolysis (the highlighted gas line was

wrapped with heating tapes when steam generator was on)

Fig. 2.7 exhibits the cathode gas lines for fuel gases supply. During heating up, bot de were exposed to ambient air except the Ni/YSZ cathode SOEC for rather air was flowed through fuel electrode. At the operation temperature,

was firstly fed into the cathode chamber to evaluate

o check if the cell was well sealed, before the introduction of H2/Ar was also used for NiO reduction in the case of Ni/YSZ Reduction was performed in the experimental setup in s

OCV value of the cell stayed constant. Regarding the LSCM based cathode SOEC, was run for a certain time to get a steady state before providing fuel gas.

b

measurement, different fuel gas was fed into cathode chamber , CO MFC from bubble leak test was conducted on als and leakage across electrolyte. With respect to the anode side, air was flushed through at a constant flow rate, 100ml/min

steam generation system (the highlighted gas line was wrapped with heating tapes when steam generator was on)

During heating up, both the de were exposed to ambient air except the Ni/YSZ cathode SOEC for At the operation temperature, into the cathode chamber to evaluate cell open eck if the cell was well sealed, before the introduction of was also used for NiO reduction in the case of Ni/YSZ Reduction was performed in the experimental setup in situ until the LSCM based cathode SOEC, was run for a certain time to get a steady state before providing fuel gas.

Chapter 2: Methods and techniques

Concerning CO2 electrolysis, CO2/CO gas mixture with various CO2/CO ratios, at a

total flow rate of 30 ml/min was introduced into the fuel side, i.e. cathode side in SOEC. Prior to entry cathode chamber, CO2and CO gas were connected to a gas mixer to get a uniform mixture gas. The initial performance for the cells with different cathode material was characterized in atmospheres with different CO2/CO ratios ranging from

90/10 to 30/70 controlled by MFCs. CO2 electrolysis was also conducted on the GDC

impregnated LSCM cathode SOEC in fuels without protective CO gas, at this

circumstance, N2 was used as saturate gas for CO2, and cell performance was

characterized in different CO2/N2 ratio gas mixtures (see section 6.3). In some cases, 5%H2/Ar, at a flow rate of 10ml/min controlled by a separate MFC (from Brooks), was introduced into fuel electrode, along with CO2/CO or CO2/N2mixture, in order to study the effect of presence of H2on CO2reduction reaction kinetics.

Regarding steam electrolysis and/or steam-carbon dioxide co-electrolysis, a steam generation system was incorporated for fuel gas supply. Steam was generated by heating a saturator (BekkTech BT-512 system) at a certain temperature to obtain the required steam concentration. The generated steam was carried to the fuel compartment by 5%H2/Ar or pure H2gas in steam electrolysis study, and all the gas line from the exit of saturator to furnace was wrapped with insulated heating tapes (from Omega Engineering), as shown in Fig. 2.7 in yellow colour, which were heated at around 100oC to prevent steam from condensation. The flow rate for steam-containing fuel ranged from 10 to 30 ml/min. In co-electrolysis studies, steam carried by 5% H2/Ar or H2and CO2-CO mixture were joined at some point of gas line (route a in Fig. 2.7) before being co-fed to fuel compartment. Alternatively, steam was carried by CO2-CO mixture (route b in Fig. 2.7) as feed gas for co-electrolysis measurement. The total feed flow rate was 30 min/min for co-electrolysis studies. More detailed information will be found in chapter 7 for fuel gas compositions for steam electrolysis/co-electrolysis studies.