scholarly journals Improving the Efficiency of High-Temperature Electrolysis of Carbon Dioxide in a Solid Oxide Cell

2019 ◽  
Vol 91 (1) ◽  
pp. 2623-2630
Author(s):  
Ann V Call ◽  
Thomas D Holmes ◽  
Khelifa Yanallah ◽  
Pratik D Desai ◽  
William B Zimmerman ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Solid Oxide ◽  
Solid Oxide Cell ◽  
High Temperature Electrolysis

Polarization mechanism of high temperature electrolysis in a Ni–YSZ/YSZ/LSM solid oxide cell by parametric impedance analysis

2013 ◽  
Vol 232 ◽  
pp. 80-96 ◽  
Author(s):  
Eui-Chol Shin ◽  
Pyung-An Ahn ◽  
Hyun-Ho Seo ◽  
Jung-Mo Jo ◽  
Sun-Dong Kim ◽  
...  
Keyword(s):  
High Temperature ◽  
Impedance Analysis ◽  
Solid Oxide ◽  
Polarization Mechanism ◽  
Solid Oxide Cell ◽  
High Temperature Electrolysis

Hydrogen Production through High-temperature Electrolysis in a Solid Oxide Cell

2004 ◽  
pp. 183-200
Author(s):  
S. Elangovan ◽  
Joseph Hartvigsen ◽  
J. Stephen Herring ◽  
Paul Lessing ◽  
James E. O'Brien ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Solid Oxide ◽  
Solid Oxide Cell ◽  
High Temperature Electrolysis

scholarly journals Degradation Issues in Solid Oxide Cells During High Temperature Electrolysis

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
M. S. Sohal ◽  
J. E. O’Brien ◽  
C. M. Stoots ◽  
V. I. Sharma ◽  
B. Yildiz ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Potential ◽  
Contact Problems ◽  
Oxygen Electrode ◽  
Solid Oxide ◽  
Degradation Mechanisms ◽  
Electrolysis Cells ◽  
Post Test ◽  
Solid Oxide Electrolysis Cells ◽  
High Temperature Electrolysis

Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problems between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL’s test results on high temperature electrolysis (HTE) using solid oxide cells do not provide clear evidence of whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become nonconductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. Virkar and co-workers have developed a SOEC model based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic nonequilibrium. This model is under continued development. It shows that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, within the electrolyte. The chemical potential within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just under the oxygen electrode (anode)/electrolyte interface, leading to electrode delamination. This theory is being further refined and tested by introducing some electronic conduction in the electrolyte.

Spatially confined catalysis-enhanced high-temperature carbon dioxide electrolysis

2015 ◽  
Vol 17 (17) ◽  
pp. 11705-11714 ◽  
Author(s):  
Liming Yang ◽  
Xingjian Xue ◽  
Kui Xie
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Solid Oxide

Spatially confined catalysis significantly improves the CO2 electrolysis with Faraday efficiency above 90% in a solid-oxide electrolyzer with a TiO2 cathode.

Integrating Catalytic Coal Gasifiers With Solid Oxide Fuel Cells

2010 ◽  
Author(s):  
Nicholas Siefert ◽  
Dushyant Shekhawat ◽  
Thomas Kalapos
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
High Temperature ◽  
Solid Oxide Fuel Cells ◽  
Chemical Reactions ◽  
Steam Gasification ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Entrained Flow ◽  
Coal Gasifier

A review was conducted for coal gasification technologies that integrate with solid oxide fuel cells (SOFC) to achieve system efficiencies near 60% while capturing and sequestering >90% of the carbon dioxide [1–2]. The overall system efficiency can reach 60% when a) the coal gasifier produces a syngas with a methane composition of roughly 25% on a dry volume basis, b) the carbon dioxide is separated from the methane-rich synthesis gas, c) the methane-rich syngas is sent to a SOFC, and d) the off-gases from the SOFC are recycled back to coal gasifier. The thermodynamics of this process will be reviewed and compared to conventional processes in order to highlight where available work (i.e. exergy) is lost in entrained-flow, high-temperature gasification, and where exergy is lost in hydrogen oxidation within the SOFC. The main advantage of steam gasification of coal to methane and carbon dioxide is that the amount of exergy consumed in the gasifier is small compared to conventional, high-temperature, oxygen-blown gasifiers. However, the goal of limiting the amount of exergy destruction in the gasifier has the effect of limiting the rates of chemical reactions. Thus, one of the main advantages of steam gasification leads to one of its main problems: slow reaction kinetics. While conventional entrained-flow, high-temperature gasifiers consume a sizable portion of the available work in the coal oxidation, the consumed exergy speeds up the rates of reactions. And while the rates of steam gasification reactions can be increased through the use of catalysts, only a few catalysts can meet cost requirements because there is often significant deactivation due to chemical reactions between the inorganic species in the coal and the catalyst. Previous research into increasing the kinetics of steam gasification will be reviewed. The goal of this paper is to highlight both the challenges and advantages of integrating catalytic coal gasifiers with SOFCs.

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