Study of Water Gas Shift Reaction over Ceria Based Catalysts in Solid Oxide Fuel Cells

2015 ◽  
Vol 68 (1) ◽  
pp. 1207-1217 ◽  
Author(s):  
P. Tepamatr ◽  
E. Buarod ◽  
N. Laosiripojana ◽  
S. Charojrochkul
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Water Gas Shift ◽  
Oxide Fuel ◽  
Water Gas Shift Reaction ◽  
Shift Reaction ◽  
Water Gas

Numerical Analysis of the Internal Fuel Processing in Solid Oxide Fuel Cells

2013 ◽  
Author(s):  
Ernesto De La Pena-Cortes ◽  
Francisco Elizalde-Blancas ◽  
Abel Hernandez-Guerrero ◽  
Armando Gallegos-Munoz ◽  
Juan M. Belman-Flores
Keyword(s):  
Chemical Kinetics ◽  
Steam Reforming ◽  
Solid Oxide ◽  
Cell Performance ◽  
Water Gas Shift ◽  
Oxide Fuel ◽  
Water Gas Shift Reaction ◽  
Internal Reforming ◽  
Shift Reaction ◽  
Water Gas

The high operating temperature of a SOFC (solid oxide fuel cell) has several consequences, from which the most important one is the possibility to feed the cell directly with unprocessed fuels. This eliminates the need for expensive external fuel reformers that hinder the cell from achieving a greater overall efficiency when coupled into a power generation system. Direct internal reforming (DIR) takes place directly on the anode of a SOFC by harnessing the available Nickel catalyst on its surface to process the incoming fuel. In this study a three dimensional steady state computational fluid dynamics model is implemented in a planar DIR SOFC to compare the overall cell performance operating on biogas, and coal syngas. Since chemical kinetics plays a significant role in the model accuracy, the present work also focuses on comparing three different chemical reaction mechanisms for the internal reforming process. These include a detailed heterogeneous mechanism consisting of 42 elementary reactions, a global homogeneous catalyzed mechanism, and a Langmuir-Hinshelwood based mechanism. The former includes autothermal reforming, steam reforming and water gas shift reaction effects, the latter two include steam reforming, and water gas shift reaction effects. The analysis yields detailed information about the cell, including polarization curves that help to assess the cell performance for each fuel. Meanwhile the chemical kinetics comparison amongst the analyzed mechanisms helps in establishing the best compromise between the accuracy of the model, and the computational resources devoted for the calculation.

Copper-Based Mixed Oxides Catalyst of Water-Gas Shift Reaction for Fuel Cells: The Role of Alkali Charge

2012 ◽  
Vol 268-270 ◽  
pp. 538-541
Author(s):  
Ke Duan Zhi ◽  
Quan Sheng Liu ◽  
Run Xia He ◽  
Fang Wu ◽  
Ya Gang Zhang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Surface Area ◽  
Mixed Oxides ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Catalyst Structure ◽  
Catalytic Behavior ◽  
Shift Reaction ◽  
Water Gas

The effects of alkali charge on the activity and stability of copper-based mixed oxides catalyst for the water-gas shift reaction (WGSR) were investigated. Activity tests showed that the copper-based mixed oxides catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 displayed higher activity and better stability than that of others catalysts. The BET , XRD and TPR results revealed that the Cu-Mn catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 led to higher surface area, a more stable catalyst structure and suitable reduction performance, in turn leading to better catalytic behavior for the Cu-Mn catalyst.

An Analytical Study of Diffusion, Chemical Reaction and Voltage Loss in High-Temperature Solid Oxide Fuel Cells

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
John B. Young
Keyword(s):  
High Temperature ◽  
Solid Oxide Fuel Cells ◽  
Chemical Reaction ◽  
Cell Voltage ◽  
Solid Oxide ◽  
Water Gas Shift ◽  
Oxide Fuel ◽  
Voltage Loss ◽  
Water Gas ◽  
Non Equilibrium

The paper describes a mathematical analysis of multi-component diffusion with chemical reaction in the porous materials of high-temperature solid oxide fuel cells. The objectives are to clarify the underlying physics, to investigate different modeling approaches and to establish expressions for the cell voltage loss. The description proceeds from the simplest non-reactive binary diffusion process, through a multi-component analysis with non-reactive diluent gases present, to diffusion in the presence of the water-gas shift chemical reaction. Using a single average diffusion coefficient, an analytical solution can be found, not only for the limiting cases of frozen and equilibrium water-gas shift chemistry but also for the general non-equilibrium situation. A Damköhler number is identified and it is shown that shift equilibrium is not necessarily preserved in the anode flow. The non-equilibrium analysis also reveals unusual behavior whereby the molar fluxes become discontinuous in the equilibrium limit while the mole fractions and cell voltage loss approach the limit continuously. A physically more realistic model based on two diffusion coefficients provides a more detailed description for frozen and equilibrium chemistry but does not yield an explicit non-equilibrium solution. In all, the analysis provides fundamental insight and quantitative predictions for many of the flow phenomena occurring in the porous materials of SOFCs.

Effect of an Anode Functional Layer on Cell Performance of Anode-Supported Solid Oxide Fuel Cells by a Decalcomania Method

2013 ◽  
Vol 51 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Sun-Min Park ◽  
Hae-Ran Cho ◽  
Byung-Hyun Choi ◽  
Yong-Tae An ◽  
Ja-Bin Koo ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Cell Performance ◽  
Oxide Fuel ◽  
Functional Layer
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