Electrochemical model of the integrated planar solid oxide fuel cell (IP-SOFC)

Costamagna, Paola; Selimovic, Azra; Borghi, Adriana Del; Agnew, Gerry

doi:10.1016/j.cej.2004.02.005

Cited by 273 publications

(161 citation statements)

References 7 publications

Supporting

Mentioning

157

Contrasting

Order By: Relevance

“…20 Several of the early SOFC electrochemistry models in literature are based on this assumption. [26][27][28][29][30][31][32] In this approach, the current density i is related to the cell voltage V cell according to Eq. 15.…”

Section: Modeling Methodologymentioning

confidence: 99%

Sulfur Poisoning of SOFCs: A Model Based Explanation of Polarization Dependent Extent of Poisoning

Janardhanan

Monder

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

Several experimental studies have shown that, 1) the extent of the poisoning effect due to trace amounts of sulfur compounds in the fuel is lower if a SOFC is operated at a higher current density, and 2) the performance drop due to sulfur poisoning is much lower for Ni-GDC or Ni-ScSZ anodes when compared to Ni-YSZ anodes. This work presents a first principles numerical model that simulates experimental studies of sulfur poisoning on SOFC button cells. The exchange current densities for the electrodes are determined using sulfur-free polarization data for cells fueled by humidified mixtures of H 2 and N 2 . A detailed surface reaction model that predicts the fractional coverage of all adsorbed species at the three phase interface is coupled to the SOFC model and the sulfur coverage is used to alter the anode exchange current density. The resulting model predictions match experimental observations during both galvanostatic and potentiostatic operation. Our analysis shows that the observed lower performance drop at higher current density is due to the non-linear nature of the electrochemical rate equations, and that the lower impact of sulfur poisoning on Ni-GDC and Ni-ScSZ anodes (compared to Ni-YSZ anodes) is due to their higher electrochemical activity. Solid oxide fuel cell (SOFC) systems operating on natural gas or gasified coal can be significantly more energy efficient than today's combustion systems and can thus reduce CO 2 emissions. However, a major problem associated with the use of hydrocarbon fuels is the presence of sulfur containing compounds that are converted to H 2 S under SOFC operating conditions.1 The H 2 S present in the feed gas can readily deactivate conventional Ni cermet anodes. One can certainly have a desulfurization unit before the fuel cell stack to deal with the sulfur poisoning. However, this leads to increased system complexity and decrease in overall efficiency. Nevertheless, it is important to understand and quantify the sulfur tolerance of SOFC anodes in the event of sulfur breakthrough from the desulfurizer. Sulfur poisoning of Ni-YSZ anodes in SOFC is well studied experimentally for model fuel compositions consisting of ppm levels of H 2 S in mixtures of H 2 , H 2 O and an inert 2-4 as well as H 2 S in gas mixtures representative of natural gas or reformed natural gas.5-8 Most of the experimental literature deals with H 2 S concentrations well below 10 ppm and work that treats H 2 S concentrations higher than 20 ppm is rather limited. 2,5,8 On the other hand it is well known that natural gas and biogas can have substantially higher sulfur concentrations and that catalytic steam reforming of methane can be carried out on Ni even with 100 ppm H 2 S without losing all catalytic activity 9,10 e.g., a methane conversion (in model biogas) of ∼35% can be maintained using a supported Ni catalyst with 100 ppm H 2 S at 800• C. 10For an electrolyte supported cell Zha et al., 2 studied the cell performance for a wide range of H 2 S concentrations using DC polarization and electrochemical i...

show abstract

Section: Modeling Methodologymentioning

confidence: 99%

Sulfur Poisoning of SOFCs: A Model Based Explanation of Polarization Dependent Extent of Poisoning

Janardhanan

Monder

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…The values of the resistivities of all materials except for the cathode were modeled as temperaturedependent, again following the values formulated in [34]. The current work assumes an anode-supported cell; thus, the thicknesses modeled in this work were as follows:…”

Section: Sofc Subsystem Modelmentioning

confidence: 99%

“…The thermodynamics process utilizes standard expressions of voltage related to current density and electrochemical losses modeled after the work of Costamagna et al [34]. The output of this process was the current density based on a set of given conditions within the node and the voltage passed to the process from the system controller.…”

Section: Sofc Subsystem Modelmentioning

confidence: 99%

Feasibility study for SOFC-GT hybrid locomotive power part II. System packaging and operating route simulation

Martinez

Brouwer

Samuelsen

2012

Journal of Power Sources

View full text Add to dashboard Cite

a b s t r a c tThis work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonable dynamic response. The use of diesel fuel reformate in the SOFC presents a challenge to the electrochemistry, especially as it relates to control and optimization of the fuel utilization in the anode compartment. This is found to arise from the large amount of carbon monoxide in diesel reformate that is fed to the fuel cell, limiting the maximum fuel utilization possible. This presents an opportunity for further investigations into carbon monoxide electrochemical oxidation and/or system integration studies where the efficiency of the fuel reformer can be balanced against the needs of the SOFC.

show abstract

“…In other concepts (e.g. the integrated planar or segmented in series design of Rolls-Royce Fuel Cell Systems [4]) the substrate is effectively rigid. In such cases the electrolyte layer is fully constrained in its plane during sintering and shrinkage only occurs perpendicular to this plane (except within a distance of a few layer thicknesses of the layer edges).…”

Section: Introductionmentioning

confidence: 99%