A finite element analysis modeling tool for solid oxide fuel cell development: coupled electrochemistry, thermal and flow analysis in MARC®

Khaleel, Mohammad A.; Lin, Zijing; Singh, Prabhakar; Surdoval, Wayne A.; Collin, D

doi:10.1016/j.jpowsour.2003.11.074

Cited by 144 publications

(67 citation statements)

References 4 publications

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“…The effect of carbon monoxide on electro-chemical potential is neglected since water-gas shift chemistry is much faster than CO electro-oxidation in the high temperature fuel cell of interest. Studies have found that as much as 98% of the CO reacts via this route (shift reaction followed by H 2 electro-oxidation) in an SOFC [14]. Note that pressure in the anode and cathode compartments are assumed to be the same.…”

Section: Operating Cell Voltagementioning

confidence: 99%

Power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system

Kaneko

Brouwer

Samuelsen

2006

Journal of Power Sources

101

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Power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system AbstractThis paper addresses how the power and temperature are controlled in a biomass gas fueled solid oxide fuel cell (SOFC) and micro gas turbine (MGT) hybrid system. A SOFC and MGT dynamic model are developed and used to simulate the hybrid system performance operating on biomass gas. The transient behavior of both the SOFC and MGT are discussed in detail.An unstable power output is observed when the system is fed biomass gas. This instability is due to the fluctuation of gas composition in the fuel. A specially designed fuel controller succeeded not only in allowing the hybrid system to follow a step change of power demand from 32 to 35 kW, but also stably maintained the system power output at 35 kW. In addition to power control, fuel cell temperature is controlled by introduction and use of a bypass valve around the recuperator. By releasing excess heat to the exhaust, the bypass valve provided the control means to avoid the self-exciting behavior of system temperature and stabilized the temperature of SOFC at 850• C.

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Section: Operating Cell Voltagementioning

confidence: 99%

Power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system

Kaneko

Brouwer

Samuelsen

2006

Journal of Power Sources

101

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“…The PNNL developed SOFC-MP code solves the equations for mass transport, energy, and electrochemistry required to predict the fluid flow, temperature, species, and current density distributions in a three-dimensional SOFC geometry. 2,3,4 The electrochemistry model used was described by Chick et al, 5 calibrated 6,7 for application to planar stack simulations, and updated to provide an improved anode concentration polarization model. 8 The capabilities of these tools have also been expanded to incorporate steam-methane reformation for simulating on-cell reforming 9 and have been updated with a rate expression derived experimentally at PNNL:…”

Section: Methodsmentioning

confidence: 99%

Analysis of Percent On-Cell Reformation of Methane in SOFC Stacks: Thermal, Electrical and Stress Analysis

Recknagle¹,

Yokuda²,

Jarboe³

et al. 2006

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Executive SummaryThis report summarizes a parametric analysis performed to determine the effect of varying the percent on-cell reformation (OCR) of methane on the thermal, electrical, and mechanical performance for a generic, planar solid oxide fuel cell (SOFC) stack design. OCR of methane can be beneficial to an SOFC stack because the reaction (steam-methane reformation) is endothermic and can remove excess heat generated by the electrochemical reactions directly from the cell. The heat removed is proportional to the amount of methane reformed on the cell. Rapid reaction kinetics provided by the high-temperature SOFC operation and excess steam over the nickel-based anode catalyst ensure complete methane conversion. Thus, the thermal load varies with methane concentration entering the stack. The endotherm due to the fast reformation reaction can cause a temperature depression on the anode near the fuel inlet, resulting in large thermal stresses. This effect depends on factors that include inflowing methane concentration, local temperature, and stack geometry.The analysis assumed the fuel would be partially to fully pre-reformed in an external reformer such that the desired fuel compositions would be delivered to the stack, where the remaining percentage of the reformation reaction would be completed on-cell. Simulations were performed using an SOFC stack modeling tool developed at PNNL and validated for the prediction of fuel use, on-cell methane reforming, and distribution of temperature. The study was performed using three-dimensional stack model geometries. Cross-flow, co-flow, and counter-flow configuration stacks of 10x10-and 20x20-cm cell sizes were examined. Thermal performance was evaluated based on the predicted maximum temperature difference on the anode. Electrical performance was based on the predicted power output. Mechanical performance was based on the maximum principal stress on the anode. Fuel utilization was established at 75%. The effect of cathode air cooling was included in the study by examination of 30% and 15% air utilizations.The analysis showed for the counter-flow and cross-flow stacks of 10x10-cm size the stress and temperature difference would be minimized when between 40 and 50% of the reformation reaction occurred on the anode. Gross electrical power density was virtually unaffected by %OCR. For all stack configurations and sizes the inflow temperature increased with %OCR as the subsequent heat load decreased. Cooling provided by the cathode airflow associated with 30% air utilization was not substantially improved upon by 15% air use for the smaller (10x10-cm) stack size. The increased airflow associated with 15% air utilization was needed for cooling the larger (20x20-cm) stacks. The co-flow stack exhibited the largest benefit from the additional cathode air cooling and had the lowest anode stresses of the 20x20-cm stacks. For the conditions and particular generic stacks of this study, the results suggest 40 to 50% OCR should be considered for cross-flow and counter-flow stacks, ...

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“…As a result, a requirement exists for sophisticated numerical methods capable of simulating the performance of a SOFC over a broad range of design and operating parameters [11,12]. Accordingly, this study constructs a 3-D model of a tubular, anode-supported SOFC using commercial finite volume software (CFD-RC) and solves the governing equations for the gas flows within the fuel cell using a finite volume method.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation into Thermofluidic and Electrochemical Characteristics of Tubular‐type SOFC

Kuo

2010

Fuel Cells

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Three‐dimensional simulations based on a multi‐physics model are performed to examine the thermofluidic and electrochemical characteristics of a tubular, anode‐supported solid oxide fuel cell (SOFC). The simulations focus on the local transport characteristics of the cathode and anode gases and the distribution of the temperature field within the fuel cell. In addition, the electrochemical properties of the SOFC are systematically examined for a representative range of inlet gas temperatures and pressures. The validity of the numerical model is confirmed by comparing the results obtained for the correlation between the power density and the current density with the experimental results presented in the literature. Overall, the present results show that the performance of the tubular SOFC is significantly improved under pressurised conditions and a higher operating temperature.

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A finite element analysis modeling tool for solid oxide fuel cell development: coupled electrochemistry, thermal and flow analysis in MARC®

Cited by 144 publications

References 4 publications

Power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system

Power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system

Analysis of Percent On-Cell Reformation of Methane in SOFC Stacks: Thermal, Electrical and Stress Analysis

Numerical Investigation into Thermofluidic and Electrochemical Characteristics of Tubular‐type SOFC

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