Semester

Summer

Date of Graduation

2012

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Bruce S. Kang.

Abstract

Direct utilization of coal syngas in solid oxide fuel cells (SOFCs) can potentially be an efficient technology for next generation clean power generation. Long-term durability is an important requirement for the application of SOFC technology. The useful working life of SOFCs depends on the material degradation which is due to the aggressive environment at the operating conditions. In addition to the electrochemical performance, the mechanical integrity of the fuel cell anode is also essential for successful long-term operation.;Material degradation may occur due to several mechanisms depending on the environment and loading conditions. It is reported that SOFC anodes are susceptible to the attack of coal syngas contaminants (such as S, P, As, etc), which can degrade the electrochemical performance and structural integrity of electrode materials. The SOFC anodes are also subjected to stresses at high temperature, thermal/redox cycles effects during long-term operation. In order to identify such degradation mechanisms and to determine the effects of those mechanisms on the long-term operation of SOFCs, a powerful in-situ test technique that can provide structural and electrochemical details under conditions of actual fuel cell operation is extremely attractive and necessary.;The goal of this research is to develop an enabling technology that integrates Sagnac interferometry and infrared thermometry for in-situ anode surface deformation, electrode surface reaction investigation and surface temperature measurement for SOFCs. The experimental results obtained under different operating conditions, such as hydrogen, simulated coal syngas, with or without trace contaminants (e.g. P) are utilized to validate and develop SOFC electrochemical and structural models for long-term prediction of the SOFC integrity under the operating conditions. The experimental setup developed in this research, is also utilized to estimate the material parameters for an SOFC anode material durability model, which incorporates thermo-mechanical and fuel gas contaminants degradation mechanisms, to predict the long-term structural integrity of SOFC anodes.

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