The Woodruff School

SUMMARY

Solid oxide fuel cell/gas turbine (SOFC/GT) hybrid systems harness the capability to operate nearly 15 to 20 percent more efficient than standard natural gas or pulverized coal power plants. Though the performance of these systems is quite promising, a number of system integration challenges, primarily with regards to thermal transport, still remain. Though pre-existing research efforts have attempted to address these challenges individually, the synergistic component of hybridization, which includes system balance of plant feedback as well as dynamic response, demands that these challenges be addressed in coupled manner for SOFC/GT hybrid systems. It is for that reason that the HyPer facility, a Hardware-in-the-Loop SOFC/GT hybrid simulator was built at the National Energy Technology Laboratory in Morgantown, WV. The HyPer facility couples an actual gas turbine with a combination of hardware and software that are used to simulate an actual SOFC. The facility is used to empirically address the system integration issues associated with fuel cell/gas turbine hybrids. Through this dissertation project, the software component of the SOFC simulator was upgraded from a 0-D lumped SOFC model to a 1-D, distributed, real-time operating SOFC model capable of spatio-temporal characterization of a fuel cell operating with a gas turbine in a hybrid arrangement. Once completed and verified, the upgraded HyPer facility was used to characterize the impact of cold air by-pass and initial fuel cell load on electrochemical start-up in an SOFC/GT hybrid environment. The impact of start-up on fuel cell inlet process parameters, SOFC performance and SOFC distributed behavior are presented and analyzed in comparative manner. This study presents the first time that an empirical parametric study, characterizing system operation during electrochemical start-up has been conducted. The results and findings of this study will be used to design control mechanisms for hybrid systems to ensure safe and reliable system operation during electrochemical start-up.

SUBJECT:	Ph.D. Dissertation Defense

BY:	Dimitri Hughes

TIME:	Tuesday, May 17, 2011, 3:00 p.m.

PLACE:	Love Building, 109

TITLE:	A Hardware-Based Transient Characterization of Electrochemical Start-Up In An SOFC/Gas Turbine Hybrid Environment Using a 1-D Real Time SOFC Model

COMMITTEE:	Dr. Comas Haynes, Co-Chair (GTRI/ME) Dr. William Wepfer, Co-Chair (ME) Dr. Samuel Graham (ME) Dr. Sheldon Jeter (ME) Dr. Meilin Liu (MSE) Dr. David Tucker (NETL)

SUMMARY Solid oxide fuel cell/gas turbine (SOFC/GT) hybrid systems harness the capability to operate nearly 15 to 20 percent more efficient than standard natural gas or pulverized coal power plants. Though the performance of these systems is quite promising, a number of system integration challenges, primarily with regards to thermal transport, still remain. Though pre-existing research efforts have attempted to address these challenges individually, the synergistic component of hybridization, which includes system balance of plant feedback as well as dynamic response, demands that these challenges be addressed in coupled manner for SOFC/GT hybrid systems. It is for that reason that the HyPer facility, a Hardware-in-the-Loop SOFC/GT hybrid simulator was built at the National Energy Technology Laboratory in Morgantown, WV. The HyPer facility couples an actual gas turbine with a combination of hardware and software that are used to simulate an actual SOFC. The facility is used to empirically address the system integration issues associated with fuel cell/gas turbine hybrids. Through this dissertation project, the software component of the SOFC simulator was upgraded from a 0-D lumped SOFC model to a 1-D, distributed, real-time operating SOFC model capable of spatio-temporal characterization of a fuel cell operating with a gas turbine in a hybrid arrangement. Once completed and verified, the upgraded HyPer facility was used to characterize the impact of cold air by-pass and initial fuel cell load on electrochemical start-up in an SOFC/GT hybrid environment. The impact of start-up on fuel cell inlet process parameters, SOFC performance and SOFC distributed behavior are presented and analyzed in comparative manner. This study presents the first time that an empirical parametric study, characterizing system operation during electrochemical start-up has been conducted. The results and findings of this study will be used to design control mechanisms for hybrid systems to ensure safe and reliable system operation during electrochemical start-up.