Technology Management and Analysis of Integrating Fuel Cell Systems in Gas Turbine Power Plants

Abstract

In this thesis, comprehensive and detailed energy and economic analyses of integrating different types of fuel cells in gas turbine power plants are performed. The research investigates the performance of a hybrid system that consists of solid oxide fuel cells (SOFC) combined with a proton exchange membrane fuel cells (PEMFC) integrated into a gas turbine power plant. Detailed modeling including thermodynamic, kinetic, and geometric models are developed, implemented and validated for the synthesis/design and operational analysis of the combined hybrid system. In the proposed system, the PEMFC makes use of the internal reforming ability of the SOFC to produce hydrogen which is necessary for the PEMFC operation. A detailed comparative study between the proposed system and other conventional or SOFC integrated systems is also conducted. The comparative study includes performing a complete technical and economic study for each of the proposed systems which are the conventional gas turbine cycle, the SOFC-gas turbine integrated cycle (SOFC-GT), and the PEMFC, SOFC and gas turbine integrated cycle. Different levels of modeling for the SOFC, the PEMFC and the integrated system are presented. The study also includes applying different methods and techniques to enhance the efficiency of the proposed cycle. The efficiency of the plant is studied by varying several parameters including operating pressure for the SOFC-GT system, temperatures of the fuel and the air, and the mass flow rates of air and fuel. Energy and entropy balances are performed not only for the overall systems but also for each component of the systems to evaluate performance of each system in addition to the distribution of irreversibility and thermodynamic inefficiencies. Furthermore, a detailed exergy analysis is conducted for each of the proposed systems under investigation. This analysis is achieved by calculating the exergy destruction and exergetic efficiency for each component in each of the investigated systems. Finally, the analysis also shows detailed calculations of the overall second law efficiency as well as detailed economic analysis of the proposed integrated systems. Keywords: Gas Turbine Power Plant, PEM fuel cell, SOFC, Exergetic Efficiency, Thermal Efficiency, Economic Analysis, Technology Management.