Session: 06-04 Fuel Cell Driven Cycles I

Paper Number: 126860

126860 - Development and Optimization of a Solid Oxide Fuel Cell Gas Turbine Hybrid System 

Solid Oxide Fuel Cells (SOFC) are an advanced form of fuel cells which are capable of converting hydrocarbon based fuels into electricity at efficiencies reaching 60%. Fuel efficiency can be increased to 70% or higher by closely integrating an SOFC into the hot gas path of a Brayton cycle gas turbine. SOFCs, unlike more common low temperature fuel cell technologies such as PEM and Alkaline, operate at elevated temperatures between 500-1,000C. These temperatures are well suited for integration into microturbines and other smaller class gas turbines.

Integration of SOFCs into gas turbines yields a system with efficiency and performance characteristics greater than either of the systems on their own. Fuel efficiency is enhanced through several mechanisms including operating the SOFC at elevated pressure by placing the SOFC between the gas turbine’s compressor and expander. By using the gas turbine’s combustor to oxidize dilute fuel remaining in the anode tailgas further lifting the already pressurized and hot cathode tailgas’s temperature before expanding it through a turbine creating additional power. And by eliminating much of the parasitic balance-of-plant (BOP) required to preheat and circulate air through the SOFC. Performance is enhanced by utilizing the gas turbine to respond to fluctuating power demands much more quickly than an SOFC is capable of and utilizing the gas turbine to start the SOFC without additional BOP.

The authors are part of a multi-company collaboration to develop and demonstrate a novel SOFC/GT system with 70%+ fuel to electrical conversion efficiency. This paper covers the system’s development with a specific focus on trade-offs and optimizations throughout the system architecture as well as the relative sizing and power split between SOFC and GT subsystems. The paper then covers control strategies developed for the SOFC/GT system and evaluated using Model-in-the-Loop and Software-in-the-Loop techniques. Finally, this paper covers the current status of the SOFC/GT system development and subsystem commissioning on physical hardware. 

Presenting Author: Michael Sprengel Czero

Presenting Author Biography: Mike Sprengel leads the Modeling and Simulation team at Czero and specializes in dynamic system modeling and supervisory control strategy development with a specific emphasis on accelerating the development and deployment of clean energy technologies.

Authors:

Michael Sprengel Czero
Nick Echter Czero