A pressure drop analysis for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle, implemented through the hybrid performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test, and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide means of evaluating risk mitigation strategies. The cold-air bypass in the Hyper facility directs compressor discharge flow to the turbine inlet duct, bypassing the fuel cell, and exhaust gas recuperators in the system. This valve reduces turbine inlet temperature while reducing cathode airflow, but significantly improves compressor surge margin. Regardless of the reduced turbine inlet temperature as the valve opens, a peak in turbine efficiency is observed during characterization of the valve at the middle of the operating range. A detailed experimental analysis shows the unusual behavior during steady state and transient operation, which is considered a key point for future control strategies in terms of turbine efficiency optimization and cathode airflow control.
Control Impacts of Cold-Air Bypass on Pressurized Fuel Cell Turbine Hybrids
Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF FUEL CELL SCIENCE AND TECHNOLOGY. Manuscript received August 19, 2014; final manuscript received October 24, 2014; published online December 2, 2014. Editor: Nigel M. Sammes.This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. Approved for public release; distribution is unlimited.
Pezzini, P., Celestin, S., and Tucker, D. (February 1, 2015). "Control Impacts of Cold-Air Bypass on Pressurized Fuel Cell Turbine Hybrids." ASME. J. Fuel Cell Sci. Technol. February 2015; 12(1): 011006. https://doi.org/10.1115/1.4029083
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