A standard emergency shutdown procedure 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 (IGFC), 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 quantifying risk mitigation strategies.The previous implementation of facility emergency shutdown control strategies resulted in turbomachinery hardware failure, and would certainly have resulted in catastrophic failure of the fuel cell in the system. An analysis of system performance was completed to evaluate failure modes leading to the destruction of equipment. The primary linking event in these cases was compressor stall and surge resulting from the sudden loss of fuel during implementation of the standard double block and bleed strategy used in emergency shutdown. The implementation of this strategy and real-time communication is described in detail. Subsequently, a new mitigation strategy involving automated ramps is proposed for controlled emergency shutdown.
