Using inlet guide vane to improve load following ability of solid oxide fuel cell and gas turbine hybrid cycle

Fuel Cell is widely regarded as a potential alternative in the electric utility due to its distinct advantages of high energy conversion efficiency, low environmental impact and flexible uses of fuel types. In this paper we demonstrate the enhancement of thermal efficiency and power density of the power plant system by incorporating a hybrid cycle of Solid Oxide Fuel Cell (SOFC) and gas turbine with appropriate configurations. In this paper, a hybrid system composed of SOFC, gas turbine, compressor and high temperature heat exchanger is developed and simulated in the Virtual Test Bed (VTB) computational environment. The one-dimensional tubular SOFC model is based on the electrochemical and thermal modeling, accounting for the voltage losses and temperature dynamics. The single cell is discretized using a finite volume method where all the governing equations are solved for each finite volume. Simulation results show that the SOFC-GT hybrid system could achieve a 70% total electrical efficiency (LHV) and an electrical power output of 853KW, around 30% of which is produced by the power turbine. Two conventional power plant systems, i.e. gas turbine recuperative cycle and pure Fuel Cell power cycle, are also simulated for the performance comparison to validate the improved performance of Fuel Cell/Gas Turbine hybrid system. Finally, the dynamic behavior of the hybrid system is presented and analyzed based on the system simulation.

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Performance Evaluation of Solid Oxide Fuel Cell Engines Integrated With Single/Dual-Spool Turbochargers

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4004471 ◽

2011 ◽

Vol 8 (6) ◽

Cited By ~ 3

Author(s):

So-Ryeok Oh ◽

Jing Sun ◽

Herb Dobbs ◽

Joel King

Keyword(s):

Fuel Cell ◽

Solid Oxide Fuel Cell ◽

Gas Turbine ◽

Gas Turbines ◽

Control Strategies ◽

Solid Oxide ◽

Oxide Fuel ◽

Operating Characteristics ◽

Load Following ◽

Fuel Flow

This study investigates the performance and operating characteristics of 5kW-class solid oxide fuel cell and gas turbine (SOFC/GT) hybrid systems for two different configurations, namely single- and dual- spool gas turbines. Both single and dual spool turbo-chargers are widely used in the gas turbine industry. Even though their operation is based on the same physical principles, their performance characteristics and operation parameters vary considerably due to different designs. The implications of the differences on the performance of the hybrid SOFC/GT have not been discussed in literature, and will be the topic of this paper. Operating envelops of single and dual shaft systems are identified and compared. Performance in terms of system efficiency and load following is analyzed. Sensitivities of key variables such as power, SOFC temperature, and GT shaft speed to the control inputs (namely, fuel flow, SOFC current, generator load) are characterized, all in an attempt to gain insights on the design implication for the single and dual shaft SOFC/GT systems. Dynamic analysis are also performed for part load operation and load transitions, which shed lights for the development of safe and optimal control strategies.

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