Analysis of a hybrid molten carbonate fuel cell and gas turbine cycle.

Abstract

Background: Hybrid systems with fuel cells and thermal engines are studied with promising results. Molten carbonate fuel cells (MCFC) show many advantages compatible with the current demands for energy production in a sustainable competitive way. Materials and Methods: This paper focuses on the computational investigation of an indirect internal reforming MCFC coupled to a gas turbine (GT) system. The technical analysis comprises of energy analysis of the hybrid cycle, using the Gibbs function minimization technique for the methane steam reforming process. The assessment is performed to determine the influence of the hybrid cycle operating temperature and pressure, steam-to-carbon ratio, and fuel and oxidant usage in the fuel cell. Results: Results show that the increase in temperature and in operating pressure of the fuel cell and the fuel reform rate improves the hybrid system performance. Variation in the utilization factor, however, did not determine an expressive increase in system efficiency. For the same fuel mass flow rate, it is possible to see that the variation in the operating temperature of the fuel cell resulted in an increase in the total power of the hybrid system when compared to the results of the pressure increase. The increase in temperature resulted in a maximum increase of 12% in delivered power and corresponding to about 7% system efficiency increase. Instead, an increase in pressure of about 4% corresponding to an increase of about 2% system efficiency. Conclusion: Although an increase in the fuel cell's power density was observed for the same mass flow rate in the system, the pressure negatively influenced the total delivered power by the fuel cell.