Investigation of a hybrid solar thermochemical water-splitting hydrogen production cycle and coal-fueled molten carbonate fuel cell power plant

Abstract

Increasing electricity demand in the world’s energy portfolio and the focus on reducing carbon emission footprints has led to broad research into flexible and efficient energy conversion systems. The integration of various energy conversion systems is an efficient approach to meet sustainable energy technologies’ demand in the future. In this study, a brainchild integration process of the solar thermochemical water-splitting hydrogen production cycle and coal-fueled molten carbonate fuel cell coupled with a gas turbine is proposed, modeled, and simulated in AspenTech v9.1. The Zinc/Zinc-oxide thermochemical cycle directly utilizes the solar high-temperature reactor thereby avoiding the need for non-renewable power, thus increasing the efficiency of the system. The molten carbonate fuel cell feeds on the syngas produced by the coal gasification and the oxygen and hydrogen of the thermochemical cycle. The heat of the fuel cell is further exploited by a gas turbine. A sensitivity analysis is conducted to appraise cardinal parameters on system performance indicating the fuel cell pressure, voltage, and current density as the most influential parameters. The concentrated solar power provides 5.88 MW of heat for the thermochemical cycle encompassing 434 parabolic dishes. The molten carbonate fuel cell has a 63% and 61% LHV and HHV efficiency, respectively, and the system has a total efficiency of approximately 85%, producing 13.63 MW of electricity.