Modeling of Molten Hydroxide Direct Carbon Fuel Cell – Effect of Carbonate Formation

Abstract

The utilization of energy continues to increase every year due to urbanization, population growth, and industrial activity. Conventional thermal power plants that operate on fossil fuels supply not less than 80 % of the world’s primary energy. To lessen the dependence of humans on conventional energy sources that are heavy carbon dioxide emitters, alternative energy generation methods such as Direct Carbon Fuel Cells (DCFC) can be developed during the transition to renewable energy. Direct carbon fuel cells have high overall system efficiency. No fuel pre-treatment is needed, and the emitted CO2 can be easily sequestered because it is concentrated and has high purity. However, the development of DCFC is still in its early stages, and further research must be done for DCFC to be available for commercial purposes. In this study, the effect of carbonate formation and reverse Boudouard reaction have been incorporated into the electrochemical model for molten hydroxide DCFC. The effect on the performance of the fuel cell is determined through the resulting power density and temperature profile. A power density of 0.0634 W/cm2 can be obtained at a current density of 0.2 A/cm2 from the power density curve. The voltage efficiency can be as high as 56 % at 923 K. The gas present in the anode may be considered to consist of only CO2 due to negligible CO formation, while carbonate formation is significant. An electrochemical and transport model of DCFC is necessary to compensate for the shortcomings of experimental data. In addition, mathematical modeling could be used to complement experimental results in optimizing the performance of DCFC.