Improving clean electrical power generation: A theoretical modelling analysis of a molten sodium hydroxide direct carbon fuel cell with low pollution

Traditional coal-fired-plants release large amounts of pollutants and have low efficiency. A molten hydroxide direct carbon fuel cell (MHDCFC) that directly converts the chemical energy into electricity with pure CO2 product is a potential clean power in the future. Low temperature and clean scaled-up operations are challenges for a MHDCFC. In this study, temperature, active specific surface area, fuel mass, and fuel type are studied through a model because they may significantly influence the cell performance by polarizations. When the active specific surface areas of graphite, activated carbon, and carbon black are 100 m2/m3, 1500 m2/m3, and 1500 m2/m3, respectively, the differences between the highest power density and other two power densities of the MHDCFCs powered by the three fuels reduce with decreasing temperature. Low temperature increases polarizations. The ratio of activation polarization to ohmic polarization is greater than 1/2 when the active specific surface area decreases to 100 m2/m3 at 623 K. A continuous increase in active specific surface area to 700 m2/m3 may cause decreases in amounts of activation polarization and toxic chemicals used in fuel processing, simultaneously. Large fuel mass and weak conductivity of a fuel weaken the cell performance by increasing ohmic polarization at low temperatures. The MHDCFC is governed by activation and ohmic polarizations. The model may balance an increase in polarizations, an increase in invalid CO2 and a decrease in volatile amount of corrosive electrolyte at low temperatures and scaled-up levels for a clean and efficient electricity generation.