Molten carbonate direct carbon fuel cell systems and methods

There is described a direct carbon fuel cell system. The system includes fuel cells, each fuel cell having a porous fuel cell anode and a fuel cell cathode. The system further includes a molten carbonate electrolyte and a fuel supply apparatus for flowing a fuel slurry having carbon particles and a carbon carrier fluid to the fuel cell anodes in parallel. The carbon carrier fluid has a same composition as the molten carbonate electrolyte. An oxidant supply apparatus flows an oxygen-containing stream to the fuel cell cathodes in parallel. An electrolyte circulation apparatus circulates the molten carbonate electrolyte in contact with each of the fuel cells. During operation of the direct carbon fuel cell system to generate electric power, carbon is oxidized at the fuel cell anodes to produce carbon dioxide, and at the fuel cell cathodes oxygen and carbon dioxide react to produce carbonate ions.