The effect of coal thermal pretreatment on the electrochemical performance of molten hydroxide direct carbon fuel cell (MH-DCFC)

Abstract

The direct carbon fuel cell (DCFC) is a power generation device that converts the chemical energy of carbonaceous fuels (e.g. fossil coals, charred biomass, activated carbons, graphite, coke, carbon black, etc.) directly into electricity. However, the use of coal in the DCFC is sometimes problematic particularly if volatile matter evolves from the fuel during fuel cell operation.The recommended course of action to minimize that problem is to pre treat thermally or even pyrolyze the coal and remove the volatiles before the fuel is used in the fuel cell. In this paper, three raw and thermally-treated coals of various origins have been compared for electrochemical activity in a direct carbon fuel cell with molten hydroxide electrolyte (MH-DCFC). The thermal pre-treatment of selected coals was carried out in an inert gas atmosphere at 1023 K. It was found that—compared to raw coals—the pyrolyzed coals presented lower maximum current and power densities at 723 K but simultaneously provided faster stabilization of the open circuit voltage.