Modeling of CO2 Gasification of Carbon for Integration with Solid Oxide Fuel Cells

This modeling study focuses on gasification of carbon by CO2 in a minimally fluidized bed containing a solid oxide fuel cell (SOFC). Kinetic parameters for a five-step reaction mechanism characterizing the Boudouard reaction (C + CO2 -> 2CO) were determined thermogravimetrically at 1 atm from 973 to 1273 K. Experimentally determined kinetic parameters are employed in a transport model that predicts velocities and gas concentration profiles established in the carbon bed as a consequence of convection, diffusion, and heterogeneous reaction. The model is used to simulate the effect of an imbedded SOFC, in contact with the carbon bed. Although the model does not assume particular I-V characteristics for the fuel cell, it indicates that current densities in the practical range of 100-1000 mA/cm(2) can be supported. Results show that temperature strongly affects the current density, whereas CO2 flow I-ate has only a weak effect. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 983-992, 2009