A Comprehensive Analysis Procedure for Predicting the Performance of a Molten Carbonate Fuel Cell

A three-dimensional numerical procedure to predict the performance of a molten carbonate fuel cell has been developed. The Navier-Stokes, energy, and species equations are solved to obtain the velocity, temperature, pressure, and concentration distributions in the cathode/ anode channel. The channel with the trapezoidal supports is approximated by an anisotropic porous medium, of which the effective permeability and conductivity are obtained by separate 3D FVM calculations. For a given average current density, the local current density, which is directly related to the rate of chemical reaction and heat generation on the reaction surface, and the cell voltage are determined to satisfy the electrochemical relations at the electrode surface. The process is iterative and the solution is assumed to have converged when the cell voltage and the local current density fall within the specified convergence limits. The unit cell characteristics, such as current-density distribution, and average current density vs. cell voltage are presented and discussed. Once the relation between the flow rate and the pressure loss in a unit cell are known, the mass flow to each cell of a MCFC stack is estimated by coupling the manifold flow and the flow within the unit cell. The stack performance is then calculated by integrating the individual cell performance using this information.