Development of molten carbonate fuel cell based on lignin fuel consumption (MC-LFC): correlation between modeling and experimental results

COMSOL software was used for the modeling of the performance parameters of the Molten Carbonate – Lignin Fuel Cell (MC-LFC), as it is a flexible tool, able to handle different physical approaches. The model developed includes the following processes: electronic and ionic charge balance (Ohm's law), Butler- Volmer charge transfer kinetics, diffusion gas flow in porous electrodes (Brinkman’s equation), gas-phase mass balances in fuel and oxygen distribution channels, and porous electrodes (Maxwell-Stefan diffusion and convection). A parametric analysis was performed to evaluate the effect of material properties, pressure, and temperature, on cell performance. The results show that for a better performance of the MC-LFC cell, the exchange current density (A/m²) in the anode and cathode compartment must be respected in the interval [0.075, 0.75] and [1.58, 15.8]. The electrical conductivity of the electrolyte (S/m), anodic and cathodic materials can be respectively in the interval [26, 265], [25, 250], and [19, 60]. It is also noted that the increase in temperature from 700 K to 1000 K generates a drop in the maximum power density of the battery (approximately 1500 mW/cm² to 1260 mW/cm²). It is in every interest to operate the Cell MC-LFC under 500 °C.