Secondary thermodynamics courses study advanced energy cycles. They have also started to include some introduction to fuel cell operation. Seemingly difficult, the fuel cell concepts can naturally be drawn from the topics of chemical equilibrium, which are also introduced in these courses for chemical reactions and combustion. The Nernst equation, a cornerstone of fuel cell operation, is based on a change of the Gibbs energy in a non-equilibrium fuel cell reaction. The resulting terms in the Nernst equation include the concentrations of the reactants, which dynamically change as the fuel and oxidizer deplete in the reaction while flowing through the cell. This becomes particularly interesting in high temperature fuel cells that incorporate fuel reforming and fuel utilization into a single system. The introduced fuel cell project proposes to combine the chemical equilibrium and non-equilibrium concepts simultaneously coexisting in a high temperature fuel cell. Relatively low operational temperatures allow for a simplified chemical equilibrium analysis of the fuel flowing in the fuel cell while superimposing it on the fuel cell reaction and fuel/oxidizer utilization. The variety of fuel and oxidizer mixtures, operating temperatures and pressures allows for creating a large number of individualized assignments. Students will benefit from a project that reinforces their understanding of fuel cell performance while increasing their comfort with chemical equilibrium concepts.
Chemical equilibrium analysis for hydrolysis of magnesium hydride to generate hydrogen
