Dispersion - An entropy generator of diffusion

In multicomponent gaseous flows with chemical reactions, diffusion is usually considered to be a single-source entropy generator. Introducing the concept of dispersion, where the atom balance is dominant rather than the molecular, shows in an ideal setting that, even when there is diffusion, the dispersion part of entropy generation can be reduced to Zero by proper choice of species flow velocities. Fuel cells and methane reformers are employed as examples to illustrate these concepts.