Water-balance Assessment in a Reformer/Fuel-cell System

Abstract. In PEM fuel cells pure hydrogen is used as a fuel. Due to its low density, the density of its stored energy is low, too. One of the possible solutions to the problem is production of hydrogen from the energy-reach material, e.g. methanol. Conversion of methanol to hydrogen is made with reformer in a steam reforming process in which besides methanol there is also water needed. On the other hand, water is one of the products in the reaction between hydrogen and oxygen in fuel cells. The question we wanted to answer was what is the total water balance in a system consisting of a methanol reformer and a fuel-cellbased generator set and should water be supplied or removed from the system. The paper presents a model capable of assessing the water balance using some simple assumptions and commercial data from suppliers of fuel-cell systems and methanol reformers. The model shows that in normal states and by using a commercial reformer and a fuel-cell system, there is always a surplus of water present. With an example of a system consisting of the Genesis 20 LE Methanol Reformer and NexaTM Fuel-cell Power Module it is shown how the parameters for the water-balance model can be assessed.