NH3 Reformer for a SOFC System

Abstract

The NH3 dissociation performance of four commercially available catalysts, consisting of different Ni and Ru compositions, was tested. Therefore, ammonia was taken from a gas bottle and was alternately mixed with steam or was taken as pure NH3 gas, before it was sent through an electrically heated reformer. The reformer was developed and manufactured by the company AVL. Based on the residual NH3 concentration after the reformer and the temperature at the end of the reformer the different catalysts were compared to each other. The tests showed that Ni based catalysts had a better performance than Ru based catalysts in terms of NH3 dissociation under both moist and dry conditions. The desorption of the nitrogen atom from the catalyst surface was determined to be the reaction rate-limiting step. Furthermore, it was found that during moist measurements NO was built after the ammonia concentration fell below (0,8 ± 0,2) vol-% NH3.