Analysis of the energy efficiency of innovative ATR-based PEM fuel cell system with hydrogen membrane separation

In this work we report a simulative energy efficiency analysis performed on innovative fuel processor – PEM fuel cell systems in which hydrogen is produced via methane autothermal reforming, separated with a membrane unit coupled with a water gas shift reactor and then converted into electric energy by means of the PEM fuel cell. Two basic configurations are investigated: one with the membrane unit placed downstream the water gas shift reactor and the other with the membrane unit embedded into the water gas shift reactor. The results are discussed and compared with the case of a fuel processor constituted by an autothermal reforming reactor followed by two water gas shift reactors and a preferential CO-oxidation reactor. Pressure, steam to methane and oxygen to methane inlet ratios are explored as operation variables. The effect of addition of steam as sweep gas into the permeate side of the membrane is also presented and discussed.