Methane steam reforming operation and thermal stability of new porous metal supported tubular palladium composite membranes

Ideal H2/N2-permselectivities between 700 and almost 10,000 were measured at 600 °C and hydrogen transport kinetic parameters were determined for both membrane types. PVD/ELP-membranes reached a 15% higher H2-permeability than PVD/EP-membranes. Moreover, stability tests were carried out indicating that the membranes are resistant to temperature and feed gas changes, to thermal cycling in N2-atmosphere between room temperature and 650 °C, and to short-term high-temperature methane steam reforming (MSR) at 700 °C. Long-term operation for several hundred hours at realistic operating conditions proved that MSR can be performed without degradation of the membranes. Without optimizing membrane area versus feed load, a maximum methane conversion of 60% was achieved at a H2-recovery of 70% at 650 °C, 16 bar(a) and a S/C of 3 without the use of sweep gas.