To improve the efficiency, lifetime and costs of fuel cell systems new process concepts are discussed continuously, also membrane applications especially in the field of on-board hydrogen generation. By implementing a metal membrane in the reaction chamber of a reformer, the size and complexity of the fuel cell system can be reduced significantly. By using a membrane the hydrogen is removed during the reaction and the fuel conversion rate increases in comparison to a conventional steam reformer.
Within a public funded project the catalytic steam reforming of GTL fuel (gas to liquid) into a hydrogen-rich reformate was successfully performed. This fuel was used due to the fact that BTL fuel (biomass to liquid) was not commercially available until the end of the project. The named fuels are only different by the resource. However, in terms of the composition they are identical.
The catalytic steam reforming of GtL in the developed reformer-burner-units was carried out with four different systems, one of which has been selected to be coupled to the membrane unit. Palladium membranes with two different membrane structures and two different ceramic intermediate layers (yttrium-stabilized ZrO2, YSZ and titanium dioxide, TiO2) were prepared. The intermediate layers were optimized in terms of high nitrogen permeances and small maximum pore diameter. Ten palladium membranes were manufactured by electroless plating process and tested. H2/N2-perm selectivities could be increased from values between 20 – 40 to values between 100 – 400. Simulations of membrane reformer with PEMFC systems have been executed and show a high potential for the electrical efficiency. A new concept for a membrane reformer has been designed, tested and developed iteratively. Thereby a flue gas powered educt conditioning, a retentate recirculation system and a sweep gas system were developed and tested. Finally, two refomer-burner-units were coupled with two membrane units to assemble two membrane reformer systems, which were successfully operated with GTL fuel. The generated hydrogen rich gas can be used for the operation of a HT-PEM fuel cell.
Further information
- Decentralized production of hydrogen
- Projects of ZBT
- Published project reports
- division fuel processing
