Title : Production of hydrogen by catalytic partial dehydrogenation of a commercial fuel for HT PEM fuel cell applications
Integration of fuel cell systems in electrified transportation calls for the development of efficient processes for high purity hydrogen supply. Partial dehydrogenation of liquid fuels has recently emerged as a transition technology for hydrogen delivery purposes. The reaction is carried out on a complex mixture of hydrocarbons and the principle is to extract from fossil fuels a small fraction of the available hydrogen, which is used by the fuel cell, while the dehydrogenated hydrocarbon mixture retains suitable properties for its use as a fuel in a combustion engine. The challenges lie in improvement of hydrogen productivity without detriment to the purity of the hydrogen generated, which requires development, optimisation and scale-up of advanced catalysts, as well as process optimisation. The choice of the catalyst is crucial for the partial dehydrogenation process; it must produce H2 without compromising the original fuel properties. An ideal catalyst must be sulfur tolerant, generate sufficient hydrogen of high purity, be selective to dehydrogenation and avoid cracking reactions responsible for coke deposition and catalyst deactivation
The partial dehydrogenation (PdH) of a commercial gasoline (SP95E10) was carried out in a continuous flow reactor at 370ºC and 8 bar. The catalyst used was 1 wt% Pt-1 wt%Sn-0,5 wt% In supported on alumina prepared by a sol-gel technique, and the active phase was added by incipient wetness impregnation. This catalytic material showed a very good activity and high selectivity, leading to a gas production of 2300 NL/h•kgcat with 99% hydrogen purity and very low amounts of CO and methane.
The hydrogen produced was fed to a HT-PEM fuel cell operated at 160 °C. At a current density of 200 mA/cm2 the performance of the fuel cell with the hydrogen produced by partial dehydrogenation was close to that obtained with pure hydrogen. The complete recovery of performance to that with pure hydrogen indicates the absence of any irreversible catalyst poisoning effect when using the PdH hydrogen, and no voltage loss over a 13 h period of measurement.