Novel thiotolerant catalysts for the on-board partial dehydrogenation of jet fuels

The possibility of producing on-board H2 by dehydrogenation of petrol derivates is interesting for transport applications. Traditional Pt-Sn systems, however, cannot be used without purifying the fuel from its sulphur content, and the dehydrogenation reaction consumes energy owing to its endothermic nature. To limit the energy demand for the entire process, it is necessary to eliminate the need for any reactant purification step, thus feeding the real fuel without desulphurization. In this respect, Ni- and Co-based catalysts capable of working under hydrodesulphurization conditions answered such demand, allowing them to carry out the reaction in the presence of sulphurated organic substrates. Tests conducted on nickel and cobalt phosphides, as prepared from the corresponding dihydrogenphosphite by temperature programmed reduction and supported on silica Cab-osil, indicated these materials as very active catalysts capable of producing 1500 N l per h per kgCAT of H2 after 24 h of reaction in the presence of 50 ppm of sulfur. These catalysts remained active and stable even when 250-500 ppm of sulphur was introduced in the feed.