Change her up, please

In twenty years time we will drive on ammonia borane instead of gasoline, Andrew Sutton and colleagues surmised last week in Science.

 Filling up a fuel tank yourself will become a romantic relic of the past associated with big, roaring gasoline consuming automobiles. In future drivers will exchange their empty fuel tanks at a fuel station for new ones. And the tanks won’t be filled with gasoline, but rather with ammonia borane, a lightweight material that contains lots of hydrogen (19.6 weight percentage).That is the vision presented by scientists at the Los Alamos laboratory in New Mexico (US). They believe that ammonia borane is the material that will help us get past our oil addiction.

Hydrogen can be stored efficiently in ammonia borane and when put in a solution that has some nickel-based catalyst added to it, the hydrogen can also easily be delivered from that material to energy-producing fuel cells. One of the remaining challenges however is to find a way to regenerate ammonia borane from the spent, dehydrogenated fuel. But in last week’s edition of the Science, US chemists describe a way to do just that. A 24-hour treatment with a rocket fuel, called hydrazine, in liquid ammonia at 40°C in a sealed pressure vessel puts all the hydrogen back in place.

The biggest bottleneck the researchers face now, they say, is the high price of hydrazine, which currently costs around 4.00 US dollars per kilo. But that price can drop fast, the researchers add, if the production process is scaled up, which of course would happen if the whole world is driving on ammonia borane instead of gasoline.

Professor Fokko Mulder, of the Fundamental Aspects of Materials and Energy section (Applied Sciences), who conducts research on magnesium hydrides as a hydrogen storage material, sees some other hurdles as well. Although he says that this research ‘certainly is an important step’, he’s far from convinced that we’ll all be driving on ammonia borane in the near future.“The ammonia borane needs to be in a solution that will lower the effective hydrogen weight percentage,” he says.

Prof. Mulder also worries about toxic compounds: “How will the researchers prevent the chemical borane from being formed in the fuel tank during the release of hydrogen? They do not write about that. Borane is very bad for the fuel cell. And worse, if you hit a tree and your fuel tank rips apart, the toxic substance can be released in the environment.” Professor Bernard Dam, of the Materials for Energy Conversion and Storage section (Applied Sciences), has similar reservations, yet these concern the ammonia which will also be produced. “They’ll have to add filters or invent some other complicated technique to prevent the ammonia from reaching the fuel cell and intoxicating it,” he opines.

Prof. Mulder also wonders how the Americans plan to deal with the catalyst that will still be present in the ‘empty’ fuel tank: “You have to remove that before you start the process to regenerate ammonia borane, since the catalyst counteracts this process. They may have worked out a way to do this in the laboratory, but if you do it on a much larger scale it becomes more complicated.”

Het is de LSVb gelukt. Studenten met een weekendkaart kunnen voortaan weer gratis met de trein reizen op de middag voorafgaand aan een feestdag, zelfs als die feestdag op een doordeweekse dag valt.

De regeling is net op tijd in ere hersteld, want er komt een reeks doordeweekse feestdagen aan. Koninginnedag natuurlijk, maar ook 5 mei. De week daarop is het donderdag Hemelvaartsdag. Ook met een weekendabonnement kunnen studenten de dagen ervoor gratis reizen na twaalf uur ‘s middags.

Zo stond het ook in de folder ‘Studentenreisproduct’ van de Informatie Beheer Groep (tegenwoordig DUO). Maar een jaar geleden ontvingen studenten een brief: de ‘middagregeling’ zou vanaf 2010 vervallen. Ten onrechte, vond de LSVb. De bond klaagde erover bij het ministerie en de IB-Groep en kreeg gelijk.

Na Hemelvaartsdag is het voorlopig afgelopen: Tweede Pinksterdag is een maandag en Kerstmis valt in het weekend.