Going nuts for a hydrogen-fuelled future

IF YOU want to go green, get out your nutcrackers. Scientists in Britain
say hazelnuts could provide the hydrogen to power the fuel-cell driven
cars of tomorrow. Fuel cells use hydrogen to generate an electric
current, and researchers are trying to make them efficient enough to
power electric and hybrid cars (New Scientist, 25 November, p 34). But
no one has decided how that hydrogen will be best produced.

But now Murat Dogru of the University of Newcastle says hazelnuts could
be an answer. He says Turkey, the world's largest producer, incinerates
around 250,000 tonnes of shells a year. To see if any useful gases could
be extracted from this waste, Dogru and his colleagues fed hazelnut
shells into a container called a gasifier. The chamber contains solid fuel
lighters and is fitted with an air pump. Once you ignite the fuel, the air
pump controls the oxygen supply--and so the heat produced in the
gasifier. Controlling the oxygen determines which gases are given off.
Dogru says the system is cheap to run. "You don't supply a lot of extra
energy. You just ignite it for a few minutes, then the nutshells fuel it," he
says.

Hydrogen makes up 15 per cent of the combustion gases. The remaining
gas is a mixture of carbon monoxide, methane, nitrogen and carbon
dioxide. But Tony Bridgwater of Aston University in Birmingham says
these other gases needn't be a problem. Both methane and carbon
monoxide can be converted to carbon dioxide and hydrogen by reacting
them with water, he says. "Then you can use standard procedures for
stripping out the carbon dioxide," he adds.

Dogru says a year's supply of Turkey's nutshells would produce 6000
tonnes of hydrogen--enough to allow 1000 of today's prototype
hydrogen-fuelled BMWs to travel 32,500 kilometres each.

International Journal of Hydrogen Energy (vol 26, p 29)

Ian Sample

From New Scientist magazine, 09 December 2000.

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