LONDON, Oct 19 - The green car of the future could run on a tankful of iron filings, it was claimed today.
A US scientist believes it could be possible to replace petrol and diesel fuel with finely powdered iron.
A car running on burning metal would produce almost no pollution and travel three times further than an equivalent petrol-powered vehicle, says Dr Dave Beach.
Dr Beach even has visions of a new Iron Age'' with metal driving not only cars, but aircraft, military vehicles, domestic heating units and power station turbines. Given a high enough temperature, powdered iron and other metals ignite releasing far more energy than petrol. Rockets already use metal power. A dash of aluminium is sprinkled into the space shuttle's solid rockets to give them an extra boost. But to kick off combustion in most metals requires temperatures of at least 2,000 degrees Celsius, which would melt the average engine. Dr Beach, from Oak Ridge National Laboratory in Tennessee, suspected the answer was to create very fine powders with grains just nanometres - millionths of a millimetre - across. Tests proved that iron particles measuring about 50 nanometres ignited much more easily than larger grains. Heating them to about 250C, or even a spark, could make them burn. Unlike larger particles, they did not vaporise or melt to produce ash which would clog up an engine. Instead they simply oxidised, leaving a heap of oxide nanoparticles. A car run on such a metal fuel would produce no carbon dioxide, no dust, no soot and no harmful nitrogen oxides, new Scientist magazine reported. The scientists also discovered that iron oxide waste could be converted back into useful fuel by heating it in a flow of hydrogen. The particles were reduced to iron, while the hydrogen combined with oxygen to produce water. Adjusting the size, shape and density of nanoparticle clusters made it possible to control the burn rate. Metal powder could be injected into engine cylinders from a storage tank, possibly using a jet of air which would also supply the oxygen needed for combustion, say the scientists. An electromagnet would be used to collect the spent fuel in a container. A vehicle running on metal fuel should please both drivers and environmental campaigners,’’ said New Scientist.
Beach calculates that a fuel tank holding 33 litres of his iron fuel will power a car engine for the same distance as a 50 litre tank of conventional petrol or diesel.'' Weight is one possible drawback, however. Although iron is a compact fuel it is also extremely heavy. A 33-litre fuel tank filled with iron nanoparticles would weigh around 100 kilograms - more than twice as much as the same volume of petrol. The idea raises one intriguing possibility - making a fortune from scrap metal. In the past, energy magnates have earned billions from coal, oil and gas fields,’’ said New Scientist.
``In the future, they could grow rich from scrapyards full of yesterday’s cars, by transforming them into fuel for the vehicles of tomorrow.’’