produced by natural gas under similar conditions • An alternative method suggested for H 2 storage/transportation is to convert it into solid metal hydrides, MH 2 .
Alternative Fuels • Hydrogen gas is most efficient and clean fuel • It produces the most energy per gram, • Transportation and storage are difficult • It requires a much large fuel tank than gasoline; • May be compressed into liquid form, but poses explosion hazard • An alternative way is to convert it into a solid metal hydride (MH 2 ) – one that is able to release H 2 when heated. • Most likely the hydrogen will be used to power fuel cells that will be installed in automobiles
Alternative Fuels • Oil shale – Shale rocks contain complex HC called kerogen – Huge deposits in western states, especially Colorado; – Kerogen is not fluid like petroleum - cannot be pumped; – Rocks containing fuel must be heated to >250 o C to decompose the kerogen into smaller HC molecules; – Process produces large quantities of waste rocks – a negative environmental impact.
Alternative Fuels • Ethanol: – Produced by fermentation of sugar (from sugar cane or corn) – Pure ethanol produces about 27 kJ/g of energy – Use as fuel supplement – Added to gasoline as gasohol (which contains ca. 10% ethanol) – Pure ethanol not suitable for motor fuel in USA, especially in winter, because it does not vaporize easily in cold climate. – Pure ethanol is widely used as motor fuel in Brazil where the climate is warmer.
Alternative Fuels • Methanol: – Methanol produces about 20 kJ/g of energy when completely combusted – It has been used in race cars as a mixture of 85% methanol and 15% gasoline. – California is evaluating methanol as motor fuel – Arizona and Colorado are considering similar step.
You've reached the end of your free preview.
Want to read all 44 pages?