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Hydrogen on demand technologies
A hydrogen on demand vehicle uses some kind of chemical reaction to produce hydrogen from water. The hydrogen is then burned in an internal combustion engine or used in a fuel cell to generate electricity which powers the vehicle. While these may seem at first sight to be 'water-fuelled cars', they actually take their energy from the chemical that reacts with water, and vehicles of this type are not precluded by the laws of nature. Aluminium, magnesium, and sodium borohydride are chemicals that react with water to generate hydrogen, and all have been used in hydrogen on demand prototypes. Eventually, the chemical runs out and has to be replenished.[36][37][38] In all cases the energy required to produce such compounds exceeds the energy obtained from their reaction with water.[39]
One example of a hydrogen on demand device was created by scientists from the University of Minnesota and the Weizmann Institute of Science. Their scheme uses Boron to generate hydrogen from water. An article in New Scientist in July 2006 described the power source under the headline "A fuel tank full of water,"[39] and they quote Abu-Hamed as saying:
The aim is to produce the hydrogen on-board at a rate matching the demand of the car engine. We want to use the boron to save transporting and storing the hydrogen.
A vehicle powered by the device would take on water and boron instead of petrol, and generate boron trioxide. The chemical reactions describing the energy generation are:
4B + 6H2O → 2B2O3 + 6H2 [Hydrogen Generation Step]
6H2 + 3O2 → 6H2O [Combustion step]
The balanced chemical equation representing the overall process (hydrogen generation and combustion) is:
4B + 3O2 → 2 B2O3
As shown above, boron trioxide is the only net byproduct, and it could be removed from the car and turned back into boron and reused. Electricity input is required to complete this process which Al-Hamed suggests could come from solar panels.
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23 ส.ค. 51 00:48:46
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