Navy chemists have processed seawater into unsaturated short-chain hydrocarbons that with further refining could be made into kerosene-based jet fuel. But they will have to find a clean energy source to power the reactions if the end product is to be carbon neutral.
The process involves extracting carbon dioxide dissolved in the water and combining it with hydrogen – obtained by splitting water molecules using electricity – to make a hydrocarbon fuel.
It uses a variant of a chemical reaction called the Fischer-Tropsch process, which is used commercially to produce a gasoline-like hydrocarbon fuel from syngas, a mixture of carbon monoxide and hydrogen often derived from coal.
Robert Dorner, a Naval Research Laboratory chemist in Washington DC and first author of a new paper on the technique, says that CO2 is rarely used in the Fischer-Tropsch process because of its chemical stability.
But CO2‘s abundance, combined with concerns about global warming, make it an attractive potential feedstock, Dorner says. Although the gas forms only a small proportion of air – around 0.04 per cent – ocean water contains about 140 times that concentration, he says.
and,
George Olah advocates turning CO2 into methanol and further spinning off the whole methanol economy. Another way to mitigate the petroleum crisis.