Submission + - US Navy Tries to Turn Seawater into Jet Fuel
Hugh Pickens writes: "The New Scientists reports that faced with global warming and potential oil shortages, the US Navy is experimenting with making jet fuel from seawater by processing seawater into unsaturated short-chain hydrocarbons that with further refining could be made into kerosene-based jet fuel. 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, 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. The navy team have been experimenting to find out how to steer the CO2-producing process away from producing unwanted methane by finding a different catalyst than the usual cobalt-based catalyst. "The idea of using CO2 as a carbon source is appealing," says Philip Jessop, a chemist at Queen's University adding that to make a jet fuel that is properly "green", the energy-intensive electrolysis that produces the hydrogen will need to use a carbon-neutral energy source; and the complex multi-step process will always consume significantly more energy than the fuel it produces could yield. "It's a lot more complicated than it at first looks.""
