A gas turbine, says Daedalus, is a collection of combustion chambers directing its flame onto a set of turbine blades. The shaft horsepower drives a compressor to feed the combustion process, and the exit gas forms a jet exhaust (in the jet engine). The turbine blades, directly in the path of the flame, have a severe duty, and can be internally cooled. A hollow blade with a divider along the middle can receive water through a hollow central shaft. In the centrifugal field the water will cling to the outside of the shaft bore, and even a small difference in density (caused, for example, by boiling) will circulate the water vigorously through the blade. Daedalus calculates that a fast-spinning turbine could drive the water in its blades supercritical at the blade tips.

Oxygenated, supercritical water is a powerful and spontaneous oxidizing agent. A turbine fed not with cooling water, but with an oxygenated fuel slurry, would therefore generate heat in its turbine blades by burning the fuel circulating in them. So DREADCO engineers are now building turbines whose combustion is distributed between the combustion chambers and the first few rows of blades. Indeed, Daedalus reasons that an internally heated blade could generate torque on its own account, making possible an entirely new sort of turbine.

The major application of turbines with water-loaded blades will be chemical, however. Many processes generate a weak slurry of some nasty organic chemical, and it is appealing to burn this in a turbine to a solution of CO2 in water, and get useful power in exchange. The pharmaceutical industry, with innumerable waste streams on the way to a few useful products, would be an obvious customer. And the sewage business is dedicated to turning its customers' waste into a weak water slurry, and getting rid of this somehow. Burning it in turbines could generate vast amounts of electricity. Even the waste heat, now represented by the hot fizzy water rejected by the turbines, should be easy to discharge. Expensive cooling towers might not be needed.

Even better, many reactions of 'green chemistry' seek to replace messy industrial processes by neat supercritical ones from which the product can be elegantly recovered by simple processing. What a pity that supercritical dry cleaning, a splendid way of tidying up tatty or dirty assemblies, cannot be reduced to turbine processing.