Vanadium Poisoning from Gas Turbines

Vanadium pentoxide poisoning has been described in men working in plants processing vanadium ore by Symanski (1939) and Sj?berg (1950), and twice (Wyers, 1946 ; Williams, 1952) in men exposed to the soot of fuel oil burned in boilers. It does not, however, appear to have been described before in men who work on gas turbines. Since these may become much more common in the future as sources of power using residual fuel oil for generating stations, ships, and locomotives, and also possibly for cars and omnibuses, it is worth bringing together the medical, engineering, and preventive aspects of the problem as far as they are known at present. Vanadium is found in all fuel oil and remains in the residual heavy oil after the more volatile fractions, such as petrol, paraffin, and diesel oil, have been distilled. It is, therefore, only a consti tuent of the exhausts of gas turbines using heavy residual fuels. Vanadium, which is present in the natural oil in complex compounds, appears as the pentoxide after combustion, and this forms an acid solution in water. To improve the thermal efficiency of some types of gas turbine, the exhaust gas is made to heat the air from the compressor, and this is done in a heat exchanger which may take the form of a large metal box filled with tubes, outside which the hot exhaust gas flows. The intake air is inside the tubes which are arranged in a particular configuration. The products of combustion are deposited on the outside of these tubes. But in some types of heat exchanger the relative situations of exhaust gas and intake air are reversed, and in these the products of combustion will be deposited on the inside of the tubes. The 12