The Behavior of Water in Jet Fuels and the Clogging of Micronic Filters at Low Temperatures

Abstract : A study of the behavior of water in fuels, and its effect on the clogging of micronic type filters, especially at low temperatures has been made. A method for the determination of water in fuels using the Karl Fischer reagent has been developed and used in the determination of the solubility of water in several fuels and pure hydrocarbons from 32 deg F to 120 deg F. The effect of aromatic content, rates of saturation and disappearance of suspended water from fuels have been investigated. A small scale apparatus was devised for the study of the clogging of micronic filters at low temperatures. The variables - temperature, water content of the fuel, fuel pressure, porosity and type of paper were studied for their effects on filter clogging. Mechanisms of clogging as a function of temperature are proposed. A number of representative substances were tested as potential freezing point depressants for the prevention of clogging. In general, it was found that the more hydrophylic compounds are the more effective antifreezes. However, these compounds are the ones more readily leached from the fuel by contact with water. Methyl alcohol was found to have the best antifreeze action, but it is lost very readily from fuel solutions to water. In selecting a suitable antifreeze, due consideration must be given to the methods of handling the fuel and to the methods which may be used for the introduction of the additive.