Development of advanced methods of determining the chemical stability of hydrocarbon fuels

•Accurate determination of parameters is important for rocket fuels.•Parameter values affect shelf life.•existing methods have a large error. Experimental studies have shown that it is impossible to obtain reliable values of chemical stability indices of hydrocarbon fuels using the existing methods of fuel quality control. Techniques for the determination of such chemical stability indices of hydrocarbon fuels as the content of existent gums and oxidation degree, to the improvement of which this article is devoted, are identical both in the Russian Federation and in countries of the European Union. In order to improve the method for determining the content of existent gums in hydrocarbon fuels and create a new method for determining the oxidation degree, experimental studies were carried out, which allowed establishing correlations between the oxygen consumed for oxidation and final products of oxidation. Based on the conducted studies, an addition to the existing technique for determining the content of existent gums in hydrocarbon fuels is given, which allows for the elimination of the new formation of oxidation products in the course of measurements. The carried out experimental studies allowed for the development of a new technique for determining the oxidation degree of hydrocarbon fuels. It was experimentally established that the amount of the oxygen consumed for hydrocarbon fuel oxidation correlated well with the oxidation degree index, which made it possible to take the amount of the oxygen consumed for oxidation and the concentration of solubilized water as the basis for the new method of determining the fuel oxidation degree. A scheme of the installation for determining the concentration of solubilized water in hydrocarbon fuel and a technique of measurements are given. After the calculation of the concentration of solubilized water, the amount of the reacted oxygen referred to the hydrocarbon volume and the fuel oxidation degree are determined as per the experimental nomographic chart.