Iakovlieva A. Physical-chemical properties of jet fuels modified with components of plant origin

The thesis is devoted to the question of jet fuels modification with components obtained from domestic feedstock of plant origin and study of new aviation biofuels properties. The modern state of jet fuels production was studied. The perspective technologies as well as variety of feedstock for alternative jet fuels production were analyzed. The rational method of biocomponents production from products of rape oil processing is proposed. It includes vacuum distillation of fatty acids methyl and ethyl esters under the pressure 0.4-0.7 kPa and temperature 135-226 °C. Biocomponents with improved properties were firstly used for modifying the composition of conventional jet fuels. It was found that the interaction mechanism within the system "hydrocarbon fuel - esters" is stipulated by Van-der-Waals dispersive and induction forces of intermolecular interaction. Basing on these results the influence of biocomponents on physical-chemical properties of jet fuels was determined. The complex experimental studies of physical-chemical, exploitation and ecological properties of jet fuels modified with bicomponents were done. The results showed that increasing of density, viscosity and freezing point of modified jet fules is explained by the rise of dispersive interaction energy between molecules of hydrocarbon fuels and fatty acids esters. It was proved that fatty acids esters may be used for modifying the composition of conventional jet fuels in quantity up to 30 % (vol.) without a need for making changes in construction of aircraft jet engines. It was shown that modification of jet fuels with 30 % of biocomponents results in improvement of their exploitation properties. The antiwear properties are increased on 63.73 and 64.7 % and fire point is increased on 9.19 and 6.93 % in the result of jet fuels modification with fatty acids methyl and ethyl esters respectively. It was proved that modification of jet fuels with 30 % of biocomponents results in improvement of their ecological properties. During the combustion of modified jet fuels the SO2 emissions are decreased on 19.8 and 22.08 % and СO2 emissions are decreased on 3.002 and 2.87 % in the result of modification with fatty acids methyl and ethyl esters respectively. The mathematical equations, which allow optimizing processes of compounding hydrocarbon jet fuels with components of plant origin, were derived. The proposed empirical functions may be used for obtaining modified jet fuels with desired properties. The criteria for selecting the rational composition of jet fuel modified with components of plant origin were stipulated. The receipts of new modified jet fuels, which contain up to 30% of biocomponents and posess improved exploitation and ecological characteristics, were proposed.