Ph.D. Thesis in Engineering Sciences Majoring in 05.17.07 – Fuels and Lubricants Chemical Engineering. – National Aviation University, Kyiv, 2020.
The thesis is devoted to the development of scientific principles of chemmotology,
in particular, to the improvement of saving technologies and quality assurance of aviation fuels, as well as technological aspects of maintaining chemmotological reliability
of aviation equipment aimed at ensuring biological stability of aviation fuels.
An axiomatic-phenomenological description of the mechanism of biodegradation
of aviation fuels is proposed. The highest level of biodegradation was found on Hormoconis resinae in alkane hydrocarbons with a longer carbon chain.
Microorganisms have the selective ability related to various hydrocarbons, and this ability is determined not only by the difference in the structure of substance, and even the number of carbon atoms that are the part of their structure.
Developed understanding of microbial damage jet fuel as a process consisting of three interconnected stages in series: interaction (adhesion) of microorganisms with fuels - growth in the environment of fuel hydrocarbons - change of fuel properties.
According to microbial stability, the studied fuels are ranked (in ascending order) in the following order: automobile gasoline - jet fuel - diesel fuel - aviation gasoline.
An irreversible change in the quality indicators of aviation fuels (acidity, corrosion activity, the content of actual resins, thermo-oxidative stability, heat of combustion, temperature of the beginning of crystallization, kinematic viscosity) due to microbial damage. А biocorrosion of the fuel system and aircraft structures is part of the problem fuel with microbiological contamination.
Among the destructive microorganisms, the most common are fungi. They are systematized into three groups: 1 – active destructors (for example, Hormoconis resinae); 2 – potential destructors (for example, Aspergillus ustus and Geotrichum candidum);
3 – partially adapted to the environment and random micromycetes.
Determining factors for the development of microbiological damage in aviation fuels are temperature (~ 28 oC) and moisture. It is shown that the content of microorganisms up to 104 cells/m3 is considered safe and does not pose a risk to flight safety.
It was found that the presence of biocomponents (ethyl esters of fatty acids) accelerates the development of the microbial phase in aviation fuels.
The colorimetric method of microbiological contamination developed on the basis of Rueman's reaction is checked and its efficiency and reliability in comparison with the known method of testing MicrobMonitor2 is checked and confirmed. The level of validation of the method for intra-laboratory reproducibility is 98 %.
Developed understanding of the effectiveness of biocide applications. The most effective were biocides of the brands formacid-13, Kathon FP 1,5, Grotan OX, Biobor, Akticide OX, Akticide MV14 with the maximum effective concentration of 0,1 %.
Problem-thematic content of the work is mainly devoted to the creation of practical recommendations for ensuring the biological stability of aviation fuels. An important component of this recommendations is the frequent checks of drainage systems, as well as regular testing and monitoring of microbiological contamination of the fuel and fuel system.
Key words: fuel, microbial damage, aviation, chemmotology, reliability, durability, stability, properties, biodegradation, oxidation, quality, colorimetric indicator method, biocides, monitoring, recommendations, model.
