Grynyshyn K. Production of motor fuel components based on the products of thermoplastic waste processing

This dissertation work is devoted to an actual technological and ecological problem - the study of the process of low-temperature pyrolysis of waste thermoplastics for the purpose of obtaining components of motor fuels. The processing of thermoplastic polymer waste by low-temperature pyrolysis makes it possible to obtain the maximum amount of liquid product - pyrocondensate - which can later be used for the production of commercial motor fuels. In addition, pyrolysis gases and a small amount of solid product - pyrocarbon, which are byproducts of the pyrolysis process, are obtained. The purpose of the dissertation work is to develop the basics of the technology for obtaining components of motor fuels from the pyrocondensate of pyrolysis of thermoplastic waste. In the first chapter of the dissertation, the problem of the accumulation of polymer waste in Ukraine and the world is considered, the classification of the methods of utilization of polymer waste is given. The main methods of polymer waste disposal are described: landfill, incineration, recycling, solvolysis (hydrolysis, glycolysis, methanolysis), conversion (thermal pyrolysis, catalytic pyrolysis, gasification). The advantages and disadvantages of these methods of polymer waste disposal are indicated. Methods of rubber waste processing are described. It was concluded that the method of low-temperature thermal pyrolysis of polymer waste deserves special attention, as it allows obtaining the maximum amount of liquid hydrocarbons and is technically simple and relatively inexpensive. Also, in this section, the main tasks that must be solved in the dissertation work are formulated. The second chapter of the dissertation provides a general description of the thermoplastic wastes selected for further research: high-density polyethylene, polypropylene, and polystyrene. The waste of these polymers is the most massive polymer waste, and their secondary processing by traditional methods is complicated. This section also provides a description of the methods of conducting analyzes and experiments that were used during the dissertation work. The third chapter of the dissertation presents the results of the low-temperature pyrolysis of polyethylene, polypropylene, and polystyrene waste. For this purpose, the conditions were chosen based on the results of thermogravimetric analysis of waste (for the pyrolysis of polyethylene waste – 410 C; polypropylene – 380 C; polystyrene – 400 C). For comparison, low-temperature pyrolysis of rubber waste was carried out. It was established that the yield of the target product (pyrocondensate) of pyrolysis of thermoplastic waste is significantly higher than that of pyrocondensate of pyrolysis of rubber waste. The principle possibility of using light fractions isolated from the pyrocondensate of pyrolysis of thermoplastic waste as components of commercial gasoline and diesel fuel, subject to additional processing at oil refineries, has been established. In the fourth chapter of the dissertation, the influence of the mode of pyrolysis of polyethylene and polypropylene waste on the yield and properties of pyrocondensate is studied. It was established that the higher the pyrolysis temperature, the lower the yield of the liquid product – pyrocondensate. At higher temperatures, pyrocondensate of a lighter fractional composition is formed. The composition and properties of narrow fractions and the residue isolated from the pyrocondensate of pyrolysis of polyethylene and polypropylene waste, carried out in different modes, were studied. It was established that all fractions and the residue contain unsaturated hydrocarbons, which is confirmed by the high iodine value. The fifth chapter of the dissertation describes the technological aspects of obtaining motor fuel components by low-temperature pyrolysis of thermoplastic waste. Technological recommendations for obtaining motor fuel components from the pyrocondensate of the pyrolysis of these wastes have been developed. Directions for the use of by-products of the pyrolysis process of thermoplastic waste are proposed. It is proposed to use pyrocarbon as an adsorbent for the collection and localization of oil and oil spills on solid and water surfaces. The basics of thermoplastic waste technology were developed – a basic technological scheme of the pyrolysis facility was proposed, a technological map was drawn up, and the material balance of the pyrolysis process was calculated. The production cost of pyrocondensate pyrolysis of thermoplastic waste was calculated and the feasibility and high efficiency of processing thermoplastic waste by the low-temperature pyrolysis method to obtain motor fuel components was confirmed. The results of the conducted research were implemented in the educational process for the training of students in theoretical classes on the discipline «Modern trends in the secondary processing of polymer waste», which confirmed by the act of implementation.