Authors: I.Y. Petrov, A.V. Osipov, A.R. Bogomolov

Title of the article: Catalytic liquefaction of coals - a promising way to produce motor fuels and valuable chemical compounds. Part 4. Factors Influencing the Processes of Coal Liquefaction: Process Conditions and Coal Pretreatments

Year: 2021, Issue: 5, Pages: 64-81

Branch of knowledge: 05.17.07 Chemical technology of fuel and high-energy substances

Index UDK: (66.092.094.25.097+66.061):552.57

DOI: 10.26730/1999-4125-2021-5-64-81

Abstract: The article discusses a role of the main technological parameters (temperature, pressure, duration of the experiment) in the direct coal liquefaction processes. With an increase in the reaction temperature, the degree of bond destructions in coal structure increases, which leads to "depolymerization" of coal macrostructure, an increase in the yield of liquefaction products and a decrease in their viscosity due to a decrease in the average molecular size of the detached coal components. An increase in the reaction time, like an increase in temperature, usually facilitates a rise in coal conversion, but with a long duration of the liquefaction process (especially at high temperatures), the decreases of coal conversion and yields of liquid products are observed, as well as deterioration in the resulting "coal liquids" quality (due to the increased contribution of regressive reactions) may occur. The dependence of coal liquefaction characteristics on hydrogen pressure in the reactive system is more complex and is largely determined by petrographic and chemical composition of coal, as well as its origin. Effects of various methods of coals pretreatment (drying or heat treatment in the presence of solvents, oxidation, alkylation, treatment with various reagents) on the characteristics of coal liquefaction processes are considered.

Key words: coal liquefaction processes temperature pressure preliminary coal treatment conversion liquefaction products

Receiving date: 03.09.2021

Approval date: 25.10.2021

Publication date: 24.12.2021

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