(11b) Mild Solvolysis Liquefaction of Low-Rank Coal into a Feedstock of Value-Added Carbon Materials
AIChE Annual Meeting
Sunday, November 7, 2021 - 3:55pm to 4:20pm
In the research presented here, low-rank coals from various American coal-producing areas were liquefied by solvolysis at mild temperature conditions. Macromolecules in coal were dissolved, fragmented, rearranged, partially hydrogenated, and converted into DCL tar with high yields (over 50%), while most of the aromatic or naphthenic structures in raw coals were preserved. The DCL tar contained more heavy fractions and hydrogen transferability attributes than pyrolysis tar and coking tar. Results of subsequent thermal treatment indicated that this kind of DCL tar can be effectively converted into mesophase pitch with excellent anisotropic characteristics. The obtained mesophase pitch is of promising potential to produce high-performance carbon materials such as carbon fiber, needle coke, carbon foam, and supercapacitors. Products and byproducts were characterized analytically (TGA, FTIR, NMR, BET, SEM, etc.), and a mass balance was evaluated for the process. The influence of operating parameters (liquefaction temperature, solvent types, initial gas atmosphere, and solvent/coal mass ratio) on the yield, composition, and carbonization performance of DCL tar was studied and will be discussed. The possibility of replacing hydrogen donor solvents and H2 gas sources with cheap and renewable feedstocks was also investigated. Our research indicates that mild solvolysis liquefaction of low-rank coals can be used to generate value-added product precursors in coal-producing areas of the United States.