Direct liquefaction behaviors of Bulianta coal and its macerals

Abstract

Liquefaction behaviors of Bulianta raw coal (RBC) and its macerals were investigated in a tubing-bomb micro-reactor. TG/DTG analyses show more weight loss of vitrinite-rich sample (VBC) than inertinite-rich sample (IBC) and RBC despite similar peak temperatures with maximum weight loss rate. The total yield and oil yield are in the order VBC>RBC>IBC at same liquefaction conditions, and VBC releases more alkane gases (C1–C3) than IBC. Moreover, total yield and oil yield of VBC under N2 without catalyst are even higher than those of RBC and IBC in H2, which are mainly attributed to higher H/C ratio, volatile and lower average number of aromatic ring of VBC than IBC. The effects of catalyst and solvent on liquefaction are related with atmosphere and coal sample properties. Fe-based catalyst promotes H2 activation and activated hydrogen formation, and is beneficial to the hydrogenation of free radical fragments in H2, but it only increases gas yield under N2. The solvents affect total yield and product distribution of macerals more under N2 than that in H2. Addition of 2vol.% H2S to H2 obviously promotes conversion of preasphaltene and asphaltene into oil when tetralin as solvent with Fe-based catalyst, further improving oil yield.