Study on the stability of hydro-liquefaction residue of Shenfu sub-bituminous coal

• DCLR and its components have different pyrolysis behaviors.
• THFI formed by the condensation of oxygen containing functional groups.
• THF soluble is more prone to form the THFI at lower temperature.

The stability of direct coal liquefaction residue (DCLR) has significant effects on the DCL technology and the utilization of DCLR. In this paper, the pyrolysis behaviors of the DCLR from 6 t/d Shenhua BDU technology and its components including tetrahydrofuran soluble (THFS) and insoluble (THFI) were investigated by thermogravimetric analysis (TGA). Then, its thermal stability and THFS hydrogenation activity were studied by thermal treatment and hydrogenation treatment, respectively. Results show that DCLR and its components have different pyrolysis behaviors. Inorganic components existed in DCLR and THFI show a catalytic effect on the pyrolysis of organic matrix, but THFS inhibits the decomposition of carbonates in DCLR. The weight loss of THFI mainly results from the decomposition of carbonates and the dehydrogenation rather than the cracking of organic matrix. The thermal stability of DCLR mainly depends on the hydrogen donating ability and the solvency of solvent, and THFI formed in the thermal treatment mainly originates from the condensation between oxygen containing functional groups. The spent catalyst in DCLR can inhibit the condensation of THFS, which is more prone to form THFI at lower temperature.