Hydroliquefaction of Australian coals with recycled slurry oil in a 1 kg h −1 continuous reactor

Abstract

Coals from major Australian fields considered as suitable hydroliquefaction feedstocks were hydrogenated in a 1 kg h −1 continuous reactor unit at reaction conditions 415–435 °C and 21 MPa using a stirred flow reactor with retention time of about 2 h. The effect of coal rank and the catalytic effects of disposable iron-based (red mud plus sulphur) catalysts were studied. The system was operated continuously with process-derived recycle solvent for up to 236 h. The time for a single pass of recycle solvent was estimated to be 20 h. Distillate oil yields in the range 35–53% on daf coal were obtained under catalytic operation. The heavier product oils were shown to contain predominantly aromatics, hydroaromatics and phenolics. This indicates that fairly severe hydro-treatment would be required to produce specification diesel and aviation turbine fuels. Recycle solvent composition was observed to stabilize in 2–4 passes after making a process change. These data compare favourably with those obtained on the same coals in larger pilot plants showing that this unit is capable of producing useful yield data.