Study on the thermal liquefaction of Xilinguole lignite in solvent at high temperature

In this paper, thermal liquefaction (TL) of Xilinguole lignite (XL) in the range of 400-540 °C have been carried out in toluene, tetralin (THN) and their mixed solvent, respectively. Results indicated that the conversion of XL primarily depends on the hydrogen donor ability of solvent. The highest conversions of XL in toluene and THN were obtained at 480 °C, which are 25.8% and 98.6%, respectively. The condensation of pyrolytic free radicals dominates the TL in toluene solvent but there is hardly obvious coking occurred in THN at below 510 °C. In toluene and THN mixed solvent, the conversion of XL increases with the THN content. The products of TL in toluene mainly consist of oil and gas (O + G) fraction, but the asphaltene (AS) and preasphaltene (PA) factions prevail in the products of TL in THN. Hydrogen donor solvent has obvious improvement on the deoxygenation in the TL process. Therefore, TL in hydrogen donor solvent is a potential conversion technology of XL due to low reaction pressure and without H2 and catalyst used.