Characteristics of residues from thermal and catalytic coal hydroliquefaction☆

The properties of residues from thermal or catalytic coal hydroliquefaction experiments were characterised by the ultimate, proximate analyses. The relations between the properties of the residues and the liquefaction reaction conditions, such as temperature, time, catalyst, H-donor solvent and atmosphere were investigated. Variations in H/C ratio and organic volatile matter (OVM) content of the residues with liquefaction conditions and coal conversion were studied. Results show that liquefaction temperature and time are main factors that control the organic properties of the residues. The roles of the Fe–S catalyst and H-donor solvent are to reduce the proportion of condensation products in the residue rather than increase the extent of polymerisation. Consequently, coal liquefaction conversion is improved by 100% by the catalyst, but H/C ratio and OVM content of the residues are not significantly decreased.