Correlation of chemical constitution and boiling point with separation behaviour during distillation of coal liquid

Abstract

The separation behaviour of coal hydrogenation liquids during distillation was clarified using correlations between chemical structural factors (R a, R n and C al) and boiling points of narrow cut distillation fractions. The separation order according to chemical structure at given distillation temperatures was represented on a three-dimensional R aR nC al diagram. In this diagram, one axis represents the number of aromatic rings in the structure of a compound (R a), one represents the number of naphthenic rings (R n), and the third axis represents the number of alkyl carbons (C al). This diagram is believed to be an appropriate way to handle the analysis of molecules in coal liquids, which are extremely complicated mixtures. Kerosene, light oil and heavy oil from coal liquid were also characterized on this diagram. The distribution ranges of components during separation in distillation agree fairly well with their corresponding distillation temperature range on the R a R nC al diagram proposed. The distillation curve was predicted from the structural analyses with h.p.l.c./g.c.-m.s. and constitution-boiling point correlation as shown in the R aR nC al diagram.