Characterization of Coal Liquids

Abstract

In order to characterize the coal liquids, compound-type separation and analysis of the recycle oils in the liquefaction reaction were investigated and following results were obtained.1) The quantitative separation into five fractions such as acidic, basic, saturated, aromatic, and polar fractions was preferable to evaluate rapidly and simply the recycle oils (Figs. 1 and 3).2) The acidic and basic fractions in the recycle oil can be satisfactorily extracted by 1∼2 M/1 aq. solution of sodium hydroxide and hydrochloric acid, respectively. However, the extraction should be necessarily carried out rapidly (Fig. 2).3) The acidic, saturated, and polar fractions in the recycle oil increased with the number of recycle in the liquefaction reaction. On the contrary, the aromatic fraction decreased (Figs. 4 and 6).4) The major components in saturated fraction were n-paraffins from C13 to C33. The atomic ratio of total carbon to phenolic oxygen in the acidic fraction was about 10. Consequently, it was assumed that the number of aromatic ring was 1∼2 per one phenolic hydroxyl group.The atomic ratio of total carbon to basic nitrogen in the basic fraction was about 14, and accordingly the number of aromatic ring was 1∼2 per one pyridine ring. The average molecular structures were almost independent of the number of recycle in the liquefaction reaction (Figs 7, 8, 9, and Table 1).