A Study of Physical Properties of Brown Coal Liquid Fraction

Physico-chemical properties of brown coal liquids are scarce. Therefore we have measured such properties as ultimate analysis, structure analysis, molecular weight, density, boiling point, vapor pressure, heat of vaporization, specific heat, surface tension, viscosity and thermal conductivity of Morwell brown coal liquids. A knowledge of these properties is necessary for the design of a coal liquefaction plant, and thus both their measurement and estimation are very important. Boiling point, specific heat, surface tension and thermal conductivity were in linear correlation to molecular weight. As for density, correction with oxygen content and hydrogen/carbon ratio is considered to be reasonable from the results of continuous change of density with boiling point. Antoine vapor-pressure correlation was observed for each fraction. Heat of vaporization decreased with increase of molecular weight. The logarithm of viscosity was in linear correlation to molecular weight. From the overall viewpoint, the behavior of these liquids is similar to that of ordinary organic liquids, but as can be seen from the behavior of density and viscosity, these liquids have a somewhat different liquid structure from that of nonpolar organic liquids.