Group contribution methods for coal liquids

Abstract

This paper presents a brief summary of the use of group contribution methods for coal derived liquids. Group contribution methods have been used to estimate heat capacity, critical properties, hydrogen solubility and vapor pressure for narrow boiling coal liquid distillates. In general, the group contribution methods provided reasonable estimates of thermophysical properties at moderate temperatures and pressures, using no adjustable parameters. Sensitivity calculations were done to identify the structural features which were most significant in determining coal liquid properties. For most of the properties, the key structural features were aromaticity, degree of substitution on the aromatic rings and phenolic content. This conclusion suggests that a few analytical measurements may be sufficient for characterizing coal liquids. The methods available for determining the key structural features are reviewed and evaluated.