VISCOSITY OF COAL-DERIVED LIQUIDS .2. APPLICATION OF THE MODEL TO COAL LIQUID FRACTIONS

The group contribution viscosity model for pure coal model liquids des cribed in a previous paper (Energy Fuels 1995, 10, 333) has been succe ssfully extended to binary liquid mixtures of coal model compounds, an d a procedure has been developed to use the model for computation of v iscosities of coal-derived liquids. It is shown that simple mixing rul es, or even a pseudopure component model, is adequate to estimate mixt ure viscosity within reasonable accuracy for these compounds. For appl ication of the model to coal-derived liquids, a data set on SRC-II coa l liquid cuts available in the literature has been used. Sufficient ch emical analysis data were available for these cuts to make the applica tion of our model possible. The computational procedure involved trans formation of the analytical data into functional group characterizatio n of the coal liquid. Central to this procedure was the definition of types and distributions of various ring structures in multiring compou nds. When compared to limited studies available in the literature, thi s model predicts viscosities of coal liquids with better accuracy. Ove rall, this is the first viscosity model that has been developed for th e type of structures that exist in coal-derived liquids, and provides a reasonably accurate procedure for computation of viscosities of narr ow boiling coal liquid cuts, a property that is necessary in designing efficient coal liquefaction processes.