Thermodynamic and rheological properties of solid-liquid systems in coal processing

Abstract

The objective of this project is to develop a model for solid-liquid equilibria and a model for viscosities of the products of coal liquefaction processes. The same characterization procedure and representation by continuous distributions as used in previous work on vapor-liquid equilibria and excess enthalpies of coal liquids will be used. Models when fully developed win give the solid-liquid phase equilibrium properties and viscosities as factors of temperature and pressure for known molecular weight distribution and structural characterization of the coal liquid. To accomplish this well, the project requires three tasks: (1) Solid-Liquid phase equilibrium model development; (2) Experimental Viscosity Measurements; and (3) Viscosity Model Development. A model for viscosity computation of coal model compound liquids and coal derived liquids has been developed. Literature review for this work included compilation of a number of data sets, critical investigation of data measurement techniques available in the literature, and investigation of models for liquid and solid phase thermodynamic computations. During the preliminary stages it was discovered that for development of a liquid or solid state equation of state, accurate predictive models for a number of saturation properties, such as, liquid and solid vapor pressures, saturated liquid and solid volumes, heat capacities of liquids and solids at saturation, etc. Most of the remaining time on this task was spent in developing predictive correlations for vapor pressures and saturated liquid volumes of organic liquids in general and coal model liquids in particular.