A consistent estimation of sublimation pressures using a cubic equation of state and fusion properties

In many cases of industrial fluid-solid separation process design, a thermodynamic key parameter may be the sublimation pressure of pure components. A new trend in chemical applications is the use of supercritical solvents either in purifying operations on mixtures of complex pharmaceutical molecules or in stripping on polluted stuff. Measurements of very low sublimation pressures of heavy components are very difficult to perform although their values are of most importance in the process evaluation. Unfortunately, the prediction tools available in the literature for the estimation of sublimation pressures are poor. This paper deals with a consistent approach of sublimation pressure estimation, applicable to any pure material using on one hand easy measurements of normal fusion temperature and fusion enthalpy, and on the:other hand vapor pressure data. The influence of all-the uncertainties is discussed and the method is proposed as a new reference with emphasis on extrapolating reliably to very heavy compounds. By computing vapor Liquid equilibrium using a cubic equation of state (EOS), the estimation of sublimation pressures is discussed in a new perspective. (C) 1999 Elsevier Science B.V. All rights reserved.