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

In many cases of industrial fluid-solid separation process design, a thermo dynamic key parameter may be the sublimation pressure of pure components. A new trend in chemical applications is the use of supercritical solvents ei ther in purifying operations on mixtures of complex pharmaceutical molecule s or in stripping on polluted stuff. Measurements of very low sublimation p ressures of heavy components are very difficult to perform although their v alues are of most importance in the process evaluation. Unfortunately, the prediction tools available in the literature for the estimation of sublimat ion pressures are poor. This paper deals with a consistent approach of subl imation pressure estimation, applicable to any pure material using on one h and easy measurements of normal fusion temperature and fusion enthalpy, and on the:other hand vapor pressure data. The influence of all-the uncertaint ies is discussed and the method is proposed as a new reference with emphasi s on extrapolating reliably to very heavy compounds. By computing vapor Liq uid equilibrium using a cubic equation of state (EOS), the estimation of su blimation pressures is discussed in a new perspective. (C) 1999 Elsevier Sc ience B.V. All rights reserved.