Experimental techniques for the determination of thermophysical properties to enhance chemical processes

Abstract

It is of utmost importance to have accurate experimental data available in order to develop accurate modeling for scientific and engineering purposes as it is emphasized through several herein-reported discussions with reknown scientists and engineers. Many methods are used to determine phase equilibria. Classification of the methods is not straightforward as several basic principles can be mixed in several different ways. In this paper, we have selected some techniques, developed in our laboratory, to illustrate one type of classification. Several apparatuses are described. The techniques where all phases are analyzed are very often preferred to those relying on partial determinations requiring data treatment through models. The internal analyses by means of spectroscopic or other in situ analysis techniques are not applicable every time. Then, sampling devices are necessary. Sampling devices must be reliable and lead to extract sample amounts small enough not to disturb the equilibrium under study. The ROLSI™ sampler developed at MINES ParisTech is a very powerful device allowing one to work up to 100 MPa, 850 K, with corrosive components and with samples from 1 μg to some mg. Applications of this sampler are described for fundamental research (phase equilibrium measurements) and industrial purposes (process control and monitoring).