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

Abstract

Paper based on a presentation at the 20th International Conference on Chemical Thermodynamics (ICCT 20), 3–8 August 2008, Warsaw, Poland. Other presentations are published in this issue, pp. 1719–1959International audienceIt 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 straight- forward 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 classifi- cation. 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 de- vices must be reliable and lead to extract sample amounts small enough not to disturb the equilibrium under study. The ROLSITM 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 funda- mental research (phase equilibrium measurements) and industrial purposes (process control and monitoring)

Measurement of vapor–liquid–liquid phase equilibrium—Equipment and results

“…The equilibrium cell is fitted with two automatic electromagnetic capillary ROLSI™ samplers [6,7] Developed specifically for the purpose of phase equilibria studies, the ROLSI™ samplers have been established as a reference worldwide, being currently used in many universities as well as in industry. In many research groups considered as a reference for phase equilibrium and petroleum related studies [8][9][10][11][12][13][14][15]. These sampler-injectors are electromagnetic valves that allow samples to be taken from each of the phases without disturbing the phases in equilibrium, and vaporizing the liquid ones directly to the carrier gas stream of a gas chromatograph, without any manipulation of the samples.…”

High-pressure experimental vapour-liquid-liquid equilibrium measurements and modelling for natural gas processing: Equipment validation, and the system CH4+nC6H14+H2O

“…For this reason, new experimental data are measured. The importance of experimental data cannot be overstated, as was highlighted in a statement by Prof. Dominique Richon: [3] "Some people think that experimental work, compared to modelling and simulation, is more tedious, more expensive, and less appreciated in our community. However, numerous e-mail exchanges have confirmed my feeling that good thermodynamic data are absolutely necessary, because process design relies on accurate modelling and accurate modelling relies on reliable experimental data.…”

Near infrared spectroscopy applied for high-pressure phase behavior measurements

“…This information is essential for the design and optimization of high-pressure chemical processes, separation operations [1], and for the efficient modeling and simulation of thermodynamic behavior and phase diagrams at high pressure [2]. Normally, the selection of the experimental technique is based on the system characteristics, such as the chemical nature and physical properties of mixture, range of pressure and temperature, and type of equilibrium data to be investigated.…”