The Scott-Magat Polymer Theory for Determining Onset of Precipitation of Dissolved Asphaltene in the Solvent + Precipitant Solution

This article has been published in an open access journal and is also available at http://www.benthamscience.com/open/totherj/articles/V002/13TOTHERJ.pdfInternational audienceThe Scott-Magat polymer theory, which assumes that polymers have heterogeneous structure and takes into account the polydispersity in the molecular weight of polymers, is a method to model asphaltene precipitation conditions. The traditional Scott-Magat polymer theory based models assume that the precipitated phase consists of asphaltene only. In the present work, we introduce a model based on the Scott-Magat polymer theory assuming that the precipitated phase consists of asphaltene and non-asphaltene components and the oil phase is free of asphaltene (Due to low concentration of asphaltene in the oil phase). It is shown that the latter model is similar to a previously reported thermodynamic model in the literature based on the Flory-Huggins polymer theory (R. Cimino, S. Correra, P.A. Sacomani, C. Carniani, "Thermodynamic Modelling for Prediction of Asphaltene Deposition in Live Oils", SPE 28993, Presented at the SPE International Symposium on Oilfield Chemistry held in San Antonio, TX, USA, 14-17 February 1995), in which it is assumed that asphaltene has a homogeneous structure and the precipitated phase consists of asphaltene and non-asphaltene components and the oil phase is free of asphaltene

Hydrates (clathrates) d’isopentane + dioxyde de carbone et d’isopentane + méthane : Déterminations expérimentales des conditions de dissociation

International audienceIn this work, experimental dissociation data for clathrate hydrates of isopentane + carbon dioxide and isopentane + methane are reported in the temperature ranges of (273.5-282.4) and (275.5-285.7) K, respectively. The experimental data were generated using an isochoric pressure-search method. The reliability of this method is examined by generating new dissociation data for clathrate hydrates of isopentane + methane and comparing them with the experimental data reported in the literature. The acceptable agreement demonstrates the reliability of the experimental method used in this work. The experimental data for all measured systems are finally compared with the corresponding experimental data in the absence of isopentane reported in the literature to identify its promotion effects

Modelling solid solubilities in SC-CO2 and cosolvent : development of enhanced density-based models

International audienceThe solubility of a solid of pharmaceutical interest in supercritical carbon dioxide, with or without cosolvent has been measured by means of a novel apparatus. This solubility data has been correlated by means of several density–based semi–empirical models, which have been extended and modified to be applicable to mixtures with cosolvent

Isothermal phase (vapour + liquid) equilibrium data for binary mixturesof propene (R1270) with either 1,1,2,3,3,3-hexafluoro-1-propene(R1216) or 2,2,3-trifluoro-3-(trifluoromethyl)oxirane in the temperature range of (279 to 318) K range.

International audienceIsothermal (vapour + liquid) equilibrium data (P–x–y) are presented for the 1-propene +1,1,2,3,3,3-hexafluoro-1-propene and the 1-propene + 2,2,3-trifluoro-3-(trifluoromethyl)oxirane binary systems. Both binary systems were studied at five temperatures, ranging from (279.36 to 318.09) K, atpressures up to 2 MPa. The experimental (vapour + liquid) equilibrium data were measured using an apparatus based on the ‘‘(static + analytic)’’ method incorporating a single movable Rapid On-Line Sampler-Injector to sample the liquid and vapour phases at equilibrium. The expanded uncertainties are approximated on average as = 0.07 K, 0.008 MPa, and 0.007 and 0.009 for the temperature, pressure, and the liquid and vapour mole fractions, respectively. A homogenous maximum-pressure azeotrope was observed for both binary systems at all temperatures studied. The experimental data were correlated with the Peng–Robinson equation of state using the Mathias–Copeman alpha function, paired with theWong–Sandler mixing rule and the Non-Random Two Liquid activity coefficient model. The model provided satisfactory representation of the phase equilibrium data measure

Phase equilibrium data for the hydrogen sulphide + methane system at temperatures from 186 to 313 K and pressures up to about 14 MPa

International audienceIsothermal vapour–liquid equilibrium data have been measured for the methane–hydrogen sulphide (CH4 + H2S) binary system at five temperatures from 186.25 to 313.08 K, and pressures between 0.043 and 13.182 MPa. The experimental method used in this work is of the static–analytic type, taking advantage of two pneumatic capillary samplers (RolsiTM, Armines’ patent) developed in the CTP laboratory. The data were obtained with the following maximum expanded uncertainties (k = 2): u(T) = 0.06 K, u(P) = 0.006 MPa and the maximum uncertainty for compositions u(x, y) = 0.010 for molar compositions. The data have been satisfactorily represented with the classical Peng and Robinson equation of state

New equipment and new technique for measuring activity coefficients and Henrys constants at infinite dilution

Erratum: "New equipment and new technique for measuring activity coefficients and Henry's constants at infinite dilution" [Rev. Sci. Instrum. 82, 025108 (2011)] Dominique Richon Rev. Sci. Instrum. 82, 039902 (2011) DOI: 10.1063/1.3572261International audienceNew equipment is presented along with various experimental procedures and setups to cover a large range of applications. It represents a considerable improvement in terms of speed, accuracy, and simplicity with respect to classical gas stripping methods known as dilutor techniques. Furthermore, range of conditions of its use is larger in terms of: temperatures (from 90 to 600 K), corrosive power, and toxicity of handled compounds. Solutes that could adsorb inside sampling valves or on the walls of transfer lines between sampling valve and GC detector are now studied easily; thanks to new design and procedure. Activity coefficients of one solute into one solvent at five temperatures, several repeatability tests included, are obtained in worst cases in less than 3 h. One accurate activity coefficient measurement (toluene in water) at one temperature can be realized in less than 2 min, after loading of the dilutor cell, instead of more than half an hour for unreliable results with previous equipment. It must be pointed out that the slope determination (slope of the logarithm of the exponential decay of solute composition in vapor phase which is in equilibrium with liquid phase) is the highest source of errors (flow rate, temperature, number of moles of solute are known with high accuracy with respect to slopes); they are now determined within few % instead of up to tens of % in the most difficult cases leading to higher accuracies of measured activity coefficients, Henrys constants at infinite dilutions or solubility data. Successful comparisons with literature data and reproducibility tests are presented herein

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

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)

Etude des proprietes volumétriques (PVT) d hydrocarbures legers (c1-c4), du dioxyde de carbone et du sulfure d hydrogène (mesures par densimétrie à tube vibrant et modélisation)

PARIS-MINES ParisTech (751062310) / SudocSudocFranceF