Niramol Juntarachat

La connaissance des propriétés critiques des mélanges binaires est importante pour la conception et le développement des procédés des industries chimiques, mais également, pour l'amélioration et l'extension des modèles thermodynamiques prédictifs. Cependant, des données expérimentales critiques liquide - vapeur de mélanges binaires sont relativement rare dans la littérature. C'est la raison pour laquelle, nous avons acquis un nouvel appareil permettant de mesurer les points critiques de corps purs et de mélanges. Dans une première étape, nous avons mis au point et validé le protocole expérimental, en comparant les résultats de nos mesures aux données de la littérature. Dans une deuxième étape, nous montrons l'intérêt que la mesure de points critiques de mélanges binaires peut présenter pour le développement de deux types de procédés : i) la production de biodiesel par voie supercritique et ii) l'étude de comportement de phases de nouveaux réfrigérants. Les résult...

La connaissance des proprietes critiques des melanges binaires est importante pour la conception et le developpement des procedes des industries chimiques, mais egalement, pour l'amelioration et l'extension des modeles thermodynamiques predictifs. Cependant, des donnees experimentales critiques liquide - vapeur de melanges binaires sont relativement rare dans la litterature. C'est la raison pour laquelle, nous avons acquis un nouvel appareil permettant de mesurer les points critiques de corps purs et de melanges. Dans une premiere etape, nous avons mis au point et valide le protocole experimental, en comparant les resultats de nos mesures aux donnees de la litterature. Dans une deuxieme etape, nous montrons l'interet que la mesure de points critiques de melanges binaires peut presenter pour le developpement de deux types de procedes : i) la production de biodiesel par voie supercritique et ii) l'etude de comportement de phases de nouveaux refrigerants. Les result...

ABSTRACT In this paper the experimental setup of a new apparatus able to provide the critical properties of pure components and mixtures using either a dynamic or a static method is described. Critical temperatures (Tc) and critical pressures (Pc) of pure components (n-pentane, n-heptane and n-decane) and critical loci of three binary mixtures (n-pentane + n-heptane, n-pentane + n-decane and n-heptane + n-decane) are investigated using the dynamic method. For the system n-pentane + n-heptane, the results obtained with the dynamic method are compared with those obtained with the static method. The critical points are visually determined by observing the critical opalescence and the simultaneous disappearance and reappearance of the meniscus in the middle of the view cell which withstands operations up to 673 K and 20 MPa. The experimental critical data are compared with success to literature database and with their prediction from the PPR78 thermodynamic model.

Scientific topic: 2 (equations of state) Abstract Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have a high ozone depletion potential (ODP) and hydrofluorocarbons (HFCs) are high global warming potential (GWP) refrigerants. Consequently, refrigeration and airconditioning industries carry out extensive researches to find highly efficient alternative refrigerants with zero ODP and GWP lower than 150. The search for next-generation refrigerants requires the preselection of good candidate likely to exhibit low environmental impact and leading to high thermodynamic cycle efficiency. To do so, disposing of powerful predictive thermodynamic models is a necessary prerequisite. In this work, the well established E-PPR78 predictive equation of state was extended to systems containing freons. Therefore, 6 different groups were added to the 21 already-existing groups: group 22: CF 3-CF 3 (R116), group 23:-CF 3 , group 24:-CF 2 , group 25: =CF 2 / =CF-, group 26: CHF 2-CH 3 (R1...

ABSTRACT To design and optimize the noncatalytic supercritical process for biodiesel production based on ethanolysis and using carbon dioxide as a cosolvent, thermodynamic models are required to predict the fluid phase equilibria of the various mixtures involved within. This work is an attempt to extend the PPR78 predictive cubic equation of state to CO2 + ethyl ester systems. To do so, 105 mixture critical points of 11 CO2 + (saturated and unsaturated) ethyl ester mixtures were preliminary measured using a synthetic-dynamic apparatus. With the use of these data as well as vapor-liquid equilibrium data collected in the open literature, 2 new groups were added to the PPR78 model (the ester group −COO- and the ethyl acetate group) and 10 PPR78 group-interaction parameter values were determined. Although the PPR78 model offers a good predictive capacity, it is observed that the prediction may deteriorate with the ethyl ester chain length or the presence of double C═C bonds.

ABSTRACT Natural rubber products emit malodourous compounds, which can contaminate the air and water of the inhabited surroundings of the production factories. Analytical methods such as SPME coupled with GC-MS and GC-O-FID were used to elucidate the composition and olfactory impact of volatile compounds released from two various grades of natural rubber submitted to different coagulation processes. Forty-three volatile compounds were identified and amongst 16 of them that had never been reported. The volatile compounds belonged to different chemical classes and were the result of enzymatic and microbial action as well as thermal degradation. Among the new compounds identified, a terpene (limonene), benzyl derivatives, or trimethylamine were found in both grades of natural rubber. In contrary phenyl acids, fatty acid esters, or 2,6 dimethoxyphenol were specific to one grade of natural rubber and may result from the coagulation process. The use of GC-O analysis emphasized the contribution of short-chain fatty acids to the malodorous odour generated but also evidenced the participation of trimethylamine and 2,6 dimethoxyphenol. At last, it was demonstrated that the presence of phenyl acids in one natural rubber could partially mask the obnoxious odour. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1863–1872, 2013