Time filter

Source Type

Anzin-Saint-Aubin, France

Barreda F.-A.,University Claude Bernard Lyon 1 | Trichard F.,University Claude Bernard Lyon 1 | Barbier S.,University Claude Bernard Lyon 1 | Gilon N.,University Claude Bernard Lyon 1 | Saint-Jalmes L.,Bluestar Silicones
Analytical and Bioanalytical Chemistry | Year: 2012

The potential of laser-induced breakdown spectroscopy (LIBS) for the rapid determination of platinum in liquid silicone oils has been evaluated in the framework of on-line process control. A comparison of LIBS sensitivity between three setups designed for liquid analysis (static, liquid jet and flowing liquid) was performed using a 266 nm Nd/YAG laser irradiation. Best results were obtained using the flowing liquid setup and a similar limit of detection was obtained using the liquid jet. The effect of different buffer gases (Ar, He, N 2, etc.) on the signal sensitivity was studied in liquid jet analysis and best values were obtained with a nitrogen sheath gas. Detection limits were in the 100 mg/kg range for both setups. Quantitative determination of platinum in real liquid samples was also investigated using both liquid jet and flowing liquid setups. Calibration curves were plotted for Pt with the liquid jet and the flowing liquid setups under optimised temporal acquisition parameters (delay time and gate width). A normalisation using a silicon line was applied and recovery ranged from 3 to 15 % for Pt in catalyst samples with both setups showing that LIBS is a sensitive and accurate method for online applications. © Springer-Verlag 2012.

Jawhar M.-C.D.,University Claude Bernard Lyon 1 | Blanc D.,Bluestar Silicones | Chaumont P.,University Claude Bernard Lyon 1 | Cassagnau P.,University Claude Bernard Lyon 1
Macromolecular Materials and Engineering | Year: 2014

A foam sample is assumed to be a set of bubbles embedded into a polymeric matrix with an initial gas overpressure. Silicon foams are produced by a competition between two reactions involving the hydrogenosilane functions carried by the polymer precursor: the first reaction generates gas (initiating cell formation) while the other one, hydrosilylation, well known and controlled in silicon, leads to the crosslinking of the rising foam. Thus, obtaining enhanced foam properties requires a good balance between two reactions, crosslinking and gas generation. On the other hand, the final characteristics of the foam (porosity, bulk density, etc.) largely depend on the rheology of the mix (appropriate elongational properties) as well as the added fillers. Nucleation and cell growth were carried out under optical microscopy. The experiments show that the main phenomenon controlling cell growth is bubble coalescence. Due to the surface effects and the viscoelastic properties, bubbles approach from each other and get deformed giving birth to an intermediate shape before reaching their final geometry. Many parameters have direct effect on foam properties. In fact, dissolved gas in formulae as well as the air introduced during manual mixing, reduce the skin effect and guarantee a homogeneous cell size distribution and a better foam structure. Other factors have also been studied in order to render size distribution more homogeneous and improve certain properties. Silicon foams are produced by a competition between two reactions: the first generates gas and initiates cell formation while the second leads to the crosslinking of the rising foam. Adequate foam properties require a good balance between these two reactions. Nucleation and cell growth were carried out under optical microscopy. The main phenomenon controlling cell growth is bubble coalescence. Many parameters such as the viscoelastic properties and the surface effects have direct effect on foam properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blazquez C.,Bluestar Silicones | Emond E.,Bluestar Silicones | Schneider S.,Bluestar Silicones | Dalmazzone C.,French Institute of Petroleum | Bergeron V.,CNRS Physics Laboratory
Oil and Gas Science and Technology | Year: 2014

Foams produced from non-aqueous media are less common than water-based foams but they play an important role in many industries and engineering processes. The low surface tension of hydrocarbon fluids limits the adsorption of common surface activity substances and different compounds and methods must be considered to generate and stabilize oil-based foam. Likewise, the destruction of unwanted non-aqueous based foam requires specific considerations not found with aqueous systems. Of particular interest are petroleum-based foams, which are highly complex due to the wide variety of compounds and gases that can be found. We provide an overview of the major mechanisms known to be important for non-aqueous foam stability with a spotlight on crude-oil foams. © 2014, IFP Energies nouvelles.

Blazquez C.,French Institute of Petroleum | Dalmazzone C.,French Institute of Petroleum | Emond E.,Bluestar Silicones | Schneider S.,Bluestar Silicones
Fuel | Year: 2016

Crude oil foams are highly complex non-aqueous foams that tend to form from the release of dissolved gas after an abrupt decrease in the pressure. These foams are typically encountered during crude oil exploitation and refining and especially in oil-gas separation processes. These kinds of foams are widely different from aqueous ones in terms of formation and stabilization and therefore classical methods developed for the study of aqueous foams are no longer useful to reproduce crude oil foam formation conditions. For this reason, we have developed a foam test based on crude oil depressurization to simulate crude oil formation during oil production. Foams can be generated through the laboratory test in a reproducible way and can be consequently characterized in terms of foaminess, stability and kinetics of rupture. Moreover, we also have developed a new methodology to characterize foam stability and liquid foaminess by modeling the crude oil defoaming kinetics. The model we propose allows an easy comparison of the behavior of crude oils foams. By studying different crude oils of known compositions, we have found a correlation between their behavior in term of stability and foaminess and a parameter that takes into account the crude viscosity and its composition. © 2015 Elsevier Ltd. All rights reserved.

Discover hidden collaborations