Phase behavior and process parameters effects on the characteristics of precipitated theophylline using carbon dioxide as antisolvent

2008 ◽  
Vol 44 (1) ◽  
pp. 8-20 ◽  
Author(s):  
Elton Franceschi ◽  
Marcos H. Kunita ◽  
Marcus V. Tres ◽  
Adley F. Rubira ◽  
Edvani C. Muniz ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Phase Behavior ◽  
Process Parameters

Phase Behavior of Hydrogenation of 2-tert-Butylphenol over a Charcoal-Supported Rhodium Catalyst in Carbon Dioxide Solvent†

2009 ◽  
Vol 54 (5) ◽  
pp. 1610-1612 ◽  
Author(s):  
Norihito Hiyoshi ◽  
Yoshio Masuda ◽  
Osamu Sato ◽  
Aritomo Yamaguchi ◽  
Chandrashekhar V. Rode ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Phase Behavior ◽  
Rhodium Catalyst ◽  
Supported Rhodium Catalyst

Effect of Common Impurities on the Phase Behavior of Carbon-Dioxide-Rich Systems: Minimizing the Risk of Hydrate Formation and Two-Phase Flow

SPE Journal ◽  
2011 ◽  
Vol 16 (04) ◽  
pp. 921-930 ◽  
Author(s):  
Antonin Chapoy ◽  
Rod Burgass ◽  
Bahman Tohidi ◽  
J. Michael Austell ◽  
Charles Eickhoff
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Phase Behavior ◽  
Water Content ◽  
Thermodynamic Model ◽  
Two Phase Flow ◽  
Hydrate Formation ◽  
Experimental Methodology ◽  
Phase Flow ◽  
Two Phase

Summary Carbon dioxide (CO2) produced by carbon-capture processes is generally not pure and can contain impurities such as N2, H2, CO, H2 S, and water. The presence of these impurities could lead to challenging flow-assurance issues. The presence of water may result in ice or gas-hydrate formation and cause blockage. Reducing the water content is commonly required to reduce the potential for corrosion, but, for an offshore pipeline system, it is also used as a means of preventing gas-hydrate problems; however, there is little information on the dehydration requirements. Furthermore, the gaseous CO2-rich stream is generally compressed to be transported as liquid or dense-phase in order to avoid two-phase flow and increase in the density of the system. The presence of impurities will also change the system's bubblepoint pressure, hence affecting the compression requirement. The aim of this study is to evaluate the risk of hydrate formation in a CO2-rich stream and to study the phase behavior of CO2 in the presence of common impurities. An experimental methodology was developed for measuring water content in a CO2-rich phase in equilibrium with hydrates. The water content in equilibrium with hydrates at simulated pipeline conditions (e.g., 4°C and up to 190 bar) as well as after simulated choke conditions (e.g., at -2°C and approximately 50 bar) was measured for pure CO2 and a mixture of 2 mol% H2 and 98 mol% CO2. Bubblepoint measurements were also taken for this binary mixture for temperatures ranging from -20 to 25°C. A thermodynamic approach was employed to model the phase equilibria. The experimental data available in the literature on gas solubility in water in binary systems were used in tuning the binary interaction parameters (BIPs). The thermodynamic model was used to predict the phase behavior and the hydrate-dissociation conditions of various CO2-rich streams in the presence of free water and various levels of dehydration (250 and 500 ppm). The results are in good agreement with the available experimental data. The developed experimental methodology and thermodynamic model could provide the necessary data in determining the required dehydration level for CO2-rich systems, as well as minimum pipeline pressure required to avoid two-phase flow, hydrates, and water condensation.

scholarly journals Extraction of Triterpenic Acids and Phytosterols from Apple Pomace with Supercritical Carbon Dioxide: Impact of Process Parameters, Modelling of Kinetics, and Scaling-Up Study

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2790 ◽  
Author(s):  
Łukasz Woźniak ◽  
Anna Szakiel ◽  
Cezary Pączkowski ◽  
Krystian Marszałek ◽  
Sylwia Skąpska ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Process Parameters ◽  
Binary Systems ◽  
Cell Model ◽  
Intact Cell ◽  
Selective Extraction ◽  
Apple Pomace ◽  
Extraction Curve ◽  
Hydrophobic Compounds ◽  
The Impact

Apple pomace, a byproduct of juice production, is a rich source of bioactive compounds and nutrients. Supercritical fluid extraction was proposed as a method for a fast and selective extraction of hydrophobic compounds with a pharmaceutical potential from this matrix. Chromatographic analysis showed that the pomace contained significant amounts of such substances, the most abundant of them were ursolic acid, oleanolic acid, and β-sitosterol. The solubility was chosen as a primary factor for a selection of the extraction conditions; the best results were acquired for a temperature of 80 °C and a pressure of 30 MPa. The equation proposed by Chrastil was applied for the description of the impact of the process parameters on the solubility of the analytes; the obtained values of coefficients of determination were satisfactory, despite the fact that the equation was developed for binary systems. The extraction curves obtained during the experiments were used for the description of the process kinetics using the Broken plus Intact Cell model. The impact of the temperature, pressure, and flow rate of carbon dioxide on the mass transfer phenomena was investigated. The data obtained allowed the prediction of the extraction curve for the process conducted on the larger scale.

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